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[PATCH v6 23/32] init: allow alternate ref strorage to be set for new repos

From
David Turner <dturner@twopensource.com>
Date
Feb 24, 2016, 22:58 UTC
Message-ID
<1456354744-8022-24-git-send-email-dturner@twopensource.com>
In-Reply-To
<1456354744-8022-1-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 storage backends.

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

Signed-off-by: David Turner <dturner@twopensource.com>
Signed-off-by: SZEDER Gábor <szeder@ira.uka.de>
---
 Documentation/git-init-db.txt          |  2 +-
 Documentation/git-init.txt             |  7 +++++-
 builtin/init-db.c                      | 44 +++++++++++++++++++++++++++-------
 cache.h                                |  2 ++
 contrib/completion/git-completion.bash |  3 ++-
 path.c                                 | 29 ++++++++++++++++++++--
 refs.c                                 |  2 ++
 refs.h                                 |  5 ++++
 setup.c                                | 12 ++++++++++
 t/t0001-init.sh                        | 25 +++++++++++++++++++
 10 files changed, 118 insertions(+), 13 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..93f8d0c 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 `$GIT_DIR/refs` and
+`$GIT_DIR/packed-refs`.
+
 TEMPLATE DIRECTORY
 ------------------
 
diff --git a/builtin/init-db.c b/builtin/init-db.c
index 0c8f4ac..753cb1c 100644
--- a/builtin/init-db.c
+++ b/builtin/init-db.c
@@ -23,6 +23,7 @@ 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)
@@ -178,6 +179,7 @@ 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);
@@ -204,6 +206,32 @@ static int create_default_files(const char *template_path)
 	}
 
 	/*
+	 * Create the default symref from ".git/HEAD" to the "master"
+	 * branch, if it does not exist yet.
+	 */
+	path = git_path_buf(&buf, "HEAD");
+	reinit = (!access(path, R_OK)
+		  || readlink(path, junk, sizeof(junk)-1) != -1);
+	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);
+	}
+
+	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);
+		if (set_ref_storage_backend(ref_storage_backend))
+			die(_("Unknown ref storage backend %s"),
+			    ref_storage_backend);
+		repo_version = 1;
+	}
+
+	/*
 	 * We need to create a "refs" dir in any case so that older
 	 * versions of git can tell that this is a repository.
 	 */
@@ -212,13 +240,6 @@ static int create_default_files(const char *template_path)
 	if (refs_init_db(shared_repository, &err))
 		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.
-	 */
-	path = git_path_buf(&buf, "HEAD");
-	reinit = (!access(path, R_OK)
-		  || readlink(path, junk, sizeof(junk)-1) != -1);
 	if (!reinit) {
 		if (create_symref("HEAD", "refs/heads/master", NULL) < 0)
 			exit(1);
@@ -226,7 +247,7 @@ static int create_default_files(const char *template_path)
 
 	/* 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 */
@@ -474,11 +495,18 @@ 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()
 	};
 
 	argc = parse_options(argc, argv, prefix, init_db_options, init_db_usage, 0);
 
+	if (requested_ref_storage_backend &&
+	    !ref_storage_backend_exists(requested_ref_storage_backend))
+		die(_("Unknown ref storage backend %s"),
+		    requested_ref_storage_backend);
+
 	if (real_git_dir && !is_absolute_path(real_git_dir))
 		real_git_dir = xstrdup(real_path(real_git_dir));
 
diff --git a/cache.h b/cache.h
index 4307174..a54c97b 100644
--- a/cache.h
+++ b/cache.h
@@ -734,6 +734,8 @@ 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/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index 45ec47f..0138d03 100644
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@ -1362,7 +1362,8 @@ _git_init ()
 		return
 		;;
 	--*)
-		__gitcomp "--quiet --bare --template= --shared --shared="
+		__gitcomp "--quiet --bare --template= --shared --shared=
+			--ref-storage="
 		return
 		;;
 	esac
diff --git a/path.c b/path.c
index 8b7e168..2e67a2b 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 b2acf0e..04d8f0c 100644
--- a/refs.c
+++ b/refs.c
@@ -23,6 +23,8 @@ 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";
+
 int set_ref_storage_backend(const char *name)
 {
 	struct ref_storage_be *be;
diff --git a/refs.h b/refs.h
index feff82e..f08e886 100644
--- a/refs.h
+++ b/refs.h
@@ -511,6 +511,11 @@ 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);
+
+/*
  * Switch to an alternate ref storage backend.
  */
 int set_ref_storage_backend(const char *name);
diff --git a/setup.c b/setup.c
index 0deb022..1a62277 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:
@@ -390,6 +400,8 @@ 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 295aa59..31c8279 100755
--- a/t/t0001-init.sh
+++ b/t/t0001-init.sh
@@ -174,6 +174,31 @@ test_expect_success 'reinit' '
 	test_i18ncmp again/empty again/err2
 '
 
