Merge branch 'jt/commit-graph-per-object-store'

The singleton commit-graph in-core instance is made per in-core
repository instance.

* jt/commit-graph-per-object-store:
  commit-graph: add repo arg to graph readers
  commit-graph: store graph in struct object_store
  commit-graph: add free_commit_graph
  commit-graph: add missing forward declaration
  object-store: add missing include
  commit-graph: refactor preparing commit graph

16 files changed, 207 insertions, 62 deletions

diff --git a/Makefile b/Makefile
index 74588d3dda..bc4fc8eeab 100644
--- a/Makefile
+++ b/Makefile
@@ -719,6 +719,7 @@ TEST_BUILTINS_OBJS += test-prio-queue.o
 TEST_BUILTINS_OBJS += test-read-cache.o
 TEST_BUILTINS_OBJS += test-ref-store.o
 TEST_BUILTINS_OBJS += test-regex.o
+TEST_BUILTINS_OBJS += test-repository.o
 TEST_BUILTINS_OBJS += test-revision-walking.o
 TEST_BUILTINS_OBJS += test-run-command.o
 TEST_BUILTINS_OBJS += test-scrap-cache-tree.o
diff --git a/builtin/commit-graph.c b/builtin/commit-graph.c
index c7d0db5ab4..0bf0c48657 100644
--- a/builtin/commit-graph.c
+++ b/builtin/commit-graph.c
@@ -115,6 +115,8 @@ static int graph_read(int argc, const char **argv)
 		printf(" large_edges");
 	printf("\n");
 
+	free_commit_graph(graph);
+
 	return 0;
 }
 
diff --git a/builtin/fsck.c b/builtin/fsck.c
index ea5e2a03e6..c96f3f4fcc 100644
--- a/builtin/fsck.c
+++ b/builtin/fsck.c
@@ -830,7 +830,7 @@ int cmd_fsck(int argc, const char **argv, const char *prefix)
 
 	check_connectivity();
 
-	if (core_commit_graph) {
+	if (!git_config_get_bool("core.commitgraph", &i) && i) {
 		struct child_process commit_graph_verify = CHILD_PROCESS_INIT;
 		const char *verify_argv[] = { "commit-graph", "verify", NULL, NULL, NULL };
 
diff --git a/cache.h b/cache.h
index 87785fc832..8dc7134f00 100644
--- a/cache.h
+++ b/cache.h
@@ -877,7 +877,6 @@ extern char *git_replace_ref_base;
 
 extern int fsync_object_files;
 extern int core_preload_index;
-extern int core_commit_graph;
 extern int core_apply_sparse_checkout;
 extern int precomposed_unicode;
 extern int protect_hfs;
diff --git a/commit-graph.c b/commit-graph.c
index 41a0133ff7..b0a55ad128 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -183,53 +183,60 @@ cleanup_fail:
 	exit(1);
 }
 
-/* global storage */
-static struct commit_graph *commit_graph = NULL;
-
-static void prepare_commit_graph_one(const char *obj_dir)
+static void prepare_commit_graph_one(struct repository *r, const char *obj_dir)
 {
 	char *graph_name;
 
-	if (commit_graph)
+	if (r->objects->commit_graph)
 		return;
 
 	graph_name = get_commit_graph_filename(obj_dir);
-	commit_graph = load_commit_graph_one(graph_name);
+	r->objects->commit_graph =
+		load_commit_graph_one(graph_name);
 
 	FREE_AND_NULL(graph_name);
 }
 
-static int prepare_commit_graph_run_once = 0;
-static void prepare_commit_graph(void)
+/*
+ * Return 1 if commit_graph is non-NULL, and 0 otherwise.
+ *
+ * On the first invocation, this function attemps to load the commit
+ * graph if the_repository is configured to have one.
+ */
+static int prepare_commit_graph(struct repository *r)
 {
 	struct alternate_object_database *alt;
 	char *obj_dir;
+	int config_value;
 
-	if (prepare_commit_graph_run_once)
-		return;
-	prepare_commit_graph_run_once = 1;
+	if (r->objects->commit_graph_attempted)
+		return !!r->objects->commit_graph;
+	r->objects->commit_graph_attempted = 1;
 
