git.oblomov.eu Git - git/blob - diff.c

   1 /*
   2  * Copyright (C) 2005 Junio C Hamano
   3  */
   4 #include "cache.h"
   5 #include "config.h"
   6 #include "tempfile.h"
   7 #include "quote.h"
   8 #include "diff.h"
   9 #include "diffcore.h"
  10 #include "delta.h"
  11 #include "xdiff-interface.h"
  12 #include "color.h"
  13 #include "attr.h"
  14 #include "run-command.h"
  15 #include "utf8.h"
  16 #include "userdiff.h"
  17 #include "submodule-config.h"
  18 #include "submodule.h"
  19 #include "hashmap.h"
  20 #include "ll-merge.h"
  21 #include "string-list.h"
  22 #include "argv-array.h"
  23 #include "graph.h"
  24 #include "packfile.h"
  25
  26 #ifdef NO_FAST_WORKING_DIRECTORY
  27 #define FAST_WORKING_DIRECTORY 0
  28 #else
  29 #define FAST_WORKING_DIRECTORY 1
  30 #endif
  31
  32 static int diff_detect_rename_default;
  33 static int diff_indent_heuristic = 1;
  34 static int diff_rename_limit_default = 400;
  35 static int diff_suppress_blank_empty;
  36 static int diff_use_color_default = -1;
  37 static int diff_color_moved_default;
  38 static int diff_context_default = 3;
  39 static int diff_interhunk_context_default;
  40 static const char *diff_word_regex_cfg;
  41 static const char *external_diff_cmd_cfg;
  42 static const char *diff_order_file_cfg;
  43 int diff_auto_refresh_index = 1;
  44 static int diff_mnemonic_prefix;
  45 static int diff_no_prefix;
  46 static int diff_stat_graph_width;
  47 static int diff_dirstat_permille_default = 30;
  48 static struct diff_options default_diff_options;
  49 static long diff_algorithm;
  50 static unsigned ws_error_highlight_default = WSEH_NEW;
  51
  52 static char diff_colors[][COLOR_MAXLEN] = {
  53         GIT_COLOR_RESET,
  54         GIT_COLOR_NORMAL,       /* CONTEXT */
  55         GIT_COLOR_BOLD,         /* METAINFO */
  56         GIT_COLOR_CYAN,         /* FRAGINFO */
  57         GIT_COLOR_RED,          /* OLD */
  58         GIT_COLOR_GREEN,        /* NEW */
  59         GIT_COLOR_YELLOW,       /* COMMIT */
  60         GIT_COLOR_BG_RED,       /* WHITESPACE */
  61         GIT_COLOR_NORMAL,       /* FUNCINFO */
  62         GIT_COLOR_BOLD_MAGENTA, /* OLD_MOVED */
  63         GIT_COLOR_BOLD_BLUE,    /* OLD_MOVED ALTERNATIVE */
  64         GIT_COLOR_FAINT,        /* OLD_MOVED_DIM */
  65         GIT_COLOR_FAINT_ITALIC, /* OLD_MOVED_ALTERNATIVE_DIM */
  66         GIT_COLOR_BOLD_CYAN,    /* NEW_MOVED */
  67         GIT_COLOR_BOLD_YELLOW,  /* NEW_MOVED ALTERNATIVE */
  68         GIT_COLOR_FAINT,        /* NEW_MOVED_DIM */
  69         GIT_COLOR_FAINT_ITALIC, /* NEW_MOVED_ALTERNATIVE_DIM */
  70 };
  71
  72 static NORETURN void die_want_option(const char *option_name)
  73 {
  74         die(_("option '%s' requires a value"), option_name);
  75 }
  76
  77 static int parse_diff_color_slot(const char *var)
  78 {
  79         if (!strcasecmp(var, "context") || !strcasecmp(var, "plain"))
  80                 return DIFF_CONTEXT;
  81         if (!strcasecmp(var, "meta"))
  82                 return DIFF_METAINFO;
  83         if (!strcasecmp(var, "frag"))
  84                 return DIFF_FRAGINFO;
  85         if (!strcasecmp(var, "old"))
  86                 return DIFF_FILE_OLD;
  87         if (!strcasecmp(var, "new"))
  88                 return DIFF_FILE_NEW;
  89         if (!strcasecmp(var, "commit"))
  90                 return DIFF_COMMIT;
  91         if (!strcasecmp(var, "whitespace"))
  92                 return DIFF_WHITESPACE;
  93         if (!strcasecmp(var, "func"))
  94                 return DIFF_FUNCINFO;
  95         if (!strcasecmp(var, "oldmoved"))
  96                 return DIFF_FILE_OLD_MOVED;
  97         if (!strcasecmp(var, "oldmovedalternative"))
  98                 return DIFF_FILE_OLD_MOVED_ALT;
  99         if (!strcasecmp(var, "oldmoveddimmed"))
 100                 return DIFF_FILE_OLD_MOVED_DIM;
 101         if (!strcasecmp(var, "oldmovedalternativedimmed"))
 102                 return DIFF_FILE_OLD_MOVED_ALT_DIM;
 103         if (!strcasecmp(var, "newmoved"))
 104                 return DIFF_FILE_NEW_MOVED;
 105         if (!strcasecmp(var, "newmovedalternative"))
 106                 return DIFF_FILE_NEW_MOVED_ALT;
 107         if (!strcasecmp(var, "newmoveddimmed"))
 108                 return DIFF_FILE_NEW_MOVED_DIM;
 109         if (!strcasecmp(var, "newmovedalternativedimmed"))
 110                 return DIFF_FILE_NEW_MOVED_ALT_DIM;
 111         return -1;
 112 }
 113
 114 static int parse_dirstat_params(struct diff_options *options, const char *params_string,
 115                                 struct strbuf *errmsg)
 116 {
 117         char *params_copy = xstrdup(params_string);
 118         struct string_list params = STRING_LIST_INIT_NODUP;
 119         int ret = 0;
 120         int i;
 121
 122         if (*params_copy)
 123                 string_list_split_in_place(&params, params_copy, ',', -1);
 124         for (i = 0; i < params.nr; i++) {
 125                 const char *p = params.items[i].string;
 126                 if (!strcmp(p, "changes")) {
 127                         options->flags.dirstat_by_line = 0;
 128                         options->flags.dirstat_by_file = 0;
 129                 } else if (!strcmp(p, "lines")) {
 130                         options->flags.dirstat_by_line = 1;
 131                         options->flags.dirstat_by_file = 0;
 132                 } else if (!strcmp(p, "files")) {
 133                         options->flags.dirstat_by_line = 0;
 134                         options->flags.dirstat_by_file = 1;
 135                 } else if (!strcmp(p, "noncumulative")) {
 136                         options->flags.dirstat_cumulative = 0;
 137                 } else if (!strcmp(p, "cumulative")) {
 138                         options->flags.dirstat_cumulative = 1;
 139                 } else if (isdigit(*p)) {
 140                         char *end;
 141                         int permille = strtoul(p, &end, 10) * 10;
 142                         if (*end == '.' && isdigit(*++end)) {
 143                                 /* only use first digit */
 144                                 permille += *end - '0';
 145                                 /* .. and ignore any further digits */
 146                                 while (isdigit(*++end))
 147                                         ; /* nothing */
 148                         }
 149                         if (!*end)
 150                                 options->dirstat_permille = permille;
 151                         else {
 152                                 strbuf_addf(errmsg, _("  Failed to parse dirstat cut-off percentage '%s'\n"),
 153                                             p);
 154                                 ret++;
 155                         }
 156                 } else {
 157                         strbuf_addf(errmsg, _("  Unknown dirstat parameter '%s'\n"), p);
 158                         ret++;
 159                 }
 160
 161         }
 162         string_list_clear(&params, 0);
 163         free(params_copy);
 164         return ret;
 165 }
 166
 167 static int parse_submodule_params(struct diff_options *options, const char *value)
 168 {
 169         if (!strcmp(value, "log"))
 170                 options->submodule_format = DIFF_SUBMODULE_LOG;
 171         else if (!strcmp(value, "short"))
 172                 options->submodule_format = DIFF_SUBMODULE_SHORT;
 173         else if (!strcmp(value, "diff"))
 174                 options->submodule_format = DIFF_SUBMODULE_INLINE_DIFF;
 175         else
 176                 return -1;
 177         return 0;
 178 }
 179
 180 static int git_config_rename(const char *var, const char *value)
 181 {
 182         if (!value)
 183                 return DIFF_DETECT_RENAME;
 184         if (!strcasecmp(value, "copies") || !strcasecmp(value, "copy"))
 185                 return  DIFF_DETECT_COPY;
 186         return git_config_bool(var,value) ? DIFF_DETECT_RENAME : 0;
 187 }
 188
 189 long parse_algorithm_value(const char *value)
 190 {
 191         if (!value)
 192                 return -1;
 193         else if (!strcasecmp(value, "myers") || !strcasecmp(value, "default"))
 194                 return 0;
 195         else if (!strcasecmp(value, "minimal"))
 196                 return XDF_NEED_MINIMAL;
 197         else if (!strcasecmp(value, "patience"))
 198                 return XDF_PATIENCE_DIFF;
 199         else if (!strcasecmp(value, "histogram"))
 200                 return XDF_HISTOGRAM_DIFF;
 201         return -1;
 202 }
 203
 204 static int parse_one_token(const char **arg, const char *token)
 205 {
 206         const char *rest;
 207         if (skip_prefix(*arg, token, &rest) && (!*rest || *rest == ',')) {
 208                 *arg = rest;
 209                 return 1;
 210         }
 211         return 0;
 212 }
 213
 214 static int parse_ws_error_highlight(const char *arg)
 215 {
 216         const char *orig_arg = arg;
 217         unsigned val = 0;
 218
 219         while (*arg) {
 220                 if (parse_one_token(&arg, "none"))
 221                         val = 0;
 222                 else if (parse_one_token(&arg, "default"))
 223                         val = WSEH_NEW;
 224                 else if (parse_one_token(&arg, "all"))
 225                         val = WSEH_NEW | WSEH_OLD | WSEH_CONTEXT;
 226                 else if (parse_one_token(&arg, "new"))
 227                         val |= WSEH_NEW;
 228                 else if (parse_one_token(&arg, "old"))
 229                         val |= WSEH_OLD;
 230                 else if (parse_one_token(&arg, "context"))
 231                         val |= WSEH_CONTEXT;
 232                 else {
 233                         return -1 - (int)(arg - orig_arg);
 234                 }
 235                 if (*arg)
 236                         arg++;
 237         }
 238         return val;
 239 }
 240
 241 /*
 242  * These are to give UI layer defaults.
 243  * The core-level commands such as git-diff-files should
 244  * never be affected by the setting of diff.renames
 245  * the user happens to have in the configuration file.
 246  */
 247 void init_diff_ui_defaults(void)
 248 {
 249         diff_detect_rename_default = 1;
 250 }
 251
 252 int git_diff_heuristic_config(const char *var, const char *value, void *cb)
 253 {
 254         if (!strcmp(var, "diff.indentheuristic"))
 255                 diff_indent_heuristic = git_config_bool(var, value);
 256         return 0;
 257 }
 258
 259 static int parse_color_moved(const char *arg)
 260 {
 261         switch (git_parse_maybe_bool(arg)) {
 262         case 0:
 263                 return COLOR_MOVED_NO;
 264         case 1:
 265                 return COLOR_MOVED_DEFAULT;
 266         default:
 267                 break;
 268         }
 269
 270         if (!strcmp(arg, "no"))
 271                 return COLOR_MOVED_NO;
 272         else if (!strcmp(arg, "plain"))
 273                 return COLOR_MOVED_PLAIN;
 274         else if (!strcmp(arg, "zebra"))
 275                 return COLOR_MOVED_ZEBRA;
 276         else if (!strcmp(arg, "default"))
 277                 return COLOR_MOVED_DEFAULT;
 278         else if (!strcmp(arg, "dimmed_zebra"))
 279                 return COLOR_MOVED_ZEBRA_DIM;
 280         else
 281                 return error(_("color moved setting must be one of 'no', 'default', 'zebra', 'dimmed_zebra', 'plain'"));
 282 }
 283
 284 int git_diff_ui_config(const char *var, const char *value, void *cb)
 285 {
 286         if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 287                 diff_use_color_default = git_config_colorbool(var, value);
 288                 return 0;
 289         }
 290         if (!strcmp(var, "diff.colormoved")) {
 291                 int cm = parse_color_moved(value);
 292                 if (cm < 0)
 293                         return -1;
 294                 diff_color_moved_default = cm;
 295                 return 0;
 296         }
 297         if (!strcmp(var, "diff.context")) {
 298                 diff_context_default = git_config_int(var, value);
 299                 if (diff_context_default < 0)
 300                         return -1;
 301                 return 0;
 302         }
 303         if (!strcmp(var, "diff.interhunkcontext")) {
 304                 diff_interhunk_context_default = git_config_int(var, value);
 305                 if (diff_interhunk_context_default < 0)
 306                         return -1;
 307                 return 0;
 308         }
 309         if (!strcmp(var, "diff.renames")) {
 310                 diff_detect_rename_default = git_config_rename(var, value);
 311                 return 0;
 312         }
 313         if (!strcmp(var, "diff.autorefreshindex")) {
 314                 diff_auto_refresh_index = git_config_bool(var, value);
 315                 return 0;
 316         }
 317         if (!strcmp(var, "diff.mnemonicprefix")) {
 318                 diff_mnemonic_prefix = git_config_bool(var, value);
 319                 return 0;
 320         }
 321         if (!strcmp(var, "diff.noprefix")) {
 322                 diff_no_prefix = git_config_bool(var, value);
 323                 return 0;
 324         }
 325         if (!strcmp(var, "diff.statgraphwidth")) {
 326                 diff_stat_graph_width = git_config_int(var, value);
 327                 return 0;
 328         }
 329         if (!strcmp(var, "diff.external"))
 330                 return git_config_string(&external_diff_cmd_cfg, var, value);
 331         if (!strcmp(var, "diff.wordregex"))
 332                 return git_config_string(&diff_word_regex_cfg, var, value);
 333         if (!strcmp(var, "diff.orderfile"))
 334                 return git_config_pathname(&diff_order_file_cfg, var, value);
 335
 336         if (!strcmp(var, "diff.ignoresubmodules"))
 337                 handle_ignore_submodules_arg(&default_diff_options, value);
 338
 339         if (!strcmp(var, "diff.submodule")) {
 340                 if (parse_submodule_params(&default_diff_options, value))
 341                         warning(_("Unknown value for 'diff.submodule' config variable: '%s'"),
 342                                 value);
 343                 return 0;
 344         }
 345
 346         if (!strcmp(var, "diff.algorithm")) {
 347                 diff_algorithm = parse_algorithm_value(value);
 348                 if (diff_algorithm < 0)
 349                         return -1;
 350                 return 0;
 351         }
 352
 353         if (!strcmp(var, "diff.wserrorhighlight")) {
 354                 int val = parse_ws_error_highlight(value);
 355                 if (val < 0)
 356                         return -1;
 357                 ws_error_highlight_default = val;
 358                 return 0;
 359         }
 360
 361         if (git_color_config(var, value, cb) < 0)
 362                 return -1;
 363
 364         return git_diff_basic_config(var, value, cb);
 365 }
 366
 367 int git_diff_basic_config(const char *var, const char *value, void *cb)
 368 {
 369         const char *name;
 370
 371         if (!strcmp(var, "diff.renamelimit")) {
 372                 diff_rename_limit_default = git_config_int(var, value);
 373                 return 0;
 374         }
 375
 376         if (userdiff_config(var, value) < 0)
 377                 return -1;
 378
 379         if (skip_prefix(var, "diff.color.", &name) ||
 380             skip_prefix(var, "color.diff.", &name)) {
 381                 int slot = parse_diff_color_slot(name);
 382                 if (slot < 0)
 383                         return 0;
 384                 if (!value)
 385                         return config_error_nonbool(var);
 386                 return color_parse(value, diff_colors[slot]);
 387         }
 388
 389         /* like GNU diff's --suppress-blank-empty option  */
 390         if (!strcmp(var, "diff.suppressblankempty") ||
 391                         /* for backwards compatibility */
 392                         !strcmp(var, "diff.suppress-blank-empty")) {
 393                 diff_suppress_blank_empty = git_config_bool(var, value);
 394                 return 0;
 395         }
 396
 397         if (!strcmp(var, "diff.dirstat")) {
 398                 struct strbuf errmsg = STRBUF_INIT;
 399                 default_diff_options.dirstat_permille = diff_dirstat_permille_default;
 400                 if (parse_dirstat_params(&default_diff_options, value, &errmsg))
 401                         warning(_("Found errors in 'diff.dirstat' config variable:\n%s"),
 402                                 errmsg.buf);
 403                 strbuf_release(&errmsg);
 404                 diff_dirstat_permille_default = default_diff_options.dirstat_permille;
 405                 return 0;
 406         }
 407
 408         if (git_diff_heuristic_config(var, value, cb) < 0)
 409                 return -1;
 410
 411         return git_default_config(var, value, cb);
 412 }
 413
 414 static char *quote_two(const char *one, const char *two)
 415 {
 416         int need_one = quote_c_style(one, NULL, NULL, 1);
 417         int need_two = quote_c_style(two, NULL, NULL, 1);
 418         struct strbuf res = STRBUF_INIT;
 419
 420         if (need_one + need_two) {
 421                 strbuf_addch(&res, '"');
 422                 quote_c_style(one, &res, NULL, 1);
 423                 quote_c_style(two, &res, NULL, 1);
 424                 strbuf_addch(&res, '"');
 425         } else {
 426                 strbuf_addstr(&res, one);
 427                 strbuf_addstr(&res, two);
 428         }
 429         return strbuf_detach(&res, NULL);
 430 }
 431
 432 static const char *external_diff(void)
 433 {
 434         static const char *external_diff_cmd = NULL;
 435         static int done_preparing = 0;
 436
 437         if (done_preparing)
 438                 return external_diff_cmd;
 439         external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 440         if (!external_diff_cmd)
 441                 external_diff_cmd = external_diff_cmd_cfg;
 442         done_preparing = 1;
 443         return external_diff_cmd;
 444 }
 445
 446 /*
 447  * Keep track of files used for diffing. Sometimes such an entry
 448  * refers to a temporary file, sometimes to an existing file, and
 449  * sometimes to "/dev/null".
 450  */
 451 static struct diff_tempfile {
 452         /*
 453          * filename external diff should read from, or NULL if this
 454          * entry is currently not in use:
 455          */
 456         const char *name;
 457
 458         char hex[GIT_MAX_HEXSZ + 1];
 459         char mode[10];
 460
 461         /*
 462          * If this diff_tempfile instance refers to a temporary file,
 463          * this tempfile object is used to manage its lifetime.
 464          */
 465         struct tempfile *tempfile;
 466 } diff_temp[2];
 467
 468 struct emit_callback {
 469         int color_diff;
 470         unsigned ws_rule;
 471         int blank_at_eof_in_preimage;
 472         int blank_at_eof_in_postimage;
 473         int lno_in_preimage;
 474         int lno_in_postimage;
 475         const char **label_path;
 476         struct diff_words_data *diff_words;
 477         struct diff_options *opt;
 478         struct strbuf *header;
 479 };
 480
 481 static int count_lines(const char *data, int size)
 482 {
 483         int count, ch, completely_empty = 1, nl_just_seen = 0;
 484         count = 0;
 485         while (0 < size--) {
 486                 ch = *data++;
 487                 if (ch == '\n') {
 488                         count++;
 489                         nl_just_seen = 1;
 490                         completely_empty = 0;
 491                 }
 492                 else {
 493                         nl_just_seen = 0;
 494                         completely_empty = 0;
 495                 }
 496         }
 497         if (completely_empty)
 498                 return 0;
 499         if (!nl_just_seen)
 500                 count++; /* no trailing newline */
 501         return count;
 502 }
 503
 504 static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 505 {
 506         if (!DIFF_FILE_VALID(one)) {
 507                 mf->ptr = (char *)""; /* does not matter */
 508                 mf->size = 0;
 509                 return 0;
 510         }
 511         else if (diff_populate_filespec(one, 0))
 512                 return -1;
 513
 514         mf->ptr = one->data;
 515         mf->size = one->size;
 516         return 0;
 517 }
 518
 519 /* like fill_mmfile, but only for size, so we can avoid retrieving blob */
 520 static unsigned long diff_filespec_size(struct diff_filespec *one)
 521 {
 522         if (!DIFF_FILE_VALID(one))
 523                 return 0;
 524         diff_populate_filespec(one, CHECK_SIZE_ONLY);
 525         return one->size;
 526 }
 527
 528 static int count_trailing_blank(mmfile_t *mf, unsigned ws_rule)
 529 {
 530         char *ptr = mf->ptr;
 531         long size = mf->size;
 532         int cnt = 0;
 533
 534         if (!size)
 535                 return cnt;
 536         ptr += size - 1; /* pointing at the very end */
 537         if (*ptr != '\n')
 538                 ; /* incomplete line */
 539         else
 540                 ptr--; /* skip the last LF */
 541         while (mf->ptr < ptr) {
 542                 char *prev_eol;
 543                 for (prev_eol = ptr; mf->ptr <= prev_eol; prev_eol--)
 544                         if (*prev_eol == '\n')
 545                                 break;
 546                 if (!ws_blank_line(prev_eol + 1, ptr - prev_eol, ws_rule))
 547                         break;
 548                 cnt++;
 549                 ptr = prev_eol - 1;
 550         }
 551         return cnt;
 552 }
 553
 554 static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
 555                                struct emit_callback *ecbdata)
 556 {
 557         int l1, l2, at;
 558         unsigned ws_rule = ecbdata->ws_rule;
 559         l1 = count_trailing_blank(mf1, ws_rule);
 560         l2 = count_trailing_blank(mf2, ws_rule);
 561         if (l2 <= l1) {
 562                 ecbdata->blank_at_eof_in_preimage = 0;
 563                 ecbdata->blank_at_eof_in_postimage = 0;
 564                 return;
 565         }
 566         at = count_lines(mf1->ptr, mf1->size);
 567         ecbdata->blank_at_eof_in_preimage = (at - l1) + 1;
 568
 569         at = count_lines(mf2->ptr, mf2->size);
 570         ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
 571 }
 572
 573 static void emit_line_0(struct diff_options *o, const char *set, const char *reset,
 574                         int first, const char *line, int len)
 575 {
 576         int has_trailing_newline, has_trailing_carriage_return;
 577         int nofirst;
 578         FILE *file = o->file;
 579
 580         fputs(diff_line_prefix(o), file);
 581
 582         if (len == 0) {
 583                 has_trailing_newline = (first == '\n');
 584                 has_trailing_carriage_return = (!has_trailing_newline &&
 585                                                 (first == '\r'));
 586                 nofirst = has_trailing_newline || has_trailing_carriage_return;
 587         } else {
 588                 has_trailing_newline = (len > 0 && line[len-1] == '\n');
 589                 if (has_trailing_newline)
 590                         len--;
 591                 has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
 592                 if (has_trailing_carriage_return)
 593                         len--;
 594                 nofirst = 0;
 595         }
 596
 597         if (len || !nofirst) {
 598                 fputs(set, file);
 599                 if (!nofirst)
 600                         fputc(first, file);
 601                 fwrite(line, len, 1, file);
 602                 fputs(reset, file);
 603         }
 604         if (has_trailing_carriage_return)
 605                 fputc('\r', file);
 606         if (has_trailing_newline)
 607                 fputc('\n', file);
 608 }
 609
 610 static void emit_line(struct diff_options *o, const char *set, const char *reset,
 611                       const char *line, int len)
 612 {
 613         emit_line_0(o, set, reset, line[0], line+1, len-1);
 614 }
 615
 616 enum diff_symbol {
 617         DIFF_SYMBOL_BINARY_DIFF_HEADER,
 618         DIFF_SYMBOL_BINARY_DIFF_HEADER_DELTA,
 619         DIFF_SYMBOL_BINARY_DIFF_HEADER_LITERAL,
 620         DIFF_SYMBOL_BINARY_DIFF_BODY,
 621         DIFF_SYMBOL_BINARY_DIFF_FOOTER,
 622         DIFF_SYMBOL_STATS_SUMMARY_NO_FILES,
 623         DIFF_SYMBOL_STATS_SUMMARY_ABBREV,
 624         DIFF_SYMBOL_STATS_SUMMARY_INSERTS_DELETES,
 625         DIFF_SYMBOL_STATS_LINE,
 626         DIFF_SYMBOL_WORD_DIFF,
 627         DIFF_SYMBOL_STAT_SEP,
 628         DIFF_SYMBOL_SUMMARY,
 629         DIFF_SYMBOL_SUBMODULE_ADD,
 630         DIFF_SYMBOL_SUBMODULE_DEL,
 631         DIFF_SYMBOL_SUBMODULE_UNTRACKED,
 632         DIFF_SYMBOL_SUBMODULE_MODIFIED,
 633         DIFF_SYMBOL_SUBMODULE_HEADER,
 634         DIFF_SYMBOL_SUBMODULE_ERROR,
 635         DIFF_SYMBOL_SUBMODULE_PIPETHROUGH,
 636         DIFF_SYMBOL_REWRITE_DIFF,
 637         DIFF_SYMBOL_BINARY_FILES,
 638         DIFF_SYMBOL_HEADER,
 639         DIFF_SYMBOL_FILEPAIR_PLUS,
 640         DIFF_SYMBOL_FILEPAIR_MINUS,
 641         DIFF_SYMBOL_WORDS_PORCELAIN,
 642         DIFF_SYMBOL_WORDS,
 643         DIFF_SYMBOL_CONTEXT,
 644         DIFF_SYMBOL_CONTEXT_INCOMPLETE,
 645         DIFF_SYMBOL_PLUS,
 646         DIFF_SYMBOL_MINUS,
 647         DIFF_SYMBOL_NO_LF_EOF,
 648         DIFF_SYMBOL_CONTEXT_FRAGINFO,
 649         DIFF_SYMBOL_CONTEXT_MARKER,
 650         DIFF_SYMBOL_SEPARATOR
 651 };
 652 /*
 653  * Flags for content lines:
 654  * 0..12 are whitespace rules
 655  * 13-15 are WSEH_NEW | WSEH_OLD | WSEH_CONTEXT
 656  * 16 is marking if the line is blank at EOF
 657  */
 658 #define DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF      (1<<16)
 659 #define DIFF_SYMBOL_MOVED_LINE                  (1<<17)
 660 #define DIFF_SYMBOL_MOVED_LINE_ALT              (1<<18)
 661 #define DIFF_SYMBOL_MOVED_LINE_UNINTERESTING    (1<<19)
 662 #define DIFF_SYMBOL_CONTENT_WS_MASK (WSEH_NEW | WSEH_OLD | WSEH_CONTEXT | WS_RULE_MASK)
 663
 664 /*
 665  * This struct is used when we need to buffer the output of the diff output.
 666  *
 667  * NEEDSWORK: Instead of storing a copy of the line, add an offset pointer
 668  * into the pre/post image file. This pointer could be a union with the
 669  * line pointer. By storing an offset into the file instead of the literal line,
 670  * we can decrease the memory footprint for the buffered output. At first we
 671  * may want to only have indirection for the content lines, but we could also
 672  * enhance the state for emitting prefabricated lines, e.g. the similarity
 673  * score line or hunk/file headers would only need to store a number or path
 674  * and then the output can be constructed later on depending on state.
