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 "object-store.h"
  17 #include "userdiff.h"
  18 #include "submodule-config.h"
  19 #include "submodule.h"
  20 #include "hashmap.h"
  21 #include "ll-merge.h"
  22 #include "string-list.h"
  23 #include "argv-array.h"
  24 #include "graph.h"
  25 #include "packfile.h"
  26 #include "help.h"
  27
  28 #ifdef NO_FAST_WORKING_DIRECTORY
  29 #define FAST_WORKING_DIRECTORY 0
  30 #else
  31 #define FAST_WORKING_DIRECTORY 1
  32 #endif
  33
  34 static int diff_detect_rename_default;
  35 static int diff_indent_heuristic = 1;
  36 static int diff_rename_limit_default = 400;
  37 static int diff_suppress_blank_empty;
  38 static int diff_use_color_default = -1;
  39 static int diff_color_moved_default;
  40 static int diff_color_moved_ws_default;
  41 static int diff_context_default = 3;
  42 static int diff_interhunk_context_default;
  43 static const char *diff_word_regex_cfg;
  44 static const char *external_diff_cmd_cfg;
  45 static const char *diff_order_file_cfg;
  46 int diff_auto_refresh_index = 1;
  47 static int diff_mnemonic_prefix;
  48 static int diff_no_prefix;
  49 static int diff_stat_graph_width;
  50 static int diff_dirstat_permille_default = 30;
  51 static struct diff_options default_diff_options;
  52 static long diff_algorithm;
  53 static unsigned ws_error_highlight_default = WSEH_NEW;
  54
  55 static char diff_colors[][COLOR_MAXLEN] = {
  56         GIT_COLOR_RESET,
  57         GIT_COLOR_NORMAL,       /* CONTEXT */
  58         GIT_COLOR_BOLD,         /* METAINFO */
  59         GIT_COLOR_CYAN,         /* FRAGINFO */
  60         GIT_COLOR_RED,          /* OLD */
  61         GIT_COLOR_GREEN,        /* NEW */
  62         GIT_COLOR_YELLOW,       /* COMMIT */
  63         GIT_COLOR_BG_RED,       /* WHITESPACE */
  64         GIT_COLOR_NORMAL,       /* FUNCINFO */
  65         GIT_COLOR_BOLD_MAGENTA, /* OLD_MOVED */
  66         GIT_COLOR_BOLD_BLUE,    /* OLD_MOVED ALTERNATIVE */
  67         GIT_COLOR_FAINT,        /* OLD_MOVED_DIM */
  68         GIT_COLOR_FAINT_ITALIC, /* OLD_MOVED_ALTERNATIVE_DIM */
  69         GIT_COLOR_BOLD_CYAN,    /* NEW_MOVED */
  70         GIT_COLOR_BOLD_YELLOW,  /* NEW_MOVED ALTERNATIVE */
  71         GIT_COLOR_FAINT,        /* NEW_MOVED_DIM */
  72         GIT_COLOR_FAINT_ITALIC, /* NEW_MOVED_ALTERNATIVE_DIM */
  73 };
  74
  75 static const char *color_diff_slots[] = {
  76         [DIFF_CONTEXT]                = "context",
  77         [DIFF_METAINFO]               = "meta",
  78         [DIFF_FRAGINFO]               = "frag",
  79         [DIFF_FILE_OLD]               = "old",
  80         [DIFF_FILE_NEW]               = "new",
  81         [DIFF_COMMIT]                 = "commit",
  82         [DIFF_WHITESPACE]             = "whitespace",
  83         [DIFF_FUNCINFO]               = "func",
  84         [DIFF_FILE_OLD_MOVED]         = "oldMoved",
  85         [DIFF_FILE_OLD_MOVED_ALT]     = "oldMovedAlternative",
  86         [DIFF_FILE_OLD_MOVED_DIM]     = "oldMovedDimmed",
  87         [DIFF_FILE_OLD_MOVED_ALT_DIM] = "oldMovedAlternativeDimmed",
  88         [DIFF_FILE_NEW_MOVED]         = "newMoved",
  89         [DIFF_FILE_NEW_MOVED_ALT]     = "newMovedAlternative",
  90         [DIFF_FILE_NEW_MOVED_DIM]     = "newMovedDimmed",
  91         [DIFF_FILE_NEW_MOVED_ALT_DIM] = "newMovedAlternativeDimmed",
  92 };
  93
  94 static NORETURN void die_want_option(const char *option_name)
  95 {
  96         die(_("option '%s' requires a value"), option_name);
  97 }
  98
  99 define_list_config_array_extra(color_diff_slots, {"plain"});
 100
 101 static int parse_diff_color_slot(const char *var)
 102 {
 103         if (!strcasecmp(var, "plain"))
 104                 return DIFF_CONTEXT;
 105         return LOOKUP_CONFIG(color_diff_slots, var);
 106 }
 107
 108 static int parse_dirstat_params(struct diff_options *options, const char *params_string,
 109                                 struct strbuf *errmsg)
 110 {
 111         char *params_copy = xstrdup(params_string);
 112         struct string_list params = STRING_LIST_INIT_NODUP;
 113         int ret = 0;
 114         int i;
 115
 116         if (*params_copy)
 117                 string_list_split_in_place(&params, params_copy, ',', -1);
 118         for (i = 0; i < params.nr; i++) {
 119                 const char *p = params.items[i].string;
 120                 if (!strcmp(p, "changes")) {
 121                         options->flags.dirstat_by_line = 0;
 122                         options->flags.dirstat_by_file = 0;
 123                 } else if (!strcmp(p, "lines")) {
 124                         options->flags.dirstat_by_line = 1;
 125                         options->flags.dirstat_by_file = 0;
 126                 } else if (!strcmp(p, "files")) {
 127                         options->flags.dirstat_by_line = 0;
 128                         options->flags.dirstat_by_file = 1;
 129                 } else if (!strcmp(p, "noncumulative")) {
 130                         options->flags.dirstat_cumulative = 0;
 131                 } else if (!strcmp(p, "cumulative")) {
 132                         options->flags.dirstat_cumulative = 1;
 133                 } else if (isdigit(*p)) {
 134                         char *end;
 135                         int permille = strtoul(p, &end, 10) * 10;
 136                         if (*end == '.' && isdigit(*++end)) {
 137                                 /* only use first digit */
 138                                 permille += *end - '0';
 139                                 /* .. and ignore any further digits */
 140                                 while (isdigit(*++end))
 141                                         ; /* nothing */
 142                         }
 143                         if (!*end)
 144                                 options->dirstat_permille = permille;
 145                         else {
 146                                 strbuf_addf(errmsg, _("  Failed to parse dirstat cut-off percentage '%s'\n"),
 147                                             p);
 148                                 ret++;
 149                         }
 150                 } else {
 151                         strbuf_addf(errmsg, _("  Unknown dirstat parameter '%s'\n"), p);
 152                         ret++;
 153                 }
 154
 155         }
 156         string_list_clear(&params, 0);
 157         free(params_copy);
 158         return ret;
 159 }
 160
 161 static int parse_submodule_params(struct diff_options *options, const char *value)
 162 {
 163         if (!strcmp(value, "log"))
 164                 options->submodule_format = DIFF_SUBMODULE_LOG;
 165         else if (!strcmp(value, "short"))
 166                 options->submodule_format = DIFF_SUBMODULE_SHORT;
 167         else if (!strcmp(value, "diff"))
 168                 options->submodule_format = DIFF_SUBMODULE_INLINE_DIFF;
 169         else
 170                 return -1;
 171         return 0;
 172 }
 173
 174 int git_config_rename(const char *var, const char *value)
 175 {
 176         if (!value)
 177                 return DIFF_DETECT_RENAME;
 178         if (!strcasecmp(value, "copies") || !strcasecmp(value, "copy"))
 179                 return  DIFF_DETECT_COPY;
 180         return git_config_bool(var,value) ? DIFF_DETECT_RENAME : 0;
 181 }
 182
 183 long parse_algorithm_value(const char *value)
 184 {
 185         if (!value)
 186                 return -1;
 187         else if (!strcasecmp(value, "myers") || !strcasecmp(value, "default"))
 188                 return 0;
 189         else if (!strcasecmp(value, "minimal"))
 190                 return XDF_NEED_MINIMAL;
 191         else if (!strcasecmp(value, "patience"))
 192                 return XDF_PATIENCE_DIFF;
 193         else if (!strcasecmp(value, "histogram"))
 194                 return XDF_HISTOGRAM_DIFF;
 195         return -1;
 196 }
 197
 198 static int parse_one_token(const char **arg, const char *token)
 199 {
 200         const char *rest;
 201         if (skip_prefix(*arg, token, &rest) && (!*rest || *rest == ',')) {
 202                 *arg = rest;
 203                 return 1;
 204         }
 205         return 0;
 206 }
 207
 208 static int parse_ws_error_highlight(const char *arg)
 209 {
 210         const char *orig_arg = arg;
 211         unsigned val = 0;
 212
 213         while (*arg) {
 214                 if (parse_one_token(&arg, "none"))
 215                         val = 0;
 216                 else if (parse_one_token(&arg, "default"))
 217                         val = WSEH_NEW;
 218                 else if (parse_one_token(&arg, "all"))
 219                         val = WSEH_NEW | WSEH_OLD | WSEH_CONTEXT;
 220                 else if (parse_one_token(&arg, "new"))
 221                         val |= WSEH_NEW;
 222                 else if (parse_one_token(&arg, "old"))
 223                         val |= WSEH_OLD;
 224                 else if (parse_one_token(&arg, "context"))
 225                         val |= WSEH_CONTEXT;
 226                 else {
 227                         return -1 - (int)(arg - orig_arg);
 228                 }
 229                 if (*arg)
 230                         arg++;
 231         }
 232         return val;
 233 }
 234
 235 /*
 236  * These are to give UI layer defaults.
 237  * The core-level commands such as git-diff-files should
 238  * never be affected by the setting of diff.renames
 239  * the user happens to have in the configuration file.
 240  */
 241 void init_diff_ui_defaults(void)
 242 {
 243         diff_detect_rename_default = DIFF_DETECT_RENAME;
 244 }
 245
 246 int git_diff_heuristic_config(const char *var, const char *value, void *cb)
 247 {
 248         if (!strcmp(var, "diff.indentheuristic"))
 249                 diff_indent_heuristic = git_config_bool(var, value);
 250         return 0;
 251 }
 252
 253 static int parse_color_moved(const char *arg)
 254 {
 255         switch (git_parse_maybe_bool(arg)) {
 256         case 0:
 257                 return COLOR_MOVED_NO;
 258         case 1:
 259                 return COLOR_MOVED_DEFAULT;
 260         default:
 261                 break;
 262         }
 263
 264         if (!strcmp(arg, "no"))
 265                 return COLOR_MOVED_NO;
 266         else if (!strcmp(arg, "plain"))
 267                 return COLOR_MOVED_PLAIN;
 268         else if (!strcmp(arg, "blocks"))
 269                 return COLOR_MOVED_BLOCKS;
 270         else if (!strcmp(arg, "zebra"))
 271                 return COLOR_MOVED_ZEBRA;
 272         else if (!strcmp(arg, "default"))
 273                 return COLOR_MOVED_DEFAULT;
 274         else if (!strcmp(arg, "dimmed-zebra"))
 275                 return COLOR_MOVED_ZEBRA_DIM;
 276         else if (!strcmp(arg, "dimmed_zebra"))
 277                 return COLOR_MOVED_ZEBRA_DIM;
 278         else
 279                 return error(_("color moved setting must be one of 'no', 'default', 'blocks', 'zebra', 'dimmed-zebra', 'plain'"));
 280 }
 281
 282 static int parse_color_moved_ws(const char *arg)
 283 {
 284         int ret = 0;
 285         struct string_list l = STRING_LIST_INIT_DUP;
 286         struct string_list_item *i;
 287
 288         string_list_split(&l, arg, ',', -1);
 289
 290         for_each_string_list_item(i, &l) {
 291                 struct strbuf sb = STRBUF_INIT;
 292                 strbuf_addstr(&sb, i->string);
 293                 strbuf_trim(&sb);
 294
 295                 if (!strcmp(sb.buf, "ignore-space-change"))
 296                         ret |= XDF_IGNORE_WHITESPACE_CHANGE;
 297                 else if (!strcmp(sb.buf, "ignore-space-at-eol"))
 298                         ret |= XDF_IGNORE_WHITESPACE_AT_EOL;
 299                 else if (!strcmp(sb.buf, "ignore-all-space"))
 300                         ret |= XDF_IGNORE_WHITESPACE;
 301                 else if (!strcmp(sb.buf, "allow-indentation-change"))
 302                         ret |= COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE;
 303                 else
 304                         error(_("ignoring unknown color-moved-ws mode '%s'"), sb.buf);
 305
 306                 strbuf_release(&sb);
 307         }
 308
 309         if ((ret & COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE) &&
 310             (ret & XDF_WHITESPACE_FLAGS))
 311                 die(_("color-moved-ws: allow-indentation-change cannot be combined with other white space modes"));
 312
 313         string_list_clear(&l, 0);
 314
 315         return ret;
 316 }
 317
 318 int git_diff_ui_config(const char *var, const char *value, void *cb)
 319 {
 320         if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 321                 diff_use_color_default = git_config_colorbool(var, value);
 322                 return 0;
 323         }
 324         if (!strcmp(var, "diff.colormoved")) {
 325                 int cm = parse_color_moved(value);
 326                 if (cm < 0)
 327                         return -1;
 328                 diff_color_moved_default = cm;
 329                 return 0;
 330         }
 331         if (!strcmp(var, "diff.colormovedws")) {
 332                 int cm = parse_color_moved_ws(value);
 333                 if (cm < 0)
 334                         return -1;
 335                 diff_color_moved_ws_default = cm;
 336                 return 0;
 337         }
 338         if (!strcmp(var, "diff.context")) {
 339                 diff_context_default = git_config_int(var, value);
 340                 if (diff_context_default < 0)
 341                         return -1;
 342                 return 0;
 343         }
 344         if (!strcmp(var, "diff.interhunkcontext")) {
 345                 diff_interhunk_context_default = git_config_int(var, value);
 346                 if (diff_interhunk_context_default < 0)
 347                         return -1;
 348                 return 0;
 349         }
 350         if (!strcmp(var, "diff.renames")) {
 351                 diff_detect_rename_default = git_config_rename(var, value);
 352                 return 0;
 353         }
 354         if (!strcmp(var, "diff.autorefreshindex")) {
 355                 diff_auto_refresh_index = git_config_bool(var, value);
 356                 return 0;
 357         }
 358         if (!strcmp(var, "diff.mnemonicprefix")) {
 359                 diff_mnemonic_prefix = git_config_bool(var, value);
 360                 return 0;
 361         }
 362         if (!strcmp(var, "diff.noprefix")) {
 363                 diff_no_prefix = git_config_bool(var, value);
 364                 return 0;
 365         }
 366         if (!strcmp(var, "diff.statgraphwidth")) {
 367                 diff_stat_graph_width = git_config_int(var, value);
 368                 return 0;
 369         }
 370         if (!strcmp(var, "diff.external"))
 371                 return git_config_string(&external_diff_cmd_cfg, var, value);
 372         if (!strcmp(var, "diff.wordregex"))
 373                 return git_config_string(&diff_word_regex_cfg, var, value);
 374         if (!strcmp(var, "diff.orderfile"))
 375                 return git_config_pathname(&diff_order_file_cfg, var, value);
 376
 377         if (!strcmp(var, "diff.ignoresubmodules"))
 378                 handle_ignore_submodules_arg(&default_diff_options, value);
 379
 380         if (!strcmp(var, "diff.submodule")) {
 381                 if (parse_submodule_params(&default_diff_options, value))
 382                         warning(_("Unknown value for 'diff.submodule' config variable: '%s'"),
 383                                 value);
 384                 return 0;
 385         }
 386
 387         if (!strcmp(var, "diff.algorithm")) {
 388                 diff_algorithm = parse_algorithm_value(value);
 389                 if (diff_algorithm < 0)
 390                         return -1;
 391                 return 0;
 392         }
 393
 394         if (!strcmp(var, "diff.wserrorhighlight")) {
 395                 int val = parse_ws_error_highlight(value);
 396                 if (val < 0)
 397                         return -1;
 398                 ws_error_highlight_default = val;
 399                 return 0;
 400         }
 401
 402         if (git_color_config(var, value, cb) < 0)
 403                 return -1;
 404
 405         return git_diff_basic_config(var, value, cb);
 406 }
 407
 408 int git_diff_basic_config(const char *var, const char *value, void *cb)
 409 {
 410         const char *name;
 411
 412         if (!strcmp(var, "diff.renamelimit")) {
 413                 diff_rename_limit_default = git_config_int(var, value);
 414                 return 0;
 415         }
 416
 417         if (userdiff_config(var, value) < 0)
 418                 return -1;
 419
 420         if (skip_prefix(var, "diff.color.", &name) ||
 421             skip_prefix(var, "color.diff.", &name)) {
 422                 int slot = parse_diff_color_slot(name);
 423                 if (slot < 0)
 424                         return 0;
 425                 if (!value)
 426                         return config_error_nonbool(var);
 427                 return color_parse(value, diff_colors[slot]);
 428         }
 429
 430         /* like GNU diff's --suppress-blank-empty option  */
 431         if (!strcmp(var, "diff.suppressblankempty") ||
 432                         /* for backwards compatibility */
 433                         !strcmp(var, "diff.suppress-blank-empty")) {
 434                 diff_suppress_blank_empty = git_config_bool(var, value);
 435                 return 0;
 436         }
 437
 438         if (!strcmp(var, "diff.dirstat")) {
 439                 struct strbuf errmsg = STRBUF_INIT;
 440                 default_diff_options.dirstat_permille = diff_dirstat_permille_default;
 441                 if (parse_dirstat_params(&default_diff_options, value, &errmsg))
 442                         warning(_("Found errors in 'diff.dirstat' config variable:\n%s"),
 443                                 errmsg.buf);
 444                 strbuf_release(&errmsg);
 445                 diff_dirstat_permille_default = default_diff_options.dirstat_permille;
 446                 return 0;
 447         }
 448
 449         if (git_diff_heuristic_config(var, value, cb) < 0)
 450                 return -1;
 451
 452         return git_default_config(var, value, cb);
 453 }
 454
 455 static char *quote_two(const char *one, const char *two)
 456 {
 457         int need_one = quote_c_style(one, NULL, NULL, 1);
 458         int need_two = quote_c_style(two, NULL, NULL, 1);
 459         struct strbuf res = STRBUF_INIT;
 460
 461         if (need_one + need_two) {
 462                 strbuf_addch(&res, '"');
 463                 quote_c_style(one, &res, NULL, 1);
 464                 quote_c_style(two, &res, NULL, 1);
 465                 strbuf_addch(&res, '"');
 466         } else {
 467                 strbuf_addstr(&res, one);
 468                 strbuf_addstr(&res, two);
 469         }
 470         return strbuf_detach(&res, NULL);
 471 }
 472
 473 static const char *external_diff(void)
 474 {
 475         static const char *external_diff_cmd = NULL;
 476         static int done_preparing = 0;
 477
 478         if (done_preparing)
 479                 return external_diff_cmd;
 480         external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 481         if (!external_diff_cmd)
 482                 external_diff_cmd = external_diff_cmd_cfg;
 483         done_preparing = 1;
 484         return external_diff_cmd;
 485 }
 486
 487 /*
 488  * Keep track of files used for diffing. Sometimes such an entry
 489  * refers to a temporary file, sometimes to an existing file, and
 490  * sometimes to "/dev/null".
 491  */
 492 static struct diff_tempfile {
 493         /*
 494          * filename external diff should read from, or NULL if this
 495          * entry is currently not in use:
 496          */
 497         const char *name;
 498
 499         char hex[GIT_MAX_HEXSZ + 1];
 500         char mode[10];
 501
 502         /*
 503          * If this diff_tempfile instance refers to a temporary file,
 504          * this tempfile object is used to manage its lifetime.
 505          */
 506         struct tempfile *tempfile;
 507 } diff_temp[2];
 508
 509 struct emit_callback {
 510         int color_diff;
 511         unsigned ws_rule;
 512         int blank_at_eof_in_preimage;
 513         int blank_at_eof_in_postimage;
 514         int lno_in_preimage;
 515         int lno_in_postimage;
 516         const char **label_path;
 517         struct diff_words_data *diff_words;
 518         struct diff_options *opt;
 519         struct strbuf *header;
 520 };
 521
 522 static int count_lines(const char *data, int size)
 523 {
 524         int count, ch, completely_empty = 1, nl_just_seen = 0;
 525         count = 0;
 526         while (0 < size--) {
 527                 ch = *data++;
 528                 if (ch == '\n') {
 529                         count++;
 530                         nl_just_seen = 1;
 531                         completely_empty = 0;
 532                 }
 533                 else {
 534                         nl_just_seen = 0;
 535                         completely_empty = 0;
 536                 }
 537         }
 538         if (completely_empty)
 539                 return 0;
 540         if (!nl_just_seen)
 541                 count++; /* no trailing newline */
 542         return count;
 543 }
 544
 545 static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 546 {
 547         if (!DIFF_FILE_VALID(one)) {
 548                 mf->ptr = (char *)""; /* does not matter */
 549                 mf->size = 0;
 550                 return 0;
 551         }
 552         else if (diff_populate_filespec(one, 0))
 553                 return -1;
 554
 555         mf->ptr = one->data;
 556         mf->size = one->size;
 557         return 0;
 558 }
 559
 560 /* like fill_mmfile, but only for size, so we can avoid retrieving blob */
 561 static unsigned long diff_filespec_size(struct diff_filespec *one)
 562 {
 563         if (!DIFF_FILE_VALID(one))
 564                 return 0;
 565         diff_populate_filespec(one, CHECK_SIZE_ONLY);
 566         return one->size;
 567 }
 568
 569 static int count_trailing_blank(mmfile_t *mf, unsigned ws_rule)
 570 {
 571         char *ptr = mf->ptr;
 572         long size = mf->size;
 573         int cnt = 0;
 574
 575         if (!size)
 576                 return cnt;
 577         ptr += size - 1; /* pointing at the very end */
 578         if (*ptr != '\n')
 579                 ; /* incomplete line */
 580         else
 581                 ptr--; /* skip the last LF */
 582         while (mf->ptr < ptr) {
 583                 char *prev_eol;
 584                 for (prev_eol = ptr; mf->ptr <= prev_eol; prev_eol--)
 585                         if (*prev_eol == '\n')
 586                                 break;
 587                 if (!ws_blank_line(prev_eol + 1, ptr - prev_eol, ws_rule))
 588                         break;
 589                 cnt++;
 590                 ptr = prev_eol - 1;
 591         }
 592         return cnt;
 593 }
 594
 595 static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
 596                                struct emit_callback *ecbdata)
 597 {
 598         int l1, l2, at;
 599         unsigned ws_rule = ecbdata->ws_rule;
 600         l1 = count_trailing_blank(mf1, ws_rule);
 601         l2 = count_trailing_blank(mf2, ws_rule);
 602         if (l2 <= l1) {
 603                 ecbdata->blank_at_eof_in_preimage = 0;
 604                 ecbdata->blank_at_eof_in_postimage = 0;
 605                 return;
 606         }
 607         at = count_lines(mf1->ptr, mf1->size);
 608         ecbdata->blank_at_eof_in_preimage = (at - l1) + 1;
 609
 610         at = count_lines(mf2->ptr, mf2->size);
 611         ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
 612 }
 613
 614 static void emit_line_0(struct diff_options *o, const char *set, const char *reset,
 615                         int first, const char *line, int len)
 616 {
 617         int has_trailing_newline, has_trailing_carriage_return;
 618         int nofirst;
 619         FILE *file = o->file;
 620
 621         fputs(diff_line_prefix(o), file);
 622
 623         if (len == 0) {
 624                 has_trailing_newline = (first == '\n');
 625                 has_trailing_carriage_return = (!has_trailing_newline &&
 626                                                 (first == '\r'));
 627                 nofirst = has_trailing_newline || has_trailing_carriage_return;
 628         } else {
 629                 has_trailing_newline = (len > 0 && line[len-1] == '\n');
 630                 if (has_trailing_newline)
 631                         len--;
 632                 has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
 633                 if (has_trailing_carriage_return)
 634                         len--;
 635                 nofirst = 0;
 636         }
 637
 638         if (len || !nofirst) {
 639                 fputs(set, file);
 640                 if (!nofirst)
 641                         fputc(first, file);
 642                 fwrite(line, len, 1, file);
 643                 fputs(reset, file);
 644         }
 645         if (has_trailing_carriage_return)
 646                 fputc('\r', file);
 647         if (has_trailing_newline)
 648                 fputc('\n', file);
 649 }
 650
 651 static void emit_line(struct diff_options *o, const char *set, const char *reset,
 652                       const char *line, int len)
 653 {
 654         emit_line_0(o, set, reset, line[0], line+1, len-1);
 655 }
 656
 657 enum diff_symbol {
 658         DIFF_SYMBOL_BINARY_DIFF_HEADER,
 659         DIFF_SYMBOL_BINARY_DIFF_HEADER_DELTA,
 660         DIFF_SYMBOL_BINARY_DIFF_HEADER_LITERAL,
 661         DIFF_SYMBOL_BINARY_DIFF_BODY,
 662         DIFF_SYMBOL_BINARY_DIFF_FOOTER,
 663         DIFF_SYMBOL_STATS_SUMMARY_NO_FILES,
 664         DIFF_SYMBOL_STATS_SUMMARY_ABBREV,
 665         DIFF_SYMBOL_STATS_SUMMARY_INSERTS_DELETES,
 666         DIFF_SYMBOL_STATS_LINE,
 667         DIFF_SYMBOL_WORD_DIFF,
 668         DIFF_SYMBOL_STAT_SEP,
 669         DIFF_SYMBOL_SUMMARY,
 670         DIFF_SYMBOL_SUBMODULE_ADD,
 671         DIFF_SYMBOL_SUBMODULE_DEL,
 672         DIFF_SYMBOL_SUBMODULE_UNTRACKED,
 673         DIFF_SYMBOL_SUBMODULE_MODIFIED,
 674         DIFF_SYMBOL_SUBMODULE_HEADER,
 675         DIFF_SYMBOL_SUBMODULE_ERROR,
 676         DIFF_SYMBOL_SUBMODULE_PIPETHROUGH,
 677         DIFF_SYMBOL_REWRITE_DIFF,
 678         DIFF_SYMBOL_BINARY_FILES,
 679         DIFF_SYMBOL_HEADER,
 680         DIFF_SYMBOL_FILEPAIR_PLUS,
 681         DIFF_SYMBOL_FILEPAIR_MINUS,
 682         DIFF_SYMBOL_WORDS_PORCELAIN,
 683         DIFF_SYMBOL_WORDS,
 684         DIFF_SYMBOL_CONTEXT,
 685         DIFF_SYMBOL_CONTEXT_INCOMPLETE,
 686         DIFF_SYMBOL_PLUS,
 687         DIFF_SYMBOL_MINUS,
 688         DIFF_SYMBOL_NO_LF_EOF,
 689         DIFF_SYMBOL_CONTEXT_FRAGINFO,
 690         DIFF_SYMBOL_CONTEXT_MARKER,
 691         DIFF_SYMBOL_SEPARATOR
 692 };
 693 /*
 694  * Flags for content lines:
 695  * 0..12 are whitespace rules
 696  * 13-15 are WSEH_NEW | WSEH_OLD | WSEH_CONTEXT
 697  * 16 is marking if the line is blank at EOF
 698  */
 699 #define DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF      (1<<16)
 700 #define DIFF_SYMBOL_MOVED_LINE                  (1<<17)
 701 #define DIFF_SYMBOL_MOVED_LINE_ALT              (1<<18)
 702 #define DIFF_SYMBOL_MOVED_LINE_UNINTERESTING    (1<<19)
 703 #define DIFF_SYMBOL_CONTENT_WS_MASK (WSEH_NEW | WSEH_OLD | WSEH_CONTEXT | WS_RULE_MASK)
 704
 705 /*
 706  * This struct is used when we need to buffer the output of the diff output.
 707  *
 708  * NEEDSWORK: Instead of storing a copy of the line, add an offset pointer
 709  * into the pre/post image file. This pointer could be a union with the
 710  * line pointer. By storing an offset into the file instead of the literal line,
 711  * we can decrease the memory footprint for the buffered output. At first we
 712  * may want to only have indirection for the content lines, but we could also
 713  * enhance the state for emitting prefabricated lines, e.g. the similarity
 714  * score line or hunk/file headers would only need to store a number or path
 715  * and then the output can be constructed later on depending on state.
 716  */
 717 struct emitted_diff_symbol {
 718         const char *line;
 719         int len;
 720         int flags;
 721         enum diff_symbol s;
 722 };
 723 #define EMITTED_DIFF_SYMBOL_INIT {NULL}
 724
 725 struct emitted_diff_symbols {
 726         struct emitted_diff_symbol *buf;
 727         int nr, alloc;
 728 };
 729 #define EMITTED_DIFF_SYMBOLS_INIT {NULL, 0, 0}
 730
 731 static void append_emitted_diff_symbol(struct diff_options *o,
 732                                        struct emitted_diff_symbol *e)
 733 {
 734         struct emitted_diff_symbol *f;
 735
 736         ALLOC_GROW(o->emitted_symbols->buf,
 737                    o->emitted_symbols->nr + 1,
 738                    o->emitted_symbols->alloc);
 739         f = &o->emitted_symbols->buf[o->emitted_symbols->nr++];
 740
 741         memcpy(f, e, sizeof(struct emitted_diff_symbol));
 742         f->line = e->line ? xmemdupz(e->line, e->len) : NULL;
 743 }
 744
 745 struct moved_entry {
 746         struct hashmap_entry ent;
 747         const struct emitted_diff_symbol *es;
 748         struct moved_entry *next_line;
 749         struct ws_delta *wsd;
 750 };
 751
 752 /**
 753  * The struct ws_delta holds white space differences between moved lines, i.e.
