read-cache.c

   1 /*
   2  * GIT - The information manager from hell
   3  *
   4  * Copyright (C) Linus Torvalds, 2005
   5  */
   6 #define NO_THE_INDEX_COMPATIBILITY_MACROS
   7 #include "cache.h"
   8 #include "cache-tree.h"
   9 #include "refs.h"
  10 #include "dir.h"
  11
  12 /* Index extensions.
  13  *
  14  * The first letter should be 'A'..'Z' for extensions that are not
  15  * necessary for a correct operation (i.e. optimization data).
  16  * When new extensions are added that _needs_ to be understood in
  17  * order to correctly interpret the index file, pick character that
  18  * is outside the range, to cause the reader to abort.
  19  */
  20
  21 #define CACHE_EXT(s) ( (s[0]<<24)|(s[1]<<16)|(s[2]<<8)|(s[3]) )
  22 #define CACHE_EXT_TREE 0x54524545       /* "TREE" */
  23
  24 struct index_state the_index;
  25
  26 static void set_index_entry(struct index_state *istate, int nr, struct cache_entry *ce)
  27 {
  28         istate->cache[nr] = ce;
  29         add_name_hash(istate, ce);
  30 }
  31
  32 static void replace_index_entry(struct index_state *istate, int nr, struct cache_entry *ce)
  33 {
  34         struct cache_entry *old = istate->cache[nr];
  35
  36         remove_name_hash(old);
  37         set_index_entry(istate, nr, ce);
  38         istate->cache_changed = 1;
  39 }
  40
  41 /*
  42  * This only updates the "non-critical" parts of the directory
  43  * cache, ie the parts that aren't tracked by GIT, and only used
  44  * to validate the cache.
  45  */
  46 void fill_stat_cache_info(struct cache_entry *ce, struct stat *st)
  47 {
  48         ce->ce_ctime = st->st_ctime;
  49         ce->ce_mtime = st->st_mtime;
  50         ce->ce_dev = st->st_dev;
  51         ce->ce_ino = st->st_ino;
  52         ce->ce_uid = st->st_uid;
  53         ce->ce_gid = st->st_gid;
  54         ce->ce_size = st->st_size;
  55
  56         if (assume_unchanged)
  57                 ce->ce_flags |= CE_VALID;
  58
  59         if (S_ISREG(st->st_mode))
  60                 ce_mark_uptodate(ce);
  61 }
  62
  63 static int ce_compare_data(struct cache_entry *ce, struct stat *st)
  64 {
  65         int match = -1;
  66         int fd = open(ce->name, O_RDONLY);
  67
  68         if (fd >= 0) {
  69                 unsigned char sha1[20];
  70                 if (!index_fd(sha1, fd, st, 0, OBJ_BLOB, ce->name))
  71                         match = hashcmp(sha1, ce->sha1);
  72                 /* index_fd() closed the file descriptor already */
  73         }
  74         return match;
  75 }
  76
  77 static int ce_compare_link(struct cache_entry *ce, size_t expected_size)
  78 {
  79         int match = -1;
  80         char *target;
  81         void *buffer;
  82         unsigned long size;
  83         enum object_type type;
  84         int len;
  85
  86         target = xmalloc(expected_size);
  87         len = readlink(ce->name, target, expected_size);
  88         if (len != expected_size) {
  89                 free(target);
  90                 return -1;
  91         }
  92         buffer = read_sha1_file(ce->sha1, &type, &size);
  93         if (!buffer) {
  94                 free(target);
  95                 return -1;
  96         }
  97         if (size == expected_size)
  98                 match = memcmp(buffer, target, size);
  99         free(buffer);
 100         free(target);
 101         return match;
 102 }
 103
 104 static int ce_compare_gitlink(struct cache_entry *ce)
 105 {
 106         unsigned char sha1[20];
 107
 108         /*
 109          * We don't actually require that the .git directory
 110          * under GITLINK directory be a valid git directory. It
 111          * might even be missing (in case nobody populated that
 112          * sub-project).
 113          *
 114          * If so, we consider it always to match.
 115          */
 116         if (resolve_gitlink_ref(ce->name, "HEAD", sha1) < 0)
 117                 return 0;
 118         return hashcmp(sha1, ce->sha1);
 119 }
 120
 121 static int ce_modified_check_fs(struct cache_entry *ce, struct stat *st)
 122 {
 123         switch (st->st_mode & S_IFMT) {
 124         case S_IFREG:
 125                 if (ce_compare_data(ce, st))
 126                         return DATA_CHANGED;
 127                 break;
 128         case S_IFLNK:
 129                 if (ce_compare_link(ce, xsize_t(st->st_size)))
 130                         return DATA_CHANGED;
 131                 break;
 132         case S_IFDIR:
 133                 if (S_ISGITLINK(ce->ce_mode))
 134                         return 0;
 135         default:
 136                 return TYPE_CHANGED;
 137         }
 138         return 0;
 139 }
 140
 141 static int is_empty_blob_sha1(const unsigned char *sha1)
 142 {
 143         static const unsigned char empty_blob_sha1[20] = {
 144                 0xe6,0x9d,0xe2,0x9b,0xb2,0xd1,0xd6,0x43,0x4b,0x8b,
 145                 0x29,0xae,0x77,0x5a,0xd8,0xc2,0xe4,0x8c,0x53,0x91
 146         };
 147
 148         return !hashcmp(sha1, empty_blob_sha1);
 149 }
 150
 151 static int ce_match_stat_basic(struct cache_entry *ce, struct stat *st)
 152 {
 153         unsigned int changed = 0;
 154
 155         if (ce->ce_flags & CE_REMOVE)
 156                 return MODE_CHANGED | DATA_CHANGED | TYPE_CHANGED;
 157
 158         switch (ce->ce_mode & S_IFMT) {
 159         case S_IFREG:
 160                 changed |= !S_ISREG(st->st_mode) ? TYPE_CHANGED : 0;
 161                 /* We consider only the owner x bit to be relevant for
 162                  * "mode changes"
 163                  */
 164                 if (trust_executable_bit &&
 165                     (0100 & (ce->ce_mode ^ st->st_mode)))
 166                         changed |= MODE_CHANGED;
 167                 break;
 168         case S_IFLNK:
 169                 if (!S_ISLNK(st->st_mode) &&
 170                     (has_symlinks || !S_ISREG(st->st_mode)))
 171                         changed |= TYPE_CHANGED;
