[PATCH] Use SHA1 for git-update-cache --refresh

Change git-update-cache --refresh behaviour to use sha1's rather than
comparing byte by byte.

[JC demangled whitespace from the posted patch himself because he
 liked it so much.  Also adjusted to the index_fd() interface
 slightly done differently from the original one.]

Signed-off-by: Bryan Larsen <bryan.larsen@gmail.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/update-cache.c b/update-cache.c
index cc4298a..1fcc59a 100644 (file)
--- a/update-cache.c
+++ b/update-cache.c
@@ -94,36 +94,15 @@ static int add_file_to_cache(char *path)
        return add_cache_entry(ce, option);
 }
 
-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, unsigned long expected_size)
+static int compare_data(struct cache_entry *ce, struct stat *st)
 {
        int match = -1;
        int fd = open(ce->name, O_RDONLY);
 
        if (fd >= 0) {
-               void *buffer;
-               unsigned long size;
-               char type[20];
-
-               buffer = read_sha1_file(ce->sha1, type, &size);
-               if (buffer) {
-                       if (size == expected_size && !strcmp(type, "blob"))
-                               match = match_data(fd, buffer, size);
-                       free(buffer);
-               }
+               unsigned char sha1[20];
+               if (!index_fd(sha1, fd, st, 0, NULL))
+                       match = memcmp(sha1, ce->sha1, 20);
                close(fd);
        }
        return match;
@@ -189,7 +168,7 @@ static struct cache_entry *refresh_entry(struct cache_entry *ce)
 
        switch (st.st_mode & S_IFMT) {
        case S_IFREG:
-               if (compare_data(ce, st.st_size))
+               if (compare_data(ce, &st))
                        return ERR_PTR(-EINVAL);
                break;
        case S_IFLNK: