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         GIT_COLOR_FAINT,        /* CONTEXT_DIM */
  74         GIT_COLOR_FAINT_RED,    /* OLD_DIM */
  75         GIT_COLOR_FAINT_GREEN,  /* NEW_DIM */
  76         GIT_COLOR_BOLD,         /* CONTEXT_BOLD */
  77         GIT_COLOR_BOLD_RED,     /* OLD_BOLD */
  78         GIT_COLOR_BOLD_GREEN,   /* NEW_BOLD */
  79 };
  80
  81 static const char *color_diff_slots[] = {
  82         [DIFF_CONTEXT]                = "context",
  83         [DIFF_METAINFO]               = "meta",
  84         [DIFF_FRAGINFO]               = "frag",
  85         [DIFF_FILE_OLD]               = "old",
  86         [DIFF_FILE_NEW]               = "new",
  87         [DIFF_COMMIT]                 = "commit",
  88         [DIFF_WHITESPACE]             = "whitespace",
  89         [DIFF_FUNCINFO]               = "func",
  90         [DIFF_FILE_OLD_MOVED]         = "oldMoved",
  91         [DIFF_FILE_OLD_MOVED_ALT]     = "oldMovedAlternative",
  92         [DIFF_FILE_OLD_MOVED_DIM]     = "oldMovedDimmed",
  93         [DIFF_FILE_OLD_MOVED_ALT_DIM] = "oldMovedAlternativeDimmed",
  94         [DIFF_FILE_NEW_MOVED]         = "newMoved",
  95         [DIFF_FILE_NEW_MOVED_ALT]     = "newMovedAlternative",
  96         [DIFF_FILE_NEW_MOVED_DIM]     = "newMovedDimmed",
  97         [DIFF_FILE_NEW_MOVED_ALT_DIM] = "newMovedAlternativeDimmed",
  98         [DIFF_CONTEXT_DIM]            = "contextDimmed",
  99         [DIFF_FILE_OLD_DIM]           = "oldDimmed",
 100         [DIFF_FILE_NEW_DIM]           = "newDimmed",
 101         [DIFF_CONTEXT_BOLD]           = "contextBold",
 102         [DIFF_FILE_OLD_BOLD]          = "oldBold",
 103         [DIFF_FILE_NEW_BOLD]          = "newBold",
 104 };
 105
 106 static NORETURN void die_want_option(const char *option_name)
 107 {
 108         die(_("option '%s' requires a value"), option_name);
 109 }
 110
 111 define_list_config_array_extra(color_diff_slots, {"plain"});
 112
 113 static int parse_diff_color_slot(const char *var)
 114 {
 115         if (!strcasecmp(var, "plain"))
 116                 return DIFF_CONTEXT;
 117         return LOOKUP_CONFIG(color_diff_slots, var);
 118 }
 119
 120 static int parse_dirstat_params(struct diff_options *options, const char *params_string,
 121                                 struct strbuf *errmsg)
 122 {
 123         char *params_copy = xstrdup(params_string);
 124         struct string_list params = STRING_LIST_INIT_NODUP;
 125         int ret = 0;
 126         int i;
 127
 128         if (*params_copy)
 129                 string_list_split_in_place(&params, params_copy, ',', -1);
 130         for (i = 0; i < params.nr; i++) {
 131                 const char *p = params.items[i].string;
 132                 if (!strcmp(p, "changes")) {
 133                         options->flags.dirstat_by_line = 0;
 134                         options->flags.dirstat_by_file = 0;
 135                 } else if (!strcmp(p, "lines")) {
 136                         options->flags.dirstat_by_line = 1;
 137                         options->flags.dirstat_by_file = 0;
 138                 } else if (!strcmp(p, "files")) {
 139                         options->flags.dirstat_by_line = 0;
 140                         options->flags.dirstat_by_file = 1;
 141                 } else if (!strcmp(p, "noncumulative")) {
 142                         options->flags.dirstat_cumulative = 0;
 143                 } else if (!strcmp(p, "cumulative")) {
 144                         options->flags.dirstat_cumulative = 1;
 145                 } else if (isdigit(*p)) {
 146                         char *end;
 147                         int permille = strtoul(p, &end, 10) * 10;
 148                         if (*end == '.' && isdigit(*++end)) {
 149                                 /* only use first digit */
 150                                 permille += *end - '0';
 151                                 /* .. and ignore any further digits */
 152                                 while (isdigit(*++end))
 153                                         ; /* nothing */
 154                         }
 155                         if (!*end)
 156                                 options->dirstat_permille = permille;
 157                         else {
 158                                 strbuf_addf(errmsg, _("  Failed to parse dirstat cut-off percentage '%s'\n"),
 159                                             p);
 160                                 ret++;
 161                         }
 162                 } else {
 163                         strbuf_addf(errmsg, _("  Unknown dirstat parameter '%s'\n"), p);
 164                         ret++;
 165                 }
 166
 167         }
 168         string_list_clear(&params, 0);
 169         free(params_copy);
 170         return ret;
 171 }
 172
 173 static int parse_submodule_params(struct diff_options *options, const char *value)
 174 {
 175         if (!strcmp(value, "log"))
 176                 options->submodule_format = DIFF_SUBMODULE_LOG;
 177         else if (!strcmp(value, "short"))
 178                 options->submodule_format = DIFF_SUBMODULE_SHORT;
 179         else if (!strcmp(value, "diff"))
 180                 options->submodule_format = DIFF_SUBMODULE_INLINE_DIFF;
 181         else
 182                 return -1;
 183         return 0;
 184 }
 185
 186 int git_config_rename(const char *var, const char *value)
 187 {
 188         if (!value)
 189                 return DIFF_DETECT_RENAME;
 190         if (!strcasecmp(value, "copies") || !strcasecmp(value, "copy"))
 191                 return  DIFF_DETECT_COPY;
 192         return git_config_bool(var,value) ? DIFF_DETECT_RENAME : 0;
 193 }
 194
 195 long parse_algorithm_value(const char *value)
 196 {
 197         if (!value)
 198                 return -1;
 199         else if (!strcasecmp(value, "myers") || !strcasecmp(value, "default"))
 200                 return 0;
 201         else if (!strcasecmp(value, "minimal"))
 202                 return XDF_NEED_MINIMAL;
 203         else if (!strcasecmp(value, "patience"))
 204                 return XDF_PATIENCE_DIFF;
 205         else if (!strcasecmp(value, "histogram"))
 206                 return XDF_HISTOGRAM_DIFF;
 207         return -1;
 208 }
 209
 210 static int parse_one_token(const char **arg, const char *token)
 211 {
 212         const char *rest;
 213         if (skip_prefix(*arg, token, &rest) && (!*rest || *rest == ',')) {
 214                 *arg = rest;
 215                 return 1;
 216         }
 217         return 0;
 218 }
 219
 220 static int parse_ws_error_highlight(const char *arg)
 221 {
 222         const char *orig_arg = arg;
 223         unsigned val = 0;
 224
 225         while (*arg) {
 226                 if (parse_one_token(&arg, "none"))
 227                         val = 0;
 228                 else if (parse_one_token(&arg, "default"))
 229                         val = WSEH_NEW;
 230                 else if (parse_one_token(&arg, "all"))
 231                         val = WSEH_NEW | WSEH_OLD | WSEH_CONTEXT;
 232                 else if (parse_one_token(&arg, "new"))
 233                         val |= WSEH_NEW;
 234                 else if (parse_one_token(&arg, "old"))
 235                         val |= WSEH_OLD;
 236                 else if (parse_one_token(&arg, "context"))
 237                         val |= WSEH_CONTEXT;
 238                 else {
 239                         return -1 - (int)(arg - orig_arg);
 240                 }
 241                 if (*arg)
 242                         arg++;
 243         }
 244         return val;
 245 }
 246
 247 /*
 248  * These are to give UI layer defaults.
 249  * The core-level commands such as git-diff-files should
 250  * never be affected by the setting of diff.renames
 251  * the user happens to have in the configuration file.
 252  */
 253 void init_diff_ui_defaults(void)
 254 {
 255         diff_detect_rename_default = DIFF_DETECT_RENAME;
 256 }
 257
 258 int git_diff_heuristic_config(const char *var, const char *value, void *cb)
 259 {
 260         if (!strcmp(var, "diff.indentheuristic"))
 261                 diff_indent_heuristic = git_config_bool(var, value);
 262         return 0;
 263 }
 264
 265 static int parse_color_moved(const char *arg)
 266 {
 267         switch (git_parse_maybe_bool(arg)) {
 268         case 0:
 269                 return COLOR_MOVED_NO;
 270         case 1:
 271                 return COLOR_MOVED_DEFAULT;
 272         default:
 273                 break;
 274         }
 275
 276         if (!strcmp(arg, "no"))
 277                 return COLOR_MOVED_NO;
 278         else if (!strcmp(arg, "plain"))
 279                 return COLOR_MOVED_PLAIN;
 280         else if (!strcmp(arg, "blocks"))
 281                 return COLOR_MOVED_BLOCKS;
 282         else if (!strcmp(arg, "zebra"))
 283                 return COLOR_MOVED_ZEBRA;
 284         else if (!strcmp(arg, "default"))
 285                 return COLOR_MOVED_DEFAULT;
 286         else if (!strcmp(arg, "dimmed-zebra"))
 287                 return COLOR_MOVED_ZEBRA_DIM;
 288         else if (!strcmp(arg, "dimmed_zebra"))
 289                 return COLOR_MOVED_ZEBRA_DIM;
 290         else
 291                 return error(_("color moved setting must be one of 'no', 'default', 'blocks', 'zebra', 'dimmed-zebra', 'plain'"));
 292 }
 293
 294 static int parse_color_moved_ws(const char *arg)
 295 {
 296         int ret = 0;
 297         struct string_list l = STRING_LIST_INIT_DUP;
 298         struct string_list_item *i;
 299
 300         string_list_split(&l, arg, ',', -1);
 301
 302         for_each_string_list_item(i, &l) {
 303                 struct strbuf sb = STRBUF_INIT;
 304                 strbuf_addstr(&sb, i->string);
 305                 strbuf_trim(&sb);
 306
 307                 if (!strcmp(sb.buf, "no"))
 308                         ret = 0;
 309                 else if (!strcmp(sb.buf, "ignore-space-change"))
 310                         ret |= XDF_IGNORE_WHITESPACE_CHANGE;
 311                 else if (!strcmp(sb.buf, "ignore-space-at-eol"))
 312                         ret |= XDF_IGNORE_WHITESPACE_AT_EOL;
 313                 else if (!strcmp(sb.buf, "ignore-all-space"))
 314                         ret |= XDF_IGNORE_WHITESPACE;
 315                 else if (!strcmp(sb.buf, "allow-indentation-change"))
 316                         ret |= COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE;
 317                 else
 318                         error(_("ignoring unknown color-moved-ws mode '%s'"), sb.buf);
 319
 320                 strbuf_release(&sb);
 321         }
 322
 323         if ((ret & COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE) &&
 324             (ret & XDF_WHITESPACE_FLAGS))
 325                 die(_("color-moved-ws: allow-indentation-change cannot be combined with other whitespace modes"));
 326
 327         string_list_clear(&l, 0);
 328
 329         return ret;
 330 }
 331
 332 int git_diff_ui_config(const char *var, const char *value, void *cb)
 333 {
 334         if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 335                 diff_use_color_default = git_config_colorbool(var, value);
 336                 return 0;
 337         }
 338         if (!strcmp(var, "diff.colormoved")) {
 339                 int cm = parse_color_moved(value);
 340                 if (cm < 0)
 341                         return -1;
 342                 diff_color_moved_default = cm;
 343                 return 0;
 344         }
 345         if (!strcmp(var, "diff.colormovedws")) {
 346                 int cm = parse_color_moved_ws(value);
 347                 if (cm < 0)
 348                         return -1;
 349                 diff_color_moved_ws_default = cm;
 350                 return 0;
 351         }
 352         if (!strcmp(var, "diff.context")) {
 353                 diff_context_default = git_config_int(var, value);
 354                 if (diff_context_default < 0)
 355                         return -1;
 356                 return 0;
 357         }
 358         if (!strcmp(var, "diff.interhunkcontext")) {
 359                 diff_interhunk_context_default = git_config_int(var, value);
 360                 if (diff_interhunk_context_default < 0)
 361                         return -1;
 362                 return 0;
 363         }
 364         if (!strcmp(var, "diff.renames")) {
 365                 diff_detect_rename_default = git_config_rename(var, value);
 366                 return 0;
 367         }
 368         if (!strcmp(var, "diff.autorefreshindex")) {
 369                 diff_auto_refresh_index = git_config_bool(var, value);
 370                 return 0;
 371         }
 372         if (!strcmp(var, "diff.mnemonicprefix")) {
 373                 diff_mnemonic_prefix = git_config_bool(var, value);
 374                 return 0;
 375         }
 376         if (!strcmp(var, "diff.noprefix")) {
 377                 diff_no_prefix = git_config_bool(var, value);
 378                 return 0;
 379         }
 380         if (!strcmp(var, "diff.statgraphwidth")) {
 381                 diff_stat_graph_width = git_config_int(var, value);
 382                 return 0;
 383         }
 384         if (!strcmp(var, "diff.external"))
 385                 return git_config_string(&external_diff_cmd_cfg, var, value);
 386         if (!strcmp(var, "diff.wordregex"))
 387                 return git_config_string(&diff_word_regex_cfg, var, value);
 388         if (!strcmp(var, "diff.orderfile"))
 389                 return git_config_pathname(&diff_order_file_cfg, var, value);
 390
 391         if (!strcmp(var, "diff.ignoresubmodules"))
 392                 handle_ignore_submodules_arg(&default_diff_options, value);
 393
 394         if (!strcmp(var, "diff.submodule")) {
 395                 if (parse_submodule_params(&default_diff_options, value))
 396                         warning(_("Unknown value for 'diff.submodule' config variable: '%s'"),
 397                                 value);
 398                 return 0;
 399         }
 400
 401         if (!strcmp(var, "diff.algorithm")) {
 402                 diff_algorithm = parse_algorithm_value(value);
 403                 if (diff_algorithm < 0)
 404                         return -1;
 405                 return 0;
 406         }
 407
 408         if (!strcmp(var, "diff.wserrorhighlight")) {
 409                 int val = parse_ws_error_highlight(value);
 410                 if (val < 0)
 411                         return -1;
 412                 ws_error_highlight_default = val;
 413                 return 0;
 414         }
 415
 416         if (git_color_config(var, value, cb) < 0)
 417                 return -1;
 418
 419         return git_diff_basic_config(var, value, cb);
 420 }
 421
 422 int git_diff_basic_config(const char *var, const char *value, void *cb)
 423 {
 424         const char *name;
 425
 426         if (!strcmp(var, "diff.renamelimit")) {
 427                 diff_rename_limit_default = git_config_int(var, value);
 428                 return 0;
 429         }
 430
 431         if (userdiff_config(var, value) < 0)
 432                 return -1;
 433
 434         if (skip_prefix(var, "diff.color.", &name) ||
 435             skip_prefix(var, "color.diff.", &name)) {
 436                 int slot = parse_diff_color_slot(name);
 437                 if (slot < 0)
 438                         return 0;
 439                 if (!value)
 440                         return config_error_nonbool(var);
 441                 return color_parse(value, diff_colors[slot]);
 442         }
 443
 444         /* like GNU diff's --suppress-blank-empty option  */
 445         if (!strcmp(var, "diff.suppressblankempty") ||
 446                         /* for backwards compatibility */
 447                         !strcmp(var, "diff.suppress-blank-empty")) {
 448                 diff_suppress_blank_empty = git_config_bool(var, value);
 449                 return 0;
 450         }
 451
 452         if (!strcmp(var, "diff.dirstat")) {
 453                 struct strbuf errmsg = STRBUF_INIT;
 454                 default_diff_options.dirstat_permille = diff_dirstat_permille_default;
 455                 if (parse_dirstat_params(&default_diff_options, value, &errmsg))
 456                         warning(_("Found errors in 'diff.dirstat' config variable:\n%s"),
 457                                 errmsg.buf);
 458                 strbuf_release(&errmsg);
 459                 diff_dirstat_permille_default = default_diff_options.dirstat_permille;
 460                 return 0;
 461         }
 462
 463         if (git_diff_heuristic_config(var, value, cb) < 0)
 464                 return -1;
 465
 466         return git_default_config(var, value, cb);
 467 }
 468
 469 static char *quote_two(const char *one, const char *two)
 470 {
 471         int need_one = quote_c_style(one, NULL, NULL, 1);
 472         int need_two = quote_c_style(two, NULL, NULL, 1);
 473         struct strbuf res = STRBUF_INIT;
 474
 475         if (need_one + need_two) {
 476                 strbuf_addch(&res, '"');
 477                 quote_c_style(one, &res, NULL, 1);
 478                 quote_c_style(two, &res, NULL, 1);
 479                 strbuf_addch(&res, '"');
 480         } else {
 481                 strbuf_addstr(&res, one);
 482                 strbuf_addstr(&res, two);
 483         }
 484         return strbuf_detach(&res, NULL);
 485 }
 486
 487 static const char *external_diff(void)
 488 {
 489         static const char *external_diff_cmd = NULL;
 490         static int done_preparing = 0;
 491
 492         if (done_preparing)
 493                 return external_diff_cmd;
 494         external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 495         if (!external_diff_cmd)
 496                 external_diff_cmd = external_diff_cmd_cfg;
 497         done_preparing = 1;
 498         return external_diff_cmd;
 499 }
 500
 501 /*
 502  * Keep track of files used for diffing. Sometimes such an entry
 503  * refers to a temporary file, sometimes to an existing file, and
 504  * sometimes to "/dev/null".
 505  */
 506 static struct diff_tempfile {
 507         /*
 508          * filename external diff should read from, or NULL if this
 509          * entry is currently not in use:
 510          */
 511         const char *name;
 512
 513         char hex[GIT_MAX_HEXSZ + 1];
 514         char mode[10];
 515
 516         /*
 517          * If this diff_tempfile instance refers to a temporary file,
 518          * this tempfile object is used to manage its lifetime.
 519          */
 520         struct tempfile *tempfile;
 521 } diff_temp[2];
 522
 523 struct emit_callback {
 524         int color_diff;
 525         unsigned ws_rule;
 526         int blank_at_eof_in_preimage;
 527         int blank_at_eof_in_postimage;
 528         int lno_in_preimage;
 529         int lno_in_postimage;
 530         const char **label_path;
 531         struct diff_words_data *diff_words;
 532         struct diff_options *opt;
 533         struct strbuf *header;
 534 };
 535
 536 static int count_lines(const char *data, int size)
 537 {
 538         int count, ch, completely_empty = 1, nl_just_seen = 0;
 539         count = 0;
 540         while (0 < size--) {
 541                 ch = *data++;
 542                 if (ch == '\n') {
 543                         count++;
 544                         nl_just_seen = 1;
 545                         completely_empty = 0;
 546                 }
 547                 else {
 548                         nl_just_seen = 0;
 549                         completely_empty = 0;
 550                 }
 551         }
 552         if (completely_empty)
 553                 return 0;
 554         if (!nl_just_seen)
 555                 count++; /* no trailing newline */
 556         return count;
 557 }
 558
 559 static int fill_mmfile(struct repository *r, mmfile_t *mf,
 560                        struct diff_filespec *one)
 561 {
 562         if (!DIFF_FILE_VALID(one)) {
 563                 mf->ptr = (char *)""; /* does not matter */
 564                 mf->size = 0;
 565                 return 0;
 566         }
 567         else if (diff_populate_filespec(r, one, 0))
 568                 return -1;
 569
 570         mf->ptr = one->data;
 571         mf->size = one->size;
 572         return 0;
 573 }
 574
 575 /* like fill_mmfile, but only for size, so we can avoid retrieving blob */
 576 static unsigned long diff_filespec_size(struct repository *r,
 577                                         struct diff_filespec *one)
 578 {
 579         if (!DIFF_FILE_VALID(one))
 580                 return 0;
 581         diff_populate_filespec(r, one, CHECK_SIZE_ONLY);
 582         return one->size;
 583 }
 584
 585 static int count_trailing_blank(mmfile_t *mf, unsigned ws_rule)
 586 {
 587         char *ptr = mf->ptr;
 588         long size = mf->size;
 589         int cnt = 0;
 590
 591         if (!size)
 592                 return cnt;
 593         ptr += size - 1; /* pointing at the very end */
 594         if (*ptr != '\n')
 595                 ; /* incomplete line */
 596         else
 597                 ptr--; /* skip the last LF */
 598         while (mf->ptr < ptr) {
 599                 char *prev_eol;
 600                 for (prev_eol = ptr; mf->ptr <= prev_eol; prev_eol--)
 601                         if (*prev_eol == '\n')
 602                                 break;
 603                 if (!ws_blank_line(prev_eol + 1, ptr - prev_eol, ws_rule))
 604                         break;
 605                 cnt++;
 606                 ptr = prev_eol - 1;
 607         }
 608         return cnt;
 609 }
 610
 611 static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
 612                                struct emit_callback *ecbdata)
 613 {
 614         int l1, l2, at;
 615         unsigned ws_rule = ecbdata->ws_rule;
 616         l1 = count_trailing_blank(mf1, ws_rule);
 617         l2 = count_trailing_blank(mf2, ws_rule);
 618         if (l2 <= l1) {
 619                 ecbdata->blank_at_eof_in_preimage = 0;
 620                 ecbdata->blank_at_eof_in_postimage = 0;
 621                 return;
 622         }
 623         at = count_lines(mf1->ptr, mf1->size);
 624         ecbdata->blank_at_eof_in_preimage = (at - l1) + 1;
 625
 626         at = count_lines(mf2->ptr, mf2->size);
 627         ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
 628 }
 629
 630 static void emit_line_0(struct diff_options *o,
 631                         const char *set_sign, const char *set, unsigned reverse, const char *reset,
 632                         int first, const char *line, int len)
 633 {
 634         int has_trailing_newline, has_trailing_carriage_return;
 635         int needs_reset = 0; /* at the end of the line */
 636         FILE *file = o->file;
 637
 638         fputs(diff_line_prefix(o), file);
 639
 640         has_trailing_newline = (len > 0 && line[len-1] == '\n');
 641         if (has_trailing_newline)
 642                 len--;
 643
 644         has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
 645         if (has_trailing_carriage_return)
 646                 len--;
 647
 648         if (!len && !first)
 649                 goto end_of_line;
 650
 651         if (reverse && want_color(o->use_color)) {
 652                 fputs(GIT_COLOR_REVERSE, file);
 653                 needs_reset = 1;
 654         }
 655
 656         if (set_sign) {
 657                 fputs(set_sign, file);
 658                 needs_reset = 1;
 659         }
 660
 661         if (first)
 662                 fputc(first, file);
 663
 664         if (!len)
 665                 goto end_of_line;
 666
 667         if (set) {
 668                 if (set_sign && set != set_sign)
 669                         fputs(reset, file);
 670                 fputs(set, file);
 671                 needs_reset = 1;
 672         }
 673         fwrite(line, len, 1, file);
 674         needs_reset = 1; /* 'line' may contain color codes. */
 675
 676 end_of_line:
 677         if (needs_reset)
 678                 fputs(reset, file);
 679         if (has_trailing_carriage_return)
 680                 fputc('\r', file);
 681         if (has_trailing_newline)
 682                 fputc('\n', file);
 683 }
 684
 685 static void emit_line(struct diff_options *o, const char *set, const char *reset,
 686                       const char *line, int len)
 687 {
 688         emit_line_0(o, set, NULL, 0, reset, 0, line, len);
 689 }
 690
 691 enum diff_symbol {
 692         DIFF_SYMBOL_BINARY_DIFF_HEADER,
 693         DIFF_SYMBOL_BINARY_DIFF_HEADER_DELTA,
 694         DIFF_SYMBOL_BINARY_DIFF_HEADER_LITERAL,
 695         DIFF_SYMBOL_BINARY_DIFF_BODY,
 696         DIFF_SYMBOL_BINARY_DIFF_FOOTER,
 697         DIFF_SYMBOL_STATS_SUMMARY_NO_FILES,
 698         DIFF_SYMBOL_STATS_SUMMARY_ABBREV,
 699         DIFF_SYMBOL_STATS_SUMMARY_INSERTS_DELETES,
 700         DIFF_SYMBOL_STATS_LINE,
 701         DIFF_SYMBOL_WORD_DIFF,
 702         DIFF_SYMBOL_STAT_SEP,
 703         DIFF_SYMBOL_SUMMARY,
 704         DIFF_SYMBOL_SUBMODULE_ADD,
 705         DIFF_SYMBOL_SUBMODULE_DEL,
 706         DIFF_SYMBOL_SUBMODULE_UNTRACKED,
 707         DIFF_SYMBOL_SUBMODULE_MODIFIED,
 708         DIFF_SYMBOL_SUBMODULE_HEADER,
 709         DIFF_SYMBOL_SUBMODULE_ERROR,
 710         DIFF_SYMBOL_SUBMODULE_PIPETHROUGH,
 711         DIFF_SYMBOL_REWRITE_DIFF,
 712         DIFF_SYMBOL_BINARY_FILES,
 713         DIFF_SYMBOL_HEADER,
 714         DIFF_SYMBOL_FILEPAIR_PLUS,
 715         DIFF_SYMBOL_FILEPAIR_MINUS,
 716         DIFF_SYMBOL_WORDS_PORCELAIN,
 717         DIFF_SYMBOL_WORDS,
 718         DIFF_SYMBOL_CONTEXT,
 719         DIFF_SYMBOL_CONTEXT_INCOMPLETE,
 720         DIFF_SYMBOL_PLUS,
 721         DIFF_SYMBOL_MINUS,
 722         DIFF_SYMBOL_NO_LF_EOF,
 723         DIFF_SYMBOL_CONTEXT_FRAGINFO,
 724         DIFF_SYMBOL_CONTEXT_MARKER,
 725         DIFF_SYMBOL_SEPARATOR
 726 };
 727 /*
 728  * Flags for content lines:
 729  * 0..12 are whitespace rules
 730  * 13-15 are WSEH_NEW | WSEH_OLD | WSEH_CONTEXT
 731  * 16 is marking if the line is blank at EOF
 732  */
 733 #define DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF      (1<<16)
 734 #define DIFF_SYMBOL_MOVED_LINE                  (1<<17)
 735 #define DIFF_SYMBOL_MOVED_LINE_ALT              (1<<18)
 736 #define DIFF_SYMBOL_MOVED_LINE_UNINTERESTING    (1<<19)
 737 #define DIFF_SYMBOL_CONTENT_WS_MASK (WSEH_NEW | WSEH_OLD | WSEH_CONTEXT | WS_RULE_MASK)
 738
 739 /*
 740  * This struct is used when we need to buffer the output of the diff output.
 741  *
 742  * NEEDSWORK: Instead of storing a copy of the line, add an offset pointer
 743  * into the pre/post image file. This pointer could be a union with the
 744  * line pointer. By storing an offset into the file instead of the literal line,
 745  * we can decrease the memory footprint for the buffered output. At first we
 746  * may want to only have indirection for the content lines, but we could also
 747  * enhance the state for emitting prefabricated lines, e.g. the similarity
 748  * score line or hunk/file headers would only need to store a number or path
 749  * and then the output can be constructed later on depending on state.
 750  */
 751 struct emitted_diff_symbol {
 752         const char *line;
 753         int len;
 754         int flags;
 755         enum diff_symbol s;
 756 };
 757 #define EMITTED_DIFF_SYMBOL_INIT {NULL}
 758
 759 struct emitted_diff_symbols {
 760         struct emitted_diff_symbol *buf;
 761         int nr, alloc;
 762 };
 763 #define EMITTED_DIFF_SYMBOLS_INIT {NULL, 0, 0}
 764
 765 static void append_emitted_diff_symbol(struct diff_options *o,
 766                                        struct emitted_diff_symbol *e)
 767 {
 768         struct emitted_diff_symbol *f;
 769
 770         ALLOC_GROW(o->emitted_symbols->buf,
 771                    o->emitted_symbols->nr + 1,
 772                    o->emitted_symbols->alloc);
 773         f = &o->emitted_symbols->buf[o->emitted_symbols->nr++];
 774
 775         memcpy(f, e, sizeof(struct emitted_diff_symbol));
 776         f->line = e->line ? xmemdupz(e->line, e->len) : NULL;
 777 }
 778
 779 struct moved_entry {
 780         struct hashmap_entry ent;
 781         const struct emitted_diff_symbol *es;
 782         struct moved_entry *next_line;
 783 };
 784
 785 /**
 786  * The struct ws_delta holds white space differences between moved lines, i.e.
 787  * between '+' and '-' lines that have been detected to be a move.
 788  * The string contains the difference in leading white spaces, before the
 789  * rest of the line is compared using the white space config for move
 790  * coloring. The current_longer indicates if the first string in the
 791  * comparision is longer than the second.
 792  */
 793 struct ws_delta {
 794         char *string;
 795         unsigned int current_longer : 1;
 796 };
 797 #define WS_DELTA_INIT { NULL, 0 }
 798
 799 struct moved_block {
 800         struct moved_entry *match;
 801         struct ws_delta wsd;
 802 };
 803
 804 static void moved_block_clear(struct moved_block *b)
 805 {
 806         FREE_AND_NULL(b->wsd.string);
 807         b->match = NULL;
 808 }
 809
 810 static int compute_ws_delta(const struct emitted_diff_symbol *a,
 811                              const struct emitted_diff_symbol *b,
 812                              struct ws_delta *out)
 813 {
 814         const struct emitted_diff_symbol *longer =  a->len > b->len ? a : b;
 815         const struct emitted_diff_symbol *shorter = a->len > b->len ? b : a;
 816         int d = longer->len - shorter->len;
 817
 818         if (strncmp(longer->line + d, shorter->line, shorter->len))
 819                 return 0;
 820
 821         out->string = xmemdupz(longer->line, d);
 822         out->current_longer = (a == longer);
 823
 824         return 1;
 825 }
 826
 827 static int cmp_in_block_with_wsd(const struct diff_options *o,
 828                                  const struct moved_entry *cur,
 829                                  const struct moved_entry *match,
 830                                  struct moved_block *pmb,
 831                                  int n)
 832 {
 833         struct emitted_diff_symbol *l = &o->emitted_symbols->buf[n];
 834         int al = cur->es->len, cl = l->len;
 835         const char *a = cur->es->line,
 836                    *b = match->es->line,
 837                    *c = l->line;
 838
 839         int wslen;
 840
 841         /*
 842          * We need to check if 'cur' is equal to 'match'.