 172                 break;
 173         case S_IFGITLINK:
 174                 if (!S_ISDIR(st->st_mode))
 175                         changed |= TYPE_CHANGED;
 176                 else if (ce_compare_gitlink(ce))
 177                         changed |= DATA_CHANGED;
 178                 return changed;
 179         default:
 180                 die("internal error: ce_mode is %o", ce->ce_mode);
 181         }
 182         if (ce->ce_mtime != (unsigned int) st->st_mtime)
 183                 changed |= MTIME_CHANGED;
 184         if (ce->ce_ctime != (unsigned int) st->st_ctime)
 185                 changed |= CTIME_CHANGED;
 186
 187         if (ce->ce_uid != (unsigned int) st->st_uid ||
 188             ce->ce_gid != (unsigned int) st->st_gid)
 189                 changed |= OWNER_CHANGED;
 190         if (ce->ce_ino != (unsigned int) st->st_ino)
 191                 changed |= INODE_CHANGED;
 192
 193 #ifdef USE_STDEV
 194         /*
 195          * st_dev breaks on network filesystems where different
 196          * clients will have different views of what "device"
 197          * the filesystem is on
 198          */
 199         if (ce->ce_dev != (unsigned int) st->st_dev)
 200                 changed |= INODE_CHANGED;
 201 #endif
 202
 203         if (ce->ce_size != (unsigned int) st->st_size)
 204                 changed |= DATA_CHANGED;
 205
 206         /* Racily smudged entry? */
 207         if (!ce->ce_size) {
 208                 if (!is_empty_blob_sha1(ce->sha1))
 209                         changed |= DATA_CHANGED;
 210         }
 211
 212         return changed;
 213 }
 214
 215 static int is_racy_timestamp(const struct index_state *istate, struct cache_entry *ce)
 216 {
 217         return (!S_ISGITLINK(ce->ce_mode) &&
 218                 istate->timestamp &&
 219                 ((unsigned int)istate->timestamp) <= ce->ce_mtime);
 220 }
 221
 222 int ie_match_stat(const struct index_state *istate,
 223                   struct cache_entry *ce, struct stat *st,
 224                   unsigned int options)
 225 {
 226         unsigned int changed;
 227         int ignore_valid = options & CE_MATCH_IGNORE_VALID;
 228         int assume_racy_is_modified = options & CE_MATCH_RACY_IS_DIRTY;
 229
 230         /*
 231          * If it's marked as always valid in the index, it's
 232          * valid whatever the checked-out copy says.
 233          */
 234         if (!ignore_valid && (ce->ce_flags & CE_VALID))
 235                 return 0;
 236
 237         changed = ce_match_stat_basic(ce, st);
 238
 239         /*
 240          * Within 1 second of this sequence:
 241          *      echo xyzzy >file && git-update-index --add file
 242          * running this command:
 243          *      echo frotz >file
 244          * would give a falsely clean cache entry.  The mtime and
 245          * length match the cache, and other stat fields do not change.
 246          *
 247          * We could detect this at update-index time (the cache entry
 248          * being registered/updated records the same time as "now")
 249          * and delay the return from git-update-index, but that would
 250          * effectively mean we can make at most one commit per second,
 251          * which is not acceptable.  Instead, we check cache entries
 252          * whose mtime are the same as the index file timestamp more
 253          * carefully than others.
 254          */
 255         if (!changed && is_racy_timestamp(istate, ce)) {
 256                 if (assume_racy_is_modified)
 257                         changed |= DATA_CHANGED;
 258                 else
 259                         changed |= ce_modified_check_fs(ce, st);
 260         }
 261
 262         return changed;
 263 }
 264
 265 int ie_modified(const struct index_state *istate,
 266                 struct cache_entry *ce, struct stat *st, unsigned int options)
 267 {
 268         int changed, changed_fs;
 269
 270         changed = ie_match_stat(istate, ce, st, options);
 271         if (!changed)
 272                 return 0;
 273         /*
 274          * If the mode or type has changed, there's no point in trying
 275          * to refresh the entry - it's not going to match
 276          */
 277         if (changed & (MODE_CHANGED | TYPE_CHANGED))
 278                 return changed;
 279
 280         /* Immediately after read-tree or update-index --cacheinfo,
 281          * the length field is zero.  For other cases the ce_size
 282          * should match the SHA1 recorded in the index entry.
 283          */
 284         if ((changed & DATA_CHANGED) && ce->ce_size != 0)
 285                 return changed;
 286
 287         changed_fs = ce_modified_check_fs(ce, st);
 288         if (changed_fs)
 289                 return changed | changed_fs;
 290         return 0;
 291 }
 292
 293 int base_name_compare(const char *name1, int len1, int mode1,
 294                       const char *name2, int len2, int mode2)
 295 {
 296         unsigned char c1, c2;
 297         int len = len1 < len2 ? len1 : len2;
 298         int cmp;
 299
 300         cmp = memcmp(name1, name2, len);
 301         if (cmp)
 302                 return cmp;
 303         c1 = name1[len];
 304         c2 = name2[len];
 305         if (!c1 && S_ISDIR(mode1))
 306                 c1 = '/';
 307         if (!c2 && S_ISDIR(mode2))
 308                 c2 = '/';
 309         return (c1 < c2) ? -1 : (c1 > c2) ? 1 : 0;
 310 }
 311
 312 /*
 313  * df_name_compare() is identical to base_name_compare(), except it
 314  * compares conflicting directory/file entries as equal. Note that
 315  * while a directory name compares as equal to a regular file, they
 316  * then individually compare _differently_ to a filename that has
 317  * a dot after the basename (because '\0' < '.' < '/').
 318  *
 319  * This is used by routines that want to traverse the git namespace
 320  * but then handle conflicting entries together when possible.
