diff options
Diffstat (limited to 'refs')
| -rw-r--r-- | refs/debug.c | 48 | ||||
| -rw-r--r-- | refs/files-backend.c | 636 | ||||
| -rw-r--r-- | refs/iterator.c | 75 | ||||
| -rw-r--r-- | refs/packed-backend.c | 143 | ||||
| -rw-r--r-- | refs/packed-backend.h | 6 | ||||
| -rw-r--r-- | refs/ref-cache.c | 9 | ||||
| -rw-r--r-- | refs/ref-cache.h | 2 | ||||
| -rw-r--r-- | refs/refs-internal.h | 143 | ||||
| -rw-r--r-- | refs/reftable-backend.c | 2333 |
9 files changed, 2928 insertions, 467 deletions
diff --git a/refs/debug.c b/refs/debug.c index b7ffc4ce67..547d9245b9 100644 --- a/refs/debug.c +++ b/refs/debug.c @@ -33,11 +33,18 @@ struct ref_store *maybe_debug_wrap_ref_store(const char *gitdir, struct ref_stor return (struct ref_store *)res; } -static int debug_init_db(struct ref_store *refs, struct strbuf *err) +static void debug_release(struct ref_store *refs) { struct debug_ref_store *drefs = (struct debug_ref_store *)refs; - int res = drefs->refs->be->init_db(drefs->refs, err); - trace_printf_key(&trace_refs, "init_db: %d\n", res); + drefs->refs->be->release(drefs->refs); + trace_printf_key(&trace_refs, "release\n"); +} + +static int debug_create_on_disk(struct ref_store *refs, int flags, struct strbuf *err) +{ + struct debug_ref_store *drefs = (struct debug_ref_store *)refs; + int res = drefs->refs->be->create_on_disk(drefs->refs, flags, err); + trace_printf_key(&trace_refs, "create_on_disk: %d\n", res); return res; } @@ -131,32 +138,6 @@ static int debug_pack_refs(struct ref_store *ref_store, struct pack_refs_opts *o return res; } -static int debug_create_symref(struct ref_store *ref_store, - const char *ref_name, const char *target, - const char *logmsg) -{ - struct debug_ref_store *drefs = (struct debug_ref_store *)ref_store; - int res = drefs->refs->be->create_symref(drefs->refs, ref_name, target, - logmsg); - trace_printf_key(&trace_refs, "create_symref: %s -> %s \"%s\": %d\n", ref_name, - target, logmsg, res); - return res; -} - -static int debug_delete_refs(struct ref_store *ref_store, const char *msg, - struct string_list *refnames, unsigned int flags) -{ - struct debug_ref_store *drefs = (struct debug_ref_store *)ref_store; - int res = - drefs->refs->be->delete_refs(drefs->refs, msg, refnames, flags); - int i; - trace_printf_key(&trace_refs, "delete_refs {\n"); - for (i = 0; i < refnames->nr; i++) - trace_printf_key(&trace_refs, "%s\n", refnames->items[i].string); - trace_printf_key(&trace_refs, "}: %d\n", res); - return res; -} - static int debug_rename_ref(struct ref_store *ref_store, const char *oldref, const char *newref, const char *logmsg) { @@ -195,7 +176,6 @@ static int debug_ref_iterator_advance(struct ref_iterator *ref_iterator) trace_printf_key(&trace_refs, "iterator_advance: %s (0)\n", diter->iter->refname); - diter->base.ordered = diter->iter->ordered; diter->base.refname = diter->iter->refname; diter->base.oid = diter->iter->oid; diter->base.flags = diter->iter->flags; @@ -236,7 +216,7 @@ debug_ref_iterator_begin(struct ref_store *ref_store, const char *prefix, drefs->refs->be->iterator_begin(drefs->refs, prefix, exclude_patterns, flags); struct debug_ref_iterator *diter = xcalloc(1, sizeof(*diter)); - base_ref_iterator_init(&diter->base, &debug_ref_iterator_vtable, 1); + base_ref_iterator_init(&diter->base, &debug_ref_iterator_vtable); diter->iter = res; trace_printf_key(&trace_refs, "ref_iterator_begin: \"%s\" (0x%x)\n", prefix, flags); @@ -440,10 +420,10 @@ static int debug_reflog_expire(struct ref_store *ref_store, const char *refname, } struct ref_storage_be refs_be_debug = { - .next = NULL, .name = "debug", .init = NULL, - .init_db = debug_init_db, + .release = debug_release, + .create_on_disk = debug_create_on_disk, /* * None of these should be NULL. If the "files" backend (in @@ -457,8 +437,6 @@ struct ref_storage_be refs_be_debug = { .initial_transaction_commit = debug_initial_transaction_commit, .pack_refs = debug_pack_refs, - .create_symref = debug_create_symref, - .delete_refs = debug_delete_refs, .rename_ref = debug_rename_ref, .copy_ref = debug_copy_ref, diff --git a/refs/files-backend.c b/refs/files-backend.c index 922e65e0d9..aa52d9be7c 100644 --- a/refs/files-backend.c +++ b/refs/files-backend.c @@ -1,3 +1,5 @@ +#define USE_THE_REPOSITORY_VARIABLE + #include "../git-compat-util.h" #include "../copy.h" #include "../environment.h" @@ -89,9 +91,9 @@ static void clear_loose_ref_cache(struct files_ref_store *refs) * Create a new submodule ref cache and add it to the internal * set of caches. */ -static struct ref_store *files_ref_store_create(struct repository *repo, - const char *gitdir, - unsigned int flags) +static struct ref_store *files_ref_store_init(struct repository *repo, + const char *gitdir, + unsigned int flags) { struct files_ref_store *refs = xcalloc(1, sizeof(*refs)); struct ref_store *ref_store = (struct ref_store *)refs; @@ -102,7 +104,7 @@ static struct ref_store *files_ref_store_create(struct repository *repo, get_common_dir_noenv(&sb, gitdir); refs->gitcommondir = strbuf_detach(&sb, NULL); refs->packed_ref_store = - packed_ref_store_create(repo, refs->gitcommondir, flags); + packed_ref_store_init(repo, refs->gitcommondir, flags); chdir_notify_reparent("files-backend $GIT_DIR", &refs->base.gitdir); chdir_notify_reparent("files-backend $GIT_COMMONDIR", @@ -149,6 +151,14 @@ static struct files_ref_store *files_downcast(struct ref_store *ref_store, return refs; } +static void files_ref_store_release(struct ref_store *ref_store) +{ + struct files_ref_store *refs = files_downcast(ref_store, 0, "release"); + free_ref_cache(refs->loose); + free(refs->gitcommondir); + ref_store_release(refs->packed_ref_store); +} + static void files_reflog_path(struct files_ref_store *refs, struct strbuf *sb, const char *refname) @@ -229,6 +239,38 @@ static void add_per_worktree_entries_to_dir(struct ref_dir *dir, const char *dir } } +static void loose_fill_ref_dir_regular_file(struct files_ref_store *refs, + const char *refname, + struct ref_dir *dir) +{ + struct object_id oid; + int flag; + + if (!refs_resolve_ref_unsafe(&refs->base, refname, RESOLVE_REF_READING, + &oid, &flag)) { + oidclr(&oid, the_repository->hash_algo); + flag |= REF_ISBROKEN; + } else if (is_null_oid(&oid)) { + /* + * It is so astronomically unlikely + * that null_oid is the OID of an + * actual object that we consider its + * appearance in a loose reference + * file to be repo corruption + * (probably due to a software bug). + */ + flag |= REF_ISBROKEN; + } + + if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) { + if (!refname_is_safe(refname)) + die("loose refname is dangerous: %s", refname); + oidclr(&oid, the_repository->hash_algo); + flag |= REF_BAD_NAME | REF_ISBROKEN; + } + add_entry_to_dir(dir, create_ref_entry(refname, &oid, flag)); +} + /* * Read the loose references from the namespace dirname into dir * (without recursing). dirname must end with '/'. dir must be the @@ -257,8 +299,6 @@ static void loose_fill_ref_dir(struct ref_store *ref_store, strbuf_add(&refname, dirname, dirnamelen); while ((de = readdir(d)) != NULL) { - struct object_id oid; - int flag; unsigned char dtype; if (de->d_name[0] == '.') @@ -274,33 +314,7 @@ static void loose_fill_ref_dir(struct ref_store *ref_store, create_dir_entry(dir->cache, refname.buf, refname.len)); } else if (dtype == DT_REG) { - if (!refs_resolve_ref_unsafe(&refs->base, - refname.buf, - RESOLVE_REF_READING, - &oid, &flag)) { - oidclr(&oid); - flag |= REF_ISBROKEN; - } else if (is_null_oid(&oid)) { - /* - * It is so astronomically unlikely - * that null_oid is the OID of an - * actual object that we consider its - * appearance in a loose reference - * file to be repo corruption - * (probably due to a software bug). - */ - flag |= REF_ISBROKEN; - } - - if (check_refname_format(refname.buf, - REFNAME_ALLOW_ONELEVEL)) { - if (!refname_is_safe(refname.buf)) - die("loose refname is dangerous: %s", refname.buf); - oidclr(&oid); - flag |= REF_BAD_NAME | REF_ISBROKEN; - } - add_entry_to_dir(dir, - create_ref_entry(refname.buf, &oid, flag)); + loose_fill_ref_dir_regular_file(refs, refname.buf, dir); } strbuf_setlen(&refname, dirnamelen); } @@ -311,9 +325,89 @@ static void loose_fill_ref_dir(struct ref_store *ref_store, add_per_worktree_entries_to_dir(dir, dirname); } -static struct ref_cache *get_loose_ref_cache(struct files_ref_store *refs) +static int for_each_root_ref(struct files_ref_store *refs, + int (*cb)(const char *refname, void *cb_data), + void *cb_data) +{ + struct strbuf path = STRBUF_INIT, refname = STRBUF_INIT; + const char *dirname = refs->loose->root->name; + struct dirent *de; + size_t dirnamelen; + int ret; + DIR *d; + + files_ref_path(refs, &path, dirname); + + d = opendir(path.buf); + if (!d) { + strbuf_release(&path); + return -1; + } + + strbuf_addstr(&refname, dirname); + dirnamelen = refname.len; + + while ((de = readdir(d)) != NULL) { + unsigned char dtype; + + if (de->d_name[0] == '.') + continue; + if (ends_with(de->d_name, ".lock")) + continue; + strbuf_addstr(&refname, de->d_name); + + dtype = get_dtype(de, &path, 1); + if (dtype == DT_REG && is_root_ref(de->d_name)) { + ret = cb(refname.buf, cb_data); + if (ret) + goto done; + } + + strbuf_setlen(&refname, dirnamelen); + } + + ret = 0; + +done: + strbuf_release(&refname); + strbuf_release(&path); + closedir(d); + return ret; +} + +struct fill_root_ref_data { + struct files_ref_store *refs; + struct ref_dir *dir; +}; + +static int fill_root_ref(const char *refname, void *cb_data) +{ + struct fill_root_ref_data *data = cb_data; + loose_fill_ref_dir_regular_file(data->refs, refname, data->dir); + return 0; +} + +/* + * Add root refs to the ref dir by parsing the directory for any files which + * follow the root ref syntax. + */ +static void add_root_refs(struct files_ref_store *refs, + struct ref_dir *dir) +{ + struct fill_root_ref_data data = { + .refs = refs, + .dir = dir, + }; + + for_each_root_ref(refs, fill_root_ref, &data); +} + +static struct ref_cache *get_loose_ref_cache(struct files_ref_store *refs, + unsigned int flags) { if (!refs->loose) { + struct ref_dir *dir; + /* * Mark the top-level directory complete because we * are about to read the only subdirectory that can @@ -324,12 +418,16 @@ static struct ref_cache *get_loose_ref_cache(struct files_ref_store *refs) /* We're going to fill the top level ourselves: */ refs->loose->root->flag &= ~REF_INCOMPLETE; + dir = get_ref_dir(refs->loose->root); + + if (flags & DO_FOR_EACH_INCLUDE_ROOT_REFS) + add_root_refs(refs, dir); + /* * Add an incomplete entry for "refs/" (to be filled * lazily): */ - add_entry_to_dir(get_ref_dir(refs->loose->root), - create_dir_entry(refs->loose, "refs/", 5)); + add_entry_to_dir(dir, create_dir_entry(refs->loose, "refs/", 5)); } return refs->loose; } @@ -735,8 +833,10 @@ retry: */ if (refs_verify_refname_available( refs->packed_ref_store, refname, - extras, NULL, err)) + extras, NULL, err)) { + ret = TRANSACTION_NAME_CONFLICT; goto error_return; + } } ret = 0; @@ -857,7 +957,7 @@ static struct ref_iterator *files_ref_iterator_begin( * disk, and re-reads it if not. */ - loose_iter = cache_ref_iterator_begin(get_loose_ref_cache(refs), + loose_iter = cache_ref_iterator_begin(get_loose_ref_cache(refs, flags), prefix, ref_store->repo, 1); /* @@ -879,8 +979,7 @@ static struct ref_iterator *files_ref_iterator_begin( CALLOC_ARRAY(iter, 1); ref_iterator = &iter->base; - base_ref_iterator_init(ref_iterator, &files_ref_iterator_vtable, - overlay_iter->ordered); + base_ref_iterator_init(ref_iterator, &files_ref_iterator_vtable); iter->iter0 = overlay_iter; iter->repo = ref_store->repo; iter->flags = flags; @@ -1053,7 +1152,7 @@ static struct ref_lock *lock_ref_oid_basic(struct files_ref_store *refs, if (!refs_resolve_ref_unsafe(&refs->base, lock->ref_name, 0, &lock->old_oid, NULL)) - oidclr(&lock->old_oid); + oidclr(&lock->old_oid, the_repository->hash_algo); goto out; error_return: @@ -1140,7 +1239,7 @@ static void prune_ref(struct files_ref_store *refs, struct ref_to_prune *r) ref_transaction_add_update( transaction, r->name, REF_NO_DEREF | REF_HAVE_NEW | REF_HAVE_OLD | REF_IS_PRUNING, - null_oid(), &r->oid, NULL); + null_oid(), &r->oid, NULL, NULL, NULL); if (ref_transaction_commit(transaction, &err)) goto cleanup; @@ -1171,7 +1270,8 @@ static void prune_refs(struct files_ref_store *refs, struct ref_to_prune **refs_ /* * Return true if the specified reference should be packed. */ -static int should_pack_ref(const char *refname, +static int should_pack_ref(struct files_ref_store *refs, + const char *refname, const struct object_id *oid, unsigned int ref_flags, struct pack_refs_opts *opts) { @@ -1187,7 +1287,7 @@ static int should_pack_ref(const char *refname, return 0; /* Do not pack broken refs: */ - if (!ref_resolves_to_object(refname, the_repository, oid, ref_flags)) + if (!ref_resolves_to_object(refname, refs->base.repo, oid, ref_flags)) return 0; if (ref_excluded(opts->exclusions, refname)) @@ -1218,15 +1318,15 @@ static int files_pack_refs(struct ref_store *ref_store, packed_refs_lock(refs->packed_ref_store, LOCK_DIE_ON_ERROR, &err); - iter = cache_ref_iterator_begin(get_loose_ref_cache(refs), NULL, - the_repository, 0); + iter = cache_ref_iterator_begin(get_loose_ref_cache(refs, 0), NULL, + refs->base.repo, 0); while ((ok = ref_iterator_advance(iter)) == ITER_OK) { /* * If the loose reference can be packed, add an entry * in the packed ref cache. If the reference should be * pruned, also add it to refs_to_prune. */ - if (!should_pack_ref(iter->refname, iter->oid, iter->flags, opts)) + if (!should_pack_ref(refs, iter->refname, iter->oid, iter->flags, opts)) continue; /* @@ -1234,7 +1334,7 @@ static int files_pack_refs(struct ref_store *ref_store, * packed-refs transaction: */ if (ref_transaction_update(transaction, iter->refname, - iter->oid, NULL, + iter->oid, NULL, NULL, NULL, REF_NO_DEREF, NULL, &err)) die("failure preparing to create packed reference %s: %s", iter->refname, err.buf); @@ -1263,54 +1363,6 @@ static int files_pack_refs(struct ref_store *ref_store, return 0; } -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 = - files_downcast(ref_store, REF_STORE_WRITE, "delete_refs"); - struct strbuf err = STRBUF_INIT; - int i, result = 0; - - if (!refnames->nr) - return 0; - - if (packed_refs_lock(refs->packed_ref_store, 0, &err)) - goto error; - - 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, msg, refname, NULL, flags)) - result |= error(_("could not remove reference %s"), refname); - } - - 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; -} - /* * People using contrib's git-new-workdir have .git/logs/refs -> * /some/other/path/.git/logs/refs, and that may live on another device. @@ -1371,7 +1423,8 @@ static int rename_tmp_log(struct files_ref_store *refs, const char *newrefname) return ret; } -static int write_ref_to_lockfile(struct ref_lock *lock, +static int write_ref_to_lockfile(struct files_ref_store *refs, + struct ref_lock *lock, const struct object_id *oid, int skip_oid_verification, struct strbuf *err); static int commit_ref_update(struct files_ref_store *refs, @@ -1519,7 +1572,7 @@ static int files_copy_or_rename_ref(struct ref_store *ref_store, } oidcpy(&lock->old_oid, &orig_oid); - if (write_ref_to_lockfile(lock, &orig_oid, 0, &err) || + if (write_ref_to_lockfile(refs, lock, &orig_oid, 0, &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); @@ -1539,7 +1592,7 @@ static int files_copy_or_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_oid, 0, &err) || + if (write_ref_to_lockfile(refs, lock, &orig_oid, 0, &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); @@ -1731,6 +1784,9 @@ static int files_log_ref_write(struct files_ref_store *refs, { int logfd, result; + if (flags & REF_SKIP_CREATE_REFLOG) + return 0; + if (log_all_ref_updates == LOG_REFS_UNSET) log_all_ref_updates = is_bare_repository() ? LOG_REFS_NONE : LOG_REFS_NORMAL; @@ -1773,7 +1829,8 @@ static int files_log_ref_write(struct files_ref_store *refs, * 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, +static int write_ref_to_lockfile(struct files_ref_store *refs, + struct ref_lock *lock, const struct object_id *oid, int skip_oid_verification, struct strbuf *err) { @@ -1782,7 +1839,7 @@ static int write_ref_to_lockfile(struct ref_lock *lock, int fd; if (!skip_oid_verification) { - o = parse_object(the_repository, oid); + o = parse_object(refs->base.repo, oid); if (!o) { strbuf_addf( err, @@ -1801,7 +1858,7 @@ static int write_ref_to_lockfile(struct ref_lock *lock, } } fd = get_lock_file_fd(&lock->lk); - if (write_in_full(fd, oid_to_hex(oid), the_hash_algo->hexsz) < 0 || + if (write_in_full(fd, oid_to_hex(oid), refs->base.repo->hash_algo->hexsz) < 0 || write_in_full(fd, &term, 1) < 0 || fsync_component(FSYNC_COMPONENT_REFERENCE, get_lock_file_fd(&lock->lk)) < 0 || close_ref_gently(lock) < 0) { @@ -1893,66 +1950,23 @@ static int create_ref_symlink(struct ref_lock *lock, const char *target) return ret; } -static void update_symref_reflog(struct files_ref_store *refs, - struct ref_lock *lock, const char *refname, - const char *target, const char *logmsg) +static int create_symref_lock(struct files_ref_store *refs, + struct ref_lock *lock, const char *refname, + const char *target, struct strbuf *err) { - struct strbuf err = STRBUF_INIT; - struct object_id new_oid; - - if (logmsg && - refs_resolve_ref_unsafe(&refs->base, target, - 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); - } -} - -static int create_symref_locked(struct files_ref_store *refs, - struct ref_lock *lock, const char *refname, - const char *target, const char *logmsg) -{ - if (prefer_symlink_refs && !create_ref_symlink(lock, target)) { - update_symref_reflog(refs, lock, refname, target, logmsg); - return 0; + if (!fdopen_lock_file(&lock->lk, "w")) { + strbuf_addf(err, "unable to fdopen %s: %s", + get_lock_file_path(&lock->lk), strerror(errno)); + return -1; } - if (!fdopen_lock_file(&lock->lk, "w")) - return error("unable to fdopen %s: %s", + if (fprintf(get_lock_file_fp(&lock->lk), "ref: %s\n", target) < 0) { + strbuf_addf(err, "unable to write to %s: %s", get_lock_file_path(&lock->lk), strerror(errno)); - - update_symref_reflog(refs, lock, refname, target, logmsg); - - /* no error check; commit_ref will check ferror */ - fprintf(get_lock_file_fp(&lock->lk), "ref: %s\n", target); - if (commit_ref(lock) < 0) - return error("unable to write symref for %s: %s", refname, - strerror(errno)); - return 0; -} - -static int files_create_symref(struct ref_store *ref_store, - const char *refname, const char *target, - const char *logmsg) -{ - struct files_ref_store *refs = - files_downcast(ref_store, REF_STORE_WRITE, "create_symref"); - struct strbuf err = STRBUF_INIT; - struct ref_lock *lock; - int ret; - - lock = lock_ref_oid_basic(refs, refname, &err); - if (!lock) { - error("%s", err.buf); - strbuf_release(&err); return -1; } - ret = create_symref_locked(refs, lock, refname, target, logmsg); - unlock_ref(lock); - return ret; + return 0; } static int files_reflog_exists(struct ref_store *ref_store, @@ -2164,10 +2178,8 @@ static int files_for_each_reflog_ent(struct ref_store *ref_store, struct files_reflog_iterator { struct ref_iterator base; - struct ref_store *ref_store; struct dir_iterator *dir_iterator; - struct object_id oid; }; static int files_reflog_iterator_advance(struct ref_iterator *ref_iterator) @@ -2178,25 +2190,13 @@ static int files_reflog_iterator_advance(struct ref_iterator *ref_iterator) int ok; while ((ok = dir_iterator_advance(diter)) == ITER_OK) { - int flags; - if (!S_ISREG(diter->st.st_mode)) continue; - if (diter->basename[0] == '.') - continue; - if (ends_with(diter->basename, ".lock")) + if (check_refname_format(diter->basename, + REFNAME_ALLOW_ONELEVEL)) continue; - if (!refs_resolve_ref_unsafe(iter->ref_store, - diter->relative_path, 0, - &iter->oid, &flags)) { - error("bad ref for %s", diter->path.buf); - continue; - } - iter->base.refname = diter->relative_path; - iter->base.oid = &iter->oid; - iter->base.flags = flags; return ITER_OK; } @@ -2241,7 +2241,7 @@ static struct ref_iterator *reflog_iterator_begin(struct ref_store *ref_store, strbuf_addf(&sb, "%s/logs", gitdir); - diter = dir_iterator_begin(sb.buf, 0); + diter = dir_iterator_begin(sb.buf, DIR_ITERATOR_SORTED); if (!diter) { strbuf_release(&sb); return empty_ref_iterator_begin(); @@ -2250,7 +2250,7 @@ static struct ref_iterator *reflog_iterator_begin(struct ref_store *ref_store, CALLOC_ARRAY(iter, 1); ref_iterator = &iter->base; - base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable, 0); + base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable); iter->dir_iterator = diter; iter->ref_store = ref_store; strbuf_release(&sb); @@ -2258,32 +2258,6 @@ static struct ref_iterator *reflog_iterator_begin(struct ref_store *ref_store, return ref_iterator; } -static enum iterator_selection reflog_iterator_select( - struct ref_iterator *iter_worktree, - struct ref_iterator *iter_common, - void *cb_data UNUSED) -{ - 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 (parse_worktree_ref(iter_common->refname, NULL, NULL, - NULL) == REF_WORKTREE_SHARED) - return ITER_SELECT_1; - - /* - * The main ref store may contain main worktree's - * per-worktree refs, which should be ignored - */ - return ITER_SKIP_1; - } else - return ITER_DONE; -} - static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_store) { struct files_ref_store *refs = @@ -2294,9 +2268,9 @@ static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_st return reflog_iterator_begin(ref_store, refs->gitcommondir); } else { return merge_ref_iterator_begin( - 0, reflog_iterator_begin(ref_store, refs->base.gitdir), + reflog_iterator_begin(ref_store, refs->base.gitdir), reflog_iterator_begin(ref_store, refs->gitcommondir), - reflog_iterator_select, refs); + ref_iterator_select, refs); } } @@ -2314,6 +2288,7 @@ static int split_head_update(struct ref_update *update, struct ref_update *new_update; if ((update->flags & REF_LOG_ONLY) || + (update->flags & REF_SKIP_CREATE_REFLOG) || (update->flags & REF_IS_PRUNING) || (update->flags & REF_UPDATE_VIA_HEAD)) return 0; @@ -2339,7 +2314,7 @@ static int split_head_update(struct ref_update *update, transaction, "HEAD", update->flags | REF_LOG_ONLY | REF_NO_DEREF, &update->new_oid, &update->old_oid, - update->msg); + NULL, NULL, update->msg); /* * Add "HEAD". This insertion is O(N) in the transaction @@ -2401,8 +2376,9 @@ static int split_symref_update(struct ref_update *update, new_update = ref_transaction_add_update( transaction, referent, new_flags, - &update->new_oid, &update->old_oid, - update->msg); + update->new_target ? NULL : &update->new_oid, + update->old_target ? NULL : &update->old_oid, + update->new_target, update->old_target, update->msg); new_update->parent_update = update; @@ -2431,17 +2407,6 @@ static int split_symref_update(struct ref_update *update, } /* - * Return the refname under which update was originally requested. - */ -static const char *original_update_refname(struct ref_update *update) -{ - while (update->parent_update) - update = update->parent_update; - - return update->refname; -} - -/* * Check whether the REF_HAVE_OLD and old_oid values stored in update * are consistent with oid, which is the reference's current value. If * everything is OK, return 0; otherwise, write an error message to @@ -2457,16 +2422,16 @@ static int check_old_oid(struct ref_update *update, struct object_id *oid, if (is_null_oid(&update->old_oid)) strbuf_addf(err, "cannot lock ref '%s': " "reference already exists", - original_update_refname(update)); + ref_update_original_update_refname(update)); else if (is_null_oid(oid)) strbuf_addf(err, "cannot lock ref '%s': " "reference is missing but expected %s", - original_update_refname(update), + ref_update_original_update_refname(update), oid_to_hex(&update->old_oid)); else strbuf_addf(err, "cannot lock ref '%s': " "is at %s but expected %s", - original_update_refname(update), + ref_update_original_update_refname(update), oid_to_hex(oid), oid_to_hex(&update->old_oid)); @@ -2494,14 +2459,13 @@ static int lock_ref_for_update(struct files_ref_store *refs, struct strbuf *err) { struct strbuf referent = STRBUF_INIT; - int mustexist = (update->flags & REF_HAVE_OLD) && - !is_null_oid(&update->old_oid); + int mustexist = ref_update_expects_existing_old_ref(update); int ret = 0; struct ref_lock *lock; files_assert_main_repository(refs, "lock_ref_for_update"); - if ((update->flags & REF_HAVE_NEW) && is_null_oid(&update->new_oid)) + if ((update->flags & REF_HAVE_NEW) && ref_update_has_null_new_value(update)) update->flags |= REF_DELETING; if (head_ref) { @@ -2520,7 +2484,7 @@ static int lock_ref_for_update(struct files_ref_store *refs, reason = strbuf_detach(err, NULL); strbuf_addf(err, "cannot lock ref '%s': %s", - original_update_refname(update), reason); + ref_update_original_update_refname(update), reason); free(reason); goto out; } @@ -2540,11 +2504,18 @@ static int lock_ref_for_update(struct files_ref_store *refs, if (update->flags & REF_HAVE_OLD) { strbuf_addf(err, "cannot lock ref '%s': " "error reading reference", - original_update_refname(update)); + ref_update_original_update_refname(update)); ret = TRANSACTION_GENERIC_ERROR; goto out; } - } else if (check_old_oid(update, &lock->old_oid, err)) { + } + + if (update->old_target) { + if (ref_update_check_old_target(referent.buf, update, err)) { + ret = TRANSACTION_GENERIC_ERROR; + goto out; + } + } else if (check_old_oid(update, &lock->old_oid, err)) { ret = TRANSACTION_GENERIC_ERROR; goto out; } @@ -2565,7 +2536,19 @@ static int lock_ref_for_update(struct files_ref_store *refs, } else { struct ref_update *parent_update; - if (check_old_oid(update, &lock->old_oid, err)) { + /* + * Even if the ref is a regular ref, if `old_target` is set, we + * fail with an error. + */ + if (update->old_target) { + strbuf_addf(err, _("cannot lock ref '%s': " + "expected symref with target '%s': " + "but is a regular ref"), + ref_update_original_update_refname(update), + update->old_target); + ret = TRANSACTION_GENERIC_ERROR; + goto out; + } else if (check_old_oid(update, &lock->old_oid, err)) { ret = TRANSACTION_GENERIC_ERROR; goto out; } @@ -2583,9 +2566,28 @@ static int lock_ref_for_update(struct files_ref_store *refs, } } - if ((update->flags & REF_HAVE_NEW) && - !(update->flags & REF_DELETING) && - !(update->flags & REF_LOG_ONLY)) { + if (update->new_target && !(update->flags & REF_LOG_ONLY)) { + if (create_symref_lock(refs, lock, update->refname, + update->new_target, err)) { + ret = TRANSACTION_GENERIC_ERROR; + goto out; + } + + if (close_ref_gently(lock)) { + strbuf_addf(err, "couldn't close '%s.lock'", + update->refname); + ret = TRANSACTION_GENERIC_ERROR; + goto out; + } + + /* + * Once we have created the symref lock, the commit + * phase of the transaction only needs to commit the lock. + */ + update->flags |= REF_NEEDS_COMMIT; + } else if ((update->flags & REF_HAVE_NEW) && + !(update->flags & REF_DELETING) && + !(update->flags & REF_LOG_ONLY)) { if (!