2 * GIT - The information manager from hell
4 * Copyright (C) Linus Torvalds, 2005
7 #include "cache-tree.h"
11 * The first letter should be 'A'..'Z' for extensions that are not
12 * necessary for a correct operation (i.e. optimization data).
13 * When new extensions are added that _needs_ to be understood in
14 * order to correctly interpret the index file, pick character that
15 * is outside the range, to cause the reader to abort.
18 #define CACHE_EXT(s) ( (s[0]<<24)|(s[1]<<16)|(s[2]<<8)|(s[3]) )
19 #define CACHE_EXT_TREE 0x54524545 /* "TREE" */
21 struct cache_entry
**active_cache
;
22 static time_t index_file_timestamp
;
23 unsigned int active_nr
, active_alloc
, active_cache_changed
;
25 struct cache_tree
*active_cache_tree
;
29 static void *cache_mmap
;
30 static size_t cache_mmap_size
;
33 * This only updates the "non-critical" parts of the directory
34 * cache, ie the parts that aren't tracked by GIT, and only used
35 * to validate the cache.
37 void fill_stat_cache_info(struct cache_entry
*ce
, struct stat
*st
)
39 ce
->ce_ctime
.sec
= htonl(st
->st_ctime
);
40 ce
->ce_mtime
.sec
= htonl(st
->st_mtime
);
42 ce
->ce_ctime
.nsec
= htonl(st
->st_ctim
.tv_nsec
);
43 ce
->ce_mtime
.nsec
= htonl(st
->st_mtim
.tv_nsec
);
45 ce
->ce_dev
= htonl(st
->st_dev
);
46 ce
->ce_ino
= htonl(st
->st_ino
);
47 ce
->ce_uid
= htonl(st
->st_uid
);
48 ce
->ce_gid
= htonl(st
->st_gid
);
49 ce
->ce_size
= htonl(st
->st_size
);
52 ce
->ce_flags
|= htons(CE_VALID
);
55 static int ce_compare_data(struct cache_entry
*ce
, struct stat
*st
)
58 int fd
= open(ce
->name
, O_RDONLY
);
61 unsigned char sha1
[20];
62 if (!index_fd(sha1
, fd
, st
, 0, OBJ_BLOB
, ce
->name
))
63 match
= hashcmp(sha1
, ce
->sha1
);
64 /* index_fd() closed the file descriptor already */
69 static int ce_compare_link(struct cache_entry
*ce
, size_t expected_size
)
75 enum object_type type
;
78 target
= xmalloc(expected_size
);
79 len
= readlink(ce
->name
, target
, expected_size
);
80 if (len
!= expected_size
) {
84 buffer
= read_sha1_file(ce
->sha1
, &type
, &size
);
89 if (size
== expected_size
)
90 match
= memcmp(buffer
, target
, size
);
96 static int ce_modified_check_fs(struct cache_entry
*ce
, struct stat
*st
)
98 switch (st
->st_mode
& S_IFMT
) {
100 if (ce_compare_data(ce
, st
))
104 if (ce_compare_link(ce
, xsize_t(st
->st_size
)))
113 static int ce_match_stat_basic(struct cache_entry
*ce
, struct stat
*st
)
115 unsigned int changed
= 0;
117 switch (ntohl(ce
->ce_mode
) & S_IFMT
) {
119 changed
|= !S_ISREG(st
->st_mode
) ? TYPE_CHANGED
: 0;
120 /* We consider only the owner x bit to be relevant for
123 if (trust_executable_bit
&&
124 (0100 & (ntohl(ce
->ce_mode
) ^ st
->st_mode
)))
125 changed
|= MODE_CHANGED
;
128 if (!S_ISLNK(st
->st_mode
) &&
129 (has_symlinks
|| !S_ISREG(st
->st_mode
)))
130 changed
|= TYPE_CHANGED
;
133 die("internal error: ce_mode is %o", ntohl(ce
->ce_mode
));
135 if (ce
->ce_mtime
.sec
!= htonl(st
->st_mtime
))
136 changed
|= MTIME_CHANGED
;
137 if (ce
->ce_ctime
.sec
!= htonl(st
->st_ctime
))
138 changed
|= CTIME_CHANGED
;
142 * nsec seems unreliable - not all filesystems support it, so
143 * as long as it is in the inode cache you get right nsec
144 * but after it gets flushed, you get zero nsec.