 843          * As those are from the same (+/-) side, we do not need to adjust for
 844          * indent changes. However these were found using fuzzy matching
 845          * so we do have to check if they are equal.
 846          */
 847         if (strcmp(a, b))
 848                 return 1;
 849
 850         if (!pmb->wsd.string)
 851                 /*
 852                  * The white space delta is not active? This can happen
 853                  * when we exit early in this function.
 854                  */
 855                 return 1;
 856
 857         /*
 858          * The indent changes of the block are known and stored in
 859          * pmb->wsd; however we need to check if the indent changes of the
 860          * current line are still the same as before.
 861          *
 862          * To do so we need to compare 'l' to 'cur', adjusting the
 863          * one of them for the white spaces, depending which was longer.
 864          */
 865
 866         wslen = strlen(pmb->wsd.string);
 867         if (pmb->wsd.current_longer) {
 868                 c += wslen;
 869                 cl -= wslen;
 870         } else {
 871                 a += wslen;
 872                 al -= wslen;
 873         }
 874
 875         if (al != cl || memcmp(a, c, al))
 876                 return 1;
 877
 878         return 0;
 879 }
 880
 881 static int moved_entry_cmp(const void *hashmap_cmp_fn_data,
 882                            const void *entry,
 883                            const void *entry_or_key,
 884                            const void *keydata)
 885 {
 886         const struct diff_options *diffopt = hashmap_cmp_fn_data;
 887         const struct moved_entry *a = entry;
 888         const struct moved_entry *b = entry_or_key;
 889         unsigned flags = diffopt->color_moved_ws_handling
 890                          & XDF_WHITESPACE_FLAGS;
 891
 892         if (diffopt->color_moved_ws_handling &
 893             COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE)
 894                 /*
 895                  * As there is not specific white space config given,
 896                  * we'd need to check for a new block, so ignore all
 897                  * white space. The setup of the white space
 898                  * configuration for the next block is done else where
 899                  */
 900                 flags |= XDF_IGNORE_WHITESPACE;
 901
 902         return !xdiff_compare_lines(a->es->line, a->es->len,
 903                                     b->es->line, b->es->len,
 904                                     flags);
 905 }
 906
 907 static struct moved_entry *prepare_entry(struct diff_options *o,
 908                                          int line_no)
 909 {
 910         struct moved_entry *ret = xmalloc(sizeof(*ret));
 911         struct emitted_diff_symbol *l = &o->emitted_symbols->buf[line_no];
 912         unsigned flags = o->color_moved_ws_handling & XDF_WHITESPACE_FLAGS;
 913
 914         ret->ent.hash = xdiff_hash_string(l->line, l->len, flags);
 915         ret->es = l;
 916         ret->next_line = NULL;
 917
 918         return ret;
 919 }
 920
 921 static void add_lines_to_move_detection(struct diff_options *o,
 922                                         struct hashmap *add_lines,
 923                                         struct hashmap *del_lines)
 924 {
 925         struct moved_entry *prev_line = NULL;
 926
 927         int n;
 928         for (n = 0; n < o->emitted_symbols->nr; n++) {
 929                 struct hashmap *hm;
 930                 struct moved_entry *key;
 931
 932                 switch (o->emitted_symbols->buf[n].s) {
 933                 case DIFF_SYMBOL_PLUS:
 934                         hm = add_lines;
 935                         break;
 936                 case DIFF_SYMBOL_MINUS:
 937                         hm = del_lines;
 938                         break;
 939                 default:
 940                         prev_line = NULL;
 941                         continue;
 942                 }
 943
 944                 key = prepare_entry(o, n);
 945                 if (prev_line && prev_line->es->s == o->emitted_symbols->buf[n].s)
 946                         prev_line->next_line = key;
 947
 948                 hashmap_add(hm, key);
 949                 prev_line = key;
 950         }
 951 }
 952
 953 static void pmb_advance_or_null(struct diff_options *o,
 954                                 struct moved_entry *match,
 955                                 struct hashmap *hm,
 956                                 struct moved_block *pmb,
 957                                 int pmb_nr)
 958 {
 959         int i;
 960         for (i = 0; i < pmb_nr; i++) {
 961                 struct moved_entry *prev = pmb[i].match;
 962                 struct moved_entry *cur = (prev && prev->next_line) ?
 963                                 prev->next_line : NULL;
 964                 if (cur && !hm->cmpfn(o, cur, match, NULL)) {
 965                         pmb[i].match = cur;
 966                 } else {
 967                         pmb[i].match = NULL;
 968                 }
 969         }
 970 }
 971
 972 static void pmb_advance_or_null_multi_match(struct diff_options *o,
 973                                             struct moved_entry *match,
 974                                             struct hashmap *hm,
 975                                             struct moved_block *pmb,
 976                                             int pmb_nr, int n)
 977 {
 978         int i;
 979         char *got_match = xcalloc(1, pmb_nr);
 980
 981         for (; match; match = hashmap_get_next(hm, match)) {
 982                 for (i = 0; i < pmb_nr; i++) {
 983                         struct moved_entry *prev = pmb[i].match;
 984                         struct moved_entry *cur = (prev && prev->next_line) ?
 985                                         prev->next_line : NULL;
 986                         if (!cur)
 987                                 continue;
 988                         if (!cmp_in_block_with_wsd(o, cur, match, &pmb[i], n))
 989                                 got_match[i] |= 1;
 990                 }
 991         }
 992
 993         for (i = 0; i < pmb_nr; i++) {
 994                 if (got_match[i]) {
 995                         /* Advance to the next line */
 996                         pmb[i].match = pmb[i].match->next_line;
 997                 } else {
 998                         moved_block_clear(&pmb[i]);
 999                 }
1000         }
1001
1002         free(got_match);
1003 }
1004
1005 static int shrink_potential_moved_blocks(struct moved_block *pmb,
1006                                          int pmb_nr)
1007 {
1008         int lp, rp;
1009
1010         /* Shrink the set of potential block to the remaining running */
1011         for (lp = 0, rp = pmb_nr - 1; lp <= rp;) {
1012                 while (lp < pmb_nr && pmb[lp].match)
1013                         lp++;
1014                 /* lp points at the first NULL now */
1015
1016                 while (rp > -1 && !pmb[rp].match)
1017                         rp--;
1018                 /* rp points at the last non-NULL */
1019
1020                 if (lp < pmb_nr && rp > -1 && lp < rp) {
1021                         pmb[lp] = pmb[rp];
1022                         pmb[rp].match = NULL;
1023                         pmb[rp].wsd.string = NULL;
1024                         rp--;
1025                         lp++;
1026                 }
1027         }
1028
1029         /* Remember the number of running sets */
1030         return rp + 1;
1031 }
1032
1033 /*
1034  * If o->color_moved is COLOR_MOVED_PLAIN, this function does nothing.
1035  *
1036  * Otherwise, if the last block has fewer alphanumeric characters than
1037  * COLOR_MOVED_MIN_ALNUM_COUNT, unset DIFF_SYMBOL_MOVED_LINE on all lines in
1038  * that block.
1039  *
1040  * The last block consists of the (n - block_length)'th line up to but not
1041  * including the nth line.
1042  *
1043  * NEEDSWORK: This uses the same heuristic as blame_entry_score() in blame.c.
1044  * Think of a way to unify them.
1045  */
1046 static void adjust_last_block(struct diff_options *o, int n, int block_length)
1047 {
1048         int i, alnum_count = 0;
1049         if (o->color_moved == COLOR_MOVED_PLAIN)
1050                 return;
1051         for (i = 1; i < block_length + 1; i++) {
1052                 const char *c = o->emitted_symbols->buf[n - i].line;
1053                 for (; *c; c++) {
1054                         if (!isalnum(*c))
1055                                 continue;
1056                         alnum_count++;
1057                         if (alnum_count >= COLOR_MOVED_MIN_ALNUM_COUNT)
1058                                 return;
1059                 }
1060         }
1061         for (i = 1; i < block_length + 1; i++)
1062                 o->emitted_symbols->buf[n - i].flags &= ~DIFF_SYMBOL_MOVED_LINE;
1063 }
1064
1065 /* Find blocks of moved code, delegate actual coloring decision to helper */
1066 static void mark_color_as_moved(struct diff_options *o,
1067                                 struct hashmap *add_lines,
1068                                 struct hashmap *del_lines)
1069 {
1070         struct moved_block *pmb = NULL; /* potentially moved blocks */
1071         int pmb_nr = 0, pmb_alloc = 0;
1072         int n, flipped_block = 1, block_length = 0;
1073
1074
1075         for (n = 0; n < o->emitted_symbols->nr; n++) {
1076                 struct hashmap *hm = NULL;
1077                 struct moved_entry *key;
1078                 struct moved_entry *match = NULL;
1079                 struct emitted_diff_symbol *l = &o->emitted_symbols->buf[n];
1080
1081                 switch (l->s) {
1082                 case DIFF_SYMBOL_PLUS:
1083                         hm = del_lines;
1084                         key = prepare_entry(o, n);
1085                         match = hashmap_get(hm, key, NULL);
1086                         free(key);
1087                         break;
1088                 case DIFF_SYMBOL_MINUS:
1089                         hm = add_lines;
1090                         key = prepare_entry(o, n);
1091                         match = hashmap_get(hm, key, NULL);
1092                         free(key);
1093                         break;
1094                 default:
1095                         flipped_block = 1;
1096                 }
1097
1098                 if (!match) {
1099                         int i;
1100
1101                         adjust_last_block(o, n, block_length);
1102                         for(i = 0; i < pmb_nr; i++)
1103                                 moved_block_clear(&pmb[i]);
1104                         pmb_nr = 0;
1105                         block_length = 0;
1106                         continue;
1107                 }
1108
1109                 if (o->color_moved == COLOR_MOVED_PLAIN) {
1110                         l->flags |= DIFF_SYMBOL_MOVED_LINE;
1111                         continue;
1112                 }
1113
1114                 if (o->color_moved_ws_handling &
1115                     COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE)
1116                         pmb_advance_or_null_multi_match(o, match, hm, pmb, pmb_nr, n);
1117                 else
1118                         pmb_advance_or_null(o, match, hm, pmb, pmb_nr);
1119
1120                 pmb_nr = shrink_potential_moved_blocks(pmb, pmb_nr);
1121
1122                 if (pmb_nr == 0) {
1123                         /*
1124                          * The current line is the start of a new block.
1125                          * Setup the set of potential blocks.
1126                          */
1127                         for (; match; match = hashmap_get_next(hm, match)) {
1128                                 ALLOC_GROW(pmb, pmb_nr + 1, pmb_alloc);
1129                                 if (o->color_moved_ws_handling &
1130                                     COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE) {
1131                                         if (compute_ws_delta(l, match->es,
1132                                                              &pmb[pmb_nr].wsd))
1133                                                 pmb[pmb_nr++].match = match;
1134                                 } else {
1135                                         pmb[pmb_nr].wsd.string = NULL;
1136                                         pmb[pmb_nr++].match = match;
1137                                 }
1138                         }
1139
1140                         flipped_block = (flipped_block + 1) % 2;
1141
1142                         adjust_last_block(o, n, block_length);
1143                         block_length = 0;
1144                 }
1145
1146                 if (pmb_nr) {
1147                         block_length++;
1148
1149                         l->flags |= DIFF_SYMBOL_MOVED_LINE;
1150                         if (flipped_block && o->color_moved != COLOR_MOVED_BLOCKS)
1151                                 l->flags |= DIFF_SYMBOL_MOVED_LINE_ALT;
1152                 }
1153         }
1154         adjust_last_block(o, n, block_length);
1155
1156         for(n = 0; n < pmb_nr; n++)
1157                 moved_block_clear(&pmb[n]);
1158         free(pmb);
1159 }
1160
1161 #define DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK \
1162   (DIFF_SYMBOL_MOVED_LINE | DIFF_SYMBOL_MOVED_LINE_ALT)
1163 static void dim_moved_lines(struct diff_options *o)
1164 {
1165         int n;
1166         for (n = 0; n < o->emitted_symbols->nr; n++) {
1167                 struct emitted_diff_symbol *prev = (n != 0) ?
1168                                 &o->emitted_symbols->buf[n - 1] : NULL;
1169                 struct emitted_diff_symbol *l = &o->emitted_symbols->buf[n];
1170                 struct emitted_diff_symbol *next =
1171                                 (n < o->emitted_symbols->nr - 1) ?
1172                                 &o->emitted_symbols->buf[n + 1] : NULL;
1173
1174                 /* Not a plus or minus line? */
1175                 if (l->s != DIFF_SYMBOL_PLUS && l->s != DIFF_SYMBOL_MINUS)
1176                         continue;
1177
1178                 /* Not a moved line? */
1179                 if (!(l->flags & DIFF_SYMBOL_MOVED_LINE))
1180                         continue;
1181
1182                 /*
1183                  * If prev or next are not a plus or minus line,
1184                  * pretend they don't exist
1185                  */
1186                 if (prev && prev->s != DIFF_SYMBOL_PLUS &&
1187                             prev->s != DIFF_SYMBOL_MINUS)
1188                         prev = NULL;
1189                 if (next && next->s != DIFF_SYMBOL_PLUS &&
1190                             next->s != DIFF_SYMBOL_MINUS)
1191                         next = NULL;
1192
1193                 /* Inside a block? */
1194                 if ((prev &&
1195                     (prev->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK) ==
1196                     (l->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK)) &&
1197                     (next &&
1198                     (next->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK) ==
1199                     (l->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK))) {
1200                         l->flags |= DIFF_SYMBOL_MOVED_LINE_UNINTERESTING;
1201                         continue;
1202                 }
1203
1204                 /* Check if we are at an interesting bound: */
1205                 if (prev && (prev->flags & DIFF_SYMBOL_MOVED_LINE) &&
1206                     (prev->flags & DIFF_SYMBOL_MOVED_LINE_ALT) !=
1207                        (l->flags & DIFF_SYMBOL_MOVED_LINE_ALT))
1208                         continue;
1209                 if (next && (next->flags & DIFF_SYMBOL_MOVED_LINE) &&
1210                     (next->flags & DIFF_SYMBOL_MOVED_LINE_ALT) !=
1211                        (l->flags & DIFF_SYMBOL_MOVED_LINE_ALT))
1212                         continue;
1213
1214                 /*
1215                  * The boundary to prev and next are not interesting,
1216                  * so this line is not interesting as a whole
1217                  */
1218                 l->flags |= DIFF_SYMBOL_MOVED_LINE_UNINTERESTING;
1219         }
1220 }
1221
1222 static void emit_line_ws_markup(struct diff_options *o,
1223                                 const char *set_sign, const char *set,
1224                                 const char *reset,
1225                                 int sign_index, const char *line, int len,
1226                                 unsigned ws_rule, int blank_at_eof)
1227 {
1228         const char *ws = NULL;
1229         int sign = o->output_indicators[sign_index];
1230
1231         if (o->ws_error_highlight & ws_rule) {
1232                 ws = diff_get_color_opt(o, DIFF_WHITESPACE);
1233                 if (!*ws)
1234                         ws = NULL;
1235         }
1236
1237         if (!ws && !set_sign)
1238                 emit_line_0(o, set, NULL, 0, reset, sign, line, len);
1239         else if (!ws) {
1240                 emit_line_0(o, set_sign, set, !!set_sign, reset, sign, line, len);
1241         } else if (blank_at_eof)
1242                 /* Blank line at EOF - paint '+' as well */
1243                 emit_line_0(o, ws, NULL, 0, reset, sign, line, len);
1244         else {
1245                 /* Emit just the prefix, then the rest. */
1246                 emit_line_0(o, set_sign ? set_sign : set, NULL, !!set_sign, reset,
1247                             sign, "", 0);
1248                 ws_check_emit(line, len, ws_rule,
1249                               o->file, set, reset, ws);
1250         }
1251 }
1252
1253 static void emit_diff_symbol_from_struct(struct diff_options *o,
1254                                          struct emitted_diff_symbol *eds)
1255 {
1256         static const char *nneof = " No newline at end of file\n";
1257         const char *context, *reset, *set, *set_sign, *meta, *fraginfo;
1258         struct strbuf sb = STRBUF_INIT;
1259
1260         enum diff_symbol s = eds->s;
1261         const char *line = eds->line;
1262         int len = eds->len;
1263         unsigned flags = eds->flags;
1264
1265         switch (s) {
1266         case DIFF_SYMBOL_NO_LF_EOF:
1267                 context = diff_get_color_opt(o, DIFF_CONTEXT);
1268                 reset = diff_get_color_opt(o, DIFF_RESET);
1269                 putc('\n', o->file);
1270                 emit_line_0(o, context, NULL, 0, reset, '\\',
1271                             nneof, strlen(nneof));
1272                 break;
1273         case DIFF_SYMBOL_SUBMODULE_HEADER:
1274         case DIFF_SYMBOL_SUBMODULE_ERROR:
1275         case DIFF_SYMBOL_SUBMODULE_PIPETHROUGH:
1276         case DIFF_SYMBOL_STATS_SUMMARY_INSERTS_DELETES:
1277         case DIFF_SYMBOL_SUMMARY:
1278         case DIFF_SYMBOL_STATS_LINE:
1279         case DIFF_SYMBOL_BINARY_DIFF_BODY:
1280         case DIFF_SYMBOL_CONTEXT_FRAGINFO:
1281                 emit_line(o, "", "", line, len);
1282                 break;
1283         case DIFF_SYMBOL_CONTEXT_INCOMPLETE:
1284         case DIFF_SYMBOL_CONTEXT_MARKER:
1285                 context = diff_get_color_opt(o, DIFF_CONTEXT);
1286                 reset = diff_get_color_opt(o, DIFF_RESET);
1287                 emit_line(o, context, reset, line, len);
1288                 break;
1289         case DIFF_SYMBOL_SEPARATOR:
1290                 fprintf(o->file, "%s%c",
1291                         diff_line_prefix(o),
1292                         o->line_termination);
1293                 break;
1294         case DIFF_SYMBOL_CONTEXT:
1295                 set = diff_get_color_opt(o, DIFF_CONTEXT);
1296                 reset = diff_get_color_opt(o, DIFF_RESET);
1297                 set_sign = NULL;
1298                 if (o->flags.dual_color_diffed_diffs) {
1299                         char c = !len ? 0 : line[0];
1300
1301                         if (c == '+')
1302                                 set = diff_get_color_opt(o, DIFF_FILE_NEW);
1303                         else if (c == '@')
1304                                 set = diff_get_color_opt(o, DIFF_FRAGINFO);
1305                         else if (c == '-')
1306                                 set = diff_get_color_opt(o, DIFF_FILE_OLD);
1307                 }
1308                 emit_line_ws_markup(o, set_sign, set, reset,
1309                                     OUTPUT_INDICATOR_CONTEXT, line, len,
1310                                     flags & (DIFF_SYMBOL_CONTENT_WS_MASK), 0);
1311                 break;
1312         case DIFF_SYMBOL_PLUS:
1313                 switch (flags & (DIFF_SYMBOL_MOVED_LINE |
1314                                  DIFF_SYMBOL_MOVED_LINE_ALT |
1315                                  DIFF_SYMBOL_MOVED_LINE_UNINTERESTING)) {
1316                 case DIFF_SYMBOL_MOVED_LINE |
1317                      DIFF_SYMBOL_MOVED_LINE_ALT |
1318                      DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1319                         set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED_ALT_DIM);
1320                         break;
1321                 case DIFF_SYMBOL_MOVED_LINE |
1322                      DIFF_SYMBOL_MOVED_LINE_ALT:
1323                         set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED_ALT);
1324                         break;
1325                 case DIFF_SYMBOL_MOVED_LINE |
1326                      DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1327                         set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED_DIM);
1328                         break;
1329                 case DIFF_SYMBOL_MOVED_LINE:
1330                         set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED);
1331                         break;
1332                 default:
1333                         set = diff_get_color_opt(o, DIFF_FILE_NEW);
1334                 }
1335                 reset = diff_get_color_opt(o, DIFF_RESET);
1336                 if (!o->flags.dual_color_diffed_diffs)
1337                         set_sign = NULL;
1338                 else {
1339                         char c = !len ? 0 : line[0];
1340
1341                         set_sign = set;
1342                         if (c == '-')
1343                                 set = diff_get_color_opt(o, DIFF_FILE_OLD_BOLD);
1344                         else if (c == '@')
1345                                 set = diff_get_color_opt(o, DIFF_FRAGINFO);
1346                         else if (c == '+')
1347                                 set = diff_get_color_opt(o, DIFF_FILE_NEW_BOLD);
1348                         else
1349                                 set = diff_get_color_opt(o, DIFF_CONTEXT_BOLD);
1350                         flags &= ~DIFF_SYMBOL_CONTENT_WS_MASK;
1351                 }
1352                 emit_line_ws_markup(o, set_sign, set, reset,
1353                                     OUTPUT_INDICATOR_NEW, line, len,
1354                                     flags & DIFF_SYMBOL_CONTENT_WS_MASK,
1355                                     flags & DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF);
1356                 break;
1357         case DIFF_SYMBOL_MINUS:
1358                 switch (flags & (DIFF_SYMBOL_MOVED_LINE |
1359                                  DIFF_SYMBOL_MOVED_LINE_ALT |
1360                                  DIFF_SYMBOL_MOVED_LINE_UNINTERESTING)) {
1361                 case DIFF_SYMBOL_MOVED_LINE |
1362                      DIFF_SYMBOL_MOVED_LINE_ALT |
1363                      DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1364                         set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED_ALT_DIM);
1365                         break;
1366                 case DIFF_SYMBOL_MOVED_LINE |
1367                      DIFF_SYMBOL_MOVED_LINE_ALT:
1368                         set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED_ALT);
1369                         break;
1370                 case DIFF_SYMBOL_MOVED_LINE |
1371                      DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1372                         set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED_DIM);
1373                         break;
1374                 case DIFF_SYMBOL_MOVED_LINE:
1375                         set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED);
1376                         break;
1377                 default:
1378                         set = diff_get_color_opt(o, DIFF_FILE_OLD);
1379                 }
1380                 reset = diff_get_color_opt(o, DIFF_RESET);
1381                 if (!o->flags.dual_color_diffed_diffs)
1382                         set_sign = NULL;
1383                 else {
1384                         char c = !len ? 0 : line[0];
1385
1386                         set_sign = set;
1387                         if (c == '+')
1388                                 set = diff_get_color_opt(o, DIFF_FILE_NEW_DIM);
1389                         else if (c == '@')
1390                                 set = diff_get_color_opt(o, DIFF_FRAGINFO);
1391                         else if (c == '-')
1392                                 set = diff_get_color_opt(o, DIFF_FILE_OLD_DIM);
1393                         else
1394                                 set = diff_get_color_opt(o, DIFF_CONTEXT_DIM);
1395                 }
1396                 emit_line_ws_markup(o, set_sign, set, reset,
1397                                     OUTPUT_INDICATOR_OLD, line, len,
1398                                     flags & DIFF_SYMBOL_CONTENT_WS_MASK, 0);
1399                 break;
1400         case DIFF_SYMBOL_WORDS_PORCELAIN:
1401                 context = diff_get_color_opt(o, DIFF_CONTEXT);
1402                 reset = diff_get_color_opt(o, DIFF_RESET);
1403                 emit_line(o, context, reset, line, len);
1404                 fputs("~\n", o->file);
1405                 break;
1406         case DIFF_SYMBOL_WORDS:
1407                 context = diff_get_color_opt(o, DIFF_CONTEXT);
1408                 reset = diff_get_color_opt(o, DIFF_RESET);
1409                 /*
1410                  * Skip the prefix character, if any.  With
1411                  * diff_suppress_blank_empty, there may be
1412                  * none.
1413                  */
1414                 if (line[0] != '\n') {
1415                         line++;
1416                         len--;
1417                 }
1418                 emit_line(o, context, reset, line, len);
1419                 break;
1420         case DIFF_SYMBOL_FILEPAIR_PLUS:
1421                 meta = diff_get_color_opt(o, DIFF_METAINFO);
1422                 reset = diff_get_color_opt(o, DIFF_RESET);
1423                 fprintf(o->file, "%s%s+++ %s%s%s\n", diff_line_prefix(o), meta,
1424                         line, reset,
1425                         strchr(line, ' ') ? "\t" : "");
1426                 break;
1427         case DIFF_SYMBOL_FILEPAIR_MINUS:
1428                 meta = diff_get_color_opt(o, DIFF_METAINFO);
1429                 reset = diff_get_color_opt(o, DIFF_RESET);
1430                 fprintf(o->file, "%s%s--- %s%s%s\n", diff_line_prefix(o), meta,
1431                         line, reset,
1432                         strchr(line, ' ') ? "\t" : "");
1433                 break;
1434         case DIFF_SYMBOL_BINARY_FILES:
1435         case DIFF_SYMBOL_HEADER:
1436                 fprintf(o->file, "%s", line);
1437                 break;
1438         case DIFF_SYMBOL_BINARY_DIFF_HEADER:
1439                 fprintf(o->file, "%sGIT binary patch\n", diff_line_prefix(o));
1440                 break;
1441         case DIFF_SYMBOL_BINARY_DIFF_HEADER_DELTA:
1442                 fprintf(o->file, "%sdelta %s\n", diff_line_prefix(o), line);
1443                 break;
1444         case DIFF_SYMBOL_BINARY_DIFF_HEADER_LITERAL:
1445                 fprintf(o->file, "%sliteral %s\n", diff_line_prefix(o), line);
1446                 break;
1447         case DIFF_SYMBOL_BINARY_DIFF_FOOTER:
1448                 fputs(diff_line_prefix(o), o->file);
1449                 fputc('\n', o->file);
1450                 break;
1451         case DIFF_SYMBOL_REWRITE_DIFF:
1452                 fraginfo = diff_get_color(o->use_color, DIFF_FRAGINFO);
1453                 reset = diff_get_color_opt(o, DIFF_RESET);
1454                 emit_line(o, fraginfo, reset, line, len);
1455                 break;
1456         case DIFF_SYMBOL_SUBMODULE_ADD:
1457                 set = diff_get_color_opt(o, DIFF_FILE_NEW);
1458                 reset = diff_get_color_opt(o, DIFF_RESET);
1459                 emit_line(o, set, reset, line, len);
1460                 break;
1461         case DIFF_SYMBOL_SUBMODULE_DEL:
1462                 set = diff_get_color_opt(o, DIFF_FILE_OLD);
1463                 reset = diff_get_color_opt(o, DIFF_RESET);
1464                 emit_line(o, set, reset, line, len);
1465                 break;
1466         case DIFF_SYMBOL_SUBMODULE_UNTRACKED:
1467                 fprintf(o->file, "%sSubmodule %s contains untracked content\n",
1468                         diff_line_prefix(o), line);
1469                 break;
1470         case DIFF_SYMBOL_SUBMODULE_MODIFIED:
1471                 fprintf(o->file, "%sSubmodule %s contains modified content\n",
1472                         diff_line_prefix(o), line);
1473                 break;
1474         case DIFF_SYMBOL_STATS_SUMMARY_NO_FILES:
1475                 emit_line(o, "", "", " 0 files changed\n",
1476                           strlen(" 0 files changed\n"));
1477                 break;
1478         case DIFF_SYMBOL_STATS_SUMMARY_ABBREV:
1479                 emit_line(o, "", "", " ...\n", strlen(" ...\n"));
1480                 break;
1481         case DIFF_SYMBOL_WORD_DIFF:
1482                 fprintf(o->file, "%.*s", len, line);
1483                 break;
1484         case DIFF_SYMBOL_STAT_SEP:
1485                 fputs(o->stat_sep, o->file);
1486                 break;
1487         default:
1488                 BUG("unknown diff symbol");
1489         }
1490         strbuf_release(&sb);
1491 }
1492
1493 static void emit_diff_symbol(struct diff_options *o, enum diff_symbol s,
1494                              const char *line, int len, unsigned flags)
1495 {
1496         struct emitted_diff_symbol e = {line, len, flags, s};
1497
1498         if (o->emitted_symbols)
1499                 append_emitted_diff_symbol(o, &e);
1500         else
1501                 emit_diff_symbol_from_struct(o, &e);
1502 }
1503
1504 void diff_emit_submodule_del(struct diff_options *o, const char *line)
1505 {
1506         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_DEL, line, strlen(line), 0);
1507 }
1508
1509 void diff_emit_submodule_add(struct diff_options *o, const char *line)
1510 {
1511         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_ADD, line, strlen(line), 0);
1512 }
1513
1514 void diff_emit_submodule_untracked(struct diff_options *o, const char *path)
1515 {
1516         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_UNTRACKED,
1517                          path, strlen(path), 0);
1518 }
1519
1520 void diff_emit_submodule_modified(struct diff_options *o, const char *path)
1521 {
1522         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_MODIFIED,
1523                          path, strlen(path), 0);
1524 }
1525
1526 void diff_emit_submodule_header(struct diff_options *o, const char *header)
1527 {
1528         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_HEADER,
1529                          header, strlen(header), 0);
1530 }
1531
1532 void diff_emit_submodule_error(struct diff_options *o, const char *err)
1533 {
1534         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_ERROR, err, strlen(err), 0);
1535 }
1536
1537 void diff_emit_submodule_pipethrough(struct diff_options *o,
1538                                      const char *line, int len)
1539 {
1540         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_PIPETHROUGH, line, len, 0);
1541 }
1542
1543 static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
1544 {
1545         if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
1546               ecbdata->blank_at_eof_in_preimage &&
1547               ecbdata->blank_at_eof_in_postimage &&
1548               ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
1549               ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
1550                 return 0;
1551         return ws_blank_line(line, len, ecbdata->ws_rule);
1552 }
1553
1554 static void emit_add_line(const char *reset,
1555                           struct emit_callback *ecbdata,
1556                           const char *line, int len)
1557 {
1558         unsigned flags = WSEH_NEW | ecbdata->ws_rule;
1559         if (new_blank_line_at_eof(ecbdata, line, len))
1560                 flags |= DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF;
1561
1562         emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_PLUS, line, len, flags);
1563 }
1564
1565 static void emit_del_line(const char *reset,
1566                           struct emit_callback *ecbdata,
1567                           const char *line, int len)
1568 {
1569         unsigned flags = WSEH_OLD | ecbdata->ws_rule;
1570         emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_MINUS, line, len, flags);
1571 }
1572
1573 static void emit_context_line(const char *reset,
1574                               struct emit_callback *ecbdata,
1575                               const char *line, int len)
1576 {
1577         unsigned flags = WSEH_CONTEXT | ecbdata->ws_rule;
1578         emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_CONTEXT, line, len, flags);
1579 }
1580
1581 static void emit_hunk_header(struct emit_callback *ecbdata,
1582                              const char *line, int len)
1583 {
1584         const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
1585         const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
1586         const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
1587         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1588         const char *reverse = ecbdata->color_diff ? GIT_COLOR_REVERSE : "";
1589         static const char atat[2] = { '@', '@' };
1590         const char *cp, *ep;
1591         struct strbuf msgbuf = STRBUF_INIT;
1592         int org_len = len;
1593         int i = 1;
1594
1595         /*
1596          * As a hunk header must begin with "@@ -<old>, +<new> @@",
1597          * it always is at least 10 bytes long.
