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 "hashmap.h"
  20 #include "ll-merge.h"
  21 #include "string-list.h"
  22 #include "argv-array.h"
  23 #include "graph.h"
  24
  25 #ifdef NO_FAST_WORKING_DIRECTORY
  26 #define FAST_WORKING_DIRECTORY 0
  27 #else
  28 #define FAST_WORKING_DIRECTORY 1
  29 #endif
  30
  31 static int diff_detect_rename_default;
  32 static int diff_indent_heuristic = 1;
  33 static int diff_rename_limit_default = 400;
  34 static int diff_suppress_blank_empty;
  35 static int diff_use_color_default = -1;
  36 static int diff_color_moved_default;
  37 static int diff_context_default = 3;
  38 static int diff_interhunk_context_default;
  39 static const char *diff_word_regex_cfg;
  40 static const char *external_diff_cmd_cfg;
  41 static const char *diff_order_file_cfg;
  42 int diff_auto_refresh_index = 1;
  43 static int diff_mnemonic_prefix;
  44 static int diff_no_prefix;
  45 static int diff_stat_graph_width;
  46 static int diff_dirstat_permille_default = 30;
  47 static struct diff_options default_diff_options;
  48 static long diff_algorithm;
  49 static unsigned ws_error_highlight_default = WSEH_NEW;
  50
  51 static char diff_colors[][COLOR_MAXLEN] = {
  52         GIT_COLOR_RESET,
  53         GIT_COLOR_NORMAL,       /* CONTEXT */
  54         GIT_COLOR_BOLD,         /* METAINFO */
  55         GIT_COLOR_CYAN,         /* FRAGINFO */
  56         GIT_COLOR_RED,          /* OLD */
  57         GIT_COLOR_GREEN,        /* NEW */
  58         GIT_COLOR_YELLOW,       /* COMMIT */
  59         GIT_COLOR_BG_RED,       /* WHITESPACE */
  60         GIT_COLOR_NORMAL,       /* FUNCINFO */
  61         GIT_COLOR_BOLD_MAGENTA, /* OLD_MOVED */
  62         GIT_COLOR_BOLD_BLUE,    /* OLD_MOVED ALTERNATIVE */
  63         GIT_COLOR_FAINT,        /* OLD_MOVED_DIM */
  64         GIT_COLOR_FAINT_ITALIC, /* OLD_MOVED_ALTERNATIVE_DIM */
  65         GIT_COLOR_BOLD_CYAN,    /* NEW_MOVED */
  66         GIT_COLOR_BOLD_YELLOW,  /* NEW_MOVED ALTERNATIVE */
  67         GIT_COLOR_FAINT,        /* NEW_MOVED_DIM */
  68         GIT_COLOR_FAINT_ITALIC, /* NEW_MOVED_ALTERNATIVE_DIM */
  69 };
  70
  71 static NORETURN void die_want_option(const char *option_name)
  72 {
  73         die(_("option '%s' requires a value"), option_name);
  74 }
  75
  76 static int parse_diff_color_slot(const char *var)
  77 {
  78         if (!strcasecmp(var, "context") || !strcasecmp(var, "plain"))
  79                 return DIFF_CONTEXT;
  80         if (!strcasecmp(var, "meta"))
  81                 return DIFF_METAINFO;
  82         if (!strcasecmp(var, "frag"))
  83                 return DIFF_FRAGINFO;
  84         if (!strcasecmp(var, "old"))
  85                 return DIFF_FILE_OLD;
  86         if (!strcasecmp(var, "new"))
  87                 return DIFF_FILE_NEW;
  88         if (!strcasecmp(var, "commit"))
  89                 return DIFF_COMMIT;
  90         if (!strcasecmp(var, "whitespace"))
  91                 return DIFF_WHITESPACE;
  92         if (!strcasecmp(var, "func"))
  93                 return DIFF_FUNCINFO;
  94         if (!strcasecmp(var, "oldmoved"))
  95                 return DIFF_FILE_OLD_MOVED;
  96         if (!strcasecmp(var, "oldmovedalternative"))
  97                 return DIFF_FILE_OLD_MOVED_ALT;
  98         if (!strcasecmp(var, "oldmoveddimmed"))
  99                 return DIFF_FILE_OLD_MOVED_DIM;
 100         if (!strcasecmp(var, "oldmovedalternativedimmed"))
 101                 return DIFF_FILE_OLD_MOVED_ALT_DIM;
 102         if (!strcasecmp(var, "newmoved"))
 103                 return DIFF_FILE_NEW_MOVED;
 104         if (!strcasecmp(var, "newmovedalternative"))
 105                 return DIFF_FILE_NEW_MOVED_ALT;
 106         if (!strcasecmp(var, "newmoveddimmed"))
 107                 return DIFF_FILE_NEW_MOVED_DIM;
 108         if (!strcasecmp(var, "newmovedalternativedimmed"))
 109                 return DIFF_FILE_NEW_MOVED_ALT_DIM;
 110         return -1;
 111 }
 112
 113 static int parse_dirstat_params(struct diff_options *options, const char *params_string,
 114                                 struct strbuf *errmsg)
 115 {
 116         char *params_copy = xstrdup(params_string);
 117         struct string_list params = STRING_LIST_INIT_NODUP;
 118         int ret = 0;
 119         int i;
 120
 121         if (*params_copy)
 122                 string_list_split_in_place(&params, params_copy, ',', -1);
 123         for (i = 0; i < params.nr; i++) {
 124                 const char *p = params.items[i].string;
 125                 if (!strcmp(p, "changes")) {
 126                         DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
 127                         DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
 128                 } else if (!strcmp(p, "lines")) {
 129                         DIFF_OPT_SET(options, DIRSTAT_BY_LINE);
 130                         DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
 131                 } else if (!strcmp(p, "files")) {
 132                         DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
 133                         DIFF_OPT_SET(options, DIRSTAT_BY_FILE);
 134                 } else if (!strcmp(p, "noncumulative")) {
 135                         DIFF_OPT_CLR(options, DIRSTAT_CUMULATIVE);
 136                 } else if (!strcmp(p, "cumulative")) {
 137                         DIFF_OPT_SET(options, DIRSTAT_CUMULATIVE);
 138                 } else if (isdigit(*p)) {
 139                         char *end;
 140                         int permille = strtoul(p, &end, 10) * 10;
 141                         if (*end == '.' && isdigit(*++end)) {
 142                                 /* only use first digit */
 143                                 permille += *end - '0';
 144                                 /* .. and ignore any further digits */
 145                                 while (isdigit(*++end))
 146                                         ; /* nothing */
 147                         }
 148                         if (!*end)
 149                                 options->dirstat_permille = permille;
 150                         else {
 151                                 strbuf_addf(errmsg, _("  Failed to parse dirstat cut-off percentage '%s'\n"),
 152                                             p);
 153                                 ret++;
 154                         }
 155                 } else {
 156                         strbuf_addf(errmsg, _("  Unknown dirstat parameter '%s'\n"), p);
 157                         ret++;
 158                 }
 159
 160         }
 161         string_list_clear(&params, 0);
 162         free(params_copy);
 163         return ret;
 164 }
 165
 166 static int parse_submodule_params(struct diff_options *options, const char *value)
 167 {
 168         if (!strcmp(value, "log"))
 169                 options->submodule_format = DIFF_SUBMODULE_LOG;
 170         else if (!strcmp(value, "short"))
 171                 options->submodule_format = DIFF_SUBMODULE_SHORT;
 172         else if (!strcmp(value, "diff"))
 173                 options->submodule_format = DIFF_SUBMODULE_INLINE_DIFF;
 174         else
 175                 return -1;
 176         return 0;
 177 }
 178
 179 static int git_config_rename(const char *var, const char *value)
 180 {
 181         if (!value)
 182                 return DIFF_DETECT_RENAME;
 183         if (!strcasecmp(value, "copies") || !strcasecmp(value, "copy"))
 184                 return  DIFF_DETECT_COPY;
 185         return git_config_bool(var,value) ? DIFF_DETECT_RENAME : 0;
 186 }
 187
 188 long parse_algorithm_value(const char *value)
 189 {
 190         if (!value)
 191                 return -1;
 192         else if (!strcasecmp(value, "myers") || !strcasecmp(value, "default"))
 193                 return 0;
 194         else if (!strcasecmp(value, "minimal"))
 195                 return XDF_NEED_MINIMAL;
 196         else if (!strcasecmp(value, "patience"))
 197                 return XDF_PATIENCE_DIFF;
 198         else if (!strcasecmp(value, "histogram"))
 199                 return XDF_HISTOGRAM_DIFF;
 200         return -1;
 201 }
 202
 203 static int parse_one_token(const char **arg, const char *token)
 204 {
 205         const char *rest;
 206         if (skip_prefix(*arg, token, &rest) && (!*rest || *rest == ',')) {
 207                 *arg = rest;
 208                 return 1;
 209         }
 210         return 0;
 211 }
 212
 213 static int parse_ws_error_highlight(const char *arg)
 214 {
 215         const char *orig_arg = arg;
 216         unsigned val = 0;
 217
 218         while (*arg) {
 219                 if (parse_one_token(&arg, "none"))
 220                         val = 0;
 221                 else if (parse_one_token(&arg, "default"))
 222                         val = WSEH_NEW;
 223                 else if (parse_one_token(&arg, "all"))
 224                         val = WSEH_NEW | WSEH_OLD | WSEH_CONTEXT;
 225                 else if (parse_one_token(&arg, "new"))
 226                         val |= WSEH_NEW;
 227                 else if (parse_one_token(&arg, "old"))
 228                         val |= WSEH_OLD;
 229                 else if (parse_one_token(&arg, "context"))
 230                         val |= WSEH_CONTEXT;
 231                 else {
 232                         return -1 - (int)(arg - orig_arg);
 233                 }
 234                 if (*arg)
 235                         arg++;
 236         }
 237         return val;
 238 }
 239
 240 /*
 241  * These are to give UI layer defaults.
 242  * The core-level commands such as git-diff-files should
 243  * never be affected by the setting of diff.renames
 244  * the user happens to have in the configuration file.
 245  */
 246 void init_diff_ui_defaults(void)
 247 {
 248         diff_detect_rename_default = 1;
 249 }
 250
 251 int git_diff_heuristic_config(const char *var, const char *value, void *cb)
 252 {
 253         if (!strcmp(var, "diff.indentheuristic"))
 254                 diff_indent_heuristic = git_config_bool(var, value);
 255         return 0;
 256 }
 257
 258 static int parse_color_moved(const char *arg)
 259 {
 260         switch (git_parse_maybe_bool(arg)) {
 261         case 0:
 262                 return COLOR_MOVED_NO;
 263         case 1:
 264                 return COLOR_MOVED_DEFAULT;
 265         default:
 266                 break;
 267         }
 268
 269         if (!strcmp(arg, "no"))
 270                 return COLOR_MOVED_NO;
 271         else if (!strcmp(arg, "plain"))
 272                 return COLOR_MOVED_PLAIN;
 273         else if (!strcmp(arg, "zebra"))
 274                 return COLOR_MOVED_ZEBRA;
 275         else if (!strcmp(arg, "default"))
 276                 return COLOR_MOVED_DEFAULT;
 277         else if (!strcmp(arg, "dimmed_zebra"))
 278                 return COLOR_MOVED_ZEBRA_DIM;
 279         else
 280                 return error(_("color moved setting must be one of 'no', 'default', 'zebra', 'dimmed_zebra', 'plain'"));
 281 }
 282
 283 int git_diff_ui_config(const char *var, const char *value, void *cb)
 284 {
 285         if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 286                 diff_use_color_default = git_config_colorbool(var, value);
 287                 return 0;
 288         }
 289         if (!strcmp(var, "diff.colormoved")) {
 290                 int cm = parse_color_moved(value);
 291                 if (cm < 0)
 292                         return -1;
 293                 diff_color_moved_default = cm;
 294                 return 0;
 295         }
 296         if (!strcmp(var, "diff.context")) {
 297                 diff_context_default = git_config_int(var, value);
 298                 if (diff_context_default < 0)
 299                         return -1;
 300                 return 0;
 301         }
 302         if (!strcmp(var, "diff.interhunkcontext")) {
 303                 diff_interhunk_context_default = git_config_int(var, value);
 304                 if (diff_interhunk_context_default < 0)
 305                         return -1;
 306                 return 0;
 307         }
 308         if (!strcmp(var, "diff.renames")) {
 309                 diff_detect_rename_default = git_config_rename(var, value);
 310                 return 0;
 311         }
 312         if (!strcmp(var, "diff.autorefreshindex")) {
 313                 diff_auto_refresh_index = git_config_bool(var, value);
 314                 return 0;
 315         }
 316         if (!strcmp(var, "diff.mnemonicprefix")) {
 317                 diff_mnemonic_prefix = git_config_bool(var, value);
 318                 return 0;
 319         }
 320         if (!strcmp(var, "diff.noprefix")) {
 321                 diff_no_prefix = git_config_bool(var, value);
 322                 return 0;
 323         }
 324         if (!strcmp(var, "diff.statgraphwidth")) {
 325                 diff_stat_graph_width = git_config_int(var, value);
 326                 return 0;
 327         }
 328         if (!strcmp(var, "diff.external"))
 329                 return git_config_string(&external_diff_cmd_cfg, var, value);
 330         if (!strcmp(var, "diff.wordregex"))
 331                 return git_config_string(&diff_word_regex_cfg, var, value);
 332         if (!strcmp(var, "diff.orderfile"))
 333                 return git_config_pathname(&diff_order_file_cfg, var, value);
 334
 335         if (!strcmp(var, "diff.ignoresubmodules"))
 336                 handle_ignore_submodules_arg(&default_diff_options, value);
 337
 338         if (!strcmp(var, "diff.submodule")) {
 339                 if (parse_submodule_params(&default_diff_options, value))
 340                         warning(_("Unknown value for 'diff.submodule' config variable: '%s'"),
 341                                 value);
 342                 return 0;
 343         }
 344
 345         if (!strcmp(var, "diff.algorithm")) {
 346                 diff_algorithm = parse_algorithm_value(value);
 347                 if (diff_algorithm < 0)
 348                         return -1;
 349                 return 0;
 350         }
 351
 352         if (!strcmp(var, "diff.wserrorhighlight")) {
 353                 int val = parse_ws_error_highlight(value);
 354                 if (val < 0)
 355                         return -1;
 356                 ws_error_highlight_default = val;
 357                 return 0;
 358         }
 359
 360         if (git_color_config(var, value, cb) < 0)
 361                 return -1;
 362
 363         return git_diff_basic_config(var, value, cb);
 364 }
 365
 366 int git_diff_basic_config(const char *var, const char *value, void *cb)
 367 {
 368         const char *name;
 369
 370         if (!strcmp(var, "diff.renamelimit")) {
 371                 diff_rename_limit_default = git_config_int(var, value);
 372                 return 0;
 373         }
 374
 375         if (userdiff_config(var, value) < 0)
 376                 return -1;
 377
 378         if (skip_prefix(var, "diff.color.", &name) ||
 379             skip_prefix(var, "color.diff.", &name)) {
 380                 int slot = parse_diff_color_slot(name);
 381                 if (slot < 0)
 382                         return 0;
 383                 if (!value)
 384                         return config_error_nonbool(var);
 385                 return color_parse(value, diff_colors[slot]);
 386         }
 387
 388         /* like GNU diff's --suppress-blank-empty option  */
 389         if (!strcmp(var, "diff.suppressblankempty") ||
 390                         /* for backwards compatibility */
 391                         !strcmp(var, "diff.suppress-blank-empty")) {
 392                 diff_suppress_blank_empty = git_config_bool(var, value);
 393                 return 0;
 394         }
 395
 396         if (!strcmp(var, "diff.dirstat")) {
 397                 struct strbuf errmsg = STRBUF_INIT;
 398                 default_diff_options.dirstat_permille = diff_dirstat_permille_default;
 399                 if (parse_dirstat_params(&default_diff_options, value, &errmsg))
 400                         warning(_("Found errors in 'diff.dirstat' config variable:\n%s"),
 401                                 errmsg.buf);
 402                 strbuf_release(&errmsg);
 403                 diff_dirstat_permille_default = default_diff_options.dirstat_permille;
 404                 return 0;
 405         }
 406
 407         if (starts_with(var, "submodule."))
 408                 return parse_submodule_config_option(var, value);
 409
 410         if (git_diff_heuristic_config(var, value, cb) < 0)
 411                 return -1;
 412
 413         return git_default_config(var, value, cb);
 414 }
 415
 416 static char *quote_two(const char *one, const char *two)
 417 {
 418         int need_one = quote_c_style(one, NULL, NULL, 1);
 419         int need_two = quote_c_style(two, NULL, NULL, 1);
 420         struct strbuf res = STRBUF_INIT;
 421
 422         if (need_one + need_two) {
 423                 strbuf_addch(&res, '"');
 424                 quote_c_style(one, &res, NULL, 1);
 425                 quote_c_style(two, &res, NULL, 1);
 426                 strbuf_addch(&res, '"');
 427         } else {
 428                 strbuf_addstr(&res, one);
 429                 strbuf_addstr(&res, two);
 430         }
 431         return strbuf_detach(&res, NULL);
 432 }
 433
 434 static const char *external_diff(void)
 435 {
 436         static const char *external_diff_cmd = NULL;
 437         static int done_preparing = 0;
 438
 439         if (done_preparing)
 440                 return external_diff_cmd;
 441         external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 442         if (!external_diff_cmd)
 443                 external_diff_cmd = external_diff_cmd_cfg;
 444         done_preparing = 1;
 445         return external_diff_cmd;
 446 }
 447
 448 /*
 449  * Keep track of files used for diffing. Sometimes such an entry
 450  * refers to a temporary file, sometimes to an existing file, and
 451  * sometimes to "/dev/null".
 452  */
 453 static struct diff_tempfile {
 454         /*
 455          * filename external diff should read from, or NULL if this
 456          * entry is currently not in use:
 457          */
 458         const char *name;
 459
 460         char hex[GIT_MAX_HEXSZ + 1];
 461         char mode[10];
 462
 463         /*
 464          * If this diff_tempfile instance refers to a temporary file,
 465          * this tempfile object is used to manage its lifetime.
 466          */
 467         struct tempfile tempfile;
 468 } diff_temp[2];
 469
 470 typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
 471
 472 struct emit_callback {
 473         int color_diff;
 474         unsigned ws_rule;
 475         int blank_at_eof_in_preimage;
 476         int blank_at_eof_in_postimage;
 477         int lno_in_preimage;
 478         int lno_in_postimage;
 479         sane_truncate_fn truncate;
 480         const char **label_path;
 481         struct diff_words_data *diff_words;
 482         struct diff_options *opt;
 483         struct strbuf *header;
 484 };
 485
 486 static int count_lines(const char *data, int size)
 487 {
 488         int count, ch, completely_empty = 1, nl_just_seen = 0;
 489         count = 0;
 490         while (0 < size--) {
 491                 ch = *data++;
 492                 if (ch == '\n') {
 493                         count++;
 494                         nl_just_seen = 1;
 495                         completely_empty = 0;
 496                 }
 497                 else {
 498                         nl_just_seen = 0;
 499                         completely_empty = 0;
 500                 }
 501         }
 502         if (completely_empty)
 503                 return 0;
 504         if (!nl_just_seen)
 505                 count++; /* no trailing newline */
 506         return count;
 507 }
 508
 509 static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 510 {
 511         if (!DIFF_FILE_VALID(one)) {
 512                 mf->ptr = (char *)""; /* does not matter */
 513                 mf->size = 0;
 514                 return 0;
 515         }
 516         else if (diff_populate_filespec(one, 0))
 517                 return -1;
 518
 519         mf->ptr = one->data;
 520         mf->size = one->size;
 521         return 0;
 522 }
 523
 524 /* like fill_mmfile, but only for size, so we can avoid retrieving blob */
 525 static unsigned long diff_filespec_size(struct diff_filespec *one)
 526 {
 527         if (!DIFF_FILE_VALID(one))
 528                 return 0;
 529         diff_populate_filespec(one, CHECK_SIZE_ONLY);
 530         return one->size;
 531 }
 532
 533 static int count_trailing_blank(mmfile_t *mf, unsigned ws_rule)
 534 {
 535         char *ptr = mf->ptr;
 536         long size = mf->size;
 537         int cnt = 0;
 538
 539         if (!size)
 540                 return cnt;
 541         ptr += size - 1; /* pointing at the very end */
 542         if (*ptr != '\n')
 543                 ; /* incomplete line */
 544         else
 545                 ptr--; /* skip the last LF */
 546         while (mf->ptr < ptr) {
 547                 char *prev_eol;
 548                 for (prev_eol = ptr; mf->ptr <= prev_eol; prev_eol--)
 549                         if (*prev_eol == '\n')
 550                                 break;
 551                 if (!ws_blank_line(prev_eol + 1, ptr - prev_eol, ws_rule))
 552                         break;
 553                 cnt++;
 554                 ptr = prev_eol - 1;
 555         }
 556         return cnt;
 557 }
 558
 559 static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
 560                                struct emit_callback *ecbdata)
 561 {
 562         int l1, l2, at;
 563         unsigned ws_rule = ecbdata->ws_rule;
 564         l1 = count_trailing_blank(mf1, ws_rule);
 565         l2 = count_trailing_blank(mf2, ws_rule);
 566         if (l2 <= l1) {
 567                 ecbdata->blank_at_eof_in_preimage = 0;
 568                 ecbdata->blank_at_eof_in_postimage = 0;
 569                 return;
 570         }
 571         at = count_lines(mf1->ptr, mf1->size);
 572         ecbdata->blank_at_eof_in_preimage = (at - l1) + 1;
 573
 574         at = count_lines(mf2->ptr, mf2->size);
 575         ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
 576 }
 577
 578 static void emit_line_0(struct diff_options *o, const char *set, const char *reset,
 579                         int first, const char *line, int len)
 580 {
 581         int has_trailing_newline, has_trailing_carriage_return;
 582         int nofirst;
 583         FILE *file = o->file;
 584
 585         fputs(diff_line_prefix(o), file);
 586
 587         if (len == 0) {
 588                 has_trailing_newline = (first == '\n');
 589                 has_trailing_carriage_return = (!has_trailing_newline &&
 590                                                 (first == '\r'));
 591                 nofirst = has_trailing_newline || has_trailing_carriage_return;
 592         } else {
 593                 has_trailing_newline = (len > 0 && line[len-1] == '\n');
 594                 if (has_trailing_newline)
 595                         len--;
 596                 has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
 597                 if (has_trailing_carriage_return)
 598                         len--;
 599                 nofirst = 0;
 600         }
 601
 602         if (len || !nofirst) {
 603                 fputs(set, file);
 604                 if (!nofirst)
 605                         fputc(first, file);
 606                 fwrite(line, len, 1, file);
 607                 fputs(reset, file);
 608         }
 609         if (has_trailing_carriage_return)
 610                 fputc('\r', file);
 611         if (has_trailing_newline)
 612                 fputc('\n', file);
 613 }
 614
 615 static void emit_line(struct diff_options *o, const char *set, const char *reset,
 616                       const char *line, int len)
 617 {
 618         emit_line_0(o, set, reset, line[0], line+1, len-1);
 619 }
 620
 621 enum diff_symbol {
 622         DIFF_SYMBOL_BINARY_DIFF_HEADER,
 623         DIFF_SYMBOL_BINARY_DIFF_HEADER_DELTA,
 624         DIFF_SYMBOL_BINARY_DIFF_HEADER_LITERAL,
 625         DIFF_SYMBOL_BINARY_DIFF_BODY,
 626         DIFF_SYMBOL_BINARY_DIFF_FOOTER,
 627         DIFF_SYMBOL_STATS_SUMMARY_NO_FILES,
 628         DIFF_SYMBOL_STATS_SUMMARY_ABBREV,
 629         DIFF_SYMBOL_STATS_SUMMARY_INSERTS_DELETES,
 630         DIFF_SYMBOL_STATS_LINE,
 631         DIFF_SYMBOL_WORD_DIFF,
 632         DIFF_SYMBOL_STAT_SEP,
 633         DIFF_SYMBOL_SUMMARY,
 634         DIFF_SYMBOL_SUBMODULE_ADD,
 635         DIFF_SYMBOL_SUBMODULE_DEL,
 636         DIFF_SYMBOL_SUBMODULE_UNTRACKED,
 637         DIFF_SYMBOL_SUBMODULE_MODIFIED,
 638         DIFF_SYMBOL_SUBMODULE_HEADER,
 639         DIFF_SYMBOL_SUBMODULE_ERROR,
 640         DIFF_SYMBOL_SUBMODULE_PIPETHROUGH,
 641         DIFF_SYMBOL_REWRITE_DIFF,
 642         DIFF_SYMBOL_BINARY_FILES,
 643         DIFF_SYMBOL_HEADER,
 644         DIFF_SYMBOL_FILEPAIR_PLUS,
 645         DIFF_SYMBOL_FILEPAIR_MINUS,
 646         DIFF_SYMBOL_WORDS_PORCELAIN,
 647         DIFF_SYMBOL_WORDS,
 648         DIFF_SYMBOL_CONTEXT,
 649         DIFF_SYMBOL_CONTEXT_INCOMPLETE,
 650         DIFF_SYMBOL_PLUS,
 651         DIFF_SYMBOL_MINUS,
 652         DIFF_SYMBOL_NO_LF_EOF,
 653         DIFF_SYMBOL_CONTEXT_FRAGINFO,
 654         DIFF_SYMBOL_CONTEXT_MARKER,
 655         DIFF_SYMBOL_SEPARATOR
 656 };
 657 /*
 658  * Flags for content lines:
 659  * 0..12 are whitespace rules
 660  * 13-15 are WSEH_NEW | WSEH_OLD | WSEH_CONTEXT
 661  * 16 is marking if the line is blank at EOF
 662  */
 663 #define DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF      (1<<16)
 664 #define DIFF_SYMBOL_MOVED_LINE                  (1<<17)
 665 #define DIFF_SYMBOL_MOVED_LINE_ALT              (1<<18)
 666 #define DIFF_SYMBOL_MOVED_LINE_UNINTERESTING    (1<<19)
 667 #define DIFF_SYMBOL_CONTENT_WS_MASK (WSEH_NEW | WSEH_OLD | WSEH_CONTEXT | WS_RULE_MASK)
 668
 669 /*
 670  * This struct is used when we need to buffer the output of the diff output.
 671  *
 672  * NEEDSWORK: Instead of storing a copy of the line, add an offset pointer
 673  * into the pre/post image file. This pointer could be a union with the
 674  * line pointer. By storing an offset into the file instead of the literal line,
 675  * we can decrease the memory footprint for the buffered output. At first we
 676  * may want to only have indirection for the content lines, but we could also
 677  * enhance the state for emitting prefabricated lines, e.g. the similarity
 678  * score line or hunk/file headers would only need to store a number or path
 679  * and then the output can be constructed later on depending on state.
 680  */
 681 struct emitted_diff_symbol {
 682         const char *line;
 683         int len;
 684         int flags;
 685         enum diff_symbol s;
 686 };
 687 #define EMITTED_DIFF_SYMBOL_INIT {NULL}
 688
 689 struct emitted_diff_symbols {
 690         struct emitted_diff_symbol *buf;
 691         int nr, alloc;
 692 };
 693 #define EMITTED_DIFF_SYMBOLS_INIT {NULL, 0, 0}
 694
 695 static void append_emitted_diff_symbol(struct diff_options *o,
 696                                        struct emitted_diff_symbol *e)
 697 {
 698         struct emitted_diff_symbol *f;
 699
 700         ALLOC_GROW(o->emitted_symbols->buf,
 701                    o->emitted_symbols->nr + 1,
 702                    o->emitted_symbols->alloc);
 703         f = &o->emitted_symbols->buf[o->emitted_symbols->nr++];
 704
 705         memcpy(f, e, sizeof(struct emitted_diff_symbol));
 706         f->line = e->line ? xmemdupz(e->line, e->len) : NULL;
 707 }
 708
 709 struct moved_entry {
 710         struct hashmap_entry ent;
 711         const struct emitted_diff_symbol *es;
 712         struct moved_entry *next_line;
 713 };
 714
 715 static int next_byte(const char **cp, const char **endp,
 716                      const struct diff_options *diffopt)
 717 {
 718         int retval;
 719
 720         if (*cp > *endp)
 721                 return -1;
 722
 723         if (DIFF_XDL_TST(diffopt, IGNORE_WHITESPACE_CHANGE)) {
 724                 while (*cp < *endp && isspace(**cp))
 725                         (*cp)++;
 726                 /*
 727                  * After skipping a couple of whitespaces, we still have to
 728                  * account for one space.
