*
* Copyright (C) Linus Torvalds, 2005
*/
-#include <stdarg.h>
#include "cache.h"
-const char *sha1_file_directory = NULL;
struct cache_entry **active_cache = NULL;
-unsigned int active_nr = 0, active_alloc = 0;
-
-void usage(const char *err)
-{
- fprintf(stderr, "usage: %s\n", err);
- exit(1);
-}
-
-static void report(const char *prefix, const char *err, va_list params)
-{
- fputs(prefix, stderr);
- vfprintf(stderr, err, params);
- fputs("\n", stderr);
-}
-
-void die(const char *err, ...)
-{
- va_list params;
-
- va_start(params, err);
- report("fatal: ", err, params);
- va_end(params);
- exit(1);
-}
-
-int error(const char *err, ...)
-{
- va_list params;
-
- va_start(params, err);
- report("error: ", err, params);
- va_end(params);
- return -1;
-}
-
-
-static unsigned hexval(char c)
-{
- if (c >= '0' && c <= '9')
- return c - '0';
- if (c >= 'a' && c <= 'f')
- return c - 'a' + 10;
- if (c >= 'A' && c <= 'F')
- return c - 'A' + 10;
- return ~0;
-}
-
-int get_sha1_hex(const char *hex, unsigned char *sha1)
-{
- int i;
- for (i = 0; i < 20; i++) {
- unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
- if (val & ~0xff)
- return -1;
- *sha1++ = val;
- hex += 2;
- }
- return 0;
-}
-
-char * sha1_to_hex(const unsigned char *sha1)
-{
- static char buffer[50];
- static const char hex[] = "0123456789abcdef";
- char *buf = buffer;
- int i;
-
- for (i = 0; i < 20; i++) {
- unsigned int val = *sha1++;
- *buf++ = hex[val >> 4];
- *buf++ = hex[val & 0xf];
- }
- return buffer;
-}
+static time_t index_file_timestamp;
+unsigned int active_nr = 0, active_alloc = 0, active_cache_changed = 0;
/*
- * NOTE! This returns a statically allocated buffer, so you have to be
- * careful about using it. Do a "strdup()" if you need to save the
- * filename.
+ * This only updates the "non-critical" parts of the directory
+ * cache, ie the parts that aren't tracked by GIT, and only used
+ * to validate the cache.
*/
-char *sha1_file_name(const unsigned char *sha1)
-{
- int i;
- static char *name, *base;
-
- if (!base) {
- char *sha1_file_directory = getenv(DB_ENVIRONMENT) ? : DEFAULT_DB_ENVIRONMENT;
- int len = strlen(sha1_file_directory);
- base = malloc(len + 60);
- memcpy(base, sha1_file_directory, len);
- memset(base+len, 0, 60);
- base[len] = '/';
- base[len+3] = '/';
- name = base + len + 1;
- }
- for (i = 0; i < 20; i++) {
- static char hex[] = "0123456789abcdef";
- unsigned int val = sha1[i];
- char *pos = name + i*2 + (i > 0);
- *pos++ = hex[val >> 4];
- *pos = hex[val & 0xf];
- }
- return base;
-}
-
-int check_sha1_signature(unsigned char *sha1, void *map, unsigned long size)
+void fill_stat_cache_info(struct cache_entry *ce, struct stat *st)
{
- unsigned char real_sha1[20];
- SHA_CTX c;
-
- SHA1_Init(&c);
- SHA1_Update(&c, map, size);
- SHA1_Final(real_sha1, &c);
- return memcmp(sha1, real_sha1, 20) ? -1 : 0;
+ ce->ce_ctime.sec = htonl(st->st_ctime);
+ ce->ce_mtime.sec = htonl(st->st_mtime);
+#ifdef USE_NSEC
+ ce->ce_ctime.nsec = htonl(st->st_ctim.tv_nsec);
+ ce->ce_mtime.nsec = htonl(st->st_mtim.tv_nsec);
+#endif
+ ce->ce_dev = htonl(st->st_dev);
+ ce->ce_ino = htonl(st->st_ino);
+ ce->ce_uid = htonl(st->st_uid);
+ ce->ce_gid = htonl(st->st_gid);
+ ce->ce_size = htonl(st->st_size);
}
-void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
+static int ce_compare_data(struct cache_entry *ce, struct stat *st)
{
- char *filename = sha1_file_name(sha1);
- int fd = open(filename, O_RDONLY);
- struct stat st;
- void *map;
+ int match = -1;
+ int fd = open(ce->name, O_RDONLY);
- if (fd < 0) {
- perror(filename);
- return NULL;
- }
- if (fstat(fd, &st) < 0) {
+ if (fd >= 0) {
+ unsigned char sha1[20];
