Subject: Re: [PATCH 02/26] object-store: move alt_odb_list and alt_odb_tail to object store

From: Brandon Williams <[email-masked]>
Date: Tue, 13 Feb 2018 10:51:20 -0800

On 02/12, Stefan Beller wrote:
> In a process with multiple repositories open, alternates should be
> associated to a single repository and not shared globally. Move
> alt_odb_list and alt_odb_tail into the_repository and adjust callers
> to reflect this.
> 
> Now that the alternative object data base is per repository, we're
> leaking its memory upon freeing a repository. The next patch plugs
> this hole.
> 
> No functional change intended.
> 
> Signed-off-by: Stefan Beller <[email-masked]>
> Signed-off-by: Jonathan Nieder <[email-masked]>
> ---
>  builtin/fsck.c |  4 +++-
>  cache.h        |  4 ++--
>  object-store.h |  7 ++++++-
>  packfile.c     |  3 ++-
>  sha1_file.c    | 25 ++++++++++++-------------
>  sha1_name.c    |  3 ++-
>  6 files changed, 27 insertions(+), 19 deletions(-)
> 
> diff --git a/builtin/fsck.c b/builtin/fsck.c
> index 04846d46f9..1048255da1 100644
> --- a/builtin/fsck.c
> +++ b/builtin/fsck.c
> @@ -1,5 +1,6 @@
>  #include "builtin.h"
>  #include "cache.h"
> +#include "repository.h"
>  #include "config.h"
>  #include "commit.h"
>  #include "tree.h"
> @@ -694,7 +695,8 @@ int cmd_fsck(int argc, const char **argv, const char *prefix)
>  		fsck_object_dir(get_object_directory());
>  
>  		prepare_alt_odb();
> -		for (alt = alt_odb_list; alt; alt = alt->next)
> +		for (alt = the_repository->objects.alt_odb_list;
> +				alt; alt = alt->next)
>  			fsck_object_dir(alt->path);
>  
>  		if (check_full) {
> diff --git a/cache.h b/cache.h
> index d8b975a571..918c2f15b4 100644
> --- a/cache.h
> +++ b/cache.h
> @@ -1573,7 +1573,7 @@ extern int has_dirs_only_path(const char *name, int len, int prefix_len);
>  extern void schedule_dir_for_removal(const char *name, int len);
>  extern void remove_scheduled_dirs(void);
>  
> -extern struct alternate_object_database {
> +struct alternate_object_database {
>  	struct alternate_object_database *next;
>  
>  	/* see alt_scratch_buf() */
> @@ -1591,7 +1591,7 @@ extern struct alternate_object_database {
>  	struct oid_array loose_objects_cache;
>  
>  	char path[FLEX_ARRAY];
> -} *alt_odb_list;
> +};
>  extern void prepare_alt_odb(void);
>  extern char *compute_alternate_path(const char *path, struct strbuf *err);
>  typedef int alt_odb_fn(struct alternate_object_database *, void *);
> diff --git a/object-store.h b/object-store.h
> index cf35760ceb..44b8f84753 100644
> --- a/object-store.h
> +++ b/object-store.h
> @@ -1,14 +1,19 @@
>  #ifndef OBJECT_STORE_H
>  #define OBJECT_STORE_H
>  
> +#include "cache.h"
> +

Maybe we would want to move the definition of the alternate store to
this header file?  That way we don't need to include cache.h here.

