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Merge branch 'mh/packed-ref-store'

Browse Source 
The "ref-store" code reorganization continues.

* mh/packed-ref-store: (32 commits)
  files-backend: cheapen refname_available check when locking refs
  packed_ref_store: handle a packed-refs file that is a symlink
  read_packed_refs(): die if `packed-refs` contains bogus data
  t3210: add some tests of bogus packed-refs file contents
  repack_without_refs(): don't lock or unlock the packed refs
  commit_packed_refs(): remove call to `packed_refs_unlock()`
  clear_packed_ref_cache(): don't protest if the lock is held
  packed_refs_unlock(), packed_refs_is_locked(): new functions
  packed_refs_lock(): report errors via a `struct strbuf *err`
  packed_refs_lock(): function renamed from lock_packed_refs()
  commit_packed_refs(): use a staging file separate from the lockfile
  commit_packed_refs(): report errors rather than dying
  packed_ref_store: make class into a subclass of `ref_store`
  packed-backend: new module for handling packed references
  packed_read_raw_ref(): new function, replacing `resolve_packed_ref()`
  packed_ref_store: support iteration
  packed_peel_ref(): new function, extracted from `files_peel_ref()`
  repack_without_refs(): take a `packed_ref_store *` parameter
  get_packed_ref(): take a `packed_ref_store *` parameter
  rollback_packed_refs(): take a `packed_ref_store *` parameter
  ...
This commit is contained in:
Junio C Hamano 2017-08-22 10:29:16 -07:00
commit 44c2339e55
8 changed files with 1098 additions and 564 deletions
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1
Makefile
View File

@ -842,6 +842,7 @@ LIB_OBJS += reflog-walk.o
LIB_OBJS += refs.o
LIB_OBJS += refs/files-backend.o
LIB_OBJS += refs/iterator.o
LIB_OBJS += refs/packed-backend.o
LIB_OBJS += refs/ref-cache.o
LIB_OBJS += ref-filter.o
LIB_OBJS += remote.o

18
refs.c
View File

@ -174,6 +174,24 @@ int refname_is_safe(const char *refname)
return 1;
}
/*
* Return true if refname, which has the specified oid and flags, can
* be resolved to an object in the database. If the referred-to object
* does not exist, emit a warning and return false.
*/
int ref_resolves_to_object(const char *refname,
const struct object_id *oid,
unsigned int flags)
{
if (flags & REF_ISBROKEN)
return 0;
if (!has_sha1_file(oid->hash)) {
error("%s does not point to a valid object!", refname);
return 0;
}
return 1;
}
char *refs_resolve_refdup(struct ref_store *refs,
const char *refname, int resolve_flags,
unsigned char *sha1, int *flags)