 675  */
 676 struct emitted_diff_symbol {
 677         const char *line;
 678         int len;
 679         int flags;
 680         enum diff_symbol s;
 681 };
 682 #define EMITTED_DIFF_SYMBOL_INIT {NULL}
 683
 684 struct emitted_diff_symbols {
 685         struct emitted_diff_symbol *buf;
 686         int nr, alloc;
 687 };
 688 #define EMITTED_DIFF_SYMBOLS_INIT {NULL, 0, 0}
 689
 690 static void append_emitted_diff_symbol(struct diff_options *o,
 691                                        struct emitted_diff_symbol *e)
 692 {
 693         struct emitted_diff_symbol *f;
 694
 695         ALLOC_GROW(o->emitted_symbols->buf,
 696                    o->emitted_symbols->nr + 1,
 697                    o->emitted_symbols->alloc);
 698         f = &o->emitted_symbols->buf[o->emitted_symbols->nr++];
 699
 700         memcpy(f, e, sizeof(struct emitted_diff_symbol));
 701         f->line = e->line ? xmemdupz(e->line, e->len) : NULL;
 702 }
 703
 704 struct moved_entry {
 705         struct hashmap_entry ent;
 706         const struct emitted_diff_symbol *es;
 707         struct moved_entry *next_line;
 708 };
 709
 710 static int moved_entry_cmp(const struct diff_options *diffopt,
 711                            const struct moved_entry *a,
 712                            const struct moved_entry *b,
 713                            const void *keydata)
 714 {
 715         return !xdiff_compare_lines(a->es->line, a->es->len,
 716                                     b->es->line, b->es->len,
 717                                     diffopt->xdl_opts);
 718 }
 719
 720 static struct moved_entry *prepare_entry(struct diff_options *o,
 721                                          int line_no)
 722 {
 723         struct moved_entry *ret = xmalloc(sizeof(*ret));
 724         struct emitted_diff_symbol *l = &o->emitted_symbols->buf[line_no];
 725
 726         ret->ent.hash = xdiff_hash_string(l->line, l->len, o->xdl_opts);
 727         ret->es = l;
 728         ret->next_line = NULL;
 729
 730         return ret;
 731 }
 732
 733 static void add_lines_to_move_detection(struct diff_options *o,
 734                                         struct hashmap *add_lines,
 735                                         struct hashmap *del_lines)
 736 {
 737         struct moved_entry *prev_line = NULL;
 738
 739         int n;
 740         for (n = 0; n < o->emitted_symbols->nr; n++) {
 741                 struct hashmap *hm;
 742                 struct moved_entry *key;
 743
 744                 switch (o->emitted_symbols->buf[n].s) {
 745                 case DIFF_SYMBOL_PLUS:
 746                         hm = add_lines;
 747                         break;
 748                 case DIFF_SYMBOL_MINUS:
 749                         hm = del_lines;
 750                         break;
 751                 default:
 752                         prev_line = NULL;
 753                         continue;
 754                 }
 755
 756                 key = prepare_entry(o, n);
 757                 if (prev_line && prev_line->es->s == o->emitted_symbols->buf[n].s)
 758                         prev_line->next_line = key;
 759
 760                 hashmap_add(hm, key);
 761                 prev_line = key;
 762         }
 763 }
 764
 765 static int shrink_potential_moved_blocks(struct moved_entry **pmb,
 766                                          int pmb_nr)
 767 {
 768         int lp, rp;
 769
 770         /* Shrink the set of potential block to the remaining running */
 771         for (lp = 0, rp = pmb_nr - 1; lp <= rp;) {
 772                 while (lp < pmb_nr && pmb[lp])
 773                         lp++;
 774                 /* lp points at the first NULL now */
 775
 776                 while (rp > -1 && !pmb[rp])
 777                         rp--;
 778                 /* rp points at the last non-NULL */
 779
 780                 if (lp < pmb_nr && rp > -1 && lp < rp) {
 781                         pmb[lp] = pmb[rp];
 782                         pmb[rp] = NULL;
 783                         rp--;
 784                         lp++;
 785                 }
 786         }
 787
 788         /* Remember the number of running sets */
 789         return rp + 1;
 790 }
 791
 792 /*
 793  * If o->color_moved is COLOR_MOVED_PLAIN, this function does nothing.
 794  *
 795  * Otherwise, if the last block has fewer alphanumeric characters than
 796  * COLOR_MOVED_MIN_ALNUM_COUNT, unset DIFF_SYMBOL_MOVED_LINE on all lines in
 797  * that block.
 798  *
 799  * The last block consists of the (n - block_length)'th line up to but not
 800  * including the nth line.
 801  *
 802  * NEEDSWORK: This uses the same heuristic as blame_entry_score() in blame.c.
 803  * Think of a way to unify them.
 804  */
 805 static void adjust_last_block(struct diff_options *o, int n, int block_length)
 806 {
 807         int i, alnum_count = 0;
 808         if (o->color_moved == COLOR_MOVED_PLAIN)
 809                 return;
 810         for (i = 1; i < block_length + 1; i++) {
 811                 const char *c = o->emitted_symbols->buf[n - i].line;
 812                 for (; *c; c++) {
 813                         if (!isalnum(*c))
 814                                 continue;
 815                         alnum_count++;
 816                         if (alnum_count >= COLOR_MOVED_MIN_ALNUM_COUNT)
 817                                 return;
 818                 }
 819         }
 820         for (i = 1; i < block_length + 1; i++)
 821                 o->emitted_symbols->buf[n - i].flags &= ~DIFF_SYMBOL_MOVED_LINE;
 822 }
 823
 824 /* Find blocks of moved code, delegate actual coloring decision to helper */
 825 static void mark_color_as_moved(struct diff_options *o,
 826                                 struct hashmap *add_lines,
 827                                 struct hashmap *del_lines)
 828 {
 829         struct moved_entry **pmb = NULL; /* potentially moved blocks */
 830         int pmb_nr = 0, pmb_alloc = 0;
 831         int n, flipped_block = 1, block_length = 0;
 832
 833
 834         for (n = 0; n < o->emitted_symbols->nr; n++) {
 835                 struct hashmap *hm = NULL;
 836                 struct moved_entry *key;
 837                 struct moved_entry *match = NULL;
 838                 struct emitted_diff_symbol *l = &o->emitted_symbols->buf[n];
 839                 int i;
 840
 841                 switch (l->s) {
 842                 case DIFF_SYMBOL_PLUS:
 843                         hm = del_lines;
 844                         key = prepare_entry(o, n);
 845                         match = hashmap_get(hm, key, o);
 846                         free(key);
 847                         break;
 848                 case DIFF_SYMBOL_MINUS:
 849                         hm = add_lines;
 850                         key = prepare_entry(o, n);
 851                         match = hashmap_get(hm, key, o);
 852                         free(key);
 853                         break;
 854                 default:
 855                         flipped_block = 1;
 856                 }
 857
 858                 if (!match) {
 859                         adjust_last_block(o, n, block_length);
 860                         pmb_nr = 0;
 861                         block_length = 0;
 862                         continue;
 863                 }
 864
 865                 l->flags |= DIFF_SYMBOL_MOVED_LINE;
 866
 867                 if (o->color_moved == COLOR_MOVED_PLAIN)
 868                         continue;
 869
 870                 /* Check any potential block runs, advance each or nullify */
 871                 for (i = 0; i < pmb_nr; i++) {
 872                         struct moved_entry *p = pmb[i];
 873                         struct moved_entry *pnext = (p && p->next_line) ?
 874                                         p->next_line : NULL;
 875                         if (pnext && !hm->cmpfn(o, pnext, match, NULL)) {
 876                                 pmb[i] = p->next_line;
 877                         } else {
 878                                 pmb[i] = NULL;
 879                         }
 880                 }
 881
 882                 pmb_nr = shrink_potential_moved_blocks(pmb, pmb_nr);
 883
 884                 if (pmb_nr == 0) {
 885                         /*
 886                          * The current line is the start of a new block.
 887                          * Setup the set of potential blocks.
 888                          */
 889                         for (; match; match = hashmap_get_next(hm, match)) {
 890                                 ALLOC_GROW(pmb, pmb_nr + 1, pmb_alloc);
 891                                 pmb[pmb_nr++] = match;
 892                         }
 893
 894                         flipped_block = (flipped_block + 1) % 2;
 895
 896                         adjust_last_block(o, n, block_length);
 897                         block_length = 0;
 898                 }
 899
 900                 block_length++;
 901
 902                 if (flipped_block)
 903                         l->flags |= DIFF_SYMBOL_MOVED_LINE_ALT;
 904         }
 905         adjust_last_block(o, n, block_length);
 906
 907         free(pmb);
 908 }
 909
 910 #define DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK \
 911   (DIFF_SYMBOL_MOVED_LINE | DIFF_SYMBOL_MOVED_LINE_ALT)
 912 static void dim_moved_lines(struct diff_options *o)
 913 {
 914         int n;
 915         for (n = 0; n < o->emitted_symbols->nr; n++) {
 916                 struct emitted_diff_symbol *prev = (n != 0) ?
 917                                 &o->emitted_symbols->buf[n - 1] : NULL;
 918                 struct emitted_diff_symbol *l = &o->emitted_symbols->buf[n];
 919                 struct emitted_diff_symbol *next =
 920                                 (n < o->emitted_symbols->nr - 1) ?
 921                                 &o->emitted_symbols->buf[n + 1] : NULL;
 922
 923                 /* Not a plus or minus line? */
 924                 if (l->s != DIFF_SYMBOL_PLUS && l->s != DIFF_SYMBOL_MINUS)
 925                         continue;
 926
 927                 /* Not a moved line? */
 928                 if (!(l->flags & DIFF_SYMBOL_MOVED_LINE))
 929                         continue;
 930
 931                 /*
 932                  * If prev or next are not a plus or minus line,
 933                  * pretend they don't exist
 934                  */
 935                 if (prev && prev->s != DIFF_SYMBOL_PLUS &&
 936                             prev->s != DIFF_SYMBOL_MINUS)
 937                         prev = NULL;
 938                 if (next && next->s != DIFF_SYMBOL_PLUS &&
 939                             next->s != DIFF_SYMBOL_MINUS)
 940                         next = NULL;
 941
 942                 /* Inside a block? */
 943                 if ((prev &&
 944                     (prev->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK) ==
 945                     (l->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK)) &&
 946                     (next &&
 947                     (next->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK) ==
 948                     (l->flags & DIFF_SYMBOL_MOVED_LINE_ZEBRA_MASK))) {
 949                         l->flags |= DIFF_SYMBOL_MOVED_LINE_UNINTERESTING;
 950                         continue;
 951                 }
 952
 953                 /* Check if we are at an interesting bound: */
 954                 if (prev && (prev->flags & DIFF_SYMBOL_MOVED_LINE) &&
 955                     (prev->flags & DIFF_SYMBOL_MOVED_LINE_ALT) !=
 956                        (l->flags & DIFF_SYMBOL_MOVED_LINE_ALT))
 957                         continue;
 958                 if (next && (next->flags & DIFF_SYMBOL_MOVED_LINE) &&
 959                     (next->flags & DIFF_SYMBOL_MOVED_LINE_ALT) !=
 960                        (l->flags & DIFF_SYMBOL_MOVED_LINE_ALT))
 961                         continue;
 962
 963                 /*
 964                  * The boundary to prev and next are not interesting,
 965                  * so this line is not interesting as a whole
 966                  */
 967                 l->flags |= DIFF_SYMBOL_MOVED_LINE_UNINTERESTING;
 968         }
 969 }
 970
 971 static void emit_line_ws_markup(struct diff_options *o,
 972                                 const char *set, const char *reset,
 973                                 const char *line, int len, char sign,
 974                                 unsigned ws_rule, int blank_at_eof)
 975 {
 976         const char *ws = NULL;
 977
 978         if (o->ws_error_highlight & ws_rule) {
 979                 ws = diff_get_color_opt(o, DIFF_WHITESPACE);
 980                 if (!*ws)
 981                         ws = NULL;
 982         }
 983
 984         if (!ws)
 985                 emit_line_0(o, set, reset, sign, line, len);
 986         else if (blank_at_eof)
 987                 /* Blank line at EOF - paint '+' as well */
 988                 emit_line_0(o, ws, reset, sign, line, len);
 989         else {
 990                 /* Emit just the prefix, then the rest. */
 991                 emit_line_0(o, set, reset, sign, "", 0);
 992                 ws_check_emit(line, len, ws_rule,
 993                               o->file, set, reset, ws);
 994         }
 995 }
 996
 997 static void emit_diff_symbol_from_struct(struct diff_options *o,
 998                                          struct emitted_diff_symbol *eds)
 999 {
1000         static const char *nneof = " No newline at end of file\n";
1001         const char *context, *reset, *set, *meta, *fraginfo;
1002         struct strbuf sb = STRBUF_INIT;
1003
1004         enum diff_symbol s = eds->s;
1005         const char *line = eds->line;
1006         int len = eds->len;
1007         unsigned flags = eds->flags;
1008
1009         switch (s) {
1010         case DIFF_SYMBOL_NO_LF_EOF:
1011                 context = diff_get_color_opt(o, DIFF_CONTEXT);
1012                 reset = diff_get_color_opt(o, DIFF_RESET);
1013                 putc('\n', o->file);
1014                 emit_line_0(o, context, reset, '\\',
1015                             nneof, strlen(nneof));
1016                 break;
1017         case DIFF_SYMBOL_SUBMODULE_HEADER:
1018         case DIFF_SYMBOL_SUBMODULE_ERROR:
1019         case DIFF_SYMBOL_SUBMODULE_PIPETHROUGH:
1020         case DIFF_SYMBOL_STATS_SUMMARY_INSERTS_DELETES:
1021         case DIFF_SYMBOL_SUMMARY:
1022         case DIFF_SYMBOL_STATS_LINE:
1023         case DIFF_SYMBOL_BINARY_DIFF_BODY:
1024         case DIFF_SYMBOL_CONTEXT_FRAGINFO:
1025                 emit_line(o, "", "", line, len);
1026                 break;
1027         case DIFF_SYMBOL_CONTEXT_INCOMPLETE:
1028         case DIFF_SYMBOL_CONTEXT_MARKER:
1029                 context = diff_get_color_opt(o, DIFF_CONTEXT);
1030                 reset = diff_get_color_opt(o, DIFF_RESET);
1031                 emit_line(o, context, reset, line, len);
1032                 break;
1033         case DIFF_SYMBOL_SEPARATOR:
1034                 fprintf(o->file, "%s%c",
1035                         diff_line_prefix(o),
1036                         o->line_termination);
1037                 break;
1038         case DIFF_SYMBOL_CONTEXT:
1039                 set = diff_get_color_opt(o, DIFF_CONTEXT);
1040                 reset = diff_get_color_opt(o, DIFF_RESET);
1041                 emit_line_ws_markup(o, set, reset, line, len, ' ',
1042                                     flags & (DIFF_SYMBOL_CONTENT_WS_MASK), 0);
1043                 break;
1044         case DIFF_SYMBOL_PLUS:
1045                 switch (flags & (DIFF_SYMBOL_MOVED_LINE |
1046                                  DIFF_SYMBOL_MOVED_LINE_ALT |
1047                                  DIFF_SYMBOL_MOVED_LINE_UNINTERESTING)) {
1048                 case DIFF_SYMBOL_MOVED_LINE |
1049                      DIFF_SYMBOL_MOVED_LINE_ALT |
1050                      DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1051                         set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED_ALT_DIM);
1052                         break;
1053                 case DIFF_SYMBOL_MOVED_LINE |
1054                      DIFF_SYMBOL_MOVED_LINE_ALT:
1055                         set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED_ALT);
1056                         break;
1057                 case DIFF_SYMBOL_MOVED_LINE |
1058                      DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1059                         set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED_DIM);
1060                         break;
1061                 case DIFF_SYMBOL_MOVED_LINE:
1062                         set = diff_get_color_opt(o, DIFF_FILE_NEW_MOVED);
1063                         break;
1064                 default:
1065                         set = diff_get_color_opt(o, DIFF_FILE_NEW);
1066                 }
1067                 reset = diff_get_color_opt(o, DIFF_RESET);
1068                 emit_line_ws_markup(o, set, reset, line, len, '+',
1069                                     flags & DIFF_SYMBOL_CONTENT_WS_MASK,
1070                                     flags & DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF);
1071                 break;
1072         case DIFF_SYMBOL_MINUS:
1073                 switch (flags & (DIFF_SYMBOL_MOVED_LINE |
1074                                  DIFF_SYMBOL_MOVED_LINE_ALT |
1075                                  DIFF_SYMBOL_MOVED_LINE_UNINTERESTING)) {
1076                 case DIFF_SYMBOL_MOVED_LINE |
1077                      DIFF_SYMBOL_MOVED_LINE_ALT |
1078                      DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1079                         set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED_ALT_DIM);
1080                         break;
1081                 case DIFF_SYMBOL_MOVED_LINE |
1082                      DIFF_SYMBOL_MOVED_LINE_ALT:
1083                         set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED_ALT);
1084                         break;
1085                 case DIFF_SYMBOL_MOVED_LINE |
1086                      DIFF_SYMBOL_MOVED_LINE_UNINTERESTING:
1087                         set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED_DIM);
1088                         break;
1089                 case DIFF_SYMBOL_MOVED_LINE:
1090                         set = diff_get_color_opt(o, DIFF_FILE_OLD_MOVED);
1091                         break;
1092                 default:
1093                         set = diff_get_color_opt(o, DIFF_FILE_OLD);
1094                 }
1095                 reset = diff_get_color_opt(o, DIFF_RESET);
1096                 emit_line_ws_markup(o, set, reset, line, len, '-',
1097                                     flags & DIFF_SYMBOL_CONTENT_WS_MASK, 0);
1098                 break;
1099         case DIFF_SYMBOL_WORDS_PORCELAIN:
1100                 context = diff_get_color_opt(o, DIFF_CONTEXT);
1101                 reset = diff_get_color_opt(o, DIFF_RESET);
1102                 emit_line(o, context, reset, line, len);
1103                 fputs("~\n", o->file);
1104                 break;
1105         case DIFF_SYMBOL_WORDS:
1106                 context = diff_get_color_opt(o, DIFF_CONTEXT);
1107                 reset = diff_get_color_opt(o, DIFF_RESET);
1108                 /*
1109                  * Skip the prefix character, if any.  With
1110                  * diff_suppress_blank_empty, there may be
1111                  * none.
1112                  */
1113                 if (line[0] != '\n') {
1114                         line++;
1115                         len--;
1116                 }
1117                 emit_line(o, context, reset, line, len);
1118                 break;
1119         case DIFF_SYMBOL_FILEPAIR_PLUS:
1120                 meta = diff_get_color_opt(o, DIFF_METAINFO);
1121                 reset = diff_get_color_opt(o, DIFF_RESET);
1122                 fprintf(o->file, "%s%s+++ %s%s%s\n", diff_line_prefix(o), meta,
1123                         line, reset,
1124                         strchr(line, ' ') ? "\t" : "");
1125                 break;
1126         case DIFF_SYMBOL_FILEPAIR_MINUS:
1127                 meta = diff_get_color_opt(o, DIFF_METAINFO);
1128                 reset = diff_get_color_opt(o, DIFF_RESET);
1129                 fprintf(o->file, "%s%s--- %s%s%s\n", diff_line_prefix(o), meta,
1130                         line, reset,
1131                         strchr(line, ' ') ? "\t" : "");
1132                 break;
1133         case DIFF_SYMBOL_BINARY_FILES:
1134         case DIFF_SYMBOL_HEADER:
1135                 fprintf(o->file, "%s", line);
1136                 break;
1137         case DIFF_SYMBOL_BINARY_DIFF_HEADER:
1138                 fprintf(o->file, "%sGIT binary patch\n", diff_line_prefix(o));
1139                 break;
1140         case DIFF_SYMBOL_BINARY_DIFF_HEADER_DELTA:
1141                 fprintf(o->file, "%sdelta %s\n", diff_line_prefix(o), line);
1142                 break;
1143         case DIFF_SYMBOL_BINARY_DIFF_HEADER_LITERAL:
1144                 fprintf(o->file, "%sliteral %s\n", diff_line_prefix(o), line);
1145                 break;
1146         case DIFF_SYMBOL_BINARY_DIFF_FOOTER:
1147                 fputs(diff_line_prefix(o), o->file);
1148                 fputc('\n', o->file);
1149                 break;
1150         case DIFF_SYMBOL_REWRITE_DIFF:
1151                 fraginfo = diff_get_color(o->use_color, DIFF_FRAGINFO);
1152                 reset = diff_get_color_opt(o, DIFF_RESET);
1153                 emit_line(o, fraginfo, reset, line, len);
1154                 break;
1155         case DIFF_SYMBOL_SUBMODULE_ADD:
1156                 set = diff_get_color_opt(o, DIFF_FILE_NEW);
1157                 reset = diff_get_color_opt(o, DIFF_RESET);
1158                 emit_line(o, set, reset, line, len);
1159                 break;
1160         case DIFF_SYMBOL_SUBMODULE_DEL:
1161                 set = diff_get_color_opt(o, DIFF_FILE_OLD);
1162                 reset = diff_get_color_opt(o, DIFF_RESET);
1163                 emit_line(o, set, reset, line, len);
1164                 break;
1165         case DIFF_SYMBOL_SUBMODULE_UNTRACKED:
1166                 fprintf(o->file, "%sSubmodule %s contains untracked content\n",
1167                         diff_line_prefix(o), line);
1168                 break;
1169         case DIFF_SYMBOL_SUBMODULE_MODIFIED:
1170                 fprintf(o->file, "%sSubmodule %s contains modified content\n",
1171                         diff_line_prefix(o), line);
1172                 break;
1173         case DIFF_SYMBOL_STATS_SUMMARY_NO_FILES:
1174                 emit_line(o, "", "", " 0 files changed\n",
1175                           strlen(" 0 files changed\n"));
1176                 break;
1177         case DIFF_SYMBOL_STATS_SUMMARY_ABBREV:
1178                 emit_line(o, "", "", " ...\n", strlen(" ...\n"));
1179                 break;
1180         case DIFF_SYMBOL_WORD_DIFF:
1181                 fprintf(o->file, "%.*s", len, line);
1182                 break;
1183         case DIFF_SYMBOL_STAT_SEP:
1184                 fputs(o->stat_sep, o->file);
1185                 break;
1186         default:
1187                 die("BUG: unknown diff symbol");
1188         }
1189         strbuf_release(&sb);
1190 }
1191
1192 static void emit_diff_symbol(struct diff_options *o, enum diff_symbol s,
1193                              const char *line, int len, unsigned flags)
1194 {
1195         struct emitted_diff_symbol e = {line, len, flags, s};
1196
1197         if (o->emitted_symbols)
1198                 append_emitted_diff_symbol(o, &e);
1199         else
1200                 emit_diff_symbol_from_struct(o, &e);
1201 }
1202
1203 void diff_emit_submodule_del(struct diff_options *o, const char *line)
1204 {
1205         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_DEL, line, strlen(line), 0);
1206 }
1207
1208 void diff_emit_submodule_add(struct diff_options *o, const char *line)
1209 {
1210         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_ADD, line, strlen(line), 0);
1211 }
1212
1213 void diff_emit_submodule_untracked(struct diff_options *o, const char *path)
1214 {
1215         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_UNTRACKED,
1216                          path, strlen(path), 0);
1217 }
1218
1219 void diff_emit_submodule_modified(struct diff_options *o, const char *path)
1220 {
1221         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_MODIFIED,
1222                          path, strlen(path), 0);
1223 }
1224
1225 void diff_emit_submodule_header(struct diff_options *o, const char *header)
1226 {
1227         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_HEADER,
1228                          header, strlen(header), 0);
1229 }
1230
1231 void diff_emit_submodule_error(struct diff_options *o, const char *err)
1232 {
1233         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_ERROR, err, strlen(err), 0);
1234 }
1235
1236 void diff_emit_submodule_pipethrough(struct diff_options *o,
1237                                      const char *line, int len)
1238 {
1239         emit_diff_symbol(o, DIFF_SYMBOL_SUBMODULE_PIPETHROUGH, line, len, 0);
1240 }
1241
1242 static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
1243 {
1244         if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
1245               ecbdata->blank_at_eof_in_preimage &&
1246               ecbdata->blank_at_eof_in_postimage &&
1247               ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
1248               ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
1249                 return 0;
1250         return ws_blank_line(line, len, ecbdata->ws_rule);
1251 }
1252
1253 static void emit_add_line(const char *reset,
1254                           struct emit_callback *ecbdata,
1255                           const char *line, int len)
1256 {
1257         unsigned flags = WSEH_NEW | ecbdata->ws_rule;
1258         if (new_blank_line_at_eof(ecbdata, line, len))
1259                 flags |= DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF;
1260
1261         emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_PLUS, line, len, flags);
1262 }
1263
1264 static void emit_del_line(const char *reset,
1265                           struct emit_callback *ecbdata,
1266                           const char *line, int len)
1267 {
1268         unsigned flags = WSEH_OLD | ecbdata->ws_rule;
1269         emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_MINUS, line, len, flags);
1270 }
1271
1272 static void emit_context_line(const char *reset,
1273                               struct emit_callback *ecbdata,
1274                               const char *line, int len)
1275 {
1276         unsigned flags = WSEH_CONTEXT | ecbdata->ws_rule;
1277         emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_CONTEXT, line, len, flags);
1278 }
1279
1280 static void emit_hunk_header(struct emit_callback *ecbdata,
1281                              const char *line, int len)
1282 {
1283         const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
1284         const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
1285         const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
1286         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1287         static const char atat[2] = { '@', '@' };
1288         const char *cp, *ep;
1289         struct strbuf msgbuf = STRBUF_INIT;
1290         int org_len = len;
1291         int i = 1;
1292
1293         /*
1294          * As a hunk header must begin with "@@ -<old>, +<new> @@",
1295          * it always is at least 10 bytes long.