(update->type & REF_ISSYMREF) && oideq(&lock->old_oid, &update->new_oid)) { /* @@ -2593,7 +2595,7 @@ static int lock_ref_for_update(struct files_ref_store *refs, * value, so we don't need to write it. */ } else if (write_ref_to_lockfile( - lock, &update->new_oid, + refs, lock, &update->new_oid, update->flags & REF_SKIP_OID_VERIFICATION, err)) { char *write_err = strbuf_detach(err, NULL); @@ -2793,7 +2795,7 @@ static int files_transaction_prepare(struct ref_store *ref_store, packed_transaction, update->refname, REF_HAVE_NEW | REF_NO_DEREF, &update->new_oid, NULL, - NULL); + NULL, NULL, NULL); } } @@ -2848,6 +2850,43 @@ cleanup: return ret; } +static int parse_and_write_reflog(struct files_ref_store *refs, + struct ref_update *update, + struct ref_lock *lock, + struct strbuf *err) +{ + if (update->new_target) { + /* + * We want to get the resolved OID for the target, to ensure + * that the correct value is added to the reflog. + */ + if (!refs_resolve_ref_unsafe(&refs->base, update->new_target, + RESOLVE_REF_READING, + &update->new_oid, NULL)) { + /* + * TODO: currently we skip creating reflogs for dangling + * symref updates. It would be nice to capture this as + * zero oid updates however. + */ + return 0; + } + } + + if (files_log_ref_write(refs, lock->ref_name, &lock->old_oid, + &update->new_oid, update->msg, update->flags, err)) { + char *old_msg = strbuf_detach(err, NULL); + + strbuf_addf(err, "cannot update the ref '%s': %s", + lock->ref_name, old_msg); + free(old_msg); + unlock_ref(lock); + update->backend_data = NULL; + return -1; + } + + return 0; +} + static int files_transaction_finish(struct ref_store *ref_store, struct ref_transaction *transaction, struct strbuf *err) @@ -2878,23 +2917,20 @@ static int files_transaction_finish(struct ref_store *ref_store, if (update->flags & REF_NEEDS_COMMIT || update->flags & REF_LOG_ONLY) { - if (files_log_ref_write(refs, - lock->ref_name, - &lock->old_oid, - &update->new_oid, - update->msg, update->flags, - err)) { - char *old_msg = strbuf_detach(err, NULL); - - strbuf_addf(err, "cannot update the ref '%s': %s", - lock->ref_name, old_msg); - free(old_msg); - unlock_ref(lock); - update->backend_data = NULL; + if (parse_and_write_reflog(refs, update, lock, err)) { ret = TRANSACTION_GENERIC_ERROR; goto cleanup; } } + + /* + * We try creating a symlink, if that succeeds we continue to the + * next update. If not, we try and create a regular symref. + */ + if (update->new_target && prefer_symlink_refs) + if (!create_ref_symlink(lock, update->new_target)) + continue; + if (update->flags & REF_NEEDS_COMMIT) { clear_loose_ref_cache(refs); if (commit_ref(lock)) { @@ -3078,7 +3114,7 @@ static int files_initial_transaction_commit(struct ref_store *ref_store, ref_transaction_add_update(packed_transaction, update->refname, update->flags & ~REF_HAVE_OLD, &update->new_oid, &update->old_oid, - NULL); + NULL, NULL, NULL); } if (packed_refs_lock(refs->packed_ref_store, 0, err)) { @@ -3242,7 +3278,7 @@ static int files_reflog_expire(struct ref_store *ref_store, rollback_lock_file(&reflog_lock); } else if (update && (write_in_full(get_lock_file_fd(&lock->lk), - oid_to_hex(&cb.last_kept_oid), the_hash_algo->hexsz) < 0 || + oid_to_hex(&cb.last_kept_oid), refs->base.repo->hash_algo->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", @@ -3266,39 +3302,125 @@ static int files_reflog_expire(struct ref_store *ref_store, return -1; } -static int files_init_db(struct ref_store *ref_store, struct strbuf *err UNUSED) +static int files_ref_store_create_on_disk(struct ref_store *ref_store, + int flags, + struct strbuf *err UNUSED) { struct files_ref_store *refs = - files_downcast(ref_store, REF_STORE_WRITE, "init_db"); + files_downcast(ref_store, REF_STORE_WRITE, "create"); struct strbuf sb = STRBUF_INIT; /* - * Create .git/refs/{heads,tags} + * We need to create a "refs" dir in any case so that older versions of + * Git can tell that this is a repository. This serves two main purposes: + * + * - Clients will know to stop walking the parent-directory chain when + * detecting the Git repository. Otherwise they may end up detecting + * a Git repository in a parent directory instead. + * + * - Instead of failing to detect a repository with unknown reference + * format altogether, old clients will print an error saying that + * they do not understand the reference format extension. */ - files_ref_path(refs, &sb, "refs/heads"); + strbuf_addf(&sb, "%s/refs", ref_store->gitdir); safe_create_dir(sb.buf, 1); + adjust_shared_perm(sb.buf); - strbuf_reset(&sb); - files_ref_path(refs, &sb, "refs/tags"); - safe_create_dir(sb.buf, 1); + /* + * There is no need to create directories for common refs when creating + * a worktree ref store. + */ + if (!(flags & REF_STORE_CREATE_ON_DISK_IS_WORKTREE)) { + /* + * Create .git/refs/{heads,tags} + */ + strbuf_reset(&sb); + files_ref_path(refs, &sb, "refs/heads"); + safe_create_dir(sb.buf, 1); + + strbuf_reset(&sb); + files_ref_path(refs, &sb, "refs/tags"); + safe_create_dir(sb.buf, 1); + } strbuf_release(&sb); return 0; } +struct remove_one_root_ref_data { + const char *gitdir; + struct strbuf *err; +}; + +static int remove_one_root_ref(const char *refname, + void *cb_data) +{ + struct remove_one_root_ref_data *data = cb_data; + struct strbuf buf = STRBUF_INIT; + int ret = 0; + + strbuf_addf(&buf, "%s/%s", data->gitdir, refname); + + ret = unlink(buf.buf); + if (ret < 0) + strbuf_addf(data->err, "could not delete %s: %s\n", + refname, strerror(errno)); + + strbuf_release(&buf); + return ret; +} + +static int files_ref_store_remove_on_disk(struct ref_store *ref_store, + struct strbuf *err) +{ + struct files_ref_store *refs = + files_downcast(ref_store, REF_STORE_WRITE, "remove"); + struct remove_one_root_ref_data data = { + .gitdir = refs->base.gitdir, + .err = err, + }; + struct strbuf sb = STRBUF_INIT; + int ret = 0; + + strbuf_addf(&sb, "%s/refs", refs->base.gitdir); + if (remove_dir_recursively(&sb, 0) < 0) { + strbuf_addf(err, "could not delete refs: %s", + strerror(errno)); + ret = -1; + } + strbuf_reset(&sb); + + strbuf_addf(&sb, "%s/logs", refs->base.gitdir); + if (remove_dir_recursively(&sb, 0) < 0) { + strbuf_addf(err, "could not delete logs: %s", + strerror(errno)); + ret = -1; + } + strbuf_reset(&sb); + + if (for_each_root_ref(refs, remove_one_root_ref, &data) < 0) + ret = -1; + + if (ref_store_remove_on_disk(refs->packed_ref_store, err) < 0) + ret = -1; + + strbuf_release(&sb); + return ret; +} + struct ref_storage_be refs_be_files = { - .next = NULL, .name = "files", - .init = files_ref_store_create, - .init_db = files_init_db, + .init = files_ref_store_init, + .release = files_ref_store_release, + .create_on_disk = files_ref_store_create_on_disk, + .remove_on_disk = files_ref_store_remove_on_disk, + .transaction_prepare = files_transaction_prepare, .transaction_finish = files_transaction_finish, .transaction_abort = files_transaction_abort, .initial_transaction_commit = files_initial_transaction_commit, .pack_refs = files_pack_refs, - .create_symref = files_create_symref, - .delete_refs = files_delete_refs, .rename_ref = files_rename_ref, .copy_ref = files_copy_ref, diff --git a/refs/iterator.c b/refs/iterator.c index 6b680f610e..d355ebf0d5 100644 --- a/refs/iterator.c +++ b/refs/iterator.c @@ -25,11 +25,9 @@ int ref_iterator_abort(struct ref_iterator *ref_iterator) } void base_ref_iterator_init(struct ref_iterator *iter, - struct ref_iterator_vtable *vtable, - int ordered) + struct ref_iterator_vtable *vtable) { iter->vtable = vtable; - iter->ordered = !!ordered; iter->refname = NULL; iter->oid = NULL; iter->flags = 0; @@ -74,7 +72,7 @@ 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, 1); + base_ref_iterator_init(ref_iterator, &empty_ref_iterator_vtable); return ref_iterator; } @@ -98,6 +96,49 @@ struct merge_ref_iterator { struct ref_iterator **current; }; +enum iterator_selection ref_iterator_select(struct ref_iterator *iter_worktree, + struct ref_iterator *iter_common, + void *cb_data UNUSED) +{ + if (iter_worktree && !iter_common) { + /* + * Return the worktree ref if there are no more common refs. + */ + return ITER_SELECT_0; + } else if (iter_common) { + /* + * In case we have pending worktree and common refs we need to + * yield them based on their lexicographical order. Worktree + * refs that have the same name as common refs shadow the + * latter. + */ + if (iter_worktree) { + int cmp = strcmp(iter_worktree->refname, + iter_common->refname); + if (cmp < 0) + return ITER_SELECT_0; + else if (!cmp) + return ITER_SELECT_0_SKIP_1; + } + + /* + * We now know that the lexicographically-next ref is a common + * ref. When the common ref is a shared one we return it. + */ + if (parse_worktree_ref(iter_common->refname, NULL, NULL, + NULL) == REF_WORKTREE_SHARED) + return ITER_SELECT_1; + + /* + * Otherwise, if the common ref is a per-worktree ref we skip + * it because it would belong to the main worktree, not ours. + */ + return ITER_SKIP_1; + } else { + return ITER_DONE; + } +} + static int merge_ref_iterator_advance(struct ref_iterator *ref_iterator) { struct merge_ref_iterator *iter = @@ -207,7 +248,6 @@ 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) { @@ -222,7 +262,7 @@ 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, ordered); + base_ref_iterator_init(ref_iterator, &merge_ref_iterator_vtable); iter->iter0 = iter0; iter->iter1 = iter1; iter->select = select; @@ -271,12 +311,9 @@ 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(1, front, back, - overlay_iterator_select, NULL); + return merge_ref_iterator_begin(front, back, overlay_iterator_select, NULL); } struct prefix_ref_iterator { @@ -315,16 +352,12 @@ static int prefix_ref_iterator_advance(struct ref_iterator *ref_iterator) if (cmp > 0) { /* - * If the source iterator is ordered, then we + * As the source iterator is ordered, 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; - } + ok = ref_iterator_abort(iter->iter0); + break; } if (iter->trim) { @@ -396,7 +429,7 @@ struct ref_iterator *prefix_ref_iterator_begin(struct ref_iterator *iter0, CALLOC_ARRAY(iter, 1); ref_iterator = &iter->base; - base_ref_iterator_init(ref_iterator, &prefix_ref_iterator_vtable, iter0->ordered); + base_ref_iterator_init(ref_iterator, &prefix_ref_iterator_vtable); iter->iter0 = iter0; iter->prefix = xstrdup(prefix); @@ -407,15 +440,15 @@ struct ref_iterator *prefix_ref_iterator_begin(struct ref_iterator *iter0, struct ref_iterator *current_ref_iter = NULL; -int do_for_each_repo_ref_iterator(struct repository *r, struct ref_iterator *iter, - each_repo_ref_fn fn, void *cb_data) +int do_for_each_ref_iterator(struct ref_iterator *iter, + each_ref_fn fn, void *cb_data) { int retval = 0, ok; struct ref_iterator *old_ref_iter = current_ref_iter; current_ref_iter = iter; while ((ok = ref_iterator_advance(iter)) == ITER_OK) { - retval = fn(r, iter->refname, iter->oid, iter->flags, cb_data); + retval = fn(iter->refname, iter->oid, iter->flags, cb_data); if (retval) { /* * If ref_iterator_abort() returns ITER_ERROR, diff --git a/refs/packed-backend.c b/refs/packed-backend.c index 5963e67c14..a0666407cd 100644 --- a/refs/packed-backend.c +++ b/refs/packed-backend.c @@ -1,5 +1,8 @@ +#define USE_THE_REPOSITORY_VARIABLE + #include "../git-compat-util.h" #include "../config.h" +#include "../dir.h" #include "../gettext.h" #include "../hash.h" #include "../hex.h" @@ -200,9 +203,14 @@ static int release_snapshot(struct snapshot *snapshot) } } -struct ref_store *packed_ref_store_create(struct repository *repo, - const char *gitdir, - unsigned int store_flags) +static size_t snapshot_hexsz(const struct snapshot *snapshot) +{ + return snapshot->refs->base.repo->hash_algo->hexsz; +} + +struct ref_store *packed_ref_store_init(struct repository *repo, + const char *gitdir, + unsigned int store_flags) { struct packed_ref_store *refs = xcalloc(1, sizeof(*refs)); struct ref_store *ref_store = (struct ref_store *)refs; @@ -252,6 +260,15 @@ static void clear_snapshot(struct packed_ref_store *refs) } } +static void packed_ref_store_release(struct ref_store *ref_store) +{ + struct packed_ref_store *refs = packed_downcast(ref_store, 0, "release"); + clear_snapshot(refs); + rollback_lock_file(&refs->lock); + delete_tempfile(&refs->tempfile); + free(refs->path); +} + static NORETURN void die_unterminated_line(const char *path, const char *p, size_t len) { @@ -280,11 +297,13 @@ struct snapshot_record { size_t len; }; -static int cmp_packed_ref_records(const void *v1, const void *v2) +static int cmp_packed_ref_records(const void *v1, const void *v2, + void *cb_data) { + const struct snapshot *snapshot = cb_data; const struct snapshot_record *e1 = v1, *e2 = v2; - const char *r1 = e1->start + the_hash_algo->hexsz + 1; - const char *r2 = e2->start + the_hash_algo->hexsz + 1; + const char *r1 = e1->start + snapshot_hexsz(snapshot) + 1; + const char *r2 = e2->start + snapshot_hexsz(snapshot) + 1; while (1) { if (*r1 == '\n') @@ -305,9 +324,9 @@ static int cmp_packed_ref_records(const void *v1, const void *v2) * refname. */ static int cmp_record_to_refname(const char *rec, const char *refname, - int start) + int start, const struct snapshot *snapshot) { - const char *r1 = rec + the_hash_algo->hexsz + 1; + const char *r1 = rec + snapshot_hexsz(snapshot) + 1; const char *r2 = refname; while (1) { @@ -354,7 +373,7 @@ static void sort_snapshot(struct snapshot *snapshot) if (!eol) /* The safety check should prevent this. */ BUG("unterminated line found in packed-refs"); - if (eol - pos < the_hash_algo->hexsz + 2) + if (eol - pos < snapshot_hexsz(snapshot) + 2) die_invalid_line(snapshot->refs->path, pos, eof - pos); eol++; @@ -380,7 +399,7 @@ static void sort_snapshot(struct snapshot *snapshot) if (sorted && nr > 1 && cmp_packed_ref_records(&records[nr - 2], - &records[nr - 1]) >= 0) + &records[nr - 1], snapshot) >= 0) sorted = 0; pos = eol; @@ -390,7 +409,7 @@ static void sort_snapshot(struct snapshot *snapshot) goto cleanup; /* We need to sort the memory. First we sort the records array: */ - QSORT(records, nr, cmp_packed_ref_records); + QSORT_S(records, nr, cmp_packed_ref_records, snapshot); /* * Allocate a new chunk of memory, and copy the old memory to @@ -466,7 +485,8 @@ static void verify_buffer_safe(struct snapshot *snapshot) return; last_line = find_start_of_record(start, eof - 1); - if (*(eof - 1) != '\n' || eof - last_line < the_hash_algo->hexsz + 2) + if (*(eof - 1) != '\n' || + eof - last_line < snapshot_hexsz(snapshot) + 2) die_invalid_line(snapshot->refs->path, last_line, eof - last_line); } @@ -561,7 +581,7 @@ static const char *find_reference_location_1(struct snapshot *snapshot, mid = lo + (hi - lo) / 2; rec = find_start_of_record(lo, mid); - cmp = cmp_record_to_refname(rec, refname, start); + cmp = cmp_record_to_refname(rec, refname, start, snapshot); if (cmp < 0) { lo = find_end_of_record(mid, hi); } else if (cmp > 0) { @@ -858,7 +878,7 @@ static int next_record(struct packed_ref_iterator *iter) iter->base.flags = REF_ISPACKED; p = iter->pos; - if (iter->eof - p < the_hash_algo->hexsz + 2 || + if (iter->eof - p < snapshot_hexsz(iter->snapshot) + 2 || parse_oid_hex(p, &iter->oid, &p) || !isspace(*p++)) die_invalid_line(iter->snapshot->refs->path, @@ -876,7 +896,7 @@ static int next_record(struct packed_ref_iterator *iter) if (!refname_is_safe(iter->base.refname)) die("packed refname is dangerous: %s", iter->base.refname); - oidclr(&iter->oid); + oidclr(&iter->oid, the_repository->hash_algo); iter->base.flags |= REF_BAD_NAME | REF_ISBROKEN; } if (iter->snapshot->peeled == PEELED_FULLY || @@ -888,7 +908,7 @@ static int next_record(struct packed_ref_iterator *iter) if (iter->pos < iter->eof && *iter->pos == '^') { p = iter->pos + 1; - if (iter->eof - p < the_hash_algo->hexsz + 1 || + if (iter->eof - p < snapshot_hexsz(iter->snapshot) + 1 || parse_oid_hex(p, &iter->peeled, &p) || *p++ != '\n') die_invalid_line(iter->snapshot->refs->path, @@ -901,13 +921,13 @@ static int next_record(struct packed_ref_iterator *iter) * we suppress it if the reference is broken: */ if ((iter->base.flags & REF_ISBROKEN)) { - oidclr(&iter->peeled); + oidclr(&iter->peeled, the_repository->hash_algo); iter->base.flags &= ~REF_KNOWS_PEELED; } else { iter->base.flags |= REF_KNOWS_PEELED; } } else { - oidclr(&iter->peeled); + oidclr(&iter->peeled, the_repository->hash_algo); } return ITER_OK; @@ -944,16 +964,13 @@ static int packed_ref_iterator_peel(struct ref_iterator *ref_iterator, struct packed_ref_iterator *iter = (struct packed_ref_iterator *)ref_iterator; - if (iter->repo != the_repository) - BUG("peeling for non-the_repository is not supported"); - 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) ? -1 : 0; + return peel_object(iter->repo, &iter->oid, peeled) ? -1 : 0; } } @@ -1111,7 +1128,7 @@ static struct ref_iterator *packed_ref_iterator_begin( CALLOC_ARRAY(iter, 1); ref_iterator = &iter->base; - base_ref_iterator_init(ref_iterator, &packed_ref_iterator_vtable, 1); + base_ref_iterator_init(ref_iterator, &packed_ref_iterator_vtable); if (exclude_patterns) populate_excluded_jump_list(iter, snapshot, exclude_patterns); @@ -1244,13 +1261,27 @@ int packed_refs_is_locked(struct ref_store *ref_store) static const char PACKED_REFS_HEADER[] = "# pack-refs with: peeled fully-peeled sorted \n"; -static int packed_init_db(struct ref_store *ref_store UNUSED, - struct strbuf *err UNUSED) +static int packed_ref_store_create_on_disk(struct ref_store *ref_store UNUSED, + int flags UNUSED, + struct strbuf *err UNUSED) { /* Nothing to do. */ return 0; } +static int packed_ref_store_remove_on_disk(struct ref_store *ref_store, + struct strbuf *err) +{ + struct packed_ref_store *refs = packed_downcast(ref_store, 0, "remove"); + + if (remove_path(refs->path) < 0) { + strbuf_addstr(err, "could not delete packed-refs"); + return -1; + } + + return 0; +} + /* * Write the packed refs from the current snapshot to the packed-refs * tempfile, incorporating any changes from `updates`. `updates` must @@ -1411,7 +1442,8 @@ static int write_with_updates(struct packed_ref_store *refs, i++; } else { struct object_id peeled; - int peel_error = peel_object(&update->new_oid, + int peel_error = peel_object(refs->base.repo, + &update->new_oid, &peeled); if (write_packed_entry(out, update->refname, @@ -1687,55 +1719,6 @@ static int packed_initial_transaction_commit(struct ref_store *ref_store UNUSED, 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 UNUSED, struct pack_refs_opts *pack_opts UNUSED) { @@ -1753,18 +1736,18 @@ static struct ref_iterator *packed_reflog_iterator_begin(struct ref_store *ref_s } struct ref_storage_be refs_be_packed = { - .next = NULL, .name = "packed", - .init = packed_ref_store_create, - .init_db = packed_init_db, + .init = packed_ref_store_init, + .release = packed_ref_store_release, + .create_on_disk = packed_ref_store_create_on_disk, + .remove_on_disk = packed_ref_store_remove_on_disk, + .transaction_prepare = packed_transaction_prepare, .transaction_finish = packed_transaction_finish, .transaction_abort = packed_transaction_abort, .initial_transaction_commit = packed_initial_transaction_commit, .pack_refs = packed_pack_refs, - .create_symref = NULL, - .delete_refs = packed_delete_refs, .rename_ref = NULL, .copy_ref = NULL, diff --git a/refs/packed-backend.h b/refs/packed-backend.h index 9dd8a344c3..09437ad13b 100644 --- a/refs/packed-backend.h +++ b/refs/packed-backend.h @@ -13,9 +13,9 @@ struct ref_transaction; * even among packed refs. */ -struct ref_store *packed_ref_store_create(struct repository *repo, - const char *gitdir, - unsigned int store_flags); +struct ref_store *packed_ref_store_init(struct repository *repo, + const char *gitdir, + unsigned int store_flags); /* * Lock the packed-refs file for writing. Flags is passed to diff --git a/refs/ref-cache.c b/refs/ref-cache.c index a372a00941..4ce519bbc8 100644 --- a/refs/ref-cache.c +++ b/refs/ref-cache.c @@ -71,6 +71,8 @@ static void free_ref_entry(struct ref_entry *entry) void free_ref_cache(struct ref_cache *cache) { + if (!cache) + return; free_ref_entry(cache->root); free(cache); } @@ -441,10 +443,7 @@ static int cache_ref_iterator_peel(struct ref_iterator *ref_iterator, { struct cache_ref_iterator *iter = (struct cache_ref_iterator *)ref_iterator; - - if (iter->repo != the_repository) - BUG("peeling for non-the_repository is not supported"); - return peel_object(ref_iterator->oid, peeled) ? -1 : 0; + return peel_object(iter->repo, ref_iterator->oid, peeled) ? -1 : 0; } static int cache_ref_iterator_abort(struct ref_iterator *ref_iterator) @@ -486,7 +485,7 @@ struct ref_iterator *cache_ref_iterator_begin(struct ref_cache *cache, CALLOC_ARRAY(iter, 1); ref_iterator = &iter->base; - base_ref_iterator_init(ref_iterator, &cache_ref_iterator_vtable, 1); + base_ref_iterator_init(ref_iterator, &cache_ref_iterator_vtable); ALLOC_GROW(iter->levels, 10, iter->levels_alloc); iter->levels_nr = 1; diff --git a/refs/ref-cache.h b/refs/ref-cache.h index 95c76e27c8..31ebe24f6c 100644 --- a/refs/ref-cache.h +++ b/refs/ref-cache.h @@ -1,7 +1,7 @@ #ifndef REFS_REF_CACHE_H #define REFS_REF_CACHE_H -#include "hash-ll.h" +#include "hash.h" struct ref_dir; struct ref_store; diff --git a/refs/refs-internal.h b/refs/refs-internal.h index 9db8aec4da..fa975d69aa 100644 --- a/refs/refs-internal.h +++ b/refs/refs-internal.h @@ -69,40 +69,6 @@ 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, - - /* - * object cannot be peeled because the named object (or an - * object referred to by a tag in the peel chain), does not - * exist. - */ - PEEL_INVALID = -1, - - /* object cannot be peeled because it is not a tag: */ - PEEL_NON_TAG = -2, - - /* ref_entry contains no peeled value because it is a symref: */ - PEEL_IS_SYMREF = -3, - - /* - * ref_entry cannot be peeled because it is broken (i.e., the - * symbolic reference cannot even be resolved to an object - * name): - */ - PEEL_BROKEN = -4 -}; - -/* - * 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 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 oid unchanged. - */ -enum peel_status peel_object(const struct object_id *name, struct object_id *oid); - /** * 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 @@ -125,6 +91,19 @@ struct ref_update { struct object_id old_oid; /* + * If set, point the reference to this value. This can also be + * used to convert regular references to become symbolic refs. + * Cannot be set together with `new_oid`. + */ + const char *new_target; + + /* + * If set, check that the reference previously pointed to this + * value. Cannot be set together with `old_oid`. + */ + const char *old_target; + + /* * One or more of REF_NO_DEREF, REF_FORCE_CREATE_REFLOG, * REF_HAVE_NEW, REF_HAVE_OLD, or backend-specific flags. */ @@ -173,6 +152,7 @@ struct ref_update *ref_transaction_add_update( const char *refname, unsigned int flags, const struct object_id *new_oid, const struct object_id *old_oid, + const char *new_target, const char *old_target, const char *msg); /* @@ -260,6 +240,12 @@ enum do_for_each_ref_flags { * INCLUDE_BROKEN, since they are otherwise not included at all. */ DO_FOR_EACH_OMIT_DANGLING_SYMREFS = (1 << 2), + + /* + * Include root refs i.e. HEAD and pseudorefs along with the regular + * refs. + */ + DO_FOR_EACH_INCLUDE_ROOT_REFS = (1 << 3), }; /* @@ -312,13 +298,6 @@ enum do_for_each_ref_flags { */ 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; @@ -387,14 +366,21 @@ typedef enum iterator_selection ref_iterator_select_fn( void *cb_data); /* + * An implementation of ref_iterator_select_fn that merges worktree and common + * refs. Per-worktree refs from the common iterator are ignored, worktree refs + * override common refs. Refs are selected lexicographically. + */ +enum iterator_selection ref_iterator_select(struct ref_iterator *iter_worktree, + struct ref_iterator *iter_common, + void *cb_data); + +/* * 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. A derived class should set `ordered` to 1 or 0 based on - * whether it generates its output in order by reference name. + * over. */ 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); @@ -423,8 +409,6 @@ 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, @@ -435,14 +419,11 @@ 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, - int ordered); + struct ref_iterator_vtable *vtable); /* * Base class destructor for ref_iterators. Destroy the ref_iterator @@ -502,9 +483,8 @@ extern struct ref_iterator *current_ref_iter; * adapter between the callback style of reference iteration and the * iterator style. */ -int do_for_each_repo_ref_iterator(struct repository *r, - struct ref_iterator *iter, - each_repo_ref_fn fn, void *cb_data); +int do_for_each_ref_iterator(struct ref_iterator *iter, + each_ref_fn fn, void *cb_data); struct ref_store; @@ -528,8 +508,20 @@ struct ref_store; typedef struct ref_store *ref_store_init_fn(struct repository *repo, const char *gitdir, unsigned int flags); +/* + * Release all memory and resources associated with the ref store. + */ +typedef void ref_store_release_fn(struct ref_store *refs); + +typedef int ref_store_create_on_disk_fn(struct ref_store *refs, + int flags, + struct strbuf *err); -typedef int ref_init_db_fn(struct ref_store *refs, struct strbuf *err); +/* + * Remove the reference store from disk. + */ +typedef int ref_store_remove_on_disk_fn(struct ref_store *refs, + struct strbuf *err); typedef int ref_transaction_prepare_fn(struct ref_store *refs, struct ref_transaction *transaction, @@ -549,12 +541,6 @@ typedef int ref_transaction_commit_fn(struct ref_store *refs, typedef int pack_refs_fn(struct ref_store *ref_store, struct pack_refs_opts *opts); -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, 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); @@ -665,10 +651,11 @@ typedef int read_symbolic_ref_fn(struct ref_store *ref_store, const char *refnam struct strbuf *referent); struct ref_storage_be { - struct ref_storage_be *next; const char *name; ref_store_init_fn *init; - ref_init_db_fn *init_db; + ref_store_release_fn *release; + ref_store_create_on_disk_fn *create_on_disk; + ref_store_remove_on_disk_fn *remove_on_disk; ref_transaction_prepare_fn *transaction_prepare; ref_transaction_finish_fn *transaction_finish; @@ -676,8 +663,6 @@ struct ref_storage_be { ref_transaction_commit_fn *initial_transaction_commit; pack_refs_fn *pack_refs; - create_symref_fn *create_symref; - delete_refs_fn *delete_refs; rename_ref_fn *rename_ref; copy_ref_fn *copy_ref; @@ -695,12 +680,13 @@ struct ref_storage_be { }; extern struct ref_storage_be refs_be_files; +extern struct ref_storage_be refs_be_reftable; extern struct ref_storage_be refs_be_packed; /* * A representation of the reference store for the main repository or * a submodule. The ref_store instances for submodules are kept in a - * hash map; see get_submodule_ref_store() for more info. + * hash map; see repo_get_submodule_ref_store() for more info. */ struct ref_store { /* The backend describing this ref_store's storage scheme: */ @@ -735,4 +721,31 @@ void base_ref_store_init(struct ref_store *refs, struct repository *repo, */ struct ref_store *maybe_debug_wrap_ref_store(const char *gitdir, struct ref_store *store); +/* + * Return the refname under which update was originally requested. + */ +const char *ref_update_original_update_refname(struct ref_update *update); + +/* + * Helper function to check if the new value is null, this + * takes into consideration that the update could be a regular + * ref or a symbolic ref. + */ +int ref_update_has_null_new_value(struct ref_update *update); + +/* + * Check whether the old_target values stored in update are consistent + * with the referent, which is the symbolic reference's current value. + * If everything is OK, return 0; otherwise, write an error message to + * err and return -1. + */ +int ref_update_check_old_target(const char *referent, struct ref_update *update, + struct strbuf *err); + +/* + * Check if the ref must exist, this means that the old_oid or + * old_target is non NULL. + */ +int ref_update_expects_existing_old_ref(struct ref_update *update); + #endif /* REFS_REFS_INTERNAL_H */ diff --git a/refs/reftable-backend.c b/refs/reftable-backend.c new file mode 100644 index 0000000000..fbe74c239d --- /dev/null +++ b/refs/reftable-backend.c @@ -0,0 +1,2333 @@ +#define USE_THE_REPOSITORY_VARIABLE + +#include "../git-compat-util.h" +#include "../abspath.h" +#include "../chdir-notify.h" +#include "../config.h" +#include "../dir.h" +#include "../environment.h" +#include "../gettext.h" +#include "../hash.h" +#include "../hex.h" +#include "../iterator.h" +#include "../ident.h" +#include "../lockfile.h" +#include "../object.h" +#include "../path.h" +#include "../refs.h" +#include "../reftable/reftable-stack.h" +#include "../reftable/reftable-record.h" +#include "../reftable/reftable-error.h" +#include "../reftable/reftable-iterator.h" +#include "../setup.h" +#include "../strmap.h" +#include "parse.h" +#include "refs-internal.h" + +/* + * 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) + +struct reftable_ref_store { + struct ref_store base; + + /* + * The main stack refers to the common dir and thus contains common + * refs as well as refs of the main repository. + */ + struct reftable_stack *main_stack; + /* + * The worktree stack refers to the gitdir in case the refdb is opened + * via a worktree. It thus contains the per-worktree refs. + */ + struct reftable_stack *worktree_stack; + /* + * Map of worktree stacks by their respective worktree names. The map + * is populated lazily when we try to resolve `worktrees/$worktree` refs. + */ + struct strmap worktree_stacks; + struct reftable_write_options write_options; + + unsigned int store_flags; + int err; +}; + +/* + * Downcast ref_store to reftable_ref_store. Die if ref_store is not a + * reftable_ref_store. required_flags is compared with ref_store's store_flags + * to ensure the ref_store has all required capabilities. "caller" is used in + * any necessary error messages. + */ +static struct reftable_ref_store *reftable_be_downcast(struct ref_store *ref_store, + unsigned int required_flags, + const char *caller) +{ + struct reftable_ref_store *refs; + + if (ref_store->be != &refs_be_reftable) + BUG("ref_store is type \"%s\" not \"reftables\" in %s", + ref_store->be->name, caller); + + refs = (struct reftable_ref_store *)ref_store; + + if ((refs->store_flags & required_flags) != required_flags) + BUG("operation %s requires abilities 0x%x, but only have 0x%x", + caller, required_flags, refs->store_flags); + + return refs; +} + +/* + * Some refs are global to the repository (refs/heads/{*}), while others are + * local to the worktree (eg. HEAD, refs/bisect/{*}). We solve this by having + * multiple separate databases (ie. multiple reftable/ directories), one for + * the shared refs, one for the current worktree refs, and one for each + * additional worktree. For reading, we merge the view of both the shared and + * the current worktree's refs, when necessary. + * + * This function also optionally assigns the rewritten reference name that is + * local to the stack. This translation is required when using worktree refs + * like `worktrees/$worktree/refs/heads/foo` as worktree stacks will store + * those references in their normalized form. + */ +static struct reftable_stack *stack_for(struct reftable_ref_store *store, + const char *refname, + const char **rewritten_ref) +{ + const char *wtname; + int wtname_len; + + if (!refname) + return store->main_stack; + + switch (parse_worktree_ref(refname, &wtname, &wtname_len, rewritten_ref)) { + case REF_WORKTREE_OTHER: { + static struct strbuf wtname_buf = STRBUF_INIT; + struct strbuf wt_dir = STRBUF_INIT; + struct reftable_stack *stack; + + /* + * We're using a static buffer here so that we don't need to + * allocate the worktree name whenever we look up a reference. + * This could be avoided if the strmap interface knew how to + * handle keys with a length. + */ + strbuf_reset(&wtname_buf); + strbuf_add(&wtname_buf, wtname, wtname_len); + + /* + * There is an edge case here: when the worktree references the + * current worktree, then we set up the stack once via + * `worktree_stacks` and once via `worktree_stack`. This is + * wasteful, but in the reading case it shouldn't matter. And + * in the writing case we would notice that the stack is locked + * already and error out when trying to write a reference via + * both stacks. + */ + stack = strmap_get(&store->worktree_stacks, wtname_buf.buf); + if (!stack) { + strbuf_addf(&wt_dir, "%s/worktrees/%s/reftable", + store->base.repo->commondir, wtname_buf.buf); + + store->err = reftable_new_stack(&stack, wt_dir.buf, + &store->write_options); + assert(store->err != REFTABLE_API_ERROR); + strmap_put(&store->worktree_stacks, wtname_buf.buf, stack); + } + + strbuf_release(&wt_dir); + return stack; + } + case REF_WORKTREE_CURRENT: + /* + * If there is no worktree stack then we're currently in the + * main worktree. We thus return the main stack in that case. + */ + if (!store->worktree_stack) + return store->main_stack; + return store->worktree_stack; + case REF_WORKTREE_MAIN: + case REF_WORKTREE_SHARED: + return store->main_stack; + default: + BUG("unhandled worktree reference type"); + } +} + +static int should_write_log(struct ref_store *refs, const char *refname) +{ + if (log_all_ref_updates == LOG_REFS_UNSET) + log_all_ref_updates = is_bare_repository() ? LOG_REFS_NONE : LOG_REFS_NORMAL; + + switch (log_all_ref_updates) { + case LOG_REFS_NONE: + return refs_reflog_exists(refs, refname); + case LOG_REFS_ALWAYS: + return 1; + case LOG_REFS_NORMAL: + if (should_autocreate_reflog(refname)) + return 1; + return refs_reflog_exists(refs, refname); + default: + BUG("unhandled core.logAllRefUpdates value %d", log_all_ref_updates); + } +} + +static void fill_reftable_log_record(struct reftable_log_record *log, const struct ident_split *split) +{ + const char *tz_begin; + int sign = 1; + + reftable_log_record_release(log); + log->value_type = REFTABLE_LOG_UPDATE; + log->value.update.name = + xstrndup(split->name_begin, split->name_end - split->name_begin); + log->value.update.email = + xstrndup(split->mail_begin, split->mail_end - split->mail_begin); + log->value.update.time = atol(split->date_begin); + + tz_begin = split->tz_begin; + if (*tz_begin == '-') { + sign = -1; + tz_begin++; + } + if (*tz_begin == '+') { + sign = 1; + tz_begin++; + } + + log->value.update.tz_offset = sign * atoi(tz_begin); +} + +static int read_ref_without_reload(struct reftable_stack *stack, + const char *refname, + struct object_id *oid, + struct strbuf *referent, + unsigned int *type) +{ + struct reftable_ref_record ref = {0}; + int ret; + + ret = reftable_stack_read_ref(stack, refname, &ref); + if (ret) + goto done; + + if (ref.value_type == REFTABLE_REF_SYMREF) { + strbuf_reset(referent); + strbuf_addstr(referent, ref.value.symref); + *type |= REF_ISSYMREF; + } else if (reftable_ref_record_val1(&ref)) { + oidread(oid, reftable_ref_record_val1(&ref), + the_repository->hash_algo); + } else { + /* We got a tombstone, which should not happen. */ + BUG("unhandled reference value type %d", ref.value_type); + } + +done: + assert(ret != REFTABLE_API_ERROR); + reftable_ref_record_release(&ref); + return ret; +} + +static int reftable_be_config(const char *var, const char *value, + const struct config_context *ctx, + void *_opts) +{ + struct reftable_write_options *opts = _opts; + + if (!strcmp(var, "reftable.blocksize")) { + unsigned long block_size = git_config_ulong(var, value, ctx->kvi); + if (block_size > 16777215) + die("reftable block size cannot exceed 16MB"); + opts->block_size = block_size; + } else if (!strcmp(var, "reftable.restartinterval")) { + unsigned long restart_interval = git_config_ulong(var, value, ctx->kvi); + if (restart_interval > UINT16_MAX) + die("reftable block size cannot exceed %u", (unsigned)UINT16_MAX); + opts->restart_interval = restart_interval; + } else if (!strcmp(var, "reftable.indexobjects")) { + opts->skip_index_objects = !git_config_bool(var, value); + } else if (!strcmp(var, "reftable.geometricfactor")) { + unsigned long factor = git_config_ulong(var, value, ctx->kvi); + if (factor > UINT8_MAX) + die("reftable geometric factor cannot exceed %u", (unsigned)UINT8_MAX); + opts->auto_compaction_factor = factor; + } + + return 0; +} + +static struct ref_store *reftable_be_init(struct repository *repo, + const char *gitdir, + unsigned int store_flags) +{ + struct reftable_ref_store *refs = xcalloc(1, sizeof(*refs)); + struct strbuf path = STRBUF_INIT; + int is_worktree; + mode_t mask; + + mask = umask(0); + umask(mask); + + base_ref_store_init(&refs->base, repo, gitdir, &refs_be_reftable); + strmap_init(&refs->worktree_stacks); + refs->store_flags = store_flags; + + refs->write_options.hash_id = repo->hash_algo->format_id; + refs->write_options.default_permissions = calc_shared_perm(0666 & ~mask); + refs->write_options.disable_auto_compact = + !git_env_bool("GIT_TEST_REFTABLE_AUTOCOMPACTION", 1); + + git_config(reftable_be_config, &refs->write_options); + + /* + * It is somewhat unfortunate that we have to mirror the default block + * size of the reftable library here. But given that the write options + * wouldn't be updated by the library here, and given that we require + * the proper block size to trim reflog message so that they fit, we + * must set up a proper value here. + */ + if (!refs->write_options.block_size) + refs->write_options.block_size = 4096; + + /* + * Set up the main reftable stack that is hosted in GIT_COMMON_DIR. + * This stack contains both the shared and the main worktree refs. + * + * Note that we don't try to resolve the path in case we have a + * worktree because `get_common_dir_noenv()` already does it for us. + */ + is_worktree = get_common_dir_noenv(&path, gitdir); + if (!is_worktree) { + strbuf_reset(&path); + strbuf_realpath(&path, gitdir, 0); + } + strbuf_addstr(&path, "/reftable"); + refs->err = reftable_new_stack(&refs->main_stack, path.buf, + &refs->write_options); + if (refs->err) + goto done; + + /* + * If we're in a worktree we also need to set up the worktree reftable + * stack that is contained in the per-worktree GIT_DIR. + * + * Ideally, we would also add the stack to our worktree stack map. But + * we have no way to figure out the worktree name here and thus can't + * do it efficiently. + */ + if (is_worktree) { + strbuf_reset(&path); + strbuf_addf(&path, "%s/reftable", gitdir); + + refs->err = reftable_new_stack(&refs->worktree_stack, path.buf, + &refs->write_options); + if (refs->err) + goto done; + } + + chdir_notify_reparent("reftables-backend $GIT_DIR", &refs->base.gitdir); + +done: + assert(refs->err != REFTABLE_API_ERROR); + strbuf_release(&path); + return &refs->base; +} + +static void reftable_be_release(struct ref_store *ref_store) +{ + struct reftable_ref_store *refs = reftable_be_downcast(ref_store, 0, "release"); + struct strmap_entry *entry; + struct hashmap_iter iter; + + if (refs->main_stack) { + reftable_stack_destroy(refs->main_stack); + refs->main_stack = NULL; + } + + if (refs->worktree_stack) { + reftable_stack_destroy(refs->worktree_stack); + refs->worktree_stack = NULL; + } + + strmap_for_each_entry(&refs->worktree_stacks, &iter, entry) + reftable_stack_destroy(entry->value); + strmap_clear(&refs->worktree_stacks, 0); +} + +static int reftable_be_create_on_disk(struct ref_store *ref_store, + int flags UNUSED, + struct strbuf *err UNUSED) +{ + struct reftable_ref_store *refs = + reftable_be_downcast(ref_store, REF_STORE_WRITE, "create"); + struct strbuf sb = STRBUF_INIT; + + strbuf_addf(&sb, "%s/reftable", refs->base.gitdir); + safe_create_dir(sb.buf, 1); + strbuf_reset(&sb); + + strbuf_addf(&sb, "%s/HEAD", refs->base.gitdir); + write_file(sb.buf, "ref: refs/heads/.invalid"); + adjust_shared_perm(sb.buf); + strbuf_reset(&sb); + + strbuf_addf(&sb, "%s/refs", refs->base.gitdir); + safe_create_dir(sb.buf, 1); + strbuf_reset(&sb); + + strbuf_addf(&sb, "%s/refs/heads", refs->base.gitdir); + write_file(sb.buf, "this repository uses the reftable format"); + adjust_shared_perm(sb.buf); + + strbuf_release(&sb); + return 0; +} + +static int reftable_be_remove_on_disk(struct ref_store *ref_store, + struct strbuf *err) +{ + struct reftable_ref_store *refs = + reftable_be_downcast(ref_store, REF_STORE_WRITE, "remove"); + struct strbuf sb = STRBUF_INIT; + int ret = 0; + + /* + * Release the ref store such that all stacks are closed. This is + * required so that the "tables.list" file is not open anymore, which + * would otherwise make it impossible to remove the file on Windows. + */ + reftable_be_release(ref_store); + + strbuf_addf(&sb, "%s/reftable", refs->base.gitdir); + if (remove_dir_recursively(&sb, 0) < 0) { + strbuf_addf(err, "could not delete reftables: %s", + strerror(errno)); + ret = -1; + } + strbuf_reset(&sb); + + strbuf_addf(&sb, "%s/HEAD", refs->base.gitdir); + if (unlink(sb.buf) < 0) { + strbuf_addf(err, "could not delete stub HEAD: %s", + strerror(errno)); + ret = -1; + } + strbuf_reset(&sb); + + strbuf_addf(&sb, "%s/refs/heads", refs->base.gitdir); + if (unlink(sb.buf) < 0) { + strbuf_addf(err, "could not delete stub heads: %s", + strerror(errno)); + ret = -1; + } + strbuf_reset(&sb); + + strbuf_addf(&sb, "%s/refs", refs->base.gitdir); + if (rmdir(sb.buf) < 0) { + strbuf_addf(err, "could not delete refs directory: %s", + strerror(errno)); + ret = -1; + } + + strbuf_release(&sb); + return ret; +} + +struct reftable_ref_iterator { + struct ref_iterator base; + struct reftable_ref_store *refs; + struct reftable_iterator iter; + struct reftable_ref_record ref; + struct object_id oid; + + const char *prefix; + size_t prefix_len; + unsigned int flags; + int err; +}; + +static int reftable_ref_iterator_advance(struct ref_iterator *ref_iterator) +{ + struct reftable_ref_iterator *iter = + (struct reftable_ref_iterator *)ref_iterator; + struct reftable_ref_store *refs = iter->refs; + + while (!iter->err) { + int flags = 0; + + iter->err = reftable_iterator_next_ref(&iter->iter, &iter->ref); + if (iter->err) + break; + + /* + * The files backend only lists references contained in "refs/" unless + * the root refs are to be included. We emulate the same behaviour here. + */ + if (!starts_with(iter->ref.refname, "refs/") && + !