Re: [PATCH 6/6] commit-graph: implement corrected commit date offset

Signed-off-by: Abhishek Kumar <redacted>
---
 blame.c                 |   2 +-
 commit-graph.c          | 109 ++++++++++++++++++++++------------------
 commit-graph.h          |   4 +-
 commit-reach.c          |  32 ++++++------
 commit-reach.h          |   2 +-
 commit.h                |   3 ++
 revision.c              |  14 +++---
 t/t5318-commit-graph.sh |   2 +-
 upload-pack.c           |   2 +-
 9 files changed, 93 insertions(+), 77 deletions(-)

diff --git a/blame.c b/blame.c
index 82fa16d658..48aa632461 100644
--- a/blame.c
+++ b/blame.c

@@ -1272,7 +1272,7 @@ static int maybe_changed_path(struct repository *r,
 	if (!bd)
 		return 1;
 
-	if (commit_graph_generation(origin->commit) == GENERATION_NUMBER_INFINITY)
+	if (commit_graph_generation(origin->commit) == GENERATION_NUMBER_V2_INFINITY)
 		return 1;

-static void compute_generation_numbers(struct write_commit_graph_context *ctx)
+static void compute_corrected_commit_date_offsets(struct write_commit_graph_context *ctx)
 {
 	int i;
 	struct commit_list *list = NULL;

@@ -1326,11 +1334,11 @@ static void compute_generation_numbers(struct write_commit_graph_context *ctx)
 					_("Computing commit graph generation numbers"),
 					ctx->commits.nr);
 	for (i = 0; i < ctx->commits.nr; i++) {
-		uint32_t generation = commit_graph_data_at(ctx->commits.list[i])->generation;
+		uint32_t topo_level = *topo_level_slab_at(ctx->topo_levels, ctx->commits.list[i]);
 
 		display_progress(ctx->progress, i + 1);
-		if (generation != GENERATION_NUMBER_INFINITY &&
-		    generation != GENERATION_NUMBER_ZERO)
+		if (topo_level != GENERATION_NUMBER_INFINITY &&
+		    topo_level != GENERATION_NUMBER_ZERO)
 			continue;

 		commit_list_insert(ctx->commits.list[i], &list);

@@ -1338,29 +1346,38 @@ static void compute_generation_numbers(struct write_commit_graph_context *ctx)
 			struct commit *current = list->item;
 			struct commit_list *parent;
 			int all_parents_computed = 1;
-			uint32_t max_generation = 0;
+			uint32_t max_level = 0;
+			timestamp_t max_corrected_commit_date = current->date;

 
 			for (parent = current->parents; parent; parent = parent->next) {
-				generation = commit_graph_data_at(parent->item)->generation;
+				topo_level = *topo_level_slab_at(ctx->topo_levels, parent->item);
 
-				if (generation == GENERATION_NUMBER_INFINITY ||
-				    generation == GENERATION_NUMBER_ZERO) {
+				if (topo_level == GENERATION_NUMBER_INFINITY ||
+				    topo_level == GENERATION_NUMBER_ZERO) {
 					all_parents_computed = 0;
 					commit_list_insert(parent->item, &list);
 					break;
-				} else if (generation > max_generation) {
-					max_generation = generation;
+				} else {
+					struct commit_graph_data *data = commit_graph_data_at(parent->item);
+
+					if (topo_level > max_level)
+						max_level = topo_level;
+
+					if (data->generation > max_corrected_commit_date)
+						max_corrected_commit_date = data->generation;
 				}
 			}
 
 			if (all_parents_computed) {
 				struct commit_graph_data *data = commit_graph_data_at(current);
 
-				data->generation = max_generation + 1;
-				pop_commit(&list);
+				if (max_level > GENERATION_NUMBER_MAX - 1)
+					max_level = GENERATION_NUMBER_MAX - 1;
+
+				*topo_level_slab_at(ctx->topo_levels, current) = max_level + 1;
+				data->generation = max_corrected_commit_date + 1;
 
-				if (data->generation > GENERATION_NUMBER_MAX)
-					data->generation = GENERATION_NUMBER_MAX;
+				pop_commit(&list);
 			}
 		}
 	}

@@ -2085,6 +2102,7 @@ int write_commit_graph(struct object_directory *odb,
 	uint32_t i, count_distinct = 0;
 	int res = 0;
 	int replace = 0;
+	struct topo_level_slab topo_levels;
 
 	if (!commit_graph_compatible(the_repository))
 		return 0;

@@ -2099,6 +2117,9 @@ int write_commit_graph(struct object_directory *odb,
 	ctx->changed_paths = flags & COMMIT_GRAPH_WRITE_BLOOM_FILTERS ? 1 : 0;
 	ctx->total_bloom_filter_data_size = 0;
 
+	init_topo_level_slab(&topo_levels);
+	ctx->topo_levels = &topo_levels;
+
 	if (ctx->split) {
 		struct commit_graph *g;
 		prepare_commit_graph(ctx->r);

@@ -2197,7 +2218,7 @@ int write_commit_graph(struct object_directory *odb,
 	} else
 		ctx->num_commit_graphs_after = 1;
 
-	compute_generation_numbers(ctx);
+	compute_corrected_commit_date_offsets(ctx);