+test_expect_success 'init with bogus storage backend fails' '
+
+	(
+		mkdir again2 &&
+		cd again2 &&
+		test_must_fail git init --ref-storage=test >out2 2>err2 &&
+		test_i18ngrep "Unknown ref storage backend test" 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 &&

-- 
2.4.2.767.g62658d5-twtrsrc
Previous: David TurnerNext: David Turner
Message 31 of 56 in “refs backend”
  1. 00/32 refs backendDavid Turner, Feb 24, 2016
  2. 01/32 refs: move head_ref{,_submodule} to the common codeDavid Turner, Feb 24, 2016
  3. 02/32 refs: move for_each_*ref* functions into common codeDavid Turner, Feb 24, 2016
  4. 03/32 files-backend: break out ref readingDavid Turner, Feb 24, 2016
  5. Junio C HamanoFeb 25, 2016
  6. Junio C HamanoFeb 25, 2016
  7. David TurnerFeb 25, 2016
  8. Junio C HamanoFeb 25, 2016
  9. 04/32 refs: move resolve_ref_unsafe into common codeDavid Turner, Feb 24, 2016
  10. Junio C HamanoFeb 25, 2016
  11. 05/32 refs: add a backend method structure with transaction functionsDavid Turner, Feb 24, 2016
  12. Jeff KingFeb 27, 2016
  13. David TurnerFeb 29, 2016
  14. 06/32 refs: add methods for misc ref operationsDavid Turner, Feb 24, 2016
  15. 07/32 refs: add method for do_for_each_refDavid Turner, Feb 24, 2016
  16. 08/32 refs: reduce the visibility of do_for_each_ref()David Turner, Feb 24, 2016
  17. 09/32 refs: add do_for_each_per_worktree_refDavid Turner, Feb 24, 2016
  18. 10/32 refs: add methods for reflogDavid Turner, Feb 24, 2016
  19. 11/32 refs: add method for initial ref transaction commitDavid Turner, Feb 24, 2016
  20. 12/32 refs: add method for delete_refsDavid Turner, Feb 24, 2016
  21. 13/32 refs: add methods to init refs dbDavid Turner, Feb 24, 2016
  22. 14/32 refs: add method to rename refsDavid Turner, Feb 24, 2016
  23. 15/32 refs: handle non-normal ref renamesDavid Turner, Feb 24, 2016
  24. 16/32 refs: make lock genericDavid Turner, Feb 24, 2016
  25. 17/32 refs: move duplicate check to common codeDavid Turner, Feb 24, 2016
  26. 18/32 refs: allow log-only updatesDavid Turner, Feb 24, 2016
  27. 19/32 refs: don't dereference on renameDavid Turner, Feb 24, 2016
  28. 20/32 refs: on symref reflog expire, lock symref not referrentDavid Turner, Feb 24, 2016
  29. 21/32 refs: resolve symbolic refs firstDavid Turner, Feb 24, 2016
  30. 22/32 refs: always handle non-normal refs in files backendDavid Turner, Feb 24, 2016
  31. 23/32 init: allow alternate ref strorage to be set for new reposDavid Turner, Feb 24, 2016
  32. 24/32 refs: check submodules' ref storage configDavid Turner, Feb 24, 2016
  33. 25/32 clone: allow ref storage backend to be set for cloneDavid Turner, Feb 24, 2016
  34. 26/32 svn: learn ref-storage argumentDavid Turner, Feb 24, 2016
  35. 27/32 refs: register ref storage backendsDavid Turner, Feb 24, 2016
  36. 28/32 config: read ref storage config on startupDavid Turner, Feb 24, 2016
  37. Jeff KingFeb 27, 2016
  38. Jeff KingFeb 27, 2016
  39. David TurnerFeb 29, 2016
  40. Jeff KingFeb 29, 2016
  41. David TurnerFeb 29, 2016
  42. Jeff KingFeb 29, 2016
  43. Jeff KingFeb 29, 2016
  44. David TurnerFeb 29, 2016
  45. 29/32 refs: break out resolve_ref_unsafe_submoduleDavid Turner, Feb 24, 2016
  46. 30/32 refs: add LMDB refs storage backendDavid Turner, Feb 24, 2016
  47. 31/32 refs: tests for lmdb backendDavid Turner, Feb 24, 2016
  48. 32/32 tests: add ref-storage argumentDavid Turner, Feb 24, 2016
  49. SZEDER GáborFeb 29, 2016
  50. David TurnerFeb 29, 2016
  51. Ramsay JonesFeb 25, 2016
  52. David TurnerFeb 25, 2016
  53. Duy NguyenFeb 25, 2016
  54. David TurnerFeb 25, 2016
  55. Stefan BellerFeb 25, 2016
  56. Duy NguyenFeb 25, 2016

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