+ if (!index_fd(sha1, fd, st, 0, NULL))
+ match = memcmp(sha1, ce->sha1, 20);
close(fd);
- return NULL;
- }
- map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
- close(fd);
- if (-1 == (int)(long)map)
- return NULL;
- *size = st.st_size;
- return map;
-}
-
-void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
-{
- int ret, bytes;
- z_stream stream;
- char buffer[8192];
- char *buf;
-
- /* Get the data stream */
- memset(&stream, 0, sizeof(stream));
- stream.next_in = map;
- stream.avail_in = mapsize;
- stream.next_out = buffer;
- stream.avail_out = sizeof(buffer);
-
- inflateInit(&stream);
- ret = inflate(&stream, 0);
- if (sscanf(buffer, "%10s %lu", type, size) != 2)
- return NULL;
-
- bytes = strlen(buffer) + 1;
- buf = malloc(*size);
- if (!buf)
- return NULL;
-
- memcpy(buf, buffer + bytes, stream.total_out - bytes);
- bytes = stream.total_out - bytes;
- if (bytes < *size && ret == Z_OK) {
- stream.next_out = buf + bytes;
- stream.avail_out = *size - bytes;
- while (inflate(&stream, Z_FINISH) == Z_OK)
- /* nothing */;
}
- inflateEnd(&stream);
- return buf;
+ return match;
}
-void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
+static int ce_compare_link(struct cache_entry *ce, unsigned long expected_size)
{
- unsigned long mapsize;
- void *map, *buf;
-
- map = map_sha1_file(sha1, &mapsize);
- if (map) {
- buf = unpack_sha1_file(map, mapsize, type, size);
- munmap(map, mapsize);
- return buf;
- }
- return NULL;
-}
-
-int write_sha1_file(char *buf, unsigned len, unsigned char *returnsha1)
-{
- int size;
- char *compressed;
- z_stream stream;
- unsigned char sha1[20];
- SHA_CTX c;
-
- /* Set it up */
- memset(&stream, 0, sizeof(stream));
- deflateInit(&stream, Z_BEST_COMPRESSION);
- size = deflateBound(&stream, len);
- compressed = malloc(size);
-
- /* Compress it */
- stream.next_in = buf;
- stream.avail_in = len;
- stream.next_out = compressed;
- stream.avail_out = size;
- while (deflate(&stream, Z_FINISH) == Z_OK)
- /* nothing */;
- deflateEnd(&stream);
- size = stream.total_out;
-
- /* Sha1.. */
- SHA1_Init(&c);
- SHA1_Update(&c, compressed, size);
- SHA1_Final(sha1, &c);
-
- if (write_sha1_buffer(sha1, compressed, size) < 0)
- return -1;
- if (returnsha1)
- memcpy(returnsha1, sha1, 20);
- return 0;
-}
-
-static inline int collision_check(char *filename, void *buf, unsigned int size)
-{
-#ifdef COLLISION_CHECK
- void *map;
- int fd = open(filename, O_RDONLY);
- struct stat st;
- int cmp;
-
- /* Unreadable object, or object went away? Strange. */
- if (fd < 0)
+ int match = -1;
+ char *target;
+ void *buffer;
+ unsigned long size;
+ char type[10];
+ int len;
+
+ target = xmalloc(expected_size);
+ len = readlink(ce->name, target, expected_size);
+ if (len != expected_size) {
+ free(target);
return -1;
-
- if (fstat(fd, &st) < 0 || size != st.st_size)
- return -1;
-
- map = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
- close(fd);
- if (map == MAP_FAILED)
- return -1;
- cmp = memcmp(buf, map, size);
- munmap(map, size);
- if (cmp)
+ }
+ buffer = read_sha1_file(ce->sha1, type, &size);
+ if (!buffer) {
+ free(target);
return -1;
-#endif
- return 0;
+ }
+ if (size == expected_size)
+ match = memcmp(buffer, target, size);
+ free(buffer);
+ free(target);
+ return match;
}
-int write_sha1_buffer(const unsigned char *sha1, void *buf, unsigned int size)
+static int ce_modified_check_fs(struct cache_entry *ce, struct stat *st)
{
- char *filename = sha1_file_name(sha1);
- int fd;
-
- fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
- if (fd < 0) {
- if (errno != EEXIST)
- return -1;
- if (collision_check(filename, buf, size))
- return error("SHA1 collision detected!"