 321  */
 322 int df_name_compare(const char *name1, int len1, int mode1,
 323                     const char *name2, int len2, int mode2)
 324 {
 325         int len = len1 < len2 ? len1 : len2, cmp;
 326         unsigned char c1, c2;
 327
 328         cmp = memcmp(name1, name2, len);
 329         if (cmp)
 330                 return cmp;
 331         /* Directories and files compare equal (same length, same name) */
 332         if (len1 == len2)
 333                 return 0;
 334         c1 = name1[len];
 335         if (!c1 && S_ISDIR(mode1))
 336                 c1 = '/';
 337         c2 = name2[len];
 338         if (!c2 && S_ISDIR(mode2))
 339                 c2 = '/';
 340         if (c1 == '/' && !c2)
 341                 return 0;
 342         if (c2 == '/' && !c1)
 343                 return 0;
 344         return c1 - c2;
 345 }
 346
 347 int cache_name_compare(const char *name1, int flags1, const char *name2, int flags2)
 348 {
 349         int len1 = flags1 & CE_NAMEMASK;
 350         int len2 = flags2 & CE_NAMEMASK;
 351         int len = len1 < len2 ? len1 : len2;
 352         int cmp;
 353
 354         cmp = memcmp(name1, name2, len);
 355         if (cmp)
 356                 return cmp;
 357         if (len1 < len2)
 358                 return -1;
 359         if (len1 > len2)
 360                 return 1;
 361
 362         /* Compare stages  */
 363         flags1 &= CE_STAGEMASK;
 364         flags2 &= CE_STAGEMASK;
 365
 366         if (flags1 < flags2)
 367                 return -1;
 368         if (flags1 > flags2)
 369                 return 1;
 370         return 0;
 371 }
 372
 373 int index_name_pos(const struct index_state *istate, const char *name, int namelen)
 374 {
 375         int first, last;
 376
 377         first = 0;
 378         last = istate->cache_nr;
 379         while (last > first) {
 380                 int next = (last + first) >> 1;
 381                 struct cache_entry *ce = istate->cache[next];
 382                 int cmp = cache_name_compare(name, namelen, ce->name, ce->ce_flags);
 383                 if (!cmp)
 384                         return next;
 385                 if (cmp < 0) {
 386                         last = next;
 387                         continue;
 388                 }
 389                 first = next+1;
 390         }
 391         return -first-1;
 392 }
 393
 394 /* Remove entry, return true if there are more entries to go.. */
 395 int remove_index_entry_at(struct index_state *istate, int pos)
 396 {
 397         struct cache_entry *ce = istate->cache[pos];
 398
 399         remove_name_hash(ce);
 400         istate->cache_changed = 1;
 401         istate->cache_nr--;
 402         if (pos >= istate->cache_nr)
 403                 return 0;
 404         memmove(istate->cache + pos,
 405                 istate->cache + pos + 1,
 406                 (istate->cache_nr - pos) * sizeof(struct cache_entry *));
 407         return 1;
 408 }
 409
 410 int remove_file_from_index(struct index_state *istate, const char *path)
 411 {
 412         int pos = index_name_pos(istate, path, strlen(path));
 413         if (pos < 0)
 414                 pos = -pos-1;
 415         cache_tree_invalidate_path(istate->cache_tree, path);
 416         while (pos < istate->cache_nr && !strcmp(istate->cache[pos]->name, path))
 417                 remove_index_entry_at(istate, pos);
 418         return 0;
 419 }
 420
 421 static int compare_name(struct cache_entry *ce, const char *path, int namelen)
 422 {
 423         return namelen != ce_namelen(ce) || memcmp(path, ce->name, namelen);
 424 }
 425
 426 static int index_name_pos_also_unmerged(struct index_state *istate,
 427         const char *path, int namelen)
 428 {
 429         int pos = index_name_pos(istate, path, namelen);
 430         struct cache_entry *ce;
 431
 432         if (pos >= 0)
 433                 return pos;
 434
 435         /* maybe unmerged? */
 436         pos = -1 - pos;
 437         if (pos >= istate->cache_nr ||
 438                         compare_name((ce = istate->cache[pos]), path, namelen))
 439                 return -1;
 440
 441         /* order of preference: stage 2, 1, 3 */
 442         if (ce_stage(ce) == 1 && pos + 1 < istate->cache_nr &&
 443                         ce_stage((ce = istate->cache[pos + 1])) == 2 &&
 444                         !compare_name(ce, path, namelen))
 445                 pos++;
 446         return pos;
 447 }
 448
 449 static int different_name(struct cache_entry *ce, struct cache_entry *alias)
 450 {
 451         int len = ce_namelen(ce);
 452         return ce_namelen(alias) != len || memcmp(ce->name, alias->name, len);
 453 }
 454
 455 /*
 456  * If we add a filename that aliases in the cache, we will use the
 457  * name that we already have - but we don't want to update the same
 458  * alias twice, because that implies that there were actually two
 459  * different files with aliasing names!
 460  *
 461  * So we use the CE_ADDED flag to verify that the alias was an old
 462  * one before we accept it as
 463  */
 464 static struct cache_entry *create_alias_ce(struct cache_entry *ce, struct cache_entry *alias)
 465 {
 466         int len;
 467         struct cache_entry *new;
 468
 469         if (alias->ce_flags & CE_ADDED)
 470                 die("Will not add file alias '%s' ('%s' already exists in index)", ce->name, alias->name);
 471
 472         /* Ok, create the new entry using the name of the existing alias */
 473         len = ce_namelen(alias);
 474         new = xcalloc(1, cache_entry_size(len));
 475         memcpy(new->name, alias->name, len);
 476         copy_cache_entry(new, ce);
 477         free(ce);
 478         return new;
 479 }
 480
 481 int add_to_index(struct index_state *istate, const char *path, struct stat *st, int flags)
 482 {
 483         int size, namelen, was_same;
 484         mode_t st_mode = st->st_mode;
 485         struct cache_entry *ce, *alias;
 486         unsigned ce_option = CE_MATCH_IGNORE_VALID|CE_MATCH_RACY_IS_DIRTY;
 487         int verbose = flags & (ADD_CACHE_VERBOSE | ADD_CACHE_PRETEND);
 488         int pretend = flags & ADD_CACHE_PRETEND;
 489
 490         if (!S_ISREG(st_mode) && !S_ISLNK(st_mode) && !S_ISDIR(st_mode))
 491                 return error("%s: can only add regular files, symbolic links or git-directories", path);
 492
 493         namelen = strlen(path);
 494         if (S_ISDIR(st_mode)) {
 495                 while (namelen && path[namelen-1] == '/')
 496                         namelen--;
 497         }
 498         size = cache_entry_size(namelen);
 499         ce = xcalloc(1, size);
 500         memcpy(ce->name, path, namelen);
 501         ce->ce_flags = namelen;
 502         fill_stat_cache_info(ce, st);
 503
 504         if (trust_executable_bit && has_symlinks)
 505                 ce->ce_mode = create_ce_mode(st_mode);
 506         else {
 507                 /* If there is an existing entry, pick the mode bits and type
 508                  * from it, otherwise assume unexecutable regular file.
