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         if (git_color_config(var, value, cb) < 0)
 303                 return -1;
 304
 305         return git_diff_basic_config(var, value, cb);
 306 }
 307
 308 int git_diff_basic_config(const char *var, const char *value, void *cb)
 309 {
 310         const char *name;
 311
 312         if (!strcmp(var, "diff.renamelimit")) {
 313                 diff_rename_limit_default = git_config_int(var, value);
 314                 return 0;
 315         }
 316
 317         if (userdiff_config(var, value) < 0)
 318                 return -1;
 319
 320         if (skip_prefix(var, "diff.color.", &name) ||
 321             skip_prefix(var, "color.diff.", &name)) {
 322                 int slot = parse_diff_color_slot(name);
 323                 if (slot < 0)
 324                         return 0;
 325                 if (!value)
 326                         return config_error_nonbool(var);
 327                 return color_parse(value, diff_colors[slot]);
 328         }
 329
 330         /* like GNU diff's --suppress-blank-empty option  */
 331         if (!strcmp(var, "diff.suppressblankempty") ||
 332                         /* for backwards compatibility */
 333                         !strcmp(var, "diff.suppress-blank-empty")) {
 334                 diff_suppress_blank_empty = git_config_bool(var, value);
 335                 return 0;
 336         }
 337
 338         if (!strcmp(var, "diff.dirstat")) {
 339                 struct strbuf errmsg = STRBUF_INIT;
 340                 default_diff_options.dirstat_permille = diff_dirstat_permille_default;
 341                 if (parse_dirstat_params(&default_diff_options, value, &errmsg))
 342                         warning(_("Found errors in 'diff.dirstat' config variable:\n%s"),
 343                                 errmsg.buf);
 344                 strbuf_release(&errmsg);
 345                 diff_dirstat_permille_default = default_diff_options.dirstat_permille;
 346                 return 0;
 347         }
 348
 349         if (starts_with(var, "submodule."))
 350                 return parse_submodule_config_option(var, value);
 351
 352         if (git_diff_heuristic_config(var, value, cb) < 0)
 353                 return -1;
 354
 355         return git_default_config(var, value, cb);
 356 }
 357
 358 static char *quote_two(const char *one, const char *two)
 359 {
 360         int need_one = quote_c_style(one, NULL, NULL, 1);
 361         int need_two = quote_c_style(two, NULL, NULL, 1);
 362         struct strbuf res = STRBUF_INIT;
 363
 364         if (need_one + need_two) {
 365                 strbuf_addch(&res, '"');
 366                 quote_c_style(one, &res, NULL, 1);
 367                 quote_c_style(two, &res, NULL, 1);
 368                 strbuf_addch(&res, '"');
 369         } else {
 370                 strbuf_addstr(&res, one);
 371                 strbuf_addstr(&res, two);
 372         }
 373         return strbuf_detach(&res, NULL);
 374 }
 375
 376 static const char *external_diff(void)
 377 {
 378         static const char *external_diff_cmd = NULL;
 379         static int done_preparing = 0;
 380
 381         if (done_preparing)
 382                 return external_diff_cmd;
 383         external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 384         if (!external_diff_cmd)
 385                 external_diff_cmd = external_diff_cmd_cfg;
 386         done_preparing = 1;
 387         return external_diff_cmd;
 388 }
 389
 390 /*
 391  * Keep track of files used for diffing. Sometimes such an entry
 392  * refers to a temporary file, sometimes to an existing file, and
 393  * sometimes to "/dev/null".
 394  */
 395 static struct diff_tempfile {
 396         /*
 397          * filename external diff should read from, or NULL if this
 398          * entry is currently not in use:
 399          */
 400         const char *name;
 401
 402         char hex[GIT_MAX_HEXSZ + 1];
 403         char mode[10];
 404
 405         /*
 406          * If this diff_tempfile instance refers to a temporary file,
 407          * this tempfile object is used to manage its lifetime.
 408          */
 409         struct tempfile tempfile;
 410 } diff_temp[2];
 411
 412 typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
 413
 414 struct emit_callback {
 415         int color_diff;
 416         unsigned ws_rule;
 417         int blank_at_eof_in_preimage;
 418         int blank_at_eof_in_postimage;
 419         int lno_in_preimage;
 420         int lno_in_postimage;
 421         sane_truncate_fn truncate;
 422         const char **label_path;
 423         struct diff_words_data *diff_words;
 424         struct diff_options *opt;
 425         struct strbuf *header;
 426 };
 427
 428 static int count_lines(const char *data, int size)
 429 {
 430         int count, ch, completely_empty = 1, nl_just_seen = 0;
 431         count = 0;
 432         while (0 < size--) {
 433                 ch = *data++;
 434                 if (ch == '\n') {
 435                         count++;
 436                         nl_just_seen = 1;
 437                         completely_empty = 0;
 438                 }
 439                 else {
 440                         nl_just_seen = 0;
 441                         completely_empty = 0;
 442                 }
 443         }
 444         if (completely_empty)
 445                 return 0;
 446         if (!nl_just_seen)
 447                 count++; /* no trailing newline */
 448         return count;
 449 }
 450
 451 static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 452 {
 453         if (!DIFF_FILE_VALID(one)) {
 454                 mf->ptr = (char *)""; /* does not matter */
 455                 mf->size = 0;
 456                 return 0;
 457         }
 458         else if (diff_populate_filespec(one, 0))
 459                 return -1;
 460
 461         mf->ptr = one->data;
 462         mf->size = one->size;
 463         return 0;
 464 }
 465
 466 /* like fill_mmfile, but only for size, so we can avoid retrieving blob */
 467 static unsigned long diff_filespec_size(struct diff_filespec *one)
 468 {
 469         if (!DIFF_FILE_VALID(one))
 470                 return 0;
 471         diff_populate_filespec(one, CHECK_SIZE_ONLY);
 472         return one->size;
 473 }
 474
 475 static int count_trailing_blank(mmfile_t *mf, unsigned ws_rule)
 476 {
 477         char *ptr = mf->ptr;
 478         long size = mf->size;
 479         int cnt = 0;
 480
 481         if (!size)
 482                 return cnt;
 483         ptr += size - 1; /* pointing at the very end */
 484         if (*ptr != '\n')
 485                 ; /* incomplete line */
 486         else
 487                 ptr--; /* skip the last LF */
 488         while (mf->ptr < ptr) {
 489                 char *prev_eol;
 490                 for (prev_eol = ptr; mf->ptr <= prev_eol; prev_eol--)
 491                         if (*prev_eol == '\n')
 492                                 break;
 493                 if (!ws_blank_line(prev_eol + 1, ptr - prev_eol, ws_rule))
 494                         break;
 495                 cnt++;
 496                 ptr = prev_eol - 1;
 497         }
 498         return cnt;
 499 }
 500
 501 static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
 502                                struct emit_callback *ecbdata)
 503 {
 504         int l1, l2, at;
 505         unsigned ws_rule = ecbdata->ws_rule;
 506         l1 = count_trailing_blank(mf1, ws_rule);
 507         l2 = count_trailing_blank(mf2, ws_rule);
 508         if (l2 <= l1) {
 509                 ecbdata->blank_at_eof_in_preimage = 0;
 510                 ecbdata->blank_at_eof_in_postimage = 0;
 511                 return;
 512         }
 513         at = count_lines(mf1->ptr, mf1->size);
 514         ecbdata->blank_at_eof_in_preimage = (at - l1) + 1;
 515
 516         at = count_lines(mf2->ptr, mf2->size);
 517         ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
 518 }
 519
 520 static void emit_line_0(struct diff_options *o, const char *set, const char *reset,
 521                         int first, const char *line, int len)
 522 {
 523         int has_trailing_newline, has_trailing_carriage_return;
 524         int nofirst;
 525         FILE *file = o->file;
 526
 527         fputs(diff_line_prefix(o), file);
 528
 529         if (len == 0) {
 530                 has_trailing_newline = (first == '\n');
 531                 has_trailing_carriage_return = (!has_trailing_newline &&
 532                                                 (first == '\r'));
 533                 nofirst = has_trailing_newline || has_trailing_carriage_return;
 534         } else {
 535                 has_trailing_newline = (len > 0 && line[len-1] == '\n');
 536                 if (has_trailing_newline)
 537                         len--;
 538                 has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
 539                 if (has_trailing_carriage_return)
 540                         len--;
 541                 nofirst = 0;
 542         }
 543
 544         if (len || !nofirst) {
 545                 fputs(set, file);
 546                 if (!nofirst)
 547                         fputc(first, file);
 548                 fwrite(line, len, 1, file);
 549                 fputs(reset, file);
 550         }
 551         if (has_trailing_carriage_return)
 552                 fputc('\r', file);
 553         if (has_trailing_newline)
 554                 fputc('\n', file);
 555 }
 556
 557 static void emit_line(struct diff_options *o, const char *set, const char *reset,
 558                       const char *line, int len)
 559 {
 560         emit_line_0(o, set, reset, line[0], line+1, len-1);
 561 }
 562
 563 static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
 564 {
 565         if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
 566               ecbdata->blank_at_eof_in_preimage &&
 567               ecbdata->blank_at_eof_in_postimage &&
 568               ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
 569               ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
 570                 return 0;
 571         return ws_blank_line(line, len, ecbdata->ws_rule);
 572 }
 573
 574 static void emit_line_checked(const char *reset,
 575                               struct emit_callback *ecbdata,
 576                               const char *line, int len,
 577                               enum color_diff color,
 578                               unsigned ws_error_highlight,
 579                               char sign)
 580 {
 581         const char *set = diff_get_color(ecbdata->color_diff, color);
 582         const char *ws = NULL;
 583
 584         if (ecbdata->opt->ws_error_highlight & ws_error_highlight) {
 585                 ws = diff_get_color(ecbdata->color_diff, DIFF_WHITESPACE);
 586                 if (!*ws)
 587                         ws = NULL;
 588         }
 589
 590         if (!ws)
 591                 emit_line_0(ecbdata->opt, set, reset, sign, line, len);
 592         else if (sign == '+' && new_blank_line_at_eof(ecbdata, line, len))
 593                 /* Blank line at EOF - paint '+' as well */
 594                 emit_line_0(ecbdata->opt, ws, reset, sign, line, len);
 595         else {
 596                 /* Emit just the prefix, then the rest. */
 597                 emit_line_0(ecbdata->opt, set, reset, sign, "", 0);
 598                 ws_check_emit(line, len, ecbdata->ws_rule,
 599                               ecbdata->opt->file, set, reset, ws);
 600         }
 601 }
 602
 603 static void emit_add_line(const char *reset,
 604                           struct emit_callback *ecbdata,
 605                           const char *line, int len)
 606 {
 607         emit_line_checked(reset, ecbdata, line, len,
 608                           DIFF_FILE_NEW, WSEH_NEW, '+');
 609 }
 610
 611 static void emit_del_line(const char *reset,
 612                           struct emit_callback *ecbdata,
 613                           const char *line, int len)
 614 {
 615         emit_line_checked(reset, ecbdata, line, len,
 616                           DIFF_FILE_OLD, WSEH_OLD, '-');
 617 }
 618
 619 static void emit_context_line(const char *reset,
 620                               struct emit_callback *ecbdata,
 621                               const char *line, int len)
 622 {
 623         emit_line_checked(reset, ecbdata, line, len,
 624                           DIFF_CONTEXT, WSEH_CONTEXT, ' ');
 625 }
 626
 627 static void emit_hunk_header(struct emit_callback *ecbdata,
 628                              const char *line, int len)
 629 {
 630         const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
 631         const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
 632         const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
 633         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
 634         static const char atat[2] = { '@', '@' };
 635         const char *cp, *ep;
 636         struct strbuf msgbuf = STRBUF_INIT;
 637         int org_len = len;
 638         int i = 1;
 639
 640         /*
 641          * As a hunk header must begin with "@@ -<old>, +<new> @@",
 642          * it always is at least 10 bytes long.
 643          */
 644         if (len < 10 ||
 645             memcmp(line, atat, 2) ||
 646             !(ep = memmem(line + 2, len - 2, atat, 2))) {
 647                 emit_line(ecbdata->opt, context, reset, line, len);
 648                 return;
 649         }
 650         ep += 2; /* skip over @@ */
 651
 652         /* The hunk header in fraginfo color */
 653         strbuf_addstr(&msgbuf, frag);
 654         strbuf_add(&msgbuf, line, ep - line);
 655         strbuf_addstr(&msgbuf, reset);
 656
 657         /*
 658          * trailing "\r\n"
 659          */
 660         for ( ; i < 3; i++)
 661                 if (line[len - i] == '\r' || line[len - i] == '\n')
 662                         len--;
 663
 664         /* blank before the func header */
 665         for (cp = ep; ep - line < len; ep++)
 666                 if (*ep != ' ' && *ep != '\t')
 667                         break;
 668         if (ep != cp) {
 669                 strbuf_addstr(&msgbuf, context);
 670                 strbuf_add(&msgbuf, cp, ep - cp);
 671                 strbuf_addstr(&msgbuf, reset);
 672         }
 673
 674         if (ep < line + len) {
 675                 strbuf_addstr(&msgbuf, func);
 676                 strbuf_add(&msgbuf, ep, line + len - ep);
 677                 strbuf_addstr(&msgbuf, reset);
 678         }
 679
 680         strbuf_add(&msgbuf, line + len, org_len - len);
 681         emit_line(ecbdata->opt, "", "", msgbuf.buf, msgbuf.len);
 682         strbuf_release(&msgbuf);
 683 }
 684
 685 static struct diff_tempfile *claim_diff_tempfile(void) {
 686         int i;
 687         for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
 688                 if (!diff_temp[i].name)
 689                         return diff_temp + i;
 690         die("BUG: diff is failing to clean up its tempfiles");
 691 }
 692
 693 static void remove_tempfile(void)
 694 {
 695         int i;
 696         for (i = 0; i < ARRAY_SIZE(diff_temp); i++) {
 697                 if (is_tempfile_active(&diff_temp[i].tempfile))
 698                         delete_tempfile(&diff_temp[i].tempfile);
 699                 diff_temp[i].name = NULL;
 700         }
 701 }
 702
 703 static void print_line_count(FILE *file, int count)
 704 {
 705         switch (count) {
 706         case 0:
 707                 fprintf(file, "0,0");
 708                 break;
 709         case 1:
 710                 fprintf(file, "1");
 711                 break;
 712         default:
 713                 fprintf(file, "1,%d", count);
 714                 break;
 715         }
 716 }
 717
 718 static void emit_rewrite_lines(struct emit_callback *ecb,
 719                                int prefix, const char *data, int size)
 720 {
 721         const char *endp = NULL;
 722         static const char *nneof = " No newline at end of file\n";
 723         const char *reset = diff_get_color(ecb->color_diff, DIFF_RESET);
 724
 725         while (0 < size) {
 726                 int len;
 727
 728                 endp = memchr(data, '\n', size);
 729                 len = endp ? (endp - data + 1) : size;
 730                 if (prefix != '+') {
 731                         ecb->lno_in_preimage++;
 732                         emit_del_line(reset, ecb, data, len);
 733                 } else {
 734                         ecb->lno_in_postimage++;
 735                         emit_add_line(reset, ecb, data, len);
 736                 }
 737                 size -= len;
 738                 data += len;
 739         }
 740         if (!endp) {
 741                 const char *context = diff_get_color(ecb->color_diff,
 742                                                      DIFF_CONTEXT);
 743                 putc('\n', ecb->opt->file);
 744                 emit_line_0(ecb->opt, context, reset, '\\',
 745                             nneof, strlen(nneof));
 746         }
 747 }
 748
 749 static void emit_rewrite_diff(const char *name_a,
 750                               const char *name_b,
 751                               struct diff_filespec *one,
 752                               struct diff_filespec *two,
 753                               struct userdiff_driver *textconv_one,
 754                               struct userdiff_driver *textconv_two,
 755                               struct diff_options *o)
 756 {
 757         int lc_a, lc_b;
 758         const char *name_a_tab, *name_b_tab;
 759         const char *metainfo = diff_get_color(o->use_color, DIFF_METAINFO);
 760         const char *fraginfo = diff_get_color(o->use_color, DIFF_FRAGINFO);
 761         const char *reset = diff_get_color(o->use_color, DIFF_RESET);
 762         static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
 763         const char *a_prefix, *b_prefix;
 764         char *data_one, *data_two;
 765         size_t size_one, size_two;
 766         struct emit_callback ecbdata;
 767         const char *line_prefix = diff_line_prefix(o);
 768
 769         if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
 770                 a_prefix = o->b_prefix;
 771                 b_prefix = o->a_prefix;
 772         } else {
 773                 a_prefix = o->a_prefix;
 774                 b_prefix = o->b_prefix;
 775         }
 776
 777         name_a += (*name_a == '/');
 778         name_b += (*name_b == '/');
 779         name_a_tab = strchr(name_a, ' ') ? "\t" : "";
 780         name_b_tab = strchr(name_b, ' ') ? "\t" : "";
 781
 782         strbuf_reset(&a_name);
 783         strbuf_reset(&b_name);
 784         quote_two_c_style(&a_name, a_prefix, name_a, 0);
 785         quote_two_c_style(&b_name, b_prefix, name_b, 0);
 786
 787         size_one = fill_textconv(textconv_one, one, &data_one);
 788         size_two = fill_textconv(textconv_two, two, &data_two);
 789
 790         memset(&ecbdata, 0, sizeof(ecbdata));
 791         ecbdata.color_diff = want_color(o->use_color);
 792         ecbdata.ws_rule = whitespace_rule(name_b);
 793         ecbdata.opt = o;
 794         if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
 795                 mmfile_t mf1, mf2;
 796                 mf1.ptr = (char *)data_one;
 797                 mf2.ptr = (char *)data_two;
 798                 mf1.size = size_one;
 799                 mf2.size = size_two;
 800                 check_blank_at_eof(&mf1, &mf2, &ecbdata);
 801         }
 802         ecbdata.lno_in_preimage = 1;
 803         ecbdata.lno_in_postimage = 1;
 804
 805         lc_a = count_lines(data_one, size_one);
 806         lc_b = count_lines(data_two, size_two);
 807         fprintf(o->file,
 808                 "%s%s--- %s%s%s\n%s%s+++ %s%s%s\n%s%s@@ -",
 809                 line_prefix, metainfo, a_name.buf, name_a_tab, reset,
 810                 line_prefix, metainfo, b_name.buf, name_b_tab, reset,
 811                 line_prefix, fraginfo);
 812         if (!o->irreversible_delete)
 813                 print_line_count(o->file, lc_a);
 814         else
 815                 fprintf(o->file, "?,?");
 816         fprintf(o->file, " +");
 817         print_line_count(o->file, lc_b);
 818         fprintf(o->file, " @@%s\n", reset);
 819         if (lc_a && !o->irreversible_delete)
 820                 emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
 821         if (lc_b)
 822                 emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
 823         if (textconv_one)
 824                 free((char *)data_one);
 825         if (textconv_two)
 826                 free((char *)data_two);
 827 }
 828
 829 struct diff_words_buffer {
 830         mmfile_t text;
 831         long alloc;
 832         struct diff_words_orig {
 833                 const char *begin, *end;
 834         } *orig;
 835         int orig_nr, orig_alloc;
 836 };
 837
 838 static void diff_words_append(char *line, unsigned long len,
 839                 struct diff_words_buffer *buffer)
 840 {
 841         ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
 842         line++;
 843         len--;
 844         memcpy(buffer->text.ptr + buffer->text.size, line, len);
 845         buffer->text.size += len;
 846         buffer->text.ptr[buffer->text.size] = '\0';
 847 }
 848
 849 struct diff_words_style_elem {
 850         const char *prefix;
 851         const char *suffix;
 852         const char *color; /* NULL; filled in by the setup code if
 853                             * color is enabled */
 854 };
 855
 856 struct diff_words_style {
 857         enum diff_words_type type;
 858         struct diff_words_style_elem new, old, ctx;
 859         const char *newline;
 860 };
 861
 862 static struct diff_words_style diff_words_styles[] = {
 863         { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
 864         { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
 865         { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
 866 };
 867
 868 struct diff_words_data {
 869         struct diff_words_buffer minus, plus;
 870         const char *current_plus;
 871         int last_minus;
 872         struct diff_options *opt;
 873         regex_t *word_regex;
 874         enum diff_words_type type;
 875         struct diff_words_style *style;
 876 };
 877
 878 static int fn_out_diff_words_write_helper(FILE *fp,
 879                                           struct diff_words_style_elem *st_el,
 880                                           const char *newline,
 881                                           size_t count, const char *buf,
 882                                           const char *line_prefix)
 883 {
 884         int print = 0;
 885
 886         while (count) {
 887                 char *p = memchr(buf, '\n', count);
 888                 if (print)
 889                         fputs(line_prefix, fp);
 890                 if (p != buf) {
 891                         if (st_el->color && fputs(st_el->color, fp) < 0)
 892                                 return -1;
 893                         if (fputs(st_el->prefix, fp) < 0 ||
 894                             fwrite(buf, p ? p - buf : count, 1, fp) != 1 ||
 895                             fputs(st_el->suffix, fp) < 0)
 896                                 return -1;
 897                         if (st_el->color && *st_el->color
 898                             && fputs(GIT_COLOR_RESET, fp) < 0)
 899                                 return -1;
 900                 }
 901                 if (!p)
 902                         return 0;
 903                 if (fputs(newline, fp) < 0)
 904                         return -1;
 905                 count -= p + 1 - buf;
 906                 buf = p + 1;
 907                 print = 1;
 908         }
 909         return 0;
 910 }
 911
 912 /*
 913  * '--color-words' algorithm can be described as:
 914  *
 915  *   1. collect the minus/plus lines of a diff hunk, divided into
 916  *      minus-lines and plus-lines;
 917  *
 918  *   2. break both minus-lines and plus-lines into words and
 919  *      place them into two mmfile_t with one word for each line;
 920  *
 921  *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
 922  *
 923  * And for the common parts of the both file, we output the plus side text.
 924  * diff_words->current_plus is used to trace the current position of the plus file
 925  * which printed. diff_words->last_minus is used to trace the last minus word
 926  * printed.
 927  *
 928  * For '--graph' to work with '--color-words', we need to output the graph prefix
 929  * on each line of color words output. Generally, there are two conditions on
 930  * which we should output the prefix.
 931  *
 932  *   1. diff_words->last_minus == 0 &&
 933  *      diff_words->current_plus == diff_words->plus.text.ptr
 934  *
 935  *      that is: the plus text must start as a new line, and if there is no minus
 936  *      word printed, a graph prefix must be printed.