 754  * between '+' and '-' lines that have been detected to be a move.
 755  * The string contains the difference in leading white spaces, before the
 756  * rest of the line is compared using the white space config for move
 757  * coloring. The current_longer indicates if the first string in the
 758  * comparision is longer than the second.
 759  */
 760 struct ws_delta {
 761         char *string;
 762         unsigned int current_longer : 1;
 763 };
 764 #define WS_DELTA_INIT { NULL, 0 }
 765
 766 static int compute_ws_delta(const struct emitted_diff_symbol *a,
 767                              const struct emitted_diff_symbol *b,
 768                              struct ws_delta *out)
 769 {
 770         const struct emitted_diff_symbol *longer =  a->len > b->len ? a : b;
 771         const struct emitted_diff_symbol *shorter = a->len > b->len ? b : a;
 772         int d = longer->len - shorter->len;
 773
 774         out->string = xmemdupz(longer->line, d);
 775         out->current_longer = (a == longer);
 776
 777         return !strncmp(longer->line + d, shorter->line, shorter->len);
 778 }
 779
 780 static int cmp_in_block_with_wsd(const struct diff_options *o,
 781                                  const struct moved_entry *cur,
 782                                  const struct moved_entry *match,
 783                                  struct moved_entry *pmb,
 784                                  int n)
 785 {
 786         struct emitted_diff_symbol *l = &o->emitted_symbols->buf[n];
 787         int al = cur->es->len, cl = l->len;
 788         const char *a = cur->es->line,
 789                    *b = match->es->line,
 790                    *c = l->line;
 791
 792         int wslen;
 793
 794         /*
 795          * We need to check if 'cur' is equal to 'match'.
 796          * As those are from the same (+/-) side, we do not need to adjust for
 797          * indent changes. However these were found using fuzzy matching
 798          * so we do have to check if they are equal.
 799          */
 800         if (strcmp(a, b))
 801                 return 1;
 802
 803         if (!pmb->wsd)
 804                 /*
 805                  * No white space delta was carried forward? This can happen
 806                  * when we exit early in this function and do not carry
 807                  * forward ws.
 808                  */
 809                 return 1;
 810
 811         /*
 812          * The indent changes of the block are known and carried forward in
 813          * pmb->wsd; however we need to check if the indent changes of the
 814          * current line are still the same as before.
 815          *
 816          * To do so we need to compare 'l' to 'cur', adjusting the
 817          * one of them for the white spaces, depending which was longer.
 818          */
 819
 820         wslen = strlen(pmb->wsd->string);
 821         if (pmb->wsd->current_longer) {
 822                 c += wslen;
 823                 cl -= wslen;
 824         } else {
 825                 a += wslen;
 826                 al -= wslen;
 827         }
 828
 829         if (strcmp(a, c))
 830                 return 1;
 831
 832         return 0;
 833 }
 834
 835 static int moved_entry_cmp(const void *hashmap_cmp_fn_data,
 836                            const void *entry,
 837                            const void *entry_or_key,
 838                            const void *keydata)
 839 {
 840         const struct diff_options *diffopt = hashmap_cmp_fn_data;
 841         const struct moved_entry *a = entry;
 842         const struct moved_entry *b = entry_or_key;
 843         unsigned flags = diffopt->color_moved_ws_handling
 844                          & XDF_WHITESPACE_FLAGS;
 845
 846         if (diffopt->color_moved_ws_handling &
 847             COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE)
 848                 /*
 849                  * As there is not specific white space config given,
 850                  * we'd need to check for a new block, so ignore all
 851                  * white space. The setup of the white space
 852                  * configuration for the next block is done else where
 853                  */
 854                 flags |= XDF_IGNORE_WHITESPACE;
 855
 856         return !xdiff_compare_lines(a->es->line, a->es->len,
 857                                     b->es->line, b->es->len,
 858                                     flags);
 859 }
 860
 861 static struct moved_entry *prepare_entry(struct diff_options *o,
 862                                          int line_no)
 863 {
 864         struct moved_entry *ret = xmalloc(sizeof(*ret));
 865         struct emitted_diff_symbol *l = &o->emitted_symbols->buf[line_no];
 866         unsigned flags = o->color_moved_ws_handling & XDF_WHITESPACE_FLAGS;
 867
 868         ret->ent.hash = xdiff_hash_string(l->line, l->len, flags);
 869         ret->es = l;
 870         ret->next_line = NULL;
 871         ret->wsd = NULL;
 872
 873         return ret;
 874 }
 875
 876 static void add_lines_to_move_detection(struct diff_options *o,
 877                                         struct hashmap *add_lines,
 878                                         struct hashmap *del_lines)
 879 {
 880         struct moved_entry *prev_line = NULL;
 881
 882         int n;
 883         for (n = 0; n < o->emitted_symbols->nr; n++) {
 884                 struct hashmap *hm;
 885                 struct moved_entry *key;
 886
 887                 switch (o->emitted_symbols->buf[n].s) {
 888                 case DIFF_SYMBOL_PLUS:
 889                         hm = add_lines;
 890                         break;
 891                 case DIFF_SYMBOL_MINUS:
 892                         hm = del_lines;
 893                         break;
 894                 default:
 895                         prev_line = NULL;
 896                         continue;
 897                 }
 898
 899                 key = prepare_entry(o, n);
 900                 if (prev_line && prev_line->es->s == o->emitted_symbols->buf[n].s)
 901                         prev_line->next_line = key;
 902
 903                 hashmap_add(hm, key);
 904                 prev_line = key;
 905         }
 906 }
 907
 908 static void pmb_advance_or_null(struct diff_options *o,
 909                                 struct moved_entry *match,
 910                                 struct hashmap *hm,
 911                                 struct moved_entry **pmb,
 912                                 int pmb_nr)
 913 {
 914         int i;
 915         for (i = 0; i < pmb_nr; i++) {
 916                 struct moved_entry *prev = pmb[i];
 917                 struct moved_entry *cur = (prev && prev->next_line) ?
 918                                 prev->next_line : NULL;
 919                 if (cur && !hm->cmpfn(o, cur, match, NULL)) {
 920                         pmb[i] = cur;
 921                 } else {
 922                         pmb[i] = NULL;
 923                 }
 924         }
 925 }
 926
 927 static void pmb_advance_or_null_multi_match(struct diff_options *o,
 928                                             struct moved_entry *match,
 929                                             struct hashmap *hm,
 930                                             struct moved_entry **pmb,
 931                                             int pmb_nr, int n)
 932 {
 933         int i;
 934         char *got_match = xcalloc(1, pmb_nr);
 935
 936         for (; match; match = hashmap_get_next(hm, match)) {
 937                 for (i = 0; i < pmb_nr; i++) {
 938                         struct moved_entry *prev = pmb[i];
 939                         struct moved_entry *cur = (prev && prev->next_line) ?
 940                                         prev->next_line : NULL;
 941                         if (!cur)
 942                                 continue;
 943                         if (!cmp_in_block_with_wsd(o, cur, match, pmb[i], n))
 944                                 got_match[i] |= 1;
 945                 }
 946         }
 947
 948         for (i = 0; i < pmb_nr; i++) {
 949                 if (got_match[i]) {
 950                         /* Carry the white space delta forward */
 951                         pmb[i]->next_line->wsd = pmb[i]->wsd;
 952                         pmb[i] = pmb[i]->next_line;
 953                 } else
 954                         pmb[i] = NULL;
 955         }
 956 }
 957
 958 static int shrink_potential_moved_blocks(struct moved_entry **pmb,
 959                                          int pmb_nr)
 960 {
 961         int lp, rp;
 962
 963         /* Shrink the set of potential block to the remaining running */
 964         for (lp = 0, rp = pmb_nr - 1; lp <= rp;) {
 965                 while (lp < pmb_nr && pmb[lp])
 966                         lp++;
 967                 /* lp points at the first NULL now */
 968
 969                 while (rp > -1 && !pmb[rp])
 970                         rp--;
 971                 /* rp points at the last non-NULL */
 972
 973                 if (lp < pmb_nr && rp > -1 && lp < rp) {
 974                         pmb[lp] = pmb[rp];
 975                         if (pmb[rp]->wsd) {
 976                                 free(pmb[rp]->wsd->string);
 977                                 FREE_AND_NULL(pmb[rp]->wsd);
 978                         }
 979                         pmb[rp] = NULL;
 980                         rp--;
 981                         lp++;
 982                 }
 983         }
 984
 985         /* Remember the number of running sets */
 986         return rp + 1;
 987 }
 988
 989 /*
 990  * If o->color_moved is COLOR_MOVED_PLAIN, this function does nothing.
 991  *
 992  * Otherwise, if the last block has fewer alphanumeric characters than
 993  * COLOR_MOVED_MIN_ALNUM_COUNT, unset DIFF_SYMBOL_MOVED_LINE on all lines in
 994  * that block.
 995  *
 996  * The last block consists of the (n - block_length)'th line up to but not
 997  * including the nth line.
 998  *
 999  * NEEDSWORK: This uses the same heuristic as blame_entry_score() in blame.c.
1000  * Think of a way to unify them.
1001  */
1002 static void adjust_last_block(struct diff_options *o, int n, int block_length)
1003 {
1004         int i, alnum_count = 0;
1005         if (o->color_moved == COLOR_MOVED_PLAIN)
1006                 return;
1007         for (i = 1; i < block_length + 1; i++) {
1008                 const char *c = o->emitted_symbols->buf[n - i].line;
1009                 for (; *c; c++) {
1010                         if (!isalnum(*c))
1011                                 continue;
1012                         alnum_count++;
1013                         if (alnum_count >= COLOR_MOVED_MIN_ALNUM_COUNT)
1014                                 return;
1015                 }
1016         }
1017         for (i = 1; i < block_length + 1; i++)
1018                 o->emitted_symbols->buf[n - i].flags &= ~DIFF_SYMBOL_MOVED_LINE;
1019 }
1020
1021 /* Find blocks of moved code, delegate actual coloring decision to helper */
1022 static void mark_color_as_moved(struct diff_options *o,
1023                                 struct hashmap *add_lines,
1024                                 struct hashmap *del_lines)
1025 {
1026         struct moved_entry **pmb = NULL; /* potentially moved blocks */
1027         int pmb_nr = 0, pmb_alloc = 0;
1028         int n, flipped_block = 1, block_length = 0;
1029
1030
1031         for (n = 0; n < o->emitted_symbols->nr; n++) {
1032                 struct hashmap *hm = NULL;
1033                 struct moved_entry *key;
1034                 struct moved_entry *match = NULL;
1035                 struct emitted_diff_symbol *l = &o->emitted_symbols->buf[n];
1036
1037                 switch (l->s) {
1038                 case DIFF_SYMBOL_PLUS:
1039                         hm = del_lines;
1040                         key = prepare_entry(o, n);
1041                         match = hashmap_get(hm, key, NULL);
1042                         free(key);
1043                         break;
1044                 case DIFF_SYMBOL_MINUS:
1045                         hm = add_lines;
1046                         key = prepare_entry(o, n);
1047                         match = hashmap_get(hm, key, NULL);
1048                         free(key);
1049                         break;
1050                 default:
1051                         flipped_block = 1;
1052                 }
1053
1054                 if (!match) {
1055                         adjust_last_block(o, n, block_length);
1056                         pmb_nr = 0;
1057                         block_length = 0;
1058                         continue;
1059                 }
1060
1061                 l->flags |= DIFF_SYMBOL_MOVED_LINE;
1062
1063                 if (o->color_moved == COLOR_MOVED_PLAIN)
1064                         continue;
1065
1066                 if (o->color_moved_ws_handling &
1067                     COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE)
1068                         pmb_advance_or_null_multi_match(o, match, hm, pmb, pmb_nr, n);
1069                 else
1070                         pmb_advance_or_null(o, match, hm, pmb, pmb_nr);
1071
1072                 pmb_nr = shrink_potential_moved_blocks(pmb, pmb_nr);
1073
1074                 if (pmb_nr == 0) {
1075                         /*
1076                          * The current line is the start of a new block.
1077                          * Setup the set of potential blocks.
1078                          */
1079                         for (; match; match = hashmap_get_next(hm, match)) {
1080                                 ALLOC_GROW(pmb, pmb_nr + 1, pmb_alloc);
1081                                 if (o->color_moved_ws_handling &
1082                                     COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE) {
1083                                         struct ws_delta *wsd = xmalloc(sizeof(*match->wsd));
1084                                         if (compute_ws_delta(l, match->es, wsd)) {
1085                                                 match->wsd = wsd;
1086                                                 pmb[pmb_nr++] = match;
1087                                         } else
1088                                                 free(wsd);
1089                                 } else {
1090                                         pmb[pmb_nr++] = match;
1091                                 }
1092                         }
1093
1094                         flipped_block = (flipped_block + 1) % 2;
1095
1096                         adjust_last_block(o, n, block_length);
1097                         block_length = 0;
1098                 }
1099
1100                 block_length++;
1101
1102                 if (flipped_block && o->color_moved != COLOR_MOVED_BLOCKS)
1103                         l->flags |= DIFF_SYMBOL_MOVED_LINE_ALT;
1104         }
1105         adjust_last_block(o, n, block_length);
1106
1107         free(pmb);
1108 }
1109
1110 #define DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK \
1111   (DIFF_SYMBOL_MOVED_LINE | DIFF_SYMBOL_MOVED_LINE_ALT)
1112 static void dim_moved_lines(struct diff_options *o)
1113 {
1114         int n;
1115         for (n = 0; n < o->emitted_symbols->nr; n++) {
1116                 struct emitted_diff_symbol *prev = (n != 0) ?
1117                                 &o->emitted_symbols->buf[n - 1] : NULL;
1118                 struct emitted_diff_symbol *l = &o->emitted_symbols->buf[n];
1119                 struct emitted_diff_symbol *next =
1120                                 (n < o->emitted_symbols->nr - 1) ?
1121                                 &o->emitted_symbols->buf[n + 1] : NULL;
1122
1123                 /* Not a plus or minus line? */
1124                 if (l->s != DIFF_SYMBOL_PLUS && l->s != DIFF_SYMBOL_MINUS)
1125                         continue;
1126
1127                 /* Not a moved line? */
1128                 if (!(l->flags & DIFF_SYMBOL_MOVED_LINE))
1129                         continue;
1130
1131                 /*
1132                  * If prev or next are not a plus or minus line,
1133                  * pretend they don't exist
1134                  */
1135                 if (prev && prev->s != DIFF_SYMBOL_PLUS &&
1136                             prev->s != DIFF_SYMBOL_MINUS)
1137                         prev = NULL;
1138                 if (next && next->s != DIFF_SYMBOL_PLUS &&
1139                             next->s != DIFF_SYMBOL_MINUS)
1140                         next = NULL;
1141
1142                 /* Inside a block? */
1143                 if ((prev &&
1144                     (prev->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK) ==
1145                     (l->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK)) &&
1146                     (next &&
1147                     (next->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK) ==
1148                     (l->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK))) {
1149                         l->flags |= DIFF_SYMBOL_MOVED_LINE_UNINTERESTING;
1150                         continue;
1151                 }
1152
1153                 /* Check if we are at an interesting bound: */
1154                 if (prev && (prev->flags & DIFF_SYMBOL_MOVED_LINE) &&
1155                     (prev->flags & DIFF_SYMBOL_MOVED_LINE_ALT) !=
1156                        (l->flags & DIFF_SYMBOL_MOVED_LINE_ALT))
1157                         continue;
1158                 if (next && (next->flags & DIFF_SYMBOL_MOVED_LINE) &&
1159                     (next->flags & DIFF_SYMBOL_MOVED_LINE_ALT) !=
1160                        (l->flags & DIFF_SYMBOL_MOVED_LINE_ALT))
1161                         continue;
1162
1163                 /*
1164                  * The boundary to prev and next are not interesting,
1165                  * so this line is not interesting as a whole
1166                  */
1167                 l->flags |= DIFF_SYMBOL_MOVED_LINE_UNINTERESTING;
1168         }
1169 }
1170
1171 static void emit_line_ws_markup(struct diff_options *o,
1172                                 const char *set, const char *reset,
1173                                 const char *line, int len, char sign,
1174                                 unsigned ws_rule, int blank_at_eof)
1175 {
1176         const char *ws = NULL;
1177
1178         if (o->ws_error_highlight & ws_rule) {
1179                 ws = diff_get_color_opt(o, DIFF_WHITESPACE);
1180                 if (!*ws)
1181                         ws = NULL;
1182         }
1183
1184         if (!ws)
1185                 emit_line_0(o, set, reset, sign, line, len);
1186         else if (blank_at_eof)
1187                 /* Blank line at EOF - paint '+' as well */
1188                 emit_line_0(o, ws, reset, sign, line, len);
1189         else {
1190                 /* Emit just the prefix, then the rest. */
1191                 emit_line_0(o, set, reset, sign, "", 0);
1192                 ws_check_emit(line, len, ws_rule,
1193                               o->file, set, reset, ws);
1194         }
1195 }
1196
1197 static void emit_diff_symbol_from_struct(struct diff_options *o,
1198                                          struct emitted_diff_symbol *eds)
1199 {
1200         static const char *nneof = " No newline at end of file\n";
1201         const char *context, *reset, *set, *meta, *fraginfo;
1202         struct strbuf sb = STRBUF_INIT;
1203
1204         enum diff_symbol s = eds->s;
1205         const char *line = eds->line;
1206         int len = eds->len;
1207         unsigned flags = eds->flags;
1208
1209         switch (s) {
1210         case DIFF_SYMBOL_NO_LF_EOF:
1211                 context = diff_get_color_opt(o, DIFF_CONTEXT);
1212                 reset = diff_get_color_opt(o, DIFF_RESET);
1213                 putc('\n', o->file);
1214                 emit_line_0(o, context, reset, '\\',
1215                             nneof, strlen(nneof));
1216                 break;
1217         case DIFF_SYMBOL_SUBMODULE_HEADER:
1218         case DIFF_SYMBOL_SUBMODULE_ERROR:
1219         case DIFF_SYMBOL_SUBMODULE_PIPETHROUGH:
1220         case DIFF_SYMBOL_STATS_SUMMARY_INSERTS_DELETES:
1221         case DIFF_SYMBOL_SUMMARY:
1222         case DIFF_SYMBOL_STATS_LINE:
1223         case DIFF_SYMBOL_BINARY_DIFF_BODY:
1224         case DIFF_SYMBOL_CONTEXT_FRAGINFO:
1225                 emit_line(o, "", "", line, len);
1226                 break;
1227         case DIFF_SYMBOL_CONTEXT_INCOMPLETE:
1228         case DIFF_SYMBOL_CONTEXT_MARKER:
1229                 context = diff_get_color_opt(o, DIFF_CONTEXT);
1230                 reset = diff_get_color_opt(o, DIFF_RESET);
1231                 emit_line(o, context, reset, line, len);
1232                 break;
1233         case DIFF_SYMBOL_SEPARATOR:
1234                 fprintf(o->file, "%s%c",
1235                         diff_line_prefix(o),
1236                         o->line_termination);
1237                 break;
1238         case DIFF_SYMBOL_CONTEXT:
1239                 set = diff_get_color_opt(o, DIFF_CONTEXT);
1240                 reset = diff_get_color_opt(o, DIFF_RESET);
1241                 emit_line_ws_markup(o, set, reset, line, len, ' ',
1242                                     flags & (DIFF_SYMBOL_CONTENT_WS_MASK), 0);
1243                 break;
1244         case DIFF_SYMBOL_PLUS:
1245                 switch (flags & (DIFF_SYMBOL_MOVED_LINE |
1246                                  DIFF_SYMBOL_MOVED_LINE_ALT |
1247                                  DIFF_SYMBOL_MOVED_LINE_UNINTERESTING)) {
1248                 case DIFF_SYMBOL_MOVED_LINE |
1249                      DIFF_SYMBOL_MOVED_LINE_ALT |
1250                      DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1251                         set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED_ALT_DIM);
1252                         break;
1253                 case DIFF_SYMBOL_MOVED_LINE |
1254                      DIFF_SYMBOL_MOVED_LINE_ALT:
1255                         set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED_ALT);
1256                         break;
1257                 case DIFF_SYMBOL_MOVED_LINE |
1258                      DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1259                         set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED_DIM);
1260                         break;
1261                 case DIFF_SYMBOL_MOVED_LINE:
1262                         set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED);
1263                         break;
1264                 default:
1265                         set = diff_get_color_opt(o, DIFF_FILE_NEW);
1266                 }
1267                 reset = diff_get_color_opt(o, DIFF_RESET);
1268                 emit_line_ws_markup(o, set, reset, line, len, '+',
1269                                     flags & DIFF_SYMBOL_CONTENT_WS_MASK,
1270                                     flags & DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF);
1271                 break;
1272         case DIFF_SYMBOL_MINUS:
1273                 switch (flags & (DIFF_SYMBOL_MOVED_LINE |
1274                                  DIFF_SYMBOL_MOVED_LINE_ALT |
1275                                  DIFF_SYMBOL_MOVED_LINE_UNINTERESTING)) {
1276                 case DIFF_SYMBOL_MOVED_LINE |
1277                      DIFF_SYMBOL_MOVED_LINE_ALT |
1278                      DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1279                         set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED_ALT_DIM);
1280                         break;
1281                 case DIFF_SYMBOL_MOVED_LINE |
1282                      DIFF_SYMBOL_MOVED_LINE_ALT:
1283                         set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED_ALT);
1284                         break;
1285                 case DIFF_SYMBOL_MOVED_LINE |
1286                      DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1287                         set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED_DIM);
1288                         break;
1289                 case DIFF_SYMBOL_MOVED_LINE:
1290                         set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED);
1291                         break;
1292                 default:
1293                         set = diff_get_color_opt(o, DIFF_FILE_OLD);
1294                 }
1295                 reset = diff_get_color_opt(o, DIFF_RESET);
1296                 emit_line_ws_markup(o, set, reset, line, len, '-',
1297                                     flags & DIFF_SYMBOL_CONTENT_WS_MASK, 0);
1298                 break;
1299         case DIFF_SYMBOL_WORDS_PORCELAIN:
1300                 context = diff_get_color_opt(o, DIFF_CONTEXT);
1301                 reset = diff_get_color_opt(o, DIFF_RESET);
1302                 emit_line(o, context, reset, line, len);
1303                 fputs("~\n", o->file);
1304                 break;
1305         case DIFF_SYMBOL_WORDS:
1306                 context = diff_get_color_opt(o, DIFF_CONTEXT);
1307                 reset = diff_get_color_opt(o, DIFF_RESET);
1308                 /*
1309                  * Skip the prefix character, if any.  With
1310                  * diff_suppress_blank_empty, there may be
1311                  * none.
1312                  */
1313                 if (line[0] != '\n') {
1314                         line++;
1315                         len--;
1316                 }
1317                 emit_line(o, context, reset, line, len);
1318                 break;
1319         case DIFF_SYMBOL_FILEPAIR_PLUS:
1320                 meta = diff_get_color_opt(o, DIFF_METAINFO);
1321                 reset = diff_get_color_opt(o, DIFF_RESET);
1322                 fprintf(o->file, "%s%s+++ %s%s%s\n", diff_line_prefix(o), meta,
1323                         line, reset,
1324                         strchr(line, ' ') ? "\t" : "");
1325                 break;
1326         case DIFF_SYMBOL_FILEPAIR_MINUS:
1327                 meta = diff_get_color_opt(o, DIFF_METAINFO);
1328                 reset = diff_get_color_opt(o, DIFF_RESET);
1329                 fprintf(o->file, "%s%s--- %s%s%s\n", diff_line_prefix(o), meta,
1330                         line, reset,
1331                         strchr(line, ' ') ? "\t" : "");
1332                 break;
1333         case DIFF_SYMBOL_BINARY_FILES:
1334         case DIFF_SYMBOL_HEADER:
1335                 fprintf(o->file, "%s", line);
1336                 break;
1337         case DIFF_SYMBOL_BINARY_DIFF_HEADER:
1338                 fprintf(o->file, "%sGIT binary patch\n", diff_line_prefix(o));
1339                 break;
1340         case DIFF_SYMBOL_BINARY_DIFF_HEADER_DELTA:
1341                 fprintf(o->file, "%sdelta %s\n", diff_line_prefix(o), line);
1342                 break;
1343         case DIFF_SYMBOL_BINARY_DIFF_HEADER_LITERAL:
1344                 fprintf(o->file, "%sliteral %s\n", diff_line_prefix(o), line);
1345                 break;
1346         case DIFF_SYMBOL_BINARY_DIFF_FOOTER:
1347                 fputs(diff_line_prefix(o), o->file);
1348                 fputc('\n', o->file);
1349                 break;
1350         case DIFF_SYMBOL_REWRITE_DIFF:
1351                 fraginfo = diff_get_color(o->use_color, DIFF_FRAGINFO);
1352                 reset = diff_get_color_opt(o, DIFF_RESET);
1353                 emit_line(o, fraginfo, reset, line, len);
1354                 break;
1355         case DIFF_SYMBOL_SUBMODULE_ADD:
1356                 set = diff_get_color_opt(o, DIFF_FILE_NEW);
1357                 reset = diff_get_color_opt(o, DIFF_RESET);
1358                 emit_line(o, set, reset, line, len);
1359                 break;
1360         case DIFF_SYMBOL_SUBMODULE_DEL:
1361                 set = diff_get_color_opt(o, DIFF_FILE_OLD);
1362                 reset = diff_get_color_opt(o, DIFF_RESET);
1363                 emit_line(o, set, reset, line, len);
1364                 break;
1365         case DIFF_SYMBOL_SUBMODULE_UNTRACKED:
1366                 fprintf(o->file, "%sSubmodule %s contains untracked content\n",
1367                         diff_line_prefix(o), line);
1368                 break;
1369         case DIFF_SYMBOL_SUBMODULE_MODIFIED:
1370                 fprintf(o->file, "%sSubmodule %s contains modified content\n",
1371                         diff_line_prefix(o), line);
1372                 break;
1373         case DIFF_SYMBOL_STATS_SUMMARY_NO_FILES:
1374                 emit_line(o, "", "", " 0 files changed\n",
1375                           strlen(" 0 files changed\n"));
1376                 break;
1377         case DIFF_SYMBOL_STATS_SUMMARY_ABBREV:
1378                 emit_line(o, "", "", " ...\n", strlen(" ...\n"));
1379                 break;
1380         case DIFF_SYMBOL_WORD_DIFF:
1381                 fprintf(o->file, "%.*s", len, line);
1382                 break;
1383         case DIFF_SYMBOL_STAT_SEP:
1384                 fputs(o->stat_sep, o->file);
1385                 break;
1386         default:
1387                 BUG("unknown diff symbol");
1388         }
1389         strbuf_release(&sb);
1390 }
1391
1392 static void emit_diff_symbol(struct diff_options *o, enum diff_symbol s,
1393                              const char *line, int len, unsigned flags)
1394 {
1395         struct emitted_diff_symbol e = {line, len, flags, s};
1396
1397         if (o->emitted_symbols)
1398                 append_emitted_diff_symbol(o, &e);
1399         else
1400                 emit_diff_symbol_from_struct(o, &e);
1401 }
1402
1403 void diff_emit_submodule_del(struct diff_options *o, const char *line)
1404 {
1405         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_DEL, line, strlen(line), 0);
1406 }
1407
1408 void diff_emit_submodule_add(struct diff_options *o, const char *line)
1409 {
1410         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_ADD, line, strlen(line), 0);
1411 }
1412
1413 void diff_emit_submodule_untracked(struct diff_options *o, const char *path)
1414 {
1415         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_UNTRACKED,
1416                          path, strlen(path), 0);
1417 }
1418
1419 void diff_emit_submodule_modified(struct diff_options *o, const char *path)
1420 {
1421         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_MODIFIED,
1422                          path, strlen(path), 0);
1423 }
1424
1425 void diff_emit_submodule_header(struct diff_options *o, const char *header)
1426 {
1427         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_HEADER,
1428                          header, strlen(header), 0);
1429 }
1430
1431 void diff_emit_submodule_error(struct diff_options *o, const char *err)
1432 {
1433         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_ERROR, err, strlen(err), 0);
1434 }
1435
1436 void diff_emit_submodule_pipethrough(struct diff_options *o,
1437                                      const char *line, int len)
1438 {
1439         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_PIPETHROUGH, line, len, 0);
1440 }
1441
1442 static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
1443 {
1444         if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
1445               ecbdata->blank_at_eof_in_preimage &&
1446               ecbdata->blank_at_eof_in_postimage &&
1447               ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
1448               ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
1449                 return 0;
1450         return ws_blank_line(line, len, ecbdata->ws_rule);
1451 }
1452
1453 static void emit_add_line(const char *reset,
1454                           struct emit_callback *ecbdata,
1455                           const char *line, int len)
1456 {
1457         unsigned flags = WSEH_NEW | ecbdata->ws_rule;
1458         if (new_blank_line_at_eof(ecbdata, line, len))
1459                 flags |= DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF;
1460
1461         emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_PLUS, line, len, flags);
1462 }
1463
1464 static void emit_del_line(const char *reset,
1465                           struct emit_callback *ecbdata,
1466                           const char *line, int len)
1467 {
1468         unsigned flags = WSEH_OLD | ecbdata->ws_rule;
1469         emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_MINUS, line, len, flags);
1470 }
1471
1472 static void emit_context_line(const char *reset,
1473                               struct emit_callback *ecbdata,
1474                               const char *line, int len)
1475 {
1476         unsigned flags = WSEH_CONTEXT | ecbdata->ws_rule;
1477         emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_CONTEXT, line, len, flags);
1478 }
1479
1480 static void emit_hunk_header(struct emit_callback *ecbdata,
1481                              const char *line, int len)
1482 {
1483         const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
1484         const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
1485         const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
1486         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1487         static const char atat[2] = { '@', '@' };
1488         const char *cp, *ep;
1489         struct strbuf msgbuf = STRBUF_INIT;
1490         int org_len = len;
1491         int i = 1;
1492
1493         /*
1494          * As a hunk header must begin with "@@ -<old>, +<new> @@",
1495          * it always is at least 10 bytes long.
