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 "userdiff.h"
  17 #include "submodule-config.h"
  18 #include "submodule.h"
  19 #include "ll-merge.h"
  20 #include "string-list.h"
  21 #include "argv-array.h"
  22 #include "graph.h"
  23
  24 #ifdef NO_FAST_WORKING_DIRECTORY
  25 #define FAST_WORKING_DIRECTORY 0
  26 #else
  27 #define FAST_WORKING_DIRECTORY 1
  28 #endif
  29
  30 static int diff_detect_rename_default;
  31 static int diff_indent_heuristic = 1;
  32 static int diff_rename_limit_default = 400;
  33 static int diff_suppress_blank_empty;
  34 static int diff_use_color_default = -1;
  35 static int diff_context_default = 3;
  36 static int diff_interhunk_context_default;
  37 static const char *diff_word_regex_cfg;
  38 static const char *external_diff_cmd_cfg;
  39 static const char *diff_order_file_cfg;
  40 int diff_auto_refresh_index = 1;
  41 static int diff_mnemonic_prefix;
  42 static int diff_no_prefix;
  43 static int diff_stat_graph_width;
  44 static int diff_dirstat_permille_default = 30;
  45 static struct diff_options default_diff_options;
  46 static long diff_algorithm;
  47 static unsigned ws_error_highlight_default = WSEH_NEW;
  48
  49 static char diff_colors[][COLOR_MAXLEN] = {
  50         GIT_COLOR_RESET,
  51         GIT_COLOR_NORMAL,       /* CONTEXT */
  52         GIT_COLOR_BOLD,         /* METAINFO */
  53         GIT_COLOR_CYAN,         /* FRAGINFO */
  54         GIT_COLOR_RED,          /* OLD */
  55         GIT_COLOR_GREEN,        /* NEW */
  56         GIT_COLOR_YELLOW,       /* COMMIT */
  57         GIT_COLOR_BG_RED,       /* WHITESPACE */
  58         GIT_COLOR_NORMAL,       /* FUNCINFO */
  59 };
  60
  61 static NORETURN void die_want_option(const char *option_name)
  62 {
  63         die(_("option '%s' requires a value"), option_name);
  64 }
  65
  66 static int parse_diff_color_slot(const char *var)
  67 {
  68         if (!strcasecmp(var, "context") || !strcasecmp(var, "plain"))
  69                 return DIFF_CONTEXT;
  70         if (!strcasecmp(var, "meta"))
  71                 return DIFF_METAINFO;
  72         if (!strcasecmp(var, "frag"))
  73                 return DIFF_FRAGINFO;
  74         if (!strcasecmp(var, "old"))
  75                 return DIFF_FILE_OLD;
  76         if (!strcasecmp(var, "new"))
  77                 return DIFF_FILE_NEW;
  78         if (!strcasecmp(var, "commit"))
  79                 return DIFF_COMMIT;
  80         if (!strcasecmp(var, "whitespace"))
  81                 return DIFF_WHITESPACE;
  82         if (!strcasecmp(var, "func"))
  83                 return DIFF_FUNCINFO;
  84         return -1;
  85 }
  86
  87 static int parse_dirstat_params(struct diff_options *options, const char *params_string,
  88                                 struct strbuf *errmsg)
  89 {
  90         char *params_copy = xstrdup(params_string);
  91         struct string_list params = STRING_LIST_INIT_NODUP;
  92         int ret = 0;
  93         int i;
  94
  95         if (*params_copy)
  96                 string_list_split_in_place(&params, params_copy, ',', -1);
  97         for (i = 0; i < params.nr; i++) {
  98                 const char *p = params.items[i].string;
  99                 if (!strcmp(p, "changes")) {
 100                         DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
 101                         DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
 102                 } else if (!strcmp(p, "lines")) {
 103                         DIFF_OPT_SET(options, DIRSTAT_BY_LINE);
 104                         DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
 105                 } else if (!strcmp(p, "files")) {
 106                         DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
 107                         DIFF_OPT_SET(options, DIRSTAT_BY_FILE);
 108                 } else if (!strcmp(p, "noncumulative")) {
 109                         DIFF_OPT_CLR(options, DIRSTAT_CUMULATIVE);
 110                 } else if (!strcmp(p, "cumulative")) {
 111                         DIFF_OPT_SET(options, DIRSTAT_CUMULATIVE);
 112                 } else if (isdigit(*p)) {
 113                         char *end;
 114                         int permille = strtoul(p, &end, 10) * 10;
 115                         if (*end == '.' && isdigit(*++end)) {
 116                                 /* only use first digit */
 117                                 permille += *end - '0';
 118                                 /* .. and ignore any further digits */
 119                                 while (isdigit(*++end))
 120                                         ; /* nothing */
 121                         }
 122                         if (!*end)
 123                                 options->dirstat_permille = permille;
 124                         else {
 125                                 strbuf_addf(errmsg, _("  Failed to parse dirstat cut-off percentage '%s'\n"),
 126                                             p);
 127                                 ret++;
 128                         }
 129                 } else {
 130                         strbuf_addf(errmsg, _("  Unknown dirstat parameter '%s'\n"), p);
 131                         ret++;
 132                 }
 133
 134         }
 135         string_list_clear(&params, 0);
 136         free(params_copy);
 137         return ret;
 138 }
 139
 140 static int parse_submodule_params(struct diff_options *options, const char *value)
 141 {
 142         if (!strcmp(value, "log"))
 143                 options->submodule_format = DIFF_SUBMODULE_LOG;
 144         else if (!strcmp(value, "short"))
 145                 options->submodule_format = DIFF_SUBMODULE_SHORT;
 146         else if (!strcmp(value, "diff"))
 147                 options->submodule_format = DIFF_SUBMODULE_INLINE_DIFF;
 148         else
 149                 return -1;
 150         return 0;
 151 }
 152
 153 static int git_config_rename(const char *var, const char *value)
 154 {
 155         if (!value)
 156                 return DIFF_DETECT_RENAME;
 157         if (!strcasecmp(value, "copies") || !strcasecmp(value, "copy"))
 158                 return  DIFF_DETECT_COPY;
 159         return git_config_bool(var,value) ? DIFF_DETECT_RENAME : 0;
 160 }
 161
 162 long parse_algorithm_value(const char *value)
 163 {
 164         if (!value)
 165                 return -1;
 166         else if (!strcasecmp(value, "myers") || !strcasecmp(value, "default"))
 167                 return 0;
 168         else if (!strcasecmp(value, "minimal"))
 169                 return XDF_NEED_MINIMAL;
 170         else if (!strcasecmp(value, "patience"))
 171                 return XDF_PATIENCE_DIFF;
 172         else if (!strcasecmp(value, "histogram"))
 173                 return XDF_HISTOGRAM_DIFF;
 174         return -1;
 175 }
 176
 177 static int parse_one_token(const char **arg, const char *token)
 178 {
 179         const char *rest;
 180         if (skip_prefix(*arg, token, &rest) && (!*rest || *rest == ',')) {
 181                 *arg = rest;
 182                 return 1;
 183         }
 184         return 0;
 185 }
 186
 187 static int parse_ws_error_highlight(const char *arg)
 188 {
 189         const char *orig_arg = arg;
 190         unsigned val = 0;
 191
 192         while (*arg) {
 193                 if (parse_one_token(&arg, "none"))
 194                         val = 0;
 195                 else if (parse_one_token(&arg, "default"))
 196                         val = WSEH_NEW;
 197                 else if (parse_one_token(&arg, "all"))
 198                         val = WSEH_NEW | WSEH_OLD | WSEH_CONTEXT;
 199                 else if (parse_one_token(&arg, "new"))
 200                         val |= WSEH_NEW;
 201                 else if (parse_one_token(&arg, "old"))
 202                         val |= WSEH_OLD;
 203                 else if (parse_one_token(&arg, "context"))
 204                         val |= WSEH_CONTEXT;
 205                 else {
 206                         return -1 - (int)(arg - orig_arg);
 207                 }
 208                 if (*arg)
 209                         arg++;
 210         }
 211         return val;
 212 }
 213
 214 /*
 215  * These are to give UI layer defaults.
 216  * The core-level commands such as git-diff-files should
 217  * never be affected by the setting of diff.renames
 218  * the user happens to have in the configuration file.
 219  */
 220 void init_diff_ui_defaults(void)
 221 {
 222         diff_detect_rename_default = 1;
 223 }
 224
 225 int git_diff_heuristic_config(const char *var, const char *value, void *cb)
 226 {
 227         if (!strcmp(var, "diff.indentheuristic"))
 228                 diff_indent_heuristic = git_config_bool(var, value);
 229         return 0;
 230 }
 231
 232 int git_diff_ui_config(const char *var, const char *value, void *cb)
 233 {
 234         if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 235                 diff_use_color_default = git_config_colorbool(var, value);
 236                 return 0;
 237         }
 238         if (!strcmp(var, "diff.context")) {
 239                 diff_context_default = git_config_int(var, value);
 240                 if (diff_context_default < 0)
 241                         return -1;
 242                 return 0;
 243         }
 244         if (!strcmp(var, "diff.interhunkcontext")) {
 245                 diff_interhunk_context_default = git_config_int(var, value);
 246                 if (diff_interhunk_context_default < 0)
 247                         return -1;
 248                 return 0;
 249         }
 250         if (!strcmp(var, "diff.renames")) {
 251                 diff_detect_rename_default = git_config_rename(var, value);
 252                 return 0;
 253         }
 254         if (!strcmp(var, "diff.autorefreshindex")) {
 255                 diff_auto_refresh_index = git_config_bool(var, value);
 256                 return 0;
 257         }
 258         if (!strcmp(var, "diff.mnemonicprefix")) {
 259                 diff_mnemonic_prefix = git_config_bool(var, value);
 260                 return 0;
 261         }
 262         if (!strcmp(var, "diff.noprefix")) {
 263                 diff_no_prefix = git_config_bool(var, value);
 264                 return 0;
 265         }
 266         if (!strcmp(var, "diff.statgraphwidth")) {
 267                 diff_stat_graph_width = git_config_int(var, value);
 268                 return 0;
 269         }
 270         if (!strcmp(var, "diff.external"))
 271                 return git_config_string(&external_diff_cmd_cfg, var, value);
 272         if (!strcmp(var, "diff.wordregex"))
 273                 return git_config_string(&diff_word_regex_cfg, var, value);
 274         if (!strcmp(var, "diff.orderfile"))
 275                 return git_config_pathname(&diff_order_file_cfg, var, value);
 276
 277         if (!strcmp(var, "diff.ignoresubmodules"))
 278                 handle_ignore_submodules_arg(&default_diff_options, value);
 279
 280         if (!strcmp(var, "diff.submodule")) {
 281                 if (parse_submodule_params(&default_diff_options, value))
 282                         warning(_("Unknown value for 'diff.submodule' config variable: '%s'"),
 283                                 value);
 284                 return 0;
 285         }
 286
 287         if (!strcmp(var, "diff.algorithm")) {
 288                 diff_algorithm = parse_algorithm_value(value);
 289                 if (diff_algorithm < 0)
 290                         return -1;
 291                 return 0;
 292         }
 293
 294         if (!strcmp(var, "diff.wserrorhighlight")) {
 295                 int val = parse_ws_error_highlight(value);
 296                 if (val < 0)
 297                         return -1;
 298                 ws_error_highlight_default = val;
 299                 return 0;
 300         }
 301
 302         return git_diff_basic_config(var, value, cb);
 303 }
 304
 305 int git_diff_basic_config(const char *var, const char *value, void *cb)
 306 {
 307         const char *name;
 308
 309         if (!strcmp(var, "diff.renamelimit")) {
 310                 diff_rename_limit_default = git_config_int(var, value);
 311                 return 0;
 312         }
 313
 314         if (userdiff_config(var, value) < 0)
 315                 return -1;
 316
 317         if (skip_prefix(var, "diff.color.", &name) ||
 318             skip_prefix(var, "color.diff.", &name)) {
 319                 int slot = parse_diff_color_slot(name);
 320                 if (slot < 0)
 321                         return 0;
 322                 if (!value)
 323                         return config_error_nonbool(var);
 324                 return color_parse(value, diff_colors[slot]);
 325         }
 326
 327         /* like GNU diff's --suppress-blank-empty option  */
 328         if (!strcmp(var, "diff.suppressblankempty") ||
 329                         /* for backwards compatibility */
 330                         !strcmp(var, "diff.suppress-blank-empty")) {
 331                 diff_suppress_blank_empty = git_config_bool(var, value);
 332                 return 0;
 333         }
 334
 335         if (!strcmp(var, "diff.dirstat")) {
 336                 struct strbuf errmsg = STRBUF_INIT;
 337                 default_diff_options.dirstat_permille = diff_dirstat_permille_default;
 338                 if (parse_dirstat_params(&default_diff_options, value, &errmsg))
 339                         warning(_("Found errors in 'diff.dirstat' config variable:\n%s"),
 340                                 errmsg.buf);
 341                 strbuf_release(&errmsg);
 342                 diff_dirstat_permille_default = default_diff_options.dirstat_permille;
 343                 return 0;
 344         }
 345
 346         if (starts_with(var, "submodule."))
 347                 return parse_submodule_config_option(var, value);
 348
 349         if (git_diff_heuristic_config(var, value, cb) < 0)
 350                 return -1;
 351
 352         return git_default_config(var, value, cb);
 353 }
 354
 355 static char *quote_two(const char *one, const char *two)
 356 {
 357         int need_one = quote_c_style(one, NULL, NULL, 1);
 358         int need_two = quote_c_style(two, NULL, NULL, 1);
 359         struct strbuf res = STRBUF_INIT;
 360
 361         if (need_one + need_two) {
 362                 strbuf_addch(&res, '"');
 363                 quote_c_style(one, &res, NULL, 1);
 364                 quote_c_style(two, &res, NULL, 1);
 365                 strbuf_addch(&res, '"');
 366         } else {
 367                 strbuf_addstr(&res, one);
 368                 strbuf_addstr(&res, two);
 369         }
 370         return strbuf_detach(&res, NULL);
 371 }
 372
 373 static const char *external_diff(void)
 374 {
 375         static const char *external_diff_cmd = NULL;
 376         static int done_preparing = 0;
 377
 378         if (done_preparing)
 379                 return external_diff_cmd;
 380         external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 381         if (!external_diff_cmd)
 382                 external_diff_cmd = external_diff_cmd_cfg;
 383         done_preparing = 1;
 384         return external_diff_cmd;
 385 }
 386
 387 /*
 388  * Keep track of files used for diffing. Sometimes such an entry
 389  * refers to a temporary file, sometimes to an existing file, and
 390  * sometimes to "/dev/null".
 391  */
 392 static struct diff_tempfile {
 393         /*
 394          * filename external diff should read from, or NULL if this
 395          * entry is currently not in use:
 396          */
 397         const char *name;
 398
 399         char hex[GIT_MAX_HEXSZ + 1];
 400         char mode[10];
 401
 402         /*
 403          * If this diff_tempfile instance refers to a temporary file,
 404          * this tempfile object is used to manage its lifetime.
 405          */
 406         struct tempfile tempfile;
 407 } diff_temp[2];
 408
 409 typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
 410
 411 struct emit_callback {
 412         int color_diff;
 413         unsigned ws_rule;
 414         int blank_at_eof_in_preimage;
 415         int blank_at_eof_in_postimage;
 416         int lno_in_preimage;
 417         int lno_in_postimage;
 418         sane_truncate_fn truncate;
 419         const char **label_path;
 420         struct diff_words_data *diff_words;
 421         struct diff_options *opt;
 422         struct strbuf *header;
 423 };
 424
 425 static int count_lines(const char *data, int size)
 426 {
 427         int count, ch, completely_empty = 1, nl_just_seen = 0;
 428         count = 0;
 429         while (0 < size--) {
 430                 ch = *data++;
 431                 if (ch == '\n') {
 432                         count++;
 433                         nl_just_seen = 1;
 434                         completely_empty = 0;
 435                 }
 436                 else {
 437                         nl_just_seen = 0;
 438                         completely_empty = 0;
 439                 }
 440         }
 441         if (completely_empty)
 442                 return 0;
 443         if (!nl_just_seen)
 444                 count++; /* no trailing newline */
 445         return count;
 446 }
 447
 448 static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 449 {
 450         if (!DIFF_FILE_VALID(one)) {
 451                 mf->ptr = (char *)""; /* does not matter */
 452                 mf->size = 0;
 453                 return 0;
 454         }
 455         else if (diff_populate_filespec(one, 0))
 456                 return -1;
 457
 458         mf->ptr = one->data;
 459         mf->size = one->size;
 460         return 0;
 461 }
 462
 463 /* like fill_mmfile, but only for size, so we can avoid retrieving blob */
 464 static unsigned long diff_filespec_size(struct diff_filespec *one)
 465 {
 466         if (!DIFF_FILE_VALID(one))
 467                 return 0;
 468         diff_populate_filespec(one, CHECK_SIZE_ONLY);
 469         return one->size;
 470 }
 471
 472 static int count_trailing_blank(mmfile_t *mf, unsigned ws_rule)
 473 {
 474         char *ptr = mf->ptr;
 475         long size = mf->size;
 476         int cnt = 0;
 477
 478         if (!size)
 479                 return cnt;
 480         ptr += size - 1; /* pointing at the very end */
 481         if (*ptr != '\n')
 482                 ; /* incomplete line */
 483         else
 484                 ptr--; /* skip the last LF */
 485         while (mf->ptr < ptr) {
 486                 char *prev_eol;
 487                 for (prev_eol = ptr; mf->ptr <= prev_eol; prev_eol--)
 488                         if (*prev_eol == '\n')
 489                                 break;
 490                 if (!ws_blank_line(prev_eol + 1, ptr - prev_eol, ws_rule))
 491                         break;
 492                 cnt++;
 493                 ptr = prev_eol - 1;
 494         }
 495         return cnt;
 496 }
 497
 498 static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
 499                                struct emit_callback *ecbdata)
 500 {
 501         int l1, l2, at;
 502         unsigned ws_rule = ecbdata->ws_rule;
 503         l1 = count_trailing_blank(mf1, ws_rule);
 504         l2 = count_trailing_blank(mf2, ws_rule);
 505         if (l2 <= l1) {
 506                 ecbdata->blank_at_eof_in_preimage = 0;
 507                 ecbdata->blank_at_eof_in_postimage = 0;
 508                 return;
 509         }
 510         at = count_lines(mf1->ptr, mf1->size);
 511         ecbdata->blank_at_eof_in_preimage = (at - l1) + 1;
 512
 513         at = count_lines(mf2->ptr, mf2->size);
 514         ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
 515 }
 516
 517 static void emit_line_0(struct diff_options *o, const char *set, const char *reset,
 518                         int first, const char *line, int len)
 519 {
 520         int has_trailing_newline, has_trailing_carriage_return;
 521         int nofirst;
 522         FILE *file = o->file;
 523
 524         fputs(diff_line_prefix(o), file);
 525
 526         if (len == 0) {
 527                 has_trailing_newline = (first == '\n');
 528                 has_trailing_carriage_return = (!has_trailing_newline &&
 529                                                 (first == '\r'));
 530                 nofirst = has_trailing_newline || has_trailing_carriage_return;
 531         } else {
 532                 has_trailing_newline = (len > 0 && line[len-1] == '\n');
 533                 if (has_trailing_newline)
 534                         len--;
 535                 has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
 536                 if (has_trailing_carriage_return)
 537                         len--;
 538                 nofirst = 0;
 539         }
 540
 541         if (len || !nofirst) {
 542                 fputs(set, file);
 543                 if (!nofirst)
 544                         fputc(first, file);
 545                 fwrite(line, len, 1, file);
 546                 fputs(reset, file);
 547         }
 548         if (has_trailing_carriage_return)
 549                 fputc('\r', file);
 550         if (has_trailing_newline)
 551                 fputc('\n', file);
 552 }
 553
 554 static void emit_line(struct diff_options *o, const char *set, const char *reset,
 555                       const char *line, int len)
 556 {
 557         emit_line_0(o, set, reset, line[0], line+1, len-1);
 558 }
 559
 560 static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
 561 {
 562         if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
 563               ecbdata->blank_at_eof_in_preimage &&
 564               ecbdata->blank_at_eof_in_postimage &&
 565               ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
 566               ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
 567                 return 0;
 568         return ws_blank_line(line, len, ecbdata->ws_rule);
 569 }
 570
 571 static void emit_line_checked(const char *reset,
 572                               struct emit_callback *ecbdata,
 573                               const char *line, int len,
 574                               enum color_diff color,
 575                               unsigned ws_error_highlight,
 576                               char sign)
 577 {
 578         const char *set = diff_get_color(ecbdata->color_diff, color);
 579         const char *ws = NULL;
 580
 581         if (ecbdata->opt->ws_error_highlight & ws_error_highlight) {
 582                 ws = diff_get_color(ecbdata->color_diff, DIFF_WHITESPACE);
 583                 if (!*ws)
 584                         ws = NULL;
 585         }
 586
 587         if (!ws)
 588                 emit_line_0(ecbdata->opt, set, reset, sign, line, len);
 589         else if (sign == '+' && new_blank_line_at_eof(ecbdata, line, len))
 590                 /* Blank line at EOF - paint '+' as well */
 591                 emit_line_0(ecbdata->opt, ws, reset, sign, line, len);
 592         else {
 593                 /* Emit just the prefix, then the rest. */
 594                 emit_line_0(ecbdata->opt, set, reset, sign, "", 0);
 595                 ws_check_emit(line, len, ecbdata->ws_rule,
 596                               ecbdata->opt->file, set, reset, ws);
 597         }
 598 }
 599
 600 static void emit_add_line(const char *reset,
 601                           struct emit_callback *ecbdata,
 602                           const char *line, int len)
 603 {
 604         emit_line_checked(reset, ecbdata, line, len,
 605                           DIFF_FILE_NEW, WSEH_NEW, '+');
 606 }
 607
 608 static void emit_del_line(const char *reset,
 609                           struct emit_callback *ecbdata,
 610                           const char *line, int len)
 611 {
 612         emit_line_checked(reset, ecbdata, line, len,
 613                           DIFF_FILE_OLD, WSEH_OLD, '-');
 614 }
 615
 616 static void emit_context_line(const char *reset,
 617                               struct emit_callback *ecbdata,
 618                               const char *line, int len)
 619 {
 620         emit_line_checked(reset, ecbdata, line, len,
 621                           DIFF_CONTEXT, WSEH_CONTEXT, ' ');
 622 }
 623
 624 static void emit_hunk_header(struct emit_callback *ecbdata,
 625                              const char *line, int len)
 626 {
 627         const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
 628         const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
 629         const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
 630         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
 631         static const char atat[2] = { '@', '@' };
 632         const char *cp, *ep;
 633         struct strbuf msgbuf = STRBUF_INIT;
 634         int org_len = len;
 635         int i = 1;
 636
 637         /*
 638          * As a hunk header must begin with "@@ -<old>, +<new> @@",
 639          * it always is at least 10 bytes long.