639
refs/files-backend.c
View File

@ -3,6 +3,7 @@
#include "../refs.h"
#include "refs-internal.h"
#include "ref-cache.h"
#include "packed-backend.h"
#include "../iterator.h"
#include "../dir-iterator.h"
#include "../lockfile.h"
@ -15,39 +16,6 @@ struct ref_lock {
struct object_id old_oid;
};
/*
* Return true if refname, which has the specified oid and flags, can
* be resolved to an object in the database. If the referred-to object
* does not exist, emit a warning and return false.
*/
static int ref_resolves_to_object(const char *refname,
const struct object_id *oid,
unsigned int flags)
{
if (flags & REF_ISBROKEN)
return 0;
if (!has_sha1_file(oid->hash)) {
error("%s does not point to a valid object!", refname);
return 0;
}
return 1;
}
struct packed_ref_cache {
struct ref_cache *cache;
/*
* Count of references to the data structure in this instance,
* including the pointer from files_ref_store::packed if any.
* The data will not be freed as long as the reference count
* is nonzero.
*/
unsigned int referrers;
/* The metadata from when this packed-refs cache was read */
struct stat_validity validity;
};
/*
* Future: need to be in "struct repository"
* when doing a full libification.
@ -58,54 +26,12 @@ struct files_ref_store {
char *gitdir;
char *gitcommondir;
char *packed_refs_path;
struct ref_cache *loose;
struct packed_ref_cache *packed;
/*
* Lock used for the "packed-refs" file. Note that this (and
* thus the enclosing `files_ref_store`) must not be freed.
*/
struct lock_file packed_refs_lock;
struct ref_store *packed_ref_store;
};
/*
* Increment the reference count of *packed_refs.
*/
static void acquire_packed_ref_cache(struct packed_ref_cache *packed_refs)
{
packed_refs->referrers++;
}
/*
* Decrease the reference count of *packed_refs. If it goes to zero,
* free *packed_refs and return true; otherwise return false.
*/
static int release_packed_ref_cache(struct packed_ref_cache *packed_refs)
{
if (!--packed_refs->referrers) {
free_ref_cache(packed_refs->cache);
stat_validity_clear(&packed_refs->validity);
free(packed_refs);
return 1;
} else {
return 0;
}
}
static void clear_packed_ref_cache(struct files_ref_store *refs)
{
if (refs->packed) {
struct packed_ref_cache *packed_refs = refs->packed;
if (is_lock_file_locked(&refs->packed_refs_lock))
die("BUG: packed-ref cache cleared while locked");
refs->packed = NULL;
release_packed_ref_cache(packed_refs);
}
}
static void clear_loose_ref_cache(struct files_ref_store *refs)
{
if (refs->loose) {
@ -132,7 +58,8 @@ static struct ref_store *files_ref_store_create(const char *gitdir,
get_common_dir_noenv(&sb, gitdir);
refs->gitcommondir = strbuf_detach(&sb, NULL);
strbuf_addf(&sb, "%s/packed-refs", refs->gitcommondir);
refs->packed_refs_path = strbuf_detach(&sb, NULL);
refs->packed_ref_store = packed_ref_store_create(sb.buf, flags);
strbuf_release(&sb);
return ref_store;
}
@ -175,156 +102,6 @@ static struct files_ref_store *files_downcast(struct ref_store *ref_store,
return refs;
}
/* The length of a peeled reference line in packed-refs, including EOL: */
#define PEELED_LINE_LENGTH 42
/*
* The packed-refs header line that we write out. Perhaps other
* traits will be added later. The trailing space is required.
*/
static const char PACKED_REFS_HEADER[] =
"# pack-refs with: peeled fully-peeled \n";
/*
* Parse one line from a packed-refs file. Write the SHA1 to sha1.
* Return a pointer to the refname within the line (null-terminated),
* or NULL if there was a problem.
*/
static const char *parse_ref_line(struct strbuf *line, struct object_id *oid)
{
const char *ref;
if (parse_oid_hex(line->buf, oid, &ref) < 0)
return NULL;
if (!isspace(*ref++))
return NULL;
if (isspace(*ref))
return NULL;
if (line->buf[line->len - 1] != '\n')
return NULL;
line->buf[--line->len] = 0;
return ref;
}
/*
* Read from `packed_refs_file` into a newly-allocated
* `packed_ref_cache` and return it. The return value will already
* have its reference count incremented.
*
* A comment line of the form "# pack-refs with: " may contain zero or
* more traits. We interpret the traits as follows:
*
* No traits:
*
* Probably no references are peeled. But if the file contains a
* peeled value for a reference, we will use it.
*
* peeled:
*
* References under "refs/tags/", if they *can* be peeled, *are*
* peeled in this file. References outside of "refs/tags/" are
* probably not peeled even if they could have been, but if we find
* a peeled value for such a reference we will use it.
*
* fully-peeled:
*
* All references in the file that can be peeled are peeled.
* Inversely (and this is more important), any references in the
* file for which no peeled value is recorded is not peelable. This
* trait should typically be written alongside "peeled" for
* compatibility with older clients, but we do not require it
* (i.e., "peeled" is a no-op if "fully-peeled" is set).
*/
static struct packed_ref_cache *read_packed_refs(const char *packed_refs_file)
{
FILE *f;
struct packed_ref_cache *packed_refs = xcalloc(1, sizeof(*packed_refs));
struct ref_entry *last = NULL;
struct strbuf line = STRBUF_INIT;
enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled = PEELED_NONE;
struct ref_dir *dir;
acquire_packed_ref_cache(packed_refs);
packed_refs->cache = create_ref_cache(NULL, NULL);
packed_refs->cache->root->flag &= ~REF_INCOMPLETE;
f = fopen(packed_refs_file, "r");
if (!f) {
if (errno == ENOENT) {
/*
* This is OK; it just means that no
* "packed-refs" file has been written yet,
* which is equivalent to it being empty.
*/
return packed_refs;
} else {
die_errno("couldn't read %s", packed_refs_file);
}
}
stat_validity_update(&packed_refs->validity, fileno(f));
dir = get_ref_dir(packed_refs->cache->root);
while (strbuf_getwholeline(&line, f, '\n') != EOF) {
struct object_id oid;
const char *refname;
const char *traits;
if (skip_prefix(line.buf, "# pack-refs with:", &traits)) {
if (strstr(traits, " fully-peeled "))
peeled = PEELED_FULLY;
else if (strstr(traits, " peeled "))
peeled = PEELED_TAGS;
/* perhaps other traits later as well */
continue;
}
refname = parse_ref_line(&line, &oid);
if (refname) {
int flag = REF_ISPACKED;
if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
if (!refname_is_safe(refname))
die("packed refname is dangerous: %s", refname);
oidclr(&oid);
flag |= REF_BAD_NAME | REF_ISBROKEN;
}
last = create_ref_entry(refname, &oid, flag);
if (peeled == PEELED_FULLY ||
(peeled == PEELED_TAGS && starts_with(refname, "refs/tags/")))
last->flag |= REF_KNOWS_PEELED;
add_ref_entry(dir, last);
continue;
}
if (last &&
line.buf[0] == '^' &&
line.len == PEELED_LINE_LENGTH &&
line.buf[PEELED_LINE_LENGTH - 1] == '\n' &&
!get_oid_hex(line.buf + 1, &oid)) {
oidcpy(&last->u.value.peeled, &oid);
/*
* Regardless of what the file header said,
* we definitely know the value of *this*
* reference:
*/
last->flag |= REF_KNOWS_PEELED;
}
}
fclose(f);
strbuf_release(&line);
return packed_refs;
}
static const char *files_packed_refs_path(struct files_ref_store *refs)
{
return refs->packed_refs_path;
}
static void files_reflog_path(struct files_ref_store *refs,
struct strbuf *sb,
const char *refname)
@ -370,70 +147,6 @@ static void files_ref_path(struct files_ref_store *refs,
}
}
/*
* Check that the packed refs cache (if any) still reflects the
* contents of the file. If not, clear the cache.
*/
static void validate_packed_ref_cache(struct files_ref_store *refs)
{
if (refs->packed &&
!stat_validity_check(&refs->packed->validity,
files_packed_refs_path(refs)))
clear_packed_ref_cache(refs);
}
/*
* Get the packed_ref_cache for the specified files_ref_store,
* creating and populating it if it hasn't been read before or if the
* file has been changed (according to its `validity` field) since it
* was last read. On the other hand, if we hold the lock, then assume
* that the file hasn't been changed out from under us, so skip the
* extra `stat()` call in `stat_validity_check()`.
*/
static struct packed_ref_cache *get_packed_ref_cache(struct files_ref_store *refs)
{
const char *packed_refs_file = files_packed_refs_path(refs);
if (!is_lock_file_locked(&refs->packed_refs_lock))