1296          */
1297         if (len < 10 ||
1298             memcmp(line, atat, 2) ||
1299             !(ep = memmem(line + 2, len - 2, atat, 2))) {
1300                 emit_diff_symbol(ecbdata->opt,
1301                                  DIFF_SYMBOL_CONTEXT_MARKER, line, len, 0);
1302                 return;
1303         }
1304         ep += 2; /* skip over @@ */
1305
1306         /* The hunk header in fraginfo color */
1307         strbuf_addstr(&msgbuf, frag);
1308         strbuf_add(&msgbuf, line, ep - line);
1309         strbuf_addstr(&msgbuf, reset);
1310
1311         /*
1312          * trailing "\r\n"
1313          */
1314         for ( ; i < 3; i++)
1315                 if (line[len - i] == '\r' || line[len - i] == '\n')
1316                         len--;
1317
1318         /* blank before the func header */
1319         for (cp = ep; ep - line < len; ep++)
1320                 if (*ep != ' ' && *ep != '\t')
1321                         break;
1322         if (ep != cp) {
1323                 strbuf_addstr(&msgbuf, context);
1324                 strbuf_add(&msgbuf, cp, ep - cp);
1325                 strbuf_addstr(&msgbuf, reset);
1326         }
1327
1328         if (ep < line + len) {
1329                 strbuf_addstr(&msgbuf, func);
1330                 strbuf_add(&msgbuf, ep, line + len - ep);
1331                 strbuf_addstr(&msgbuf, reset);
1332         }
1333
1334         strbuf_add(&msgbuf, line + len, org_len - len);
1335         strbuf_complete_line(&msgbuf);
1336         emit_diff_symbol(ecbdata->opt,
1337                          DIFF_SYMBOL_CONTEXT_FRAGINFO, msgbuf.buf, msgbuf.len, 0);
1338         strbuf_release(&msgbuf);
1339 }
1340
1341 static struct diff_tempfile *claim_diff_tempfile(void) {
1342         int i;
1343         for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
1344                 if (!diff_temp[i].name)
1345                         return diff_temp + i;
1346         die("BUG: diff is failing to clean up its tempfiles");
1347 }
1348
1349 static void remove_tempfile(void)
1350 {
1351         int i;
1352         for (i = 0; i < ARRAY_SIZE(diff_temp); i++) {
1353                 if (is_tempfile_active(diff_temp[i].tempfile))
1354                         delete_tempfile(&diff_temp[i].tempfile);
1355                 diff_temp[i].name = NULL;
1356         }
1357 }
1358
1359 static void add_line_count(struct strbuf *out, int count)
1360 {
1361         switch (count) {
1362         case 0:
1363                 strbuf_addstr(out, "0,0");
1364                 break;
1365         case 1:
1366                 strbuf_addstr(out, "1");
1367                 break;
1368         default:
1369                 strbuf_addf(out, "1,%d", count);
1370                 break;
1371         }
1372 }
1373
1374 static void emit_rewrite_lines(struct emit_callback *ecb,
1375                                int prefix, const char *data, int size)
1376 {
1377         const char *endp = NULL;
1378         const char *reset = diff_get_color(ecb->color_diff, DIFF_RESET);
1379
1380         while (0 < size) {
1381                 int len;
1382
1383                 endp = memchr(data, '\n', size);
1384                 len = endp ? (endp - data + 1) : size;
1385                 if (prefix != '+') {
1386                         ecb->lno_in_preimage++;
1387                         emit_del_line(reset, ecb, data, len);
1388                 } else {
1389                         ecb->lno_in_postimage++;
1390                         emit_add_line(reset, ecb, data, len);
1391                 }
1392                 size -= len;
1393                 data += len;
1394         }
1395         if (!endp)
1396                 emit_diff_symbol(ecb->opt, DIFF_SYMBOL_NO_LF_EOF, NULL, 0, 0);
1397 }
1398
1399 static void emit_rewrite_diff(const char *name_a,
1400                               const char *name_b,
1401                               struct diff_filespec *one,
1402                               struct diff_filespec *two,
1403                               struct userdiff_driver *textconv_one,
1404                               struct userdiff_driver *textconv_two,
1405                               struct diff_options *o)
1406 {
1407         int lc_a, lc_b;
1408         static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
1409         const char *a_prefix, *b_prefix;
1410         char *data_one, *data_two;
1411         size_t size_one, size_two;
1412         struct emit_callback ecbdata;
1413         struct strbuf out = STRBUF_INIT;
1414
1415         if (diff_mnemonic_prefix && o->flags.reverse_diff) {
1416                 a_prefix = o->b_prefix;
1417                 b_prefix = o->a_prefix;
1418         } else {
1419                 a_prefix = o->a_prefix;
1420                 b_prefix = o->b_prefix;
1421         }
1422
1423         name_a += (*name_a == '/');
1424         name_b += (*name_b == '/');
1425
1426         strbuf_reset(&a_name);
1427         strbuf_reset(&b_name);
1428         quote_two_c_style(&a_name, a_prefix, name_a, 0);
1429         quote_two_c_style(&b_name, b_prefix, name_b, 0);
1430
1431         size_one = fill_textconv(textconv_one, one, &data_one);
1432         size_two = fill_textconv(textconv_two, two, &data_two);
1433
1434         memset(&ecbdata, 0, sizeof(ecbdata));
1435         ecbdata.color_diff = want_color(o->use_color);
1436         ecbdata.ws_rule = whitespace_rule(name_b);
1437         ecbdata.opt = o;
1438         if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
1439                 mmfile_t mf1, mf2;
1440                 mf1.ptr = (char *)data_one;
1441                 mf2.ptr = (char *)data_two;
1442                 mf1.size = size_one;
1443                 mf2.size = size_two;
1444                 check_blank_at_eof(&mf1, &mf2, &ecbdata);
1445         }
1446         ecbdata.lno_in_preimage = 1;
1447         ecbdata.lno_in_postimage = 1;
1448
1449         lc_a = count_lines(data_one, size_one);
1450         lc_b = count_lines(data_two, size_two);
1451
1452         emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_MINUS,
1453                          a_name.buf, a_name.len, 0);
1454         emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_PLUS,
1455                          b_name.buf, b_name.len, 0);
1456
1457         strbuf_addstr(&out, "@@ -");
1458         if (!o->irreversible_delete)
1459                 add_line_count(&out, lc_a);
1460         else
1461                 strbuf_addstr(&out, "?,?");
1462         strbuf_addstr(&out, " +");
1463         add_line_count(&out, lc_b);
1464         strbuf_addstr(&out, " @@\n");
1465         emit_diff_symbol(o, DIFF_SYMBOL_REWRITE_DIFF, out.buf, out.len, 0);
1466         strbuf_release(&out);
1467
1468         if (lc_a && !o->irreversible_delete)
1469                 emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
1470         if (lc_b)
1471                 emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
1472         if (textconv_one)
1473                 free((char *)data_one);
1474         if (textconv_two)
1475                 free((char *)data_two);
1476 }
1477
1478 struct diff_words_buffer {
1479         mmfile_t text;
1480         unsigned long alloc;
1481         struct diff_words_orig {
1482                 const char *begin, *end;
1483         } *orig;
1484         int orig_nr, orig_alloc;
1485 };
1486
1487 static void diff_words_append(char *line, unsigned long len,
1488                 struct diff_words_buffer *buffer)
1489 {
1490         ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
1491         line++;
1492         len--;
1493         memcpy(buffer->text.ptr + buffer->text.size, line, len);
1494         buffer->text.size += len;
1495         buffer->text.ptr[buffer->text.size] = '\0';
1496 }
1497
1498 struct diff_words_style_elem {
1499         const char *prefix;
1500         const char *suffix;
1501         const char *color; /* NULL; filled in by the setup code if
1502                             * color is enabled */
1503 };
1504
1505 struct diff_words_style {
1506         enum diff_words_type type;
1507         struct diff_words_style_elem new, old, ctx;
1508         const char *newline;
1509 };
1510
1511 static struct diff_words_style diff_words_styles[] = {
1512         { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
1513         { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
1514         { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
1515 };
1516
1517 struct diff_words_data {
1518         struct diff_words_buffer minus, plus;
1519         const char *current_plus;
1520         int last_minus;
1521         struct diff_options *opt;
1522         regex_t *word_regex;
1523         enum diff_words_type type;
1524         struct diff_words_style *style;
1525 };
1526
1527 static int fn_out_diff_words_write_helper(struct diff_options *o,
1528                                           struct diff_words_style_elem *st_el,
1529                                           const char *newline,
1530                                           size_t count, const char *buf)
1531 {
1532         int print = 0;
1533         struct strbuf sb = STRBUF_INIT;
1534
1535         while (count) {
1536                 char *p = memchr(buf, '\n', count);
1537                 if (print)
1538                         strbuf_addstr(&sb, diff_line_prefix(o));
1539
1540                 if (p != buf) {
1541                         const char *reset = st_el->color && *st_el->color ?
1542                                             GIT_COLOR_RESET : NULL;
1543                         if (st_el->color && *st_el->color)
1544                                 strbuf_addstr(&sb, st_el->color);
1545                         strbuf_addstr(&sb, st_el->prefix);
1546                         strbuf_add(&sb, buf, p ? p - buf : count);
1547                         strbuf_addstr(&sb, st_el->suffix);
1548                         if (reset)
1549                                 strbuf_addstr(&sb, reset);
1550                 }
1551                 if (!p)
1552                         goto out;
1553
1554                 strbuf_addstr(&sb, newline);
1555                 count -= p + 1 - buf;
1556                 buf = p + 1;
1557                 print = 1;
1558                 if (count) {
1559                         emit_diff_symbol(o, DIFF_SYMBOL_WORD_DIFF,
1560                                          sb.buf, sb.len, 0);
1561                         strbuf_reset(&sb);
1562                 }
1563         }
1564
1565 out:
1566         if (sb.len)
1567                 emit_diff_symbol(o, DIFF_SYMBOL_WORD_DIFF,
1568                                  sb.buf, sb.len, 0);
1569         strbuf_release(&sb);
1570         return 0;
1571 }
1572
1573 /*
1574  * '--color-words' algorithm can be described as:
1575  *
1576  *   1. collect the minus/plus lines of a diff hunk, divided into
1577  *      minus-lines and plus-lines;
1578  *
1579  *   2. break both minus-lines and plus-lines into words and
1580  *      place them into two mmfile_t with one word for each line;
1581  *
1582  *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
1583  *
1584  * And for the common parts of the both file, we output the plus side text.
1585  * diff_words->current_plus is used to trace the current position of the plus file
1586  * which printed. diff_words->last_minus is used to trace the last minus word
1587  * printed.
1588  *
1589  * For '--graph' to work with '--color-words', we need to output the graph prefix
1590  * on each line of color words output. Generally, there are two conditions on
1591  * which we should output the prefix.
1592  *
1593  *   1. diff_words->last_minus == 0 &&
1594  *      diff_words->current_plus == diff_words->plus.text.ptr
1595  *
1596  *      that is: the plus text must start as a new line, and if there is no minus
1597  *      word printed, a graph prefix must be printed.
1598  *
1599  *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
1600  *      *(diff_words->current_plus - 1) == '\n'
1601  *
1602  *      that is: a graph prefix must be printed following a '\n'
1603  */
1604 static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
1605 {
1606         if ((diff_words->last_minus == 0 &&
1607                 diff_words->current_plus == diff_words->plus.text.ptr) ||
1608                 (diff_words->current_plus > diff_words->plus.text.ptr &&
1609                 *(diff_words->current_plus - 1) == '\n')) {
1610                 return 1;
1611         } else {
1612                 return 0;
1613         }
1614 }
1615
1616 static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
1617 {
1618         struct diff_words_data *diff_words = priv;
1619         struct diff_words_style *style = diff_words->style;
1620         int minus_first, minus_len, plus_first, plus_len;
1621         const char *minus_begin, *minus_end, *plus_begin, *plus_end;
1622         struct diff_options *opt = diff_words->opt;
1623         const char *line_prefix;
1624
1625         if (line[0] != '@' || parse_hunk_header(line, len,
1626                         &minus_first, &minus_len, &plus_first, &plus_len))
1627                 return;
1628
1629         assert(opt);
1630         line_prefix = diff_line_prefix(opt);
1631
1632         /* POSIX requires that first be decremented by one if len == 0... */
1633         if (minus_len) {
1634                 minus_begin = diff_words->minus.orig[minus_first].begin;
1635                 minus_end =
1636                         diff_words->minus.orig[minus_first + minus_len - 1].end;
1637         } else
1638                 minus_begin = minus_end =
1639                         diff_words->minus.orig[minus_first].end;
1640
1641         if (plus_len) {
1642                 plus_begin = diff_words->plus.orig[plus_first].begin;
1643                 plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
1644         } else
1645                 plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
1646
1647         if (color_words_output_graph_prefix(diff_words)) {
1648                 fputs(line_prefix, diff_words->opt->file);
1649         }
1650         if (diff_words->current_plus != plus_begin) {
1651                 fn_out_diff_words_write_helper(diff_words->opt,
1652                                 &style->ctx, style->newline,
1653                                 plus_begin - diff_words->current_plus,
1654                                 diff_words->current_plus);
1655         }
1656         if (minus_begin != minus_end) {
1657                 fn_out_diff_words_write_helper(diff_words->opt,
1658                                 &style->old, style->newline,
1659                                 minus_end - minus_begin, minus_begin);
1660         }
1661         if (plus_begin != plus_end) {
1662                 fn_out_diff_words_write_helper(diff_words->opt,
1663                                 &style->new, style->newline,
1664                                 plus_end - plus_begin, plus_begin);
1665         }
1666
1667         diff_words->current_plus = plus_end;
1668         diff_words->last_minus = minus_first;
1669 }
1670
1671 /* This function starts looking at *begin, and returns 0 iff a word was found. */
1672 static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
1673                 int *begin, int *end)
1674 {
1675         if (word_regex && *begin < buffer->size) {
1676                 regmatch_t match[1];
1677                 if (!regexec_buf(word_regex, buffer->ptr + *begin,
1678                                  buffer->size - *begin, 1, match, 0)) {
1679                         char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
1680                                         '\n', match[0].rm_eo - match[0].rm_so);
1681                         *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
1682                         *begin += match[0].rm_so;
1683                         return *begin >= *end;
1684                 }
1685                 return -1;
1686         }
1687
1688         /* find the next word */
1689         while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
1690                 (*begin)++;
1691         if (*begin >= buffer->size)
1692                 return -1;
1693
1694         /* find the end of the word */
1695         *end = *begin + 1;
1696         while (*end < buffer->size && !isspace(buffer->ptr[*end]))
1697                 (*end)++;
1698
1699         return 0;
1700 }
1701
1702 /*
1703  * This function splits the words in buffer->text, stores the list with
1704  * newline separator into out, and saves the offsets of the original words
1705  * in buffer->orig.
1706  */
1707 static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
1708                 regex_t *word_regex)
1709 {
1710         int i, j;
1711         long alloc = 0;
1712
1713         out->size = 0;
1714         out->ptr = NULL;
1715
1716         /* fake an empty "0th" word */
1717         ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
1718         buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
1719         buffer->orig_nr = 1;
1720
1721         for (i = 0; i < buffer->text.size; i++) {
1722                 if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
1723                         return;
1724
1725                 /* store original boundaries */
1726                 ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
1727                                 buffer->orig_alloc);
1728                 buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
1729                 buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
1730                 buffer->orig_nr++;
1731
1732                 /* store one word */
1733                 ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
1734                 memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
1735                 out->ptr[out->size + j - i] = '\n';
1736                 out->size += j - i + 1;
1737
1738                 i = j - 1;
1739         }
1740 }
1741
1742 /* this executes the word diff on the accumulated buffers */
1743 static void diff_words_show(struct diff_words_data *diff_words)
1744 {
1745         xpparam_t xpp;
1746         xdemitconf_t xecfg;
1747         mmfile_t minus, plus;
1748         struct diff_words_style *style = diff_words->style;
1749
1750         struct diff_options *opt = diff_words->opt;
1751         const char *line_prefix;
1752
1753         assert(opt);
1754         line_prefix = diff_line_prefix(opt);
1755
1756         /* special case: only removal */
1757         if (!diff_words->plus.text.size) {
1758                 emit_diff_symbol(diff_words->opt, DIFF_SYMBOL_WORD_DIFF,
1759                                  line_prefix, strlen(line_prefix), 0);
1760                 fn_out_diff_words_write_helper(diff_words->opt,
1761                         &style->old, style->newline,
1762                         diff_words->minus.text.size,
1763                         diff_words->minus.text.ptr);
1764                 diff_words->minus.text.size = 0;
1765                 return;
1766         }
1767
1768         diff_words->current_plus = diff_words->plus.text.ptr;
1769         diff_words->last_minus = 0;
1770
1771         memset(&xpp, 0, sizeof(xpp));
1772         memset(&xecfg, 0, sizeof(xecfg));
1773         diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
1774         diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
1775         xpp.flags = 0;
1776         /* as only the hunk header will be parsed, we need a 0-context */
1777         xecfg.ctxlen = 0;
1778         if (xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
1779                           &xpp, &xecfg))
1780                 die("unable to generate word diff");
1781         free(minus.ptr);
1782         free(plus.ptr);
1783         if (diff_words->current_plus != diff_words->plus.text.ptr +
1784                         diff_words->plus.text.size) {
1785                 if (color_words_output_graph_prefix(diff_words))
1786                         emit_diff_symbol(diff_words->opt, DIFF_SYMBOL_WORD_DIFF,
1787                                          line_prefix, strlen(line_prefix), 0);
1788                 fn_out_diff_words_write_helper(diff_words->opt,
1789                         &style->ctx, style->newline,
1790                         diff_words->plus.text.ptr + diff_words->plus.text.size
1791                         - diff_words->current_plus, diff_words->current_plus);
1792         }
1793         diff_words->minus.text.size = diff_words->plus.text.size = 0;
1794 }
1795
1796 /* In "color-words" mode, show word-diff of words accumulated in the buffer */
1797 static void diff_words_flush(struct emit_callback *ecbdata)
1798 {
1799         struct diff_options *wo = ecbdata->diff_words->opt;
1800
1801         if (ecbdata->diff_words->minus.text.size ||
1802             ecbdata->diff_words->plus.text.size)
1803                 diff_words_show(ecbdata->diff_words);
1804
1805         if (wo->emitted_symbols) {
1806                 struct diff_options *o = ecbdata->opt;
1807                 struct emitted_diff_symbols *wol = wo->emitted_symbols;
1808                 int i;
1809
1810                 /*
1811                  * NEEDSWORK:
1812                  * Instead of appending each, concat all words to a line?
1813                  */
1814                 for (i = 0; i < wol->nr; i++)
1815                         append_emitted_diff_symbol(o, &wol->buf[i]);
1816
1817                 for (i = 0; i < wol->nr; i++)
1818                         free((void *)wol->buf[i].line);
1819
1820                 wol->nr = 0;
1821         }
1822 }
1823
1824 static void diff_filespec_load_driver(struct diff_filespec *one)
1825 {
1826         /* Use already-loaded driver */
1827         if (one->driver)
1828                 return;
1829
1830         if (S_ISREG(one->mode))
1831                 one->driver = userdiff_find_by_path(one->path);
1832
1833         /* Fallback to default settings */
1834         if (!one->driver)
1835                 one->driver = userdiff_find_by_name("default");
1836 }
1837
1838 static const char *userdiff_word_regex(struct diff_filespec *one)
1839 {
1840         diff_filespec_load_driver(one);
1841         return one->driver->word_regex;
1842 }
1843
1844 static void init_diff_words_data(struct emit_callback *ecbdata,
1845                                  struct diff_options *orig_opts,
1846                                  struct diff_filespec *one,
1847                                  struct diff_filespec *two)
1848 {
1849         int i;
1850         struct diff_options *o = xmalloc(sizeof(struct diff_options));
1851         memcpy(o, orig_opts, sizeof(struct diff_options));
1852
1853         ecbdata->diff_words =
1854                 xcalloc(1, sizeof(struct diff_words_data));
1855         ecbdata->diff_words->type = o->word_diff;
1856         ecbdata->diff_words->opt = o;
1857
1858         if (orig_opts->emitted_symbols)
1859                 o->emitted_symbols =
1860                         xcalloc(1, sizeof(struct emitted_diff_symbols));
1861
1862         if (!o->word_regex)
1863                 o->word_regex = userdiff_word_regex(one);
1864         if (!o->word_regex)
1865                 o->word_regex = userdiff_word_regex(two);
1866         if (!o->word_regex)
1867                 o->word_regex = diff_word_regex_cfg;
1868         if (o->word_regex) {
1869                 ecbdata->diff_words->word_regex = (regex_t *)
1870                         xmalloc(sizeof(regex_t));
1871                 if (regcomp(ecbdata->diff_words->word_regex,
1872                             o->word_regex,
1873                             REG_EXTENDED | REG_NEWLINE))
1874                         die ("Invalid regular expression: %s",
1875                              o->word_regex);
1876         }
1877         for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
1878                 if (o->word_diff == diff_words_styles[i].type) {
1879                         ecbdata->diff_words->style =
1880                                 &diff_words_styles[i];
1881                         break;
1882                 }
1883         }
1884         if (want_color(o->use_color)) {
1885                 struct diff_words_style *st = ecbdata->diff_words->style;
1886                 st->old.color = diff_get_color_opt(o, DIFF_FILE_OLD);
1887                 st->new.color = diff_get_color_opt(o, DIFF_FILE_NEW);
1888                 st->ctx.color = diff_get_color_opt(o, DIFF_CONTEXT);
1889         }
1890 }
1891
1892 static void free_diff_words_data(struct emit_callback *ecbdata)
1893 {
1894         if (ecbdata->diff_words) {
1895                 diff_words_flush(ecbdata);
1896                 free (ecbdata->diff_words->opt->emitted_symbols);
1897                 free (ecbdata->diff_words->opt);
1898                 free (ecbdata->diff_words->minus.text.ptr);
1899                 free (ecbdata->diff_words->minus.orig);
1900                 free (ecbdata->diff_words->plus.text.ptr);
1901                 free (ecbdata->diff_words->plus.orig);
1902                 if (ecbdata->diff_words->word_regex) {
1903                         regfree(ecbdata->diff_words->word_regex);
1904                         free(ecbdata->diff_words->word_regex);
1905                 }
1906                 FREE_AND_NULL(ecbdata->diff_words);
1907         }
1908 }
1909
1910 const char *diff_get_color(int diff_use_color, enum color_diff ix)
1911 {
1912         if (want_color(diff_use_color))
1913                 return diff_colors[ix];
1914         return "";
1915 }
1916
1917 const char *diff_line_prefix(struct diff_options *opt)
1918 {
1919         struct strbuf *msgbuf;
1920         if (!opt->output_prefix)
1921                 return "";
1922
1923         msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
1924         return msgbuf->buf;
1925 }
1926
1927 static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
1928 {
1929         const char *cp;
1930         unsigned long allot;
1931         size_t l = len;
1932
1933         cp = line;
1934         allot = l;
1935         while (0 < l) {
1936                 (void) utf8_width(&cp, &l);
1937                 if (!cp)
1938                         break; /* truncated in the middle? */
1939         }
1940         return allot - l;
1941 }
1942
1943 static void find_lno(const char *line, struct emit_callback *ecbdata)
1944 {
1945         const char *p;
1946         ecbdata->lno_in_preimage = 0;
1947         ecbdata->lno_in_postimage = 0;
1948         p = strchr(line, '-');
1949         if (!p)
1950                 return; /* cannot happen */
1951         ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
1952         p = strchr(p, '+');
1953         if (!p)
1954                 return; /* cannot happen */
1955         ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
1956 }
1957
1958 static void fn_out_consume(void *priv, char *line, unsigned long len)
1959 {
1960         struct emit_callback *ecbdata = priv;
1961         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1962         struct diff_options *o = ecbdata->opt;
1963
1964         o->found_changes = 1;
1965
1966         if (ecbdata->header) {
1967                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
1968                                  ecbdata->header->buf, ecbdata->header->len, 0);
1969                 strbuf_reset(ecbdata->header);
1970                 ecbdata->header = NULL;
1971         }
1972
1973         if (ecbdata->label_path[0]) {
1974                 emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_MINUS,
1975                                  ecbdata->label_path[0],
1976                                  strlen(ecbdata->label_path[0]), 0);
1977                 emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_PLUS,
1978                                  ecbdata->label_path[1],
1979                                  strlen(ecbdata->label_path[1]), 0);
1980                 ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
1981         }
1982
1983         if (diff_suppress_blank_empty
1984             && len == 2 && line[0] == ' ' && line[1] == '\n') {
1985                 line[0] = '\n';
1986                 len = 1;
1987         }
1988
1989         if (line[0] == '@') {
1990                 if (ecbdata->diff_words)
1991                         diff_words_flush(ecbdata);
1992                 len = sane_truncate_line(ecbdata, line, len);
1993                 find_lno(line, ecbdata);
1994                 emit_hunk_header(ecbdata, line, len);
1995                 return;
1996         }
1997
1998         if (ecbdata->diff_words) {
1999                 enum diff_symbol s =
2000                         ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN ?
2001                         DIFF_SYMBOL_WORDS_PORCELAIN : DIFF_SYMBOL_WORDS;
2002                 if (line[0] == '-') {
2003                         diff_words_append(line, len,
2004                                           &ecbdata->diff_words->minus);
2005                         return;
2006                 } else if (line[0] == '+') {
2007                         diff_words_append(line, len,
2008                                           &ecbdata->diff_words->plus);
2009                         return;
2010                 } else if (starts_with(line, "\\ ")) {
2011                         /*
2012                          * Eat the "no newline at eof" marker as if we
2013                          * saw a "+" or "-" line with nothing on it,
2014                          * and return without diff_words_flush() to
2015                          * defer processing. If this is the end of
2016                          * preimage, more "+" lines may come after it.
2017                          */
2018                         return;
2019                 }
2020                 diff_words_flush(ecbdata);
2021                 emit_diff_symbol(o, s, line, len, 0);
2022                 return;
2023         }
2024
2025         switch (line[0]) {
2026         case '+':
2027                 ecbdata->lno_in_postimage++;
2028                 emit_add_line(reset, ecbdata, line + 1, len - 1);
2029                 break;
2030         case '-':
2031                 ecbdata->lno_in_preimage++;
2032                 emit_del_line(reset, ecbdata, line + 1, len - 1);
2033                 break;
2034         case ' ':
2035                 ecbdata->lno_in_postimage++;
2036                 ecbdata->lno_in_preimage++;
2037                 emit_context_line(reset, ecbdata, line + 1, len - 1);
2038                 break;
2039         default:
2040                 /* incomplete line at the end */
2041                 ecbdata->lno_in_preimage++;
2042                 emit_diff_symbol(o, DIFF_SYMBOL_CONTEXT_INCOMPLETE,
2043                                  line, len, 0);
2044                 break;
2045         }
2046 }
2047
2048 static char *pprint_rename(const char *a, const char *b)
2049 {
2050         const char *old = a;
2051         const char *new = b;
2052         struct strbuf name = STRBUF_INIT;
2053         int pfx_length, sfx_length;
2054         int pfx_adjust_for_slash;
2055         int len_a = strlen(a);
2056         int len_b = strlen(b);
2057         int a_midlen, b_midlen;
2058         int qlen_a = quote_c_style(a, NULL, NULL, 0);
2059         int qlen_b = quote_c_style(b, NULL, NULL, 0);
2060
2061         if (qlen_a || qlen_b) {
2062                 quote_c_style(a, &name, NULL, 0);
2063                 strbuf_addstr(&name, " => ");
2064                 quote_c_style(b, &name, NULL, 0);
2065                 return strbuf_detach(&name, NULL);
2066         }
2067
2068         /* Find common prefix */
2069         pfx_length = 0;
2070         while (*old && *new && *old == *new) {
2071                 if (*old == '/')
2072                         pfx_length = old - a + 1;
2073                 old++;
2074                 new++;
2075         }
2076
2077         /* Find common suffix */
2078         old = a + len_a;
2079         new = b + len_b;
2080         sfx_length = 0;
2081         /*
2082          * If there is a common prefix, it must end in a slash.  In
2083          * that case we let this loop run 1 into the prefix to see the
2084          * same slash.
2085          *
2086          * If there is no common prefix, we cannot do this as it would
2087          * underrun the input strings.
2088          */
2089         pfx_adjust_for_slash = (pfx_length ? 1 : 0);
2090         while (a + pfx_length - pfx_adjust_for_slash <= old &&
2091                b + pfx_length - pfx_adjust_for_slash <= new &&
2092                *old == *new) {
2093                 if (*old == '/')
2094                         sfx_length = len_a - (old - a);
2095                 old--;
2096                 new--;
2097         }
2098
2099         /*
2100          * pfx{mid-a => mid-b}sfx
2101          * {pfx-a => pfx-b}sfx
2102          * pfx{sfx-a => sfx-b}
2103          * name-a => name-b
2104          */
2105         a_midlen = len_a - pfx_length - sfx_length;
2106         b_midlen = len_b - pfx_length - sfx_length;
2107         if (a_midlen < 0)
2108                 a_midlen = 0;
2109         if (b_midlen < 0)
2110                 b_midlen = 0;
2111
2112         strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
2113         if (pfx_length + sfx_length) {
2114                 strbuf_add(&name, a, pfx_length);
2115                 strbuf_addch(&name, '{');
2116         }
2117         strbuf_add(&name, a + pfx_length, a_midlen);
2118         strbuf_addstr(&name, " => ");
2119         strbuf_add(&name, b + pfx_length, b_midlen);
2120         if (pfx_length + sfx_length) {
2121                 strbuf_addch(&name, '}');
2122                 strbuf_add(&name, a + len_a - sfx_length, sfx_length);
2123         }
2124         return strbuf_detach(&name, NULL);
2125 }
2126
2127 struct diffstat_t {
2128         int nr;
2129         int alloc;
2130         struct diffstat_file {
2131                 char *from_name;
2132                 char *name;
2133                 char *print_name;
2134                 unsigned is_unmerged:1;
2135                 unsigned is_binary:1;
2136                 unsigned is_renamed:1;
2137                 unsigned is_interesting:1;
2138                 uintmax_t added, deleted;
2139         } **files;
2140 };
2141
2142 static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
2143                                           const char *name_a,
2144                                           const char *name_b)
2145 {
2146         struct diffstat_file *x;
2147         x = xcalloc(1, sizeof(*x));
2148         ALLOC_GROW(diffstat->files, diffstat->nr + 1, diffstat->alloc);
2149         diffstat->files[diffstat->nr++] = x;
2150         if (name_b) {
2151                 x->from_name = xstrdup(name_a);
2152                 x->name = xstrdup(name_b);
2153                 x->is_renamed = 1;
2154         }
2155         else {
2156                 x->from_name = NULL;
2157                 x->name = xstrdup(name_a);
2158         }
2159         return x;
2160 }
2161
2162 static void diffstat_consume(void *priv, char *line, unsigned long len)
2163 {
2164         struct diffstat_t *diffstat = priv;
2165         struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
2166
2167         if (line[0] == '+')
2168                 x->added++;
2169         else if (line[0] == '-')
2170                 x->deleted++;
2171 }
2172
2173 const char mime_boundary_leader[] = "------------";
2174
2175 static int scale_linear(int it, int width, int max_change)
2176 {
2177         if (!it)
2178                 return 0;
2179         /*
2180          * make sure that at least one '-' or '+' is printed if
2181          * there is any change to this path. The easiest way is to
2182          * scale linearly as if the alloted width is one column shorter
2183          * than it is, and then add 1 to the result.