1496          */
1497         if (len < 10 ||
1498             memcmp(line, atat, 2) ||
1499             !(ep = memmem(line + 2, len - 2, atat, 2))) {
1500                 emit_diff_symbol(ecbdata->opt,
1501                                  DIFF_SYMBOL_CONTEXT_MARKER, line, len, 0);
1502                 return;
1503         }
1504         ep += 2; /* skip over @@ */
1505
1506         /* The hunk header in fraginfo color */
1507         strbuf_addstr(&msgbuf, frag);
1508         strbuf_add(&msgbuf, line, ep - line);
1509         strbuf_addstr(&msgbuf, reset);
1510
1511         /*
1512          * trailing "\r\n"
1513          */
1514         for ( ; i < 3; i++)
1515                 if (line[len - i] == '\r' || line[len - i] == '\n')
1516                         len--;
1517
1518         /* blank before the func header */
1519         for (cp = ep; ep - line < len; ep++)
1520                 if (*ep != ' ' && *ep != '\t')
1521                         break;
1522         if (ep != cp) {
1523                 strbuf_addstr(&msgbuf, context);
1524                 strbuf_add(&msgbuf, cp, ep - cp);
1525                 strbuf_addstr(&msgbuf, reset);
1526         }
1527
1528         if (ep < line + len) {
1529                 strbuf_addstr(&msgbuf, func);
1530                 strbuf_add(&msgbuf, ep, line + len - ep);
1531                 strbuf_addstr(&msgbuf, reset);
1532         }
1533
1534         strbuf_add(&msgbuf, line + len, org_len - len);
1535         strbuf_complete_line(&msgbuf);
1536         emit_diff_symbol(ecbdata->opt,
1537                          DIFF_SYMBOL_CONTEXT_FRAGINFO, msgbuf.buf, msgbuf.len, 0);
1538         strbuf_release(&msgbuf);
1539 }
1540
1541 static struct diff_tempfile *claim_diff_tempfile(void) {
1542         int i;
1543         for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
1544                 if (!diff_temp[i].name)
1545                         return diff_temp + i;
1546         BUG("diff is failing to clean up its tempfiles");
1547 }
1548
1549 static void remove_tempfile(void)
1550 {
1551         int i;
1552         for (i = 0; i < ARRAY_SIZE(diff_temp); i++) {
1553                 if (is_tempfile_active(diff_temp[i].tempfile))
1554                         delete_tempfile(&diff_temp[i].tempfile);
1555                 diff_temp[i].name = NULL;
1556         }
1557 }
1558
1559 static void add_line_count(struct strbuf *out, int count)
1560 {
1561         switch (count) {
1562         case 0:
1563                 strbuf_addstr(out, "0,0");
1564                 break;
1565         case 1:
1566                 strbuf_addstr(out, "1");
1567                 break;
1568         default:
1569                 strbuf_addf(out, "1,%d", count);
1570                 break;
1571         }
1572 }
1573
1574 static void emit_rewrite_lines(struct emit_callback *ecb,
1575                                int prefix, const char *data, int size)
1576 {
1577         const char *endp = NULL;
1578         const char *reset = diff_get_color(ecb->color_diff, DIFF_RESET);
1579
1580         while (0 < size) {
1581                 int len;
1582
1583                 endp = memchr(data, '\n', size);
1584                 len = endp ? (endp - data + 1) : size;
1585                 if (prefix != '+') {
1586                         ecb->lno_in_preimage++;
1587                         emit_del_line(reset, ecb, data, len);
1588                 } else {
1589                         ecb->lno_in_postimage++;
1590                         emit_add_line(reset, ecb, data, len);
1591                 }
1592                 size -= len;
1593                 data += len;
1594         }
1595         if (!endp)
1596                 emit_diff_symbol(ecb->opt, DIFF_SYMBOL_NO_LF_EOF, NULL, 0, 0);
1597 }
1598
1599 static void emit_rewrite_diff(const char *name_a,
1600                               const char *name_b,
1601                               struct diff_filespec *one,
1602                               struct diff_filespec *two,
1603                               struct userdiff_driver *textconv_one,
1604                               struct userdiff_driver *textconv_two,
1605                               struct diff_options *o)
1606 {
1607         int lc_a, lc_b;
1608         static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
1609         const char *a_prefix, *b_prefix;
1610         char *data_one, *data_two;
1611         size_t size_one, size_two;
1612         struct emit_callback ecbdata;
1613         struct strbuf out = STRBUF_INIT;
1614
1615         if (diff_mnemonic_prefix && o->flags.reverse_diff) {
1616                 a_prefix = o->b_prefix;
1617                 b_prefix = o->a_prefix;
1618         } else {
1619                 a_prefix = o->a_prefix;
1620                 b_prefix = o->b_prefix;
1621         }
1622
1623         name_a += (*name_a == '/');
1624         name_b += (*name_b == '/');
1625
1626         strbuf_reset(&a_name);
1627         strbuf_reset(&b_name);
1628         quote_two_c_style(&a_name, a_prefix, name_a, 0);
1629         quote_two_c_style(&b_name, b_prefix, name_b, 0);
1630
1631         size_one = fill_textconv(textconv_one, one, &data_one);
1632         size_two = fill_textconv(textconv_two, two, &data_two);
1633
1634         memset(&ecbdata, 0, sizeof(ecbdata));
1635         ecbdata.color_diff = want_color(o->use_color);
1636         ecbdata.ws_rule = whitespace_rule(name_b);
1637         ecbdata.opt = o;
1638         if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
1639                 mmfile_t mf1, mf2;
1640                 mf1.ptr = (char *)data_one;
1641                 mf2.ptr = (char *)data_two;
1642                 mf1.size = size_one;
1643                 mf2.size = size_two;
1644                 check_blank_at_eof(&mf1, &mf2, &ecbdata);
1645         }
1646         ecbdata.lno_in_preimage = 1;
1647         ecbdata.lno_in_postimage = 1;
1648
1649         lc_a = count_lines(data_one, size_one);
1650         lc_b = count_lines(data_two, size_two);
1651
1652         emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_MINUS,
1653                          a_name.buf, a_name.len, 0);
1654         emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_PLUS,
1655                          b_name.buf, b_name.len, 0);
1656
1657         strbuf_addstr(&out, "@@ -");
1658         if (!o->irreversible_delete)
1659                 add_line_count(&out, lc_a);
1660         else
1661                 strbuf_addstr(&out, "?,?");
1662         strbuf_addstr(&out, " +");
1663         add_line_count(&out, lc_b);
1664         strbuf_addstr(&out, " @@\n");
1665         emit_diff_symbol(o, DIFF_SYMBOL_REWRITE_DIFF, out.buf, out.len, 0);
1666         strbuf_release(&out);
1667
1668         if (lc_a && !o->irreversible_delete)
1669                 emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
1670         if (lc_b)
1671                 emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
1672         if (textconv_one)
1673                 free((char *)data_one);
1674         if (textconv_two)
1675                 free((char *)data_two);
1676 }
1677
1678 struct diff_words_buffer {
1679         mmfile_t text;
1680         unsigned long alloc;
1681         struct diff_words_orig {
1682                 const char *begin, *end;
1683         } *orig;
1684         int orig_nr, orig_alloc;
1685 };
1686
1687 static void diff_words_append(char *line, unsigned long len,
1688                 struct diff_words_buffer *buffer)
1689 {
1690         ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
1691         line++;
1692         len--;
1693         memcpy(buffer->text.ptr + buffer->text.size, line, len);
1694         buffer->text.size += len;
1695         buffer->text.ptr[buffer->text.size] = '\0';
1696 }
1697
1698 struct diff_words_style_elem {
1699         const char *prefix;
1700         const char *suffix;
1701         const char *color; /* NULL; filled in by the setup code if
1702                             * color is enabled */
1703 };
1704
1705 struct diff_words_style {
1706         enum diff_words_type type;
1707         struct diff_words_style_elem new_word, old_word, ctx;
1708         const char *newline;
1709 };
1710
1711 static struct diff_words_style diff_words_styles[] = {
1712         { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
1713         { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
1714         { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
1715 };
1716
1717 struct diff_words_data {
1718         struct diff_words_buffer minus, plus;
1719         const char *current_plus;
1720         int last_minus;
1721         struct diff_options *opt;
1722         regex_t *word_regex;
1723         enum diff_words_type type;
1724         struct diff_words_style *style;
1725 };
1726
1727 static int fn_out_diff_words_write_helper(struct diff_options *o,
1728                                           struct diff_words_style_elem *st_el,
1729                                           const char *newline,
1730                                           size_t count, const char *buf)
1731 {
1732         int print = 0;
1733         struct strbuf sb = STRBUF_INIT;
1734
1735         while (count) {
1736                 char *p = memchr(buf, '\n', count);
1737                 if (print)
1738                         strbuf_addstr(&sb, diff_line_prefix(o));
1739
1740                 if (p != buf) {
1741                         const char *reset = st_el->color && *st_el->color ?
1742                                             GIT_COLOR_RESET : NULL;
1743                         if (st_el->color && *st_el->color)
1744                                 strbuf_addstr(&sb, st_el->color);
1745                         strbuf_addstr(&sb, st_el->prefix);
1746                         strbuf_add(&sb, buf, p ? p - buf : count);
1747                         strbuf_addstr(&sb, st_el->suffix);
1748                         if (reset)
1749                                 strbuf_addstr(&sb, reset);
1750                 }
1751                 if (!p)
1752                         goto out;
1753
1754                 strbuf_addstr(&sb, newline);
1755                 count -= p + 1 - buf;
1756                 buf = p + 1;
1757                 print = 1;
1758                 if (count) {
1759                         emit_diff_symbol(o, DIFF_SYMBOL_WORD_DIFF,
1760                                          sb.buf, sb.len, 0);
1761                         strbuf_reset(&sb);
1762                 }
1763         }
1764
1765 out:
1766         if (sb.len)
1767                 emit_diff_symbol(o, DIFF_SYMBOL_WORD_DIFF,
1768                                  sb.buf, sb.len, 0);
1769         strbuf_release(&sb);
1770         return 0;
1771 }
1772
1773 /*
1774  * '--color-words' algorithm can be described as:
1775  *
1776  *   1. collect the minus/plus lines of a diff hunk, divided into
1777  *      minus-lines and plus-lines;
1778  *
1779  *   2. break both minus-lines and plus-lines into words and
1780  *      place them into two mmfile_t with one word for each line;
1781  *
1782  *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
1783  *
1784  * And for the common parts of the both file, we output the plus side text.
1785  * diff_words->current_plus is used to trace the current position of the plus file
1786  * which printed. diff_words->last_minus is used to trace the last minus word
1787  * printed.
1788  *
1789  * For '--graph' to work with '--color-words', we need to output the graph prefix
1790  * on each line of color words output. Generally, there are two conditions on
1791  * which we should output the prefix.
1792  *
1793  *   1. diff_words->last_minus == 0 &&
1794  *      diff_words->current_plus == diff_words->plus.text.ptr
1795  *
1796  *      that is: the plus text must start as a new line, and if there is no minus
1797  *      word printed, a graph prefix must be printed.
1798  *
1799  *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
1800  *      *(diff_words->current_plus - 1) == '\n'
1801  *
1802  *      that is: a graph prefix must be printed following a '\n'
1803  */
1804 static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
1805 {
1806         if ((diff_words->last_minus == 0 &&
1807                 diff_words->current_plus == diff_words->plus.text.ptr) ||
1808                 (diff_words->current_plus > diff_words->plus.text.ptr &&
1809                 *(diff_words->current_plus - 1) == '\n')) {
1810                 return 1;
1811         } else {
1812                 return 0;
1813         }
1814 }
1815
1816 static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
1817 {
1818         struct diff_words_data *diff_words = priv;
1819         struct diff_words_style *style = diff_words->style;
1820         int minus_first, minus_len, plus_first, plus_len;
1821         const char *minus_begin, *minus_end, *plus_begin, *plus_end;
1822         struct diff_options *opt = diff_words->opt;
1823         const char *line_prefix;
1824
1825         if (line[0] != '@' || parse_hunk_header(line, len,
1826                         &minus_first, &minus_len, &plus_first, &plus_len))
1827                 return;
1828
1829         assert(opt);
1830         line_prefix = diff_line_prefix(opt);
1831
1832         /* POSIX requires that first be decremented by one if len == 0... */
1833         if (minus_len) {
1834                 minus_begin = diff_words->minus.orig[minus_first].begin;
1835                 minus_end =
1836                         diff_words->minus.orig[minus_first + minus_len - 1].end;
1837         } else
1838                 minus_begin = minus_end =
1839                         diff_words->minus.orig[minus_first].end;
1840
1841         if (plus_len) {
1842                 plus_begin = diff_words->plus.orig[plus_first].begin;
1843                 plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
1844         } else
1845                 plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
1846
1847         if (color_words_output_graph_prefix(diff_words)) {
1848                 fputs(line_prefix, diff_words->opt->file);
1849         }
1850         if (diff_words->current_plus != plus_begin) {
1851                 fn_out_diff_words_write_helper(diff_words->opt,
1852                                 &style->ctx, style->newline,
1853                                 plus_begin - diff_words->current_plus,
1854                                 diff_words->current_plus);
1855         }
1856         if (minus_begin != minus_end) {
1857                 fn_out_diff_words_write_helper(diff_words->opt,
1858                                 &style->old_word, style->newline,
1859                                 minus_end - minus_begin, minus_begin);
1860         }
1861         if (plus_begin != plus_end) {
1862                 fn_out_diff_words_write_helper(diff_words->opt,
1863                                 &style->new_word, style->newline,
1864                                 plus_end - plus_begin, plus_begin);
1865         }
1866
1867         diff_words->current_plus = plus_end;
1868         diff_words->last_minus = minus_first;
1869 }
1870
1871 /* This function starts looking at *begin, and returns 0 iff a word was found. */
1872 static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
1873                 int *begin, int *end)
1874 {
1875         if (word_regex && *begin < buffer->size) {
1876                 regmatch_t match[1];
1877                 if (!regexec_buf(word_regex, buffer->ptr + *begin,
1878                                  buffer->size - *begin, 1, match, 0)) {
1879                         char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
1880                                         '\n', match[0].rm_eo - match[0].rm_so);
1881                         *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
1882                         *begin += match[0].rm_so;
1883                         return *begin >= *end;
1884                 }
1885                 return -1;
1886         }
1887
1888         /* find the next word */
1889         while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
1890                 (*begin)++;
1891         if (*begin >= buffer->size)
1892                 return -1;
1893
1894         /* find the end of the word */
1895         *end = *begin + 1;
1896         while (*end < buffer->size && !isspace(buffer->ptr[*end]))
1897                 (*end)++;
1898
1899         return 0;
1900 }
1901
1902 /*
1903  * This function splits the words in buffer->text, stores the list with
1904  * newline separator into out, and saves the offsets of the original words
1905  * in buffer->orig.
1906  */
1907 static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
1908                 regex_t *word_regex)
1909 {
1910         int i, j;
1911         long alloc = 0;
1912
1913         out->size = 0;
1914         out->ptr = NULL;
1915
1916         /* fake an empty "0th" word */
1917         ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
1918         buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
1919         buffer->orig_nr = 1;
1920
1921         for (i = 0; i < buffer->text.size; i++) {
1922                 if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
1923                         return;
1924
1925                 /* store original boundaries */
1926                 ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
1927                                 buffer->orig_alloc);
1928                 buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
1929                 buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
1930                 buffer->orig_nr++;
1931
1932                 /* store one word */
1933                 ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
1934                 memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
1935                 out->ptr[out->size + j - i] = '\n';
1936                 out->size += j - i + 1;
1937
1938                 i = j - 1;
1939         }
1940 }
1941
1942 /* this executes the word diff on the accumulated buffers */
1943 static void diff_words_show(struct diff_words_data *diff_words)
1944 {
1945         xpparam_t xpp;
1946         xdemitconf_t xecfg;
1947         mmfile_t minus, plus;
1948         struct diff_words_style *style = diff_words->style;
1949
1950         struct diff_options *opt = diff_words->opt;
1951         const char *line_prefix;
1952
1953         assert(opt);
1954         line_prefix = diff_line_prefix(opt);
1955
1956         /* special case: only removal */
1957         if (!diff_words->plus.text.size) {
1958                 emit_diff_symbol(diff_words->opt, DIFF_SYMBOL_WORD_DIFF,
1959                                  line_prefix, strlen(line_prefix), 0);
1960                 fn_out_diff_words_write_helper(diff_words->opt,
1961                         &style->old_word, style->newline,
1962                         diff_words->minus.text.size,
1963                         diff_words->minus.text.ptr);
1964                 diff_words->minus.text.size = 0;
1965                 return;
1966         }
1967
1968         diff_words->current_plus = diff_words->plus.text.ptr;
1969         diff_words->last_minus = 0;
1970
1971         memset(&xpp, 0, sizeof(xpp));
1972         memset(&xecfg, 0, sizeof(xecfg));
1973         diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
1974         diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
1975         xpp.flags = 0;
1976         /* as only the hunk header will be parsed, we need a 0-context */
1977         xecfg.ctxlen = 0;
1978         if (xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
1979                           &xpp, &xecfg))
1980                 die("unable to generate word diff");
1981         free(minus.ptr);
1982         free(plus.ptr);
1983         if (diff_words->current_plus != diff_words->plus.text.ptr +
1984                         diff_words->plus.text.size) {
1985                 if (color_words_output_graph_prefix(diff_words))
1986                         emit_diff_symbol(diff_words->opt, DIFF_SYMBOL_WORD_DIFF,
1987                                          line_prefix, strlen(line_prefix), 0);
1988                 fn_out_diff_words_write_helper(diff_words->opt,
1989                         &style->ctx, style->newline,
1990                         diff_words->plus.text.ptr + diff_words->plus.text.size
1991                         - diff_words->current_plus, diff_words->current_plus);
1992         }
1993         diff_words->minus.text.size = diff_words->plus.text.size = 0;
1994 }
1995
1996 /* In "color-words" mode, show word-diff of words accumulated in the buffer */
1997 static void diff_words_flush(struct emit_callback *ecbdata)
1998 {
1999         struct diff_options *wo = ecbdata->diff_words->opt;
2000
2001         if (ecbdata->diff_words->minus.text.size ||
2002             ecbdata->diff_words->plus.text.size)
2003                 diff_words_show(ecbdata->diff_words);
2004
2005         if (wo->emitted_symbols) {
2006                 struct diff_options *o = ecbdata->opt;
2007                 struct emitted_diff_symbols *wol = wo->emitted_symbols;
2008                 int i;
2009
2010                 /*
2011                  * NEEDSWORK:
2012                  * Instead of appending each, concat all words to a line?
2013                  */
2014                 for (i = 0; i < wol->nr; i++)
2015                         append_emitted_diff_symbol(o, &wol->buf[i]);
2016
2017                 for (i = 0; i < wol->nr; i++)
2018                         free((void *)wol->buf[i].line);
2019
2020                 wol->nr = 0;
2021         }
2022 }
2023
2024 static void diff_filespec_load_driver(struct diff_filespec *one)
2025 {
2026         /* Use already-loaded driver */
2027         if (one->driver)
2028                 return;
2029
2030         if (S_ISREG(one->mode))
2031                 one->driver = userdiff_find_by_path(one->path);
2032
2033         /* Fallback to default settings */
2034         if (!one->driver)
2035                 one->driver = userdiff_find_by_name("default");
2036 }
2037
2038 static const char *userdiff_word_regex(struct diff_filespec *one)
2039 {
2040         diff_filespec_load_driver(one);
2041         return one->driver->word_regex;
2042 }
2043
2044 static void init_diff_words_data(struct emit_callback *ecbdata,
2045                                  struct diff_options *orig_opts,
2046                                  struct diff_filespec *one,
2047                                  struct diff_filespec *two)
2048 {
2049         int i;
2050         struct diff_options *o = xmalloc(sizeof(struct diff_options));
2051         memcpy(o, orig_opts, sizeof(struct diff_options));
2052
2053         ecbdata->diff_words =
2054                 xcalloc(1, sizeof(struct diff_words_data));
2055         ecbdata->diff_words->type = o->word_diff;
2056         ecbdata->diff_words->opt = o;
2057
2058         if (orig_opts->emitted_symbols)
2059                 o->emitted_symbols =
2060                         xcalloc(1, sizeof(struct emitted_diff_symbols));
2061
2062         if (!o->word_regex)
2063                 o->word_regex = userdiff_word_regex(one);
2064         if (!o->word_regex)
2065                 o->word_regex = userdiff_word_regex(two);
2066         if (!o->word_regex)
2067                 o->word_regex = diff_word_regex_cfg;
2068         if (o->word_regex) {
2069                 ecbdata->diff_words->word_regex = (regex_t *)
2070                         xmalloc(sizeof(regex_t));
2071                 if (regcomp(ecbdata->diff_words->word_regex,
2072                             o->word_regex,
2073                             REG_EXTENDED | REG_NEWLINE))
2074                         die ("Invalid regular expression: %s",
2075                              o->word_regex);
2076         }
2077         for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
2078                 if (o->word_diff == diff_words_styles[i].type) {
2079                         ecbdata->diff_words->style =
2080                                 &diff_words_styles[i];
2081                         break;
2082                 }
2083         }
2084         if (want_color(o->use_color)) {
2085                 struct diff_words_style *st = ecbdata->diff_words->style;
2086                 st->old_word.color = diff_get_color_opt(o, DIFF_FILE_OLD);
2087                 st->new_word.color = diff_get_color_opt(o, DIFF_FILE_NEW);
2088                 st->ctx.color = diff_get_color_opt(o, DIFF_CONTEXT);
2089         }
2090 }
2091
2092 static void free_diff_words_data(struct emit_callback *ecbdata)
2093 {
2094         if (ecbdata->diff_words) {
2095                 diff_words_flush(ecbdata);
2096                 free (ecbdata->diff_words->opt->emitted_symbols);
2097                 free (ecbdata->diff_words->opt);
2098                 free (ecbdata->diff_words->minus.text.ptr);
2099                 free (ecbdata->diff_words->minus.orig);
2100                 free (ecbdata->diff_words->plus.text.ptr);
2101                 free (ecbdata->diff_words->plus.orig);
2102                 if (ecbdata->diff_words->word_regex) {
2103                         regfree(ecbdata->diff_words->word_regex);
2104                         free(ecbdata->diff_words->word_regex);
2105                 }
2106                 FREE_AND_NULL(ecbdata->diff_words);
2107         }
2108 }
2109
2110 const char *diff_get_color(int diff_use_color, enum color_diff ix)
2111 {
2112         if (want_color(diff_use_color))
2113                 return diff_colors[ix];
2114         return "";
2115 }
2116
2117 const char *diff_line_prefix(struct diff_options *opt)
2118 {
2119         struct strbuf *msgbuf;
2120         if (!opt->output_prefix)
2121                 return "";
2122
2123         msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
2124         return msgbuf->buf;
2125 }
2126
2127 static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
2128 {
2129         const char *cp;
2130         unsigned long allot;
2131         size_t l = len;
2132
2133         cp = line;
2134         allot = l;
2135         while (0 < l) {
2136                 (void) utf8_width(&cp, &l);
2137                 if (!cp)
2138                         break; /* truncated in the middle? */
2139         }
2140         return allot - l;
2141 }
2142
2143 static void find_lno(const char *line, struct emit_callback *ecbdata)
2144 {
2145         const char *p;
2146         ecbdata->lno_in_preimage = 0;
2147         ecbdata->lno_in_postimage = 0;
2148         p = strchr(line, '-');
2149         if (!p)
2150                 return; /* cannot happen */
2151         ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
2152         p = strchr(p, '+');
2153         if (!p)
2154                 return; /* cannot happen */
2155         ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
2156 }
2157
2158 static void fn_out_consume(void *priv, char *line, unsigned long len)
2159 {
2160         struct emit_callback *ecbdata = priv;
2161         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
2162         struct diff_options *o = ecbdata->opt;
2163
2164         o->found_changes = 1;
2165
2166         if (ecbdata->header) {
2167                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
2168                                  ecbdata->header->buf, ecbdata->header->len, 0);
2169                 strbuf_reset(ecbdata->header);
2170                 ecbdata->header = NULL;
2171         }
2172
2173         if (ecbdata->label_path[0]) {
2174                 emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_MINUS,
2175                                  ecbdata->label_path[0],
2176                                  strlen(ecbdata->label_path[0]), 0);
2177                 emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_PLUS,
2178                                  ecbdata->label_path[1],
2179                                  strlen(ecbdata->label_path[1]), 0);
2180                 ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
2181         }
2182
2183         if (diff_suppress_blank_empty
2184             && len == 2 && line[0] == ' ' && line[1] == '\n') {
2185                 line[0] = '\n';
2186                 len = 1;
2187         }
2188
2189         if (line[0] == '@') {
2190                 if (ecbdata->diff_words)
2191                         diff_words_flush(ecbdata);
2192                 len = sane_truncate_line(ecbdata, line, len);
2193                 find_lno(line, ecbdata);
2194                 emit_hunk_header(ecbdata, line, len);
2195                 return;
2196         }
2197
2198         if (ecbdata->diff_words) {
2199                 enum diff_symbol s =
2200                         ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN ?
2201                         DIFF_SYMBOL_WORDS_PORCELAIN : DIFF_SYMBOL_WORDS;
2202                 if (line[0] == '-') {
2203                         diff_words_append(line, len,
2204                                           &ecbdata->diff_words->minus);
2205                         return;
2206                 } else if (line[0] == '+') {
2207                         diff_words_append(line, len,
2208                                           &ecbdata->diff_words->plus);
2209                         return;
2210                 } else if (starts_with(line, "\\ ")) {
2211                         /*
2212                          * Eat the "no newline at eof" marker as if we
2213                          * saw a "+" or "-" line with nothing on it,
2214                          * and return without diff_words_flush() to
2215                          * defer processing. If this is the end of
2216                          * preimage, more "+" lines may come after it.
2217                          */
2218                         return;
2219                 }
2220                 diff_words_flush(ecbdata);
2221                 emit_diff_symbol(o, s, line, len, 0);
2222                 return;
2223         }
2224
2225         switch (line[0]) {
2226         case '+':
2227                 ecbdata->lno_in_postimage++;
2228                 emit_add_line(reset, ecbdata, line + 1, len - 1);
2229                 break;
2230         case '-':
2231                 ecbdata->lno_in_preimage++;
2232                 emit_del_line(reset, ecbdata, line + 1, len - 1);
2233                 break;
2234         case ' ':
2235                 ecbdata->lno_in_postimage++;
2236                 ecbdata->lno_in_preimage++;
2237                 emit_context_line(reset, ecbdata, line + 1, len - 1);
2238                 break;
2239         default:
2240                 /* incomplete line at the end */
2241                 ecbdata->lno_in_preimage++;
2242                 emit_diff_symbol(o, DIFF_SYMBOL_CONTEXT_INCOMPLETE,
2243                                  line, len, 0);
2244                 break;
2245         }
2246 }
2247
2248 static void pprint_rename(struct strbuf *name, const char *a, const char *b)
2249 {
2250         const char *old_name = a;
2251         const char *new_name = b;
2252         int pfx_length, sfx_length;
2253         int pfx_adjust_for_slash;
2254         int len_a = strlen(a);
2255         int len_b = strlen(b);
2256         int a_midlen, b_midlen;
2257         int qlen_a = quote_c_style(a, NULL, NULL, 0);
2258         int qlen_b = quote_c_style(b, NULL, NULL, 0);
2259
2260         if (qlen_a || qlen_b) {
2261                 quote_c_style(a, name, NULL, 0);
2262                 strbuf_addstr(name, " => ");
2263                 quote_c_style(b, name, NULL, 0);
2264                 return;
2265         }
2266
2267         /* Find common prefix */
2268         pfx_length = 0;
2269         while (*old_name && *new_name && *old_name == *new_name) {
2270                 if (*old_name == '/')
2271                         pfx_length = old_name - a + 1;
2272                 old_name++;
2273                 new_name++;
2274         }
2275
2276         /* Find common suffix */
2277         old_name = a + len_a;
2278         new_name = b + len_b;
2279         sfx_length = 0;
2280         /*
2281          * If there is a common prefix, it must end in a slash.  In
2282          * that case we let this loop run 1 into the prefix to see the
2283          * same slash.
2284          *
2285          * If there is no common prefix, we cannot do this as it would
2286          * underrun the input strings.