 509                  */
 510                 struct cache_entry *ent;
 511                 int pos = index_name_pos_also_unmerged(istate, path, namelen);
 512
 513                 ent = (0 <= pos) ? istate->cache[pos] : NULL;
 514                 ce->ce_mode = ce_mode_from_stat(ent, st_mode);
 515         }
 516
 517         alias = index_name_exists(istate, ce->name, ce_namelen(ce), ignore_case);
 518         if (alias && !ce_stage(alias) && !ie_match_stat(istate, alias, st, ce_option)) {
 519                 /* Nothing changed, really */
 520                 free(ce);
 521                 ce_mark_uptodate(alias);
 522                 alias->ce_flags |= CE_ADDED;
 523                 return 0;
 524         }
 525         if (index_path(ce->sha1, path, st, 1))
 526                 return error("unable to index file %s", path);
 527         if (ignore_case && alias && different_name(ce, alias))
 528                 ce = create_alias_ce(ce, alias);
 529         ce->ce_flags |= CE_ADDED;
 530
 531         /* It was suspected to be racily clean, but it turns out to be Ok */
 532         was_same = (alias &&
 533                     !ce_stage(alias) &&
 534                     !hashcmp(alias->sha1, ce->sha1) &&
 535                     ce->ce_mode == alias->ce_mode);
 536
 537         if (pretend)
 538                 ;
 539         else if (add_index_entry(istate, ce, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE))
 540                 return error("unable to add %s to index",path);
 541         if (verbose && !was_same)
 542                 printf("add '%s'\n", path);
 543         return 0;
 544 }
 545
 546 int add_file_to_index(struct index_state *istate, const char *path, int flags)
 547 {
 548         struct stat st;
 549         if (lstat(path, &st))
 550                 die("%s: unable to stat (%s)", path, strerror(errno));
 551         return add_to_index(istate, path, &st, flags);
 552 }
 553
 554 struct cache_entry *make_cache_entry(unsigned int mode,
 555                 const unsigned char *sha1, const char *path, int stage,
 556                 int refresh)
 557 {
 558         int size, len;
 559         struct cache_entry *ce;
 560
 561         if (!verify_path(path))
 562                 return NULL;
 563
 564         len = strlen(path);
 565         size = cache_entry_size(len);
 566         ce = xcalloc(1, size);
 567
 568         hashcpy(ce->sha1, sha1);
 569         memcpy(ce->name, path, len);
 570         ce->ce_flags = create_ce_flags(len, stage);
 571         ce->ce_mode = create_ce_mode(mode);
 572
 573         if (refresh)
 574                 return refresh_cache_entry(ce, 0);
 575
 576         return ce;
 577 }
 578
 579 int ce_same_name(struct cache_entry *a, struct cache_entry *b)
 580 {
 581         int len = ce_namelen(a);
 582         return ce_namelen(b) == len && !memcmp(a->name, b->name, len);
 583 }
 584
 585 int ce_path_match(const struct cache_entry *ce, const char **pathspec)
 586 {
 587         const char *match, *name;
 588         int len;
 589
 590         if (!pathspec)
 591                 return 1;
 592
 593         len = ce_namelen(ce);
 594         name = ce->name;
 595         while ((match = *pathspec++) != NULL) {
 596                 int matchlen = strlen(match);
 597                 if (matchlen > len)
 598                         continue;
 599                 if (memcmp(name, match, matchlen))
 600                         continue;
 601                 if (matchlen && name[matchlen-1] == '/')
 602                         return 1;
 603                 if (name[matchlen] == '/' || !name[matchlen])
 604                         return 1;
 605                 if (!matchlen)
 606                         return 1;
 607         }
 608         return 0;
 609 }
 610
 611 /*
 612  * We fundamentally don't like some paths: we don't want
 613  * dot or dot-dot anywhere, and for obvious reasons don't
 614  * want to recurse into ".git" either.
 615  *
 616  * Also, we don't want double slashes or slashes at the
 617  * end that can make pathnames ambiguous.
 618  */
 619 static int verify_dotfile(const char *rest)
 620 {
 621         /*
 622          * The first character was '.', but that
 623          * has already been discarded, we now test
 624          * the rest.
 625          */
 626         switch (*rest) {
 627         /* "." is not allowed */
 628         case '\0': case '/':
 629                 return 0;
 630
 631         /*
 632          * ".git" followed by  NUL or slash is bad. This
 633          * shares the path end test with the ".." case.
 634          */
 635         case 'g':
 636                 if (rest[1] != 'i')
 637                         break;
 638                 if (rest[2] != 't')
 639                         break;
 640                 rest += 2;
 641         /* fallthrough */
 642         case '.':
 643                 if (rest[1] == '\0' || rest[1] == '/')
 644                         return 0;
 645         }
 646         return 1;
 647 }
 648
 649 int verify_path(const char *path)
 650 {
 651         char c;
 652
 653         goto inside;
 654         for (;;) {
 655                 if (!c)
 656                         return 1;
 657                 if (c == '/') {
 658 inside:
 659                         c = *path++;
 660                         switch (c) {
 661                         default:
 662                                 continue;
 663                         case '/': case '\0':
 664                                 break;
 665                         case '.':
 666                                 if (verify_dotfile(path))
 667                                         continue;
 668                         }
 669                         return 0;
 670                 }
 671                 c = *path++;
 672         }
 673 }
 674
 675 /*
 676  * Do we have another file that has the beginning components being a
 677  * proper superset of the name we're trying to add?
 678  */
 679 static int has_file_name(struct index_state *istate,
 680                          const struct cache_entry *ce, int pos, int ok_to_replace)
 681 {
 682         int retval = 0;
 683         int len = ce_namelen(ce);
 684         int stage = ce_stage(ce);
 685         const char *name = ce->name;
 686
 687         while (pos < istate->cache_nr) {
 688                 struct cache_entry *p = istate->cache[pos++];
 689
 690                 if (len >= ce_namelen(p))
 691                         break;
 692                 if (memcmp(name, p->name, len))
 693                         break;
 694                 if (ce_stage(p) != stage)
 695                         continue;
 696                 if (p->name[len] != '/')
 697                         continue;
 698                 if (p->ce_flags & CE_REMOVE)
 699                         continue;
 700                 retval = -1;
 701                 if (!ok_to_replace)
 702                         break;
 703                 remove_index_entry_at(istate, --pos);
 704         }
 705         return retval;
 706 }
 707
 708 /*
 709  * Do we have another file with a pathname that is a proper
 710  * subset of the name we're trying to add?
 711  */
 712 static int has_dir_name(struct index_state *istate,
 713                         const struct cache_entry *ce, int pos, int ok_to_replace)
 714 {
 715         int retval = 0;
 716         int stage = ce_stage(ce);
 717         const char *name = ce->name;
 718         const char *slash = name + ce_namelen(ce);
 719
 720         for (;;) {
 721                 int len;
 722
 723                 for (;;) {
 724                         if (*--slash == '/')
 725                                 break;
 726                         if (slash <= ce->name)
 727                                 return retval;
 728                 }
 729                 len = slash - name;
 730
 731                 pos = index_name_pos(istate, name, create_ce_flags(len, stage));
 732                 if (pos >= 0) {
 733                         /*
 734                          * Found one, but not so fast.  This could
 735                          * be a marker that says "I was here, but
 736                          * I am being removed".  Such an entry is
 737                          * not a part of the resulting tree, and
 738                          * it is Ok to have a directory at the same
 739                          * path.
