git.oblomov.eu Git - git/blob - diff.c

   1 /*
   2  * Copyright (C) 2005 Junio C Hamano
   3  */
   4 #include "cache.h"
   5 #include "config.h"
   6 #include "tempfile.h"
   7 #include "quote.h"
   8 #include "diff.h"
   9 #include "diffcore.h"
  10 #include "delta.h"
  11 #include "xdiff-interface.h"
  12 #include "color.h"
  13 #include "attr.h"
  14 #include "run-command.h"
  15 #include "utf8.h"
  16 #include "object-store.h"
  17 #include "userdiff.h"
  18 #include "submodule-config.h"
  19 #include "submodule.h"
  20 #include "hashmap.h"
  21 #include "ll-merge.h"
  22 #include "string-list.h"
  23 #include "argv-array.h"
  24 #include "graph.h"
  25 #include "packfile.h"
  26 #include "parse-options.h"
  27 #include "help.h"
  28
  29 #ifdef NO_FAST_WORKING_DIRECTORY
  30 #define FAST_WORKING_DIRECTORY 0
  31 #else
  32 #define FAST_WORKING_DIRECTORY 1
  33 #endif
  34
  35 static int diff_detect_rename_default;
  36 static int diff_indent_heuristic = 1;
  37 static int diff_rename_limit_default = 400;
  38 static int diff_suppress_blank_empty;
  39 static int diff_use_color_default = -1;
  40 static int diff_color_moved_default;
  41 static int diff_color_moved_ws_default;
  42 static int diff_context_default = 3;
  43 static int diff_interhunk_context_default;
  44 static const char *diff_word_regex_cfg;
  45 static const char *external_diff_cmd_cfg;
  46 static const char *diff_order_file_cfg;
  47 int diff_auto_refresh_index = 1;
  48 static int diff_mnemonic_prefix;
  49 static int diff_no_prefix;
  50 static int diff_stat_graph_width;
  51 static int diff_dirstat_permille_default = 30;
  52 static struct diff_options default_diff_options;
  53 static long diff_algorithm;
  54 static unsigned ws_error_highlight_default = WSEH_NEW;
  55
  56 static char diff_colors[][COLOR_MAXLEN] = {
  57         GIT_COLOR_RESET,
  58         GIT_COLOR_NORMAL,       /* CONTEXT */
  59         GIT_COLOR_BOLD,         /* METAINFO */
  60         GIT_COLOR_CYAN,         /* FRAGINFO */
  61         GIT_COLOR_RED,          /* OLD */
  62         GIT_COLOR_GREEN,        /* NEW */
  63         GIT_COLOR_YELLOW,       /* COMMIT */
  64         GIT_COLOR_BG_RED,       /* WHITESPACE */
  65         GIT_COLOR_NORMAL,       /* FUNCINFO */
  66         GIT_COLOR_BOLD_MAGENTA, /* OLD_MOVED */
  67         GIT_COLOR_BOLD_BLUE,    /* OLD_MOVED ALTERNATIVE */
  68         GIT_COLOR_FAINT,        /* OLD_MOVED_DIM */
  69         GIT_COLOR_FAINT_ITALIC, /* OLD_MOVED_ALTERNATIVE_DIM */
  70         GIT_COLOR_BOLD_CYAN,    /* NEW_MOVED */
  71         GIT_COLOR_BOLD_YELLOW,  /* NEW_MOVED ALTERNATIVE */
  72         GIT_COLOR_FAINT,        /* NEW_MOVED_DIM */
  73         GIT_COLOR_FAINT_ITALIC, /* NEW_MOVED_ALTERNATIVE_DIM */
  74         GIT_COLOR_FAINT,        /* CONTEXT_DIM */
  75         GIT_COLOR_FAINT_RED,    /* OLD_DIM */
  76         GIT_COLOR_FAINT_GREEN,  /* NEW_DIM */
  77         GIT_COLOR_BOLD,         /* CONTEXT_BOLD */
  78         GIT_COLOR_BOLD_RED,     /* OLD_BOLD */
  79         GIT_COLOR_BOLD_GREEN,   /* NEW_BOLD */
  80 };
  81
  82 static const char *color_diff_slots[] = {
  83         [DIFF_CONTEXT]                = "context",
  84         [DIFF_METAINFO]               = "meta",
  85         [DIFF_FRAGINFO]               = "frag",
  86         [DIFF_FILE_OLD]               = "old",
  87         [DIFF_FILE_NEW]               = "new",
  88         [DIFF_COMMIT]                 = "commit",
  89         [DIFF_WHITESPACE]             = "whitespace",
  90         [DIFF_FUNCINFO]               = "func",
  91         [DIFF_FILE_OLD_MOVED]         = "oldMoved",
  92         [DIFF_FILE_OLD_MOVED_ALT]     = "oldMovedAlternative",
  93         [DIFF_FILE_OLD_MOVED_DIM]     = "oldMovedDimmed",
  94         [DIFF_FILE_OLD_MOVED_ALT_DIM] = "oldMovedAlternativeDimmed",
  95         [DIFF_FILE_NEW_MOVED]         = "newMoved",
  96         [DIFF_FILE_NEW_MOVED_ALT]     = "newMovedAlternative",
  97         [DIFF_FILE_NEW_MOVED_DIM]     = "newMovedDimmed",
  98         [DIFF_FILE_NEW_MOVED_ALT_DIM] = "newMovedAlternativeDimmed",
  99         [DIFF_CONTEXT_DIM]            = "contextDimmed",
 100         [DIFF_FILE_OLD_DIM]           = "oldDimmed",
 101         [DIFF_FILE_NEW_DIM]           = "newDimmed",
 102         [DIFF_CONTEXT_BOLD]           = "contextBold",
 103         [DIFF_FILE_OLD_BOLD]          = "oldBold",
 104         [DIFF_FILE_NEW_BOLD]          = "newBold",
 105 };
 106
 107 static NORETURN void die_want_option(const char *option_name)
 108 {
 109         die(_("option '%s' requires a value"), option_name);
 110 }
 111
 112 define_list_config_array_extra(color_diff_slots, {"plain"});
 113
 114 static int parse_diff_color_slot(const char *var)
 115 {
 116         if (!strcasecmp(var, "plain"))
 117                 return DIFF_CONTEXT;
 118         return LOOKUP_CONFIG(color_diff_slots, var);
 119 }
 120
 121 static int parse_dirstat_params(struct diff_options *options, const char *params_string,
 122                                 struct strbuf *errmsg)
 123 {
 124         char *params_copy = xstrdup(params_string);
 125         struct string_list params = STRING_LIST_INIT_NODUP;
 126         int ret = 0;
 127         int i;
 128
 129         if (*params_copy)
 130                 string_list_split_in_place(&params, params_copy, ',', -1);
 131         for (i = 0; i < params.nr; i++) {
 132                 const char *p = params.items[i].string;
 133                 if (!strcmp(p, "changes")) {
 134                         options->flags.dirstat_by_line = 0;
 135                         options->flags.dirstat_by_file = 0;
 136                 } else if (!strcmp(p, "lines")) {
 137                         options->flags.dirstat_by_line = 1;
 138                         options->flags.dirstat_by_file = 0;
 139                 } else if (!strcmp(p, "files")) {
 140                         options->flags.dirstat_by_line = 0;
 141                         options->flags.dirstat_by_file = 1;
 142                 } else if (!strcmp(p, "noncumulative")) {
 143                         options->flags.dirstat_cumulative = 0;
 144                 } else if (!strcmp(p, "cumulative")) {
 145                         options->flags.dirstat_cumulative = 1;
 146                 } else if (isdigit(*p)) {
 147                         char *end;
 148                         int permille = strtoul(p, &end, 10) * 10;
 149                         if (*end == '.' && isdigit(*++end)) {
 150                                 /* only use first digit */
 151                                 permille += *end - '0';
 152                                 /* .. and ignore any further digits */
 153                                 while (isdigit(*++end))
 154                                         ; /* nothing */
 155                         }
 156                         if (!*end)
 157                                 options->dirstat_permille = permille;
 158                         else {
 159                                 strbuf_addf(errmsg, _("  Failed to parse dirstat cut-off percentage '%s'\n"),
 160                                             p);
 161                                 ret++;
 162                         }
 163                 } else {
 164                         strbuf_addf(errmsg, _("  Unknown dirstat parameter '%s'\n"), p);
 165                         ret++;
 166                 }
 167
 168         }
 169         string_list_clear(&params, 0);
 170         free(params_copy);
 171         return ret;
 172 }
 173
 174 static int parse_submodule_params(struct diff_options *options, const char *value)
 175 {
 176         if (!strcmp(value, "log"))
 177                 options->submodule_format = DIFF_SUBMODULE_LOG;
 178         else if (!strcmp(value, "short"))
 179                 options->submodule_format = DIFF_SUBMODULE_SHORT;
 180         else if (!strcmp(value, "diff"))
 181                 options->submodule_format = DIFF_SUBMODULE_INLINE_DIFF;
 182         else
 183                 return -1;
 184         return 0;
 185 }
 186
 187 int git_config_rename(const char *var, const char *value)
 188 {
 189         if (!value)
 190                 return DIFF_DETECT_RENAME;
 191         if (!strcasecmp(value, "copies") || !strcasecmp(value, "copy"))
 192                 return  DIFF_DETECT_COPY;
 193         return git_config_bool(var,value) ? DIFF_DETECT_RENAME : 0;
 194 }
 195
 196 long parse_algorithm_value(const char *value)
 197 {
 198         if (!value)
 199                 return -1;
 200         else if (!strcasecmp(value, "myers") || !strcasecmp(value, "default"))
 201                 return 0;
 202         else if (!strcasecmp(value, "minimal"))
 203                 return XDF_NEED_MINIMAL;
 204         else if (!strcasecmp(value, "patience"))
 205                 return XDF_PATIENCE_DIFF;
 206         else if (!strcasecmp(value, "histogram"))
 207                 return XDF_HISTOGRAM_DIFF;
 208         return -1;
 209 }
 210
 211 static int parse_one_token(const char **arg, const char *token)
 212 {
 213         const char *rest;
 214         if (skip_prefix(*arg, token, &rest) && (!*rest || *rest == ',')) {
 215                 *arg = rest;
 216                 return 1;
 217         }
 218         return 0;
 219 }
 220
 221 static int parse_ws_error_highlight(const char *arg)
 222 {
 223         const char *orig_arg = arg;
 224         unsigned val = 0;
 225
 226         while (*arg) {
 227                 if (parse_one_token(&arg, "none"))
 228                         val = 0;
 229                 else if (parse_one_token(&arg, "default"))
 230                         val = WSEH_NEW;
 231                 else if (parse_one_token(&arg, "all"))
 232                         val = WSEH_NEW | WSEH_OLD | WSEH_CONTEXT;
 233                 else if (parse_one_token(&arg, "new"))
 234                         val |= WSEH_NEW;
 235                 else if (parse_one_token(&arg, "old"))
 236                         val |= WSEH_OLD;
 237                 else if (parse_one_token(&arg, "context"))
 238                         val |= WSEH_CONTEXT;
 239                 else {
 240                         return -1 - (int)(arg - orig_arg);
 241                 }
 242                 if (*arg)
 243                         arg++;
 244         }
 245         return val;
 246 }
 247
 248 /*
 249  * These are to give UI layer defaults.
 250  * The core-level commands such as git-diff-files should
 251  * never be affected by the setting of diff.renames
 252  * the user happens to have in the configuration file.
 253  */
 254 void init_diff_ui_defaults(void)
 255 {
 256         diff_detect_rename_default = DIFF_DETECT_RENAME;
 257 }
 258
 259 int git_diff_heuristic_config(const char *var, const char *value, void *cb)
 260 {
 261         if (!strcmp(var, "diff.indentheuristic"))
 262                 diff_indent_heuristic = git_config_bool(var, value);
 263         return 0;
 264 }
 265
 266 static int parse_color_moved(const char *arg)
 267 {
 268         switch (git_parse_maybe_bool(arg)) {
 269         case 0:
 270                 return COLOR_MOVED_NO;
 271         case 1:
 272                 return COLOR_MOVED_DEFAULT;
 273         default:
 274                 break;
 275         }
 276
 277         if (!strcmp(arg, "no"))
 278                 return COLOR_MOVED_NO;
 279         else if (!strcmp(arg, "plain"))
 280                 return COLOR_MOVED_PLAIN;
 281         else if (!strcmp(arg, "blocks"))
 282                 return COLOR_MOVED_BLOCKS;
 283         else if (!strcmp(arg, "zebra"))
 284                 return COLOR_MOVED_ZEBRA;
 285         else if (!strcmp(arg, "default"))
 286                 return COLOR_MOVED_DEFAULT;
 287         else if (!strcmp(arg, "dimmed-zebra"))
 288                 return COLOR_MOVED_ZEBRA_DIM;
 289         else if (!strcmp(arg, "dimmed_zebra"))
 290                 return COLOR_MOVED_ZEBRA_DIM;
 291         else
 292                 return error(_("color moved setting must be one of 'no', 'default', 'blocks', 'zebra', 'dimmed-zebra', 'plain'"));
 293 }
 294
 295 static unsigned parse_color_moved_ws(const char *arg)
 296 {
 297         int ret = 0;
 298         struct string_list l = STRING_LIST_INIT_DUP;
 299         struct string_list_item *i;
 300
 301         string_list_split(&l, arg, ',', -1);
 302
 303         for_each_string_list_item(i, &l) {
 304                 struct strbuf sb = STRBUF_INIT;
 305                 strbuf_addstr(&sb, i->string);
 306                 strbuf_trim(&sb);
 307
 308                 if (!strcmp(sb.buf, "ignore-space-change"))
 309                         ret |= XDF_IGNORE_WHITESPACE_CHANGE;
 310                 else if (!strcmp(sb.buf, "ignore-space-at-eol"))
 311                         ret |= XDF_IGNORE_WHITESPACE_AT_EOL;
 312                 else if (!strcmp(sb.buf, "ignore-all-space"))
 313                         ret |= XDF_IGNORE_WHITESPACE;
 314                 else if (!strcmp(sb.buf, "allow-indentation-change"))
 315                         ret |= COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE;
 316                 else {
 317                         ret |= COLOR_MOVED_WS_ERROR;
 318                         error(_("unknown color-moved-ws mode '%s', possible values are 'ignore-space-change', 'ignore-space-at-eol', 'ignore-all-space', 'allow-indentation-change'"), sb.buf);
 319                 }
 320
 321                 strbuf_release(&sb);
 322         }
 323
 324         if ((ret & COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE) &&
 325             (ret & XDF_WHITESPACE_FLAGS)) {
 326                 error(_("color-moved-ws: allow-indentation-change cannot be combined with other white space modes"));
 327                 ret |= COLOR_MOVED_WS_ERROR;
 328         }
 329
 330         string_list_clear(&l, 0);
 331
 332         return ret;
 333 }
 334
 335 int git_diff_ui_config(const char *var, const char *value, void *cb)
 336 {
 337         if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 338                 diff_use_color_default = git_config_colorbool(var, value);
 339                 return 0;
 340         }
 341         if (!strcmp(var, "diff.colormoved")) {
 342                 int cm = parse_color_moved(value);
 343                 if (cm < 0)
 344                         return -1;
 345                 diff_color_moved_default = cm;
 346                 return 0;
 347         }
 348         if (!strcmp(var, "diff.colormovedws")) {
 349                 unsigned cm = parse_color_moved_ws(value);
 350                 if (cm & COLOR_MOVED_WS_ERROR)
 351                         return -1;
 352                 diff_color_moved_ws_default = cm;
 353                 return 0;
 354         }
 355         if (!strcmp(var, "diff.context")) {
 356                 diff_context_default = git_config_int(var, value);
 357                 if (diff_context_default < 0)
 358                         return -1;
 359                 return 0;
 360         }
 361         if (!strcmp(var, "diff.interhunkcontext")) {
 362                 diff_interhunk_context_default = git_config_int(var, value);
 363                 if (diff_interhunk_context_default < 0)
 364                         return -1;
 365                 return 0;
 366         }
 367         if (!strcmp(var, "diff.renames")) {
 368                 diff_detect_rename_default = git_config_rename(var, value);
 369                 return 0;
 370         }
 371         if (!strcmp(var, "diff.autorefreshindex")) {
 372                 diff_auto_refresh_index = git_config_bool(var, value);
 373                 return 0;
 374         }
 375         if (!strcmp(var, "diff.mnemonicprefix")) {
 376                 diff_mnemonic_prefix = git_config_bool(var, value);
 377                 return 0;
 378         }
 379         if (!strcmp(var, "diff.noprefix")) {
 380                 diff_no_prefix = git_config_bool(var, value);
 381                 return 0;
 382         }
 383         if (!strcmp(var, "diff.statgraphwidth")) {
 384                 diff_stat_graph_width = git_config_int(var, value);
 385                 return 0;
 386         }
 387         if (!strcmp(var, "diff.external"))
 388                 return git_config_string(&external_diff_cmd_cfg, var, value);
 389         if (!strcmp(var, "diff.wordregex"))
 390                 return git_config_string(&diff_word_regex_cfg, var, value);
 391         if (!strcmp(var, "diff.orderfile"))
 392                 return git_config_pathname(&diff_order_file_cfg, var, value);
 393
 394         if (!strcmp(var, "diff.ignoresubmodules"))
 395                 handle_ignore_submodules_arg(&default_diff_options, value);
 396
 397         if (!strcmp(var, "diff.submodule")) {
 398                 if (parse_submodule_params(&default_diff_options, value))
 399                         warning(_("Unknown value for 'diff.submodule' config variable: '%s'"),
 400                                 value);
 401                 return 0;
 402         }
 403
 404         if (!strcmp(var, "diff.algorithm")) {
 405                 diff_algorithm = parse_algorithm_value(value);
 406                 if (diff_algorithm < 0)
 407                         return -1;
 408                 return 0;
 409         }
 410
 411         if (!strcmp(var, "diff.wserrorhighlight")) {
 412                 int val = parse_ws_error_highlight(value);
 413                 if (val < 0)
 414                         return -1;
 415                 ws_error_highlight_default = val;
 416                 return 0;
 417         }
 418
 419         if (git_color_config(var, value, cb) < 0)
 420                 return -1;
 421
 422         return git_diff_basic_config(var, value, cb);
 423 }
 424
 425 int git_diff_basic_config(const char *var, const char *value, void *cb)
 426 {
 427         const char *name;
 428
 429         if (!strcmp(var, "diff.renamelimit")) {
 430                 diff_rename_limit_default = git_config_int(var, value);
 431                 return 0;
 432         }
 433
 434         if (userdiff_config(var, value) < 0)
 435                 return -1;
 436
 437         if (skip_prefix(var, "diff.color.", &name) ||
 438             skip_prefix(var, "color.diff.", &name)) {
 439                 int slot = parse_diff_color_slot(name);
 440                 if (slot < 0)
 441                         return 0;
 442                 if (!value)
 443                         return config_error_nonbool(var);
 444                 return color_parse(value, diff_colors[slot]);
 445         }
 446
 447         /* like GNU diff's --suppress-blank-empty option  */
 448         if (!strcmp(var, "diff.suppressblankempty") ||
 449                         /* for backwards compatibility */
 450                         !strcmp(var, "diff.suppress-blank-empty")) {
 451                 diff_suppress_blank_empty = git_config_bool(var, value);
 452                 return 0;
 453         }
 454
 455         if (!strcmp(var, "diff.dirstat")) {
 456                 struct strbuf errmsg = STRBUF_INIT;
 457                 default_diff_options.dirstat_permille = diff_dirstat_permille_default;
 458                 if (parse_dirstat_params(&default_diff_options, value, &errmsg))
 459                         warning(_("Found errors in 'diff.dirstat' config variable:\n%s"),
 460                                 errmsg.buf);
 461                 strbuf_release(&errmsg);
 462                 diff_dirstat_permille_default = default_diff_options.dirstat_permille;
 463                 return 0;
 464         }
 465
 466         if (git_diff_heuristic_config(var, value, cb) < 0)
 467                 return -1;
 468
 469         return git_default_config(var, value, cb);
 470 }
 471
 472 static char *quote_two(const char *one, const char *two)
 473 {
 474         int need_one = quote_c_style(one, NULL, NULL, 1);
 475         int need_two = quote_c_style(two, NULL, NULL, 1);
 476         struct strbuf res = STRBUF_INIT;
 477
 478         if (need_one + need_two) {
 479                 strbuf_addch(&res, '"');
 480                 quote_c_style(one, &res, NULL, 1);
 481                 quote_c_style(two, &res, NULL, 1);
 482                 strbuf_addch(&res, '"');
 483         } else {
 484                 strbuf_addstr(&res, one);
 485                 strbuf_addstr(&res, two);
 486         }
 487         return strbuf_detach(&res, NULL);
 488 }
 489
 490 static const char *external_diff(void)
 491 {
 492         static const char *external_diff_cmd = NULL;
 493         static int done_preparing = 0;
 494
 495         if (done_preparing)
 496                 return external_diff_cmd;
 497         external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 498         if (!external_diff_cmd)
 499                 external_diff_cmd = external_diff_cmd_cfg;
 500         done_preparing = 1;
 501         return external_diff_cmd;
 502 }
 503
 504 /*
 505  * Keep track of files used for diffing. Sometimes such an entry
 506  * refers to a temporary file, sometimes to an existing file, and
 507  * sometimes to "/dev/null".
 508  */
 509 static struct diff_tempfile {
 510         /*
 511          * filename external diff should read from, or NULL if this
 512          * entry is currently not in use:
 513          */
 514         const char *name;
 515
 516         char hex[GIT_MAX_HEXSZ + 1];
 517         char mode[10];
 518
 519         /*
 520          * If this diff_tempfile instance refers to a temporary file,
 521          * this tempfile object is used to manage its lifetime.
 522          */
 523         struct tempfile *tempfile;
 524 } diff_temp[2];
 525
 526 struct emit_callback {
 527         int color_diff;
 528         unsigned ws_rule;
 529         int blank_at_eof_in_preimage;
 530         int blank_at_eof_in_postimage;
 531         int lno_in_preimage;
 532         int lno_in_postimage;
 533         const char **label_path;
 534         struct diff_words_data *diff_words;
 535         struct diff_options *opt;
 536         struct strbuf *header;
 537 };
 538
 539 static int count_lines(const char *data, int size)
 540 {
 541         int count, ch, completely_empty = 1, nl_just_seen = 0;
 542         count = 0;
 543         while (0 < size--) {
 544                 ch = *data++;
 545                 if (ch == '\n') {
 546                         count++;
 547                         nl_just_seen = 1;
 548                         completely_empty = 0;
 549                 }
 550                 else {
 551                         nl_just_seen = 0;
 552                         completely_empty = 0;
 553                 }
 554         }
 555         if (completely_empty)
 556                 return 0;
 557         if (!nl_just_seen)
 558                 count++; /* no trailing newline */
 559         return count;
 560 }
 561
 562 static int fill_mmfile(struct repository *r, mmfile_t *mf,
 563                        struct diff_filespec *one)
 564 {
 565         if (!DIFF_FILE_VALID(one)) {
 566                 mf->ptr = (char *)""; /* does not matter */
 567                 mf->size = 0;
 568                 return 0;
 569         }
 570         else if (diff_populate_filespec(r, one, 0))
 571                 return -1;
 572
 573         mf->ptr = one->data;
 574         mf->size = one->size;
 575         return 0;
 576 }
 577
 578 /* like fill_mmfile, but only for size, so we can avoid retrieving blob */
 579 static unsigned long diff_filespec_size(struct repository *r,
 580                                         struct diff_filespec *one)
 581 {
 582         if (!DIFF_FILE_VALID(one))
 583                 return 0;
 584         diff_populate_filespec(r, one, CHECK_SIZE_ONLY);
 585         return one->size;
 586 }
 587
 588 static int count_trailing_blank(mmfile_t *mf, unsigned ws_rule)
 589 {
 590         char *ptr = mf->ptr;
 591         long size = mf->size;
 592         int cnt = 0;
 593
 594         if (!size)
 595                 return cnt;
 596         ptr += size - 1; /* pointing at the very end */
 597         if (*ptr != '\n')
 598                 ; /* incomplete line */
 599         else
 600                 ptr--; /* skip the last LF */
 601         while (mf->ptr < ptr) {
 602                 char *prev_eol;
 603                 for (prev_eol = ptr; mf->ptr <= prev_eol; prev_eol--)
 604                         if (*prev_eol == '\n')
 605                                 break;
 606                 if (!ws_blank_line(prev_eol + 1, ptr - prev_eol, ws_rule))
 607                         break;
 608                 cnt++;
 609                 ptr = prev_eol - 1;
 610         }
 611         return cnt;
 612 }
 613
 614 static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
 615                                struct emit_callback *ecbdata)
 616 {
 617         int l1, l2, at;
 618         unsigned ws_rule = ecbdata->ws_rule;
 619         l1 = count_trailing_blank(mf1, ws_rule);
 620         l2 = count_trailing_blank(mf2, ws_rule);
 621         if (l2 <= l1) {
 622                 ecbdata->blank_at_eof_in_preimage = 0;
 623                 ecbdata->blank_at_eof_in_postimage = 0;
 624                 return;
 625         }
 626         at = count_lines(mf1->ptr, mf1->size);
 627         ecbdata->blank_at_eof_in_preimage = (at - l1) + 1;
 628
 629         at = count_lines(mf2->ptr, mf2->size);
 630         ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
 631 }
 632
 633 static void emit_line_0(struct diff_options *o,
 634                         const char *set_sign, const char *set, unsigned reverse, const char *reset,
 635                         int first, const char *line, int len)
 636 {
 637         int has_trailing_newline, has_trailing_carriage_return;
 638         int needs_reset = 0; /* at the end of the line */
 639         FILE *file = o->file;
 640
 641         fputs(diff_line_prefix(o), file);
 642
 643         has_trailing_newline = (len > 0 && line[len-1] == '\n');
 644         if (has_trailing_newline)
 645                 len--;
 646
 647         has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
 648         if (has_trailing_carriage_return)
 649                 len--;
 650
 651         if (!len && !first)
 652                 goto end_of_line;
 653
 654         if (reverse && want_color(o->use_color)) {
 655                 fputs(GIT_COLOR_REVERSE, file);
 656                 needs_reset = 1;
 657         }
 658
 659         if (set_sign) {
 660                 fputs(set_sign, file);
 661                 needs_reset = 1;
 662         }
 663
 664         if (first)
 665                 fputc(first, file);
 666
 667         if (!len)
 668                 goto end_of_line;
 669
 670         if (set) {
 671                 if (set_sign && set != set_sign)
 672                         fputs(reset, file);
 673                 fputs(set, file);
 674                 needs_reset = 1;
 675         }
 676         fwrite(line, len, 1, file);
 677         needs_reset = 1; /* 'line' may contain color codes. */
 678
 679 end_of_line:
 680         if (needs_reset)
 681                 fputs(reset, file);
 682         if (has_trailing_carriage_return)
 683                 fputc('\r', file);
 684         if (has_trailing_newline)
 685                 fputc('\n', file);
 686 }
 687
 688 static void emit_line(struct diff_options *o, const char *set, const char *reset,
 689                       const char *line, int len)
 690 {
 691         emit_line_0(o, set, NULL, 0, reset, 0, line, len);
 692 }
 693
 694 enum diff_symbol {
 695         DIFF_SYMBOL_BINARY_DIFF_HEADER,
 696         DIFF_SYMBOL_BINARY_DIFF_HEADER_DELTA,
 697         DIFF_SYMBOL_BINARY_DIFF_HEADER_LITERAL,
 698         DIFF_SYMBOL_BINARY_DIFF_BODY,
 699         DIFF_SYMBOL_BINARY_DIFF_FOOTER,
 700         DIFF_SYMBOL_STATS_SUMMARY_NO_FILES,
 701         DIFF_SYMBOL_STATS_SUMMARY_ABBREV,
 702         DIFF_SYMBOL_STATS_SUMMARY_INSERTS_DELETES,
 703         DIFF_SYMBOL_STATS_LINE,
 704         DIFF_SYMBOL_WORD_DIFF,
 705         DIFF_SYMBOL_STAT_SEP,
 706         DIFF_SYMBOL_SUMMARY,
 707         DIFF_SYMBOL_SUBMODULE_ADD,
 708         DIFF_SYMBOL_SUBMODULE_DEL,
 709         DIFF_SYMBOL_SUBMODULE_UNTRACKED,
 710         DIFF_SYMBOL_SUBMODULE_MODIFIED,
 711         DIFF_SYMBOL_SUBMODULE_HEADER,
 712         DIFF_SYMBOL_SUBMODULE_ERROR,
 713         DIFF_SYMBOL_SUBMODULE_PIPETHROUGH,
 714         DIFF_SYMBOL_REWRITE_DIFF,
 715         DIFF_SYMBOL_BINARY_FILES,
 716         DIFF_SYMBOL_HEADER,
 717         DIFF_SYMBOL_FILEPAIR_PLUS,
 718         DIFF_SYMBOL_FILEPAIR_MINUS,
 719         DIFF_SYMBOL_WORDS_PORCELAIN,
 720         DIFF_SYMBOL_WORDS,
 721         DIFF_SYMBOL_CONTEXT,
 722         DIFF_SYMBOL_CONTEXT_INCOMPLETE,
 723         DIFF_SYMBOL_PLUS,
 724         DIFF_SYMBOL_MINUS,
 725         DIFF_SYMBOL_NO_LF_EOF,
 726         DIFF_SYMBOL_CONTEXT_FRAGINFO,
 727         DIFF_SYMBOL_CONTEXT_MARKER,
 728         DIFF_SYMBOL_SEPARATOR
 729 };
 730 /*
 731  * Flags for content lines:
 732  * 0..12 are whitespace rules
 733  * 13-15 are WSEH_NEW | WSEH_OLD | WSEH_CONTEXT
 734  * 16 is marking if the line is blank at EOF
 735  */
 736 #define DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF      (1<<16)
 737 #define DIFF_SYMBOL_MOVED_LINE                  (1<<17)
 738 #define DIFF_SYMBOL_MOVED_LINE_ALT              (1<<18)
 739 #define DIFF_SYMBOL_MOVED_LINE_UNINTERESTING    (1<<19)
 740 #define DIFF_SYMBOL_CONTENT_WS_MASK (WSEH_NEW | WSEH_OLD | WSEH_CONTEXT | WS_RULE_MASK)
 741
 742 /*
 743  * This struct is used when we need to buffer the output of the diff output.
 744  *
 745  * NEEDSWORK: Instead of storing a copy of the line, add an offset pointer
 746  * into the pre/post image file. This pointer could be a union with the
 747  * line pointer. By storing an offset into the file instead of the literal line,
 748  * we can decrease the memory footprint for the buffered output. At first we
 749  * may want to only have indirection for the content lines, but we could also
 750  * enhance the state for emitting prefabricated lines, e.g. the similarity
 751  * score line or hunk/file headers would only need to store a number or path
 752  * and then the output can be constructed later on depending on state.
