write_entry(): use fstat() instead of lstat() when file is open

Currently inside write_entry() we do an lstat(path, &st) call on a
file which have just been opened inside the exact same function.  It
should be better to call fstat(fd, &st) on the file while it is open,
and it should be at least as fast as the lstat() method.

Signed-off-by: Kjetil Barvik <barvik@broadpark.no>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/entry.c b/entry.c
index 1f53588a11aee0debef472b6cce09c8798a3e3af..5daacc2fe51eada819bedea05f958fbf87f5b889 100644 (file)
--- a/entry.c
+++ b/entry.c
@@ -94,11 +94,12 @@ static void *read_blob_entry(struct cache_entry *ce, unsigned long *size)
 static int write_entry(struct cache_entry *ce, char *path, const struct checkout *state, int to_tempfile)
 {
        unsigned int ce_mode_s_ifmt = ce->ce_mode & S_IFMT;
-       int fd, ret;
+       int fd, ret, fstat_done = 0;
        char *new;
        struct strbuf buf = STRBUF_INIT;
        unsigned long size;
        size_t wrote, newsize = 0;
+       struct stat st;
 
        switch (ce_mode_s_ifmt) {
        case S_IFREG:
@@ -145,6 +146,11 @@ static int write_entry(struct cache_entry *ce, char *path, const struct checkout
                }
 
                wrote = write_in_full(fd, new, size);
+               /* use fstat() only when path == ce->name */
+               if (state->refresh_cache && !to_tempfile && !state->base_dir_len) {
+                       fstat(fd, &st);
+                       fstat_done = 1;
+               }
                close(fd);
                free(new);
                if (wrote != size)
@@ -161,8 +167,8 @@ static int write_entry(struct cache_entry *ce, char *path, const struct checkout
        }
 
        if (state->refresh_cache) {
-               struct stat st;
-               lstat(ce->name, &st);
+               if (!fstat_done)
+                       lstat(ce->name, &st);
                fill_stat_cache_info(ce, &st);
        }
        return 0;