1598          */
1599         if (len < 10 ||
1600             memcmp(line, atat, 2) ||
1601             !(ep = memmem(line + 2, len - 2, atat, 2))) {
1602                 emit_diff_symbol(ecbdata->opt,
1603                                  DIFF_SYMBOL_CONTEXT_MARKER, line, len, 0);
1604                 return;
1605         }
1606         ep += 2; /* skip over @@ */
1607
1608         /* The hunk header in fraginfo color */
1609         if (ecbdata->opt->flags.dual_color_diffed_diffs)
1610                 strbuf_addstr(&msgbuf, reverse);
1611         strbuf_addstr(&msgbuf, frag);
1612         strbuf_add(&msgbuf, line, ep - line);
1613         strbuf_addstr(&msgbuf, reset);
1614
1615         /*
1616          * trailing "\r\n"
1617          */
1618         for ( ; i < 3; i++)
1619                 if (line[len - i] == '\r' || line[len - i] == '\n')
1620                         len--;
1621
1622         /* blank before the func header */
1623         for (cp = ep; ep - line < len; ep++)
1624                 if (*ep != ' ' && *ep != '\t')
1625                         break;
1626         if (ep != cp) {
1627                 strbuf_addstr(&msgbuf, context);
1628                 strbuf_add(&msgbuf, cp, ep - cp);
1629                 strbuf_addstr(&msgbuf, reset);
1630         }
1631
1632         if (ep < line + len) {
1633                 strbuf_addstr(&msgbuf, func);
1634                 strbuf_add(&msgbuf, ep, line + len - ep);
1635                 strbuf_addstr(&msgbuf, reset);
1636         }
1637
1638         strbuf_add(&msgbuf, line + len, org_len - len);
1639         strbuf_complete_line(&msgbuf);
1640         emit_diff_symbol(ecbdata->opt,
1641                          DIFF_SYMBOL_CONTEXT_FRAGINFO, msgbuf.buf, msgbuf.len, 0);
1642         strbuf_release(&msgbuf);
1643 }
1644
1645 static struct diff_tempfile *claim_diff_tempfile(void) {
1646         int i;
1647         for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
1648                 if (!diff_temp[i].name)
1649                         return diff_temp + i;
1650         BUG("diff is failing to clean up its tempfiles");
1651 }
1652
1653 static void remove_tempfile(void)
1654 {
1655         int i;
1656         for (i = 0; i < ARRAY_SIZE(diff_temp); i++) {
1657                 if (is_tempfile_active(diff_temp[i].tempfile))
1658                         delete_tempfile(&diff_temp[i].tempfile);
1659                 diff_temp[i].name = NULL;
1660         }
1661 }
1662
1663 static void add_line_count(struct strbuf *out, int count)
1664 {
1665         switch (count) {
1666         case 0:
1667                 strbuf_addstr(out, "0,0");
1668                 break;
1669         case 1:
1670                 strbuf_addstr(out, "1");
1671                 break;
1672         default:
1673                 strbuf_addf(out, "1,%d", count);
1674                 break;
1675         }
1676 }
1677
1678 static void emit_rewrite_lines(struct emit_callback *ecb,
1679                                int prefix, const char *data, int size)
1680 {
1681         const char *endp = NULL;
1682         const char *reset = diff_get_color(ecb->color_diff, DIFF_RESET);
1683
1684         while (0 < size) {
1685                 int len;
1686
1687                 endp = memchr(data, '\n', size);
1688                 len = endp ? (endp - data + 1) : size;
1689                 if (prefix != '+') {
1690                         ecb->lno_in_preimage++;
1691                         emit_del_line(reset, ecb, data, len);
1692                 } else {
1693                         ecb->lno_in_postimage++;
1694                         emit_add_line(reset, ecb, data, len);
1695                 }
1696                 size -= len;
1697                 data += len;
1698         }
1699         if (!endp)
1700                 emit_diff_symbol(ecb->opt, DIFF_SYMBOL_NO_LF_EOF, NULL, 0, 0);
1701 }
1702
1703 static void emit_rewrite_diff(const char *name_a,
1704                               const char *name_b,
1705                               struct diff_filespec *one,
1706                               struct diff_filespec *two,
1707                               struct userdiff_driver *textconv_one,
1708                               struct userdiff_driver *textconv_two,
1709                               struct diff_options *o)
1710 {
1711         int lc_a, lc_b;
1712         static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
1713         const char *a_prefix, *b_prefix;
1714         char *data_one, *data_two;
1715         size_t size_one, size_two;
1716         struct emit_callback ecbdata;
1717         struct strbuf out = STRBUF_INIT;
1718
1719         if (diff_mnemonic_prefix && o->flags.reverse_diff) {
1720                 a_prefix = o->b_prefix;
1721                 b_prefix = o->a_prefix;
1722         } else {
1723                 a_prefix = o->a_prefix;
1724                 b_prefix = o->b_prefix;
1725         }
1726
1727         name_a += (*name_a == '/');
1728         name_b += (*name_b == '/');
1729
1730         strbuf_reset(&a_name);
1731         strbuf_reset(&b_name);
1732         quote_two_c_style(&a_name, a_prefix, name_a, 0);
1733         quote_two_c_style(&b_name, b_prefix, name_b, 0);
1734
1735         size_one = fill_textconv(o->repo, textconv_one, one, &data_one);
1736         size_two = fill_textconv(o->repo, textconv_two, two, &data_two);
1737
1738         memset(&ecbdata, 0, sizeof(ecbdata));
1739         ecbdata.color_diff = want_color(o->use_color);
1740         ecbdata.ws_rule = whitespace_rule(o->repo->index, name_b);
1741         ecbdata.opt = o;
1742         if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
1743                 mmfile_t mf1, mf2;
1744                 mf1.ptr = (char *)data_one;
1745                 mf2.ptr = (char *)data_two;
1746                 mf1.size = size_one;
1747                 mf2.size = size_two;
1748                 check_blank_at_eof(&mf1, &mf2, &ecbdata);
1749         }
1750         ecbdata.lno_in_preimage = 1;
1751         ecbdata.lno_in_postimage = 1;
1752
1753         lc_a = count_lines(data_one, size_one);
1754         lc_b = count_lines(data_two, size_two);
1755
1756         emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_MINUS,
1757                          a_name.buf, a_name.len, 0);
1758         emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_PLUS,
1759                          b_name.buf, b_name.len, 0);
1760
1761         strbuf_addstr(&out, "@@ -");
1762         if (!o->irreversible_delete)
1763                 add_line_count(&out, lc_a);
1764         else
1765                 strbuf_addstr(&out, "?,?");
1766         strbuf_addstr(&out, " +");
1767         add_line_count(&out, lc_b);
1768         strbuf_addstr(&out, " @@\n");
1769         emit_diff_symbol(o, DIFF_SYMBOL_REWRITE_DIFF, out.buf, out.len, 0);
1770         strbuf_release(&out);
1771
1772         if (lc_a && !o->irreversible_delete)
1773                 emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
1774         if (lc_b)
1775                 emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
1776         if (textconv_one)
1777                 free((char *)data_one);
1778         if (textconv_two)
1779                 free((char *)data_two);
1780 }
1781
1782 struct diff_words_buffer {
1783         mmfile_t text;
1784         unsigned long alloc;
1785         struct diff_words_orig {
1786                 const char *begin, *end;
1787         } *orig;
1788         int orig_nr, orig_alloc;
1789 };
1790
1791 static void diff_words_append(char *line, unsigned long len,
1792                 struct diff_words_buffer *buffer)
1793 {
1794         ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
1795         line++;
1796         len--;
1797         memcpy(buffer->text.ptr + buffer->text.size, line, len);
1798         buffer->text.size += len;
1799         buffer->text.ptr[buffer->text.size] = '\0';
1800 }
1801
1802 struct diff_words_style_elem {
1803         const char *prefix;
1804         const char *suffix;
1805         const char *color; /* NULL; filled in by the setup code if
1806                             * color is enabled */
1807 };
1808
1809 struct diff_words_style {
1810         enum diff_words_type type;
1811         struct diff_words_style_elem new_word, old_word, ctx;
1812         const char *newline;
1813 };
1814
1815 static struct diff_words_style diff_words_styles[] = {
1816         { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
1817         { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
1818         { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
1819 };
1820
1821 struct diff_words_data {
1822         struct diff_words_buffer minus, plus;
1823         const char *current_plus;
1824         int last_minus;
1825         struct diff_options *opt;
1826         regex_t *word_regex;
1827         enum diff_words_type type;
1828         struct diff_words_style *style;
1829 };
1830
1831 static int fn_out_diff_words_write_helper(struct diff_options *o,
1832                                           struct diff_words_style_elem *st_el,
1833                                           const char *newline,
1834                                           size_t count, const char *buf)
1835 {
1836         int print = 0;
1837         struct strbuf sb = STRBUF_INIT;
1838
1839         while (count) {
1840                 char *p = memchr(buf, '\n', count);
1841                 if (print)
1842                         strbuf_addstr(&sb, diff_line_prefix(o));
1843
1844                 if (p != buf) {
1845                         const char *reset = st_el->color && *st_el->color ?
1846                                             GIT_COLOR_RESET : NULL;
1847                         if (st_el->color && *st_el->color)
1848                                 strbuf_addstr(&sb, st_el->color);
1849                         strbuf_addstr(&sb, st_el->prefix);
1850                         strbuf_add(&sb, buf, p ? p - buf : count);
1851                         strbuf_addstr(&sb, st_el->suffix);
1852                         if (reset)
1853                                 strbuf_addstr(&sb, reset);
1854                 }
1855                 if (!p)
1856                         goto out;
1857
1858                 strbuf_addstr(&sb, newline);
1859                 count -= p + 1 - buf;
1860                 buf = p + 1;
1861                 print = 1;
1862                 if (count) {
1863                         emit_diff_symbol(o, DIFF_SYMBOL_WORD_DIFF,
1864                                          sb.buf, sb.len, 0);
1865                         strbuf_reset(&sb);
1866                 }
1867         }
1868
1869 out:
1870         if (sb.len)
1871                 emit_diff_symbol(o, DIFF_SYMBOL_WORD_DIFF,
1872                                  sb.buf, sb.len, 0);
1873         strbuf_release(&sb);
1874         return 0;
1875 }
1876
1877 /*
1878  * '--color-words' algorithm can be described as:
1879  *
1880  *   1. collect the minus/plus lines of a diff hunk, divided into
1881  *      minus-lines and plus-lines;
1882  *
1883  *   2. break both minus-lines and plus-lines into words and
1884  *      place them into two mmfile_t with one word for each line;
1885  *
1886  *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
1887  *
1888  * And for the common parts of the both file, we output the plus side text.
1889  * diff_words->current_plus is used to trace the current position of the plus file
1890  * which printed. diff_words->last_minus is used to trace the last minus word
1891  * printed.
1892  *
1893  * For '--graph' to work with '--color-words', we need to output the graph prefix
1894  * on each line of color words output. Generally, there are two conditions on
1895  * which we should output the prefix.
1896  *
1897  *   1. diff_words->last_minus == 0 &&
1898  *      diff_words->current_plus == diff_words->plus.text.ptr
1899  *
1900  *      that is: the plus text must start as a new line, and if there is no minus
1901  *      word printed, a graph prefix must be printed.
1902  *
1903  *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
1904  *      *(diff_words->current_plus - 1) == '\n'
1905  *
1906  *      that is: a graph prefix must be printed following a '\n'
1907  */
1908 static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
1909 {
1910         if ((diff_words->last_minus == 0 &&
1911                 diff_words->current_plus == diff_words->plus.text.ptr) ||
1912                 (diff_words->current_plus > diff_words->plus.text.ptr &&
1913                 *(diff_words->current_plus - 1) == '\n')) {
1914                 return 1;
1915         } else {
1916                 return 0;
1917         }
1918 }
1919
1920 static void fn_out_diff_words_aux(void *priv,
1921                                   long minus_first, long minus_len,
1922                                   long plus_first, long plus_len,
1923                                   const char *func, long funclen)
1924 {
1925         struct diff_words_data *diff_words = priv;
1926         struct diff_words_style *style = diff_words->style;
1927         const char *minus_begin, *minus_end, *plus_begin, *plus_end;
1928         struct diff_options *opt = diff_words->opt;
1929         const char *line_prefix;
1930
1931         assert(opt);
1932         line_prefix = diff_line_prefix(opt);
1933
1934         /* POSIX requires that first be decremented by one if len == 0... */
1935         if (minus_len) {
1936                 minus_begin = diff_words->minus.orig[minus_first].begin;
1937                 minus_end =
1938                         diff_words->minus.orig[minus_first + minus_len - 1].end;
1939         } else
1940                 minus_begin = minus_end =
1941                         diff_words->minus.orig[minus_first].end;
1942
1943         if (plus_len) {
1944                 plus_begin = diff_words->plus.orig[plus_first].begin;
1945                 plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
1946         } else
1947                 plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
1948
1949         if (color_words_output_graph_prefix(diff_words)) {
1950                 fputs(line_prefix, diff_words->opt->file);
1951         }
1952         if (diff_words->current_plus != plus_begin) {
1953                 fn_out_diff_words_write_helper(diff_words->opt,
1954                                 &style->ctx, style->newline,
1955                                 plus_begin - diff_words->current_plus,
1956                                 diff_words->current_plus);
1957         }
1958         if (minus_begin != minus_end) {
1959                 fn_out_diff_words_write_helper(diff_words->opt,
1960                                 &style->old_word, style->newline,
1961                                 minus_end - minus_begin, minus_begin);
1962         }
1963         if (plus_begin != plus_end) {
1964                 fn_out_diff_words_write_helper(diff_words->opt,
1965                                 &style->new_word, style->newline,
1966                                 plus_end - plus_begin, plus_begin);
1967         }
1968
1969         diff_words->current_plus = plus_end;
1970         diff_words->last_minus = minus_first;
1971 }
1972
1973 /* This function starts looking at *begin, and returns 0 iff a word was found. */
1974 static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
1975                 int *begin, int *end)
1976 {
1977         if (word_regex && *begin < buffer->size) {
1978                 regmatch_t match[1];
1979                 if (!regexec_buf(word_regex, buffer->ptr + *begin,
1980                                  buffer->size - *begin, 1, match, 0)) {
1981                         char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
1982                                         '\n', match[0].rm_eo - match[0].rm_so);
1983                         *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
1984                         *begin += match[0].rm_so;
1985                         return *begin >= *end;
1986                 }
1987                 return -1;
1988         }
1989
1990         /* find the next word */
1991         while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
1992                 (*begin)++;
1993         if (*begin >= buffer->size)
1994                 return -1;
1995
1996         /* find the end of the word */
1997         *end = *begin + 1;
1998         while (*end < buffer->size && !isspace(buffer->ptr[*end]))
1999                 (*end)++;
2000
2001         return 0;
2002 }
2003
2004 /*
2005  * This function splits the words in buffer->text, stores the list with
2006  * newline separator into out, and saves the offsets of the original words
2007  * in buffer->orig.
2008  */
2009 static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
2010                 regex_t *word_regex)
2011 {
2012         int i, j;
2013         long alloc = 0;
2014
2015         out->size = 0;
2016         out->ptr = NULL;
2017
2018         /* fake an empty "0th" word */
2019         ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
2020         buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
2021         buffer->orig_nr = 1;
2022
2023         for (i = 0; i < buffer->text.size; i++) {
2024                 if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
2025                         return;
2026
2027                 /* store original boundaries */
2028                 ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
2029                                 buffer->orig_alloc);
2030                 buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
2031                 buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
2032                 buffer->orig_nr++;
2033
2034                 /* store one word */
2035                 ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
2036                 memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
2037                 out->ptr[out->size + j - i] = '\n';
2038                 out->size += j - i + 1;
2039
2040                 i = j - 1;
2041         }
2042 }
2043
2044 /* this executes the word diff on the accumulated buffers */
2045 static void diff_words_show(struct diff_words_data *diff_words)
2046 {
2047         xpparam_t xpp;
2048         xdemitconf_t xecfg;
2049         mmfile_t minus, plus;
2050         struct diff_words_style *style = diff_words->style;
2051
2052         struct diff_options *opt = diff_words->opt;
2053         const char *line_prefix;
2054
2055         assert(opt);
2056         line_prefix = diff_line_prefix(opt);
2057
2058         /* special case: only removal */
2059         if (!diff_words->plus.text.size) {
2060                 emit_diff_symbol(diff_words->opt, DIFF_SYMBOL_WORD_DIFF,
2061                                  line_prefix, strlen(line_prefix), 0);
2062                 fn_out_diff_words_write_helper(diff_words->opt,
2063                         &style->old_word, style->newline,
2064                         diff_words->minus.text.size,
2065                         diff_words->minus.text.ptr);
2066                 diff_words->minus.text.size = 0;
2067                 return;
2068         }
2069
2070         diff_words->current_plus = diff_words->plus.text.ptr;
2071         diff_words->last_minus = 0;
2072
2073         memset(&xpp, 0, sizeof(xpp));
2074         memset(&xecfg, 0, sizeof(xecfg));
2075         diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
2076         diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
2077         xpp.flags = 0;
2078         /* as only the hunk header will be parsed, we need a 0-context */
2079         xecfg.ctxlen = 0;
2080         if (xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, NULL,
2081                           diff_words, &xpp, &xecfg))
2082                 die("unable to generate word diff");
2083         free(minus.ptr);
2084         free(plus.ptr);
2085         if (diff_words->current_plus != diff_words->plus.text.ptr +
2086                         diff_words->plus.text.size) {
2087                 if (color_words_output_graph_prefix(diff_words))
2088                         emit_diff_symbol(diff_words->opt, DIFF_SYMBOL_WORD_DIFF,
2089                                          line_prefix, strlen(line_prefix), 0);
2090                 fn_out_diff_words_write_helper(diff_words->opt,
2091                         &style->ctx, style->newline,
2092                         diff_words->plus.text.ptr + diff_words->plus.text.size
2093                         - diff_words->current_plus, diff_words->current_plus);
2094         }
2095         diff_words->minus.text.size = diff_words->plus.text.size = 0;
2096 }
2097
2098 /* In "color-words" mode, show word-diff of words accumulated in the buffer */
2099 static void diff_words_flush(struct emit_callback *ecbdata)
2100 {
2101         struct diff_options *wo = ecbdata->diff_words->opt;
2102
2103         if (ecbdata->diff_words->minus.text.size ||
2104             ecbdata->diff_words->plus.text.size)
2105                 diff_words_show(ecbdata->diff_words);
2106
2107         if (wo->emitted_symbols) {
2108                 struct diff_options *o = ecbdata->opt;
2109                 struct emitted_diff_symbols *wol = wo->emitted_symbols;
2110                 int i;
2111
2112                 /*
2113                  * NEEDSWORK:
2114                  * Instead of appending each, concat all words to a line?
2115                  */
2116                 for (i = 0; i < wol->nr; i++)
2117                         append_emitted_diff_symbol(o, &wol->buf[i]);
2118
2119                 for (i = 0; i < wol->nr; i++)
2120                         free((void *)wol->buf[i].line);
2121
2122                 wol->nr = 0;
2123         }
2124 }
2125
2126 static void diff_filespec_load_driver(struct diff_filespec *one,
2127                                       struct index_state *istate)
2128 {
2129         /* Use already-loaded driver */
2130         if (one->driver)
2131                 return;
2132
2133         if (S_ISREG(one->mode))
2134                 one->driver = userdiff_find_by_path(istate, one->path);
2135
2136         /* Fallback to default settings */
2137         if (!one->driver)
2138                 one->driver = userdiff_find_by_name("default");
2139 }
2140
2141 static const char *userdiff_word_regex(struct diff_filespec *one,
2142                                        struct index_state *istate)
2143 {
2144         diff_filespec_load_driver(one, istate);
2145         return one->driver->word_regex;
2146 }
2147
2148 static void init_diff_words_data(struct emit_callback *ecbdata,
2149                                  struct diff_options *orig_opts,
2150                                  struct diff_filespec *one,
2151                                  struct diff_filespec *two)
2152 {
2153         int i;
2154         struct diff_options *o = xmalloc(sizeof(struct diff_options));
2155         memcpy(o, orig_opts, sizeof(struct diff_options));
2156
2157         ecbdata->diff_words =
2158                 xcalloc(1, sizeof(struct diff_words_data));
2159         ecbdata->diff_words->type = o->word_diff;
2160         ecbdata->diff_words->opt = o;
2161
2162         if (orig_opts->emitted_symbols)
2163                 o->emitted_symbols =
2164                         xcalloc(1, sizeof(struct emitted_diff_symbols));
2165
2166         if (!o->word_regex)
2167                 o->word_regex = userdiff_word_regex(one, o->repo->index);
2168         if (!o->word_regex)
2169                 o->word_regex = userdiff_word_regex(two, o->repo->index);
2170         if (!o->word_regex)
2171                 o->word_regex = diff_word_regex_cfg;
2172         if (o->word_regex) {
2173                 ecbdata->diff_words->word_regex = (regex_t *)
2174                         xmalloc(sizeof(regex_t));
2175                 if (regcomp(ecbdata->diff_words->word_regex,
2176                             o->word_regex,
2177                             REG_EXTENDED | REG_NEWLINE))
2178                         die("invalid regular expression: %s",
2179                             o->word_regex);
2180         }
2181         for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
2182                 if (o->word_diff == diff_words_styles[i].type) {
2183                         ecbdata->diff_words->style =
2184                                 &diff_words_styles[i];
2185                         break;
2186                 }
2187         }
2188         if (want_color(o->use_color)) {
2189                 struct diff_words_style *st = ecbdata->diff_words->style;
2190                 st->old_word.color = diff_get_color_opt(o, DIFF_FILE_OLD);
2191                 st->new_word.color = diff_get_color_opt(o, DIFF_FILE_NEW);
2192                 st->ctx.color = diff_get_color_opt(o, DIFF_CONTEXT);
2193         }
2194 }
2195
2196 static void free_diff_words_data(struct emit_callback *ecbdata)
2197 {
2198         if (ecbdata->diff_words) {
2199                 diff_words_flush(ecbdata);
2200                 free (ecbdata->diff_words->opt->emitted_symbols);
2201                 free (ecbdata->diff_words->opt);
2202                 free (ecbdata->diff_words->minus.text.ptr);
2203                 free (ecbdata->diff_words->minus.orig);
2204                 free (ecbdata->diff_words->plus.text.ptr);
2205                 free (ecbdata->diff_words->plus.orig);
2206                 if (ecbdata->diff_words->word_regex) {
2207                         regfree(ecbdata->diff_words->word_regex);
2208                         free(ecbdata->diff_words->word_regex);
2209                 }
2210                 FREE_AND_NULL(ecbdata->diff_words);
2211         }
2212 }
2213
2214 const char *diff_get_color(int diff_use_color, enum color_diff ix)
2215 {
2216         if (want_color(diff_use_color))
2217                 return diff_colors[ix];
2218         return "";
2219 }
2220
2221 const char *diff_line_prefix(struct diff_options *opt)
2222 {
2223         struct strbuf *msgbuf;
2224         if (!opt->output_prefix)
2225                 return "";
2226
2227         msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
2228         return msgbuf->buf;
2229 }
2230
2231 static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
2232 {
2233         const char *cp;
2234         unsigned long allot;
2235         size_t l = len;
2236
2237         cp = line;
2238         allot = l;
2239         while (0 < l) {
2240                 (void) utf8_width(&cp, &l);
2241                 if (!cp)
2242                         break; /* truncated in the middle? */
2243         }
2244         return allot - l;
2245 }
2246
2247 static void find_lno(const char *line, struct emit_callback *ecbdata)
2248 {
2249         const char *p;
2250         ecbdata->lno_in_preimage = 0;
2251         ecbdata->lno_in_postimage = 0;
2252         p = strchr(line, '-');
2253         if (!p)
2254                 return; /* cannot happen */
2255         ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
2256         p = strchr(p, '+');
2257         if (!p)
2258                 return; /* cannot happen */
2259         ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
2260 }
2261
2262 static void fn_out_consume(void *priv, char *line, unsigned long len)
2263 {
2264         struct emit_callback *ecbdata = priv;
2265         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
2266         struct diff_options *o = ecbdata->opt;
2267
2268         o->found_changes = 1;
2269
2270         if (ecbdata->header) {
2271                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
2272                                  ecbdata->header->buf, ecbdata->header->len, 0);
2273                 strbuf_reset(ecbdata->header);
2274                 ecbdata->header = NULL;
2275         }
2276
2277         if (ecbdata->label_path[0]) {
2278                 emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_MINUS,
2279                                  ecbdata->label_path[0],
2280                                  strlen(ecbdata->label_path[0]), 0);
2281                 emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_PLUS,
2282                                  ecbdata->label_path[1],
2283                                  strlen(ecbdata->label_path[1]), 0);
2284                 ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
2285         }
2286
2287         if (diff_suppress_blank_empty
2288             && len == 2 && line[0] == ' ' && line[1] == '\n') {
2289                 line[0] = '\n';
2290                 len = 1;
2291         }
2292
2293         if (line[0] == '@') {
2294                 if (ecbdata->diff_words)
2295                         diff_words_flush(ecbdata);
2296                 len = sane_truncate_line(ecbdata, line, len);
2297                 find_lno(line, ecbdata);
2298                 emit_hunk_header(ecbdata, line, len);
2299                 return;
2300         }
2301
2302         if (ecbdata->diff_words) {
2303                 enum diff_symbol s =
2304                         ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN ?
2305                         DIFF_SYMBOL_WORDS_PORCELAIN : DIFF_SYMBOL_WORDS;
2306                 if (line[0] == '-') {
2307                         diff_words_append(line, len,
2308                                           &ecbdata->diff_words->minus);
2309                         return;
2310                 } else if (line[0] == '+') {
2311                         diff_words_append(line, len,
2312                                           &ecbdata->diff_words->plus);
2313                         return;
2314                 } else if (starts_with(line, "\\ ")) {
2315                         /*
2316                          * Eat the "no newline at eof" marker as if we
2317                          * saw a "+" or "-" line with nothing on it,
2318                          * and return without diff_words_flush() to
2319                          * defer processing. If this is the end of
2320                          * preimage, more "+" lines may come after it.
2321                          */
2322                         return;
2323                 }
2324                 diff_words_flush(ecbdata);
2325                 emit_diff_symbol(o, s, line, len, 0);
2326                 return;
2327         }
2328
2329         switch (line[0]) {
2330         case '+':
2331                 ecbdata->lno_in_postimage++;
2332                 emit_add_line(reset, ecbdata, line + 1, len - 1);
2333                 break;
2334         case '-':
2335                 ecbdata->lno_in_preimage++;
2336                 emit_del_line(reset, ecbdata, line + 1, len - 1);
2337                 break;
2338         case ' ':
2339                 ecbdata->lno_in_postimage++;
2340                 ecbdata->lno_in_preimage++;
2341                 emit_context_line(reset, ecbdata, line + 1, len - 1);
2342                 break;
2343         default:
2344                 /* incomplete line at the end */
2345                 ecbdata->lno_in_preimage++;
2346                 emit_diff_symbol(o, DIFF_SYMBOL_CONTEXT_INCOMPLETE,
2347                                  line, len, 0);
2348                 break;
2349         }
2350 }
2351
2352 static void pprint_rename(struct strbuf *name, const char *a, const char *b)
2353 {
2354         const char *old_name = a;
2355         const char *new_name = b;
2356         int pfx_length, sfx_length;
2357         int pfx_adjust_for_slash;
2358         int len_a = strlen(a);
2359         int len_b = strlen(b);
2360         int a_midlen, b_midlen;
2361         int qlen_a = quote_c_style(a, NULL, NULL, 0);
2362         int qlen_b = quote_c_style(b, NULL, NULL, 0);
2363
2364         if (qlen_a || qlen_b) {
2365                 quote_c_style(a, name, NULL, 0);
2366                 strbuf_addstr(name, " => ");
2367                 quote_c_style(b, name, NULL, 0);
2368                 return;
2369         }
2370
2371         /* Find common prefix */
2372         pfx_length = 0;
2373         while (*old_name && *new_name && *old_name == *new_name) {
2374                 if (*old_name == '/')
2375                         pfx_length = old_name - a + 1;
2376                 old_name++;
2377                 new_name++;
2378         }
2379
2380         /* Find common suffix */
2381         old_name = a + len_a;
2382         new_name = b + len_b;
2383         sfx_length = 0;
2384         /*
2385          * If there is a common prefix, it must end in a slash.  In
2386          * that case we let this loop run 1 into the prefix to see the
2387          * same slash.
2388          *
2389          * If there is no common prefix, we cannot do this as it would
2390          * underrun the input strings.
