diff options
Diffstat (limited to 'refs')
| -rw-r--r-- | refs/files-backend.c | 1604 | ||||
| -rw-r--r-- | refs/iterator.c | 65 | ||||
| -rw-r--r-- | refs/packed-backend.c | 1656 | ||||
| -rw-r--r-- | refs/packed-backend.h | 35 | ||||
| -rw-r--r-- | refs/ref-cache.c | 160 | ||||
| -rw-r--r-- | refs/ref-cache.h | 41 | ||||
| -rw-r--r-- | refs/refs-internal.h | 210 |
7 files changed, 2652 insertions, 1119 deletions
diff --git a/refs/files-backend.c b/refs/files-backend.c index 83ea080e01..bec8e30e9e 100644 --- a/refs/files-backend.c +++ b/refs/files-backend.c @@ -1,59 +1,64 @@ #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 "../dir-iterator.h" #include "../lockfile.h" #include "../object.h" #include "../dir.h" -struct ref_lock { - char *ref_name; - struct lock_file *lk; - struct object_id old_oid; -}; +/* + * This backend uses the following flags in `ref_update::flags` for + * internal bookkeeping purposes. Their numerical values must not + * conflict with REF_NO_DEREF, REF_FORCE_CREATE_REFLOG, REF_HAVE_NEW, + * REF_HAVE_OLD, or REF_IS_PRUNING, which are also stored in + * `ref_update::flags`. + */ /* - * 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. + * Used as a flag in ref_update::flags when a loose ref is being + * pruned. This flag must only be used when REF_NO_DEREF is set. */ -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; -} +#define REF_IS_PRUNING (1 << 4) -struct packed_ref_cache { - struct ref_cache *cache; +/* + * Flag passed to lock_ref_sha1_basic() telling it to tolerate broken + * refs (i.e., because the reference is about to be deleted anyway). + */ +#define REF_DELETING (1 << 5) - /* - * 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; +/* + * Used as a flag in ref_update::flags when the lockfile needs to be + * committed. + */ +#define REF_NEEDS_COMMIT (1 << 6) - /* - * Iff the packed-refs file associated with this instance is - * currently locked for writing, this points at the associated - * lock (which is owned by somebody else). The referrer count - * is also incremented when the file is locked and decremented - * when it is unlocked. - */ - struct lock_file *lock; +/* + * Used as a flag in ref_update::flags when we want to log a ref + * update but not actually perform it. This is used when a symbolic + * ref update is split up. + */ +#define REF_LOG_ONLY (1 << 7) + +/* + * Used as a flag in ref_update::flags when the ref_update was via an + * update to HEAD. + */ +#define REF_UPDATE_VIA_HEAD (1 << 8) - /* The metadata from when this packed-refs cache was read */ - struct stat_validity validity; +/* + * Used as a flag in ref_update::flags when the loose reference has + * been deleted. + */ +#define REF_DELETED_LOOSE (1 << 9) + +struct ref_lock { + char *ref_name; + struct lock_file lk; + struct object_id old_oid; }; /* @@ -66,50 +71,11 @@ 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 main packed-refs file: */ -static struct lock_file packlock; -/* - * 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 (packed_refs->lock) - die("internal error: packed-ref cache cleared while locked"); - refs->packed = NULL; - release_packed_ref_cache(packed_refs); - } -} + struct ref_store *packed_ref_store; +}; static void clear_loose_ref_cache(struct files_ref_store *refs) { @@ -137,7 +103,8 @@ 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; } @@ -180,152 +147,10 @@ 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, unsigned char *sha1) -{ - const char *ref; - - /* - * 42: the answer to everything. - * - * In this case, it happens to be the answer to - * 40 (length of sha1 hex representation) - * +1 (space in between hex and name) - * +1 (newline at the end of the line) - */ - if (line->len <= 42) - return NULL; - - if (get_sha1_hex(line->buf, sha1) < 0) - return NULL; - if (!isspace(line->buf[40])) - return NULL; - - ref = line->buf + 41; - if (isspace(*ref)) - return NULL; - - if (line->buf[line->len - 1] != '\n') - return NULL; - line->buf[--line->len] = 0; - - return ref; -} - -/* - * Read f, which is a packed-refs file, into dir. - * - * 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 void read_packed_refs(FILE *f, struct ref_dir *dir) -{ - struct ref_entry *last = NULL; - struct strbuf line = STRBUF_INIT; - enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled = PEELED_NONE; - - while (strbuf_getwholeline(&line, f, '\n') != EOF) { - unsigned char sha1[20]; - 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, sha1); - 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); - hashclr(sha1); - flag |= REF_BAD_NAME | REF_ISBROKEN; - } - last = create_ref_entry(refname, sha1, flag, 0); - 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_sha1_hex(line.buf + 1, sha1)) { - hashcpy(last->u.value.peeled.hash, sha1); - /* - * Regardless of what the file header said, - * we definitely know the value of *this* - * reference: - */ - last->flag |= REF_KNOWS_PEELED; - } - } - - strbuf_release(&line); -} - -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) { - if (!refname) { - /* - * FIXME: of course this is wrong in multi worktree - * setting. To be fixed real soon. - */ - strbuf_addf(sb, "%s/logs", refs->gitcommondir); - return; - } - switch (ref_type(refname)) { case REF_TYPE_PER_WORKTREE: case REF_TYPE_PSEUDOREF: @@ -359,62 +184,6 @@ static void files_ref_path(struct files_ref_store *refs, } /* - * Get the packed_ref_cache for the specified files_ref_store, - * creating it if necessary. - */ -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 (refs->packed && - !stat_validity_check(&refs->packed->validity, packed_refs_file)) - clear_packed_ref_cache(refs); - - if (!refs->packed) { - FILE *f; - - refs->packed = xcalloc(1, sizeof(*refs->packed)); - acquire_packed_ref_cache(refs->packed); - refs->packed->cache = create_ref_cache(&refs->base, NULL); - refs->packed->cache->root->flag &= ~REF_INCOMPLETE; - f = fopen(packed_refs_file, "r"); - if (f) { - stat_validity_update(&refs->packed->validity, fileno(f)); - read_packed_refs(f, get_ref_dir(refs->packed->cache->root)); - fclose(f); - } - } - 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 unsigned char *sha1) -{ - struct packed_ref_cache *packed_ref_cache = get_packed_ref_cache(refs); - - if (!packed_ref_cache->lock) - die("internal error: packed refs not locked"); - add_ref_entry(get_packed_ref_dir(packed_ref_cache), - create_ref_entry(refname, sha1, REF_ISPACKED, 1)); -} - -/* * Read the loose references from the namespace dirname into dir * (without recursing). dirname must end with '/'. dir must be the * directory entry corresponding to dirname. @@ -444,7 +213,7 @@ static void loose_fill_ref_dir(struct ref_store *ref_store, strbuf_add(&refname, dirname, dirnamelen); while ((de = readdir(d)) != NULL) { - unsigned char sha1[20]; + struct object_id oid; struct stat st; int flag; @@ -465,13 +234,13 @@ static void loose_fill_ref_dir(struct ref_store *ref_store, if (!refs_resolve_ref_unsafe(&refs->base, refname.buf, RESOLVE_REF_READING, - sha1, &flag)) { - hashclr(sha1); + &oid, &flag)) { + oidclr(&oid); flag |= REF_ISBROKEN; - } else if (is_null_sha1(sha1)) { + } else if (is_null_oid(&oid)) { /* * It is so astronomically unlikely - * that NULL_SHA1 is the SHA-1 of an + * that null_oid is the OID of an * actual object that we consider its * appearance in a loose reference * file to be repo corruption @@ -484,11 +253,11 @@ static void loose_fill_ref_dir(struct ref_store *ref_store, REFNAME_ALLOW_ONELEVEL)) { if (!refname_is_safe(refname.buf)) die("loose refname is dangerous: %s", refname.buf); - hashclr(sha1); + oidclr(&oid); flag |= REF_BAD_NAME | REF_ISBROKEN; } add_entry_to_dir(dir, - create_ref_entry(refname.buf, sha1, flag, 0)); + create_ref_entry(refname.buf, &oid, flag)); } strbuf_setlen(&refname, dirnamelen); strbuf_setlen(&path, path_baselen); @@ -536,41 +305,8 @@ 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, + const char *refname, struct object_id *oid, struct strbuf *referent, unsigned int *type) { struct files_ref_store *refs = @@ -579,6 +315,7 @@ static int files_read_raw_ref(struct ref_store *ref_store, struct strbuf sb_path = STRBUF_INIT; const char *path; const char *buf; + const char *p; struct stat st; int fd; int ret = -1; @@ -612,7 +349,8 @@ 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, + oid, referent, type)) { errno = ENOENT; goto out; } @@ -651,7 +389,8 @@ 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, + oid, referent, type)) { errno = EISDIR; goto out; } @@ -697,8 +436,8 @@ stat_ref: * Please note that FETCH_HEAD has additional * data after the sha. */ - if (get_sha1_hex(buf, sha1) || - (buf[40] != '\0' && !isspace(buf[40]))) { + if (parse_oid_hex(buf, oid, &p) || + (*p != '\0' && !isspace(*p))) { *type |= REF_ISBROKEN; errno = EINVAL; goto out; @@ -716,9 +455,7 @@ out: static void unlock_ref(struct ref_lock *lock) { - /* Do not free lock->lk -- atexit() still looks at them */ - if (lock->lk) - rollback_lock_file(lock->lk); + rollback_lock_file(&lock->lk); free(lock->ref_name); free(lock); } @@ -736,7 +473,7 @@ static void unlock_ref(struct ref_lock *lock) * are passed to refs_verify_refname_available() for this check. * * If mustexist is not set and the reference is not found or is - * broken, lock the reference anyway but clear sha1. + * broken, lock the reference anyway but clear old_oid. * * Return 0 on success. On failure, write an error message to err and * return TRANSACTION_NAME_CONFLICT or TRANSACTION_GENERIC_ERROR. @@ -832,10 +569,9 @@ retry: goto error_return; } - if (!lock->lk) - lock->lk = xcalloc(1, sizeof(struct lock_file)); - - if (hold_lock_file_for_update(lock->lk, ref_file.buf, LOCK_NO_DEREF) < 0) { + if (hold_lock_file_for_update_timeout( + &lock->lk, ref_file.buf, LOCK_NO_DEREF, + get_files_ref_lock_timeout_ms()) < 0) { if (errno == ENOENT && --attempts_remaining > 0) { /* * Maybe somebody just deleted one of the @@ -855,7 +591,7 @@ retry: */ if (files_read_raw_ref(&refs->base, refname, - lock->old_oid.hash, referent, type)) { + &lock->old_oid, referent, type)) { if (errno == ENOENT) { if (mustexist) { /* Garden variety missing reference. */ @@ -930,11 +666,11 @@ 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; } @@ -951,53 +687,9 @@ out: return ret; } -static int files_peel_ref(struct ref_store *ref_store, - const char *refname, unsigned char *sha1) -{ - struct files_ref_store *refs = - files_downcast(ref_store, REF_STORE_READ | REF_STORE_ODB, - "peel_ref"); - int flag; - unsigned char base[20]; - - if (current_ref_iter && current_ref_iter->refname == refname) { - struct object_id peeled; - - if (ref_iterator_peel(current_ref_iter, &peeled)) - return -1; - hashcpy(sha1, peeled.hash); - return 0; - } - - if (refs_read_ref_full(ref_store, refname, - RESOLVE_REF_READING, base, &flag)) - return -1; - - /* - * If the reference is packed, read its ref_entry from the - * cache in the hope that we already know its peeled value. - * We only try this optimization on packed references because - * (a) forcing the filling of the loose reference cache could - * 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; - } - } - - 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; }; @@ -1050,7 +742,6 @@ 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; } @@ -1066,22 +757,15 @@ static struct ref_iterator *files_ref_iterator_begin( const char *prefix, unsigned int flags) { struct files_ref_store *refs; - struct ref_iterator *loose_iter, *packed_iter; + struct ref_iterator *loose_iter, *packed_iter, *overlay_iter; struct files_ref_iterator *iter; struct ref_iterator *ref_iterator; + unsigned int required_flags = REF_STORE_READ; - if (ref_paranoia < 0) - ref_paranoia = git_env_bool("GIT_REF_PARANOIA", 0); - if (ref_paranoia) - flags |= DO_FOR_EACH_INCLUDE_BROKEN; + if (!(flags & DO_FOR_EACH_INCLUDE_BROKEN)) + required_flags |= REF_STORE_ODB; - refs = files_downcast(ref_store, - REF_STORE_READ | (ref_paranoia ? 0 : REF_STORE_ODB), - "ref_iterator_begin"); - - iter = xcalloc(1, sizeof(*iter)); - ref_iterator = &iter->base; - base_ref_iterator_init(ref_iterator, &files_ref_iterator_vtable); + refs = files_downcast(ref_store, required_flags, "ref_iterator_begin"); /* * We must make sure that all loose refs are read before @@ -1095,41 +779,57 @@ 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); + + overlay_iter = overlay_ref_iterator_begin(loose_iter, packed_iter); - iter->iter0 = overlay_ref_iterator_begin(loose_iter, packed_iter); + iter = xcalloc(1, sizeof(*iter)); + ref_iterator = &iter->base; + base_ref_iterator_init(ref_iterator, &files_ref_iterator_vtable, + overlay_iter->ordered); + iter->iter0 = overlay_iter; iter->flags = flags; return ref_iterator; } /* - * Verify that the reference locked by lock has the value old_sha1. - * Fail if the reference doesn't exist and mustexist is set. Return 0 - * on success. On error, write an error message to err, set errno, and - * return a negative value. + * Verify that the reference locked by lock has the value old_oid + * (unless it is NULL). Fail if the reference doesn't exist and + * mustexist is set. Return 0 on success. On error, write an error + * message to err, set errno, and return a negative value. */ static int verify_lock(struct ref_store *ref_store, struct ref_lock *lock, - const unsigned char *old_sha1, int mustexist, + const struct object_id *old_oid, int mustexist, struct strbuf *err) { assert(err); if (refs_read_ref_full(ref_store, lock->ref_name, mustexist ? RESOLVE_REF_READING : 0, - lock->old_oid.hash, NULL)) { - if (old_sha1) { + &lock->old_oid, NULL)) { + if (old_oid) { int save_errno = errno; strbuf_addf(err, "can't verify ref '%s'", lock->ref_name); errno = save_errno; @@ -1139,11 +839,11 @@ static int verify_lock(struct ref_store *ref_store, struct ref_lock *lock, return 0; } } - if (old_sha1 && hashcmp(lock->old_oid.hash, old_sha1)) { + if (old_oid && oidcmp(&lock->old_oid, old_oid)) { strbuf_addf(err, "ref '%s' is at %s but expected %s", lock->ref_name, oid_to_hex(&lock->old_oid), - sha1_to_hex(old_sha1)); + oid_to_hex(old_oid)); errno = EBUSY; return -1; } @@ -1164,29 +864,31 @@ static int create_reflock(const char *path, void *cb) { struct lock_file *lk = cb; - return hold_lock_file_for_update(lk, path, LOCK_NO_DEREF) < 0 ? -1 : 0; + return hold_lock_file_for_update_timeout( + lk, path, LOCK_NO_DEREF, + get_files_ref_lock_timeout_ms()) < 0 ? -1 : 0; } /* * Locks a ref returning the lock on success and NULL on failure. * On failure errno is set to something meaningful. */ -static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs, - const char *refname, - const unsigned char *old_sha1, - const struct string_list *extras, - const struct string_list *skip, - unsigned int flags, int *type, - struct strbuf *err) +static struct ref_lock *lock_ref_oid_basic(struct files_ref_store *refs, + const char *refname, + const struct object_id *old_oid, + const struct string_list *extras, + const struct string_list *skip, + unsigned int flags, int *type, + struct strbuf *err) { struct strbuf ref_file = STRBUF_INIT; struct ref_lock *lock; int last_errno = 0; - int mustexist = (old_sha1 && !is_null_sha1(old_sha1)); + int mustexist = (old_oid && !is_null_oid(old_oid)); int resolve_flags = RESOLVE_REF_NO_RECURSE; int resolved; - files_assert_main_repository(refs, "lock_ref_sha1_basic"); + files_assert_main_repository(refs, "lock_ref_oid_basic"); assert(err); lock = xcalloc(1, sizeof(struct ref_lock)); @@ -1199,7 +901,7 @@ static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs, files_ref_path(refs, &ref_file, refname); resolved = !!refs_resolve_ref_unsafe(&refs->base, refname, resolve_flags, - lock->old_oid.hash, type); + &lock->old_oid, type); if (!resolved && errno == EISDIR) { /* * we are trying to lock foo but we used to @@ -1218,7 +920,7 @@ static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs, } resolved = !!refs_resolve_ref_unsafe(&refs->base, refname, resolve_flags, - lock->old_oid.hash, type); + &lock->old_oid, type); } if (!resolved) { last_errno = errno; @@ -1238,23 +940,21 @@ 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; } - lock->lk = xcalloc(1, sizeof(struct lock_file)); - lock->ref_name = xstrdup(refname); - if (raceproof_create_file(ref_file.buf, create_reflock, lock->lk)) { + if (raceproof_create_file(ref_file.buf, create_reflock, &lock->lk)) { last_errno = errno; unable_to_lock_message(ref_file.buf, errno, err); goto error_return; } - if (verify_lock(&refs->base, lock, old_sha1, mustexist, err)) { + if (verify_lock(&refs->base, lock, old_oid, mustexist, err)) { last_errno = errno; goto