validate_packed_ref_cache(refs);
if (!refs->packed)
refs->packed = read_packed_refs(packed_refs_file);
return refs->packed;
}
static struct ref_dir *get_packed_ref_dir(struct packed_ref_cache *packed_ref_cache)
{
return get_ref_dir(packed_ref_cache->cache->root);
}
static struct ref_dir *get_packed_refs(struct files_ref_store *refs)
{
return get_packed_ref_dir(get_packed_ref_cache(refs));
}
/*
* Add a reference to the in-memory packed reference cache. This may
* only be called while the packed-refs file is locked (see
* lock_packed_refs()). To actually write the packed-refs file, call
* commit_packed_refs().
*/
static void add_packed_ref(struct files_ref_store *refs,
const char *refname, const struct object_id *oid)
{
struct packed_ref_cache *packed_ref_cache = get_packed_ref_cache(refs);
if (!is_lock_file_locked(&refs->packed_refs_lock))
die("BUG: packed refs not locked");
if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
die("Reference has invalid format: '%s'", refname);
add_ref_entry(get_packed_ref_dir(packed_ref_cache),
create_ref_entry(refname, oid, REF_ISPACKED));
}
/*
* Read the loose references from the namespace dirname into dir
* (without recursing). dirname must end with '/'. dir must be the
@ -556,39 +269,6 @@ static struct ref_cache *get_loose_ref_cache(struct files_ref_store *refs)
return refs->loose;
}
/*
* Return the ref_entry for the given refname from the packed
* references. If it does not exist, return NULL.
*/
static struct ref_entry *get_packed_ref(struct files_ref_store *refs,
const char *refname)
{
return find_ref_entry(get_packed_refs(refs), refname);
}
/*
* A loose ref file doesn't exist; check for a packed ref.
*/
static int resolve_packed_ref(struct files_ref_store *refs,
const char *refname,
unsigned char *sha1, unsigned int *flags)
{
struct ref_entry *entry;
/*
* The loose reference file does not exist; check for a packed
* reference.
*/
entry = get_packed_ref(refs, refname);
if (entry) {
hashcpy(sha1, entry->u.value.oid.hash);
*flags |= REF_ISPACKED;
return 0;
}
/* refname is not a packed reference. */
return -1;
}
static int files_read_raw_ref(struct ref_store *ref_store,
const char *refname, unsigned char *sha1,
struct strbuf *referent, unsigned int *type)
@ -632,7 +312,8 @@ stat_ref:
if (lstat(path, &st) < 0) {
if (errno != ENOENT)
goto out;
if (resolve_packed_ref(refs, refname, sha1, type)) {
if (refs_read_raw_ref(refs->packed_ref_store, refname,
sha1, referent, type)) {
errno = ENOENT;
goto out;
}
@ -671,7 +352,8 @@ stat_ref:
* ref is supposed to be, there could still be a
* packed ref:
*/
if (resolve_packed_ref(refs, refname, sha1, type)) {
if (refs_read_raw_ref(refs->packed_ref_store, refname,
sha1, referent, type)) {
errno = EISDIR;
goto out;
}
@ -950,11 +632,11 @@ retry:
/*
* If the ref did not exist and we are creating it,
* make sure there is no existing ref that conflicts
* with refname:
* make sure there is no existing packed ref that
* conflicts with refname:
*/
if (refs_verify_refname_available(
&refs->base, refname,
refs->packed_ref_store, refname,
extras, skip, err))
goto error_return;
}
@ -1001,15 +683,9 @@ static int files_peel_ref(struct ref_store *ref_store,
* be expensive and (b) loose references anyway usually do not
* have REF_KNOWS_PEELED.
*/
if (flag & REF_ISPACKED) {
struct ref_entry *r = get_packed_ref(refs, refname);
if (r) {
if (peel_entry(r, 0))
return -1;
hashcpy(sha1, r->u.value.peeled.hash);
return 0;
}
}
if (flag & REF_ISPACKED &&
!refs_peel_ref(refs->packed_ref_store, refname, sha1))
return 0;
return peel_object(base, sha1);
}
@ -1017,7 +693,6 @@ static int files_peel_ref(struct ref_store *ref_store,
struct files_ref_iterator {
struct ref_iterator base;
struct packed_ref_cache *packed_ref_cache;
struct ref_iterator *iter0;
unsigned int flags;
};
@ -1070,7 +745,6 @@ static int files_ref_iterator_abort(struct ref_iterator *ref_iterator)
if (iter->iter0)
ok = ref_iterator_abort(iter->iter0);
release_packed_ref_cache(iter->packed_ref_cache);
base_ref_iterator_free(ref_iterator);
return ok;
}
@ -1112,18 +786,28 @@ static struct ref_iterator *files_ref_iterator_begin(
* (If they've already been read, that's OK; we only need to
* guarantee that they're read before the packed refs, not
* *how much* before.) After that, we call
* get_packed_ref_cache(), which internally checks whether the
* packed-ref cache is up to date with what is on disk, and
* re-reads it if not.
* packed_ref_iterator_begin(), which internally checks
* whether the packed-ref cache is up to date with what is on
* disk, and re-reads it if not.
*/
loose_iter = cache_ref_iterator_begin(get_loose_ref_cache(refs),
prefix, 1);
iter->packed_ref_cache = get_packed_ref_cache(refs);
acquire_packed_ref_cache(iter->packed_ref_cache);
packed_iter = cache_ref_iterator_begin(iter->packed_ref_cache->cache,
prefix, 0);
/*
* The packed-refs file might contain broken references, for
* example an old version of a reference that points at an
* object that has since been garbage-collected. This is OK as
* long as there is a corresponding loose reference that
* overrides it, and we don't want to emit an error message in
* this case. So ask the packed_ref_store for all of its
* references, and (if needed) do our own check for broken
* ones in files_ref_iterator_advance(), after we have merged
* the packed and loose references.
*/
packed_iter = refs_ref_iterator_begin(
refs->packed_ref_store, prefix, 0,
DO_FOR_EACH_INCLUDE_BROKEN);
iter->iter0 = overlay_ref_iterator_begin(loose_iter, packed_iter);
iter->flags = flags;
@ -1255,7 +939,7 @@ static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
* our refname.
*/
if (is_null_oid(&lock->old_oid) &&
refs_verify_refname_available(&refs->base, refname,
refs_verify_refname_available(refs->packed_ref_store, refname,
extras, skip, err)) {
last_errno = ENOTDIR;
goto error_return;
@ -1287,124 +971,6 @@ static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
return lock;
}
/*
* Write an entry to the packed-refs file for the specified refname.
* If peeled is non-NULL, write it as the entry's peeled value.
*/
static void write_packed_entry(FILE *fh, const char *refname,
const unsigned char *sha1,
const unsigned char *peeled)
{
fprintf_or_die(fh, "%s %s\n", sha1_to_hex(sha1), refname);
if (peeled)
fprintf_or_die(fh, "^%s\n", sha1_to_hex(peeled));
}
/*
* Lock the packed-refs file for writing. Flags is passed to
* hold_lock_file_for_update(). Return 0 on success. On errors, set
* errno appropriately and return a nonzero value.
*/
static int lock_packed_refs(struct files_ref_store *refs, int flags)
{
static int timeout_configured = 0;
static int timeout_value = 1000;
struct packed_ref_cache *packed_ref_cache;
files_assert_main_repository(refs, "lock_packed_refs");
if (!timeout_configured) {
git_config_get_int("core.packedrefstimeout", &timeout_value);
timeout_configured = 1;
}
if (hold_lock_file_for_update_timeout(
&refs->packed_refs_lock, files_packed_refs_path(refs),
flags, timeout_value) < 0)
return -1;
/*
* Now that we hold the `packed-refs` lock, make sure that our
* cache matches the current version of the file. Normally
* `get_packed_ref_cache()` does that for us, but that
* function assumes that when the file is locked, any existing
* cache is still valid. We've just locked the file, but it
* might have changed the moment *before* we locked it.
*/
validate_packed_ref_cache(refs);
packed_ref_cache = get_packed_ref_cache(refs);
/* Increment the reference count to prevent it from being freed: */
acquire_packed_ref_cache(packed_ref_cache);
return 0;
}
/*
* Write the current version of the packed refs cache from memory to
* disk. The packed-refs file must already be locked for writing (see
* lock_packed_refs()). Return zero on success. On errors, set errno
* and return a nonzero value
*/
static int commit_packed_refs(struct files_ref_store *refs)
{
struct packed_ref_cache *packed_ref_cache =
get_packed_ref_cache(refs);
int ok, error = 0;
int save_errno = 0;
FILE *out;
struct ref_iterator *iter;
files_assert_main_repository(refs, "commit_packed_refs");
if (!is_lock_file_locked(&refs->packed_refs_lock))
