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