 937  *
 938  *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
 939  *      *(diff_words->current_plus - 1) == '\n'
 940  *
 941  *      that is: a graph prefix must be printed following a '\n'
 942  */
 943 static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
 944 {
 945         if ((diff_words->last_minus == 0 &&
 946                 diff_words->current_plus == diff_words->plus.text.ptr) ||
 947                 (diff_words->current_plus > diff_words->plus.text.ptr &&
 948                 *(diff_words->current_plus - 1) == '\n')) {
 949                 return 1;
 950         } else {
 951                 return 0;
 952         }
 953 }
 954
 955 static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
 956 {
 957         struct diff_words_data *diff_words = priv;
 958         struct diff_words_style *style = diff_words->style;
 959         int minus_first, minus_len, plus_first, plus_len;
 960         const char *minus_begin, *minus_end, *plus_begin, *plus_end;
 961         struct diff_options *opt = diff_words->opt;
 962         const char *line_prefix;
 963
 964         if (line[0] != '@' || parse_hunk_header(line, len,
 965                         &minus_first, &minus_len, &plus_first, &plus_len))
 966                 return;
 967
 968         assert(opt);
 969         line_prefix = diff_line_prefix(opt);
 970
 971         /* POSIX requires that first be decremented by one if len == 0... */
 972         if (minus_len) {
 973                 minus_begin = diff_words->minus.orig[minus_first].begin;
 974                 minus_end =
 975                         diff_words->minus.orig[minus_first + minus_len - 1].end;
 976         } else
 977                 minus_begin = minus_end =
 978                         diff_words->minus.orig[minus_first].end;
 979
 980         if (plus_len) {
 981                 plus_begin = diff_words->plus.orig[plus_first].begin;
 982                 plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
 983         } else
 984                 plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
 985
 986         if (color_words_output_graph_prefix(diff_words)) {
 987                 fputs(line_prefix, diff_words->opt->file);
 988         }
 989         if (diff_words->current_plus != plus_begin) {
 990                 fn_out_diff_words_write_helper(diff_words->opt->file,
 991                                 &style->ctx, style->newline,
 992                                 plus_begin - diff_words->current_plus,
 993                                 diff_words->current_plus, line_prefix);
 994                 if (*(plus_begin - 1) == '\n')
 995                         fputs(line_prefix, diff_words->opt->file);
 996         }
 997         if (minus_begin != minus_end) {
 998                 fn_out_diff_words_write_helper(diff_words->opt->file,
 999                                 &style->old, style->newline,
1000                                 minus_end - minus_begin, minus_begin,
1001                                 line_prefix);
1002         }
1003         if (plus_begin != plus_end) {
1004                 fn_out_diff_words_write_helper(diff_words->opt->file,
1005                                 &style->new, style->newline,
1006                                 plus_end - plus_begin, plus_begin,
1007                                 line_prefix);
1008         }
1009
1010         diff_words->current_plus = plus_end;
1011         diff_words->last_minus = minus_first;
1012 }
1013
1014 /* This function starts looking at *begin, and returns 0 iff a word was found. */
1015 static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
1016                 int *begin, int *end)
1017 {
1018         if (word_regex && *begin < buffer->size) {
1019                 regmatch_t match[1];
1020                 if (!regexec_buf(word_regex, buffer->ptr + *begin,
1021                                  buffer->size - *begin, 1, match, 0)) {
1022                         char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
1023                                         '\n', match[0].rm_eo - match[0].rm_so);
1024                         *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
1025                         *begin += match[0].rm_so;
1026                         return *begin >= *end;
1027                 }
1028                 return -1;
1029         }
1030
1031         /* find the next word */
1032         while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
1033                 (*begin)++;
1034         if (*begin >= buffer->size)
1035                 return -1;
1036
1037         /* find the end of the word */
1038         *end = *begin + 1;
1039         while (*end < buffer->size && !isspace(buffer->ptr[*end]))
1040                 (*end)++;
1041
1042         return 0;
1043 }
1044
1045 /*
1046  * This function splits the words in buffer->text, stores the list with
1047  * newline separator into out, and saves the offsets of the original words
1048  * in buffer->orig.
1049  */
1050 static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
1051                 regex_t *word_regex)
1052 {
1053         int i, j;
1054         long alloc = 0;
1055
1056         out->size = 0;
1057         out->ptr = NULL;
1058
1059         /* fake an empty "0th" word */
1060         ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
1061         buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
1062         buffer->orig_nr = 1;
1063
1064         for (i = 0; i < buffer->text.size; i++) {
1065                 if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
1066                         return;
1067
1068                 /* store original boundaries */
1069                 ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
1070                                 buffer->orig_alloc);
1071                 buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
1072                 buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
1073                 buffer->orig_nr++;
1074
1075                 /* store one word */
1076                 ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
1077                 memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
1078                 out->ptr[out->size + j - i] = '\n';
1079                 out->size += j - i + 1;
1080
1081                 i = j - 1;
1082         }
1083 }
1084
1085 /* this executes the word diff on the accumulated buffers */
1086 static void diff_words_show(struct diff_words_data *diff_words)
1087 {
1088         xpparam_t xpp;
1089         xdemitconf_t xecfg;
1090         mmfile_t minus, plus;
1091         struct diff_words_style *style = diff_words->style;
1092
1093         struct diff_options *opt = diff_words->opt;
1094         const char *line_prefix;
1095
1096         assert(opt);
1097         line_prefix = diff_line_prefix(opt);
1098
1099         /* special case: only removal */
1100         if (!diff_words->plus.text.size) {
1101                 fputs(line_prefix, diff_words->opt->file);
1102                 fn_out_diff_words_write_helper(diff_words->opt->file,
1103                         &style->old, style->newline,
1104                         diff_words->minus.text.size,
1105                         diff_words->minus.text.ptr, line_prefix);
1106                 diff_words->minus.text.size = 0;
1107                 return;
1108         }
1109
1110         diff_words->current_plus = diff_words->plus.text.ptr;
1111         diff_words->last_minus = 0;
1112
1113         memset(&xpp, 0, sizeof(xpp));
1114         memset(&xecfg, 0, sizeof(xecfg));
1115         diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
1116         diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
1117         xpp.flags = 0;
1118         /* as only the hunk header will be parsed, we need a 0-context */
1119         xecfg.ctxlen = 0;
1120         if (xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
1121                           &xpp, &xecfg))
1122                 die("unable to generate word diff");
1123         free(minus.ptr);
1124         free(plus.ptr);
1125         if (diff_words->current_plus != diff_words->plus.text.ptr +
1126                         diff_words->plus.text.size) {
1127                 if (color_words_output_graph_prefix(diff_words))
1128                         fputs(line_prefix, diff_words->opt->file);
1129                 fn_out_diff_words_write_helper(diff_words->opt->file,
1130                         &style->ctx, style->newline,
1131                         diff_words->plus.text.ptr + diff_words->plus.text.size
1132                         - diff_words->current_plus, diff_words->current_plus,
1133                         line_prefix);
1134         }
1135         diff_words->minus.text.size = diff_words->plus.text.size = 0;
1136 }
1137
1138 /* In "color-words" mode, show word-diff of words accumulated in the buffer */
1139 static void diff_words_flush(struct emit_callback *ecbdata)
1140 {
1141         if (ecbdata->diff_words->minus.text.size ||
1142             ecbdata->diff_words->plus.text.size)
1143                 diff_words_show(ecbdata->diff_words);
1144 }
1145
1146 static void diff_filespec_load_driver(struct diff_filespec *one)
1147 {
1148         /* Use already-loaded driver */
1149         if (one->driver)
1150                 return;
1151
1152         if (S_ISREG(one->mode))
1153                 one->driver = userdiff_find_by_path(one->path);
1154
1155         /* Fallback to default settings */
1156         if (!one->driver)
1157                 one->driver = userdiff_find_by_name("default");
1158 }
1159
1160 static const char *userdiff_word_regex(struct diff_filespec *one)
1161 {
1162         diff_filespec_load_driver(one);
1163         return one->driver->word_regex;
1164 }
1165
1166 static void init_diff_words_data(struct emit_callback *ecbdata,
1167                                  struct diff_options *orig_opts,
1168                                  struct diff_filespec *one,
1169                                  struct diff_filespec *two)
1170 {
1171         int i;
1172         struct diff_options *o = xmalloc(sizeof(struct diff_options));
1173         memcpy(o, orig_opts, sizeof(struct diff_options));
1174
1175         ecbdata->diff_words =
1176                 xcalloc(1, sizeof(struct diff_words_data));
1177         ecbdata->diff_words->type = o->word_diff;
1178         ecbdata->diff_words->opt = o;
1179         if (!o->word_regex)
1180                 o->word_regex = userdiff_word_regex(one);
1181         if (!o->word_regex)
1182                 o->word_regex = userdiff_word_regex(two);
1183         if (!o->word_regex)
1184                 o->word_regex = diff_word_regex_cfg;
1185         if (o->word_regex) {
1186                 ecbdata->diff_words->word_regex = (regex_t *)
1187                         xmalloc(sizeof(regex_t));
1188                 if (regcomp(ecbdata->diff_words->word_regex,
1189                             o->word_regex,
1190                             REG_EXTENDED | REG_NEWLINE))
1191                         die ("Invalid regular expression: %s",
1192                              o->word_regex);
1193         }
1194         for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
1195                 if (o->word_diff == diff_words_styles[i].type) {
1196                         ecbdata->diff_words->style =
1197                                 &diff_words_styles[i];
1198                         break;
1199                 }
1200         }
1201         if (want_color(o->use_color)) {
1202                 struct diff_words_style *st = ecbdata->diff_words->style;
1203                 st->old.color = diff_get_color_opt(o, DIFF_FILE_OLD);
1204                 st->new.color = diff_get_color_opt(o, DIFF_FILE_NEW);
1205                 st->ctx.color = diff_get_color_opt(o, DIFF_CONTEXT);
1206         }
1207 }
1208
1209 static void free_diff_words_data(struct emit_callback *ecbdata)
1210 {
1211         if (ecbdata->diff_words) {
1212                 diff_words_flush(ecbdata);
1213                 free (ecbdata->diff_words->opt);
1214                 free (ecbdata->diff_words->minus.text.ptr);
1215                 free (ecbdata->diff_words->minus.orig);
1216                 free (ecbdata->diff_words->plus.text.ptr);
1217                 free (ecbdata->diff_words->plus.orig);
1218                 if (ecbdata->diff_words->word_regex) {
1219                         regfree(ecbdata->diff_words->word_regex);
1220                         free(ecbdata->diff_words->word_regex);
1221                 }
1222                 free(ecbdata->diff_words);
1223                 ecbdata->diff_words = NULL;
1224         }
1225 }
1226
1227 const char *diff_get_color(int diff_use_color, enum color_diff ix)
1228 {
1229         if (want_color(diff_use_color))
1230                 return diff_colors[ix];
1231         return "";
1232 }
1233
1234 const char *diff_line_prefix(struct diff_options *opt)
1235 {
1236         struct strbuf *msgbuf;
1237         if (!opt->output_prefix)
1238                 return "";
1239
1240         msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
1241         return msgbuf->buf;
1242 }
1243
1244 static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
1245 {
1246         const char *cp;
1247         unsigned long allot;
1248         size_t l = len;
1249
1250         if (ecb->truncate)
1251                 return ecb->truncate(line, len);
1252         cp = line;
1253         allot = l;
1254         while (0 < l) {
1255                 (void) utf8_width(&cp, &l);
1256                 if (!cp)
1257                         break; /* truncated in the middle? */
1258         }
1259         return allot - l;
1260 }
1261
1262 static void find_lno(const char *line, struct emit_callback *ecbdata)
1263 {
1264         const char *p;
1265         ecbdata->lno_in_preimage = 0;
1266         ecbdata->lno_in_postimage = 0;
1267         p = strchr(line, '-');
1268         if (!p)
1269                 return; /* cannot happen */
1270         ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
1271         p = strchr(p, '+');
1272         if (!p)
1273                 return; /* cannot happen */
1274         ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
1275 }
1276
1277 static void fn_out_consume(void *priv, char *line, unsigned long len)
1278 {
1279         struct emit_callback *ecbdata = priv;
1280         const char *meta = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
1281         const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
1282         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1283         struct diff_options *o = ecbdata->opt;
1284         const char *line_prefix = diff_line_prefix(o);
1285
1286         o->found_changes = 1;
1287
1288         if (ecbdata->header) {
1289                 fprintf(o->file, "%s", ecbdata->header->buf);
1290                 strbuf_reset(ecbdata->header);
1291                 ecbdata->header = NULL;
1292         }
1293
1294         if (ecbdata->label_path[0]) {
1295                 const char *name_a_tab, *name_b_tab;
1296
1297                 name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
1298                 name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
1299
1300                 fprintf(o->file, "%s%s--- %s%s%s\n",
1301                         line_prefix, meta, ecbdata->label_path[0], reset, name_a_tab);
1302                 fprintf(o->file, "%s%s+++ %s%s%s\n",
1303                         line_prefix, meta, ecbdata->label_path[1], reset, name_b_tab);
1304                 ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
1305         }
1306
1307         if (diff_suppress_blank_empty
1308             && len == 2 && line[0] == ' ' && line[1] == '\n') {
1309                 line[0] = '\n';
1310                 len = 1;
1311         }
1312
1313         if (line[0] == '@') {
1314                 if (ecbdata->diff_words)
1315                         diff_words_flush(ecbdata);
1316                 len = sane_truncate_line(ecbdata, line, len);
1317                 find_lno(line, ecbdata);
1318                 emit_hunk_header(ecbdata, line, len);
1319                 if (line[len-1] != '\n')
1320                         putc('\n', o->file);
1321                 return;
1322         }
1323
1324         if (ecbdata->diff_words) {
1325                 if (line[0] == '-') {
1326                         diff_words_append(line, len,
1327                                           &ecbdata->diff_words->minus);
1328                         return;
1329                 } else if (line[0] == '+') {
1330                         diff_words_append(line, len,
1331                                           &ecbdata->diff_words->plus);
1332                         return;
1333                 } else if (starts_with(line, "\\ ")) {
1334                         /*
1335                          * Eat the "no newline at eof" marker as if we
1336                          * saw a "+" or "-" line with nothing on it,
1337                          * and return without diff_words_flush() to
1338                          * defer processing. If this is the end of
1339                          * preimage, more "+" lines may come after it.
1340                          */
1341                         return;
1342                 }
1343                 diff_words_flush(ecbdata);
1344                 if (ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN) {
1345                         emit_line(o, context, reset, line, len);
1346                         fputs("~\n", o->file);
1347                 } else {
1348                         /*
1349                          * Skip the prefix character, if any.  With
1350                          * diff_suppress_blank_empty, there may be
1351                          * none.
1352                          */
1353                         if (line[0] != '\n') {
1354                               line++;
1355                               len--;
1356                         }
1357                         emit_line(o, context, reset, line, len);
1358                 }
1359                 return;
1360         }
1361
1362         switch (line[0]) {
1363         case '+':
1364                 ecbdata->lno_in_postimage++;
1365                 emit_add_line(reset, ecbdata, line + 1, len - 1);
1366                 break;
1367         case '-':
1368                 ecbdata->lno_in_preimage++;
1369                 emit_del_line(reset, ecbdata, line + 1, len - 1);
1370                 break;
1371         case ' ':
1372                 ecbdata->lno_in_postimage++;
1373                 ecbdata->lno_in_preimage++;
1374                 emit_context_line(reset, ecbdata, line + 1, len - 1);
1375                 break;
1376         default:
1377                 /* incomplete line at the end */
1378                 ecbdata->lno_in_preimage++;
1379                 emit_line(o, diff_get_color(ecbdata->color_diff, DIFF_CONTEXT),
1380                           reset, line, len);
1381                 break;
1382         }
1383 }
1384
1385 static char *pprint_rename(const char *a, const char *b)
1386 {
1387         const char *old = a;
1388         const char *new = b;
1389         struct strbuf name = STRBUF_INIT;
1390         int pfx_length, sfx_length;
1391         int pfx_adjust_for_slash;
1392         int len_a = strlen(a);
1393         int len_b = strlen(b);
1394         int a_midlen, b_midlen;
1395         int qlen_a = quote_c_style(a, NULL, NULL, 0);
1396         int qlen_b = quote_c_style(b, NULL, NULL, 0);
1397
1398         if (qlen_a || qlen_b) {
1399                 quote_c_style(a, &name, NULL, 0);
1400                 strbuf_addstr(&name, " => ");
1401                 quote_c_style(b, &name, NULL, 0);
1402                 return strbuf_detach(&name, NULL);
1403         }
1404
1405         /* Find common prefix */
1406         pfx_length = 0;
1407         while (*old && *new && *old == *new) {
1408                 if (*old == '/')
1409                         pfx_length = old - a + 1;
1410                 old++;
1411                 new++;
1412         }
1413
1414         /* Find common suffix */
1415         old = a + len_a;
1416         new = b + len_b;
1417         sfx_length = 0;
1418         /*
1419          * If there is a common prefix, it must end in a slash.  In
1420          * that case we let this loop run 1 into the prefix to see the
1421          * same slash.
1422          *
1423          * If there is no common prefix, we cannot do this as it would
1424          * underrun the input strings.
1425          */
1426         pfx_adjust_for_slash = (pfx_length ? 1 : 0);
1427         while (a + pfx_length - pfx_adjust_for_slash <= old &&
1428                b + pfx_length - pfx_adjust_for_slash <= new &&
1429                *old == *new) {
1430                 if (*old == '/')
1431                         sfx_length = len_a - (old - a);
1432                 old--;
1433                 new--;
1434         }
1435
1436         /*
1437          * pfx{mid-a => mid-b}sfx
1438          * {pfx-a => pfx-b}sfx
1439          * pfx{sfx-a => sfx-b}
1440          * name-a => name-b
1441          */
1442         a_midlen = len_a - pfx_length - sfx_length;
1443         b_midlen = len_b - pfx_length - sfx_length;
1444         if (a_midlen < 0)
1445                 a_midlen = 0;
1446         if (b_midlen < 0)
1447                 b_midlen = 0;
1448
1449         strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
1450         if (pfx_length + sfx_length) {
1451                 strbuf_add(&name, a, pfx_length);
1452                 strbuf_addch(&name, '{');
1453         }
1454         strbuf_add(&name, a + pfx_length, a_midlen);
1455         strbuf_addstr(&name, " => ");
1456         strbuf_add(&name, b + pfx_length, b_midlen);
1457         if (pfx_length + sfx_length) {
1458                 strbuf_addch(&name, '}');
1459                 strbuf_add(&name, a + len_a - sfx_length, sfx_length);
1460         }
1461         return strbuf_detach(&name, NULL);
1462 }
1463
1464 struct diffstat_t {
1465         int nr;
1466         int alloc;
1467         struct diffstat_file {
1468                 char *from_name;
1469                 char *name;
1470                 char *print_name;
1471                 unsigned is_unmerged:1;
1472                 unsigned is_binary:1;
1473                 unsigned is_renamed:1;
1474                 unsigned is_interesting:1;
1475                 uintmax_t added, deleted;
1476         } **files;
1477 };
1478
1479 static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
1480                                           const char *name_a,
1481                                           const char *name_b)
1482 {
1483         struct diffstat_file *x;
1484         x = xcalloc(1, sizeof(*x));
1485         ALLOC_GROW(diffstat->files, diffstat->nr + 1, diffstat->alloc);
1486         diffstat->files[diffstat->nr++] = x;
1487         if (name_b) {
1488                 x->from_name = xstrdup(name_a);
1489                 x->name = xstrdup(name_b);
1490                 x->is_renamed = 1;
1491         }
1492         else {
1493                 x->from_name = NULL;
1494                 x->name = xstrdup(name_a);
1495         }
1496         return x;
1497 }
1498
1499 static void diffstat_consume(void *priv, char *line, unsigned long len)
1500 {
1501         struct diffstat_t *diffstat = priv;
1502         struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
1503
1504         if (line[0] == '+')
1505                 x->added++;
1506         else if (line[0] == '-')
1507                 x->deleted++;
1508 }
1509
1510 const char mime_boundary_leader[] = "------------";
1511
1512 static int scale_linear(int it, int width, int max_change)
1513 {
1514         if (!it)
1515                 return 0;
1516         /*
1517          * make sure that at least one '-' or '+' is printed if
1518          * there is any change to this path. The easiest way is to
1519          * scale linearly as if the alloted width is one column shorter
1520          * than it is, and then add 1 to the result.
1521          */
1522         return 1 + (it * (width - 1) / max_change);
1523 }
1524
1525 static void show_name(FILE *file,
1526                       const char *prefix, const char *name, int len)
1527 {
1528         fprintf(file, " %s%-*s |", prefix, len, name);
1529 }
1530
1531 static void show_graph(FILE *file, char ch, int cnt, const char *set, const char *reset)
1532 {
1533         if (cnt <= 0)
1534                 return;
1535         fprintf(file, "%s", set);
1536         while (cnt--)
1537                 putc(ch, file);
1538         fprintf(file, "%s", reset);
1539 }
1540
1541 static void fill_print_name(struct diffstat_file *file)
1542 {
1543         char *pname;
1544
1545         if (file->print_name)
1546                 return;
1547
1548         if (!file->is_renamed) {
1549                 struct strbuf buf = STRBUF_INIT;
1550                 if (quote_c_style(file->name, &buf, NULL, 0)) {
1551                         pname = strbuf_detach(&buf, NULL);
1552                 } else {
1553                         pname = file->name;
1554                         strbuf_release(&buf);
1555                 }
1556         } else {
1557                 pname = pprint_rename(file->from_name, file->name);
1558         }
1559         file->print_name = pname;
1560 }
1561
1562 int print_stat_summary(FILE *fp, int files, int insertions, int deletions)
1563 {
1564         struct strbuf sb = STRBUF_INIT;
1565         int ret;
1566
1567         if (!files) {
1568                 assert(insertions == 0 && deletions == 0);
1569                 return fprintf(fp, "%s\n", " 0 files changed");
1570         }
1571
1572         strbuf_addf(&sb,
1573                     (files == 1) ? " %d file changed" : " %d files changed",
1574                     files);
1575
1576         /*
1577          * For binary diff, the caller may want to print "x files
1578          * changed" with insertions == 0 && deletions == 0.
1579          *
1580          * Not omitting "0 insertions(+), 0 deletions(-)" in this case
1581          * is probably less confusing (i.e skip over "2 files changed
1582          * but nothing about added/removed lines? Is this a bug in Git?").