die("BUG: packed-refs not locked");
out = fdopen_lock_file(&refs->packed_refs_lock, "w");
if (!out)
die_errno("unable to fdopen packed-refs descriptor");
fprintf_or_die(out, "%s", PACKED_REFS_HEADER);
iter = cache_ref_iterator_begin(packed_ref_cache->cache, NULL, 0);
while ((ok = ref_iterator_advance(iter)) == ITER_OK) {
struct object_id peeled;
int peel_error = ref_iterator_peel(iter, &peeled);
write_packed_entry(out, iter->refname, iter->oid->hash,
peel_error ? NULL : peeled.hash);
}
if (ok != ITER_DONE)
die("error while iterating over references");
if (commit_lock_file(&refs->packed_refs_lock)) {
save_errno = errno;
error = -1;
}
release_packed_ref_cache(packed_ref_cache);
errno = save_errno;
return error;
}
/*
* Rollback the lockfile for the packed-refs file, and discard the
* in-memory packed reference cache. (The packed-refs file will be
* read anew if it is needed again after this function is called.)
*/
static void rollback_packed_refs(struct files_ref_store *refs)
{
struct packed_ref_cache *packed_ref_cache =
get_packed_ref_cache(refs);
files_assert_main_repository(refs, "rollback_packed_refs");
if (!is_lock_file_locked(&refs->packed_refs_lock))
die("BUG: packed-refs not locked");
rollback_lock_file(&refs->packed_refs_lock);
release_packed_ref_cache(packed_ref_cache);
clear_packed_ref_cache(refs);
}
struct ref_to_prune {
struct ref_to_prune *next;
unsigned char sha1[20];
@ -1527,12 +1093,11 @@ static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
files_downcast(ref_store, REF_STORE_WRITE | REF_STORE_ODB,
"pack_refs");
struct ref_iterator *iter;
struct ref_dir *packed_refs;
int ok;
struct ref_to_prune *refs_to_prune = NULL;
struct strbuf err = STRBUF_INIT;
lock_packed_refs(refs, LOCK_DIE_ON_ERROR);
packed_refs = get_packed_refs(refs);
packed_refs_lock(refs->packed_ref_store, LOCK_DIE_ON_ERROR, &err);
iter = cache_ref_iterator_begin(get_loose_ref_cache(refs), NULL, 0);
while ((ok = ref_iterator_advance(iter)) == ITER_OK) {
@ -1541,8 +1106,6 @@ static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
* in the packed ref cache. If the reference should be
* pruned, also add it to refs_to_prune.
*/
struct ref_entry *packed_entry;
if (!should_pack_ref(iter->refname, iter->oid, iter->flags,
flags))
continue;
@ -1553,17 +1116,7 @@ static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
* we don't copy the peeled status, because we want it
* to be re-peeled.
*/
packed_entry = find_ref_entry(packed_refs, iter->refname);
if (packed_entry) {
/* Overwrite existing packed entry with info from loose entry */
packed_entry->flag = REF_ISPACKED;
oidcpy(&packed_entry->u.value.oid, iter->oid);
} else {
packed_entry = create_ref_entry(iter->refname, iter->oid,
REF_ISPACKED);
add_ref_entry(packed_refs, packed_entry);
}
oidclr(&packed_entry->u.value.peeled);
add_packed_ref(refs->packed_ref_store, iter->refname, iter->oid);
/* Schedule the loose reference for pruning if requested. */
if ((flags & PACK_REFS_PRUNE)) {
@ -1577,69 +1130,15 @@ static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
if (ok != ITER_DONE)
die("error while iterating over references");
if (commit_packed_refs(refs))
die_errno("unable to overwrite old ref-pack file");
if (commit_packed_refs(refs->packed_ref_store, &err))
die("unable to overwrite old ref-pack file: %s", err.buf);
packed_refs_unlock(refs->packed_ref_store);
prune_refs(refs, refs_to_prune);
strbuf_release(&err);
return 0;
}
/*
* Rewrite the packed-refs file, omitting any refs listed in
* 'refnames'. On error, leave packed-refs unchanged, write an error
* message to 'err', and return a nonzero value.
*
* The refs in 'refnames' needn't be sorted. `err` must not be NULL.
*/
static int repack_without_refs(struct files_ref_store *refs,
struct string_list *refnames, struct strbuf *err)
{
struct ref_dir *packed;
struct string_list_item *refname;
int ret, needs_repacking = 0, removed = 0;
files_assert_main_repository(refs, "repack_without_refs");
assert(err);
/* Look for a packed ref */
for_each_string_list_item(refname, refnames) {
if (get_packed_ref(refs, refname->string)) {
needs_repacking = 1;
break;
}
}
/* Avoid locking if we have nothing to do */
if (!needs_repacking)
return 0; /* no refname exists in packed refs */
if (lock_packed_refs(refs, 0)) {
unable_to_lock_message(files_packed_refs_path(refs), errno, err);
return -1;
}
packed = get_packed_refs(refs);
/* Remove refnames from the cache */
for_each_string_list_item(refname, refnames)
if (remove_entry_from_dir(packed, refname->string) != -1)
removed = 1;
if (!removed) {
/*
* All packed entries disappeared while we were
* acquiring the lock.
*/
rollback_packed_refs(refs);
return 0;
}
/* Write what remains */
ret = commit_packed_refs(refs);
if (ret)
strbuf_addf(err, "unable to overwrite old ref-pack file: %s",
strerror(errno));
return ret;
}
static int files_delete_refs(struct ref_store *ref_store, const char *msg,
struct string_list *refnames, unsigned int flags)
{
@ -1651,24 +1150,16 @@ static int files_delete_refs(struct ref_store *ref_store, const char *msg,
if (!refnames->nr)
return 0;
result = repack_without_refs(refs, refnames, &err);
if (result) {
/*
* If we failed to rewrite the packed-refs file, then
* it is unsafe to try to remove loose refs, because
* doing so might expose an obsolete packed value for
* a reference that might even point at an object that
* has been garbage collected.
*/
if (refnames->nr == 1)
error(_("could not delete reference %s: %s"),
refnames->items[0].string, err.buf);
else
error(_("could not delete references: %s"), err.buf);
if (packed_refs_lock(refs->packed_ref_store, 0, &err))
goto error;
goto out;
if (repack_without_refs(refs->packed_ref_store, refnames, &err)) {
packed_refs_unlock(refs->packed_ref_store);
goto error;
}
packed_refs_unlock(refs->packed_ref_store);
for (i = 0; i < refnames->nr; i++) {
const char *refname = refnames->items[i].string;
@ -1676,9 +1167,24 @@ static int files_delete_refs(struct ref_store *ref_store, const char *msg,
result |= error(_("could not remove reference %s"), refname);
}
out:
strbuf_release(&err);
return result;
error:
/*
* If we failed to rewrite the packed-refs file, then it is
* unsafe to try to remove loose refs, because doing so might
* expose an obsolete packed value for a reference that might
* even point at an object that has been garbage collected.
*/
if (refnames->nr == 1)
error(_("could not delete reference %s: %s"),
refnames->items[0].string, err.buf);
else
error(_("could not delete references: %s"), err.buf);
strbuf_release(&err);
return -1;
}
/*
@ -3070,11 +2576,19 @@ static int files_transaction_finish(struct ref_store *ref_store,
}
}
if (repack_without_refs(refs, &refs_to_delete, err)) {
if (packed_refs_lock(refs->packed_ref_store, 0, err)) {
ret = TRANSACTION_GENERIC_ERROR;
goto cleanup;
}
if (repack_without_refs(refs->packed_ref_store, &refs_to_delete, err)) {
ret = TRANSACTION_GENERIC_ERROR;
packed_refs_unlock(refs->packed_ref_store);
goto cleanup;
}
packed_refs_unlock(refs->packed_ref_store);
/* Delete the reflogs of any references that were deleted: */
for_each_string_list_item(ref_to_delete, &refs_to_delete) {
strbuf_reset(&sb);
@ -3181,9 +2695,7 @@ static int files_initial_transaction_commit(struct ref_store *ref_store,
}
}
if (lock_packed_refs(refs, 0)) {
strbuf_addf(err, "unable to lock packed-refs file: %s",
strerror(errno));
if (packed_refs_lock(refs->packed_ref_store, 0, err)) {
ret = TRANSACTION_GENERIC_ERROR;
goto cleanup;
}
@ -3193,18 +2705,17 @@ static int files_initial_transaction_commit(struct ref_store *ref_store,
if ((update->flags & REF_HAVE_NEW) &&
!is_null_oid(&update->new_oid))
add_packed_ref(refs, update->refname,
add_packed_ref(refs->packed_ref_store, update->refname,
&update->new_oid);
}
if (commit_packed_refs(refs)) {
strbuf_addf(err, "unable to commit packed-refs file: %s",
strerror(errno));
if (commit_packed_refs(refs->packed_ref_store, err)) {
ret = TRANSACTION_GENERIC_ERROR;
goto cleanup;
}
cleanup:
packed_refs_unlock(refs->packed_ref_store);
transaction->state = REF_TRANSACTION_CLOSED;
string_list_clear(&affected_refnames, 0);
return ret;

