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

   1 /*
   2  * Copyright (C) 2005 Junio C Hamano
   3  */
   4 #include "cache.h"
   5 #include "tempfile.h"
   6 #include "quote.h"
   7 #include "diff.h"
   8 #include "diffcore.h"
   9 #include "delta.h"
  10 #include "xdiff-interface.h"
  11 #include "color.h"
  12 #include "attr.h"
  13 #include "run-command.h"
  14 #include "utf8.h"
  15 #include "userdiff.h"
  16 #include "submodule-config.h"
  17 #include "submodule.h"
  18 #include "ll-merge.h"
  19 #include "string-list.h"
  20 #include "argv-array.h"
  21
  22 #ifdef NO_FAST_WORKING_DIRECTORY
  23 #define FAST_WORKING_DIRECTORY 0
  24 #else
  25 #define FAST_WORKING_DIRECTORY 1
  26 #endif
  27
  28 static int diff_detect_rename_default;
  29 static int diff_rename_limit_default = 400;
  30 static int diff_suppress_blank_empty;
  31 static int diff_use_color_default = -1;
  32 static int diff_context_default = 3;
  33 static const char *diff_word_regex_cfg;
  34 static const char *external_diff_cmd_cfg;
  35 static const char *diff_order_file_cfg;
  36 int diff_auto_refresh_index = 1;
  37 static int diff_mnemonic_prefix;
  38 static int diff_no_prefix;
  39 static int diff_stat_graph_width;
  40 static int diff_dirstat_permille_default = 30;
  41 static struct diff_options default_diff_options;
  42 static long diff_algorithm;
  43
  44 static char diff_colors[][COLOR_MAXLEN] = {
  45         GIT_COLOR_RESET,
  46         GIT_COLOR_NORMAL,       /* CONTEXT */
  47         GIT_COLOR_BOLD,         /* METAINFO */
  48         GIT_COLOR_CYAN,         /* FRAGINFO */
  49         GIT_COLOR_RED,          /* OLD */
  50         GIT_COLOR_GREEN,        /* NEW */
  51         GIT_COLOR_YELLOW,       /* COMMIT */
  52         GIT_COLOR_BG_RED,       /* WHITESPACE */
  53         GIT_COLOR_NORMAL,       /* FUNCINFO */
  54 };
  55
  56 static int parse_diff_color_slot(const char *var)
  57 {
  58         if (!strcasecmp(var, "context") || !strcasecmp(var, "plain"))
  59                 return DIFF_CONTEXT;
  60         if (!strcasecmp(var, "meta"))
  61                 return DIFF_METAINFO;
  62         if (!strcasecmp(var, "frag"))
  63                 return DIFF_FRAGINFO;
  64         if (!strcasecmp(var, "old"))
  65                 return DIFF_FILE_OLD;
  66         if (!strcasecmp(var, "new"))
  67                 return DIFF_FILE_NEW;
  68         if (!strcasecmp(var, "commit"))
  69                 return DIFF_COMMIT;
  70         if (!strcasecmp(var, "whitespace"))
  71                 return DIFF_WHITESPACE;
  72         if (!strcasecmp(var, "func"))
  73                 return DIFF_FUNCINFO;
  74         return -1;
  75 }
  76
  77 static int parse_dirstat_params(struct diff_options *options, const char *params_string,
  78                                 struct strbuf *errmsg)
  79 {
  80         char *params_copy = xstrdup(params_string);
  81         struct string_list params = STRING_LIST_INIT_NODUP;
  82         int ret = 0;
  83         int i;
  84
  85         if (*params_copy)
  86                 string_list_split_in_place(&params, params_copy, ',', -1);
  87         for (i = 0; i < params.nr; i++) {
  88                 const char *p = params.items[i].string;
  89                 if (!strcmp(p, "changes")) {
  90                         DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
  91                         DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
  92                 } else if (!strcmp(p, "lines")) {
  93                         DIFF_OPT_SET(options, DIRSTAT_BY_LINE);
  94                         DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
  95                 } else if (!strcmp(p, "files")) {
  96                         DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
  97                         DIFF_OPT_SET(options, DIRSTAT_BY_FILE);
  98                 } else if (!strcmp(p, "noncumulative")) {
  99                         DIFF_OPT_CLR(options, DIRSTAT_CUMULATIVE);
 100                 } else if (!strcmp(p, "cumulative")) {
 101                         DIFF_OPT_SET(options, DIRSTAT_CUMULATIVE);
 102                 } else if (isdigit(*p)) {
 103                         char *end;
 104                         int permille = strtoul(p, &end, 10) * 10;
 105                         if (*end == '.' && isdigit(*++end)) {
 106                                 /* only use first digit */
 107                                 permille += *end - '0';
 108                                 /* .. and ignore any further digits */
 109                                 while (isdigit(*++end))
 110                                         ; /* nothing */
 111                         }
 112                         if (!*end)
 113                                 options->dirstat_permille = permille;
 114                         else {
 115                                 strbuf_addf(errmsg, _("  Failed to parse dirstat cut-off percentage '%s'\n"),
 116                                             p);
 117                                 ret++;
 118                         }
 119                 } else {
 120                         strbuf_addf(errmsg, _("  Unknown dirstat parameter '%s'\n"), p);
 121                         ret++;
 122                 }
 123
 124         }
 125         string_list_clear(&params, 0);
 126         free(params_copy);
 127         return ret;
 128 }
 129
 130 static int parse_submodule_params(struct diff_options *options, const char *value)
 131 {
 132         if (!strcmp(value, "log"))
 133                 DIFF_OPT_SET(options, SUBMODULE_LOG);
 134         else if (!strcmp(value, "short"))
 135                 DIFF_OPT_CLR(options, SUBMODULE_LOG);
 136         else
 137                 return -1;
 138         return 0;
 139 }
 140
 141 static int git_config_rename(const char *var, const char *value)
 142 {
 143         if (!value)
 144                 return DIFF_DETECT_RENAME;
 145         if (!strcasecmp(value, "copies") || !strcasecmp(value, "copy"))
 146                 return  DIFF_DETECT_COPY;
 147         return git_config_bool(var,value) ? DIFF_DETECT_RENAME : 0;
 148 }
 149
 150 long parse_algorithm_value(const char *value)
 151 {
 152         if (!value)
 153                 return -1;
 154         else if (!strcasecmp(value, "myers") || !strcasecmp(value, "default"))
 155                 return 0;
 156         else if (!strcasecmp(value, "minimal"))
 157                 return XDF_NEED_MINIMAL;
 158         else if (!strcasecmp(value, "patience"))
 159                 return XDF_PATIENCE_DIFF;
 160         else if (!strcasecmp(value, "histogram"))
 161                 return XDF_HISTOGRAM_DIFF;
 162         return -1;
 163 }
 164
 165 /*
 166  * These are to give UI layer defaults.
 167  * The core-level commands such as git-diff-files should
 168  * never be affected by the setting of diff.renames
 169  * the user happens to have in the configuration file.
 170  */
 171 void init_diff_ui_defaults(void)
 172 {
 173         diff_detect_rename_default = 1;
 174 }
 175
 176 int git_diff_ui_config(const char *var, const char *value, void *cb)
 177 {
 178         if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 179                 diff_use_color_default = git_config_colorbool(var, value);
 180                 return 0;
 181         }
 182         if (!strcmp(var, "diff.context")) {
 183                 diff_context_default = git_config_int(var, value);
 184                 if (diff_context_default < 0)
 185                         return -1;
 186                 return 0;
 187         }
 188         if (!strcmp(var, "diff.renames")) {
 189                 diff_detect_rename_default = git_config_rename(var, value);
 190                 return 0;
 191         }
 192         if (!strcmp(var, "diff.autorefreshindex")) {
 193                 diff_auto_refresh_index = git_config_bool(var, value);
 194                 return 0;
 195         }
 196         if (!strcmp(var, "diff.mnemonicprefix")) {
 197                 diff_mnemonic_prefix = git_config_bool(var, value);
 198                 return 0;
 199         }
 200         if (!strcmp(var, "diff.noprefix")) {
 201                 diff_no_prefix = git_config_bool(var, value);
 202                 return 0;
 203         }
 204         if (!strcmp(var, "diff.statgraphwidth")) {
 205                 diff_stat_graph_width = git_config_int(var, value);
 206                 return 0;
 207         }
 208         if (!strcmp(var, "diff.external"))
 209                 return git_config_string(&external_diff_cmd_cfg, var, value);
 210         if (!strcmp(var, "diff.wordregex"))
 211                 return git_config_string(&diff_word_regex_cfg, var, value);
 212         if (!strcmp(var, "diff.orderfile"))
 213                 return git_config_pathname(&diff_order_file_cfg, var, value);
 214
 215         if (!strcmp(var, "diff.ignoresubmodules"))
 216                 handle_ignore_submodules_arg(&default_diff_options, value);
 217
 218         if (!strcmp(var, "diff.submodule")) {
 219                 if (parse_submodule_params(&default_diff_options, value))
 220                         warning(_("Unknown value for 'diff.submodule' config variable: '%s'"),
 221                                 value);
 222                 return 0;
 223         }
 224
 225         if (!strcmp(var, "diff.algorithm")) {
 226                 diff_algorithm = parse_algorithm_value(value);
 227                 if (diff_algorithm < 0)
 228                         return -1;
 229                 return 0;
 230         }
 231
 232         if (git_color_config(var, value, cb) < 0)
 233                 return -1;
 234
 235         return git_diff_basic_config(var, value, cb);
 236 }
 237
 238 int git_diff_basic_config(const char *var, const char *value, void *cb)
 239 {
 240         const char *name;
 241
 242         if (!strcmp(var, "diff.renamelimit")) {
 243                 diff_rename_limit_default = git_config_int(var, value);
 244                 return 0;
 245         }
 246
 247         if (userdiff_config(var, value) < 0)
 248                 return -1;
 249
 250         if (skip_prefix(var, "diff.color.", &name) ||
 251             skip_prefix(var, "color.diff.", &name)) {
 252                 int slot = parse_diff_color_slot(name);
 253                 if (slot < 0)
 254                         return 0;
 255                 if (!value)
 256                         return config_error_nonbool(var);
 257                 return color_parse(value, diff_colors[slot]);
 258         }
 259
 260         /* like GNU diff's --suppress-blank-empty option  */
 261         if (!strcmp(var, "diff.suppressblankempty") ||
 262                         /* for backwards compatibility */
 263                         !strcmp(var, "diff.suppress-blank-empty")) {
 264                 diff_suppress_blank_empty = git_config_bool(var, value);
 265                 return 0;
 266         }
 267
 268         if (!strcmp(var, "diff.dirstat")) {
 269                 struct strbuf errmsg = STRBUF_INIT;
 270                 default_diff_options.dirstat_permille = diff_dirstat_permille_default;
 271                 if (parse_dirstat_params(&default_diff_options, value, &errmsg))
 272                         warning(_("Found errors in 'diff.dirstat' config variable:\n%s"),
 273                                 errmsg.buf);
 274                 strbuf_release(&errmsg);
 275                 diff_dirstat_permille_default = default_diff_options.dirstat_permille;
 276                 return 0;
 277         }
 278
 279         if (starts_with(var, "submodule."))
 280                 return parse_submodule_config_option(var, value);
 281
 282         return git_default_config(var, value, cb);
 283 }
 284
 285 static char *quote_two(const char *one, const char *two)
 286 {
 287         int need_one = quote_c_style(one, NULL, NULL, 1);
 288         int need_two = quote_c_style(two, NULL, NULL, 1);
 289         struct strbuf res = STRBUF_INIT;
 290
 291         if (need_one + need_two) {
 292                 strbuf_addch(&res, '"');
 293                 quote_c_style(one, &res, NULL, 1);
 294                 quote_c_style(two, &res, NULL, 1);
 295                 strbuf_addch(&res, '"');
 296         } else {
 297                 strbuf_addstr(&res, one);
 298                 strbuf_addstr(&res, two);
 299         }
 300         return strbuf_detach(&res, NULL);
 301 }
 302
 303 static const char *external_diff(void)
 304 {
 305         static const char *external_diff_cmd = NULL;
 306         static int done_preparing = 0;
 307
 308         if (done_preparing)
 309                 return external_diff_cmd;
 310         external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 311         if (!external_diff_cmd)
 312                 external_diff_cmd = external_diff_cmd_cfg;
 313         done_preparing = 1;
 314         return external_diff_cmd;
 315 }
 316
 317 /*
 318  * Keep track of files used for diffing. Sometimes such an entry
 319  * refers to a temporary file, sometimes to an existing file, and
 320  * sometimes to "/dev/null".
 321  */
 322 static struct diff_tempfile {
 323         /*
 324          * filename external diff should read from, or NULL if this
 325          * entry is currently not in use:
 326          */
 327         const char *name;
 328
 329         char hex[GIT_SHA1_HEXSZ + 1];
 330         char mode[10];
 331
 332         /*
 333          * If this diff_tempfile instance refers to a temporary file,
 334          * this tempfile object is used to manage its lifetime.
 335          */
 336         struct tempfile tempfile;
 337 } diff_temp[2];
 338
 339 typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
 340
 341 struct emit_callback {
 342         int color_diff;
 343         unsigned ws_rule;
 344         int blank_at_eof_in_preimage;
 345         int blank_at_eof_in_postimage;
 346         int lno_in_preimage;
 347         int lno_in_postimage;
 348         sane_truncate_fn truncate;
 349         const char **label_path;
 350         struct diff_words_data *diff_words;
 351         struct diff_options *opt;
 352         int *found_changesp;
 353         struct strbuf *header;
 354 };
 355
 356 static int count_lines(const char *data, int size)
 357 {
 358         int count, ch, completely_empty = 1, nl_just_seen = 0;
 359         count = 0;
 360         while (0 < size--) {
 361                 ch = *data++;
 362                 if (ch == '\n') {
 363                         count++;
 364                         nl_just_seen = 1;
 365                         completely_empty = 0;
 366                 }
 367                 else {
 368                         nl_just_seen = 0;
 369                         completely_empty = 0;
 370                 }
 371         }
 372         if (completely_empty)
 373                 return 0;
 374         if (!nl_just_seen)
 375                 count++; /* no trailing newline */
 376         return count;
 377 }
 378
 379 static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 380 {
 381         if (!DIFF_FILE_VALID(one)) {
 382                 mf->ptr = (char *)""; /* does not matter */
 383                 mf->size = 0;
 384                 return 0;
 385         }
 386         else if (diff_populate_filespec(one, 0))
 387                 return -1;
 388
 389         mf->ptr = one->data;
 390         mf->size = one->size;
 391         return 0;
 392 }
 393
 394 /* like fill_mmfile, but only for size, so we can avoid retrieving blob */
 395 static unsigned long diff_filespec_size(struct diff_filespec *one)
 396 {
 397         if (!DIFF_FILE_VALID(one))
 398                 return 0;
 399         diff_populate_filespec(one, CHECK_SIZE_ONLY);
 400         return one->size;
 401 }
 402
 403 static int count_trailing_blank(mmfile_t *mf, unsigned ws_rule)
 404 {
 405         char *ptr = mf->ptr;
 406         long size = mf->size;
 407         int cnt = 0;
 408
 409         if (!size)
 410                 return cnt;
 411         ptr += size - 1; /* pointing at the very end */
 412         if (*ptr != '\n')
 413                 ; /* incomplete line */
 414         else
 415                 ptr--; /* skip the last LF */
 416         while (mf->ptr < ptr) {
 417                 char *prev_eol;
 418                 for (prev_eol = ptr; mf->ptr <= prev_eol; prev_eol--)
 419                         if (*prev_eol == '\n')
 420                                 break;
 421                 if (!ws_blank_line(prev_eol + 1, ptr - prev_eol, ws_rule))
 422                         break;
 423                 cnt++;
 424                 ptr = prev_eol - 1;
 425         }
 426         return cnt;
 427 }
 428
 429 static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
 430                                struct emit_callback *ecbdata)
 431 {
 432         int l1, l2, at;
 433         unsigned ws_rule = ecbdata->ws_rule;
 434         l1 = count_trailing_blank(mf1, ws_rule);
 435         l2 = count_trailing_blank(mf2, ws_rule);
 436         if (l2 <= l1) {
 437                 ecbdata->blank_at_eof_in_preimage = 0;
 438                 ecbdata->blank_at_eof_in_postimage = 0;
 439                 return;
 440         }
 441         at = count_lines(mf1->ptr, mf1->size);
 442         ecbdata->blank_at_eof_in_preimage = (at - l1) + 1;
 443
 444         at = count_lines(mf2->ptr, mf2->size);
 445         ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
 446 }
 447
 448 static void emit_line_0(struct diff_options *o, const char *set, const char *reset,
 449                         int first, const char *line, int len)
 450 {
 451         int has_trailing_newline, has_trailing_carriage_return;
 452         int nofirst;
 453         FILE *file = o->file;
 454
 455         fputs(diff_line_prefix(o), file);
 456
 457         if (len == 0) {
 458                 has_trailing_newline = (first == '\n');
 459                 has_trailing_carriage_return = (!has_trailing_newline &&
 460                                                 (first == '\r'));
 461                 nofirst = has_trailing_newline || has_trailing_carriage_return;
 462         } else {
 463                 has_trailing_newline = (len > 0 && line[len-1] == '\n');
 464                 if (has_trailing_newline)
 465                         len--;
 466                 has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
 467                 if (has_trailing_carriage_return)
 468                         len--;
 469                 nofirst = 0;
 470         }
 471
 472         if (len || !nofirst) {
 473                 fputs(set, file);
 474                 if (!nofirst)
 475                         fputc(first, file);
 476                 fwrite(line, len, 1, file);
 477                 fputs(reset, file);
 478         }
 479         if (has_trailing_carriage_return)
 480                 fputc('\r', file);
 481         if (has_trailing_newline)
 482                 fputc('\n', file);
 483 }
 484
 485 static void emit_line(struct diff_options *o, const char *set, const char *reset,
 486                       const char *line, int len)
 487 {
 488         emit_line_0(o, set, reset, line[0], line+1, len-1);
 489 }
 490
 491 static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
 492 {
 493         if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
 494               ecbdata->blank_at_eof_in_preimage &&
 495               ecbdata->blank_at_eof_in_postimage &&
 496               ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
 497               ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
 498                 return 0;
 499         return ws_blank_line(line, len, ecbdata->ws_rule);
 500 }
 501
 502 static void emit_line_checked(const char *reset,
 503                               struct emit_callback *ecbdata,
 504                               const char *line, int len,
 505                               enum color_diff color,
 506                               unsigned ws_error_highlight,
 507                               char sign)
 508 {
 509         const char *set = diff_get_color(ecbdata->color_diff, color);
 510         const char *ws = NULL;
 511
 512         if (ecbdata->opt->ws_error_highlight & ws_error_highlight) {
 513                 ws = diff_get_color(ecbdata->color_diff, DIFF_WHITESPACE);
 514                 if (!*ws)
 515                         ws = NULL;
 516         }
 517
 518         if (!ws)
 519                 emit_line_0(ecbdata->opt, set, reset, sign, line, len);
 520         else if (sign == '+' && new_blank_line_at_eof(ecbdata, line, len))
 521                 /* Blank line at EOF - paint '+' as well */
 522                 emit_line_0(ecbdata->opt, ws, reset, sign, line, len);
 523         else {
 524                 /* Emit just the prefix, then the rest. */
 525                 emit_line_0(ecbdata->opt, set, reset, sign, "", 0);
 526                 ws_check_emit(line, len, ecbdata->ws_rule,
 527                               ecbdata->opt->file, set, reset, ws);
 528         }
 529 }
 530
 531 static void emit_add_line(const char *reset,
 532                           struct emit_callback *ecbdata,
 533                           const char *line, int len)
 534 {
 535         emit_line_checked(reset, ecbdata, line, len,
 536                           DIFF_FILE_NEW, WSEH_NEW, '+');
 537 }
 538
 539 static void emit_del_line(const char *reset,
 540                           struct emit_callback *ecbdata,
 541                           const char *line, int len)
 542 {
 543         emit_line_checked(reset, ecbdata, line, len,
 544                           DIFF_FILE_OLD, WSEH_OLD, '-');
 545 }
 546
 547 static void emit_context_line(const char *reset,
 548                               struct emit_callback *ecbdata,
 549                               const char *line, int len)
 550 {
 551         emit_line_checked(reset, ecbdata, line, len,
 552                           DIFF_CONTEXT, WSEH_CONTEXT, ' ');
 553 }
 554
 555 static void emit_hunk_header(struct emit_callback *ecbdata,
 556                              const char *line, int len)
 557 {
 558         const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
 559         const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
 560         const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
 561         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
 562         static const char atat[2] = { '@', '@' };
 563         const char *cp, *ep;
 564         struct strbuf msgbuf = STRBUF_INIT;
 565         int org_len = len;
 566         int i = 1;
 567
 568         /*
 569          * As a hunk header must begin with "@@ -<old>, +<new> @@",
 570          * it always is at least 10 bytes long.