(iter->flags & DO_FOR_EACH_INCLUDE_ROOT_REFS && + is_root_ref(iter->ref.refname))) { + continue; + } + + if (iter->prefix_len && + strncmp(iter->prefix, iter->ref.refname, iter->prefix_len)) { + iter->err = 1; + break; + } + + if (iter->flags & DO_FOR_EACH_PER_WORKTREE_ONLY && + parse_worktree_ref(iter->ref.refname, NULL, NULL, NULL) != + REF_WORKTREE_CURRENT) + continue; + + switch (iter->ref.value_type) { + case REFTABLE_REF_VAL1: + oidread(&iter->oid, iter->ref.value.val1, + the_repository->hash_algo); + break; + case REFTABLE_REF_VAL2: + oidread(&iter->oid, iter->ref.value.val2.value, + the_repository->hash_algo); + break; + case REFTABLE_REF_SYMREF: + if (!refs_resolve_ref_unsafe(&iter->refs->base, iter->ref.refname, + RESOLVE_REF_READING, &iter->oid, &flags)) + oidclr(&iter->oid, the_repository->hash_algo); + break; + default: + BUG("unhandled reference value type %d", iter->ref.value_type); + } + + if (is_null_oid(&iter->oid)) + flags |= REF_ISBROKEN; + + if (check_refname_format(iter->ref.refname, REFNAME_ALLOW_ONELEVEL)) { + if (!refname_is_safe(iter->ref.refname)) + die(_("refname is dangerous: %s"), iter->ref.refname); + oidclr(&iter->oid, the_repository->hash_algo); + flags |= REF_BAD_NAME | REF_ISBROKEN; + } + + if (iter->flags & DO_FOR_EACH_OMIT_DANGLING_SYMREFS && + flags & REF_ISSYMREF && + flags & REF_ISBROKEN) + continue; + + if (!(iter->flags & DO_FOR_EACH_INCLUDE_BROKEN) && + !ref_resolves_to_object(iter->ref.refname, refs->base.repo, + &iter->oid, flags)) + continue; + + iter->base.refname = iter->ref.refname; + iter->base.oid = &iter->oid; + iter->base.flags = flags; + + break; + } + + if (iter->err > 0) { + if (ref_iterator_abort(ref_iterator) != ITER_DONE) + return ITER_ERROR; + return ITER_DONE; + } + + if (iter->err < 0) { + ref_iterator_abort(ref_iterator); + return ITER_ERROR; + } + + return ITER_OK; +} + +static int reftable_ref_iterator_peel(struct ref_iterator *ref_iterator, + struct object_id *peeled) +{ + struct reftable_ref_iterator *iter = + (struct reftable_ref_iterator *)ref_iterator; + + if (iter->ref.value_type == REFTABLE_REF_VAL2) { + oidread(peeled, iter->ref.value.val2.target_value, + the_repository->hash_algo); + return 0; + } + + return -1; +} + +static int reftable_ref_iterator_abort(struct ref_iterator *ref_iterator) +{ + struct reftable_ref_iterator *iter = + (struct reftable_ref_iterator *)ref_iterator; + reftable_ref_record_release(&iter->ref); + reftable_iterator_destroy(&iter->iter); + free(iter); + return ITER_DONE; +} + +static struct ref_iterator_vtable reftable_ref_iterator_vtable = { + .advance = reftable_ref_iterator_advance, + .peel = reftable_ref_iterator_peel, + .abort = reftable_ref_iterator_abort +}; + +static struct reftable_ref_iterator *ref_iterator_for_stack(struct reftable_ref_store *refs, + struct reftable_stack *stack, + const char *prefix, + int flags) +{ + struct reftable_ref_iterator *iter; + int ret; + + iter = xcalloc(1, sizeof(*iter)); + base_ref_iterator_init(&iter->base, &reftable_ref_iterator_vtable); + iter->prefix = prefix; + iter->prefix_len = prefix ? strlen(prefix) : 0; + iter->base.oid = &iter->oid; + iter->flags = flags; + iter->refs = refs; + + ret = refs->err; + if (ret) + goto done; + + ret = reftable_stack_reload(stack); + if (ret) + goto done; + + reftable_stack_init_ref_iterator(stack, &iter->iter); + ret = reftable_iterator_seek_ref(&iter->iter, prefix); + if (ret) + goto done; + +done: + iter->err = ret; + return iter; +} + +static struct ref_iterator *reftable_be_iterator_begin(struct ref_store *ref_store, + const char *prefix, + const char **exclude_patterns, + unsigned int flags) +{ + struct reftable_ref_iterator *main_iter, *worktree_iter; + struct reftable_ref_store *refs; + unsigned int required_flags = REF_STORE_READ; + + if (!(flags & DO_FOR_EACH_INCLUDE_BROKEN)) + required_flags |= REF_STORE_ODB; + refs = reftable_be_downcast(ref_store, required_flags, "ref_iterator_begin"); + + main_iter = ref_iterator_for_stack(refs, refs->main_stack, prefix, flags); + + /* + * The worktree stack is only set when we're in an actual worktree + * right now. If we aren't, then we return the common reftable + * iterator, only. + */ + if (!refs->worktree_stack) + return &main_iter->base; + + /* + * Otherwise we merge both the common and the per-worktree refs into a + * single iterator. + */ + worktree_iter = ref_iterator_for_stack(refs, refs->worktree_stack, prefix, flags); + return merge_ref_iterator_begin(&worktree_iter->base, &main_iter->base, + ref_iterator_select, NULL); +} + +static int reftable_be_read_raw_ref(struct ref_store *ref_store, + const char *refname, + struct object_id *oid, + struct strbuf *referent, + unsigned int *type, + int *failure_errno) +{ + struct reftable_ref_store *refs = + reftable_be_downcast(ref_store, REF_STORE_READ, "read_raw_ref"); + struct reftable_stack *stack = stack_for(refs, refname, &refname); + int ret; + + if (refs->err < 0) + return refs->err; + + ret = reftable_stack_reload(stack); + if (ret) + return ret; + + ret = read_ref_without_reload(stack, refname, oid, referent, type); + if (ret < 0) + return ret; + if (ret > 0) { + *failure_errno = ENOENT; + return -1; + } + + return 0; +} + +static int reftable_be_read_symbolic_ref(struct ref_store *ref_store, + const char *refname, + struct strbuf *referent) +{ + struct reftable_ref_store *refs = + reftable_be_downcast(ref_store, REF_STORE_READ, "read_symbolic_ref"); + struct reftable_stack *stack = stack_for(refs, refname, &refname); + struct reftable_ref_record ref = {0}; + int ret; + + ret = reftable_stack_reload(stack); + if (ret) + return ret; + + ret = reftable_stack_read_ref(stack, refname, &ref); + if (ret == 0 && ref.value_type == REFTABLE_REF_SYMREF) + strbuf_addstr(referent, ref.value.symref); + else + ret = -1; + + reftable_ref_record_release(&ref); + return ret; +} + +struct reftable_transaction_update { + struct ref_update *update; + struct object_id current_oid; +}; + +struct write_transaction_table_arg { + struct reftable_ref_store *refs; + struct reftable_stack *stack; + struct reftable_addition *addition; + struct reftable_transaction_update *updates; + size_t updates_nr; + size_t updates_alloc; + size_t updates_expected; +}; + +struct reftable_transaction_data { + struct write_transaction_table_arg *args; + size_t args_nr, args_alloc; +}; + +static void free_transaction_data(struct reftable_transaction_data *tx_data) +{ + if (!tx_data) + return; + for (size_t i = 0; i < tx_data->args_nr; i++) { + reftable_addition_destroy(tx_data->args[i].addition); + free(tx_data->args[i].updates); + } + free(tx_data->args); + free(tx_data); +} + +/* + * Prepare transaction update for the given reference update. This will cause + * us to lock the corresponding reftable stack for concurrent modification. + */ +static int prepare_transaction_update(struct write_transaction_table_arg **out, + struct reftable_ref_store *refs, + struct reftable_transaction_data *tx_data, + struct ref_update *update, + struct strbuf *err) +{ + struct reftable_stack *stack = stack_for(refs, update->refname, NULL); + struct write_transaction_table_arg *arg = NULL; + size_t i; + int ret; + + /* + * Search for a preexisting stack update. If there is one then we add + * the update to it, otherwise we set up a new stack update. + */ + for (i = 0; !arg && i < tx_data->args_nr; i++) + if (tx_data->args[i].stack == stack) + arg = &tx_data->args[i]; + + if (!arg) { + struct reftable_addition *addition; + + ret = reftable_stack_reload(stack); + if (ret) + return ret; + + ret = reftable_stack_new_addition(&addition, stack); + if (ret) { + if (ret == REFTABLE_LOCK_ERROR) + strbuf_addstr(err, "cannot lock references"); + return ret; + } + + ALLOC_GROW(tx_data->args, tx_data->args_nr + 1, + tx_data->args_alloc); + arg = &tx_data->args[tx_data->args_nr++]; + arg->refs = refs; + arg->stack = stack; + arg->addition = addition; + arg->updates = NULL; + arg->updates_nr = 0; + arg->updates_alloc = 0; + arg->updates_expected = 0; + } + + arg->updates_expected++; + + if (out) + *out = arg; + + return 0; +} + +/* + * Queue a reference update for the correct stack. We potentially need to + * handle multiple stack updates in a single transaction when it spans across + * multiple worktrees. + */ +static int queue_transaction_update(struct reftable_ref_store *refs, + struct reftable_transaction_data *tx_data, + struct ref_update *update, + struct object_id *current_oid, + struct strbuf *err) +{ + struct write_transaction_table_arg *arg = NULL; + int ret; + + if (update->backend_data) + BUG("reference update queued more than once"); + + ret = prepare_transaction_update(&arg, refs, tx_data, update, err); + if (ret < 0) + return ret; + + ALLOC_GROW(arg->updates, arg->updates_nr + 1, + arg->updates_alloc); + arg->updates[arg->updates_nr].update = update; + oidcpy(&arg->updates[arg->updates_nr].current_oid, current_oid); + update->backend_data = &arg->updates[arg->updates_nr++]; + + return 0; +} + +static int reftable_be_transaction_prepare(struct ref_store *ref_store, + struct ref_transaction *transaction, + struct strbuf *err) +{ + struct reftable_ref_store *refs = + reftable_be_downcast(ref_store, REF_STORE_WRITE|REF_STORE_MAIN, "ref_transaction_prepare"); + struct strbuf referent = STRBUF_INIT, head_referent = STRBUF_INIT; + struct string_list affected_refnames = STRING_LIST_INIT_NODUP; + struct reftable_transaction_data *tx_data = NULL; + struct object_id head_oid; + unsigned int head_type = 0; + size_t i; + int ret; + + ret = refs->err; + if (ret < 0) + goto done; + + tx_data = xcalloc(1, sizeof(*tx_data)); + + /* + * Preprocess all updates. For one we check that there are no duplicate + * reference updates in this transaction. Second, we lock all stacks + * that will be modified during the transaction. + */ + for (i = 0; i < transaction->nr; i++) { + ret = prepare_transaction_update(NULL, refs, tx_data, + transaction->updates[i], err); + if (ret) + goto done; + + string_list_append(&affected_refnames, + transaction->updates[i]->refname); + } + + /* + * Now that we have counted updates per stack we can preallocate their + * arrays. This avoids having to reallocate many times. + */ + for (i = 0; i < tx_data->args_nr; i++) { + CALLOC_ARRAY(tx_data->args[i].updates, tx_data->args[i].updates_expected); + tx_data->args[i].updates_alloc = tx_data->args[i].updates_expected; + } + + /* + * Fail if a refname appears more than once in the transaction. + * This code is taken from the files backend and is a good candidate to + * be moved into the generic layer. + */ + string_list_sort(&affected_refnames); + if (ref_update_reject_duplicates(&affected_refnames, err)) { + ret = TRANSACTION_GENERIC_ERROR; + goto done; + } + + ret = read_ref_without_reload(stack_for(refs, "HEAD", NULL), "HEAD", &head_oid, + &head_referent, &head_type); + if (ret < 0) + goto done; + ret = 0; + + for (i = 0; i < transaction->nr; i++) { + struct ref_update *u = transaction->updates[i]; + struct object_id current_oid = {0}; + struct reftable_stack *stack; + const char *rewritten_ref; + + stack = stack_for(refs, u->refname, &rewritten_ref); + + /* Verify that the new object ID is valid. */ + if ((u->flags & REF_HAVE_NEW) && !is_null_oid(&u->new_oid) && + !(u->flags & REF_SKIP_OID_VERIFICATION) && + !(u->flags & REF_LOG_ONLY)) { + struct object *o = parse_object(refs->base.repo, &u->new_oid); + if (!o) { + strbuf_addf(err, + _("trying to write ref '%s' with nonexistent object %s"), + u->refname, oid_to_hex(&u->new_oid)); + ret = -1; + goto done; + } + + if (o->type != OBJ_COMMIT && is_branch(u->refname)) { + strbuf_addf(err, _("trying to write non-commit object %s to branch '%s'"), + oid_to_hex(&u->new_oid), u->refname); + ret = -1; + goto done; + } + } + + /* + * When we update the reference that HEAD points to we enqueue + * a second log-only update for HEAD so that its reflog is + * updated accordingly. + */ + if (head_type == REF_ISSYMREF && + !(u->flags & REF_LOG_ONLY) && + !