 729                  */
 730                 return (int)' ';
 731         }
 732
 733         if (DIFF_XDL_TST(diffopt, IGNORE_WHITESPACE)) {
 734                 while (*cp < *endp && isspace(**cp))
 735                         (*cp)++;
 736                 /* return the first non-ws character via the usual below */
 737         }
 738
 739         retval = (unsigned char)(**cp);
 740         (*cp)++;
 741         return retval;
 742 }
 743
 744 static int moved_entry_cmp(const struct diff_options *diffopt,
 745                            const struct moved_entry *a,
 746                            const struct moved_entry *b,
 747                            const void *keydata)
 748 {
 749         const char *ap = a->es->line, *ae = a->es->line + a->es->len;
 750         const char *bp = b->es->line, *be = b->es->line + b->es->len;
 751
 752         if (!(diffopt->xdl_opts & XDF_WHITESPACE_FLAGS))
 753                 return a->es->len != b->es->len  || memcmp(ap, bp, a->es->len);
 754
 755         if (DIFF_XDL_TST(diffopt, IGNORE_WHITESPACE_AT_EOL)) {
 756                 while (ae > ap && isspace(*ae))
 757                         ae--;
 758                 while (be > bp && isspace(*be))
 759                         be--;
 760         }
 761
 762         while (1) {
 763                 int ca, cb;
 764                 ca = next_byte(&ap, &ae, diffopt);
 765                 cb = next_byte(&bp, &be, diffopt);
 766                 if (ca != cb)
 767                         return 1;
 768                 if (ca < 0)
 769                         return 0;
 770         }
 771 }
 772
 773 static unsigned get_string_hash(struct emitted_diff_symbol *es, struct diff_options *o)
 774 {
 775         if (o->xdl_opts & XDF_WHITESPACE_FLAGS) {
 776                 static struct strbuf sb = STRBUF_INIT;
 777                 const char *ap = es->line, *ae = es->line + es->len;
 778                 int c;
 779
 780                 strbuf_reset(&sb);
 781                 while (ae > ap && isspace(*ae))
 782                         ae--;
 783                 while ((c = next_byte(&ap, &ae, o)) > 0)
 784                         strbuf_addch(&sb, c);
 785
 786                 return memhash(sb.buf, sb.len);
 787         } else {
 788                 return memhash(es->line, es->len);
 789         }
 790 }
 791
 792 static struct moved_entry *prepare_entry(struct diff_options *o,
 793                                          int line_no)
 794 {
 795         struct moved_entry *ret = xmalloc(sizeof(*ret));
 796         struct emitted_diff_symbol *l = &o->emitted_symbols->buf[line_no];
 797
 798         ret->ent.hash = get_string_hash(l, o);
 799         ret->es = l;
 800         ret->next_line = NULL;
 801
 802         return ret;
 803 }
 804
 805 static void add_lines_to_move_detection(struct diff_options *o,
 806                                         struct hashmap *add_lines,
 807                                         struct hashmap *del_lines)
 808 {
 809         struct moved_entry *prev_line = NULL;
 810
 811         int n;
 812         for (n = 0; n < o->emitted_symbols->nr; n++) {
 813                 struct hashmap *hm;
 814                 struct moved_entry *key;
 815
 816                 switch (o->emitted_symbols->buf[n].s) {
 817                 case DIFF_SYMBOL_PLUS:
 818                         hm = add_lines;
 819                         break;
 820                 case DIFF_SYMBOL_MINUS:
 821                         hm = del_lines;
 822                         break;
 823                 default:
 824                         prev_line = NULL;
 825                         continue;
 826                 }
 827
 828                 key = prepare_entry(o, n);
 829                 if (prev_line && prev_line->es->s == o->emitted_symbols->buf[n].s)
 830                         prev_line->next_line = key;
 831
 832                 hashmap_add(hm, key);
 833                 prev_line = key;
 834         }
 835 }
 836
 837 static int shrink_potential_moved_blocks(struct moved_entry **pmb,
 838                                          int pmb_nr)
 839 {
 840         int lp, rp;
 841
 842         /* Shrink the set of potential block to the remaining running */
 843         for (lp = 0, rp = pmb_nr - 1; lp <= rp;) {
 844                 while (lp < pmb_nr && pmb[lp])
 845                         lp++;
 846                 /* lp points at the first NULL now */
 847
 848                 while (rp > -1 && !pmb[rp])
 849                         rp--;
 850                 /* rp points at the last non-NULL */
 851
 852                 if (lp < pmb_nr && rp > -1 && lp < rp) {
 853                         pmb[lp] = pmb[rp];
 854                         pmb[rp] = NULL;
 855                         rp--;
 856                         lp++;
 857                 }
 858         }
 859
 860         /* Remember the number of running sets */
 861         return rp + 1;
 862 }
 863
 864 /*
 865  * If o->color_moved is COLOR_MOVED_PLAIN, this function does nothing.
 866  *
 867  * Otherwise, if the last block has fewer alphanumeric characters than
 868  * COLOR_MOVED_MIN_ALNUM_COUNT, unset DIFF_SYMBOL_MOVED_LINE on all lines in
 869  * that block.
 870  *
 871  * The last block consists of the (n - block_length)'th line up to but not
 872  * including the nth line.
 873  *
 874  * NEEDSWORK: This uses the same heuristic as blame_entry_score() in blame.c.
 875  * Think of a way to unify them.
 876  */
 877 static void adjust_last_block(struct diff_options *o, int n, int block_length)
 878 {
 879         int i, alnum_count = 0;
 880         if (o->color_moved == COLOR_MOVED_PLAIN)
 881                 return;
 882         for (i = 1; i < block_length + 1; i++) {
 883                 const char *c = o->emitted_symbols->buf[n - i].line;
 884                 for (; *c; c++) {
 885                         if (!isalnum(*c))
 886                                 continue;
 887                         alnum_count++;
 888                         if (alnum_count >= COLOR_MOVED_MIN_ALNUM_COUNT)
 889                                 return;
 890                 }
 891         }
 892         for (i = 1; i < block_length + 1; i++)
 893                 o->emitted_symbols->buf[n - i].flags &= ~DIFF_SYMBOL_MOVED_LINE;
 894 }
 895
 896 /* Find blocks of moved code, delegate actual coloring decision to helper */
 897 static void mark_color_as_moved(struct diff_options *o,
 898                                 struct hashmap *add_lines,
 899                                 struct hashmap *del_lines)
 900 {
 901         struct moved_entry **pmb = NULL; /* potentially moved blocks */
 902         int pmb_nr = 0, pmb_alloc = 0;
 903         int n, flipped_block = 1, block_length = 0;
 904
 905
 906         for (n = 0; n < o->emitted_symbols->nr; n++) {
 907                 struct hashmap *hm = NULL;
 908                 struct moved_entry *key;
 909                 struct moved_entry *match = NULL;
 910                 struct emitted_diff_symbol *l = &o->emitted_symbols->buf[n];
 911                 int i;
 912
 913                 switch (l->s) {
 914                 case DIFF_SYMBOL_PLUS:
 915                         hm = del_lines;
 916                         key = prepare_entry(o, n);
 917                         match = hashmap_get(hm, key, o);
 918                         free(key);
 919                         break;
 920                 case DIFF_SYMBOL_MINUS:
 921                         hm = add_lines;
 922                         key = prepare_entry(o, n);
 923                         match = hashmap_get(hm, key, o);
 924                         free(key);
 925                         break;
 926                 default:
 927                         flipped_block = 1;
 928                 }
 929
 930                 if (!match) {
 931                         adjust_last_block(o, n, block_length);
 932                         pmb_nr = 0;
 933                         block_length = 0;
 934                         continue;
 935                 }
 936
 937                 l->flags |= DIFF_SYMBOL_MOVED_LINE;
 938
 939                 if (o->color_moved == COLOR_MOVED_PLAIN)
 940                         continue;
 941
 942                 /* Check any potential block runs, advance each or nullify */
 943                 for (i = 0; i < pmb_nr; i++) {
 944                         struct moved_entry *p = pmb[i];
 945                         struct moved_entry *pnext = (p && p->next_line) ?
 946                                         p->next_line : NULL;
 947                         if (pnext && !hm->cmpfn(o, pnext, match, NULL)) {
 948                                 pmb[i] = p->next_line;
 949                         } else {
 950                                 pmb[i] = NULL;
 951                         }
 952                 }
 953
 954                 pmb_nr = shrink_potential_moved_blocks(pmb, pmb_nr);
 955
 956                 if (pmb_nr == 0) {
 957                         /*
 958                          * The current line is the start of a new block.
 959                          * Setup the set of potential blocks.
 960                          */
 961                         for (; match; match = hashmap_get_next(hm, match)) {
 962                                 ALLOC_GROW(pmb, pmb_nr + 1, pmb_alloc);
 963                                 pmb[pmb_nr++] = match;
 964                         }
 965
 966                         flipped_block = (flipped_block + 1) % 2;
 967
 968                         adjust_last_block(o, n, block_length);
 969                         block_length = 0;
 970                 }
 971
 972                 block_length++;
 973
 974                 if (flipped_block)
 975                         l->flags |= DIFF_SYMBOL_MOVED_LINE_ALT;
 976         }
 977         adjust_last_block(o, n, block_length);
 978
 979         free(pmb);
 980 }
 981
 982 #define DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK \
 983   (DIFF_SYMBOL_MOVED_LINE | DIFF_SYMBOL_MOVED_LINE_ALT)
 984 static void dim_moved_lines(struct diff_options *o)
 985 {
 986         int n;
 987         for (n = 0; n < o->emitted_symbols->nr; n++) {
 988                 struct emitted_diff_symbol *prev = (n != 0) ?
 989                                 &o->emitted_symbols->buf[n - 1] : NULL;
 990                 struct emitted_diff_symbol *l = &o->emitted_symbols->buf[n];
 991                 struct emitted_diff_symbol *next =
 992                                 (n < o->emitted_symbols->nr - 1) ?
 993                                 &o->emitted_symbols->buf[n + 1] : NULL;
 994
 995                 /* Not a plus or minus line? */
 996                 if (l->s != DIFF_SYMBOL_PLUS && l->s != DIFF_SYMBOL_MINUS)
 997                         continue;
 998
 999                 /* Not a moved line? */
1000                 if (!(l->flags & DIFF_SYMBOL_MOVED_LINE))
1001                         continue;
1002
1003                 /*
1004                  * If prev or next are not a plus or minus line,
1005                  * pretend they don't exist
1006                  */
1007                 if (prev && prev->s != DIFF_SYMBOL_PLUS &&
1008                             prev->s != DIFF_SYMBOL_MINUS)
1009                         prev = NULL;
1010                 if (next && next->s != DIFF_SYMBOL_PLUS &&
1011                             next->s != DIFF_SYMBOL_MINUS)
1012                         next = NULL;
1013
1014                 /* Inside a block? */
1015                 if ((prev &&
1016                     (prev->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK) ==
1017                     (l->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK)) &&
1018                     (next &&
1019                     (next->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK) ==
1020                     (l->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK))) {
1021                         l->flags |= DIFF_SYMBOL_MOVED_LINE_UNINTERESTING;
1022                         continue;
1023                 }
1024
1025                 /* Check if we are at an interesting bound: */
1026                 if (prev && (prev->flags & DIFF_SYMBOL_MOVED_LINE) &&
1027                     (prev->flags & DIFF_SYMBOL_MOVED_LINE_ALT) !=
1028                        (l->flags & DIFF_SYMBOL_MOVED_LINE_ALT))
1029                         continue;
1030                 if (next && (next->flags & DIFF_SYMBOL_MOVED_LINE) &&
1031                     (next->flags & DIFF_SYMBOL_MOVED_LINE_ALT) !=
1032                        (l->flags & DIFF_SYMBOL_MOVED_LINE_ALT))
1033                         continue;
1034
1035                 /*
1036                  * The boundary to prev and next are not interesting,
1037                  * so this line is not interesting as a whole
1038                  */
1039                 l->flags |= DIFF_SYMBOL_MOVED_LINE_UNINTERESTING;
1040         }
1041 }
1042
1043 static void emit_line_ws_markup(struct diff_options *o,
1044                                 const char *set, const char *reset,
1045                                 const char *line, int len, char sign,
1046                                 unsigned ws_rule, int blank_at_eof)
1047 {
1048         const char *ws = NULL;
1049
1050         if (o->ws_error_highlight & ws_rule) {
1051                 ws = diff_get_color_opt(o, DIFF_WHITESPACE);
1052                 if (!*ws)
1053                         ws = NULL;
1054         }
1055
1056         if (!ws)
1057                 emit_line_0(o, set, reset, sign, line, len);
1058         else if (blank_at_eof)
1059                 /* Blank line at EOF - paint '+' as well */
1060                 emit_line_0(o, ws, reset, sign, line, len);
1061         else {
1062                 /* Emit just the prefix, then the rest. */
1063                 emit_line_0(o, set, reset, sign, "", 0);
1064                 ws_check_emit(line, len, ws_rule,
1065                               o->file, set, reset, ws);
1066         }
1067 }
1068
1069 static void emit_diff_symbol_from_struct(struct diff_options *o,
1070                                          struct emitted_diff_symbol *eds)
1071 {
1072         static const char *nneof = " No newline at end of file\n";
1073         const char *context, *reset, *set, *meta, *fraginfo;
1074         struct strbuf sb = STRBUF_INIT;
1075
1076         enum diff_symbol s = eds->s;
1077         const char *line = eds->line;
1078         int len = eds->len;
1079         unsigned flags = eds->flags;
1080
1081         switch (s) {
1082         case DIFF_SYMBOL_NO_LF_EOF:
1083                 context = diff_get_color_opt(o, DIFF_CONTEXT);
1084                 reset = diff_get_color_opt(o, DIFF_RESET);
1085                 putc('\n', o->file);
1086                 emit_line_0(o, context, reset, '\\',
1087                             nneof, strlen(nneof));
1088                 break;
1089         case DIFF_SYMBOL_SUBMODULE_HEADER:
1090         case DIFF_SYMBOL_SUBMODULE_ERROR:
1091         case DIFF_SYMBOL_SUBMODULE_PIPETHROUGH:
1092         case DIFF_SYMBOL_STATS_SUMMARY_INSERTS_DELETES:
1093         case DIFF_SYMBOL_SUMMARY:
1094         case DIFF_SYMBOL_STATS_LINE:
1095         case DIFF_SYMBOL_BINARY_DIFF_BODY:
1096         case DIFF_SYMBOL_CONTEXT_FRAGINFO:
1097                 emit_line(o, "", "", line, len);
1098                 break;
1099         case DIFF_SYMBOL_CONTEXT_INCOMPLETE:
1100         case DIFF_SYMBOL_CONTEXT_MARKER:
1101                 context = diff_get_color_opt(o, DIFF_CONTEXT);
1102                 reset = diff_get_color_opt(o, DIFF_RESET);
1103                 emit_line(o, context, reset, line, len);
1104                 break;
1105         case DIFF_SYMBOL_SEPARATOR:
1106                 fprintf(o->file, "%s%c",
1107                         diff_line_prefix(o),
1108                         o->line_termination);
1109                 break;
1110         case DIFF_SYMBOL_CONTEXT:
1111                 set = diff_get_color_opt(o, DIFF_CONTEXT);
1112                 reset = diff_get_color_opt(o, DIFF_RESET);
1113                 emit_line_ws_markup(o, set, reset, line, len, ' ',
1114                                     flags & (DIFF_SYMBOL_CONTENT_WS_MASK), 0);
1115                 break;
1116         case DIFF_SYMBOL_PLUS:
1117                 switch (flags & (DIFF_SYMBOL_MOVED_LINE |
1118                                  DIFF_SYMBOL_MOVED_LINE_ALT |
1119                                  DIFF_SYMBOL_MOVED_LINE_UNINTERESTING)) {
1120                 case DIFF_SYMBOL_MOVED_LINE |
1121                      DIFF_SYMBOL_MOVED_LINE_ALT |
1122                      DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1123                         set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED_ALT_DIM);
1124                         break;
1125                 case DIFF_SYMBOL_MOVED_LINE |
1126                      DIFF_SYMBOL_MOVED_LINE_ALT:
1127                         set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED_ALT);
1128                         break;
1129                 case DIFF_SYMBOL_MOVED_LINE |
1130                      DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1131                         set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED_DIM);
1132                         break;
1133                 case DIFF_SYMBOL_MOVED_LINE:
1134                         set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED);
1135                         break;
1136                 default:
1137                         set = diff_get_color_opt(o, DIFF_FILE_NEW);
1138                 }
1139                 reset = diff_get_color_opt(o, DIFF_RESET);
1140                 emit_line_ws_markup(o, set, reset, line, len, '+',
1141                                     flags & DIFF_SYMBOL_CONTENT_WS_MASK,
1142                                     flags & DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF);
1143                 break;
1144         case DIFF_SYMBOL_MINUS:
1145                 switch (flags & (DIFF_SYMBOL_MOVED_LINE |
1146                                  DIFF_SYMBOL_MOVED_LINE_ALT |
1147                                  DIFF_SYMBOL_MOVED_LINE_UNINTERESTING)) {
1148                 case DIFF_SYMBOL_MOVED_LINE |
1149                      DIFF_SYMBOL_MOVED_LINE_ALT |
1150                      DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1151                         set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED_ALT_DIM);
1152                         break;
1153                 case DIFF_SYMBOL_MOVED_LINE |
1154                      DIFF_SYMBOL_MOVED_LINE_ALT:
1155                         set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED_ALT);
1156                         break;
1157                 case DIFF_SYMBOL_MOVED_LINE |
1158                      DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1159                         set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED_DIM);
1160                         break;
1161                 case DIFF_SYMBOL_MOVED_LINE:
1162                         set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED);
1163                         break;
1164                 default:
1165                         set = diff_get_color_opt(o, DIFF_FILE_OLD);
1166                 }
1167                 reset = diff_get_color_opt(o, DIFF_RESET);
1168                 emit_line_ws_markup(o, set, reset, line, len, '-',
1169                                     flags & DIFF_SYMBOL_CONTENT_WS_MASK, 0);
1170                 break;
1171         case DIFF_SYMBOL_WORDS_PORCELAIN:
1172                 context = diff_get_color_opt(o, DIFF_CONTEXT);
1173                 reset = diff_get_color_opt(o, DIFF_RESET);
1174                 emit_line(o, context, reset, line, len);
1175                 fputs("~\n", o->file);
1176                 break;
1177         case DIFF_SYMBOL_WORDS:
1178                 context = diff_get_color_opt(o, DIFF_CONTEXT);
1179                 reset = diff_get_color_opt(o, DIFF_RESET);
1180                 /*
1181                  * Skip the prefix character, if any.  With
1182                  * diff_suppress_blank_empty, there may be
1183                  * none.
1184                  */
1185                 if (line[0] != '\n') {
1186                         line++;
1187                         len--;
1188                 }
1189                 emit_line(o, context, reset, line, len);
1190                 break;
1191         case DIFF_SYMBOL_FILEPAIR_PLUS:
1192                 meta = diff_get_color_opt(o, DIFF_METAINFO);
1193                 reset = diff_get_color_opt(o, DIFF_RESET);
1194                 fprintf(o->file, "%s%s+++ %s%s%s\n", diff_line_prefix(o), meta,
1195                         line, reset,
1196                         strchr(line, ' ') ? "\t" : "");
1197                 break;
1198         case DIFF_SYMBOL_FILEPAIR_MINUS:
1199                 meta = diff_get_color_opt(o, DIFF_METAINFO);
1200                 reset = diff_get_color_opt(o, DIFF_RESET);
1201                 fprintf(o->file, "%s%s--- %s%s%s\n", diff_line_prefix(o), meta,
1202                         line, reset,
1203                         strchr(line, ' ') ? "\t" : "");
1204                 break;
1205         case DIFF_SYMBOL_BINARY_FILES:
1206         case DIFF_SYMBOL_HEADER:
1207                 fprintf(o->file, "%s", line);
1208                 break;
1209         case DIFF_SYMBOL_BINARY_DIFF_HEADER:
1210                 fprintf(o->file, "%sGIT binary patch\n", diff_line_prefix(o));
1211                 break;
1212         case DIFF_SYMBOL_BINARY_DIFF_HEADER_DELTA:
1213                 fprintf(o->file, "%sdelta %s\n", diff_line_prefix(o), line);
1214                 break;
1215         case DIFF_SYMBOL_BINARY_DIFF_HEADER_LITERAL:
1216                 fprintf(o->file, "%sliteral %s\n", diff_line_prefix(o), line);
1217                 break;
1218         case DIFF_SYMBOL_BINARY_DIFF_FOOTER:
1219                 fputs(diff_line_prefix(o), o->file);
1220                 fputc('\n', o->file);
1221                 break;
1222         case DIFF_SYMBOL_REWRITE_DIFF:
1223                 fraginfo = diff_get_color(o->use_color, DIFF_FRAGINFO);
1224                 reset = diff_get_color_opt(o, DIFF_RESET);
1225                 emit_line(o, fraginfo, reset, line, len);
1226                 break;
1227         case DIFF_SYMBOL_SUBMODULE_ADD:
1228                 set = diff_get_color_opt(o, DIFF_FILE_NEW);
1229                 reset = diff_get_color_opt(o, DIFF_RESET);
1230                 emit_line(o, set, reset, line, len);
1231                 break;
1232         case DIFF_SYMBOL_SUBMODULE_DEL:
1233                 set = diff_get_color_opt(o, DIFF_FILE_OLD);
1234                 reset = diff_get_color_opt(o, DIFF_RESET);
1235                 emit_line(o, set, reset, line, len);
1236                 break;
1237         case DIFF_SYMBOL_SUBMODULE_UNTRACKED:
1238                 fprintf(o->file, "%sSubmodule %s contains untracked content\n",
1239                         diff_line_prefix(o), line);
1240                 break;
1241         case DIFF_SYMBOL_SUBMODULE_MODIFIED:
1242                 fprintf(o->file, "%sSubmodule %s contains modified content\n",
1243                         diff_line_prefix(o), line);
1244                 break;
1245         case DIFF_SYMBOL_STATS_SUMMARY_NO_FILES:
1246                 emit_line(o, "", "", " 0 files changed\n",
1247                           strlen(" 0 files changed\n"));
1248                 break;
1249         case DIFF_SYMBOL_STATS_SUMMARY_ABBREV:
1250                 emit_line(o, "", "", " ...\n", strlen(" ...\n"));
1251                 break;
1252         case DIFF_SYMBOL_WORD_DIFF:
1253                 fprintf(o->file, "%.*s", len, line);
1254                 break;
1255         case DIFF_SYMBOL_STAT_SEP:
1256                 fputs(o->stat_sep, o->file);
1257                 break;
1258         default:
1259                 die("BUG: unknown diff symbol");
1260         }
1261         strbuf_release(&sb);
1262 }
1263
1264 static void emit_diff_symbol(struct diff_options *o, enum diff_symbol s,
1265                              const char *line, int len, unsigned flags)
1266 {
1267         struct emitted_diff_symbol e = {line, len, flags, s};
1268
1269         if (o->emitted_symbols)
1270                 append_emitted_diff_symbol(o, &e);
1271         else
1272                 emit_diff_symbol_from_struct(o, &e);
1273 }
1274
1275 void diff_emit_submodule_del(struct diff_options *o, const char *line)
1276 {
1277         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_DEL, line, strlen(line), 0);
1278 }
1279
1280 void diff_emit_submodule_add(struct diff_options *o, const char *line)
1281 {
1282         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_ADD, line, strlen(line), 0);
1283 }
1284
1285 void diff_emit_submodule_untracked(struct diff_options *o, const char *path)
1286 {
1287         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_UNTRACKED,
1288                          path, strlen(path), 0);
1289 }
1290
1291 void diff_emit_submodule_modified(struct diff_options *o, const char *path)
1292 {
1293         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_MODIFIED,
1294                          path, strlen(path), 0);
1295 }
1296
1297 void diff_emit_submodule_header(struct diff_options *o, const char *header)
1298 {
1299         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_HEADER,
1300                          header, strlen(header), 0);
1301 }
1302
1303 void diff_emit_submodule_error(struct diff_options *o, const char *err)
1304 {
1305         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_ERROR, err, strlen(err), 0);
1306 }
1307
1308 void diff_emit_submodule_pipethrough(struct diff_options *o,
1309                                      const char *line, int len)
1310 {
1311         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_PIPETHROUGH, line, len, 0);
1312 }
1313
1314 static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
1315 {
1316         if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
1317               ecbdata->blank_at_eof_in_preimage &&
1318               ecbdata->blank_at_eof_in_postimage &&
1319               ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
1320               ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
1321                 return 0;
1322         return ws_blank_line(line, len, ecbdata->ws_rule);
1323 }
1324
1325 static void emit_add_line(const char *reset,
1326                           struct emit_callback *ecbdata,
1327                           const char *line, int len)
1328 {
1329         unsigned flags = WSEH_NEW | ecbdata->ws_rule;
1330         if (new_blank_line_at_eof(ecbdata, line, len))
1331                 flags |= DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF;
1332
1333         emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_PLUS, line, len, flags);
1334 }
1335
1336 static void emit_del_line(const char *reset,
1337                           struct emit_callback *ecbdata,
1338                           const char *line, int len)
1339 {
1340         unsigned flags = WSEH_OLD | ecbdata->ws_rule;
1341         emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_MINUS, line, len, flags);
1342 }
1343
1344 static void emit_context_line(const char *reset,
1345                               struct emit_callback *ecbdata,
1346                               const char *line, int len)
1347 {
1348         unsigned flags = WSEH_CONTEXT | ecbdata->ws_rule;
1349         emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_CONTEXT, line, len, flags);
1350 }
1351
1352 static void emit_hunk_header(struct emit_callback *ecbdata,
1353                              const char *line, int len)
1354 {
1355         const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
1356         const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
1357         const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
1358         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1359         static const char atat[2] = { '@', '@' };
1360         const char *cp, *ep;
1361         struct strbuf msgbuf = STRBUF_INIT;
1362         int org_len = len;
1363         int i = 1;
1364
1365         /*
1366          * As a hunk header must begin with "@@ -<old>, +<new> @@",
1367          * it always is at least 10 bytes long.