885
refs/packed-backend.c Normal file
View File

@ -0,0 +1,885 @@
#include "../cache.h"
#include "../config.h"
#include "../refs.h"
#include "refs-internal.h"
#include "ref-cache.h"
#include "packed-backend.h"
#include "../iterator.h"
#include "../lockfile.h"
struct packed_ref_cache {
struct ref_cache *cache;
/*
* Count of references to the data structure in this instance,
* including the pointer from files_ref_store::packed if any.
* The data will not be freed as long as the reference count
* is nonzero.
*/
unsigned int referrers;
/* The metadata from when this packed-refs cache was read */
struct stat_validity validity;
};
/*
* Increment the reference count of *packed_refs.
*/
static void acquire_packed_ref_cache(struct packed_ref_cache *packed_refs)
{
packed_refs->referrers++;
}
/*
* Decrease the reference count of *packed_refs. If it goes to zero,
* free *packed_refs and return true; otherwise return false.
*/
static int release_packed_ref_cache(struct packed_ref_cache *packed_refs)
{
if (!--packed_refs->referrers) {
free_ref_cache(packed_refs->cache);
stat_validity_clear(&packed_refs->validity);
free(packed_refs);
return 1;
} else {
return 0;
}
}
/*
* A container for `packed-refs`-related data. It is not (yet) a
* `ref_store`.
*/
struct packed_ref_store {
struct ref_store base;
unsigned int store_flags;
/* The path of the "packed-refs" file: */
char *path;
/*
* A cache of the values read from the `packed-refs` file, if
* it might still be current; otherwise, NULL.
*/
struct packed_ref_cache *cache;
/*
* Lock used for the "packed-refs" file. Note that this (and
* thus the enclosing `packed_ref_store`) must not be freed.
*/
struct lock_file lock;
/*
* Temporary file used when rewriting new contents to the
* "packed-refs" file. Note that this (and thus the enclosing
* `packed_ref_store`) must not be freed.
*/
struct tempfile tempfile;
};
struct ref_store *packed_ref_store_create(const char *path,
unsigned int store_flags)
{
struct packed_ref_store *refs = xcalloc(1, sizeof(*refs));
struct ref_store *ref_store = (struct ref_store *)refs;
base_ref_store_init(ref_store, &refs_be_packed);
refs->store_flags = store_flags;
refs->path = xstrdup(path);
return ref_store;
}
/*
* Die if refs is not the main ref store. caller is used in any
* necessary error messages.
*/
static void packed_assert_main_repository(struct packed_ref_store *refs,
const char *caller)
{
if (refs->store_flags & REF_STORE_MAIN)
return;
die("BUG: operation %s only allowed for main ref store", caller);
}
/*
* Downcast `ref_store` to `packed_ref_store`. Die if `ref_store` is
* not a `packed_ref_store`. Also die if `packed_ref_store` doesn't
* support at least the flags specified in `required_flags`. `caller`
* is used in any necessary error messages.
*/
static struct packed_ref_store *packed_downcast(struct ref_store *ref_store,
unsigned int required_flags,
const char *caller)
{
struct packed_ref_store *refs;
if (ref_store->be != &refs_be_packed)
die("BUG: ref_store is type \"%s\" not \"packed\" in %s",
ref_store->be->name, caller);
refs = (struct packed_ref_store *)ref_store;
if ((refs->store_flags & required_flags) != required_flags)
die("BUG: unallowed operation (%s), requires %x, has %x\n",
caller, required_flags, refs->store_flags);
return refs;
}
static void clear_packed_ref_cache(struct packed_ref_store *refs)
{
if (refs->cache) {
struct packed_ref_cache *cache = refs->cache;
refs->cache = NULL;
release_packed_ref_cache(cache);
}
}
/* The length of a peeled reference line in packed-refs, including EOL: */
#define PEELED_LINE_LENGTH 42
/*
* Parse one line from a packed-refs file. Write the SHA1 to sha1.
* Return a pointer to the refname within the line (null-terminated),
* or NULL if there was a problem.
*/
static const char *parse_ref_line(struct strbuf *line, struct object_id *oid)
{
const char *ref;
if (parse_oid_hex(line->buf, oid, &ref) < 0)
return NULL;
if (!isspace(*ref++))
return NULL;
if (isspace(*ref))
return NULL;
if (line->buf[line->len - 1] != '\n')
return NULL;
line->buf[--line->len] = 0;
return ref;
}
/*
* Read from `packed_refs_file` into a newly-allocated
* `packed_ref_cache` and return it. The return value will already
* have its reference count incremented.
*
* A comment line of the form "# pack-refs with: " may contain zero or
* more traits. We interpret the traits as follows:
*
* No traits:
*
* Probably no references are peeled. But if the file contains a
* peeled value for a reference, we will use it.
*
* peeled:
*
* References under "refs/tags/", if they *can* be peeled, *are*
* peeled in this file. References outside of "refs/tags/" are
* probably not peeled even if they could have been, but if we find
* a peeled value for such a reference we will use it.
*
* fully-peeled:
*
* All references in the file that can be peeled are peeled.
* Inversely (and this is more important), any references in the
* file for which no peeled value is recorded is not peelable. This
* trait should typically be written alongside "peeled" for
* compatibility with older clients, but we do not require it
* (i.e., "peeled" is a no-op if "fully-peeled" is set).
*/
static struct packed_ref_cache *read_packed_refs(const char *packed_refs_file)
{
FILE *f;
struct packed_ref_cache *packed_refs = xcalloc(1, sizeof(*packed_refs));
struct ref_entry *last = NULL;
struct strbuf line = STRBUF_INIT;
enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled = PEELED_NONE;
struct ref_dir *dir;
acquire_packed_ref_cache(packed_refs);
packed_refs->cache = create_ref_cache(NULL, NULL);
packed_refs->cache->root->flag &= ~REF_INCOMPLETE;
f = fopen(packed_refs_file, "r");
if (!f) {
if (errno == ENOENT) {
/*
* This is OK; it just means that no
* "packed-refs" file has been written yet,
* which is equivalent to it being empty.
*/
return packed_refs;
} else {
die_errno("couldn't read %s", packed_refs_file);
}
}
stat_validity_update(&packed_refs->validity, fileno(f));
dir = get_ref_dir(packed_refs->cache->root);
while (strbuf_getwholeline(&line, f, '\n') != EOF) {
struct object_id oid;
const char *refname;
const char *traits;
if (!line.len || line.buf[line.len - 1] != '\n')
die("unterminated line in %s: %s", packed_refs_file, line.buf);
if (skip_prefix(line.buf, "# pack-refs with:", &traits)) {
if (strstr(traits, " fully-peeled "))
peeled = PEELED_FULLY;
else if (strstr(traits, " peeled "))
peeled = PEELED_TAGS;
/* perhaps other traits later as well */
continue;
}
refname = parse_ref_line(&line, &oid);
if (refname) {
int flag = REF_ISPACKED;
if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
if (!refname_is_safe(refname))
die("packed refname is dangerous: %s", refname);
oidclr(&oid);
flag |= REF_BAD_NAME | REF_ISBROKEN;
}
last = create_ref_entry(refname, &oid, flag);
if (peeled == PEELED_FULLY ||
(peeled == PEELED_TAGS && starts_with(refname, "refs/tags/")))
last->flag |= REF_KNOWS_PEELED;
add_ref_entry(dir, last);
} else if (last &&
line.buf[0] == '^' &&
line.len == PEELED_LINE_LENGTH &&
line.buf[PEELED_LINE_LENGTH - 1] == '\n' &&
!get_oid_hex(line.buf + 1, &oid)) {
oidcpy(&last->u.value.peeled, &oid);
/*
* Regardless of what the file header said,
* we definitely know the value of *this*
* reference:
*/
last->flag |= REF_KNOWS_PEELED;
} else {
strbuf_setlen(&line, line.len - 1);
die("unexpected line in %s: %s", packed_refs_file, line.buf);
}
}
fclose(f);
strbuf_release(&line);
return packed_refs;
}
/*
* Check that the packed refs cache (if any) still reflects the
* contents of the file. If not, clear the cache.
*/
static void validate_packed_ref_cache(struct packed_ref_store *refs)
{
if (refs->cache &&
!stat_validity_check(&refs->cache->validity, refs->path))