-	obj_dir = get_object_directory();
-	prepare_commit_graph_one(obj_dir);
-	prepare_alt_odb(the_repository);
-	for (alt = the_repository->objects->alt_odb_list;
-	     !commit_graph && alt;
+	if (repo_config_get_bool(r, "core.commitgraph", &config_value) ||
+	    !config_value)
+		/*
+		 * This repository is not configured to use commit graphs, so
+		 * do not load one. (But report commit_graph_attempted anyway
+		 * so that commit graph loading is not attempted again for this
+		 * repository.)
+		 */
+		return 0;
+
+	obj_dir = r->objects->objectdir;
+	prepare_commit_graph_one(r, obj_dir);
+	prepare_alt_odb(r);
+	for (alt = r->objects->alt_odb_list;
+	     !r->objects->commit_graph && alt;
 	     alt = alt->next)
-		prepare_commit_graph_one(alt->path);
+		prepare_commit_graph_one(r, alt->path);
+	return !!r->objects->commit_graph;
 }
 
 static void close_commit_graph(void)
 {
-	if (!commit_graph)
-		return;
-
-	if (commit_graph->graph_fd >= 0) {
-		munmap((void *)commit_graph->data, commit_graph->data_len);
-		commit_graph->data = NULL;
-		close(commit_graph->graph_fd);
-	}
-
-	FREE_AND_NULL(commit_graph);
+	free_commit_graph(the_repository->objects->commit_graph);
+	the_repository->objects->commit_graph = NULL;
 }
 
 static int bsearch_graph(struct commit_graph *g, struct object_id *oid, uint32_t *pos)
@@ -324,8 +331,6 @@ static int parse_commit_in_graph_one(struct commit_graph *g, struct commit *item
 {
 	uint32_t pos;
 
-	if (!core_commit_graph)
-		return 0;
 	if (item->object.parsed)
 		return 1;
 
@@ -335,25 +340,20 @@ static int parse_commit_in_graph_one(struct commit_graph *g, struct commit *item
 	return 0;
 }
 
-int parse_commit_in_graph(struct commit *item)
+int parse_commit_in_graph(struct repository *r, struct commit *item)
 {
-	if (!core_commit_graph)
+	if (!prepare_commit_graph(r))
 		return 0;
-
-	prepare_commit_graph();
-	if (commit_graph)
-		return parse_commit_in_graph_one(commit_graph, item);
-	return 0;
+	return parse_commit_in_graph_one(r->objects->commit_graph, item);
 }
 
-void load_commit_graph_info(struct commit *item)
+void load_commit_graph_info(struct repository *r, struct commit *item)
 {
 	uint32_t pos;
-	if (!core_commit_graph)
+	if (!prepare_commit_graph(r))
 		return;
-	prepare_commit_graph();
-	if (commit_graph && find_commit_in_graph(item, commit_graph, &pos))
-		fill_commit_graph_info(item, commit_graph, pos);
+	if (find_commit_in_graph(item, r->objects->commit_graph, &pos))
+		fill_commit_graph_info(item, r->objects->commit_graph, pos);
 }
 
 static struct tree *load_tree_for_commit(struct commit_graph *g, struct commit *c)
@@ -379,9 +379,9 @@ static struct tree *get_commit_tree_in_graph_one(struct commit_graph *g,
 	return load_tree_for_commit(g, (struct commit *)c);
 }
 
-struct tree *get_commit_tree_in_graph(const struct commit *c)
+struct tree *get_commit_tree_in_graph(struct repository *r, const struct commit *c)
 {
-	return get_commit_tree_in_graph_one(commit_graph, c);
+	return get_commit_tree_in_graph_one(r->objects->commit_graph, c);
 }
 
 static void write_graph_chunk_fanout(struct hashfile *f,
@@ -697,16 +697,18 @@ void write_commit_graph(const char *obj_dir,
 	oids.alloc = approximate_object_count() / 4;
 
 	if (append) {
-		prepare_commit_graph_one(obj_dir);
-		if (commit_graph)
-			oids.alloc += commit_graph->num_commits;
+		prepare_commit_graph_one(the_repository, obj_dir);
+		if (the_repository->objects->commit_graph)
+			oids.alloc += the_repository->objects->commit_graph->num_commits;
 	}
 
 	if (oids.alloc < 1024)
 		oids.alloc = 1024;
 	ALLOC_ARRAY(oids.list, oids.alloc);
 