146 if (ce
->ce_mtime
.nsec
!= htonl(st
->st_mtim
.tv_nsec
))
147 changed
|= MTIME_CHANGED
;
148 if (ce
->ce_ctime
.nsec
!= htonl(st
->st_ctim
.tv_nsec
))
149 changed
|= CTIME_CHANGED
;
152 if (ce
->ce_uid
!= htonl(st
->st_uid
) ||
153 ce
->ce_gid
!= htonl(st
->st_gid
))
154 changed
|= OWNER_CHANGED
;
155 if (ce
->ce_ino
!= htonl(st
->st_ino
))
156 changed
|= INODE_CHANGED
;
160 * st_dev breaks on network filesystems where different
161 * clients will have different views of what "device"
162 * the filesystem is on
164 if (ce
->ce_dev
!= htonl(st
->st_dev
))
165 changed
|= INODE_CHANGED
;
168 if (ce
->ce_size
!= htonl(st
->st_size
))
169 changed
|= DATA_CHANGED
;
174 int ce_match_stat(struct cache_entry
*ce
, struct stat
*st
, int options
)
176 unsigned int changed
;
177 int ignore_valid
= options
& 01;
178 int assume_racy_is_modified
= options
& 02;
181 * If it's marked as always valid in the index, it's
182 * valid whatever the checked-out copy says.
184 if (!ignore_valid
&& (ce
->ce_flags
& htons(CE_VALID
)))
187 changed
= ce_match_stat_basic(ce
, st
);
190 * Within 1 second of this sequence:
191 * echo xyzzy >file && git-update-index --add file
192 * running this command:
194 * would give a falsely clean cache entry. The mtime and
195 * length match the cache, and other stat fields do not change.
197 * We could detect this at update-index time (the cache entry
198 * being registered/updated records the same time as "now")
199 * and delay the return from git-update-index, but that would
200 * effectively mean we can make at most one commit per second,
201 * which is not acceptable. Instead, we check cache entries
202 * whose mtime are the same as the index file timestamp more
203 * carefully than others.
206 index_file_timestamp
&&
207 index_file_timestamp
<= ntohl(ce
->ce_mtime
.sec
)) {
208 if (assume_racy_is_modified
)
209 changed
|= DATA_CHANGED
;
211 changed
|= ce_modified_check_fs(ce
, st
);
217 int ce_modified(struct cache_entry
*ce
, struct stat
*st
, int really
)
219 int changed
, changed_fs
;
220 changed
= ce_match_stat(ce
, st
, really
);
224 * If the mode or type has changed, there's no point in trying
225 * to refresh the entry - it's not going to match
227 if (changed
& (MODE_CHANGED
| TYPE_CHANGED
))
230 /* Immediately after read-tree or update-index --cacheinfo,
231 * the length field is zero. For other cases the ce_size
232 * should match the SHA1 recorded in the index entry.
234 if ((changed
& DATA_CHANGED
) && ce
->ce_size
!= htonl(0))
237 changed_fs
= ce_modified_check_fs(ce
, st
);
239 return changed
| changed_fs
;
243 int base_name_compare(const char *name1
, int len1
, int mode1
,
244 const char *name2
, int len2
, int mode2
)
246 unsigned char c1
, c2
;
247 int len
= len1
< len2
? len1
: len2
;
250 cmp
= memcmp(name1
, name2
, len
);
255 if (!c1
&& S_ISDIR(mode1
))
257 if (!c2
&& S_ISDIR(mode2
))
259 return (c1
< c2
) ? -1 : (c1
> c2
) ? 1 : 0;
262 int cache_name_compare(const char *name1
, int flags1
, const char *name2
, int flags2
)
264 int len1
= flags1
& CE_NAMEMASK
;
265 int len2
= flags2
& CE_NAMEMASK
;
266 int len
= len1
< len2
? len1
: len2
;
269 cmp
= memcmp(name1
, name2
, len
);
278 flags1
&= CE_STAGEMASK
;
279 flags2
&= CE_STAGEMASK
;
288 int cache_name_pos(const char *name
, int namelen
)
294 while (last
> first
) {
295 int next
= (last
+ first
) >> 1;
296 struct cache_entry
*ce
= active_cache
[next
];
297 int cmp
= cache_name_compare(name
, namelen
, ce
->name
, ntohs(ce
->ce_flags
));
309 /* Remove entry, return true if there are more entries to go.. */
310 int remove_cache_entry_at(int pos
)
312 active_cache_changed
= 1;
314 if (pos
>= active_nr
)
316 memmove(active_cache
+ pos
, active_cache
+ pos
+ 1, (active_nr
- pos
) * sizeof(struct cache_entry
*));
320 int remove_file_from_cache(const char *path
)
322 int pos
= cache_name_pos(path
, strlen(path
));
325 while (pos
< active_nr
&& !strcmp(active_cache
[pos
]->name
, path
))
326 remove_cache_entry_at(pos
);
330 int add_file_to_index(const char *path
, int verbose
)
334 struct cache_entry
*ce
;
336 if (lstat(path
, &st
))
337 die("%s: unable to stat (%s)", path
, strerror(errno
));
339 if (!S_ISREG(st
.st_mode
) && !S_ISLNK(st
.st_mode
))
340 die("%s: can only add regular files or symbolic links", path
);
342 namelen
= strlen(path
);
343 size
= cache_entry_size(namelen
);
344 ce
= xcalloc(1, size
);
345 memcpy(ce
->name
, path
, namelen
);
346 ce
->ce_flags
= htons(namelen
);
347 fill_stat_cache_info(ce
, &st
);
349 if (trust_executable_bit
&& has_symlinks
)
350 ce
->ce_mode
= create_ce_mode(st
.st_mode
);
352 /* If there is an existing entry, pick the mode bits and type
353 * from it, otherwise assume unexecutable regular file.
355 struct cache_entry
*ent
;
356 int pos
= cache_name_pos(path
, namelen
);
358 ent
= (0 <= pos
) ? active_cache
[pos
] : NULL
;
359 ce
->ce_mode
= ce_mode_from_stat(ent
, st
.st_mode
);
362 if (index_path(ce
->sha1
, path
, &st
, 1))
363 die("unable to index file %s", path
);
364 if (add_cache_entry(ce
, ADD_CACHE_OK_TO_ADD
|ADD_CACHE_OK_TO_REPLACE
))
365 die("unable to add %s to index",path
);
367 printf("add '%s'\n", path
);
368 cache_tree_invalidate_path(active_cache_tree
, path
);
372 int ce_same_name(struct cache_entry
*a
, struct cache_entry
*b
)
374 int len
= ce_namelen(a
);
375 return ce_namelen(b
) == len
&& !memcmp(a
->name
, b
->name
, len
);
378 int ce_path_match(const struct cache_entry
*ce
, const char **pathspec
)
380 const char *match
, *name
;
386 len
= ce_namelen(ce
);
388 while ((match
= *pathspec
++) != NULL
) {
389 int matchlen
= strlen(match
);
392 if (memcmp(name
, match
, matchlen
))
394 if (matchlen
&& name
[matchlen
-1] == '/')
396 if (name
[matchlen
] == '/' || !name
[matchlen
])
405 * We fundamentally don't like some paths: we don't want
406 * dot or dot-dot anywhere, and for obvious reasons don't
407 * want to recurse into ".git" either.
409 * Also, we don't want double slashes or slashes at the
410 * end that can make pathnames ambiguous.
412 static int verify_dotfile(const char *rest
)
415 * The first character was '.', but that
416 * has already been discarded, we now test
420 /* "." is not allowed */
425 * ".git" followed by NUL or slash is bad. This
426 * shares the path end test with the ".." case.
