#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"
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;
-};
-
-/*
- * A container for `packed-refs`-related data. It is not (yet) a
- * `ref_store`.
- */
-struct packed_ref_store {
- 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;
-};
-
-static struct packed_ref_store *packed_ref_store_create(
- const char *path, unsigned int store_flags)
-{
- struct packed_ref_store *refs = xcalloc(1, sizeof(*refs));
-
- refs->store_flags = store_flags;
- refs->path = xstrdup(path);
- return refs;
-}
-
/*
* Future: need to be in "struct repository"
* when doing a full libification.
struct ref_cache *loose;
- struct packed_ref_store *packed_ref_store;
+ 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 packed_ref_store *refs)
-{
- if (refs->cache) {
- struct packed_ref_cache *cache = refs->cache;
-
- if (is_lock_file_locked(&refs->lock))
- die("BUG: packed-ref cache cleared while locked");
- refs->cache = NULL;
- release_packed_ref_cache(cache);
- }
-}
-
static void clear_loose_ref_cache(struct files_ref_store *refs)
{
if (refs->loose) {
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 void files_reflog_path(struct files_ref_store *refs,
struct strbuf *sb,
const char *refname)
}
}
-/*
- * 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 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 = refs->packed_ref_store->path;
-
- if (!is_lock_file_locked(&refs->packed_ref_store->lock))
- validate_packed_ref_cache(refs->packed_ref_store);
-
- if (!refs->packed_ref_store->cache)
- refs->packed_ref_store->cache = read_packed_refs(packed_refs_file);
-
- return refs->packed_ref_store->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 files_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 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 ref_dir *packed_refs;
- struct ref_entry *packed_entry;
-
- if (!is_lock_file_locked(&refs->packed_ref_store->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);
- }
-}
-
/*
* Read the loose references from the namespace dirname into dir
* (without recursing). dirname must end with '/'. dir must be the
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)
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;
}
* 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;
}
* 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);
}
struct files_ref_iterator {
struct ref_iterator base;
- struct packed_ref_cache *packed_ref_cache;
struct ref_iterator *iter0;
unsigned int flags;
};
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;
}
* (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;
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_ref_store->lock,
- refs->packed_ref_store->path,
- 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_store);
-
- 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_ref_store->lock))
- die("BUG: packed-refs not locked");
-
- out = fdopen_lock_file(&refs->packed_ref_store->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_ref_store->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_ref_store->lock))
- die("BUG: packed-refs not locked");
- rollback_lock_file(&refs->packed_ref_store->lock);
- release_packed_ref_cache(packed_ref_cache);
- clear_packed_ref_cache(refs->packed_ref_store);
-}
-
struct ref_to_prune {
struct ref_to_prune *next;
unsigned char sha1[20];
int ok;
struct ref_to_prune *refs_to_prune = NULL;
- lock_packed_refs(refs, LOCK_DIE_ON_ERROR);
+ lock_packed_refs(refs->packed_ref_store, LOCK_DIE_ON_ERROR);
iter = cache_ref_iterator_begin(get_loose_ref_cache(refs), NULL, 0);
while ((ok = ref_iterator_advance(iter)) == ITER_OK) {
* we don't copy the peeled status, because we want it
* to be re-peeled.
*/
- add_packed_ref(refs, iter->refname, iter->oid);
+ add_packed_ref(refs->packed_ref_store, iter->refname, iter->oid);
/* Schedule the loose reference for pruning if requested. */
if ((flags & PACK_REFS_PRUNE)) {
if (ok != ITER_DONE)
die("error while iterating over references");
- if (commit_packed_refs(refs))
+ if (commit_packed_refs(refs->packed_ref_store))
die_errno("unable to overwrite old ref-pack file");
prune_refs(refs, refs_to_prune);
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(refs->packed_ref_store->path, 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)
{
if (!refnames->nr)
return 0;
- result = repack_without_refs(refs, refnames, &err);
+ result = repack_without_refs(refs->packed_ref_store, refnames, &err);
if (result) {
/*
* If we failed to rewrite the packed-refs file, then
}
}
- if (repack_without_refs(refs, &refs_to_delete, err)) {
+ if (repack_without_refs(refs->packed_ref_store, &refs_to_delete, err)) {
ret = TRANSACTION_GENERIC_ERROR;
goto cleanup;
}
}
}
- if (lock_packed_refs(refs, 0)) {
+ if (lock_packed_refs(refs->packed_ref_store, 0)) {
strbuf_addf(err, "unable to lock packed-refs file: %s",
strerror(errno));
ret = TRANSACTION_GENERIC_ERROR;
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)) {
+ if (commit_packed_refs(refs->packed_ref_store)) {
strbuf_addf(err, "unable to commit packed-refs file: %s",
strerror(errno));
ret = TRANSACTION_GENERIC_ERROR;