 571          */
 572         if (len < 10 ||
 573             memcmp(line, atat, 2) ||
 574             !(ep = memmem(line + 2, len - 2, atat, 2))) {
 575                 emit_line(ecbdata->opt, context, reset, line, len);
 576                 return;
 577         }
 578         ep += 2; /* skip over @@ */
 579
 580         /* The hunk header in fraginfo color */
 581         strbuf_addstr(&msgbuf, frag);
 582         strbuf_add(&msgbuf, line, ep - line);
 583         strbuf_addstr(&msgbuf, reset);
 584
 585         /*
 586          * trailing "\r\n"
 587          */
 588         for ( ; i < 3; i++)
 589                 if (line[len - i] == '\r' || line[len - i] == '\n')
 590                         len--;
 591
 592         /* blank before the func header */
 593         for (cp = ep; ep - line < len; ep++)
 594                 if (*ep != ' ' && *ep != '\t')
 595                         break;
 596         if (ep != cp) {
 597                 strbuf_addstr(&msgbuf, context);
 598                 strbuf_add(&msgbuf, cp, ep - cp);
 599                 strbuf_addstr(&msgbuf, reset);
 600         }
 601
 602         if (ep < line + len) {
 603                 strbuf_addstr(&msgbuf, func);
 604                 strbuf_add(&msgbuf, ep, line + len - ep);
 605                 strbuf_addstr(&msgbuf, reset);
 606         }
 607
 608         strbuf_add(&msgbuf, line + len, org_len - len);
 609         emit_line(ecbdata->opt, "", "", msgbuf.buf, msgbuf.len);
 610         strbuf_release(&msgbuf);
 611 }
 612
 613 static struct diff_tempfile *claim_diff_tempfile(void) {
 614         int i;
 615         for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
 616                 if (!diff_temp[i].name)
 617                         return diff_temp + i;
 618         die("BUG: diff is failing to clean up its tempfiles");
 619 }
 620
 621 static void remove_tempfile(void)
 622 {
 623         int i;
 624         for (i = 0; i < ARRAY_SIZE(diff_temp); i++) {
 625                 if (is_tempfile_active(&diff_temp[i].tempfile))
 626                         delete_tempfile(&diff_temp[i].tempfile);
 627                 diff_temp[i].name = NULL;
 628         }
 629 }
 630
 631 static void print_line_count(FILE *file, int count)
 632 {
 633         switch (count) {
 634         case 0:
 635                 fprintf(file, "0,0");
 636                 break;
 637         case 1:
 638                 fprintf(file, "1");
 639                 break;
 640         default:
 641                 fprintf(file, "1,%d", count);
 642                 break;
 643         }
 644 }
 645
 646 static void emit_rewrite_lines(struct emit_callback *ecb,
 647                                int prefix, const char *data, int size)
 648 {
 649         const char *endp = NULL;
 650         static const char *nneof = " No newline at end of file\n";
 651         const char *reset = diff_get_color(ecb->color_diff, DIFF_RESET);
 652
 653         while (0 < size) {
 654                 int len;
 655
 656                 endp = memchr(data, '\n', size);
 657                 len = endp ? (endp - data + 1) : size;
 658                 if (prefix != '+') {
 659                         ecb->lno_in_preimage++;
 660                         emit_del_line(reset, ecb, data, len);
 661                 } else {
 662                         ecb->lno_in_postimage++;
 663                         emit_add_line(reset, ecb, data, len);
 664                 }
 665                 size -= len;
 666                 data += len;
 667         }
 668         if (!endp) {
 669                 const char *context = diff_get_color(ecb->color_diff,
 670                                                      DIFF_CONTEXT);
 671                 putc('\n', ecb->opt->file);
 672                 emit_line_0(ecb->opt, context, reset, '\\',
 673                             nneof, strlen(nneof));
 674         }
 675 }
 676
 677 static void emit_rewrite_diff(const char *name_a,
 678                               const char *name_b,
 679                               struct diff_filespec *one,
 680                               struct diff_filespec *two,
 681                               struct userdiff_driver *textconv_one,
 682                               struct userdiff_driver *textconv_two,
 683                               struct diff_options *o)
 684 {
 685         int lc_a, lc_b;
 686         const char *name_a_tab, *name_b_tab;
 687         const char *metainfo = diff_get_color(o->use_color, DIFF_METAINFO);
 688         const char *fraginfo = diff_get_color(o->use_color, DIFF_FRAGINFO);
 689         const char *reset = diff_get_color(o->use_color, DIFF_RESET);
 690         static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
 691         const char *a_prefix, *b_prefix;
 692         char *data_one, *data_two;
 693         size_t size_one, size_two;
 694         struct emit_callback ecbdata;
 695         const char *line_prefix = diff_line_prefix(o);
 696
 697         if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
 698                 a_prefix = o->b_prefix;
 699                 b_prefix = o->a_prefix;
 700         } else {
 701                 a_prefix = o->a_prefix;
 702                 b_prefix = o->b_prefix;
 703         }
 704
 705         name_a += (*name_a == '/');
 706         name_b += (*name_b == '/');
 707         name_a_tab = strchr(name_a, ' ') ? "\t" : "";
 708         name_b_tab = strchr(name_b, ' ') ? "\t" : "";
 709
 710         strbuf_reset(&a_name);
 711         strbuf_reset(&b_name);
 712         quote_two_c_style(&a_name, a_prefix, name_a, 0);
 713         quote_two_c_style(&b_name, b_prefix, name_b, 0);
 714
 715         size_one = fill_textconv(textconv_one, one, &data_one);
 716         size_two = fill_textconv(textconv_two, two, &data_two);
 717
 718         memset(&ecbdata, 0, sizeof(ecbdata));
 719         ecbdata.color_diff = want_color(o->use_color);
 720         ecbdata.found_changesp = &o->found_changes;
 721         ecbdata.ws_rule = whitespace_rule(name_b);
 722         ecbdata.opt = o;
 723         if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
 724                 mmfile_t mf1, mf2;
 725                 mf1.ptr = (char *)data_one;
 726                 mf2.ptr = (char *)data_two;
 727                 mf1.size = size_one;
 728                 mf2.size = size_two;
 729                 check_blank_at_eof(&mf1, &mf2, &ecbdata);
 730         }
 731         ecbdata.lno_in_preimage = 1;
 732         ecbdata.lno_in_postimage = 1;
 733
 734         lc_a = count_lines(data_one, size_one);
 735         lc_b = count_lines(data_two, size_two);
 736         fprintf(o->file,
 737                 "%s%s--- %s%s%s\n%s%s+++ %s%s%s\n%s%s@@ -",
 738                 line_prefix, metainfo, a_name.buf, name_a_tab, reset,
 739                 line_prefix, metainfo, b_name.buf, name_b_tab, reset,
 740                 line_prefix, fraginfo);
 741         if (!o->irreversible_delete)
 742                 print_line_count(o->file, lc_a);
 743         else
 744                 fprintf(o->file, "?,?");
 745         fprintf(o->file, " +");
 746         print_line_count(o->file, lc_b);
 747         fprintf(o->file, " @@%s\n", reset);
 748         if (lc_a && !o->irreversible_delete)
 749                 emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
 750         if (lc_b)
 751                 emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
 752         if (textconv_one)
 753                 free((char *)data_one);
 754         if (textconv_two)
 755                 free((char *)data_two);
 756 }
 757
 758 struct diff_words_buffer {
 759         mmfile_t text;
 760         long alloc;
 761         struct diff_words_orig {
 762                 const char *begin, *end;
 763         } *orig;
 764         int orig_nr, orig_alloc;
 765 };
 766
 767 static void diff_words_append(char *line, unsigned long len,
 768                 struct diff_words_buffer *buffer)
 769 {
 770         ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
 771         line++;
 772         len--;
 773         memcpy(buffer->text.ptr + buffer->text.size, line, len);
 774         buffer->text.size += len;
 775         buffer->text.ptr[buffer->text.size] = '\0';
 776 }
 777
 778 struct diff_words_style_elem {
 779         const char *prefix;
 780         const char *suffix;
 781         const char *color; /* NULL; filled in by the setup code if
 782                             * color is enabled */
 783 };
 784
 785 struct diff_words_style {
 786         enum diff_words_type type;
 787         struct diff_words_style_elem new, old, ctx;
 788         const char *newline;
 789 };
 790
 791 static struct diff_words_style diff_words_styles[] = {
 792         { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
 793         { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
 794         { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
 795 };
 796
 797 struct diff_words_data {
 798         struct diff_words_buffer minus, plus;
 799         const char *current_plus;
 800         int last_minus;
 801         struct diff_options *opt;
 802         regex_t *word_regex;
 803         enum diff_words_type type;
 804         struct diff_words_style *style;
 805 };
 806
 807 static int fn_out_diff_words_write_helper(FILE *fp,
 808                                           struct diff_words_style_elem *st_el,
 809                                           const char *newline,
 810                                           size_t count, const char *buf,
 811                                           const char *line_prefix)
 812 {
 813         int print = 0;
 814
 815         while (count) {
 816                 char *p = memchr(buf, '\n', count);
 817                 if (print)
 818                         fputs(line_prefix, fp);
 819                 if (p != buf) {
 820                         if (st_el->color && fputs(st_el->color, fp) < 0)
 821                                 return -1;
 822                         if (fputs(st_el->prefix, fp) < 0 ||
 823                             fwrite(buf, p ? p - buf : count, 1, fp) != 1 ||
 824                             fputs(st_el->suffix, fp) < 0)
 825                                 return -1;
 826                         if (st_el->color && *st_el->color
 827                             && fputs(GIT_COLOR_RESET, fp) < 0)
 828                                 return -1;
 829                 }
 830                 if (!p)
 831                         return 0;
 832                 if (fputs(newline, fp) < 0)
 833                         return -1;
 834                 count -= p + 1 - buf;
 835                 buf = p + 1;
 836                 print = 1;
 837         }
 838         return 0;
 839 }
 840
 841 /*
 842  * '--color-words' algorithm can be described as:
 843  *
 844  *   1. collect a the minus/plus lines of a diff hunk, divided into
 845  *      minus-lines and plus-lines;
 846  *
 847  *   2. break both minus-lines and plus-lines into words and
 848  *      place them into two mmfile_t with one word for each line;
 849  *
 850  *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
 851  *
 852  * And for the common parts of the both file, we output the plus side text.
 853  * diff_words->current_plus is used to trace the current position of the plus file
 854  * which printed. diff_words->last_minus is used to trace the last minus word
 855  * printed.
 856  *
 857  * For '--graph' to work with '--color-words', we need to output the graph prefix
 858  * on each line of color words output. Generally, there are two conditions on
 859  * which we should output the prefix.
 860  *
 861  *   1. diff_words->last_minus == 0 &&
 862  *      diff_words->current_plus == diff_words->plus.text.ptr
 863  *
 864  *      that is: the plus text must start as a new line, and if there is no minus
 865  *      word printed, a graph prefix must be printed.
 866  *
 867  *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
 868  *      *(diff_words->current_plus - 1) == '\n'
 869  *
 870  *      that is: a graph prefix must be printed following a '\n'
 871  */
 872 static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
 873 {
 874         if ((diff_words->last_minus == 0 &&
 875                 diff_words->current_plus == diff_words->plus.text.ptr) ||
 876                 (diff_words->current_plus > diff_words->plus.text.ptr &&
 877                 *(diff_words->current_plus - 1) == '\n')) {
 878                 return 1;
 879         } else {
 880                 return 0;
 881         }
 882 }
 883
 884 static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
 885 {
 886         struct diff_words_data *diff_words = priv;
 887         struct diff_words_style *style = diff_words->style;
 888         int minus_first, minus_len, plus_first, plus_len;
 889         const char *minus_begin, *minus_end, *plus_begin, *plus_end;
 890         struct diff_options *opt = diff_words->opt;
 891         const char *line_prefix;
 892
 893         if (line[0] != '@' || parse_hunk_header(line, len,
 894                         &minus_first, &minus_len, &plus_first, &plus_len))
 895                 return;
 896
 897         assert(opt);
 898         line_prefix = diff_line_prefix(opt);
 899
 900         /* POSIX requires that first be decremented by one if len == 0... */
 901         if (minus_len) {
 902                 minus_begin = diff_words->minus.orig[minus_first].begin;
 903                 minus_end =
 904                         diff_words->minus.orig[minus_first + minus_len - 1].end;
 905         } else
 906                 minus_begin = minus_end =
 907                         diff_words->minus.orig[minus_first].end;
 908
 909         if (plus_len) {
 910                 plus_begin = diff_words->plus.orig[plus_first].begin;
 911                 plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
 912         } else
 913                 plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
 914
 915         if (color_words_output_graph_prefix(diff_words)) {
 916                 fputs(line_prefix, diff_words->opt->file);
 917         }
 918         if (diff_words->current_plus != plus_begin) {
 919                 fn_out_diff_words_write_helper(diff_words->opt->file,
 920                                 &style->ctx, style->newline,
 921                                 plus_begin - diff_words->current_plus,
 922                                 diff_words->current_plus, line_prefix);
 923                 if (*(plus_begin - 1) == '\n')
 924                         fputs(line_prefix, diff_words->opt->file);
 925         }
 926         if (minus_begin != minus_end) {
 927                 fn_out_diff_words_write_helper(diff_words->opt->file,
 928                                 &style->old, style->newline,
 929                                 minus_end - minus_begin, minus_begin,
 930                                 line_prefix);
 931         }
 932         if (plus_begin != plus_end) {
 933                 fn_out_diff_words_write_helper(diff_words->opt->file,
 934                                 &style->new, style->newline,
 935                                 plus_end - plus_begin, plus_begin,
 936                                 line_prefix);
 937         }
 938
 939         diff_words->current_plus = plus_end;
 940         diff_words->last_minus = minus_first;
 941 }
 942
 943 /* This function starts looking at *begin, and returns 0 iff a word was found. */
 944 static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
 945                 int *begin, int *end)
 946 {
 947         if (word_regex && *begin < buffer->size) {
 948                 regmatch_t match[1];
 949                 if (!regexec(word_regex, buffer->ptr + *begin, 1, match, 0)) {
 950                         char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
 951                                         '\n', match[0].rm_eo - match[0].rm_so);
 952                         *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
 953                         *begin += match[0].rm_so;
 954                         return *begin >= *end;
 955                 }
 956                 return -1;
 957         }
 958
 959         /* find the next word */
 960         while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
 961                 (*begin)++;
 962         if (*begin >= buffer->size)
 963                 return -1;
 964
 965         /* find the end of the word */
 966         *end = *begin + 1;
 967         while (*end < buffer->size && !isspace(buffer->ptr[*end]))
 968                 (*end)++;
 969
 970         return 0;
 971 }
 972
 973 /*
 974  * This function splits the words in buffer->text, stores the list with
 975  * newline separator into out, and saves the offsets of the original words
 976  * in buffer->orig.
 977  */
 978 static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
 979                 regex_t *word_regex)
 980 {
 981         int i, j;
 982         long alloc = 0;
 983
 984         out->size = 0;
 985         out->ptr = NULL;
 986
 987         /* fake an empty "0th" word */
 988         ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
 989         buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
 990         buffer->orig_nr = 1;
 991
 992         for (i = 0; i < buffer->text.size; i++) {
 993                 if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
 994                         return;
 995
 996                 /* store original boundaries */
 997                 ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
 998                                 buffer->orig_alloc);
 999                 buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
1000                 buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
1001                 buffer->orig_nr++;
1002
1003                 /* store one word */
1004                 ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
1005                 memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
1006                 out->ptr[out->size + j - i] = '\n';
1007                 out->size += j - i + 1;
1008
1009                 i = j - 1;
1010         }
1011 }
1012
1013 /* this executes the word diff on the accumulated buffers */
1014 static void diff_words_show(struct diff_words_data *diff_words)
1015 {
1016         xpparam_t xpp;
1017         xdemitconf_t xecfg;
1018         mmfile_t minus, plus;
1019         struct diff_words_style *style = diff_words->style;
1020
1021         struct diff_options *opt = diff_words->opt;
1022         const char *line_prefix;
1023
1024         assert(opt);
1025         line_prefix = diff_line_prefix(opt);
1026
1027         /* special case: only removal */
1028         if (!diff_words->plus.text.size) {
1029                 fputs(line_prefix, diff_words->opt->file);
1030                 fn_out_diff_words_write_helper(diff_words->opt->file,
1031                         &style->old, style->newline,
1032                         diff_words->minus.text.size,
1033                         diff_words->minus.text.ptr, line_prefix);
1034                 diff_words->minus.text.size = 0;
1035                 return;
1036         }
1037
1038         diff_words->current_plus = diff_words->plus.text.ptr;
1039         diff_words->last_minus = 0;
1040
1041         memset(&xpp, 0, sizeof(xpp));
1042         memset(&xecfg, 0, sizeof(xecfg));
1043         diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
1044         diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
1045         xpp.flags = 0;
1046         /* as only the hunk header will be parsed, we need a 0-context */
1047         xecfg.ctxlen = 0;
1048         if (xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
1049                           &xpp, &xecfg))
1050                 die("unable to generate word diff");
1051         free(minus.ptr);
1052         free(plus.ptr);
1053         if (diff_words->current_plus != diff_words->plus.text.ptr +
1054                         diff_words->plus.text.size) {
1055                 if (color_words_output_graph_prefix(diff_words))
1056                         fputs(line_prefix, diff_words->opt->file);
1057                 fn_out_diff_words_write_helper(diff_words->opt->file,
1058                         &style->ctx, style->newline,
1059                         diff_words->plus.text.ptr + diff_words->plus.text.size
1060                         - diff_words->current_plus, diff_words->current_plus,
1061                         line_prefix);
1062         }
1063         diff_words->minus.text.size = diff_words->plus.text.size = 0;
1064 }
1065
1066 /* In "color-words" mode, show word-diff of words accumulated in the buffer */
1067 static void diff_words_flush(struct emit_callback *ecbdata)
1068 {
1069         if (ecbdata->diff_words->minus.text.size ||
1070             ecbdata->diff_words->plus.text.size)
1071                 diff_words_show(ecbdata->diff_words);
1072 }
1073
1074 static void diff_filespec_load_driver(struct diff_filespec *one)
1075 {
1076         /* Use already-loaded driver */
1077         if (one->driver)
1078                 return;
1079
1080         if (S_ISREG(one->mode))
1081                 one->driver = userdiff_find_by_path(one->path);
1082
1083         /* Fallback to default settings */
1084         if (!one->driver)
1085                 one->driver = userdiff_find_by_name("default");
1086 }
1087
1088 static const char *userdiff_word_regex(struct diff_filespec *one)
1089 {
1090         diff_filespec_load_driver(one);
1091         return one->driver->word_regex;
1092 }
1093
1094 static void init_diff_words_data(struct emit_callback *ecbdata,
1095                                  struct diff_options *orig_opts,
1096                                  struct diff_filespec *one,
1097                                  struct diff_filespec *two)
1098 {
1099         int i;
1100         struct diff_options *o = xmalloc(sizeof(struct diff_options));
1101         memcpy(o, orig_opts, sizeof(struct diff_options));
1102
1103         ecbdata->diff_words =
1104                 xcalloc(1, sizeof(struct diff_words_data));
1105         ecbdata->diff_words->type = o->word_diff;
1106         ecbdata->diff_words->opt = o;
1107         if (!o->word_regex)
1108                 o->word_regex = userdiff_word_regex(one);
1109         if (!o->word_regex)
1110                 o->word_regex = userdiff_word_regex(two);
1111         if (!o->word_regex)
1112                 o->word_regex = diff_word_regex_cfg;
1113         if (o->word_regex) {
1114                 ecbdata->diff_words->word_regex = (regex_t *)
1115                         xmalloc(sizeof(regex_t));
1116                 if (regcomp(ecbdata->diff_words->word_regex,
1117                             o->word_regex,
1118                             REG_EXTENDED | REG_NEWLINE))
1119                         die ("Invalid regular expression: %s",
1120                              o->word_regex);
1121         }
1122         for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
1123                 if (o->word_diff == diff_words_styles[i].type) {
1124                         ecbdata->diff_words->style =
1125                                 &diff_words_styles[i];
1126                         break;
1127                 }
1128         }
1129         if (want_color(o->use_color)) {
1130                 struct diff_words_style *st = ecbdata->diff_words->style;
1131                 st->old.color = diff_get_color_opt(o, DIFF_FILE_OLD);
1132                 st->new.color = diff_get_color_opt(o, DIFF_FILE_NEW);
1133                 st->ctx.color = diff_get_color_opt(o, DIFF_CONTEXT);
1134         }
1135 }
1136
1137 static void free_diff_words_data(struct emit_callback *ecbdata)
1138 {
1139         if (ecbdata->diff_words) {
1140                 diff_words_flush(ecbdata);
1141                 free (ecbdata->diff_words->opt);
1142                 free (ecbdata->diff_words->minus.text.ptr);
1143                 free (ecbdata->diff_words->minus.orig);
1144                 free (ecbdata->diff_words->plus.text.ptr);
1145                 free (ecbdata->diff_words->plus.orig);
1146                 if (ecbdata->diff_words->word_regex) {
1147                         regfree(ecbdata->diff_words->word_regex);
1148                         free(ecbdata->diff_words->word_regex);
1149                 }
1150                 free(ecbdata->diff_words);
1151                 ecbdata->diff_words = NULL;
1152         }
1153 }
1154
1155 const char *diff_get_color(int diff_use_color, enum color_diff ix)
1156 {
1157         if (want_color(diff_use_color))
1158                 return diff_colors[ix];
1159         return "";
1160 }
1161
1162 const char *diff_line_prefix(struct diff_options *opt)
1163 {
1164         struct strbuf *msgbuf;
1165         if (!opt->output_prefix)
1166                 return "";
1167
1168         msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
1169         return msgbuf->buf;
1170 }
1171
1172 static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
1173 {
1174         const char *cp;
1175         unsigned long allot;
1176         size_t l = len;
1177
1178         if (ecb->truncate)
1179                 return ecb->truncate(line, len);
1180         cp = line;
1181         allot = l;
1182         while (0 < l) {
1183                 (void) utf8_width(&cp, &l);
1184                 if (!cp)
1185                         break; /* truncated in the middle? */
1186         }
1187         return allot - l;
1188 }
1189
1190 static void find_lno(const char *line, struct emit_callback *ecbdata)
1191 {
1192         const char *p;
1193         ecbdata->lno_in_preimage = 0;
1194         ecbdata->lno_in_postimage = 0;
1195         p = strchr(line, '-');
1196         if (!p)
1197                 return; /* cannot happen */
1198         ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
1199         p = strchr(p, '+');
1200         if (!p)
1201                 return; /* cannot happen */
1202         ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
1203 }
1204
1205 static void fn_out_consume(void *priv, char *line, unsigned long len)
1206 {
1207         struct emit_callback *ecbdata = priv;
1208         const char *meta = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
1209         const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
1210         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1211         struct diff_options *o = ecbdata->opt;
1212         const char *line_prefix = diff_line_prefix(o);
1213
1214         if (ecbdata->header) {
1215                 fprintf(ecbdata->opt->file, "%s", ecbdata->header->buf);
1216                 strbuf_reset(ecbdata->header);
1217                 ecbdata->header = NULL;
1218         }
1219         *(ecbdata->found_changesp) = 1;
1220
1221         if (ecbdata->label_path[0]) {
1222                 const char *name_a_tab, *name_b_tab;
1223
1224                 name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
1225                 name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
1226
1227                 fprintf(ecbdata->opt->file, "%s%s--- %s%s%s\n",
1228                         line_prefix, meta, ecbdata->label_path[0], reset, name_a_tab);
1229                 fprintf(ecbdata->opt->file, "%s%s+++ %s%s%s\n",
1230                         line_prefix, meta, ecbdata->label_path[1], reset, name_b_tab);
1231                 ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
1232         }
1233
1234         if (diff_suppress_blank_empty
1235             && len == 2 && line[0] == ' ' && line[1] == '\n') {
1236                 line[0] = '\n';
1237                 len = 1;
1238         }
1239
1240         if (line[0] == '@') {
1241                 if (ecbdata->diff_words)
1242                         diff_words_flush(ecbdata);
1243                 len = sane_truncate_line(ecbdata, line, len);
1244                 find_lno(line, ecbdata);
1245                 emit_hunk_header(ecbdata, line, len);
1246                 if (line[len-1] != '\n')
1247                         putc('\n', ecbdata->opt->file);
1248                 return;
1249         }
1250
1251         if (len < 1) {
1252                 emit_line(ecbdata->opt, reset, reset, line, len);
1253                 if (ecbdata->diff_words
1254                     && ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN)
1255                         fputs("~\n", ecbdata->opt->file);
1256                 return;
1257         }
1258
1259         if (ecbdata->diff_words) {
1260                 if (line[0] == '-') {
1261                         diff_words_append(line, len,
1262                                           &ecbdata->diff_words->minus);
1263                         return;
1264                 } else if (line[0] == '+') {
1265                         diff_words_append(line, len,
1266                                           &ecbdata->diff_words->plus);
1267                         return;
1268                 } else if (starts_with(line, "\\ ")) {
1269                         /*
1270                          * Eat the "no newline at eof" marker as if we
1271                          * saw a "+" or "-" line with nothing on it,
1272                          * and return without diff_words_flush() to
1273                          * defer processing. If this is the end of
1274                          * preimage, more "+" lines may come after it.
1275                          */
1276                         return;
1277                 }
1278                 diff_words_flush(ecbdata);
1279                 if (ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN) {
1280                         emit_line(ecbdata->opt, context, reset, line, len);
1281                         fputs("~\n", ecbdata->opt->file);
1282                 } else {
1283                         /*
1284                          * Skip the prefix character, if any.  With
1285                          * diff_suppress_blank_empty, there may be
1286                          * none.
