refs: RFC: Reftable support for git-core

index f81f085ee87..d48580a7367 100644
@@ -1043,7 +1043,7 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 	}
 
 	init_db(git_dir, real_git_dir, option_template, GIT_HASH_UNKNOWN, NULL,
-		INIT_DB_QUIET);
+		default_ref_storage(), INIT_DB_QUIET);
 
 	if (real_git_dir) {
 		free((char *)git_dir);

@@ -1199,7 +1199,8 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 		 * Now that we know what algorithm the remote side is using,
 		 * let's set ours to the same thing.
 		 */
-		initialize_repository_version(hash_algo, 1);
+		initialize_repository_version(hash_algo, 1,
+					      default_ref_storage());
 		repo_set_hash_algo(the_repository, hash_algo);
 		/*
 		 * transport_get_remote_refs() may return refs with null sha-1

109 lines not on this page · raw message

index 5897febfbec..e60b063d133 100644
@@ -207,10 +207,16 @@ static int get_stash_info(struct stash_info *info, int argc, const char **argv)
 static int do_clear_stash(void)
 {
 	struct object_id obj;
+	int result;
 	if (get_oid(ref_stash, &obj))
 		return 0;
 
-	return delete_ref(NULL, ref_stash, &obj, 0);
+	result = delete_ref(NULL, ref_stash, &obj, 0);
+
+	/* Ignore error; this is necessary for reftable, which keeps reflogs
+	 * even when refs are deleted. */
+	delete_reflog(ref_stash);
+	return result;
 }
 
 static int clear_stash(int argc, const char **argv, const char *prefix)

index 31a8a2a4e8a..75db3a2cb77 100644
@@ -14,6 +14,7 @@
 #include "utf8.h"
 #include "worktree.h"
 #include "quote.h"
+#include "../refs/refs-internal.h"
 
 static const char * const worktree_usage[] = {
 	N_("git worktree add [<options>] <path> [<commit-ish>]"),

@@ -329,9 +330,29 @@ static int add_worktree(const char *path, const char *refname,
 	 * worktree.
 	 */
 	strbuf_reset(&sb);
-	strbuf_addf(&sb, "%s/HEAD", sb_repo.buf);
-	write_file(sb.buf, "%s", oid_to_hex(null_oid()));
-	strbuf_reset(&sb);
+	if (get_main_ref_store(the_repository)->be == &refs_be_reftable) {
+		/* XXX this is cut & paste from reftable_init_db. */
+		strbuf_addf(&sb, "%s/HEAD", sb_repo.buf);
+		write_file(sb.buf, "%s", "ref: refs/heads/.invalid\n");
+		strbuf_reset(&sb);
+
+		strbuf_addf(&sb, "%s/refs", sb_repo.buf);
+		safe_create_dir(sb.buf, 1);
+		strbuf_reset(&sb);
+
+		strbuf_addf(&sb, "%s/refs/heads", sb_repo.buf);
+		write_file(sb.buf, "this repository uses the reftable format");
+		strbuf_reset(&sb);
+
+		strbuf_addf(&sb, "%s/reftable", sb_repo.buf);
+		safe_create_dir(sb.buf, 1);
+		strbuf_reset(&sb);
+	} else {
+		strbuf_addf(&sb, "%s/HEAD", sb_repo.buf);
+		write_file(sb.buf, "%s", oid_to_hex(null_oid()));
+		strbuf_reset(&sb);
+	}
+
 	strbuf_addf(&sb, "%s/commondir", sb_repo.buf);
 	write_file(sb.buf, "../..");
 

index 7cc7b29e6ec..c63d2152232 100644
@@ -653,9 +653,10 @@ int path_inside_repo(const char *prefix, const char *path);
 #define INIT_DB_EXIST_OK 0x0002
 
 int init_db(const char *git_dir, const char *real_git_dir,
-	    const char *template_dir, int hash_algo,
-	    const char *initial_branch, unsigned int flags);
-void initialize_repository_version(int hash_algo, int reinit);
+	    const char *template_dir, int hash_algo, const char *initial_branch,
+	    const char *ref_storage_format, unsigned int flags);
+void initialize_repository_version(int hash_algo, int reinit,
+				   const char *ref_storage_format);
 
 void sanitize_stdfds(void);
 int daemonize(void);

@@ -1076,6 +1077,7 @@ struct repository_format {
 	int hash_algo;
 	int sparse_index;
 	char *work_tree;
+	char *ref_storage;
 	struct string_list unknown_extensions;
 	struct string_list v1_only_extensions;
 };

index d680de3bc04..ed900148d1c 100644
@@ -20,10 +20,15 @@
 #include "repository.h"
 #include "sigchain.h"
 
+const char *default_ref_storage(void)
+{
+	return git_env_bool("GIT_TEST_REFTABLE", 0) ? "reftable" : "files";
+}
+
 /*
  * List of all available backends
  */
-static struct ref_storage_be *refs_backends = &refs_be_files;
+static struct ref_storage_be *refs_backends = &refs_be_reftable;
 
 static struct ref_storage_be *find_ref_storage_backend(const char *name)
 {

@@ -1860,13 +1865,13 @@ static struct ref_store *lookup_ref_store_map(struct hashmap *map,
  * gitdir.
  */
 static struct ref_store *ref_store_init(struct repository *repo,
-					const char *gitdir,
+					const char *gitdir, const char *be_name,
 					unsigned int flags)
 {
-	const char *be_name = "files";
-	struct ref_storage_be *be = find_ref_storage_backend(be_name);
+	struct ref_storage_be *be;
 	struct ref_store *refs;
 