- " This is bad, bad, BAD!\a\n");
- return 0;
+ switch (st->st_mode & S_IFMT) {
+ case S_IFREG:
+ if (ce_compare_data(ce, st))
+ return DATA_CHANGED;
+ break;
+ case S_IFLNK:
+ if (ce_compare_link(ce, st->st_size))
+ return DATA_CHANGED;
+ break;
+ default:
+ return TYPE_CHANGED;
}
- write(fd, buf, size);
- close(fd);
return 0;
}
-int cache_match_stat(struct cache_entry *ce, struct stat *st)
+static int ce_match_stat_basic(struct cache_entry *ce, struct stat *st)
{
unsigned int changed = 0;
+ switch (ntohl(ce->ce_mode) & S_IFMT) {
+ case S_IFREG:
+ changed |= !S_ISREG(st->st_mode) ? TYPE_CHANGED : 0;
+ /* We consider only the owner x bit to be relevant for
+ * "mode changes"
+ */
+ if (trust_executable_bit &&
+ (0100 & (ntohl(ce->ce_mode) ^ st->st_mode)))
+ changed |= MODE_CHANGED;
+ break;
+ case S_IFLNK:
+ changed |= !S_ISLNK(st->st_mode) ? TYPE_CHANGED : 0;
+ break;
+ default:
+ die("internal error: ce_mode is %o", ntohl(ce->ce_mode));
+ }
if (ce->ce_mtime.sec != htonl(st->st_mtime))
changed |= MTIME_CHANGED;
if (ce->ce_ctime.sec != htonl(st->st_ctime))
changed |= CTIME_CHANGED;
-#ifdef NSEC
+#ifdef USE_NSEC
/*
* nsec seems unreliable - not all filesystems support it, so
* as long as it is in the inode cache you get right nsec
* but after it gets flushed, you get zero nsec.
*/
- if (ce->ce_mtime.nsec != htonl(st->st_mtim.tv_nsec)
+ if (ce->ce_mtime.nsec != htonl(st->st_mtim.tv_nsec))
changed |= MTIME_CHANGED;
- if (ce->ce_ctime.nsec != htonl(st->st_ctim.tv_nsec)
+ if (ce->ce_ctime.nsec != htonl(st->st_ctim.tv_nsec))
changed |= CTIME_CHANGED;
#endif
if (ce->ce_uid != htonl(st->st_uid) ||
ce->ce_gid != htonl(st->st_gid))
changed |= OWNER_CHANGED;
- if (ce->ce_mode != htonl(st->st_mode))
- changed |= MODE_CHANGED;
- if (ce->ce_dev != htonl(st->st_dev) ||
- ce->ce_ino != htonl(st->st_ino))
+ if (ce->ce_ino != htonl(st->st_ino))
changed |= INODE_CHANGED;
+
+#ifdef USE_STDEV
+ /*
+ * st_dev breaks on network filesystems where different
+ * clients will have different views of what "device"
+ * the filesystem is on
+ */
+ if (ce->ce_dev != htonl(st->st_dev))
+ changed |= INODE_CHANGED;
+#endif
+
if (ce->ce_size != htonl(st->st_size))
changed |= DATA_CHANGED;
+
return changed;
}
+int ce_match_stat(struct cache_entry *ce, struct stat *st)
+{
+ unsigned int changed = ce_match_stat_basic(ce, st);
+
+ /*
+ * Within 1 second of this sequence:
+ * echo xyzzy >file && git-update-index --add file
+ * running this command:
+ * echo frotz >file
+ * would give a falsely clean cache entry. The mtime and
+ * length match the cache, and other stat fields do not change.
+ *
+ * We could detect this at update-index time (the cache entry
+ * being registered/updated records the same time as "now")
+ * and delay the return from git-update-index, but that would
+ * effectively mean we can make at most one commit per second,
+ * which is not acceptable. Instead, we check cache entries
+ * whose mtime are the same as the index file timestamp more
+ * careful than others.
+ */
+ if (!changed &&
+ index_file_timestamp &&
+ index_file_timestamp <= ntohl(ce->ce_mtime.sec))
+ changed |= ce_modified_check_fs(ce, st);
+
+ return changed;
+}
+
+int ce_modified(struct cache_entry *ce, struct stat *st)
+{
+ int changed, changed_fs;
+ changed = ce_match_stat(ce, st);
+ if (!changed)
+ return 0;
+ /*
+ * If the mode or type has changed, there's no point in trying
+ * to refresh the entry - it's not going to match
+ */
+ if (changed & (MODE_CHANGED | TYPE_CHANGED))
+ return changed;
+
+ /* Immediately after read-tree or update-index --cacheinfo,
+ * the length field is zero. For other cases the ce_size
+ * should match the SHA1 recorded in the index entry.
+ */
+ if ((changed & DATA_CHANGED) && ce->ce_size != htonl(0))
+ return changed;
+
+ changed_fs = ce_modified_check_fs(ce, st);
+ if (changed_fs)
+ return changed | changed_fs;
+ return 0;
+}
+
+int base_name_compare(const char *name1, int len1, int mode1,
+ const char *name2, int len2, int mode2)
+{
+ unsigned char c1, c2;
+ int len = len1 < len2 ? len1 : len2;
+ int cmp;
+
+ cmp = memcmp(name1, name2, len);
+ if (cmp)
+ return cmp;
+ c1 = name1[len];
+ c2 = name2[len];
+ if (!c1 && S_ISDIR(mode1))
+ c1 = '/';
+ if (!c2 && S_ISDIR(mode2))
+ c2 = '/';
+ return (c1 < c2) ? -1 : (c1 > c2) ? 1 : 0;
+}
+
int cache_name_compare(const char *name1, int flags1, const char *name2, int flags2)
{
int len1 = flags1 & CE_NAMEMASK;
while (last > first) {
int next = (last + first) >> 1;
struct cache_entry *ce = active_cache[next];
- int cmp = cache_name_compare(name, namelen, ce->name, htons(ce->ce_flags));
+ int cmp = cache_name_compare(name, namelen, ce->name, ntohs(ce->ce_flags));
if (!cmp)
return next;
if (cmp < 0) {
return -first-1;
}
-int remove_file_from_cache(char *path)
+/* Remove entry, return true if there are more entries to go.. */
+int remove_cache_entry_at(int pos)
+{
+ active_cache_changed = 1;
+ active_nr--;
+ if (pos >= active_nr)
+ return 0;
+ memmove(active_cache + pos, active_cache + pos + 1, (active_nr - pos) * sizeof(struct cache_entry *));
+ return 1;
+}
+
+int remove_file_from_cache(const char *path)
{
int pos = cache_name_pos(path, strlen(path));
- if (pos >= 0) {
- active_nr--;
- if (pos < active_nr)
- memmove(active_cache + pos, active_cache + pos + 1, (active_nr - pos) * sizeof(struct cache_entry *));
+ if (pos < 0)
+ pos = -pos-1;
+ while (pos < active_nr && !strcmp(active_cache[pos]->name, path))
+ remove_cache_entry_at(pos);
+ return 0;
+}
+
+int ce_same_name(struct cache_entry *a, struct cache_entry *b)
+{
+ int len = ce_namelen(a);
+ return ce_namelen(b) == len && !memcmp(a->name, b->name, len);
+}
+
+int ce_path_match(const struct cache_entry *ce, const char **pathspec)
+{
+ const char *match, *name;
+ int len;
+
+ if (!pathspec)
+ return 1;
+
+ len = ce_namelen(ce);
+ name = ce->name;
+ while ((match = *pathspec++) != NULL) {
+ int matchlen = strlen(match);
+ if (matchlen > len)
+ continue;
+ if (memcmp(name, match, matchlen))
+ continue;
+ if (matchlen && name[matchlen-1] == '/')
+ return 1;
+ if (name[matchlen] == '/' || !name[matchlen])
+ return 1;
+ if (!matchlen)
+ return 1;
}
return 0;
}
-int add_cache_entry(struct cache_entry *ce, int ok_to_add)
+/*
+ * Do we have another file that has the beginning components being a
+ * proper superset of the name we're trying to add?
