1 files changed, 39 insertions, 19 deletions

diff --git a/commit-graph.c b/commit-graph.c
index 5e8a3a5085..12cdd9af8e 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -513,31 +513,34 @@ static int add_graph_to_chain(struct commit_graph *g,
 	return 1;
 }
 
-static struct commit_graph *load_commit_graph_chain(struct repository *r,
-						    struct object_directory *odb)
+int open_commit_graph_chain(const char *chain_file,
+			    int *fd, struct stat *st)
+{
+	*fd = git_open(chain_file);
+	if (*fd < 0)
+		return 0;
+	if (fstat(*fd, st)) {
+		close(*fd);
+		return 0;
+	}
+	if (st->st_size <= the_hash_algo->hexsz) {
+		close(*fd);
+		errno = ENOENT;
+		return 0;
+	}
+	return 1;
+}
+
+struct commit_graph *load_commit_graph_chain_fd_st(struct repository *r,
+						   int fd, struct stat *st)
 {
 	struct commit_graph *graph_chain = NULL;
 	struct strbuf line = STRBUF_INIT;
-	struct stat st;
 	struct object_id *oids;
 	int i = 0, valid = 1, count;
-	char *chain_name = get_commit_graph_chain_filename(odb);
-	FILE *fp;
-	int stat_res;
+	FILE *fp = xfdopen(fd, "r");
 
-	fp = fopen(chain_name, "r");
-	stat_res = stat(chain_name, &st);
-	free(chain_name);
-
-	if (!fp)
-		return NULL;
-	if (stat_res ||
-	    st.st_size <= the_hash_algo->hexsz) {
-		fclose(fp);
-		return NULL;
-	}
-
-	count = st.st_size / (the_hash_algo->hexsz + 1);
+	count = st->st_size / (the_hash_algo->hexsz + 1);
 	CALLOC_ARRAY(oids, count);
 
 	prepare_alt_odb(r);
@@ -585,6 +588,23 @@ static struct commit_graph *load_commit_graph_chain(struct repository *r,
 	return graph_chain;
 }
 
+static struct commit_graph *load_commit_graph_chain(struct repository *r,
+						    struct object_directory *odb)
+{
+	char *chain_file = get_commit_graph_chain_filename(odb);
+	struct stat st;
+	int fd;
+	struct commit_graph *g = NULL;
+
+	if (open_commit_graph_chain(chain_file, &fd, &st)) {
+		/* ownership of fd is taken over by load function */
+		g = load_commit_graph_chain_fd_st(r, fd, &st);
+	}
+
+	free(chain_file);
+	return g;
+}
+
 /*
  * returns 1 if and only if all graphs in the chain have
  * corrected commit dates stored in the generation_data chunk.