2184          */
2185         return 1 + (it * (width - 1) / max_change);
2186 }
2187
2188 static void show_graph(struct strbuf *out, char ch, int cnt,
2189                        const char *set, const char *reset)
2190 {
2191         if (cnt <= 0)
2192                 return;
2193         strbuf_addstr(out, set);
2194         strbuf_addchars(out, ch, cnt);
2195         strbuf_addstr(out, reset);
2196 }
2197
2198 static void fill_print_name(struct diffstat_file *file)
2199 {
2200         char *pname;
2201
2202         if (file->print_name)
2203                 return;
2204
2205         if (!file->is_renamed) {
2206                 struct strbuf buf = STRBUF_INIT;
2207                 if (quote_c_style(file->name, &buf, NULL, 0)) {
2208                         pname = strbuf_detach(&buf, NULL);
2209                 } else {
2210                         pname = file->name;
2211                         strbuf_release(&buf);
2212                 }
2213         } else {
2214                 pname = pprint_rename(file->from_name, file->name);
2215         }
2216         file->print_name = pname;
2217 }
2218
2219 static void print_stat_summary_inserts_deletes(struct diff_options *options,
2220                 int files, int insertions, int deletions)
2221 {
2222         struct strbuf sb = STRBUF_INIT;
2223
2224         if (!files) {
2225                 assert(insertions == 0 && deletions == 0);
2226                 emit_diff_symbol(options, DIFF_SYMBOL_STATS_SUMMARY_NO_FILES,
2227                                  NULL, 0, 0);
2228                 return;
2229         }
2230
2231         strbuf_addf(&sb,
2232                     (files == 1) ? " %d file changed" : " %d files changed",
2233                     files);
2234
2235         /*
2236          * For binary diff, the caller may want to print "x files
2237          * changed" with insertions == 0 && deletions == 0.
2238          *
2239          * Not omitting "0 insertions(+), 0 deletions(-)" in this case
2240          * is probably less confusing (i.e skip over "2 files changed
2241          * but nothing about added/removed lines? Is this a bug in Git?").
2242          */
2243         if (insertions || deletions == 0) {
2244                 strbuf_addf(&sb,
2245                             (insertions == 1) ? ", %d insertion(+)" : ", %d insertions(+)",
2246                             insertions);
2247         }
2248
2249         if (deletions || insertions == 0) {
2250                 strbuf_addf(&sb,
2251                             (deletions == 1) ? ", %d deletion(-)" : ", %d deletions(-)",
2252                             deletions);
2253         }
2254         strbuf_addch(&sb, '\n');
2255         emit_diff_symbol(options, DIFF_SYMBOL_STATS_SUMMARY_INSERTS_DELETES,
2256                          sb.buf, sb.len, 0);
2257         strbuf_release(&sb);
2258 }
2259
2260 void print_stat_summary(FILE *fp, int files,
2261                         int insertions, int deletions)
2262 {
2263         struct diff_options o;
2264         memset(&o, 0, sizeof(o));
2265         o.file = fp;
2266
2267         print_stat_summary_inserts_deletes(&o, files, insertions, deletions);
2268 }
2269
2270 static void show_stats(struct diffstat_t *data, struct diff_options *options)
2271 {
2272         int i, len, add, del, adds = 0, dels = 0;
2273         uintmax_t max_change = 0, max_len = 0;
2274         int total_files = data->nr, count;
2275         int width, name_width, graph_width, number_width = 0, bin_width = 0;
2276         const char *reset, *add_c, *del_c;
2277         int extra_shown = 0;
2278         const char *line_prefix = diff_line_prefix(options);
2279         struct strbuf out = STRBUF_INIT;
2280
2281         if (data->nr == 0)
2282                 return;
2283
2284         count = options->stat_count ? options->stat_count : data->nr;
2285
2286         reset = diff_get_color_opt(options, DIFF_RESET);
2287         add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
2288         del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
2289
2290         /*
2291          * Find the longest filename and max number of changes
2292          */
2293         for (i = 0; (i < count) && (i < data->nr); i++) {
2294                 struct diffstat_file *file = data->files[i];
2295                 uintmax_t change = file->added + file->deleted;
2296
2297                 if (!file->is_interesting && (change == 0)) {
2298                         count++; /* not shown == room for one more */
2299                         continue;
2300                 }
2301                 fill_print_name(file);
2302                 len = strlen(file->print_name);
2303                 if (max_len < len)
2304                         max_len = len;
2305
2306                 if (file->is_unmerged) {
2307                         /* "Unmerged" is 8 characters */
2308                         bin_width = bin_width < 8 ? 8 : bin_width;
2309                         continue;
2310                 }
2311                 if (file->is_binary) {
2312                         /* "Bin XXX -> YYY bytes" */
2313                         int w = 14 + decimal_width(file->added)
2314                                 + decimal_width(file->deleted);
2315                         bin_width = bin_width < w ? w : bin_width;
2316                         /* Display change counts aligned with "Bin" */
2317                         number_width = 3;
2318                         continue;
2319                 }
2320
2321                 if (max_change < change)
2322                         max_change = change;
2323         }
2324         count = i; /* where we can stop scanning in data->files[] */
2325
2326         /*
2327          * We have width = stat_width or term_columns() columns total.
2328          * We want a maximum of min(max_len, stat_name_width) for the name part.
2329          * We want a maximum of min(max_change, stat_graph_width) for the +- part.
2330          * We also need 1 for " " and 4 + decimal_width(max_change)
2331          * for " | NNNN " and one the empty column at the end, altogether
2332          * 6 + decimal_width(max_change).
2333          *
2334          * If there's not enough space, we will use the smaller of
2335          * stat_name_width (if set) and 5/8*width for the filename,
2336          * and the rest for constant elements + graph part, but no more
2337          * than stat_graph_width for the graph part.
2338          * (5/8 gives 50 for filename and 30 for the constant parts + graph
2339          * for the standard terminal size).
2340          *
2341          * In other words: stat_width limits the maximum width, and
2342          * stat_name_width fixes the maximum width of the filename,
2343          * and is also used to divide available columns if there
2344          * aren't enough.
2345          *
2346          * Binary files are displayed with "Bin XXX -> YYY bytes"
2347          * instead of the change count and graph. This part is treated
2348          * similarly to the graph part, except that it is not
2349          * "scaled". If total width is too small to accommodate the
2350          * guaranteed minimum width of the filename part and the
2351          * separators and this message, this message will "overflow"
2352          * making the line longer than the maximum width.
2353          */
2354
2355         if (options->stat_width == -1)
2356                 width = term_columns() - strlen(line_prefix);
2357         else
2358                 width = options->stat_width ? options->stat_width : 80;
2359         number_width = decimal_width(max_change) > number_width ?
2360                 decimal_width(max_change) : number_width;
2361
2362         if (options->stat_graph_width == -1)
2363                 options->stat_graph_width = diff_stat_graph_width;
2364
2365         /*
2366          * Guarantee 3/8*16==6 for the graph part
2367          * and 5/8*16==10 for the filename part
2368          */
2369         if (width < 16 + 6 + number_width)
2370                 width = 16 + 6 + number_width;
2371
2372         /*
2373          * First assign sizes that are wanted, ignoring available width.
2374          * strlen("Bin XXX -> YYY bytes") == bin_width, and the part
2375          * starting from "XXX" should fit in graph_width.
2376          */
2377         graph_width = max_change + 4 > bin_width ? max_change : bin_width - 4;
2378         if (options->stat_graph_width &&
2379             options->stat_graph_width < graph_width)
2380                 graph_width = options->stat_graph_width;
2381
2382         name_width = (options->stat_name_width > 0 &&
2383                       options->stat_name_width < max_len) ?
2384                 options->stat_name_width : max_len;
2385
2386         /*
2387          * Adjust adjustable widths not to exceed maximum width
2388          */
2389         if (name_width + number_width + 6 + graph_width > width) {
2390                 if (graph_width > width * 3/8 - number_width - 6) {
2391                         graph_width = width * 3/8 - number_width - 6;
2392                         if (graph_width < 6)
2393                                 graph_width = 6;
2394                 }
2395
2396                 if (options->stat_graph_width &&
2397                     graph_width > options->stat_graph_width)
2398                         graph_width = options->stat_graph_width;
2399                 if (name_width > width - number_width - 6 - graph_width)
2400                         name_width = width - number_width - 6 - graph_width;
2401                 else
2402                         graph_width = width - number_width - 6 - name_width;
2403         }
2404
2405         /*
2406          * From here name_width is the width of the name area,
2407          * and graph_width is the width of the graph area.
2408          * max_change is used to scale graph properly.
2409          */
2410         for (i = 0; i < count; i++) {
2411                 const char *prefix = "";
2412                 struct diffstat_file *file = data->files[i];
2413                 char *name = file->print_name;
2414                 uintmax_t added = file->added;
2415                 uintmax_t deleted = file->deleted;
2416                 int name_len;
2417
2418                 if (!file->is_interesting && (added + deleted == 0))
2419                         continue;
2420
2421                 /*
2422                  * "scale" the filename
2423                  */
2424                 len = name_width;
2425                 name_len = strlen(name);
2426                 if (name_width < name_len) {
2427                         char *slash;
2428                         prefix = "...";
2429                         len -= 3;
2430                         name += name_len - len;
2431                         slash = strchr(name, '/');
2432                         if (slash)
2433                                 name = slash;
2434                 }
2435
2436                 if (file->is_binary) {
2437                         strbuf_addf(&out, " %s%-*s |", prefix, len, name);
2438                         strbuf_addf(&out, " %*s", number_width, "Bin");
2439                         if (!added && !deleted) {
2440                                 strbuf_addch(&out, '\n');
2441                                 emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2442                                                  out.buf, out.len, 0);
2443                                 strbuf_reset(&out);
2444                                 continue;
2445                         }
2446                         strbuf_addf(&out, " %s%"PRIuMAX"%s",
2447                                 del_c, deleted, reset);
2448                         strbuf_addstr(&out, " -> ");
2449                         strbuf_addf(&out, "%s%"PRIuMAX"%s",
2450                                 add_c, added, reset);
2451                         strbuf_addstr(&out, " bytes\n");
2452                         emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2453                                          out.buf, out.len, 0);
2454                         strbuf_reset(&out);
2455                         continue;
2456                 }
2457                 else if (file->is_unmerged) {
2458                         strbuf_addf(&out, " %s%-*s |", prefix, len, name);
2459                         strbuf_addstr(&out, " Unmerged\n");
2460                         emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2461                                          out.buf, out.len, 0);
2462                         strbuf_reset(&out);
2463                         continue;
2464                 }
2465
2466                 /*
2467                  * scale the add/delete
2468                  */
2469                 add = added;
2470                 del = deleted;
2471
2472                 if (graph_width <= max_change) {
2473                         int total = scale_linear(add + del, graph_width, max_change);
2474                         if (total < 2 && add && del)
2475                                 /* width >= 2 due to the sanity check */
2476                                 total = 2;
2477                         if (add < del) {
2478                                 add = scale_linear(add, graph_width, max_change);
2479                                 del = total - add;
2480                         } else {
2481                                 del = scale_linear(del, graph_width, max_change);
2482                                 add = total - del;
2483                         }
2484                 }
2485                 strbuf_addf(&out, " %s%-*s |", prefix, len, name);
2486                 strbuf_addf(&out, " %*"PRIuMAX"%s",
2487                         number_width, added + deleted,
2488                         added + deleted ? " " : "");
2489                 show_graph(&out, '+', add, add_c, reset);
2490                 show_graph(&out, '-', del, del_c, reset);
2491                 strbuf_addch(&out, '\n');
2492                 emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2493                                  out.buf, out.len, 0);
2494                 strbuf_reset(&out);
2495         }
2496
2497         for (i = 0; i < data->nr; i++) {
2498                 struct diffstat_file *file = data->files[i];
2499                 uintmax_t added = file->added;
2500                 uintmax_t deleted = file->deleted;
2501
2502                 if (file->is_unmerged ||
2503                     (!file->is_interesting && (added + deleted == 0))) {
2504                         total_files--;
2505                         continue;
2506                 }
2507
2508                 if (!file->is_binary) {
2509                         adds += added;
2510                         dels += deleted;
2511                 }
2512                 if (i < count)
2513                         continue;
2514                 if (!extra_shown)
2515                         emit_diff_symbol(options,
2516                                          DIFF_SYMBOL_STATS_SUMMARY_ABBREV,
2517                                          NULL, 0, 0);
2518                 extra_shown = 1;
2519         }
2520
2521         print_stat_summary_inserts_deletes(options, total_files, adds, dels);
2522         strbuf_release(&out);
2523 }
2524
2525 static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
2526 {
2527         int i, adds = 0, dels = 0, total_files = data->nr;
2528
2529         if (data->nr == 0)
2530                 return;
2531
2532         for (i = 0; i < data->nr; i++) {
2533                 int added = data->files[i]->added;
2534                 int deleted = data->files[i]->deleted;
2535
2536                 if (data->files[i]->is_unmerged ||
2537                     (!data->files[i]->is_interesting && (added + deleted == 0))) {
2538                         total_files--;
2539                 } else if (!data->files[i]->is_binary) { /* don't count bytes */
2540                         adds += added;
2541                         dels += deleted;
2542                 }
2543         }
2544         print_stat_summary_inserts_deletes(options, total_files, adds, dels);
2545 }
2546
2547 static void show_numstat(struct diffstat_t *data, struct diff_options *options)
2548 {
2549         int i;
2550
2551         if (data->nr == 0)
2552                 return;
2553
2554         for (i = 0; i < data->nr; i++) {
2555                 struct diffstat_file *file = data->files[i];
2556
2557                 fprintf(options->file, "%s", diff_line_prefix(options));
2558
2559                 if (file->is_binary)
2560                         fprintf(options->file, "-\t-\t");
2561                 else
2562                         fprintf(options->file,
2563                                 "%"PRIuMAX"\t%"PRIuMAX"\t",
2564                                 file->added, file->deleted);
2565                 if (options->line_termination) {
2566                         fill_print_name(file);
2567                         if (!file->is_renamed)
2568                                 write_name_quoted(file->name, options->file,
2569                                                   options->line_termination);
2570                         else {
2571                                 fputs(file->print_name, options->file);
2572                                 putc(options->line_termination, options->file);
2573                         }
2574                 } else {
2575                         if (file->is_renamed) {
2576                                 putc('\0', options->file);
2577                                 write_name_quoted(file->from_name, options->file, '\0');
2578                         }
2579                         write_name_quoted(file->name, options->file, '\0');
2580                 }
2581         }
2582 }
2583
2584 struct dirstat_file {
2585         const char *name;
2586         unsigned long changed;
2587 };
2588
2589 struct dirstat_dir {
2590         struct dirstat_file *files;
2591         int alloc, nr, permille, cumulative;
2592 };
2593
2594 static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
2595                 unsigned long changed, const char *base, int baselen)
2596 {
2597         unsigned long this_dir = 0;
2598         unsigned int sources = 0;
2599         const char *line_prefix = diff_line_prefix(opt);
2600
2601         while (dir->nr) {
2602                 struct dirstat_file *f = dir->files;
2603                 int namelen = strlen(f->name);
2604                 unsigned long this;
2605                 char *slash;
2606
2607                 if (namelen < baselen)
2608                         break;
2609                 if (memcmp(f->name, base, baselen))
2610                         break;
2611                 slash = strchr(f->name + baselen, '/');
2612                 if (slash) {
2613                         int newbaselen = slash + 1 - f->name;
2614                         this = gather_dirstat(opt, dir, changed, f->name, newbaselen);
2615                         sources++;
2616                 } else {
2617                         this = f->changed;
2618                         dir->files++;
2619                         dir->nr--;
2620                         sources += 2;
2621                 }
2622                 this_dir += this;
2623         }
2624
2625         /*
2626          * We don't report dirstat's for
2627          *  - the top level
2628          *  - or cases where everything came from a single directory
2629          *    under this directory (sources == 1).
2630          */
2631         if (baselen && sources != 1) {
2632                 if (this_dir) {
2633                         int permille = this_dir * 1000 / changed;
2634                         if (permille >= dir->permille) {
2635                                 fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
2636                                         permille / 10, permille % 10, baselen, base);
2637                                 if (!dir->cumulative)
2638                                         return 0;
2639                         }
2640                 }
2641         }
2642         return this_dir;
2643 }
2644
2645 static int dirstat_compare(const void *_a, const void *_b)
2646 {
2647         const struct dirstat_file *a = _a;
2648         const struct dirstat_file *b = _b;
2649         return strcmp(a->name, b->name);
2650 }
2651
2652 static void show_dirstat(struct diff_options *options)
2653 {
2654         int i;
2655         unsigned long changed;
2656         struct dirstat_dir dir;
2657         struct diff_queue_struct *q = &diff_queued_diff;
2658
2659         dir.files = NULL;
2660         dir.alloc = 0;
2661         dir.nr = 0;
2662         dir.permille = options->dirstat_permille;
2663         dir.cumulative = options->flags.dirstat_cumulative;
2664
2665         changed = 0;
2666         for (i = 0; i < q->nr; i++) {
2667                 struct diff_filepair *p = q->queue[i];
2668                 const char *name;
2669                 unsigned long copied, added, damage;
2670                 int content_changed;
2671
2672                 name = p->two->path ? p->two->path : p->one->path;
2673
2674                 if (p->one->oid_valid && p->two->oid_valid)
2675                         content_changed = oidcmp(&p->one->oid, &p->two->oid);
2676                 else
2677                         content_changed = 1;
2678
2679                 if (!content_changed) {
2680                         /*
2681                          * The SHA1 has not changed, so pre-/post-content is
2682                          * identical. We can therefore skip looking at the
2683                          * file contents altogether.
2684                          */
2685                         damage = 0;
2686                         goto found_damage;
2687                 }
2688
2689                 if (options->flags.dirstat_by_file) {
2690                         /*
2691                          * In --dirstat-by-file mode, we don't really need to
2692                          * look at the actual file contents at all.
2693                          * The fact that the SHA1 changed is enough for us to
2694                          * add this file to the list of results
2695                          * (with each file contributing equal damage).
2696                          */
2697                         damage = 1;
2698                         goto found_damage;
2699                 }
2700
2701                 if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
2702                         diff_populate_filespec(p->one, 0);
2703                         diff_populate_filespec(p->two, 0);
2704                         diffcore_count_changes(p->one, p->two, NULL, NULL,
2705                                                &copied, &added);
2706                         diff_free_filespec_data(p->one);
2707                         diff_free_filespec_data(p->two);
2708                 } else if (DIFF_FILE_VALID(p->one)) {
2709                         diff_populate_filespec(p->one, CHECK_SIZE_ONLY);
2710                         copied = added = 0;
2711                         diff_free_filespec_data(p->one);
2712                 } else if (DIFF_FILE_VALID(p->two)) {
2713                         diff_populate_filespec(p->two, CHECK_SIZE_ONLY);
2714                         copied = 0;
2715                         added = p->two->size;
2716                         diff_free_filespec_data(p->two);
2717                 } else
2718                         continue;
2719
2720                 /*
2721                  * Original minus copied is the removed material,
2722                  * added is the new material.  They are both damages
2723                  * made to the preimage.
2724                  * If the resulting damage is zero, we know that
2725                  * diffcore_count_changes() considers the two entries to
2726                  * be identical, but since content_changed is true, we
2727                  * know that there must have been _some_ kind of change,
2728                  * so we force all entries to have damage > 0.
2729                  */
2730                 damage = (p->one->size - copied) + added;
2731                 if (!damage)
2732                         damage = 1;
2733
2734 found_damage:
2735                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
2736                 dir.files[dir.nr].name = name;
2737                 dir.files[dir.nr].changed = damage;
2738                 changed += damage;
2739                 dir.nr++;
2740         }
2741
2742         /* This can happen even with many files, if everything was renames */
2743         if (!changed)
2744                 return;
2745
2746         /* Show all directories with more than x% of the changes */
2747         QSORT(dir.files, dir.nr, dirstat_compare);
2748         gather_dirstat(options, &dir, changed, "", 0);
2749 }
2750
2751 static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
2752 {
2753         int i;
2754         unsigned long changed;
2755         struct dirstat_dir dir;
2756
2757         if (data->nr == 0)
2758                 return;
2759
2760         dir.files = NULL;
2761         dir.alloc = 0;
2762         dir.nr = 0;
2763         dir.permille = options->dirstat_permille;
2764         dir.cumulative = options->flags.dirstat_cumulative;
2765
2766         changed = 0;
2767         for (i = 0; i < data->nr; i++) {
2768                 struct diffstat_file *file = data->files[i];
2769                 unsigned long damage = file->added + file->deleted;
2770                 if (file->is_binary)
2771                         /*
2772                          * binary files counts bytes, not lines. Must find some
2773                          * way to normalize binary bytes vs. textual lines.
2774                          * The following heuristic assumes that there are 64
2775                          * bytes per "line".
2776                          * This is stupid and ugly, but very cheap...
2777                          */
2778                         damage = DIV_ROUND_UP(damage, 64);
2779                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
2780                 dir.files[dir.nr].name = file->name;
2781                 dir.files[dir.nr].changed = damage;
2782                 changed += damage;
2783                 dir.nr++;
2784         }
2785
2786         /* This can happen even with many files, if everything was renames */
2787         if (!changed)
2788                 return;
2789
2790         /* Show all directories with more than x% of the changes */
2791         QSORT(dir.files, dir.nr, dirstat_compare);
2792         gather_dirstat(options, &dir, changed, "", 0);
2793 }
2794
2795 static void free_diffstat_info(struct diffstat_t *diffstat)
2796 {
2797         int i;
2798         for (i = 0; i < diffstat->nr; i++) {
2799                 struct diffstat_file *f = diffstat->files[i];
2800                 if (f->name != f->print_name)
2801                         free(f->print_name);
2802                 free(f->name);
2803                 free(f->from_name);
2804                 free(f);
2805         }
2806         free(diffstat->files);
2807 }
2808
2809 struct checkdiff_t {
2810         const char *filename;
2811         int lineno;
2812         int conflict_marker_size;
2813         struct diff_options *o;
2814         unsigned ws_rule;
2815         unsigned status;
2816 };
2817
2818 static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
2819 {
2820         char firstchar;
2821         int cnt;
2822
2823         if (len < marker_size + 1)
2824                 return 0;
2825         firstchar = line[0];
2826         switch (firstchar) {
2827         case '=': case '>': case '<': case '|':
2828                 break;
2829         default:
2830                 return 0;
2831         }
2832         for (cnt = 1; cnt < marker_size; cnt++)
2833                 if (line[cnt] != firstchar)
2834                         return 0;
2835         /* line[1] thru line[marker_size-1] are same as firstchar */
2836         if (len < marker_size + 1 || !isspace(line[marker_size]))
2837                 return 0;
2838         return 1;
2839 }
2840
2841 static void checkdiff_consume(void *priv, char *line, unsigned long len)
2842 {
2843         struct checkdiff_t *data = priv;
2844         int marker_size = data->conflict_marker_size;
2845         const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
2846         const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
2847         const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
2848         char *err;
2849         const char *line_prefix;
2850
2851         assert(data->o);
2852         line_prefix = diff_line_prefix(data->o);
2853
2854         if (line[0] == '+') {
2855                 unsigned bad;
2856                 data->lineno++;
2857                 if (is_conflict_marker(line + 1, marker_size, len - 1)) {
2858                         data->status |= 1;
2859                         fprintf(data->o->file,
2860                                 "%s%s:%d: leftover conflict marker\n",
2861                                 line_prefix, data->filename, data->lineno);
2862                 }
2863                 bad = ws_check(line + 1, len - 1, data->ws_rule);
2864                 if (!bad)
2865                         return;
2866                 data->status |= bad;
2867                 err = whitespace_error_string(bad);
2868                 fprintf(data->o->file, "%s%s:%d: %s.\n",
2869                         line_prefix, data->filename, data->lineno, err);
2870                 free(err);
2871                 emit_line(data->o, set, reset, line, 1);
2872                 ws_check_emit(line + 1, len - 1, data->ws_rule,
2873                               data->o->file, set, reset, ws);
2874         } else if (line[0] == ' ') {
2875                 data->lineno++;
2876         } else if (line[0] == '@') {
2877                 char *plus = strchr(line, '+');
2878                 if (plus)
2879                         data->lineno = strtol(plus, NULL, 10) - 1;
2880                 else
2881                         die("invalid diff");
2882         }
2883 }
2884
2885 static unsigned char *deflate_it(char *data,
2886                                  unsigned long size,
2887                                  unsigned long *result_size)
2888 {
2889         int bound;
2890         unsigned char *deflated;
2891         git_zstream stream;
2892
2893         git_deflate_init(&stream, zlib_compression_level);
2894         bound = git_deflate_bound(&stream, size);
2895         deflated = xmalloc(bound);
2896         stream.next_out = deflated;
2897         stream.avail_out = bound;
2898
2899         stream.next_in = (unsigned char *)data;
2900         stream.avail_in = size;
2901         while (git_deflate(&stream, Z_FINISH) == Z_OK)
2902                 ; /* nothing */
2903         git_deflate_end(&stream);
2904         *result_size = stream.total_out;
2905         return deflated;
2906 }
2907
2908 static void emit_binary_diff_body(struct diff_options *o,
2909                                   mmfile_t *one, mmfile_t *two)
2910 {
2911         void *cp;
2912         void *delta;
2913         void *deflated;
2914         void *data;
2915         unsigned long orig_size;
2916         unsigned long delta_size;
2917         unsigned long deflate_size;
2918         unsigned long data_size;
2919
2920         /* We could do deflated delta, or we could do just deflated two,
2921          * whichever is smaller.
