git.oblomov.eu Git - git/blob - 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
  15 #ifdef NO_FAST_WORKING_DIRECTORY
  16 #define FAST_WORKING_DIRECTORY 0
  17 #else
  18 #define FAST_WORKING_DIRECTORY 1
  19 #endif
  20
  21 static int diff_detect_rename_default;
  22 static int diff_rename_limit_default = 100;
  23 int diff_use_color_default = -1;
  24 static const char *external_diff_cmd_cfg;
  25 int diff_auto_refresh_index = 1;
  26
  27 static char diff_colors[][COLOR_MAXLEN] = {
  28         "\033[m",       /* reset */
  29         "",             /* PLAIN (normal) */
  30         "\033[1m",      /* METAINFO (bold) */
  31         "\033[36m",     /* FRAGINFO (cyan) */
  32         "\033[31m",     /* OLD (red) */
  33         "\033[32m",     /* NEW (green) */
  34         "\033[33m",     /* COMMIT (yellow) */
  35         "\033[41m",     /* WHITESPACE (red background) */
  36 };
  37
  38 static int parse_diff_color_slot(const char *var, int ofs)
  39 {
  40         if (!strcasecmp(var+ofs, "plain"))
  41                 return DIFF_PLAIN;
  42         if (!strcasecmp(var+ofs, "meta"))
  43                 return DIFF_METAINFO;
  44         if (!strcasecmp(var+ofs, "frag"))
  45                 return DIFF_FRAGINFO;
  46         if (!strcasecmp(var+ofs, "old"))
  47                 return DIFF_FILE_OLD;
  48         if (!strcasecmp(var+ofs, "new"))
  49                 return DIFF_FILE_NEW;
  50         if (!strcasecmp(var+ofs, "commit"))
  51                 return DIFF_COMMIT;
  52         if (!strcasecmp(var+ofs, "whitespace"))
  53                 return DIFF_WHITESPACE;
  54         die("bad config variable '%s'", var);
  55 }
  56
  57 static struct ll_diff_driver {
  58         const char *name;
  59         struct ll_diff_driver *next;
  60         const char *cmd;
  61 } *user_diff, **user_diff_tail;
  62
  63 /*
  64  * Currently there is only "diff.<drivername>.command" variable;
  65  * because there are "diff.color.<slot>" variables, we are parsing
  66  * this in a bit convoluted way to allow low level diff driver
  67  * called "color".
  68  */
  69 static int parse_lldiff_command(const char *var, const char *ep, const char *value)
  70 {
  71         const char *name;
  72         int namelen;
  73         struct ll_diff_driver *drv;
  74
  75         name = var + 5;
  76         namelen = ep - name;
  77         for (drv = user_diff; drv; drv = drv->next)
  78                 if (!strncmp(drv->name, name, namelen) && !drv->name[namelen])
  79                         break;
  80         if (!drv) {
  81                 drv = xcalloc(1, sizeof(struct ll_diff_driver));
  82                 drv->name = xmemdupz(name, namelen);
  83                 if (!user_diff_tail)
  84                         user_diff_tail = &user_diff;
  85                 *user_diff_tail = drv;
  86                 user_diff_tail = &(drv->next);
  87         }
  88
  89         return git_config_string(&(drv->cmd), var, value);
  90 }
  91
  92 /*
  93  * 'diff.<what>.funcname' attribute can be specified in the configuration
  94  * to define a customized regexp to find the beginning of a function to
  95  * be used for hunk header lines of "diff -p" style output.
  96  */
  97 static struct funcname_pattern {
  98         char *name;
  99         char *pattern;
 100         struct funcname_pattern *next;
 101 } *funcname_pattern_list;
 102
 103 static int parse_funcname_pattern(const char *var, const char *ep, const char *value)
 104 {
 105         const char *name;
 106         int namelen;
 107         struct funcname_pattern *pp;
 108
 109         name = var + 5; /* "diff." */
 110         namelen = ep - name;
 111
 112         for (pp = funcname_pattern_list; pp; pp = pp->next)
 113                 if (!strncmp(pp->name, name, namelen) && !pp->name[namelen])
 114                         break;
 115         if (!pp) {
 116                 pp = xcalloc(1, sizeof(*pp));
 117                 pp->name = xmemdupz(name, namelen);
 118                 pp->next = funcname_pattern_list;
 119                 funcname_pattern_list = pp;
 120         }
 121         free(pp->pattern);
 122         pp->pattern = xstrdup(value);
 123         return 0;
 124 }
 125
 126 /*
 127  * These are to give UI layer defaults.
 128  * The core-level commands such as git-diff-files should
 129  * never be affected by the setting of diff.renames
 130  * the user happens to have in the configuration file.
 131  */
 132 int git_diff_ui_config(const char *var, const char *value)
 133 {
 134         if (!strcmp(var, "diff.renamelimit")) {
 135                 diff_rename_limit_default = git_config_int(var, value);
 136                 return 0;
 137         }
 138         if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 139                 diff_use_color_default = git_config_colorbool(var, value, -1);
 140                 return 0;
 141         }
 142         if (!strcmp(var, "diff.renames")) {
 143                 if (!value)
 144                         diff_detect_rename_default = DIFF_DETECT_RENAME;
 145                 else if (!strcasecmp(value, "copies") ||
 146                          !strcasecmp(value, "copy"))
 147                         diff_detect_rename_default = DIFF_DETECT_COPY;
 148                 else if (git_config_bool(var,value))
 149                         diff_detect_rename_default = DIFF_DETECT_RENAME;
 150                 return 0;
 151         }
 152         if (!strcmp(var, "diff.autorefreshindex")) {
 153                 diff_auto_refresh_index = git_config_bool(var, value);
 154                 return 0;
 155         }
 156         if (!strcmp(var, "diff.external")) {
 157                 if (!value)
 158                         return config_error_nonbool(var);
 159                 external_diff_cmd_cfg = xstrdup(value);
 160                 return 0;
 161         }
 162         if (!prefixcmp(var, "diff.")) {
 163                 const char *ep = strrchr(var, '.');
 164
 165                 if (ep != var + 4 && !strcmp(ep, ".command"))
 166                         return parse_lldiff_command(var, ep, value);
 167         }
 168
 169         return git_diff_basic_config(var, value);
 170 }
 171
 172 int git_diff_basic_config(const char *var, const char *value)
 173 {
 174         if (!prefixcmp(var, "diff.color.") || !prefixcmp(var, "color.diff.")) {
 175                 int slot = parse_diff_color_slot(var, 11);
 176                 if (!value)
 177                         return config_error_nonbool(var);
 178                 color_parse(value, var, diff_colors[slot]);
 179                 return 0;
 180         }
 181
 182         if (!prefixcmp(var, "diff.")) {
 183                 const char *ep = strrchr(var, '.');
 184                 if (ep != var + 4) {
 185                         if (!strcmp(ep, ".funcname")) {
 186                                 if (!value)
 187                                         return config_error_nonbool(var);
 188                                 return parse_funcname_pattern(var, ep, value);
 189                         }
 190                 }
 191         }
 192
 193         return git_color_default_config(var, value);
 194 }
 195
 196 static char *quote_two(const char *one, const char *two)
 197 {
 198         int need_one = quote_c_style(one, NULL, NULL, 1);
 199         int need_two = quote_c_style(two, NULL, NULL, 1);
 200         struct strbuf res;
 201
 202         strbuf_init(&res, 0);
 203         if (need_one + need_two) {
 204                 strbuf_addch(&res, '"');
 205                 quote_c_style(one, &res, NULL, 1);
 206                 quote_c_style(two, &res, NULL, 1);
 207                 strbuf_addch(&res, '"');
 208         } else {
 209                 strbuf_addstr(&res, one);
 210                 strbuf_addstr(&res, two);
 211         }
 212         return strbuf_detach(&res, NULL);
 213 }
 214
 215 static const char *external_diff(void)
 216 {
 217         static const char *external_diff_cmd = NULL;
 218         static int done_preparing = 0;
 219
 220         if (done_preparing)
 221                 return external_diff_cmd;
 222         external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 223         if (!external_diff_cmd)
 224                 external_diff_cmd = external_diff_cmd_cfg;
 225         done_preparing = 1;
 226         return external_diff_cmd;
 227 }
 228
 229 static struct diff_tempfile {
 230         const char *name; /* filename external diff should read from */
 231         char hex[41];
 232         char mode[10];
 233         char tmp_path[PATH_MAX];
 234 } diff_temp[2];
 235
 236 static int count_lines(const char *data, int size)
 237 {
 238         int count, ch, completely_empty = 1, nl_just_seen = 0;
 239         count = 0;
 240         while (0 < size--) {
 241                 ch = *data++;
 242                 if (ch == '\n') {
 243                         count++;
 244                         nl_just_seen = 1;
 245                         completely_empty = 0;
 246                 }
 247                 else {
 248                         nl_just_seen = 0;
 249                         completely_empty = 0;
 250                 }
 251         }
 252         if (completely_empty)
 253                 return 0;
 254         if (!nl_just_seen)
 255                 count++; /* no trailing newline */
 256         return count;
 257 }
 258
 259 static void print_line_count(FILE *file, int count)
 260 {
 261         switch (count) {
 262         case 0:
 263                 fprintf(file, "0,0");
 264                 break;
 265         case 1:
 266                 fprintf(file, "1");
 267                 break;
 268         default:
 269                 fprintf(file, "1,%d", count);
 270                 break;
 271         }
 272 }
 273
 274 static void copy_file_with_prefix(FILE *file,
 275                                   int prefix, const char *data, int size,
 276                                   const char *set, const char *reset)
 277 {
 278         int ch, nl_just_seen = 1;
 279         while (0 < size--) {
 280                 ch = *data++;
 281                 if (nl_just_seen) {
 282                         fputs(set, file);
 283                         putc(prefix, file);
 284                 }
 285                 if (ch == '\n') {
 286                         nl_just_seen = 1;
 287                         fputs(reset, file);
 288                 } else
 289                         nl_just_seen = 0;
 290                 putc(ch, file);
 291         }
 292         if (!nl_just_seen)
 293                 fprintf(file, "%s\n\\ No newline at end of file\n", reset);
 294 }
 295
 296 static void emit_rewrite_diff(const char *name_a,
 297                               const char *name_b,
 298                               struct diff_filespec *one,
 299                               struct diff_filespec *two,
 300                               struct diff_options *o)
 301 {
 302         int lc_a, lc_b;
 303         int color_diff = DIFF_OPT_TST(o, COLOR_DIFF);
 304         const char *name_a_tab, *name_b_tab;
 305         const char *metainfo = diff_get_color(color_diff, DIFF_METAINFO);
 306         const char *fraginfo = diff_get_color(color_diff, DIFF_FRAGINFO);
 307         const char *old = diff_get_color(color_diff, DIFF_FILE_OLD);
 308         const char *new = diff_get_color(color_diff, DIFF_FILE_NEW);
 309         const char *reset = diff_get_color(color_diff, DIFF_RESET);
 310         static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
 311
 312         name_a += (*name_a == '/');
 313         name_b += (*name_b == '/');
 314         name_a_tab = strchr(name_a, ' ') ? "\t" : "";
 315         name_b_tab = strchr(name_b, ' ') ? "\t" : "";
 316
 317         strbuf_reset(&a_name);
 318         strbuf_reset(&b_name);
 319         quote_two_c_style(&a_name, o->a_prefix, name_a, 0);
 320         quote_two_c_style(&b_name, o->b_prefix, name_b, 0);
 321
 322         diff_populate_filespec(one, 0);
 323         diff_populate_filespec(two, 0);
 324         lc_a = count_lines(one->data, one->size);
 325         lc_b = count_lines(two->data, two->size);
 326         fprintf(o->file,
 327                 "%s--- %s%s%s\n%s+++ %s%s%s\n%s@@ -",
 328                 metainfo, a_name.buf, name_a_tab, reset,
 329                 metainfo, b_name.buf, name_b_tab, reset, fraginfo);
 330         print_line_count(o->file, lc_a);
 331         fprintf(o->file, " +");
 332         print_line_count(o->file, lc_b);
 333         fprintf(o->file, " @@%s\n", reset);
 334         if (lc_a)
 335                 copy_file_with_prefix(o->file, '-', one->data, one->size, old, reset);
 336         if (lc_b)
 337                 copy_file_with_prefix(o->file, '+', two->data, two->size, new, reset);
 338 }
 339
 340 static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 341 {
 342         if (!DIFF_FILE_VALID(one)) {
 343                 mf->ptr = (char *)""; /* does not matter */
 344                 mf->size = 0;
 345                 return 0;
 346         }
 347         else if (diff_populate_filespec(one, 0))
 348                 return -1;
 349         mf->ptr = one->data;
 350         mf->size = one->size;
 351         return 0;
 352 }
 353
 354 struct diff_words_buffer {
 355         mmfile_t text;
 356         long alloc;
 357         long current; /* output pointer */
 358         int suppressed_newline;
 359 };
 360
 361 static void diff_words_append(char *line, unsigned long len,
 362                 struct diff_words_buffer *buffer)
 363 {
 364         if (buffer->text.size + len > buffer->alloc) {
 365                 buffer->alloc = (buffer->text.size + len) * 3 / 2;
 366                 buffer->text.ptr = xrealloc(buffer->text.ptr, buffer->alloc);
 367         }
 368         line++;
 369         len--;
 370         memcpy(buffer->text.ptr + buffer->text.size, line, len);
 371         buffer->text.size += len;
 372 }
 373
 374 struct diff_words_data {
 375         struct xdiff_emit_state xm;
 376         struct diff_words_buffer minus, plus;
 377         FILE *file;
 378 };
 379
 380 static void print_word(FILE *file, struct diff_words_buffer *buffer, int len, int color,
 381                 int suppress_newline)
 382 {
 383         const char *ptr;
 384         int eol = 0;
 385
 386         if (len == 0)
 387                 return;
 388
 389         ptr  = buffer->text.ptr + buffer->current;
 390         buffer->current += len;
 391
 392         if (ptr[len - 1] == '\n') {
 393                 eol = 1;
 394                 len--;
 395         }
 396
 397         fputs(diff_get_color(1, color), file);
 398         fwrite(ptr, len, 1, file);
 399         fputs(diff_get_color(1, DIFF_RESET), file);
 400
 401         if (eol) {
 402                 if (suppress_newline)
 403                         buffer->suppressed_newline = 1;
 404                 else
 405                         putc('\n', file);
 406         }
 407 }
 408
 409 static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
 410 {
 411         struct diff_words_data *diff_words = priv;
 412
 413         if (diff_words->minus.suppressed_newline) {
 414                 if (line[0] != '+')
 415                         putc('\n', diff_words->file);
 416                 diff_words->minus.suppressed_newline = 0;
 417         }
 418
 419         len--;
 420         switch (line[0]) {
 421                 case '-':
 422                         print_word(diff_words->file,
 423                                    &diff_words->minus, len, DIFF_FILE_OLD, 1);
 424                         break;
 425                 case '+':
 426                         print_word(diff_words->file,
 427                                    &diff_words->plus, len, DIFF_FILE_NEW, 0);
 428                         break;
 429                 case ' ':
 430                         print_word(diff_words->file,
 431                                    &diff_words->plus, len, DIFF_PLAIN, 0);
 432                         diff_words->minus.current += len;
 433                         break;
 434         }
 435 }
 436
 437 /* this executes the word diff on the accumulated buffers */
