git/environment.c
Josh Triplett a1bea2c1fc ref namespaces: infrastructure
Add support for dividing the refs of a single repository into multiple
namespaces, each of which can have its own branches, tags, and HEAD.
Git can expose each namespace as an independent repository to pull from
and push to, while sharing the object store, and exposing all the refs
to operations such as git-gc.

Storing multiple repositories as namespaces of a single repository
avoids storing duplicate copies of the same objects, such as when
storing multiple branches of the same source.  The alternates mechanism
provides similar support for avoiding duplicates, but alternates do not
prevent duplication between new objects added to the repositories
without ongoing maintenance, while namespaces do.

To specify a namespace, set the GIT_NAMESPACE environment variable to
the namespace.  For each ref namespace, git stores the corresponding
refs in a directory under refs/namespaces/.  For example,
GIT_NAMESPACE=foo will store refs under refs/namespaces/foo/.  You can
also specify namespaces via the --namespace option to git.

Note that namespaces which include a / will expand to a hierarchy of
namespaces; for example, GIT_NAMESPACE=foo/bar will store refs under
refs/namespaces/foo/refs/namespaces/bar/.  This makes paths in
GIT_NAMESPACE behave hierarchically, so that cloning with
GIT_NAMESPACE=foo/bar produces the same result as cloning with
GIT_NAMESPACE=foo and cloning from that repo with GIT_NAMESPACE=bar.  It
also avoids ambiguity with strange namespace paths such as
foo/refs/heads/, which could otherwise generate directory/file conflicts
within the refs directory.

Add the infrastructure for ref namespaces: handle the GIT_NAMESPACE
environment variable and --namespace option, and support iterating over
refs in a namespace.

Signed-off-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Jamey Sharp <jamey@minilop.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-07-06 11:19:24 -07:00