1583          */
1584         if (insertions || deletions == 0) {
1585                 strbuf_addf(&sb,
1586                             (insertions == 1) ? ", %d insertion(+)" : ", %d insertions(+)",
1587                             insertions);
1588         }
1589
1590         if (deletions || insertions == 0) {
1591                 strbuf_addf(&sb,
1592                             (deletions == 1) ? ", %d deletion(-)" : ", %d deletions(-)",
1593                             deletions);
1594         }
1595         strbuf_addch(&sb, '\n');
1596         ret = fputs(sb.buf, fp);
1597         strbuf_release(&sb);
1598         return ret;
1599 }
1600
1601 static void show_stats(struct diffstat_t *data, struct diff_options *options)
1602 {
1603         int i, len, add, del, adds = 0, dels = 0;
1604         uintmax_t max_change = 0, max_len = 0;
1605         int total_files = data->nr, count;
1606         int width, name_width, graph_width, number_width = 0, bin_width = 0;
1607         const char *reset, *add_c, *del_c;
1608         const char *line_prefix = "";
1609         int extra_shown = 0;
1610
1611         if (data->nr == 0)
1612                 return;
1613
1614         line_prefix = diff_line_prefix(options);
1615         count = options->stat_count ? options->stat_count : data->nr;
1616
1617         reset = diff_get_color_opt(options, DIFF_RESET);
1618         add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
1619         del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
1620
1621         /*
1622          * Find the longest filename and max number of changes
1623          */
1624         for (i = 0; (i < count) && (i < data->nr); i++) {
1625                 struct diffstat_file *file = data->files[i];
1626                 uintmax_t change = file->added + file->deleted;
1627
1628                 if (!file->is_interesting && (change == 0)) {
1629                         count++; /* not shown == room for one more */
1630                         continue;
1631                 }
1632                 fill_print_name(file);
1633                 len = strlen(file->print_name);
1634                 if (max_len < len)
1635                         max_len = len;
1636
1637                 if (file->is_unmerged) {
1638                         /* "Unmerged" is 8 characters */
1639                         bin_width = bin_width < 8 ? 8 : bin_width;
1640                         continue;
1641                 }
1642                 if (file->is_binary) {
1643                         /* "Bin XXX -> YYY bytes" */
1644                         int w = 14 + decimal_width(file->added)
1645                                 + decimal_width(file->deleted);
1646                         bin_width = bin_width < w ? w : bin_width;
1647                         /* Display change counts aligned with "Bin" */
1648                         number_width = 3;
1649                         continue;
1650                 }
1651
1652                 if (max_change < change)
1653                         max_change = change;
1654         }
1655         count = i; /* where we can stop scanning in data->files[] */
1656
1657         /*
1658          * We have width = stat_width or term_columns() columns total.
1659          * We want a maximum of min(max_len, stat_name_width) for the name part.
1660          * We want a maximum of min(max_change, stat_graph_width) for the +- part.
1661          * We also need 1 for " " and 4 + decimal_width(max_change)
1662          * for " | NNNN " and one the empty column at the end, altogether
1663          * 6 + decimal_width(max_change).
1664          *
1665          * If there's not enough space, we will use the smaller of
1666          * stat_name_width (if set) and 5/8*width for the filename,
1667          * and the rest for constant elements + graph part, but no more
1668          * than stat_graph_width for the graph part.
1669          * (5/8 gives 50 for filename and 30 for the constant parts + graph
1670          * for the standard terminal size).
1671          *
1672          * In other words: stat_width limits the maximum width, and
1673          * stat_name_width fixes the maximum width of the filename,
1674          * and is also used to divide available columns if there
1675          * aren't enough.
1676          *
1677          * Binary files are displayed with "Bin XXX -> YYY bytes"
1678          * instead of the change count and graph. This part is treated
1679          * similarly to the graph part, except that it is not
1680          * "scaled". If total width is too small to accommodate the
1681          * guaranteed minimum width of the filename part and the
1682          * separators and this message, this message will "overflow"
1683          * making the line longer than the maximum width.
1684          */
1685
1686         if (options->stat_width == -1)
1687                 width = term_columns() - strlen(line_prefix);
1688         else
1689                 width = options->stat_width ? options->stat_width : 80;
1690         number_width = decimal_width(max_change) > number_width ?
1691                 decimal_width(max_change) : number_width;
1692
1693         if (options->stat_graph_width == -1)
1694                 options->stat_graph_width = diff_stat_graph_width;
1695
1696         /*
1697          * Guarantee 3/8*16==6 for the graph part
1698          * and 5/8*16==10 for the filename part
1699          */
1700         if (width < 16 + 6 + number_width)
1701                 width = 16 + 6 + number_width;
1702
1703         /*
1704          * First assign sizes that are wanted, ignoring available width.
1705          * strlen("Bin XXX -> YYY bytes") == bin_width, and the part
1706          * starting from "XXX" should fit in graph_width.
1707          */
1708         graph_width = max_change + 4 > bin_width ? max_change : bin_width - 4;
1709         if (options->stat_graph_width &&
1710             options->stat_graph_width < graph_width)
1711                 graph_width = options->stat_graph_width;
1712
1713         name_width = (options->stat_name_width > 0 &&
1714                       options->stat_name_width < max_len) ?
1715                 options->stat_name_width : max_len;
1716
1717         /*
1718          * Adjust adjustable widths not to exceed maximum width
1719          */
1720         if (name_width + number_width + 6 + graph_width > width) {
1721                 if (graph_width > width * 3/8 - number_width - 6) {
1722                         graph_width = width * 3/8 - number_width - 6;
1723                         if (graph_width < 6)
1724                                 graph_width = 6;
1725                 }
1726
1727                 if (options->stat_graph_width &&
1728                     graph_width > options->stat_graph_width)
1729                         graph_width = options->stat_graph_width;
1730                 if (name_width > width - number_width - 6 - graph_width)
1731                         name_width = width - number_width - 6 - graph_width;
1732                 else
1733                         graph_width = width - number_width - 6 - name_width;
1734         }
1735
1736         /*
1737          * From here name_width is the width of the name area,
1738          * and graph_width is the width of the graph area.
1739          * max_change is used to scale graph properly.
1740          */
1741         for (i = 0; i < count; i++) {
1742                 const char *prefix = "";
1743                 struct diffstat_file *file = data->files[i];
1744                 char *name = file->print_name;
1745                 uintmax_t added = file->added;
1746                 uintmax_t deleted = file->deleted;
1747                 int name_len;
1748
1749                 if (!file->is_interesting && (added + deleted == 0))
1750                         continue;
1751
1752                 /*
1753                  * "scale" the filename
1754                  */
1755                 len = name_width;
1756                 name_len = strlen(name);
1757                 if (name_width < name_len) {
1758                         char *slash;
1759                         prefix = "...";
1760                         len -= 3;
1761                         name += name_len - len;
1762                         slash = strchr(name, '/');
1763                         if (slash)
1764                                 name = slash;
1765                 }
1766
1767                 if (file->is_binary) {
1768                         fprintf(options->file, "%s", line_prefix);
1769                         show_name(options->file, prefix, name, len);
1770                         fprintf(options->file, " %*s", number_width, "Bin");
1771                         if (!added && !deleted) {
1772                                 putc('\n', options->file);
1773                                 continue;
1774                         }
1775                         fprintf(options->file, " %s%"PRIuMAX"%s",
1776                                 del_c, deleted, reset);
1777                         fprintf(options->file, " -> ");
1778                         fprintf(options->file, "%s%"PRIuMAX"%s",
1779                                 add_c, added, reset);
1780                         fprintf(options->file, " bytes");
1781                         fprintf(options->file, "\n");
1782                         continue;
1783                 }
1784                 else if (file->is_unmerged) {
1785                         fprintf(options->file, "%s", line_prefix);
1786                         show_name(options->file, prefix, name, len);
1787                         fprintf(options->file, " Unmerged\n");
1788                         continue;
1789                 }
1790
1791                 /*
1792                  * scale the add/delete
1793                  */
1794                 add = added;
1795                 del = deleted;
1796
1797                 if (graph_width <= max_change) {
1798                         int total = scale_linear(add + del, graph_width, max_change);
1799                         if (total < 2 && add && del)
1800                                 /* width >= 2 due to the sanity check */
1801                                 total = 2;
1802                         if (add < del) {
1803                                 add = scale_linear(add, graph_width, max_change);
1804                                 del = total - add;
1805                         } else {
1806                                 del = scale_linear(del, graph_width, max_change);
1807                                 add = total - del;
1808                         }
1809                 }
1810                 fprintf(options->file, "%s", line_prefix);
1811                 show_name(options->file, prefix, name, len);
1812                 fprintf(options->file, " %*"PRIuMAX"%s",
1813                         number_width, added + deleted,
1814                         added + deleted ? " " : "");
1815                 show_graph(options->file, '+', add, add_c, reset);
1816                 show_graph(options->file, '-', del, del_c, reset);
1817                 fprintf(options->file, "\n");
1818         }
1819
1820         for (i = 0; i < data->nr; i++) {
1821                 struct diffstat_file *file = data->files[i];
1822                 uintmax_t added = file->added;
1823                 uintmax_t deleted = file->deleted;
1824
1825                 if (file->is_unmerged ||
1826                     (!file->is_interesting && (added + deleted == 0))) {
1827                         total_files--;
1828                         continue;
1829                 }
1830
1831                 if (!file->is_binary) {
1832                         adds += added;
1833                         dels += deleted;
1834                 }
1835                 if (i < count)
1836                         continue;
1837                 if (!extra_shown)
1838                         fprintf(options->file, "%s ...\n", line_prefix);
1839                 extra_shown = 1;
1840         }
1841         fprintf(options->file, "%s", line_prefix);
1842         print_stat_summary(options->file, total_files, adds, dels);
1843 }
1844
1845 static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
1846 {
1847         int i, adds = 0, dels = 0, total_files = data->nr;
1848
1849         if (data->nr == 0)
1850                 return;
1851
1852         for (i = 0; i < data->nr; i++) {
1853                 int added = data->files[i]->added;
1854                 int deleted= data->files[i]->deleted;
1855
1856                 if (data->files[i]->is_unmerged ||
1857                     (!data->files[i]->is_interesting && (added + deleted == 0))) {
1858                         total_files--;
1859                 } else if (!data->files[i]->is_binary) { /* don't count bytes */
1860                         adds += added;
1861                         dels += deleted;
1862                 }
1863         }
1864         fprintf(options->file, "%s", diff_line_prefix(options));
1865         print_stat_summary(options->file, total_files, adds, dels);
1866 }
1867
1868 static void show_numstat(struct diffstat_t *data, struct diff_options *options)
1869 {
1870         int i;
1871
1872         if (data->nr == 0)
1873                 return;
1874
1875         for (i = 0; i < data->nr; i++) {
1876                 struct diffstat_file *file = data->files[i];
1877
1878                 fprintf(options->file, "%s", diff_line_prefix(options));
1879
1880                 if (file->is_binary)
1881                         fprintf(options->file, "-\t-\t");
1882                 else
1883                         fprintf(options->file,
1884                                 "%"PRIuMAX"\t%"PRIuMAX"\t",
1885                                 file->added, file->deleted);
1886                 if (options->line_termination) {
1887                         fill_print_name(file);
1888                         if (!file->is_renamed)
1889                                 write_name_quoted(file->name, options->file,
1890                                                   options->line_termination);
1891                         else {
1892                                 fputs(file->print_name, options->file);
1893                                 putc(options->line_termination, options->file);
1894                         }
1895                 } else {
1896                         if (file->is_renamed) {
1897                                 putc('\0', options->file);
1898                                 write_name_quoted(file->from_name, options->file, '\0');
1899                         }
1900                         write_name_quoted(file->name, options->file, '\0');
1901                 }
1902         }
1903 }
1904
1905 struct dirstat_file {
1906         const char *name;
1907         unsigned long changed;
1908 };
1909
1910 struct dirstat_dir {
1911         struct dirstat_file *files;
1912         int alloc, nr, permille, cumulative;
1913 };
1914
1915 static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
1916                 unsigned long changed, const char *base, int baselen)
1917 {
1918         unsigned long this_dir = 0;
1919         unsigned int sources = 0;
1920         const char *line_prefix = diff_line_prefix(opt);
1921
1922         while (dir->nr) {
1923                 struct dirstat_file *f = dir->files;
1924                 int namelen = strlen(f->name);
1925                 unsigned long this;
1926                 char *slash;
1927
1928                 if (namelen < baselen)
1929                         break;
1930                 if (memcmp(f->name, base, baselen))
1931                         break;
1932                 slash = strchr(f->name + baselen, '/');
1933                 if (slash) {
1934                         int newbaselen = slash + 1 - f->name;
1935                         this = gather_dirstat(opt, dir, changed, f->name, newbaselen);
1936                         sources++;
1937                 } else {
1938                         this = f->changed;
1939                         dir->files++;
1940                         dir->nr--;
1941                         sources += 2;
1942                 }
1943                 this_dir += this;
1944         }
1945
1946         /*
1947          * We don't report dirstat's for
1948          *  - the top level
1949          *  - or cases where everything came from a single directory
1950          *    under this directory (sources == 1).
1951          */
1952         if (baselen && sources != 1) {
1953                 if (this_dir) {
1954                         int permille = this_dir * 1000 / changed;
1955                         if (permille >= dir->permille) {
1956                                 fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
1957                                         permille / 10, permille % 10, baselen, base);
1958                                 if (!dir->cumulative)
1959                                         return 0;
1960                         }
1961                 }
1962         }
1963         return this_dir;
1964 }
1965
1966 static int dirstat_compare(const void *_a, const void *_b)
1967 {
1968         const struct dirstat_file *a = _a;
1969         const struct dirstat_file *b = _b;
1970         return strcmp(a->name, b->name);
1971 }
1972
1973 static void show_dirstat(struct diff_options *options)
1974 {
1975         int i;
1976         unsigned long changed;
1977         struct dirstat_dir dir;
1978         struct diff_queue_struct *q = &diff_queued_diff;
1979
1980         dir.files = NULL;
1981         dir.alloc = 0;
1982         dir.nr = 0;
1983         dir.permille = options->dirstat_permille;
1984         dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1985
1986         changed = 0;
1987         for (i = 0; i < q->nr; i++) {
1988                 struct diff_filepair *p = q->queue[i];
1989                 const char *name;
1990                 unsigned long copied, added, damage;
1991                 int content_changed;
1992
1993                 name = p->two->path ? p->two->path : p->one->path;
1994
1995                 if (p->one->oid_valid && p->two->oid_valid)
1996                         content_changed = oidcmp(&p->one->oid, &p->two->oid);
1997                 else
1998                         content_changed = 1;
1999
2000                 if (!content_changed) {
2001                         /*
2002                          * The SHA1 has not changed, so pre-/post-content is
2003                          * identical. We can therefore skip looking at the
2004                          * file contents altogether.
2005                          */
2006                         damage = 0;
2007                         goto found_damage;
2008                 }
2009
2010                 if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE)) {
2011                         /*
2012                          * In --dirstat-by-file mode, we don't really need to
2013                          * look at the actual file contents at all.
2014                          * The fact that the SHA1 changed is enough for us to
2015                          * add this file to the list of results
2016                          * (with each file contributing equal damage).
2017                          */
2018                         damage = 1;
2019                         goto found_damage;
2020                 }
2021
2022                 if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
2023                         diff_populate_filespec(p->one, 0);
2024                         diff_populate_filespec(p->two, 0);
2025                         diffcore_count_changes(p->one, p->two, NULL, NULL,
2026                                                &copied, &added);
2027                         diff_free_filespec_data(p->one);
2028                         diff_free_filespec_data(p->two);
2029                 } else if (DIFF_FILE_VALID(p->one)) {
2030                         diff_populate_filespec(p->one, CHECK_SIZE_ONLY);
2031                         copied = added = 0;
2032                         diff_free_filespec_data(p->one);
2033                 } else if (DIFF_FILE_VALID(p->two)) {
2034                         diff_populate_filespec(p->two, CHECK_SIZE_ONLY);
2035                         copied = 0;
2036                         added = p->two->size;
2037                         diff_free_filespec_data(p->two);
2038                 } else
2039                         continue;
2040
2041                 /*
2042                  * Original minus copied is the removed material,
2043                  * added is the new material.  They are both damages
2044                  * made to the preimage.
2045                  * If the resulting damage is zero, we know that
2046                  * diffcore_count_changes() considers the two entries to
2047                  * be identical, but since content_changed is true, we
2048                  * know that there must have been _some_ kind of change,
2049                  * so we force all entries to have damage > 0.
2050                  */
2051                 damage = (p->one->size - copied) + added;
2052                 if (!damage)
2053                         damage = 1;
2054
2055 found_damage:
2056                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
2057                 dir.files[dir.nr].name = name;
2058                 dir.files[dir.nr].changed = damage;
2059                 changed += damage;
2060                 dir.nr++;
2061         }
2062
2063         /* This can happen even with many files, if everything was renames */
2064         if (!changed)
2065                 return;
2066
2067         /* Show all directories with more than x% of the changes */
2068         QSORT(dir.files, dir.nr, dirstat_compare);
2069         gather_dirstat(options, &dir, changed, "", 0);
2070 }
2071
2072 static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
2073 {
2074         int i;
2075         unsigned long changed;
2076         struct dirstat_dir dir;
2077
2078         if (data->nr == 0)
2079                 return;
2080
2081         dir.files = NULL;
2082         dir.alloc = 0;
2083         dir.nr = 0;
2084         dir.permille = options->dirstat_permille;
2085         dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
2086
2087         changed = 0;
2088         for (i = 0; i < data->nr; i++) {
2089                 struct diffstat_file *file = data->files[i];
2090                 unsigned long damage = file->added + file->deleted;
2091                 if (file->is_binary)
2092                         /*
2093                          * binary files counts bytes, not lines. Must find some
2094                          * way to normalize binary bytes vs. textual lines.
2095                          * The following heuristic assumes that there are 64
2096                          * bytes per "line".
2097                          * This is stupid and ugly, but very cheap...
2098                          */
2099                         damage = (damage + 63) / 64;
2100                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
2101                 dir.files[dir.nr].name = file->name;
2102                 dir.files[dir.nr].changed = damage;
2103                 changed += damage;
2104                 dir.nr++;
2105         }
2106
2107         /* This can happen even with many files, if everything was renames */
2108         if (!changed)
2109                 return;
2110
2111         /* Show all directories with more than x% of the changes */
2112         QSORT(dir.files, dir.nr, dirstat_compare);
2113         gather_dirstat(options, &dir, changed, "", 0);
2114 }
2115
2116 static void free_diffstat_info(struct diffstat_t *diffstat)
2117 {
2118         int i;
2119         for (i = 0; i < diffstat->nr; i++) {
2120                 struct diffstat_file *f = diffstat->files[i];
2121                 if (f->name != f->print_name)
2122                         free(f->print_name);
2123                 free(f->name);
2124                 free(f->from_name);
2125                 free(f);
2126         }
2127         free(diffstat->files);
2128 }
2129
2130 struct checkdiff_t {
2131         const char *filename;
2132         int lineno;
2133         int conflict_marker_size;
2134         struct diff_options *o;
2135         unsigned ws_rule;
2136         unsigned status;
2137 };
2138
2139 static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
2140 {
2141         char firstchar;
2142         int cnt;
2143
2144         if (len < marker_size + 1)
2145                 return 0;
2146         firstchar = line[0];
2147         switch (firstchar) {
2148         case '=': case '>': case '<': case '|':
2149                 break;
2150         default:
2151                 return 0;
2152         }
2153         for (cnt = 1; cnt < marker_size; cnt++)
2154                 if (line[cnt] != firstchar)
2155                         return 0;
2156         /* line[1] thru line[marker_size-1] are same as firstchar */
2157         if (len < marker_size + 1 || !isspace(line[marker_size]))
2158                 return 0;
2159         return 1;
2160 }
2161
2162 static void checkdiff_consume(void *priv, char *line, unsigned long len)
2163 {
2164         struct checkdiff_t *data = priv;
2165         int marker_size = data->conflict_marker_size;
2166         const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
2167         const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
2168         const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
2169         char *err;
2170         const char *line_prefix;
2171
2172         assert(data->o);
2173         line_prefix = diff_line_prefix(data->o);
2174
2175         if (line[0] == '+') {
2176                 unsigned bad;
2177                 data->lineno++;
2178                 if (is_conflict_marker(line + 1, marker_size, len - 1)) {
2179                         data->status |= 1;
2180                         fprintf(data->o->file,
2181                                 "%s%s:%d: leftover conflict marker\n",
2182                                 line_prefix, data->filename, data->lineno);
2183                 }
2184                 bad = ws_check(line + 1, len - 1, data->ws_rule);
2185                 if (!bad)
2186                         return;
2187                 data->status |= bad;
2188                 err = whitespace_error_string(bad);
2189                 fprintf(data->o->file, "%s%s:%d: %s.\n",
2190                         line_prefix, data->filename, data->lineno, err);
2191                 free(err);
2192                 emit_line(data->o, set, reset, line, 1);
2193                 ws_check_emit(line + 1, len - 1, data->ws_rule,
2194                               data->o->file, set, reset, ws);
2195         } else if (line[0] == ' ') {
2196                 data->lineno++;
2197         } else if (line[0] == '@') {
2198                 char *plus = strchr(line, '+');
2199                 if (plus)
2200                         data->lineno = strtol(plus, NULL, 10) - 1;
2201                 else
2202                         die("invalid diff");
2203         }
2204 }
2205
2206 static unsigned char *deflate_it(char *data,
2207                                  unsigned long size,
2208                                  unsigned long *result_size)
2209 {
2210         int bound;
2211         unsigned char *deflated;
2212         git_zstream stream;
2213
2214         git_deflate_init(&stream, zlib_compression_level);
2215         bound = git_deflate_bound(&stream, size);
2216         deflated = xmalloc(bound);
2217         stream.next_out = deflated;
2218         stream.avail_out = bound;
2219
2220         stream.next_in = (unsigned char *)data;
2221         stream.avail_in = size;
2222         while (git_deflate(&stream, Z_FINISH) == Z_OK)
2223                 ; /* nothing */
2224         git_deflate_end(&stream);
2225         *result_size = stream.total_out;
2226         return deflated;
2227 }
2228
2229 static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two,
2230                                   const char *prefix)
2231 {
2232         void *cp;
2233         void *delta;
2234         void *deflated;
2235         void *data;
2236         unsigned long orig_size;
2237         unsigned long delta_size;
2238         unsigned long deflate_size;
2239         unsigned long data_size;
2240
2241         /* We could do deflated delta, or we could do just deflated two,
2242          * whichever is smaller.
