object-store: rename object_directory to odb_source

The `object_directory` structure is used as an access point for a single
object directory like ".git/objects". While the structure isn't yet
fully self-contained, the intent is for it to eventually contain all
information required to access objects in one specific location.

While the name "object directory" is a good fit for now, this will
change over time as we continue with the agenda to make pluggable object
databases a thing. Eventually, objects may not be accessed via any kind
of directory at all anymore, but they could instead be backed by any
kind of durable storage mechanism. While it seems quite far-fetched for
now, it is thinkable that eventually this might even be some form of a
database, for example.

As such, the current name of this structure will become worse over time
as we evolve into the direction of pluggable ODBs. Immediate next steps
will start to carve out proper self-contained object directories, which
requires us to pass in these object directories as parameters. Based on
our modern naming schema this means that those functions should then be
named after their subsystem, which means that we would start to bake the
current name into the codebase more and more.

Let's preempt this by renaming the structure. There have been a couple
alternatives that were discussed:

  - `odb_backend` was discarded because it led to the association that
    one object database has a single backend, but the model is that one
    alternate has one backend. Furthermore, "backend" is more about the
    actual backing implementation and less about the high-level concept.

  - `odb_alternate` was discarded because it is a bit of a stretch to
    also call the main object directory an "alternate".

Instead, pick `odb_source` as the new name. It makes it sufficiently
clear that there can be multiple sources and does not cause confusion
when mixed with the already-existing "alternate" terminology.

In the future, this change allows us to easily introduce for example a
`odb_files_source` and other format-specific implementations.

Signed-off-by: Patrick Steinhardt <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: pks-t

builtin/commit-graph.c

@@ -66,7 +66,7 @@ static int graph_verify(int argc, const char **argv, const char *prefix,
 			struct repository *repo UNUSED)
 {
 	struct commit_graph *graph = NULL;
-	struct object_directory *odb = NULL;
+	struct odb_source *source = NULL;
 	char *graph_name;
 	char *chain_name;
 	enum { OPENED_NONE, OPENED_GRAPH, OPENED_CHAIN } opened = OPENED_NONE;
@@ -101,9 +101,9 @@ static int graph_verify(int argc, const char **argv, const char *prefix,
 	if (opts.progress)
 		flags |= COMMIT_GRAPH_WRITE_PROGRESS;
 
-	odb = find_odb(the_repository, opts.obj_dir);
-	graph_name = get_commit_graph_filename(odb);
-	chain_name = get_commit_graph_chain_filename(odb);
+	source = find_odb(the_repository, opts.obj_dir);
+	graph_name = get_commit_graph_filename(source);
+	chain_name = get_commit_graph_chain_filename(source);
 	if (open_commit_graph(graph_name, &fd, &st))
 		opened = OPENED_GRAPH;
 	else if (errno != ENOENT)
@@ -120,7 +120,7 @@ static int graph_verify(int argc, const char **argv, const char *prefix,
 	if (opened == OPENED_NONE)
 		return 0;
 	else if (opened == OPENED_GRAPH)
-		graph = load_commit_graph_one_fd_st(the_repository, fd, &st, odb);
+		graph = load_commit_graph_one_fd_st(the_repository, fd, &st, source);
 	else
 		graph = load_commit_graph_chain_fd_st(the_repository, fd, &st,
 						      &incomplete_chain);
@@ -221,7 +221,7 @@ static int graph_write(int argc, const char **argv, const char *prefix,
 	struct string_list pack_indexes = STRING_LIST_INIT_DUP;
 	struct strbuf buf = STRBUF_INIT;
 	struct oidset commits = OIDSET_INIT;
-	struct object_directory *odb = NULL;
+	struct odb_source *source = NULL;
 	int result = 0;
 	enum commit_graph_write_flags flags = 0;
 	struct progress *progress = NULL;
@@ -289,10 +289,10 @@ static int graph_write(int argc, const char **argv, const char *prefix,
 	    git_env_bool(GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS, 0))
 		flags |= COMMIT_GRAPH_WRITE_BLOOM_FILTERS;
 
-	odb = find_odb(the_repository, opts.obj_dir);
+	source = find_odb(the_repository, opts.obj_dir);
 
 	if (opts.reachable) {
-		if (write_commit_graph_reachable(odb, flags, &write_opts))
+		if (write_commit_graph_reachable(source, flags, &write_opts))
 			result = 1;
 		goto cleanup;
 	}
@@ -318,7 +318,7 @@ static int graph_write(int argc, const char **argv, const char *prefix,
 		stop_progress(&progress);
 	}
 