277 lines
7.3 KiB
C

/*
* We put all the git config variables in this same object
* file, so that programs can link against the config parser
* without having to link against all the rest of git.
*
* In particular, no need to bring in libz etc unless needed,
* even if you might want to know where the git directory etc
* are.
*/
#include "cache.h"
#include "refs.h"
char git_default_email[MAX_GITNAME];
char git_default_name[MAX_GITNAME];
int user_ident_explicitly_given;
int trust_executable_bit = 1;
int trust_ctime = 1;
int has_symlinks = 1;
int minimum_abbrev = 4, default_abbrev = 7;
int ignore_case;
int assume_unchanged;
int prefer_symlink_refs;
int is_bare_repository_cfg = -1; /* unspecified */
int log_all_ref_updates = -1; /* unspecified */
int warn_ambiguous_refs = 1;
int repository_format_version;
const char *git_commit_encoding;
const char *git_log_output_encoding;
int shared_repository = PERM_UMASK;
const char *apply_default_whitespace;
const char *apply_default_ignorewhitespace;
int zlib_compression_level = Z_BEST_SPEED;
int core_compression_level;
int core_compression_seen;
int fsync_object_files;
size_t packed_git_window_size = DEFAULT_PACKED_GIT_WINDOW_SIZE;
size_t packed_git_limit = DEFAULT_PACKED_GIT_LIMIT;
size_t delta_base_cache_limit = 16 * 1024 * 1024;
unsigned long big_file_threshold = 512 * 1024 * 1024;
const char *pager_program;
int pager_use_color = 1;
const char *editor_program;
const char *askpass_program;
const char *excludes_file;
enum auto_crlf auto_crlf = AUTO_CRLF_FALSE;
int read_replace_refs = 1; /* NEEDSWORK: rename to use_replace_refs */
enum eol core_eol = EOL_UNSET;
enum safe_crlf safe_crlf = SAFE_CRLF_WARN;
unsigned whitespace_rule_cfg = WS_DEFAULT_RULE;
enum branch_track git_branch_track = BRANCH_TRACK_REMOTE;
enum rebase_setup_type autorebase = AUTOREBASE_NEVER;
enum push_default_type push_default = PUSH_DEFAULT_MATCHING;
#ifndef OBJECT_CREATION_MODE
#define OBJECT_CREATION_MODE OBJECT_CREATION_USES_HARDLINKS
#endif
enum object_creation_mode object_creation_mode = OBJECT_CREATION_MODE;
char *notes_ref_name;
int grafts_replace_parents = 1;
int core_apply_sparse_checkout;
struct startup_info *startup_info;
/* Parallel index stat data preload? */
int core_preload_index = 0;
/* This is set by setup_git_dir_gently() and/or git_default_config() */
char *git_work_tree_cfg;
static char *work_tree;
static const char *namespace;
static size_t namespace_len;
static const char *git_dir;
static char *git_object_dir, *git_index_file, *git_graft_file;
/*
* Repository-local GIT_* environment variables
* Remember to update local_repo_env_size in cache.h when
* the size of the list changes
*/
const char * const local_repo_env[LOCAL_REPO_ENV_SIZE + 1] = {
ALTERNATE_DB_ENVIRONMENT,
CONFIG_ENVIRONMENT,
CONFIG_DATA_ENVIRONMENT,
DB_ENVIRONMENT,
GIT_DIR_ENVIRONMENT,
GIT_WORK_TREE_ENVIRONMENT,
GRAFT_ENVIRONMENT,
INDEX_ENVIRONMENT,
NO_REPLACE_OBJECTS_ENVIRONMENT,
NULL
};
static char *expand_namespace(const char *raw_namespace)
{
struct strbuf buf = STRBUF_INIT;
struct strbuf **components, **c;
if (!raw_namespace || !*raw_namespace)
return xstrdup("");
strbuf_addstr(&buf, raw_namespace);
components = strbuf_split(&buf, '/');
strbuf_reset(&buf);
for (c = components; *c; c++)
if (strcmp((*c)->buf, "/") != 0)
strbuf_addf(&buf, "refs/namespaces/%s", (*c)->buf);
strbuf_list_free(components);
if (check_ref_format(buf.buf) != CHECK_REF_FORMAT_OK)
die("bad git namespace path \"%s\"", raw_namespace);
strbuf_addch(&buf, '/');
return strbuf_detach(&buf, NULL);
}
static void setup_git_env(void)
{
git_dir = getenv(GIT_DIR_ENVIRONMENT);
git_dir = git_dir ? xstrdup(git_dir) : NULL;
if (!git_dir) {
git_dir = read_gitfile_gently(DEFAULT_GIT_DIR_ENVIRONMENT);
git_dir = git_dir ? xstrdup(git_dir) : NULL;
}
if (!git_dir)
git_dir = DEFAULT_GIT_DIR_ENVIRONMENT;
git_object_dir = getenv(DB_ENVIRONMENT);
if (!git_object_dir) {
git_object_dir = xmalloc(strlen(git_dir) + 9);
sprintf(git_object_dir, "%s/objects", git_dir);
}
git_index_file = getenv(INDEX_ENVIRONMENT);
if (!git_index_file) {
git_index_file = xmalloc(strlen(git_dir) + 7);
sprintf(git_index_file, "%s/index", git_dir);
}
git_graft_file = getenv(GRAFT_ENVIRONMENT);
if (!git_graft_file)
git_graft_file = git_pathdup("info/grafts");
if (getenv(NO_REPLACE_OBJECTS_ENVIRONMENT))
read_replace_refs = 0;
namespace = expand_namespace(getenv(GIT_NAMESPACE_ENVIRONMENT));
namespace_len = strlen(namespace);
}
int is_bare_repository(void)
{
/* if core.bare is not 'false', let's see if there is a work tree */
return is_bare_repository_cfg && !get_git_work_tree();
}
int have_git_dir(void)
{
return !!git_dir;
}
const char *get_git_dir(void)
{
if (!git_dir)
setup_git_env();
return git_dir;
}
const char *get_git_namespace(void)
{
if (!namespace)
setup_git_env();
return namespace;
}
const char *strip_namespace(const char *namespaced_ref)
{
if (prefixcmp(namespaced_ref, get_git_namespace()) != 0)
return NULL;
return namespaced_ref + namespace_len;
}
static int git_work_tree_initialized;
/*
* Note. This works only before you used a work tree. This was added
* primarily to support git-clone to work in a new repository it just
* created, and is not meant to flip between different work trees.
*/
void set_git_work_tree(const char *new_work_tree)
{
if (git_work_tree_initialized) {
new_work_tree = real_path(new_work_tree);
if (strcmp(new_work_tree, work_tree))
die("internal error: work tree has already been set\n"
"Current worktree: %s\nNew worktree: %s",
work_tree, new_work_tree);
return;
}
git_work_tree_initialized = 1;
work_tree = xstrdup(real_path(new_work_tree));
}
const char *get_git_work_tree(void)
{
return work_tree;
}
char *get_object_directory(void)
{
if (!git_object_dir)
setup_git_env();
return git_object_dir;
}
int odb_mkstemp(char *template, size_t limit, const char *pattern)
{
int fd;
/*
* we let the umask do its job, don't try to be more
* restrictive except to remove write permission.
*/
int mode = 0444;
snprintf(template, limit, "%s/%s",
get_object_directory(), pattern);
fd = git_mkstemp_mode(template, mode);
if (0 <= fd)
return fd;
/* slow path */
/* some mkstemp implementations erase template on failure */
snprintf(template, limit, "%s/%s",
get_object_directory(), pattern);
safe_create_leading_directories(template);
return xmkstemp_mode(template, mode);
}
int odb_pack_keep(char *name, size_t namesz, unsigned char *sha1)
{
int fd;
snprintf(name, namesz, "%s/pack/pack-%s.keep",
get_object_directory(), sha1_to_hex(sha1));
fd = open(name, O_RDWR|O_CREAT|O_EXCL, 0600);
if (0 <= fd)
return fd;
/* slow path */
safe_create_leading_directories(name);
return open(name, O_RDWR|O_CREAT|O_EXCL, 0600);
}
char *get_index_file(void)
{
if (!git_index_file)
setup_git_env();
return git_index_file;
}
char *get_graft_file(void)
{
if (!git_graft_file)
setup_git_env();
return git_graft_file;
}
int set_git_dir(const char *path)
{
if (setenv(GIT_DIR_ENVIRONMENT, path, 1))
return error("Could not set GIT_DIR to '%s'", path);
setup_git_env();
return 0;
}
const char *get_log_output_encoding(void)
{
return git_log_output_encoding ? git_log_output_encoding
: get_commit_output_encoding();
}
const char *get_commit_output_encoding(void)
{
return git_commit_encoding ? git_commit_encoding : "UTF-8";
}