2287          */
2288         pfx_adjust_for_slash = (pfx_length ? 1 : 0);
2289         while (a + pfx_length - pfx_adjust_for_slash <= old_name &&
2290                b + pfx_length - pfx_adjust_for_slash <= new_name &&
2291                *old_name == *new_name) {
2292                 if (*old_name == '/')
2293                         sfx_length = len_a - (old_name - a);
2294                 old_name--;
2295                 new_name--;
2296         }
2297
2298         /*
2299          * pfx{mid-a => mid-b}sfx
2300          * {pfx-a => pfx-b}sfx
2301          * pfx{sfx-a => sfx-b}
2302          * name-a => name-b
2303          */
2304         a_midlen = len_a - pfx_length - sfx_length;
2305         b_midlen = len_b - pfx_length - sfx_length;
2306         if (a_midlen < 0)
2307                 a_midlen = 0;
2308         if (b_midlen < 0)
2309                 b_midlen = 0;
2310
2311         strbuf_grow(name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
2312         if (pfx_length + sfx_length) {
2313                 strbuf_add(name, a, pfx_length);
2314                 strbuf_addch(name, '{');
2315         }
2316         strbuf_add(name, a + pfx_length, a_midlen);
2317         strbuf_addstr(name, " => ");
2318         strbuf_add(name, b + pfx_length, b_midlen);
2319         if (pfx_length + sfx_length) {
2320                 strbuf_addch(name, '}');
2321                 strbuf_add(name, a + len_a - sfx_length, sfx_length);
2322         }
2323 }
2324
2325 struct diffstat_t {
2326         int nr;
2327         int alloc;
2328         struct diffstat_file {
2329                 char *from_name;
2330                 char *name;
2331                 char *print_name;
2332                 const char *comments;
2333                 unsigned is_unmerged:1;
2334                 unsigned is_binary:1;
2335                 unsigned is_renamed:1;
2336                 unsigned is_interesting:1;
2337                 uintmax_t added, deleted;
2338         } **files;
2339 };
2340
2341 static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
2342                                           const char *name_a,
2343                                           const char *name_b)
2344 {
2345         struct diffstat_file *x;
2346         x = xcalloc(1, sizeof(*x));
2347         ALLOC_GROW(diffstat->files, diffstat->nr + 1, diffstat->alloc);
2348         diffstat->files[diffstat->nr++] = x;
2349         if (name_b) {
2350                 x->from_name = xstrdup(name_a);
2351                 x->name = xstrdup(name_b);
2352                 x->is_renamed = 1;
2353         }
2354         else {
2355                 x->from_name = NULL;
2356                 x->name = xstrdup(name_a);
2357         }
2358         return x;
2359 }
2360
2361 static void diffstat_consume(void *priv, char *line, unsigned long len)
2362 {
2363         struct diffstat_t *diffstat = priv;
2364         struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
2365
2366         if (line[0] == '+')
2367                 x->added++;
2368         else if (line[0] == '-')
2369                 x->deleted++;
2370 }
2371
2372 const char mime_boundary_leader[] = "------------";
2373
2374 static int scale_linear(int it, int width, int max_change)
2375 {
2376         if (!it)
2377                 return 0;
2378         /*
2379          * make sure that at least one '-' or '+' is printed if
2380          * there is any change to this path. The easiest way is to
2381          * scale linearly as if the alloted width is one column shorter
2382          * than it is, and then add 1 to the result.
2383          */
2384         return 1 + (it * (width - 1) / max_change);
2385 }
2386
2387 static void show_graph(struct strbuf *out, char ch, int cnt,
2388                        const char *set, const char *reset)
2389 {
2390         if (cnt <= 0)
2391                 return;
2392         strbuf_addstr(out, set);
2393         strbuf_addchars(out, ch, cnt);
2394         strbuf_addstr(out, reset);
2395 }
2396
2397 static void fill_print_name(struct diffstat_file *file)
2398 {
2399         struct strbuf pname = STRBUF_INIT;
2400
2401         if (file->print_name)
2402                 return;
2403
2404         if (file->is_renamed)
2405                 pprint_rename(&pname, file->from_name, file->name);
2406         else
2407                 quote_c_style(file->name, &pname, NULL, 0);
2408
2409         if (file->comments)
2410                 strbuf_addf(&pname, " (%s)", file->comments);
2411
2412         file->print_name = strbuf_detach(&pname, NULL);
2413 }
2414
2415 static void print_stat_summary_inserts_deletes(struct diff_options *options,
2416                 int files, int insertions, int deletions)
2417 {
2418         struct strbuf sb = STRBUF_INIT;
2419
2420         if (!files) {
2421                 assert(insertions == 0 && deletions == 0);
2422                 emit_diff_symbol(options, DIFF_SYMBOL_STATS_SUMMARY_NO_FILES,
2423                                  NULL, 0, 0);
2424                 return;
2425         }
2426
2427         strbuf_addf(&sb,
2428                     (files == 1) ? " %d file changed" : " %d files changed",
2429                     files);
2430
2431         /*
2432          * For binary diff, the caller may want to print "x files
2433          * changed" with insertions == 0 && deletions == 0.
2434          *
2435          * Not omitting "0 insertions(+), 0 deletions(-)" in this case
2436          * is probably less confusing (i.e skip over "2 files changed
2437          * but nothing about added/removed lines? Is this a bug in Git?").
2438          */
2439         if (insertions || deletions == 0) {
2440                 strbuf_addf(&sb,
2441                             (insertions == 1) ? ", %d insertion(+)" : ", %d insertions(+)",
2442                             insertions);
2443         }
2444
2445         if (deletions || insertions == 0) {
2446                 strbuf_addf(&sb,
2447                             (deletions == 1) ? ", %d deletion(-)" : ", %d deletions(-)",
2448                             deletions);
2449         }
2450         strbuf_addch(&sb, '\n');
2451         emit_diff_symbol(options, DIFF_SYMBOL_STATS_SUMMARY_INSERTS_DELETES,
2452                          sb.buf, sb.len, 0);
2453         strbuf_release(&sb);
2454 }
2455
2456 void print_stat_summary(FILE *fp, int files,
2457                         int insertions, int deletions)
2458 {
2459         struct diff_options o;
2460         memset(&o, 0, sizeof(o));
2461         o.file = fp;
2462
2463         print_stat_summary_inserts_deletes(&o, files, insertions, deletions);
2464 }
2465
2466 static void show_stats(struct diffstat_t *data, struct diff_options *options)
2467 {
2468         int i, len, add, del, adds = 0, dels = 0;
2469         uintmax_t max_change = 0, max_len = 0;
2470         int total_files = data->nr, count;
2471         int width, name_width, graph_width, number_width = 0, bin_width = 0;
2472         const char *reset, *add_c, *del_c;
2473         int extra_shown = 0;
2474         const char *line_prefix = diff_line_prefix(options);
2475         struct strbuf out = STRBUF_INIT;
2476
2477         if (data->nr == 0)
2478                 return;
2479
2480         count = options->stat_count ? options->stat_count : data->nr;
2481
2482         reset = diff_get_color_opt(options, DIFF_RESET);
2483         add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
2484         del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
2485
2486         /*
2487          * Find the longest filename and max number of changes
2488          */
2489         for (i = 0; (i < count) && (i < data->nr); i++) {
2490                 struct diffstat_file *file = data->files[i];
2491                 uintmax_t change = file->added + file->deleted;
2492
2493                 if (!file->is_interesting && (change == 0)) {
2494                         count++; /* not shown == room for one more */
2495                         continue;
2496                 }
2497                 fill_print_name(file);
2498                 len = strlen(file->print_name);
2499                 if (max_len < len)
2500                         max_len = len;
2501
2502                 if (file->is_unmerged) {
2503                         /* "Unmerged" is 8 characters */
2504                         bin_width = bin_width < 8 ? 8 : bin_width;
2505                         continue;
2506                 }
2507                 if (file->is_binary) {
2508                         /* "Bin XXX -> YYY bytes" */
2509                         int w = 14 + decimal_width(file->added)
2510                                 + decimal_width(file->deleted);
2511                         bin_width = bin_width < w ? w : bin_width;
2512                         /* Display change counts aligned with "Bin" */
2513                         number_width = 3;
2514                         continue;
2515                 }
2516
2517                 if (max_change < change)
2518                         max_change = change;
2519         }
2520         count = i; /* where we can stop scanning in data->files[] */
2521
2522         /*
2523          * We have width = stat_width or term_columns() columns total.
2524          * We want a maximum of min(max_len, stat_name_width) for the name part.
2525          * We want a maximum of min(max_change, stat_graph_width) for the +- part.
2526          * We also need 1 for " " and 4 + decimal_width(max_change)
2527          * for " | NNNN " and one the empty column at the end, altogether
2528          * 6 + decimal_width(max_change).
2529          *
2530          * If there's not enough space, we will use the smaller of
2531          * stat_name_width (if set) and 5/8*width for the filename,
2532          * and the rest for constant elements + graph part, but no more
2533          * than stat_graph_width for the graph part.
2534          * (5/8 gives 50 for filename and 30 for the constant parts + graph
2535          * for the standard terminal size).
2536          *
2537          * In other words: stat_width limits the maximum width, and
2538          * stat_name_width fixes the maximum width of the filename,
2539          * and is also used to divide available columns if there
2540          * aren't enough.
2541          *
2542          * Binary files are displayed with "Bin XXX -> YYY bytes"
2543          * instead of the change count and graph. This part is treated
2544          * similarly to the graph part, except that it is not
2545          * "scaled". If total width is too small to accommodate the
2546          * guaranteed minimum width of the filename part and the
2547          * separators and this message, this message will "overflow"
2548          * making the line longer than the maximum width.
2549          */
2550
2551         if (options->stat_width == -1)
2552                 width = term_columns() - strlen(line_prefix);
2553         else
2554                 width = options->stat_width ? options->stat_width : 80;
2555         number_width = decimal_width(max_change) > number_width ?
2556                 decimal_width(max_change) : number_width;
2557
2558         if (options->stat_graph_width == -1)
2559                 options->stat_graph_width = diff_stat_graph_width;
2560
2561         /*
2562          * Guarantee 3/8*16==6 for the graph part
2563          * and 5/8*16==10 for the filename part
2564          */
2565         if (width < 16 + 6 + number_width)
2566                 width = 16 + 6 + number_width;
2567
2568         /*
2569          * First assign sizes that are wanted, ignoring available width.
2570          * strlen("Bin XXX -> YYY bytes") == bin_width, and the part
2571          * starting from "XXX" should fit in graph_width.
2572          */
2573         graph_width = max_change + 4 > bin_width ? max_change : bin_width - 4;
2574         if (options->stat_graph_width &&
2575             options->stat_graph_width < graph_width)
2576                 graph_width = options->stat_graph_width;
2577
2578         name_width = (options->stat_name_width > 0 &&
2579                       options->stat_name_width < max_len) ?
2580                 options->stat_name_width : max_len;
2581
2582         /*
2583          * Adjust adjustable widths not to exceed maximum width
2584          */
2585         if (name_width + number_width + 6 + graph_width > width) {
2586                 if (graph_width > width * 3/8 - number_width - 6) {
2587                         graph_width = width * 3/8 - number_width - 6;
2588                         if (graph_width < 6)
2589                                 graph_width = 6;
2590                 }
2591
2592                 if (options->stat_graph_width &&
2593                     graph_width > options->stat_graph_width)
2594                         graph_width = options->stat_graph_width;
2595                 if (name_width > width - number_width - 6 - graph_width)
2596                         name_width = width - number_width - 6 - graph_width;
2597                 else
2598                         graph_width = width - number_width - 6 - name_width;
2599         }
2600
2601         /*
2602          * From here name_width is the width of the name area,
2603          * and graph_width is the width of the graph area.
2604          * max_change is used to scale graph properly.
2605          */
2606         for (i = 0; i < count; i++) {
2607                 const char *prefix = "";
2608                 struct diffstat_file *file = data->files[i];
2609                 char *name = file->print_name;
2610                 uintmax_t added = file->added;
2611                 uintmax_t deleted = file->deleted;
2612                 int name_len;
2613
2614                 if (!file->is_interesting && (added + deleted == 0))
2615                         continue;
2616
2617                 /*
2618                  * "scale" the filename
2619                  */
2620                 len = name_width;
2621                 name_len = strlen(name);
2622                 if (name_width < name_len) {
2623                         char *slash;
2624                         prefix = "...";
2625                         len -= 3;
2626                         name += name_len - len;
2627                         slash = strchr(name, '/');
2628                         if (slash)
2629                                 name = slash;
2630                 }
2631
2632                 if (file->is_binary) {
2633                         strbuf_addf(&out, " %s%-*s |", prefix, len, name);
2634                         strbuf_addf(&out, " %*s", number_width, "Bin");
2635                         if (!added && !deleted) {
2636                                 strbuf_addch(&out, '\n');
2637                                 emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2638                                                  out.buf, out.len, 0);
2639                                 strbuf_reset(&out);
2640                                 continue;
2641                         }
2642                         strbuf_addf(&out, " %s%"PRIuMAX"%s",
2643                                 del_c, deleted, reset);
2644                         strbuf_addstr(&out, " -> ");
2645                         strbuf_addf(&out, "%s%"PRIuMAX"%s",
2646                                 add_c, added, reset);
2647                         strbuf_addstr(&out, " bytes\n");
2648                         emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2649                                          out.buf, out.len, 0);
2650                         strbuf_reset(&out);
2651                         continue;
2652                 }
2653                 else if (file->is_unmerged) {
2654                         strbuf_addf(&out, " %s%-*s |", prefix, len, name);
2655                         strbuf_addstr(&out, " Unmerged\n");
2656                         emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2657                                          out.buf, out.len, 0);
2658                         strbuf_reset(&out);
2659                         continue;
2660                 }
2661
2662                 /*
2663                  * scale the add/delete
2664                  */
2665                 add = added;
2666                 del = deleted;
2667
2668                 if (graph_width <= max_change) {
2669                         int total = scale_linear(add + del, graph_width, max_change);
2670                         if (total < 2 && add && del)
2671                                 /* width >= 2 due to the sanity check */
2672                                 total = 2;
2673                         if (add < del) {
2674                                 add = scale_linear(add, graph_width, max_change);
2675                                 del = total - add;
2676                         } else {
2677                                 del = scale_linear(del, graph_width, max_change);
2678                                 add = total - del;
2679                         }
2680                 }
2681                 strbuf_addf(&out, " %s%-*s |", prefix, len, name);
2682                 strbuf_addf(&out, " %*"PRIuMAX"%s",
2683                         number_width, added + deleted,
2684                         added + deleted ? " " : "");
2685                 show_graph(&out, '+', add, add_c, reset);
2686                 show_graph(&out, '-', del, del_c, reset);
2687                 strbuf_addch(&out, '\n');
2688                 emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2689                                  out.buf, out.len, 0);
2690                 strbuf_reset(&out);
2691         }
2692
2693         for (i = 0; i < data->nr; i++) {
2694                 struct diffstat_file *file = data->files[i];
2695                 uintmax_t added = file->added;
2696                 uintmax_t deleted = file->deleted;
2697
2698                 if (file->is_unmerged ||
2699                     (!file->is_interesting && (added + deleted == 0))) {
2700                         total_files--;
2701                         continue;
2702                 }
2703
2704                 if (!file->is_binary) {
2705                         adds += added;
2706                         dels += deleted;
2707                 }
2708                 if (i < count)
2709                         continue;
2710                 if (!extra_shown)
2711                         emit_diff_symbol(options,
2712                                          DIFF_SYMBOL_STATS_SUMMARY_ABBREV,
2713                                          NULL, 0, 0);
2714                 extra_shown = 1;
2715         }
2716
2717         print_stat_summary_inserts_deletes(options, total_files, adds, dels);
2718         strbuf_release(&out);
2719 }
2720
2721 static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
2722 {
2723         int i, adds = 0, dels = 0, total_files = data->nr;
2724
2725         if (data->nr == 0)
2726                 return;
2727
2728         for (i = 0; i < data->nr; i++) {
2729                 int added = data->files[i]->added;
2730                 int deleted = data->files[i]->deleted;
2731
2732                 if (data->files[i]->is_unmerged ||
2733                     (!data->files[i]->is_interesting && (added + deleted == 0))) {
2734                         total_files--;
2735                 } else if (!data->files[i]->is_binary) { /* don't count bytes */
2736                         adds += added;
2737                         dels += deleted;
2738                 }
2739         }
2740         print_stat_summary_inserts_deletes(options, total_files, adds, dels);
2741 }
2742
2743 static void show_numstat(struct diffstat_t *data, struct diff_options *options)
2744 {
2745         int i;
2746
2747         if (data->nr == 0)
2748                 return;
2749
2750         for (i = 0; i < data->nr; i++) {
2751                 struct diffstat_file *file = data->files[i];
2752
2753                 fprintf(options->file, "%s", diff_line_prefix(options));
2754
2755                 if (file->is_binary)
2756                         fprintf(options->file, "-\t-\t");
2757                 else
2758                         fprintf(options->file,
2759                                 "%"PRIuMAX"\t%"PRIuMAX"\t",
2760                                 file->added, file->deleted);
2761                 if (options->line_termination) {
2762                         fill_print_name(file);
2763                         if (!file->is_renamed)
2764                                 write_name_quoted(file->name, options->file,
2765                                                   options->line_termination);
2766                         else {
2767                                 fputs(file->print_name, options->file);
2768                                 putc(options->line_termination, options->file);
2769                         }
2770                 } else {
2771                         if (file->is_renamed) {
2772                                 putc('\0', options->file);
2773                                 write_name_quoted(file->from_name, options->file, '\0');
2774                         }
2775                         write_name_quoted(file->name, options->file, '\0');
2776                 }
2777         }
2778 }
2779
2780 struct dirstat_file {
2781         const char *name;
2782         unsigned long changed;
2783 };
2784
2785 struct dirstat_dir {
2786         struct dirstat_file *files;
2787         int alloc, nr, permille, cumulative;
2788 };
2789
2790 static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
2791                 unsigned long changed, const char *base, int baselen)
2792 {
2793         unsigned long sum_changes = 0;
2794         unsigned int sources = 0;
2795         const char *line_prefix = diff_line_prefix(opt);
2796
2797         while (dir->nr) {
2798                 struct dirstat_file *f = dir->files;
2799                 int namelen = strlen(f->name);
2800                 unsigned long changes;
2801                 char *slash;
2802
2803                 if (namelen < baselen)
2804                         break;
2805                 if (memcmp(f->name, base, baselen))
2806                         break;
2807                 slash = strchr(f->name + baselen, '/');
2808                 if (slash) {
2809                         int newbaselen = slash + 1 - f->name;
2810                         changes = gather_dirstat(opt, dir, changed, f->name, newbaselen);
2811                         sources++;
2812                 } else {
2813                         changes = f->changed;
2814                         dir->files++;
2815                         dir->nr--;
2816                         sources += 2;
2817                 }
2818                 sum_changes += changes;
2819         }
2820
2821         /*
2822          * We don't report dirstat's for
2823          *  - the top level
2824          *  - or cases where everything came from a single directory
2825          *    under this directory (sources == 1).
2826          */
2827         if (baselen && sources != 1) {
2828                 if (sum_changes) {
2829                         int permille = sum_changes * 1000 / changed;
2830                         if (permille >= dir->permille) {
2831                                 fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
2832                                         permille / 10, permille % 10, baselen, base);
2833                                 if (!dir->cumulative)
2834                                         return 0;
2835                         }
2836                 }
2837         }
2838         return sum_changes;
2839 }
2840
2841 static int dirstat_compare(const void *_a, const void *_b)
2842 {
2843         const struct dirstat_file *a = _a;
2844         const struct dirstat_file *b = _b;
2845         return strcmp(a->name, b->name);
2846 }
2847
2848 static void show_dirstat(struct diff_options *options)
2849 {
2850         int i;
2851         unsigned long changed;
2852         struct dirstat_dir dir;
2853         struct diff_queue_struct *q = &diff_queued_diff;
2854
2855         dir.files = NULL;
2856         dir.alloc = 0;
2857         dir.nr = 0;
2858         dir.permille = options->dirstat_permille;
2859         dir.cumulative = options->flags.dirstat_cumulative;
2860
2861         changed = 0;
2862         for (i = 0; i < q->nr; i++) {
2863                 struct diff_filepair *p = q->queue[i];
2864                 const char *name;
2865                 unsigned long copied, added, damage;
2866                 int content_changed;
2867
2868                 name = p->two->path ? p->two->path : p->one->path;
2869
2870                 if (p->one->oid_valid && p->two->oid_valid)
2871                         content_changed = oidcmp(&p->one->oid, &p->two->oid);
2872                 else
2873                         content_changed = 1;
2874
2875                 if (!content_changed) {
2876                         /*
2877                          * The SHA1 has not changed, so pre-/post-content is
2878                          * identical. We can therefore skip looking at the
2879                          * file contents altogether.
2880                          */
2881                         damage = 0;
2882                         goto found_damage;
2883                 }
2884
2885                 if (options->flags.dirstat_by_file) {
2886                         /*
2887                          * In --dirstat-by-file mode, we don't really need to
2888                          * look at the actual file contents at all.
2889                          * The fact that the SHA1 changed is enough for us to
2890                          * add this file to the list of results
2891                          * (with each file contributing equal damage).
2892                          */
2893                         damage = 1;
2894                         goto found_damage;
2895                 }
2896
2897                 if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
2898                         diff_populate_filespec(p->one, 0);
2899                         diff_populate_filespec(p->two, 0);
2900                         diffcore_count_changes(p->one, p->two, NULL, NULL,
2901                                                &copied, &added);
2902                         diff_free_filespec_data(p->one);
2903                         diff_free_filespec_data(p->two);
2904                 } else if (DIFF_FILE_VALID(p->one)) {
2905                         diff_populate_filespec(p->one, CHECK_SIZE_ONLY);
2906                         copied = added = 0;
2907                         diff_free_filespec_data(p->one);
2908                 } else if (DIFF_FILE_VALID(p->two)) {
2909                         diff_populate_filespec(p->two, CHECK_SIZE_ONLY);
2910                         copied = 0;
2911                         added = p->two->size;
2912                         diff_free_filespec_data(p->two);
2913                 } else
2914                         continue;
2915
2916                 /*
2917                  * Original minus copied is the removed material,
2918                  * added is the new material.  They are both damages
2919                  * made to the preimage.
2920                  * If the resulting damage is zero, we know that
2921                  * diffcore_count_changes() considers the two entries to
2922                  * be identical, but since content_changed is true, we
2923                  * know that there must have been _some_ kind of change,
2924                  * so we force all entries to have damage > 0.
2925                  */
2926                 damage = (p->one->size - copied) + added;
2927                 if (!damage)
2928                         damage = 1;
2929
2930 found_damage:
2931                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
2932                 dir.files[dir.nr].name = name;
2933                 dir.files[dir.nr].changed = damage;
2934                 changed += damage;
2935                 dir.nr++;
2936         }
2937
2938         /* This can happen even with many files, if everything was renames */
2939         if (!changed)
2940                 return;
2941
2942         /* Show all directories with more than x% of the changes */
2943         QSORT(dir.files, dir.nr, dirstat_compare);
2944         gather_dirstat(options, &dir, changed, "", 0);
2945 }
2946
2947 static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
2948 {
2949         int i;
2950         unsigned long changed;
2951         struct dirstat_dir dir;
2952
2953         if (data->nr == 0)
2954                 return;
2955
2956         dir.files = NULL;
2957         dir.alloc = 0;
2958         dir.nr = 0;
2959         dir.permille = options->dirstat_permille;
2960         dir.cumulative = options->flags.dirstat_cumulative;
2961
2962         changed = 0;
2963         for (i = 0; i < data->nr; i++) {
2964                 struct diffstat_file *file = data->files[i];
2965                 unsigned long damage = file->added + file->deleted;
2966                 if (file->is_binary)
2967                         /*
2968                          * binary files counts bytes, not lines. Must find some
2969                          * way to normalize binary bytes vs. textual lines.
2970                          * The following heuristic assumes that there are 64
2971                          * bytes per "line".
2972                          * This is stupid and ugly, but very cheap...
2973                          */
2974                         damage = DIV_ROUND_UP(damage, 64);
2975                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
2976                 dir.files[dir.nr].name = file->name;
2977                 dir.files[dir.nr].changed = damage;
2978                 changed += damage;
2979                 dir.nr++;
2980         }
2981
2982         /* This can happen even with many files, if everything was renames */
2983         if (!changed)
2984                 return;
2985
2986         /* Show all directories with more than x% of the changes */
2987         QSORT(dir.files, dir.nr, dirstat_compare);
2988         gather_dirstat(options, &dir, changed, "", 0);
2989 }
2990
2991 static void free_diffstat_info(struct diffstat_t *diffstat)
2992 {
2993         int i;
2994         for (i = 0; i < diffstat->nr; i++) {
2995                 struct diffstat_file *f = diffstat->files[i];
2996                 free(f->print_name);
2997                 free(f->name);
2998                 free(f->from_name);
2999                 free(f);
3000         }
3001         free(diffstat->files);
3002 }
3003
3004 struct checkdiff_t {
3005         const char *filename;
3006         int lineno;
3007         int conflict_marker_size;
3008         struct diff_options *o;
3009         unsigned ws_rule;
3010         unsigned status;
3011 };
3012
3013 static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
3014 {
3015         char firstchar;
3016         int cnt;
3017
3018         if (len < marker_size + 1)
3019                 return 0;
3020         firstchar = line[0];
3021         switch (firstchar) {
3022         case '=': case '>': case '<': case '|':
3023                 break;
3024         default:
3025                 return 0;
3026         }
3027         for (cnt = 1; cnt < marker_size; cnt++)
3028                 if (line[cnt] != firstchar)
3029                         return 0;
3030         /* line[1] thru line[marker_size-1] are same as firstchar */
3031         if (len < marker_size + 1 || !isspace(line[marker_size]))
3032                 return 0;
3033         return 1;
3034 }
3035
3036 static void checkdiff_consume(void *priv, char *line, unsigned long len)
3037 {
3038         struct checkdiff_t *data = priv;
3039         int marker_size = data->conflict_marker_size;
3040         const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
3041         const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
3042         const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
3043         char *err;
3044         const char *line_prefix;
3045
3046         assert(data->o);
3047         line_prefix = diff_line_prefix(data->o);
3048
3049         if (line[0] == '+') {
3050                 unsigned bad;
3051                 data->lineno++;
3052                 if (is_conflict_marker(line + 1, marker_size, len - 1)) {
3053                         data->status |= 1;
3054                         fprintf(data->o->file,
3055                                 "%s%s:%d: leftover conflict marker\n",
3056                                 line_prefix, data->filename, data->lineno);
3057                 }
3058                 bad = ws_check(line + 1, len - 1, data->ws_rule);
3059                 if (!bad)
3060                         return;
3061                 data->status |= bad;
3062                 err = whitespace_error_string(bad);
3063                 fprintf(data->o->file, "%s%s:%d: %s.\n",
3064                         line_prefix, data->filename, data->lineno, err);
3065                 free(err);
3066                 emit_line(data->o, set, reset, line, 1);
3067                 ws_check_emit(line + 1, len - 1, data->ws_rule,
3068                               data->o->file, set, reset, ws);
3069         } else if (line[0] == ' ') {
3070                 data->lineno++;
3071         } else if (line[0] == '@') {
3072                 char *plus = strchr(line, '+');
3073                 if (plus)
3074                         data->lineno = strtol(plus, NULL, 10) - 1;
3075                 else
3076                         die("invalid diff");
3077         }
3078 }
3079
3080 static unsigned char *deflate_it(char *data,
3081                                  unsigned long size,
3082                                  unsigned long *result_size)
3083 {
3084         int bound;
3085         unsigned char *deflated;
3086         git_zstream stream;
3087
3088         git_deflate_init(&stream, zlib_compression_level);
3089         bound = git_deflate_bound(&stream, size);
3090         deflated = xmalloc(bound);
3091         stream.next_out = deflated;
3092         stream.avail_out = bound;
3093
3094         stream.next_in = (unsigned char *)data;
3095         stream.avail_in = size;
3096         while (git_deflate(&stream, Z_FINISH) == Z_OK)
3097                 ; /* nothing */
3098         git_deflate_end(&stream);
3099         *result_size = stream.total_out;
3100         return deflated;
3101 }
3102
3103 static void emit_binary_diff_body(struct diff_options *o,
3104                                   mmfile_t *one, mmfile_t *two)
3105 {
3106         void *cp;
3107         void *delta;
3108         void *deflated;
3109         void *data;
3110         unsigned long orig_size;
3111         unsigned long delta_size;
3112         unsigned long deflate_size;
3113         unsigned long data_size;
3114
3115         /* We could do deflated delta, or we could do just deflated two,
3116          * whichever is smaller.
