git/list[1] front-page[2] threads[3] people[4] search[5] about
 

[PATCH v2 15/21] init: allow alternate backends to be set for new repos

From
David Turner <dturner@twopensource.com>
Date
Jan 12, 2016, 01:22 UTC
Message-ID
<1452561740-8668-16-git-send-email-dturner@twopensource.com>
In-Reply-To
<1452561740-8668-1-git-send-email-dturner@twopensource.com>

git init learns a new argument --ref-storage. Presently, only "files" is supported, but later we will add other backends.

When this argument is used, the repository's extensions.refStorage configuration value is set (as well as core.repositoryformatversion), and the refs backend's initdb function is used to set up the ref database.

Signed-off-by: David Turner <dturner@twopensource.com>
---
 Documentation/git-init-db.txt |  2 +-
 Documentation/git-init.txt    |  7 ++++++-
 builtin/init-db.c             | 31 ++++++++++++++++++++++++++-----
 cache.h                       |  2 ++
 path.c                        | 29 +++++++++++++++++++++++++++--
 refs.c                        |  8 ++++++++
 refs.h                        |  8 ++++++++
 setup.c                       | 12 ++++++++++++
 t/t0001-init.sh               | 24 ++++++++++++++++++++++++
 9 files changed, 114 insertions(+), 9 deletions(-)
diff --git a/Documentation/git-init-db.txt b/Documentation/git-init-db.txt
index 648a6cd..d03fb69 100644
--- a/Documentation/git-init-db.txt
+++ b/Documentation/git-init-db.txt
@@ -9,7 +9,7 @@ git-init-db - Creates an empty Git repository
 SYNOPSIS
 --------
 [verse]
-'git init-db' [-q | --quiet] [--bare] [--template=<template_directory>] [--separate-git-dir <git dir>] [--shared[=<permissions>]]
+'git init-db' [-q | --quiet] [--bare] [--template=<template_directory>] [--separate-git-dir <git dir>] [--shared[=<permissions>]] [--ref-storage=<name>]
 
 
 DESCRIPTION
diff --git a/Documentation/git-init.txt b/Documentation/git-init.txt
index 8174d27..d2b150f 100644
--- a/Documentation/git-init.txt
+++ b/Documentation/git-init.txt
@@ -12,7 +12,7 @@ SYNOPSIS
 'git init' [-q | --quiet] [--bare] [--template=<template_directory>]
 	  [--separate-git-dir <git dir>]
 	  [--shared[=<permissions>]] [directory]
-
+	  [--ref-storage=<name>]
 
 DESCRIPTION
 -----------
@@ -113,6 +113,11 @@ does not exist, it will be created.
 
 --
 
+--ref-storage=<name>::
+Type of refs storage backend. Default is to use the original "files"
+storage, which stores ref data in files in .git/refs and
+.git/packed-refs.
+
 TEMPLATE DIRECTORY
 ------------------
 
diff --git a/builtin/init-db.c b/builtin/init-db.c
index 4771e7e..ebc747c 100644
--- a/builtin/init-db.c
+++ b/builtin/init-db.c
@@ -24,6 +24,7 @@ static int init_is_bare_repository = 0;
 static int init_shared_repository = -1;
 static const char *init_db_template_dir;
 static const char *git_link;
+static char *requested_ref_storage_backend;
 
 static void copy_templates_1(struct strbuf *path, struct strbuf *template,
 			     DIR *dir)
@@ -179,6 +180,7 @@ static int create_default_files(const char *template_path)
 	int reinit;
 	int filemode;
 	struct strbuf err = STRBUF_INIT;
+	int repo_version = 0;
 
 	/* Just look for `init.templatedir` */
 	git_config(git_init_db_config, NULL);
@@ -204,9 +206,6 @@ static int create_default_files(const char *template_path)
 		adjust_shared_perm(get_git_dir());
 	}
 
-	if (refs_init_db(&err, shared_repository))
-		die("failed to set up refs db: %s", err.buf);
-
 	/*
 	 * Create the default symlink from ".git/HEAD" to the "master"
 	 * branch, if it does not exist yet.
@@ -214,14 +213,34 @@ static int create_default_files(const char *template_path)
 	path = git_path_buf(&buf, "HEAD");
 	reinit = (!access(path, R_OK)
 		  || readlink(path, junk, sizeof(junk)-1) != -1);
-	if (!reinit) {
+	if (reinit) {
+		if (requested_ref_storage_backend &&
+		    strcmp(ref_storage_backend, requested_ref_storage_backend))
+			die("You can't change the refs storage type (was %s; you requested %s)",
+			    ref_storage_backend, requested_ref_storage_backend);
+	} else {
 		if (create_symref("HEAD", "refs/heads/master", NULL) < 0)
 			exit(1);
 	}
 
