Make "update-cache --refresh" do what it really should do: just
refresh the "stat" information.
We need this after having done a "read-tree", for example, when the
stat information does not match the checked-out tree, and we want to
start getting efficient cache matching against the parts of the tree
that are already up-to-date.
diff --git a/update-cache.c b/update-cache.c
index 942e309..68a0ae0 100644
--- a/update-cache.c
+++ b/update-cache.c
@@ -57,6 +57,23 @@
return write_sha1_buffer(ce->sha1, out, stream.total_out);
}
+/*
+ * 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.
+ */
+static void fill_stat_cache_info(struct cache_entry *ce, struct stat *st)
+{
+ ce->ctime.sec = st->st_ctime;
+ ce->ctime.nsec = st->st_ctim.tv_nsec;
+ ce->mtime.sec = st->st_mtime;
+ ce->mtime.nsec = st->st_mtim.tv_nsec;
+ ce->st_dev = st->st_dev;
+ ce->st_ino = st->st_ino;
+ ce->st_uid = st->st_uid;
+ ce->st_gid = st->st_gid;
+}
+
static int add_file_to_cache(char *path)
{
int size, namelen;
@@ -81,15 +98,8 @@
ce = malloc(size);
memset(ce, 0, size);
memcpy(ce->name, path, namelen);
- ce->ctime.sec = st.st_ctime;
- ce->ctime.nsec = st.st_ctim.tv_nsec;
- ce->mtime.sec = st.st_mtime;
- ce->mtime.nsec = st.st_mtim.tv_nsec;
- ce->st_dev = st.st_dev;
- ce->st_ino = st.st_ino;
+ fill_stat_cache_info(ce, &st);
ce->st_mode = st.st_mode;
- ce->st_uid = st.st_uid;
- ce->st_gid = st.st_gid;
ce->st_size = st.st_size;
ce->namelen = namelen;
@@ -99,26 +109,96 @@
return add_cache_entry(ce, allow_add);
}
-static void refresh_entry(struct cache_entry *ce)
+static int match_data(int fd, void *buffer, unsigned long size)
{
+ while (size) {
+ char compare[1024];
+ int ret = read(fd, compare, sizeof(compare));
+
+ if (ret <= 0 || ret > size || memcmp(buffer, compare, ret))
+ return -1;
+ size -= ret;
+ buffer += ret;
+ }
+ return 0;
+}
+
+static int compare_data(struct cache_entry *ce)
+{
+ int match = -1;
+ int fd = open(ce->name, O_RDONLY);
+
+ if (fd >= 0) {
+ void *buffer;
+ unsigned long size;
+ char type[10];
+
+ buffer = read_sha1_file(ce->sha1, type, &size);
+ if (buffer) {
+ if (size == ce->st_size && !strcmp(type, "blob"))
+ match = match_data(fd, buffer, size);
+ free(buffer);
+ }
+ close(fd);
+ }
+ return match;
+}
+
+/*
+ * "refresh" does not calculate a new sha1 file or bring the
+ * cache up-to-date for mode/content changes. But what it
+ * _does_ do is to "re-match" the stat information of a file
+ * with the cache, so that you can refresh the cache for a
+ * file that hasn't been changed but where the stat entry is
+ * out of date.
+ *
+ * For example, you'd want to do this after doing a "read-tree",
+ * to link up the stat cache details with the proper files.
+ */
+static struct cache_entry *refresh_entry(struct cache_entry *ce)
+{
+ struct stat st;
+ struct cache_entry *updated;
+ int changed, size;
+
+ if (stat(ce->name, &st) < 0)
+ return NULL;
+
+ changed = cache_match_stat(ce, &st);
+ if (!changed)
+ return ce;
+
/*
- * This is really not the right way to do it, but
- * add_file_to_cache() does do the right thing.
- *
- * We should really just update the cache
- * entry in-place, I think. With this approach we
- * end up allocating a new one, searching for where
- * to insert it etc etc crud.
+ * If the length has changed, there's no point in trying
+ * to refresh the entry - it's not going to match
*/
- add_file_to_cache(ce->name);
+ if (changed & (DATA_CHANGED | MODE_CHANGED))
+ return NULL;
+
+ if (compare_data(ce))
+ return NULL;
+
+ size = ce_size(ce);
+ updated = malloc(size);
+ memcpy(updated, ce, size);
+ fill_stat_cache_info(updated, &st);
+ return updated;
}
static void refresh_cache(void)
{
int i;
- for (i = 0; i < active_nr; i++)
- refresh_entry(active_cache[i]);
+ for (i = 0; i < active_nr; i++) {
+ struct cache_entry *ce = active_cache[i];
+ struct cache_entry *new = refresh_entry(ce);
+
+ if (!new) {
+ printf("%s: needs update\n", ce->name);
+ continue;
+ }
+ active_cache[i] = new;
+ }
}
/*