 753  */
 754 struct emitted_diff_symbol {
 755         const char *line;
 756         int len;
 757         int flags;
 758         enum diff_symbol s;
 759 };
 760 #define EMITTED_DIFF_SYMBOL_INIT {NULL}
 761
 762 struct emitted_diff_symbols {
 763         struct emitted_diff_symbol *buf;
 764         int nr, alloc;
 765 };
 766 #define EMITTED_DIFF_SYMBOLS_INIT {NULL, 0, 0}
 767
 768 static void append_emitted_diff_symbol(struct diff_options *o,
 769                                        struct emitted_diff_symbol *e)
 770 {
 771         struct emitted_diff_symbol *f;
 772
 773         ALLOC_GROW(o->emitted_symbols->buf,
 774                    o->emitted_symbols->nr + 1,
 775                    o->emitted_symbols->alloc);
 776         f = &o->emitted_symbols->buf[o->emitted_symbols->nr++];
 777
 778         memcpy(f, e, sizeof(struct emitted_diff_symbol));
 779         f->line = e->line ? xmemdupz(e->line, e->len) : NULL;
 780 }
 781
 782 struct moved_entry {
 783         struct hashmap_entry ent;
 784         const struct emitted_diff_symbol *es;
 785         struct moved_entry *next_line;
 786 };
 787
 788 /**
 789  * The struct ws_delta holds white space differences between moved lines, i.e.
 790  * between '+' and '-' lines that have been detected to be a move.
 791  * The string contains the difference in leading white spaces, before the
 792  * rest of the line is compared using the white space config for move
 793  * coloring. The current_longer indicates if the first string in the
 794  * comparision is longer than the second.
 795  */
 796 struct ws_delta {
 797         char *string;
 798         unsigned int current_longer : 1;
 799 };
 800 #define WS_DELTA_INIT { NULL, 0 }
 801
 802 struct moved_block {
 803         struct moved_entry *match;
 804         struct ws_delta wsd;
 805 };
 806
 807 static void moved_block_clear(struct moved_block *b)
 808 {
 809         FREE_AND_NULL(b->wsd.string);
 810         b->match = NULL;
 811 }
 812
 813 static int compute_ws_delta(const struct emitted_diff_symbol *a,
 814                              const struct emitted_diff_symbol *b,
 815                              struct ws_delta *out)
 816 {
 817         const struct emitted_diff_symbol *longer =  a->len > b->len ? a : b;
 818         const struct emitted_diff_symbol *shorter = a->len > b->len ? b : a;
 819         int d = longer->len - shorter->len;
 820
 821         if (strncmp(longer->line + d, shorter->line, shorter->len))
 822                 return 0;
 823
 824         out->string = xmemdupz(longer->line, d);
 825         out->current_longer = (a == longer);
 826
 827         return 1;
 828 }
 829
 830 static int cmp_in_block_with_wsd(const struct diff_options *o,
 831                                  const struct moved_entry *cur,
 832                                  const struct moved_entry *match,
 833                                  struct moved_block *pmb,
 834                                  int n)
 835 {
 836         struct emitted_diff_symbol *l = &o->emitted_symbols->buf[n];
 837         int al = cur->es->len, cl = l->len;
 838         const char *a = cur->es->line,
 839                    *b = match->es->line,
 840                    *c = l->line;
 841
 842         int wslen;
 843
 844         /*
 845          * We need to check if 'cur' is equal to 'match'.
 846          * As those are from the same (+/-) side, we do not need to adjust for
 847          * indent changes. However these were found using fuzzy matching
 848          * so we do have to check if they are equal.
 849          */
 850         if (strcmp(a, b))
 851                 return 1;
 852
 853         if (!pmb->wsd.string)
 854                 /*
 855                  * The white space delta is not active? This can happen
 856                  * when we exit early in this function.
 857                  */
 858                 return 1;
 859
 860         /*
 861          * The indent changes of the block are known and stored in
 862          * pmb->wsd; however we need to check if the indent changes of the
 863          * current line are still the same as before.
 864          *
 865          * To do so we need to compare 'l' to 'cur', adjusting the
 866          * one of them for the white spaces, depending which was longer.
 867          */
 868
 869         wslen = strlen(pmb->wsd.string);
 870         if (pmb->wsd.current_longer) {
 871                 c += wslen;
 872                 cl -= wslen;
 873         } else {
 874                 a += wslen;
 875                 al -= wslen;
 876         }
 877
 878         if (al != cl || memcmp(a, c, al))
 879                 return 1;
 880
 881         return 0;
 882 }
 883
 884 static int moved_entry_cmp(const void *hashmap_cmp_fn_data,
 885                            const void *entry,
 886                            const void *entry_or_key,
 887                            const void *keydata)
 888 {
 889         const struct diff_options *diffopt = hashmap_cmp_fn_data;
 890         const struct moved_entry *a = entry;
 891         const struct moved_entry *b = entry_or_key;
 892         unsigned flags = diffopt->color_moved_ws_handling
 893                          & XDF_WHITESPACE_FLAGS;
 894
 895         if (diffopt->color_moved_ws_handling &
 896             COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE)
 897                 /*
 898                  * As there is not specific white space config given,
 899                  * we'd need to check for a new block, so ignore all
 900                  * white space. The setup of the white space
 901                  * configuration for the next block is done else where
 902                  */
 903                 flags |= XDF_IGNORE_WHITESPACE;
 904
 905         return !xdiff_compare_lines(a->es->line, a->es->len,
 906                                     b->es->line, b->es->len,
 907                                     flags);
 908 }
 909
 910 static struct moved_entry *prepare_entry(struct diff_options *o,
 911                                          int line_no)
 912 {
 913         struct moved_entry *ret = xmalloc(sizeof(*ret));
 914         struct emitted_diff_symbol *l = &o->emitted_symbols->buf[line_no];
 915         unsigned flags = o->color_moved_ws_handling & XDF_WHITESPACE_FLAGS;
 916
 917         ret->ent.hash = xdiff_hash_string(l->line, l->len, flags);
 918         ret->es = l;
 919         ret->next_line = NULL;
 920
 921         return ret;
 922 }
 923
 924 static void add_lines_to_move_detection(struct diff_options *o,
 925                                         struct hashmap *add_lines,
 926                                         struct hashmap *del_lines)
 927 {
 928         struct moved_entry *prev_line = NULL;
 929
 930         int n;
 931         for (n = 0; n < o->emitted_symbols->nr; n++) {
 932                 struct hashmap *hm;
 933                 struct moved_entry *key;
 934
 935                 switch (o->emitted_symbols->buf[n].s) {
 936                 case DIFF_SYMBOL_PLUS:
 937                         hm = add_lines;
 938                         break;
 939                 case DIFF_SYMBOL_MINUS:
 940                         hm = del_lines;
 941                         break;
 942                 default:
 943                         prev_line = NULL;
 944                         continue;
 945                 }
 946
 947                 key = prepare_entry(o, n);
 948                 if (prev_line && prev_line->es->s == o->emitted_symbols->buf[n].s)
 949                         prev_line->next_line = key;
 950
 951                 hashmap_add(hm, key);
 952                 prev_line = key;
 953         }
 954 }
 955
 956 static void pmb_advance_or_null(struct diff_options *o,
 957                                 struct moved_entry *match,
 958                                 struct hashmap *hm,
 959                                 struct moved_block *pmb,
 960                                 int pmb_nr)
 961 {
 962         int i;
 963         for (i = 0; i < pmb_nr; i++) {
 964                 struct moved_entry *prev = pmb[i].match;
 965                 struct moved_entry *cur = (prev && prev->next_line) ?
 966                                 prev->next_line : NULL;
 967                 if (cur && !hm->cmpfn(o, cur, match, NULL)) {
 968                         pmb[i].match = cur;
 969                 } else {
 970                         pmb[i].match = NULL;
 971                 }
 972         }
 973 }
 974
 975 static void pmb_advance_or_null_multi_match(struct diff_options *o,
 976                                             struct moved_entry *match,
 977                                             struct hashmap *hm,
 978                                             struct moved_block *pmb,
 979                                             int pmb_nr, int n)
 980 {
 981         int i;
 982         char *got_match = xcalloc(1, pmb_nr);
 983
 984         for (; match; match = hashmap_get_next(hm, match)) {
 985                 for (i = 0; i < pmb_nr; i++) {
 986                         struct moved_entry *prev = pmb[i].match;
 987                         struct moved_entry *cur = (prev && prev->next_line) ?
 988                                         prev->next_line : NULL;
 989                         if (!cur)
 990                                 continue;
 991                         if (!cmp_in_block_with_wsd(o, cur, match, &pmb[i], n))
 992                                 got_match[i] |= 1;
 993                 }
 994         }
 995
 996         for (i = 0; i < pmb_nr; i++) {
 997                 if (got_match[i]) {
 998                         /* Advance to the next line */
 999                         pmb[i].match = pmb[i].match->next_line;
1000                 } else {
1001                         moved_block_clear(&pmb[i]);
1002                 }
1003         }
1004
1005         free(got_match);
1006 }
1007
1008 static int shrink_potential_moved_blocks(struct moved_block *pmb,
1009                                          int pmb_nr)
1010 {
1011         int lp, rp;
1012
1013         /* Shrink the set of potential block to the remaining running */
1014         for (lp = 0, rp = pmb_nr - 1; lp <= rp;) {
1015                 while (lp < pmb_nr && pmb[lp].match)
1016                         lp++;
1017                 /* lp points at the first NULL now */
1018
1019                 while (rp > -1 && !pmb[rp].match)
1020                         rp--;
1021                 /* rp points at the last non-NULL */
1022
1023                 if (lp < pmb_nr && rp > -1 && lp < rp) {
1024                         pmb[lp] = pmb[rp];
1025                         pmb[rp].match = NULL;
1026                         pmb[rp].wsd.string = NULL;
1027                         rp--;
1028                         lp++;
1029                 }
1030         }
1031
1032         /* Remember the number of running sets */
1033         return rp + 1;
1034 }
1035
1036 /*
1037  * If o->color_moved is COLOR_MOVED_PLAIN, this function does nothing.
1038  *
1039  * Otherwise, if the last block has fewer alphanumeric characters than
1040  * COLOR_MOVED_MIN_ALNUM_COUNT, unset DIFF_SYMBOL_MOVED_LINE on all lines in
1041  * that block.
1042  *
1043  * The last block consists of the (n - block_length)'th line up to but not
1044  * including the nth line.
1045  *
1046  * NEEDSWORK: This uses the same heuristic as blame_entry_score() in blame.c.
1047  * Think of a way to unify them.
1048  */
1049 static void adjust_last_block(struct diff_options *o, int n, int block_length)
1050 {
1051         int i, alnum_count = 0;
1052         if (o->color_moved == COLOR_MOVED_PLAIN)
1053                 return;
1054         for (i = 1; i < block_length + 1; i++) {
1055                 const char *c = o->emitted_symbols->buf[n - i].line;
1056                 for (; *c; c++) {
1057                         if (!isalnum(*c))
1058                                 continue;
1059                         alnum_count++;
1060                         if (alnum_count >= COLOR_MOVED_MIN_ALNUM_COUNT)
1061                                 return;
1062                 }
1063         }
1064         for (i = 1; i < block_length + 1; i++)
1065                 o->emitted_symbols->buf[n - i].flags &= ~DIFF_SYMBOL_MOVED_LINE;
1066 }
1067
1068 /* Find blocks of moved code, delegate actual coloring decision to helper */
1069 static void mark_color_as_moved(struct diff_options *o,
1070                                 struct hashmap *add_lines,
1071                                 struct hashmap *del_lines)
1072 {
1073         struct moved_block *pmb = NULL; /* potentially moved blocks */
1074         int pmb_nr = 0, pmb_alloc = 0;
1075         int n, flipped_block = 1, block_length = 0;
1076
1077
1078         for (n = 0; n < o->emitted_symbols->nr; n++) {
1079                 struct hashmap *hm = NULL;
1080                 struct moved_entry *key;
1081                 struct moved_entry *match = NULL;
1082                 struct emitted_diff_symbol *l = &o->emitted_symbols->buf[n];
1083
1084                 switch (l->s) {
1085                 case DIFF_SYMBOL_PLUS:
1086                         hm = del_lines;
1087                         key = prepare_entry(o, n);
1088                         match = hashmap_get(hm, key, NULL);
1089                         free(key);
1090                         break;
1091                 case DIFF_SYMBOL_MINUS:
1092                         hm = add_lines;
1093                         key = prepare_entry(o, n);
1094                         match = hashmap_get(hm, key, NULL);
1095                         free(key);
1096                         break;
1097                 default:
1098                         flipped_block = 1;
1099                 }
1100
1101                 if (!match) {
1102                         int i;
1103
1104                         adjust_last_block(o, n, block_length);
1105                         for(i = 0; i < pmb_nr; i++)
1106                                 moved_block_clear(&pmb[i]);
1107                         pmb_nr = 0;
1108                         block_length = 0;
1109                         continue;
1110                 }
1111
1112                 l->flags |= DIFF_SYMBOL_MOVED_LINE;
1113
1114                 if (o->color_moved == COLOR_MOVED_PLAIN)
1115                         continue;
1116
1117                 if (o->color_moved_ws_handling &
1118                     COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE)
1119                         pmb_advance_or_null_multi_match(o, match, hm, pmb, pmb_nr, n);
1120                 else
1121                         pmb_advance_or_null(o, match, hm, pmb, pmb_nr);
1122
1123                 pmb_nr = shrink_potential_moved_blocks(pmb, pmb_nr);
1124
1125                 if (pmb_nr == 0) {
1126                         /*
1127                          * The current line is the start of a new block.
1128                          * Setup the set of potential blocks.
1129                          */
1130                         for (; match; match = hashmap_get_next(hm, match)) {
1131                                 ALLOC_GROW(pmb, pmb_nr + 1, pmb_alloc);
1132                                 if (o->color_moved_ws_handling &
1133                                     COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE) {
1134                                         if (compute_ws_delta(l, match->es,
1135                                                              &pmb[pmb_nr].wsd))
1136                                                 pmb[pmb_nr++].match = match;
1137                                 } else {
1138                                         pmb[pmb_nr].wsd.string = NULL;
1139                                         pmb[pmb_nr++].match = match;
1140                                 }
1141                         }
1142
1143                         flipped_block = (flipped_block + 1) % 2;
1144
1145                         adjust_last_block(o, n, block_length);
1146                         block_length = 0;
1147                 }
1148
1149                 block_length++;
1150
1151                 if (flipped_block && o->color_moved != COLOR_MOVED_BLOCKS)
1152                         l->flags |= DIFF_SYMBOL_MOVED_LINE_ALT;
1153         }
1154         adjust_last_block(o, n, block_length);
1155
1156         for(n = 0; n < pmb_nr; n++)
1157                 moved_block_clear(&pmb[n]);
1158         free(pmb);
1159 }
1160
1161 #define DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK \
1162   (DIFF_SYMBOL_MOVED_LINE | DIFF_SYMBOL_MOVED_LINE_ALT)
1163 static void dim_moved_lines(struct diff_options *o)
1164 {
1165         int n;
1166         for (n = 0; n < o->emitted_symbols->nr; n++) {
1167                 struct emitted_diff_symbol *prev = (n != 0) ?
1168                                 &o->emitted_symbols->buf[n - 1] : NULL;
1169                 struct emitted_diff_symbol *l = &o->emitted_symbols->buf[n];
1170                 struct emitted_diff_symbol *next =
1171                                 (n < o->emitted_symbols->nr - 1) ?
1172                                 &o->emitted_symbols->buf[n + 1] : NULL;
1173
1174                 /* Not a plus or minus line? */
1175                 if (l->s != DIFF_SYMBOL_PLUS && l->s != DIFF_SYMBOL_MINUS)
1176                         continue;
1177
1178                 /* Not a moved line? */
1179                 if (!(l->flags & DIFF_SYMBOL_MOVED_LINE))
1180                         continue;
1181
1182                 /*
1183                  * If prev or next are not a plus or minus line,
1184                  * pretend they don't exist
1185                  */
1186                 if (prev && prev->s != DIFF_SYMBOL_PLUS &&
1187                             prev->s != DIFF_SYMBOL_MINUS)
1188                         prev = NULL;
1189                 if (next && next->s != DIFF_SYMBOL_PLUS &&
1190                             next->s != DIFF_SYMBOL_MINUS)
1191                         next = NULL;
1192
1193                 /* Inside a block? */
1194                 if ((prev &&
1195                     (prev->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK) ==
1196                     (l->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK)) &&
1197                     (next &&
1198                     (next->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK) ==
1199                     (l->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK))) {
1200                         l->flags |= DIFF_SYMBOL_MOVED_LINE_UNINTERESTING;
1201                         continue;
1202                 }
1203
1204                 /* Check if we are at an interesting bound: */
1205                 if (prev && (prev->flags & DIFF_SYMBOL_MOVED_LINE) &&
1206                     (prev->flags & DIFF_SYMBOL_MOVED_LINE_ALT) !=
1207                        (l->flags & DIFF_SYMBOL_MOVED_LINE_ALT))
1208                         continue;
1209                 if (next && (next->flags & DIFF_SYMBOL_MOVED_LINE) &&
1210                     (next->flags & DIFF_SYMBOL_MOVED_LINE_ALT) !=
1211                        (l->flags & DIFF_SYMBOL_MOVED_LINE_ALT))
1212                         continue;
1213
1214                 /*
1215                  * The boundary to prev and next are not interesting,
1216                  * so this line is not interesting as a whole
1217                  */
1218                 l->flags |= DIFF_SYMBOL_MOVED_LINE_UNINTERESTING;
1219         }
1220 }
1221
1222 static void emit_line_ws_markup(struct diff_options *o,
1223                                 const char *set_sign, const char *set,
1224                                 const char *reset,
1225                                 int sign_index, const char *line, int len,
1226                                 unsigned ws_rule, int blank_at_eof)
1227 {
1228         const char *ws = NULL;
1229         int sign = o->output_indicators[sign_index];
1230
1231         if (o->ws_error_highlight & ws_rule) {
1232                 ws = diff_get_color_opt(o, DIFF_WHITESPACE);
1233                 if (!*ws)
1234                         ws = NULL;
1235         }
1236
1237         if (!ws && !set_sign)
1238                 emit_line_0(o, set, NULL, 0, reset, sign, line, len);
1239         else if (!ws) {
1240                 emit_line_0(o, set_sign, set, !!set_sign, reset, sign, line, len);
1241         } else if (blank_at_eof)
1242                 /* Blank line at EOF - paint '+' as well */
1243                 emit_line_0(o, ws, NULL, 0, reset, sign, line, len);
1244         else {
1245                 /* Emit just the prefix, then the rest. */
1246                 emit_line_0(o, set_sign ? set_sign : set, NULL, !!set_sign, reset,
1247                             sign, "", 0);
1248                 ws_check_emit(line, len, ws_rule,
1249                               o->file, set, reset, ws);
1250         }
1251 }
1252
1253 static void emit_diff_symbol_from_struct(struct diff_options *o,
1254                                          struct emitted_diff_symbol *eds)
1255 {
1256         static const char *nneof = " No newline at end of file\n";
1257         const char *context, *reset, *set, *set_sign, *meta, *fraginfo;
1258         struct strbuf sb = STRBUF_INIT;
1259
1260         enum diff_symbol s = eds->s;
1261         const char *line = eds->line;
1262         int len = eds->len;
1263         unsigned flags = eds->flags;
1264
1265         switch (s) {
1266         case DIFF_SYMBOL_NO_LF_EOF:
1267                 context = diff_get_color_opt(o, DIFF_CONTEXT);
1268                 reset = diff_get_color_opt(o, DIFF_RESET);
1269                 putc('\n', o->file);
1270                 emit_line_0(o, context, NULL, 0, reset, '\\',
1271                             nneof, strlen(nneof));
1272                 break;
1273         case DIFF_SYMBOL_SUBMODULE_HEADER:
1274         case DIFF_SYMBOL_SUBMODULE_ERROR:
1275         case DIFF_SYMBOL_SUBMODULE_PIPETHROUGH:
1276         case DIFF_SYMBOL_STATS_SUMMARY_INSERTS_DELETES:
1277         case DIFF_SYMBOL_SUMMARY:
1278         case DIFF_SYMBOL_STATS_LINE:
1279         case DIFF_SYMBOL_BINARY_DIFF_BODY:
1280         case DIFF_SYMBOL_CONTEXT_FRAGINFO:
1281                 emit_line(o, "", "", line, len);
1282                 break;
1283         case DIFF_SYMBOL_CONTEXT_INCOMPLETE:
1284         case DIFF_SYMBOL_CONTEXT_MARKER:
1285                 context = diff_get_color_opt(o, DIFF_CONTEXT);
1286                 reset = diff_get_color_opt(o, DIFF_RESET);
1287                 emit_line(o, context, reset, line, len);
1288                 break;
1289         case DIFF_SYMBOL_SEPARATOR:
1290                 fprintf(o->file, "%s%c",
1291                         diff_line_prefix(o),
1292                         o->line_termination);
1293                 break;
1294         case DIFF_SYMBOL_CONTEXT:
1295                 set = diff_get_color_opt(o, DIFF_CONTEXT);
1296                 reset = diff_get_color_opt(o, DIFF_RESET);
1297                 set_sign = NULL;
1298                 if (o->flags.dual_color_diffed_diffs) {
1299                         char c = !len ? 0 : line[0];
1300
1301                         if (c == '+')
1302                                 set = diff_get_color_opt(o, DIFF_FILE_NEW);
1303                         else if (c == '@')
1304                                 set = diff_get_color_opt(o, DIFF_FRAGINFO);
1305                         else if (c == '-')
1306                                 set = diff_get_color_opt(o, DIFF_FILE_OLD);
1307                 }
1308                 emit_line_ws_markup(o, set_sign, set, reset,
1309                                     OUTPUT_INDICATOR_CONTEXT, line, len,
1310                                     flags & (DIFF_SYMBOL_CONTENT_WS_MASK), 0);
1311                 break;
1312         case DIFF_SYMBOL_PLUS:
1313                 switch (flags & (DIFF_SYMBOL_MOVED_LINE |
1314                                  DIFF_SYMBOL_MOVED_LINE_ALT |
1315                                  DIFF_SYMBOL_MOVED_LINE_UNINTERESTING)) {
1316                 case DIFF_SYMBOL_MOVED_LINE |
1317                      DIFF_SYMBOL_MOVED_LINE_ALT |
1318                      DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1319                         set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED_ALT_DIM);
1320                         break;
1321                 case DIFF_SYMBOL_MOVED_LINE |
1322                      DIFF_SYMBOL_MOVED_LINE_ALT:
1323                         set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED_ALT);
1324                         break;
1325                 case DIFF_SYMBOL_MOVED_LINE |
1326                      DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1327                         set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED_DIM);
1328                         break;
1329                 case DIFF_SYMBOL_MOVED_LINE:
1330                         set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED);
1331                         break;
1332                 default:
1333                         set = diff_get_color_opt(o, DIFF_FILE_NEW);
1334                 }
1335                 reset = diff_get_color_opt(o, DIFF_RESET);
1336                 if (!o->flags.dual_color_diffed_diffs)
1337                         set_sign = NULL;
1338                 else {
1339                         char c = !len ? 0 : line[0];
1340
1341                         set_sign = set;
1342                         if (c == '-')
1343                                 set = diff_get_color_opt(o, DIFF_FILE_OLD_BOLD);
1344                         else if (c == '@')
1345                                 set = diff_get_color_opt(o, DIFF_FRAGINFO);
1346                         else if (c == '+')
1347                                 set = diff_get_color_opt(o, DIFF_FILE_NEW_BOLD);
1348                         else
1349                                 set = diff_get_color_opt(o, DIFF_CONTEXT_BOLD);
1350                         flags &= ~DIFF_SYMBOL_CONTENT_WS_MASK;
1351                 }
1352                 emit_line_ws_markup(o, set_sign, set, reset,
1353                                     OUTPUT_INDICATOR_NEW, line, len,
1354                                     flags & DIFF_SYMBOL_CONTENT_WS_MASK,
1355                                     flags & DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF);
1356                 break;
1357         case DIFF_SYMBOL_MINUS:
1358                 switch (flags & (DIFF_SYMBOL_MOVED_LINE |
1359                                  DIFF_SYMBOL_MOVED_LINE_ALT |
1360                                  DIFF_SYMBOL_MOVED_LINE_UNINTERESTING)) {
1361                 case DIFF_SYMBOL_MOVED_LINE |
1362                      DIFF_SYMBOL_MOVED_LINE_ALT |
1363                      DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1364                         set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED_ALT_DIM);
1365                         break;
1366                 case DIFF_SYMBOL_MOVED_LINE |
1367                      DIFF_SYMBOL_MOVED_LINE_ALT:
1368                         set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED_ALT);
1369                         break;
1370                 case DIFF_SYMBOL_MOVED_LINE |
1371                      DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1372                         set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED_DIM);
1373                         break;
1374                 case DIFF_SYMBOL_MOVED_LINE:
1375                         set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED);
1376                         break;
1377                 default:
1378                         set = diff_get_color_opt(o, DIFF_FILE_OLD);
1379                 }
1380                 reset = diff_get_color_opt(o, DIFF_RESET);
1381                 if (!o->flags.dual_color_diffed_diffs)
1382                         set_sign = NULL;
1383                 else {
1384                         char c = !len ? 0 : line[0];
1385
1386                         set_sign = set;
1387                         if (c == '+')
1388                                 set = diff_get_color_opt(o, DIFF_FILE_NEW_DIM);
1389                         else if (c == '@')
1390                                 set = diff_get_color_opt(o, DIFF_FRAGINFO);
1391                         else if (c == '-')
1392                                 set = diff_get_color_opt(o, DIFF_FILE_OLD_DIM);
1393                         else
1394                                 set = diff_get_color_opt(o, DIFF_CONTEXT_DIM);
1395                 }
1396                 emit_line_ws_markup(o, set_sign, set, reset,
1397                                     OUTPUT_INDICATOR_OLD, line, len,
1398                                     flags & DIFF_SYMBOL_CONTENT_WS_MASK, 0);
1399                 break;
1400         case DIFF_SYMBOL_WORDS_PORCELAIN:
1401                 context = diff_get_color_opt(o, DIFF_CONTEXT);
1402                 reset = diff_get_color_opt(o, DIFF_RESET);
1403                 emit_line(o, context, reset, line, len);
1404                 fputs("~\n", o->file);
1405                 break;
1406         case DIFF_SYMBOL_WORDS:
1407                 context = diff_get_color_opt(o, DIFF_CONTEXT);
1408                 reset = diff_get_color_opt(o, DIFF_RESET);
1409                 /*
1410                  * Skip the prefix character, if any.  With
1411                  * diff_suppress_blank_empty, there may be
1412                  * none.
1413                  */
1414                 if (line[0] != '\n') {
1415                         line++;
1416                         len--;
1417                 }
1418                 emit_line(o, context, reset, line, len);
1419                 break;
1420         case DIFF_SYMBOL_FILEPAIR_PLUS:
1421                 meta = diff_get_color_opt(o, DIFF_METAINFO);
1422                 reset = diff_get_color_opt(o, DIFF_RESET);
1423                 fprintf(o->file, "%s%s+++ %s%s%s\n", diff_line_prefix(o), meta,
1424                         line, reset,
1425                         strchr(line, ' ') ? "\t" : "");
1426                 break;
1427         case DIFF_SYMBOL_FILEPAIR_MINUS:
1428                 meta = diff_get_color_opt(o, DIFF_METAINFO);
1429                 reset = diff_get_color_opt(o, DIFF_RESET);
1430                 fprintf(o->file, "%s%s--- %s%s%s\n", diff_line_prefix(o), meta,
1431                         line, reset,
1432                         strchr(line, ' ') ? "\t" : "");
1433                 break;
1434         case DIFF_SYMBOL_BINARY_FILES:
1435         case DIFF_SYMBOL_HEADER:
1436                 fprintf(o->file, "%s", line);
1437                 break;
1438         case DIFF_SYMBOL_BINARY_DIFF_HEADER:
1439                 fprintf(o->file, "%sGIT binary patch\n", diff_line_prefix(o));
1440                 break;
1441         case DIFF_SYMBOL_BINARY_DIFF_HEADER_DELTA:
1442                 fprintf(o->file, "%sdelta %s\n", diff_line_prefix(o), line);
1443                 break;
1444         case DIFF_SYMBOL_BINARY_DIFF_HEADER_LITERAL:
1445                 fprintf(o->file, "%sliteral %s\n", diff_line_prefix(o), line);
1446                 break;
1447         case DIFF_SYMBOL_BINARY_DIFF_FOOTER:
1448                 fputs(diff_line_prefix(o), o->file);
1449                 fputc('\n', o->file);
1450                 break;
1451         case DIFF_SYMBOL_REWRITE_DIFF:
1452                 fraginfo = diff_get_color(o->use_color, DIFF_FRAGINFO);
1453                 reset = diff_get_color_opt(o, DIFF_RESET);
1454                 emit_line(o, fraginfo, reset, line, len);
1455                 break;
1456         case DIFF_SYMBOL_SUBMODULE_ADD:
1457                 set = diff_get_color_opt(o, DIFF_FILE_NEW);
1458                 reset = diff_get_color_opt(o, DIFF_RESET);
1459                 emit_line(o, set, reset, line, len);
1460                 break;
1461         case DIFF_SYMBOL_SUBMODULE_DEL:
1462                 set = diff_get_color_opt(o, DIFF_FILE_OLD);
1463                 reset = diff_get_color_opt(o, DIFF_RESET);
1464                 emit_line(o, set, reset, line, len);
1465                 break;
1466         case DIFF_SYMBOL_SUBMODULE_UNTRACKED:
1467                 fprintf(o->file, "%sSubmodule %s contains untracked content\n",
1468                         diff_line_prefix(o), line);
1469                 break;
1470         case DIFF_SYMBOL_SUBMODULE_MODIFIED:
1471                 fprintf(o->file, "%sSubmodule %s contains modified content\n",
1472                         diff_line_prefix(o), line);
1473                 break;
1474         case DIFF_SYMBOL_STATS_SUMMARY_NO_FILES:
1475                 emit_line(o, "", "", " 0 files changed\n",
1476                           strlen(" 0 files changed\n"));
1477                 break;
1478         case DIFF_SYMBOL_STATS_SUMMARY_ABBREV:
1479                 emit_line(o, "", "", " ...\n", strlen(" ...\n"));
1480                 break;
1481         case DIFF_SYMBOL_WORD_DIFF:
1482                 fprintf(o->file, "%.*s", len, line);
1483                 break;
1484         case DIFF_SYMBOL_STAT_SEP:
1485                 fputs(o->stat_sep, o->file);
1486                 break;
1487         default:
1488                 BUG("unknown diff symbol");
1489         }
1490         strbuf_release(&sb);
1491 }
1492
1493 static void emit_diff_symbol(struct diff_options *o, enum diff_symbol s,
1494                              const char *line, int len, unsigned flags)
1495 {
1496         struct emitted_diff_symbol e = {line, len, flags, s};
1497
1498         if (o->emitted_symbols)
1499                 append_emitted_diff_symbol(o, &e);
1500         else
1501                 emit_diff_symbol_from_struct(o, &e);
1502 }
1503
1504 void diff_emit_submodule_del(struct diff_options *o, const char *line)
1505 {
1506         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_DEL, line, strlen(line), 0);
1507 }
1508
1509 void diff_emit_submodule_add(struct diff_options *o, const char *line)
1510 {
1511         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_ADD, line, strlen(line), 0);
1512 }
1513
1514 void diff_emit_submodule_untracked(struct diff_options *o, const char *path)
1515 {
1516         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_UNTRACKED,
1517                          path, strlen(path), 0);
1518 }
1519
1520 void diff_emit_submodule_modified(struct diff_options *o, const char *path)
1521 {
1522         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_MODIFIED,
1523                          path, strlen(path), 0);
1524 }
1525
1526 void diff_emit_submodule_header(struct diff_options *o, const char *header)
1527 {
1528         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_HEADER,
1529                          header, strlen(header), 0);
1530 }
1531
1532 void diff_emit_submodule_error(struct diff_options *o, const char *err)
1533 {
1534         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_ERROR, err, strlen(err), 0);
1535 }
1536
1537 void diff_emit_submodule_pipethrough(struct diff_options *o,
1538                                      const char *line, int len)
1539 {
1540         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_PIPETHROUGH, line, len, 0);
1541 }
1542
1543 static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
1544 {
1545         if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
1546               ecbdata->blank_at_eof_in_preimage &&
1547               ecbdata->blank_at_eof_in_postimage &&
1548               ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
1549               ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
1550                 return 0;
1551         return ws_blank_line(line, len, ecbdata->ws_rule);
1552 }
1553
1554 static void emit_add_line(const char *reset,
1555                           struct emit_callback *ecbdata,
1556                           const char *line, int len)
1557 {
1558         unsigned flags = WSEH_NEW | ecbdata->ws_rule;
1559         if (new_blank_line_at_eof(ecbdata, line, len))
1560                 flags |= DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF;
1561
1562         emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_PLUS, line, len, flags);
1563 }
1564
1565 static void emit_del_line(const char *reset,
1566                           struct emit_callback *ecbdata,
1567                           const char *line, int len)
1568 {
1569         unsigned flags = WSEH_OLD | ecbdata->ws_rule;
1570         emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_MINUS, line, len, flags);
1571 }
1572
1573 static void emit_context_line(const char *reset,
1574                               struct emit_callback *ecbdata,
1575                               const char *line, int len)
1576 {
1577         unsigned flags = WSEH_CONTEXT | ecbdata->ws_rule;
1578         emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_CONTEXT, line, len, flags);
1579 }
1580
1581 static void emit_hunk_header(struct emit_callback *ecbdata,
1582                              const char *line, int len)
1583 {
1584         const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
1585         const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
1586         const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
1587         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1588         const char *reverse = ecbdata->color_diff ? GIT_COLOR_REVERSE : "";
1589         static const char atat[2] = { '@', '@' };
1590         const char *cp, *ep;
1591         struct strbuf msgbuf = STRBUF_INIT;
1592         int org_len = len;
1593         int i = 1;
1594
1595         /*
1596          * As a hunk header must begin with "@@ -<old>, +<new> @@",
1597          * it always is at least 10 bytes long.