+	if (requested_ref_storage_backend)
+		ref_storage_backend = requested_ref_storage_backend;
+	if (strcmp(ref_storage_backend, "files")) {
+		git_config_set("extensions.refStorage", ref_storage_backend);
+		git_config_set("core.repositoryformatversion", ref_storage_backend);
+#ifdef USE_LIBLMDB
+		register_ref_storage_backend(&refs_be_lmdb);
+#endif
+		set_ref_storage_backend(ref_storage_backend);
+		repo_version = 1;
+	}
+
+	if (refs_init_db(&err, shared_repository))
+		die("failed to set up refs db: %s", err.buf);
+
 	/* This forces creation of new config file */
 	xsnprintf(repo_version_string, sizeof(repo_version_string),
-		  "%d", GIT_REPO_VERSION);
+		  "%d", repo_version);
 	git_config_set("core.repositoryformatversion", repo_version_string);
 
 	/* Check filemode trustability */
@@ -469,6 +488,8 @@ int cmd_init_db(int argc, const char **argv, const char *prefix)
 		OPT_BIT('q', "quiet", &flags, N_("be quiet"), INIT_DB_QUIET),
 		OPT_STRING(0, "separate-git-dir", &real_git_dir, N_("gitdir"),
 			   N_("separate git dir from working tree")),
+		OPT_STRING(0, "ref-storage", &requested_ref_storage_backend,
+			   N_("name"), N_("name of backend type to use")),
 		OPT_END()
 	};
 
diff --git a/cache.h b/cache.h
index 51c35c3..d5297f2 100644
--- a/cache.h
+++ b/cache.h
@@ -696,6 +696,8 @@ extern enum object_creation_mode object_creation_mode;
 
 extern char *notes_ref_name;
 
+extern const char *ref_storage_backend;
+
 extern int grafts_replace_parents;
 
 /*
diff --git a/path.c b/path.c
index 3cd155e..be01cdd 100644
--- a/path.c
+++ b/path.c
@@ -2,6 +2,7 @@
  * Utilities for paths and pathnames
  */
 #include "cache.h"
+#include "refs.h"
 #include "strbuf.h"
 #include "string-list.h"
 #include "dir.h"
@@ -511,8 +512,32 @@ int validate_headref(const char *path)
 	int fd;
 	ssize_t len;
 
-	if (lstat(path, &st) < 0)
-		return -1;
+	if (lstat(path, &st) < 0) {
+		int backend_type_set;
+		struct strbuf config_path = STRBUF_INIT;
+		char *pathdup = xstrdup(path);
+		char *git_dir = dirname(pathdup);
+		char *storage = NULL;
+
+		strbuf_addf(&config_path, "%s/%s", git_dir, "config");
+		free(pathdup);
+
+		if (git_config_from_file(ref_storage_backend_config,
+					 config_path.buf, &storage)) {
+			strbuf_release(&config_path);
+			return -1;
+		}
+
+		backend_type_set = !!storage;
+		free((void *)storage);
+		strbuf_release(&config_path);
+		/*
+		 * Alternate backends are assumed to keep HEAD
+		 * in a valid state, so there's no need to do
+		 * further validation.
+		 */
+		return backend_type_set ? 0 : -1;
+	}
 
 	/* Make sure it is a "refs/.." symlink */
 	if (S_ISLNK(st.st_mode)) {
diff --git a/refs.c b/refs.c
index d035feb..07f1dab 100644
--- a/refs.c
+++ b/refs.c
@@ -24,6 +24,14 @@ static struct ref_storage_be *the_refs_backend = &refs_be_files;
  */
 static struct ref_storage_be *refs_backends = &refs_be_files;
 
+const char *ref_storage_backend = "files";
+
+void register_ref_storage_backend(struct ref_storage_be *be)
+{
+	be->next = refs_backends;
+	refs_backends = be;
+}
+
 int set_ref_storage_backend(const char *name)
 {
 	struct ref_storage_be *be;
diff --git a/refs.h b/refs.h
index df7bfc4..7a27c94 100644
--- a/refs.h
+++ b/refs.h
@@ -511,8 +511,16 @@ extern int reflog_expire(const char *refname, const unsigned char *sha1,
 			 void *policy_cb_data);
 
 /*
+ * Read the refdb storage backend name out of the config file
+ */
+int ref_storage_backend_config(const char *var, const char *value, void *ptr);
+
+struct ref_storage_be;
+/*
  * Switch to an alternate ref storage backend.
  */
 int set_ref_storage_backend(const char *name);
 
+void register_ref_storage_backend(struct ref_storage_be *be);
+
 #endif /* REFS_H */
diff --git a/setup.c b/setup.c
index d343725..a329a51 100644
--- a/setup.c
+++ b/setup.c
@@ -1,5 +1,6 @@
 #include "cache.h"
 #include "dir.h"
+#include "refs.h"
 #include "string-list.h"
 
 static int inside_git_dir = -1;
@@ -263,6 +264,15 @@ int get_common_dir_noenv(struct strbuf *sb, const char *gitdir)
 	return ret;
 }
 