-	if (write_commit_graph(odb,
+	if (write_commit_graph(source,
 			       opts.stdin_packs ? &pack_indexes : NULL,
 			       opts.stdin_commits ? &commits : NULL,
 			       flags,

builtin/count-objects.c

@@ -80,10 +80,10 @@ static int count_cruft(const char *basename UNUSED, const char *path,
 	return 0;
 }
 
-static int print_alternate(struct object_directory *odb, void *data UNUSED)
+static int print_alternate(struct odb_source *alternate, void *data UNUSED)
 {
 	printf("alternate: ");
-	quote_c_style(odb->path, NULL, stdout, 0);
+	quote_c_style(alternate->path, NULL, stdout, 0);
 	putchar('\n');
 	return 0;
 }

builtin/fetch.c

@@ -2653,7 +2653,7 @@ int cmd_fetch(int argc,
 			commit_graph_flags |= COMMIT_GRAPH_WRITE_PROGRESS;
 
 		trace2_region_enter("fetch", "write-commit-graph", the_repository);
-		write_commit_graph_reachable(the_repository->objects->odb,
+		write_commit_graph_reachable(the_repository->objects->sources,
 					     commit_graph_flags,
 					     NULL);
 		trace2_region_leave("fetch", "write-commit-graph", the_repository);

builtin/fsck.c

@@ -956,7 +956,7 @@ int cmd_fsck(int argc,
 	     struct repository *repo UNUSED)
 {
 	int i;
-	struct object_directory *odb;
+	struct odb_source *source;
 
 	/* fsck knows how to handle missing promisor objects */
 	fetch_if_missing = 0;
@@ -998,8 +998,8 @@ int cmd_fsck(int argc,
 				       mark_packed_for_connectivity, NULL, 0);
 	} else {
 		prepare_alt_odb(the_repository);
-		for (odb = the_repository->objects->odb; odb; odb = odb->next)
-			fsck_object_dir(odb->path);
+		for (source = the_repository->objects->sources; source; source = source->next)
+			fsck_object_dir(source->path);
 
 		if (check_full) {
 			struct packed_git *p;
@@ -1109,11 +1109,11 @@ int cmd_fsck(int argc,
 		struct child_process commit_graph_verify = CHILD_PROCESS_INIT;
 
 		prepare_alt_odb(the_repository);
-		for (odb = the_repository->objects->odb; odb; odb = odb->next) {
+		for (source = the_repository->objects->sources; source; source = source->next) {
 			child_process_init(&commit_graph_verify);
 			commit_graph_verify.git_cmd = 1;
 			strvec_pushl(&commit_graph_verify.args, "commit-graph",
-				     "verify", "--object-dir", odb->path, NULL);
+				     "verify", "--object-dir", source->path, NULL);
 			if (show_progress)
 				strvec_push(&commit_graph_verify.args, "--progress");
 			else
@@ -1127,11 +1127,11 @@ int cmd_fsck(int argc,
 		struct child_process midx_verify = CHILD_PROCESS_INIT;
 
 		prepare_alt_odb(the_repository);
-		for (odb = the_repository->objects->odb; odb; odb = odb->next) {
+		for (source = the_repository->objects->sources; source; source = source->next) {
 			child_process_init(&midx_verify);
 			midx_verify.git_cmd = 1;
 			strvec_pushl(&midx_verify.args, "multi-pack-index",
-				     "verify", "--object-dir", odb->path, NULL);
+				     "verify", "--object-dir", source->path, NULL);
 			if (show_progress)
 				strvec_push(&midx_verify.args, "--progress");
 			else

builtin/gc.c

@@ -1018,7 +1018,7 @@ int cmd_gc(int argc,
 	}
 
 	if (the_repository->settings.gc_write_commit_graph == 1)
-		write_commit_graph_reachable(the_repository->objects->odb,
+		write_commit_graph_reachable(the_repository->objects->sources,
 					     !quiet && !daemonized ? COMMIT_GRAPH_WRITE_PROGRESS : 0,
 					     NULL);
 
@@ -1271,7 +1271,7 @@ static int loose_object_auto_condition(struct gc_config *cfg UNUSED)
 	if (loose_object_auto_limit < 0)
 		return 1;
 
