1 files changed, 68 insertions, 0 deletions
diff --git a/worktree.c b/worktree.c
index 821b233479..8ae019af79 100644
--- a/worktree.c
+++ b/worktree.c
@@ -741,3 +741,71 @@ done:
 	strbuf_release(&realdotgit);
 	strbuf_release(&dotgit);
 }
+
+int should_prune_worktree(const char *id, struct strbuf *reason, char **wtpath, timestamp_t expire)
+{
+	struct stat st;
+	char *path;
+	int fd;
+	size_t len;
+	ssize_t read_result;
+
+	*wtpath = NULL;
+	if (!is_directory(git_path("worktrees/%s", id))) {
+		strbuf_addstr(reason, _("not a valid directory"));
+		return 1;
+	}
+	if (file_exists(git_path("worktrees/%s/locked", id)))
+		return 0;
+	if (stat(git_path("worktrees/%s/gitdir", id), &st)) {
+		strbuf_addstr(reason, _("gitdir file does not exist"));
+		return 1;
+	}
+	fd = open(git_path("worktrees/%s/gitdir", id), O_RDONLY);
+	if (fd < 0) {
+		strbuf_addf(reason, _("unable to read gitdir file (%s)"),
+			    strerror(errno));
+		return 1;
+	}
+	len = xsize_t(st.st_size);
+	path = xmallocz(len);
+
+	read_result = read_in_full(fd, path, len);
+	if (read_result < 0) {
+		strbuf_addf(reason, _("unable to read gitdir file (%s)"),
+			    strerror(errno));
+		close(fd);
+		free(path);
+		return 1;
+	}
+	close(fd);
+
+	if (read_result != len) {
+		strbuf_addf(reason,
+			    _("short read (expected %"PRIuMAX" bytes, read %"PRIuMAX")"),
+			    (uintmax_t)len, (uintmax_t)read_result);
+		free(path);
+		return 1;
+	}
+	while (len && (path[len - 1] == '\n' || path[len - 1] == '\r'))
+		len--;
+	if (!len) {
+		strbuf_addstr(reason, _("invalid gitdir file"));
+		free(path);
+		return 1;
+	}
+	path[len] = '\0';
+	if (!file_exists(path)) {
+		if (stat(git_path("worktrees/%s/index", id), &st) ||
+		    st.st_mtime <= expire) {
+			strbuf_addstr(reason, _("gitdir file points to non-existent location"));
+			free(path);
+			return 1;
+		} else {
+			*wtpath = path;
+			return 0;
+		}
+	}
+	*wtpath = path;
+	return 0;
+}