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 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 = DIFF_DETECT_RENAME;
 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                 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         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_word, old_word, 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_word, 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_word, 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_word, 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_word.color = diff_get_color_opt(o, DIFF_FILE_OLD);
1887                 st->new_word.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 void pprint_rename(struct strbuf *name, const char *a, const char *b)
2049 {
2050         const char *old_name = a;
2051         const char *new_name = b;
2052         int pfx_length, sfx_length;
2053         int pfx_adjust_for_slash;
2054         int len_a = strlen(a);
2055         int len_b = strlen(b);
2056         int a_midlen, b_midlen;
2057         int qlen_a = quote_c_style(a, NULL, NULL, 0);
2058         int qlen_b = quote_c_style(b, NULL, NULL, 0);
2059
2060         if (qlen_a || qlen_b) {
2061                 quote_c_style(a, name, NULL, 0);
2062                 strbuf_addstr(name, " => ");
2063                 quote_c_style(b, name, NULL, 0);
2064                 return;
2065         }
2066
2067         /* Find common prefix */
2068         pfx_length = 0;
2069         while (*old_name && *new_name && *old_name == *new_name) {
2070                 if (*old_name == '/')
2071                         pfx_length = old_name - a + 1;
2072                 old_name++;
2073                 new_name++;
2074         }
2075
2076         /* Find common suffix */
2077         old_name = a + len_a;
2078         new_name = b + len_b;
2079         sfx_length = 0;
2080         /*
2081          * If there is a common prefix, it must end in a slash.  In
2082          * that case we let this loop run 1 into the prefix to see the
2083          * same slash.
2084          *
2085          * If there is no common prefix, we cannot do this as it would
2086          * underrun the input strings.
2087          */
2088         pfx_adjust_for_slash = (pfx_length ? 1 : 0);
2089         while (a + pfx_length - pfx_adjust_for_slash <= old_name &&
2090                b + pfx_length - pfx_adjust_for_slash <= new_name &&
2091                *old_name == *new_name) {
2092                 if (*old_name == '/')
2093                         sfx_length = len_a - (old_name - a);
2094                 old_name--;
2095                 new_name--;
2096         }
2097
2098         /*
2099          * pfx{mid-a => mid-b}sfx
2100          * {pfx-a => pfx-b}sfx
2101          * pfx{sfx-a => sfx-b}
2102          * name-a => name-b
2103          */
2104         a_midlen = len_a - pfx_length - sfx_length;
2105         b_midlen = len_b - pfx_length - sfx_length;
2106         if (a_midlen < 0)
2107                 a_midlen = 0;
2108         if (b_midlen < 0)
2109                 b_midlen = 0;
2110
2111         strbuf_grow(name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
2112         if (pfx_length + sfx_length) {
2113                 strbuf_add(name, a, pfx_length);
2114                 strbuf_addch(name, '{');
2115         }
2116         strbuf_add(name, a + pfx_length, a_midlen);
2117         strbuf_addstr(name, " => ");
2118         strbuf_add(name, b + pfx_length, b_midlen);
2119         if (pfx_length + sfx_length) {
2120                 strbuf_addch(name, '}');
2121                 strbuf_add(name, a + len_a - sfx_length, sfx_length);
2122         }
2123 }
2124
2125 struct diffstat_t {
2126         int nr;
2127         int alloc;
2128         struct diffstat_file {
2129                 char *from_name;
2130                 char *name;
2131                 char *print_name;
2132                 const char *comments;
2133                 unsigned is_unmerged:1;
2134                 unsigned is_binary:1;
2135                 unsigned is_renamed:1;
2136                 unsigned is_interesting:1;
2137                 uintmax_t added, deleted;
2138         } **files;
2139 };
2140
2141 static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
2142                                           const char *name_a,
2143                                           const char *name_b)
2144 {
2145         struct diffstat_file *x;
2146         x = xcalloc(1, sizeof(*x));
2147         ALLOC_GROW(diffstat->files, diffstat->nr + 1, diffstat->alloc);
2148         diffstat->files[diffstat->nr++] = x;
2149         if (name_b) {
2150                 x->from_name = xstrdup(name_a);
2151                 x->name = xstrdup(name_b);
2152                 x->is_renamed = 1;
2153         }
2154         else {
2155                 x->from_name = NULL;
2156                 x->name = xstrdup(name_a);
2157         }
2158         return x;
2159 }
2160
2161 static void diffstat_consume(void *priv, char *line, unsigned long len)
2162 {
2163         struct diffstat_t *diffstat = priv;
2164         struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
2165
2166         if (line[0] == '+')
2167                 x->added++;
2168         else if (line[0] == '-')
2169                 x->deleted++;
2170 }
2171
2172 const char mime_boundary_leader[] = "------------";
2173
2174 static int scale_linear(int it, int width, int max_change)
2175 {
2176         if (!it)
2177                 return 0;
2178         /*
2179          * make sure that at least one '-' or '+' is printed if
2180          * there is any change to this path. The easiest way is to
2181          * scale linearly as if the alloted width is one column shorter
2182          * than it is, and then add 1 to the result.
2183          */
2184         return 1 + (it * (width - 1) / max_change);
2185 }
2186
2187 static void show_graph(struct strbuf *out, char ch, int cnt,
2188                        const char *set, const char *reset)
2189 {
2190         if (cnt <= 0)
2191                 return;
2192         strbuf_addstr(out, set);
2193         strbuf_addchars(out, ch, cnt);
2194         strbuf_addstr(out, reset);
2195 }
2196
2197 static void fill_print_name(struct diffstat_file *file)
2198 {
2199         struct strbuf pname = STRBUF_INIT;
2200
2201         if (file->print_name)
2202                 return;
2203
2204         if (file->is_renamed)
2205                 pprint_rename(&pname, file->from_name, file->name);
2206         else
2207                 quote_c_style(file->name, &pname, NULL, 0);
2208
2209         if (file->comments)
2210                 strbuf_addf(&pname, " (%s)", file->comments);
2211
2212         file->print_name = strbuf_detach(&pname, NULL);
2213 }
2214
2215 static void print_stat_summary_inserts_deletes(struct diff_options *options,
2216                 int files, int insertions, int deletions)
2217 {
2218         struct strbuf sb = STRBUF_INIT;
2219
2220         if (!files) {
2221                 assert(insertions == 0 && deletions == 0);
2222                 emit_diff_symbol(options, DIFF_SYMBOL_STATS_SUMMARY_NO_FILES,
2223                                  NULL, 0, 0);
2224                 return;
2225         }
2226
2227         strbuf_addf(&sb,
2228                     (files == 1) ? " %d file changed" : " %d files changed",
2229                     files);
2230
2231         /*
2232          * For binary diff, the caller may want to print "x files
2233          * changed" with insertions == 0 && deletions == 0.
2234          *
2235          * Not omitting "0 insertions(+), 0 deletions(-)" in this case
2236          * is probably less confusing (i.e skip over "2 files changed
2237          * but nothing about added/removed lines? Is this a bug in Git?").
2238          */
2239         if (insertions || deletions == 0) {
2240                 strbuf_addf(&sb,
2241                             (insertions == 1) ? ", %d insertion(+)" : ", %d insertions(+)",
2242                             insertions);
2243         }
2244
2245         if (deletions || insertions == 0) {
2246                 strbuf_addf(&sb,
2247                             (deletions == 1) ? ", %d deletion(-)" : ", %d deletions(-)",
2248                             deletions);
2249         }
2250         strbuf_addch(&sb, '\n');
2251         emit_diff_symbol(options, DIFF_SYMBOL_STATS_SUMMARY_INSERTS_DELETES,
2252                          sb.buf, sb.len, 0);
2253         strbuf_release(&sb);
2254 }
2255
2256 void print_stat_summary(FILE *fp, int files,
2257                         int insertions, int deletions)
2258 {
2259         struct diff_options o;
2260         memset(&o, 0, sizeof(o));
2261         o.file = fp;
2262
2263         print_stat_summary_inserts_deletes(&o, files, insertions, deletions);
2264 }
2265
2266 static void show_stats(struct diffstat_t *data, struct diff_options *options)
2267 {
2268         int i, len, add, del, adds = 0, dels = 0;
2269         uintmax_t max_change = 0, max_len = 0;
2270         int total_files = data->nr, count;
2271         int width, name_width, graph_width, number_width = 0, bin_width = 0;
2272         const char *reset, *add_c, *del_c;
2273         int extra_shown = 0;
2274         const char *line_prefix = diff_line_prefix(options);
2275         struct strbuf out = STRBUF_INIT;
2276
2277         if (data->nr == 0)
2278                 return;
2279
2280         count = options->stat_count ? options->stat_count : data->nr;
2281
2282         reset = diff_get_color_opt(options, DIFF_RESET);
2283         add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
2284         del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
2285
2286         /*
2287          * Find the longest filename and max number of changes
2288          */
2289         for (i = 0; (i < count) && (i < data->nr); i++) {
2290                 struct diffstat_file *file = data->files[i];
2291                 uintmax_t change = file->added + file->deleted;
2292
2293                 if (!file->is_interesting && (change == 0)) {
2294                         count++; /* not shown == room for one more */
2295                         continue;
2296                 }
2297                 fill_print_name(file);
2298                 len = strlen(file->print_name);
2299                 if (max_len < len)
2300                         max_len = len;
2301
2302                 if (file->is_unmerged) {
2303                         /* "Unmerged" is 8 characters */
2304                         bin_width = bin_width < 8 ? 8 : bin_width;
2305                         continue;
2306                 }
2307                 if (file->is_binary) {
2308                         /* "Bin XXX -> YYY bytes" */
2309                         int w = 14 + decimal_width(file->added)
2310                                 + decimal_width(file->deleted);
2311                         bin_width = bin_width < w ? w : bin_width;
2312                         /* Display change counts aligned with "Bin" */
2313                         number_width = 3;
2314                         continue;
2315                 }
2316
2317                 if (max_change < change)
2318                         max_change = change;
2319         }
2320         count = i; /* where we can stop scanning in data->files[] */
2321
2322         /*
2323          * We have width = stat_width or term_columns() columns total.
2324          * We want a maximum of min(max_len, stat_name_width) for the name part.
2325          * We want a maximum of min(max_change, stat_graph_width) for the +- part.
2326          * We also need 1 for " " and 4 + decimal_width(max_change)
2327          * for " | NNNN " and one the empty column at the end, altogether
2328          * 6 + decimal_width(max_change).
2329          *
2330          * If there's not enough space, we will use the smaller of
2331          * stat_name_width (if set) and 5/8*width for the filename,
2332          * and the rest for constant elements + graph part, but no more
2333          * than stat_graph_width for the graph part.
2334          * (5/8 gives 50 for filename and 30 for the constant parts + graph
2335          * for the standard terminal size).
2336          *
2337          * In other words: stat_width limits the maximum width, and
2338          * stat_name_width fixes the maximum width of the filename,
2339          * and is also used to divide available columns if there
2340          * aren't enough.
2341          *
2342          * Binary files are displayed with "Bin XXX -> YYY bytes"
2343          * instead of the change count and graph. This part is treated
2344          * similarly to the graph part, except that it is not
2345          * "scaled". If total width is too small to accommodate the
2346          * guaranteed minimum width of the filename part and the
2347          * separators and this message, this message will "overflow"
2348          * making the line longer than the maximum width.
2349          */
2350
2351         if (options->stat_width == -1)
2352                 width = term_columns() - strlen(line_prefix);
2353         else
2354                 width = options->stat_width ? options->stat_width : 80;
2355         number_width = decimal_width(max_change) > number_width ?
2356                 decimal_width(max_change) : number_width;
2357
2358         if (options->stat_graph_width == -1)
2359                 options->stat_graph_width = diff_stat_graph_width;
2360
2361         /*
2362          * Guarantee 3/8*16==6 for the graph part
2363          * and 5/8*16==10 for the filename part
2364          */
2365         if (width < 16 + 6 + number_width)
2366                 width = 16 + 6 + number_width;
2367
2368         /*
2369          * First assign sizes that are wanted, ignoring available width.
2370          * strlen("Bin XXX -> YYY bytes") == bin_width, and the part
2371          * starting from "XXX" should fit in graph_width.
2372          */
2373         graph_width = max_change + 4 > bin_width ? max_change : bin_width - 4;
2374         if (options->stat_graph_width &&
2375             options->stat_graph_width < graph_width)
2376                 graph_width = options->stat_graph_width;
2377
2378         name_width = (options->stat_name_width > 0 &&
2379                       options->stat_name_width < max_len) ?
2380                 options->stat_name_width : max_len;
2381
2382         /*
2383          * Adjust adjustable widths not to exceed maximum width
2384          */
2385         if (name_width + number_width + 6 + graph_width > width) {
2386                 if (graph_width > width * 3/8 - number_width - 6) {
2387                         graph_width = width * 3/8 - number_width - 6;
2388                         if (graph_width < 6)
2389                                 graph_width = 6;
2390                 }
2391
2392                 if (options->stat_graph_width &&
2393                     graph_width > options->stat_graph_width)
2394                         graph_width = options->stat_graph_width;
2395                 if (name_width > width - number_width - 6 - graph_width)
2396                         name_width = width - number_width - 6 - graph_width;
2397                 else
2398                         graph_width = width - number_width - 6 - name_width;
2399         }
2400
2401         /*
2402          * From here name_width is the width of the name area,
2403          * and graph_width is the width of the graph area.
2404          * max_change is used to scale graph properly.
2405          */
2406         for (i = 0; i < count; i++) {
2407                 const char *prefix = "";
2408                 struct diffstat_file *file = data->files[i];
2409                 char *name = file->print_name;
2410                 uintmax_t added = file->added;
2411                 uintmax_t deleted = file->deleted;
2412                 int name_len;
2413
2414                 if (!file->is_interesting && (added + deleted == 0))
2415                         continue;
2416
2417                 /*
2418                  * "scale" the filename
2419                  */
2420                 len = name_width;
2421                 name_len = strlen(name);
2422                 if (name_width < name_len) {
2423                         char *slash;
2424                         prefix = "...";
2425                         len -= 3;
2426                         name += name_len - len;
2427                         slash = strchr(name, '/');
2428                         if (slash)
2429                                 name = slash;
2430                 }
2431
2432                 if (file->is_binary) {
2433                         strbuf_addf(&out, " %s%-*s |", prefix, len, name);
2434                         strbuf_addf(&out, " %*s", number_width, "Bin");
2435                         if (!added && !deleted) {
2436                                 strbuf_addch(&out, '\n');
2437                                 emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2438                                                  out.buf, out.len, 0);
2439                                 strbuf_reset(&out);
2440                                 continue;
2441                         }
2442                         strbuf_addf(&out, " %s%"PRIuMAX"%s",
2443                                 del_c, deleted, reset);
2444                         strbuf_addstr(&out, " -> ");
2445                         strbuf_addf(&out, "%s%"PRIuMAX"%s",
2446                                 add_c, added, reset);
2447                         strbuf_addstr(&out, " bytes\n");
2448                         emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2449                                          out.buf, out.len, 0);
2450                         strbuf_reset(&out);
2451                         continue;
2452                 }
2453                 else if (file->is_unmerged) {
2454                         strbuf_addf(&out, " %s%-*s |", prefix, len, name);
2455                         strbuf_addstr(&out, " Unmerged\n");
2456                         emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2457                                          out.buf, out.len, 0);
2458                         strbuf_reset(&out);
2459                         continue;
2460                 }
2461
2462                 /*
2463                  * scale the add/delete
2464                  */
2465                 add = added;
2466                 del = deleted;
2467
2468                 if (graph_width <= max_change) {
2469                         int total = scale_linear(add + del, graph_width, max_change);
2470                         if (total < 2 && add && del)
2471                                 /* width >= 2 due to the sanity check */
2472                                 total = 2;
2473                         if (add < del) {
2474                                 add = scale_linear(add, graph_width, max_change);
2475                                 del = total - add;
2476                         } else {
2477                                 del = scale_linear(del, graph_width, max_change);
2478                                 add = total - del;
2479                         }
2480                 }
2481                 strbuf_addf(&out, " %s%-*s |", prefix, len, name);
2482                 strbuf_addf(&out, " %*"PRIuMAX"%s",
2483                         number_width, added + deleted,
2484                         added + deleted ? " " : "");
2485                 show_graph(&out, '+', add, add_c, reset);
2486                 show_graph(&out, '-', del, del_c, reset);
2487                 strbuf_addch(&out, '\n');
2488                 emit_diff_symbol(options, DIFF_SYMBOL_STATS_LINE,
2489                                  out.buf, out.len, 0);
2490                 strbuf_reset(&out);
2491         }
2492
2493         for (i = 0; i < data->nr; i++) {
2494                 struct diffstat_file *file = data->files[i];
2495                 uintmax_t added = file->added;
2496                 uintmax_t deleted = file->deleted;
2497
2498                 if (file->is_unmerged ||
2499                     (!file->is_interesting && (added + deleted == 0))) {
2500                         total_files--;
2501                         continue;
2502                 }
2503
2504                 if (!file->is_binary) {
2505                         adds += added;
2506                         dels += deleted;
2507                 }
2508                 if (i < count)
2509                         continue;
2510                 if (!extra_shown)
2511                         emit_diff_symbol(options,
2512                                          DIFF_SYMBOL_STATS_SUMMARY_ABBREV,
2513                                          NULL, 0, 0);
2514                 extra_shown = 1;
2515         }
2516
2517         print_stat_summary_inserts_deletes(options, total_files, adds, dels);
2518         strbuf_release(&out);
2519 }
2520
2521 static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
2522 {
2523         int i, adds = 0, dels = 0, total_files = data->nr;
2524
2525         if (data->nr == 0)
2526                 return;
2527
2528         for (i = 0; i < data->nr; i++) {
2529                 int added = data->files[i]->added;
2530                 int deleted = data->files[i]->deleted;
2531
2532                 if (data->files[i]->is_unmerged ||
2533                     (!data->files[i]->is_interesting && (added + deleted == 0))) {
2534                         total_files--;
2535                 } else if (!data->files[i]->is_binary) { /* don't count bytes */
2536                         adds += added;
2537                         dels += deleted;
2538                 }
2539         }
2540         print_stat_summary_inserts_deletes(options, total_files, adds, dels);
2541 }
2542
2543 static void show_numstat(struct diffstat_t *data, struct diff_options *options)
2544 {
2545         int i;
2546
2547         if (data->nr == 0)
2548                 return;
2549
2550         for (i = 0; i < data->nr; i++) {
2551                 struct diffstat_file *file = data->files[i];
2552
2553                 fprintf(options->file, "%s", diff_line_prefix(options));
2554
2555                 if (file->is_binary)
2556                         fprintf(options->file, "-\t-\t");
2557                 else
2558                         fprintf(options->file,
2559                                 "%"PRIuMAX"\t%"PRIuMAX"\t",
2560                                 file->added, file->deleted);
2561                 if (options->line_termination) {
2562                         fill_print_name(file);
2563                         if (!file->is_renamed)
2564                                 write_name_quoted(file->name, options->file,
2565                                                   options->line_termination);
2566                         else {
2567                                 fputs(file->print_name, options->file);
2568                                 putc(options->line_termination, options->file);
2569                         }
2570                 } else {
2571                         if (file->is_renamed) {
2572                                 putc('\0', options->file);
2573                                 write_name_quoted(file->from_name, options->file, '\0');
2574                         }
2575                         write_name_quoted(file->name, options->file, '\0');
2576                 }
2577         }
2578 }
2579
2580 struct dirstat_file {
2581         const char *name;
2582         unsigned long changed;
2583 };
2584
2585 struct dirstat_dir {
2586         struct dirstat_file *files;
2587         int alloc, nr, permille, cumulative;
2588 };
2589
2590 static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
2591                 unsigned long changed, const char *base, int baselen)
2592 {
2593         unsigned long sum_changes = 0;
2594         unsigned int sources = 0;
2595         const char *line_prefix = diff_line_prefix(opt);
2596
2597         while (dir->nr) {
2598                 struct dirstat_file *f = dir->files;
2599                 int namelen = strlen(f->name);
2600                 unsigned long changes;
2601                 char *slash;
2602
2603                 if (namelen < baselen)
2604                         break;
2605                 if (memcmp(f->name, base, baselen))
2606                         break;
2607                 slash = strchr(f->name + baselen, '/');
2608                 if (slash) {
2609                         int newbaselen = slash + 1 - f->name;
2610                         changes = gather_dirstat(opt, dir, changed, f->name, newbaselen);
2611                         sources++;
2612                 } else {
2613                         changes = f->changed;
2614                         dir->files++;
2615                         dir->nr--;
2616                         sources += 2;
2617                 }
2618                 sum_changes += changes;
2619         }
2620
2621         /*
2622          * We don't report dirstat's for
2623          *  - the top level
2624          *  - or cases where everything came from a single directory
2625          *    under this directory (sources == 1).