2243          */
2244         delta = NULL;
2245         deflated = deflate_it(two->ptr, two->size, &deflate_size);
2246         if (one->size && two->size) {
2247                 delta = diff_delta(one->ptr, one->size,
2248                                    two->ptr, two->size,
2249                                    &delta_size, deflate_size);
2250                 if (delta) {
2251                         void *to_free = delta;
2252                         orig_size = delta_size;
2253                         delta = deflate_it(delta, delta_size, &delta_size);
2254                         free(to_free);
2255                 }
2256         }
2257
2258         if (delta && delta_size < deflate_size) {
2259                 fprintf(file, "%sdelta %lu\n", prefix, orig_size);
2260                 free(deflated);
2261                 data = delta;
2262                 data_size = delta_size;
2263         }
2264         else {
2265                 fprintf(file, "%sliteral %lu\n", prefix, two->size);
2266                 free(delta);
2267                 data = deflated;
2268                 data_size = deflate_size;
2269         }
2270
2271         /* emit data encoded in base85 */
2272         cp = data;
2273         while (data_size) {
2274                 int bytes = (52 < data_size) ? 52 : data_size;
2275                 char line[70];
2276                 data_size -= bytes;
2277                 if (bytes <= 26)
2278                         line[0] = bytes + 'A' - 1;
2279                 else
2280                         line[0] = bytes - 26 + 'a' - 1;
2281                 encode_85(line + 1, cp, bytes);
2282                 cp = (char *) cp + bytes;
2283                 fprintf(file, "%s", prefix);
2284                 fputs(line, file);
2285                 fputc('\n', file);
2286         }
2287         fprintf(file, "%s\n", prefix);
2288         free(data);
2289 }
2290
2291 static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two,
2292                              const char *prefix)
2293 {
2294         fprintf(file, "%sGIT binary patch\n", prefix);
2295         emit_binary_diff_body(file, one, two, prefix);
2296         emit_binary_diff_body(file, two, one, prefix);
2297 }
2298
2299 int diff_filespec_is_binary(struct diff_filespec *one)
2300 {
2301         if (one->is_binary == -1) {
2302                 diff_filespec_load_driver(one);
2303                 if (one->driver->binary != -1)
2304                         one->is_binary = one->driver->binary;
2305                 else {
2306                         if (!one->data && DIFF_FILE_VALID(one))
2307                                 diff_populate_filespec(one, CHECK_BINARY);
2308                         if (one->is_binary == -1 && one->data)
2309                                 one->is_binary = buffer_is_binary(one->data,
2310                                                 one->size);
2311                         if (one->is_binary == -1)
2312                                 one->is_binary = 0;
2313                 }
2314         }
2315         return one->is_binary;
2316 }
2317
2318 static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
2319 {
2320         diff_filespec_load_driver(one);
2321         return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
2322 }
2323
2324 void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
2325 {
2326         if (!options->a_prefix)
2327                 options->a_prefix = a;
2328         if (!options->b_prefix)
2329                 options->b_prefix = b;
2330 }
2331
2332 struct userdiff_driver *get_textconv(struct diff_filespec *one)
2333 {
2334         if (!DIFF_FILE_VALID(one))
2335                 return NULL;
2336
2337         diff_filespec_load_driver(one);
2338         return userdiff_get_textconv(one->driver);
2339 }
2340
2341 static void builtin_diff(const char *name_a,
2342                          const char *name_b,
2343                          struct diff_filespec *one,
2344                          struct diff_filespec *two,
2345                          const char *xfrm_msg,
2346                          int must_show_header,
2347                          struct diff_options *o,
2348                          int complete_rewrite)
2349 {
2350         mmfile_t mf1, mf2;
2351         const char *lbl[2];
2352         char *a_one, *b_two;
2353         const char *meta = diff_get_color_opt(o, DIFF_METAINFO);
2354         const char *reset = diff_get_color_opt(o, DIFF_RESET);
2355         const char *a_prefix, *b_prefix;
2356         struct userdiff_driver *textconv_one = NULL;
2357         struct userdiff_driver *textconv_two = NULL;
2358         struct strbuf header = STRBUF_INIT;
2359         const char *line_prefix = diff_line_prefix(o);
2360
2361         diff_set_mnemonic_prefix(o, "a/", "b/");
2362         if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
2363                 a_prefix = o->b_prefix;
2364                 b_prefix = o->a_prefix;
2365         } else {
2366                 a_prefix = o->a_prefix;
2367                 b_prefix = o->b_prefix;
2368         }
2369
2370         if (o->submodule_format == DIFF_SUBMODULE_LOG &&
2371             (!one->mode || S_ISGITLINK(one->mode)) &&
2372             (!two->mode || S_ISGITLINK(two->mode))) {
2373                 const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
2374                 const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
2375                 show_submodule_summary(o->file, one->path ? one->path : two->path,
2376                                 line_prefix,
2377                                 &one->oid, &two->oid,
2378                                 two->dirty_submodule,
2379                                 meta, del, add, reset);
2380                 return;
2381         } else if (o->submodule_format == DIFF_SUBMODULE_INLINE_DIFF &&
2382                    (!one->mode || S_ISGITLINK(one->mode)) &&
2383                    (!two->mode || S_ISGITLINK(two->mode))) {
2384                 const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
2385                 const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
2386                 show_submodule_inline_diff(o->file, one->path ? one->path : two->path,
2387                                 line_prefix,
2388                                 &one->oid, &two->oid,
2389                                 two->dirty_submodule,
2390                                 meta, del, add, reset, o);
2391                 return;
2392         }
2393
2394         if (DIFF_OPT_TST(o, ALLOW_TEXTCONV)) {
2395                 textconv_one = get_textconv(one);
2396                 textconv_two = get_textconv(two);
2397         }
2398
2399         /* Never use a non-valid filename anywhere if at all possible */
2400         name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
2401         name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
2402
2403         a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
2404         b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
2405         lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
2406         lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
2407         strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, meta, a_one, b_two, reset);
2408         if (lbl[0][0] == '/') {
2409                 /* /dev/null */
2410                 strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, meta, two->mode, reset);
2411                 if (xfrm_msg)
2412                         strbuf_addstr(&header, xfrm_msg);
2413                 must_show_header = 1;
2414         }
2415         else if (lbl[1][0] == '/') {
2416                 strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, meta, one->mode, reset);
2417                 if (xfrm_msg)
2418                         strbuf_addstr(&header, xfrm_msg);
2419                 must_show_header = 1;
2420         }
2421         else {
2422                 if (one->mode != two->mode) {
2423                         strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, meta, one->mode, reset);
2424                         strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, meta, two->mode, reset);
2425                         must_show_header = 1;
2426                 }
2427                 if (xfrm_msg)
2428                         strbuf_addstr(&header, xfrm_msg);
2429
2430                 /*
2431                  * we do not run diff between different kind
2432                  * of objects.
2433                  */
2434                 if ((one->mode ^ two->mode) & S_IFMT)
2435                         goto free_ab_and_return;
2436                 if (complete_rewrite &&
2437                     (textconv_one || !diff_filespec_is_binary(one)) &&
2438                     (textconv_two || !diff_filespec_is_binary(two))) {
2439                         fprintf(o->file, "%s", header.buf);
2440                         strbuf_reset(&header);
2441                         emit_rewrite_diff(name_a, name_b, one, two,
2442                                                 textconv_one, textconv_two, o);
2443                         o->found_changes = 1;
2444                         goto free_ab_and_return;
2445                 }
2446         }
2447
2448         if (o->irreversible_delete && lbl[1][0] == '/') {
2449                 fprintf(o->file, "%s", header.buf);
2450                 strbuf_reset(&header);
2451                 goto free_ab_and_return;
2452         } else if (!DIFF_OPT_TST(o, TEXT) &&
2453             ( (!textconv_one && diff_filespec_is_binary(one)) ||
2454               (!textconv_two && diff_filespec_is_binary(two)) )) {
2455                 if (!one->data && !two->data &&
2456                     S_ISREG(one->mode) && S_ISREG(two->mode) &&
2457                     !DIFF_OPT_TST(o, BINARY)) {
2458                         if (!oidcmp(&one->oid, &two->oid)) {
2459                                 if (must_show_header)
2460                                         fprintf(o->file, "%s", header.buf);
2461                                 goto free_ab_and_return;
2462                         }
2463                         fprintf(o->file, "%s", header.buf);
2464                         fprintf(o->file, "%sBinary files %s and %s differ\n",
2465                                 line_prefix, lbl[0], lbl[1]);
2466                         goto free_ab_and_return;
2467                 }
2468                 if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2469                         die("unable to read files to diff");
2470                 /* Quite common confusing case */
2471                 if (mf1.size == mf2.size &&
2472                     !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
2473                         if (must_show_header)
2474                                 fprintf(o->file, "%s", header.buf);
2475                         goto free_ab_and_return;
2476                 }
2477                 fprintf(o->file, "%s", header.buf);
2478                 strbuf_reset(&header);
2479                 if (DIFF_OPT_TST(o, BINARY))
2480                         emit_binary_diff(o->file, &mf1, &mf2, line_prefix);
2481                 else
2482                         fprintf(o->file, "%sBinary files %s and %s differ\n",
2483                                 line_prefix, lbl[0], lbl[1]);
2484                 o->found_changes = 1;
2485         } else {
2486                 /* Crazy xdl interfaces.. */
2487                 const char *diffopts = getenv("GIT_DIFF_OPTS");
2488                 const char *v;
2489                 xpparam_t xpp;
2490                 xdemitconf_t xecfg;
2491                 struct emit_callback ecbdata;
2492                 const struct userdiff_funcname *pe;
2493
2494                 if (must_show_header) {
2495                         fprintf(o->file, "%s", header.buf);
2496                         strbuf_reset(&header);
2497                 }
2498
2499                 mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
2500                 mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
2501
2502                 pe = diff_funcname_pattern(one);
2503                 if (!pe)
2504                         pe = diff_funcname_pattern(two);
2505
2506                 memset(&xpp, 0, sizeof(xpp));
2507                 memset(&xecfg, 0, sizeof(xecfg));
2508                 memset(&ecbdata, 0, sizeof(ecbdata));
2509                 ecbdata.label_path = lbl;
2510                 ecbdata.color_diff = want_color(o->use_color);
2511                 ecbdata.ws_rule = whitespace_rule(name_b);
2512                 if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
2513                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
2514                 ecbdata.opt = o;
2515                 ecbdata.header = header.len ? &header : NULL;
2516                 xpp.flags = o->xdl_opts;
2517                 xecfg.ctxlen = o->context;
2518                 xecfg.interhunkctxlen = o->interhunkcontext;
2519                 xecfg.flags = XDL_EMIT_FUNCNAMES;
2520                 if (DIFF_OPT_TST(o, FUNCCONTEXT))
2521                         xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
2522                 if (pe)
2523                         xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
2524                 if (!diffopts)
2525                         ;
2526                 else if (skip_prefix(diffopts, "--unified=", &v))
2527                         xecfg.ctxlen = strtoul(v, NULL, 10);
2528                 else if (skip_prefix(diffopts, "-u", &v))
2529                         xecfg.ctxlen = strtoul(v, NULL, 10);
2530                 if (o->word_diff)
2531                         init_diff_words_data(&ecbdata, o, one, two);
2532                 if (xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
2533                                   &xpp, &xecfg))
2534                         die("unable to generate diff for %s", one->path);
2535                 if (o->word_diff)
2536                         free_diff_words_data(&ecbdata);
2537                 if (textconv_one)
2538                         free(mf1.ptr);
2539                 if (textconv_two)
2540                         free(mf2.ptr);
2541                 xdiff_clear_find_func(&xecfg);
2542         }
2543
2544  free_ab_and_return:
2545         strbuf_release(&header);
2546         diff_free_filespec_data(one);
2547         diff_free_filespec_data(two);
2548         free(a_one);
2549         free(b_two);
2550         return;
2551 }
2552
2553 static void builtin_diffstat(const char *name_a, const char *name_b,
2554                              struct diff_filespec *one,
2555                              struct diff_filespec *two,
2556                              struct diffstat_t *diffstat,
2557                              struct diff_options *o,
2558                              struct diff_filepair *p)
2559 {
2560         mmfile_t mf1, mf2;
2561         struct diffstat_file *data;
2562         int same_contents;
2563         int complete_rewrite = 0;
2564
2565         if (!DIFF_PAIR_UNMERGED(p)) {
2566                 if (p->status == DIFF_STATUS_MODIFIED && p->score)
2567                         complete_rewrite = 1;
2568         }
2569
2570         data = diffstat_add(diffstat, name_a, name_b);
2571         data->is_interesting = p->status != DIFF_STATUS_UNKNOWN;
2572
2573         if (!one || !two) {
2574                 data->is_unmerged = 1;
2575                 return;
2576         }
2577
2578         same_contents = !oidcmp(&one->oid, &two->oid);
2579
2580         if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
2581                 data->is_binary = 1;
2582                 if (same_contents) {
2583                         data->added = 0;
2584                         data->deleted = 0;
2585                 } else {
2586                         data->added = diff_filespec_size(two);
2587                         data->deleted = diff_filespec_size(one);
2588                 }
2589         }
2590
2591         else if (complete_rewrite) {
2592                 diff_populate_filespec(one, 0);
2593                 diff_populate_filespec(two, 0);
2594                 data->deleted = count_lines(one->data, one->size);
2595                 data->added = count_lines(two->data, two->size);
2596         }
2597
2598         else if (!same_contents) {
2599                 /* Crazy xdl interfaces.. */
2600                 xpparam_t xpp;
2601                 xdemitconf_t xecfg;
2602
2603                 if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2604                         die("unable to read files to diff");
2605
2606                 memset(&xpp, 0, sizeof(xpp));
2607                 memset(&xecfg, 0, sizeof(xecfg));
2608                 xpp.flags = o->xdl_opts;
2609                 xecfg.ctxlen = o->context;
2610                 xecfg.interhunkctxlen = o->interhunkcontext;
2611                 if (xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
2612                                   &xpp, &xecfg))
2613                         die("unable to generate diffstat for %s", one->path);
2614         }
2615
2616         diff_free_filespec_data(one);
2617         diff_free_filespec_data(two);
2618 }
2619
2620 static void builtin_checkdiff(const char *name_a, const char *name_b,
2621                               const char *attr_path,
2622                               struct diff_filespec *one,
2623                               struct diff_filespec *two,
2624                               struct diff_options *o)
2625 {
2626         mmfile_t mf1, mf2;
2627         struct checkdiff_t data;
2628
2629         if (!two)
2630                 return;
2631
2632         memset(&data, 0, sizeof(data));
2633         data.filename = name_b ? name_b : name_a;
2634         data.lineno = 0;
2635         data.o = o;
2636         data.ws_rule = whitespace_rule(attr_path);
2637         data.conflict_marker_size = ll_merge_marker_size(attr_path);
2638
2639         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2640                 die("unable to read files to diff");
2641
2642         /*
2643          * All the other codepaths check both sides, but not checking
2644          * the "old" side here is deliberate.  We are checking the newly
2645          * introduced changes, and as long as the "new" side is text, we
2646          * can and should check what it introduces.
2647          */
2648         if (diff_filespec_is_binary(two))
2649                 goto free_and_return;
2650         else {
2651                 /* Crazy xdl interfaces.. */
2652                 xpparam_t xpp;
2653                 xdemitconf_t xecfg;
2654
2655                 memset(&xpp, 0, sizeof(xpp));
2656                 memset(&xecfg, 0, sizeof(xecfg));
2657                 xecfg.ctxlen = 1; /* at least one context line */
2658                 xpp.flags = 0;
2659                 if (xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
2660                                   &xpp, &xecfg))
2661                         die("unable to generate checkdiff for %s", one->path);
2662
2663                 if (data.ws_rule & WS_BLANK_AT_EOF) {
2664                         struct emit_callback ecbdata;
2665                         int blank_at_eof;
2666
2667                         ecbdata.ws_rule = data.ws_rule;
2668                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
2669                         blank_at_eof = ecbdata.blank_at_eof_in_postimage;
2670
2671                         if (blank_at_eof) {
2672                                 static char *err;
2673                                 if (!err)
2674                                         err = whitespace_error_string(WS_BLANK_AT_EOF);
2675                                 fprintf(o->file, "%s:%d: %s.\n",
2676                                         data.filename, blank_at_eof, err);
2677                                 data.status = 1; /* report errors */
2678                         }
2679                 }
2680         }
2681  free_and_return:
2682         diff_free_filespec_data(one);
2683         diff_free_filespec_data(two);
2684         if (data.status)
2685                 DIFF_OPT_SET(o, CHECK_FAILED);
2686 }
2687
2688 struct diff_filespec *alloc_filespec(const char *path)
2689 {
2690         struct diff_filespec *spec;
2691
2692         FLEXPTR_ALLOC_STR(spec, path, path);
2693         spec->count = 1;
2694         spec->is_binary = -1;
2695         return spec;
2696 }
2697
2698 void free_filespec(struct diff_filespec *spec)
2699 {
2700         if (!--spec->count) {
2701                 diff_free_filespec_data(spec);
2702                 free(spec);
2703         }
2704 }
2705
2706 void fill_filespec(struct diff_filespec *spec, const struct object_id *oid,
2707                    int oid_valid, unsigned short mode)
2708 {
2709         if (mode) {
2710                 spec->mode = canon_mode(mode);
2711                 oidcpy(&spec->oid, oid);
2712                 spec->oid_valid = oid_valid;
2713         }
2714 }
2715
2716 /*
2717  * Given a name and sha1 pair, if the index tells us the file in
2718  * the work tree has that object contents, return true, so that
2719  * prepare_temp_file() does not have to inflate and extract.
2720  */
2721 static int reuse_worktree_file(const char *name, const struct object_id *oid, int want_file)
2722 {
2723         const struct cache_entry *ce;
2724         struct stat st;
2725         int pos, len;
2726
2727         /*
2728          * We do not read the cache ourselves here, because the
2729          * benchmark with my previous version that always reads cache
2730          * shows that it makes things worse for diff-tree comparing
2731          * two linux-2.6 kernel trees in an already checked out work
2732          * tree.  This is because most diff-tree comparisons deal with
2733          * only a small number of files, while reading the cache is
2734          * expensive for a large project, and its cost outweighs the
2735          * savings we get by not inflating the object to a temporary
2736          * file.  Practically, this code only helps when we are used
2737          * by diff-cache --cached, which does read the cache before
2738          * calling us.
2739          */
2740         if (!active_cache)
2741                 return 0;
2742
2743         /* We want to avoid the working directory if our caller
2744          * doesn't need the data in a normal file, this system
2745          * is rather slow with its stat/open/mmap/close syscalls,
2746          * and the object is contained in a pack file.  The pack
2747          * is probably already open and will be faster to obtain
2748          * the data through than the working directory.  Loose
2749          * objects however would tend to be slower as they need
2750          * to be individually opened and inflated.
2751          */
2752         if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(oid->hash))
2753                 return 0;
2754
2755         /*
2756          * Similarly, if we'd have to convert the file contents anyway, that
2757          * makes the optimization not worthwhile.
2758          */
2759         if (!want_file && would_convert_to_git(&the_index, name))
2760                 return 0;
2761
2762         len = strlen(name);
2763         pos = cache_name_pos(name, len);
2764         if (pos < 0)
2765                 return 0;
2766         ce = active_cache[pos];
2767
2768         /*
2769          * This is not the sha1 we are looking for, or
2770          * unreusable because it is not a regular file.
2771          */
2772         if (oidcmp(oid, &ce->oid) || !S_ISREG(ce->ce_mode))
2773                 return 0;
2774
2775         /*
2776          * If ce is marked as "assume unchanged", there is no
2777          * guarantee that work tree matches what we are looking for.
2778          */
2779         if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
2780                 return 0;
2781
2782         /*
2783          * If ce matches the file in the work tree, we can reuse it.
2784          */
2785         if (ce_uptodate(ce) ||
2786             (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
2787                 return 1;
2788
2789         return 0;
2790 }
2791
2792 static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
2793 {
2794         struct strbuf buf = STRBUF_INIT;
2795         char *dirty = "";
2796
2797         /* Are we looking at the work tree? */
2798         if (s->dirty_submodule)
2799                 dirty = "-dirty";
2800
2801         strbuf_addf(&buf, "Subproject commit %s%s\n",
2802                     oid_to_hex(&s->oid), dirty);
2803         s->size = buf.len;
2804         if (size_only) {
2805                 s->data = NULL;
2806                 strbuf_release(&buf);
2807         } else {
2808                 s->data = strbuf_detach(&buf, NULL);
2809                 s->should_free = 1;
2810         }
2811         return 0;
2812 }
2813
2814 /*
2815  * While doing rename detection and pickaxe operation, we may need to
2816  * grab the data for the blob (or file) for our own in-core comparison.
2817  * diff_filespec has data and size fields for this purpose.
2818  */
2819 int diff_populate_filespec(struct diff_filespec *s, unsigned int flags)
2820 {
2821         int size_only = flags & CHECK_SIZE_ONLY;
2822         int err = 0;
2823         /*
2824          * demote FAIL to WARN to allow inspecting the situation
2825          * instead of refusing.
2826          */
2827         enum safe_crlf crlf_warn = (safe_crlf == SAFE_CRLF_FAIL
2828                                     ? SAFE_CRLF_WARN
2829                                     : safe_crlf);
2830
2831         if (!DIFF_FILE_VALID(s))
2832                 die("internal error: asking to populate invalid file.");
2833         if (S_ISDIR(s->mode))
2834                 return -1;
2835
2836         if (s->data)
2837                 return 0;
2838
2839         if (size_only && 0 < s->size)
2840                 return 0;
2841
2842         if (S_ISGITLINK(s->mode))
2843                 return diff_populate_gitlink(s, size_only);
2844
2845         if (!s->oid_valid ||
2846             reuse_worktree_file(s->path, &s->oid, 0)) {
2847                 struct strbuf buf = STRBUF_INIT;
2848                 struct stat st;
2849                 int fd;
2850
2851                 if (lstat(s->path, &st) < 0) {
2852                         if (errno == ENOENT) {
2853                         err_empty:
2854                                 err = -1;
2855                         empty:
2856                                 s->data = (char *)"";
2857                                 s->size = 0;
2858                                 return err;
2859                         }
2860                 }
2861                 s->size = xsize_t(st.st_size);
2862                 if (!s->size)
2863                         goto empty;
2864                 if (S_ISLNK(st.st_mode)) {
2865                         struct strbuf sb = STRBUF_INIT;
2866
2867                         if (strbuf_readlink(&sb, s->path, s->size))
2868                                 goto err_empty;
2869                         s->size = sb.len;
2870                         s->data = strbuf_detach(&sb, NULL);
2871                         s->should_free = 1;
2872                         return 0;
2873                 }
2874
2875                 /*
2876                  * Even if the caller would be happy with getting
2877                  * only the size, we cannot return early at this
2878                  * point if the path requires us to run the content
2879                  * conversion.