clear_packed_ref_cache(refs);
}
/*
* Get the packed_ref_cache for the specified packed_ref_store,
* creating and populating it if it hasn't been read before or if the
* file has been changed (according to its `validity` field) since it
* was last read. On the other hand, if we hold the lock, then assume
* that the file hasn't been changed out from under us, so skip the
* extra `stat()` call in `stat_validity_check()`.
*/
static struct packed_ref_cache *get_packed_ref_cache(struct packed_ref_store *refs)
{
if (!is_lock_file_locked(&refs->lock))
validate_packed_ref_cache(refs);
if (!refs->cache)
refs->cache = read_packed_refs(refs->path);
return refs->cache;
}
static struct ref_dir *get_packed_ref_dir(struct packed_ref_cache *packed_ref_cache)
{
return get_ref_dir(packed_ref_cache->cache->root);
}
static struct ref_dir *get_packed_refs(struct packed_ref_store *refs)
{
return get_packed_ref_dir(get_packed_ref_cache(refs));
}
/*
* Add or overwrite a reference in the in-memory packed reference
* cache. This may only be called while the packed-refs file is locked
* (see packed_refs_lock()). To actually write the packed-refs file,
* call commit_packed_refs().
*/
void add_packed_ref(struct ref_store *ref_store,
const char *refname, const struct object_id *oid)
{
struct packed_ref_store *refs =
packed_downcast(ref_store, REF_STORE_WRITE,
"add_packed_ref");
struct ref_dir *packed_refs;
struct ref_entry *packed_entry;
if (!is_lock_file_locked(&refs->lock))
die("BUG: packed refs not locked");
if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
die("Reference has invalid format: '%s'", refname);
packed_refs = get_packed_refs(refs);
packed_entry = find_ref_entry(packed_refs, refname);
if (packed_entry) {
/* Overwrite the existing entry: */
oidcpy(&packed_entry->u.value.oid, oid);
packed_entry->flag = REF_ISPACKED;
oidclr(&packed_entry->u.value.peeled);
} else {
packed_entry = create_ref_entry(refname, oid, REF_ISPACKED);
add_ref_entry(packed_refs, packed_entry);
}
}
/*
* Return the ref_entry for the given refname from the packed
* references. If it does not exist, return NULL.
*/
static struct ref_entry *get_packed_ref(struct packed_ref_store *refs,
const char *refname)
{
return find_ref_entry(get_packed_refs(refs), refname);
}
static int packed_read_raw_ref(struct ref_store *ref_store,
const char *refname, unsigned char *sha1,
struct strbuf *referent, unsigned int *type)
{
struct packed_ref_store *refs =
packed_downcast(ref_store, REF_STORE_READ, "read_raw_ref");
struct ref_entry *entry;
*type = 0;
entry = get_packed_ref(refs, refname);
if (!entry) {
errno = ENOENT;
return -1;
}
hashcpy(sha1, entry->u.value.oid.hash);
*type = REF_ISPACKED;
return 0;
}
static int packed_peel_ref(struct ref_store *ref_store,
const char *refname, unsigned char *sha1)
{
struct packed_ref_store *refs =
packed_downcast(ref_store, REF_STORE_READ | REF_STORE_ODB,
"peel_ref");
struct ref_entry *r = get_packed_ref(refs, refname);
if (!r || peel_entry(r, 0))
return -1;
hashcpy(sha1, r->u.value.peeled.hash);
return 0;
}
struct packed_ref_iterator {
struct ref_iterator base;
struct packed_ref_cache *cache;
struct ref_iterator *iter0;
unsigned int flags;
};
static int packed_ref_iterator_advance(struct ref_iterator *ref_iterator)
{
struct packed_ref_iterator *iter =
(struct packed_ref_iterator *)ref_iterator;
int ok;
while ((ok = ref_iterator_advance(iter->iter0)) == ITER_OK) {
if (iter->flags & DO_FOR_EACH_PER_WORKTREE_ONLY &&
ref_type(iter->iter0->refname) != REF_TYPE_PER_WORKTREE)
continue;
if (!(iter->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&
!ref_resolves_to_object(iter->iter0->refname,
iter->iter0->oid,
iter->iter0->flags))
continue;
iter->base.refname = iter->iter0->refname;
iter->base.oid = iter->iter0->oid;
iter->base.flags = iter->iter0->flags;
return ITER_OK;
}
iter->iter0 = NULL;
if (ref_iterator_abort(ref_iterator) != ITER_DONE)
ok = ITER_ERROR;
return ok;
}
static int packed_ref_iterator_peel(struct ref_iterator *ref_iterator,
struct object_id *peeled)
{
struct packed_ref_iterator *iter =
(struct packed_ref_iterator *)ref_iterator;
return ref_iterator_peel(iter->iter0, peeled);
}
static int packed_ref_iterator_abort(struct ref_iterator *ref_iterator)
{
struct packed_ref_iterator *iter =
(struct packed_ref_iterator *)ref_iterator;
int ok = ITER_DONE;
if (iter->iter0)
ok = ref_iterator_abort(iter->iter0);
release_packed_ref_cache(iter->cache);
base_ref_iterator_free(ref_iterator);
return ok;
}
static struct ref_iterator_vtable packed_ref_iterator_vtable = {
packed_ref_iterator_advance,
packed_ref_iterator_peel,
packed_ref_iterator_abort
};
static struct ref_iterator *packed_ref_iterator_begin(
struct ref_store *ref_store,
const char *prefix, unsigned int flags)
{
struct packed_ref_store *refs;
struct packed_ref_iterator *iter;
struct ref_iterator *ref_iterator;
unsigned int required_flags = REF_STORE_READ;
if (!(flags & DO_FOR_EACH_INCLUDE_BROKEN))
required_flags |= REF_STORE_ODB;
refs = packed_downcast(ref_store, required_flags, "ref_iterator_begin");
iter = xcalloc(1, sizeof(*iter));
ref_iterator = &iter->base;
base_ref_iterator_init(ref_iterator, &packed_ref_iterator_vtable);
/*
* Note that get_packed_ref_cache() internally checks whether
* the packed-ref cache is up to date with what is on disk,
* and re-reads it if not.
*/
iter->cache = get_packed_ref_cache(refs);
acquire_packed_ref_cache(iter->cache);
iter->iter0 = cache_ref_iterator_begin(iter->cache->cache, prefix, 0);
iter->flags = flags;
return ref_iterator;
}
/*
* Write an entry to the packed-refs file for the specified refname.
* If peeled is non-NULL, write it as the entry's peeled value. On
* error, return a nonzero value and leave errno set at the value left
* by the failing call to `fprintf()`.
*/
static int write_packed_entry(FILE *fh, const char *refname,
const unsigned char *sha1,
const unsigned char *peeled)
{
if (fprintf(fh, "%s %s\n", sha1_to_hex(sha1), refname) < 0 ||
(peeled && fprintf(fh, "^%s\n", sha1_to_hex(peeled)) < 0))
return -1;
return 0;
}
int packed_refs_lock(struct ref_store *ref_store, int flags, struct strbuf *err)
{
struct packed_ref_store *refs =
packed_downcast(ref_store, REF_STORE_WRITE | REF_STORE_MAIN,
"packed_refs_lock");
static int timeout_configured = 0;
static int timeout_value = 1000;
struct packed_ref_cache *packed_ref_cache;
if (!timeout_configured) {
git_config_get_int("core.packedrefstimeout", &timeout_value);
timeout_configured = 1;
}
/*
* Note that we close the lockfile immediately because we
* don't write new content to it, but rather to a separate
* tempfile.
*/
if (hold_lock_file_for_update_timeout(
&refs->lock,
refs->path,
flags, timeout_value) < 0) {
unable_to_lock_message(refs->path, errno, err);
return -1;
}
if (close_lock_file(&refs->lock)) {
strbuf_addf(err, "unable to close %s: %s", refs->path, strerror(errno));
return -1;
}
/*
* Now that we hold the `packed-refs` lock, make sure that our
* cache matches the current version of the file. Normally
* `get_packed_ref_cache()` does that for us, but that
* function assumes that when the file is locked, any existing
* cache is still valid. We've just locked the file, but it
* might have changed the moment *before* we locked it.
*/
validate_packed_ref_cache(refs);
packed_ref_cache = get_packed_ref_cache(refs);
/* Increment the reference count to prevent it from being freed: */
acquire_packed_ref_cache(packed_ref_cache);
return 0;
}
void packed_refs_unlock(struct ref_store *ref_store)
{
struct packed_ref_store *refs = packed_downcast(
ref_store,
REF_STORE_READ | REF_STORE_WRITE,
"packed_refs_unlock");
if (!is_lock_file_locked(&refs->lock))