 740                          */
 741                         if (!(istate->cache[pos]->ce_flags & CE_REMOVE)) {
 742                                 retval = -1;
 743                                 if (!ok_to_replace)
 744                                         break;
 745                                 remove_index_entry_at(istate, pos);
 746                                 continue;
 747                         }
 748                 }
 749                 else
 750                         pos = -pos-1;
 751
 752                 /*
 753                  * Trivial optimization: if we find an entry that
 754                  * already matches the sub-directory, then we know
 755                  * we're ok, and we can exit.
 756                  */
 757                 while (pos < istate->cache_nr) {
 758                         struct cache_entry *p = istate->cache[pos];
 759                         if ((ce_namelen(p) <= len) ||
 760                             (p->name[len] != '/') ||
 761                             memcmp(p->name, name, len))
 762                                 break; /* not our subdirectory */
 763                         if (ce_stage(p) == stage && !(p->ce_flags & CE_REMOVE))
 764                                 /*
 765                                  * p is at the same stage as our entry, and
 766                                  * is a subdirectory of what we are looking
 767                                  * at, so we cannot have conflicts at our
 768                                  * level or anything shorter.
 769                                  */
 770                                 return retval;
 771                         pos++;
 772                 }
 773         }
 774         return retval;
 775 }
 776
 777 /* We may be in a situation where we already have path/file and path
 778  * is being added, or we already have path and path/file is being
 779  * added.  Either one would result in a nonsense tree that has path
 780  * twice when git-write-tree tries to write it out.  Prevent it.
 781  *
 782  * If ok-to-replace is specified, we remove the conflicting entries
 783  * from the cache so the caller should recompute the insert position.
 784  * When this happens, we return non-zero.
 785  */
 786 static int check_file_directory_conflict(struct index_state *istate,
 787                                          const struct cache_entry *ce,
 788                                          int pos, int ok_to_replace)
 789 {
 790         int retval;
 791
 792         /*
 793          * When ce is an "I am going away" entry, we allow it to be added
 794          */
 795         if (ce->ce_flags & CE_REMOVE)
 796                 return 0;
 797
 798         /*
 799          * We check if the path is a sub-path of a subsequent pathname
 800          * first, since removing those will not change the position
 801          * in the array.
 802          */
 803         retval = has_file_name(istate, ce, pos, ok_to_replace);
 804
 805         /*
 806          * Then check if the path might have a clashing sub-directory
 807          * before it.
 808          */
 809         return retval + has_dir_name(istate, ce, pos, ok_to_replace);
 810 }
 811
 812 static int add_index_entry_with_check(struct index_state *istate, struct cache_entry *ce, int option)
 813 {
 814         int pos;
 815         int ok_to_add = option & ADD_CACHE_OK_TO_ADD;
 816         int ok_to_replace = option & ADD_CACHE_OK_TO_REPLACE;
 817         int skip_df_check = option & ADD_CACHE_SKIP_DFCHECK;
 818
 819         cache_tree_invalidate_path(istate->cache_tree, ce->name);
 820         pos = index_name_pos(istate, ce->name, ce->ce_flags);
 821
 822         /* existing match? Just replace it. */
 823         if (pos >= 0) {
 824                 replace_index_entry(istate, pos, ce);
 825                 return 0;
 826         }
 827         pos = -pos-1;
 828
 829         /*
 830          * Inserting a merged entry ("stage 0") into the index
 831          * will always replace all non-merged entries..
 832          */
 833         if (pos < istate->cache_nr && ce_stage(ce) == 0) {
 834                 while (ce_same_name(istate->cache[pos], ce)) {
 835                         ok_to_add = 1;
 836                         if (!remove_index_entry_at(istate, pos))
 837                                 break;
 838                 }
 839         }
 840
 841         if (!ok_to_add)
 842                 return -1;
 843         if (!verify_path(ce->name))
 844                 return -1;
 845
 846         if (!skip_df_check &&
 847             check_file_directory_conflict(istate, ce, pos, ok_to_replace)) {
 848                 if (!ok_to_replace)
 849                         return error("'%s' appears as both a file and as a directory",
 850                                      ce->name);
 851                 pos = index_name_pos(istate, ce->name, ce->ce_flags);
 852                 pos = -pos-1;
 853         }
 854         return pos + 1;
 855 }
 856
 857 int add_index_entry(struct index_state *istate, struct cache_entry *ce, int option)
 858 {
 859         int pos;
 860
 861         if (option & ADD_CACHE_JUST_APPEND)
 862                 pos = istate->cache_nr;
 863         else {
 864                 int ret;
 865                 ret = add_index_entry_with_check(istate, ce, option);
 866                 if (ret <= 0)
 867                         return ret;
 868                 pos = ret - 1;
 869         }
 870
 871         /* Make sure the array is big enough .. */
 872         if (istate->cache_nr == istate->cache_alloc) {
 873                 istate->cache_alloc = alloc_nr(istate->cache_alloc);
 874                 istate->cache = xrealloc(istate->cache,
 875                                         istate->cache_alloc * sizeof(struct cache_entry *));
 876         }
 877
 878         /* Add it in.. */
 879         istate->cache_nr++;
 880         if (istate->cache_nr > pos + 1)
 881                 memmove(istate->cache + pos + 1,
 882                         istate->cache + pos,
 883                         (istate->cache_nr - pos - 1) * sizeof(ce));
 884         set_index_entry(istate, pos, ce);
 885         istate->cache_changed = 1;
 886         return 0;
 887 }
 888
 889 /*
 890  * "refresh" does not calculate a new sha1 file or bring the
 891  * cache up-to-date for mode/content changes. But what it
 892  * _does_ do is to "re-match" the stat information of a file
 893  * with the cache, so that you can refresh the cache for a
 894  * file that hasn't been changed but where the stat entry is
 895  * out of date.
 896  *
 897  * For example, you'd want to do this after doing a "git-read-tree",
 898  * to link up the stat cache details with the proper files.
 899  */
 900 static struct cache_entry *refresh_cache_ent(struct index_state *istate,
 901                                              struct cache_entry *ce,
 902                                              unsigned int options, int *err)
 903 {
 904         struct stat st;
 905         struct cache_entry *updated;
 906         int changed, size;
 907         int ignore_valid = options & CE_MATCH_IGNORE_VALID;
 908
 909         if (ce_uptodate(ce))
 910                 return ce;
 911
 912         /*
 913          * CE_VALID means the user promised us that the change to
 914          * the work tree does not matter and told us not to worry.
 915          */
 916         if (!ignore_valid && (ce->ce_flags & CE_VALID)) {
 917                 ce_mark_uptodate(ce);
 918                 return ce;
 919         }
 920
 921         if (lstat(ce->name, &st) < 0) {
 922                 if (err)
 923                         *err = errno;
 924                 return NULL;
 925         }
 926
 927         changed = ie_match_stat(istate, ce, &st, options);
 928         if (!changed) {
 929                 /*
 930                  * The path is unchanged.  If we were told to ignore
 931                  * valid bit, then we did the actual stat check and
 932                  * found that the entry is unmodified.  If the entry
 933                  * is not marked VALID, this is the place to mark it
 934                  * valid again, under "assume unchanged" mode.
