gc.c: extend vfs-cache-move to migrate loose objs

Extend the `vfs-cache-move` maintenance task to also migrate any loose
objects in the local ODB directory to the shared volume cache for VFS
for Git/Scalar (if set).

Signed-off-by: Matthew John Cheetham <mjcheetham@outlook.com>

Author: mjcheetham

Documentation/git-maintenance.txt

@@ -163,8 +163,8 @@ vfs-cache-move::
 	The `vfs-cache-move` task only operates on Scalar or VFS for Git
 	repositories (cloned with either `scalar clone` or `gvfs clone`) that
 	have the `gvfs.sharedCache` configuration setting present. This task
-	migrates pack files from the repository's object directory in to the
-	shared volume cache.
+	migrates pack files and loose objects from the repository's object
+	directory in to the shared volume cache.
 
 OPTIONS
 -------

builtin/gc.c

@@ -1475,16 +1475,34 @@ static void move_pack_to_vfs_cache(const char *full_path, size_t full_path_len,
 
 	srcdir = xstrndup(full_path, full_path_len - strlen(file_name) - 1);
 
-	/* Same source + destination means there's no work to do. */
-	if (!fspathcmp(srcdir, vfs_object_dir))
-		goto cleanup;
-
 	migrate_pack(srcdir, dstdir, file_name);
 
-cleanup:
 	free(srcdir);
 }
 
+static int move_loose_object_to_vfs_cache(const struct object_id *oid,
+					  const char *path,
+					  UNUSED void *data)
+{
+	struct stat st;
+	struct strbuf dst = STRBUF_INIT;
+	char *hex = oid_to_hex(oid);
+
+	strbuf_addf(&dst, "%s/%.2s/", vfs_object_dir, hex);
+
+	if (stat(dst.buf, &st)) {
+		if (mkdir(dst.buf, 0777))
+			die_errno(_("failed to create directory '%s'"), dst.buf);
+	} else if (!S_ISDIR(st.st_mode))
+		die(_("expected '%s' to be a directory"), dst.buf);
+
+	strbuf_addstr(&dst, hex+2);
+	rename_or_copy_or_die(path, dst.buf);
+
+	strbuf_release(&dst);
+	return 0;
+}
+
 static int maintenance_task_vfs_cache_move(UNUSED struct maintenance_run_opts *opts,
 					   UNUSED struct gc_config *cfg)
 {
@@ -1495,11 +1513,19 @@ static int maintenance_task_vfs_cache_move(UNUSED struct maintenance_run_opts *o
 	if (!vfs_object_dir)
 		return 0;
 
+	/* If the dest is the same as the local odb path then we do nothing. */
+	if (!fspathcmp(r->objects->odb->path, vfs_object_dir))
+		goto cleanup;
+
 	strbuf_addf(&dstdir, "%s/pack", vfs_object_dir);
 
 	for_each_file_in_pack_dir(r->objects->odb->path, move_pack_to_vfs_cache,
 				  dstdir.buf);
 
+	for_each_loose_object(move_loose_object_to_vfs_cache, NULL,
+			      FOR_EACH_OBJECT_LOCAL_ONLY);
+
+cleanup:
 	strbuf_release(&dstdir);
 	return 0;
 }

t/t7900-maintenance.sh

@@ -47,6 +47,10 @@ test_get_packdir_files() {
 	fi
 }
 
+test_get_loose_object_files () {
+	find .git/objects -type f -path '.git/objects/??/*'
+}
+
 test_expect_success 'help text' '
 	test_expect_code 129 git maintenance -h >actual &&
 	test_grep "usage: git maintenance <subcommand>" actual &&
@@ -1041,6 +1045,7 @@ test_expect_success 'vfs-cache-move task with no shared cache no op' '
 		test_import_packfile &&
 		test_get_packdir_files "*.pack" "*.idx" "*.keep" "*.rev" \
 			>files.txt &&
+		test_get_loose_object_files >>files.txt &&
 
 		git maintenance run &&
 		while IFS= read -r f; do
@@ -1049,21 +1054,22 @@ test_expect_success 'vfs-cache-move task with no shared cache no op' '
 	)
 '
 
-test_expect_success 'vfs-cache-move task cache path same as pack dir no op' '
+test_expect_success 'vfs-cache-move task cache path same as local odb no op' '
 	test_when_finished "rm -rf repo" &&
 	git init repo &&
 	(
 		cd repo &&
 
 		test_commit something &&
-		git config set gvfs.sharedcache .git/objects/pack &&
+		git config set gvfs.sharedcache .git/objects &&
 		git config set maintenance.gc.enabled false &&
 		git config set maintenance.vfs-cache-move.enabled true &&
 		git config set maintenance.vfs-cache-move.auto 1 &&
 
 		test_import_packfile &&
 		test_get_packdir_files "*.pack" "*.idx" "*.keep" "*.rev" \
 			>files.txt &&
+		test_get_loose_object_files >>files.txt &&
 
 		git maintenance run &&
 		while IFS= read -r f; do
@@ -1087,10 +1093,11 @@ test_expect_success 'vfs-cache-move task no .rev or .keep' '
 
 		test_import_packfile &&
 		test_get_packdir_files "*.pack" "*.idx" >src.txt &&
+		test_get_loose_object_files >>src.txt &&
 
 		rm -f .git/objects/pack/*.rev .git/objects/pack/*.keep &&
 
-		sed "s/.*\\//..\\/cache\\/pack\\//" src.txt >dst.txt &&
+		sed "s/.git\\/objects\\//..\\/cache\\//" src.txt >dst.txt &&
 
 		git maintenance run &&
 		while IFS= read -r f; do
@@ -1119,8 +1126,9 @@ test_expect_success 'vfs-cache-move task success' '
 		test_import_packfile &&
 		test_get_packdir_files "*.pack" "*.idx" "*.keep" "*.rev" \
 			>src.txt &&
+		test_get_loose_object_files >>src.txt &&
 
-		sed "s/.*\\//..\\/cache\\/pack\\//" src.txt >dst.txt &&
+		sed "s/.git\\/objects\\//..\\/cache\\//" src.txt >dst.txt &&
 
 		git maintenance run &&
 		while IFS= read -r f; do