commit-graph: compute generation numbers
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. If a computed generation number would exceed GENERATION_NUMBER_MAX, then use GENERATION_NUMBER_MAX instead. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Derrick Stolee committed
May 1, 2018 at 12:47 UTC
3258c66332abaf6e3e8fd81cab07ae804760cd08
1 file changed
+43
commit-graph.c
+43
@@ -439,6 +439,8 @@ static void write_graph_chunk_data(struct hashfile *f, int hash_len,
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else
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packedDate[0] = 0;
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+ packedDate[0] |= htonl((*list)->generation << 2);
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+
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packedDate[1] = htonl((*list)->date);
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hashwrite(f, packedDate, 8);
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@@ -571,6 +573,45 @@ static void close_reachable(struct packed_oid_list *oids)
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}
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}
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+static void compute_generation_numbers(struct packed_commit_list* commits)
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+{
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+ int i;
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+ struct commit_list *list = NULL;
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+
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+ for (i = 0; i < commits->nr; i++) {
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+ if (commits->list[i]->generation != GENERATION_NUMBER_INFINITY &&
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+ commits->list[i]->generation != GENERATION_NUMBER_ZERO)
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+ continue;
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+
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+ commit_list_insert(commits->list[i], &list);
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+ while (list) {
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+ struct commit *current = list->item;
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+ struct commit_list *parent;
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+ int all_parents_computed = 1;
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+ uint32_t max_generation = 0;
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+
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+ for (parent = current->parents; parent; parent = parent->next) {
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+ if (parent->item->generation == GENERATION_NUMBER_INFINITY ||
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+ parent->item->generation == GENERATION_NUMBER_ZERO) {
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+ all_parents_computed = 0;
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+ commit_list_insert(parent->item, &list);
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+ break;
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+ } else if (parent->item->generation > max_generation) {
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+ max_generation = parent->item->generation;
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+ }
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+ }
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+
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+ if (all_parents_computed) {
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+ current->generation = max_generation + 1;
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+ pop_commit(&list);
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+
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+ if (current->generation > GENERATION_NUMBER_MAX)
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+ current->generation = GENERATION_NUMBER_MAX;
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+ }
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+ }
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+ }
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+}
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+
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void write_commit_graph(const char *obj_dir,
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const char **pack_indexes,
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int nr_packs,
@@ -694,6 +735,8 @@ void write_commit_graph(const char *obj_dir,
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if (commits.nr >= GRAPH_PARENT_MISSING)
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die(_("too many commits to write graph"));
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+ compute_generation_numbers(&commits);
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+
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graph_name = get_commit_graph_filename(obj_dir);
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fd = hold_lock_file_for_update(&lk, graph_name, 0);
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