1 files changed, 104 insertions, 35 deletions
diff --git a/commit-graph.c b/commit-graph.c
index 3fc1e0da27..b63a1fc85e 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -1,5 +1,6 @@
 #include "cache.h"
 #include "config.h"
+#include "dir.h"
 #include "git-compat-util.h"
 #include "lockfile.h"
 #include "pack.h"
@@ -248,9 +249,15 @@ static struct commit_list **insert_parent_or_die(struct commit_graph *g,
 	return &commit_list_insert(c, pptr)->next;
 }
 
+static void fill_commit_graph_info(struct commit *item, struct commit_graph *g, uint32_t pos)
+{
+	const unsigned char *commit_data = g->chunk_commit_data + GRAPH_DATA_WIDTH * pos;
+	item->graph_pos = pos;
+	item->generation = get_be32(commit_data + g->hash_len + 8) >> 2;
+}
+
 static int fill_commit_in_graph(struct commit *item, struct commit_graph *g, uint32_t pos)
 {
-	struct object_id oid;
 	uint32_t edge_value;
 	uint32_t *parent_data_ptr;
 	uint64_t date_low, date_high;
@@ -260,13 +267,14 @@ static int fill_commit_in_graph(struct commit *item, struct commit_graph *g, uin
 	item->object.parsed = 1;
 	item->graph_pos = pos;
 
-	hashcpy(oid.hash, commit_data);
-	item->tree = lookup_tree(&oid);
+	item->maybe_tree = NULL;
 
 	date_high = get_be32(commit_data + g->hash_len + 8) & 0x3;
 	date_low = get_be32(commit_data + g->hash_len + 12);
 	item->date = (timestamp_t)((date_high << 32) | date_low);
 
+	item->generation = get_be32(commit_data + g->hash_len + 8) >> 2;
+
 	pptr = &item->parents;
 
 	edge_value = get_be32(commit_data + g->hash_len);
@@ -295,29 +303,60 @@ static int fill_commit_in_graph(struct commit *item, struct commit_graph *g, uin
 	return 1;
 }
 
+static int find_commit_in_graph(struct commit *item, struct commit_graph *g, uint32_t *pos)
+{
+	if (item->graph_pos != COMMIT_NOT_FROM_GRAPH) {
+		*pos = item->graph_pos;
+		return 1;
+	} else {
+		return bsearch_graph(g, &(item->object.oid), pos);
+	}
+}
+
 int parse_commit_in_graph(struct commit *item)
 {
+	uint32_t pos;
+
 	if (!core_commit_graph)
 		return 0;
 	if (item->object.parsed)
 		return 1;
+	prepare_commit_graph();
+	if (commit_graph && find_commit_in_graph(item, commit_graph, &pos))
+		return fill_commit_in_graph(item, commit_graph, pos);
+	return 0;
+}
 
+void load_commit_graph_info(struct commit *item)
+{
+	uint32_t pos;
+	if (!core_commit_graph)
+		return;
 	prepare_commit_graph();
-	if (commit_graph) {
-		uint32_t pos;
-		int found;
-		if (item->graph_pos != COMMIT_NOT_FROM_GRAPH) {
-			pos = item->graph_pos;
-			found = 1;
-		} else {
-			found = bsearch_graph(commit_graph, &(item->object.oid), &pos);
-		}
+	if (commit_graph && find_commit_in_graph(item, commit_graph, &pos))
+		fill_commit_graph_info(item, commit_graph, pos);
+}
 
-		if (found)
-			return fill_commit_in_graph(item, commit_graph, pos);
-	}
+static struct tree *load_tree_for_commit(struct commit_graph *g, struct commit *c)
+{
+	struct object_id oid;
+	const unsigned char *commit_data = g->chunk_commit_data +
+					   GRAPH_DATA_WIDTH * (c->graph_pos);
 