 438 static void diff_words_show(struct diff_words_data *diff_words)
 439 {
 440         xpparam_t xpp;
 441         xdemitconf_t xecfg;
 442         xdemitcb_t ecb;
 443         mmfile_t minus, plus;
 444         int i;
 445
 446         memset(&xecfg, 0, sizeof(xecfg));
 447         minus.size = diff_words->minus.text.size;
 448         minus.ptr = xmalloc(minus.size);
 449         memcpy(minus.ptr, diff_words->minus.text.ptr, minus.size);
 450         for (i = 0; i < minus.size; i++)
 451                 if (isspace(minus.ptr[i]))
 452                         minus.ptr[i] = '\n';
 453         diff_words->minus.current = 0;
 454
 455         plus.size = diff_words->plus.text.size;
 456         plus.ptr = xmalloc(plus.size);
 457         memcpy(plus.ptr, diff_words->plus.text.ptr, plus.size);
 458         for (i = 0; i < plus.size; i++)
 459                 if (isspace(plus.ptr[i]))
 460                         plus.ptr[i] = '\n';
 461         diff_words->plus.current = 0;
 462
 463         xpp.flags = XDF_NEED_MINIMAL;
 464         xecfg.ctxlen = diff_words->minus.alloc + diff_words->plus.alloc;
 465         ecb.outf = xdiff_outf;
 466         ecb.priv = diff_words;
 467         diff_words->xm.consume = fn_out_diff_words_aux;
 468         xdi_diff(&minus, &plus, &xpp, &xecfg, &ecb);
 469
 470         free(minus.ptr);
 471         free(plus.ptr);
 472         diff_words->minus.text.size = diff_words->plus.text.size = 0;
 473
 474         if (diff_words->minus.suppressed_newline) {
 475                 putc('\n', diff_words->file);
 476                 diff_words->minus.suppressed_newline = 0;
 477         }
 478 }
 479
 480 typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
 481
 482 struct emit_callback {
 483         struct xdiff_emit_state xm;
 484         int nparents, color_diff;
 485         unsigned ws_rule;
 486         sane_truncate_fn truncate;
 487         const char **label_path;
 488         struct diff_words_data *diff_words;
 489         int *found_changesp;
 490         FILE *file;
 491 };
 492
 493 static void free_diff_words_data(struct emit_callback *ecbdata)
 494 {
 495         if (ecbdata->diff_words) {
 496                 /* flush buffers */
 497                 if (ecbdata->diff_words->minus.text.size ||
 498                                 ecbdata->diff_words->plus.text.size)
 499                         diff_words_show(ecbdata->diff_words);
 500
 501                 free (ecbdata->diff_words->minus.text.ptr);
 502                 free (ecbdata->diff_words->plus.text.ptr);
 503                 free(ecbdata->diff_words);
 504                 ecbdata->diff_words = NULL;
 505         }
 506 }
 507
 508 const char *diff_get_color(int diff_use_color, enum color_diff ix)
 509 {
 510         if (diff_use_color)
 511                 return diff_colors[ix];
 512         return "";
 513 }
 514
 515 static void emit_line(FILE *file, const char *set, const char *reset, const char *line, int len)
 516 {
 517         fputs(set, file);
 518         fwrite(line, len, 1, file);
 519         fputs(reset, file);
 520 }
 521
 522 static void emit_add_line(const char *reset, struct emit_callback *ecbdata, const char *line, int len)
 523 {
 524         const char *ws = diff_get_color(ecbdata->color_diff, DIFF_WHITESPACE);
 525         const char *set = diff_get_color(ecbdata->color_diff, DIFF_FILE_NEW);
 526
 527         if (!*ws)
 528                 emit_line(ecbdata->file, set, reset, line, len);
 529         else {
 530                 /* Emit just the prefix, then the rest. */
 531                 emit_line(ecbdata->file, set, reset, line, ecbdata->nparents);
 532                 (void)check_and_emit_line(line + ecbdata->nparents,
 533                     len - ecbdata->nparents, ecbdata->ws_rule,
 534                     ecbdata->file, set, reset, ws);
 535         }
 536 }
 537
 538 static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
 539 {
 540         const char *cp;
 541         unsigned long allot;
 542         size_t l = len;
 543
 544         if (ecb->truncate)
 545                 return ecb->truncate(line, len);
 546         cp = line;
 547         allot = l;
 548         while (0 < l) {
 549                 (void) utf8_width(&cp, &l);
 550                 if (!cp)
 551                         break; /* truncated in the middle? */
 552         }
 553         return allot - l;
 554 }
 555
 556 static void fn_out_consume(void *priv, char *line, unsigned long len)
 557 {
 558         int i;
 559         int color;
 560         struct emit_callback *ecbdata = priv;
 561         const char *meta = diff_get_color(ecbdata->color_diff, DIFF_METAINFO);
 562         const char *plain = diff_get_color(ecbdata->color_diff, DIFF_PLAIN);
 563         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
 564
 565         *(ecbdata->found_changesp) = 1;
 566
 567         if (ecbdata->label_path[0]) {
 568                 const char *name_a_tab, *name_b_tab;
 569
 570                 name_a_tab = strchr(ecbdata->label_path[0], ' ') ? "\t" : "";
 571                 name_b_tab = strchr(ecbdata->label_path[1], ' ') ? "\t" : "";
 572
 573                 fprintf(ecbdata->file, "%s--- %s%s%s\n",
 574                         meta, ecbdata->label_path[0], reset, name_a_tab);
 575                 fprintf(ecbdata->file, "%s+++ %s%s%s\n",
 576                         meta, ecbdata->label_path[1], reset, name_b_tab);
 577                 ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
 578         }
 579
 580         /* This is not really necessary for now because
 581          * this codepath only deals with two-way diffs.
 582          */
 583         for (i = 0; i < len && line[i] == '@'; i++)
 584                 ;
 585         if (2 <= i && i < len && line[i] == ' ') {
 586                 ecbdata->nparents = i - 1;
 587                 len = sane_truncate_line(ecbdata, line, len);
 588                 emit_line(ecbdata->file,
 589                           diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO),
 590                           reset, line, len);
 591                 if (line[len-1] != '\n')
 592                         putc('\n', ecbdata->file);
 593                 return;
 594         }
 595
 596         if (len < ecbdata->nparents) {
 597                 emit_line(ecbdata->file, reset, reset, line, len);
 598                 return;
 599         }
 600
 601         color = DIFF_PLAIN;
 602         if (ecbdata->diff_words && ecbdata->nparents != 1)
 603                 /* fall back to normal diff */
 604                 free_diff_words_data(ecbdata);
 605         if (ecbdata->diff_words) {
 606                 if (line[0] == '-') {
 607                         diff_words_append(line, len,
 608                                           &ecbdata->diff_words->minus);
 609                         return;
 610                 } else if (line[0] == '+') {
 611                         diff_words_append(line, len,
 612                                           &ecbdata->diff_words->plus);
 613                         return;
 614                 }
 615                 if (ecbdata->diff_words->minus.text.size ||
 616                     ecbdata->diff_words->plus.text.size)
 617                         diff_words_show(ecbdata->diff_words);
 618                 line++;
 619                 len--;
 620                 emit_line(ecbdata->file, plain, reset, line, len);
 621                 return;
 622         }
 623         for (i = 0; i < ecbdata->nparents && len; i++) {
 624                 if (line[i] == '-')
 625                         color = DIFF_FILE_OLD;
 626                 else if (line[i] == '+')
 627                         color = DIFF_FILE_NEW;
 628         }
 629
 630         if (color != DIFF_FILE_NEW) {
 631                 emit_line(ecbdata->file,
 632                           diff_get_color(ecbdata->color_diff, color),
 633                           reset, line, len);
 634                 return;
 635         }
 636         emit_add_line(reset, ecbdata, line, len);
 637 }
 638
 639 static char *pprint_rename(const char *a, const char *b)
 640 {
 641         const char *old = a;
 642         const char *new = b;
 643         struct strbuf name;
 644         int pfx_length, sfx_length;
 645         int len_a = strlen(a);
 646         int len_b = strlen(b);
 647         int a_midlen, b_midlen;
 648         int qlen_a = quote_c_style(a, NULL, NULL, 0);
 649         int qlen_b = quote_c_style(b, NULL, NULL, 0);
 650
 651         strbuf_init(&name, 0);
 652         if (qlen_a || qlen_b) {
 653                 quote_c_style(a, &name, NULL, 0);
 654                 strbuf_addstr(&name, " => ");
 655                 quote_c_style(b, &name, NULL, 0);
 656                 return strbuf_detach(&name, NULL);
 657         }
 658
 659         /* Find common prefix */
 660         pfx_length = 0;
 661         while (*old && *new && *old == *new) {
 662                 if (*old == '/')
 663                         pfx_length = old - a + 1;
 664                 old++;
 665                 new++;
 666         }
 667
 668         /* Find common suffix */
 669         old = a + len_a;
 670         new = b + len_b;
 671         sfx_length = 0;
 672         while (a <= old && b <= new && *old == *new) {
 673                 if (*old == '/')
 674                         sfx_length = len_a - (old - a);
 675                 old--;
 676                 new--;
 677         }
 678
 679         /*
 680          * pfx{mid-a => mid-b}sfx
 681          * {pfx-a => pfx-b}sfx
 682          * pfx{sfx-a => sfx-b}
 683          * name-a => name-b
 684          */
 685         a_midlen = len_a - pfx_length - sfx_length;
 686         b_midlen = len_b - pfx_length - sfx_length;
 687         if (a_midlen < 0)
 688                 a_midlen = 0;
 689         if (b_midlen < 0)
 690                 b_midlen = 0;
 691
 692         strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
 693         if (pfx_length + sfx_length) {
 694                 strbuf_add(&name, a, pfx_length);
 695                 strbuf_addch(&name, '{');
 696         }
 697         strbuf_add(&name, a + pfx_length, a_midlen);
 698         strbuf_addstr(&name, " => ");
 699         strbuf_add(&name, b + pfx_length, b_midlen);
 700         if (pfx_length + sfx_length) {
 701                 strbuf_addch(&name, '}');
 702                 strbuf_add(&name, a + len_a - sfx_length, sfx_length);
 703         }
 704         return strbuf_detach(&name, NULL);
 705 }
 706
 707 struct diffstat_t {
 708         struct xdiff_emit_state xm;
 709
 710         int nr;
 711         int alloc;
 712         struct diffstat_file {
 713                 char *from_name;
 714                 char *name;
 715                 char *print_name;
 716                 unsigned is_unmerged:1;
 717                 unsigned is_binary:1;
 718                 unsigned is_renamed:1;
 719                 unsigned int added, deleted;
 720         } **files;
 721 };
 722
 723 static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
 724                                           const char *name_a,
 725                                           const char *name_b)
 726 {
 727         struct diffstat_file *x;
 728         x = xcalloc(sizeof (*x), 1);
 729         if (diffstat->nr == diffstat->alloc) {
 730                 diffstat->alloc = alloc_nr(diffstat->alloc);
 731                 diffstat->files = xrealloc(diffstat->files,
 732                                 diffstat->alloc * sizeof(x));
 733         }
 734         diffstat->files[diffstat->nr++] = x;
 735         if (name_b) {
 736                 x->from_name = xstrdup(name_a);
 737                 x->name = xstrdup(name_b);
 738                 x->is_renamed = 1;
 739         }
 740         else {
 741                 x->from_name = NULL;
 742                 x->name = xstrdup(name_a);
 743         }
 744         return x;
 745 }
 746
 747 static void diffstat_consume(void *priv, char *line, unsigned long len)
 748 {
 749         struct diffstat_t *diffstat = priv;
 750         struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
 751
 752         if (line[0] == '+')
 753                 x->added++;
 754         else if (line[0] == '-')
 755                 x->deleted++;
 756 }
 757
 758 const char mime_boundary_leader[] = "------------";
 759
 760 static int scale_linear(int it, int width, int max_change)
 761 {
 762         /*
 763          * make sure that at least one '-' is printed if there were deletions,
 764          * and likewise for '+'.
 765          */
 766         if (max_change < 2)
 767                 return it;
 768         return ((it - 1) * (width - 1) + max_change - 1) / (max_change - 1);
 769 }
 770
 771 static void show_name(FILE *file,
 772                       const char *prefix, const char *name, int len,
 773                       const char *reset, const char *set)
 774 {
 775         fprintf(file, " %s%s%-*s%s |", set, prefix, len, name, reset);
 776 }
 777
 778 static void show_graph(FILE *file, char ch, int cnt, const char *set, const char *reset)
 779 {
 780         if (cnt <= 0)
 781                 return;
 782         fprintf(file, "%s", set);
 783         while (cnt--)
 784                 putc(ch, file);
 785         fprintf(file, "%s", reset);
 786 }
 787
 788 static void fill_print_name(struct diffstat_file *file)
 789 {
 790         char *pname;
 791
 792         if (file->print_name)
 793                 return;
 794
 795         if (!file->is_renamed) {
 796                 struct strbuf buf;
 797                 strbuf_init(&buf, 0);
 798                 if (quote_c_style(file->name, &buf, NULL, 0)) {
 799                         pname = strbuf_detach(&buf, NULL);
 800                 } else {
 801                         pname = file->name;
 802                         strbuf_release(&buf);
 803                 }
 804         } else {
 805                 pname = pprint_rename(file->from_name, file->name);
 806         }
 807         file->print_name = pname;
 808 }
 809
 810 static void show_stats(struct diffstat_t* data, struct diff_options *options)
 811 {
 812         int i, len, add, del, total, adds = 0, dels = 0;
 813         int max_change = 0, max_len = 0;
 814         int total_files = data->nr;
 815         int width, name_width;
 816         const char *reset, *set, *add_c, *del_c;
 817
 818         if (data->nr == 0)
 819                 return;
 820
 821         width = options->stat_width ? options->stat_width : 80;
 822         name_width = options->stat_name_width ? options->stat_name_width : 50;
 823
 824         /* Sanity: give at least 5 columns to the graph,
 825          * but leave at least 10 columns for the name.
 826          */
 827         if (width < name_width + 15) {
 828                 if (name_width <= 25)
 829                         width = name_width + 15;
 830                 else
 831                         name_width = width - 15;
 832         }
 833
 834         /* Find the longest filename and max number of changes */
 835         reset = diff_get_color_opt(options, DIFF_RESET);
 836         set   = diff_get_color_opt(options, DIFF_PLAIN);
 837         add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
 838         del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
 839
 840         for (i = 0; i < data->nr; i++) {
 841                 struct diffstat_file *file = data->files[i];
 842                 int change = file->added + file->deleted;
 843                 fill_print_name(file);
 844                 len = strlen(file->print_name);
 845                 if (max_len < len)
 846                         max_len = len;
 847
 848                 if (file->is_binary || file->is_unmerged)
 849                         continue;
 850                 if (max_change < change)
 851                         max_change = change;
 852         }
 853
 854         /* Compute the width of the graph part;
 855          * 10 is for one blank at the beginning of the line plus
 856          * " | count " between the name and the graph.
 857          *
 858          * From here on, name_width is the width of the name area,
 859          * and width is the width of the graph area.