>  struct raw_object_store {
>  	/*
>  	 * Path to the repository's object store.
>  	 * Cannot be NULL after initialization.
>  	 */
>  	char *objectdir;
> +
> +	struct alternate_object_database *alt_odb_list;
> +	struct alternate_object_database **alt_odb_tail;
>  };
> -#define RAW_OBJECT_STORE_INIT { NULL }
> +#define RAW_OBJECT_STORE_INIT { NULL, NULL, NULL }
>  
>  void raw_object_store_clear(struct raw_object_store *o);
>  
> diff --git a/packfile.c b/packfile.c
> index 4a5fe7ab18..d61076faaf 100644
> --- a/packfile.c
> +++ b/packfile.c
> @@ -1,6 +1,7 @@
>  #include "cache.h"
>  #include "mru.h"
>  #include "pack.h"
> +#include "repository.h"
>  #include "dir.h"
>  #include "mergesort.h"
>  #include "packfile.h"
> @@ -880,7 +881,7 @@ void prepare_packed_git(void)
>  		return;
>  	prepare_packed_git_one(get_object_directory(), 1);
>  	prepare_alt_odb();
> -	for (alt = alt_odb_list; alt; alt = alt->next)
> +	for (alt = the_repository->objects.alt_odb_list; alt; alt = alt->next)
>  		prepare_packed_git_one(alt->path, 0);
>  	rearrange_packed_git();
>  	prepare_packed_git_mru();
> diff --git a/sha1_file.c b/sha1_file.c
> index 3da70ac650..2826d5d6ed 100644
> --- a/sha1_file.c
> +++ b/sha1_file.c
> @@ -22,6 +22,7 @@
>  #include "pack-revindex.h"
>  #include "sha1-lookup.h"
>  #include "bulk-checkin.h"
> +#include "repository.h"
>  #include "streaming.h"
>  #include "dir.h"
>  #include "mru.h"
> @@ -346,9 +347,6 @@ static const char *alt_sha1_path(struct alternate_object_database *alt,
>  	return buf->buf;
>  }
>  
> -struct alternate_object_database *alt_odb_list;
> -static struct alternate_object_database **alt_odb_tail;
> -
>  /*
>   * Return non-zero iff the path is usable as an alternate object database.
>   */
> @@ -368,7 +366,7 @@ static int alt_odb_usable(struct strbuf *path, const char *normalized_objdir)
>  	 * Prevent the common mistake of listing the same
>  	 * thing twice, or object directory itself.
>  	 */
> -	for (alt = alt_odb_list; alt; alt = alt->next) {
> +	for (alt = the_repository->objects.alt_odb_list; alt; alt = alt->next) {
>  		if (!fspathcmp(path->buf, alt->path))
>  			return 0;
>  	}
> @@ -428,8 +426,8 @@ static int link_alt_odb_entry(const char *entry, const char *relative_base,
>  	ent = alloc_alt_odb(pathbuf.buf);
>  
>  	/* add the alternate entry */
> -	*alt_odb_tail = ent;
> -	alt_odb_tail = &(ent->next);
> +	*the_repository->objects.alt_odb_tail = ent;
> +	the_repository->objects.alt_odb_tail = &(ent->next);
>  	ent->next = NULL;
>  
>  	/* recursively add alternates */
> @@ -563,7 +561,7 @@ void add_to_alternates_file(const char *reference)
>  		fprintf_or_die(out, "%s\n", reference);
>  		if (commit_lock_file(&lock))
>  			die_errno("unable to move new alternates file into place");
> -		if (alt_odb_tail)
> +		if (the_repository->objects.alt_odb_tail)
>  			link_alt_odb_entries(reference, '\n', NULL, 0);
>  	}
>  	free(alts);
> @@ -661,7 +659,7 @@ int foreach_alt_odb(alt_odb_fn fn, void *cb)
>  	int r = 0;
>  
>  	prepare_alt_odb();
> -	for (ent = alt_odb_list; ent; ent = ent->next) {
> +	for (ent = the_repository->objects.alt_odb_list; ent; ent = ent->next) {
>  		r = fn(ent, cb);
>  		if (r)
>  			break;
> @@ -673,12 +671,13 @@ void prepare_alt_odb(void)
>  {
>  	const char *alt;
>  
> -	if (alt_odb_tail)
> +	if (the_repository->objects.alt_odb_tail)
>  		return;
>  
>  	alt = getenv(ALTERNATE_DB_ENVIRONMENT);
>  
> -	alt_odb_tail = &alt_odb_list;
> +	the_repository->objects.alt_odb_tail =
> +			&the_repository->objects.alt_odb_list;
>  	link_alt_odb_entries(alt, PATH_SEP, NULL, 0);
>  
>  	read_info_alternates(get_object_directory(), 0);
> @@ -717,7 +716,7 @@ static int check_and_freshen_nonlocal(const unsigned char *sha1, int freshen)
>  {
>  	struct alternate_object_database *alt;
>  	prepare_alt_odb();
> -	for (alt = alt_odb_list; alt; alt = alt->next) {
> +	for (alt = the_repository->objects.alt_odb_list; alt; alt = alt->next) {
>  		const char *path = alt_sha1_path(alt, sha1);
>  		if (check_and_freshen_file(path, freshen))
>  			return 1;
> @@ -873,7 +872,7 @@ static int stat_sha1_file(const unsigned char *sha1, struct stat *st,
>  
>  	prepare_alt_odb();
>  	errno = ENOENT;
> -	for (alt = alt_odb_list; alt; alt = alt->next) {
> +	for (alt = the_repository->objects.alt_odb_list; alt; alt = alt->next) {
>  		*path = alt_sha1_path(alt, sha1);
>  		if (!lstat(*path, st))
>  			return 0;
> @@ -899,7 +898,7 @@ static int open_sha1_file(const unsigned char *sha1, const char **path)
>  	most_interesting_errno = errno;
>  
>  	prepare_alt_odb();
> -	for (alt = alt_odb_list; alt; alt = alt->next) {
> +	for (alt = the_repository->objects.alt_odb_list; alt; alt = alt->next) {
>  		*path = alt_sha1_path(alt, sha1);
>  		fd = git_open(*path);
>  		if (fd >= 0)
> diff --git a/sha1_name.c b/sha1_name.c
> index 611c7d24dd..957ce25680 100644
> --- a/sha1_name.c
> +++ b/sha1_name.c
> @@ -10,6 +10,7 @@
>  #include "dir.h"
>  #include "sha1-array.h"
>  #include "packfile.h"
> +#include "repository.h"
>  
>  static int get_oid_oneline(const char *, struct object_id *, struct commit_list *);
>  
> @@ -104,7 +105,7 @@ static void find_short_object_filename(struct disambiguate_state *ds)
>  		 */
>  		fakeent = alloc_alt_odb(get_object_directory());
>  	}
> -	fakeent->next = alt_odb_list;
> +	fakeent->next = the_repository->objects.alt_odb_list;
>  
>  	for (alt = fakeent; alt && !ds->ambiguous; alt = alt->next) {
>  		int pos;
> -- 
> 2.16.1.73.ga2c3e9663f.dirty
> 

-- 
Brandon Williams