1368          */
1369         if (len < 10 ||
1370             memcmp(line, atat, 2) ||
1371             !(ep = memmem(line + 2, len - 2, atat, 2))) {
1372                 emit_diff_symbol(ecbdata->opt,
1373                                  DIFF_SYMBOL_CONTEXT_MARKER, line, len, 0);
1374                 return;
1375         }
1376         ep += 2; /* skip over @@ */
1377
1378         /* The hunk header in fraginfo color */
1379         strbuf_addstr(&msgbuf, frag);
1380         strbuf_add(&msgbuf, line, ep - line);
1381         strbuf_addstr(&msgbuf, reset);
1382
1383         /*
1384          * trailing "\r\n"
1385          */
1386         for ( ; i < 3; i++)
1387                 if (line[len - i] == '\r' || line[len - i] == '\n')
1388                         len--;
1389
1390         /* blank before the func header */
1391         for (cp = ep; ep - line < len; ep++)
1392                 if (*ep != ' ' && *ep != '\t')
1393                         break;
1394         if (ep != cp) {
1395                 strbuf_addstr(&msgbuf, context);
1396                 strbuf_add(&msgbuf, cp, ep - cp);
1397                 strbuf_addstr(&msgbuf, reset);
1398         }
1399
1400         if (ep < line + len) {
1401                 strbuf_addstr(&msgbuf, func);
1402                 strbuf_add(&msgbuf, ep, line + len - ep);
1403                 strbuf_addstr(&msgbuf, reset);
1404         }
1405
1406         strbuf_add(&msgbuf, line + len, org_len - len);
1407         strbuf_complete_line(&msgbuf);
1408         emit_diff_symbol(ecbdata->opt,
1409                          DIFF_SYMBOL_CONTEXT_FRAGINFO, msgbuf.buf, msgbuf.len, 0);
1410         strbuf_release(&msgbuf);
1411 }
1412
1413 static struct diff_tempfile *claim_diff_tempfile(void) {
1414         int i;
1415         for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
1416                 if (!diff_temp[i].name)
1417                         return diff_temp + i;
1418         die("BUG: diff is failing to clean up its tempfiles");
1419 }
1420
1421 static void remove_tempfile(void)
1422 {
1423         int i;
1424         for (i = 0; i < ARRAY_SIZE(diff_temp); i++) {
1425                 if (is_tempfile_active(&diff_temp[i].tempfile))
1426                         delete_tempfile(&diff_temp[i].tempfile);
1427                 diff_temp[i].name = NULL;
1428         }
1429 }
1430
1431 static void add_line_count(struct strbuf *out, int count)
1432 {
1433         switch (count) {
1434         case 0:
1435                 strbuf_addstr(out, "0,0");
1436                 break;
1437         case 1:
1438                 strbuf_addstr(out, "1");
1439                 break;
1440         default:
1441                 strbuf_addf(out, "1,%d", count);
1442                 break;
1443         }
1444 }
1445
1446 static void emit_rewrite_lines(struct emit_callback *ecb,
1447                                int prefix, const char *data, int size)
1448 {
1449         const char *endp = NULL;
1450         const char *reset = diff_get_color(ecb->color_diff, DIFF_RESET);
1451
1452         while (0 < size) {
1453                 int len;
1454
1455                 endp = memchr(data, '\n', size);
1456                 len = endp ? (endp - data + 1) : size;
1457                 if (prefix != '+') {
1458                         ecb->lno_in_preimage++;
1459                         emit_del_line(reset, ecb, data, len);
1460                 } else {
1461                         ecb->lno_in_postimage++;
1462                         emit_add_line(reset, ecb, data, len);
1463                 }
1464                 size -= len;
1465                 data += len;
1466         }
1467         if (!endp)
1468                 emit_diff_symbol(ecb->opt, DIFF_SYMBOL_NO_LF_EOF, NULL, 0, 0);
1469 }
1470
1471 static void emit_rewrite_diff(const char *name_a,
1472                               const char *name_b,
1473                               struct diff_filespec *one,
1474                               struct diff_filespec *two,
1475                               struct userdiff_driver *textconv_one,
1476                               struct userdiff_driver *textconv_two,
1477                               struct diff_options *o)
1478 {
1479         int lc_a, lc_b;
1480         static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
1481         const char *a_prefix, *b_prefix;
1482         char *data_one, *data_two;
1483         size_t size_one, size_two;
1484         struct emit_callback ecbdata;
1485         struct strbuf out = STRBUF_INIT;
1486
1487         if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
1488                 a_prefix = o->b_prefix;
1489                 b_prefix = o->a_prefix;
1490         } else {
1491                 a_prefix = o->a_prefix;
1492                 b_prefix = o->b_prefix;
1493         }
1494
1495         name_a += (*name_a == '/');
1496         name_b += (*name_b == '/');
1497
1498         strbuf_reset(&a_name);
1499         strbuf_reset(&b_name);
1500         quote_two_c_style(&a_name, a_prefix, name_a, 0);
1501         quote_two_c_style(&b_name, b_prefix, name_b, 0);
1502
1503         size_one = fill_textconv(textconv_one, one, &data_one);
1504         size_two = fill_textconv(textconv_two, two, &data_two);
1505
1506         memset(&ecbdata, 0, sizeof(ecbdata));
1507         ecbdata.color_diff = want_color(o->use_color);
1508         ecbdata.ws_rule = whitespace_rule(name_b);
1509         ecbdata.opt = o;
1510         if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
1511                 mmfile_t mf1, mf2;
1512                 mf1.ptr = (char *)data_one;
1513                 mf2.ptr = (char *)data_two;
1514                 mf1.size = size_one;
1515                 mf2.size = size_two;
1516                 check_blank_at_eof(&mf1, &mf2, &ecbdata);
1517         }
1518         ecbdata.lno_in_preimage = 1;
1519         ecbdata.lno_in_postimage = 1;
1520
1521         lc_a = count_lines(data_one, size_one);
1522         lc_b = count_lines(data_two, size_two);
1523
1524         emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_MINUS,
1525                          a_name.buf, a_name.len, 0);
1526         emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_PLUS,
1527                          b_name.buf, b_name.len, 0);
1528
1529         strbuf_addstr(&out, "@@ -");
1530         if (!o->irreversible_delete)
1531                 add_line_count(&out, lc_a);
1532         else
1533                 strbuf_addstr(&out, "?,?");
1534         strbuf_addstr(&out, " +");
1535         add_line_count(&out, lc_b);
1536         strbuf_addstr(&out, " @@\n");
1537         emit_diff_symbol(o, DIFF_SYMBOL_REWRITE_DIFF, out.buf, out.len, 0);
1538         strbuf_release(&out);
1539
1540         if (lc_a && !o->irreversible_delete)
1541                 emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
1542         if (lc_b)
1543                 emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
1544         if (textconv_one)
1545                 free((char *)data_one);
1546         if (textconv_two)
1547                 free((char *)data_two);
1548 }
1549
1550 struct diff_words_buffer {
1551         mmfile_t text;
1552         long alloc;
1553         struct diff_words_orig {
1554                 const char *begin, *end;
1555         } *orig;
1556         int orig_nr, orig_alloc;
1557 };
1558
1559 static void diff_words_append(char *line, unsigned long len,
1560                 struct diff_words_buffer *buffer)
1561 {
1562         ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
1563         line++;
1564         len--;
1565         memcpy(buffer->text.ptr + buffer->text.size, line, len);
1566         buffer->text.size += len;
1567         buffer->text.ptr[buffer->text.size] = '\0';
1568 }
1569
1570 struct diff_words_style_elem {
1571         const char *prefix;
1572         const char *suffix;
1573         const char *color; /* NULL; filled in by the setup code if
1574                             * color is enabled */
1575 };
1576
1577 struct diff_words_style {
1578         enum diff_words_type type;
1579         struct diff_words_style_elem new, old, ctx;
1580         const char *newline;
1581 };
1582
1583 static struct diff_words_style diff_words_styles[] = {
1584         { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
1585         { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
1586         { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
1587 };
1588
1589 struct diff_words_data {
1590         struct diff_words_buffer minus, plus;
1591         const char *current_plus;
1592         int last_minus;
1593         struct diff_options *opt;
1594         regex_t *word_regex;
1595         enum diff_words_type type;
1596         struct diff_words_style *style;
1597 };
1598
1599 static int fn_out_diff_words_write_helper(struct diff_options *o,
1600                                           struct diff_words_style_elem *st_el,
1601                                           const char *newline,
1602                                           size_t count, const char *buf)
1603 {
1604         int print = 0;
1605         struct strbuf sb = STRBUF_INIT;
1606
1607         while (count) {
1608                 char *p = memchr(buf, '\n', count);
1609                 if (print)
1610                         strbuf_addstr(&sb, diff_line_prefix(o));
1611
1612                 if (p != buf) {
1613                         const char *reset = st_el->color && *st_el->color ?
1614                                             GIT_COLOR_RESET : NULL;
1615                         if (st_el->color && *st_el->color)
1616                                 strbuf_addstr(&sb, st_el->color);
1617                         strbuf_addstr(&sb, st_el->prefix);
1618                         strbuf_add(&sb, buf, p ? p - buf : count);
1619                         strbuf_addstr(&sb, st_el->suffix);
1620                         if (reset)
1621                                 strbuf_addstr(&sb, reset);
1622                 }
1623                 if (!p)
1624                         goto out;
1625
1626                 strbuf_addstr(&sb, newline);
1627                 count -= p + 1 - buf;
1628                 buf = p + 1;
1629                 print = 1;
1630                 if (count) {
1631                         emit_diff_symbol(o, DIFF_SYMBOL_WORD_DIFF,
1632                                          sb.buf, sb.len, 0);
1633                         strbuf_reset(&sb);
1634                 }
1635         }
1636
1637 out:
1638         if (sb.len)
1639                 emit_diff_symbol(o, DIFF_SYMBOL_WORD_DIFF,
1640                                  sb.buf, sb.len, 0);
1641         strbuf_release(&sb);
1642         return 0;
1643 }
1644
1645 /*
1646  * '--color-words' algorithm can be described as:
1647  *
1648  *   1. collect the minus/plus lines of a diff hunk, divided into
1649  *      minus-lines and plus-lines;
1650  *
1651  *   2. break both minus-lines and plus-lines into words and
1652  *      place them into two mmfile_t with one word for each line;
1653  *
1654  *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
1655  *
1656  * And for the common parts of the both file, we output the plus side text.
1657  * diff_words->current_plus is used to trace the current position of the plus file
1658  * which printed. diff_words->last_minus is used to trace the last minus word
1659  * printed.
1660  *
1661  * For '--graph' to work with '--color-words', we need to output the graph prefix
1662  * on each line of color words output. Generally, there are two conditions on
1663  * which we should output the prefix.
1664  *
1665  *   1. diff_words->last_minus == 0 &&
1666  *      diff_words->current_plus == diff_words->plus.text.ptr
1667  *
1668  *      that is: the plus text must start as a new line, and if there is no minus
1669  *      word printed, a graph prefix must be printed.
1670  *
1671  *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
1672  *      *(diff_words->current_plus - 1) == '\n'
1673  *
1674  *      that is: a graph prefix must be printed following a '\n'
1675  */
1676 static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
1677 {
1678         if ((diff_words->last_minus == 0 &&
1679                 diff_words->current_plus == diff_words->plus.text.ptr) ||
1680                 (diff_words->current_plus > diff_words->plus.text.ptr &&
1681                 *(diff_words->current_plus - 1) == '\n')) {
1682                 return 1;
1683         } else {
1684                 return 0;
1685         }
1686 }
1687
1688 static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
1689 {
1690         struct diff_words_data *diff_words = priv;
1691         struct diff_words_style *style = diff_words->style;
1692         int minus_first, minus_len, plus_first, plus_len;
1693         const char *minus_begin, *minus_end, *plus_begin, *plus_end;
1694         struct diff_options *opt = diff_words->opt;
1695         const char *line_prefix;
1696
1697         if (line[0] != '@' || parse_hunk_header(line, len,
1698                         &minus_first, &minus_len, &plus_first, &plus_len))
1699                 return;
1700
1701         assert(opt);
1702         line_prefix = diff_line_prefix(opt);
1703
1704         /* POSIX requires that first be decremented by one if len == 0... */
1705         if (minus_len) {
1706                 minus_begin = diff_words->minus.orig[minus_first].begin;
1707                 minus_end =
1708                         diff_words->minus.orig[minus_first + minus_len - 1].end;
1709         } else
1710                 minus_begin = minus_end =
1711                         diff_words->minus.orig[minus_first].end;
1712
1713         if (plus_len) {
1714                 plus_begin = diff_words->plus.orig[plus_first].begin;
1715                 plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
1716         } else
1717                 plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
1718
1719         if (color_words_output_graph_prefix(diff_words)) {
1720                 fputs(line_prefix, diff_words->opt->file);
1721         }
1722         if (diff_words->current_plus != plus_begin) {
1723                 fn_out_diff_words_write_helper(diff_words->opt,
1724                                 &style->ctx, style->newline,
1725                                 plus_begin - diff_words->current_plus,
1726                                 diff_words->current_plus);
1727         }
1728         if (minus_begin != minus_end) {
1729                 fn_out_diff_words_write_helper(diff_words->opt,
1730                                 &style->old, style->newline,
1731                                 minus_end - minus_begin, minus_begin);
1732         }
1733         if (plus_begin != plus_end) {
1734                 fn_out_diff_words_write_helper(diff_words->opt,
1735                                 &style->new, style->newline,
1736                                 plus_end - plus_begin, plus_begin);
1737         }
1738
1739         diff_words->current_plus = plus_end;
1740         diff_words->last_minus = minus_first;
1741 }
1742
1743 /* This function starts looking at *begin, and returns 0 iff a word was found. */
1744 static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
1745                 int *begin, int *end)
1746 {
1747         if (word_regex && *begin < buffer->size) {
1748                 regmatch_t match[1];
1749                 if (!regexec_buf(word_regex, buffer->ptr + *begin,
1750                                  buffer->size - *begin, 1, match, 0)) {
1751                         char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
1752                                         '\n', match[0].rm_eo - match[0].rm_so);
1753                         *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
1754                         *begin += match[0].rm_so;
1755                         return *begin >= *end;
1756                 }
1757                 return -1;
1758         }
1759
1760         /* find the next word */
1761         while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
1762                 (*begin)++;
1763         if (*begin >= buffer->size)
1764                 return -1;
1765
1766         /* find the end of the word */
1767         *end = *begin + 1;
1768         while (*end < buffer->size && !isspace(buffer->ptr[*end]))
1769                 (*end)++;
1770
1771         return 0;
1772 }
1773
1774 /*
1775  * This function splits the words in buffer->text, stores the list with
1776  * newline separator into out, and saves the offsets of the original words
1777  * in buffer->orig.
1778  */
1779 static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
1780                 regex_t *word_regex)
1781 {
1782         int i, j;
1783         long alloc = 0;
1784
1785         out->size = 0;
1786         out->ptr = NULL;
1787
1788         /* fake an empty "0th" word */
1789         ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
1790         buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
1791         buffer->orig_nr = 1;
1792
1793         for (i = 0; i < buffer->text.size; i++) {
1794                 if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
1795                         return;
1796
1797                 /* store original boundaries */
1798                 ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
1799                                 buffer->orig_alloc);
1800                 buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
1801                 buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
1802                 buffer->orig_nr++;
1803
1804                 /* store one word */
1805                 ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
1806                 memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
1807                 out->ptr[out->size + j - i] = '\n';
1808                 out->size += j - i + 1;
1809
1810                 i = j - 1;
1811         }
1812 }
1813
1814 /* this executes the word diff on the accumulated buffers */
1815 static void diff_words_show(struct diff_words_data *diff_words)
1816 {
1817         xpparam_t xpp;
1818         xdemitconf_t xecfg;
1819         mmfile_t minus, plus;
1820         struct diff_words_style *style = diff_words->style;
1821
1822         struct diff_options *opt = diff_words->opt;
1823         const char *line_prefix;
1824
1825         assert(opt);
1826         line_prefix = diff_line_prefix(opt);
1827
1828         /* special case: only removal */
1829         if (!diff_words->plus.text.size) {
1830                 emit_diff_symbol(diff_words->opt, DIFF_SYMBOL_WORD_DIFF,
1831                                  line_prefix, strlen(line_prefix), 0);
1832                 fn_out_diff_words_write_helper(diff_words->opt,
1833                         &style->old, style->newline,
1834                         diff_words->minus.text.size,
1835                         diff_words->minus.text.ptr);
1836                 diff_words->minus.text.size = 0;
1837                 return;
1838         }
1839
1840         diff_words->current_plus = diff_words->plus.text.ptr;
1841         diff_words->last_minus = 0;
1842
1843         memset(&xpp, 0, sizeof(xpp));
1844         memset(&xecfg, 0, sizeof(xecfg));
1845         diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
1846         diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
1847         xpp.flags = 0;
1848         /* as only the hunk header will be parsed, we need a 0-context */
1849         xecfg.ctxlen = 0;
1850         if (xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
1851                           &xpp, &xecfg))
1852                 die("unable to generate word diff");
1853         free(minus.ptr);
1854         free(plus.ptr);
1855         if (diff_words->current_plus != diff_words->plus.text.ptr +
1856                         diff_words->plus.text.size) {
1857                 if (color_words_output_graph_prefix(diff_words))
1858                         emit_diff_symbol(diff_words->opt, DIFF_SYMBOL_WORD_DIFF,
1859                                          line_prefix, strlen(line_prefix), 0);
1860                 fn_out_diff_words_write_helper(diff_words->opt,
1861                         &style->ctx, style->newline,
1862                         diff_words->plus.text.ptr + diff_words->plus.text.size
1863                         - diff_words->current_plus, diff_words->current_plus);
1864         }
1865         diff_words->minus.text.size = diff_words->plus.text.size = 0;
1866 }
1867
1868 /* In "color-words" mode, show word-diff of words accumulated in the buffer */
1869 static void diff_words_flush(struct emit_callback *ecbdata)
1870 {
1871         struct diff_options *wo = ecbdata->diff_words->opt;
1872
1873         if (ecbdata->diff_words->minus.text.size ||
1874             ecbdata->diff_words->plus.text.size)
1875                 diff_words_show(ecbdata->diff_words);
1876
1877         if (wo->emitted_symbols) {
1878                 struct diff_options *o = ecbdata->opt;
1879                 struct emitted_diff_symbols *wol = wo->emitted_symbols;
1880                 int i;
1881
1882                 /*
1883                  * NEEDSWORK:
1884                  * Instead of appending each, concat all words to a line?
1885                  */
1886                 for (i = 0; i < wol->nr; i++)
1887                         append_emitted_diff_symbol(o, &wol->buf[i]);
1888
1889                 for (i = 0; i < wol->nr; i++)
1890                         free((void *)wol->buf[i].line);
1891
1892                 wol->nr = 0;
1893         }
1894 }
1895
1896 static void diff_filespec_load_driver(struct diff_filespec *one)
1897 {
1898         /* Use already-loaded driver */
1899         if (one->driver)
1900                 return;
1901
1902         if (S_ISREG(one->mode))
1903                 one->driver = userdiff_find_by_path(one->path);
1904
1905         /* Fallback to default settings */
1906         if (!one->driver)
1907                 one->driver = userdiff_find_by_name("default");
1908 }
1909
1910 static const char *userdiff_word_regex(struct diff_filespec *one)
1911 {
1912         diff_filespec_load_driver(one);
1913         return one->driver->word_regex;
1914 }
1915
1916 static void init_diff_words_data(struct emit_callback *ecbdata,
1917                                  struct diff_options *orig_opts,
1918                                  struct diff_filespec *one,
1919                                  struct diff_filespec *two)
1920 {
1921         int i;
1922         struct diff_options *o = xmalloc(sizeof(struct diff_options));
1923         memcpy(o, orig_opts, sizeof(struct diff_options));
1924
1925         ecbdata->diff_words =
1926                 xcalloc(1, sizeof(struct diff_words_data));
1927         ecbdata->diff_words->type = o->word_diff;
1928         ecbdata->diff_words->opt = o;
1929
1930         if (orig_opts->emitted_symbols)
1931                 o->emitted_symbols =
1932                         xcalloc(1, sizeof(struct emitted_diff_symbols));
1933
1934         if (!o->word_regex)
1935                 o->word_regex = userdiff_word_regex(one);
1936         if (!o->word_regex)
1937                 o->word_regex = userdiff_word_regex(two);
1938         if (!o->word_regex)
1939                 o->word_regex = diff_word_regex_cfg;
1940         if (o->word_regex) {
1941                 ecbdata->diff_words->word_regex = (regex_t *)
1942                         xmalloc(sizeof(regex_t));
1943                 if (regcomp(ecbdata->diff_words->word_regex,
1944                             o->word_regex,
1945                             REG_EXTENDED | REG_NEWLINE))
1946                         die ("Invalid regular expression: %s",
1947                              o->word_regex);
1948         }
1949         for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
1950                 if (o->word_diff == diff_words_styles[i].type) {
1951                         ecbdata->diff_words->style =
1952                                 &diff_words_styles[i];
1953                         break;
1954                 }
1955         }
1956         if (want_color(o->use_color)) {
1957                 struct diff_words_style *st = ecbdata->diff_words->style;
1958                 st->old.color = diff_get_color_opt(o, DIFF_FILE_OLD);
1959                 st->new.color = diff_get_color_opt(o, DIFF_FILE_NEW);
1960                 st->ctx.color = diff_get_color_opt(o, DIFF_CONTEXT);
1961         }
1962 }
1963
1964 static void free_diff_words_data(struct emit_callback *ecbdata)
1965 {
1966         if (ecbdata->diff_words) {
1967                 diff_words_flush(ecbdata);
1968                 free (ecbdata->diff_words->opt->emitted_symbols);
1969                 free (ecbdata->diff_words->opt);
1970                 free (ecbdata->diff_words->minus.text.ptr);
1971                 free (ecbdata->diff_words->minus.orig);
1972                 free (ecbdata->diff_words->plus.text.ptr);
1973                 free (ecbdata->diff_words->plus.orig);
1974                 if (ecbdata->diff_words->word_regex) {
1975                         regfree(ecbdata->diff_words->word_regex);
1976                         free(ecbdata->diff_words->word_regex);
1977                 }
1978                 FREE_AND_NULL(ecbdata->diff_words);
1979         }
1980 }
1981
1982 const char *diff_get_color(int diff_use_color, enum color_diff ix)
1983 {
1984         if (want_color(diff_use_color))
1985                 return diff_colors[ix];
1986         return "";
1987 }
1988
1989 const char *diff_line_prefix(struct diff_options *opt)
1990 {
1991         struct strbuf *msgbuf;
1992         if (!opt->output_prefix)
1993                 return "";
1994
1995         msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
1996         return msgbuf->buf;
1997 }
1998
1999 static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
2000 {
2001         const char *cp;
2002         unsigned long allot;
2003         size_t l = len;
2004
2005         if (ecb->truncate)
2006                 return ecb->truncate(line, len);
2007         cp = line;
2008         allot = l;
2009         while (0 < l) {
2010                 (void) utf8_width(&cp, &l);
2011                 if (!cp)
2012                         break; /* truncated in the middle? */
2013         }
2014         return allot - l;
2015 }
2016
2017 static void find_lno(const char *line, struct emit_callback *ecbdata)
2018 {
2019         const char *p;
2020         ecbdata->lno_in_preimage = 0;
2021         ecbdata->lno_in_postimage = 0;
2022         p = strchr(line, '-');
2023         if (!p)
2024                 return; /* cannot happen */
2025         ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
2026         p = strchr(p, '+');
2027         if (!p)
2028                 return; /* cannot happen */
2029         ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
2030 }
2031
2032 static void fn_out_consume(void *priv, char *line, unsigned long len)
2033 {
2034         struct emit_callback *ecbdata = priv;
2035         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
2036         struct diff_options *o = ecbdata->opt;
2037
2038         o->found_changes = 1;
2039
2040         if (ecbdata->header) {
2041                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
2042                                  ecbdata->header->buf, ecbdata->header->len, 0);
2043                 strbuf_reset(ecbdata->header);
2044                 ecbdata->header = NULL;
2045         }
2046
2047         if (ecbdata->label_path[0]) {
2048                 emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_MINUS,
2049                                  ecbdata->label_path[0],
2050                                  strlen(ecbdata->label_path[0]), 0);
2051                 emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_PLUS,
2052                                  ecbdata->label_path[1],
2053                                  strlen(ecbdata->label_path[1]), 0);
2054                 ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
2055         }
2056
2057         if (diff_suppress_blank_empty
2058             && len == 2 && line[0] == ' ' && line[1] == '\n') {
2059                 line[0] = '\n';
2060                 len = 1;
2061         }
2062
2063         if (line[0] == '@') {
2064                 if (ecbdata->diff_words)
2065                         diff_words_flush(ecbdata);
2066                 len = sane_truncate_line(ecbdata, line, len);
2067                 find_lno(line, ecbdata);
2068                 emit_hunk_header(ecbdata, line, len);
2069                 return;
2070         }
2071
2072         if (ecbdata->diff_words) {
2073                 enum diff_symbol s =
2074                         ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN ?
2075                         DIFF_SYMBOL_WORDS_PORCELAIN : DIFF_SYMBOL_WORDS;
2076                 if (line[0] == '-') {
2077                         diff_words_append(line, len,
2078                                           &ecbdata->diff_words->minus);
2079                         return;
2080                 } else if (line[0] == '+') {
2081                         diff_words_append(line, len,
2082                                           &ecbdata->diff_words->plus);
2083                         return;
2084                 } else if (starts_with(line, "\\ ")) {
2085                         /*
2086                          * Eat the "no newline at eof" marker as if we
2087                          * saw a "+" or "-" line with nothing on it,
2088                          * and return without diff_words_flush() to
2089                          * defer processing. If this is the end of
2090                          * preimage, more "+" lines may come after it.
2091                          */
2092                         return;
2093                 }
2094                 diff_words_flush(ecbdata);
2095                 emit_diff_symbol(o, s, line, len, 0);
2096                 return;
2097         }
2098
2099         switch (line[0]) {
2100         case '+':
2101                 ecbdata->lno_in_postimage++;
2102                 emit_add_line(reset, ecbdata, line + 1, len - 1);
2103                 break;
2104         case '-':
2105                 ecbdata->lno_in_preimage++;
2106                 emit_del_line(reset, ecbdata, line + 1, len - 1);
2107                 break;
2108         case ' ':
2109                 ecbdata->lno_in_postimage++;
2110                 ecbdata->lno_in_preimage++;
2111                 emit_context_line(reset, ecbdata, line + 1, len - 1);
2112                 break;
2113         default:
2114                 /* incomplete line at the end */
2115                 ecbdata->lno_in_preimage++;
2116                 emit_diff_symbol(o, DIFF_SYMBOL_CONTEXT_INCOMPLETE,
2117                                  line, len, 0);
2118                 break;
2119         }
2120 }
2121
2122 static char *pprint_rename(const char *a, const char *b)
2123 {
2124         const char *old = a;
2125         const char *new = b;
2126         struct strbuf name = STRBUF_INIT;
2127         int pfx_length, sfx_length;
2128         int pfx_adjust_for_slash;
2129         int len_a = strlen(a);
2130         int len_b = strlen(b);
2131         int a_midlen, b_midlen;
2132         int qlen_a = quote_c_style(a, NULL, NULL, 0);
2133         int qlen_b = quote_c_style(b, NULL, NULL, 0);
2134
2135         if (qlen_a || qlen_b) {
2136                 quote_c_style(a, &name, NULL, 0);
2137                 strbuf_addstr(&name, " => ");
2138                 quote_c_style(b, &name, NULL, 0);
2139                 return strbuf_detach(&name, NULL);
2140         }
2141
2142         /* Find common prefix */
2143         pfx_length = 0;
2144         while (*old && *new && *old == *new) {
2145                 if (*old == '/')
2146                         pfx_length = old - a + 1;
2147                 old++;
2148                 new++;
2149         }
2150
2151         /* Find common suffix */
2152         old = a + len_a;
2153         new = b + len_b;
2154         sfx_length = 0;
2155         /*
2156          * If there is a common prefix, it must end in a slash.  In
2157          * that case we let this loop run 1 into the prefix to see the
2158          * same slash.
2159          *
2160          * If there is no common prefix, we cannot do this as it would
2161          * underrun the input strings.
2162          */
2163         pfx_adjust_for_slash = (pfx_length ? 1 : 0);
2164         while (a + pfx_length - pfx_adjust_for_slash <= old &&
2165                b + pfx_length - pfx_adjust_for_slash <= new &&
2166                *old == *new) {
2167                 if (*old == '/')
2168                         sfx_length = len_a - (old - a);
2169                 old--;
2170                 new--;
2171         }
2172
2173         /*
2174          * pfx{mid-a => mid-b}sfx
2175          * {pfx-a => pfx-b}sfx
2176          * pfx{sfx-a => sfx-b}
2177          * name-a => name-b
2178          */
2179         a_midlen = len_a - pfx_length - sfx_length;
2180         b_midlen = len_b - pfx_length - sfx_length;
2181         if (a_midlen < 0)
2182                 a_midlen = 0;
2183         if (b_midlen < 0)
2184                 b_midlen = 0;
2185
2186         strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
2187         if (pfx_length + sfx_length) {
2188                 strbuf_add(&name, a, pfx_length);
2189                 strbuf_addch(&name, '{');
2190         }
2191         strbuf_add(&name, a + pfx_length, a_midlen);
2192         strbuf_addstr(&name, " => ");
2193         strbuf_add(&name, b + pfx_length, b_midlen);
2194         if (pfx_length + sfx_length) {
2195                 strbuf_addch(&name, '}');
2196                 strbuf_add(&name, a + len_a - sfx_length, sfx_length);
2197         }
2198         return strbuf_detach(&name, NULL);
2199 }
2200
2201 struct diffstat_t {
2202         int nr;
2203         int alloc;
2204         struct diffstat_file {
2205                 char *from_name;
2206                 char *name;
2207                 char *print_name;
2208                 unsigned is_unmerged:1;
2209                 unsigned is_binary:1;
2210                 unsigned is_renamed:1;
2211                 unsigned is_interesting:1;
2212                 uintmax_t added, deleted;
2213         } **files;
2214 };
2215
2216 static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
2217                                           const char *name_a,
2218                                           const char *name_b)
2219 {
2220         struct diffstat_file *x;
2221         x = xcalloc(1, sizeof(*x));
2222         ALLOC_GROW(diffstat->files, diffstat->nr + 1, diffstat->alloc);
2223         diffstat->files[diffstat->nr++] = x;
2224         if (name_b) {
2225                 x->from_name = xstrdup(name_a);
2226                 x->name = xstrdup(name_b);
2227                 x->is_renamed = 1;
2228         }
2229         else {
2230                 x->from_name = NULL;
2231                 x->name = xstrdup(name_a);
2232         }
2233         return x;
2234 }
2235
2236 static void diffstat_consume(void *priv, char *line, unsigned long len)
2237 {
2238         struct diffstat_t *diffstat = priv;
2239         struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
2240
2241         if (line[0] == '+')
2242                 x->added++;
2243         else if (line[0] == '-')
2244                 x->deleted++;
2245 }
2246
2247 const char mime_boundary_leader[] = "------------";
2248
2249 static int scale_linear(int it, int width, int max_change)
2250 {
2251         if (!it)
2252                 return 0;
2253         /*
2254          * make sure that at least one '-' or '+' is printed if
2255          * there is any change to this path. The easiest way is to
2256          * scale linearly as if the alloted width is one column shorter
2257          * than it is, and then add 1 to the result.