1287                          */
1288                         if (line[0] != '\n') {
1289                               line++;
1290                               len--;
1291                         }
1292                         emit_line(ecbdata->opt, context, reset, line, len);
1293                 }
1294                 return;
1295         }
1296
1297         switch (line[0]) {
1298         case '+':
1299                 ecbdata->lno_in_postimage++;
1300                 emit_add_line(reset, ecbdata, line + 1, len - 1);
1301                 break;
1302         case '-':
1303                 ecbdata->lno_in_preimage++;
1304                 emit_del_line(reset, ecbdata, line + 1, len - 1);
1305                 break;
1306         case ' ':
1307                 ecbdata->lno_in_postimage++;
1308                 ecbdata->lno_in_preimage++;
1309                 emit_context_line(reset, ecbdata, line + 1, len - 1);
1310                 break;
1311         default:
1312                 /* incomplete line at the end */
1313                 ecbdata->lno_in_preimage++;
1314                 emit_line(ecbdata->opt,
1315                           diff_get_color(ecbdata->color_diff, DIFF_CONTEXT),
1316                           reset, line, len);
1317                 break;
1318         }
1319 }
1320
1321 static char *pprint_rename(const char *a, const char *b)
1322 {
1323         const char *old = a;
1324         const char *new = b;
1325         struct strbuf name = STRBUF_INIT;
1326         int pfx_length, sfx_length;
1327         int pfx_adjust_for_slash;
1328         int len_a = strlen(a);
1329         int len_b = strlen(b);
1330         int a_midlen, b_midlen;
1331         int qlen_a = quote_c_style(a, NULL, NULL, 0);
1332         int qlen_b = quote_c_style(b, NULL, NULL, 0);
1333
1334         if (qlen_a || qlen_b) {
1335                 quote_c_style(a, &name, NULL, 0);
1336                 strbuf_addstr(&name, " => ");
1337                 quote_c_style(b, &name, NULL, 0);
1338                 return strbuf_detach(&name, NULL);
1339         }
1340
1341         /* Find common prefix */
1342         pfx_length = 0;
1343         while (*old && *new && *old == *new) {
1344                 if (*old == '/')
1345                         pfx_length = old - a + 1;
1346                 old++;
1347                 new++;
1348         }
1349
1350         /* Find common suffix */
1351         old = a + len_a;
1352         new = b + len_b;
1353         sfx_length = 0;
1354         /*
1355          * If there is a common prefix, it must end in a slash.  In
1356          * that case we let this loop run 1 into the prefix to see the
1357          * same slash.
1358          *
1359          * If there is no common prefix, we cannot do this as it would
1360          * underrun the input strings.
1361          */
1362         pfx_adjust_for_slash = (pfx_length ? 1 : 0);
1363         while (a + pfx_length - pfx_adjust_for_slash <= old &&
1364                b + pfx_length - pfx_adjust_for_slash <= new &&
1365                *old == *new) {
1366                 if (*old == '/')
1367                         sfx_length = len_a - (old - a);
1368                 old--;
1369                 new--;
1370         }
1371
1372         /*
1373          * pfx{mid-a => mid-b}sfx
1374          * {pfx-a => pfx-b}sfx
1375          * pfx{sfx-a => sfx-b}
1376          * name-a => name-b
1377          */
1378         a_midlen = len_a - pfx_length - sfx_length;
1379         b_midlen = len_b - pfx_length - sfx_length;
1380         if (a_midlen < 0)
1381                 a_midlen = 0;
1382         if (b_midlen < 0)
1383                 b_midlen = 0;
1384
1385         strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
1386         if (pfx_length + sfx_length) {
1387                 strbuf_add(&name, a, pfx_length);
1388                 strbuf_addch(&name, '{');
1389         }
1390         strbuf_add(&name, a + pfx_length, a_midlen);
1391         strbuf_addstr(&name, " => ");
1392         strbuf_add(&name, b + pfx_length, b_midlen);
1393         if (pfx_length + sfx_length) {
1394                 strbuf_addch(&name, '}');
1395                 strbuf_add(&name, a + len_a - sfx_length, sfx_length);
1396         }
1397         return strbuf_detach(&name, NULL);
1398 }
1399
1400 struct diffstat_t {
1401         int nr;
1402         int alloc;
1403         struct diffstat_file {
1404                 char *from_name;
1405                 char *name;
1406                 char *print_name;
1407                 unsigned is_unmerged:1;
1408                 unsigned is_binary:1;
1409                 unsigned is_renamed:1;
1410                 unsigned is_interesting:1;
1411                 uintmax_t added, deleted;
1412         } **files;
1413 };
1414
1415 static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
1416                                           const char *name_a,
1417                                           const char *name_b)
1418 {
1419         struct diffstat_file *x;
1420         x = xcalloc(1, sizeof(*x));
1421         ALLOC_GROW(diffstat->files, diffstat->nr + 1, diffstat->alloc);
1422         diffstat->files[diffstat->nr++] = x;
1423         if (name_b) {
1424                 x->from_name = xstrdup(name_a);
1425                 x->name = xstrdup(name_b);
1426                 x->is_renamed = 1;
1427         }
1428         else {
1429                 x->from_name = NULL;
1430                 x->name = xstrdup(name_a);
1431         }
1432         return x;
1433 }
1434
1435 static void diffstat_consume(void *priv, char *line, unsigned long len)
1436 {
1437         struct diffstat_t *diffstat = priv;
1438         struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
1439
1440         if (line[0] == '+')
1441                 x->added++;
1442         else if (line[0] == '-')
1443                 x->deleted++;
1444 }
1445
1446 const char mime_boundary_leader[] = "------------";
1447
1448 static int scale_linear(int it, int width, int max_change)
1449 {
1450         if (!it)
1451                 return 0;
1452         /*
1453          * make sure that at least one '-' or '+' is printed if
1454          * there is any change to this path. The easiest way is to
1455          * scale linearly as if the alloted width is one column shorter
1456          * than it is, and then add 1 to the result.
1457          */
1458         return 1 + (it * (width - 1) / max_change);
1459 }
1460
1461 static void show_name(FILE *file,
1462                       const char *prefix, const char *name, int len)
1463 {
1464         fprintf(file, " %s%-*s |", prefix, len, name);
1465 }
1466
1467 static void show_graph(FILE *file, char ch, int cnt, const char *set, const char *reset)
1468 {
1469         if (cnt <= 0)
1470                 return;
1471         fprintf(file, "%s", set);
1472         while (cnt--)
1473                 putc(ch, file);
1474         fprintf(file, "%s", reset);
1475 }
1476
1477 static void fill_print_name(struct diffstat_file *file)
1478 {
1479         char *pname;
1480
1481         if (file->print_name)
1482                 return;
1483
1484         if (!file->is_renamed) {
1485                 struct strbuf buf = STRBUF_INIT;
1486                 if (quote_c_style(file->name, &buf, NULL, 0)) {
1487                         pname = strbuf_detach(&buf, NULL);
1488                 } else {
1489                         pname = file->name;
1490                         strbuf_release(&buf);
1491                 }
1492         } else {
1493                 pname = pprint_rename(file->from_name, file->name);
1494         }
1495         file->print_name = pname;
1496 }
1497
1498 int print_stat_summary(FILE *fp, int files, int insertions, int deletions)
1499 {
1500         struct strbuf sb = STRBUF_INIT;
1501         int ret;
1502
1503         if (!files) {
1504                 assert(insertions == 0 && deletions == 0);
1505                 return fprintf(fp, "%s\n", " 0 files changed");
1506         }
1507
1508         strbuf_addf(&sb,
1509                     (files == 1) ? " %d file changed" : " %d files changed",
1510                     files);
1511
1512         /*
1513          * For binary diff, the caller may want to print "x files
1514          * changed" with insertions == 0 && deletions == 0.
1515          *
1516          * Not omitting "0 insertions(+), 0 deletions(-)" in this case
1517          * is probably less confusing (i.e skip over "2 files changed
1518          * but nothing about added/removed lines? Is this a bug in Git?").
1519          */
1520         if (insertions || deletions == 0) {
1521                 strbuf_addf(&sb,
1522                             (insertions == 1) ? ", %d insertion(+)" : ", %d insertions(+)",
1523                             insertions);
1524         }
1525
1526         if (deletions || insertions == 0) {
1527                 strbuf_addf(&sb,
1528                             (deletions == 1) ? ", %d deletion(-)" : ", %d deletions(-)",
1529                             deletions);
1530         }
1531         strbuf_addch(&sb, '\n');
1532         ret = fputs(sb.buf, fp);
1533         strbuf_release(&sb);
1534         return ret;
1535 }
1536
1537 static void show_stats(struct diffstat_t *data, struct diff_options *options)
1538 {
1539         int i, len, add, del, adds = 0, dels = 0;
1540         uintmax_t max_change = 0, max_len = 0;
1541         int total_files = data->nr, count;
1542         int width, name_width, graph_width, number_width = 0, bin_width = 0;
1543         const char *reset, *add_c, *del_c;
1544         const char *line_prefix = "";
1545         int extra_shown = 0;
1546
1547         if (data->nr == 0)
1548                 return;
1549
1550         line_prefix = diff_line_prefix(options);
1551         count = options->stat_count ? options->stat_count : data->nr;
1552
1553         reset = diff_get_color_opt(options, DIFF_RESET);
1554         add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
1555         del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
1556
1557         /*
1558          * Find the longest filename and max number of changes
1559          */
1560         for (i = 0; (i < count) && (i < data->nr); i++) {
1561                 struct diffstat_file *file = data->files[i];
1562                 uintmax_t change = file->added + file->deleted;
1563
1564                 if (!file->is_interesting && (change == 0)) {
1565                         count++; /* not shown == room for one more */
1566                         continue;
1567                 }
1568                 fill_print_name(file);
1569                 len = strlen(file->print_name);
1570                 if (max_len < len)
1571                         max_len = len;
1572
1573                 if (file->is_unmerged) {
1574                         /* "Unmerged" is 8 characters */
1575                         bin_width = bin_width < 8 ? 8 : bin_width;
1576                         continue;
1577                 }
1578                 if (file->is_binary) {
1579                         /* "Bin XXX -> YYY bytes" */
1580                         int w = 14 + decimal_width(file->added)
1581                                 + decimal_width(file->deleted);
1582                         bin_width = bin_width < w ? w : bin_width;
1583                         /* Display change counts aligned with "Bin" */
1584                         number_width = 3;
1585                         continue;
1586                 }
1587
1588                 if (max_change < change)
1589                         max_change = change;
1590         }
1591         count = i; /* where we can stop scanning in data->files[] */
1592
1593         /*
1594          * We have width = stat_width or term_columns() columns total.
1595          * We want a maximum of min(max_len, stat_name_width) for the name part.
1596          * We want a maximum of min(max_change, stat_graph_width) for the +- part.
1597          * We also need 1 for " " and 4 + decimal_width(max_change)
1598          * for " | NNNN " and one the empty column at the end, altogether
1599          * 6 + decimal_width(max_change).
1600          *
1601          * If there's not enough space, we will use the smaller of
1602          * stat_name_width (if set) and 5/8*width for the filename,
1603          * and the rest for constant elements + graph part, but no more
1604          * than stat_graph_width for the graph part.
1605          * (5/8 gives 50 for filename and 30 for the constant parts + graph
1606          * for the standard terminal size).
1607          *
1608          * In other words: stat_width limits the maximum width, and
1609          * stat_name_width fixes the maximum width of the filename,
1610          * and is also used to divide available columns if there
1611          * aren't enough.
1612          *
1613          * Binary files are displayed with "Bin XXX -> YYY bytes"
1614          * instead of the change count and graph. This part is treated
1615          * similarly to the graph part, except that it is not
1616          * "scaled". If total width is too small to accommodate the
1617          * guaranteed minimum width of the filename part and the
1618          * separators and this message, this message will "overflow"
1619          * making the line longer than the maximum width.
1620          */
1621
1622         if (options->stat_width == -1)
1623                 width = term_columns() - options->output_prefix_length;
1624         else
1625                 width = options->stat_width ? options->stat_width : 80;
1626         number_width = decimal_width(max_change) > number_width ?
1627                 decimal_width(max_change) : number_width;
1628
1629         if (options->stat_graph_width == -1)
1630                 options->stat_graph_width = diff_stat_graph_width;
1631
1632         /*
1633          * Guarantee 3/8*16==6 for the graph part
1634          * and 5/8*16==10 for the filename part
1635          */
1636         if (width < 16 + 6 + number_width)
1637                 width = 16 + 6 + number_width;
1638
1639         /*
1640          * First assign sizes that are wanted, ignoring available width.
1641          * strlen("Bin XXX -> YYY bytes") == bin_width, and the part
1642          * starting from "XXX" should fit in graph_width.
1643          */
1644         graph_width = max_change + 4 > bin_width ? max_change : bin_width - 4;
1645         if (options->stat_graph_width &&
1646             options->stat_graph_width < graph_width)
1647                 graph_width = options->stat_graph_width;
1648
1649         name_width = (options->stat_name_width > 0 &&
1650                       options->stat_name_width < max_len) ?
1651                 options->stat_name_width : max_len;
1652
1653         /*
1654          * Adjust adjustable widths not to exceed maximum width
1655          */
1656         if (name_width + number_width + 6 + graph_width > width) {
1657                 if (graph_width > width * 3/8 - number_width - 6) {
1658                         graph_width = width * 3/8 - number_width - 6;
1659                         if (graph_width < 6)
1660                                 graph_width = 6;
1661                 }
1662
1663                 if (options->stat_graph_width &&
1664                     graph_width > options->stat_graph_width)
1665                         graph_width = options->stat_graph_width;
1666                 if (name_width > width - number_width - 6 - graph_width)
1667                         name_width = width - number_width - 6 - graph_width;
1668                 else
1669                         graph_width = width - number_width - 6 - name_width;
1670         }
1671
1672         /*
1673          * From here name_width is the width of the name area,
1674          * and graph_width is the width of the graph area.
1675          * max_change is used to scale graph properly.
1676          */
1677         for (i = 0; i < count; i++) {
1678                 const char *prefix = "";
1679                 struct diffstat_file *file = data->files[i];
1680                 char *name = file->print_name;
1681                 uintmax_t added = file->added;
1682                 uintmax_t deleted = file->deleted;
1683                 int name_len;
1684
1685                 if (!file->is_interesting && (added + deleted == 0))
1686                         continue;
1687
1688                 /*
1689                  * "scale" the filename
1690                  */
1691                 len = name_width;
1692                 name_len = strlen(name);
1693                 if (name_width < name_len) {
1694                         char *slash;
1695                         prefix = "...";
1696                         len -= 3;
1697                         name += name_len - len;
1698                         slash = strchr(name, '/');
1699                         if (slash)
1700                                 name = slash;
1701                 }
1702
1703                 if (file->is_binary) {
1704                         fprintf(options->file, "%s", line_prefix);
1705                         show_name(options->file, prefix, name, len);
1706                         fprintf(options->file, " %*s", number_width, "Bin");
1707                         if (!added && !deleted) {
1708                                 putc('\n', options->file);
1709                                 continue;
1710                         }
1711                         fprintf(options->file, " %s%"PRIuMAX"%s",
1712                                 del_c, deleted, reset);
1713                         fprintf(options->file, " -> ");
1714                         fprintf(options->file, "%s%"PRIuMAX"%s",
1715                                 add_c, added, reset);
1716                         fprintf(options->file, " bytes");
1717                         fprintf(options->file, "\n");
1718                         continue;
1719                 }
1720                 else if (file->is_unmerged) {
1721                         fprintf(options->file, "%s", line_prefix);
1722                         show_name(options->file, prefix, name, len);
1723                         fprintf(options->file, " Unmerged\n");
1724                         continue;
1725                 }
1726
1727                 /*
1728                  * scale the add/delete
1729                  */
1730                 add = added;
1731                 del = deleted;
1732
1733                 if (graph_width <= max_change) {
1734                         int total = scale_linear(add + del, graph_width, max_change);
1735                         if (total < 2 && add && del)
1736                                 /* width >= 2 due to the sanity check */
1737                                 total = 2;
1738                         if (add < del) {
1739                                 add = scale_linear(add, graph_width, max_change);
1740                                 del = total - add;
1741                         } else {
1742                                 del = scale_linear(del, graph_width, max_change);
1743                                 add = total - del;
1744                         }
1745                 }
1746                 fprintf(options->file, "%s", line_prefix);
1747                 show_name(options->file, prefix, name, len);
1748                 fprintf(options->file, " %*"PRIuMAX"%s",
1749                         number_width, added + deleted,
1750                         added + deleted ? " " : "");
1751                 show_graph(options->file, '+', add, add_c, reset);
1752                 show_graph(options->file, '-', del, del_c, reset);
1753                 fprintf(options->file, "\n");
1754         }
1755
1756         for (i = 0; i < data->nr; i++) {
1757                 struct diffstat_file *file = data->files[i];
1758                 uintmax_t added = file->added;
1759                 uintmax_t deleted = file->deleted;
1760
1761                 if (file->is_unmerged ||
1762                     (!file->is_interesting && (added + deleted == 0))) {
1763                         total_files--;
1764                         continue;
1765                 }
1766
1767                 if (!file->is_binary) {
1768                         adds += added;
1769                         dels += deleted;
1770                 }
1771                 if (i < count)
1772                         continue;
1773                 if (!extra_shown)
1774                         fprintf(options->file, "%s ...\n", line_prefix);
1775                 extra_shown = 1;
1776         }
1777         fprintf(options->file, "%s", line_prefix);
1778         print_stat_summary(options->file, total_files, adds, dels);
1779 }
1780
1781 static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
1782 {
1783         int i, adds = 0, dels = 0, total_files = data->nr;
1784
1785         if (data->nr == 0)
1786                 return;
1787
1788         for (i = 0; i < data->nr; i++) {
1789                 int added = data->files[i]->added;
1790                 int deleted= data->files[i]->deleted;
1791
1792                 if (data->files[i]->is_unmerged ||
1793                     (!data->files[i]->is_interesting && (added + deleted == 0))) {
1794                         total_files--;
1795                 } else if (!data->files[i]->is_binary) { /* don't count bytes */
1796                         adds += added;
1797                         dels += deleted;
1798                 }
1799         }
1800         fprintf(options->file, "%s", diff_line_prefix(options));
1801         print_stat_summary(options->file, total_files, adds, dels);
1802 }
1803
1804 static void show_numstat(struct diffstat_t *data, struct diff_options *options)
1805 {
1806         int i;
1807
1808         if (data->nr == 0)
1809                 return;
1810
1811         for (i = 0; i < data->nr; i++) {
1812                 struct diffstat_file *file = data->files[i];
1813
1814                 fprintf(options->file, "%s", diff_line_prefix(options));
1815
1816                 if (file->is_binary)
1817                         fprintf(options->file, "-\t-\t");
1818                 else
1819                         fprintf(options->file,
1820                                 "%"PRIuMAX"\t%"PRIuMAX"\t",
1821                                 file->added, file->deleted);
1822                 if (options->line_termination) {
1823                         fill_print_name(file);
1824                         if (!file->is_renamed)
1825                                 write_name_quoted(file->name, options->file,
1826                                                   options->line_termination);
1827                         else {
1828                                 fputs(file->print_name, options->file);
1829                                 putc(options->line_termination, options->file);
1830                         }
1831                 } else {
1832                         if (file->is_renamed) {
1833                                 putc('\0', options->file);
1834                                 write_name_quoted(file->from_name, options->file, '\0');
1835                         }
1836                         write_name_quoted(file->name, options->file, '\0');
1837                 }
1838         }
1839 }
1840
1841 struct dirstat_file {
1842         const char *name;
1843         unsigned long changed;
1844 };
1845
1846 struct dirstat_dir {
1847         struct dirstat_file *files;
1848         int alloc, nr, permille, cumulative;
1849 };
1850
1851 static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
1852                 unsigned long changed, const char *base, int baselen)
1853 {
1854         unsigned long this_dir = 0;
1855         unsigned int sources = 0;
1856         const char *line_prefix = diff_line_prefix(opt);
1857
1858         while (dir->nr) {
1859                 struct dirstat_file *f = dir->files;
1860                 int namelen = strlen(f->name);
1861                 unsigned long this;
1862                 char *slash;
1863
1864                 if (namelen < baselen)
1865                         break;
1866                 if (memcmp(f->name, base, baselen))
1867                         break;
1868                 slash = strchr(f->name + baselen, '/');
1869                 if (slash) {
1870                         int newbaselen = slash + 1 - f->name;
1871                         this = gather_dirstat(opt, dir, changed, f->name, newbaselen);
1872                         sources++;
1873                 } else {
1874                         this = f->changed;
1875                         dir->files++;
1876                         dir->nr--;
1877                         sources += 2;
1878                 }
1879                 this_dir += this;
1880         }
1881
1882         /*
1883          * We don't report dirstat's for
1884          *  - the top level
1885          *  - or cases where everything came from a single directory
1886          *    under this directory (sources == 1).
1887          */
1888         if (baselen && sources != 1) {
1889                 if (this_dir) {
1890                         int permille = this_dir * 1000 / changed;
1891                         if (permille >= dir->permille) {
1892                                 fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
1893                                         permille / 10, permille % 10, baselen, base);
1894                                 if (!dir->cumulative)
1895                                         return 0;
1896                         }
1897                 }
1898         }
1899         return this_dir;
1900 }
1901
1902 static int dirstat_compare(const void *_a, const void *_b)
1903 {
1904         const struct dirstat_file *a = _a;
1905         const struct dirstat_file *b = _b;
1906         return strcmp(a->name, b->name);
1907 }
1908
1909 static void show_dirstat(struct diff_options *options)
1910 {
1911         int i;
1912         unsigned long changed;
1913         struct dirstat_dir dir;
1914         struct diff_queue_struct *q = &diff_queued_diff;
1915
1916         dir.files = NULL;
1917         dir.alloc = 0;
1918         dir.nr = 0;
1919         dir.permille = options->dirstat_permille;
1920         dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1921
1922         changed = 0;
1923         for (i = 0; i < q->nr; i++) {
1924                 struct diff_filepair *p = q->queue[i];
1925                 const char *name;
1926                 unsigned long copied, added, damage;
1927                 int content_changed;
1928
1929                 name = p->two->path ? p->two->path : p->one->path;
1930
1931                 if (p->one->sha1_valid && p->two->sha1_valid)
1932                         content_changed = hashcmp(p->one->sha1, p->two->sha1);
1933                 else
1934                         content_changed = 1;
1935
1936                 if (!content_changed) {
1937                         /*
1938                          * The SHA1 has not changed, so pre-/post-content is
1939                          * identical. We can therefore skip looking at the
1940                          * file contents altogether.
1941                          */
1942                         damage = 0;
1943                         goto found_damage;
1944                 }
1945
1946                 if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE)) {
1947                         /*
1948                          * In --dirstat-by-file mode, we don't really need to
1949                          * look at the actual file contents at all.
1950                          * The fact that the SHA1 changed is enough for us to
1951                          * add this file to the list of results
1952                          * (with each file contributing equal damage).