2626          */
2627         if (baselen && sources != 1) {
2628                 if (sum_changes) {
2629                         int permille = sum_changes * 1000 / changed;
2630                         if (permille >= dir->permille) {
2631                                 fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
2632                                         permille / 10, permille % 10, baselen, base);
2633                                 if (!dir->cumulative)
2634                                         return 0;
2635                         }
2636                 }
2637         }
2638         return sum_changes;
2639 }
2640
2641 static int dirstat_compare(const void *_a, const void *_b)
2642 {
2643         const struct dirstat_file *a = _a;
2644         const struct dirstat_file *b = _b;
2645         return strcmp(a->name, b->name);
2646 }
2647
2648 static void show_dirstat(struct diff_options *options)
2649 {
2650         int i;
2651         unsigned long changed;
2652         struct dirstat_dir dir;
2653         struct diff_queue_struct *q = &diff_queued_diff;
2654
2655         dir.files = NULL;
2656         dir.alloc = 0;
2657         dir.nr = 0;
2658         dir.permille = options->dirstat_permille;
2659         dir.cumulative = options->flags.dirstat_cumulative;
2660
2661         changed = 0;
2662         for (i = 0; i < q->nr; i++) {
2663                 struct diff_filepair *p = q->queue[i];
2664                 const char *name;
2665                 unsigned long copied, added, damage;
2666                 int content_changed;
2667
2668                 name = p->two->path ? p->two->path : p->one->path;
2669
2670                 if (p->one->oid_valid && p->two->oid_valid)
2671                         content_changed = oidcmp(&p->one->oid, &p->two->oid);
2672                 else
2673                         content_changed = 1;
2674
2675                 if (!content_changed) {
2676                         /*
2677                          * The SHA1 has not changed, so pre-/post-content is
2678                          * identical. We can therefore skip looking at the
2679                          * file contents altogether.
2680                          */
2681                         damage = 0;
2682                         goto found_damage;
2683                 }
2684
2685                 if (options->flags.dirstat_by_file) {
2686                         /*
2687                          * In --dirstat-by-file mode, we don't really need to
2688                          * look at the actual file contents at all.
2689                          * The fact that the SHA1 changed is enough for us to
2690                          * add this file to the list of results
2691                          * (with each file contributing equal damage).
2692                          */
2693                         damage = 1;
2694                         goto found_damage;
2695                 }
2696
2697                 if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
2698                         diff_populate_filespec(p->one, 0);
2699                         diff_populate_filespec(p->two, 0);
2700                         diffcore_count_changes(p->one, p->two, NULL, NULL,
2701                                                &copied, &added);
2702                         diff_free_filespec_data(p->one);
2703                         diff_free_filespec_data(p->two);
2704                 } else if (DIFF_FILE_VALID(p->one)) {
2705                         diff_populate_filespec(p->one, CHECK_SIZE_ONLY);
2706                         copied = added = 0;
2707                         diff_free_filespec_data(p->one);
2708                 } else if (DIFF_FILE_VALID(p->two)) {
2709                         diff_populate_filespec(p->two, CHECK_SIZE_ONLY);
2710                         copied = 0;
2711                         added = p->two->size;
2712                         diff_free_filespec_data(p->two);
2713                 } else
2714                         continue;
2715
2716                 /*
2717                  * Original minus copied is the removed material,
2718                  * added is the new material.  They are both damages
2719                  * made to the preimage.
2720                  * If the resulting damage is zero, we know that
2721                  * diffcore_count_changes() considers the two entries to
2722                  * be identical, but since content_changed is true, we
2723                  * know that there must have been _some_ kind of change,
2724                  * so we force all entries to have damage > 0.
2725                  */
2726                 damage = (p->one->size - copied) + added;
2727                 if (!damage)
2728                         damage = 1;
2729
2730 found_damage:
2731                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
2732                 dir.files[dir.nr].name = name;
2733                 dir.files[dir.nr].changed = damage;
2734                 changed += damage;
2735                 dir.nr++;
2736         }
2737
2738         /* This can happen even with many files, if everything was renames */
2739         if (!changed)
2740                 return;
2741
2742         /* Show all directories with more than x% of the changes */
2743         QSORT(dir.files, dir.nr, dirstat_compare);
2744         gather_dirstat(options, &dir, changed, "", 0);
2745 }
2746
2747 static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
2748 {
2749         int i;
2750         unsigned long changed;
2751         struct dirstat_dir dir;
2752
2753         if (data->nr == 0)
2754                 return;
2755
2756         dir.files = NULL;
2757         dir.alloc = 0;
2758         dir.nr = 0;
2759         dir.permille = options->dirstat_permille;
2760         dir.cumulative = options->flags.dirstat_cumulative;
2761
2762         changed = 0;
2763         for (i = 0; i < data->nr; i++) {
2764                 struct diffstat_file *file = data->files[i];
2765                 unsigned long damage = file->added + file->deleted;
2766                 if (file->is_binary)
2767                         /*
2768                          * binary files counts bytes, not lines. Must find some
2769                          * way to normalize binary bytes vs. textual lines.
2770                          * The following heuristic assumes that there are 64
2771                          * bytes per "line".
2772                          * This is stupid and ugly, but very cheap...
2773                          */
2774                         damage = DIV_ROUND_UP(damage, 64);
2775                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
2776                 dir.files[dir.nr].name = file->name;
2777                 dir.files[dir.nr].changed = damage;
2778                 changed += damage;
2779                 dir.nr++;
2780         }
2781
2782         /* This can happen even with many files, if everything was renames */
2783         if (!changed)
2784                 return;
2785
2786         /* Show all directories with more than x% of the changes */
2787         QSORT(dir.files, dir.nr, dirstat_compare);
2788         gather_dirstat(options, &dir, changed, "", 0);
2789 }
2790
2791 static void free_diffstat_info(struct diffstat_t *diffstat)
2792 {
2793         int i;
2794         for (i = 0; i < diffstat->nr; i++) {
2795                 struct diffstat_file *f = diffstat->files[i];
2796                 free(f->print_name);
2797                 free(f->name);
2798                 free(f->from_name);
2799                 free(f);
2800         }
2801         free(diffstat->files);
2802 }
2803
2804 struct checkdiff_t {
2805         const char *filename;
2806         int lineno;
2807         int conflict_marker_size;
2808         struct diff_options *o;
2809         unsigned ws_rule;
2810         unsigned status;
2811 };
2812
2813 static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
2814 {
2815         char firstchar;
2816         int cnt;
2817
2818         if (len < marker_size + 1)
2819                 return 0;
2820         firstchar = line[0];
2821         switch (firstchar) {
2822         case '=': case '>': case '<': case '|':
2823                 break;
2824         default:
2825                 return 0;
2826         }
2827         for (cnt = 1; cnt < marker_size; cnt++)
2828                 if (line[cnt] != firstchar)
2829                         return 0;
2830         /* line[1] thru line[marker_size-1] are same as firstchar */
2831         if (len < marker_size + 1 || !isspace(line[marker_size]))
2832                 return 0;
2833         return 1;
2834 }
2835
2836 static void checkdiff_consume(void *priv, char *line, unsigned long len)
2837 {
2838         struct checkdiff_t *data = priv;
2839         int marker_size = data->conflict_marker_size;
2840         const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
2841         const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
2842         const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
2843         char *err;
2844         const char *line_prefix;
2845
2846         assert(data->o);
2847         line_prefix = diff_line_prefix(data->o);
2848
2849         if (line[0] == '+') {
2850                 unsigned bad;
2851                 data->lineno++;
2852                 if (is_conflict_marker(line + 1, marker_size, len - 1)) {
2853                         data->status |= 1;
2854                         fprintf(data->o->file,
2855                                 "%s%s:%d: leftover conflict marker\n",
2856                                 line_prefix, data->filename, data->lineno);
2857                 }
2858                 bad = ws_check(line + 1, len - 1, data->ws_rule);
2859                 if (!bad)
2860                         return;
2861                 data->status |= bad;
2862                 err = whitespace_error_string(bad);
2863                 fprintf(data->o->file, "%s%s:%d: %s.\n",
2864                         line_prefix, data->filename, data->lineno, err);
2865                 free(err);
2866                 emit_line(data->o, set, reset, line, 1);
2867                 ws_check_emit(line + 1, len - 1, data->ws_rule,
2868                               data->o->file, set, reset, ws);
2869         } else if (line[0] == ' ') {
2870                 data->lineno++;
2871         } else if (line[0] == '@') {
2872                 char *plus = strchr(line, '+');
2873                 if (plus)
2874                         data->lineno = strtol(plus, NULL, 10) - 1;
2875                 else
2876                         die("invalid diff");
2877         }
2878 }
2879
2880 static unsigned char *deflate_it(char *data,
2881                                  unsigned long size,
2882                                  unsigned long *result_size)
2883 {
2884         int bound;
2885         unsigned char *deflated;
2886         git_zstream stream;
2887
2888         git_deflate_init(&stream, zlib_compression_level);
2889         bound = git_deflate_bound(&stream, size);
2890         deflated = xmalloc(bound);
2891         stream.next_out = deflated;
2892         stream.avail_out = bound;
2893
2894         stream.next_in = (unsigned char *)data;
2895         stream.avail_in = size;
2896         while (git_deflate(&stream, Z_FINISH) == Z_OK)
2897                 ; /* nothing */
2898         git_deflate_end(&stream);
2899         *result_size = stream.total_out;
2900         return deflated;
2901 }
2902
2903 static void emit_binary_diff_body(struct diff_options *o,
2904                                   mmfile_t *one, mmfile_t *two)
2905 {
2906         void *cp;
2907         void *delta;
2908         void *deflated;
2909         void *data;
2910         unsigned long orig_size;
2911         unsigned long delta_size;
2912         unsigned long deflate_size;
2913         unsigned long data_size;
2914
2915         /* We could do deflated delta, or we could do just deflated two,
2916          * whichever is smaller.
2917          */
2918         delta = NULL;
2919         deflated = deflate_it(two->ptr, two->size, &deflate_size);
2920         if (one->size && two->size) {
2921                 delta = diff_delta(one->ptr, one->size,
2922                                    two->ptr, two->size,
2923                                    &delta_size, deflate_size);
2924                 if (delta) {
2925                         void *to_free = delta;
2926                         orig_size = delta_size;
2927                         delta = deflate_it(delta, delta_size, &delta_size);
2928                         free(to_free);
2929                 }
2930         }
2931
2932         if (delta && delta_size < deflate_size) {
2933                 char *s = xstrfmt("%lu", orig_size);
2934                 emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_HEADER_DELTA,
2935                                  s, strlen(s), 0);
2936                 free(s);
2937                 free(deflated);
2938                 data = delta;
2939                 data_size = delta_size;
2940         } else {
2941                 char *s = xstrfmt("%lu", two->size);
2942                 emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_HEADER_LITERAL,
2943                                  s, strlen(s), 0);
2944                 free(s);
2945                 free(delta);
2946                 data = deflated;
2947                 data_size = deflate_size;
2948         }
2949
2950         /* emit data encoded in base85 */
2951         cp = data;
2952         while (data_size) {
2953                 int len;
2954                 int bytes = (52 < data_size) ? 52 : data_size;
2955                 char line[71];
2956                 data_size -= bytes;
2957                 if (bytes <= 26)
2958                         line[0] = bytes + 'A' - 1;
2959                 else
2960                         line[0] = bytes - 26 + 'a' - 1;
2961                 encode_85(line + 1, cp, bytes);
2962                 cp = (char *) cp + bytes;
2963
2964                 len = strlen(line);
2965                 line[len++] = '\n';
2966                 line[len] = '\0';
2967
2968                 emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_BODY,
2969                                  line, len, 0);
2970         }
2971         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_FOOTER, NULL, 0, 0);
2972         free(data);
2973 }
2974
2975 static void emit_binary_diff(struct diff_options *o,
2976                              mmfile_t *one, mmfile_t *two)
2977 {
2978         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_DIFF_HEADER, NULL, 0, 0);
2979         emit_binary_diff_body(o, one, two);
2980         emit_binary_diff_body(o, two, one);
2981 }
2982
2983 int diff_filespec_is_binary(struct diff_filespec *one)
2984 {
2985         if (one->is_binary == -1) {
2986                 diff_filespec_load_driver(one);
2987                 if (one->driver->binary != -1)
2988                         one->is_binary = one->driver->binary;
2989                 else {
2990                         if (!one->data && DIFF_FILE_VALID(one))
2991                                 diff_populate_filespec(one, CHECK_BINARY);
2992                         if (one->is_binary == -1 && one->data)
2993                                 one->is_binary = buffer_is_binary(one->data,
2994                                                 one->size);
2995                         if (one->is_binary == -1)
2996                                 one->is_binary = 0;
2997                 }
2998         }
2999         return one->is_binary;
3000 }
3001
3002 static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
3003 {
3004         diff_filespec_load_driver(one);
3005         return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
3006 }
3007
3008 void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
3009 {
3010         if (!options->a_prefix)
3011                 options->a_prefix = a;
3012         if (!options->b_prefix)
3013                 options->b_prefix = b;
3014 }
3015
3016 struct userdiff_driver *get_textconv(struct diff_filespec *one)
3017 {
3018         if (!DIFF_FILE_VALID(one))
3019                 return NULL;
3020
3021         diff_filespec_load_driver(one);
3022         return userdiff_get_textconv(one->driver);
3023 }
3024
3025 static void builtin_diff(const char *name_a,
3026                          const char *name_b,
3027                          struct diff_filespec *one,
3028                          struct diff_filespec *two,
3029                          const char *xfrm_msg,
3030                          int must_show_header,
3031                          struct diff_options *o,
3032                          int complete_rewrite)
3033 {
3034         mmfile_t mf1, mf2;
3035         const char *lbl[2];
3036         char *a_one, *b_two;
3037         const char *meta = diff_get_color_opt(o, DIFF_METAINFO);
3038         const char *reset = diff_get_color_opt(o, DIFF_RESET);
3039         const char *a_prefix, *b_prefix;
3040         struct userdiff_driver *textconv_one = NULL;
3041         struct userdiff_driver *textconv_two = NULL;
3042         struct strbuf header = STRBUF_INIT;
3043         const char *line_prefix = diff_line_prefix(o);
3044
3045         diff_set_mnemonic_prefix(o, "a/", "b/");
3046         if (o->flags.reverse_diff) {
3047                 a_prefix = o->b_prefix;
3048                 b_prefix = o->a_prefix;
3049         } else {
3050                 a_prefix = o->a_prefix;
3051                 b_prefix = o->b_prefix;
3052         }
3053
3054         if (o->submodule_format == DIFF_SUBMODULE_LOG &&
3055             (!one->mode || S_ISGITLINK(one->mode)) &&
3056             (!two->mode || S_ISGITLINK(two->mode))) {
3057                 show_submodule_summary(o, one->path ? one->path : two->path,
3058                                 &one->oid, &two->oid,
3059                                 two->dirty_submodule);
3060                 return;
3061         } else if (o->submodule_format == DIFF_SUBMODULE_INLINE_DIFF &&
3062                    (!one->mode || S_ISGITLINK(one->mode)) &&
3063                    (!two->mode || S_ISGITLINK(two->mode))) {
3064                 show_submodule_inline_diff(o, one->path ? one->path : two->path,
3065                                 &one->oid, &two->oid,
3066                                 two->dirty_submodule);
3067                 return;
3068         }
3069
3070         if (o->flags.allow_textconv) {
3071                 textconv_one = get_textconv(one);
3072                 textconv_two = get_textconv(two);
3073         }
3074
3075         /* Never use a non-valid filename anywhere if at all possible */
3076         name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
3077         name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
3078
3079         a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
3080         b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
3081         lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
3082         lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
3083         strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, meta, a_one, b_two, reset);
3084         if (lbl[0][0] == '/') {
3085                 /* /dev/null */
3086                 strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, meta, two->mode, reset);
3087                 if (xfrm_msg)
3088                         strbuf_addstr(&header, xfrm_msg);
3089                 must_show_header = 1;
3090         }
3091         else if (lbl[1][0] == '/') {
3092                 strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, meta, one->mode, reset);
3093                 if (xfrm_msg)
3094                         strbuf_addstr(&header, xfrm_msg);
3095                 must_show_header = 1;
3096         }
3097         else {
3098                 if (one->mode != two->mode) {
3099                         strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, meta, one->mode, reset);
3100                         strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, meta, two->mode, reset);
3101                         must_show_header = 1;
3102                 }
3103                 if (xfrm_msg)
3104                         strbuf_addstr(&header, xfrm_msg);
3105
3106                 /*
3107                  * we do not run diff between different kind
3108                  * of objects.