+ */
+static int has_file_name(const struct cache_entry *ce, int pos, int ok_to_replace)
{
- int pos;
+ int retval = 0;
+ int len = ce_namelen(ce);
+ int stage = ce_stage(ce);
+ const char *name = ce->name;
+
+ while (pos < active_nr) {
+ struct cache_entry *p = active_cache[pos++];
+
+ if (len >= ce_namelen(p))
+ break;
+ if (memcmp(name, p->name, len))
+ break;
+ if (ce_stage(p) != stage)
+ continue;
+ if (p->name[len] != '/')
+ continue;
+ retval = -1;
+ if (!ok_to_replace)
+ break;
+ remove_cache_entry_at(--pos);
+ }
+ return retval;
+}
+
+/*
+ * Do we have another file with a pathname that is a proper
+ * subset of the name we're trying to add?
+ */
+static int has_dir_name(const struct cache_entry *ce, int pos, int ok_to_replace)
+{
+ int retval = 0;
+ int stage = ce_stage(ce);
+ const char *name = ce->name;
+ const char *slash = name + ce_namelen(ce);
+
+ for (;;) {
+ int len;
+
+ for (;;) {
+ if (*--slash == '/')
+ break;
+ if (slash <= ce->name)
+ return retval;
+ }
+ len = slash - name;
+
+ pos = cache_name_pos(name, ntohs(create_ce_flags(len, stage)));
+ if (pos >= 0) {
+ retval = -1;
+ if (ok_to_replace)
+ break;
+ remove_cache_entry_at(pos);
+ continue;
+ }
+
+ /*
+ * Trivial optimization: if we find an entry that
+ * already matches the sub-directory, then we know
+ * we're ok, and we can exit.
+ */
+ pos = -pos-1;
+ while (pos < active_nr) {
+ struct cache_entry *p = active_cache[pos];
+ if ((ce_namelen(p) <= len) ||
+ (p->name[len] != '/') ||
+ memcmp(p->name, name, len))
+ break; /* not our subdirectory */
+ if (ce_stage(p) == stage)
+ /* p is at the same stage as our entry, and
+ * is a subdirectory of what we are looking
+ * at, so we cannot have conflicts at our
+ * level or anything shorter.
+ */
+ return retval;
+ pos++;
+ }
+ }
+ return retval;
+}
+
+/* We may be in a situation where we already have path/file and path
+ * is being added, or we already have path and path/file is being
+ * added. Either one would result in a nonsense tree that has path
+ * twice when git-write-tree tries to write it out. Prevent it.
+ *
+ * If ok-to-replace is specified, we remove the conflicting entries
+ * from the cache so the caller should recompute the insert position.
+ * When this happens, we return non-zero.
+ */
+static int check_file_directory_conflict(const struct cache_entry *ce, int pos, int ok_to_replace)
+{
+ /*
+ * We check if the path is a sub-path of a subsequent pathname
+ * first, since removing those will not change the position
+ * in the array
+ */
+ int retval = has_file_name(ce, pos, ok_to_replace);
+ /*
+ * Then check if the path might have a clashing sub-directory
+ * before it.
+ */
+ return retval + has_dir_name(ce, pos, ok_to_replace);
+}
- pos = cache_name_pos(ce->name, htons(ce->ce_flags));
+int add_cache_entry(struct cache_entry *ce, int option)
+{
+ int pos;
+ int ok_to_add = option & ADD_CACHE_OK_TO_ADD;
+ int ok_to_replace = option & ADD_CACHE_OK_TO_REPLACE;
+ int skip_df_check = option & ADD_CACHE_SKIP_DFCHECK;
+ pos = cache_name_pos(ce->name, ntohs(ce->ce_flags));
- /* existing match? Just replace it */
+ /* existing match? Just replace it. */
if (pos >= 0) {
+ active_cache_changed = 1;
active_cache[pos] = ce;
return 0;
}
pos = -pos-1;
+ /*
+ * Inserting a merged entry ("stage 0") into the index
+ * will always replace all non-merged entries..