1953                          */
1954                         damage = 1;
1955                         goto found_damage;
1956                 }
1957
1958                 if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
1959                         diff_populate_filespec(p->one, 0);
1960                         diff_populate_filespec(p->two, 0);
1961                         diffcore_count_changes(p->one, p->two, NULL, NULL, 0,
1962                                                &copied, &added);
1963                         diff_free_filespec_data(p->one);
1964                         diff_free_filespec_data(p->two);
1965                 } else if (DIFF_FILE_VALID(p->one)) {
1966                         diff_populate_filespec(p->one, CHECK_SIZE_ONLY);
1967                         copied = added = 0;
1968                         diff_free_filespec_data(p->one);
1969                 } else if (DIFF_FILE_VALID(p->two)) {
1970                         diff_populate_filespec(p->two, CHECK_SIZE_ONLY);
1971                         copied = 0;
1972                         added = p->two->size;
1973                         diff_free_filespec_data(p->two);
1974                 } else
1975                         continue;
1976
1977                 /*
1978                  * Original minus copied is the removed material,
1979                  * added is the new material.  They are both damages
1980                  * made to the preimage.
1981                  * If the resulting damage is zero, we know that
1982                  * diffcore_count_changes() considers the two entries to
1983                  * be identical, but since content_changed is true, we
1984                  * know that there must have been _some_ kind of change,
1985                  * so we force all entries to have damage > 0.
1986                  */
1987                 damage = (p->one->size - copied) + added;
1988                 if (!damage)
1989                         damage = 1;
1990
1991 found_damage:
1992                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1993                 dir.files[dir.nr].name = name;
1994                 dir.files[dir.nr].changed = damage;
1995                 changed += damage;
1996                 dir.nr++;
1997         }
1998
1999         /* This can happen even with many files, if everything was renames */
2000         if (!changed)
2001                 return;
2002
2003         /* Show all directories with more than x% of the changes */
2004         qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
2005         gather_dirstat(options, &dir, changed, "", 0);
2006 }
2007
2008 static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
2009 {
2010         int i;
2011         unsigned long changed;
2012         struct dirstat_dir dir;
2013
2014         if (data->nr == 0)
2015                 return;
2016
2017         dir.files = NULL;
2018         dir.alloc = 0;
2019         dir.nr = 0;
2020         dir.permille = options->dirstat_permille;
2021         dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
2022
2023         changed = 0;
2024         for (i = 0; i < data->nr; i++) {
2025                 struct diffstat_file *file = data->files[i];
2026                 unsigned long damage = file->added + file->deleted;
2027                 if (file->is_binary)
2028                         /*
2029                          * binary files counts bytes, not lines. Must find some
2030                          * way to normalize binary bytes vs. textual lines.
2031                          * The following heuristic assumes that there are 64
2032                          * bytes per "line".
2033                          * This is stupid and ugly, but very cheap...
2034                          */
2035                         damage = (damage + 63) / 64;
2036                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
2037                 dir.files[dir.nr].name = file->name;
2038                 dir.files[dir.nr].changed = damage;
2039                 changed += damage;
2040                 dir.nr++;
2041         }
2042
2043         /* This can happen even with many files, if everything was renames */
2044         if (!changed)
2045                 return;
2046
2047         /* Show all directories with more than x% of the changes */
2048         qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
2049         gather_dirstat(options, &dir, changed, "", 0);
2050 }
2051
2052 static void free_diffstat_info(struct diffstat_t *diffstat)
2053 {
2054         int i;
2055         for (i = 0; i < diffstat->nr; i++) {
2056                 struct diffstat_file *f = diffstat->files[i];
2057                 if (f->name != f->print_name)
2058                         free(f->print_name);
2059                 free(f->name);
2060                 free(f->from_name);
2061                 free(f);
2062         }
2063         free(diffstat->files);
2064 }
2065
2066 struct checkdiff_t {
2067         const char *filename;
2068         int lineno;
2069         int conflict_marker_size;
2070         struct diff_options *o;
2071         unsigned ws_rule;
2072         unsigned status;
2073 };
2074
2075 static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
2076 {
2077         char firstchar;
2078         int cnt;
2079
2080         if (len < marker_size + 1)
2081                 return 0;
2082         firstchar = line[0];
2083         switch (firstchar) {
2084         case '=': case '>': case '<': case '|':
2085                 break;
2086         default:
2087                 return 0;
2088         }
2089         for (cnt = 1; cnt < marker_size; cnt++)
2090                 if (line[cnt] != firstchar)
2091                         return 0;
2092         /* line[1] thru line[marker_size-1] are same as firstchar */
2093         if (len < marker_size + 1 || !isspace(line[marker_size]))
2094                 return 0;
2095         return 1;
2096 }
2097
2098 static void checkdiff_consume(void *priv, char *line, unsigned long len)
2099 {
2100         struct checkdiff_t *data = priv;
2101         int marker_size = data->conflict_marker_size;
2102         const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
2103         const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
2104         const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
2105         char *err;
2106         const char *line_prefix;
2107
2108         assert(data->o);
2109         line_prefix = diff_line_prefix(data->o);
2110
2111         if (line[0] == '+') {
2112                 unsigned bad;
2113                 data->lineno++;
2114                 if (is_conflict_marker(line + 1, marker_size, len - 1)) {
2115                         data->status |= 1;
2116                         fprintf(data->o->file,
2117                                 "%s%s:%d: leftover conflict marker\n",
2118                                 line_prefix, data->filename, data->lineno);
2119                 }
2120                 bad = ws_check(line + 1, len - 1, data->ws_rule);
2121                 if (!bad)
2122                         return;
2123                 data->status |= bad;
2124                 err = whitespace_error_string(bad);
2125                 fprintf(data->o->file, "%s%s:%d: %s.\n",
2126                         line_prefix, data->filename, data->lineno, err);
2127                 free(err);
2128                 emit_line(data->o, set, reset, line, 1);
2129                 ws_check_emit(line + 1, len - 1, data->ws_rule,
2130                               data->o->file, set, reset, ws);
2131         } else if (line[0] == ' ') {
2132                 data->lineno++;
2133         } else if (line[0] == '@') {
2134                 char *plus = strchr(line, '+');
2135                 if (plus)
2136                         data->lineno = strtol(plus, NULL, 10) - 1;
2137                 else
2138                         die("invalid diff");
2139         }
2140 }
2141
2142 static unsigned char *deflate_it(char *data,
2143                                  unsigned long size,
2144                                  unsigned long *result_size)
2145 {
2146         int bound;
2147         unsigned char *deflated;
2148         git_zstream stream;
2149
2150         git_deflate_init(&stream, zlib_compression_level);
2151         bound = git_deflate_bound(&stream, size);
2152         deflated = xmalloc(bound);
2153         stream.next_out = deflated;
2154         stream.avail_out = bound;
2155
2156         stream.next_in = (unsigned char *)data;
2157         stream.avail_in = size;
2158         while (git_deflate(&stream, Z_FINISH) == Z_OK)
2159                 ; /* nothing */
2160         git_deflate_end(&stream);
2161         *result_size = stream.total_out;
2162         return deflated;
2163 }
2164
2165 static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two,
2166                                   const char *prefix)
2167 {
2168         void *cp;
2169         void *delta;
2170         void *deflated;
2171         void *data;
2172         unsigned long orig_size;
2173         unsigned long delta_size;
2174         unsigned long deflate_size;
2175         unsigned long data_size;
2176
2177         /* We could do deflated delta, or we could do just deflated two,
2178          * whichever is smaller.
2179          */
2180         delta = NULL;
2181         deflated = deflate_it(two->ptr, two->size, &deflate_size);
2182         if (one->size && two->size) {
2183                 delta = diff_delta(one->ptr, one->size,
2184                                    two->ptr, two->size,
2185                                    &delta_size, deflate_size);
2186                 if (delta) {
2187                         void *to_free = delta;
2188                         orig_size = delta_size;
2189                         delta = deflate_it(delta, delta_size, &delta_size);
2190                         free(to_free);
2191                 }
2192         }
2193
2194         if (delta && delta_size < deflate_size) {
2195                 fprintf(file, "%sdelta %lu\n", prefix, orig_size);
2196                 free(deflated);
2197                 data = delta;
2198                 data_size = delta_size;
2199         }
2200         else {
2201                 fprintf(file, "%sliteral %lu\n", prefix, two->size);
2202                 free(delta);
2203                 data = deflated;
2204                 data_size = deflate_size;
2205         }
2206
2207         /* emit data encoded in base85 */
2208         cp = data;
2209         while (data_size) {
2210                 int bytes = (52 < data_size) ? 52 : data_size;
2211                 char line[70];
2212                 data_size -= bytes;
2213                 if (bytes <= 26)
2214                         line[0] = bytes + 'A' - 1;
2215                 else
2216                         line[0] = bytes - 26 + 'a' - 1;
2217                 encode_85(line + 1, cp, bytes);
2218                 cp = (char *) cp + bytes;
2219                 fprintf(file, "%s", prefix);
2220                 fputs(line, file);
2221                 fputc('\n', file);
2222         }
2223         fprintf(file, "%s\n", prefix);
2224         free(data);
2225 }
2226
2227 static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two,
2228                              const char *prefix)
2229 {
2230         fprintf(file, "%sGIT binary patch\n", prefix);
2231         emit_binary_diff_body(file, one, two, prefix);
2232         emit_binary_diff_body(file, two, one, prefix);
2233 }
2234
2235 int diff_filespec_is_binary(struct diff_filespec *one)
2236 {
2237         if (one->is_binary == -1) {
2238                 diff_filespec_load_driver(one);
2239                 if (one->driver->binary != -1)
2240                         one->is_binary = one->driver->binary;
2241                 else {
2242                         if (!one->data && DIFF_FILE_VALID(one))
2243                                 diff_populate_filespec(one, CHECK_BINARY);
2244                         if (one->is_binary == -1 && one->data)
2245                                 one->is_binary = buffer_is_binary(one->data,
2246                                                 one->size);
2247                         if (one->is_binary == -1)
2248                                 one->is_binary = 0;
2249                 }
2250         }
2251         return one->is_binary;
2252 }
2253
2254 static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
2255 {
2256         diff_filespec_load_driver(one);
2257         return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
2258 }
2259
2260 void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
2261 {
2262         if (!options->a_prefix)
2263                 options->a_prefix = a;
2264         if (!options->b_prefix)
2265                 options->b_prefix = b;
2266 }
2267
2268 struct userdiff_driver *get_textconv(struct diff_filespec *one)
2269 {
2270         if (!DIFF_FILE_VALID(one))
2271                 return NULL;
2272
2273         diff_filespec_load_driver(one);
2274         return userdiff_get_textconv(one->driver);
2275 }
2276
2277 static void builtin_diff(const char *name_a,
2278                          const char *name_b,
2279                          struct diff_filespec *one,
2280                          struct diff_filespec *two,
2281                          const char *xfrm_msg,
2282                          int must_show_header,
2283                          struct diff_options *o,
2284                          int complete_rewrite)
2285 {
2286         mmfile_t mf1, mf2;
2287         const char *lbl[2];
2288         char *a_one, *b_two;
2289         const char *meta = diff_get_color_opt(o, DIFF_METAINFO);
2290         const char *reset = diff_get_color_opt(o, DIFF_RESET);
2291         const char *a_prefix, *b_prefix;
2292         struct userdiff_driver *textconv_one = NULL;
2293         struct userdiff_driver *textconv_two = NULL;
2294         struct strbuf header = STRBUF_INIT;
2295         const char *line_prefix = diff_line_prefix(o);
2296
2297         if (DIFF_OPT_TST(o, SUBMODULE_LOG) &&
2298                         (!one->mode || S_ISGITLINK(one->mode)) &&
2299                         (!two->mode || S_ISGITLINK(two->mode))) {
2300                 const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
2301                 const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
2302                 show_submodule_summary(o->file, one->path ? one->path : two->path,
2303                                 line_prefix,
2304                                 one->sha1, two->sha1, two->dirty_submodule,
2305                                 meta, del, add, reset);
2306                 return;
2307         }
2308
2309         if (DIFF_OPT_TST(o, ALLOW_TEXTCONV)) {
2310                 textconv_one = get_textconv(one);
2311                 textconv_two = get_textconv(two);
2312         }
2313
2314         diff_set_mnemonic_prefix(o, "a/", "b/");
2315         if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
2316                 a_prefix = o->b_prefix;
2317                 b_prefix = o->a_prefix;
2318         } else {
2319                 a_prefix = o->a_prefix;
2320                 b_prefix = o->b_prefix;
2321         }
2322
2323         /* Never use a non-valid filename anywhere if at all possible */
2324         name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
2325         name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
2326
2327         a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
2328         b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
2329         lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
2330         lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
2331         strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, meta, a_one, b_two, reset);
2332         if (lbl[0][0] == '/') {
2333                 /* /dev/null */
2334                 strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, meta, two->mode, reset);
2335                 if (xfrm_msg)
2336                         strbuf_addstr(&header, xfrm_msg);
2337                 must_show_header = 1;
2338         }
2339         else if (lbl[1][0] == '/') {
2340                 strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, meta, one->mode, reset);
2341                 if (xfrm_msg)
2342                         strbuf_addstr(&header, xfrm_msg);
2343                 must_show_header = 1;
2344         }
2345         else {
2346                 if (one->mode != two->mode) {
2347                         strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, meta, one->mode, reset);
2348                         strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, meta, two->mode, reset);
2349                         must_show_header = 1;
2350                 }
2351                 if (xfrm_msg)
2352                         strbuf_addstr(&header, xfrm_msg);
2353
2354                 /*
2355                  * we do not run diff between different kind
2356                  * of objects.
2357                  */
2358                 if ((one->mode ^ two->mode) & S_IFMT)
2359                         goto free_ab_and_return;
2360                 if (complete_rewrite &&
2361                     (textconv_one || !diff_filespec_is_binary(one)) &&
2362                     (textconv_two || !diff_filespec_is_binary(two))) {
2363                         fprintf(o->file, "%s", header.buf);
2364                         strbuf_reset(&header);
2365                         emit_rewrite_diff(name_a, name_b, one, two,
2366                                                 textconv_one, textconv_two, o);
2367                         o->found_changes = 1;
2368                         goto free_ab_and_return;
2369                 }
2370         }
2371
2372         if (o->irreversible_delete && lbl[1][0] == '/') {
2373                 fprintf(o->file, "%s", header.buf);
2374                 strbuf_reset(&header);
2375                 goto free_ab_and_return;
2376         } else if (!DIFF_OPT_TST(o, TEXT) &&
2377             ( (!textconv_one && diff_filespec_is_binary(one)) ||
2378               (!textconv_two && diff_filespec_is_binary(two)) )) {
2379                 if (!one->data && !two->data &&
2380                     S_ISREG(one->mode) && S_ISREG(two->mode) &&
2381                     !DIFF_OPT_TST(o, BINARY)) {
2382                         if (!hashcmp(one->sha1, two->sha1)) {
2383                                 if (must_show_header)
2384                                         fprintf(o->file, "%s", header.buf);
2385                                 goto free_ab_and_return;
2386                         }
2387                         fprintf(o->file, "%s", header.buf);
2388                         fprintf(o->file, "%sBinary files %s and %s differ\n",
2389                                 line_prefix, lbl[0], lbl[1]);
2390                         goto free_ab_and_return;
2391                 }
2392                 if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2393                         die("unable to read files to diff");
2394                 /* Quite common confusing case */
2395                 if (mf1.size == mf2.size &&
2396                     !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
2397                         if (must_show_header)
2398                                 fprintf(o->file, "%s", header.buf);
2399                         goto free_ab_and_return;
2400                 }
2401                 fprintf(o->file, "%s", header.buf);
2402                 strbuf_reset(&header);
2403                 if (DIFF_OPT_TST(o, BINARY))
2404                         emit_binary_diff(o->file, &mf1, &mf2, line_prefix);
2405                 else
2406                         fprintf(o->file, "%sBinary files %s and %s differ\n",
2407                                 line_prefix, lbl[0], lbl[1]);
2408                 o->found_changes = 1;
2409         } else {
2410                 /* Crazy xdl interfaces.. */
2411                 const char *diffopts = getenv("GIT_DIFF_OPTS");
2412                 const char *v;
2413                 xpparam_t xpp;
2414                 xdemitconf_t xecfg;
2415                 struct emit_callback ecbdata;
2416                 const struct userdiff_funcname *pe;
2417
2418                 if (must_show_header) {
2419                         fprintf(o->file, "%s", header.buf);
2420                         strbuf_reset(&header);
2421                 }
2422
2423                 mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
2424                 mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
2425
2426                 pe = diff_funcname_pattern(one);
2427                 if (!pe)
2428                         pe = diff_funcname_pattern(two);
2429
2430                 memset(&xpp, 0, sizeof(xpp));
2431                 memset(&xecfg, 0, sizeof(xecfg));
2432                 memset(&ecbdata, 0, sizeof(ecbdata));
2433                 ecbdata.label_path = lbl;
2434                 ecbdata.color_diff = want_color(o->use_color);
2435                 ecbdata.found_changesp = &o->found_changes;
2436                 ecbdata.ws_rule = whitespace_rule(name_b);
2437                 if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
2438                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
2439                 ecbdata.opt = o;
2440                 ecbdata.header = header.len ? &header : NULL;
2441                 xpp.flags = o->xdl_opts;
2442                 xecfg.ctxlen = o->context;
2443                 xecfg.interhunkctxlen = o->interhunkcontext;
2444                 xecfg.flags = XDL_EMIT_FUNCNAMES;
2445                 if (DIFF_OPT_TST(o, FUNCCONTEXT))
2446                         xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
2447                 if (pe)
2448                         xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
2449                 if (!diffopts)
2450                         ;
2451                 else if (skip_prefix(diffopts, "--unified=", &v))
2452                         xecfg.ctxlen = strtoul(v, NULL, 10);
2453                 else if (skip_prefix(diffopts, "-u", &v))
2454                         xecfg.ctxlen = strtoul(v, NULL, 10);
2455                 if (o->word_diff)
2456                         init_diff_words_data(&ecbdata, o, one, two);
2457                 if (xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
2458                                   &xpp, &xecfg))
2459                         die("unable to generate diff for %s", one->path);
2460                 if (o->word_diff)
2461                         free_diff_words_data(&ecbdata);
2462                 if (textconv_one)
2463                         free(mf1.ptr);
2464                 if (textconv_two)
2465                         free(mf2.ptr);
2466                 xdiff_clear_find_func(&xecfg);
2467         }
2468
2469  free_ab_and_return:
2470         strbuf_release(&header);
2471         diff_free_filespec_data(one);
2472         diff_free_filespec_data(two);
2473         free(a_one);
2474         free(b_two);
2475         return;
2476 }
2477
2478 static void builtin_diffstat(const char *name_a, const char *name_b,
2479                              struct diff_filespec *one,
2480                              struct diff_filespec *two,
2481                              struct diffstat_t *diffstat,
2482                              struct diff_options *o,
2483                              struct diff_filepair *p)
2484 {
2485         mmfile_t mf1, mf2;
2486         struct diffstat_file *data;
2487         int same_contents;
2488         int complete_rewrite = 0;
2489
2490         if (!DIFF_PAIR_UNMERGED(p)) {
2491                 if (p->status == DIFF_STATUS_MODIFIED && p->score)
2492                         complete_rewrite = 1;
2493         }
2494
2495         data = diffstat_add(diffstat, name_a, name_b);
2496         data->is_interesting = p->status != DIFF_STATUS_UNKNOWN;
2497
2498         if (!one || !two) {
2499                 data->is_unmerged = 1;
2500                 return;
2501         }
2502
2503         same_contents = !hashcmp(one->sha1, two->sha1);
2504
2505         if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
2506                 data->is_binary = 1;
2507                 if (same_contents) {
2508                         data->added = 0;
2509                         data->deleted = 0;
2510                 } else {
2511                         data->added = diff_filespec_size(two);
2512                         data->deleted = diff_filespec_size(one);
2513                 }
2514         }
2515
2516         else if (complete_rewrite) {
2517                 diff_populate_filespec(one, 0);
2518                 diff_populate_filespec(two, 0);
2519                 data->deleted = count_lines(one->data, one->size);
2520                 data->added = count_lines(two->data, two->size);
2521         }
2522
2523         else if (!same_contents) {
2524                 /* Crazy xdl interfaces.. */
2525                 xpparam_t xpp;
2526                 xdemitconf_t xecfg;
2527
2528                 if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2529                         die("unable to read files to diff");
2530
2531                 memset(&xpp, 0, sizeof(xpp));
2532                 memset(&xecfg, 0, sizeof(xecfg));
2533                 xpp.flags = o->xdl_opts;
2534                 xecfg.ctxlen = o->context;
2535                 xecfg.interhunkctxlen = o->interhunkcontext;
2536                 if (xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
2537                                   &xpp, &xecfg))
2538                         die("unable to generate diffstat for %s", one->path);
2539         }
2540
2541         diff_free_filespec_data(one);
2542         diff_free_filespec_data(two);
2543 }
2544
2545 static void builtin_checkdiff(const char *name_a, const char *name_b,
2546                               const char *attr_path,
2547                               struct diff_filespec *one,
2548                               struct diff_filespec *two,
2549                               struct diff_options *o)
2550 {
2551         mmfile_t mf1, mf2;
2552         struct checkdiff_t data;
2553
2554         if (!two)
2555                 return;
2556
2557         memset(&data, 0, sizeof(data));
2558         data.filename = name_b ? name_b : name_a;
2559         data.lineno = 0;
2560         data.o = o;
2561         data.ws_rule = whitespace_rule(attr_path);
2562         data.conflict_marker_size = ll_merge_marker_size(attr_path);
2563
2564         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2565                 die("unable to read files to diff");
2566
2567         /*
2568          * All the other codepaths check both sides, but not checking
2569          * the "old" side here is deliberate.  We are checking the newly
2570          * introduced changes, and as long as the "new" side is text, we
2571          * can and should check what it introduces.
2572          */
2573         if (diff_filespec_is_binary(two))
2574                 goto free_and_return;
2575         else {
2576                 /* Crazy xdl interfaces.. */
2577                 xpparam_t xpp;
2578                 xdemitconf_t xecfg;
2579
2580                 memset(&xpp, 0, sizeof(xpp));
2581                 memset(&xecfg, 0, sizeof(xecfg));
2582                 xecfg.ctxlen = 1; /* at least one context line */
2583                 xpp.flags = 0;
2584                 if (xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
2585                                   &xpp, &xecfg))
2586                         die("unable to generate checkdiff for %s", one->path);
2587
2588                 if (data.ws_rule & WS_BLANK_AT_EOF) {
2589                         struct emit_callback ecbdata;
2590                         int blank_at_eof;
2591
2592                         ecbdata.ws_rule = data.ws_rule;
2593                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
2594                         blank_at_eof = ecbdata.blank_at_eof_in_postimage;
2595
2596                         if (blank_at_eof) {
2597                                 static char *err;
2598                                 if (!err)
2599                                         err = whitespace_error_string(WS_BLANK_AT_EOF);
2600                                 fprintf(o->file, "%s:%d: %s.\n",
2601                                         data.filename, blank_at_eof, err);
2602                                 data.status = 1; /* report errors */
2603                         }
2604                 }
2605         }
2606  free_and_return:
2607         diff_free_filespec_data(one);
2608         diff_free_filespec_data(two);
2609         if (data.status)
2610                 DIFF_OPT_SET(o, CHECK_FAILED);
2611 }
2612
2613 struct diff_filespec *alloc_filespec(const char *path)
2614 {
2615         int namelen = strlen(path);
2616         struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
2617
2618         memset(spec, 0, sizeof(*spec));
2619         spec->path = (char *)(spec + 1);
2620         memcpy(spec->path, path, namelen+1);
2621         spec->count = 1;
2622         spec->is_binary = -1;
2623         return spec;
2624 }
2625
2626 void free_filespec(struct diff_filespec *spec)
2627 {
2628         if (!--spec->count) {
2629                 diff_free_filespec_data(spec);
2630                 free(spec);
2631         }
2632 }
2633
2634 void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
2635                    int sha1_valid, unsigned short mode)
2636 {
2637         if (mode) {
2638                 spec->mode = canon_mode(mode);
2639                 hashcpy(spec->sha1, sha1);
2640                 spec->sha1_valid = sha1_valid;
2641         }
2642 }
2643
2644 /*
2645  * Given a name and sha1 pair, if the index tells us the file in
2646  * the work tree has that object contents, return true, so that
2647  * prepare_temp_file() does not have to inflate and extract.