error_return; } @@ -1270,125 +970,9 @@ 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( - &packlock, files_packed_refs_path(refs), - flags, timeout_value) < 0) - return -1; - /* - * Get the current packed-refs while holding the lock. If the - * packed-refs file has been modified since we last read it, - * this will automatically invalidate the cache and re-read - * the packed-refs file. - */ - packed_ref_cache = get_packed_ref_cache(refs); - packed_ref_cache->lock = &packlock; - /* 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 (!packed_ref_cache->lock) - die("internal error: packed-refs not locked"); - - out = fdopen_lock_file(packed_ref_cache->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(packed_ref_cache->lock)) { - save_errno = errno; - error = -1; - } - packed_ref_cache->lock = NULL; - 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 (!packed_ref_cache->lock) - die("internal error: packed-refs not locked"); - rollback_lock_file(packed_ref_cache->lock); - packed_ref_cache->lock = NULL; - 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]; + struct object_id oid; char name[FLEX_ARRAY]; }; @@ -1450,44 +1034,87 @@ static void prune_ref(struct files_ref_store *refs, struct ref_to_prune *r) { struct ref_transaction *transaction; struct strbuf err = STRBUF_INIT; + int ret = -1; if (check_refname_format(r->name, 0)) return; transaction = ref_store_transaction_begin(&refs->base, &err); - if (!transaction || - ref_transaction_delete(transaction, r->name, r->sha1, - REF_ISPRUNING | REF_NODEREF, NULL, &err) || - ref_transaction_commit(transaction, &err)) { - ref_transaction_free(transaction); + if (!transaction) + goto cleanup; + ref_transaction_add_update( + transaction, r->name, + REF_NO_DEREF | REF_HAVE_NEW | REF_HAVE_OLD | REF_IS_PRUNING, + &null_oid, &r->oid, NULL); + if (ref_transaction_commit(transaction, &err)) + goto cleanup; + + ret = 0; + +cleanup: + if (ret) error("%s", err.buf); - strbuf_release(&err); - return; - } - ref_transaction_free(transaction); strbuf_release(&err); + ref_transaction_free(transaction); + return; } -static void prune_refs(struct files_ref_store *refs, struct ref_to_prune *r) +/* + * Prune the loose versions of the references in the linked list + * `*refs_to_prune`, freeing the entries in the list as we go. + */ +static void prune_refs(struct files_ref_store *refs, struct ref_to_prune **refs_to_prune) { - while (r) { + while (*refs_to_prune) { + struct ref_to_prune *r = *refs_to_prune; + *refs_to_prune = r->next; prune_ref(refs, r); - r = r->next; + free(r); } } +/* + * Return true if the specified reference should be packed. + */ +static int should_pack_ref(const char *refname, + const struct object_id *oid, unsigned int ref_flags, + unsigned int pack_flags) +{ + /* Do not pack per-worktree refs: */ + if (ref_type(refname) != REF_TYPE_NORMAL) + return 0; + + /* Do not pack non-tags unless PACK_REFS_ALL is set: */ + if (!(pack_flags & PACK_REFS_ALL) && !starts_with(refname, "refs/tags/")) + return 0; + + /* Do not pack symbolic refs: */ + if (ref_flags & REF_ISSYMREF) + return 0; + + /* Do not pack broken refs: */ + if (!ref_resolves_to_object(refname, oid, ref_flags)) + return 0; + + return 1; +} + static int files_pack_refs(struct ref_store *ref_store, unsigned int flags) { struct files_ref_store *refs = 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; + struct ref_transaction *transaction; - lock_packed_refs(refs, LOCK_DIE_ON_ERROR); - packed_refs = get_packed_refs(refs); + transaction = ref_store_transaction_begin(refs->packed_ref_store, &err); + if (!transaction) + return -1; + + 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) { @@ -1496,47 +1123,25 @@ 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; - int is_tag_ref = starts_with(iter->refname, "refs/tags/"); - - /* Do not pack per-worktree refs: */ - if (ref_type(iter->refname) != REF_TYPE_NORMAL) - continue; - - /* ALWAYS pack tags */ - if (!(flags & PACK_REFS_ALL) && !is_tag_ref) - continue; - - /* Do not pack symbolic or broken refs: */ - if (iter->flags & REF_ISSYMREF) - continue; - - if (!ref_resolves_to_object(iter->refname, iter->oid, iter->flags)) + if (!should_pack_ref(iter->refname, iter->oid, iter->flags, + flags)) continue; /* - * Create an entry in the packed-refs cache equivalent - * to the one from the loose ref cache, except that - * we don't copy the peeled status, because we want it - * to be re-peeled. + * Add a reference creation for this reference to the + * packed-refs transaction: */ - 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->hash, - REF_ISPACKED, 0); - add_ref_entry(packed_refs, packed_entry); - } - oidclr(&packed_entry->u.value.peeled); + if (ref_transaction_update(transaction, iter->refname, + iter->oid, NULL, + REF_NO_DEREF, NULL, &err)) + die("failure preparing to create packed reference %s: %s", + iter->refname, err.buf); /* Schedule the loose reference for pruning if requested. */ if ((flags & PACK_REFS_PRUNE)) { struct ref_to_prune *n; FLEX_ALLOC_STR(n, name, iter->refname); - hashcpy(n->sha1, iter->oid->hash); + oidcpy(&n->oid, iter->oid); n->next = refs_to_prune; refs_to_prune = n; } @@ -1544,70 +1149,19 @@ 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"); - - 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; - } - } + if (ref_transaction_commit(transaction, &err)) + die("unable to write new packed-refs: %s", err.buf); - /* 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); + ref_transaction_free(transaction); - /* 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; - } + packed_refs_unlock(refs->packed_ref_store); - /* 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; + prune_refs(refs, &refs_to_prune); + strbuf_release(&err); + return 0; } -static int files_delete_refs(struct ref_store *ref_store, +static int files_delete_refs(struct ref_store *ref_store, const char *msg, struct string_list *refnames, unsigned int flags) { struct files_ref_store *refs = @@ -1618,34 +1172,41 @@ static int files_delete_refs(struct ref_store *ref_store, 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 (refs_delete_refs(refs->packed_ref_store, msg, refnames, flags)) { + 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; - if (refs_delete_ref(&refs->base, NULL, refname, NULL, flags)) + if (refs_delete_ref(&refs->base, msg, refname, NULL, flags)) 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; } /* @@ -1709,19 +1270,19 @@ static int rename_tmp_log(struct files_ref_store *refs, const char *newrefname) } static int write_ref_to_lockfile(struct ref_lock *lock, - const unsigned char *sha1, struct strbuf *err); + const struct object_id *oid, struct strbuf *err); static int commit_ref_update(struct files_ref_store *refs, struct ref_lock *lock, - const unsigned char *sha1, const char *logmsg, + const struct object_id *oid, const char *logmsg, struct strbuf *err); -static int files_rename_ref(struct ref_store *ref_store, +static int files_copy_or_rename_ref(struct ref_store *ref_store, const char *oldrefname, const char *newrefname, - const char *logmsg) + const char *logmsg, int copy) { struct files_ref_store *refs = files_downcast(ref_store, REF_STORE_WRITE, "rename_ref"); - unsigned char sha1[20], orig_sha1[20]; + struct object_id oid, orig_oid; int flag = 0, logmoved = 0; struct ref_lock *lock; struct stat loginfo; @@ -1743,14 +1304,18 @@ static int files_rename_ref(struct ref_store *ref_store, if (!refs_resolve_ref_unsafe(&refs->base, oldrefname, RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE, - orig_sha1, &flag)) { + &orig_oid, &flag)) { ret = error("refname %s not found", oldrefname); goto out; } if (flag & REF_ISSYMREF) { - ret = error("refname %s is a symbolic ref, renaming it is not supported", - oldrefname); + if (copy) + ret = error("refname %s is a symbolic ref, copying it is not supported", + oldrefname); + else + ret = error("refname %s is a symbolic ref, renaming it is not supported", + oldrefname); goto out; } if (!refs_rename_ref_available(&refs->base, oldrefname, newrefname)) { @@ -1758,30 +1323,36 @@ static int files_rename_ref(struct ref_store *ref_store, goto out; } - if (log && rename(sb_oldref.buf, tmp_renamed_log.buf)) { + if (!copy && log && rename(sb_oldref.buf, tmp_renamed_log.buf)) { ret = error("unable to move logfile logs/%s to logs/"TMP_RENAMED_LOG": %s", oldrefname, strerror(errno)); goto out; } - if (refs_delete_ref(&refs->base, logmsg, oldrefname, - orig_sha1, REF_NODEREF)) { + if (copy && log && copy_file(tmp_renamed_log.buf, sb_oldref.buf, 0644)) { + ret = error("unable to copy logfile logs/%s to logs/"TMP_RENAMED_LOG": %s", + oldrefname, strerror(errno)); + goto out; + } + + if (!copy && refs_delete_ref(&refs->base, logmsg, oldrefname, + &orig_oid, REF_NO_DEREF)) { error("unable to delete old %s", oldrefname); goto rollback; } /* - * Since we are doing a shallow lookup, sha1 is not the - * correct value to pass to delete_ref as old_sha1. But that - * doesn't matter, because an old_sha1 check wouldn't add to + * Since we are doing a shallow lookup, oid is not the + * correct value to pass to delete_ref as old_oid. But that + * doesn't matter, because an old_oid check wouldn't add to * the safety anyway; we want to delete the reference whatever * its current value. */ - if (!refs_read_ref_full(&refs->base, newrefname, + if (!copy && !refs_read_ref_full(&refs->base, newrefname, RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE, - sha1, NULL) && + &oid, NULL) && refs_delete_ref(&refs->base, NULL, newrefname, - NULL, REF_NODEREF)) { + NULL, REF_NO_DEREF)) { if (errno == EISDIR) { struct strbuf path = STRBUF_INIT; int result; @@ -1805,17 +1376,20 @@ static int files_rename_ref(struct ref_store *ref_store, logmoved = log; - lock = lock_ref_sha1_basic(refs, newrefname, NULL, NULL, NULL, - REF_NODEREF, NULL, &err); + lock = lock_ref_oid_basic(refs, newrefname, NULL, NULL, NULL, + REF_NO_DEREF, NULL, &err); if (!lock) { - error("unable to rename '%s' to '%s': %s", oldrefname, newrefname, err.buf); + if (copy) + error("unable to copy '%s' to '%s': %s", oldrefname, newrefname, err.buf); + else + error("unable to rename '%s' to '%s': %s", oldrefname, newrefname, err.buf); strbuf_release(&err); goto rollback; } - hashcpy(lock->old_oid.hash, orig_sha1); + oidcpy(&lock->old_oid, &orig_oid); - if (write_ref_to_lockfile(lock, orig_sha1, &err) || - commit_ref_update(refs, lock, orig_sha1, logmsg, &err)) { + if (write_ref_to_lockfile(lock, &orig_oid, &err) || + commit_ref_update(refs, lock, &orig_oid, logmsg, &err)) { error("unable to write current sha1 into %s: %s", newrefname, err.buf); strbuf_release(&err); goto rollback; @@ -1825,8 +1399,8 @@ static int files_rename_ref(struct ref_store *ref_store, goto out; rollback: - lock = lock_ref_sha1_basic(refs, oldrefname, NULL, NULL, NULL, - REF_NODEREF, NULL, &err); + lock = lock_ref_oid_basic(refs, oldrefname, NULL, NULL, NULL, + REF_NO_DEREF, NULL, &err); if (!lock) { error("unable to lock %s for rollback: %s", oldrefname, err.buf); strbuf_release(&err); @@ -1835,8 +1409,8 @@ static int files_rename_ref(struct ref_store *ref_store, flag = log_all_ref_updates; log_all_ref_updates = LOG_REFS_NONE; - if (write_ref_to_lockfile(lock, orig_sha1, &err) || - commit_ref_update(refs, lock, orig_sha1, NULL, &err)) { + if (write_ref_to_lockfile(lock, &orig_oid, &err) || + commit_ref_update(refs, lock, &orig_oid, NULL, &err)) { error("unable to write current sha1 into %s: %s", oldrefname, err.buf); strbuf_release(&err); } @@ -1859,16 +1433,32 @@ static int files_rename_ref(struct ref_store *ref_store, return ret; } -static int close_ref(struct ref_lock *lock) +static int files_rename_ref(struct ref_store *ref_store, + const char *oldrefname, const char *newrefname, + const char *logmsg) +{ + return files_copy_or_rename_ref(ref_store, oldrefname, + newrefname, logmsg, 0); +} + +static int files_copy_ref(struct ref_store *ref_store, + const char *oldrefname, const char *newrefname, + const char *logmsg) +{ + return files_copy_or_rename_ref(ref_store, oldrefname, + newrefname, logmsg, 1); +} + +static int close_ref_gently(struct ref_lock *lock) { - if (close_lock_file(lock->lk)) + if (close_lock_file_gently(&lock->lk)) return -1; return 0; } static int commit_ref(struct ref_lock *lock) { - char *path = get_locked_file_path(lock->lk); + char *path = get_locked_file_path(&lock->lk); struct stat st; if (!lstat(path, &st) && S_ISDIR(st.st_mode)) { @@ -1892,7 +1482,7 @@ static int commit_ref(struct ref_lock *lock) free(path); } - if (commit_lock_file(lock->lk)) + if (commit_lock_file(&lock->lk)) return -1; return 0; } @@ -1986,8 +1576,8 @@ static int files_create_reflog(struct ref_store *ref_store, return 0; } -static int log_ref_write_fd(int fd, const unsigned char *old_sha1, - const unsigned char *new_sha1, +static int log_ref_write_fd(int fd, const struct object_id *old_oid, + const struct object_id *new_oid, const char *committer, const char *msg) { int msglen, written; @@ -1998,23 +1588,23 @@ static int log_ref_write_fd(int fd, const unsigned char *old_sha1, maxlen = strlen(committer) + msglen + 100; logrec = xmalloc(maxlen); len = xsnprintf(logrec, maxlen, "%s %s %s\n", - sha1_to_hex(old_sha1), - sha1_to_hex(new_sha1), + oid_to_hex(old_oid), + oid_to_hex(new_oid), committer); if (msglen) len += copy_reflog_msg(logrec + len - 1, msg) - 1; written = len <= maxlen ? write_in_full(fd, logrec, len) : -1; free(logrec); - if (written != len) + if (written < 0) return -1; return 0; } static int files_log_ref_write(struct files_ref_store *refs, - const char *refname, const unsigned char *old_sha1, - const unsigned char *new_sha1, const char *msg, + const char *refname, const struct object_id *old_oid, + const struct object_id *new_oid, const char *msg, int flags, struct strbuf *err) { int logfd, result; @@ -2031,7 +1621,7 @@ static int files_log_ref_write(struct files_ref_store *refs, if (logfd < 0) return 0; - result = log_ref_write_fd(logfd, old_sha1, new_sha1, + result = log_ref_write_fd(logfd, old_oid, new_oid, git_committer_info(0), msg); if (result) { struct strbuf sb = STRBUF_INIT; @@ -2058,38 +1648,37 @@ static int files_log_ref_write(struct files_ref_store *refs, } /* - * Write sha1 into the open lockfile, then close the lockfile. On - * errors, rollback the lockfile, fill in *err and - * return -1. + * Write oid into the open lockfile, then close the lockfile. On + * errors, rollback the lockfile, fill in *err and return -1. */ static int write_ref_to_lockfile(struct ref_lock *lock, - const unsigned char *sha1, struct strbuf *err) + const struct object_id *oid, struct strbuf *err) { static char term = '\n'; struct object *o; int fd; - o = parse_object(sha1); + o = parse_object(oid); if (!o) { strbuf_addf(err, "trying to write ref '%s' with nonexistent object %s", - lock->ref_name, sha1_to_hex(sha1)); + lock->ref_name, oid_to_hex(oid)); unlock_ref(lock); return -1; } if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) { strbuf_addf(err, "trying to write non-commit object %s to branch '%s'", - sha1_to_hex(sha1), lock->ref_name); + oid_to_hex(oid), lock->ref_name); unlock_ref(lock); return -1; } - fd = get_lock_file_fd(lock->lk); - if (write_in_full(fd, sha1_to_hex(sha1), 40) != 40 || - write_in_full(fd, &term, 1) != 1 || - close_ref(lock) < 0) { + fd = get_lock_file_fd(&lock->lk); + if (write_in_full(fd, oid_to_hex(oid), GIT_SHA1_HEXSZ) < 0 || + write_in_full(fd, &term, 1) < 0 || + close_ref_gently(lock) < 0) { strbuf_addf(err, - "couldn't write '%s'", get_lock_file_path(lock->lk)); + "couldn't write '%s'", get_lock_file_path(&lock->lk)); unlock_ref(lock); return -1; } @@ -2103,14 +1692,14 @@ static int write_ref_to_lockfile(struct ref_lock *lock, */ static int commit_ref_update(struct files_ref_store *refs, struct ref_lock *lock, - const unsigned char *sha1, const char *logmsg, + const struct object_id *oid, const char *logmsg, struct strbuf *err) { files_assert_main_repository(refs, "commit_ref_update"); clear_loose_ref_cache(refs); if (files_log_ref_write(refs, lock->ref_name, - lock->old_oid.hash, sha1, + &lock->old_oid, oid, logmsg, 0, err)) { char *old_msg = strbuf_detach(err, NULL); strbuf_addf(err, "cannot update the ref '%s': %s", @@ -2133,18 +1722,17 @@ static int commit_ref_update(struct files_ref_store *refs, * check with HEAD only which should cover 99% of all usage * scenarios (even 100% of the default ones). */ - unsigned char head_sha1[20]; int head_flag; const char *head_ref; head_ref = refs_resolve_ref_unsafe(&refs->base, "HEAD", RESOLVE_REF_READING, - head_sha1, &head_flag); + NULL, &head_flag); if (head_ref && (head_flag & REF_ISSYMREF) && !strcmp(head_ref, lock->ref_name)) { struct strbuf log_err = STRBUF_INIT; if (files_log_ref_write(refs, "HEAD", - lock->old_oid.hash, sha1, + &lock->old_oid, oid, logmsg, 0, &log_err)) { error("%s", log_err.buf); strbuf_release(&log_err); @@ -2166,7 +1754,7 @@ static int create_ref_symlink(struct ref_lock *lock, const char *target) { int ret = -1; #ifndef NO_SYMLINK_HEAD - char *ref_path = get_locked_file_path(lock->lk); + char *ref_path = get_locked_file_path(&lock->lk); unlink(ref_path); ret = symlink(target, ref_path); free(ref_path); @@ -2182,12 +1770,12 @@ static void update_symref_reflog(struct files_ref_store *refs, const char *target, const char *logmsg) { struct strbuf err = STRBUF_INIT; - unsigned char new_sha1[20]; + struct object_id new_oid; if (logmsg && !refs_read_ref_full(&refs->base, target, - RESOLVE_REF_READING, new_sha1, NULL) && - files_log_ref_write(refs, refname, lock->old_oid.hash, - new_sha1, logmsg, 0, &err)) { + RESOLVE_REF_READING, &new_oid, NULL) && + files_log_ref_write(refs, refname, &lock->old_oid, + &new_oid, logmsg, 0, &err)) { error("%s", err.buf); strbuf_release(&err); } @@ -2202,14 +1790,14 @@ static int create_symref_locked(struct files_ref_store *refs, return 0; } - if (!fdopen_lock_file(lock->lk, "w")) + if (!fdopen_lock_file(&lock->lk, "w")) return error("unable to fdopen %s: %s", - lock->lk->tempfile.filename.buf, strerror(errno)); + lock->lk.tempfile->filename.buf, strerror(errno)); update_symref_reflog(refs, lock, refname, target, logmsg); /* no error check; commit_ref will check ferror */ - fprintf(lock->lk->tempfile.fp, "ref: %s\n", target); + fprintf(lock->lk.tempfile->fp, "ref: %s\n", target); if (commit_ref(lock) < 0) return error("unable to write symref for %s: %s", refname, strerror(errno)); @@ -2226,9 +1814,9 @@ static int files_create_symref(struct ref_store *ref_store, struct ref_lock *lock; int ret; - lock = lock_ref_sha1_basic(refs, refname, NULL, - NULL, NULL, REF_NODEREF, NULL, - &err); + lock = lock_ref_oid_basic(refs, refname, NULL, + NULL, NULL, REF_NO_DEREF, NULL, + &err); if (!lock) { error("%s", err.buf); strbuf_release(&err); @@ -2240,50 +1828,6 @@ static int files_create_symref(struct ref_store *ref_store, return ret; } -int set_worktree_head_symref(const char *gitdir, const char *target, const char *logmsg) -{ - /* - * FIXME: this obviously will not work well for future refs - * backends. This function needs to die. - */ - struct files_ref_store *refs = - files_downcast(get_main_ref_store(), - REF_STORE_WRITE, - "set_head_symref"); - - static struct lock_file head_lock; - struct ref_lock *lock; - struct strbuf head_path = STRBUF_INIT; - const char *head_rel; - int ret; - - strbuf_addf(&head_path, "%s/HEAD", absolute_path(gitdir)); - if (hold_lock_file_for_update(&head_lock, head_path.buf, - LOCK_NO_DEREF) < 0) { - struct strbuf err = STRBUF_INIT; - unable_to_lock_message(head_path.buf, errno, &err); - error("%s", err.buf); - strbuf_release(&err); - strbuf_release(&head_path); - return -1; - } - - /* head_rel will be "HEAD" for the main tree, "worktrees/wt/HEAD" for - linked trees */ - head_rel = remove_leading_path(head_path.buf, - absolute_path(get_git_common_dir())); - /* to make use of create_symref_locked(), initialize ref_lock */ - lock = xcalloc(1, sizeof(struct ref_lock)); - lock->lk = &head_lock; - lock->ref_name = xstrdup(head_rel); - - ret = create_symref_locked(refs, lock, head_rel, target, logmsg); - - unlock_ref(lock); /* will free lock */ - strbuf_release(&head_path); - return ret; -} - static int files_reflog_exists(struct ref_store *ref_store, const char *refname) { @@ -2317,7 +1861,7 @@ static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *c { struct object_id ooid, noid; char *email_end, *message; - unsigned long timestamp; + timestamp_t timestamp; int tz; const char *p = sb->buf; @@ -2327,7 +1871,7 @@ static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *c parse_oid_hex(p, &noid, &p) || *p++ != ' ' || !(email_end = strchr(p, '>')) || email_end[1] != ' ' || - !(timestamp = strtoul(email_end + 2, &message, 10)) || + !(timestamp = parse_timestamp(email_end + 2, &message, 10)) || !message || message[0] != ' ' || (message[1] != '+' && message[1] != '-') || !isdigit(message[2]) || !isdigit(message[3]) || @@ -2518,7 +2062,7 @@ static int files_reflog_iterator_advance(struct ref_iterator *ref_iterator) if (refs_read_ref_full(iter->ref_store, diter->relative_path, 0, - iter->oid.hash, &flags)) { + &iter->oid, &flags)) { error("bad ref for %s", diter->path.buf); continue; } @@ -2560,38 +2104,62 @@ static struct ref_iterator_vtable files_reflog_iterator_vtable = { files_reflog_iterator_abort }; -static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_store) +static struct ref_iterator *reflog_iterator_begin(struct ref_store *ref_store, + const char *gitdir) { - struct files_ref_store *refs = - files_downcast(ref_store, REF_STORE_READ, - "reflog_iterator_begin"); struct files_reflog_iterator *iter = xcalloc(1, sizeof(*iter)); struct ref_iterator *ref_iterator = &iter->base; struct strbuf sb = STRBUF_INIT; - base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable); - files_reflog_path(refs, &sb, NULL); + base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable, 0); + strbuf_addf(&sb, "%s/logs", gitdir); iter->dir_iterator = dir_iterator_begin(sb.buf); iter->ref_store = ref_store; strbuf_release(&sb); + return ref_iterator; } -static int ref_update_reject_duplicates(struct string_list *refnames, - struct strbuf *err) +static enum iterator_selection reflog_iterator_select( + struct ref_iterator *iter_worktree, + struct ref_iterator *iter_common, + void *cb_data) { - int i, n = refnames->nr; + if (iter_worktree) { + /* + * We're a bit loose here. We probably should ignore + * common refs if they are accidentally added as + * per-worktree refs. + */ + return ITER_SELECT_0; + } else if (iter_common) { + if (ref_type(iter_common->refname) == REF_TYPE_NORMAL) + return ITER_SELECT_1; - assert(err); + /* + * The main ref store may contain main worktree's + * per-worktree refs, which should be ignored + */ + return ITER_SKIP_1; + } else + return ITER_DONE; +} - for (i = 1; i < n; i++) - if (!strcmp(refnames->items[i - 1].string, refnames->items[i].string)) { - strbuf_addf(err, - "multiple updates for ref '%s' not allowed.", - refnames->items[i].string); - return 1; - } - return 0; +static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_store) +{ + struct files_ref_store *refs = + files_downcast(ref_store, REF_STORE_READ, + "reflog_iterator_begin"); + + if (!strcmp(refs->gitdir, refs->gitcommondir)) { + return reflog_iterator_begin(ref_store, refs->gitcommondir); + } else { + return merge_ref_iterator_begin( + 0, + reflog_iterator_begin(ref_store, refs->gitdir), + reflog_iterator_begin(ref_store, refs->gitcommondir), + reflog_iterator_select, refs); + } } /* @@ -2608,7 +2176,7 @@ static int split_head_update(struct ref_update *update, struct ref_update *new_update; if ((update->flags & REF_LOG_ONLY) || - (update->flags & REF_ISPRUNING) || + (update->flags & REF_IS_PRUNING) || (update->flags & REF_UPDATE_VIA_HEAD)) return 0; @@ -2617,11 +2185,10 @@ static int split_head_update(struct ref_update *update, /* * First make sure that HEAD is not already in the - * transaction. This insertion is O(N) in the transaction + * transaction. This check is O(lg N) in the transaction * size, but it happens at most once per transaction. */ - item = string_list_insert(affected_refnames, "HEAD"); - if (item->util) { + if (string_list_has_string(affected_refnames, "HEAD")) { /* An entry already existed */ strbuf_addf(err, "multiple updates for 'HEAD' (including one " @@ -2632,10 +2199,18 @@ static int split_head_update(struct ref_update *update, new_update = ref_transaction_add_update( transaction, "HEAD", - update->flags | REF_LOG_ONLY | REF_NODEREF, - update->new_sha1, update->old_sha1, + update->flags | REF_LOG_ONLY | REF_NO_DEREF, + &update->new_oid, &update->old_oid, update->msg); + /* + * Add "HEAD". This insertion is O(N) in the transaction + * size, but it happens at most once per transaction. + * Add new_update->refname instead of a literal "HEAD". + */ + if (strcmp(new_update->refname, "HEAD")) + BUG("%s unexpectedly not 'HEAD'", new_update->refname); + item = string_list_insert(affected_refnames, new_update->refname); item->util = new_update; return 0; @@ -2643,8 +2218,8 @@ static int split_head_update(struct ref_update *update, /* * update is for a symref that points at referent and doesn't have - * REF_NODEREF set. Split it into two updates: - * - The original update, but with REF_LOG_ONLY and REF_NODEREF set + * REF_NO_DEREF set. Split it into two updates: + * - The original update, but with REF_LOG_ONLY and REF_NO_DEREF set * - A new, separate update for the referent reference * Note that the new update will itself be subject to splitting when * the iteration gets to it. @@ -2662,13 +2237,12 @@ static int split_symref_update(struct files_ref_store *refs, /* * First make sure that referent is not already in the - * transaction. This insertion is O(N) in the transaction + * transaction. This check is O(lg N) in the transaction * size, but it happens at most once per symref in a * transaction. */ - item = string_list_insert(affected_refnames, referent); - if (item->util) { - /* An entry already existed */ + if (string_list_has_string(affected_refnames, referent)) { + /* An entry already exists */ strbuf_addf(err, "multiple updates for '%s' (including one " "via symref '%s') are not allowed", @@ -2690,19 +2264,30 @@ static int split_symref_update(struct files_ref_store *refs, new_update = ref_transaction_add_update( transaction, referent, new_flags, - update->new_sha1, update->old_sha1, + &update->new_oid, &update->old_oid, update->msg); new_update->parent_update = update; /* * Change the symbolic ref update to log only. Also, it - * doesn't need to check its old SHA-1 value, as that will be + * doesn't need to check its old OID value, as that will be * done when new_update is processed. */ - update->flags |= REF_LOG_ONLY | REF_NODEREF; + update->flags |= REF_LOG_ONLY | REF_NO_DEREF; update->flags &= ~REF_HAVE_OLD; + /* + * Add the referent. This insertion is O(N) in the transaction + * size, but it happens at most once per symref in a + * transaction. Make sure to add new_update->refname, which will + * be valid as long as affected_refnames is in use, and NOT + * referent, which might soon be freed by our caller. + */ + item = string_list_insert(affected_refnames, new_update->refname); + if (item->util) + BUG("%s unexpectedly found in affected_refnames", + new_update->refname); item->util = new_update; return 0; @@ -2729,10 +2314,10 @@ static int check_old_oid(struct ref_update *update, struct object_id *oid, struct strbuf *err) { if (!(update->flags & REF_HAVE_OLD) || - !hashcmp(oid->hash, update->old_sha1)) + !oidcmp(oid, &update->old_oid)) return 0; - if (is_null_sha1(update->old_sha1)) + if (is_null_oid(&update->old_oid)) strbuf_addf(err, "cannot lock ref '%s': " "reference already exists", original_update_refname(update)); @@ -2740,13 +2325,13 @@ static int check_old_oid(struct ref_update *update, struct object_id *oid, strbuf_addf(err, "cannot lock ref '%s': " "reference is missing but expected %s", original_update_refname(update), - sha1_to_hex(update->old_sha1)); + oid_to_hex(&update->old_oid)); else strbuf_addf(err, "cannot lock ref '%s': " "is at %s but expected %s", original_update_refname(update), oid_to_hex(oid), - sha1_to_hex(update->old_sha1)); + oid_to_hex(&update->old_oid)); return -1; } @@ -2755,10 +2340,10 @@ static int check_old_oid(struct ref_update *update, struct object_id *oid, * Prepare for carrying out update: * - Lock the reference referred to by update. * - Read the reference under lock. - * - Check that its old SHA-1 value (if specified) is correct, and in + * - Check that its old OID value (if specified) is correct, and in * any case record it in update->lock->old_oid for later use when * writing the reflog. - * - If it is a symref update without REF_NODEREF, split it up into a + * - If it is a symref update without REF_NO_DEREF, split it up into a * REF_LOG_ONLY update of the symref and add a separate update for * the referent to transaction. * - If it is an update of head_ref, add a corresponding REF_LOG_ONLY @@ -2773,20 +2358,20 @@ static int lock_ref_for_update(struct files_ref_store *refs, { struct strbuf referent = STRBUF_INIT; int mustexist = (update->flags & REF_HAVE_OLD) && - !is_null_sha1(update->old_sha1); - int ret; + !is_null_oid(&update->old_oid); + int ret = 0; struct ref_lock *lock; files_assert_main_repository(refs, "lock_ref_for_update"); - if ((update->flags & REF_HAVE_NEW) && is_null_sha1(update->new_sha1)) + if ((update->flags & REF_HAVE_NEW) && is_null_oid(&update->new_oid)) update->flags |= REF_DELETING; if (head_ref) { ret = split_head_update(update, transaction, head_ref, affected_refnames, err); if (ret) - return ret; + goto out; } ret = lock_raw_ref(refs, update->refname, mustexist, @@ -2800,35 +2385,37 @@ static int lock_ref_for_update(struct files_ref_store *refs, strbuf_addf(err, "cannot lock ref '%s': %s", original_update_refname(update), reason); free(reason); - return ret; + goto out; } update->backend_data = lock; if (update->type & REF_ISSYMREF) { - if (update->flags & REF_NODEREF) { + if (update->flags & REF_NO_DEREF) { /* * We won't be reading the referent as part of * the transaction, so we have to read it here - * to record and possibly check old_sha1: + * to record and possibly check old_oid: */ if (refs_read_ref_full(&refs->base, referent.buf, 0, - lock->old_oid.hash, NULL)) { + &lock->old_oid, NULL)) { if (update->flags & REF_HAVE_OLD) { strbuf_addf(err, "cannot lock ref '%s': " "error reading reference", original_update_refname(update)); - return -1; + ret = TRANSACTION_GENERIC_ERROR; + goto out; } } else if (check_old_oid(update, &lock->old_oid, err)) { - return TRANSACTION_GENERIC_ERROR; + ret = TRANSACTION_GENERIC_ERROR; + goto out; } } else { /* * Create a new update for the reference this * symref is pointing at. Also, we will record - * and verify old_sha1 for this update as part + * and verify old_oid for this update as part * of processing the split-off update, so we * don't have to do it here. */ @@ -2836,17 +2423,19 @@ static int lock_ref_for_update(struct files_ref_store *refs, referent.buf, transaction, affected_refnames, err); if (ret) - return ret; + goto out; } } else { struct ref_update *parent_update; - if (check_old_oid(update, &lock->old_oid, err)) - return TRANSACTION_GENERIC_ERROR; + if (check_old_oid(update, &lock->old_oid, err)) { + ret = TRANSACTION_GENERIC_ERROR; + goto out; + } /* * If this update is happening indirectly because of a - * symref update, record the old SHA-1 in the parent + * symref update, record the old OID in the parent * update: */ for (parent_update = update->parent_update; @@ -2861,12 +2450,12 @@ static int lock_ref_for_update(struct files_ref_store *refs, !(update->flags & REF_DELETING) && !(update->flags & REF_LOG_ONLY)) { if (!