2 * GIT - The information manager from hell
4 * Copyright (C) Linus Torvalds, 2005
8 struct cache_entry **active_cache = NULL;
9 static time_t index_file_timestamp;
10 unsigned int active_nr = 0, active_alloc = 0, active_cache_changed = 0;
13 * This only updates the "non-critical" parts of the directory
14 * cache, ie the parts that aren't tracked by GIT, and only used
15 * to validate the cache.
17 void fill_stat_cache_info(struct cache_entry *ce, struct stat *st)
19 ce->ce_ctime.sec = htonl(st->st_ctime);
20 ce->ce_mtime.sec = htonl(st->st_mtime);
22 ce->ce_ctime.nsec = htonl(st->st_ctim.tv_nsec);
23 ce->ce_mtime.nsec = htonl(st->st_mtim.tv_nsec);
25 ce->ce_dev = htonl(st->st_dev);
26 ce->ce_ino = htonl(st->st_ino);
27 ce->ce_uid = htonl(st->st_uid);
28 ce->ce_gid = htonl(st->st_gid);
29 ce->ce_size = htonl(st->st_size);
32 static int ce_compare_data(struct cache_entry *ce, struct stat *st)
35 int fd = open(ce->name, O_RDONLY);
38 unsigned char sha1[20];
39 if (!index_fd(sha1, fd, st, 0, NULL))
40 match = memcmp(sha1, ce->sha1, 20);
46 static int ce_compare_link(struct cache_entry *ce, unsigned long expected_size)
55 target = xmalloc(expected_size);
56 len = readlink(ce->name, target, expected_size);
57 if (len != expected_size) {
61 buffer = read_sha1_file(ce->sha1, type, &size);
66 if (size == expected_size)
67 match = memcmp(buffer, target, size);
73 static int ce_modified_check_fs(struct cache_entry *ce, struct stat *st)
75 switch (st->st_mode & S_IFMT) {
77 if (ce_compare_data(ce, st))
81 if (ce_compare_link(ce, st->st_size))
90 int ce_match_stat(struct cache_entry *ce, struct stat *st)
92 unsigned int changed = 0;
94 switch (ntohl(ce->ce_mode) & S_IFMT) {
96 changed |= !S_ISREG(st->st_mode) ? TYPE_CHANGED : 0;
97 /* We consider only the owner x bit to be relevant for
100 if (trust_executable_bit &&
101 (0100 & (ntohl(ce->ce_mode) ^ st->st_mode)))
102 changed |= MODE_CHANGED;
105 changed |= !S_ISLNK(st->st_mode) ? TYPE_CHANGED : 0;
108 die("internal error: ce_mode is %o", ntohl(ce->ce_mode));
110 if (ce->ce_mtime.sec != htonl(st->st_mtime))
111 changed |= MTIME_CHANGED;
112 if (ce->ce_ctime.sec != htonl(st->st_ctime))
113 changed |= CTIME_CHANGED;
117 * nsec seems unreliable - not all filesystems support it, so
118 * as long as it is in the inode cache you get right nsec
119 * but after it gets flushed, you get zero nsec.
121 if (ce->ce_mtime.nsec != htonl(st->st_mtim.tv_nsec))
122 changed |= MTIME_CHANGED;
123 if (ce->ce_ctime.nsec != htonl(st->st_ctim.tv_nsec))
124 changed |= CTIME_CHANGED;
127 if (ce->ce_uid != htonl(st->st_uid) ||
128 ce->ce_gid != htonl(st->st_gid))
129 changed |= OWNER_CHANGED;
130 if (ce->ce_ino != htonl(st->st_ino))
131 changed |= INODE_CHANGED;
135 * st_dev breaks on network filesystems where different
136 * clients will have different views of what "device"
137 * the filesystem is on
139 if (ce->ce_dev != htonl(st->st_dev))
140 changed |= INODE_CHANGED;
143 if (ce->ce_size != htonl(st->st_size))
144 changed |= DATA_CHANGED;
147 * Within 1 second of this sequence:
148 * echo xyzzy >file && git-update-index --add file
149 * running this command:
151 * would give a falsely clean cache entry. The mtime and
152 * length match the cache, and other stat fields do not change.
154 * We could detect this at update-index time (the cache entry
155 * being registered/updated records the same time as "now")
156 * and delay the return from git-update-index, but that would
157 * effectively mean we can make at most one commit per second,
158 * which is not acceptable. Instead, we check cache entries
159 * whose mtime are the same as the index file timestamp more
160 * careful than others.
163 index_file_timestamp &&
164 index_file_timestamp <= ntohl(ce->ce_mtime.sec))
165 changed |= ce_modified_check_fs(ce, st);
170 int ce_modified(struct cache_entry *ce, struct stat *st)
172 int changed, changed_fs;
173 changed = ce_match_stat(ce, st);
177 * If the mode or type has changed, there's no point in trying
178 * to refresh the entry - it's not going to match
180 if (changed & (MODE_CHANGED | TYPE_CHANGED))
183 /* Immediately after read-tree or update-index --cacheinfo,
184 * the length field is zero. For other cases the ce_size
185 * should match the SHA1 recorded in the index entry.
