diff.c

   1 /*
   2  * Copyright (C) 2005 Junio C Hamano
   3  */
   4 #include "cache.h"
   5 #include "quote.h"
   6 #include "diff.h"
   7 #include "diffcore.h"
   8 #include "delta.h"
   9 #include "xdiff-interface.h"
  10 #include "color.h"
  11 #include "attr.h"
  12 #include "run-command.h"
  13 #include "utf8.h"
  14 #include "userdiff.h"
  15
  16 #ifdef NO_FAST_WORKING_DIRECTORY
  17 #define FAST_WORKING_DIRECTORY 0
  18 #else
  19 #define FAST_WORKING_DIRECTORY 1
  20 #endif
  21
  22 static int diff_detect_rename_default;
  23 static int diff_rename_limit_default = 200;
  24 static int diff_suppress_blank_empty;
  25 int diff_use_color_default = -1;
  26 static const char *external_diff_cmd_cfg;
  27 int diff_auto_refresh_index = 1;
  28 static int diff_mnemonic_prefix;
  29
  30 static char diff_colors[][COLOR_MAXLEN] = {
  31         "\033[m",       /* reset */
  32         "",             /* PLAIN (normal) */
  33         "\033[1m",      /* METAINFO (bold) */
  34         "\033[36m",     /* FRAGINFO (cyan) */
  35         "\033[31m",     /* OLD (red) */
  36         "\033[32m",     /* NEW (green) */
  37         "\033[33m",     /* COMMIT (yellow) */
  38         "\033[41m",     /* WHITESPACE (red background) */
  39 };
  40
  41 static int parse_diff_color_slot(const char *var, int ofs)
  42 {
  43         if (!strcasecmp(var+ofs, "plain"))
  44                 return DIFF_PLAIN;
  45         if (!strcasecmp(var+ofs, "meta"))
  46                 return DIFF_METAINFO;
  47         if (!strcasecmp(var+ofs, "frag"))
  48                 return DIFF_FRAGINFO;
  49         if (!strcasecmp(var+ofs, "old"))
  50                 return DIFF_FILE_OLD;
  51         if (!strcasecmp(var+ofs, "new"))
  52                 return DIFF_FILE_NEW;
  53         if (!strcasecmp(var+ofs, "commit"))
  54                 return DIFF_COMMIT;
  55         if (!strcasecmp(var+ofs, "whitespace"))
  56                 return DIFF_WHITESPACE;
  57         die("bad config variable '%s'", var);
  58 }
  59
  60 /*
  61  * These are to give UI layer defaults.
  62  * The core-level commands such as git-diff-files should
  63  * never be affected by the setting of diff.renames
  64  * the user happens to have in the configuration file.
  65  */
  66 int git_diff_ui_config(const char *var, const char *value, void *cb)
  67 {
  68         if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
  69                 diff_use_color_default = git_config_colorbool(var, value, -1);
  70                 return 0;
  71         }
  72         if (!strcmp(var, "diff.renames")) {
  73                 if (!value)
  74                         diff_detect_rename_default = DIFF_DETECT_RENAME;
  75                 else if (!strcasecmp(value, "copies") ||
  76                          !strcasecmp(value, "copy"))
  77                         diff_detect_rename_default = DIFF_DETECT_COPY;
  78                 else if (git_config_bool(var,value))
  79                         diff_detect_rename_default = DIFF_DETECT_RENAME;
  80                 return 0;
  81         }
  82         if (!strcmp(var, "diff.autorefreshindex")) {
  83                 diff_auto_refresh_index = git_config_bool(var, value);
  84                 return 0;
  85         }
  86         if (!strcmp(var, "diff.mnemonicprefix")) {
  87                 diff_mnemonic_prefix = git_config_bool(var, value);
  88                 return 0;
  89         }
  90         if (!strcmp(var, "diff.external"))
  91                 return git_config_string(&external_diff_cmd_cfg, var, value);
  92
  93         switch (userdiff_config_porcelain(var, value)) {
  94                 case 0: break;
  95                 case -1: return -1;
  96                 default: return 0;
  97         }
  98
  99         return git_diff_basic_config(var, value, cb);
 100 }
 101
 102 int git_diff_basic_config(const char *var, const char *value, void *cb)
 103 {
 104         if (!strcmp(var, "diff.renamelimit")) {
 105                 diff_rename_limit_default = git_config_int(var, value);
 106                 return 0;
 107         }
 108
 109         if (!prefixcmp(var, "diff.color.") || !prefixcmp(var, "color.diff.")) {
 110                 int slot = parse_diff_color_slot(var, 11);
 111                 if (!value)
 112                         return config_error_nonbool(var);
 113                 color_parse(value, var, diff_colors[slot]);
 114                 return 0;
 115         }
 116
 117         /* like GNU diff's --suppress-blank-empty option  */
 118         if (!strcmp(var, "diff.suppress-blank-empty")) {
 119                 diff_suppress_blank_empty = git_config_bool(var, value);
 120                 return 0;
 121         }
 122
 123         switch (userdiff_config_basic(var, value)) {
 124                 case 0: break;
 125                 case -1: return -1;
 126                 default: return 0;
 127         }
 128
 129         return git_color_default_config(var, value, cb);
 130 }
 131
 132 static char *quote_two(const char *one, const char *two)
 133 {
 134         int need_one = quote_c_style(one, NULL, NULL, 1);
 135         int need_two = quote_c_style(two, NULL, NULL, 1);
 136         struct strbuf res = STRBUF_INIT;
 137
 138         if (need_one + need_two) {
 139                 strbuf_addch(&res, '"');
 140                 quote_c_style(one, &res, NULL, 1);
 141                 quote_c_style(two, &res, NULL, 1);
 142                 strbuf_addch(&res, '"');
 143         } else {
 144                 strbuf_addstr(&res, one);
 145                 strbuf_addstr(&res, two);
 146         }
 147         return strbuf_detach(&res, NULL);
 148 }
 149
 150 static const char *external_diff(void)
 151 {
 152         static const char *external_diff_cmd = NULL;
 153         static int done_preparing = 0;
 154
 155         if (done_preparing)
 156                 return external_diff_cmd;
 157         external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 158         if (!external_diff_cmd)
 159                 external_diff_cmd = external_diff_cmd_cfg;
 160         done_preparing = 1;
 161         return external_diff_cmd;
 162 }
 163
 164 static struct diff_tempfile {
 165         const char *name; /* filename external diff should read from */
 166         char hex[41];
 167         char mode[10];
 168         char tmp_path[PATH_MAX];
 169 } diff_temp[2];
 170
 171 static int count_lines(const char *data, int size)
 172 {
 173         int count, ch, completely_empty = 1, nl_just_seen = 0;
 174         count = 0;
 175         while (0 < size--) {
 176                 ch = *data++;
 177                 if (ch == '\n') {
 178                         count++;
 179                         nl_just_seen = 1;
 180                         completely_empty = 0;
 181                 }
 182                 else {
 183                         nl_just_seen = 0;
 184                         completely_empty = 0;
 185                 }
 186         }
 187         if (completely_empty)
 188                 return 0;
 189         if (!nl_just_seen)
 190                 count++; /* no trailing newline */
 191         return count;
 192 }
 193
 194 static void print_line_count(FILE *file, int count)
 195 {
 196         switch (count) {
 197         case 0:
 198                 fprintf(file, "0,0");
 199                 break;
 200         case 1:
 201                 fprintf(file, "1");
 202                 break;
 203         default:
 204                 fprintf(file, "1,%d", count);
 205                 break;
 206         }
 207 }
 208
 209 static void copy_file_with_prefix(FILE *file,
 210                                   int prefix, const char *data, int size,
 211                                   const char *set, const char *reset)
 212 {
 213         int ch, nl_just_seen = 1;
 214         while (0 < size--) {
 215                 ch = *data++;
 216                 if (nl_just_seen) {
 217                         fputs(set, file);
 218                         putc(prefix, file);
 219                 }
 220                 if (ch == '\n') {
 221                         nl_just_seen = 1;
 222                         fputs(reset, file);
 223                 } else
 224                         nl_just_seen = 0;
 225                 putc(ch, file);
 226         }
 227         if (!nl_just_seen)
 228                 fprintf(file, "%s\n\\ No newline at end of file\n", reset);
 229 }
 230
 231 static void emit_rewrite_diff(const char *name_a,
 232                               const char *name_b,
 233                               struct diff_filespec *one,
 234                               struct diff_filespec *two,
 235                               struct diff_options *o)
 236 {
 237         int lc_a, lc_b;
 238         int color_diff = DIFF_OPT_TST(o, COLOR_DIFF);
 239         const char *name_a_tab, *name_b_tab;
 240         const char *metainfo = diff_get_color(color_diff, DIFF_METAINFO);
 241         const char *fraginfo = diff_get_color(color_diff, DIFF_FRAGINFO);
 242         const char *old = diff_get_color(color_diff, DIFF_FILE_OLD);
 243         const char *new = diff_get_color(color_diff, DIFF_FILE_NEW);
 244         const char *reset = diff_get_color(color_diff, DIFF_RESET);
 245         static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
 246         const char *a_prefix, *b_prefix;
 247
 248         if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
 249                 a_prefix = o->b_prefix;
 250                 b_prefix = o->a_prefix;
 251         } else {
 252                 a_prefix = o->a_prefix;
 253                 b_prefix = o->b_prefix;
 254         }
 255
 256         name_a += (*name_a == '/');
 257         name_b += (*name_b == '/');
 258         name_a_tab = strchr(name_a, ' ') ? "\t" : "";
 259         name_b_tab = strchr(name_b, ' ') ? "\t" : "";
 260
 261         strbuf_reset(&a_name);
 262         strbuf_reset(&b_name);
 263         quote_two_c_style(&a_name, a_prefix, name_a, 0);
 264         quote_two_c_style(&b_name, b_prefix, name_b, 0);
 265
 266         diff_populate_filespec(one, 0);
 267         diff_populate_filespec(two, 0);
 268         lc_a = count_lines(one->data, one->size);
 269         lc_b = count_lines(two->data, two->size);
 270         fprintf(o->file,
 271                 "%s--- %s%s%s\n%s+++ %s%s%s\n%s@@ -",
 272                 metainfo, a_name.buf, name_a_tab, reset,
 273                 metainfo, b_name.buf, name_b_tab, reset, fraginfo);
 274         print_line_count(o->file, lc_a);
 275         fprintf(o->file, " +");
 276         print_line_count(o->file, lc_b);
 277         fprintf(o->file, " @@%s\n", reset);
 278         if (lc_a)
 279                 copy_file_with_prefix(o->file, '-', one->data, one->size, old, reset);
 280         if (lc_b)
 281                 copy_file_with_prefix(o->file, '+', two->data, two->size, new, reset);
 282 }
 283
 284 static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 285 {
 286         if (!DIFF_FILE_VALID(one)) {
 287                 mf->ptr = (char *)""; /* does not matter */
 288                 mf->size = 0;
 289                 return 0;
 290         }
 291         else if (diff_populate_filespec(one, 0))
 292                 return -1;
 293         mf->ptr = one->data;
 294         mf->size = one->size;
 295         return 0;
 296 }
 297
 298 struct diff_words_buffer {
 299         mmfile_t text;
 300         long alloc;
 301         long current; /* output pointer */
 302         int suppressed_newline;
 303 };
 304
 305 static void diff_words_append(char *line, unsigned long len,
 306                 struct diff_words_buffer *buffer)
 307 {
 308         if (buffer->text.size + len > buffer->alloc) {
 309                 buffer->alloc = (buffer->text.size + len) * 3 / 2;
 310                 buffer->text.ptr = xrealloc(buffer->text.ptr, buffer->alloc);
 311         }
 312         line++;
 313         len--;
 314         memcpy(buffer->text.ptr + buffer->text.size, line, len);
 315         buffer->text.size += len;
 316 }
 317
 318 struct diff_words_data {
 319         struct diff_words_buffer minus, plus;
 320         FILE *file;
 321 };
 322
 323 static void print_word(FILE *file, struct diff_words_buffer *buffer, int len, int color,
 324                 int suppress_newline)
 325 {
 326         const char *ptr;
 327         int eol = 0;
 328
 329         if (len == 0)
 330                 return;
 331
 332         ptr  = buffer->text.ptr + buffer->current;
 333         buffer->current += len;
 334
 335         if (ptr[len - 1] == '\n') {
 336                 eol = 1;
 337                 len--;
 338         }
 339
 340         fputs(diff_get_color(1, color), file);
 341         fwrite(ptr, len, 1, file);
 342         fputs(diff_get_color(1, DIFF_RESET), file);
 343
 344         if (eol) {
 345                 if (suppress_newline)
 346                         buffer->suppressed_newline = 1;
 347                 else
 348                         putc('\n', file);
 349         }
 350 }
 351
 352 static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
 353 {
 354         struct diff_words_data *diff_words = priv;
 355
 356         if (diff_words->minus.suppressed_newline) {
 357                 if (line[0] != '+')
 358                         putc('\n', diff_words->file);
 359                 diff_words->minus.suppressed_newline = 0;
 360         }
 361
 362         len--;
 363         switch (line[0]) {
 364                 case '-':
 365                         print_word(diff_words->file,
 366                                    &diff_words->minus, len, DIFF_FILE_OLD, 1);
 367                         break;
 368                 case '+':
 369                         print_word(diff_words->file,
 370                                    &diff_words->plus, len, DIFF_FILE_NEW, 0);
 371                         break;
 372                 case ' ':
 373                         print_word(diff_words->file,
 374                                    &diff_words->plus, len, DIFF_PLAIN, 0);
 375                         diff_words->minus.current += len;
 376                         break;
 377         }
 378 }
 379
 380 /* this executes the word diff on the accumulated buffers */
 381 static void diff_words_show(struct diff_words_data *diff_words)
 382 {
 383         xpparam_t xpp;
 384         xdemitconf_t xecfg;
 385         xdemitcb_t ecb;
 386         mmfile_t minus, plus;
 387         int i;
 388
 389         memset(&xecfg, 0, sizeof(xecfg));
 390         minus.size = diff_words->minus.text.size;
 391         minus.ptr = xmalloc(minus.size);
 392         memcpy(minus.ptr, diff_words->minus.text.ptr, minus.size);
 393         for (i = 0; i < minus.size; i++)
 394                 if (isspace(minus.ptr[i]))
 395                         minus.ptr[i] = '\n';
 396         diff_words->minus.current = 0;
 397
 398         plus.size = diff_words->plus.text.size;
 399         plus.ptr = xmalloc(plus.size);
 400         memcpy(plus.ptr, diff_words->plus.text.ptr, plus.size);
 401         for (i = 0; i < plus.size; i++)
 402                 if (isspace(plus.ptr[i]))
 403                         plus.ptr[i] = '\n';
 404         diff_words->plus.current = 0;
 405
 406         xpp.flags = XDF_NEED_MINIMAL;
 407         xecfg.ctxlen = diff_words->minus.alloc + diff_words->plus.alloc;
 408         xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
 409                       &xpp, &xecfg, &ecb);
 410         free(minus.ptr);
 411         free(plus.ptr);
 412         diff_words->minus.text.size = diff_words->plus.text.size = 0;
 413
 414         if (diff_words->minus.suppressed_newline) {
 415                 putc('\n', diff_words->file);
 416                 diff_words->minus.suppressed_newline = 0;
 417         }
 418 }
 419
 420 typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
 421
 422 struct emit_callback {
 423         int nparents, color_diff;
 424         unsigned ws_rule;
 425         sane_truncate_fn truncate;
 426         const char **label_path;
 427         struct diff_words_data *diff_words;
 428         int *found_changesp;
 429         FILE *file;
 430 };
 431
 432 static void free_diff_words_data(struct emit_callback *ecbdata)
 433 {
 434         if (ecbdata->diff_words) {
 435                 /* flush buffers */
 436                 if (ecbdata->diff_words->minus.text.size ||
 437                                 ecbdata->diff_words->plus.text.size)
 438                         diff_words_show(ecbdata->diff_words);
 439
 440                 free (ecbdata->diff_words->minus.text.ptr);
 441                 free (ecbdata->diff_words->plus.text.ptr);
 442                 free(ecbdata->diff_words);
 443                 ecbdata->diff_words = NULL;
 444         }
 445 }
 446
 447 const char *diff_get_color(int diff_use_color, enum color_diff ix)
 448 {
 449         if (diff_use_color)
 450                 return diff_colors[ix];
 451         return "";
 452 }
 453
 454 static void emit_line(FILE *file, const char *set, const char *reset, const char *line, int len)
 455 {
 456         int has_trailing_newline, has_trailing_carriage_return;
 457
 458         has_trailing_newline = (len > 0 && line[len-1] == '\n');
 459         if (has_trailing_newline)
 460                 len--;
 461         has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
 462         if (has_trailing_carriage_return)
 463                 len--;
 464
 465         fputs(set, file);
 466         fwrite(line, len, 1, file);
 467         fputs(reset, file);
 468         if (has_trailing_carriage_return)
 469                 fputc('\r', file);
 470         if (has_trailing_newline)
 471                 fputc('\n', file);
 472 }
 473
 474 static void emit_add_line(const char *reset, struct emit_callback *ecbdata, const char *line, int len)
 475 {
 476         const char *ws = diff_get_color(ecbdata->color_diff, DIFF_WHITESPACE);
 477         const char *set = diff_get_color(ecbdata->color_diff, DIFF_FILE_NEW);
 478
 479         if (!*ws)
 480                 emit_line(ecbdata->file, set, reset, line, len);
 481         else {
 482                 /* Emit just the prefix, then the rest. */
 483                 emit_line(ecbdata->file, set, reset, line, ecbdata->nparents);
 484                 ws_check_emit(line + ecbdata->nparents,
 485                               len - ecbdata->nparents, ecbdata->ws_rule,
 486                               ecbdata->file, set, reset, ws);
 487         }
 488 }
 489
 490 static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
 491 {
 492         const char *cp;
 493         unsigned long allot;
 494         size_t l = len;
 495
 496         if (ecb->truncate)
 497                 return ecb->truncate(line, len);
 498         cp = line;
 499         allot = l;
 500         while (0 < l) {
 501                 (void) utf8_width(&cp, &l);
 502                 if (!cp)
 503                         break; /* truncated in the middle? */
 504         }
 505         return allot - l;
 506 }
 507
 508 static void fn_out_consume(void *priv, char *line, unsigned long len)
 509 {
 510         int i;
 511         int color;
 512         struct emit_callback *ecbdata = priv;
 513         const char *meta = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
 514         const char *plain = diff_get_color(ecbdata->color_diff, DIFF_PLAIN);
 515         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
 516
 517         *(ecbdata->found_changesp) = 1;
 518
 519         if (ecbdata->label_path[0]) {
 520                 const char *name_a_tab, *name_b_tab;
 521
 522                 name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
 523                 name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
 524
 525                 fprintf(ecbdata->file, "%s--- %s%s%s\n",
 526                         meta, ecbdata->label_path[0], reset, name_a_tab);
 527                 fprintf(ecbdata->file, "%s+++ %s%s%s\n",
 528                         meta, ecbdata->label_path[1], reset, name_b_tab);
 529                 ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
 530         }
 531
 532         if (diff_suppress_blank_empty
 533             && len == 2 && line[0] == ' ' && line[1] == '\n') {
 534                 line[0] = '\n';
 535                 len = 1;
 536         }
 537
 538         /* This is not really necessary for now because
 539          * this codepath only deals with two-way diffs.
