diff.c

   1 /*
   2  * Copyright (C) 2005 Junio C Hamano
   3  */
   4 #include <sys/types.h>
   5 #include <sys/wait.h>
   6 #include <signal.h>
   7 #include "cache.h"
   8 #include "quote.h"
   9 #include "diff.h"
  10 #include "diffcore.h"
  11 #include "delta.h"
  12 #include "xdiff-interface.h"
  13
  14 static int use_size_cache;
  15
  16 int diff_rename_limit_default = -1;
  17
  18 int git_diff_config(const char *var, const char *value)
  19 {
  20         if (!strcmp(var, "diff.renamelimit")) {
  21                 diff_rename_limit_default = git_config_int(var, value);
  22                 return 0;
  23         }
  24
  25         return git_default_config(var, value);
  26 }
  27
  28 static char *quote_one(const char *str)
  29 {
  30         int needlen;
  31         char *xp;
  32
  33         if (!str)
  34                 return NULL;
  35         needlen = quote_c_style(str, NULL, NULL, 0);
  36         if (!needlen)
  37                 return strdup(str);
  38         xp = xmalloc(needlen + 1);
  39         quote_c_style(str, xp, NULL, 0);
  40         return xp;
  41 }
  42
  43 static char *quote_two(const char *one, const char *two)
  44 {
  45         int need_one = quote_c_style(one, NULL, NULL, 1);
  46         int need_two = quote_c_style(two, NULL, NULL, 1);
  47         char *xp;
  48
  49         if (need_one + need_two) {
  50                 if (!need_one) need_one = strlen(one);
  51                 if (!need_two) need_one = strlen(two);
  52
  53                 xp = xmalloc(need_one + need_two + 3);
  54                 xp[0] = '"';
  55                 quote_c_style(one, xp + 1, NULL, 1);
  56                 quote_c_style(two, xp + need_one + 1, NULL, 1);
  57                 strcpy(xp + need_one + need_two + 1, "\"");
  58                 return xp;
  59         }
  60         need_one = strlen(one);
  61         need_two = strlen(two);
  62         xp = xmalloc(need_one + need_two + 1);
  63         strcpy(xp, one);
  64         strcpy(xp + need_one, two);
  65         return xp;
  66 }
  67
  68 static const char *external_diff(void)
  69 {
  70         static const char *external_diff_cmd = NULL;
  71         static int done_preparing = 0;
  72
  73         if (done_preparing)
  74                 return external_diff_cmd;
  75         external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
  76         done_preparing = 1;
  77         return external_diff_cmd;
  78 }
  79
  80 #define TEMPFILE_PATH_LEN               50
  81
  82 static struct diff_tempfile {
  83         const char *name; /* filename external diff should read from */
  84         char hex[41];
  85         char mode[10];
  86         char tmp_path[TEMPFILE_PATH_LEN];
  87 } diff_temp[2];
  88
  89 static int count_lines(const char *data, int size)
  90 {
  91         int count, ch, completely_empty = 1, nl_just_seen = 0;
  92         count = 0;
  93         while (0 < size--) {
  94                 ch = *data++;
  95                 if (ch == '\n') {
  96                         count++;
  97                         nl_just_seen = 1;
  98                         completely_empty = 0;
  99                 }
 100                 else {
 101                         nl_just_seen = 0;
 102                         completely_empty = 0;
 103                 }
 104         }
 105         if (completely_empty)
 106                 return 0;
 107         if (!nl_just_seen)
 108                 count++; /* no trailing newline */
 109         return count;
 110 }
 111
 112 static void print_line_count(int count)
 113 {
 114         switch (count) {
 115         case 0:
 116                 printf("0,0");
 117                 break;
 118         case 1:
 119                 printf("1");
 120                 break;
 121         default:
 122                 printf("1,%d", count);
 123                 break;
 124         }
 125 }
 126
 127 static void copy_file(int prefix, const char *data, int size)
 128 {
 129         int ch, nl_just_seen = 1;
 130         while (0 < size--) {
 131                 ch = *data++;
 132                 if (nl_just_seen)
 133                         putchar(prefix);
 134                 putchar(ch);
 135                 if (ch == '\n')
 136                         nl_just_seen = 1;
 137                 else
 138                         nl_just_seen = 0;
 139         }
 140         if (!nl_just_seen)
 141                 printf("\n\\ No newline at end of file\n");
 142 }
 143
 144 static void emit_rewrite_diff(const char *name_a,
 145                               const char *name_b,
 146                               struct diff_filespec *one,
 147                               struct diff_filespec *two)
 148 {
 149         int lc_a, lc_b;
 150         diff_populate_filespec(one, 0);
 151         diff_populate_filespec(two, 0);
 152         lc_a = count_lines(one->data, one->size);
 153         lc_b = count_lines(two->data, two->size);
 154         printf("--- %s\n+++ %s\n@@ -", name_a, name_b);
 155         print_line_count(lc_a);
 156         printf(" +");
 157         print_line_count(lc_b);
 158         printf(" @@\n");
 159         if (lc_a)
 160                 copy_file('-', one->data, one->size);
 161         if (lc_b)
 162                 copy_file('+', two->data, two->size);
 163 }
 164
 165 static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 166 {
 167         if (!DIFF_FILE_VALID(one)) {
 168                 mf->ptr = ""; /* does not matter */
 169                 mf->size = 0;
 170                 return 0;
 171         }
 172         else if (diff_populate_filespec(one, 0))
 173                 return -1;
 174         mf->ptr = one->data;
 175         mf->size = one->size;
 176         return 0;
 177 }
 178
 179 struct emit_callback {
 180         const char **label_path;
 181 };
 182
 183 static int fn_out(void *priv, mmbuffer_t *mb, int nbuf)
 184 {
 185         int i;
 186         struct emit_callback *ecbdata = priv;
 187
 188         if (ecbdata->label_path[0]) {
 189                 printf("--- %s\n", ecbdata->label_path[0]);
 190                 printf("+++ %s\n", ecbdata->label_path[1]);
 191                 ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
 192         }
 193         for (i = 0; i < nbuf; i++)
 194                 if (!fwrite(mb[i].ptr, mb[i].size, 1, stdout))
 195                         return -1;
 196         return 0;
 197 }
 198
 199 static char *pprint_rename(const char *a, const char *b)
 200 {
 201         const char *old = a;
 202         const char *new = b;
 203         char *name = NULL;
 204         int pfx_length, sfx_length;
 205         int len_a = strlen(a);
 206         int len_b = strlen(b);
 207
 208         /* Find common prefix */
 209         pfx_length = 0;
 210         while (*old && *new && *old == *new) {
 211                 if (*old == '/')
 212                         pfx_length = old - a + 1;
 213                 old++;
 214                 new++;
 215         }
 216
 217         /* Find common suffix */
 218         old = a + len_a;
 219         new = b + len_b;
 220         sfx_length = 0;
 221         while (a <= old && b <= new && *old == *new) {
 222                 if (*old == '/')
 223                         sfx_length = len_a - (old - a);
 224                 old--;
 225                 new--;
 226         }
 227
 228         /*
 229          * pfx{mid-a => mid-b}sfx
 230          * {pfx-a => pfx-b}sfx
 231          * pfx{sfx-a => sfx-b}
 232          * name-a => name-b
 233          */
 234         if (pfx_length + sfx_length) {
 235                 int a_midlen = len_a - pfx_length - sfx_length;
 236                 int b_midlen = len_b - pfx_length - sfx_length;
 237                 if (a_midlen < 0) a_midlen = 0;
 238                 if (b_midlen < 0) b_midlen = 0;
 239
 240                 name = xmalloc(len_a + len_b - pfx_length - sfx_length + 7);
 241                 sprintf(name, "%.*s{%.*s => %.*s}%s",
 242                         pfx_length, a,
 243                         a_midlen, a + pfx_length,
 244                         b_midlen, b + pfx_length,
 245                         a + len_a - sfx_length);
 246         }
 247         else {
 248                 name = xmalloc(len_a + len_b + 5);
 249                 sprintf(name, "%s => %s", a, b);
 250         }
 251         return name;
 252 }
 253
 254 struct diffstat_t {
 255         struct xdiff_emit_state xm;
 256
 257         int nr;
 258         int alloc;
 259         struct diffstat_file {
 260                 char *name;
 261                 unsigned is_unmerged:1;
 262                 unsigned is_binary:1;
 263                 unsigned is_renamed:1;
 264                 unsigned int added, deleted;
 265         } **files;
 266 };
 267
 268 static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
 269                                           const char *name_a,
 270                                           const char *name_b)
 271 {
 272         struct diffstat_file *x;
 273         x = xcalloc(sizeof (*x), 1);
 274         if (diffstat->nr == diffstat->alloc) {
 275                 diffstat->alloc = alloc_nr(diffstat->alloc);
 276                 diffstat->files = xrealloc(diffstat->files,
 277                                 diffstat->alloc * sizeof(x));
 278         }
 279         diffstat->files[diffstat->nr++] = x;
 280         if (name_b) {
 281                 x->name = pprint_rename(name_a, name_b);
 282                 x->is_renamed = 1;
 283         }
 284         else
 285                 x->name = strdup(name_a);