2922          */
2923         delta = NULL;
2924         deflated = deflate_it(two->ptr, two->size, &deflate_size);
2925         if (one->size && two->size) {
2926                 delta = diff_delta(one->ptr, one->size,
2927                                    two->ptr, two->size,
2928                                    &delta_size, deflate_size);
2929                 if (delta) {
2930                         void *to_free = delta;
2931                         orig_size = delta_size;
2932                         delta = deflate_it(delta, delta_size, &delta_size);
2933                         free(to_free);
2934                 }
2935         }
2936
2937         if (delta && delta_size < deflate_size) {
2938                 char *s = xstrfmt("%lu", orig_size);
2939                 emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_HEADER_DELTA,
2940                                  s, strlen(s), 0);
2941                 free(s);
2942                 free(deflated);
2943                 data = delta;
2944                 data_size = delta_size;
2945         } else {
2946                 char *s = xstrfmt("%lu", two->size);
2947                 emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_HEADER_LITERAL,
2948                                  s, strlen(s), 0);
2949                 free(s);
2950                 free(delta);
2951                 data = deflated;
2952                 data_size = deflate_size;
2953         }
2954
2955         /* emit data encoded in base85 */
2956         cp = data;
2957         while (data_size) {
2958                 int len;
2959                 int bytes = (52 < data_size) ? 52 : data_size;
2960                 char line[71];
2961                 data_size -= bytes;
2962                 if (bytes <= 26)
2963                         line[0] = bytes + 'A' - 1;
2964                 else
2965                         line[0] = bytes - 26 + 'a' - 1;
2966                 encode_85(line + 1, cp, bytes);
2967                 cp = (char *) cp + bytes;
2968
2969                 len = strlen(line);
2970                 line[len++] = '\n';
2971                 line[len] = '\0';
2972
2973                 emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_BODY,
2974                                  line, len, 0);
2975         }
2976         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_FOOTER, NULL, 0, 0);
2977         free(data);
2978 }
2979
2980 static void emit_binary_diff(struct diff_options *o,
2981                              mmfile_t *one, mmfile_t *two)
2982 {
2983         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_HEADER, NULL, 0, 0);
2984         emit_binary_diff_body(o, one, two);
2985         emit_binary_diff_body(o, two, one);
2986 }
2987
2988 int diff_filespec_is_binary(struct diff_filespec *one)
2989 {
2990         if (one->is_binary == -1) {
2991                 diff_filespec_load_driver(one);
2992                 if (one->driver->binary != -1)
2993                         one->is_binary = one->driver->binary;
2994                 else {
2995                         if (!one->data && DIFF_FILE_VALID(one))
2996                                 diff_populate_filespec(one, CHECK_BINARY);
2997                         if (one->is_binary == -1 && one->data)
2998                                 one->is_binary = buffer_is_binary(one->data,
2999                                                 one->size);
3000                         if (one->is_binary == -1)
3001                                 one->is_binary = 0;
3002                 }
3003         }
3004         return one->is_binary;
3005 }
3006
3007 static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
3008 {
3009         diff_filespec_load_driver(one);
3010         return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
3011 }
3012
3013 void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
3014 {
3015         if (!options->a_prefix)
3016                 options->a_prefix = a;
3017         if (!options->b_prefix)
3018                 options->b_prefix = b;
3019 }
3020
3021 struct userdiff_driver *get_textconv(struct diff_filespec *one)
3022 {
3023         if (!DIFF_FILE_VALID(one))
3024                 return NULL;
3025
3026         diff_filespec_load_driver(one);
3027         return userdiff_get_textconv(one->driver);
3028 }
3029
3030 static void builtin_diff(const char *name_a,
3031                          const char *name_b,
3032                          struct diff_filespec *one,
3033                          struct diff_filespec *two,
3034                          const char *xfrm_msg,
3035                          int must_show_header,
3036                          struct diff_options *o,
3037                          int complete_rewrite)
3038 {
3039         mmfile_t mf1, mf2;
3040         const char *lbl[2];
3041         char *a_one, *b_two;
3042         const char *meta = diff_get_color_opt(o, DIFF_METAINFO);
3043         const char *reset = diff_get_color_opt(o, DIFF_RESET);
3044         const char *a_prefix, *b_prefix;
3045         struct userdiff_driver *textconv_one = NULL;
3046         struct userdiff_driver *textconv_two = NULL;
3047         struct strbuf header = STRBUF_INIT;
3048         const char *line_prefix = diff_line_prefix(o);
3049
3050         diff_set_mnemonic_prefix(o, "a/", "b/");
3051         if (o->flags.reverse_diff) {
3052                 a_prefix = o->b_prefix;
3053                 b_prefix = o->a_prefix;
3054         } else {
3055                 a_prefix = o->a_prefix;
3056                 b_prefix = o->b_prefix;
3057         }
3058
3059         if (o->submodule_format == DIFF_SUBMODULE_LOG &&
3060             (!one->mode || S_ISGITLINK(one->mode)) &&
3061             (!two->mode || S_ISGITLINK(two->mode))) {
3062                 show_submodule_summary(o, one->path ? one->path : two->path,
3063                                 &one->oid, &two->oid,
3064                                 two->dirty_submodule);
3065                 return;
3066         } else if (o->submodule_format == DIFF_SUBMODULE_INLINE_DIFF &&
3067                    (!one->mode || S_ISGITLINK(one->mode)) &&
3068                    (!two->mode || S_ISGITLINK(two->mode))) {
3069                 show_submodule_inline_diff(o, one->path ? one->path : two->path,
3070                                 &one->oid, &two->oid,
3071                                 two->dirty_submodule);
3072                 return;
3073         }
3074
3075         if (o->flags.allow_textconv) {
3076                 textconv_one = get_textconv(one);
3077                 textconv_two = get_textconv(two);
3078         }
3079
3080         /* Never use a non-valid filename anywhere if at all possible */
3081         name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
3082         name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
3083
3084         a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
3085         b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
3086         lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
3087         lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
3088         strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, meta, a_one, b_two, reset);
3089         if (lbl[0][0] == '/') {
3090                 /* /dev/null */
3091                 strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, meta, two->mode, reset);
3092                 if (xfrm_msg)
3093                         strbuf_addstr(&header, xfrm_msg);
3094                 must_show_header = 1;
3095         }
3096         else if (lbl[1][0] == '/') {
3097                 strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, meta, one->mode, reset);
3098                 if (xfrm_msg)
3099                         strbuf_addstr(&header, xfrm_msg);
3100                 must_show_header = 1;
3101         }
3102         else {
3103                 if (one->mode != two->mode) {
3104                         strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, meta, one->mode, reset);
3105                         strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, meta, two->mode, reset);
3106                         must_show_header = 1;
3107                 }
3108                 if (xfrm_msg)
3109                         strbuf_addstr(&header, xfrm_msg);
3110
3111                 /*
3112                  * we do not run diff between different kind
3113                  * of objects.
3114                  */
3115                 if ((one->mode ^ two->mode) & S_IFMT)
3116                         goto free_ab_and_return;
3117                 if (complete_rewrite &&
3118                     (textconv_one || !diff_filespec_is_binary(one)) &&
3119                     (textconv_two || !diff_filespec_is_binary(two))) {
3120                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3121                                          header.buf, header.len, 0);
3122                         strbuf_reset(&header);
3123                         emit_rewrite_diff(name_a, name_b, one, two,
3124                                                 textconv_one, textconv_two, o);
3125                         o->found_changes = 1;
3126                         goto free_ab_and_return;
3127                 }
3128         }
3129
3130         if (o->irreversible_delete && lbl[1][0] == '/') {
3131                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER, header.buf,
3132                                  header.len, 0);
3133                 strbuf_reset(&header);
3134                 goto free_ab_and_return;
3135         } else if (!o->flags.text &&
3136             ( (!textconv_one && diff_filespec_is_binary(one)) ||
3137               (!textconv_two && diff_filespec_is_binary(two)) )) {
3138                 struct strbuf sb = STRBUF_INIT;
3139                 if (!one->data && !two->data &&
3140                     S_ISREG(one->mode) && S_ISREG(two->mode) &&
3141                     !o->flags.binary) {
3142                         if (!oidcmp(&one->oid, &two->oid)) {
3143                                 if (must_show_header)
3144                                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3145                                                          header.buf, header.len,
3146                                                          0);
3147                                 goto free_ab_and_return;
3148                         }
3149                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3150                                          header.buf, header.len, 0);
3151                         strbuf_addf(&sb, "%sBinary files %s and %s differ\n",
3152                                     diff_line_prefix(o), lbl[0], lbl[1]);
3153                         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_FILES,
3154                                          sb.buf, sb.len, 0);
3155                         strbuf_release(&sb);
3156                         goto free_ab_and_return;
3157                 }
3158                 if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
3159                         die("unable to read files to diff");
3160                 /* Quite common confusing case */
3161                 if (mf1.size == mf2.size &&
3162                     !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
3163                         if (must_show_header)
3164                                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3165                                                  header.buf, header.len, 0);
3166                         goto free_ab_and_return;
3167                 }
3168                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER, header.buf, header.len, 0);
3169                 strbuf_reset(&header);
3170                 if (o->flags.binary)
3171                         emit_binary_diff(o, &mf1, &mf2);
3172                 else {
3173                         strbuf_addf(&sb, "%sBinary files %s and %s differ\n",
3174                                     diff_line_prefix(o), lbl[0], lbl[1]);
3175                         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_FILES,
3176                                          sb.buf, sb.len, 0);
3177                         strbuf_release(&sb);
3178                 }
3179                 o->found_changes = 1;
3180         } else {
3181                 /* Crazy xdl interfaces.. */
3182                 const char *diffopts = getenv("GIT_DIFF_OPTS");
3183                 const char *v;
3184                 xpparam_t xpp;
3185                 xdemitconf_t xecfg;
3186                 struct emit_callback ecbdata;
3187                 const struct userdiff_funcname *pe;
3188
3189                 if (must_show_header) {
3190                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3191                                          header.buf, header.len, 0);
3192                         strbuf_reset(&header);
3193                 }
3194
3195                 mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
3196                 mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
3197
3198                 pe = diff_funcname_pattern(one);
3199                 if (!pe)
3200                         pe = diff_funcname_pattern(two);
3201
3202                 memset(&xpp, 0, sizeof(xpp));
3203                 memset(&xecfg, 0, sizeof(xecfg));
3204                 memset(&ecbdata, 0, sizeof(ecbdata));
3205                 ecbdata.label_path = lbl;
3206                 ecbdata.color_diff = want_color(o->use_color);
3207                 ecbdata.ws_rule = whitespace_rule(name_b);
3208                 if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
3209                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
3210                 ecbdata.opt = o;
3211                 ecbdata.header = header.len ? &header : NULL;
3212                 xpp.flags = o->xdl_opts;
3213                 xecfg.ctxlen = o->context;
3214                 xecfg.interhunkctxlen = o->interhunkcontext;
3215                 xecfg.flags = XDL_EMIT_FUNCNAMES;
3216                 if (o->flags.funccontext)
3217                         xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
3218                 if (pe)
3219                         xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
3220                 if (!diffopts)
3221                         ;
3222                 else if (skip_prefix(diffopts, "--unified=", &v))
3223                         xecfg.ctxlen = strtoul(v, NULL, 10);
3224                 else if (skip_prefix(diffopts, "-u", &v))
3225                         xecfg.ctxlen = strtoul(v, NULL, 10);
3226                 if (o->word_diff)
3227                         init_diff_words_data(&ecbdata, o, one, two);
3228                 if (xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
3229                                   &xpp, &xecfg))
3230                         die("unable to generate diff for %s", one->path);
3231                 if (o->word_diff)
3232                         free_diff_words_data(&ecbdata);
3233                 if (textconv_one)
3234                         free(mf1.ptr);
3235                 if (textconv_two)
3236                         free(mf2.ptr);
3237                 xdiff_clear_find_func(&xecfg);
3238         }
3239
3240  free_ab_and_return:
3241         strbuf_release(&header);
3242         diff_free_filespec_data(one);
3243         diff_free_filespec_data(two);
3244         free(a_one);
3245         free(b_two);
3246         return;
3247 }
3248
3249 static void builtin_diffstat(const char *name_a, const char *name_b,
3250                              struct diff_filespec *one,
3251                              struct diff_filespec *two,
3252                              struct diffstat_t *diffstat,
3253                              struct diff_options *o,
3254                              struct diff_filepair *p)
3255 {
3256         mmfile_t mf1, mf2;
3257         struct diffstat_file *data;
3258         int same_contents;
3259         int complete_rewrite = 0;
3260
3261         if (!DIFF_PAIR_UNMERGED(p)) {
3262                 if (p->status == DIFF_STATUS_MODIFIED && p->score)
3263                         complete_rewrite = 1;
3264         }
3265
3266         data = diffstat_add(diffstat, name_a, name_b);
3267         data->is_interesting = p->status != DIFF_STATUS_UNKNOWN;
3268
3269         if (!one || !two) {
3270                 data->is_unmerged = 1;
3271                 return;
3272         }
3273
3274         same_contents = !oidcmp(&one->oid, &two->oid);
3275
3276         if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
3277                 data->is_binary = 1;
3278                 if (same_contents) {
3279                         data->added = 0;
3280                         data->deleted = 0;
3281                 } else {
3282                         data->added = diff_filespec_size(two);
3283                         data->deleted = diff_filespec_size(one);
3284                 }
3285         }
3286
3287         else if (complete_rewrite) {
3288                 diff_populate_filespec(one, 0);
3289                 diff_populate_filespec(two, 0);
3290                 data->deleted = count_lines(one->data, one->size);
3291                 data->added = count_lines(two->data, two->size);
3292         }
3293
3294         else if (!same_contents) {
3295                 /* Crazy xdl interfaces.. */
3296                 xpparam_t xpp;
3297                 xdemitconf_t xecfg;
3298
3299                 if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
3300                         die("unable to read files to diff");
3301
3302                 memset(&xpp, 0, sizeof(xpp));
3303                 memset(&xecfg, 0, sizeof(xecfg));
3304                 xpp.flags = o->xdl_opts;
3305                 xecfg.ctxlen = o->context;
3306                 xecfg.interhunkctxlen = o->interhunkcontext;
3307                 if (xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
3308                                   &xpp, &xecfg))
3309                         die("unable to generate diffstat for %s", one->path);
3310         }
3311
3312         diff_free_filespec_data(one);
3313         diff_free_filespec_data(two);
3314 }
3315
3316 static void builtin_checkdiff(const char *name_a, const char *name_b,
3317                               const char *attr_path,
3318                               struct diff_filespec *one,
3319                               struct diff_filespec *two,
3320                               struct diff_options *o)
3321 {
3322         mmfile_t mf1, mf2;
3323         struct checkdiff_t data;
3324
3325         if (!two)
3326                 return;
3327
3328         memset(&data, 0, sizeof(data));
3329         data.filename = name_b ? name_b : name_a;
3330         data.lineno = 0;
3331         data.o = o;
3332         data.ws_rule = whitespace_rule(attr_path);
3333         data.conflict_marker_size = ll_merge_marker_size(attr_path);
3334
3335         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
3336                 die("unable to read files to diff");
3337
3338         /*
3339          * All the other codepaths check both sides, but not checking
3340          * the "old" side here is deliberate.  We are checking the newly
3341          * introduced changes, and as long as the "new" side is text, we
3342          * can and should check what it introduces.
3343          */
3344         if (diff_filespec_is_binary(two))
3345                 goto free_and_return;
3346         else {
3347                 /* Crazy xdl interfaces.. */
3348                 xpparam_t xpp;
3349                 xdemitconf_t xecfg;
3350
3351                 memset(&xpp, 0, sizeof(xpp));
3352                 memset(&xecfg, 0, sizeof(xecfg));
3353                 xecfg.ctxlen = 1; /* at least one context line */
3354                 xpp.flags = 0;
3355                 if (xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
3356                                   &xpp, &xecfg))
3357                         die("unable to generate checkdiff for %s", one->path);
3358
3359                 if (data.ws_rule & WS_BLANK_AT_EOF) {
3360                         struct emit_callback ecbdata;
3361                         int blank_at_eof;
3362
3363                         ecbdata.ws_rule = data.ws_rule;
3364                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
3365                         blank_at_eof = ecbdata.blank_at_eof_in_postimage;
3366
3367                         if (blank_at_eof) {
3368                                 static char *err;
3369                                 if (!err)
3370                                         err = whitespace_error_string(WS_BLANK_AT_EOF);
3371                                 fprintf(o->file, "%s:%d: %s.\n",
3372                                         data.filename, blank_at_eof, err);
3373                                 data.status = 1; /* report errors */
3374                         }
3375                 }
3376         }
3377  free_and_return:
3378         diff_free_filespec_data(one);
3379         diff_free_filespec_data(two);
3380         if (data.status)
3381                 o->flags.check_failed = 1;
3382 }
3383
3384 struct diff_filespec *alloc_filespec(const char *path)
3385 {
3386         struct diff_filespec *spec;
3387
3388         FLEXPTR_ALLOC_STR(spec, path, path);
3389         spec->count = 1;
3390         spec->is_binary = -1;
3391         return spec;
3392 }
3393
3394 void free_filespec(struct diff_filespec *spec)
3395 {
3396         if (!--spec->count) {
3397                 diff_free_filespec_data(spec);
3398                 free(spec);
3399         }
3400 }
3401
3402 void fill_filespec(struct diff_filespec *spec, const struct object_id *oid,
3403                    int oid_valid, unsigned short mode)
3404 {
3405         if (mode) {
3406                 spec->mode = canon_mode(mode);
3407                 oidcpy(&spec->oid, oid);
3408                 spec->oid_valid = oid_valid;
3409         }
3410 }
3411
3412 /*
3413  * Given a name and sha1 pair, if the index tells us the file in
3414  * the work tree has that object contents, return true, so that
3415  * prepare_temp_file() does not have to inflate and extract.
3416  */
3417 static int reuse_worktree_file(const char *name, const struct object_id *oid, int want_file)
3418 {
3419         const struct cache_entry *ce;
3420         struct stat st;
3421         int pos, len;
3422
3423         /*
3424          * We do not read the cache ourselves here, because the
3425          * benchmark with my previous version that always reads cache
3426          * shows that it makes things worse for diff-tree comparing
3427          * two linux-2.6 kernel trees in an already checked out work
3428          * tree.  This is because most diff-tree comparisons deal with
3429          * only a small number of files, while reading the cache is
3430          * expensive for a large project, and its cost outweighs the
3431          * savings we get by not inflating the object to a temporary
3432          * file.  Practically, this code only helps when we are used
3433          * by diff-cache --cached, which does read the cache before
3434          * calling us.
3435          */
3436         if (!active_cache)
3437                 return 0;
3438
3439         /* We want to avoid the working directory if our caller
3440          * doesn't need the data in a normal file, this system
3441          * is rather slow with its stat/open/mmap/close syscalls,
3442          * and the object is contained in a pack file.  The pack
3443          * is probably already open and will be faster to obtain
3444          * the data through than the working directory.  Loose
3445          * objects however would tend to be slower as they need
3446          * to be individually opened and inflated.
3447          */
3448         if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(oid->hash))
3449                 return 0;
3450
3451         /*
3452          * Similarly, if we'd have to convert the file contents anyway, that
3453          * makes the optimization not worthwhile.
3454          */
3455         if (!want_file && would_convert_to_git(&the_index, name))
3456                 return 0;
3457
3458         len = strlen(name);
3459         pos = cache_name_pos(name, len);
3460         if (pos < 0)
3461                 return 0;
3462         ce = active_cache[pos];
3463
3464         /*
3465          * This is not the sha1 we are looking for, or
3466          * unreusable because it is not a regular file.
3467          */
3468         if (oidcmp(oid, &ce->oid) || !S_ISREG(ce->ce_mode))
3469                 return 0;
3470
3471         /*
3472          * If ce is marked as "assume unchanged", there is no
3473          * guarantee that work tree matches what we are looking for.
3474          */
3475         if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
3476                 return 0;
3477
3478         /*
3479          * If ce matches the file in the work tree, we can reuse it.
3480          */
3481         if (ce_uptodate(ce) ||
3482             (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
3483                 return 1;
3484
3485         return 0;
3486 }
3487
3488 static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
3489 {
3490         struct strbuf buf = STRBUF_INIT;
3491         char *dirty = "";
3492
3493         /* Are we looking at the work tree? */
3494         if (s->dirty_submodule)
3495                 dirty = "-dirty";
3496
3497         strbuf_addf(&buf, "Subproject commit %s%s\n",
3498                     oid_to_hex(&s->oid), dirty);
3499         s->size = buf.len;
3500         if (size_only) {
3501                 s->data = NULL;
3502                 strbuf_release(&buf);
3503         } else {
3504                 s->data = strbuf_detach(&buf, NULL);
3505                 s->should_free = 1;
3506         }
3507         return 0;
3508 }
3509
3510 /*
3511  * While doing rename detection and pickaxe operation, we may need to
3512  * grab the data for the blob (or file) for our own in-core comparison.
3513  * diff_filespec has data and size fields for this purpose.
3514  */
3515 int diff_populate_filespec(struct diff_filespec *s, unsigned int flags)
3516 {
3517         int size_only = flags & CHECK_SIZE_ONLY;
3518         int err = 0;
3519         /*
3520          * demote FAIL to WARN to allow inspecting the situation
3521          * instead of refusing.
3522          */
3523         enum safe_crlf crlf_warn = (safe_crlf == SAFE_CRLF_FAIL
3524                                     ? SAFE_CRLF_WARN
3525                                     : safe_crlf);
3526
3527         if (!DIFF_FILE_VALID(s))
3528                 die("internal error: asking to populate invalid file.");
3529         if (S_ISDIR(s->mode))
3530                 return -1;
3531
3532         if (s->data)
3533                 return 0;
3534
3535         if (size_only && 0 < s->size)
3536                 return 0;
3537
3538         if (S_ISGITLINK(s->mode))
3539                 return diff_populate_gitlink(s, size_only);
3540
3541         if (!s->oid_valid ||
3542             reuse_worktree_file(s->path, &s->oid, 0)) {
3543                 struct strbuf buf = STRBUF_INIT;
3544                 struct stat st;
3545                 int fd;
3546
3547                 if (lstat(s->path, &st) < 0) {
3548                 err_empty:
3549                         err = -1;
3550                 empty:
3551                         s->data = (char *)"";
3552                         s->size = 0;
3553                         return err;
3554                 }
3555                 s->size = xsize_t(st.st_size);
3556                 if (!s->size)
3557                         goto empty;
3558                 if (S_ISLNK(st.st_mode)) {
3559                         struct strbuf sb = STRBUF_INIT;
3560
3561                         if (strbuf_readlink(&sb, s->path, s->size))
3562                                 goto err_empty;
3563                         s->size = sb.len;
3564                         s->data = strbuf_detach(&sb, NULL);
3565                         s->should_free = 1;
3566                         return 0;
3567                 }
3568
3569                 /*
3570                  * Even if the caller would be happy with getting
3571                  * only the size, we cannot return early at this
3572                  * point if the path requires us to run the content
3573                  * conversion.
3574                  */
3575                 if (size_only && !would_convert_to_git(&the_index, s->path))
3576                         return 0;
3577
3578                 /*
3579                  * Note: this check uses xsize_t(st.st_size) that may
3580                  * not be the true size of the blob after it goes
3581                  * through convert_to_git().  This may not strictly be
3582                  * correct, but the whole point of big_file_threshold
3583                  * and is_binary check being that we want to avoid
3584                  * opening the file and inspecting the contents, this
3585                  * is probably fine.
3586                  */
3587                 if ((flags & CHECK_BINARY) &&
3588                     s->size > big_file_threshold && s->is_binary == -1) {
3589                         s->is_binary = 1;
3590                         return 0;
3591                 }
3592                 fd = open(s->path, O_RDONLY);
3593                 if (fd < 0)
3594                         goto err_empty;
3595                 s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
3596                 close(fd);
3597                 s->should_munmap = 1;
3598
3599                 /*
3600                  * Convert from working tree format to canonical git format
3601                  */
3602                 if (convert_to_git(&the_index, s->path, s->data, s->size, &buf, crlf_warn)) {
3603                         size_t size = 0;
3604                         munmap(s->data, s->size);
3605                         s->should_munmap = 0;
3606                         s->data = strbuf_detach(&buf, &size);
3607                         s->size = size;
3608                         s->should_free = 1;
3609                 }
3610         }
3611         else {
3612                 enum object_type type;
3613                 if (size_only || (flags & CHECK_BINARY)) {
3614                         type = sha1_object_info(s->oid.hash, &s->size);
3615                         if (type < 0)
3616                                 die("unable to read %s",
3617                                     oid_to_hex(&s->oid));
3618                         if (size_only)
3619                                 return 0;
3620                         if (s->size > big_file_threshold && s->is_binary == -1) {
3621                                 s->is_binary = 1;
3622                                 return 0;
3623                         }
3624                 }
3625                 s->data = read_sha1_file(s->oid.hash, &type, &s->size);
3626                 if (!s->data)
3627                         die("unable to read %s", oid_to_hex(&s->oid));
3628                 s->should_free = 1;
3629         }
3630         return 0;
3631 }
3632
3633 void diff_free_filespec_blob(struct diff_filespec *s)
3634 {
3635         if (s->should_free)
3636                 free(s->data);
3637         else if (s->should_munmap)
3638                 munmap(s->data, s->size);
3639
3640         if (s->should_free || s->should_munmap) {
3641                 s->should_free = s->should_munmap = 0;
3642                 s->data = NULL;
3643         }
3644 }
3645
3646 void diff_free_filespec_data(struct diff_filespec *s)
3647 {
3648         diff_free_filespec_blob(s);
3649         FREE_AND_NULL(s->cnt_data);
3650 }
3651
3652 static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
3653                            void *blob,
3654                            unsigned long size,
3655                            const struct object_id *oid,
3656                            int mode)
3657 {
3658         struct strbuf buf = STRBUF_INIT;
3659         struct strbuf template = STRBUF_INIT;
3660         char *path_dup = xstrdup(path);
3661         const char *base = basename(path_dup);
3662
3663         /* Generate "XXXXXX_basename.ext" */
3664         strbuf_addstr(&template, "XXXXXX_");
3665         strbuf_addstr(&template, base);
3666
3667         temp->tempfile = mks_tempfile_ts(template.buf, strlen(base) + 1);
3668         if (!temp->tempfile)
3669                 die_errno("unable to create temp-file");
3670         if (convert_to_working_tree(path,
3671                         (const char *)blob, (size_t)size, &buf)) {
3672                 blob = buf.buf;
3673                 size = buf.len;
3674         }
3675         if (write_in_full(temp->tempfile->fd, blob, size) < 0 ||
3676             close_tempfile_gently(temp->tempfile))
3677                 die_errno("unable to write temp-file");
3678         temp->name = get_tempfile_path(temp->tempfile);
3679         oid_to_hex_r(temp->hex, oid);
3680         xsnprintf(temp->mode, sizeof(temp->mode), "%06o", mode);
3681         strbuf_release(&buf);
3682         strbuf_release(&template);
3683         free(path_dup);
3684 }
3685
3686 static struct diff_tempfile *prepare_temp_file(const char *name,
3687                 struct diff_filespec *one)
3688 {
3689         struct diff_tempfile *temp = claim_diff_tempfile();
3690
3691         if (!DIFF_FILE_VALID(one)) {
3692         not_a_valid_file:
3693                 /* A '-' entry produces this for file-2, and
3694                  * a '+' entry produces this for file-1.
3695                  */
3696                 temp->name = "/dev/null";
3697                 xsnprintf(temp->hex, sizeof(temp->hex), ".");
3698                 xsnprintf(temp->mode, sizeof(temp->mode), ".");
3699                 return temp;
3700         }
3701
3702         if (!S_ISGITLINK(one->mode) &&
3703             (!one->oid_valid ||
3704              reuse_worktree_file(name, &one->oid, 1))) {
3705                 struct stat st;
3706                 if (lstat(name, &st) < 0) {
3707                         if (errno == ENOENT)
3708                                 goto not_a_valid_file;
3709                         die_errno("stat(%s)", name);
3710                 }
3711                 if (S_ISLNK(st.st_mode)) {
3712                         struct strbuf sb = STRBUF_INIT;
3713                         if (strbuf_readlink(&sb, name, st.st_size) < 0)
3714                                 die_errno("readlink(%s)", name);
3715                         prep_temp_blob(name, temp, sb.buf, sb.len,
3716                                        (one->oid_valid ?
3717                                         &one->oid : &null_oid),
3718                                        (one->oid_valid ?
3719                                         one->mode : S_IFLNK));
3720                         strbuf_release(&sb);
3721                 }
3722                 else {
3723                         /* we can borrow from the file in the work tree */
3724                         temp->name = name;
3725                         if (!one->oid_valid)
3726                                 oid_to_hex_r(temp->hex, &null_oid);
3727                         else
3728                                 oid_to_hex_r(temp->hex, &one->oid);
3729                         /* Even though we may sometimes borrow the
3730                          * contents from the work tree, we always want
3731                          * one->mode.  mode is trustworthy even when
3732                          * !(one->oid_valid), as long as
3733                          * DIFF_FILE_VALID(one).