 640          */
 641         if (len < 10 ||
 642             memcmp(line, atat, 2) ||
 643             !(ep = memmem(line + 2, len - 2, atat, 2))) {
 644                 emit_line(ecbdata->opt, context, reset, line, len);
 645                 return;
 646         }
 647         ep += 2; /* skip over @@ */
 648
 649         /* The hunk header in fraginfo color */
 650         strbuf_addstr(&msgbuf, frag);
 651         strbuf_add(&msgbuf, line, ep - line);
 652         strbuf_addstr(&msgbuf, reset);
 653
 654         /*
 655          * trailing "\r\n"
 656          */
 657         for ( ; i < 3; i++)
 658                 if (line[len - i] == '\r' || line[len - i] == '\n')
 659                         len--;
 660
 661         /* blank before the func header */
 662         for (cp = ep; ep - line < len; ep++)
 663                 if (*ep != ' ' && *ep != '\t')
 664                         break;
 665         if (ep != cp) {
 666                 strbuf_addstr(&msgbuf, context);
 667                 strbuf_add(&msgbuf, cp, ep - cp);
 668                 strbuf_addstr(&msgbuf, reset);
 669         }
 670
 671         if (ep < line + len) {
 672                 strbuf_addstr(&msgbuf, func);
 673                 strbuf_add(&msgbuf, ep, line + len - ep);
 674                 strbuf_addstr(&msgbuf, reset);
 675         }
 676
 677         strbuf_add(&msgbuf, line + len, org_len - len);
 678         emit_line(ecbdata->opt, "", "", msgbuf.buf, msgbuf.len);
 679         strbuf_release(&msgbuf);
 680 }
 681
 682 static struct diff_tempfile *claim_diff_tempfile(void) {
 683         int i;
 684         for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
 685                 if (!diff_temp[i].name)
 686                         return diff_temp + i;
 687         die("BUG: diff is failing to clean up its tempfiles");
 688 }
 689
 690 static void remove_tempfile(void)
 691 {
 692         int i;
 693         for (i = 0; i < ARRAY_SIZE(diff_temp); i++) {
 694                 if (is_tempfile_active(&diff_temp[i].tempfile))
 695                         delete_tempfile(&diff_temp[i].tempfile);
 696                 diff_temp[i].name = NULL;
 697         }
 698 }
 699
 700 static void print_line_count(FILE *file, int count)
 701 {
 702         switch (count) {
 703         case 0:
 704                 fprintf(file, "0,0");
 705                 break;
 706         case 1:
 707                 fprintf(file, "1");
 708                 break;
 709         default:
 710                 fprintf(file, "1,%d", count);
 711                 break;
 712         }
 713 }
 714
 715 static void emit_rewrite_lines(struct emit_callback *ecb,
 716                                int prefix, const char *data, int size)
 717 {
 718         const char *endp = NULL;
 719         static const char *nneof = " No newline at end of file\n";
 720         const char *reset = diff_get_color(ecb->color_diff, DIFF_RESET);
 721
 722         while (0 < size) {
 723                 int len;
 724
 725                 endp = memchr(data, '\n', size);
 726                 len = endp ? (endp - data + 1) : size;
 727                 if (prefix != '+') {
 728                         ecb->lno_in_preimage++;
 729                         emit_del_line(reset, ecb, data, len);
 730                 } else {
 731                         ecb->lno_in_postimage++;
 732                         emit_add_line(reset, ecb, data, len);
 733                 }
 734                 size -= len;
 735                 data += len;
 736         }
 737         if (!endp) {
 738                 const char *context = diff_get_color(ecb->color_diff,
 739                                                      DIFF_CONTEXT);
 740                 putc('\n', ecb->opt->file);
 741                 emit_line_0(ecb->opt, context, reset, '\\',
 742                             nneof, strlen(nneof));
 743         }
 744 }
 745
 746 static void emit_rewrite_diff(const char *name_a,
 747                               const char *name_b,
 748                               struct diff_filespec *one,
 749                               struct diff_filespec *two,
 750                               struct userdiff_driver *textconv_one,
 751                               struct userdiff_driver *textconv_two,
 752                               struct diff_options *o)
 753 {
 754         int lc_a, lc_b;
 755         const char *name_a_tab, *name_b_tab;
 756         const char *metainfo = diff_get_color(o->use_color, DIFF_METAINFO);
 757         const char *fraginfo = diff_get_color(o->use_color, DIFF_FRAGINFO);
 758         const char *reset = diff_get_color(o->use_color, DIFF_RESET);
 759         static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
 760         const char *a_prefix, *b_prefix;
 761         char *data_one, *data_two;
 762         size_t size_one, size_two;
 763         struct emit_callback ecbdata;
 764         const char *line_prefix = diff_line_prefix(o);
 765
 766         if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
 767                 a_prefix = o->b_prefix;
 768                 b_prefix = o->a_prefix;
 769         } else {
 770                 a_prefix = o->a_prefix;
 771                 b_prefix = o->b_prefix;
 772         }
 773
 774         name_a += (*name_a == '/');
 775         name_b += (*name_b == '/');
 776         name_a_tab = strchr(name_a, ' ') ? "\t" : "";
 777         name_b_tab = strchr(name_b, ' ') ? "\t" : "";
 778
 779         strbuf_reset(&a_name);
 780         strbuf_reset(&b_name);
 781         quote_two_c_style(&a_name, a_prefix, name_a, 0);
 782         quote_two_c_style(&b_name, b_prefix, name_b, 0);
 783
 784         size_one = fill_textconv(textconv_one, one, &data_one);
 785         size_two = fill_textconv(textconv_two, two, &data_two);
 786
 787         memset(&ecbdata, 0, sizeof(ecbdata));
 788         ecbdata.color_diff = want_color(o->use_color);
 789         ecbdata.ws_rule = whitespace_rule(name_b);
 790         ecbdata.opt = o;
 791         if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
 792                 mmfile_t mf1, mf2;
 793                 mf1.ptr = (char *)data_one;
 794                 mf2.ptr = (char *)data_two;
 795                 mf1.size = size_one;
 796                 mf2.size = size_two;
 797                 check_blank_at_eof(&mf1, &mf2, &ecbdata);
 798         }
 799         ecbdata.lno_in_preimage = 1;
 800         ecbdata.lno_in_postimage = 1;
 801
 802         lc_a = count_lines(data_one, size_one);
 803         lc_b = count_lines(data_two, size_two);
 804         fprintf(o->file,
 805                 "%s%s--- %s%s%s\n%s%s+++ %s%s%s\n%s%s@@ -",
 806                 line_prefix, metainfo, a_name.buf, name_a_tab, reset,
 807                 line_prefix, metainfo, b_name.buf, name_b_tab, reset,
 808                 line_prefix, fraginfo);
 809         if (!o->irreversible_delete)
 810                 print_line_count(o->file, lc_a);
 811         else
 812                 fprintf(o->file, "?,?");
 813         fprintf(o->file, " +");
 814         print_line_count(o->file, lc_b);
 815         fprintf(o->file, " @@%s\n", reset);
 816         if (lc_a && !o->irreversible_delete)
 817                 emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
 818         if (lc_b)
 819                 emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
 820         if (textconv_one)
 821                 free((char *)data_one);
 822         if (textconv_two)
 823                 free((char *)data_two);
 824 }
 825
 826 struct diff_words_buffer {
 827         mmfile_t text;
 828         long alloc;
 829         struct diff_words_orig {
 830                 const char *begin, *end;
 831         } *orig;
 832         int orig_nr, orig_alloc;
 833 };
 834
 835 static void diff_words_append(char *line, unsigned long len,
 836                 struct diff_words_buffer *buffer)
 837 {
 838         ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
 839         line++;
 840         len--;
 841         memcpy(buffer->text.ptr + buffer->text.size, line, len);
 842         buffer->text.size += len;
 843         buffer->text.ptr[buffer->text.size] = '\0';
 844 }
 845
 846 struct diff_words_style_elem {
 847         const char *prefix;
 848         const char *suffix;
 849         const char *color; /* NULL; filled in by the setup code if
 850                             * color is enabled */
 851 };
 852
 853 struct diff_words_style {
 854         enum diff_words_type type;
 855         struct diff_words_style_elem new, old, ctx;
 856         const char *newline;
 857 };
 858
 859 static struct diff_words_style diff_words_styles[] = {
 860         { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
 861         { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
 862         { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
 863 };
 864
 865 struct diff_words_data {
 866         struct diff_words_buffer minus, plus;
 867         const char *current_plus;
 868         int last_minus;
 869         struct diff_options *opt;
 870         regex_t *word_regex;
 871         enum diff_words_type type;
 872         struct diff_words_style *style;
 873 };
 874
 875 static int fn_out_diff_words_write_helper(FILE *fp,
 876                                           struct diff_words_style_elem *st_el,
 877                                           const char *newline,
 878                                           size_t count, const char *buf,
 879                                           const char *line_prefix)
 880 {
 881         int print = 0;
 882
 883         while (count) {
 884                 char *p = memchr(buf, '\n', count);
 885                 if (print)
 886                         fputs(line_prefix, fp);
 887                 if (p != buf) {
 888                         if (st_el->color && fputs(st_el->color, fp) < 0)
 889                                 return -1;
 890                         if (fputs(st_el->prefix, fp) < 0 ||
 891                             fwrite(buf, p ? p - buf : count, 1, fp) != 1 ||
 892                             fputs(st_el->suffix, fp) < 0)
 893                                 return -1;
 894                         if (st_el->color && *st_el->color
 895                             && fputs(GIT_COLOR_RESET, fp) < 0)
 896                                 return -1;
 897                 }
 898                 if (!p)
 899                         return 0;
 900                 if (fputs(newline, fp) < 0)
 901                         return -1;
 902                 count -= p + 1 - buf;
 903                 buf = p + 1;
 904                 print = 1;
 905         }
 906         return 0;
 907 }
 908
 909 /*
 910  * '--color-words' algorithm can be described as:
 911  *
 912  *   1. collect the minus/plus lines of a diff hunk, divided into
 913  *      minus-lines and plus-lines;
 914  *
 915  *   2. break both minus-lines and plus-lines into words and
 916  *      place them into two mmfile_t with one word for each line;
 917  *
 918  *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
 919  *
 920  * And for the common parts of the both file, we output the plus side text.
 921  * diff_words->current_plus is used to trace the current position of the plus file
 922  * which printed. diff_words->last_minus is used to trace the last minus word
 923  * printed.
 924  *
 925  * For '--graph' to work with '--color-words', we need to output the graph prefix
 926  * on each line of color words output. Generally, there are two conditions on
 927  * which we should output the prefix.
 928  *
 929  *   1. diff_words->last_minus == 0 &&
 930  *      diff_words->current_plus == diff_words->plus.text.ptr
 931  *
 932  *      that is: the plus text must start as a new line, and if there is no minus
 933  *      word printed, a graph prefix must be printed.
 934  *
 935  *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
 936  *      *(diff_words->current_plus - 1) == '\n'
 937  *
 938  *      that is: a graph prefix must be printed following a '\n'
 939  */
 940 static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
 941 {
 942         if ((diff_words->last_minus == 0 &&
 943                 diff_words->current_plus == diff_words->plus.text.ptr) ||
 944                 (diff_words->current_plus > diff_words->plus.text.ptr &&
 945                 *(diff_words->current_plus - 1) == '\n')) {
 946                 return 1;
 947         } else {
 948                 return 0;
 949         }
 950 }
 951
 952 static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
 953 {
 954         struct diff_words_data *diff_words = priv;
 955         struct diff_words_style *style = diff_words->style;
 956         int minus_first, minus_len, plus_first, plus_len;
 957         const char *minus_begin, *minus_end, *plus_begin, *plus_end;
 958         struct diff_options *opt = diff_words->opt;
 959         const char *line_prefix;
 960
 961         if (line[0] != '@' || parse_hunk_header(line, len,
 962                         &minus_first, &minus_len, &plus_first, &plus_len))
 963                 return;
 964
 965         assert(opt);
 966         line_prefix = diff_line_prefix(opt);
 967
 968         /* POSIX requires that first be decremented by one if len == 0... */
 969         if (minus_len) {
 970                 minus_begin = diff_words->minus.orig[minus_first].begin;
 971                 minus_end =
 972                         diff_words->minus.orig[minus_first + minus_len - 1].end;
 973         } else
 974                 minus_begin = minus_end =
 975                         diff_words->minus.orig[minus_first].end;
 976
 977         if (plus_len) {
 978                 plus_begin = diff_words->plus.orig[plus_first].begin;
 979                 plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
 980         } else
 981                 plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
 982
 983         if (color_words_output_graph_prefix(diff_words)) {
 984                 fputs(line_prefix, diff_words->opt->file);
 985         }
 986         if (diff_words->current_plus != plus_begin) {
 987                 fn_out_diff_words_write_helper(diff_words->opt->file,
 988                                 &style->ctx, style->newline,
 989                                 plus_begin - diff_words->current_plus,
 990                                 diff_words->current_plus, line_prefix);
 991                 if (*(plus_begin - 1) == '\n')
 992                         fputs(line_prefix, diff_words->opt->file);
 993         }
 994         if (minus_begin != minus_end) {
 995                 fn_out_diff_words_write_helper(diff_words->opt->file,
 996                                 &style->old, style->newline,
 997                                 minus_end - minus_begin, minus_begin,
 998                                 line_prefix);
 999         }
1000         if (plus_begin != plus_end) {
1001                 fn_out_diff_words_write_helper(diff_words->opt->file,
1002                                 &style->new, style->newline,
1003                                 plus_end - plus_begin, plus_begin,
1004                                 line_prefix);
1005         }
1006
1007         diff_words->current_plus = plus_end;
1008         diff_words->last_minus = minus_first;
1009 }
1010
1011 /* This function starts looking at *begin, and returns 0 iff a word was found. */
1012 static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
1013                 int *begin, int *end)
1014 {
1015         if (word_regex && *begin < buffer->size) {
1016                 regmatch_t match[1];
1017                 if (!regexec_buf(word_regex, buffer->ptr + *begin,
1018                                  buffer->size - *begin, 1, match, 0)) {
1019                         char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
1020                                         '\n', match[0].rm_eo - match[0].rm_so);
1021                         *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
1022                         *begin += match[0].rm_so;
1023                         return *begin >= *end;
1024                 }
1025                 return -1;
1026         }
1027
1028         /* find the next word */
1029         while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
1030                 (*begin)++;
1031         if (*begin >= buffer->size)
1032                 return -1;
1033
1034         /* find the end of the word */
1035         *end = *begin + 1;
1036         while (*end < buffer->size && !isspace(buffer->ptr[*end]))
1037                 (*end)++;
1038
1039         return 0;
1040 }
1041
1042 /*
1043  * This function splits the words in buffer->text, stores the list with
1044  * newline separator into out, and saves the offsets of the original words
1045  * in buffer->orig.
1046  */
1047 static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
1048                 regex_t *word_regex)
1049 {
1050         int i, j;
1051         long alloc = 0;
1052
1053         out->size = 0;
1054         out->ptr = NULL;
1055
1056         /* fake an empty "0th" word */
1057         ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
1058         buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
1059         buffer->orig_nr = 1;
1060
1061         for (i = 0; i < buffer->text.size; i++) {
1062                 if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
1063                         return;
1064
1065                 /* store original boundaries */
1066                 ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
1067                                 buffer->orig_alloc);
1068                 buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
1069                 buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
1070                 buffer->orig_nr++;
1071
1072                 /* store one word */
1073                 ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
1074                 memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
1075                 out->ptr[out->size + j - i] = '\n';
1076                 out->size += j - i + 1;
1077
1078                 i = j - 1;
1079         }
1080 }
1081
1082 /* this executes the word diff on the accumulated buffers */
1083 static void diff_words_show(struct diff_words_data *diff_words)
1084 {
1085         xpparam_t xpp;
1086         xdemitconf_t xecfg;
1087         mmfile_t minus, plus;
1088         struct diff_words_style *style = diff_words->style;
1089
1090         struct diff_options *opt = diff_words->opt;
1091         const char *line_prefix;
1092
1093         assert(opt);
1094         line_prefix = diff_line_prefix(opt);
1095
1096         /* special case: only removal */
1097         if (!diff_words->plus.text.size) {
1098                 fputs(line_prefix, diff_words->opt->file);
1099                 fn_out_diff_words_write_helper(diff_words->opt->file,
1100                         &style->old, style->newline,
1101                         diff_words->minus.text.size,
1102                         diff_words->minus.text.ptr, line_prefix);
1103                 diff_words->minus.text.size = 0;
1104                 return;
1105         }
1106
1107         diff_words->current_plus = diff_words->plus.text.ptr;
1108         diff_words->last_minus = 0;
1109
1110         memset(&xpp, 0, sizeof(xpp));
1111         memset(&xecfg, 0, sizeof(xecfg));
1112         diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
1113         diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
1114         xpp.flags = 0;
1115         /* as only the hunk header will be parsed, we need a 0-context */
1116         xecfg.ctxlen = 0;
1117         if (xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
1118                           &xpp, &xecfg))
1119                 die("unable to generate word diff");
1120         free(minus.ptr);
1121         free(plus.ptr);
1122         if (diff_words->current_plus != diff_words->plus.text.ptr +
1123                         diff_words->plus.text.size) {
1124                 if (color_words_output_graph_prefix(diff_words))
1125                         fputs(line_prefix, diff_words->opt->file);
1126                 fn_out_diff_words_write_helper(diff_words->opt->file,
1127                         &style->ctx, style->newline,
1128                         diff_words->plus.text.ptr + diff_words->plus.text.size
1129                         - diff_words->current_plus, diff_words->current_plus,
1130                         line_prefix);
1131         }
1132         diff_words->minus.text.size = diff_words->plus.text.size = 0;
1133 }
1134
1135 /* In "color-words" mode, show word-diff of words accumulated in the buffer */
1136 static void diff_words_flush(struct emit_callback *ecbdata)
1137 {
1138         if (ecbdata->diff_words->minus.text.size ||
1139             ecbdata->diff_words->plus.text.size)
1140                 diff_words_show(ecbdata->diff_words);
1141 }
1142
1143 static void diff_filespec_load_driver(struct diff_filespec *one)
1144 {
1145         /* Use already-loaded driver */
1146         if (one->driver)
1147                 return;
1148
1149         if (S_ISREG(one->mode))
1150                 one->driver = userdiff_find_by_path(one->path);
1151
1152         /* Fallback to default settings */
1153         if (!one->driver)
1154                 one->driver = userdiff_find_by_name("default");
1155 }
1156
1157 static const char *userdiff_word_regex(struct diff_filespec *one)
1158 {
1159         diff_filespec_load_driver(one);
1160         return one->driver->word_regex;
1161 }
1162
1163 static void init_diff_words_data(struct emit_callback *ecbdata,
1164                                  struct diff_options *orig_opts,
1165                                  struct diff_filespec *one,
1166                                  struct diff_filespec *two)
1167 {
1168         int i;
1169         struct diff_options *o = xmalloc(sizeof(struct diff_options));
1170         memcpy(o, orig_opts, sizeof(struct diff_options));
1171
1172         ecbdata->diff_words =
1173                 xcalloc(1, sizeof(struct diff_words_data));
1174         ecbdata->diff_words->type = o->word_diff;
1175         ecbdata->diff_words->opt = o;
1176         if (!o->word_regex)
1177                 o->word_regex = userdiff_word_regex(one);
1178         if (!o->word_regex)
1179                 o->word_regex = userdiff_word_regex(two);
1180         if (!o->word_regex)
1181                 o->word_regex = diff_word_regex_cfg;
1182         if (o->word_regex) {
1183                 ecbdata->diff_words->word_regex = (regex_t *)
1184                         xmalloc(sizeof(regex_t));
1185                 if (regcomp(ecbdata->diff_words->word_regex,
1186                             o->word_regex,
1187                             REG_EXTENDED | REG_NEWLINE))
1188                         die ("Invalid regular expression: %s",
1189                              o->word_regex);
1190         }
1191         for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
1192                 if (o->word_diff == diff_words_styles[i].type) {
1193                         ecbdata->diff_words->style =
1194                                 &diff_words_styles[i];
1195                         break;
1196                 }
1197         }
1198         if (want_color(o->use_color)) {
1199                 struct diff_words_style *st = ecbdata->diff_words->style;
1200                 st->old.color = diff_get_color_opt(o, DIFF_FILE_OLD);
1201                 st->new.color = diff_get_color_opt(o, DIFF_FILE_NEW);
1202                 st->ctx.color = diff_get_color_opt(o, DIFF_CONTEXT);
1203         }
1204 }
1205
1206 static void free_diff_words_data(struct emit_callback *ecbdata)
1207 {
1208         if (ecbdata->diff_words) {
1209                 diff_words_flush(ecbdata);
1210                 free (ecbdata->diff_words->opt);
1211                 free (ecbdata->diff_words->minus.text.ptr);
1212                 free (ecbdata->diff_words->minus.orig);
1213                 free (ecbdata->diff_words->plus.text.ptr);
1214                 free (ecbdata->diff_words->plus.orig);
1215                 if (ecbdata->diff_words->word_regex) {
1216                         regfree(ecbdata->diff_words->word_regex);
1217                         free(ecbdata->diff_words->word_regex);
1218                 }
1219                 FREE_AND_NULL(ecbdata->diff_words);
1220         }
1221 }
1222
1223 const char *diff_get_color(int diff_use_color, enum color_diff ix)
1224 {
1225         if (want_color(diff_use_color))
1226                 return diff_colors[ix];
1227         return "";
1228 }
1229
1230 const char *diff_line_prefix(struct diff_options *opt)
1231 {
1232         struct strbuf *msgbuf;
1233         if (!opt->output_prefix)
1234                 return "";
1235
1236         msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
1237         return msgbuf->buf;
1238 }
1239
1240 static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
1241 {
1242         const char *cp;
1243         unsigned long allot;
1244         size_t l = len;
1245
1246         if (ecb->truncate)
1247                 return ecb->truncate(line, len);
1248         cp = line;
1249         allot = l;
1250         while (0 < l) {
1251                 (void) utf8_width(&cp, &l);
1252                 if (!cp)
1253                         break; /* truncated in the middle? */
1254         }
1255         return allot - l;
1256 }
1257
1258 static void find_lno(const char *line, struct emit_callback *ecbdata)
1259 {
1260         const char *p;
1261         ecbdata->lno_in_preimage = 0;
1262         ecbdata->lno_in_postimage = 0;
1263         p = strchr(line, '-');
1264         if (!p)
1265                 return; /* cannot happen */
1266         ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
1267         p = strchr(p, '+');
1268         if (!p)
1269                 return; /* cannot happen */
1270         ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
1271 }
1272
1273 static void fn_out_consume(void *priv, char *line, unsigned long len)
1274 {
1275         struct emit_callback *ecbdata = priv;
1276         const char *meta = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
1277         const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
1278         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1279         struct diff_options *o = ecbdata->opt;
1280         const char *line_prefix = diff_line_prefix(o);
1281
1282         o->found_changes = 1;
1283
1284         if (ecbdata->header) {
1285                 fprintf(o->file, "%s", ecbdata->header->buf);
1286                 strbuf_reset(ecbdata->header);
1287                 ecbdata->header = NULL;
1288         }
1289
1290         if (ecbdata->label_path[0]) {
1291                 const char *name_a_tab, *name_b_tab;
1292
1293                 name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
1294                 name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
1295
1296                 fprintf(o->file, "%s%s--- %s%s%s\n",
1297                         line_prefix, meta, ecbdata->label_path[0], reset, name_a_tab);
1298                 fprintf(o->file, "%s%s+++ %s%s%s\n",
1299                         line_prefix, meta, ecbdata->label_path[1], reset, name_b_tab);
1300                 ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
1301         }
1302
1303         if (diff_suppress_blank_empty
1304             && len == 2 && line[0] == ' ' && line[1] == '\n') {
1305                 line[0] = '\n';
1306                 len = 1;
1307         }
1308
1309         if (line[0] == '@') {
1310                 if (ecbdata->diff_words)
1311                         diff_words_flush(ecbdata);
1312                 len = sane_truncate_line(ecbdata, line, len);
1313                 find_lno(line, ecbdata);
1314                 emit_hunk_header(ecbdata, line, len);
1315                 if (line[len-1] != '\n')
1316                         putc('\n', o->file);
1317                 return;
1318         }
1319
1320         if (ecbdata->diff_words) {
1321                 if (line[0] == '-') {
1322                         diff_words_append(line, len,
1323                                           &ecbdata->diff_words->minus);
1324                         return;
1325                 } else if (line[0] == '+') {
1326                         diff_words_append(line, len,
1327                                           &ecbdata->diff_words->plus);
1328                         return;
1329                 } else if (starts_with(line, "\\ ")) {
1330                         /*
1331                          * Eat the "no newline at eof" marker as if we
1332                          * saw a "+" or "-" line with nothing on it,
1333                          * and return without diff_words_flush() to
1334                          * defer processing. If this is the end of
1335                          * preimage, more "+" lines may come after it.