 286         return x;
 287 }
 288
 289 static void diffstat_consume(void *priv, char *line, unsigned long len)
 290 {
 291         struct diffstat_t *diffstat = priv;
 292         struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
 293
 294         if (line[0] == '+')
 295                 x->added++;
 296         else if (line[0] == '-')
 297                 x->deleted++;
 298 }
 299
 300 static const char pluses[] = "++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++";
 301 static const char minuses[]= "----------------------------------------------------------------------";
 302
 303 static void show_stats(struct diffstat_t* data)
 304 {
 305         int i, len, add, del, total, adds = 0, dels = 0;
 306         int max, max_change = 0, max_len = 0;
 307         int total_files = data->nr;
 308
 309         if (data->nr == 0)
 310                 return;
 311
 312         for (i = 0; i < data->nr; i++) {
 313                 struct diffstat_file *file = data->files[i];
 314
 315                 len = strlen(file->name);
 316                 if (max_len < len)
 317                         max_len = len;
 318
 319                 if (file->is_binary || file->is_unmerged)
 320                         continue;
 321                 if (max_change < file->added + file->deleted)
 322                         max_change = file->added + file->deleted;
 323         }
 324
 325         for (i = 0; i < data->nr; i++) {
 326                 char *prefix = "";
 327                 char *name = data->files[i]->name;
 328                 int added = data->files[i]->added;
 329                 int deleted = data->files[i]->deleted;
 330
 331                 if (0 < (len = quote_c_style(name, NULL, NULL, 0))) {
 332                         char *qname = xmalloc(len + 1);
 333                         quote_c_style(name, qname, NULL, 0);
 334                         free(name);
 335                         data->files[i]->name = name = qname;
 336                 }
 337
 338                 /*
 339                  * "scale" the filename
 340                  */
 341                 len = strlen(name);
 342                 max = max_len;
 343                 if (max > 50)
 344                         max = 50;
 345                 if (len > max) {
 346                         char *slash;
 347                         prefix = "...";
 348                         max -= 3;
 349                         name += len - max;
 350                         slash = strchr(name, '/');
 351                         if (slash)
 352                                 name = slash;
 353                 }
 354                 len = max;
 355
 356                 /*
 357                  * scale the add/delete
 358                  */
 359                 max = max_change;
 360                 if (max + len > 70)
 361                         max = 70 - len;
 362
 363                 if (data->files[i]->is_binary) {
 364                         printf(" %s%-*s |  Bin\n", prefix, len, name);
 365                         goto free_diffstat_file;
 366                 }
 367                 else if (data->files[i]->is_unmerged) {
 368                         printf(" %s%-*s |  Unmerged\n", prefix, len, name);
 369                         goto free_diffstat_file;
 370                 }
 371                 else if (!data->files[i]->is_renamed &&
 372                          (added + deleted == 0)) {
 373                         total_files--;
 374                         goto free_diffstat_file;
 375                 }
 376
 377                 add = added;
 378                 del = deleted;
 379                 total = add + del;
 380                 adds += add;
 381                 dels += del;
 382
 383                 if (max_change > 0) {
 384                         total = (total * max + max_change / 2) / max_change;
 385                         add = (add * max + max_change / 2) / max_change;
 386                         del = total - add;
 387                 }
 388                 printf(" %s%-*s |%5d %.*s%.*s\n", prefix,
 389                                 len, name, added + deleted,
 390                                 add, pluses, del, minuses);
 391         free_diffstat_file:
 392                 free(data->files[i]->name);
 393                 free(data->files[i]);
 394         }
 395         free(data->files);
 396         printf(" %d files changed, %d insertions(+), %d deletions(-)\n",
 397                         total_files, adds, dels);
 398 }
 399
 400 static unsigned char *deflate_it(char *data,
 401                                  unsigned long size,
 402                                  unsigned long *result_size)
 403 {
 404         int bound;
 405         unsigned char *deflated;
 406         z_stream stream;
 407
 408         memset(&stream, 0, sizeof(stream));
 409         deflateInit(&stream, Z_BEST_COMPRESSION);
 410         bound = deflateBound(&stream, size);
 411         deflated = xmalloc(bound);
 412         stream.next_out = deflated;
 413         stream.avail_out = bound;
 414
 415         stream.next_in = (unsigned char *)data;
 416         stream.avail_in = size;
 417         while (deflate(&stream, Z_FINISH) == Z_OK)
 418                 ; /* nothing */
 419         deflateEnd(&stream);
 420         *result_size = stream.total_out;
 421         return deflated;
 422 }
 423
 424 static void emit_binary_diff(mmfile_t *one, mmfile_t *two)
 425 {
 426         void *cp;
 427         void *delta;
 428         void *deflated;
 429         void *data;
 430         unsigned long orig_size;
 431         unsigned long delta_size;
 432         unsigned long deflate_size;
 433         unsigned long data_size;
 434
 435         printf("GIT binary patch\n");
 436         /* We could do deflated delta, or we could do just deflated two,
 437          * whichever is smaller.
 438          */
 439         delta = NULL;
 440         deflated = deflate_it(two->ptr, two->size, &deflate_size);
 441         if (one->size && two->size) {
 442                 delta = diff_delta(one->ptr, one->size,
 443                                    two->ptr, two->size,
 444                                    &delta_size, deflate_size);
 445                 if (delta) {
 446                         void *to_free = delta;
 447                         orig_size = delta_size;
 448                         delta = deflate_it(delta, delta_size, &delta_size);
 449                         free(to_free);
 450                 }
 451         }
 452
 453         if (delta && delta_size < deflate_size) {
 454                 printf("delta %lu\n", orig_size);
 455                 free(deflated);
 456                 data = delta;
 457                 data_size = delta_size;
 458         }
 459         else {
 460                 printf("literal %lu\n", two->size);
 461                 free(delta);
 462                 data = deflated;
 463                 data_size = deflate_size;
 464         }
 465
 466         /* emit data encoded in base85 */
 467         cp = data;
 468         while (data_size) {
 469                 int bytes = (52 < data_size) ? 52 : data_size;
 470                 char line[70];
 471                 data_size -= bytes;
 472                 if (bytes <= 26)
 473                         line[0] = bytes + 'A' - 1;
 474                 else
 475                         line[0] = bytes - 26 + 'a' - 1;
 476                 encode_85(line + 1, cp, bytes);
 477                 cp += bytes;
 478                 puts(line);
 479         }
 480         printf("\n");
 481         free(data);
 482 }
 483
 484 #define FIRST_FEW_BYTES 8000
 485 static int mmfile_is_binary(mmfile_t *mf)
 486 {
 487         long sz = mf->size;
 488         if (FIRST_FEW_BYTES < sz)
 489                 sz = FIRST_FEW_BYTES;
 490         if (memchr(mf->ptr, 0, sz))
 491                 return 1;
 492         return 0;
 493 }
 494
 495 static void builtin_diff(const char *name_a,
 496                          const char *name_b,
 497                          struct diff_filespec *one,
 498                          struct diff_filespec *two,
 499                          const char *xfrm_msg,
 500                          struct diff_options *o,
 501                          int complete_rewrite)
 502 {
 503         mmfile_t mf1, mf2;
 504         const char *lbl[2];
 505         char *a_one, *b_two;
 506
 507         a_one = quote_two("a/", name_a);
 508         b_two = quote_two("b/", name_b);
 509         lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
 510         lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
 511         printf("diff --git %s %s\n", a_one, b_two);
 512         if (lbl[0][0] == '/') {
 513                 /* /dev/null */
 514                 printf("new file mode %06o\n", two->mode);
 515                 if (xfrm_msg && xfrm_msg[0])
 516                         puts(xfrm_msg);
 517         }
 518         else if (lbl[1][0] == '/') {
 519                 printf("deleted file mode %06o\n", one->mode);
 520                 if (xfrm_msg && xfrm_msg[0])
 521                         puts(xfrm_msg);
 522         }
 523         else {
 524                 if (one->mode != two->mode) {
 525                         printf("old mode %06o\n", one->mode);
 526                         printf("new mode %06o\n", two->mode);
 527                 }
 528                 if (xfrm_msg && xfrm_msg[0])
 529                         puts(xfrm_msg);
 530                 /*
 531                  * we do not run diff between different kind
 532                  * of objects.