 860          */
 861         name_width = (name_width < max_len) ? name_width : max_len;
 862         if (width < (name_width + 10) + max_change)
 863                 width = width - (name_width + 10);
 864         else
 865                 width = max_change;
 866
 867         for (i = 0; i < data->nr; i++) {
 868                 const char *prefix = "";
 869                 char *name = data->files[i]->print_name;
 870                 int added = data->files[i]->added;
 871                 int deleted = data->files[i]->deleted;
 872                 int name_len;
 873
 874                 /*
 875                  * "scale" the filename
 876                  */
 877                 len = name_width;
 878                 name_len = strlen(name);
 879                 if (name_width < name_len) {
 880                         char *slash;
 881                         prefix = "...";
 882                         len -= 3;
 883                         name += name_len - len;
 884                         slash = strchr(name, '/');
 885                         if (slash)
 886                                 name = slash;
 887                 }
 888
 889                 if (data->files[i]->is_binary) {
 890                         show_name(options->file, prefix, name, len, reset, set);
 891                         fprintf(options->file, "  Bin ");
 892                         fprintf(options->file, "%s%d%s", del_c, deleted, reset);
 893                         fprintf(options->file, " -> ");
 894                         fprintf(options->file, "%s%d%s", add_c, added, reset);
 895                         fprintf(options->file, " bytes");
 896                         fprintf(options->file, "\n");
 897                         continue;
 898                 }
 899                 else if (data->files[i]->is_unmerged) {
 900                         show_name(options->file, prefix, name, len, reset, set);
 901                         fprintf(options->file, "  Unmerged\n");
 902                         continue;
 903                 }
 904                 else if (!data->files[i]->is_renamed &&
 905                          (added + deleted == 0)) {
 906                         total_files--;
 907                         continue;
 908                 }
 909
 910                 /*
 911                  * scale the add/delete
 912                  */
 913                 add = added;
 914                 del = deleted;
 915                 total = add + del;
 916                 adds += add;
 917                 dels += del;
 918
 919                 if (width <= max_change) {
 920                         add = scale_linear(add, width, max_change);
 921                         del = scale_linear(del, width, max_change);
 922                         total = add + del;
 923                 }
 924                 show_name(options->file, prefix, name, len, reset, set);
 925                 fprintf(options->file, "%5d ", added + deleted);
 926                 show_graph(options->file, '+', add, add_c, reset);
 927                 show_graph(options->file, '-', del, del_c, reset);
 928                 fprintf(options->file, "\n");
 929         }
 930         fprintf(options->file,
 931                "%s %d files changed, %d insertions(+), %d deletions(-)%s\n",
 932                set, total_files, adds, dels, reset);
 933 }
 934
 935 static void show_shortstats(struct diffstat_t* data, struct diff_options *options)
 936 {
 937         int i, adds = 0, dels = 0, total_files = data->nr;
 938
 939         if (data->nr == 0)
 940                 return;
 941
 942         for (i = 0; i < data->nr; i++) {
 943                 if (!data->files[i]->is_binary &&
 944                     !data->files[i]->is_unmerged) {
 945                         int added = data->files[i]->added;
 946                         int deleted= data->files[i]->deleted;
 947                         if (!data->files[i]->is_renamed &&
 948                             (added + deleted == 0)) {
 949                                 total_files--;
 950                         } else {
 951                                 adds += added;
 952                                 dels += deleted;
 953                         }
 954                 }
 955         }
 956         fprintf(options->file, " %d files changed, %d insertions(+), %d deletions(-)\n",
 957                total_files, adds, dels);
 958 }
 959
 960 static void show_numstat(struct diffstat_t* data, struct diff_options *options)
 961 {
 962         int i;
 963
 964         if (data->nr == 0)
 965                 return;
 966
 967         for (i = 0; i < data->nr; i++) {
 968                 struct diffstat_file *file = data->files[i];
 969
 970                 if (file->is_binary)
 971                         fprintf(options->file, "-\t-\t");
 972                 else
 973                         fprintf(options->file,
 974                                 "%d\t%d\t", file->added, file->deleted);
 975                 if (options->line_termination) {
 976                         fill_print_name(file);
 977                         if (!file->is_renamed)
 978                                 write_name_quoted(file->name, options->file,
 979                                                   options->line_termination);
 980                         else {
 981                                 fputs(file->print_name, options->file);
 982                                 putc(options->line_termination, options->file);
 983                         }
 984                 } else {
 985                         if (file->is_renamed) {
 986                                 putc('\0', options->file);
 987                                 write_name_quoted(file->from_name, options->file, '\0');
 988                         }
 989                         write_name_quoted(file->name, options->file, '\0');
 990                 }
 991         }
 992 }
 993
 994 struct dirstat_file {
 995         const char *name;
 996         unsigned long changed;
 997 };
 998
 999 struct dirstat_dir {
1000         struct dirstat_file *files;
1001         int alloc, nr, percent, cumulative;
1002 };
1003
1004 static long gather_dirstat(FILE *file, struct dirstat_dir *dir, unsigned long changed, const char *base, int baselen)
1005 {
1006         unsigned long this_dir = 0;
1007         unsigned int sources = 0;
1008
1009         while (dir->nr) {
1010                 struct dirstat_file *f = dir->files;
1011                 int namelen = strlen(f->name);
1012                 unsigned long this;
1013                 char *slash;
1014
1015                 if (namelen < baselen)
1016                         break;
1017                 if (memcmp(f->name, base, baselen))
1018                         break;
1019                 slash = strchr(f->name + baselen, '/');
1020                 if (slash) {
1021                         int newbaselen = slash + 1 - f->name;
1022                         this = gather_dirstat(file, dir, changed, f->name, newbaselen);
1023                         sources++;
1024                 } else {
1025                         this = f->changed;
1026                         dir->files++;
1027                         dir->nr--;
1028                         sources += 2;
1029                 }
1030                 this_dir += this;
1031         }
1032
1033         /*
1034          * We don't report dirstat's for
1035          *  - the top level
1036          *  - or cases where everything came from a single directory
1037          *    under this directory (sources == 1).
1038          */
1039         if (baselen && sources != 1) {
1040                 int permille = this_dir * 1000 / changed;
1041                 if (permille) {
1042                         int percent = permille / 10;
1043                         if (percent >= dir->percent) {
1044                                 fprintf(file, "%4d.%01d%% %.*s\n", percent, permille % 10, baselen, base);
1045                                 if (!dir->cumulative)
1046                                         return 0;
1047                         }
1048                 }
1049         }
1050         return this_dir;
1051 }
1052
1053 static void show_dirstat(struct diff_options *options)
1054 {
1055         int i;
1056         unsigned long changed;
1057         struct dirstat_dir dir;
1058         struct diff_queue_struct *q = &diff_queued_diff;
1059
1060         dir.files = NULL;
1061         dir.alloc = 0;
1062         dir.nr = 0;
1063         dir.percent = options->dirstat_percent;
1064         dir.cumulative = options->output_format & DIFF_FORMAT_CUMULATIVE;
1065
1066         changed = 0;
1067         for (i = 0; i < q->nr; i++) {
1068                 struct diff_filepair *p = q->queue[i];
1069                 const char *name;
1070                 unsigned long copied, added, damage;
1071
1072                 name = p->one->path ? p->one->path : p->two->path;
1073
1074                 if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
1075                         diff_populate_filespec(p->one, 0);
1076                         diff_populate_filespec(p->two, 0);
1077                         diffcore_count_changes(p->one, p->two, NULL, NULL, 0,
1078                                                &copied, &added);
1079                         diff_free_filespec_data(p->one);
1080                         diff_free_filespec_data(p->two);
1081                 } else if (DIFF_FILE_VALID(p->one)) {
1082                         diff_populate_filespec(p->one, 1);
1083                         copied = added = 0;
1084                         diff_free_filespec_data(p->one);
1085                 } else if (DIFF_FILE_VALID(p->two)) {
1086                         diff_populate_filespec(p->two, 1);
1087                         copied = 0;
1088                         added = p->two->size;
1089                         diff_free_filespec_data(p->two);
1090                 } else
1091                         continue;
1092
1093                 /*
1094                  * Original minus copied is the removed material,
1095                  * added is the new material.  They are both damages
1096                  * made to the preimage.
1097                  */
1098                 damage = (p->one->size - copied) + added;
1099
1100                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
1101                 dir.files[dir.nr].name = name;
1102                 dir.files[dir.nr].changed = damage;
1103                 changed += damage;
1104                 dir.nr++;
1105         }
1106
1107         /* This can happen even with many files, if everything was renames */
1108         if (!changed)
1109                 return;
1110
1111         /* Show all directories with more than x% of the changes */
1112         gather_dirstat(options->file, &dir, changed, "", 0);
1113 }
1114
1115 static void free_diffstat_info(struct diffstat_t *diffstat)
1116 {
1117         int i;
1118         for (i = 0; i < diffstat->nr; i++) {
1119                 struct diffstat_file *f = diffstat->files[i];
1120                 if (f->name != f->print_name)
1121                         free(f->print_name);
1122                 free(f->name);
1123                 free(f->from_name);
1124                 free(f);
1125         }
1126         free(diffstat->files);
1127 }
1128
1129 struct checkdiff_t {
1130         struct xdiff_emit_state xm;
1131         const char *filename;
1132         int lineno, color_diff;
1133         unsigned ws_rule;
1134         unsigned status;
1135         FILE *file;
1136 };
1137
1138 static void checkdiff_consume(void *priv, char *line, unsigned long len)
1139 {
1140         struct checkdiff_t *data = priv;
1141         const char *ws = diff_get_color(data->color_diff, DIFF_WHITESPACE);
1142         const char *reset = diff_get_color(data->color_diff, DIFF_RESET);
1143         const char *set = diff_get_color(data->color_diff, DIFF_FILE_NEW);
1144         char *err;
1145
1146         if (line[0] == '+') {
1147                 data->lineno++;
1148                 data->status = check_and_emit_line(line + 1, len - 1,
1149                     data->ws_rule, NULL, NULL, NULL, NULL);
1150                 if (!data->status)
1151                         return;
1152                 err = whitespace_error_string(data->status);
1153                 fprintf(data->file, "%s:%d: %s.\n", data->filename, data->lineno, err);
1154                 free(err);
1155                 emit_line(data->file, set, reset, line, 1);
1156                 (void)check_and_emit_line(line + 1, len - 1, data->ws_rule,
1157                     data->file, set, reset, ws);
1158         } else if (line[0] == ' ')
1159                 data->lineno++;
1160         else if (line[0] == '@') {
1161                 char *plus = strchr(line, '+');
1162                 if (plus)
1163                         data->lineno = strtol(plus, NULL, 10) - 1;
1164                 else
1165                         die("invalid diff");
1166         }
1167 }
1168
1169 static unsigned char *deflate_it(char *data,
1170                                  unsigned long size,
1171                                  unsigned long *result_size)
1172 {
1173         int bound;
1174         unsigned char *deflated;
1175         z_stream stream;
1176
1177         memset(&stream, 0, sizeof(stream));
1178         deflateInit(&stream, zlib_compression_level);
1179         bound = deflateBound(&stream, size);
1180         deflated = xmalloc(bound);
1181         stream.next_out = deflated;
1182         stream.avail_out = bound;
1183
1184         stream.next_in = (unsigned char *)data;
1185         stream.avail_in = size;
1186         while (deflate(&stream, Z_FINISH) == Z_OK)
1187                 ; /* nothing */
1188         deflateEnd(&stream);
1189         *result_size = stream.total_out;
1190         return deflated;
1191 }
1192
1193 static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two)
1194 {
1195         void *cp;
1196         void *delta;
1197         void *deflated;
1198         void *data;
1199         unsigned long orig_size;
1200         unsigned long delta_size;
1201         unsigned long deflate_size;
1202         unsigned long data_size;
1203
1204         /* We could do deflated delta, or we could do just deflated two,
1205          * whichever is smaller.
1206          */
1207         delta = NULL;
1208         deflated = deflate_it(two->ptr, two->size, &deflate_size);
1209         if (one->size && two->size) {
1210                 delta = diff_delta(one->ptr, one->size,
1211                                    two->ptr, two->size,
1212                                    &delta_size, deflate_size);
1213                 if (delta) {
1214                         void *to_free = delta;
1215                         orig_size = delta_size;
1216                         delta = deflate_it(delta, delta_size, &delta_size);
1217                         free(to_free);
1218                 }
1219         }
1220
1221         if (delta && delta_size < deflate_size) {
1222                 fprintf(file, "delta %lu\n", orig_size);
1223                 free(deflated);
1224                 data = delta;
1225                 data_size = delta_size;
1226         }
1227         else {
1228                 fprintf(file, "literal %lu\n", two->size);
1229                 free(delta);
1230                 data = deflated;
1231                 data_size = deflate_size;
1232         }
1233
1234         /* emit data encoded in base85 */
1235         cp = data;
1236         while (data_size) {
1237                 int bytes = (52 < data_size) ? 52 : data_size;
1238                 char line[70];
1239                 data_size -= bytes;
1240                 if (bytes <= 26)
1241                         line[0] = bytes + 'A' - 1;
1242                 else
1243                         line[0] = bytes - 26 + 'a' - 1;
1244                 encode_85(line + 1, cp, bytes);
1245                 cp = (char *) cp + bytes;
1246                 fputs(line, file);
1247                 fputc('\n', file);
1248         }
1249         fprintf(file, "\n");
1250         free(data);
1251 }
1252
1253 static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two)
1254 {
1255         fprintf(file, "GIT binary patch\n");
1256         emit_binary_diff_body(file, one, two);
1257         emit_binary_diff_body(file, two, one);
1258 }
1259
1260 static void setup_diff_attr_check(struct git_attr_check *check)
1261 {
1262         static struct git_attr *attr_diff;
1263
1264         if (!attr_diff) {
1265                 attr_diff = git_attr("diff", 4);
1266         }
1267         check[0].attr = attr_diff;
1268 }
1269
1270 static void diff_filespec_check_attr(struct diff_filespec *one)
1271 {
1272         struct git_attr_check attr_diff_check;
1273         int check_from_data = 0;
1274
1275         if (one->checked_attr)
1276                 return;
1277
1278         setup_diff_attr_check(&attr_diff_check);
1279         one->is_binary = 0;
1280         one->funcname_pattern_ident = NULL;
1281
1282         if (!git_checkattr(one->path, 1, &attr_diff_check)) {
1283                 const char *value;
1284
1285                 /* binaryness */
1286                 value = attr_diff_check.value;
1287                 if (ATTR_TRUE(value))
1288                         ;
1289                 else if (ATTR_FALSE(value))
1290                         one->is_binary = 1;
1291                 else
1292                         check_from_data = 1;
1293
1294                 /* funcname pattern ident */
1295                 if (ATTR_TRUE(value) || ATTR_FALSE(value) || ATTR_UNSET(value))
1296                         ;
1297                 else
1298                         one->funcname_pattern_ident = value;
1299         }
1300
1301         if (check_from_data) {
1302                 if (!one->data && DIFF_FILE_VALID(one))
1303                         diff_populate_filespec(one, 0);
1304
1305                 if (one->data)
1306                         one->is_binary = buffer_is_binary(one->data, one->size);
1307         }
1308 }
1309
1310 int diff_filespec_is_binary(struct diff_filespec *one)
1311 {
1312         diff_filespec_check_attr(one);
1313         return one->is_binary;
1314 }
1315
1316 static const char *funcname_pattern(const char *ident)
1317 {
1318         struct funcname_pattern *pp;
1319
1320         for (pp = funcname_pattern_list; pp; pp = pp->next)
1321                 if (!strcmp(ident, pp->name))
1322                         return pp->pattern;
1323         return NULL;
1324 }
1325
1326 static struct builtin_funcname_pattern {
1327         const char *name;
1328         const char *pattern;
1329 } builtin_funcname_pattern[] = {
1330         { "java", "!^[  ]*\\(catch\\|do\\|for\\|if\\|instanceof\\|"
1331                         "new\\|return\\|switch\\|throw\\|while\\)\n"
1332                         "^[     ]*\\(\\([       ]*"
1333                         "[A-Za-z_][A-Za-z_0-9]*\\)\\{2,\\}"
1334                         "[      ]*([^;]*\\)$" },
1335         { "tex", "^\\(\\\\\\(sub\\)*section{.*\\)$" },
1336 };
1337
1338 static const char *diff_funcname_pattern(struct diff_filespec *one)
1339 {
1340         const char *ident, *pattern;
1341         int i;
1342
1343         diff_filespec_check_attr(one);
1344         ident = one->funcname_pattern_ident;
1345
1346         if (!ident)
1347                 /*
1348                  * If the config file has "funcname.default" defined, that
1349                  * regexp is used; otherwise NULL is returned and xemit uses
1350                  * the built-in default.
