While preparing commits to be written into a commit-graph file, compute
the generation numbers using a depth-first strategy.
The only commits that are walked in this depth-first search are those
without a precomputed generation number. Thus, computation time will be
relative to the number of new commits to the commit-graph file.
Signed-off-by: Derrick Stolee <dsto...@microsoft.com>
---
commit-graph.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
commit.h | 1 +
2 files changed, 47 insertions(+)
diff --git a/commit-graph.c b/commit-graph.c
index d24b947525..b80c8ad80e 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -419,6 +419,13 @@ static void write_graph_chunk_data(struct hashfile *f, int
hash_len,
else
packedDate[0] = 0;
+ if ((*list)->generation != GENERATION_NUMBER_UNDEF) {
+ if ((*list)->generation > GENERATION_NUMBER_MAX)
+ die("generation number %u is too large to store
in commit-graph",
+ (*list)->generation);
+ packedDate[0] |= htonl((*list)->generation << 2);
+ }
+
packedDate[1] = htonl((*list)->date);
hashwrite(f, packedDate, 8);
@@ -551,6 +558,43 @@ static void close_reachable(struct packed_oid_list *oids)
}
}
+static void compute_generation_numbers(struct commit** commits,
+ int nr_commits)
+{
+ int i;
+ struct commit_list *list = NULL;
+
+ for (i = 0; i < nr_commits; i++) {
+ if (commits[i]->generation != GENERATION_NUMBER_UNDEF &&
+ commits[i]->generation != GENERATION_NUMBER_NONE)
+ continue;
+
+ commit_list_insert(commits[i], &list);
+ while (list) {
+ struct commit *current = list->item;
+ struct commit_list *parent;
+ int all_parents_computed = 1;
+ uint32_t max_generation = 0;
+
+ for (parent = current->parents; parent; parent =
parent->next) {
+ if (parent->item->generation ==
GENERATION_NUMBER_UNDEF ||
+ parent->item->generation ==
GENERATION_NUMBER_NONE) {
+ all_parents_computed = 0;
+ commit_list_insert(parent->item, &list);
+ break;
+ } else if (parent->item->generation >
max_generation) {
+ max_generation =
parent->item->generation;
+ }
+ }
+
+ if (all_parents_computed) {
+ current->generation = max_generation + 1;
+ pop_commit(&list);
+ }
+ }
+ }
+}
+
void write_commit_graph(const char *obj_dir,
const char **pack_indexes,
int nr_packs,
@@ -674,6 +718,8 @@ void write_commit_graph(const char *obj_dir,
if (commits.nr >= GRAPH_PARENT_MISSING)
die(_("too many commits to write graph"));
+ compute_generation_numbers(commits.list, commits.nr);
+
graph_name = get_commit_graph_filename(obj_dir);
fd = hold_lock_file_for_update(&lk, graph_name, 0);
diff --git a/commit.h b/commit.h
index 3cadd386f3..bc7a3186c5 100644
--- a/commit.h
+++ b/commit.h
@@ -11,6 +11,7 @@
#define COMMIT_NOT_FROM_GRAPH 0xFFFFFFFF
#define GENERATION_NUMBER_UNDEF 0xFFFFFFFF
+#define GENERATION_NUMBER_MAX 0x3FFFFFFF
#define GENERATION_NUMBER_NONE 0
struct commit_list {
--
2.17.0.rc0