 540          */
 541         for (i = 0; i < len && line[i] == '@'; i++)
 542                 ;
 543         if (2 <= i && i < len && line[i] == ' ') {
 544                 ecbdata->nparents = i - 1;
 545                 len = sane_truncate_line(ecbdata, line, len);
 546                 emit_line(ecbdata->file,
 547                           diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO),
 548                           reset, line, len);
 549                 if (line[len-1] != '\n')
 550                         putc('\n', ecbdata->file);
 551                 return;
 552         }
 553
 554         if (len < ecbdata->nparents) {
 555                 emit_line(ecbdata->file, reset, reset, line, len);
 556                 return;
 557         }
 558
 559         color = DIFF_PLAIN;
 560         if (ecbdata->diff_words && ecbdata->nparents != 1)
 561                 /* fall back to normal diff */
 562                 free_diff_words_data(ecbdata);
 563         if (ecbdata->diff_words) {
 564                 if (line[0] == '-') {
 565                         diff_words_append(line, len,
 566                                           &ecbdata->diff_words->minus);
 567                         return;
 568                 } else if (line[0] == '+') {
 569                         diff_words_append(line, len,
 570                                           &ecbdata->diff_words->plus);
 571                         return;
 572                 }
 573                 if (ecbdata->diff_words->minus.text.size ||
 574                     ecbdata->diff_words->plus.text.size)
 575                         diff_words_show(ecbdata->diff_words);
 576                 line++;
 577                 len--;
 578                 emit_line(ecbdata->file, plain, reset, line, len);
 579                 return;
 580         }
 581         for (i = 0; i < ecbdata->nparents && len; i++) {
 582                 if (line[i] == '-')
 583                         color = DIFF_FILE_OLD;
 584                 else if (line[i] == '+')
 585                         color = DIFF_FILE_NEW;
 586         }
 587
 588         if (color != DIFF_FILE_NEW) {
 589                 emit_line(ecbdata->file,
 590                           diff_get_color(ecbdata->color_diff, color),
 591                           reset, line, len);
 592                 return;
 593         }
 594         emit_add_line(reset, ecbdata, line, len);
 595 }
 596
 597 static char *pprint_rename(const char *a, const char *b)
 598 {
 599         const char *old = a;
 600         const char *new = b;
 601         struct strbuf name = STRBUF_INIT;
 602         int pfx_length, sfx_length;
 603         int len_a = strlen(a);
 604         int len_b = strlen(b);
 605         int a_midlen, b_midlen;
 606         int qlen_a = quote_c_style(a, NULL, NULL, 0);
 607         int qlen_b = quote_c_style(b, NULL, NULL, 0);
 608
 609         if (qlen_a || qlen_b) {
 610                 quote_c_style(a, &name, NULL, 0);
 611                 strbuf_addstr(&name, " => ");
 612                 quote_c_style(b, &name, NULL, 0);
 613                 return strbuf_detach(&name, NULL);
 614         }
 615
 616         /* Find common prefix */
 617         pfx_length = 0;
 618         while (*old && *new && *old == *new) {
 619                 if (*old == '/')
 620                         pfx_length = old - a + 1;
 621                 old++;
 622                 new++;
 623         }
 624
 625         /* Find common suffix */
 626         old = a + len_a;
 627         new = b + len_b;
 628         sfx_length = 0;
 629         while (a <= old && b <= new && *old == *new) {
 630                 if (*old == '/')
 631                         sfx_length = len_a - (old - a);
 632                 old--;
 633                 new--;
 634         }
 635
 636         /*
 637          * pfx{mid-a => mid-b}sfx
 638          * {pfx-a => pfx-b}sfx
 639          * pfx{sfx-a => sfx-b}
 640          * name-a => name-b
 641          */
 642         a_midlen = len_a - pfx_length - sfx_length;
 643         b_midlen = len_b - pfx_length - sfx_length;
 644         if (a_midlen < 0)
 645                 a_midlen = 0;
 646         if (b_midlen < 0)
 647                 b_midlen = 0;
 648
 649         strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
 650         if (pfx_length + sfx_length) {
 651                 strbuf_add(&name, a, pfx_length);
 652                 strbuf_addch(&name, '{');
 653         }
 654         strbuf_add(&name, a + pfx_length, a_midlen);
 655         strbuf_addstr(&name, " => ");
 656         strbuf_add(&name, b + pfx_length, b_midlen);
 657         if (pfx_length + sfx_length) {
 658                 strbuf_addch(&name, '}');
 659                 strbuf_add(&name, a + len_a - sfx_length, sfx_length);
 660         }
 661         return strbuf_detach(&name, NULL);
 662 }
 663
 664 struct diffstat_t {
 665         int nr;
 666         int alloc;
 667         struct diffstat_file {
 668                 char *from_name;
 669                 char *name;
 670                 char *print_name;
 671                 unsigned is_unmerged:1;
 672                 unsigned is_binary:1;
 673                 unsigned is_renamed:1;
 674                 unsigned int added, deleted;
 675         } **files;
 676 };
 677
 678 static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
 679                                           const char *name_a,
 680                                           const char *name_b)
 681 {
 682         struct diffstat_file *x;
 683         x = xcalloc(sizeof (*x), 1);
 684         if (diffstat->nr == diffstat->alloc) {
 685                 diffstat->alloc = alloc_nr(diffstat->alloc);
 686                 diffstat->files = xrealloc(diffstat->files,
 687                                 diffstat->alloc * sizeof(x));
 688         }
 689         diffstat->files[diffstat->nr++] = x;
 690         if (name_b) {
 691                 x->from_name = xstrdup(name_a);
 692                 x->name = xstrdup(name_b);
 693                 x->is_renamed = 1;
 694         }
 695         else {
 696                 x->from_name = NULL;
 697                 x->name = xstrdup(name_a);
 698         }
 699         return x;
 700 }
 701
 702 static void diffstat_consume(void *priv, char *line, unsigned long len)
 703 {
 704         struct diffstat_t *diffstat = priv;
 705         struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
 706
 707         if (line[0] == '+')
 708                 x->added++;
 709         else if (line[0] == '-')
 710                 x->deleted++;
 711 }
 712
 713 const char mime_boundary_leader[] = "------------";
 714
 715 static int scale_linear(int it, int width, int max_change)
 716 {
 717         /*
 718          * make sure that at least one '-' is printed if there were deletions,
 719          * and likewise for '+'.
 720          */
 721         if (max_change < 2)
 722                 return it;
 723         return ((it - 1) * (width - 1) + max_change - 1) / (max_change - 1);
 724 }
 725
 726 static void show_name(FILE *file,
 727                       const char *prefix, const char *name, int len,
 728                       const char *reset, const char *set)
 729 {
 730         fprintf(file, " %s%s%-*s%s |", set, prefix, len, name, reset);
 731 }
 732
 733 static void show_graph(FILE *file, char ch, int cnt, const char *set, const char *reset)
 734 {
 735         if (cnt <= 0)
 736                 return;
 737         fprintf(file, "%s", set);
 738         while (cnt--)
 739                 putc(ch, file);
 740         fprintf(file, "%s", reset);
 741 }
 742
 743 static void fill_print_name(struct diffstat_file *file)
 744 {
 745         char *pname;
 746
 747         if (file->print_name)
 748                 return;
 749
 750         if (!file->is_renamed) {
 751                 struct strbuf buf = STRBUF_INIT;
 752                 if (quote_c_style(file->name, &buf, NULL, 0)) {
 753                         pname = strbuf_detach(&buf, NULL);
 754                 } else {
 755                         pname = file->name;
 756                         strbuf_release(&buf);
 757                 }
 758         } else {
 759                 pname = pprint_rename(file->from_name, file->name);
 760         }
 761         file->print_name = pname;
 762 }
 763
 764 static void show_stats(struct diffstat_t* data, struct diff_options *options)
 765 {
 766         int i, len, add, del, total, adds = 0, dels = 0;
 767         int max_change = 0, max_len = 0;
 768         int total_files = data->nr;
 769         int width, name_width;
 770         const char *reset, *set, *add_c, *del_c;
 771
 772         if (data->nr == 0)
 773                 return;
 774
 775         width = options->stat_width ? options->stat_width : 80;
 776         name_width = options->stat_name_width ? options->stat_name_width : 50;
 777
 778         /* Sanity: give at least 5 columns to the graph,
 779          * but leave at least 10 columns for the name.
 780          */
 781         if (width < 25)
 782                 width = 25;
 783         if (name_width < 10)
 784                 name_width = 10;
 785         else if (width < name_width + 15)
 786                 name_width = width - 15;
 787
 788         /* Find the longest filename and max number of changes */
 789         reset = diff_get_color_opt(options, DIFF_RESET);
 790         set   = diff_get_color_opt(options, DIFF_PLAIN);
 791         add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
 792         del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
 793
 794         for (i = 0; i < data->nr; i++) {
 795                 struct diffstat_file *file = data->files[i];
 796                 int change = file->added + file->deleted;
 797                 fill_print_name(file);
 798                 len = strlen(file->print_name);
 799                 if (max_len < len)
 800                         max_len = len;
 801
 802                 if (file->is_binary || file->is_unmerged)
 803                         continue;
 804                 if (max_change < change)
 805                         max_change = change;
 806         }
 807
 808         /* Compute the width of the graph part;
 809          * 10 is for one blank at the beginning of the line plus
 810          * " | count " between the name and the graph.
 811          *
 812          * From here on, name_width is the width of the name area,
 813          * and width is the width of the graph area.