1351                  */
1352                 return funcname_pattern("default");
1353
1354         /* Look up custom "funcname.$ident" regexp from config. */
1355         pattern = funcname_pattern(ident);
1356         if (pattern)
1357                 return pattern;
1358
1359         /*
1360          * And define built-in fallback patterns here.  Note that
1361          * these can be overridden by the user's config settings.
1362          */
1363         for (i = 0; i < ARRAY_SIZE(builtin_funcname_pattern); i++)
1364                 if (!strcmp(ident, builtin_funcname_pattern[i].name))
1365                         return builtin_funcname_pattern[i].pattern;
1366
1367         return NULL;
1368 }
1369
1370 static void builtin_diff(const char *name_a,
1371                          const char *name_b,
1372                          struct diff_filespec *one,
1373                          struct diff_filespec *two,
1374                          const char *xfrm_msg,
1375                          struct diff_options *o,
1376                          int complete_rewrite)
1377 {
1378         mmfile_t mf1, mf2;
1379         const char *lbl[2];
1380         char *a_one, *b_two;
1381         const char *set = diff_get_color_opt(o, DIFF_METAINFO);
1382         const char *reset = diff_get_color_opt(o, DIFF_RESET);
1383
1384         a_one = quote_two(o->a_prefix, name_a + (*name_a == '/'));
1385         b_two = quote_two(o->b_prefix, name_b + (*name_b == '/'));
1386         lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
1387         lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
1388         fprintf(o->file, "%sdiff --git %s %s%s\n", set, a_one, b_two, reset);
1389         if (lbl[0][0] == '/') {
1390                 /* /dev/null */
1391                 fprintf(o->file, "%snew file mode %06o%s\n", set, two->mode, reset);
1392                 if (xfrm_msg && xfrm_msg[0])
1393                         fprintf(o->file, "%s%s%s\n", set, xfrm_msg, reset);
1394         }
1395         else if (lbl[1][0] == '/') {
1396                 fprintf(o->file, "%sdeleted file mode %06o%s\n", set, one->mode, reset);
1397                 if (xfrm_msg && xfrm_msg[0])
1398                         fprintf(o->file, "%s%s%s\n", set, xfrm_msg, reset);
1399         }
1400         else {
1401                 if (one->mode != two->mode) {
1402                         fprintf(o->file, "%sold mode %06o%s\n", set, one->mode, reset);
1403                         fprintf(o->file, "%snew mode %06o%s\n", set, two->mode, reset);
1404                 }
1405                 if (xfrm_msg && xfrm_msg[0])
1406                         fprintf(o->file, "%s%s%s\n", set, xfrm_msg, reset);
1407                 /*
1408                  * we do not run diff between different kind
1409                  * of objects.
1410                  */
1411                 if ((one->mode ^ two->mode) & S_IFMT)
1412                         goto free_ab_and_return;
1413                 if (complete_rewrite) {
1414                         emit_rewrite_diff(name_a, name_b, one, two, o);
1415                         o->found_changes = 1;
1416                         goto free_ab_and_return;
1417                 }
1418         }
1419
1420         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
1421                 die("unable to read files to diff");
1422
1423         if (!DIFF_OPT_TST(o, TEXT) &&
1424             (diff_filespec_is_binary(one) || diff_filespec_is_binary(two))) {
1425                 /* Quite common confusing case */
1426                 if (mf1.size == mf2.size &&
1427                     !memcmp(mf1.ptr, mf2.ptr, mf1.size))
1428                         goto free_ab_and_return;
1429                 if (DIFF_OPT_TST(o, BINARY))
1430                         emit_binary_diff(o->file, &mf1, &mf2);
1431                 else
1432                         fprintf(o->file, "Binary files %s and %s differ\n",
1433                                 lbl[0], lbl[1]);
1434                 o->found_changes = 1;
1435         }
1436         else {
1437                 /* Crazy xdl interfaces.. */
1438                 const char *diffopts = getenv("GIT_DIFF_OPTS");
1439                 xpparam_t xpp;
1440                 xdemitconf_t xecfg;
1441                 xdemitcb_t ecb;
1442                 struct emit_callback ecbdata;
1443                 const char *funcname_pattern;
1444
1445                 funcname_pattern = diff_funcname_pattern(one);
1446                 if (!funcname_pattern)
1447                         funcname_pattern = diff_funcname_pattern(two);
1448
1449                 memset(&xecfg, 0, sizeof(xecfg));
1450                 memset(&ecbdata, 0, sizeof(ecbdata));
1451                 ecbdata.label_path = lbl;
1452                 ecbdata.color_diff = DIFF_OPT_TST(o, COLOR_DIFF);
1453                 ecbdata.found_changesp = &o->found_changes;
1454                 ecbdata.ws_rule = whitespace_rule(name_b ? name_b : name_a);
1455                 ecbdata.file = o->file;
1456                 xpp.flags = XDF_NEED_MINIMAL | o->xdl_opts;
1457                 xecfg.ctxlen = o->context;
1458                 xecfg.flags = XDL_EMIT_FUNCNAMES;
1459                 if (funcname_pattern)
1460                         xdiff_set_find_func(&xecfg, funcname_pattern);
1461                 if (!diffopts)
1462                         ;
1463                 else if (!prefixcmp(diffopts, "--unified="))
1464                         xecfg.ctxlen = strtoul(diffopts + 10, NULL, 10);
1465                 else if (!prefixcmp(diffopts, "-u"))
1466                         xecfg.ctxlen = strtoul(diffopts + 2, NULL, 10);
1467                 ecb.outf = xdiff_outf;
1468                 ecb.priv = &ecbdata;
1469                 ecbdata.xm.consume = fn_out_consume;
1470                 if (DIFF_OPT_TST(o, COLOR_DIFF_WORDS)) {
1471                         ecbdata.diff_words =
1472                                 xcalloc(1, sizeof(struct diff_words_data));
1473                         ecbdata.diff_words->file = o->file;
1474                 }
1475                 xdi_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
1476                 if (DIFF_OPT_TST(o, COLOR_DIFF_WORDS))
1477                         free_diff_words_data(&ecbdata);
1478         }
1479
1480  free_ab_and_return:
1481         diff_free_filespec_data(one);
1482         diff_free_filespec_data(two);
1483         free(a_one);
1484         free(b_two);
1485         return;
1486 }
1487
1488 static void builtin_diffstat(const char *name_a, const char *name_b,
1489                              struct diff_filespec *one,
1490                              struct diff_filespec *two,
1491                              struct diffstat_t *diffstat,
1492                              struct diff_options *o,
1493                              int complete_rewrite)
1494 {
1495         mmfile_t mf1, mf2;
1496         struct diffstat_file *data;
1497
1498         data = diffstat_add(diffstat, name_a, name_b);
1499
1500         if (!one || !two) {
1501                 data->is_unmerged = 1;
1502                 return;
1503         }
1504         if (complete_rewrite) {
1505                 diff_populate_filespec(one, 0);
1506                 diff_populate_filespec(two, 0);
1507                 data->deleted = count_lines(one->data, one->size);
1508                 data->added = count_lines(two->data, two->size);
1509                 goto free_and_return;
1510         }
1511         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
1512                 die("unable to read files to diff");
1513
1514         if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
1515                 data->is_binary = 1;
1516                 data->added = mf2.size;
1517                 data->deleted = mf1.size;
1518         } else {
1519                 /* Crazy xdl interfaces.. */
1520                 xpparam_t xpp;
1521                 xdemitconf_t xecfg;
1522                 xdemitcb_t ecb;
1523
1524                 memset(&xecfg, 0, sizeof(xecfg));
1525                 xpp.flags = XDF_NEED_MINIMAL | o->xdl_opts;
1526                 ecb.outf = xdiff_outf;
1527                 ecb.priv = diffstat;
1528                 xdi_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
1529         }
1530
1531  free_and_return:
1532         diff_free_filespec_data(one);
1533         diff_free_filespec_data(two);
1534 }
1535
1536 static void builtin_checkdiff(const char *name_a, const char *name_b,
1537                               const char *attr_path,
1538                              struct diff_filespec *one,
1539                              struct diff_filespec *two, struct diff_options *o)
1540 {
1541         mmfile_t mf1, mf2;
1542         struct checkdiff_t data;
1543
1544         if (!two)
1545                 return;
1546
1547         memset(&data, 0, sizeof(data));
1548         data.xm.consume = checkdiff_consume;
1549         data.filename = name_b ? name_b : name_a;
1550         data.lineno = 0;
1551         data.color_diff = DIFF_OPT_TST(o, COLOR_DIFF);
1552         data.ws_rule = whitespace_rule(attr_path);
1553         data.file = o->file;
1554
1555         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
1556                 die("unable to read files to diff");
1557
1558         if (diff_filespec_is_binary(two))
1559                 goto free_and_return;
1560         else {
1561                 /* Crazy xdl interfaces.. */
1562                 xpparam_t xpp;
1563                 xdemitconf_t xecfg;
1564                 xdemitcb_t ecb;
1565
1566                 memset(&xecfg, 0, sizeof(xecfg));
1567                 xpp.flags = XDF_NEED_MINIMAL;
1568                 ecb.outf = xdiff_outf;
1569                 ecb.priv = &data;
1570                 xdi_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
1571         }
1572  free_and_return:
1573         diff_free_filespec_data(one);
1574         diff_free_filespec_data(two);
1575         if (data.status)
1576                 DIFF_OPT_SET(o, CHECK_FAILED);
1577 }
1578
1579 struct diff_filespec *alloc_filespec(const char *path)
1580 {
1581         int namelen = strlen(path);
1582         struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
1583
1584         memset(spec, 0, sizeof(*spec));
1585         spec->path = (char *)(spec + 1);
1586         memcpy(spec->path, path, namelen+1);
1587         spec->count = 1;
1588         return spec;
1589 }
1590
1591 void free_filespec(struct diff_filespec *spec)
1592 {
1593         if (!--spec->count) {
1594                 diff_free_filespec_data(spec);
1595                 free(spec);
1596         }
1597 }
1598
1599 void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
1600                    unsigned short mode)
1601 {
1602         if (mode) {
1603                 spec->mode = canon_mode(mode);
1604                 hashcpy(spec->sha1, sha1);
1605                 spec->sha1_valid = !is_null_sha1(sha1);
1606         }
1607 }
1608
1609 /*
1610  * Given a name and sha1 pair, if the index tells us the file in
1611  * the work tree has that object contents, return true, so that
1612  * prepare_temp_file() does not have to inflate and extract.
1613  */
1614 static int reuse_worktree_file(const char *name, const unsigned char *sha1, int want_file)
1615 {
1616         struct cache_entry *ce;
1617         struct stat st;
1618         int pos, len;
1619
1620         /* We do not read the cache ourselves here, because the
1621          * benchmark with my previous version that always reads cache
1622          * shows that it makes things worse for diff-tree comparing
1623          * two linux-2.6 kernel trees in an already checked out work
1624          * tree.  This is because most diff-tree comparisons deal with
1625          * only a small number of files, while reading the cache is
1626          * expensive for a large project, and its cost outweighs the
1627          * savings we get by not inflating the object to a temporary
1628          * file.  Practically, this code only helps when we are used
1629          * by diff-cache --cached, which does read the cache before
1630          * calling us.
1631          */
1632         if (!active_cache)
1633                 return 0;
1634
1635         /* We want to avoid the working directory if our caller
1636          * doesn't need the data in a normal file, this system
1637          * is rather slow with its stat/open/mmap/close syscalls,
1638          * and the object is contained in a pack file.  The pack
1639          * is probably already open and will be faster to obtain
1640          * the data through than the working directory.  Loose
1641          * objects however would tend to be slower as they need
1642          * to be individually opened and inflated.
1643          */
1644         if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(sha1, NULL))
1645                 return 0;
1646
1647         len = strlen(name);
1648         pos = cache_name_pos(name, len);
1649         if (pos < 0)
1650                 return 0;
1651         ce = active_cache[pos];
1652
1653         /*
1654          * This is not the sha1 we are looking for, or
1655          * unreusable because it is not a regular file.
1656          */
1657         if (hashcmp(sha1, ce->sha1) || !S_ISREG(ce->ce_mode))
1658                 return 0;
1659
1660         /*
1661          * If ce matches the file in the work tree, we can reuse it.
1662          */
1663         if (ce_uptodate(ce) ||
1664             (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
1665                 return 1;
1666
1667         return 0;
1668 }
1669
1670 static int populate_from_stdin(struct diff_filespec *s)
1671 {
1672         struct strbuf buf;
1673         size_t size = 0;
1674
1675         strbuf_init(&buf, 0);
1676         if (strbuf_read(&buf, 0, 0) < 0)
1677                 return error("error while reading from stdin %s",
1678                                      strerror(errno));
1679
1680         s->should_munmap = 0;
1681         s->data = strbuf_detach(&buf, &size);
1682         s->size = size;
1683         s->should_free = 1;
1684         return 0;
1685 }
1686
1687 static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
1688 {
1689         int len;
1690         char *data = xmalloc(100);
1691         len = snprintf(data, 100,
1692                 "Subproject commit %s\n", sha1_to_hex(s->sha1));
1693         s->data = data;
1694         s->size = len;
1695         s->should_free = 1;
1696         if (size_only) {
1697                 s->data = NULL;
1698                 free(data);
1699         }
1700         return 0;
1701 }
1702
1703 /*
1704  * While doing rename detection and pickaxe operation, we may need to
1705  * grab the data for the blob (or file) for our own in-core comparison.
1706  * diff_filespec has data and size fields for this purpose.