1598          */
1599         if (len < 10 ||
1600             memcmp(line, atat, 2) ||
1601             !(ep = memmem(line + 2, len - 2, atat, 2))) {
1602                 emit_diff_symbol(ecbdata->opt,
1603                                  DIFF_SYMBOL_CONTEXT_MARKER, line, len, 0);
1604                 return;
1605         }
1606         ep += 2; /* skip over @@ */
1607
1608         /* The hunk header in fraginfo color */
1609         if (ecbdata->opt->flags.dual_color_diffed_diffs)
1610                 strbuf_addstr(&msgbuf, reverse);
1611         strbuf_addstr(&msgbuf, frag);
1612         strbuf_add(&msgbuf, line, ep - line);
1613         strbuf_addstr(&msgbuf, reset);
1614
1615         /*
1616          * trailing "\r\n"
1617          */
1618         for ( ; i < 3; i++)
1619                 if (line[len - i] == '\r' || line[len - i] == '\n')
1620                         len--;
1621
1622         /* blank before the func header */
1623         for (cp = ep; ep - line < len; ep++)
1624                 if (*ep != ' ' && *ep != '\t')
1625                         break;
1626         if (ep != cp) {
1627                 strbuf_addstr(&msgbuf, context);
1628                 strbuf_add(&msgbuf, cp, ep - cp);
1629                 strbuf_addstr(&msgbuf, reset);
1630         }
1631
1632         if (ep < line + len) {
1633                 strbuf_addstr(&msgbuf, func);
1634                 strbuf_add(&msgbuf, ep, line + len - ep);
1635                 strbuf_addstr(&msgbuf, reset);
1636         }
1637
1638         strbuf_add(&msgbuf, line + len, org_len - len);
1639         strbuf_complete_line(&msgbuf);
1640         emit_diff_symbol(ecbdata->opt,
1641                          DIFF_SYMBOL_CONTEXT_FRAGINFO, msgbuf.buf, msgbuf.len, 0);
1642         strbuf_release(&msgbuf);
1643 }
1644
1645 static struct diff_tempfile *claim_diff_tempfile(void)
1646 {
1647         int i;
1648         for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
1649                 if (!diff_temp[i].name)
1650                         return diff_temp + i;
1651         BUG("diff is failing to clean up its tempfiles");
1652 }
1653
1654 static void remove_tempfile(void)
1655 {
1656         int i;
1657         for (i = 0; i < ARRAY_SIZE(diff_temp); i++) {
1658                 if (is_tempfile_active(diff_temp[i].tempfile))
1659                         delete_tempfile(&diff_temp[i].tempfile);
1660                 diff_temp[i].name = NULL;
1661         }
1662 }
1663
1664 static void add_line_count(struct strbuf *out, int count)
1665 {
1666         switch (count) {
1667         case 0:
1668                 strbuf_addstr(out, "0,0");
1669                 break;
1670         case 1:
1671                 strbuf_addstr(out, "1");
1672                 break;
1673         default:
1674                 strbuf_addf(out, "1,%d", count);
1675                 break;
1676         }
1677 }
1678
1679 static void emit_rewrite_lines(struct emit_callback *ecb,
1680                                int prefix, const char *data, int size)
1681 {
1682         const char *endp = NULL;
1683         const char *reset = diff_get_color(ecb->color_diff, DIFF_RESET);
1684
1685         while (0 < size) {
1686                 int len;
1687
1688                 endp = memchr(data, '\n', size);
1689                 len = endp ? (endp - data + 1) : size;
1690                 if (prefix != '+') {
1691                         ecb->lno_in_preimage++;
1692                         emit_del_line(reset, ecb, data, len);
1693                 } else {
1694                         ecb->lno_in_postimage++;
1695                         emit_add_line(reset, ecb, data, len);
1696                 }
1697                 size -= len;
1698                 data += len;
1699         }
1700         if (!endp)
1701                 emit_diff_symbol(ecb->opt, DIFF_SYMBOL_NO_LF_EOF, NULL, 0, 0);
1702 }
1703
1704 static void emit_rewrite_diff(const char *name_a,
1705                               const char *name_b,
1706                               struct diff_filespec *one,
1707                               struct diff_filespec *two,
1708                               struct userdiff_driver *textconv_one,
1709                               struct userdiff_driver *textconv_two,
1710                               struct diff_options *o)
1711 {
1712         int lc_a, lc_b;
1713         static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
1714         const char *a_prefix, *b_prefix;
1715         char *data_one, *data_two;
1716         size_t size_one, size_two;
1717         struct emit_callback ecbdata;
1718         struct strbuf out = STRBUF_INIT;
1719
1720         if (diff_mnemonic_prefix && o->flags.reverse_diff) {
1721                 a_prefix = o->b_prefix;
1722                 b_prefix = o->a_prefix;
1723         } else {
1724                 a_prefix = o->a_prefix;
1725                 b_prefix = o->b_prefix;
1726         }
1727
1728         name_a += (*name_a == '/');
1729         name_b += (*name_b == '/');
1730
1731         strbuf_reset(&a_name);
1732         strbuf_reset(&b_name);
1733         quote_two_c_style(&a_name, a_prefix, name_a, 0);
1734         quote_two_c_style(&b_name, b_prefix, name_b, 0);
1735
1736         size_one = fill_textconv(o->repo, textconv_one, one, &data_one);
1737         size_two = fill_textconv(o->repo, textconv_two, two, &data_two);
1738
1739         memset(&ecbdata, 0, sizeof(ecbdata));
1740         ecbdata.color_diff = want_color(o->use_color);
1741         ecbdata.ws_rule = whitespace_rule(o->repo->index, name_b);
1742         ecbdata.opt = o;
1743         if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
1744                 mmfile_t mf1, mf2;
1745                 mf1.ptr = (char *)data_one;
1746                 mf2.ptr = (char *)data_two;
1747                 mf1.size = size_one;
1748                 mf2.size = size_two;
1749                 check_blank_at_eof(&mf1, &mf2, &ecbdata);
1750         }
1751         ecbdata.lno_in_preimage = 1;
1752         ecbdata.lno_in_postimage = 1;
1753
1754         lc_a = count_lines(data_one, size_one);
1755         lc_b = count_lines(data_two, size_two);
1756
1757         emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_MINUS,
1758                          a_name.buf, a_name.len, 0);
1759         emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_PLUS,
1760                          b_name.buf, b_name.len, 0);
1761
1762         strbuf_addstr(&out, "@@ -");
1763         if (!o->irreversible_delete)
1764                 add_line_count(&out, lc_a);
1765         else
1766                 strbuf_addstr(&out, "?,?");
1767         strbuf_addstr(&out, " +");
1768         add_line_count(&out, lc_b);
1769         strbuf_addstr(&out, " @@\n");
1770         emit_diff_symbol(o, DIFF_SYMBOL_REWRITE_DIFF, out.buf, out.len, 0);
1771         strbuf_release(&out);
1772
1773         if (lc_a && !o->irreversible_delete)
1774                 emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
1775         if (lc_b)
1776                 emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
1777         if (textconv_one)
1778                 free((char *)data_one);
1779         if (textconv_two)
1780                 free((char *)data_two);
1781 }
1782
1783 struct diff_words_buffer {
1784         mmfile_t text;
1785         unsigned long alloc;
1786         struct diff_words_orig {
1787                 const char *begin, *end;
1788         } *orig;
1789         int orig_nr, orig_alloc;
1790 };
1791
1792 static void diff_words_append(char *line, unsigned long len,
1793                 struct diff_words_buffer *buffer)
1794 {
1795         ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
1796         line++;
1797         len--;
1798         memcpy(buffer->text.ptr + buffer->text.size, line, len);
1799         buffer->text.size += len;
1800         buffer->text.ptr[buffer->text.size] = '\0';
1801 }
1802
1803 struct diff_words_style_elem {
1804         const char *prefix;
1805         const char *suffix;
1806         const char *color; /* NULL; filled in by the setup code if
1807                             * color is enabled */
1808 };
1809
1810 struct diff_words_style {
1811         enum diff_words_type type;
1812         struct diff_words_style_elem new_word, old_word, ctx;
1813         const char *newline;
1814 };
1815
1816 static struct diff_words_style diff_words_styles[] = {
1817         { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
1818         { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
1819         { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
1820 };
1821
1822 struct diff_words_data {
1823         struct diff_words_buffer minus, plus;
1824         const char *current_plus;
1825         int last_minus;
1826         struct diff_options *opt;
1827         regex_t *word_regex;
1828         enum diff_words_type type;
1829         struct diff_words_style *style;
1830 };
1831
1832 static int fn_out_diff_words_write_helper(struct diff_options *o,
1833                                           struct diff_words_style_elem *st_el,
1834                                           const char *newline,
1835                                           size_t count, const char *buf)
1836 {
1837         int print = 0;
1838         struct strbuf sb = STRBUF_INIT;
1839
1840         while (count) {
1841                 char *p = memchr(buf, '\n', count);
1842                 if (print)
1843                         strbuf_addstr(&sb, diff_line_prefix(o));
1844
1845                 if (p != buf) {
1846                         const char *reset = st_el->color && *st_el->color ?
1847                                             GIT_COLOR_RESET : NULL;
1848                         if (st_el->color && *st_el->color)
1849                                 strbuf_addstr(&sb, st_el->color);
1850                         strbuf_addstr(&sb, st_el->prefix);
1851                         strbuf_add(&sb, buf, p ? p - buf : count);
1852                         strbuf_addstr(&sb, st_el->suffix);
1853                         if (reset)
1854                                 strbuf_addstr(&sb, reset);
1855                 }
1856                 if (!p)
1857                         goto out;
1858
1859                 strbuf_addstr(&sb, newline);
1860                 count -= p + 1 - buf;
1861                 buf = p + 1;
1862                 print = 1;
1863                 if (count) {
1864                         emit_diff_symbol(o, DIFF_SYMBOL_WORD_DIFF,
1865                                          sb.buf, sb.len, 0);
1866                         strbuf_reset(&sb);
1867                 }
1868         }
1869
1870 out:
1871         if (sb.len)
1872                 emit_diff_symbol(o, DIFF_SYMBOL_WORD_DIFF,
1873                                  sb.buf, sb.len, 0);
1874         strbuf_release(&sb);
1875         return 0;
1876 }
1877
1878 /*
1879  * '--color-words' algorithm can be described as:
1880  *
1881  *   1. collect the minus/plus lines of a diff hunk, divided into
1882  *      minus-lines and plus-lines;
1883  *
1884  *   2. break both minus-lines and plus-lines into words and
1885  *      place them into two mmfile_t with one word for each line;
1886  *
1887  *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
1888  *
1889  * And for the common parts of the both file, we output the plus side text.
1890  * diff_words->current_plus is used to trace the current position of the plus file
1891  * which printed. diff_words->last_minus is used to trace the last minus word
1892  * printed.
1893  *
1894  * For '--graph' to work with '--color-words', we need to output the graph prefix
1895  * on each line of color words output. Generally, there are two conditions on
1896  * which we should output the prefix.
1897  *
1898  *   1. diff_words->last_minus == 0 &&
1899  *      diff_words->current_plus == diff_words->plus.text.ptr
1900  *
1901  *      that is: the plus text must start as a new line, and if there is no minus
1902  *      word printed, a graph prefix must be printed.
1903  *
1904  *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
1905  *      *(diff_words->current_plus - 1) == '\n'
1906  *
1907  *      that is: a graph prefix must be printed following a '\n'
1908  */
1909 static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
1910 {
1911         if ((diff_words->last_minus == 0 &&
1912                 diff_words->current_plus == diff_words->plus.text.ptr) ||
1913                 (diff_words->current_plus > diff_words->plus.text.ptr &&
1914                 *(diff_words->current_plus - 1) == '\n')) {
1915                 return 1;
1916         } else {
1917                 return 0;
1918         }
1919 }
1920
1921 static void fn_out_diff_words_aux(void *priv,
1922                                   long minus_first, long minus_len,
1923                                   long plus_first, long plus_len,
1924                                   const char *func, long funclen)
1925 {
1926         struct diff_words_data *diff_words = priv;
1927         struct diff_words_style *style = diff_words->style;
1928         const char *minus_begin, *minus_end, *plus_begin, *plus_end;
1929         struct diff_options *opt = diff_words->opt;
1930         const char *line_prefix;
1931
1932         assert(opt);
1933         line_prefix = diff_line_prefix(opt);
1934
1935         /* POSIX requires that first be decremented by one if len == 0... */
1936         if (minus_len) {
1937                 minus_begin = diff_words->minus.orig[minus_first].begin;
1938                 minus_end =
1939                         diff_words->minus.orig[minus_first + minus_len - 1].end;
1940         } else
1941                 minus_begin = minus_end =
1942                         diff_words->minus.orig[minus_first].end;
1943
1944         if (plus_len) {
1945                 plus_begin = diff_words->plus.orig[plus_first].begin;
1946                 plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
1947         } else
1948                 plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
1949
1950         if (color_words_output_graph_prefix(diff_words)) {
1951                 fputs(line_prefix, diff_words->opt->file);
1952         }
1953         if (diff_words->current_plus != plus_begin) {
1954                 fn_out_diff_words_write_helper(diff_words->opt,
1955                                 &style->ctx, style->newline,
1956                                 plus_begin - diff_words->current_plus,
1957                                 diff_words->current_plus);
1958         }
1959         if (minus_begin != minus_end) {
1960                 fn_out_diff_words_write_helper(diff_words->opt,
1961                                 &style->old_word, style->newline,
1962                                 minus_end - minus_begin, minus_begin);
1963         }
1964         if (plus_begin != plus_end) {
1965                 fn_out_diff_words_write_helper(diff_words->opt,
1966                                 &style->new_word, style->newline,
1967                                 plus_end - plus_begin, plus_begin);
1968         }
1969
1970         diff_words->current_plus = plus_end;
1971         diff_words->last_minus = minus_first;
1972 }
1973
1974 /* This function starts looking at *begin, and returns 0 iff a word was found. */
1975 static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
1976                 int *begin, int *end)
1977 {
1978         if (word_regex && *begin < buffer->size) {
1979                 regmatch_t match[1];
1980                 if (!regexec_buf(word_regex, buffer->ptr + *begin,
1981                                  buffer->size - *begin, 1, match, 0)) {
1982                         char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
1983                                         '\n', match[0].rm_eo - match[0].rm_so);
1984                         *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
1985                         *begin += match[0].rm_so;
1986                         return *begin >= *end;
1987                 }
1988                 return -1;
1989         }
1990
1991         /* find the next word */
1992         while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
1993                 (*begin)++;
1994         if (*begin >= buffer->size)
1995                 return -1;
1996
1997         /* find the end of the word */
1998         *end = *begin + 1;
1999         while (*end < buffer->size && !isspace(buffer->ptr[*end]))
2000                 (*end)++;
2001
2002         return 0;
2003 }
2004
2005 /*
2006  * This function splits the words in buffer->text, stores the list with
2007  * newline separator into out, and saves the offsets of the original words
2008  * in buffer->orig.
2009  */
2010 static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
2011                 regex_t *word_regex)
2012 {
2013         int i, j;
2014         long alloc = 0;
2015
2016         out->size = 0;
2017         out->ptr = NULL;
2018
2019         /* fake an empty "0th" word */
2020         ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
2021         buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
2022         buffer->orig_nr = 1;
2023
2024         for (i = 0; i < buffer->text.size; i++) {
2025                 if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
2026                         return;
2027
2028                 /* store original boundaries */
2029                 ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
2030                                 buffer->orig_alloc);
2031                 buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
2032                 buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
2033                 buffer->orig_nr++;
2034
2035                 /* store one word */
2036                 ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
2037                 memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
2038                 out->ptr[out->size + j - i] = '\n';
2039                 out->size += j - i + 1;
2040
2041                 i = j - 1;
2042         }
2043 }
2044
2045 /* this executes the word diff on the accumulated buffers */
2046 static void diff_words_show(struct diff_words_data *diff_words)
2047 {
2048         xpparam_t xpp;
2049         xdemitconf_t xecfg;
2050         mmfile_t minus, plus;
2051         struct diff_words_style *style = diff_words->style;
2052
2053         struct diff_options *opt = diff_words->opt;
2054         const char *line_prefix;
2055
2056         assert(opt);
2057         line_prefix = diff_line_prefix(opt);
2058
2059         /* special case: only removal */
2060         if (!diff_words->plus.text.size) {
2061                 emit_diff_symbol(diff_words->opt, DIFF_SYMBOL_WORD_DIFF,
2062                                  line_prefix, strlen(line_prefix), 0);
2063                 fn_out_diff_words_write_helper(diff_words->opt,
2064                         &style->old_word, style->newline,
2065                         diff_words->minus.text.size,
2066                         diff_words->minus.text.ptr);
2067                 diff_words->minus.text.size = 0;
2068                 return;
2069         }
2070
2071         diff_words->current_plus = diff_words->plus.text.ptr;
2072         diff_words->last_minus = 0;
2073
2074         memset(&xpp, 0, sizeof(xpp));
2075         memset(&xecfg, 0, sizeof(xecfg));
2076         diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
2077         diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
2078         xpp.flags = 0;
2079         /* as only the hunk header will be parsed, we need a 0-context */
2080         xecfg.ctxlen = 0;
2081         if (xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, NULL,
2082                           diff_words, &xpp, &xecfg))
2083                 die("unable to generate word diff");
2084         free(minus.ptr);
2085         free(plus.ptr);
2086         if (diff_words->current_plus != diff_words->plus.text.ptr +
2087                         diff_words->plus.text.size) {
2088                 if (color_words_output_graph_prefix(diff_words))
2089                         emit_diff_symbol(diff_words->opt, DIFF_SYMBOL_WORD_DIFF,
2090                                          line_prefix, strlen(line_prefix), 0);
2091                 fn_out_diff_words_write_helper(diff_words->opt,
2092                         &style->ctx, style->newline,
2093                         diff_words->plus.text.ptr + diff_words->plus.text.size
2094                         - diff_words->current_plus, diff_words->current_plus);
2095         }
2096         diff_words->minus.text.size = diff_words->plus.text.size = 0;
2097 }
2098
2099 /* In "color-words" mode, show word-diff of words accumulated in the buffer */
2100 static void diff_words_flush(struct emit_callback *ecbdata)
2101 {
2102         struct diff_options *wo = ecbdata->diff_words->opt;
2103
2104         if (ecbdata->diff_words->minus.text.size ||
2105             ecbdata->diff_words->plus.text.size)
2106                 diff_words_show(ecbdata->diff_words);
2107
2108         if (wo->emitted_symbols) {
2109                 struct diff_options *o = ecbdata->opt;
2110                 struct emitted_diff_symbols *wol = wo->emitted_symbols;
2111                 int i;
2112
2113                 /*
2114                  * NEEDSWORK:
2115                  * Instead of appending each, concat all words to a line?
2116                  */
2117                 for (i = 0; i < wol->nr; i++)
2118                         append_emitted_diff_symbol(o, &wol->buf[i]);
2119
2120                 for (i = 0; i < wol->nr; i++)
2121                         free((void *)wol->buf[i].line);
2122
2123                 wol->nr = 0;
2124         }
2125 }
2126
2127 static void diff_filespec_load_driver(struct diff_filespec *one,
2128                                       struct index_state *istate)
2129 {
2130         /* Use already-loaded driver */
2131         if (one->driver)
2132                 return;
2133
2134         if (S_ISREG(one->mode))
2135                 one->driver = userdiff_find_by_path(istate, one->path);
2136
2137         /* Fallback to default settings */
2138         if (!one->driver)
2139                 one->driver = userdiff_find_by_name("default");
2140 }
2141
2142 static const char *userdiff_word_regex(struct diff_filespec *one,
2143                                        struct index_state *istate)
2144 {
2145         diff_filespec_load_driver(one, istate);
2146         return one->driver->word_regex;
2147 }
2148
2149 static void init_diff_words_data(struct emit_callback *ecbdata,
2150                                  struct diff_options *orig_opts,
2151                                  struct diff_filespec *one,
2152                                  struct diff_filespec *two)
2153 {
2154         int i;
2155         struct diff_options *o = xmalloc(sizeof(struct diff_options));
2156         memcpy(o, orig_opts, sizeof(struct diff_options));
2157
2158         ecbdata->diff_words =
2159                 xcalloc(1, sizeof(struct diff_words_data));
2160         ecbdata->diff_words->type = o->word_diff;
2161         ecbdata->diff_words->opt = o;
2162
2163         if (orig_opts->emitted_symbols)
2164                 o->emitted_symbols =
2165                         xcalloc(1, sizeof(struct emitted_diff_symbols));
2166
2167         if (!o->word_regex)
2168                 o->word_regex = userdiff_word_regex(one, o->repo->index);
2169         if (!o->word_regex)
2170                 o->word_regex = userdiff_word_regex(two, o->repo->index);
2171         if (!o->word_regex)
2172                 o->word_regex = diff_word_regex_cfg;
2173         if (o->word_regex) {
2174                 ecbdata->diff_words->word_regex = (regex_t *)
2175                         xmalloc(sizeof(regex_t));
2176                 if (regcomp(ecbdata->diff_words->word_regex,
2177                             o->word_regex,
2178                             REG_EXTENDED | REG_NEWLINE))
2179                         die("invalid regular expression: %s",
2180                             o->word_regex);
2181         }
2182         for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
2183                 if (o->word_diff == diff_words_styles[i].type) {
2184                         ecbdata->diff_words->style =
2185                                 &diff_words_styles[i];
2186                         break;
2187                 }
2188         }
2189         if (want_color(o->use_color)) {
2190                 struct diff_words_style *st = ecbdata->diff_words->style;
2191                 st->old_word.color = diff_get_color_opt(o, DIFF_FILE_OLD);
2192                 st->new_word.color = diff_get_color_opt(o, DIFF_FILE_NEW);
2193                 st->ctx.color = diff_get_color_opt(o, DIFF_CONTEXT);
2194         }
2195 }
2196
2197 static void free_diff_words_data(struct emit_callback *ecbdata)
2198 {
2199         if (ecbdata->diff_words) {
2200                 diff_words_flush(ecbdata);
2201                 free (ecbdata->diff_words->opt->emitted_symbols);
2202                 free (ecbdata->diff_words->opt);
2203                 free (ecbdata->diff_words->minus.text.ptr);
2204                 free (ecbdata->diff_words->minus.orig);
2205                 free (ecbdata->diff_words->plus.text.ptr);
2206                 free (ecbdata->diff_words->plus.orig);
2207                 if (ecbdata->diff_words->word_regex) {
2208                         regfree(ecbdata->diff_words->word_regex);
2209                         free(ecbdata->diff_words->word_regex);
2210                 }
2211                 FREE_AND_NULL(ecbdata->diff_words);
2212         }
2213 }
2214
2215 const char *diff_get_color(int diff_use_color, enum color_diff ix)
2216 {
2217         if (want_color(diff_use_color))
2218                 return diff_colors[ix];
2219         return "";
2220 }
2221
2222 const char *diff_line_prefix(struct diff_options *opt)
2223 {
2224         struct strbuf *msgbuf;
2225         if (!opt->output_prefix)
2226                 return "";
2227
2228         msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
2229         return msgbuf->buf;
2230 }
2231
2232 static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
2233 {
2234         const char *cp;
2235         unsigned long allot;
2236         size_t l = len;
2237
2238         cp = line;
2239         allot = l;
2240         while (0 < l) {
2241                 (void) utf8_width(&cp, &l);
2242                 if (!cp)
2243                         break; /* truncated in the middle? */
2244         }
2245         return allot - l;
2246 }
2247
2248 static void find_lno(const char *line, struct emit_callback *ecbdata)
2249 {
2250         const char *p;
2251         ecbdata->lno_in_preimage = 0;
2252         ecbdata->lno_in_postimage = 0;
2253         p = strchr(line, '-');
2254         if (!p)
2255                 return; /* cannot happen */
2256         ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
2257         p = strchr(p, '+');
2258         if (!p)
2259                 return; /* cannot happen */
2260         ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
2261 }
2262
2263 static void fn_out_consume(void *priv, char *line, unsigned long len)
2264 {
2265         struct emit_callback *ecbdata = priv;
2266         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
2267         struct diff_options *o = ecbdata->opt;
2268
2269         o->found_changes = 1;
2270
2271         if (ecbdata->header) {
2272                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
2273                                  ecbdata->header->buf, ecbdata->header->len, 0);
2274                 strbuf_reset(ecbdata->header);
2275                 ecbdata->header = NULL;
2276         }
2277
2278         if (ecbdata->label_path[0]) {
2279                 emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_MINUS,
2280                                  ecbdata->label_path[0],
2281                                  strlen(ecbdata->label_path[0]), 0);
2282                 emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_PLUS,
2283                                  ecbdata->label_path[1],
2284                                  strlen(ecbdata->label_path[1]), 0);
2285                 ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
2286         }
2287
2288         if (diff_suppress_blank_empty
2289             && len == 2 && line[0] == ' ' && line[1] == '\n') {
2290                 line[0] = '\n';
2291                 len = 1;
2292         }
2293
2294         if (line[0] == '@') {
2295                 if (ecbdata->diff_words)
2296                         diff_words_flush(ecbdata);
2297                 len = sane_truncate_line(ecbdata, line, len);
2298                 find_lno(line, ecbdata);
2299                 emit_hunk_header(ecbdata, line, len);
2300                 return;
2301         }
2302
2303         if (ecbdata->diff_words) {
2304                 enum diff_symbol s =
2305                         ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN ?
2306                         DIFF_SYMBOL_WORDS_PORCELAIN : DIFF_SYMBOL_WORDS;
2307                 if (line[0] == '-') {
2308                         diff_words_append(line, len,
2309                                           &ecbdata->diff_words->minus);
2310                         return;
2311                 } else if (line[0] == '+') {
2312                         diff_words_append(line, len,
2313                                           &ecbdata->diff_words->plus);
2314                         return;
2315                 } else if (starts_with(line, "\\ ")) {
2316                         /*
2317                          * Eat the "no newline at eof" marker as if we
2318                          * saw a "+" or "-" line with nothing on it,
2319                          * and return without diff_words_flush() to
2320                          * defer processing. If this is the end of
2321                          * preimage, more "+" lines may come after it.
2322                          */
2323                         return;
2324                 }
2325                 diff_words_flush(ecbdata);
2326                 emit_diff_symbol(o, s, line, len, 0);
2327                 return;
2328         }
2329
2330         switch (line[0]) {
2331         case '+':
2332                 ecbdata->lno_in_postimage++;
2333                 emit_add_line(reset, ecbdata, line + 1, len - 1);
2334                 break;
2335         case '-':
2336                 ecbdata->lno_in_preimage++;
2337                 emit_del_line(reset, ecbdata, line + 1, len - 1);
2338                 break;
2339         case ' ':
2340                 ecbdata->lno_in_postimage++;
2341                 ecbdata->lno_in_preimage++;
2342                 emit_context_line(reset, ecbdata, line + 1, len - 1);
2343                 break;
2344         default:
2345                 /* incomplete line at the end */
2346                 ecbdata->lno_in_preimage++;
2347                 emit_diff_symbol(o, DIFF_SYMBOL_CONTEXT_INCOMPLETE,
2348                                  line, len, 0);
2349                 break;
2350         }
2351 }
2352
2353 static void pprint_rename(struct strbuf *name, const char *a, const char *b)
2354 {
2355         const char *old_name = a;
2356         const char *new_name = b;
2357         int pfx_length, sfx_length;
2358         int pfx_adjust_for_slash;
2359         int len_a = strlen(a);
2360         int len_b = strlen(b);
2361         int a_midlen, b_midlen;
2362         int qlen_a = quote_c_style(a, NULL, NULL, 0);
2363         int qlen_b = quote_c_style(b, NULL, NULL, 0);
2364
2365         if (qlen_a || qlen_b) {
2366                 quote_c_style(a, name, NULL, 0);
2367                 strbuf_addstr(name, " => ");
2368                 quote_c_style(b, name, NULL, 0);
2369                 return;
2370         }
2371
2372         /* Find common prefix */
2373         pfx_length = 0;
2374         while (*old_name && *new_name && *old_name == *new_name) {
2375                 if (*old_name == '/')
2376                         pfx_length = old_name - a + 1;
2377                 old_name++;
2378                 new_name++;
2379         }
2380
2381         /* Find common suffix */
2382         old_name = a + len_a;
2383         new_name = b + len_b;
2384         sfx_length = 0;
2385         /*
2386          * If there is a common prefix, it must end in a slash.  In
2387          * that case we let this loop run 1 into the prefix to see the
2388          * same slash.