 533                  */
 534                 if ((one->mode ^ two->mode) & S_IFMT)
 535                         goto free_ab_and_return;
 536                 if (complete_rewrite) {
 537                         emit_rewrite_diff(name_a, name_b, one, two);
 538                         goto free_ab_and_return;
 539                 }
 540         }
 541
 542         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
 543                 die("unable to read files to diff");
 544
 545         if (mmfile_is_binary(&mf1) || mmfile_is_binary(&mf2)) {
 546                 /* Quite common confusing case */
 547                 if (mf1.size == mf2.size &&
 548                     !memcmp(mf1.ptr, mf2.ptr, mf1.size))
 549                         goto free_ab_and_return;
 550                 if (o->binary)
 551                         emit_binary_diff(&mf1, &mf2);
 552                 else
 553                         printf("Binary files %s and %s differ\n",
 554                                lbl[0], lbl[1]);
 555         }
 556         else {
 557                 /* Crazy xdl interfaces.. */
 558                 const char *diffopts = getenv("GIT_DIFF_OPTS");
 559                 xpparam_t xpp;
 560                 xdemitconf_t xecfg;
 561                 xdemitcb_t ecb;
 562                 struct emit_callback ecbdata;
 563
 564                 ecbdata.label_path = lbl;
 565                 xpp.flags = XDF_NEED_MINIMAL;
 566                 xecfg.ctxlen = 3;
 567                 xecfg.flags = XDL_EMIT_FUNCNAMES;
 568                 if (!diffopts)
 569                         ;
 570                 else if (!strncmp(diffopts, "--unified=", 10))
 571                         xecfg.ctxlen = strtoul(diffopts + 10, NULL, 10);
 572                 else if (!strncmp(diffopts, "-u", 2))
 573                         xecfg.ctxlen = strtoul(diffopts + 2, NULL, 10);
 574                 ecb.outf = fn_out;
 575                 ecb.priv = &ecbdata;
 576                 xdl_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
 577         }
 578
 579  free_ab_and_return:
 580         free(a_one);
 581         free(b_two);
 582         return;
 583 }
 584
 585 static void builtin_diffstat(const char *name_a, const char *name_b,
 586                              struct diff_filespec *one,
 587                              struct diff_filespec *two,
 588                              struct diffstat_t *diffstat,
 589                              int complete_rewrite)
 590 {
 591         mmfile_t mf1, mf2;
 592         struct diffstat_file *data;
 593
 594         data = diffstat_add(diffstat, name_a, name_b);
 595
 596         if (!one || !two) {
 597                 data->is_unmerged = 1;
 598                 return;
 599         }
 600         if (complete_rewrite) {
 601                 diff_populate_filespec(one, 0);
 602                 diff_populate_filespec(two, 0);
 603                 data->deleted = count_lines(one->data, one->size);
 604                 data->added = count_lines(two->data, two->size);
 605                 return;
 606         }
 607         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
 608                 die("unable to read files to diff");
 609
 610         if (mmfile_is_binary(&mf1) || mmfile_is_binary(&mf2))
 611                 data->is_binary = 1;
 612         else {
 613                 /* Crazy xdl interfaces.. */
 614                 xpparam_t xpp;
 615                 xdemitconf_t xecfg;
 616                 xdemitcb_t ecb;
 617
 618                 xpp.flags = XDF_NEED_MINIMAL;
 619                 xecfg.ctxlen = 0;
 620                 xecfg.flags = 0;
 621                 ecb.outf = xdiff_outf;
 622                 ecb.priv = diffstat;
 623                 xdl_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
 624         }
 625 }
 626
 627 struct diff_filespec *alloc_filespec(const char *path)
 628 {
 629         int namelen = strlen(path);
 630         struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
 631
 632         memset(spec, 0, sizeof(*spec));
 633         spec->path = (char *)(spec + 1);
 634         memcpy(spec->path, path, namelen+1);
 635         return spec;
 636 }
 637
 638 void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
 639                    unsigned short mode)
 640 {
 641         if (mode) {
 642                 spec->mode = canon_mode(mode);
 643                 memcpy(spec->sha1, sha1, 20);
 644                 spec->sha1_valid = !!memcmp(sha1, null_sha1, 20);
 645         }
 646 }
 647
 648 /*
 649  * Given a name and sha1 pair, if the dircache tells us the file in
 650  * the work tree has that object contents, return true, so that
 651  * prepare_temp_file() does not have to inflate and extract.
 652  */
 653 static int work_tree_matches(const char *name, const unsigned char *sha1)
 654 {
 655         struct cache_entry *ce;
 656         struct stat st;
 657         int pos, len;
 658
 659         /* We do not read the cache ourselves here, because the
 660          * benchmark with my previous version that always reads cache
 661          * shows that it makes things worse for diff-tree comparing
 662          * two linux-2.6 kernel trees in an already checked out work
 663          * tree.  This is because most diff-tree comparisons deal with
 664          * only a small number of files, while reading the cache is
 665          * expensive for a large project, and its cost outweighs the
 666          * savings we get by not inflating the object to a temporary
 667          * file.  Practically, this code only helps when we are used
 668          * by diff-cache --cached, which does read the cache before
 669          * calling us.
 670          */
 671         if (!active_cache)
 672                 return 0;
 673
 674         len = strlen(name);
 675         pos = cache_name_pos(name, len);
 676         if (pos < 0)
 677                 return 0;
 678         ce = active_cache[pos];
 679         if ((lstat(name, &st) < 0) ||
 680             !S_ISREG(st.st_mode) || /* careful! */
 681             ce_match_stat(ce, &st, 0) ||
 682             memcmp(sha1, ce->sha1, 20))
 683                 return 0;
 684         /* we return 1 only when we can stat, it is a regular file,
 685          * stat information matches, and sha1 recorded in the cache
 686          * matches.  I.e. we know the file in the work tree really is
 687          * the same as the <name, sha1> pair.
 688          */
 689         return 1;
 690 }
 691
 692 static struct sha1_size_cache {
 693         unsigned char sha1[20];
 694         unsigned long size;
 695 } **sha1_size_cache;
 696 static int sha1_size_cache_nr, sha1_size_cache_alloc;
 697
 698 static struct sha1_size_cache *locate_size_cache(unsigned char *sha1,
 699                                                  int find_only,
 700                                                  unsigned long size)
 701 {
 702         int first, last;
 703         struct sha1_size_cache *e;
 704
 705         first = 0;
 706         last = sha1_size_cache_nr;
 707         while (last > first) {
 708                 int cmp, next = (last + first) >> 1;
 709                 e = sha1_size_cache[next];
 710                 cmp = memcmp(e->sha1, sha1, 20);
 711                 if (!cmp)
 712                         return e;
 713                 if (cmp < 0) {
 714                         last = next;
 715                         continue;
 716                 }
 717                 first = next+1;
 718         }
 719         /* not found */
 720         if (find_only)
 721                 return NULL;
 722         /* insert to make it at "first" */
 723         if (sha1_size_cache_alloc <= sha1_size_cache_nr) {
 724                 sha1_size_cache_alloc = alloc_nr(sha1_size_cache_alloc);
 725                 sha1_size_cache = xrealloc(sha1_size_cache,
 726                                            sha1_size_cache_alloc *
 727                                            sizeof(*sha1_size_cache));
 728         }
 729         sha1_size_cache_nr++;
 730         if (first < sha1_size_cache_nr)
 731                 memmove(sha1_size_cache + first + 1, sha1_size_cache + first,
 732                         (sha1_size_cache_nr - first - 1) *
 733                         sizeof(*sha1_size_cache));
 734         e = xmalloc(sizeof(struct sha1_size_cache));
 735         sha1_size_cache[first] = e;
 736         memcpy(e->sha1, sha1, 20);
 737         e->size = size;
 738         return e;
 739 }
 740
 741 /*
 742  * While doing rename detection and pickaxe operation, we may need to
 743  * grab the data for the blob (or file) for our own in-core comparison.