1707  */
1708 int diff_populate_filespec(struct diff_filespec *s, int size_only)
1709 {
1710         int err = 0;
1711         if (!DIFF_FILE_VALID(s))
1712                 die("internal error: asking to populate invalid file.");
1713         if (S_ISDIR(s->mode))
1714                 return -1;
1715
1716         if (s->data)
1717                 return 0;
1718
1719         if (size_only && 0 < s->size)
1720                 return 0;
1721
1722         if (S_ISGITLINK(s->mode))
1723                 return diff_populate_gitlink(s, size_only);
1724
1725         if (!s->sha1_valid ||
1726             reuse_worktree_file(s->path, s->sha1, 0)) {
1727                 struct strbuf buf;
1728                 struct stat st;
1729                 int fd;
1730
1731                 if (!strcmp(s->path, "-"))
1732                         return populate_from_stdin(s);
1733
1734                 if (lstat(s->path, &st) < 0) {
1735                         if (errno == ENOENT) {
1736                         err_empty:
1737                                 err = -1;
1738                         empty:
1739                                 s->data = (char *)"";
1740                                 s->size = 0;
1741                                 return err;
1742                         }
1743                 }
1744                 s->size = xsize_t(st.st_size);
1745                 if (!s->size)
1746                         goto empty;
1747                 if (size_only)
1748                         return 0;
1749                 if (S_ISLNK(st.st_mode)) {
1750                         int ret;
1751                         s->data = xmalloc(s->size);
1752                         s->should_free = 1;
1753                         ret = readlink(s->path, s->data, s->size);
1754                         if (ret < 0) {
1755                                 free(s->data);
1756                                 goto err_empty;
1757                         }
1758                         return 0;
1759                 }
1760                 fd = open(s->path, O_RDONLY);
1761                 if (fd < 0)
1762                         goto err_empty;
1763                 s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
1764                 close(fd);
1765                 s->should_munmap = 1;
1766
1767                 /*
1768                  * Convert from working tree format to canonical git format
1769                  */
1770                 strbuf_init(&buf, 0);
1771                 if (convert_to_git(s->path, s->data, s->size, &buf, safe_crlf)) {
1772                         size_t size = 0;
1773                         munmap(s->data, s->size);
1774                         s->should_munmap = 0;
1775                         s->data = strbuf_detach(&buf, &size);
1776                         s->size = size;
1777                         s->should_free = 1;
1778                 }
1779         }
1780         else {
1781                 enum object_type type;
1782                 if (size_only)
1783                         type = sha1_object_info(s->sha1, &s->size);
1784                 else {
1785                         s->data = read_sha1_file(s->sha1, &type, &s->size);
1786                         s->should_free = 1;
1787                 }
1788         }
1789         return 0;
1790 }
1791
1792 void diff_free_filespec_blob(struct diff_filespec *s)
1793 {
1794         if (s->should_free)
1795                 free(s->data);
1796         else if (s->should_munmap)
1797                 munmap(s->data, s->size);
1798
1799         if (s->should_free || s->should_munmap) {
1800                 s->should_free = s->should_munmap = 0;
1801                 s->data = NULL;
1802         }
1803 }
1804
1805 void diff_free_filespec_data(struct diff_filespec *s)
1806 {
1807         diff_free_filespec_blob(s);
1808         free(s->cnt_data);
1809         s->cnt_data = NULL;
1810 }
1811
1812 static void prep_temp_blob(struct diff_tempfile *temp,
1813                            void *blob,
1814                            unsigned long size,
1815                            const unsigned char *sha1,
1816                            int mode)
1817 {
1818         int fd;
1819
1820         fd = git_mkstemp(temp->tmp_path, PATH_MAX, ".diff_XXXXXX");
1821         if (fd < 0)
1822                 die("unable to create temp-file: %s", strerror(errno));
1823         if (write_in_full(fd, blob, size) != size)
1824                 die("unable to write temp-file");
1825         close(fd);
1826         temp->name = temp->tmp_path;
1827         strcpy(temp->hex, sha1_to_hex(sha1));
1828         temp->hex[40] = 0;
1829         sprintf(temp->mode, "%06o", mode);
1830 }
1831
1832 static void prepare_temp_file(const char *name,
1833                               struct diff_tempfile *temp,
1834                               struct diff_filespec *one)
1835 {
1836         if (!DIFF_FILE_VALID(one)) {
1837         not_a_valid_file:
1838                 /* A '-' entry produces this for file-2, and
1839                  * a '+' entry produces this for file-1.
1840                  */
1841                 temp->name = "/dev/null";
1842                 strcpy(temp->hex, ".");
1843                 strcpy(temp->mode, ".");
1844                 return;
1845         }
1846
1847         if (!one->sha1_valid ||
1848             reuse_worktree_file(name, one->sha1, 1)) {
1849                 struct stat st;
1850                 if (lstat(name, &st) < 0) {
1851                         if (errno == ENOENT)
1852                                 goto not_a_valid_file;
1853                         die("stat(%s): %s", name, strerror(errno));
1854                 }
1855                 if (S_ISLNK(st.st_mode)) {
1856                         int ret;
1857                         char buf[PATH_MAX + 1]; /* ought to be SYMLINK_MAX */
1858                         size_t sz = xsize_t(st.st_size);
1859                         if (sizeof(buf) <= st.st_size)
1860                                 die("symlink too long: %s", name);
1861                         ret = readlink(name, buf, sz);
1862                         if (ret < 0)
1863                                 die("readlink(%s)", name);
1864                         prep_temp_blob(temp, buf, sz,
1865                                        (one->sha1_valid ?
1866                                         one->sha1 : null_sha1),
1867                                        (one->sha1_valid ?
1868                                         one->mode : S_IFLNK));
1869                 }
1870                 else {
1871                         /* we can borrow from the file in the work tree */
1872                         temp->name = name;
1873                         if (!one->sha1_valid)
1874                                 strcpy(temp->hex, sha1_to_hex(null_sha1));
1875                         else
1876                                 strcpy(temp->hex, sha1_to_hex(one->sha1));
1877                         /* Even though we may sometimes borrow the
1878                          * contents from the work tree, we always want
1879                          * one->mode.  mode is trustworthy even when
1880                          * !(one->sha1_valid), as long as
1881                          * DIFF_FILE_VALID(one).
1882                          */
1883                         sprintf(temp->mode, "%06o", one->mode);
1884                 }
1885                 return;
1886         }
1887         else {
1888                 if (diff_populate_filespec(one, 0))
1889                         die("cannot read data blob for %s", one->path);
1890                 prep_temp_blob(temp, one->data, one->size,
1891                                one->sha1, one->mode);
1892         }
1893 }
1894
1895 static void remove_tempfile(void)
1896 {
1897         int i;
1898
1899         for (i = 0; i < 2; i++)
1900                 if (diff_temp[i].name == diff_temp[i].tmp_path) {
1901                         unlink(diff_temp[i].name);
1902                         diff_temp[i].name = NULL;
1903                 }
1904 }
1905
1906 static void remove_tempfile_on_signal(int signo)
1907 {
1908         remove_tempfile();
1909         signal(SIGINT, SIG_DFL);
1910         raise(signo);
1911 }
1912
1913 /* An external diff command takes:
1914  *
1915  * diff-cmd name infile1 infile1-sha1 infile1-mode \
1916  *               infile2 infile2-sha1 infile2-mode [ rename-to ]
1917  *
1918  */
1919 static void run_external_diff(const char *pgm,
1920                               const char *name,
1921                               const char *other,
1922                               struct diff_filespec *one,
1923                               struct diff_filespec *two,
1924                               const char *xfrm_msg,
1925                               int complete_rewrite)
1926 {
1927         const char *spawn_arg[10];
1928         struct diff_tempfile *temp = diff_temp;
1929         int retval;
1930         static int atexit_asked = 0;
1931         const char *othername;
1932         const char **arg = &spawn_arg[0];
1933
1934         othername = (other? other : name);
1935         if (one && two) {
1936                 prepare_temp_file(name, &temp[0], one);
1937                 prepare_temp_file(othername, &temp[1], two);
1938                 if (! atexit_asked &&
1939                     (temp[0].name == temp[0].tmp_path ||
1940                      temp[1].name == temp[1].tmp_path)) {
1941                         atexit_asked = 1;
1942                         atexit(remove_tempfile);
1943                 }
1944                 signal(SIGINT, remove_tempfile_on_signal);
1945         }
1946
1947         if (one && two) {
1948                 *arg++ = pgm;
1949                 *arg++ = name;
1950                 *arg++ = temp[0].name;
1951                 *arg++ = temp[0].hex;
1952                 *arg++ = temp[0].mode;
1953                 *arg++ = temp[1].name;
1954                 *arg++ = temp[1].hex;
1955                 *arg++ = temp[1].mode;
1956                 if (other) {
1957                         *arg++ = other;
1958                         *arg++ = xfrm_msg;
1959                 }
1960         } else {
1961                 *arg++ = pgm;
1962                 *arg++ = name;
1963         }
1964         *arg = NULL;
1965         fflush(NULL);
1966         retval = run_command_v_opt(spawn_arg, 0);
1967         remove_tempfile();
1968         if (retval) {
1969                 fprintf(stderr, "external diff died, stopping at %s.\n", name);
1970                 exit(1);
1971         }
1972 }
1973
1974 static const char *external_diff_attr(const char *name)
1975 {
1976         struct git_attr_check attr_diff_check;
1977
1978         if (!name)
1979                 return NULL;
1980
1981         setup_diff_attr_check(&attr_diff_check);
1982         if (!git_checkattr(name, 1, &attr_diff_check)) {
1983                 const char *value = attr_diff_check.value;
1984                 if (!ATTR_TRUE(value) &&
1985                     !ATTR_FALSE(value) &&
1986                     !ATTR_UNSET(value)) {
1987                         struct ll_diff_driver *drv;
1988
1989                         for (drv = user_diff; drv; drv = drv->next)
1990                                 if (!strcmp(drv->name, value))
1991                                         return drv->cmd;
1992                 }
1993         }
1994         return NULL;
1995 }
1996
1997 static void run_diff_cmd(const char *pgm,
1998                          const char *name,
1999                          const char *other,
2000                          const char *attr_path,
2001                          struct diff_filespec *one,
2002                          struct diff_filespec *two,
2003                          const char *xfrm_msg,
2004                          struct diff_options *o,
2005                          int complete_rewrite)
2006 {
2007         if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
2008                 pgm = NULL;
2009         else {
2010                 const char *cmd = external_diff_attr(attr_path);
2011                 if (cmd)
2012                         pgm = cmd;
2013         }
2014
2015         if (pgm) {
2016                 run_external_diff(pgm, name, other, one, two, xfrm_msg,
2017                                   complete_rewrite);
2018                 return;
2019         }
2020         if (one && two)
2021                 builtin_diff(name, other ? other : name,
2022                              one, two, xfrm_msg, o, complete_rewrite);
2023         else
2024                 fprintf(o->file, "* Unmerged path %s\n", name);
2025 }
2026
2027 static void diff_fill_sha1_info(struct diff_filespec *one)
2028 {
2029         if (DIFF_FILE_VALID(one)) {
2030                 if (!one->sha1_valid) {
2031                         struct stat st;
2032                         if (!strcmp(one->path, "-")) {
2033                                 hashcpy(one->sha1, null_sha1);
2034                                 return;
2035                         }
2036                         if (lstat(one->path, &st) < 0)
2037                                 die("stat %s", one->path);
2038                         if (index_path(one->sha1, one->path, &st, 0))
2039                                 die("cannot hash %s\n", one->path);
2040                 }
2041         }
2042         else
2043                 hashclr(one->sha1);
2044 }
2045
2046 static int similarity_index(struct diff_filepair *p)
2047 {
2048         return p->score * 100 / MAX_SCORE;
2049 }
2050
2051 static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
2052 {
2053         /* Strip the prefix but do not molest /dev/null and absolute paths */
2054         if (*namep && **namep != '/')
2055                 *namep += prefix_length;
2056         if (*otherp && **otherp != '/')
2057                 *otherp += prefix_length;
2058 }
2059
2060 static void run_diff(struct diff_filepair *p, struct diff_options *o)
2061 {
2062         const char *pgm = external_diff();
2063         struct strbuf msg;
2064         char *xfrm_msg;
2065         struct diff_filespec *one = p->one;
2066         struct diff_filespec *two = p->two;
2067         const char *name;
2068         const char *other;
2069         const char *attr_path;
2070         int complete_rewrite = 0;
2071
2072         name  = p->one->path;
2073         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
2074         attr_path = name;
2075         if (o->prefix_length)
2076                 strip_prefix(o->prefix_length, &name, &other);
2077
2078         if (DIFF_PAIR_UNMERGED(p)) {
2079                 run_diff_cmd(pgm, name, NULL, attr_path,
2080                              NULL, NULL, NULL, o, 0);
2081                 return;
2082         }
2083
2084         diff_fill_sha1_info(one);
2085         diff_fill_sha1_info(two);
2086
2087         strbuf_init(&msg, PATH_MAX * 2 + 300);
2088         switch (p->status) {
2089         case DIFF_STATUS_COPIED:
2090                 strbuf_addf(&msg, "similarity index %d%%", similarity_index(p));
2091                 strbuf_addstr(&msg, "\ncopy from ");
2092                 quote_c_style(name, &msg, NULL, 0);
2093                 strbuf_addstr(&msg, "\ncopy to ");
2094                 quote_c_style(other, &msg, NULL, 0);
2095                 strbuf_addch(&msg, '\n');
2096                 break;
2097         case DIFF_STATUS_RENAMED:
2098                 strbuf_addf(&msg, "similarity index %d%%", similarity_index(p));
2099                 strbuf_addstr(&msg, "\nrename from ");
2100                 quote_c_style(name, &msg, NULL, 0);
2101                 strbuf_addstr(&msg, "\nrename to ");
2102                 quote_c_style(other, &msg, NULL, 0);
2103                 strbuf_addch(&msg, '\n');
2104                 break;
2105         case DIFF_STATUS_MODIFIED:
2106                 if (p->score) {
2107                         strbuf_addf(&msg, "dissimilarity index %d%%\n",
2108                                         similarity_index(p));
2109                         complete_rewrite = 1;
2110                         break;
2111                 }
2112                 /* fallthru */
2113         default:
2114                 /* nothing */
2115                 ;
2116         }
2117
2118         if (hashcmp(one->sha1, two->sha1)) {
2119                 int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
2120
2121                 if (DIFF_OPT_TST(o, BINARY)) {
2122                         mmfile_t mf;
2123                         if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
2124                             (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
2125                                 abbrev = 40;
2126                 }
2127                 strbuf_addf(&msg, "index %.*s..%.*s",
2128                                 abbrev, sha1_to_hex(one->sha1),
2129                                 abbrev, sha1_to_hex(two->sha1));
2130                 if (one->mode == two->mode)
2131                         strbuf_addf(&msg, " %06o", one->mode);
2132                 strbuf_addch(&msg, '\n');
2133         }
2134
2135         if (msg.len)
2136                 strbuf_setlen(&msg, msg.len - 1);
2137         xfrm_msg = msg.len ? msg.buf : NULL;
2138
2139         if (!pgm &&
2140             DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
2141             (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
2142                 /* a filepair that changes between file and symlink
2143                  * needs to be split into deletion and creation.