(u->flags & REF_UPDATE_VIA_HEAD) && + !strcmp(rewritten_ref, head_referent.buf)) { + struct ref_update *new_update; + + /* + * First make sure that HEAD is not already in the + * transaction. This check is O(lg N) in the transaction + * size, but it happens at most once per transaction. + */ + if (string_list_has_string(&affected_refnames, "HEAD")) { + /* An entry already existed */ + strbuf_addf(err, + _("multiple updates for 'HEAD' (including one " + "via its referent '%s') are not allowed"), + u->refname); + ret = TRANSACTION_NAME_CONFLICT; + goto done; + } + + new_update = ref_transaction_add_update( + transaction, "HEAD", + u->flags | REF_LOG_ONLY | REF_NO_DEREF, + &u->new_oid, &u->old_oid, NULL, NULL, u->msg); + string_list_insert(&affected_refnames, new_update->refname); + } + + ret = read_ref_without_reload(stack, rewritten_ref, + ¤t_oid, &referent, &u->type); + if (ret < 0) + goto done; + if (ret > 0 && !ref_update_expects_existing_old_ref(u)) { + /* + * The reference does not exist, and we either have no + * old object ID or expect the reference to not exist. + * We can thus skip below safety checks as well as the + * symref splitting. But we do want to verify that + * there is no conflicting reference here so that we + * can output a proper error message instead of failing + * at a later point. + */ + ret = refs_verify_refname_available(ref_store, u->refname, + &affected_refnames, NULL, err); + if (ret < 0) + goto done; + + /* + * There is no need to write the reference deletion + * when the reference in question doesn't exist. + */ + if ((u->flags & REF_HAVE_NEW) && !ref_update_has_null_new_value(u)) { + ret = queue_transaction_update(refs, tx_data, u, + ¤t_oid, err); + if (ret) + goto done; + } + + continue; + } + if (ret > 0) { + /* The reference does not exist, but we expected it to. */ + strbuf_addf(err, _("cannot lock ref '%s': " + "unable to resolve reference '%s'"), + ref_update_original_update_refname(u), u->refname); + ret = -1; + goto done; + } + + if (u->type & REF_ISSYMREF) { + /* + * The reftable stack is locked at this point already, + * so it is safe to call `refs_resolve_ref_unsafe()` + * here without causing races. + */ + const char *resolved = refs_resolve_ref_unsafe(&refs->base, u->refname, 0, + ¤t_oid, NULL); + + if (u->flags & REF_NO_DEREF) { + if (u->flags & REF_HAVE_OLD && !resolved) { + strbuf_addf(err, _("cannot lock ref '%s': " + "error reading reference"), u->refname); + ret = -1; + goto done; + } + } else { + struct ref_update *new_update; + int new_flags; + + new_flags = u->flags; + if (!strcmp(rewritten_ref, "HEAD")) + new_flags |= REF_UPDATE_VIA_HEAD; + + /* + * If we are updating a symref (eg. HEAD), we should also + * update the branch that the symref points to. + * + * This is generic functionality, and would be better + * done in refs.c, but the current implementation is + * intertwined with the locking in files-backend.c. + */ + new_update = ref_transaction_add_update( + transaction, referent.buf, new_flags, + u->new_target ? NULL : &u->new_oid, + u->old_target ? NULL : &u->old_oid, + u->new_target, u->old_target, u->msg); + + new_update->parent_update = u; + + /* + * Change the symbolic ref update to log only. Also, it + * doesn't need to check its old OID value, as that will be + * done when new_update is processed. + */ + u->flags |= REF_LOG_ONLY | REF_NO_DEREF; + u->flags &= ~REF_HAVE_OLD; + + if (string_list_has_string(&affected_refnames, new_update->refname)) { + strbuf_addf(err, + _("multiple updates for '%s' (including one " + "via symref '%s') are not allowed"), + referent.buf, u->refname); + ret = TRANSACTION_NAME_CONFLICT; + goto done; + } + string_list_insert(&affected_refnames, new_update->refname); + } + } + + /* + * Verify that the old object matches our expectations. Note + * that the error messages here do not make a lot of sense in + * the context of the reftable backend as we never lock + * individual refs. But the error messages match what the files + * backend returns, which keeps our tests happy. + */ + if (u->old_target) { + if (!(u->type & REF_ISSYMREF)) { + strbuf_addf(err, _("cannot lock ref '%s': " + "expected symref with target '%s': " + "but is a regular ref"), + ref_update_original_update_refname(u), + u->old_target); + ret = -1; + goto done; + } + + if (ref_update_check_old_target(referent.buf, u, err)) { + ret = -1; + goto done; + } + } else if ((u->flags & REF_HAVE_OLD) && !oideq(¤t_oid, &u->old_oid)) { + if (is_null_oid(&u->old_oid)) + strbuf_addf(err, _("cannot lock ref '%s': " + "reference already exists"), + ref_update_original_update_refname(u)); + else if (is_null_oid(¤t_oid)) + strbuf_addf(err, _("cannot lock ref '%s': " + "reference is missing but expected %s"), + ref_update_original_update_refname(u), + oid_to_hex(&u->old_oid)); + else + strbuf_addf(err, _("cannot lock ref '%s': " + "is at %s but expected %s"), + ref_update_original_update_refname(u), + oid_to_hex(¤t_oid), + oid_to_hex(&u->old_oid)); + ret = -1; + goto done; + } + + /* + * If all of the following conditions are true: + * + * - We're not about to write a symref. + * - We're not about to write a log-only entry. + * - Old and new object ID are different. + * + * Then we're essentially doing a no-op update that can be + * skipped. This is not only for the sake of efficiency, but + * also skips writing unneeded reflog entries. + */ + if ((u->type & REF_ISSYMREF) || + (u->flags & REF_LOG_ONLY) || + (u->flags & REF_HAVE_NEW && !oideq(¤t_oid, &u->new_oid))) { + ret = queue_transaction_update(refs, tx_data, u, + ¤t_oid, err); + if (ret) + goto done; + } + } + + transaction->backend_data = tx_data; + transaction->state = REF_TRANSACTION_PREPARED; + +done: + assert(ret != REFTABLE_API_ERROR); + if (ret < 0) { + free_transaction_data(tx_data); + transaction->state = REF_TRANSACTION_CLOSED; + if (!err->len) + strbuf_addf(err, _("reftable: transaction prepare: %s"), + reftable_error_str(ret)); + } + string_list_clear(&affected_refnames, 0); + strbuf_release(&referent); + strbuf_release(&head_referent); + + return ret; +} + +static int reftable_be_transaction_abort(struct ref_store *ref_store, + struct ref_transaction *transaction, + struct strbuf *err) +{ + struct reftable_transaction_data *tx_data = transaction->backend_data; + free_transaction_data(tx_data); + transaction->state = REF_TRANSACTION_CLOSED; + return 0; +} + +static int transaction_update_cmp(const void *a, const void *b) +{ + return strcmp(((struct reftable_transaction_update *)a)->update->refname, + ((struct reftable_transaction_update *)b)->update->refname); +} + +static int write_transaction_table(struct reftable_writer *writer, void *cb_data) +{ + struct write_transaction_table_arg *arg = cb_data; + uint64_t ts = reftable_stack_next_update_index(arg->stack); + struct reftable_log_record *logs = NULL; + struct ident_split committer_ident = {0}; + size_t logs_nr = 0, logs_alloc = 0, i; + const char *committer_info; + int ret = 0; + + committer_info = git_committer_info(0); + if (split_ident_line(&committer_ident, committer_info, strlen(committer_info))) + BUG("failed splitting committer info"); + + QSORT(arg->updates, arg->updates_nr, transaction_update_cmp); + + reftable_writer_set_limits(writer, ts, ts); + + for (i = 0; i < arg->updates_nr; i++) { + struct reftable_transaction_update *tx_update = &arg->updates[i]; + struct ref_update *u = tx_update->update; + + /* + * Write a reflog entry when updating a ref to point to + * something new in either of the following cases: + * + * - The reference is about to be deleted. We always want to + * delete the reflog in that case. + * - REF_FORCE_CREATE_REFLOG is set, asking us to always create + * the reflog entry. + * - `core.logAllRefUpdates` tells us to create the reflog for + * the given ref. + */ + if ((u->flags & REF_HAVE_NEW) && + !(u->type & REF_ISSYMREF) && + ref_update_has_null_new_value(u)) { + struct reftable_log_record log = {0}; + struct reftable_iterator it = {0}; + + reftable_stack_init_log_iterator(arg->stack, &it); + + /* + * When deleting refs we also delete all reflog entries + * with them. While it is not strictly required to + * delete reflogs together with their refs, this + * matches the behaviour of the files backend. + * + * Unfortunately, we have no better way than to delete + * all reflog entries one by one. + */ + ret = reftable_iterator_seek_log(&it, u->refname); + while (ret == 0) { + struct reftable_log_record *tombstone; + + ret = reftable_iterator_next_log(&it, &log); + if (ret < 0) + break; + if (ret > 0 || strcmp(log.refname, u->refname)) { + ret = 0; + break; + } + + ALLOC_GROW(logs, logs_nr + 1, logs_alloc); + tombstone = &logs[logs_nr++]; + tombstone->refname = xstrdup(u->refname); + tombstone->value_type = REFTABLE_LOG_DELETION; + tombstone->update_index = log.update_index; + } + + reftable_log_record_release(&log); + reftable_iterator_destroy(&it); + + if (ret) + goto done; + } else if (!(u->flags & REF_SKIP_CREATE_REFLOG) && + (u->flags & REF_HAVE_NEW) && + (u->flags & REF_FORCE_CREATE_REFLOG || + should_write_log(&arg->refs->base, u->refname))) { + struct reftable_log_record *log; + int create_reflog = 1; + + if (u->new_target) { + if (!refs_resolve_ref_unsafe(&arg->refs->base, u->new_target, + RESOLVE_REF_READING, &u->new_oid, NULL)) { + /* + * TODO: currently we skip creating reflogs for dangling + * symref updates. It would be nice to capture this as + * zero oid updates however. + */ + create_reflog = 0; + } + } + + if (create_reflog) { + ALLOC_GROW(logs, logs_nr + 1, logs_alloc); + log = &logs[logs_nr++]; + memset(log, 0, sizeof(*log)); + + fill_reftable_log_record(log, &committer_ident); + log->update_index = ts; + log->refname = xstrdup(u->refname); + memcpy(log->value.update.new_hash, + u->new_oid.hash, GIT_MAX_RAWSZ); + memcpy(log->value.update.old_hash, + tx_update->current_oid.hash, GIT_MAX_RAWSZ); + log->value.update.message = + xstrndup(u->msg, arg->refs->write_options.block_size / 2); + } + } + + if (u->flags & REF_LOG_ONLY) + continue; + + if (u->new_target) { + struct reftable_ref_record ref = { + .refname = (char *)u->refname, + .value_type = REFTABLE_REF_SYMREF, + .value.symref = (char *)u->new_target, + .update_index = ts, + }; + + ret = reftable_writer_add_ref(writer, &ref); + if (ret < 0) + goto done; + } else if ((u->flags & REF_HAVE_NEW) && ref_update_has_null_new_value(u)) { + struct reftable_ref_record ref = { + .refname = (char *)u->refname, + .update_index = ts, + .value_type = REFTABLE_REF_DELETION, + }; + + ret = reftable_writer_add_ref(writer, &ref); + if (ret < 0) + goto done; + } else if (u->flags & REF_HAVE_NEW) { + struct reftable_ref_record ref = {0}; + struct object_id peeled; + int peel_error; + + ref.refname = (char *)u->refname; + ref.update_index = ts; + + peel_error = peel_object(arg->refs->base.repo, &u->new_oid, &peeled); + if (!peel_error) { + ref.value_type = REFTABLE_REF_VAL2; + memcpy(ref.value.val2.target_value, peeled.hash, GIT_MAX_RAWSZ); + memcpy(ref.value.val2.value, u->new_oid.hash, GIT_MAX_RAWSZ); + } else if (!is_null_oid(&u->new_oid)) { + ref.value_type = REFTABLE_REF_VAL1; + memcpy(ref.value.val1, u->new_oid.hash, GIT_MAX_RAWSZ); + } + + ret = reftable_writer_add_ref(writer, &ref); + if (ret < 0) + goto done; + } + } + + /* + * Logs are written at the end so that we do not have intermixed ref + * and log blocks. + */ + if (logs) { + ret = reftable_writer_add_logs(writer, logs, logs_nr); + if (ret < 0) + goto done; + } + +done: + assert(ret != REFTABLE_API_ERROR); + for (i = 0; i < logs_nr; i++) + reftable_log_record_release(&logs[i]); + free(logs); + return ret; +} + +static int reftable_be_transaction_finish(struct ref_store *ref_store, + struct ref_transaction *transaction, + struct strbuf *err) +{ + struct reftable_transaction_data *tx_data = transaction->backend_data; + int ret = 0; + + for (size_t i = 0; i < tx_data->args_nr; i++) { + ret = reftable_addition_add(tx_data->args[i].addition, + write_transaction_table, &tx_data->args[i]); + if (ret < 0) + goto done; + + ret = reftable_addition_commit(tx_data->args[i].addition); + if (ret < 0) + goto done; + } + +done: + assert(ret != REFTABLE_API_ERROR); + free_transaction_data(tx_data); + transaction->state = REF_TRANSACTION_CLOSED; + + if (ret) { + strbuf_addf(err, _("reftable: transaction failure: %s"), + reftable_error_str(ret)); + return -1; + } + return ret; +} + +static int reftable_be_initial_transaction_commit(struct ref_store *ref_store UNUSED, + struct ref_transaction *transaction, + struct strbuf *err) +{ + return ref_transaction_commit(transaction, err); +} + +static int reftable_be_pack_refs(struct ref_store *ref_store, + struct pack_refs_opts *opts) +{ + struct reftable_ref_store *refs = + reftable_be_downcast(ref_store, REF_STORE_WRITE | REF_STORE_ODB, "pack_refs"); + struct reftable_stack *stack; + int ret; + + if (refs->err) + return refs->err; + + stack = refs->worktree_stack; + if (!stack) + stack = refs->main_stack; + + if (opts->flags & PACK_REFS_AUTO) + ret = reftable_stack_auto_compact(stack); + else + ret = reftable_stack_compact_all(stack, NULL); + if (ret < 0) { + ret = error(_("unable to compact stack: %s"), + reftable_error_str(ret)); + goto out; + } + + ret = reftable_stack_clean(stack); + if (ret) + goto out; + +out: + return ret; +} + +struct write_create_symref_arg { + struct reftable_ref_store *refs; + struct reftable_stack *stack; + struct strbuf *err; + const char *refname; + const char *target; + const char *logmsg; +}; + +struct write_copy_arg { + struct reftable_ref_store *refs; + struct reftable_stack *stack; + const char *oldname; + const char *newname; + const char *logmsg; + int delete_old; +}; + +static int write_copy_table(struct reftable_writer *writer, void *cb_data) +{ + struct write_copy_arg *arg = cb_data; + uint64_t deletion_ts, creation_ts; + struct reftable_ref_record old_ref = {0}, refs[2] = {0}; + struct reftable_log_record old_log = {0}, *logs = NULL; + struct reftable_iterator it = {0}; + struct string_list skip = STRING_LIST_INIT_NODUP; + struct ident_split committer_ident = {0}; + struct strbuf errbuf = STRBUF_INIT; + size_t logs_nr = 0, logs_alloc = 0, i; + const char *committer_info; + int ret; + + committer_info = git_committer_info(0); + if (split_ident_line(&committer_ident, committer_info, strlen(committer_info))) + BUG("failed splitting committer info"); + + if (reftable_stack_read_ref(arg->stack, arg->oldname, &old_ref)) { + ret = error(_("refname %s not found"), arg->oldname); + goto done; + } + if (old_ref.value_type == REFTABLE_REF_SYMREF) { + ret = error(_("refname %s is a symbolic ref, copying it is not supported"), + arg->oldname); + goto done; + } + + /* + * There's nothing to do in case the old and new name are the same, so + * we exit early in that case. + */ + if (!strcmp(arg->oldname, arg->newname)) { + ret = 0; + goto done; + } + + /* + * Verify that the new refname is available. + */ + if (arg->delete_old) + string_list_insert(&skip, arg->oldname); + ret = refs_verify_refname_available(&arg->refs->base, arg->newname, + NULL, &skip, &errbuf); + if (ret < 0) { + error("%s", errbuf.buf); + goto done; + } + + /* + * When deleting the old reference we have to use two update indices: + * once to delete the old ref and its reflog, and once to create the + * new ref and its reflog. They need to be staged with two separate + * indices because the new reflog needs to encode both the deletion of + * the old branch and the creation of the new branch, and we cannot do + * two changes to a reflog in a single update. + */ + deletion_ts = creation_ts = reftable_stack_next_update_index(arg->stack); + if (arg->delete_old) + creation_ts++; + reftable_writer_set_limits(writer, deletion_ts, creation_ts); + + /* + * Add the new reference. If this is a rename then we also delete the + * old reference. + */ + refs[0] = old_ref; + refs[0].refname = xstrdup(arg->newname); + refs[0].update_index = creation_ts; + if (arg->delete_old) { + refs[1].refname = xstrdup(arg->oldname); + refs[1].value_type = REFTABLE_REF_DELETION; + refs[1].update_index = deletion_ts; + } + ret = reftable_writer_add_refs(writer, refs, arg->delete_old ? 