(update->type & REF_ISSYMREF) && - !hashcmp(lock->old_oid.hash, update->new_sha1)) { + !oidcmp(&lock->old_oid, &update->new_oid)) { /* * The reference already has the desired * value, so we don't need to write it. */ - } else if (write_ref_to_lockfile(lock, update->new_sha1, + } else if (write_ref_to_lockfile(lock, &update->new_oid, err)) { char *write_err = strbuf_detach(err, NULL); @@ -2879,7 +2468,8 @@ static int lock_ref_for_update(struct files_ref_store *refs, "cannot update ref '%s': %s", update->refname, write_err); free(write_err); - return TRANSACTION_GENERIC_ERROR; + ret = TRANSACTION_GENERIC_ERROR; + goto out; } else { update->flags |= REF_NEEDS_COMMIT; } @@ -2890,53 +2480,100 @@ static int lock_ref_for_update(struct files_ref_store *refs, * the lockfile is still open. Close it to * free up the file descriptor: */ - if (close_ref(lock)) { + if (close_ref_gently(lock)) { strbuf_addf(err, "couldn't close '%s.lock'", update->refname); - return TRANSACTION_GENERIC_ERROR; + ret = TRANSACTION_GENERIC_ERROR; + goto out; } } - return 0; + +out: + strbuf_release(&referent); + return ret; } -static int files_transaction_commit(struct ref_store *ref_store, - struct ref_transaction *transaction, - struct strbuf *err) +struct files_transaction_backend_data { + struct ref_transaction *packed_transaction; + int packed_refs_locked; +}; + +/* + * Unlock any references in `transaction` that are still locked, and + * mark the transaction closed. + */ +static void files_transaction_cleanup(struct files_ref_store *refs, + struct ref_transaction *transaction) +{ + size_t i; + struct files_transaction_backend_data *backend_data = + transaction->backend_data; + struct strbuf err = STRBUF_INIT; + + for (i = 0; i < transaction->nr; i++) { + struct ref_update *update = transaction->updates[i]; + struct ref_lock *lock = update->backend_data; + + if (lock) { + unlock_ref(lock); + update->backend_data = NULL; + } + } + + if (backend_data->packed_transaction && + ref_transaction_abort(backend_data->packed_transaction, &err)) { + error("error aborting transaction: %s", err.buf); + strbuf_release(&err); + } + + if (backend_data->packed_refs_locked) + packed_refs_unlock(refs->packed_ref_store); + + free(backend_data); + + transaction->state = REF_TRANSACTION_CLOSED; +} + +static int files_transaction_prepare(struct ref_store *ref_store, + struct ref_transaction *transaction, + struct strbuf *err) { struct files_ref_store *refs = files_downcast(ref_store, REF_STORE_WRITE, - "ref_transaction_commit"); - int ret = 0, i; - struct string_list refs_to_delete = STRING_LIST_INIT_NODUP; - struct string_list_item *ref_to_delete; + "ref_transaction_prepare"); + size_t i; + int ret = 0; struct string_list affected_refnames = STRING_LIST_INIT_NODUP; char *head_ref = NULL; int head_type; - struct object_id head_oid; - struct strbuf sb = STRBUF_INIT; + struct files_transaction_backend_data *backend_data; + struct ref_transaction *packed_transaction = NULL; assert(err); - if (transaction->state != REF_TRANSACTION_OPEN) - die("BUG: commit called for transaction that is not open"); + if (!transaction->nr) + goto cleanup; - if (!transaction->nr) { - transaction->state = REF_TRANSACTION_CLOSED; - return 0; - } + backend_data = xcalloc(1, sizeof(*backend_data)); + transaction->backend_data = backend_data; /* * Fail if a refname appears more than once in the * transaction. (If we end up splitting up any updates using * split_symref_update() or split_head_update(), those * functions will check that the new updates don't have the - * same refname as any existing ones.) + * same refname as any existing ones.) Also fail if any of the + * updates use REF_IS_PRUNING without REF_NO_DEREF. */ for (i = 0; i < transaction->nr; i++) { struct ref_update *update = transaction->updates[i]; struct string_list_item *item = string_list_append(&affected_refnames, update->refname); + if ((update->flags & REF_IS_PRUNING) && + !(update->flags & REF_NO_DEREF)) + BUG("REF_IS_PRUNING set without REF_NO_DEREF"); + /* * We store a pointer to update in item->util, but at * the moment we never use the value of this field @@ -2970,11 +2607,10 @@ static int files_transaction_commit(struct ref_store *ref_store, */ head_ref = refs_resolve_refdup(ref_store, "HEAD", RESOLVE_REF_NO_RECURSE, - head_oid.hash, &head_type); + NULL, &head_type); if (head_ref && !(head_type & REF_ISSYMREF)) { - free(head_ref); - head_ref = NULL; + FREE_AND_NULL(head_ref); } /* @@ -2982,6 +2618,8 @@ static int files_transaction_commit(struct ref_store *ref_store, * that new values are valid, and write new values to the * lockfiles, ready to be activated. Only keep one lockfile * open at a time to avoid running out of file descriptors. + * Note that lock_ref_for_update() might append more updates + * to the transaction. */ for (i = 0; i < transaction->nr; i++) { struct ref_update *update = transaction->updates[i]; @@ -2990,8 +2628,94 @@ static int files_transaction_commit(struct ref_store *ref_store, head_ref, &affected_refnames, err); if (ret) goto cleanup; + + if (update->flags & REF_DELETING && + !(update->flags & REF_LOG_ONLY) && + !(update->flags & REF_IS_PRUNING)) { + /* + * This reference has to be deleted from + * packed-refs if it exists there. + */ + if (!packed_transaction) { + packed_transaction = ref_store_transaction_begin( + refs->packed_ref_store, err); + if (!packed_transaction) { + ret = TRANSACTION_GENERIC_ERROR; + goto cleanup; + } + + backend_data->packed_transaction = + packed_transaction; + } + + ref_transaction_add_update( + packed_transaction, update->refname, + REF_HAVE_NEW | REF_NO_DEREF, + &update->new_oid, NULL, + NULL); + } + } + + if (packed_transaction) { + if (packed_refs_lock(refs->packed_ref_store, 0, err)) { + ret = TRANSACTION_GENERIC_ERROR; + goto cleanup; + } + backend_data->packed_refs_locked = 1; + + if (is_packed_transaction_needed(refs->packed_ref_store, + packed_transaction)) { + ret = ref_transaction_prepare(packed_transaction, err); + } else { + /* + * We can skip rewriting the `packed-refs` + * file. But we do need to leave it locked, so + * that somebody else doesn't pack a reference + * that we are trying to delete. + */ + if (ref_transaction_abort(packed_transaction, err)) { + ret = TRANSACTION_GENERIC_ERROR; + goto cleanup; + } + backend_data->packed_transaction = NULL; + } } +cleanup: + free(head_ref); + string_list_clear(&affected_refnames, 0); + + if (ret) + files_transaction_cleanup(refs, transaction); + else + transaction->state = REF_TRANSACTION_PREPARED; + + return ret; +} + +static int files_transaction_finish(struct ref_store *ref_store, + struct ref_transaction *transaction, + struct strbuf *err) +{ + struct files_ref_store *refs = + files_downcast(ref_store, 0, "ref_transaction_finish"); + size_t i; + int ret = 0; + struct strbuf sb = STRBUF_INIT; + struct files_transaction_backend_data *backend_data; + struct ref_transaction *packed_transaction; + + + assert(err); + + if (!transaction->nr) { + transaction->state = REF_TRANSACTION_CLOSED; + return 0; + } + + backend_data = transaction->backend_data; + packed_transaction = backend_data->packed_transaction; + /* Perform updates first so live commits remain referenced */ for (i = 0; i < transaction->nr; i++) { struct ref_update *update = transaction->updates[i]; @@ -3001,8 +2725,8 @@ static int files_transaction_commit(struct ref_store *ref_store, update->flags & REF_LOG_ONLY) { if (files_log_ref_write(refs, lock->ref_name, - lock->old_oid.hash, - update->new_sha1, + &lock->old_oid, + &update->new_oid, update->msg, update->flags, err)) { char *old_msg = strbuf_detach(err, NULL); @@ -3027,7 +2751,44 @@ static int files_transaction_commit(struct ref_store *ref_store, } } } - /* Perform deletes now that updates are safely completed */ + + /* + * Now that updates are safely completed, we can perform + * deletes. First delete the reflogs of any references that + * will be deleted, since (in the unexpected event of an + * error) leaving a reference without a reflog is less bad + * than leaving a reflog without a reference (the latter is a + * mildly invalid repository state): + */ + for (i = 0; i < transaction->nr; i++) { + struct ref_update *update = transaction->updates[i]; + if (update->flags & REF_DELETING && + !(update->flags & REF_LOG_ONLY) && + !(update->flags & REF_IS_PRUNING)) { + strbuf_reset(&sb); + files_reflog_path(refs, &sb, update->refname); + if (!unlink_or_warn(sb.buf)) + try_remove_empty_parents(refs, update->refname, + REMOVE_EMPTY_PARENTS_REFLOG); + } + } + + /* + * Perform deletes now that updates are safely completed. + * + * First delete any packed versions of the references, while + * retaining the packed-refs lock: + */ + if (packed_transaction) { + ret = ref_transaction_commit(packed_transaction, err); + ref_transaction_free(packed_transaction); + packed_transaction = NULL; + backend_data->packed_transaction = NULL; + if (ret) + goto cleanup; + } + + /* Now delete the loose versions of the references: */ for (i = 0; i < transaction->nr; i++) { struct ref_update *update = transaction->updates[i]; struct ref_lock *lock = update->backend_data; @@ -3045,39 +2806,16 @@ static int files_transaction_commit(struct ref_store *ref_store, } update->flags |= REF_DELETED_LOOSE; } - - if (!(update->flags & REF_ISPRUNING)) - string_list_append(&refs_to_delete, - lock->ref_name); } } - if (repack_without_refs(refs, &refs_to_delete, err)) { - ret = TRANSACTION_GENERIC_ERROR; - goto cleanup; - } - - /* Delete the reflogs of any references that were deleted: */ - for_each_string_list_item(ref_to_delete, &refs_to_delete) { - strbuf_reset(&sb); - files_reflog_path(refs, &sb, ref_to_delete->string); - if (!unlink_or_warn(sb.buf)) - try_remove_empty_parents(refs, ref_to_delete->string, - REMOVE_EMPTY_PARENTS_REFLOG); - } - clear_loose_ref_cache(refs); cleanup: - strbuf_release(&sb); - transaction->state = REF_TRANSACTION_CLOSED; + files_transaction_cleanup(refs, transaction); for (i = 0; i < transaction->nr; i++) { struct ref_update *update = transaction->updates[i]; - struct ref_lock *lock = update->backend_data; - - if (lock) - unlock_ref(lock); if (update->flags & REF_DELETED_LOOSE) { /* @@ -3091,13 +2829,21 @@ cleanup: } } - string_list_clear(&refs_to_delete, 0); - free(head_ref); - string_list_clear(&affected_refnames, 0); - + strbuf_release(&sb); return ret; } +static int files_transaction_abort(struct ref_store *ref_store, + struct ref_transaction *transaction, + struct strbuf *err) +{ + struct files_ref_store *refs = + files_downcast(ref_store, 0, "ref_transaction_abort"); + + files_transaction_cleanup(refs, transaction); + return 0; +} + static int ref_present(const char *refname, const struct object_id *oid, int flags, void *cb_data) { @@ -3113,8 +2859,10 @@ static int files_initial_transaction_commit(struct ref_store *ref_store, struct files_ref_store *refs = files_downcast(ref_store, REF_STORE_WRITE, "initial_ref_transaction_commit"); - int ret = 0, i; + size_t i; + int ret = 0; struct string_list affected_refnames = STRING_LIST_INIT_NODUP; + struct ref_transaction *packed_transaction = NULL; assert(err); @@ -3147,11 +2895,17 @@ static int files_initial_transaction_commit(struct ref_store *ref_store, &affected_refnames)) die("BUG: initial ref transaction called with existing refs"); + packed_transaction = ref_store_transaction_begin(refs->packed_ref_store, err); + if (!packed_transaction) { + ret = TRANSACTION_GENERIC_ERROR; + goto cleanup; + } + for (i = 0; i < transaction->nr; i++) { struct ref_update *update = transaction->updates[i]; if ((update->flags & REF_HAVE_OLD) && - !is_null_sha1(update->old_sha1)) + !is_null_oid(&update->old_oid)) die("BUG: initial ref transaction with old_sha1 set"); if (refs_verify_refname_available(&refs->base, update->refname, &affected_refnames, NULL, @@ -3159,31 +2913,30 @@ static int files_initial_transaction_commit(struct ref_store *ref_store, ret = TRANSACTION_NAME_CONFLICT; goto cleanup; } + + /* + * Add a reference creation for this reference to the + * packed-refs transaction: + */ + ref_transaction_add_update(packed_transaction, update->refname, + update->flags & ~REF_HAVE_OLD, + &update->new_oid, &update->old_oid, + NULL); } - 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; } - for (i = 0; i < transaction->nr; i++) { - struct ref_update *update = transaction->updates[i]; - - if ((update->flags & REF_HAVE_NEW) && - !is_null_sha1(update->new_sha1)) - add_packed_ref(refs, update->refname, update->new_sha1); - } - - if (commit_packed_refs(refs)) { - strbuf_addf(err, "unable to commit packed-refs file: %s", - strerror(errno)); + if (initial_ref_transaction_commit(packed_transaction, err)) { ret = TRANSACTION_GENERIC_ERROR; - goto cleanup; } + packed_refs_unlock(refs->packed_ref_store); cleanup: + if (packed_transaction) + ref_transaction_free(packed_transaction); transaction->state = REF_TRANSACTION_CLOSED; string_list_clear(&affected_refnames, 0); return ret; @@ -3198,7 +2951,7 @@ struct expire_reflog_cb { }; static int expire_reflog_ent(struct object_id *ooid, struct object_id *noid, - const char *email, unsigned long timestamp, int tz, + const char *email, timestamp_t timestamp, int tz, const char *message, void *cb_data) { struct expire_reflog_cb *cb = cb_data; @@ -3207,7 +2960,7 @@ static int expire_reflog_ent(struct object_id *ooid, struct object_id *noid, if (cb->flags & EXPIRE_REFLOGS_REWRITE) ooid = &cb->last_kept_oid; - if ((*cb->should_prune_fn)(ooid->hash, noid->hash, email, timestamp, tz, + if ((*cb->should_prune_fn)(ooid, noid, email, timestamp, tz, message, policy_cb)) { if (!cb->newlog) printf("would prune %s", message); @@ -3215,7 +2968,7 @@ static int expire_reflog_ent(struct object_id *ooid, struct object_id *noid, printf("prune %s", message); } else { if (cb->newlog) { - fprintf(cb->newlog, "%s %s %s %lu %+05d\t%s", + fprintf(cb->newlog, "%s %s %s %"PRItime" %+05d\t%s", oid_to_hex(ooid), oid_to_hex(noid), email, timestamp, tz, message); oidcpy(&cb->last_kept_oid, noid); @@ -3227,7 +2980,7 @@ static int expire_reflog_ent(struct object_id *ooid, struct object_id *noid, } static int files_reflog_expire(struct ref_store *ref_store, - const char *refname, const unsigned char *sha1, + const char *refname, const struct object_id *oid, unsigned int flags, reflog_expiry_prepare_fn prepare_fn, reflog_expiry_should_prune_fn should_prune_fn, @@ -3255,9 +3008,9 @@ static int files_reflog_expire(struct ref_store *ref_store, * reference itself, plus we might need to update the * reference if --updateref was specified: */ - lock = lock_ref_sha1_basic(refs, refname, sha1, - NULL, NULL, REF_NODEREF, - &type, &err); + lock = lock_ref_oid_basic(refs, refname, oid, + NULL, NULL, REF_NO_DEREF, + &type, &err); if (!lock) { error("cannot lock ref '%s': %s", refname, err.buf); strbuf_release(&err); @@ -3293,7 +3046,7 @@ static int files_reflog_expire(struct ref_store *ref_store, } } - (*prepare_fn)(refname, sha1, cb.policy_cb); + (*prepare_fn)(refname, oid, cb.policy_cb); refs_for_each_reflog_ent(ref_store, refname, expire_reflog_ent, &cb); (*cleanup_fn)(cb.policy_cb); @@ -3309,16 +3062,17 @@ static int files_reflog_expire(struct ref_store *ref_store, !(type & REF_ISSYMREF) && !is_null_oid(&cb.last_kept_oid); - if (close_lock_file(&reflog_lock)) { + if (close_lock_file_gently(&reflog_lock)) { status |= error("couldn't write %s: %s", log_file, strerror(errno)); + rollback_lock_file(&reflog_lock); } else if (update && - (write_in_full(get_lock_file_fd(lock->lk), - oid_to_hex(&cb.last_kept_oid), GIT_SHA1_HEXSZ) != GIT_SHA1_HEXSZ || - write_str_in_full(get_lock_file_fd(lock->lk), "\n") != 1 || - close_ref(lock) < 0)) { + (write_in_full(get_lock_file_fd(&lock->lk), + oid_to_hex(&cb.last_kept_oid), GIT_SHA1_HEXSZ) < 0 || + write_str_in_full(get_lock_file_fd(&lock->lk), "\n") < 0 || + close_ref_gently(lock) < 0)) { status |= error("couldn't write %s", - get_lock_file_path(lock->lk)); + get_lock_file_path(&lock->lk)); rollback_lock_file(&reflog_lock); } else if (commit_lock_file(&reflog_lock)) { status |= error("unable to write reflog '%s' (%s)", @@ -3363,14 +3117,16 @@ struct ref_storage_be refs_be_files = { "files", files_ref_store_create, files_init_db, - files_transaction_commit, + files_transaction_prepare, + files_transaction_finish, + files_transaction_abort, files_initial_transaction_commit, files_pack_refs, - files_peel_ref, files_create_symref, files_delete_refs, files_rename_ref, + files_copy_ref, files_ref_iterator_begin, files_read_raw_ref, diff --git a/refs/iterator.c b/refs/iterator.c index bce1f192f7..bd35da4e62 100644 --- a/refs/iterator.c +++ b/refs/iterator.c @@ -25,9 +25,11 @@ int ref_iterator_abort(struct ref_iterator *ref_iterator) } void base_ref_iterator_init(struct ref_iterator *iter, - struct ref_iterator_vtable *vtable) + struct ref_iterator_vtable *vtable, + int ordered) { iter->vtable = vtable; + iter->ordered = !!ordered; iter->refname = NULL; iter->oid = NULL; iter->flags = 0; @@ -72,7 +74,7 @@ struct ref_iterator *empty_ref_iterator_begin(void) struct empty_ref_iterator *iter = xcalloc(1, sizeof(*iter)); struct ref_iterator *ref_iterator = &iter->base; - base_ref_iterator_init(ref_iterator, &empty_ref_iterator_vtable); + base_ref_iterator_init(ref_iterator, &empty_ref_iterator_vtable, 1); return ref_iterator; } @@ -205,6 +207,7 @@ static struct ref_iterator_vtable merge_ref_iterator_vtable = { }; struct ref_iterator *merge_ref_iterator_begin( + int ordered, struct ref_iterator *iter0, struct ref_iterator *iter1, ref_iterator_select_fn *select, void *cb_data) { @@ -219,7 +222,7 @@ struct ref_iterator *merge_ref_iterator_begin( * references through only if they exist in both iterators. */ - base_ref_iterator_init(ref_iterator, &merge_ref_iterator_vtable); + base_ref_iterator_init(ref_iterator, &merge_ref_iterator_vtable, ordered); iter->iter0 = iter0; iter->iter1 = iter1; iter->select = select; @@ -268,9 +271,11 @@ struct ref_iterator *overlay_ref_iterator_begin( } else if (is_empty_ref_iterator(back)) { ref_iterator_abort(back); return