3734                          */
3735                         xsnprintf(temp->mode, sizeof(temp->mode), "%06o", one->mode);
3736                 }
3737                 return temp;
3738         }
3739         else {
3740                 if (diff_populate_filespec(one, 0))
3741                         die("cannot read data blob for %s", one->path);
3742                 prep_temp_blob(name, temp, one->data, one->size,
3743                                &one->oid, one->mode);
3744         }
3745         return temp;
3746 }
3747
3748 static void add_external_diff_name(struct argv_array *argv,
3749                                    const char *name,
3750                                    struct diff_filespec *df)
3751 {
3752         struct diff_tempfile *temp = prepare_temp_file(name, df);
3753         argv_array_push(argv, temp->name);
3754         argv_array_push(argv, temp->hex);
3755         argv_array_push(argv, temp->mode);
3756 }
3757
3758 /* An external diff command takes:
3759  *
3760  * diff-cmd name infile1 infile1-sha1 infile1-mode \
3761  *               infile2 infile2-sha1 infile2-mode [ rename-to ]
3762  *
3763  */
3764 static void run_external_diff(const char *pgm,
3765                               const char *name,
3766                               const char *other,
3767                               struct diff_filespec *one,
3768                               struct diff_filespec *two,
3769                               const char *xfrm_msg,
3770                               int complete_rewrite,
3771                               struct diff_options *o)
3772 {
3773         struct argv_array argv = ARGV_ARRAY_INIT;
3774         struct argv_array env = ARGV_ARRAY_INIT;
3775         struct diff_queue_struct *q = &diff_queued_diff;
3776
3777         argv_array_push(&argv, pgm);
3778         argv_array_push(&argv, name);
3779
3780         if (one && two) {
3781                 add_external_diff_name(&argv, name, one);
3782                 if (!other)
3783                         add_external_diff_name(&argv, name, two);
3784                 else {
3785                         add_external_diff_name(&argv, other, two);
3786                         argv_array_push(&argv, other);
3787                         argv_array_push(&argv, xfrm_msg);
3788                 }
3789         }
3790
3791         argv_array_pushf(&env, "GIT_DIFF_PATH_COUNTER=%d", ++o->diff_path_counter);
3792         argv_array_pushf(&env, "GIT_DIFF_PATH_TOTAL=%d", q->nr);
3793
3794         if (run_command_v_opt_cd_env(argv.argv, RUN_USING_SHELL, NULL, env.argv))
3795                 die(_("external diff died, stopping at %s"), name);
3796
3797         remove_tempfile();
3798         argv_array_clear(&argv);
3799         argv_array_clear(&env);
3800 }
3801
3802 static int similarity_index(struct diff_filepair *p)
3803 {
3804         return p->score * 100 / MAX_SCORE;
3805 }
3806
3807 static const char *diff_abbrev_oid(const struct object_id *oid, int abbrev)
3808 {
3809         if (startup_info->have_repository)
3810                 return find_unique_abbrev(oid->hash, abbrev);
3811         else {
3812                 char *hex = oid_to_hex(oid);
3813                 if (abbrev < 0)
3814                         abbrev = FALLBACK_DEFAULT_ABBREV;
3815                 if (abbrev > GIT_SHA1_HEXSZ)
3816                         die("BUG: oid abbreviation out of range: %d", abbrev);
3817                 if (abbrev)
3818                         hex[abbrev] = '\0';
3819                 return hex;
3820         }
3821 }
3822
3823 static void fill_metainfo(struct strbuf *msg,
3824                           const char *name,
3825                           const char *other,
3826                           struct diff_filespec *one,
3827                           struct diff_filespec *two,
3828                           struct diff_options *o,
3829                           struct diff_filepair *p,
3830                           int *must_show_header,
3831                           int use_color)
3832 {
3833         const char *set = diff_get_color(use_color, DIFF_METAINFO);
3834         const char *reset = diff_get_color(use_color, DIFF_RESET);
3835         const char *line_prefix = diff_line_prefix(o);
3836
3837         *must_show_header = 1;
3838         strbuf_init(msg, PATH_MAX * 2 + 300);
3839         switch (p->status) {
3840         case DIFF_STATUS_COPIED:
3841                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
3842                             line_prefix, set, similarity_index(p));
3843                 strbuf_addf(msg, "%s\n%s%scopy from ",
3844                             reset,  line_prefix, set);
3845                 quote_c_style(name, msg, NULL, 0);
3846                 strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
3847                 quote_c_style(other, msg, NULL, 0);
3848                 strbuf_addf(msg, "%s\n", reset);
3849                 break;
3850         case DIFF_STATUS_RENAMED:
3851                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
3852                             line_prefix, set, similarity_index(p));
3853                 strbuf_addf(msg, "%s\n%s%srename from ",
3854                             reset, line_prefix, set);
3855                 quote_c_style(name, msg, NULL, 0);
3856                 strbuf_addf(msg, "%s\n%s%srename to ",
3857                             reset, line_prefix, set);
3858                 quote_c_style(other, msg, NULL, 0);
3859                 strbuf_addf(msg, "%s\n", reset);
3860                 break;
3861         case DIFF_STATUS_MODIFIED:
3862                 if (p->score) {
3863                         strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
3864                                     line_prefix,
3865                                     set, similarity_index(p), reset);
3866                         break;
3867                 }
3868                 /* fallthru */
3869         default:
3870                 *must_show_header = 0;
3871         }
3872         if (one && two && oidcmp(&one->oid, &two->oid)) {
3873                 int abbrev = o->flags.full_index ? 40 : DEFAULT_ABBREV;
3874
3875                 if (o->flags.binary) {
3876                         mmfile_t mf;
3877                         if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
3878                             (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
3879                                 abbrev = 40;
3880                 }
3881                 strbuf_addf(msg, "%s%sindex %s..%s", line_prefix, set,
3882                             diff_abbrev_oid(&one->oid, abbrev),
3883                             diff_abbrev_oid(&two->oid, abbrev));
3884                 if (one->mode == two->mode)
3885                         strbuf_addf(msg, " %06o", one->mode);
3886                 strbuf_addf(msg, "%s\n", reset);
3887         }
3888 }
3889
3890 static void run_diff_cmd(const char *pgm,
3891                          const char *name,
3892                          const char *other,
3893                          const char *attr_path,
3894                          struct diff_filespec *one,
3895                          struct diff_filespec *two,
3896                          struct strbuf *msg,
3897                          struct diff_options *o,
3898                          struct diff_filepair *p)
3899 {
3900         const char *xfrm_msg = NULL;
3901         int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
3902         int must_show_header = 0;
3903
3904
3905         if (o->flags.allow_external) {
3906                 struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
3907                 if (drv && drv->external)
3908                         pgm = drv->external;
3909         }
3910
3911         if (msg) {
3912                 /*
3913                  * don't use colors when the header is intended for an
3914                  * external diff driver
3915                  */
3916                 fill_metainfo(msg, name, other, one, two, o, p,
3917                               &must_show_header,
3918                               want_color(o->use_color) && !pgm);
3919                 xfrm_msg = msg->len ? msg->buf : NULL;
3920         }
3921
3922         if (pgm) {
3923                 run_external_diff(pgm, name, other, one, two, xfrm_msg,
3924                                   complete_rewrite, o);
3925                 return;
3926         }
3927         if (one && two)
3928                 builtin_diff(name, other ? other : name,
3929                              one, two, xfrm_msg, must_show_header,
3930                              o, complete_rewrite);
3931         else
3932                 fprintf(o->file, "* Unmerged path %s\n", name);
3933 }
3934
3935 static void diff_fill_oid_info(struct diff_filespec *one)
3936 {
3937         if (DIFF_FILE_VALID(one)) {
3938                 if (!one->oid_valid) {
3939                         struct stat st;
3940                         if (one->is_stdin) {
3941                                 oidclr(&one->oid);
3942                                 return;
3943                         }
3944                         if (lstat(one->path, &st) < 0)
3945                                 die_errno("stat '%s'", one->path);
3946                         if (index_path(&one->oid, one->path, &st, 0))
3947                                 die("cannot hash %s", one->path);
3948                 }
3949         }
3950         else
3951                 oidclr(&one->oid);
3952 }
3953
3954 static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
3955 {
3956         /* Strip the prefix but do not molest /dev/null and absolute paths */
3957         if (*namep && **namep != '/') {
3958                 *namep += prefix_length;
3959                 if (**namep == '/')
3960                         ++*namep;
3961         }
3962         if (*otherp && **otherp != '/') {
3963                 *otherp += prefix_length;
3964                 if (**otherp == '/')
3965                         ++*otherp;
3966         }
3967 }
3968
3969 static void run_diff(struct diff_filepair *p, struct diff_options *o)
3970 {
3971         const char *pgm = external_diff();
3972         struct strbuf msg;
3973         struct diff_filespec *one = p->one;
3974         struct diff_filespec *two = p->two;
3975         const char *name;
3976         const char *other;
3977         const char *attr_path;
3978
3979         name  = one->path;
3980         other = (strcmp(name, two->path) ? two->path : NULL);
3981         attr_path = name;
3982         if (o->prefix_length)
3983                 strip_prefix(o->prefix_length, &name, &other);
3984
3985         if (!o->flags.allow_external)
3986                 pgm = NULL;
3987
3988         if (DIFF_PAIR_UNMERGED(p)) {
3989                 run_diff_cmd(pgm, name, NULL, attr_path,
3990                              NULL, NULL, NULL, o, p);
3991                 return;
3992         }
3993
3994         diff_fill_oid_info(one);
3995         diff_fill_oid_info(two);
3996
3997         if (!pgm &&
3998             DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
3999             (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
4000                 /*
4001                  * a filepair that changes between file and symlink
4002                  * needs to be split into deletion and creation.
4003                  */
4004                 struct diff_filespec *null = alloc_filespec(two->path);
4005                 run_diff_cmd(NULL, name, other, attr_path,
4006                              one, null, &msg, o, p);
4007                 free(null);
4008                 strbuf_release(&msg);
4009
4010                 null = alloc_filespec(one->path);
4011                 run_diff_cmd(NULL, name, other, attr_path,
4012                              null, two, &msg, o, p);
4013                 free(null);
4014         }
4015         else
4016                 run_diff_cmd(pgm, name, other, attr_path,
4017                              one, two, &msg, o, p);
4018
4019         strbuf_release(&msg);
4020 }
4021
4022 static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
4023                          struct diffstat_t *diffstat)
4024 {
4025         const char *name;
4026         const char *other;
4027
4028         if (DIFF_PAIR_UNMERGED(p)) {
4029                 /* unmerged */
4030                 builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, p);
4031                 return;
4032         }
4033
4034         name = p->one->path;
4035         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
4036
4037         if (o->prefix_length)
4038                 strip_prefix(o->prefix_length, &name, &other);
4039
4040         diff_fill_oid_info(p->one);
4041         diff_fill_oid_info(p->two);
4042
4043         builtin_diffstat(name, other, p->one, p->two, diffstat, o, p);
4044 }
4045
4046 static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
4047 {
4048         const char *name;
4049         const char *other;
4050         const char *attr_path;
4051
4052         if (DIFF_PAIR_UNMERGED(p)) {
4053                 /* unmerged */
4054                 return;
4055         }
4056
4057         name = p->one->path;
4058         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
4059         attr_path = other ? other : name;
4060
4061         if (o->prefix_length)
4062                 strip_prefix(o->prefix_length, &name, &other);
4063
4064         diff_fill_oid_info(p->one);
4065         diff_fill_oid_info(p->two);
4066
4067         builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
4068 }
4069
4070 void diff_setup(struct diff_options *options)
4071 {
4072         memcpy(options, &default_diff_options, sizeof(*options));
4073
4074         options->file = stdout;
4075
4076         options->abbrev = DEFAULT_ABBREV;
4077         options->line_termination = '\n';
4078         options->break_opt = -1;
4079         options->rename_limit = -1;
4080         options->dirstat_permille = diff_dirstat_permille_default;
4081         options->context = diff_context_default;
4082         options->interhunkcontext = diff_interhunk_context_default;
4083         options->ws_error_highlight = ws_error_highlight_default;
4084         options->flags.rename_empty = 1;
4085
4086         /* pathchange left =NULL by default */
4087         options->change = diff_change;
4088         options->add_remove = diff_addremove;
4089         options->use_color = diff_use_color_default;
4090         options->detect_rename = diff_detect_rename_default;
4091         options->xdl_opts |= diff_algorithm;
4092         if (diff_indent_heuristic)
4093                 DIFF_XDL_SET(options, INDENT_HEURISTIC);
4094
4095         options->orderfile = diff_order_file_cfg;
4096
4097         if (diff_no_prefix) {
4098                 options->a_prefix = options->b_prefix = "";
4099         } else if (!diff_mnemonic_prefix) {
4100                 options->a_prefix = "a/";
4101                 options->b_prefix = "b/";
4102         }
4103
4104         options->color_moved = diff_color_moved_default;
4105 }
4106
4107 void diff_setup_done(struct diff_options *options)
4108 {
4109         int count = 0;
4110
4111         if (options->set_default)
4112                 options->set_default(options);
4113
4114         if (options->output_format & DIFF_FORMAT_NAME)
4115                 count++;
4116         if (options->output_format & DIFF_FORMAT_NAME_STATUS)
4117                 count++;
4118         if (options->output_format & DIFF_FORMAT_CHECKDIFF)
4119                 count++;
4120         if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
4121                 count++;
4122         if (count > 1)
4123                 die(_("--name-only, --name-status, --check and -s are mutually exclusive"));
4124
4125         /*
4126          * Most of the time we can say "there are changes"
4127          * only by checking if there are changed paths, but
4128          * --ignore-whitespace* options force us to look
4129          * inside contents.
4130          */
4131
4132         if ((options->xdl_opts & XDF_WHITESPACE_FLAGS))
4133                 options->flags.diff_from_contents = 1;
4134         else
4135                 options->flags.diff_from_contents = 0;
4136
4137         if (options->flags.find_copies_harder)
4138                 options->detect_rename = DIFF_DETECT_COPY;
4139
4140         if (!options->flags.relative_name)
4141                 options->prefix = NULL;
4142         if (options->prefix)
4143                 options->prefix_length = strlen(options->prefix);
4144         else
4145                 options->prefix_length = 0;
4146
4147         if (options->output_format & (DIFF_FORMAT_NAME |
4148                                       DIFF_FORMAT_NAME_STATUS |
4149                                       DIFF_FORMAT_CHECKDIFF |
4150                                       DIFF_FORMAT_NO_OUTPUT))
4151                 options->output_format &= ~(DIFF_FORMAT_RAW |
4152                                             DIFF_FORMAT_NUMSTAT |
4153                                             DIFF_FORMAT_DIFFSTAT |
4154                                             DIFF_FORMAT_SHORTSTAT |
4155                                             DIFF_FORMAT_DIRSTAT |
4156                                             DIFF_FORMAT_SUMMARY |
4157                                             DIFF_FORMAT_PATCH);
4158
4159         /*
4160          * These cases always need recursive; we do not drop caller-supplied
4161          * recursive bits for other formats here.
4162          */
4163         if (options->output_format & (DIFF_FORMAT_PATCH |
4164                                       DIFF_FORMAT_NUMSTAT |
4165                                       DIFF_FORMAT_DIFFSTAT |
4166                                       DIFF_FORMAT_SHORTSTAT |
4167                                       DIFF_FORMAT_DIRSTAT |
4168                                       DIFF_FORMAT_SUMMARY |
4169                                       DIFF_FORMAT_CHECKDIFF))
4170                 options->flags.recursive = 1;
4171         /*
4172          * Also pickaxe would not work very well if you do not say recursive
4173          */
4174         if (options->pickaxe)
4175                 options->flags.recursive = 1;
4176         /*
4177          * When patches are generated, submodules diffed against the work tree
4178          * must be checked for dirtiness too so it can be shown in the output
4179          */
4180         if (options->output_format & DIFF_FORMAT_PATCH)
4181                 options->flags.dirty_submodules = 1;
4182
4183         if (options->detect_rename && options->rename_limit < 0)
4184                 options->rename_limit = diff_rename_limit_default;
4185         if (options->setup & DIFF_SETUP_USE_CACHE) {
4186                 if (!active_cache)
4187                         /* read-cache does not die even when it fails
4188                          * so it is safe for us to do this here.  Also
4189                          * it does not smudge active_cache or active_nr
4190                          * when it fails, so we do not have to worry about
4191                          * cleaning it up ourselves either.
4192                          */
4193                         read_cache();
4194         }
4195         if (40 < options->abbrev)
4196                 options->abbrev = 40; /* full */
4197
4198         /*
4199          * It does not make sense to show the first hit we happened
4200          * to have found.  It does not make sense not to return with
4201          * exit code in such a case either.
4202          */
4203         if (options->flags.quick) {
4204                 options->output_format = DIFF_FORMAT_NO_OUTPUT;
4205                 options->flags.exit_with_status = 1;
4206         }
4207
4208         options->diff_path_counter = 0;
4209
4210         if (options->flags.follow_renames && options->pathspec.nr != 1)
4211                 die(_("--follow requires exactly one pathspec"));
4212
4213         if (!options->use_color || external_diff())
4214                 options->color_moved = 0;
4215 }
4216
4217 static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
4218 {
4219         char c, *eq;
4220         int len;
4221
4222         if (*arg != '-')
4223                 return 0;
4224         c = *++arg;
4225         if (!c)
4226                 return 0;
4227         if (c == arg_short) {
4228                 c = *++arg;
4229                 if (!c)
4230                         return 1;
4231                 if (val && isdigit(c)) {
4232                         char *end;
4233                         int n = strtoul(arg, &end, 10);
4234                         if (*end)
4235                                 return 0;
4236                         *val = n;
4237                         return 1;
4238                 }
4239                 return 0;
4240         }
4241         if (c != '-')
4242                 return 0;
4243         arg++;
4244         eq = strchrnul(arg, '=');
4245         len = eq - arg;
4246         if (!len || strncmp(arg, arg_long, len))
4247                 return 0;
4248         if (*eq) {
4249                 int n;
4250                 char *end;
4251                 if (!isdigit(*++eq))
4252                         return 0;
4253                 n = strtoul(eq, &end, 10);
4254                 if (*end)
4255                         return 0;
4256                 *val = n;
4257         }
4258         return 1;
4259 }
4260
4261 static int diff_scoreopt_parse(const char *opt);
4262
4263 static inline int short_opt(char opt, const char **argv,
4264                             const char **optarg)
4265 {
4266         const char *arg = argv[0];
4267         if (arg[0] != '-' || arg[1] != opt)
4268                 return 0;
4269         if (arg[2] != '\0') {
4270                 *optarg = arg + 2;
4271                 return 1;
4272         }
4273         if (!argv[1])
4274                 die("Option '%c' requires a value", opt);
4275         *optarg = argv[1];
4276         return 2;
4277 }
4278
4279 int parse_long_opt(const char *opt, const char **argv,
4280                    const char **optarg)
4281 {
4282         const char *arg = argv[0];
4283         if (!skip_prefix(arg, "--", &arg))
4284                 return 0;
4285         if (!skip_prefix(arg, opt, &arg))
4286                 return 0;
4287         if (*arg == '=') { /* stuck form: --option=value */
4288                 *optarg = arg + 1;
4289                 return 1;
4290         }
4291         if (*arg != '\0')
4292                 return 0;
4293         /* separate form: --option value */
4294         if (!argv[1])
4295                 die("Option '--%s' requires a value", opt);
4296         *optarg = argv[1];
4297         return 2;
4298 }
4299
4300 static int stat_opt(struct diff_options *options, const char **av)
4301 {
4302         const char *arg = av[0];
4303         char *end;
4304         int width = options->stat_width;
4305         int name_width = options->stat_name_width;
4306         int graph_width = options->stat_graph_width;
4307         int count = options->stat_count;
4308         int argcount = 1;
4309
4310         if (!skip_prefix(arg, "--stat", &arg))
4311                 die("BUG: stat option does not begin with --stat: %s", arg);
4312         end = (char *)arg;
4313
4314         switch (*arg) {
4315         case '-':
4316                 if (skip_prefix(arg, "-width", &arg)) {
4317                         if (*arg == '=')
4318                                 width = strtoul(arg + 1, &end, 10);
4319                         else if (!*arg && !av[1])
4320                                 die_want_option("--stat-width");
4321                         else if (!*arg) {
4322                                 width = strtoul(av[1], &end, 10);
4323                                 argcount = 2;
4324                         }
4325                 } else if (skip_prefix(arg, "-name-width", &arg)) {
4326                         if (*arg == '=')
4327                                 name_width = strtoul(arg + 1, &end, 10);
4328                         else if (!*arg && !av[1])
4329                                 die_want_option("--stat-name-width");
4330                         else if (!*arg) {
4331                                 name_width = strtoul(av[1], &end, 10);
4332                                 argcount = 2;
4333                         }
4334                 } else if (skip_prefix(arg, "-graph-width", &arg)) {
4335                         if (*arg == '=')
4336                                 graph_width = strtoul(arg + 1, &end, 10);
4337                         else if (!*arg && !av[1])
4338                                 die_want_option("--stat-graph-width");
4339                         else if (!*arg) {
4340                                 graph_width = strtoul(av[1], &end, 10);
4341                                 argcount = 2;
4342                         }
4343                 } else if (skip_prefix(arg, "-count", &arg)) {
4344                         if (*arg == '=')
4345                                 count = strtoul(arg + 1, &end, 10);
4346                         else if (!*arg && !av[1])
4347                                 die_want_option("--stat-count");
4348                         else if (!*arg) {
4349                                 count = strtoul(av[1], &end, 10);
4350                                 argcount = 2;
4351                         }
4352                 }
4353                 break;
4354         case '=':
4355                 width = strtoul(arg+1, &end, 10);
4356                 if (*end == ',')
4357                         name_width = strtoul(end+1, &end, 10);
4358                 if (*end == ',')
4359                         count = strtoul(end+1, &end, 10);
4360         }
4361
4362         /* Important! This checks all the error cases! */
4363         if (*end)
4364                 return 0;
4365         options->output_format |= DIFF_FORMAT_DIFFSTAT;
4366         options->stat_name_width = name_width;
4367         options->stat_graph_width = graph_width;
4368         options->stat_width = width;
4369         options->stat_count = count;
4370         return argcount;
4371 }
4372
4373 static int parse_dirstat_opt(struct diff_options *options, const char *params)
4374 {
4375         struct strbuf errmsg = STRBUF_INIT;
4376         if (parse_dirstat_params(options, params, &errmsg))
4377                 die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
4378                     errmsg.buf);
4379         strbuf_release(&errmsg);
4380         /*
4381          * The caller knows a dirstat-related option is given from the command
4382          * line; allow it to say "return this_function();"
4383          */
4384         options->output_format |= DIFF_FORMAT_DIRSTAT;
4385         return 1;
4386 }
4387
4388 static int parse_submodule_opt(struct diff_options *options, const char *value)
4389 {
4390         if (parse_submodule_params(options, value))
4391                 die(_("Failed to parse --submodule option parameter: '%s'"),
4392                         value);
4393         return 1;
4394 }
4395
4396 static const char diff_status_letters[] = {
4397         DIFF_STATUS_ADDED,
4398         DIFF_STATUS_COPIED,
4399         DIFF_STATUS_DELETED,
4400         DIFF_STATUS_MODIFIED,
4401         DIFF_STATUS_RENAMED,
4402         DIFF_STATUS_TYPE_CHANGED,
4403         DIFF_STATUS_UNKNOWN,
4404         DIFF_STATUS_UNMERGED,
4405         DIFF_STATUS_FILTER_AON,
4406         DIFF_STATUS_FILTER_BROKEN,
4407         '\0',
4408 };
4409
4410 static unsigned int filter_bit['Z' + 1];
4411
4412 static void prepare_filter_bits(void)
4413 {
4414         int i;
4415
4416         if (!filter_bit[DIFF_STATUS_ADDED]) {
4417                 for (i = 0; diff_status_letters[i]; i++)
4418                         filter_bit[(int) diff_status_letters[i]] = (1 << i);
4419         }
4420 }
4421
4422 static unsigned filter_bit_tst(char status, const struct diff_options *opt)
4423 {
4424         return opt->filter & filter_bit[(int) status];
4425 }
4426
4427 static int parse_diff_filter_opt(const char *optarg, struct diff_options *opt)
4428 {
4429         int i, optch;
4430
4431         prepare_filter_bits();
4432
4433         /*
4434          * If there is a negation e.g. 'd' in the input, and we haven't
4435          * initialized the filter field with another --diff-filter, start
4436          * from full set of bits, except for AON.