2880                  */
2881                 if (size_only && !would_convert_to_git(&the_index, s->path))
2882                         return 0;
2883
2884                 /*
2885                  * Note: this check uses xsize_t(st.st_size) that may
2886                  * not be the true size of the blob after it goes
2887                  * through convert_to_git().  This may not strictly be
2888                  * correct, but the whole point of big_file_threshold
2889                  * and is_binary check being that we want to avoid
2890                  * opening the file and inspecting the contents, this
2891                  * is probably fine.
2892                  */
2893                 if ((flags & CHECK_BINARY) &&
2894                     s->size > big_file_threshold && s->is_binary == -1) {
2895                         s->is_binary = 1;
2896                         return 0;
2897                 }
2898                 fd = open(s->path, O_RDONLY);
2899                 if (fd < 0)
2900                         goto err_empty;
2901                 s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
2902                 close(fd);
2903                 s->should_munmap = 1;
2904
2905                 /*
2906                  * Convert from working tree format to canonical git format
2907                  */
2908                 if (convert_to_git(&the_index, s->path, s->data, s->size, &buf, crlf_warn)) {
2909                         size_t size = 0;
2910                         munmap(s->data, s->size);
2911                         s->should_munmap = 0;
2912                         s->data = strbuf_detach(&buf, &size);
2913                         s->size = size;
2914                         s->should_free = 1;
2915                 }
2916         }
2917         else {
2918                 enum object_type type;
2919                 if (size_only || (flags & CHECK_BINARY)) {
2920                         type = sha1_object_info(s->oid.hash, &s->size);
2921                         if (type < 0)
2922                                 die("unable to read %s",
2923                                     oid_to_hex(&s->oid));
2924                         if (size_only)
2925                                 return 0;
2926                         if (s->size > big_file_threshold && s->is_binary == -1) {
2927                                 s->is_binary = 1;
2928                                 return 0;
2929                         }
2930                 }
2931                 s->data = read_sha1_file(s->oid.hash, &type, &s->size);
2932                 if (!s->data)
2933                         die("unable to read %s", oid_to_hex(&s->oid));
2934                 s->should_free = 1;
2935         }
2936         return 0;
2937 }
2938
2939 void diff_free_filespec_blob(struct diff_filespec *s)
2940 {
2941         if (s->should_free)
2942                 free(s->data);
2943         else if (s->should_munmap)
2944                 munmap(s->data, s->size);
2945
2946         if (s->should_free || s->should_munmap) {
2947                 s->should_free = s->should_munmap = 0;
2948                 s->data = NULL;
2949         }
2950 }
2951
2952 void diff_free_filespec_data(struct diff_filespec *s)
2953 {
2954         diff_free_filespec_blob(s);
2955         free(s->cnt_data);
2956         s->cnt_data = NULL;
2957 }
2958
2959 static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
2960                            void *blob,
2961                            unsigned long size,
2962                            const struct object_id *oid,
2963                            int mode)
2964 {
2965         int fd;
2966         struct strbuf buf = STRBUF_INIT;
2967         struct strbuf template = STRBUF_INIT;
2968         char *path_dup = xstrdup(path);
2969         const char *base = basename(path_dup);
2970
2971         /* Generate "XXXXXX_basename.ext" */
2972         strbuf_addstr(&template, "XXXXXX_");
2973         strbuf_addstr(&template, base);
2974
2975         fd = mks_tempfile_ts(&temp->tempfile, template.buf, strlen(base) + 1);
2976         if (fd < 0)
2977                 die_errno("unable to create temp-file");
2978         if (convert_to_working_tree(path,
2979                         (const char *)blob, (size_t)size, &buf)) {
2980                 blob = buf.buf;
2981                 size = buf.len;
2982         }
2983         if (write_in_full(fd, blob, size) != size)
2984                 die_errno("unable to write temp-file");
2985         close_tempfile(&temp->tempfile);
2986         temp->name = get_tempfile_path(&temp->tempfile);
2987         oid_to_hex_r(temp->hex, oid);
2988         xsnprintf(temp->mode, sizeof(temp->mode), "%06o", mode);
2989         strbuf_release(&buf);
2990         strbuf_release(&template);
2991         free(path_dup);
2992 }
2993
2994 static struct diff_tempfile *prepare_temp_file(const char *name,
2995                 struct diff_filespec *one)
2996 {
2997         struct diff_tempfile *temp = claim_diff_tempfile();
2998
2999         if (!DIFF_FILE_VALID(one)) {
3000         not_a_valid_file:
3001                 /* A '-' entry produces this for file-2, and
3002                  * a '+' entry produces this for file-1.
3003                  */
3004                 temp->name = "/dev/null";
3005                 xsnprintf(temp->hex, sizeof(temp->hex), ".");
3006                 xsnprintf(temp->mode, sizeof(temp->mode), ".");
3007                 return temp;
3008         }
3009
3010         if (!S_ISGITLINK(one->mode) &&
3011             (!one->oid_valid ||
3012              reuse_worktree_file(name, &one->oid, 1))) {
3013                 struct stat st;
3014                 if (lstat(name, &st) < 0) {
3015                         if (errno == ENOENT)
3016                                 goto not_a_valid_file;
3017                         die_errno("stat(%s)", name);
3018                 }
3019                 if (S_ISLNK(st.st_mode)) {
3020                         struct strbuf sb = STRBUF_INIT;
3021                         if (strbuf_readlink(&sb, name, st.st_size) < 0)
3022                                 die_errno("readlink(%s)", name);
3023                         prep_temp_blob(name, temp, sb.buf, sb.len,
3024                                        (one->oid_valid ?
3025                                         &one->oid : &null_oid),
3026                                        (one->oid_valid ?
3027                                         one->mode : S_IFLNK));
3028                         strbuf_release(&sb);
3029                 }
3030                 else {
3031                         /* we can borrow from the file in the work tree */
3032                         temp->name = name;
3033                         if (!one->oid_valid)
3034                                 oid_to_hex_r(temp->hex, &null_oid);
3035                         else
3036                                 oid_to_hex_r(temp->hex, &one->oid);
3037                         /* Even though we may sometimes borrow the
3038                          * contents from the work tree, we always want
3039                          * one->mode.  mode is trustworthy even when
3040                          * !(one->oid_valid), as long as
3041                          * DIFF_FILE_VALID(one).
3042                          */
3043                         xsnprintf(temp->mode, sizeof(temp->mode), "%06o", one->mode);
3044                 }
3045                 return temp;
3046         }
3047         else {
3048                 if (diff_populate_filespec(one, 0))
3049                         die("cannot read data blob for %s", one->path);
3050                 prep_temp_blob(name, temp, one->data, one->size,
3051                                &one->oid, one->mode);
3052         }
3053         return temp;
3054 }
3055
3056 static void add_external_diff_name(struct argv_array *argv,
3057                                    const char *name,
3058                                    struct diff_filespec *df)
3059 {
3060         struct diff_tempfile *temp = prepare_temp_file(name, df);
3061         argv_array_push(argv, temp->name);
3062         argv_array_push(argv, temp->hex);
3063         argv_array_push(argv, temp->mode);
3064 }
3065
3066 /* An external diff command takes:
3067  *
3068  * diff-cmd name infile1 infile1-sha1 infile1-mode \
3069  *               infile2 infile2-sha1 infile2-mode [ rename-to ]
3070  *
3071  */
3072 static void run_external_diff(const char *pgm,
3073                               const char *name,
3074                               const char *other,
3075                               struct diff_filespec *one,
3076                               struct diff_filespec *two,
3077                               const char *xfrm_msg,
3078                               int complete_rewrite,
3079                               struct diff_options *o)
3080 {
3081         struct argv_array argv = ARGV_ARRAY_INIT;
3082         struct argv_array env = ARGV_ARRAY_INIT;
3083         struct diff_queue_struct *q = &diff_queued_diff;
3084
3085         argv_array_push(&argv, pgm);
3086         argv_array_push(&argv, name);
3087
3088         if (one && two) {
3089                 add_external_diff_name(&argv, name, one);
3090                 if (!other)
3091                         add_external_diff_name(&argv, name, two);
3092                 else {
3093                         add_external_diff_name(&argv, other, two);
3094                         argv_array_push(&argv, other);
3095                         argv_array_push(&argv, xfrm_msg);
3096                 }
3097         }
3098
3099         argv_array_pushf(&env, "GIT_DIFF_PATH_COUNTER=%d", ++o->diff_path_counter);
3100         argv_array_pushf(&env, "GIT_DIFF_PATH_TOTAL=%d", q->nr);
3101
3102         if (run_command_v_opt_cd_env(argv.argv, RUN_USING_SHELL, NULL, env.argv))
3103                 die(_("external diff died, stopping at %s"), name);
3104
3105         remove_tempfile();
3106         argv_array_clear(&argv);
3107         argv_array_clear(&env);
3108 }
3109
3110 static int similarity_index(struct diff_filepair *p)
3111 {
3112         return p->score * 100 / MAX_SCORE;
3113 }
3114
3115 static const char *diff_abbrev_oid(const struct object_id *oid, int abbrev)
3116 {
3117         if (startup_info->have_repository)
3118                 return find_unique_abbrev(oid->hash, abbrev);
3119         else {
3120                 char *hex = oid_to_hex(oid);
3121                 if (abbrev < 0)
3122                         abbrev = FALLBACK_DEFAULT_ABBREV;
3123                 if (abbrev > GIT_SHA1_HEXSZ)
3124                         die("BUG: oid abbreviation out of range: %d", abbrev);
3125                 if (abbrev)
3126                         hex[abbrev] = '\0';
3127                 return hex;
3128         }
3129 }
3130
3131 static void fill_metainfo(struct strbuf *msg,
3132                           const char *name,
3133                           const char *other,
3134                           struct diff_filespec *one,
3135                           struct diff_filespec *two,
3136                           struct diff_options *o,
3137                           struct diff_filepair *p,
3138                           int *must_show_header,
3139                           int use_color)
3140 {
3141         const char *set = diff_get_color(use_color, DIFF_METAINFO);
3142         const char *reset = diff_get_color(use_color, DIFF_RESET);
3143         const char *line_prefix = diff_line_prefix(o);
3144
3145         *must_show_header = 1;
3146         strbuf_init(msg, PATH_MAX * 2 + 300);
3147         switch (p->status) {
3148         case DIFF_STATUS_COPIED:
3149                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
3150                             line_prefix, set, similarity_index(p));
3151                 strbuf_addf(msg, "%s\n%s%scopy from ",
3152                             reset,  line_prefix, set);
3153                 quote_c_style(name, msg, NULL, 0);
3154                 strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
3155                 quote_c_style(other, msg, NULL, 0);
3156                 strbuf_addf(msg, "%s\n", reset);
3157                 break;
3158         case DIFF_STATUS_RENAMED:
3159                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
3160                             line_prefix, set, similarity_index(p));
3161                 strbuf_addf(msg, "%s\n%s%srename from ",
3162                             reset, line_prefix, set);
3163                 quote_c_style(name, msg, NULL, 0);
3164                 strbuf_addf(msg, "%s\n%s%srename to ",
3165                             reset, line_prefix, set);
3166                 quote_c_style(other, msg, NULL, 0);
3167                 strbuf_addf(msg, "%s\n", reset);
3168                 break;
3169         case DIFF_STATUS_MODIFIED:
3170                 if (p->score) {
3171                         strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
3172                                     line_prefix,
3173                                     set, similarity_index(p), reset);
3174                         break;
3175                 }
3176                 /* fallthru */
3177         default:
3178                 *must_show_header = 0;
3179         }
3180         if (one && two && oidcmp(&one->oid, &two->oid)) {
3181                 int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
3182
3183                 if (DIFF_OPT_TST(o, BINARY)) {
3184                         mmfile_t mf;
3185                         if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
3186                             (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
3187                                 abbrev = 40;
3188                 }
3189                 strbuf_addf(msg, "%s%sindex %s..%s", line_prefix, set,
3190                             diff_abbrev_oid(&one->oid, abbrev),
3191                             diff_abbrev_oid(&two->oid, abbrev));
3192                 if (one->mode == two->mode)
3193                         strbuf_addf(msg, " %06o", one->mode);
3194                 strbuf_addf(msg, "%s\n", reset);
3195         }
3196 }
3197
3198 static void run_diff_cmd(const char *pgm,
3199                          const char *name,
3200                          const char *other,
3201                          const char *attr_path,
3202                          struct diff_filespec *one,
3203                          struct diff_filespec *two,
3204                          struct strbuf *msg,
3205                          struct diff_options *o,
3206                          struct diff_filepair *p)
3207 {
3208         const char *xfrm_msg = NULL;
3209         int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
3210         int must_show_header = 0;
3211
3212
3213         if (DIFF_OPT_TST(o, ALLOW_EXTERNAL)) {
3214                 struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
3215                 if (drv && drv->external)
3216                         pgm = drv->external;
3217         }
3218
3219         if (msg) {
3220                 /*
3221                  * don't use colors when the header is intended for an
3222                  * external diff driver
3223                  */
3224                 fill_metainfo(msg, name, other, one, two, o, p,
3225                               &must_show_header,
3226                               want_color(o->use_color) && !pgm);
3227                 xfrm_msg = msg->len ? msg->buf : NULL;
3228         }
3229
3230         if (pgm) {
3231                 run_external_diff(pgm, name, other, one, two, xfrm_msg,
3232                                   complete_rewrite, o);
3233                 return;
3234         }
3235         if (one && two)
3236                 builtin_diff(name, other ? other : name,
3237                              one, two, xfrm_msg, must_show_header,
3238                              o, complete_rewrite);
3239         else
3240                 fprintf(o->file, "* Unmerged path %s\n", name);
3241 }
3242
3243 static void diff_fill_oid_info(struct diff_filespec *one)
3244 {
3245         if (DIFF_FILE_VALID(one)) {
3246                 if (!one->oid_valid) {
3247                         struct stat st;
3248                         if (one->is_stdin) {
3249                                 oidclr(&one->oid);
3250                                 return;
3251                         }
3252                         if (lstat(one->path, &st) < 0)
3253                                 die_errno("stat '%s'", one->path);
3254                         if (index_path(one->oid.hash, one->path, &st, 0))
3255                                 die("cannot hash %s", one->path);
3256                 }
3257         }
3258         else
3259                 oidclr(&one->oid);
3260 }
3261
3262 static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
3263 {
3264         /* Strip the prefix but do not molest /dev/null and absolute paths */
3265         if (*namep && **namep != '/') {
3266                 *namep += prefix_length;
3267                 if (**namep == '/')
3268                         ++*namep;
3269         }
3270         if (*otherp && **otherp != '/') {
3271                 *otherp += prefix_length;
3272                 if (**otherp == '/')
3273                         ++*otherp;
3274         }
3275 }
3276
3277 static void run_diff(struct diff_filepair *p, struct diff_options *o)
3278 {
3279         const char *pgm = external_diff();
3280         struct strbuf msg;
3281         struct diff_filespec *one = p->one;
3282         struct diff_filespec *two = p->two;
3283         const char *name;
3284         const char *other;
3285         const char *attr_path;
3286
3287         name  = p->one->path;
3288         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3289         attr_path = name;
3290         if (o->prefix_length)
3291                 strip_prefix(o->prefix_length, &name, &other);
3292
3293         if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
3294                 pgm = NULL;
3295
3296         if (DIFF_PAIR_UNMERGED(p)) {
3297                 run_diff_cmd(pgm, name, NULL, attr_path,
3298                              NULL, NULL, NULL, o, p);
3299                 return;
3300         }
3301
3302         diff_fill_oid_info(one);
3303         diff_fill_oid_info(two);
3304
3305         if (!pgm &&
3306             DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
3307             (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
3308                 /*
3309                  * a filepair that changes between file and symlink
3310                  * needs to be split into deletion and creation.
3311                  */
3312                 struct diff_filespec *null = alloc_filespec(two->path);
3313                 run_diff_cmd(NULL, name, other, attr_path,
3314                              one, null, &msg, o, p);
3315                 free(null);
3316                 strbuf_release(&msg);
3317
3318                 null = alloc_filespec(one->path);
3319                 run_diff_cmd(NULL, name, other, attr_path,
3320                              null, two, &msg, o, p);
3321                 free(null);
3322         }
3323         else
3324                 run_diff_cmd(pgm, name, other, attr_path,
3325                              one, two, &msg, o, p);
3326
3327         strbuf_release(&msg);
3328 }
3329
3330 static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
3331                          struct diffstat_t *diffstat)
3332 {
3333         const char *name;
3334         const char *other;
3335
3336         if (DIFF_PAIR_UNMERGED(p)) {
3337                 /* unmerged */
3338                 builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, p);
3339                 return;
3340         }
3341
3342         name = p->one->path;
3343         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3344
3345         if (o->prefix_length)
3346                 strip_prefix(o->prefix_length, &name, &other);
3347
3348         diff_fill_oid_info(p->one);
3349         diff_fill_oid_info(p->two);
3350
3351         builtin_diffstat(name, other, p->one, p->two, diffstat, o, p);
3352 }
3353
3354 static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
3355 {
3356         const char *name;
3357         const char *other;
3358         const char *attr_path;
3359
3360         if (DIFF_PAIR_UNMERGED(p)) {
3361                 /* unmerged */
3362                 return;
3363         }
3364
3365         name = p->one->path;
3366         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3367         attr_path = other ? other : name;
3368
3369         if (o->prefix_length)
3370                 strip_prefix(o->prefix_length, &name, &other);
3371
3372         diff_fill_oid_info(p->one);
3373         diff_fill_oid_info(p->two);
3374
3375         builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
3376 }
3377
3378 void diff_setup(struct diff_options *options)
3379 {
3380         memcpy(options, &default_diff_options, sizeof(*options));
3381
3382         options->file = stdout;
3383
3384         options->abbrev = DEFAULT_ABBREV;
3385         options->line_termination = '\n';
3386         options->break_opt = -1;
3387         options->rename_limit = -1;
3388         options->dirstat_permille = diff_dirstat_permille_default;
3389         options->context = diff_context_default;
3390         options->interhunkcontext = diff_interhunk_context_default;
3391         options->ws_error_highlight = ws_error_highlight_default;
3392         DIFF_OPT_SET(options, RENAME_EMPTY);
3393
3394         /* pathchange left =NULL by default */
3395         options->change = diff_change;
3396         options->add_remove = diff_addremove;
3397         options->use_color = diff_use_color_default;
3398         options->detect_rename = diff_detect_rename_default;
3399         options->xdl_opts |= diff_algorithm;
3400         if (diff_indent_heuristic)
3401                 DIFF_XDL_SET(options, INDENT_HEURISTIC);
3402
3403         options->orderfile = diff_order_file_cfg;
3404
3405         if (diff_no_prefix) {
3406                 options->a_prefix = options->b_prefix = "";
3407         } else if (!diff_mnemonic_prefix) {
3408                 options->a_prefix = "a/";
3409                 options->b_prefix = "b/";
3410         }
3411 }
3412
3413 void diff_setup_done(struct diff_options *options)
3414 {
3415         int count = 0;
3416
3417         if (options->set_default)
3418                 options->set_default(options);
3419
3420         if (options->output_format & DIFF_FORMAT_NAME)
3421                 count++;
3422         if (options->output_format & DIFF_FORMAT_NAME_STATUS)
3423                 count++;
3424         if (options->output_format & DIFF_FORMAT_CHECKDIFF)
3425                 count++;
3426         if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
3427                 count++;
3428         if (count > 1)
3429                 die(_("--name-only, --name-status, --check and -s are mutually exclusive"));
3430
3431         /*
3432          * Most of the time we can say "there are changes"
3433          * only by checking if there are changed paths, but
3434          * --ignore-whitespace* options force us to look
3435          * inside contents.
3436          */
3437
3438         if (DIFF_XDL_TST(options, IGNORE_WHITESPACE) ||
3439             DIFF_XDL_TST(options, IGNORE_WHITESPACE_CHANGE) ||
3440             DIFF_XDL_TST(options, IGNORE_WHITESPACE_AT_EOL))
3441                 DIFF_OPT_SET(options, DIFF_FROM_CONTENTS);
3442         else
3443                 DIFF_OPT_CLR(options, DIFF_FROM_CONTENTS);
3444
3445         if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
3446                 options->detect_rename = DIFF_DETECT_COPY;
3447
3448         if (!DIFF_OPT_TST(options, RELATIVE_NAME))
3449                 options->prefix = NULL;
3450         if (options->prefix)
3451                 options->prefix_length = strlen(options->prefix);
3452         else
3453                 options->prefix_length = 0;
3454
3455         if (options->output_format & (DIFF_FORMAT_NAME |
3456                                       DIFF_FORMAT_NAME_STATUS |
3457                                       DIFF_FORMAT_CHECKDIFF |
3458                                       DIFF_FORMAT_NO_OUTPUT))
3459                 options->output_format &= ~(DIFF_FORMAT_RAW |
3460                                             DIFF_FORMAT_NUMSTAT |
3461                                             DIFF_FORMAT_DIFFSTAT |
3462                                             DIFF_FORMAT_SHORTSTAT |
3463                                             DIFF_FORMAT_DIRSTAT |
3464                                             DIFF_FORMAT_SUMMARY |
3465                                             DIFF_FORMAT_PATCH);
3466
3467         /*
3468          * These cases always need recursive; we do not drop caller-supplied
3469          * recursive bits for other formats here.
3470          */
3471         if (options->output_format & (DIFF_FORMAT_PATCH |
3472                                       DIFF_FORMAT_NUMSTAT |
3473                                       DIFF_FORMAT_DIFFSTAT |
3474                                       DIFF_FORMAT_SHORTSTAT |
3475                                       DIFF_FORMAT_DIRSTAT |
3476                                       DIFF_FORMAT_SUMMARY |
3477                                       DIFF_FORMAT_CHECKDIFF))
3478                 DIFF_OPT_SET(options, RECURSIVE);
3479         /*
3480          * Also pickaxe would not work very well if you do not say recursive
3481          */
3482         if (options->pickaxe)
3483                 DIFF_OPT_SET(options, RECURSIVE);
3484         /*
3485          * When patches are generated, submodules diffed against the work tree
3486          * must be checked for dirtiness too so it can be shown in the output
3487          */
3488         if (options->output_format & DIFF_FORMAT_PATCH)
3489                 DIFF_OPT_SET(options, DIRTY_SUBMODULES);
3490
3491         if (options->detect_rename && options->rename_limit < 0)
3492                 options->rename_limit = diff_rename_limit_default;
3493         if (options->setup & DIFF_SETUP_USE_CACHE) {
3494                 if (!active_cache)
3495                         /* read-cache does not die even when it fails
3496                          * so it is safe for us to do this here.  Also
3497                          * it does not smudge active_cache or active_nr
3498                          * when it fails, so we do not have to worry about
3499                          * cleaning it up ourselves either.