-	if (append && commit_graph) {
+	if (append && the_repository->objects->commit_graph) {
+		struct commit_graph *commit_graph =
+			the_repository->objects->commit_graph;
 		for (i = 0; i < commit_graph->num_commits; i++) {
 			const unsigned char *hash = commit_graph->chunk_oid_lookup +
 				commit_graph->hash_len * i;
@@ -1027,3 +1029,15 @@ int verify_commit_graph(struct repository *r, struct commit_graph *g)
 
 	return verify_commit_graph_error;
 }
+
+void free_commit_graph(struct commit_graph *g)
+{
+	if (!g)
+		return;
+	if (g->graph_fd >= 0) {
+		munmap((void *)g->data, g->data_len);
+		g->data = NULL;
+		close(g->graph_fd);
+	}
+	free(g);
+}
diff --git a/commit-graph.h b/commit-graph.h
index 506cb45fb1..76e098934a 100644
--- a/commit-graph.h
+++ b/commit-graph.h
@@ -5,6 +5,8 @@
 #include "repository.h"
 #include "string-list.h"
 
+struct commit;
+
 char *get_commit_graph_filename(const char *obj_dir);
 
 /*
@@ -17,7 +19,7 @@ char *get_commit_graph_filename(const char *obj_dir);
  *
  * See parse_commit_buffer() for the fallback after this call.
  */
-int parse_commit_in_graph(struct commit *item);
+int parse_commit_in_graph(struct repository *r, struct commit *item);
 
 /*
  * It is possible that we loaded commit contents from the commit buffer,
@@ -25,9 +27,10 @@ int parse_commit_in_graph(struct commit *item);
  * checked and filled. Fill the graph_pos and generation members of
  * the given commit.
  */
-void load_commit_graph_info(struct commit *item);
+void load_commit_graph_info(struct repository *r, struct commit *item);
 
-struct tree *get_commit_tree_in_graph(const struct commit *c);
+struct tree *get_commit_tree_in_graph(struct repository *r,
+				      const struct commit *c);
 
 struct commit_graph {
 	int graph_fd;
@@ -56,4 +59,6 @@ void write_commit_graph(const char *obj_dir,
 
 int verify_commit_graph(struct repository *r, struct commit_graph *g);
 
+void free_commit_graph(struct commit_graph *);
+
 #endif
diff --git a/commit.c b/commit.c
index add310d423..30d1af2b20 100644
--- a/commit.c
+++ b/commit.c
@@ -342,7 +342,7 @@ struct tree *get_commit_tree(const struct commit *commit)
 	if (commit->graph_pos == COMMIT_NOT_FROM_GRAPH)
 		BUG("commit has NULL tree, but was not loaded from commit-graph");
 
-	return get_commit_tree_in_graph(commit);
+	return get_commit_tree_in_graph(the_repository, commit);
 }
 
 struct object_id *get_commit_tree_oid(const struct commit *commit)
@@ -438,7 +438,7 @@ int parse_commit_buffer(struct repository *r, struct commit *item, const void *b
 	item->date = parse_commit_date(bufptr, tail);
 
 	if (check_graph)
-		load_commit_graph_info(item);
+		load_commit_graph_info(the_repository, item);
 
 	return 0;
 }
@@ -454,7 +454,7 @@ int parse_commit_internal(struct commit *item, int quiet_on_missing, int use_com
 		return -1;
 	if (item->object.parsed)
 		return 0;
-	if (use_commit_graph && parse_commit_in_graph(item))
+	if (use_commit_graph && parse_commit_in_graph(the_repository, item))
 		return 0;
 	buffer = read_object_file(&item->object.oid, &type, &size);
 	if (!buffer)
diff --git a/config.c b/config.c
index 35a9bc7955..66645047eb 100644
--- a/config.c
+++ b/config.c
@@ -1320,11 +1320,6 @@ static int git_default_core_config(const char *var, const char *value)
 		return 0;
 	}
 