3117          */
3118         delta = NULL;
3119         deflated = deflate_it(two->ptr, two->size, &deflate_size);
3120         if (one->size && two->size) {
3121                 delta = diff_delta(one->ptr, one->size,
3122                                    two->ptr, two->size,
3123                                    &delta_size, deflate_size);
3124                 if (delta) {
3125                         void *to_free = delta;
3126                         orig_size = delta_size;
3127                         delta = deflate_it(delta, delta_size, &delta_size);
3128                         free(to_free);
3129                 }
3130         }
3131
3132         if (delta && delta_size < deflate_size) {
3133                 char *s = xstrfmt("%lu", orig_size);
3134                 emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_HEADER_DELTA,
3135                                  s, strlen(s), 0);
3136                 free(s);
3137                 free(deflated);
3138                 data = delta;
3139                 data_size = delta_size;
3140         } else {
3141                 char *s = xstrfmt("%lu", two->size);
3142                 emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_HEADER_LITERAL,
3143                                  s, strlen(s), 0);
3144                 free(s);
3145                 free(delta);
3146                 data = deflated;
3147                 data_size = deflate_size;
3148         }
3149
3150         /* emit data encoded in base85 */
3151         cp = data;
3152         while (data_size) {
3153                 int len;
3154                 int bytes = (52 < data_size) ? 52 : data_size;
3155                 char line[71];
3156                 data_size -= bytes;
3157                 if (bytes <= 26)
3158                         line[0] = bytes + 'A' - 1;
3159                 else
3160                         line[0] = bytes - 26 + 'a' - 1;
3161                 encode_85(line + 1, cp, bytes);
3162                 cp = (char *) cp + bytes;
3163
3164                 len = strlen(line);
3165                 line[len++] = '\n';
3166                 line[len] = '\0';
3167
3168                 emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_BODY,
3169                                  line, len, 0);
3170         }
3171         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_FOOTER, NULL, 0, 0);
3172         free(data);
3173 }
3174
3175 static void emit_binary_diff(struct diff_options *o,
3176                              mmfile_t *one, mmfile_t *two)
3177 {
3178         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_HEADER, NULL, 0, 0);
3179         emit_binary_diff_body(o, one, two);
3180         emit_binary_diff_body(o, two, one);
3181 }
3182
3183 int diff_filespec_is_binary(struct diff_filespec *one)
3184 {
3185         if (one->is_binary == -1) {
3186                 diff_filespec_load_driver(one);
3187                 if (one->driver->binary != -1)
3188                         one->is_binary = one->driver->binary;
3189                 else {
3190                         if (!one->data && DIFF_FILE_VALID(one))
3191                                 diff_populate_filespec(one, CHECK_BINARY);
3192                         if (one->is_binary == -1 && one->data)
3193                                 one->is_binary = buffer_is_binary(one->data,
3194                                                 one->size);
3195                         if (one->is_binary == -1)
3196                                 one->is_binary = 0;
3197                 }
3198         }
3199         return one->is_binary;
3200 }
3201
3202 static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
3203 {
3204         diff_filespec_load_driver(one);
3205         return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
3206 }
3207
3208 void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
3209 {
3210         if (!options->a_prefix)
3211                 options->a_prefix = a;
3212         if (!options->b_prefix)
3213                 options->b_prefix = b;
3214 }
3215
3216 struct userdiff_driver *get_textconv(struct diff_filespec *one)
3217 {
3218         if (!DIFF_FILE_VALID(one))
3219                 return NULL;
3220
3221         diff_filespec_load_driver(one);
3222         return userdiff_get_textconv(one->driver);
3223 }
3224
3225 static void builtin_diff(const char *name_a,
3226                          const char *name_b,
3227                          struct diff_filespec *one,
3228                          struct diff_filespec *two,
3229                          const char *xfrm_msg,
3230                          int must_show_header,
3231                          struct diff_options *o,
3232                          int complete_rewrite)
3233 {
3234         mmfile_t mf1, mf2;
3235         const char *lbl[2];
3236         char *a_one, *b_two;
3237         const char *meta = diff_get_color_opt(o, DIFF_METAINFO);
3238         const char *reset = diff_get_color_opt(o, DIFF_RESET);
3239         const char *a_prefix, *b_prefix;
3240         struct userdiff_driver *textconv_one = NULL;
3241         struct userdiff_driver *textconv_two = NULL;
3242         struct strbuf header = STRBUF_INIT;
3243         const char *line_prefix = diff_line_prefix(o);
3244
3245         diff_set_mnemonic_prefix(o, "a/", "b/");
3246         if (o->flags.reverse_diff) {
3247                 a_prefix = o->b_prefix;
3248                 b_prefix = o->a_prefix;
3249         } else {
3250                 a_prefix = o->a_prefix;
3251                 b_prefix = o->b_prefix;
3252         }
3253
3254         if (o->submodule_format == DIFF_SUBMODULE_LOG &&
3255             (!one->mode || S_ISGITLINK(one->mode)) &&
3256             (!two->mode || S_ISGITLINK(two->mode))) {
3257                 show_submodule_summary(o, one->path ? one->path : two->path,
3258                                 &one->oid, &two->oid,
3259                                 two->dirty_submodule);
3260                 return;
3261         } else if (o->submodule_format == DIFF_SUBMODULE_INLINE_DIFF &&
3262                    (!one->mode || S_ISGITLINK(one->mode)) &&
3263                    (!two->mode || S_ISGITLINK(two->mode))) {
3264                 show_submodule_inline_diff(o, one->path ? one->path : two->path,
3265                                 &one->oid, &two->oid,
3266                                 two->dirty_submodule);
3267                 return;
3268         }
3269
3270         if (o->flags.allow_textconv) {
3271                 textconv_one = get_textconv(one);
3272                 textconv_two = get_textconv(two);
3273         }
3274
3275         /* Never use a non-valid filename anywhere if at all possible */
3276         name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
3277         name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
3278
3279         a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
3280         b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
3281         lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
3282         lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
3283         strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, meta, a_one, b_two, reset);
3284         if (lbl[0][0] == '/') {
3285                 /* /dev/null */
3286                 strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, meta, two->mode, reset);
3287                 if (xfrm_msg)
3288                         strbuf_addstr(&header, xfrm_msg);
3289                 must_show_header = 1;
3290         }
3291         else if (lbl[1][0] == '/') {
3292                 strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, meta, one->mode, reset);
3293                 if (xfrm_msg)
3294                         strbuf_addstr(&header, xfrm_msg);
3295                 must_show_header = 1;
3296         }
3297         else {
3298                 if (one->mode != two->mode) {
3299                         strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, meta, one->mode, reset);
3300                         strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, meta, two->mode, reset);
3301                         must_show_header = 1;
3302                 }
3303                 if (xfrm_msg)
3304                         strbuf_addstr(&header, xfrm_msg);
3305
3306                 /*
3307                  * we do not run diff between different kind
3308                  * of objects.
3309                  */
3310                 if ((one->mode ^ two->mode) & S_IFMT)
3311                         goto free_ab_and_return;
3312                 if (complete_rewrite &&
3313                     (textconv_one || !diff_filespec_is_binary(one)) &&
3314                     (textconv_two || !diff_filespec_is_binary(two))) {
3315                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3316                                          header.buf, header.len, 0);
3317                         strbuf_reset(&header);
3318                         emit_rewrite_diff(name_a, name_b, one, two,
3319                                                 textconv_one, textconv_two, o);
3320                         o->found_changes = 1;
3321                         goto free_ab_and_return;
3322                 }
3323         }
3324
3325         if (o->irreversible_delete && lbl[1][0] == '/') {
3326                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER, header.buf,
3327                                  header.len, 0);
3328                 strbuf_reset(&header);
3329                 goto free_ab_and_return;
3330         } else if (!o->flags.text &&
3331             ( (!textconv_one && diff_filespec_is_binary(one)) ||
3332               (!textconv_two && diff_filespec_is_binary(two)) )) {
3333                 struct strbuf sb = STRBUF_INIT;
3334                 if (!one->data && !two->data &&
3335                     S_ISREG(one->mode) && S_ISREG(two->mode) &&
3336                     !o->flags.binary) {
3337                         if (!oidcmp(&one->oid, &two->oid)) {
3338                                 if (must_show_header)
3339                                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3340                                                          header.buf, header.len,
3341                                                          0);
3342                                 goto free_ab_and_return;
3343                         }
3344                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3345                                          header.buf, header.len, 0);
3346                         strbuf_addf(&sb, "%sBinary files %s and %s differ\n",
3347                                     diff_line_prefix(o), lbl[0], lbl[1]);
3348                         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_FILES,
3349                                          sb.buf, sb.len, 0);
3350                         strbuf_release(&sb);
3351                         goto free_ab_and_return;
3352                 }
3353                 if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
3354                         die("unable to read files to diff");
3355                 /* Quite common confusing case */
3356                 if (mf1.size == mf2.size &&
3357                     !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
3358                         if (must_show_header)
3359                                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3360                                                  header.buf, header.len, 0);
3361                         goto free_ab_and_return;
3362                 }
3363                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER, header.buf, header.len, 0);
3364                 strbuf_reset(&header);
3365                 if (o->flags.binary)
3366                         emit_binary_diff(o, &mf1, &mf2);
3367                 else {
3368                         strbuf_addf(&sb, "%sBinary files %s and %s differ\n",
3369                                     diff_line_prefix(o), lbl[0], lbl[1]);
3370                         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_FILES,
3371                                          sb.buf, sb.len, 0);
3372                         strbuf_release(&sb);
3373                 }
3374                 o->found_changes = 1;
3375         } else {
3376                 /* Crazy xdl interfaces.. */
3377                 const char *diffopts = getenv("GIT_DIFF_OPTS");
3378                 const char *v;
3379                 xpparam_t xpp;
3380                 xdemitconf_t xecfg;
3381                 struct emit_callback ecbdata;
3382                 const struct userdiff_funcname *pe;
3383
3384                 if (must_show_header) {
3385                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3386                                          header.buf, header.len, 0);
3387                         strbuf_reset(&header);
3388                 }
3389
3390                 mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
3391                 mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
3392
3393                 pe = diff_funcname_pattern(one);
3394                 if (!pe)
3395                         pe = diff_funcname_pattern(two);
3396
3397                 memset(&xpp, 0, sizeof(xpp));
3398                 memset(&xecfg, 0, sizeof(xecfg));
3399                 memset(&ecbdata, 0, sizeof(ecbdata));
3400                 ecbdata.label_path = lbl;
3401                 ecbdata.color_diff = want_color(o->use_color);
3402                 ecbdata.ws_rule = whitespace_rule(name_b);
3403                 if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
3404                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
3405                 ecbdata.opt = o;
3406                 ecbdata.header = header.len ? &header : NULL;
3407                 xpp.flags = o->xdl_opts;
3408                 xpp.anchors = o->anchors;
3409                 xpp.anchors_nr = o->anchors_nr;
3410                 xecfg.ctxlen = o->context;
3411                 xecfg.interhunkctxlen = o->interhunkcontext;
3412                 xecfg.flags = XDL_EMIT_FUNCNAMES;
3413                 if (o->flags.funccontext)
3414                         xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
3415                 if (pe)
3416                         xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
3417                 if (!diffopts)
3418                         ;
3419                 else if (skip_prefix(diffopts, "--unified=", &v))
3420                         xecfg.ctxlen = strtoul(v, NULL, 10);
3421                 else if (skip_prefix(diffopts, "-u", &v))
3422                         xecfg.ctxlen = strtoul(v, NULL, 10);
3423                 if (o->word_diff)
3424                         init_diff_words_data(&ecbdata, o, one, two);
3425                 if (xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
3426                                   &xpp, &xecfg))
3427                         die("unable to generate diff for %s", one->path);
3428                 if (o->word_diff)
3429                         free_diff_words_data(&ecbdata);
3430                 if (textconv_one)
3431                         free(mf1.ptr);
3432                 if (textconv_two)
3433                         free(mf2.ptr);
3434                 xdiff_clear_find_func(&xecfg);
3435         }
3436
3437  free_ab_and_return:
3438         strbuf_release(&header);
3439         diff_free_filespec_data(one);
3440         diff_free_filespec_data(two);
3441         free(a_one);
3442         free(b_two);
3443         return;
3444 }
3445
3446 static char *get_compact_summary(const struct diff_filepair *p, int is_renamed)
3447 {
3448         if (!is_renamed) {
3449                 if (p->status == DIFF_STATUS_ADDED) {
3450                         if (S_ISLNK(p->two->mode))
3451                                 return "new +l";
3452                         else if ((p->two->mode & 0777) == 0755)
3453                                 return "new +x";
3454                         else
3455                                 return "new";
3456                 } else if (p->status == DIFF_STATUS_DELETED)
3457                         return "gone";
3458         }
3459         if (S_ISLNK(p->one->mode) && !S_ISLNK(p->two->mode))
3460                 return "mode -l";
3461         else if (!S_ISLNK(p->one->mode) && S_ISLNK(p->two->mode))
3462                 return "mode +l";
3463         else if ((p->one->mode & 0777) == 0644 &&
3464                  (p->two->mode & 0777) == 0755)
3465                 return "mode +x";
3466         else if ((p->one->mode & 0777) == 0755 &&
3467                  (p->two->mode & 0777) == 0644)
3468                 return "mode -x";
3469         return NULL;
3470 }
3471
3472 static void builtin_diffstat(const char *name_a, const char *name_b,
3473                              struct diff_filespec *one,
3474                              struct diff_filespec *two,
3475                              struct diffstat_t *diffstat,
3476                              struct diff_options *o,
3477                              struct diff_filepair *p)
3478 {
3479         mmfile_t mf1, mf2;
3480         struct diffstat_file *data;
3481         int same_contents;
3482         int complete_rewrite = 0;
3483
3484         if (!DIFF_PAIR_UNMERGED(p)) {
3485                 if (p->status == DIFF_STATUS_MODIFIED && p->score)
3486                         complete_rewrite = 1;
3487         }
3488
3489         data = diffstat_add(diffstat, name_a, name_b);
3490         data->is_interesting = p->status != DIFF_STATUS_UNKNOWN;
3491         if (o->flags.stat_with_summary)
3492                 data->comments = get_compact_summary(p, data->is_renamed);
3493
3494         if (!one || !two) {
3495                 data->is_unmerged = 1;
3496                 return;
3497         }
3498
3499         same_contents = !oidcmp(&one->oid, &two->oid);
3500
3501         if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
3502                 data->is_binary = 1;
3503                 if (same_contents) {
3504                         data->added = 0;
3505                         data->deleted = 0;
3506                 } else {
3507                         data->added = diff_filespec_size(two);
3508                         data->deleted = diff_filespec_size(one);
3509                 }
3510         }
3511
3512         else if (complete_rewrite) {
3513                 diff_populate_filespec(one, 0);
3514                 diff_populate_filespec(two, 0);
3515                 data->deleted = count_lines(one->data, one->size);
3516                 data->added = count_lines(two->data, two->size);
3517         }
3518
3519         else if (!same_contents) {
3520                 /* Crazy xdl interfaces.. */
3521                 xpparam_t xpp;
3522                 xdemitconf_t xecfg;
3523
3524                 if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
3525                         die("unable to read files to diff");
3526
3527                 memset(&xpp, 0, sizeof(xpp));
3528                 memset(&xecfg, 0, sizeof(xecfg));
3529                 xpp.flags = o->xdl_opts;
3530                 xpp.anchors = o->anchors;
3531                 xpp.anchors_nr = o->anchors_nr;
3532                 xecfg.ctxlen = o->context;
3533                 xecfg.interhunkctxlen = o->interhunkcontext;
3534                 if (xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
3535                                   &xpp, &xecfg))
3536                         die("unable to generate diffstat for %s", one->path);
3537         }
3538
3539         diff_free_filespec_data(one);
3540         diff_free_filespec_data(two);
3541 }
3542
3543 static void builtin_checkdiff(const char *name_a, const char *name_b,
3544                               const char *attr_path,
3545                               struct diff_filespec *one,
3546                               struct diff_filespec *two,
3547                               struct diff_options *o)
3548 {
3549         mmfile_t mf1, mf2;
3550         struct checkdiff_t data;
3551
3552         if (!two)
3553                 return;
3554
3555         memset(&data, 0, sizeof(data));
3556         data.filename = name_b ? name_b : name_a;
3557         data.lineno = 0;
3558         data.o = o;
3559         data.ws_rule = whitespace_rule(attr_path);
3560         data.conflict_marker_size = ll_merge_marker_size(attr_path);
3561
3562         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
3563                 die("unable to read files to diff");
3564
3565         /*
3566          * All the other codepaths check both sides, but not checking
3567          * the "old" side here is deliberate.  We are checking the newly
3568          * introduced changes, and as long as the "new" side is text, we
3569          * can and should check what it introduces.
3570          */
3571         if (diff_filespec_is_binary(two))
3572                 goto free_and_return;
3573         else {
3574                 /* Crazy xdl interfaces.. */
3575                 xpparam_t xpp;
3576                 xdemitconf_t xecfg;
3577
3578                 memset(&xpp, 0, sizeof(xpp));
3579                 memset(&xecfg, 0, sizeof(xecfg));
3580                 xecfg.ctxlen = 1; /* at least one context line */
3581                 xpp.flags = 0;
3582                 if (xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
3583                                   &xpp, &xecfg))
3584                         die("unable to generate checkdiff for %s", one->path);
3585
3586                 if (data.ws_rule & WS_BLANK_AT_EOF) {
3587                         struct emit_callback ecbdata;
3588                         int blank_at_eof;
3589
3590                         ecbdata.ws_rule = data.ws_rule;
3591                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
3592                         blank_at_eof = ecbdata.blank_at_eof_in_postimage;
3593
3594                         if (blank_at_eof) {
3595                                 static char *err;
3596                                 if (!err)
3597                                         err = whitespace_error_string(WS_BLANK_AT_EOF);
3598                                 fprintf(o->file, "%s:%d: %s.\n",
3599                                         data.filename, blank_at_eof, err);
3600                                 data.status = 1; /* report errors */
3601                         }
3602                 }
3603         }
3604  free_and_return:
3605         diff_free_filespec_data(one);
3606         diff_free_filespec_data(two);
3607         if (data.status)
3608                 o->flags.check_failed = 1;
3609 }
3610
3611 struct diff_filespec *alloc_filespec(const char *path)
3612 {
3613         struct diff_filespec *spec;
3614
3615         FLEXPTR_ALLOC_STR(spec, path, path);
3616         spec->count = 1;
3617         spec->is_binary = -1;
3618         return spec;
3619 }
3620
3621 void free_filespec(struct diff_filespec *spec)
3622 {
3623         if (!--spec->count) {
3624                 diff_free_filespec_data(spec);
3625                 free(spec);
3626         }
3627 }
3628
3629 void fill_filespec(struct diff_filespec *spec, const struct object_id *oid,
3630                    int oid_valid, unsigned short mode)
3631 {
3632         if (mode) {
3633                 spec->mode = canon_mode(mode);
3634                 oidcpy(&spec->oid, oid);
3635                 spec->oid_valid = oid_valid;
3636         }
3637 }
3638
3639 /*
3640  * Given a name and sha1 pair, if the index tells us the file in
3641  * the work tree has that object contents, return true, so that
3642  * prepare_temp_file() does not have to inflate and extract.
3643  */
3644 static int reuse_worktree_file(const char *name, const struct object_id *oid, int want_file)
3645 {
3646         const struct cache_entry *ce;
3647         struct stat st;
3648         int pos, len;
3649
3650         /*
3651          * We do not read the cache ourselves here, because the
3652          * benchmark with my previous version that always reads cache
3653          * shows that it makes things worse for diff-tree comparing
3654          * two linux-2.6 kernel trees in an already checked out work
3655          * tree.  This is because most diff-tree comparisons deal with
3656          * only a small number of files, while reading the cache is
3657          * expensive for a large project, and its cost outweighs the
3658          * savings we get by not inflating the object to a temporary
3659          * file.  Practically, this code only helps when we are used
3660          * by diff-cache --cached, which does read the cache before
3661          * calling us.
3662          */
3663         if (!active_cache)
3664                 return 0;
3665
3666         /* We want to avoid the working directory if our caller
3667          * doesn't need the data in a normal file, this system
3668          * is rather slow with its stat/open/mmap/close syscalls,
3669          * and the object is contained in a pack file.  The pack
3670          * is probably already open and will be faster to obtain
3671          * the data through than the working directory.  Loose
3672          * objects however would tend to be slower as they need
3673          * to be individually opened and inflated.
3674          */
3675         if (!FAST_WORKING_DIRECTORY && !want_file && has_object_pack(oid))
3676                 return 0;
3677
3678         /*
3679          * Similarly, if we'd have to convert the file contents anyway, that
3680          * makes the optimization not worthwhile.
3681          */
3682         if (!want_file && would_convert_to_git(&the_index, name))
3683                 return 0;
3684
3685         len = strlen(name);
3686         pos = cache_name_pos(name, len);
3687         if (pos < 0)
3688                 return 0;
3689         ce = active_cache[pos];
3690
3691         /*
3692          * This is not the sha1 we are looking for, or
3693          * unreusable because it is not a regular file.
3694          */
3695         if (oidcmp(oid, &ce->oid) || !S_ISREG(ce->ce_mode))
3696                 return 0;
3697
3698         /*
3699          * If ce is marked as "assume unchanged", there is no
3700          * guarantee that work tree matches what we are looking for.
3701          */
3702         if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
3703                 return 0;
3704
3705         /*
3706          * If ce matches the file in the work tree, we can reuse it.
3707          */
3708         if (ce_uptodate(ce) ||
3709             (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
3710                 return 1;
3711
3712         return 0;
3713 }
3714
3715 static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
3716 {
3717         struct strbuf buf = STRBUF_INIT;
3718         char *dirty = "";
3719
3720         /* Are we looking at the work tree? */
3721         if (s->dirty_submodule)
3722                 dirty = "-dirty";
3723
3724         strbuf_addf(&buf, "Subproject commit %s%s\n",
3725                     oid_to_hex(&s->oid), dirty);
3726         s->size = buf.len;
3727         if (size_only) {
3728                 s->data = NULL;
3729                 strbuf_release(&buf);
3730         } else {
3731                 s->data = strbuf_detach(&buf, NULL);
3732                 s->should_free = 1;
3733         }
3734         return 0;
3735 }
3736
3737 /*
3738  * While doing rename detection and pickaxe operation, we may need to
3739  * grab the data for the blob (or file) for our own in-core comparison.
3740  * diff_filespec has data and size fields for this purpose.
3741  */
3742 int diff_populate_filespec(struct diff_filespec *s, unsigned int flags)
3743 {
3744         int size_only = flags & CHECK_SIZE_ONLY;
3745         int err = 0;
3746         int conv_flags = global_conv_flags_eol;
3747         /*
3748          * demote FAIL to WARN to allow inspecting the situation
3749          * instead of refusing.
3750          */
3751         if (conv_flags & CONV_EOL_RNDTRP_DIE)
3752                 conv_flags = CONV_EOL_RNDTRP_WARN;
3753
3754         if (!DIFF_FILE_VALID(s))
3755                 die("internal error: asking to populate invalid file.");
3756         if (S_ISDIR(s->mode))
3757                 return -1;
3758
3759         if (s->data)
3760                 return 0;
3761
3762         if (size_only && 0 < s->size)
3763                 return 0;
3764
3765         if (S_ISGITLINK(s->mode))
3766                 return diff_populate_gitlink(s, size_only);
3767
3768         if (!s->oid_valid ||
3769             reuse_worktree_file(s->path, &s->oid, 0)) {
3770                 struct strbuf buf = STRBUF_INIT;
3771                 struct stat st;
3772                 int fd;
3773
3774                 if (lstat(s->path, &st) < 0) {
3775                 err_empty:
3776                         err = -1;
3777                 empty:
3778                         s->data = (char *)"";
3779                         s->size = 0;
3780                         return err;
3781                 }
3782                 s->size = xsize_t(st.st_size);
3783                 if (!s->size)
3784                         goto empty;
3785                 if (S_ISLNK(st.st_mode)) {
3786                         struct strbuf sb = STRBUF_INIT;
3787
3788                         if (strbuf_readlink(&sb, s->path, s->size))
3789                                 goto err_empty;
3790                         s->size = sb.len;
3791                         s->data = strbuf_detach(&sb, NULL);
3792                         s->should_free = 1;
3793                         return 0;
3794                 }
3795
3796                 /*
3797                  * Even if the caller would be happy with getting
3798                  * only the size, we cannot return early at this
3799                  * point if the path requires us to run the content
3800                  * conversion.
3801                  */
3802                 if (size_only && !would_convert_to_git(&the_index, s->path))
3803                         return 0;
3804
3805                 /*
3806                  * Note: this check uses xsize_t(st.st_size) that may
3807                  * not be the true size of the blob after it goes
3808                  * through convert_to_git().  This may not strictly be
3809                  * correct, but the whole point of big_file_threshold
3810                  * and is_binary check being that we want to avoid
3811                  * opening the file and inspecting the contents, this
3812                  * is probably fine.
3813                  */
3814                 if ((flags & CHECK_BINARY) &&
3815                     s->size > big_file_threshold && s->is_binary == -1) {
3816                         s->is_binary = 1;
3817                         return 0;
3818                 }
3819                 fd = open(s->path, O_RDONLY);
3820                 if (fd < 0)
3821                         goto err_empty;
3822                 s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
3823                 close(fd);
3824                 s->should_munmap = 1;
3825
3826                 /*
3827                  * Convert from working tree format to canonical git format
3828                  */
3829                 if (convert_to_git(&the_index, s->path, s->data, s->size, &buf, conv_flags)) {
3830                         size_t size = 0;
3831                         munmap(s->data, s->size);
3832                         s->should_munmap = 0;
3833                         s->data = strbuf_detach(&buf, &size);
3834                         s->size = size;
3835                         s->should_free = 1;
3836                 }
3837         }
3838         else {
3839                 enum object_type type;
3840                 if (size_only || (flags & CHECK_BINARY)) {
3841                         type = oid_object_info(the_repository, &s->oid,
3842                                                &s->size);
3843                         if (type < 0)
3844                                 die("unable to read %s",
3845                                     oid_to_hex(&s->oid));
3846                         if (size_only)
3847                                 return 0;
3848                         if (s->size > big_file_threshold && s->is_binary == -1) {
3849                                 s->is_binary = 1;
3850                                 return 0;
3851                         }
3852                 }
3853                 s->data = read_object_file(&s->oid, &type, &s->size);
3854                 if (!s->data)
3855                         die("unable to read %s", oid_to_hex(&s->oid));
3856                 s->should_free = 1;
3857         }
3858         return 0;
3859 }
3860
3861 void diff_free_filespec_blob(struct diff_filespec *s)
3862 {
3863         if (s->should_free)
3864                 free(s->data);
3865         else if (s->should_munmap)
3866                 munmap(s->data, s->size);
3867
3868         if (s->should_free || s->should_munmap) {
3869                 s->should_free = s->should_munmap = 0;
3870                 s->data = NULL;
3871         }
3872 }
3873
3874 void diff_free_filespec_data(struct diff_filespec *s)
3875 {
3876         diff_free_filespec_blob(s);
3877         FREE_AND_NULL(s->cnt_data);
3878 }
3879
3880 static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
3881                            void *blob,
3882                            unsigned long size,
3883                            const struct object_id *oid,
3884                            int mode)
3885 {
3886         struct strbuf buf = STRBUF_INIT;
3887         struct strbuf tempfile = STRBUF_INIT;
3888         char *path_dup = xstrdup(path);
3889         const char *base = basename(path_dup);
3890
3891         /* Generate "XXXXXX_basename.ext" */
3892         strbuf_addstr(&tempfile, "XXXXXX_");
3893         strbuf_addstr(&tempfile, base);
3894
3895         temp->tempfile = mks_tempfile_ts(tempfile.buf, strlen(base) + 1);
3896         if (!temp->tempfile)
3897                 die_errno("unable to create temp-file");
3898         if (convert_to_working_tree(path,
3899                         (const char *)blob, (size_t)size, &buf)) {
3900                 blob = buf.buf;
3901                 size = buf.len;
3902         }
3903         if (write_in_full(temp->tempfile->fd, blob, size) < 0 ||
3904             close_tempfile_gently(temp->tempfile))
3905                 die_errno("unable to write temp-file");
3906         temp->name = get_tempfile_path(temp->tempfile);
3907         oid_to_hex_r(temp->hex, oid);
3908         xsnprintf(temp->mode, sizeof(temp->mode), "%06o", mode);
3909         strbuf_release(&buf);
3910         strbuf_release(&tempfile);
3911         free(path_dup);
3912 }
3913
3914 static struct diff_tempfile *prepare_temp_file(const char *name,
3915                 struct diff_filespec *one)
3916 {
3917         struct diff_tempfile *temp = claim_diff_tempfile();
3918
3919         if (!DIFF_FILE_VALID(one)) {
3920         not_a_valid_file:
3921                 /* A '-' entry produces this for file-2, and
3922                  * a '+' entry produces this for file-1.
3923                  */
3924                 temp->name = "/dev/null";
3925                 xsnprintf(temp->hex, sizeof(temp->hex), ".");
3926                 xsnprintf(temp->mode, sizeof(temp->mode), ".");
3927                 return temp;
3928         }
3929
3930         if (!S_ISGITLINK(one->mode) &&
3931             (!one->oid_valid ||
3932              reuse_worktree_file(name, &one->oid, 1))) {
3933                 struct stat st;
3934                 if (lstat(name, &st) < 0) {
3935                         if (errno == ENOENT)
3936                                 goto not_a_valid_file;
3937                         die_errno("stat(%s)", name);
3938                 }
3939                 if (S_ISLNK(st.st_mode)) {
3940                         struct strbuf sb = STRBUF_INIT;
3941                         if (strbuf_readlink(&sb, name, st.st_size) < 0)
3942                                 die_errno("readlink(%s)", name);
3943                         prep_temp_blob(name, temp, sb.buf, sb.len,
3944                                        (one->oid_valid ?
3945                                         &one->oid : &null_oid),
3946                                        (one->oid_valid ?
3947                                         one->mode : S_IFLNK));
3948                         strbuf_release(&sb);
3949                 }
3950                 else {
3951                         /* we can borrow from the file in the work tree */
3952                         temp->name = name;
3953                         if (!one->oid_valid)
3954                                 oid_to_hex_r(temp->hex, &null_oid);
3955                         else
3956                                 oid_to_hex_r(temp->hex, &one->oid);
3957                         /* Even though we may sometimes borrow the
3958                          * contents from the work tree, we always want
3959                          * one->mode.  mode is trustworthy even when
3960                          * !(one->oid_valid), as long as
3961                          * DIFF_FILE_VALID(one).