 744  * diff_filespec has data and size fields for this purpose.
 745  */
 746 int diff_populate_filespec(struct diff_filespec *s, int size_only)
 747 {
 748         int err = 0;
 749         if (!DIFF_FILE_VALID(s))
 750                 die("internal error: asking to populate invalid file.");
 751         if (S_ISDIR(s->mode))
 752                 return -1;
 753
 754         if (!use_size_cache)
 755                 size_only = 0;
 756
 757         if (s->data)
 758                 return err;
 759         if (!s->sha1_valid ||
 760             work_tree_matches(s->path, s->sha1)) {
 761                 struct stat st;
 762                 int fd;
 763                 if (lstat(s->path, &st) < 0) {
 764                         if (errno == ENOENT) {
 765                         err_empty:
 766                                 err = -1;
 767                         empty:
 768                                 s->data = "";
 769                                 s->size = 0;
 770                                 return err;
 771                         }
 772                 }
 773                 s->size = st.st_size;
 774                 if (!s->size)
 775                         goto empty;
 776                 if (size_only)
 777                         return 0;
 778                 if (S_ISLNK(st.st_mode)) {
 779                         int ret;
 780                         s->data = xmalloc(s->size);
 781                         s->should_free = 1;
 782                         ret = readlink(s->path, s->data, s->size);
 783                         if (ret < 0) {
 784                                 free(s->data);
 785                                 goto err_empty;
 786                         }
 787                         return 0;
 788                 }
 789                 fd = open(s->path, O_RDONLY);
 790                 if (fd < 0)
 791                         goto err_empty;
 792                 s->data = mmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
 793                 close(fd);
 794                 if (s->data == MAP_FAILED)
 795                         goto err_empty;
 796                 s->should_munmap = 1;
 797         }
 798         else {
 799                 char type[20];
 800                 struct sha1_size_cache *e;
 801
 802                 if (size_only) {
 803                         e = locate_size_cache(s->sha1, 1, 0);
 804                         if (e) {
 805                                 s->size = e->size;
 806                                 return 0;
 807                         }
 808                         if (!sha1_object_info(s->sha1, type, &s->size))
 809                                 locate_size_cache(s->sha1, 0, s->size);
 810                 }
 811                 else {
 812                         s->data = read_sha1_file(s->sha1, type, &s->size);
 813                         s->should_free = 1;
 814                 }
 815         }
 816         return 0;
 817 }
 818
 819 void diff_free_filespec_data(struct diff_filespec *s)
 820 {
 821         if (s->should_free)
 822                 free(s->data);
 823         else if (s->should_munmap)
 824                 munmap(s->data, s->size);
 825         s->should_free = s->should_munmap = 0;
 826         s->data = NULL;
 827         free(s->cnt_data);
 828         s->cnt_data = NULL;
 829 }
 830
 831 static void prep_temp_blob(struct diff_tempfile *temp,
 832                            void *blob,
 833                            unsigned long size,
 834                            const unsigned char *sha1,
 835                            int mode)
 836 {
 837         int fd;
 838
 839         fd = git_mkstemp(temp->tmp_path, TEMPFILE_PATH_LEN, ".diff_XXXXXX");
 840         if (fd < 0)
 841                 die("unable to create temp-file");
 842         if (write(fd, blob, size) != size)
 843                 die("unable to write temp-file");
 844         close(fd);
 845         temp->name = temp->tmp_path;
 846         strcpy(temp->hex, sha1_to_hex(sha1));
 847         temp->hex[40] = 0;
 848         sprintf(temp->mode, "%06o", mode);
 849 }
 850
 851 static void prepare_temp_file(const char *name,
 852                               struct diff_tempfile *temp,
 853                               struct diff_filespec *one)
 854 {
 855         if (!DIFF_FILE_VALID(one)) {
 856         not_a_valid_file:
 857                 /* A '-' entry produces this for file-2, and
 858                  * a '+' entry produces this for file-1.
 859                  */
 860                 temp->name = "/dev/null";
 861                 strcpy(temp->hex, ".");
 862                 strcpy(temp->mode, ".");
 863                 return;
 864         }
 865
 866         if (!one->sha1_valid ||
 867             work_tree_matches(name, one->sha1)) {
 868                 struct stat st;
 869                 if (lstat(name, &st) < 0) {
 870                         if (errno == ENOENT)
 871                                 goto not_a_valid_file;
 872                         die("stat(%s): %s", name, strerror(errno));
 873                 }
 874                 if (S_ISLNK(st.st_mode)) {
 875                         int ret;
 876                         char buf[PATH_MAX + 1]; /* ought to be SYMLINK_MAX */
 877                         if (sizeof(buf) <= st.st_size)
 878                                 die("symlink too long: %s", name);
 879                         ret = readlink(name, buf, st.st_size);
 880                         if (ret < 0)
 881                                 die("readlink(%s)", name);
 882                         prep_temp_blob(temp, buf, st.st_size,
 883                                        (one->sha1_valid ?
 884                                         one->sha1 : null_sha1),
 885                                        (one->sha1_valid ?
 886                                         one->mode : S_IFLNK));
 887                 }
 888                 else {
 889                         /* we can borrow from the file in the work tree */
 890                         temp->name = name;
 891                         if (!one->sha1_valid)
 892                                 strcpy(temp->hex, sha1_to_hex(null_sha1));
 893                         else
 894                                 strcpy(temp->hex, sha1_to_hex(one->sha1));
 895                         /* Even though we may sometimes borrow the
 896                          * contents from the work tree, we always want
 897                          * one->mode.  mode is trustworthy even when
 898                          * !(one->sha1_valid), as long as
 899                          * DIFF_FILE_VALID(one).
 900                          */
 901                         sprintf(temp->mode, "%06o", one->mode);
 902                 }
 903                 return;
 904         }
 905         else {
 906                 if (diff_populate_filespec(one, 0))
 907                         die("cannot read data blob for %s", one->path);
 908                 prep_temp_blob(temp, one->data, one->size,
 909                                one->sha1, one->mode);
 910         }
 911 }
 912
 913 static void remove_tempfile(void)
 914 {
 915         int i;
 916
 917         for (i = 0; i < 2; i++)
 918                 if (diff_temp[i].name == diff_temp[i].tmp_path) {
 919                         unlink(diff_temp[i].name);
 920                         diff_temp[i].name = NULL;
 921                 }
 922 }
 923
 924 static void remove_tempfile_on_signal(int signo)
 925 {
 926         remove_tempfile();
 927         signal(SIGINT, SIG_DFL);
 928         raise(signo);
 929 }
 930
 931 static int spawn_prog(const char *pgm, const char **arg)
 932 {
 933         pid_t pid;
 934         int status;
 935
 936         fflush(NULL);
 937         pid = fork();
 938         if (pid < 0)
 939                 die("unable to fork");
 940         if (!pid) {
 941                 execvp(pgm, (char *const*) arg);
 942                 exit(255);
 943         }
 944
 945         while (waitpid(pid, &status, 0) < 0) {
 946                 if (errno == EINTR)
 947                         continue;
 948                 return -1;
 949         }
 950
 951         /* Earlier we did not check the exit status because
 952          * diff exits non-zero if files are different, and
 953          * we are not interested in knowing that.  It was a
 954          * mistake which made it harder to quit a diff-*
 955          * session that uses the git-apply-patch-script as
 956          * the GIT_EXTERNAL_DIFF.  A custom GIT_EXTERNAL_DIFF
 957          * should also exit non-zero only when it wants to
 958          * abort the entire diff-* session.