 814          */
 815         name_width = (name_width < max_len) ? name_width : max_len;
 816         if (width < (name_width + 10) + max_change)
 817                 width = width - (name_width + 10);
 818         else
 819                 width = max_change;
 820
 821         for (i = 0; i < data->nr; i++) {
 822                 const char *prefix = "";
 823                 char *name = data->files[i]->print_name;
 824                 int added = data->files[i]->added;
 825                 int deleted = data->files[i]->deleted;
 826                 int name_len;
 827
 828                 /*
 829                  * "scale" the filename
 830                  */
 831                 len = name_width;
 832                 name_len = strlen(name);
 833                 if (name_width < name_len) {
 834                         char *slash;
 835                         prefix = "...";
 836                         len -= 3;
 837                         name += name_len - len;
 838                         slash = strchr(name, '/');
 839                         if (slash)
 840                                 name = slash;
 841                 }
 842
 843                 if (data->files[i]->is_binary) {
 844                         show_name(options->file, prefix, name, len, reset, set);
 845                         fprintf(options->file, "  Bin ");
 846                         fprintf(options->file, "%s%d%s", del_c, deleted, reset);
 847                         fprintf(options->file, " -> ");
 848                         fprintf(options->file, "%s%d%s", add_c, added, reset);
 849                         fprintf(options->file, " bytes");
 850                         fprintf(options->file, "\n");
 851                         continue;
 852                 }
 853                 else if (data->files[i]->is_unmerged) {
 854                         show_name(options->file, prefix, name, len, reset, set);
 855                         fprintf(options->file, "  Unmerged\n");
 856                         continue;
 857                 }
 858                 else if (!data->files[i]->is_renamed &&
 859                          (added + deleted == 0)) {
 860                         total_files--;
 861                         continue;
 862                 }
 863
 864                 /*
 865                  * scale the add/delete
 866                  */
 867                 add = added;
 868                 del = deleted;
 869                 total = add + del;
 870                 adds += add;
 871                 dels += del;
 872
 873                 if (width <= max_change) {
 874                         add = scale_linear(add, width, max_change);
 875                         del = scale_linear(del, width, max_change);
 876                         total = add + del;
 877                 }
 878                 show_name(options->file, prefix, name, len, reset, set);
 879                 fprintf(options->file, "%5d%s", added + deleted,
 880                                 added + deleted ? " " : "");
 881                 show_graph(options->file, '+', add, add_c, reset);
 882                 show_graph(options->file, '-', del, del_c, reset);
 883                 fprintf(options->file, "\n");
 884         }
 885         fprintf(options->file,
 886                "%s %d files changed, %d insertions(+), %d deletions(-)%s\n",
 887                set, total_files, adds, dels, reset);
 888 }
 889
 890 static void show_shortstats(struct diffstat_t* data, struct diff_options *options)
 891 {
 892         int i, adds = 0, dels = 0, total_files = data->nr;
 893
 894         if (data->nr == 0)
 895                 return;
 896
 897         for (i = 0; i < data->nr; i++) {
 898                 if (!data->files[i]->is_binary &&
 899                     !data->files[i]->is_unmerged) {
 900                         int added = data->files[i]->added;
 901                         int deleted= data->files[i]->deleted;
 902                         if (!data->files[i]->is_renamed &&
 903                             (added + deleted == 0)) {
 904                                 total_files--;
 905                         } else {
 906                                 adds += added;
 907                                 dels += deleted;
 908                         }
 909                 }
 910         }
 911         fprintf(options->file, " %d files changed, %d insertions(+), %d deletions(-)\n",
 912                total_files, adds, dels);
 913 }
 914
 915 static void show_numstat(struct diffstat_t* data, struct diff_options *options)
 916 {
 917         int i;
 918
 919         if (data->nr == 0)
 920                 return;
 921
 922         for (i = 0; i < data->nr; i++) {
 923                 struct diffstat_file *file = data->files[i];
 924
 925                 if (file->is_binary)
 926                         fprintf(options->file, "-\t-\t");
 927                 else
 928                         fprintf(options->file,
 929                                 "%d\t%d\t", file->added, file->deleted);
 930                 if (options->line_termination) {
 931                         fill_print_name(file);
 932                         if (!file->is_renamed)
 933                                 write_name_quoted(file->name, options->file,
 934                                                   options->line_termination);
 935                         else {
 936                                 fputs(file->print_name, options->file);
 937                                 putc(options->line_termination, options->file);
 938                         }
 939                 } else {
 940                         if (file->is_renamed) {
 941                                 putc('\0', options->file);
 942                                 write_name_quoted(file->from_name, options->file, '\0');
 943                         }
 944                         write_name_quoted(file->name, options->file, '\0');
 945                 }
 946         }
 947 }
 948
 949 struct dirstat_file {
 950         const char *name;
 951         unsigned long changed;
 952 };
 953
 954 struct dirstat_dir {
 955         struct dirstat_file *files;
 956         int alloc, nr, percent, cumulative;
 957 };
 958
 959 static long gather_dirstat(FILE *file, struct dirstat_dir *dir, unsigned long changed, const char *base, int baselen)
 960 {
 961         unsigned long this_dir = 0;
 962         unsigned int sources = 0;
 963
 964         while (dir->nr) {
 965                 struct dirstat_file *f = dir->files;
 966                 int namelen = strlen(f->name);
 967                 unsigned long this;
 968                 char *slash;
 969
 970                 if (namelen < baselen)
 971                         break;
 972                 if (memcmp(f->name, base, baselen))
 973                         break;
 974                 slash = strchr(f->name + baselen, '/');
 975                 if (slash) {
 976                         int newbaselen = slash + 1 - f->name;
 977                         this = gather_dirstat(file, dir, changed, f->name, newbaselen);
 978                         sources++;
 979                 } else {
 980                         this = f->changed;
 981                         dir->files++;
 982                         dir->nr--;
 983                         sources += 2;
 984                 }
 985                 this_dir += this;
 986         }
 987
 988         /*
 989          * We don't report dirstat's for
 990          *  - the top level
 991          *  - or cases where everything came from a single directory
 992          *    under this directory (sources == 1).
 993          */
 994         if (baselen && sources != 1) {
 995                 int permille = this_dir * 1000 / changed;
 996                 if (permille) {
 997                         int percent = permille / 10;
 998                         if (percent >= dir->percent) {
 999                                 fprintf(file, "%4d.%01d%% %.*s\n", percent, permille % 10, baselen, base);
1000                                 if (!dir->cumulative)
1001                                         return 0;
1002                         }
1003                 }
1004         }
1005         return this_dir;
1006 }
1007
1008 static int dirstat_compare(const void *_a, const void *_b)
1009 {
1010         const struct dirstat_file *a = _a;
1011         const struct dirstat_file *b = _b;
1012         return strcmp(a->name, b->name);
1013 }
1014
1015 static void show_dirstat(struct diff_options *options)
1016 {
1017         int i;
1018         unsigned long changed;
1019         struct dirstat_dir dir;
1020         struct diff_queue_struct *q = &diff_queued_diff;
1021
1022         dir.files = NULL;
1023         dir.alloc = 0;
1024         dir.nr = 0;
1025         dir.percent = options->dirstat_percent;
1026         dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
1027
1028         changed = 0;
1029         for (i = 0; i < q->nr; i++) {
1030                 struct diff_filepair *p = q->queue[i];
1031                 const char *name;
1032                 unsigned long copied, added, damage;
1033
1034                 name = p->one->path ? p->one->path : p->two->path;
1035
1036                 if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
1037                         diff_populate_filespec(p->one, 0);
1038                         diff_populate_filespec(p->two, 0);
1039                         diffcore_count_changes(p->one, p->two, NULL, NULL, 0,
1040                                                &copied, &added);
1041                         diff_free_filespec_data(p->one);
1042                         diff_free_filespec_data(p->two);
1043                 } else if (DIFF_FILE_VALID(p->one)) {
1044                         diff_populate_filespec(p->one, 1);
1045                         copied = added = 0;
1046                         diff_free_filespec_data(p->one);
1047                 } else if (DIFF_FILE_VALID(p->two)) {
1048                         diff_populate_filespec(p->two, 1);
1049                         copied = 0;
1050                         added = p->two->size;
1051                         diff_free_filespec_data(p->two);
1052                 } else
1053                         continue;
1054
1055                 /*
1056                  * Original minus copied is the removed material,
1057                  * added is the new material.  They are both damages
1058                  * made to the preimage. In --dirstat-by-file mode, count
1059                  * damaged files, not damaged lines. This is done by
1060                  * counting only a single damaged line per file.
1061                  */
1062                 damage = (p->one->size - copied) + added;
1063                 if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE) && damage > 0)
1064                         damage = 1;
1065
1066                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1067                 dir.files[dir.nr].name = name;
1068                 dir.files[dir.nr].changed = damage;
1069                 changed += damage;
1070                 dir.nr++;
1071         }
1072
1073         /* This can happen even with many files, if everything was renames */
1074         if (!changed)
1075                 return;
1076
1077         /* Show all directories with more than x% of the changes */
1078         qsort(dir.files, dir.nr, sizeof(dir.files[0]), dirstat_compare);
1079         gather_dirstat(options->file, &dir, changed, "", 0);
1080 }
1081
1082 static void free_diffstat_info(struct diffstat_t *diffstat)
1083 {
1084         int i;
1085         for (i = 0; i < diffstat->nr; i++) {
1086                 struct diffstat_file *f = diffstat->files[i];
1087                 if (f->name != f->print_name)
1088                         free(f->print_name);
1089                 free(f->name);
1090                 free(f->from_name);
1091                 free(f);
1092         }
1093         free(diffstat->files);
1094 }
1095
1096 struct checkdiff_t {
1097         const char *filename;
1098         int lineno;
1099         struct diff_options *o;
1100         unsigned ws_rule;
1101         unsigned status;
1102         int trailing_blanks_start;
1103 };
1104
1105 static int is_conflict_marker(const char *line, unsigned long len)
1106 {
1107         char firstchar;
1108         int cnt;
1109
1110         if (len < 8)
1111                 return 0;
1112         firstchar = line[0];
1113         switch (firstchar) {
1114         case '=': case '>': case '<':
1115                 break;
1116         default:
1117                 return 0;
1118         }
1119         for (cnt = 1; cnt < 7; cnt++)
1120                 if (line[cnt] != firstchar)
1121                         return 0;
1122         /* line[0] thru line[6] are same as firstchar */
1123         if (firstchar == '=') {
1124                 /* divider between ours and theirs? */
1125                 if (len != 8 || line[7] != '\n')
1126                         return 0;
1127         } else if (len < 8 || !isspace(line[7])) {
1128                 /* not divider before ours nor after theirs */
1129                 return 0;
1130         }
1131         return 1;
1132 }
1133
1134 static void checkdiff_consume(void *priv, char *line, unsigned long len)
1135 {
1136         struct checkdiff_t *data = priv;
1137         int color_diff = DIFF_OPT_TST(data->o, COLOR_DIFF);
1138         const char *ws = diff_get_color(color_diff, DIFF_WHITESPACE);
1139         const char *reset = diff_get_color(color_diff, DIFF_RESET);
1140         const char *set = diff_get_color(color_diff, DIFF_FILE_NEW);
1141         char *err;
1142
1143         if (line[0] == '+') {
1144                 unsigned bad;
1145                 data->lineno++;
1146                 if (!ws_blank_line(line + 1, len - 1, data->ws_rule))
1147                         data->trailing_blanks_start = 0;
1148                 else if (!data->trailing_blanks_start)
1149                         data->trailing_blanks_start = data->lineno;
1150                 if (is_conflict_marker(line + 1, len - 1)) {
1151                         data->status |= 1;
1152                         fprintf(data->o->file,
1153                                 "%s:%d: leftover conflict marker\n",
1154                                 data->filename, data->lineno);
1155                 }
1156                 bad = ws_check(line + 1, len - 1, data->ws_rule);
1157                 if (!bad)
1158                         return;
1159                 data->status |= bad;
1160                 err = whitespace_error_string(bad);
1161                 fprintf(data->o->file, "%s:%d: %s.\n",
1162                         data->filename, data->lineno, err);
1163                 free(err);
1164                 emit_line(data->o->file, set, reset, line, 1);
1165                 ws_check_emit(line + 1, len - 1, data->ws_rule,
1166                               data->o->file, set, reset, ws);
1167         } else if (line[0] == ' ') {
1168                 data->lineno++;
1169                 data->trailing_blanks_start = 0;
1170         } else if (line[0] == '@') {
1171                 char *plus = strchr(line, '+');
1172                 if (plus)
1173                         data->lineno = strtol(plus, NULL, 10) - 1;
1174                 else
1175                         die("invalid diff");
1176                 data->trailing_blanks_start = 0;
1177         }
1178 }
1179
1180 static unsigned char *deflate_it(char *data,
1181                                  unsigned long size,
1182                                  unsigned long *result_size)
1183 {
1184         int bound;
1185         unsigned char *deflated;
1186         z_stream stream;
1187
1188         memset(&stream, 0, sizeof(stream));
1189         deflateInit(&stream, zlib_compression_level);
1190         bound = deflateBound(&stream, size);
1191         deflated = xmalloc(bound);
1192         stream.next_out = deflated;
1193         stream.avail_out = bound;
1194
1195         stream.next_in = (unsigned char *)data;
1196         stream.avail_in = size;
1197         while (deflate(&stream, Z_FINISH) == Z_OK)
1198                 ; /* nothing */
1199         deflateEnd(&stream);
1200         *result_size = stream.total_out;
1201         return deflated;
1202 }
1203
1204 static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two)
1205 {
1206         void *cp;
1207         void *delta;
1208         void *deflated;
1209         void *data;
1210         unsigned long orig_size;
1211         unsigned long delta_size;
1212         unsigned long deflate_size;
1213         unsigned long data_size;
1214
1215         /* We could do deflated delta, or we could do just deflated two,
1216          * whichever is smaller.