1336                          */
1337                         return;
1338                 }
1339                 diff_words_flush(ecbdata);
1340                 if (ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN) {
1341                         emit_line(o, context, reset, line, len);
1342                         fputs("~\n", o->file);
1343                 } else {
1344                         /*
1345                          * Skip the prefix character, if any.  With
1346                          * diff_suppress_blank_empty, there may be
1347                          * none.
1348                          */
1349                         if (line[0] != '\n') {
1350                               line++;
1351                               len--;
1352                         }
1353                         emit_line(o, context, reset, line, len);
1354                 }
1355                 return;
1356         }
1357
1358         switch (line[0]) {
1359         case '+':
1360                 ecbdata->lno_in_postimage++;
1361                 emit_add_line(reset, ecbdata, line + 1, len - 1);
1362                 break;
1363         case '-':
1364                 ecbdata->lno_in_preimage++;
1365                 emit_del_line(reset, ecbdata, line + 1, len - 1);
1366                 break;
1367         case ' ':
1368                 ecbdata->lno_in_postimage++;
1369                 ecbdata->lno_in_preimage++;
1370                 emit_context_line(reset, ecbdata, line + 1, len - 1);
1371                 break;
1372         default:
1373                 /* incomplete line at the end */
1374                 ecbdata->lno_in_preimage++;
1375                 emit_line(o, diff_get_color(ecbdata->color_diff, DIFF_CONTEXT),
1376                           reset, line, len);
1377                 break;
1378         }
1379 }
1380
1381 static char *pprint_rename(const char *a, const char *b)
1382 {
1383         const char *old = a;
1384         const char *new = b;
1385         struct strbuf name = STRBUF_INIT;
1386         int pfx_length, sfx_length;
1387         int pfx_adjust_for_slash;
1388         int len_a = strlen(a);
1389         int len_b = strlen(b);
1390         int a_midlen, b_midlen;
1391         int qlen_a = quote_c_style(a, NULL, NULL, 0);
1392         int qlen_b = quote_c_style(b, NULL, NULL, 0);
1393
1394         if (qlen_a || qlen_b) {
1395                 quote_c_style(a, &name, NULL, 0);
1396                 strbuf_addstr(&name, " => ");
1397                 quote_c_style(b, &name, NULL, 0);
1398                 return strbuf_detach(&name, NULL);
1399         }
1400
1401         /* Find common prefix */
1402         pfx_length = 0;
1403         while (*old && *new && *old == *new) {
1404                 if (*old == '/')
1405                         pfx_length = old - a + 1;
1406                 old++;
1407                 new++;
1408         }
1409
1410         /* Find common suffix */
1411         old = a + len_a;
1412         new = b + len_b;
1413         sfx_length = 0;
1414         /*
1415          * If there is a common prefix, it must end in a slash.  In
1416          * that case we let this loop run 1 into the prefix to see the
1417          * same slash.
1418          *
1419          * If there is no common prefix, we cannot do this as it would
1420          * underrun the input strings.
1421          */
1422         pfx_adjust_for_slash = (pfx_length ? 1 : 0);
1423         while (a + pfx_length - pfx_adjust_for_slash <= old &&
1424                b + pfx_length - pfx_adjust_for_slash <= new &&
1425                *old == *new) {
1426                 if (*old == '/')
1427                         sfx_length = len_a - (old - a);
1428                 old--;
1429                 new--;
1430         }
1431
1432         /*
1433          * pfx{mid-a => mid-b}sfx
1434          * {pfx-a => pfx-b}sfx
1435          * pfx{sfx-a => sfx-b}
1436          * name-a => name-b
1437          */
1438         a_midlen = len_a - pfx_length - sfx_length;
1439         b_midlen = len_b - pfx_length - sfx_length;
1440         if (a_midlen < 0)
1441                 a_midlen = 0;
1442         if (b_midlen < 0)
1443                 b_midlen = 0;
1444
1445         strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
1446         if (pfx_length + sfx_length) {
1447                 strbuf_add(&name, a, pfx_length);
1448                 strbuf_addch(&name, '{');
1449         }
1450         strbuf_add(&name, a + pfx_length, a_midlen);
1451         strbuf_addstr(&name, " => ");
1452         strbuf_add(&name, b + pfx_length, b_midlen);
1453         if (pfx_length + sfx_length) {
1454                 strbuf_addch(&name, '}');
1455                 strbuf_add(&name, a + len_a - sfx_length, sfx_length);
1456         }
1457         return strbuf_detach(&name, NULL);
1458 }
1459
1460 struct diffstat_t {
1461         int nr;
1462         int alloc;
1463         struct diffstat_file {
1464                 char *from_name;
1465                 char *name;
1466                 char *print_name;
1467                 unsigned is_unmerged:1;
1468                 unsigned is_binary:1;
1469                 unsigned is_renamed:1;
1470                 unsigned is_interesting:1;
1471                 uintmax_t added, deleted;
1472         } **files;
1473 };
1474
1475 static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
1476                                           const char *name_a,
1477                                           const char *name_b)
1478 {
1479         struct diffstat_file *x;
1480         x = xcalloc(1, sizeof(*x));
1481         ALLOC_GROW(diffstat->files, diffstat->nr + 1, diffstat->alloc);
1482         diffstat->files[diffstat->nr++] = x;
1483         if (name_b) {
1484                 x->from_name = xstrdup(name_a);
1485                 x->name = xstrdup(name_b);
1486                 x->is_renamed = 1;
1487         }
1488         else {
1489                 x->from_name = NULL;
1490                 x->name = xstrdup(name_a);
1491         }
1492         return x;
1493 }
1494
1495 static void diffstat_consume(void *priv, char *line, unsigned long len)
1496 {
1497         struct diffstat_t *diffstat = priv;
1498         struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
1499
1500         if (line[0] == '+')
1501                 x->added++;
1502         else if (line[0] == '-')
1503                 x->deleted++;
1504 }
1505
1506 const char mime_boundary_leader[] = "------------";
1507
1508 static int scale_linear(int it, int width, int max_change)
1509 {
1510         if (!it)
1511                 return 0;
1512         /*
1513          * make sure that at least one '-' or '+' is printed if
1514          * there is any change to this path. The easiest way is to
1515          * scale linearly as if the alloted width is one column shorter
1516          * than it is, and then add 1 to the result.
1517          */
1518         return 1 + (it * (width - 1) / max_change);
1519 }
1520
1521 static void show_name(FILE *file,
1522                       const char *prefix, const char *name, int len)
1523 {
1524         fprintf(file, " %s%-*s |", prefix, len, name);
1525 }
1526
1527 static void show_graph(FILE *file, char ch, int cnt, const char *set, const char *reset)
1528 {
1529         if (cnt <= 0)
1530                 return;
1531         fprintf(file, "%s", set);
1532         while (cnt--)
1533                 putc(ch, file);
1534         fprintf(file, "%s", reset);
1535 }
1536
1537 static void fill_print_name(struct diffstat_file *file)
1538 {
1539         char *pname;
1540
1541         if (file->print_name)
1542                 return;
1543
1544         if (!file->is_renamed) {
1545                 struct strbuf buf = STRBUF_INIT;
1546                 if (quote_c_style(file->name, &buf, NULL, 0)) {
1547                         pname = strbuf_detach(&buf, NULL);
1548                 } else {
1549                         pname = file->name;
1550                         strbuf_release(&buf);
1551                 }
1552         } else {
1553                 pname = pprint_rename(file->from_name, file->name);
1554         }
1555         file->print_name = pname;
1556 }
1557
1558 int print_stat_summary(FILE *fp, int files, int insertions, int deletions)
1559 {
1560         struct strbuf sb = STRBUF_INIT;
1561         int ret;
1562
1563         if (!files) {
1564                 assert(insertions == 0 && deletions == 0);
1565                 return fprintf(fp, "%s\n", " 0 files changed");
1566         }
1567
1568         strbuf_addf(&sb,
1569                     (files == 1) ? " %d file changed" : " %d files changed",
1570                     files);
1571
1572         /*
1573          * For binary diff, the caller may want to print "x files
1574          * changed" with insertions == 0 && deletions == 0.
1575          *
1576          * Not omitting "0 insertions(+), 0 deletions(-)" in this case
1577          * is probably less confusing (i.e skip over "2 files changed
1578          * but nothing about added/removed lines? Is this a bug in Git?").
1579          */
1580         if (insertions || deletions == 0) {
1581                 strbuf_addf(&sb,
1582                             (insertions == 1) ? ", %d insertion(+)" : ", %d insertions(+)",
1583                             insertions);
1584         }
1585
1586         if (deletions || insertions == 0) {
1587                 strbuf_addf(&sb,
1588                             (deletions == 1) ? ", %d deletion(-)" : ", %d deletions(-)",
1589                             deletions);
1590         }
1591         strbuf_addch(&sb, '\n');
1592         ret = fputs(sb.buf, fp);
1593         strbuf_release(&sb);
1594         return ret;
1595 }
1596
1597 static void show_stats(struct diffstat_t *data, struct diff_options *options)
1598 {
1599         int i, len, add, del, adds = 0, dels = 0;
1600         uintmax_t max_change = 0, max_len = 0;
1601         int total_files = data->nr, count;
1602         int width, name_width, graph_width, number_width = 0, bin_width = 0;
1603         const char *reset, *add_c, *del_c;
1604         const char *line_prefix = "";
1605         int extra_shown = 0;
1606
1607         if (data->nr == 0)
1608                 return;
1609
1610         line_prefix = diff_line_prefix(options);
1611         count = options->stat_count ? options->stat_count : data->nr;
1612
1613         reset = diff_get_color_opt(options, DIFF_RESET);
1614         add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
1615         del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
1616
1617         /*
1618          * Find the longest filename and max number of changes
1619          */
1620         for (i = 0; (i < count) && (i < data->nr); i++) {
1621                 struct diffstat_file *file = data->files[i];
1622                 uintmax_t change = file->added + file->deleted;
1623
1624                 if (!file->is_interesting && (change == 0)) {
1625                         count++; /* not shown == room for one more */
1626                         continue;
1627                 }
1628                 fill_print_name(file);
1629                 len = strlen(file->print_name);
1630                 if (max_len < len)
1631                         max_len = len;
1632
1633                 if (file->is_unmerged) {
1634                         /* "Unmerged" is 8 characters */
1635                         bin_width = bin_width < 8 ? 8 : bin_width;
1636                         continue;
1637                 }
1638                 if (file->is_binary) {
1639                         /* "Bin XXX -> YYY bytes" */
1640                         int w = 14 + decimal_width(file->added)
1641                                 + decimal_width(file->deleted);
1642                         bin_width = bin_width < w ? w : bin_width;
1643                         /* Display change counts aligned with "Bin" */
1644                         number_width = 3;
1645                         continue;
1646                 }
1647
1648                 if (max_change < change)
1649                         max_change = change;
1650         }
1651         count = i; /* where we can stop scanning in data->files[] */
1652
1653         /*
1654          * We have width = stat_width or term_columns() columns total.
1655          * We want a maximum of min(max_len, stat_name_width) for the name part.
1656          * We want a maximum of min(max_change, stat_graph_width) for the +- part.
1657          * We also need 1 for " " and 4 + decimal_width(max_change)
1658          * for " | NNNN " and one the empty column at the end, altogether
1659          * 6 + decimal_width(max_change).
1660          *
1661          * If there's not enough space, we will use the smaller of
1662          * stat_name_width (if set) and 5/8*width for the filename,
1663          * and the rest for constant elements + graph part, but no more
1664          * than stat_graph_width for the graph part.
1665          * (5/8 gives 50 for filename and 30 for the constant parts + graph
1666          * for the standard terminal size).
1667          *
1668          * In other words: stat_width limits the maximum width, and
1669          * stat_name_width fixes the maximum width of the filename,
1670          * and is also used to divide available columns if there
1671          * aren't enough.
1672          *
1673          * Binary files are displayed with "Bin XXX -> YYY bytes"
1674          * instead of the change count and graph. This part is treated
1675          * similarly to the graph part, except that it is not
1676          * "scaled". If total width is too small to accommodate the
1677          * guaranteed minimum width of the filename part and the
1678          * separators and this message, this message will "overflow"
1679          * making the line longer than the maximum width.
1680          */
1681
1682         if (options->stat_width == -1)
1683                 width = term_columns() - strlen(line_prefix);
1684         else
1685                 width = options->stat_width ? options->stat_width : 80;
1686         number_width = decimal_width(max_change) > number_width ?
1687                 decimal_width(max_change) : number_width;
1688
1689         if (options->stat_graph_width == -1)
1690                 options->stat_graph_width = diff_stat_graph_width;
1691
1692         /*
1693          * Guarantee 3/8*16==6 for the graph part
1694          * and 5/8*16==10 for the filename part
1695          */
1696         if (width < 16 + 6 + number_width)
1697                 width = 16 + 6 + number_width;
1698
1699         /*
1700          * First assign sizes that are wanted, ignoring available width.
1701          * strlen("Bin XXX -> YYY bytes") == bin_width, and the part
1702          * starting from "XXX" should fit in graph_width.
1703          */
1704         graph_width = max_change + 4 > bin_width ? max_change : bin_width - 4;
1705         if (options->stat_graph_width &&
1706             options->stat_graph_width < graph_width)
1707                 graph_width = options->stat_graph_width;
1708
1709         name_width = (options->stat_name_width > 0 &&
1710                       options->stat_name_width < max_len) ?
1711                 options->stat_name_width : max_len;
1712
1713         /*
1714          * Adjust adjustable widths not to exceed maximum width
1715          */
1716         if (name_width + number_width + 6 + graph_width > width) {
1717                 if (graph_width > width * 3/8 - number_width - 6) {
1718                         graph_width = width * 3/8 - number_width - 6;
1719                         if (graph_width < 6)
1720                                 graph_width = 6;
1721                 }
1722
1723                 if (options->stat_graph_width &&
1724                     graph_width > options->stat_graph_width)
1725                         graph_width = options->stat_graph_width;
1726                 if (name_width > width - number_width - 6 - graph_width)
1727                         name_width = width - number_width - 6 - graph_width;
1728                 else
1729                         graph_width = width - number_width - 6 - name_width;
1730         }
1731
1732         /*
1733          * From here name_width is the width of the name area,
1734          * and graph_width is the width of the graph area.
1735          * max_change is used to scale graph properly.
1736          */
1737         for (i = 0; i < count; i++) {
1738                 const char *prefix = "";
1739                 struct diffstat_file *file = data->files[i];
1740                 char *name = file->print_name;
1741                 uintmax_t added = file->added;
1742                 uintmax_t deleted = file->deleted;
1743                 int name_len;
1744
1745                 if (!file->is_interesting && (added + deleted == 0))
1746                         continue;
1747
1748                 /*
1749                  * "scale" the filename
1750                  */
1751                 len = name_width;
1752                 name_len = strlen(name);
1753                 if (name_width < name_len) {
1754                         char *slash;
1755                         prefix = "...";
1756                         len -= 3;
1757                         name += name_len - len;
1758                         slash = strchr(name, '/');
1759                         if (slash)
1760                                 name = slash;
1761                 }
1762
1763                 if (file->is_binary) {
1764                         fprintf(options->file, "%s", line_prefix);
1765                         show_name(options->file, prefix, name, len);
1766                         fprintf(options->file, " %*s", number_width, "Bin");
1767                         if (!added && !deleted) {
1768                                 putc('\n', options->file);
1769                                 continue;
1770                         }
1771                         fprintf(options->file, " %s%"PRIuMAX"%s",
1772                                 del_c, deleted, reset);
1773                         fprintf(options->file, " -> ");
1774                         fprintf(options->file, "%s%"PRIuMAX"%s",
1775                                 add_c, added, reset);
1776                         fprintf(options->file, " bytes");
1777                         fprintf(options->file, "\n");
1778                         continue;
1779                 }
1780                 else if (file->is_unmerged) {
1781                         fprintf(options->file, "%s", line_prefix);
1782                         show_name(options->file, prefix, name, len);
1783                         fprintf(options->file, " Unmerged\n");
1784                         continue;
1785                 }
1786
1787                 /*
1788                  * scale the add/delete
1789                  */
1790                 add = added;
1791                 del = deleted;
1792
1793                 if (graph_width <= max_change) {
1794                         int total = scale_linear(add + del, graph_width, max_change);
1795                         if (total < 2 && add && del)
1796                                 /* width >= 2 due to the sanity check */
1797                                 total = 2;
1798                         if (add < del) {
1799                                 add = scale_linear(add, graph_width, max_change);
1800                                 del = total - add;
1801                         } else {
1802                                 del = scale_linear(del, graph_width, max_change);
1803                                 add = total - del;
1804                         }
1805                 }
1806                 fprintf(options->file, "%s", line_prefix);
1807                 show_name(options->file, prefix, name, len);
1808                 fprintf(options->file, " %*"PRIuMAX"%s",
1809                         number_width, added + deleted,
1810                         added + deleted ? " " : "");
1811                 show_graph(options->file, '+', add, add_c, reset);
1812                 show_graph(options->file, '-', del, del_c, reset);
1813                 fprintf(options->file, "\n");
1814         }
1815
1816         for (i = 0; i < data->nr; i++) {
1817                 struct diffstat_file *file = data->files[i];
1818                 uintmax_t added = file->added;
1819                 uintmax_t deleted = file->deleted;
1820
1821                 if (file->is_unmerged ||
1822                     (!file->is_interesting && (added + deleted == 0))) {
1823                         total_files--;
1824                         continue;
1825                 }
1826
1827                 if (!file->is_binary) {
1828                         adds += added;
1829                         dels += deleted;
1830                 }
1831                 if (i < count)
1832                         continue;
1833                 if (!extra_shown)
1834                         fprintf(options->file, "%s ...\n", line_prefix);
1835                 extra_shown = 1;
1836         }
1837         fprintf(options->file, "%s", line_prefix);
1838         print_stat_summary(options->file, total_files, adds, dels);
1839 }
1840
1841 static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
1842 {
1843         int i, adds = 0, dels = 0, total_files = data->nr;
1844
1845         if (data->nr == 0)
1846                 return;
1847
1848         for (i = 0; i < data->nr; i++) {
1849                 int added = data->files[i]->added;
1850                 int deleted= data->files[i]->deleted;
1851
1852                 if (data->files[i]->is_unmerged ||
1853                     (!data->files[i]->is_interesting && (added + deleted == 0))) {
1854                         total_files--;
1855                 } else if (!data->files[i]->is_binary) { /* don't count bytes */
1856                         adds += added;
1857                         dels += deleted;
1858                 }
1859         }
1860         fprintf(options->file, "%s", diff_line_prefix(options));
1861         print_stat_summary(options->file, total_files, adds, dels);
1862 }
1863
1864 static void show_numstat(struct diffstat_t *data, struct diff_options *options)
1865 {
1866         int i;
1867
1868         if (data->nr == 0)
1869                 return;
1870
1871         for (i = 0; i < data->nr; i++) {
1872                 struct diffstat_file *file = data->files[i];
1873
1874                 fprintf(options->file, "%s", diff_line_prefix(options));
1875
1876                 if (file->is_binary)
1877                         fprintf(options->file, "-\t-\t");
1878                 else
1879                         fprintf(options->file,
1880                                 "%"PRIuMAX"\t%"PRIuMAX"\t",
1881                                 file->added, file->deleted);
1882                 if (options->line_termination) {
1883                         fill_print_name(file);
1884                         if (!file->is_renamed)
1885                                 write_name_quoted(file->name, options->file,
1886                                                   options->line_termination);
1887                         else {
1888                                 fputs(file->print_name, options->file);
1889                                 putc(options->line_termination, options->file);
1890                         }
1891                 } else {
1892                         if (file->is_renamed) {
1893                                 putc('\0', options->file);
1894                                 write_name_quoted(file->from_name, options->file, '\0');
1895                         }
1896                         write_name_quoted(file->name, options->file, '\0');
1897                 }
1898         }
1899 }
1900
1901 struct dirstat_file {
1902         const char *name;
1903         unsigned long changed;
1904 };
1905
1906 struct dirstat_dir {
1907         struct dirstat_file *files;
1908         int alloc, nr, permille, cumulative;
1909 };
1910
1911 static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
1912                 unsigned long changed, const char *base, int baselen)
1913 {
1914         unsigned long this_dir = 0;
1915         unsigned int sources = 0;
1916         const char *line_prefix = diff_line_prefix(opt);
1917
1918         while (dir->nr) {
1919                 struct dirstat_file *f = dir->files;
1920                 int namelen = strlen(f->name);
1921                 unsigned long this;
1922                 char *slash;
1923
1924                 if (namelen < baselen)
1925                         break;
1926                 if (memcmp(f->name, base, baselen))
1927                         break;
1928                 slash = strchr(f->name + baselen, '/');
1929                 if (slash) {
1930                         int newbaselen = slash + 1 - f->name;
1931                         this = gather_dirstat(opt, dir, changed, f->name, newbaselen);
1932                         sources++;
1933                 } else {
1934                         this = f->changed;
1935                         dir->files++;
1936                         dir->nr--;
1937                         sources += 2;
1938                 }
1939                 this_dir += this;
1940         }
1941
1942         /*
1943          * We don't report dirstat's for
1944          *  - the top level
1945          *  - or cases where everything came from a single directory
1946          *    under this directory (sources == 1).
1947          */
1948         if (baselen && sources != 1) {
1949                 if (this_dir) {
1950                         int permille = this_dir * 1000 / changed;
1951                         if (permille >= dir->permille) {
1952                                 fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
1953                                         permille / 10, permille % 10, baselen, base);
1954                                 if (!dir->cumulative)
1955                                         return 0;
1956                         }
1957                 }
1958         }
1959         return this_dir;
1960 }
1961
1962 static int dirstat_compare(const void *_a, const void *_b)
1963 {
1964         const struct dirstat_file *a = _a;
1965         const struct dirstat_file *b = _b;
1966         return strcmp(a->name, b->name);
1967 }
1968
1969 static void show_dirstat(struct diff_options *options)
1970 {
1971         int i;
1972         unsigned long changed;
1973         struct dirstat_dir dir;
1974         struct diff_queue_struct *q = &diff_queued_diff;
1975
1976         dir.files = NULL;
1977         dir.alloc = 0;
1978         dir.nr = 0;
1979         dir.permille = options->dirstat_permille;
1980         dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1981
1982         changed = 0;
1983         for (i = 0; i < q->nr; i++) {
1984                 struct diff_filepair *p = q->queue[i];
1985                 const char *name;
1986                 unsigned long copied, added, damage;
1987                 int content_changed;
1988
1989                 name = p->two->path ? p->two->path : p->one->path;
1990
1991                 if (p->one->oid_valid && p->two->oid_valid)
1992                         content_changed = oidcmp(&p->one->oid, &p->two->oid);
1993                 else
1994                         content_changed = 1;
1995
1996                 if (!content_changed) {
1997                         /*
1998                          * The SHA1 has not changed, so pre-/post-content is
1999                          * identical. We can therefore skip looking at the
2000                          * file contents altogether.
2001                          */
2002                         damage = 0;
2003                         goto found_damage;
2004                 }
2005
2006                 if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE)) {
2007                         /*
2008                          * In --dirstat-by-file mode, we don't really need to
2009                          * look at the actual file contents at all.
2010                          * The fact that the SHA1 changed is enough for us to
2011                          * add this file to the list of results
2012                          * (with each file contributing equal damage).
2013                          */
2014                         damage = 1;
2015                         goto found_damage;
2016                 }
2017
2018                 if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
2019                         diff_populate_filespec(p->one, 0);
2020                         diff_populate_filespec(p->two, 0);
2021                         diffcore_count_changes(p->one, p->two, NULL, NULL,
2022                                                &copied, &added);
2023                         diff_free_filespec_data(p->one);
2024                         diff_free_filespec_data(p->two);
2025                 } else if (DIFF_FILE_VALID(p->one)) {
2026                         diff_populate_filespec(p->one, CHECK_SIZE_ONLY);
2027                         copied = added = 0;
2028                         diff_free_filespec_data(p->one);
2029                 } else if (DIFF_FILE_VALID(p->two)) {
2030                         diff_populate_filespec(p->two, CHECK_SIZE_ONLY);
2031                         copied = 0;
2032                         added = p->two->size;
2033                         diff_free_filespec_data(p->two);
2034                 } else
2035                         continue;
2036
2037                 /*
2038                  * Original minus copied is the removed material,
2039                  * added is the new material.  They are both damages
2040                  * made to the preimage.