3109                  */
3110                 if ((one->mode ^ two->mode) & S_IFMT)
3111                         goto free_ab_and_return;
3112                 if (complete_rewrite &&
3113                     (textconv_one || !diff_filespec_is_binary(one)) &&
3114                     (textconv_two || !diff_filespec_is_binary(two))) {
3115                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3116                                          header.buf, header.len, 0);
3117                         strbuf_reset(&header);
3118                         emit_rewrite_diff(name_a, name_b, one, two,
3119                                                 textconv_one, textconv_two, o);
3120                         o->found_changes = 1;
3121                         goto free_ab_and_return;
3122                 }
3123         }
3124
3125         if (o->irreversible_delete && lbl[1][0] == '/') {
3126                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER, header.buf,
3127                                  header.len, 0);
3128                 strbuf_reset(&header);
3129                 goto free_ab_and_return;
3130         } else if (!o->flags.text &&
3131             ( (!textconv_one && diff_filespec_is_binary(one)) ||
3132               (!textconv_two && diff_filespec_is_binary(two)) )) {
3133                 struct strbuf sb = STRBUF_INIT;
3134                 if (!one->data && !two->data &&
3135                     S_ISREG(one->mode) && S_ISREG(two->mode) &&
3136                     !o->flags.binary) {
3137                         if (!oidcmp(&one->oid, &two->oid)) {
3138                                 if (must_show_header)
3139                                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3140                                                          header.buf, header.len,
3141                                                          0);
3142                                 goto free_ab_and_return;
3143                         }
3144                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3145                                          header.buf, header.len, 0);
3146                         strbuf_addf(&sb, "%sBinary files %s and %s differ\n",
3147                                     diff_line_prefix(o), lbl[0], lbl[1]);
3148                         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_FILES,
3149                                          sb.buf, sb.len, 0);
3150                         strbuf_release(&sb);
3151                         goto free_ab_and_return;
3152                 }
3153                 if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
3154                         die("unable to read files to diff");
3155                 /* Quite common confusing case */
3156                 if (mf1.size == mf2.size &&
3157                     !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
3158                         if (must_show_header)
3159                                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3160                                                  header.buf, header.len, 0);
3161                         goto free_ab_and_return;
3162                 }
3163                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER, header.buf, header.len, 0);
3164                 strbuf_reset(&header);
3165                 if (o->flags.binary)
3166                         emit_binary_diff(o, &mf1, &mf2);
3167                 else {
3168                         strbuf_addf(&sb, "%sBinary files %s and %s differ\n",
3169                                     diff_line_prefix(o), lbl[0], lbl[1]);
3170                         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_FILES,
3171                                          sb.buf, sb.len, 0);
3172                         strbuf_release(&sb);
3173                 }
3174                 o->found_changes = 1;
3175         } else {
3176                 /* Crazy xdl interfaces.. */
3177                 const char *diffopts = getenv("GIT_DIFF_OPTS");
3178                 const char *v;
3179                 xpparam_t xpp;
3180                 xdemitconf_t xecfg;
3181                 struct emit_callback ecbdata;
3182                 const struct userdiff_funcname *pe;
3183
3184                 if (must_show_header) {
3185                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
3186                                          header.buf, header.len, 0);
3187                         strbuf_reset(&header);
3188                 }
3189
3190                 mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
3191                 mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
3192
3193                 pe = diff_funcname_pattern(one);
3194                 if (!pe)
3195                         pe = diff_funcname_pattern(two);
3196
3197                 memset(&xpp, 0, sizeof(xpp));
3198                 memset(&xecfg, 0, sizeof(xecfg));
3199                 memset(&ecbdata, 0, sizeof(ecbdata));
3200                 ecbdata.label_path = lbl;
3201                 ecbdata.color_diff = want_color(o->use_color);
3202                 ecbdata.ws_rule = whitespace_rule(name_b);
3203                 if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
3204                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
3205                 ecbdata.opt = o;
3206                 ecbdata.header = header.len ? &header : NULL;
3207                 xpp.flags = o->xdl_opts;
3208                 xpp.anchors = o->anchors;
3209                 xpp.anchors_nr = o->anchors_nr;
3210                 xecfg.ctxlen = o->context;
3211                 xecfg.interhunkctxlen = o->interhunkcontext;
3212                 xecfg.flags = XDL_EMIT_FUNCNAMES;
3213                 if (o->flags.funccontext)
3214                         xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
3215                 if (pe)
3216                         xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
3217                 if (!diffopts)
3218                         ;
3219                 else if (skip_prefix(diffopts, "--unified=", &v))
3220                         xecfg.ctxlen = strtoul(v, NULL, 10);
3221                 else if (skip_prefix(diffopts, "-u", &v))
3222                         xecfg.ctxlen = strtoul(v, NULL, 10);
3223                 if (o->word_diff)
3224                         init_diff_words_data(&ecbdata, o, one, two);
3225                 if (xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
3226                                   &xpp, &xecfg))
3227                         die("unable to generate diff for %s", one->path);
3228                 if (o->word_diff)
3229                         free_diff_words_data(&ecbdata);
3230                 if (textconv_one)
3231                         free(mf1.ptr);
3232                 if (textconv_two)
3233                         free(mf2.ptr);
3234                 xdiff_clear_find_func(&xecfg);
3235         }
3236
3237  free_ab_and_return:
3238         strbuf_release(&header);
3239         diff_free_filespec_data(one);
3240         diff_free_filespec_data(two);
3241         free(a_one);
3242         free(b_two);
3243         return;
3244 }
3245
3246 static char *get_compact_summary(const struct diff_filepair *p, int is_renamed)
3247 {
3248         if (!is_renamed) {
3249                 if (p->status == DIFF_STATUS_ADDED) {
3250                         if (S_ISLNK(p->two->mode))
3251                                 return "new +l";
3252                         else if ((p->two->mode & 0777) == 0755)
3253                                 return "new +x";
3254                         else
3255                                 return "new";
3256                 } else if (p->status == DIFF_STATUS_DELETED)
3257                         return "gone";
3258         }
3259         if (S_ISLNK(p->one->mode) && !S_ISLNK(p->two->mode))
3260                 return "mode -l";
3261         else if (!S_ISLNK(p->one->mode) && S_ISLNK(p->two->mode))
3262                 return "mode +l";
3263         else if ((p->one->mode & 0777) == 0644 &&
3264                  (p->two->mode & 0777) == 0755)
3265                 return "mode +x";
3266         else if ((p->one->mode & 0777) == 0755 &&
3267                  (p->two->mode & 0777) == 0644)
3268                 return "mode -x";
3269         return NULL;
3270 }
3271
3272 static void builtin_diffstat(const char *name_a, const char *name_b,
3273                              struct diff_filespec *one,
3274                              struct diff_filespec *two,
3275                              struct diffstat_t *diffstat,
3276                              struct diff_options *o,
3277                              struct diff_filepair *p)
3278 {
3279         mmfile_t mf1, mf2;
3280         struct diffstat_file *data;
3281         int same_contents;
3282         int complete_rewrite = 0;
3283
3284         if (!DIFF_PAIR_UNMERGED(p)) {
3285                 if (p->status == DIFF_STATUS_MODIFIED && p->score)
3286                         complete_rewrite = 1;
3287         }
3288
3289         data = diffstat_add(diffstat, name_a, name_b);
3290         data->is_interesting = p->status != DIFF_STATUS_UNKNOWN;
3291         if (o->flags.stat_with_summary)
3292                 data->comments = get_compact_summary(p, data->is_renamed);
3293
3294         if (!one || !two) {
3295                 data->is_unmerged = 1;
3296                 return;
3297         }
3298
3299         same_contents = !oidcmp(&one->oid, &two->oid);
3300
3301         if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
3302                 data->is_binary = 1;
3303                 if (same_contents) {
3304                         data->added = 0;
3305                         data->deleted = 0;
3306                 } else {
3307                         data->added = diff_filespec_size(two);
3308                         data->deleted = diff_filespec_size(one);
3309                 }
3310         }
3311
3312         else if (complete_rewrite) {
3313                 diff_populate_filespec(one, 0);
3314                 diff_populate_filespec(two, 0);
3315                 data->deleted = count_lines(one->data, one->size);
3316                 data->added = count_lines(two->data, two->size);
3317         }
3318
3319         else if (!same_contents) {
3320                 /* Crazy xdl interfaces.. */
3321                 xpparam_t xpp;
3322                 xdemitconf_t xecfg;
3323
3324                 if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
3325                         die("unable to read files to diff");
3326
3327                 memset(&xpp, 0, sizeof(xpp));
3328                 memset(&xecfg, 0, sizeof(xecfg));
3329                 xpp.flags = o->xdl_opts;
3330                 xpp.anchors = o->anchors;
3331                 xpp.anchors_nr = o->anchors_nr;
3332                 xecfg.ctxlen = o->context;
3333                 xecfg.interhunkctxlen = o->interhunkcontext;
3334                 if (xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
3335                                   &xpp, &xecfg))
3336                         die("unable to generate diffstat for %s", one->path);
3337         }
3338
3339         diff_free_filespec_data(one);
3340         diff_free_filespec_data(two);
3341 }
3342
3343 static void builtin_checkdiff(const char *name_a, const char *name_b,
3344                               const char *attr_path,
3345                               struct diff_filespec *one,
3346                               struct diff_filespec *two,
3347                               struct diff_options *o)
3348 {
3349         mmfile_t mf1, mf2;
3350         struct checkdiff_t data;
3351
3352         if (!two)
3353                 return;
3354
3355         memset(&data, 0, sizeof(data));
3356         data.filename = name_b ? name_b : name_a;
3357         data.lineno = 0;
3358         data.o = o;
3359         data.ws_rule = whitespace_rule(attr_path);
3360         data.conflict_marker_size = ll_merge_marker_size(attr_path);
3361
3362         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
3363                 die("unable to read files to diff");
3364
3365         /*
3366          * All the other codepaths check both sides, but not checking
3367          * the "old" side here is deliberate.  We are checking the newly
3368          * introduced changes, and as long as the "new" side is text, we
3369          * can and should check what it introduces.
3370          */
3371         if (diff_filespec_is_binary(two))
3372                 goto free_and_return;
3373         else {
3374                 /* Crazy xdl interfaces.. */
3375                 xpparam_t xpp;
3376                 xdemitconf_t xecfg;
3377
3378                 memset(&xpp, 0, sizeof(xpp));
3379                 memset(&xecfg, 0, sizeof(xecfg));
3380                 xecfg.ctxlen = 1; /* at least one context line */
3381                 xpp.flags = 0;
3382                 if (xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
3383                                   &xpp, &xecfg))
3384                         die("unable to generate checkdiff for %s", one->path);
3385
3386                 if (data.ws_rule & WS_BLANK_AT_EOF) {
3387                         struct emit_callback ecbdata;
3388                         int blank_at_eof;
3389
3390                         ecbdata.ws_rule = data.ws_rule;
3391                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
3392                         blank_at_eof = ecbdata.blank_at_eof_in_postimage;
3393
3394                         if (blank_at_eof) {
3395                                 static char *err;
3396                                 if (!err)
3397                                         err = whitespace_error_string(WS_BLANK_AT_EOF);
3398                                 fprintf(o->file, "%s:%d: %s.\n",
3399                                         data.filename, blank_at_eof, err);
3400                                 data.status = 1; /* report errors */
3401                         }
3402                 }
3403         }
3404  free_and_return:
3405         diff_free_filespec_data(one);
3406         diff_free_filespec_data(two);
3407         if (data.status)
3408                 o->flags.check_failed = 1;
3409 }
3410
3411 struct diff_filespec *alloc_filespec(const char *path)
3412 {
3413         struct diff_filespec *spec;
3414
3415         FLEXPTR_ALLOC_STR(spec, path, path);
3416         spec->count = 1;
3417         spec->is_binary = -1;
3418         return spec;
3419 }
3420
3421 void free_filespec(struct diff_filespec *spec)
3422 {
3423         if (!--spec->count) {
3424                 diff_free_filespec_data(spec);
3425                 free(spec);
3426         }
3427 }
3428
3429 void fill_filespec(struct diff_filespec *spec, const struct object_id *oid,
3430                    int oid_valid, unsigned short mode)
3431 {
3432         if (mode) {
3433                 spec->mode = canon_mode(mode);
3434                 oidcpy(&spec->oid, oid);
3435                 spec->oid_valid = oid_valid;
3436         }
3437 }
3438
3439 /*
3440  * Given a name and sha1 pair, if the index tells us the file in
3441  * the work tree has that object contents, return true, so that
3442  * prepare_temp_file() does not have to inflate and extract.
3443  */
3444 static int reuse_worktree_file(const char *name, const struct object_id *oid, int want_file)
3445 {
3446         const struct cache_entry *ce;
3447         struct stat st;
3448         int pos, len;
3449
3450         /*
3451          * We do not read the cache ourselves here, because the
3452          * benchmark with my previous version that always reads cache
3453          * shows that it makes things worse for diff-tree comparing
3454          * two linux-2.6 kernel trees in an already checked out work
3455          * tree.  This is because most diff-tree comparisons deal with
3456          * only a small number of files, while reading the cache is
3457          * expensive for a large project, and its cost outweighs the
3458          * savings we get by not inflating the object to a temporary
3459          * file.  Practically, this code only helps when we are used
3460          * by diff-cache --cached, which does read the cache before
3461          * calling us.
3462          */
3463         if (!active_cache)
3464                 return 0;
3465
3466         /* We want to avoid the working directory if our caller
3467          * doesn't need the data in a normal file, this system
3468          * is rather slow with its stat/open/mmap/close syscalls,
3469          * and the object is contained in a pack file.  The pack
3470          * is probably already open and will be faster to obtain
3471          * the data through than the working directory.  Loose
3472          * objects however would tend to be slower as they need
3473          * to be individually opened and inflated.
3474          */
3475         if (!FAST_WORKING_DIRECTORY && !want_file && has_object_pack(oid))
3476                 return 0;
3477
3478         /*
3479          * Similarly, if we'd have to convert the file contents anyway, that
3480          * makes the optimization not worthwhile.
3481          */
3482         if (!want_file && would_convert_to_git(&the_index, name))
3483                 return 0;
3484
3485         len = strlen(name);
3486         pos = cache_name_pos(name, len);
3487         if (pos < 0)
3488                 return 0;
3489         ce = active_cache[pos];
3490
3491         /*
3492          * This is not the sha1 we are looking for, or
3493          * unreusable because it is not a regular file.
3494          */
3495         if (oidcmp(oid, &ce->oid) || !S_ISREG(ce->ce_mode))
3496                 return 0;
3497
3498         /*
3499          * If ce is marked as "assume unchanged", there is no
3500          * guarantee that work tree matches what we are looking for.
3501          */
3502         if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
3503                 return 0;
3504
3505         /*
3506          * If ce matches the file in the work tree, we can reuse it.
3507          */
3508         if (ce_uptodate(ce) ||
3509             (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
3510                 return 1;
3511
3512         return 0;
3513 }
3514
3515 static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
3516 {
3517         struct strbuf buf = STRBUF_INIT;
3518         char *dirty = "";
3519
3520         /* Are we looking at the work tree? */
3521         if (s->dirty_submodule)
3522                 dirty = "-dirty";
3523
3524         strbuf_addf(&buf, "Subproject commit %s%s\n",
3525                     oid_to_hex(&s->oid), dirty);
3526         s->size = buf.len;
3527         if (size_only) {
3528                 s->data = NULL;
3529                 strbuf_release(&buf);
3530         } else {
3531                 s->data = strbuf_detach(&buf, NULL);
3532                 s->should_free = 1;
3533         }
3534         return 0;
3535 }
3536
3537 /*
3538  * While doing rename detection and pickaxe operation, we may need to
3539  * grab the data for the blob (or file) for our own in-core comparison.
3540  * diff_filespec has data and size fields for this purpose.
3541  */
3542 int diff_populate_filespec(struct diff_filespec *s, unsigned int flags)
3543 {
3544         int size_only = flags & CHECK_SIZE_ONLY;
3545         int err = 0;
3546         int conv_flags = global_conv_flags_eol;
3547         /*
3548          * demote FAIL to WARN to allow inspecting the situation
3549          * instead of refusing.
3550          */
3551         if (conv_flags & CONV_EOL_RNDTRP_DIE)
3552                 conv_flags = CONV_EOL_RNDTRP_WARN;
3553
3554         if (!DIFF_FILE_VALID(s))
3555                 die("internal error: asking to populate invalid file.");
3556         if (S_ISDIR(s->mode))
3557                 return -1;
3558
3559         if (s->data)
3560                 return 0;
3561
3562         if (size_only && 0 < s->size)
3563                 return 0;
3564
3565         if (S_ISGITLINK(s->mode))
3566                 return diff_populate_gitlink(s, size_only);
3567
3568         if (!s->oid_valid ||
3569             reuse_worktree_file(s->path, &s->oid, 0)) {
3570                 struct strbuf buf = STRBUF_INIT;
3571                 struct stat st;
3572                 int fd;
3573
3574                 if (lstat(s->path, &st) < 0) {
3575                 err_empty:
3576                         err = -1;
3577                 empty:
3578                         s->data = (char *)"";
3579                         s->size = 0;
3580                         return err;
3581                 }
3582                 s->size = xsize_t(st.st_size);
3583                 if (!s->size)
3584                         goto empty;
3585                 if (S_ISLNK(st.st_mode)) {
3586                         struct strbuf sb = STRBUF_INIT;
3587
3588                         if (strbuf_readlink(&sb, s->path, s->size))
3589                                 goto err_empty;
3590                         s->size = sb.len;
3591                         s->data = strbuf_detach(&sb, NULL);
3592                         s->should_free = 1;
3593                         return 0;
3594                 }
3595
3596                 /*
3597                  * Even if the caller would be happy with getting
3598                  * only the size, we cannot return early at this
3599                  * point if the path requires us to run the content
3600                  * conversion.
3601                  */
3602                 if (size_only && !would_convert_to_git(&the_index, s->path))
3603                         return 0;
3604
3605                 /*
3606                  * Note: this check uses xsize_t(st.st_size) that may
3607                  * not be the true size of the blob after it goes
3608                  * through convert_to_git().  This may not strictly be
3609                  * correct, but the whole point of big_file_threshold
3610                  * and is_binary check being that we want to avoid
3611                  * opening the file and inspecting the contents, this
3612                  * is probably fine.