-	if (!strcmp(var, "core.commitgraph")) {
-		core_commit_graph = git_config_bool(var, value);
-		return 0;
-	}
-
 	if (!strcmp(var, "core.sparsecheckout")) {
 		core_apply_sparse_checkout = git_config_bool(var, value);
 		return 0;
diff --git a/environment.c b/environment.c
index 013e845235..6cf0079389 100644
--- a/environment.c
+++ b/environment.c
@@ -66,7 +66,6 @@ enum push_default_type push_default = PUSH_DEFAULT_UNSPECIFIED;
 enum object_creation_mode object_creation_mode = OBJECT_CREATION_MODE;
 char *notes_ref_name;
 int grafts_replace_parents = 1;
-int core_commit_graph;
 int core_apply_sparse_checkout;
 int merge_log_config = -1;
 int precomposed_unicode = -1; /* see probe_utf8_pathname_composition() */
diff --git a/object-store.h b/object-store.h
index a3db17bbf5..e481f7ad41 100644
--- a/object-store.h
+++ b/object-store.h
@@ -2,6 +2,9 @@
 #define OBJECT_STORE_H
 
 #include "oidmap.h"
+#include "list.h"
+#include "sha1-array.h"
+#include "strbuf.h"
 
 struct alternate_object_database {
 	struct alternate_object_database *next;
@@ -103,6 +106,9 @@ struct raw_object_store {
 	 */
 	struct oidmap *replace_map;
 
+	struct commit_graph *commit_graph;
+	unsigned commit_graph_attempted : 1; /* if loading has been attempted */
+
 	/*
 	 * private data
 	 *
diff --git a/object.c b/object.c
index b0faab85d4..e2c112cc1a 100644
--- a/object.c
+++ b/object.c
@@ -9,6 +9,7 @@
 #include "alloc.h"
 #include "object-store.h"
 #include "packfile.h"
+#include "commit-graph.h"
 
 unsigned int get_max_object_index(void)
 {
@@ -507,6 +508,10 @@ void raw_object_store_clear(struct raw_object_store *o)
 	oidmap_free(o->replace_map, 1);
 	FREE_AND_NULL(o->replace_map);
 
+	free_commit_graph(o->commit_graph);
+	o->commit_graph = NULL;
+	o->commit_graph_attempted = 0;
+
 	free_alt_odbs(o);
 	o->alt_odb_tail = NULL;
 
diff --git a/ref-filter.c b/ref-filter.c
index 600774de68..a8def7b3a3 100644
--- a/ref-filter.c
+++ b/ref-filter.c
@@ -1713,7 +1713,7 @@ static enum contains_result contains_tag_algo(struct commit *candidate,
 