2389          *
2390          * If there is no common prefix, we cannot do this as it would
2391          * underrun the input strings.
2392          */
2393         pfx_adjust_for_slash = (pfx_length ? 1 : 0);
2394         while (a + pfx_length - pfx_adjust_for_slash <= old_name &&
2395                b + pfx_length - pfx_adjust_for_slash <= new_name &&
2396                *old_name == *new_name) {
2397                 if (*old_name == '/')
2398                         sfx_length = len_a - (old_name - a);
2399                 old_name--;
2400                 new_name--;
2401         }
2402
2403         /*
2404          * pfx{mid-a => mid-b}sfx
2405          * {pfx-a => pfx-b}sfx
2406          * pfx{sfx-a => sfx-b}
2407          * name-a => name-b
2408          */
2409         a_midlen = len_a - pfx_length - sfx_length;
2410         b_midlen = len_b - pfx_length - sfx_length;
2411         if (a_midlen < 0)
2412                 a_midlen = 0;
2413         if (b_midlen < 0)
2414                 b_midlen = 0;
2415
2416         strbuf_grow(name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
2417         if (pfx_length + sfx_length) {
2418                 strbuf_add(name, a, pfx_length);
2419                 strbuf_addch(name, '{');
2420         }
2421         strbuf_add(name, a + pfx_length, a_midlen);
2422         strbuf_addstr(name, " => ");
2423         strbuf_add(name, b + pfx_length, b_midlen);
2424         if (pfx_length + sfx_length) {
2425                 strbuf_addch(name, '}');
2426                 strbuf_add(name, a + len_a - sfx_length, sfx_length);
2427         }
2428 }
2429
2430 struct diffstat_t {
2431         int nr;
2432         int alloc;
2433         struct diffstat_file {
2434                 char *from_name;
2435                 char *name;
2436                 char *print_name;
2437                 const char *comments;
2438                 unsigned is_unmerged:1;
2439                 unsigned is_binary:1;
2440                 unsigned is_renamed:1;
2441                 unsigned is_interesting:1;
2442                 uintmax_t added, deleted;
2443         } **files;
2444 };
2445
2446 static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
2447                                           const char *name_a,
2448                                           const char *name_b)
2449 {
2450         struct diffstat_file *x;
2451         x = xcalloc(1, sizeof(*x));
2452         ALLOC_GROW(diffstat->files, diffstat->nr + 1, diffstat->alloc);
2453         diffstat->files[diffstat->nr++] = x;
2454         if (name_b) {
2455                 x->from_name = xstrdup(name_a);
2456                 x->name = xstrdup(name_b);
2457                 x->is_renamed = 1;
2458         }
2459         else {
2460                 x->from_name = NULL;
2461                 x->name = xstrdup(name_a);
2462         }
2463         return x;
2464 }
2465
2466 static void diffstat_consume(void *priv, char *line, unsigned long len)
2467 {
2468         struct diffstat_t *diffstat = priv;
2469         struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
2470
2471         if (line[0] == '+')
2472                 x->added++;
2473         else if (line[0] == '-')
2474                 x->deleted++;
2475 }
2476
2477 const char mime_boundary_leader[] = "------------";
2478
2479 static int scale_linear(int it, int width, int max_change)
2480 {
2481         if (!it)
2482                 return 0;
2483         /*
2484          * make sure that at least one '-' or '+' is printed if
2485          * there is any change to this path. The easiest way is to
2486          * scale linearly as if the alloted width is one column shorter
2487          * than it is, and then add 1 to the result.
2488          */
2489         return 1 + (it * (width - 1) / max_change);
2490 }
2491
2492 static void show_graph(struct strbuf *out, char ch, int cnt,
2493                        const char *set, const char *reset)
2494 {
2495         if (cnt <= 0)
2496                 return;
2497         strbuf_addstr(out, set);
2498         strbuf_addchars(out, ch, cnt);
2499         strbuf_addstr(out, reset);
2500 }
2501
2502 static void fill_print_name(struct diffstat_file *file)
2503 {
2504         struct strbuf pname = STRBUF_INIT;
2505
2506         if (file->print_name)
2507                 return;
2508
2509         if (file->is_renamed)
2510                 pprint_rename(&pname, file->from_name, file->name);
2511         else
2512                 quote_c_style(file->name, &pname, NULL, 0);
2513
2514         if (file->comments)
2515                 strbuf_addf(&pname, " (%s)", file->comments);
2516
2517         file->print_name = strbuf_detach(&pname, NULL);
2518 }
2519
2520 static void print_stat_summary_inserts_deletes(struct diff_options *options,
2521                 int files, int insertions, int deletions)
2522 {
2523         struct strbuf sb = STRBUF_INIT;
2524
2525         if (!files) {
2526                 assert(insertions == 0 && deletions == 0);
2527                 emit_diff_symbol(options, DIFF_SYMBOL_STATS_SUMMARY_NO_FILES,
2528                                  NULL, 0, 0);
2529                 return;
2530         }
2531
2532         strbuf_addf(&sb,
2533                     (files == 1) ? " %d file changed" : " %d files changed",
2534                     files);
2535
2536         /*
2537          * For binary diff, the caller may want to print "x files
2538          * changed" with insertions == 0 && deletions == 0.
2539          *
2540          * Not omitting "0 insertions(+), 0 deletions(-)" in this case
2541          * is probably less confusing (i.e skip over "2 files changed
2542          * but nothing about added/removed lines? Is this a bug in Git?").
2543          */
2544         if (insertions || deletions == 0) {
2545                 strbuf_addf(&sb,
2546                             (insertions == 1) ? ", %d insertion(+)" : ", %d insertions(+)",
2547                             insertions);
2548         }
2549
2550         if (deletions || insertions == 0) {
2551                 strbuf_addf(&sb,
2552                             (deletions == 1) ? ", %d deletion(-)" : ", %d deletions(-)",
2553                             deletions);
2554         }
2555         strbuf_addch(&sb, '\n');
2556         emit_diff_symbol(options, DIFF_SYMBOL_STATS_SUMMARY_INSERTS_DELETES,
2557                          sb.buf, sb.len, 0);
2558         strbuf_release(&sb);
2559 }
2560
2561 void print_stat_summary(FILE *fp, int files,
2562                         int insertions, int deletions)
2563 {
2564         struct diff_options o;
2565         memset(&o, 0, sizeof(o));
2566         o.file = fp;
2567
2568         print_stat_summary_inserts_deletes(&o, files, insertions, deletions);
2569 }
2570
2571 static void show_stats(struct diffstat_t *data, struct diff_options *options)
2572 {
2573         int i, len, add, del, adds = 0, dels = 0;
2574         uintmax_t max_change = 0, max_len = 0;
2575         int total_files = data->nr, count;
2576         int width, name_width, graph_width, number_width = 0, bin_width = 0;
2577         const char *reset, *add_c, *del_c;
2578         int extra_shown = 0;
2579         const char *line_prefix = diff_line_prefix(options);
2580         struct strbuf out = STRBUF_INIT;
2581
2582         if (data->nr == 0)
2583                 return;
2584
2585         count = options->stat_count ? options->stat_count : data->nr;
2586
2587         reset = diff_get_color_opt(options, DIFF_RESET);
2588         add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
2589         del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
2590
2591         /*
2592          * Find the longest filename and max number of changes
2593          */
2594         for (i = 0; (i < count) && (i < data->nr); i++) {
2595                 struct diffstat_file *file = data->files[i];
2596                 uintmax_t change = file->added + file->deleted;
2597
2598                 if (!file->is_interesting && (change == 0)) {
2599                         count++; /* not shown == room for one more */
2600                         continue;
2601                 }
2602                 fill_print_name(file);
2603                 len = strlen(file->print_name);
2604                 if (max_len < len)
2605                         max_len = len;
2606
2607                 if (file->is_unmerged) {
2608                         /* "Unmerged" is 8 characters */
2609                         bin_width = bin_width < 8 ? 8 : bin_width;
2610                         continue;
2611                 }
2612                 if (file->is_binary) {
2613                         /* "Bin XXX -> YYY bytes" */
2614                         int w = 14 + decimal_width(file->added)
2615                                 + decimal_width(file->deleted);
2616                         bin_width = bin_width < w ? w : bin_width;
2617                         /* Display change counts aligned with "Bin" */
2618                         number_width = 3;
2619                         continue;
2620                 }
2621
2622                 if (max_change < change)
2623                         max_change = change;
2624         }
2625         count = i; /* where we can stop scanning in data->files[] */
2626
2627         /*
2628          * We have width = stat_width or term_columns() columns total.
2629          * We want a maximum of min(max_len, stat_name_width) for the name part.
2630          * We want a maximum of min(max_change, stat_graph_width) for the +- part.
2631          * We also need 1 for " " and 4 + decimal_width(max_change)
2632          * for " | NNNN " and one the empty column at the end, altogether
2633          * 6 + decimal_width(max_change).
2634          *
2635          * If there's not enough space, we will use the smaller of
2636          * stat_name_width (if set) and 5/8*width for the filename,
2637          * and the rest for constant elements + graph part, but no more
2638          * than stat_graph_width for the graph part.
2639          * (5/8 gives 50 for filename and 30 for the constant parts + graph
2640          * for the standard terminal size).
2641          *
2642          * In other words: stat_width limits the maximum width, and
2643          * stat_name_width fixes the maximum width of the filename,
2644          * and is also used to divide available columns if there
2645          * aren't enough.
2646          *
2647          * Binary files are displayed with "Bin XXX -> YYY bytes"
2648          * instead of the change count and graph. This part is treated
2649          * similarly to the graph part, except that it is not
2650          * "scaled". If total width is too small to accommodate the
2651          * guaranteed minimum width of the filename part and the
2652          * separators and this message, this message will "overflow"
2653          * making the line longer than the maximum width.
2654          */
2655
2656         if (options->stat_width == -1)
2657                 width = term_columns() - strlen(line_prefix);
2658         else
2659                 width = options->stat_width ? options->stat_width : 80;
2660         number_width = decimal_width(max_change) > number_width ?
2661                 decimal_width(max_change) : number_width;
2662
2663         if (options->stat_graph_width == -1)
2664                 options->stat_graph_width = diff_stat_graph_width;
2665
2666         /*
2667          * Guarantee 3/8*16==6 for the graph part
2668          * and 5/8*16==10 for the filename part
2669          */
2670         if (width < 16 + 6 + number_width)
2671                 width = 16 + 6 + number_width;
2672
2673         /*
2674          * First assign sizes that are wanted, ignoring available width.
2675          * strlen("Bin XXX -> YYY bytes") == bin_width, and the part
2676          * starting from "XXX" should fit in graph_width.
2677          */
2678         graph_width = max_change + 4 > bin_width ? max_change : bin_width - 4;
2679         if (options->stat_graph_width &&
2680             options->stat_graph_width < graph_width)
2681                 graph_width = options->stat_graph_width;
2682
2683         name_width = (options->stat_name_width > 0 &&
2684                       options->stat_name_width < max_len) ?
2685                 options->stat_name_width : max_len;
2686
2687         /*
2688          * Adjust adjustable widths not to exceed maximum width
2689          */
2690         if (name_width + number_width + 6 + graph_width > width) {
2691                 if (graph_width > width * 3/8 - number_width - 6) {
2692                         graph_width = width * 3/8 - number_width - 6;
2693                         if (graph_width < 6)
2694                                 graph_width = 6;
2695                 }
2696
2697                 if (options->stat_graph_width &&
2698                     graph_width > options->stat_graph_width)
2699                         graph_width = options->stat_graph_width;
2700                 if (name_width > width - number_width - 6 - graph_width)
2701                         name_width = width - number_width - 6 - graph_width;
2702                 else
2703                         graph_width = width - number_width - 6 - name_width;
2704         }
2705
2706         /*
2707          * From here name_width is the width of the name area,
2708          * and graph_width is the width of the graph area.
2709          * max_change is used to scale graph properly.
2710          */
2711         for (i = 0; i < count; i++) {
2712                 const char *prefix = "";
2713                 struct diffstat_file *file = data->files[i];
2714                 char *name = file->print_name;
2715                 uintmax_t added = file->added;
2716                 uintmax_t deleted = file->deleted;
2717                 int name_len;
2718
2719                 if (!file->is_interesting && (added + deleted == 0))
2720                         continue;
2721
2722                 /*
2723                  * "scale" the filename
2724                  */
2725                 len = name_width;
2726                 name_len = strlen(name);
2727                 if (name_width < name_len) {
2728                         char *slash;
2729                         prefix = "...";
2730                         len -= 3;
2731                         name += name_len - len;
2732                         slash = strchr(name, '/');
2733                         if (slash)
2734                                 name = slash;
2735                 }
2736
2737                 if (file->is_binary) {
2738                         strbuf_addf(&out, " %s%-*s |", prefix, len, name);
2739                         strbuf_addf(&out, " %*s", number_width, "Bin");
2740                         if (!added && !deleted) {
2741                                 strbuf_addch(&out, '\n');
2742                                 emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2743                                                  out.buf, out.len, 0);
2744                                 strbuf_reset(&out);
2745                                 continue;
2746                         }
2747                         strbuf_addf(&out, " %s%"PRIuMAX"%s",
2748                                 del_c, deleted, reset);
2749                         strbuf_addstr(&out, " -> ");
2750                         strbuf_addf(&out, "%s%"PRIuMAX"%s",
2751                                 add_c, added, reset);
2752                         strbuf_addstr(&out, " bytes\n");
2753                         emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2754                                          out.buf, out.len, 0);
2755                         strbuf_reset(&out);
2756                         continue;
2757                 }
2758                 else if (file->is_unmerged) {
2759                         strbuf_addf(&out, " %s%-*s |", prefix, len, name);
2760                         strbuf_addstr(&out, " Unmerged\n");
2761                         emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2762                                          out.buf, out.len, 0);
2763                         strbuf_reset(&out);
2764                         continue;
2765                 }
2766
2767                 /*
2768                  * scale the add/delete
2769                  */
2770                 add = added;
2771                 del = deleted;
2772
2773                 if (graph_width <= max_change) {
2774                         int total = scale_linear(add + del, graph_width, max_change);
2775                         if (total < 2 && add && del)
2776                                 /* width >= 2 due to the sanity check */
2777                                 total = 2;
2778                         if (add < del) {
2779                                 add = scale_linear(add, graph_width, max_change);
2780                                 del = total - add;
2781                         } else {
2782                                 del = scale_linear(del, graph_width, max_change);
2783                                 add = total - del;
2784                         }
2785                 }
2786                 strbuf_addf(&out, " %s%-*s |", prefix, len, name);
2787                 strbuf_addf(&out, " %*"PRIuMAX"%s",
2788                         number_width, added + deleted,
2789                         added + deleted ? " " : "");
2790                 show_graph(&out, '+', add, add_c, reset);
2791                 show_graph(&out, '-', del, del_c, reset);
2792                 strbuf_addch(&out, '\n');
2793                 emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2794                                  out.buf, out.len, 0);
2795                 strbuf_reset(&out);
2796         }
2797
2798         for (i = 0; i < data->nr; i++) {
2799                 struct diffstat_file *file = data->files[i];
2800                 uintmax_t added = file->added;
2801                 uintmax_t deleted = file->deleted;
2802
2803                 if (file->is_unmerged ||
2804                     (!file->is_interesting && (added + deleted == 0))) {
2805                         total_files--;
2806                         continue;
2807                 }
2808
2809                 if (!file->is_binary) {
2810                         adds += added;
2811                         dels += deleted;
2812                 }
2813                 if (i < count)
2814                         continue;
2815                 if (!extra_shown)
2816                         emit_diff_symbol(options,
2817                                          DIFF_SYMBOL_STATS_SUMMARY_ABBREV,
2818                                          NULL, 0, 0);
2819                 extra_shown = 1;
2820         }
2821
2822         print_stat_summary_inserts_deletes(options, total_files, adds, dels);
2823         strbuf_release(&out);
2824 }
2825
2826 static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
2827 {
2828         int i, adds = 0, dels = 0, total_files = data->nr;
2829
2830         if (data->nr == 0)
2831                 return;
2832
2833         for (i = 0; i < data->nr; i++) {
2834                 int added = data->files[i]->added;
2835                 int deleted = data->files[i]->deleted;
2836
2837                 if (data->files[i]->is_unmerged ||
2838                     (!data->files[i]->is_interesting && (added + deleted == 0))) {
2839                         total_files--;
2840                 } else if (!data->files[i]->is_binary) { /* don't count bytes */
2841                         adds += added;
2842                         dels += deleted;
2843                 }
2844         }
2845         print_stat_summary_inserts_deletes(options, total_files, adds, dels);
2846 }
2847
2848 static void show_numstat(struct diffstat_t *data, struct diff_options *options)
2849 {
2850         int i;
2851
2852         if (data->nr == 0)
2853                 return;
2854
2855         for (i = 0; i < data->nr; i++) {
2856                 struct diffstat_file *file = data->files[i];
2857
2858                 fprintf(options->file, "%s", diff_line_prefix(options));
2859
2860                 if (file->is_binary)
2861                         fprintf(options->file, "-\t-\t");
2862                 else
2863                         fprintf(options->file,
2864                                 "%"PRIuMAX"\t%"PRIuMAX"\t",
2865                                 file->added, file->deleted);
2866                 if (options->line_termination) {
2867                         fill_print_name(file);
2868                         if (!file->is_renamed)
2869                                 write_name_quoted(file->name, options->file,
2870                                                   options->line_termination);
2871                         else {
2872                                 fputs(file->print_name, options->file);
2873                                 putc(options->line_termination, options->file);
2874                         }
2875                 } else {
2876                         if (file->is_renamed) {
2877                                 putc('\0', options->file);
2878                                 write_name_quoted(file->from_name, options->file, '\0');
2879                         }
2880                         write_name_quoted(file->name, options->file, '\0');
2881                 }
2882         }
2883 }
2884
2885 struct dirstat_file {
2886         const char *name;
2887         unsigned long changed;
2888 };
2889
2890 struct dirstat_dir {
2891         struct dirstat_file *files;
2892         int alloc, nr, permille, cumulative;
2893 };
2894
2895 static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
2896                 unsigned long changed, const char *base, int baselen)
2897 {
2898         unsigned long sum_changes = 0;
2899         unsigned int sources = 0;
2900         const char *line_prefix = diff_line_prefix(opt);
2901
2902         while (dir->nr) {
2903                 struct dirstat_file *f = dir->files;
2904                 int namelen = strlen(f->name);
2905                 unsigned long changes;
2906                 char *slash;
2907
2908                 if (namelen < baselen)
2909                         break;
2910                 if (memcmp(f->name, base, baselen))
2911                         break;
2912                 slash = strchr(f->name + baselen, '/');
2913                 if (slash) {
2914                         int newbaselen = slash + 1 - f->name;
2915                         changes = gather_dirstat(opt, dir, changed, f->name, newbaselen);
2916                         sources++;
2917                 } else {
2918                         changes = f->changed;
2919                         dir->files++;
2920                         dir->nr--;
2921                         sources += 2;
2922                 }
2923                 sum_changes += changes;
2924         }
2925
2926         /*
2927          * We don't report dirstat's for
2928          *  - the top level
2929          *  - or cases where everything came from a single directory
2930          *    under this directory (sources == 1).
2931          */
2932         if (baselen && sources != 1) {
2933                 if (sum_changes) {
2934                         int permille = sum_changes * 1000 / changed;
2935                         if (permille >= dir->permille) {
2936                                 fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
2937                                         permille / 10, permille % 10, baselen, base);
2938                                 if (!dir->cumulative)
2939                                         return 0;
2940                         }
2941                 }
2942         }
2943         return sum_changes;
2944 }
2945
2946 static int dirstat_compare(const void *_a, const void *_b)
2947 {
2948         const struct dirstat_file *a = _a;
2949         const struct dirstat_file *b = _b;
2950         return strcmp(a->name, b->name);
2951 }
2952
2953 static void show_dirstat(struct diff_options *options)
2954 {
2955         int i;
2956         unsigned long changed;
2957         struct dirstat_dir dir;
2958         struct diff_queue_struct *q = &diff_queued_diff;
2959
2960         dir.files = NULL;
2961         dir.alloc = 0;
2962         dir.nr = 0;
2963         dir.permille = options->dirstat_permille;
2964         dir.cumulative = options->flags.dirstat_cumulative;
2965
2966         changed = 0;
2967         for (i = 0; i < q->nr; i++) {
2968                 struct diff_filepair *p = q->queue[i];
2969                 const char *name;
2970                 unsigned long copied, added, damage;
2971
2972                 name = p->two->path ? p->two->path : p->one->path;
2973
2974                 if (p->one->oid_valid && p->two->oid_valid &&
2975                     oideq(&p->one->oid, &p->two->oid)) {
2976                         /*
2977                          * The SHA1 has not changed, so pre-/post-content is
2978                          * identical. We can therefore skip looking at the
2979                          * file contents altogether.
2980                          */
2981                         damage = 0;
2982                         goto found_damage;
2983                 }
2984
2985                 if (options->flags.dirstat_by_file) {
2986                         /*
2987                          * In --dirstat-by-file mode, we don't really need to
2988                          * look at the actual file contents at all.
2989                          * The fact that the SHA1 changed is enough for us to
2990                          * add this file to the list of results
2991                          * (with each file contributing equal damage).
2992                          */
2993                         damage = 1;
2994                         goto found_damage;
2995                 }
2996
2997                 if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
2998                         diff_populate_filespec(options->repo, p->one, 0);
2999                         diff_populate_filespec(options->repo, p->two, 0);
3000                         diffcore_count_changes(options->repo,
3001                                                p->one, p->two, NULL, NULL,
3002                                                &copied, &added);
3003                         diff_free_filespec_data(p->one);
3004                         diff_free_filespec_data(p->two);
3005                 } else if (DIFF_FILE_VALID(p->one)) {
3006                         diff_populate_filespec(options->repo, p->one, CHECK_SIZE_ONLY);
3007                         copied = added = 0;
3008                         diff_free_filespec_data(p->one);
3009                 } else if (DIFF_FILE_VALID(p->two)) {
3010                         diff_populate_filespec(options->repo, p->two, CHECK_SIZE_ONLY);
3011                         copied = 0;
3012                         added = p->two->size;
3013                         diff_free_filespec_data(p->two);
3014                 } else
3015                         continue;
3016
3017                 /*
3018                  * Original minus copied is the removed material,
3019                  * added is the new material.  They are both damages
3020                  * made to the preimage.
3021                  * If the resulting damage is zero, we know that
3022                  * diffcore_count_changes() considers the two entries to
3023                  * be identical, but since the oid changed, we
3024                  * know that there must have been _some_ kind of change,
3025                  * so we force all entries to have damage > 0.
3026                  */
3027                 damage = (p->one->size - copied) + added;
3028                 if (!damage)
3029                         damage = 1;
3030
3031 found_damage:
3032                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
3033                 dir.files[dir.nr].name = name;
3034                 dir.files[dir.nr].changed = damage;
3035                 changed += damage;
3036                 dir.nr++;
3037         }
3038
3039         /* This can happen even with many files, if everything was renames */
3040         if (!changed)
3041                 return;
3042
3043         /* Show all directories with more than x% of the changes */
3044         QSORT(dir.files, dir.nr, dirstat_compare);
3045         gather_dirstat(options, &dir, changed, "", 0);
3046 }
3047
3048 static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
3049 {
3050         int i;
3051         unsigned long changed;
3052         struct dirstat_dir dir;
3053
3054         if (data->nr == 0)
3055                 return;
3056
3057         dir.files = NULL;
3058         dir.alloc = 0;
3059         dir.nr = 0;
3060         dir.permille = options->dirstat_permille;
3061         dir.cumulative = options->flags.dirstat_cumulative;
3062
3063         changed = 0;
3064         for (i = 0; i < data->nr; i++) {
3065                 struct diffstat_file *file = data->files[i];
3066                 unsigned long damage = file->added + file->deleted;
3067                 if (file->is_binary)
3068                         /*
3069                          * binary files counts bytes, not lines. Must find some
3070                          * way to normalize binary bytes vs. textual lines.
3071                          * The following heuristic assumes that there are 64
3072                          * bytes per "line".
3073                          * This is stupid and ugly, but very cheap...
3074                          */
3075                         damage = DIV_ROUND_UP(damage, 64);
3076                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
3077                 dir.files[dir.nr].name = file->name;
3078                 dir.files[dir.nr].changed = damage;
3079                 changed += damage;
3080                 dir.nr++;
3081         }
3082
3083         /* This can happen even with many files, if everything was renames */
3084         if (!changed)
3085                 return;
3086
3087         /* Show all directories with more than x% of the changes */
3088         QSORT(dir.files, dir.nr, dirstat_compare);
3089         gather_dirstat(options, &dir, changed, "", 0);
3090 }
3091
3092 static void free_diffstat_info(struct diffstat_t *diffstat)
3093 {
3094         int i;
3095         for (i = 0; i < diffstat->nr; i++) {
3096                 struct diffstat_file *f = diffstat->files[i];
3097                 free(f->print_name);
3098                 free(f->name);
3099                 free(f->from_name);
3100                 free(f);
3101         }
3102         free(diffstat->files);
3103 }
3104
3105 struct checkdiff_t {
3106         const char *filename;
3107         int lineno;
3108         int conflict_marker_size;
3109         struct diff_options *o;
3110         unsigned ws_rule;
3111         unsigned status;
3112 };
3113
3114 static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
3115 {
3116         char firstchar;
3117         int cnt;
3118
3119         if (len < marker_size + 1)
3120                 return 0;
3121         firstchar = line[0];
3122         switch (firstchar) {
3123         case '=': case '>': case '<': case '|':
3124                 break;
3125         default:
3126                 return 0;
3127         }
3128         for (cnt = 1; cnt < marker_size; cnt++)
3129                 if (line[cnt] != firstchar)
3130                         return 0;
3131         /* line[1] thru line[marker_size-1] are same as firstchar */
3132         if (len < marker_size + 1 || !isspace(line[marker_size]))
3133                 return 0;
3134         return 1;
3135 }
3136
3137 static void checkdiff_consume_hunk(void *priv,
3138                                    long ob, long on, long nb, long nn,
3139                                    const char *func, long funclen)
3140
3141 {
3142         struct checkdiff_t *data = priv;
3143         data->lineno = nb - 1;
3144 }
3145
3146 static void checkdiff_consume(void *priv, char *line, unsigned long len)
3147 {
3148         struct checkdiff_t *data = priv;
3149         int marker_size = data->conflict_marker_size;
3150         const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
3151         const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
3152         const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
3153         char *err;
3154         const char *line_prefix;
3155
3156         assert(data->o);
3157         line_prefix = diff_line_prefix(data->o);
3158
3159         if (line[0] == '+') {
3160                 unsigned bad;
3161                 data->lineno++;
3162                 if (is_conflict_marker(line + 1, marker_size, len - 1)) {
3163                         data->status |= 1;
3164                         fprintf(data->o->file,
3165                                 "%s%s:%d: leftover conflict marker\n",
3166                                 line_prefix, data->filename, data->lineno);
3167                 }
3168                 bad = ws_check(line + 1, len - 1, data->ws_rule);
3169                 if (!bad)
3170                         return;
3171                 data->status |= bad;
3172                 err = whitespace_error_string(bad);
3173                 fprintf(data->o->file, "%s%s:%d: %s.\n",
3174                         line_prefix, data->filename, data->lineno, err);
3175                 free(err);
3176                 emit_line(data->o, set, reset, line, 1);
3177                 ws_check_emit(line + 1, len - 1, data->ws_rule,
3178                               data->o->file, set, reset, ws);
3179         } else if (line[0] == ' ') {
3180                 data->lineno++;
3181         }
3182 }
3183
3184 static unsigned char *deflate_it(char *data,
3185                                  unsigned long size,
3186                                  unsigned long *result_size)
3187 {
3188         int bound;
3189         unsigned char *deflated;
3190         git_zstream stream;
3191
3192         git_deflate_init(&stream, zlib_compression_level);
3193         bound = git_deflate_bound(&stream, size);
3194         deflated = xmalloc(bound);
3195         stream.next_out = deflated;
3196         stream.avail_out = bound;
3197
3198         stream.next_in = (unsigned char *)data;
3199         stream.avail_in = size;
3200         while (git_deflate(&stream, Z_FINISH) == Z_OK)
3201                 ; /* nothing */
3202         git_deflate_end(&stream);
3203         *result_size = stream.total_out;
3204         return deflated;
3205 }
3206
3207 static void emit_binary_diff_body(struct diff_options *o,
3208                                   mmfile_t *one, mmfile_t *two)
3209 {
3210         void *cp;
3211         void *delta;
3212         void *deflated;
3213         void *data;
3214         unsigned long orig_size;
3215         unsigned long delta_size;
3216         unsigned long deflate_size;
3217         unsigned long data_size;
3218
3219         /* We could do deflated delta, or we could do just deflated two,
3220          * whichever is smaller.