 959          */
 960         if (WIFEXITED(status) && !WEXITSTATUS(status))
 961                 return 0;
 962         return -1;
 963 }
 964
 965 /* An external diff command takes:
 966  *
 967  * diff-cmd name infile1 infile1-sha1 infile1-mode \
 968  *               infile2 infile2-sha1 infile2-mode [ rename-to ]
 969  *
 970  */
 971 static void run_external_diff(const char *pgm,
 972                               const char *name,
 973                               const char *other,
 974                               struct diff_filespec *one,
 975                               struct diff_filespec *two,
 976                               const char *xfrm_msg,
 977                               int complete_rewrite)
 978 {
 979         const char *spawn_arg[10];
 980         struct diff_tempfile *temp = diff_temp;
 981         int retval;
 982         static int atexit_asked = 0;
 983         const char *othername;
 984         const char **arg = &spawn_arg[0];
 985
 986         othername = (other? other : name);
 987         if (one && two) {
 988                 prepare_temp_file(name, &temp[0], one);
 989                 prepare_temp_file(othername, &temp[1], two);
 990                 if (! atexit_asked &&
 991                     (temp[0].name == temp[0].tmp_path ||
 992                      temp[1].name == temp[1].tmp_path)) {
 993                         atexit_asked = 1;
 994                         atexit(remove_tempfile);
 995                 }
 996                 signal(SIGINT, remove_tempfile_on_signal);
 997         }
 998
 999         if (one && two) {
1000                 *arg++ = pgm;
1001                 *arg++ = name;
1002                 *arg++ = temp[0].name;
1003                 *arg++ = temp[0].hex;
1004                 *arg++ = temp[0].mode;
1005                 *arg++ = temp[1].name;
1006                 *arg++ = temp[1].hex;
1007                 *arg++ = temp[1].mode;
1008                 if (other) {
1009                         *arg++ = other;
1010                         *arg++ = xfrm_msg;
1011                 }
1012         } else {
1013                 *arg++ = pgm;
1014                 *arg++ = name;
1015         }
1016         *arg = NULL;
1017         retval = spawn_prog(pgm, spawn_arg);
1018         remove_tempfile();
1019         if (retval) {
1020                 fprintf(stderr, "external diff died, stopping at %s.\n", name);
1021                 exit(1);
1022         }
1023 }
1024
1025 static void run_diff_cmd(const char *pgm,
1026                          const char *name,
1027                          const char *other,
1028                          struct diff_filespec *one,
1029                          struct diff_filespec *two,
1030                          const char *xfrm_msg,
1031                          struct diff_options *o,
1032                          int complete_rewrite)
1033 {
1034         if (pgm) {
1035                 run_external_diff(pgm, name, other, one, two, xfrm_msg,
1036                                   complete_rewrite);
1037                 return;
1038         }
1039         if (one && two)
1040                 builtin_diff(name, other ? other : name,
1041                              one, two, xfrm_msg, o, complete_rewrite);
1042         else
1043                 printf("* Unmerged path %s\n", name);
1044 }
1045
1046 static void diff_fill_sha1_info(struct diff_filespec *one)
1047 {
1048         if (DIFF_FILE_VALID(one)) {
1049                 if (!one->sha1_valid) {
1050                         struct stat st;
1051                         if (lstat(one->path, &st) < 0)
1052                                 die("stat %s", one->path);
1053                         if (index_path(one->sha1, one->path, &st, 0))
1054                                 die("cannot hash %s\n", one->path);
1055                 }
1056         }
1057         else
1058                 memset(one->sha1, 0, 20);
1059 }
1060
1061 static void run_diff(struct diff_filepair *p, struct diff_options *o)
1062 {
1063         const char *pgm = external_diff();
1064         char msg[PATH_MAX*2+300], *xfrm_msg;
1065         struct diff_filespec *one;
1066         struct diff_filespec *two;
1067         const char *name;
1068         const char *other;
1069         char *name_munged, *other_munged;
1070         int complete_rewrite = 0;
1071         int len;
1072
1073         if (DIFF_PAIR_UNMERGED(p)) {
1074                 /* unmerged */
1075                 run_diff_cmd(pgm, p->one->path, NULL, NULL, NULL, NULL, o, 0);
1076                 return;
1077         }
1078
1079         name = p->one->path;
1080         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
1081         name_munged = quote_one(name);
1082         other_munged = quote_one(other);
1083         one = p->one; two = p->two;
1084
1085         diff_fill_sha1_info(one);
1086         diff_fill_sha1_info(two);
1087
1088         len = 0;
1089         switch (p->status) {
1090         case DIFF_STATUS_COPIED:
1091                 len += snprintf(msg + len, sizeof(msg) - len,
1092                                 "similarity index %d%%\n"
1093                                 "copy from %s\n"
1094                                 "copy to %s\n",
1095                                 (int)(0.5 + p->score * 100.0/MAX_SCORE),
1096                                 name_munged, other_munged);
1097                 break;
1098         case DIFF_STATUS_RENAMED:
1099                 len += snprintf(msg + len, sizeof(msg) - len,
1100                                 "similarity index %d%%\n"
1101                                 "rename from %s\n"
1102                                 "rename to %s\n",
1103                                 (int)(0.5 + p->score * 100.0/MAX_SCORE),
1104                                 name_munged, other_munged);
1105                 break;
1106         case DIFF_STATUS_MODIFIED:
1107                 if (p->score) {
1108                         len += snprintf(msg + len, sizeof(msg) - len,
1109                                         "dissimilarity index %d%%\n",
1110                                         (int)(0.5 + p->score *
1111                                               100.0/MAX_SCORE));
1112                         complete_rewrite = 1;
1113                         break;
1114                 }
1115                 /* fallthru */
1116         default:
1117                 /* nothing */
1118                 ;
1119         }
1120
1121         if (memcmp(one->sha1, two->sha1, 20)) {
1122                 int abbrev = o->full_index ? 40 : DEFAULT_ABBREV;
1123
1124                 len += snprintf(msg + len, sizeof(msg) - len,
1125                                 "index %.*s..%.*s",
1126                                 abbrev, sha1_to_hex(one->sha1),
1127                                 abbrev, sha1_to_hex(two->sha1));
1128                 if (one->mode == two->mode)
1129                         len += snprintf(msg + len, sizeof(msg) - len,
1130                                         " %06o", one->mode);
1131                 len += snprintf(msg + len, sizeof(msg) - len, "\n");
1132         }
1133
1134         if (len)
1135                 msg[--len] = 0;
1136         xfrm_msg = len ? msg : NULL;
1137
1138         if (!pgm &&
1139             DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
1140             (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
1141                 /* a filepair that changes between file and symlink
1142                  * needs to be split into deletion and creation.
1143                  */
1144                 struct diff_filespec *null = alloc_filespec(two->path);
1145                 run_diff_cmd(NULL, name, other, one, null, xfrm_msg, o, 0);
1146                 free(null);
1147                 null = alloc_filespec(one->path);
1148                 run_diff_cmd(NULL, name, other, null, two, xfrm_msg, o, 0);
1149                 free(null);
1150         }
1151         else
1152                 run_diff_cmd(pgm, name, other, one, two, xfrm_msg, o,
1153                              complete_rewrite);
1154
1155         free(name_munged);
1156         free(other_munged);
1157 }
1158
1159 static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
1160                          struct diffstat_t *diffstat)
1161 {
1162         const char *name;
1163         const char *other;
1164         int complete_rewrite = 0;
1165
1166         if (DIFF_PAIR_UNMERGED(p)) {
1167                 /* unmerged */
1168                 builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, 0);
1169                 return;
1170         }
1171
1172         name = p->one->path;
1173         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
1174
1175         diff_fill_sha1_info(p->one);
1176         diff_fill_sha1_info(p->two);
1177
1178         if (p->status == DIFF_STATUS_MODIFIED && p->score)
1179                 complete_rewrite = 1;
1180         builtin_diffstat(name, other, p->one, p->two, diffstat, complete_rewrite);
1181 }
1182
1183 void diff_setup(struct diff_options *options)
1184 {
1185         memset(options, 0, sizeof(*options));
1186         options->output_format = DIFF_FORMAT_RAW;
1187         options->line_termination = '\n';
1188         options->break_opt = -1;
1189         options->rename_limit = -1;
1190
1191         options->change = diff_change;
1192         options->add_remove = diff_addremove;
1193 }
1194
1195 int diff_setup_done(struct diff_options *options)
1196 {
1197         if ((options->find_copies_harder &&
1198              options->detect_rename != DIFF_DETECT_COPY) ||
1199             (0 <= options->rename_limit && !options->detect_rename))
1200                 return -1;
1201
1202         /*
1203          * These cases always need recursive; we do not drop caller-supplied
1204          * recursive bits for other formats here.
1205          */
1206         if ((options->output_format == DIFF_FORMAT_PATCH) ||
1207             (options->output_format == DIFF_FORMAT_DIFFSTAT))
1208                 options->recursive = 1;
1209
1210         if (options->detect_rename && options->rename_limit < 0)
1211                 options->rename_limit = diff_rename_limit_default;
1212         if (options->setup & DIFF_SETUP_USE_CACHE) {
1213                 if (!active_cache)
1214                         /* read-cache does not die even when it fails
1215                          * so it is safe for us to do this here.  Also
1216                          * it does not smudge active_cache or active_nr
1217                          * when it fails, so we do not have to worry about
1218                          * cleaning it up ourselves either.