3613                  */
3614                 if ((flags & CHECK_BINARY) &&
3615                     s->size > big_file_threshold && s->is_binary == -1) {
3616                         s->is_binary = 1;
3617                         return 0;
3618                 }
3619                 fd = open(s->path, O_RDONLY);
3620                 if (fd < 0)
3621                         goto err_empty;
3622                 s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
3623                 close(fd);
3624                 s->should_munmap = 1;
3625
3626                 /*
3627                  * Convert from working tree format to canonical git format
3628                  */
3629                 if (convert_to_git(&the_index, s->path, s->data, s->size, &buf, conv_flags)) {
3630                         size_t size = 0;
3631                         munmap(s->data, s->size);
3632                         s->should_munmap = 0;
3633                         s->data = strbuf_detach(&buf, &size);
3634                         s->size = size;
3635                         s->should_free = 1;
3636                 }
3637         }
3638         else {
3639                 enum object_type type;
3640                 if (size_only || (flags & CHECK_BINARY)) {
3641                         type = oid_object_info(the_repository, &s->oid,
3642                                                &s->size);
3643                         if (type < 0)
3644                                 die("unable to read %s",
3645                                     oid_to_hex(&s->oid));
3646                         if (size_only)
3647                                 return 0;
3648                         if (s->size > big_file_threshold && s->is_binary == -1) {
3649                                 s->is_binary = 1;
3650                                 return 0;
3651                         }
3652                 }
3653                 s->data = read_object_file(&s->oid, &type, &s->size);
3654                 if (!s->data)
3655                         die("unable to read %s", oid_to_hex(&s->oid));
3656                 s->should_free = 1;
3657         }
3658         return 0;
3659 }
3660
3661 void diff_free_filespec_blob(struct diff_filespec *s)
3662 {
3663         if (s->should_free)
3664                 free(s->data);
3665         else if (s->should_munmap)
3666                 munmap(s->data, s->size);
3667
3668         if (s->should_free || s->should_munmap) {
3669                 s->should_free = s->should_munmap = 0;
3670                 s->data = NULL;
3671         }
3672 }
3673
3674 void diff_free_filespec_data(struct diff_filespec *s)
3675 {
3676         diff_free_filespec_blob(s);
3677         FREE_AND_NULL(s->cnt_data);
3678 }
3679
3680 static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
3681                            void *blob,
3682                            unsigned long size,
3683                            const struct object_id *oid,
3684                            int mode)
3685 {
3686         struct strbuf buf = STRBUF_INIT;
3687         struct strbuf tempfile = STRBUF_INIT;
3688         char *path_dup = xstrdup(path);
3689         const char *base = basename(path_dup);
3690
3691         /* Generate "XXXXXX_basename.ext" */
3692         strbuf_addstr(&tempfile, "XXXXXX_");
3693         strbuf_addstr(&tempfile, base);
3694
3695         temp->tempfile = mks_tempfile_ts(tempfile.buf, strlen(base) + 1);
3696         if (!temp->tempfile)
3697                 die_errno("unable to create temp-file");
3698         if (convert_to_working_tree(path,
3699                         (const char *)blob, (size_t)size, &buf)) {
3700                 blob = buf.buf;
3701                 size = buf.len;
3702         }
3703         if (write_in_full(temp->tempfile->fd, blob, size) < 0 ||
3704             close_tempfile_gently(temp->tempfile))
3705                 die_errno("unable to write temp-file");
3706         temp->name = get_tempfile_path(temp->tempfile);
3707         oid_to_hex_r(temp->hex, oid);
3708         xsnprintf(temp->mode, sizeof(temp->mode), "%06o", mode);
3709         strbuf_release(&buf);
3710         strbuf_release(&tempfile);
3711         free(path_dup);
3712 }
3713
3714 static struct diff_tempfile *prepare_temp_file(const char *name,
3715                 struct diff_filespec *one)
3716 {
3717         struct diff_tempfile *temp = claim_diff_tempfile();
3718
3719         if (!DIFF_FILE_VALID(one)) {
3720         not_a_valid_file:
3721                 /* A '-' entry produces this for file-2, and
3722                  * a '+' entry produces this for file-1.
3723                  */
3724                 temp->name = "/dev/null";
3725                 xsnprintf(temp->hex, sizeof(temp->hex), ".");
3726                 xsnprintf(temp->mode, sizeof(temp->mode), ".");
3727                 return temp;
3728         }
3729
3730         if (!S_ISGITLINK(one->mode) &&
3731             (!one->oid_valid ||
3732              reuse_worktree_file(name, &one->oid, 1))) {
3733                 struct stat st;
3734                 if (lstat(name, &st) < 0) {
3735                         if (errno == ENOENT)
3736                                 goto not_a_valid_file;
3737                         die_errno("stat(%s)", name);
3738                 }
3739                 if (S_ISLNK(st.st_mode)) {
3740                         struct strbuf sb = STRBUF_INIT;
3741                         if (strbuf_readlink(&sb, name, st.st_size) < 0)
3742                                 die_errno("readlink(%s)", name);
3743                         prep_temp_blob(name, temp, sb.buf, sb.len,
3744                                        (one->oid_valid ?
3745                                         &one->oid : &null_oid),
3746                                        (one->oid_valid ?
3747                                         one->mode : S_IFLNK));
3748                         strbuf_release(&sb);
3749                 }
3750                 else {
3751                         /* we can borrow from the file in the work tree */
3752                         temp->name = name;
3753                         if (!one->oid_valid)
3754                                 oid_to_hex_r(temp->hex, &null_oid);
3755                         else
3756                                 oid_to_hex_r(temp->hex, &one->oid);
3757                         /* Even though we may sometimes borrow the
3758                          * contents from the work tree, we always want
3759                          * one->mode.  mode is trustworthy even when
3760                          * !(one->oid_valid), as long as
3761                          * DIFF_FILE_VALID(one).
3762                          */
3763                         xsnprintf(temp->mode, sizeof(temp->mode), "%06o", one->mode);
3764                 }
3765                 return temp;
3766         }
3767         else {
3768                 if (diff_populate_filespec(one, 0))
3769                         die("cannot read data blob for %s", one->path);
3770                 prep_temp_blob(name, temp, one->data, one->size,
3771                                &one->oid, one->mode);
3772         }
3773         return temp;
3774 }
3775
3776 static void add_external_diff_name(struct argv_array *argv,
3777                                    const char *name,
3778                                    struct diff_filespec *df)
3779 {
3780         struct diff_tempfile *temp = prepare_temp_file(name, df);
3781         argv_array_push(argv, temp->name);
3782         argv_array_push(argv, temp->hex);
3783         argv_array_push(argv, temp->mode);
3784 }
3785
3786 /* An external diff command takes:
3787  *
3788  * diff-cmd name infile1 infile1-sha1 infile1-mode \
3789  *               infile2 infile2-sha1 infile2-mode [ rename-to ]
3790  *
3791  */
3792 static void run_external_diff(const char *pgm,
3793                               const char *name,
3794                               const char *other,
3795                               struct diff_filespec *one,
3796                               struct diff_filespec *two,
3797                               const char *xfrm_msg,
3798                               int complete_rewrite,
3799                               struct diff_options *o)
3800 {
3801         struct argv_array argv = ARGV_ARRAY_INIT;
3802         struct argv_array env = ARGV_ARRAY_INIT;
3803         struct diff_queue_struct *q = &diff_queued_diff;
3804
3805         argv_array_push(&argv, pgm);
3806         argv_array_push(&argv, name);
3807
3808         if (one && two) {
3809                 add_external_diff_name(&argv, name, one);
3810                 if (!other)
3811                         add_external_diff_name(&argv, name, two);
3812                 else {
3813                         add_external_diff_name(&argv, other, two);
3814                         argv_array_push(&argv, other);
3815                         argv_array_push(&argv, xfrm_msg);
3816                 }
3817         }
3818
3819         argv_array_pushf(&env, "GIT_DIFF_PATH_COUNTER=%d", ++o->diff_path_counter);
3820         argv_array_pushf(&env, "GIT_DIFF_PATH_TOTAL=%d", q->nr);
3821
3822         if (run_command_v_opt_cd_env(argv.argv, RUN_USING_SHELL, NULL, env.argv))
3823                 die(_("external diff died, stopping at %s"), name);
3824
3825         remove_tempfile();
3826         argv_array_clear(&argv);
3827         argv_array_clear(&env);
3828 }
3829
3830 static int similarity_index(struct diff_filepair *p)
3831 {
3832         return p->score * 100 / MAX_SCORE;
3833 }
3834
3835 static const char *diff_abbrev_oid(const struct object_id *oid, int abbrev)
3836 {
3837         if (startup_info->have_repository)
3838                 return find_unique_abbrev(oid, abbrev);
3839         else {
3840                 char *hex = oid_to_hex(oid);
3841                 if (abbrev < 0)
3842                         abbrev = FALLBACK_DEFAULT_ABBREV;
3843                 if (abbrev > GIT_SHA1_HEXSZ)
3844                         BUG("oid abbreviation out of range: %d", abbrev);
3845                 if (abbrev)
3846                         hex[abbrev] = '\0';
3847                 return hex;
3848         }
3849 }
3850
3851 static void fill_metainfo(struct strbuf *msg,
3852                           const char *name,
3853                           const char *other,
3854                           struct diff_filespec *one,
3855                           struct diff_filespec *two,
3856                           struct diff_options *o,
3857                           struct diff_filepair *p,
3858                           int *must_show_header,
3859                           int use_color)
3860 {
3861         const char *set = diff_get_color(use_color, DIFF_METAINFO);
3862         const char *reset = diff_get_color(use_color, DIFF_RESET);
3863         const char *line_prefix = diff_line_prefix(o);
3864
3865         *must_show_header = 1;
3866         strbuf_init(msg, PATH_MAX * 2 + 300);
3867         switch (p->status) {
3868         case DIFF_STATUS_COPIED:
3869                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
3870                             line_prefix, set, similarity_index(p));
3871                 strbuf_addf(msg, "%s\n%s%scopy from ",
3872                             reset,  line_prefix, set);
3873                 quote_c_style(name, msg, NULL, 0);
3874                 strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
3875                 quote_c_style(other, msg, NULL, 0);
3876                 strbuf_addf(msg, "%s\n", reset);
3877                 break;
3878         case DIFF_STATUS_RENAMED:
3879                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
3880                             line_prefix, set, similarity_index(p));
3881                 strbuf_addf(msg, "%s\n%s%srename from ",
3882                             reset, line_prefix, set);
3883                 quote_c_style(name, msg, NULL, 0);
3884                 strbuf_addf(msg, "%s\n%s%srename to ",
3885                             reset, line_prefix, set);
3886                 quote_c_style(other, msg, NULL, 0);
3887                 strbuf_addf(msg, "%s\n", reset);
3888                 break;
3889         case DIFF_STATUS_MODIFIED:
3890                 if (p->score) {
3891                         strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
3892                                     line_prefix,
3893                                     set, similarity_index(p), reset);
3894                         break;
3895                 }
3896                 /* fallthru */
3897         default:
3898                 *must_show_header = 0;
3899         }
3900         if (one && two && oidcmp(&one->oid, &two->oid)) {
3901                 const unsigned hexsz = the_hash_algo->hexsz;
3902                 int abbrev = o->flags.full_index ? hexsz : DEFAULT_ABBREV;
3903
3904                 if (o->flags.binary) {
3905                         mmfile_t mf;
3906                         if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
3907                             (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
3908                                 abbrev = hexsz;
3909                 }
3910                 strbuf_addf(msg, "%s%sindex %s..%s", line_prefix, set,
3911                             diff_abbrev_oid(&one->oid, abbrev),
3912                             diff_abbrev_oid(&two->oid, abbrev));
3913                 if (one->mode == two->mode)
3914                         strbuf_addf(msg, " %06o", one->mode);
3915                 strbuf_addf(msg, "%s\n", reset);
3916         }
3917 }
3918
3919 static void run_diff_cmd(const char *pgm,
3920                          const char *name,
3921                          const char *other,
3922                          const char *attr_path,
3923                          struct diff_filespec *one,
3924                          struct diff_filespec *two,
3925                          struct strbuf *msg,
3926                          struct diff_options *o,
3927                          struct diff_filepair *p)
3928 {
3929         const char *xfrm_msg = NULL;
3930         int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
3931         int must_show_header = 0;
3932
3933
3934         if (o->flags.allow_external) {
3935                 struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
3936                 if (drv && drv->external)
3937                         pgm = drv->external;
3938         }
3939
3940         if (msg) {
3941                 /*
3942                  * don't use colors when the header is intended for an
3943                  * external diff driver
3944                  */
3945                 fill_metainfo(msg, name, other, one, two, o, p,
3946                               &must_show_header,
3947                               want_color(o->use_color) && !pgm);
3948                 xfrm_msg = msg->len ? msg->buf : NULL;
3949         }
3950
3951         if (pgm) {
3952                 run_external_diff(pgm, name, other, one, two, xfrm_msg,
3953                                   complete_rewrite, o);
3954                 return;
3955         }
3956         if (one && two)
3957                 builtin_diff(name, other ? other : name,
3958                              one, two, xfrm_msg, must_show_header,
3959                              o, complete_rewrite);
3960         else
3961                 fprintf(o->file, "* Unmerged path %s\n", name);
3962 }
3963
3964 static void diff_fill_oid_info(struct diff_filespec *one)
3965 {
3966         if (DIFF_FILE_VALID(one)) {
3967                 if (!one->oid_valid) {
3968                         struct stat st;
3969                         if (one->is_stdin) {
3970                                 oidclr(&one->oid);
3971                                 return;
3972                         }
3973                         if (lstat(one->path, &st) < 0)
3974                                 die_errno("stat '%s'", one->path);
3975                         if (index_path(&one->oid, one->path, &st, 0))
3976                                 die("cannot hash %s", one->path);
3977                 }
3978         }
3979         else
3980                 oidclr(&one->oid);
3981 }
3982
3983 static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
3984 {
3985         /* Strip the prefix but do not molest /dev/null and absolute paths */
3986         if (*namep && **namep != '/') {
3987                 *namep += prefix_length;
3988                 if (**namep == '/')
3989                         ++*namep;
3990         }
3991         if (*otherp && **otherp != '/') {
3992                 *otherp += prefix_length;
3993                 if (**otherp == '/')
3994                         ++*otherp;
3995         }
3996 }
3997
3998 static void run_diff(struct diff_filepair *p, struct diff_options *o)
3999 {
4000         const char *pgm = external_diff();
4001         struct strbuf msg;
4002         struct diff_filespec *one = p->one;
4003         struct diff_filespec *two = p->two;
4004         const char *name;
4005         const char *other;
4006         const char *attr_path;
4007
4008         name  = one->path;
4009         other = (strcmp(name, two->path) ? two->path : NULL);
4010         attr_path = name;
4011         if (o->prefix_length)
4012                 strip_prefix(o->prefix_length, &name, &other);
4013
4014         if (!o->flags.allow_external)
4015                 pgm = NULL;
4016
4017         if (DIFF_PAIR_UNMERGED(p)) {
4018                 run_diff_cmd(pgm, name, NULL, attr_path,
4019                              NULL, NULL, NULL, o, p);
4020                 return;
4021         }
4022
4023         diff_fill_oid_info(one);
4024         diff_fill_oid_info(two);
4025
4026         if (!pgm &&
4027             DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
4028             (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
4029                 /*
4030                  * a filepair that changes between file and symlink
4031                  * needs to be split into deletion and creation.
4032                  */
4033                 struct diff_filespec *null = alloc_filespec(two->path);
4034                 run_diff_cmd(NULL, name, other, attr_path,
4035                              one, null, &msg, o, p);
4036                 free(null);
4037                 strbuf_release(&msg);
4038
4039                 null = alloc_filespec(one->path);
4040                 run_diff_cmd(NULL, name, other, attr_path,
4041                              null, two, &msg, o, p);
4042                 free(null);
4043         }
4044         else
4045                 run_diff_cmd(pgm, name, other, attr_path,
4046                              one, two, &msg, o, p);
4047
4048         strbuf_release(&msg);
4049 }
4050
4051 static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
4052                          struct diffstat_t *diffstat)
4053 {
4054         const char *name;
4055         const char *other;
4056
4057         if (DIFF_PAIR_UNMERGED(p)) {
4058                 /* unmerged */
4059                 builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, p);
4060                 return;
4061         }
4062
4063         name = p->one->path;
4064         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
4065
4066         if (o->prefix_length)
4067                 strip_prefix(o->prefix_length, &name, &other);
4068
4069         diff_fill_oid_info(p->one);
4070         diff_fill_oid_info(p->two);
4071
4072         builtin_diffstat(name, other, p->one, p->two, diffstat, o, p);
4073 }
4074
4075 static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
4076 {
4077         const char *name;
4078         const char *other;
4079         const char *attr_path;
4080
4081         if (DIFF_PAIR_UNMERGED(p)) {
4082                 /* unmerged */
4083                 return;
4084         }
4085
4086         name = p->one->path;
4087         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
4088         attr_path = other ? other : name;
4089
4090         if (o->prefix_length)
4091                 strip_prefix(o->prefix_length, &name, &other);
4092
4093         diff_fill_oid_info(p->one);
4094         diff_fill_oid_info(p->two);
4095
4096         builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
4097 }
4098
4099 void diff_setup(struct diff_options *options)
4100 {
4101         memcpy(options, &default_diff_options, sizeof(*options));
4102
4103         options->file = stdout;
4104
4105         options->abbrev = DEFAULT_ABBREV;
4106         options->line_termination = '\n';
4107         options->break_opt = -1;
4108         options->rename_limit = -1;
4109         options->dirstat_permille = diff_dirstat_permille_default;
4110         options->context = diff_context_default;
4111         options->interhunkcontext = diff_interhunk_context_default;
4112         options->ws_error_highlight = ws_error_highlight_default;
4113         options->flags.rename_empty = 1;
4114         options->objfind = NULL;
4115
4116         /* pathchange left =NULL by default */
4117         options->change = diff_change;
4118         options->add_remove = diff_addremove;
4119         options->use_color = diff_use_color_default;
4120         options->detect_rename = diff_detect_rename_default;
4121         options->xdl_opts |= diff_algorithm;
4122         if (diff_indent_heuristic)
4123                 DIFF_XDL_SET(options, INDENT_HEURISTIC);
4124
4125         options->orderfile = diff_order_file_cfg;
4126
4127         if (diff_no_prefix) {
4128                 options->a_prefix = options->b_prefix = "";
4129         } else if (!diff_mnemonic_prefix) {
4130                 options->a_prefix = "a/";
4131                 options->b_prefix = "b/";
4132         }
4133
4134         options->color_moved = diff_color_moved_default;
4135 }
4136
4137 void diff_setup_done(struct diff_options *options)
4138 {
4139         unsigned check_mask = DIFF_FORMAT_NAME |
4140                               DIFF_FORMAT_NAME_STATUS |
4141                               DIFF_FORMAT_CHECKDIFF |
4142                               DIFF_FORMAT_NO_OUTPUT;
4143         /*
4144          * This must be signed because we're comparing against a potentially
4145          * negative value.
4146          */
4147         const int hexsz = the_hash_algo->hexsz;
4148
4149         if (options->set_default)
4150                 options->set_default(options);
4151
4152         if (HAS_MULTI_BITS(options->output_format & check_mask))
4153                 die(_("--name-only, --name-status, --check and -s are mutually exclusive"));
4154
4155         if (HAS_MULTI_BITS(options->pickaxe_opts & DIFF_PICKAXE_KINDS_MASK))
4156                 die(_("-G, -S and --find-object are mutually exclusive"));
4157
4158         /*
4159          * Most of the time we can say "there are changes"
4160          * only by checking if there are changed paths, but
4161          * --ignore-whitespace* options force us to look
4162          * inside contents.