3221          */
3222         delta = NULL;
3223         deflated = deflate_it(two->ptr, two->size, &deflate_size);
3224         if (one->size && two->size) {
3225                 delta = diff_delta(one->ptr, one->size,
3226                                    two->ptr, two->size,
3227                                    &delta_size, deflate_size);
3228                 if (delta) {
3229                         void *to_free = delta;
3230                         orig_size = delta_size;
3231                         delta = deflate_it(delta, delta_size, &delta_size);
3232                         free(to_free);
3233                 }
3234         }
3235
3236         if (delta && delta_size < deflate_size) {
3237                 char *s = xstrfmt("%"PRIuMAX , (uintmax_t)orig_size);
3238                 emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_HEADER_DELTA,
3239                                  s, strlen(s), 0);
3240                 free(s);
3241                 free(deflated);
3242                 data = delta;
3243                 data_size = delta_size;
3244         } else {
3245                 char *s = xstrfmt("%lu", two->size);
3246                 emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_HEADER_LITERAL,
3247                                  s, strlen(s), 0);
3248                 free(s);
3249                 free(delta);
3250                 data = deflated;
3251                 data_size = deflate_size;
3252         }
3253
3254         /* emit data encoded in base85 */
3255         cp = data;
3256         while (data_size) {
3257                 int len;
3258                 int bytes = (52 < data_size) ? 52 : data_size;
3259                 char line[71];
3260                 data_size -= bytes;
3261                 if (bytes <= 26)
3262                         line[0] = bytes + 'A' - 1;
3263                 else
3264                         line[0] = bytes - 26 + 'a' - 1;
3265                 encode_85(line + 1, cp, bytes);
3266                 cp = (char *) cp + bytes;
3267
3268                 len = strlen(line);
3269                 line[len++] = '\n';
3270                 line[len] = '\0';
3271
3272                 emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_BODY,
3273                                  line, len, 0);
3274         }
3275         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_FOOTER, NULL, 0, 0);
3276         free(data);
3277 }
3278
3279 static void emit_binary_diff(struct diff_options *o,
3280                              mmfile_t *one, mmfile_t *two)
3281 {
3282         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_HEADER, NULL, 0, 0);
3283         emit_binary_diff_body(o, one, two);
3284         emit_binary_diff_body(o, two, one);
3285 }
3286
3287 int diff_filespec_is_binary(struct repository *r,
3288                             struct diff_filespec *one)
3289 {
3290         if (one->is_binary == -1) {
3291                 diff_filespec_load_driver(one, r->index);
3292                 if (one->driver->binary != -1)
3293                         one->is_binary = one->driver->binary;
3294                 else {
3295                         if (!one->data && DIFF_FILE_VALID(one))
3296                                 diff_populate_filespec(r, one, CHECK_BINARY);
3297                         if (one->is_binary == -1 && one->data)
3298                                 one->is_binary = buffer_is_binary(one->data,
3299                                                 one->size);
3300                         if (one->is_binary == -1)
3301                                 one->is_binary = 0;
3302                 }
3303         }
3304         return one->is_binary;
3305 }
3306
3307 static const struct userdiff_funcname *
3308 diff_funcname_pattern(struct diff_options *o, struct diff_filespec *one)
3309 {
3310         diff_filespec_load_driver(one, o->repo->index);
3311         return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
3312 }
3313
3314 void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
3315 {
3316         if (!options->a_prefix)
3317                 options->a_prefix = a;
3318         if (!options->b_prefix)
3319                 options->b_prefix = b;
3320 }
3321
3322 struct userdiff_driver *get_textconv(struct repository *r,
3323                                      struct diff_filespec *one)
3324 {
3325         if (!DIFF_FILE_VALID(one))
3326                 return NULL;
3327
3328         diff_filespec_load_driver(one, r->index);
3329         return userdiff_get_textconv(r, one->driver);
3330 }
3331
3332 static void builtin_diff(const char *name_a,
3333                          const char *name_b,
3334                          struct diff_filespec *one,
3335                          struct diff_filespec *two,
3336                          const char *xfrm_msg,
3337                          int must_show_header,
3338                          struct diff_options *o,
3339                          int complete_rewrite)
3340 {
3341         mmfile_t mf1, mf2;
3342         const char *lbl[2];
3343         char *a_one, *b_two;
3344         const char *meta = diff_get_color_opt(o, DIFF_METAINFO);
3345         const char *reset = diff_get_color_opt(o, DIFF_RESET);
3346         const char *a_prefix, *b_prefix;
3347         struct userdiff_driver *textconv_one = NULL;
3348         struct userdiff_driver *textconv_two = NULL;
3349         struct strbuf header = STRBUF_INIT;
3350         const char *line_prefix = diff_line_prefix(o);
3351
3352         diff_set_mnemonic_prefix(o, "a/", "b/");
3353         if (o->flags.reverse_diff) {
3354                 a_prefix = o->b_prefix;
3355                 b_prefix = o->a_prefix;
3356         } else {
3357                 a_prefix = o->a_prefix;
3358                 b_prefix = o->b_prefix;
3359         }
3360
3361         if (o->submodule_format == DIFF_SUBMODULE_LOG &&
3362             (!one->mode || S_ISGITLINK(one->mode)) &&
3363             (!two->mode || S_ISGITLINK(two->mode))) {
3364                 show_submodule_summary(o, one->path ? one->path : two->path,
3365                                 &one->oid, &two->oid,
3366                                 two->dirty_submodule);
3367                 return;
3368         } else if (o->submodule_format == DIFF_SUBMODULE_INLINE_DIFF &&
3369                    (!one->mode || S_ISGITLINK(one->mode)) &&
3370                    (!two->mode || S_ISGITLINK(two->mode))) {
3371                 show_submodule_inline_diff(o, one->path ? one->path : two->path,
3372                                 &one->oid, &two->oid,
3373                                 two->dirty_submodule);
3374                 return;
3375         }
3376
3377         if (o->flags.allow_textconv) {
3378                 textconv_one = get_textconv(o->repo, one);
3379                 textconv_two = get_textconv(o->repo, two);
3380         }
3381
3382         /* Never use a non-valid filename anywhere if at all possible */
3383         name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
3384         name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
3385
3386         a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
3387         b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
3388         lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
3389         lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
3390         strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, meta, a_one, b_two, reset);
3391         if (lbl[0][0] == '/') {
3392                 /* /dev/null */
3393                 strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, meta, two->mode, reset);
3394                 if (xfrm_msg)
3395                         strbuf_addstr(&header, xfrm_msg);
3396                 must_show_header = 1;
3397         }
3398         else if (lbl[1][0] == '/') {
3399                 strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, meta, one->mode, reset);
3400                 if (xfrm_msg)
3401                         strbuf_addstr(&header, xfrm_msg);
3402                 must_show_header = 1;
3403         }
3404         else {
3405                 if (one->mode != two->mode) {
3406                         strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, meta, one->mode, reset);
3407                         strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, meta, two->mode, reset);
3408                         must_show_header = 1;
3409                 }
3410                 if (xfrm_msg)
3411                         strbuf_addstr(&header, xfrm_msg);
3412
3413                 /*
3414                  * we do not run diff between different kind
3415                  * of objects.
3416                  */
3417                 if ((one->mode ^ two->mode) & S_IFMT)
3418                         goto free_ab_and_return;
3419                 if (complete_rewrite &&
3420                     (textconv_one || !diff_filespec_is_binary(o->repo, one)) &&
3421                     (textconv_two || !diff_filespec_is_binary(o->repo, two))) {
3422                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3423                                          header.buf, header.len, 0);
3424                         strbuf_reset(&header);
3425                         emit_rewrite_diff(name_a, name_b, one, two,
3426                                           textconv_one, textconv_two, o);
3427                         o->found_changes = 1;
3428                         goto free_ab_and_return;
3429                 }
3430         }
3431
3432         if (o->irreversible_delete && lbl[1][0] == '/') {
3433                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER, header.buf,
3434                                  header.len, 0);
3435                 strbuf_reset(&header);
3436                 goto free_ab_and_return;
3437         } else if (!o->flags.text &&
3438                    ( (!textconv_one && diff_filespec_is_binary(o->repo, one)) ||
3439                      (!textconv_two && diff_filespec_is_binary(o->repo, two)) )) {
3440                 struct strbuf sb = STRBUF_INIT;
3441                 if (!one->data && !two->data &&
3442                     S_ISREG(one->mode) && S_ISREG(two->mode) &&
3443                     !o->flags.binary) {
3444                         if (oideq(&one->oid, &two->oid)) {
3445                                 if (must_show_header)
3446                                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3447                                                          header.buf, header.len,
3448                                                          0);
3449                                 goto free_ab_and_return;
3450                         }
3451                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3452                                          header.buf, header.len, 0);
3453                         strbuf_addf(&sb, "%sBinary files %s and %s differ\n",
3454                                     diff_line_prefix(o), lbl[0], lbl[1]);
3455                         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_FILES,
3456                                          sb.buf, sb.len, 0);
3457                         strbuf_release(&sb);
3458                         goto free_ab_and_return;
3459                 }
3460                 if (fill_mmfile(o->repo, &mf1, one) < 0 ||
3461                     fill_mmfile(o->repo, &mf2, two) < 0)
3462                         die("unable to read files to diff");
3463                 /* Quite common confusing case */
3464                 if (mf1.size == mf2.size &&
3465                     !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
3466                         if (must_show_header)
3467                                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3468                                                  header.buf, header.len, 0);
3469                         goto free_ab_and_return;
3470                 }
3471                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER, header.buf, header.len, 0);
3472                 strbuf_reset(&header);
3473                 if (o->flags.binary)
3474                         emit_binary_diff(o, &mf1, &mf2);
3475                 else {
3476                         strbuf_addf(&sb, "%sBinary files %s and %s differ\n",
3477                                     diff_line_prefix(o), lbl[0], lbl[1]);
3478                         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_FILES,
3479                                          sb.buf, sb.len, 0);
3480                         strbuf_release(&sb);
3481                 }
3482                 o->found_changes = 1;
3483         } else {
3484                 /* Crazy xdl interfaces.. */
3485                 const char *diffopts = getenv("GIT_DIFF_OPTS");
3486                 const char *v;
3487                 xpparam_t xpp;
3488                 xdemitconf_t xecfg;
3489                 struct emit_callback ecbdata;
3490                 const struct userdiff_funcname *pe;
3491
3492                 if (must_show_header) {
3493                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3494                                          header.buf, header.len, 0);
3495                         strbuf_reset(&header);
3496                 }
3497
3498                 mf1.size = fill_textconv(o->repo, textconv_one, one, &mf1.ptr);
3499                 mf2.size = fill_textconv(o->repo, textconv_two, two, &mf2.ptr);
3500
3501                 pe = diff_funcname_pattern(o, one);
3502                 if (!pe)
3503                         pe = diff_funcname_pattern(o, two);
3504
3505                 memset(&xpp, 0, sizeof(xpp));
3506                 memset(&xecfg, 0, sizeof(xecfg));
3507                 memset(&ecbdata, 0, sizeof(ecbdata));
3508                 if (o->flags.suppress_diff_headers)
3509                         lbl[0] = NULL;
3510                 ecbdata.label_path = lbl;
3511                 ecbdata.color_diff = want_color(o->use_color);
3512                 ecbdata.ws_rule = whitespace_rule(o->repo->index, name_b);
3513                 if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
3514                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
3515                 ecbdata.opt = o;
3516                 if (header.len && !o->flags.suppress_diff_headers)
3517                         ecbdata.header = &header;
3518                 xpp.flags = o->xdl_opts;
3519                 xpp.anchors = o->anchors;
3520                 xpp.anchors_nr = o->anchors_nr;
3521                 xecfg.ctxlen = o->context;
3522                 xecfg.interhunkctxlen = o->interhunkcontext;
3523                 xecfg.flags = XDL_EMIT_FUNCNAMES;
3524                 if (o->flags.funccontext)
3525                         xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
3526                 if (pe)
3527                         xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
3528                 if (!diffopts)
3529                         ;
3530                 else if (skip_prefix(diffopts, "--unified=", &v))
3531                         xecfg.ctxlen = strtoul(v, NULL, 10);
3532                 else if (skip_prefix(diffopts, "-u", &v))
3533                         xecfg.ctxlen = strtoul(v, NULL, 10);
3534                 if (o->word_diff)
3535                         init_diff_words_data(&ecbdata, o, one, two);
3536                 if (xdi_diff_outf(&mf1, &mf2, NULL, fn_out_consume,
3537                                   &ecbdata, &xpp, &xecfg))
3538                         die("unable to generate diff for %s", one->path);
3539                 if (o->word_diff)
3540                         free_diff_words_data(&ecbdata);
3541                 if (textconv_one)
3542                         free(mf1.ptr);
3543                 if (textconv_two)
3544                         free(mf2.ptr);
3545                 xdiff_clear_find_func(&xecfg);
3546         }
3547
3548  free_ab_and_return:
3549         strbuf_release(&header);
3550         diff_free_filespec_data(one);
3551         diff_free_filespec_data(two);
3552         free(a_one);
3553         free(b_two);
3554         return;
3555 }
3556
3557 static char *get_compact_summary(const struct diff_filepair *p, int is_renamed)
3558 {
3559         if (!is_renamed) {
3560                 if (p->status == DIFF_STATUS_ADDED) {
3561                         if (S_ISLNK(p->two->mode))
3562                                 return "new +l";
3563                         else if ((p->two->mode & 0777) == 0755)
3564                                 return "new +x";
3565                         else
3566                                 return "new";
3567                 } else if (p->status == DIFF_STATUS_DELETED)
3568                         return "gone";
3569         }
3570         if (S_ISLNK(p->one->mode) && !S_ISLNK(p->two->mode))
3571                 return "mode -l";
3572         else if (!S_ISLNK(p->one->mode) && S_ISLNK(p->two->mode))
3573                 return "mode +l";
3574         else if ((p->one->mode & 0777) == 0644 &&
3575                  (p->two->mode & 0777) == 0755)
3576                 return "mode +x";
3577         else if ((p->one->mode & 0777) == 0755 &&
3578                  (p->two->mode & 0777) == 0644)
3579                 return "mode -x";
3580         return NULL;
3581 }
3582
3583 static void builtin_diffstat(const char *name_a, const char *name_b,
3584                              struct diff_filespec *one,
3585                              struct diff_filespec *two,
3586                              struct diffstat_t *diffstat,
3587                              struct diff_options *o,
3588                              struct diff_filepair *p)
3589 {
3590         mmfile_t mf1, mf2;
3591         struct diffstat_file *data;
3592         int same_contents;
3593         int complete_rewrite = 0;
3594
3595         if (!DIFF_PAIR_UNMERGED(p)) {
3596                 if (p->status == DIFF_STATUS_MODIFIED && p->score)
3597                         complete_rewrite = 1;
3598         }
3599
3600         data = diffstat_add(diffstat, name_a, name_b);
3601         data->is_interesting = p->status != DIFF_STATUS_UNKNOWN;
3602         if (o->flags.stat_with_summary)
3603                 data->comments = get_compact_summary(p, data->is_renamed);
3604
3605         if (!one || !two) {
3606                 data->is_unmerged = 1;
3607                 return;
3608         }
3609
3610         same_contents = oideq(&one->oid, &two->oid);
3611
3612         if (diff_filespec_is_binary(o->repo, one) ||
3613             diff_filespec_is_binary(o->repo, two)) {
3614                 data->is_binary = 1;
3615                 if (same_contents) {
3616                         data->added = 0;
3617                         data->deleted = 0;
3618                 } else {
3619                         data->added = diff_filespec_size(o->repo, two);
3620                         data->deleted = diff_filespec_size(o->repo, one);
3621                 }
3622         }
3623
3624         else if (complete_rewrite) {
3625                 diff_populate_filespec(o->repo, one, 0);
3626                 diff_populate_filespec(o->repo, two, 0);
3627                 data->deleted = count_lines(one->data, one->size);
3628                 data->added = count_lines(two->data, two->size);
3629         }
3630
3631         else if (!same_contents) {
3632                 /* Crazy xdl interfaces.. */
3633                 xpparam_t xpp;
3634                 xdemitconf_t xecfg;
3635
3636                 if (fill_mmfile(o->repo, &mf1, one) < 0 ||
3637                     fill_mmfile(o->repo, &mf2, two) < 0)
3638                         die("unable to read files to diff");
3639
3640                 memset(&xpp, 0, sizeof(xpp));
3641                 memset(&xecfg, 0, sizeof(xecfg));
3642                 xpp.flags = o->xdl_opts;
3643                 xpp.anchors = o->anchors;
3644                 xpp.anchors_nr = o->anchors_nr;
3645                 xecfg.ctxlen = o->context;
3646                 xecfg.interhunkctxlen = o->interhunkcontext;
3647                 if (xdi_diff_outf(&mf1, &mf2, discard_hunk_line,
3648                                   diffstat_consume, diffstat, &xpp, &xecfg))
3649                         die("unable to generate diffstat for %s", one->path);
3650         }
3651
3652         diff_free_filespec_data(one);
3653         diff_free_filespec_data(two);
3654 }
3655
3656 static void builtin_checkdiff(const char *name_a, const char *name_b,
3657                               const char *attr_path,
3658                               struct diff_filespec *one,
3659                               struct diff_filespec *two,
3660                               struct diff_options *o)
3661 {
3662         mmfile_t mf1, mf2;
3663         struct checkdiff_t data;
3664
3665         if (!two)
3666                 return;
3667
3668         memset(&data, 0, sizeof(data));
3669         data.filename = name_b ? name_b : name_a;
3670         data.lineno = 0;
3671         data.o = o;
3672         data.ws_rule = whitespace_rule(o->repo->index, attr_path);
3673         data.conflict_marker_size = ll_merge_marker_size(o->repo->index, attr_path);
3674
3675         if (fill_mmfile(o->repo, &mf1, one) < 0 ||
3676             fill_mmfile(o->repo, &mf2, two) < 0)
3677                 die("unable to read files to diff");
3678
3679         /*
3680          * All the other codepaths check both sides, but not checking
3681          * the "old" side here is deliberate.  We are checking the newly
3682          * introduced changes, and as long as the "new" side is text, we
3683          * can and should check what it introduces.
3684          */
3685         if (diff_filespec_is_binary(o->repo, two))
3686                 goto free_and_return;
3687         else {
3688                 /* Crazy xdl interfaces.. */
3689                 xpparam_t xpp;
3690                 xdemitconf_t xecfg;
3691
3692                 memset(&xpp, 0, sizeof(xpp));
3693                 memset(&xecfg, 0, sizeof(xecfg));
3694                 xecfg.ctxlen = 1; /* at least one context line */
3695                 xpp.flags = 0;
3696                 if (xdi_diff_outf(&mf1, &mf2, checkdiff_consume_hunk,
3697                                   checkdiff_consume, &data,
3698                                   &xpp, &xecfg))
3699                         die("unable to generate checkdiff for %s", one->path);
3700
3701                 if (data.ws_rule & WS_BLANK_AT_EOF) {
3702                         struct emit_callback ecbdata;
3703                         int blank_at_eof;
3704
3705                         ecbdata.ws_rule = data.ws_rule;
3706                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
3707                         blank_at_eof = ecbdata.blank_at_eof_in_postimage;
3708
3709                         if (blank_at_eof) {
3710                                 static char *err;
3711                                 if (!err)
3712                                         err = whitespace_error_string(WS_BLANK_AT_EOF);
3713                                 fprintf(o->file, "%s:%d: %s.\n",
3714                                         data.filename, blank_at_eof, err);
3715                                 data.status = 1; /* report errors */
3716                         }
3717                 }
3718         }
3719  free_and_return:
3720         diff_free_filespec_data(one);
3721         diff_free_filespec_data(two);
3722         if (data.status)
3723                 o->flags.check_failed = 1;
3724 }
3725
3726 struct diff_filespec *alloc_filespec(const char *path)
3727 {
3728         struct diff_filespec *spec;
3729
3730         FLEXPTR_ALLOC_STR(spec, path, path);
3731         spec->count = 1;
3732         spec->is_binary = -1;
3733         return spec;
3734 }
3735
3736 void free_filespec(struct diff_filespec *spec)
3737 {
3738         if (!--spec->count) {
3739                 diff_free_filespec_data(spec);
3740                 free(spec);
3741         }
3742 }
3743
3744 void fill_filespec(struct diff_filespec *spec, const struct object_id *oid,
3745                    int oid_valid, unsigned short mode)
3746 {
3747         if (mode) {
3748                 spec->mode = canon_mode(mode);
3749                 oidcpy(&spec->oid, oid);
3750                 spec->oid_valid = oid_valid;
3751         }
3752 }
3753
3754 /*
3755  * Given a name and sha1 pair, if the index tells us the file in
3756  * the work tree has that object contents, return true, so that
3757  * prepare_temp_file() does not have to inflate and extract.
3758  */
3759 static int reuse_worktree_file(struct index_state *istate,
3760                                const char *name,
3761                                const struct object_id *oid,
3762                                int want_file)
3763 {
3764         const struct cache_entry *ce;
3765         struct stat st;
3766         int pos, len;
3767
3768         /*
3769          * We do not read the cache ourselves here, because the
3770          * benchmark with my previous version that always reads cache
3771          * shows that it makes things worse for diff-tree comparing
3772          * two linux-2.6 kernel trees in an already checked out work
3773          * tree.  This is because most diff-tree comparisons deal with
3774          * only a small number of files, while reading the cache is
3775          * expensive for a large project, and its cost outweighs the
3776          * savings we get by not inflating the object to a temporary
3777          * file.  Practically, this code only helps when we are used
3778          * by diff-cache --cached, which does read the cache before
3779          * calling us.
3780          */
3781         if (!istate->cache)
3782                 return 0;
3783
3784         /* We want to avoid the working directory if our caller
3785          * doesn't need the data in a normal file, this system
3786          * is rather slow with its stat/open/mmap/close syscalls,
3787          * and the object is contained in a pack file.  The pack
3788          * is probably already open and will be faster to obtain
3789          * the data through than the working directory.  Loose
3790          * objects however would tend to be slower as they need
3791          * to be individually opened and inflated.
3792          */
3793         if (!FAST_WORKING_DIRECTORY && !want_file && has_object_pack(oid))
3794                 return 0;
3795
3796         /*
3797          * Similarly, if we'd have to convert the file contents anyway, that
3798          * makes the optimization not worthwhile.
3799          */
3800         if (!want_file && would_convert_to_git(istate, name))
3801                 return 0;
3802
3803         len = strlen(name);
3804         pos = index_name_pos(istate, name, len);
3805         if (pos < 0)
3806                 return 0;
3807         ce = istate->cache[pos];
3808
3809         /*
3810          * This is not the sha1 we are looking for, or
3811          * unreusable because it is not a regular file.
3812          */
3813         if (!oideq(oid, &ce->oid) || !S_ISREG(ce->ce_mode))
3814                 return 0;
3815
3816         /*
3817          * If ce is marked as "assume unchanged", there is no
3818          * guarantee that work tree matches what we are looking for.
3819          */
3820         if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
3821                 return 0;
3822
3823         /*
3824          * If ce matches the file in the work tree, we can reuse it.
3825          */
3826         if (ce_uptodate(ce) ||
3827             (!lstat(name, &st) && !ie_match_stat(istate, ce, &st, 0)))
3828                 return 1;
3829
3830         return 0;
3831 }
3832
3833 static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
3834 {
3835         struct strbuf buf = STRBUF_INIT;
3836         char *dirty = "";
3837
3838         /* Are we looking at the work tree? */
3839         if (s->dirty_submodule)
3840                 dirty = "-dirty";
3841
3842         strbuf_addf(&buf, "Subproject commit %s%s\n",
3843                     oid_to_hex(&s->oid), dirty);
3844         s->size = buf.len;
3845         if (size_only) {
3846                 s->data = NULL;
3847                 strbuf_release(&buf);
3848         } else {
3849                 s->data = strbuf_detach(&buf, NULL);
3850                 s->should_free = 1;
3851         }
3852         return 0;
3853 }
3854
3855 /*
3856  * While doing rename detection and pickaxe operation, we may need to
3857  * grab the data for the blob (or file) for our own in-core comparison.
3858  * diff_filespec has data and size fields for this purpose.
3859  */
3860 int diff_populate_filespec(struct repository *r,
3861                            struct diff_filespec *s,
3862                            unsigned int flags)
3863 {
3864         int size_only = flags & CHECK_SIZE_ONLY;
3865         int err = 0;
3866         int conv_flags = global_conv_flags_eol;
3867         /*
3868          * demote FAIL to WARN to allow inspecting the situation
3869          * instead of refusing.
3870          */
3871         if (conv_flags & CONV_EOL_RNDTRP_DIE)
3872                 conv_flags = CONV_EOL_RNDTRP_WARN;
3873
3874         if (!DIFF_FILE_VALID(s))
3875                 die("internal error: asking to populate invalid file.");
3876         if (S_ISDIR(s->mode))
3877                 return -1;
3878
3879         if (s->data)
3880                 return 0;
3881
3882         if (size_only && 0 < s->size)
3883                 return 0;
3884
3885         if (S_ISGITLINK(s->mode))
3886                 return diff_populate_gitlink(s, size_only);
3887
3888         if (!s->oid_valid ||
3889             reuse_worktree_file(r->index, s->path, &s->oid, 0)) {
3890                 struct strbuf buf = STRBUF_INIT;
3891                 struct stat st;
3892                 int fd;
3893
3894                 if (lstat(s->path, &st) < 0) {
3895                 err_empty:
3896                         err = -1;
3897                 empty:
3898                         s->data = (char *)"";
3899                         s->size = 0;
3900                         return err;
3901                 }
3902                 s->size = xsize_t(st.st_size);
3903                 if (!s->size)
3904                         goto empty;
3905                 if (S_ISLNK(st.st_mode)) {
3906                         struct strbuf sb = STRBUF_INIT;
3907
3908                         if (strbuf_readlink(&sb, s->path, s->size))
3909                                 goto err_empty;
3910                         s->size = sb.len;
3911                         s->data = strbuf_detach(&sb, NULL);
3912                         s->should_free = 1;
3913                         return 0;
3914                 }
3915
3916                 /*
3917                  * Even if the caller would be happy with getting
3918                  * only the size, we cannot return early at this
3919                  * point if the path requires us to run the content
3920                  * conversion.
3921                  */
3922                 if (size_only && !would_convert_to_git(r->index, s->path))
3923                         return 0;
3924
3925                 /*
3926                  * Note: this check uses xsize_t(st.st_size) that may
3927                  * not be the true size of the blob after it goes
3928                  * through convert_to_git().  This may not strictly be
3929                  * correct, but the whole point of big_file_threshold
3930                  * and is_binary check being that we want to avoid
3931                  * opening the file and inspecting the contents, this
3932                  * is probably fine.
3933                  */
3934                 if ((flags & CHECK_BINARY) &&
3935                     s->size > big_file_threshold && s->is_binary == -1) {
3936                         s->is_binary = 1;
3937                         return 0;
3938                 }
3939                 fd = open(s->path, O_RDONLY);
3940                 if (fd < 0)
3941                         goto err_empty;
3942                 s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
3943                 close(fd);
3944                 s->should_munmap = 1;
3945
3946                 /*
3947                  * Convert from working tree format to canonical git format
3948                  */
3949                 if (convert_to_git(r->index, s->path, s->data, s->size, &buf, conv_flags)) {
3950                         size_t size = 0;
3951                         munmap(s->data, s->size);
3952                         s->should_munmap = 0;
3953                         s->data = strbuf_detach(&buf, &size);
3954                         s->size = size;
3955                         s->should_free = 1;
3956                 }
3957         }
3958         else {
3959                 enum object_type type;
3960                 if (size_only || (flags & CHECK_BINARY)) {
3961                         type = oid_object_info(r, &s->oid, &s->size);
3962                         if (type < 0)
3963                                 die("unable to read %s",
3964                                     oid_to_hex(&s->oid));
3965                         if (size_only)
3966                                 return 0;
3967                         if (s->size > big_file_threshold && s->is_binary == -1) {
3968                                 s->is_binary = 1;
3969                                 return 0;
3970                         }
3971                 }
3972                 s->data = read_object_file(&s->oid, &type, &s->size);
3973                 if (!s->data)
3974                         die("unable to read %s", oid_to_hex(&s->oid));
3975                 s->should_free = 1;
3976         }
3977         return 0;
3978 }
3979
3980 void diff_free_filespec_blob(struct diff_filespec *s)
3981 {
3982         if (s->should_free)
3983                 free(s->data);
3984         else if (s->should_munmap)
3985                 munmap(s->data, s->size);
3986
3987         if (s->should_free || s->should_munmap) {
3988                 s->should_free = s->should_munmap = 0;
3989                 s->data = NULL;
3990         }
3991 }
3992
3993 void diff_free_filespec_data(struct diff_filespec *s)
3994 {
3995         diff_free_filespec_blob(s);
3996         FREE_AND_NULL(s->cnt_data);
3997 }
3998
3999 static void prep_temp_blob(struct index_state *istate,
4000                            const char *path, struct diff_tempfile *temp,
4001                            void *blob,
4002                            unsigned long size,
4003                            const struct object_id *oid,
4004                            int mode)
4005 {
4006         struct strbuf buf = STRBUF_INIT;
4007         struct strbuf tempfile = STRBUF_INIT;
4008         char *path_dup = xstrdup(path);
4009         const char *base = basename(path_dup);
4010
4011         /* Generate "XXXXXX_basename.ext" */
4012         strbuf_addstr(&tempfile, "XXXXXX_");
4013         strbuf_addstr(&tempfile, base);
4014
4015         temp->tempfile = mks_tempfile_ts(tempfile.buf, strlen(base) + 1);
4016         if (!temp->tempfile)
4017                 die_errno("unable to create temp-file");
4018         if (convert_to_working_tree(istate, path,
4019                         (const char *)blob, (size_t)size, &buf)) {
4020                 blob = buf.buf;
4021                 size = buf.len;
4022         }
4023         if (write_in_full(temp->tempfile->fd, blob, size) < 0 ||
4024             close_tempfile_gently(temp->tempfile))
4025                 die_errno("unable to write temp-file");
4026         temp->name = get_tempfile_path(temp->tempfile);
4027         oid_to_hex_r(temp->hex, oid);
4028         xsnprintf(temp->mode, sizeof(temp->mode), "%06o", mode);
4029         strbuf_release(&buf);
4030         strbuf_release(&tempfile);
4031         free(path_dup);
4032 }
4033
4034 static struct diff_tempfile *prepare_temp_file(struct repository *r,
4035                                                const char *name,
4036                                                struct diff_filespec *one)
4037 {
4038         struct diff_tempfile *temp = claim_diff_tempfile();
4039
4040         if (!DIFF_FILE_VALID(one)) {
4041         not_a_valid_file:
4042                 /* A '-' entry produces this for file-2, and
4043                  * a '+' entry produces this for file-1.
4044                  */
4045                 temp->name = "/dev/null";
4046                 xsnprintf(temp->hex, sizeof(temp->hex), ".");
4047                 xsnprintf(temp->mode, sizeof(temp->mode), ".");
4048                 return temp;
4049         }
4050
4051         if (!S_ISGITLINK(one->mode) &&
4052             (!one->oid_valid ||
4053              reuse_worktree_file(r->index, name, &one->oid, 1))) {
4054                 struct stat st;
4055                 if (lstat(name, &st) < 0) {
4056                         if (errno == ENOENT)
4057                                 goto not_a_valid_file;
4058                         die_errno("stat(%s)", name);
4059                 }
4060                 if (S_ISLNK(st.st_mode)) {
4061                         struct strbuf sb = STRBUF_INIT;
4062                         if (strbuf_readlink(&sb, name, st.st_size) < 0)
4063                                 die_errno("readlink(%s)", name);
4064                         prep_temp_blob(r->index, name, temp, sb.buf, sb.len,
4065                                        (one->oid_valid ?
4066                                         &one->oid : &null_oid),
4067                                        (one->oid_valid ?
4068                                         one->mode : S_IFLNK));
4069                         strbuf_release(&sb);
4070                 }
4071                 else {
4072                         /* we can borrow from the file in the work tree */
4073                         temp->name = name;
4074                         if (!one->oid_valid)
4075                                 oid_to_hex_r(temp->hex, &null_oid);
4076                         else
4077                                 oid_to_hex_r(temp->hex, &one->oid);
4078                         /* Even though we may sometimes borrow the
4079                          * contents from the work tree, we always want
4080                          * one->mode.  mode is trustworthy even when
4081                          * !(one->oid_valid), as long as
4082                          * DIFF_FILE_VALID(one).