-	return for_each_loose_file_in_objdir(the_repository->objects->odb->path,
+	return for_each_loose_file_in_objdir(the_repository->objects->sources->path,
 					     loose_object_count,
 					     NULL, NULL, &count);
 }
@@ -1306,7 +1306,7 @@ static int pack_loose(struct maintenance_run_opts *opts)
 	 * Do not start pack-objects process
 	 * if there are no loose objects.
 	 */
-	if (!for_each_loose_file_in_objdir(r->objects->odb->path,
+	if (!for_each_loose_file_in_objdir(r->objects->sources->path,
 					   bail_on_loose,
 					   NULL, NULL, NULL))
 		return 0;
@@ -1318,7 +1318,7 @@ static int pack_loose(struct maintenance_run_opts *opts)
 		strvec_push(&pack_proc.args, "--quiet");
 	else
 		strvec_push(&pack_proc.args, "--no-quiet");
-	strvec_pushf(&pack_proc.args, "%s/pack/loose", r->objects->odb->path);
+	strvec_pushf(&pack_proc.args, "%s/pack/loose", r->objects->sources->path);
 
 	pack_proc.in = -1;
 
@@ -1346,7 +1346,7 @@ static int pack_loose(struct maintenance_run_opts *opts)
 	else if (data.batch_size > 0)
 		data.batch_size--; /* Decrease for equality on limit. */
 
-	for_each_loose_file_in_objdir(r->objects->odb->path,
+	for_each_loose_file_in_objdir(r->objects->sources->path,
 				      write_loose_object_to_stdin,
 				      NULL,
 				      NULL,
@@ -1611,7 +1611,7 @@ static int maintenance_run_tasks(struct maintenance_run_opts *opts,
 	int result = 0;
 	struct lock_file lk;
 	struct repository *r = the_repository;
-	char *lock_path = xstrfmt("%s/maintenance", r->objects->odb->path);
+	char *lock_path = xstrfmt("%s/maintenance", r->objects->sources->path);
 
 	if (hold_lock_file_for_update(&lk, lock_path, LOCK_NO_DEREF) < 0) {
 		/*
@@ -3083,7 +3083,7 @@ static int update_background_schedule(const struct maintenance_start_opts *opts,
 	unsigned int i;
 	int result = 0;
 	struct lock_file lk;
-	char *lock_path = xstrfmt("%s/schedule", the_repository->objects->odb->path);
+	char *lock_path = xstrfmt("%s/schedule", the_repository->objects->sources->path);
 
 	if (hold_lock_file_for_update(&lk, lock_path, LOCK_NO_DEREF) < 0) {
 		if (errno == EEXIST)

builtin/grep.c

@@ -505,7 +505,7 @@ static int grep_submodule(struct grep_opt *opt,
 	 * lazily registered as alternates when needed (and except in an
 	 * unexpected code interaction, it won't be needed).
 	 */
-	add_submodule_odb_by_path(subrepo->objects->odb->path);
+	add_submodule_odb_by_path(subrepo->objects->sources->path);
 	obj_read_unlock();
 
 	memcpy(&subopt, opt, sizeof(subopt));

builtin/multi-pack-index.c

@@ -294,8 +294,8 @@ int cmd_multi_pack_index(int argc,
 
 	if (the_repository &&
 	    the_repository->objects &&
-	    the_repository->objects->odb)
-		opts.object_dir = xstrdup(the_repository->objects->odb->path);
+	    the_repository->objects->sources)
+		opts.object_dir = xstrdup(the_repository->objects->sources->path);
 
 	argc = parse_options(argc, argv, prefix, options,
 			     builtin_multi_pack_index_usage, 0);

builtin/submodule--helper.c

@@ -1582,7 +1582,7 @@ static const char alternate_error_advice[] = N_(
 );
 
 static int add_possible_reference_from_superproject(
-		struct object_directory *odb, void *sas_cb)
+		struct odb_source *alt_odb, void *sas_cb)
 {
 	struct submodule_alternate_setup *sas = sas_cb;
 	size_t len;
@@ -1591,12 +1591,12 @@ static int add_possible_reference_from_superproject(
 	 * If the alternate object store is another repository, try the
 	 * standard layout with .git/(modules/<name>)+/objects
 	 */
-	if (strip_suffix(odb->path, "/objects", &len)) {
+	if (strip_suffix(alt_odb->path, "/objects", &len)) {
 		struct repository alternate;
 		char *sm_alternate;
 		struct strbuf sb = STRBUF_INIT;
 		struct strbuf err = STRBUF_INIT;
-		strbuf_add(&sb, odb->path, len);
+		strbuf_add(&sb, alt_odb->path, len);
 
 		if (repo_init(&alternate, sb.buf, NULL) < 0)
 			die(_("could not get a repository handle for gitdir '%s'"),

bundle.c

@@ -233,7 +233,7 @@ int verify_bundle(struct repository *r,
 		.quiet = 1,
 	};
 
-	if (!r || !r->objects || !r->objects->odb)
+	if (!r || !r->objects || !r->objects->sources)
 		return error(_("need a repository to verify a bundle"));
 
 	for (i = 0; i < p->nr; i++) {