1217          */
1218         delta = NULL;
1219         deflated = deflate_it(two->ptr, two->size, &deflate_size);
1220         if (one->size && two->size) {
1221                 delta = diff_delta(one->ptr, one->size,
1222                                    two->ptr, two->size,
1223                                    &delta_size, deflate_size);
1224                 if (delta) {
1225                         void *to_free = delta;
1226                         orig_size = delta_size;
1227                         delta = deflate_it(delta, delta_size, &delta_size);
1228                         free(to_free);
1229                 }
1230         }
1231
1232         if (delta && delta_size < deflate_size) {
1233                 fprintf(file, "delta %lu\n", orig_size);
1234                 free(deflated);
1235                 data = delta;
1236                 data_size = delta_size;
1237         }
1238         else {
1239                 fprintf(file, "literal %lu\n", two->size);
1240                 free(delta);
1241                 data = deflated;
1242                 data_size = deflate_size;
1243         }
1244
1245         /* emit data encoded in base85 */
1246         cp = data;
1247         while (data_size) {
1248                 int bytes = (52 < data_size) ? 52 : data_size;
1249                 char line[70];
1250                 data_size -= bytes;
1251                 if (bytes <= 26)
1252                         line[0] = bytes + 'A' - 1;
1253                 else
1254                         line[0] = bytes - 26 + 'a' - 1;
1255                 encode_85(line + 1, cp, bytes);
1256                 cp = (char *) cp + bytes;
1257                 fputs(line, file);
1258                 fputc('\n', file);
1259         }
1260         fprintf(file, "\n");
1261         free(data);
1262 }
1263
1264 static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two)
1265 {
1266         fprintf(file, "GIT binary patch\n");
1267         emit_binary_diff_body(file, one, two);
1268         emit_binary_diff_body(file, two, one);
1269 }
1270
1271 static void diff_filespec_check_attr(struct diff_filespec *one)
1272 {
1273         struct userdiff_driver *drv;
1274         int check_from_data = 0;
1275
1276         if (one->checked_attr)
1277                 return;
1278
1279         drv = userdiff_find_by_path(one->path);
1280         one->is_binary = 0;
1281
1282         /* binaryness */
1283         if (drv == USERDIFF_ATTR_TRUE)
1284                 ;
1285         else if (drv == USERDIFF_ATTR_FALSE)
1286                 one->is_binary = 1;
1287         else
1288                 check_from_data = 1;
1289
1290         if (check_from_data) {
1291                 if (!one->data && DIFF_FILE_VALID(one))
1292                         diff_populate_filespec(one, 0);
1293
1294                 if (one->data)
1295                         one->is_binary = buffer_is_binary(one->data, one->size);
1296         }
1297 }
1298
1299 int diff_filespec_is_binary(struct diff_filespec *one)
1300 {
1301         diff_filespec_check_attr(one);
1302         return one->is_binary;
1303 }
1304
1305 static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
1306 {
1307         struct userdiff_driver *drv = userdiff_find_by_path(one->path);
1308         if (!drv)
1309                 drv = userdiff_find_by_name("default");
1310         return drv && drv->funcname.pattern ? &drv->funcname : NULL;
1311 }
1312
1313 void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
1314 {
1315         if (!options->a_prefix)
1316                 options->a_prefix = a;
1317         if (!options->b_prefix)
1318                 options->b_prefix = b;
1319 }
1320
1321 static void builtin_diff(const char *name_a,
1322                          const char *name_b,
1323                          struct diff_filespec *one,
1324                          struct diff_filespec *two,
1325                          const char *xfrm_msg,
1326                          struct diff_options *o,
1327                          int complete_rewrite)
1328 {
1329         mmfile_t mf1, mf2;
1330         const char *lbl[2];
1331         char *a_one, *b_two;
1332         const char *set = diff_get_color_opt(o, DIFF_METAINFO);
1333         const char *reset = diff_get_color_opt(o, DIFF_RESET);
1334         const char *a_prefix, *b_prefix;
1335
1336         diff_set_mnemonic_prefix(o, "a/", "b/");
1337         if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
1338                 a_prefix = o->b_prefix;
1339                 b_prefix = o->a_prefix;
1340         } else {
1341                 a_prefix = o->a_prefix;
1342                 b_prefix = o->b_prefix;
1343         }
1344
1345         /* Never use a non-valid filename anywhere if at all possible */
1346         name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
1347         name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
1348
1349         a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
1350         b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
1351         lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
1352         lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
1353         fprintf(o->file, "%sdiff --git %s %s%s\n", set, a_one, b_two, reset);
1354         if (lbl[0][0] == '/') {
1355                 /* /dev/null */
1356                 fprintf(o->file, "%snew file mode %06o%s\n", set, two->mode, reset);
1357                 if (xfrm_msg && xfrm_msg[0])
1358                         fprintf(o->file, "%s%s%s\n", set, xfrm_msg, reset);
1359         }
1360         else if (lbl[1][0] == '/') {
1361                 fprintf(o->file, "%sdeleted file mode %06o%s\n", set, one->mode, reset);
1362                 if (xfrm_msg && xfrm_msg[0])
1363                         fprintf(o->file, "%s%s%s\n", set, xfrm_msg, reset);
1364         }
1365         else {
1366                 if (one->mode != two->mode) {
1367                         fprintf(o->file, "%sold mode %06o%s\n", set, one->mode, reset);
1368                         fprintf(o->file, "%snew mode %06o%s\n", set, two->mode, reset);
1369                 }
1370                 if (xfrm_msg && xfrm_msg[0])
1371                         fprintf(o->file, "%s%s%s\n", set, xfrm_msg, reset);
1372                 /*
1373                  * we do not run diff between different kind
1374                  * of objects.
1375                  */
1376                 if ((one->mode ^ two->mode) & S_IFMT)
1377                         goto free_ab_and_return;
1378                 if (complete_rewrite) {
1379                         emit_rewrite_diff(name_a, name_b, one, two, o);
1380                         o->found_changes = 1;
1381                         goto free_ab_and_return;
1382                 }
1383         }
1384
1385         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
1386                 die("unable to read files to diff");
1387
1388         if (!DIFF_OPT_TST(o, TEXT) &&
1389             (diff_filespec_is_binary(one) || diff_filespec_is_binary(two))) {
1390                 /* Quite common confusing case */
1391                 if (mf1.size == mf2.size &&
1392                     !memcmp(mf1.ptr, mf2.ptr, mf1.size))
1393                         goto free_ab_and_return;
1394                 if (DIFF_OPT_TST(o, BINARY))
1395                         emit_binary_diff(o->file, &mf1, &mf2);
1396                 else
1397                         fprintf(o->file, "Binary files %s and %s differ\n",
1398                                 lbl[0], lbl[1]);
1399                 o->found_changes = 1;
1400         }
1401         else {
1402                 /* Crazy xdl interfaces.. */
1403                 const char *diffopts = getenv("GIT_DIFF_OPTS");
1404                 xpparam_t xpp;
1405                 xdemitconf_t xecfg;
1406                 xdemitcb_t ecb;
1407                 struct emit_callback ecbdata;
1408                 const struct userdiff_funcname *pe;
1409
1410                 pe = diff_funcname_pattern(one);
1411                 if (!pe)
1412                         pe = diff_funcname_pattern(two);
1413
1414                 memset(&xecfg, 0, sizeof(xecfg));
1415                 memset(&ecbdata, 0, sizeof(ecbdata));
1416                 ecbdata.label_path = lbl;
1417                 ecbdata.color_diff = DIFF_OPT_TST(o, COLOR_DIFF);
1418                 ecbdata.found_changesp = &o->found_changes;
1419                 ecbdata.ws_rule = whitespace_rule(name_b ? name_b : name_a);
1420                 ecbdata.file = o->file;
1421                 xpp.flags = XDF_NEED_MINIMAL | o->xdl_opts;
1422                 xecfg.ctxlen = o->context;
1423                 xecfg.flags = XDL_EMIT_FUNCNAMES;
1424                 if (pe)
1425                         xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
1426                 if (!diffopts)
1427                         ;
1428                 else if (!prefixcmp(diffopts, "--unified="))
1429                         xecfg.ctxlen = strtoul(diffopts + 10, NULL, 10);
1430                 else if (!prefixcmp(diffopts, "-u"))
1431                         xecfg.ctxlen = strtoul(diffopts + 2, NULL, 10);
1432                 if (DIFF_OPT_TST(o, COLOR_DIFF_WORDS)) {
1433                         ecbdata.diff_words =
1434                                 xcalloc(1, sizeof(struct diff_words_data));
1435                         ecbdata.diff_words->file = o->file;
1436                 }
1437                 xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
1438                               &xpp, &xecfg, &ecb);
1439                 if (DIFF_OPT_TST(o, COLOR_DIFF_WORDS))
1440                         free_diff_words_data(&ecbdata);
1441         }
1442
1443  free_ab_and_return:
1444         diff_free_filespec_data(one);
1445         diff_free_filespec_data(two);
1446         free(a_one);
1447         free(b_two);
1448         return;
1449 }
1450
1451 static void builtin_diffstat(const char *name_a, const char *name_b,
1452                              struct diff_filespec *one,
1453                              struct diff_filespec *two,
1454                              struct diffstat_t *diffstat,
1455                              struct diff_options *o,
1456                              int complete_rewrite)
1457 {
1458         mmfile_t mf1, mf2;
1459         struct diffstat_file *data;
1460
1461         data = diffstat_add(diffstat, name_a, name_b);
1462
1463         if (!one || !two) {
1464                 data->is_unmerged = 1;
1465                 return;
1466         }
1467         if (complete_rewrite) {
1468                 diff_populate_filespec(one, 0);
1469                 diff_populate_filespec(two, 0);
1470                 data->deleted = count_lines(one->data, one->size);
1471                 data->added = count_lines(two->data, two->size);
1472                 goto free_and_return;
1473         }
1474         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
1475                 die("unable to read files to diff");
1476
1477         if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
1478                 data->is_binary = 1;
1479                 data->added = mf2.size;
1480                 data->deleted = mf1.size;
1481         } else {
1482                 /* Crazy xdl interfaces.. */
1483                 xpparam_t xpp;
1484                 xdemitconf_t xecfg;
1485                 xdemitcb_t ecb;
1486
1487                 memset(&xecfg, 0, sizeof(xecfg));
1488                 xpp.flags = XDF_NEED_MINIMAL | o->xdl_opts;
1489                 xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
1490                               &xpp, &xecfg, &ecb);
1491         }
1492
1493  free_and_return:
1494         diff_free_filespec_data(one);
1495         diff_free_filespec_data(two);
1496 }
1497
1498 static void builtin_checkdiff(const char *name_a, const char *name_b,
1499                               const char *attr_path,
1500                               struct diff_filespec *one,
1501                               struct diff_filespec *two,
1502                               struct diff_options *o)
1503 {
1504         mmfile_t mf1, mf2;
1505         struct checkdiff_t data;
1506
1507         if (!two)
1508                 return;
1509
1510         memset(&data, 0, sizeof(data));
1511         data.filename = name_b ? name_b : name_a;
1512         data.lineno = 0;
1513         data.o = o;
1514         data.ws_rule = whitespace_rule(attr_path);
1515
1516         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
1517                 die("unable to read files to diff");
1518
1519         /*
1520          * All the other codepaths check both sides, but not checking
1521          * the "old" side here is deliberate.  We are checking the newly
1522          * introduced changes, and as long as the "new" side is text, we
1523          * can and should check what it introduces.
1524          */
1525         if (diff_filespec_is_binary(two))
1526                 goto free_and_return;
1527         else {
1528                 /* Crazy xdl interfaces.. */
1529                 xpparam_t xpp;
1530                 xdemitconf_t xecfg;
1531                 xdemitcb_t ecb;
1532
1533                 memset(&xecfg, 0, sizeof(xecfg));
1534                 xecfg.ctxlen = 1; /* at least one context line */
1535                 xpp.flags = XDF_NEED_MINIMAL;
1536                 xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
1537                               &xpp, &xecfg, &ecb);
1538
1539                 if ((data.ws_rule & WS_TRAILING_SPACE) &&
1540                     data.trailing_blanks_start) {
1541                         fprintf(o->file, "%s:%d: ends with blank lines.\n",
1542                                 data.filename, data.trailing_blanks_start);
1543                         data.status = 1; /* report errors */
1544                 }
1545         }
1546  free_and_return:
1547         diff_free_filespec_data(one);
1548         diff_free_filespec_data(two);
1549         if (data.status)
1550                 DIFF_OPT_SET(o, CHECK_FAILED);
1551 }
1552
1553 struct diff_filespec *alloc_filespec(const char *path)
1554 {
1555         int namelen = strlen(path);
1556         struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
1557
1558         memset(spec, 0, sizeof(*spec));
1559         spec->path = (char *)(spec + 1);
1560         memcpy(spec->path, path, namelen+1);
1561         spec->count = 1;
1562         return spec;
1563 }
1564
1565 void free_filespec(struct diff_filespec *spec)
1566 {
1567         if (!--spec->count) {
1568                 diff_free_filespec_data(spec);
1569                 free(spec);
1570         }
1571 }
1572
1573 void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
1574                    unsigned short mode)
1575 {
1576         if (mode) {
1577                 spec->mode = canon_mode(mode);
1578                 hashcpy(spec->sha1, sha1);
1579                 spec->sha1_valid = !is_null_sha1(sha1);
1580         }
1581 }
1582
1583 /*
1584  * Given a name and sha1 pair, if the index tells us the file in
1585  * the work tree has that object contents, return true, so that
1586  * prepare_temp_file() does not have to inflate and extract.
1587  */
1588 static int reuse_worktree_file(const char *name, const unsigned char *sha1, int want_file)
1589 {
1590         struct cache_entry *ce;
1591         struct stat st;
1592         int pos, len;
1593
1594         /* We do not read the cache ourselves here, because the
1595          * benchmark with my previous version that always reads cache
1596          * shows that it makes things worse for diff-tree comparing
1597          * two linux-2.6 kernel trees in an already checked out work
1598          * tree.  This is because most diff-tree comparisons deal with
1599          * only a small number of files, while reading the cache is
1600          * expensive for a large project, and its cost outweighs the
1601          * savings we get by not inflating the object to a temporary
1602          * file.  Practically, this code only helps when we are used
1603          * by diff-cache --cached, which does read the cache before
1604          * calling us.
1605          */
1606         if (!active_cache)
1607                 return 0;
1608
1609         /* We want to avoid the working directory if our caller
1610          * doesn't need the data in a normal file, this system
1611          * is rather slow with its stat/open/mmap/close syscalls,
1612          * and the object is contained in a pack file.  The pack
1613          * is probably already open and will be faster to obtain
1614          * the data through than the working directory.  Loose
1615          * objects however would tend to be slower as they need
1616          * to be individually opened and inflated.
1617          */
1618         if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(sha1, NULL))
1619                 return 0;
1620
1621         len = strlen(name);
1622         pos = cache_name_pos(name, len);
1623         if (pos < 0)
1624                 return 0;
1625         ce = active_cache[pos];
1626
1627         /*
1628          * This is not the sha1 we are looking for, or
1629          * unreusable because it is not a regular file.
1630          */
1631         if (hashcmp(sha1, ce->sha1) || !S_ISREG(ce->ce_mode))
1632                 return 0;
1633
1634         /*
1635          * If ce matches the file in the work tree, we can reuse it.
1636          */
1637         if (ce_uptodate(ce) ||
1638             (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
1639                 return 1;
1640
1641         return 0;
1642 }
1643
1644 static int populate_from_stdin(struct diff_filespec *s)
1645 {
1646         struct strbuf buf = STRBUF_INIT;
1647         size_t size = 0;
1648
1649         if (strbuf_read(&buf, 0, 0) < 0)
1650                 return error("error while reading from stdin %s",
1651                                      strerror(errno));
1652
1653         s->should_munmap = 0;
1654         s->data = strbuf_detach(&buf, &size);
1655         s->size = size;
1656         s->should_free = 1;
1657         return 0;
1658 }
1659
1660 static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
1661 {
1662         int len;
1663         char *data = xmalloc(100);
1664         len = snprintf(data, 100,
1665                 "Subproject commit %s\n", sha1_to_hex(s->sha1));
1666         s->data = data;
1667         s->size = len;
1668         s->should_free = 1;
1669         if (size_only) {
1670                 s->data = NULL;
1671                 free(data);
1672         }
1673         return 0;
1674 }
1675
1676 /*
1677  * While doing rename detection and pickaxe operation, we may need to
1678  * grab the data for the blob (or file) for our own in-core comparison.
1679  * diff_filespec has data and size fields for this purpose.