front; + } else if (!front->ordered || !back->ordered) { + BUG("overlay_ref_iterator requires ordered inputs"); } - return merge_ref_iterator_begin(front, back, + return merge_ref_iterator_begin(1, front, back, overlay_iterator_select, NULL); } @@ -282,6 +287,20 @@ struct prefix_ref_iterator { int trim; }; +/* Return -1, 0, 1 if refname is before, inside, or after the prefix. */ +static int compare_prefix(const char *refname, const char *prefix) +{ + while (*prefix) { + if (*refname != *prefix) + return ((unsigned char)*refname < (unsigned char)*prefix) ? -1 : +1; + + refname++; + prefix++; + } + + return 0; +} + static int prefix_ref_iterator_advance(struct ref_iterator *ref_iterator) { struct prefix_ref_iterator *iter = @@ -289,10 +308,42 @@ static int prefix_ref_iterator_advance(struct ref_iterator *ref_iterator) int ok; while ((ok = ref_iterator_advance(iter->iter0)) == ITER_OK) { - if (!starts_with(iter->iter0->refname, iter->prefix)) + int cmp = compare_prefix(iter->iter0->refname, iter->prefix); + + if (cmp < 0) continue; - iter->base.refname = iter->iter0->refname + iter->trim; + if (cmp > 0) { + /* + * If the source iterator is ordered, then we + * can stop the iteration as soon as we see a + * refname that comes after the prefix: + */ + if (iter->iter0->ordered) { + ok = ref_iterator_abort(iter->iter0); + break; + } else { + continue; + } + } + + if (iter->trim) { + /* + * It is nonsense to trim off characters that + * you haven't already checked for via a + * prefix check, whether via this + * `prefix_ref_iterator` or upstream in + * `iter0`). So if there wouldn't be at least + * one character left in the refname after + * trimming, report it as a bug: + */ + if (strlen(iter->iter0->refname) <= iter->trim) + die("BUG: attempt to trim too many characters"); + iter->base.refname = iter->iter0->refname + iter->trim; + } else { + iter->base.refname = iter->iter0->refname; + } + iter->base.oid = iter->iter0->oid; iter->base.flags = iter->iter0->flags; return ITER_OK; @@ -345,7 +396,7 @@ struct ref_iterator *prefix_ref_iterator_begin(struct ref_iterator *iter0, iter = xcalloc(1, sizeof(*iter)); ref_iterator = &iter->base; - base_ref_iterator_init(ref_iterator, &prefix_ref_iterator_vtable); + base_ref_iterator_init(ref_iterator, &prefix_ref_iterator_vtable, iter0->ordered); iter->iter0 = iter0; iter->prefix = xstrdup(prefix); diff --git a/refs/packed-backend.c b/refs/packed-backend.c new file mode 100644 index 0000000000..65288c6472 --- /dev/null +++ b/refs/packed-backend.c @@ -0,0 +1,1656 @@ +#include "../cache.h" +#include "../config.h" +#include "../refs.h" +#include "refs-internal.h" +#include "packed-backend.h" +#include "../iterator.h" +#include "../lockfile.h" + +enum mmap_strategy { + /* + * Don't use mmap() at all for reading `packed-refs`. + */ + MMAP_NONE, + + /* + * Can use mmap() for reading `packed-refs`, but the file must + * not remain mmapped. This is the usual option on Windows, + * where you cannot rename a new version of a file onto a file + * that is currently mmapped. + */ + MMAP_TEMPORARY, + + /* + * It is OK to leave the `packed-refs` file mmapped while + * arbitrary other code is running. + */ + MMAP_OK +}; + +#if defined(NO_MMAP) +static enum mmap_strategy mmap_strategy = MMAP_NONE; +#elif defined(MMAP_PREVENTS_DELETE) +static enum mmap_strategy mmap_strategy = MMAP_TEMPORARY; +#else +static enum mmap_strategy mmap_strategy = MMAP_OK; +#endif + +struct packed_ref_store; + +/* + * A `snapshot` represents one snapshot of a `packed-refs` file. + * + * Normally, this will be a mmapped view of the contents of the + * `packed-refs` file at the time the snapshot was created. However, + * if the `packed-refs` file was not sorted, this might point at heap + * memory holding the contents of the `packed-refs` file with its + * records sorted by refname. + * + * `snapshot` instances are reference counted (via + * `acquire_snapshot()` and `release_snapshot()`). This is to prevent + * an instance from disappearing while an iterator is still iterating + * over it. Instances are garbage collected when their `referrers` + * count goes to zero. + * + * The most recent `snapshot`, if available, is referenced by the + * `packed_ref_store`. Its freshness is checked whenever + * `get_snapshot()` is called; if the existing snapshot is obsolete, a + * new snapshot is taken. + */ +struct snapshot { + /* + * A back-pointer to the packed_ref_store with which this + * snapshot is associated: + */ + struct packed_ref_store *refs; + + /* Is the `packed-refs` file currently mmapped? */ + int mmapped; + + /* + * The contents of the `packed-refs` file: + * + * - buf -- a pointer to the start of the memory + * - start -- a pointer to the first byte of actual references + * (i.e., after the header line, if one is present) + * - eof -- a pointer just past the end of the reference + * contents + * + * If the `packed-refs` file was already sorted, `buf` points + * at the mmapped contents of the file. If not, it points at + * heap-allocated memory containing the contents, sorted. If + * there were no contents (e.g., because the file didn't + * exist), `buf`, `start`, and `eof` are all NULL. + */ + char *buf, *start, *eof; + + /* + * What is the peeled state of the `packed-refs` file that + * this snapshot represents? (This is usually determined from + * the file's header.) + */ + enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled; + + /* + * Count of references to this instance, including the pointer + * from `packed_ref_store::snapshot`, if any. The instance + * will not be freed as long as the reference count is + * nonzero. + */ + unsigned int referrers; + + /* + * The metadata of the `packed-refs` file from which this + * snapshot was created, used to tell if the file has been + * replaced since we read it. + */ + struct stat_validity validity; +}; + +/* + * A `ref_store` representing references stored in a `packed-refs` + * file. It implements the `ref_store` interface, though it has some + * limitations: + * + * - It cannot store symbolic references. + * + * - It cannot store reflogs. + * + * - It does not support reference renaming (though it could). + * + * On the other hand, it can be locked outside of a reference + * transaction. In that case, it remains locked even after the + * transaction is done and the new `packed-refs` file is activated. + */ +struct packed_ref_store { + struct ref_store base; + + unsigned int store_flags; + + /* The path of the "packed-refs" file: */ + char *path; + + /* + * A snapshot of the values read from the `packed-refs` file, + * if it might still be current; otherwise, NULL. + */ + struct snapshot *snapshot; + + /* + * 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; +}; + +/* + * Increment the reference count of `*snapshot`. + */ +static void acquire_snapshot(struct snapshot *snapshot) +{ + snapshot->referrers++; +} + +/* + * If the buffer in `snapshot` is active, then either munmap the + * memory and close the file, or free the memory. Then set the buffer + * pointers to NULL. + */ +static void clear_snapshot_buffer(struct snapshot *snapshot) +{ + if (snapshot->mmapped) { + if (munmap(snapshot->buf, snapshot->eof - snapshot->buf)) + die_errno("error ummapping packed-refs file %s", + snapshot->refs->path); + snapshot->mmapped = 0; + } else { + free(snapshot->buf); + } + snapshot->buf = snapshot->start = snapshot->eof = NULL; +} + +/* + * Decrease the reference count of `*snapshot`. If it goes to zero, + * free `*snapshot` and return true; otherwise return false. + */ +static int release_snapshot(struct snapshot *snapshot) +{ + if (!--snapshot->referrers) { + stat_validity_clear(&snapshot->validity); + clear_snapshot_buffer(snapshot); + free(snapshot); + return 1; + } else { + return 0; + } +} + +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; +} + +/* + * 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_snapshot(struct packed_ref_store *refs) +{ + if (refs->snapshot) { + struct snapshot *snapshot = refs->snapshot; + + refs->snapshot = NULL; + release_snapshot(snapshot); + } +} + +static NORETURN void die_unterminated_line(const char *path, + const char *p, size_t len) +{ + if (len < 80) + die("unterminated line in %s: %.*s", path, (int)len, p); + else + die("unterminated line in %s: %.75s...", path, p); +} + +static NORETURN void die_invalid_line(const char *path, + const char *p, size_t len) +{ + const char *eol = memchr(p, '\n', len); + + if (!eol) + die_unterminated_line(path, p, len); + else if (eol - p < 80) + die("unexpected line in %s: %.*s", path, (int)(eol - p), p); + else + die("unexpected line in %s: %.75s...", path, p); + +} + +struct snapshot_record { + const char *start; + size_t len; +}; + +static int cmp_packed_ref_records(const void *v1, const void *v2) +{ + const struct snapshot_record *e1 = v1, *e2 = v2; + const char *r1 = e1->start + GIT_SHA1_HEXSZ + 1; + const char *r2 = e2->start + GIT_SHA1_HEXSZ + 1; + + while (1) { + if (*r1 == '\n') + return *r2 == '\n' ? 0 : -1; + if (*r1 != *r2) { + if (*r2 == '\n') + return 1; + else + return (unsigned char)*r1 < (unsigned char)*r2 ? -1 : +1; + } + r1++; + r2++; + } +} + +/* + * Compare a snapshot record at `rec` to the specified NUL-terminated + * refname. + */ +static int cmp_record_to_refname(const char *rec, const char *refname) +{ + const char *r1 = rec + GIT_SHA1_HEXSZ + 1; + const char *r2 = refname; + + while (1) { + if (*r1 == '\n') + return *r2 ? -1 : 0; + if (!*r2) + return 1; + if (*r1 != *r2) + return (unsigned char)*r1 < (unsigned char)*r2 ? -1 : +1; + r1++; + r2++; + } +} + +/* + * `snapshot->buf` is not known to be sorted. Check whether it is, and + * if not, sort it into new memory and munmap/free the old storage. + */ +static void sort_snapshot(struct snapshot *snapshot) +{ + struct snapshot_record *records = NULL; + size_t alloc = 0, nr = 0; + int sorted = 1; + const char *pos, *eof, *eol; + size_t len, i; + char *new_buffer, *dst; + + pos = snapshot->start; + eof = snapshot->eof; + + if (pos == eof) + return; + + len = eof - pos; + + /* + * Initialize records based on a crude estimate of the number + * of references in the file (we'll grow it below if needed): + */ + ALLOC_GROW(records, len / 80 + 20, alloc); + + while (pos < eof) { + eol = memchr(pos, '\n', eof - pos); + if (!eol) + /* The safety check should prevent this. */ + BUG("unterminated line found in packed-refs"); + if (eol - pos < GIT_SHA1_HEXSZ + 2) + die_invalid_line(snapshot->refs->path, + pos, eof - pos); + eol++; + if (eol < eof && *eol == '^') { + /* + * Keep any peeled line together with its + * reference: + */ + const char *peeled_start = eol; + + eol = memchr(peeled_start, '\n', eof - peeled_start); + if (!eol) + /* The safety check should prevent this. */ + BUG("unterminated peeled line found in packed-refs"); + eol++; + } + + ALLOC_GROW(records, nr + 1, alloc); + records[nr].start = pos; + records[nr].len = eol - pos; + nr++; + + if (sorted && + nr > 1 && + cmp_packed_ref_records(&records[nr - 2], + &records[nr - 1]) >= 0) + sorted = 0; + + pos = eol; + } + + if (sorted) + goto cleanup; + + /* We need to sort the memory. First we sort the records array: */ + QSORT(records, nr, cmp_packed_ref_records); + + /* + * Allocate a new chunk of memory, and copy the old memory to + * the new in the order indicated by `records` (not bothering + * with the header line): + */ + new_buffer = xmalloc(len); + for (dst = new_buffer, i = 0; i < nr; i++) { + memcpy(dst, records[i].start, records[i].len); + dst += records[i].len; + } + + /* + * Now munmap the old buffer and use the sorted buffer in its + * place: + */ + clear_snapshot_buffer(snapshot); + snapshot->buf = snapshot->start = new_buffer; + snapshot->eof = new_buffer + len; + +cleanup: + free(records); +} + +/* + * Return a pointer to the start of the record that contains the + * character `*p` (which must be within the buffer). If no other + * record start is found, return `buf`. + */ +static const char *find_start_of_record(const char *buf, const char *p) +{ + while (p > buf && (p[-1] != '\n' || p[0] == '^')) + p--; + return p; +} + +/* + * Return a pointer to the start of the record following the record + * that contains `*p`. If none is found before `end`, return `end`. + */ +static const char *find_end_of_record(const char *p, const char *end) +{ + while (++p < end && (p[-1] != '\n' || p[0] == '^')) + ; + return p; +} + +/* + * We want to be able to compare mmapped reference records quickly, + * without totally parsing them. We can do so because the records are + * LF-terminated, and the refname should start exactly (GIT_SHA1_HEXSZ + * + 1) bytes past the beginning of the record. + * + * But what if the `packed-refs` file contains garbage? We're willing + * to tolerate not detecting the problem, as long as we don't produce + * totally garbled output (we can't afford to check the integrity of + * the whole file during every Git invocation). But we do want to be + * sure that we never read past the end of the buffer in memory and + * perform an illegal memory access. + * + * Guarantee that minimum level of safety by verifying that the last + * record in the file is LF-terminated, and that it has at least + * (GIT_SHA1_HEXSZ + 1) characters before the LF. Die if either of + * these checks fails. + */ +static void verify_buffer_safe(struct snapshot *snapshot) +{ + const char *start = snapshot->start; + const char *eof = snapshot->eof; + const char *last_line; + + if (start == eof) + return; + + last_line = find_start_of_record(start, eof - 1); + if (*(eof - 1) != '\n' || eof - last_line < GIT_SHA1_HEXSZ + 2) + die_invalid_line(snapshot->refs->path, + last_line, eof - last_line); +} + +#define SMALL_FILE_SIZE (32*1024) + +/* + * Depending on `mmap_strategy`, either mmap or read the contents of + * the `packed-refs` file into the snapshot. Return 1 if the file + * existed and was read, or 0 if the file was absent or empty. Die on + * errors. + */ +static int load_contents(struct snapshot *snapshot) +{ + int fd; + struct stat st; + size_t size; + ssize_t bytes_read; + + fd = open(snapshot->refs->path, O_RDONLY); + if (fd < 0) { + 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, + * which is its state when initialized with + * zeros. + */ + return 0; + } else { + die_errno("couldn't read %s", snapshot->refs->path); + } + } + + stat_validity_update(&snapshot->validity, fd); + + if (fstat(fd, &st) < 0) + die_errno("couldn't stat %s", snapshot->refs->path); + size = xsize_t(st.st_size); + + if (!size) { + return 0; + } else if (mmap_strategy == MMAP_NONE || size <= SMALL_FILE_SIZE) { + snapshot->buf = xmalloc(size); + bytes_read = read_in_full(fd, snapshot->buf, size); + if (bytes_read < 0 || bytes_read != size) + die_errno("couldn't read %s", snapshot->refs->path); + snapshot->mmapped = 0; + } else { + snapshot->buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0); + snapshot->mmapped = 1; + } + close(fd); + + snapshot->start = snapshot->buf; + snapshot->eof = snapshot->buf + size; + + return 1; +} + +/* + * Find the place in `snapshot->buf` where the start of the record for + * `refname` starts. If `mustexist` is true and the reference doesn't + * exist, then return NULL. If `mustexist` is false and the reference + * doesn't exist, then return the point where that reference would be + * inserted, or `snapshot->eof` (which might be NULL) if it would be + * inserted at the end of the file. In the latter mode, `refname` + * doesn't have to be a proper reference name; for example, one could + * search for "refs/replace/" to find the start of any replace + * references. + * + * The record is sought using a binary search, so `snapshot->buf` must + * be sorted. + */ +static const char *find_reference_location(struct snapshot *snapshot, + const char *refname, int mustexist) +{ + /* + * This is not *quite* a garden-variety binary search, because + * the data we're searching is made up of records, and we + * always need to find the beginning of a record to do a + * comparison. A "record" here is one line for the reference + * itself and zero or one peel lines that start with '^'. Our + * loop invariant is described in the next two comments. + */ + + /* + * A pointer to the character at the start of a record whose + * preceding records all have reference names that come + * *before* `refname`. + */ + const char *lo = snapshot->start; + + /* + * A pointer to a the first character of a record whose + * reference name comes *after* `refname`. + */ + const char *hi = snapshot->eof; + + while (lo != hi) { + const