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 <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 47 insertions, 47 deletions

diff --git a/commit-graph.c b/commit-graph.c
index 905fcbdf0e..12d32cdad1 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -37,7 +37,7 @@ void git_test_write_commit_graph_or_die(void)
 	if (git_env_bool(GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS, 0))
 		flags = COMMIT_GRAPH_WRITE_BLOOM_FILTERS;
 
-	if (write_commit_graph_reachable(the_repository->objects->odb,
+	if (write_commit_graph_reachable(the_repository->objects->sources,
 					 flags, NULL))
 		die("failed to write commit-graph under GIT_TEST_COMMIT_GRAPH");
 }
@@ -191,21 +191,21 @@ static int commit_gen_cmp(const void *va, const void *vb)
 	return 0;
 }
 
-char *get_commit_graph_filename(struct object_directory *obj_dir)
+char *get_commit_graph_filename(struct odb_source *source)
 {
-	return xstrfmt("%s/info/commit-graph", obj_dir->path);
+	return xstrfmt("%s/info/commit-graph", source->path);
 }
 
-static char *get_split_graph_filename(struct object_directory *odb,
+static char *get_split_graph_filename(struct odb_source *source,
 				      const char *oid_hex)
 {
-	return xstrfmt("%s/info/commit-graphs/graph-%s.graph", odb->path,
+	return xstrfmt("%s/info/commit-graphs/graph-%s.graph", source->path,
 		       oid_hex);
 }
 
-char *get_commit_graph_chain_filename(struct object_directory *odb)
+char *get_commit_graph_chain_filename(struct odb_source *source)
 {
-	return xstrfmt("%s/info/commit-graphs/commit-graph-chain", odb->path);
+	return xstrfmt("%s/info/commit-graphs/commit-graph-chain", source->path);
 }
 
 static struct commit_graph *alloc_commit_graph(void)
@@ -250,7 +250,7 @@ int open_commit_graph(const char *graph_file, int *fd, struct stat *st)
 
 struct commit_graph *load_commit_graph_one_fd_st(struct repository *r,
 						 int fd, struct stat *st,
-						 struct object_directory *odb)
+						 struct odb_source *source)
 {
 	void *graph_map;
 	size_t graph_size;
@@ -269,7 +269,7 @@ struct commit_graph *load_commit_graph_one_fd_st(struct repository *r,
 	ret = parse_commit_graph(&r->settings, graph_map, graph_size);
 
 	if (ret)
-		ret->odb = odb;
+		ret->odb_source = source;
 	else
 		munmap(graph_map, graph_size);
 
@@ -487,7 +487,7 @@ free_and_return:
 
 static struct commit_graph *load_commit_graph_one(struct repository *r,
 						  const char *graph_file,
-						  struct object_directory *odb)
+						  struct odb_source *source)
 {
 
 	struct stat st;
@@ -498,7 +498,7 @@ static struct commit_graph *load_commit_graph_one(struct repository *r,
 	if (!open_ok)
 		return NULL;
 
-	g = load_commit_graph_one_fd_st(r, fd, &st, odb);
+	g = load_commit_graph_one_fd_st(r, fd, &st, source);
 
 	if (g)
 		g->filename = xstrdup(graph_file);
@@ -507,10 +507,10 @@ static struct commit_graph *load_commit_graph_one(struct repository *r,
 }
 
 static struct commit_graph *load_commit_graph_v1(struct repository *r,
-						 struct object_directory *odb)
+						 struct odb_source *source)
 {
-	char *graph_name = get_commit_graph_filename(odb);
-	struct commit_graph *g = load_commit_graph_one(r, graph_name, odb);
+	char *graph_name = get_commit_graph_filename(source);
+	struct commit_graph *g = load_commit_graph_one(r, graph_name, source);
 	free(graph_name);
 
 	return g;
@@ -652,7 +652,7 @@ struct commit_graph *load_commit_graph_chain_fd_st(struct repository *r,
 	prepare_alt_odb(r);
 
 	for (i = 0; i < count; i++) {
-		struct object_directory *odb;
+		struct odb_source *source;
 
 		if (strbuf_getline_lf(&line, fp) == EOF)
 			break;
@@ -665,9 +665,9 @@ struct commit_graph *load_commit_graph_chain_fd_st(struct repository *r,
 		}
 
 		valid = 0;
-		for (odb = r->objects->odb; odb; odb = odb->next) {
-			char *graph_name = get_split_graph_filename(odb, line.buf);
-			struct commit_graph *g = load_commit_graph_one(r, graph_name, odb);
+		for (source = r->objects->sources; source; source = source->next) {
+			char *graph_name = get_split_graph_filename(source, line.buf);
+			struct commit_graph *g = load_commit_graph_one(r, graph_name, source);
 
 			free(graph_name);
 