1680  */
1681 int diff_populate_filespec(struct diff_filespec *s, int size_only)
1682 {
1683         int err = 0;
1684         if (!DIFF_FILE_VALID(s))
1685                 die("internal error: asking to populate invalid file.");
1686         if (S_ISDIR(s->mode))
1687                 return -1;
1688
1689         if (s->data)
1690                 return 0;
1691
1692         if (size_only && 0 < s->size)
1693                 return 0;
1694
1695         if (S_ISGITLINK(s->mode))
1696                 return diff_populate_gitlink(s, size_only);
1697
1698         if (!s->sha1_valid ||
1699             reuse_worktree_file(s->path, s->sha1, 0)) {
1700                 struct strbuf buf = STRBUF_INIT;
1701                 struct stat st;
1702                 int fd;
1703
1704                 if (!strcmp(s->path, "-"))
1705                         return populate_from_stdin(s);
1706
1707                 if (lstat(s->path, &st) < 0) {
1708                         if (errno == ENOENT) {
1709                         err_empty:
1710                                 err = -1;
1711                         empty:
1712                                 s->data = (char *)"";
1713                                 s->size = 0;
1714                                 return err;
1715                         }
1716                 }
1717                 s->size = xsize_t(st.st_size);
1718                 if (!s->size)
1719                         goto empty;
1720                 if (size_only)
1721                         return 0;
1722                 if (S_ISLNK(st.st_mode)) {
1723                         int ret;
1724                         s->data = xmalloc(s->size);
1725                         s->should_free = 1;
1726                         ret = readlink(s->path, s->data, s->size);
1727                         if (ret < 0) {
1728                                 free(s->data);
1729                                 goto err_empty;
1730                         }
1731                         return 0;
1732                 }
1733                 fd = open(s->path, O_RDONLY);
1734                 if (fd < 0)
1735                         goto err_empty;
1736                 s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
1737                 close(fd);
1738                 s->should_munmap = 1;
1739
1740                 /*
1741                  * Convert from working tree format to canonical git format
1742                  */
1743                 if (convert_to_git(s->path, s->data, s->size, &buf, safe_crlf)) {
1744                         size_t size = 0;
1745                         munmap(s->data, s->size);
1746                         s->should_munmap = 0;
1747                         s->data = strbuf_detach(&buf, &size);
1748                         s->size = size;
1749                         s->should_free = 1;
1750                 }
1751         }
1752         else {
1753                 enum object_type type;
1754                 if (size_only)
1755                         type = sha1_object_info(s->sha1, &s->size);
1756                 else {
1757                         s->data = read_sha1_file(s->sha1, &type, &s->size);
1758                         s->should_free = 1;
1759                 }
1760         }
1761         return 0;
1762 }
1763
1764 void diff_free_filespec_blob(struct diff_filespec *s)
1765 {
1766         if (s->should_free)
1767                 free(s->data);
1768         else if (s->should_munmap)
1769                 munmap(s->data, s->size);
1770
1771         if (s->should_free || s->should_munmap) {
1772                 s->should_free = s->should_munmap = 0;
1773                 s->data = NULL;
1774         }
1775 }
1776
1777 void diff_free_filespec_data(struct diff_filespec *s)
1778 {
1779         diff_free_filespec_blob(s);
1780         free(s->cnt_data);
1781         s->cnt_data = NULL;
1782 }
1783
1784 static void prep_temp_blob(struct diff_tempfile *temp,
1785                            void *blob,
1786                            unsigned long size,
1787                            const unsigned char *sha1,
1788                            int mode)
1789 {
1790         int fd;
1791
1792         fd = git_mkstemp(temp->tmp_path, PATH_MAX, ".diff_XXXXXX");
1793         if (fd < 0)
1794                 die("unable to create temp-file: %s", strerror(errno));
1795         if (write_in_full(fd, blob, size) != size)
1796                 die("unable to write temp-file");
1797         close(fd);
1798         temp->name = temp->tmp_path;
1799         strcpy(temp->hex, sha1_to_hex(sha1));
1800         temp->hex[40] = 0;
1801         sprintf(temp->mode, "%06o", mode);
1802 }
1803
1804 static void prepare_temp_file(const char *name,
1805                               struct diff_tempfile *temp,
1806                               struct diff_filespec *one)
1807 {
1808         if (!DIFF_FILE_VALID(one)) {
1809         not_a_valid_file:
1810                 /* A '-' entry produces this for file-2, and
1811                  * a '+' entry produces this for file-1.
1812                  */
1813                 temp->name = "/dev/null";
1814                 strcpy(temp->hex, ".");
1815                 strcpy(temp->mode, ".");
1816                 return;
1817         }
1818
1819         if (!one->sha1_valid ||
1820             reuse_worktree_file(name, one->sha1, 1)) {
1821                 struct stat st;
1822                 if (lstat(name, &st) < 0) {
1823                         if (errno == ENOENT)
1824                                 goto not_a_valid_file;
1825                         die("stat(%s): %s", name, strerror(errno));
1826                 }
1827                 if (S_ISLNK(st.st_mode)) {
1828                         int ret;
1829                         char buf[PATH_MAX + 1]; /* ought to be SYMLINK_MAX */
1830                         size_t sz = xsize_t(st.st_size);
1831                         if (sizeof(buf) <= st.st_size)
1832                                 die("symlink too long: %s", name);
1833                         ret = readlink(name, buf, sz);
1834                         if (ret < 0)
1835                                 die("readlink(%s)", name);
1836                         prep_temp_blob(temp, buf, sz,
1837                                        (one->sha1_valid ?
1838                                         one->sha1 : null_sha1),
1839                                        (one->sha1_valid ?
1840                                         one->mode : S_IFLNK));
1841                 }
1842                 else {
1843                         /* we can borrow from the file in the work tree */
1844                         temp->name = name;
1845                         if (!one->sha1_valid)
1846                                 strcpy(temp->hex, sha1_to_hex(null_sha1));
1847                         else
1848                                 strcpy(temp->hex, sha1_to_hex(one->sha1));
1849                         /* Even though we may sometimes borrow the
1850                          * contents from the work tree, we always want
1851                          * one->mode.  mode is trustworthy even when
1852                          * !(one->sha1_valid), as long as
1853                          * DIFF_FILE_VALID(one).
1854                          */
1855                         sprintf(temp->mode, "%06o", one->mode);
1856                 }
1857                 return;
1858         }
1859         else {
1860                 if (diff_populate_filespec(one, 0))
1861                         die("cannot read data blob for %s", one->path);
1862                 prep_temp_blob(temp, one->data, one->size,
1863                                one->sha1, one->mode);
1864         }
1865 }
1866
1867 static void remove_tempfile(void)
1868 {
1869         int i;
1870
1871         for (i = 0; i < 2; i++)
1872                 if (diff_temp[i].name == diff_temp[i].tmp_path) {
1873                         unlink(diff_temp[i].name);
1874                         diff_temp[i].name = NULL;
1875                 }
1876 }
1877
1878 static void remove_tempfile_on_signal(int signo)
1879 {
1880         remove_tempfile();
1881         signal(SIGINT, SIG_DFL);
1882         raise(signo);
1883 }
1884
1885 /* An external diff command takes:
1886  *
1887  * diff-cmd name infile1 infile1-sha1 infile1-mode \
1888  *               infile2 infile2-sha1 infile2-mode [ rename-to ]
1889  *
1890  */
1891 static void run_external_diff(const char *pgm,
1892                               const char *name,
1893                               const char *other,
1894                               struct diff_filespec *one,
1895                               struct diff_filespec *two,
1896                               const char *xfrm_msg,
1897                               int complete_rewrite)
1898 {
1899         const char *spawn_arg[10];
1900         struct diff_tempfile *temp = diff_temp;
1901         int retval;
1902         static int atexit_asked = 0;
1903         const char *othername;
1904         const char **arg = &spawn_arg[0];
1905
1906         othername = (other? other : name);
1907         if (one && two) {
1908                 prepare_temp_file(name, &temp[0], one);
1909                 prepare_temp_file(othername, &temp[1], two);
1910                 if (! atexit_asked &&
1911                     (temp[0].name == temp[0].tmp_path ||
1912                      temp[1].name == temp[1].tmp_path)) {
1913                         atexit_asked = 1;
1914                         atexit(remove_tempfile);
1915                 }
1916                 signal(SIGINT, remove_tempfile_on_signal);
1917         }
1918
1919         if (one && two) {
1920                 *arg++ = pgm;
1921                 *arg++ = name;
1922                 *arg++ = temp[0].name;
1923                 *arg++ = temp[0].hex;
1924                 *arg++ = temp[0].mode;
1925                 *arg++ = temp[1].name;
1926                 *arg++ = temp[1].hex;
1927                 *arg++ = temp[1].mode;
1928                 if (other) {
1929                         *arg++ = other;
1930                         *arg++ = xfrm_msg;
1931                 }
1932         } else {
1933                 *arg++ = pgm;
1934                 *arg++ = name;
1935         }
1936         *arg = NULL;
1937         fflush(NULL);
1938         retval = run_command_v_opt(spawn_arg, 0);
1939         remove_tempfile();
1940         if (retval) {
1941                 fprintf(stderr, "external diff died, stopping at %s.\n", name);
1942                 exit(1);
1943         }
1944 }
1945
1946 static void run_diff_cmd(const char *pgm,
1947                          const char *name,
1948                          const char *other,
1949                          const char *attr_path,
1950                          struct diff_filespec *one,
1951                          struct diff_filespec *two,
1952                          const char *xfrm_msg,
1953                          struct diff_options *o,
1954                          int complete_rewrite)
1955 {
1956         if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
1957                 pgm = NULL;
1958         else {
1959                 struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
1960                 if (drv && drv->external)
1961                         pgm = drv->external;
1962         }
1963
1964         if (pgm) {
1965                 run_external_diff(pgm, name, other, one, two, xfrm_msg,
1966                                   complete_rewrite);
1967                 return;
1968         }
1969         if (one && two)
1970                 builtin_diff(name, other ? other : name,
1971                              one, two, xfrm_msg, o, complete_rewrite);
1972         else
1973                 fprintf(o->file, "* Unmerged path %s\n", name);
1974 }
1975
1976 static void diff_fill_sha1_info(struct diff_filespec *one)
1977 {
1978         if (DIFF_FILE_VALID(one)) {
1979                 if (!one->sha1_valid) {
1980                         struct stat st;
1981                         if (!strcmp(one->path, "-")) {
1982                                 hashcpy(one->sha1, null_sha1);
1983                                 return;
1984                         }
1985                         if (lstat(one->path, &st) < 0)
1986                                 die("stat %s", one->path);
1987                         if (index_path(one->sha1, one->path, &st, 0))
1988                                 die("cannot hash %s\n", one->path);
1989                 }
1990         }
1991         else
1992                 hashclr(one->sha1);
1993 }
1994
1995 static int similarity_index(struct diff_filepair *p)
1996 {
1997         return p->score * 100 / MAX_SCORE;
1998 }
1999
2000 static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
2001 {
2002         /* Strip the prefix but do not molest /dev/null and absolute paths */
2003         if (*namep && **namep != '/')
2004                 *namep += prefix_length;
2005         if (*otherp && **otherp != '/')
2006                 *otherp += prefix_length;
2007 }
2008
2009 static void run_diff(struct diff_filepair *p, struct diff_options *o)
2010 {
2011         const char *pgm = external_diff();
2012         struct strbuf msg;
2013         char *xfrm_msg;
2014         struct diff_filespec *one = p->one;
2015         struct diff_filespec *two = p->two;
2016         const char *name;
2017         const char *other;
2018         const char *attr_path;
2019         int complete_rewrite = 0;
2020
2021         name  = p->one->path;
2022         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
2023         attr_path = name;
2024         if (o->prefix_length)
2025                 strip_prefix(o->prefix_length, &name, &other);
2026
2027         if (DIFF_PAIR_UNMERGED(p)) {
2028                 run_diff_cmd(pgm, name, NULL, attr_path,
2029                              NULL, NULL, NULL, o, 0);
2030                 return;
2031         }
2032
2033         diff_fill_sha1_info(one);
2034         diff_fill_sha1_info(two);
2035
2036         strbuf_init(&msg, PATH_MAX * 2 + 300);
2037         switch (p->status) {
2038         case DIFF_STATUS_COPIED:
2039                 strbuf_addf(&msg, "similarity index %d%%", similarity_index(p));
2040                 strbuf_addstr(&msg, "\ncopy from ");
2041                 quote_c_style(name, &msg, NULL, 0);
2042                 strbuf_addstr(&msg, "\ncopy to ");
2043                 quote_c_style(other, &msg, NULL, 0);
2044                 strbuf_addch(&msg, '\n');
2045                 break;
2046         case DIFF_STATUS_RENAMED:
2047                 strbuf_addf(&msg, "similarity index %d%%", similarity_index(p));
2048                 strbuf_addstr(&msg, "\nrename from ");
2049                 quote_c_style(name, &msg, NULL, 0);
2050                 strbuf_addstr(&msg, "\nrename to ");
2051                 quote_c_style(other, &msg, NULL, 0);
2052                 strbuf_addch(&msg, '\n');
2053                 break;
2054         case DIFF_STATUS_MODIFIED:
2055                 if (p->score) {
2056                         strbuf_addf(&msg, "dissimilarity index %d%%\n",
2057                                         similarity_index(p));
2058                         complete_rewrite = 1;
2059                         break;
2060                 }
2061                 /* fallthru */
2062         default:
2063                 /* nothing */
2064                 ;
2065         }
2066
2067         if (hashcmp(one->sha1, two->sha1)) {
2068                 int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
2069
2070                 if (DIFF_OPT_TST(o, BINARY)) {
2071                         mmfile_t mf;
2072                         if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
2073                             (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
2074                                 abbrev = 40;
2075                 }
2076                 strbuf_addf(&msg, "index %.*s..%.*s",
2077                                 abbrev, sha1_to_hex(one->sha1),
2078                                 abbrev, sha1_to_hex(two->sha1));
2079                 if (one->mode == two->mode)
2080                         strbuf_addf(&msg, " %06o", one->mode);
2081                 strbuf_addch(&msg, '\n');
2082         }
2083
2084         if (msg.len)
2085                 strbuf_setlen(&msg, msg.len - 1);
2086         xfrm_msg = msg.len ? msg.buf : NULL;
2087
2088         if (!pgm &&
2089             DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
2090             (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
2091                 /* a filepair that changes between file and symlink
2092                  * needs to be split into deletion and creation.