char *mid, *rec; + int cmp; + + mid = lo + (hi - lo) / 2; + rec = find_start_of_record(lo, mid); + cmp = cmp_record_to_refname(rec, refname); + if (cmp < 0) { + lo = find_end_of_record(mid, hi); + } else if (cmp > 0) { + hi = rec; + } else { + return rec; + } + } + + if (mustexist) + return NULL; + else + return lo; +} + +/* + * Create a newly-allocated `snapshot` of the `packed-refs` file in + * its current state 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: + * + * Neither `peeled` nor `fully-peeled`: + * + * 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). + * + * `sorted`: + * + * The references in this file are known to be sorted by refname. + */ +static struct snapshot *create_snapshot(struct packed_ref_store *refs) +{ + struct snapshot *snapshot = xcalloc(1, sizeof(*snapshot)); + int sorted = 0; + + snapshot->refs = refs; + acquire_snapshot(snapshot); + snapshot->peeled = PEELED_NONE; + + if (!load_contents(snapshot)) + return snapshot; + + /* If the file has a header line, process it: */ + if (snapshot->buf < snapshot->eof && *snapshot->buf == '#') { + char *tmp, *p, *eol; + struct string_list traits = STRING_LIST_INIT_NODUP; + + eol = memchr(snapshot->buf, '\n', + snapshot->eof - snapshot->buf); + if (!eol) + die_unterminated_line(refs->path, + snapshot->buf, + snapshot->eof - snapshot->buf); + + tmp = xmemdupz(snapshot->buf, eol - snapshot->buf); + + if (!skip_prefix(tmp, "# pack-refs with:", (const char **)&p)) + die_invalid_line(refs->path, + snapshot->buf, + snapshot->eof - snapshot->buf); + + string_list_split_in_place(&traits, p, ' ', -1); + + if (unsorted_string_list_has_string(&traits, "fully-peeled")) + snapshot->peeled = PEELED_FULLY; + else if (unsorted_string_list_has_string(&traits, "peeled")) + snapshot->peeled = PEELED_TAGS; + + sorted = unsorted_string_list_has_string(&traits, "sorted"); + + /* perhaps other traits later as well */ + + /* The "+ 1" is for the LF character. */ + snapshot->start = eol + 1; + + string_list_clear(&traits, 0); + free(tmp); + } + + verify_buffer_safe(snapshot); + + if (!sorted) { + sort_snapshot(snapshot); + + /* + * Reordering the records might have moved a short one + * to the end of the buffer, so verify the buffer's + * safety again: + */ + verify_buffer_safe(snapshot); + } + + if (mmap_strategy != MMAP_OK && snapshot->mmapped) { + /* + * We don't want to leave the file mmapped, so we are + * forced to make a copy now: + */ + size_t size = snapshot->eof - snapshot->start; + char *buf_copy = xmalloc(size); + + memcpy(buf_copy, snapshot->start, size); + clear_snapshot_buffer(snapshot); + snapshot->buf = snapshot->start = buf_copy; + snapshot->eof = buf_copy + size; + } + + return snapshot; +} + +/* + * Check that `refs->snapshot` (if present) still reflects the + * contents of the `packed-refs` file. If not, clear the snapshot. + */ +static void validate_snapshot(struct packed_ref_store *refs) +{ + if (refs->snapshot && + !stat_validity_check(&refs->snapshot->validity, refs->path)) + clear_snapshot(refs); +} + +/* + * Get the `snapshot` 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()`. This function does *not* increase + * the snapshot's reference count on behalf of the caller. + */ +static struct snapshot *get_snapshot(struct packed_ref_store *refs) +{ + if (!is_lock_file_locked(&refs->lock)) + validate_snapshot(refs); + + if (!refs->snapshot) + refs->snapshot = create_snapshot(refs); + + return refs->snapshot; +} + +static int packed_read_raw_ref(struct ref_store *ref_store, + const char *refname, struct object_id *oid, + struct strbuf *referent, unsigned int *type) +{ + struct packed_ref_store *refs = + packed_downcast(ref_store, REF_STORE_READ, "read_raw_ref"); + struct snapshot *snapshot = get_snapshot(refs); + const char *rec; + + *type = 0; + + rec = find_reference_location(snapshot, refname, 1); + + if (!rec) { + /* refname is not a packed reference. */ + errno = ENOENT; + return -1; + } + + if (get_oid_hex(rec, oid)) + die_invalid_line(refs->path, rec, snapshot->eof - rec); + + *type = REF_ISPACKED; + return 0; +} + +/* + * This value is set in `base.flags` if the peeled value of the + * current reference is known. In that case, `peeled` contains the + * correct peeled value for the reference, which might be `null_oid` + * if the reference is not a tag or if it is broken. + */ +#define REF_KNOWS_PEELED 0x40 + +/* + * An iterator over a snapshot of a `packed-refs` file. + */ +struct packed_ref_iterator { + struct ref_iterator base; + + struct snapshot *snapshot; + + /* The current position in the snapshot's buffer: */ + const char *pos; + + /* The end of the part of the buffer that will be iterated over: */ + const char *eof; + + /* Scratch space for current values: */ + struct object_id oid, peeled; + struct strbuf refname_buf; + + unsigned int flags; +}; + +/* + * Move the iterator to the next record in the snapshot, without + * respect for whether the record is actually required by the current + * iteration. Adjust the fields in `iter` and return `ITER_OK` or + * `ITER_DONE`. This function does not free the iterator in the case + * of `ITER_DONE`. + */ +static int next_record(struct packed_ref_iterator *iter) +{ + const char *p = iter->pos, *eol; + + strbuf_reset(&iter->refname_buf); + + if (iter->pos == iter->eof) + return ITER_DONE; + + iter->base.flags = REF_ISPACKED; + + if (iter->eof - p < GIT_SHA1_HEXSZ + 2 || + parse_oid_hex(p, &iter->oid, &p) || + !isspace(*p++)) + die_invalid_line(iter->snapshot->refs->path, + iter->pos, iter->eof - iter->pos); + + eol = memchr(p, '\n', iter->eof - p); + if (!eol) + die_unterminated_line(iter->snapshot->refs->path, + iter->pos, iter->eof - iter->pos); + + strbuf_add(&iter->refname_buf, p, eol - p); + iter->base.refname = iter->refname_buf.buf; + + if (check_refname_format(iter->base.refname, REFNAME_ALLOW_ONELEVEL)) { + if (!refname_is_safe(iter->base.refname)) + die("packed refname is dangerous: %s", + iter->base.refname); + oidclr(&iter->oid); + iter->base.flags |= REF_BAD_NAME | REF_ISBROKEN; + } + if (iter->snapshot->peeled == PEELED_FULLY || + (iter->snapshot->peeled == PEELED_TAGS && + starts_with(iter->base.refname, "refs/tags/"))) + iter->base.flags |= REF_KNOWS_PEELED; + + iter->pos = eol + 1; + + if (iter->pos < iter->eof && *iter->pos == '^') { + p = iter->pos + 1; + if (iter->eof - p < GIT_SHA1_HEXSZ + 1 || + parse_oid_hex(p, &iter->peeled, &p) || + *p++ != '\n') + die_invalid_line(iter->snapshot->refs->path, + iter->pos, iter->eof - iter->pos); + iter->pos = p; + + /* + * Regardless of what the file header said, we + * definitely know the value of *this* reference. But + * we suppress it if the reference is broken: + */ + if ((iter->base.flags & REF_ISBROKEN)) { + oidclr(&iter->peeled); + iter->base.flags &= ~REF_KNOWS_PEELED; + } else { + iter->base.flags |= REF_KNOWS_PEELED; + } + } else { + oidclr(&iter->peeled); + } + + return ITER_OK; +} + +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 = next_record(iter)) == ITER_OK) { + if (iter->flags & DO_FOR_EACH_PER_WORKTREE_ONLY && + ref_type(iter->base.refname) != REF_TYPE_PER_WORKTREE) + continue; + + if (!(iter->flags & DO_FOR_EACH_INCLUDE_BROKEN) && + !ref_resolves_to_object(iter->base.refname, &iter->oid, + iter->flags)) + continue; + + return ITER_OK; + } + + 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; + + if ((iter->base.flags & REF_KNOWS_PEELED)) { + oidcpy(peeled, &iter->peeled); + return is_null_oid(&iter->peeled) ? -1 : 0; + } else if ((iter->base.flags & (REF_ISBROKEN | REF_ISSYMREF))) { + return -1; + } else { + return !!peel_object(&iter->oid, 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; + + strbuf_release(&iter->refname_buf); + release_snapshot(iter->snapshot); + 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 snapshot *snapshot; + const char *start; + 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"); + + /* + * Note that `get_snapshot()` internally checks whether the + * snapshot is up to date with what is on disk, and re-reads + * it if not. + */ + snapshot = get_snapshot(refs); + + if (prefix && *prefix) + start = find_reference_location(snapshot, prefix, 0); + else + start = snapshot->start; + + if (start == snapshot->eof) + return empty_ref_iterator_begin(); + + iter = xcalloc(1, sizeof(*iter)); + ref_iterator = &iter->base; + base_ref_iterator_init(ref_iterator, &packed_ref_iterator_vtable, 1); + + iter->snapshot = snapshot; + acquire_snapshot(snapshot); + + iter->pos = start; + iter->eof = snapshot->eof; + strbuf_init(&iter->refname_buf, 0); + + iter->base.oid = &iter->oid; + + iter->flags = flags; + + if (prefix && *prefix) + /* Stop iteration after we've gone *past* prefix: */ + ref_iterator = prefix_ref_iterator_begin(ref_iterator, prefix, 0); + + 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 struct object_id *oid, + const struct object_id *peeled) +{ + if (fprintf(fh, "%s %s\n", oid_to_hex(oid), refname) < 0 || + (peeled && fprintf(fh, "^%s\n", oid_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; + + 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_gently(&refs->lock)) { + strbuf_addf(err, "unable to close %s: %s", refs->path, strerror(errno)); + rollback_lock_file(&refs->lock); + return -1; + } + + /* + * Now that we hold the `packed-refs` lock, make sure that our + * snapshot matches the current version of the file. Normally + * `get_snapshot()` does that for us, but that function + * assumes that when the file is locked, any existing snapshot + * is still valid. We've just locked the file, but it might + * have changed the moment *before* we locked it. + */ + validate_snapshot(refs); + + /* + * Now make sure that the packed-refs file as it exists in the + * locked state is loaded into the snapshot: + */ + get_snapshot(refs); + 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); +} + +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. + * + * Note that earlier versions of Git used to parse these traits by + * looking for " trait " in the line. For this reason, the space after + * the colon and the trailing space are required. + */ +static const char PACKED_REFS_HEADER[] = + "# pack-refs with: peeled fully-peeled sorted \n"; + +static int packed_init_db(struct ref_store *ref_store, struct strbuf *err) +{ + /* Nothing to do. */ + return 0; +} + +/* + * Write the packed refs from the current snapshot to the packed-refs + * tempfile, incorporating any changes from `updates`. `updates` must + * be a sorted string list whose keys are the refnames and whose util + * values are `struct ref_update *`. On error, rollback the tempfile, + * write an error message to `err`, and return a nonzero value. + * + * The packfile must be locked before calling this function and will + * remain locked when it is done. + */ +static int write_with_updates(struct packed_ref_store *refs, + struct string_list *updates, + struct strbuf *err) +{ + struct ref_iterator *iter = NULL; + size_t i; + int ok; + FILE *out; + struct strbuf sb = STRBUF_INIT; + char *packed_refs_path; + + if (!is_lock_file_locked(&refs->lock)) + die("BUG: write_with_updates() called while 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); + free(packed_refs_path); + refs->tempfile = create_tempfile(sb.buf); + if (!refs->tempfile) { + strbuf_addf(err, "unable to create file %s: %s", + sb.buf, strerror(errno)); + strbuf_release(&sb); + return -1; + } + 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) + goto write_error; + + /* + * We iterate in parallel through the current list of refs and + * the list of updates, processing an entry from at least one + * of the lists each time through the loop. When the current + * list of refs is exhausted, set iter to NULL. When the list + * of updates is exhausted, leave i set to updates->nr. + */ + iter = packed_ref_iterator_begin(&refs->base, "", + DO_FOR_EACH_INCLUDE_BROKEN); + if ((ok = ref_iterator_advance(iter)) != ITER_OK) + iter = NULL; + + i = 0; + + while (iter || i < updates->nr) { + struct ref_update *update = NULL; + int cmp; + + if (i >= updates->nr) { + cmp = -1; + } else { + update = updates->items[i].util; + + if (!iter) + cmp = +1; + else + cmp = strcmp(iter->refname, update->refname); + } + + if (!cmp) { + /* + * There is both an old value and an update + * for this reference. Check the old value if + * necessary: + */ + if ((update->flags & REF_HAVE_OLD)) { + if (is_null_oid(&update->old_oid)) { + strbuf_addf(err, "cannot update ref '%s': " + "reference already exists", + update->refname); + goto error; + } else if (oidcmp(&update->old_oid, iter->oid)) { + strbuf_addf(err, "cannot update ref '%s': " + "is at %s but expected %s", + update->refname, + oid_to_hex(iter->oid), + oid_to_hex(&update->old_oid)); + goto error; + } + } + + /* Now figure out what to use for the new value: */ + if ((update->flags & REF_HAVE_NEW)) { + /* + * The update takes precedence. Skip + * the iterator over the unneeded + * value. + */ + if ((ok = ref_iterator_advance(iter)) != ITER_OK) + iter = NULL; + cmp = +1; + } else { + /* + * The update doesn't actually want to + * change anything. We're done with it. + */ + i++; + cmp = -1; + } + } else if (cmp > 0) { + /* + * There is no old value but there is an + * update for this reference. Make sure that + * the update didn't expect an existing value: + */ + if ((update->flags & REF_HAVE_OLD) && + !is_null_oid(&update->old_oid)) { + strbuf_addf(err, "cannot update ref '%s': " + "reference is missing but expected %s", + update->refname, + oid_to_hex(&update->old_oid)); + goto error; + } + } + + if (cmp < 0) { + /* Pass the old reference through. */ + + struct object_id peeled; + int peel_error = ref_iterator_peel(iter, &peeled); + + if (write_packed_entry(out, iter->refname, + iter->oid, + peel_error ? NULL : &peeled)) + goto write_error; + + if ((ok = ref_iterator_advance(iter)) != ITER_OK) + iter = NULL; + } else if (is_null_oid(&update->new_oid)) { + /* + * The update wants to delete the reference, + * and the reference either didn't exist or we + * have already skipped it. So we're done with + * the update (and don't have to write + * anything). + */ + i++; + } else { + struct object_id peeled; + int peel_error = peel_object(&update->new_oid, + &peeled); + + if (write_packed_entry(out, update->refname, + &update->new_oid, + peel_error ? NULL : &peeled)) + goto write_error; + + i++; + } + } + + if (ok != ITER_DONE) { + strbuf_addstr(err, "unable to write packed-refs file: " + "error iterating over old contents"); + goto error; + } + + if (close_tempfile_gently(refs->tempfile)) { + strbuf_addf(err, "error closing file %s: %s", + get_tempfile_path(refs->tempfile), + strerror(errno)); + strbuf_release(&sb); + delete_tempfile(&refs->tempfile); + return -1; + } + + return 0; + +write_error: + strbuf_addf(err, "error writing to %s: %s", + get_tempfile_path(refs->tempfile), strerror(errno)); + +error: + if (iter) + ref_iterator_abort(iter); + + delete_tempfile(&refs->tempfile); + return -1; +} + +int is_packed_transaction_needed(struct ref_store *ref_store, + struct ref_transaction *transaction) +{ + struct packed_ref_store *refs = packed_downcast( + ref_store, + REF_STORE_READ, + "is_packed_transaction_needed"); + struct strbuf referent = STRBUF_INIT; + size_t i; + int ret; + + if (!is_lock_file_locked(&refs->lock)) + BUG("is_packed_transaction_needed() called while unlocked"); + + /* + * We're only going to bother returning false for the common, + * trivial case that references are only being deleted, their + * old values are not being checked, and the old `packed-refs` + * file doesn't contain any of those reference(s). This gives + * false positives for some other cases that could + * theoretically be optimized away: + * + * 1. It could be that the old value is being verified without + * setting a new value. In this case, we could verify the + * old value here and skip the update if it agrees. If it + * disagrees, we could either let the update go through + * (the actual commit would re-detect and report the + * problem), or come up with a way of reporting such an + * error to *our* caller. + * + * 2. It could be that a new value is being set, but that it + * is identical to the current packed value of the + * reference. + * + * Neither of these cases will come up in the current code, + * because the only caller of this function passes to it a + * transaction that only includes `delete` updates with no + * `old_id`. Even if that ever changes, false positives only + * cause an optimization to be missed; they do not affect + * correctness. + */ + + /* + * Start with the cheap checks that don't require old + * reference values to be read: + */ + for (i = 0; i < transaction->nr; i++) { + struct ref_update *update = transaction->updates[i]; + + if (update->flags & REF_HAVE_OLD) + /* Have to check the old value -> needed. */ + return 1; + + if ((update->flags & REF_HAVE_NEW) && !is_null_oid(&update->new_oid)) + /* Have to set a new value -> needed. */ + return 1; + } + + /* + * The transaction isn't checking any old values nor is it + * setting any nonzero new values, so it still might be able + * to be skipped. Now do the more expensive check: the update + * is needed if any of the updates is a delete, and the old + * `packed-refs` file contains a value for that reference. + */ + ret = 0; + for (i = 0; i < transaction->nr; i++) { + struct ref_update *update = transaction->updates[i]; + unsigned int type; + struct object_id oid; + + if (!