@@ -701,9 +701,9 @@ struct commit_graph *load_commit_graph_chain_fd_st(struct repository *r,
 }
 
 static struct commit_graph *load_commit_graph_chain(struct repository *r,
-						    struct object_directory *odb)
+						    struct odb_source *source)
 {
-	char *chain_file = get_commit_graph_chain_filename(odb);
+	char *chain_file = get_commit_graph_chain_filename(source);
 	struct stat st;
 	int fd;
 	struct commit_graph *g = NULL;
@@ -719,24 +719,24 @@ static struct commit_graph *load_commit_graph_chain(struct repository *r,
 }
 
 struct commit_graph *read_commit_graph_one(struct repository *r,
-					   struct object_directory *odb)
+					   struct odb_source *source)
 {
-	struct commit_graph *g = load_commit_graph_v1(r, odb);
+	struct commit_graph *g = load_commit_graph_v1(r, source);
 
 	if (!g)
-		g = load_commit_graph_chain(r, odb);
+		g = load_commit_graph_chain(r, source);
 
 	return g;
 }
 
 static void prepare_commit_graph_one(struct repository *r,
-				     struct object_directory *odb)
+				     struct odb_source *source)
 {
 
 	if (r->objects->commit_graph)
 		return;
 
-	r->objects->commit_graph = read_commit_graph_one(r, odb);
+	r->objects->commit_graph = read_commit_graph_one(r, source);
 }
 
 /*
@@ -747,7 +747,7 @@ static void prepare_commit_graph_one(struct repository *r,
  */
 static int prepare_commit_graph(struct repository *r)
 {
-	struct object_directory *odb;
+	struct odb_source *source;
 
 	/*
 	 * Early return if there is no git dir or if the commit graph is
@@ -779,10 +779,10 @@ static int prepare_commit_graph(struct repository *r)
 		return 0;
 
 	prepare_alt_odb(r);
-	for (odb = r->objects->odb;
-	     !r->objects->commit_graph && odb;
-	     odb = odb->next)
-		prepare_commit_graph_one(r, odb);
+	for (source = r->objects->sources;
+	     !r->objects->commit_graph && source;
+	     source = source->next)
+		prepare_commit_graph_one(r, source);
 	return !!r->objects->commit_graph;
 }
 
@@ -1137,7 +1137,7 @@ struct packed_commit_list {
 
 struct write_commit_graph_context {
 	struct repository *r;
-	struct object_directory *odb;
+	struct odb_source *odb_source;
 	char *graph_name;
 	struct oid_array oids;
 	struct packed_commit_list commits;
@@ -1870,7 +1870,7 @@ static int add_ref_to_set(const char *refname UNUSED,
 	return 0;
 }
 
-int write_commit_graph_reachable(struct object_directory *odb,
+int write_commit_graph_reachable(struct odb_source *source,
 				 enum commit_graph_write_flags flags,
 				 const struct commit_graph_opts *opts)
 {
@@ -1890,7 +1890,7 @@ int write_commit_graph_reachable(struct object_directory *odb,
 
 	stop_progress(&data.progress);
 
-	result = write_commit_graph(odb, NULL, &commits,
+	result = write_commit_graph(source, NULL, &commits,
 				    flags, opts);
 
 	oidset_clear(&commits);
@@ -1906,7 +1906,7 @@ static int fill_oids_from_packs(struct write_commit_graph_context *ctx,
 	int dirlen;
 	int ret = 0;
 
-	strbuf_addf(&packname, "%s/pack/", ctx->odb->path);
+	strbuf_addf(&packname, "%s/pack/", ctx->odb_source->path);
 	dirlen = packname.len;
 	if (ctx->report_progress) {
 		strbuf_addf(&progress_title,
@@ -2060,10 +2060,10 @@ static int write_commit_graph_file(struct write_commit_graph_context *ctx)
 
 		strbuf_addf(&tmp_file,
 			    "%s/info/commit-graphs/tmp_graph_XXXXXX",
-			    ctx->odb->path);
+			    ctx->odb_source->path);
 		ctx->graph_name = strbuf_detach(&tmp_file, NULL);
 	} else {
-		ctx->graph_name = get_commit_graph_filename(ctx->odb);
+		ctx->graph_name = get_commit_graph_filename(ctx->odb_source);
 	}
 
 	if (safe_create_leading_directories(the_repository, ctx->graph_name)) {
@@ -2073,7 +2073,7 @@ static int write_commit_graph_file(struct write_commit_graph_context *ctx)
 	}
 