2093                  */
2094                 struct diff_filespec *null = alloc_filespec(two->path);
2095                 run_diff_cmd(NULL, name, other, attr_path,
2096                              one, null, xfrm_msg, o, 0);
2097                 free(null);
2098                 null = alloc_filespec(one->path);
2099                 run_diff_cmd(NULL, name, other, attr_path,
2100                              null, two, xfrm_msg, o, 0);
2101                 free(null);
2102         }
2103         else
2104                 run_diff_cmd(pgm, name, other, attr_path,
2105                              one, two, xfrm_msg, o, complete_rewrite);
2106
2107         strbuf_release(&msg);
2108 }
2109
2110 static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
2111                          struct diffstat_t *diffstat)
2112 {
2113         const char *name;
2114         const char *other;
2115         int complete_rewrite = 0;
2116
2117         if (DIFF_PAIR_UNMERGED(p)) {
2118                 /* unmerged */
2119                 builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, 0);
2120                 return;
2121         }
2122
2123         name = p->one->path;
2124         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
2125
2126         if (o->prefix_length)
2127                 strip_prefix(o->prefix_length, &name, &other);
2128
2129         diff_fill_sha1_info(p->one);
2130         diff_fill_sha1_info(p->two);
2131
2132         if (p->status == DIFF_STATUS_MODIFIED && p->score)
2133                 complete_rewrite = 1;
2134         builtin_diffstat(name, other, p->one, p->two, diffstat, o, complete_rewrite);
2135 }
2136
2137 static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
2138 {
2139         const char *name;
2140         const char *other;
2141         const char *attr_path;
2142
2143         if (DIFF_PAIR_UNMERGED(p)) {
2144                 /* unmerged */
2145                 return;
2146         }
2147
2148         name = p->one->path;
2149         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
2150         attr_path = other ? other : name;
2151
2152         if (o->prefix_length)
2153                 strip_prefix(o->prefix_length, &name, &other);
2154
2155         diff_fill_sha1_info(p->one);
2156         diff_fill_sha1_info(p->two);
2157
2158         builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
2159 }
2160
2161 void diff_setup(struct diff_options *options)
2162 {
2163         memset(options, 0, sizeof(*options));
2164
2165         options->file = stdout;
2166
2167         options->line_termination = '\n';
2168         options->break_opt = -1;
2169         options->rename_limit = -1;
2170         options->dirstat_percent = 3;
2171         DIFF_OPT_CLR(options, DIRSTAT_CUMULATIVE);
2172         options->context = 3;
2173
2174         options->change = diff_change;
2175         options->add_remove = diff_addremove;
2176         if (diff_use_color_default > 0)
2177                 DIFF_OPT_SET(options, COLOR_DIFF);
2178         else
2179                 DIFF_OPT_CLR(options, COLOR_DIFF);
2180         options->detect_rename = diff_detect_rename_default;
2181
2182         if (!diff_mnemonic_prefix) {
2183                 options->a_prefix = "a/";
2184                 options->b_prefix = "b/";
2185         }
2186 }
2187
2188 int diff_setup_done(struct diff_options *options)
2189 {
2190         int count = 0;
2191
2192         if (options->output_format & DIFF_FORMAT_NAME)
2193                 count++;
2194         if (options->output_format & DIFF_FORMAT_NAME_STATUS)
2195                 count++;
2196         if (options->output_format & DIFF_FORMAT_CHECKDIFF)
2197                 count++;
2198         if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
2199                 count++;
2200         if (count > 1)
2201                 die("--name-only, --name-status, --check and -s are mutually exclusive");
2202
2203         if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
2204                 options->detect_rename = DIFF_DETECT_COPY;
2205
2206         if (!DIFF_OPT_TST(options, RELATIVE_NAME))
2207                 options->prefix = NULL;
2208         if (options->prefix)
2209                 options->prefix_length = strlen(options->prefix);
2210         else
2211                 options->prefix_length = 0;
2212
2213         if (options->output_format & (DIFF_FORMAT_NAME |
2214                                       DIFF_FORMAT_NAME_STATUS |
2215                                       DIFF_FORMAT_CHECKDIFF |
2216                                       DIFF_FORMAT_NO_OUTPUT))
2217                 options->output_format &= ~(DIFF_FORMAT_RAW |
2218                                             DIFF_FORMAT_NUMSTAT |
2219                                             DIFF_FORMAT_DIFFSTAT |
2220                                             DIFF_FORMAT_SHORTSTAT |
2221                                             DIFF_FORMAT_DIRSTAT |
2222                                             DIFF_FORMAT_SUMMARY |
2223                                             DIFF_FORMAT_PATCH);
2224
2225         /*
2226          * These cases always need recursive; we do not drop caller-supplied
2227          * recursive bits for other formats here.
2228          */
2229         if (options->output_format & (DIFF_FORMAT_PATCH |
2230                                       DIFF_FORMAT_NUMSTAT |
2231                                       DIFF_FORMAT_DIFFSTAT |
2232                                       DIFF_FORMAT_SHORTSTAT |
2233                                       DIFF_FORMAT_DIRSTAT |
2234                                       DIFF_FORMAT_SUMMARY |
2235                                       DIFF_FORMAT_CHECKDIFF))
2236                 DIFF_OPT_SET(options, RECURSIVE);
2237         /*
2238          * Also pickaxe would not work very well if you do not say recursive
2239          */
2240         if (options->pickaxe)
2241                 DIFF_OPT_SET(options, RECURSIVE);
2242
2243         if (options->detect_rename && options->rename_limit < 0)
2244                 options->rename_limit = diff_rename_limit_default;
2245         if (options->setup & DIFF_SETUP_USE_CACHE) {
2246                 if (!active_cache)
2247                         /* read-cache does not die even when it fails
2248                          * so it is safe for us to do this here.  Also
2249                          * it does not smudge active_cache or active_nr
2250                          * when it fails, so we do not have to worry about
2251                          * cleaning it up ourselves either.
2252                          */
2253                         read_cache();
2254         }
2255         if (options->abbrev <= 0 || 40 < options->abbrev)
2256                 options->abbrev = 40; /* full */
2257
2258         /*
2259          * It does not make sense to show the first hit we happened
2260          * to have found.  It does not make sense not to return with
2261          * exit code in such a case either.
2262          */
2263         if (DIFF_OPT_TST(options, QUIET)) {
2264                 options->output_format = DIFF_FORMAT_NO_OUTPUT;
2265                 DIFF_OPT_SET(options, EXIT_WITH_STATUS);
2266         }
2267
2268         return 0;
2269 }
2270
2271 static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
2272 {
2273         char c, *eq;
2274         int len;
2275
2276         if (*arg != '-')
2277                 return 0;
2278         c = *++arg;
2279         if (!c)
2280                 return 0;
2281         if (c == arg_short) {
2282                 c = *++arg;
2283                 if (!c)
2284                         return 1;
2285                 if (val && isdigit(c)) {
2286                         char *end;
2287                         int n = strtoul(arg, &end, 10);
2288                         if (*end)
2289                                 return 0;
2290                         *val = n;
2291                         return 1;
2292                 }
2293                 return 0;
2294         }
2295         if (c != '-')
2296                 return 0;
2297         arg++;
2298         eq = strchr(arg, '=');
2299         if (eq)
2300                 len = eq - arg;
2301         else
2302                 len = strlen(arg);
2303         if (!len || strncmp(arg, arg_long, len))
2304                 return 0;
2305         if (eq) {
2306                 int n;
2307                 char *end;
2308                 if (!isdigit(*++eq))
2309                         return 0;
2310                 n = strtoul(eq, &end, 10);
2311                 if (*end)
2312                         return 0;
2313                 *val = n;
2314         }
2315         return 1;
2316 }
2317
2318 static int diff_scoreopt_parse(const char *opt);
2319
2320 int diff_opt_parse(struct diff_options *options, const char **av, int ac)
2321 {
2322         const char *arg = av[0];
2323
2324         /* Output format options */
2325         if (!strcmp(arg, "-p") || !strcmp(arg, "-u"))
2326                 options->output_format |= DIFF_FORMAT_PATCH;
2327         else if (opt_arg(arg, 'U', "unified", &options->context))
2328                 options->output_format |= DIFF_FORMAT_PATCH;
2329         else if (!strcmp(arg, "--raw"))
2330                 options->output_format |= DIFF_FORMAT_RAW;
2331         else if (!strcmp(arg, "--patch-with-raw"))
2332                 options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_RAW;
2333         else if (!strcmp(arg, "--numstat"))
2334                 options->output_format |= DIFF_FORMAT_NUMSTAT;
2335         else if (!strcmp(arg, "--shortstat"))
2336                 options->output_format |= DIFF_FORMAT_SHORTSTAT;
2337         else if (opt_arg(arg, 'X', "dirstat", &options->dirstat_percent))
2338                 options->output_format |= DIFF_FORMAT_DIRSTAT;
2339         else if (!strcmp(arg, "--cumulative")) {
2340                 options->output_format |= DIFF_FORMAT_DIRSTAT;
2341                 DIFF_OPT_SET(options, DIRSTAT_CUMULATIVE);
2342         } else if (opt_arg(arg, 0, "dirstat-by-file",
2343                            &options->dirstat_percent)) {
2344                 options->output_format |= DIFF_FORMAT_DIRSTAT;
2345                 DIFF_OPT_SET(options, DIRSTAT_BY_FILE);
2346         }
2347         else if (!strcmp(arg, "--check"))
2348                 options->output_format |= DIFF_FORMAT_CHECKDIFF;
2349         else if (!strcmp(arg, "--summary"))
2350                 options->output_format |= DIFF_FORMAT_SUMMARY;
2351         else if (!strcmp(arg, "--patch-with-stat"))
2352                 options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_DIFFSTAT;
2353         else if (!strcmp(arg, "--name-only"))
2354                 options->output_format |= DIFF_FORMAT_NAME;
2355         else if (!strcmp(arg, "--name-status"))
2356                 options->output_format |= DIFF_FORMAT_NAME_STATUS;
2357         else if (!strcmp(arg, "-s"))
2358                 options->output_format |= DIFF_FORMAT_NO_OUTPUT;
2359         else if (!prefixcmp(arg, "--stat")) {
2360                 char *end;
2361                 int width = options->stat_width;
2362                 int name_width = options->stat_name_width;
2363                 arg += 6;
2364                 end = (char *)arg;
2365
2366                 switch (*arg) {
2367                 case '-':
2368                         if (!prefixcmp(arg, "-width="))
2369                                 width = strtoul(arg + 7, &end, 10);
2370                         else if (!prefixcmp(arg, "-name-width="))
2371                                 name_width = strtoul(arg + 12, &end, 10);
2372                         break;
2373                 case '=':
2374                         width = strtoul(arg+1, &end, 10);
2375                         if (*end == ',')
2376                                 name_width = strtoul(end+1, &end, 10);
2377                 }
2378
2379                 /* Important! This checks all the error cases! */
2380                 if (*end)
2381                         return 0;
2382                 options->output_format |= DIFF_FORMAT_DIFFSTAT;
2383                 options->stat_name_width = name_width;
2384                 options->stat_width = width;
2385         }
2386
2387         /* renames options */
2388         else if (!prefixcmp(arg, "-B")) {
2389                 if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
2390                         return -1;
2391         }
2392         else if (!prefixcmp(arg, "-M")) {
2393                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
2394                         return -1;
2395                 options->detect_rename = DIFF_DETECT_RENAME;
2396         }
2397         else if (!prefixcmp(arg, "-C")) {
2398                 if (options->detect_rename == DIFF_DETECT_COPY)
2399                         DIFF_OPT_SET(options, FIND_COPIES_HARDER);
2400                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
2401                         return -1;
2402                 options->detect_rename = DIFF_DETECT_COPY;
2403         }
2404         else if (!strcmp(arg, "--no-renames"))
2405                 options->detect_rename = 0;
2406         else if (!strcmp(arg, "--relative"))
2407                 DIFF_OPT_SET(options, RELATIVE_NAME);
2408         else if (!prefixcmp(arg, "--relative=")) {
2409                 DIFF_OPT_SET(options, RELATIVE_NAME);
2410                 options->prefix = arg + 11;
2411         }
2412
2413         /* xdiff options */
2414         else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
2415                 options->xdl_opts |= XDF_IGNORE_WHITESPACE;
2416         else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
2417                 options->xdl_opts |= XDF_IGNORE_WHITESPACE_CHANGE;
2418         else if (!strcmp(arg, "--ignore-space-at-eol"))
2419                 options->xdl_opts |= XDF_IGNORE_WHITESPACE_AT_EOL;
2420
2421         /* flags options */
2422         else if (!strcmp(arg, "--binary")) {
2423                 options->output_format |= DIFF_FORMAT_PATCH;
2424                 DIFF_OPT_SET(options, BINARY);
2425         }
2426         else if (!strcmp(arg, "--full-index"))
2427                 DIFF_OPT_SET(options, FULL_INDEX);
2428         else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
2429                 DIFF_OPT_SET(options, TEXT);
2430         else if (!strcmp(arg, "-R"))
2431                 DIFF_OPT_SET(options, REVERSE_DIFF);
2432         else if (!strcmp(arg, "--find-copies-harder"))
2433                 DIFF_OPT_SET(options, FIND_COPIES_HARDER);
2434         else if (!strcmp(arg, "--follow"))
2435                 DIFF_OPT_SET(options, FOLLOW_RENAMES);
2436         else if (!strcmp(arg, "--color"))
2437                 DIFF_OPT_SET(options, COLOR_DIFF);
2438         else if (!strcmp(arg, "--no-color"))
2439                 DIFF_OPT_CLR(options, COLOR_DIFF);
2440         else if (!strcmp(arg, "--color-words"))
2441                 options->flags |= DIFF_OPT_COLOR_DIFF | DIFF_OPT_COLOR_DIFF_WORDS;
2442         else if (!strcmp(arg, "--exit-code"))
2443                 DIFF_OPT_SET(options, EXIT_WITH_STATUS);
2444         else if (!strcmp(arg, "--quiet"))
2445                 DIFF_OPT_SET(options, QUIET);
2446         else if (!strcmp(arg, "--ext-diff"))
2447                 DIFF_OPT_SET(options, ALLOW_EXTERNAL);
2448         else if (!strcmp(arg, "--no-ext-diff"))
2449                 DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
2450         else if (!strcmp(arg, "--ignore-submodules"))
2451                 DIFF_OPT_SET(options, IGNORE_SUBMODULES);
2452
2453         /* misc options */
2454         else if (!strcmp(arg, "-z"))
2455                 options->line_termination = 0;
2456         else if (!prefixcmp(arg, "-l"))
2457                 options->rename_limit = strtoul(arg+2, NULL, 10);
2458         else if (!prefixcmp(arg, "-S"))
2459                 options->pickaxe = arg + 2;
2460         else if (!strcmp(arg, "--pickaxe-all"))
2461                 options->pickaxe_opts = DIFF_PICKAXE_ALL;
2462         else if (!strcmp(arg, "--pickaxe-regex"))
2463                 options->pickaxe_opts = DIFF_PICKAXE_REGEX;
2464         else if (!prefixcmp(arg, "-O"))
2465                 options->orderfile = arg + 2;
2466         else if (!prefixcmp(arg, "--diff-filter="))
2467                 options->filter = arg + 14;
2468         else if (!strcmp(arg, "--abbrev"))
2469                 options->abbrev = DEFAULT_ABBREV;
2470         else if (!prefixcmp(arg, "--abbrev=")) {
2471                 options->abbrev = strtoul(arg + 9, NULL, 10);
2472                 if (options->abbrev < MINIMUM_ABBREV)
2473                         options->abbrev = MINIMUM_ABBREV;
2474                 else if (40 < options->abbrev)
2475                         options->abbrev = 40;
2476         }
2477         else if (!prefixcmp(arg, "--src-prefix="))
2478                 options->a_prefix = arg + 13;
2479         else if (!prefixcmp(arg, "--dst-prefix="))
2480                 options->b_prefix = arg + 13;
2481         else if (!strcmp(arg, "--no-prefix"))
2482                 options->a_prefix = options->b_prefix = "";
2483         else if (!prefixcmp(arg, "--output=")) {
2484                 options->file = fopen(arg + strlen("--output="), "w");
2485                 options->close_file = 1;
2486         } else
2487                 return 0;
2488         return 1;
2489 }
2490
2491 static int parse_num(const char **cp_p)
2492 {
2493         unsigned long num, scale;
2494         int ch, dot;
2495         const char *cp = *cp_p;
2496
2497         num = 0;
2498         scale = 1;
2499         dot = 0;
2500         for(;;) {
2501                 ch = *cp;
2502                 if ( !dot && ch == '.' ) {
2503                         scale = 1;
2504                         dot = 1;
2505                 } else if ( ch == '%' ) {
2506                         scale = dot ? scale*100 : 100;
2507                         cp++;   /* % is always at the end */
2508                         break;
2509                 } else if ( ch >= '0' && ch <= '9' ) {
2510                         if ( scale < 100000 ) {
2511                                 scale *= 10;
2512                                 num = (num*10) + (ch-'0');
2513                         }
2514                 } else {
2515                         break;
2516                 }
2517                 cp++;
2518         }
2519         *cp_p = cp;
2520
2521         /* user says num divided by scale and we say internally that
2522          * is MAX_SCORE * num / scale.