2144                  */
2145                 struct diff_filespec *null = alloc_filespec(two->path);
2146                 run_diff_cmd(NULL, name, other, attr_path,
2147                              one, null, xfrm_msg, o, 0);
2148                 free(null);
2149                 null = alloc_filespec(one->path);
2150                 run_diff_cmd(NULL, name, other, attr_path,
2151                              null, two, xfrm_msg, o, 0);
2152                 free(null);
2153         }
2154         else
2155                 run_diff_cmd(pgm, name, other, attr_path,
2156                              one, two, xfrm_msg, o, complete_rewrite);
2157
2158         strbuf_release(&msg);
2159 }
2160
2161 static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
2162                          struct diffstat_t *diffstat)
2163 {
2164         const char *name;
2165         const char *other;
2166         int complete_rewrite = 0;
2167
2168         if (DIFF_PAIR_UNMERGED(p)) {
2169                 /* unmerged */
2170                 builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, 0);
2171                 return;
2172         }
2173
2174         name = p->one->path;
2175         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
2176
2177         if (o->prefix_length)
2178                 strip_prefix(o->prefix_length, &name, &other);
2179
2180         diff_fill_sha1_info(p->one);
2181         diff_fill_sha1_info(p->two);
2182
2183         if (p->status == DIFF_STATUS_MODIFIED && p->score)
2184                 complete_rewrite = 1;
2185         builtin_diffstat(name, other, p->one, p->two, diffstat, o, complete_rewrite);
2186 }
2187
2188 static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
2189 {
2190         const char *name;
2191         const char *other;
2192         const char *attr_path;
2193
2194         if (DIFF_PAIR_UNMERGED(p)) {
2195                 /* unmerged */
2196                 return;
2197         }
2198
2199         name = p->one->path;
2200         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
2201         attr_path = other ? other : name;
2202
2203         if (o->prefix_length)
2204                 strip_prefix(o->prefix_length, &name, &other);
2205
2206         diff_fill_sha1_info(p->one);
2207         diff_fill_sha1_info(p->two);
2208
2209         builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
2210 }
2211
2212 void diff_setup(struct diff_options *options)
2213 {
2214         memset(options, 0, sizeof(*options));
2215
2216         options->file = stdout;
2217
2218         options->line_termination = '\n';
2219         options->break_opt = -1;
2220         options->rename_limit = -1;
2221         options->dirstat_percent = 3;
2222         options->context = 3;
2223         options->msg_sep = "";
2224
2225         options->change = diff_change;
2226         options->add_remove = diff_addremove;
2227         if (diff_use_color_default > 0)
2228                 DIFF_OPT_SET(options, COLOR_DIFF);
2229         else
2230                 DIFF_OPT_CLR(options, COLOR_DIFF);
2231         options->detect_rename = diff_detect_rename_default;
2232
2233         options->a_prefix = "a/";
2234         options->b_prefix = "b/";
2235 }
2236
2237 int diff_setup_done(struct diff_options *options)
2238 {
2239         int count = 0;
2240
2241         if (options->output_format & DIFF_FORMAT_NAME)
2242                 count++;
2243         if (options->output_format & DIFF_FORMAT_NAME_STATUS)
2244                 count++;
2245         if (options->output_format & DIFF_FORMAT_CHECKDIFF)
2246                 count++;
2247         if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
2248                 count++;
2249         if (count > 1)
2250                 die("--name-only, --name-status, --check and -s are mutually exclusive");
2251
2252         if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
2253                 options->detect_rename = DIFF_DETECT_COPY;
2254
2255         if (!DIFF_OPT_TST(options, RELATIVE_NAME))
2256                 options->prefix = NULL;
2257         if (options->prefix)
2258                 options->prefix_length = strlen(options->prefix);
2259         else
2260                 options->prefix_length = 0;
2261
2262         if (options->output_format & (DIFF_FORMAT_NAME |
2263                                       DIFF_FORMAT_NAME_STATUS |
2264                                       DIFF_FORMAT_CHECKDIFF |
2265                                       DIFF_FORMAT_NO_OUTPUT))
2266                 options->output_format &= ~(DIFF_FORMAT_RAW |
2267                                             DIFF_FORMAT_NUMSTAT |
2268                                             DIFF_FORMAT_DIFFSTAT |
2269                                             DIFF_FORMAT_SHORTSTAT |
2270                                             DIFF_FORMAT_DIRSTAT |
2271                                             DIFF_FORMAT_SUMMARY |
2272                                             DIFF_FORMAT_PATCH);
2273
2274         /*
2275          * These cases always need recursive; we do not drop caller-supplied
2276          * recursive bits for other formats here.
2277          */
2278         if (options->output_format & (DIFF_FORMAT_PATCH |
2279                                       DIFF_FORMAT_NUMSTAT |
2280                                       DIFF_FORMAT_DIFFSTAT |
2281                                       DIFF_FORMAT_SHORTSTAT |
2282                                       DIFF_FORMAT_DIRSTAT |
2283                                       DIFF_FORMAT_SUMMARY |
2284                                       DIFF_FORMAT_CHECKDIFF))
2285                 DIFF_OPT_SET(options, RECURSIVE);
2286         /*
2287          * Also pickaxe would not work very well if you do not say recursive
2288          */
2289         if (options->pickaxe)
2290                 DIFF_OPT_SET(options, RECURSIVE);
2291
2292         if (options->detect_rename && options->rename_limit < 0)
2293                 options->rename_limit = diff_rename_limit_default;
2294         if (options->setup & DIFF_SETUP_USE_CACHE) {
2295                 if (!active_cache)
2296                         /* read-cache does not die even when it fails
2297                          * so it is safe for us to do this here.  Also
2298                          * it does not smudge active_cache or active_nr
2299                          * when it fails, so we do not have to worry about
2300                          * cleaning it up ourselves either.
2301                          */
2302                         read_cache();
2303         }
2304         if (options->abbrev <= 0 || 40 < options->abbrev)
2305                 options->abbrev = 40; /* full */
2306
2307         /*
2308          * It does not make sense to show the first hit we happened
2309          * to have found.  It does not make sense not to return with
2310          * exit code in such a case either.
2311          */
2312         if (DIFF_OPT_TST(options, QUIET)) {
2313                 options->output_format = DIFF_FORMAT_NO_OUTPUT;
2314                 DIFF_OPT_SET(options, EXIT_WITH_STATUS);
2315         }
2316
2317         /*
2318          * If we postprocess in diffcore, we cannot simply return
2319          * upon the first hit.  We need to run diff as usual.
2320          */
2321         if (options->pickaxe || options->filter)
2322                 DIFF_OPT_CLR(options, QUIET);
2323
2324         return 0;
2325 }
2326
2327 static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
2328 {
2329         char c, *eq;
2330         int len;
2331
2332         if (*arg != '-')
2333                 return 0;
2334         c = *++arg;
2335         if (!c)
2336                 return 0;
2337         if (c == arg_short) {
2338                 c = *++arg;
2339                 if (!c)
2340                         return 1;
2341                 if (val && isdigit(c)) {
2342                         char *end;
2343                         int n = strtoul(arg, &end, 10);
2344                         if (*end)
2345                                 return 0;
2346                         *val = n;
2347                         return 1;
2348                 }
2349                 return 0;
2350         }
2351         if (c != '-')
2352                 return 0;
2353         arg++;
2354         eq = strchr(arg, '=');
2355         if (eq)
2356                 len = eq - arg;
2357         else
2358                 len = strlen(arg);
2359         if (!len || strncmp(arg, arg_long, len))
2360                 return 0;
2361         if (eq) {
2362                 int n;
2363                 char *end;
2364                 if (!isdigit(*++eq))
2365                         return 0;
2366                 n = strtoul(eq, &end, 10);
2367                 if (*end)
2368                         return 0;
2369                 *val = n;
2370         }
2371         return 1;
2372 }
2373
2374 static int diff_scoreopt_parse(const char *opt);
2375
2376 int diff_opt_parse(struct diff_options *options, const char **av, int ac)
2377 {
2378         const char *arg = av[0];
2379
2380         /* Output format options */
2381         if (!strcmp(arg, "-p") || !strcmp(arg, "-u"))
2382                 options->output_format |= DIFF_FORMAT_PATCH;
2383         else if (opt_arg(arg, 'U', "unified", &options->context))
2384                 options->output_format |= DIFF_FORMAT_PATCH;
2385         else if (!strcmp(arg, "--raw"))
2386                 options->output_format |= DIFF_FORMAT_RAW;
2387         else if (!strcmp(arg, "--patch-with-raw"))
2388                 options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_RAW;
2389         else if (!strcmp(arg, "--numstat"))
2390                 options->output_format |= DIFF_FORMAT_NUMSTAT;
2391         else if (!strcmp(arg, "--shortstat"))
2392                 options->output_format |= DIFF_FORMAT_SHORTSTAT;
2393         else if (opt_arg(arg, 'X', "dirstat", &options->dirstat_percent))
2394                 options->output_format |= DIFF_FORMAT_DIRSTAT;
2395         else if (!strcmp(arg, "--cumulative"))
2396                 options->output_format |= DIFF_FORMAT_CUMULATIVE;
2397         else if (!strcmp(arg, "--check"))
2398                 options->output_format |= DIFF_FORMAT_CHECKDIFF;
2399         else if (!strcmp(arg, "--summary"))
2400                 options->output_format |= DIFF_FORMAT_SUMMARY;
2401         else if (!strcmp(arg, "--patch-with-stat"))
2402                 options->output_format |= DIFF_FORMAT_PATCH | DIFF_FORMAT_DIFFSTAT;
2403         else if (!strcmp(arg, "--name-only"))
2404                 options->output_format |= DIFF_FORMAT_NAME;
2405         else if (!strcmp(arg, "--name-status"))
2406                 options->output_format |= DIFF_FORMAT_NAME_STATUS;
2407         else if (!strcmp(arg, "-s"))
2408                 options->output_format |= DIFF_FORMAT_NO_OUTPUT;
2409         else if (!prefixcmp(arg, "--stat")) {
2410                 char *end;
2411                 int width = options->stat_width;
2412                 int name_width = options->stat_name_width;
2413                 arg += 6;
2414                 end = (char *)arg;
2415
2416                 switch (*arg) {
2417                 case '-':
2418                         if (!prefixcmp(arg, "-width="))
2419                                 width = strtoul(arg + 7, &end, 10);
2420                         else if (!prefixcmp(arg, "-name-width="))
2421                                 name_width = strtoul(arg + 12, &end, 10);
2422                         break;
2423                 case '=':
2424                         width = strtoul(arg+1, &end, 10);
2425                         if (*end == ',')
2426                                 name_width = strtoul(end+1, &end, 10);
2427                 }
2428
2429                 /* Important! This checks all the error cases! */
2430                 if (*end)
2431                         return 0;
2432                 options->output_format |= DIFF_FORMAT_DIFFSTAT;
2433                 options->stat_name_width = name_width;
2434                 options->stat_width = width;
2435         }
2436
2437         /* renames options */
2438         else if (!prefixcmp(arg, "-B")) {
2439                 if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
2440                         return -1;
2441         }
2442         else if (!prefixcmp(arg, "-M")) {
2443                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
2444                         return -1;
2445                 options->detect_rename = DIFF_DETECT_RENAME;
2446         }
2447         else if (!prefixcmp(arg, "-C")) {
2448                 if (options->detect_rename == DIFF_DETECT_COPY)
2449                         DIFF_OPT_SET(options, FIND_COPIES_HARDER);
2450                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
2451                         return -1;
2452                 options->detect_rename = DIFF_DETECT_COPY;
2453         }
2454         else if (!strcmp(arg, "--no-renames"))
2455                 options->detect_rename = 0;
2456         else if (!strcmp(arg, "--relative"))
2457                 DIFF_OPT_SET(options, RELATIVE_NAME);
2458         else if (!prefixcmp(arg, "--relative=")) {
2459                 DIFF_OPT_SET(options, RELATIVE_NAME);
2460                 options->prefix = arg + 11;
2461         }
2462
2463         /* xdiff options */
2464         else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
2465                 options->xdl_opts |= XDF_IGNORE_WHITESPACE;
2466         else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
2467                 options->xdl_opts |= XDF_IGNORE_WHITESPACE_CHANGE;
2468         else if (!strcmp(arg, "--ignore-space-at-eol"))
2469                 options->xdl_opts |= XDF_IGNORE_WHITESPACE_AT_EOL;
2470
2471         /* flags options */
2472         else if (!strcmp(arg, "--binary")) {
2473                 options->output_format |= DIFF_FORMAT_PATCH;
2474                 DIFF_OPT_SET(options, BINARY);
2475         }
2476         else if (!strcmp(arg, "--full-index"))
2477                 DIFF_OPT_SET(options, FULL_INDEX);
2478         else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
2479                 DIFF_OPT_SET(options, TEXT);
2480         else if (!strcmp(arg, "-R"))
2481                 DIFF_OPT_SET(options, REVERSE_DIFF);
2482         else if (!strcmp(arg, "--find-copies-harder"))
2483                 DIFF_OPT_SET(options, FIND_COPIES_HARDER);
2484         else if (!strcmp(arg, "--follow"))
2485                 DIFF_OPT_SET(options, FOLLOW_RENAMES);
2486         else if (!strcmp(arg, "--color"))
2487                 DIFF_OPT_SET(options, COLOR_DIFF);
2488         else if (!strcmp(arg, "--no-color"))
2489                 DIFF_OPT_CLR(options, COLOR_DIFF);
2490         else if (!strcmp(arg, "--color-words"))
2491                 options->flags |= DIFF_OPT_COLOR_DIFF | DIFF_OPT_COLOR_DIFF_WORDS;
2492         else if (!strcmp(arg, "--exit-code"))
2493                 DIFF_OPT_SET(options, EXIT_WITH_STATUS);
2494         else if (!strcmp(arg, "--quiet"))
2495                 DIFF_OPT_SET(options, QUIET);
2496         else if (!strcmp(arg, "--ext-diff"))
2497                 DIFF_OPT_SET(options, ALLOW_EXTERNAL);
2498         else if (!strcmp(arg, "--no-ext-diff"))
2499                 DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
2500
2501         /* misc options */
2502         else if (!strcmp(arg, "-z"))
2503                 options->line_termination = 0;
2504         else if (!prefixcmp(arg, "-l"))
2505                 options->rename_limit = strtoul(arg+2, NULL, 10);
2506         else if (!prefixcmp(arg, "-S"))
2507                 options->pickaxe = arg + 2;
2508         else if (!strcmp(arg, "--pickaxe-all"))
2509                 options->pickaxe_opts = DIFF_PICKAXE_ALL;
2510         else if (!strcmp(arg, "--pickaxe-regex"))
2511                 options->pickaxe_opts = DIFF_PICKAXE_REGEX;
2512         else if (!prefixcmp(arg, "-O"))
2513                 options->orderfile = arg + 2;
2514         else if (!prefixcmp(arg, "--diff-filter="))
2515                 options->filter = arg + 14;
2516         else if (!strcmp(arg, "--abbrev"))
2517                 options->abbrev = DEFAULT_ABBREV;
2518         else if (!prefixcmp(arg, "--abbrev=")) {
2519                 options->abbrev = strtoul(arg + 9, NULL, 10);
2520                 if (options->abbrev < MINIMUM_ABBREV)
2521                         options->abbrev = MINIMUM_ABBREV;
2522                 else if (40 < options->abbrev)
2523                         options->abbrev = 40;
2524         }
2525         else if (!prefixcmp(arg, "--src-prefix="))
2526                 options->a_prefix = arg + 13;
2527         else if (!prefixcmp(arg, "--dst-prefix="))
2528                 options->b_prefix = arg + 13;
2529         else if (!strcmp(arg, "--no-prefix"))
2530                 options->a_prefix = options->b_prefix = "";
2531         else if (!prefixcmp(arg, "--output=")) {
2532                 options->file = fopen(arg + strlen("--output="), "w");
2533                 options->close_file = 1;
2534         } else
2535                 return 0;
2536         return 1;
2537 }
2538
2539 static int parse_num(const char **cp_p)
2540 {
2541         unsigned long num, scale;
2542         int ch, dot;
2543         const char *cp = *cp_p;
2544
2545         num = 0;
2546         scale = 1;
2547         dot = 0;
2548         for(;;) {
2549                 ch = *cp;
2550                 if ( !dot && ch == '.' ) {
2551                         scale = 1;
2552                         dot = 1;
2553                 } else if ( ch == '%' ) {
2554                         scale = dot ? scale*100 : 100;
2555                         cp++;   /* % is always at the end */
2556                         break;
2557                 } else if ( ch >= '0' && ch <= '9' ) {
2558                         if ( scale < 100000 ) {
2559                                 scale *= 10;
2560                                 num = (num*10) + (ch-'0');
2561                         }
2562                 } else {
2563                         break;
2564                 }
2565                 cp++;
2566         }
2567         *cp_p = cp;
2568
2569         /* user says num divided by scale and we say internally that
2570          * is MAX_SCORE * num / scale.