 935                  */
 936                 if (ignore_valid && assume_unchanged &&
 937                     !(ce->ce_flags & CE_VALID))
 938                         ; /* mark this one VALID again */
 939                 else {
 940                         /*
 941                          * We do not mark the index itself "modified"
 942                          * because CE_UPTODATE flag is in-core only;
 943                          * we are not going to write this change out.
 944                          */
 945                         ce_mark_uptodate(ce);
 946                         return ce;
 947                 }
 948         }
 949
 950         if (ie_modified(istate, ce, &st, options)) {
 951                 if (err)
 952                         *err = EINVAL;
 953                 return NULL;
 954         }
 955
 956         size = ce_size(ce);
 957         updated = xmalloc(size);
 958         memcpy(updated, ce, size);
 959         fill_stat_cache_info(updated, &st);
 960         /*
 961          * If ignore_valid is not set, we should leave CE_VALID bit
 962          * alone.  Otherwise, paths marked with --no-assume-unchanged
 963          * (i.e. things to be edited) will reacquire CE_VALID bit
 964          * automatically, which is not really what we want.
 965          */
 966         if (!ignore_valid && assume_unchanged &&
 967             !(ce->ce_flags & CE_VALID))
 968                 updated->ce_flags &= ~CE_VALID;
 969
 970         return updated;
 971 }
 972
 973 int refresh_index(struct index_state *istate, unsigned int flags, const char **pathspec, char *seen)
 974 {
 975         int i;
 976         int has_errors = 0;
 977         int really = (flags & REFRESH_REALLY) != 0;
 978         int allow_unmerged = (flags & REFRESH_UNMERGED) != 0;
 979         int quiet = (flags & REFRESH_QUIET) != 0;
 980         int not_new = (flags & REFRESH_IGNORE_MISSING) != 0;
 981         int ignore_submodules = (flags & REFRESH_IGNORE_SUBMODULES) != 0;
 982         unsigned int options = really ? CE_MATCH_IGNORE_VALID : 0;
 983         const char *needs_update_message;
 984
 985         needs_update_message = ((flags & REFRESH_SAY_CHANGED)
 986                                 ? "locally modified" : "needs update");
 987         for (i = 0; i < istate->cache_nr; i++) {
 988                 struct cache_entry *ce, *new;
 989                 int cache_errno = 0;
 990
 991                 ce = istate->cache[i];
 992                 if (ignore_submodules && S_ISGITLINK(ce->ce_mode))
 993                         continue;
 994
 995                 if (ce_stage(ce)) {
 996                         while ((i < istate->cache_nr) &&
 997                                ! strcmp(istate->cache[i]->name, ce->name))
 998                                 i++;
 999                         i--;
1000                         if (allow_unmerged)
1001                                 continue;
1002                         printf("%s: needs merge\n", ce->name);
1003                         has_errors = 1;
1004                         continue;
1005                 }
1006
1007                 if (pathspec && !match_pathspec(pathspec, ce->name, strlen(ce->name), 0, seen))
1008                         continue;
1009
1010                 new = refresh_cache_ent(istate, ce, options, &cache_errno);
1011                 if (new == ce)
1012                         continue;
1013                 if (!new) {
1014                         if (not_new && cache_errno == ENOENT)
1015                                 continue;
1016                         if (really && cache_errno == EINVAL) {
1017                                 /* If we are doing --really-refresh that
1018                                  * means the index is not valid anymore.
1019                                  */
1020                                 ce->ce_flags &= ~CE_VALID;
1021                                 istate->cache_changed = 1;
1022                         }
1023                         if (quiet)
1024                                 continue;
1025                         printf("%s: %s\n", ce->name, needs_update_message);
1026                         has_errors = 1;
1027                         continue;
1028                 }
1029
1030                 replace_index_entry(istate, i, new);
1031         }
1032         return has_errors;
1033 }
1034
1035 struct cache_entry *refresh_cache_entry(struct cache_entry *ce, int really)
1036 {
1037         return refresh_cache_ent(&the_index, ce, really, NULL);
1038 }
1039
1040 static int verify_hdr(struct cache_header *hdr, unsigned long size)
1041 {
1042         SHA_CTX c;
1043         unsigned char sha1[20];
1044
1045         if (hdr->hdr_signature != htonl(CACHE_SIGNATURE))
1046                 return error("bad signature");
1047         if (hdr->hdr_version != htonl(2))
1048                 return error("bad index version");
1049         SHA1_Init(&c);
1050         SHA1_Update(&c, hdr, size - 20);
1051         SHA1_Final(sha1, &c);
1052         if (hashcmp(sha1, (unsigned char *)hdr + size - 20))
1053                 return error("bad index file sha1 signature");
1054         return 0;
1055 }
1056
1057 static int read_index_extension(struct index_state *istate,
1058                                 const char *ext, void *data, unsigned long sz)
1059 {
1060         switch (CACHE_EXT(ext)) {
1061         case CACHE_EXT_TREE:
1062                 istate->cache_tree = cache_tree_read(data, sz);
1063                 break;
1064         default:
1065                 if (*ext < 'A' || 'Z' < *ext)
1066                         return error("index uses %.4s extension, which we do not understand",
1067                                      ext);
1068                 fprintf(stderr, "ignoring %.4s extension\n", ext);
1069                 break;
1070         }
1071         return 0;
1072 }
1073
1074 int read_index(struct index_state *istate)
1075 {
1076         return read_index_from(istate, get_index_file());
1077 }
1078
1079 static void convert_from_disk(struct ondisk_cache_entry *ondisk, struct cache_entry *ce)
1080 {
1081         size_t len;
1082
1083         ce->ce_ctime = ntohl(ondisk->ctime.sec);
1084         ce->ce_mtime = ntohl(ondisk->mtime.sec);
1085         ce->ce_dev   = ntohl(ondisk->dev);
1086         ce->ce_ino   = ntohl(ondisk->ino);
1087         ce->ce_mode  = ntohl(ondisk->mode);
1088         ce->ce_uid   = ntohl(ondisk->uid);
1089         ce->ce_gid   = ntohl(ondisk->gid);
1090         ce->ce_size  = ntohl(ondisk->size);
1091         /* On-disk flags are just 16 bits */
1092         ce->ce_flags = ntohs(ondisk->flags);
1093         hashcpy(ce->sha1, ondisk->sha1);
1094
1095         len = ce->ce_flags & CE_NAMEMASK;
1096         if (len == CE_NAMEMASK)
1097                 len = strlen(ondisk->name);
1098         /*
1099          * NEEDSWORK: If the original index is crafted, this copy could
1100          * go unchecked.