4083                          */
4084                         xsnprintf(temp->mode, sizeof(temp->mode), "%06o", one->mode);
4085                 }
4086                 return temp;
4087         }
4088         else {
4089                 if (diff_populate_filespec(r, one, 0))
4090                         die("cannot read data blob for %s", one->path);
4091                 prep_temp_blob(r->index, name, temp,
4092                                one->data, one->size,
4093                                &one->oid, one->mode);
4094         }
4095         return temp;
4096 }
4097
4098 static void add_external_diff_name(struct repository *r,
4099                                    struct argv_array *argv,
4100                                    const char *name,
4101                                    struct diff_filespec *df)
4102 {
4103         struct diff_tempfile *temp = prepare_temp_file(r, name, df);
4104         argv_array_push(argv, temp->name);
4105         argv_array_push(argv, temp->hex);
4106         argv_array_push(argv, temp->mode);
4107 }
4108
4109 /* An external diff command takes:
4110  *
4111  * diff-cmd name infile1 infile1-sha1 infile1-mode \
4112  *               infile2 infile2-sha1 infile2-mode [ rename-to ]
4113  *
4114  */
4115 static void run_external_diff(const char *pgm,
4116                               const char *name,
4117                               const char *other,
4118                               struct diff_filespec *one,
4119                               struct diff_filespec *two,
4120                               const char *xfrm_msg,
4121                               int complete_rewrite,
4122                               struct diff_options *o)
4123 {
4124         struct argv_array argv = ARGV_ARRAY_INIT;
4125         struct argv_array env = ARGV_ARRAY_INIT;
4126         struct diff_queue_struct *q = &diff_queued_diff;
4127
4128         argv_array_push(&argv, pgm);
4129         argv_array_push(&argv, name);
4130
4131         if (one && two) {
4132                 add_external_diff_name(o->repo, &argv, name, one);
4133                 if (!other)
4134                         add_external_diff_name(o->repo, &argv, name, two);
4135                 else {
4136                         add_external_diff_name(o->repo, &argv, other, two);
4137                         argv_array_push(&argv, other);
4138                         argv_array_push(&argv, xfrm_msg);
4139                 }
4140         }
4141
4142         argv_array_pushf(&env, "GIT_DIFF_PATH_COUNTER=%d", ++o->diff_path_counter);
4143         argv_array_pushf(&env, "GIT_DIFF_PATH_TOTAL=%d", q->nr);
4144
4145         if (run_command_v_opt_cd_env(argv.argv, RUN_USING_SHELL, NULL, env.argv))
4146                 die(_("external diff died, stopping at %s"), name);
4147
4148         remove_tempfile();
4149         argv_array_clear(&argv);
4150         argv_array_clear(&env);
4151 }
4152
4153 static int similarity_index(struct diff_filepair *p)
4154 {
4155         return p->score * 100 / MAX_SCORE;
4156 }
4157
4158 static const char *diff_abbrev_oid(const struct object_id *oid, int abbrev)
4159 {
4160         if (startup_info->have_repository)
4161                 return find_unique_abbrev(oid, abbrev);
4162         else {
4163                 char *hex = oid_to_hex(oid);
4164                 if (abbrev < 0)
4165                         abbrev = FALLBACK_DEFAULT_ABBREV;
4166                 if (abbrev > the_hash_algo->hexsz)
4167                         BUG("oid abbreviation out of range: %d", abbrev);
4168                 if (abbrev)
4169                         hex[abbrev] = '\0';
4170                 return hex;
4171         }
4172 }
4173
4174 static void fill_metainfo(struct strbuf *msg,
4175                           const char *name,
4176                           const char *other,
4177                           struct diff_filespec *one,
4178                           struct diff_filespec *two,
4179                           struct diff_options *o,
4180                           struct diff_filepair *p,
4181                           int *must_show_header,
4182                           int use_color)
4183 {
4184         const char *set = diff_get_color(use_color, DIFF_METAINFO);
4185         const char *reset = diff_get_color(use_color, DIFF_RESET);
4186         const char *line_prefix = diff_line_prefix(o);
4187
4188         *must_show_header = 1;
4189         strbuf_init(msg, PATH_MAX * 2 + 300);
4190         switch (p->status) {
4191         case DIFF_STATUS_COPIED:
4192                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
4193                             line_prefix, set, similarity_index(p));
4194                 strbuf_addf(msg, "%s\n%s%scopy from ",
4195                             reset,  line_prefix, set);
4196                 quote_c_style(name, msg, NULL, 0);
4197                 strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
4198                 quote_c_style(other, msg, NULL, 0);
4199                 strbuf_addf(msg, "%s\n", reset);
4200                 break;
4201         case DIFF_STATUS_RENAMED:
4202                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
4203                             line_prefix, set, similarity_index(p));
4204                 strbuf_addf(msg, "%s\n%s%srename from ",
4205                             reset, line_prefix, set);
4206                 quote_c_style(name, msg, NULL, 0);
4207                 strbuf_addf(msg, "%s\n%s%srename to ",
4208                             reset, line_prefix, set);
4209                 quote_c_style(other, msg, NULL, 0);
4210                 strbuf_addf(msg, "%s\n", reset);
4211                 break;
4212         case DIFF_STATUS_MODIFIED:
4213                 if (p->score) {
4214                         strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
4215                                     line_prefix,
4216                                     set, similarity_index(p), reset);
4217                         break;
4218                 }
4219                 /* fallthru */
4220         default:
4221                 *must_show_header = 0;
4222         }
4223         if (one && two && !oideq(&one->oid, &two->oid)) {
4224                 const unsigned hexsz = the_hash_algo->hexsz;
4225                 int abbrev = o->flags.full_index ? hexsz : DEFAULT_ABBREV;
4226
4227                 if (o->flags.binary) {
4228                         mmfile_t mf;
4229                         if ((!fill_mmfile(o->repo, &mf, one) &&
4230                              diff_filespec_is_binary(o->repo, one)) ||
4231                             (!fill_mmfile(o->repo, &mf, two) &&
4232                              diff_filespec_is_binary(o->repo, two)))
4233                                 abbrev = hexsz;
4234                 }
4235                 strbuf_addf(msg, "%s%sindex %s..%s", line_prefix, set,
4236                             diff_abbrev_oid(&one->oid, abbrev),
4237                             diff_abbrev_oid(&two->oid, abbrev));
4238                 if (one->mode == two->mode)
4239                         strbuf_addf(msg, " %06o", one->mode);
4240                 strbuf_addf(msg, "%s\n", reset);
4241         }
4242 }
4243
4244 static void run_diff_cmd(const char *pgm,
4245                          const char *name,
4246                          const char *other,
4247                          const char *attr_path,
4248                          struct diff_filespec *one,
4249                          struct diff_filespec *two,
4250                          struct strbuf *msg,
4251                          struct diff_options *o,
4252                          struct diff_filepair *p)
4253 {
4254         const char *xfrm_msg = NULL;
4255         int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
4256         int must_show_header = 0;
4257
4258
4259         if (o->flags.allow_external) {
4260                 struct userdiff_driver *drv;
4261
4262                 drv = userdiff_find_by_path(o->repo->index, attr_path);
4263                 if (drv && drv->external)
4264                         pgm = drv->external;
4265         }
4266
4267         if (msg) {
4268                 /*
4269                  * don't use colors when the header is intended for an
4270                  * external diff driver
4271                  */
4272                 fill_metainfo(msg, name, other, one, two, o, p,
4273                               &must_show_header,
4274                               want_color(o->use_color) && !pgm);
4275                 xfrm_msg = msg->len ? msg->buf : NULL;
4276         }
4277
4278         if (pgm) {
4279                 run_external_diff(pgm, name, other, one, two, xfrm_msg,
4280                                   complete_rewrite, o);
4281                 return;
4282         }
4283         if (one && two)
4284                 builtin_diff(name, other ? other : name,
4285                              one, two, xfrm_msg, must_show_header,
4286                              o, complete_rewrite);
4287         else
4288                 fprintf(o->file, "* Unmerged path %s\n", name);
4289 }
4290
4291 static void diff_fill_oid_info(struct diff_filespec *one, struct index_state *istate)
4292 {
4293         if (DIFF_FILE_VALID(one)) {
4294                 if (!one->oid_valid) {
4295                         struct stat st;
4296                         if (one->is_stdin) {
4297                                 oidclr(&one->oid);
4298                                 return;
4299                         }
4300                         if (lstat(one->path, &st) < 0)
4301                                 die_errno("stat '%s'", one->path);
4302                         if (index_path(istate, &one->oid, one->path, &st, 0))
4303                                 die("cannot hash %s", one->path);
4304                 }
4305         }
4306         else
4307                 oidclr(&one->oid);
4308 }
4309
4310 static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
4311 {
4312         /* Strip the prefix but do not molest /dev/null and absolute paths */
4313         if (*namep && !is_absolute_path(*namep)) {
4314                 *namep += prefix_length;
4315                 if (**namep == '/')
4316                         ++*namep;
4317         }
4318         if (*otherp && !is_absolute_path(*otherp)) {
4319                 *otherp += prefix_length;
4320                 if (**otherp == '/')
4321                         ++*otherp;
4322         }
4323 }
4324
4325 static void run_diff(struct diff_filepair *p, struct diff_options *o)
4326 {
4327         const char *pgm = external_diff();
4328         struct strbuf msg;
4329         struct diff_filespec *one = p->one;
4330         struct diff_filespec *two = p->two;
4331         const char *name;
4332         const char *other;
4333         const char *attr_path;
4334
4335         name  = one->path;
4336         other = (strcmp(name, two->path) ? two->path : NULL);
4337         attr_path = name;
4338         if (o->prefix_length)
4339                 strip_prefix(o->prefix_length, &name, &other);
4340
4341         if (!o->flags.allow_external)
4342                 pgm = NULL;
4343
4344         if (DIFF_PAIR_UNMERGED(p)) {
4345                 run_diff_cmd(pgm, name, NULL, attr_path,
4346                              NULL, NULL, NULL, o, p);
4347                 return;
4348         }
4349
4350         diff_fill_oid_info(one, o->repo->index);
4351         diff_fill_oid_info(two, o->repo->index);
4352
4353         if (!pgm &&
4354             DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
4355             (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
4356                 /*
4357                  * a filepair that changes between file and symlink
4358                  * needs to be split into deletion and creation.
4359                  */
4360                 struct diff_filespec *null = alloc_filespec(two->path);
4361                 run_diff_cmd(NULL, name, other, attr_path,
4362                              one, null, &msg,
4363                              o, p);
4364                 free(null);
4365                 strbuf_release(&msg);
4366
4367                 null = alloc_filespec(one->path);
4368                 run_diff_cmd(NULL, name, other, attr_path,
4369                              null, two, &msg, o, p);
4370                 free(null);
4371         }
4372         else
4373                 run_diff_cmd(pgm, name, other, attr_path,
4374                              one, two, &msg, o, p);
4375
4376         strbuf_release(&msg);
4377 }
4378
4379 static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
4380                          struct diffstat_t *diffstat)
4381 {
4382         const char *name;
4383         const char *other;
4384
4385         if (DIFF_PAIR_UNMERGED(p)) {
4386                 /* unmerged */
4387                 builtin_diffstat(p->one->path, NULL, NULL, NULL,
4388                                  diffstat, o, p);
4389                 return;
4390         }
4391
4392         name = p->one->path;
4393         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
4394
4395         if (o->prefix_length)
4396                 strip_prefix(o->prefix_length, &name, &other);
4397
4398         diff_fill_oid_info(p->one, o->repo->index);
4399         diff_fill_oid_info(p->two, o->repo->index);
4400
4401         builtin_diffstat(name, other, p->one, p->two,
4402                          diffstat, o, p);
4403 }
4404
4405 static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
4406 {
4407         const char *name;
4408         const char *other;
4409         const char *attr_path;
4410
4411         if (DIFF_PAIR_UNMERGED(p)) {
4412                 /* unmerged */
4413                 return;
4414         }
4415
4416         name = p->one->path;
4417         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
4418         attr_path = other ? other : name;
4419
4420         if (o->prefix_length)
4421                 strip_prefix(o->prefix_length, &name, &other);
4422
4423         diff_fill_oid_info(p->one, o->repo->index);
4424         diff_fill_oid_info(p->two, o->repo->index);
4425
4426         builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
4427 }
4428
4429 static void prep_parse_options(struct diff_options *options);
4430
4431 void repo_diff_setup(struct repository *r, struct diff_options *options)
4432 {
4433         memcpy(options, &default_diff_options, sizeof(*options));
4434
4435         options->file = stdout;
4436         options->repo = r;
4437
4438         options->output_indicators[OUTPUT_INDICATOR_NEW] = '+';
4439         options->output_indicators[OUTPUT_INDICATOR_OLD] = '-';
4440         options->output_indicators[OUTPUT_INDICATOR_CONTEXT] = ' ';
4441         options->abbrev = DEFAULT_ABBREV;
4442         options->line_termination = '\n';
4443         options->break_opt = -1;
4444         options->rename_limit = -1;
4445         options->dirstat_permille = diff_dirstat_permille_default;
4446         options->context = diff_context_default;
4447         options->interhunkcontext = diff_interhunk_context_default;
4448         options->ws_error_highlight = ws_error_highlight_default;
4449         options->flags.rename_empty = 1;
4450         options->objfind = NULL;
4451
4452         /* pathchange left =NULL by default */
4453         options->change = diff_change;
4454         options->add_remove = diff_addremove;
4455         options->use_color = diff_use_color_default;
4456         options->detect_rename = diff_detect_rename_default;
4457         options->xdl_opts |= diff_algorithm;
4458         if (diff_indent_heuristic)
4459                 DIFF_XDL_SET(options, INDENT_HEURISTIC);
4460
4461         options->orderfile = diff_order_file_cfg;
4462
4463         if (diff_no_prefix) {
4464                 options->a_prefix = options->b_prefix = "";
4465         } else if (!diff_mnemonic_prefix) {
4466                 options->a_prefix = "a/";
4467                 options->b_prefix = "b/";
4468         }
4469
4470         options->color_moved = diff_color_moved_default;
4471         options->color_moved_ws_handling = diff_color_moved_ws_default;
4472
4473         prep_parse_options(options);
4474 }
4475
4476 void diff_setup_done(struct diff_options *options)
4477 {
4478         unsigned check_mask = DIFF_FORMAT_NAME |
4479                               DIFF_FORMAT_NAME_STATUS |
4480                               DIFF_FORMAT_CHECKDIFF |
4481                               DIFF_FORMAT_NO_OUTPUT;
4482         /*
4483          * This must be signed because we're comparing against a potentially
4484          * negative value.
4485          */
4486         const int hexsz = the_hash_algo->hexsz;
4487
4488         if (options->set_default)
4489                 options->set_default(options);
4490
4491         if (HAS_MULTI_BITS(options->output_format & check_mask))
4492                 die(_("--name-only, --name-status, --check and -s are mutually exclusive"));
4493
4494         if (HAS_MULTI_BITS(options->pickaxe_opts & DIFF_PICKAXE_KINDS_MASK))
4495                 die(_("-G, -S and --find-object are mutually exclusive"));
4496
4497         /*
4498          * Most of the time we can say "there are changes"
4499          * only by checking if there are changed paths, but
4500          * --ignore-whitespace* options force us to look
4501          * inside contents.
4502          */
4503
4504         if ((options->xdl_opts & XDF_WHITESPACE_FLAGS))
4505                 options->flags.diff_from_contents = 1;
4506         else
4507                 options->flags.diff_from_contents = 0;
4508
4509         if (options->flags.find_copies_harder)
4510                 options->detect_rename = DIFF_DETECT_COPY;
4511
4512         if (!options->flags.relative_name)
4513                 options->prefix = NULL;
4514         if (options->prefix)
4515                 options->prefix_length = strlen(options->prefix);
4516         else
4517                 options->prefix_length = 0;
4518
4519         if (options->output_format & (DIFF_FORMAT_NAME |
4520                                       DIFF_FORMAT_NAME_STATUS |
4521                                       DIFF_FORMAT_CHECKDIFF |
4522                                       DIFF_FORMAT_NO_OUTPUT))
4523                 options->output_format &= ~(DIFF_FORMAT_RAW |
4524                                             DIFF_FORMAT_NUMSTAT |
4525                                             DIFF_FORMAT_DIFFSTAT |
4526                                             DIFF_FORMAT_SHORTSTAT |
4527                                             DIFF_FORMAT_DIRSTAT |
4528                                             DIFF_FORMAT_SUMMARY |
4529                                             DIFF_FORMAT_PATCH);
4530
4531         /*
4532          * These cases always need recursive; we do not drop caller-supplied
4533          * recursive bits for other formats here.
4534          */
4535         if (options->output_format & (DIFF_FORMAT_PATCH |
4536                                       DIFF_FORMAT_NUMSTAT |
4537                                       DIFF_FORMAT_DIFFSTAT |
4538                                       DIFF_FORMAT_SHORTSTAT |
4539                                       DIFF_FORMAT_DIRSTAT |
4540                                       DIFF_FORMAT_SUMMARY |
4541                                       DIFF_FORMAT_CHECKDIFF))
4542                 options->flags.recursive = 1;
4543         /*
4544          * Also pickaxe would not work very well if you do not say recursive
4545          */
4546         if (options->pickaxe_opts & DIFF_PICKAXE_KINDS_MASK)
4547                 options->flags.recursive = 1;
4548         /*
4549          * When patches are generated, submodules diffed against the work tree
4550          * must be checked for dirtiness too so it can be shown in the output
4551          */
4552         if (options->output_format & DIFF_FORMAT_PATCH)
4553                 options->flags.dirty_submodules = 1;
4554
4555         if (options->detect_rename && options->rename_limit < 0)
4556                 options->rename_limit = diff_rename_limit_default;
4557         if (hexsz < options->abbrev)
4558                 options->abbrev = hexsz; /* full */
4559
4560         /*
4561          * It does not make sense to show the first hit we happened
4562          * to have found.  It does not make sense not to return with
4563          * exit code in such a case either.
4564          */
4565         if (options->flags.quick) {
4566                 options->output_format = DIFF_FORMAT_NO_OUTPUT;
4567                 options->flags.exit_with_status = 1;
4568         }
4569
4570         options->diff_path_counter = 0;
4571
4572         if (options->flags.follow_renames && options->pathspec.nr != 1)
4573                 die(_("--follow requires exactly one pathspec"));
4574
4575         if (!options->use_color || external_diff())
4576                 options->color_moved = 0;
4577
4578         FREE_AND_NULL(options->parseopts);
4579 }
4580
4581 static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
4582 {
4583         char c, *eq;
4584         int len;
4585
4586         if (*arg != '-')
4587                 return 0;
4588         c = *++arg;
4589         if (!c)
4590                 return 0;
4591         if (c == arg_short) {
4592                 c = *++arg;
4593                 if (!c)
4594                         return 1;
4595                 if (val && isdigit(c)) {
4596                         char *end;
4597                         int n = strtoul(arg, &end, 10);
4598                         if (*end)
4599                                 return 0;
4600                         *val = n;
4601                         return 1;
4602                 }
4603                 return 0;
4604         }
4605         if (c != '-')
4606                 return 0;
4607         arg++;
4608         eq = strchrnul(arg, '=');
4609         len = eq - arg;
4610         if (!len || strncmp(arg, arg_long, len))
4611                 return 0;
4612         if (*eq) {
4613                 int n;
4614                 char *end;
4615                 if (!isdigit(*++eq))
4616                         return 0;
4617                 n = strtoul(eq, &end, 10);
4618                 if (*end)
4619                         return 0;
4620                 *val = n;
4621         }
4622         return 1;
4623 }
4624
4625 static int diff_scoreopt_parse(const char *opt);
4626
4627 static inline int short_opt(char opt, const char **argv,
4628                             const char **optarg)
4629 {
4630         const char *arg = argv[0];
4631         if (arg[0] != '-' || arg[1] != opt)
4632                 return 0;
4633         if (arg[2] != '\0') {
4634                 *optarg = arg + 2;
4635                 return 1;
4636         }
4637         if (!argv[1])
4638                 die("Option '%c' requires a value", opt);
4639         *optarg = argv[1];
4640         return 2;
4641 }
4642
4643 int parse_long_opt(const char *opt, const char **argv,
4644                    const char **optarg)
4645 {
4646         const char *arg = argv[0];
4647         if (!skip_prefix(arg, "--", &arg))
4648                 return 0;
4649         if (!skip_prefix(arg, opt, &arg))
4650                 return 0;
4651         if (*arg == '=') { /* stuck form: --option=value */
4652                 *optarg = arg + 1;
4653                 return 1;
4654         }
4655         if (*arg != '\0')
4656                 return 0;
4657         /* separate form: --option value */
4658         if (!argv[1])
4659                 die("Option '--%s' requires a value", opt);
4660         *optarg = argv[1];
4661         return 2;
4662 }
4663
4664 static int stat_opt(struct diff_options *options, const char **av)
4665 {
4666         const char *arg = av[0];
4667         char *end;
4668         int width = options->stat_width;
4669         int name_width = options->stat_name_width;
4670         int graph_width = options->stat_graph_width;
4671         int count = options->stat_count;
4672         int argcount = 1;
4673
4674         if (!skip_prefix(arg, "--stat", &arg))
4675                 BUG("stat option does not begin with --stat: %s", arg);
4676         end = (char *)arg;
4677
4678         switch (*arg) {
4679         case '-':
4680                 if (skip_prefix(arg, "-width", &arg)) {
4681                         if (*arg == '=')
4682                                 width = strtoul(arg + 1, &end, 10);
4683                         else if (!*arg && !av[1])
4684                                 die_want_option("--stat-width");
4685                         else if (!*arg) {
4686                                 width = strtoul(av[1], &end, 10);
4687                                 argcount = 2;
4688                         }
4689                 } else if (skip_prefix(arg, "-name-width", &arg)) {
4690                         if (*arg == '=')
4691                                 name_width = strtoul(arg + 1, &end, 10);
4692                         else if (!*arg && !av[1])
4693                                 die_want_option("--stat-name-width");
4694                         else if (!*arg) {
4695                                 name_width = strtoul(av[1], &end, 10);
4696                                 argcount = 2;
4697                         }
4698                 } else if (skip_prefix(arg, "-graph-width", &arg)) {
4699                         if (*arg == '=')
4700                                 graph_width = strtoul(arg + 1, &end, 10);
4701                         else if (!*arg && !av[1])
4702                                 die_want_option("--stat-graph-width");
4703                         else if (!*arg) {
4704                                 graph_width = strtoul(av[1], &end, 10);
4705                                 argcount = 2;
4706                         }
4707                 } else if (skip_prefix(arg, "-count", &arg)) {
4708                         if (*arg == '=')
4709                                 count = strtoul(arg + 1, &end, 10);
4710                         else if (!*arg && !av[1])
4711                                 die_want_option("--stat-count");
4712                         else if (!*arg) {
4713                                 count = strtoul(av[1], &end, 10);
4714                                 argcount = 2;
4715                         }
4716                 }
4717                 break;
4718         case '=':
4719                 width = strtoul(arg+1, &end, 10);
4720                 if (*end == ',')
4721                         name_width = strtoul(end+1, &end, 10);
4722                 if (*end == ',')
4723                         count = strtoul(end+1, &end, 10);
4724         }
4725
4726         /* Important! This checks all the error cases! */
4727         if (*end)
4728                 return 0;
4729         options->output_format |= DIFF_FORMAT_DIFFSTAT;
4730         options->stat_name_width = name_width;
4731         options->stat_graph_width = graph_width;
4732         options->stat_width = width;
4733         options->stat_count = count;
4734         return argcount;
4735 }
4736
4737 static int parse_dirstat_opt(struct diff_options *options, const char *params)
4738 {
4739         struct strbuf errmsg = STRBUF_INIT;
4740         if (parse_dirstat_params(options, params, &errmsg))
4741                 die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
4742                     errmsg.buf);
4743         strbuf_release(&errmsg);
4744         /*
4745          * The caller knows a dirstat-related option is given from the command
4746          * line; allow it to say "return this_function();"
4747          */
4748         options->output_format |= DIFF_FORMAT_DIRSTAT;
4749         return 1;
4750 }
4751
4752 static int parse_submodule_opt(struct diff_options *options, const char *value)
4753 {
4754         if (parse_submodule_params(options, value))
4755                 die(_("Failed to parse --submodule option parameter: '%s'"),
4756                         value);
4757         return 1;
4758 }
4759
4760 static const char diff_status_letters[] = {
4761         DIFF_STATUS_ADDED,
4762         DIFF_STATUS_COPIED,
4763         DIFF_STATUS_DELETED,
4764         DIFF_STATUS_MODIFIED,
4765         DIFF_STATUS_RENAMED,
4766         DIFF_STATUS_TYPE_CHANGED,
4767         DIFF_STATUS_UNKNOWN,
4768         DIFF_STATUS_UNMERGED,
4769         DIFF_STATUS_FILTER_AON,
4770         DIFF_STATUS_FILTER_BROKEN,
4771         '\0',
4772 };
4773
4774 static unsigned int filter_bit['Z' + 1];
4775
4776 static void prepare_filter_bits(void)
4777 {
4778         int i;
4779
4780         if (!filter_bit[DIFF_STATUS_ADDED]) {
4781                 for (i = 0; diff_status_letters[i]; i++)
4782                         filter_bit[(int) diff_status_letters[i]] = (1 << i);
4783         }
4784 }
4785
4786 static unsigned filter_bit_tst(char status, const struct diff_options *opt)
4787 {
4788         return opt->filter & filter_bit[(int) status];
4789 }
4790
4791 static int parse_diff_filter_opt(const char *optarg, struct diff_options *opt)
4792 {
4793         int i, optch;
4794
4795         prepare_filter_bits();
4796
4797         /*
4798          * If there is a negation e.g. 'd' in the input, and we haven't
4799          * initialized the filter field with another --diff-filter, start
4800          * from full set of bits, except for AON.