2571          */
2572         return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
2573 }
2574
2575 static int diff_scoreopt_parse(const char *opt)
2576 {
2577         int opt1, opt2, cmd;
2578
2579         if (*opt++ != '-')
2580                 return -1;
2581         cmd = *opt++;
2582         if (cmd != 'M' && cmd != 'C' && cmd != 'B')
2583                 return -1; /* that is not a -M, -C nor -B option */
2584
2585         opt1 = parse_num(&opt);
2586         if (cmd != 'B')
2587                 opt2 = 0;
2588         else {
2589                 if (*opt == 0)
2590                         opt2 = 0;
2591                 else if (*opt != '/')
2592                         return -1; /* we expect -B80/99 or -B80 */
2593                 else {
2594                         opt++;
2595                         opt2 = parse_num(&opt);
2596                 }
2597         }
2598         if (*opt != 0)
2599                 return -1;
2600         return opt1 | (opt2 << 16);
2601 }
2602
2603 struct diff_queue_struct diff_queued_diff;
2604
2605 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
2606 {
2607         if (queue->alloc <= queue->nr) {
2608                 queue->alloc = alloc_nr(queue->alloc);
2609                 queue->queue = xrealloc(queue->queue,
2610                                         sizeof(dp) * queue->alloc);
2611         }
2612         queue->queue[queue->nr++] = dp;
2613 }
2614
2615 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
2616                                  struct diff_filespec *one,
2617                                  struct diff_filespec *two)
2618 {
2619         struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
2620         dp->one = one;
2621         dp->two = two;
2622         if (queue)
2623                 diff_q(queue, dp);
2624         return dp;
2625 }
2626
2627 void diff_free_filepair(struct diff_filepair *p)
2628 {
2629         free_filespec(p->one);
2630         free_filespec(p->two);
2631         free(p);
2632 }
2633
2634 /* This is different from find_unique_abbrev() in that
2635  * it stuffs the result with dots for alignment.
2636  */
2637 const char *diff_unique_abbrev(const unsigned char *sha1, int len)
2638 {
2639         int abblen;
2640         const char *abbrev;
2641         if (len == 40)
2642                 return sha1_to_hex(sha1);
2643
2644         abbrev = find_unique_abbrev(sha1, len);
2645         abblen = strlen(abbrev);
2646         if (abblen < 37) {
2647                 static char hex[41];
2648                 if (len < abblen && abblen <= len + 2)
2649                         sprintf(hex, "%s%.*s", abbrev, len+3-abblen, "..");
2650                 else
2651                         sprintf(hex, "%s...", abbrev);
2652                 return hex;
2653         }
2654         return sha1_to_hex(sha1);
2655 }
2656
2657 static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
2658 {
2659         int line_termination = opt->line_termination;
2660         int inter_name_termination = line_termination ? '\t' : '\0';
2661
2662         if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
2663                 fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
2664                         diff_unique_abbrev(p->one->sha1, opt->abbrev));
2665                 fprintf(opt->file, "%s ", diff_unique_abbrev(p->two->sha1, opt->abbrev));
2666         }
2667         if (p->score) {
2668                 fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
2669                         inter_name_termination);
2670         } else {
2671                 fprintf(opt->file, "%c%c", p->status, inter_name_termination);
2672         }
2673
2674         if (p->status == DIFF_STATUS_COPIED ||
2675             p->status == DIFF_STATUS_RENAMED) {
2676                 const char *name_a, *name_b;
2677                 name_a = p->one->path;
2678                 name_b = p->two->path;
2679                 strip_prefix(opt->prefix_length, &name_a, &name_b);
2680                 write_name_quoted(name_a, opt->file, inter_name_termination);
2681                 write_name_quoted(name_b, opt->file, line_termination);
2682         } else {
2683                 const char *name_a, *name_b;
2684                 name_a = p->one->mode ? p->one->path : p->two->path;
2685                 name_b = NULL;
2686                 strip_prefix(opt->prefix_length, &name_a, &name_b);
2687                 write_name_quoted(name_a, opt->file, line_termination);
2688         }
2689 }
2690
2691 int diff_unmodified_pair(struct diff_filepair *p)
2692 {
2693         /* This function is written stricter than necessary to support
2694          * the currently implemented transformers, but the idea is to
2695          * let transformers to produce diff_filepairs any way they want,
2696          * and filter and clean them up here before producing the output.
2697          */
2698         struct diff_filespec *one = p->one, *two = p->two;
2699
2700         if (DIFF_PAIR_UNMERGED(p))
2701                 return 0; /* unmerged is interesting */
2702
2703         /* deletion, addition, mode or type change
2704          * and rename are all interesting.
2705          */
2706         if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
2707             DIFF_PAIR_MODE_CHANGED(p) ||
2708             strcmp(one->path, two->path))
2709                 return 0;
2710
2711         /* both are valid and point at the same path.  that is, we are
2712          * dealing with a change.
2713          */
2714         if (one->sha1_valid && two->sha1_valid &&
2715             !hashcmp(one->sha1, two->sha1))
2716                 return 1; /* no change */
2717         if (!one->sha1_valid && !two->sha1_valid)
2718                 return 1; /* both look at the same file on the filesystem. */
2719         return 0;
2720 }
2721
2722 static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
2723 {
2724         if (diff_unmodified_pair(p))
2725                 return;
2726
2727         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
2728             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
2729                 return; /* no tree diffs in patch format */
2730
2731         run_diff(p, o);
2732 }
2733
2734 static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
2735                             struct diffstat_t *diffstat)
2736 {
2737         if (diff_unmodified_pair(p))
2738                 return;
2739
2740         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
2741             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
2742                 return; /* no tree diffs in patch format */
2743
2744         run_diffstat(p, o, diffstat);
2745 }
2746
2747 static void diff_flush_checkdiff(struct diff_filepair *p,
2748                 struct diff_options *o)
2749 {
2750         if (diff_unmodified_pair(p))
2751                 return;
2752
2753         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
2754             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
2755                 return; /* no tree diffs in patch format */
2756
2757         run_checkdiff(p, o);
2758 }
2759
2760 int diff_queue_is_empty(void)
2761 {
2762         struct diff_queue_struct *q = &diff_queued_diff;
2763         int i;
2764         for (i = 0; i < q->nr; i++)
2765                 if (!diff_unmodified_pair(q->queue[i]))
2766                         return 0;
2767         return 1;
2768 }
2769
2770 #if DIFF_DEBUG
2771 void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
2772 {
2773         fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
2774                 x, one ? one : "",
2775                 s->path,
2776                 DIFF_FILE_VALID(s) ? "valid" : "invalid",
2777                 s->mode,
2778                 s->sha1_valid ? sha1_to_hex(s->sha1) : "");
2779         fprintf(stderr, "queue[%d] %s size %lu flags %d\n",
2780                 x, one ? one : "",
2781                 s->size, s->xfrm_flags);
2782 }
2783
2784 void diff_debug_filepair(const struct diff_filepair *p, int i)
2785 {
2786         diff_debug_filespec(p->one, i, "one");
2787         diff_debug_filespec(p->two, i, "two");
2788         fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
2789                 p->score, p->status ? p->status : '?',
2790                 p->one->rename_used, p->broken_pair);
2791 }
2792
2793 void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
2794 {
2795         int i;
2796         if (msg)
2797                 fprintf(stderr, "%s\n", msg);
2798         fprintf(stderr, "q->nr = %d\n", q->nr);
2799         for (i = 0; i < q->nr; i++) {
2800                 struct diff_filepair *p = q->queue[i];
2801                 diff_debug_filepair(p, i);
2802         }
2803 }
2804 #endif
2805
2806 static void diff_resolve_rename_copy(void)
2807 {
2808         int i;
2809         struct diff_filepair *p;
2810         struct diff_queue_struct *q = &diff_queued_diff;
2811
2812         diff_debug_queue("resolve-rename-copy", q);
2813
2814         for (i = 0; i < q->nr; i++) {
2815                 p = q->queue[i];
2816                 p->status = 0; /* undecided */
2817                 if (DIFF_PAIR_UNMERGED(p))
2818                         p->status = DIFF_STATUS_UNMERGED;
2819                 else if (!DIFF_FILE_VALID(p->one))
2820                         p->status = DIFF_STATUS_ADDED;
2821                 else if (!DIFF_FILE_VALID(p->two))
2822                         p->status = DIFF_STATUS_DELETED;
2823                 else if (DIFF_PAIR_TYPE_CHANGED(p))
2824                         p->status = DIFF_STATUS_TYPE_CHANGED;
2825
2826                 /* from this point on, we are dealing with a pair
2827                  * whose both sides are valid and of the same type, i.e.
2828                  * either in-place edit or rename/copy edit.
2829                  */
2830                 else if (DIFF_PAIR_RENAME(p)) {
2831                         /*
2832                          * A rename might have re-connected a broken
2833                          * pair up, causing the pathnames to be the
2834                          * same again. If so, that's not a rename at
2835                          * all, just a modification..
2836                          *
2837                          * Otherwise, see if this source was used for
2838                          * multiple renames, in which case we decrement
2839                          * the count, and call it a copy.
2840                          */
2841                         if (!strcmp(p->one->path, p->two->path))
2842                                 p->status = DIFF_STATUS_MODIFIED;
2843                         else if (--p->one->rename_used > 0)
2844                                 p->status = DIFF_STATUS_COPIED;
2845                         else
2846                                 p->status = DIFF_STATUS_RENAMED;
2847                 }
2848                 else if (hashcmp(p->one->sha1, p->two->sha1) ||
2849                          p->one->mode != p->two->mode ||
2850                          is_null_sha1(p->one->sha1))
2851                         p->status = DIFF_STATUS_MODIFIED;
2852                 else {
2853                         /* This is a "no-change" entry and should not
2854                          * happen anymore, but prepare for broken callers.
2855                          */
2856                         error("feeding unmodified %s to diffcore",
2857                               p->one->path);
2858                         p->status = DIFF_STATUS_UNKNOWN;
2859                 }
2860         }
2861         diff_debug_queue("resolve-rename-copy done", q);
2862 }
2863
2864 static int check_pair_status(struct diff_filepair *p)
2865 {
2866         switch (p->status) {
2867         case DIFF_STATUS_UNKNOWN:
2868                 return 0;
2869         case 0:
2870                 die("internal error in diff-resolve-rename-copy");
2871         default:
2872                 return 1;
2873         }
2874 }
2875
2876 static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
2877 {
2878         int fmt = opt->output_format;
2879
2880         if (fmt & DIFF_FORMAT_CHECKDIFF)
2881                 diff_flush_checkdiff(p, opt);
2882         else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
2883                 diff_flush_raw(p, opt);
2884         else if (fmt & DIFF_FORMAT_NAME) {
2885                 const char *name_a, *name_b;
2886                 name_a = p->two->path;
2887                 name_b = NULL;
2888                 strip_prefix(opt->prefix_length, &name_a, &name_b);
2889                 write_name_quoted(name_a, opt->file, opt->line_termination);
2890         }
2891 }
2892
2893 static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
2894 {
2895         if (fs->mode)
2896                 fprintf(file, " %s mode %06o ", newdelete, fs->mode);
2897         else
2898                 fprintf(file, " %s ", newdelete);
2899         write_name_quoted(fs->path, file, '\n');
2900 }
2901
2902
2903 static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name)
2904 {
2905         if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
2906                 fprintf(file, " mode change %06o => %06o%c", p->one->mode, p->two->mode,
2907                         show_name ? ' ' : '\n');
2908                 if (show_name) {
2909                         write_name_quoted(p->two->path, file, '\n');
2910                 }
2911         }
2912 }
2913
2914 static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p)
2915 {
2916         char *names = pprint_rename(p->one->path, p->two->path);
2917
2918         fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
2919         free(names);
2920         show_mode_change(file, p, 0);
2921 }
2922
2923 static void diff_summary(FILE *file, struct diff_filepair *p)
2924 {
2925         switch(p->status) {
2926         case DIFF_STATUS_DELETED:
2927                 show_file_mode_name(file, "delete", p->one);
2928                 break;
2929         case DIFF_STATUS_ADDED:
2930                 show_file_mode_name(file, "create", p->two);
2931                 break;
2932         case DIFF_STATUS_COPIED:
2933                 show_rename_copy(file, "copy", p);
2934                 break;
2935         case DIFF_STATUS_RENAMED:
2936                 show_rename_copy(file, "rename", p);
2937                 break;
2938         default:
2939                 if (p->score) {
2940                         fputs(" rewrite ", file);
2941                         write_name_quoted(p->two->path, file, ' ');
2942                         fprintf(file, "(%d%%)\n", similarity_index(p));
2943                 }
2944                 show_mode_change(file, p, !p->score);
2945                 break;
2946         }
2947 }
2948
2949 struct patch_id_t {
2950         struct xdiff_emit_state xm;
2951         SHA_CTX *ctx;
2952         int patchlen;
2953 };
2954
2955 static int remove_space(char *line, int len)
2956 {
2957         int i;
2958         char *dst = line;
2959         unsigned char c;
2960
2961         for (i = 0; i < len; i++)
2962                 if (!isspace((c = line[i])))
2963                         *dst++ = c;
2964
2965         return dst - line;
2966 }
2967
2968 static void patch_id_consume(void *priv, char *line, unsigned long len)
2969 {
2970         struct patch_id_t *data = priv;
2971         int new_len;
2972
2973         /* Ignore line numbers when computing the SHA1 of the patch */
2974         if (!prefixcmp(line, "@@ -"))
2975                 return;
2976
2977         new_len = remove_space(line, len);
2978
2979         SHA1_Update(data->ctx, line, new_len);
2980         data->patchlen += new_len;
2981 }
2982
2983 /* returns 0 upon success, and writes result into sha1 */
2984 static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
2985 {
2986         struct diff_queue_struct *q = &diff_queued_diff;
2987         int i;
2988         SHA_CTX ctx;
2989         struct patch_id_t data;
2990         char buffer[PATH_MAX * 4 + 20];
2991
2992         SHA1_Init(&ctx);
2993         memset(&data, 0, sizeof(struct patch_id_t));
2994         data.ctx = &ctx;
2995         data.xm.consume = patch_id_consume;
2996
2997         for (i = 0; i < q->nr; i++) {
2998                 xpparam_t xpp;
2999                 xdemitconf_t xecfg;
3000                 xdemitcb_t ecb;
3001                 mmfile_t mf1, mf2;
3002                 struct diff_filepair *p = q->queue[i];
3003                 int len1, len2;
3004
3005                 memset(&xecfg, 0, sizeof(xecfg));
3006                 if (p->status == 0)
3007                         return error("internal diff status error");
3008                 if (p->status == DIFF_STATUS_UNKNOWN)
3009                         continue;
3010                 if (diff_unmodified_pair(p))
3011                         continue;
3012                 if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
3013                     (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
3014                         continue;
3015                 if (DIFF_PAIR_UNMERGED(p))
3016                         continue;
3017
3018                 diff_fill_sha1_info(p->one);
3019                 diff_fill_sha1_info(p->two);
3020                 if (fill_mmfile(&mf1, p->one) < 0 ||
3021                                 fill_mmfile(&mf2, p->two) < 0)
3022                         return error("unable to read files to diff");
3023
3024                 len1 = remove_space(p->one->path, strlen(p->one->path));
3025                 len2 = remove_space(p->two->path, strlen(p->two->path));
3026                 if (p->one->mode == 0)