2041                  * If the resulting damage is zero, we know that
2042                  * diffcore_count_changes() considers the two entries to
2043                  * be identical, but since content_changed is true, we
2044                  * know that there must have been _some_ kind of change,
2045                  * so we force all entries to have damage > 0.
2046                  */
2047                 damage = (p->one->size - copied) + added;
2048                 if (!damage)
2049                         damage = 1;
2050
2051 found_damage:
2052                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
2053                 dir.files[dir.nr].name = name;
2054                 dir.files[dir.nr].changed = damage;
2055                 changed += damage;
2056                 dir.nr++;
2057         }
2058
2059         /* This can happen even with many files, if everything was renames */
2060         if (!changed)
2061                 return;
2062
2063         /* Show all directories with more than x% of the changes */
2064         QSORT(dir.files, dir.nr, dirstat_compare);
2065         gather_dirstat(options, &dir, changed, "", 0);
2066 }
2067
2068 static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
2069 {
2070         int i;
2071         unsigned long changed;
2072         struct dirstat_dir dir;
2073
2074         if (data->nr == 0)
2075                 return;
2076
2077         dir.files = NULL;
2078         dir.alloc = 0;
2079         dir.nr = 0;
2080         dir.permille = options->dirstat_permille;
2081         dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
2082
2083         changed = 0;
2084         for (i = 0; i < data->nr; i++) {
2085                 struct diffstat_file *file = data->files[i];
2086                 unsigned long damage = file->added + file->deleted;
2087                 if (file->is_binary)
2088                         /*
2089                          * binary files counts bytes, not lines. Must find some
2090                          * way to normalize binary bytes vs. textual lines.
2091                          * The following heuristic assumes that there are 64
2092                          * bytes per "line".
2093                          * This is stupid and ugly, but very cheap...
2094                          */
2095                         damage = DIV_ROUND_UP(damage, 64);
2096                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
2097                 dir.files[dir.nr].name = file->name;
2098                 dir.files[dir.nr].changed = damage;
2099                 changed += damage;
2100                 dir.nr++;
2101         }
2102
2103         /* This can happen even with many files, if everything was renames */
2104         if (!changed)
2105                 return;
2106
2107         /* Show all directories with more than x% of the changes */
2108         QSORT(dir.files, dir.nr, dirstat_compare);
2109         gather_dirstat(options, &dir, changed, "", 0);
2110 }
2111
2112 static void free_diffstat_info(struct diffstat_t *diffstat)
2113 {
2114         int i;
2115         for (i = 0; i < diffstat->nr; i++) {
2116                 struct diffstat_file *f = diffstat->files[i];
2117                 if (f->name != f->print_name)
2118                         free(f->print_name);
2119                 free(f->name);
2120                 free(f->from_name);
2121                 free(f);
2122         }
2123         free(diffstat->files);
2124 }
2125
2126 struct checkdiff_t {
2127         const char *filename;
2128         int lineno;
2129         int conflict_marker_size;
2130         struct diff_options *o;
2131         unsigned ws_rule;
2132         unsigned status;
2133 };
2134
2135 static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
2136 {
2137         char firstchar;
2138         int cnt;
2139
2140         if (len < marker_size + 1)
2141                 return 0;
2142         firstchar = line[0];
2143         switch (firstchar) {
2144         case '=': case '>': case '<': case '|':
2145                 break;
2146         default:
2147                 return 0;
2148         }
2149         for (cnt = 1; cnt < marker_size; cnt++)
2150                 if (line[cnt] != firstchar)
2151                         return 0;
2152         /* line[1] thru line[marker_size-1] are same as firstchar */
2153         if (len < marker_size + 1 || !isspace(line[marker_size]))
2154                 return 0;
2155         return 1;
2156 }
2157
2158 static void checkdiff_consume(void *priv, char *line, unsigned long len)
2159 {
2160         struct checkdiff_t *data = priv;
2161         int marker_size = data->conflict_marker_size;
2162         const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
2163         const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
2164         const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
2165         char *err;
2166         const char *line_prefix;
2167
2168         assert(data->o);
2169         line_prefix = diff_line_prefix(data->o);
2170
2171         if (line[0] == '+') {
2172                 unsigned bad;
2173                 data->lineno++;
2174                 if (is_conflict_marker(line + 1, marker_size, len - 1)) {
2175                         data->status |= 1;
2176                         fprintf(data->o->file,
2177                                 "%s%s:%d: leftover conflict marker\n",
2178                                 line_prefix, data->filename, data->lineno);
2179                 }
2180                 bad = ws_check(line + 1, len - 1, data->ws_rule);
2181                 if (!bad)
2182                         return;
2183                 data->status |= bad;
2184                 err = whitespace_error_string(bad);
2185                 fprintf(data->o->file, "%s%s:%d: %s.\n",
2186                         line_prefix, data->filename, data->lineno, err);
2187                 free(err);
2188                 emit_line(data->o, set, reset, line, 1);
2189                 ws_check_emit(line + 1, len - 1, data->ws_rule,
2190                               data->o->file, set, reset, ws);
2191         } else if (line[0] == ' ') {
2192                 data->lineno++;
2193         } else if (line[0] == '@') {
2194                 char *plus = strchr(line, '+');
2195                 if (plus)
2196                         data->lineno = strtol(plus, NULL, 10) - 1;
2197                 else
2198                         die("invalid diff");
2199         }
2200 }
2201
2202 static unsigned char *deflate_it(char *data,
2203                                  unsigned long size,
2204                                  unsigned long *result_size)
2205 {
2206         int bound;
2207         unsigned char *deflated;
2208         git_zstream stream;
2209
2210         git_deflate_init(&stream, zlib_compression_level);
2211         bound = git_deflate_bound(&stream, size);
2212         deflated = xmalloc(bound);
2213         stream.next_out = deflated;
2214         stream.avail_out = bound;
2215
2216         stream.next_in = (unsigned char *)data;
2217         stream.avail_in = size;
2218         while (git_deflate(&stream, Z_FINISH) == Z_OK)
2219                 ; /* nothing */
2220         git_deflate_end(&stream);
2221         *result_size = stream.total_out;
2222         return deflated;
2223 }
2224
2225 static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two,
2226                                   const char *prefix)
2227 {
2228         void *cp;
2229         void *delta;
2230         void *deflated;
2231         void *data;
2232         unsigned long orig_size;
2233         unsigned long delta_size;
2234         unsigned long deflate_size;
2235         unsigned long data_size;
2236
2237         /* We could do deflated delta, or we could do just deflated two,
2238          * whichever is smaller.
2239          */
2240         delta = NULL;
2241         deflated = deflate_it(two->ptr, two->size, &deflate_size);
2242         if (one->size && two->size) {
2243                 delta = diff_delta(one->ptr, one->size,
2244                                    two->ptr, two->size,
2245                                    &delta_size, deflate_size);
2246                 if (delta) {
2247                         void *to_free = delta;
2248                         orig_size = delta_size;
2249                         delta = deflate_it(delta, delta_size, &delta_size);
2250                         free(to_free);
2251                 }
2252         }
2253
2254         if (delta && delta_size < deflate_size) {
2255                 fprintf(file, "%sdelta %lu\n", prefix, orig_size);
2256                 free(deflated);
2257                 data = delta;
2258                 data_size = delta_size;
2259         }
2260         else {
2261                 fprintf(file, "%sliteral %lu\n", prefix, two->size);
2262                 free(delta);
2263                 data = deflated;
2264                 data_size = deflate_size;
2265         }
2266
2267         /* emit data encoded in base85 */
2268         cp = data;
2269         while (data_size) {
2270                 int bytes = (52 < data_size) ? 52 : data_size;
2271                 char line[70];
2272                 data_size -= bytes;
2273                 if (bytes <= 26)
2274                         line[0] = bytes + 'A' - 1;
2275                 else
2276                         line[0] = bytes - 26 + 'a' - 1;
2277                 encode_85(line + 1, cp, bytes);
2278                 cp = (char *) cp + bytes;
2279                 fprintf(file, "%s", prefix);
2280                 fputs(line, file);
2281                 fputc('\n', file);
2282         }
2283         fprintf(file, "%s\n", prefix);
2284         free(data);
2285 }
2286
2287 static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two,
2288                              const char *prefix)
2289 {
2290         fprintf(file, "%sGIT binary patch\n", prefix);
2291         emit_binary_diff_body(file, one, two, prefix);
2292         emit_binary_diff_body(file, two, one, prefix);
2293 }
2294
2295 int diff_filespec_is_binary(struct diff_filespec *one)
2296 {
2297         if (one->is_binary == -1) {
2298                 diff_filespec_load_driver(one);
2299                 if (one->driver->binary != -1)
2300                         one->is_binary = one->driver->binary;
2301                 else {
2302                         if (!one->data && DIFF_FILE_VALID(one))
2303                                 diff_populate_filespec(one, CHECK_BINARY);
2304                         if (one->is_binary == -1 && one->data)
2305                                 one->is_binary = buffer_is_binary(one->data,
2306                                                 one->size);
2307                         if (one->is_binary == -1)
2308                                 one->is_binary = 0;
2309                 }
2310         }
2311         return one->is_binary;
2312 }
2313
2314 static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
2315 {
2316         diff_filespec_load_driver(one);
2317         return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
2318 }
2319
2320 void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
2321 {
2322         if (!options->a_prefix)
2323                 options->a_prefix = a;
2324         if (!options->b_prefix)
2325                 options->b_prefix = b;
2326 }
2327
2328 struct userdiff_driver *get_textconv(struct diff_filespec *one)
2329 {
2330         if (!DIFF_FILE_VALID(one))
2331                 return NULL;
2332
2333         diff_filespec_load_driver(one);
2334         return userdiff_get_textconv(one->driver);
2335 }
2336
2337 static void builtin_diff(const char *name_a,
2338                          const char *name_b,
2339                          struct diff_filespec *one,
2340                          struct diff_filespec *two,
2341                          const char *xfrm_msg,
2342                          int must_show_header,
2343                          struct diff_options *o,
2344                          int complete_rewrite)
2345 {
2346         mmfile_t mf1, mf2;
2347         const char *lbl[2];
2348         char *a_one, *b_two;
2349         const char *meta = diff_get_color_opt(o, DIFF_METAINFO);
2350         const char *reset = diff_get_color_opt(o, DIFF_RESET);
2351         const char *a_prefix, *b_prefix;
2352         struct userdiff_driver *textconv_one = NULL;
2353         struct userdiff_driver *textconv_two = NULL;
2354         struct strbuf header = STRBUF_INIT;
2355         const char *line_prefix = diff_line_prefix(o);
2356
2357         diff_set_mnemonic_prefix(o, "a/", "b/");
2358         if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
2359                 a_prefix = o->b_prefix;
2360                 b_prefix = o->a_prefix;
2361         } else {
2362                 a_prefix = o->a_prefix;
2363                 b_prefix = o->b_prefix;
2364         }
2365
2366         if (o->submodule_format == DIFF_SUBMODULE_LOG &&
2367             (!one->mode || S_ISGITLINK(one->mode)) &&
2368             (!two->mode || S_ISGITLINK(two->mode))) {
2369                 const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
2370                 const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
2371                 show_submodule_summary(o->file, one->path ? one->path : two->path,
2372                                 line_prefix,
2373                                 &one->oid, &two->oid,
2374                                 two->dirty_submodule,
2375                                 meta, del, add, reset);
2376                 return;
2377         } else if (o->submodule_format == DIFF_SUBMODULE_INLINE_DIFF &&
2378                    (!one->mode || S_ISGITLINK(one->mode)) &&
2379                    (!two->mode || S_ISGITLINK(two->mode))) {
2380                 const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
2381                 const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
2382                 show_submodule_inline_diff(o->file, one->path ? one->path : two->path,
2383                                 line_prefix,
2384                                 &one->oid, &two->oid,
2385                                 two->dirty_submodule,
2386                                 meta, del, add, reset, o);
2387                 return;
2388         }
2389
2390         if (DIFF_OPT_TST(o, ALLOW_TEXTCONV)) {
2391                 textconv_one = get_textconv(one);
2392                 textconv_two = get_textconv(two);
2393         }
2394
2395         /* Never use a non-valid filename anywhere if at all possible */
2396         name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
2397         name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
2398
2399         a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
2400         b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
2401         lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
2402         lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
2403         strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, meta, a_one, b_two, reset);
2404         if (lbl[0][0] == '/') {
2405                 /* /dev/null */
2406                 strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, meta, two->mode, reset);
2407                 if (xfrm_msg)
2408                         strbuf_addstr(&header, xfrm_msg);
2409                 must_show_header = 1;
2410         }
2411         else if (lbl[1][0] == '/') {
2412                 strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, meta, one->mode, reset);
2413                 if (xfrm_msg)
2414                         strbuf_addstr(&header, xfrm_msg);
2415                 must_show_header = 1;
2416         }
2417         else {
2418                 if (one->mode != two->mode) {
2419                         strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, meta, one->mode, reset);
2420                         strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, meta, two->mode, reset);
2421                         must_show_header = 1;
2422                 }
2423                 if (xfrm_msg)
2424                         strbuf_addstr(&header, xfrm_msg);
2425
2426                 /*
2427                  * we do not run diff between different kind
2428                  * of objects.
2429                  */
2430                 if ((one->mode ^ two->mode) & S_IFMT)
2431                         goto free_ab_and_return;
2432                 if (complete_rewrite &&
2433                     (textconv_one || !diff_filespec_is_binary(one)) &&
2434                     (textconv_two || !diff_filespec_is_binary(two))) {
2435                         fprintf(o->file, "%s", header.buf);
2436                         strbuf_reset(&header);
2437                         emit_rewrite_diff(name_a, name_b, one, two,
2438                                                 textconv_one, textconv_two, o);
2439                         o->found_changes = 1;
2440                         goto free_ab_and_return;
2441                 }
2442         }
2443
2444         if (o->irreversible_delete && lbl[1][0] == '/') {
2445                 fprintf(o->file, "%s", header.buf);
2446                 strbuf_reset(&header);
2447                 goto free_ab_and_return;
2448         } else if (!DIFF_OPT_TST(o, TEXT) &&
2449             ( (!textconv_one && diff_filespec_is_binary(one)) ||
2450               (!textconv_two && diff_filespec_is_binary(two)) )) {
2451                 if (!one->data && !two->data &&
2452                     S_ISREG(one->mode) && S_ISREG(two->mode) &&
2453                     !DIFF_OPT_TST(o, BINARY)) {
2454                         if (!oidcmp(&one->oid, &two->oid)) {
2455                                 if (must_show_header)
2456                                         fprintf(o->file, "%s", header.buf);
2457                                 goto free_ab_and_return;
2458                         }
2459                         fprintf(o->file, "%s", header.buf);
2460                         fprintf(o->file, "%sBinary files %s and %s differ\n",
2461                                 line_prefix, lbl[0], lbl[1]);
2462                         goto free_ab_and_return;
2463                 }
2464                 if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2465                         die("unable to read files to diff");
2466                 /* Quite common confusing case */
2467                 if (mf1.size == mf2.size &&
2468                     !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
2469                         if (must_show_header)
2470                                 fprintf(o->file, "%s", header.buf);
2471                         goto free_ab_and_return;
2472                 }
2473                 fprintf(o->file, "%s", header.buf);
2474                 strbuf_reset(&header);
2475                 if (DIFF_OPT_TST(o, BINARY))
2476                         emit_binary_diff(o->file, &mf1, &mf2, line_prefix);
2477                 else
2478                         fprintf(o->file, "%sBinary files %s and %s differ\n",
2479                                 line_prefix, lbl[0], lbl[1]);
2480                 o->found_changes = 1;
2481         } else {
2482                 /* Crazy xdl interfaces.. */
2483                 const char *diffopts = getenv("GIT_DIFF_OPTS");
2484                 const char *v;
2485                 xpparam_t xpp;
2486                 xdemitconf_t xecfg;
2487                 struct emit_callback ecbdata;
2488                 const struct userdiff_funcname *pe;
2489
2490                 if (must_show_header) {
2491                         fprintf(o->file, "%s", header.buf);
2492                         strbuf_reset(&header);
2493                 }
2494
2495                 mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
2496                 mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
2497
2498                 pe = diff_funcname_pattern(one);
2499                 if (!pe)
2500                         pe = diff_funcname_pattern(two);
2501
2502                 memset(&xpp, 0, sizeof(xpp));
2503                 memset(&xecfg, 0, sizeof(xecfg));
2504                 memset(&ecbdata, 0, sizeof(ecbdata));
2505                 ecbdata.label_path = lbl;
2506                 ecbdata.color_diff = want_color(o->use_color);
2507                 ecbdata.ws_rule = whitespace_rule(name_b);
2508                 if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
2509                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
2510                 ecbdata.opt = o;
2511                 ecbdata.header = header.len ? &header : NULL;
2512                 xpp.flags = o->xdl_opts;
2513                 xecfg.ctxlen = o->context;
2514                 xecfg.interhunkctxlen = o->interhunkcontext;
2515                 xecfg.flags = XDL_EMIT_FUNCNAMES;
2516                 if (DIFF_OPT_TST(o, FUNCCONTEXT))
2517                         xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
2518                 if (pe)
2519                         xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
2520                 if (!diffopts)
2521                         ;
2522                 else if (skip_prefix(diffopts, "--unified=", &v))
2523                         xecfg.ctxlen = strtoul(v, NULL, 10);
2524                 else if (skip_prefix(diffopts, "-u", &v))
2525                         xecfg.ctxlen = strtoul(v, NULL, 10);
2526                 if (o->word_diff)
2527                         init_diff_words_data(&ecbdata, o, one, two);
2528                 if (xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
2529                                   &xpp, &xecfg))
2530                         die("unable to generate diff for %s", one->path);
2531                 if (o->word_diff)
2532                         free_diff_words_data(&ecbdata);
2533                 if (textconv_one)
2534                         free(mf1.ptr);
2535                 if (textconv_two)
2536                         free(mf2.ptr);
2537                 xdiff_clear_find_func(&xecfg);
2538         }
2539
2540  free_ab_and_return:
2541         strbuf_release(&header);
2542         diff_free_filespec_data(one);
2543         diff_free_filespec_data(two);
2544         free(a_one);
2545         free(b_two);
2546         return;
2547 }
2548
2549 static void builtin_diffstat(const char *name_a, const char *name_b,
2550                              struct diff_filespec *one,
2551                              struct diff_filespec *two,
2552                              struct diffstat_t *diffstat,
2553                              struct diff_options *o,
2554                              struct diff_filepair *p)
2555 {
2556         mmfile_t mf1, mf2;
2557         struct diffstat_file *data;
2558         int same_contents;
2559         int complete_rewrite = 0;
2560
2561         if (!DIFF_PAIR_UNMERGED(p)) {
2562                 if (p->status == DIFF_STATUS_MODIFIED && p->score)
2563                         complete_rewrite = 1;
2564         }
2565
2566         data = diffstat_add(diffstat, name_a, name_b);
2567         data->is_interesting = p->status != DIFF_STATUS_UNKNOWN;
2568
2569         if (!one || !two) {
2570                 data->is_unmerged = 1;
2571                 return;
2572         }
2573
2574         same_contents = !oidcmp(&one->oid, &two->oid);
2575
2576         if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
2577                 data->is_binary = 1;
2578                 if (same_contents) {
2579                         data->added = 0;
2580                         data->deleted = 0;
2581                 } else {
2582                         data->added = diff_filespec_size(two);
2583                         data->deleted = diff_filespec_size(one);
2584                 }
2585         }
2586
2587         else if (complete_rewrite) {
2588                 diff_populate_filespec(one, 0);
2589                 diff_populate_filespec(two, 0);
2590                 data->deleted = count_lines(one->data, one->size);
2591                 data->added = count_lines(two->data, two->size);
2592         }
2593
2594         else if (!same_contents) {
2595                 /* Crazy xdl interfaces.. */
2596                 xpparam_t xpp;
2597                 xdemitconf_t xecfg;
2598
2599                 if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2600                         die("unable to read files to diff");
2601
2602                 memset(&xpp, 0, sizeof(xpp));
2603                 memset(&xecfg, 0, sizeof(xecfg));
2604                 xpp.flags = o->xdl_opts;
2605                 xecfg.ctxlen = o->context;
2606                 xecfg.interhunkctxlen = o->interhunkcontext;
2607                 if (xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
2608                                   &xpp, &xecfg))
2609                         die("unable to generate diffstat for %s", one->path);
2610         }
2611
2612         diff_free_filespec_data(one);
2613         diff_free_filespec_data(two);
2614 }
2615
2616 static void builtin_checkdiff(const char *name_a, const char *name_b,
2617                               const char *attr_path,
2618                               struct diff_filespec *one,
2619                               struct diff_filespec *two,
2620                               struct diff_options *o)
2621 {
2622         mmfile_t mf1, mf2;
2623         struct checkdiff_t data;
2624
2625         if (!two)
2626                 return;
2627
2628         memset(&data, 0, sizeof(data));
2629         data.filename = name_b ? name_b : name_a;
2630         data.lineno = 0;
2631         data.o = o;
2632         data.ws_rule = whitespace_rule(attr_path);
2633         data.conflict_marker_size = ll_merge_marker_size(attr_path);
2634
2635         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2636                 die("unable to read files to diff");
2637
2638         /*
2639          * All the other codepaths check both sides, but not checking
2640          * the "old" side here is deliberate.  We are checking the newly
2641          * introduced changes, and as long as the "new" side is text, we
2642          * can and should check what it introduces.
2643          */
2644         if (diff_filespec_is_binary(two))
2645                 goto free_and_return;
2646         else {
2647                 /* Crazy xdl interfaces.. */
2648                 xpparam_t xpp;
2649                 xdemitconf_t xecfg;
2650
2651                 memset(&xpp, 0, sizeof(xpp));
2652                 memset(&xecfg, 0, sizeof(xecfg));
2653                 xecfg.ctxlen = 1; /* at least one context line */
2654                 xpp.flags = 0;
2655                 if (xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
2656                                   &xpp, &xecfg))
2657                         die("unable to generate checkdiff for %s", one->path);
2658
2659                 if (data.ws_rule & WS_BLANK_AT_EOF) {
2660                         struct emit_callback ecbdata;
2661                         int blank_at_eof;
2662
2663                         ecbdata.ws_rule = data.ws_rule;
2664                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
2665                         blank_at_eof = ecbdata.blank_at_eof_in_postimage;
2666
2667                         if (blank_at_eof) {
2668                                 static char *err;
2669                                 if (!err)
2670                                         err = whitespace_error_string(WS_BLANK_AT_EOF);
2671                                 fprintf(o->file, "%s:%d: %s.\n",
2672                                         data.filename, blank_at_eof, err);
2673                                 data.status = 1; /* report errors */
2674                         }
2675                 }
2676         }
2677  free_and_return:
2678         diff_free_filespec_data(one);
2679         diff_free_filespec_data(two);
2680         if (data.status)
2681                 DIFF_OPT_SET(o, CHECK_FAILED);
2682 }
2683
2684 struct diff_filespec *alloc_filespec(const char *path)
2685 {
2686         struct diff_filespec *spec;
2687
2688         FLEXPTR_ALLOC_STR(spec, path, path);
2689         spec->count = 1;
2690         spec->is_binary = -1;
2691         return spec;
2692 }
2693
2694 void free_filespec(struct diff_filespec *spec)
2695 {
2696         if (!--spec->count) {
2697                 diff_free_filespec_data(spec);
2698                 free(spec);
2699         }
2700 }
2701
2702 void fill_filespec(struct diff_filespec *spec, const struct object_id *oid,
2703                    int oid_valid, unsigned short mode)
2704 {
2705         if (mode) {
2706                 spec->mode = canon_mode(mode);
2707                 oidcpy(&spec->oid, oid);
2708                 spec->oid_valid = oid_valid;
2709         }
2710 }
2711
2712 /*
2713  * Given a name and sha1 pair, if the index tells us the file in
2714  * the work tree has that object contents, return true, so that
2715  * prepare_temp_file() does not have to inflate and extract.