3500                          */
3501                         read_cache();
3502         }
3503         if (40 < options->abbrev)
3504                 options->abbrev = 40; /* full */
3505
3506         /*
3507          * It does not make sense to show the first hit we happened
3508          * to have found.  It does not make sense not to return with
3509          * exit code in such a case either.
3510          */
3511         if (DIFF_OPT_TST(options, QUICK)) {
3512                 options->output_format = DIFF_FORMAT_NO_OUTPUT;
3513                 DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3514         }
3515
3516         options->diff_path_counter = 0;
3517
3518         if (DIFF_OPT_TST(options, FOLLOW_RENAMES) && options->pathspec.nr != 1)
3519                 die(_("--follow requires exactly one pathspec"));
3520 }
3521
3522 static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
3523 {
3524         char c, *eq;
3525         int len;
3526
3527         if (*arg != '-')
3528                 return 0;
3529         c = *++arg;
3530         if (!c)
3531                 return 0;
3532         if (c == arg_short) {
3533                 c = *++arg;
3534                 if (!c)
3535                         return 1;
3536                 if (val && isdigit(c)) {
3537                         char *end;
3538                         int n = strtoul(arg, &end, 10);
3539                         if (*end)
3540                                 return 0;
3541                         *val = n;
3542                         return 1;
3543                 }
3544                 return 0;
3545         }
3546         if (c != '-')
3547                 return 0;
3548         arg++;
3549         eq = strchrnul(arg, '=');
3550         len = eq - arg;
3551         if (!len || strncmp(arg, arg_long, len))
3552                 return 0;
3553         if (*eq) {
3554                 int n;
3555                 char *end;
3556                 if (!isdigit(*++eq))
3557                         return 0;
3558                 n = strtoul(eq, &end, 10);
3559                 if (*end)
3560                         return 0;
3561                 *val = n;
3562         }
3563         return 1;
3564 }
3565
3566 static int diff_scoreopt_parse(const char *opt);
3567
3568 static inline int short_opt(char opt, const char **argv,
3569                             const char **optarg)
3570 {
3571         const char *arg = argv[0];
3572         if (arg[0] != '-' || arg[1] != opt)
3573                 return 0;
3574         if (arg[2] != '\0') {
3575                 *optarg = arg + 2;
3576                 return 1;
3577         }
3578         if (!argv[1])
3579                 die("Option '%c' requires a value", opt);
3580         *optarg = argv[1];
3581         return 2;
3582 }
3583
3584 int parse_long_opt(const char *opt, const char **argv,
3585                    const char **optarg)
3586 {
3587         const char *arg = argv[0];
3588         if (!skip_prefix(arg, "--", &arg))
3589                 return 0;
3590         if (!skip_prefix(arg, opt, &arg))
3591                 return 0;
3592         if (*arg == '=') { /* stuck form: --option=value */
3593                 *optarg = arg + 1;
3594                 return 1;
3595         }
3596         if (*arg != '\0')
3597                 return 0;
3598         /* separate form: --option value */
3599         if (!argv[1])
3600                 die("Option '--%s' requires a value", opt);
3601         *optarg = argv[1];
3602         return 2;
3603 }
3604
3605 static int stat_opt(struct diff_options *options, const char **av)
3606 {
3607         const char *arg = av[0];
3608         char *end;
3609         int width = options->stat_width;
3610         int name_width = options->stat_name_width;
3611         int graph_width = options->stat_graph_width;
3612         int count = options->stat_count;
3613         int argcount = 1;
3614
3615         if (!skip_prefix(arg, "--stat", &arg))
3616                 die("BUG: stat option does not begin with --stat: %s", arg);
3617         end = (char *)arg;
3618
3619         switch (*arg) {
3620         case '-':
3621                 if (skip_prefix(arg, "-width", &arg)) {
3622                         if (*arg == '=')
3623                                 width = strtoul(arg + 1, &end, 10);
3624                         else if (!*arg && !av[1])
3625                                 die_want_option("--stat-width");
3626                         else if (!*arg) {
3627                                 width = strtoul(av[1], &end, 10);
3628                                 argcount = 2;
3629                         }
3630                 } else if (skip_prefix(arg, "-name-width", &arg)) {
3631                         if (*arg == '=')
3632                                 name_width = strtoul(arg + 1, &end, 10);
3633                         else if (!*arg && !av[1])
3634                                 die_want_option("--stat-name-width");
3635                         else if (!*arg) {
3636                                 name_width = strtoul(av[1], &end, 10);
3637                                 argcount = 2;
3638                         }
3639                 } else if (skip_prefix(arg, "-graph-width", &arg)) {
3640                         if (*arg == '=')
3641                                 graph_width = strtoul(arg + 1, &end, 10);
3642                         else if (!*arg && !av[1])
3643                                 die_want_option("--stat-graph-width");
3644                         else if (!*arg) {
3645                                 graph_width = strtoul(av[1], &end, 10);
3646                                 argcount = 2;
3647                         }
3648                 } else if (skip_prefix(arg, "-count", &arg)) {
3649                         if (*arg == '=')
3650                                 count = strtoul(arg + 1, &end, 10);
3651                         else if (!*arg && !av[1])
3652                                 die_want_option("--stat-count");
3653                         else if (!*arg) {
3654                                 count = strtoul(av[1], &end, 10);
3655                                 argcount = 2;
3656                         }
3657                 }
3658                 break;
3659         case '=':
3660                 width = strtoul(arg+1, &end, 10);
3661                 if (*end == ',')
3662                         name_width = strtoul(end+1, &end, 10);
3663                 if (*end == ',')
3664                         count = strtoul(end+1, &end, 10);
3665         }
3666
3667         /* Important! This checks all the error cases! */
3668         if (*end)
3669                 return 0;
3670         options->output_format |= DIFF_FORMAT_DIFFSTAT;
3671         options->stat_name_width = name_width;
3672         options->stat_graph_width = graph_width;
3673         options->stat_width = width;
3674         options->stat_count = count;
3675         return argcount;
3676 }
3677
3678 static int parse_dirstat_opt(struct diff_options *options, const char *params)
3679 {
3680         struct strbuf errmsg = STRBUF_INIT;
3681         if (parse_dirstat_params(options, params, &errmsg))
3682                 die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
3683                     errmsg.buf);
3684         strbuf_release(&errmsg);
3685         /*
3686          * The caller knows a dirstat-related option is given from the command
3687          * line; allow it to say "return this_function();"
3688          */
3689         options->output_format |= DIFF_FORMAT_DIRSTAT;
3690         return 1;
3691 }
3692
3693 static int parse_submodule_opt(struct diff_options *options, const char *value)
3694 {
3695         if (parse_submodule_params(options, value))
3696                 die(_("Failed to parse --submodule option parameter: '%s'"),
3697                         value);
3698         return 1;
3699 }
3700
3701 static const char diff_status_letters[] = {
3702         DIFF_STATUS_ADDED,
3703         DIFF_STATUS_COPIED,
3704         DIFF_STATUS_DELETED,
3705         DIFF_STATUS_MODIFIED,
3706         DIFF_STATUS_RENAMED,
3707         DIFF_STATUS_TYPE_CHANGED,
3708         DIFF_STATUS_UNKNOWN,
3709         DIFF_STATUS_UNMERGED,
3710         DIFF_STATUS_FILTER_AON,
3711         DIFF_STATUS_FILTER_BROKEN,
3712         '\0',
3713 };
3714
3715 static unsigned int filter_bit['Z' + 1];
3716
3717 static void prepare_filter_bits(void)
3718 {
3719         int i;
3720
3721         if (!filter_bit[DIFF_STATUS_ADDED]) {
3722                 for (i = 0; diff_status_letters[i]; i++)
3723                         filter_bit[(int) diff_status_letters[i]] = (1 << i);
3724         }
3725 }
3726
3727 static unsigned filter_bit_tst(char status, const struct diff_options *opt)
3728 {
3729         return opt->filter & filter_bit[(int) status];
3730 }
3731
3732 static int parse_diff_filter_opt(const char *optarg, struct diff_options *opt)
3733 {
3734         int i, optch;
3735
3736         prepare_filter_bits();
3737
3738         /*
3739          * If there is a negation e.g. 'd' in the input, and we haven't
3740          * initialized the filter field with another --diff-filter, start
3741          * from full set of bits, except for AON.
3742          */
3743         if (!opt->filter) {
3744                 for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3745                         if (optch < 'a' || 'z' < optch)
3746                                 continue;
3747                         opt->filter = (1 << (ARRAY_SIZE(diff_status_letters) - 1)) - 1;
3748                         opt->filter &= ~filter_bit[DIFF_STATUS_FILTER_AON];
3749                         break;
3750                 }
3751         }
3752
3753         for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3754                 unsigned int bit;
3755                 int negate;
3756
3757                 if ('a' <= optch && optch <= 'z') {
3758                         negate = 1;
3759                         optch = toupper(optch);
3760                 } else {
3761                         negate = 0;
3762                 }
3763
3764                 bit = (0 <= optch && optch <= 'Z') ? filter_bit[optch] : 0;
3765                 if (!bit)
3766                         return optarg[i];
3767                 if (negate)
3768                         opt->filter &= ~bit;
3769                 else
3770                         opt->filter |= bit;
3771         }
3772         return 0;
3773 }
3774
3775 static void enable_patch_output(int *fmt) {
3776         *fmt &= ~DIFF_FORMAT_NO_OUTPUT;
3777         *fmt |= DIFF_FORMAT_PATCH;
3778 }
3779
3780 static int parse_ws_error_highlight_opt(struct diff_options *opt, const char *arg)
3781 {
3782         int val = parse_ws_error_highlight(arg);
3783
3784         if (val < 0) {
3785                 error("unknown value after ws-error-highlight=%.*s",
3786                       -1 - val, arg);
3787                 return 0;
3788         }
3789         opt->ws_error_highlight = val;
3790         return 1;
3791 }
3792
3793 int diff_opt_parse(struct diff_options *options,
3794                    const char **av, int ac, const char *prefix)
3795 {
3796         const char *arg = av[0];
3797         const char *optarg;
3798         int argcount;
3799
3800         if (!prefix)
3801                 prefix = "";
3802
3803         /* Output format options */
3804         if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch")
3805             || opt_arg(arg, 'U', "unified", &options->context))
3806                 enable_patch_output(&options->output_format);
3807         else if (!strcmp(arg, "--raw"))
3808                 options->output_format |= DIFF_FORMAT_RAW;
3809         else if (!strcmp(arg, "--patch-with-raw")) {
3810                 enable_patch_output(&options->output_format);
3811                 options->output_format |= DIFF_FORMAT_RAW;
3812         } else if (!strcmp(arg, "--numstat"))
3813                 options->output_format |= DIFF_FORMAT_NUMSTAT;
3814         else if (!strcmp(arg, "--shortstat"))
3815                 options->output_format |= DIFF_FORMAT_SHORTSTAT;
3816         else if (!strcmp(arg, "-X") || !strcmp(arg, "--dirstat"))
3817                 return parse_dirstat_opt(options, "");
3818         else if (skip_prefix(arg, "-X", &arg))
3819                 return parse_dirstat_opt(options, arg);
3820         else if (skip_prefix(arg, "--dirstat=", &arg))
3821                 return parse_dirstat_opt(options, arg);
3822         else if (!strcmp(arg, "--cumulative"))
3823                 return parse_dirstat_opt(options, "cumulative");
3824         else if (!strcmp(arg, "--dirstat-by-file"))
3825                 return parse_dirstat_opt(options, "files");
3826         else if (skip_prefix(arg, "--dirstat-by-file=", &arg)) {
3827                 parse_dirstat_opt(options, "files");
3828                 return parse_dirstat_opt(options, arg);
3829         }
3830         else if (!strcmp(arg, "--check"))
3831                 options->output_format |= DIFF_FORMAT_CHECKDIFF;
3832         else if (!strcmp(arg, "--summary"))
3833                 options->output_format |= DIFF_FORMAT_SUMMARY;
3834         else if (!strcmp(arg, "--patch-with-stat")) {
3835                 enable_patch_output(&options->output_format);
3836                 options->output_format |= DIFF_FORMAT_DIFFSTAT;
3837         } else if (!strcmp(arg, "--name-only"))
3838                 options->output_format |= DIFF_FORMAT_NAME;
3839         else if (!strcmp(arg, "--name-status"))
3840                 options->output_format |= DIFF_FORMAT_NAME_STATUS;
3841         else if (!strcmp(arg, "-s") || !strcmp(arg, "--no-patch"))
3842                 options->output_format |= DIFF_FORMAT_NO_OUTPUT;
3843         else if (starts_with(arg, "--stat"))
3844                 /* --stat, --stat-width, --stat-name-width, or --stat-count */
3845                 return stat_opt(options, av);
3846
3847         /* renames options */
3848         else if (starts_with(arg, "-B") || starts_with(arg, "--break-rewrites=") ||
3849                  !strcmp(arg, "--break-rewrites")) {
3850                 if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
3851                         return error("invalid argument to -B: %s", arg+2);
3852         }
3853         else if (starts_with(arg, "-M") || starts_with(arg, "--find-renames=") ||
3854                  !strcmp(arg, "--find-renames")) {
3855                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3856                         return error("invalid argument to -M: %s", arg+2);
3857                 options->detect_rename = DIFF_DETECT_RENAME;
3858         }
3859         else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
3860                 options->irreversible_delete = 1;
3861         }
3862         else if (starts_with(arg, "-C") || starts_with(arg, "--find-copies=") ||
3863                  !strcmp(arg, "--find-copies")) {
3864                 if (options->detect_rename == DIFF_DETECT_COPY)
3865                         DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3866                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3867                         return error("invalid argument to -C: %s", arg+2);
3868                 options->detect_rename = DIFF_DETECT_COPY;
3869         }
3870         else if (!strcmp(arg, "--no-renames"))
3871                 options->detect_rename = 0;
3872         else if (!strcmp(arg, "--rename-empty"))
3873                 DIFF_OPT_SET(options, RENAME_EMPTY);
3874         else if (!strcmp(arg, "--no-rename-empty"))
3875                 DIFF_OPT_CLR(options, RENAME_EMPTY);
3876         else if (!strcmp(arg, "--relative"))
3877                 DIFF_OPT_SET(options, RELATIVE_NAME);
3878         else if (skip_prefix(arg, "--relative=", &arg)) {
3879                 DIFF_OPT_SET(options, RELATIVE_NAME);
3880                 options->prefix = arg;
3881         }
3882
3883         /* xdiff options */
3884         else if (!strcmp(arg, "--minimal"))
3885                 DIFF_XDL_SET(options, NEED_MINIMAL);
3886         else if (!strcmp(arg, "--no-minimal"))
3887                 DIFF_XDL_CLR(options, NEED_MINIMAL);
3888         else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
3889                 DIFF_XDL_SET(options, IGNORE_WHITESPACE);
3890         else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
3891                 DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
3892         else if (!strcmp(arg, "--ignore-space-at-eol"))
3893                 DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
3894         else if (!strcmp(arg, "--ignore-blank-lines"))
3895                 DIFF_XDL_SET(options, IGNORE_BLANK_LINES);
3896         else if (!strcmp(arg, "--indent-heuristic"))
3897                 DIFF_XDL_SET(options, INDENT_HEURISTIC);
3898         else if (!strcmp(arg, "--no-indent-heuristic"))
3899                 DIFF_XDL_CLR(options, INDENT_HEURISTIC);
3900         else if (!strcmp(arg, "--patience"))
3901                 options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
3902         else if (!strcmp(arg, "--histogram"))
3903                 options->xdl_opts = DIFF_WITH_ALG(options, HISTOGRAM_DIFF);
3904         else if ((argcount = parse_long_opt("diff-algorithm", av, &optarg))) {
3905                 long value = parse_algorithm_value(optarg);
3906                 if (value < 0)
3907                         return error("option diff-algorithm accepts \"myers\", "
3908                                      "\"minimal\", \"patience\" and \"histogram\"");
3909                 /* clear out previous settings */
3910                 DIFF_XDL_CLR(options, NEED_MINIMAL);
3911                 options->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
3912                 options->xdl_opts |= value;
3913                 return argcount;
3914         }
3915
3916         /* flags options */
3917         else if (!strcmp(arg, "--binary")) {
3918                 enable_patch_output(&options->output_format);
3919                 DIFF_OPT_SET(options, BINARY);
3920         }
3921         else if (!strcmp(arg, "--full-index"))
3922                 DIFF_OPT_SET(options, FULL_INDEX);
3923         else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
3924                 DIFF_OPT_SET(options, TEXT);
3925         else if (!strcmp(arg, "-R"))
3926                 DIFF_OPT_SET(options, REVERSE_DIFF);
3927         else if (!strcmp(arg, "--find-copies-harder"))
3928                 DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3929         else if (!strcmp(arg, "--follow"))
3930                 DIFF_OPT_SET(options, FOLLOW_RENAMES);
3931         else if (!strcmp(arg, "--no-follow")) {
3932                 DIFF_OPT_CLR(options, FOLLOW_RENAMES);
3933                 DIFF_OPT_CLR(options, DEFAULT_FOLLOW_RENAMES);
3934         } else if (!strcmp(arg, "--color"))
3935                 options->use_color = 1;
3936         else if (skip_prefix(arg, "--color=", &arg)) {
3937                 int value = git_config_colorbool(NULL, arg);
3938                 if (value < 0)
3939                         return error("option `color' expects \"always\", \"auto\", or \"never\"");
3940                 options->use_color = value;
3941         }
3942         else if (!strcmp(arg, "--no-color"))
3943                 options->use_color = 0;
3944         else if (!strcmp(arg, "--color-words")) {
3945                 options->use_color = 1;
3946                 options->word_diff = DIFF_WORDS_COLOR;
3947         }
3948         else if (skip_prefix(arg, "--color-words=", &arg)) {
3949                 options->use_color = 1;
3950                 options->word_diff = DIFF_WORDS_COLOR;
3951                 options->word_regex = arg;
3952         }
3953         else if (!strcmp(arg, "--word-diff")) {
3954                 if (options->word_diff == DIFF_WORDS_NONE)
3955                         options->word_diff = DIFF_WORDS_PLAIN;
3956         }
3957         else if (skip_prefix(arg, "--word-diff=", &arg)) {
3958                 if (!strcmp(arg, "plain"))
3959                         options->word_diff = DIFF_WORDS_PLAIN;
3960                 else if (!strcmp(arg, "color")) {
3961                         options->use_color = 1;
3962                         options->word_diff = DIFF_WORDS_COLOR;
3963                 }
3964                 else if (!strcmp(arg, "porcelain"))
3965                         options->word_diff = DIFF_WORDS_PORCELAIN;
3966                 else if (!strcmp(arg, "none"))
3967                         options->word_diff = DIFF_WORDS_NONE;
3968                 else
3969                         die("bad --word-diff argument: %s", arg);
3970         }
3971         else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
3972                 if (options->word_diff == DIFF_WORDS_NONE)
3973                         options->word_diff = DIFF_WORDS_PLAIN;
3974                 options->word_regex = optarg;
3975                 return argcount;
3976         }
3977         else if (!strcmp(arg, "--exit-code"))
3978                 DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3979         else if (!strcmp(arg, "--quiet"))
3980                 DIFF_OPT_SET(options, QUICK);
3981         else if (!strcmp(arg, "--ext-diff"))
3982                 DIFF_OPT_SET(options, ALLOW_EXTERNAL);
3983         else if (!strcmp(arg, "--no-ext-diff"))
3984                 DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
3985         else if (!strcmp(arg, "--textconv"))
3986                 DIFF_OPT_SET(options, ALLOW_TEXTCONV);
3987         else if (!strcmp(arg, "--no-textconv"))
3988                 DIFF_OPT_CLR(options, ALLOW_TEXTCONV);
3989         else if (!strcmp(arg, "--ignore-submodules")) {
3990                 DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3991                 handle_ignore_submodules_arg(options, "all");
3992         } else if (skip_prefix(arg, "--ignore-submodules=", &arg)) {
3993                 DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3994                 handle_ignore_submodules_arg(options, arg);
3995         } else if (!strcmp(arg, "--submodule"))
3996                 options->submodule_format = DIFF_SUBMODULE_LOG;
3997         else if (skip_prefix(arg, "--submodule=", &arg))
3998                 return parse_submodule_opt(options, arg);
3999         else if (skip_prefix(arg, "--ws-error-highlight=", &arg))
4000                 return parse_ws_error_highlight_opt(options, arg);
4001         else if (!strcmp(arg, "--ita-invisible-in-index"))
4002                 options->ita_invisible_in_index = 1;
4003         else if (!strcmp(arg, "--ita-visible-in-index"))
4004                 options->ita_invisible_in_index = 0;
4005
4006         /* misc options */
4007         else if (!strcmp(arg, "-z"))
4008                 options->line_termination = 0;
4009         else if ((argcount = short_opt('l', av, &optarg))) {
4010                 options->rename_limit = strtoul(optarg, NULL, 10);
4011                 return argcount;
4012         }
4013         else if ((argcount = short_opt('S', av, &optarg))) {
4014                 options->pickaxe = optarg;
4015                 options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
4016                 return argcount;
4017         } else if ((argcount = short_opt('G', av, &optarg))) {
4018                 options->pickaxe = optarg;
4019                 options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
4020                 return argcount;
4021         }
4022         else if (!strcmp(arg, "--pickaxe-all"))
4023                 options->pickaxe_opts |= DIFF_PICKAXE_ALL;
4024         else if (!strcmp(arg, "--pickaxe-regex"))
4025                 options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
4026         else if ((argcount = short_opt('O', av, &optarg))) {
4027                 options->orderfile = prefix_filename(prefix, optarg);
4028                 return argcount;
4029         }
4030         else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
4031                 int offending = parse_diff_filter_opt(optarg, options);
4032                 if (offending)
4033                         die("unknown change class '%c' in --diff-filter=%s",
4034                             offending, optarg);
4035                 return argcount;
4036         }
4037         else if (!strcmp(arg, "--no-abbrev"))
4038                 options->abbrev = 0;
4039         else if (!strcmp(arg, "--abbrev"))
4040                 options->abbrev = DEFAULT_ABBREV;
4041         else if (skip_prefix(arg, "--abbrev=", &arg)) {
4042                 options->abbrev = strtoul(arg, NULL, 10);
4043                 if (options->abbrev < MINIMUM_ABBREV)
4044                         options->abbrev = MINIMUM_ABBREV;
4045                 else if (40 < options->abbrev)
4046                         options->abbrev = 40;
4047         }
4048         else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
4049                 options->a_prefix = optarg;
4050                 return argcount;
4051         }
4052         else if ((argcount = parse_long_opt("line-prefix", av, &optarg))) {
4053                 options->line_prefix = optarg;
4054                 options->line_prefix_length = strlen(options->line_prefix);
4055                 graph_setup_line_prefix(options);
4056                 return argcount;
4057         }
4058         else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
4059                 options->b_prefix = optarg;
4060                 return argcount;
4061         }
4062         else if (!strcmp(arg, "--no-prefix"))
4063                 options->a_prefix = options->b_prefix = "";
4064         else if (opt_arg(arg, '\0', "inter-hunk-context",
4065                          &options->interhunkcontext))
4066                 ;
4067         else if (!strcmp(arg, "-W"))
4068                 DIFF_OPT_SET(options, FUNCCONTEXT);
4069         else if (!strcmp(arg, "--function-context"))
4070                 DIFF_OPT_SET(options, FUNCCONTEXT);
4071         else if (!strcmp(arg, "--no-function-context"))
4072                 DIFF_OPT_CLR(options, FUNCCONTEXT);
4073         else if ((argcount = parse_long_opt("output", av, &optarg))) {
4074                 char *path = prefix_filename(prefix, optarg);
4075                 options->file = xfopen(path, "w");
4076                 options->close_file = 1;
4077                 if (options->use_color != GIT_COLOR_ALWAYS)
4078                         options->use_color = GIT_COLOR_NEVER;
4079                 free(path);
4080                 return argcount;
4081         } else
4082                 return 0;
4083         return 1;
4084 }
4085
4086 int parse_rename_score(const char **cp_p)
4087 {
4088         unsigned long num, scale;
4089         int ch, dot;
4090         const char *cp = *cp_p;
4091
4092         num = 0;
4093         scale = 1;
4094         dot = 0;
4095         for (;;) {
4096                 ch = *cp;
4097                 if ( !dot && ch == '.' ) {
4098                         scale = 1;
4099                         dot = 1;
4100                 } else if ( ch == '%' ) {
4101                         scale = dot ? scale*100 : 100;
4102                         cp++;   /* % is always at the end */
4103                         break;
4104                 } else if ( ch >= '0' && ch <= '9' ) {
4105                         if ( scale < 100000 ) {
4106                                 scale *= 10;
4107                                 num = (num*10) + (ch-'0');
4108                         }
4109                 } else {
4110                         break;
4111                 }
4112                 cp++;
4113         }
4114         *cp_p = cp;
4115
4116         /* user says num divided by scale and we say internally that
4117          * is MAX_SCORE * num / scale.