2648  */
2649 static int reuse_worktree_file(const char *name, const unsigned char *sha1, int want_file)
2650 {
2651         const struct cache_entry *ce;
2652         struct stat st;
2653         int pos, len;
2654
2655         /*
2656          * We do not read the cache ourselves here, because the
2657          * benchmark with my previous version that always reads cache
2658          * shows that it makes things worse for diff-tree comparing
2659          * two linux-2.6 kernel trees in an already checked out work
2660          * tree.  This is because most diff-tree comparisons deal with
2661          * only a small number of files, while reading the cache is
2662          * expensive for a large project, and its cost outweighs the
2663          * savings we get by not inflating the object to a temporary
2664          * file.  Practically, this code only helps when we are used
2665          * by diff-cache --cached, which does read the cache before
2666          * calling us.
2667          */
2668         if (!active_cache)
2669                 return 0;
2670
2671         /* We want to avoid the working directory if our caller
2672          * doesn't need the data in a normal file, this system
2673          * is rather slow with its stat/open/mmap/close syscalls,
2674          * and the object is contained in a pack file.  The pack
2675          * is probably already open and will be faster to obtain
2676          * the data through than the working directory.  Loose
2677          * objects however would tend to be slower as they need
2678          * to be individually opened and inflated.
2679          */
2680         if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(sha1))
2681                 return 0;
2682
2683         len = strlen(name);
2684         pos = cache_name_pos(name, len);
2685         if (pos < 0)
2686                 return 0;
2687         ce = active_cache[pos];
2688
2689         /*
2690          * This is not the sha1 we are looking for, or
2691          * unreusable because it is not a regular file.
2692          */
2693         if (hashcmp(sha1, ce->sha1) || !S_ISREG(ce->ce_mode))
2694                 return 0;
2695
2696         /*
2697          * If ce is marked as "assume unchanged", there is no
2698          * guarantee that work tree matches what we are looking for.
2699          */
2700         if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
2701                 return 0;
2702
2703         /*
2704          * If ce matches the file in the work tree, we can reuse it.
2705          */
2706         if (ce_uptodate(ce) ||
2707             (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
2708                 return 1;
2709
2710         return 0;
2711 }
2712
2713 static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
2714 {
2715         int len;
2716         char *data = xmalloc(100), *dirty = "";
2717
2718         /* Are we looking at the work tree? */
2719         if (s->dirty_submodule)
2720                 dirty = "-dirty";
2721
2722         len = snprintf(data, 100,
2723                        "Subproject commit %s%s\n", sha1_to_hex(s->sha1), dirty);
2724         s->data = data;
2725         s->size = len;
2726         s->should_free = 1;
2727         if (size_only) {
2728                 s->data = NULL;
2729                 free(data);
2730         }
2731         return 0;
2732 }
2733
2734 /*
2735  * While doing rename detection and pickaxe operation, we may need to
2736  * grab the data for the blob (or file) for our own in-core comparison.
2737  * diff_filespec has data and size fields for this purpose.
2738  */
2739 int diff_populate_filespec(struct diff_filespec *s, unsigned int flags)
2740 {
2741         int size_only = flags & CHECK_SIZE_ONLY;
2742         int err = 0;
2743         /*
2744          * demote FAIL to WARN to allow inspecting the situation
2745          * instead of refusing.
2746          */
2747         enum safe_crlf crlf_warn = (safe_crlf == SAFE_CRLF_FAIL
2748                                     ? SAFE_CRLF_WARN
2749                                     : safe_crlf);
2750
2751         if (!DIFF_FILE_VALID(s))
2752                 die("internal error: asking to populate invalid file.");
2753         if (S_ISDIR(s->mode))
2754                 return -1;
2755
2756         if (s->data)
2757                 return 0;
2758
2759         if (size_only && 0 < s->size)
2760                 return 0;
2761
2762         if (S_ISGITLINK(s->mode))
2763                 return diff_populate_gitlink(s, size_only);
2764
2765         if (!s->sha1_valid ||
2766             reuse_worktree_file(s->path, s->sha1, 0)) {
2767                 struct strbuf buf = STRBUF_INIT;
2768                 struct stat st;
2769                 int fd;
2770
2771                 if (lstat(s->path, &st) < 0) {
2772                         if (errno == ENOENT) {
2773                         err_empty:
2774                                 err = -1;
2775                         empty:
2776                                 s->data = (char *)"";
2777                                 s->size = 0;
2778                                 return err;
2779                         }
2780                 }
2781                 s->size = xsize_t(st.st_size);
2782                 if (!s->size)
2783                         goto empty;
2784                 if (S_ISLNK(st.st_mode)) {
2785                         struct strbuf sb = STRBUF_INIT;
2786
2787                         if (strbuf_readlink(&sb, s->path, s->size))
2788                                 goto err_empty;
2789                         s->size = sb.len;
2790                         s->data = strbuf_detach(&sb, NULL);
2791                         s->should_free = 1;
2792                         return 0;
2793                 }
2794                 if (size_only)
2795                         return 0;
2796                 if ((flags & CHECK_BINARY) &&
2797                     s->size > big_file_threshold && s->is_binary == -1) {
2798                         s->is_binary = 1;
2799                         return 0;
2800                 }
2801                 fd = open(s->path, O_RDONLY);
2802                 if (fd < 0)
2803                         goto err_empty;
2804                 s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
2805                 close(fd);
2806                 s->should_munmap = 1;
2807
2808                 /*
2809                  * Convert from working tree format to canonical git format
2810                  */
2811                 if (convert_to_git(s->path, s->data, s->size, &buf, crlf_warn)) {
2812                         size_t size = 0;
2813                         munmap(s->data, s->size);
2814                         s->should_munmap = 0;
2815                         s->data = strbuf_detach(&buf, &size);
2816                         s->size = size;
2817                         s->should_free = 1;
2818                 }
2819         }
2820         else {
2821                 enum object_type type;
2822                 if (size_only || (flags & CHECK_BINARY)) {
2823                         type = sha1_object_info(s->sha1, &s->size);
2824                         if (type < 0)
2825                                 die("unable to read %s", sha1_to_hex(s->sha1));
2826                         if (size_only)
2827                                 return 0;
2828                         if (s->size > big_file_threshold && s->is_binary == -1) {
2829                                 s->is_binary = 1;
2830                                 return 0;
2831                         }
2832                 }
2833                 s->data = read_sha1_file(s->sha1, &type, &s->size);
2834                 if (!s->data)
2835                         die("unable to read %s", sha1_to_hex(s->sha1));
2836                 s->should_free = 1;
2837         }
2838         return 0;
2839 }
2840
2841 void diff_free_filespec_blob(struct diff_filespec *s)
2842 {
2843         if (s->should_free)
2844                 free(s->data);
2845         else if (s->should_munmap)
2846                 munmap(s->data, s->size);
2847
2848         if (s->should_free || s->should_munmap) {
2849                 s->should_free = s->should_munmap = 0;
2850                 s->data = NULL;
2851         }
2852 }
2853
2854 void diff_free_filespec_data(struct diff_filespec *s)
2855 {
2856         diff_free_filespec_blob(s);
2857         free(s->cnt_data);
2858         s->cnt_data = NULL;
2859 }
2860
2861 static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
2862                            void *blob,
2863                            unsigned long size,
2864                            const unsigned char *sha1,
2865                            int mode)
2866 {
2867         int fd;
2868         struct strbuf buf = STRBUF_INIT;
2869         struct strbuf template = STRBUF_INIT;
2870         char *path_dup = xstrdup(path);
2871         const char *base = basename(path_dup);
2872
2873         /* Generate "XXXXXX_basename.ext" */
2874         strbuf_addstr(&template, "XXXXXX_");
2875         strbuf_addstr(&template, base);
2876
2877         fd = mks_tempfile_ts(&temp->tempfile, template.buf, strlen(base) + 1);
2878         if (fd < 0)
2879                 die_errno("unable to create temp-file");
2880         if (convert_to_working_tree(path,
2881                         (const char *)blob, (size_t)size, &buf)) {
2882                 blob = buf.buf;
2883                 size = buf.len;
2884         }
2885         if (write_in_full(fd, blob, size) != size)
2886                 die_errno("unable to write temp-file");
2887         close_tempfile(&temp->tempfile);
2888         temp->name = get_tempfile_path(&temp->tempfile);
2889         sha1_to_hex_r(temp->hex, sha1);
2890         xsnprintf(temp->mode, sizeof(temp->mode), "%06o", mode);
2891         strbuf_release(&buf);
2892         strbuf_release(&template);
2893         free(path_dup);
2894 }
2895
2896 static struct diff_tempfile *prepare_temp_file(const char *name,
2897                 struct diff_filespec *one)
2898 {
2899         struct diff_tempfile *temp = claim_diff_tempfile();
2900
2901         if (!DIFF_FILE_VALID(one)) {
2902         not_a_valid_file:
2903                 /* A '-' entry produces this for file-2, and
2904                  * a '+' entry produces this for file-1.
2905                  */
2906                 temp->name = "/dev/null";
2907                 xsnprintf(temp->hex, sizeof(temp->hex), ".");
2908                 xsnprintf(temp->mode, sizeof(temp->mode), ".");
2909                 return temp;
2910         }
2911
2912         if (!S_ISGITLINK(one->mode) &&
2913             (!one->sha1_valid ||
2914              reuse_worktree_file(name, one->sha1, 1))) {
2915                 struct stat st;
2916                 if (lstat(name, &st) < 0) {
2917                         if (errno == ENOENT)
2918                                 goto not_a_valid_file;
2919                         die_errno("stat(%s)", name);
2920                 }
2921                 if (S_ISLNK(st.st_mode)) {
2922                         struct strbuf sb = STRBUF_INIT;
2923                         if (strbuf_readlink(&sb, name, st.st_size) < 0)
2924                                 die_errno("readlink(%s)", name);
2925                         prep_temp_blob(name, temp, sb.buf, sb.len,
2926                                        (one->sha1_valid ?
2927                                         one->sha1 : null_sha1),
2928                                        (one->sha1_valid ?
2929                                         one->mode : S_IFLNK));
2930                         strbuf_release(&sb);
2931                 }
2932                 else {
2933                         /* we can borrow from the file in the work tree */
2934                         temp->name = name;
2935                         if (!one->sha1_valid)
2936                                 sha1_to_hex_r(temp->hex, null_sha1);
2937                         else
2938                                 sha1_to_hex_r(temp->hex, one->sha1);
2939                         /* Even though we may sometimes borrow the
2940                          * contents from the work tree, we always want
2941                          * one->mode.  mode is trustworthy even when
2942                          * !(one->sha1_valid), as long as
2943                          * DIFF_FILE_VALID(one).
2944                          */
2945                         xsnprintf(temp->mode, sizeof(temp->mode), "%06o", one->mode);
2946                 }
2947                 return temp;
2948         }
2949         else {
2950                 if (diff_populate_filespec(one, 0))
2951                         die("cannot read data blob for %s", one->path);
2952                 prep_temp_blob(name, temp, one->data, one->size,
2953                                one->sha1, one->mode);
2954         }
2955         return temp;
2956 }
2957
2958 static void add_external_diff_name(struct argv_array *argv,
2959                                    const char *name,
2960                                    struct diff_filespec *df)
2961 {
2962         struct diff_tempfile *temp = prepare_temp_file(name, df);
2963         argv_array_push(argv, temp->name);
2964         argv_array_push(argv, temp->hex);
2965         argv_array_push(argv, temp->mode);
2966 }
2967
2968 /* An external diff command takes:
2969  *
2970  * diff-cmd name infile1 infile1-sha1 infile1-mode \
2971  *               infile2 infile2-sha1 infile2-mode [ rename-to ]
2972  *
2973  */
2974 static void run_external_diff(const char *pgm,
2975                               const char *name,
2976                               const char *other,
2977                               struct diff_filespec *one,
2978                               struct diff_filespec *two,
2979                               const char *xfrm_msg,
2980                               int complete_rewrite,
2981                               struct diff_options *o)
2982 {
2983         struct argv_array argv = ARGV_ARRAY_INIT;
2984         struct argv_array env = ARGV_ARRAY_INIT;
2985         struct diff_queue_struct *q = &diff_queued_diff;
2986
2987         argv_array_push(&argv, pgm);
2988         argv_array_push(&argv, name);
2989
2990         if (one && two) {
2991                 add_external_diff_name(&argv, name, one);
2992                 if (!other)
2993                         add_external_diff_name(&argv, name, two);
2994                 else {
2995                         add_external_diff_name(&argv, other, two);
2996                         argv_array_push(&argv, other);
2997                         argv_array_push(&argv, xfrm_msg);
2998                 }
2999         }
3000
3001         argv_array_pushf(&env, "GIT_DIFF_PATH_COUNTER=%d", ++o->diff_path_counter);
3002         argv_array_pushf(&env, "GIT_DIFF_PATH_TOTAL=%d", q->nr);
3003
3004         if (run_command_v_opt_cd_env(argv.argv, RUN_USING_SHELL, NULL, env.argv))
3005                 die(_("external diff died, stopping at %s"), name);
3006
3007         remove_tempfile();
3008         argv_array_clear(&argv);
3009         argv_array_clear(&env);
3010 }
3011
3012 static int similarity_index(struct diff_filepair *p)
3013 {
3014         return p->score * 100 / MAX_SCORE;
3015 }
3016
3017 static void fill_metainfo(struct strbuf *msg,
3018                           const char *name,
3019                           const char *other,
3020                           struct diff_filespec *one,
3021                           struct diff_filespec *two,
3022                           struct diff_options *o,
3023                           struct diff_filepair *p,
3024                           int *must_show_header,
3025                           int use_color)
3026 {
3027         const char *set = diff_get_color(use_color, DIFF_METAINFO);
3028         const char *reset = diff_get_color(use_color, DIFF_RESET);
3029         const char *line_prefix = diff_line_prefix(o);
3030
3031         *must_show_header = 1;
3032         strbuf_init(msg, PATH_MAX * 2 + 300);
3033         switch (p->status) {
3034         case DIFF_STATUS_COPIED:
3035                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
3036                             line_prefix, set, similarity_index(p));
3037                 strbuf_addf(msg, "%s\n%s%scopy from ",
3038                             reset,  line_prefix, set);
3039                 quote_c_style(name, msg, NULL, 0);
3040                 strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
3041                 quote_c_style(other, msg, NULL, 0);
3042                 strbuf_addf(msg, "%s\n", reset);
3043                 break;
3044         case DIFF_STATUS_RENAMED:
3045                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
3046                             line_prefix, set, similarity_index(p));
3047                 strbuf_addf(msg, "%s\n%s%srename from ",
3048                             reset, line_prefix, set);
3049                 quote_c_style(name, msg, NULL, 0);
3050                 strbuf_addf(msg, "%s\n%s%srename to ",
3051                             reset, line_prefix, set);
3052                 quote_c_style(other, msg, NULL, 0);
3053                 strbuf_addf(msg, "%s\n", reset);
3054                 break;
3055         case DIFF_STATUS_MODIFIED:
3056                 if (p->score) {
3057                         strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
3058                                     line_prefix,
3059                                     set, similarity_index(p), reset);
3060                         break;
3061                 }
3062                 /* fallthru */
3063         default:
3064                 *must_show_header = 0;
3065         }
3066         if (one && two && hashcmp(one->sha1, two->sha1)) {
3067                 int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
3068
3069                 if (DIFF_OPT_TST(o, BINARY)) {
3070                         mmfile_t mf;
3071                         if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
3072                             (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
3073                                 abbrev = 40;
3074                 }
3075                 strbuf_addf(msg, "%s%sindex %s..", line_prefix, set,
3076                             find_unique_abbrev(one->sha1, abbrev));
3077                 strbuf_addstr(msg, find_unique_abbrev(two->sha1, abbrev));
3078                 if (one->mode == two->mode)
3079                         strbuf_addf(msg, " %06o", one->mode);
3080                 strbuf_addf(msg, "%s\n", reset);
3081         }
3082 }
3083
3084 static void run_diff_cmd(const char *pgm,
3085                          const char *name,
3086                          const char *other,
3087                          const char *attr_path,
3088                          struct diff_filespec *one,
3089                          struct diff_filespec *two,
3090                          struct strbuf *msg,
3091                          struct diff_options *o,
3092                          struct diff_filepair *p)
3093 {
3094         const char *xfrm_msg = NULL;
3095         int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
3096         int must_show_header = 0;
3097
3098
3099         if (DIFF_OPT_TST(o, ALLOW_EXTERNAL)) {
3100                 struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
3101                 if (drv && drv->external)
3102                         pgm = drv->external;
3103         }
3104
3105         if (msg) {
3106                 /*
3107                  * don't use colors when the header is intended for an
3108                  * external diff driver
3109                  */
3110                 fill_metainfo(msg, name, other, one, two, o, p,
3111                               &must_show_header,
3112                               want_color(o->use_color) && !pgm);
3113                 xfrm_msg = msg->len ? msg->buf : NULL;
3114         }
3115
3116         if (pgm) {
3117                 run_external_diff(pgm, name, other, one, two, xfrm_msg,
3118                                   complete_rewrite, o);
3119                 return;
3120         }
3121         if (one && two)
3122                 builtin_diff(name, other ? other : name,
3123                              one, two, xfrm_msg, must_show_header,
3124                              o, complete_rewrite);
3125         else
3126                 fprintf(o->file, "* Unmerged path %s\n", name);
3127 }
3128
3129 static void diff_fill_sha1_info(struct diff_filespec *one)
3130 {
3131         if (DIFF_FILE_VALID(one)) {
3132                 if (!one->sha1_valid) {
3133                         struct stat st;
3134                         if (one->is_stdin) {
3135                                 hashcpy(one->sha1, null_sha1);
3136                                 return;
3137                         }
3138                         if (lstat(one->path, &st) < 0)
3139                                 die_errno("stat '%s'", one->path);
3140                         if (index_path(one->sha1, one->path, &st, 0))
3141                                 die("cannot hash %s", one->path);
3142                 }
3143         }
3144         else
3145                 hashclr(one->sha1);
3146 }
3147
3148 static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
3149 {
3150         /* Strip the prefix but do not molest /dev/null and absolute paths */
3151         if (*namep && **namep != '/') {
3152                 *namep += prefix_length;
3153                 if (**namep == '/')
3154                         ++*namep;
3155         }
3156         if (*otherp && **otherp != '/') {
3157                 *otherp += prefix_length;
3158                 if (**otherp == '/')
3159                         ++*otherp;
3160         }
3161 }
3162
3163 static void run_diff(struct diff_filepair *p, struct diff_options *o)
3164 {
3165         const char *pgm = external_diff();
3166         struct strbuf msg;
3167         struct diff_filespec *one = p->one;
3168         struct diff_filespec *two = p->two;
3169         const char *name;
3170         const char *other;
3171         const char *attr_path;
3172
3173         name  = p->one->path;
3174         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3175         attr_path = name;
3176         if (o->prefix_length)
3177                 strip_prefix(o->prefix_length, &name, &other);
3178
3179         if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
3180                 pgm = NULL;
3181
3182         if (DIFF_PAIR_UNMERGED(p)) {
3183                 run_diff_cmd(pgm, name, NULL, attr_path,
3184                              NULL, NULL, NULL, o, p);
3185                 return;
3186         }
3187
3188         diff_fill_sha1_info(one);
3189         diff_fill_sha1_info(two);
3190
3191         if (!pgm &&
3192             DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
3193             (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
3194                 /*
3195                  * a filepair that changes between file and symlink
3196                  * needs to be split into deletion and creation.
3197                  */
3198                 struct diff_filespec *null = alloc_filespec(two->path);
3199                 run_diff_cmd(NULL, name, other, attr_path,
3200                              one, null, &msg, o, p);
3201                 free(null);
3202                 strbuf_release(&msg);
3203
3204                 null = alloc_filespec(one->path);
3205                 run_diff_cmd(NULL, name, other, attr_path,
3206                              null, two, &msg, o, p);
3207                 free(null);
3208         }
3209         else
3210                 run_diff_cmd(pgm, name, other, attr_path,
3211                              one, two, &msg, o, p);
3212
3213         strbuf_release(&msg);
3214 }
3215
3216 static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
3217                          struct diffstat_t *diffstat)
3218 {
3219         const char *name;
3220         const char *other;
3221
3222         if (DIFF_PAIR_UNMERGED(p)) {
3223                 /* unmerged */
3224                 builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, p);
3225                 return;
3226         }
3227
3228         name = p->one->path;
3229         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3230
3231         if (o->prefix_length)
3232                 strip_prefix(o->prefix_length, &name, &other);
3233
3234         diff_fill_sha1_info(p->one);
3235         diff_fill_sha1_info(p->two);
3236
3237         builtin_diffstat(name, other, p->one, p->two, diffstat, o, p);
3238 }
3239
3240 static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
3241 {
3242         const char *name;
3243         const char *other;
3244         const char *attr_path;
3245
3246         if (DIFF_PAIR_UNMERGED(p)) {
3247                 /* unmerged */
3248                 return;
3249         }
3250
3251         name = p->one->path;
3252         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3253         attr_path = other ? other : name;
3254
3255         if (o->prefix_length)
3256                 strip_prefix(o->prefix_length, &name, &other);
3257
3258         diff_fill_sha1_info(p->one);
3259         diff_fill_sha1_info(p->two);
3260
3261         builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
3262 }
3263
3264 void diff_setup(struct diff_options *options)
3265 {
3266         memcpy(options, &default_diff_options, sizeof(*options));
3267
3268         options->file = stdout;
3269
3270         options->line_termination = '\n';
3271         options->break_opt = -1;
3272         options->rename_limit = -1;
3273         options->dirstat_permille = diff_dirstat_permille_default;
3274         options->context = diff_context_default;
3275         options->ws_error_highlight = WSEH_NEW;
3276         DIFF_OPT_SET(options, RENAME_EMPTY);
3277
3278         /* pathchange left =NULL by default */
3279         options->change = diff_change;
3280         options->add_remove = diff_addremove;
3281         options->use_color = diff_use_color_default;
3282         options->detect_rename = diff_detect_rename_default;
3283         options->xdl_opts |= diff_algorithm;
3284
3285         options->orderfile = diff_order_file_cfg;
3286
3287         if (diff_no_prefix) {
3288                 options->a_prefix = options->b_prefix = "";
3289         } else if (!diff_mnemonic_prefix) {
3290                 options->a_prefix = "a/";
3291                 options->b_prefix = "b/";
3292         }
3293 }
3294
3295 void diff_setup_done(struct diff_options *options)
3296 {
3297         int count = 0;
3298
3299         if (options->set_default)
3300                 options->set_default(options);
3301
3302         if (options->output_format & DIFF_FORMAT_NAME)
3303                 count++;
3304         if (options->output_format & DIFF_FORMAT_NAME_STATUS)
3305                 count++;
3306         if (options->output_format & DIFF_FORMAT_CHECKDIFF)
3307                 count++;
3308         if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
3309                 count++;
3310         if (count > 1)
3311                 die("--name-only, --name-status, --check and -s are mutually exclusive");
3312
3313         /*
3314          * Most of the time we can say "there are changes"
3315          * only by checking if there are changed paths, but
3316          * --ignore-whitespace* options force us to look
3317          * inside contents.