2716  */
2717 static int reuse_worktree_file(const char *name, const struct object_id *oid, int want_file)
2718 {
2719         const struct cache_entry *ce;
2720         struct stat st;
2721         int pos, len;
2722
2723         /*
2724          * We do not read the cache ourselves here, because the
2725          * benchmark with my previous version that always reads cache
2726          * shows that it makes things worse for diff-tree comparing
2727          * two linux-2.6 kernel trees in an already checked out work
2728          * tree.  This is because most diff-tree comparisons deal with
2729          * only a small number of files, while reading the cache is
2730          * expensive for a large project, and its cost outweighs the
2731          * savings we get by not inflating the object to a temporary
2732          * file.  Practically, this code only helps when we are used
2733          * by diff-cache --cached, which does read the cache before
2734          * calling us.
2735          */
2736         if (!active_cache)
2737                 return 0;
2738
2739         /* We want to avoid the working directory if our caller
2740          * doesn't need the data in a normal file, this system
2741          * is rather slow with its stat/open/mmap/close syscalls,
2742          * and the object is contained in a pack file.  The pack
2743          * is probably already open and will be faster to obtain
2744          * the data through than the working directory.  Loose
2745          * objects however would tend to be slower as they need
2746          * to be individually opened and inflated.
2747          */
2748         if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(oid->hash))
2749                 return 0;
2750
2751         /*
2752          * Similarly, if we'd have to convert the file contents anyway, that
2753          * makes the optimization not worthwhile.
2754          */
2755         if (!want_file && would_convert_to_git(&the_index, name))
2756                 return 0;
2757
2758         len = strlen(name);
2759         pos = cache_name_pos(name, len);
2760         if (pos < 0)
2761                 return 0;
2762         ce = active_cache[pos];
2763
2764         /*
2765          * This is not the sha1 we are looking for, or
2766          * unreusable because it is not a regular file.
2767          */
2768         if (oidcmp(oid, &ce->oid) || !S_ISREG(ce->ce_mode))
2769                 return 0;
2770
2771         /*
2772          * If ce is marked as "assume unchanged", there is no
2773          * guarantee that work tree matches what we are looking for.
2774          */
2775         if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
2776                 return 0;
2777
2778         /*
2779          * If ce matches the file in the work tree, we can reuse it.
2780          */
2781         if (ce_uptodate(ce) ||
2782             (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
2783                 return 1;
2784
2785         return 0;
2786 }
2787
2788 static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
2789 {
2790         struct strbuf buf = STRBUF_INIT;
2791         char *dirty = "";
2792
2793         /* Are we looking at the work tree? */
2794         if (s->dirty_submodule)
2795                 dirty = "-dirty";
2796
2797         strbuf_addf(&buf, "Subproject commit %s%s\n",
2798                     oid_to_hex(&s->oid), dirty);
2799         s->size = buf.len;
2800         if (size_only) {
2801                 s->data = NULL;
2802                 strbuf_release(&buf);
2803         } else {
2804                 s->data = strbuf_detach(&buf, NULL);
2805                 s->should_free = 1;
2806         }
2807         return 0;
2808 }
2809
2810 /*
2811  * While doing rename detection and pickaxe operation, we may need to
2812  * grab the data for the blob (or file) for our own in-core comparison.
2813  * diff_filespec has data and size fields for this purpose.
2814  */
2815 int diff_populate_filespec(struct diff_filespec *s, unsigned int flags)
2816 {
2817         int size_only = flags & CHECK_SIZE_ONLY;
2818         int err = 0;
2819         /*
2820          * demote FAIL to WARN to allow inspecting the situation
2821          * instead of refusing.
2822          */
2823         enum safe_crlf crlf_warn = (safe_crlf == SAFE_CRLF_FAIL
2824                                     ? SAFE_CRLF_WARN
2825                                     : safe_crlf);
2826
2827         if (!DIFF_FILE_VALID(s))
2828                 die("internal error: asking to populate invalid file.");
2829         if (S_ISDIR(s->mode))
2830                 return -1;
2831
2832         if (s->data)
2833                 return 0;
2834
2835         if (size_only && 0 < s->size)
2836                 return 0;
2837
2838         if (S_ISGITLINK(s->mode))
2839                 return diff_populate_gitlink(s, size_only);
2840
2841         if (!s->oid_valid ||
2842             reuse_worktree_file(s->path, &s->oid, 0)) {
2843                 struct strbuf buf = STRBUF_INIT;
2844                 struct stat st;
2845                 int fd;
2846
2847                 if (lstat(s->path, &st) < 0) {
2848                         if (errno == ENOENT) {
2849                         err_empty:
2850                                 err = -1;
2851                         empty:
2852                                 s->data = (char *)"";
2853                                 s->size = 0;
2854                                 return err;
2855                         }
2856                 }
2857                 s->size = xsize_t(st.st_size);
2858                 if (!s->size)
2859                         goto empty;
2860                 if (S_ISLNK(st.st_mode)) {
2861                         struct strbuf sb = STRBUF_INIT;
2862
2863                         if (strbuf_readlink(&sb, s->path, s->size))
2864                                 goto err_empty;
2865                         s->size = sb.len;
2866                         s->data = strbuf_detach(&sb, NULL);
2867                         s->should_free = 1;
2868                         return 0;
2869                 }
2870
2871                 /*
2872                  * Even if the caller would be happy with getting
2873                  * only the size, we cannot return early at this
2874                  * point if the path requires us to run the content
2875                  * conversion.
2876                  */
2877                 if (size_only && !would_convert_to_git(&the_index, s->path))
2878                         return 0;
2879
2880                 /*
2881                  * Note: this check uses xsize_t(st.st_size) that may
2882                  * not be the true size of the blob after it goes
2883                  * through convert_to_git().  This may not strictly be
2884                  * correct, but the whole point of big_file_threshold
2885                  * and is_binary check being that we want to avoid
2886                  * opening the file and inspecting the contents, this
2887                  * is probably fine.
2888                  */
2889                 if ((flags & CHECK_BINARY) &&
2890                     s->size > big_file_threshold && s->is_binary == -1) {
2891                         s->is_binary = 1;
2892                         return 0;
2893                 }
2894                 fd = open(s->path, O_RDONLY);
2895                 if (fd < 0)
2896                         goto err_empty;
2897                 s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
2898                 close(fd);
2899                 s->should_munmap = 1;
2900
2901                 /*
2902                  * Convert from working tree format to canonical git format
2903                  */
2904                 if (convert_to_git(&the_index, s->path, s->data, s->size, &buf, crlf_warn)) {
2905                         size_t size = 0;
2906                         munmap(s->data, s->size);
2907                         s->should_munmap = 0;
2908                         s->data = strbuf_detach(&buf, &size);
2909                         s->size = size;
2910                         s->should_free = 1;
2911                 }
2912         }
2913         else {
2914                 enum object_type type;
2915                 if (size_only || (flags & CHECK_BINARY)) {
2916                         type = sha1_object_info(s->oid.hash, &s->size);
2917                         if (type < 0)
2918                                 die("unable to read %s",
2919                                     oid_to_hex(&s->oid));
2920                         if (size_only)
2921                                 return 0;
2922                         if (s->size > big_file_threshold && s->is_binary == -1) {
2923                                 s->is_binary = 1;
2924                                 return 0;
2925                         }
2926                 }
2927                 s->data = read_sha1_file(s->oid.hash, &type, &s->size);
2928                 if (!s->data)
2929                         die("unable to read %s", oid_to_hex(&s->oid));
2930                 s->should_free = 1;
2931         }
2932         return 0;
2933 }
2934
2935 void diff_free_filespec_blob(struct diff_filespec *s)
2936 {
2937         if (s->should_free)
2938                 free(s->data);
2939         else if (s->should_munmap)
2940                 munmap(s->data, s->size);
2941
2942         if (s->should_free || s->should_munmap) {
2943                 s->should_free = s->should_munmap = 0;
2944                 s->data = NULL;
2945         }
2946 }
2947
2948 void diff_free_filespec_data(struct diff_filespec *s)
2949 {
2950         diff_free_filespec_blob(s);
2951         FREE_AND_NULL(s->cnt_data);
2952 }
2953
2954 static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
2955                            void *blob,
2956                            unsigned long size,
2957                            const struct object_id *oid,
2958                            int mode)
2959 {
2960         int fd;
2961         struct strbuf buf = STRBUF_INIT;
2962         struct strbuf template = STRBUF_INIT;
2963         char *path_dup = xstrdup(path);
2964         const char *base = basename(path_dup);
2965
2966         /* Generate "XXXXXX_basename.ext" */
2967         strbuf_addstr(&template, "XXXXXX_");
2968         strbuf_addstr(&template, base);
2969
2970         fd = mks_tempfile_ts(&temp->tempfile, template.buf, strlen(base) + 1);
2971         if (fd < 0)
2972                 die_errno("unable to create temp-file");
2973         if (convert_to_working_tree(path,
2974                         (const char *)blob, (size_t)size, &buf)) {
2975                 blob = buf.buf;
2976                 size = buf.len;
2977         }
2978         if (write_in_full(fd, blob, size) != size)
2979                 die_errno("unable to write temp-file");
2980         close_tempfile(&temp->tempfile);
2981         temp->name = get_tempfile_path(&temp->tempfile);
2982         oid_to_hex_r(temp->hex, oid);
2983         xsnprintf(temp->mode, sizeof(temp->mode), "%06o", mode);
2984         strbuf_release(&buf);
2985         strbuf_release(&template);
2986         free(path_dup);
2987 }
2988
2989 static struct diff_tempfile *prepare_temp_file(const char *name,
2990                 struct diff_filespec *one)
2991 {
2992         struct diff_tempfile *temp = claim_diff_tempfile();
2993
2994         if (!DIFF_FILE_VALID(one)) {
2995         not_a_valid_file:
2996                 /* A '-' entry produces this for file-2, and
2997                  * a '+' entry produces this for file-1.
2998                  */
2999                 temp->name = "/dev/null";
3000                 xsnprintf(temp->hex, sizeof(temp->hex), ".");
3001                 xsnprintf(temp->mode, sizeof(temp->mode), ".");
3002                 return temp;
3003         }
3004
3005         if (!S_ISGITLINK(one->mode) &&
3006             (!one->oid_valid ||
3007              reuse_worktree_file(name, &one->oid, 1))) {
3008                 struct stat st;
3009                 if (lstat(name, &st) < 0) {
3010                         if (errno == ENOENT)
3011                                 goto not_a_valid_file;
3012                         die_errno("stat(%s)", name);
3013                 }
3014                 if (S_ISLNK(st.st_mode)) {
3015                         struct strbuf sb = STRBUF_INIT;
3016                         if (strbuf_readlink(&sb, name, st.st_size) < 0)
3017                                 die_errno("readlink(%s)", name);
3018                         prep_temp_blob(name, temp, sb.buf, sb.len,
3019                                        (one->oid_valid ?
3020                                         &one->oid : &null_oid),
3021                                        (one->oid_valid ?
3022                                         one->mode : S_IFLNK));
3023                         strbuf_release(&sb);
3024                 }
3025                 else {
3026                         /* we can borrow from the file in the work tree */
3027                         temp->name = name;
3028                         if (!one->oid_valid)
3029                                 oid_to_hex_r(temp->hex, &null_oid);
3030                         else
3031                                 oid_to_hex_r(temp->hex, &one->oid);
3032                         /* Even though we may sometimes borrow the
3033                          * contents from the work tree, we always want
3034                          * one->mode.  mode is trustworthy even when
3035                          * !(one->oid_valid), as long as
3036                          * DIFF_FILE_VALID(one).
3037                          */
3038                         xsnprintf(temp->mode, sizeof(temp->mode), "%06o", one->mode);
3039                 }
3040                 return temp;
3041         }
3042         else {
3043                 if (diff_populate_filespec(one, 0))
3044                         die("cannot read data blob for %s", one->path);
3045                 prep_temp_blob(name, temp, one->data, one->size,
3046                                &one->oid, one->mode);
3047         }
3048         return temp;
3049 }
3050
3051 static void add_external_diff_name(struct argv_array *argv,
3052                                    const char *name,
3053                                    struct diff_filespec *df)
3054 {
3055         struct diff_tempfile *temp = prepare_temp_file(name, df);
3056         argv_array_push(argv, temp->name);
3057         argv_array_push(argv, temp->hex);
3058         argv_array_push(argv, temp->mode);
3059 }
3060
3061 /* An external diff command takes:
3062  *
3063  * diff-cmd name infile1 infile1-sha1 infile1-mode \
3064  *               infile2 infile2-sha1 infile2-mode [ rename-to ]
3065  *
3066  */
3067 static void run_external_diff(const char *pgm,
3068                               const char *name,
3069                               const char *other,
3070                               struct diff_filespec *one,
3071                               struct diff_filespec *two,
3072                               const char *xfrm_msg,
3073                               int complete_rewrite,
3074                               struct diff_options *o)
3075 {
3076         struct argv_array argv = ARGV_ARRAY_INIT;
3077         struct argv_array env = ARGV_ARRAY_INIT;
3078         struct diff_queue_struct *q = &diff_queued_diff;
3079
3080         argv_array_push(&argv, pgm);
3081         argv_array_push(&argv, name);
3082
3083         if (one && two) {
3084                 add_external_diff_name(&argv, name, one);
3085                 if (!other)
3086                         add_external_diff_name(&argv, name, two);
3087                 else {
3088                         add_external_diff_name(&argv, other, two);
3089                         argv_array_push(&argv, other);
3090                         argv_array_push(&argv, xfrm_msg);
3091                 }
3092         }
3093
3094         argv_array_pushf(&env, "GIT_DIFF_PATH_COUNTER=%d", ++o->diff_path_counter);
3095         argv_array_pushf(&env, "GIT_DIFF_PATH_TOTAL=%d", q->nr);
3096
3097         if (run_command_v_opt_cd_env(argv.argv, RUN_USING_SHELL, NULL, env.argv))
3098                 die(_("external diff died, stopping at %s"), name);
3099
3100         remove_tempfile();
3101         argv_array_clear(&argv);
3102         argv_array_clear(&env);
3103 }
3104
3105 static int similarity_index(struct diff_filepair *p)
3106 {
3107         return p->score * 100 / MAX_SCORE;
3108 }
3109
3110 static const char *diff_abbrev_oid(const struct object_id *oid, int abbrev)
3111 {
3112         if (startup_info->have_repository)
3113                 return find_unique_abbrev(oid->hash, abbrev);
3114         else {
3115                 char *hex = oid_to_hex(oid);
3116                 if (abbrev < 0)
3117                         abbrev = FALLBACK_DEFAULT_ABBREV;
3118                 if (abbrev > GIT_SHA1_HEXSZ)
3119                         die("BUG: oid abbreviation out of range: %d", abbrev);
3120                 if (abbrev)
3121                         hex[abbrev] = '\0';
3122                 return hex;
3123         }
3124 }
3125
3126 static void fill_metainfo(struct strbuf *msg,
3127                           const char *name,
3128                           const char *other,
3129                           struct diff_filespec *one,
3130                           struct diff_filespec *two,
3131                           struct diff_options *o,
3132                           struct diff_filepair *p,
3133                           int *must_show_header,
3134                           int use_color)
3135 {
3136         const char *set = diff_get_color(use_color, DIFF_METAINFO);
3137         const char *reset = diff_get_color(use_color, DIFF_RESET);
3138         const char *line_prefix = diff_line_prefix(o);
3139
3140         *must_show_header = 1;
3141         strbuf_init(msg, PATH_MAX * 2 + 300);
3142         switch (p->status) {
3143         case DIFF_STATUS_COPIED:
3144                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
3145                             line_prefix, set, similarity_index(p));
3146                 strbuf_addf(msg, "%s\n%s%scopy from ",
3147                             reset,  line_prefix, set);
3148                 quote_c_style(name, msg, NULL, 0);
3149                 strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
3150                 quote_c_style(other, msg, NULL, 0);
3151                 strbuf_addf(msg, "%s\n", reset);
3152                 break;
3153         case DIFF_STATUS_RENAMED:
3154                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
3155                             line_prefix, set, similarity_index(p));
3156                 strbuf_addf(msg, "%s\n%s%srename from ",
3157                             reset, line_prefix, set);
3158                 quote_c_style(name, msg, NULL, 0);
3159                 strbuf_addf(msg, "%s\n%s%srename to ",
3160                             reset, line_prefix, set);
3161                 quote_c_style(other, msg, NULL, 0);
3162                 strbuf_addf(msg, "%s\n", reset);
3163                 break;
3164         case DIFF_STATUS_MODIFIED:
3165                 if (p->score) {
3166                         strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
3167                                     line_prefix,
3168                                     set, similarity_index(p), reset);
3169                         break;
3170                 }
3171                 /* fallthru */
3172         default:
3173                 *must_show_header = 0;
3174         }
3175         if (one && two && oidcmp(&one->oid, &two->oid)) {
3176                 int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
3177
3178                 if (DIFF_OPT_TST(o, BINARY)) {
3179                         mmfile_t mf;
3180                         if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
3181                             (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
3182                                 abbrev = 40;
3183                 }
3184                 strbuf_addf(msg, "%s%sindex %s..%s", line_prefix, set,
3185                             diff_abbrev_oid(&one->oid, abbrev),
3186                             diff_abbrev_oid(&two->oid, abbrev));
3187                 if (one->mode == two->mode)
3188                         strbuf_addf(msg, " %06o", one->mode);
3189                 strbuf_addf(msg, "%s\n", reset);
3190         }
3191 }
3192
3193 static void run_diff_cmd(const char *pgm,
3194                          const char *name,
3195                          const char *other,
3196                          const char *attr_path,
3197                          struct diff_filespec *one,
3198                          struct diff_filespec *two,
3199                          struct strbuf *msg,
3200                          struct diff_options *o,
3201                          struct diff_filepair *p)
3202 {
3203         const char *xfrm_msg = NULL;
3204         int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
3205         int must_show_header = 0;
3206
3207
3208         if (DIFF_OPT_TST(o, ALLOW_EXTERNAL)) {
3209                 struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
3210                 if (drv && drv->external)
3211                         pgm = drv->external;
3212         }
3213
3214         if (msg) {
3215                 /*
3216                  * don't use colors when the header is intended for an
3217                  * external diff driver
3218                  */
3219                 fill_metainfo(msg, name, other, one, two, o, p,
3220                               &must_show_header,
3221                               want_color(o->use_color) && !pgm);
3222                 xfrm_msg = msg->len ? msg->buf : NULL;
3223         }
3224
3225         if (pgm) {
3226                 run_external_diff(pgm, name, other, one, two, xfrm_msg,
3227                                   complete_rewrite, o);
3228                 return;
3229         }
3230         if (one && two)
3231                 builtin_diff(name, other ? other : name,
3232                              one, two, xfrm_msg, must_show_header,
3233                              o, complete_rewrite);
3234         else
3235                 fprintf(o->file, "* Unmerged path %s\n", name);
3236 }
3237
3238 static void diff_fill_oid_info(struct diff_filespec *one)
3239 {
3240         if (DIFF_FILE_VALID(one)) {
3241                 if (!one->oid_valid) {
3242                         struct stat st;
3243                         if (one->is_stdin) {
3244                                 oidclr(&one->oid);
3245                                 return;
3246                         }
3247                         if (lstat(one->path, &st) < 0)
3248                                 die_errno("stat '%s'", one->path);
3249                         if (index_path(one->oid.hash, one->path, &st, 0))
3250                                 die("cannot hash %s", one->path);
3251                 }
3252         }
3253         else
3254                 oidclr(&one->oid);
3255 }
3256
3257 static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
3258 {
3259         /* Strip the prefix but do not molest /dev/null and absolute paths */
3260         if (*namep && **namep != '/') {
3261                 *namep += prefix_length;
3262                 if (**namep == '/')
3263                         ++*namep;
3264         }
3265         if (*otherp && **otherp != '/') {
3266                 *otherp += prefix_length;
3267                 if (**otherp == '/')
3268                         ++*otherp;
3269         }
3270 }
3271
3272 static void run_diff(struct diff_filepair *p, struct diff_options *o)
3273 {
3274         const char *pgm = external_diff();
3275         struct strbuf msg;
3276         struct diff_filespec *one = p->one;
3277         struct diff_filespec *two = p->two;
3278         const char *name;
3279         const char *other;
3280         const char *attr_path;
3281
3282         name  = p->one->path;
3283         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3284         attr_path = name;
3285         if (o->prefix_length)
3286                 strip_prefix(o->prefix_length, &name, &other);
3287
3288         if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
3289                 pgm = NULL;
3290
3291         if (DIFF_PAIR_UNMERGED(p)) {
3292                 run_diff_cmd(pgm, name, NULL, attr_path,
3293                              NULL, NULL, NULL, o, p);
3294                 return;
3295         }
3296
3297         diff_fill_oid_info(one);
3298         diff_fill_oid_info(two);
3299
3300         if (!pgm &&
3301             DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
3302             (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
3303                 /*
3304                  * a filepair that changes between file and symlink
3305                  * needs to be split into deletion and creation.
3306                  */
3307                 struct diff_filespec *null = alloc_filespec(two->path);
3308                 run_diff_cmd(NULL, name, other, attr_path,
3309                              one, null, &msg, o, p);
3310                 free(null);
3311                 strbuf_release(&msg);
3312
3313                 null = alloc_filespec(one->path);
3314                 run_diff_cmd(NULL, name, other, attr_path,
3315                              null, two, &msg, o, p);
3316                 free(null);
3317         }
3318         else
3319                 run_diff_cmd(pgm, name, other, attr_path,
3320                              one, two, &msg, o, p);
3321
3322         strbuf_release(&msg);
3323 }
3324
3325 static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
3326                          struct diffstat_t *diffstat)
3327 {
3328         const char *name;
3329         const char *other;
3330
3331         if (DIFF_PAIR_UNMERGED(p)) {
3332                 /* unmerged */
3333                 builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, p);
3334                 return;
3335         }
3336
3337         name = p->one->path;
3338         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3339
3340         if (o->prefix_length)
3341                 strip_prefix(o->prefix_length, &name, &other);
3342
3343         diff_fill_oid_info(p->one);
3344         diff_fill_oid_info(p->two);
3345
3346         builtin_diffstat(name, other, p->one, p->two, diffstat, o, p);
3347 }
3348
3349 static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
3350 {
3351         const char *name;
3352         const char *other;
3353         const char *attr_path;
3354
3355         if (DIFF_PAIR_UNMERGED(p)) {
3356                 /* unmerged */
3357                 return;
3358         }
3359
3360         name = p->one->path;
3361         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3362         attr_path = other ? other : name;
3363
3364         if (o->prefix_length)
3365                 strip_prefix(o->prefix_length, &name, &other);
3366
3367         diff_fill_oid_info(p->one);
3368         diff_fill_oid_info(p->two);
3369
3370         builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
3371 }
3372
3373 void diff_setup(struct diff_options *options)
3374 {
3375         memcpy(options, &default_diff_options, sizeof(*options));
3376
3377         options->file = stdout;
3378
3379         options->abbrev = DEFAULT_ABBREV;
3380         options->line_termination = '\n';
3381         options->break_opt = -1;
3382         options->rename_limit = -1;
3383         options->dirstat_permille = diff_dirstat_permille_default;
3384         options->context = diff_context_default;
3385         options->interhunkcontext = diff_interhunk_context_default;
3386         options->ws_error_highlight = ws_error_highlight_default;
3387         DIFF_OPT_SET(options, RENAME_EMPTY);
3388
3389         /* pathchange left =NULL by default */
3390         options->change = diff_change;
3391         options->add_remove = diff_addremove;
3392         options->use_color = diff_use_color_default;
3393         options->detect_rename = diff_detect_rename_default;
3394         options->xdl_opts |= diff_algorithm;
3395         if (diff_indent_heuristic)
3396                 DIFF_XDL_SET(options, INDENT_HEURISTIC);
3397
3398         options->orderfile = diff_order_file_cfg;
3399
3400         if (diff_no_prefix) {
3401                 options->a_prefix = options->b_prefix = "";
3402         } else if (!diff_mnemonic_prefix) {
3403                 options->a_prefix = "a/";
3404                 options->b_prefix = "b/";
3405         }
3406 }
3407
3408 void diff_setup_done(struct diff_options *options)
3409 {
3410         int count = 0;
3411
3412         if (options->set_default)
3413                 options->set_default(options);
3414
3415         if (options->output_format & DIFF_FORMAT_NAME)
3416                 count++;
3417         if (options->output_format & DIFF_FORMAT_NAME_STATUS)
3418                 count++;
3419         if (options->output_format & DIFF_FORMAT_CHECKDIFF)
3420                 count++;
3421         if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
3422                 count++;
3423         if (count > 1)
3424                 die(_("--name-only, --name-status, --check and -s are mutually exclusive"));
3425
3426         /*
3427          * Most of the time we can say "there are changes"
3428          * only by checking if there are changed paths, but
3429          * --ignore-whitespace* options force us to look
3430          * inside contents.