3962                          */
3963                         xsnprintf(temp->mode, sizeof(temp->mode), "%06o", one->mode);
3964                 }
3965                 return temp;
3966         }
3967         else {
3968                 if (diff_populate_filespec(one, 0))
3969                         die("cannot read data blob for %s", one->path);
3970                 prep_temp_blob(name, temp, one->data, one->size,
3971                                &one->oid, one->mode);
3972         }
3973         return temp;
3974 }
3975
3976 static void add_external_diff_name(struct argv_array *argv,
3977                                    const char *name,
3978                                    struct diff_filespec *df)
3979 {
3980         struct diff_tempfile *temp = prepare_temp_file(name, df);
3981         argv_array_push(argv, temp->name);
3982         argv_array_push(argv, temp->hex);
3983         argv_array_push(argv, temp->mode);
3984 }
3985
3986 /* An external diff command takes:
3987  *
3988  * diff-cmd name infile1 infile1-sha1 infile1-mode \
3989  *               infile2 infile2-sha1 infile2-mode [ rename-to ]
3990  *
3991  */
3992 static void run_external_diff(const char *pgm,
3993                               const char *name,
3994                               const char *other,
3995                               struct diff_filespec *one,
3996                               struct diff_filespec *two,
3997                               const char *xfrm_msg,
3998                               int complete_rewrite,
3999                               struct diff_options *o)
4000 {
4001         struct argv_array argv = ARGV_ARRAY_INIT;
4002         struct argv_array env = ARGV_ARRAY_INIT;
4003         struct diff_queue_struct *q = &diff_queued_diff;
4004
4005         argv_array_push(&argv, pgm);
4006         argv_array_push(&argv, name);
4007
4008         if (one && two) {
4009                 add_external_diff_name(&argv, name, one);
4010                 if (!other)
4011                         add_external_diff_name(&argv, name, two);
4012                 else {
4013                         add_external_diff_name(&argv, other, two);
4014                         argv_array_push(&argv, other);
4015                         argv_array_push(&argv, xfrm_msg);
4016                 }
4017         }
4018
4019         argv_array_pushf(&env, "GIT_DIFF_PATH_COUNTER=%d", ++o->diff_path_counter);
4020         argv_array_pushf(&env, "GIT_DIFF_PATH_TOTAL=%d", q->nr);
4021
4022         if (run_command_v_opt_cd_env(argv.argv, RUN_USING_SHELL, NULL, env.argv))
4023                 die(_("external diff died, stopping at %s"), name);
4024
4025         remove_tempfile();
4026         argv_array_clear(&argv);
4027         argv_array_clear(&env);
4028 }
4029
4030 static int similarity_index(struct diff_filepair *p)
4031 {
4032         return p->score * 100 / MAX_SCORE;
4033 }
4034
4035 static const char *diff_abbrev_oid(const struct object_id *oid, int abbrev)
4036 {
4037         if (startup_info->have_repository)
4038                 return find_unique_abbrev(oid, abbrev);
4039         else {
4040                 char *hex = oid_to_hex(oid);
4041                 if (abbrev < 0)
4042                         abbrev = FALLBACK_DEFAULT_ABBREV;
4043                 if (abbrev > the_hash_algo->hexsz)
4044                         BUG("oid abbreviation out of range: %d", abbrev);
4045                 if (abbrev)
4046                         hex[abbrev] = '\0';
4047                 return hex;
4048         }
4049 }
4050
4051 static void fill_metainfo(struct strbuf *msg,
4052                           const char *name,
4053                           const char *other,
4054                           struct diff_filespec *one,
4055                           struct diff_filespec *two,
4056                           struct diff_options *o,
4057                           struct diff_filepair *p,
4058                           int *must_show_header,
4059                           int use_color)
4060 {
4061         const char *set = diff_get_color(use_color, DIFF_METAINFO);
4062         const char *reset = diff_get_color(use_color, DIFF_RESET);
4063         const char *line_prefix = diff_line_prefix(o);
4064
4065         *must_show_header = 1;
4066         strbuf_init(msg, PATH_MAX * 2 + 300);
4067         switch (p->status) {
4068         case DIFF_STATUS_COPIED:
4069                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
4070                             line_prefix, set, similarity_index(p));
4071                 strbuf_addf(msg, "%s\n%s%scopy from ",
4072                             reset,  line_prefix, set);
4073                 quote_c_style(name, msg, NULL, 0);
4074                 strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
4075                 quote_c_style(other, msg, NULL, 0);
4076                 strbuf_addf(msg, "%s\n", reset);
4077                 break;
4078         case DIFF_STATUS_RENAMED:
4079                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
4080                             line_prefix, set, similarity_index(p));
4081                 strbuf_addf(msg, "%s\n%s%srename from ",
4082                             reset, line_prefix, set);
4083                 quote_c_style(name, msg, NULL, 0);
4084                 strbuf_addf(msg, "%s\n%s%srename to ",
4085                             reset, line_prefix, set);
4086                 quote_c_style(other, msg, NULL, 0);
4087                 strbuf_addf(msg, "%s\n", reset);
4088                 break;
4089         case DIFF_STATUS_MODIFIED:
4090                 if (p->score) {
4091                         strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
4092                                     line_prefix,
4093                                     set, similarity_index(p), reset);
4094                         break;
4095                 }
4096                 /* fallthru */
4097         default:
4098                 *must_show_header = 0;
4099         }
4100         if (one && two && oidcmp(&one->oid, &two->oid)) {
4101                 const unsigned hexsz = the_hash_algo->hexsz;
4102                 int abbrev = o->flags.full_index ? hexsz : DEFAULT_ABBREV;
4103
4104                 if (o->flags.binary) {
4105                         mmfile_t mf;
4106                         if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
4107                             (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
4108                                 abbrev = hexsz;
4109                 }
4110                 strbuf_addf(msg, "%s%sindex %s..%s", line_prefix, set,
4111                             diff_abbrev_oid(&one->oid, abbrev),
4112                             diff_abbrev_oid(&two->oid, abbrev));
4113                 if (one->mode == two->mode)
4114                         strbuf_addf(msg, " %06o", one->mode);
4115                 strbuf_addf(msg, "%s\n", reset);
4116         }
4117 }
4118
4119 static void run_diff_cmd(const char *pgm,
4120                          const char *name,
4121                          const char *other,
4122                          const char *attr_path,
4123                          struct diff_filespec *one,
4124                          struct diff_filespec *two,
4125                          struct strbuf *msg,
4126                          struct diff_options *o,
4127                          struct diff_filepair *p)
4128 {
4129         const char *xfrm_msg = NULL;
4130         int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
4131         int must_show_header = 0;
4132
4133
4134         if (o->flags.allow_external) {
4135                 struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
4136                 if (drv && drv->external)
4137                         pgm = drv->external;
4138         }
4139
4140         if (msg) {
4141                 /*
4142                  * don't use colors when the header is intended for an
4143                  * external diff driver
4144                  */
4145                 fill_metainfo(msg, name, other, one, two, o, p,
4146                               &must_show_header,
4147                               want_color(o->use_color) && !pgm);
4148                 xfrm_msg = msg->len ? msg->buf : NULL;
4149         }
4150
4151         if (pgm) {
4152                 run_external_diff(pgm, name, other, one, two, xfrm_msg,
4153                                   complete_rewrite, o);
4154                 return;
4155         }
4156         if (one && two)
4157                 builtin_diff(name, other ? other : name,
4158                              one, two, xfrm_msg, must_show_header,
4159                              o, complete_rewrite);
4160         else
4161                 fprintf(o->file, "* Unmerged path %s\n", name);
4162 }
4163
4164 static void diff_fill_oid_info(struct diff_filespec *one)
4165 {
4166         if (DIFF_FILE_VALID(one)) {
4167                 if (!one->oid_valid) {
4168                         struct stat st;
4169                         if (one->is_stdin) {
4170                                 oidclr(&one->oid);
4171                                 return;
4172                         }
4173                         if (lstat(one->path, &st) < 0)
4174                                 die_errno("stat '%s'", one->path);
4175                         if (index_path(&one->oid, one->path, &st, 0))
4176                                 die("cannot hash %s", one->path);
4177                 }
4178         }
4179         else
4180                 oidclr(&one->oid);
4181 }
4182
4183 static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
4184 {
4185         /* Strip the prefix but do not molest /dev/null and absolute paths */
4186         if (*namep && **namep != '/') {
4187                 *namep += prefix_length;
4188                 if (**namep == '/')
4189                         ++*namep;
4190         }
4191         if (*otherp && **otherp != '/') {
4192                 *otherp += prefix_length;
4193                 if (**otherp == '/')
4194                         ++*otherp;
4195         }
4196 }
4197
4198 static void run_diff(struct diff_filepair *p, struct diff_options *o)
4199 {
4200         const char *pgm = external_diff();
4201         struct strbuf msg;
4202         struct diff_filespec *one = p->one;
4203         struct diff_filespec *two = p->two;
4204         const char *name;
4205         const char *other;
4206         const char *attr_path;
4207
4208         name  = one->path;
4209         other = (strcmp(name, two->path) ? two->path : NULL);
4210         attr_path = name;
4211         if (o->prefix_length)
4212                 strip_prefix(o->prefix_length, &name, &other);
4213
4214         if (!o->flags.allow_external)
4215                 pgm = NULL;
4216
4217         if (DIFF_PAIR_UNMERGED(p)) {
4218                 run_diff_cmd(pgm, name, NULL, attr_path,
4219                              NULL, NULL, NULL, o, p);
4220                 return;
4221         }
4222
4223         diff_fill_oid_info(one);
4224         diff_fill_oid_info(two);
4225
4226         if (!pgm &&
4227             DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
4228             (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
4229                 /*
4230                  * a filepair that changes between file and symlink
4231                  * needs to be split into deletion and creation.
4232                  */
4233                 struct diff_filespec *null = alloc_filespec(two->path);
4234                 run_diff_cmd(NULL, name, other, attr_path,
4235                              one, null, &msg, o, p);
4236                 free(null);
4237                 strbuf_release(&msg);
4238
4239                 null = alloc_filespec(one->path);
4240                 run_diff_cmd(NULL, name, other, attr_path,
4241                              null, two, &msg, o, p);
4242                 free(null);
4243         }
4244         else
4245                 run_diff_cmd(pgm, name, other, attr_path,
4246                              one, two, &msg, o, p);
4247
4248         strbuf_release(&msg);
4249 }
4250
4251 static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
4252                          struct diffstat_t *diffstat)
4253 {
4254         const char *name;
4255         const char *other;
4256
4257         if (DIFF_PAIR_UNMERGED(p)) {
4258                 /* unmerged */
4259                 builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, p);
4260                 return;
4261         }
4262
4263         name = p->one->path;
4264         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
4265
4266         if (o->prefix_length)
4267                 strip_prefix(o->prefix_length, &name, &other);
4268
4269         diff_fill_oid_info(p->one);
4270         diff_fill_oid_info(p->two);
4271
4272         builtin_diffstat(name, other, p->one, p->two, diffstat, o, p);
4273 }
4274
4275 static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
4276 {
4277         const char *name;
4278         const char *other;
4279         const char *attr_path;
4280
4281         if (DIFF_PAIR_UNMERGED(p)) {
4282                 /* unmerged */
4283                 return;
4284         }
4285
4286         name = p->one->path;
4287         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
4288         attr_path = other ? other : name;
4289
4290         if (o->prefix_length)
4291                 strip_prefix(o->prefix_length, &name, &other);
4292
4293         diff_fill_oid_info(p->one);
4294         diff_fill_oid_info(p->two);
4295
4296         builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
4297 }
4298
4299 void diff_setup(struct diff_options *options)
4300 {
4301         memcpy(options, &default_diff_options, sizeof(*options));
4302
4303         options->file = stdout;
4304
4305         options->abbrev = DEFAULT_ABBREV;
4306         options->line_termination = '\n';
4307         options->break_opt = -1;
4308         options->rename_limit = -1;
4309         options->dirstat_permille = diff_dirstat_permille_default;
4310         options->context = diff_context_default;
4311         options->interhunkcontext = diff_interhunk_context_default;
4312         options->ws_error_highlight = ws_error_highlight_default;
4313         options->flags.rename_empty = 1;
4314         options->objfind = NULL;
4315
4316         /* pathchange left =NULL by default */
4317         options->change = diff_change;
4318         options->add_remove = diff_addremove;
4319         options->use_color = diff_use_color_default;
4320         options->detect_rename = diff_detect_rename_default;
4321         options->xdl_opts |= diff_algorithm;
4322         if (diff_indent_heuristic)
4323                 DIFF_XDL_SET(options, INDENT_HEURISTIC);
4324
4325         options->orderfile = diff_order_file_cfg;
4326
4327         if (diff_no_prefix) {
4328                 options->a_prefix = options->b_prefix = "";
4329         } else if (!diff_mnemonic_prefix) {
4330                 options->a_prefix = "a/";
4331                 options->b_prefix = "b/";
4332         }
4333
4334         options->color_moved = diff_color_moved_default;
4335         options->color_moved_ws_handling = diff_color_moved_ws_default;
4336 }
4337
4338 void diff_setup_done(struct diff_options *options)
4339 {
4340         unsigned check_mask = DIFF_FORMAT_NAME |
4341                               DIFF_FORMAT_NAME_STATUS |
4342                               DIFF_FORMAT_CHECKDIFF |
4343                               DIFF_FORMAT_NO_OUTPUT;
4344         /*
4345          * This must be signed because we're comparing against a potentially
4346          * negative value.
4347          */
4348         const int hexsz = the_hash_algo->hexsz;
4349
4350         if (options->set_default)
4351                 options->set_default(options);
4352
4353         if (HAS_MULTI_BITS(options->output_format & check_mask))
4354                 die(_("--name-only, --name-status, --check and -s are mutually exclusive"));
4355
4356         if (HAS_MULTI_BITS(options->pickaxe_opts & DIFF_PICKAXE_KINDS_MASK))
4357                 die(_("-G, -S and --find-object are mutually exclusive"));
4358
4359         /*
4360          * Most of the time we can say "there are changes"
4361          * only by checking if there are changed paths, but
4362          * --ignore-whitespace* options force us to look
4363          * inside contents.
4364          */
4365
4366         if ((options->xdl_opts & XDF_WHITESPACE_FLAGS))
4367                 options->flags.diff_from_contents = 1;
4368         else
4369                 options->flags.diff_from_contents = 0;
4370
4371         if (options->flags.find_copies_harder)
4372                 options->detect_rename = DIFF_DETECT_COPY;
4373
4374         if (!options->flags.relative_name)
4375                 options->prefix = NULL;
4376         if (options->prefix)
4377                 options->prefix_length = strlen(options->prefix);
4378         else
4379                 options->prefix_length = 0;
4380
4381         if (options->output_format & (DIFF_FORMAT_NAME |
4382                                       DIFF_FORMAT_NAME_STATUS |
4383                                       DIFF_FORMAT_CHECKDIFF |
4384                                       DIFF_FORMAT_NO_OUTPUT))
4385                 options->output_format &= ~(DIFF_FORMAT_RAW |
4386                                             DIFF_FORMAT_NUMSTAT |
4387                                             DIFF_FORMAT_DIFFSTAT |
4388                                             DIFF_FORMAT_SHORTSTAT |
4389                                             DIFF_FORMAT_DIRSTAT |
4390                                             DIFF_FORMAT_SUMMARY |
4391                                             DIFF_FORMAT_PATCH);
4392
4393         /*
4394          * These cases always need recursive; we do not drop caller-supplied
4395          * recursive bits for other formats here.
4396          */
4397         if (options->output_format & (DIFF_FORMAT_PATCH |
4398                                       DIFF_FORMAT_NUMSTAT |
4399                                       DIFF_FORMAT_DIFFSTAT |
4400                                       DIFF_FORMAT_SHORTSTAT |
4401                                       DIFF_FORMAT_DIRSTAT |
4402                                       DIFF_FORMAT_SUMMARY |
4403                                       DIFF_FORMAT_CHECKDIFF))
4404                 options->flags.recursive = 1;
4405         /*
4406          * Also pickaxe would not work very well if you do not say recursive
4407          */
4408         if (options->pickaxe_opts & DIFF_PICKAXE_KINDS_MASK)
4409                 options->flags.recursive = 1;
4410         /*
4411          * When patches are generated, submodules diffed against the work tree
4412          * must be checked for dirtiness too so it can be shown in the output
4413          */
4414         if (options->output_format & DIFF_FORMAT_PATCH)
4415                 options->flags.dirty_submodules = 1;
4416
4417         if (options->detect_rename && options->rename_limit < 0)
4418                 options->rename_limit = diff_rename_limit_default;
4419         if (options->setup & DIFF_SETUP_USE_CACHE) {
4420                 if (!active_cache)
4421                         /* read-cache does not die even when it fails
4422                          * so it is safe for us to do this here.  Also
4423                          * it does not smudge active_cache or active_nr
4424                          * when it fails, so we do not have to worry about
4425                          * cleaning it up ourselves either.
4426                          */
4427                         read_cache();
4428         }
4429         if (hexsz < options->abbrev)
4430                 options->abbrev = hexsz; /* full */
4431
4432         /*
4433          * It does not make sense to show the first hit we happened
4434          * to have found.  It does not make sense not to return with
4435          * exit code in such a case either.
4436          */
4437         if (options->flags.quick) {
4438                 options->output_format = DIFF_FORMAT_NO_OUTPUT;
4439                 options->flags.exit_with_status = 1;
4440         }
4441
4442         options->diff_path_counter = 0;
4443
4444         if (options->flags.follow_renames && options->pathspec.nr != 1)
4445                 die(_("--follow requires exactly one pathspec"));
4446
4447         if (!options->use_color || external_diff())
4448                 options->color_moved = 0;
4449 }
4450
4451 static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
4452 {
4453         char c, *eq;
4454         int len;
4455
4456         if (*arg != '-')
4457                 return 0;
4458         c = *++arg;
4459         if (!c)
4460                 return 0;
4461         if (c == arg_short) {
4462                 c = *++arg;
4463                 if (!c)
4464                         return 1;
4465                 if (val && isdigit(c)) {
4466                         char *end;
4467                         int n = strtoul(arg, &end, 10);
4468                         if (*end)
4469                                 return 0;
4470                         *val = n;
4471                         return 1;
4472                 }
4473                 return 0;
4474         }
4475         if (c != '-')
4476                 return 0;
4477         arg++;
4478         eq = strchrnul(arg, '=');
4479         len = eq - arg;
4480         if (!len || strncmp(arg, arg_long, len))
4481                 return 0;
4482         if (*eq) {
4483                 int n;
4484                 char *end;
4485                 if (!isdigit(*++eq))
4486                         return 0;
4487                 n = strtoul(eq, &end, 10);
4488                 if (*end)
4489                         return 0;
4490                 *val = n;
4491         }
4492         return 1;
4493 }
4494
4495 static int diff_scoreopt_parse(const char *opt);
4496
4497 static inline int short_opt(char opt, const char **argv,
4498                             const char **optarg)
4499 {
4500         const char *arg = argv[0];
4501         if (arg[0] != '-' || arg[1] != opt)
4502                 return 0;
4503         if (arg[2] != '\0') {
4504                 *optarg = arg + 2;
4505                 return 1;
4506         }
4507         if (!argv[1])
4508                 die("Option '%c' requires a value", opt);
4509         *optarg = argv[1];
4510         return 2;
4511 }
4512
4513 int parse_long_opt(const char *opt, const char **argv,
4514                    const char **optarg)
4515 {
4516         const char *arg = argv[0];
4517         if (!skip_prefix(arg, "--", &arg))
4518                 return 0;
4519         if (!skip_prefix(arg, opt, &arg))
4520                 return 0;
4521         if (*arg == '=') { /* stuck form: --option=value */
4522                 *optarg = arg + 1;
4523                 return 1;
4524         }
4525         if (*arg != '\0')
4526                 return 0;
4527         /* separate form: --option value */
4528         if (!argv[1])
4529                 die("Option '--%s' requires a value", opt);
4530         *optarg = argv[1];
4531         return 2;
4532 }
4533
4534 static int stat_opt(struct diff_options *options, const char **av)
4535 {
4536         const char *arg = av[0];
4537         char *end;
4538         int width = options->stat_width;
4539         int name_width = options->stat_name_width;
4540         int graph_width = options->stat_graph_width;
4541         int count = options->stat_count;
4542         int argcount = 1;
4543
4544         if (!skip_prefix(arg, "--stat", &arg))
4545                 BUG("stat option does not begin with --stat: %s", arg);
4546         end = (char *)arg;
4547
4548         switch (*arg) {
4549         case '-':
4550                 if (skip_prefix(arg, "-width", &arg)) {
4551                         if (*arg == '=')
4552                                 width = strtoul(arg + 1, &end, 10);
4553                         else if (!*arg && !av[1])
4554                                 die_want_option("--stat-width");
4555                         else if (!*arg) {
4556                                 width = strtoul(av[1], &end, 10);
4557                                 argcount = 2;
4558                         }
4559                 } else if (skip_prefix(arg, "-name-width", &arg)) {
4560                         if (*arg == '=')
4561                                 name_width = strtoul(arg + 1, &end, 10);
4562                         else if (!*arg && !av[1])
4563                                 die_want_option("--stat-name-width");
4564                         else if (!*arg) {
4565                                 name_width = strtoul(av[1], &end, 10);
4566                                 argcount = 2;
4567                         }
4568                 } else if (skip_prefix(arg, "-graph-width", &arg)) {
4569                         if (*arg == '=')
4570                                 graph_width = strtoul(arg + 1, &end, 10);
4571                         else if (!*arg && !av[1])
4572                                 die_want_option("--stat-graph-width");
4573                         else if (!*arg) {
4574                                 graph_width = strtoul(av[1], &end, 10);
4575                                 argcount = 2;
4576                         }
4577                 } else if (skip_prefix(arg, "-count", &arg)) {
4578                         if (*arg == '=')
4579                                 count = strtoul(arg + 1, &end, 10);
4580                         else if (!*arg && !av[1])
4581                                 die_want_option("--stat-count");
4582                         else if (!*arg) {
4583                                 count = strtoul(av[1], &end, 10);
4584                                 argcount = 2;
4585                         }
4586                 }
4587                 break;
4588         case '=':
4589                 width = strtoul(arg+1, &end, 10);
4590                 if (*end == ',')
4591                         name_width = strtoul(end+1, &end, 10);
4592                 if (*end == ',')
4593                         count = strtoul(end+1, &end, 10);
4594         }
4595
4596         /* Important! This checks all the error cases! */
4597         if (*end)
4598                 return 0;
4599         options->output_format |= DIFF_FORMAT_DIFFSTAT;
4600         options->stat_name_width = name_width;
4601         options->stat_graph_width = graph_width;
4602         options->stat_width = width;
4603         options->stat_count = count;
4604         return argcount;
4605 }
4606
4607 static int parse_dirstat_opt(struct diff_options *options, const char *params)
4608 {
4609         struct strbuf errmsg = STRBUF_INIT;
4610         if (parse_dirstat_params(options, params, &errmsg))
4611                 die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
4612                     errmsg.buf);
4613         strbuf_release(&errmsg);
4614         /*
4615          * The caller knows a dirstat-related option is given from the command
4616          * line; allow it to say "return this_function();"
4617          */
4618         options->output_format |= DIFF_FORMAT_DIRSTAT;
4619         return 1;
4620 }
4621
4622 static int parse_submodule_opt(struct diff_options *options, const char *value)
4623 {
4624         if (parse_submodule_params(options, value))
4625                 die(_("Failed to parse --submodule option parameter: '%s'"),
4626                         value);
4627         return 1;
4628 }
4629
4630 static const char diff_status_letters[] = {
4631         DIFF_STATUS_ADDED,
4632         DIFF_STATUS_COPIED,
4633         DIFF_STATUS_DELETED,
4634         DIFF_STATUS_MODIFIED,
4635         DIFF_STATUS_RENAMED,
4636         DIFF_STATUS_TYPE_CHANGED,
4637         DIFF_STATUS_UNKNOWN,
4638         DIFF_STATUS_UNMERGED,
4639         DIFF_STATUS_FILTER_AON,
4640         DIFF_STATUS_FILTER_BROKEN,
4641         '\0',
4642 };
4643
4644 static unsigned int filter_bit['Z' + 1];
4645
4646 static void prepare_filter_bits(void)
4647 {
4648         int i;
4649
4650         if (!filter_bit[DIFF_STATUS_ADDED]) {
4651                 for (i = 0; diff_status_letters[i]; i++)
4652                         filter_bit[(int) diff_status_letters[i]] = (1 << i);
4653         }
4654 }
4655
4656 static unsigned filter_bit_tst(char status, const struct diff_options *opt)
4657 {
4658         return opt->filter & filter_bit[(int) status];
4659 }
4660
4661 static int parse_diff_filter_opt(const char *optarg, struct diff_options *opt)
4662 {
4663         int i, optch;
4664
4665         prepare_filter_bits();
4666
4667         /*
4668          * If there is a negation e.g. 'd' in the input, and we haven't
4669          * initialized the filter field with another --diff-filter, start
4670          * from full set of bits, except for AON.
4671          */
4672         if (!opt->filter) {
4673                 for (i = 0; (optch = optarg[i]) != '\0'; i++) {
4674                         if (optch < 'a' || 'z' < optch)
4675                                 continue;
4676                         opt->filter = (1 << (ARRAY_SIZE(diff_status_letters) - 1)) - 1;
4677                         opt->filter &= ~filter_bit[DIFF_STATUS_FILTER_AON];
4678                         break;
4679                 }
4680         }
4681
4682         for (i = 0; (optch = optarg[i]) != '\0'; i++) {
4683                 unsigned int bit;
4684                 int negate;
4685
4686                 if ('a' <= optch && optch <= 'z') {
4687                         negate = 1;
4688                         optch = toupper(optch);
4689                 } else {
4690                         negate = 0;
4691                 }
4692
4693                 bit = (0 <= optch && optch <= 'Z') ? filter_bit[optch] : 0;
4694                 if (!bit)
4695                         return optarg[i];
4696                 if (negate)
4697                         opt->filter &= ~bit;
4698                 else
4699                         opt->filter |= bit;
4700         }
4701         return 0;
4702 }
4703
4704 static void enable_patch_output(int *fmt) {
4705         *fmt &= ~DIFF_FORMAT_NO_OUTPUT;
4706         *fmt |= DIFF_FORMAT_PATCH;
4707 }
4708
4709 static int parse_ws_error_highlight_opt(struct diff_options *opt, const char *arg)
4710 {
4711         int val = parse_ws_error_highlight(arg);
4712
4713         if (val < 0) {
4714                 error("unknown value after ws-error-highlight=%.*s",
4715                       -1 - val, arg);
4716                 return 0;
4717         }
4718         opt->ws_error_highlight = val;
4719         return 1;
4720 }
4721
4722 static int parse_objfind_opt(struct diff_options *opt, const char *arg)
4723 {
4724         struct object_id oid;
4725
4726         if (get_oid(arg, &oid))
4727                 return error("unable to resolve '%s'", arg);
4728
4729         if (!opt->objfind)
4730                 opt->objfind = xcalloc(1, sizeof(*opt->objfind));
4731
4732         opt->pickaxe_opts |= DIFF_PICKAXE_KIND_OBJFIND;
4733         opt->flags.recursive = 1;
4734         opt->flags.tree_in_recursive = 1;
4735         oidset_insert(opt->objfind, &oid);
4736         return 1;
4737 }
4738
4739 int diff_opt_parse(struct diff_options *options,
4740                    const char **av, int ac, const char *prefix)
4741 {
4742         const char *arg = av[0];
4743         const char *optarg;
4744         int argcount;
4745
4746         if (!prefix)
4747                 prefix = "";
4748
4749         /* Output format options */
4750         if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch")
4751             || opt_arg(arg, 'U', "unified", &options->context))
4752                 enable_patch_output(&options->output_format);
4753         else if (!strcmp(arg, "--raw"))
4754                 options->output_format |= DIFF_FORMAT_RAW;
4755         else if (!strcmp(arg, "--patch-with-raw")) {
4756                 enable_patch_output(&options->output_format);
4757                 options->output_format |= DIFF_FORMAT_RAW;
4758         } else if (!strcmp(arg, "--numstat"))
4759                 options->output_format |= DIFF_FORMAT_NUMSTAT;
4760         else if (!strcmp(arg, "--shortstat"))
4761                 options->output_format |= DIFF_FORMAT_SHORTSTAT;
4762         else if (skip_prefix(arg, "-X", &arg) ||
4763                  skip_to_optional_arg(arg, "--dirstat", &arg))
4764                 return parse_dirstat_opt(options, arg);
4765         else if (!strcmp(arg, "--cumulative"))
4766                 return parse_dirstat_opt(options, "cumulative");
4767         else if (skip_to_optional_arg(arg, "--dirstat-by-file", &arg)) {
4768                 parse_dirstat_opt(options, "files");
4769                 return parse_dirstat_opt(options, arg);
4770         }
4771         else if (!strcmp(arg, "--check"))
4772                 options->output_format |= DIFF_FORMAT_CHECKDIFF;
4773         else if (!strcmp(arg, "--summary"))
4774                 options->output_format |= DIFF_FORMAT_SUMMARY;
4775         else if (!strcmp(arg, "--patch-with-stat")) {
4776                 enable_patch_output(&options->output_format);
4777                 options->output_format |= DIFF_FORMAT_DIFFSTAT;
4778         } else if (!strcmp(arg, "--name-only"))
4779                 options->output_format |= DIFF_FORMAT_NAME;
4780         else if (!strcmp(arg, "--name-status"))
4781                 options->output_format |= DIFF_FORMAT_NAME_STATUS;
4782         else if (!strcmp(arg, "-s") || !strcmp(arg, "--no-patch"))
4783                 options->output_format |= DIFF_FORMAT_NO_OUTPUT;
4784         else if (starts_with(arg, "--stat"))
4785                 /* --stat, --stat-width, --stat-name-width, or --stat-count */
4786                 return stat_opt(options, av);
4787         else if (!strcmp(arg, "--compact-summary")) {
4788                  options->flags.stat_with_summary = 1;
4789                  options->output_format |= DIFF_FORMAT_DIFFSTAT;
4790         } else if (!strcmp(arg, "--no-compact-summary"))
4791                  options->flags.stat_with_summary = 0;
4792
4793         /* renames options */
4794         else if (starts_with(arg, "-B") ||
4795                  skip_to_optional_arg(arg, "--break-rewrites", NULL)) {
4796                 if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
4797                         return error("invalid argument to -B: %s", arg+2);
4798         }
4799         else if (starts_with(arg, "-M") ||
4800                  skip_to_optional_arg(arg, "--find-renames", NULL)) {
4801                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
4802                         return error("invalid argument to -M: %s", arg+2);
4803                 options->detect_rename = DIFF_DETECT_RENAME;
4804         }
4805         else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
4806                 options->irreversible_delete = 1;
4807         }
4808         else if (starts_with(arg, "-C") ||
4809                  skip_to_optional_arg(arg, "--find-copies", NULL)) {
4810                 if (options->detect_rename == DIFF_DETECT_COPY)
4811                         options->flags.find_copies_harder = 1;
4812                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
4813                         return error("invalid argument to -C: %s", arg+2);
4814                 options->detect_rename = DIFF_DETECT_COPY;
4815         }
4816         else if (!strcmp(arg, "--no-renames"))
4817                 options->detect_rename = 0;
4818         else if (!strcmp(arg, "--rename-empty"))
4819                 options->flags.rename_empty = 1;
4820         else if (!strcmp(arg, "--no-rename-empty"))
4821                 options->flags.rename_empty = 0;
4822         else if (skip_to_optional_arg_default(arg, "--relative", &arg, NULL)) {
4823                 options->flags.relative_name = 1;
4824                 if (arg)
4825                         options->prefix = arg;
4826         }
4827
4828         /* xdiff options */
4829         else if (!strcmp(arg, "--minimal"))
4830                 DIFF_XDL_SET(options, NEED_MINIMAL);
4831         else if (!strcmp(arg, "--no-minimal"))
4832                 DIFF_XDL_CLR(options, NEED_MINIMAL);
4833         else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
4834                 DIFF_XDL_SET(options, IGNORE_WHITESPACE);
4835         else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
4836                 DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
4837         else if (!strcmp(arg, "--ignore-space-at-eol"))
4838                 DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
4839         else if (!strcmp(arg, "--ignore-cr-at-eol"))
4840                 DIFF_XDL_SET(options, IGNORE_CR_AT_EOL);
4841         else if (!strcmp(arg, "--ignore-blank-lines"))
4842                 DIFF_XDL_SET(options, IGNORE_BLANK_LINES);
4843         else if (!strcmp(arg, "--indent-heuristic"))
4844                 DIFF_XDL_SET(options, INDENT_HEURISTIC);
4845         else if (!strcmp(arg, "--no-indent-heuristic"))
4846                 DIFF_XDL_CLR(options, INDENT_HEURISTIC);
4847         else if (!strcmp(arg, "--patience")) {
4848                 int i;
4849                 options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
4850                 /*
4851                  * Both --patience and --anchored use PATIENCE_DIFF
4852                  * internally, so remove any anchors previously
4853                  * specified.
