X-Git-Url: https://git.verplant.org/?a=blobdiff_plain;f=update-cache.c;h=97d5e8b6b0695b82a235026430050a4140a1586a;hb=a02ebff6127c5fc981668fb570f0a80f2b7657ca;hp=bb25fa114c1017380c8441f514ae2e66beef1e68;hpb=0ff5bf7cfcb20a6c2404fe7b9cc6ff18e47db812;p=git.git

diff --git a/update-cache.c b/update-cache.c
index bb25fa11..97d5e8b6 100644
--- a/update-cache.c
+++ b/update-cache.c
@@ -15,6 +15,12 @@
  */
 static int allow_add = 0, allow_remove = 0, not_new = 0;
 
+/*
+ * update-cache --refresh may not touch anything at all, in which case
+ * writing 1.6MB of the same thing is a waste.
+ */
+static int cache_changed = 0;
+
 /* Three functions to allow overloaded pointer return; see linux/err.h */
 static inline void *ERR_PTR(long error)
 {
@@ -51,25 +57,21 @@ static void fill_stat_cache_info(struct cache_entry *ce, struct stat *st)
 	ce->ce_size = htonl(st->st_size);
 }
 
-static int add_file_to_cache(char *path)
+static int add_file_to_cache_1(char *path)
 {
 	int size, namelen;
 	struct cache_entry *ce;
 	struct stat st;
 	int fd;
+	char *target;
 
-	fd = open(path, O_RDONLY);
-	if (fd < 0) {
+	if (lstat(path, &st) < 0) {
 		if (errno == ENOENT || errno == ENOTDIR) {
 			if (allow_remove)
 				return remove_file_from_cache(path);
 		}
 		return -1;
 	}
-	if (fstat(fd, &st) < 0) {
-		close(fd);
-		return -1;
-	}
 	namelen = strlen(path);
 	size = cache_entry_size(namelen);
 	ce = xmalloc(size);
@@ -78,13 +80,56 @@ static int add_file_to_cache(char *path)
 	fill_stat_cache_info(ce, &st);
 	ce->ce_mode = create_ce_mode(st.st_mode);
 	ce->ce_flags = htons(namelen);
-
-	if (index_fd(ce->sha1, fd, &st) < 0)
+	switch (st.st_mode & S_IFMT) {
+	case S_IFREG:
+		fd = open(path, O_RDONLY);
+		if (fd < 0)
+			return -1;
+		if (index_fd(ce->sha1, fd, &st) < 0)
+			return -1;
+		break;
+	case S_IFLNK:
+		target = xmalloc(st.st_size+1);
+		if (readlink(path, target, st.st_size+1) != st.st_size) {
+			free(target);
+			return -1;
+		}
+		if (write_sha1_file(target, st.st_size, "blob", ce->sha1))
+			return -1;
+		free(target);
+		break;
+	default:
 		return -1;
-
+	}
+	if (!cache_changed) {
+		/* If we have not smudged the cache, be careful
+		 * to keep it clean.  Find out if we have a matching
+		 * cache entry that add_cache_entry would replace with,
+		 * and if it matches then do not bother calling it.
+		 */
+		int pos = cache_name_pos(ce->name, namelen);
+		if ((0 <= pos) &&
+		    !memcmp(active_cache[pos], ce, sizeof(*ce))) {
+			free(ce);
+			/* magic to tell add_file_to_cache that
+			 * we have not updated anything.
+			 */
+			return 999;
+		}
+	}
 	return add_cache_entry(ce, allow_add);
 }
 
+static int add_file_to_cache(char *path)
+{
+	int ret = add_file_to_cache_1(path);
+	if (ret == 0)
+		cache_changed = 1;
+	else if (ret == 999)
+		ret = 0;
+	return ret;
+}
+
 static int match_data(int fd, void *buffer, unsigned long size)
 {
 	while (size) {
@@ -120,6 +165,33 @@ static int compare_data(struct cache_entry *ce, unsigned long expected_size)
 	return match;
 }
 
+static int compare_link(struct cache_entry *ce, unsigned long expected_size)
+{
+	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;
+	}
+	buffer = read_sha1_file(ce->sha1, type, &size);
+	if (!buffer) {
+		free(target);
+		return -1;
+	}
+	if (size == expected_size)
+		match = memcmp(buffer, target, size);
+	free(buffer);
+	free(target);
+	return match;
+}
+
 /*
  * "refresh" does not calculate a new sha1 file or bring the
  * cache up-to-date for mode/content changes. But what it
@@ -137,7 +209,7 @@ static struct cache_entry *refresh_entry(struct cache_entry *ce)
 	struct cache_entry *updated;
 	int changed, size;
 
-	if (stat(ce->name, &st) < 0)
+	if (lstat(ce->name, &st) < 0)
 		return ERR_PTR(-errno);
 
 	changed = cache_match_stat(ce, &st);
@@ -145,15 +217,26 @@ static struct cache_entry *refresh_entry(struct cache_entry *ce)
 		return ce;
 
 	/*
-	 * If the mode has changed, there's no point in trying
+	 * 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)
+	if (changed & (MODE_CHANGED | TYPE_CHANGED))
 		return ERR_PTR(-EINVAL);
 
-	if (compare_data(ce, st.st_size))
+	switch (st.st_mode & S_IFMT) {
+	case S_IFREG:
+		if (compare_data(ce, st.st_size))
+			return ERR_PTR(-EINVAL);
+		break;
+	case S_IFLNK:
+		if (compare_link(ce, st.st_size))
+			return ERR_PTR(-EINVAL);
+		break;
+	default:
 		return ERR_PTR(-EINVAL);
+	}
 
+	cache_changed = 1;
 	size = ce_size(ce);
 	updated = xmalloc(size);
 	memcpy(updated, ce, size);
@@ -234,6 +317,7 @@ static int add_cacheinfo(char *arg1, char *arg2, char *arg3)
 	if (!verify_path(arg3))
 		return -1;
 
+	cache_changed = 1;
 	len = strlen(arg3);
 	size = cache_entry_size(len);
 	ce = xmalloc(size);
@@ -328,9 +412,13 @@ int main(int argc, char **argv)
 		if (add_file_to_cache(path))
 			die("Unable to add %s to database", path);
 	}
-	if (write_cache(newfd, active_cache, active_nr) || rename(lockfile, indexfile))
+
+	if (!cache_changed)
+		unlink(lockfile);
+	else if (write_cache(newfd, active_cache, active_nr) ||
+		 rename(lockfile, indexfile))
 		die("Unable to write new cachefile");
 
 	lockfile_name = NULL;
-	return has_errors;
+	return has_errors ? 1 : 0;
 }