3431          */
3432
3433         if (DIFF_XDL_TST(options, IGNORE_WHITESPACE) ||
3434             DIFF_XDL_TST(options, IGNORE_WHITESPACE_CHANGE) ||
3435             DIFF_XDL_TST(options, IGNORE_WHITESPACE_AT_EOL))
3436                 DIFF_OPT_SET(options, DIFF_FROM_CONTENTS);
3437         else
3438                 DIFF_OPT_CLR(options, DIFF_FROM_CONTENTS);
3439
3440         if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
3441                 options->detect_rename = DIFF_DETECT_COPY;
3442
3443         if (!DIFF_OPT_TST(options, RELATIVE_NAME))
3444                 options->prefix = NULL;
3445         if (options->prefix)
3446                 options->prefix_length = strlen(options->prefix);
3447         else
3448                 options->prefix_length = 0;
3449
3450         if (options->output_format & (DIFF_FORMAT_NAME |
3451                                       DIFF_FORMAT_NAME_STATUS |
3452                                       DIFF_FORMAT_CHECKDIFF |
3453                                       DIFF_FORMAT_NO_OUTPUT))
3454                 options->output_format &= ~(DIFF_FORMAT_RAW |
3455                                             DIFF_FORMAT_NUMSTAT |
3456                                             DIFF_FORMAT_DIFFSTAT |
3457                                             DIFF_FORMAT_SHORTSTAT |
3458                                             DIFF_FORMAT_DIRSTAT |
3459                                             DIFF_FORMAT_SUMMARY |
3460                                             DIFF_FORMAT_PATCH);
3461
3462         /*
3463          * These cases always need recursive; we do not drop caller-supplied
3464          * recursive bits for other formats here.
3465          */
3466         if (options->output_format & (DIFF_FORMAT_PATCH |
3467                                       DIFF_FORMAT_NUMSTAT |
3468                                       DIFF_FORMAT_DIFFSTAT |
3469                                       DIFF_FORMAT_SHORTSTAT |
3470                                       DIFF_FORMAT_DIRSTAT |
3471                                       DIFF_FORMAT_SUMMARY |
3472                                       DIFF_FORMAT_CHECKDIFF))
3473                 DIFF_OPT_SET(options, RECURSIVE);
3474         /*
3475          * Also pickaxe would not work very well if you do not say recursive
3476          */
3477         if (options->pickaxe)
3478                 DIFF_OPT_SET(options, RECURSIVE);
3479         /*
3480          * When patches are generated, submodules diffed against the work tree
3481          * must be checked for dirtiness too so it can be shown in the output
3482          */
3483         if (options->output_format & DIFF_FORMAT_PATCH)
3484                 DIFF_OPT_SET(options, DIRTY_SUBMODULES);
3485
3486         if (options->detect_rename && options->rename_limit < 0)
3487                 options->rename_limit = diff_rename_limit_default;
3488         if (options->setup & DIFF_SETUP_USE_CACHE) {
3489                 if (!active_cache)
3490                         /* read-cache does not die even when it fails
3491                          * so it is safe for us to do this here.  Also
3492                          * it does not smudge active_cache or active_nr
3493                          * when it fails, so we do not have to worry about
3494                          * cleaning it up ourselves either.
3495                          */
3496                         read_cache();
3497         }
3498         if (40 < options->abbrev)
3499                 options->abbrev = 40; /* full */
3500
3501         /*
3502          * It does not make sense to show the first hit we happened
3503          * to have found.  It does not make sense not to return with
3504          * exit code in such a case either.
3505          */
3506         if (DIFF_OPT_TST(options, QUICK)) {
3507                 options->output_format = DIFF_FORMAT_NO_OUTPUT;
3508                 DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3509         }
3510
3511         options->diff_path_counter = 0;
3512
3513         if (DIFF_OPT_TST(options, FOLLOW_RENAMES) && options->pathspec.nr != 1)
3514                 die(_("--follow requires exactly one pathspec"));
3515 }
3516
3517 static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
3518 {
3519         char c, *eq;
3520         int len;
3521
3522         if (*arg != '-')
3523                 return 0;
3524         c = *++arg;
3525         if (!c)
3526                 return 0;
3527         if (c == arg_short) {
3528                 c = *++arg;
3529                 if (!c)
3530                         return 1;
3531                 if (val && isdigit(c)) {
3532                         char *end;
3533                         int n = strtoul(arg, &end, 10);
3534                         if (*end)
3535                                 return 0;
3536                         *val = n;
3537                         return 1;
3538                 }
3539                 return 0;
3540         }
3541         if (c != '-')
3542                 return 0;
3543         arg++;
3544         eq = strchrnul(arg, '=');
3545         len = eq - arg;
3546         if (!len || strncmp(arg, arg_long, len))
3547                 return 0;
3548         if (*eq) {
3549                 int n;
3550                 char *end;
3551                 if (!isdigit(*++eq))
3552                         return 0;
3553                 n = strtoul(eq, &end, 10);
3554                 if (*end)
3555                         return 0;
3556                 *val = n;
3557         }
3558         return 1;
3559 }
3560
3561 static int diff_scoreopt_parse(const char *opt);
3562
3563 static inline int short_opt(char opt, const char **argv,
3564                             const char **optarg)
3565 {
3566         const char *arg = argv[0];
3567         if (arg[0] != '-' || arg[1] != opt)
3568                 return 0;
3569         if (arg[2] != '\0') {
3570                 *optarg = arg + 2;
3571                 return 1;
3572         }
3573         if (!argv[1])
3574                 die("Option '%c' requires a value", opt);
3575         *optarg = argv[1];
3576         return 2;
3577 }
3578
3579 int parse_long_opt(const char *opt, const char **argv,
3580                    const char **optarg)
3581 {
3582         const char *arg = argv[0];
3583         if (!skip_prefix(arg, "--", &arg))
3584                 return 0;
3585         if (!skip_prefix(arg, opt, &arg))
3586                 return 0;
3587         if (*arg == '=') { /* stuck form: --option=value */
3588                 *optarg = arg + 1;
3589                 return 1;
3590         }
3591         if (*arg != '\0')
3592                 return 0;
3593         /* separate form: --option value */
3594         if (!argv[1])
3595                 die("Option '--%s' requires a value", opt);
3596         *optarg = argv[1];
3597         return 2;
3598 }
3599
3600 static int stat_opt(struct diff_options *options, const char **av)
3601 {
3602         const char *arg = av[0];
3603         char *end;
3604         int width = options->stat_width;
3605         int name_width = options->stat_name_width;
3606         int graph_width = options->stat_graph_width;
3607         int count = options->stat_count;
3608         int argcount = 1;
3609
3610         if (!skip_prefix(arg, "--stat", &arg))
3611                 die("BUG: stat option does not begin with --stat: %s", arg);
3612         end = (char *)arg;
3613
3614         switch (*arg) {
3615         case '-':
3616                 if (skip_prefix(arg, "-width", &arg)) {
3617                         if (*arg == '=')
3618                                 width = strtoul(arg + 1, &end, 10);
3619                         else if (!*arg && !av[1])
3620                                 die_want_option("--stat-width");
3621                         else if (!*arg) {
3622                                 width = strtoul(av[1], &end, 10);
3623                                 argcount = 2;
3624                         }
3625                 } else if (skip_prefix(arg, "-name-width", &arg)) {
3626                         if (*arg == '=')
3627                                 name_width = strtoul(arg + 1, &end, 10);
3628                         else if (!*arg && !av[1])
3629                                 die_want_option("--stat-name-width");
3630                         else if (!*arg) {
3631                                 name_width = strtoul(av[1], &end, 10);
3632                                 argcount = 2;
3633                         }
3634                 } else if (skip_prefix(arg, "-graph-width", &arg)) {
3635                         if (*arg == '=')
3636                                 graph_width = strtoul(arg + 1, &end, 10);
3637                         else if (!*arg && !av[1])
3638                                 die_want_option("--stat-graph-width");
3639                         else if (!*arg) {
3640                                 graph_width = strtoul(av[1], &end, 10);
3641                                 argcount = 2;
3642                         }
3643                 } else if (skip_prefix(arg, "-count", &arg)) {
3644                         if (*arg == '=')
3645                                 count = strtoul(arg + 1, &end, 10);
3646                         else if (!*arg && !av[1])
3647                                 die_want_option("--stat-count");
3648                         else if (!*arg) {
3649                                 count = strtoul(av[1], &end, 10);
3650                                 argcount = 2;
3651                         }
3652                 }
3653                 break;
3654         case '=':
3655                 width = strtoul(arg+1, &end, 10);
3656                 if (*end == ',')
3657                         name_width = strtoul(end+1, &end, 10);
3658                 if (*end == ',')
3659                         count = strtoul(end+1, &end, 10);
3660         }
3661
3662         /* Important! This checks all the error cases! */
3663         if (*end)
3664                 return 0;
3665         options->output_format |= DIFF_FORMAT_DIFFSTAT;
3666         options->stat_name_width = name_width;
3667         options->stat_graph_width = graph_width;
3668         options->stat_width = width;
3669         options->stat_count = count;
3670         return argcount;
3671 }
3672
3673 static int parse_dirstat_opt(struct diff_options *options, const char *params)
3674 {
3675         struct strbuf errmsg = STRBUF_INIT;
3676         if (parse_dirstat_params(options, params, &errmsg))
3677                 die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
3678                     errmsg.buf);
3679         strbuf_release(&errmsg);
3680         /*
3681          * The caller knows a dirstat-related option is given from the command
3682          * line; allow it to say "return this_function();"
3683          */
3684         options->output_format |= DIFF_FORMAT_DIRSTAT;
3685         return 1;
3686 }
3687
3688 static int parse_submodule_opt(struct diff_options *options, const char *value)
3689 {
3690         if (parse_submodule_params(options, value))
3691                 die(_("Failed to parse --submodule option parameter: '%s'"),
3692                         value);
3693         return 1;
3694 }
3695
3696 static const char diff_status_letters[] = {
3697         DIFF_STATUS_ADDED,
3698         DIFF_STATUS_COPIED,
3699         DIFF_STATUS_DELETED,
3700         DIFF_STATUS_MODIFIED,
3701         DIFF_STATUS_RENAMED,
3702         DIFF_STATUS_TYPE_CHANGED,
3703         DIFF_STATUS_UNKNOWN,
3704         DIFF_STATUS_UNMERGED,
3705         DIFF_STATUS_FILTER_AON,
3706         DIFF_STATUS_FILTER_BROKEN,
3707         '\0',
3708 };
3709
3710 static unsigned int filter_bit['Z' + 1];
3711
3712 static void prepare_filter_bits(void)
3713 {
3714         int i;
3715
3716         if (!filter_bit[DIFF_STATUS_ADDED]) {
3717                 for (i = 0; diff_status_letters[i]; i++)
3718                         filter_bit[(int) diff_status_letters[i]] = (1 << i);
3719         }
3720 }
3721
3722 static unsigned filter_bit_tst(char status, const struct diff_options *opt)
3723 {
3724         return opt->filter & filter_bit[(int) status];
3725 }
3726
3727 static int parse_diff_filter_opt(const char *optarg, struct diff_options *opt)
3728 {
3729         int i, optch;
3730
3731         prepare_filter_bits();
3732
3733         /*
3734          * If there is a negation e.g. 'd' in the input, and we haven't
3735          * initialized the filter field with another --diff-filter, start
3736          * from full set of bits, except for AON.
3737          */
3738         if (!opt->filter) {
3739                 for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3740                         if (optch < 'a' || 'z' < optch)
3741                                 continue;
3742                         opt->filter = (1 << (ARRAY_SIZE(diff_status_letters) - 1)) - 1;
3743                         opt->filter &= ~filter_bit[DIFF_STATUS_FILTER_AON];
3744                         break;
3745                 }
3746         }
3747
3748         for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3749                 unsigned int bit;
3750                 int negate;
3751
3752                 if ('a' <= optch && optch <= 'z') {
3753                         negate = 1;
3754                         optch = toupper(optch);
3755                 } else {
3756                         negate = 0;
3757                 }
3758
3759                 bit = (0 <= optch && optch <= 'Z') ? filter_bit[optch] : 0;
3760                 if (!bit)
3761                         return optarg[i];
3762                 if (negate)
3763                         opt->filter &= ~bit;
3764                 else
3765                         opt->filter |= bit;
3766         }
3767         return 0;
3768 }
3769
3770 static void enable_patch_output(int *fmt) {
3771         *fmt &= ~DIFF_FORMAT_NO_OUTPUT;
3772         *fmt |= DIFF_FORMAT_PATCH;
3773 }
3774
3775 static int parse_ws_error_highlight_opt(struct diff_options *opt, const char *arg)
3776 {
3777         int val = parse_ws_error_highlight(arg);
3778
3779         if (val < 0) {
3780                 error("unknown value after ws-error-highlight=%.*s",
3781                       -1 - val, arg);
3782                 return 0;
3783         }
3784         opt->ws_error_highlight = val;
3785         return 1;
3786 }
3787
3788 int diff_opt_parse(struct diff_options *options,
3789                    const char **av, int ac, const char *prefix)
3790 {
3791         const char *arg = av[0];
3792         const char *optarg;
3793         int argcount;
3794
3795         if (!prefix)
3796                 prefix = "";
3797
3798         /* Output format options */
3799         if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch")
3800             || opt_arg(arg, 'U', "unified", &options->context))
3801                 enable_patch_output(&options->output_format);
3802         else if (!strcmp(arg, "--raw"))
3803                 options->output_format |= DIFF_FORMAT_RAW;
3804         else if (!strcmp(arg, "--patch-with-raw")) {
3805                 enable_patch_output(&options->output_format);
3806                 options->output_format |= DIFF_FORMAT_RAW;
3807         } else if (!strcmp(arg, "--numstat"))
3808                 options->output_format |= DIFF_FORMAT_NUMSTAT;
3809         else if (!strcmp(arg, "--shortstat"))
3810                 options->output_format |= DIFF_FORMAT_SHORTSTAT;
3811         else if (!strcmp(arg, "-X") || !strcmp(arg, "--dirstat"))
3812                 return parse_dirstat_opt(options, "");
3813         else if (skip_prefix(arg, "-X", &arg))
3814                 return parse_dirstat_opt(options, arg);
3815         else if (skip_prefix(arg, "--dirstat=", &arg))
3816                 return parse_dirstat_opt(options, arg);
3817         else if (!strcmp(arg, "--cumulative"))
3818                 return parse_dirstat_opt(options, "cumulative");
3819         else if (!strcmp(arg, "--dirstat-by-file"))
3820                 return parse_dirstat_opt(options, "files");
3821         else if (skip_prefix(arg, "--dirstat-by-file=", &arg)) {
3822                 parse_dirstat_opt(options, "files");
3823                 return parse_dirstat_opt(options, arg);
3824         }
3825         else if (!strcmp(arg, "--check"))
3826                 options->output_format |= DIFF_FORMAT_CHECKDIFF;
3827         else if (!strcmp(arg, "--summary"))
3828                 options->output_format |= DIFF_FORMAT_SUMMARY;
3829         else if (!strcmp(arg, "--patch-with-stat")) {
3830                 enable_patch_output(&options->output_format);
3831                 options->output_format |= DIFF_FORMAT_DIFFSTAT;
3832         } else if (!strcmp(arg, "--name-only"))
3833                 options->output_format |= DIFF_FORMAT_NAME;
3834         else if (!strcmp(arg, "--name-status"))
3835                 options->output_format |= DIFF_FORMAT_NAME_STATUS;
3836         else if (!strcmp(arg, "-s") || !strcmp(arg, "--no-patch"))
3837                 options->output_format |= DIFF_FORMAT_NO_OUTPUT;
3838         else if (starts_with(arg, "--stat"))
3839                 /* --stat, --stat-width, --stat-name-width, or --stat-count */
3840                 return stat_opt(options, av);
3841
3842         /* renames options */
3843         else if (starts_with(arg, "-B") || starts_with(arg, "--break-rewrites=") ||
3844                  !strcmp(arg, "--break-rewrites")) {
3845                 if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
3846                         return error("invalid argument to -B: %s", arg+2);
3847         }
3848         else if (starts_with(arg, "-M") || starts_with(arg, "--find-renames=") ||
3849                  !strcmp(arg, "--find-renames")) {
3850                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3851                         return error("invalid argument to -M: %s", arg+2);
3852                 options->detect_rename = DIFF_DETECT_RENAME;
3853         }
3854         else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
3855                 options->irreversible_delete = 1;
3856         }
3857         else if (starts_with(arg, "-C") || starts_with(arg, "--find-copies=") ||
3858                  !strcmp(arg, "--find-copies")) {
3859                 if (options->detect_rename == DIFF_DETECT_COPY)
3860                         DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3861                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3862                         return error("invalid argument to -C: %s", arg+2);
3863                 options->detect_rename = DIFF_DETECT_COPY;
3864         }
3865         else if (!strcmp(arg, "--no-renames"))
3866                 options->detect_rename = 0;
3867         else if (!strcmp(arg, "--rename-empty"))
3868                 DIFF_OPT_SET(options, RENAME_EMPTY);
3869         else if (!strcmp(arg, "--no-rename-empty"))
3870                 DIFF_OPT_CLR(options, RENAME_EMPTY);
3871         else if (!strcmp(arg, "--relative"))
3872                 DIFF_OPT_SET(options, RELATIVE_NAME);
3873         else if (skip_prefix(arg, "--relative=", &arg)) {
3874                 DIFF_OPT_SET(options, RELATIVE_NAME);
3875                 options->prefix = arg;
3876         }
3877
3878         /* xdiff options */
3879         else if (!strcmp(arg, "--minimal"))
3880                 DIFF_XDL_SET(options, NEED_MINIMAL);
3881         else if (!strcmp(arg, "--no-minimal"))
3882                 DIFF_XDL_CLR(options, NEED_MINIMAL);
3883         else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
3884                 DIFF_XDL_SET(options, IGNORE_WHITESPACE);
3885         else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
3886                 DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
3887         else if (!strcmp(arg, "--ignore-space-at-eol"))
3888                 DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
3889         else if (!strcmp(arg, "--ignore-blank-lines"))
3890                 DIFF_XDL_SET(options, IGNORE_BLANK_LINES);
3891         else if (!strcmp(arg, "--indent-heuristic"))
3892                 DIFF_XDL_SET(options, INDENT_HEURISTIC);
3893         else if (!strcmp(arg, "--no-indent-heuristic"))
3894                 DIFF_XDL_CLR(options, INDENT_HEURISTIC);
3895         else if (!strcmp(arg, "--patience"))
3896                 options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
3897         else if (!strcmp(arg, "--histogram"))
3898                 options->xdl_opts = DIFF_WITH_ALG(options, HISTOGRAM_DIFF);
3899         else if ((argcount = parse_long_opt("diff-algorithm", av, &optarg))) {
3900                 long value = parse_algorithm_value(optarg);
3901                 if (value < 0)
3902                         return error("option diff-algorithm accepts \"myers\", "
3903                                      "\"minimal\", \"patience\" and \"histogram\"");
3904                 /* clear out previous settings */
3905                 DIFF_XDL_CLR(options, NEED_MINIMAL);
3906                 options->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
3907                 options->xdl_opts |= value;
3908                 return argcount;
3909         }
3910
3911         /* flags options */
3912         else if (!strcmp(arg, "--binary")) {
3913                 enable_patch_output(&options->output_format);
3914                 DIFF_OPT_SET(options, BINARY);
3915         }
3916         else if (!strcmp(arg, "--full-index"))
3917                 DIFF_OPT_SET(options, FULL_INDEX);
3918         else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
3919                 DIFF_OPT_SET(options, TEXT);
3920         else if (!strcmp(arg, "-R"))
3921                 DIFF_OPT_SET(options, REVERSE_DIFF);
3922         else if (!strcmp(arg, "--find-copies-harder"))
3923                 DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3924         else if (!strcmp(arg, "--follow"))
3925                 DIFF_OPT_SET(options, FOLLOW_RENAMES);
3926         else if (!strcmp(arg, "--no-follow")) {
3927                 DIFF_OPT_CLR(options, FOLLOW_RENAMES);
3928                 DIFF_OPT_CLR(options, DEFAULT_FOLLOW_RENAMES);
3929         } else if (!strcmp(arg, "--color"))
3930                 options->use_color = 1;
3931         else if (skip_prefix(arg, "--color=", &arg)) {
3932                 int value = git_config_colorbool(NULL, arg);
3933                 if (value < 0)
3934                         return error("option `color' expects \"always\", \"auto\", or \"never\"");
3935                 options->use_color = value;
3936         }
3937         else if (!strcmp(arg, "--no-color"))
3938                 options->use_color = 0;
3939         else if (!strcmp(arg, "--color-words")) {
3940                 options->use_color = 1;
3941                 options->word_diff = DIFF_WORDS_COLOR;
3942         }
3943         else if (skip_prefix(arg, "--color-words=", &arg)) {
3944                 options->use_color = 1;
3945                 options->word_diff = DIFF_WORDS_COLOR;
3946                 options->word_regex = arg;
3947         }
3948         else if (!strcmp(arg, "--word-diff")) {
3949                 if (options->word_diff == DIFF_WORDS_NONE)
3950                         options->word_diff = DIFF_WORDS_PLAIN;
3951         }
3952         else if (skip_prefix(arg, "--word-diff=", &arg)) {
3953                 if (!strcmp(arg, "plain"))
3954                         options->word_diff = DIFF_WORDS_PLAIN;
3955                 else if (!strcmp(arg, "color")) {
3956                         options->use_color = 1;
3957                         options->word_diff = DIFF_WORDS_COLOR;
3958                 }
3959                 else if (!strcmp(arg, "porcelain"))
3960                         options->word_diff = DIFF_WORDS_PORCELAIN;
3961                 else if (!strcmp(arg, "none"))
3962                         options->word_diff = DIFF_WORDS_NONE;
3963                 else
3964                         die("bad --word-diff argument: %s", arg);
3965         }
3966         else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
3967                 if (options->word_diff == DIFF_WORDS_NONE)
3968                         options->word_diff = DIFF_WORDS_PLAIN;
3969                 options->word_regex = optarg;
3970                 return argcount;
3971         }
3972         else if (!strcmp(arg, "--exit-code"))
3973                 DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3974         else if (!strcmp(arg, "--quiet"))
3975                 DIFF_OPT_SET(options, QUICK);
3976         else if (!strcmp(arg, "--ext-diff"))
3977                 DIFF_OPT_SET(options, ALLOW_EXTERNAL);
3978         else if (!strcmp(arg, "--no-ext-diff"))
3979                 DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
3980         else if (!strcmp(arg, "--textconv"))
3981                 DIFF_OPT_SET(options, ALLOW_TEXTCONV);
3982         else if (!strcmp(arg, "--no-textconv"))
3983                 DIFF_OPT_CLR(options, ALLOW_TEXTCONV);
3984         else if (!strcmp(arg, "--ignore-submodules")) {
3985                 DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3986                 handle_ignore_submodules_arg(options, "all");
3987         } else if (skip_prefix(arg, "--ignore-submodules=", &arg)) {
3988                 DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3989                 handle_ignore_submodules_arg(options, arg);
3990         } else if (!strcmp(arg, "--submodule"))
3991                 options->submodule_format = DIFF_SUBMODULE_LOG;
3992         else if (skip_prefix(arg, "--submodule=", &arg))
3993                 return parse_submodule_opt(options, arg);
3994         else if (skip_prefix(arg, "--ws-error-highlight=", &arg))
3995                 return parse_ws_error_highlight_opt(options, arg);
3996         else if (!strcmp(arg, "--ita-invisible-in-index"))
3997                 options->ita_invisible_in_index = 1;
3998         else if (!strcmp(arg, "--ita-visible-in-index"))
3999                 options->ita_invisible_in_index = 0;
4000
4001         /* misc options */
4002         else if (!strcmp(arg, "-z"))
4003                 options->line_termination = 0;
4004         else if ((argcount = short_opt('l', av, &optarg))) {
4005                 options->rename_limit = strtoul(optarg, NULL, 10);
4006                 return argcount;
4007         }
4008         else if ((argcount = short_opt('S', av, &optarg))) {
4009                 options->pickaxe = optarg;
4010                 options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
4011                 return argcount;
4012         } else if ((argcount = short_opt('G', av, &optarg))) {
4013                 options->pickaxe = optarg;
4014                 options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
4015                 return argcount;
4016         }
4017         else if (!strcmp(arg, "--pickaxe-all"))
4018                 options->pickaxe_opts |= DIFF_PICKAXE_ALL;
4019         else if (!strcmp(arg, "--pickaxe-regex"))
4020                 options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
4021         else if ((argcount = short_opt('O', av, &optarg))) {
4022                 options->orderfile = prefix_filename(prefix, optarg);
4023                 return argcount;
4024         }
4025         else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
4026                 int offending = parse_diff_filter_opt(optarg, options);
4027                 if (offending)
4028                         die("unknown change class '%c' in --diff-filter=%s",
4029                             offending, optarg);
4030                 return argcount;
4031         }
4032         else if (!strcmp(arg, "--no-abbrev"))
4033                 options->abbrev = 0;
4034         else if (!strcmp(arg, "--abbrev"))
4035                 options->abbrev = DEFAULT_ABBREV;
4036         else if (skip_prefix(arg, "--abbrev=", &arg)) {
4037                 options->abbrev = strtoul(arg, NULL, 10);
4038                 if (options->abbrev < MINIMUM_ABBREV)
4039                         options->abbrev = MINIMUM_ABBREV;
4040                 else if (40 < options->abbrev)
4041                         options->abbrev = 40;
4042         }
4043         else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
4044                 options->a_prefix = optarg;
4045                 return argcount;
4046         }
4047         else if ((argcount = parse_long_opt("line-prefix", av, &optarg))) {
4048                 options->line_prefix = optarg;
4049                 options->line_prefix_length = strlen(options->line_prefix);
4050                 graph_setup_line_prefix(options);
4051                 return argcount;
4052         }
4053         else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
4054                 options->b_prefix = optarg;
4055                 return argcount;
4056         }
4057         else if (!strcmp(arg, "--no-prefix"))
4058                 options->a_prefix = options->b_prefix = "";
4059         else if (opt_arg(arg, '\0', "inter-hunk-context",
4060                          &options->interhunkcontext))
4061                 ;
4062         else if (!strcmp(arg, "-W"))
4063                 DIFF_OPT_SET(options, FUNCCONTEXT);
4064         else if (!strcmp(arg, "--function-context"))
4065                 DIFF_OPT_SET(options, FUNCCONTEXT);
4066         else if (!strcmp(arg, "--no-function-context"))
4067                 DIFF_OPT_CLR(options, FUNCCONTEXT);
4068         else if ((argcount = parse_long_opt("output", av, &optarg))) {
4069                 char *path = prefix_filename(prefix, optarg);
4070                 options->file = xfopen(path, "w");
4071                 options->close_file = 1;
4072                 if (options->use_color != GIT_COLOR_ALWAYS)
4073                         options->use_color = GIT_COLOR_NEVER;
4074                 free(path);
4075                 return argcount;
4076         } else
4077                 return 0;
4078         return 1;
4079 }
4080
4081 int parse_rename_score(const char **cp_p)
4082 {
4083         unsigned long num, scale;
4084         int ch, dot;
4085         const char *cp = *cp_p;
4086
4087         num = 0;
4088         scale = 1;
4089         dot = 0;
4090         for (;;) {
4091                 ch = *cp;
4092                 if ( !dot && ch == '.' ) {
4093                         scale = 1;
4094                         dot = 1;
4095                 } else if ( ch == '%' ) {
4096                         scale = dot ? scale*100 : 100;
4097                         cp++;   /* % is always at the end */
4098                         break;
4099                 } else if ( ch >= '0' && ch <= '9' ) {
4100                         if ( scale < 100000 ) {
4101                                 scale *= 10;
4102                                 num = (num*10) + (ch-'0');
4103                         }
4104                 } else {
4105                         break;
4106                 }
4107                 cp++;
4108         }
4109         *cp_p = cp;
4110
4111         /* user says num divided by scale and we say internally that
4112          * is MAX_SCORE * num / scale.