436 if (rest
[1] == '\0' || rest
[1] == '/')
442 int verify_path(const char *path
)
459 if (verify_dotfile(path
))
469 * Do we have another file that has the beginning components being a
470 * proper superset of the name we're trying to add?
472 static int has_file_name(const struct cache_entry
*ce
, int pos
, int ok_to_replace
)
475 int len
= ce_namelen(ce
);
476 int stage
= ce_stage(ce
);
477 const char *name
= ce
->name
;
479 while (pos
< active_nr
) {
480 struct cache_entry
*p
= active_cache
[pos
++];
482 if (len
>= ce_namelen(p
))
484 if (memcmp(name
, p
->name
, len
))
486 if (ce_stage(p
) != stage
)
488 if (p
->name
[len
] != '/')
490 if (!ce_stage(p
) && !p
->ce_mode
)
495 remove_cache_entry_at(--pos
);
501 * Do we have another file with a pathname that is a proper
502 * subset of the name we're trying to add?
504 static int has_dir_name(const struct cache_entry
*ce
, int pos
, int ok_to_replace
)
507 int stage
= ce_stage(ce
);
508 const char *name
= ce
->name
;
509 const char *slash
= name
+ ce_namelen(ce
);
517 if (slash
<= ce
->name
)
522 pos
= cache_name_pos(name
, ntohs(create_ce_flags(len
, stage
)));
525 * Found one, but not so fast. This could
526 * be a marker that says "I was here, but
527 * I am being removed". Such an entry is
528 * not a part of the resulting tree, and
529 * it is Ok to have a directory at the same
532 if (stage
|| active_cache
[pos
]->ce_mode
) {
536 remove_cache_entry_at(pos
);
544 * Trivial optimization: if we find an entry that
545 * already matches the sub-directory, then we know
546 * we're ok, and we can exit.
548 while (pos
< active_nr
) {
549 struct cache_entry
*p
= active_cache
[pos
];
550 if ((ce_namelen(p
) <= len
) ||
551 (p
->name
[len
] != '/') ||
552 memcmp(p
->name
, name
, len
))
553 break; /* not our subdirectory */
554 if (ce_stage(p
) == stage
&& (stage
|| p
->ce_mode
))
555 /* p is at the same stage as our entry, and
556 * is a subdirectory of what we are looking
557 * at, so we cannot have conflicts at our
558 * level or anything shorter.
567 /* We may be in a situation where we already have path/file and path
568 * is being added, or we already have path and path/file is being
569 * added. Either one would result in a nonsense tree that has path
570 * twice when git-write-tree tries to write it out. Prevent it.
572 * If ok-to-replace is specified, we remove the conflicting entries
573 * from the cache so the caller should recompute the insert position.
574 * When this happens, we return non-zero.
576 static int check_file_directory_conflict(const struct cache_entry
*ce
, int pos
, int ok_to_replace
)
581 * When ce is an "I am going away" entry, we allow it to be added
583 if (!ce_stage(ce
) && !ce
->ce_mode
)
587 * We check if the path is a sub-path of a subsequent pathname
588 * first, since removing those will not change the position
591 retval
= has_file_name(ce
, pos
, ok_to_replace
);
594 * Then check if the path might have a clashing sub-directory
597 return retval
+ has_dir_name(ce
, pos
, ok_to_replace
);
600 int add_cache_entry(struct cache_entry
*ce
, int option
)
603 int ok_to_add
= option
& ADD_CACHE_OK_TO_ADD
;
604 int ok_to_replace
= option
& ADD_CACHE_OK_TO_REPLACE
;
605 int skip_df_check
= option
& ADD_CACHE_SKIP_DFCHECK
;
607 pos
= cache_name_pos(ce
->name
, ntohs(ce
->ce_flags
));
609 /* existing match? Just replace it. */
611 active_cache_changed
= 1;
612 active_cache
[pos
] = ce
;
618 * Inserting a merged entry ("stage 0") into the index
619 * will always replace all non-merged entries..
