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[git.git] / read-cache.c

diff --git a/read-cache.c b/read-cache.c
index 6eff4c8..ef6fd79 100644 (file)
--- a/read-cache.c
+++ b/read-cache.c
@@ -83,6 +83,83 @@ int ce_match_stat(struct cache_entry *ce, struct stat *st)
        return changed;
 }
 
+static int ce_compare_data(struct cache_entry *ce, struct stat *st)
+{
+       int match = -1;
+       int fd = open(ce->name, O_RDONLY);
+
+       if (fd >= 0) {
+               unsigned char sha1[20];
+               if (!index_fd(sha1, fd, st, 0, NULL))
+                       match = memcmp(sha1, ce->sha1, 20);
+               close(fd);
+       }
+       return match;
+}
+
+static int ce_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;
+}
+
+int ce_modified(struct cache_entry *ce, struct stat *st)
+{
+       int changed;
+       changed = ce_match_stat(ce, st);
+       if (!changed)
+               return 0;
+
+       /*
+        * 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 | TYPE_CHANGED))
+               return changed;
+
+       /* Immediately after read-tree or update-index --cacheinfo,
+        * the length field is zero.  For other cases the ce_size
+        * should match the SHA1 recorded in the index entry.
+        */
+       if ((changed & DATA_CHANGED) && ce->ce_size != htonl(0))
+               return changed;
+
+       switch (st->st_mode & S_IFMT) {
+       case S_IFREG:
+               if (ce_compare_data(ce, st))
+                       return changed | DATA_CHANGED;
+               break;
+       case S_IFLNK:
+               if (ce_compare_link(ce, st->st_size))
+                       return changed | DATA_CHANGED;
+               break;
+       default:
+               return changed | TYPE_CHANGED;
+       }
+       return 0;
+}
+
 int base_name_compare(const char *name1, int len1, int mode1,
                      const char *name2, int len2, int mode2)
 {