+ */
+ if (pos < active_nr && ce_stage(ce) == 0) {
+ while (ce_same_name(active_cache[pos], ce)) {
+ ok_to_add = 1;
+ if (!remove_cache_entry_at(pos))
+ break;
+ }
+ }
+
if (!ok_to_add)
return -1;
+ if (!skip_df_check &&
+ check_file_directory_conflict(ce, pos, ok_to_replace)) {
+ if (!ok_to_replace)
+ return -1;
+ pos = cache_name_pos(ce->name, ntohs(ce->ce_flags));
+ pos = -pos-1;
+ }
+
/* Make sure the array is big enough .. */
if (active_nr == active_alloc) {
active_alloc = alloc_nr(active_alloc);
- active_cache = realloc(active_cache, active_alloc * sizeof(struct cache_entry *));
+ active_cache = xrealloc(active_cache, active_alloc * sizeof(struct cache_entry *));
}
/* Add it in.. */
if (active_nr > pos)
memmove(active_cache + pos + 1, active_cache + pos, (active_nr - pos - 1) * sizeof(ce));
active_cache[pos] = ce;
+ active_cache_changed = 1;
return 0;
}
if (hdr->hdr_signature != htonl(CACHE_SIGNATURE))
return error("bad signature");
- if (hdr->hdr_version != htonl(1))
- return error("bad version");
+ if (hdr->hdr_version != htonl(2))
+ return error("bad index version");
SHA1_Init(&c);
- SHA1_Update(&c, hdr, offsetof(struct cache_header, sha1));
- SHA1_Update(&c, hdr+1, size - sizeof(*hdr));
+ SHA1_Update(&c, hdr, size - 20);
SHA1_Final(sha1, &c);
- if (memcmp(sha1, hdr->sha1, 20))
- return error("bad header sha1");
+ if (memcmp(sha1, (void *)hdr + size - 20, 20))
+ return error("bad index file sha1 signature");
return 0;
}
errno = EBUSY;
if (active_cache)
- return error("more than one cachefile");
+ return active_nr;
+
errno = ENOENT;
- sha1_file_directory = getenv(DB_ENVIRONMENT);
- if (!sha1_file_directory)
- sha1_file_directory = DEFAULT_DB_ENVIRONMENT;
- if (access(sha1_file_directory, X_OK) < 0)
- return error("no access to SHA1 file directory");
- fd = open(".git/index", O_RDONLY);
- if (fd < 0)
- return (errno == ENOENT) ? 0 : error("open failed");
+ index_file_timestamp = 0;
+ fd = open(get_index_file(), O_RDONLY);
+ if (fd < 0) {
+ if (errno == ENOENT)
+ return 0;
+ die("index file open failed (%s)", strerror(errno));
+ }
size = 0; // avoid gcc warning
- map = (void *)-1;
+ map = MAP_FAILED;
if (!fstat(fd, &st)) {
size = st.st_size;
errno = EINVAL;
- if (size >= sizeof(struct cache_header))
- map = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
+ if (size >= sizeof(struct cache_header) + 20)
+ map = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
}
close(fd);
- if (-1 == (int)(long)map)
- return error("mmap failed");
+ if (map == MAP_FAILED)
+ die("index file mmap failed (%s)", strerror(errno));
hdr = map;
if (verify_hdr(hdr, size) < 0)
offset = offset + ce_size(ce);
active_cache[i] = ce;
}
+ index_file_timestamp = st.st_mtime;
return active_nr;
unmap:
munmap(map, size);
errno = EINVAL;
- return error("verify header failed");
+ die("index file corrupt");
+}
+
+#define WRITE_BUFFER_SIZE 8192
+static unsigned char write_buffer[WRITE_BUFFER_SIZE];
+static unsigned long write_buffer_len;
+
+static int ce_write(SHA_CTX *context, int fd, void *data, unsigned int len)
+{
+ while (len) {
+ unsigned int buffered = write_buffer_len;
+ unsigned int partial = WRITE_BUFFER_SIZE - buffered;
+ if (partial > len)
+ partial = len;
+ memcpy(write_buffer + buffered, data, partial);
+ buffered += partial;
+ if (buffered == WRITE_BUFFER_SIZE) {
+ SHA1_Update(context, write_buffer, WRITE_BUFFER_SIZE);
