Merge branch 'ds/reachable'

The code for computing history reachability has been shuffled,
obtained a bunch of new tests to cover them, and then being
improved.

* ds/reachable:
  commit-reach: correct accidental #include of C file
  commit-reach: use can_all_from_reach
  commit-reach: make can_all_from_reach... linear
  commit-reach: replace ref_newer logic
  test-reach: test commit_contains
  test-reach: test can_all_from_reach_with_flags
  test-reach: test reduce_heads
  test-reach: test get_merge_bases_many
  test-reach: test is_descendant_of
  test-reach: test in_merge_bases
  test-reach: create new test tool for ref_newer
  commit-reach: move can_all_from_reach_with_flags
  upload-pack: generalize commit date cutoff
  upload-pack: refactor ok_to_give_up()
  upload-pack: make reachable() more generic
  commit-reach: move commit_contains from ref-filter
  commit-reach: move ref_newer from remote.c
  commit.h: remove method declarations
  commit-reach: move walk methods from commit.c

1 files changed, 18 insertions, 0 deletions

diff --git a/commit-graph.c b/commit-graph.c
index 8a1bec7b8a..0cad55eec2 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -233,6 +233,24 @@ static int prepare_commit_graph(struct repository *r)
 	return !!r->objects->commit_graph;
 }
 
+int generation_numbers_enabled(struct repository *r)
+{
+	uint32_t first_generation;
+	struct commit_graph *g;
+	if (!prepare_commit_graph(r))
+	       return 0;
+
+	g = r->objects->commit_graph;
+
+	if (!g->num_commits)
+		return 0;
+
+	first_generation = get_be32(g->chunk_commit_data +
+				    g->hash_len + 8) >> 2;
+
+	return !!first_generation;
+}
+
 static void close_commit_graph(void)
 {
 	free_commit_graph(the_repository->objects->commit_graph);