3318          */
3319
3320         if (DIFF_XDL_TST(options, IGNORE_WHITESPACE) ||
3321             DIFF_XDL_TST(options, IGNORE_WHITESPACE_CHANGE) ||
3322             DIFF_XDL_TST(options, IGNORE_WHITESPACE_AT_EOL))
3323                 DIFF_OPT_SET(options, DIFF_FROM_CONTENTS);
3324         else
3325                 DIFF_OPT_CLR(options, DIFF_FROM_CONTENTS);
3326
3327         if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
3328                 options->detect_rename = DIFF_DETECT_COPY;
3329
3330         if (!DIFF_OPT_TST(options, RELATIVE_NAME))
3331                 options->prefix = NULL;
3332         if (options->prefix)
3333                 options->prefix_length = strlen(options->prefix);
3334         else
3335                 options->prefix_length = 0;
3336
3337         if (options->output_format & (DIFF_FORMAT_NAME |
3338                                       DIFF_FORMAT_NAME_STATUS |
3339                                       DIFF_FORMAT_CHECKDIFF |
3340                                       DIFF_FORMAT_NO_OUTPUT))
3341                 options->output_format &= ~(DIFF_FORMAT_RAW |
3342                                             DIFF_FORMAT_NUMSTAT |
3343                                             DIFF_FORMAT_DIFFSTAT |
3344                                             DIFF_FORMAT_SHORTSTAT |
3345                                             DIFF_FORMAT_DIRSTAT |
3346                                             DIFF_FORMAT_SUMMARY |
3347                                             DIFF_FORMAT_PATCH);
3348
3349         /*
3350          * These cases always need recursive; we do not drop caller-supplied
3351          * recursive bits for other formats here.
3352          */
3353         if (options->output_format & (DIFF_FORMAT_PATCH |
3354                                       DIFF_FORMAT_NUMSTAT |
3355                                       DIFF_FORMAT_DIFFSTAT |
3356                                       DIFF_FORMAT_SHORTSTAT |
3357                                       DIFF_FORMAT_DIRSTAT |
3358                                       DIFF_FORMAT_SUMMARY |
3359                                       DIFF_FORMAT_CHECKDIFF))
3360                 DIFF_OPT_SET(options, RECURSIVE);
3361         /*
3362          * Also pickaxe would not work very well if you do not say recursive
3363          */
3364         if (options->pickaxe)
3365                 DIFF_OPT_SET(options, RECURSIVE);
3366         /*
3367          * When patches are generated, submodules diffed against the work tree
3368          * must be checked for dirtiness too so it can be shown in the output
3369          */
3370         if (options->output_format & DIFF_FORMAT_PATCH)
3371                 DIFF_OPT_SET(options, DIRTY_SUBMODULES);
3372
3373         if (options->detect_rename && options->rename_limit < 0)
3374                 options->rename_limit = diff_rename_limit_default;
3375         if (options->setup & DIFF_SETUP_USE_CACHE) {
3376                 if (!active_cache)
3377                         /* read-cache does not die even when it fails
3378                          * so it is safe for us to do this here.  Also
3379                          * it does not smudge active_cache or active_nr
3380                          * when it fails, so we do not have to worry about
3381                          * cleaning it up ourselves either.
3382                          */
3383                         read_cache();
3384         }
3385         if (options->abbrev <= 0 || 40 < options->abbrev)
3386                 options->abbrev = 40; /* full */
3387
3388         /*
3389          * It does not make sense to show the first hit we happened
3390          * to have found.  It does not make sense not to return with
3391          * exit code in such a case either.
3392          */
3393         if (DIFF_OPT_TST(options, QUICK)) {
3394                 options->output_format = DIFF_FORMAT_NO_OUTPUT;
3395                 DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3396         }
3397
3398         options->diff_path_counter = 0;
3399
3400         if (DIFF_OPT_TST(options, FOLLOW_RENAMES) && options->pathspec.nr != 1)
3401                 die(_("--follow requires exactly one pathspec"));
3402 }
3403
3404 static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
3405 {
3406         char c, *eq;
3407         int len;
3408
3409         if (*arg != '-')
3410                 return 0;
3411         c = *++arg;
3412         if (!c)
3413                 return 0;
3414         if (c == arg_short) {
3415                 c = *++arg;
3416                 if (!c)
3417                         return 1;
3418                 if (val && isdigit(c)) {
3419                         char *end;
3420                         int n = strtoul(arg, &end, 10);
3421                         if (*end)
3422                                 return 0;
3423                         *val = n;
3424                         return 1;
3425                 }
3426                 return 0;
3427         }
3428         if (c != '-')
3429                 return 0;
3430         arg++;
3431         eq = strchrnul(arg, '=');
3432         len = eq - arg;
3433         if (!len || strncmp(arg, arg_long, len))
3434                 return 0;
3435         if (*eq) {
3436                 int n;
3437                 char *end;
3438                 if (!isdigit(*++eq))
3439                         return 0;
3440                 n = strtoul(eq, &end, 10);
3441                 if (*end)
3442                         return 0;
3443                 *val = n;
3444         }
3445         return 1;
3446 }
3447
3448 static int diff_scoreopt_parse(const char *opt);
3449
3450 static inline int short_opt(char opt, const char **argv,
3451                             const char **optarg)
3452 {
3453         const char *arg = argv[0];
3454         if (arg[0] != '-' || arg[1] != opt)
3455                 return 0;
3456         if (arg[2] != '\0') {
3457                 *optarg = arg + 2;
3458                 return 1;
3459         }
3460         if (!argv[1])
3461                 die("Option '%c' requires a value", opt);
3462         *optarg = argv[1];
3463         return 2;
3464 }
3465
3466 int parse_long_opt(const char *opt, const char **argv,
3467                    const char **optarg)
3468 {
3469         const char *arg = argv[0];
3470         if (!skip_prefix(arg, "--", &arg))
3471                 return 0;
3472         if (!skip_prefix(arg, opt, &arg))
3473                 return 0;
3474         if (*arg == '=') { /* stuck form: --option=value */
3475                 *optarg = arg + 1;
3476                 return 1;
3477         }
3478         if (*arg != '\0')
3479                 return 0;
3480         /* separate form: --option value */
3481         if (!argv[1])
3482                 die("Option '--%s' requires a value", opt);
3483         *optarg = argv[1];
3484         return 2;
3485 }
3486
3487 static int stat_opt(struct diff_options *options, const char **av)
3488 {
3489         const char *arg = av[0];
3490         char *end;
3491         int width = options->stat_width;
3492         int name_width = options->stat_name_width;
3493         int graph_width = options->stat_graph_width;
3494         int count = options->stat_count;
3495         int argcount = 1;
3496
3497         if (!skip_prefix(arg, "--stat", &arg))
3498                 die("BUG: stat option does not begin with --stat: %s", arg);
3499         end = (char *)arg;
3500
3501         switch (*arg) {
3502         case '-':
3503                 if (skip_prefix(arg, "-width", &arg)) {
3504                         if (*arg == '=')
3505                                 width = strtoul(arg + 1, &end, 10);
3506                         else if (!*arg && !av[1])
3507                                 die("Option '--stat-width' requires a value");
3508                         else if (!*arg) {
3509                                 width = strtoul(av[1], &end, 10);
3510                                 argcount = 2;
3511                         }
3512                 } else if (skip_prefix(arg, "-name-width", &arg)) {
3513                         if (*arg == '=')
3514                                 name_width = strtoul(arg + 1, &end, 10);
3515                         else if (!*arg && !av[1])
3516                                 die("Option '--stat-name-width' requires a value");
3517                         else if (!*arg) {
3518                                 name_width = strtoul(av[1], &end, 10);
3519                                 argcount = 2;
3520                         }
3521                 } else if (skip_prefix(arg, "-graph-width", &arg)) {
3522                         if (*arg == '=')
3523                                 graph_width = strtoul(arg + 1, &end, 10);
3524                         else if (!*arg && !av[1])
3525                                 die("Option '--stat-graph-width' requires a value");
3526                         else if (!*arg) {
3527                                 graph_width = strtoul(av[1], &end, 10);
3528                                 argcount = 2;
3529                         }
3530                 } else if (skip_prefix(arg, "-count", &arg)) {
3531                         if (*arg == '=')
3532                                 count = strtoul(arg + 1, &end, 10);
3533                         else if (!*arg && !av[1])
3534                                 die("Option '--stat-count' requires a value");
3535                         else if (!*arg) {
3536                                 count = strtoul(av[1], &end, 10);
3537                                 argcount = 2;
3538                         }
3539                 }
3540                 break;
3541         case '=':
3542                 width = strtoul(arg+1, &end, 10);
3543                 if (*end == ',')
3544                         name_width = strtoul(end+1, &end, 10);
3545                 if (*end == ',')
3546                         count = strtoul(end+1, &end, 10);
3547         }
3548
3549         /* Important! This checks all the error cases! */
3550         if (*end)
3551                 return 0;
3552         options->output_format |= DIFF_FORMAT_DIFFSTAT;
3553         options->stat_name_width = name_width;
3554         options->stat_graph_width = graph_width;
3555         options->stat_width = width;
3556         options->stat_count = count;
3557         return argcount;
3558 }
3559
3560 static int parse_dirstat_opt(struct diff_options *options, const char *params)
3561 {
3562         struct strbuf errmsg = STRBUF_INIT;
3563         if (parse_dirstat_params(options, params, &errmsg))
3564                 die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
3565                     errmsg.buf);
3566         strbuf_release(&errmsg);
3567         /*
3568          * The caller knows a dirstat-related option is given from the command
3569          * line; allow it to say "return this_function();"
3570          */
3571         options->output_format |= DIFF_FORMAT_DIRSTAT;
3572         return 1;
3573 }
3574
3575 static int parse_submodule_opt(struct diff_options *options, const char *value)
3576 {
3577         if (parse_submodule_params(options, value))
3578                 die(_("Failed to parse --submodule option parameter: '%s'"),
3579                         value);
3580         return 1;
3581 }
3582
3583 static const char diff_status_letters[] = {
3584         DIFF_STATUS_ADDED,
3585         DIFF_STATUS_COPIED,
3586         DIFF_STATUS_DELETED,
3587         DIFF_STATUS_MODIFIED,
3588         DIFF_STATUS_RENAMED,
3589         DIFF_STATUS_TYPE_CHANGED,
3590         DIFF_STATUS_UNKNOWN,
3591         DIFF_STATUS_UNMERGED,
3592         DIFF_STATUS_FILTER_AON,
3593         DIFF_STATUS_FILTER_BROKEN,
3594         '\0',
3595 };
3596
3597 static unsigned int filter_bit['Z' + 1];
3598
3599 static void prepare_filter_bits(void)
3600 {
3601         int i;
3602
3603         if (!filter_bit[DIFF_STATUS_ADDED]) {
3604                 for (i = 0; diff_status_letters[i]; i++)
3605                         filter_bit[(int) diff_status_letters[i]] = (1 << i);
3606         }
3607 }
3608
3609 static unsigned filter_bit_tst(char status, const struct diff_options *opt)
3610 {
3611         return opt->filter & filter_bit[(int) status];
3612 }
3613
3614 static int parse_diff_filter_opt(const char *optarg, struct diff_options *opt)
3615 {
3616         int i, optch;
3617
3618         prepare_filter_bits();
3619
3620         /*
3621          * If there is a negation e.g. 'd' in the input, and we haven't
3622          * initialized the filter field with another --diff-filter, start
3623          * from full set of bits, except for AON.
3624          */
3625         if (!opt->filter) {
3626                 for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3627                         if (optch < 'a' || 'z' < optch)
3628                                 continue;
3629                         opt->filter = (1 << (ARRAY_SIZE(diff_status_letters) - 1)) - 1;
3630                         opt->filter &= ~filter_bit[DIFF_STATUS_FILTER_AON];
3631                         break;
3632                 }
3633         }
3634
3635         for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3636                 unsigned int bit;
3637                 int negate;
3638
3639                 if ('a' <= optch && optch <= 'z') {
3640                         negate = 1;
3641                         optch = toupper(optch);
3642                 } else {
3643                         negate = 0;
3644                 }
3645
3646                 bit = (0 <= optch && optch <= 'Z') ? filter_bit[optch] : 0;
3647                 if (!bit)
3648                         return optarg[i];
3649                 if (negate)
3650                         opt->filter &= ~bit;
3651                 else
3652                         opt->filter |= bit;
3653         }
3654         return 0;
3655 }
3656
3657 static void enable_patch_output(int *fmt) {
3658         *fmt &= ~DIFF_FORMAT_NO_OUTPUT;
3659         *fmt |= DIFF_FORMAT_PATCH;
3660 }
3661
3662 static int parse_one_token(const char **arg, const char *token)
3663 {
3664         const char *rest;
3665         if (skip_prefix(*arg, token, &rest) && (!*rest || *rest == ',')) {
3666                 *arg = rest;
3667                 return 1;
3668         }
3669         return 0;
3670 }
3671
3672 static int parse_ws_error_highlight(struct diff_options *opt, const char *arg)
3673 {
3674         const char *orig_arg = arg;
3675         unsigned val = 0;
3676         while (*arg) {
3677                 if (parse_one_token(&arg, "none"))
3678                         val = 0;
3679                 else if (parse_one_token(&arg, "default"))
3680                         val = WSEH_NEW;
3681                 else if (parse_one_token(&arg, "all"))
3682                         val = WSEH_NEW | WSEH_OLD | WSEH_CONTEXT;
3683                 else if (parse_one_token(&arg, "new"))
3684                         val |= WSEH_NEW;
3685                 else if (parse_one_token(&arg, "old"))
3686                         val |= WSEH_OLD;
3687                 else if (parse_one_token(&arg, "context"))
3688                         val |= WSEH_CONTEXT;
3689                 else {
3690                         error("unknown value after ws-error-highlight=%.*s",
3691                               (int)(arg - orig_arg), orig_arg);
3692                         return 0;
3693                 }
3694                 if (*arg)
3695                         arg++;
3696         }
3697         opt->ws_error_highlight = val;
3698         return 1;
3699 }
3700
3701 int diff_opt_parse(struct diff_options *options,
3702                    const char **av, int ac, const char *prefix)
3703 {
3704         const char *arg = av[0];
3705         const char *optarg;
3706         int argcount;
3707
3708         if (!prefix)
3709                 prefix = "";
3710
3711         /* Output format options */
3712         if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch")
3713             || opt_arg(arg, 'U', "unified", &options->context))
3714                 enable_patch_output(&options->output_format);
3715         else if (!strcmp(arg, "--raw"))
3716                 options->output_format |= DIFF_FORMAT_RAW;
3717         else if (!strcmp(arg, "--patch-with-raw")) {
3718                 enable_patch_output(&options->output_format);
3719                 options->output_format |= DIFF_FORMAT_RAW;
3720         } else if (!strcmp(arg, "--numstat"))
3721                 options->output_format |= DIFF_FORMAT_NUMSTAT;
3722         else if (!strcmp(arg, "--shortstat"))
3723                 options->output_format |= DIFF_FORMAT_SHORTSTAT;
3724         else if (!strcmp(arg, "-X") || !strcmp(arg, "--dirstat"))
3725                 return parse_dirstat_opt(options, "");
3726         else if (skip_prefix(arg, "-X", &arg))
3727                 return parse_dirstat_opt(options, arg);
3728         else if (skip_prefix(arg, "--dirstat=", &arg))
3729                 return parse_dirstat_opt(options, arg);
3730         else if (!strcmp(arg, "--cumulative"))
3731                 return parse_dirstat_opt(options, "cumulative");
3732         else if (!strcmp(arg, "--dirstat-by-file"))
3733                 return parse_dirstat_opt(options, "files");
3734         else if (skip_prefix(arg, "--dirstat-by-file=", &arg)) {
3735                 parse_dirstat_opt(options, "files");
3736                 return parse_dirstat_opt(options, arg);
3737         }
3738         else if (!strcmp(arg, "--check"))
3739                 options->output_format |= DIFF_FORMAT_CHECKDIFF;
3740         else if (!strcmp(arg, "--summary"))
3741                 options->output_format |= DIFF_FORMAT_SUMMARY;
3742         else if (!strcmp(arg, "--patch-with-stat")) {
3743                 enable_patch_output(&options->output_format);
3744                 options->output_format |= DIFF_FORMAT_DIFFSTAT;
3745         } else if (!strcmp(arg, "--name-only"))
3746                 options->output_format |= DIFF_FORMAT_NAME;
3747         else if (!strcmp(arg, "--name-status"))
3748                 options->output_format |= DIFF_FORMAT_NAME_STATUS;
3749         else if (!strcmp(arg, "-s") || !strcmp(arg, "--no-patch"))
3750                 options->output_format |= DIFF_FORMAT_NO_OUTPUT;
3751         else if (starts_with(arg, "--stat"))
3752                 /* --stat, --stat-width, --stat-name-width, or --stat-count */
3753                 return stat_opt(options, av);
3754
3755         /* renames options */
3756         else if (starts_with(arg, "-B") || starts_with(arg, "--break-rewrites=") ||
3757                  !strcmp(arg, "--break-rewrites")) {
3758                 if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
3759                         return error("invalid argument to -B: %s", arg+2);
3760         }
3761         else if (starts_with(arg, "-M") || starts_with(arg, "--find-renames=") ||
3762                  !strcmp(arg, "--find-renames")) {
3763                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3764                         return error("invalid argument to -M: %s", arg+2);
3765                 options->detect_rename = DIFF_DETECT_RENAME;
3766         }
3767         else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
3768                 options->irreversible_delete = 1;
3769         }
3770         else if (starts_with(arg, "-C") || starts_with(arg, "--find-copies=") ||
3771                  !strcmp(arg, "--find-copies")) {
3772                 if (options->detect_rename == DIFF_DETECT_COPY)
3773                         DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3774                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3775                         return error("invalid argument to -C: %s", arg+2);
3776                 options->detect_rename = DIFF_DETECT_COPY;
3777         }
3778         else if (!strcmp(arg, "--no-renames"))
3779                 options->detect_rename = 0;
3780         else if (!strcmp(arg, "--rename-empty"))
3781                 DIFF_OPT_SET(options, RENAME_EMPTY);
3782         else if (!strcmp(arg, "--no-rename-empty"))
3783                 DIFF_OPT_CLR(options, RENAME_EMPTY);
3784         else if (!strcmp(arg, "--relative"))
3785                 DIFF_OPT_SET(options, RELATIVE_NAME);
3786         else if (skip_prefix(arg, "--relative=", &arg)) {
3787                 DIFF_OPT_SET(options, RELATIVE_NAME);
3788                 options->prefix = arg;
3789         }
3790
3791         /* xdiff options */
3792         else if (!strcmp(arg, "--minimal"))
3793                 DIFF_XDL_SET(options, NEED_MINIMAL);
3794         else if (!strcmp(arg, "--no-minimal"))
3795                 DIFF_XDL_CLR(options, NEED_MINIMAL);
3796         else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
3797                 DIFF_XDL_SET(options, IGNORE_WHITESPACE);
3798         else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
3799                 DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
3800         else if (!strcmp(arg, "--ignore-space-at-eol"))
3801                 DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
3802         else if (!strcmp(arg, "--ignore-blank-lines"))
3803                 DIFF_XDL_SET(options, IGNORE_BLANK_LINES);
3804         else if (!strcmp(arg, "--patience"))
3805                 options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
3806         else if (!strcmp(arg, "--histogram"))
3807                 options->xdl_opts = DIFF_WITH_ALG(options, HISTOGRAM_DIFF);
3808         else if ((argcount = parse_long_opt("diff-algorithm", av, &optarg))) {
3809                 long value = parse_algorithm_value(optarg);
3810                 if (value < 0)
3811                         return error("option diff-algorithm accepts \"myers\", "
3812                                      "\"minimal\", \"patience\" and \"histogram\"");
3813                 /* clear out previous settings */
3814                 DIFF_XDL_CLR(options, NEED_MINIMAL);
3815                 options->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
3816                 options->xdl_opts |= value;
3817                 return argcount;
3818         }
3819
3820         /* flags options */
3821         else if (!strcmp(arg, "--binary")) {
3822                 enable_patch_output(&options->output_format);
3823                 DIFF_OPT_SET(options, BINARY);
3824         }
3825         else if (!strcmp(arg, "--full-index"))
3826                 DIFF_OPT_SET(options, FULL_INDEX);
3827         else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
3828                 DIFF_OPT_SET(options, TEXT);
3829         else if (!strcmp(arg, "-R"))
3830                 DIFF_OPT_SET(options, REVERSE_DIFF);
3831         else if (!strcmp(arg, "--find-copies-harder"))
3832                 DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3833         else if (!strcmp(arg, "--follow"))
3834                 DIFF_OPT_SET(options, FOLLOW_RENAMES);
3835         else if (!strcmp(arg, "--no-follow")) {
3836                 DIFF_OPT_CLR(options, FOLLOW_RENAMES);
3837                 DIFF_OPT_CLR(options, DEFAULT_FOLLOW_RENAMES);
3838         } else if (!strcmp(arg, "--color"))
3839                 options->use_color = 1;
3840         else if (skip_prefix(arg, "--color=", &arg)) {
3841                 int value = git_config_colorbool(NULL, arg);
3842                 if (value < 0)
3843                         return error("option `color' expects \"always\", \"auto\", or \"never\"");
3844                 options->use_color = value;
3845         }
3846         else if (!strcmp(arg, "--no-color"))
3847                 options->use_color = 0;
3848         else if (!strcmp(arg, "--color-words")) {
3849                 options->use_color = 1;
3850                 options->word_diff = DIFF_WORDS_COLOR;
3851         }
3852         else if (skip_prefix(arg, "--color-words=", &arg)) {
3853                 options->use_color = 1;
3854                 options->word_diff = DIFF_WORDS_COLOR;
3855                 options->word_regex = arg;
3856         }
3857         else if (!strcmp(arg, "--word-diff")) {
3858                 if (options->word_diff == DIFF_WORDS_NONE)
3859                         options->word_diff = DIFF_WORDS_PLAIN;
3860         }
3861         else if (skip_prefix(arg, "--word-diff=", &arg)) {
3862                 if (!strcmp(arg, "plain"))
3863                         options->word_diff = DIFF_WORDS_PLAIN;
3864                 else if (!strcmp(arg, "color")) {
3865                         options->use_color = 1;
3866                         options->word_diff = DIFF_WORDS_COLOR;
3867                 }
3868                 else if (!strcmp(arg, "porcelain"))
3869                         options->word_diff = DIFF_WORDS_PORCELAIN;
3870                 else if (!strcmp(arg, "none"))
3871                         options->word_diff = DIFF_WORDS_NONE;
3872                 else
3873                         die("bad --word-diff argument: %s", arg);
3874         }
3875         else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
3876                 if (options->word_diff == DIFF_WORDS_NONE)
3877                         options->word_diff = DIFF_WORDS_PLAIN;
3878                 options->word_regex = optarg;
3879                 return argcount;
3880         }
3881         else if (!strcmp(arg, "--exit-code"))
3882                 DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3883         else if (!strcmp(arg, "--quiet"))
3884                 DIFF_OPT_SET(options, QUICK);
3885         else if (!strcmp(arg, "--ext-diff"))
3886                 DIFF_OPT_SET(options, ALLOW_EXTERNAL);
3887         else if (!strcmp(arg, "--no-ext-diff"))
3888                 DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
3889         else if (!strcmp(arg, "--textconv"))
3890                 DIFF_OPT_SET(options, ALLOW_TEXTCONV);
3891         else if (!strcmp(arg, "--no-textconv"))
3892                 DIFF_OPT_CLR(options, ALLOW_TEXTCONV);
3893         else if (!strcmp(arg, "--ignore-submodules")) {
3894                 DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3895                 handle_ignore_submodules_arg(options, "all");
3896         } else if (skip_prefix(arg, "--ignore-submodules=", &arg)) {
3897                 DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
3898                 handle_ignore_submodules_arg(options, arg);
3899         } else if (!strcmp(arg, "--submodule"))
3900                 DIFF_OPT_SET(options, SUBMODULE_LOG);
3901         else if (skip_prefix(arg, "--submodule=", &arg))
3902                 return parse_submodule_opt(options, arg);
3903         else if (skip_prefix(arg, "--ws-error-highlight=", &arg))
3904                 return parse_ws_error_highlight(options, arg);
3905
3906         /* misc options */
3907         else if (!strcmp(arg, "-z"))
3908                 options->line_termination = 0;
3909         else if ((argcount = short_opt('l', av, &optarg))) {
3910                 options->rename_limit = strtoul(optarg, NULL, 10);
3911                 return argcount;
3912         }
3913         else if ((argcount = short_opt('S', av, &optarg))) {
3914                 options->pickaxe = optarg;
3915                 options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
3916                 return argcount;
3917         } else if ((argcount = short_opt('G', av, &optarg))) {
3918                 options->pickaxe = optarg;
3919                 options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
3920                 return argcount;
3921         }
3922         else if (!strcmp(arg, "--pickaxe-all"))
3923                 options->pickaxe_opts |= DIFF_PICKAXE_ALL;
3924         else if (!strcmp(arg, "--pickaxe-regex"))
3925                 options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
3926         else if ((argcount = short_opt('O', av, &optarg))) {
3927                 const char *path = prefix_filename(prefix, strlen(prefix), optarg);
3928                 options->orderfile = xstrdup(path);
3929                 return argcount;
3930         }
3931         else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
3932                 int offending = parse_diff_filter_opt(optarg, options);
3933                 if (offending)
3934                         die("unknown change class '%c' in --diff-filter=%s",
3935                             offending, optarg);
3936                 return argcount;
3937         }
3938         else if (!strcmp(arg, "--abbrev"))
3939                 options->abbrev = DEFAULT_ABBREV;
3940         else if (skip_prefix(arg, "--abbrev=", &arg)) {
3941                 options->abbrev = strtoul(arg, NULL, 10);
3942                 if (options->abbrev < MINIMUM_ABBREV)
3943                         options->abbrev = MINIMUM_ABBREV;
3944                 else if (40 < options->abbrev)
3945                         options->abbrev = 40;
3946         }
3947         else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
3948                 options->a_prefix = optarg;
3949                 return argcount;
3950         }
3951         else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
3952                 options->b_prefix = optarg;
3953                 return argcount;
3954         }
3955         else if (!strcmp(arg, "--no-prefix"))
3956                 options->a_prefix = options->b_prefix = "";
3957         else if (opt_arg(arg, '\0', "inter-hunk-context",
3958                          &options->interhunkcontext))
3959                 ;
3960         else if (!strcmp(arg, "-W"))
3961                 DIFF_OPT_SET(options, FUNCCONTEXT);
3962         else if (!strcmp(arg, "--function-context"))
3963                 DIFF_OPT_SET(options, FUNCCONTEXT);
3964         else if (!strcmp(arg, "--no-function-context"))
3965                 DIFF_OPT_CLR(options, FUNCCONTEXT);
3966         else if ((argcount = parse_long_opt("output", av, &optarg))) {
3967                 const char *path = prefix_filename(prefix, strlen(prefix), optarg);
3968                 options->file = fopen(path, "w");
3969                 if (!options->file)
3970                         die_errno("Could not open '%s'", path);
3971                 options->close_file = 1;
3972                 return argcount;
3973         } else
3974                 return 0;
3975         return 1;
3976 }
3977
3978 int parse_rename_score(const char **cp_p)
3979 {
3980         unsigned long num, scale;
3981         int ch, dot;
3982         const char *cp = *cp_p;
3983
3984         num = 0;
3985         scale = 1;
3986         dot = 0;
3987         for (;;) {
3988                 ch = *cp;
3989                 if ( !dot && ch == '.' ) {
3990                         scale = 1;
3991                         dot = 1;
3992                 } else if ( ch == '%' ) {
3993                         scale = dot ? scale*100 : 100;
3994                         cp++;   /* % is always at the end */
3995                         break;
3996                 } else if ( ch >= '0' && ch <= '9' ) {
3997                         if ( scale < 100000 ) {
3998                                 scale *= 10;
3999                                 num = (num*10) + (ch-'0');
4000                         }
4001                 } else {
4002                         break;
4003                 }
4004                 cp++;
4005         }
4006         *cp_p = cp;
4007
4008         /* user says num divided by scale and we say internally that
4009          * is MAX_SCORE * num / scale.