4801          */
4802         if (!opt->filter) {
4803                 for (i = 0; (optch = optarg[i]) != '\0'; i++) {
4804                         if (optch < 'a' || 'z' < optch)
4805                                 continue;
4806                         opt->filter = (1 << (ARRAY_SIZE(diff_status_letters) - 1)) - 1;
4807                         opt->filter &= ~filter_bit[DIFF_STATUS_FILTER_AON];
4808                         break;
4809                 }
4810         }
4811
4812         for (i = 0; (optch = optarg[i]) != '\0'; i++) {
4813                 unsigned int bit;
4814                 int negate;
4815
4816                 if ('a' <= optch && optch <= 'z') {
4817                         negate = 1;
4818                         optch = toupper(optch);
4819                 } else {
4820                         negate = 0;
4821                 }
4822
4823                 bit = (0 <= optch && optch <= 'Z') ? filter_bit[optch] : 0;
4824                 if (!bit)
4825                         return optarg[i];
4826                 if (negate)
4827                         opt->filter &= ~bit;
4828                 else
4829                         opt->filter |= bit;
4830         }
4831         return 0;
4832 }
4833
4834 static void enable_patch_output(int *fmt)
4835 {
4836         *fmt &= ~DIFF_FORMAT_NO_OUTPUT;
4837         *fmt |= DIFF_FORMAT_PATCH;
4838 }
4839
4840 static int parse_ws_error_highlight_opt(struct diff_options *opt, const char *arg)
4841 {
4842         int val = parse_ws_error_highlight(arg);
4843
4844         if (val < 0) {
4845                 error("unknown value after ws-error-highlight=%.*s",
4846                       -1 - val, arg);
4847                 return 0;
4848         }
4849         opt->ws_error_highlight = val;
4850         return 1;
4851 }
4852
4853 static int parse_objfind_opt(struct diff_options *opt, const char *arg)
4854 {
4855         struct object_id oid;
4856
4857         if (get_oid(arg, &oid))
4858                 return error("unable to resolve '%s'", arg);
4859
4860         if (!opt->objfind)
4861                 opt->objfind = xcalloc(1, sizeof(*opt->objfind));
4862
4863         opt->pickaxe_opts |= DIFF_PICKAXE_KIND_OBJFIND;
4864         opt->flags.recursive = 1;
4865         opt->flags.tree_in_recursive = 1;
4866         oidset_insert(opt->objfind, &oid);
4867         return 1;
4868 }
4869
4870 static int diff_opt_dirstat(const struct option *opt,
4871                             const char *arg, int unset)
4872 {
4873         struct diff_options *options = opt->value;
4874
4875         BUG_ON_OPT_NEG(unset);
4876         if (!strcmp(opt->long_name, "cumulative")) {
4877                 if (arg)
4878                         BUG("how come --cumulative take a value?");
4879                 arg = "cumulative";
4880         } else if (!strcmp(opt->long_name, "dirstat-by-file"))
4881                 parse_dirstat_opt(options, "files");
4882         parse_dirstat_opt(options, arg ? arg : "");
4883         return 0;
4884 }
4885
4886 static int diff_opt_unified(const struct option *opt,
4887                             const char *arg, int unset)
4888 {
4889         struct diff_options *options = opt->value;
4890         char *s;
4891
4892         BUG_ON_OPT_NEG(unset);
4893
4894         options->context = strtol(arg, &s, 10);
4895         if (*s)
4896                 return error(_("%s expects a numerical value"), "--unified");
4897         enable_patch_output(&options->output_format);
4898
4899         return 0;
4900 }
4901
4902 static void prep_parse_options(struct diff_options *options)
4903 {
4904         struct option parseopts[] = {
4905                 OPT_GROUP(N_("Diff output format options")),
4906                 OPT_BITOP('p', "patch", &options->output_format,
4907                           N_("generate patch"),
4908                           DIFF_FORMAT_PATCH, DIFF_FORMAT_NO_OUTPUT),
4909                 OPT_BITOP('u', NULL, &options->output_format,
4910                           N_("generate patch"),
4911                           DIFF_FORMAT_PATCH, DIFF_FORMAT_NO_OUTPUT),
4912                 OPT_CALLBACK_F('U', "unified", options, N_("<n>"),
4913                                N_("generate diffs with <n> lines context"),
4914                                PARSE_OPT_NONEG, diff_opt_unified),
4915                 OPT_BOOL('W', "function-context", &options->flags.funccontext,
4916                          N_("generate diffs with <n> lines context")),
4917                 OPT_BIT_F(0, "raw", &options->output_format,
4918                           N_("generate the diff in raw format"),
4919                           DIFF_FORMAT_RAW, PARSE_OPT_NONEG),
4920                 OPT_BITOP(0, "patch-with-raw", &options->output_format,
4921                           N_("synonym for '-p --raw'"),
4922                           DIFF_FORMAT_PATCH | DIFF_FORMAT_RAW,
4923                           DIFF_FORMAT_NO_OUTPUT),
4924                 OPT_BITOP(0, "patch-with-stat", &options->output_format,
4925                           N_("synonym for '-p --stat'"),
4926                           DIFF_FORMAT_PATCH | DIFF_FORMAT_DIFFSTAT,
4927                           DIFF_FORMAT_NO_OUTPUT),
4928                 OPT_BIT_F(0, "numstat", &options->output_format,
4929                           N_("machine friendly --stat"),
4930                           DIFF_FORMAT_NUMSTAT, PARSE_OPT_NONEG),
4931                 OPT_BIT_F(0, "shortstat", &options->output_format,
4932                           N_("output only the last line of --stat"),
4933                           DIFF_FORMAT_SHORTSTAT, PARSE_OPT_NONEG),
4934                 OPT_CALLBACK_F('X', "dirstat", options, N_("<param1,param2>..."),
4935                                N_("output the distribution of relative amount of changes for each sub-directory"),
4936                                PARSE_OPT_NONEG | PARSE_OPT_OPTARG,
4937                                diff_opt_dirstat),
4938                 OPT_CALLBACK_F(0, "cumulative", options, NULL,
4939                                N_("synonym for --dirstat=cumulative"),
4940                                PARSE_OPT_NONEG | PARSE_OPT_NOARG,
4941                                diff_opt_dirstat),
4942                 OPT_CALLBACK_F(0, "dirstat-by-file", options, N_("<param1,param2>..."),
4943                                N_("synonym for --dirstat=files,param1,param2..."),
4944                                PARSE_OPT_NONEG | PARSE_OPT_OPTARG,
4945                                diff_opt_dirstat),
4946                 OPT_BIT_F(0, "check", &options->output_format,
4947                           N_("warn if changes introduce conflict markers or whitespace errors"),
4948                           DIFF_FORMAT_CHECKDIFF, PARSE_OPT_NONEG),
4949                 OPT_BIT_F(0, "summary", &options->output_format,
4950                           N_("condensed summary such as creations, renames and mode changes"),
4951                           DIFF_FORMAT_SUMMARY, PARSE_OPT_NONEG),
4952                 OPT_BIT_F(0, "name-only", &options->output_format,
4953                           N_("show only names of changed files"),
4954                           DIFF_FORMAT_NAME, PARSE_OPT_NONEG),
4955                 OPT_BIT_F(0, "name-status", &options->output_format,
4956                           N_("show only names and status of changed files"),
4957                           DIFF_FORMAT_NAME_STATUS, PARSE_OPT_NONEG),
4958                 OPT_END()
4959         };
4960
4961         ALLOC_ARRAY(options->parseopts, ARRAY_SIZE(parseopts));
4962         memcpy(options->parseopts, parseopts, sizeof(parseopts));
4963 }
4964
4965 int diff_opt_parse(struct diff_options *options,
4966                    const char **av, int ac, const char *prefix)
4967 {
4968         const char *arg = av[0];
4969         const char *optarg;
4970         int argcount;
4971
4972         if (!prefix)
4973                 prefix = "";
4974
4975         ac = parse_options(ac, av, prefix, options->parseopts, NULL,
4976                            PARSE_OPT_KEEP_DASHDASH |
4977                            PARSE_OPT_KEEP_UNKNOWN |
4978                            PARSE_OPT_NO_INTERNAL_HELP |
4979                            PARSE_OPT_ONE_SHOT |
4980                            PARSE_OPT_STOP_AT_NON_OPTION);
4981
4982         if (ac)
4983                 return ac;
4984
4985         /* Output format options */
4986         if (!strcmp(arg, "-s") || !strcmp(arg, "--no-patch"))
4987                 options->output_format |= DIFF_FORMAT_NO_OUTPUT;
4988         else if (starts_with(arg, "--stat"))
4989                 /* --stat, --stat-width, --stat-name-width, or --stat-count */
4990                 return stat_opt(options, av);
4991         else if (!strcmp(arg, "--compact-summary")) {
4992                  options->flags.stat_with_summary = 1;
4993                  options->output_format |= DIFF_FORMAT_DIFFSTAT;
4994         } else if (!strcmp(arg, "--no-compact-summary"))
4995                  options->flags.stat_with_summary = 0;
4996         else if (skip_prefix(arg, "--output-indicator-new=", &arg))
4997                 options->output_indicators[OUTPUT_INDICATOR_NEW] = arg[0];
4998         else if (skip_prefix(arg, "--output-indicator-old=", &arg))
4999                 options->output_indicators[OUTPUT_INDICATOR_OLD] = arg[0];
5000         else if (skip_prefix(arg, "--output-indicator-context=", &arg))
5001                 options->output_indicators[OUTPUT_INDICATOR_CONTEXT] = arg[0];
5002
5003         /* renames options */
5004         else if (starts_with(arg, "-B") ||
5005                  skip_to_optional_arg(arg, "--break-rewrites", NULL)) {
5006                 if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
5007                         return error("invalid argument to -B: %s", arg+2);
5008         }
5009         else if (starts_with(arg, "-M") ||
5010                  skip_to_optional_arg(arg, "--find-renames", NULL)) {
5011                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
5012                         return error("invalid argument to -M: %s", arg+2);
5013                 options->detect_rename = DIFF_DETECT_RENAME;
5014         }
5015         else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
5016                 options->irreversible_delete = 1;
5017         }
5018         else if (starts_with(arg, "-C") ||
5019                  skip_to_optional_arg(arg, "--find-copies", NULL)) {
5020                 if (options->detect_rename == DIFF_DETECT_COPY)
5021                         options->flags.find_copies_harder = 1;
5022                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
5023                         return error("invalid argument to -C: %s", arg+2);
5024                 options->detect_rename = DIFF_DETECT_COPY;
5025         }
5026         else if (!strcmp(arg, "--no-renames"))
5027                 options->detect_rename = 0;
5028         else if (!strcmp(arg, "--rename-empty"))
5029                 options->flags.rename_empty = 1;
5030         else if (!strcmp(arg, "--no-rename-empty"))
5031                 options->flags.rename_empty = 0;
5032         else if (skip_to_optional_arg_default(arg, "--relative", &arg, NULL)) {
5033                 options->flags.relative_name = 1;
5034                 if (arg)
5035                         options->prefix = arg;
5036         }
5037
5038         /* xdiff options */
5039         else if (!strcmp(arg, "--minimal"))
5040                 DIFF_XDL_SET(options, NEED_MINIMAL);
5041         else if (!strcmp(arg, "--no-minimal"))
5042                 DIFF_XDL_CLR(options, NEED_MINIMAL);
5043         else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
5044                 DIFF_XDL_SET(options, IGNORE_WHITESPACE);
5045         else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
5046                 DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
5047         else if (!strcmp(arg, "--ignore-space-at-eol"))
5048                 DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
5049         else if (!strcmp(arg, "--ignore-cr-at-eol"))
5050                 DIFF_XDL_SET(options, IGNORE_CR_AT_EOL);
5051         else if (!strcmp(arg, "--ignore-blank-lines"))
5052                 DIFF_XDL_SET(options, IGNORE_BLANK_LINES);
5053         else if (!strcmp(arg, "--indent-heuristic"))
5054                 DIFF_XDL_SET(options, INDENT_HEURISTIC);
5055         else if (!strcmp(arg, "--no-indent-heuristic"))
5056                 DIFF_XDL_CLR(options, INDENT_HEURISTIC);
5057         else if (!strcmp(arg, "--patience")) {
5058                 int i;
5059                 options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
5060                 /*
5061                  * Both --patience and --anchored use PATIENCE_DIFF
5062                  * internally, so remove any anchors previously
5063                  * specified.
5064                  */
5065                 for (i = 0; i < options->anchors_nr; i++)
5066                         free(options->anchors[i]);
5067                 options->anchors_nr = 0;
5068         } else if (!strcmp(arg, "--histogram"))
5069                 options->xdl_opts = DIFF_WITH_ALG(options, HISTOGRAM_DIFF);
5070         else if ((argcount = parse_long_opt("diff-algorithm", av, &optarg))) {
5071                 long value = parse_algorithm_value(optarg);
5072                 if (value < 0)
5073                         return error("option diff-algorithm accepts \"myers\", "
5074                                      "\"minimal\", \"patience\" and \"histogram\"");
5075                 /* clear out previous settings */
5076                 DIFF_XDL_CLR(options, NEED_MINIMAL);
5077                 options->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
5078                 options->xdl_opts |= value;
5079                 return argcount;
5080         } else if (skip_prefix(arg, "--anchored=", &arg)) {
5081                 options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
5082                 ALLOC_GROW(options->anchors, options->anchors_nr + 1,
5083                            options->anchors_alloc);
5084                 options->anchors[options->anchors_nr++] = xstrdup(arg);
5085         }
5086
5087         /* flags options */
5088         else if (!strcmp(arg, "--binary")) {
5089                 enable_patch_output(&options->output_format);
5090                 options->flags.binary = 1;
5091         }
5092         else if (!strcmp(arg, "--full-index"))
5093                 options->flags.full_index = 1;
5094         else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
5095                 options->flags.text = 1;
5096         else if (!strcmp(arg, "-R"))
5097                 options->flags.reverse_diff = 1;
5098         else if (!strcmp(arg, "--find-copies-harder"))
5099                 options->flags.find_copies_harder = 1;
5100         else if (!strcmp(arg, "--follow"))
5101                 options->flags.follow_renames = 1;
5102         else if (!strcmp(arg, "--no-follow")) {
5103                 options->flags.follow_renames = 0;
5104                 options->flags.default_follow_renames = 0;
5105         } else if (skip_to_optional_arg_default(arg, "--color", &arg, "always")) {
5106                 int value = git_config_colorbool(NULL, arg);
5107                 if (value < 0)
5108                         return error("option `color' expects \"always\", \"auto\", or \"never\"");
5109                 options->use_color = value;
5110         }
5111         else if (!strcmp(arg, "--no-color"))
5112                 options->use_color = 0;
5113         else if (!strcmp(arg, "--color-moved")) {
5114                 if (diff_color_moved_default)
5115                         options->color_moved = diff_color_moved_default;
5116                 if (options->color_moved == COLOR_MOVED_NO)
5117                         options->color_moved = COLOR_MOVED_DEFAULT;
5118         } else if (!strcmp(arg, "--no-color-moved"))
5119                 options->color_moved = COLOR_MOVED_NO;
5120         else if (skip_prefix(arg, "--color-moved=", &arg)) {
5121                 int cm = parse_color_moved(arg);
5122                 if (cm < 0)
5123                         return error("bad --color-moved argument: %s", arg);
5124                 options->color_moved = cm;
5125         } else if (skip_prefix(arg, "--color-moved-ws=", &arg)) {
5126                 unsigned cm = parse_color_moved_ws(arg);
5127                 if (cm & COLOR_MOVED_WS_ERROR)
5128                         return -1;
5129                 options->color_moved_ws_handling = cm;
5130         } else if (skip_to_optional_arg_default(arg, "--color-words", &options->word_regex, NULL)) {
5131                 options->use_color = 1;
5132                 options->word_diff = DIFF_WORDS_COLOR;
5133         }
5134         else if (!strcmp(arg, "--word-diff")) {
5135                 if (options->word_diff == DIFF_WORDS_NONE)
5136                         options->word_diff = DIFF_WORDS_PLAIN;
5137         }
5138         else if (skip_prefix(arg, "--word-diff=", &arg)) {
5139                 if (!strcmp(arg, "plain"))
5140                         options->word_diff = DIFF_WORDS_PLAIN;
5141                 else if (!strcmp(arg, "color")) {
5142                         options->use_color = 1;
5143                         options->word_diff = DIFF_WORDS_COLOR;
5144                 }
5145                 else if (!strcmp(arg, "porcelain"))
5146                         options->word_diff = DIFF_WORDS_PORCELAIN;
5147                 else if (!strcmp(arg, "none"))
5148                         options->word_diff = DIFF_WORDS_NONE;
5149                 else
5150                         die("bad --word-diff argument: %s", arg);
5151         }
5152         else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
5153                 if (options->word_diff == DIFF_WORDS_NONE)
5154                         options->word_diff = DIFF_WORDS_PLAIN;
5155                 options->word_regex = optarg;
5156                 return argcount;
5157         }
5158         else if (!strcmp(arg, "--exit-code"))
5159                 options->flags.exit_with_status = 1;
5160         else if (!strcmp(arg, "--quiet"))
5161                 options->flags.quick = 1;
5162         else if (!strcmp(arg, "--ext-diff"))
5163                 options->flags.allow_external = 1;
5164         else if (!strcmp(arg, "--no-ext-diff"))
5165                 options->flags.allow_external = 0;
5166         else if (!strcmp(arg, "--textconv")) {
5167                 options->flags.allow_textconv = 1;
5168                 options->flags.textconv_set_via_cmdline = 1;
5169         } else if (!strcmp(arg, "--no-textconv"))
5170                 options->flags.allow_textconv = 0;
5171         else if (skip_to_optional_arg_default(arg, "--ignore-submodules", &arg, "all")) {
5172                 options->flags.override_submodule_config = 1;
5173                 handle_ignore_submodules_arg(options, arg);
5174         } else if (skip_to_optional_arg_default(arg, "--submodule", &arg, "log"))
5175                 return parse_submodule_opt(options, arg);
5176         else if (skip_prefix(arg, "--ws-error-highlight=", &arg))
5177                 return parse_ws_error_highlight_opt(options, arg);
5178         else if (!strcmp(arg, "--ita-invisible-in-index"))
5179                 options->ita_invisible_in_index = 1;
5180         else if (!strcmp(arg, "--ita-visible-in-index"))
5181                 options->ita_invisible_in_index = 0;
5182
5183         /* misc options */
5184         else if (!strcmp(arg, "-z"))
5185                 options->line_termination = 0;
5186         else if ((argcount = short_opt('l', av, &optarg))) {
5187                 options->rename_limit = strtoul(optarg, NULL, 10);
5188                 return argcount;
5189         }
5190         else if ((argcount = short_opt('S', av, &optarg))) {
5191                 options->pickaxe = optarg;
5192                 options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
5193                 return argcount;
5194         } else if ((argcount = short_opt('G', av, &optarg))) {
5195                 options->pickaxe = optarg;
5196                 options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
5197                 return argcount;
5198         }
5199         else if (!strcmp(arg, "--pickaxe-all"))
5200                 options->pickaxe_opts |= DIFF_PICKAXE_ALL;
5201         else if (!strcmp(arg, "--pickaxe-regex"))
5202                 options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
5203         else if ((argcount = short_opt('O', av, &optarg))) {
5204                 options->orderfile = prefix_filename(prefix, optarg);
5205                 return argcount;
5206         } else if (skip_prefix(arg, "--find-object=", &arg))
5207                 return parse_objfind_opt(options, arg);
5208         else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
5209                 int offending = parse_diff_filter_opt(optarg, options);
5210                 if (offending)
5211                         die("unknown change class '%c' in --diff-filter=%s",
5212                             offending, optarg);
5213                 return argcount;
5214         }
5215         else if (!strcmp(arg, "--no-abbrev"))
5216                 options->abbrev = 0;
5217         else if (!strcmp(arg, "--abbrev"))
5218                 options->abbrev = DEFAULT_ABBREV;
5219         else if (skip_prefix(arg, "--abbrev=", &arg)) {
5220                 options->abbrev = strtoul(arg, NULL, 10);
5221                 if (options->abbrev < MINIMUM_ABBREV)
5222                         options->abbrev = MINIMUM_ABBREV;
5223                 else if (the_hash_algo->hexsz < options->abbrev)
5224                         options->abbrev = the_hash_algo->hexsz;
5225         }
5226         else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
5227                 options->a_prefix = optarg;
5228                 return argcount;
5229         }
5230         else if ((argcount = parse_long_opt("line-prefix", av, &optarg))) {
5231                 options->line_prefix = optarg;
5232                 options->line_prefix_length = strlen(options->line_prefix);
5233                 graph_setup_line_prefix(options);
5234                 return argcount;
5235         }
5236         else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
5237                 options->b_prefix = optarg;
5238                 return argcount;
5239         }
5240         else if (!strcmp(arg, "--no-prefix"))
5241                 options->a_prefix = options->b_prefix = "";
5242         else if (opt_arg(arg, '\0', "inter-hunk-context",
5243                          &options->interhunkcontext))
5244                 ;
5245         else if ((argcount = parse_long_opt("output", av, &optarg))) {
5246                 char *path = prefix_filename(prefix, optarg);
5247                 options->file = xfopen(path, "w");
5248                 options->close_file = 1;
5249                 if (options->use_color != GIT_COLOR_ALWAYS)
5250                         options->use_color = GIT_COLOR_NEVER;
5251                 free(path);
5252                 return argcount;
5253         } else
5254                 return 0;
5255         return 1;
5256 }
5257
5258 int parse_rename_score(const char **cp_p)
5259 {
5260         unsigned long num, scale;
5261         int ch, dot;
5262         const char *cp = *cp_p;
5263
5264         num = 0;
5265         scale = 1;
5266         dot = 0;
5267         for (;;) {
5268                 ch = *cp;
5269                 if ( !dot && ch == '.' ) {
5270                         scale = 1;
5271                         dot = 1;
5272                 } else if ( ch == '%' ) {
5273                         scale = dot ? scale*100 : 100;
5274                         cp++;   /* % is always at the end */
5275                         break;
5276                 } else if ( ch >= '0' && ch <= '9' ) {
5277                         if ( scale < 100000 ) {
5278                                 scale *= 10;
5279                                 num = (num*10) + (ch-'0');
5280                         }
5281                 } else {
5282                         break;
5283                 }
5284                 cp++;
5285         }
5286         *cp_p = cp;
5287
5288         /* user says num divided by scale and we say internally that
5289          * is MAX_SCORE * num / scale.
5290          */
5291         return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
5292 }
5293
5294 static int diff_scoreopt_parse(const char *opt)
5295 {
5296         int opt1, opt2, cmd;
5297
5298         if (*opt++ != '-')
5299                 return -1;
5300         cmd = *opt++;
5301         if (cmd == '-') {
5302                 /* convert the long-form arguments into short-form versions */
5303                 if (skip_prefix(opt, "break-rewrites", &opt)) {
5304                         if (*opt == 0 || *opt++ == '=')
5305                                 cmd = 'B';
5306                 } else if (skip_prefix(opt, "find-copies", &opt)) {
5307                         if (*opt == 0 || *opt++ == '=')
5308                                 cmd = 'C';
5309                 } else if (skip_prefix(opt, "find-renames", &opt)) {
5310                         if (*opt == 0 || *opt++ == '=')
5311                                 cmd = 'M';
5312                 }
5313         }
5314         if (cmd != 'M' && cmd != 'C' && cmd != 'B')
5315                 return -1; /* that is not a -M, -C, or -B option */
5316
5317         opt1 = parse_rename_score(&opt);
5318         if (cmd != 'B')
5319                 opt2 = 0;
5320         else {
5321                 if (*opt == 0)
5322                         opt2 = 0;
5323                 else if (*opt != '/')
5324                         return -1; /* we expect -B80/99 or -B80 */
5325                 else {
5326                         opt++;
5327                         opt2 = parse_rename_score(&opt);
5328                 }
5329         }
5330         if (*opt != 0)
5331                 return -1;
5332         return opt1 | (opt2 << 16);
5333 }
5334
5335 struct diff_queue_struct diff_queued_diff;
5336
5337 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
5338 {
5339         ALLOC_GROW(queue->queue, queue->nr + 1, queue->alloc);
5340         queue->queue[queue->nr++] = dp;
5341 }
5342
5343 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
5344                                  struct diff_filespec *one,
5345                                  struct diff_filespec *two)
5346 {
5347         struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
5348         dp->one = one;
5349         dp->two = two;
5350         if (queue)
5351                 diff_q(queue, dp);
5352         return dp;
5353 }
5354
5355 void diff_free_filepair(struct diff_filepair *p)
5356 {
5357         free_filespec(p->one);
5358         free_filespec(p->two);
5359         free(p);
5360 }
5361
5362 const char *diff_aligned_abbrev(const struct object_id *oid, int len)
5363 {
5364         int abblen;
5365         const char *abbrev;
5366
5367         /* Do we want all 40 hex characters? */
5368         if (len == the_hash_algo->hexsz)
5369                 return oid_to_hex(oid);
5370
5371         /* An abbreviated value is fine, possibly followed by an ellipsis. */
5372         abbrev = diff_abbrev_oid(oid, len);
5373
5374         if (!print_sha1_ellipsis())
5375                 return abbrev;
5376
5377         abblen = strlen(abbrev);
5378
5379         /*
5380          * In well-behaved cases, where the abbreviated result is the
5381          * same as the requested length, append three dots after the
5382          * abbreviation (hence the whole logic is limited to the case
5383          * where abblen < 37); when the actual abbreviated result is a
5384          * bit longer than the requested length, we reduce the number
5385          * of dots so that they match the well-behaved ones.  However,
5386          * if the actual abbreviation is longer than the requested
5387          * length by more than three, we give up on aligning, and add
5388          * three dots anyway, to indicate that the output is not the
5389          * full object name.  Yes, this may be suboptimal, but this
5390          * appears only in "diff --raw --abbrev" output and it is not
5391          * worth the effort to change it now.  Note that this would
5392          * likely to work fine when the automatic sizing of default
5393          * abbreviation length is used--we would be fed -1 in "len" in
5394          * that case, and will end up always appending three-dots, but
5395          * the automatic sizing is supposed to give abblen that ensures
5396          * uniqueness across all objects (statistically speaking).
5397          */
5398         if (abblen < the_hash_algo->hexsz - 3) {
5399                 static char hex[GIT_MAX_HEXSZ + 1];
5400                 if (len < abblen && abblen <= len + 2)
5401                         xsnprintf(hex, sizeof(hex), "%s%.*s", abbrev, len+3-abblen, "..");
5402                 else
5403                         xsnprintf(hex, sizeof(hex), "%s...", abbrev);
5404                 return hex;
5405         }
5406
5407         return oid_to_hex(oid);
5408 }
5409
5410 static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
5411 {
5412         int line_termination = opt->line_termination;
5413         int inter_name_termination = line_termination ? '\t' : '\0';
5414
5415         fprintf(opt->file, "%s", diff_line_prefix(opt));
5416         if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
5417                 fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
5418                         diff_aligned_abbrev(&p->one->oid, opt->abbrev));
5419                 fprintf(opt->file, "%s ",
5420                         diff_aligned_abbrev(&p->two->oid, opt->abbrev));
5421         }
5422         if (p->score) {
5423                 fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
5424                         inter_name_termination);
5425         } else {
5426                 fprintf(opt->file, "%c%c", p->status, inter_name_termination);
5427         }
5428
5429         if (p->status == DIFF_STATUS_COPIED ||
5430             p->status == DIFF_STATUS_RENAMED) {
5431                 const char *name_a, *name_b;
5432                 name_a = p->one->path;
5433                 name_b = p->two->path;
5434                 strip_prefix(opt->prefix_length, &name_a, &name_b);
5435                 write_name_quoted(name_a, opt->file, inter_name_termination);
5436                 write_name_quoted(name_b, opt->file, line_termination);
5437         } else {
5438                 const char *name_a, *name_b;
5439                 name_a = p->one->mode ? p->one->path : p->two->path;
5440                 name_b = NULL;
5441                 strip_prefix(opt->prefix_length, &name_a, &name_b);
5442                 write_name_quoted(name_a, opt->file, line_termination);
5443         }
5444 }
5445
5446 int diff_unmodified_pair(struct diff_filepair *p)
5447 {
5448         /* This function is written stricter than necessary to support
5449          * the currently implemented transformers, but the idea is to
5450          * let transformers to produce diff_filepairs any way they want,
5451          * and filter and clean them up here before producing the output.
5452          */
5453         struct diff_filespec *one = p->one, *two = p->two;
5454
5455         if (DIFF_PAIR_UNMERGED(p))
5456                 return 0; /* unmerged is interesting */
5457
5458         /* deletion, addition, mode or type change
5459          * and rename are all interesting.
5460          */
5461         if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
5462             DIFF_PAIR_MODE_CHANGED(p) ||
5463             strcmp(one->path, two->path))
5464                 return 0;
5465
5466         /* both are valid and point at the same path.  that is, we are
5467          * dealing with a change.
5468          */
5469         if (one->oid_valid && two->oid_valid &&
5470             oideq(&one->oid, &two->oid) &&
5471             !one->dirty_submodule && !two->dirty_submodule)
5472                 return 1; /* no change */
5473         if (!one->oid_valid && !two->oid_valid)
5474                 return 1; /* both look at the same file on the filesystem. */
5475         return 0;
5476 }
5477
5478 static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
5479 {
5480         if (diff_unmodified_pair(p))
5481                 return;
5482
5483         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5484             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5485                 return; /* no tree diffs in patch format */
5486
5487         run_diff(p, o);
5488 }
5489
5490 static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
5491                             struct diffstat_t *diffstat)
5492 {
5493         if (diff_unmodified_pair(p))
5494                 return;
5495
5496         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5497             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5498                 return; /* no useful stat for tree diffs */
5499
5500         run_diffstat(p, o, diffstat);
5501 }
5502
5503 static void diff_flush_checkdiff(struct diff_filepair *p,
5504                 struct diff_options *o)
5505 {
5506         if (diff_unmodified_pair(p))
5507                 return;
5508
5509         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5510             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5511                 return; /* nothing to check in tree diffs */
5512
5513         run_checkdiff(p, o);
5514 }
5515
5516 int diff_queue_is_empty(void)
5517 {
5518         struct diff_queue_struct *q = &diff_queued_diff;
5519         int i;
5520         for (i = 0; i < q->nr; i++)
5521                 if (!diff_unmodified_pair(q->queue[i]))
5522                         return 0;
5523         return 1;
5524 }
5525
5526 #if DIFF_DEBUG
5527 void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
5528 {
5529         fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
5530                 x, one ? one : "",
5531                 s->path,
5532                 DIFF_FILE_VALID(s) ? "valid" : "invalid",
5533                 s->mode,
5534                 s->oid_valid ? oid_to_hex(&s->oid) : "");
5535         fprintf(stderr, "queue[%d] %s size %lu\n",
5536                 x, one ? one : "",
5537                 s->size);
5538 }
5539
5540 void diff_debug_filepair(const struct diff_filepair *p, int i)
5541 {
5542         diff_debug_filespec(p->one, i, "one");
5543         diff_debug_filespec(p->two, i, "two");
5544         fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
5545                 p->score, p->status ? p->status : '?',
5546                 p->one->rename_used, p->broken_pair);
5547 }
5548
5549 void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
5550 {
5551         int i;
5552         if (msg)
5553                 fprintf(stderr, "%s\n", msg);
5554         fprintf(stderr, "q->nr = %d\n", q->nr);
5555         for (i = 0; i < q->nr; i++) {
5556                 struct diff_filepair *p = q->queue[i];
5557                 diff_debug_filepair(p, i);
5558         }
5559 }
5560 #endif
5561
5562 static void diff_resolve_rename_copy(void)
5563 {
5564         int i;
5565         struct diff_filepair *p;
5566         struct diff_queue_struct *q = &diff_queued_diff;
5567
5568         diff_debug_queue("resolve-rename-copy", q);
5569
5570         for (i = 0; i < q->nr; i++) {
5571                 p = q->queue[i];
5572                 p->status = 0; /* undecided */
5573                 if (DIFF_PAIR_UNMERGED(p))
5574                         p->status = DIFF_STATUS_UNMERGED;
5575                 else if (!DIFF_FILE_VALID(p->one))
5576                         p->status = DIFF_STATUS_ADDED;
5577                 else if (!DIFF_FILE_VALID(p->two))
5578                         p->status = DIFF_STATUS_DELETED;
5579                 else if (DIFF_PAIR_TYPE_CHANGED(p))
5580                         p->status = DIFF_STATUS_TYPE_CHANGED;
5581
5582                 /* from this point on, we are dealing with a pair
5583                  * whose both sides are valid and of the same type, i.e.
5584                  * either in-place edit or rename/copy edit.
5585                  */
5586                 else if (DIFF_PAIR_RENAME(p)) {
5587                         /*
5588                          * A rename might have re-connected a broken
5589                          * pair up, causing the pathnames to be the
5590                          * same again. If so, that's not a rename at
5591                          * all, just a modification..
5592                          *
5593                          * Otherwise, see if this source was used for
5594                          * multiple renames, in which case we decrement
5595                          * the count, and call it a copy.
5596                          */
5597                         if (!strcmp(p->one->path, p->two->path))
5598                                 p->status = DIFF_STATUS_MODIFIED;
5599                         else if (--p->one->rename_used > 0)
5600                                 p->status = DIFF_STATUS_COPIED;
5601                         else
5602                                 p->status = DIFF_STATUS_RENAMED;
5603                 }
5604                 else if (!oideq(&p->one->oid, &p->two->oid) ||
5605                          p->one->mode != p->two->mode ||
5606                          p->one->dirty_submodule ||
5607                          p->two->dirty_submodule ||
5608                          is_null_oid(&p->one->oid))
5609                         p->status = DIFF_STATUS_MODIFIED;
5610                 else {
5611                         /* This is a "no-change" entry and should not
5612                          * happen anymore, but prepare for broken callers.
