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