1219                          */
1220                         read_cache();
1221         }
1222         if (options->setup & DIFF_SETUP_USE_SIZE_CACHE)
1223                 use_size_cache = 1;
1224         if (options->abbrev <= 0 || 40 < options->abbrev)
1225                 options->abbrev = 40; /* full */
1226
1227         return 0;
1228 }
1229
1230 int diff_opt_parse(struct diff_options *options, const char **av, int ac)
1231 {
1232         const char *arg = av[0];
1233         if (!strcmp(arg, "-p") || !strcmp(arg, "-u"))
1234                 options->output_format = DIFF_FORMAT_PATCH;
1235         else if (!strcmp(arg, "--patch-with-raw")) {
1236                 options->output_format = DIFF_FORMAT_PATCH;
1237                 options->with_raw = 1;
1238         }
1239         else if (!strcmp(arg, "--stat"))
1240                 options->output_format = DIFF_FORMAT_DIFFSTAT;
1241         else if (!strcmp(arg, "--patch-with-stat")) {
1242                 options->output_format = DIFF_FORMAT_PATCH;
1243                 options->with_stat = 1;
1244         }
1245         else if (!strcmp(arg, "-z"))
1246                 options->line_termination = 0;
1247         else if (!strncmp(arg, "-l", 2))
1248                 options->rename_limit = strtoul(arg+2, NULL, 10);
1249         else if (!strcmp(arg, "--full-index"))
1250                 options->full_index = 1;
1251         else if (!strcmp(arg, "--binary")) {
1252                 options->output_format = DIFF_FORMAT_PATCH;
1253                 options->full_index = options->binary = 1;
1254         }
1255         else if (!strcmp(arg, "--name-only"))
1256                 options->output_format = DIFF_FORMAT_NAME;
1257         else if (!strcmp(arg, "--name-status"))
1258                 options->output_format = DIFF_FORMAT_NAME_STATUS;
1259         else if (!strcmp(arg, "-R"))
1260                 options->reverse_diff = 1;
1261         else if (!strncmp(arg, "-S", 2))
1262                 options->pickaxe = arg + 2;
1263         else if (!strcmp(arg, "-s"))
1264                 options->output_format = DIFF_FORMAT_NO_OUTPUT;
1265         else if (!strncmp(arg, "-O", 2))
1266                 options->orderfile = arg + 2;
1267         else if (!strncmp(arg, "--diff-filter=", 14))
1268                 options->filter = arg + 14;
1269         else if (!strcmp(arg, "--pickaxe-all"))
1270                 options->pickaxe_opts = DIFF_PICKAXE_ALL;
1271         else if (!strcmp(arg, "--pickaxe-regex"))
1272                 options->pickaxe_opts = DIFF_PICKAXE_REGEX;
1273         else if (!strncmp(arg, "-B", 2)) {
1274                 if ((options->break_opt =
1275                      diff_scoreopt_parse(arg)) == -1)
1276                         return -1;
1277         }
1278         else if (!strncmp(arg, "-M", 2)) {
1279                 if ((options->rename_score =
1280                      diff_scoreopt_parse(arg)) == -1)
1281                         return -1;
1282                 options->detect_rename = DIFF_DETECT_RENAME;
1283         }
1284         else if (!strncmp(arg, "-C", 2)) {
1285                 if ((options->rename_score =
1286                      diff_scoreopt_parse(arg)) == -1)
1287                         return -1;
1288                 options->detect_rename = DIFF_DETECT_COPY;
1289         }
1290         else if (!strcmp(arg, "--find-copies-harder"))
1291                 options->find_copies_harder = 1;
1292         else if (!strcmp(arg, "--abbrev"))
1293                 options->abbrev = DEFAULT_ABBREV;
1294         else if (!strncmp(arg, "--abbrev=", 9)) {
1295                 options->abbrev = strtoul(arg + 9, NULL, 10);
1296                 if (options->abbrev < MINIMUM_ABBREV)
1297                         options->abbrev = MINIMUM_ABBREV;
1298                 else if (40 < options->abbrev)
1299                         options->abbrev = 40;
1300         }
1301         else
1302                 return 0;
1303         return 1;
1304 }
1305
1306 static int parse_num(const char **cp_p)
1307 {
1308         unsigned long num, scale;
1309         int ch, dot;
1310         const char *cp = *cp_p;
1311
1312         num = 0;
1313         scale = 1;
1314         dot = 0;
1315         for(;;) {
1316                 ch = *cp;
1317                 if ( !dot && ch == '.' ) {
1318                         scale = 1;
1319                         dot = 1;
1320                 } else if ( ch == '%' ) {
1321                         scale = dot ? scale*100 : 100;
1322                         cp++;   /* % is always at the end */
1323                         break;
1324                 } else if ( ch >= '0' && ch <= '9' ) {
1325                         if ( scale < 100000 ) {
1326                                 scale *= 10;
1327                                 num = (num*10) + (ch-'0');
1328                         }
1329                 } else {
1330                         break;
1331                 }
1332                 cp++;
1333         }
1334         *cp_p = cp;
1335
1336         /* user says num divided by scale and we say internally that
1337          * is MAX_SCORE * num / scale.
1338          */
1339         return (num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale);
1340 }
1341
1342 int diff_scoreopt_parse(const char *opt)
1343 {
1344         int opt1, opt2, cmd;
1345
1346         if (*opt++ != '-')
1347                 return -1;
1348         cmd = *opt++;
1349         if (cmd != 'M' && cmd != 'C' && cmd != 'B')
1350                 return -1; /* that is not a -M, -C nor -B option */
1351
1352         opt1 = parse_num(&opt);
1353         if (cmd != 'B')
1354                 opt2 = 0;
1355         else {
1356                 if (*opt == 0)
1357                         opt2 = 0;
1358                 else if (*opt != '/')
1359                         return -1; /* we expect -B80/99 or -B80 */
1360                 else {
1361                         opt++;
1362                         opt2 = parse_num(&opt);
1363                 }
1364         }
1365         if (*opt != 0)
1366                 return -1;
1367         return opt1 | (opt2 << 16);
1368 }
1369
1370 struct diff_queue_struct diff_queued_diff;
1371
1372 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
1373 {
1374         if (queue->alloc <= queue->nr) {
1375                 queue->alloc = alloc_nr(queue->alloc);
1376                 queue->queue = xrealloc(queue->queue,
1377                                         sizeof(dp) * queue->alloc);
1378         }
1379         queue->queue[queue->nr++] = dp;
1380 }
1381
1382 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
1383                                  struct diff_filespec *one,
1384                                  struct diff_filespec *two)
1385 {
1386         struct diff_filepair *dp = xmalloc(sizeof(*dp));
1387         dp->one = one;
1388         dp->two = two;
1389         dp->score = 0;
1390         dp->status = 0;
1391         dp->source_stays = 0;
1392         dp->broken_pair = 0;
1393         if (queue)
1394                 diff_q(queue, dp);
1395         return dp;
1396 }
1397
1398 void diff_free_filepair(struct diff_filepair *p)
1399 {
1400         diff_free_filespec_data(p->one);
1401         diff_free_filespec_data(p->two);
1402         free(p->one);
1403         free(p->two);
1404         free(p);
1405 }
1406
1407 /* This is different from find_unique_abbrev() in that
1408  * it stuffs the result with dots for alignment.