2258          */
2259         return 1 + (it * (width - 1) / max_change);
2260 }
2261
2262 static void show_graph(struct strbuf *out, char ch, int cnt,
2263                        const char *set, const char *reset)
2264 {
2265         if (cnt <= 0)
2266                 return;
2267         strbuf_addstr(out, set);
2268         strbuf_addchars(out, ch, cnt);
2269         strbuf_addstr(out, reset);
2270 }
2271
2272 static void fill_print_name(struct diffstat_file *file)
2273 {
2274         char *pname;
2275
2276         if (file->print_name)
2277                 return;
2278
2279         if (!file->is_renamed) {
2280                 struct strbuf buf = STRBUF_INIT;
2281                 if (quote_c_style(file->name, &buf, NULL, 0)) {
2282                         pname = strbuf_detach(&buf, NULL);
2283                 } else {
2284                         pname = file->name;
2285                         strbuf_release(&buf);
2286                 }
2287         } else {
2288                 pname = pprint_rename(file->from_name, file->name);
2289         }
2290         file->print_name = pname;
2291 }
2292
2293 static void print_stat_summary_inserts_deletes(struct diff_options *options,
2294                 int files, int insertions, int deletions)
2295 {
2296         struct strbuf sb = STRBUF_INIT;
2297
2298         if (!files) {
2299                 assert(insertions == 0 && deletions == 0);
2300                 emit_diff_symbol(options, DIFF_SYMBOL_STATS_SUMMARY_NO_FILES,
2301                                  NULL, 0, 0);
2302                 return;
2303         }
2304
2305         strbuf_addf(&sb,
2306                     (files == 1) ? " %d file changed" : " %d files changed",
2307                     files);
2308
2309         /*
2310          * For binary diff, the caller may want to print "x files
2311          * changed" with insertions == 0 && deletions == 0.
2312          *
2313          * Not omitting "0 insertions(+), 0 deletions(-)" in this case
2314          * is probably less confusing (i.e skip over "2 files changed
2315          * but nothing about added/removed lines? Is this a bug in Git?").
2316          */
2317         if (insertions || deletions == 0) {
2318                 strbuf_addf(&sb,
2319                             (insertions == 1) ? ", %d insertion(+)" : ", %d insertions(+)",
2320                             insertions);
2321         }
2322
2323         if (deletions || insertions == 0) {
2324                 strbuf_addf(&sb,
2325                             (deletions == 1) ? ", %d deletion(-)" : ", %d deletions(-)",
2326                             deletions);
2327         }
2328         strbuf_addch(&sb, '\n');
2329         emit_diff_symbol(options, DIFF_SYMBOL_STATS_SUMMARY_INSERTS_DELETES,
2330                          sb.buf, sb.len, 0);
2331         strbuf_release(&sb);
2332 }
2333
2334 void print_stat_summary(FILE *fp, int files,
2335                         int insertions, int deletions)
2336 {
2337         struct diff_options o;
2338         memset(&o, 0, sizeof(o));
2339         o.file = fp;
2340
2341         print_stat_summary_inserts_deletes(&o, files, insertions, deletions);
2342 }
2343
2344 static void show_stats(struct diffstat_t *data, struct diff_options *options)
2345 {
2346         int i, len, add, del, adds = 0, dels = 0;
2347         uintmax_t max_change = 0, max_len = 0;
2348         int total_files = data->nr, count;
2349         int width, name_width, graph_width, number_width = 0, bin_width = 0;
2350         const char *reset, *add_c, *del_c;
2351         int extra_shown = 0;
2352         const char *line_prefix = diff_line_prefix(options);
2353         struct strbuf out = STRBUF_INIT;
2354
2355         if (data->nr == 0)
2356                 return;
2357
2358         count = options->stat_count ? options->stat_count : data->nr;
2359
2360         reset = diff_get_color_opt(options, DIFF_RESET);
2361         add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
2362         del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
2363
2364         /*
2365          * Find the longest filename and max number of changes
2366          */
2367         for (i = 0; (i < count) && (i < data->nr); i++) {
2368                 struct diffstat_file *file = data->files[i];
2369                 uintmax_t change = file->added + file->deleted;
2370
2371                 if (!file->is_interesting && (change == 0)) {
2372                         count++; /* not shown == room for one more */
2373                         continue;
2374                 }
2375                 fill_print_name(file);
2376                 len = strlen(file->print_name);
2377                 if (max_len < len)
2378                         max_len = len;
2379
2380                 if (file->is_unmerged) {
2381                         /* "Unmerged" is 8 characters */
2382                         bin_width = bin_width < 8 ? 8 : bin_width;
2383                         continue;
2384                 }
2385                 if (file->is_binary) {
2386                         /* "Bin XXX -> YYY bytes" */
2387                         int w = 14 + decimal_width(file->added)
2388                                 + decimal_width(file->deleted);
2389                         bin_width = bin_width < w ? w : bin_width;
2390                         /* Display change counts aligned with "Bin" */
2391                         number_width = 3;
2392                         continue;
2393                 }
2394
2395                 if (max_change < change)
2396                         max_change = change;
2397         }
2398         count = i; /* where we can stop scanning in data->files[] */
2399
2400         /*
2401          * We have width = stat_width or term_columns() columns total.
2402          * We want a maximum of min(max_len, stat_name_width) for the name part.
2403          * We want a maximum of min(max_change, stat_graph_width) for the +- part.
2404          * We also need 1 for " " and 4 + decimal_width(max_change)
2405          * for " | NNNN " and one the empty column at the end, altogether
2406          * 6 + decimal_width(max_change).
2407          *
2408          * If there's not enough space, we will use the smaller of
2409          * stat_name_width (if set) and 5/8*width for the filename,
2410          * and the rest for constant elements + graph part, but no more
2411          * than stat_graph_width for the graph part.
2412          * (5/8 gives 50 for filename and 30 for the constant parts + graph
2413          * for the standard terminal size).
2414          *
2415          * In other words: stat_width limits the maximum width, and
2416          * stat_name_width fixes the maximum width of the filename,
2417          * and is also used to divide available columns if there
2418          * aren't enough.
2419          *
2420          * Binary files are displayed with "Bin XXX -> YYY bytes"
2421          * instead of the change count and graph. This part is treated
2422          * similarly to the graph part, except that it is not
2423          * "scaled". If total width is too small to accommodate the
2424          * guaranteed minimum width of the filename part and the
2425          * separators and this message, this message will "overflow"
2426          * making the line longer than the maximum width.
2427          */
2428
2429         if (options->stat_width == -1)
2430                 width = term_columns() - strlen(line_prefix);
2431         else
2432                 width = options->stat_width ? options->stat_width : 80;
2433         number_width = decimal_width(max_change) > number_width ?
2434                 decimal_width(max_change) : number_width;
2435
2436         if (options->stat_graph_width == -1)
2437                 options->stat_graph_width = diff_stat_graph_width;
2438
2439         /*
2440          * Guarantee 3/8*16==6 for the graph part
2441          * and 5/8*16==10 for the filename part
2442          */
2443         if (width < 16 + 6 + number_width)
2444                 width = 16 + 6 + number_width;
2445
2446         /*
2447          * First assign sizes that are wanted, ignoring available width.
2448          * strlen("Bin XXX -> YYY bytes") == bin_width, and the part
2449          * starting from "XXX" should fit in graph_width.
2450          */
2451         graph_width = max_change + 4 > bin_width ? max_change : bin_width - 4;
2452         if (options->stat_graph_width &&
2453             options->stat_graph_width < graph_width)
2454                 graph_width = options->stat_graph_width;
2455
2456         name_width = (options->stat_name_width > 0 &&
2457                       options->stat_name_width < max_len) ?
2458                 options->stat_name_width : max_len;
2459
2460         /*
2461          * Adjust adjustable widths not to exceed maximum width
2462          */
2463         if (name_width + number_width + 6 + graph_width > width) {
2464                 if (graph_width > width * 3/8 - number_width - 6) {
2465                         graph_width = width * 3/8 - number_width - 6;
2466                         if (graph_width < 6)
2467                                 graph_width = 6;
2468                 }
2469
2470                 if (options->stat_graph_width &&
2471                     graph_width > options->stat_graph_width)
2472                         graph_width = options->stat_graph_width;
2473                 if (name_width > width - number_width - 6 - graph_width)
2474                         name_width = width - number_width - 6 - graph_width;
2475                 else
2476                         graph_width = width - number_width - 6 - name_width;
2477         }
2478
2479         /*
2480          * From here name_width is the width of the name area,
2481          * and graph_width is the width of the graph area.
2482          * max_change is used to scale graph properly.
2483          */
2484         for (i = 0; i < count; i++) {
2485                 const char *prefix = "";
2486                 struct diffstat_file *file = data->files[i];
2487                 char *name = file->print_name;
2488                 uintmax_t added = file->added;
2489                 uintmax_t deleted = file->deleted;
2490                 int name_len;
2491
2492                 if (!file->is_interesting && (added + deleted == 0))
2493                         continue;
2494
2495                 /*
2496                  * "scale" the filename
2497                  */
2498                 len = name_width;
2499                 name_len = strlen(name);
2500                 if (name_width < name_len) {
2501                         char *slash;
2502                         prefix = "...";
2503                         len -= 3;
2504                         name += name_len - len;
2505                         slash = strchr(name, '/');
2506                         if (slash)
2507                                 name = slash;
2508                 }
2509
2510                 if (file->is_binary) {
2511                         strbuf_addf(&out, " %s%-*s |", prefix, len, name);
2512                         strbuf_addf(&out, " %*s", number_width, "Bin");
2513                         if (!added && !deleted) {
2514                                 strbuf_addch(&out, '\n');
2515                                 emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2516                                                  out.buf, out.len, 0);
2517                                 strbuf_reset(&out);
2518                                 continue;
2519                         }
2520                         strbuf_addf(&out, " %s%"PRIuMAX"%s",
2521                                 del_c, deleted, reset);
2522                         strbuf_addstr(&out, " -> ");
2523                         strbuf_addf(&out, "%s%"PRIuMAX"%s",
2524                                 add_c, added, reset);
2525                         strbuf_addstr(&out, " bytes\n");
2526                         emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2527                                          out.buf, out.len, 0);
2528                         strbuf_reset(&out);
2529                         continue;
2530                 }
2531                 else if (file->is_unmerged) {
2532                         strbuf_addf(&out, " %s%-*s |", prefix, len, name);
2533                         strbuf_addstr(&out, " Unmerged\n");
2534                         emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2535                                          out.buf, out.len, 0);
2536                         strbuf_reset(&out);
2537                         continue;
2538                 }
2539
2540                 /*
2541                  * scale the add/delete
2542                  */
2543                 add = added;
2544                 del = deleted;
2545
2546                 if (graph_width <= max_change) {
2547                         int total = scale_linear(add + del, graph_width, max_change);
2548                         if (total < 2 && add && del)
2549                                 /* width >= 2 due to the sanity check */
2550                                 total = 2;
2551                         if (add < del) {
2552                                 add = scale_linear(add, graph_width, max_change);
2553                                 del = total - add;
2554                         } else {
2555                                 del = scale_linear(del, graph_width, max_change);
2556                                 add = total - del;
2557                         }
2558                 }
2559                 strbuf_addf(&out, " %s%-*s |", prefix, len, name);
2560                 strbuf_addf(&out, " %*"PRIuMAX"%s",
2561                         number_width, added + deleted,
2562                         added + deleted ? " " : "");
2563                 show_graph(&out, '+', add, add_c, reset);
2564                 show_graph(&out, '-', del, del_c, reset);
2565                 strbuf_addch(&out, '\n');
2566                 emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2567                                  out.buf, out.len, 0);
2568                 strbuf_reset(&out);
2569         }
2570
2571         for (i = 0; i < data->nr; i++) {
2572                 struct diffstat_file *file = data->files[i];
2573                 uintmax_t added = file->added;
2574                 uintmax_t deleted = file->deleted;
2575
2576                 if (file->is_unmerged ||
2577                     (!file->is_interesting && (added + deleted == 0))) {
2578                         total_files--;
2579                         continue;
2580                 }
2581
2582                 if (!file->is_binary) {
2583                         adds += added;
2584                         dels += deleted;
2585                 }
2586                 if (i < count)
2587                         continue;
2588                 if (!extra_shown)
2589                         emit_diff_symbol(options,
2590                                          DIFF_SYMBOL_STATS_SUMMARY_ABBREV,
2591                                          NULL, 0, 0);
2592                 extra_shown = 1;
2593         }
2594
2595         print_stat_summary_inserts_deletes(options, total_files, adds, dels);
2596 }
2597
2598 static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
2599 {
2600         int i, adds = 0, dels = 0, total_files = data->nr;
2601
2602         if (data->nr == 0)
2603                 return;
2604
2605         for (i = 0; i < data->nr; i++) {
2606                 int added = data->files[i]->added;
2607                 int deleted = data->files[i]->deleted;
2608
2609                 if (data->files[i]->is_unmerged ||
2610                     (!data->files[i]->is_interesting && (added + deleted == 0))) {
2611                         total_files--;
2612                 } else if (!data->files[i]->is_binary) { /* don't count bytes */
2613                         adds += added;
2614                         dels += deleted;
2615                 }
2616         }
2617         print_stat_summary_inserts_deletes(options, total_files, adds, dels);
2618 }
2619
2620 static void show_numstat(struct diffstat_t *data, struct diff_options *options)
2621 {
2622         int i;
2623
2624         if (data->nr == 0)
2625                 return;
2626
2627         for (i = 0; i < data->nr; i++) {
2628                 struct diffstat_file *file = data->files[i];
2629
2630                 fprintf(options->file, "%s", diff_line_prefix(options));
2631
2632                 if (file->is_binary)
2633                         fprintf(options->file, "-\t-\t");
2634                 else
2635                         fprintf(options->file,
2636                                 "%"PRIuMAX"\t%"PRIuMAX"\t",
2637                                 file->added, file->deleted);
2638                 if (options->line_termination) {
2639                         fill_print_name(file);
2640                         if (!file->is_renamed)
2641                                 write_name_quoted(file->name, options->file,
2642                                                   options->line_termination);
2643                         else {
2644                                 fputs(file->print_name, options->file);
2645                                 putc(options->line_termination, options->file);
2646                         }
2647                 } else {
2648                         if (file->is_renamed) {
2649                                 putc('\0', options->file);
2650                                 write_name_quoted(file->from_name, options->file, '\0');
2651                         }
2652                         write_name_quoted(file->name, options->file, '\0');
2653                 }
2654         }
2655 }
2656
2657 struct dirstat_file {
2658         const char *name;
2659         unsigned long changed;
2660 };
2661
2662 struct dirstat_dir {
2663         struct dirstat_file *files;
2664         int alloc, nr, permille, cumulative;
2665 };
2666
2667 static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
2668                 unsigned long changed, const char *base, int baselen)
2669 {
2670         unsigned long this_dir = 0;
2671         unsigned int sources = 0;
2672         const char *line_prefix = diff_line_prefix(opt);
2673
2674         while (dir->nr) {
2675                 struct dirstat_file *f = dir->files;
2676                 int namelen = strlen(f->name);
2677                 unsigned long this;
2678                 char *slash;
2679
2680                 if (namelen < baselen)
2681                         break;
2682                 if (memcmp(f->name, base, baselen))
2683                         break;
2684                 slash = strchr(f->name + baselen, '/');
2685                 if (slash) {
2686                         int newbaselen = slash + 1 - f->name;
2687                         this = gather_dirstat(opt, dir, changed, f->name, newbaselen);
2688                         sources++;
2689                 } else {
2690                         this = f->changed;
2691                         dir->files++;
2692                         dir->nr--;
2693                         sources += 2;
2694                 }
2695                 this_dir += this;
2696         }
2697
2698         /*
2699          * We don't report dirstat's for
2700          *  - the top level
2701          *  - or cases where everything came from a single directory
2702          *    under this directory (sources == 1).
2703          */
2704         if (baselen && sources != 1) {
2705                 if (this_dir) {
2706                         int permille = this_dir * 1000 / changed;
2707                         if (permille >= dir->permille) {
2708                                 fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
2709                                         permille / 10, permille % 10, baselen, base);
2710                                 if (!dir->cumulative)
2711                                         return 0;
2712                         }
2713                 }
2714         }
2715         return this_dir;
2716 }
2717
2718 static int dirstat_compare(const void *_a, const void *_b)
2719 {
2720         const struct dirstat_file *a = _a;
2721         const struct dirstat_file *b = _b;
2722         return strcmp(a->name, b->name);
2723 }
2724
2725 static void show_dirstat(struct diff_options *options)
2726 {
2727         int i;
2728         unsigned long changed;
2729         struct dirstat_dir dir;
2730         struct diff_queue_struct *q = &diff_queued_diff;
2731
2732         dir.files = NULL;
2733         dir.alloc = 0;
2734         dir.nr = 0;
2735         dir.permille = options->dirstat_permille;
2736         dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
2737
2738         changed = 0;
2739         for (i = 0; i < q->nr; i++) {
2740                 struct diff_filepair *p = q->queue[i];
2741                 const char *name;
2742                 unsigned long copied, added, damage;
2743                 int content_changed;
2744
2745                 name = p->two->path ? p->two->path : p->one->path;
2746
2747                 if (p->one->oid_valid && p->two->oid_valid)
2748                         content_changed = oidcmp(&p->one->oid, &p->two->oid);
2749                 else
2750                         content_changed = 1;
2751
2752                 if (!content_changed) {
2753                         /*
2754                          * The SHA1 has not changed, so pre-/post-content is
2755                          * identical. We can therefore skip looking at the
2756                          * file contents altogether.
2757                          */
2758                         damage = 0;
2759                         goto found_damage;
2760                 }
2761
2762                 if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE)) {
2763                         /*
2764                          * In --dirstat-by-file mode, we don't really need to
2765                          * look at the actual file contents at all.
2766                          * The fact that the SHA1 changed is enough for us to
2767                          * add this file to the list of results
2768                          * (with each file contributing equal damage).
2769                          */
2770                         damage = 1;
2771                         goto found_damage;
2772                 }
2773
2774                 if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
2775                         diff_populate_filespec(p->one, 0);
2776                         diff_populate_filespec(p->two, 0);
2777                         diffcore_count_changes(p->one, p->two, NULL, NULL,
2778                                                &copied, &added);
2779                         diff_free_filespec_data(p->one);
2780                         diff_free_filespec_data(p->two);
2781                 } else if (DIFF_FILE_VALID(p->one)) {
2782                         diff_populate_filespec(p->one, CHECK_SIZE_ONLY);
2783                         copied = added = 0;
2784                         diff_free_filespec_data(p->one);
2785                 } else if (DIFF_FILE_VALID(p->two)) {
2786                         diff_populate_filespec(p->two, CHECK_SIZE_ONLY);
2787                         copied = 0;
2788                         added = p->two->size;
2789                         diff_free_filespec_data(p->two);
2790                 } else
2791                         continue;
2792
2793                 /*
2794                  * Original minus copied is the removed material,
2795                  * added is the new material.  They are both damages
2796                  * made to the preimage.
2797                  * If the resulting damage is zero, we know that
2798                  * diffcore_count_changes() considers the two entries to
2799                  * be identical, but since content_changed is true, we
2800                  * know that there must have been _some_ kind of change,
2801                  * so we force all entries to have damage > 0.
2802                  */
2803                 damage = (p->one->size - copied) + added;
2804                 if (!damage)
2805                         damage = 1;
2806
2807 found_damage:
2808                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
2809                 dir.files[dir.nr].name = name;
2810                 dir.files[dir.nr].changed = damage;
2811                 changed += damage;
2812                 dir.nr++;
2813         }
2814
2815         /* This can happen even with many files, if everything was renames */
2816         if (!changed)
2817                 return;
2818
2819         /* Show all directories with more than x% of the changes */
2820         QSORT(dir.files, dir.nr, dirstat_compare);
2821         gather_dirstat(options, &dir, changed, "", 0);
2822 }
2823
2824 static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
2825 {
2826         int i;
2827         unsigned long changed;
2828         struct dirstat_dir dir;
2829
2830         if (data->nr == 0)
2831                 return;
2832
2833         dir.files = NULL;
2834         dir.alloc = 0;
2835         dir.nr = 0;
2836         dir.permille = options->dirstat_permille;
2837         dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
2838
2839         changed = 0;
2840         for (i = 0; i < data->nr; i++) {
2841                 struct diffstat_file *file = data->files[i];
2842                 unsigned long damage = file->added + file->deleted;
2843                 if (file->is_binary)
2844                         /*
2845                          * binary files counts bytes, not lines. Must find some
2846                          * way to normalize binary bytes vs. textual lines.
2847                          * The following heuristic assumes that there are 64
2848                          * bytes per "line".
2849                          * This is stupid and ugly, but very cheap...
2850                          */
2851                         damage = (damage + 63) / 64;
2852                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
2853                 dir.files[dir.nr].name = file->name;
2854                 dir.files[dir.nr].changed = damage;
2855                 changed += damage;
2856                 dir.nr++;
2857         }
2858
2859         /* This can happen even with many files, if everything was renames */
2860         if (!changed)
2861                 return;
2862
2863         /* Show all directories with more than x% of the changes */
2864         QSORT(dir.files, dir.nr, dirstat_compare);
2865         gather_dirstat(options, &dir, changed, "", 0);
2866 }
2867
2868 static void free_diffstat_info(struct diffstat_t *diffstat)
2869 {
2870         int i;
2871         for (i = 0; i < diffstat->nr; i++) {
2872                 struct diffstat_file *f = diffstat->files[i];
2873                 if (f->name != f->print_name)
2874                         free(f->print_name);
2875                 free(f->name);
2876                 free(f->from_name);
2877                 free(f);
2878         }
2879         free(diffstat->files);
2880 }
2881
2882 struct checkdiff_t {
2883         const char *filename;
2884         int lineno;
2885         int conflict_marker_size;
2886         struct diff_options *o;
2887         unsigned ws_rule;
2888         unsigned status;
2889 };
2890
2891 static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
2892 {
2893         char firstchar;
2894         int cnt;
2895
2896         if (len < marker_size + 1)
2897                 return 0;
2898         firstchar = line[0];
2899         switch (firstchar) {
2900         case '=': case '>': case '<': case '|':
2901                 break;
2902         default:
2903                 return 0;
2904         }
2905         for (cnt = 1; cnt < marker_size; cnt++)
2906                 if (line[cnt] != firstchar)
2907                         return 0;
2908         /* line[1] thru line[marker_size-1] are same as firstchar */
2909         if (len < marker_size + 1 || !isspace(line[marker_size]))
2910                 return 0;
2911         return 1;
2912 }
2913
2914 static void checkdiff_consume(void *priv, char *line, unsigned long len)
2915 {
2916         struct checkdiff_t *data = priv;
2917         int marker_size = data->conflict_marker_size;
2918         const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
2919         const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
2920         const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
2921         char *err;
2922         const char *line_prefix;
2923
2924         assert(data->o);
2925         line_prefix = diff_line_prefix(data->o);
2926
2927         if (line[0] == '+') {
2928                 unsigned bad;
2929                 data->lineno++;
2930                 if (is_conflict_marker(line + 1, marker_size, len - 1)) {
2931                         data->status |= 1;
2932                         fprintf(data->o->file,
2933                                 "%s%s:%d: leftover conflict marker\n",
2934                                 line_prefix, data->filename, data->lineno);
2935                 }
2936                 bad = ws_check(line + 1, len - 1, data->ws_rule);
2937                 if (!bad)
2938                         return;
2939                 data->status |= bad;
2940                 err = whitespace_error_string(bad);
2941                 fprintf(data->o->file, "%s%s:%d: %s.\n",
2942                         line_prefix, data->filename, data->lineno, err);
2943                 free(err);
2944                 emit_line(data->o, set, reset, line, 1);
2945                 ws_check_emit(line + 1, len - 1, data->ws_rule,
2946                               data->o->file, set, reset, ws);
2947         } else if (line[0] == ' ') {
2948                 data->lineno++;
2949         } else if (line[0] == '@') {
2950                 char *plus = strchr(line, '+');
2951                 if (plus)
2952                         data->lineno = strtol(plus, NULL, 10) - 1;
2953                 else
2954                         die("invalid diff");
2955         }
2956 }
2957
2958 static unsigned char *deflate_it(char *data,
2959                                  unsigned long size,
2960                                  unsigned long *result_size)
2961 {
2962         int bound;
2963         unsigned char *deflated;
2964         git_zstream stream;
2965
2966         git_deflate_init(&stream, zlib_compression_level);
2967         bound = git_deflate_bound(&stream, size);
2968         deflated = xmalloc(bound);
2969         stream.next_out = deflated;
2970         stream.avail_out = bound;
2971
2972         stream.next_in = (unsigned char *)data;
2973         stream.avail_in = size;
2974         while (git_deflate(&stream, Z_FINISH) == Z_OK)
2975                 ; /* nothing */
2976         git_deflate_end(&stream);
2977         *result_size = stream.total_out;
2978         return deflated;
2979 }
2980
2981 static void emit_binary_diff_body(struct diff_options *o,
2982                                   mmfile_t *one, mmfile_t *two)
2983 {
2984         void *cp;
2985         void *delta;
2986         void *deflated;
2987         void *data;
2988         unsigned long orig_size;
2989         unsigned long delta_size;
2990         unsigned long deflate_size;
2991         unsigned long data_size;
2992
2993         /* We could do deflated delta, or we could do just deflated two,
2994          * whichever is smaller.