die("BUG: packed_refs_unlock() called when not locked");
rollback_lock_file(&refs->lock);
release_packed_ref_cache(refs->cache);
}
int packed_refs_is_locked(struct ref_store *ref_store)
{
struct packed_ref_store *refs = packed_downcast(
ref_store,
REF_STORE_READ | REF_STORE_WRITE,
"packed_refs_is_locked");
return is_lock_file_locked(&refs->lock);
}
/*
* The packed-refs header line that we write out. Perhaps other
* traits will be added later. The trailing space is required.
*/
static const char PACKED_REFS_HEADER[] =
"# pack-refs with: peeled fully-peeled \n";
/*
* Write the current version of the packed refs cache from memory to
* disk. The packed-refs file must already be locked for writing (see
* packed_refs_lock()). Return zero on success. On errors, rollback
* the lockfile, write an error message to `err`, and return a nonzero
* value.
*/
int commit_packed_refs(struct ref_store *ref_store, struct strbuf *err)
{
struct packed_ref_store *refs =
packed_downcast(ref_store, REF_STORE_WRITE | REF_STORE_MAIN,
"commit_packed_refs");
struct packed_ref_cache *packed_ref_cache =
get_packed_ref_cache(refs);
int ok;
int ret = -1;
struct strbuf sb = STRBUF_INIT;
FILE *out;
struct ref_iterator *iter;
char *packed_refs_path;
if (!is_lock_file_locked(&refs->lock))
die("BUG: commit_packed_refs() called when unlocked");
/*
* If packed-refs is a symlink, we want to overwrite the
* symlinked-to file, not the symlink itself. Also, put the
* staging file next to it:
*/
packed_refs_path = get_locked_file_path(&refs->lock);
strbuf_addf(&sb, "%s.new", packed_refs_path);
if (create_tempfile(&refs->tempfile, sb.buf) < 0) {
strbuf_addf(err, "unable to create file %s: %s",
sb.buf, strerror(errno));
strbuf_release(&sb);
goto out;
}
strbuf_release(&sb);
out = fdopen_tempfile(&refs->tempfile, "w");
if (!out) {
strbuf_addf(err, "unable to fdopen packed-refs tempfile: %s",
strerror(errno));
goto error;
}
if (fprintf(out, "%s", PACKED_REFS_HEADER) < 0) {
strbuf_addf(err, "error writing to %s: %s",
get_tempfile_path(&refs->tempfile), strerror(errno));
goto error;
}
iter = cache_ref_iterator_begin(packed_ref_cache->cache, NULL, 0);
while ((ok = ref_iterator_advance(iter)) == ITER_OK) {
struct object_id peeled;
int peel_error = ref_iterator_peel(iter, &peeled);
if (write_packed_entry(out, iter->refname, iter->oid->hash,
peel_error ? NULL : peeled.hash)) {
strbuf_addf(err, "error writing to %s: %s",
get_tempfile_path(&refs->tempfile),
strerror(errno));
ref_iterator_abort(iter);
goto error;
}
}
if (ok != ITER_DONE) {
strbuf_addf(err, "unable to rewrite packed-refs file: "
"error iterating over old contents");
goto error;
}
if (rename_tempfile(&refs->tempfile, packed_refs_path)) {
strbuf_addf(err, "error replacing %s: %s",
refs->path, strerror(errno));
goto out;
}
ret = 0;
goto out;
error:
delete_tempfile(&refs->tempfile);
out:
free(packed_refs_path);
return ret;
}
/*
* Rewrite the packed-refs file, omitting any refs listed in
* 'refnames'. On error, leave packed-refs unchanged, write an error
* message to 'err', and return a nonzero value. The packed refs lock
* must be held when calling this function; it will still be held when
* the function returns.
*
* The refs in 'refnames' needn't be sorted. `err` must not be NULL.
*/
int repack_without_refs(struct ref_store *ref_store,
struct string_list *refnames, struct strbuf *err)
{
struct packed_ref_store *refs =
packed_downcast(ref_store, REF_STORE_WRITE | REF_STORE_MAIN,
"repack_without_refs");
struct ref_dir *packed;
struct string_list_item *refname;
int needs_repacking = 0, removed = 0;
packed_assert_main_repository(refs, "repack_without_refs");
assert(err);
if (!is_lock_file_locked(&refs->lock))
die("BUG: repack_without_refs called without holding lock");
/* Look for a packed ref */
for_each_string_list_item(refname, refnames) {
if (get_packed_ref(refs, refname->string)) {
needs_repacking = 1;
break;
}
}
/* Avoid locking if we have nothing to do */
if (!needs_repacking)
return 0; /* no refname exists in packed refs */
packed = get_packed_refs(refs);
/* Remove refnames from the cache */
for_each_string_list_item(refname, refnames)
if (remove_entry_from_dir(packed, refname->string) != -1)
removed = 1;
if (!removed) {
/*
* All packed entries disappeared while we were
* acquiring the lock.
*/
clear_packed_ref_cache(refs);
return 0;
}
/* Write what remains */
return commit_packed_refs(&refs->base, err);
}
static int packed_init_db(struct ref_store *ref_store, struct strbuf *err)
{
/* Nothing to do. */
return 0;
}
static int packed_transaction_prepare(struct ref_store *ref_store,
struct ref_transaction *transaction,
struct strbuf *err)
{
die("BUG: not implemented yet");
}
static int packed_transaction_abort(struct ref_store *ref_store,
struct ref_transaction *transaction,
struct strbuf *err)
{
die("BUG: not implemented yet");
}
static int packed_transaction_finish(struct ref_store *ref_store,
struct ref_transaction *transaction,
struct strbuf *err)
{
die("BUG: not implemented yet");
}
static int packed_initial_transaction_commit(struct ref_store *ref_store,
struct ref_transaction *transaction,
struct strbuf *err)
{
return ref_transaction_commit(transaction, err);
}
static int packed_delete_refs(struct ref_store *ref_store, const char *msg,
struct string_list *refnames, unsigned int flags)
{
die("BUG: not implemented yet");
}
static int packed_pack_refs(struct ref_store *ref_store, unsigned int flags)
{
/*
* Packed refs are already packed. It might be that loose refs
* are packed *into* a packed refs store, but that is done by
* updating the packed references via a transaction.
*/
return 0;
}
static int packed_create_symref(struct ref_store *ref_store,
const char *refname, const char *target,
const char *logmsg)
{
die("BUG: packed reference store does not support symrefs");
}
static int packed_rename_ref(struct ref_store *ref_store,
const char *oldrefname, const char *newrefname,
const char *logmsg)
{
die("BUG: packed reference store does not support renaming references");
}
static struct ref_iterator *packed_reflog_iterator_begin(struct ref_store *ref_store)
{
return empty_ref_iterator_begin();
}
static int packed_for_each_reflog_ent(struct ref_store *ref_store,
const char *refname,
each_reflog_ent_fn fn, void *cb_data)
{
return 0;
}
static int packed_for_each_reflog_ent_reverse(struct ref_store *ref_store,
const char *refname,
each_reflog_ent_fn fn,
void *cb_data)
{
return 0;
}
static int packed_reflog_exists(struct ref_store *ref_store,
const char *refname)
{
return 0;
}
static int packed_create_reflog(struct ref_store *ref_store,
const char *refname, int force_create,
struct strbuf *err)
{
die("BUG: packed reference store does not support reflogs");
}
static int packed_delete_reflog(struct ref_store *ref_store,
const char *refname)
{
return 0;
}
static int packed_reflog_expire(struct ref_store *ref_store,
const char *refname, const unsigned char *sha1,
unsigned int flags,
reflog_expiry_prepare_fn prepare_fn,
reflog_expiry_should_prune_fn should_prune_fn,
reflog_expiry_cleanup_fn cleanup_fn,
void *policy_cb_data)
{
return 0;
}
struct ref_storage_be refs_be_packed = {
NULL,
"packed",
packed_ref_store_create,
packed_init_db,
packed_transaction_prepare,
packed_transaction_finish,
packed_transaction_abort,
packed_initial_transaction_commit,
packed_pack_refs,
packed_peel_ref,
packed_create_symref,
packed_delete_refs,
packed_rename_ref,
packed_ref_iterator_begin,
packed_read_raw_ref,
packed_reflog_iterator_begin,
packed_for_each_reflog_ent,
packed_for_each_reflog_ent_reverse,
packed_reflog_exists,
packed_create_reflog,
packed_delete_reflog,
packed_reflog_expire
};