4118          */
4119         return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
4120 }
4121
4122 static int diff_scoreopt_parse(const char *opt)
4123 {
4124         int opt1, opt2, cmd;
4125
4126         if (*opt++ != '-')
4127                 return -1;
4128         cmd = *opt++;
4129         if (cmd == '-') {
4130                 /* convert the long-form arguments into short-form versions */
4131                 if (skip_prefix(opt, "break-rewrites", &opt)) {
4132                         if (*opt == 0 || *opt++ == '=')
4133                                 cmd = 'B';
4134                 } else if (skip_prefix(opt, "find-copies", &opt)) {
4135                         if (*opt == 0 || *opt++ == '=')
4136                                 cmd = 'C';
4137                 } else if (skip_prefix(opt, "find-renames", &opt)) {
4138                         if (*opt == 0 || *opt++ == '=')
4139                                 cmd = 'M';
4140                 }
4141         }
4142         if (cmd != 'M' && cmd != 'C' && cmd != 'B')
4143                 return -1; /* that is not a -M, -C, or -B option */
4144
4145         opt1 = parse_rename_score(&opt);
4146         if (cmd != 'B')
4147                 opt2 = 0;
4148         else {
4149                 if (*opt == 0)
4150                         opt2 = 0;
4151                 else if (*opt != '/')
4152                         return -1; /* we expect -B80/99 or -B80 */
4153                 else {
4154                         opt++;
4155                         opt2 = parse_rename_score(&opt);
4156                 }
4157         }
4158         if (*opt != 0)
4159                 return -1;
4160         return opt1 | (opt2 << 16);
4161 }
4162
4163 struct diff_queue_struct diff_queued_diff;
4164
4165 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
4166 {
4167         ALLOC_GROW(queue->queue, queue->nr + 1, queue->alloc);
4168         queue->queue[queue->nr++] = dp;
4169 }
4170
4171 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
4172                                  struct diff_filespec *one,
4173                                  struct diff_filespec *two)
4174 {
4175         struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
4176         dp->one = one;
4177         dp->two = two;
4178         if (queue)
4179                 diff_q(queue, dp);
4180         return dp;
4181 }
4182
4183 void diff_free_filepair(struct diff_filepair *p)
4184 {
4185         free_filespec(p->one);
4186         free_filespec(p->two);
4187         free(p);
4188 }
4189
4190 const char *diff_aligned_abbrev(const struct object_id *oid, int len)
4191 {
4192         int abblen;
4193         const char *abbrev;
4194
4195         if (len == GIT_SHA1_HEXSZ)
4196                 return oid_to_hex(oid);
4197
4198         abbrev = diff_abbrev_oid(oid, len);
4199         abblen = strlen(abbrev);
4200
4201         /*
4202          * In well-behaved cases, where the abbbreviated result is the
4203          * same as the requested length, append three dots after the
4204          * abbreviation (hence the whole logic is limited to the case
4205          * where abblen < 37); when the actual abbreviated result is a
4206          * bit longer than the requested length, we reduce the number
4207          * of dots so that they match the well-behaved ones.  However,
4208          * if the actual abbreviation is longer than the requested
4209          * length by more than three, we give up on aligning, and add
4210          * three dots anyway, to indicate that the output is not the
4211          * full object name.  Yes, this may be suboptimal, but this
4212          * appears only in "diff --raw --abbrev" output and it is not
4213          * worth the effort to change it now.  Note that this would
4214          * likely to work fine when the automatic sizing of default
4215          * abbreviation length is used--we would be fed -1 in "len" in
4216          * that case, and will end up always appending three-dots, but
4217          * the automatic sizing is supposed to give abblen that ensures
4218          * uniqueness across all objects (statistically speaking).
4219          */
4220         if (abblen < GIT_SHA1_HEXSZ - 3) {
4221                 static char hex[GIT_MAX_HEXSZ + 1];
4222                 if (len < abblen && abblen <= len + 2)
4223                         xsnprintf(hex, sizeof(hex), "%s%.*s", abbrev, len+3-abblen, "..");
4224                 else
4225                         xsnprintf(hex, sizeof(hex), "%s...", abbrev);
4226                 return hex;
4227         }
4228
4229         return oid_to_hex(oid);
4230 }
4231
4232 static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
4233 {
4234         int line_termination = opt->line_termination;
4235         int inter_name_termination = line_termination ? '\t' : '\0';
4236
4237         fprintf(opt->file, "%s", diff_line_prefix(opt));
4238         if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
4239                 fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
4240                         diff_aligned_abbrev(&p->one->oid, opt->abbrev));
4241                 fprintf(opt->file, "%s ",
4242                         diff_aligned_abbrev(&p->two->oid, opt->abbrev));
4243         }
4244         if (p->score) {
4245                 fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
4246                         inter_name_termination);
4247         } else {
4248                 fprintf(opt->file, "%c%c", p->status, inter_name_termination);
4249         }
4250
4251         if (p->status == DIFF_STATUS_COPIED ||
4252             p->status == DIFF_STATUS_RENAMED) {
4253                 const char *name_a, *name_b;
4254                 name_a = p->one->path;
4255                 name_b = p->two->path;
4256                 strip_prefix(opt->prefix_length, &name_a, &name_b);
4257                 write_name_quoted(name_a, opt->file, inter_name_termination);
4258                 write_name_quoted(name_b, opt->file, line_termination);
4259         } else {
4260                 const char *name_a, *name_b;
4261                 name_a = p->one->mode ? p->one->path : p->two->path;
4262                 name_b = NULL;
4263                 strip_prefix(opt->prefix_length, &name_a, &name_b);
4264                 write_name_quoted(name_a, opt->file, line_termination);
4265         }
4266 }
4267
4268 int diff_unmodified_pair(struct diff_filepair *p)
4269 {
4270         /* This function is written stricter than necessary to support
4271          * the currently implemented transformers, but the idea is to
4272          * let transformers to produce diff_filepairs any way they want,
4273          * and filter and clean them up here before producing the output.
4274          */
4275         struct diff_filespec *one = p->one, *two = p->two;
4276
4277         if (DIFF_PAIR_UNMERGED(p))
4278                 return 0; /* unmerged is interesting */
4279
4280         /* deletion, addition, mode or type change
4281          * and rename are all interesting.
4282          */
4283         if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
4284             DIFF_PAIR_MODE_CHANGED(p) ||
4285             strcmp(one->path, two->path))
4286                 return 0;
4287
4288         /* both are valid and point at the same path.  that is, we are
4289          * dealing with a change.
4290          */
4291         if (one->oid_valid && two->oid_valid &&
4292             !oidcmp(&one->oid, &two->oid) &&
4293             !one->dirty_submodule && !two->dirty_submodule)
4294                 return 1; /* no change */
4295         if (!one->oid_valid && !two->oid_valid)
4296                 return 1; /* both look at the same file on the filesystem. */
4297         return 0;
4298 }
4299
4300 static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
4301 {
4302         if (diff_unmodified_pair(p))
4303                 return;
4304
4305         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4306             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4307                 return; /* no tree diffs in patch format */
4308
4309         run_diff(p, o);
4310 }
4311
4312 static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
4313                             struct diffstat_t *diffstat)
4314 {
4315         if (diff_unmodified_pair(p))
4316                 return;
4317
4318         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4319             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4320                 return; /* no useful stat for tree diffs */
4321
4322         run_diffstat(p, o, diffstat);
4323 }
4324
4325 static void diff_flush_checkdiff(struct diff_filepair *p,
4326                 struct diff_options *o)
4327 {
4328         if (diff_unmodified_pair(p))
4329                 return;
4330
4331         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4332             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4333                 return; /* nothing to check in tree diffs */
4334
4335         run_checkdiff(p, o);
4336 }
4337
4338 int diff_queue_is_empty(void)
4339 {
4340         struct diff_queue_struct *q = &diff_queued_diff;
4341         int i;
4342         for (i = 0; i < q->nr; i++)
4343                 if (!diff_unmodified_pair(q->queue[i]))
4344                         return 0;
4345         return 1;
4346 }
4347
4348 #if DIFF_DEBUG
4349 void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
4350 {
4351         fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
4352                 x, one ? one : "",
4353                 s->path,
4354                 DIFF_FILE_VALID(s) ? "valid" : "invalid",
4355                 s->mode,
4356                 s->oid_valid ? oid_to_hex(&s->oid) : "");
4357         fprintf(stderr, "queue[%d] %s size %lu\n",
4358                 x, one ? one : "",
4359                 s->size);
4360 }
4361
4362 void diff_debug_filepair(const struct diff_filepair *p, int i)
4363 {
4364         diff_debug_filespec(p->one, i, "one");
4365         diff_debug_filespec(p->two, i, "two");
4366         fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
4367                 p->score, p->status ? p->status : '?',
4368                 p->one->rename_used, p->broken_pair);
4369 }
4370
4371 void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
4372 {
4373         int i;
4374         if (msg)
4375                 fprintf(stderr, "%s\n", msg);
4376         fprintf(stderr, "q->nr = %d\n", q->nr);
4377         for (i = 0; i < q->nr; i++) {
4378                 struct diff_filepair *p = q->queue[i];
4379                 diff_debug_filepair(p, i);
4380         }
4381 }
4382 #endif
4383
4384 static void diff_resolve_rename_copy(void)
4385 {
4386         int i;
4387         struct diff_filepair *p;
4388         struct diff_queue_struct *q = &diff_queued_diff;
4389
4390         diff_debug_queue("resolve-rename-copy", q);
4391
4392         for (i = 0; i < q->nr; i++) {
4393                 p = q->queue[i];
4394                 p->status = 0; /* undecided */
4395                 if (DIFF_PAIR_UNMERGED(p))
4396                         p->status = DIFF_STATUS_UNMERGED;
4397                 else if (!DIFF_FILE_VALID(p->one))
4398                         p->status = DIFF_STATUS_ADDED;
4399                 else if (!DIFF_FILE_VALID(p->two))
4400                         p->status = DIFF_STATUS_DELETED;
4401                 else if (DIFF_PAIR_TYPE_CHANGED(p))
4402                         p->status = DIFF_STATUS_TYPE_CHANGED;
4403
4404                 /* from this point on, we are dealing with a pair
4405                  * whose both sides are valid and of the same type, i.e.
4406                  * either in-place edit or rename/copy edit.
4407                  */
4408                 else if (DIFF_PAIR_RENAME(p)) {
4409                         /*
4410                          * A rename might have re-connected a broken
4411                          * pair up, causing the pathnames to be the
4412                          * same again. If so, that's not a rename at
4413                          * all, just a modification..
4414                          *
4415                          * Otherwise, see if this source was used for
4416                          * multiple renames, in which case we decrement
4417                          * the count, and call it a copy.
4418                          */
4419                         if (!strcmp(p->one->path, p->two->path))
4420                                 p->status = DIFF_STATUS_MODIFIED;
4421                         else if (--p->one->rename_used > 0)
4422                                 p->status = DIFF_STATUS_COPIED;
4423                         else
4424                                 p->status = DIFF_STATUS_RENAMED;
4425                 }
4426                 else if (oidcmp(&p->one->oid, &p->two->oid) ||
4427                          p->one->mode != p->two->mode ||
4428                          p->one->dirty_submodule ||
4429                          p->two->dirty_submodule ||
4430                          is_null_oid(&p->one->oid))
4431                         p->status = DIFF_STATUS_MODIFIED;
4432                 else {
4433                         /* This is a "no-change" entry and should not
4434                          * happen anymore, but prepare for broken callers.
4435                          */
4436                         error("feeding unmodified %s to diffcore",
4437                               p->one->path);
4438                         p->status = DIFF_STATUS_UNKNOWN;
4439                 }
4440         }
4441         diff_debug_queue("resolve-rename-copy done", q);
4442 }
4443
4444 static int check_pair_status(struct diff_filepair *p)
4445 {
4446         switch (p->status) {
4447         case DIFF_STATUS_UNKNOWN:
4448                 return 0;
4449         case 0:
4450                 die("internal error in diff-resolve-rename-copy");
4451         default:
4452                 return 1;
4453         }
4454 }
4455
4456 static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
4457 {
4458         int fmt = opt->output_format;
4459
4460         if (fmt & DIFF_FORMAT_CHECKDIFF)
4461                 diff_flush_checkdiff(p, opt);
4462         else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
4463                 diff_flush_raw(p, opt);
4464         else if (fmt & DIFF_FORMAT_NAME) {
4465                 const char *name_a, *name_b;
4466                 name_a = p->two->path;
4467                 name_b = NULL;
4468                 strip_prefix(opt->prefix_length, &name_a, &name_b);
4469                 fprintf(opt->file, "%s", diff_line_prefix(opt));
4470                 write_name_quoted(name_a, opt->file, opt->line_termination);
4471         }
4472 }
4473
4474 static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
4475 {
4476         if (fs->mode)
4477                 fprintf(file, " %s mode %06o ", newdelete, fs->mode);
4478         else
4479                 fprintf(file, " %s ", newdelete);
4480         write_name_quoted(fs->path, file, '\n');
4481 }
4482
4483
4484 static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name,
4485                 const char *line_prefix)
4486 {
4487         if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
4488                 fprintf(file, "%s mode change %06o => %06o%c", line_prefix, p->one->mode,
4489                         p->two->mode, show_name ? ' ' : '\n');
4490                 if (show_name) {
4491                         write_name_quoted(p->two->path, file, '\n');
4492                 }
4493         }
4494 }
4495
4496 static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p,
4497                         const char *line_prefix)
4498 {
4499         char *names = pprint_rename(p->one->path, p->two->path);
4500
4501         fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
4502         free(names);
4503         show_mode_change(file, p, 0, line_prefix);
4504 }
4505
4506 static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
4507 {
4508         FILE *file = opt->file;
4509         const char *line_prefix = diff_line_prefix(opt);
4510
4511         switch(p->status) {
4512         case DIFF_STATUS_DELETED:
4513                 fputs(line_prefix, file);
4514                 show_file_mode_name(file, "delete", p->one);
4515                 break;
4516         case DIFF_STATUS_ADDED:
4517                 fputs(line_prefix, file);
4518                 show_file_mode_name(file, "create", p->two);
4519                 break;
4520         case DIFF_STATUS_COPIED:
4521                 fputs(line_prefix, file);
4522                 show_rename_copy(file, "copy", p, line_prefix);
4523                 break;
4524         case DIFF_STATUS_RENAMED:
4525                 fputs(line_prefix, file);
4526                 show_rename_copy(file, "rename", p, line_prefix);
4527                 break;
4528         default:
4529                 if (p->score) {
4530                         fprintf(file, "%s rewrite ", line_prefix);
4531                         write_name_quoted(p->two->path, file, ' ');
4532                         fprintf(file, "(%d%%)\n", similarity_index(p));
4533                 }
4534                 show_mode_change(file, p, !p->score, line_prefix);
4535                 break;
4536         }
4537 }
4538
4539 struct patch_id_t {
4540         git_SHA_CTX *ctx;
4541         int patchlen;
4542 };
4543
4544 static int remove_space(char *line, int len)
4545 {
4546         int i;
4547         char *dst = line;
4548         unsigned char c;
4549
4550         for (i = 0; i < len; i++)
4551                 if (!isspace((c = line[i])))
4552                         *dst++ = c;
4553
4554         return dst - line;
4555 }
4556
4557 static void patch_id_consume(void *priv, char *line, unsigned long len)
4558 {
4559         struct patch_id_t *data = priv;
4560         int new_len;
4561
4562         /* Ignore line numbers when computing the SHA1 of the patch */
4563         if (starts_with(line, "@@ -"))
4564                 return;
4565
4566         new_len = remove_space(line, len);
4567
4568         git_SHA1_Update(data->ctx, line, new_len);
4569         data->patchlen += new_len;
4570 }
4571
4572 static void patch_id_add_string(git_SHA_CTX *ctx, const char *str)
4573 {
4574         git_SHA1_Update(ctx, str, strlen(str));
4575 }
4576
4577 static void patch_id_add_mode(git_SHA_CTX *ctx, unsigned mode)
4578 {
4579         /* large enough for 2^32 in octal */
4580         char buf[12];
4581         int len = xsnprintf(buf, sizeof(buf), "%06o", mode);
4582         git_SHA1_Update(ctx, buf, len);
4583 }
4584
4585 /* returns 0 upon success, and writes result into sha1 */
4586 static int diff_get_patch_id(struct diff_options *options, struct object_id *oid, int diff_header_only)
4587 {
4588         struct diff_queue_struct *q = &diff_queued_diff;
4589         int i;
4590         git_SHA_CTX ctx;
4591         struct patch_id_t data;
4592
4593         git_SHA1_Init(&ctx);
4594         memset(&data, 0, sizeof(struct patch_id_t));
4595         data.ctx = &ctx;
4596
4597         for (i = 0; i < q->nr; i++) {
4598                 xpparam_t xpp;
4599                 xdemitconf_t xecfg;
4600                 mmfile_t mf1, mf2;
4601                 struct diff_filepair *p = q->queue[i];
4602                 int len1, len2;
4603
4604                 memset(&xpp, 0, sizeof(xpp));
4605                 memset(&xecfg, 0, sizeof(xecfg));
4606                 if (p->status == 0)
4607                         return error("internal diff status error");
4608                 if (p->status == DIFF_STATUS_UNKNOWN)
4609                         continue;
4610                 if (diff_unmodified_pair(p))
4611                         continue;
4612                 if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4613                     (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4614                         continue;
4615                 if (DIFF_PAIR_UNMERGED(p))
4616                         continue;
4617
4618                 diff_fill_oid_info(p->one);
4619                 diff_fill_oid_info(p->two);
4620
4621                 len1 = remove_space(p->one->path, strlen(p->one->path));
4622                 len2 = remove_space(p->two->path, strlen(p->two->path));
4623                 patch_id_add_string(&ctx, "diff--git");
4624                 patch_id_add_string(&ctx, "a/");
4625                 git_SHA1_Update(&ctx, p->one->path, len1);
4626                 patch_id_add_string(&ctx, "b/");
4627                 git_SHA1_Update(&ctx, p->two->path, len2);
4628
4629                 if (p->one->mode == 0) {
4630                         patch_id_add_string(&ctx, "newfilemode");
4631                         patch_id_add_mode(&ctx, p->two->mode);
4632                         patch_id_add_string(&ctx, "---/dev/null");
4633                         patch_id_add_string(&ctx, "+++b/");
4634                         git_SHA1_Update(&ctx, p->two->path, len2);
4635                 } else if (p->two->mode == 0) {
4636                         patch_id_add_string(&ctx, "deletedfilemode");
4637                         patch_id_add_mode(&ctx, p->one->mode);
4638                         patch_id_add_string(&ctx, "---a/");
4639                         git_SHA1_Update(&ctx, p->one->path, len1);
4640                         patch_id_add_string(&ctx, "+++/dev/null");
4641                 } else {
4642                         patch_id_add_string(&ctx, "---a/");
4643                         git_SHA1_Update(&ctx, p->one->path, len1);
4644                         patch_id_add_string(&ctx, "+++b/");
4645                         git_SHA1_Update(&ctx, p->two->path, len2);
4646                 }
4647
4648                 if (diff_header_only)
4649                         continue;
4650
4651                 if (fill_mmfile(&mf1, p->one) < 0 ||
4652                     fill_mmfile(&mf2, p->two) < 0)
4653                         return error("unable to read files to diff");
4654
4655                 if (diff_filespec_is_binary(p->one) ||
4656                     diff_filespec_is_binary(p->two)) {
4657                         git_SHA1_Update(&ctx, oid_to_hex(&p->one->oid),
4658                                         GIT_SHA1_HEXSZ);
4659                         git_SHA1_Update(&ctx, oid_to_hex(&p->two->oid),
4660                                         GIT_SHA1_HEXSZ);
4661                         continue;
4662                 }
4663
4664                 xpp.flags = 0;
4665                 xecfg.ctxlen = 3;
4666                 xecfg.flags = 0;
4667                 if (xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
4668                                   &xpp, &xecfg))
4669                         return error("unable to generate patch-id diff for %s",
4670                                      p->one->path);
4671         }
4672
4673         git_SHA1_Final(oid->hash, &ctx);
4674         return 0;
4675 }
4676
4677 int diff_flush_patch_id(struct diff_options *options, struct object_id *oid, int diff_header_only)
4678 {
4679         struct diff_queue_struct *q = &diff_queued_diff;
4680         int i;
4681         int result = diff_get_patch_id(options, oid, diff_header_only);
4682
4683         for (i = 0; i < q->nr; i++)
4684                 diff_free_filepair(q->queue[i]);
4685
4686         free(q->queue);
4687         DIFF_QUEUE_CLEAR(q);
4688
4689         return result;
4690 }
4691
4692 static int is_summary_empty(const struct diff_queue_struct *q)
4693 {
4694         int i;
4695
4696         for (i = 0; i < q->nr; i++) {
4697                 const struct diff_filepair *p = q->queue[i];
4698
4699                 switch (p->status) {
4700                 case DIFF_STATUS_DELETED:
4701                 case DIFF_STATUS_ADDED:
4702                 case DIFF_STATUS_COPIED:
4703                 case DIFF_STATUS_RENAMED:
4704                         return 0;
4705                 default:
4706                         if (p->score)
4707                                 return 0;
4708                         if (p->one->mode && p->two->mode &&
4709                             p->one->mode != p->two->mode)
4710                                 return 0;
4711                         break;
4712                 }
4713         }
4714         return 1;
4715 }
4716
4717 static const char rename_limit_warning[] =
4718 N_("inexact rename detection was skipped due to too many files.");
4719
4720 static const char degrade_cc_to_c_warning[] =
4721 N_("only found copies from modified paths due to too many files.");
4722
4723 static const char rename_limit_advice[] =
4724 N_("you may want to set your %s variable to at least "
4725    "%d and retry the command.");
4726
4727 void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
4728 {
4729         if (degraded_cc)
4730                 warning(_(degrade_cc_to_c_warning));
4731         else if (needed)
4732                 warning(_(rename_limit_warning));
4733         else
4734                 return;
4735         if (0 < needed && needed < 32767)
4736                 warning(_(rename_limit_advice), varname, needed);
4737 }
4738
4739 void diff_flush(struct diff_options *options)
4740 {
4741         struct diff_queue_struct *q = &diff_queued_diff;
4742         int i, output_format = options->output_format;
4743         int separator = 0;
4744         int dirstat_by_line = 0;
4745
4746         /*
4747          * Order: raw, stat, summary, patch
4748          * or:    name/name-status/checkdiff (other bits clear)
4749          */
4750         if (!q->nr)
4751                 goto free_queue;
4752
4753         if (output_format & (DIFF_FORMAT_RAW |
4754                              DIFF_FORMAT_NAME |
4755                              DIFF_FORMAT_NAME_STATUS |
4756                              DIFF_FORMAT_CHECKDIFF)) {
4757                 for (i = 0; i < q->nr; i++) {
4758                         struct diff_filepair *p = q->queue[i];
4759                         if (check_pair_status(p))
4760                                 flush_one_pair(p, options);
4761                 }
4762                 separator++;
4763         }
4764
4765         if (output_format & DIFF_FORMAT_DIRSTAT && DIFF_OPT_TST(options, DIRSTAT_BY_LINE))
4766                 dirstat_by_line = 1;
4767
4768         if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
4769             dirstat_by_line) {
4770                 struct diffstat_t diffstat;
4771
4772                 memset(&diffstat, 0, sizeof(struct diffstat_t));
4773                 for (i = 0; i < q->nr; i++) {
4774                         struct diff_filepair *p = q->queue[i];
4775                         if (check_pair_status(p))
4776                                 diff_flush_stat(p, options, &diffstat);
4777                 }
4778                 if (output_format & DIFF_FORMAT_NUMSTAT)
4779                         show_numstat(&diffstat, options);
4780                 if (output_format & DIFF_FORMAT_DIFFSTAT)
4781                         show_stats(&diffstat, options);
4782                 if (output_format & DIFF_FORMAT_SHORTSTAT)
4783                         show_shortstats(&diffstat, options);
4784                 if (output_format & DIFF_FORMAT_DIRSTAT && dirstat_by_line)
4785                         show_dirstat_by_line(&diffstat, options);
4786                 free_diffstat_info(&diffstat);
4787                 separator++;
4788         }
4789         if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
4790                 show_dirstat(options);
4791
4792         if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
4793                 for (i = 0; i < q->nr; i++) {
4794                         diff_summary(options, q->queue[i]);
4795                 }
4796                 separator++;
4797         }
4798
4799         if (output_format & DIFF_FORMAT_NO_OUTPUT &&
4800             DIFF_OPT_TST(options, EXIT_WITH_STATUS) &&
4801             DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4802                 /*
4803                  * run diff_flush_patch for the exit status. setting
4804                  * options->file to /dev/null should be safe, because we
4805                  * aren't supposed to produce any output anyway.