2523          */
2524         return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
2525 }
2526
2527 static int diff_scoreopt_parse(const char *opt)
2528 {
2529         int opt1, opt2, cmd;
2530
2531         if (*opt++ != '-')
2532                 return -1;
2533         cmd = *opt++;
2534         if (cmd != 'M' && cmd != 'C' && cmd != 'B')
2535                 return -1; /* that is not a -M, -C nor -B option */
2536
2537         opt1 = parse_num(&opt);
2538         if (cmd != 'B')
2539                 opt2 = 0;
2540         else {
2541                 if (*opt == 0)
2542                         opt2 = 0;
2543                 else if (*opt != '/')
2544                         return -1; /* we expect -B80/99 or -B80 */
2545                 else {
2546                         opt++;
2547                         opt2 = parse_num(&opt);
2548                 }
2549         }
2550         if (*opt != 0)
2551                 return -1;
2552         return opt1 | (opt2 << 16);
2553 }
2554
2555 struct diff_queue_struct diff_queued_diff;
2556
2557 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
2558 {
2559         if (queue->alloc <= queue->nr) {
2560                 queue->alloc = alloc_nr(queue->alloc);
2561                 queue->queue = xrealloc(queue->queue,
2562                                         sizeof(dp) * queue->alloc);
2563         }
2564         queue->queue[queue->nr++] = dp;
2565 }
2566
2567 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
2568                                  struct diff_filespec *one,
2569                                  struct diff_filespec *two)
2570 {
2571         struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
2572         dp->one = one;
2573         dp->two = two;
2574         if (queue)
2575                 diff_q(queue, dp);
2576         return dp;
2577 }
2578
2579 void diff_free_filepair(struct diff_filepair *p)
2580 {
2581         free_filespec(p->one);
2582         free_filespec(p->two);
2583         free(p);
2584 }
2585
2586 /* This is different from find_unique_abbrev() in that
2587  * it stuffs the result with dots for alignment.
2588  */
2589 const char *diff_unique_abbrev(const unsigned char *sha1, int len)
2590 {
2591         int abblen;
2592         const char *abbrev;
2593         if (len == 40)
2594                 return sha1_to_hex(sha1);
2595
2596         abbrev = find_unique_abbrev(sha1, len);
2597         abblen = strlen(abbrev);
2598         if (abblen < 37) {
2599                 static char hex[41];
2600                 if (len < abblen && abblen <= len + 2)
2601                         sprintf(hex, "%s%.*s", abbrev, len+3-abblen, "..");
2602                 else
2603                         sprintf(hex, "%s...", abbrev);
2604                 return hex;
2605         }
2606         return sha1_to_hex(sha1);
2607 }
2608
2609 static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
2610 {
2611         int line_termination = opt->line_termination;
2612         int inter_name_termination = line_termination ? '\t' : '\0';
2613
2614         if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
2615                 fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
2616                         diff_unique_abbrev(p->one->sha1, opt->abbrev));
2617                 fprintf(opt->file, "%s ", diff_unique_abbrev(p->two->sha1, opt->abbrev));
2618         }
2619         if (p->score) {
2620                 fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
2621                         inter_name_termination);
2622         } else {
2623                 fprintf(opt->file, "%c%c", p->status, inter_name_termination);
2624         }
2625
2626         if (p->status == DIFF_STATUS_COPIED ||
2627             p->status == DIFF_STATUS_RENAMED) {
2628                 const char *name_a, *name_b;
2629                 name_a = p->one->path;
2630                 name_b = p->two->path;
2631                 strip_prefix(opt->prefix_length, &name_a, &name_b);
2632                 write_name_quoted(name_a, opt->file, inter_name_termination);
2633                 write_name_quoted(name_b, opt->file, line_termination);
2634         } else {
2635                 const char *name_a, *name_b;
2636                 name_a = p->one->mode ? p->one->path : p->two->path;
2637                 name_b = NULL;
2638                 strip_prefix(opt->prefix_length, &name_a, &name_b);
2639                 write_name_quoted(name_a, opt->file, line_termination);
2640         }
2641 }
2642
2643 int diff_unmodified_pair(struct diff_filepair *p)
2644 {
2645         /* This function is written stricter than necessary to support
2646          * the currently implemented transformers, but the idea is to
2647          * let transformers to produce diff_filepairs any way they want,
2648          * and filter and clean them up here before producing the output.
2649          */
2650         struct diff_filespec *one = p->one, *two = p->two;
2651
2652         if (DIFF_PAIR_UNMERGED(p))
2653                 return 0; /* unmerged is interesting */
2654
2655         /* deletion, addition, mode or type change
2656          * and rename are all interesting.
2657          */
2658         if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
2659             DIFF_PAIR_MODE_CHANGED(p) ||
2660             strcmp(one->path, two->path))
2661                 return 0;
2662
2663         /* both are valid and point at the same path.  that is, we are
2664          * dealing with a change.
2665          */
2666         if (one->sha1_valid && two->sha1_valid &&
2667             !hashcmp(one->sha1, two->sha1))
2668                 return 1; /* no change */
2669         if (!one->sha1_valid && !two->sha1_valid)
2670                 return 1; /* both look at the same file on the filesystem. */
2671         return 0;
2672 }
2673
2674 static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
2675 {
2676         if (diff_unmodified_pair(p))
2677                 return;
2678
2679         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
2680             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
2681                 return; /* no tree diffs in patch format */
2682
2683         run_diff(p, o);
2684 }
2685
2686 static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
2687                             struct diffstat_t *diffstat)
2688 {
2689         if (diff_unmodified_pair(p))
2690                 return;
2691
2692         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
2693             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
2694                 return; /* no tree diffs in patch format */
2695
2696         run_diffstat(p, o, diffstat);
2697 }
2698
2699 static void diff_flush_checkdiff(struct diff_filepair *p,
2700                 struct diff_options *o)
2701 {
2702         if (diff_unmodified_pair(p))
2703                 return;
2704
2705         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
2706             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
2707                 return; /* no tree diffs in patch format */
2708
2709         run_checkdiff(p, o);
2710 }
2711
2712 int diff_queue_is_empty(void)
2713 {
2714         struct diff_queue_struct *q = &diff_queued_diff;
2715         int i;
2716         for (i = 0; i < q->nr; i++)
2717                 if (!diff_unmodified_pair(q->queue[i]))
2718                         return 0;
2719         return 1;
2720 }
2721
2722 #if DIFF_DEBUG
2723 void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
2724 {
2725         fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
2726                 x, one ? one : "",
2727                 s->path,
2728                 DIFF_FILE_VALID(s) ? "valid" : "invalid",
2729                 s->mode,
2730                 s->sha1_valid ? sha1_to_hex(s->sha1) : "");
2731         fprintf(stderr, "queue[%d] %s size %lu flags %d\n",
2732                 x, one ? one : "",
2733                 s->size, s->xfrm_flags);
2734 }
2735
2736 void diff_debug_filepair(const struct diff_filepair *p, int i)
2737 {
2738         diff_debug_filespec(p->one, i, "one");
2739         diff_debug_filespec(p->two, i, "two");
2740         fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
2741                 p->score, p->status ? p->status : '?',
2742                 p->one->rename_used, p->broken_pair);
2743 }
2744
2745 void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
2746 {
2747         int i;
2748         if (msg)
2749                 fprintf(stderr, "%s\n", msg);
2750         fprintf(stderr, "q->nr = %d\n", q->nr);
2751         for (i = 0; i < q->nr; i++) {
2752                 struct diff_filepair *p = q->queue[i];
2753                 diff_debug_filepair(p, i);
2754         }
2755 }
2756 #endif
2757
2758 static void diff_resolve_rename_copy(void)
2759 {
2760         int i;
2761         struct diff_filepair *p;
2762         struct diff_queue_struct *q = &diff_queued_diff;
2763
2764         diff_debug_queue("resolve-rename-copy", q);
2765
2766         for (i = 0; i < q->nr; i++) {
2767                 p = q->queue[i];
2768                 p->status = 0; /* undecided */
2769                 if (DIFF_PAIR_UNMERGED(p))
2770                         p->status = DIFF_STATUS_UNMERGED;
2771                 else if (!DIFF_FILE_VALID(p->one))
2772                         p->status = DIFF_STATUS_ADDED;
2773                 else if (!DIFF_FILE_VALID(p->two))
2774                         p->status = DIFF_STATUS_DELETED;
2775                 else if (DIFF_PAIR_TYPE_CHANGED(p))
2776                         p->status = DIFF_STATUS_TYPE_CHANGED;
2777
2778                 /* from this point on, we are dealing with a pair
2779                  * whose both sides are valid and of the same type, i.e.
2780                  * either in-place edit or rename/copy edit.
2781                  */
2782                 else if (DIFF_PAIR_RENAME(p)) {
2783                         /*
2784                          * A rename might have re-connected a broken
2785                          * pair up, causing the pathnames to be the
2786                          * same again. If so, that's not a rename at
2787                          * all, just a modification..
2788                          *
2789                          * Otherwise, see if this source was used for
2790                          * multiple renames, in which case we decrement
2791                          * the count, and call it a copy.
2792                          */
2793                         if (!strcmp(p->one->path, p->two->path))
2794                                 p->status = DIFF_STATUS_MODIFIED;
2795                         else if (--p->one->rename_used > 0)
2796                                 p->status = DIFF_STATUS_COPIED;
2797                         else
2798                                 p->status = DIFF_STATUS_RENAMED;
2799                 }
2800                 else if (hashcmp(p->one->sha1, p->two->sha1) ||
2801                          p->one->mode != p->two->mode ||
2802                          is_null_sha1(p->one->sha1))
2803                         p->status = DIFF_STATUS_MODIFIED;
2804                 else {
2805                         /* This is a "no-change" entry and should not
2806                          * happen anymore, but prepare for broken callers.
2807                          */
2808                         error("feeding unmodified %s to diffcore",
2809                               p->one->path);
2810                         p->status = DIFF_STATUS_UNKNOWN;
2811                 }
2812         }
2813         diff_debug_queue("resolve-rename-copy done", q);
2814 }
2815
2816 static int check_pair_status(struct diff_filepair *p)
2817 {
2818         switch (p->status) {
2819         case DIFF_STATUS_UNKNOWN:
2820                 return 0;
2821         case 0:
2822                 die("internal error in diff-resolve-rename-copy");
2823         default:
2824                 return 1;
2825         }
2826 }
2827
2828 static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
2829 {
2830         int fmt = opt->output_format;
2831
2832         if (fmt & DIFF_FORMAT_CHECKDIFF)
2833                 diff_flush_checkdiff(p, opt);
2834         else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
2835                 diff_flush_raw(p, opt);
2836         else if (fmt & DIFF_FORMAT_NAME) {
2837                 const char *name_a, *name_b;
2838                 name_a = p->two->path;
2839                 name_b = NULL;
2840                 strip_prefix(opt->prefix_length, &name_a, &name_b);
2841                 write_name_quoted(name_a, opt->file, opt->line_termination);
2842         }
2843 }
2844
2845 static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
2846 {
2847         if (fs->mode)
2848                 fprintf(file, " %s mode %06o ", newdelete, fs->mode);
2849         else
2850                 fprintf(file, " %s ", newdelete);
2851         write_name_quoted(fs->path, file, '\n');
2852 }
2853
2854
2855 static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name)
2856 {
2857         if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
2858                 fprintf(file, " mode change %06o => %06o%c", p->one->mode, p->two->mode,
2859                         show_name ? ' ' : '\n');
2860                 if (show_name) {
2861                         write_name_quoted(p->two->path, file, '\n');
2862                 }
2863         }
2864 }
2865
2866 static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p)
2867 {
2868         char *names = pprint_rename(p->one->path, p->two->path);
2869
2870         fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
2871         free(names);
2872         show_mode_change(file, p, 0);
2873 }
2874
2875 static void diff_summary(FILE *file, struct diff_filepair *p)
2876 {
2877         switch(p->status) {
2878         case DIFF_STATUS_DELETED:
2879                 show_file_mode_name(file, "delete", p->one);
2880                 break;
2881         case DIFF_STATUS_ADDED:
2882                 show_file_mode_name(file, "create", p->two);
2883                 break;
2884         case DIFF_STATUS_COPIED:
2885                 show_rename_copy(file, "copy", p);
2886                 break;
2887         case DIFF_STATUS_RENAMED:
2888                 show_rename_copy(file, "rename", p);
2889                 break;
2890         default:
2891                 if (p->score) {
2892                         fputs(" rewrite ", file);
2893                         write_name_quoted(p->two->path, file, ' ');
2894                         fprintf(file, "(%d%%)\n", similarity_index(p));
2895                 }
2896                 show_mode_change(file, p, !p->score);
2897                 break;
2898         }
2899 }
2900
2901 struct patch_id_t {
2902         git_SHA_CTX *ctx;
2903         int patchlen;
2904 };
2905
2906 static int remove_space(char *line, int len)
2907 {
2908         int i;
2909         char *dst = line;
2910         unsigned char c;
2911
2912         for (i = 0; i < len; i++)
2913                 if (!isspace((c = line[i])))
2914                         *dst++ = c;
2915
2916         return dst - line;
2917 }
2918
2919 static void patch_id_consume(void *priv, char *line, unsigned long len)
2920 {
2921         struct patch_id_t *data = priv;
2922         int new_len;
2923
2924         /* Ignore line numbers when computing the SHA1 of the patch */
2925         if (!prefixcmp(line, "@@ -"))
2926                 return;
2927
2928         new_len = remove_space(line, len);
2929
2930         git_SHA1_Update(data->ctx, line, new_len);
2931         data->patchlen += new_len;
2932 }
2933
2934 /* returns 0 upon success, and writes result into sha1 */
2935 static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
2936 {
2937         struct diff_queue_struct *q = &diff_queued_diff;
2938         int i;
2939         git_SHA_CTX ctx;
2940         struct patch_id_t data;
2941         char buffer[PATH_MAX * 4 + 20];
2942
2943         git_SHA1_Init(&ctx);
2944         memset(&data, 0, sizeof(struct patch_id_t));
2945         data.ctx = &ctx;
2946
2947         for (i = 0; i < q->nr; i++) {
2948                 xpparam_t xpp;
2949                 xdemitconf_t xecfg;
2950                 xdemitcb_t ecb;
2951                 mmfile_t mf1, mf2;
2952                 struct diff_filepair *p = q->queue[i];
2953                 int len1, len2;
2954
2955                 memset(&xecfg, 0, sizeof(xecfg));
2956                 if (p->status == 0)
2957                         return error("internal diff status error");
2958                 if (p->status == DIFF_STATUS_UNKNOWN)
2959                         continue;
2960                 if (diff_unmodified_pair(p))
2961                         continue;
2962                 if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
2963                     (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
2964                         continue;
2965                 if (DIFF_PAIR_UNMERGED(p))
2966                         continue;
2967
2968                 diff_fill_sha1_info(p->one);
2969                 diff_fill_sha1_info(p->two);
2970                 if (fill_mmfile(&mf1, p->one) < 0 ||
2971                                 fill_mmfile(&mf2, p->two) < 0)
2972                         return error("unable to read files to diff");
2973
2974                 len1 = remove_space(p->one->path, strlen(p->one->path));
2975                 len2 = remove_space(p->two->path, strlen(p->two->path));