1409  */
1410 const char *diff_unique_abbrev(const unsigned char *sha1, int len)
1411 {
1412         int abblen;
1413         const char *abbrev;
1414         if (len == 40)
1415                 return sha1_to_hex(sha1);
1416
1417         abbrev = find_unique_abbrev(sha1, len);
1418         if (!abbrev)
1419                 return sha1_to_hex(sha1);
1420         abblen = strlen(abbrev);
1421         if (abblen < 37) {
1422                 static char hex[41];
1423                 if (len < abblen && abblen <= len + 2)
1424                         sprintf(hex, "%s%.*s", abbrev, len+3-abblen, "..");
1425                 else
1426                         sprintf(hex, "%s...", abbrev);
1427                 return hex;
1428         }
1429         return sha1_to_hex(sha1);
1430 }
1431
1432 static void diff_flush_raw(struct diff_filepair *p,
1433                            int line_termination,
1434                            int inter_name_termination,
1435                            struct diff_options *options,
1436                            int output_format)
1437 {
1438         int two_paths;
1439         char status[10];
1440         int abbrev = options->abbrev;
1441         const char *path_one, *path_two;
1442
1443         path_one = p->one->path;
1444         path_two = p->two->path;
1445         if (line_termination) {
1446                 path_one = quote_one(path_one);
1447                 path_two = quote_one(path_two);
1448         }
1449
1450         if (p->score)
1451                 sprintf(status, "%c%03d", p->status,
1452                         (int)(0.5 + p->score * 100.0/MAX_SCORE));
1453         else {
1454                 status[0] = p->status;
1455                 status[1] = 0;
1456         }
1457         switch (p->status) {
1458         case DIFF_STATUS_COPIED:
1459         case DIFF_STATUS_RENAMED:
1460                 two_paths = 1;
1461                 break;
1462         case DIFF_STATUS_ADDED:
1463         case DIFF_STATUS_DELETED:
1464                 two_paths = 0;
1465                 break;
1466         default:
1467                 two_paths = 0;
1468                 break;
1469         }
1470         if (output_format != DIFF_FORMAT_NAME_STATUS) {
1471                 printf(":%06o %06o %s ",
1472                        p->one->mode, p->two->mode,
1473                        diff_unique_abbrev(p->one->sha1, abbrev));
1474                 printf("%s ",
1475                        diff_unique_abbrev(p->two->sha1, abbrev));
1476         }
1477         printf("%s%c%s", status, inter_name_termination, path_one);
1478         if (two_paths)
1479                 printf("%c%s", inter_name_termination, path_two);
1480         putchar(line_termination);
1481         if (path_one != p->one->path)
1482                 free((void*)path_one);
1483         if (path_two != p->two->path)
1484                 free((void*)path_two);
1485 }
1486
1487 static void diff_flush_name(struct diff_filepair *p,
1488                             int inter_name_termination,
1489                             int line_termination)
1490 {
1491         char *path = p->two->path;
1492
1493         if (line_termination)
1494                 path = quote_one(p->two->path);
1495         else
1496                 path = p->two->path;
1497         printf("%s%c", path, line_termination);
1498         if (p->two->path != path)
1499                 free(path);
1500 }
1501
1502 int diff_unmodified_pair(struct diff_filepair *p)
1503 {
1504         /* This function is written stricter than necessary to support
1505          * the currently implemented transformers, but the idea is to
1506          * let transformers to produce diff_filepairs any way they want,
1507          * and filter and clean them up here before producing the output.
1508          */
1509         struct diff_filespec *one, *two;
1510
1511         if (DIFF_PAIR_UNMERGED(p))
1512                 return 0; /* unmerged is interesting */
1513
1514         one = p->one;
1515         two = p->two;
1516
1517         /* deletion, addition, mode or type change
1518          * and rename are all interesting.
1519          */
1520         if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
1521             DIFF_PAIR_MODE_CHANGED(p) ||
1522             strcmp(one->path, two->path))
1523                 return 0;
1524
1525         /* both are valid and point at the same path.  that is, we are
1526          * dealing with a change.
1527          */
1528         if (one->sha1_valid && two->sha1_valid &&
1529             !memcmp(one->sha1, two->sha1, sizeof(one->sha1)))
1530                 return 1; /* no change */
1531         if (!one->sha1_valid && !two->sha1_valid)
1532                 return 1; /* both look at the same file on the filesystem. */
1533         return 0;
1534 }
1535
1536 static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
1537 {
1538         if (diff_unmodified_pair(p))
1539                 return;
1540
1541         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
1542             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
1543                 return; /* no tree diffs in patch format */
1544
1545         run_diff(p, o);
1546 }
1547
1548 static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
1549                             struct diffstat_t *diffstat)
1550 {
1551         if (diff_unmodified_pair(p))
1552                 return;
1553
1554         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
1555             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
1556                 return; /* no tree diffs in patch format */
1557
1558         run_diffstat(p, o, diffstat);
1559 }
1560
1561 int diff_queue_is_empty(void)
1562 {
1563         struct diff_queue_struct *q = &diff_queued_diff;
1564         int i;
1565         for (i = 0; i < q->nr; i++)
1566                 if (!diff_unmodified_pair(q->queue[i]))
1567                         return 0;
1568         return 1;
1569 }
1570
1571 #if DIFF_DEBUG
1572 void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
1573 {
1574         fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
1575                 x, one ? one : "",
1576                 s->path,
1577                 DIFF_FILE_VALID(s) ? "valid" : "invalid",
1578                 s->mode,
1579                 s->sha1_valid ? sha1_to_hex(s->sha1) : "");
1580         fprintf(stderr, "queue[%d] %s size %lu flags %d\n",
1581                 x, one ? one : "",
1582                 s->size, s->xfrm_flags);
1583 }
1584
1585 void diff_debug_filepair(const struct diff_filepair *p, int i)
1586 {
1587         diff_debug_filespec(p->one, i, "one");
1588         diff_debug_filespec(p->two, i, "two");
1589         fprintf(stderr, "score %d, status %c stays %d broken %d\n",
1590                 p->score, p->status ? p->status : '?',
1591                 p->source_stays, p->broken_pair);
1592 }
1593
1594 void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
1595 {
1596         int i;
1597         if (msg)
1598                 fprintf(stderr, "%s\n", msg);
1599         fprintf(stderr, "q->nr = %d\n", q->nr);
1600         for (i = 0; i < q->nr; i++) {
1601                 struct diff_filepair *p = q->queue[i];
1602                 diff_debug_filepair(p, i);
1603         }
1604 }
1605 #endif
1606
1607 static void diff_resolve_rename_copy(void)
1608 {
1609         int i, j;
1610         struct diff_filepair *p, *pp;
1611         struct diff_queue_struct *q = &diff_queued_diff;
1612
1613         diff_debug_queue("resolve-rename-copy", q);
1614
1615         for (i = 0; i < q->nr; i++) {
1616                 p = q->queue[i];
1617                 p->status = 0; /* undecided */
1618                 if (DIFF_PAIR_UNMERGED(p))
1619                         p->status = DIFF_STATUS_UNMERGED;
1620                 else if (!DIFF_FILE_VALID(p->one))
1621                         p->status = DIFF_STATUS_ADDED;
1622                 else if (!DIFF_FILE_VALID(p->two))
1623                         p->status = DIFF_STATUS_DELETED;
1624                 else if (DIFF_PAIR_TYPE_CHANGED(p))
1625                         p->status = DIFF_STATUS_TYPE_CHANGED;
1626
1627                 /* from this point on, we are dealing with a pair
1628                  * whose both sides are valid and of the same type, i.e.
1629                  * either in-place edit or rename/copy edit.
1630                  */
1631                 else if (DIFF_PAIR_RENAME(p)) {
1632                         if (p->source_stays) {
1633                                 p->status = DIFF_STATUS_COPIED;
1634                                 continue;
1635                         }
1636                         /* See if there is some other filepair that
1637                          * copies from the same source as us.  If so
1638                          * we are a copy.  Otherwise we are either a
1639                          * copy if the path stays, or a rename if it
1640                          * does not, but we already handled "stays" case.
1641                          */
1642                         for (j = i + 1; j < q->nr; j++) {
1643                                 pp = q->queue[j];
1644                                 if (strcmp(pp->one->path, p->one->path))
1645                                         continue; /* not us */
1646                                 if (!DIFF_PAIR_RENAME(pp))
1647                                         continue; /* not a rename/copy */
1648                                 /* pp is a rename/copy from the same source */
1649                                 p->status = DIFF_STATUS_COPIED;
1650                                 break;
1651                         }
1652                         if (!p->status)
1653                                 p->status = DIFF_STATUS_RENAMED;
1654                 }
1655                 else if (memcmp(p->one->sha1, p->two->sha1, 20) ||
1656                          p->one->mode != p->two->mode)
1657                         p->status = DIFF_STATUS_MODIFIED;
1658                 else {
1659                         /* This is a "no-change" entry and should not
1660                          * happen anymore, but prepare for broken callers.