 	if (ctx->split) {
-		char *lock_name = get_commit_graph_chain_filename(ctx->odb);
+		char *lock_name = get_commit_graph_chain_filename(ctx->odb_source);
 
 		hold_lock_file_for_update_mode(&lk, lock_name,
 					       LOCK_DIE_ON_ERROR, 0444);
@@ -2161,7 +2161,7 @@ static int write_commit_graph_file(struct write_commit_graph_context *ctx)
 
 	if (ctx->split && ctx->base_graph_name && ctx->num_commit_graphs_after > 1) {
 		char *new_base_hash = xstrdup(oid_to_hex(&ctx->new_base_graph->oid));
-		char *new_base_name = get_split_graph_filename(ctx->new_base_graph->odb, new_base_hash);
+		char *new_base_name = get_split_graph_filename(ctx->new_base_graph->odb_source, new_base_hash);
 
 		free(ctx->commit_graph_filenames_after[ctx->num_commit_graphs_after - 2]);
 		free(ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 2]);
@@ -2201,14 +2201,14 @@ static int write_commit_graph_file(struct write_commit_graph_context *ctx)
 				}
 			}
 		} else {
-			char *graph_name = get_commit_graph_filename(ctx->odb);
+			char *graph_name = get_commit_graph_filename(ctx->odb_source);
 			unlink(graph_name);
 			free(graph_name);
 		}
 
 		free(ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 1]);
 		ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 1] = xstrdup(hash_to_hex(file_hash));
-		final_graph_name = get_split_graph_filename(ctx->odb,
+		final_graph_name = get_split_graph_filename(ctx->odb_source,
 					ctx->commit_graph_hash_after[ctx->num_commit_graphs_after - 1]);
 		free(ctx->commit_graph_filenames_after[ctx->num_commit_graphs_after - 1]);
 		ctx->commit_graph_filenames_after[ctx->num_commit_graphs_after - 1] = final_graph_name;
@@ -2259,7 +2259,7 @@ static void split_graph_merge_strategy(struct write_commit_graph_context *ctx)
 	    flags != COMMIT_GRAPH_SPLIT_REPLACE) {
 		while (g && (g->num_commits <= st_mult(size_mult, num_commits) ||
 			    (max_commits && num_commits > max_commits))) {
-			if (g->odb != ctx->odb)
+			if (g->odb_source != ctx->odb_source)
 				break;
 
 			if (unsigned_add_overflows(num_commits, g->num_commits))
@@ -2281,10 +2281,10 @@ static void split_graph_merge_strategy(struct write_commit_graph_context *ctx)
 		    "should be 1 with --split=replace");
 
 	if (ctx->num_commit_graphs_after == 2) {
-		char *old_graph_name = get_commit_graph_filename(g->odb);
+		char *old_graph_name = get_commit_graph_filename(g->odb_source);
 
 		if (!strcmp(g->filename, old_graph_name) &&
-		    g->odb != ctx->odb) {
+		    g->odb_source != ctx->odb_source) {
 			ctx->num_commit_graphs_after = 1;
 			ctx->new_base_graph = NULL;
 		}
@@ -2456,13 +2456,13 @@ static void expire_commit_graphs(struct write_commit_graph_context *ctx)
 	if (ctx->opts && ctx->opts->expire_time)
 		expire_time = ctx->opts->expire_time;
 	if (!ctx->split) {
-		char *chain_file_name = get_commit_graph_chain_filename(ctx->odb);
+		char *chain_file_name = get_commit_graph_chain_filename(ctx->odb_source);
 		unlink(chain_file_name);
 		free(chain_file_name);
 		ctx->num_commit_graphs_after = 0;
 	}
 
-	strbuf_addstr(&path, ctx->odb->path);
+	strbuf_addstr(&path, ctx->odb_source->path);
 	strbuf_addstr(&path, "/info/commit-graphs");
 	dir = opendir(path.buf);
 
@@ -2504,7 +2504,7 @@ out:
 	strbuf_release(&path);
 }
 
-int write_commit_graph(struct object_directory *odb,
+int write_commit_graph(struct odb_source *source,
 		       const struct string_list *const pack_indexes,
 		       struct oidset *commits,
 		       enum commit_graph_write_flags flags,
@@ -2513,7 +2513,7 @@ int write_commit_graph(struct object_directory *odb,
 	struct repository *r = the_repository;
 	struct write_commit_graph_context ctx = {
 		.r = r,
-		.odb = odb,
+		.odb_source = source,
 		.append = flags & COMMIT_GRAPH_WRITE_APPEND ? 1 : 0,
 		.report_progress = flags & COMMIT_GRAPH_WRITE_PROGRESS ? 1 : 0,
 		.split = flags & COMMIT_GRAPH_WRITE_SPLIT ? 1 : 0,