4854                  */
4855                 for (i = 0; i < options->anchors_nr; i++)
4856                         free(options->anchors[i]);
4857                 options->anchors_nr = 0;
4858         } else if (!strcmp(arg, "--histogram"))
4859                 options->xdl_opts = DIFF_WITH_ALG(options, HISTOGRAM_DIFF);
4860         else if ((argcount = parse_long_opt("diff-algorithm", av, &optarg))) {
4861                 long value = parse_algorithm_value(optarg);
4862                 if (value < 0)
4863                         return error("option diff-algorithm accepts \"myers\", "
4864                                      "\"minimal\", \"patience\" and \"histogram\"");
4865                 /* clear out previous settings */
4866                 DIFF_XDL_CLR(options, NEED_MINIMAL);
4867                 options->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
4868                 options->xdl_opts |= value;
4869                 return argcount;
4870         } else if (skip_prefix(arg, "--anchored=", &arg)) {
4871                 options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
4872                 ALLOC_GROW(options->anchors, options->anchors_nr + 1,
4873                            options->anchors_alloc);
4874                 options->anchors[options->anchors_nr++] = xstrdup(arg);
4875         }
4876
4877         /* flags options */
4878         else if (!strcmp(arg, "--binary")) {
4879                 enable_patch_output(&options->output_format);
4880                 options->flags.binary = 1;
4881         }
4882         else if (!strcmp(arg, "--full-index"))
4883                 options->flags.full_index = 1;
4884         else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
4885                 options->flags.text = 1;
4886         else if (!strcmp(arg, "-R"))
4887                 options->flags.reverse_diff = 1;
4888         else if (!strcmp(arg, "--find-copies-harder"))
4889                 options->flags.find_copies_harder = 1;
4890         else if (!strcmp(arg, "--follow"))
4891                 options->flags.follow_renames = 1;
4892         else if (!strcmp(arg, "--no-follow")) {
4893                 options->flags.follow_renames = 0;
4894                 options->flags.default_follow_renames = 0;
4895         } else if (skip_to_optional_arg_default(arg, "--color", &arg, "always")) {
4896                 int value = git_config_colorbool(NULL, arg);
4897                 if (value < 0)
4898                         return error("option `color' expects \"always\", \"auto\", or \"never\"");
4899                 options->use_color = value;
4900         }
4901         else if (!strcmp(arg, "--no-color"))
4902                 options->use_color = 0;
4903         else if (!strcmp(arg, "--color-moved")) {
4904                 if (diff_color_moved_default)
4905                         options->color_moved = diff_color_moved_default;
4906                 if (options->color_moved == COLOR_MOVED_NO)
4907                         options->color_moved = COLOR_MOVED_DEFAULT;
4908         } else if (!strcmp(arg, "--no-color-moved"))
4909                 options->color_moved = COLOR_MOVED_NO;
4910         else if (skip_prefix(arg, "--color-moved=", &arg)) {
4911                 int cm = parse_color_moved(arg);
4912                 if (cm < 0)
4913                         die("bad --color-moved argument: %s", arg);
4914                 options->color_moved = cm;
4915         } else if (skip_prefix(arg, "--color-moved-ws=", &arg)) {
4916                 options->color_moved_ws_handling = parse_color_moved_ws(arg);
4917         } else if (skip_to_optional_arg_default(arg, "--color-words", &options->word_regex, NULL)) {
4918                 options->use_color = 1;
4919                 options->word_diff = DIFF_WORDS_COLOR;
4920         }
4921         else if (!strcmp(arg, "--word-diff")) {
4922                 if (options->word_diff == DIFF_WORDS_NONE)
4923                         options->word_diff = DIFF_WORDS_PLAIN;
4924         }
4925         else if (skip_prefix(arg, "--word-diff=", &arg)) {
4926                 if (!strcmp(arg, "plain"))
4927                         options->word_diff = DIFF_WORDS_PLAIN;
4928                 else if (!strcmp(arg, "color")) {
4929                         options->use_color = 1;
4930                         options->word_diff = DIFF_WORDS_COLOR;
4931                 }
4932                 else if (!strcmp(arg, "porcelain"))
4933                         options->word_diff = DIFF_WORDS_PORCELAIN;
4934                 else if (!strcmp(arg, "none"))
4935                         options->word_diff = DIFF_WORDS_NONE;
4936                 else
4937                         die("bad --word-diff argument: %s", arg);
4938         }
4939         else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
4940                 if (options->word_diff == DIFF_WORDS_NONE)
4941                         options->word_diff = DIFF_WORDS_PLAIN;
4942                 options->word_regex = optarg;
4943                 return argcount;
4944         }
4945         else if (!strcmp(arg, "--exit-code"))
4946                 options->flags.exit_with_status = 1;
4947         else if (!strcmp(arg, "--quiet"))
4948                 options->flags.quick = 1;
4949         else if (!strcmp(arg, "--ext-diff"))
4950                 options->flags.allow_external = 1;
4951         else if (!strcmp(arg, "--no-ext-diff"))
4952                 options->flags.allow_external = 0;
4953         else if (!strcmp(arg, "--textconv")) {
4954                 options->flags.allow_textconv = 1;
4955                 options->flags.textconv_set_via_cmdline = 1;
4956         } else if (!strcmp(arg, "--no-textconv"))
4957                 options->flags.allow_textconv = 0;
4958         else if (skip_to_optional_arg_default(arg, "--ignore-submodules", &arg, "all")) {
4959                 options->flags.override_submodule_config = 1;
4960                 handle_ignore_submodules_arg(options, arg);
4961         } else if (skip_to_optional_arg_default(arg, "--submodule", &arg, "log"))
4962                 return parse_submodule_opt(options, arg);
4963         else if (skip_prefix(arg, "--ws-error-highlight=", &arg))
4964                 return parse_ws_error_highlight_opt(options, arg);
4965         else if (!strcmp(arg, "--ita-invisible-in-index"))
4966                 options->ita_invisible_in_index = 1;
4967         else if (!strcmp(arg, "--ita-visible-in-index"))
4968                 options->ita_invisible_in_index = 0;
4969
4970         /* misc options */
4971         else if (!strcmp(arg, "-z"))
4972                 options->line_termination = 0;
4973         else if ((argcount = short_opt('l', av, &optarg))) {
4974                 options->rename_limit = strtoul(optarg, NULL, 10);
4975                 return argcount;
4976         }
4977         else if ((argcount = short_opt('S', av, &optarg))) {
4978                 options->pickaxe = optarg;
4979                 options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
4980                 return argcount;
4981         } else if ((argcount = short_opt('G', av, &optarg))) {
4982                 options->pickaxe = optarg;
4983                 options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
4984                 return argcount;
4985         }
4986         else if (!strcmp(arg, "--pickaxe-all"))
4987                 options->pickaxe_opts |= DIFF_PICKAXE_ALL;
4988         else if (!strcmp(arg, "--pickaxe-regex"))
4989                 options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
4990         else if ((argcount = short_opt('O', av, &optarg))) {
4991                 options->orderfile = prefix_filename(prefix, optarg);
4992                 return argcount;
4993         } else if (skip_prefix(arg, "--find-object=", &arg))
4994                 return parse_objfind_opt(options, arg);
4995         else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
4996                 int offending = parse_diff_filter_opt(optarg, options);
4997                 if (offending)
4998                         die("unknown change class '%c' in --diff-filter=%s",
4999                             offending, optarg);
5000                 return argcount;
5001         }
5002         else if (!strcmp(arg, "--no-abbrev"))
5003                 options->abbrev = 0;
5004         else if (!strcmp(arg, "--abbrev"))
5005                 options->abbrev = DEFAULT_ABBREV;
5006         else if (skip_prefix(arg, "--abbrev=", &arg)) {
5007                 options->abbrev = strtoul(arg, NULL, 10);
5008                 if (options->abbrev < MINIMUM_ABBREV)
5009                         options->abbrev = MINIMUM_ABBREV;
5010                 else if (the_hash_algo->hexsz < options->abbrev)
5011                         options->abbrev = the_hash_algo->hexsz;
5012         }
5013         else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
5014                 options->a_prefix = optarg;
5015                 return argcount;
5016         }
5017         else if ((argcount = parse_long_opt("line-prefix", av, &optarg))) {
5018                 options->line_prefix = optarg;
5019                 options->line_prefix_length = strlen(options->line_prefix);
5020                 graph_setup_line_prefix(options);
5021                 return argcount;
5022         }
5023         else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
5024                 options->b_prefix = optarg;
5025                 return argcount;
5026         }
5027         else if (!strcmp(arg, "--no-prefix"))
5028                 options->a_prefix = options->b_prefix = "";
5029         else if (opt_arg(arg, '\0', "inter-hunk-context",
5030                          &options->interhunkcontext))
5031                 ;
5032         else if (!strcmp(arg, "-W"))
5033                 options->flags.funccontext = 1;
5034         else if (!strcmp(arg, "--function-context"))
5035                 options->flags.funccontext = 1;
5036         else if (!strcmp(arg, "--no-function-context"))
5037                 options->flags.funccontext = 0;
5038         else if ((argcount = parse_long_opt("output", av, &optarg))) {
5039                 char *path = prefix_filename(prefix, optarg);
5040                 options->file = xfopen(path, "w");
5041                 options->close_file = 1;
5042                 if (options->use_color != GIT_COLOR_ALWAYS)
5043                         options->use_color = GIT_COLOR_NEVER;
5044                 free(path);
5045                 return argcount;
5046         } else
5047                 return 0;
5048         return 1;
5049 }
5050
5051 int parse_rename_score(const char **cp_p)
5052 {
5053         unsigned long num, scale;
5054         int ch, dot;
5055         const char *cp = *cp_p;
5056
5057         num = 0;
5058         scale = 1;
5059         dot = 0;
5060         for (;;) {
5061                 ch = *cp;
5062                 if ( !dot && ch == '.' ) {
5063                         scale = 1;
5064                         dot = 1;
5065                 } else if ( ch == '%' ) {
5066                         scale = dot ? scale*100 : 100;
5067                         cp++;   /* % is always at the end */
5068                         break;
5069                 } else if ( ch >= '0' && ch <= '9' ) {
5070                         if ( scale < 100000 ) {
5071                                 scale *= 10;
5072                                 num = (num*10) + (ch-'0');
5073                         }
5074                 } else {
5075                         break;
5076                 }
5077                 cp++;
5078         }
5079         *cp_p = cp;
5080
5081         /* user says num divided by scale and we say internally that
5082          * is MAX_SCORE * num / scale.
5083          */
5084         return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
5085 }
5086
5087 static int diff_scoreopt_parse(const char *opt)
5088 {
5089         int opt1, opt2, cmd;
5090
5091         if (*opt++ != '-')
5092                 return -1;
5093         cmd = *opt++;
5094         if (cmd == '-') {
5095                 /* convert the long-form arguments into short-form versions */
5096                 if (skip_prefix(opt, "break-rewrites", &opt)) {
5097                         if (*opt == 0 || *opt++ == '=')
5098                                 cmd = 'B';
5099                 } else if (skip_prefix(opt, "find-copies", &opt)) {
5100                         if (*opt == 0 || *opt++ == '=')
5101                                 cmd = 'C';
5102                 } else if (skip_prefix(opt, "find-renames", &opt)) {
5103                         if (*opt == 0 || *opt++ == '=')
5104                                 cmd = 'M';
5105                 }
5106         }
5107         if (cmd != 'M' && cmd != 'C' && cmd != 'B')
5108                 return -1; /* that is not a -M, -C, or -B option */
5109
5110         opt1 = parse_rename_score(&opt);
5111         if (cmd != 'B')
5112                 opt2 = 0;
5113         else {
5114                 if (*opt == 0)
5115                         opt2 = 0;
5116                 else if (*opt != '/')
5117                         return -1; /* we expect -B80/99 or -B80 */
5118                 else {
5119                         opt++;
5120                         opt2 = parse_rename_score(&opt);
5121                 }
5122         }
5123         if (*opt != 0)
5124                 return -1;
5125         return opt1 | (opt2 << 16);
5126 }
5127
5128 struct diff_queue_struct diff_queued_diff;
5129
5130 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
5131 {
5132         ALLOC_GROW(queue->queue, queue->nr + 1, queue->alloc);
5133         queue->queue[queue->nr++] = dp;
5134 }
5135
5136 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
5137                                  struct diff_filespec *one,
5138                                  struct diff_filespec *two)
5139 {
5140         struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
5141         dp->one = one;
5142         dp->two = two;
5143         if (queue)
5144                 diff_q(queue, dp);
5145         return dp;
5146 }
5147
5148 void diff_free_filepair(struct diff_filepair *p)
5149 {
5150         free_filespec(p->one);
5151         free_filespec(p->two);
5152         free(p);
5153 }
5154
5155 const char *diff_aligned_abbrev(const struct object_id *oid, int len)
5156 {
5157         int abblen;
5158         const char *abbrev;
5159
5160         /* Do we want all 40 hex characters? */
5161         if (len == the_hash_algo->hexsz)
5162                 return oid_to_hex(oid);
5163
5164         /* An abbreviated value is fine, possibly followed by an ellipsis. */
5165         abbrev = diff_abbrev_oid(oid, len);
5166
5167         if (!print_sha1_ellipsis())
5168                 return abbrev;
5169
5170         abblen = strlen(abbrev);
5171
5172         /*
5173          * In well-behaved cases, where the abbreviated result is the
5174          * same as the requested length, append three dots after the
5175          * abbreviation (hence the whole logic is limited to the case
5176          * where abblen < 37); when the actual abbreviated result is a
5177          * bit longer than the requested length, we reduce the number
5178          * of dots so that they match the well-behaved ones.  However,
5179          * if the actual abbreviation is longer than the requested
5180          * length by more than three, we give up on aligning, and add
5181          * three dots anyway, to indicate that the output is not the
5182          * full object name.  Yes, this may be suboptimal, but this
5183          * appears only in "diff --raw --abbrev" output and it is not
5184          * worth the effort to change it now.  Note that this would
5185          * likely to work fine when the automatic sizing of default
5186          * abbreviation length is used--we would be fed -1 in "len" in
5187          * that case, and will end up always appending three-dots, but
5188          * the automatic sizing is supposed to give abblen that ensures
5189          * uniqueness across all objects (statistically speaking).
5190          */
5191         if (abblen < the_hash_algo->hexsz - 3) {
5192                 static char hex[GIT_MAX_HEXSZ + 1];
5193                 if (len < abblen && abblen <= len + 2)
5194                         xsnprintf(hex, sizeof(hex), "%s%.*s", abbrev, len+3-abblen, "..");
5195                 else
5196                         xsnprintf(hex, sizeof(hex), "%s...", abbrev);
5197                 return hex;
5198         }
5199
5200         return oid_to_hex(oid);
5201 }
5202
5203 static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
5204 {
5205         int line_termination = opt->line_termination;
5206         int inter_name_termination = line_termination ? '\t' : '\0';
5207
5208         fprintf(opt->file, "%s", diff_line_prefix(opt));
5209         if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
5210                 fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
5211                         diff_aligned_abbrev(&p->one->oid, opt->abbrev));
5212                 fprintf(opt->file, "%s ",
5213                         diff_aligned_abbrev(&p->two->oid, opt->abbrev));
5214         }
5215         if (p->score) {
5216                 fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
5217                         inter_name_termination);
5218         } else {
5219                 fprintf(opt->file, "%c%c", p->status, inter_name_termination);
5220         }
5221
5222         if (p->status == DIFF_STATUS_COPIED ||
5223             p->status == DIFF_STATUS_RENAMED) {
5224                 const char *name_a, *name_b;
5225                 name_a = p->one->path;
5226                 name_b = p->two->path;
5227                 strip_prefix(opt->prefix_length, &name_a, &name_b);
5228                 write_name_quoted(name_a, opt->file, inter_name_termination);
5229                 write_name_quoted(name_b, opt->file, line_termination);
5230         } else {
5231                 const char *name_a, *name_b;
5232                 name_a = p->one->mode ? p->one->path : p->two->path;
5233                 name_b = NULL;
5234                 strip_prefix(opt->prefix_length, &name_a, &name_b);
5235                 write_name_quoted(name_a, opt->file, line_termination);
5236         }
5237 }
5238
5239 int diff_unmodified_pair(struct diff_filepair *p)
5240 {
5241         /* This function is written stricter than necessary to support
5242          * the currently implemented transformers, but the idea is to
5243          * let transformers to produce diff_filepairs any way they want,
5244          * and filter and clean them up here before producing the output.
5245          */
5246         struct diff_filespec *one = p->one, *two = p->two;
5247
5248         if (DIFF_PAIR_UNMERGED(p))
5249                 return 0; /* unmerged is interesting */
5250
5251         /* deletion, addition, mode or type change
5252          * and rename are all interesting.
5253          */
5254         if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
5255             DIFF_PAIR_MODE_CHANGED(p) ||
5256             strcmp(one->path, two->path))
5257                 return 0;
5258
5259         /* both are valid and point at the same path.  that is, we are
5260          * dealing with a change.
5261          */
5262         if (one->oid_valid && two->oid_valid &&
5263             !oidcmp(&one->oid, &two->oid) &&
5264             !one->dirty_submodule && !two->dirty_submodule)
5265                 return 1; /* no change */
5266         if (!one->oid_valid && !two->oid_valid)
5267                 return 1; /* both look at the same file on the filesystem. */
5268         return 0;
5269 }
5270
5271 static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
5272 {
5273         if (diff_unmodified_pair(p))
5274                 return;
5275
5276         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5277             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5278                 return; /* no tree diffs in patch format */
5279
5280         run_diff(p, o);
5281 }
5282
5283 static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
5284                             struct diffstat_t *diffstat)
5285 {
5286         if (diff_unmodified_pair(p))
5287                 return;
5288
5289         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5290             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5291                 return; /* no useful stat for tree diffs */
5292
5293         run_diffstat(p, o, diffstat);
5294 }
5295
5296 static void diff_flush_checkdiff(struct diff_filepair *p,
5297                 struct diff_options *o)
5298 {
5299         if (diff_unmodified_pair(p))
5300                 return;
5301
5302         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5303             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5304                 return; /* nothing to check in tree diffs */
5305
5306         run_checkdiff(p, o);
5307 }
5308
5309 int diff_queue_is_empty(void)
5310 {
5311         struct diff_queue_struct *q = &diff_queued_diff;
5312         int i;
5313         for (i = 0; i < q->nr; i++)
5314                 if (!diff_unmodified_pair(q->queue[i]))
5315                         return 0;
5316         return 1;
5317 }
5318
5319 #if DIFF_DEBUG
5320 void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
5321 {
5322         fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
5323                 x, one ? one : "",
5324                 s->path,
5325                 DIFF_FILE_VALID(s) ? "valid" : "invalid",
5326                 s->mode,
5327                 s->oid_valid ? oid_to_hex(&s->oid) : "");
5328         fprintf(stderr, "queue[%d] %s size %lu\n",
5329                 x, one ? one : "",
5330                 s->size);
5331 }
5332
5333 void diff_debug_filepair(const struct diff_filepair *p, int i)
5334 {
5335         diff_debug_filespec(p->one, i, "one");
5336         diff_debug_filespec(p->two, i, "two");
5337         fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
5338                 p->score, p->status ? p->status : '?',
5339                 p->one->rename_used, p->broken_pair);
5340 }
5341
5342 void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
5343 {
5344         int i;
5345         if (msg)
5346                 fprintf(stderr, "%s\n", msg);
5347         fprintf(stderr, "q->nr = %d\n", q->nr);
5348         for (i = 0; i < q->nr; i++) {
5349                 struct diff_filepair *p = q->queue[i];
5350                 diff_debug_filepair(p, i);
5351         }
5352 }
5353 #endif
5354
5355 static void diff_resolve_rename_copy(void)
5356 {
5357         int i;
5358         struct diff_filepair *p;
5359         struct diff_queue_struct *q = &diff_queued_diff;
5360
5361         diff_debug_queue("resolve-rename-copy", q);
5362
5363         for (i = 0; i < q->nr; i++) {
5364                 p = q->queue[i];
5365                 p->status = 0; /* undecided */
5366                 if (DIFF_PAIR_UNMERGED(p))
5367                         p->status = DIFF_STATUS_UNMERGED;
5368                 else if (!DIFF_FILE_VALID(p->one))
5369                         p->status = DIFF_STATUS_ADDED;
5370                 else if (!DIFF_FILE_VALID(p->two))
5371                         p->status = DIFF_STATUS_DELETED;
5372                 else if (DIFF_PAIR_TYPE_CHANGED(p))
5373                         p->status = DIFF_STATUS_TYPE_CHANGED;
5374
5375                 /* from this point on, we are dealing with a pair
5376                  * whose both sides are valid and of the same type, i.e.
5377                  * either in-place edit or rename/copy edit.
5378                  */
5379                 else if (DIFF_PAIR_RENAME(p)) {
5380                         /*
5381                          * A rename might have re-connected a broken
5382                          * pair up, causing the pathnames to be the
5383                          * same again. If so, that's not a rename at
5384                          * all, just a modification..
5385                          *
5386                          * Otherwise, see if this source was used for
5387                          * multiple renames, in which case we decrement
5388                          * the count, and call it a copy.
5389                          */
5390                         if (!strcmp(p->one->path, p->two->path))
5391                                 p->status = DIFF_STATUS_MODIFIED;
5392                         else if (--p->one->rename_used > 0)
5393                                 p->status = DIFF_STATUS_COPIED;
5394                         else
5395                                 p->status = DIFF_STATUS_RENAMED;
5396                 }
5397                 else if (oidcmp(&p->one->oid, &p->two->oid) ||
5398                          p->one->mode != p->two->mode ||
5399                          p->one->dirty_submodule ||
5400                          p->two->dirty_submodule ||
5401                          is_null_oid(&p->one->oid))
5402                         p->status = DIFF_STATUS_MODIFIED;
5403                 else {
5404                         /* This is a "no-change" entry and should not
5405                          * happen anymore, but prepare for broken callers.