(update->flags & REF_HAVE_NEW)) + /* + * This reference isn't being deleted -> not + * needed. + */ + continue; + + if (!refs_read_raw_ref(ref_store, update->refname, + &oid, &referent, &type) || + errno != ENOENT) { + /* + * We have to actually delete that reference + * -> this transaction is needed. + */ + ret = 1; + break; + } + } + + strbuf_release(&referent); + return ret; +} + +struct packed_transaction_backend_data { + /* True iff the transaction owns the packed-refs lock. */ + int own_lock; + + struct string_list updates; +}; + +static void packed_transaction_cleanup(struct packed_ref_store *refs, + struct ref_transaction *transaction) +{ + struct packed_transaction_backend_data *data = transaction->backend_data; + + if (data) { + string_list_clear(&data->updates, 0); + + if (is_tempfile_active(refs->tempfile)) + delete_tempfile(&refs->tempfile); + + if (data->own_lock && is_lock_file_locked(&refs->lock)) { + packed_refs_unlock(&refs->base); + data->own_lock = 0; + } + + free(data); + transaction->backend_data = NULL; + } + + transaction->state = REF_TRANSACTION_CLOSED; +} + +static int packed_transaction_prepare(struct ref_store *ref_store, + struct ref_transaction *transaction, + struct strbuf *err) +{ + struct packed_ref_store *refs = packed_downcast( + ref_store, + REF_STORE_READ | REF_STORE_WRITE | REF_STORE_ODB, + "ref_transaction_prepare"); + struct packed_transaction_backend_data *data; + size_t i; + int ret = TRANSACTION_GENERIC_ERROR; + + /* + * Note that we *don't* skip transactions with zero updates, + * because such a transaction might be executed for the side + * effect of ensuring that all of the references are peeled or + * ensuring that the `packed-refs` file is sorted. If the + * caller wants to optimize away empty transactions, it should + * do so itself. + */ + + data = xcalloc(1, sizeof(*data)); + string_list_init(&data->updates, 0); + + transaction->backend_data = data; + + /* + * Stick the updates in a string list by refname so that we + * can sort them: + */ + for (i = 0; i < transaction->nr; i++) { + struct ref_update *update = transaction->updates[i]; + struct string_list_item *item = + string_list_append(&data->updates, update->refname); + + /* Store a pointer to update in item->util: */ + item->util = update; + } + string_list_sort(&data->updates); + + if (ref_update_reject_duplicates(&data->updates, err)) + goto failure; + + if (!is_lock_file_locked(&refs->lock)) { + if (packed_refs_lock(ref_store, 0, err)) + goto failure; + data->own_lock = 1; + } + + if (write_with_updates(refs, &data->updates, err)) + goto failure; + + transaction->state = REF_TRANSACTION_PREPARED; + return 0; + +failure: + packed_transaction_cleanup(refs, transaction); + return ret; +} + +static int packed_transaction_abort(struct ref_store *ref_store, + struct ref_transaction *transaction, + struct strbuf *err) +{ + struct packed_ref_store *refs = packed_downcast( + ref_store, + REF_STORE_READ | REF_STORE_WRITE | REF_STORE_ODB, + "ref_transaction_abort"); + + packed_transaction_cleanup(refs, transaction); + return 0; +} + +static int packed_transaction_finish(struct ref_store *ref_store, + struct ref_transaction *transaction, + struct strbuf *err) +{ + struct packed_ref_store *refs = packed_downcast( + ref_store, + REF_STORE_READ | REF_STORE_WRITE | REF_STORE_ODB, + "ref_transaction_finish"); + int ret = TRANSACTION_GENERIC_ERROR; + char *packed_refs_path; + + clear_snapshot(refs); + + packed_refs_path = get_locked_file_path(&refs->lock); + if (rename_tempfile(&refs->tempfile, packed_refs_path)) { + strbuf_addf(err, "error replacing %s: %s", + refs->path, strerror(errno)); + goto cleanup; + } + + ret = 0; + +cleanup: + free(packed_refs_path); + packed_transaction_cleanup(refs, transaction); + return ret; +} + +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) +{ + struct packed_ref_store *refs = + packed_downcast(ref_store, REF_STORE_WRITE, "delete_refs"); + struct strbuf err = STRBUF_INIT; + struct ref_transaction *transaction; + struct string_list_item *item; + int ret; + + (void)refs; /* We need the check above, but don't use the variable */ + + if (!refnames->nr) + return 0; + + /* + * Since we don't check the references' old_oids, the + * individual updates can't fail, so we can pack all of the + * updates into a single transaction. + */ + + transaction = ref_store_transaction_begin(ref_store, &err); + if (!transaction) + return -1; + + for_each_string_list_item(item, refnames) { + if (ref_transaction_delete(transaction, item->string, NULL, + flags, msg, &err)) { + warning(_("could not delete reference %s: %s"), + item->string, err.buf); + strbuf_reset(&err); + } + } + + ret = ref_transaction_commit(transaction, &err); + + if (ret) { + 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); + } + + ref_transaction_free(transaction); + strbuf_release(&err); + return ret; +} + +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 int packed_copy_ref(struct ref_store *ref_store, + const char *oldrefname, const char *newrefname, + const char *logmsg) +{ + die("BUG: packed reference store does not support copying 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 struct object_id *oid, + 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_create_symref, + packed_delete_refs, + packed_rename_ref, + packed_copy_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 +}; diff --git a/refs/packed-backend.h b/refs/packed-backend.h new file mode 100644 index 0000000000..640245d3b9 --- /dev/null +++ b/refs/packed-backend.h @@ -0,0 +1,35 @@ +#ifndef REFS_PACKED_BACKEND_H +#define REFS_PACKED_BACKEND_H + +/* + * Support for storing references in a `packed-refs` file. + * + * Note that this backend doesn't check for D/F conflicts, because it + * doesn't care about them. But usually it should be wrapped in a + * `files_ref_store` that prevents D/F conflicts from being created, + * even among packed refs. + */ + +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); + +/* + * Return true if `transaction` really needs to be carried out against + * the specified packed_ref_store, or false if it can be skipped + * (i.e., because it is an obvious NOOP). `ref_store` must be locked + * before calling this function. + */ +int is_packed_transaction_needed(struct ref_store *ref_store, + struct ref_transaction *transaction); + +#endif /* REFS_PACKED_BACKEND_H */ diff --git a/refs/ref-cache.c b/refs/ref-cache.c index 6059362f1d..e90bd3e727 100644 --- a/refs/ref-cache.c +++ b/refs/ref-cache.c @@ -32,17 +32,12 @@ struct ref_dir *get_ref_dir(struct ref_entry *entry) } struct ref_entry *create_ref_entry(const char *refname, - const unsigned char *sha1, int flag, - int check_name) + const struct object_id *oid, int flag) { struct ref_entry *ref; - if (check_name && - check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) - die("Reference has invalid format: '%s'", refname); FLEX_ALLOC_STR(ref, name, refname); - hashcpy(ref->u.value.oid.hash, sha1); - oidclr(&ref->u.value.peeled); + oidcpy(&ref->u.value.oid, oid); ref->flag = flag; return ref; } @@ -86,9 +81,8 @@ static void clear_ref_dir(struct ref_dir *dir) int i; for (i = 0; i < dir->nr; i++) free_ref_entry(dir->entries[i]); - free(dir->entries); + FREE_AND_NULL(dir->entries); dir->sorted = dir->nr = dir->alloc = 0; - dir->entries = NULL; } struct ref_entry *create_dir_entry(struct ref_cache *cache, @@ -244,10 +238,8 @@ int remove_entry_from_dir(struct ref_dir *dir, const char *refname) return -1; entry = dir->entries[entry_index]; - memmove(&dir->entries[entry_index], - &dir->entries[entry_index + 1], - (dir->nr - entry_index - 1) * sizeof(*dir->entries) - ); + MOVE_ARRAY(&dir->entries[entry_index], + &dir->entries[entry_index + 1], dir->nr - entry_index - 1); dir->nr--; if (dir->sorted > entry_index) dir->sorted--; @@ -266,8 +258,8 @@ int add_ref_entry(struct ref_dir *dir, struct ref_entry *ref) /* * Emit a warning and return true iff ref1 and ref2 have the same name - * and the same sha1. Die if they have the same name but different - * sha1s. + * and the same oid. Die if they have the same name but different + * oids. */ static int is_dup_ref(const struct ref_entry *ref1, const struct ref_entry *ref2) { @@ -316,11 +308,42 @@ static void sort_ref_dir(struct ref_dir *dir) dir->sorted = dir->nr = i; } +enum prefix_state { + /* All refs within the directory would match prefix: */ + PREFIX_CONTAINS_DIR, + + /* Some, but not all, refs within the directory might match prefix: */ + PREFIX_WITHIN_DIR, + + /* No refs within the directory could possibly match prefix: */ + PREFIX_EXCLUDES_DIR +}; + +/* + * Return a `prefix_state` constant describing the relationship + * between the directory with the specified `dirname` and `prefix`. + */ +static enum prefix_state overlaps_prefix(const char *dirname, + const char *prefix) +{ + while (*prefix && *dirname == *prefix) { + dirname++; + prefix++; + } + if (!*prefix) + return PREFIX_CONTAINS_DIR; + else if (!*dirname) + return PREFIX_WITHIN_DIR; + else + return PREFIX_EXCLUDES_DIR; +} + /* - * Load all of the refs from `dir` (recursively) into our in-memory - * cache. + * Load all of the refs from `dir` (recursively) that could possibly + * contain references matching `prefix` into our in-memory cache. If + * `prefix` is NULL, prime unconditionally. */ -static void prime_ref_dir(struct ref_dir *dir) +static void prime_ref_dir(struct ref_dir *dir, const char *prefix) { /* * The hard work of loading loose refs is done by get_ref_dir(), so we @@ -331,8 +354,29 @@ static void prime_ref_dir(struct ref_dir *dir) int i; for (i = 0; i < dir->nr; i++) { struct ref_entry *entry = dir->entries[i]; - if (entry->flag & REF_DIR) - prime_ref_dir(get_ref_dir(entry)); + if (!(entry->flag & REF_DIR)) { + /* Not a directory; no need to recurse. */ + } else if (!prefix) { + /* Recurse in any case: */ + prime_ref_dir(get_ref_dir(entry), NULL); + } else { + switch (overlaps_prefix(entry->name, prefix)) { + case PREFIX_CONTAINS_DIR: + /* + * Recurse, and from here down we + * don't have to check the prefix + * anymore: + */ + prime_ref_dir(get_ref_dir(entry), NULL); + break; + case PREFIX_WITHIN_DIR: + prime_ref_dir(get_ref_dir(entry), prefix); + break; + case PREFIX_EXCLUDES_DIR: + /* No need to prime this directory. */ + break; + } + } } } @@ -347,6 +391,8 @@ struct cache_ref_iterator_level { */ struct ref_dir *dir; + enum prefix_state prefix_state; + /* * The index of the current entry within dir (which might * itself be a directory). If index == -1, then the iteration @@ -374,6 +420,13 @@ struct cache_ref_iterator { size_t levels_alloc; /* + * Only include references with this prefix in the iteration. + * The prefix is matched textually, without regard for path + * component boundaries. + */ + const char *prefix; + + /* * A stack of levels. levels[0] is the uppermost level that is * being iterated over in this iteration. (This is not * necessary the top level in the references hierarchy. If we @@ -394,6 +447,7 @@ static int cache_ref_iterator_advance(struct ref_iterator *ref_iterator) &iter->levels[iter->levels_nr - 1]; struct ref_dir *dir = level->dir; struct ref_entry *entry; + enum prefix_state entry_prefix_state; if (level->index == -1) sort_ref_dir(dir); @@ -408,6 +462,14 @@ static int cache_ref_iterator_advance(struct ref_iterator *ref_iterator) entry = dir->entries[level->index]; + if (level->prefix_state == PREFIX_WITHIN_DIR) { + entry_prefix_state = overlaps_prefix(entry->name, iter->prefix); + if (entry_prefix_state == PREFIX_EXCLUDES_DIR) + continue; + } else { + entry_prefix_state = level->prefix_state; + } + if (entry->flag & REF_DIR) { /* push down a level */ ALLOC_GROW(iter->levels, iter->levels_nr + 1, @@ -415,6 +477,7 @@ static int cache_ref_iterator_advance(struct ref_iterator *ref_iterator) level = &iter->levels[iter->levels_nr++]; level->dir = get_ref_dir(entry); + level->prefix_state = entry_prefix_state; level->index = -1; } else { iter->base.refname = entry->name; @@ -425,49 +488,10 @@ static int cache_ref_iterator_advance(struct ref_iterator *ref_iterator) } } -enum peel_status peel_entry(struct ref_entry *entry, int repeel) -{ - enum peel_status status; - - if (entry->flag & REF_KNOWS_PEELED) { - if (repeel) { - entry->flag &= ~REF_KNOWS_PEELED; - oidclr(&entry->u.value.peeled); - } else { - return is_null_oid(&entry->u.value.peeled) ? - PEEL_NON_TAG : PEEL_PEELED; - } - } - if (entry->flag & REF_ISBROKEN) - return PEEL_BROKEN; - if (entry->flag & REF_ISSYMREF) - return PEEL_IS_SYMREF; - - status = peel_object(entry->u.value.oid.hash, entry->u.value.peeled.hash); - if (status == PEEL_PEELED || status == PEEL_NON_TAG) - entry->flag |= REF_KNOWS_PEELED; - return status; -} - static int cache_ref_iterator_peel(struct ref_iterator *ref_iterator, struct object_id *peeled) { - struct cache_ref_iterator *iter = - (struct cache_ref_iterator *)ref_iterator; - struct cache_ref_iterator_level *level; - struct ref_entry *entry; - - level = &iter->levels[iter->levels_nr - 1]; - - if (level->index == -1) - die("BUG: peel called before advance for cache iterator"); - - entry = level->dir->entries[level->index]; - - if (peel_entry(entry, 0)) - return -1; - oidcpy(peeled, &entry->u.value.peeled); - return 0; + return peel_object(ref_iterator->oid, peeled); } static int cache_ref_iterator_abort(struct ref_iterator *ref_iterator) @@ -475,6 +499,7 @@ static int cache_ref_iterator_abort(struct ref_iterator *ref_iterator) struct cache_ref_iterator *iter = (struct cache_ref_iterator *)ref_iterator; + free((char *)iter->prefix); free(iter->levels); base_ref_iterator_free(ref_iterator); return ITER_DONE; @@ -500,14 +525,14 @@ struct ref_iterator *cache_ref_iterator_begin(struct ref_cache *cache, dir = find_containing_dir(dir, prefix, 0); if (!dir) /* There's nothing to iterate over. */ - return empty_ref_iterator_begin(); + return empty_ref_iterator_begin(); if (prime_dir) - prime_ref_dir(dir); + prime_ref_dir(dir, prefix); iter = xcalloc(1, sizeof(*iter)); ref_iterator = &iter->base; - base_ref_iterator_init(ref_iterator, &cache_ref_iterator_vtable); + base_ref_iterator_init(ref_iterator, &cache_ref_iterator_vtable, 1); ALLOC_GROW(iter->levels, 10, iter->levels_alloc); iter->levels_nr = 1; @@ -515,9 +540,12 @@ struct ref_iterator *cache_ref_iterator_begin(struct ref_cache *cache, level->index = -1; level->dir = dir; - if (prefix && *prefix) - ref_iterator = prefix_ref_iterator_begin(ref_iterator, - prefix, 0); + if (prefix && *prefix) { + iter->prefix = xstrdup(prefix); + level->prefix_state = PREFIX_WITHIN_DIR; + } else { + level->prefix_state = PREFIX_CONTAINS_DIR; + } return ref_iterator; } diff --git a/refs/ref-cache.h b/refs/ref-cache.h index ffdc54f3f0..eda65e73ed 100644 --- a/refs/ref-cache.h +++ b/refs/ref-cache.h @@ -38,14 +38,6 @@ struct ref_value { * referred to by the last reference in the symlink chain. */ struct object_id oid; - - /* - * If REF_KNOWS_PEELED, then this field holds the peeled value - * of this reference, or null if the reference is known not to - * be peelable. See the documentation for peel_ref() for an - * exact definition of "peelable". - */ - struct object_id peeled; }; /* @@ -97,21 +89,14 @@ struct ref_dir { * public values; see refs.h. */ -/* - * The field ref_entry->u.value.peeled of this value entry contains - * the correct peeled value for the reference, which might be - * null_sha1 if the reference is not a tag or if it is broken. - */ -#define REF_KNOWS_PEELED 0x10 - /* ref_entry represents a directory of references */ -#define REF_DIR 0x20 +#define REF_DIR 0x10 /* * Entry has not yet been read from disk (used only for REF_DIR * entries representing loose references) */ -#define REF_INCOMPLETE 0x40 +#define