 	for (p = want; p; p = p->next) {
 		struct commit *c = p->item;
-		load_commit_graph_info(c);
+		load_commit_graph_info(the_repository, c);
 		if (c->generation < cutoff)
 			cutoff = c->generation;
 	}
diff --git a/t/helper/test-repository.c b/t/helper/test-repository.c
new file mode 100644
index 0000000000..2762ca6562
--- /dev/null
+++ b/t/helper/test-repository.c
@@ -0,0 +1,82 @@
+#include "test-tool.h"
+#include "cache.h"
+#include "commit-graph.h"
+#include "commit.h"
+#include "config.h"
+#include "object-store.h"
+#include "object.h"
+#include "repository.h"
+#include "tree.h"
+
+static void test_parse_commit_in_graph(const char *gitdir, const char *worktree,
+				       const struct object_id *commit_oid)
+{
+	struct repository r;
+	struct commit *c;
+	struct commit_list *parent;
+
+	repo_init(&r, gitdir, worktree);
+
+	c = lookup_commit(&r, commit_oid);
+
+	if (!parse_commit_in_graph(&r, c))
+		die("Couldn't parse commit");
+
+	printf("%"PRItime, c->date);
+	for (parent = c->parents; parent; parent = parent->next)
+		printf(" %s", oid_to_hex(&parent->item->object.oid));
+	printf("\n");
+
+	repo_clear(&r);
+}
+
+static void test_get_commit_tree_in_graph(const char *gitdir,
+					  const char *worktree,
+					  const struct object_id *commit_oid)
+{
+	struct repository r;
+	struct commit *c;
+	struct tree *tree;
+
+	repo_init(&r, gitdir, worktree);
+
+	c = lookup_commit(&r, commit_oid);
+
+	/*
+	 * get_commit_tree_in_graph does not automatically parse the commit, so
+	 * parse it first.
+	 */
+	if (!parse_commit_in_graph(&r, c))
+		die("Couldn't parse commit");
+	tree = get_commit_tree_in_graph(&r, c);
+	if (!tree)
+		die("Couldn't get commit tree");
+
+	printf("%s\n", oid_to_hex(&tree->object.oid));
+
+	repo_clear(&r);
+}
+
+int cmd__repository(int argc, const char **argv)
+{
+	if (argc < 2)
+		die("must have at least 2 arguments");
+	if (!strcmp(argv[1], "parse_commit_in_graph")) {
+		struct object_id oid;
+		if (argc < 5)
+			die("not enough arguments");
+		if (parse_oid_hex(argv[4], &oid, &argv[4]))
+			die("cannot parse oid '%s'", argv[4]);
+		test_parse_commit_in_graph(argv[2], argv[3], &oid);
+	} else if (!strcmp(argv[1], "get_commit_tree_in_graph")) {
+		struct object_id oid;
+		if (argc < 5)
+			die("not enough arguments");
+		if (parse_oid_hex(argv[4], &oid, &argv[4]))
+			die("cannot parse oid '%s'", argv[4]);
+		test_get_commit_tree_in_graph(argv[2], argv[3], &oid);
+	} else {
+		die("unrecognized '%s'", argv[1]);
+	}
+	return 0;
+}
diff --git a/t/helper/test-tool.c b/t/helper/test-tool.c
index 805a45de9c..dafc91c240 100644
--- a/t/helper/test-tool.c
+++ b/t/helper/test-tool.c
@@ -29,6 +29,7 @@ static struct test_cmd cmds[] = {
 	{ "read-cache", cmd__read_cache },
 	{ "ref-store", cmd__ref_store },
 	{ "regex", cmd__regex },
+	{ "repository", cmd__repository },
 	{ "revision-walking", cmd__revision_walking },
 	{ "run-command", cmd__run_command },
 	{ "scrap-cache-tree", cmd__scrap_cache_tree },
diff --git a/t/helper/test-tool.h b/t/helper/test-tool.h
index 7116ddfb94..80cbcf0857 100644
--- a/t/helper/test-tool.h
+++ b/t/helper/test-tool.h
@@ -23,6 +23,7 @@ int cmd__prio_queue(int argc, const char **argv);
 int cmd__read_cache(int argc, const char **argv);
 int cmd__ref_store(int argc, const char **argv);
 int cmd__regex(int argc, const char **argv);
+int cmd__repository(int argc, const char **argv);
 int cmd__revision_walking(int argc, const char **argv);
 int cmd__run_command(int argc, const char **argv);
 int cmd__scrap_cache_tree(int argc, const char **argv);
diff --git a/t/t5318-commit-graph.sh b/t/t5318-commit-graph.sh
index 5947de3d24..4f17d7701e 100755
--- a/t/t5318-commit-graph.sh
+++ b/t/t5318-commit-graph.sh
@@ -431,4 +431,39 @@ test_expect_success 'git fsck (checks commit-graph)' '
 	test_must_fail git fsck
 '
 
+test_expect_success 'setup non-the_repository tests' '
+	rm -rf repo &&
+	git init repo &&
+	test_commit -C repo one &&
+	test_commit -C repo two &&
+	git -C repo config core.commitGraph true &&
+	git -C repo rev-parse two | \
+		git -C repo commit-graph write --stdin-commits
+'
+
+test_expect_success 'parse_commit_in_graph works for non-the_repository' '
+	test-tool repository parse_commit_in_graph \
+		repo/.git repo "$(git -C repo rev-parse two)" >actual &&
+	echo $(git -C repo log --pretty="%ct" -1) \
+		$(git -C repo rev-parse one) >expect &&
+	test_cmp expect actual &&
+
+	test-tool repository parse_commit_in_graph \
+		repo/.git repo "$(git -C repo rev-parse one)" >actual &&
+	echo $(git -C repo log --pretty="%ct" -1 one) >expect &&
+	test_cmp expect actual
+'
+
+test_expect_success 'get_commit_tree_in_graph works for non-the_repository' '
+	test-tool repository get_commit_tree_in_graph \
+		repo/.git repo "$(git -C repo rev-parse two)" >actual &&
+	echo $(git -C repo rev-parse two^{tree}) >expect &&
+	test_cmp expect actual &&
+
+	test-tool repository get_commit_tree_in_graph \
+		repo/.git repo "$(git -C repo rev-parse one)" >actual &&
+	echo $(git -C repo rev-parse one^{tree}) >expect &&
+	test_cmp expect actual
+'
+
 test_done