4113          */
4114         return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
4115 }
4116
4117 static int diff_scoreopt_parse(const char *opt)
4118 {
4119         int opt1, opt2, cmd;
4120
4121         if (*opt++ != '-')
4122                 return -1;
4123         cmd = *opt++;
4124         if (cmd == '-') {
4125                 /* convert the long-form arguments into short-form versions */
4126                 if (skip_prefix(opt, "break-rewrites", &opt)) {
4127                         if (*opt == 0 || *opt++ == '=')
4128                                 cmd = 'B';
4129                 } else if (skip_prefix(opt, "find-copies", &opt)) {
4130                         if (*opt == 0 || *opt++ == '=')
4131                                 cmd = 'C';
4132                 } else if (skip_prefix(opt, "find-renames", &opt)) {
4133                         if (*opt == 0 || *opt++ == '=')
4134                                 cmd = 'M';
4135                 }
4136         }
4137         if (cmd != 'M' && cmd != 'C' && cmd != 'B')
4138                 return -1; /* that is not a -M, -C, or -B option */
4139
4140         opt1 = parse_rename_score(&opt);
4141         if (cmd != 'B')
4142                 opt2 = 0;
4143         else {
4144                 if (*opt == 0)
4145                         opt2 = 0;
4146                 else if (*opt != '/')
4147                         return -1; /* we expect -B80/99 or -B80 */
4148                 else {
4149                         opt++;
4150                         opt2 = parse_rename_score(&opt);
4151                 }
4152         }
4153         if (*opt != 0)
4154                 return -1;
4155         return opt1 | (opt2 << 16);
4156 }
4157
4158 struct diff_queue_struct diff_queued_diff;
4159
4160 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
4161 {
4162         ALLOC_GROW(queue->queue, queue->nr + 1, queue->alloc);
4163         queue->queue[queue->nr++] = dp;
4164 }
4165
4166 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
4167                                  struct diff_filespec *one,
4168                                  struct diff_filespec *two)
4169 {
4170         struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
4171         dp->one = one;
4172         dp->two = two;
4173         if (queue)
4174                 diff_q(queue, dp);
4175         return dp;
4176 }
4177
4178 void diff_free_filepair(struct diff_filepair *p)
4179 {
4180         free_filespec(p->one);
4181         free_filespec(p->two);
4182         free(p);
4183 }
4184
4185 const char *diff_aligned_abbrev(const struct object_id *oid, int len)
4186 {
4187         int abblen;
4188         const char *abbrev;
4189
4190         if (len == GIT_SHA1_HEXSZ)
4191                 return oid_to_hex(oid);
4192
4193         abbrev = diff_abbrev_oid(oid, len);
4194         abblen = strlen(abbrev);
4195
4196         /*
4197          * In well-behaved cases, where the abbbreviated result is the
4198          * same as the requested length, append three dots after the
4199          * abbreviation (hence the whole logic is limited to the case
4200          * where abblen < 37); when the actual abbreviated result is a
4201          * bit longer than the requested length, we reduce the number
4202          * of dots so that they match the well-behaved ones.  However,
4203          * if the actual abbreviation is longer than the requested
4204          * length by more than three, we give up on aligning, and add
4205          * three dots anyway, to indicate that the output is not the
4206          * full object name.  Yes, this may be suboptimal, but this
4207          * appears only in "diff --raw --abbrev" output and it is not
4208          * worth the effort to change it now.  Note that this would
4209          * likely to work fine when the automatic sizing of default
4210          * abbreviation length is used--we would be fed -1 in "len" in
4211          * that case, and will end up always appending three-dots, but
4212          * the automatic sizing is supposed to give abblen that ensures
4213          * uniqueness across all objects (statistically speaking).
4214          */
4215         if (abblen < GIT_SHA1_HEXSZ - 3) {
4216                 static char hex[GIT_MAX_HEXSZ + 1];
4217                 if (len < abblen && abblen <= len + 2)
4218                         xsnprintf(hex, sizeof(hex), "%s%.*s", abbrev, len+3-abblen, "..");
4219                 else
4220                         xsnprintf(hex, sizeof(hex), "%s...", abbrev);
4221                 return hex;
4222         }
4223
4224         return oid_to_hex(oid);
4225 }
4226
4227 static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
4228 {
4229         int line_termination = opt->line_termination;
4230         int inter_name_termination = line_termination ? '\t' : '\0';
4231
4232         fprintf(opt->file, "%s", diff_line_prefix(opt));
4233         if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
4234                 fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
4235                         diff_aligned_abbrev(&p->one->oid, opt->abbrev));
4236                 fprintf(opt->file, "%s ",
4237                         diff_aligned_abbrev(&p->two->oid, opt->abbrev));
4238         }
4239         if (p->score) {
4240                 fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
4241                         inter_name_termination);
4242         } else {
4243                 fprintf(opt->file, "%c%c", p->status, inter_name_termination);
4244         }
4245
4246         if (p->status == DIFF_STATUS_COPIED ||
4247             p->status == DIFF_STATUS_RENAMED) {
4248                 const char *name_a, *name_b;
4249                 name_a = p->one->path;
4250                 name_b = p->two->path;
4251                 strip_prefix(opt->prefix_length, &name_a, &name_b);
4252                 write_name_quoted(name_a, opt->file, inter_name_termination);
4253                 write_name_quoted(name_b, opt->file, line_termination);
4254         } else {
4255                 const char *name_a, *name_b;
4256                 name_a = p->one->mode ? p->one->path : p->two->path;
4257                 name_b = NULL;
4258                 strip_prefix(opt->prefix_length, &name_a, &name_b);
4259                 write_name_quoted(name_a, opt->file, line_termination);
4260         }
4261 }
4262
4263 int diff_unmodified_pair(struct diff_filepair *p)
4264 {
4265         /* This function is written stricter than necessary to support
4266          * the currently implemented transformers, but the idea is to
4267          * let transformers to produce diff_filepairs any way they want,
4268          * and filter and clean them up here before producing the output.
4269          */
4270         struct diff_filespec *one = p->one, *two = p->two;
4271
4272         if (DIFF_PAIR_UNMERGED(p))
4273                 return 0; /* unmerged is interesting */
4274
4275         /* deletion, addition, mode or type change
4276          * and rename are all interesting.
4277          */
4278         if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
4279             DIFF_PAIR_MODE_CHANGED(p) ||
4280             strcmp(one->path, two->path))
4281                 return 0;
4282
4283         /* both are valid and point at the same path.  that is, we are
4284          * dealing with a change.
4285          */
4286         if (one->oid_valid && two->oid_valid &&
4287             !oidcmp(&one->oid, &two->oid) &&
4288             !one->dirty_submodule && !two->dirty_submodule)
4289                 return 1; /* no change */
4290         if (!one->oid_valid && !two->oid_valid)
4291                 return 1; /* both look at the same file on the filesystem. */
4292         return 0;
4293 }
4294
4295 static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
4296 {
4297         if (diff_unmodified_pair(p))
4298                 return;
4299
4300         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4301             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4302                 return; /* no tree diffs in patch format */
4303
4304         run_diff(p, o);
4305 }
4306
4307 static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
4308                             struct diffstat_t *diffstat)
4309 {
4310         if (diff_unmodified_pair(p))
4311                 return;
4312
4313         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4314             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4315                 return; /* no useful stat for tree diffs */
4316
4317         run_diffstat(p, o, diffstat);
4318 }
4319
4320 static void diff_flush_checkdiff(struct diff_filepair *p,
4321                 struct diff_options *o)
4322 {
4323         if (diff_unmodified_pair(p))
4324                 return;
4325
4326         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4327             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4328                 return; /* nothing to check in tree diffs */
4329
4330         run_checkdiff(p, o);
4331 }
4332
4333 int diff_queue_is_empty(void)
4334 {
4335         struct diff_queue_struct *q = &diff_queued_diff;
4336         int i;
4337         for (i = 0; i < q->nr; i++)
4338                 if (!diff_unmodified_pair(q->queue[i]))
4339                         return 0;
4340         return 1;
4341 }
4342
4343 #if DIFF_DEBUG
4344 void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
4345 {
4346         fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
4347                 x, one ? one : "",
4348                 s->path,
4349                 DIFF_FILE_VALID(s) ? "valid" : "invalid",
4350                 s->mode,
4351                 s->oid_valid ? oid_to_hex(&s->oid) : "");
4352         fprintf(stderr, "queue[%d] %s size %lu\n",
4353                 x, one ? one : "",
4354                 s->size);
4355 }
4356
4357 void diff_debug_filepair(const struct diff_filepair *p, int i)
4358 {
4359         diff_debug_filespec(p->one, i, "one");
4360         diff_debug_filespec(p->two, i, "two");
4361         fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
4362                 p->score, p->status ? p->status : '?',
4363                 p->one->rename_used, p->broken_pair);
4364 }
4365
4366 void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
4367 {
4368         int i;
4369         if (msg)
4370                 fprintf(stderr, "%s\n", msg);
4371         fprintf(stderr, "q->nr = %d\n", q->nr);
4372         for (i = 0; i < q->nr; i++) {
4373                 struct diff_filepair *p = q->queue[i];
4374                 diff_debug_filepair(p, i);
4375         }
4376 }
4377 #endif
4378
4379 static void diff_resolve_rename_copy(void)
4380 {
4381         int i;
4382         struct diff_filepair *p;
4383         struct diff_queue_struct *q = &diff_queued_diff;
4384
4385         diff_debug_queue("resolve-rename-copy", q);
4386
4387         for (i = 0; i < q->nr; i++) {
4388                 p = q->queue[i];
4389                 p->status = 0; /* undecided */
4390                 if (DIFF_PAIR_UNMERGED(p))
4391                         p->status = DIFF_STATUS_UNMERGED;
4392                 else if (!DIFF_FILE_VALID(p->one))
4393                         p->status = DIFF_STATUS_ADDED;
4394                 else if (!DIFF_FILE_VALID(p->two))
4395                         p->status = DIFF_STATUS_DELETED;
4396                 else if (DIFF_PAIR_TYPE_CHANGED(p))
4397                         p->status = DIFF_STATUS_TYPE_CHANGED;
4398
4399                 /* from this point on, we are dealing with a pair
4400                  * whose both sides are valid and of the same type, i.e.
4401                  * either in-place edit or rename/copy edit.
4402                  */
4403                 else if (DIFF_PAIR_RENAME(p)) {
4404                         /*
4405                          * A rename might have re-connected a broken
4406                          * pair up, causing the pathnames to be the
4407                          * same again. If so, that's not a rename at
4408                          * all, just a modification..
4409                          *
4410                          * Otherwise, see if this source was used for
4411                          * multiple renames, in which case we decrement
4412                          * the count, and call it a copy.
4413                          */
4414                         if (!strcmp(p->one->path, p->two->path))
4415                                 p->status = DIFF_STATUS_MODIFIED;
4416                         else if (--p->one->rename_used > 0)
4417                                 p->status = DIFF_STATUS_COPIED;
4418                         else
4419                                 p->status = DIFF_STATUS_RENAMED;
4420                 }
4421                 else if (oidcmp(&p->one->oid, &p->two->oid) ||
4422                          p->one->mode != p->two->mode ||
4423                          p->one->dirty_submodule ||
4424                          p->two->dirty_submodule ||
4425                          is_null_oid(&p->one->oid))
4426                         p->status = DIFF_STATUS_MODIFIED;
4427                 else {
4428                         /* This is a "no-change" entry and should not
4429                          * happen anymore, but prepare for broken callers.
4430                          */
4431                         error("feeding unmodified %s to diffcore",
4432                               p->one->path);
4433                         p->status = DIFF_STATUS_UNKNOWN;
4434                 }
4435         }
4436         diff_debug_queue("resolve-rename-copy done", q);
4437 }
4438
4439 static int check_pair_status(struct diff_filepair *p)
4440 {
4441         switch (p->status) {
4442         case DIFF_STATUS_UNKNOWN:
4443                 return 0;
4444         case 0:
4445                 die("internal error in diff-resolve-rename-copy");
4446         default:
4447                 return 1;
4448         }
4449 }
4450
4451 static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
4452 {
4453         int fmt = opt->output_format;
4454
4455         if (fmt & DIFF_FORMAT_CHECKDIFF)
4456                 diff_flush_checkdiff(p, opt);
4457         else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
4458                 diff_flush_raw(p, opt);
4459         else if (fmt & DIFF_FORMAT_NAME) {
4460                 const char *name_a, *name_b;
4461                 name_a = p->two->path;
4462                 name_b = NULL;
4463                 strip_prefix(opt->prefix_length, &name_a, &name_b);
4464                 fprintf(opt->file, "%s", diff_line_prefix(opt));
4465                 write_name_quoted(name_a, opt->file, opt->line_termination);
4466         }
4467 }
4468
4469 static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
4470 {
4471         if (fs->mode)
4472                 fprintf(file, " %s mode %06o ", newdelete, fs->mode);
4473         else
4474                 fprintf(file, " %s ", newdelete);
4475         write_name_quoted(fs->path, file, '\n');
4476 }
4477
4478
4479 static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name,
4480                 const char *line_prefix)
4481 {
4482         if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
4483                 fprintf(file, "%s mode change %06o => %06o%c", line_prefix, p->one->mode,
4484                         p->two->mode, show_name ? ' ' : '\n');
4485                 if (show_name) {
4486                         write_name_quoted(p->two->path, file, '\n');
4487                 }
4488         }
4489 }
4490
4491 static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p,
4492                         const char *line_prefix)
4493 {
4494         char *names = pprint_rename(p->one->path, p->two->path);
4495
4496         fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
4497         free(names);
4498         show_mode_change(file, p, 0, line_prefix);
4499 }
4500
4501 static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
4502 {
4503         FILE *file = opt->file;
4504         const char *line_prefix = diff_line_prefix(opt);
4505
4506         switch(p->status) {
4507         case DIFF_STATUS_DELETED:
4508                 fputs(line_prefix, file);
4509                 show_file_mode_name(file, "delete", p->one);
4510                 break;
4511         case DIFF_STATUS_ADDED:
4512                 fputs(line_prefix, file);
4513                 show_file_mode_name(file, "create", p->two);
4514                 break;
4515         case DIFF_STATUS_COPIED:
4516                 fputs(line_prefix, file);
4517                 show_rename_copy(file, "copy", p, line_prefix);
4518                 break;
4519         case DIFF_STATUS_RENAMED:
4520                 fputs(line_prefix, file);
4521                 show_rename_copy(file, "rename", p, line_prefix);
4522                 break;
4523         default:
4524                 if (p->score) {
4525                         fprintf(file, "%s rewrite ", line_prefix);
4526                         write_name_quoted(p->two->path, file, ' ');
4527                         fprintf(file, "(%d%%)\n", similarity_index(p));
4528                 }
4529                 show_mode_change(file, p, !p->score, line_prefix);
4530                 break;
4531         }
4532 }
4533
4534 struct patch_id_t {
4535         git_SHA_CTX *ctx;
4536         int patchlen;
4537 };
4538
4539 static int remove_space(char *line, int len)
4540 {
4541         int i;
4542         char *dst = line;
4543         unsigned char c;
4544
4545         for (i = 0; i < len; i++)
4546                 if (!isspace((c = line[i])))
4547                         *dst++ = c;
4548
4549         return dst - line;
4550 }
4551
4552 static void patch_id_consume(void *priv, char *line, unsigned long len)
4553 {
4554         struct patch_id_t *data = priv;
4555         int new_len;
4556
4557         /* Ignore line numbers when computing the SHA1 of the patch */
4558         if (starts_with(line, "@@ -"))
4559                 return;
4560
4561         new_len = remove_space(line, len);
4562
4563         git_SHA1_Update(data->ctx, line, new_len);
4564         data->patchlen += new_len;
4565 }
4566
4567 static void patch_id_add_string(git_SHA_CTX *ctx, const char *str)
4568 {
4569         git_SHA1_Update(ctx, str, strlen(str));
4570 }
4571
4572 static void patch_id_add_mode(git_SHA_CTX *ctx, unsigned mode)
4573 {
4574         /* large enough for 2^32 in octal */
4575         char buf[12];
4576         int len = xsnprintf(buf, sizeof(buf), "%06o", mode);
4577         git_SHA1_Update(ctx, buf, len);
4578 }
4579
4580 /* returns 0 upon success, and writes result into sha1 */
4581 static int diff_get_patch_id(struct diff_options *options, struct object_id *oid, int diff_header_only)
4582 {
4583         struct diff_queue_struct *q = &diff_queued_diff;
4584         int i;
4585         git_SHA_CTX ctx;
4586         struct patch_id_t data;
4587
4588         git_SHA1_Init(&ctx);
4589         memset(&data, 0, sizeof(struct patch_id_t));
4590         data.ctx = &ctx;
4591
4592         for (i = 0; i < q->nr; i++) {
4593                 xpparam_t xpp;
4594                 xdemitconf_t xecfg;
4595                 mmfile_t mf1, mf2;
4596                 struct diff_filepair *p = q->queue[i];
4597                 int len1, len2;
4598
4599                 memset(&xpp, 0, sizeof(xpp));
4600                 memset(&xecfg, 0, sizeof(xecfg));
4601                 if (p->status == 0)
4602                         return error("internal diff status error");
4603                 if (p->status == DIFF_STATUS_UNKNOWN)
4604                         continue;
4605                 if (diff_unmodified_pair(p))
4606                         continue;
4607                 if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4608                     (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4609                         continue;
4610                 if (DIFF_PAIR_UNMERGED(p))
4611                         continue;
4612
4613                 diff_fill_oid_info(p->one);
4614                 diff_fill_oid_info(p->two);
4615
4616                 len1 = remove_space(p->one->path, strlen(p->one->path));
4617                 len2 = remove_space(p->two->path, strlen(p->two->path));
4618                 patch_id_add_string(&ctx, "diff--git");
4619                 patch_id_add_string(&ctx, "a/");
4620                 git_SHA1_Update(&ctx, p->one->path, len1);
4621                 patch_id_add_string(&ctx, "b/");
4622                 git_SHA1_Update(&ctx, p->two->path, len2);
4623
4624                 if (p->one->mode == 0) {
4625                         patch_id_add_string(&ctx, "newfilemode");
4626                         patch_id_add_mode(&ctx, p->two->mode);
4627                         patch_id_add_string(&ctx, "---/dev/null");
4628                         patch_id_add_string(&ctx, "+++b/");
4629                         git_SHA1_Update(&ctx, p->two->path, len2);
4630                 } else if (p->two->mode == 0) {
4631                         patch_id_add_string(&ctx, "deletedfilemode");
4632                         patch_id_add_mode(&ctx, p->one->mode);
4633                         patch_id_add_string(&ctx, "---a/");
4634                         git_SHA1_Update(&ctx, p->one->path, len1);
4635                         patch_id_add_string(&ctx, "+++/dev/null");
4636                 } else {
4637                         patch_id_add_string(&ctx, "---a/");
4638                         git_SHA1_Update(&ctx, p->one->path, len1);
4639                         patch_id_add_string(&ctx, "+++b/");
4640                         git_SHA1_Update(&ctx, p->two->path, len2);
4641                 }
4642
4643                 if (diff_header_only)
4644                         continue;
4645
4646                 if (fill_mmfile(&mf1, p->one) < 0 ||
4647                     fill_mmfile(&mf2, p->two) < 0)
4648                         return error("unable to read files to diff");
4649
4650                 if (diff_filespec_is_binary(p->one) ||
4651                     diff_filespec_is_binary(p->two)) {
4652                         git_SHA1_Update(&ctx, oid_to_hex(&p->one->oid),
4653                                         GIT_SHA1_HEXSZ);
4654                         git_SHA1_Update(&ctx, oid_to_hex(&p->two->oid),
4655                                         GIT_SHA1_HEXSZ);
4656                         continue;
4657                 }
4658
4659                 xpp.flags = 0;
4660                 xecfg.ctxlen = 3;
4661                 xecfg.flags = 0;
4662                 if (xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
4663                                   &xpp, &xecfg))
4664                         return error("unable to generate patch-id diff for %s",
4665                                      p->one->path);
4666         }
4667
4668         git_SHA1_Final(oid->hash, &ctx);
4669         return 0;
4670 }
4671
4672 int diff_flush_patch_id(struct diff_options *options, struct object_id *oid, int diff_header_only)
4673 {
4674         struct diff_queue_struct *q = &diff_queued_diff;
4675         int i;
4676         int result = diff_get_patch_id(options, oid, diff_header_only);
4677
4678         for (i = 0; i < q->nr; i++)
4679                 diff_free_filepair(q->queue[i]);
4680
4681         free(q->queue);
4682         DIFF_QUEUE_CLEAR(q);
4683
4684         return result;
4685 }
4686
4687 static int is_summary_empty(const struct diff_queue_struct *q)
4688 {
4689         int i;
4690
4691         for (i = 0; i < q->nr; i++) {
4692                 const struct diff_filepair *p = q->queue[i];
4693
4694                 switch (p->status) {
4695                 case DIFF_STATUS_DELETED:
4696                 case DIFF_STATUS_ADDED:
4697                 case DIFF_STATUS_COPIED:
4698                 case DIFF_STATUS_RENAMED:
4699                         return 0;
4700                 default:
4701                         if (p->score)
4702                                 return 0;
4703                         if (p->one->mode && p->two->mode &&
4704                             p->one->mode != p->two->mode)
4705                                 return 0;
4706                         break;
4707                 }
4708         }
4709         return 1;
4710 }
4711
4712 static const char rename_limit_warning[] =
4713 N_("inexact rename detection was skipped due to too many files.");
4714
4715 static const char degrade_cc_to_c_warning[] =
4716 N_("only found copies from modified paths due to too many files.");
4717
4718 static const char rename_limit_advice[] =
4719 N_("you may want to set your %s variable to at least "
4720    "%d and retry the command.");
4721
4722 void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
4723 {
4724         if (degraded_cc)
4725                 warning(_(degrade_cc_to_c_warning));
4726         else if (needed)
4727                 warning(_(rename_limit_warning));
4728         else
4729                 return;
4730         if (0 < needed && needed < 32767)
4731                 warning(_(rename_limit_advice), varname, needed);
4732 }
4733
4734 void diff_flush(struct diff_options *options)
4735 {
4736         struct diff_queue_struct *q = &diff_queued_diff;
4737         int i, output_format = options->output_format;
4738         int separator = 0;
4739         int dirstat_by_line = 0;
4740
4741         /*
4742          * Order: raw, stat, summary, patch
4743          * or:    name/name-status/checkdiff (other bits clear)
4744          */
4745         if (!q->nr)
4746                 goto free_queue;
4747
4748         if (output_format & (DIFF_FORMAT_RAW |
4749                              DIFF_FORMAT_NAME |
4750                              DIFF_FORMAT_NAME_STATUS |
4751                              DIFF_FORMAT_CHECKDIFF)) {
4752                 for (i = 0; i < q->nr; i++) {
4753                         struct diff_filepair *p = q->queue[i];
4754                         if (check_pair_status(p))
4755                                 flush_one_pair(p, options);
4756                 }
4757                 separator++;
4758         }
4759
4760         if (output_format & DIFF_FORMAT_DIRSTAT && DIFF_OPT_TST(options, DIRSTAT_BY_LINE))
4761                 dirstat_by_line = 1;
4762
4763         if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
4764             dirstat_by_line) {
4765                 struct diffstat_t diffstat;
4766
4767                 memset(&diffstat, 0, sizeof(struct diffstat_t));
4768                 for (i = 0; i < q->nr; i++) {
4769                         struct diff_filepair *p = q->queue[i];
4770                         if (check_pair_status(p))
4771                                 diff_flush_stat(p, options, &diffstat);
4772                 }
4773                 if (output_format & DIFF_FORMAT_NUMSTAT)
4774                         show_numstat(&diffstat, options);
4775                 if (output_format & DIFF_FORMAT_DIFFSTAT)
4776                         show_stats(&diffstat, options);
4777                 if (output_format & DIFF_FORMAT_SHORTSTAT)
4778                         show_shortstats(&diffstat, options);
4779                 if (output_format & DIFF_FORMAT_DIRSTAT && dirstat_by_line)
4780                         show_dirstat_by_line(&diffstat, options);
4781                 free_diffstat_info(&diffstat);
4782                 separator++;
4783         }
4784         if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
4785                 show_dirstat(options);
4786
4787         if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
4788                 for (i = 0; i < q->nr; i++) {
4789                         diff_summary(options, q->queue[i]);
4790                 }
4791                 separator++;
4792         }
4793
4794         if (output_format & DIFF_FORMAT_NO_OUTPUT &&
4795             DIFF_OPT_TST(options, EXIT_WITH_STATUS) &&
4796             DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4797                 /*
4798                  * run diff_flush_patch for the exit status. setting
4799                  * options->file to /dev/null should be safe, because we
4800                  * aren't supposed to produce any output anyway.