4163          */
4164
4165         if ((options->xdl_opts & XDF_WHITESPACE_FLAGS))
4166                 options->flags.diff_from_contents = 1;
4167         else
4168                 options->flags.diff_from_contents = 0;
4169
4170         if (options->flags.find_copies_harder)
4171                 options->detect_rename = DIFF_DETECT_COPY;
4172
4173         if (!options->flags.relative_name)
4174                 options->prefix = NULL;
4175         if (options->prefix)
4176                 options->prefix_length = strlen(options->prefix);
4177         else
4178                 options->prefix_length = 0;
4179
4180         if (options->output_format & (DIFF_FORMAT_NAME |
4181                                       DIFF_FORMAT_NAME_STATUS |
4182                                       DIFF_FORMAT_CHECKDIFF |
4183                                       DIFF_FORMAT_NO_OUTPUT))
4184                 options->output_format &= ~(DIFF_FORMAT_RAW |
4185                                             DIFF_FORMAT_NUMSTAT |
4186                                             DIFF_FORMAT_DIFFSTAT |
4187                                             DIFF_FORMAT_SHORTSTAT |
4188                                             DIFF_FORMAT_DIRSTAT |
4189                                             DIFF_FORMAT_SUMMARY |
4190                                             DIFF_FORMAT_PATCH);
4191
4192         /*
4193          * These cases always need recursive; we do not drop caller-supplied
4194          * recursive bits for other formats here.
4195          */
4196         if (options->output_format & (DIFF_FORMAT_PATCH |
4197                                       DIFF_FORMAT_NUMSTAT |
4198                                       DIFF_FORMAT_DIFFSTAT |
4199                                       DIFF_FORMAT_SHORTSTAT |
4200                                       DIFF_FORMAT_DIRSTAT |
4201                                       DIFF_FORMAT_SUMMARY |
4202                                       DIFF_FORMAT_CHECKDIFF))
4203                 options->flags.recursive = 1;
4204         /*
4205          * Also pickaxe would not work very well if you do not say recursive
4206          */
4207         if (options->pickaxe_opts & DIFF_PICKAXE_KINDS_MASK)
4208                 options->flags.recursive = 1;
4209         /*
4210          * When patches are generated, submodules diffed against the work tree
4211          * must be checked for dirtiness too so it can be shown in the output
4212          */
4213         if (options->output_format & DIFF_FORMAT_PATCH)
4214                 options->flags.dirty_submodules = 1;
4215
4216         if (options->detect_rename && options->rename_limit < 0)
4217                 options->rename_limit = diff_rename_limit_default;
4218         if (options->setup & DIFF_SETUP_USE_CACHE) {
4219                 if (!active_cache)
4220                         /* read-cache does not die even when it fails
4221                          * so it is safe for us to do this here.  Also
4222                          * it does not smudge active_cache or active_nr
4223                          * when it fails, so we do not have to worry about
4224                          * cleaning it up ourselves either.
4225                          */
4226                         read_cache();
4227         }
4228         if (hexsz < options->abbrev)
4229                 options->abbrev = hexsz; /* full */
4230
4231         /*
4232          * It does not make sense to show the first hit we happened
4233          * to have found.  It does not make sense not to return with
4234          * exit code in such a case either.
4235          */
4236         if (options->flags.quick) {
4237                 options->output_format = DIFF_FORMAT_NO_OUTPUT;
4238                 options->flags.exit_with_status = 1;
4239         }
4240
4241         options->diff_path_counter = 0;
4242
4243         if (options->flags.follow_renames && options->pathspec.nr != 1)
4244                 die(_("--follow requires exactly one pathspec"));
4245
4246         if (!options->use_color || external_diff())
4247                 options->color_moved = 0;
4248 }
4249
4250 static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
4251 {
4252         char c, *eq;
4253         int len;
4254
4255         if (*arg != '-')
4256                 return 0;
4257         c = *++arg;
4258         if (!c)
4259                 return 0;
4260         if (c == arg_short) {
4261                 c = *++arg;
4262                 if (!c)
4263                         return 1;
4264                 if (val && isdigit(c)) {
4265                         char *end;
4266                         int n = strtoul(arg, &end, 10);
4267                         if (*end)
4268                                 return 0;
4269                         *val = n;
4270                         return 1;
4271                 }
4272                 return 0;
4273         }
4274         if (c != '-')
4275                 return 0;
4276         arg++;
4277         eq = strchrnul(arg, '=');
4278         len = eq - arg;
4279         if (!len || strncmp(arg, arg_long, len))
4280                 return 0;
4281         if (*eq) {
4282                 int n;
4283                 char *end;
4284                 if (!isdigit(*++eq))
4285                         return 0;
4286                 n = strtoul(eq, &end, 10);
4287                 if (*end)
4288                         return 0;
4289                 *val = n;
4290         }
4291         return 1;
4292 }
4293
4294 static int diff_scoreopt_parse(const char *opt);
4295
4296 static inline int short_opt(char opt, const char **argv,
4297                             const char **optarg)
4298 {
4299         const char *arg = argv[0];
4300         if (arg[0] != '-' || arg[1] != opt)
4301                 return 0;
4302         if (arg[2] != '\0') {
4303                 *optarg = arg + 2;
4304                 return 1;
4305         }
4306         if (!argv[1])
4307                 die("Option '%c' requires a value", opt);
4308         *optarg = argv[1];
4309         return 2;
4310 }
4311
4312 int parse_long_opt(const char *opt, const char **argv,
4313                    const char **optarg)
4314 {
4315         const char *arg = argv[0];
4316         if (!skip_prefix(arg, "--", &arg))
4317                 return 0;
4318         if (!skip_prefix(arg, opt, &arg))
4319                 return 0;
4320         if (*arg == '=') { /* stuck form: --option=value */
4321                 *optarg = arg + 1;
4322                 return 1;
4323         }
4324         if (*arg != '\0')
4325                 return 0;
4326         /* separate form: --option value */
4327         if (!argv[1])
4328                 die("Option '--%s' requires a value", opt);
4329         *optarg = argv[1];
4330         return 2;
4331 }
4332
4333 static int stat_opt(struct diff_options *options, const char **av)
4334 {
4335         const char *arg = av[0];
4336         char *end;
4337         int width = options->stat_width;
4338         int name_width = options->stat_name_width;
4339         int graph_width = options->stat_graph_width;
4340         int count = options->stat_count;
4341         int argcount = 1;
4342
4343         if (!skip_prefix(arg, "--stat", &arg))
4344                 BUG("stat option does not begin with --stat: %s", arg);
4345         end = (char *)arg;
4346
4347         switch (*arg) {
4348         case '-':
4349                 if (skip_prefix(arg, "-width", &arg)) {
4350                         if (*arg == '=')
4351                                 width = strtoul(arg + 1, &end, 10);
4352                         else if (!*arg && !av[1])
4353                                 die_want_option("--stat-width");
4354                         else if (!*arg) {
4355                                 width = strtoul(av[1], &end, 10);
4356                                 argcount = 2;
4357                         }
4358                 } else if (skip_prefix(arg, "-name-width", &arg)) {
4359                         if (*arg == '=')
4360                                 name_width = strtoul(arg + 1, &end, 10);
4361                         else if (!*arg && !av[1])
4362                                 die_want_option("--stat-name-width");
4363                         else if (!*arg) {
4364                                 name_width = strtoul(av[1], &end, 10);
4365                                 argcount = 2;
4366                         }
4367                 } else if (skip_prefix(arg, "-graph-width", &arg)) {
4368                         if (*arg == '=')
4369                                 graph_width = strtoul(arg + 1, &end, 10);
4370                         else if (!*arg && !av[1])
4371                                 die_want_option("--stat-graph-width");
4372                         else if (!*arg) {
4373                                 graph_width = strtoul(av[1], &end, 10);
4374                                 argcount = 2;
4375                         }
4376                 } else if (skip_prefix(arg, "-count", &arg)) {
4377                         if (*arg == '=')
4378                                 count = strtoul(arg + 1, &end, 10);
4379                         else if (!*arg && !av[1])
4380                                 die_want_option("--stat-count");
4381                         else if (!*arg) {
4382                                 count = strtoul(av[1], &end, 10);
4383                                 argcount = 2;
4384                         }
4385                 }
4386                 break;
4387         case '=':
4388                 width = strtoul(arg+1, &end, 10);
4389                 if (*end == ',')
4390                         name_width = strtoul(end+1, &end, 10);
4391                 if (*end == ',')
4392                         count = strtoul(end+1, &end, 10);
4393         }
4394
4395         /* Important! This checks all the error cases! */
4396         if (*end)
4397                 return 0;
4398         options->output_format |= DIFF_FORMAT_DIFFSTAT;
4399         options->stat_name_width = name_width;
4400         options->stat_graph_width = graph_width;
4401         options->stat_width = width;
4402         options->stat_count = count;
4403         return argcount;
4404 }
4405
4406 static int parse_dirstat_opt(struct diff_options *options, const char *params)
4407 {
4408         struct strbuf errmsg = STRBUF_INIT;
4409         if (parse_dirstat_params(options, params, &errmsg))
4410                 die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
4411                     errmsg.buf);
4412         strbuf_release(&errmsg);
4413         /*
4414          * The caller knows a dirstat-related option is given from the command
4415          * line; allow it to say "return this_function();"
4416          */
4417         options->output_format |= DIFF_FORMAT_DIRSTAT;
4418         return 1;
4419 }
4420
4421 static int parse_submodule_opt(struct diff_options *options, const char *value)
4422 {
4423         if (parse_submodule_params(options, value))
4424                 die(_("Failed to parse --submodule option parameter: '%s'"),
4425                         value);
4426         return 1;
4427 }
4428
4429 static const char diff_status_letters[] = {
4430         DIFF_STATUS_ADDED,
4431         DIFF_STATUS_COPIED,
4432         DIFF_STATUS_DELETED,
4433         DIFF_STATUS_MODIFIED,
4434         DIFF_STATUS_RENAMED,
4435         DIFF_STATUS_TYPE_CHANGED,
4436         DIFF_STATUS_UNKNOWN,
4437         DIFF_STATUS_UNMERGED,
4438         DIFF_STATUS_FILTER_AON,
4439         DIFF_STATUS_FILTER_BROKEN,
4440         '\0',
4441 };
4442
4443 static unsigned int filter_bit['Z' + 1];
4444
4445 static void prepare_filter_bits(void)
4446 {
4447         int i;
4448
4449         if (!filter_bit[DIFF_STATUS_ADDED]) {
4450                 for (i = 0; diff_status_letters[i]; i++)
4451                         filter_bit[(int) diff_status_letters[i]] = (1 << i);
4452         }
4453 }
4454
4455 static unsigned filter_bit_tst(char status, const struct diff_options *opt)
4456 {
4457         return opt->filter & filter_bit[(int) status];
4458 }
4459
4460 static int parse_diff_filter_opt(const char *optarg, struct diff_options *opt)
4461 {
4462         int i, optch;
4463
4464         prepare_filter_bits();
4465
4466         /*
4467          * If there is a negation e.g. 'd' in the input, and we haven't
4468          * initialized the filter field with another --diff-filter, start
4469          * from full set of bits, except for AON.
4470          */
4471         if (!opt->filter) {
4472                 for (i = 0; (optch = optarg[i]) != '\0'; i++) {
4473                         if (optch < 'a' || 'z' < optch)
4474                                 continue;
4475                         opt->filter = (1 << (ARRAY_SIZE(diff_status_letters) - 1)) - 1;
4476                         opt->filter &= ~filter_bit[DIFF_STATUS_FILTER_AON];
4477                         break;
4478                 }
4479         }
4480
4481         for (i = 0; (optch = optarg[i]) != '\0'; i++) {
4482                 unsigned int bit;
4483                 int negate;
4484
4485                 if ('a' <= optch && optch <= 'z') {
4486                         negate = 1;
4487                         optch = toupper(optch);
4488                 } else {
4489                         negate = 0;
4490                 }
4491
4492                 bit = (0 <= optch && optch <= 'Z') ? filter_bit[optch] : 0;
4493                 if (!bit)
4494                         return optarg[i];
4495                 if (negate)
4496                         opt->filter &= ~bit;
4497                 else
4498                         opt->filter |= bit;
4499         }
4500         return 0;
4501 }
4502
4503 static void enable_patch_output(int *fmt) {
4504         *fmt &= ~DIFF_FORMAT_NO_OUTPUT;
4505         *fmt |= DIFF_FORMAT_PATCH;
4506 }
4507
4508 static int parse_ws_error_highlight_opt(struct diff_options *opt, const char *arg)
4509 {
4510         int val = parse_ws_error_highlight(arg);
4511
4512         if (val < 0) {
4513                 error("unknown value after ws-error-highlight=%.*s",
4514                       -1 - val, arg);
4515                 return 0;
4516         }
4517         opt->ws_error_highlight = val;
4518         return 1;
4519 }
4520
4521 static int parse_objfind_opt(struct diff_options *opt, const char *arg)
4522 {
4523         struct object_id oid;
4524
4525         if (get_oid(arg, &oid))
4526                 return error("unable to resolve '%s'", arg);
4527
4528         if (!opt->objfind)
4529                 opt->objfind = xcalloc(1, sizeof(*opt->objfind));
4530
4531         opt->pickaxe_opts |= DIFF_PICKAXE_KIND_OBJFIND;
4532         opt->flags.recursive = 1;
4533         opt->flags.tree_in_recursive = 1;
4534         oidset_insert(opt->objfind, &oid);
4535         return 1;
4536 }
4537
4538 int diff_opt_parse(struct diff_options *options,
4539                    const char **av, int ac, const char *prefix)
4540 {
4541         const char *arg = av[0];
4542         const char *optarg;
4543         int argcount;
4544
4545         if (!prefix)
4546                 prefix = "";
4547
4548         /* Output format options */
4549         if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch")
4550             || opt_arg(arg, 'U', "unified", &options->context))
4551                 enable_patch_output(&options->output_format);
4552         else if (!strcmp(arg, "--raw"))
4553                 options->output_format |= DIFF_FORMAT_RAW;
4554         else if (!strcmp(arg, "--patch-with-raw")) {
4555                 enable_patch_output(&options->output_format);
4556                 options->output_format |= DIFF_FORMAT_RAW;
4557         } else if (!strcmp(arg, "--numstat"))
4558                 options->output_format |= DIFF_FORMAT_NUMSTAT;
4559         else if (!strcmp(arg, "--shortstat"))
4560                 options->output_format |= DIFF_FORMAT_SHORTSTAT;
4561         else if (skip_prefix(arg, "-X", &arg) ||
4562                  skip_to_optional_arg(arg, "--dirstat", &arg))
4563                 return parse_dirstat_opt(options, arg);
4564         else if (!strcmp(arg, "--cumulative"))
4565                 return parse_dirstat_opt(options, "cumulative");
4566         else if (skip_to_optional_arg(arg, "--dirstat-by-file", &arg)) {
4567                 parse_dirstat_opt(options, "files");
4568                 return parse_dirstat_opt(options, arg);
4569         }
4570         else if (!strcmp(arg, "--check"))
4571                 options->output_format |= DIFF_FORMAT_CHECKDIFF;
4572         else if (!strcmp(arg, "--summary"))
4573                 options->output_format |= DIFF_FORMAT_SUMMARY;
4574         else if (!strcmp(arg, "--patch-with-stat")) {
4575                 enable_patch_output(&options->output_format);
4576                 options->output_format |= DIFF_FORMAT_DIFFSTAT;
4577         } else if (!strcmp(arg, "--name-only"))
4578                 options->output_format |= DIFF_FORMAT_NAME;
4579         else if (!strcmp(arg, "--name-status"))
4580                 options->output_format |= DIFF_FORMAT_NAME_STATUS;
4581         else if (!strcmp(arg, "-s") || !strcmp(arg, "--no-patch"))
4582                 options->output_format |= DIFF_FORMAT_NO_OUTPUT;
4583         else if (starts_with(arg, "--stat"))
4584                 /* --stat, --stat-width, --stat-name-width, or --stat-count */
4585                 return stat_opt(options, av);
4586         else if (!strcmp(arg, "--compact-summary")) {
4587                  options->flags.stat_with_summary = 1;
4588                  options->output_format |= DIFF_FORMAT_DIFFSTAT;
4589         } else if (!strcmp(arg, "--no-compact-summary"))
4590                  options->flags.stat_with_summary = 0;
4591
4592         /* renames options */
4593         else if (starts_with(arg, "-B") ||
4594                  skip_to_optional_arg(arg, "--break-rewrites", NULL)) {
4595                 if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
4596                         return error("invalid argument to -B: %s", arg+2);
4597         }
4598         else if (starts_with(arg, "-M") ||
4599                  skip_to_optional_arg(arg, "--find-renames", NULL)) {
4600                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
4601                         return error("invalid argument to -M: %s", arg+2);
4602                 options->detect_rename = DIFF_DETECT_RENAME;
4603         }
4604         else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
4605                 options->irreversible_delete = 1;
4606         }
4607         else if (starts_with(arg, "-C") ||
4608                  skip_to_optional_arg(arg, "--find-copies", NULL)) {
4609                 if (options->detect_rename == DIFF_DETECT_COPY)
4610                         options->flags.find_copies_harder = 1;
4611                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
4612                         return error("invalid argument to -C: %s", arg+2);
4613                 options->detect_rename = DIFF_DETECT_COPY;
4614         }
4615         else if (!strcmp(arg, "--no-renames"))
4616                 options->detect_rename = 0;
4617         else if (!strcmp(arg, "--rename-empty"))
4618                 options->flags.rename_empty = 1;
4619         else if (!strcmp(arg, "--no-rename-empty"))
4620                 options->flags.rename_empty = 0;
4621         else if (skip_to_optional_arg_default(arg, "--relative", &arg, NULL)) {
4622                 options->flags.relative_name = 1;
4623                 if (arg)
4624                         options->prefix = arg;
4625         }
4626
4627         /* xdiff options */
4628         else if (!strcmp(arg, "--minimal"))
4629                 DIFF_XDL_SET(options, NEED_MINIMAL);
4630         else if (!strcmp(arg, "--no-minimal"))
4631                 DIFF_XDL_CLR(options, NEED_MINIMAL);
4632         else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
4633                 DIFF_XDL_SET(options, IGNORE_WHITESPACE);
4634         else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
4635                 DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
4636         else if (!strcmp(arg, "--ignore-space-at-eol"))
4637                 DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
4638         else if (!strcmp(arg, "--ignore-cr-at-eol"))
4639                 DIFF_XDL_SET(options, IGNORE_CR_AT_EOL);
4640         else if (!strcmp(arg, "--ignore-blank-lines"))
4641                 DIFF_XDL_SET(options, IGNORE_BLANK_LINES);
4642         else if (!strcmp(arg, "--indent-heuristic"))
4643                 DIFF_XDL_SET(options, INDENT_HEURISTIC);
4644         else if (!strcmp(arg, "--no-indent-heuristic"))
4645                 DIFF_XDL_CLR(options, INDENT_HEURISTIC);
4646         else if (!strcmp(arg, "--patience")) {
4647                 int i;
4648                 options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
4649                 /*
4650                  * Both --patience and --anchored use PATIENCE_DIFF
4651                  * internally, so remove any anchors previously
4652                  * specified.