621 if (pos
< active_nr
&& ce_stage(ce
) == 0) {
622 while (ce_same_name(active_cache
[pos
], ce
)) {
624 if (!remove_cache_entry_at(pos
))
631 if (!verify_path(ce
->name
))
634 if (!skip_df_check
&&
635 check_file_directory_conflict(ce
, pos
, ok_to_replace
)) {
637 return error("'%s' appears as both a file and as a directory", ce
->name
);
638 pos
= cache_name_pos(ce
->name
, ntohs(ce
->ce_flags
));
642 /* Make sure the array is big enough .. */
643 if (active_nr
== active_alloc
) {
644 active_alloc
= alloc_nr(active_alloc
);
645 active_cache
= xrealloc(active_cache
, active_alloc
* sizeof(struct cache_entry
*));
651 memmove(active_cache
+ pos
+ 1, active_cache
+ pos
, (active_nr
- pos
- 1) * sizeof(ce
));
652 active_cache
[pos
] = ce
;
653 active_cache_changed
= 1;
658 * "refresh" does not calculate a new sha1 file or bring the
659 * cache up-to-date for mode/content changes. But what it
660 * _does_ do is to "re-match" the stat information of a file
661 * with the cache, so that you can refresh the cache for a
662 * file that hasn't been changed but where the stat entry is
665 * For example, you'd want to do this after doing a "git-read-tree",
666 * to link up the stat cache details with the proper files.
668 struct cache_entry
*refresh_cache_entry(struct cache_entry
*ce
, int really
)
671 struct cache_entry
*updated
;
674 if (lstat(ce
->name
, &st
) < 0) {
679 changed
= ce_match_stat(ce
, &st
, really
);
681 if (really
&& assume_unchanged
&&
682 !(ce
->ce_flags
& htons(CE_VALID
)))
683 ; /* mark this one VALID again */
688 if (ce_modified(ce
, &st
, really
)) {
689 cache_errno
= EINVAL
;
694 updated
= xmalloc(size
);
695 memcpy(updated
, ce
, size
);
696 fill_stat_cache_info(updated
, &st
);
698 /* In this case, if really is not set, we should leave
699 * CE_VALID bit alone. Otherwise, paths marked with
700 * --no-assume-unchanged (i.e. things to be edited) will
701 * reacquire CE_VALID bit automatically, which is not
702 * really what we want.
704 if (!really
&& assume_unchanged
&& !(ce
->ce_flags
& htons(CE_VALID
)))
705 updated
->ce_flags
&= ~htons(CE_VALID
);
710 int refresh_cache(unsigned int flags
)
714 int really
= (flags
& REFRESH_REALLY
) != 0;
715 int allow_unmerged
= (flags
& REFRESH_UNMERGED
) != 0;
716 int quiet
= (flags
& REFRESH_QUIET
) != 0;
717 int not_new
= (flags
& REFRESH_IGNORE_MISSING
) != 0;
719 for (i
= 0; i
< active_nr
; i
++) {
720 struct cache_entry
*ce
, *new;
721 ce
= active_cache
[i
];
723 while ((i
< active_nr
) &&
724 ! strcmp(active_cache
[i
]->name
, ce
->name
))
729 printf("%s: needs merge\n", ce
->name
);
734 new = refresh_cache_entry(ce
, really
);
738 if (not_new
&& cache_errno
== ENOENT
)
740 if (really
&& cache_errno
== EINVAL
) {
741 /* If we are doing --really-refresh that
742 * means the index is not valid anymore.