4806                  */
4807                 if (options->close_file)
4808                         fclose(options->file);
4809                 options->file = xfopen("/dev/null", "w");
4810                 options->close_file = 1;
4811                 for (i = 0; i < q->nr; i++) {
4812                         struct diff_filepair *p = q->queue[i];
4813                         if (check_pair_status(p))
4814                                 diff_flush_patch(p, options);
4815                         if (options->found_changes)
4816                                 break;
4817                 }
4818         }
4819
4820         if (output_format & DIFF_FORMAT_PATCH) {
4821                 if (separator) {
4822                         fprintf(options->file, "%s%c",
4823                                 diff_line_prefix(options),
4824                                 options->line_termination);
4825                         if (options->stat_sep) {
4826                                 /* attach patch instead of inline */
4827                                 fputs(options->stat_sep, options->file);
4828                         }
4829                 }
4830
4831                 for (i = 0; i < q->nr; i++) {
4832                         struct diff_filepair *p = q->queue[i];
4833                         if (check_pair_status(p))
4834                                 diff_flush_patch(p, options);
4835                 }
4836         }
4837
4838         if (output_format & DIFF_FORMAT_CALLBACK)
4839                 options->format_callback(q, options, options->format_callback_data);
4840
4841         for (i = 0; i < q->nr; i++)
4842                 diff_free_filepair(q->queue[i]);
4843 free_queue:
4844         free(q->queue);
4845         DIFF_QUEUE_CLEAR(q);
4846         if (options->close_file)
4847                 fclose(options->file);
4848
4849         /*
4850          * Report the content-level differences with HAS_CHANGES;
4851          * diff_addremove/diff_change does not set the bit when
4852          * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
4853          */
4854         if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4855                 if (options->found_changes)
4856                         DIFF_OPT_SET(options, HAS_CHANGES);
4857                 else
4858                         DIFF_OPT_CLR(options, HAS_CHANGES);
4859         }
4860 }
4861
4862 static int match_filter(const struct diff_options *options, const struct diff_filepair *p)
4863 {
4864         return (((p->status == DIFF_STATUS_MODIFIED) &&
4865                  ((p->score &&
4866                    filter_bit_tst(DIFF_STATUS_FILTER_BROKEN, options)) ||
4867                   (!p->score &&
4868                    filter_bit_tst(DIFF_STATUS_MODIFIED, options)))) ||
4869                 ((p->status != DIFF_STATUS_MODIFIED) &&
4870                  filter_bit_tst(p->status, options)));
4871 }
4872
4873 static void diffcore_apply_filter(struct diff_options *options)
4874 {
4875         int i;
4876         struct diff_queue_struct *q = &diff_queued_diff;
4877         struct diff_queue_struct outq;
4878
4879         DIFF_QUEUE_CLEAR(&outq);
4880
4881         if (!options->filter)
4882                 return;
4883
4884         if (filter_bit_tst(DIFF_STATUS_FILTER_AON, options)) {
4885                 int found;
4886                 for (i = found = 0; !found && i < q->nr; i++) {
4887                         if (match_filter(options, q->queue[i]))
4888                                 found++;
4889                 }
4890                 if (found)
4891                         return;
4892
4893                 /* otherwise we will clear the whole queue
4894                  * by copying the empty outq at the end of this
4895                  * function, but first clear the current entries
4896                  * in the queue.
4897                  */
4898                 for (i = 0; i < q->nr; i++)
4899                         diff_free_filepair(q->queue[i]);
4900         }
4901         else {
4902                 /* Only the matching ones */
4903                 for (i = 0; i < q->nr; i++) {
4904                         struct diff_filepair *p = q->queue[i];
4905                         if (match_filter(options, p))
4906                                 diff_q(&outq, p);
4907                         else
4908                                 diff_free_filepair(p);
4909                 }
4910         }
4911         free(q->queue);
4912         *q = outq;
4913 }
4914
4915 /* Check whether two filespecs with the same mode and size are identical */
4916 static int diff_filespec_is_identical(struct diff_filespec *one,
4917                                       struct diff_filespec *two)
4918 {
4919         if (S_ISGITLINK(one->mode))
4920                 return 0;
4921         if (diff_populate_filespec(one, 0))
4922                 return 0;
4923         if (diff_populate_filespec(two, 0))
4924                 return 0;
4925         return !memcmp(one->data, two->data, one->size);
4926 }
4927
4928 static int diff_filespec_check_stat_unmatch(struct diff_filepair *p)
4929 {
4930         if (p->done_skip_stat_unmatch)
4931                 return p->skip_stat_unmatch_result;
4932
4933         p->done_skip_stat_unmatch = 1;
4934         p->skip_stat_unmatch_result = 0;
4935         /*
4936          * 1. Entries that come from stat info dirtiness
4937          *    always have both sides (iow, not create/delete),
4938          *    one side of the object name is unknown, with
4939          *    the same mode and size.  Keep the ones that
4940          *    do not match these criteria.  They have real
4941          *    differences.
4942          *
4943          * 2. At this point, the file is known to be modified,
4944          *    with the same mode and size, and the object
4945          *    name of one side is unknown.  Need to inspect
4946          *    the identical contents.
4947          */
4948         if (!DIFF_FILE_VALID(p->one) || /* (1) */
4949             !DIFF_FILE_VALID(p->two) ||
4950             (p->one->oid_valid && p->two->oid_valid) ||
4951             (p->one->mode != p->two->mode) ||
4952             diff_populate_filespec(p->one, CHECK_SIZE_ONLY) ||
4953             diff_populate_filespec(p->two, CHECK_SIZE_ONLY) ||
4954             (p->one->size != p->two->size) ||
4955             !diff_filespec_is_identical(p->one, p->two)) /* (2) */
4956                 p->skip_stat_unmatch_result = 1;
4957         return p->skip_stat_unmatch_result;
4958 }
4959
4960 static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
4961 {
4962         int i;
4963         struct diff_queue_struct *q = &diff_queued_diff;
4964         struct diff_queue_struct outq;
4965         DIFF_QUEUE_CLEAR(&outq);
4966
4967         for (i = 0; i < q->nr; i++) {
4968                 struct diff_filepair *p = q->queue[i];
4969
4970                 if (diff_filespec_check_stat_unmatch(p))
4971                         diff_q(&outq, p);
4972                 else {
4973                         /*
4974                          * The caller can subtract 1 from skip_stat_unmatch
4975                          * to determine how many paths were dirty only
4976                          * due to stat info mismatch.
4977                          */
4978                         if (!DIFF_OPT_TST(diffopt, NO_INDEX))
4979                                 diffopt->skip_stat_unmatch++;
4980                         diff_free_filepair(p);
4981                 }
4982         }
4983         free(q->queue);
4984         *q = outq;
4985 }
4986
4987 static int diffnamecmp(const void *a_, const void *b_)
4988 {
4989         const struct diff_filepair *a = *((const struct diff_filepair **)a_);
4990         const struct diff_filepair *b = *((const struct diff_filepair **)b_);
4991         const char *name_a, *name_b;
4992
4993         name_a = a->one ? a->one->path : a->two->path;
4994         name_b = b->one ? b->one->path : b->two->path;
4995         return strcmp(name_a, name_b);
4996 }
4997
4998 void diffcore_fix_diff_index(struct diff_options *options)
4999 {
5000         struct diff_queue_struct *q = &diff_queued_diff;
5001         QSORT(q->queue, q->nr, diffnamecmp);
5002 }
5003
5004 void diffcore_std(struct diff_options *options)
5005 {
5006         /* NOTE please keep the following in sync with diff_tree_combined() */
5007         if (options->skip_stat_unmatch)
5008                 diffcore_skip_stat_unmatch(options);
5009         if (!options->found_follow) {
5010                 /* See try_to_follow_renames() in tree-diff.c */
5011                 if (options->break_opt != -1)
5012                         diffcore_break(options->break_opt);
5013                 if (options->detect_rename)
5014                         diffcore_rename(options);
5015                 if (options->break_opt != -1)
5016                         diffcore_merge_broken();
5017         }
5018         if (options->pickaxe)
5019                 diffcore_pickaxe(options);
5020         if (options->orderfile)
5021                 diffcore_order(options->orderfile);
5022         if (!options->found_follow)
5023                 /* See try_to_follow_renames() in tree-diff.c */
5024                 diff_resolve_rename_copy();
5025         diffcore_apply_filter(options);
5026
5027         if (diff_queued_diff.nr && !DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
5028                 DIFF_OPT_SET(options, HAS_CHANGES);
5029         else
5030                 DIFF_OPT_CLR(options, HAS_CHANGES);
5031
5032         options->found_follow = 0;
5033 }
5034
5035 int diff_result_code(struct diff_options *opt, int status)
5036 {
5037         int result = 0;
5038
5039         diff_warn_rename_limit("diff.renameLimit",
5040                                opt->needed_rename_limit,
5041                                opt->degraded_cc_to_c);
5042         if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
5043             !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
5044                 return status;
5045         if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
5046             DIFF_OPT_TST(opt, HAS_CHANGES))
5047                 result |= 01;
5048         if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
5049             DIFF_OPT_TST(opt, CHECK_FAILED))
5050                 result |= 02;
5051         return result;
5052 }
5053
5054 int diff_can_quit_early(struct diff_options *opt)
5055 {
5056         return (DIFF_OPT_TST(opt, QUICK) &&
5057                 !opt->filter &&
5058                 DIFF_OPT_TST(opt, HAS_CHANGES));
5059 }
5060
5061 /*
5062  * Shall changes to this submodule be ignored?
5063  *
5064  * Submodule changes can be configured to be ignored separately for each path,
5065  * but that configuration can be overridden from the command line.
5066  */
5067 static int is_submodule_ignored(const char *path, struct diff_options *options)
5068 {
5069         int ignored = 0;
5070         unsigned orig_flags = options->flags;
5071         if (!DIFF_OPT_TST(options, OVERRIDE_SUBMODULE_CONFIG))
5072                 set_diffopt_flags_from_submodule_config(options, path);
5073         if (DIFF_OPT_TST(options, IGNORE_SUBMODULES))
5074                 ignored = 1;
5075         options->flags = orig_flags;
5076         return ignored;
5077 }
5078
5079 void diff_addremove(struct diff_options *options,
5080                     int addremove, unsigned mode,
5081                     const struct object_id *oid,
5082                     int oid_valid,
5083                     const char *concatpath, unsigned dirty_submodule)
5084 {
5085         struct diff_filespec *one, *two;
5086
5087         if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
5088                 return;
5089
5090         /* This may look odd, but it is a preparation for
5091          * feeding "there are unchanged files which should
5092          * not produce diffs, but when you are doing copy
5093          * detection you would need them, so here they are"
5094          * entries to the diff-core.  They will be prefixed
5095          * with something like '=' or '*' (I haven't decided
5096          * which but should not make any difference).
5097          * Feeding the same new and old to diff_change()
5098          * also has the same effect.
5099          * Before the final output happens, they are pruned after
5100          * merged into rename/copy pairs as appropriate.
5101          */
5102         if (DIFF_OPT_TST(options, REVERSE_DIFF))
5103                 addremove = (addremove == '+' ? '-' :
5104                              addremove == '-' ? '+' : addremove);
5105
5106         if (options->prefix &&
5107             strncmp(concatpath, options->prefix, options->prefix_length))
5108                 return;
5109
5110         one = alloc_filespec(concatpath);
5111         two = alloc_filespec(concatpath);
5112
5113         if (addremove != '+')
5114                 fill_filespec(one, oid, oid_valid, mode);
5115         if (addremove != '-') {
5116                 fill_filespec(two, oid, oid_valid, mode);
5117                 two->dirty_submodule = dirty_submodule;
5118         }
5119
5120         diff_queue(&diff_queued_diff, one, two);
5121         if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
5122                 DIFF_OPT_SET(options, HAS_CHANGES);
5123 }
5124
5125 void diff_change(struct diff_options *options,
5126                  unsigned old_mode, unsigned new_mode,
5127                  const struct object_id *old_oid,
5128                  const struct object_id *new_oid,
5129                  int old_oid_valid, int new_oid_valid,
5130                  const char *concatpath,
5131                  unsigned old_dirty_submodule, unsigned new_dirty_submodule)
5132 {
5133         struct diff_filespec *one, *two;
5134         struct diff_filepair *p;
5135
5136         if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
5137             is_submodule_ignored(concatpath, options))
5138                 return;
5139
5140         if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
5141                 SWAP(old_mode, new_mode);
5142                 SWAP(old_oid, new_oid);
5143                 SWAP(old_oid_valid, new_oid_valid);
5144                 SWAP(old_dirty_submodule, new_dirty_submodule);
5145         }
5146
5147         if (options->prefix &&
5148             strncmp(concatpath, options->prefix, options->prefix_length))
5149                 return;
5150
5151         one = alloc_filespec(concatpath);
5152         two = alloc_filespec(concatpath);
5153         fill_filespec(one, old_oid, old_oid_valid, old_mode);
5154         fill_filespec(two, new_oid, new_oid_valid, new_mode);
5155         one->dirty_submodule = old_dirty_submodule;
5156         two->dirty_submodule = new_dirty_submodule;
5157         p = diff_queue(&diff_queued_diff, one, two);
5158
5159         if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
5160                 return;
5161
5162         if (DIFF_OPT_TST(options, QUICK) && options->skip_stat_unmatch &&
5163             !diff_filespec_check_stat_unmatch(p))
5164                 return;
5165
5166         DIFF_OPT_SET(options, HAS_CHANGES);
5167 }
5168
5169 struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
5170 {
5171         struct diff_filepair *pair;
5172         struct diff_filespec *one, *two;
5173
5174         if (options->prefix &&
5175             strncmp(path, options->prefix, options->prefix_length))
5176                 return NULL;
5177
5178         one = alloc_filespec(path);
5179         two = alloc_filespec(path);
5180         pair = diff_queue(&diff_queued_diff, one, two);
5181         pair->is_unmerged = 1;
5182         return pair;
5183 }
5184
5185 static char *run_textconv(const char *pgm, struct diff_filespec *spec,
5186                 size_t *outsize)
5187 {
5188         struct diff_tempfile *temp;
5189         const char *argv[3];
5190         const char **arg = argv;
5191         struct child_process child = CHILD_PROCESS_INIT;
5192         struct strbuf buf = STRBUF_INIT;
5193         int err = 0;
5194
5195         temp = prepare_temp_file(spec->path, spec);
5196         *arg++ = pgm;
5197         *arg++ = temp->name;
5198         *arg = NULL;
5199
5200         child.use_shell = 1;
5201         child.argv = argv;
5202         child.out = -1;
5203         if (start_command(&child)) {
5204                 remove_tempfile();
5205                 return NULL;
5206         }
5207
5208         if (strbuf_read(&buf, child.out, 0) < 0)
5209                 err = error("error reading from textconv command '%s'", pgm);
5210         close(child.out);
5211
5212         if (finish_command(&child) || err) {
5213                 strbuf_release(&buf);
5214                 remove_tempfile();
5215                 return NULL;
5216         }
5217         remove_tempfile();
5218
5219         return strbuf_detach(&buf, outsize);
5220 }
5221
5222 size_t fill_textconv(struct userdiff_driver *driver,
5223                      struct diff_filespec *df,
5224                      char **outbuf)
5225 {
5226         size_t size;
5227
5228         if (!driver) {
5229                 if (!DIFF_FILE_VALID(df)) {
5230                         *outbuf = "";
5231                         return 0;
5232                 }
5233                 if (diff_populate_filespec(df, 0))
5234                         die("unable to read files to diff");
5235                 *outbuf = df->data;
5236                 return df->size;
5237         }
5238
5239         if (!driver->textconv)
5240                 die("BUG: fill_textconv called with non-textconv driver");
5241
5242         if (driver->textconv_cache && df->oid_valid) {
5243                 *outbuf = notes_cache_get(driver->textconv_cache,
5244                                           &df->oid,
5245                                           &size);
5246                 if (*outbuf)
5247                         return size;
5248         }
5249
5250         *outbuf = run_textconv(driver->textconv, df, &size);
5251         if (!*outbuf)
5252                 die("unable to read files to diff");
5253
5254         if (driver->textconv_cache && df->oid_valid) {
5255                 /* ignore errors, as we might be in a readonly repository */
5256                 notes_cache_put(driver->textconv_cache, &df->oid, *outbuf,
5257                                 size);
5258                 /*
5259                  * we could save up changes and flush them all at the end,
5260                  * but we would need an extra call after all diffing is done.
5261                  * Since generating a cache entry is the slow path anyway,
5262                  * this extra overhead probably isn't a big deal.
5263                  */
5264                 notes_cache_write(driver->textconv_cache);
5265         }
5266
5267         return size;
5268 }
5269
5270 int textconv_object(const char *path,
5271                     unsigned mode,
5272                     const struct object_id *oid,
5273                     int oid_valid,
5274                     char **buf,
5275                     unsigned long *buf_size)
5276 {
5277         struct diff_filespec *df;
5278         struct userdiff_driver *textconv;
5279
5280         df = alloc_filespec(path);
5281         fill_filespec(df, oid, oid_valid, mode);
5282         textconv = get_textconv(df);
5283         if (!textconv) {
5284                 free_filespec(df);
5285                 return 0;
5286         }
5287
5288         *buf_size = fill_textconv(textconv, df, buf);
5289         free_filespec(df);
5290         return 1;
5291 }
5292
5293 void setup_diff_pager(struct diff_options *opt)
5294 {
5295         /*
5296          * If the user asked for our exit code, then either they want --quiet
5297          * or --exit-code. We should definitely not bother with a pager in the
5298          * former case, as we will generate no output. Since we still properly
5299          * report our exit code even when a pager is run, we _could_ run a
5300          * pager with --exit-code. But since we have not done so historically,
5301          * and because it is easy to find people oneline advising "git diff
5302          * --exit-code" in hooks and other scripts, we do not do so.
5303          */
5304         if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
5305             check_pager_config("diff") != 0)
5306                 setup_pager();
5307 }