+ if (write(fd, write_buffer, WRITE_BUFFER_SIZE) != WRITE_BUFFER_SIZE)
+ return -1;
+ buffered = 0;
+ }
+ write_buffer_len = buffered;
+ len -= partial;
+ data += partial;
+ }
+ return 0;
+}
+
+static int ce_flush(SHA_CTX *context, int fd)
+{
+ unsigned int left = write_buffer_len;
+
+ if (left) {
+ write_buffer_len = 0;
+ SHA1_Update(context, write_buffer, left);
+ }
+
+ /* Flush first if not enough space for SHA1 signature */
+ if (left + 20 > WRITE_BUFFER_SIZE) {
+ if (write(fd, write_buffer, left) != left)
+ return -1;
+ left = 0;
+ }
+
+ /* Append the SHA1 signature at the end */
+ SHA1_Final(write_buffer + left, context);
+ left += 20;
+ if (write(fd, write_buffer, left) != left)
+ return -1;
+ return 0;
+}
+
+static void ce_smudge_racily_clean_entry(struct cache_entry *ce)
+{
+ /*
+ * The only thing we care about in this function is to smudge the
+ * falsely clean entry due to touch-update-touch race, so we leave
+ * everything else as they are. We are called for entries whose
+ * ce_mtime match the index file mtime.
+ */
+ struct stat st;
+
+ if (lstat(ce->name, &st) < 0)
+ return;
+ if (ce_match_stat_basic(ce, &st))
+ return;
+ if (ce_modified_check_fs(ce, &st)) {
+ /* This is "racily clean"; smudge it. Note that this
+ * is a tricky code. At first glance, it may appear
+ * that it can break with this sequence:
+ *
+ * $ echo xyzzy >frotz
+ * $ git-update-index --add frotz
+ * $ : >frotz
+ * $ sleep 3
+ * $ echo filfre >nitfol
+ * $ git-update-index --add nitfol
+ *
+ * but it does not. Whe the second update-index runs,
+ * it notices that the entry "frotz" has the same timestamp
+ * as index, and if we were to smudge it by resetting its
+ * size to zero here, then the object name recorded
+ * in index is the 6-byte file but the cached stat information
+ * becomes zero --- which would then match what we would
+ * obtain from the filesystem next time we stat("frotz").
+ *
+ * However, the second update-index, before calling
+ * this function, notices that the cached size is 6
+ * bytes and what is on the filesystem is an empty
+ * file, and never calls us, so the cached size information
+ * for "frotz" stays 6 which does not match the filesystem.
+ */
+ ce->ce_size = htonl(0);
+ }
}
int write_cache(int newfd, struct cache_entry **cache, int entries)
{
SHA_CTX c;
struct cache_header hdr;
- int i;
+ int i, removed;
+
+ for (i = removed = 0; i < entries; i++)
+ if (!cache[i]->ce_mode)
+ removed++;
hdr.hdr_signature = htonl(CACHE_SIGNATURE);
- hdr.hdr_version = htonl(1);
- hdr.hdr_entries = htonl(entries);
+ hdr.hdr_version = htonl(2);
+ hdr.hdr_entries = htonl(entries - removed);
SHA1_Init(&c);
- SHA1_Update(&c, &hdr, offsetof(struct cache_header, sha1));
- for (i = 0; i < entries; i++) {
- struct cache_entry *ce = cache[i];
- int size = ce_size(ce);
- SHA1_Update(&c, ce, size);
- }
- SHA1_Final(hdr.sha1, &c);
-
- if (write(newfd, &hdr, sizeof(hdr)) != sizeof(hdr))
+ if (ce_write(&c, newfd, &hdr, sizeof(hdr)) < 0)
return -1;
for (i = 0; i < entries; i++) {
struct cache_entry *ce = cache[i];
- int size = ce_size(ce);
- if (write(newfd, ce, size) != size)
+ if (!ce->ce_mode)
+ continue;
+ if (index_file_timestamp &&
+ index_file_timestamp <= ntohl(ce->ce_mtime.sec))
+ ce_smudge_racily_clean_entry(ce);
+ if (ce_write(&c, newfd, ce, ce_size(ce)) < 0)
return -1;
}
- return 0;
+ return ce_flush(&c, newfd);
}