744 ce
->ce_flags
&= ~htons(CE_VALID
);
745 active_cache_changed
= 1;
749 printf("%s: needs update\n", ce
->name
);
753 active_cache_changed
= 1;
754 /* You can NOT just free active_cache[i] here, since it
755 * might not be necessarily malloc()ed but can also come
757 active_cache
[i
] = new;
762 static int verify_hdr(struct cache_header
*hdr
, unsigned long size
)
765 unsigned char sha1
[20];
767 if (hdr
->hdr_signature
!= htonl(CACHE_SIGNATURE
))
768 return error("bad signature");
769 if (hdr
->hdr_version
!= htonl(2))
770 return error("bad index version");
772 SHA1_Update(&c
, hdr
, size
- 20);
773 SHA1_Final(sha1
, &c
);
774 if (hashcmp(sha1
, (unsigned char *)hdr
+ size
- 20))
775 return error("bad index file sha1 signature");
779 static int read_index_extension(const char *ext
, void *data
, unsigned long sz
)
781 switch (CACHE_EXT(ext
)) {
783 active_cache_tree
= cache_tree_read(data
, sz
);
786 if (*ext
< 'A' || 'Z' < *ext
)
787 return error("index uses %.4s extension, which we do not understand",
789 fprintf(stderr
, "ignoring %.4s extension\n", ext
);
797 return read_cache_from(get_index_file());
800 /* remember to discard_cache() before reading a different cache! */
801 int read_cache_from(const char *path
)
805 unsigned long offset
;
806 struct cache_header
*hdr
;
813 index_file_timestamp
= 0;
814 fd
= open(path
, O_RDONLY
);
818 die("index file open failed (%s)", strerror(errno
));
821 if (!fstat(fd
, &st
)) {
822 cache_mmap_size
= xsize_t(st
.st_size
);
824 if (cache_mmap_size
>= sizeof(struct cache_header
) + 20)
825 cache_mmap
= xmmap(NULL
, cache_mmap_size
, PROT_READ
| PROT_WRITE
, MAP_PRIVATE
, fd
, 0);
827 die("index file smaller than expected");
829 die("cannot stat the open index (%s)", strerror(errno
));
833 if (verify_hdr(hdr
, cache_mmap_size
) < 0)
836 active_nr
= ntohl(hdr
->hdr_entries
);
837 active_alloc
= alloc_nr(active_nr
);
838 active_cache
= xcalloc(active_alloc
, sizeof(struct cache_entry
*));
840 offset
= sizeof(*hdr
);
841 for (i
= 0; i
< active_nr
; i
++) {
842 struct cache_entry
*ce
= (struct cache_entry
*) ((char *) cache_mmap
+ offset
);
843 offset
= offset
+ ce_size(ce
);
844 active_cache
[i
] = ce
;
846 index_file_timestamp
= st
.st_mtime
;
847 while (offset
<= cache_mmap_size
- 20 - 8) {
848 /* After an array of active_nr index entries,
849 * there can be arbitrary number of extended
850 * sections, each of which is prefixed with
851 * extension name (4-byte) and section length
852 * in 4-byte network byte order.
854 unsigned long extsize
;
855 memcpy(&extsize
, (char *) cache_mmap
+ offset
+ 4, 4);
856 extsize
= ntohl(extsize
);
857 if (read_index_extension(((const char *) cache_mmap
) + offset
,
858 (char *) cache_mmap
+ offset
+ 8,
867 munmap(cache_mmap
, cache_mmap_size
);
869 die("index file corrupt");
872 int discard_cache(void)
876 active_nr
= active_cache_changed
= 0;
877 index_file_timestamp
= 0;
878 cache_tree_free(&active_cache_tree
);
879 if (cache_mmap
== NULL
)
881 ret
= munmap(cache_mmap
, cache_mmap_size
);
885 /* no need to throw away allocated active_cache */
889 #define WRITE_BUFFER_SIZE 8192
890 static unsigned char write_buffer
[WRITE_BUFFER_SIZE
];
891 static unsigned long write_buffer_len
;
893 static int ce_write_flush(SHA_CTX
*context
, int fd
)
895 unsigned int buffered
= write_buffer_len
;
897 SHA1_Update(context
, write_buffer
, buffered
);
898 if (write_in_full(fd
, write_buffer
, buffered
) != buffered
)
900 write_buffer_len
= 0;
905 static int ce_write(SHA_CTX