4010          */
4011         return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
4012 }
4013
4014 static int diff_scoreopt_parse(const char *opt)
4015 {
4016         int opt1, opt2, cmd;
4017
4018         if (*opt++ != '-')
4019                 return -1;
4020         cmd = *opt++;
4021         if (cmd == '-') {
4022                 /* convert the long-form arguments into short-form versions */
4023                 if (skip_prefix(opt, "break-rewrites", &opt)) {
4024                         if (*opt == 0 || *opt++ == '=')
4025                                 cmd = 'B';
4026                 } else if (skip_prefix(opt, "find-copies", &opt)) {
4027                         if (*opt == 0 || *opt++ == '=')
4028                                 cmd = 'C';
4029                 } else if (skip_prefix(opt, "find-renames", &opt)) {
4030                         if (*opt == 0 || *opt++ == '=')
4031                                 cmd = 'M';
4032                 }
4033         }
4034         if (cmd != 'M' && cmd != 'C' && cmd != 'B')
4035                 return -1; /* that is not a -M, -C, or -B option */
4036
4037         opt1 = parse_rename_score(&opt);
4038         if (cmd != 'B')
4039                 opt2 = 0;
4040         else {
4041                 if (*opt == 0)
4042                         opt2 = 0;
4043                 else if (*opt != '/')
4044                         return -1; /* we expect -B80/99 or -B80 */
4045                 else {
4046                         opt++;
4047                         opt2 = parse_rename_score(&opt);
4048                 }
4049         }
4050         if (*opt != 0)
4051                 return -1;
4052         return opt1 | (opt2 << 16);
4053 }
4054
4055 struct diff_queue_struct diff_queued_diff;
4056
4057 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
4058 {
4059         ALLOC_GROW(queue->queue, queue->nr + 1, queue->alloc);
4060         queue->queue[queue->nr++] = dp;
4061 }
4062
4063 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
4064                                  struct diff_filespec *one,
4065                                  struct diff_filespec *two)
4066 {
4067         struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
4068         dp->one = one;
4069         dp->two = two;
4070         if (queue)
4071                 diff_q(queue, dp);
4072         return dp;
4073 }
4074
4075 void diff_free_filepair(struct diff_filepair *p)
4076 {
4077         free_filespec(p->one);
4078         free_filespec(p->two);
4079         free(p);
4080 }
4081
4082 /* This is different from find_unique_abbrev() in that
4083  * it stuffs the result with dots for alignment.
4084  */
4085 const char *diff_unique_abbrev(const unsigned char *sha1, int len)
4086 {
4087         int abblen;
4088         const char *abbrev;
4089         if (len == 40)
4090                 return sha1_to_hex(sha1);
4091
4092         abbrev = find_unique_abbrev(sha1, len);
4093         abblen = strlen(abbrev);
4094         if (abblen < 37) {
4095                 static char hex[41];
4096                 if (len < abblen && abblen <= len + 2)
4097                         xsnprintf(hex, sizeof(hex), "%s%.*s", abbrev, len+3-abblen, "..");
4098                 else
4099                         xsnprintf(hex, sizeof(hex), "%s...", abbrev);
4100                 return hex;
4101         }
4102         return sha1_to_hex(sha1);
4103 }
4104
4105 static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
4106 {
4107         int line_termination = opt->line_termination;
4108         int inter_name_termination = line_termination ? '\t' : '\0';
4109
4110         fprintf(opt->file, "%s", diff_line_prefix(opt));
4111         if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
4112                 fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
4113                         diff_unique_abbrev(p->one->sha1, opt->abbrev));
4114                 fprintf(opt->file, "%s ", diff_unique_abbrev(p->two->sha1, opt->abbrev));
4115         }
4116         if (p->score) {
4117                 fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
4118                         inter_name_termination);
4119         } else {
4120                 fprintf(opt->file, "%c%c", p->status, inter_name_termination);
4121         }
4122
4123         if (p->status == DIFF_STATUS_COPIED ||
4124             p->status == DIFF_STATUS_RENAMED) {
4125                 const char *name_a, *name_b;
4126                 name_a = p->one->path;
4127                 name_b = p->two->path;
4128                 strip_prefix(opt->prefix_length, &name_a, &name_b);
4129                 write_name_quoted(name_a, opt->file, inter_name_termination);
4130                 write_name_quoted(name_b, opt->file, line_termination);
4131         } else {
4132                 const char *name_a, *name_b;
4133                 name_a = p->one->mode ? p->one->path : p->two->path;
4134                 name_b = NULL;
4135                 strip_prefix(opt->prefix_length, &name_a, &name_b);
4136                 write_name_quoted(name_a, opt->file, line_termination);
4137         }
4138 }
4139
4140 int diff_unmodified_pair(struct diff_filepair *p)
4141 {
4142         /* This function is written stricter than necessary to support
4143          * the currently implemented transformers, but the idea is to
4144          * let transformers to produce diff_filepairs any way they want,
4145          * and filter and clean them up here before producing the output.
4146          */
4147         struct diff_filespec *one = p->one, *two = p->two;
4148
4149         if (DIFF_PAIR_UNMERGED(p))
4150                 return 0; /* unmerged is interesting */
4151
4152         /* deletion, addition, mode or type change
4153          * and rename are all interesting.
4154          */
4155         if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
4156             DIFF_PAIR_MODE_CHANGED(p) ||
4157             strcmp(one->path, two->path))
4158                 return 0;
4159
4160         /* both are valid and point at the same path.  that is, we are
4161          * dealing with a change.
4162          */
4163         if (one->sha1_valid && two->sha1_valid &&
4164             !hashcmp(one->sha1, two->sha1) &&
4165             !one->dirty_submodule && !two->dirty_submodule)
4166                 return 1; /* no change */
4167         if (!one->sha1_valid && !two->sha1_valid)
4168                 return 1; /* both look at the same file on the filesystem. */
4169         return 0;
4170 }
4171
4172 static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
4173 {
4174         if (diff_unmodified_pair(p))
4175                 return;
4176
4177         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4178             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4179                 return; /* no tree diffs in patch format */
4180
4181         run_diff(p, o);
4182 }
4183
4184 static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
4185                             struct diffstat_t *diffstat)
4186 {
4187         if (diff_unmodified_pair(p))
4188                 return;
4189
4190         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4191             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4192                 return; /* no useful stat for tree diffs */
4193
4194         run_diffstat(p, o, diffstat);
4195 }
4196
4197 static void diff_flush_checkdiff(struct diff_filepair *p,
4198                 struct diff_options *o)
4199 {
4200         if (diff_unmodified_pair(p))
4201                 return;
4202
4203         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4204             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4205                 return; /* nothing to check in tree diffs */
4206
4207         run_checkdiff(p, o);
4208 }
4209
4210 int diff_queue_is_empty(void)
4211 {
4212         struct diff_queue_struct *q = &diff_queued_diff;
4213         int i;
4214         for (i = 0; i < q->nr; i++)
4215                 if (!diff_unmodified_pair(q->queue[i]))
4216                         return 0;
4217         return 1;
4218 }
4219
4220 #if DIFF_DEBUG
4221 void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
4222 {
4223         fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
4224                 x, one ? one : "",
4225                 s->path,
4226                 DIFF_FILE_VALID(s) ? "valid" : "invalid",
4227                 s->mode,
4228                 s->sha1_valid ? sha1_to_hex(s->sha1) : "");
4229         fprintf(stderr, "queue[%d] %s size %lu\n",
4230                 x, one ? one : "",
4231                 s->size);
4232 }
4233
4234 void diff_debug_filepair(const struct diff_filepair *p, int i)
4235 {
4236         diff_debug_filespec(p->one, i, "one");
4237         diff_debug_filespec(p->two, i, "two");
4238         fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
4239                 p->score, p->status ? p->status : '?',
4240                 p->one->rename_used, p->broken_pair);
4241 }
4242
4243 void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
4244 {
4245         int i;
4246         if (msg)
4247                 fprintf(stderr, "%s\n", msg);
4248         fprintf(stderr, "q->nr = %d\n", q->nr);
4249         for (i = 0; i < q->nr; i++) {
4250                 struct diff_filepair *p = q->queue[i];
4251                 diff_debug_filepair(p, i);
4252         }
4253 }
4254 #endif
4255
4256 static void diff_resolve_rename_copy(void)
4257 {
4258         int i;
4259         struct diff_filepair *p;
4260         struct diff_queue_struct *q = &diff_queued_diff;
4261
4262         diff_debug_queue("resolve-rename-copy", q);
4263
4264         for (i = 0; i < q->nr; i++) {
4265                 p = q->queue[i];
4266                 p->status = 0; /* undecided */
4267                 if (DIFF_PAIR_UNMERGED(p))
4268                         p->status = DIFF_STATUS_UNMERGED;
4269                 else if (!DIFF_FILE_VALID(p->one))
4270                         p->status = DIFF_STATUS_ADDED;
4271                 else if (!DIFF_FILE_VALID(p->two))
4272                         p->status = DIFF_STATUS_DELETED;
4273                 else if (DIFF_PAIR_TYPE_CHANGED(p))
4274                         p->status = DIFF_STATUS_TYPE_CHANGED;
4275
4276                 /* from this point on, we are dealing with a pair
4277                  * whose both sides are valid and of the same type, i.e.
4278                  * either in-place edit or rename/copy edit.
4279                  */
4280                 else if (DIFF_PAIR_RENAME(p)) {
4281                         /*
4282                          * A rename might have re-connected a broken
4283                          * pair up, causing the pathnames to be the
4284                          * same again. If so, that's not a rename at
4285                          * all, just a modification..
4286                          *
4287                          * Otherwise, see if this source was used for
4288                          * multiple renames, in which case we decrement
4289                          * the count, and call it a copy.
4290                          */
4291                         if (!strcmp(p->one->path, p->two->path))
4292                                 p->status = DIFF_STATUS_MODIFIED;
4293                         else if (--p->one->rename_used > 0)
4294                                 p->status = DIFF_STATUS_COPIED;
4295                         else
4296                                 p->status = DIFF_STATUS_RENAMED;
4297                 }
4298                 else if (hashcmp(p->one->sha1, p->two->sha1) ||
4299                          p->one->mode != p->two->mode ||
4300                          p->one->dirty_submodule ||
4301                          p->two->dirty_submodule ||
4302                          is_null_sha1(p->one->sha1))
4303                         p->status = DIFF_STATUS_MODIFIED;
4304                 else {
4305                         /* This is a "no-change" entry and should not
4306                          * happen anymore, but prepare for broken callers.
4307                          */
4308                         error("feeding unmodified %s to diffcore",
4309                               p->one->path);
4310                         p->status = DIFF_STATUS_UNKNOWN;
4311                 }
4312         }
4313         diff_debug_queue("resolve-rename-copy done", q);
4314 }
4315
4316 static int check_pair_status(struct diff_filepair *p)
4317 {
4318         switch (p->status) {
4319         case DIFF_STATUS_UNKNOWN:
4320                 return 0;
4321         case 0:
4322                 die("internal error in diff-resolve-rename-copy");
4323         default:
4324                 return 1;
4325         }
4326 }
4327
4328 static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
4329 {
4330         int fmt = opt->output_format;
4331
4332         if (fmt & DIFF_FORMAT_CHECKDIFF)
4333                 diff_flush_checkdiff(p, opt);
4334         else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
4335                 diff_flush_raw(p, opt);
4336         else if (fmt & DIFF_FORMAT_NAME) {
4337                 const char *name_a, *name_b;
4338                 name_a = p->two->path;
4339                 name_b = NULL;
4340                 strip_prefix(opt->prefix_length, &name_a, &name_b);
4341                 write_name_quoted(name_a, opt->file, opt->line_termination);
4342         }
4343 }
4344
4345 static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
4346 {
4347         if (fs->mode)
4348                 fprintf(file, " %s mode %06o ", newdelete, fs->mode);
4349         else
4350                 fprintf(file, " %s ", newdelete);
4351         write_name_quoted(fs->path, file, '\n');
4352 }
4353
4354
4355 static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name,
4356                 const char *line_prefix)
4357 {
4358         if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
4359                 fprintf(file, "%s mode change %06o => %06o%c", line_prefix, p->one->mode,
4360                         p->two->mode, show_name ? ' ' : '\n');
4361                 if (show_name) {
4362                         write_name_quoted(p->two->path, file, '\n');
4363                 }
4364         }
4365 }
4366
4367 static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p,
4368                         const char *line_prefix)
4369 {
4370         char *names = pprint_rename(p->one->path, p->two->path);
4371
4372         fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
4373         free(names);
4374         show_mode_change(file, p, 0, line_prefix);
4375 }
4376
4377 static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
4378 {
4379         FILE *file = opt->file;
4380         const char *line_prefix = diff_line_prefix(opt);
4381
4382         switch(p->status) {
4383         case DIFF_STATUS_DELETED:
4384                 fputs(line_prefix, file);
4385                 show_file_mode_name(file, "delete", p->one);
4386                 break;
4387         case DIFF_STATUS_ADDED:
4388                 fputs(line_prefix, file);
4389                 show_file_mode_name(file, "create", p->two);
4390                 break;
4391         case DIFF_STATUS_COPIED:
4392                 fputs(line_prefix, file);
4393                 show_rename_copy(file, "copy", p, line_prefix);
4394                 break;
4395         case DIFF_STATUS_RENAMED:
4396                 fputs(line_prefix, file);
4397                 show_rename_copy(file, "rename", p, line_prefix);
4398                 break;
4399         default:
4400                 if (p->score) {
4401                         fprintf(file, "%s rewrite ", line_prefix);
4402                         write_name_quoted(p->two->path, file, ' ');
4403                         fprintf(file, "(%d%%)\n", similarity_index(p));
4404                 }
4405                 show_mode_change(file, p, !p->score, line_prefix);
4406                 break;
4407         }
4408 }
4409
4410 struct patch_id_t {
4411         git_SHA_CTX *ctx;
4412         int patchlen;
4413 };
4414
4415 static int remove_space(char *line, int len)
4416 {
4417         int i;
4418         char *dst = line;
4419         unsigned char c;
4420
4421         for (i = 0; i < len; i++)
4422                 if (!isspace((c = line[i])))
4423                         *dst++ = c;
4424
4425         return dst - line;
4426 }
4427
4428 static void patch_id_consume(void *priv, char *line, unsigned long len)
4429 {
4430         struct patch_id_t *data = priv;
4431         int new_len;
4432
4433         /* Ignore line numbers when computing the SHA1 of the patch */
4434         if (starts_with(line, "@@ -"))
4435                 return;
4436
4437         new_len = remove_space(line, len);
4438
4439         git_SHA1_Update(data->ctx, line, new_len);
4440         data->patchlen += new_len;
4441 }
4442
4443 /* returns 0 upon success, and writes result into sha1 */
4444 static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
4445 {
4446         struct diff_queue_struct *q = &diff_queued_diff;
4447         int i;
4448         git_SHA_CTX ctx;
4449         struct patch_id_t data;
4450         char buffer[PATH_MAX * 4 + 20];
4451
4452         git_SHA1_Init(&ctx);
4453         memset(&data, 0, sizeof(struct patch_id_t));
4454         data.ctx = &ctx;
4455
4456         for (i = 0; i < q->nr; i++) {
4457                 xpparam_t xpp;
4458                 xdemitconf_t xecfg;
4459                 mmfile_t mf1, mf2;
4460                 struct diff_filepair *p = q->queue[i];
4461                 int len1, len2;
4462
4463                 memset(&xpp, 0, sizeof(xpp));
4464                 memset(&xecfg, 0, sizeof(xecfg));
4465                 if (p->status == 0)
4466                         return error("internal diff status error");
4467                 if (p->status == DIFF_STATUS_UNKNOWN)
4468                         continue;
4469                 if (diff_unmodified_pair(p))
4470                         continue;
4471                 if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4472                     (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4473                         continue;
4474                 if (DIFF_PAIR_UNMERGED(p))
4475                         continue;
4476
4477                 diff_fill_sha1_info(p->one);
4478                 diff_fill_sha1_info(p->two);
4479                 if (fill_mmfile(&mf1, p->one) < 0 ||
4480                                 fill_mmfile(&mf2, p->two) < 0)
4481                         return error("unable to read files to diff");
4482
4483                 len1 = remove_space(p->one->path, strlen(p->one->path));
4484                 len2 = remove_space(p->two->path, strlen(p->two->path));
4485                 if (p->one->mode == 0)
4486                         len1 = snprintf(buffer, sizeof(buffer),
4487                                         "diff--gita/%.*sb/%.*s"
4488                                         "newfilemode%06o"
4489                                         "---/dev/null"
4490                                         "+++b/%.*s",
4491                                         len1, p->one->path,
4492                                         len2, p->two->path,
4493                                         p->two->mode,
4494                                         len2, p->two->path);
4495                 else if (p->two->mode == 0)
4496                         len1 = snprintf(buffer, sizeof(buffer),
4497                                         "diff--gita/%.*sb/%.*s"
4498                                         "deletedfilemode%06o"
4499                                         "---a/%.*s"
4500                                         "+++/dev/null",
4501                                         len1, p->one->path,
4502                                         len2, p->two->path,
4503                                         p->one->mode,
4504                                         len1, p->one->path);
4505                 else
4506                         len1 = snprintf(buffer, sizeof(buffer),
4507                                         "diff--gita/%.*sb/%.*s"
4508                                         "---a/%.*s"
4509                                         "+++b/%.*s",
4510                                         len1, p->one->path,
4511                                         len2, p->two->path,
4512                                         len1, p->one->path,
4513                                         len2, p->two->path);
4514                 git_SHA1_Update(&ctx, buffer, len1);
4515
4516                 if (diff_filespec_is_binary(p->one) ||
4517                     diff_filespec_is_binary(p->two)) {
4518                         git_SHA1_Update(&ctx, sha1_to_hex(p->one->sha1), 40);
4519                         git_SHA1_Update(&ctx, sha1_to_hex(p->two->sha1), 40);
4520                         continue;
4521                 }
4522
4523                 xpp.flags = 0;
4524                 xecfg.ctxlen = 3;
4525                 xecfg.flags = 0;
4526                 if (xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
4527                                   &xpp, &xecfg))
4528                         return error("unable to generate patch-id diff for %s",
4529                                      p->one->path);
4530         }
4531
4532         git_SHA1_Final(sha1, &ctx);
4533         return 0;
4534 }
4535
4536 int diff_flush_patch_id(struct diff_options *options, unsigned char *sha1)
4537 {
4538         struct diff_queue_struct *q = &diff_queued_diff;
4539         int i;
4540         int result = diff_get_patch_id(options, sha1);
4541
4542         for (i = 0; i < q->nr; i++)
4543                 diff_free_filepair(q->queue[i]);
4544
4545         free(q->queue);
4546         DIFF_QUEUE_CLEAR(q);
4547
4548         return result;
4549 }
4550
4551 static int is_summary_empty(const struct diff_queue_struct *q)
4552 {
4553         int i;
4554
4555         for (i = 0; i < q->nr; i++) {
4556                 const struct diff_filepair *p = q->queue[i];
4557
4558                 switch (p->status) {
4559                 case DIFF_STATUS_DELETED:
4560                 case DIFF_STATUS_ADDED:
4561                 case DIFF_STATUS_COPIED:
4562                 case DIFF_STATUS_RENAMED:
4563                         return 0;
4564                 default:
4565                         if (p->score)
4566                                 return 0;
4567                         if (p->one->mode && p->two->mode &&
4568                             p->one->mode != p->two->mode)
4569                                 return 0;
4570                         break;
4571                 }
4572         }
4573         return 1;
4574 }
4575
4576 static const char rename_limit_warning[] =
4577 "inexact rename detection was skipped due to too many files.";
4578
4579 static const char degrade_cc_to_c_warning[] =
4580 "only found copies from modified paths due to too many files.";
4581
4582 static const char rename_limit_advice[] =
4583 "you may want to set your %s variable to at least "
4584 "%d and retry the command.";
4585
4586 void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
4587 {
4588         if (degraded_cc)
4589                 warning(degrade_cc_to_c_warning);
4590         else if (needed)
4591                 warning(rename_limit_warning);
4592         else
4593                 return;
4594         if (0 < needed && needed < 32767)
4595                 warning(rename_limit_advice, varname, needed);
4596 }
4597
4598 void diff_flush(struct diff_options *options)
4599 {
4600         struct diff_queue_struct *q = &diff_queued_diff;
4601         int i, output_format = options->output_format;
4602         int separator = 0;
4603         int dirstat_by_line = 0;
4604
4605         /*
4606          * Order: raw, stat, summary, patch
4607          * or:    name/name-status/checkdiff (other bits clear)
4608          */
4609         if (!q->nr)
4610                 goto free_queue;
4611
4612         if (output_format & (DIFF_FORMAT_RAW |
4613                              DIFF_FORMAT_NAME |
4614                              DIFF_FORMAT_NAME_STATUS |
4615                              DIFF_FORMAT_CHECKDIFF)) {
4616                 for (i = 0; i < q->nr; i++) {
4617                         struct diff_filepair *p = q->queue[i];
4618                         if (check_pair_status(p))
4619                                 flush_one_pair(p, options);
4620                 }
4621                 separator++;
4622         }
4623
4624         if (output_format & DIFF_FORMAT_DIRSTAT && DIFF_OPT_TST(options, DIRSTAT_BY_LINE))
4625                 dirstat_by_line = 1;
4626
4627         if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
4628             dirstat_by_line) {
4629                 struct diffstat_t diffstat;
4630
4631                 memset(&diffstat, 0, sizeof(struct diffstat_t));
4632                 for (i = 0; i < q->nr; i++) {
4633                         struct diff_filepair *p = q->queue[i];
4634                         if (check_pair_status(p))
4635                                 diff_flush_stat(p, options, &diffstat);
4636                 }
4637                 if (output_format & DIFF_FORMAT_NUMSTAT)
4638                         show_numstat(&diffstat, options);
4639                 if (output_format & DIFF_FORMAT_DIFFSTAT)
4640                         show_stats(&diffstat, options);
4641                 if (output_format & DIFF_FORMAT_SHORTSTAT)
4642                         show_shortstats(&diffstat, options);
4643                 if (output_format & DIFF_FORMAT_DIRSTAT && dirstat_by_line)
4644                         show_dirstat_by_line(&diffstat, options);
4645                 free_diffstat_info(&diffstat);
4646                 separator++;
4647         }
4648         if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
4649                 show_dirstat(options);
4650
4651         if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
4652                 for (i = 0; i < q->nr; i++) {
4653                         diff_summary(options, q->queue[i]);
4654                 }
4655                 separator++;
4656         }
4657
4658         if (output_format & DIFF_FORMAT_NO_OUTPUT &&
4659             DIFF_OPT_TST(options, EXIT_WITH_STATUS) &&
4660             DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4661                 /*
4662                  * run diff_flush_patch for the exit status. setting
4663                  * options->file to /dev/null should be safe, because we
4664                  * aren't supposed to produce any output anyway.
