+ /* Make sure it is a "refs/.." symlink */
+ if (S_ISLNK(st.st_mode)) {
+ len = readlink(path, buffer, sizeof(buffer)-1);
+ if (len >= 5 && !memcmp("refs/", buffer, 5))
+ return 0;
+ return -1;
+ }
+
+ /*
+ * Anything else, just open it and try to see if it is a symbolic ref.
+ */
+ fd = open(path, O_RDONLY);
+ if (fd < 0)
+ return -1;
+ len = read(fd, buffer, sizeof(buffer)-1);
+ close(fd);
+
+ /*
+ * Is it a symbolic ref?
+ */
+ if (len < 4 || memcmp("ref:", buffer, 4))
+ return -1;
+ buf = buffer + 4;
+ len -= 4;
+ while (len && isspace(*buf))
+ buf++, len--;
+ if (len >= 5 && !memcmp("refs/", buf, 5))
+ return 0;
+ return -1;
+}
+
+const char *resolve_ref(const char *path, unsigned char *sha1, int reading)
+{
+ int depth = MAXDEPTH, len;
+ char buffer[256];
+
+ for (;;) {
+ struct stat st;
+ char *buf;
+ int fd;
+
+ if (--depth < 0)
+ return NULL;
+
+ /* Special case: non-existing file.
+ * Not having the refs/heads/new-branch is OK
+ * if we are writing into it, so is .git/HEAD
+ * that points at refs/heads/master still to be
+ * born. It is NOT OK if we are resolving for
+ * reading.
+ */
+ if (lstat(path, &st) < 0) {
+ if (reading || errno != ENOENT)
+ return NULL;
+ memset(sha1, 0, 20);
+ return path;
+ }
+
+ /* Follow "normalized" - ie "refs/.." symlinks by hand */
+ if (S_ISLNK(st.st_mode)) {
+ len = readlink(path, buffer, sizeof(buffer)-1);
+ if (len >= 5 && !memcmp("refs/", buffer, 5)) {
+ path = git_path("%.*s", len, buffer);
+ continue;
+ }
+ }
+
+ /*
+ * Anything else, just open it and try to use it as
+ * a ref
+ */
+ fd = open(path, O_RDONLY);
+ if (fd < 0)
+ return NULL;
+ len = read(fd, buffer, sizeof(buffer)-1);