187 if ((changed & DATA_CHANGED) && ce->ce_size != htonl(0))
190 changed_fs = ce_modified_check_fs(ce, st);
192 return changed | changed_fs;
196 int base_name_compare(const char *name1, int len1, int mode1,
197 const char *name2, int len2, int mode2)
199 unsigned char c1, c2;
200 int len = len1 < len2 ? len1 : len2;
203 cmp = memcmp(name1, name2, len);
208 if (!c1 && S_ISDIR(mode1))
210 if (!c2 && S_ISDIR(mode2))
212 return (c1 < c2) ? -1 : (c1 > c2) ? 1 : 0;
215 int cache_name_compare(const char *name1, int flags1, const char *name2, int flags2)
217 int len1 = flags1 & CE_NAMEMASK;
218 int len2 = flags2 & CE_NAMEMASK;
219 int len = len1 < len2 ? len1 : len2;
222 cmp = memcmp(name1, name2, len);
236 int cache_name_pos(const char *name, int namelen)
242 while (last > first) {
243 int next = (last + first) >> 1;
244 struct cache_entry *ce = active_cache[next];
245 int cmp = cache_name_compare(name, namelen, ce->name, ntohs(ce->ce_flags));
257 /* Remove entry, return true if there are more entries to go.. */
258 int remove_cache_entry_at(int pos)
260 active_cache_changed = 1;
262 if (pos >= active_nr)
264 memmove(active_cache + pos, active_cache + pos + 1, (active_nr - pos) * sizeof(struct cache_entry *));
268 int remove_file_from_cache(const char *path)
270 int pos = cache_name_pos(path, strlen(path));
273 while (pos < active_nr && !strcmp(active_cache[pos]->name, path))
274 remove_cache_entry_at(pos);
278 int ce_same_name(struct cache_entry *a, struct cache_entry *b)
280 int len = ce_namelen(a);
281 return ce_namelen(b) == len && !memcmp(a->name, b->name, len);
284 int ce_path_match(const struct cache_entry *ce, const char **pathspec)
286 const char *match, *name;
292 len = ce_namelen(ce);
294 while ((match = *pathspec++) != NULL) {
295 int matchlen = strlen(match);
298 if (memcmp(name, match, matchlen))
300 if (matchlen && name[matchlen-1] == '/')
302 if (name[matchlen] == '/' || !name[matchlen])
311 * Do we have another file that has the beginning components being a
312 * proper superset of the name we're trying to add?
314 static int has_file_name(const struct cache_entry *ce, int pos, int ok_to_replace)
317 int len = ce_namelen(ce);
318 int stage = ce_stage(ce);
319 const char *name = ce->name;
321 while (pos < active_nr) {
322 struct cache_entry *p = active_cache[pos++];
324 if (len >= ce_namelen(p))
326 if (memcmp(name, p->name, len))
328 if (ce_stage(p) != stage)
330 if (p->name[len] != '/')
335 remove_cache_entry_at(--pos);
341 * Do we have another file with a pathname that is a proper
342 * subset of the name we're trying to add?
344 static int has_dir_name(const struct cache_entry *ce, int pos, int ok_to_replace)
347 int stage = ce_stage(ce);
348 const char *name = ce->name;
349 const char *slash = name + ce_namelen(ce);
357 if (slash <= ce->name)
362 pos = cache_name_pos(name, ntohs(create_ce_flags(len, stage)));
367 remove_cache_entry_at(pos);
372 * Trivial optimization: if we find an entry that
373 * already matches the sub-directory, then we know
374 * we're ok, and we can exit.
377 while (pos < active_nr) {
378 struct cache_entry *p = active_cache[pos];
379 if ((ce_namelen(p) <= len) ||
380 (p->name[len] != '/') ||
381 memcmp(p->name, name, len))
382 break; /* not our subdirectory */
383 if (ce_stage(p) == stage)
384 /* p is at the same stage as our entry, and
385 * is a subdirectory of what we are looking
386 * at, so we cannot have conflicts at our
387 * level or anything shorter.
396 /* We may be in a situation where we already have path/file and path
397 * is being added, or we already have path and path/file is being
398 * added. Either one would result in a nonsense tree that has path
399 * twice when git-write-tree tries to write it out. Prevent it.
401 * If ok-to-replace is specified, we remove the conflicting entries
402 * from the cache so the caller should recompute the insert position.
403 * When this happens, we return non-zero.