1101          */
1102         memcpy(ce->name, ondisk->name, len + 1);
1103 }
1104
1105 static inline size_t estimate_cache_size(size_t ondisk_size, unsigned int entries)
1106 {
1107         long per_entry;
1108
1109         per_entry = sizeof(struct cache_entry) - sizeof(struct ondisk_cache_entry);
1110
1111         /*
1112          * Alignment can cause differences. This should be "alignof", but
1113          * since that's a gcc'ism, just use the size of a pointer.
1114          */
1115         per_entry += sizeof(void *);
1116         return ondisk_size + entries*per_entry;
1117 }
1118
1119 /* remember to discard_cache() before reading a different cache! */
1120 int read_index_from(struct index_state *istate, const char *path)
1121 {
1122         int fd, i;
1123         struct stat st;
1124         unsigned long src_offset, dst_offset;
1125         struct cache_header *hdr;
1126         void *mmap;
1127         size_t mmap_size;
1128
1129         errno = EBUSY;
1130         if (istate->alloc)
1131                 return istate->cache_nr;
1132
1133         errno = ENOENT;
1134         istate->timestamp = 0;
1135         fd = open(path, O_RDONLY);
1136         if (fd < 0) {
1137                 if (errno == ENOENT)
1138                         return 0;
1139                 die("index file open failed (%s)", strerror(errno));
1140         }
1141
1142         if (fstat(fd, &st))
1143                 die("cannot stat the open index (%s)", strerror(errno));
1144
1145         errno = EINVAL;
1146         mmap_size = xsize_t(st.st_size);
1147         if (mmap_size < sizeof(struct cache_header) + 20)
1148                 die("index file smaller than expected");
1149
1150         mmap = xmmap(NULL, mmap_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
1151         close(fd);
1152         if (mmap == MAP_FAILED)
1153                 die("unable to map index file");
1154
1155         hdr = mmap;
1156         if (verify_hdr(hdr, mmap_size) < 0)
1157                 goto unmap;
1158
1159         istate->cache_nr = ntohl(hdr->hdr_entries);
1160         istate->cache_alloc = alloc_nr(istate->cache_nr);
1161         istate->cache = xcalloc(istate->cache_alloc, sizeof(struct cache_entry *));
1162
1163         /*
1164          * The disk format is actually larger than the in-memory format,
1165          * due to space for nsec etc, so even though the in-memory one
1166          * has room for a few  more flags, we can allocate using the same
1167          * index size
1168          */
1169         istate->alloc = xmalloc(estimate_cache_size(mmap_size, istate->cache_nr));
1170
1171         src_offset = sizeof(*hdr);
1172         dst_offset = 0;
1173         for (i = 0; i < istate->cache_nr; i++) {
1174                 struct ondisk_cache_entry *disk_ce;
1175                 struct cache_entry *ce;
1176
1177                 disk_ce = (struct ondisk_cache_entry *)((char *)mmap + src_offset);
1178                 ce = (struct cache_entry *)((char *)istate->alloc + dst_offset);
1179                 convert_from_disk(disk_ce, ce);
1180                 set_index_entry(istate, i, ce);
1181
1182                 src_offset += ondisk_ce_size(ce);
1183                 dst_offset += ce_size(ce);
1184         }
1185         istate->timestamp = st.st_mtime;
1186         while (src_offset <= mmap_size - 20 - 8) {
1187                 /* After an array of active_nr index entries,
1188                  * there can be arbitrary number of extended
1189                  * sections, each of which is prefixed with
1190                  * extension name (4-byte) and section length
1191                  * in 4-byte network byte order.
1192                  */
1193                 unsigned long extsize;
1194                 memcpy(&extsize, (char *)mmap + src_offset + 4, 4);
1195                 extsize = ntohl(extsize);
1196                 if (read_index_extension(istate,
1197                                          (const char *) mmap + src_offset,
1198                                          (char *) mmap + src_offset + 8,
1199                                          extsize) < 0)
1200                         goto unmap;
1201                 src_offset += 8;
1202                 src_offset += extsize;
1203         }
1204         munmap(mmap, mmap_size);
1205         return istate->cache_nr;
1206
1207 unmap:
1208         munmap(mmap, mmap_size);
1209         errno = EINVAL;
1210         die("index file corrupt");
1211 }
1212
1213 int discard_index(struct index_state *istate)
1214 {
1215         istate->cache_nr = 0;
1216         istate->cache_changed = 0;
1217         istate->timestamp = 0;
1218         free_hash(&istate->name_hash);
1219         cache_tree_free(&(istate->cache_tree));
1220         free(istate->alloc);
1221         istate->alloc = NULL;
1222
1223         /* no need to throw away allocated active_cache */
1224         return 0;
1225 }
1226
1227 int unmerged_index(const struct index_state *istate)
1228 {
1229         int i;
1230         for (i = 0; i < istate->cache_nr; i++) {
1231                 if (ce_stage(istate->cache[i]))
1232                         return 1;
1233         }
1234         return 0;
1235 }
1236
1237 #define WRITE_BUFFER_SIZE 8192
1238 static unsigned char write_buffer[WRITE_BUFFER_SIZE];
1239 static unsigned long write_buffer_len;
1240
1241 static int ce_write_flush(SHA_CTX *context, int fd)
1242 {
1243         unsigned int buffered = write_buffer_len;
1244         if (buffered) {
1245                 SHA1_Update(context, write_buffer, buffered);
1246                 if (write_in_full(fd, write_buffer, buffered) != buffered)
1247                         return -1;
1248                 write_buffer_len = 0;
1249         }
1250         return 0;
1251 }
1252
1253 static int ce_write(SHA_CTX *context, int fd, void *data, unsigned int len)
1254 {
1255         while (len) {
1256                 unsigned int buffered = write_buffer_len;
1257                 unsigned int partial = WRITE_BUFFER_SIZE - buffered;
1258                 if (partial > len)
1259                         partial = len;
1260                 memcpy(write_buffer + buffered, data, partial);
1261                 buffered += partial;
1262                 if (buffered == WRITE_BUFFER_SIZE) {
1263                         write_buffer_len = buffered;
1264                         if (ce_write_flush(context, fd))
1265                                 return -1;
1266                         buffered = 0;
1267                 }
1268                 write_buffer_len = buffered;
1269                 len -= partial;
1270                 data = (char *) data + partial;
1271         }
1272         return 0;
1273 }
1274
1275 static int write_index_ext_header(SHA_CTX *context, int fd,
1276                                   unsigned int ext, unsigned int sz)
1277 {
1278         ext = htonl(ext);
1279         sz = htonl(sz);
1280         return ((ce_write(context, fd, &ext, 4) < 0) ||
1281                 (ce_write(context, fd, &sz, 4) < 0)) ? -1 : 0;
1282 }
1283
1284 static int ce_flush(SHA_CTX *context, int fd)
1285 {
1286         unsigned int left = write_buffer_len;
1287
1288         if (left) {
1289                 write_buffer_len = 0;
1290                 SHA1_Update(context, write_buffer, left);
1291         }
1292
1293         /* Flush first if not enough space for SHA1 signature */
1294         if (left + 20 > WRITE_BUFFER_SIZE) {
1295                 if (write_in_full(fd, write_buffer, left) != left)
1296                         return -1;
1297                 left = 0;
1298         }
1299
1300         /* Append the SHA1 signature at the end */
1301         SHA1_Final(write_buffer + left, context);
1302         left += 20;
1303         return (write_in_full(fd, write_buffer, left) != left) ? -1 : 0;
1304 }
1305
1306 static void ce_smudge_racily_clean_entry(struct cache_entry *ce)
1307 {
1308         /*
1309          * The only thing we care about in this function is to smudge the
1310          * falsely clean entry due to touch-update-touch race, so we leave
1311          * everything else as they are.  We are called for entries whose
1312          * ce_mtime match the index file mtime.