2391          */
2392         pfx_adjust_for_slash = (pfx_length ? 1 : 0);
2393         while (a + pfx_length - pfx_adjust_for_slash <= old_name &&
2394                b + pfx_length - pfx_adjust_for_slash <= new_name &&
2395                *old_name == *new_name) {
2396                 if (*old_name == '/')
2397                         sfx_length = len_a - (old_name - a);
2398                 old_name--;
2399                 new_name--;
2400         }
2401
2402         /*
2403          * pfx{mid-a => mid-b}sfx
2404          * {pfx-a => pfx-b}sfx
2405          * pfx{sfx-a => sfx-b}
2406          * name-a => name-b
2407          */
2408         a_midlen = len_a - pfx_length - sfx_length;
2409         b_midlen = len_b - pfx_length - sfx_length;
2410         if (a_midlen < 0)
2411                 a_midlen = 0;
2412         if (b_midlen < 0)
2413                 b_midlen = 0;
2414
2415         strbuf_grow(name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
2416         if (pfx_length + sfx_length) {
2417                 strbuf_add(name, a, pfx_length);
2418                 strbuf_addch(name, '{');
2419         }
2420         strbuf_add(name, a + pfx_length, a_midlen);
2421         strbuf_addstr(name, " => ");
2422         strbuf_add(name, b + pfx_length, b_midlen);
2423         if (pfx_length + sfx_length) {
2424                 strbuf_addch(name, '}');
2425                 strbuf_add(name, a + len_a - sfx_length, sfx_length);
2426         }
2427 }
2428
2429 struct diffstat_t {
2430         int nr;
2431         int alloc;
2432         struct diffstat_file {
2433                 char *from_name;
2434                 char *name;
2435                 char *print_name;
2436                 const char *comments;
2437                 unsigned is_unmerged:1;
2438                 unsigned is_binary:1;
2439                 unsigned is_renamed:1;
2440                 unsigned is_interesting:1;
2441                 uintmax_t added, deleted;
2442         } **files;
2443 };
2444
2445 static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
2446                                           const char *name_a,
2447                                           const char *name_b)
2448 {
2449         struct diffstat_file *x;
2450         x = xcalloc(1, sizeof(*x));
2451         ALLOC_GROW(diffstat->files, diffstat->nr + 1, diffstat->alloc);
2452         diffstat->files[diffstat->nr++] = x;
2453         if (name_b) {
2454                 x->from_name = xstrdup(name_a);
2455                 x->name = xstrdup(name_b);
2456                 x->is_renamed = 1;
2457         }
2458         else {
2459                 x->from_name = NULL;
2460                 x->name = xstrdup(name_a);
2461         }
2462         return x;
2463 }
2464
2465 static void diffstat_consume(void *priv, char *line, unsigned long len)
2466 {
2467         struct diffstat_t *diffstat = priv;
2468         struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
2469
2470         if (line[0] == '+')
2471                 x->added++;
2472         else if (line[0] == '-')
2473                 x->deleted++;
2474 }
2475
2476 const char mime_boundary_leader[] = "------------";
2477
2478 static int scale_linear(int it, int width, int max_change)
2479 {
2480         if (!it)
2481                 return 0;
2482         /*
2483          * make sure that at least one '-' or '+' is printed if
2484          * there is any change to this path. The easiest way is to
2485          * scale linearly as if the alloted width is one column shorter
2486          * than it is, and then add 1 to the result.
2487          */
2488         return 1 + (it * (width - 1) / max_change);
2489 }
2490
2491 static void show_graph(struct strbuf *out, char ch, int cnt,
2492                        const char *set, const char *reset)
2493 {
2494         if (cnt <= 0)
2495                 return;
2496         strbuf_addstr(out, set);
2497         strbuf_addchars(out, ch, cnt);
2498         strbuf_addstr(out, reset);
2499 }
2500
2501 static void fill_print_name(struct diffstat_file *file)
2502 {
2503         struct strbuf pname = STRBUF_INIT;
2504
2505         if (file->print_name)
2506                 return;
2507
2508         if (file->is_renamed)
2509                 pprint_rename(&pname, file->from_name, file->name);
2510         else
2511                 quote_c_style(file->name, &pname, NULL, 0);
2512
2513         if (file->comments)
2514                 strbuf_addf(&pname, " (%s)", file->comments);
2515
2516         file->print_name = strbuf_detach(&pname, NULL);
2517 }
2518
2519 static void print_stat_summary_inserts_deletes(struct diff_options *options,
2520                 int files, int insertions, int deletions)
2521 {
2522         struct strbuf sb = STRBUF_INIT;
2523
2524         if (!files) {
2525                 assert(insertions == 0 && deletions == 0);
2526                 emit_diff_symbol(options, DIFF_SYMBOL_STATS_SUMMARY_NO_FILES,
2527                                  NULL, 0, 0);
2528                 return;
2529         }
2530
2531         strbuf_addf(&sb,
2532                     (files == 1) ? " %d file changed" : " %d files changed",
2533                     files);
2534
2535         /*
2536          * For binary diff, the caller may want to print "x files
2537          * changed" with insertions == 0 && deletions == 0.
2538          *
2539          * Not omitting "0 insertions(+), 0 deletions(-)" in this case
2540          * is probably less confusing (i.e skip over "2 files changed
2541          * but nothing about added/removed lines? Is this a bug in Git?").
2542          */
2543         if (insertions || deletions == 0) {
2544                 strbuf_addf(&sb,
2545                             (insertions == 1) ? ", %d insertion(+)" : ", %d insertions(+)",
2546                             insertions);
2547         }
2548
2549         if (deletions || insertions == 0) {
2550                 strbuf_addf(&sb,
2551                             (deletions == 1) ? ", %d deletion(-)" : ", %d deletions(-)",
2552                             deletions);
2553         }
2554         strbuf_addch(&sb, '\n');
2555         emit_diff_symbol(options, DIFF_SYMBOL_STATS_SUMMARY_INSERTS_DELETES,
2556                          sb.buf, sb.len, 0);
2557         strbuf_release(&sb);
2558 }
2559
2560 void print_stat_summary(FILE *fp, int files,
2561                         int insertions, int deletions)
2562 {
2563         struct diff_options o;
2564         memset(&o, 0, sizeof(o));
2565         o.file = fp;
2566
2567         print_stat_summary_inserts_deletes(&o, files, insertions, deletions);
2568 }
2569
2570 static void show_stats(struct diffstat_t *data, struct diff_options *options)
2571 {
2572         int i, len, add, del, adds = 0, dels = 0;
2573         uintmax_t max_change = 0, max_len = 0;
2574         int total_files = data->nr, count;
2575         int width, name_width, graph_width, number_width = 0, bin_width = 0;
2576         const char *reset, *add_c, *del_c;
2577         int extra_shown = 0;
2578         const char *line_prefix = diff_line_prefix(options);
2579         struct strbuf out = STRBUF_INIT;
2580
2581         if (data->nr == 0)
2582                 return;
2583
2584         count = options->stat_count ? options->stat_count : data->nr;
2585
2586         reset = diff_get_color_opt(options, DIFF_RESET);
2587         add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
2588         del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
2589
2590         /*
2591          * Find the longest filename and max number of changes
2592          */
2593         for (i = 0; (i < count) && (i < data->nr); i++) {
2594                 struct diffstat_file *file = data->files[i];
2595                 uintmax_t change = file->added + file->deleted;
2596
2597                 if (!file->is_interesting && (change == 0)) {
2598                         count++; /* not shown == room for one more */
2599                         continue;
2600                 }
2601                 fill_print_name(file);
2602                 len = strlen(file->print_name);
2603                 if (max_len < len)
2604                         max_len = len;
2605
2606                 if (file->is_unmerged) {
2607                         /* "Unmerged" is 8 characters */
2608                         bin_width = bin_width < 8 ? 8 : bin_width;
2609                         continue;
2610                 }
2611                 if (file->is_binary) {
2612                         /* "Bin XXX -> YYY bytes" */
2613                         int w = 14 + decimal_width(file->added)
2614                                 + decimal_width(file->deleted);
2615                         bin_width = bin_width < w ? w : bin_width;
2616                         /* Display change counts aligned with "Bin" */
2617                         number_width = 3;
2618                         continue;
2619                 }
2620
2621                 if (max_change < change)
2622                         max_change = change;
2623         }
2624         count = i; /* where we can stop scanning in data->files[] */
2625
2626         /*
2627          * We have width = stat_width or term_columns() columns total.
2628          * We want a maximum of min(max_len, stat_name_width) for the name part.
2629          * We want a maximum of min(max_change, stat_graph_width) for the +- part.
2630          * We also need 1 for " " and 4 + decimal_width(max_change)
2631          * for " | NNNN " and one the empty column at the end, altogether
2632          * 6 + decimal_width(max_change).
2633          *
2634          * If there's not enough space, we will use the smaller of
2635          * stat_name_width (if set) and 5/8*width for the filename,
2636          * and the rest for constant elements + graph part, but no more
2637          * than stat_graph_width for the graph part.
2638          * (5/8 gives 50 for filename and 30 for the constant parts + graph
2639          * for the standard terminal size).
2640          *
2641          * In other words: stat_width limits the maximum width, and
2642          * stat_name_width fixes the maximum width of the filename,
2643          * and is also used to divide available columns if there
2644          * aren't enough.
2645          *
2646          * Binary files are displayed with "Bin XXX -> YYY bytes"
2647          * instead of the change count and graph. This part is treated
2648          * similarly to the graph part, except that it is not
2649          * "scaled". If total width is too small to accommodate the
2650          * guaranteed minimum width of the filename part and the
2651          * separators and this message, this message will "overflow"
2652          * making the line longer than the maximum width.
2653          */
2654
2655         if (options->stat_width == -1)
2656                 width = term_columns() - strlen(line_prefix);
2657         else
2658                 width = options->stat_width ? options->stat_width : 80;
2659         number_width = decimal_width(max_change) > number_width ?
2660                 decimal_width(max_change) : number_width;
2661
2662         if (options->stat_graph_width == -1)
2663                 options->stat_graph_width = diff_stat_graph_width;
2664
2665         /*
2666          * Guarantee 3/8*16==6 for the graph part
2667          * and 5/8*16==10 for the filename part
2668          */
2669         if (width < 16 + 6 + number_width)
2670                 width = 16 + 6 + number_width;
2671
2672         /*
2673          * First assign sizes that are wanted, ignoring available width.
2674          * strlen("Bin XXX -> YYY bytes") == bin_width, and the part
2675          * starting from "XXX" should fit in graph_width.
2676          */
2677         graph_width = max_change + 4 > bin_width ? max_change : bin_width - 4;
2678         if (options->stat_graph_width &&
2679             options->stat_graph_width < graph_width)
2680                 graph_width = options->stat_graph_width;
2681
2682         name_width = (options->stat_name_width > 0 &&
2683                       options->stat_name_width < max_len) ?
2684                 options->stat_name_width : max_len;
2685
2686         /*
2687          * Adjust adjustable widths not to exceed maximum width
2688          */
2689         if (name_width + number_width + 6 + graph_width > width) {
2690                 if (graph_width > width * 3/8 - number_width - 6) {
2691                         graph_width = width * 3/8 - number_width - 6;
2692                         if (graph_width < 6)
2693                                 graph_width = 6;
2694                 }
2695
2696                 if (options->stat_graph_width &&
2697                     graph_width > options->stat_graph_width)
2698                         graph_width = options->stat_graph_width;
2699                 if (name_width > width - number_width - 6 - graph_width)
2700                         name_width = width - number_width - 6 - graph_width;
2701                 else
2702                         graph_width = width - number_width - 6 - name_width;
2703         }
2704
2705         /*
2706          * From here name_width is the width of the name area,
2707          * and graph_width is the width of the graph area.
2708          * max_change is used to scale graph properly.
2709          */
2710         for (i = 0; i < count; i++) {
2711                 const char *prefix = "";
2712                 struct diffstat_file *file = data->files[i];
2713                 char *name = file->print_name;
2714                 uintmax_t added = file->added;
2715                 uintmax_t deleted = file->deleted;
2716                 int name_len;
2717
2718                 if (!file->is_interesting && (added + deleted == 0))
2719                         continue;
2720
2721                 /*
2722                  * "scale" the filename
2723                  */
2724                 len = name_width;
2725                 name_len = strlen(name);
2726                 if (name_width < name_len) {
2727                         char *slash;
2728                         prefix = "...";
2729                         len -= 3;
2730                         name += name_len - len;
2731                         slash = strchr(name, '/');
2732                         if (slash)
2733                                 name = slash;
2734                 }
2735
2736                 if (file->is_binary) {
2737                         strbuf_addf(&out, " %s%-*s |", prefix, len, name);
2738                         strbuf_addf(&out, " %*s", number_width, "Bin");
2739                         if (!added && !deleted) {
2740                                 strbuf_addch(&out, '\n');
2741                                 emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2742                                                  out.buf, out.len, 0);
2743                                 strbuf_reset(&out);
2744                                 continue;
2745                         }
2746                         strbuf_addf(&out, " %s%"PRIuMAX"%s",
2747                                 del_c, deleted, reset);
2748                         strbuf_addstr(&out, " -> ");
2749                         strbuf_addf(&out, "%s%"PRIuMAX"%s",
2750                                 add_c, added, reset);
2751                         strbuf_addstr(&out, " bytes\n");
2752                         emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2753                                          out.buf, out.len, 0);
2754                         strbuf_reset(&out);
2755                         continue;
2756                 }
2757                 else if (file->is_unmerged) {
2758                         strbuf_addf(&out, " %s%-*s |", prefix, len, name);
2759                         strbuf_addstr(&out, " Unmerged\n");
2760                         emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2761                                          out.buf, out.len, 0);
2762                         strbuf_reset(&out);
2763                         continue;
2764                 }
2765
2766                 /*
2767                  * scale the add/delete
2768                  */
2769                 add = added;
2770                 del = deleted;
2771
2772                 if (graph_width <= max_change) {
2773                         int total = scale_linear(add + del, graph_width, max_change);
2774                         if (total < 2 && add && del)
2775                                 /* width >= 2 due to the sanity check */
2776                                 total = 2;
2777                         if (add < del) {
2778                                 add = scale_linear(add, graph_width, max_change);
2779                                 del = total - add;
2780                         } else {
2781                                 del = scale_linear(del, graph_width, max_change);
2782                                 add = total - del;
2783                         }
2784                 }
2785                 strbuf_addf(&out, " %s%-*s |", prefix, len, name);
2786                 strbuf_addf(&out, " %*"PRIuMAX"%s",
2787                         number_width, added + deleted,
2788                         added + deleted ? " " : "");
2789                 show_graph(&out, '+', add, add_c, reset);
2790                 show_graph(&out, '-', del, del_c, reset);
2791                 strbuf_addch(&out, '\n');
2792                 emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2793                                  out.buf, out.len, 0);
2794                 strbuf_reset(&out);
2795         }
2796
2797         for (i = 0; i < data->nr; i++) {
2798                 struct diffstat_file *file = data->files[i];
2799                 uintmax_t added = file->added;
2800                 uintmax_t deleted = file->deleted;
2801
2802                 if (file->is_unmerged ||
2803                     (!file->is_interesting && (added + deleted == 0))) {
2804                         total_files--;
2805                         continue;
2806                 }
2807
2808                 if (!file->is_binary) {
2809                         adds += added;
2810                         dels += deleted;
2811                 }
2812                 if (i < count)
2813                         continue;
2814                 if (!extra_shown)
2815                         emit_diff_symbol(options,
2816                                          DIFF_SYMBOL_STATS_SUMMARY_ABBREV,
2817                                          NULL, 0, 0);
2818                 extra_shown = 1;
2819         }
2820
2821         print_stat_summary_inserts_deletes(options, total_files, adds, dels);
2822         strbuf_release(&out);
2823 }
2824
2825 static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
2826 {
2827         int i, adds = 0, dels = 0, total_files = data->nr;
2828
2829         if (data->nr == 0)
2830                 return;
2831
2832         for (i = 0; i < data->nr; i++) {
2833                 int added = data->files[i]->added;
2834                 int deleted = data->files[i]->deleted;
2835
2836                 if (data->files[i]->is_unmerged ||
2837                     (!data->files[i]->is_interesting && (added + deleted == 0))) {
2838                         total_files--;
2839                 } else if (!data->files[i]->is_binary) { /* don't count bytes */
2840                         adds += added;
2841                         dels += deleted;
2842                 }
2843         }
2844         print_stat_summary_inserts_deletes(options, total_files, adds, dels);
2845 }
2846
2847 static void show_numstat(struct diffstat_t *data, struct diff_options *options)
2848 {
2849         int i;
2850
2851         if (data->nr == 0)
2852                 return;
2853
2854         for (i = 0; i < data->nr; i++) {
2855                 struct diffstat_file *file = data->files[i];
2856
2857                 fprintf(options->file, "%s", diff_line_prefix(options));
2858
2859                 if (file->is_binary)
2860                         fprintf(options->file, "-\t-\t");
2861                 else
2862                         fprintf(options->file,
2863                                 "%"PRIuMAX"\t%"PRIuMAX"\t",
2864                                 file->added, file->deleted);
2865                 if (options->line_termination) {
2866                         fill_print_name(file);
2867                         if (!file->is_renamed)
2868                                 write_name_quoted(file->name, options->file,
2869                                                   options->line_termination);
2870                         else {
2871                                 fputs(file->print_name, options->file);
2872                                 putc(options->line_termination, options->file);
2873                         }
2874                 } else {
2875                         if (file->is_renamed) {
2876                                 putc('\0', options->file);
2877                                 write_name_quoted(file->from_name, options->file, '\0');
2878                         }
2879                         write_name_quoted(file->name, options->file, '\0');
2880                 }
2881         }
2882 }
2883
2884 struct dirstat_file {
2885         const char *name;
2886         unsigned long changed;
2887 };
2888
2889 struct dirstat_dir {
2890         struct dirstat_file *files;
2891         int alloc, nr, permille, cumulative;
2892 };
2893
2894 static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
2895                 unsigned long changed, const char *base, int baselen)
2896 {
2897         unsigned long sum_changes = 0;
2898         unsigned int sources = 0;
2899         const char *line_prefix = diff_line_prefix(opt);
2900
2901         while (dir->nr) {
2902                 struct dirstat_file *f = dir->files;
2903                 int namelen = strlen(f->name);
2904                 unsigned long changes;
2905                 char *slash;
2906
2907                 if (namelen < baselen)
2908                         break;
2909                 if (memcmp(f->name, base, baselen))
2910                         break;
2911                 slash = strchr(f->name + baselen, '/');
2912                 if (slash) {
2913                         int newbaselen = slash + 1 - f->name;
2914                         changes = gather_dirstat(opt, dir, changed, f->name, newbaselen);
2915                         sources++;
2916                 } else {
2917                         changes = f->changed;
2918                         dir->files++;
2919                         dir->nr--;
2920                         sources += 2;
2921                 }
2922                 sum_changes += changes;
2923         }
2924
2925         /*
2926          * We don't report dirstat's for
2927          *  - the top level
2928          *  - or cases where everything came from a single directory
2929          *    under this directory (sources == 1).
2930          */
2931         if (baselen && sources != 1) {
2932                 if (sum_changes) {
2933                         int permille = sum_changes * 1000 / changed;
2934                         if (permille >= dir->permille) {
2935                                 fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
2936                                         permille / 10, permille % 10, baselen, base);
2937                                 if (!dir->cumulative)
2938                                         return 0;
2939                         }
2940                 }
2941         }
2942         return sum_changes;
2943 }
2944
2945 static int dirstat_compare(const void *_a, const void *_b)
2946 {
2947         const struct dirstat_file *a = _a;
2948         const struct dirstat_file *b = _b;
2949         return strcmp(a->name, b->name);
2950 }
2951
2952 static void show_dirstat(struct diff_options *options)
2953 {
2954         int i;
2955         unsigned long changed;
2956         struct dirstat_dir dir;
2957         struct diff_queue_struct *q = &diff_queued_diff;
2958
2959         dir.files = NULL;
2960         dir.alloc = 0;
2961         dir.nr = 0;
2962         dir.permille = options->dirstat_permille;
2963         dir.cumulative = options->flags.dirstat_cumulative;
2964
2965         changed = 0;
2966         for (i = 0; i < q->nr; i++) {
2967                 struct diff_filepair *p = q->queue[i];
2968                 const char *name;
2969                 unsigned long copied, added, damage;
2970
2971                 name = p->two->path ? p->two->path : p->one->path;
2972
2973                 if (p->one->oid_valid && p->two->oid_valid &&
2974                     oideq(&p->one->oid, &p->two->oid)) {
2975                         /*
2976                          * The SHA1 has not changed, so pre-/post-content is
2977                          * identical. We can therefore skip looking at the
2978                          * file contents altogether.
2979                          */
2980                         damage = 0;
2981                         goto found_damage;
2982                 }
2983
2984                 if (options->flags.dirstat_by_file) {
2985                         /*
2986                          * In --dirstat-by-file mode, we don't really need to
2987                          * look at the actual file contents at all.
2988                          * The fact that the SHA1 changed is enough for us to
2989                          * add this file to the list of results
2990                          * (with each file contributing equal damage).
2991                          */
2992                         damage = 1;
2993                         goto found_damage;
2994                 }
2995
2996                 if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
2997                         diff_populate_filespec(options->repo, p->one, 0);
2998                         diff_populate_filespec(options->repo, p->two, 0);
2999                         diffcore_count_changes(options->repo,
3000                                                p->one, p->two, NULL, NULL,
3001                                                &copied, &added);
3002                         diff_free_filespec_data(p->one);
3003                         diff_free_filespec_data(p->two);
3004                 } else if (DIFF_FILE_VALID(p->one)) {
3005                         diff_populate_filespec(options->repo, p->one, CHECK_SIZE_ONLY);
3006                         copied = added = 0;
3007                         diff_free_filespec_data(p->one);
3008                 } else if (DIFF_FILE_VALID(p->two)) {
3009                         diff_populate_filespec(options->repo, p->two, CHECK_SIZE_ONLY);
3010                         copied = 0;
3011                         added = p->two->size;
3012                         diff_free_filespec_data(p->two);
3013                 } else
3014                         continue;
3015
3016                 /*
3017                  * Original minus copied is the removed material,
3018                  * added is the new material.  They are both damages
3019                  * made to the preimage.
3020                  * If the resulting damage is zero, we know that
3021                  * diffcore_count_changes() considers the two entries to
3022                  * be identical, but since the oid changed, we
3023                  * know that there must have been _some_ kind of change,
3024                  * so we force all entries to have damage > 0.
3025                  */
3026                 damage = (p->one->size - copied) + added;
3027                 if (!damage)
3028                         damage = 1;
3029
3030 found_damage:
3031                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
3032                 dir.files[dir.nr].name = name;
3033                 dir.files[dir.nr].changed = damage;
3034                 changed += damage;
3035                 dir.nr++;
3036         }
3037
3038         /* This can happen even with many files, if everything was renames */
3039         if (!changed)
3040                 return;
3041
3042         /* Show all directories with more than x% of the changes */
3043         QSORT(dir.files, dir.nr, dirstat_compare);
3044         gather_dirstat(options, &dir, changed, "", 0);
3045 }
3046
3047 static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
3048 {
3049         int i;
3050         unsigned long changed;
3051         struct dirstat_dir dir;
3052
3053         if (data->nr == 0)
3054                 return;
3055
3056         dir.files = NULL;
3057         dir.alloc = 0;
3058         dir.nr = 0;
3059         dir.permille = options->dirstat_permille;
3060         dir.cumulative = options->flags.dirstat_cumulative;
3061
3062         changed = 0;
3063         for (i = 0; i < data->nr; i++) {
3064                 struct diffstat_file *file = data->files[i];
3065                 unsigned long damage = file->added + file->deleted;
3066                 if (file->is_binary)
3067                         /*
3068                          * binary files counts bytes, not lines. Must find some
3069                          * way to normalize binary bytes vs. textual lines.
3070                          * The following heuristic assumes that there are 64
3071                          * bytes per "line".
3072                          * This is stupid and ugly, but very cheap...
3073                          */
3074                         damage = DIV_ROUND_UP(damage, 64);
3075                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
3076                 dir.files[dir.nr].name = file->name;
3077                 dir.files[dir.nr].changed = damage;
3078                 changed += damage;
3079                 dir.nr++;
3080         }
3081
3082         /* This can happen even with many files, if everything was renames */
3083         if (!changed)
3084                 return;
3085
3086         /* Show all directories with more than x% of the changes */
3087         QSORT(dir.files, dir.nr, dirstat_compare);
3088         gather_dirstat(options, &dir, changed, "", 0);
3089 }
3090
3091 static void free_diffstat_info(struct diffstat_t *diffstat)
3092 {
3093         int i;
3094         for (i = 0; i < diffstat->nr; i++) {
3095                 struct diffstat_file *f = diffstat->files[i];
3096                 free(f->print_name);
3097                 free(f->name);
3098                 free(f->from_name);
3099                 free(f);
3100         }
3101         free(diffstat->files);
3102 }
3103
3104 struct checkdiff_t {
3105         const char *filename;
3106         int lineno;
3107         int conflict_marker_size;
3108         struct diff_options *o;
3109         unsigned ws_rule;
3110         unsigned status;
3111 };
3112
3113 static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
3114 {
3115         char firstchar;
3116         int cnt;
3117
3118         if (len < marker_size + 1)
3119                 return 0;
3120         firstchar = line[0];
3121         switch (firstchar) {
3122         case '=': case '>': case '<': case '|':
3123                 break;
3124         default:
3125                 return 0;
3126         }
3127         for (cnt = 1; cnt < marker_size; cnt++)
3128                 if (line[cnt] != firstchar)
3129                         return 0;
3130         /* line[1] thru line[marker_size-1] are same as firstchar */
3131         if (len < marker_size + 1 || !isspace(line[marker_size]))
3132                 return 0;
3133         return 1;
3134 }
3135
3136 static void checkdiff_consume_hunk(void *priv,
3137                                    long ob, long on, long nb, long nn,
3138                                    const char *func, long funclen)
3139
3140 {
3141         struct checkdiff_t *data = priv;
3142         data->lineno = nb - 1;
3143 }
3144
3145 static void checkdiff_consume(void *priv, char *line, unsigned long len)
3146 {
3147         struct checkdiff_t *data = priv;
3148         int marker_size = data->conflict_marker_size;
3149         const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
3150         const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
3151         const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
3152         char *err;
3153         const char *line_prefix;
3154
3155         assert(data->o);
3156         line_prefix = diff_line_prefix(data->o);
3157
3158         if (line[0] == '+') {
3159                 unsigned bad;
3160                 data->lineno++;
3161                 if (is_conflict_marker(line + 1, marker_size, len - 1)) {
3162                         data->status |= 1;
3163                         fprintf(data->o->file,
3164                                 "%s%s:%d: leftover conflict marker\n",
3165                                 line_prefix, data->filename, data->lineno);
3166                 }
3167                 bad = ws_check(line + 1, len - 1, data->ws_rule);
3168                 if (!bad)
3169                         return;
3170                 data->status |= bad;
3171                 err = whitespace_error_string(bad);
3172                 fprintf(data->o->file, "%s%s:%d: %s.\n",
3173                         line_prefix, data->filename, data->lineno, err);
3174                 free(err);
3175                 emit_line(data->o, set, reset, line, 1);
3176                 ws_check_emit(line + 1, len - 1, data->ws_rule,
3177                               data->o->file, set, reset, ws);
3178         } else if (line[0] == ' ') {
3179                 data->lineno++;
3180         }
3181 }
3182
3183 static unsigned char *deflate_it(char *data,
3184                                  unsigned long size,
3185                                  unsigned long *result_size)
3186 {
3187         int bound;
3188         unsigned char *deflated;
3189         git_zstream stream;
3190
3191         git_deflate_init(&stream, zlib_compression_level);
3192         bound = git_deflate_bound(&stream, size);
3193         deflated = xmalloc(bound);
3194         stream.next_out = deflated;
3195         stream.avail_out = bound;
3196
3197         stream.next_in = (unsigned char *)data;
3198         stream.avail_in = size;
3199         while (git_deflate(&stream, Z_FINISH) == Z_OK)
3200                 ; /* nothing */
3201         git_deflate_end(&stream);
3202         *result_size = stream.total_out;
3203         return deflated;
3204 }
3205
3206 static void emit_binary_diff_body(struct diff_options *o,
3207                                   mmfile_t *one, mmfile_t *two)
3208 {
3209         void *cp;
3210         void *delta;
3211         void *deflated;
3212         void *data;
3213         unsigned long orig_size;
3214         unsigned long delta_size;
3215         unsigned long deflate_size;
3216         unsigned long data_size;
3217
3218         /* We could do deflated delta, or we could do just deflated two,
3219          * whichever is smaller.