+	be = find_ref_storage_backend(be_name);
 	if (!be)
 		BUG("reference backend %s is unknown", be_name);
 

@@ -1882,7 +1887,11 @@ struct ref_store *get_main_ref_store(struct repository *r)
 	if (!r->gitdir)
 		BUG("attempting to get main_ref_store outside of repository");
 
-	r->refs_private = ref_store_init(r, r->gitdir, REF_STORE_ALL_CAPS);
+	r->refs_private = ref_store_init(r, r->gitdir,
+					 r->ref_storage_format ?
+						 r->ref_storage_format :
+						 default_ref_storage(),
+					 REF_STORE_ALL_CAPS);
 	r->refs_private = maybe_debug_wrap_ref_store(r->gitdir, r->refs_private);
 	return r->refs_private;
 }

@@ -1950,7 +1959,7 @@ struct ref_store *get_submodule_ref_store(const char *submodule)
 		free(subrepo);
 		goto done;
 	}
-	refs = ref_store_init(subrepo, submodule_sb.buf,
+	refs = ref_store_init(subrepo, submodule_sb.buf, default_ref_storage(),
 			      REF_STORE_READ | REF_STORE_ODB);
 	register_ref_store_map(&submodule_ref_stores, "submodule",
 			       refs, submodule);

@@ -1964,6 +1973,7 @@ done:
 
 struct ref_store *get_worktree_ref_store(const struct worktree *wt)
 {
+	const char *format = default_ref_storage();
 	struct ref_store *refs;
 	const char *id;
 

@@ -1978,11 +1988,10 @@ struct ref_store *get_worktree_ref_store(const struct worktree *wt)
 	if (wt->id)
 		refs = ref_store_init(the_repository,
 				      git_common_path("worktrees/%s", wt->id),
-				      REF_STORE_ALL_CAPS);
+				      format, REF_STORE_ALL_CAPS);
 	else
-		refs = ref_store_init(the_repository,
-				      get_git_common_dir(),
-				      REF_STORE_ALL_CAPS);
+		refs = ref_store_init(the_repository, get_git_common_dir(),
+				      format, REF_STORE_ALL_CAPS);
 
 	if (refs)
 		register_ref_store_map(&worktree_ref_stores, "worktree",

index ff859d59513..42a35621fa6 100644
@@ -11,6 +11,9 @@ struct string_list;
 struct string_list_item;
 struct worktree;
 
+/* Returns the ref storage backend to use by default. */
+const char *default_ref_storage(void);
+
 /*
  * Resolve a reference, recursively following symbolic refererences.
  *

index 6e15db3ca4e..012820f7b41 100644
@@ -679,6 +679,7 @@ struct ref_storage_be {
 };
 
 extern struct ref_storage_be refs_be_files;
+extern struct ref_storage_be refs_be_reftable;
 extern struct ref_storage_be refs_be_packed;
 
 /*

1,898 lines not on this page · raw message

index dddee32258f..3aaae1f43cd 100644
@@ -185,6 +185,8 @@ int repo_init(struct repository *repo,
 	if (worktree)
 		repo_set_worktree(repo, worktree);
 
+	repo->ref_storage_format = xstrdup_or_null(format.ref_storage);
+
 	clear_repository_format(&format);
 	return 0;
 

index 4e46ecdca56..ceb7f55a2c7 100644
@@ -82,6 +82,9 @@ struct repository {
 	 */
 	struct ref_store *refs_private;
 
+	/* The format to use for the ref database. */
+	char *ref_storage_format;
+
 	/*
 	 * Contains path to often used file names.
 	 */

index 04ce33cdcd4..79f725eae8b 100644
@@ -563,6 +563,9 @@ static enum extension_result handle_extension(const char *var,
 				     "extensions.objectformat", value);
 		data->hash_algo = format;
 		return EXTENSION_OK;
+	} else if (!strcmp(ext, "refstorage")) {
+		data->ref_storage = xstrdup(value);
+		return EXTENSION_OK;
 	}
 	return EXTENSION_UNKNOWN;
 }

@@ -713,6 +716,7 @@ void clear_repository_format(struct repository_format *format)
 	string_list_clear(&format->v1_only_extensions, 0);
 	free(format->work_tree);
 	free(format->partial_clone);
+	free(format->ref_storage);
 	init_repository_format(format);
 }
 

@@ -1377,6 +1381,8 @@ const char *setup_git_directory_gently(int *nongit_ok)
 			the_repository->repository_format_partial_clone =
 				repo_fmt.partial_clone;
 			repo_fmt.partial_clone = NULL;
+			the_repository->ref_storage_format =
+				xstrdup_or_null(repo_fmt.ref_storage);
 		}
 	}
 	/*

@@ -1465,6 +1471,8 @@ void check_repository_format(struct repository_format *fmt)
 	repo_set_hash_algo(the_repository, fmt->hash_algo);
 	the_repository->repository_format_partial_clone =
 		xstrdup_or_null(fmt->partial_clone);
+	/* XXX why is repo->ref_storage_format set in multiple places?! */
+	the_repository->ref_storage_format = xstrdup_or_null(fmt->ref_storage);
 	clear_repository_format(&repo_fmt);
 }