25
refs/packed-backend.h Normal file
View File

@ -0,0 +1,25 @@
#ifndef REFS_PACKED_BACKEND_H
#define REFS_PACKED_BACKEND_H
struct ref_store *packed_ref_store_create(const char *path,
unsigned int store_flags);
/*
* Lock the packed-refs file for writing. Flags is passed to
* hold_lock_file_for_update(). Return 0 on success. On errors, write
* an error message to `err` and return a nonzero value.
*/
int packed_refs_lock(struct ref_store *ref_store, int flags, struct strbuf *err);
void packed_refs_unlock(struct ref_store *ref_store);
int packed_refs_is_locked(struct ref_store *ref_store);
void add_packed_ref(struct ref_store *ref_store,
const char *refname, const struct object_id *oid);
int commit_packed_refs(struct ref_store *ref_store, struct strbuf *err);
int repack_without_refs(struct ref_store *ref_store,
struct string_list *refnames, struct strbuf *err);
#endif /* REFS_PACKED_BACKEND_H */

10
refs/refs-internal.h
View File

@ -77,6 +77,15 @@
*/
int refname_is_safe(const char *refname);
/*
* Helper function: return true if refname, which has the specified
* oid and flags, can be resolved to an object in the database. If the
* referred-to object does not exist, emit a warning and return false.
*/
int ref_resolves_to_object(const char *refname,
const struct object_id *oid,
unsigned int flags);
enum peel_status {
/* object was peeled successfully: */
PEEL_PEELED = 0,
@ -655,6 +664,7 @@ struct ref_storage_be {
};
extern struct ref_storage_be refs_be_files;
extern struct ref_storage_be refs_be_packed;
/*
* A representation of the reference store for the main repository or

42
t/t1408-packed-refs.sh Executable file
View File

@ -0,0 +1,42 @@
#!/bin/sh
test_description='packed-refs entries are covered by loose refs'
. ./test-lib.sh
test_expect_success setup '
test_tick &&
git commit --allow-empty -m one &&
one=$(git rev-parse HEAD) &&
git for-each-ref >actual &&
echo "$one commit refs/heads/master" >expect &&
test_cmp expect actual &&
git pack-refs --all &&
git for-each-ref >actual &&
echo "$one commit refs/heads/master" >expect &&
test_cmp expect actual &&
git checkout --orphan another &&
test_tick &&
git commit --allow-empty -m two &&
two=$(git rev-parse HEAD) &&
git checkout -B master &&
git branch -D another &&
git for-each-ref >actual &&
echo "$two commit refs/heads/master" >expect &&
test_cmp expect actual &&
git reflog expire --expire=now --all &&
git prune &&
git tag -m v1.0 v1.0 master
'
test_expect_success 'no error from stale entry in packed-refs' '
git describe master >actual 2>&1 &&
echo "v1.0" >expect &&
test_cmp expect actual
'
test_done

42
t/t3210-pack-refs.sh
View File

@ -194,6 +194,33 @@ test_expect_success 'notice d/f conflict with existing ref' '
test_must_fail git branch foo/bar/baz/lots/of/extra/components
'
test_expect_success 'reject packed-refs with unterminated line' '
cp .git/packed-refs .git/packed-refs.bak &&
test_when_finished "mv .git/packed-refs.bak .git/packed-refs" &&
printf "%s" "$HEAD refs/zzzzz" >>.git/packed-refs &&
echo "fatal: unterminated line in .git/packed-refs: $HEAD refs/zzzzz" >expected_err &&
test_must_fail git for-each-ref >out 2>err &&
test_cmp expected_err err
'
test_expect_success 'reject packed-refs containing junk' '
cp .git/packed-refs .git/packed-refs.bak &&
test_when_finished "mv .git/packed-refs.bak .git/packed-refs" &&
printf "%s\n" "bogus content" >>.git/packed-refs &&
echo "fatal: unexpected line in .git/packed-refs: bogus content" >expected_err &&
test_must_fail git for-each-ref >out 2>err &&
test_cmp expected_err err
'
test_expect_success 'reject packed-refs with a short SHA-1' '
cp .git/packed-refs .git/packed-refs.bak &&
test_when_finished "mv .git/packed-refs.bak .git/packed-refs" &&
printf "%.7s %s\n" $HEAD refs/zzzzz >>.git/packed-refs &&
printf "fatal: unexpected line in .git/packed-refs: %.7s %s\n" $HEAD refs/zzzzz >expected_err &&
test_must_fail git for-each-ref >out 2>err &&
test_cmp expected_err err
'
test_expect_success 'timeout if packed-refs.lock exists' '
LOCK=.git/packed-refs.lock &&
>"$LOCK" &&
@ -211,4 +238,19 @@ test_expect_success 'retry acquiring packed-refs.lock' '
git -c core.packedrefstimeout=3000 pack-refs --all --prune
'
test_expect_success SYMLINKS 'pack symlinked packed-refs' '
# First make sure that symlinking works when reading:
git update-ref refs/heads/loosy refs/heads/master &&
git for-each-ref >all-refs-before &&
mv .git/packed-refs .git/my-deviant-packed-refs &&
ln -s my-deviant-packed-refs .git/packed-refs &&
git for-each-ref >all-refs-linked &&
test_cmp all-refs-before all-refs-linked &&
git pack-refs --all --prune &&
git for-each-ref >all-refs-packed &&
test_cmp all-refs-before all-refs-packed &&
test -h .git/packed-refs &&
test "$(readlink .git/packed-refs)" = "my-deviant-packed-refs"
'
test_done