3220          */
3221         delta = NULL;
3222         deflated = deflate_it(two->ptr, two->size, &deflate_size);
3223         if (one->size && two->size) {
3224                 delta = diff_delta(one->ptr, one->size,
3225                                    two->ptr, two->size,
3226                                    &delta_size, deflate_size);
3227                 if (delta) {
3228                         void *to_free = delta;
3229                         orig_size = delta_size;
3230                         delta = deflate_it(delta, delta_size, &delta_size);
3231                         free(to_free);
3232                 }
3233         }
3234
3235         if (delta && delta_size < deflate_size) {
3236                 char *s = xstrfmt("%"PRIuMAX , (uintmax_t)orig_size);
3237                 emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_HEADER_DELTA,
3238                                  s, strlen(s), 0);
3239                 free(s);
3240                 free(deflated);
3241                 data = delta;
3242                 data_size = delta_size;
3243         } else {
3244                 char *s = xstrfmt("%lu", two->size);
3245                 emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_HEADER_LITERAL,
3246                                  s, strlen(s), 0);
3247                 free(s);
3248                 free(delta);
3249                 data = deflated;
3250                 data_size = deflate_size;
3251         }
3252
3253         /* emit data encoded in base85 */
3254         cp = data;
3255         while (data_size) {
3256                 int len;
3257                 int bytes = (52 < data_size) ? 52 : data_size;
3258                 char line[71];
3259                 data_size -= bytes;
3260                 if (bytes <= 26)
3261                         line[0] = bytes + 'A' - 1;
3262                 else
3263                         line[0] = bytes - 26 + 'a' - 1;
3264                 encode_85(line + 1, cp, bytes);
3265                 cp = (char *) cp + bytes;
3266
3267                 len = strlen(line);
3268                 line[len++] = '\n';
3269                 line[len] = '\0';
3270
3271                 emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_BODY,
3272                                  line, len, 0);
3273         }
3274         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_FOOTER, NULL, 0, 0);
3275         free(data);
3276 }
3277
3278 static void emit_binary_diff(struct diff_options *o,
3279                              mmfile_t *one, mmfile_t *two)
3280 {
3281         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_HEADER, NULL, 0, 0);
3282         emit_binary_diff_body(o, one, two);
3283         emit_binary_diff_body(o, two, one);
3284 }
3285
3286 int diff_filespec_is_binary(struct repository *r,
3287                             struct diff_filespec *one)
3288 {
3289         if (one->is_binary == -1) {
3290                 diff_filespec_load_driver(one, r->index);
3291                 if (one->driver->binary != -1)
3292                         one->is_binary = one->driver->binary;
3293                 else {
3294                         if (!one->data && DIFF_FILE_VALID(one))
3295                                 diff_populate_filespec(r, one, CHECK_BINARY);
3296                         if (one->is_binary == -1 && one->data)
3297                                 one->is_binary = buffer_is_binary(one->data,
3298                                                 one->size);
3299                         if (one->is_binary == -1)
3300                                 one->is_binary = 0;
3301                 }
3302         }
3303         return one->is_binary;
3304 }
3305
3306 static const struct userdiff_funcname *
3307 diff_funcname_pattern(struct diff_options *o, struct diff_filespec *one)
3308 {
3309         diff_filespec_load_driver(one, o->repo->index);
3310         return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
3311 }
3312
3313 void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
3314 {
3315         if (!options->a_prefix)
3316                 options->a_prefix = a;
3317         if (!options->b_prefix)
3318                 options->b_prefix = b;
3319 }
3320
3321 struct userdiff_driver *get_textconv(struct index_state *istate,
3322                                      struct diff_filespec *one)
3323 {
3324         if (!DIFF_FILE_VALID(one))
3325                 return NULL;
3326
3327         diff_filespec_load_driver(one, istate);
3328         return userdiff_get_textconv(one->driver);
3329 }
3330
3331 static void builtin_diff(const char *name_a,
3332                          const char *name_b,
3333                          struct diff_filespec *one,
3334                          struct diff_filespec *two,
3335                          const char *xfrm_msg,
3336                          int must_show_header,
3337                          struct diff_options *o,
3338                          int complete_rewrite)
3339 {
3340         mmfile_t mf1, mf2;
3341         const char *lbl[2];
3342         char *a_one, *b_two;
3343         const char *meta = diff_get_color_opt(o, DIFF_METAINFO);
3344         const char *reset = diff_get_color_opt(o, DIFF_RESET);
3345         const char *a_prefix, *b_prefix;
3346         struct userdiff_driver *textconv_one = NULL;
3347         struct userdiff_driver *textconv_two = NULL;
3348         struct strbuf header = STRBUF_INIT;
3349         const char *line_prefix = diff_line_prefix(o);
3350
3351         diff_set_mnemonic_prefix(o, "a/", "b/");
3352         if (o->flags.reverse_diff) {
3353                 a_prefix = o->b_prefix;
3354                 b_prefix = o->a_prefix;
3355         } else {
3356                 a_prefix = o->a_prefix;
3357                 b_prefix = o->b_prefix;
3358         }
3359
3360         if (o->submodule_format == DIFF_SUBMODULE_LOG &&
3361             (!one->mode || S_ISGITLINK(one->mode)) &&
3362             (!two->mode || S_ISGITLINK(two->mode))) {
3363                 show_submodule_summary(o, one->path ? one->path : two->path,
3364                                 &one->oid, &two->oid,
3365                                 two->dirty_submodule);
3366                 return;
3367         } else if (o->submodule_format == DIFF_SUBMODULE_INLINE_DIFF &&
3368                    (!one->mode || S_ISGITLINK(one->mode)) &&
3369                    (!two->mode || S_ISGITLINK(two->mode))) {
3370                 show_submodule_inline_diff(o, one->path ? one->path : two->path,
3371                                 &one->oid, &two->oid,
3372                                 two->dirty_submodule);
3373                 return;
3374         }
3375
3376         if (o->flags.allow_textconv) {
3377                 textconv_one = get_textconv(o->repo->index, one);
3378                 textconv_two = get_textconv(o->repo->index, two);
3379         }
3380
3381         /* Never use a non-valid filename anywhere if at all possible */
3382         name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
3383         name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
3384
3385         a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
3386         b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
3387         lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
3388         lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
3389         strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, meta, a_one, b_two, reset);
3390         if (lbl[0][0] == '/') {
3391                 /* /dev/null */
3392                 strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, meta, two->mode, reset);
3393                 if (xfrm_msg)
3394                         strbuf_addstr(&header, xfrm_msg);
3395                 must_show_header = 1;
3396         }
3397         else if (lbl[1][0] == '/') {
3398                 strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, meta, one->mode, reset);
3399                 if (xfrm_msg)
3400                         strbuf_addstr(&header, xfrm_msg);
3401                 must_show_header = 1;
3402         }
3403         else {
3404                 if (one->mode != two->mode) {
3405                         strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, meta, one->mode, reset);
3406                         strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, meta, two->mode, reset);
3407                         must_show_header = 1;
3408                 }
3409                 if (xfrm_msg)
3410                         strbuf_addstr(&header, xfrm_msg);
3411
3412                 /*
3413                  * we do not run diff between different kind
3414                  * of objects.
3415                  */
3416                 if ((one->mode ^ two->mode) & S_IFMT)
3417                         goto free_ab_and_return;
3418                 if (complete_rewrite &&
3419                     (textconv_one || !diff_filespec_is_binary(o->repo, one)) &&
3420                     (textconv_two || !diff_filespec_is_binary(o->repo, two))) {
3421                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3422                                          header.buf, header.len, 0);
3423                         strbuf_reset(&header);
3424                         emit_rewrite_diff(name_a, name_b, one, two,
3425                                           textconv_one, textconv_two, o);
3426                         o->found_changes = 1;
3427                         goto free_ab_and_return;
3428                 }
3429         }
3430
3431         if (o->irreversible_delete && lbl[1][0] == '/') {
3432                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER, header.buf,
3433                                  header.len, 0);
3434                 strbuf_reset(&header);
3435                 goto free_ab_and_return;
3436         } else if (!o->flags.text &&
3437                    ( (!textconv_one && diff_filespec_is_binary(o->repo, one)) ||
3438                      (!textconv_two && diff_filespec_is_binary(o->repo, two)) )) {
3439                 struct strbuf sb = STRBUF_INIT;
3440                 if (!one->data && !two->data &&
3441                     S_ISREG(one->mode) && S_ISREG(two->mode) &&
3442                     !o->flags.binary) {
3443                         if (oideq(&one->oid, &two->oid)) {
3444                                 if (must_show_header)
3445                                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3446                                                          header.buf, header.len,
3447                                                          0);
3448                                 goto free_ab_and_return;
3449                         }
3450                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3451                                          header.buf, header.len, 0);
3452                         strbuf_addf(&sb, "%sBinary files %s and %s differ\n",
3453                                     diff_line_prefix(o), lbl[0], lbl[1]);
3454                         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_FILES,
3455                                          sb.buf, sb.len, 0);
3456                         strbuf_release(&sb);
3457                         goto free_ab_and_return;
3458                 }
3459                 if (fill_mmfile(o->repo, &mf1, one) < 0 ||
3460                     fill_mmfile(o->repo, &mf2, two) < 0)
3461                         die("unable to read files to diff");
3462                 /* Quite common confusing case */
3463                 if (mf1.size == mf2.size &&
3464                     !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
3465                         if (must_show_header)
3466                                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3467                                                  header.buf, header.len, 0);
3468                         goto free_ab_and_return;
3469                 }
3470                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER, header.buf, header.len, 0);
3471                 strbuf_reset(&header);
3472                 if (o->flags.binary)
3473                         emit_binary_diff(o, &mf1, &mf2);
3474                 else {
3475                         strbuf_addf(&sb, "%sBinary files %s and %s differ\n",
3476                                     diff_line_prefix(o), lbl[0], lbl[1]);
3477                         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_FILES,
3478                                          sb.buf, sb.len, 0);
3479                         strbuf_release(&sb);
3480                 }
3481                 o->found_changes = 1;
3482         } else {
3483                 /* Crazy xdl interfaces.. */
3484                 const char *diffopts = getenv("GIT_DIFF_OPTS");
3485                 const char *v;
3486                 xpparam_t xpp;
3487                 xdemitconf_t xecfg;
3488                 struct emit_callback ecbdata;
3489                 const struct userdiff_funcname *pe;
3490
3491                 if (must_show_header) {
3492                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3493                                          header.buf, header.len, 0);
3494                         strbuf_reset(&header);
3495                 }
3496
3497                 mf1.size = fill_textconv(o->repo, textconv_one, one, &mf1.ptr);
3498                 mf2.size = fill_textconv(o->repo, textconv_two, two, &mf2.ptr);
3499
3500                 pe = diff_funcname_pattern(o, one);
3501                 if (!pe)
3502                         pe = diff_funcname_pattern(o, two);
3503
3504                 memset(&xpp, 0, sizeof(xpp));
3505                 memset(&xecfg, 0, sizeof(xecfg));
3506                 memset(&ecbdata, 0, sizeof(ecbdata));
3507                 if (o->flags.suppress_diff_headers)
3508                         lbl[0] = NULL;
3509                 ecbdata.label_path = lbl;
3510                 ecbdata.color_diff = want_color(o->use_color);
3511                 ecbdata.ws_rule = whitespace_rule(o->repo->index, name_b);
3512                 if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
3513                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
3514                 ecbdata.opt = o;
3515                 if (header.len && !o->flags.suppress_diff_headers)
3516                         ecbdata.header = &header;
3517                 xpp.flags = o->xdl_opts;
3518                 xpp.anchors = o->anchors;
3519                 xpp.anchors_nr = o->anchors_nr;
3520                 xecfg.ctxlen = o->context;
3521                 xecfg.interhunkctxlen = o->interhunkcontext;
3522                 xecfg.flags = XDL_EMIT_FUNCNAMES;
3523                 if (o->flags.funccontext)
3524                         xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
3525                 if (pe)
3526                         xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
3527                 if (!diffopts)
3528                         ;
3529                 else if (skip_prefix(diffopts, "--unified=", &v))
3530                         xecfg.ctxlen = strtoul(v, NULL, 10);
3531                 else if (skip_prefix(diffopts, "-u", &v))
3532                         xecfg.ctxlen = strtoul(v, NULL, 10);
3533                 if (o->word_diff)
3534                         init_diff_words_data(&ecbdata, o, one, two);
3535                 if (xdi_diff_outf(&mf1, &mf2, NULL, fn_out_consume,
3536                                   &ecbdata, &xpp, &xecfg))
3537                         die("unable to generate diff for %s", one->path);
3538                 if (o->word_diff)
3539                         free_diff_words_data(&ecbdata);
3540                 if (textconv_one)
3541                         free(mf1.ptr);
3542                 if (textconv_two)
3543                         free(mf2.ptr);
3544                 xdiff_clear_find_func(&xecfg);
3545         }
3546
3547  free_ab_and_return:
3548         strbuf_release(&header);
3549         diff_free_filespec_data(one);
3550         diff_free_filespec_data(two);
3551         free(a_one);
3552         free(b_two);
3553         return;
3554 }
3555
3556 static char *get_compact_summary(const struct diff_filepair *p, int is_renamed)
3557 {
3558         if (!is_renamed) {
3559                 if (p->status == DIFF_STATUS_ADDED) {
3560                         if (S_ISLNK(p->two->mode))
3561                                 return "new +l";
3562                         else if ((p->two->mode & 0777) == 0755)
3563                                 return "new +x";
3564                         else
3565                                 return "new";
3566                 } else if (p->status == DIFF_STATUS_DELETED)
3567                         return "gone";
3568         }
3569         if (S_ISLNK(p->one->mode) && !S_ISLNK(p->two->mode))
3570                 return "mode -l";
3571         else if (!S_ISLNK(p->one->mode) && S_ISLNK(p->two->mode))
3572                 return "mode +l";
3573         else if ((p->one->mode & 0777) == 0644 &&
3574                  (p->two->mode & 0777) == 0755)
3575                 return "mode +x";
3576         else if ((p->one->mode & 0777) == 0755 &&
3577                  (p->two->mode & 0777) == 0644)
3578                 return "mode -x";
3579         return NULL;
3580 }
3581
3582 static void builtin_diffstat(const char *name_a, const char *name_b,
3583                              struct diff_filespec *one,
3584                              struct diff_filespec *two,
3585                              struct diffstat_t *diffstat,
3586                              struct diff_options *o,
3587                              struct diff_filepair *p)
3588 {
3589         mmfile_t mf1, mf2;
3590         struct diffstat_file *data;
3591         int same_contents;
3592         int complete_rewrite = 0;
3593
3594         if (!DIFF_PAIR_UNMERGED(p)) {
3595                 if (p->status == DIFF_STATUS_MODIFIED && p->score)
3596                         complete_rewrite = 1;
3597         }
3598
3599         data = diffstat_add(diffstat, name_a, name_b);
3600         data->is_interesting = p->status != DIFF_STATUS_UNKNOWN;
3601         if (o->flags.stat_with_summary)
3602                 data->comments = get_compact_summary(p, data->is_renamed);
3603
3604         if (!one || !two) {
3605                 data->is_unmerged = 1;
3606                 return;
3607         }
3608
3609         same_contents = oideq(&one->oid, &two->oid);
3610
3611         if (diff_filespec_is_binary(o->repo, one) ||
3612             diff_filespec_is_binary(o->repo, two)) {
3613                 data->is_binary = 1;
3614                 if (same_contents) {
3615                         data->added = 0;
3616                         data->deleted = 0;
3617                 } else {
3618                         data->added = diff_filespec_size(o->repo, two);
3619                         data->deleted = diff_filespec_size(o->repo, one);
3620                 }
3621         }
3622
3623         else if (complete_rewrite) {
3624                 diff_populate_filespec(o->repo, one, 0);
3625                 diff_populate_filespec(o->repo, two, 0);
3626                 data->deleted = count_lines(one->data, one->size);
3627                 data->added = count_lines(two->data, two->size);
3628         }
3629
3630         else if (!same_contents) {
3631                 /* Crazy xdl interfaces.. */
3632                 xpparam_t xpp;
3633                 xdemitconf_t xecfg;
3634
3635                 if (fill_mmfile(o->repo, &mf1, one) < 0 ||
3636                     fill_mmfile(o->repo, &mf2, two) < 0)
3637                         die("unable to read files to diff");
3638
3639                 memset(&xpp, 0, sizeof(xpp));
3640                 memset(&xecfg, 0, sizeof(xecfg));
3641                 xpp.flags = o->xdl_opts;
3642                 xpp.anchors = o->anchors;
3643                 xpp.anchors_nr = o->anchors_nr;
3644                 xecfg.ctxlen = o->context;
3645                 xecfg.interhunkctxlen = o->interhunkcontext;
3646                 if (xdi_diff_outf(&mf1, &mf2, discard_hunk_line,
3647                                   diffstat_consume, diffstat, &xpp, &xecfg))
3648                         die("unable to generate diffstat for %s", one->path);
3649         }
3650
3651         diff_free_filespec_data(one);
3652         diff_free_filespec_data(two);
3653 }
3654
3655 static void builtin_checkdiff(const char *name_a, const char *name_b,
3656                               const char *attr_path,
3657                               struct diff_filespec *one,
3658                               struct diff_filespec *two,
3659                               struct diff_options *o)
3660 {
3661         mmfile_t mf1, mf2;
3662         struct checkdiff_t data;
3663
3664         if (!two)
3665                 return;
3666
3667         memset(&data, 0, sizeof(data));
3668         data.filename = name_b ? name_b : name_a;
3669         data.lineno = 0;
3670         data.o = o;
3671         data.ws_rule = whitespace_rule(o->repo->index, attr_path);
3672         data.conflict_marker_size = ll_merge_marker_size(o->repo->index, attr_path);
3673
3674         if (fill_mmfile(o->repo, &mf1, one) < 0 ||
3675             fill_mmfile(o->repo, &mf2, two) < 0)
3676                 die("unable to read files to diff");
3677
3678         /*
3679          * All the other codepaths check both sides, but not checking
3680          * the "old" side here is deliberate.  We are checking the newly
3681          * introduced changes, and as long as the "new" side is text, we
3682          * can and should check what it introduces.
3683          */
3684         if (diff_filespec_is_binary(o->repo, two))
3685                 goto free_and_return;
3686         else {
3687                 /* Crazy xdl interfaces.. */
3688                 xpparam_t xpp;
3689                 xdemitconf_t xecfg;
3690
3691                 memset(&xpp, 0, sizeof(xpp));
3692                 memset(&xecfg, 0, sizeof(xecfg));
3693                 xecfg.ctxlen = 1; /* at least one context line */
3694                 xpp.flags = 0;
3695                 if (xdi_diff_outf(&mf1, &mf2, checkdiff_consume_hunk,
3696                                   checkdiff_consume, &data,
3697                                   &xpp, &xecfg))
3698                         die("unable to generate checkdiff for %s", one->path);
3699
3700                 if (data.ws_rule & WS_BLANK_AT_EOF) {
3701                         struct emit_callback ecbdata;
3702                         int blank_at_eof;
3703
3704                         ecbdata.ws_rule = data.ws_rule;
3705                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
3706                         blank_at_eof = ecbdata.blank_at_eof_in_postimage;
3707
3708                         if (blank_at_eof) {
3709                                 static char *err;
3710                                 if (!err)
3711                                         err = whitespace_error_string(WS_BLANK_AT_EOF);
3712                                 fprintf(o->file, "%s:%d: %s.\n",
3713                                         data.filename, blank_at_eof, err);
3714                                 data.status = 1; /* report errors */
3715                         }
3716                 }
3717         }
3718  free_and_return:
3719         diff_free_filespec_data(one);
3720         diff_free_filespec_data(two);
3721         if (data.status)
3722                 o->flags.check_failed = 1;
3723 }
3724
3725 struct diff_filespec *alloc_filespec(const char *path)
3726 {
3727         struct diff_filespec *spec;
3728
3729         FLEXPTR_ALLOC_STR(spec, path, path);
3730         spec->count = 1;
3731         spec->is_binary = -1;
3732         return spec;
3733 }
3734
3735 void free_filespec(struct diff_filespec *spec)
3736 {
3737         if (!--spec->count) {
3738                 diff_free_filespec_data(spec);
3739                 free(spec);
3740         }
3741 }
3742
3743 void fill_filespec(struct diff_filespec *spec, const struct object_id *oid,
3744                    int oid_valid, unsigned short mode)
3745 {
3746         if (mode) {
3747                 spec->mode = canon_mode(mode);
3748                 oidcpy(&spec->oid, oid);
3749                 spec->oid_valid = oid_valid;
3750         }
3751 }
3752
3753 /*
3754  * Given a name and sha1 pair, if the index tells us the file in
3755  * the work tree has that object contents, return true, so that
3756  * prepare_temp_file() does not have to inflate and extract.
3757  */
3758 static int reuse_worktree_file(struct index_state *istate,
3759                                const char *name,
3760                                const struct object_id *oid,
3761                                int want_file)
3762 {
3763         const struct cache_entry *ce;
3764         struct stat st;
3765         int pos, len;
3766
3767         /*
3768          * We do not read the cache ourselves here, because the
3769          * benchmark with my previous version that always reads cache
3770          * shows that it makes things worse for diff-tree comparing
3771          * two linux-2.6 kernel trees in an already checked out work
3772          * tree.  This is because most diff-tree comparisons deal with
3773          * only a small number of files, while reading the cache is
3774          * expensive for a large project, and its cost outweighs the
3775          * savings we get by not inflating the object to a temporary
3776          * file.  Practically, this code only helps when we are used
3777          * by diff-cache --cached, which does read the cache before
3778          * calling us.
3779          */
3780         if (!istate->cache)
3781                 return 0;
3782
3783         /* We want to avoid the working directory if our caller
3784          * doesn't need the data in a normal file, this system
3785          * is rather slow with its stat/open/mmap/close syscalls,
3786          * and the object is contained in a pack file.  The pack
3787          * is probably already open and will be faster to obtain
3788          * the data through than the working directory.  Loose
3789          * objects however would tend to be slower as they need
3790          * to be individually opened and inflated.
3791          */
3792         if (!FAST_WORKING_DIRECTORY && !want_file && has_object_pack(oid))
3793                 return 0;
3794
3795         /*
3796          * Similarly, if we'd have to convert the file contents anyway, that
3797          * makes the optimization not worthwhile.
3798          */
3799         if (!want_file && would_convert_to_git(istate, name))
3800                 return 0;
3801
3802         len = strlen(name);
3803         pos = index_name_pos(istate, name, len);
3804         if (pos < 0)
3805                 return 0;
3806         ce = istate->cache[pos];
3807
3808         /*
3809          * This is not the sha1 we are looking for, or
3810          * unreusable because it is not a regular file.
3811          */
3812         if (!oideq(oid, &ce->oid) || !S_ISREG(ce->ce_mode))
3813                 return 0;
3814
3815         /*
3816          * If ce is marked as "assume unchanged", there is no
3817          * guarantee that work tree matches what we are looking for.
3818          */
3819         if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
3820                 return 0;
3821
3822         /*
3823          * If ce matches the file in the work tree, we can reuse it.
3824          */
3825         if (ce_uptodate(ce) ||
3826             (!lstat(name, &st) && !ie_match_stat(istate, ce, &st, 0)))
3827                 return 1;
3828
3829         return 0;
3830 }
3831
3832 static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
3833 {
3834         struct strbuf buf = STRBUF_INIT;
3835         char *dirty = "";
3836
3837         /* Are we looking at the work tree? */
3838         if (s->dirty_submodule)
3839                 dirty = "-dirty";
3840
3841         strbuf_addf(&buf, "Subproject commit %s%s\n",
3842                     oid_to_hex(&s->oid), dirty);
3843         s->size = buf.len;
3844         if (size_only) {
3845                 s->data = NULL;
3846                 strbuf_release(&buf);
3847         } else {
3848                 s->data = strbuf_detach(&buf, NULL);
3849                 s->should_free = 1;
3850         }
3851         return 0;
3852 }
3853
3854 /*
3855  * While doing rename detection and pickaxe operation, we may need to
3856  * grab the data for the blob (or file) for our own in-core comparison.
3857  * diff_filespec has data and size fields for this purpose.
3858  */
3859 int diff_populate_filespec(struct repository *r,
3860                            struct diff_filespec *s,
3861                            unsigned int flags)
3862 {
3863         int size_only = flags & CHECK_SIZE_ONLY;
3864         int err = 0;
3865         int conv_flags = global_conv_flags_eol;
3866         /*
3867          * demote FAIL to WARN to allow inspecting the situation
3868          * instead of refusing.
3869          */
3870         if (conv_flags & CONV_EOL_RNDTRP_DIE)
3871                 conv_flags = CONV_EOL_RNDTRP_WARN;
3872
3873         if (!DIFF_FILE_VALID(s))
3874                 die("internal error: asking to populate invalid file.");
3875         if (S_ISDIR(s->mode))
3876                 return -1;
3877
3878         if (s->data)
3879                 return 0;
3880
3881         if (size_only && 0 < s->size)
3882                 return 0;
3883
3884         if (S_ISGITLINK(s->mode))
3885                 return diff_populate_gitlink(s, size_only);
3886
3887         if (!s->oid_valid ||
3888             reuse_worktree_file(r->index, s->path, &s->oid, 0)) {
3889                 struct strbuf buf = STRBUF_INIT;
3890                 struct stat st;
3891                 int fd;
3892
3893                 if (lstat(s->path, &st) < 0) {
3894                 err_empty:
3895                         err = -1;
3896                 empty:
3897                         s->data = (char *)"";
3898                         s->size = 0;
3899                         return err;
3900                 }
3901                 s->size = xsize_t(st.st_size);
3902                 if (!s->size)
3903                         goto empty;
3904                 if (S_ISLNK(st.st_mode)) {
3905                         struct strbuf sb = STRBUF_INIT;
3906
3907                         if (strbuf_readlink(&sb, s->path, s->size))
3908                                 goto err_empty;
3909                         s->size = sb.len;
3910                         s->data = strbuf_detach(&sb, NULL);
3911                         s->should_free = 1;
3912                         return 0;
3913                 }
3914
3915                 /*
3916                  * Even if the caller would be happy with getting
3917                  * only the size, we cannot return early at this
3918                  * point if the path requires us to run the content
3919                  * conversion.
3920                  */
3921                 if (size_only && !would_convert_to_git(r->index, s->path))
3922                         return 0;
3923
3924                 /*
3925                  * Note: this check uses xsize_t(st.st_size) that may
3926                  * not be the true size of the blob after it goes
3927                  * through convert_to_git().  This may not strictly be
3928                  * correct, but the whole point of big_file_threshold
3929                  * and is_binary check being that we want to avoid
3930                  * opening the file and inspecting the contents, this
3931                  * is probably fine.
3932                  */
3933                 if ((flags & CHECK_BINARY) &&
3934                     s->size > big_file_threshold && s->is_binary == -1) {
3935                         s->is_binary = 1;
3936                         return 0;
3937                 }
3938                 fd = open(s->path, O_RDONLY);
3939                 if (fd < 0)
3940                         goto err_empty;
3941                 s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
3942                 close(fd);
3943                 s->should_munmap = 1;
3944
3945                 /*
3946                  * Convert from working tree format to canonical git format
3947                  */
3948                 if (convert_to_git(r->index, s->path, s->data, s->size, &buf, conv_flags)) {
3949                         size_t size = 0;
3950                         munmap(s->data, s->size);
3951                         s->should_munmap = 0;
3952                         s->data = strbuf_detach(&buf, &size);
3953                         s->size = size;
3954                         s->should_free = 1;
3955                 }
3956         }
3957         else {
3958                 enum object_type type;
3959                 if (size_only || (flags & CHECK_BINARY)) {
3960                         type = oid_object_info(r, &s->oid, &s->size);
3961                         if (type < 0)
3962                                 die("unable to read %s",
3963                                     oid_to_hex(&s->oid));
3964                         if (size_only)
3965                                 return 0;
3966                         if (s->size > big_file_threshold && s->is_binary == -1) {
3967                                 s->is_binary = 1;
3968                                 return 0;
3969                         }
3970                 }
3971                 s->data = read_object_file(&s->oid, &type, &s->size);
3972                 if (!s->data)
3973                         die("unable to read %s", oid_to_hex(&s->oid));
3974                 s->should_free = 1;
3975         }
3976         return 0;
3977 }
3978
3979 void diff_free_filespec_blob(struct diff_filespec *s)
3980 {
3981         if (s->should_free)
3982                 free(s->data);
3983         else if (s->should_munmap)
3984                 munmap(s->data, s->size);
3985
3986         if (s->should_free || s->should_munmap) {
3987                 s->should_free = s->should_munmap = 0;
3988                 s->data = NULL;
3989         }
3990 }
3991
3992 void diff_free_filespec_data(struct diff_filespec *s)
3993 {
3994         diff_free_filespec_blob(s);
3995         FREE_AND_NULL(s->cnt_data);
3996 }
3997
3998 static void prep_temp_blob(struct index_state *istate,
3999                            const char *path, struct diff_tempfile *temp,
4000                            void *blob,
4001                            unsigned long size,
4002                            const struct object_id *oid,
4003                            int mode)
4004 {
4005         struct strbuf buf = STRBUF_INIT;
4006         struct strbuf tempfile = STRBUF_INIT;
4007         char *path_dup = xstrdup(path);
4008         const char *base = basename(path_dup);
4009
4010         /* Generate "XXXXXX_basename.ext" */
4011         strbuf_addstr(&tempfile, "XXXXXX_");
4012         strbuf_addstr(&tempfile, base);
4013
4014         temp->tempfile = mks_tempfile_ts(tempfile.buf, strlen(base) + 1);
4015         if (!temp->tempfile)
4016                 die_errno("unable to create temp-file");
4017         if (convert_to_working_tree(istate, path,
4018                         (const char *)blob, (size_t)size, &buf)) {
4019                 blob = buf.buf;
4020                 size = buf.len;
4021         }
4022         if (write_in_full(temp->tempfile->fd, blob, size) < 0 ||
4023             close_tempfile_gently(temp->tempfile))
4024                 die_errno("unable to write temp-file");
4025         temp->name = get_tempfile_path(temp->tempfile);
4026         oid_to_hex_r(temp->hex, oid);
4027         xsnprintf(temp->mode, sizeof(temp->mode), "%06o", mode);
4028         strbuf_release(&buf);
4029         strbuf_release(&tempfile);
4030         free(path_dup);
4031 }
4032
4033 static struct diff_tempfile *prepare_temp_file(struct repository *r,
4034                                                const char *name,
4035                                                struct diff_filespec *one)
4036 {
4037         struct diff_tempfile *temp = claim_diff_tempfile();
4038
4039         if (!DIFF_FILE_VALID(one)) {
4040         not_a_valid_file:
4041                 /* A '-' entry produces this for file-2, and
4042                  * a '+' entry produces this for file-1.
4043                  */
4044                 temp->name = "/dev/null";
4045                 xsnprintf(temp->hex, sizeof(temp->hex), ".");
4046                 xsnprintf(temp->mode, sizeof(temp->mode), ".");
4047                 return temp;
4048         }
4049
4050         if (!S_ISGITLINK(one->mode) &&
4051             (!one->oid_valid ||
4052              reuse_worktree_file(r->index, name, &one->oid, 1))) {
4053                 struct stat st;
4054                 if (lstat(name, &st) < 0) {
4055                         if (errno == ENOENT)
4056                                 goto not_a_valid_file;
4057                         die_errno("stat(%s)", name);
4058                 }
4059                 if (S_ISLNK(st.st_mode)) {
4060                         struct strbuf sb = STRBUF_INIT;
4061                         if (strbuf_readlink(&sb, name, st.st_size) < 0)
4062                                 die_errno("readlink(%s)", name);
4063                         prep_temp_blob(r->index, name, temp, sb.buf, sb.len,
4064                                        (one->oid_valid ?
4065                                         &one->oid : &null_oid),
4066                                        (one->oid_valid ?