REF_INCOMPLETE 0x20 /* * A ref_entry represents either a reference or a "subdirectory" of @@ -185,8 +170,7 @@ struct ref_entry *create_dir_entry(struct ref_cache *cache, int incomplete); struct ref_entry *create_ref_entry(const char *refname, - const unsigned char *sha1, int flag, - int check_name); + const struct object_id *oid, int flag); /* * Return a pointer to a new `ref_cache`. Its top-level starts out @@ -194,7 +178,8 @@ struct ref_entry *create_ref_entry(const char *refname, * function called to fill in incomplete directories in the * `ref_cache` when they are accessed. If it is NULL, then the whole * `ref_cache` must be filled (including clearing its directories' - * `REF_INCOMPLETE` bits) before it is used. + * `REF_INCOMPLETE` bits) before it is used, and `refs` can be NULL, + * too. */ struct ref_cache *create_ref_cache(struct ref_store *refs, fill_ref_dir_fn *fill_ref_dir); @@ -245,23 +230,11 @@ struct ref_entry *find_ref_entry(struct ref_dir *dir, const char *refname); * Start iterating over references in `cache`. If `prefix` is * specified, only include references whose names start with that * prefix. If `prime_dir` is true, then fill any incomplete - * directories before beginning the iteration. + * directories before beginning the iteration. The output is ordered + * by refname. */ struct ref_iterator *cache_ref_iterator_begin(struct ref_cache *cache, const char *prefix, int prime_dir); -/* - * Peel the entry (if possible) and return its new peel_status. If - * repeel is true, re-peel the entry even if there is an old peeled - * value that is already stored in it. - * - * It is OK to call this function with a packed reference entry that - * might be stale and might even refer to an object that has since - * been garbage-collected. In such a case, if the entry has - * REF_KNOWS_PEELED then leave the status unchanged and return - * PEEL_PEELED or PEEL_NON_TAG; otherwise, return PEEL_INVALID. - */ -enum peel_status peel_entry(struct ref_entry *entry, int repeel); - #endif /* REFS_REF_CACHE_H */ diff --git a/refs/refs-internal.h b/refs/refs-internal.h index 3d46131efb..dd834314bd 100644 --- a/refs/refs-internal.h +++ b/refs/refs-internal.h @@ -8,58 +8,28 @@ */ /* - * Flag passed to lock_ref_sha1_basic() telling it to tolerate broken - * refs (i.e., because the reference is about to be deleted anyway). + * The following flags can appear in `ref_update::flags`. Their + * numerical values must not conflict with those of REF_NO_DEREF and + * REF_FORCE_CREATE_REFLOG, which are also stored in + * `ref_update::flags`. */ -#define REF_DELETING 0x02 /* - * Used as a flag in ref_update::flags when a loose ref is being - * pruned. This flag must only be used when REF_NODEREF is set. + * The reference should be updated to new_oid. */ -#define REF_ISPRUNING 0x04 +#define REF_HAVE_NEW (1 << 2) /* - * Used as a flag in ref_update::flags when the reference should be - * updated to new_sha1. + * The current reference's value should be checked to make sure that + * it agrees with old_oid. */ -#define REF_HAVE_NEW 0x08 +#define REF_HAVE_OLD (1 << 3) /* - * Used as a flag in ref_update::flags when old_sha1 should be - * checked. + * Return the length of time to retry acquiring a loose reference lock + * before giving up, in milliseconds: */ -#define REF_HAVE_OLD 0x10 - -/* - * Used as a flag in ref_update::flags when the lockfile needs to be - * committed. - */ -#define REF_NEEDS_COMMIT 0x20 - -/* - * 0x40 is REF_FORCE_CREATE_REFLOG, so skip it if you're adding a - * value to ref_update::flags - */ - -/* - * Used as a flag in ref_update::flags when we want to log a ref - * update but not actually perform it. This is used when a symbolic - * ref update is split up. - */ -#define REF_LOG_ONLY 0x80 - -/* - * Internal flag, meaning that the containing ref_update was via an - * update to HEAD. - */ -#define REF_UPDATE_VIA_HEAD 0x100 - -/* - * Used as a flag in ref_update::flags when the loose reference has - * been deleted. - */ -#define REF_DELETED_LOOSE 0x200 +long get_files_ref_lock_timeout_ms(void); /* * Return true iff refname is minimally safe. "Safe" here means that @@ -77,6 +47,15 @@ */ 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, @@ -105,11 +84,11 @@ enum peel_status { /* * Peel the named object; i.e., if the object is a tag, resolve the * tag recursively until a non-tag is found. If successful, store the - * result to sha1 and return PEEL_PEELED. If the object is not a tag + * result to oid and return PEEL_PEELED. If the object is not a tag * or is not valid, return PEEL_NON_TAG or PEEL_INVALID, respectively, - * and leave sha1 unchanged. + * and leave oid unchanged. */ -enum peel_status peel_object(const unsigned char *name, unsigned char *sha1); +enum peel_status peel_object(const struct object_id *name, struct object_id *oid); /* * Copy the reflog message msg to buf, which has been allocated sufficiently @@ -119,30 +98,29 @@ enum peel_status peel_object(const unsigned char *name, unsigned char *sha1); int copy_reflog_msg(char *buf, const char *msg); /** - * Information needed for a single ref update. Set new_sha1 to the new - * value or to null_sha1 to delete the ref. To check the old value - * while the ref is locked, set (flags & REF_HAVE_OLD) and set - * old_sha1 to the old value, or to null_sha1 to ensure the ref does - * not exist before update. + * Information needed for a single ref update. Set new_oid to the new + * value or to null_oid to delete the ref. To check the old value + * while the ref is locked, set (flags & REF_HAVE_OLD) and set old_oid + * to the old value, or to null_oid to ensure the ref does not exist + * before update. */ struct ref_update { - /* - * If (flags & REF_HAVE_NEW), set the reference to this value: + * If (flags & REF_HAVE_NEW), set the reference to this value + * (or delete it, if `new_oid` is `null_oid`). */ - unsigned char new_sha1[20]; + struct object_id new_oid; /* * If (flags & REF_HAVE_OLD), check that the reference - * previously had this value: + * previously had this value (or didn't previously exist, if + * `old_oid` is `null_oid`). */ - unsigned char old_sha1[20]; + struct object_id old_oid; /* - * One or more of REF_HAVE_NEW, REF_HAVE_OLD, REF_NODEREF, - * REF_DELETING, REF_ISPRUNING, REF_LOG_ONLY, - * REF_UPDATE_VIA_HEAD, REF_NEEDS_COMMIT, and - * REF_DELETED_LOOSE: + * One or more of REF_NO_DEREF, REF_FORCE_CREATE_REFLOG, + * REF_HAVE_NEW, REF_HAVE_OLD, or backend-specific flags. */ unsigned int flags; @@ -166,36 +144,54 @@ struct ref_update { }; int refs_read_raw_ref(struct ref_store *ref_store, - const char *refname, unsigned char *sha1, + const char *refname, struct object_id *oid, struct strbuf *referent, unsigned int *type); /* + * Write an error to `err` and return a nonzero value iff the same + * refname appears multiple times in `refnames`. `refnames` must be + * sorted on entry to this function. + */ +int ref_update_reject_duplicates(struct string_list *refnames, + struct strbuf *err); + +/* * Add a ref_update with the specified properties to transaction, and * return a pointer to the new object. This function does not verify - * that refname is well-formed. new_sha1 and old_sha1 are only + * that refname is well-formed. new_oid and old_oid are only * dereferenced if the REF_HAVE_NEW and REF_HAVE_OLD bits, * respectively, are set in flags. */ struct ref_update *ref_transaction_add_update( struct ref_transaction *transaction, const char *refname, unsigned int flags, - const unsigned char *new_sha1, - const unsigned char *old_sha1, + const struct object_id *new_oid, + const struct object_id *old_oid, const char *msg); /* * Transaction states. - * OPEN: The transaction is in a valid state and can accept new updates. - * An OPEN transaction can be committed. - * CLOSED: A closed transaction is no longer active and no other operations - * than free can be used on it in this state. - * A transaction can either become closed by successfully committing - * an active transaction or if there is a failure while building - * the transaction thus rendering it failed/inactive. + * + * OPEN: The transaction is initialized and new updates can still be + * added to it. An OPEN transaction can be prepared, + * committed, freed, or aborted (freeing and aborting an open + * transaction are equivalent). + * + * PREPARED: ref_transaction_prepare(), which locks all of the + * references involved in the update and checks that the + * update has no errors, has been called successfully for the + * transaction. A PREPARED transaction can be committed or + * aborted. + * + * CLOSED: The transaction is no longer active. A transaction becomes + * CLOSED if there is a failure while building the transaction + * or if a transaction is committed or aborted. A CLOSED + * transaction can only be freed. */ enum ref_transaction_state { - REF_TRANSACTION_OPEN = 0, - REF_TRANSACTION_CLOSED = 1 + REF_TRANSACTION_OPEN = 0, + REF_TRANSACTION_PREPARED = 1, + REF_TRANSACTION_CLOSED = 2 }; /* @@ -209,6 +205,7 @@ struct ref_transaction { size_t alloc; size_t nr; enum ref_transaction_state state; + void *backend_data; }; /* @@ -295,6 +292,13 @@ int refs_rename_ref_available(struct ref_store *refs, */ struct ref_iterator { struct ref_iterator_vtable *vtable; + + /* + * Does this `ref_iterator` iterate over references in order + * by refname? + */ + unsigned int ordered : 1; + const char *refname; const struct object_id *oid; unsigned int flags; @@ -340,7 +344,7 @@ int is_empty_ref_iterator(struct ref_iterator *ref_iterator); * which the refname begins with prefix. If trim is non-zero, then * trim that many characters off the beginning of each refname. flags * can be DO_FOR_EACH_INCLUDE_BROKEN to include broken references in - * the iteration. + * the iteration. The output is ordered by refname. */ struct ref_iterator *refs_ref_iterator_begin( struct ref_store *refs, @@ -366,9 +370,11 @@ typedef enum iterator_selection ref_iterator_select_fn( * Iterate over the entries from iter0 and iter1, with the values * interleaved as directed by the select function. The iterator takes * ownership of iter0 and iter1 and frees them when the iteration is - * over. + * over. A derived class should set `ordered` to 1 or 0 based on + * whether it generates its output in order by reference name. */ struct ref_iterator *merge_ref_iterator_begin( + int ordered, struct ref_iterator *iter0, struct ref_iterator *iter1, ref_iterator_select_fn *select, void *cb_data); @@ -397,6 +403,8 @@ struct ref_iterator *overlay_ref_iterator_begin( * As an convenience to callers, if prefix is the empty string and * trim is zero, this function returns iter0 directly, without * wrapping it. + * + * The resulting ref_iterator is ordered if iter0 is. */ struct ref_iterator *prefix_ref_iterator_begin(struct ref_iterator *iter0, const char *prefix, @@ -407,11 +415,14 @@ struct ref_iterator *prefix_ref_iterator_begin(struct ref_iterator *iter0, /* * Base class constructor for ref_iterators. Initialize the * ref_iterator part of iter, setting its vtable pointer as specified. + * `ordered` should be set to 1 if the iterator will iterate over + * references in order by refname; otherwise it should be set to 0. * This is meant to be called only by the initializers of derived * classes. */ void base_ref_iterator_init(struct ref_iterator *iter, - struct ref_iterator_vtable *vtable); + struct ref_iterator_vtable *vtable, + int ordered); /* * Base class destructor for ref_iterators. Destroy the ref_iterator @@ -482,6 +493,10 @@ struct ref_store; #define REF_STORE_WRITE (1 << 1) /* can perform update operations */ #define REF_STORE_ODB (1 << 2) /* has access to object database */ #define REF_STORE_MAIN (1 << 3) +#define REF_STORE_ALL_CAPS (REF_STORE_READ | \ + REF_STORE_WRITE | \ + REF_STORE_ODB | \ + REF_STORE_MAIN) /* * Initialize the ref_store for the specified gitdir. These functions @@ -493,27 +508,42 @@ typedef struct ref_store *ref_store_init_fn(const char *gitdir, typedef int ref_init_db_fn(struct ref_store *refs, struct strbuf *err); +typedef int ref_transaction_prepare_fn(struct ref_store *refs, + struct ref_transaction *transaction, + struct strbuf *err); + +typedef int ref_transaction_finish_fn(struct ref_store *refs, + struct ref_transaction *transaction, + struct strbuf *err); + +typedef int ref_transaction_abort_fn(struct ref_store *refs, + struct ref_transaction *transaction, + struct strbuf *err); + typedef int ref_transaction_commit_fn(struct ref_store *refs, struct ref_transaction *transaction, struct strbuf *err); typedef int pack_refs_fn(struct ref_store *ref_store, unsigned int flags); -typedef int peel_ref_fn(struct ref_store *ref_store, - const char *refname, unsigned char *sha1); typedef int create_symref_fn(struct ref_store *ref_store, const char *ref_target, const char *refs_heads_master, const char *logmsg); -typedef int delete_refs_fn(struct ref_store *ref_store, +typedef int delete_refs_fn(struct ref_store *ref_store, const char *msg, struct string_list *refnames, unsigned int flags); typedef int rename_ref_fn(struct ref_store *ref_store, const char *oldref, const char *newref, const char *logmsg); +typedef int copy_ref_fn(struct ref_store *ref_store, + const char *oldref, const char *newref, + const char *logmsg); /* - * Iterate over the references in the specified ref_store that are - * within find_containing_dir(prefix). If prefix is NULL or the empty - * string, iterate over all references in the submodule. + * Iterate over the references in `ref_store` whose names start with + * `prefix`. `prefix` is matched as a literal string, without regard + * for path separators. If prefix is NULL or the empty string, iterate + * over all references in `ref_store`. The output is ordered by + * refname. */ typedef struct ref_iterator *ref_iterator_begin_fn( struct ref_store *ref_store, @@ -541,7 +571,7 @@ typedef int create_reflog_fn(struct ref_store *ref_store, const char *refname, int force_create, struct strbuf *err); typedef int delete_reflog_fn(struct ref_store *ref_store, const char *refname); typedef int reflog_expire_fn(struct ref_store *ref_store, - const char *refname, const unsigned char *sha1, + const char *refname, const struct object_id *oid, unsigned int flags, reflog_expiry_prepare_fn prepare_fn, reflog_expiry_should_prune_fn should_prune_fn, @@ -552,13 +582,13 @@ typedef int reflog_expire_fn(struct ref_store *ref_store, * Read a reference from the specified reference store, non-recursively. * Set type to describe the reference, and: * - * - If refname is the name of a normal reference, fill in sha1 + * - If refname is the name of a normal reference, fill in oid * (leaving referent unchanged). * * - If refname is the name of a symbolic reference, write the full * name of the reference to which it refers (e.g. * "refs/heads/master") to referent and set the REF_ISSYMREF bit in - * type (leaving sha1 unchanged). The caller is responsible for + * type (leaving oid unchanged). The caller is responsible for * validating that referent is a valid reference name. * * WARNING: refname might be used as part of a filename, so it is @@ -570,7 +600,7 @@ typedef int reflog_expire_fn(struct ref_store *ref_store, * * Return 0 on success. If the ref doesn't exist, set errno to ENOENT * and return -1. If the ref exists but is neither a symbolic ref nor - * a sha1, it is broken; set REF_ISBROKEN in type, set errno to + * an object ID, it is broken; set REF_ISBROKEN in type, set errno to * EINVAL, and return -1. If there is another error reading the ref, * set errno appropriately and return -1. * @@ -587,7 +617,7 @@ typedef int reflog_expire_fn(struct ref_store *ref_store, * refname will still be valid and unchanged. */ typedef int read_raw_ref_fn(struct ref_store *ref_store, - const char *refname, unsigned char *sha1, + const char *refname, struct object_id *oid, struct strbuf *referent, unsigned int *type); struct ref_storage_be { @@ -595,14 +625,17 @@ struct ref_storage_be { const char *name; ref_store_init_fn *init; ref_init_db_fn *init_db; - ref_transaction_commit_fn *transaction_commit; + + ref_transaction_prepare_fn *transaction_prepare; + ref_transaction_finish_fn *transaction_finish; + ref_transaction_abort_fn *transaction_abort; ref_transaction_commit_fn *initial_transaction_commit; pack_refs_fn *pack_refs; - peel_ref_fn *peel_ref; create_symref_fn *create_symref; delete_refs_fn *delete_refs; rename_ref_fn *rename_ref; + copy_ref_fn *copy_ref; ref_iterator_begin_fn *iterator_begin; read_raw_ref_fn *read_raw_ref; @@ -617,6 +650,7 @@ 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 |