summaryrefslogtreecommitdiff
path: root/read-cache.c
diff options
context:
space:
mode:
Diffstat (limited to 'read-cache.c')
-rw-r--r--read-cache.c499
1 files changed, 499 insertions, 0 deletions
diff --git a/read-cache.c b/read-cache.c
new file mode 100644
index 0000000000..ced597318e
--- /dev/null
+++ b/read-cache.c
@@ -0,0 +1,499 @@
+/*
+ * GIT - The information manager from hell
+ *
+ * Copyright (C) Linus Torvalds, 2005
+ */
+#include "cache.h"
+
+struct cache_entry **active_cache = NULL;
+unsigned int active_nr = 0, active_alloc = 0, active_cache_changed = 0;
+
+/*
+ * 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.
+ */
+void fill_stat_cache_info(struct cache_entry *ce, struct stat *st)
+{
+ 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);
+}
+
+int ce_match_stat(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 (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 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))
+ changed |= MTIME_CHANGED;
+ 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_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 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;
+ int len2 = flags2 & CE_NAMEMASK;
+ int len = len1 < len2 ? len1 : len2;
+ int cmp;
+
+ cmp = memcmp(name1, name2, len);
+ if (cmp)
+ return cmp;
+ if (len1 < len2)
+ return -1;
+ if (len1 > len2)
+ return 1;
+ if (flags1 < flags2)
+ return -1;
+ if (flags1 > flags2)
+ return 1;
+ return 0;
+}
+
+int cache_name_pos(const char *name, int namelen)
+{
+ int first, last;
+
+ first = 0;
+ last = active_nr;
+ while (last > first) {
+ int next = (last + first) >> 1;
+ struct cache_entry *ce = active_cache[next];
+ int cmp = cache_name_compare(name, namelen, ce->name, ntohs(ce->ce_flags));
+ if (!cmp)
+ return next;
+ if (cmp < 0) {
+ last = next;
+ continue;
+ }
+ first = next+1;
+ }
+ return -first-1;
+}
+
+/* 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(char *path)
+{
+ int pos = cache_name_pos(path, strlen(path));
+ 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;
+}
+
+/*
+ * 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 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);
+}
+
+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 */
+ 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 = xrealloc(active_cache, active_alloc * sizeof(struct cache_entry *));
+ }
+
+ /* Add it in.. */
+ active_nr++;
+ 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;
+}
+
+static int verify_hdr(struct cache_header *hdr, unsigned long size)
+{
+ SHA_CTX c;
+ unsigned char sha1[20];
+
+ if (hdr->hdr_signature != htonl(CACHE_SIGNATURE))
+ return error("bad signature");
+ if (hdr->hdr_version != htonl(2))
+ return error("bad index version");
+ SHA1_Init(&c);
+ SHA1_Update(&c, hdr, size - 20);
+ SHA1_Final(sha1, &c);
+ if (memcmp(sha1, (void *)hdr + size - 20, 20))
+ return error("bad index file sha1 signature");
+ return 0;
+}
+
+int read_cache(void)
+{
+ int fd, i;
+ struct stat st;
+ unsigned long size, offset;
+ void *map;
+ struct cache_header *hdr;
+
+ errno = EBUSY;
+ if (active_cache)
+ return error("more than one cachefile");
+ errno = ENOENT;
+ fd = open(get_index_file(), O_RDONLY);
+ if (fd < 0)
+ return (errno == ENOENT) ? 0 : error("open failed");
+
+ size = 0; // avoid gcc warning
+ map = MAP_FAILED;
+ if (!fstat(fd, &st)) {
+ size = st.st_size;
+ errno = EINVAL;
+ if (size >= sizeof(struct cache_header) + 20)
+ map = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
+ }
+ close(fd);
+ if (map == MAP_FAILED)
+ return error("mmap failed");
+
+ hdr = map;
+ if (verify_hdr(hdr, size) < 0)
+ goto unmap;
+
+ active_nr = ntohl(hdr->hdr_entries);
+ active_alloc = alloc_nr(active_nr);
+ active_cache = calloc(active_alloc, sizeof(struct cache_entry *));
+
+ offset = sizeof(*hdr);
+ for (i = 0; i < active_nr; i++) {
+ struct cache_entry *ce = map + offset;
+ offset = offset + ce_size(ce);
+ active_cache[i] = ce;
+ }
+ return active_nr;
+
+unmap:
+ munmap(map, size);
+ errno = EINVAL;
+ return error("verify header failed");
+}
+
+#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);
+ }
+
+ /* 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;
+}
+
+int write_cache(int newfd, struct cache_entry **cache, int entries)
+{
+ SHA_CTX c;
+ struct cache_header hdr;
+ 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(2);
+ hdr.hdr_entries = htonl(entries - removed);
+
+ SHA1_Init(&c);
+ if (ce_write(&c, newfd, &hdr, sizeof(hdr)) < 0)
+ return -1;
+
+ for (i = 0; i < entries; i++) {
+ struct cache_entry *ce = cache[i];
+ if (!ce->ce_mode)
+ continue;
+ if (ce_write(&c, newfd, ce, ce_size(ce)) < 0)
+ return -1;
+ }
+ return ce_flush(&c, newfd);
+}
generated by cgit v1.2.3 (git 2.25.1) at 2025-01-26 21:51:43 +0000