1661                          */
1662                         error("feeding unmodified %s to diffcore",
1663                               p->one->path);
1664                         p->status = DIFF_STATUS_UNKNOWN;
1665                 }
1666         }
1667         diff_debug_queue("resolve-rename-copy done", q);
1668 }
1669
1670 static void flush_one_pair(struct diff_filepair *p,
1671                            int diff_output_format,
1672                            struct diff_options *options,
1673                            struct diffstat_t *diffstat)
1674 {
1675         int inter_name_termination = '\t';
1676         int line_termination = options->line_termination;
1677         if (!line_termination)
1678                 inter_name_termination = 0;
1679
1680         switch (p->status) {
1681         case DIFF_STATUS_UNKNOWN:
1682                 break;
1683         case 0:
1684                 die("internal error in diff-resolve-rename-copy");
1685                 break;
1686         default:
1687                 switch (diff_output_format) {
1688                 case DIFF_FORMAT_DIFFSTAT:
1689                         diff_flush_stat(p, options, diffstat);
1690                         break;
1691                 case DIFF_FORMAT_PATCH:
1692                         diff_flush_patch(p, options);
1693                         break;
1694                 case DIFF_FORMAT_RAW:
1695                 case DIFF_FORMAT_NAME_STATUS:
1696                         diff_flush_raw(p, line_termination,
1697                                        inter_name_termination,
1698                                        options, diff_output_format);
1699                         break;
1700                 case DIFF_FORMAT_NAME:
1701                         diff_flush_name(p,
1702                                         inter_name_termination,
1703                                         line_termination);
1704                         break;
1705                 case DIFF_FORMAT_NO_OUTPUT:
1706                         break;
1707                 }
1708         }
1709 }
1710
1711 void diff_flush(struct diff_options *options)
1712 {
1713         struct diff_queue_struct *q = &diff_queued_diff;
1714         int i;
1715         int diff_output_format = options->output_format;
1716         struct diffstat_t *diffstat = NULL;
1717
1718         if (diff_output_format == DIFF_FORMAT_DIFFSTAT || options->with_stat) {
1719                 diffstat = xcalloc(sizeof (struct diffstat_t), 1);
1720                 diffstat->xm.consume = diffstat_consume;
1721         }
1722
1723         if (options->with_raw) {
1724                 for (i = 0; i < q->nr; i++) {
1725                         struct diff_filepair *p = q->queue[i];
1726                         flush_one_pair(p, DIFF_FORMAT_RAW, options, NULL);
1727                 }
1728                 putchar(options->line_termination);
1729         }
1730         if (options->with_stat) {
1731                 for (i = 0; i < q->nr; i++) {
1732                         struct diff_filepair *p = q->queue[i];
1733                         flush_one_pair(p, DIFF_FORMAT_DIFFSTAT, options,
1734                                        diffstat);
1735                 }
1736                 show_stats(diffstat);
1737                 free(diffstat);
1738                 diffstat = NULL;
1739                 putchar(options->line_termination);
1740         }
1741         for (i = 0; i < q->nr; i++) {
1742                 struct diff_filepair *p = q->queue[i];
1743                 flush_one_pair(p, diff_output_format, options, diffstat);
1744                 diff_free_filepair(p);
1745         }
1746
1747         if (diffstat) {
1748                 show_stats(diffstat);
1749                 free(diffstat);
1750         }
1751
1752         free(q->queue);
1753         q->queue = NULL;
1754         q->nr = q->alloc = 0;
1755 }
1756
1757 static void diffcore_apply_filter(const char *filter)
1758 {
1759         int i;
1760         struct diff_queue_struct *q = &diff_queued_diff;
1761         struct diff_queue_struct outq;
1762         outq.queue = NULL;
1763         outq.nr = outq.alloc = 0;
1764
1765         if (!filter)
1766                 return;
1767
1768         if (strchr(filter, DIFF_STATUS_FILTER_AON)) {
1769                 int found;
1770                 for (i = found = 0; !found && i < q->nr; i++) {
1771                         struct diff_filepair *p = q->queue[i];
1772                         if (((p->status == DIFF_STATUS_MODIFIED) &&
1773                              ((p->score &&
1774                                strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
1775                               (!p->score &&
1776                                strchr(filter, DIFF_STATUS_MODIFIED)))) ||
1777                             ((p->status != DIFF_STATUS_MODIFIED) &&
1778                              strchr(filter, p->status)))
1779                                 found++;
1780                 }
1781                 if (found)
1782                         return;
1783
1784                 /* otherwise we will clear the whole queue
1785                  * by copying the empty outq at the end of this
1786                  * function, but first clear the current entries
1787                  * in the queue.
1788                  */
1789                 for (i = 0; i < q->nr; i++)
1790                         diff_free_filepair(q->queue[i]);
1791         }
1792         else {
1793                 /* Only the matching ones */
1794                 for (i = 0; i < q->nr; i++) {
1795                         struct diff_filepair *p = q->queue[i];
1796
1797                         if (((p->status == DIFF_STATUS_MODIFIED) &&
1798                              ((p->score &&
1799                                strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
1800                               (!p->score &&
1801                                strchr(filter, DIFF_STATUS_MODIFIED)))) ||
1802                             ((p->status != DIFF_STATUS_MODIFIED) &&
1803                              strchr(filter, p->status)))
1804                                 diff_q(&outq, p);
1805                         else
1806                                 diff_free_filepair(p);
1807                 }
1808         }
1809         free(q->queue);
1810         *q = outq;
1811 }
1812
1813 void diffcore_std(struct diff_options *options)
1814 {
1815         if (options->break_opt != -1)
1816                 diffcore_break(options->break_opt);
1817         if (options->detect_rename)
1818                 diffcore_rename(options);
1819         if (options->break_opt != -1)
1820                 diffcore_merge_broken();
1821         if (options->pickaxe)
1822                 diffcore_pickaxe(options->pickaxe, options->pickaxe_opts);
1823         if (options->orderfile)
1824                 diffcore_order(options->orderfile);
1825         diff_resolve_rename_copy();
1826         diffcore_apply_filter(options->filter);
1827 }
1828
1829
1830 void diffcore_std_no_resolve(struct diff_options *options)
1831 {
1832         if (options->pickaxe)
1833                 diffcore_pickaxe(options->pickaxe, options->pickaxe_opts);
1834         if (options->orderfile)
1835                 diffcore_order(options->orderfile);
1836         diffcore_apply_filter(options->filter);
1837 }
1838
1839 void diff_addremove(struct diff_options *options,
1840                     int addremove, unsigned mode,
1841                     const unsigned char *sha1,
1842                     const char *base, const char *path)
1843 {
1844         char concatpath[PATH_MAX];
1845         struct diff_filespec *one, *two;
1846
1847         /* This may look odd, but it is a preparation for
1848          * feeding "there are unchanged files which should
1849          * not produce diffs, but when you are doing copy
1850          * detection you would need them, so here they are"
1851          * entries to the diff-core.  They will be prefixed
1852          * with something like '=' or '*' (I haven't decided
1853          * which but should not make any difference).
1854          * Feeding the same new and old to diff_change()
1855          * also has the same effect.
1856          * Before the final output happens, they are pruned after
1857          * merged into rename/copy pairs as appropriate.
1858          */
1859         if (options->reverse_diff)
1860                 addremove = (addremove == '+' ? '-' :
1861                              addremove == '-' ? '+' : addremove);
1862
1863         if (!path) path = "";
1864         sprintf(concatpath, "%s%s", base, path);
1865         one = alloc_filespec(concatpath);
1866         two = alloc_filespec(concatpath);
1867
1868         if (addremove != '+')
1869                 fill_filespec(one, sha1, mode);
1870         if (addremove != '-')
1871                 fill_filespec(two, sha1, mode);
1872
1873         diff_queue(&diff_queued_diff, one, two);
1874 }
1875
1876 void diff_change(struct diff_options *options,
1877                  unsigned old_mode, unsigned new_mode,
1878                  const unsigned char *old_sha1,
1879                  const unsigned char *new_sha1,
1880                  const char *base, const char *path)
1881 {
1882         char concatpath[PATH_MAX];
1883         struct diff_filespec *one, *two;
1884
1885         if (options->reverse_diff) {
1886                 unsigned tmp;
1887                 const unsigned char *tmp_c;
1888                 tmp = old_mode; old_mode = new_mode; new_mode = tmp;
1889                 tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
1890         }
1891         if (!path) path = "";
1892         sprintf(concatpath, "%s%s", base, path);
1893         one = alloc_filespec(concatpath);
1894         two = alloc_filespec(concatpath);
1895         fill_filespec(one, old_sha1, old_mode);
1896         fill_filespec(two, new_sha1, new_mode);
1897
1898         diff_queue(&diff_queued_diff, one, two);
1899 }
1900
1901 void diff_unmerge(struct diff_options *options,
1902                   const char *path)
1903 {
1904         struct diff_filespec *one, *two;
1905         one = alloc_filespec(path);
1906         two = alloc_filespec(path);
1907         diff_queue(&diff_queued_diff, one, two);
1908 }