2995          */
2996         delta = NULL;
2997         deflated = deflate_it(two->ptr, two->size, &deflate_size);
2998         if (one->size && two->size) {
2999                 delta = diff_delta(one->ptr, one->size,
3000                                    two->ptr, two->size,
3001                                    &delta_size, deflate_size);
3002                 if (delta) {
3003                         void *to_free = delta;
3004                         orig_size = delta_size;
3005                         delta = deflate_it(delta, delta_size, &delta_size);
3006                         free(to_free);
3007                 }
3008         }
3009
3010         if (delta && delta_size < deflate_size) {
3011                 char *s = xstrfmt("%lu", orig_size);
3012                 emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_HEADER_DELTA,
3013                                  s, strlen(s), 0);
3014                 free(s);
3015                 free(deflated);
3016                 data = delta;
3017                 data_size = delta_size;
3018         } else {
3019                 char *s = xstrfmt("%lu", two->size);
3020                 emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_HEADER_LITERAL,
3021                                  s, strlen(s), 0);
3022                 free(s);
3023                 free(delta);
3024                 data = deflated;
3025                 data_size = deflate_size;
3026         }
3027
3028         /* emit data encoded in base85 */
3029         cp = data;
3030         while (data_size) {
3031                 int len;
3032                 int bytes = (52 < data_size) ? 52 : data_size;
3033                 char line[71];
3034                 data_size -= bytes;
3035                 if (bytes <= 26)
3036                         line[0] = bytes + 'A' - 1;
3037                 else
3038                         line[0] = bytes - 26 + 'a' - 1;
3039                 encode_85(line + 1, cp, bytes);
3040                 cp = (char *) cp + bytes;
3041
3042                 len = strlen(line);
3043                 line[len++] = '\n';
3044                 line[len] = '\0';
3045
3046                 emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_BODY,
3047                                  line, len, 0);
3048         }
3049         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_FOOTER, NULL, 0, 0);
3050         free(data);
3051 }
3052
3053 static void emit_binary_diff(struct diff_options *o,
3054                              mmfile_t *one, mmfile_t *two)
3055 {
3056         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_HEADER, NULL, 0, 0);
3057         emit_binary_diff_body(o, one, two);
3058         emit_binary_diff_body(o, two, one);
3059 }
3060
3061 int diff_filespec_is_binary(struct diff_filespec *one)
3062 {
3063         if (one->is_binary == -1) {
3064                 diff_filespec_load_driver(one);
3065                 if (one->driver->binary != -1)
3066                         one->is_binary = one->driver->binary;
3067                 else {
3068                         if (!one->data && DIFF_FILE_VALID(one))
3069                                 diff_populate_filespec(one, CHECK_BINARY);
3070                         if (one->is_binary == -1 && one->data)
3071                                 one->is_binary = buffer_is_binary(one->data,
3072                                                 one->size);
3073                         if (one->is_binary == -1)
3074                                 one->is_binary = 0;
3075                 }
3076         }
3077         return one->is_binary;
3078 }
3079
3080 static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
3081 {
3082         diff_filespec_load_driver(one);
3083         return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
3084 }
3085
3086 void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
3087 {
3088         if (!options->a_prefix)
3089                 options->a_prefix = a;
3090         if (!options->b_prefix)
3091                 options->b_prefix = b;
3092 }
3093
3094 struct userdiff_driver *get_textconv(struct diff_filespec *one)
3095 {
3096         if (!DIFF_FILE_VALID(one))
3097                 return NULL;
3098
3099         diff_filespec_load_driver(one);
3100         return userdiff_get_textconv(one->driver);
3101 }
3102
3103 static void builtin_diff(const char *name_a,
3104                          const char *name_b,
3105                          struct diff_filespec *one,
3106                          struct diff_filespec *two,
3107                          const char *xfrm_msg,
3108                          int must_show_header,
3109                          struct diff_options *o,
3110                          int complete_rewrite)
3111 {
3112         mmfile_t mf1, mf2;
3113         const char *lbl[2];
3114         char *a_one, *b_two;
3115         const char *meta = diff_get_color_opt(o, DIFF_METAINFO);
3116         const char *reset = diff_get_color_opt(o, DIFF_RESET);
3117         const char *a_prefix, *b_prefix;
3118         struct userdiff_driver *textconv_one = NULL;
3119         struct userdiff_driver *textconv_two = NULL;
3120         struct strbuf header = STRBUF_INIT;
3121         const char *line_prefix = diff_line_prefix(o);
3122
3123         diff_set_mnemonic_prefix(o, "a/", "b/");
3124         if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
3125                 a_prefix = o->b_prefix;
3126                 b_prefix = o->a_prefix;
3127         } else {
3128                 a_prefix = o->a_prefix;
3129                 b_prefix = o->b_prefix;
3130         }
3131
3132         if (o->submodule_format == DIFF_SUBMODULE_LOG &&
3133             (!one->mode || S_ISGITLINK(one->mode)) &&
3134             (!two->mode || S_ISGITLINK(two->mode))) {
3135                 show_submodule_summary(o, one->path ? one->path : two->path,
3136                                 &one->oid, &two->oid,
3137                                 two->dirty_submodule);
3138                 return;
3139         } else if (o->submodule_format == DIFF_SUBMODULE_INLINE_DIFF &&
3140                    (!one->mode || S_ISGITLINK(one->mode)) &&
3141                    (!two->mode || S_ISGITLINK(two->mode))) {
3142                 show_submodule_inline_diff(o, one->path ? one->path : two->path,
3143                                 &one->oid, &two->oid,
3144                                 two->dirty_submodule);
3145                 return;
3146         }
3147
3148         if (DIFF_OPT_TST(o, ALLOW_TEXTCONV)) {
3149                 textconv_one = get_textconv(one);
3150                 textconv_two = get_textconv(two);
3151         }
3152
3153         /* Never use a non-valid filename anywhere if at all possible */
3154         name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
3155         name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
3156
3157         a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
3158         b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
3159         lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
3160         lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
3161         strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, meta, a_one, b_two, reset);
3162         if (lbl[0][0] == '/') {
3163                 /* /dev/null */
3164                 strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, meta, two->mode, reset);
3165                 if (xfrm_msg)
3166                         strbuf_addstr(&header, xfrm_msg);
3167                 must_show_header = 1;
3168         }
3169         else if (lbl[1][0] == '/') {
3170                 strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, meta, one->mode, reset);
3171                 if (xfrm_msg)
3172                         strbuf_addstr(&header, xfrm_msg);
3173                 must_show_header = 1;
3174         }
3175         else {
3176                 if (one->mode != two->mode) {
3177                         strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, meta, one->mode, reset);
3178                         strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, meta, two->mode, reset);
3179                         must_show_header = 1;
3180                 }
3181                 if (xfrm_msg)
3182                         strbuf_addstr(&header, xfrm_msg);
3183
3184                 /*
3185                  * we do not run diff between different kind
3186                  * of objects.
3187                  */
3188                 if ((one->mode ^ two->mode) & S_IFMT)
3189                         goto free_ab_and_return;
3190                 if (complete_rewrite &&
3191                     (textconv_one || !diff_filespec_is_binary(one)) &&
3192                     (textconv_two || !diff_filespec_is_binary(two))) {
3193                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3194                                          header.buf, header.len, 0);
3195                         strbuf_reset(&header);
3196                         emit_rewrite_diff(name_a, name_b, one, two,
3197                                                 textconv_one, textconv_two, o);
3198                         o->found_changes = 1;
3199                         goto free_ab_and_return;
3200                 }
3201         }
3202
3203         if (o->irreversible_delete && lbl[1][0] == '/') {
3204                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER, header.buf,
3205                                  header.len, 0);
3206                 strbuf_reset(&header);
3207                 goto free_ab_and_return;
3208         } else if (!DIFF_OPT_TST(o, TEXT) &&
3209             ( (!textconv_one && diff_filespec_is_binary(one)) ||
3210               (!textconv_two && diff_filespec_is_binary(two)) )) {
3211                 struct strbuf sb = STRBUF_INIT;
3212                 if (!one->data && !two->data &&
3213                     S_ISREG(one->mode) && S_ISREG(two->mode) &&
3214                     !DIFF_OPT_TST(o, BINARY)) {
3215                         if (!oidcmp(&one->oid, &two->oid)) {
3216                                 if (must_show_header)
3217                                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3218                                                          header.buf, header.len,
3219                                                          0);
3220                                 goto free_ab_and_return;
3221                         }
3222                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3223                                          header.buf, header.len, 0);
3224                         strbuf_addf(&sb, "%sBinary files %s and %s differ\n",
3225                                     diff_line_prefix(o), lbl[0], lbl[1]);
3226                         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_FILES,
3227                                          sb.buf, sb.len, 0);
3228                         strbuf_release(&sb);
3229                         goto free_ab_and_return;
3230                 }
3231                 if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
3232                         die("unable to read files to diff");
3233                 /* Quite common confusing case */
3234                 if (mf1.size == mf2.size &&
3235                     !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
3236                         if (must_show_header)
3237                                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3238                                                  header.buf, header.len, 0);
3239                         goto free_ab_and_return;
3240                 }
3241                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER, header.buf, header.len, 0);
3242                 strbuf_reset(&header);
3243                 if (DIFF_OPT_TST(o, BINARY))
3244                         emit_binary_diff(o, &mf1, &mf2);
3245                 else {
3246                         strbuf_addf(&sb, "%sBinary files %s and %s differ\n",
3247                                     diff_line_prefix(o), lbl[0], lbl[1]);
3248                         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_FILES,
3249                                          sb.buf, sb.len, 0);
3250                         strbuf_release(&sb);
3251                 }
3252                 o->found_changes = 1;
3253         } else {
3254                 /* Crazy xdl interfaces.. */
3255                 const char *diffopts = getenv("GIT_DIFF_OPTS");
3256                 const char *v;
3257                 xpparam_t xpp;
3258                 xdemitconf_t xecfg;
3259                 struct emit_callback ecbdata;
3260                 const struct userdiff_funcname *pe;
3261
3262                 if (must_show_header) {
3263                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3264                                          header.buf, header.len, 0);
3265                         strbuf_reset(&header);
3266                 }
3267
3268                 mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
3269                 mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
3270
3271                 pe = diff_funcname_pattern(one);
3272                 if (!pe)
3273                         pe = diff_funcname_pattern(two);
3274
3275                 memset(&xpp, 0, sizeof(xpp));
3276                 memset(&xecfg, 0, sizeof(xecfg));
3277                 memset(&ecbdata, 0, sizeof(ecbdata));
3278                 ecbdata.label_path = lbl;
3279                 ecbdata.color_diff = want_color(o->use_color);
3280                 ecbdata.ws_rule = whitespace_rule(name_b);
3281                 if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
3282                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
3283                 ecbdata.opt = o;
3284                 ecbdata.header = header.len ? &header : NULL;
3285                 xpp.flags = o->xdl_opts;
3286                 xecfg.ctxlen = o->context;
3287                 xecfg.interhunkctxlen = o->interhunkcontext;
3288                 xecfg.flags = XDL_EMIT_FUNCNAMES;
3289                 if (DIFF_OPT_TST(o, FUNCCONTEXT))
3290                         xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
3291                 if (pe)
3292                         xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
3293                 if (!diffopts)
3294                         ;
3295                 else if (skip_prefix(diffopts, "--unified=", &v))
3296                         xecfg.ctxlen = strtoul(v, NULL, 10);
3297                 else if (skip_prefix(diffopts, "-u", &v))
3298                         xecfg.ctxlen = strtoul(v, NULL, 10);
3299                 if (o->word_diff)
3300                         init_diff_words_data(&ecbdata, o, one, two);
3301                 if (xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
3302                                   &xpp, &xecfg))
3303                         die("unable to generate diff for %s", one->path);
3304                 if (o->word_diff)
3305                         free_diff_words_data(&ecbdata);
3306                 if (textconv_one)
3307                         free(mf1.ptr);
3308                 if (textconv_two)
3309                         free(mf2.ptr);
3310                 xdiff_clear_find_func(&xecfg);
3311         }
3312
3313  free_ab_and_return:
3314         strbuf_release(&header);
3315         diff_free_filespec_data(one);
3316         diff_free_filespec_data(two);
3317         free(a_one);
3318         free(b_two);
3319         return;
3320 }
3321
3322 static void builtin_diffstat(const char *name_a, const char *name_b,
3323                              struct diff_filespec *one,
3324                              struct diff_filespec *two,
3325                              struct diffstat_t *diffstat,
3326                              struct diff_options *o,
3327                              struct diff_filepair *p)
3328 {
3329         mmfile_t mf1, mf2;
3330         struct diffstat_file *data;
3331         int same_contents;
3332         int complete_rewrite = 0;
3333
3334         if (!DIFF_PAIR_UNMERGED(p)) {
3335                 if (p->status == DIFF_STATUS_MODIFIED && p->score)
3336                         complete_rewrite = 1;
3337         }
3338
3339         data = diffstat_add(diffstat, name_a, name_b);
3340         data->is_interesting = p->status != DIFF_STATUS_UNKNOWN;
3341
3342         if (!one || !two) {
3343                 data->is_unmerged = 1;
3344                 return;
3345         }
3346
3347         same_contents = !oidcmp(&one->oid, &two->oid);
3348
3349         if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
3350                 data->is_binary = 1;
3351                 if (same_contents) {
3352                         data->added = 0;
3353                         data->deleted = 0;
3354                 } else {
3355                         data->added = diff_filespec_size(two);
3356                         data->deleted = diff_filespec_size(one);
3357                 }
3358         }
3359
3360         else if (complete_rewrite) {
3361                 diff_populate_filespec(one, 0);
3362                 diff_populate_filespec(two, 0);
3363                 data->deleted = count_lines(one->data, one->size);
3364                 data->added = count_lines(two->data, two->size);
3365         }
3366
3367         else if (!same_contents) {
3368                 /* Crazy xdl interfaces.. */
3369                 xpparam_t xpp;
3370                 xdemitconf_t xecfg;
3371
3372                 if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
3373                         die("unable to read files to diff");
3374
3375                 memset(&xpp, 0, sizeof(xpp));
3376                 memset(&xecfg, 0, sizeof(xecfg));
3377                 xpp.flags = o->xdl_opts;
3378                 xecfg.ctxlen = o->context;
3379                 xecfg.interhunkctxlen = o->interhunkcontext;
3380                 if (xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
3381                                   &xpp, &xecfg))
3382                         die("unable to generate diffstat for %s", one->path);
3383         }
3384
3385         diff_free_filespec_data(one);
3386         diff_free_filespec_data(two);
3387 }
3388
3389 static void builtin_checkdiff(const char *name_a, const char *name_b,
3390                               const char *attr_path,
3391                               struct diff_filespec *one,
3392                               struct diff_filespec *two,
3393                               struct diff_options *o)
3394 {
3395         mmfile_t mf1, mf2;
3396         struct checkdiff_t data;
3397
3398         if (!two)
3399                 return;
3400
3401         memset(&data, 0, sizeof(data));
3402         data.filename = name_b ? name_b : name_a;
3403         data.lineno = 0;
3404         data.o = o;
3405         data.ws_rule = whitespace_rule(attr_path);
3406         data.conflict_marker_size = ll_merge_marker_size(attr_path);
3407
3408         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
3409                 die("unable to read files to diff");
3410
3411         /*
3412          * All the other codepaths check both sides, but not checking
3413          * the "old" side here is deliberate.  We are checking the newly
3414          * introduced changes, and as long as the "new" side is text, we
3415          * can and should check what it introduces.
3416          */
3417         if (diff_filespec_is_binary(two))
3418                 goto free_and_return;
3419         else {
3420                 /* Crazy xdl interfaces.. */
3421                 xpparam_t xpp;
3422                 xdemitconf_t xecfg;
3423
3424                 memset(&xpp, 0, sizeof(xpp));
3425                 memset(&xecfg, 0, sizeof(xecfg));
3426                 xecfg.ctxlen = 1; /* at least one context line */
3427                 xpp.flags = 0;
3428                 if (xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
3429                                   &xpp, &xecfg))
3430                         die("unable to generate checkdiff for %s", one->path);
3431
3432                 if (data.ws_rule & WS_BLANK_AT_EOF) {
3433                         struct emit_callback ecbdata;
3434                         int blank_at_eof;
3435
3436                         ecbdata.ws_rule = data.ws_rule;
3437                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
3438                         blank_at_eof = ecbdata.blank_at_eof_in_postimage;
3439
3440                         if (blank_at_eof) {
3441                                 static char *err;
3442                                 if (!err)
3443                                         err = whitespace_error_string(WS_BLANK_AT_EOF);
3444                                 fprintf(o->file, "%s:%d: %s.\n",
3445                                         data.filename, blank_at_eof, err);
3446                                 data.status = 1; /* report errors */
3447                         }
3448                 }
3449         }
3450  free_and_return:
3451         diff_free_filespec_data(one);
3452         diff_free_filespec_data(two);
3453         if (data.status)
3454                 DIFF_OPT_SET(o, CHECK_FAILED);
3455 }
3456
3457 struct diff_filespec *alloc_filespec(const char *path)
3458 {
3459         struct diff_filespec *spec;
3460
3461         FLEXPTR_ALLOC_STR(spec, path, path);
3462         spec->count = 1;
3463         spec->is_binary = -1;
3464         return spec;
3465 }
3466
3467 void free_filespec(struct diff_filespec *spec)
3468 {
3469         if (!--spec->count) {
3470                 diff_free_filespec_data(spec);
3471                 free(spec);
3472         }
3473 }
3474
3475 void fill_filespec(struct diff_filespec *spec, const struct object_id *oid,
3476                    int oid_valid, unsigned short mode)
3477 {
3478         if (mode) {
3479                 spec->mode = canon_mode(mode);
3480                 oidcpy(&spec->oid, oid);
3481                 spec->oid_valid = oid_valid;
3482         }
3483 }
3484
3485 /*
3486  * Given a name and sha1 pair, if the index tells us the file in
3487  * the work tree has that object contents, return true, so that
3488  * prepare_temp_file() does not have to inflate and extract.
3489  */
3490 static int reuse_worktree_file(const char *name, const struct object_id *oid, int want_file)
3491 {
3492         const struct cache_entry *ce;
3493         struct stat st;
3494         int pos, len;
3495
3496         /*
3497          * We do not read the cache ourselves here, because the
3498          * benchmark with my previous version that always reads cache
3499          * shows that it makes things worse for diff-tree comparing
3500          * two linux-2.6 kernel trees in an already checked out work
3501          * tree.  This is because most diff-tree comparisons deal with
3502          * only a small number of files, while reading the cache is
3503          * expensive for a large project, and its cost outweighs the
3504          * savings we get by not inflating the object to a temporary
3505          * file.  Practically, this code only helps when we are used
3506          * by diff-cache --cached, which does read the cache before
3507          * calling us.
3508          */
3509         if (!active_cache)
3510                 return 0;
3511
3512         /* We want to avoid the working directory if our caller
3513          * doesn't need the data in a normal file, this system
3514          * is rather slow with its stat/open/mmap/close syscalls,
3515          * and the object is contained in a pack file.  The pack
3516          * is probably already open and will be faster to obtain
3517          * the data through than the working directory.  Loose
3518          * objects however would tend to be slower as they need
3519          * to be individually opened and inflated.
3520          */
3521         if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(oid->hash))
3522                 return 0;
3523
3524         /*
3525          * Similarly, if we'd have to convert the file contents anyway, that
3526          * makes the optimization not worthwhile.
3527          */
3528         if (!want_file && would_convert_to_git(&the_index, name))
3529                 return 0;
3530
3531         len = strlen(name);
3532         pos = cache_name_pos(name, len);
3533         if (pos < 0)
3534                 return 0;
3535         ce = active_cache[pos];
3536
3537         /*
3538          * This is not the sha1 we are looking for, or
3539          * unreusable because it is not a regular file.
3540          */
3541         if (oidcmp(oid, &ce->oid) || !S_ISREG(ce->ce_mode))
3542                 return 0;
3543
3544         /*
3545          * If ce is marked as "assume unchanged", there is no
3546          * guarantee that work tree matches what we are looking for.
3547          */
3548         if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
3549                 return 0;
3550
3551         /*
3552          * If ce matches the file in the work tree, we can reuse it.
3553          */
3554         if (ce_uptodate(ce) ||
3555             (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
3556                 return 1;
3557
3558         return 0;
3559 }
3560
3561 static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
3562 {
3563         struct strbuf buf = STRBUF_INIT;
3564         char *dirty = "";
3565
3566         /* Are we looking at the work tree? */
3567         if (s->dirty_submodule)
3568                 dirty = "-dirty";
3569
3570         strbuf_addf(&buf, "Subproject commit %s%s\n",
3571                     oid_to_hex(&s->oid), dirty);
3572         s->size = buf.len;
3573         if (size_only) {
3574                 s->data = NULL;
3575                 strbuf_release(&buf);
3576         } else {
3577                 s->data = strbuf_detach(&buf, NULL);
3578                 s->should_free = 1;
3579         }
3580         return 0;
3581 }
3582
3583 /*
3584  * While doing rename detection and pickaxe operation, we may need to
3585  * grab the data for the blob (or file) for our own in-core comparison.
3586  * diff_filespec has data and size fields for this purpose.
3587  */
3588 int diff_populate_filespec(struct diff_filespec *s, unsigned int flags)
3589 {
3590         int size_only = flags & CHECK_SIZE_ONLY;
3591         int err = 0;
3592         /*
3593          * demote FAIL to WARN to allow inspecting the situation
3594          * instead of refusing.
3595          */
3596         enum safe_crlf crlf_warn = (safe_crlf == SAFE_CRLF_FAIL
3597                                     ? SAFE_CRLF_WARN
3598                                     : safe_crlf);
3599
3600         if (!DIFF_FILE_VALID(s))
3601                 die("internal error: asking to populate invalid file.");
3602         if (S_ISDIR(s->mode))
3603                 return -1;
3604
3605         if (s->data)
3606                 return 0;
3607
3608         if (size_only && 0 < s->size)
3609                 return 0;
3610
3611         if (S_ISGITLINK(s->mode))
3612                 return diff_populate_gitlink(s, size_only);
3613
3614         if (!s->oid_valid ||
3615             reuse_worktree_file(s->path, &s->oid, 0)) {
3616                 struct strbuf buf = STRBUF_INIT;
3617                 struct stat st;
3618                 int fd;
3619
3620                 if (lstat(s->path, &st) < 0) {
3621                         if (errno == ENOENT) {
3622                         err_empty:
3623                                 err = -1;
3624                         empty:
3625                                 s->data = (char *)"";
3626                                 s->size = 0;
3627                                 return err;
3628                         }
3629                 }
3630                 s->size = xsize_t(st.st_size);
3631                 if (!s->size)
3632                         goto empty;
3633                 if (S_ISLNK(st.st_mode)) {
3634                         struct strbuf sb = STRBUF_INIT;
3635
3636                         if (strbuf_readlink(&sb, s->path, s->size))
3637                                 goto err_empty;
3638                         s->size = sb.len;
3639                         s->data = strbuf_detach(&sb, NULL);
3640                         s->should_free = 1;
3641                         return 0;
3642                 }
3643
3644                 /*
3645                  * Even if the caller would be happy with getting
3646                  * only the size, we cannot return early at this
3647                  * point if the path requires us to run the content
3648                  * conversion.
3649                  */
3650                 if (size_only && !would_convert_to_git(&the_index, s->path))
3651                         return 0;
3652
3653                 /*
3654                  * Note: this check uses xsize_t(st.st_size) that may
3655                  * not be the true size of the blob after it goes
3656                  * through convert_to_git().  This may not strictly be
3657                  * correct, but the whole point of big_file_threshold
3658                  * and is_binary check being that we want to avoid
3659                  * opening the file and inspecting the contents, this
3660                  * is probably fine.
3661                  */
3662                 if ((flags & CHECK_BINARY) &&
3663                     s->size > big_file_threshold && s->is_binary == -1) {
3664                         s->is_binary = 1;
3665                         return 0;
3666                 }
3667                 fd = open(s->path, O_RDONLY);
3668                 if (fd < 0)
3669                         goto err_empty;
3670                 s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
3671                 close(fd);
3672                 s->should_munmap = 1;
3673
3674                 /*
3675                  * Convert from working tree format to canonical git format
3676                  */
3677                 if (convert_to_git(&the_index, s->path, s->data, s->size, &buf, crlf_warn)) {
3678                         size_t size = 0;
3679                         munmap(s->data, s->size);
3680                         s->should_munmap = 0;
3681                         s->data = strbuf_detach(&buf, &size);
3682                         s->size = size;
3683                         s->should_free = 1;
3684                 }
3685         }
3686         else {
3687                 enum object_type type;
3688                 if (size_only || (flags & CHECK_BINARY)) {
3689                         type = sha1_object_info(s->oid.hash, &s->size);
3690                         if (type < 0)
3691                                 die("unable to read %s",
3692                                     oid_to_hex(&s->oid));
3693                         if (size_only)
3694                                 return 0;
3695                         if (s->size > big_file_threshold && s->is_binary == -1) {
3696                                 s->is_binary = 1;
3697                                 return 0;
3698                         }
3699                 }
3700                 s->data = read_sha1_file(s->oid.hash, &type, &s->size);
3701                 if (!s->data)
3702                         die("unable to read %s", oid_to_hex(&s->oid));
3703                 s->should_free = 1;
3704         }
3705         return 0;
3706 }
3707
3708 void diff_free_filespec_blob(struct diff_filespec *s)
3709 {
3710         if (s->should_free)
3711                 free(s->data);
3712         else if (s->should_munmap)
3713                 munmap(s->data, s->size);
3714
3715         if (s->should_free || s->should_munmap) {
3716                 s->should_free = s->should_munmap = 0;
3717                 s->data = NULL;
3718         }
3719 }
3720
3721 void diff_free_filespec_data(struct diff_filespec *s)
3722 {
3723         diff_free_filespec_blob(s);
3724         FREE_AND_NULL(s->cnt_data);
3725 }
3726
3727 static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
3728                            void *blob,
3729                            unsigned long size,
3730                            const struct object_id *oid,
3731                            int mode)
3732 {
3733         int fd;
3734         struct strbuf buf = STRBUF_INIT;
3735         struct strbuf template = STRBUF_INIT;
3736         char *path_dup = xstrdup(path);
3737         const char *base = basename(path_dup);
3738
3739         /* Generate "XXXXXX_basename.ext" */
3740         strbuf_addstr(&template, "XXXXXX_");
3741         strbuf_addstr(&template, base);
3742
3743         fd = mks_tempfile_ts(&temp->tempfile, template.buf, strlen(base) + 1);
3744         if (fd < 0)
3745                 die_errno("unable to create temp-file");
3746         if (convert_to_working_tree(path,
3747                         (const char *)blob, (size_t)size, &buf)) {
3748                 blob = buf.buf;
3749                 size = buf.len;
3750         }
3751         if (write_in_full(fd, blob, size) != size)
3752                 die_errno("unable to write temp-file");
3753         close_tempfile(&temp->tempfile);
3754         temp->name = get_tempfile_path(&temp->tempfile);
3755         oid_to_hex_r(temp->hex, oid);
3756         xsnprintf(temp->mode, sizeof(temp->mode), "%06o", mode);
3757         strbuf_release(&buf);
3758         strbuf_release(&template);
3759         free(path_dup);
3760 }
3761
3762 static struct diff_tempfile *prepare_temp_file(const char *name,
3763                 struct diff_filespec *one)
3764 {
3765         struct diff_tempfile *temp = claim_diff_tempfile();
3766
3767         if (!DIFF_FILE_VALID(one)) {
3768         not_a_valid_file:
3769                 /* A '-' entry produces this for file-2, and
3770                  * a '+' entry produces this for file-1.
3771                  */
3772                 temp->name = "/dev/null";
3773                 xsnprintf(temp->hex, sizeof(temp->hex), ".");
3774                 xsnprintf(temp->mode, sizeof(temp->mode), ".");
3775                 return temp;
3776         }
3777
3778         if (!S_ISGITLINK(one->mode) &&
3779             (!one->oid_valid ||
3780              reuse_worktree_file(name, &one->oid, 1))) {
3781                 struct stat st;
3782                 if (lstat(name, &st) < 0) {
3783                         if (errno == ENOENT)
3784                                 goto not_a_valid_file;
3785                         die_errno("stat(%s)", name);
3786                 }
3787                 if (S_ISLNK(st.st_mode)) {
3788                         struct strbuf sb = STRBUF_INIT;
3789                         if (strbuf_readlink(&sb, name, st.st_size) < 0)
3790                                 die_errno("readlink(%s)", name);
3791                         prep_temp_blob(name, temp, sb.buf, sb.len,
3792                                        (one->oid_valid ?
3793                                         &one->oid : &null_oid),
3794                                        (one->oid_valid ?
3795                                         one->mode : S_IFLNK));
3796                         strbuf_release(&sb);
3797                 }
3798                 else {
3799                         /* we can borrow from the file in the work tree */
3800                         temp->name = name;
3801                         if (!one->oid_valid)
3802                                 oid_to_hex_r(temp->hex, &null_oid);
3803                         else
3804                                 oid_to_hex_r(temp->hex, &one->oid);
3805                         /* Even though we may sometimes borrow the
3806                          * contents from the work tree, we always want
3807                          * one->mode.  mode is trustworthy even when
3808                          * !(one->oid_valid), as long as
3809                          * DIFF_FILE_VALID(one).