4801                  */
4802                 if (options->close_file)
4803                         fclose(options->file);
4804                 options->file = xfopen("/dev/null", "w");
4805                 options->close_file = 1;
4806                 for (i = 0; i < q->nr; i++) {
4807                         struct diff_filepair *p = q->queue[i];
4808                         if (check_pair_status(p))
4809                                 diff_flush_patch(p, options);
4810                         if (options->found_changes)
4811                                 break;
4812                 }
4813         }
4814
4815         if (output_format & DIFF_FORMAT_PATCH) {
4816                 if (separator) {
4817                         fprintf(options->file, "%s%c",
4818                                 diff_line_prefix(options),
4819                                 options->line_termination);
4820                         if (options->stat_sep) {
4821                                 /* attach patch instead of inline */
4822                                 fputs(options->stat_sep, options->file);
4823                         }
4824                 }
4825
4826                 for (i = 0; i < q->nr; i++) {
4827                         struct diff_filepair *p = q->queue[i];
4828                         if (check_pair_status(p))
4829                                 diff_flush_patch(p, options);
4830                 }
4831         }
4832
4833         if (output_format & DIFF_FORMAT_CALLBACK)
4834                 options->format_callback(q, options, options->format_callback_data);
4835
4836         for (i = 0; i < q->nr; i++)
4837                 diff_free_filepair(q->queue[i]);
4838 free_queue:
4839         free(q->queue);
4840         DIFF_QUEUE_CLEAR(q);
4841         if (options->close_file)
4842                 fclose(options->file);
4843
4844         /*
4845          * Report the content-level differences with HAS_CHANGES;
4846          * diff_addremove/diff_change does not set the bit when
4847          * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
4848          */
4849         if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4850                 if (options->found_changes)
4851                         DIFF_OPT_SET(options, HAS_CHANGES);
4852                 else
4853                         DIFF_OPT_CLR(options, HAS_CHANGES);
4854         }
4855 }
4856
4857 static int match_filter(const struct diff_options *options, const struct diff_filepair *p)
4858 {
4859         return (((p->status == DIFF_STATUS_MODIFIED) &&
4860                  ((p->score &&
4861                    filter_bit_tst(DIFF_STATUS_FILTER_BROKEN, options)) ||
4862                   (!p->score &&
4863                    filter_bit_tst(DIFF_STATUS_MODIFIED, options)))) ||
4864                 ((p->status != DIFF_STATUS_MODIFIED) &&
4865                  filter_bit_tst(p->status, options)));
4866 }
4867
4868 static void diffcore_apply_filter(struct diff_options *options)
4869 {
4870         int i;
4871         struct diff_queue_struct *q = &diff_queued_diff;
4872         struct diff_queue_struct outq;
4873
4874         DIFF_QUEUE_CLEAR(&outq);
4875
4876         if (!options->filter)
4877                 return;
4878
4879         if (filter_bit_tst(DIFF_STATUS_FILTER_AON, options)) {
4880                 int found;
4881                 for (i = found = 0; !found && i < q->nr; i++) {
4882                         if (match_filter(options, q->queue[i]))
4883                                 found++;
4884                 }
4885                 if (found)
4886                         return;
4887
4888                 /* otherwise we will clear the whole queue
4889                  * by copying the empty outq at the end of this
4890                  * function, but first clear the current entries
4891                  * in the queue.
4892                  */
4893                 for (i = 0; i < q->nr; i++)
4894                         diff_free_filepair(q->queue[i]);
4895         }
4896         else {
4897                 /* Only the matching ones */
4898                 for (i = 0; i < q->nr; i++) {
4899                         struct diff_filepair *p = q->queue[i];
4900                         if (match_filter(options, p))
4901                                 diff_q(&outq, p);
4902                         else
4903                                 diff_free_filepair(p);
4904                 }
4905         }
4906         free(q->queue);
4907         *q = outq;
4908 }
4909
4910 /* Check whether two filespecs with the same mode and size are identical */
4911 static int diff_filespec_is_identical(struct diff_filespec *one,
4912                                       struct diff_filespec *two)
4913 {
4914         if (S_ISGITLINK(one->mode))
4915                 return 0;
4916         if (diff_populate_filespec(one, 0))
4917                 return 0;
4918         if (diff_populate_filespec(two, 0))
4919                 return 0;
4920         return !memcmp(one->data, two->data, one->size);
4921 }
4922
4923 static int diff_filespec_check_stat_unmatch(struct diff_filepair *p)
4924 {
4925         if (p->done_skip_stat_unmatch)
4926                 return p->skip_stat_unmatch_result;
4927
4928         p->done_skip_stat_unmatch = 1;
4929         p->skip_stat_unmatch_result = 0;
4930         /*
4931          * 1. Entries that come from stat info dirtiness
4932          *    always have both sides (iow, not create/delete),
4933          *    one side of the object name is unknown, with
4934          *    the same mode and size.  Keep the ones that
4935          *    do not match these criteria.  They have real
4936          *    differences.
4937          *
4938          * 2. At this point, the file is known to be modified,
4939          *    with the same mode and size, and the object
4940          *    name of one side is unknown.  Need to inspect
4941          *    the identical contents.
4942          */
4943         if (!DIFF_FILE_VALID(p->one) || /* (1) */
4944             !DIFF_FILE_VALID(p->two) ||
4945             (p->one->oid_valid && p->two->oid_valid) ||
4946             (p->one->mode != p->two->mode) ||
4947             diff_populate_filespec(p->one, CHECK_SIZE_ONLY) ||
4948             diff_populate_filespec(p->two, CHECK_SIZE_ONLY) ||
4949             (p->one->size != p->two->size) ||
4950             !diff_filespec_is_identical(p->one, p->two)) /* (2) */
4951                 p->skip_stat_unmatch_result = 1;
4952         return p->skip_stat_unmatch_result;
4953 }
4954
4955 static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
4956 {
4957         int i;
4958         struct diff_queue_struct *q = &diff_queued_diff;
4959         struct diff_queue_struct outq;
4960         DIFF_QUEUE_CLEAR(&outq);
4961
4962         for (i = 0; i < q->nr; i++) {
4963                 struct diff_filepair *p = q->queue[i];
4964
4965                 if (diff_filespec_check_stat_unmatch(p))
4966                         diff_q(&outq, p);
4967                 else {
4968                         /*
4969                          * The caller can subtract 1 from skip_stat_unmatch
4970                          * to determine how many paths were dirty only
4971                          * due to stat info mismatch.
4972                          */
4973                         if (!DIFF_OPT_TST(diffopt, NO_INDEX))
4974                                 diffopt->skip_stat_unmatch++;
4975                         diff_free_filepair(p);
4976                 }
4977         }
4978         free(q->queue);
4979         *q = outq;
4980 }
4981
4982 static int diffnamecmp(const void *a_, const void *b_)
4983 {
4984         const struct diff_filepair *a = *((const struct diff_filepair **)a_);
4985         const struct diff_filepair *b = *((const struct diff_filepair **)b_);
4986         const char *name_a, *name_b;
4987
4988         name_a = a->one ? a->one->path : a->two->path;
4989         name_b = b->one ? b->one->path : b->two->path;
4990         return strcmp(name_a, name_b);
4991 }
4992
4993 void diffcore_fix_diff_index(struct diff_options *options)
4994 {
4995         struct diff_queue_struct *q = &diff_queued_diff;
4996         QSORT(q->queue, q->nr, diffnamecmp);
4997 }
4998
4999 void diffcore_std(struct diff_options *options)
5000 {
5001         /* NOTE please keep the following in sync with diff_tree_combined() */
5002         if (options->skip_stat_unmatch)
5003                 diffcore_skip_stat_unmatch(options);
5004         if (!options->found_follow) {
5005                 /* See try_to_follow_renames() in tree-diff.c */
5006                 if (options->break_opt != -1)
5007                         diffcore_break(options->break_opt);
5008                 if (options->detect_rename)
5009                         diffcore_rename(options);
5010                 if (options->break_opt != -1)
5011                         diffcore_merge_broken();
5012         }
5013         if (options->pickaxe)
5014                 diffcore_pickaxe(options);
5015         if (options->orderfile)
5016                 diffcore_order(options->orderfile);
5017         if (!options->found_follow)
5018                 /* See try_to_follow_renames() in tree-diff.c */
5019                 diff_resolve_rename_copy();
5020         diffcore_apply_filter(options);
5021
5022         if (diff_queued_diff.nr && !DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
5023                 DIFF_OPT_SET(options, HAS_CHANGES);
5024         else
5025                 DIFF_OPT_CLR(options, HAS_CHANGES);
5026
5027         options->found_follow = 0;
5028 }
5029
5030 int diff_result_code(struct diff_options *opt, int status)
5031 {
5032         int result = 0;
5033
5034         diff_warn_rename_limit("diff.renameLimit",
5035                                opt->needed_rename_limit,
5036                                opt->degraded_cc_to_c);
5037         if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
5038             !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
5039                 return status;
5040         if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
5041             DIFF_OPT_TST(opt, HAS_CHANGES))
5042                 result |= 01;
5043         if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
5044             DIFF_OPT_TST(opt, CHECK_FAILED))
5045                 result |= 02;
5046         return result;
5047 }
5048
5049 int diff_can_quit_early(struct diff_options *opt)
5050 {
5051         return (DIFF_OPT_TST(opt, QUICK) &&
5052                 !opt->filter &&
5053                 DIFF_OPT_TST(opt, HAS_CHANGES));
5054 }
5055
5056 /*
5057  * Shall changes to this submodule be ignored?
5058  *
5059  * Submodule changes can be configured to be ignored separately for each path,
5060  * but that configuration can be overridden from the command line.
5061  */
5062 static int is_submodule_ignored(const char *path, struct diff_options *options)
5063 {
5064         int ignored = 0;
5065         unsigned orig_flags = options->flags;
5066         if (!DIFF_OPT_TST(options, OVERRIDE_SUBMODULE_CONFIG))
5067                 set_diffopt_flags_from_submodule_config(options, path);
5068         if (DIFF_OPT_TST(options, IGNORE_SUBMODULES))
5069                 ignored = 1;
5070         options->flags = orig_flags;
5071         return ignored;
5072 }
5073
5074 void diff_addremove(struct diff_options *options,
5075                     int addremove, unsigned mode,
5076                     const struct object_id *oid,
5077                     int oid_valid,
5078                     const char *concatpath, unsigned dirty_submodule)
5079 {
5080         struct diff_filespec *one, *two;
5081
5082         if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
5083                 return;
5084
5085         /* This may look odd, but it is a preparation for
5086          * feeding "there are unchanged files which should
5087          * not produce diffs, but when you are doing copy
5088          * detection you would need them, so here they are"
5089          * entries to the diff-core.  They will be prefixed
5090          * with something like '=' or '*' (I haven't decided
5091          * which but should not make any difference).
5092          * Feeding the same new and old to diff_change()
5093          * also has the same effect.
5094          * Before the final output happens, they are pruned after
5095          * merged into rename/copy pairs as appropriate.
5096          */
5097         if (DIFF_OPT_TST(options, REVERSE_DIFF))
5098                 addremove = (addremove == '+' ? '-' :
5099                              addremove == '-' ? '+' : addremove);
5100
5101         if (options->prefix &&
5102             strncmp(concatpath, options->prefix, options->prefix_length))
5103                 return;
5104
5105         one = alloc_filespec(concatpath);
5106         two = alloc_filespec(concatpath);
5107
5108         if (addremove != '+')
5109                 fill_filespec(one, oid, oid_valid, mode);
5110         if (addremove != '-') {
5111                 fill_filespec(two, oid, oid_valid, mode);
5112                 two->dirty_submodule = dirty_submodule;
5113         }
5114
5115         diff_queue(&diff_queued_diff, one, two);
5116         if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
5117                 DIFF_OPT_SET(options, HAS_CHANGES);
5118 }
5119
5120 void diff_change(struct diff_options *options,
5121                  unsigned old_mode, unsigned new_mode,
5122                  const struct object_id *old_oid,
5123                  const struct object_id *new_oid,
5124                  int old_oid_valid, int new_oid_valid,
5125                  const char *concatpath,
5126                  unsigned old_dirty_submodule, unsigned new_dirty_submodule)
5127 {
5128         struct diff_filespec *one, *two;
5129         struct diff_filepair *p;
5130
5131         if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
5132             is_submodule_ignored(concatpath, options))
5133                 return;
5134
5135         if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
5136                 SWAP(old_mode, new_mode);
5137                 SWAP(old_oid, new_oid);
5138                 SWAP(old_oid_valid, new_oid_valid);
5139                 SWAP(old_dirty_submodule, new_dirty_submodule);
5140         }
5141
5142         if (options->prefix &&
5143             strncmp(concatpath, options->prefix, options->prefix_length))
5144                 return;
5145
5146         one = alloc_filespec(concatpath);
5147         two = alloc_filespec(concatpath);
5148         fill_filespec(one, old_oid, old_oid_valid, old_mode);
5149         fill_filespec(two, new_oid, new_oid_valid, new_mode);
5150         one->dirty_submodule = old_dirty_submodule;
5151         two->dirty_submodule = new_dirty_submodule;
5152         p = diff_queue(&diff_queued_diff, one, two);
5153
5154         if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
5155                 return;
5156
5157         if (DIFF_OPT_TST(options, QUICK) && options->skip_stat_unmatch &&
5158             !diff_filespec_check_stat_unmatch(p))
5159                 return;
5160
5161         DIFF_OPT_SET(options, HAS_CHANGES);
5162 }
5163
5164 struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
5165 {
5166         struct diff_filepair *pair;
5167         struct diff_filespec *one, *two;
5168
5169         if (options->prefix &&
5170             strncmp(path, options->prefix, options->prefix_length))
5171                 return NULL;
5172
5173         one = alloc_filespec(path);
5174         two = alloc_filespec(path);
5175         pair = diff_queue(&diff_queued_diff, one, two);
5176         pair->is_unmerged = 1;
5177         return pair;
5178 }
5179
5180 static char *run_textconv(const char *pgm, struct diff_filespec *spec,
5181                 size_t *outsize)
5182 {
5183         struct diff_tempfile *temp;
5184         const char *argv[3];
5185         const char **arg = argv;
5186         struct child_process child = CHILD_PROCESS_INIT;
5187         struct strbuf buf = STRBUF_INIT;
5188         int err = 0;
5189
5190         temp = prepare_temp_file(spec->path, spec);
5191         *arg++ = pgm;
5192         *arg++ = temp->name;
5193         *arg = NULL;
5194
5195         child.use_shell = 1;
5196         child.argv = argv;
5197         child.out = -1;
5198         if (start_command(&child)) {
5199                 remove_tempfile();
5200                 return NULL;
5201         }
5202
5203         if (strbuf_read(&buf, child.out, 0) < 0)
5204                 err = error("error reading from textconv command '%s'", pgm);
5205         close(child.out);
5206
5207         if (finish_command(&child) || err) {
5208                 strbuf_release(&buf);
5209                 remove_tempfile();
5210                 return NULL;
5211         }
5212         remove_tempfile();
5213
5214         return strbuf_detach(&buf, outsize);
5215 }
5216
5217 size_t fill_textconv(struct userdiff_driver *driver,
5218                      struct diff_filespec *df,
5219                      char **outbuf)
5220 {
5221         size_t size;
5222
5223         if (!driver) {
5224                 if (!DIFF_FILE_VALID(df)) {
5225                         *outbuf = "";
5226                         return 0;
5227                 }
5228                 if (diff_populate_filespec(df, 0))
5229                         die("unable to read files to diff");
5230                 *outbuf = df->data;
5231                 return df->size;
5232         }
5233
5234         if (!driver->textconv)
5235                 die("BUG: fill_textconv called with non-textconv driver");
5236
5237         if (driver->textconv_cache && df->oid_valid) {
5238                 *outbuf = notes_cache_get(driver->textconv_cache,
5239                                           &df->oid,
5240                                           &size);
5241                 if (*outbuf)
5242                         return size;
5243         }
5244
5245         *outbuf = run_textconv(driver->textconv, df, &size);
5246         if (!*outbuf)
5247                 die("unable to read files to diff");
5248
5249         if (driver->textconv_cache && df->oid_valid) {
5250                 /* ignore errors, as we might be in a readonly repository */
5251                 notes_cache_put(driver->textconv_cache, &df->oid, *outbuf,
5252                                 size);
5253                 /*
5254                  * we could save up changes and flush them all at the end,
5255                  * but we would need an extra call after all diffing is done.
5256                  * Since generating a cache entry is the slow path anyway,
5257                  * this extra overhead probably isn't a big deal.
5258                  */
5259                 notes_cache_write(driver->textconv_cache);
5260         }
5261
5262         return size;
5263 }
5264
5265 int textconv_object(const char *path,
5266                     unsigned mode,
5267                     const struct object_id *oid,
5268                     int oid_valid,
5269                     char **buf,
5270                     unsigned long *buf_size)
5271 {
5272         struct diff_filespec *df;
5273         struct userdiff_driver *textconv;
5274
5275         df = alloc_filespec(path);
5276         fill_filespec(df, oid, oid_valid, mode);
5277         textconv = get_textconv(df);
5278         if (!textconv) {
5279                 free_filespec(df);
5280                 return 0;
5281         }
5282
5283         *buf_size = fill_textconv(textconv, df, buf);
5284         free_filespec(df);
5285         return 1;
5286 }
5287
5288 void setup_diff_pager(struct diff_options *opt)
5289 {
5290         /*
5291          * If the user asked for our exit code, then either they want --quiet
5292          * or --exit-code. We should definitely not bother with a pager in the
5293          * former case, as we will generate no output. Since we still properly
5294          * report our exit code even when a pager is run, we _could_ run a
5295          * pager with --exit-code. But since we have not done so historically,
5296          * and because it is easy to find people oneline advising "git diff
5297          * --exit-code" in hooks and other scripts, we do not do so.
5298          */
5299         if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
5300             check_pager_config("diff") != 0)
5301                 setup_pager();
5302 }