4653                  */
4654                 for (i = 0; i < options->anchors_nr; i++)
4655                         free(options->anchors[i]);
4656                 options->anchors_nr = 0;
4657         } else if (!strcmp(arg, "--histogram"))
4658                 options->xdl_opts = DIFF_WITH_ALG(options, HISTOGRAM_DIFF);
4659         else if ((argcount = parse_long_opt("diff-algorithm", av, &optarg))) {
4660                 long value = parse_algorithm_value(optarg);
4661                 if (value < 0)
4662                         return error("option diff-algorithm accepts \"myers\", "
4663                                      "\"minimal\", \"patience\" and \"histogram\"");
4664                 /* clear out previous settings */
4665                 DIFF_XDL_CLR(options, NEED_MINIMAL);
4666                 options->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
4667                 options->xdl_opts |= value;
4668                 return argcount;
4669         } else if (skip_prefix(arg, "--anchored=", &arg)) {
4670                 options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
4671                 ALLOC_GROW(options->anchors, options->anchors_nr + 1,
4672                            options->anchors_alloc);
4673                 options->anchors[options->anchors_nr++] = xstrdup(arg);
4674         }
4675
4676         /* flags options */
4677         else if (!strcmp(arg, "--binary")) {
4678                 enable_patch_output(&options->output_format);
4679                 options->flags.binary = 1;
4680         }
4681         else if (!strcmp(arg, "--full-index"))
4682                 options->flags.full_index = 1;
4683         else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
4684                 options->flags.text = 1;
4685         else if (!strcmp(arg, "-R"))
4686                 options->flags.reverse_diff = 1;
4687         else if (!strcmp(arg, "--find-copies-harder"))
4688                 options->flags.find_copies_harder = 1;
4689         else if (!strcmp(arg, "--follow"))
4690                 options->flags.follow_renames = 1;
4691         else if (!strcmp(arg, "--no-follow")) {
4692                 options->flags.follow_renames = 0;
4693                 options->flags.default_follow_renames = 0;
4694         } else if (skip_to_optional_arg_default(arg, "--color", &arg, "always")) {
4695                 int value = git_config_colorbool(NULL, arg);
4696                 if (value < 0)
4697                         return error("option `color' expects \"always\", \"auto\", or \"never\"");
4698                 options->use_color = value;
4699         }
4700         else if (!strcmp(arg, "--no-color"))
4701                 options->use_color = 0;
4702         else if (!strcmp(arg, "--color-moved")) {
4703                 if (diff_color_moved_default)
4704                         options->color_moved = diff_color_moved_default;
4705                 if (options->color_moved == COLOR_MOVED_NO)
4706                         options->color_moved = COLOR_MOVED_DEFAULT;
4707         } else if (!strcmp(arg, "--no-color-moved"))
4708                 options->color_moved = COLOR_MOVED_NO;
4709         else if (skip_prefix(arg, "--color-moved=", &arg)) {
4710                 int cm = parse_color_moved(arg);
4711                 if (cm < 0)
4712                         die("bad --color-moved argument: %s", arg);
4713                 options->color_moved = cm;
4714         } else if (skip_to_optional_arg_default(arg, "--color-words", &options->word_regex, NULL)) {
4715                 options->use_color = 1;
4716                 options->word_diff = DIFF_WORDS_COLOR;
4717         }
4718         else if (!strcmp(arg, "--word-diff")) {
4719                 if (options->word_diff == DIFF_WORDS_NONE)
4720                         options->word_diff = DIFF_WORDS_PLAIN;
4721         }
4722         else if (skip_prefix(arg, "--word-diff=", &arg)) {
4723                 if (!strcmp(arg, "plain"))
4724                         options->word_diff = DIFF_WORDS_PLAIN;
4725                 else if (!strcmp(arg, "color")) {
4726                         options->use_color = 1;
4727                         options->word_diff = DIFF_WORDS_COLOR;
4728                 }
4729                 else if (!strcmp(arg, "porcelain"))
4730                         options->word_diff = DIFF_WORDS_PORCELAIN;
4731                 else if (!strcmp(arg, "none"))
4732                         options->word_diff = DIFF_WORDS_NONE;
4733                 else
4734                         die("bad --word-diff argument: %s", arg);
4735         }
4736         else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
4737                 if (options->word_diff == DIFF_WORDS_NONE)
4738                         options->word_diff = DIFF_WORDS_PLAIN;
4739                 options->word_regex = optarg;
4740                 return argcount;
4741         }
4742         else if (!strcmp(arg, "--exit-code"))
4743                 options->flags.exit_with_status = 1;
4744         else if (!strcmp(arg, "--quiet"))
4745                 options->flags.quick = 1;
4746         else if (!strcmp(arg, "--ext-diff"))
4747                 options->flags.allow_external = 1;
4748         else if (!strcmp(arg, "--no-ext-diff"))
4749                 options->flags.allow_external = 0;
4750         else if (!strcmp(arg, "--textconv")) {
4751                 options->flags.allow_textconv = 1;
4752                 options->flags.textconv_set_via_cmdline = 1;
4753         } else if (!strcmp(arg, "--no-textconv"))
4754                 options->flags.allow_textconv = 0;
4755         else if (skip_to_optional_arg_default(arg, "--ignore-submodules", &arg, "all")) {
4756                 options->flags.override_submodule_config = 1;
4757                 handle_ignore_submodules_arg(options, arg);
4758         } else if (skip_to_optional_arg_default(arg, "--submodule", &arg, "log"))
4759                 return parse_submodule_opt(options, arg);
4760         else if (skip_prefix(arg, "--ws-error-highlight=", &arg))
4761                 return parse_ws_error_highlight_opt(options, arg);
4762         else if (!strcmp(arg, "--ita-invisible-in-index"))
4763                 options->ita_invisible_in_index = 1;
4764         else if (!strcmp(arg, "--ita-visible-in-index"))
4765                 options->ita_invisible_in_index = 0;
4766
4767         /* misc options */
4768         else if (!strcmp(arg, "-z"))
4769                 options->line_termination = 0;
4770         else if ((argcount = short_opt('l', av, &optarg))) {
4771                 options->rename_limit = strtoul(optarg, NULL, 10);
4772                 return argcount;
4773         }
4774         else if ((argcount = short_opt('S', av, &optarg))) {
4775                 options->pickaxe = optarg;
4776                 options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
4777                 return argcount;
4778         } else if ((argcount = short_opt('G', av, &optarg))) {
4779                 options->pickaxe = optarg;
4780                 options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
4781                 return argcount;
4782         }
4783         else if (!strcmp(arg, "--pickaxe-all"))
4784                 options->pickaxe_opts |= DIFF_PICKAXE_ALL;
4785         else if (!strcmp(arg, "--pickaxe-regex"))
4786                 options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
4787         else if ((argcount = short_opt('O', av, &optarg))) {
4788                 options->orderfile = prefix_filename(prefix, optarg);
4789                 return argcount;
4790         } else if (skip_prefix(arg, "--find-object=", &arg))
4791                 return parse_objfind_opt(options, arg);
4792         else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
4793                 int offending = parse_diff_filter_opt(optarg, options);
4794                 if (offending)
4795                         die("unknown change class '%c' in --diff-filter=%s",
4796                             offending, optarg);
4797                 return argcount;
4798         }
4799         else if (!strcmp(arg, "--no-abbrev"))
4800                 options->abbrev = 0;
4801         else if (!strcmp(arg, "--abbrev"))
4802                 options->abbrev = DEFAULT_ABBREV;
4803         else if (skip_prefix(arg, "--abbrev=", &arg)) {
4804                 options->abbrev = strtoul(arg, NULL, 10);
4805                 if (options->abbrev < MINIMUM_ABBREV)
4806                         options->abbrev = MINIMUM_ABBREV;
4807                 else if (the_hash_algo->hexsz < options->abbrev)
4808                         options->abbrev = the_hash_algo->hexsz;
4809         }
4810         else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
4811                 options->a_prefix = optarg;
4812                 return argcount;
4813         }
4814         else if ((argcount = parse_long_opt("line-prefix", av, &optarg))) {
4815                 options->line_prefix = optarg;
4816                 options->line_prefix_length = strlen(options->line_prefix);
4817                 graph_setup_line_prefix(options);
4818                 return argcount;
4819         }
4820         else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
4821                 options->b_prefix = optarg;
4822                 return argcount;
4823         }
4824         else if (!strcmp(arg, "--no-prefix"))
4825                 options->a_prefix = options->b_prefix = "";
4826         else if (opt_arg(arg, '\0', "inter-hunk-context",
4827                          &options->interhunkcontext))
4828                 ;
4829         else if (!strcmp(arg, "-W"))
4830                 options->flags.funccontext = 1;
4831         else if (!strcmp(arg, "--function-context"))
4832                 options->flags.funccontext = 1;
4833         else if (!strcmp(arg, "--no-function-context"))
4834                 options->flags.funccontext = 0;
4835         else if ((argcount = parse_long_opt("output", av, &optarg))) {
4836                 char *path = prefix_filename(prefix, optarg);
4837                 options->file = xfopen(path, "w");
4838                 options->close_file = 1;
4839                 if (options->use_color != GIT_COLOR_ALWAYS)
4840                         options->use_color = GIT_COLOR_NEVER;
4841                 free(path);
4842                 return argcount;
4843         } else
4844                 return 0;
4845         return 1;
4846 }
4847
4848 int parse_rename_score(const char **cp_p)
4849 {
4850         unsigned long num, scale;
4851         int ch, dot;
4852         const char *cp = *cp_p;
4853
4854         num = 0;
4855         scale = 1;
4856         dot = 0;
4857         for (;;) {
4858                 ch = *cp;
4859                 if ( !dot && ch == '.' ) {
4860                         scale = 1;
4861                         dot = 1;
4862                 } else if ( ch == '%' ) {
4863                         scale = dot ? scale*100 : 100;
4864                         cp++;   /* % is always at the end */
4865                         break;
4866                 } else if ( ch >= '0' && ch <= '9' ) {
4867                         if ( scale < 100000 ) {
4868                                 scale *= 10;
4869                                 num = (num*10) + (ch-'0');
4870                         }
4871                 } else {
4872                         break;
4873                 }
4874                 cp++;
4875         }
4876         *cp_p = cp;
4877
4878         /* user says num divided by scale and we say internally that
4879          * is MAX_SCORE * num / scale.
4880          */
4881         return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
4882 }
4883
4884 static int diff_scoreopt_parse(const char *opt)
4885 {
4886         int opt1, opt2, cmd;
4887
4888         if (*opt++ != '-')
4889                 return -1;
4890         cmd = *opt++;
4891         if (cmd == '-') {
4892                 /* convert the long-form arguments into short-form versions */
4893                 if (skip_prefix(opt, "break-rewrites", &opt)) {
4894                         if (*opt == 0 || *opt++ == '=')
4895                                 cmd = 'B';
4896                 } else if (skip_prefix(opt, "find-copies", &opt)) {
4897                         if (*opt == 0 || *opt++ == '=')
4898                                 cmd = 'C';
4899                 } else if (skip_prefix(opt, "find-renames", &opt)) {
4900                         if (*opt == 0 || *opt++ == '=')
4901                                 cmd = 'M';
4902                 }
4903         }
4904         if (cmd != 'M' && cmd != 'C' && cmd != 'B')
4905                 return -1; /* that is not a -M, -C, or -B option */
4906
4907         opt1 = parse_rename_score(&opt);
4908         if (cmd != 'B')
4909                 opt2 = 0;
4910         else {
4911                 if (*opt == 0)
4912                         opt2 = 0;
4913                 else if (*opt != '/')
4914                         return -1; /* we expect -B80/99 or -B80 */
4915                 else {
4916                         opt++;
4917                         opt2 = parse_rename_score(&opt);
4918                 }
4919         }
4920         if (*opt != 0)
4921                 return -1;
4922         return opt1 | (opt2 << 16);
4923 }
4924
4925 struct diff_queue_struct diff_queued_diff;
4926
4927 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
4928 {
4929         ALLOC_GROW(queue->queue, queue->nr + 1, queue->alloc);
4930         queue->queue[queue->nr++] = dp;
4931 }
4932
4933 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
4934                                  struct diff_filespec *one,
4935                                  struct diff_filespec *two)
4936 {
4937         struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
4938         dp->one = one;
4939         dp->two = two;
4940         if (queue)
4941                 diff_q(queue, dp);
4942         return dp;
4943 }
4944
4945 void diff_free_filepair(struct diff_filepair *p)
4946 {
4947         free_filespec(p->one);
4948         free_filespec(p->two);
4949         free(p);
4950 }
4951
4952 const char *diff_aligned_abbrev(const struct object_id *oid, int len)
4953 {
4954         int abblen;
4955         const char *abbrev;
4956
4957         /* Do we want all 40 hex characters? */
4958         if (len == GIT_SHA1_HEXSZ)
4959                 return oid_to_hex(oid);
4960
4961         /* An abbreviated value is fine, possibly followed by an ellipsis. */
4962         abbrev = diff_abbrev_oid(oid, len);
4963
4964         if (!print_sha1_ellipsis())
4965                 return abbrev;
4966
4967         abblen = strlen(abbrev);
4968
4969         /*
4970          * In well-behaved cases, where the abbreviated result is the
4971          * same as the requested length, append three dots after the
4972          * abbreviation (hence the whole logic is limited to the case
4973          * where abblen < 37); when the actual abbreviated result is a
4974          * bit longer than the requested length, we reduce the number
4975          * of dots so that they match the well-behaved ones.  However,
4976          * if the actual abbreviation is longer than the requested
4977          * length by more than three, we give up on aligning, and add
4978          * three dots anyway, to indicate that the output is not the
4979          * full object name.  Yes, this may be suboptimal, but this
4980          * appears only in "diff --raw --abbrev" output and it is not
4981          * worth the effort to change it now.  Note that this would
4982          * likely to work fine when the automatic sizing of default
4983          * abbreviation length is used--we would be fed -1 in "len" in
4984          * that case, and will end up always appending three-dots, but
4985          * the automatic sizing is supposed to give abblen that ensures
4986          * uniqueness across all objects (statistically speaking).
4987          */
4988         if (abblen < GIT_SHA1_HEXSZ - 3) {
4989                 static char hex[GIT_MAX_HEXSZ + 1];
4990                 if (len < abblen && abblen <= len + 2)
4991                         xsnprintf(hex, sizeof(hex), "%s%.*s", abbrev, len+3-abblen, "..");
4992                 else
4993                         xsnprintf(hex, sizeof(hex), "%s...", abbrev);
4994                 return hex;
4995         }
4996
4997         return oid_to_hex(oid);
4998 }
4999
5000 static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
5001 {
5002         int line_termination = opt->line_termination;
5003         int inter_name_termination = line_termination ? '\t' : '\0';
5004
5005         fprintf(opt->file, "%s", diff_line_prefix(opt));
5006         if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
5007                 fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
5008                         diff_aligned_abbrev(&p->one->oid, opt->abbrev));
5009                 fprintf(opt->file, "%s ",
5010                         diff_aligned_abbrev(&p->two->oid, opt->abbrev));
5011         }
5012         if (p->score) {
5013                 fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
5014                         inter_name_termination);
5015         } else {
5016                 fprintf(opt->file, "%c%c", p->status, inter_name_termination);
5017         }
5018
5019         if (p->status == DIFF_STATUS_COPIED ||
5020             p->status == DIFF_STATUS_RENAMED) {
5021                 const char *name_a, *name_b;
5022                 name_a = p->one->path;
5023                 name_b = p->two->path;
5024                 strip_prefix(opt->prefix_length, &name_a, &name_b);
5025                 write_name_quoted(name_a, opt->file, inter_name_termination);
5026                 write_name_quoted(name_b, opt->file, line_termination);
5027         } else {
5028                 const char *name_a, *name_b;
5029                 name_a = p->one->mode ? p->one->path : p->two->path;
5030                 name_b = NULL;
5031                 strip_prefix(opt->prefix_length, &name_a, &name_b);
5032                 write_name_quoted(name_a, opt->file, line_termination);
5033         }
5034 }
5035
5036 int diff_unmodified_pair(struct diff_filepair *p)
5037 {
5038         /* This function is written stricter than necessary to support
5039          * the currently implemented transformers, but the idea is to
5040          * let transformers to produce diff_filepairs any way they want,
5041          * and filter and clean them up here before producing the output.
5042          */
5043         struct diff_filespec *one = p->one, *two = p->two;
5044
5045         if (DIFF_PAIR_UNMERGED(p))
5046                 return 0; /* unmerged is interesting */
5047
5048         /* deletion, addition, mode or type change
5049          * and rename are all interesting.
5050          */
5051         if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
5052             DIFF_PAIR_MODE_CHANGED(p) ||
5053             strcmp(one->path, two->path))
5054                 return 0;
5055
5056         /* both are valid and point at the same path.  that is, we are
5057          * dealing with a change.