4437          */
4438         if (!opt->filter) {
4439                 for (i = 0; (optch = optarg[i]) != '\0'; i++) {
4440                         if (optch < 'a' || 'z' < optch)
4441                                 continue;
4442                         opt->filter = (1 << (ARRAY_SIZE(diff_status_letters) - 1)) - 1;
4443                         opt->filter &= ~filter_bit[DIFF_STATUS_FILTER_AON];
4444                         break;
4445                 }
4446         }
4447
4448         for (i = 0; (optch = optarg[i]) != '\0'; i++) {
4449                 unsigned int bit;
4450                 int negate;
4451
4452                 if ('a' <= optch && optch <= 'z') {
4453                         negate = 1;
4454                         optch = toupper(optch);
4455                 } else {
4456                         negate = 0;
4457                 }
4458
4459                 bit = (0 <= optch && optch <= 'Z') ? filter_bit[optch] : 0;
4460                 if (!bit)
4461                         return optarg[i];
4462                 if (negate)
4463                         opt->filter &= ~bit;
4464                 else
4465                         opt->filter |= bit;
4466         }
4467         return 0;
4468 }
4469
4470 static void enable_patch_output(int *fmt) {
4471         *fmt &= ~DIFF_FORMAT_NO_OUTPUT;
4472         *fmt |= DIFF_FORMAT_PATCH;
4473 }
4474
4475 static int parse_ws_error_highlight_opt(struct diff_options *opt, const char *arg)
4476 {
4477         int val = parse_ws_error_highlight(arg);
4478
4479         if (val < 0) {
4480                 error("unknown value after ws-error-highlight=%.*s",
4481                       -1 - val, arg);
4482                 return 0;
4483         }
4484         opt->ws_error_highlight = val;
4485         return 1;
4486 }
4487
4488 int diff_opt_parse(struct diff_options *options,
4489                    const char **av, int ac, const char *prefix)
4490 {
4491         const char *arg = av[0];
4492         const char *optarg;
4493         int argcount;
4494
4495         if (!prefix)
4496                 prefix = "";
4497
4498         /* Output format options */
4499         if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch")
4500             || opt_arg(arg, 'U', "unified", &options->context))
4501                 enable_patch_output(&options->output_format);
4502         else if (!strcmp(arg, "--raw"))
4503                 options->output_format |= DIFF_FORMAT_RAW;
4504         else if (!strcmp(arg, "--patch-with-raw")) {
4505                 enable_patch_output(&options->output_format);
4506                 options->output_format |= DIFF_FORMAT_RAW;
4507         } else if (!strcmp(arg, "--numstat"))
4508                 options->output_format |= DIFF_FORMAT_NUMSTAT;
4509         else if (!strcmp(arg, "--shortstat"))
4510                 options->output_format |= DIFF_FORMAT_SHORTSTAT;
4511         else if (!strcmp(arg, "-X") || !strcmp(arg, "--dirstat"))
4512                 return parse_dirstat_opt(options, "");
4513         else if (skip_prefix(arg, "-X", &arg))
4514                 return parse_dirstat_opt(options, arg);
4515         else if (skip_prefix(arg, "--dirstat=", &arg))
4516                 return parse_dirstat_opt(options, arg);
4517         else if (!strcmp(arg, "--cumulative"))
4518                 return parse_dirstat_opt(options, "cumulative");
4519         else if (!strcmp(arg, "--dirstat-by-file"))
4520                 return parse_dirstat_opt(options, "files");
4521         else if (skip_prefix(arg, "--dirstat-by-file=", &arg)) {
4522                 parse_dirstat_opt(options, "files");
4523                 return parse_dirstat_opt(options, arg);
4524         }
4525         else if (!strcmp(arg, "--check"))
4526                 options->output_format |= DIFF_FORMAT_CHECKDIFF;
4527         else if (!strcmp(arg, "--summary"))
4528                 options->output_format |= DIFF_FORMAT_SUMMARY;
4529         else if (!strcmp(arg, "--patch-with-stat")) {
4530                 enable_patch_output(&options->output_format);
4531                 options->output_format |= DIFF_FORMAT_DIFFSTAT;
4532         } else if (!strcmp(arg, "--name-only"))
4533                 options->output_format |= DIFF_FORMAT_NAME;
4534         else if (!strcmp(arg, "--name-status"))
4535                 options->output_format |= DIFF_FORMAT_NAME_STATUS;
4536         else if (!strcmp(arg, "-s") || !strcmp(arg, "--no-patch"))
4537                 options->output_format |= DIFF_FORMAT_NO_OUTPUT;
4538         else if (starts_with(arg, "--stat"))
4539                 /* --stat, --stat-width, --stat-name-width, or --stat-count */
4540                 return stat_opt(options, av);
4541
4542         /* renames options */
4543         else if (starts_with(arg, "-B") || starts_with(arg, "--break-rewrites=") ||
4544                  !strcmp(arg, "--break-rewrites")) {
4545                 if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
4546                         return error("invalid argument to -B: %s", arg+2);
4547         }
4548         else if (starts_with(arg, "-M") || starts_with(arg, "--find-renames=") ||
4549                  !strcmp(arg, "--find-renames")) {
4550                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
4551                         return error("invalid argument to -M: %s", arg+2);
4552                 options->detect_rename = DIFF_DETECT_RENAME;
4553         }
4554         else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
4555                 options->irreversible_delete = 1;
4556         }
4557         else if (starts_with(arg, "-C") || starts_with(arg, "--find-copies=") ||
4558                  !strcmp(arg, "--find-copies")) {
4559                 if (options->detect_rename == DIFF_DETECT_COPY)
4560                         options->flags.find_copies_harder = 1;
4561                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
4562                         return error("invalid argument to -C: %s", arg+2);
4563                 options->detect_rename = DIFF_DETECT_COPY;
4564         }
4565         else if (!strcmp(arg, "--no-renames"))
4566                 options->detect_rename = 0;
4567         else if (!strcmp(arg, "--rename-empty"))
4568                 options->flags.rename_empty = 1;
4569         else if (!strcmp(arg, "--no-rename-empty"))
4570                 options->flags.rename_empty = 0;
4571         else if (!strcmp(arg, "--relative"))
4572                 options->flags.relative_name = 1;
4573         else if (skip_prefix(arg, "--relative=", &arg)) {
4574                 options->flags.relative_name = 1;
4575                 options->prefix = arg;
4576         }
4577
4578         /* xdiff options */
4579         else if (!strcmp(arg, "--minimal"))
4580                 DIFF_XDL_SET(options, NEED_MINIMAL);
4581         else if (!strcmp(arg, "--no-minimal"))
4582                 DIFF_XDL_CLR(options, NEED_MINIMAL);
4583         else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
4584                 DIFF_XDL_SET(options, IGNORE_WHITESPACE);
4585         else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
4586                 DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
4587         else if (!strcmp(arg, "--ignore-space-at-eol"))
4588                 DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
4589         else if (!strcmp(arg, "--ignore-cr-at-eol"))
4590                 DIFF_XDL_SET(options, IGNORE_CR_AT_EOL);
4591         else if (!strcmp(arg, "--ignore-blank-lines"))
4592                 DIFF_XDL_SET(options, IGNORE_BLANK_LINES);
4593         else if (!strcmp(arg, "--indent-heuristic"))
4594                 DIFF_XDL_SET(options, INDENT_HEURISTIC);
4595         else if (!strcmp(arg, "--no-indent-heuristic"))
4596                 DIFF_XDL_CLR(options, INDENT_HEURISTIC);
4597         else if (!strcmp(arg, "--patience"))
4598                 options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
4599         else if (!strcmp(arg, "--histogram"))
4600                 options->xdl_opts = DIFF_WITH_ALG(options, HISTOGRAM_DIFF);
4601         else if ((argcount = parse_long_opt("diff-algorithm", av, &optarg))) {
4602                 long value = parse_algorithm_value(optarg);
4603                 if (value < 0)
4604                         return error("option diff-algorithm accepts \"myers\", "
4605                                      "\"minimal\", \"patience\" and \"histogram\"");
4606                 /* clear out previous settings */
4607                 DIFF_XDL_CLR(options, NEED_MINIMAL);
4608                 options->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
4609                 options->xdl_opts |= value;
4610                 return argcount;
4611         }
4612
4613         /* flags options */
4614         else if (!strcmp(arg, "--binary")) {
4615                 enable_patch_output(&options->output_format);
4616                 options->flags.binary = 1;
4617         }
4618         else if (!strcmp(arg, "--full-index"))
4619                 options->flags.full_index = 1;
4620         else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
4621                 options->flags.text = 1;
4622         else if (!strcmp(arg, "-R"))
4623                 options->flags.reverse_diff = 1;
4624         else if (!strcmp(arg, "--find-copies-harder"))
4625                 options->flags.find_copies_harder = 1;
4626         else if (!strcmp(arg, "--follow"))
4627                 options->flags.follow_renames = 1;
4628         else if (!strcmp(arg, "--no-follow")) {
4629                 options->flags.follow_renames = 0;
4630                 options->flags.default_follow_renames = 0;
4631         } else if (!strcmp(arg, "--color"))
4632                 options->use_color = 1;
4633         else if (skip_prefix(arg, "--color=", &arg)) {
4634                 int value = git_config_colorbool(NULL, arg);
4635                 if (value < 0)
4636                         return error("option `color' expects \"always\", \"auto\", or \"never\"");
4637                 options->use_color = value;
4638         }
4639         else if (!strcmp(arg, "--no-color"))
4640                 options->use_color = 0;
4641         else if (!strcmp(arg, "--color-moved")) {
4642                 if (diff_color_moved_default)
4643                         options->color_moved = diff_color_moved_default;
4644                 if (options->color_moved == COLOR_MOVED_NO)
4645                         options->color_moved = COLOR_MOVED_DEFAULT;
4646         } else if (!strcmp(arg, "--no-color-moved"))
4647                 options->color_moved = COLOR_MOVED_NO;
4648         else if (skip_prefix(arg, "--color-moved=", &arg)) {
4649                 int cm = parse_color_moved(arg);
4650                 if (cm < 0)
4651                         die("bad --color-moved argument: %s", arg);
4652                 options->color_moved = cm;
4653         } else if (!strcmp(arg, "--color-words")) {
4654                 options->use_color = 1;
4655                 options->word_diff = DIFF_WORDS_COLOR;
4656         }
4657         else if (skip_prefix(arg, "--color-words=", &arg)) {
4658                 options->use_color = 1;
4659                 options->word_diff = DIFF_WORDS_COLOR;
4660                 options->word_regex = arg;
4661         }
4662         else if (!strcmp(arg, "--word-diff")) {
4663                 if (options->word_diff == DIFF_WORDS_NONE)
4664                         options->word_diff = DIFF_WORDS_PLAIN;
4665         }
4666         else if (skip_prefix(arg, "--word-diff=", &arg)) {
4667                 if (!strcmp(arg, "plain"))
4668                         options->word_diff = DIFF_WORDS_PLAIN;
4669                 else if (!strcmp(arg, "color")) {
4670                         options->use_color = 1;
4671                         options->word_diff = DIFF_WORDS_COLOR;
4672                 }
4673                 else if (!strcmp(arg, "porcelain"))
4674                         options->word_diff = DIFF_WORDS_PORCELAIN;
4675                 else if (!strcmp(arg, "none"))
4676                         options->word_diff = DIFF_WORDS_NONE;
4677                 else
4678                         die("bad --word-diff argument: %s", arg);
4679         }
4680         else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
4681                 if (options->word_diff == DIFF_WORDS_NONE)
4682                         options->word_diff = DIFF_WORDS_PLAIN;
4683                 options->word_regex = optarg;
4684                 return argcount;
4685         }
4686         else if (!strcmp(arg, "--exit-code"))
4687                 options->flags.exit_with_status = 1;
4688         else if (!strcmp(arg, "--quiet"))
4689                 options->flags.quick = 1;
4690         else if (!strcmp(arg, "--ext-diff"))
4691                 options->flags.allow_external = 1;
4692         else if (!strcmp(arg, "--no-ext-diff"))
4693                 options->flags.allow_external = 0;
4694         else if (!strcmp(arg, "--textconv")) {
4695                 options->flags.allow_textconv = 1;
4696                 options->flags.textconv_set_via_cmdline = 1;
4697         } else if (!strcmp(arg, "--no-textconv"))
4698                 options->flags.allow_textconv = 0;
4699         else if (!strcmp(arg, "--ignore-submodules")) {
4700                 options->flags.override_submodule_config = 1;
4701                 handle_ignore_submodules_arg(options, "all");
4702         } else if (skip_prefix(arg, "--ignore-submodules=", &arg)) {
4703                 options->flags.override_submodule_config = 1;
4704                 handle_ignore_submodules_arg(options, arg);
4705         } else if (!strcmp(arg, "--submodule"))
4706                 options->submodule_format = DIFF_SUBMODULE_LOG;
4707         else if (skip_prefix(arg, "--submodule=", &arg))
4708                 return parse_submodule_opt(options, arg);
4709         else if (skip_prefix(arg, "--ws-error-highlight=", &arg))
4710                 return parse_ws_error_highlight_opt(options, arg);
4711         else if (!strcmp(arg, "--ita-invisible-in-index"))
4712                 options->ita_invisible_in_index = 1;
4713         else if (!strcmp(arg, "--ita-visible-in-index"))
4714                 options->ita_invisible_in_index = 0;
4715
4716         /* misc options */
4717         else if (!strcmp(arg, "-z"))
4718                 options->line_termination = 0;
4719         else if ((argcount = short_opt('l', av, &optarg))) {
4720                 options->rename_limit = strtoul(optarg, NULL, 10);
4721                 return argcount;
4722         }
4723         else if ((argcount = short_opt('S', av, &optarg))) {
4724                 options->pickaxe = optarg;
4725                 options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
4726                 return argcount;
4727         } else if ((argcount = short_opt('G', av, &optarg))) {
4728                 options->pickaxe = optarg;
4729                 options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
4730                 return argcount;
4731         }
4732         else if (!strcmp(arg, "--pickaxe-all"))
4733                 options->pickaxe_opts |= DIFF_PICKAXE_ALL;
4734         else if (!strcmp(arg, "--pickaxe-regex"))
4735                 options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
4736         else if ((argcount = short_opt('O', av, &optarg))) {
4737                 options->orderfile = prefix_filename(prefix, optarg);
4738                 return argcount;
4739         }
4740         else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
4741                 int offending = parse_diff_filter_opt(optarg, options);
4742                 if (offending)
4743                         die("unknown change class '%c' in --diff-filter=%s",
4744                             offending, optarg);
4745                 return argcount;
4746         }
4747         else if (!strcmp(arg, "--no-abbrev"))
4748                 options->abbrev = 0;
4749         else if (!strcmp(arg, "--abbrev"))
4750                 options->abbrev = DEFAULT_ABBREV;
4751         else if (skip_prefix(arg, "--abbrev=", &arg)) {
4752                 options->abbrev = strtoul(arg, NULL, 10);
4753                 if (options->abbrev < MINIMUM_ABBREV)
4754                         options->abbrev = MINIMUM_ABBREV;
4755                 else if (40 < options->abbrev)
4756                         options->abbrev = 40;
4757         }
4758         else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
4759                 options->a_prefix = optarg;
4760                 return argcount;
4761         }
4762         else if ((argcount = parse_long_opt("line-prefix", av, &optarg))) {
4763                 options->line_prefix = optarg;
4764                 options->line_prefix_length = strlen(options->line_prefix);
4765                 graph_setup_line_prefix(options);
4766                 return argcount;
4767         }
4768         else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
4769                 options->b_prefix = optarg;
4770                 return argcount;
4771         }
4772         else if (!strcmp(arg, "--no-prefix"))
4773                 options->a_prefix = options->b_prefix = "";
4774         else if (opt_arg(arg, '\0', "inter-hunk-context",
4775                          &options->interhunkcontext))
4776                 ;
4777         else if (!strcmp(arg, "-W"))
4778                 options->flags.funccontext = 1;
4779         else if (!strcmp(arg, "--function-context"))
4780                 options->flags.funccontext = 1;
4781         else if (!strcmp(arg, "--no-function-context"))
4782                 options->flags.funccontext = 0;
4783         else if ((argcount = parse_long_opt("output", av, &optarg))) {
4784                 char *path = prefix_filename(prefix, optarg);
4785                 options->file = xfopen(path, "w");
4786                 options->close_file = 1;
4787                 if (options->use_color != GIT_COLOR_ALWAYS)
4788                         options->use_color = GIT_COLOR_NEVER;
4789                 free(path);
4790                 return argcount;
4791         } else
4792                 return 0;
4793         return 1;
4794 }
4795
4796 int parse_rename_score(const char **cp_p)
4797 {
4798         unsigned long num, scale;
4799         int ch, dot;
4800         const char *cp = *cp_p;
4801
4802         num = 0;
4803         scale = 1;
4804         dot = 0;
4805         for (;;) {
4806                 ch = *cp;
4807                 if ( !dot && ch == '.' ) {
4808                         scale = 1;
4809                         dot = 1;
4810                 } else if ( ch == '%' ) {
4811                         scale = dot ? scale*100 : 100;
4812                         cp++;   /* % is always at the end */
4813                         break;
4814                 } else if ( ch >= '0' && ch <= '9' ) {
4815                         if ( scale < 100000 ) {
4816                                 scale *= 10;
4817                                 num = (num*10) + (ch-'0');
4818                         }
4819                 } else {
4820                         break;
4821                 }
4822                 cp++;
4823         }
4824         *cp_p = cp;
4825
4826         /* user says num divided by scale and we say internally that
4827          * is MAX_SCORE * num / scale.
4828          */
4829         return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
4830 }
4831
4832 static int diff_scoreopt_parse(const char *opt)
4833 {
4834         int opt1, opt2, cmd;
4835
4836         if (*opt++ != '-')
4837                 return -1;
4838         cmd = *opt++;
4839         if (cmd == '-') {
4840                 /* convert the long-form arguments into short-form versions */
4841                 if (skip_prefix(opt, "break-rewrites", &opt)) {
4842                         if (*opt == 0 || *opt++ == '=')
4843                                 cmd = 'B';
4844                 } else if (skip_prefix(opt, "find-copies", &opt)) {
4845                         if (*opt == 0 || *opt++ == '=')
4846                                 cmd = 'C';
4847                 } else if (skip_prefix(opt, "find-renames", &opt)) {
4848                         if (*opt == 0 || *opt++ == '=')
4849                                 cmd = 'M';
4850                 }
4851         }
4852         if (cmd != 'M' && cmd != 'C' && cmd != 'B')
4853                 return -1; /* that is not a -M, -C, or -B option */
4854
4855         opt1 = parse_rename_score(&opt);
4856         if (cmd != 'B')
4857                 opt2 = 0;
4858         else {
4859                 if (*opt == 0)
4860                         opt2 = 0;
4861                 else if (*opt != '/')
4862                         return -1; /* we expect -B80/99 or -B80 */
4863                 else {
4864                         opt++;
4865                         opt2 = parse_rename_score(&opt);
4866                 }
4867         }
4868         if (*opt != 0)
4869                 return -1;
4870         return opt1 | (opt2 << 16);
4871 }
4872
4873 struct diff_queue_struct diff_queued_diff;
4874
4875 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
4876 {
4877         ALLOC_GROW(queue->queue, queue->nr + 1, queue->alloc);
4878         queue->queue[queue->nr++] = dp;
4879 }
4880
4881 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
4882                                  struct diff_filespec *one,
4883                                  struct diff_filespec *two)
4884 {
4885         struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
4886         dp->one = one;
4887         dp->two = two;
4888         if (queue)
4889                 diff_q(queue, dp);
4890         return dp;
4891 }
4892
4893 void diff_free_filepair(struct diff_filepair *p)
4894 {
4895         free_filespec(p->one);
4896         free_filespec(p->two);
4897         free(p);
4898 }
4899
4900 const char *diff_aligned_abbrev(const struct object_id *oid, int len)
4901 {
4902         int abblen;
4903         const char *abbrev;
4904
4905         if (len == GIT_SHA1_HEXSZ)
4906                 return oid_to_hex(oid);
4907
4908         abbrev = diff_abbrev_oid(oid, len);
4909         abblen = strlen(abbrev);
4910
4911         /*
4912          * In well-behaved cases, where the abbbreviated result is the
4913          * same as the requested length, append three dots after the
4914          * abbreviation (hence the whole logic is limited to the case
4915          * where abblen < 37); when the actual abbreviated result is a
4916          * bit longer than the requested length, we reduce the number
4917          * of dots so that they match the well-behaved ones.  However,
4918          * if the actual abbreviation is longer than the requested
4919          * length by more than three, we give up on aligning, and add
4920          * three dots anyway, to indicate that the output is not the
4921          * full object name.  Yes, this may be suboptimal, but this
4922          * appears only in "diff --raw --abbrev" output and it is not
4923          * worth the effort to change it now.  Note that this would
4924          * likely to work fine when the automatic sizing of default
4925          * abbreviation length is used--we would be fed -1 in "len" in
4926          * that case, and will end up always appending three-dots, but
4927          * the automatic sizing is supposed to give abblen that ensures
4928          * uniqueness across all objects (statistically speaking).
4929          */
4930         if (abblen < GIT_SHA1_HEXSZ - 3) {
4931                 static char hex[GIT_MAX_HEXSZ + 1];
4932                 if (len < abblen && abblen <= len + 2)
4933                         xsnprintf(hex, sizeof(hex), "%s%.*s", abbrev, len+3-abblen, "..");
4934                 else
4935                         xsnprintf(hex, sizeof(hex), "%s...", abbrev);
4936                 return hex;
4937         }
4938
4939         return oid_to_hex(oid);
4940 }
4941
4942 static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
4943 {
4944         int line_termination = opt->line_termination;
4945         int inter_name_termination = line_termination ? '\t' : '\0';
4946
4947         fprintf(opt->file, "%s", diff_line_prefix(opt));
4948         if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
4949                 fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
4950                         diff_aligned_abbrev(&p->one->oid, opt->abbrev));
4951                 fprintf(opt->file, "%s ",
4952                         diff_aligned_abbrev(&p->two->oid, opt->abbrev));
4953         }
4954         if (p->score) {
4955                 fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
4956                         inter_name_termination);
4957         } else {
4958                 fprintf(opt->file, "%c%c", p->status, inter_name_termination);
4959         }
4960
4961         if (p->status == DIFF_STATUS_COPIED ||
4962             p->status == DIFF_STATUS_RENAMED) {
4963                 const char *name_a, *name_b;
4964                 name_a = p->one->path;
4965                 name_b = p->two->path;
4966                 strip_prefix(opt->prefix_length, &name_a, &name_b);
4967                 write_name_quoted(name_a, opt->file, inter_name_termination);
4968                 write_name_quoted(name_b, opt->file, line_termination);
4969         } else {
4970                 const char *name_a, *name_b;
4971                 name_a = p->one->mode ? p->one->path : p->two->path;
4972                 name_b = NULL;
4973                 strip_prefix(opt->prefix_length, &name_a, &name_b);
4974                 write_name_quoted(name_a, opt->file, line_termination);
4975         }
4976 }
4977
4978 int diff_unmodified_pair(struct diff_filepair *p)
4979 {
4980         /* This function is written stricter than necessary to support
4981          * the currently implemented transformers, but the idea is to
4982          * let transformers to produce diff_filepairs any way they want,
4983          * and filter and clean them up here before producing the output.
4984          */
4985         struct diff_filespec *one = p->one, *two = p->two;
4986
4987         if (DIFF_PAIR_UNMERGED(p))
4988                 return 0; /* unmerged is interesting */
4989
4990         /* deletion, addition, mode or type change
4991          * and rename are all interesting.
4992          */
4993         if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
4994             DIFF_PAIR_MODE_CHANGED(p) ||
4995             strcmp(one->path, two->path))
4996                 return 0;
4997
4998         /* both are valid and point at the same path.  that is, we are
4999          * dealing with a change.
5000          */
5001         if (one->oid_valid && two->oid_valid &&
5002             !oidcmp(&one->oid, &two->oid) &&
5003             !one->dirty_submodule && !two->dirty_submodule)
5004                 return 1; /* no change */
5005         if (!one->oid_valid && !two->oid_valid)
5006                 return 1; /* both look at the same file on the filesystem. */
5007         return 0;
5008 }
5009
5010 static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
5011 {
5012         if (diff_unmodified_pair(p))
5013                 return;
5014
5015         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5016             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5017                 return; /* no tree diffs in patch format */
5018
5019         run_diff(p, o);
5020 }
5021
5022 static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
5023                             struct diffstat_t *diffstat)
5024 {
5025         if (diff_unmodified_pair(p))
5026                 return;
5027
5028         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5029             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5030                 return; /* no useful stat for tree diffs */
5031
5032         run_diffstat(p, o, diffstat);
5033 }
5034
5035 static void diff_flush_checkdiff(struct diff_filepair *p,
5036                 struct diff_options *o)
5037 {
5038         if (diff_unmodified_pair(p))
5039                 return;
5040
5041         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5042             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5043                 return; /* nothing to check in tree diffs */
5044
5045         run_checkdiff(p, o);
5046 }
5047
5048 int diff_queue_is_empty(void)
5049 {
5050         struct diff_queue_struct *q = &diff_queued_diff;
5051         int i;
5052         for (i = 0; i < q->nr; i++)
5053                 if (!diff_unmodified_pair(q->queue[i]))
5054                         return 0;
5055         return 1;
5056 }
5057
5058 #if DIFF_DEBUG
5059 void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
5060 {
5061         fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
5062                 x, one ? one : "",
5063                 s->path,
5064                 DIFF_FILE_VALID(s) ? "valid" : "invalid",
5065                 s->mode,
5066                 s->oid_valid ? oid_to_hex(&s->oid) : "");
5067         fprintf(stderr, "queue[%d] %s size %lu\n",
5068                 x, one ? one : "",
5069                 s->size);
5070 }
5071
5072 void diff_debug_filepair(const struct diff_filepair *p, int i)
5073 {
5074         diff_debug_filespec(p->one, i, "one");
5075         diff_debug_filespec(p->two, i, "two");
5076         fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
5077                 p->score, p->status ? p->status : '?',
5078                 p->one->rename_used, p->broken_pair);
5079 }
5080
5081 void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
5082 {
5083         int i;
5084         if (msg)
5085                 fprintf(stderr, "%s\n", msg);
5086         fprintf(stderr, "q->nr = %d\n", q->nr);
5087         for (i = 0; i < q->nr; i++) {
5088                 struct diff_filepair *p = q->queue[i];
5089                 diff_debug_filepair(p, i);
5090         }
5091 }
5092 #endif
5093
5094 static void diff_resolve_rename_copy(void)
5095 {
5096         int i;
5097         struct diff_filepair *p;
5098         struct diff_queue_struct *q = &diff_queued_diff;
5099
5100         diff_debug_queue("resolve-rename-copy", q);
5101
5102         for (i = 0; i < q->nr; i++) {
5103                 p = q->queue[i];
5104                 p->status = 0; /* undecided */
5105                 if (DIFF_PAIR_UNMERGED(p))
5106                         p->status = DIFF_STATUS_UNMERGED;
5107                 else if (!DIFF_FILE_VALID(p->one))
5108                         p->status = DIFF_STATUS_ADDED;
5109                 else if (!DIFF_FILE_VALID(p->two))
5110                         p->status = DIFF_STATUS_DELETED;
5111                 else if (DIFF_PAIR_TYPE_CHANGED(p))
5112                         p->status = DIFF_STATUS_TYPE_CHANGED;
5113
5114                 /* from this point on, we are dealing with a pair
5115                  * whose both sides are valid and of the same type, i.e.
5116                  * either in-place edit or rename/copy edit.
5117                  */
5118                 else if (DIFF_PAIR_RENAME(p)) {
5119                         /*
5120                          * A rename might have re-connected a broken
5121                          * pair up, causing the pathnames to be the
5122                          * same again. If so, that's not a rename at
5123                          * all, just a modification..
5124                          *
5125                          * Otherwise, see if this source was used for
5126                          * multiple renames, in which case we decrement
5127                          * the count, and call it a copy.
5128                          */
5129                         if (!strcmp(p->one->path, p->two->path))
5130                                 p->status = DIFF_STATUS_MODIFIED;
5131                         else if (--p->one->rename_used > 0)
5132                                 p->status = DIFF_STATUS_COPIED;
5133                         else
5134                                 p->status = DIFF_STATUS_RENAMED;
5135                 }
5136                 else if (oidcmp(&p->one->oid, &p->two->oid) ||
5137                          p->one->mode != p->two->mode ||
5138                          p->one->dirty_submodule ||
5139                          p->two->dirty_submodule ||
5140                          is_null_oid(&p->one->oid))
5141                         p->status = DIFF_STATUS_MODIFIED;
5142                 else {
5143                         /* This is a "no-change" entry and should not
5144                          * happen anymore, but prepare for broken callers.