4665                  */
4666                 if (options->close_file)
4667                         fclose(options->file);
4668                 options->file = fopen("/dev/null", "w");
4669                 if (!options->file)
4670                         die_errno("Could not open /dev/null");
4671                 options->close_file = 1;
4672                 for (i = 0; i < q->nr; i++) {
4673                         struct diff_filepair *p = q->queue[i];
4674                         if (check_pair_status(p))
4675                                 diff_flush_patch(p, options);
4676                         if (options->found_changes)
4677                                 break;
4678                 }
4679         }
4680
4681         if (output_format & DIFF_FORMAT_PATCH) {
4682                 if (separator) {
4683                         fprintf(options->file, "%s%c",
4684                                 diff_line_prefix(options),
4685                                 options->line_termination);
4686                         if (options->stat_sep) {
4687                                 /* attach patch instead of inline */
4688                                 fputs(options->stat_sep, options->file);
4689                         }
4690                 }
4691
4692                 for (i = 0; i < q->nr; i++) {
4693                         struct diff_filepair *p = q->queue[i];
4694                         if (check_pair_status(p))
4695                                 diff_flush_patch(p, options);
4696                 }
4697         }
4698
4699         if (output_format & DIFF_FORMAT_CALLBACK)
4700                 options->format_callback(q, options, options->format_callback_data);
4701
4702         for (i = 0; i < q->nr; i++)
4703                 diff_free_filepair(q->queue[i]);
4704 free_queue:
4705         free(q->queue);
4706         DIFF_QUEUE_CLEAR(q);
4707         if (options->close_file)
4708                 fclose(options->file);
4709
4710         /*
4711          * Report the content-level differences with HAS_CHANGES;
4712          * diff_addremove/diff_change does not set the bit when
4713          * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
4714          */
4715         if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4716                 if (options->found_changes)
4717                         DIFF_OPT_SET(options, HAS_CHANGES);
4718                 else
4719                         DIFF_OPT_CLR(options, HAS_CHANGES);
4720         }
4721 }
4722
4723 static int match_filter(const struct diff_options *options, const struct diff_filepair *p)
4724 {
4725         return (((p->status == DIFF_STATUS_MODIFIED) &&
4726                  ((p->score &&
4727                    filter_bit_tst(DIFF_STATUS_FILTER_BROKEN, options)) ||
4728                   (!p->score &&
4729                    filter_bit_tst(DIFF_STATUS_MODIFIED, options)))) ||
4730                 ((p->status != DIFF_STATUS_MODIFIED) &&
4731                  filter_bit_tst(p->status, options)));
4732 }
4733
4734 static void diffcore_apply_filter(struct diff_options *options)
4735 {
4736         int i;
4737         struct diff_queue_struct *q = &diff_queued_diff;
4738         struct diff_queue_struct outq;
4739
4740         DIFF_QUEUE_CLEAR(&outq);
4741
4742         if (!options->filter)
4743                 return;
4744
4745         if (filter_bit_tst(DIFF_STATUS_FILTER_AON, options)) {
4746                 int found;
4747                 for (i = found = 0; !found && i < q->nr; i++) {
4748                         if (match_filter(options, q->queue[i]))
4749                                 found++;
4750                 }
4751                 if (found)
4752                         return;
4753
4754                 /* otherwise we will clear the whole queue
4755                  * by copying the empty outq at the end of this
4756                  * function, but first clear the current entries
4757                  * in the queue.
4758                  */
4759                 for (i = 0; i < q->nr; i++)
4760                         diff_free_filepair(q->queue[i]);
4761         }
4762         else {
4763                 /* Only the matching ones */
4764                 for (i = 0; i < q->nr; i++) {
4765                         struct diff_filepair *p = q->queue[i];
4766                         if (match_filter(options, p))
4767                                 diff_q(&outq, p);
4768                         else
4769                                 diff_free_filepair(p);
4770                 }
4771         }
4772         free(q->queue);
4773         *q = outq;
4774 }
4775
4776 /* Check whether two filespecs with the same mode and size are identical */
4777 static int diff_filespec_is_identical(struct diff_filespec *one,
4778                                       struct diff_filespec *two)
4779 {
4780         if (S_ISGITLINK(one->mode))
4781                 return 0;
4782         if (diff_populate_filespec(one, 0))
4783                 return 0;
4784         if (diff_populate_filespec(two, 0))
4785                 return 0;
4786         return !memcmp(one->data, two->data, one->size);
4787 }
4788
4789 static int diff_filespec_check_stat_unmatch(struct diff_filepair *p)
4790 {
4791         if (p->done_skip_stat_unmatch)
4792                 return p->skip_stat_unmatch_result;
4793
4794         p->done_skip_stat_unmatch = 1;
4795         p->skip_stat_unmatch_result = 0;
4796         /*
4797          * 1. Entries that come from stat info dirtiness
4798          *    always have both sides (iow, not create/delete),
4799          *    one side of the object name is unknown, with
4800          *    the same mode and size.  Keep the ones that
4801          *    do not match these criteria.  They have real
4802          *    differences.
4803          *
4804          * 2. At this point, the file is known to be modified,
4805          *    with the same mode and size, and the object
4806          *    name of one side is unknown.  Need to inspect
4807          *    the identical contents.
4808          */
4809         if (!DIFF_FILE_VALID(p->one) || /* (1) */
4810             !DIFF_FILE_VALID(p->two) ||
4811             (p->one->sha1_valid && p->two->sha1_valid) ||
4812             (p->one->mode != p->two->mode) ||
4813             diff_populate_filespec(p->one, CHECK_SIZE_ONLY) ||
4814             diff_populate_filespec(p->two, CHECK_SIZE_ONLY) ||
4815             (p->one->size != p->two->size) ||
4816             !diff_filespec_is_identical(p->one, p->two)) /* (2) */
4817                 p->skip_stat_unmatch_result = 1;
4818         return p->skip_stat_unmatch_result;
4819 }
4820
4821 static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
4822 {
4823         int i;
4824         struct diff_queue_struct *q = &diff_queued_diff;
4825         struct diff_queue_struct outq;
4826         DIFF_QUEUE_CLEAR(&outq);
4827
4828         for (i = 0; i < q->nr; i++) {
4829                 struct diff_filepair *p = q->queue[i];
4830
4831                 if (diff_filespec_check_stat_unmatch(p))
4832                         diff_q(&outq, p);
4833                 else {
4834                         /*
4835                          * The caller can subtract 1 from skip_stat_unmatch
4836                          * to determine how many paths were dirty only
4837                          * due to stat info mismatch.
4838                          */
4839                         if (!DIFF_OPT_TST(diffopt, NO_INDEX))
4840                                 diffopt->skip_stat_unmatch++;
4841                         diff_free_filepair(p);
4842                 }
4843         }
4844         free(q->queue);
4845         *q = outq;
4846 }
4847
4848 static int diffnamecmp(const void *a_, const void *b_)
4849 {
4850         const struct diff_filepair *a = *((const struct diff_filepair **)a_);
4851         const struct diff_filepair *b = *((const struct diff_filepair **)b_);
4852         const char *name_a, *name_b;
4853
4854         name_a = a->one ? a->one->path : a->two->path;
4855         name_b = b->one ? b->one->path : b->two->path;
4856         return strcmp(name_a, name_b);
4857 }
4858
4859 void diffcore_fix_diff_index(struct diff_options *options)
4860 {
4861         struct diff_queue_struct *q = &diff_queued_diff;
4862         qsort(q->queue, q->nr, sizeof(q->queue[0]), diffnamecmp);
4863 }
4864
4865 void diffcore_std(struct diff_options *options)
4866 {
4867         /* NOTE please keep the following in sync with diff_tree_combined() */
4868         if (options->skip_stat_unmatch)
4869                 diffcore_skip_stat_unmatch(options);
4870         if (!options->found_follow) {
4871                 /* See try_to_follow_renames() in tree-diff.c */
4872                 if (options->break_opt != -1)
4873                         diffcore_break(options->break_opt);
4874                 if (options->detect_rename)
4875                         diffcore_rename(options);
4876                 if (options->break_opt != -1)
4877                         diffcore_merge_broken();
4878         }
4879         if (options->pickaxe)
4880                 diffcore_pickaxe(options);
4881         if (options->orderfile)
4882                 diffcore_order(options->orderfile);
4883         if (!options->found_follow)
4884                 /* See try_to_follow_renames() in tree-diff.c */
4885                 diff_resolve_rename_copy();
4886         diffcore_apply_filter(options);
4887
4888         if (diff_queued_diff.nr && !DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4889                 DIFF_OPT_SET(options, HAS_CHANGES);
4890         else
4891                 DIFF_OPT_CLR(options, HAS_CHANGES);
4892
4893         options->found_follow = 0;
4894 }
4895
4896 int diff_result_code(struct diff_options *opt, int status)
4897 {
4898         int result = 0;
4899
4900         diff_warn_rename_limit("diff.renameLimit",
4901                                opt->needed_rename_limit,
4902                                opt->degraded_cc_to_c);
4903         if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4904             !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
4905                 return status;
4906         if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
4907             DIFF_OPT_TST(opt, HAS_CHANGES))
4908                 result |= 01;
4909         if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
4910             DIFF_OPT_TST(opt, CHECK_FAILED))
4911                 result |= 02;
4912         return result;
4913 }
4914
4915 int diff_can_quit_early(struct diff_options *opt)
4916 {
4917         return (DIFF_OPT_TST(opt, QUICK) &&
4918                 !opt->filter &&
4919                 DIFF_OPT_TST(opt, HAS_CHANGES));
4920 }
4921
4922 /*
4923  * Shall changes to this submodule be ignored?
4924  *
4925  * Submodule changes can be configured to be ignored separately for each path,
4926  * but that configuration can be overridden from the command line.
4927  */
4928 static int is_submodule_ignored(const char *path, struct diff_options *options)
4929 {
4930         int ignored = 0;
4931         unsigned orig_flags = options->flags;
4932         if (!DIFF_OPT_TST(options, OVERRIDE_SUBMODULE_CONFIG))
4933                 set_diffopt_flags_from_submodule_config(options, path);
4934         if (DIFF_OPT_TST(options, IGNORE_SUBMODULES))
4935                 ignored = 1;
4936         options->flags = orig_flags;
4937         return ignored;
4938 }
4939
4940 void diff_addremove(struct diff_options *options,
4941                     int addremove, unsigned mode,
4942                     const unsigned char *sha1,
4943                     int sha1_valid,
4944                     const char *concatpath, unsigned dirty_submodule)
4945 {
4946         struct diff_filespec *one, *two;
4947
4948         if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
4949                 return;
4950
4951         /* This may look odd, but it is a preparation for
4952          * feeding "there are unchanged files which should
4953          * not produce diffs, but when you are doing copy
4954          * detection you would need them, so here they are"
4955          * entries to the diff-core.  They will be prefixed
4956          * with something like '=' or '*' (I haven't decided
4957          * which but should not make any difference).
4958          * Feeding the same new and old to diff_change()
4959          * also has the same effect.
4960          * Before the final output happens, they are pruned after
4961          * merged into rename/copy pairs as appropriate.
4962          */
4963         if (DIFF_OPT_TST(options, REVERSE_DIFF))
4964                 addremove = (addremove == '+' ? '-' :
4965                              addremove == '-' ? '+' : addremove);
4966
4967         if (options->prefix &&
4968             strncmp(concatpath, options->prefix, options->prefix_length))
4969                 return;
4970
4971         one = alloc_filespec(concatpath);
4972         two = alloc_filespec(concatpath);
4973
4974         if (addremove != '+')
4975                 fill_filespec(one, sha1, sha1_valid, mode);
4976         if (addremove != '-') {
4977                 fill_filespec(two, sha1, sha1_valid, mode);
4978                 two->dirty_submodule = dirty_submodule;
4979         }
4980
4981         diff_queue(&diff_queued_diff, one, two);
4982         if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
4983                 DIFF_OPT_SET(options, HAS_CHANGES);
4984 }
4985
4986 void diff_change(struct diff_options *options,
4987                  unsigned old_mode, unsigned new_mode,
4988                  const unsigned char *old_sha1,
4989                  const unsigned char *new_sha1,
4990                  int old_sha1_valid, int new_sha1_valid,
4991                  const char *concatpath,
4992                  unsigned old_dirty_submodule, unsigned new_dirty_submodule)
4993 {
4994         struct diff_filespec *one, *two;
4995         struct diff_filepair *p;
4996
4997         if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
4998             is_submodule_ignored(concatpath, options))
4999                 return;
5000
5001         if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
5002                 unsigned tmp;
5003                 const unsigned char *tmp_c;
5004                 tmp = old_mode; old_mode = new_mode; new_mode = tmp;
5005                 tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
5006                 tmp = old_sha1_valid; old_sha1_valid = new_sha1_valid;
5007                         new_sha1_valid = tmp;
5008                 tmp = old_dirty_submodule; old_dirty_submodule = new_dirty_submodule;
5009                         new_dirty_submodule = tmp;
5010         }
5011
5012         if (options->prefix &&
5013             strncmp(concatpath, options->prefix, options->prefix_length))
5014                 return;
5015
5016         one = alloc_filespec(concatpath);
5017         two = alloc_filespec(concatpath);
5018         fill_filespec(one, old_sha1, old_sha1_valid, old_mode);
5019         fill_filespec(two, new_sha1, new_sha1_valid, new_mode);
5020         one->dirty_submodule = old_dirty_submodule;
5021         two->dirty_submodule = new_dirty_submodule;
5022         p = diff_queue(&diff_queued_diff, one, two);
5023
5024         if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
5025                 return;
5026
5027         if (DIFF_OPT_TST(options, QUICK) && options->skip_stat_unmatch &&
5028             !diff_filespec_check_stat_unmatch(p))
5029                 return;
5030
5031         DIFF_OPT_SET(options, HAS_CHANGES);
5032 }
5033
5034 struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
5035 {
5036         struct diff_filepair *pair;
5037         struct diff_filespec *one, *two;
5038
5039         if (options->prefix &&
5040             strncmp(path, options->prefix, options->prefix_length))
5041                 return NULL;
5042
5043         one = alloc_filespec(path);
5044         two = alloc_filespec(path);
5045         pair = diff_queue(&diff_queued_diff, one, two);
5046         pair->is_unmerged = 1;
5047         return pair;
5048 }
5049
5050 static char *run_textconv(const char *pgm, struct diff_filespec *spec,
5051                 size_t *outsize)
5052 {
5053         struct diff_tempfile *temp;
5054         const char *argv[3];
5055         const char **arg = argv;
5056         struct child_process child = CHILD_PROCESS_INIT;
5057         struct strbuf buf = STRBUF_INIT;
5058         int err = 0;
5059
5060         temp = prepare_temp_file(spec->path, spec);
5061         *arg++ = pgm;
5062         *arg++ = temp->name;
5063         *arg = NULL;
5064
5065         child.use_shell = 1;
5066         child.argv = argv;
5067         child.out = -1;
5068         if (start_command(&child)) {
5069                 remove_tempfile();
5070                 return NULL;
5071         }
5072
5073         if (strbuf_read(&buf, child.out, 0) < 0)
5074                 err = error("error reading from textconv command '%s'", pgm);
5075         close(child.out);
5076
5077         if (finish_command(&child) || err) {
5078                 strbuf_release(&buf);
5079                 remove_tempfile();
5080                 return NULL;
5081         }
5082         remove_tempfile();
5083
5084         return strbuf_detach(&buf, outsize);
5085 }
5086
5087 size_t fill_textconv(struct userdiff_driver *driver,
5088                      struct diff_filespec *df,
5089                      char **outbuf)
5090 {
5091         size_t size;
5092
5093         if (!driver || !driver->textconv) {
5094                 if (!DIFF_FILE_VALID(df)) {
5095                         *outbuf = "";
5096                         return 0;
5097                 }
5098                 if (diff_populate_filespec(df, 0))
5099                         die("unable to read files to diff");
5100                 *outbuf = df->data;
5101                 return df->size;
5102         }
5103
5104         if (driver->textconv_cache && df->sha1_valid) {
5105                 *outbuf = notes_cache_get(driver->textconv_cache, df->sha1,
5106                                           &size);
5107                 if (*outbuf)
5108                         return size;
5109         }
5110
5111         *outbuf = run_textconv(driver->textconv, df, &size);
5112         if (!*outbuf)
5113                 die("unable to read files to diff");
5114
5115         if (driver->textconv_cache && df->sha1_valid) {
5116                 /* ignore errors, as we might be in a readonly repository */
5117                 notes_cache_put(driver->textconv_cache, df->sha1, *outbuf,
5118                                 size);
5119                 /*
5120                  * we could save up changes and flush them all at the end,
5121                  * but we would need an extra call after all diffing is done.
5122                  * Since generating a cache entry is the slow path anyway,
5123                  * this extra overhead probably isn't a big deal.
5124                  */
5125                 notes_cache_write(driver->textconv_cache);
5126         }
5127
5128         return size;
5129 }
5130
5131 void setup_diff_pager(struct diff_options *opt)
5132 {
5133         /*
5134          * If the user asked for our exit code, then either they want --quiet
5135          * or --exit-code. We should definitely not bother with a pager in the
5136          * former case, as we will generate no output. Since we still properly
5137          * report our exit code even when a pager is run, we _could_ run a
5138          * pager with --exit-code. But since we have not done so historically,
5139          * and because it is easy to find people oneline advising "git diff
5140          * --exit-code" in hooks and other scripts, we do not do so.
5141          */
5142         if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
5143             check_pager_config("diff") != 0)
5144                 setup_pager();
5145 }