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