5406                          */
5407                         error("feeding unmodified %s to diffcore",
5408                               p->one->path);
5409                         p->status = DIFF_STATUS_UNKNOWN;
5410                 }
5411         }
5412         diff_debug_queue("resolve-rename-copy done", q);
5413 }
5414
5415 static int check_pair_status(struct diff_filepair *p)
5416 {
5417         switch (p->status) {
5418         case DIFF_STATUS_UNKNOWN:
5419                 return 0;
5420         case 0:
5421                 die("internal error in diff-resolve-rename-copy");
5422         default:
5423                 return 1;
5424         }
5425 }
5426
5427 static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
5428 {
5429         int fmt = opt->output_format;
5430
5431         if (fmt & DIFF_FORMAT_CHECKDIFF)
5432                 diff_flush_checkdiff(p, opt);
5433         else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
5434                 diff_flush_raw(p, opt);
5435         else if (fmt & DIFF_FORMAT_NAME) {
5436                 const char *name_a, *name_b;
5437                 name_a = p->two->path;
5438                 name_b = NULL;
5439                 strip_prefix(opt->prefix_length, &name_a, &name_b);
5440                 fprintf(opt->file, "%s", diff_line_prefix(opt));
5441                 write_name_quoted(name_a, opt->file, opt->line_termination);
5442         }
5443 }
5444
5445 static void show_file_mode_name(struct diff_options *opt, const char *newdelete, struct diff_filespec *fs)
5446 {
5447         struct strbuf sb = STRBUF_INIT;
5448         if (fs->mode)
5449                 strbuf_addf(&sb, " %s mode %06o ", newdelete, fs->mode);
5450         else
5451                 strbuf_addf(&sb, " %s ", newdelete);
5452
5453         quote_c_style(fs->path, &sb, NULL, 0);
5454         strbuf_addch(&sb, '\n');
5455         emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5456                          sb.buf, sb.len, 0);
5457         strbuf_release(&sb);
5458 }
5459
5460 static void show_mode_change(struct diff_options *opt, struct diff_filepair *p,
5461                 int show_name)
5462 {
5463         if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
5464                 struct strbuf sb = STRBUF_INIT;
5465                 strbuf_addf(&sb, " mode change %06o => %06o",
5466                             p->one->mode, p->two->mode);
5467                 if (show_name) {
5468                         strbuf_addch(&sb, ' ');
5469                         quote_c_style(p->two->path, &sb, NULL, 0);
5470                 }
5471                 strbuf_addch(&sb, '\n');
5472                 emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5473                                  sb.buf, sb.len, 0);
5474                 strbuf_release(&sb);
5475         }
5476 }
5477
5478 static void show_rename_copy(struct diff_options *opt, const char *renamecopy,
5479                 struct diff_filepair *p)
5480 {
5481         struct strbuf sb = STRBUF_INIT;
5482         struct strbuf names = STRBUF_INIT;
5483
5484         pprint_rename(&names, p->one->path, p->two->path);
5485         strbuf_addf(&sb, " %s %s (%d%%)\n",
5486                     renamecopy, names.buf, similarity_index(p));
5487         strbuf_release(&names);
5488         emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5489                                  sb.buf, sb.len, 0);
5490         show_mode_change(opt, p, 0);
5491         strbuf_release(&sb);
5492 }
5493
5494 static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
5495 {
5496         switch(p->status) {
5497         case DIFF_STATUS_DELETED:
5498                 show_file_mode_name(opt, "delete", p->one);
5499                 break;
5500         case DIFF_STATUS_ADDED:
5501                 show_file_mode_name(opt, "create", p->two);
5502                 break;
5503         case DIFF_STATUS_COPIED:
5504                 show_rename_copy(opt, "copy", p);
5505                 break;
5506         case DIFF_STATUS_RENAMED:
5507                 show_rename_copy(opt, "rename", p);
5508                 break;
5509         default:
5510                 if (p->score) {
5511                         struct strbuf sb = STRBUF_INIT;
5512                         strbuf_addstr(&sb, " rewrite ");
5513                         quote_c_style(p->two->path, &sb, NULL, 0);
5514                         strbuf_addf(&sb, " (%d%%)\n", similarity_index(p));
5515                         emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5516                                          sb.buf, sb.len, 0);
5517                         strbuf_release(&sb);
5518                 }
5519                 show_mode_change(opt, p, !p->score);
5520                 break;
5521         }
5522 }
5523
5524 struct patch_id_t {
5525         git_SHA_CTX *ctx;
5526         int patchlen;
5527 };
5528
5529 static int remove_space(char *line, int len)
5530 {
5531         int i;
5532         char *dst = line;
5533         unsigned char c;
5534
5535         for (i = 0; i < len; i++)
5536                 if (!isspace((c = line[i])))
5537                         *dst++ = c;
5538
5539         return dst - line;
5540 }
5541
5542 static void patch_id_consume(void *priv, char *line, unsigned long len)
5543 {
5544         struct patch_id_t *data = priv;
5545         int new_len;
5546
5547         /* Ignore line numbers when computing the SHA1 of the patch */
5548         if (starts_with(line, "@@ -"))
5549                 return;
5550
5551         new_len = remove_space(line, len);
5552
5553         git_SHA1_Update(data->ctx, line, new_len);
5554         data->patchlen += new_len;
5555 }
5556
5557 static void patch_id_add_string(git_SHA_CTX *ctx, const char *str)
5558 {
5559         git_SHA1_Update(ctx, str, strlen(str));
5560 }
5561
5562 static void patch_id_add_mode(git_SHA_CTX *ctx, unsigned mode)
5563 {
5564         /* large enough for 2^32 in octal */
5565         char buf[12];
5566         int len = xsnprintf(buf, sizeof(buf), "%06o", mode);
5567         git_SHA1_Update(ctx, buf, len);
5568 }
5569
5570 /* returns 0 upon success, and writes result into sha1 */
5571 static int diff_get_patch_id(struct diff_options *options, struct object_id *oid, int diff_header_only)
5572 {
5573         struct diff_queue_struct *q = &diff_queued_diff;
5574         int i;
5575         git_SHA_CTX ctx;
5576         struct patch_id_t data;
5577
5578         git_SHA1_Init(&ctx);
5579         memset(&data, 0, sizeof(struct patch_id_t));
5580         data.ctx = &ctx;
5581
5582         for (i = 0; i < q->nr; i++) {
5583                 xpparam_t xpp;
5584                 xdemitconf_t xecfg;
5585                 mmfile_t mf1, mf2;
5586                 struct diff_filepair *p = q->queue[i];
5587                 int len1, len2;
5588
5589                 memset(&xpp, 0, sizeof(xpp));
5590                 memset(&xecfg, 0, sizeof(xecfg));
5591                 if (p->status == 0)
5592                         return error("internal diff status error");
5593                 if (p->status == DIFF_STATUS_UNKNOWN)
5594                         continue;
5595                 if (diff_unmodified_pair(p))
5596                         continue;
5597                 if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5598                     (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5599                         continue;
5600                 if (DIFF_PAIR_UNMERGED(p))
5601                         continue;
5602
5603                 diff_fill_oid_info(p->one);
5604                 diff_fill_oid_info(p->two);
5605
5606                 len1 = remove_space(p->one->path, strlen(p->one->path));
5607                 len2 = remove_space(p->two->path, strlen(p->two->path));
5608                 patch_id_add_string(&ctx, "diff--git");
5609                 patch_id_add_string(&ctx, "a/");
5610                 git_SHA1_Update(&ctx, p->one->path, len1);
5611                 patch_id_add_string(&ctx, "b/");
5612                 git_SHA1_Update(&ctx, p->two->path, len2);
5613
5614                 if (p->one->mode == 0) {
5615                         patch_id_add_string(&ctx, "newfilemode");
5616                         patch_id_add_mode(&ctx, p->two->mode);
5617                         patch_id_add_string(&ctx, "---/dev/null");
5618                         patch_id_add_string(&ctx, "+++b/");
5619                         git_SHA1_Update(&ctx, p->two->path, len2);
5620                 } else if (p->two->mode == 0) {
5621                         patch_id_add_string(&ctx, "deletedfilemode");
5622                         patch_id_add_mode(&ctx, p->one->mode);
5623                         patch_id_add_string(&ctx, "---a/");
5624                         git_SHA1_Update(&ctx, p->one->path, len1);
5625                         patch_id_add_string(&ctx, "+++/dev/null");
5626                 } else {
5627                         patch_id_add_string(&ctx, "---a/");
5628                         git_SHA1_Update(&ctx, p->one->path, len1);
5629                         patch_id_add_string(&ctx, "+++b/");
5630                         git_SHA1_Update(&ctx, p->two->path, len2);
5631                 }
5632
5633                 if (diff_header_only)
5634                         continue;
5635
5636                 if (fill_mmfile(&mf1, p->one) < 0 ||
5637                     fill_mmfile(&mf2, p->two) < 0)
5638                         return error("unable to read files to diff");
5639
5640                 if (diff_filespec_is_binary(p->one) ||
5641                     diff_filespec_is_binary(p->two)) {
5642                         git_SHA1_Update(&ctx, oid_to_hex(&p->one->oid),
5643                                         GIT_SHA1_HEXSZ);
5644                         git_SHA1_Update(&ctx, oid_to_hex(&p->two->oid),
5645                                         GIT_SHA1_HEXSZ);
5646                         continue;
5647                 }
5648
5649                 xpp.flags = 0;
5650                 xecfg.ctxlen = 3;
5651                 xecfg.flags = 0;
5652                 if (xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
5653                                   &xpp, &xecfg))
5654                         return error("unable to generate patch-id diff for %s",
5655                                      p->one->path);
5656         }
5657
5658         git_SHA1_Final(oid->hash, &ctx);
5659         return 0;
5660 }
5661
5662 int diff_flush_patch_id(struct diff_options *options, struct object_id *oid, int diff_header_only)
5663 {
5664         struct diff_queue_struct *q = &diff_queued_diff;
5665         int i;
5666         int result = diff_get_patch_id(options, oid, diff_header_only);
5667
5668         for (i = 0; i < q->nr; i++)
5669                 diff_free_filepair(q->queue[i]);
5670
5671         free(q->queue);
5672         DIFF_QUEUE_CLEAR(q);
5673
5674         return result;
5675 }
5676
5677 static int is_summary_empty(const struct diff_queue_struct *q)
5678 {
5679         int i;
5680
5681         for (i = 0; i < q->nr; i++) {
5682                 const struct diff_filepair *p = q->queue[i];
5683
5684                 switch (p->status) {
5685                 case DIFF_STATUS_DELETED:
5686                 case DIFF_STATUS_ADDED:
5687                 case DIFF_STATUS_COPIED:
5688                 case DIFF_STATUS_RENAMED:
5689                         return 0;
5690                 default:
5691                         if (p->score)
5692                                 return 0;
5693                         if (p->one->mode && p->two->mode &&
5694                             p->one->mode != p->two->mode)
5695                                 return 0;
5696                         break;
5697                 }
5698         }
5699         return 1;
5700 }
5701
5702 static const char rename_limit_warning[] =
5703 N_("inexact rename detection was skipped due to too many files.");
5704
5705 static const char degrade_cc_to_c_warning[] =
5706 N_("only found copies from modified paths due to too many files.");
5707
5708 static const char rename_limit_advice[] =
5709 N_("you may want to set your %s variable to at least "
5710    "%d and retry the command.");
5711
5712 void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
5713 {
5714         fflush(stdout);
5715         if (degraded_cc)
5716                 warning(_(degrade_cc_to_c_warning));
5717         else if (needed)
5718                 warning(_(rename_limit_warning));
5719         else
5720                 return;
5721         if (0 < needed)
5722                 warning(_(rename_limit_advice), varname, needed);
5723 }
5724
5725 static void diff_flush_patch_all_file_pairs(struct diff_options *o)
5726 {
5727         int i;
5728         static struct emitted_diff_symbols esm = EMITTED_DIFF_SYMBOLS_INIT;
5729         struct diff_queue_struct *q = &diff_queued_diff;
5730
5731         if (WSEH_NEW & WS_RULE_MASK)
5732                 BUG("WS rules bit mask overlaps with diff symbol flags");
5733
5734         if (o->color_moved)
5735                 o->emitted_symbols = &esm;
5736
5737         for (i = 0; i < q->nr; i++) {
5738                 struct diff_filepair *p = q->queue[i];
5739                 if (check_pair_status(p))
5740                         diff_flush_patch(p, o);
5741         }
5742
5743         if (o->emitted_symbols) {
5744                 if (o->color_moved) {
5745                         struct hashmap add_lines, del_lines;
5746
5747                         if (o->color_moved_ws_handling &
5748                             COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE)
5749                                 o->color_moved_ws_handling |= XDF_IGNORE_WHITESPACE;
5750
5751                         hashmap_init(&del_lines, moved_entry_cmp, o, 0);
5752                         hashmap_init(&add_lines, moved_entry_cmp, o, 0);
5753
5754                         add_lines_to_move_detection(o, &add_lines, &del_lines);
5755                         mark_color_as_moved(o, &add_lines, &del_lines);
5756                         if (o->color_moved == COLOR_MOVED_ZEBRA_DIM)
5757                                 dim_moved_lines(o);
5758
5759                         hashmap_free(&add_lines, 0);
5760                         hashmap_free(&del_lines, 0);
5761                 }
5762
5763                 for (i = 0; i < esm.nr; i++)
5764                         emit_diff_symbol_from_struct(o, &esm.buf[i]);
5765
5766                 for (i = 0; i < esm.nr; i++)
5767                         free((void *)esm.buf[i].line);
5768         }
5769         esm.nr = 0;
5770 }
5771
5772 void diff_flush(struct diff_options *options)
5773 {
5774         struct diff_queue_struct *q = &diff_queued_diff;
5775         int i, output_format = options->output_format;
5776         int separator = 0;
5777         int dirstat_by_line = 0;
5778
5779         /*
5780          * Order: raw, stat, summary, patch
5781          * or:    name/name-status/checkdiff (other bits clear)
5782          */
5783         if (!q->nr)
5784                 goto free_queue;
5785
5786         if (output_format & (DIFF_FORMAT_RAW |
5787                              DIFF_FORMAT_NAME |
5788                              DIFF_FORMAT_NAME_STATUS |
5789                              DIFF_FORMAT_CHECKDIFF)) {
5790                 for (i = 0; i < q->nr; i++) {
5791                         struct diff_filepair *p = q->queue[i];
5792                         if (check_pair_status(p))
5793                                 flush_one_pair(p, options);
5794                 }
5795                 separator++;
5796         }
5797
5798         if (output_format & DIFF_FORMAT_DIRSTAT && options->flags.dirstat_by_line)
5799                 dirstat_by_line = 1;
5800
5801         if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
5802             dirstat_by_line) {
5803                 struct diffstat_t diffstat;
5804
5805                 memset(&diffstat, 0, sizeof(struct diffstat_t));
5806                 for (i = 0; i < q->nr; i++) {
5807                         struct diff_filepair *p = q->queue[i];
5808                         if (check_pair_status(p))
5809                                 diff_flush_stat(p, options, &diffstat);
5810                 }
5811                 if (output_format & DIFF_FORMAT_NUMSTAT)
5812                         show_numstat(&diffstat, options);
5813                 if (output_format & DIFF_FORMAT_DIFFSTAT)
5814                         show_stats(&diffstat, options);
5815                 if (output_format & DIFF_FORMAT_SHORTSTAT)
5816                         show_shortstats(&diffstat, options);
5817                 if (output_format & DIFF_FORMAT_DIRSTAT && dirstat_by_line)
5818                         show_dirstat_by_line(&diffstat, options);
5819                 free_diffstat_info(&diffstat);
5820                 separator++;
5821         }
5822         if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
5823                 show_dirstat(options);
5824
5825         if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
5826                 for (i = 0; i < q->nr; i++) {
5827                         diff_summary(options, q->queue[i]);
5828                 }
5829                 separator++;
5830         }
5831
5832         if (output_format & DIFF_FORMAT_NO_OUTPUT &&
5833             options->flags.exit_with_status &&
5834             options->flags.diff_from_contents) {
5835                 /*
5836                  * run diff_flush_patch for the exit status. setting
5837                  * options->file to /dev/null should be safe, because we
5838                  * aren't supposed to produce any output anyway.
5839                  */
5840                 if (options->close_file)
5841                         fclose(options->file);
5842                 options->file = xfopen("/dev/null", "w");
5843                 options->close_file = 1;
5844                 options->color_moved = 0;
5845                 for (i = 0; i < q->nr; i++) {
5846                         struct diff_filepair *p = q->queue[i];
5847                         if (check_pair_status(p))
5848                                 diff_flush_patch(p, options);
5849                         if (options->found_changes)
5850                                 break;
5851                 }
5852         }
5853
5854         if (output_format & DIFF_FORMAT_PATCH) {
5855                 if (separator) {
5856                         emit_diff_symbol(options, DIFF_SYMBOL_SEPARATOR, NULL, 0, 0);
5857                         if (options->stat_sep)
5858                                 /* attach patch instead of inline */
5859                                 emit_diff_symbol(options, DIFF_SYMBOL_STAT_SEP,
5860                                                  NULL, 0, 0);
5861                 }
5862
5863                 diff_flush_patch_all_file_pairs(options);
5864         }
5865
5866         if (output_format & DIFF_FORMAT_CALLBACK)
5867                 options->format_callback(q, options, options->format_callback_data);
5868
5869         for (i = 0; i < q->nr; i++)
5870                 diff_free_filepair(q->queue[i]);
5871 free_queue:
5872         free(q->queue);
5873         DIFF_QUEUE_CLEAR(q);
5874         if (options->close_file)
5875                 fclose(options->file);
5876
5877         /*
5878          * Report the content-level differences with HAS_CHANGES;
5879          * diff_addremove/diff_change does not set the bit when
5880          * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
5881          */
5882         if (options->flags.diff_from_contents) {
5883                 if (options->found_changes)
5884                         options->flags.has_changes = 1;
5885                 else
5886                         options->flags.has_changes = 0;
5887         }
5888 }
5889
5890 static int match_filter(const struct diff_options *options, const struct diff_filepair *p)
5891 {
5892         return (((p->status == DIFF_STATUS_MODIFIED) &&
5893                  ((p->score &&
5894                    filter_bit_tst(DIFF_STATUS_FILTER_BROKEN, options)) ||
5895                   (!p->score &&
5896                    filter_bit_tst(DIFF_STATUS_MODIFIED, options)))) ||
5897                 ((p->status != DIFF_STATUS_MODIFIED) &&
5898                  filter_bit_tst(p->status, options)));
5899 }
5900
5901 static void diffcore_apply_filter(struct diff_options *options)
5902 {
5903         int i;
5904         struct diff_queue_struct *q = &diff_queued_diff;
5905         struct diff_queue_struct outq;
5906
5907         DIFF_QUEUE_CLEAR(&outq);
5908
5909         if (!options->filter)
5910                 return;
5911
5912         if (filter_bit_tst(DIFF_STATUS_FILTER_AON, options)) {
5913                 int found;
5914                 for (i = found = 0; !found && i < q->nr; i++) {
5915                         if (match_filter(options, q->queue[i]))
5916                                 found++;
5917                 }
5918                 if (found)
5919                         return;
5920
5921                 /* otherwise we will clear the whole queue
5922                  * by copying the empty outq at the end of this
5923                  * function, but first clear the current entries
5924                  * in the queue.
5925                  */
5926                 for (i = 0; i < q->nr; i++)
5927                         diff_free_filepair(q->queue[i]);
5928         }
5929         else {
5930                 /* Only the matching ones */
5931                 for (i = 0; i < q->nr; i++) {
5932                         struct diff_filepair *p = q->queue[i];
5933                         if (match_filter(options, p))
5934                                 diff_q(&outq, p);
5935                         else
5936                                 diff_free_filepair(p);
5937                 }
5938         }
5939         free(q->queue);
5940         *q = outq;
5941 }
5942
5943 /* Check whether two filespecs with the same mode and size are identical */
5944 static int diff_filespec_is_identical(struct diff_filespec *one,
5945                                       struct diff_filespec *two)
5946 {
5947         if (S_ISGITLINK(one->mode))
5948                 return 0;
5949         if (diff_populate_filespec(one, 0))
5950                 return 0;
5951         if (diff_populate_filespec(two, 0))
5952                 return 0;
5953         return !memcmp(one->data, two->data, one->size);
5954 }
5955
5956 static int diff_filespec_check_stat_unmatch(struct diff_filepair *p)
5957 {
5958         if (p->done_skip_stat_unmatch)
5959                 return p->skip_stat_unmatch_result;
5960
5961         p->done_skip_stat_unmatch = 1;
5962         p->skip_stat_unmatch_result = 0;
5963         /*
5964          * 1. Entries that come from stat info dirtiness
5965          *    always have both sides (iow, not create/delete),
5966          *    one side of the object name is unknown, with
5967          *    the same mode and size.  Keep the ones that
5968          *    do not match these criteria.  They have real
5969          *    differences.
5970          *
5971          * 2. At this point, the file is known to be modified,
5972          *    with the same mode and size, and the object
5973          *    name of one side is unknown.  Need to inspect
5974          *    the identical contents.
5975          */
5976         if (!DIFF_FILE_VALID(p->one) || /* (1) */
5977             !DIFF_FILE_VALID(p->two) ||
5978             (p->one->oid_valid && p->two->oid_valid) ||
5979             (p->one->mode != p->two->mode) ||
5980             diff_populate_filespec(p->one, CHECK_SIZE_ONLY) ||
5981             diff_populate_filespec(p->two, CHECK_SIZE_ONLY) ||
5982             (p->one->size != p->two->size) ||
5983             !diff_filespec_is_identical(p->one, p->two)) /* (2) */
5984                 p->skip_stat_unmatch_result = 1;
5985         return p->skip_stat_unmatch_result;
5986 }
5987
5988 static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
5989 {
5990         int i;
5991         struct diff_queue_struct *q = &diff_queued_diff;
5992         struct diff_queue_struct outq;
5993         DIFF_QUEUE_CLEAR(&outq);
5994
5995         for (i = 0; i < q->nr; i++) {
5996                 struct diff_filepair *p = q->queue[i];
5997
5998                 if (diff_filespec_check_stat_unmatch(p))
5999                         diff_q(&outq, p);
6000                 else {
6001                         /*
6002                          * The caller can subtract 1 from skip_stat_unmatch
6003                          * to determine how many paths were dirty only
6004                          * due to stat info mismatch.
6005                          */
6006                         if (!diffopt->flags.no_index)
6007                                 diffopt->skip_stat_unmatch++;
6008                         diff_free_filepair(p);
6009                 }
6010         }
6011         free(q->queue);
6012         *q = outq;
6013 }
6014
6015 static int diffnamecmp(const void *a_, const void *b_)
6016 {
6017         const struct diff_filepair *a = *((const struct diff_filepair **)a_);
6018         const struct diff_filepair *b = *((const struct diff_filepair **)b_);
6019         const char *name_a, *name_b;
6020
6021         name_a = a->one ? a->one->path : a->two->path;
6022         name_b = b->one ? b->one->path : b->two->path;
6023         return strcmp(name_a, name_b);
6024 }
6025
6026 void diffcore_fix_diff_index(struct diff_options *options)
6027 {
6028         struct diff_queue_struct *q = &diff_queued_diff;
6029         QSORT(q->queue, q->nr, diffnamecmp);
6030 }
6031
6032 void diffcore_std(struct diff_options *options)
6033 {
6034         /* NOTE please keep the following in sync with diff_tree_combined() */
6035         if (options->skip_stat_unmatch)
6036                 diffcore_skip_stat_unmatch(options);
6037         if (!options->found_follow) {
6038                 /* See try_to_follow_renames() in tree-diff.c */
6039                 if (options->break_opt != -1)
6040                         diffcore_break(options->break_opt);
6041                 if (options->detect_rename)
6042                         diffcore_rename(options);
6043                 if (options->break_opt != -1)
6044                         diffcore_merge_broken();
6045         }
6046         if (options->pickaxe_opts & DIFF_PICKAXE_KINDS_MASK)
6047                 diffcore_pickaxe(options);
6048         if (options->orderfile)
6049                 diffcore_order(options->orderfile);
6050         if (!options->found_follow)
6051                 /* See try_to_follow_renames() in tree-diff.c */
6052                 diff_resolve_rename_copy();
6053         diffcore_apply_filter(options);
6054
6055         if (diff_queued_diff.nr && !options->flags.diff_from_contents)
6056                 options->flags.has_changes = 1;
6057         else
6058                 options->flags.has_changes = 0;
6059
6060         options->found_follow = 0;
6061 }
6062
6063 int diff_result_code(struct diff_options *opt, int status)
6064 {
6065         int result = 0;
6066
6067         diff_warn_rename_limit("diff.renameLimit",
6068                                opt->needed_rename_limit,
6069                                opt->degraded_cc_to_c);
6070         if (!opt->flags.exit_with_status &&
6071             !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
6072                 return status;
6073         if (opt->flags.exit_with_status &&
6074             opt->flags.has_changes)
6075                 result |= 01;
6076         if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
6077             opt->flags.check_failed)
6078                 result |= 02;
6079         return result;
6080 }
6081
6082 int diff_can_quit_early(struct diff_options *opt)
6083 {
6084         return (opt->flags.quick &&
6085                 !opt->filter &&
6086                 opt->flags.has_changes);
6087 }
6088
6089 /*
6090  * Shall changes to this submodule be ignored?
6091  *
6092  * Submodule changes can be configured to be ignored separately for each path,
6093  * but that configuration can be overridden from the command line.
6094  */
6095 static int is_submodule_ignored(const char *path, struct diff_options *options)
6096 {
6097         int ignored = 0;
6098         struct diff_flags orig_flags = options->flags;
6099         if (!options->flags.override_submodule_config)
6100                 set_diffopt_flags_from_submodule_config(options, path);
6101         if (options->flags.ignore_submodules)
6102                 ignored = 1;
6103         options->flags = orig_flags;
6104         return ignored;
6105 }
6106
6107 void diff_addremove(struct diff_options *options,
6108                     int addremove, unsigned mode,
6109                     const struct object_id *oid,
6110                     int oid_valid,
6111                     const char *concatpath, unsigned dirty_submodule)
6112 {
6113         struct diff_filespec *one, *two;
6114
6115         if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
6116                 return;
6117
6118         /* This may look odd, but it is a preparation for
6119          * feeding "there are unchanged files which should
6120          * not produce diffs, but when you are doing copy
6121          * detection you would need them, so here they are"
6122          * entries to the diff-core.  They will be prefixed
6123          * with something like '=' or '*' (I haven't decided
6124          * which but should not make any difference).
6125          * Feeding the same new and old to diff_change()
6126          * also has the same effect.
6127          * Before the final output happens, they are pruned after
6128          * merged into rename/copy pairs as appropriate.
6129          */
6130         if (options->flags.reverse_diff)
6131                 addremove = (addremove == '+' ? '-' :
6132                              addremove == '-' ? '+' : addremove);
6133
6134         if (options->prefix &&
6135             strncmp(concatpath, options->prefix, options->prefix_length))
6136                 return;
6137
6138         one = alloc_filespec(concatpath);
6139         two = alloc_filespec(concatpath);
6140
6141         if (addremove != '+')
6142                 fill_filespec(one, oid, oid_valid, mode);
6143         if (addremove != '-') {
6144                 fill_filespec(two, oid, oid_valid, mode);
6145                 two->dirty_submodule = dirty_submodule;
6146         }
6147
6148         diff_queue(&diff_queued_diff, one, two);
6149         if (!options->flags.diff_from_contents)
6150                 options->flags.has_changes = 1;
6151 }
6152
6153 void diff_change(struct diff_options *options,
6154                  unsigned old_mode, unsigned new_mode,
6155                  const struct object_id *old_oid,
6156                  const struct object_id *new_oid,
6157                  int old_oid_valid, int new_oid_valid,
6158                  const char *concatpath,
6159                  unsigned old_dirty_submodule, unsigned new_dirty_submodule)
6160 {
6161         struct diff_filespec *one, *two;
6162         struct diff_filepair *p;
6163
6164         if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
6165             is_submodule_ignored(concatpath, options))
6166                 return;
6167
6168         if (options->flags.reverse_diff) {
6169                 SWAP(old_mode, new_mode);
6170                 SWAP(old_oid, new_oid);
6171                 SWAP(old_oid_valid, new_oid_valid);
6172                 SWAP(old_dirty_submodule, new_dirty_submodule);
6173         }
6174
6175         if (options->prefix &&
6176             strncmp(concatpath, options->prefix, options->prefix_length))
6177                 return;
6178
6179         one = alloc_filespec(concatpath);
6180         two = alloc_filespec(concatpath);
6181         fill_filespec(one, old_oid, old_oid_valid, old_mode);
6182         fill_filespec(two, new_oid, new_oid_valid, new_mode);
6183         one->dirty_submodule = old_dirty_submodule;
6184         two->dirty_submodule = new_dirty_submodule;
6185         p = diff_queue(&diff_queued_diff, one, two);
6186
6187         if (options->flags.diff_from_contents)
6188                 return;
6189
6190         if (options->flags.quick && options->skip_stat_unmatch &&
6191             !diff_filespec_check_stat_unmatch(p))
6192                 return;
6193
6194         options->flags.has_changes = 1;
6195 }
6196
6197 struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
6198 {
6199         struct diff_filepair *pair;
6200         struct diff_filespec *one, *two;
6201
6202         if (options->prefix &&
6203             strncmp(path, options->prefix, options->prefix_length))
6204                 return NULL;
6205
6206         one = alloc_filespec(path);
6207         two = alloc_filespec(path);
6208         pair = diff_queue(&diff_queued_diff, one, two);
6209         pair->is_unmerged = 1;
6210         return pair;
6211 }
6212
6213 static char *run_textconv(const char *pgm, struct diff_filespec *spec,
6214                 size_t *outsize)
6215 {
6216         struct diff_tempfile *temp;
6217         const char *argv[3];
6218         const char **arg = argv;
6219         struct child_process child = CHILD_PROCESS_INIT;
6220         struct strbuf buf = STRBUF_INIT;
6221         int err = 0;
6222
6223         temp = prepare_temp_file(spec->path, spec);
6224         *arg++ = pgm;
6225         *arg++ = temp->name;
6226         *arg = NULL;
6227
6228         child.use_shell = 1;
6229         child.argv = argv;
6230         child.out = -1;
6231         if (start_command(&child)) {
6232                 remove_tempfile();
6233                 return NULL;
6234         }
6235
6236         if (strbuf_read(&buf, child.out, 0) < 0)
6237                 err = error("error reading from textconv command '%s'", pgm);
6238         close(child.out);
6239
6240         if (finish_command(&child) || err) {
6241                 strbuf_release(&buf);
6242                 remove_tempfile();
6243                 return NULL;
6244         }
6245         remove_tempfile();
6246
6247         return strbuf_detach(&buf, outsize);
6248 }
6249
6250 size_t fill_textconv(struct userdiff_driver *driver,
6251                      struct diff_filespec *df,
6252                      char **outbuf)
6253 {
6254         size_t size;
6255
6256         if (!driver) {
6257                 if (!DIFF_FILE_VALID(df)) {
6258                         *outbuf = "";
6259                         return 0;
6260                 }
6261                 if (diff_populate_filespec(df, 0))
6262                         die("unable to read files to diff");
6263                 *outbuf = df->data;
6264                 return df->size;
6265         }
6266
6267         if (!driver->textconv)
6268                 BUG("fill_textconv called with non-textconv driver");
6269
6270         if (driver->textconv_cache && df->oid_valid) {
6271                 *outbuf = notes_cache_get(driver->textconv_cache,
6272                                           &df->oid,
6273                                           &size);
6274                 if (*outbuf)
6275                         return size;
6276         }
6277
6278         *outbuf = run_textconv(driver->textconv, df, &size);
6279         if (!*outbuf)
6280                 die("unable to read files to diff");
6281
6282         if (driver->textconv_cache && df->oid_valid) {
6283                 /* ignore errors, as we might be in a readonly repository */
6284                 notes_cache_put(driver->textconv_cache, &df->oid, *outbuf,
6285                                 size);
6286                 /*
6287                  * we could save up changes and flush them all at the end,
6288                  * but we would need an extra call after all diffing is done.
6289                  * Since generating a cache entry is the slow path anyway,
6290                  * this extra overhead probably isn't a big deal.
6291                  */
6292                 notes_cache_write(driver->textconv_cache);
6293         }
6294
6295         return size;
6296 }
6297
6298 int textconv_object(const char *path,
6299                     unsigned mode,
6300                     const struct object_id *oid,
6301                     int oid_valid,
6302                     char **buf,
6303                     unsigned long *buf_size)
6304 {
6305         struct diff_filespec *df;
6306         struct userdiff_driver *textconv;
6307
6308         df = alloc_filespec(path);
6309         fill_filespec(df, oid, oid_valid, mode);
6310         textconv = get_textconv(df);
6311         if (!textconv) {
6312                 free_filespec(df);
6313                 return 0;
6314         }
6315
6316         *buf_size = fill_textconv(textconv, df, buf);
6317         free_filespec(df);
6318         return 1;
6319 }
6320
6321 void setup_diff_pager(struct diff_options *opt)
6322 {
6323         /*
6324          * If the user asked for our exit code, then either they want --quiet
6325          * or --exit-code. We should definitely not bother with a pager in the
6326          * former case, as we will generate no output. Since we still properly
6327          * report our exit code even when a pager is run, we _could_ run a
6328          * pager with --exit-code. But since we have not done so historically,
6329          * and because it is easy to find people oneline advising "git diff
6330          * --exit-code" in hooks and other scripts, we do not do so.
6331          */
6332         if (!opt->flags.exit_with_status &&
6333             check_pager_config("diff") != 0)
6334                 setup_pager();
6335 }