405 static int check_file_directory_conflict(const struct cache_entry *ce, int pos, int ok_to_replace)
408 * We check if the path is a sub-path of a subsequent pathname
409 * first, since removing those will not change the position
412 int retval = has_file_name(ce, pos, ok_to_replace);
414 * Then check if the path might have a clashing sub-directory
417 return retval + has_dir_name(ce, pos, ok_to_replace);
420 int add_cache_entry(struct cache_entry *ce, int option)
423 int ok_to_add = option & ADD_CACHE_OK_TO_ADD;
424 int ok_to_replace = option & ADD_CACHE_OK_TO_REPLACE;
425 int skip_df_check = option & ADD_CACHE_SKIP_DFCHECK;
426 pos = cache_name_pos(ce->name, ntohs(ce->ce_flags));
428 /* existing match? Just replace it. */
430 active_cache_changed = 1;
431 active_cache[pos] = ce;
437 * Inserting a merged entry ("stage 0") into the index
438 * will always replace all non-merged entries..
440 if (pos < active_nr && ce_stage(ce) == 0) {
441 while (ce_same_name(active_cache[pos], ce)) {
443 if (!remove_cache_entry_at(pos))
451 if (!skip_df_check &&
452 check_file_directory_conflict(ce, pos, ok_to_replace)) {
455 pos = cache_name_pos(ce->name, ntohs(ce->ce_flags));
459 /* Make sure the array is big enough .. */
460 if (active_nr == active_alloc) {
461 active_alloc = alloc_nr(active_alloc);
462 active_cache = xrealloc(active_cache, active_alloc * sizeof(struct cache_entry *));
468 memmove(active_cache + pos + 1, active_cache + pos, (active_nr - pos - 1) * sizeof(ce));
469 active_cache[pos] = ce;
470 active_cache_changed = 1;
474 static int verify_hdr(struct cache_header *hdr, unsigned long size)
477 unsigned char sha1[20];
479 if (hdr->hdr_signature != htonl(CACHE_SIGNATURE))
480 return error("bad signature");
481 if (hdr->hdr_version != htonl(2))
482 return error("bad index version");
484 SHA1_Update(&c, hdr, size - 20);
485 SHA1_Final(sha1, &c);
486 if (memcmp(sha1, (void *)hdr + size - 20, 20))
487 return error("bad index file sha1 signature");
495 unsigned long size, offset;
497 struct cache_header *hdr;
504 index_file_timestamp = 0;
505 fd = open(get_index_file(), O_RDONLY);
509 die("index file open failed (%s)", strerror(errno));
512 size = 0; // avoid gcc warning
514 if (!fstat(fd, &st)) {
517 if (size >= sizeof(struct cache_header) + 20)
518 map = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
521 if (map == MAP_FAILED)
522 die("index file mmap failed (%s)", strerror(errno));
525 if (verify_hdr(hdr, size) < 0)
528 active_nr = ntohl(hdr->hdr_entries);
529 active_alloc = alloc_nr(active_nr);
530 active_cache = calloc(active_alloc, sizeof(struct cache_entry *));
532 offset = sizeof(*hdr);
533 for (i = 0; i < active_nr; i++) {
534 struct cache_entry *ce = map + offset;
535 offset = offset + ce_size(ce);
536 active_cache[i] = ce;
538 index_file_timestamp = st.st_mtime;
544 die("index file corrupt");
547 #define WRITE_BUFFER_SIZE 8192
548 static unsigned char write_buffer[WRITE_BUFFER_SIZE];
549 static unsigned long write_buffer_len;
551 static int ce_write(SHA_CTX *context, int fd, void *data, unsigned int len)
554 unsigned int buffered = write_buffer_len;
555 unsigned int partial = WRITE_BUFFER_SIZE - buffered;
558 memcpy(write_buffer + buffered, data, partial);
560 if (buffered == WRITE_BUFFER_SIZE) {
561 SHA1_Update(context, write_buffer, WRITE_BUFFER_SIZE);
562 if (write(fd, write_buffer, WRITE_BUFFER_SIZE) != WRITE_BUFFER_SIZE)
566 write_buffer_len = buffered;
573 static int ce_flush(SHA_CTX *context, int fd)
575 unsigned int left = write_buffer_len;
578 write_buffer_len = 0;
579 SHA1_Update(context, write_buffer, left);
582 /* Flush first if not enough space for SHA1 signature */
583 if (left + 20 > WRITE_BUFFER_SIZE) {
584 if (write(fd, write_buffer, left) != left)
589 /* Append the SHA1 signature at the end */
590 SHA1_Final(write_buffer + left, context);
592 if (write(fd, write_buffer, left) != left)
597 int write_cache(int newfd, struct cache_entry **cache, int entries)
600 struct cache_header hdr;
603 for (i = removed = 0; i < entries; i++)
604 if (!cache[i]->ce_mode)
607 hdr.hdr_signature = htonl(CACHE_SIGNATURE);
608 hdr.hdr_version = htonl(2);
609 hdr.hdr_entries = htonl(entries - removed);
612 if (ce_write(&c, newfd, &hdr, sizeof(hdr)) < 0)
615 for (i = 0; i < entries; i++) {
616 struct cache_entry *ce = cache[i];
619 if (ce_write(&c, newfd, ce, ce_size(ce)) < 0)
622 return ce_flush(&c, newfd);