5058          */
5059         if (one->oid_valid && two->oid_valid &&
5060             !oidcmp(&one->oid, &two->oid) &&
5061             !one->dirty_submodule && !two->dirty_submodule)
5062                 return 1; /* no change */
5063         if (!one->oid_valid && !two->oid_valid)
5064                 return 1; /* both look at the same file on the filesystem. */
5065         return 0;
5066 }
5067
5068 static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
5069 {
5070         if (diff_unmodified_pair(p))
5071                 return;
5072
5073         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5074             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5075                 return; /* no tree diffs in patch format */
5076
5077         run_diff(p, o);
5078 }
5079
5080 static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
5081                             struct diffstat_t *diffstat)
5082 {
5083         if (diff_unmodified_pair(p))
5084                 return;
5085
5086         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5087             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5088                 return; /* no useful stat for tree diffs */
5089
5090         run_diffstat(p, o, diffstat);
5091 }
5092
5093 static void diff_flush_checkdiff(struct diff_filepair *p,
5094                 struct diff_options *o)
5095 {
5096         if (diff_unmodified_pair(p))
5097                 return;
5098
5099         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5100             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5101                 return; /* nothing to check in tree diffs */
5102
5103         run_checkdiff(p, o);
5104 }
5105
5106 int diff_queue_is_empty(void)
5107 {
5108         struct diff_queue_struct *q = &diff_queued_diff;
5109         int i;
5110         for (i = 0; i < q->nr; i++)
5111                 if (!diff_unmodified_pair(q->queue[i]))
5112                         return 0;
5113         return 1;
5114 }
5115
5116 #if DIFF_DEBUG
5117 void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
5118 {
5119         fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
5120                 x, one ? one : "",
5121                 s->path,
5122                 DIFF_FILE_VALID(s) ? "valid" : "invalid",
5123                 s->mode,
5124                 s->oid_valid ? oid_to_hex(&s->oid) : "");
5125         fprintf(stderr, "queue[%d] %s size %lu\n",
5126                 x, one ? one : "",
5127                 s->size);
5128 }
5129
5130 void diff_debug_filepair(const struct diff_filepair *p, int i)
5131 {
5132         diff_debug_filespec(p->one, i, "one");
5133         diff_debug_filespec(p->two, i, "two");
5134         fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
5135                 p->score, p->status ? p->status : '?',
5136                 p->one->rename_used, p->broken_pair);
5137 }
5138
5139 void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
5140 {
5141         int i;
5142         if (msg)
5143                 fprintf(stderr, "%s\n", msg);
5144         fprintf(stderr, "q->nr = %d\n", q->nr);
5145         for (i = 0; i < q->nr; i++) {
5146                 struct diff_filepair *p = q->queue[i];
5147                 diff_debug_filepair(p, i);
5148         }
5149 }
5150 #endif
5151
5152 static void diff_resolve_rename_copy(void)
5153 {
5154         int i;
5155         struct diff_filepair *p;
5156         struct diff_queue_struct *q = &diff_queued_diff;
5157
5158         diff_debug_queue("resolve-rename-copy", q);
5159
5160         for (i = 0; i < q->nr; i++) {
5161                 p = q->queue[i];
5162                 p->status = 0; /* undecided */
5163                 if (DIFF_PAIR_UNMERGED(p))
5164                         p->status = DIFF_STATUS_UNMERGED;
5165                 else if (!DIFF_FILE_VALID(p->one))
5166                         p->status = DIFF_STATUS_ADDED;
5167                 else if (!DIFF_FILE_VALID(p->two))
5168                         p->status = DIFF_STATUS_DELETED;
5169                 else if (DIFF_PAIR_TYPE_CHANGED(p))
5170                         p->status = DIFF_STATUS_TYPE_CHANGED;
5171
5172                 /* from this point on, we are dealing with a pair
5173                  * whose both sides are valid and of the same type, i.e.
5174                  * either in-place edit or rename/copy edit.
5175                  */
5176                 else if (DIFF_PAIR_RENAME(p)) {
5177                         /*
5178                          * A rename might have re-connected a broken
5179                          * pair up, causing the pathnames to be the
5180                          * same again. If so, that's not a rename at
5181                          * all, just a modification..
5182                          *
5183                          * Otherwise, see if this source was used for
5184                          * multiple renames, in which case we decrement
5185                          * the count, and call it a copy.
5186                          */
5187                         if (!strcmp(p->one->path, p->two->path))
5188                                 p->status = DIFF_STATUS_MODIFIED;
5189                         else if (--p->one->rename_used > 0)
5190                                 p->status = DIFF_STATUS_COPIED;
5191                         else
5192                                 p->status = DIFF_STATUS_RENAMED;
5193                 }
5194                 else if (oidcmp(&p->one->oid, &p->two->oid) ||
5195                          p->one->mode != p->two->mode ||
5196                          p->one->dirty_submodule ||
5197                          p->two->dirty_submodule ||
5198                          is_null_oid(&p->one->oid))
5199                         p->status = DIFF_STATUS_MODIFIED;
5200                 else {
5201                         /* This is a "no-change" entry and should not
5202                          * happen anymore, but prepare for broken callers.
5203                          */
5204                         error("feeding unmodified %s to diffcore",
5205                               p->one->path);
5206                         p->status = DIFF_STATUS_UNKNOWN;
5207                 }
5208         }
5209         diff_debug_queue("resolve-rename-copy done", q);
5210 }
5211
5212 static int check_pair_status(struct diff_filepair *p)
5213 {
5214         switch (p->status) {
5215         case DIFF_STATUS_UNKNOWN:
5216                 return 0;
5217         case 0:
5218                 die("internal error in diff-resolve-rename-copy");
5219         default:
5220                 return 1;
5221         }
5222 }
5223
5224 static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
5225 {
5226         int fmt = opt->output_format;
5227
5228         if (fmt & DIFF_FORMAT_CHECKDIFF)
5229                 diff_flush_checkdiff(p, opt);
5230         else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
5231                 diff_flush_raw(p, opt);
5232         else if (fmt & DIFF_FORMAT_NAME) {
5233                 const char *name_a, *name_b;
5234                 name_a = p->two->path;
5235                 name_b = NULL;
5236                 strip_prefix(opt->prefix_length, &name_a, &name_b);
5237                 fprintf(opt->file, "%s", diff_line_prefix(opt));
5238                 write_name_quoted(name_a, opt->file, opt->line_termination);
5239         }
5240 }
5241
5242 static void show_file_mode_name(struct diff_options *opt, const char *newdelete, struct diff_filespec *fs)
5243 {
5244         struct strbuf sb = STRBUF_INIT;
5245         if (fs->mode)
5246                 strbuf_addf(&sb, " %s mode %06o ", newdelete, fs->mode);
5247         else
5248                 strbuf_addf(&sb, " %s ", newdelete);
5249
5250         quote_c_style(fs->path, &sb, NULL, 0);
5251         strbuf_addch(&sb, '\n');
5252         emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5253                          sb.buf, sb.len, 0);
5254         strbuf_release(&sb);
5255 }
5256
5257 static void show_mode_change(struct diff_options *opt, struct diff_filepair *p,
5258                 int show_name)
5259 {
5260         if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
5261                 struct strbuf sb = STRBUF_INIT;
5262                 strbuf_addf(&sb, " mode change %06o => %06o",
5263                             p->one->mode, p->two->mode);
5264                 if (show_name) {
5265                         strbuf_addch(&sb, ' ');
5266                         quote_c_style(p->two->path, &sb, NULL, 0);
5267                 }
5268                 strbuf_addch(&sb, '\n');
5269                 emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5270                                  sb.buf, sb.len, 0);
5271                 strbuf_release(&sb);
5272         }
5273 }
5274
5275 static void show_rename_copy(struct diff_options *opt, const char *renamecopy,
5276                 struct diff_filepair *p)
5277 {
5278         struct strbuf sb = STRBUF_INIT;
5279         struct strbuf names = STRBUF_INIT;
5280
5281         pprint_rename(&names, p->one->path, p->two->path);
5282         strbuf_addf(&sb, " %s %s (%d%%)\n",
5283                     renamecopy, names.buf, similarity_index(p));
5284         strbuf_release(&names);
5285         emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5286                                  sb.buf, sb.len, 0);
5287         show_mode_change(opt, p, 0);
5288         strbuf_release(&sb);
5289 }
5290
5291 static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
5292 {
5293         switch(p->status) {
5294         case DIFF_STATUS_DELETED:
5295                 show_file_mode_name(opt, "delete", p->one);
5296                 break;
5297         case DIFF_STATUS_ADDED:
5298                 show_file_mode_name(opt, "create", p->two);
5299                 break;
5300         case DIFF_STATUS_COPIED:
5301                 show_rename_copy(opt, "copy", p);
5302                 break;
5303         case DIFF_STATUS_RENAMED:
5304                 show_rename_copy(opt, "rename", p);
5305                 break;
5306         default:
5307                 if (p->score) {
5308                         struct strbuf sb = STRBUF_INIT;
5309                         strbuf_addstr(&sb, " rewrite ");
5310                         quote_c_style(p->two->path, &sb, NULL, 0);
5311                         strbuf_addf(&sb, " (%d%%)\n", similarity_index(p));
5312                         emit_diff_symbol(opt, DIFF_SYMBOL_SUMMARY,
5313                                          sb.buf, sb.len, 0);
5314                         strbuf_release(&sb);
5315                 }
5316                 show_mode_change(opt, p, !p->score);
5317                 break;
5318         }
5319 }
5320
5321 struct patch_id_t {
5322         git_SHA_CTX *ctx;
5323         int patchlen;
5324 };
5325
5326 static int remove_space(char *line, int len)
5327 {
5328         int i;
5329         char *dst = line;
5330         unsigned char c;
5331
5332         for (i = 0; i < len; i++)
5333                 if (!isspace((c = line[i])))
5334                         *dst++ = c;
5335
5336         return dst - line;
5337 }
5338
5339 static void patch_id_consume(void *priv, char *line, unsigned long len)
5340 {
5341         struct patch_id_t *data = priv;
5342         int new_len;
5343
5344         /* Ignore line numbers when computing the SHA1 of the patch */
5345         if (starts_with(line, "@@ -"))
5346                 return;
5347
5348         new_len = remove_space(line, len);
5349
5350         git_SHA1_Update(data->ctx, line, new_len);
5351         data->patchlen += new_len;
5352 }
5353
5354 static void patch_id_add_string(git_SHA_CTX *ctx, const char *str)
5355 {
5356         git_SHA1_Update(ctx, str, strlen(str));
5357 }
5358
5359 static void patch_id_add_mode(git_SHA_CTX *ctx, unsigned mode)
5360 {
5361         /* large enough for 2^32 in octal */
5362         char buf[12];
5363         int len = xsnprintf(buf, sizeof(buf), "%06o", mode);
5364         git_SHA1_Update(ctx, buf, len);
5365 }
5366
5367 /* returns 0 upon success, and writes result into sha1 */
5368 static int diff_get_patch_id(struct diff_options *options, struct object_id *oid, int diff_header_only)
5369 {
5370         struct diff_queue_struct *q = &diff_queued_diff;
5371         int i;
5372         git_SHA_CTX ctx;
5373         struct patch_id_t data;
5374
5375         git_SHA1_Init(&ctx);
5376         memset(&data, 0, sizeof(struct patch_id_t));
5377         data.ctx = &ctx;
5378
5379         for (i = 0; i < q->nr; i++) {
5380                 xpparam_t xpp;
5381                 xdemitconf_t xecfg;
5382                 mmfile_t mf1, mf2;
5383                 struct diff_filepair *p = q->queue[i];
5384                 int len1, len2;
5385
5386                 memset(&xpp, 0, sizeof(xpp));
5387                 memset(&xecfg, 0, sizeof(xecfg));
5388                 if (p->status == 0)
5389                         return error("internal diff status error");
5390                 if (p->status == DIFF_STATUS_UNKNOWN)
5391                         continue;
5392                 if (diff_unmodified_pair(p))
5393                         continue;
5394                 if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
5395                     (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
5396                         continue;
5397                 if (DIFF_PAIR_UNMERGED(p))
5398                         continue;
5399
5400                 diff_fill_oid_info(p->one);
5401                 diff_fill_oid_info(p->two);
5402
5403                 len1 = remove_space(p->one->path, strlen(p->one->path));
5404                 len2 = remove_space(p->two->path, strlen(p->two->path));
5405                 patch_id_add_string(&ctx, "diff--git");
5406                 patch_id_add_string(&ctx, "a/");
5407                 git_SHA1_Update(&ctx, p->one->path, len1);
5408                 patch_id_add_string(&ctx, "b/");
5409                 git_SHA1_Update(&ctx, p->two->path, len2);
5410
5411                 if (p->one->mode == 0) {
5412                         patch_id_add_string(&ctx, "newfilemode");
5413                         patch_id_add_mode(&ctx, p->two->mode);
5414                         patch_id_add_string(&ctx, "---/dev/null");
5415                         patch_id_add_string(&ctx, "+++b/");
5416                         git_SHA1_Update(&ctx, p->two->path, len2);
5417                 } else if (p->two->mode == 0) {
5418                         patch_id_add_string(&ctx, "deletedfilemode");
5419                         patch_id_add_mode(&ctx, p->one->mode);
5420                         patch_id_add_string(&ctx, "---a/");
5421                         git_SHA1_Update(&ctx, p->one->path, len1);
5422                         patch_id_add_string(&ctx, "+++/dev/null");
5423                 } else {
5424                         patch_id_add_string(&ctx, "---a/");
5425                         git_SHA1_Update(&ctx, p->one->path, len1);
5426                         patch_id_add_string(&ctx, "+++b/");
5427                         git_SHA1_Update(&ctx, p->two->path, len2);
5428                 }
5429
5430                 if (diff_header_only)
5431                         continue;
5432
5433                 if (fill_mmfile(&mf1, p->one) < 0 ||
5434                     fill_mmfile(&mf2, p->two) < 0)
5435                         return error("unable to read files to diff");
5436
5437                 if (diff_filespec_is_binary(p->one) ||
5438                     diff_filespec_is_binary(p->two)) {
5439                         git_SHA1_Update(&ctx, oid_to_hex(&p->one->oid),
5440                                         GIT_SHA1_HEXSZ);
5441                         git_SHA1_Update(&ctx, oid_to_hex(&p->two->oid),
5442                                         GIT_SHA1_HEXSZ);
5443                         continue;
5444                 }
5445
5446                 xpp.flags = 0;
5447                 xecfg.ctxlen = 3;
5448                 xecfg.flags = 0;
5449                 if (xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
5450                                   &xpp, &xecfg))
5451                         return error("unable to generate patch-id diff for %s",
5452                                      p->one->path);
5453         }
5454
5455         git_SHA1_Final(oid->hash, &ctx);
5456         return 0;
5457 }
5458
5459 int diff_flush_patch_id(struct diff_options *options, struct object_id *oid, int diff_header_only)
5460 {
5461         struct diff_queue_struct *q = &diff_queued_diff;
5462         int i;
5463         int result = diff_get_patch_id(options, oid, diff_header_only);
5464
5465         for (i = 0; i < q->nr; i++)
5466                 diff_free_filepair(q->queue[i]);
5467
5468         free(q->queue);
5469         DIFF_QUEUE_CLEAR(q);
5470
5471         return result;
5472 }
5473
5474 static int is_summary_empty(const struct diff_queue_struct *q)
5475 {
5476         int i;
5477
5478         for (i = 0; i < q->nr; i++) {
5479                 const struct diff_filepair *p = q->queue[i];
5480
5481                 switch (p->status) {
5482                 case DIFF_STATUS_DELETED:
5483                 case DIFF_STATUS_ADDED:
5484                 case DIFF_STATUS_COPIED:
5485                 case DIFF_STATUS_RENAMED:
5486                         return 0;
5487                 default:
5488                         if (p->score)
5489                                 return 0;
5490                         if (p->one->mode && p->two->mode &&
5491                             p->one->mode != p->two->mode)
5492                                 return 0;
5493                         break;
5494                 }
5495         }
5496         return 1;
5497 }
5498
5499 static const char rename_limit_warning[] =
5500 N_("inexact rename detection was skipped due to too many files.");
5501
5502 static const char degrade_cc_to_c_warning[] =
5503 N_("only found copies from modified paths due to too many files.");
5504
5505 static const char rename_limit_advice[] =
5506 N_("you may want to set your %s variable to at least "
5507    "%d and retry the command.");
5508
5509 void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
5510 {
5511         fflush(stdout);
5512         if (degraded_cc)
5513                 warning(_(degrade_cc_to_c_warning));
5514         else if (needed)
5515                 warning(_(rename_limit_warning));
5516         else
5517                 return;
5518         if (0 < needed)
5519                 warning(_(rename_limit_advice), varname, needed);
5520 }
5521
5522 static void diff_flush_patch_all_file_pairs(struct diff_options *o)
5523 {
5524         int i;
5525         static struct emitted_diff_symbols esm = EMITTED_DIFF_SYMBOLS_INIT;
5526         struct diff_queue_struct *q = &diff_queued_diff;
5527
5528         if (WSEH_NEW & WS_RULE_MASK)
5529                 BUG("WS rules bit mask overlaps with diff symbol flags");
5530
5531         if (o->color_moved)
5532                 o->emitted_symbols = &esm;
5533
5534         for (i = 0; i < q->nr; i++) {
5535                 struct diff_filepair *p = q->queue[i];
5536                 if (check_pair_status(p))
5537                         diff_flush_patch(p, o);
5538         }
5539
5540         if (o->emitted_symbols) {
5541                 if (o->color_moved) {
5542                         struct hashmap add_lines, del_lines;
5543
5544                         hashmap_init(&del_lines,
5545                                      (hashmap_cmp_fn)moved_entry_cmp, o, 0);
5546                         hashmap_init(&add_lines,
5547                                      (hashmap_cmp_fn)moved_entry_cmp, o, 0);
5548
5549                         add_lines_to_move_detection(o, &add_lines, &del_lines);
5550                         mark_color_as_moved(o, &add_lines, &del_lines);
5551                         if (o->color_moved == COLOR_MOVED_ZEBRA_DIM)
5552                                 dim_moved_lines(o);
5553
5554                         hashmap_free(&add_lines, 0);
5555                         hashmap_free(&del_lines, 0);
5556                 }
5557
5558                 for (i = 0; i < esm.nr; i++)
5559                         emit_diff_symbol_from_struct(o, &esm.buf[i]);
5560
5561                 for (i = 0; i < esm.nr; i++)
5562                         free((void *)esm.buf[i].line);
5563         }
5564         esm.nr = 0;
5565 }
5566
5567 void diff_flush(struct diff_options *options)
5568 {
5569         struct diff_queue_struct *q = &diff_queued_diff;
5570         int i, output_format = options->output_format;
5571         int separator = 0;
5572         int dirstat_by_line = 0;
5573
5574         /*
5575          * Order: raw, stat, summary, patch
5576          * or:    name/name-status/checkdiff (other bits clear)
5577          */
5578         if (!q->nr)
5579                 goto free_queue;
5580
5581         if (output_format & (DIFF_FORMAT_RAW |
5582                              DIFF_FORMAT_NAME |
5583                              DIFF_FORMAT_NAME_STATUS |
5584                              DIFF_FORMAT_CHECKDIFF)) {
5585                 for (i = 0; i < q->nr; i++) {
5586                         struct diff_filepair *p = q->queue[i];
5587                         if (check_pair_status(p))
5588                                 flush_one_pair(p, options);
5589                 }
5590                 separator++;
5591         }
5592
5593         if (output_format & DIFF_FORMAT_DIRSTAT && options->flags.dirstat_by_line)
5594                 dirstat_by_line = 1;
5595
5596         if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
5597             dirstat_by_line) {
5598                 struct diffstat_t diffstat;
5599
5600                 memset(&diffstat, 0, sizeof(struct diffstat_t));
5601                 for (i = 0; i < q->nr; i++) {
5602                         struct diff_filepair *p = q->queue[i];
5603                         if (check_pair_status(p))
5604                                 diff_flush_stat(p, options, &diffstat);
5605                 }
5606                 if (output_format & DIFF_FORMAT_NUMSTAT)
5607                         show_numstat(&diffstat, options);
5608                 if (output_format & DIFF_FORMAT_DIFFSTAT)
5609                         show_stats(&diffstat, options);
5610                 if (output_format & DIFF_FORMAT_SHORTSTAT)
5611                         show_shortstats(&diffstat, options);
5612                 if (output_format & DIFF_FORMAT_DIRSTAT && dirstat_by_line)
5613                         show_dirstat_by_line(&diffstat, options);
5614                 free_diffstat_info(&diffstat);
5615                 separator++;
5616         }
5617         if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
5618                 show_dirstat(options);
5619
5620         if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
5621                 for (i = 0; i < q->nr; i++) {
5622                         diff_summary(options, q->queue[i]);
5623                 }
5624                 separator++;
5625         }
5626
5627         if (output_format & DIFF_FORMAT_NO_OUTPUT &&
5628             options->flags.exit_with_status &&
5629             options->flags.diff_from_contents) {
5630                 /*
5631                  * run diff_flush_patch for the exit status. setting
5632                  * options->file to /dev/null should be safe, because we
5633                  * aren't supposed to produce any output anyway.