3810                          */
3811                         xsnprintf(temp->mode, sizeof(temp->mode), "%06o", one->mode);
3812                 }
3813                 return temp;
3814         }
3815         else {
3816                 if (diff_populate_filespec(one, 0))
3817                         die("cannot read data blob for %s", one->path);
3818                 prep_temp_blob(name, temp, one->data, one->size,
3819                                &one->oid, one->mode);
3820         }
3821         return temp;
3822 }
3823
3824 static void add_external_diff_name(struct argv_array *argv,
3825                                    const char *name,
3826                                    struct diff_filespec *df)
3827 {
3828         struct diff_tempfile *temp = prepare_temp_file(name, df);
3829         argv_array_push(argv, temp->name);
3830         argv_array_push(argv, temp->hex);
3831         argv_array_push(argv, temp->mode);
3832 }
3833
3834 /* An external diff command takes:
3835  *
3836  * diff-cmd name infile1 infile1-sha1 infile1-mode \
3837  *               infile2 infile2-sha1 infile2-mode [ rename-to ]
3838  *
3839  */
3840 static void run_external_diff(const char *pgm,
3841                               const char *name,
3842                               const char *other,
3843                               struct diff_filespec *one,
3844                               struct diff_filespec *two,
3845                               const char *xfrm_msg,
3846                               int complete_rewrite,
3847                               struct diff_options *o)
3848 {
3849         struct argv_array argv = ARGV_ARRAY_INIT;
3850         struct argv_array env = ARGV_ARRAY_INIT;
3851         struct diff_queue_struct *q = &diff_queued_diff;
3852
3853         argv_array_push(&argv, pgm);
3854         argv_array_push(&argv, name);
3855
3856         if (one && two) {
3857                 add_external_diff_name(&argv, name, one);
3858                 if (!other)
3859                         add_external_diff_name(&argv, name, two);
3860                 else {
3861                         add_external_diff_name(&argv, other, two);
3862                         argv_array_push(&argv, other);
3863                         argv_array_push(&argv, xfrm_msg);
3864                 }
3865         }
3866
3867         argv_array_pushf(&env, "GIT_DIFF_PATH_COUNTER=%d", ++o->diff_path_counter);
3868         argv_array_pushf(&env, "GIT_DIFF_PATH_TOTAL=%d", q->nr);
3869
3870         if (run_command_v_opt_cd_env(argv.argv, RUN_USING_SHELL, NULL, env.argv))
3871                 die(_("external diff died, stopping at %s"), name);
3872
3873         remove_tempfile();
3874         argv_array_clear(&argv);
3875         argv_array_clear(&env);
3876 }
3877
3878 static int similarity_index(struct diff_filepair *p)
3879 {
3880         return p->score * 100 / MAX_SCORE;
3881 }
3882
3883 static const char *diff_abbrev_oid(const struct object_id *oid, int abbrev)
3884 {
3885         if (startup_info->have_repository)
3886                 return find_unique_abbrev(oid->hash, abbrev);
3887         else {
3888                 char *hex = oid_to_hex(oid);
3889                 if (abbrev < 0)
3890                         abbrev = FALLBACK_DEFAULT_ABBREV;
3891                 if (abbrev > GIT_SHA1_HEXSZ)
3892                         die("BUG: oid abbreviation out of range: %d", abbrev);
3893                 if (abbrev)
3894                         hex[abbrev] = '\0';
3895                 return hex;
3896         }
3897 }
3898
3899 static void fill_metainfo(struct strbuf *msg,
3900                           const char *name,
3901                           const char *other,
3902                           struct diff_filespec *one,
3903                           struct diff_filespec *two,
3904                           struct diff_options *o,
3905                           struct diff_filepair *p,
3906                           int *must_show_header,
3907                           int use_color)
3908 {
3909         const char *set = diff_get_color(use_color, DIFF_METAINFO);
3910         const char *reset = diff_get_color(use_color, DIFF_RESET);
3911         const char *line_prefix = diff_line_prefix(o);
3912
3913         *must_show_header = 1;
3914         strbuf_init(msg, PATH_MAX * 2 + 300);
3915         switch (p->status) {
3916         case DIFF_STATUS_COPIED:
3917                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
3918                             line_prefix, set, similarity_index(p));
3919                 strbuf_addf(msg, "%s\n%s%scopy from ",
3920                             reset,  line_prefix, set);
3921                 quote_c_style(name, msg, NULL, 0);
3922                 strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
3923                 quote_c_style(other, msg, NULL, 0);
3924                 strbuf_addf(msg, "%s\n", reset);
3925                 break;
3926         case DIFF_STATUS_RENAMED:
3927                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
3928                             line_prefix, set, similarity_index(p));
3929                 strbuf_addf(msg, "%s\n%s%srename from ",
3930                             reset, line_prefix, set);
3931                 quote_c_style(name, msg, NULL, 0);
3932                 strbuf_addf(msg, "%s\n%s%srename to ",
3933                             reset, line_prefix, set);
3934                 quote_c_style(other, msg, NULL, 0);
3935                 strbuf_addf(msg, "%s\n", reset);
3936                 break;
3937         case DIFF_STATUS_MODIFIED:
3938                 if (p->score) {
3939                         strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
3940                                     line_prefix,
3941                                     set, similarity_index(p), reset);
3942                         break;
3943                 }
3944                 /* fallthru */
3945         default:
3946                 *must_show_header = 0;
3947         }
3948         if (one && two && oidcmp(&one->oid, &two->oid)) {
3949                 int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
3950
3951                 if (DIFF_OPT_TST(o, BINARY)) {
3952                         mmfile_t mf;
3953                         if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
3954                             (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
3955                                 abbrev = 40;
3956                 }
3957                 strbuf_addf(msg, "%s%sindex %s..%s", line_prefix, set,
3958                             diff_abbrev_oid(&one->oid, abbrev),
3959                             diff_abbrev_oid(&two->oid, abbrev));
3960                 if (one->mode == two->mode)
3961                         strbuf_addf(msg, " %06o", one->mode);
3962                 strbuf_addf(msg, "%s\n", reset);
3963         }
3964 }
3965
3966 static void run_diff_cmd(const char *pgm,
3967                          const char *name,
3968                          const char *other,
3969                          const char *attr_path,
3970                          struct diff_filespec *one,
3971                          struct diff_filespec *two,
3972                          struct strbuf *msg,
3973                          struct diff_options *o,
3974                          struct diff_filepair *p)
3975 {
3976         const char *xfrm_msg = NULL;
3977         int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
3978         int must_show_header = 0;
3979
3980
3981         if (DIFF_OPT_TST(o, ALLOW_EXTERNAL)) {
3982                 struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
3983                 if (drv && drv->external)
3984                         pgm = drv->external;
3985         }
3986
3987         if (msg) {
3988                 /*
3989                  * don't use colors when the header is intended for an
3990                  * external diff driver
3991                  */
3992                 fill_metainfo(msg, name, other, one, two, o, p,
3993                               &must_show_header,
3994                               want_color(o->use_color) && !pgm);
3995                 xfrm_msg = msg->len ? msg->buf : NULL;
3996         }
3997
3998         if (pgm) {
3999                 run_external_diff(pgm, name, other, one, two, xfrm_msg,
4000                                   complete_rewrite, o);
4001                 return;
4002         }
4003         if (one && two)
4004                 builtin_diff(name, other ? other : name,
4005                              one, two, xfrm_msg, must_show_header,
4006                              o, complete_rewrite);
4007         else
4008                 fprintf(o->file, "* Unmerged path %s\n", name);
4009 }
4010
4011 static void diff_fill_oid_info(struct diff_filespec *one)
4012 {
4013         if (DIFF_FILE_VALID(one)) {
4014                 if (!one->oid_valid) {
4015                         struct stat st;
4016                         if (one->is_stdin) {
4017                                 oidclr(&one->oid);
4018                                 return;
4019                         }
4020                         if (lstat(one->path, &st) < 0)
4021                                 die_errno("stat '%s'", one->path);
4022                         if (index_path(one->oid.hash, one->path, &st, 0))
4023                                 die("cannot hash %s", one->path);
4024                 }
4025         }
4026         else
4027                 oidclr(&one->oid);
4028 }
4029
4030 static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
4031 {
4032         /* Strip the prefix but do not molest /dev/null and absolute paths */
4033         if (*namep && **namep != '/') {
4034                 *namep += prefix_length;
4035                 if (**namep == '/')
4036                         ++*namep;
4037         }
4038         if (*otherp && **otherp != '/') {
4039                 *otherp += prefix_length;
4040                 if (**otherp == '/')
4041                         ++*otherp;
4042         }
4043 }
4044
4045 static void run_diff(struct diff_filepair *p, struct diff_options *o)
4046 {
4047         const char *pgm = external_diff();
4048         struct strbuf msg;
4049         struct diff_filespec *one = p->one;
4050         struct diff_filespec *two = p->two;
4051         const char *name;
4052         const char *other;
4053         const char *attr_path;
4054
4055         name  = one->path;
4056         other = (strcmp(name, two->path) ? two->path : NULL);
4057         attr_path = name;
4058         if (o->prefix_length)
4059                 strip_prefix(o->prefix_length, &name, &other);
4060
4061         if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
4062                 pgm = NULL;
4063
4064         if (DIFF_PAIR_UNMERGED(p)) {
4065                 run_diff_cmd(pgm, name, NULL, attr_path,
4066                              NULL, NULL, NULL, o, p);
4067                 return;
4068         }
4069
4070         diff_fill_oid_info(one);
4071         diff_fill_oid_info(two);
4072
4073         if (!pgm &&
4074             DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
4075             (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
4076                 /*
4077                  * a filepair that changes between file and symlink
4078                  * needs to be split into deletion and creation.
4079                  */
4080                 struct diff_filespec *null = alloc_filespec(two->path);
4081                 run_diff_cmd(NULL, name, other, attr_path,
4082                              one, null, &msg, o, p);
4083                 free(null);
4084                 strbuf_release(&msg);
4085
4086                 null = alloc_filespec(one->path);
4087                 run_diff_cmd(NULL, name, other, attr_path,
4088                              null, two, &msg, o, p);
4089                 free(null);
4090         }
4091         else
4092                 run_diff_cmd(pgm, name, other, attr_path,
4093                              one, two, &msg, o, p);
4094
4095         strbuf_release(&msg);
4096 }
4097
4098 static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
4099                          struct diffstat_t *diffstat)
4100 {
4101         const char *name;
4102         const char *other;
4103
4104         if (DIFF_PAIR_UNMERGED(p)) {
4105                 /* unmerged */
4106                 builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, p);
4107                 return;
4108         }
4109
4110         name = p->one->path;
4111         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
4112
4113         if (o->prefix_length)
4114                 strip_prefix(o->prefix_length, &name, &other);
4115
4116         diff_fill_oid_info(p->one);
4117         diff_fill_oid_info(p->two);
4118
4119         builtin_diffstat(name, other, p->one, p->two, diffstat, o, p);
4120 }
4121
4122 static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
4123 {
4124         const char *name;
4125         const char *other;
4126         const char *attr_path;
4127
4128         if (DIFF_PAIR_UNMERGED(p)) {
4129                 /* unmerged */
4130                 return;
4131         }
4132
4133         name = p->one->path;
4134         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
4135         attr_path = other ? other : name;
4136
4137         if (o->prefix_length)
4138                 strip_prefix(o->prefix_length, &name, &other);
4139
4140         diff_fill_oid_info(p->one);
4141         diff_fill_oid_info(p->two);
4142
4143         builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
4144 }
4145
4146 void diff_setup(struct diff_options *options)
4147 {
4148         memcpy(options, &default_diff_options, sizeof(*options));
4149
4150         options->file = stdout;
4151
4152         options->abbrev = DEFAULT_ABBREV;
4153         options->line_termination = '\n';
4154         options->break_opt = -1;
4155         options->rename_limit = -1;
4156         options->dirstat_permille = diff_dirstat_permille_default;
4157         options->context = diff_context_default;
4158         options->interhunkcontext = diff_interhunk_context_default;
4159         options->ws_error_highlight = ws_error_highlight_default;
4160         DIFF_OPT_SET(options, RENAME_EMPTY);
4161
4162         /* pathchange left =NULL by default */
4163         options->change = diff_change;
4164         options->add_remove = diff_addremove;
4165         options->use_color = diff_use_color_default;
4166         options->detect_rename = diff_detect_rename_default;
4167         options->xdl_opts |= diff_algorithm;
4168         if (diff_indent_heuristic)
4169                 DIFF_XDL_SET(options, INDENT_HEURISTIC);
4170
4171         options->orderfile = diff_order_file_cfg;
4172
4173         if (diff_no_prefix) {
4174                 options->a_prefix = options->b_prefix = "";
4175         } else if (!diff_mnemonic_prefix) {
4176                 options->a_prefix = "a/";
4177                 options->b_prefix = "b/";
4178         }
4179
4180         options->color_moved = diff_color_moved_default;
4181 }
4182
4183 void diff_setup_done(struct diff_options *options)
4184 {
4185         int count = 0;
4186
4187         if (options->set_default)
4188                 options->set_default(options);
4189
4190         if (options->output_format & DIFF_FORMAT_NAME)
4191                 count++;
4192         if (options->output_format & DIFF_FORMAT_NAME_STATUS)
4193                 count++;
4194         if (options->output_format & DIFF_FORMAT_CHECKDIFF)
4195                 count++;
4196         if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
4197                 count++;
4198         if (count > 1)
4199                 die(_("--name-only, --name-status, --check and -s are mutually exclusive"));
4200
4201         /*
4202          * Most of the time we can say "there are changes"
4203          * only by checking if there are changed paths, but
4204          * --ignore-whitespace* options force us to look
4205          * inside contents.
4206          */
4207
4208         if (DIFF_XDL_TST(options, IGNORE_WHITESPACE) ||
4209             DIFF_XDL_TST(options, IGNORE_WHITESPACE_CHANGE) ||
4210             DIFF_XDL_TST(options, IGNORE_WHITESPACE_AT_EOL))
4211                 DIFF_OPT_SET(options, DIFF_FROM_CONTENTS);
4212         else
4213                 DIFF_OPT_CLR(options, DIFF_FROM_CONTENTS);
4214
4215         if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
4216                 options->detect_rename = DIFF_DETECT_COPY;
4217
4218         if (!DIFF_OPT_TST(options, RELATIVE_NAME))
4219                 options->prefix = NULL;
4220         if (options->prefix)
4221                 options->prefix_length = strlen(options->prefix);
4222         else
4223                 options->prefix_length = 0;
4224
4225         if (options->output_format & (DIFF_FORMAT_NAME |
4226                                       DIFF_FORMAT_NAME_STATUS |
4227                                       DIFF_FORMAT_CHECKDIFF |
4228                                       DIFF_FORMAT_NO_OUTPUT))
4229                 options->output_format &= ~(DIFF_FORMAT_RAW |
4230                                             DIFF_FORMAT_NUMSTAT |
4231                                             DIFF_FORMAT_DIFFSTAT |
4232                                             DIFF_FORMAT_SHORTSTAT |
4233                                             DIFF_FORMAT_DIRSTAT |
4234                                             DIFF_FORMAT_SUMMARY |
4235                                             DIFF_FORMAT_PATCH);
4236
4237         /*
4238          * These cases always need recursive; we do not drop caller-supplied
4239          * recursive bits for other formats here.
4240          */
4241         if (options->output_format & (DIFF_FORMAT_PATCH |
4242                                       DIFF_FORMAT_NUMSTAT |
4243                                       DIFF_FORMAT_DIFFSTAT |
4244                                       DIFF_FORMAT_SHORTSTAT |
4245                                       DIFF_FORMAT_DIRSTAT |
4246                                       DIFF_FORMAT_SUMMARY |
4247                                       DIFF_FORMAT_CHECKDIFF))
4248                 DIFF_OPT_SET(options, RECURSIVE);
4249         /*
4250          * Also pickaxe would not work very well if you do not say recursive
4251          */
4252         if (options->pickaxe)
4253                 DIFF_OPT_SET(options, RECURSIVE);
4254         /*
4255          * When patches are generated, submodules diffed against the work tree
4256          * must be checked for dirtiness too so it can be shown in the output
4257          */
4258         if (options->output_format & DIFF_FORMAT_PATCH)
4259                 DIFF_OPT_SET(options, DIRTY_SUBMODULES);
4260
4261         if (options->detect_rename && options->rename_limit < 0)
4262                 options->rename_limit = diff_rename_limit_default;
4263         if (options->setup & DIFF_SETUP_USE_CACHE) {
4264                 if (!active_cache)
4265                         /* read-cache does not die even when it fails
4266                          * so it is safe for us to do this here.  Also
4267                          * it does not smudge active_cache or active_nr
4268                          * when it fails, so we do not have to worry about
4269                          * cleaning it up ourselves either.
4270                          */
4271                         read_cache();
4272         }
4273         if (40 < options->abbrev)
4274                 options->abbrev = 40; /* full */
4275
4276         /*
4277          * It does not make sense to show the first hit we happened
4278          * to have found.  It does not make sense not to return with
4279          * exit code in such a case either.
4280          */
4281         if (DIFF_OPT_TST(options, QUICK)) {
4282                 options->output_format = DIFF_FORMAT_NO_OUTPUT;
4283                 DIFF_OPT_SET(options, EXIT_WITH_STATUS);
4284         }
4285
4286         options->diff_path_counter = 0;
4287
4288         if (DIFF_OPT_TST(options, FOLLOW_RENAMES) && options->pathspec.nr != 1)
4289                 die(_("--follow requires exactly one pathspec"));
4290
4291         if (!options->use_color || external_diff())
4292                 options->color_moved = 0;
4293 }
4294
4295 static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
4296 {
4297         char c, *eq;
4298         int len;
4299
4300         if (*arg != '-')
4301                 return 0;
4302         c = *++arg;
4303         if (!c)
4304                 return 0;
4305         if (c == arg_short) {
4306                 c = *++arg;
4307                 if (!c)
4308                         return 1;
4309                 if (val && isdigit(c)) {
4310                         char *end;
4311                         int n = strtoul(arg, &end, 10);
4312                         if (*end)
4313                                 return 0;
4314                         *val = n;
4315                         return 1;
4316                 }
4317                 return 0;
4318         }
4319         if (c != '-')
4320                 return 0;
4321         arg++;
4322         eq = strchrnul(arg, '=');
4323         len = eq - arg;
4324         if (!len || strncmp(arg, arg_long, len))
4325                 return 0;
4326         if (*eq) {
4327                 int n;
4328                 char *end;
4329                 if (!isdigit(*++eq))
4330                         return 0;
4331                 n = strtoul(eq, &end, 10);
4332                 if (*end)
4333                         return 0;
4334                 *val = n;
4335         }
4336         return 1;
4337 }
4338
4339 static int diff_scoreopt_parse(const char *opt);
4340
4341 static inline int short_opt(char opt, const char **argv,
4342                             const char **optarg)
4343 {
4344         const char *arg = argv[0];
4345         if (arg[0] != '-' || arg[1] != opt)
4346                 return 0;
4347         if (arg[2] != '\0') {
4348                 *optarg = arg + 2;
4349                 return 1;
4350         }
4351         if (!argv[1])
4352                 die("Option '%c' requires a value", opt);
4353         *optarg = argv[1];
4354         return 2;
4355 }
4356
4357 int parse_long_opt(const char *opt, const char **argv,
4358                    const char **optarg)
4359 {
4360         const char *arg = argv[0];
4361         if (!skip_prefix(arg, "--", &arg))
4362                 return 0;
4363         if (!skip_prefix(arg, opt, &arg))
4364                 return 0;
4365         if (*arg == '=') { /* stuck form: --option=value */
4366                 *optarg = arg + 1;
4367                 return 1;
4368         }
4369         if (*arg != '\0')
4370                 return 0;
4371         /* separate form: --option value */
4372         if (!argv[1])
4373                 die("Option '--%s' requires a value", opt);
4374         *optarg = argv[1];
4375         return 2;
4376 }
4377
4378 static int stat_opt(struct diff_options *options, const char **av)
4379 {
4380         const char *arg = av[0];
4381         char *end;
4382         int width = options->stat_width;
4383         int name_width = options->stat_name_width;
4384         int graph_width = options->stat_graph_width;
4385         int count = options->stat_count;
4386         int argcount = 1;
4387
4388         if (!skip_prefix(arg, "--stat", &arg))
4389                 die("BUG: stat option does not begin with --stat: %s", arg);
4390         end = (char *)arg;
4391
4392         switch (*arg) {
4393         case '-':
4394                 if (skip_prefix(arg, "-width", &arg)) {
4395                         if (*arg == '=')
4396                                 width = strtoul(arg + 1, &end, 10);
4397                         else if (!*arg && !av[1])
4398                                 die_want_option("--stat-width");
4399                         else if (!*arg) {
4400                                 width = strtoul(av[1], &end, 10);
4401                                 argcount = 2;
4402                         }
4403                 } else if (skip_prefix(arg, "-name-width", &arg)) {
4404                         if (*arg == '=')
4405                                 name_width = strtoul(arg + 1, &end, 10);
4406                         else if (!*arg && !av[1])
4407                                 die_want_option("--stat-name-width");
4408                         else if (!*arg) {
4409                                 name_width = strtoul(av[1], &end, 10);
4410                                 argcount = 2;
4411                         }
4412                 } else if (skip_prefix(arg, "-graph-width", &arg)) {
4413                         if (*arg == '=')
4414                                 graph_width = strtoul(arg + 1, &end, 10);
4415                         else if (!*arg && !av[1])
4416                                 die_want_option("--stat-graph-width");
4417                         else if (!*arg) {
4418                                 graph_width = strtoul(av[1], &end, 10);
4419                                 argcount = 2;
4420                         }
4421                 } else if (skip_prefix(arg, "-count", &arg)) {
4422                         if (*arg == '=')
4423                                 count = strtoul(arg + 1, &end, 10);
4424                         else if (!*arg && !av[1])
4425                                 die_want_option("--stat-count");
4426                         else if (!*arg) {
4427                                 count = strtoul(av[1], &end, 10);
4428                                 argcount = 2;
4429                         }
4430                 }
4431                 break;
4432         case '=':
4433                 width = strtoul(arg+1, &end, 10);
4434                 if (*end == ',')
4435                         name_width = strtoul(end+1, &end, 10);
4436                 if (*end == ',')
4437                         count = strtoul(end+1, &end, 10);
4438         }
4439
4440         /* Important! This checks all the error cases! */
4441         if (*end)
4442                 return 0;
4443         options->output_format |= DIFF_FORMAT_DIFFSTAT;
4444         options->stat_name_width = name_width;
4445         options->stat_graph_width = graph_width;
4446         options->stat_width = width;
4447         options->stat_count = count;
4448         return argcount;
4449 }
4450
4451 static int parse_dirstat_opt(struct diff_options *options, const char *params)
4452 {
4453         struct strbuf errmsg = STRBUF_INIT;
4454         if (parse_dirstat_params(options, params, &errmsg))
4455                 die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
4456                     errmsg.buf);
4457         strbuf_release(&errmsg);
4458         /*
4459          * The caller knows a dirstat-related option is given from the command
4460          * line; allow it to say "return this_function();"
4461          */
4462         options->output_format |= DIFF_FORMAT_DIRSTAT;
4463         return 1;
4464 }
4465
4466 static int parse_submodule_opt(struct diff_options *options, const char *value)
4467 {
4468         if (parse_submodule_params(options, value))
4469                 die(_("Failed to parse --submodule option parameter: '%s'"),
4470                         value);
4471         return 1;
4472 }
4473
4474 static const char diff_status_letters[] = {
4475         DIFF_STATUS_ADDED,
4476         DIFF_STATUS_COPIED,
4477         DIFF_STATUS_DELETED,
4478         DIFF_STATUS_MODIFIED,
4479         DIFF_STATUS_RENAMED,
4480         DIFF_STATUS_TYPE_CHANGED,
4481         DIFF_STATUS_UNKNOWN,
4482         DIFF_STATUS_UNMERGED,
4483         DIFF_STATUS_FILTER_AON,
4484         DIFF_STATUS_FILTER_BROKEN,
4485         '\0',
4486 };
4487
4488 static unsigned int filter_bit['Z' + 1];
4489
4490 static void prepare_filter_bits(void)
4491 {
4492         int i;
4493
4494         if (!filter_bit[DIFF_STATUS_ADDED]) {
4495                 for (i = 0; diff_status_letters[i]; i++)
4496                         filter_bit[(int) diff_status_letters[i]] = (1 << i);
4497         }
4498 }
4499
4500 static unsigned filter_bit_tst(char status, const struct diff_options *opt)
4501 {
4502         return opt->filter & filter_bit[(int) status];
4503 }
4504
4505 static int parse_diff_filter_opt(const char *optarg, struct diff_options *opt)
4506 {
4507         int i, optch;
4508
4509         prepare_filter_bits();
4510
4511         /*
4512          * If there is a negation e.g. 'd' in the input, and we haven't
4513          * initialized the filter field with another --diff-filter, start
4514          * from full set of bits, except for AON.