*context
, int fd
, void *data
, unsigned int len
)
908 unsigned int buffered
= write_buffer_len
;
909 unsigned int partial
= WRITE_BUFFER_SIZE
- buffered
;
912 memcpy(write_buffer
+ buffered
, data
, partial
);
914 if (buffered
== WRITE_BUFFER_SIZE
) {
915 write_buffer_len
= buffered
;
916 if (ce_write_flush(context
, fd
))
920 write_buffer_len
= buffered
;
922 data
= (char *) data
+ partial
;
927 static int write_index_ext_header(SHA_CTX
*context
, int fd
,
928 unsigned int ext
, unsigned int sz
)
932 return ((ce_write(context
, fd
, &ext
, 4) < 0) ||
933 (ce_write(context
, fd
, &sz
, 4) < 0)) ? -1 : 0;
936 static int ce_flush(SHA_CTX
*context
, int fd
)
938 unsigned int left
= write_buffer_len
;
941 write_buffer_len
= 0;
942 SHA1_Update(context
, write_buffer
, left
);
945 /* Flush first if not enough space for SHA1 signature */
946 if (left
+ 20 > WRITE_BUFFER_SIZE
) {
947 if (write_in_full(fd
, write_buffer
, left
) != left
)
952 /* Append the SHA1 signature at the end */
953 SHA1_Final(write_buffer
+ left
, context
);
955 return (write_in_full(fd
, write_buffer
, left
) != left
) ? -1 : 0;
958 static void ce_smudge_racily_clean_entry(struct cache_entry
*ce
)
961 * The only thing we care about in this function is to smudge the
962 * falsely clean entry due to touch-update-touch race, so we leave
963 * everything else as they are. We are called for entries whose
964 * ce_mtime match the index file mtime.
968 if (lstat(ce
->name
, &st
) < 0)
970 if (ce_match_stat_basic(ce
, &st
))
972 if (ce_modified_check_fs(ce
, &st
)) {
973 /* This is "racily clean"; smudge it. Note that this
974 * is a tricky code. At first glance, it may appear
975 * that it can break with this sequence:
977 * $ echo xyzzy >frotz
978 * $ git-update-index --add frotz
981 * $ echo filfre >nitfol
982 * $ git-update-index --add nitfol
984 * but it does not. When the second update-index runs,
985 * it notices that the entry "frotz" has the same timestamp
986 * as index, and if we were to smudge it by resetting its
987 * size to zero here, then the object name recorded
988 * in index is the 6-byte file but the cached stat information
989 * becomes zero --- which would then match what we would
990 * obtain from the filesystem next time we stat("frotz").
992 * However, the second update-index, before calling
993 * this function, notices that the cached size is 6
994 * bytes and what is on the filesystem is an empty
995 * file, and never calls us, so the cached size information
996 * for "frotz" stays 6 which does not match the filesystem.
998 ce
->ce_size
= htonl(0);
1002 int write_cache(int newfd
, struct cache_entry
**cache
, int entries
)
1005 struct cache_header hdr
;
1008 for (i
= removed
= 0; i
< entries
; i
++)
1009 if (!cache
[i
]->ce_mode
)
1012 hdr
.hdr_signature
= htonl(CACHE_SIGNATURE
);
1013 hdr
.hdr_version
= htonl(2);
1014 hdr
.hdr_entries
= htonl(entries
- removed
);
1017 if (ce_write(&c
, newfd
, &hdr
, sizeof(hdr
)) < 0)
1020 for (i
= 0; i
< entries
; i
++) {
1021 struct cache_entry
*ce
= cache
[i
];
1024 if (index_file_timestamp
&&
1025 index_file_timestamp
<= ntohl(ce
->ce_mtime
.sec
))
1026 ce_smudge_racily_clean_entry(ce
);
1027 if (ce_write(&c
, newfd
, ce
, ce_size(ce
)) < 0)
1031 /* Write extension data here */
1032 if (active_cache_tree
) {
1034 void *data
= cache_tree_write(active_cache_tree
, &sz
);
1036 !write_index_ext_header(&c
, newfd
, CACHE_EXT_TREE
, sz
) &&
1037 !ce_write(&c
, newfd
, data
, sz
))
1044 return ce_flush(&c
, newfd
);