5145                          */
5146                         error("feeding unmodified %s to diffcore",
5147                               p->one->path);
5148                         p->status = DIFF_STATUS_UNKNOWN;
5149                 }
5150         }
5151         diff_debug_queue("resolve-rename-copy done", q);
5152 }
5153
5154 static int check_pair_status(struct diff_filepair *p)
5155 {
5156         switch (p->status) {
5157         case DIFF_STATUS_UNKNOWN:
5158                 return 0;
5159         case 0:
5160                 die("internal error in diff-resolve-rename-copy");
5161         default:
5162                 return 1;
5163         }
5164 }
5165
5166 static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
5167 {
5168         int fmt = opt->output_format;
5169
5170         if (fmt & DIFF_FORMAT_CHECKDIFF)
5171                 diff_flush_checkdiff(p, opt);
5172         else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
5173                 diff_flush_raw(p, opt);
5174         else if (fmt & DIFF_FORMAT_NAME) {
5175                 const char *name_a, *name_b;
5176                 name_a = p->two->path;
5177                 name_b = NULL;
5178                 strip_prefix(opt->prefix_length, &name_a, &name_b);
5179                 fprintf(opt->file, "%s", diff_line_prefix(opt));
5180                 write_name_quoted(name_a, opt->file, opt->line_termination);
5181         }
5182 }
5183
5184 static void show_file_mode_name(struct diff_options *opt, const char *newdelete, struct diff_filespec *fs)
5185 {
5186         struct strbuf sb = STRBUF_INIT;
5187         if (fs->mode)
5188                 strbuf_addf(&sb, " %s mode %06o ", newdelete, fs->mode);
5189         else
5190                 strbuf_addf(&sb, " %s ", newdelete);
5191
5192         quote_c_style(fs->path, &sb, NULL, 0);
5193         strbuf_addch(&sb, '\n');
5194         emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5195                          sb.buf, sb.len, 0);
5196         strbuf_release(&sb);
5197 }
5198
5199 static void show_mode_change(struct diff_options *opt, struct diff_filepair *p,
5200                 int show_name)
5201 {
5202         if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
5203                 struct strbuf sb = STRBUF_INIT;
5204                 strbuf_addf(&sb, " mode change %06o => %06o",
5205                             p->one->mode, p->two->mode);
5206                 if (show_name) {
5207                         strbuf_addch(&sb, ' ');
5208                         quote_c_style(p->two->path, &sb, NULL, 0);
5209                 }
5210                 strbuf_addch(&sb, '\n');
5211                 emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5212                                  sb.buf, sb.len, 0);
5213                 strbuf_release(&sb);
5214         }
5215 }
5216
5217 static void show_rename_copy(struct diff_options *opt, const char *renamecopy,
5218                 struct diff_filepair *p)
5219 {
5220         struct strbuf sb = STRBUF_INIT;
5221         char *names = pprint_rename(p->one->path, p->two->path);
5222         strbuf_addf(&sb, " %s %s (%d%%)\n",
5223                         renamecopy, names, similarity_index(p));
5224         free(names);
5225         emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5226                                  sb.buf, sb.len, 0);
5227         show_mode_change(opt, p, 0);
5228         strbuf_release(&sb);
5229 }
5230
5231 static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
5232 {
5233         switch(p->status) {
5234         case DIFF_STATUS_DELETED:
5235                 show_file_mode_name(opt, "delete", p->one);
5236                 break;
5237         case DIFF_STATUS_ADDED:
5238                 show_file_mode_name(opt, "create", p->two);
5239                 break;
5240         case DIFF_STATUS_COPIED:
5241                 show_rename_copy(opt, "copy", p);
5242                 break;
5243         case DIFF_STATUS_RENAMED:
5244                 show_rename_copy(opt, "rename", p);
5245                 break;
5246         default:
5247                 if (p->score) {
5248                         struct strbuf sb = STRBUF_INIT;
5249                         strbuf_addstr(&sb, " rewrite ");
5250                         quote_c_style(p->two->path, &sb, NULL, 0);
5251                         strbuf_addf(&sb, " (%d%%)\n", similarity_index(p));
5252                         emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5253                                          sb.buf, sb.len, 0);
5254                         strbuf_release(&sb);
5255                 }
5256                 show_mode_change(opt, p, !p->score);
5257                 break;
5258         }
5259 }
5260
5261 struct patch_id_t {
5262         git_SHA_CTX *ctx;
5263         int patchlen;
5264 };
5265
5266 static int remove_space(char *line, int len)
5267 {
5268         int i;
5269         char *dst = line;
5270         unsigned char c;
5271
5272         for (i = 0; i < len; i++)
5273                 if (!isspace((c = line[i])))
5274                         *dst++ = c;
5275
5276         return dst - line;
5277 }
5278
5279 static void patch_id_consume(void *priv, char *line, unsigned long len)
5280 {
5281         struct patch_id_t *data = priv;
5282         int new_len;
5283
5284         /* Ignore line numbers when computing the SHA1 of the patch */
5285         if (starts_with(line, "@@ -"))
5286                 return;
5287
5288         new_len = remove_space(line, len);
5289
5290         git_SHA1_Update(data->ctx, line, new_len);
5291         data->patchlen += new_len;
5292 }
5293
5294 static void patch_id_add_string(git_SHA_CTX *ctx, const char *str)
5295 {
5296         git_SHA1_Update(ctx, str, strlen(str));
5297 }
5298
5299 static void patch_id_add_mode(git_SHA_CTX *ctx, unsigned mode)
5300 {
5301         /* large enough for 2^32 in octal */
5302         char buf[12];
5303         int len = xsnprintf(buf, sizeof(buf), "%06o", mode);
5304         git_SHA1_Update(ctx, buf, len);
5305 }
5306
5307 /* returns 0 upon success, and writes result into sha1 */
5308 static int diff_get_patch_id(struct diff_options *options, struct object_id *oid, int diff_header_only)
5309 {
5310         struct diff_queue_struct *q = &diff_queued_diff;
5311         int i;
5312         git_SHA_CTX ctx;
5313         struct patch_id_t data;
5314
5315         git_SHA1_Init(&ctx);
5316         memset(&data, 0, sizeof(struct patch_id_t));
5317         data.ctx = &ctx;
5318
5319         for (i = 0; i < q->nr; i++) {
5320                 xpparam_t xpp;
5321                 xdemitconf_t xecfg;
5322                 mmfile_t mf1, mf2;
5323                 struct diff_filepair *p = q->queue[i];
5324                 int len1, len2;
5325
5326                 memset(&xpp, 0, sizeof(xpp));
5327                 memset(&xecfg, 0, sizeof(xecfg));
5328                 if (p->status == 0)
5329                         return error("internal diff status error");
5330                 if (p->status == DIFF_STATUS_UNKNOWN)
5331                         continue;
5332                 if (diff_unmodified_pair(p))
5333                         continue;
5334                 if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5335                     (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5336                         continue;
5337                 if (DIFF_PAIR_UNMERGED(p))
5338                         continue;
5339
5340                 diff_fill_oid_info(p->one);
5341                 diff_fill_oid_info(p->two);
5342
5343                 len1 = remove_space(p->one->path, strlen(p->one->path));
5344                 len2 = remove_space(p->two->path, strlen(p->two->path));
5345                 patch_id_add_string(&ctx, "diff--git");
5346                 patch_id_add_string(&ctx, "a/");
5347                 git_SHA1_Update(&ctx, p->one->path, len1);
5348                 patch_id_add_string(&ctx, "b/");
5349                 git_SHA1_Update(&ctx, p->two->path, len2);
5350
5351                 if (p->one->mode == 0) {
5352                         patch_id_add_string(&ctx, "newfilemode");
5353                         patch_id_add_mode(&ctx, p->two->mode);
5354                         patch_id_add_string(&ctx, "---/dev/null");
5355                         patch_id_add_string(&ctx, "+++b/");
5356                         git_SHA1_Update(&ctx, p->two->path, len2);
5357                 } else if (p->two->mode == 0) {
5358                         patch_id_add_string(&ctx, "deletedfilemode");
5359                         patch_id_add_mode(&ctx, p->one->mode);
5360                         patch_id_add_string(&ctx, "---a/");
5361                         git_SHA1_Update(&ctx, p->one->path, len1);
5362                         patch_id_add_string(&ctx, "+++/dev/null");
5363                 } else {
5364                         patch_id_add_string(&ctx, "---a/");
5365                         git_SHA1_Update(&ctx, p->one->path, len1);
5366                         patch_id_add_string(&ctx, "+++b/");
5367                         git_SHA1_Update(&ctx, p->two->path, len2);
5368                 }
5369
5370                 if (diff_header_only)
5371                         continue;
5372
5373                 if (fill_mmfile(&mf1, p->one) < 0 ||
5374                     fill_mmfile(&mf2, p->two) < 0)
5375                         return error("unable to read files to diff");
5376
5377                 if (diff_filespec_is_binary(p->one) ||
5378                     diff_filespec_is_binary(p->two)) {
5379                         git_SHA1_Update(&ctx, oid_to_hex(&p->one->oid),
5380                                         GIT_SHA1_HEXSZ);
5381                         git_SHA1_Update(&ctx, oid_to_hex(&p->two->oid),
5382                                         GIT_SHA1_HEXSZ);
5383                         continue;
5384                 }
5385
5386                 xpp.flags = 0;
5387                 xecfg.ctxlen = 3;
5388                 xecfg.flags = 0;
5389                 if (xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
5390                                   &xpp, &xecfg))
5391                         return error("unable to generate patch-id diff for %s",
5392                                      p->one->path);
5393         }
5394
5395         git_SHA1_Final(oid->hash, &ctx);
5396         return 0;
5397 }
5398
5399 int diff_flush_patch_id(struct diff_options *options, struct object_id *oid, int diff_header_only)
5400 {
5401         struct diff_queue_struct *q = &diff_queued_diff;
5402         int i;
5403         int result = diff_get_patch_id(options, oid, diff_header_only);
5404
5405         for (i = 0; i < q->nr; i++)
5406                 diff_free_filepair(q->queue[i]);
5407
5408         free(q->queue);
5409         DIFF_QUEUE_CLEAR(q);
5410
5411         return result;
5412 }
5413
5414 static int is_summary_empty(const struct diff_queue_struct *q)
5415 {
5416         int i;
5417
5418         for (i = 0; i < q->nr; i++) {
5419                 const struct diff_filepair *p = q->queue[i];
5420
5421                 switch (p->status) {
5422                 case DIFF_STATUS_DELETED:
5423                 case DIFF_STATUS_ADDED:
5424                 case DIFF_STATUS_COPIED:
5425                 case DIFF_STATUS_RENAMED:
5426                         return 0;
5427                 default:
5428                         if (p->score)
5429                                 return 0;
5430                         if (p->one->mode && p->two->mode &&
5431                             p->one->mode != p->two->mode)
5432                                 return 0;
5433                         break;
5434                 }
5435         }
5436         return 1;
5437 }
5438
5439 static const char rename_limit_warning[] =
5440 N_("inexact rename detection was skipped due to too many files.");
5441
5442 static const char degrade_cc_to_c_warning[] =
5443 N_("only found copies from modified paths due to too many files.");
5444
5445 static const char rename_limit_advice[] =
5446 N_("you may want to set your %s variable to at least "
5447    "%d and retry the command.");
5448
5449 void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
5450 {
5451         if (degraded_cc)
5452                 warning(_(degrade_cc_to_c_warning));
5453         else if (needed)
5454                 warning(_(rename_limit_warning));
5455         else
5456                 return;
5457         if (0 < needed && needed < 32767)
5458                 warning(_(rename_limit_advice), varname, needed);
5459 }
5460
5461 static void diff_flush_patch_all_file_pairs(struct diff_options *o)
5462 {
5463         int i;
5464         static struct emitted_diff_symbols esm = EMITTED_DIFF_SYMBOLS_INIT;
5465         struct diff_queue_struct *q = &diff_queued_diff;
5466
5467         if (WSEH_NEW & WS_RULE_MASK)
5468                 die("BUG: WS rules bit mask overlaps with diff symbol flags");
5469
5470         if (o->color_moved)
5471                 o->emitted_symbols = &esm;
5472
5473         for (i = 0; i < q->nr; i++) {
5474                 struct diff_filepair *p = q->queue[i];
5475                 if (check_pair_status(p))
5476                         diff_flush_patch(p, o);
5477         }
5478
5479         if (o->emitted_symbols) {
5480                 if (o->color_moved) {
5481                         struct hashmap add_lines, del_lines;
5482
5483                         hashmap_init(&del_lines,
5484                                      (hashmap_cmp_fn)moved_entry_cmp, o, 0);
5485                         hashmap_init(&add_lines,
5486                                      (hashmap_cmp_fn)moved_entry_cmp, o, 0);
5487
5488                         add_lines_to_move_detection(o, &add_lines, &del_lines);
5489                         mark_color_as_moved(o, &add_lines, &del_lines);
5490                         if (o->color_moved == COLOR_MOVED_ZEBRA_DIM)
5491                                 dim_moved_lines(o);
5492
5493                         hashmap_free(&add_lines, 0);
5494                         hashmap_free(&del_lines, 0);
5495                 }
5496
5497                 for (i = 0; i < esm.nr; i++)
5498                         emit_diff_symbol_from_struct(o, &esm.buf[i]);
5499
5500                 for (i = 0; i < esm.nr; i++)
5501                         free((void *)esm.buf[i].line);
5502         }
5503         esm.nr = 0;
5504 }
5505
5506 void diff_flush(struct diff_options *options)
5507 {
5508         struct diff_queue_struct *q = &diff_queued_diff;
5509         int i, output_format = options->output_format;
5510         int separator = 0;
5511         int dirstat_by_line = 0;
5512
5513         /*
5514          * Order: raw, stat, summary, patch
5515          * or:    name/name-status/checkdiff (other bits clear)
5516          */
5517         if (!q->nr)
5518                 goto free_queue;
5519
5520         if (output_format & (DIFF_FORMAT_RAW |
5521                              DIFF_FORMAT_NAME |
5522                              DIFF_FORMAT_NAME_STATUS |
5523                              DIFF_FORMAT_CHECKDIFF)) {
5524                 for (i = 0; i < q->nr; i++) {
5525                         struct diff_filepair *p = q->queue[i];
5526                         if (check_pair_status(p))
5527                                 flush_one_pair(p, options);
5528                 }
5529                 separator++;
5530         }
5531
5532         if (output_format & DIFF_FORMAT_DIRSTAT && options->flags.dirstat_by_line)
5533                 dirstat_by_line = 1;
5534
5535         if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
5536             dirstat_by_line) {
5537                 struct diffstat_t diffstat;
5538
5539                 memset(&diffstat, 0, sizeof(struct diffstat_t));
5540                 for (i = 0; i < q->nr; i++) {
5541                         struct diff_filepair *p = q->queue[i];
5542                         if (check_pair_status(p))
5543                                 diff_flush_stat(p, options, &diffstat);
5544                 }
5545                 if (output_format & DIFF_FORMAT_NUMSTAT)
5546                         show_numstat(&diffstat, options);
5547                 if (output_format & DIFF_FORMAT_DIFFSTAT)
5548                         show_stats(&diffstat, options);
5549                 if (output_format & DIFF_FORMAT_SHORTSTAT)
5550                         show_shortstats(&diffstat, options);
5551                 if (output_format & DIFF_FORMAT_DIRSTAT && dirstat_by_line)
5552                         show_dirstat_by_line(&diffstat, options);
5553                 free_diffstat_info(&diffstat);
5554                 separator++;
5555         }
5556         if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
5557                 show_dirstat(options);
5558
5559         if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
5560                 for (i = 0; i < q->nr; i++) {
5561                         diff_summary(options, q->queue[i]);
5562                 }
5563                 separator++;
5564         }
5565
5566         if (output_format & DIFF_FORMAT_NO_OUTPUT &&
5567             options->flags.exit_with_status &&
5568             options->flags.diff_from_contents) {
5569                 /*
5570                  * run diff_flush_patch for the exit status. setting
5571                  * options->file to /dev/null should be safe, because we
5572                  * aren't supposed to produce any output anyway.
5573                  */
5574                 if (options->close_file)
5575                         fclose(options->file);
5576                 options->file = xfopen("/dev/null", "w");
5577                 options->close_file = 1;
5578                 options->color_moved = 0;
5579                 for (i = 0; i < q->nr; i++) {
5580                         struct diff_filepair *p = q->queue[i];
5581                         if (check_pair_status(p))
5582                                 diff_flush_patch(p, options);
5583                         if (options->found_changes)
5584                                 break;
5585                 }
5586         }
5587
5588         if (output_format & DIFF_FORMAT_PATCH) {
5589                 if (separator) {
5590                         emit_diff_symbol(options, DIFF_SYMBOL_SEPARATOR, NULL, 0, 0);
5591                         if (options->stat_sep)
5592                                 /* attach patch instead of inline */
5593                                 emit_diff_symbol(options, DIFF_SYMBOL_STAT_SEP,
5594                                                  NULL, 0, 0);
5595                 }
5596
5597                 diff_flush_patch_all_file_pairs(options);
5598         }
5599
5600         if (output_format & DIFF_FORMAT_CALLBACK)
5601                 options->format_callback(q, options, options->format_callback_data);
5602
5603         for (i = 0; i < q->nr; i++)
5604                 diff_free_filepair(q->queue[i]);
5605 free_queue:
5606         free(q->queue);
5607         DIFF_QUEUE_CLEAR(q);
5608         if (options->close_file)
5609                 fclose(options->file);
5610
5611         /*
5612          * Report the content-level differences with HAS_CHANGES;
5613          * diff_addremove/diff_change does not set the bit when
5614          * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
5615          */
5616         if (options->flags.diff_from_contents) {
5617                 if (options->found_changes)
5618                         options->flags.has_changes = 1;
5619                 else
5620                         options->flags.has_changes = 0;
5621         }
5622 }
5623
5624 static int match_filter(const struct diff_options *options, const struct diff_filepair *p)
5625 {
5626         return (((p->status == DIFF_STATUS_MODIFIED) &&
5627                  ((p->score &&
5628                    filter_bit_tst(DIFF_STATUS_FILTER_BROKEN, options)) ||
5629                   (!p->score &&
5630                    filter_bit_tst(DIFF_STATUS_MODIFIED, options)))) ||
5631                 ((p->status != DIFF_STATUS_MODIFIED) &&
5632                  filter_bit_tst(p->status, options)));
5633 }
5634
5635 static void diffcore_apply_filter(struct diff_options *options)
5636 {
5637         int i;
5638         struct diff_queue_struct *q = &diff_queued_diff;
5639         struct diff_queue_struct outq;
5640
5641         DIFF_QUEUE_CLEAR(&outq);
5642
5643         if (!options->filter)
5644                 return;
5645
5646         if (filter_bit_tst(DIFF_STATUS_FILTER_AON, options)) {
5647                 int found;
5648                 for (i = found = 0; !found && i < q->nr; i++) {
5649                         if (match_filter(options, q->queue[i]))
5650                                 found++;
5651                 }
5652                 if (found)
5653                         return;
5654
5655                 /* otherwise we will clear the whole queue
5656                  * by copying the empty outq at the end of this
5657                  * function, but first clear the current entries
5658                  * in the queue.
5659                  */
5660                 for (i = 0; i < q->nr; i++)
5661                         diff_free_filepair(q->queue[i]);
5662         }
5663         else {
5664                 /* Only the matching ones */
5665                 for (i = 0; i < q->nr; i++) {
5666                         struct diff_filepair *p = q->queue[i];
5667                         if (match_filter(options, p))
5668                                 diff_q(&outq, p);
5669                         else
5670                                 diff_free_filepair(p);
5671                 }
5672         }
5673         free(q->queue);
5674         *q = outq;
5675 }
5676
5677 /* Check whether two filespecs with the same mode and size are identical */
5678 static int diff_filespec_is_identical(struct diff_filespec *one,
5679                                       struct diff_filespec *two)
5680 {
5681         if (S_ISGITLINK(one->mode))
5682                 return 0;
5683         if (diff_populate_filespec(one, 0))
5684                 return 0;
5685         if (diff_populate_filespec(two, 0))
5686                 return 0;
5687         return !memcmp(one->data, two->data, one->size);
5688 }
5689
5690 static int diff_filespec_check_stat_unmatch(struct diff_filepair *p)
5691 {
5692         if (p->done_skip_stat_unmatch)
5693                 return p->skip_stat_unmatch_result;
5694
5695         p->done_skip_stat_unmatch = 1;
5696         p->skip_stat_unmatch_result = 0;
5697         /*
5698          * 1. Entries that come from stat info dirtiness
5699          *    always have both sides (iow, not create/delete),
5700          *    one side of the object name is unknown, with
5701          *    the same mode and size.  Keep the ones that
5702          *    do not match these criteria.  They have real
5703          *    differences.
5704          *
5705          * 2. At this point, the file is known to be modified,
5706          *    with the same mode and size, and the object
5707          *    name of one side is unknown.  Need to inspect
5708          *    the identical contents.
5709          */
5710         if (!DIFF_FILE_VALID(p->one) || /* (1) */
5711             !DIFF_FILE_VALID(p->two) ||
5712             (p->one->oid_valid && p->two->oid_valid) ||
5713             (p->one->mode != p->two->mode) ||
5714             diff_populate_filespec(p->one, CHECK_SIZE_ONLY) ||
5715             diff_populate_filespec(p->two, CHECK_SIZE_ONLY) ||
5716             (p->one->size != p->two->size) ||
5717             !diff_filespec_is_identical(p->one, p->two)) /* (2) */
5718                 p->skip_stat_unmatch_result = 1;
5719         return p->skip_stat_unmatch_result;
5720 }
5721
5722 static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
5723 {
5724         int i;
5725         struct diff_queue_struct *q = &diff_queued_diff;
5726         struct diff_queue_struct outq;
5727         DIFF_QUEUE_CLEAR(&outq);
5728
5729         for (i = 0; i < q->nr; i++) {
5730                 struct diff_filepair *p = q->queue[i];
5731
5732                 if (diff_filespec_check_stat_unmatch(p))
5733                         diff_q(&outq, p);
5734                 else {
5735                         /*
5736                          * The caller can subtract 1 from skip_stat_unmatch
5737                          * to determine how many paths were dirty only
5738                          * due to stat info mismatch.
5739                          */
5740                         if (!diffopt->flags.no_index)
5741                                 diffopt->skip_stat_unmatch++;
5742                         diff_free_filepair(p);
5743                 }
5744         }
5745         free(q->queue);
5746         *q = outq;
5747 }
5748
5749 static int diffnamecmp(const void *a_, const void *b_)
5750 {
5751         const struct diff_filepair *a = *((const struct diff_filepair **)a_);
5752         const struct diff_filepair *b = *((const struct diff_filepair **)b_);
5753         const char *name_a, *name_b;
5754
5755         name_a = a->one ? a->one->path : a->two->path;
5756         name_b = b->one ? b->one->path : b->two->path;
5757         return strcmp(name_a, name_b);
5758 }
5759
5760 void diffcore_fix_diff_index(struct diff_options *options)
5761 {
5762         struct diff_queue_struct *q = &diff_queued_diff;
5763         QSORT(q->queue, q->nr, diffnamecmp);
5764 }
5765
5766 void diffcore_std(struct diff_options *options)
5767 {
5768         /* NOTE please keep the following in sync with diff_tree_combined() */
5769         if (options->skip_stat_unmatch)
5770                 diffcore_skip_stat_unmatch(options);
5771         if (!options->found_follow) {
5772                 /* See try_to_follow_renames() in tree-diff.c */
5773                 if (options->break_opt != -1)
5774                         diffcore_break(options->break_opt);
5775                 if (options->detect_rename)
5776                         diffcore_rename(options);
5777                 if (options->break_opt != -1)
5778                         diffcore_merge_broken();
5779         }
5780         if (options->pickaxe)
5781                 diffcore_pickaxe(options);
5782         if (options->orderfile)
5783                 diffcore_order(options->orderfile);
5784         if (!options->found_follow)
5785                 /* See try_to_follow_renames() in tree-diff.c */
5786                 diff_resolve_rename_copy();
5787         diffcore_apply_filter(options);
5788
5789         if (diff_queued_diff.nr && !options->flags.diff_from_contents)
5790                 options->flags.has_changes = 1;
5791         else
5792                 options->flags.has_changes = 0;
5793
5794         options->found_follow = 0;
5795 }
5796
5797 int diff_result_code(struct diff_options *opt, int status)
5798 {
5799         int result = 0;
5800
5801         diff_warn_rename_limit("diff.renameLimit",
5802                                opt->needed_rename_limit,
5803                                opt->degraded_cc_to_c);
5804         if (!opt->flags.exit_with_status &&
5805             !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
5806                 return status;
5807         if (opt->flags.exit_with_status &&
5808             opt->flags.has_changes)
5809                 result |= 01;
5810         if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
5811             opt->flags.check_failed)
5812                 result |= 02;
5813         return result;
5814 }
5815
5816 int diff_can_quit_early(struct diff_options *opt)
5817 {
5818         return (opt->flags.quick &&
5819                 !opt->filter &&
5820                 opt->flags.has_changes);
5821 }
5822
5823 /*
5824  * Shall changes to this submodule be ignored?
5825  *
5826  * Submodule changes can be configured to be ignored separately for each path,
5827  * but that configuration can be overridden from the command line.
5828  */
5829 static int is_submodule_ignored(const char *path, struct diff_options *options)
5830 {
5831         int ignored = 0;
5832         struct diff_flags orig_flags = options->flags;
5833         if (!options->flags.override_submodule_config)
5834                 set_diffopt_flags_from_submodule_config(options, path);
5835         if (options->flags.ignore_submodules)
5836                 ignored = 1;
5837         options->flags = orig_flags;
5838         return ignored;
5839 }
5840
5841 void diff_addremove(struct diff_options *options,
5842                     int addremove, unsigned mode,
5843                     const struct object_id *oid,
5844                     int oid_valid,
5845                     const char *concatpath, unsigned dirty_submodule)
5846 {
5847         struct diff_filespec *one, *two;
5848
5849         if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
5850                 return;
5851
5852         /* This may look odd, but it is a preparation for
5853          * feeding "there are unchanged files which should
5854          * not produce diffs, but when you are doing copy
5855          * detection you would need them, so here they are"
5856          * entries to the diff-core.  They will be prefixed
5857          * with something like '=' or '*' (I haven't decided
5858          * which but should not make any difference).
5859          * Feeding the same new and old to diff_change()
5860          * also has the same effect.
5861          * Before the final output happens, they are pruned after
5862          * merged into rename/copy pairs as appropriate.
5863          */
5864         if (options->flags.reverse_diff)
5865                 addremove = (addremove == '+' ? '-' :
5866                              addremove == '-' ? '+' : addremove);
5867
5868         if (options->prefix &&
5869             strncmp(concatpath, options->prefix, options->prefix_length))
5870                 return;
5871
5872         one = alloc_filespec(concatpath);
5873         two = alloc_filespec(concatpath);
5874
5875         if (addremove != '+')
5876                 fill_filespec(one, oid, oid_valid, mode);
5877         if (addremove != '-') {
5878                 fill_filespec(two, oid, oid_valid, mode);
5879                 two->dirty_submodule = dirty_submodule;
5880         }
5881
5882         diff_queue(&diff_queued_diff, one, two);
5883         if (!options->flags.diff_from_contents)
5884                 options->flags.has_changes = 1;
5885 }
5886
5887 void diff_change(struct diff_options *options,
5888                  unsigned old_mode, unsigned new_mode,
5889                  const struct object_id *old_oid,
5890                  const struct object_id *new_oid,
5891                  int old_oid_valid, int new_oid_valid,
5892                  const char *concatpath,
5893                  unsigned old_dirty_submodule, unsigned new_dirty_submodule)
5894 {
5895         struct diff_filespec *one, *two;
5896         struct diff_filepair *p;
5897
5898         if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
5899             is_submodule_ignored(concatpath, options))
5900                 return;
5901
5902         if (options->flags.reverse_diff) {
5903                 SWAP(old_mode, new_mode);
5904                 SWAP(old_oid, new_oid);
5905                 SWAP(old_oid_valid, new_oid_valid);
5906                 SWAP(old_dirty_submodule, new_dirty_submodule);
5907         }
5908
5909         if (options->prefix &&
5910             strncmp(concatpath, options->prefix, options->prefix_length))
5911                 return;
5912
5913         one = alloc_filespec(concatpath);
5914         two = alloc_filespec(concatpath);
5915         fill_filespec(one, old_oid, old_oid_valid, old_mode);
5916         fill_filespec(two, new_oid, new_oid_valid, new_mode);
5917         one->dirty_submodule = old_dirty_submodule;
5918         two->dirty_submodule = new_dirty_submodule;
5919         p = diff_queue(&diff_queued_diff, one, two);
5920
5921         if (options->flags.diff_from_contents)
5922                 return;
5923
5924         if (options->flags.quick && options->skip_stat_unmatch &&
5925             !diff_filespec_check_stat_unmatch(p))
5926                 return;
5927
5928         options->flags.has_changes = 1;
5929 }
5930
5931 struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
5932 {
5933         struct diff_filepair *pair;
5934         struct diff_filespec *one, *two;
5935
5936         if (options->prefix &&
5937             strncmp(path, options->prefix, options->prefix_length))
5938                 return NULL;
5939
5940         one = alloc_filespec(path);
5941         two = alloc_filespec(path);
5942         pair = diff_queue(&diff_queued_diff, one, two);
5943         pair->is_unmerged = 1;
5944         return pair;
5945 }
5946
5947 static char *run_textconv(const char *pgm, struct diff_filespec *spec,
5948                 size_t *outsize)
5949 {
5950         struct diff_tempfile *temp;
5951         const char *argv[3];
5952         const char **arg = argv;
5953         struct child_process child = CHILD_PROCESS_INIT;
5954         struct strbuf buf = STRBUF_INIT;
5955         int err = 0;
5956
5957         temp = prepare_temp_file(spec->path, spec);
5958         *arg++ = pgm;
5959         *arg++ = temp->name;
5960         *arg = NULL;
5961
5962         child.use_shell = 1;
5963         child.argv = argv;
5964         child.out = -1;
5965         if (start_command(&child)) {
5966                 remove_tempfile();
5967                 return NULL;
5968         }
5969
5970         if (strbuf_read(&buf, child.out, 0) < 0)
5971                 err = error("error reading from textconv command '%s'", pgm);
5972         close(child.out);
5973
5974         if (finish_command(&child) || err) {
5975                 strbuf_release(&buf);
5976                 remove_tempfile();
5977                 return NULL;
5978         }
5979         remove_tempfile();
5980
5981         return strbuf_detach(&buf, outsize);
5982 }
5983
5984 size_t fill_textconv(struct userdiff_driver *driver,
5985                      struct diff_filespec *df,
5986                      char **outbuf)
5987 {
5988         size_t size;
5989
5990         if (!driver) {
5991                 if (!DIFF_FILE_VALID(df)) {
5992                         *outbuf = "";
5993                         return 0;
5994                 }
5995                 if (diff_populate_filespec(df, 0))
5996                         die("unable to read files to diff");
5997                 *outbuf = df->data;
5998                 return df->size;
5999         }
6000
6001         if (!driver->textconv)
6002                 die("BUG: fill_textconv called with non-textconv driver");
6003
6004         if (driver->textconv_cache && df->oid_valid) {
6005                 *outbuf = notes_cache_get(driver->textconv_cache,
6006                                           &df->oid,
6007                                           &size);
6008                 if (*outbuf)
6009                         return size;
6010         }
6011
6012         *outbuf = run_textconv(driver->textconv, df, &size);
6013         if (!*outbuf)
6014                 die("unable to read files to diff");
6015
6016         if (driver->textconv_cache && df->oid_valid) {
6017                 /* ignore errors, as we might be in a readonly repository */
6018                 notes_cache_put(driver->textconv_cache, &df->oid, *outbuf,
6019                                 size);
6020                 /*
6021                  * we could save up changes and flush them all at the end,
6022                  * but we would need an extra call after all diffing is done.
6023                  * Since generating a cache entry is the slow path anyway,
6024                  * this extra overhead probably isn't a big deal.
6025                  */
6026                 notes_cache_write(driver->textconv_cache);
6027         }
6028
6029         return size;
6030 }
6031
6032 int textconv_object(const char *path,
6033                     unsigned mode,
6034                     const struct object_id *oid,
6035                     int oid_valid,
6036                     char **buf,
6037                     unsigned long *buf_size)
6038 {
6039         struct diff_filespec *df;
6040         struct userdiff_driver *textconv;
6041
6042         df = alloc_filespec(path);
6043         fill_filespec(df, oid, oid_valid, mode);
6044         textconv = get_textconv(df);
6045         if (!textconv) {
6046                 free_filespec(df);
6047                 return 0;
6048         }
6049
6050         *buf_size = fill_textconv(textconv, df, buf);
6051         free_filespec(df);
6052         return 1;
6053 }
6054
6055 void setup_diff_pager(struct diff_options *opt)
6056 {
6057         /*
6058          * If the user asked for our exit code, then either they want --quiet
6059          * or --exit-code. We should definitely not bother with a pager in the
6060          * former case, as we will generate no output. Since we still properly
6061          * report our exit code even when a pager is run, we _could_ run a
6062          * pager with --exit-code. But since we have not done so historically,
6063          * and because it is easy to find people oneline advising "git diff
6064          * --exit-code" in hooks and other scripts, we do not do so.
6065          */
6066         if (!opt->flags.exit_with_status &&
6067             check_pager_config("diff") != 0)
6068                 setup_pager();
6069 }