4515          */
4516         if (!opt->filter) {
4517                 for (i = 0; (optch = optarg[i]) != '\0'; i++) {
4518                         if (optch < 'a' || 'z' < optch)
4519                                 continue;
4520                         opt->filter = (1 << (ARRAY_SIZE(diff_status_letters) - 1)) - 1;
4521                         opt->filter &= ~filter_bit[DIFF_STATUS_FILTER_AON];
4522                         break;
4523                 }
4524         }
4525
4526         for (i = 0; (optch = optarg[i]) != '\0'; i++) {
4527                 unsigned int bit;
4528                 int negate;
4529
4530                 if ('a' <= optch && optch <= 'z') {
4531                         negate = 1;
4532                         optch = toupper(optch);
4533                 } else {
4534                         negate = 0;
4535                 }
4536
4537                 bit = (0 <= optch && optch <= 'Z') ? filter_bit[optch] : 0;
4538                 if (!bit)
4539                         return optarg[i];
4540                 if (negate)
4541                         opt->filter &= ~bit;
4542                 else
4543                         opt->filter |= bit;
4544         }
4545         return 0;
4546 }
4547
4548 static void enable_patch_output(int *fmt) {
4549         *fmt &= ~DIFF_FORMAT_NO_OUTPUT;
4550         *fmt |= DIFF_FORMAT_PATCH;
4551 }
4552
4553 static int parse_ws_error_highlight_opt(struct diff_options *opt, const char *arg)
4554 {
4555         int val = parse_ws_error_highlight(arg);
4556
4557         if (val < 0) {
4558                 error("unknown value after ws-error-highlight=%.*s",
4559                       -1 - val, arg);
4560                 return 0;
4561         }
4562         opt->ws_error_highlight = val;
4563         return 1;
4564 }
4565
4566 int diff_opt_parse(struct diff_options *options,
4567                    const char **av, int ac, const char *prefix)
4568 {
4569         const char *arg = av[0];
4570         const char *optarg;
4571         int argcount;
4572
4573         if (!prefix)
4574                 prefix = "";
4575
4576         /* Output format options */
4577         if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch")
4578             || opt_arg(arg, 'U', "unified", &options->context))
4579                 enable_patch_output(&options->output_format);
4580         else if (!strcmp(arg, "--raw"))
4581                 options->output_format |= DIFF_FORMAT_RAW;
4582         else if (!strcmp(arg, "--patch-with-raw")) {
4583                 enable_patch_output(&options->output_format);
4584                 options->output_format |= DIFF_FORMAT_RAW;
4585         } else if (!strcmp(arg, "--numstat"))
4586                 options->output_format |= DIFF_FORMAT_NUMSTAT;
4587         else if (!strcmp(arg, "--shortstat"))
4588                 options->output_format |= DIFF_FORMAT_SHORTSTAT;
4589         else if (!strcmp(arg, "-X") || !strcmp(arg, "--dirstat"))
4590                 return parse_dirstat_opt(options, "");
4591         else if (skip_prefix(arg, "-X", &arg))
4592                 return parse_dirstat_opt(options, arg);
4593         else if (skip_prefix(arg, "--dirstat=", &arg))
4594                 return parse_dirstat_opt(options, arg);
4595         else if (!strcmp(arg, "--cumulative"))
4596                 return parse_dirstat_opt(options, "cumulative");
4597         else if (!strcmp(arg, "--dirstat-by-file"))
4598                 return parse_dirstat_opt(options, "files");
4599         else if (skip_prefix(arg, "--dirstat-by-file=", &arg)) {
4600                 parse_dirstat_opt(options, "files");
4601                 return parse_dirstat_opt(options, arg);
4602         }
4603         else if (!strcmp(arg, "--check"))
4604                 options->output_format |= DIFF_FORMAT_CHECKDIFF;
4605         else if (!strcmp(arg, "--summary"))
4606                 options->output_format |= DIFF_FORMAT_SUMMARY;
4607         else if (!strcmp(arg, "--patch-with-stat")) {
4608                 enable_patch_output(&options->output_format);
4609                 options->output_format |= DIFF_FORMAT_DIFFSTAT;
4610         } else if (!strcmp(arg, "--name-only"))
4611                 options->output_format |= DIFF_FORMAT_NAME;
4612         else if (!strcmp(arg, "--name-status"))
4613                 options->output_format |= DIFF_FORMAT_NAME_STATUS;
4614         else if (!strcmp(arg, "-s") || !strcmp(arg, "--no-patch"))
4615                 options->output_format |= DIFF_FORMAT_NO_OUTPUT;
4616         else if (starts_with(arg, "--stat"))
4617                 /* --stat, --stat-width, --stat-name-width, or --stat-count */
4618                 return stat_opt(options, av);
4619
4620         /* renames options */
4621         else if (starts_with(arg, "-B") || starts_with(arg, "--break-rewrites=") ||
4622                  !strcmp(arg, "--break-rewrites")) {
4623                 if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
4624                         return error("invalid argument to -B: %s", arg+2);
4625         }
4626         else if (starts_with(arg, "-M") || starts_with(arg, "--find-renames=") ||
4627                  !strcmp(arg, "--find-renames")) {
4628                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
4629                         return error("invalid argument to -M: %s", arg+2);
4630                 options->detect_rename = DIFF_DETECT_RENAME;
4631         }
4632         else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
4633                 options->irreversible_delete = 1;
4634         }
4635         else if (starts_with(arg, "-C") || starts_with(arg, "--find-copies=") ||
4636                  !strcmp(arg, "--find-copies")) {
4637                 if (options->detect_rename == DIFF_DETECT_COPY)
4638                         DIFF_OPT_SET(options, FIND_COPIES_HARDER);
4639                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
4640                         return error("invalid argument to -C: %s", arg+2);
4641                 options->detect_rename = DIFF_DETECT_COPY;
4642         }
4643         else if (!strcmp(arg, "--no-renames"))
4644                 options->detect_rename = 0;
4645         else if (!strcmp(arg, "--rename-empty"))
4646                 DIFF_OPT_SET(options, RENAME_EMPTY);
4647         else if (!strcmp(arg, "--no-rename-empty"))
4648                 DIFF_OPT_CLR(options, RENAME_EMPTY);
4649         else if (!strcmp(arg, "--relative"))
4650                 DIFF_OPT_SET(options, RELATIVE_NAME);
4651         else if (skip_prefix(arg, "--relative=", &arg)) {
4652                 DIFF_OPT_SET(options, RELATIVE_NAME);
4653                 options->prefix = arg;
4654         }
4655
4656         /* xdiff options */
4657         else if (!strcmp(arg, "--minimal"))
4658                 DIFF_XDL_SET(options, NEED_MINIMAL);
4659         else if (!strcmp(arg, "--no-minimal"))
4660                 DIFF_XDL_CLR(options, NEED_MINIMAL);
4661         else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
4662                 DIFF_XDL_SET(options, IGNORE_WHITESPACE);
4663         else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
4664                 DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
4665         else if (!strcmp(arg, "--ignore-space-at-eol"))
4666                 DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
4667         else if (!strcmp(arg, "--ignore-blank-lines"))
4668                 DIFF_XDL_SET(options, IGNORE_BLANK_LINES);
4669         else if (!strcmp(arg, "--indent-heuristic"))
4670                 DIFF_XDL_SET(options, INDENT_HEURISTIC);
4671         else if (!strcmp(arg, "--no-indent-heuristic"))
4672                 DIFF_XDL_CLR(options, INDENT_HEURISTIC);
4673         else if (!strcmp(arg, "--patience"))
4674                 options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
4675         else if (!strcmp(arg, "--histogram"))
4676                 options->xdl_opts = DIFF_WITH_ALG(options, HISTOGRAM_DIFF);
4677         else if ((argcount = parse_long_opt("diff-algorithm", av, &optarg))) {
4678                 long value = parse_algorithm_value(optarg);
4679                 if (value < 0)
4680                         return error("option diff-algorithm accepts \"myers\", "
4681                                      "\"minimal\", \"patience\" and \"histogram\"");
4682                 /* clear out previous settings */
4683                 DIFF_XDL_CLR(options, NEED_MINIMAL);
4684                 options->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
4685                 options->xdl_opts |= value;
4686                 return argcount;
4687         }
4688
4689         /* flags options */
4690         else if (!strcmp(arg, "--binary")) {
4691                 enable_patch_output(&options->output_format);
4692                 DIFF_OPT_SET(options, BINARY);
4693         }
4694         else if (!strcmp(arg, "--full-index"))
4695                 DIFF_OPT_SET(options, FULL_INDEX);
4696         else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
4697                 DIFF_OPT_SET(options, TEXT);
4698         else if (!strcmp(arg, "-R"))
4699                 DIFF_OPT_SET(options, REVERSE_DIFF);
4700         else if (!strcmp(arg, "--find-copies-harder"))
4701                 DIFF_OPT_SET(options, FIND_COPIES_HARDER);
4702         else if (!strcmp(arg, "--follow"))
4703                 DIFF_OPT_SET(options, FOLLOW_RENAMES);
4704         else if (!strcmp(arg, "--no-follow")) {
4705                 DIFF_OPT_CLR(options, FOLLOW_RENAMES);
4706                 DIFF_OPT_CLR(options, DEFAULT_FOLLOW_RENAMES);
4707         } else if (!strcmp(arg, "--color"))
4708                 options->use_color = 1;
4709         else if (skip_prefix(arg, "--color=", &arg)) {
4710                 int value = git_config_colorbool(NULL, arg);
4711                 if (value < 0)
4712                         return error("option `color' expects \"always\", \"auto\", or \"never\"");
4713                 options->use_color = value;
4714         }
4715         else if (!strcmp(arg, "--no-color"))
4716                 options->use_color = 0;
4717         else if (!strcmp(arg, "--color-moved")) {
4718                 if (diff_color_moved_default)
4719                         options->color_moved = diff_color_moved_default;
4720                 if (options->color_moved == COLOR_MOVED_NO)
4721                         options->color_moved = COLOR_MOVED_DEFAULT;
4722         } else if (!strcmp(arg, "--no-color-moved"))
4723                 options->color_moved = COLOR_MOVED_NO;
4724         else if (skip_prefix(arg, "--color-moved=", &arg)) {
4725                 int cm = parse_color_moved(arg);
4726                 if (cm < 0)
4727                         die("bad --color-moved argument: %s", arg);
4728                 options->color_moved = cm;
4729         } else if (!strcmp(arg, "--color-words")) {
4730                 options->use_color = 1;
4731                 options->word_diff = DIFF_WORDS_COLOR;
4732         }
4733         else if (skip_prefix(arg, "--color-words=", &arg)) {
4734                 options->use_color = 1;
4735                 options->word_diff = DIFF_WORDS_COLOR;
4736                 options->word_regex = arg;
4737         }
4738         else if (!strcmp(arg, "--word-diff")) {
4739                 if (options->word_diff == DIFF_WORDS_NONE)
4740                         options->word_diff = DIFF_WORDS_PLAIN;
4741         }
4742         else if (skip_prefix(arg, "--word-diff=", &arg)) {
4743                 if (!strcmp(arg, "plain"))
4744                         options->word_diff = DIFF_WORDS_PLAIN;
4745                 else if (!strcmp(arg, "color")) {
4746                         options->use_color = 1;
4747                         options->word_diff = DIFF_WORDS_COLOR;
4748                 }
4749                 else if (!strcmp(arg, "porcelain"))
4750                         options->word_diff = DIFF_WORDS_PORCELAIN;
4751                 else if (!strcmp(arg, "none"))
4752                         options->word_diff = DIFF_WORDS_NONE;
4753                 else
4754                         die("bad --word-diff argument: %s", arg);
4755         }
4756         else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
4757                 if (options->word_diff == DIFF_WORDS_NONE)
4758                         options->word_diff = DIFF_WORDS_PLAIN;
4759                 options->word_regex = optarg;
4760                 return argcount;
4761         }
4762         else if (!strcmp(arg, "--exit-code"))
4763                 DIFF_OPT_SET(options, EXIT_WITH_STATUS);
4764         else if (!strcmp(arg, "--quiet"))
4765                 DIFF_OPT_SET(options, QUICK);
4766         else if (!strcmp(arg, "--ext-diff"))
4767                 DIFF_OPT_SET(options, ALLOW_EXTERNAL);
4768         else if (!strcmp(arg, "--no-ext-diff"))
4769                 DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
4770         else if (!strcmp(arg, "--textconv"))
4771                 DIFF_OPT_SET(options, ALLOW_TEXTCONV);
4772         else if (!strcmp(arg, "--no-textconv"))
4773                 DIFF_OPT_CLR(options, ALLOW_TEXTCONV);
4774         else if (!strcmp(arg, "--ignore-submodules")) {
4775                 DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
4776                 handle_ignore_submodules_arg(options, "all");
4777         } else if (skip_prefix(arg, "--ignore-submodules=", &arg)) {
4778                 DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
4779                 handle_ignore_submodules_arg(options, arg);
4780         } else if (!strcmp(arg, "--submodule"))
4781                 options->submodule_format = DIFF_SUBMODULE_LOG;
4782         else if (skip_prefix(arg, "--submodule=", &arg))
4783                 return parse_submodule_opt(options, arg);
4784         else if (skip_prefix(arg, "--ws-error-highlight=", &arg))
4785                 return parse_ws_error_highlight_opt(options, arg);
4786         else if (!strcmp(arg, "--ita-invisible-in-index"))
4787                 options->ita_invisible_in_index = 1;
4788         else if (!strcmp(arg, "--ita-visible-in-index"))
4789                 options->ita_invisible_in_index = 0;
4790
4791         /* misc options */
4792         else if (!strcmp(arg, "-z"))
4793                 options->line_termination = 0;
4794         else if ((argcount = short_opt('l', av, &optarg))) {
4795                 options->rename_limit = strtoul(optarg, NULL, 10);
4796                 return argcount;
4797         }
4798         else if ((argcount = short_opt('S', av, &optarg))) {
4799                 options->pickaxe = optarg;
4800                 options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
4801                 return argcount;
4802         } else if ((argcount = short_opt('G', av, &optarg))) {
4803                 options->pickaxe = optarg;
4804                 options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
4805                 return argcount;
4806         }
4807         else if (!strcmp(arg, "--pickaxe-all"))
4808                 options->pickaxe_opts |= DIFF_PICKAXE_ALL;
4809         else if (!strcmp(arg, "--pickaxe-regex"))
4810                 options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
4811         else if ((argcount = short_opt('O', av, &optarg))) {
4812                 options->orderfile = prefix_filename(prefix, optarg);
4813                 return argcount;
4814         }
4815         else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
4816                 int offending = parse_diff_filter_opt(optarg, options);
4817                 if (offending)
4818                         die("unknown change class '%c' in --diff-filter=%s",
4819                             offending, optarg);
4820                 return argcount;
4821         }
4822         else if (!strcmp(arg, "--no-abbrev"))
4823                 options->abbrev = 0;
4824         else if (!strcmp(arg, "--abbrev"))
4825                 options->abbrev = DEFAULT_ABBREV;
4826         else if (skip_prefix(arg, "--abbrev=", &arg)) {
4827                 options->abbrev = strtoul(arg, NULL, 10);
4828                 if (options->abbrev < MINIMUM_ABBREV)
4829                         options->abbrev = MINIMUM_ABBREV;
4830                 else if (40 < options->abbrev)
4831                         options->abbrev = 40;
4832         }
4833         else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
4834                 options->a_prefix = optarg;
4835                 return argcount;
4836         }
4837         else if ((argcount = parse_long_opt("line-prefix", av, &optarg))) {
4838                 options->line_prefix = optarg;
4839                 options->line_prefix_length = strlen(options->line_prefix);
4840                 graph_setup_line_prefix(options);
4841                 return argcount;
4842         }
4843         else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
4844                 options->b_prefix = optarg;
4845                 return argcount;
4846         }
4847         else if (!strcmp(arg, "--no-prefix"))
4848                 options->a_prefix = options->b_prefix = "";
4849         else if (opt_arg(arg, '\0', "inter-hunk-context",
4850                          &options->interhunkcontext))
4851                 ;
4852         else if (!strcmp(arg, "-W"))
4853                 DIFF_OPT_SET(options, FUNCCONTEXT);
4854         else if (!strcmp(arg, "--function-context"))
4855                 DIFF_OPT_SET(options, FUNCCONTEXT);
4856         else if (!strcmp(arg, "--no-function-context"))
4857                 DIFF_OPT_CLR(options, FUNCCONTEXT);
4858         else if ((argcount = parse_long_opt("output", av, &optarg))) {
4859                 char *path = prefix_filename(prefix, optarg);
4860                 options->file = xfopen(path, "w");
4861                 options->close_file = 1;
4862                 if (options->use_color != GIT_COLOR_ALWAYS)
4863                         options->use_color = GIT_COLOR_NEVER;
4864                 free(path);
4865                 return argcount;
4866         } else
4867                 return 0;
4868         return 1;
4869 }
4870
4871 int parse_rename_score(const char **cp_p)
4872 {
4873         unsigned long num, scale;
4874         int ch, dot;
4875         const char *cp = *cp_p;
4876
4877         num = 0;
4878         scale = 1;
4879         dot = 0;
4880         for (;;) {
4881                 ch = *cp;
4882                 if ( !dot && ch == '.' ) {
4883                         scale = 1;
4884                         dot = 1;
4885                 } else if ( ch == '%' ) {
4886                         scale = dot ? scale*100 : 100;
4887                         cp++;   /* % is always at the end */
4888                         break;
4889                 } else if ( ch >= '0' && ch <= '9' ) {
4890                         if ( scale < 100000 ) {
4891                                 scale *= 10;
4892                                 num = (num*10) + (ch-'0');
4893                         }
4894                 } else {
4895                         break;
4896                 }
4897                 cp++;
4898         }
4899         *cp_p = cp;
4900
4901         /* user says num divided by scale and we say internally that
4902          * is MAX_SCORE * num / scale.
4903          */
4904         return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
4905 }
4906
4907 static int diff_scoreopt_parse(const char *opt)
4908 {
4909         int opt1, opt2, cmd;
4910
4911         if (*opt++ != '-')
4912                 return -1;
4913         cmd = *opt++;
4914         if (cmd == '-') {
4915                 /* convert the long-form arguments into short-form versions */
4916                 if (skip_prefix(opt, "break-rewrites", &opt)) {
4917                         if (*opt == 0 || *opt++ == '=')
4918                                 cmd = 'B';
4919                 } else if (skip_prefix(opt, "find-copies", &opt)) {
4920                         if (*opt == 0 || *opt++ == '=')
4921                                 cmd = 'C';
4922                 } else if (skip_prefix(opt, "find-renames", &opt)) {
4923                         if (*opt == 0 || *opt++ == '=')
4924                                 cmd = 'M';
4925                 }
4926         }
4927         if (cmd != 'M' && cmd != 'C' && cmd != 'B')
4928                 return -1; /* that is not a -M, -C, or -B option */
4929
4930         opt1 = parse_rename_score(&opt);
4931         if (cmd != 'B')
4932                 opt2 = 0;
4933         else {
4934                 if (*opt == 0)
4935                         opt2 = 0;
4936                 else if (*opt != '/')
4937                         return -1; /* we expect -B80/99 or -B80 */
4938                 else {
4939                         opt++;
4940                         opt2 = parse_rename_score(&opt);
4941                 }
4942         }
4943         if (*opt != 0)
4944                 return -1;
4945         return opt1 | (opt2 << 16);
4946 }
4947
4948 struct diff_queue_struct diff_queued_diff;
4949
4950 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
4951 {
4952         ALLOC_GROW(queue->queue, queue->nr + 1, queue->alloc);
4953         queue->queue[queue->nr++] = dp;
4954 }
4955
4956 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
4957                                  struct diff_filespec *one,
4958                                  struct diff_filespec *two)
4959 {
4960         struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
4961         dp->one = one;
4962         dp->two = two;
4963         if (queue)
4964                 diff_q(queue, dp);
4965         return dp;
4966 }
4967
4968 void diff_free_filepair(struct diff_filepair *p)
4969 {
4970         free_filespec(p->one);
4971         free_filespec(p->two);
4972         free(p);
4973 }
4974
4975 const char *diff_aligned_abbrev(const struct object_id *oid, int len)
4976 {
4977         int abblen;
4978         const char *abbrev;
4979
4980         if (len == GIT_SHA1_HEXSZ)
4981                 return oid_to_hex(oid);
4982
4983         abbrev = diff_abbrev_oid(oid, len);
4984         abblen = strlen(abbrev);
4985
4986         /*
4987          * In well-behaved cases, where the abbbreviated result is the
4988          * same as the requested length, append three dots after the
4989          * abbreviation (hence the whole logic is limited to the case
4990          * where abblen < 37); when the actual abbreviated result is a
4991          * bit longer than the requested length, we reduce the number
4992          * of dots so that they match the well-behaved ones.  However,
4993          * if the actual abbreviation is longer than the requested
4994          * length by more than three, we give up on aligning, and add
4995          * three dots anyway, to indicate that the output is not the
4996          * full object name.  Yes, this may be suboptimal, but this
4997          * appears only in "diff --raw --abbrev" output and it is not
4998          * worth the effort to change it now.  Note that this would
4999          * likely to work fine when the automatic sizing of default
5000          * abbreviation length is used--we would be fed -1 in "len" in
5001          * that case, and will end up always appending three-dots, but
5002          * the automatic sizing is supposed to give abblen that ensures
5003          * uniqueness across all objects (statistically speaking).
5004          */
5005         if (abblen < GIT_SHA1_HEXSZ - 3) {
5006                 static char hex[GIT_MAX_HEXSZ + 1];
5007                 if (len < abblen && abblen <= len + 2)
5008                         xsnprintf(hex, sizeof(hex), "%s%.*s", abbrev, len+3-abblen, "..");
5009                 else
5010                         xsnprintf(hex, sizeof(hex), "%s...", abbrev);
5011                 return hex;
5012         }
5013
5014         return oid_to_hex(oid);
5015 }
5016
5017 static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
5018 {
5019         int line_termination = opt->line_termination;
5020         int inter_name_termination = line_termination ? '\t' : '\0';
5021
5022         fprintf(opt->file, "%s", diff_line_prefix(opt));
5023         if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
5024                 fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
5025                         diff_aligned_abbrev(&p->one->oid, opt->abbrev));
5026                 fprintf(opt->file, "%s ",
5027                         diff_aligned_abbrev(&p->two->oid, opt->abbrev));
5028         }
5029         if (p->score) {
5030                 fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
5031                         inter_name_termination);
5032         } else {
5033                 fprintf(opt->file, "%c%c", p->status, inter_name_termination);
5034         }
5035
5036         if (p->status == DIFF_STATUS_COPIED ||
5037             p->status == DIFF_STATUS_RENAMED) {
5038                 const char *name_a, *name_b;
5039                 name_a = p->one->path;
5040                 name_b = p->two->path;
5041                 strip_prefix(opt->prefix_length, &name_a, &name_b);
5042                 write_name_quoted(name_a, opt->file, inter_name_termination);
5043                 write_name_quoted(name_b, opt->file, line_termination);
5044         } else {
5045                 const char *name_a, *name_b;
5046                 name_a = p->one->mode ? p->one->path : p->two->path;
5047                 name_b = NULL;
5048                 strip_prefix(opt->prefix_length, &name_a, &name_b);
5049                 write_name_quoted(name_a, opt->file, line_termination);
5050         }
5051 }
5052
5053 int diff_unmodified_pair(struct diff_filepair *p)
5054 {
5055         /* This function is written stricter than necessary to support
5056          * the currently implemented transformers, but the idea is to
5057          * let transformers to produce diff_filepairs any way they want,
5058          * and filter and clean them up here before producing the output.
5059          */
5060         struct diff_filespec *one = p->one, *two = p->two;
5061
5062         if (DIFF_PAIR_UNMERGED(p))
5063                 return 0; /* unmerged is interesting */
5064
5065         /* deletion, addition, mode or type change
5066          * and rename are all interesting.
5067          */
5068         if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
5069             DIFF_PAIR_MODE_CHANGED(p) ||
5070             strcmp(one->path, two->path))
5071                 return 0;
5072
5073         /* both are valid and point at the same path.  that is, we are
5074          * dealing with a change.
5075          */
5076         if (one->oid_valid && two->oid_valid &&
5077             !oidcmp(&one->oid, &two->oid) &&
5078             !one->dirty_submodule && !two->dirty_submodule)
5079                 return 1; /* no change */
5080         if (!one->oid_valid && !two->oid_valid)
5081                 return 1; /* both look at the same file on the filesystem. */
5082         return 0;
5083 }
5084
5085 static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
5086 {
5087         if (diff_unmodified_pair(p))
5088                 return;
5089
5090         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5091             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5092                 return; /* no tree diffs in patch format */
5093
5094         run_diff(p, o);
5095 }
5096
5097 static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
5098                             struct diffstat_t *diffstat)
5099 {
5100         if (diff_unmodified_pair(p))
5101                 return;
5102
5103         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5104             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5105                 return; /* no useful stat for tree diffs */
5106
5107         run_diffstat(p, o, diffstat);
5108 }
5109
5110 static void diff_flush_checkdiff(struct diff_filepair *p,
5111                 struct diff_options *o)
5112 {
5113         if (diff_unmodified_pair(p))
5114                 return;
5115
5116         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5117             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5118                 return; /* nothing to check in tree diffs */
5119
5120         run_checkdiff(p, o);
5121 }
5122
5123 int diff_queue_is_empty(void)
5124 {
5125         struct diff_queue_struct *q = &diff_queued_diff;
5126         int i;
5127         for (i = 0; i < q->nr; i++)
5128                 if (!diff_unmodified_pair(q->queue[i]))
5129                         return 0;
5130         return 1;
5131 }
5132
5133 #if DIFF_DEBUG
5134 void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
5135 {
5136         fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
5137                 x, one ? one : "",
5138                 s->path,
5139                 DIFF_FILE_VALID(s) ? "valid" : "invalid",
5140                 s->mode,
5141                 s->oid_valid ? oid_to_hex(&s->oid) : "");
5142         fprintf(stderr, "queue[%d] %s size %lu\n",
5143                 x, one ? one : "",
5144                 s->size);
5145 }
5146
5147 void diff_debug_filepair(const struct diff_filepair *p, int i)
5148 {
5149         diff_debug_filespec(p->one, i, "one");
5150         diff_debug_filespec(p->two, i, "two");
5151         fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
5152                 p->score, p->status ? p->status : '?',
5153                 p->one->rename_used, p->broken_pair);
5154 }
5155
5156 void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
5157 {
5158         int i;
5159         if (msg)
5160                 fprintf(stderr, "%s\n", msg);
5161         fprintf(stderr, "q->nr = %d\n", q->nr);
5162         for (i = 0; i < q->nr; i++) {
5163                 struct diff_filepair *p = q->queue[i];
5164                 diff_debug_filepair(p, i);
5165         }
5166 }
5167 #endif
5168
5169 static void diff_resolve_rename_copy(void)
5170 {
5171         int i;
5172         struct diff_filepair *p;
5173         struct diff_queue_struct *q = &diff_queued_diff;
5174
5175         diff_debug_queue("resolve-rename-copy", q);
5176
5177         for (i = 0; i < q->nr; i++) {
5178                 p = q->queue[i];
5179                 p->status = 0; /* undecided */
5180                 if (DIFF_PAIR_UNMERGED(p))
5181                         p->status = DIFF_STATUS_UNMERGED;
5182                 else if (!DIFF_FILE_VALID(p->one))
5183                         p->status = DIFF_STATUS_ADDED;
5184                 else if (!DIFF_FILE_VALID(p->two))
5185                         p->status = DIFF_STATUS_DELETED;
5186                 else if (DIFF_PAIR_TYPE_CHANGED(p))
5187                         p->status = DIFF_STATUS_TYPE_CHANGED;
5188
5189                 /* from this point on, we are dealing with a pair
5190                  * whose both sides are valid and of the same type, i.e.
5191                  * either in-place edit or rename/copy edit.
5192                  */
5193                 else if (DIFF_PAIR_RENAME(p)) {
5194                         /*
5195                          * A rename might have re-connected a broken
5196                          * pair up, causing the pathnames to be the
5197                          * same again. If so, that's not a rename at
5198                          * all, just a modification..
5199                          *
5200                          * Otherwise, see if this source was used for
5201                          * multiple renames, in which case we decrement
5202                          * the count, and call it a copy.
5203                          */
5204                         if (!strcmp(p->one->path, p->two->path))
5205                                 p->status = DIFF_STATUS_MODIFIED;
5206                         else if (--p->one->rename_used > 0)
5207                                 p->status = DIFF_STATUS_COPIED;
5208                         else
5209                                 p->status = DIFF_STATUS_RENAMED;
5210                 }
5211                 else if (oidcmp(&p->one->oid, &p->two->oid) ||
5212                          p->one->mode != p->two->mode ||
5213                          p->one->dirty_submodule ||
5214                          p->two->dirty_submodule ||
5215                          is_null_oid(&p->one->oid))
5216                         p->status = DIFF_STATUS_MODIFIED;
5217                 else {
5218                         /* This is a "no-change" entry and should not
5219                          * happen anymore, but prepare for broken callers.