+int ref_storage_backend_config(const char *var, const char *value, void *ptr)
+{
+	char **cdata = ptr;
+
+	if (!strcmp(var, "extensions.refstorage"))
+		*cdata = xstrdup(value);
+	return 0;
+}
+
 /*
  * Test if it looks like we're at a git directory.
  * We want to see:
@@ -373,6 +383,8 @@ static int check_repo_format(const char *var, const char *value, void *cb)
 			;
 		else if (!strcmp(ext, "preciousobjects"))
 			repository_format_precious_objects = git_config_bool(var, value);
+		else if (!strcmp(ext, "refstorage"))
+			ref_storage_backend = xstrdup(value);
 		else
 			string_list_append(&unknown_extensions, ext);
 	}
diff --git a/t/t0001-init.sh b/t/t0001-init.sh
index f91bbcf..7f754a3 100755
--- a/t/t0001-init.sh
+++ b/t/t0001-init.sh
@@ -157,6 +157,30 @@ test_expect_success 'reinit' '
 	test_i18ncmp again/empty again/err2
 '
 
+test_expect_success 'init with bogus storage backend fails' '
+
+	(
+		mkdir again2 &&
+		cd again2 &&
+		git init --ref-storage=test >out2 2>err2
+	)
+'
+
+test_expect_failure 'reinit with changed storage backend fails' '
+
+	(
+		mkdir again3 &&
+		cd again3 &&
+		git init >out1 2>err1 &&
+		git init --ref-storage=test >out2 2>err2
+	) &&
+	test_i18ngrep "Initialized empty" again3/out1 &&
+	test_i18ngrep "Reinitialized existing" again3/out2 &&
+	>again3/empty &&
+	test_i18ncmp again3/empty again3/err1 &&
+	test_i18ncmp again3/empty again3/err2
+'
+
 test_expect_success 'init with --template' '
 	mkdir template-source &&
 	echo content >template-source/file &&

-- 
2.4.2.749.g730654d-twtrsrc
Previous: David TurnerNext: David Turner
Message 20 of 35 in “refs backend reroll”
  1. 00/21 refs backend rerollDavid Turner, Jan 12, 2016
  2. 01/21 refs: add a backend method structure with transaction functionsDavid Turner, Jan 12, 2016
  3. 02/21 refs: add methods for misc ref operationsDavid Turner, Jan 12, 2016
  4. 03/21 refs: add methods for the ref iteratorsDavid Turner, Jan 12, 2016
  5. 04/21 refs: add do_for_each_per_worktree_refDavid Turner, Jan 12, 2016
  6. 05/21 refs: add methods for reflogDavid Turner, Jan 12, 2016
  7. 06/21 refs: add method for initial ref transaction commitDavid Turner, Jan 12, 2016
  8. 07/21 refs: add method for delete_refsDavid Turner, Jan 12, 2016
  9. 08/21 refs: add methods to init refs dbDavid Turner, Jan 12, 2016
  10. 09/21 refs: add method to rename refsDavid Turner, Jan 12, 2016
  11. 10/21 refs: make lock genericDavid Turner, Jan 12, 2016
  12. 11/21 refs: move duplicate check to common codeDavid Turner, Jan 12, 2016
  13. 12/21 refs: allow log-only updatesDavid Turner, Jan 12, 2016
  14. 13/21 refs: resolve symbolic refs firstDavid Turner, Jan 12, 2016
  15. Junio C HamanoJan 13, 2016
  16. David TurnerJan 13, 2016
  17. 14/21 refs: always handle non-normal refs in files backendDavid Turner, Jan 12, 2016
  18. Junio C HamanoJan 13, 2016
  19. David TurnerJan 13, 2016
  20. 15/21 init: allow alternate backends to be set for new reposDavid Turner, Jan 12, 2016
  21. 16/21 refs: check submodules ref storage configDavid Turner, Jan 12, 2016
  22. Junio C HamanoJan 13, 2016
  23. David TurnerJan 13, 2016
  24. Junio C HamanoJan 13, 2016
  25. 17/21 clone: use child_process for recursive checkoutsDavid Turner, Jan 12, 2016
  26. 18/21 refs: allow ref backend to be set for cloneDavid Turner, Jan 12, 2016
  27. 19/21 svn: learn ref-storage argumentDavid Turner, Jan 12, 2016
  28. 20/21 refs: add LMDB refs backendDavid Turner, Jan 12, 2016
  29. Jeff KingJan 14, 2016
  30. David TurnerJan 14, 2016
  31. 21/21 refs: tests for lmdb backendDavid Turner, Jan 12, 2016
  32. Junio C HamanoJan 13, 2016
  33. Jeff KingJan 14, 2016
  34. David TurnerJan 14, 2016
  35. Jeff KingJan 14, 2016

Read the whole thread, see it on lore, or plain text.

$ cat FOOTERMessages come from the public archive at lore.kernel.org/git, fetched every hour. The front page is chosen and written each morning by an AI editor and can be wrong; the threads themselves are the record. About and API. For agents: an MCP server at https://gitlist.dev/mcp, and any thread, story or person page as Markdown by adding .md to its URL (or sending Accept: text/markdown). Details in /llms.txt.