5634                  */
5635                 if (options->close_file)
5636                         fclose(options->file);
5637                 options->file = xfopen("/dev/null", "w");
5638                 options->close_file = 1;
5639                 options->color_moved = 0;
5640                 for (i = 0; i < q->nr; i++) {
5641                         struct diff_filepair *p = q->queue[i];
5642                         if (check_pair_status(p))
5643                                 diff_flush_patch(p, options);
5644                         if (options->found_changes)
5645                                 break;
5646                 }
5647         }
5648
5649         if (output_format & DIFF_FORMAT_PATCH) {
5650                 if (separator) {
5651                         emit_diff_symbol(options, DIFF_SYMBOL_SEPARATOR, NULL, 0, 0);
5652                         if (options->stat_sep)
5653                                 /* attach patch instead of inline */
5654                                 emit_diff_symbol(options, DIFF_SYMBOL_STAT_SEP,
5655                                                  NULL, 0, 0);
5656                 }
5657
5658                 diff_flush_patch_all_file_pairs(options);
5659         }
5660
5661         if (output_format & DIFF_FORMAT_CALLBACK)
5662                 options->format_callback(q, options, options->format_callback_data);
5663
5664         for (i = 0; i < q->nr; i++)
5665                 diff_free_filepair(q->queue[i]);
5666 free_queue:
5667         free(q->queue);
5668         DIFF_QUEUE_CLEAR(q);
5669         if (options->close_file)
5670                 fclose(options->file);
5671
5672         /*
5673          * Report the content-level differences with HAS_CHANGES;
5674          * diff_addremove/diff_change does not set the bit when
5675          * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
5676          */
5677         if (options->flags.diff_from_contents) {
5678                 if (options->found_changes)
5679                         options->flags.has_changes = 1;
5680                 else
5681                         options->flags.has_changes = 0;
5682         }
5683 }
5684
5685 static int match_filter(const struct diff_options *options, const struct diff_filepair *p)
5686 {
5687         return (((p->status == DIFF_STATUS_MODIFIED) &&
5688                  ((p->score &&
5689                    filter_bit_tst(DIFF_STATUS_FILTER_BROKEN, options)) ||
5690                   (!p->score &&
5691                    filter_bit_tst(DIFF_STATUS_MODIFIED, options)))) ||
5692                 ((p->status != DIFF_STATUS_MODIFIED) &&
5693                  filter_bit_tst(p->status, options)));
5694 }
5695
5696 static void diffcore_apply_filter(struct diff_options *options)
5697 {
5698         int i;
5699         struct diff_queue_struct *q = &diff_queued_diff;
5700         struct diff_queue_struct outq;
5701
5702         DIFF_QUEUE_CLEAR(&outq);
5703
5704         if (!options->filter)
5705                 return;
5706
5707         if (filter_bit_tst(DIFF_STATUS_FILTER_AON, options)) {
5708                 int found;
5709                 for (i = found = 0; !found && i < q->nr; i++) {
5710                         if (match_filter(options, q->queue[i]))
5711                                 found++;
5712                 }
5713                 if (found)
5714                         return;
5715
5716                 /* otherwise we will clear the whole queue
5717                  * by copying the empty outq at the end of this
5718                  * function, but first clear the current entries
5719                  * in the queue.
5720                  */
5721                 for (i = 0; i < q->nr; i++)
5722                         diff_free_filepair(q->queue[i]);
5723         }
5724         else {
5725                 /* Only the matching ones */
5726                 for (i = 0; i < q->nr; i++) {
5727                         struct diff_filepair *p = q->queue[i];
5728                         if (match_filter(options, p))
5729                                 diff_q(&outq, p);
5730                         else
5731                                 diff_free_filepair(p);
5732                 }
5733         }
5734         free(q->queue);
5735         *q = outq;
5736 }
5737
5738 /* Check whether two filespecs with the same mode and size are identical */
5739 static int diff_filespec_is_identical(struct diff_filespec *one,
5740                                       struct diff_filespec *two)
5741 {
5742         if (S_ISGITLINK(one->mode))
5743                 return 0;
5744         if (diff_populate_filespec(one, 0))
5745                 return 0;
5746         if (diff_populate_filespec(two, 0))
5747                 return 0;
5748         return !memcmp(one->data, two->data, one->size);
5749 }
5750
5751 static int diff_filespec_check_stat_unmatch(struct diff_filepair *p)
5752 {
5753         if (p->done_skip_stat_unmatch)
5754                 return p->skip_stat_unmatch_result;
5755
5756         p->done_skip_stat_unmatch = 1;
5757         p->skip_stat_unmatch_result = 0;
5758         /*
5759          * 1. Entries that come from stat info dirtiness
5760          *    always have both sides (iow, not create/delete),
5761          *    one side of the object name is unknown, with
5762          *    the same mode and size.  Keep the ones that
5763          *    do not match these criteria.  They have real
5764          *    differences.
5765          *
5766          * 2. At this point, the file is known to be modified,
5767          *    with the same mode and size, and the object
5768          *    name of one side is unknown.  Need to inspect
5769          *    the identical contents.
5770          */
5771         if (!DIFF_FILE_VALID(p->one) || /* (1) */
5772             !DIFF_FILE_VALID(p->two) ||
5773             (p->one->oid_valid && p->two->oid_valid) ||
5774             (p->one->mode != p->two->mode) ||
5775             diff_populate_filespec(p->one, CHECK_SIZE_ONLY) ||
5776             diff_populate_filespec(p->two, CHECK_SIZE_ONLY) ||
5777             (p->one->size != p->two->size) ||
5778             !diff_filespec_is_identical(p->one, p->two)) /* (2) */
5779                 p->skip_stat_unmatch_result = 1;
5780         return p->skip_stat_unmatch_result;
5781 }
5782
5783 static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
5784 {
5785         int i;
5786         struct diff_queue_struct *q = &diff_queued_diff;
5787         struct diff_queue_struct outq;
5788         DIFF_QUEUE_CLEAR(&outq);
5789
5790         for (i = 0; i < q->nr; i++) {
5791                 struct diff_filepair *p = q->queue[i];
5792
5793                 if (diff_filespec_check_stat_unmatch(p))
5794                         diff_q(&outq, p);
5795                 else {
5796                         /*
5797                          * The caller can subtract 1 from skip_stat_unmatch
5798                          * to determine how many paths were dirty only
5799                          * due to stat info mismatch.
5800                          */
5801                         if (!diffopt->flags.no_index)
5802                                 diffopt->skip_stat_unmatch++;
5803                         diff_free_filepair(p);
5804                 }
5805         }
5806         free(q->queue);
5807         *q = outq;
5808 }
5809
5810 static int diffnamecmp(const void *a_, const void *b_)
5811 {
5812         const struct diff_filepair *a = *((const struct diff_filepair **)a_);
5813         const struct diff_filepair *b = *((const struct diff_filepair **)b_);
5814         const char *name_a, *name_b;
5815
5816         name_a = a->one ? a->one->path : a->two->path;
5817         name_b = b->one ? b->one->path : b->two->path;
5818         return strcmp(name_a, name_b);
5819 }
5820
5821 void diffcore_fix_diff_index(struct diff_options *options)
5822 {
5823         struct diff_queue_struct *q = &diff_queued_diff;
5824         QSORT(q->queue, q->nr, diffnamecmp);
5825 }
5826
5827 void diffcore_std(struct diff_options *options)
5828 {
5829         /* NOTE please keep the following in sync with diff_tree_combined() */
5830         if (options->skip_stat_unmatch)
5831                 diffcore_skip_stat_unmatch(options);
5832         if (!options->found_follow) {
5833                 /* See try_to_follow_renames() in tree-diff.c */
5834                 if (options->break_opt != -1)
5835                         diffcore_break(options->break_opt);
5836                 if (options->detect_rename)
5837                         diffcore_rename(options);
5838                 if (options->break_opt != -1)
5839                         diffcore_merge_broken();
5840         }
5841         if (options->pickaxe_opts & DIFF_PICKAXE_KINDS_MASK)
5842                 diffcore_pickaxe(options);
5843         if (options->orderfile)
5844                 diffcore_order(options->orderfile);
5845         if (!options->found_follow)
5846                 /* See try_to_follow_renames() in tree-diff.c */
5847                 diff_resolve_rename_copy();
5848         diffcore_apply_filter(options);
5849
5850         if (diff_queued_diff.nr && !options->flags.diff_from_contents)
5851                 options->flags.has_changes = 1;
5852         else
5853                 options->flags.has_changes = 0;
5854
5855         options->found_follow = 0;
5856 }
5857
5858 int diff_result_code(struct diff_options *opt, int status)
5859 {
5860         int result = 0;
5861
5862         diff_warn_rename_limit("diff.renameLimit",
5863                                opt->needed_rename_limit,
5864                                opt->degraded_cc_to_c);
5865         if (!opt->flags.exit_with_status &&
5866             !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
5867                 return status;
5868         if (opt->flags.exit_with_status &&
5869             opt->flags.has_changes)
5870                 result |= 01;
5871         if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
5872             opt->flags.check_failed)
5873                 result |= 02;
5874         return result;
5875 }
5876
5877 int diff_can_quit_early(struct diff_options *opt)
5878 {
5879         return (opt->flags.quick &&
5880                 !opt->filter &&
5881                 opt->flags.has_changes);
5882 }
5883
5884 /*
5885  * Shall changes to this submodule be ignored?
5886  *
5887  * Submodule changes can be configured to be ignored separately for each path,
5888  * but that configuration can be overridden from the command line.
5889  */
5890 static int is_submodule_ignored(const char *path, struct diff_options *options)
5891 {
5892         int ignored = 0;
5893         struct diff_flags orig_flags = options->flags;
5894         if (!options->flags.override_submodule_config)
5895                 set_diffopt_flags_from_submodule_config(options, path);
5896         if (options->flags.ignore_submodules)
5897                 ignored = 1;
5898         options->flags = orig_flags;
5899         return ignored;
5900 }
5901
5902 void diff_addremove(struct diff_options *options,
5903                     int addremove, unsigned mode,
5904                     const struct object_id *oid,
5905                     int oid_valid,
5906                     const char *concatpath, unsigned dirty_submodule)
5907 {
5908         struct diff_filespec *one, *two;
5909
5910         if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
5911                 return;
5912
5913         /* This may look odd, but it is a preparation for
5914          * feeding "there are unchanged files which should
5915          * not produce diffs, but when you are doing copy
5916          * detection you would need them, so here they are"
5917          * entries to the diff-core.  They will be prefixed
5918          * with something like '=' or '*' (I haven't decided
5919          * which but should not make any difference).
5920          * Feeding the same new and old to diff_change()
5921          * also has the same effect.
5922          * Before the final output happens, they are pruned after
5923          * merged into rename/copy pairs as appropriate.
5924          */
5925         if (options->flags.reverse_diff)
5926                 addremove = (addremove == '+' ? '-' :
5927                              addremove == '-' ? '+' : addremove);
5928
5929         if (options->prefix &&
5930             strncmp(concatpath, options->prefix, options->prefix_length))
5931                 return;
5932
5933         one = alloc_filespec(concatpath);
5934         two = alloc_filespec(concatpath);
5935
5936         if (addremove != '+')
5937                 fill_filespec(one, oid, oid_valid, mode);
5938         if (addremove != '-') {
5939                 fill_filespec(two, oid, oid_valid, mode);
5940                 two->dirty_submodule = dirty_submodule;
5941         }
5942
5943         diff_queue(&diff_queued_diff, one, two);
5944         if (!options->flags.diff_from_contents)
5945                 options->flags.has_changes = 1;
5946 }
5947
5948 void diff_change(struct diff_options *options,
5949                  unsigned old_mode, unsigned new_mode,
5950                  const struct object_id *old_oid,
5951                  const struct object_id *new_oid,
5952                  int old_oid_valid, int new_oid_valid,
5953                  const char *concatpath,
5954                  unsigned old_dirty_submodule, unsigned new_dirty_submodule)
5955 {
5956         struct diff_filespec *one, *two;
5957         struct diff_filepair *p;
5958
5959         if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
5960             is_submodule_ignored(concatpath, options))
5961                 return;
5962
5963         if (options->flags.reverse_diff) {
5964                 SWAP(old_mode, new_mode);
5965                 SWAP(old_oid, new_oid);
5966                 SWAP(old_oid_valid, new_oid_valid);
5967                 SWAP(old_dirty_submodule, new_dirty_submodule);
5968         }
5969
5970         if (options->prefix &&
5971             strncmp(concatpath, options->prefix, options->prefix_length))
5972                 return;
5973
5974         one = alloc_filespec(concatpath);
5975         two = alloc_filespec(concatpath);
5976         fill_filespec(one, old_oid, old_oid_valid, old_mode);
5977         fill_filespec(two, new_oid, new_oid_valid, new_mode);
5978         one->dirty_submodule = old_dirty_submodule;
5979         two->dirty_submodule = new_dirty_submodule;
5980         p = diff_queue(&diff_queued_diff, one, two);
5981
5982         if (options->flags.diff_from_contents)
5983                 return;
5984
5985         if (options->flags.quick && options->skip_stat_unmatch &&
5986             !diff_filespec_check_stat_unmatch(p))
5987                 return;
5988
5989         options->flags.has_changes = 1;
5990 }
5991
5992 struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
5993 {
5994         struct diff_filepair *pair;
5995         struct diff_filespec *one, *two;
5996
5997         if (options->prefix &&
5998             strncmp(path, options->prefix, options->prefix_length))
5999                 return NULL;
6000
6001         one = alloc_filespec(path);
6002         two = alloc_filespec(path);
6003         pair = diff_queue(&diff_queued_diff, one, two);
6004         pair->is_unmerged = 1;
6005         return pair;
6006 }
6007
6008 static char *run_textconv(const char *pgm, struct diff_filespec *spec,
6009                 size_t *outsize)
6010 {
6011         struct diff_tempfile *temp;
6012         const char *argv[3];
6013         const char **arg = argv;
6014         struct child_process child = CHILD_PROCESS_INIT;
6015         struct strbuf buf = STRBUF_INIT;
6016         int err = 0;
6017
6018         temp = prepare_temp_file(spec->path, spec);
6019         *arg++ = pgm;
6020         *arg++ = temp->name;
6021         *arg = NULL;
6022
6023         child.use_shell = 1;
6024         child.argv = argv;
6025         child.out = -1;
6026         if (start_command(&child)) {
6027                 remove_tempfile();
6028                 return NULL;
6029         }
6030
6031         if (strbuf_read(&buf, child.out, 0) < 0)
6032                 err = error("error reading from textconv command '%s'", pgm);
6033         close(child.out);
6034
6035         if (finish_command(&child) || err) {
6036                 strbuf_release(&buf);
6037                 remove_tempfile();
6038                 return NULL;
6039         }
6040         remove_tempfile();
6041
6042         return strbuf_detach(&buf, outsize);
6043 }
6044
6045 size_t fill_textconv(struct userdiff_driver *driver,
6046                      struct diff_filespec *df,
6047                      char **outbuf)
6048 {
6049         size_t size;
6050
6051         if (!driver) {
6052                 if (!DIFF_FILE_VALID(df)) {
6053                         *outbuf = "";
6054                         return 0;
6055                 }
6056                 if (diff_populate_filespec(df, 0))
6057                         die("unable to read files to diff");
6058                 *outbuf = df->data;
6059                 return df->size;
6060         }
6061
6062         if (!driver->textconv)
6063                 BUG("fill_textconv called with non-textconv driver");
6064
6065         if (driver->textconv_cache && df->oid_valid) {
6066                 *outbuf = notes_cache_get(driver->textconv_cache,
6067                                           &df->oid,
6068                                           &size);
6069                 if (*outbuf)
6070                         return size;
6071         }
6072
6073         *outbuf = run_textconv(driver->textconv, df, &size);
6074         if (!*outbuf)
6075                 die("unable to read files to diff");
6076
6077         if (driver->textconv_cache && df->oid_valid) {
6078                 /* ignore errors, as we might be in a readonly repository */
6079                 notes_cache_put(driver->textconv_cache, &df->oid, *outbuf,
6080                                 size);
6081                 /*
6082                  * we could save up changes and flush them all at the end,
6083                  * but we would need an extra call after all diffing is done.
6084                  * Since generating a cache entry is the slow path anyway,
6085                  * this extra overhead probably isn't a big deal.
6086                  */
6087                 notes_cache_write(driver->textconv_cache);
6088         }
6089
6090         return size;
6091 }
6092
6093 int textconv_object(const char *path,
6094                     unsigned mode,
6095                     const struct object_id *oid,
6096                     int oid_valid,
6097                     char **buf,
6098                     unsigned long *buf_size)
6099 {
6100         struct diff_filespec *df;
6101         struct userdiff_driver *textconv;
6102
6103         df = alloc_filespec(path);
6104         fill_filespec(df, oid, oid_valid, mode);
6105         textconv = get_textconv(df);
6106         if (!textconv) {
6107                 free_filespec(df);
6108                 return 0;
6109         }
6110
6111         *buf_size = fill_textconv(textconv, df, buf);
6112         free_filespec(df);
6113         return 1;
6114 }
6115
6116 void setup_diff_pager(struct diff_options *opt)
6117 {
6118         /*
6119          * If the user asked for our exit code, then either they want --quiet
6120          * or --exit-code. We should definitely not bother with a pager in the
6121          * former case, as we will generate no output. Since we still properly
6122          * report our exit code even when a pager is run, we _could_ run a
6123          * pager with --exit-code. But since we have not done so historically,
6124          * and because it is easy to find people oneline advising "git diff
6125          * --exit-code" in hooks and other scripts, we do not do so.
6126          */
6127         if (!opt->flags.exit_with_status &&
6128             check_pager_config("diff") != 0)
6129                 setup_pager();
6130 }