5220                          */
5221                         error("feeding unmodified %s to diffcore",
5222                               p->one->path);
5223                         p->status = DIFF_STATUS_UNKNOWN;
5224                 }
5225         }
5226         diff_debug_queue("resolve-rename-copy done", q);
5227 }
5228
5229 static int check_pair_status(struct diff_filepair *p)
5230 {
5231         switch (p->status) {
5232         case DIFF_STATUS_UNKNOWN:
5233                 return 0;
5234         case 0:
5235                 die("internal error in diff-resolve-rename-copy");
5236         default:
5237                 return 1;
5238         }
5239 }
5240
5241 static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
5242 {
5243         int fmt = opt->output_format;
5244
5245         if (fmt & DIFF_FORMAT_CHECKDIFF)
5246                 diff_flush_checkdiff(p, opt);
5247         else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
5248                 diff_flush_raw(p, opt);
5249         else if (fmt & DIFF_FORMAT_NAME) {
5250                 const char *name_a, *name_b;
5251                 name_a = p->two->path;
5252                 name_b = NULL;
5253                 strip_prefix(opt->prefix_length, &name_a, &name_b);
5254                 fprintf(opt->file, "%s", diff_line_prefix(opt));
5255                 write_name_quoted(name_a, opt->file, opt->line_termination);
5256         }
5257 }
5258
5259 static void show_file_mode_name(struct diff_options *opt, const char *newdelete, struct diff_filespec *fs)
5260 {
5261         struct strbuf sb = STRBUF_INIT;
5262         if (fs->mode)
5263                 strbuf_addf(&sb, " %s mode %06o ", newdelete, fs->mode);
5264         else
5265                 strbuf_addf(&sb, " %s ", newdelete);
5266
5267         quote_c_style(fs->path, &sb, NULL, 0);
5268         strbuf_addch(&sb, '\n');
5269         emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5270                          sb.buf, sb.len, 0);
5271         strbuf_release(&sb);
5272 }
5273
5274 static void show_mode_change(struct diff_options *opt, struct diff_filepair *p,
5275                 int show_name)
5276 {
5277         if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
5278                 struct strbuf sb = STRBUF_INIT;
5279                 strbuf_addf(&sb, " mode change %06o => %06o",
5280                             p->one->mode, p->two->mode);
5281                 if (show_name) {
5282                         strbuf_addch(&sb, ' ');
5283                         quote_c_style(p->two->path, &sb, NULL, 0);
5284                 }
5285                 emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5286                                  sb.buf, sb.len, 0);
5287                 strbuf_release(&sb);
5288         }
5289 }
5290
5291 static void show_rename_copy(struct diff_options *opt, const char *renamecopy,
5292                 struct diff_filepair *p)
5293 {
5294         struct strbuf sb = STRBUF_INIT;
5295         char *names = pprint_rename(p->one->path, p->two->path);
5296         strbuf_addf(&sb, " %s %s (%d%%)\n",
5297                         renamecopy, names, similarity_index(p));
5298         free(names);
5299         emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5300                                  sb.buf, sb.len, 0);
5301         show_mode_change(opt, p, 0);
5302 }
5303
5304 static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
5305 {
5306         switch(p->status) {
5307         case DIFF_STATUS_DELETED:
5308                 show_file_mode_name(opt, "delete", p->one);
5309                 break;
5310         case DIFF_STATUS_ADDED:
5311                 show_file_mode_name(opt, "create", p->two);
5312                 break;
5313         case DIFF_STATUS_COPIED:
5314                 show_rename_copy(opt, "copy", p);
5315                 break;
5316         case DIFF_STATUS_RENAMED:
5317                 show_rename_copy(opt, "rename", p);
5318                 break;
5319         default:
5320                 if (p->score) {
5321                         struct strbuf sb = STRBUF_INIT;
5322                         strbuf_addstr(&sb, " rewrite ");
5323                         quote_c_style(p->two->path, &sb, NULL, 0);
5324                         strbuf_addf(&sb, " (%d%%)\n", similarity_index(p));
5325                         emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5326                                          sb.buf, sb.len, 0);
5327                 }
5328                 show_mode_change(opt, p, !p->score);
5329                 break;
5330         }
5331 }
5332
5333 struct patch_id_t {
5334         git_SHA_CTX *ctx;
5335         int patchlen;
5336 };
5337
5338 static int remove_space(char *line, int len)
5339 {
5340         int i;
5341         char *dst = line;
5342         unsigned char c;
5343
5344         for (i = 0; i < len; i++)
5345                 if (!isspace((c = line[i])))
5346                         *dst++ = c;
5347
5348         return dst - line;
5349 }
5350
5351 static void patch_id_consume(void *priv, char *line, unsigned long len)
5352 {
5353         struct patch_id_t *data = priv;
5354         int new_len;
5355
5356         /* Ignore line numbers when computing the SHA1 of the patch */
5357         if (starts_with(line, "@@ -"))
5358                 return;
5359
5360         new_len = remove_space(line, len);
5361
5362         git_SHA1_Update(data->ctx, line, new_len);
5363         data->patchlen += new_len;
5364 }
5365
5366 static void patch_id_add_string(git_SHA_CTX *ctx, const char *str)
5367 {
5368         git_SHA1_Update(ctx, str, strlen(str));
5369 }
5370
5371 static void patch_id_add_mode(git_SHA_CTX *ctx, unsigned mode)
5372 {
5373         /* large enough for 2^32 in octal */
5374         char buf[12];
5375         int len = xsnprintf(buf, sizeof(buf), "%06o", mode);
5376         git_SHA1_Update(ctx, buf, len);
5377 }
5378
5379 /* returns 0 upon success, and writes result into sha1 */
5380 static int diff_get_patch_id(struct diff_options *options, struct object_id *oid, int diff_header_only)
5381 {
5382         struct diff_queue_struct *q = &diff_queued_diff;
5383         int i;
5384         git_SHA_CTX ctx;
5385         struct patch_id_t data;
5386
5387         git_SHA1_Init(&ctx);
5388         memset(&data, 0, sizeof(struct patch_id_t));
5389         data.ctx = &ctx;
5390
5391         for (i = 0; i < q->nr; i++) {
5392                 xpparam_t xpp;
5393                 xdemitconf_t xecfg;
5394                 mmfile_t mf1, mf2;
5395                 struct diff_filepair *p = q->queue[i];
5396                 int len1, len2;
5397
5398                 memset(&xpp, 0, sizeof(xpp));
5399                 memset(&xecfg, 0, sizeof(xecfg));
5400                 if (p->status == 0)
5401                         return error("internal diff status error");
5402                 if (p->status == DIFF_STATUS_UNKNOWN)
5403                         continue;
5404                 if (diff_unmodified_pair(p))
5405                         continue;
5406                 if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5407                     (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5408                         continue;
5409                 if (DIFF_PAIR_UNMERGED(p))
5410                         continue;
5411
5412                 diff_fill_oid_info(p->one);
5413                 diff_fill_oid_info(p->two);
5414
5415                 len1 = remove_space(p->one->path, strlen(p->one->path));
5416                 len2 = remove_space(p->two->path, strlen(p->two->path));
5417                 patch_id_add_string(&ctx, "diff--git");
5418                 patch_id_add_string(&ctx, "a/");
5419                 git_SHA1_Update(&ctx, p->one->path, len1);
5420                 patch_id_add_string(&ctx, "b/");
5421                 git_SHA1_Update(&ctx, p->two->path, len2);
5422
5423                 if (p->one->mode == 0) {
5424                         patch_id_add_string(&ctx, "newfilemode");
5425                         patch_id_add_mode(&ctx, p->two->mode);
5426                         patch_id_add_string(&ctx, "---/dev/null");
5427                         patch_id_add_string(&ctx, "+++b/");
5428                         git_SHA1_Update(&ctx, p->two->path, len2);
5429                 } else if (p->two->mode == 0) {
5430                         patch_id_add_string(&ctx, "deletedfilemode");
5431                         patch_id_add_mode(&ctx, p->one->mode);
5432                         patch_id_add_string(&ctx, "---a/");
5433                         git_SHA1_Update(&ctx, p->one->path, len1);
5434                         patch_id_add_string(&ctx, "+++/dev/null");
5435                 } else {
5436                         patch_id_add_string(&ctx, "---a/");
5437                         git_SHA1_Update(&ctx, p->one->path, len1);
5438                         patch_id_add_string(&ctx, "+++b/");
5439                         git_SHA1_Update(&ctx, p->two->path, len2);
5440                 }
5441
5442                 if (diff_header_only)
5443                         continue;
5444
5445                 if (fill_mmfile(&mf1, p->one) < 0 ||
5446                     fill_mmfile(&mf2, p->two) < 0)
5447                         return error("unable to read files to diff");
5448
5449                 if (diff_filespec_is_binary(p->one) ||
5450                     diff_filespec_is_binary(p->two)) {
5451                         git_SHA1_Update(&ctx, oid_to_hex(&p->one->oid),
5452                                         GIT_SHA1_HEXSZ);
5453                         git_SHA1_Update(&ctx, oid_to_hex(&p->two->oid),
5454                                         GIT_SHA1_HEXSZ);
5455                         continue;
5456                 }
5457
5458                 xpp.flags = 0;
5459                 xecfg.ctxlen = 3;
5460                 xecfg.flags = 0;
5461                 if (xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
5462                                   &xpp, &xecfg))
5463                         return error("unable to generate patch-id diff for %s",
5464                                      p->one->path);
5465         }
5466
5467         git_SHA1_Final(oid->hash, &ctx);
5468         return 0;
5469 }
5470
5471 int diff_flush_patch_id(struct diff_options *options, struct object_id *oid, int diff_header_only)
5472 {
5473         struct diff_queue_struct *q = &diff_queued_diff;
5474         int i;
5475         int result = diff_get_patch_id(options, oid, diff_header_only);
5476
5477         for (i = 0; i < q->nr; i++)
5478                 diff_free_filepair(q->queue[i]);
5479
5480         free(q->queue);
5481         DIFF_QUEUE_CLEAR(q);
5482
5483         return result;
5484 }
5485
5486 static int is_summary_empty(const struct diff_queue_struct *q)
5487 {
5488         int i;
5489
5490         for (i = 0; i < q->nr; i++) {
5491                 const struct diff_filepair *p = q->queue[i];
5492
5493                 switch (p->status) {
5494                 case DIFF_STATUS_DELETED:
5495                 case DIFF_STATUS_ADDED:
5496                 case DIFF_STATUS_COPIED:
5497                 case DIFF_STATUS_RENAMED:
5498                         return 0;
5499                 default:
5500                         if (p->score)
5501                                 return 0;
5502                         if (p->one->mode && p->two->mode &&
5503                             p->one->mode != p->two->mode)
5504                                 return 0;
5505                         break;
5506                 }
5507         }
5508         return 1;
5509 }
5510
5511 static const char rename_limit_warning[] =
5512 N_("inexact rename detection was skipped due to too many files.");
5513
5514 static const char degrade_cc_to_c_warning[] =
5515 N_("only found copies from modified paths due to too many files.");
5516
5517 static const char rename_limit_advice[] =
5518 N_("you may want to set your %s variable to at least "
5519    "%d and retry the command.");
5520
5521 void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
5522 {
5523         if (degraded_cc)
5524                 warning(_(degrade_cc_to_c_warning));
5525         else if (needed)
5526                 warning(_(rename_limit_warning));
5527         else
5528                 return;
5529         if (0 < needed && needed < 32767)
5530                 warning(_(rename_limit_advice), varname, needed);
5531 }
5532
5533 static void diff_flush_patch_all_file_pairs(struct diff_options *o)
5534 {
5535         int i;
5536         static struct emitted_diff_symbols esm = EMITTED_DIFF_SYMBOLS_INIT;
5537         struct diff_queue_struct *q = &diff_queued_diff;
5538
5539         if (WSEH_NEW & WS_RULE_MASK)
5540                 die("BUG: WS rules bit mask overlaps with diff symbol flags");
5541
5542         if (o->color_moved)
5543                 o->emitted_symbols = &esm;
5544
5545         for (i = 0; i < q->nr; i++) {
5546                 struct diff_filepair *p = q->queue[i];
5547                 if (check_pair_status(p))
5548                         diff_flush_patch(p, o);
5549         }
5550
5551         if (o->emitted_symbols) {
5552                 if (o->color_moved) {
5553                         struct hashmap add_lines, del_lines;
5554
5555                         hashmap_init(&del_lines,
5556                                      (hashmap_cmp_fn)moved_entry_cmp, o, 0);
5557                         hashmap_init(&add_lines,
5558                                      (hashmap_cmp_fn)moved_entry_cmp, o, 0);
5559
5560                         add_lines_to_move_detection(o, &add_lines, &del_lines);
5561                         mark_color_as_moved(o, &add_lines, &del_lines);
5562                         if (o->color_moved == COLOR_MOVED_ZEBRA_DIM)
5563                                 dim_moved_lines(o);
5564
5565                         hashmap_free(&add_lines, 0);
5566                         hashmap_free(&del_lines, 0);
5567                 }
5568
5569                 for (i = 0; i < esm.nr; i++)
5570                         emit_diff_symbol_from_struct(o, &esm.buf[i]);
5571
5572                 for (i = 0; i < esm.nr; i++)
5573                         free((void *)esm.buf[i].line);
5574         }
5575         esm.nr = 0;
5576 }
5577
5578 void diff_flush(struct diff_options *options)
5579 {
5580         struct diff_queue_struct *q = &diff_queued_diff;
5581         int i, output_format = options->output_format;
5582         int separator = 0;
5583         int dirstat_by_line = 0;
5584
5585         /*
5586          * Order: raw, stat, summary, patch
5587          * or:    name/name-status/checkdiff (other bits clear)
5588          */
5589         if (!q->nr)
5590                 goto free_queue;
5591
5592         if (output_format & (DIFF_FORMAT_RAW |
5593                              DIFF_FORMAT_NAME |
5594                              DIFF_FORMAT_NAME_STATUS |
5595                              DIFF_FORMAT_CHECKDIFF)) {
5596                 for (i = 0; i < q->nr; i++) {
5597                         struct diff_filepair *p = q->queue[i];
5598                         if (check_pair_status(p))
5599                                 flush_one_pair(p, options);
5600                 }
5601                 separator++;
5602         }
5603
5604         if (output_format & DIFF_FORMAT_DIRSTAT && DIFF_OPT_TST(options, DIRSTAT_BY_LINE))
5605                 dirstat_by_line = 1;
5606
5607         if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
5608             dirstat_by_line) {
5609                 struct diffstat_t diffstat;
5610
5611                 memset(&diffstat, 0, sizeof(struct diffstat_t));
5612                 for (i = 0; i < q->nr; i++) {
5613                         struct diff_filepair *p = q->queue[i];
5614                         if (check_pair_status(p))
5615                                 diff_flush_stat(p, options, &diffstat);
5616                 }
5617                 if (output_format & DIFF_FORMAT_NUMSTAT)
5618                         show_numstat(&diffstat, options);
5619                 if (output_format & DIFF_FORMAT_DIFFSTAT)
5620                         show_stats(&diffstat, options);
5621                 if (output_format & DIFF_FORMAT_SHORTSTAT)
5622                         show_shortstats(&diffstat, options);
5623                 if (output_format & DIFF_FORMAT_DIRSTAT && dirstat_by_line)
5624                         show_dirstat_by_line(&diffstat, options);
5625                 free_diffstat_info(&diffstat);
5626                 separator++;
5627         }
5628         if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
5629                 show_dirstat(options);
5630
5631         if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
5632                 for (i = 0; i < q->nr; i++) {
5633                         diff_summary(options, q->queue[i]);
5634                 }
5635                 separator++;
5636         }
5637
5638         if (output_format & DIFF_FORMAT_NO_OUTPUT &&
5639             DIFF_OPT_TST(options, EXIT_WITH_STATUS) &&
5640             DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
5641                 /*
5642                  * run diff_flush_patch for the exit status. setting
5643                  * options->file to /dev/null should be safe, because we
5644                  * aren't supposed to produce any output anyway.
5645                  */
5646                 if (options->close_file)
5647                         fclose(options->file);
5648                 options->file = xfopen("/dev/null", "w");
5649                 options->close_file = 1;
5650                 options->color_moved = 0;
5651                 for (i = 0; i < q->nr; i++) {
5652                         struct diff_filepair *p = q->queue[i];
5653                         if (check_pair_status(p))
5654                                 diff_flush_patch(p, options);
5655                         if (options->found_changes)
5656                                 break;
5657                 }
5658         }
5659
5660         if (output_format & DIFF_FORMAT_PATCH) {
5661                 if (separator) {
5662                         emit_diff_symbol(options, DIFF_SYMBOL_SEPARATOR, NULL, 0, 0);
5663                         if (options->stat_sep)
5664                                 /* attach patch instead of inline */
5665                                 emit_diff_symbol(options, DIFF_SYMBOL_STAT_SEP,
5666                                                  NULL, 0, 0);
5667                 }
5668
5669                 diff_flush_patch_all_file_pairs(options);
5670         }
5671
5672         if (output_format & DIFF_FORMAT_CALLBACK)
5673                 options->format_callback(q, options, options->format_callback_data);
5674
5675         for (i = 0; i < q->nr; i++)
5676                 diff_free_filepair(q->queue[i]);
5677 free_queue:
5678         free(q->queue);
5679         DIFF_QUEUE_CLEAR(q);
5680         if (options->close_file)
5681                 fclose(options->file);
5682
5683         /*
5684          * Report the content-level differences with HAS_CHANGES;
5685          * diff_addremove/diff_change does not set the bit when
5686          * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
5687          */
5688         if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
5689                 if (options->found_changes)
5690                         DIFF_OPT_SET(options, HAS_CHANGES);
5691                 else
5692                         DIFF_OPT_CLR(options, HAS_CHANGES);
5693         }
5694 }
5695
5696 static int match_filter(const struct diff_options *options, const struct diff_filepair *p)
5697 {
5698         return (((p->status == DIFF_STATUS_MODIFIED) &&
5699                  ((p->score &&
5700                    filter_bit_tst(DIFF_STATUS_FILTER_BROKEN, options)) ||
5701                   (!p->score &&
5702                    filter_bit_tst(DIFF_STATUS_MODIFIED, options)))) ||
5703                 ((p->status != DIFF_STATUS_MODIFIED) &&
5704                  filter_bit_tst(p->status, options)));
5705 }
5706
5707 static void diffcore_apply_filter(struct diff_options *options)
5708 {
5709         int i;
5710         struct diff_queue_struct *q = &diff_queued_diff;
5711         struct diff_queue_struct outq;
5712
5713         DIFF_QUEUE_CLEAR(&outq);
5714
5715         if (!options->filter)
5716                 return;
5717
5718         if (filter_bit_tst(DIFF_STATUS_FILTER_AON, options)) {
5719                 int found;
5720                 for (i = found = 0; !found && i < q->nr; i++) {
5721                         if (match_filter(options, q->queue[i]))
5722                                 found++;
5723                 }
5724                 if (found)
5725                         return;
5726
5727                 /* otherwise we will clear the whole queue
5728                  * by copying the empty outq at the end of this
5729                  * function, but first clear the current entries
5730                  * in the queue.
5731                  */
5732                 for (i = 0; i < q->nr; i++)
5733                         diff_free_filepair(q->queue[i]);
5734         }
5735         else {
5736                 /* Only the matching ones */
5737                 for (i = 0; i < q->nr; i++) {
5738                         struct diff_filepair *p = q->queue[i];
5739                         if (match_filter(options, p))
5740                                 diff_q(&outq, p);
5741                         else
5742                                 diff_free_filepair(p);
5743                 }
5744         }
5745         free(q->queue);
5746         *q = outq;
5747 }
5748
5749 /* Check whether two filespecs with the same mode and size are identical */
5750 static int diff_filespec_is_identical(struct diff_filespec *one,
5751                                       struct diff_filespec *two)
5752 {
5753         if (S_ISGITLINK(one->mode))
5754                 return 0;
5755         if (diff_populate_filespec(one, 0))
5756                 return 0;
5757         if (diff_populate_filespec(two, 0))
5758                 return 0;
5759         return !memcmp(one->data, two->data, one->size);
5760 }
5761
5762 static int diff_filespec_check_stat_unmatch(struct diff_filepair *p)
5763 {
5764         if (p->done_skip_stat_unmatch)
5765                 return p->skip_stat_unmatch_result;
5766
5767         p->done_skip_stat_unmatch = 1;
5768         p->skip_stat_unmatch_result = 0;
5769         /*
5770          * 1. Entries that come from stat info dirtiness
5771          *    always have both sides (iow, not create/delete),
5772          *    one side of the object name is unknown, with
5773          *    the same mode and size.  Keep the ones that
5774          *    do not match these criteria.  They have real
5775          *    differences.
5776          *
5777          * 2. At this point, the file is known to be modified,
5778          *    with the same mode and size, and the object
5779          *    name of one side is unknown.  Need to inspect
5780          *    the identical contents.
5781          */
5782         if (!DIFF_FILE_VALID(p->one) || /* (1) */
5783             !DIFF_FILE_VALID(p->two) ||
5784             (p->one->oid_valid && p->two->oid_valid) ||
5785             (p->one->mode != p->two->mode) ||
5786             diff_populate_filespec(p->one, CHECK_SIZE_ONLY) ||
5787             diff_populate_filespec(p->two, CHECK_SIZE_ONLY) ||
5788             (p->one->size != p->two->size) ||
5789             !diff_filespec_is_identical(p->one, p->two)) /* (2) */
5790                 p->skip_stat_unmatch_result = 1;
5791         return p->skip_stat_unmatch_result;
5792 }
5793
5794 static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
5795 {
5796         int i;
5797         struct diff_queue_struct *q = &diff_queued_diff;
5798         struct diff_queue_struct outq;
5799         DIFF_QUEUE_CLEAR(&outq);
5800
5801         for (i = 0; i < q->nr; i++) {
5802                 struct diff_filepair *p = q->queue[i];
5803
5804                 if (diff_filespec_check_stat_unmatch(p))
5805                         diff_q(&outq, p);
5806                 else {
5807                         /*
5808                          * The caller can subtract 1 from skip_stat_unmatch
5809                          * to determine how many paths were dirty only
5810                          * due to stat info mismatch.
5811                          */
5812                         if (!DIFF_OPT_TST(diffopt, NO_INDEX))
5813                                 diffopt->skip_stat_unmatch++;
5814                         diff_free_filepair(p);
5815                 }
5816         }
5817         free(q->queue);
5818         *q = outq;
5819 }
5820
5821 static int diffnamecmp(const void *a_, const void *b_)
5822 {
5823         const struct diff_filepair *a = *((const struct diff_filepair **)a_);
5824         const struct diff_filepair *b = *((const struct diff_filepair **)b_);
5825         const char *name_a, *name_b;
5826
5827         name_a = a->one ? a->one->path : a->two->path;
5828         name_b = b->one ? b->one->path : b->two->path;
5829         return strcmp(name_a, name_b);
5830 }
5831
5832 void diffcore_fix_diff_index(struct diff_options *options)
5833 {
5834         struct diff_queue_struct *q = &diff_queued_diff;
5835         QSORT(q->queue, q->nr, diffnamecmp);
5836 }
5837
5838 void diffcore_std(struct diff_options *options)
5839 {
5840         /* NOTE please keep the following in sync with diff_tree_combined() */
5841         if (options->skip_stat_unmatch)
5842                 diffcore_skip_stat_unmatch(options);
5843         if (!options->found_follow) {
5844                 /* See try_to_follow_renames() in tree-diff.c */
5845                 if (options->break_opt != -1)
5846                         diffcore_break(options->break_opt);
5847                 if (options->detect_rename)
5848                         diffcore_rename(options);
5849                 if (options->break_opt != -1)
5850                         diffcore_merge_broken();
5851         }
5852         if (options->pickaxe)
5853                 diffcore_pickaxe(options);
5854         if (options->orderfile)
5855                 diffcore_order(options->orderfile);
5856         if (!options->found_follow)
5857                 /* See try_to_follow_renames() in tree-diff.c */
5858                 diff_resolve_rename_copy();
5859         diffcore_apply_filter(options);
5860
5861         if (diff_queued_diff.nr && !DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
5862                 DIFF_OPT_SET(options, HAS_CHANGES);
5863         else
5864                 DIFF_OPT_CLR(options, HAS_CHANGES);
5865
5866         options->found_follow = 0;
5867 }
5868
5869 int diff_result_code(struct diff_options *opt, int status)
5870 {
5871         int result = 0;
5872
5873         diff_warn_rename_limit("diff.renameLimit",
5874                                opt->needed_rename_limit,
5875                                opt->degraded_cc_to_c);
5876         if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
5877             !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
5878                 return status;
5879         if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
5880             DIFF_OPT_TST(opt, HAS_CHANGES))
5881                 result |= 01;
5882         if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
5883             DIFF_OPT_TST(opt, CHECK_FAILED))
5884                 result |= 02;
5885         return result;
5886 }
5887
5888 int diff_can_quit_early(struct diff_options *opt)
5889 {
5890         return (DIFF_OPT_TST(opt, QUICK) &&
5891                 !opt->filter &&
5892                 DIFF_OPT_TST(opt, HAS_CHANGES));
5893 }
5894
5895 /*
5896  * Shall changes to this submodule be ignored?
5897  *
5898  * Submodule changes can be configured to be ignored separately for each path,
5899  * but that configuration can be overridden from the command line.
5900  */
5901 static int is_submodule_ignored(const char *path, struct diff_options *options)
5902 {
5903         int ignored = 0;
5904         unsigned orig_flags = options->flags;
5905         if (!DIFF_OPT_TST(options, OVERRIDE_SUBMODULE_CONFIG))
5906                 set_diffopt_flags_from_submodule_config(options, path);
5907         if (DIFF_OPT_TST(options, IGNORE_SUBMODULES))
5908                 ignored = 1;
5909         options->flags = orig_flags;
5910         return ignored;
5911 }
5912
5913 void diff_addremove(struct diff_options *options,
5914                     int addremove, unsigned mode,
5915                     const struct object_id *oid,
5916                     int oid_valid,
5917                     const char *concatpath, unsigned dirty_submodule)
5918 {
5919         struct diff_filespec *one, *two;
5920
5921         if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
5922                 return;
5923
5924         /* This may look odd, but it is a preparation for
5925          * feeding "there are unchanged files which should
5926          * not produce diffs, but when you are doing copy
5927          * detection you would need them, so here they are"
5928          * entries to the diff-core.  They will be prefixed
5929          * with something like '=' or '*' (I haven't decided
5930          * which but should not make any difference).
5931          * Feeding the same new and old to diff_change()
5932          * also has the same effect.
5933          * Before the final output happens, they are pruned after
5934          * merged into rename/copy pairs as appropriate.
5935          */
5936         if (DIFF_OPT_TST(options, REVERSE_DIFF))
5937                 addremove = (addremove == '+' ? '-' :
5938                              addremove == '-' ? '+' : addremove);
5939
5940         if (options->prefix &&
5941             strncmp(concatpath, options->prefix, options->prefix_length))
5942                 return;
5943
5944         one = alloc_filespec(concatpath);
5945         two = alloc_filespec(concatpath);
5946
5947         if (addremove != '+')
5948                 fill_filespec(one, oid, oid_valid, mode);
5949         if (addremove != '-') {
5950                 fill_filespec(two, oid, oid_valid, mode);
5951                 two->dirty_submodule = dirty_submodule;
5952         }
5953
5954         diff_queue(&diff_queued_diff, one, two);
5955         if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
5956                 DIFF_OPT_SET(options, HAS_CHANGES);
5957 }
5958
5959 void diff_change(struct diff_options *options,
5960                  unsigned old_mode, unsigned new_mode,
5961                  const struct object_id *old_oid,
5962                  const struct object_id *new_oid,
5963                  int old_oid_valid, int new_oid_valid,
5964                  const char *concatpath,
5965                  unsigned old_dirty_submodule, unsigned new_dirty_submodule)
5966 {
5967         struct diff_filespec *one, *two;
5968         struct diff_filepair *p;
5969
5970         if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
5971             is_submodule_ignored(concatpath, options))
5972                 return;
5973
5974         if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
5975                 SWAP(old_mode, new_mode);
5976                 SWAP(old_oid, new_oid);
5977                 SWAP(old_oid_valid, new_oid_valid);
5978                 SWAP(old_dirty_submodule, new_dirty_submodule);
5979         }
5980
5981         if (options->prefix &&
5982             strncmp(concatpath, options->prefix, options->prefix_length))
5983                 return;
5984
5985         one = alloc_filespec(concatpath);
5986         two = alloc_filespec(concatpath);
5987         fill_filespec(one, old_oid, old_oid_valid, old_mode);
5988         fill_filespec(two, new_oid, new_oid_valid, new_mode);
5989         one->dirty_submodule = old_dirty_submodule;
5990         two->dirty_submodule = new_dirty_submodule;
5991         p = diff_queue(&diff_queued_diff, one, two);
5992
5993         if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
5994                 return;
5995
5996         if (DIFF_OPT_TST(options, QUICK) && options->skip_stat_unmatch &&
5997             !diff_filespec_check_stat_unmatch(p))
5998                 return;
5999
6000         DIFF_OPT_SET(options, HAS_CHANGES);
6001 }
6002
6003 struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
6004 {
6005         struct diff_filepair *pair;
6006         struct diff_filespec *one, *two;
6007
6008         if (options->prefix &&
6009             strncmp(path, options->prefix, options->prefix_length))
6010                 return NULL;
6011
6012         one = alloc_filespec(path);
6013         two = alloc_filespec(path);
6014         pair = diff_queue(&diff_queued_diff, one, two);
6015         pair->is_unmerged = 1;
6016         return pair;
6017 }
6018
6019 static char *run_textconv(const char *pgm, struct diff_filespec *spec,
6020                 size_t *outsize)
6021 {
6022         struct diff_tempfile *temp;
6023         const char *argv[3];
6024         const char **arg = argv;
6025         struct child_process child = CHILD_PROCESS_INIT;
6026         struct strbuf buf = STRBUF_INIT;
6027         int err = 0;
6028
6029         temp = prepare_temp_file(spec->path, spec);
6030         *arg++ = pgm;
6031         *arg++ = temp->name;
6032         *arg = NULL;
6033
6034         child.use_shell = 1;
6035         child.argv = argv;
6036         child.out = -1;
6037         if (start_command(&child)) {
6038                 remove_tempfile();
6039                 return NULL;
6040         }
6041
6042         if (strbuf_read(&buf, child.out, 0) < 0)
6043                 err = error("error reading from textconv command '%s'", pgm);
6044         close(child.out);
6045
6046         if (finish_command(&child) || err) {
6047                 strbuf_release(&buf);
6048                 remove_tempfile();
6049                 return NULL;
6050         }
6051         remove_tempfile();
6052
6053         return strbuf_detach(&buf, outsize);
6054 }
6055
6056 size_t fill_textconv(struct userdiff_driver *driver,
6057                      struct diff_filespec *df,
6058                      char **outbuf)
6059 {
6060         size_t size;
6061
6062         if (!driver) {
6063                 if (!DIFF_FILE_VALID(df)) {
6064                         *outbuf = "";
6065                         return 0;
6066                 }
6067                 if (diff_populate_filespec(df, 0))
6068                         die("unable to read files to diff");
6069                 *outbuf = df->data;
6070                 return df->size;
6071         }
6072
6073         if (!driver->textconv)
6074                 die("BUG: fill_textconv called with non-textconv driver");
6075
6076         if (driver->textconv_cache && df->oid_valid) {
6077                 *outbuf = notes_cache_get(driver->textconv_cache,
6078                                           &df->oid,
6079                                           &size);
6080                 if (*outbuf)
6081                         return size;
6082         }
6083
6084         *outbuf = run_textconv(driver->textconv, df, &size);
6085         if (!*outbuf)
6086                 die("unable to read files to diff");
6087
6088         if (driver->textconv_cache && df->oid_valid) {
6089                 /* ignore errors, as we might be in a readonly repository */
6090                 notes_cache_put(driver->textconv_cache, &df->oid, *outbuf,
6091                                 size);
6092                 /*
6093                  * we could save up changes and flush them all at the end,
6094                  * but we would need an extra call after all diffing is done.
6095                  * Since generating a cache entry is the slow path anyway,
6096                  * this extra overhead probably isn't a big deal.
6097                  */
6098                 notes_cache_write(driver->textconv_cache);
6099         }
6100
6101         return size;
6102 }
6103
6104 int textconv_object(const char *path,
6105                     unsigned mode,
6106                     const struct object_id *oid,
6107                     int oid_valid,
6108                     char **buf,
6109                     unsigned long *buf_size)
6110 {
6111         struct diff_filespec *df;
6112         struct userdiff_driver *textconv;
6113
6114         df = alloc_filespec(path);
6115         fill_filespec(df, oid, oid_valid, mode);
6116         textconv = get_textconv(df);
6117         if (!textconv) {
6118                 free_filespec(df);
6119                 return 0;
6120         }
6121
6122         *buf_size = fill_textconv(textconv, df, buf);
6123         free_filespec(df);
6124         return 1;
6125 }
6126
6127 void setup_diff_pager(struct diff_options *opt)
6128 {
6129         /*
6130          * If the user asked for our exit code, then either they want --quiet
6131          * or --exit-code. We should definitely not bother with a pager in the
6132          * former case, as we will generate no output. Since we still properly
6133          * report our exit code even when a pager is run, we _could_ run a
6134          * pager with --exit-code. But since we have not done so historically,
6135          * and because it is easy to find people oneline advising "git diff
6136          * --exit-code" in hooks and other scripts, we do not do so.
6137          */
6138         if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
6139             check_pager_config("diff") != 0)
6140                 setup_pager();
6141 }