5613                          */
5614                         error("feeding unmodified %s to diffcore",
5615                               p->one->path);
5616                         p->status = DIFF_STATUS_UNKNOWN;
5617                 }
5618         }
5619         diff_debug_queue("resolve-rename-copy done", q);
5620 }
5621
5622 static int check_pair_status(struct diff_filepair *p)
5623 {
5624         switch (p->status) {
5625         case DIFF_STATUS_UNKNOWN:
5626                 return 0;
5627         case 0:
5628                 die("internal error in diff-resolve-rename-copy");
5629         default:
5630                 return 1;
5631         }
5632 }
5633
5634 static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
5635 {
5636         int fmt = opt->output_format;
5637
5638         if (fmt & DIFF_FORMAT_CHECKDIFF)
5639                 diff_flush_checkdiff(p, opt);
5640         else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
5641                 diff_flush_raw(p, opt);
5642         else if (fmt & DIFF_FORMAT_NAME) {
5643                 const char *name_a, *name_b;
5644                 name_a = p->two->path;
5645                 name_b = NULL;
5646                 strip_prefix(opt->prefix_length, &name_a, &name_b);
5647                 fprintf(opt->file, "%s", diff_line_prefix(opt));
5648                 write_name_quoted(name_a, opt->file, opt->line_termination);
5649         }
5650 }
5651
5652 static void show_file_mode_name(struct diff_options *opt, const char *newdelete, struct diff_filespec *fs)
5653 {
5654         struct strbuf sb = STRBUF_INIT;
5655         if (fs->mode)
5656                 strbuf_addf(&sb, " %s mode %06o ", newdelete, fs->mode);
5657         else
5658                 strbuf_addf(&sb, " %s ", newdelete);
5659
5660         quote_c_style(fs->path, &sb, NULL, 0);
5661         strbuf_addch(&sb, '\n');
5662         emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5663                          sb.buf, sb.len, 0);
5664         strbuf_release(&sb);
5665 }
5666
5667 static void show_mode_change(struct diff_options *opt, struct diff_filepair *p,
5668                 int show_name)
5669 {
5670         if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
5671                 struct strbuf sb = STRBUF_INIT;
5672                 strbuf_addf(&sb, " mode change %06o => %06o",
5673                             p->one->mode, p->two->mode);
5674                 if (show_name) {
5675                         strbuf_addch(&sb, ' ');
5676                         quote_c_style(p->two->path, &sb, NULL, 0);
5677                 }
5678                 strbuf_addch(&sb, '\n');
5679                 emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5680                                  sb.buf, sb.len, 0);
5681                 strbuf_release(&sb);
5682         }
5683 }
5684
5685 static void show_rename_copy(struct diff_options *opt, const char *renamecopy,
5686                 struct diff_filepair *p)
5687 {
5688         struct strbuf sb = STRBUF_INIT;
5689         struct strbuf names = STRBUF_INIT;
5690
5691         pprint_rename(&names, p->one->path, p->two->path);
5692         strbuf_addf(&sb, " %s %s (%d%%)\n",
5693                     renamecopy, names.buf, similarity_index(p));
5694         strbuf_release(&names);
5695         emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5696                                  sb.buf, sb.len, 0);
5697         show_mode_change(opt, p, 0);
5698         strbuf_release(&sb);
5699 }
5700
5701 static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
5702 {
5703         switch(p->status) {
5704         case DIFF_STATUS_DELETED:
5705                 show_file_mode_name(opt, "delete", p->one);
5706                 break;
5707         case DIFF_STATUS_ADDED:
5708                 show_file_mode_name(opt, "create", p->two);
5709                 break;
5710         case DIFF_STATUS_COPIED:
5711                 show_rename_copy(opt, "copy", p);
5712                 break;
5713         case DIFF_STATUS_RENAMED:
5714                 show_rename_copy(opt, "rename", p);
5715                 break;
5716         default:
5717                 if (p->score) {
5718                         struct strbuf sb = STRBUF_INIT;
5719                         strbuf_addstr(&sb, " rewrite ");
5720                         quote_c_style(p->two->path, &sb, NULL, 0);
5721                         strbuf_addf(&sb, " (%d%%)\n", similarity_index(p));
5722                         emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5723                                          sb.buf, sb.len, 0);
5724                         strbuf_release(&sb);
5725                 }
5726                 show_mode_change(opt, p, !p->score);
5727                 break;
5728         }
5729 }
5730
5731 struct patch_id_t {
5732         git_SHA_CTX *ctx;
5733         int patchlen;
5734 };
5735
5736 static int remove_space(char *line, int len)
5737 {
5738         int i;
5739         char *dst = line;
5740         unsigned char c;
5741
5742         for (i = 0; i < len; i++)
5743                 if (!isspace((c = line[i])))
5744                         *dst++ = c;
5745
5746         return dst - line;
5747 }
5748
5749 static void patch_id_consume(void *priv, char *line, unsigned long len)
5750 {
5751         struct patch_id_t *data = priv;
5752         int new_len;
5753
5754         new_len = remove_space(line, len);
5755
5756         git_SHA1_Update(data->ctx, line, new_len);
5757         data->patchlen += new_len;
5758 }
5759
5760 static void patch_id_add_string(git_SHA_CTX *ctx, const char *str)
5761 {
5762         git_SHA1_Update(ctx, str, strlen(str));
5763 }
5764
5765 static void patch_id_add_mode(git_SHA_CTX *ctx, unsigned mode)
5766 {
5767         /* large enough for 2^32 in octal */
5768         char buf[12];
5769         int len = xsnprintf(buf, sizeof(buf), "%06o", mode);
5770         git_SHA1_Update(ctx, buf, len);
5771 }
5772
5773 /* returns 0 upon success, and writes result into sha1 */
5774 static int diff_get_patch_id(struct diff_options *options, struct object_id *oid, int diff_header_only)
5775 {
5776         struct diff_queue_struct *q = &diff_queued_diff;
5777         int i;
5778         git_SHA_CTX ctx;
5779         struct patch_id_t data;
5780
5781         git_SHA1_Init(&ctx);
5782         memset(&data, 0, sizeof(struct patch_id_t));
5783         data.ctx = &ctx;
5784
5785         for (i = 0; i < q->nr; i++) {
5786                 xpparam_t xpp;
5787                 xdemitconf_t xecfg;
5788                 mmfile_t mf1, mf2;
5789                 struct diff_filepair *p = q->queue[i];
5790                 int len1, len2;
5791
5792                 memset(&xpp, 0, sizeof(xpp));
5793                 memset(&xecfg, 0, sizeof(xecfg));
5794                 if (p->status == 0)
5795                         return error("internal diff status error");
5796                 if (p->status == DIFF_STATUS_UNKNOWN)
5797                         continue;
5798                 if (diff_unmodified_pair(p))
5799                         continue;
5800                 if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5801                     (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5802                         continue;
5803                 if (DIFF_PAIR_UNMERGED(p))
5804                         continue;
5805
5806                 diff_fill_oid_info(p->one, options->repo->index);
5807                 diff_fill_oid_info(p->two, options->repo->index);
5808
5809                 len1 = remove_space(p->one->path, strlen(p->one->path));
5810                 len2 = remove_space(p->two->path, strlen(p->two->path));
5811                 patch_id_add_string(&ctx, "diff--git");
5812                 patch_id_add_string(&ctx, "a/");
5813                 git_SHA1_Update(&ctx, p->one->path, len1);
5814                 patch_id_add_string(&ctx, "b/");
5815                 git_SHA1_Update(&ctx, p->two->path, len2);
5816
5817                 if (p->one->mode == 0) {
5818                         patch_id_add_string(&ctx, "newfilemode");
5819                         patch_id_add_mode(&ctx, p->two->mode);
5820                         patch_id_add_string(&ctx, "---/dev/null");
5821                         patch_id_add_string(&ctx, "+++b/");
5822                         git_SHA1_Update(&ctx, p->two->path, len2);
5823                 } else if (p->two->mode == 0) {
5824                         patch_id_add_string(&ctx, "deletedfilemode");
5825                         patch_id_add_mode(&ctx, p->one->mode);
5826                         patch_id_add_string(&ctx, "---a/");
5827                         git_SHA1_Update(&ctx, p->one->path, len1);
5828                         patch_id_add_string(&ctx, "+++/dev/null");
5829                 } else {
5830                         patch_id_add_string(&ctx, "---a/");
5831                         git_SHA1_Update(&ctx, p->one->path, len1);
5832                         patch_id_add_string(&ctx, "+++b/");
5833                         git_SHA1_Update(&ctx, p->two->path, len2);
5834                 }
5835
5836                 if (diff_header_only)
5837                         continue;
5838
5839                 if (fill_mmfile(options->repo, &mf1, p->one) < 0 ||
5840                     fill_mmfile(options->repo, &mf2, p->two) < 0)
5841                         return error("unable to read files to diff");
5842
5843                 if (diff_filespec_is_binary(options->repo, p->one) ||
5844                     diff_filespec_is_binary(options->repo, p->two)) {
5845                         git_SHA1_Update(&ctx, oid_to_hex(&p->one->oid),
5846                                         GIT_SHA1_HEXSZ);
5847                         git_SHA1_Update(&ctx, oid_to_hex(&p->two->oid),
5848                                         GIT_SHA1_HEXSZ);
5849                         continue;
5850                 }
5851
5852                 xpp.flags = 0;
5853                 xecfg.ctxlen = 3;
5854                 xecfg.flags = 0;
5855                 if (xdi_diff_outf(&mf1, &mf2, discard_hunk_line,
5856                                   patch_id_consume, &data, &xpp, &xecfg))
5857                         return error("unable to generate patch-id diff for %s",
5858                                      p->one->path);
5859         }
5860
5861         git_SHA1_Final(oid->hash, &ctx);
5862         return 0;
5863 }
5864
5865 int diff_flush_patch_id(struct diff_options *options, struct object_id *oid, int diff_header_only)
5866 {
5867         struct diff_queue_struct *q = &diff_queued_diff;
5868         int i;
5869         int result = diff_get_patch_id(options, oid, diff_header_only);
5870
5871         for (i = 0; i < q->nr; i++)
5872                 diff_free_filepair(q->queue[i]);
5873
5874         free(q->queue);
5875         DIFF_QUEUE_CLEAR(q);
5876
5877         return result;
5878 }
5879
5880 static int is_summary_empty(const struct diff_queue_struct *q)
5881 {
5882         int i;
5883
5884         for (i = 0; i < q->nr; i++) {
5885                 const struct diff_filepair *p = q->queue[i];
5886
5887                 switch (p->status) {
5888                 case DIFF_STATUS_DELETED:
5889                 case DIFF_STATUS_ADDED:
5890                 case DIFF_STATUS_COPIED:
5891                 case DIFF_STATUS_RENAMED:
5892                         return 0;
5893                 default:
5894                         if (p->score)
5895                                 return 0;
5896                         if (p->one->mode && p->two->mode &&
5897                             p->one->mode != p->two->mode)
5898                                 return 0;
5899                         break;
5900                 }
5901         }
5902         return 1;
5903 }
5904
5905 static const char rename_limit_warning[] =
5906 N_("inexact rename detection was skipped due to too many files.");
5907
5908 static const char degrade_cc_to_c_warning[] =
5909 N_("only found copies from modified paths due to too many files.");
5910
5911 static const char rename_limit_advice[] =
5912 N_("you may want to set your %s variable to at least "
5913    "%d and retry the command.");
5914
5915 void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
5916 {
5917         fflush(stdout);
5918         if (degraded_cc)
5919                 warning(_(degrade_cc_to_c_warning));
5920         else if (needed)
5921                 warning(_(rename_limit_warning));
5922         else
5923                 return;
5924         if (0 < needed)
5925                 warning(_(rename_limit_advice), varname, needed);
5926 }
5927
5928 static void diff_flush_patch_all_file_pairs(struct diff_options *o)
5929 {
5930         int i;
5931         static struct emitted_diff_symbols esm = EMITTED_DIFF_SYMBOLS_INIT;
5932         struct diff_queue_struct *q = &diff_queued_diff;
5933
5934         if (WSEH_NEW & WS_RULE_MASK)
5935                 BUG("WS rules bit mask overlaps with diff symbol flags");
5936
5937         if (o->color_moved)
5938                 o->emitted_symbols = &esm;
5939
5940         for (i = 0; i < q->nr; i++) {
5941                 struct diff_filepair *p = q->queue[i];
5942                 if (check_pair_status(p))
5943                         diff_flush_patch(p, o);
5944         }
5945
5946         if (o->emitted_symbols) {
5947                 if (o->color_moved) {
5948                         struct hashmap add_lines, del_lines;
5949
5950                         if (o->color_moved_ws_handling &
5951                             COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE)
5952                                 o->color_moved_ws_handling |= XDF_IGNORE_WHITESPACE;
5953
5954                         hashmap_init(&del_lines, moved_entry_cmp, o, 0);
5955                         hashmap_init(&add_lines, moved_entry_cmp, o, 0);
5956
5957                         add_lines_to_move_detection(o, &add_lines, &del_lines);
5958                         mark_color_as_moved(o, &add_lines, &del_lines);
5959                         if (o->color_moved == COLOR_MOVED_ZEBRA_DIM)
5960                                 dim_moved_lines(o);
5961
5962                         hashmap_free(&add_lines, 1);
5963                         hashmap_free(&del_lines, 1);
5964                 }
5965
5966                 for (i = 0; i < esm.nr; i++)
5967                         emit_diff_symbol_from_struct(o, &esm.buf[i]);
5968
5969                 for (i = 0; i < esm.nr; i++)
5970                         free((void *)esm.buf[i].line);
5971         }
5972         esm.nr = 0;
5973 }
5974
5975 void diff_flush(struct diff_options *options)
5976 {
5977         struct diff_queue_struct *q = &diff_queued_diff;
5978         int i, output_format = options->output_format;
5979         int separator = 0;
5980         int dirstat_by_line = 0;
5981
5982         /*
5983          * Order: raw, stat, summary, patch
5984          * or:    name/name-status/checkdiff (other bits clear)
5985          */
5986         if (!q->nr)
5987                 goto free_queue;
5988
5989         if (output_format & (DIFF_FORMAT_RAW |
5990                              DIFF_FORMAT_NAME |
5991                              DIFF_FORMAT_NAME_STATUS |
5992                              DIFF_FORMAT_CHECKDIFF)) {
5993                 for (i = 0; i < q->nr; i++) {
5994                         struct diff_filepair *p = q->queue[i];
5995                         if (check_pair_status(p))
5996                                 flush_one_pair(p, options);
5997                 }
5998                 separator++;
5999         }
6000
6001         if (output_format & DIFF_FORMAT_DIRSTAT && options->flags.dirstat_by_line)
6002                 dirstat_by_line = 1;
6003
6004         if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
6005             dirstat_by_line) {
6006                 struct diffstat_t diffstat;
6007
6008                 memset(&diffstat, 0, sizeof(struct diffstat_t));
6009                 for (i = 0; i < q->nr; i++) {
6010                         struct diff_filepair *p = q->queue[i];
6011                         if (check_pair_status(p))
6012                                 diff_flush_stat(p, options, &diffstat);
6013                 }
6014                 if (output_format & DIFF_FORMAT_NUMSTAT)
6015                         show_numstat(&diffstat, options);
6016                 if (output_format & DIFF_FORMAT_DIFFSTAT)
6017                         show_stats(&diffstat, options);
6018                 if (output_format & DIFF_FORMAT_SHORTSTAT)
6019                         show_shortstats(&diffstat, options);
6020                 if (output_format & DIFF_FORMAT_DIRSTAT && dirstat_by_line)
6021                         show_dirstat_by_line(&diffstat, options);
6022                 free_diffstat_info(&diffstat);
6023                 separator++;
6024         }
6025         if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
6026                 show_dirstat(options);
6027
6028         if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
6029                 for (i = 0; i < q->nr; i++) {
6030                         diff_summary(options, q->queue[i]);
6031                 }
6032                 separator++;
6033         }
6034
6035         if (output_format & DIFF_FORMAT_NO_OUTPUT &&
6036             options->flags.exit_with_status &&
6037             options->flags.diff_from_contents) {
6038                 /*
6039                  * run diff_flush_patch for the exit status. setting
6040                  * options->file to /dev/null should be safe, because we
6041                  * aren't supposed to produce any output anyway.
6042                  */
6043                 if (options->close_file)
6044                         fclose(options->file);
6045                 options->file = xfopen("/dev/null", "w");
6046                 options->close_file = 1;
6047                 options->color_moved = 0;
6048                 for (i = 0; i < q->nr; i++) {
6049                         struct diff_filepair *p = q->queue[i];
6050                         if (check_pair_status(p))
6051                                 diff_flush_patch(p, options);
6052                         if (options->found_changes)
6053                                 break;
6054                 }
6055         }
6056
6057         if (output_format & DIFF_FORMAT_PATCH) {
6058                 if (separator) {
6059                         emit_diff_symbol(options, DIFF_SYMBOL_SEPARATOR, NULL, 0, 0);
6060                         if (options->stat_sep)
6061                                 /* attach patch instead of inline */
6062                                 emit_diff_symbol(options, DIFF_SYMBOL_STAT_SEP,
6063                                                  NULL, 0, 0);
6064                 }
6065
6066                 diff_flush_patch_all_file_pairs(options);
6067         }
6068
6069         if (output_format & DIFF_FORMAT_CALLBACK)
6070                 options->format_callback(q, options, options->format_callback_data);
6071
6072         for (i = 0; i < q->nr; i++)
6073                 diff_free_filepair(q->queue[i]);
6074 free_queue:
6075         free(q->queue);
6076         DIFF_QUEUE_CLEAR(q);
6077         if (options->close_file)
6078                 fclose(options->file);
6079
6080         /*
6081          * Report the content-level differences with HAS_CHANGES;
6082          * diff_addremove/diff_change does not set the bit when
6083          * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
6084          */
6085         if (options->flags.diff_from_contents) {
6086                 if (options->found_changes)
6087                         options->flags.has_changes = 1;
6088                 else
6089                         options->flags.has_changes = 0;
6090         }
6091 }
6092
6093 static int match_filter(const struct diff_options *options, const struct diff_filepair *p)
6094 {
6095         return (((p->status == DIFF_STATUS_MODIFIED) &&
6096                  ((p->score &&
6097                    filter_bit_tst(DIFF_STATUS_FILTER_BROKEN, options)) ||
6098                   (!p->score &&
6099                    filter_bit_tst(DIFF_STATUS_MODIFIED, options)))) ||
6100                 ((p->status != DIFF_STATUS_MODIFIED) &&
6101                  filter_bit_tst(p->status, options)));
6102 }
6103
6104 static void diffcore_apply_filter(struct diff_options *options)
6105 {
6106         int i;
6107         struct diff_queue_struct *q = &diff_queued_diff;
6108         struct diff_queue_struct outq;
6109
6110         DIFF_QUEUE_CLEAR(&outq);
6111
6112         if (!options->filter)
6113                 return;
6114
6115         if (filter_bit_tst(DIFF_STATUS_FILTER_AON, options)) {
6116                 int found;
6117                 for (i = found = 0; !found && i < q->nr; i++) {
6118                         if (match_filter(options, q->queue[i]))
6119                                 found++;
6120                 }
6121                 if (found)
6122                         return;
6123
6124                 /* otherwise we will clear the whole queue
6125                  * by copying the empty outq at the end of this
6126                  * function, but first clear the current entries
6127                  * in the queue.
6128                  */
6129                 for (i = 0; i < q->nr; i++)
6130                         diff_free_filepair(q->queue[i]);
6131         }
6132         else {
6133                 /* Only the matching ones */
6134                 for (i = 0; i < q->nr; i++) {
6135                         struct diff_filepair *p = q->queue[i];
6136                         if (match_filter(options, p))
6137                                 diff_q(&outq, p);
6138                         else
6139                                 diff_free_filepair(p);
6140                 }
6141         }
6142         free(q->queue);
6143         *q = outq;
6144 }
6145
6146 /* Check whether two filespecs with the same mode and size are identical */
6147 static int diff_filespec_is_identical(struct repository *r,
6148                                       struct diff_filespec *one,
6149                                       struct diff_filespec *two)
6150 {
6151         if (S_ISGITLINK(one->mode))
6152                 return 0;
6153         if (diff_populate_filespec(r, one, 0))
6154                 return 0;
6155         if (diff_populate_filespec(r, two, 0))
6156                 return 0;
6157         return !memcmp(one->data, two->data, one->size);
6158 }
6159
6160 static int diff_filespec_check_stat_unmatch(struct repository *r,
6161                                             struct diff_filepair *p)
6162 {
6163         if (p->done_skip_stat_unmatch)
6164                 return p->skip_stat_unmatch_result;
6165
6166         p->done_skip_stat_unmatch = 1;
6167         p->skip_stat_unmatch_result = 0;
6168         /*
6169          * 1. Entries that come from stat info dirtiness
6170          *    always have both sides (iow, not create/delete),
6171          *    one side of the object name is unknown, with
6172          *    the same mode and size.  Keep the ones that
6173          *    do not match these criteria.  They have real
6174          *    differences.
6175          *
6176          * 2. At this point, the file is known to be modified,
6177          *    with the same mode and size, and the object
6178          *    name of one side is unknown.  Need to inspect
6179          *    the identical contents.
6180          */
6181         if (!DIFF_FILE_VALID(p->one) || /* (1) */
6182             !DIFF_FILE_VALID(p->two) ||
6183             (p->one->oid_valid && p->two->oid_valid) ||
6184             (p->one->mode != p->two->mode) ||
6185             diff_populate_filespec(r, p->one, CHECK_SIZE_ONLY) ||
6186             diff_populate_filespec(r, p->two, CHECK_SIZE_ONLY) ||
6187             (p->one->size != p->two->size) ||
6188             !diff_filespec_is_identical(r, p->one, p->two)) /* (2) */
6189                 p->skip_stat_unmatch_result = 1;
6190         return p->skip_stat_unmatch_result;
6191 }
6192
6193 static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
6194 {
6195         int i;
6196         struct diff_queue_struct *q = &diff_queued_diff;
6197         struct diff_queue_struct outq;
6198         DIFF_QUEUE_CLEAR(&outq);
6199
6200         for (i = 0; i < q->nr; i++) {
6201                 struct diff_filepair *p = q->queue[i];
6202
6203                 if (diff_filespec_check_stat_unmatch(diffopt->repo, p))
6204                         diff_q(&outq, p);
6205                 else {
6206                         /*
6207                          * The caller can subtract 1 from skip_stat_unmatch
6208                          * to determine how many paths were dirty only
6209                          * due to stat info mismatch.
6210                          */
6211                         if (!diffopt->flags.no_index)
6212                                 diffopt->skip_stat_unmatch++;
6213                         diff_free_filepair(p);
6214                 }
6215         }
6216         free(q->queue);
6217         *q = outq;
6218 }
6219
6220 static int diffnamecmp(const void *a_, const void *b_)
6221 {
6222         const struct diff_filepair *a = *((const struct diff_filepair **)a_);
6223         const struct diff_filepair *b = *((const struct diff_filepair **)b_);
6224         const char *name_a, *name_b;
6225
6226         name_a = a->one ? a->one->path : a->two->path;
6227         name_b = b->one ? b->one->path : b->two->path;
6228         return strcmp(name_a, name_b);
6229 }
6230
6231 void diffcore_fix_diff_index(struct diff_options *options)
6232 {
6233         struct diff_queue_struct *q = &diff_queued_diff;
6234         QSORT(q->queue, q->nr, diffnamecmp);
6235 }
6236
6237 void diffcore_std(struct diff_options *options)
6238 {
6239         /* NOTE please keep the following in sync with diff_tree_combined() */
6240         if (options->skip_stat_unmatch)
6241                 diffcore_skip_stat_unmatch(options);
6242         if (!options->found_follow) {
6243                 /* See try_to_follow_renames() in tree-diff.c */
6244                 if (options->break_opt != -1)
6245                         diffcore_break(options->repo,
6246                                        options->break_opt);
6247                 if (options->detect_rename)
6248                         diffcore_rename(options);
6249                 if (options->break_opt != -1)
6250                         diffcore_merge_broken();
6251         }
6252         if (options->pickaxe_opts & DIFF_PICKAXE_KINDS_MASK)
6253                 diffcore_pickaxe(options);
6254         if (options->orderfile)
6255                 diffcore_order(options->orderfile);
6256         if (!options->found_follow)
6257                 /* See try_to_follow_renames() in tree-diff.c */
6258                 diff_resolve_rename_copy();
6259         diffcore_apply_filter(options);
6260
6261         if (diff_queued_diff.nr && !options->flags.diff_from_contents)
6262                 options->flags.has_changes = 1;
6263         else
6264                 options->flags.has_changes = 0;
6265
6266         options->found_follow = 0;
6267 }
6268
6269 int diff_result_code(struct diff_options *opt, int status)
6270 {
6271         int result = 0;
6272
6273         diff_warn_rename_limit("diff.renameLimit",
6274                                opt->needed_rename_limit,
6275                                opt->degraded_cc_to_c);
6276         if (!opt->flags.exit_with_status &&
6277             !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
6278                 return status;
6279         if (opt->flags.exit_with_status &&
6280             opt->flags.has_changes)
6281                 result |= 01;
6282         if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
6283             opt->flags.check_failed)
6284                 result |= 02;
6285         return result;
6286 }
6287
6288 int diff_can_quit_early(struct diff_options *opt)
6289 {
6290         return (opt->flags.quick &&
6291                 !opt->filter &&
6292                 opt->flags.has_changes);
6293 }
6294
6295 /*
6296  * Shall changes to this submodule be ignored?
6297  *
6298  * Submodule changes can be configured to be ignored separately for each path,
6299  * but that configuration can be overridden from the command line.
6300  */
6301 static int is_submodule_ignored(const char *path, struct diff_options *options)
6302 {
6303         int ignored = 0;
6304         struct diff_flags orig_flags = options->flags;
6305         if (!options->flags.override_submodule_config)
6306                 set_diffopt_flags_from_submodule_config(options, path);
6307         if (options->flags.ignore_submodules)
6308                 ignored = 1;
6309         options->flags = orig_flags;
6310         return ignored;
6311 }
6312
6313 void diff_addremove(struct diff_options *options,
6314                     int addremove, unsigned mode,
6315                     const struct object_id *oid,
6316                     int oid_valid,
6317                     const char *concatpath, unsigned dirty_submodule)
6318 {
6319         struct diff_filespec *one, *two;
6320
6321         if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
6322                 return;
6323
6324         /* This may look odd, but it is a preparation for
6325          * feeding "there are unchanged files which should
6326          * not produce diffs, but when you are doing copy
6327          * detection you would need them, so here they are"
6328          * entries to the diff-core.  They will be prefixed
6329          * with something like '=' or '*' (I haven't decided
6330          * which but should not make any difference).
6331          * Feeding the same new and old to diff_change()
6332          * also has the same effect.
6333          * Before the final output happens, they are pruned after
6334          * merged into rename/copy pairs as appropriate.
6335          */
6336         if (options->flags.reverse_diff)
6337                 addremove = (addremove == '+' ? '-' :
6338                              addremove == '-' ? '+' : addremove);
6339
6340         if (options->prefix &&
6341             strncmp(concatpath, options->prefix, options->prefix_length))
6342                 return;
6343
6344         one = alloc_filespec(concatpath);
6345         two = alloc_filespec(concatpath);
6346
6347         if (addremove != '+')
6348                 fill_filespec(one, oid, oid_valid, mode);
6349         if (addremove != '-') {
6350                 fill_filespec(two, oid, oid_valid, mode);
6351                 two->dirty_submodule = dirty_submodule;
6352         }
6353
6354         diff_queue(&diff_queued_diff, one, two);
6355         if (!options->flags.diff_from_contents)
6356                 options->flags.has_changes = 1;
6357 }
6358
6359 void diff_change(struct diff_options *options,
6360                  unsigned old_mode, unsigned new_mode,
6361                  const struct object_id *old_oid,
6362                  const struct object_id *new_oid,
6363                  int old_oid_valid, int new_oid_valid,
6364                  const char *concatpath,
6365                  unsigned old_dirty_submodule, unsigned new_dirty_submodule)
6366 {
6367         struct diff_filespec *one, *two;
6368         struct diff_filepair *p;
6369
6370         if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
6371             is_submodule_ignored(concatpath, options))
6372                 return;
6373
6374         if (options->flags.reverse_diff) {
6375                 SWAP(old_mode, new_mode);
6376                 SWAP(old_oid, new_oid);
6377                 SWAP(old_oid_valid, new_oid_valid);
6378                 SWAP(old_dirty_submodule, new_dirty_submodule);
6379         }
6380
6381         if (options->prefix &&
6382             strncmp(concatpath, options->prefix, options->prefix_length))
6383                 return;
6384
6385         one = alloc_filespec(concatpath);
6386         two = alloc_filespec(concatpath);
6387         fill_filespec(one, old_oid, old_oid_valid, old_mode);
6388         fill_filespec(two, new_oid, new_oid_valid, new_mode);
6389         one->dirty_submodule = old_dirty_submodule;
6390         two->dirty_submodule = new_dirty_submodule;
6391         p = diff_queue(&diff_queued_diff, one, two);
6392
6393         if (options->flags.diff_from_contents)
6394                 return;
6395
6396         if (options->flags.quick && options->skip_stat_unmatch &&
6397             !diff_filespec_check_stat_unmatch(options->repo, p))
6398                 return;
6399
6400         options->flags.has_changes = 1;
6401 }
6402
6403 struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
6404 {
6405         struct diff_filepair *pair;
6406         struct diff_filespec *one, *two;
6407
6408         if (options->prefix &&
6409             strncmp(path, options->prefix, options->prefix_length))
6410                 return NULL;
6411
6412         one = alloc_filespec(path);
6413         two = alloc_filespec(path);
6414         pair = diff_queue(&diff_queued_diff, one, two);
6415         pair->is_unmerged = 1;
6416         return pair;
6417 }
6418
6419 static char *run_textconv(struct repository *r,
6420                           const char *pgm,
6421                           struct diff_filespec *spec,
6422                           size_t *outsize)
6423 {
6424         struct diff_tempfile *temp;
6425         const char *argv[3];
6426         const char **arg = argv;
6427         struct child_process child = CHILD_PROCESS_INIT;
6428         struct strbuf buf = STRBUF_INIT;
6429         int err = 0;
6430
6431         temp = prepare_temp_file(r, spec->path, spec);
6432         *arg++ = pgm;
6433         *arg++ = temp->name;
6434         *arg = NULL;
6435
6436         child.use_shell = 1;
6437         child.argv = argv;
6438         child.out = -1;
6439         if (start_command(&child)) {
6440                 remove_tempfile();
6441                 return NULL;
6442         }
6443
6444         if (strbuf_read(&buf, child.out, 0) < 0)
6445                 err = error("error reading from textconv command '%s'", pgm);
6446         close(child.out);
6447
6448         if (finish_command(&child) || err) {
6449                 strbuf_release(&buf);
6450                 remove_tempfile();
6451                 return NULL;
6452         }
6453         remove_tempfile();
6454
6455         return strbuf_detach(&buf, outsize);
6456 }
6457
6458 size_t fill_textconv(struct repository *r,
6459                      struct userdiff_driver *driver,
6460                      struct diff_filespec *df,
6461                      char **outbuf)
6462 {
6463         size_t size;
6464
6465         if (!driver) {
6466                 if (!DIFF_FILE_VALID(df)) {
6467                         *outbuf = "";
6468                         return 0;
6469                 }
6470                 if (diff_populate_filespec(r, df, 0))
6471                         die("unable to read files to diff");
6472                 *outbuf = df->data;
6473                 return df->size;
6474         }
6475
6476         if (!driver->textconv)
6477                 BUG("fill_textconv called with non-textconv driver");
6478
6479         if (driver->textconv_cache && df->oid_valid) {
6480                 *outbuf = notes_cache_get(driver->textconv_cache,
6481                                           &df->oid,
6482                                           &size);
6483                 if (*outbuf)
6484                         return size;
6485         }
6486
6487         *outbuf = run_textconv(r, driver->textconv, df, &size);
6488         if (!*outbuf)
6489                 die("unable to read files to diff");
6490
6491         if (driver->textconv_cache && df->oid_valid) {
6492                 /* ignore errors, as we might be in a readonly repository */
6493                 notes_cache_put(driver->textconv_cache, &df->oid, *outbuf,
6494                                 size);
6495                 /*
6496                  * we could save up changes and flush them all at the end,
6497                  * but we would need an extra call after all diffing is done.
6498                  * Since generating a cache entry is the slow path anyway,
6499                  * this extra overhead probably isn't a big deal.
6500                  */
6501                 notes_cache_write(driver->textconv_cache);
6502         }
6503
6504         return size;
6505 }
6506
6507 int textconv_object(struct repository *r,
6508                     const char *path,
6509                     unsigned mode,
6510                     const struct object_id *oid,
6511                     int oid_valid,
6512                     char **buf,
6513                     unsigned long *buf_size)
6514 {
6515         struct diff_filespec *df;
6516         struct userdiff_driver *textconv;
6517
6518         df = alloc_filespec(path);
6519         fill_filespec(df, oid, oid_valid, mode);
6520         textconv = get_textconv(r, df);
6521         if (!textconv) {
6522                 free_filespec(df);
6523                 return 0;
6524         }
6525
6526         *buf_size = fill_textconv(r, textconv, df, buf);
6527         free_filespec(df);
6528         return 1;
6529 }
6530
6531 void setup_diff_pager(struct diff_options *opt)
6532 {
6533         /*
6534          * If the user asked for our exit code, then either they want --quiet
6535          * or --exit-code. We should definitely not bother with a pager in the
6536          * former case, as we will generate no output. Since we still properly
6537          * report our exit code even when a pager is run, we _could_ run a
6538          * pager with --exit-code. But since we have not done so historically,
6539          * and because it is easy to find people oneline advising "git diff
6540          * --exit-code" in hooks and other scripts, we do not do so.
6541          */
6542         if (!opt->flags.exit_with_status &&
6543             check_pager_config("diff") != 0)
6544                 setup_pager();
6545 }