4067                                         one->mode : S_IFLNK));
4068                         strbuf_release(&sb);
4069                 }
4070                 else {
4071                         /* we can borrow from the file in the work tree */
4072                         temp->name = name;
4073                         if (!one->oid_valid)
4074                                 oid_to_hex_r(temp->hex, &null_oid);
4075                         else
4076                                 oid_to_hex_r(temp->hex, &one->oid);
4077                         /* Even though we may sometimes borrow the
4078                          * contents from the work tree, we always want
4079                          * one->mode.  mode is trustworthy even when
4080                          * !(one->oid_valid), as long as
4081                          * DIFF_FILE_VALID(one).
4082                          */
4083                         xsnprintf(temp->mode, sizeof(temp->mode), "%06o", one->mode);
4084                 }
4085                 return temp;
4086         }
4087         else {
4088                 if (diff_populate_filespec(r, one, 0))
4089                         die("cannot read data blob for %s", one->path);
4090                 prep_temp_blob(r->index, name, temp,
4091                                one->data, one->size,
4092                                &one->oid, one->mode);
4093         }
4094         return temp;
4095 }
4096
4097 static void add_external_diff_name(struct repository *r,
4098                                    struct argv_array *argv,
4099                                    const char *name,
4100                                    struct diff_filespec *df)
4101 {
4102         struct diff_tempfile *temp = prepare_temp_file(r, name, df);
4103         argv_array_push(argv, temp->name);
4104         argv_array_push(argv, temp->hex);
4105         argv_array_push(argv, temp->mode);
4106 }
4107
4108 /* An external diff command takes:
4109  *
4110  * diff-cmd name infile1 infile1-sha1 infile1-mode \
4111  *               infile2 infile2-sha1 infile2-mode [ rename-to ]
4112  *
4113  */
4114 static void run_external_diff(const char *pgm,
4115                               const char *name,
4116                               const char *other,
4117                               struct diff_filespec *one,
4118                               struct diff_filespec *two,
4119                               const char *xfrm_msg,
4120                               int complete_rewrite,
4121                               struct diff_options *o)
4122 {
4123         struct argv_array argv = ARGV_ARRAY_INIT;
4124         struct argv_array env = ARGV_ARRAY_INIT;
4125         struct diff_queue_struct *q = &diff_queued_diff;
4126
4127         argv_array_push(&argv, pgm);
4128         argv_array_push(&argv, name);
4129
4130         if (one && two) {
4131                 add_external_diff_name(o->repo, &argv, name, one);
4132                 if (!other)
4133                         add_external_diff_name(o->repo, &argv, name, two);
4134                 else {
4135                         add_external_diff_name(o->repo, &argv, other, two);
4136                         argv_array_push(&argv, other);
4137                         argv_array_push(&argv, xfrm_msg);
4138                 }
4139         }
4140
4141         argv_array_pushf(&env, "GIT_DIFF_PATH_COUNTER=%d", ++o->diff_path_counter);
4142         argv_array_pushf(&env, "GIT_DIFF_PATH_TOTAL=%d", q->nr);
4143
4144         if (run_command_v_opt_cd_env(argv.argv, RUN_USING_SHELL, NULL, env.argv))
4145                 die(_("external diff died, stopping at %s"), name);
4146
4147         remove_tempfile();
4148         argv_array_clear(&argv);
4149         argv_array_clear(&env);
4150 }
4151
4152 static int similarity_index(struct diff_filepair *p)
4153 {
4154         return p->score * 100 / MAX_SCORE;
4155 }
4156
4157 static const char *diff_abbrev_oid(const struct object_id *oid, int abbrev)
4158 {
4159         if (startup_info->have_repository)
4160                 return find_unique_abbrev(oid, abbrev);
4161         else {
4162                 char *hex = oid_to_hex(oid);
4163                 if (abbrev < 0)
4164                         abbrev = FALLBACK_DEFAULT_ABBREV;
4165                 if (abbrev > the_hash_algo->hexsz)
4166                         BUG("oid abbreviation out of range: %d", abbrev);
4167                 if (abbrev)
4168                         hex[abbrev] = '\0';
4169                 return hex;
4170         }
4171 }
4172
4173 static void fill_metainfo(struct strbuf *msg,
4174                           const char *name,
4175                           const char *other,
4176                           struct diff_filespec *one,
4177                           struct diff_filespec *two,
4178                           struct diff_options *o,
4179                           struct diff_filepair *p,
4180                           int *must_show_header,
4181                           int use_color)
4182 {
4183         const char *set = diff_get_color(use_color, DIFF_METAINFO);
4184         const char *reset = diff_get_color(use_color, DIFF_RESET);
4185         const char *line_prefix = diff_line_prefix(o);
4186
4187         *must_show_header = 1;
4188         strbuf_init(msg, PATH_MAX * 2 + 300);
4189         switch (p->status) {
4190         case DIFF_STATUS_COPIED:
4191                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
4192                             line_prefix, set, similarity_index(p));
4193                 strbuf_addf(msg, "%s\n%s%scopy from ",
4194                             reset,  line_prefix, set);
4195                 quote_c_style(name, msg, NULL, 0);
4196                 strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
4197                 quote_c_style(other, msg, NULL, 0);
4198                 strbuf_addf(msg, "%s\n", reset);
4199                 break;
4200         case DIFF_STATUS_RENAMED:
4201                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
4202                             line_prefix, set, similarity_index(p));
4203                 strbuf_addf(msg, "%s\n%s%srename from ",
4204                             reset, line_prefix, set);
4205                 quote_c_style(name, msg, NULL, 0);
4206                 strbuf_addf(msg, "%s\n%s%srename to ",
4207                             reset, line_prefix, set);
4208                 quote_c_style(other, msg, NULL, 0);
4209                 strbuf_addf(msg, "%s\n", reset);
4210                 break;
4211         case DIFF_STATUS_MODIFIED:
4212                 if (p->score) {
4213                         strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
4214                                     line_prefix,
4215                                     set, similarity_index(p), reset);
4216                         break;
4217                 }
4218                 /* fallthru */
4219         default:
4220                 *must_show_header = 0;
4221         }
4222         if (one && two && !oideq(&one->oid, &two->oid)) {
4223                 const unsigned hexsz = the_hash_algo->hexsz;
4224                 int abbrev = o->flags.full_index ? hexsz : DEFAULT_ABBREV;
4225
4226                 if (o->flags.binary) {
4227                         mmfile_t mf;
4228                         if ((!fill_mmfile(o->repo, &mf, one) &&
4229                              diff_filespec_is_binary(o->repo, one)) ||
4230                             (!fill_mmfile(o->repo, &mf, two) &&
4231                              diff_filespec_is_binary(o->repo, two)))
4232                                 abbrev = hexsz;
4233                 }
4234                 strbuf_addf(msg, "%s%sindex %s..%s", line_prefix, set,
4235                             diff_abbrev_oid(&one->oid, abbrev),
4236                             diff_abbrev_oid(&two->oid, abbrev));
4237                 if (one->mode == two->mode)
4238                         strbuf_addf(msg, " %06o", one->mode);
4239                 strbuf_addf(msg, "%s\n", reset);
4240         }
4241 }
4242
4243 static void run_diff_cmd(const char *pgm,
4244                          const char *name,
4245                          const char *other,
4246                          const char *attr_path,
4247                          struct diff_filespec *one,
4248                          struct diff_filespec *two,
4249                          struct strbuf *msg,
4250                          struct diff_options *o,
4251                          struct diff_filepair *p)
4252 {
4253         const char *xfrm_msg = NULL;
4254         int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
4255         int must_show_header = 0;
4256
4257
4258         if (o->flags.allow_external) {
4259                 struct userdiff_driver *drv;
4260
4261                 drv = userdiff_find_by_path(o->repo->index, attr_path);
4262                 if (drv && drv->external)
4263                         pgm = drv->external;
4264         }
4265
4266         if (msg) {
4267                 /*
4268                  * don't use colors when the header is intended for an
4269                  * external diff driver
4270                  */
4271                 fill_metainfo(msg, name, other, one, two, o, p,
4272                               &must_show_header,
4273                               want_color(o->use_color) && !pgm);
4274                 xfrm_msg = msg->len ? msg->buf : NULL;
4275         }
4276
4277         if (pgm) {
4278                 run_external_diff(pgm, name, other, one, two, xfrm_msg,
4279                                   complete_rewrite, o);
4280                 return;
4281         }
4282         if (one && two)
4283                 builtin_diff(name, other ? other : name,
4284                              one, two, xfrm_msg, must_show_header,
4285                              o, complete_rewrite);
4286         else
4287                 fprintf(o->file, "* Unmerged path %s\n", name);
4288 }
4289
4290 static void diff_fill_oid_info(struct diff_filespec *one, struct index_state *istate)
4291 {
4292         if (DIFF_FILE_VALID(one)) {
4293                 if (!one->oid_valid) {
4294                         struct stat st;
4295                         if (one->is_stdin) {
4296                                 oidclr(&one->oid);
4297                                 return;
4298                         }
4299                         if (lstat(one->path, &st) < 0)
4300                                 die_errno("stat '%s'", one->path);
4301                         if (index_path(istate, &one->oid, one->path, &st, 0))
4302                                 die("cannot hash %s", one->path);
4303                 }
4304         }
4305         else
4306                 oidclr(&one->oid);
4307 }
4308
4309 static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
4310 {
4311         /* Strip the prefix but do not molest /dev/null and absolute paths */
4312         if (*namep && !is_absolute_path(*namep)) {
4313                 *namep += prefix_length;
4314                 if (**namep == '/')
4315                         ++*namep;
4316         }
4317         if (*otherp && !is_absolute_path(*otherp)) {
4318                 *otherp += prefix_length;
4319                 if (**otherp == '/')
4320                         ++*otherp;
4321         }
4322 }
4323
4324 static void run_diff(struct diff_filepair *p, struct diff_options *o)
4325 {
4326         const char *pgm = external_diff();
4327         struct strbuf msg;
4328         struct diff_filespec *one = p->one;
4329         struct diff_filespec *two = p->two;
4330         const char *name;
4331         const char *other;
4332         const char *attr_path;
4333
4334         name  = one->path;
4335         other = (strcmp(name, two->path) ? two->path : NULL);
4336         attr_path = name;
4337         if (o->prefix_length)
4338                 strip_prefix(o->prefix_length, &name, &other);
4339
4340         if (!o->flags.allow_external)
4341                 pgm = NULL;
4342
4343         if (DIFF_PAIR_UNMERGED(p)) {
4344                 run_diff_cmd(pgm, name, NULL, attr_path,
4345                              NULL, NULL, NULL, o, p);
4346                 return;
4347         }
4348
4349         diff_fill_oid_info(one, o->repo->index);
4350         diff_fill_oid_info(two, o->repo->index);
4351
4352         if (!pgm &&
4353             DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
4354             (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
4355                 /*
4356                  * a filepair that changes between file and symlink
4357                  * needs to be split into deletion and creation.
4358                  */
4359                 struct diff_filespec *null = alloc_filespec(two->path);
4360                 run_diff_cmd(NULL, name, other, attr_path,
4361                              one, null, &msg,
4362                              o, p);
4363                 free(null);
4364                 strbuf_release(&msg);
4365
4366                 null = alloc_filespec(one->path);
4367                 run_diff_cmd(NULL, name, other, attr_path,
4368                              null, two, &msg, o, p);
4369                 free(null);
4370         }
4371         else
4372                 run_diff_cmd(pgm, name, other, attr_path,
4373                              one, two, &msg, o, p);
4374
4375         strbuf_release(&msg);
4376 }
4377
4378 static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
4379                          struct diffstat_t *diffstat)
4380 {
4381         const char *name;
4382         const char *other;
4383
4384         if (DIFF_PAIR_UNMERGED(p)) {
4385                 /* unmerged */
4386                 builtin_diffstat(p->one->path, NULL, NULL, NULL,
4387                                  diffstat, o, p);
4388                 return;
4389         }
4390
4391         name = p->one->path;
4392         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
4393
4394         if (o->prefix_length)
4395                 strip_prefix(o->prefix_length, &name, &other);
4396
4397         diff_fill_oid_info(p->one, o->repo->index);
4398         diff_fill_oid_info(p->two, o->repo->index);
4399
4400         builtin_diffstat(name, other, p->one, p->two,
4401                          diffstat, o, p);
4402 }
4403
4404 static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
4405 {
4406         const char *name;
4407         const char *other;
4408         const char *attr_path;
4409
4410         if (DIFF_PAIR_UNMERGED(p)) {
4411                 /* unmerged */
4412                 return;
4413         }
4414
4415         name = p->one->path;
4416         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
4417         attr_path = other ? other : name;
4418
4419         if (o->prefix_length)
4420                 strip_prefix(o->prefix_length, &name, &other);
4421
4422         diff_fill_oid_info(p->one, o->repo->index);
4423         diff_fill_oid_info(p->two, o->repo->index);
4424
4425         builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
4426 }
4427
4428 void repo_diff_setup(struct repository *r, struct diff_options *options)
4429 {
4430         memcpy(options, &default_diff_options, sizeof(*options));
4431
4432         options->file = stdout;
4433         options->repo = r;
4434
4435         options->output_indicators[OUTPUT_INDICATOR_NEW] = '+';
4436         options->output_indicators[OUTPUT_INDICATOR_OLD] = '-';
4437         options->output_indicators[OUTPUT_INDICATOR_CONTEXT] = ' ';
4438         options->abbrev = DEFAULT_ABBREV;
4439         options->line_termination = '\n';
4440         options->break_opt = -1;
4441         options->rename_limit = -1;
4442         options->dirstat_permille = diff_dirstat_permille_default;
4443         options->context = diff_context_default;
4444         options->interhunkcontext = diff_interhunk_context_default;
4445         options->ws_error_highlight = ws_error_highlight_default;
4446         options->flags.rename_empty = 1;
4447         options->objfind = NULL;
4448
4449         /* pathchange left =NULL by default */
4450         options->change = diff_change;
4451         options->add_remove = diff_addremove;
4452         options->use_color = diff_use_color_default;
4453         options->detect_rename = diff_detect_rename_default;
4454         options->xdl_opts |= diff_algorithm;
4455         if (diff_indent_heuristic)
4456                 DIFF_XDL_SET(options, INDENT_HEURISTIC);
4457
4458         options->orderfile = diff_order_file_cfg;
4459
4460         if (diff_no_prefix) {
4461                 options->a_prefix = options->b_prefix = "";
4462         } else if (!diff_mnemonic_prefix) {
4463                 options->a_prefix = "a/";
4464                 options->b_prefix = "b/";
4465         }
4466
4467         options->color_moved = diff_color_moved_default;
4468         options->color_moved_ws_handling = diff_color_moved_ws_default;
4469 }
4470
4471 void diff_setup_done(struct diff_options *options)
4472 {
4473         unsigned check_mask = DIFF_FORMAT_NAME |
4474                               DIFF_FORMAT_NAME_STATUS |
4475                               DIFF_FORMAT_CHECKDIFF |
4476                               DIFF_FORMAT_NO_OUTPUT;
4477         /*
4478          * This must be signed because we're comparing against a potentially
4479          * negative value.
4480          */
4481         const int hexsz = the_hash_algo->hexsz;
4482
4483         if (options->set_default)
4484                 options->set_default(options);
4485
4486         if (HAS_MULTI_BITS(options->output_format & check_mask))
4487                 die(_("--name-only, --name-status, --check and -s are mutually exclusive"));
4488
4489         if (HAS_MULTI_BITS(options->pickaxe_opts & DIFF_PICKAXE_KINDS_MASK))
4490                 die(_("-G, -S and --find-object are mutually exclusive"));
4491
4492         /*
4493          * Most of the time we can say "there are changes"
4494          * only by checking if there are changed paths, but
4495          * --ignore-whitespace* options force us to look
4496          * inside contents.
4497          */
4498
4499         if ((options->xdl_opts & XDF_WHITESPACE_FLAGS))
4500                 options->flags.diff_from_contents = 1;
4501         else
4502                 options->flags.diff_from_contents = 0;
4503
4504         if (options->flags.find_copies_harder)
4505                 options->detect_rename = DIFF_DETECT_COPY;
4506
4507         if (!options->flags.relative_name)
4508                 options->prefix = NULL;
4509         if (options->prefix)
4510                 options->prefix_length = strlen(options->prefix);
4511         else
4512                 options->prefix_length = 0;
4513
4514         if (options->output_format & (DIFF_FORMAT_NAME |
4515                                       DIFF_FORMAT_NAME_STATUS |
4516                                       DIFF_FORMAT_CHECKDIFF |
4517                                       DIFF_FORMAT_NO_OUTPUT))
4518                 options->output_format &= ~(DIFF_FORMAT_RAW |
4519                                             DIFF_FORMAT_NUMSTAT |
4520                                             DIFF_FORMAT_DIFFSTAT |
4521                                             DIFF_FORMAT_SHORTSTAT |
4522                                             DIFF_FORMAT_DIRSTAT |
4523                                             DIFF_FORMAT_SUMMARY |
4524                                             DIFF_FORMAT_PATCH);
4525
4526         /*
4527          * These cases always need recursive; we do not drop caller-supplied
4528          * recursive bits for other formats here.
4529          */
4530         if (options->output_format & (DIFF_FORMAT_PATCH |
4531                                       DIFF_FORMAT_NUMSTAT |
4532                                       DIFF_FORMAT_DIFFSTAT |
4533                                       DIFF_FORMAT_SHORTSTAT |
4534                                       DIFF_FORMAT_DIRSTAT |
4535                                       DIFF_FORMAT_SUMMARY |
4536                                       DIFF_FORMAT_CHECKDIFF))
4537                 options->flags.recursive = 1;
4538         /*
4539          * Also pickaxe would not work very well if you do not say recursive
4540          */
4541         if (options->pickaxe_opts & DIFF_PICKAXE_KINDS_MASK)
4542                 options->flags.recursive = 1;
4543         /*
4544          * When patches are generated, submodules diffed against the work tree
4545          * must be checked for dirtiness too so it can be shown in the output
4546          */
4547         if (options->output_format & DIFF_FORMAT_PATCH)
4548                 options->flags.dirty_submodules = 1;
4549
4550         if (options->detect_rename && options->rename_limit < 0)
4551                 options->rename_limit = diff_rename_limit_default;
4552         if (hexsz < options->abbrev)
4553                 options->abbrev = hexsz; /* full */
4554
4555         /*
4556          * It does not make sense to show the first hit we happened
4557          * to have found.  It does not make sense not to return with
4558          * exit code in such a case either.
4559          */
4560         if (options->flags.quick) {
4561                 options->output_format = DIFF_FORMAT_NO_OUTPUT;
4562                 options->flags.exit_with_status = 1;
4563         }
4564
4565         options->diff_path_counter = 0;
4566
4567         if (options->flags.follow_renames && options->pathspec.nr != 1)
4568                 die(_("--follow requires exactly one pathspec"));
4569
4570         if (!options->use_color || external_diff())
4571                 options->color_moved = 0;
4572 }
4573
4574 static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
4575 {
4576         char c, *eq;
4577         int len;
4578
4579         if (*arg != '-')
4580                 return 0;
4581         c = *++arg;
4582         if (!c)
4583                 return 0;
4584         if (c == arg_short) {
4585                 c = *++arg;
4586                 if (!c)
4587                         return 1;
4588                 if (val && isdigit(c)) {
4589                         char *end;
4590                         int n = strtoul(arg, &end, 10);
4591                         if (*end)
4592                                 return 0;
4593                         *val = n;
4594                         return 1;
4595                 }
4596                 return 0;
4597         }
4598         if (c != '-')
4599                 return 0;
4600         arg++;
4601         eq = strchrnul(arg, '=');
4602         len = eq - arg;
4603         if (!len || strncmp(arg, arg_long, len))
4604                 return 0;
4605         if (*eq) {
4606                 int n;
4607                 char *end;
4608                 if (!isdigit(*++eq))
4609                         return 0;
4610                 n = strtoul(eq, &end, 10);
4611                 if (*end)
4612                         return 0;
4613                 *val = n;
4614         }
4615         return 1;
4616 }
4617
4618 static int diff_scoreopt_parse(const char *opt);
4619
4620 static inline int short_opt(char opt, const char **argv,
4621                             const char **optarg)
4622 {
4623         const char *arg = argv[0];
4624         if (arg[0] != '-' || arg[1] != opt)
4625                 return 0;
4626         if (arg[2] != '\0') {
4627                 *optarg = arg + 2;
4628                 return 1;
4629         }
4630         if (!argv[1])
4631                 die("Option '%c' requires a value", opt);
4632         *optarg = argv[1];
4633         return 2;
4634 }
4635
4636 int parse_long_opt(const char *opt, const char **argv,
4637                    const char **optarg)
4638 {
4639         const char *arg = argv[0];
4640         if (!skip_prefix(arg, "--", &arg))
4641                 return 0;
4642         if (!skip_prefix(arg, opt, &arg))
4643                 return 0;
4644         if (*arg == '=') { /* stuck form: --option=value */
4645                 *optarg = arg + 1;
4646                 return 1;
4647         }
4648         if (*arg != '\0')
4649                 return 0;
4650         /* separate form: --option value */
4651         if (!argv[1])
4652                 die("Option '--%s' requires a value", opt);
4653         *optarg = argv[1];
4654         return 2;
4655 }
4656
4657 static int stat_opt(struct diff_options *options, const char **av)
4658 {
4659         const char *arg = av[0];
4660         char *end;
4661         int width = options->stat_width;
4662         int name_width = options->stat_name_width;
4663         int graph_width = options->stat_graph_width;
4664         int count = options->stat_count;
4665         int argcount = 1;
4666
4667         if (!skip_prefix(arg, "--stat", &arg))
4668                 BUG("stat option does not begin with --stat: %s", arg);
4669         end = (char *)arg;
4670
4671         switch (*arg) {
4672         case '-':
4673                 if (skip_prefix(arg, "-width", &arg)) {
4674                         if (*arg == '=')
4675                                 width = strtoul(arg + 1, &end, 10);
4676                         else if (!*arg && !av[1])
4677                                 die_want_option("--stat-width");
4678                         else if (!*arg) {
4679                                 width = strtoul(av[1], &end, 10);
4680                                 argcount = 2;
4681                         }
4682                 } else if (skip_prefix(arg, "-name-width", &arg)) {
4683                         if (*arg == '=')
4684                                 name_width = strtoul(arg + 1, &end, 10);
4685                         else if (!*arg && !av[1])
4686                                 die_want_option("--stat-name-width");
4687                         else if (!*arg) {
4688                                 name_width = strtoul(av[1], &end, 10);
4689                                 argcount = 2;
4690                         }
4691                 } else if (skip_prefix(arg, "-graph-width", &arg)) {
4692                         if (*arg == '=')
4693                                 graph_width = strtoul(arg + 1, &end, 10);
4694                         else if (!*arg && !av[1])
4695                                 die_want_option("--stat-graph-width");
4696                         else if (!*arg) {
4697                                 graph_width = strtoul(av[1], &end, 10);
4698                                 argcount = 2;
4699                         }
4700                 } else if (skip_prefix(arg, "-count", &arg)) {
4701                         if (*arg == '=')
4702                                 count = strtoul(arg + 1, &end, 10);
4703                         else if (!*arg && !av[1])
4704                                 die_want_option("--stat-count");
4705                         else if (!*arg) {
4706                                 count = strtoul(av[1], &end, 10);
4707                                 argcount = 2;
4708                         }
4709                 }
4710                 break;
4711         case '=':
4712                 width = strtoul(arg+1, &end, 10);
4713                 if (*end == ',')
4714                         name_width = strtoul(end+1, &end, 10);
4715                 if (*end == ',')
4716                         count = strtoul(end+1, &end, 10);
4717         }
4718
4719         /* Important! This checks all the error cases! */
4720         if (*end)
4721                 return 0;
4722         options->output_format |= DIFF_FORMAT_DIFFSTAT;
4723         options->stat_name_width = name_width;
4724         options->stat_graph_width = graph_width;
4725         options->stat_width = width;
4726         options->stat_count = count;
4727         return argcount;
4728 }
4729
4730 static int parse_dirstat_opt(struct diff_options *options, const char *params)
4731 {
4732         struct strbuf errmsg = STRBUF_INIT;
4733         if (parse_dirstat_params(options, params, &errmsg))
4734                 die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
4735                     errmsg.buf);
4736         strbuf_release(&errmsg);
4737         /*
4738          * The caller knows a dirstat-related option is given from the command
4739          * line; allow it to say "return this_function();"
4740          */
4741         options->output_format |= DIFF_FORMAT_DIRSTAT;
4742         return 1;
4743 }
4744
4745 static int parse_submodule_opt(struct diff_options *options, const char *value)
4746 {
4747         if (parse_submodule_params(options, value))
4748                 die(_("Failed to parse --submodule option parameter: '%s'"),
4749                         value);
4750         return 1;
4751 }
4752
4753 static const char diff_status_letters[] = {
4754         DIFF_STATUS_ADDED,
4755         DIFF_STATUS_COPIED,
4756         DIFF_STATUS_DELETED,
4757         DIFF_STATUS_MODIFIED,
4758         DIFF_STATUS_RENAMED,
4759         DIFF_STATUS_TYPE_CHANGED,
4760         DIFF_STATUS_UNKNOWN,
4761         DIFF_STATUS_UNMERGED,
4762         DIFF_STATUS_FILTER_AON,
4763         DIFF_STATUS_FILTER_BROKEN,
4764         '\0',
4765 };
4766
4767 static unsigned int filter_bit['Z' + 1];
4768
4769 static void prepare_filter_bits(void)
4770 {
4771         int i;
4772
4773         if (!filter_bit[DIFF_STATUS_ADDED]) {
4774                 for (i = 0; diff_status_letters[i]; i++)
4775                         filter_bit[(int) diff_status_letters[i]] = (1 << i);
4776         }
4777 }
4778
4779 static unsigned filter_bit_tst(char status, const struct diff_options *opt)
4780 {
4781         return opt->filter & filter_bit[(int) status];
4782 }
4783
4784 static int parse_diff_filter_opt(const char *optarg, struct diff_options *opt)
4785 {
4786         int i, optch;
4787
4788         prepare_filter_bits();
4789
4790         /*
4791          * If there is a negation e.g. 'd' in the input, and we haven't
4792          * initialized the filter field with another --diff-filter, start
4793          * from full set of bits, except for AON.