-	return 0;
+	hashcpy(oid.hash, commit_data);
+	c->maybe_tree = lookup_tree(&oid);
+
+	return c->maybe_tree;
+}
+
+struct tree *get_commit_tree_in_graph(const struct commit *c)
+{
+	if (c->maybe_tree)
+		return c->maybe_tree;
+	if (c->graph_pos == COMMIT_NOT_FROM_GRAPH)
+		BUG("get_commit_tree_in_graph called from non-commit-graph commit");
+
+	return load_tree_for_commit(commit_graph, (struct commit *)c);
 }
 
 static void write_graph_chunk_fanout(struct hashfile *f,
@@ -372,7 +411,7 @@ static void write_graph_chunk_data(struct hashfile *f, int hash_len,
 		uint32_t packedDate[2];
 
 		parse_commit(*list);
-		hashwrite(f, (*list)->tree->object.oid.hash, hash_len);
+		hashwrite(f, get_commit_tree_oid(*list)->hash, hash_len);
 
 		parent = (*list)->parents;
 
@@ -420,6 +459,8 @@ static void write_graph_chunk_data(struct hashfile *f, int hash_len,
 		else
 			packedDate[0] = 0;
 
+		packedDate[0] |= htonl((*list)->generation << 2);
+
 		packedDate[1] = htonl((*list)->date);
 		hashwrite(f, packedDate, 8);
 
@@ -495,7 +536,7 @@ static int add_packed_commits(const struct object_id *oid,
 	struct object_info oi = OBJECT_INFO_INIT;
 
 	oi.typep = &type;
-	if (packed_object_info(pack, offset, &oi) < 0)
+	if (packed_object_info(the_repository, pack, offset, &oi) < 0)
 		die("unable to get type of object %s", oid_to_hex(oid));
 
 	if (type != OBJ_COMMIT)
@@ -552,6 +593,45 @@ static void close_reachable(struct packed_oid_list *oids)
 	}
 }
 
+static void compute_generation_numbers(struct packed_commit_list* commits)
+{
+	int i;
+	struct commit_list *list = NULL;
+
+	for (i = 0; i < commits->nr; i++) {
+		if (commits->list[i]->generation != GENERATION_NUMBER_INFINITY &&
+		    commits->list[i]->generation != GENERATION_NUMBER_ZERO)
+			continue;
+
+		commit_list_insert(commits->list[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_INFINITY ||
+				    parent->item->generation == GENERATION_NUMBER_ZERO) {
+					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);
+
+				if (current->generation > GENERATION_NUMBER_MAX)
+					current->generation = GENERATION_NUMBER_MAX;
+			}
+		}
+	}
+}
+
 void write_commit_graph(const char *obj_dir,
 			const char **pack_indexes,
 			int nr_packs,
@@ -564,7 +644,6 @@ void write_commit_graph(const char *obj_dir,
 	struct hashfile *f;
 	uint32_t i, count_distinct = 0;
 	char *graph_name;
-	int fd;
 	struct lock_file lk = LOCK_INIT;
 	uint32_t chunk_ids[5];
 	uint64_t chunk_offsets[5];
@@ -675,24 +754,14 @@ void write_commit_graph(const char *obj_dir,
 	if (commits.nr >= GRAPH_PARENT_MISSING)
 		die(_("too many commits to write graph"));
 
-	graph_name = get_commit_graph_filename(obj_dir);
-	fd = hold_lock_file_for_update(&lk, graph_name, 0);
-
-	if (fd < 0) {
-		struct strbuf folder = STRBUF_INIT;
-		strbuf_addstr(&folder, graph_name);
-		strbuf_setlen(&folder, strrchr(folder.buf, '/') - folder.buf);
-
-		if (mkdir(folder.buf, 0777) < 0)
-			die_errno(_("cannot mkdir %s"), folder.buf);
-		strbuf_release(&folder);
+	compute_generation_numbers(&commits);
 
-		fd = hold_lock_file_for_update(&lk, graph_name, LOCK_DIE_ON_ERROR);
-
-		if (fd < 0)
-			die_errno("unable to create '%s'", graph_name);
-	}
+	graph_name = get_commit_graph_filename(obj_dir);
+	if (safe_create_leading_directories(graph_name))
+		die_errno(_("unable to create leading directories of %s"),
+			  graph_name);
 
+	hold_lock_file_for_update(&lk, graph_name, LOCK_DIE_ON_ERROR);
 	f = hashfd(lk.tempfile->fd, lk.tempfile->filename.buf);
 
 	hashwrite_be32(f, GRAPH_SIGNATURE);