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