4794          */
4795         if (!opt->filter) {
4796                 for (i = 0; (optch = optarg[i]) != '\0'; i++) {
4797                         if (optch < 'a' || 'z' < optch)
4798                                 continue;
4799                         opt->filter = (1 << (ARRAY_SIZE(diff_status_letters) - 1)) - 1;
4800                         opt->filter &= ~filter_bit[DIFF_STATUS_FILTER_AON];
4801                         break;
4802                 }
4803         }
4804
4805         for (i = 0; (optch = optarg[i]) != '\0'; i++) {
4806                 unsigned int bit;
4807                 int negate;
4808
4809                 if ('a' <= optch && optch <= 'z') {
4810                         negate = 1;
4811                         optch = toupper(optch);
4812                 } else {
4813                         negate = 0;
4814                 }
4815
4816                 bit = (0 <= optch && optch <= 'Z') ? filter_bit[optch] : 0;
4817                 if (!bit)
4818                         return optarg[i];
4819                 if (negate)
4820                         opt->filter &= ~bit;
4821                 else
4822                         opt->filter |= bit;
4823         }
4824         return 0;
4825 }
4826
4827 static void enable_patch_output(int *fmt) {
4828         *fmt &= ~DIFF_FORMAT_NO_OUTPUT;
4829         *fmt |= DIFF_FORMAT_PATCH;
4830 }
4831
4832 static int parse_ws_error_highlight_opt(struct diff_options *opt, const char *arg)
4833 {
4834         int val = parse_ws_error_highlight(arg);
4835
4836         if (val < 0) {
4837                 error("unknown value after ws-error-highlight=%.*s",
4838                       -1 - val, arg);
4839                 return 0;
4840         }
4841         opt->ws_error_highlight = val;
4842         return 1;
4843 }
4844
4845 static int parse_objfind_opt(struct diff_options *opt, const char *arg)
4846 {
4847         struct object_id oid;
4848
4849         if (get_oid(arg, &oid))
4850                 return error("unable to resolve '%s'", arg);
4851
4852         if (!opt->objfind)
4853                 opt->objfind = xcalloc(1, sizeof(*opt->objfind));
4854
4855         opt->pickaxe_opts |= DIFF_PICKAXE_KIND_OBJFIND;
4856         opt->flags.recursive = 1;
4857         opt->flags.tree_in_recursive = 1;
4858         oidset_insert(opt->objfind, &oid);
4859         return 1;
4860 }
4861
4862 int diff_opt_parse(struct diff_options *options,
4863                    const char **av, int ac, const char *prefix)
4864 {
4865         const char *arg = av[0];
4866         const char *optarg;
4867         int argcount;
4868
4869         if (!prefix)
4870                 prefix = "";
4871
4872         /* Output format options */
4873         if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch")
4874             || opt_arg(arg, 'U', "unified", &options->context))
4875                 enable_patch_output(&options->output_format);
4876         else if (!strcmp(arg, "--raw"))
4877                 options->output_format |= DIFF_FORMAT_RAW;
4878         else if (!strcmp(arg, "--patch-with-raw")) {
4879                 enable_patch_output(&options->output_format);
4880                 options->output_format |= DIFF_FORMAT_RAW;
4881         } else if (!strcmp(arg, "--numstat"))
4882                 options->output_format |= DIFF_FORMAT_NUMSTAT;
4883         else if (!strcmp(arg, "--shortstat"))
4884                 options->output_format |= DIFF_FORMAT_SHORTSTAT;
4885         else if (skip_prefix(arg, "-X", &arg) ||
4886                  skip_to_optional_arg(arg, "--dirstat", &arg))
4887                 return parse_dirstat_opt(options, arg);
4888         else if (!strcmp(arg, "--cumulative"))
4889                 return parse_dirstat_opt(options, "cumulative");
4890         else if (skip_to_optional_arg(arg, "--dirstat-by-file", &arg)) {
4891                 parse_dirstat_opt(options, "files");
4892                 return parse_dirstat_opt(options, arg);
4893         }
4894         else if (!strcmp(arg, "--check"))
4895                 options->output_format |= DIFF_FORMAT_CHECKDIFF;
4896         else if (!strcmp(arg, "--summary"))
4897                 options->output_format |= DIFF_FORMAT_SUMMARY;
4898         else if (!strcmp(arg, "--patch-with-stat")) {
4899                 enable_patch_output(&options->output_format);
4900                 options->output_format |= DIFF_FORMAT_DIFFSTAT;
4901         } else if (!strcmp(arg, "--name-only"))
4902                 options->output_format |= DIFF_FORMAT_NAME;
4903         else if (!strcmp(arg, "--name-status"))
4904                 options->output_format |= DIFF_FORMAT_NAME_STATUS;
4905         else if (!strcmp(arg, "-s") || !strcmp(arg, "--no-patch"))
4906                 options->output_format |= DIFF_FORMAT_NO_OUTPUT;
4907         else if (starts_with(arg, "--stat"))
4908                 /* --stat, --stat-width, --stat-name-width, or --stat-count */
4909                 return stat_opt(options, av);
4910         else if (!strcmp(arg, "--compact-summary")) {
4911                  options->flags.stat_with_summary = 1;
4912                  options->output_format |= DIFF_FORMAT_DIFFSTAT;
4913         } else if (!strcmp(arg, "--no-compact-summary"))
4914                  options->flags.stat_with_summary = 0;
4915         else if (skip_prefix(arg, "--output-indicator-new=", &arg))
4916                 options->output_indicators[OUTPUT_INDICATOR_NEW] = arg[0];
4917         else if (skip_prefix(arg, "--output-indicator-old=", &arg))
4918                 options->output_indicators[OUTPUT_INDICATOR_OLD] = arg[0];
4919         else if (skip_prefix(arg, "--output-indicator-context=", &arg))
4920                 options->output_indicators[OUTPUT_INDICATOR_CONTEXT] = arg[0];
4921
4922         /* renames options */
4923         else if (starts_with(arg, "-B") ||
4924                  skip_to_optional_arg(arg, "--break-rewrites", NULL)) {
4925                 if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
4926                         return error("invalid argument to -B: %s", arg+2);
4927         }
4928         else if (starts_with(arg, "-M") ||
4929                  skip_to_optional_arg(arg, "--find-renames", NULL)) {
4930                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
4931                         return error("invalid argument to -M: %s", arg+2);
4932                 options->detect_rename = DIFF_DETECT_RENAME;
4933         }
4934         else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
4935                 options->irreversible_delete = 1;
4936         }
4937         else if (starts_with(arg, "-C") ||
4938                  skip_to_optional_arg(arg, "--find-copies", NULL)) {
4939                 if (options->detect_rename == DIFF_DETECT_COPY)
4940                         options->flags.find_copies_harder = 1;
4941                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
4942                         return error("invalid argument to -C: %s", arg+2);
4943                 options->detect_rename = DIFF_DETECT_COPY;
4944         }
4945         else if (!strcmp(arg, "--no-renames"))
4946                 options->detect_rename = 0;
4947         else if (!strcmp(arg, "--rename-empty"))
4948                 options->flags.rename_empty = 1;
4949         else if (!strcmp(arg, "--no-rename-empty"))
4950                 options->flags.rename_empty = 0;
4951         else if (skip_to_optional_arg_default(arg, "--relative", &arg, NULL)) {
4952                 options->flags.relative_name = 1;
4953                 if (arg)
4954                         options->prefix = arg;
4955         }
4956
4957         /* xdiff options */
4958         else if (!strcmp(arg, "--minimal"))
4959                 DIFF_XDL_SET(options, NEED_MINIMAL);
4960         else if (!strcmp(arg, "--no-minimal"))
4961                 DIFF_XDL_CLR(options, NEED_MINIMAL);
4962         else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
4963                 DIFF_XDL_SET(options, IGNORE_WHITESPACE);
4964         else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
4965                 DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
4966         else if (!strcmp(arg, "--ignore-space-at-eol"))
4967                 DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
4968         else if (!strcmp(arg, "--ignore-cr-at-eol"))
4969                 DIFF_XDL_SET(options, IGNORE_CR_AT_EOL);
4970         else if (!strcmp(arg, "--ignore-blank-lines"))
4971                 DIFF_XDL_SET(options, IGNORE_BLANK_LINES);
4972         else if (!strcmp(arg, "--indent-heuristic"))
4973                 DIFF_XDL_SET(options, INDENT_HEURISTIC);
4974         else if (!strcmp(arg, "--no-indent-heuristic"))
4975                 DIFF_XDL_CLR(options, INDENT_HEURISTIC);
4976         else if (!strcmp(arg, "--patience")) {
4977                 int i;
4978                 options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
4979                 /*
4980                  * Both --patience and --anchored use PATIENCE_DIFF
4981                  * internally, so remove any anchors previously
4982                  * specified.
4983                  */
4984                 for (i = 0; i < options->anchors_nr; i++)
4985                         free(options->anchors[i]);
4986                 options->anchors_nr = 0;
4987         } else if (!strcmp(arg, "--histogram"))
4988                 options->xdl_opts = DIFF_WITH_ALG(options, HISTOGRAM_DIFF);
4989         else if ((argcount = parse_long_opt("diff-algorithm", av, &optarg))) {
4990                 long value = parse_algorithm_value(optarg);
4991                 if (value < 0)
4992                         return error("option diff-algorithm accepts \"myers\", "
4993                                      "\"minimal\", \"patience\" and \"histogram\"");
4994                 /* clear out previous settings */
4995                 DIFF_XDL_CLR(options, NEED_MINIMAL);
4996                 options->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
4997                 options->xdl_opts |= value;
4998                 return argcount;
4999         } else if (skip_prefix(arg, "--anchored=", &arg)) {
5000                 options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
5001                 ALLOC_GROW(options->anchors, options->anchors_nr + 1,
5002                            options->anchors_alloc);
5003                 options->anchors[options->anchors_nr++] = xstrdup(arg);
5004         }
5005
5006         /* flags options */
5007         else if (!strcmp(arg, "--binary")) {
5008                 enable_patch_output(&options->output_format);
5009                 options->flags.binary = 1;
5010         }
5011         else if (!strcmp(arg, "--full-index"))
5012                 options->flags.full_index = 1;
5013         else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
5014                 options->flags.text = 1;
5015         else if (!strcmp(arg, "-R"))
5016                 options->flags.reverse_diff = 1;
5017         else if (!strcmp(arg, "--find-copies-harder"))
5018                 options->flags.find_copies_harder = 1;
5019         else if (!strcmp(arg, "--follow"))
5020                 options->flags.follow_renames = 1;
5021         else if (!strcmp(arg, "--no-follow")) {
5022                 options->flags.follow_renames = 0;
5023                 options->flags.default_follow_renames = 0;
5024         } else if (skip_to_optional_arg_default(arg, "--color", &arg, "always")) {
5025                 int value = git_config_colorbool(NULL, arg);
5026                 if (value < 0)
5027                         return error("option `color' expects \"always\", \"auto\", or \"never\"");
5028                 options->use_color = value;
5029         }
5030         else if (!strcmp(arg, "--no-color"))
5031                 options->use_color = 0;
5032         else if (!strcmp(arg, "--color-moved")) {
5033                 if (diff_color_moved_default)
5034                         options->color_moved = diff_color_moved_default;
5035                 if (options->color_moved == COLOR_MOVED_NO)
5036                         options->color_moved = COLOR_MOVED_DEFAULT;
5037         } else if (!strcmp(arg, "--no-color-moved"))
5038                 options->color_moved = COLOR_MOVED_NO;
5039         else if (skip_prefix(arg, "--color-moved=", &arg)) {
5040                 int cm = parse_color_moved(arg);
5041                 if (cm < 0)
5042                         die("bad --color-moved argument: %s", arg);
5043                 options->color_moved = cm;
5044         } else if (!strcmp(arg, "--no-color-moved-ws")) {
5045                 options->color_moved_ws_handling = 0;
5046         } else if (skip_prefix(arg, "--color-moved-ws=", &arg)) {
5047                 options->color_moved_ws_handling = parse_color_moved_ws(arg);
5048         } else if (skip_to_optional_arg_default(arg, "--color-words", &options->word_regex, NULL)) {
5049                 options->use_color = 1;
5050                 options->word_diff = DIFF_WORDS_COLOR;
5051         }
5052         else if (!strcmp(arg, "--word-diff")) {
5053                 if (options->word_diff == DIFF_WORDS_NONE)
5054                         options->word_diff = DIFF_WORDS_PLAIN;
5055         }
5056         else if (skip_prefix(arg, "--word-diff=", &arg)) {
5057                 if (!strcmp(arg, "plain"))
5058                         options->word_diff = DIFF_WORDS_PLAIN;
5059                 else if (!strcmp(arg, "color")) {
5060                         options->use_color = 1;
5061                         options->word_diff = DIFF_WORDS_COLOR;
5062                 }
5063                 else if (!strcmp(arg, "porcelain"))
5064                         options->word_diff = DIFF_WORDS_PORCELAIN;
5065                 else if (!strcmp(arg, "none"))
5066                         options->word_diff = DIFF_WORDS_NONE;
5067                 else
5068                         die("bad --word-diff argument: %s", arg);
5069         }
5070         else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
5071                 if (options->word_diff == DIFF_WORDS_NONE)
5072                         options->word_diff = DIFF_WORDS_PLAIN;
5073                 options->word_regex = optarg;
5074                 return argcount;
5075         }
5076         else if (!strcmp(arg, "--exit-code"))
5077                 options->flags.exit_with_status = 1;
5078         else if (!strcmp(arg, "--quiet"))
5079                 options->flags.quick = 1;
5080         else if (!strcmp(arg, "--ext-diff"))
5081                 options->flags.allow_external = 1;
5082         else if (!strcmp(arg, "--no-ext-diff"))
5083                 options->flags.allow_external = 0;
5084         else if (!strcmp(arg, "--textconv")) {
5085                 options->flags.allow_textconv = 1;
5086                 options->flags.textconv_set_via_cmdline = 1;
5087         } else if (!strcmp(arg, "--no-textconv"))
5088                 options->flags.allow_textconv = 0;
5089         else if (skip_to_optional_arg_default(arg, "--ignore-submodules", &arg, "all")) {
5090                 options->flags.override_submodule_config = 1;
5091                 handle_ignore_submodules_arg(options, arg);
5092         } else if (skip_to_optional_arg_default(arg, "--submodule", &arg, "log"))
5093                 return parse_submodule_opt(options, arg);
5094         else if (skip_prefix(arg, "--ws-error-highlight=", &arg))
5095                 return parse_ws_error_highlight_opt(options, arg);
5096         else if (!strcmp(arg, "--ita-invisible-in-index"))
5097                 options->ita_invisible_in_index = 1;
5098         else if (!strcmp(arg, "--ita-visible-in-index"))
5099                 options->ita_invisible_in_index = 0;
5100
5101         /* misc options */
5102         else if (!strcmp(arg, "-z"))
5103                 options->line_termination = 0;
5104         else if ((argcount = short_opt('l', av, &optarg))) {
5105                 options->rename_limit = strtoul(optarg, NULL, 10);
5106                 return argcount;
5107         }
5108         else if ((argcount = short_opt('S', av, &optarg))) {
5109                 options->pickaxe = optarg;
5110                 options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
5111                 return argcount;
5112         } else if ((argcount = short_opt('G', av, &optarg))) {
5113                 options->pickaxe = optarg;
5114                 options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
5115                 return argcount;
5116         }
5117         else if (!strcmp(arg, "--pickaxe-all"))
5118                 options->pickaxe_opts |= DIFF_PICKAXE_ALL;
5119         else if (!strcmp(arg, "--pickaxe-regex"))
5120                 options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
5121         else if ((argcount = short_opt('O', av, &optarg))) {
5122                 options->orderfile = prefix_filename(prefix, optarg);
5123                 return argcount;
5124         } else if (skip_prefix(arg, "--find-object=", &arg))
5125                 return parse_objfind_opt(options, arg);
5126         else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
5127                 int offending = parse_diff_filter_opt(optarg, options);
5128                 if (offending)
5129                         die("unknown change class '%c' in --diff-filter=%s",
5130                             offending, optarg);
5131                 return argcount;
5132         }
5133         else if (!strcmp(arg, "--no-abbrev"))
5134                 options->abbrev = 0;
5135         else if (!strcmp(arg, "--abbrev"))
5136                 options->abbrev = DEFAULT_ABBREV;
5137         else if (skip_prefix(arg, "--abbrev=", &arg)) {
5138                 options->abbrev = strtoul(arg, NULL, 10);
5139                 if (options->abbrev < MINIMUM_ABBREV)
5140                         options->abbrev = MINIMUM_ABBREV;
5141                 else if (the_hash_algo->hexsz < options->abbrev)
5142                         options->abbrev = the_hash_algo->hexsz;
5143         }
5144         else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
5145                 options->a_prefix = optarg;
5146                 return argcount;
5147         }
5148         else if ((argcount = parse_long_opt("line-prefix", av, &optarg))) {
5149                 options->line_prefix = optarg;
5150                 options->line_prefix_length = strlen(options->line_prefix);
5151                 graph_setup_line_prefix(options);
5152                 return argcount;
5153         }
5154         else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
5155                 options->b_prefix = optarg;
5156                 return argcount;
5157         }
5158         else if (!strcmp(arg, "--no-prefix"))
5159                 options->a_prefix = options->b_prefix = "";
5160         else if (opt_arg(arg, '\0', "inter-hunk-context",
5161                          &options->interhunkcontext))
5162                 ;
5163         else if (!strcmp(arg, "-W"))
5164                 options->flags.funccontext = 1;
5165         else if (!strcmp(arg, "--function-context"))
5166                 options->flags.funccontext = 1;
5167         else if (!strcmp(arg, "--no-function-context"))
5168                 options->flags.funccontext = 0;
5169         else if ((argcount = parse_long_opt("output", av, &optarg))) {
5170                 char *path = prefix_filename(prefix, optarg);
5171                 options->file = xfopen(path, "w");
5172                 options->close_file = 1;
5173                 if (options->use_color != GIT_COLOR_ALWAYS)
5174                         options->use_color = GIT_COLOR_NEVER;
5175                 free(path);
5176                 return argcount;
5177         } else
5178                 return 0;
5179         return 1;
5180 }
5181
5182 int parse_rename_score(const char **cp_p)
5183 {
5184         unsigned long num, scale;
5185         int ch, dot;
5186         const char *cp = *cp_p;
5187
5188         num = 0;
5189         scale = 1;
5190         dot = 0;
5191         for (;;) {
5192                 ch = *cp;
5193                 if ( !dot && ch == '.' ) {
5194                         scale = 1;
5195                         dot = 1;
5196                 } else if ( ch == '%' ) {
5197                         scale = dot ? scale*100 : 100;
5198                         cp++;   /* % is always at the end */
5199                         break;
5200                 } else if ( ch >= '0' && ch <= '9' ) {
5201                         if ( scale < 100000 ) {
5202                                 scale *= 10;
5203                                 num = (num*10) + (ch-'0');
5204                         }
5205                 } else {
5206                         break;
5207                 }
5208                 cp++;
5209         }
5210         *cp_p = cp;
5211
5212         /* user says num divided by scale and we say internally that
5213          * is MAX_SCORE * num / scale.
5214          */
5215         return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
5216 }
5217
5218 static int diff_scoreopt_parse(const char *opt)
5219 {
5220         int opt1, opt2, cmd;
5221
5222         if (*opt++ != '-')
5223                 return -1;
5224         cmd = *opt++;
5225         if (cmd == '-') {
5226                 /* convert the long-form arguments into short-form versions */
5227                 if (skip_prefix(opt, "break-rewrites", &opt)) {
5228                         if (*opt == 0 || *opt++ == '=')
5229                                 cmd = 'B';
5230                 } else if (skip_prefix(opt, "find-copies", &opt)) {
5231                         if (*opt == 0 || *opt++ == '=')
5232                                 cmd = 'C';
5233                 } else if (skip_prefix(opt, "find-renames", &opt)) {
5234                         if (*opt == 0 || *opt++ == '=')
5235                                 cmd = 'M';
5236                 }
5237         }
5238         if (cmd != 'M' && cmd != 'C' && cmd != 'B')
5239                 return -1; /* that is not a -M, -C, or -B option */
5240
5241         opt1 = parse_rename_score(&opt);
5242         if (cmd != 'B')
5243                 opt2 = 0;
5244         else {
5245                 if (*opt == 0)
5246                         opt2 = 0;
5247                 else if (*opt != '/')
5248                         return -1; /* we expect -B80/99 or -B80 */
5249                 else {
5250                         opt++;
5251                         opt2 = parse_rename_score(&opt);
5252                 }
5253         }
5254         if (*opt != 0)
5255                 return -1;
5256         return opt1 | (opt2 << 16);
5257 }
5258
5259 struct diff_queue_struct diff_queued_diff;
5260
5261 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
5262 {
5263         ALLOC_GROW(queue->queue, queue->nr + 1, queue->alloc);
5264         queue->queue[queue->nr++] = dp;
5265 }
5266
5267 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
5268                                  struct diff_filespec *one,
5269                                  struct diff_filespec *two)
5270 {
5271         struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
5272         dp->one = one;
5273         dp->two = two;
5274         if (queue)
5275                 diff_q(queue, dp);
5276         return dp;
5277 }
5278
5279 void diff_free_filepair(struct diff_filepair *p)
5280 {
5281         free_filespec(p->one);
5282         free_filespec(p->two);
5283         free(p);
5284 }
5285
5286 const char *diff_aligned_abbrev(const struct object_id *oid, int len)
5287 {
5288         int abblen;
5289         const char *abbrev;
5290
5291         /* Do we want all 40 hex characters? */
5292         if (len == the_hash_algo->hexsz)
5293                 return oid_to_hex(oid);
5294
5295         /* An abbreviated value is fine, possibly followed by an ellipsis. */
5296         abbrev = diff_abbrev_oid(oid, len);
5297
5298         if (!print_sha1_ellipsis())
5299                 return abbrev;
5300
5301         abblen = strlen(abbrev);
5302
5303         /*
5304          * In well-behaved cases, where the abbreviated result is the
5305          * same as the requested length, append three dots after the
5306          * abbreviation (hence the whole logic is limited to the case
5307          * where abblen < 37); when the actual abbreviated result is a
5308          * bit longer than the requested length, we reduce the number
5309          * of dots so that they match the well-behaved ones.  However,
5310          * if the actual abbreviation is longer than the requested
5311          * length by more than three, we give up on aligning, and add
5312          * three dots anyway, to indicate that the output is not the
5313          * full object name.  Yes, this may be suboptimal, but this
5314          * appears only in "diff --raw --abbrev" output and it is not
5315          * worth the effort to change it now.  Note that this would
5316          * likely to work fine when the automatic sizing of default
5317          * abbreviation length is used--we would be fed -1 in "len" in
5318          * that case, and will end up always appending three-dots, but
5319          * the automatic sizing is supposed to give abblen that ensures
5320          * uniqueness across all objects (statistically speaking).
5321          */
5322         if (abblen < the_hash_algo->hexsz - 3) {
5323                 static char hex[GIT_MAX_HEXSZ + 1];
5324                 if (len < abblen && abblen <= len + 2)
5325                         xsnprintf(hex, sizeof(hex), "%s%.*s", abbrev, len+3-abblen, "..");
5326                 else
5327                         xsnprintf(hex, sizeof(hex), "%s...", abbrev);
5328                 return hex;
5329         }
5330
5331         return oid_to_hex(oid);
5332 }
5333
5334 static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
5335 {
5336         int line_termination = opt->line_termination;
5337         int inter_name_termination = line_termination ? '\t' : '\0';
5338
5339         fprintf(opt->file, "%s", diff_line_prefix(opt));
5340         if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
5341                 fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
5342                         diff_aligned_abbrev(&p->one->oid, opt->abbrev));
5343                 fprintf(opt->file, "%s ",
5344                         diff_aligned_abbrev(&p->two->oid, opt->abbrev));
5345         }
5346         if (p->score) {
5347                 fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
5348                         inter_name_termination);
5349         } else {
5350                 fprintf(opt->file, "%c%c", p->status, inter_name_termination);
5351         }
5352
5353         if (p->status == DIFF_STATUS_COPIED ||
5354             p->status == DIFF_STATUS_RENAMED) {
5355                 const char *name_a, *name_b;
5356                 name_a = p->one->path;
5357                 name_b = p->two->path;
5358                 strip_prefix(opt->prefix_length, &name_a, &name_b);
5359                 write_name_quoted(name_a, opt->file, inter_name_termination);
5360                 write_name_quoted(name_b, opt->file, line_termination);
5361         } else {
5362                 const char *name_a, *name_b;
5363                 name_a = p->one->mode ? p->one->path : p->two->path;
5364                 name_b = NULL;
5365                 strip_prefix(opt->prefix_length, &name_a, &name_b);
5366                 write_name_quoted(name_a, opt->file, line_termination);
5367         }
5368 }
5369
5370 int diff_unmodified_pair(struct diff_filepair *p)
5371 {
5372         /* This function is written stricter than necessary to support
5373          * the currently implemented transformers, but the idea is to
5374          * let transformers to produce diff_filepairs any way they want,
5375          * and filter and clean them up here before producing the output.
5376          */
5377         struct diff_filespec *one = p->one, *two = p->two;
5378
5379         if (DIFF_PAIR_UNMERGED(p))
5380                 return 0; /* unmerged is interesting */
5381
5382         /* deletion, addition, mode or type change
5383          * and rename are all interesting.
5384          */
5385         if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
5386             DIFF_PAIR_MODE_CHANGED(p) ||
5387             strcmp(one->path, two->path))
5388                 return 0;
5389
5390         /* both are valid and point at the same path.  that is, we are
5391          * dealing with a change.
5392          */
5393         if (one->oid_valid && two->oid_valid &&
5394             oideq(&one->oid, &two->oid) &&
5395             !one->dirty_submodule && !two->dirty_submodule)
5396                 return 1; /* no change */
5397         if (!one->oid_valid && !two->oid_valid)
5398                 return 1; /* both look at the same file on the filesystem. */
5399         return 0;
5400 }
5401
5402 static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
5403 {
5404         if (diff_unmodified_pair(p))
5405                 return;
5406
5407         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5408             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5409                 return; /* no tree diffs in patch format */
5410
5411         run_diff(p, o);
5412 }
5413
5414 static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
5415                             struct diffstat_t *diffstat)
5416 {
5417         if (diff_unmodified_pair(p))
5418                 return;
5419
5420         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5421             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5422                 return; /* no useful stat for tree diffs */
5423
5424         run_diffstat(p, o, diffstat);
5425 }
5426
5427 static void diff_flush_checkdiff(struct diff_filepair *p,
5428                 struct diff_options *o)
5429 {
5430         if (diff_unmodified_pair(p))
5431                 return;
5432
5433         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5434             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5435                 return; /* nothing to check in tree diffs */
5436
5437         run_checkdiff(p, o);
5438 }
5439
5440 int diff_queue_is_empty(void)
5441 {
5442         struct diff_queue_struct *q = &diff_queued_diff;
5443         int i;
5444         for (i = 0; i < q->nr; i++)
5445                 if (!diff_unmodified_pair(q->queue[i]))
5446                         return 0;
5447         return 1;
5448 }
5449
5450 #if DIFF_DEBUG
5451 void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
5452 {
5453         fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
5454                 x, one ? one : "",
5455                 s->path,
5456                 DIFF_FILE_VALID(s) ? "valid" : "invalid",
5457                 s->mode,
5458                 s->oid_valid ? oid_to_hex(&s->oid) : "");
5459         fprintf(stderr, "queue[%d] %s size %lu\n",
5460                 x, one ? one : "",
5461                 s->size);
5462 }
5463
5464 void diff_debug_filepair(const struct diff_filepair *p, int i)
5465 {
5466         diff_debug_filespec(p->one, i, "one");
5467         diff_debug_filespec(p->two, i, "two");
5468         fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
5469                 p->score, p->status ? p->status : '?',
5470                 p->one->rename_used, p->broken_pair);
5471 }
5472
5473 void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
5474 {
5475         int i;
5476         if (msg)
5477                 fprintf(stderr, "%s\n", msg);
5478         fprintf(stderr, "q->nr = %d\n", q->nr);
5479         for (i = 0; i < q->nr; i++) {
5480                 struct diff_filepair *p = q->queue[i];
5481                 diff_debug_filepair(p, i);
5482         }
5483 }
5484 #endif
5485
5486 static void diff_resolve_rename_copy(void)
5487 {
5488         int i;
5489         struct diff_filepair *p;
5490         struct diff_queue_struct *q = &diff_queued_diff;
5491
5492         diff_debug_queue("resolve-rename-copy", q);
5493
5494         for (i = 0; i < q->nr; i++) {
5495                 p = q->queue[i];
5496                 p->status = 0; /* undecided */
5497                 if (DIFF_PAIR_UNMERGED(p))
5498                         p->status = DIFF_STATUS_UNMERGED;
5499                 else if (!DIFF_FILE_VALID(p->one))
5500                         p->status = DIFF_STATUS_ADDED;
5501                 else if (!DIFF_FILE_VALID(p->two))
5502                         p->status = DIFF_STATUS_DELETED;
5503                 else if (DIFF_PAIR_TYPE_CHANGED(p))
5504                         p->status = DIFF_STATUS_TYPE_CHANGED;
5505
5506                 /* from this point on, we are dealing with a pair
5507                  * whose both sides are valid and of the same type, i.e.
5508                  * either in-place edit or rename/copy edit.
5509                  */
5510                 else if (DIFF_PAIR_RENAME(p)) {
5511                         /*
5512                          * A rename might have re-connected a broken
5513                          * pair up, causing the pathnames to be the
5514                          * same again. If so, that's not a rename at
5515                          * all, just a modification..
5516                          *
5517                          * Otherwise, see if this source was used for
5518                          * multiple renames, in which case we decrement
5519                          * the count, and call it a copy.
5520                          */
5521                         if (!strcmp(p->one->path, p->two->path))
5522                                 p->status = DIFF_STATUS_MODIFIED;
5523                         else if (--p->one->rename_used > 0)
5524                                 p->status = DIFF_STATUS_COPIED;
5525                         else
5526                                 p->status = DIFF_STATUS_RENAMED;
5527                 }
5528                 else if (!oideq(&p->one->oid, &p->two->oid) ||
5529                          p->one->mode != p->two->mode ||
5530                          p->one->dirty_submodule ||
5531                          p->two->dirty_submodule ||
5532                          is_null_oid(&p->one->oid))
5533                         p->status = DIFF_STATUS_MODIFIED;
5534                 else {
5535                         /* This is a "no-change" entry and should not
5536                          * happen anymore, but prepare for broken callers.