2976                 if (p->one->mode == 0)
2977                         len1 = snprintf(buffer, sizeof(buffer),
2978                                         "diff--gita/%.*sb/%.*s"
2979                                         "newfilemode%06o"
2980                                         "---/dev/null"
2981                                         "+++b/%.*s",
2982                                         len1, p->one->path,
2983                                         len2, p->two->path,
2984                                         p->two->mode,
2985                                         len2, p->two->path);
2986                 else if (p->two->mode == 0)
2987                         len1 = snprintf(buffer, sizeof(buffer),
2988                                         "diff--gita/%.*sb/%.*s"
2989                                         "deletedfilemode%06o"
2990                                         "---a/%.*s"
2991                                         "+++/dev/null",
2992                                         len1, p->one->path,
2993                                         len2, p->two->path,
2994                                         p->one->mode,
2995                                         len1, p->one->path);
2996                 else
2997                         len1 = snprintf(buffer, sizeof(buffer),
2998                                         "diff--gita/%.*sb/%.*s"
2999                                         "---a/%.*s"
3000                                         "+++b/%.*s",
3001                                         len1, p->one->path,
3002                                         len2, p->two->path,
3003                                         len1, p->one->path,
3004                                         len2, p->two->path);
3005                 git_SHA1_Update(&ctx, buffer, len1);
3006
3007                 xpp.flags = XDF_NEED_MINIMAL;
3008                 xecfg.ctxlen = 3;
3009                 xecfg.flags = XDL_EMIT_FUNCNAMES;
3010                 xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
3011                               &xpp, &xecfg, &ecb);
3012         }
3013
3014         git_SHA1_Final(sha1, &ctx);
3015         return 0;
3016 }
3017
3018 int diff_flush_patch_id(struct diff_options *options, unsigned char *sha1)
3019 {
3020         struct diff_queue_struct *q = &diff_queued_diff;
3021         int i;
3022         int result = diff_get_patch_id(options, sha1);
3023
3024         for (i = 0; i < q->nr; i++)
3025                 diff_free_filepair(q->queue[i]);
3026
3027         free(q->queue);
3028         q->queue = NULL;
3029         q->nr = q->alloc = 0;
3030
3031         return result;
3032 }
3033
3034 static int is_summary_empty(const struct diff_queue_struct *q)
3035 {
3036         int i;
3037
3038         for (i = 0; i < q->nr; i++) {
3039                 const struct diff_filepair *p = q->queue[i];
3040
3041                 switch (p->status) {
3042                 case DIFF_STATUS_DELETED:
3043                 case DIFF_STATUS_ADDED:
3044                 case DIFF_STATUS_COPIED:
3045                 case DIFF_STATUS_RENAMED:
3046                         return 0;
3047                 default:
3048                         if (p->score)
3049                                 return 0;
3050                         if (p->one->mode && p->two->mode &&
3051                             p->one->mode != p->two->mode)
3052                                 return 0;
3053                         break;
3054                 }
3055         }
3056         return 1;
3057 }
3058
3059 void diff_flush(struct diff_options *options)
3060 {
3061         struct diff_queue_struct *q = &diff_queued_diff;
3062         int i, output_format = options->output_format;
3063         int separator = 0;
3064
3065         /*
3066          * Order: raw, stat, summary, patch
3067          * or:    name/name-status/checkdiff (other bits clear)
3068          */
3069         if (!q->nr)
3070                 goto free_queue;
3071
3072         if (output_format & (DIFF_FORMAT_RAW |
3073                              DIFF_FORMAT_NAME |
3074                              DIFF_FORMAT_NAME_STATUS |
3075                              DIFF_FORMAT_CHECKDIFF)) {
3076                 for (i = 0; i < q->nr; i++) {
3077                         struct diff_filepair *p = q->queue[i];
3078                         if (check_pair_status(p))
3079                                 flush_one_pair(p, options);
3080                 }
3081                 separator++;
3082         }
3083
3084         if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT)) {
3085                 struct diffstat_t diffstat;
3086
3087                 memset(&diffstat, 0, sizeof(struct diffstat_t));
3088                 for (i = 0; i < q->nr; i++) {
3089                         struct diff_filepair *p = q->queue[i];
3090                         if (check_pair_status(p))
3091                                 diff_flush_stat(p, options, &diffstat);
3092                 }
3093                 if (output_format & DIFF_FORMAT_NUMSTAT)
3094                         show_numstat(&diffstat, options);
3095                 if (output_format & DIFF_FORMAT_DIFFSTAT)
3096                         show_stats(&diffstat, options);
3097                 if (output_format & DIFF_FORMAT_SHORTSTAT)
3098                         show_shortstats(&diffstat, options);
3099                 free_diffstat_info(&diffstat);
3100                 separator++;
3101         }
3102         if (output_format & DIFF_FORMAT_DIRSTAT)
3103                 show_dirstat(options);
3104
3105         if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
3106                 for (i = 0; i < q->nr; i++)
3107                         diff_summary(options->file, q->queue[i]);
3108                 separator++;
3109         }
3110
3111         if (output_format & DIFF_FORMAT_PATCH) {
3112                 if (separator) {
3113                         putc(options->line_termination, options->file);
3114                         if (options->stat_sep) {
3115                                 /* attach patch instead of inline */
3116                                 fputs(options->stat_sep, options->file);
3117                         }
3118                 }
3119
3120                 for (i = 0; i < q->nr; i++) {
3121                         struct diff_filepair *p = q->queue[i];
3122                         if (check_pair_status(p))
3123                                 diff_flush_patch(p, options);
3124                 }
3125         }
3126
3127         if (output_format & DIFF_FORMAT_CALLBACK)
3128                 options->format_callback(q, options, options->format_callback_data);
3129
3130         for (i = 0; i < q->nr; i++)
3131                 diff_free_filepair(q->queue[i]);
3132 free_queue:
3133         free(q->queue);
3134         q->queue = NULL;
3135         q->nr = q->alloc = 0;
3136         if (options->close_file)
3137                 fclose(options->file);
3138 }
3139
3140 static void diffcore_apply_filter(const char *filter)
3141 {
3142         int i;
3143         struct diff_queue_struct *q = &diff_queued_diff;
3144         struct diff_queue_struct outq;
3145         outq.queue = NULL;
3146         outq.nr = outq.alloc = 0;
3147
3148         if (!filter)
3149                 return;
3150
3151         if (strchr(filter, DIFF_STATUS_FILTER_AON)) {
3152                 int found;
3153                 for (i = found = 0; !found && i < q->nr; i++) {
3154                         struct diff_filepair *p = q->queue[i];
3155                         if (((p->status == DIFF_STATUS_MODIFIED) &&
3156                              ((p->score &&
3157                                strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
3158                               (!p->score &&
3159                                strchr(filter, DIFF_STATUS_MODIFIED)))) ||
3160                             ((p->status != DIFF_STATUS_MODIFIED) &&
3161                              strchr(filter, p->status)))
3162                                 found++;
3163                 }
3164                 if (found)
3165                         return;
3166
3167                 /* otherwise we will clear the whole queue
3168                  * by copying the empty outq at the end of this
3169                  * function, but first clear the current entries
3170                  * in the queue.
3171                  */
3172                 for (i = 0; i < q->nr; i++)
3173                         diff_free_filepair(q->queue[i]);
3174         }
3175         else {
3176                 /* Only the matching ones */
3177                 for (i = 0; i < q->nr; i++) {
3178                         struct diff_filepair *p = q->queue[i];
3179
3180                         if (((p->status == DIFF_STATUS_MODIFIED) &&
3181                              ((p->score &&
3182                                strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
3183                               (!p->score &&
3184                                strchr(filter, DIFF_STATUS_MODIFIED)))) ||
3185                             ((p->status != DIFF_STATUS_MODIFIED) &&
3186                              strchr(filter, p->status)))
3187                                 diff_q(&outq, p);
3188                         else
3189                                 diff_free_filepair(p);
3190                 }
3191         }
3192         free(q->queue);
3193         *q = outq;
3194 }
3195
3196 /* Check whether two filespecs with the same mode and size are identical */
3197 static int diff_filespec_is_identical(struct diff_filespec *one,
3198                                       struct diff_filespec *two)
3199 {
3200         if (S_ISGITLINK(one->mode))
3201                 return 0;
3202         if (diff_populate_filespec(one, 0))
3203                 return 0;
3204         if (diff_populate_filespec(two, 0))
3205                 return 0;
3206         return !memcmp(one->data, two->data, one->size);
3207 }
3208
3209 static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
3210 {
3211         int i;
3212         struct diff_queue_struct *q = &diff_queued_diff;
3213         struct diff_queue_struct outq;
3214         outq.queue = NULL;
3215         outq.nr = outq.alloc = 0;
3216
3217         for (i = 0; i < q->nr; i++) {
3218                 struct diff_filepair *p = q->queue[i];
3219
3220                 /*
3221                  * 1. Entries that come from stat info dirtyness
3222                  *    always have both sides (iow, not create/delete),
3223                  *    one side of the object name is unknown, with
3224                  *    the same mode and size.  Keep the ones that
3225                  *    do not match these criteria.  They have real
3226                  *    differences.
3227                  *
3228                  * 2. At this point, the file is known to be modified,
3229                  *    with the same mode and size, and the object
3230                  *    name of one side is unknown.  Need to inspect
3231                  *    the identical contents.
3232                  */
3233                 if (!DIFF_FILE_VALID(p->one) || /* (1) */
3234                     !DIFF_FILE_VALID(p->two) ||
3235                     (p->one->sha1_valid && p->two->sha1_valid) ||
3236                     (p->one->mode != p->two->mode) ||
3237                     diff_populate_filespec(p->one, 1) ||
3238                     diff_populate_filespec(p->two, 1) ||
3239                     (p->one->size != p->two->size) ||
3240                     !diff_filespec_is_identical(p->one, p->two)) /* (2) */
3241                         diff_q(&outq, p);
3242                 else {
3243                         /*
3244                          * The caller can subtract 1 from skip_stat_unmatch
3245                          * to determine how many paths were dirty only
3246                          * due to stat info mismatch.
3247                          */
3248                         if (!DIFF_OPT_TST(diffopt, NO_INDEX))
3249                                 diffopt->skip_stat_unmatch++;
3250                         diff_free_filepair(p);
3251                 }
3252         }
3253         free(q->queue);
3254         *q = outq;
3255 }
3256
3257 void diffcore_std(struct diff_options *options)
3258 {
3259         if (options->skip_stat_unmatch)
3260                 diffcore_skip_stat_unmatch(options);
3261         if (options->break_opt != -1)
3262                 diffcore_break(options->break_opt);
3263         if (options->detect_rename)
3264                 diffcore_rename(options);
3265         if (options->break_opt != -1)
3266                 diffcore_merge_broken();
3267         if (options->pickaxe)
3268                 diffcore_pickaxe(options->pickaxe, options->pickaxe_opts);
3269         if (options->orderfile)
3270                 diffcore_order(options->orderfile);
3271         diff_resolve_rename_copy();
3272         diffcore_apply_filter(options->filter);
3273
3274         if (diff_queued_diff.nr)
3275                 DIFF_OPT_SET(options, HAS_CHANGES);
3276         else
3277                 DIFF_OPT_CLR(options, HAS_CHANGES);
3278 }
3279
3280 int diff_result_code(struct diff_options *opt, int status)
3281 {
3282         int result = 0;
3283         if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
3284             !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
3285                 return status;
3286         if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
3287             DIFF_OPT_TST(opt, HAS_CHANGES))
3288                 result |= 01;
3289         if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
3290             DIFF_OPT_TST(opt, CHECK_FAILED))
3291                 result |= 02;
3292         return result;
3293 }
3294
3295 void diff_addremove(struct diff_options *options,
3296                     int addremove, unsigned mode,
3297                     const unsigned char *sha1,
3298                     const char *concatpath)
3299 {
3300         struct diff_filespec *one, *two;
3301
3302         if (DIFF_OPT_TST(options, IGNORE_SUBMODULES) && S_ISGITLINK(mode))
3303                 return;
3304
3305         /* This may look odd, but it is a preparation for
3306          * feeding "there are unchanged files which should
3307          * not produce diffs, but when you are doing copy
3308          * detection you would need them, so here they are"
3309          * entries to the diff-core.  They will be prefixed
3310          * with something like '=' or '*' (I haven't decided
3311          * which but should not make any difference).
3312          * Feeding the same new and old to diff_change()
3313          * also has the same effect.
3314          * Before the final output happens, they are pruned after
3315          * merged into rename/copy pairs as appropriate.
3316          */
3317         if (DIFF_OPT_TST(options, REVERSE_DIFF))
3318                 addremove = (addremove == '+' ? '-' :
3319                              addremove == '-' ? '+' : addremove);
3320
3321         if (options->prefix &&
3322             strncmp(concatpath, options->prefix, options->prefix_length))
3323                 return;
3324
3325         one = alloc_filespec(concatpath);
3326         two = alloc_filespec(concatpath);
3327
3328         if (addremove != '+')
3329                 fill_filespec(one, sha1, mode);
3330         if (addremove != '-')
3331                 fill_filespec(two, sha1, mode);
3332
3333         diff_queue(&diff_queued_diff, one, two);
3334         DIFF_OPT_SET(options, HAS_CHANGES);
3335 }
3336
3337 void diff_change(struct diff_options *options,
3338                  unsigned old_mode, unsigned new_mode,
3339                  const unsigned char *old_sha1,
3340                  const unsigned char *new_sha1,
3341                  const char *concatpath)
3342 {
3343         struct diff_filespec *one, *two;
3344
3345         if (DIFF_OPT_TST(options, IGNORE_SUBMODULES) && S_ISGITLINK(old_mode)
3346                         && S_ISGITLINK(new_mode))
3347                 return;
3348
3349         if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
3350                 unsigned tmp;
3351                 const unsigned char *tmp_c;
3352                 tmp = old_mode; old_mode = new_mode; new_mode = tmp;
3353                 tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
3354         }
3355
3356         if (options->prefix &&
3357             strncmp(concatpath, options->prefix, options->prefix_length))
3358                 return;
3359
3360         one = alloc_filespec(concatpath);
3361         two = alloc_filespec(concatpath);
3362         fill_filespec(one, old_sha1, old_mode);
3363         fill_filespec(two, new_sha1, new_mode);
3364
3365         diff_queue(&diff_queued_diff, one, two);
3366         DIFF_OPT_SET(options, HAS_CHANGES);
3367 }
3368
3369 void diff_unmerge(struct diff_options *options,
3370                   const char *path,
3371                   unsigned mode, const unsigned char *sha1)
3372 {
3373         struct diff_filespec *one, *two;
3374
3375         if (options->prefix &&
3376             strncmp(path, options->prefix, options->prefix_length))
3377                 return;
3378
3379         one = alloc_filespec(path);
3380         two = alloc_filespec(path);
3381         fill_filespec(one, sha1, mode);
3382         diff_queue(&diff_queued_diff, one, two)->is_unmerged = 1;
3383 }