3027                         len1 = snprintf(buffer, sizeof(buffer),
3028                                         "diff--gita/%.*sb/%.*s"
3029                                         "newfilemode%06o"
3030                                         "---/dev/null"
3031                                         "+++b/%.*s",
3032                                         len1, p->one->path,
3033                                         len2, p->two->path,
3034                                         p->two->mode,
3035                                         len2, p->two->path);
3036                 else if (p->two->mode == 0)
3037                         len1 = snprintf(buffer, sizeof(buffer),
3038                                         "diff--gita/%.*sb/%.*s"
3039                                         "deletedfilemode%06o"
3040                                         "---a/%.*s"
3041                                         "+++/dev/null",
3042                                         len1, p->one->path,
3043                                         len2, p->two->path,
3044                                         p->one->mode,
3045                                         len1, p->one->path);
3046                 else
3047                         len1 = snprintf(buffer, sizeof(buffer),
3048                                         "diff--gita/%.*sb/%.*s"
3049                                         "---a/%.*s"
3050                                         "+++b/%.*s",
3051                                         len1, p->one->path,
3052                                         len2, p->two->path,
3053                                         len1, p->one->path,
3054                                         len2, p->two->path);
3055                 SHA1_Update(&ctx, buffer, len1);
3056
3057                 xpp.flags = XDF_NEED_MINIMAL;
3058                 xecfg.ctxlen = 3;
3059                 xecfg.flags = XDL_EMIT_FUNCNAMES;
3060                 ecb.outf = xdiff_outf;
3061                 ecb.priv = &data;
3062                 xdi_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
3063         }
3064
3065         SHA1_Final(sha1, &ctx);
3066         return 0;
3067 }
3068
3069 int diff_flush_patch_id(struct diff_options *options, unsigned char *sha1)
3070 {
3071         struct diff_queue_struct *q = &diff_queued_diff;
3072         int i;
3073         int result = diff_get_patch_id(options, sha1);
3074
3075         for (i = 0; i < q->nr; i++)
3076                 diff_free_filepair(q->queue[i]);
3077
3078         free(q->queue);
3079         q->queue = NULL;
3080         q->nr = q->alloc = 0;
3081
3082         return result;
3083 }
3084
3085 static int is_summary_empty(const struct diff_queue_struct *q)
3086 {
3087         int i;
3088
3089         for (i = 0; i < q->nr; i++) {
3090                 const struct diff_filepair *p = q->queue[i];
3091
3092                 switch (p->status) {
3093                 case DIFF_STATUS_DELETED:
3094                 case DIFF_STATUS_ADDED:
3095                 case DIFF_STATUS_COPIED:
3096                 case DIFF_STATUS_RENAMED:
3097                         return 0;
3098                 default:
3099                         if (p->score)
3100                                 return 0;
3101                         if (p->one->mode && p->two->mode &&
3102                             p->one->mode != p->two->mode)
3103                                 return 0;
3104                         break;
3105                 }
3106         }
3107         return 1;
3108 }
3109
3110 void diff_flush(struct diff_options *options)
3111 {
3112         struct diff_queue_struct *q = &diff_queued_diff;
3113         int i, output_format = options->output_format;
3114         int separator = 0;
3115
3116         /*
3117          * Order: raw, stat, summary, patch
3118          * or:    name/name-status/checkdiff (other bits clear)
3119          */
3120         if (!q->nr)
3121                 goto free_queue;
3122
3123         if (output_format & (DIFF_FORMAT_RAW |
3124                              DIFF_FORMAT_NAME |
3125                              DIFF_FORMAT_NAME_STATUS |
3126                              DIFF_FORMAT_CHECKDIFF)) {
3127                 for (i = 0; i < q->nr; i++) {
3128                         struct diff_filepair *p = q->queue[i];
3129                         if (check_pair_status(p))
3130                                 flush_one_pair(p, options);
3131                 }
3132                 separator++;
3133         }
3134
3135         if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT)) {
3136                 struct diffstat_t diffstat;
3137
3138                 memset(&diffstat, 0, sizeof(struct diffstat_t));
3139                 diffstat.xm.consume = diffstat_consume;
3140                 for (i = 0; i < q->nr; i++) {
3141                         struct diff_filepair *p = q->queue[i];
3142                         if (check_pair_status(p))
3143                                 diff_flush_stat(p, options, &diffstat);
3144                 }
3145                 if (output_format & DIFF_FORMAT_NUMSTAT)
3146                         show_numstat(&diffstat, options);
3147                 if (output_format & DIFF_FORMAT_DIFFSTAT)
3148                         show_stats(&diffstat, options);
3149                 if (output_format & DIFF_FORMAT_SHORTSTAT)
3150                         show_shortstats(&diffstat, options);
3151                 free_diffstat_info(&diffstat);
3152                 separator++;
3153         }
3154         if (output_format & DIFF_FORMAT_DIRSTAT)
3155                 show_dirstat(options);
3156
3157         if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
3158                 for (i = 0; i < q->nr; i++)
3159                         diff_summary(options->file, q->queue[i]);
3160                 separator++;
3161         }
3162
3163         if (output_format & DIFF_FORMAT_PATCH) {
3164                 if (separator) {
3165                         if (options->stat_sep) {
3166                                 /* attach patch instead of inline */
3167                                 fputs(options->stat_sep, options->file);
3168                         } else {
3169                                 putc(options->line_termination, options->file);
3170                         }
3171                 }
3172
3173                 for (i = 0; i < q->nr; i++) {
3174                         struct diff_filepair *p = q->queue[i];
3175                         if (check_pair_status(p))
3176                                 diff_flush_patch(p, options);
3177                 }
3178         }
3179
3180         if (output_format & DIFF_FORMAT_CALLBACK)
3181                 options->format_callback(q, options, options->format_callback_data);
3182
3183         for (i = 0; i < q->nr; i++)
3184                 diff_free_filepair(q->queue[i]);
3185 free_queue:
3186         free(q->queue);
3187         q->queue = NULL;
3188         q->nr = q->alloc = 0;
3189         if (options->close_file)
3190                 fclose(options->file);
3191 }
3192
3193 static void diffcore_apply_filter(const char *filter)
3194 {
3195         int i;
3196         struct diff_queue_struct *q = &diff_queued_diff;
3197         struct diff_queue_struct outq;
3198         outq.queue = NULL;
3199         outq.nr = outq.alloc = 0;
3200
3201         if (!filter)
3202                 return;
3203
3204         if (strchr(filter, DIFF_STATUS_FILTER_AON)) {
3205                 int found;
3206                 for (i = found = 0; !found && i < q->nr; i++) {
3207                         struct diff_filepair *p = q->queue[i];
3208                         if (((p->status == DIFF_STATUS_MODIFIED) &&
3209                              ((p->score &&
3210                                strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
3211                               (!p->score &&
3212                                strchr(filter, DIFF_STATUS_MODIFIED)))) ||
3213                             ((p->status != DIFF_STATUS_MODIFIED) &&
3214                              strchr(filter, p->status)))
3215                                 found++;
3216                 }
3217                 if (found)
3218                         return;
3219
3220                 /* otherwise we will clear the whole queue
3221                  * by copying the empty outq at the end of this
3222                  * function, but first clear the current entries
3223                  * in the queue.
3224                  */
3225                 for (i = 0; i < q->nr; i++)
3226                         diff_free_filepair(q->queue[i]);
3227         }
3228         else {
3229                 /* Only the matching ones */
3230                 for (i = 0; i < q->nr; i++) {
3231                         struct diff_filepair *p = q->queue[i];
3232
3233                         if (((p->status == DIFF_STATUS_MODIFIED) &&
3234                              ((p->score &&
3235                                strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
3236                               (!p->score &&
3237                                strchr(filter, DIFF_STATUS_MODIFIED)))) ||
3238                             ((p->status != DIFF_STATUS_MODIFIED) &&
3239                              strchr(filter, p->status)))
3240                                 diff_q(&outq, p);
3241                         else
3242                                 diff_free_filepair(p);
3243                 }
3244         }
3245         free(q->queue);
3246         *q = outq;
3247 }
3248
3249 /* Check whether two filespecs with the same mode and size are identical */
3250 static int diff_filespec_is_identical(struct diff_filespec *one,
3251                                       struct diff_filespec *two)
3252 {
3253         if (S_ISGITLINK(one->mode))
3254                 return 0;
3255         if (diff_populate_filespec(one, 0))
3256                 return 0;
3257         if (diff_populate_filespec(two, 0))
3258                 return 0;
3259         return !memcmp(one->data, two->data, one->size);
3260 }
3261
3262 static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
3263 {
3264         int i;
3265         struct diff_queue_struct *q = &diff_queued_diff;
3266         struct diff_queue_struct outq;
3267         outq.queue = NULL;
3268         outq.nr = outq.alloc = 0;
3269
3270         for (i = 0; i < q->nr; i++) {
3271                 struct diff_filepair *p = q->queue[i];
3272
3273                 /*
3274                  * 1. Entries that come from stat info dirtyness
3275                  *    always have both sides (iow, not create/delete),
3276                  *    one side of the object name is unknown, with
3277                  *    the same mode and size.  Keep the ones that
3278                  *    do not match these criteria.  They have real
3279                  *    differences.
3280                  *
3281                  * 2. At this point, the file is known to be modified,
3282                  *    with the same mode and size, and the object
3283                  *    name of one side is unknown.  Need to inspect
3284                  *    the identical contents.
3285                  */
3286                 if (!DIFF_FILE_VALID(p->one) || /* (1) */
3287                     !DIFF_FILE_VALID(p->two) ||
3288                     (p->one->sha1_valid && p->two->sha1_valid) ||
3289                     (p->one->mode != p->two->mode) ||
3290                     diff_populate_filespec(p->one, 1) ||
3291                     diff_populate_filespec(p->two, 1) ||
3292                     (p->one->size != p->two->size) ||
3293                     !diff_filespec_is_identical(p->one, p->two)) /* (2) */
3294                         diff_q(&outq, p);
3295                 else {
3296                         /*
3297                          * The caller can subtract 1 from skip_stat_unmatch
3298                          * to determine how many paths were dirty only
3299                          * due to stat info mismatch.
3300                          */
3301                         if (!DIFF_OPT_TST(diffopt, NO_INDEX))
3302                                 diffopt->skip_stat_unmatch++;
3303                         diff_free_filepair(p);
3304                 }
3305         }
3306         free(q->queue);
3307         *q = outq;
3308 }
3309
3310 void diffcore_std(struct diff_options *options)
3311 {
3312         if (DIFF_OPT_TST(options, QUIET))
3313                 return;
3314
3315         if (options->skip_stat_unmatch && !DIFF_OPT_TST(options, FIND_COPIES_HARDER))
3316                 diffcore_skip_stat_unmatch(options);
3317         if (options->break_opt != -1)
3318                 diffcore_break(options->break_opt);
3319         if (options->detect_rename)
3320                 diffcore_rename(options);
3321         if (options->break_opt != -1)
3322                 diffcore_merge_broken();
3323         if (options->pickaxe)
3324                 diffcore_pickaxe(options->pickaxe, options->pickaxe_opts);
3325         if (options->orderfile)
3326                 diffcore_order(options->orderfile);
3327         diff_resolve_rename_copy();
3328         diffcore_apply_filter(options->filter);
3329
3330         if (diff_queued_diff.nr)
3331                 DIFF_OPT_SET(options, HAS_CHANGES);
3332         else
3333                 DIFF_OPT_CLR(options, HAS_CHANGES);
3334 }
3335
3336 int diff_result_code(struct diff_options *opt, int status)
3337 {
3338         int result = 0;
3339         if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
3340             !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
3341                 return status;
3342         if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
3343             DIFF_OPT_TST(opt, HAS_CHANGES))
3344                 result |= 01;
3345         if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
3346             DIFF_OPT_TST(opt, CHECK_FAILED))
3347                 result |= 02;
3348         return result;
3349 }
3350
3351 void diff_addremove(struct diff_options *options,
3352                     int addremove, unsigned mode,
3353                     const unsigned char *sha1,
3354                     const char *base, const char *path)
3355 {
3356         char concatpath[PATH_MAX];
3357         struct diff_filespec *one, *two;
3358
3359         /* This may look odd, but it is a preparation for
3360          * feeding "there are unchanged files which should
3361          * not produce diffs, but when you are doing copy
3362          * detection you would need them, so here they are"
3363          * entries to the diff-core.  They will be prefixed
3364          * with something like '=' or '*' (I haven't decided
3365          * which but should not make any difference).
3366          * Feeding the same new and old to diff_change()
3367          * also has the same effect.
3368          * Before the final output happens, they are pruned after
3369          * merged into rename/copy pairs as appropriate.
3370          */
3371         if (DIFF_OPT_TST(options, REVERSE_DIFF))
3372                 addremove = (addremove == '+' ? '-' :
3373                              addremove == '-' ? '+' : addremove);
3374
3375         if (!path) path = "";
3376         sprintf(concatpath, "%s%s", base, path);
3377
3378         if (options->prefix &&
3379             strncmp(concatpath, options->prefix, options->prefix_length))
3380                 return;
3381
3382         one = alloc_filespec(concatpath);
3383         two = alloc_filespec(concatpath);
3384
3385         if (addremove != '+')
3386                 fill_filespec(one, sha1, mode);
3387         if (addremove != '-')
3388                 fill_filespec(two, sha1, mode);
3389
3390         diff_queue(&diff_queued_diff, one, two);
3391         DIFF_OPT_SET(options, HAS_CHANGES);
3392 }
3393
3394 void diff_change(struct diff_options *options,
3395                  unsigned old_mode, unsigned new_mode,
3396                  const unsigned char *old_sha1,
3397                  const unsigned char *new_sha1,
3398                  const char *base, const char *path)
3399 {
3400         char concatpath[PATH_MAX];
3401         struct diff_filespec *one, *two;
3402
3403         if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
3404                 unsigned tmp;
3405                 const unsigned char *tmp_c;
3406                 tmp = old_mode; old_mode = new_mode; new_mode = tmp;
3407                 tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
3408         }
3409         if (!path) path = "";
3410         sprintf(concatpath, "%s%s", base, path);
3411
3412         if (options->prefix &&
3413             strncmp(concatpath, options->prefix, options->prefix_length))
3414                 return;
3415
3416         one = alloc_filespec(concatpath);
3417         two = alloc_filespec(concatpath);
3418         fill_filespec(one, old_sha1, old_mode);
3419         fill_filespec(two, new_sha1, new_mode);
3420
3421         diff_queue(&diff_queued_diff, one, two);
3422         DIFF_OPT_SET(options, HAS_CHANGES);
3423 }
3424
3425 void diff_unmerge(struct diff_options *options,
3426                   const char *path,
3427                   unsigned mode, const unsigned char *sha1)
3428 {
3429         struct diff_filespec *one, *two;
3430
3431         if (options->prefix &&
3432             strncmp(path, options->prefix, options->prefix_length))
3433                 return;
3434
3435         one = alloc_filespec(path);
3436         two = alloc_filespec(path);
3437         fill_filespec(one, sha1, mode);
3438         diff_queue(&diff_queued_diff, one, two)->is_unmerged = 1;
3439 }