5537                          */
5538                         error("feeding unmodified %s to diffcore",
5539                               p->one->path);
5540                         p->status = DIFF_STATUS_UNKNOWN;
5541                 }
5542         }
5543         diff_debug_queue("resolve-rename-copy done", q);
5544 }
5545
5546 static int check_pair_status(struct diff_filepair *p)
5547 {
5548         switch (p->status) {
5549         case DIFF_STATUS_UNKNOWN:
5550                 return 0;
5551         case 0:
5552                 die("internal error in diff-resolve-rename-copy");
5553         default:
5554                 return 1;
5555         }
5556 }
5557
5558 static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
5559 {
5560         int fmt = opt->output_format;
5561
5562         if (fmt & DIFF_FORMAT_CHECKDIFF)
5563                 diff_flush_checkdiff(p, opt);
5564         else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
5565                 diff_flush_raw(p, opt);
5566         else if (fmt & DIFF_FORMAT_NAME) {
5567                 const char *name_a, *name_b;
5568                 name_a = p->two->path;
5569                 name_b = NULL;
5570                 strip_prefix(opt->prefix_length, &name_a, &name_b);
5571                 fprintf(opt->file, "%s", diff_line_prefix(opt));
5572                 write_name_quoted(name_a, opt->file, opt->line_termination);
5573         }
5574 }
5575
5576 static void show_file_mode_name(struct diff_options *opt, const char *newdelete, struct diff_filespec *fs)
5577 {
5578         struct strbuf sb = STRBUF_INIT;
5579         if (fs->mode)
5580                 strbuf_addf(&sb, " %s mode %06o ", newdelete, fs->mode);
5581         else
5582                 strbuf_addf(&sb, " %s ", newdelete);
5583
5584         quote_c_style(fs->path, &sb, NULL, 0);
5585         strbuf_addch(&sb, '\n');
5586         emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5587                          sb.buf, sb.len, 0);
5588         strbuf_release(&sb);
5589 }
5590
5591 static void show_mode_change(struct diff_options *opt, struct diff_filepair *p,
5592                 int show_name)
5593 {
5594         if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
5595                 struct strbuf sb = STRBUF_INIT;
5596                 strbuf_addf(&sb, " mode change %06o => %06o",
5597                             p->one->mode, p->two->mode);
5598                 if (show_name) {
5599                         strbuf_addch(&sb, ' ');
5600                         quote_c_style(p->two->path, &sb, NULL, 0);
5601                 }
5602                 strbuf_addch(&sb, '\n');
5603                 emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5604                                  sb.buf, sb.len, 0);
5605                 strbuf_release(&sb);
5606         }
5607 }
5608
5609 static void show_rename_copy(struct diff_options *opt, const char *renamecopy,
5610                 struct diff_filepair *p)
5611 {
5612         struct strbuf sb = STRBUF_INIT;
5613         struct strbuf names = STRBUF_INIT;
5614
5615         pprint_rename(&names, p->one->path, p->two->path);
5616         strbuf_addf(&sb, " %s %s (%d%%)\n",
5617                     renamecopy, names.buf, similarity_index(p));
5618         strbuf_release(&names);
5619         emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5620                                  sb.buf, sb.len, 0);
5621         show_mode_change(opt, p, 0);
5622         strbuf_release(&sb);
5623 }
5624
5625 static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
5626 {
5627         switch(p->status) {
5628         case DIFF_STATUS_DELETED:
5629                 show_file_mode_name(opt, "delete", p->one);
5630                 break;
5631         case DIFF_STATUS_ADDED:
5632                 show_file_mode_name(opt, "create", p->two);
5633                 break;
5634         case DIFF_STATUS_COPIED:
5635                 show_rename_copy(opt, "copy", p);
5636                 break;
5637         case DIFF_STATUS_RENAMED:
5638                 show_rename_copy(opt, "rename", p);
5639                 break;
5640         default:
5641                 if (p->score) {
5642                         struct strbuf sb = STRBUF_INIT;
5643                         strbuf_addstr(&sb, " rewrite ");
5644                         quote_c_style(p->two->path, &sb, NULL, 0);
5645                         strbuf_addf(&sb, " (%d%%)\n", similarity_index(p));
5646                         emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5647                                          sb.buf, sb.len, 0);
5648                         strbuf_release(&sb);
5649                 }
5650                 show_mode_change(opt, p, !p->score);
5651                 break;
5652         }
5653 }
5654
5655 struct patch_id_t {
5656         git_SHA_CTX *ctx;
5657         int patchlen;
5658 };
5659
5660 static int remove_space(char *line, int len)
5661 {
5662         int i;
5663         char *dst = line;
5664         unsigned char c;
5665
5666         for (i = 0; i < len; i++)
5667                 if (!isspace((c = line[i])))
5668                         *dst++ = c;
5669
5670         return dst - line;
5671 }
5672
5673 static void patch_id_consume(void *priv, char *line, unsigned long len)
5674 {
5675         struct patch_id_t *data = priv;
5676         int new_len;
5677
5678         new_len = remove_space(line, len);
5679
5680         git_SHA1_Update(data->ctx, line, new_len);
5681         data->patchlen += new_len;
5682 }
5683
5684 static void patch_id_add_string(git_SHA_CTX *ctx, const char *str)
5685 {
5686         git_SHA1_Update(ctx, str, strlen(str));
5687 }
5688
5689 static void patch_id_add_mode(git_SHA_CTX *ctx, unsigned mode)
5690 {
5691         /* large enough for 2^32 in octal */
5692         char buf[12];
5693         int len = xsnprintf(buf, sizeof(buf), "%06o", mode);
5694         git_SHA1_Update(ctx, buf, len);
5695 }
5696
5697 /* returns 0 upon success, and writes result into sha1 */
5698 static int diff_get_patch_id(struct diff_options *options, struct object_id *oid, int diff_header_only)
5699 {
5700         struct diff_queue_struct *q = &diff_queued_diff;
5701         int i;
5702         git_SHA_CTX ctx;
5703         struct patch_id_t data;
5704
5705         git_SHA1_Init(&ctx);
5706         memset(&data, 0, sizeof(struct patch_id_t));
5707         data.ctx = &ctx;
5708
5709         for (i = 0; i < q->nr; i++) {
5710                 xpparam_t xpp;
5711                 xdemitconf_t xecfg;
5712                 mmfile_t mf1, mf2;
5713                 struct diff_filepair *p = q->queue[i];
5714                 int len1, len2;
5715
5716                 memset(&xpp, 0, sizeof(xpp));
5717                 memset(&xecfg, 0, sizeof(xecfg));
5718                 if (p->status == 0)
5719                         return error("internal diff status error");
5720                 if (p->status == DIFF_STATUS_UNKNOWN)
5721                         continue;
5722                 if (diff_unmodified_pair(p))
5723                         continue;
5724                 if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5725                     (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5726                         continue;
5727                 if (DIFF_PAIR_UNMERGED(p))
5728                         continue;
5729
5730                 diff_fill_oid_info(p->one, options->repo->index);
5731                 diff_fill_oid_info(p->two, options->repo->index);
5732
5733                 len1 = remove_space(p->one->path, strlen(p->one->path));
5734                 len2 = remove_space(p->two->path, strlen(p->two->path));
5735                 patch_id_add_string(&ctx, "diff--git");
5736                 patch_id_add_string(&ctx, "a/");
5737                 git_SHA1_Update(&ctx, p->one->path, len1);
5738                 patch_id_add_string(&ctx, "b/");
5739                 git_SHA1_Update(&ctx, p->two->path, len2);
5740
5741                 if (p->one->mode == 0) {
5742                         patch_id_add_string(&ctx, "newfilemode");
5743                         patch_id_add_mode(&ctx, p->two->mode);
5744                         patch_id_add_string(&ctx, "---/dev/null");
5745                         patch_id_add_string(&ctx, "+++b/");
5746                         git_SHA1_Update(&ctx, p->two->path, len2);
5747                 } else if (p->two->mode == 0) {
5748                         patch_id_add_string(&ctx, "deletedfilemode");
5749                         patch_id_add_mode(&ctx, p->one->mode);
5750                         patch_id_add_string(&ctx, "---a/");
5751                         git_SHA1_Update(&ctx, p->one->path, len1);
5752                         patch_id_add_string(&ctx, "+++/dev/null");
5753                 } else {
5754                         patch_id_add_string(&ctx, "---a/");
5755                         git_SHA1_Update(&ctx, p->one->path, len1);
5756                         patch_id_add_string(&ctx, "+++b/");
5757                         git_SHA1_Update(&ctx, p->two->path, len2);
5758                 }
5759
5760                 if (diff_header_only)
5761                         continue;
5762
5763                 if (fill_mmfile(options->repo, &mf1, p->one) < 0 ||
5764                     fill_mmfile(options->repo, &mf2, p->two) < 0)
5765                         return error("unable to read files to diff");
5766
5767                 if (diff_filespec_is_binary(options->repo, p->one) ||
5768                     diff_filespec_is_binary(options->repo, p->two)) {
5769                         git_SHA1_Update(&ctx, oid_to_hex(&p->one->oid),
5770                                         GIT_SHA1_HEXSZ);
5771                         git_SHA1_Update(&ctx, oid_to_hex(&p->two->oid),
5772                                         GIT_SHA1_HEXSZ);
5773                         continue;
5774                 }
5775
5776                 xpp.flags = 0;
5777                 xecfg.ctxlen = 3;
5778                 xecfg.flags = 0;
5779                 if (xdi_diff_outf(&mf1, &mf2, discard_hunk_line,
5780                                   patch_id_consume, &data, &xpp, &xecfg))
5781                         return error("unable to generate patch-id diff for %s",
5782                                      p->one->path);
5783         }
5784
5785         git_SHA1_Final(oid->hash, &ctx);
5786         return 0;
5787 }
5788
5789 int diff_flush_patch_id(struct diff_options *options, struct object_id *oid, int diff_header_only)
5790 {
5791         struct diff_queue_struct *q = &diff_queued_diff;
5792         int i;
5793         int result = diff_get_patch_id(options, oid, diff_header_only);
5794
5795         for (i = 0; i < q->nr; i++)
5796                 diff_free_filepair(q->queue[i]);
5797
5798         free(q->queue);
5799         DIFF_QUEUE_CLEAR(q);
5800
5801         return result;
5802 }
5803
5804 static int is_summary_empty(const struct diff_queue_struct *q)
5805 {
5806         int i;
5807
5808         for (i = 0; i < q->nr; i++) {
5809                 const struct diff_filepair *p = q->queue[i];
5810
5811                 switch (p->status) {
5812                 case DIFF_STATUS_DELETED:
5813                 case DIFF_STATUS_ADDED:
5814                 case DIFF_STATUS_COPIED:
5815                 case DIFF_STATUS_RENAMED:
5816                         return 0;
5817                 default:
5818                         if (p->score)
5819                                 return 0;
5820                         if (p->one->mode && p->two->mode &&
5821                             p->one->mode != p->two->mode)
5822                                 return 0;
5823                         break;
5824                 }
5825         }
5826         return 1;
5827 }
5828
5829 static const char rename_limit_warning[] =
5830 N_("inexact rename detection was skipped due to too many files.");
5831
5832 static const char degrade_cc_to_c_warning[] =
5833 N_("only found copies from modified paths due to too many files.");
5834
5835 static const char rename_limit_advice[] =
5836 N_("you may want to set your %s variable to at least "
5837    "%d and retry the command.");
5838
5839 void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
5840 {
5841         fflush(stdout);
5842         if (degraded_cc)
5843                 warning(_(degrade_cc_to_c_warning));
5844         else if (needed)
5845                 warning(_(rename_limit_warning));
5846         else
5847                 return;
5848         if (0 < needed)
5849                 warning(_(rename_limit_advice), varname, needed);
5850 }
5851
5852 static void diff_flush_patch_all_file_pairs(struct diff_options *o)
5853 {
5854         int i;
5855         static struct emitted_diff_symbols esm = EMITTED_DIFF_SYMBOLS_INIT;
5856         struct diff_queue_struct *q = &diff_queued_diff;
5857
5858         if (WSEH_NEW & WS_RULE_MASK)
5859                 BUG("WS rules bit mask overlaps with diff symbol flags");
5860
5861         if (o->color_moved)
5862                 o->emitted_symbols = &esm;
5863
5864         for (i = 0; i < q->nr; i++) {
5865                 struct diff_filepair *p = q->queue[i];
5866                 if (check_pair_status(p))
5867                         diff_flush_patch(p, o);
5868         }
5869
5870         if (o->emitted_symbols) {
5871                 if (o->color_moved) {
5872                         struct hashmap add_lines, del_lines;
5873
5874                         if (o->color_moved_ws_handling &
5875                             COLOR_MOVED_WS_ALLOW_INDENTATION_CHANGE)
5876                                 o->color_moved_ws_handling |= XDF_IGNORE_WHITESPACE;
5877
5878                         hashmap_init(&del_lines, moved_entry_cmp, o, 0);
5879                         hashmap_init(&add_lines, moved_entry_cmp, o, 0);
5880
5881                         add_lines_to_move_detection(o, &add_lines, &del_lines);
5882                         mark_color_as_moved(o, &add_lines, &del_lines);
5883                         if (o->color_moved == COLOR_MOVED_ZEBRA_DIM)
5884                                 dim_moved_lines(o);
5885
5886                         hashmap_free(&add_lines, 1);
5887                         hashmap_free(&del_lines, 1);
5888                 }
5889
5890                 for (i = 0; i < esm.nr; i++)
5891                         emit_diff_symbol_from_struct(o, &esm.buf[i]);
5892
5893                 for (i = 0; i < esm.nr; i++)
5894                         free((void *)esm.buf[i].line);
5895         }
5896         esm.nr = 0;
5897 }
5898
5899 void diff_flush(struct diff_options *options)
5900 {
5901         struct diff_queue_struct *q = &diff_queued_diff;
5902         int i, output_format = options->output_format;
5903         int separator = 0;
5904         int dirstat_by_line = 0;
5905
5906         /*
5907          * Order: raw, stat, summary, patch
5908          * or:    name/name-status/checkdiff (other bits clear)
5909          */
5910         if (!q->nr)
5911                 goto free_queue;
5912
5913         if (output_format & (DIFF_FORMAT_RAW |
5914                              DIFF_FORMAT_NAME |
5915                              DIFF_FORMAT_NAME_STATUS |
5916                              DIFF_FORMAT_CHECKDIFF)) {
5917                 for (i = 0; i < q->nr; i++) {
5918                         struct diff_filepair *p = q->queue[i];
5919                         if (check_pair_status(p))
5920                                 flush_one_pair(p, options);
5921                 }
5922                 separator++;
5923         }
5924
5925         if (output_format & DIFF_FORMAT_DIRSTAT && options->flags.dirstat_by_line)
5926                 dirstat_by_line = 1;
5927
5928         if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
5929             dirstat_by_line) {
5930                 struct diffstat_t diffstat;
5931
5932                 memset(&diffstat, 0, sizeof(struct diffstat_t));
5933                 for (i = 0; i < q->nr; i++) {
5934                         struct diff_filepair *p = q->queue[i];
5935                         if (check_pair_status(p))
5936                                 diff_flush_stat(p, options, &diffstat);
5937                 }
5938                 if (output_format & DIFF_FORMAT_NUMSTAT)
5939                         show_numstat(&diffstat, options);
5940                 if (output_format & DIFF_FORMAT_DIFFSTAT)
5941                         show_stats(&diffstat, options);
5942                 if (output_format & DIFF_FORMAT_SHORTSTAT)
5943                         show_shortstats(&diffstat, options);
5944                 if (output_format & DIFF_FORMAT_DIRSTAT && dirstat_by_line)
5945                         show_dirstat_by_line(&diffstat, options);
5946                 free_diffstat_info(&diffstat);
5947                 separator++;
5948         }
5949         if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
5950                 show_dirstat(options);
5951
5952         if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
5953                 for (i = 0; i < q->nr; i++) {
5954                         diff_summary(options, q->queue[i]);
5955                 }
5956                 separator++;
5957         }
5958
5959         if (output_format & DIFF_FORMAT_NO_OUTPUT &&
5960             options->flags.exit_with_status &&
5961             options->flags.diff_from_contents) {
5962                 /*
5963                  * run diff_flush_patch for the exit status. setting
5964                  * options->file to /dev/null should be safe, because we
5965                  * aren't supposed to produce any output anyway.
5966                  */
5967                 if (options->close_file)
5968                         fclose(options->file);
5969                 options->file = xfopen("/dev/null", "w");
5970                 options->close_file = 1;
5971                 options->color_moved = 0;
5972                 for (i = 0; i < q->nr; i++) {
5973                         struct diff_filepair *p = q->queue[i];
5974                         if (check_pair_status(p))
5975                                 diff_flush_patch(p, options);
5976                         if (options->found_changes)
5977                                 break;
5978                 }
5979         }
5980
5981         if (output_format & DIFF_FORMAT_PATCH) {
5982                 if (separator) {
5983                         emit_diff_symbol(options, DIFF_SYMBOL_SEPARATOR, NULL, 0, 0);
5984                         if (options->stat_sep)
5985                                 /* attach patch instead of inline */
5986                                 emit_diff_symbol(options, DIFF_SYMBOL_STAT_SEP,
5987                                                  NULL, 0, 0);
5988                 }
5989
5990                 diff_flush_patch_all_file_pairs(options);
5991         }
5992
5993         if (output_format & DIFF_FORMAT_CALLBACK)
5994                 options->format_callback(q, options, options->format_callback_data);
5995
5996         for (i = 0; i < q->nr; i++)
5997                 diff_free_filepair(q->queue[i]);
5998 free_queue:
5999         free(q->queue);
6000         DIFF_QUEUE_CLEAR(q);
6001         if (options->close_file)
6002                 fclose(options->file);
6003
6004         /*
6005          * Report the content-level differences with HAS_CHANGES;
6006          * diff_addremove/diff_change does not set the bit when
6007          * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
6008          */
6009         if (options->flags.diff_from_contents) {
6010                 if (options->found_changes)
6011                         options->flags.has_changes = 1;
6012                 else
6013                         options->flags.has_changes = 0;
6014         }
6015 }
6016
6017 static int match_filter(const struct diff_options *options, const struct diff_filepair *p)
6018 {
6019         return (((p->status == DIFF_STATUS_MODIFIED) &&
6020                  ((p->score &&
6021                    filter_bit_tst(DIFF_STATUS_FILTER_BROKEN, options)) ||
6022                   (!p->score &&
6023                    filter_bit_tst(DIFF_STATUS_MODIFIED, options)))) ||
6024                 ((p->status != DIFF_STATUS_MODIFIED) &&
6025                  filter_bit_tst(p->status, options)));
6026 }
6027
6028 static void diffcore_apply_filter(struct diff_options *options)
6029 {
6030         int i;
6031         struct diff_queue_struct *q = &diff_queued_diff;
6032         struct diff_queue_struct outq;
6033
6034         DIFF_QUEUE_CLEAR(&outq);
6035
6036         if (!options->filter)
6037                 return;
6038
6039         if (filter_bit_tst(DIFF_STATUS_FILTER_AON, options)) {
6040                 int found;
6041                 for (i = found = 0; !found && i < q->nr; i++) {
6042                         if (match_filter(options, q->queue[i]))
6043                                 found++;
6044                 }
6045                 if (found)
6046                         return;
6047
6048                 /* otherwise we will clear the whole queue
6049                  * by copying the empty outq at the end of this
6050                  * function, but first clear the current entries
6051                  * in the queue.
6052                  */
6053                 for (i = 0; i < q->nr; i++)
6054                         diff_free_filepair(q->queue[i]);
6055         }
6056         else {
6057                 /* Only the matching ones */
6058                 for (i = 0; i < q->nr; i++) {
6059                         struct diff_filepair *p = q->queue[i];
6060                         if (match_filter(options, p))
6061                                 diff_q(&outq, p);
6062                         else
6063                                 diff_free_filepair(p);
6064                 }
6065         }
6066         free(q->queue);
6067         *q = outq;
6068 }
6069
6070 /* Check whether two filespecs with the same mode and size are identical */
6071 static int diff_filespec_is_identical(struct repository *r,
6072                                       struct diff_filespec *one,
6073                                       struct diff_filespec *two)
6074 {
6075         if (S_ISGITLINK(one->mode))
6076                 return 0;
6077         if (diff_populate_filespec(r, one, 0))
6078                 return 0;
6079         if (diff_populate_filespec(r, two, 0))
6080                 return 0;
6081         return !memcmp(one->data, two->data, one->size);
6082 }
6083
6084 static int diff_filespec_check_stat_unmatch(struct repository *r,
6085                                             struct diff_filepair *p)
6086 {
6087         if (p->done_skip_stat_unmatch)
6088                 return p->skip_stat_unmatch_result;
6089
6090         p->done_skip_stat_unmatch = 1;
6091         p->skip_stat_unmatch_result = 0;
6092         /*
6093          * 1. Entries that come from stat info dirtiness
6094          *    always have both sides (iow, not create/delete),
6095          *    one side of the object name is unknown, with
6096          *    the same mode and size.  Keep the ones that
6097          *    do not match these criteria.  They have real
6098          *    differences.
6099          *
6100          * 2. At this point, the file is known to be modified,
6101          *    with the same mode and size, and the object
6102          *    name of one side is unknown.  Need to inspect
6103          *    the identical contents.
6104          */
6105         if (!DIFF_FILE_VALID(p->one) || /* (1) */
6106             !DIFF_FILE_VALID(p->two) ||
6107             (p->one->oid_valid && p->two->oid_valid) ||
6108             (p->one->mode != p->two->mode) ||
6109             diff_populate_filespec(r, p->one, CHECK_SIZE_ONLY) ||
6110             diff_populate_filespec(r, p->two, CHECK_SIZE_ONLY) ||
6111             (p->one->size != p->two->size) ||
6112             !diff_filespec_is_identical(r, p->one, p->two)) /* (2) */
6113                 p->skip_stat_unmatch_result = 1;
6114         return p->skip_stat_unmatch_result;
6115 }
6116
6117 static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
6118 {
6119         int i;
6120         struct diff_queue_struct *q = &diff_queued_diff;
6121         struct diff_queue_struct outq;
6122         DIFF_QUEUE_CLEAR(&outq);
6123
6124         for (i = 0; i < q->nr; i++) {
6125                 struct diff_filepair *p = q->queue[i];
6126
6127                 if (diff_filespec_check_stat_unmatch(diffopt->repo, p))
6128                         diff_q(&outq, p);
6129                 else {
6130                         /*
6131                          * The caller can subtract 1 from skip_stat_unmatch
6132                          * to determine how many paths were dirty only
6133                          * due to stat info mismatch.
6134                          */
6135                         if (!diffopt->flags.no_index)
6136                                 diffopt->skip_stat_unmatch++;
6137                         diff_free_filepair(p);
6138                 }
6139         }
6140         free(q->queue);
6141         *q = outq;
6142 }
6143
6144 static int diffnamecmp(const void *a_, const void *b_)
6145 {
6146         const struct diff_filepair *a = *((const struct diff_filepair **)a_);
6147         const struct diff_filepair *b = *((const struct diff_filepair **)b_);
6148         const char *name_a, *name_b;
6149
6150         name_a = a->one ? a->one->path : a->two->path;
6151         name_b = b->one ? b->one->path : b->two->path;
6152         return strcmp(name_a, name_b);
6153 }
6154
6155 void diffcore_fix_diff_index(struct diff_options *options)
6156 {
6157         struct diff_queue_struct *q = &diff_queued_diff;
6158         QSORT(q->queue, q->nr, diffnamecmp);
6159 }
6160
6161 void diffcore_std(struct diff_options *options)
6162 {
6163         /* NOTE please keep the following in sync with diff_tree_combined() */
6164         if (options->skip_stat_unmatch)
6165                 diffcore_skip_stat_unmatch(options);
6166         if (!options->found_follow) {
6167                 /* See try_to_follow_renames() in tree-diff.c */
6168                 if (options->break_opt != -1)
6169                         diffcore_break(options->repo,
6170                                        options->break_opt);
6171                 if (options->detect_rename)
6172                         diffcore_rename(options);
6173                 if (options->break_opt != -1)
6174                         diffcore_merge_broken();
6175         }
6176         if (options->pickaxe_opts & DIFF_PICKAXE_KINDS_MASK)
6177                 diffcore_pickaxe(options);
6178         if (options->orderfile)
6179                 diffcore_order(options->orderfile);
6180         if (!options->found_follow)
6181                 /* See try_to_follow_renames() in tree-diff.c */
6182                 diff_resolve_rename_copy();
6183         diffcore_apply_filter(options);
6184
6185         if (diff_queued_diff.nr && !options->flags.diff_from_contents)
6186                 options->flags.has_changes = 1;
6187         else
6188                 options->flags.has_changes = 0;
6189
6190         options->found_follow = 0;
6191 }
6192
6193 int diff_result_code(struct diff_options *opt, int status)
6194 {
6195         int result = 0;
6196
6197         diff_warn_rename_limit("diff.renameLimit",
6198                                opt->needed_rename_limit,
6199                                opt->degraded_cc_to_c);
6200         if (!opt->flags.exit_with_status &&
6201             !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
6202                 return status;
6203         if (opt->flags.exit_with_status &&
6204             opt->flags.has_changes)
6205                 result |= 01;
6206         if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
6207             opt->flags.check_failed)
6208                 result |= 02;
6209         return result;
6210 }
6211
6212 int diff_can_quit_early(struct diff_options *opt)
6213 {
6214         return (opt->flags.quick &&
6215                 !opt->filter &&
6216                 opt->flags.has_changes);
6217 }
6218
6219 /*
6220  * Shall changes to this submodule be ignored?
6221  *
6222  * Submodule changes can be configured to be ignored separately for each path,
6223  * but that configuration can be overridden from the command line.
6224  */
6225 static int is_submodule_ignored(const char *path, struct diff_options *options)
6226 {
6227         int ignored = 0;
6228         struct diff_flags orig_flags = options->flags;
6229         if (!options->flags.override_submodule_config)
6230                 set_diffopt_flags_from_submodule_config(options, path);
6231         if (options->flags.ignore_submodules)
6232                 ignored = 1;
6233         options->flags = orig_flags;
6234         return ignored;
6235 }
6236
6237 void diff_addremove(struct diff_options *options,
6238                     int addremove, unsigned mode,
6239                     const struct object_id *oid,
6240                     int oid_valid,
6241                     const char *concatpath, unsigned dirty_submodule)
6242 {
6243         struct diff_filespec *one, *two;
6244
6245         if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
6246                 return;
6247
6248         /* This may look odd, but it is a preparation for
6249          * feeding "there are unchanged files which should
6250          * not produce diffs, but when you are doing copy
6251          * detection you would need them, so here they are"
6252          * entries to the diff-core.  They will be prefixed
6253          * with something like '=' or '*' (I haven't decided
6254          * which but should not make any difference).
6255          * Feeding the same new and old to diff_change()
6256          * also has the same effect.
6257          * Before the final output happens, they are pruned after
6258          * merged into rename/copy pairs as appropriate.
6259          */
6260         if (options->flags.reverse_diff)
6261                 addremove = (addremove == '+' ? '-' :
6262                              addremove == '-' ? '+' : addremove);
6263
6264         if (options->prefix &&
6265             strncmp(concatpath, options->prefix, options->prefix_length))
6266                 return;
6267
6268         one = alloc_filespec(concatpath);
6269         two = alloc_filespec(concatpath);
6270
6271         if (addremove != '+')
6272                 fill_filespec(one, oid, oid_valid, mode);
6273         if (addremove != '-') {
6274                 fill_filespec(two, oid, oid_valid, mode);
6275                 two->dirty_submodule = dirty_submodule;
6276         }
6277
6278         diff_queue(&diff_queued_diff, one, two);
6279         if (!options->flags.diff_from_contents)
6280                 options->flags.has_changes = 1;
6281 }
6282
6283 void diff_change(struct diff_options *options,
6284                  unsigned old_mode, unsigned new_mode,
6285                  const struct object_id *old_oid,
6286                  const struct object_id *new_oid,
6287                  int old_oid_valid, int new_oid_valid,
6288                  const char *concatpath,
6289                  unsigned old_dirty_submodule, unsigned new_dirty_submodule)
6290 {
6291         struct diff_filespec *one, *two;
6292         struct diff_filepair *p;
6293
6294         if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
6295             is_submodule_ignored(concatpath, options))
6296                 return;
6297
6298         if (options->flags.reverse_diff) {
6299                 SWAP(old_mode, new_mode);
6300                 SWAP(old_oid, new_oid);
6301                 SWAP(old_oid_valid, new_oid_valid);
6302                 SWAP(old_dirty_submodule, new_dirty_submodule);
6303         }
6304
6305         if (options->prefix &&
6306             strncmp(concatpath, options->prefix, options->prefix_length))
6307                 return;
6308
6309         one = alloc_filespec(concatpath);
6310         two = alloc_filespec(concatpath);
6311         fill_filespec(one, old_oid, old_oid_valid, old_mode);
6312         fill_filespec(two, new_oid, new_oid_valid, new_mode);
6313         one->dirty_submodule = old_dirty_submodule;
6314         two->dirty_submodule = new_dirty_submodule;
6315         p = diff_queue(&diff_queued_diff, one, two);
6316
6317         if (options->flags.diff_from_contents)
6318                 return;
6319
6320         if (options->flags.quick && options->skip_stat_unmatch &&
6321             !diff_filespec_check_stat_unmatch(options->repo, p))
6322                 return;
6323
6324         options->flags.has_changes = 1;
6325 }
6326
6327 struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
6328 {
6329         struct diff_filepair *pair;
6330         struct diff_filespec *one, *two;
6331
6332         if (options->prefix &&
6333             strncmp(path, options->prefix, options->prefix_length))
6334                 return NULL;
6335
6336         one = alloc_filespec(path);
6337         two = alloc_filespec(path);
6338         pair = diff_queue(&diff_queued_diff, one, two);
6339         pair->is_unmerged = 1;
6340         return pair;
6341 }
6342
6343 static char *run_textconv(struct repository *r,
6344                           const char *pgm,
6345                           struct diff_filespec *spec,
6346                           size_t *outsize)
6347 {
6348         struct diff_tempfile *temp;
6349         const char *argv[3];
6350         const char **arg = argv;
6351         struct child_process child = CHILD_PROCESS_INIT;
6352         struct strbuf buf = STRBUF_INIT;
6353         int err = 0;
6354
6355         temp = prepare_temp_file(r, spec->path, spec);
6356         *arg++ = pgm;
6357         *arg++ = temp->name;
6358         *arg = NULL;
6359
6360         child.use_shell = 1;
6361         child.argv = argv;
6362         child.out = -1;
6363         if (start_command(&child)) {
6364                 remove_tempfile();
6365                 return NULL;
6366         }
6367
6368         if (strbuf_read(&buf, child.out, 0) < 0)
6369                 err = error("error reading from textconv command '%s'", pgm);
6370         close(child.out);
6371
6372         if (finish_command(&child) || err) {
6373                 strbuf_release(&buf);
6374                 remove_tempfile();
6375                 return NULL;
6376         }
6377         remove_tempfile();
6378
6379         return strbuf_detach(&buf, outsize);
6380 }
6381
6382 size_t fill_textconv(struct repository *r,
6383                      struct userdiff_driver *driver,
6384                      struct diff_filespec *df,
6385                      char **outbuf)
6386 {
6387         size_t size;
6388
6389         if (!driver) {
6390                 if (!DIFF_FILE_VALID(df)) {
6391                         *outbuf = "";
6392                         return 0;
6393                 }
6394                 if (diff_populate_filespec(r, df, 0))
6395                         die("unable to read files to diff");
6396                 *outbuf = df->data;
6397                 return df->size;
6398         }
6399
6400         if (!driver->textconv)
6401                 BUG("fill_textconv called with non-textconv driver");
6402
6403         if (driver->textconv_cache && df->oid_valid) {
6404                 *outbuf = notes_cache_get(driver->textconv_cache,
6405                                           &df->oid,
6406                                           &size);
6407                 if (*outbuf)
6408                         return size;
6409         }
6410
6411         *outbuf = run_textconv(r, driver->textconv, df, &size);
6412         if (!*outbuf)
6413                 die("unable to read files to diff");
6414
6415         if (driver->textconv_cache && df->oid_valid) {
6416                 /* ignore errors, as we might be in a readonly repository */
6417                 notes_cache_put(driver->textconv_cache, &df->oid, *outbuf,
6418                                 size);
6419                 /*
6420                  * we could save up changes and flush them all at the end,
6421                  * but we would need an extra call after all diffing is done.
6422                  * Since generating a cache entry is the slow path anyway,
6423                  * this extra overhead probably isn't a big deal.
6424                  */
6425                 notes_cache_write(driver->textconv_cache);
6426         }
6427
6428         return size;
6429 }
6430
6431 int textconv_object(struct repository *r,
6432                     const char *path,
6433                     unsigned mode,
6434                     const struct object_id *oid,
6435                     int oid_valid,
6436                     char **buf,
6437                     unsigned long *buf_size)
6438 {
6439         struct diff_filespec *df;
6440         struct userdiff_driver *textconv;
6441
6442         df = alloc_filespec(path);
6443         fill_filespec(df, oid, oid_valid, mode);
6444         textconv = get_textconv(r->index, df);
6445         if (!textconv) {
6446                 free_filespec(df);
6447                 return 0;
6448         }
6449
6450         *buf_size = fill_textconv(r, textconv, df, buf);
6451         free_filespec(df);
6452         return 1;
6453 }
6454
6455 void setup_diff_pager(struct diff_options *opt)
6456 {
6457         /*
6458          * If the user asked for our exit code, then either they want --quiet
6459          * or --exit-code. We should definitely not bother with a pager in the
6460          * former case, as we will generate no output. Since we still properly
6461          * report our exit code even when a pager is run, we _could_ run a
6462          * pager with --exit-code. But since we have not done so historically,
6463          * and because it is easy to find people oneline advising "git diff
6464          * --exit-code" in hooks and other scripts, we do not do so.
6465          */
6466         if (!opt->flags.exit_with_status &&
6467             check_pager_config("diff") != 0)
6468                 setup_pager();
6469 }