1313          */
1314         struct stat st;
1315
1316         if (lstat(ce->name, &st) < 0)
1317                 return;
1318         if (ce_match_stat_basic(ce, &st))
1319                 return;
1320         if (ce_modified_check_fs(ce, &st)) {
1321                 /* This is "racily clean"; smudge it.  Note that this
1322                  * is a tricky code.  At first glance, it may appear
1323                  * that it can break with this sequence:
1324                  *
1325                  * $ echo xyzzy >frotz
1326                  * $ git-update-index --add frotz
1327                  * $ : >frotz
1328                  * $ sleep 3
1329                  * $ echo filfre >nitfol
1330                  * $ git-update-index --add nitfol
1331                  *
1332                  * but it does not.  When the second update-index runs,
1333                  * it notices that the entry "frotz" has the same timestamp
1334                  * as index, and if we were to smudge it by resetting its
1335                  * size to zero here, then the object name recorded
1336                  * in index is the 6-byte file but the cached stat information
1337                  * becomes zero --- which would then match what we would
1338                  * obtain from the filesystem next time we stat("frotz").
1339                  *
1340                  * However, the second update-index, before calling
1341                  * this function, notices that the cached size is 6
1342                  * bytes and what is on the filesystem is an empty
1343                  * file, and never calls us, so the cached size information
1344                  * for "frotz" stays 6 which does not match the filesystem.
1345                  */
1346                 ce->ce_size = 0;
1347         }
1348 }
1349
1350 static int ce_write_entry(SHA_CTX *c, int fd, struct cache_entry *ce)
1351 {
1352         int size = ondisk_ce_size(ce);
1353         struct ondisk_cache_entry *ondisk = xcalloc(1, size);
1354
1355         ondisk->ctime.sec = htonl(ce->ce_ctime);
1356         ondisk->ctime.nsec = 0;
1357         ondisk->mtime.sec = htonl(ce->ce_mtime);
1358         ondisk->mtime.nsec = 0;
1359         ondisk->dev  = htonl(ce->ce_dev);
1360         ondisk->ino  = htonl(ce->ce_ino);
1361         ondisk->mode = htonl(ce->ce_mode);
1362         ondisk->uid  = htonl(ce->ce_uid);
1363         ondisk->gid  = htonl(ce->ce_gid);
1364         ondisk->size = htonl(ce->ce_size);
1365         hashcpy(ondisk->sha1, ce->sha1);
1366         ondisk->flags = htons(ce->ce_flags);
1367         memcpy(ondisk->name, ce->name, ce_namelen(ce));
1368
1369         return ce_write(c, fd, ondisk, size);
1370 }
1371
1372 int write_index(const struct index_state *istate, int newfd)
1373 {
1374         SHA_CTX c;
1375         struct cache_header hdr;
1376         int i, err, removed;
1377         struct cache_entry **cache = istate->cache;
1378         int entries = istate->cache_nr;
1379
1380         for (i = removed = 0; i < entries; i++)
1381                 if (cache[i]->ce_flags & CE_REMOVE)
1382                         removed++;
1383
1384         hdr.hdr_signature = htonl(CACHE_SIGNATURE);
1385         hdr.hdr_version = htonl(2);
1386         hdr.hdr_entries = htonl(entries - removed);
1387
1388         SHA1_Init(&c);
1389         if (ce_write(&c, newfd, &hdr, sizeof(hdr)) < 0)
1390                 return -1;
1391
1392         for (i = 0; i < entries; i++) {
1393                 struct cache_entry *ce = cache[i];
1394                 if (ce->ce_flags & CE_REMOVE)
1395                         continue;
1396                 if (!ce_uptodate(ce) && is_racy_timestamp(istate, ce))
1397                         ce_smudge_racily_clean_entry(ce);
1398                 if (ce_write_entry(&c, newfd, ce) < 0)
1399                         return -1;
1400         }
1401
1402         /* Write extension data here */
1403         if (istate->cache_tree) {
1404                 struct strbuf sb;
1405
1406                 strbuf_init(&sb, 0);
1407                 cache_tree_write(&sb, istate->cache_tree);
1408                 err = write_index_ext_header(&c, newfd, CACHE_EXT_TREE, sb.len) < 0
1409                         || ce_write(&c, newfd, sb.buf, sb.len) < 0;
1410                 strbuf_release(&sb);
1411                 if (err)
1412                         return -1;
1413         }
1414         return ce_flush(&c, newfd);
1415 }
1416
1417 /*
1418  * Read the index file that is potentially unmerged into given
1419  * index_state, dropping any unmerged entries.  Returns true is
1420  * the index is unmerged.  Callers who want to refuse to work
1421  * from an unmerged state can call this and check its return value,
1422  * instead of calling read_cache().
1423  */
1424 int read_index_unmerged(struct index_state *istate)
1425 {
1426         int i;
1427         struct cache_entry **dst;
1428         struct cache_entry *last = NULL;
1429
1430         read_index(istate);
1431         dst = istate->cache;
1432         for (i = 0; i < istate->cache_nr; i++) {
1433                 struct cache_entry *ce = istate->cache[i];
1434                 if (ce_stage(ce)) {
1435                         remove_name_hash(ce);
1436                         if (last && !strcmp(ce->name, last->name))
1437                                 continue;
1438                         cache_tree_invalidate_path(istate->cache_tree, ce->name);
1439                         last = ce;
1440                         continue;
1441                 }
1442                 *dst++ = ce;
1443         }
1444         istate->cache_nr = dst - istate->cache;
1445         return !!last;
1446 }