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