2 : 1); + if (ret < 0) + goto done; + + /* + * When deleting the old branch we need to create a reflog entry on the + * new branch name that indicates that the old branch has been deleted + * and then recreated. This is a tad weird, but matches what the files + * backend does. + */ + if (arg->delete_old) { + struct strbuf head_referent = STRBUF_INIT; + struct object_id head_oid; + int append_head_reflog; + unsigned head_type = 0; + + ALLOC_GROW(logs, logs_nr + 1, logs_alloc); + memset(&logs[logs_nr], 0, sizeof(logs[logs_nr])); + fill_reftable_log_record(&logs[logs_nr], &committer_ident); + logs[logs_nr].refname = xstrdup(arg->newname); + logs[logs_nr].update_index = deletion_ts; + logs[logs_nr].value.update.message = + xstrndup(arg->logmsg, arg->refs->write_options.block_size / 2); + memcpy(logs[logs_nr].value.update.old_hash, old_ref.value.val1, GIT_MAX_RAWSZ); + logs_nr++; + + ret = read_ref_without_reload(arg->stack, "HEAD", &head_oid, &head_referent, &head_type); + if (ret < 0) + goto done; + append_head_reflog = (head_type & REF_ISSYMREF) && !strcmp(head_referent.buf, arg->oldname); + strbuf_release(&head_referent); + + /* + * The files backend uses `refs_delete_ref()` to delete the old + * branch name, which will append a reflog entry for HEAD in + * case it points to the old branch. + */ + if (append_head_reflog) { + ALLOC_GROW(logs, logs_nr + 1, logs_alloc); + logs[logs_nr] = logs[logs_nr - 1]; + logs[logs_nr].refname = xstrdup("HEAD"); + logs[logs_nr].value.update.name = + xstrdup(logs[logs_nr].value.update.name); + logs[logs_nr].value.update.email = + xstrdup(logs[logs_nr].value.update.email); + logs[logs_nr].value.update.message = + xstrdup(logs[logs_nr].value.update.message); + logs_nr++; + } + } + + /* + * Create the reflog entry for the newly created branch. + */ + ALLOC_GROW(logs, logs_nr + 1, logs_alloc); + memset(&logs[logs_nr], 0, sizeof(logs[logs_nr])); + fill_reftable_log_record(&logs[logs_nr], &committer_ident); + logs[logs_nr].refname = xstrdup(arg->newname); + logs[logs_nr].update_index = creation_ts; + logs[logs_nr].value.update.message = + xstrndup(arg->logmsg, arg->refs->write_options.block_size / 2); + memcpy(logs[logs_nr].value.update.new_hash, old_ref.value.val1, GIT_MAX_RAWSZ); + logs_nr++; + + /* + * In addition to writing the reflog entry for the new branch, we also + * copy over all log entries from the old reflog. Last but not least, + * when renaming we also have to delete all the old reflog entries. + */ + reftable_stack_init_log_iterator(arg->stack, &it); + ret = reftable_iterator_seek_log(&it, arg->oldname); + if (ret < 0) + goto done; + + while (1) { + ret = reftable_iterator_next_log(&it, &old_log); + if (ret < 0) + goto done; + if (ret > 0 || strcmp(old_log.refname, arg->oldname)) { + ret = 0; + break; + } + + free(old_log.refname); + + /* + * Copy over the old reflog entry with the new refname. + */ + ALLOC_GROW(logs, logs_nr + 1, logs_alloc); + logs[logs_nr] = old_log; + logs[logs_nr].refname = xstrdup(arg->newname); + logs_nr++; + + /* + * Delete the old reflog entry in case we are renaming. + */ + if (arg->delete_old) { + ALLOC_GROW(logs, logs_nr + 1, logs_alloc); + memset(&logs[logs_nr], 0, sizeof(logs[logs_nr])); + logs[logs_nr].refname = xstrdup(arg->oldname); + logs[logs_nr].value_type = REFTABLE_LOG_DELETION; + logs[logs_nr].update_index = old_log.update_index; + logs_nr++; + } + + /* + * Transfer ownership of the log record we're iterating over to + * the array of log records. Otherwise, the pointers would get + * free'd or reallocated by the iterator. + */ + memset(&old_log, 0, sizeof(old_log)); + } + + ret = reftable_writer_add_logs(writer, logs, logs_nr); + if (ret < 0) + goto done; + +done: + assert(ret != REFTABLE_API_ERROR); + reftable_iterator_destroy(&it); + string_list_clear(&skip, 0); + strbuf_release(&errbuf); + for (i = 0; i < logs_nr; i++) + reftable_log_record_release(&logs[i]); + free(logs); + for (i = 0; i < ARRAY_SIZE(refs); i++) + reftable_ref_record_release(&refs[i]); + reftable_ref_record_release(&old_ref); + reftable_log_record_release(&old_log); + return ret; +} + +static int reftable_be_rename_ref(struct ref_store *ref_store, + const char *oldrefname, + const char *newrefname, + const char *logmsg) +{ + struct reftable_ref_store *refs = + reftable_be_downcast(ref_store, REF_STORE_WRITE, "rename_ref"); + struct reftable_stack *stack = stack_for(refs, newrefname, &newrefname); + struct write_copy_arg arg = { + .refs = refs, + .stack = stack, + .oldname = oldrefname, + .newname = newrefname, + .logmsg = logmsg, + .delete_old = 1, + }; + int ret; + + ret = refs->err; + if (ret < 0) + goto done; + + ret = reftable_stack_reload(stack); + if (ret) + goto done; + ret = reftable_stack_add(stack, &write_copy_table, &arg); + +done: + assert(ret != REFTABLE_API_ERROR); + return ret; +} + +static int reftable_be_copy_ref(struct ref_store *ref_store, + const char *oldrefname, + const char *newrefname, + const char *logmsg) +{ + struct reftable_ref_store *refs = + reftable_be_downcast(ref_store, REF_STORE_WRITE, "copy_ref"); + struct reftable_stack *stack = stack_for(refs, newrefname, &newrefname); + struct write_copy_arg arg = { + .refs = refs, + .stack = stack, + .oldname = oldrefname, + .newname = newrefname, + .logmsg = logmsg, + }; + int ret; + + ret = refs->err; + if (ret < 0) + goto done; + + ret = reftable_stack_reload(stack); + if (ret) + goto done; + ret = reftable_stack_add(stack, &write_copy_table, &arg); + +done: + assert(ret != REFTABLE_API_ERROR); + return ret; +} + +struct reftable_reflog_iterator { + struct ref_iterator base; + struct reftable_ref_store *refs; + struct reftable_iterator iter; + struct reftable_log_record log; + struct strbuf last_name; + int err; +}; + +static int reftable_reflog_iterator_advance(struct ref_iterator *ref_iterator) +{ + struct reftable_reflog_iterator *iter = + (struct reftable_reflog_iterator *)ref_iterator; + + while (!iter->err) { + iter->err = reftable_iterator_next_log(&iter->iter, &iter->log); + if (iter->err) + break; + + /* + * We want the refnames that we have reflogs for, so we skip if + * we've already produced this name. This could be faster by + * seeking directly to reflog@update_index==0. + */ + if (!strcmp(iter->log.refname, iter->last_name.buf)) + continue; + + if (check_refname_format(iter->log.refname, + REFNAME_ALLOW_ONELEVEL)) + continue; + + strbuf_reset(&iter->last_name); + strbuf_addstr(&iter->last_name, iter->log.refname); + iter->base.refname = iter->log.refname; + + break; + } + + if (iter->err > 0) { + if (ref_iterator_abort(ref_iterator) != ITER_DONE) + return ITER_ERROR; + return ITER_DONE; + } + + if (iter->err < 0) { + ref_iterator_abort(ref_iterator); + return ITER_ERROR; + } + + return ITER_OK; +} + +static int reftable_reflog_iterator_peel(struct ref_iterator *ref_iterator, + struct object_id *peeled) +{ + BUG("reftable reflog iterator cannot be peeled"); + return -1; +} + +static int reftable_reflog_iterator_abort(struct ref_iterator *ref_iterator) +{ + struct reftable_reflog_iterator *iter = + (struct reftable_reflog_iterator *)ref_iterator; + reftable_log_record_release(&iter->log); + reftable_iterator_destroy(&iter->iter); + strbuf_release(&iter->last_name); + free(iter); + return ITER_DONE; +} + +static struct ref_iterator_vtable reftable_reflog_iterator_vtable = { + .advance = reftable_reflog_iterator_advance, + .peel = reftable_reflog_iterator_peel, + .abort = reftable_reflog_iterator_abort +}; + +static struct reftable_reflog_iterator *reflog_iterator_for_stack(struct reftable_ref_store *refs, + struct reftable_stack *stack) +{ + struct reftable_reflog_iterator *iter; + int ret; + + iter = xcalloc(1, sizeof(*iter)); + base_ref_iterator_init(&iter->base, &reftable_reflog_iterator_vtable); + strbuf_init(&iter->last_name, 0); + iter->refs = refs; + + ret = refs->err; + if (ret) + goto done; + + ret = reftable_stack_reload(stack); + if (ret < 0) + goto done; + + reftable_stack_init_log_iterator(stack, &iter->iter); + ret = reftable_iterator_seek_log(&iter->iter, ""); + if (ret < 0) + goto done; + +done: + iter->err = ret; + return iter; +} + +static struct ref_iterator *reftable_be_reflog_iterator_begin(struct ref_store *ref_store) +{ + struct reftable_ref_store *refs = + reftable_be_downcast(ref_store, REF_STORE_READ, "reflog_iterator_begin"); + struct reftable_reflog_iterator *main_iter, *worktree_iter; + + main_iter = reflog_iterator_for_stack(refs, refs->main_stack); + if (!refs->worktree_stack) + return &main_iter->base; + + worktree_iter = reflog_iterator_for_stack(refs, refs->worktree_stack); + + return merge_ref_iterator_begin(&worktree_iter->base, &main_iter->base, + ref_iterator_select, NULL); +} + +static int yield_log_record(struct reftable_log_record *log, + each_reflog_ent_fn fn, + void *cb_data) +{ + struct object_id old_oid, new_oid; + const char *full_committer; + + oidread(&old_oid, log->value.update.old_hash, the_repository->hash_algo); + oidread(&new_oid, log->value.update.new_hash, the_repository->hash_algo); + + /* + * When both the old object ID and the new object ID are null + * then this is the reflog existence marker. The caller must + * not be aware of it. + */ + if (is_null_oid(&old_oid) && is_null_oid(&new_oid)) + return 0; + + full_committer = fmt_ident(log->value.update.name, log->value.update.email, + WANT_COMMITTER_IDENT, NULL, IDENT_NO_DATE); + return fn(&old_oid, &new_oid, full_committer, + log->value.update.time, log->value.update.tz_offset, + log->value.update.message, cb_data); +} + +static int reftable_be_for_each_reflog_ent_reverse(struct ref_store *ref_store, + const char *refname, + each_reflog_ent_fn fn, + void *cb_data) +{ + struct reftable_ref_store *refs = + reftable_be_downcast(ref_store, REF_STORE_READ, "for_each_reflog_ent_reverse"); + struct reftable_stack *stack = stack_for(refs, refname, &refname); + struct reftable_log_record log = {0}; + struct reftable_iterator it = {0}; + int ret; + + if (refs->err < 0) + return refs->err; + + reftable_stack_init_log_iterator(stack, &it); + ret = reftable_iterator_seek_log(&it, refname); + while (!ret) { + ret = reftable_iterator_next_log(&it, &log); + if (ret < 0) + break; + if (ret > 0 || strcmp(log.refname, refname)) { + ret = 0; + break; + } + + ret = yield_log_record(&log, fn, cb_data); + if (ret) + break; + } + + reftable_log_record_release(&log); + reftable_iterator_destroy(&it); + return ret; +} + +static int reftable_be_for_each_reflog_ent(struct ref_store *ref_store, + const char *refname, + each_reflog_ent_fn fn, + void *cb_data) +{ + struct reftable_ref_store *refs = + reftable_be_downcast(ref_store, REF_STORE_READ, "for_each_reflog_ent"); + struct reftable_stack *stack = stack_for(refs, refname, &refname); + struct reftable_log_record *logs = NULL; + struct reftable_iterator it = {0}; + size_t logs_alloc = 0, logs_nr = 0, i; + int ret; + + if (refs->err < 0) + return refs->err; + + reftable_stack_init_log_iterator(stack, &it); + ret = reftable_iterator_seek_log(&it, refname); + while (!ret) { + struct reftable_log_record log = {0}; + + ret = reftable_iterator_next_log(&it, &log); + if (ret < 0) + goto done; + if (ret > 0 || strcmp(log.refname, refname)) { + reftable_log_record_release(&log); + ret = 0; + break; + } + + ALLOC_GROW(logs, logs_nr + 1, logs_alloc); + logs[logs_nr++] = log; + } + + for (i = logs_nr; i--;) { + ret = yield_log_record(&logs[i], fn, cb_data); + if (ret) + goto done; + } + +done: + reftable_iterator_destroy(&it); + for (i = 0; i < logs_nr; i++) + reftable_log_record_release(&logs[i]); + free(logs); + return ret; +} + +static int reftable_be_reflog_exists(struct ref_store *ref_store, + const char *refname) +{ + struct reftable_ref_store *refs = + reftable_be_downcast(ref_store, REF_STORE_READ, "reflog_exists"); + struct reftable_stack *stack = stack_for(refs, refname, &refname); + struct reftable_log_record log = {0}; + struct reftable_iterator it = {0}; + int ret; + + ret = refs->err; + if (ret < 0) + goto done; + + ret = reftable_stack_reload(stack); + if (ret < 0) + goto done; + + reftable_stack_init_log_iterator(stack, &it); + ret = reftable_iterator_seek_log(&it, refname); + if (ret < 0) + goto done; + + /* + * Check whether we get at least one log record for the given ref name. + * If so, the reflog exists, otherwise it doesn't. + */ + ret = reftable_iterator_next_log(&it, &log); + if (ret < 0) + goto done; + if (ret > 0) { + ret = 0; + goto done; + } + + ret = strcmp(log.refname, refname) == 0; + +done: + reftable_iterator_destroy(&it); + reftable_log_record_release(&log); + if (ret < 0) + ret = 0; + return ret; +} + +struct write_reflog_existence_arg { + struct reftable_ref_store *refs; + const char *refname; + struct reftable_stack *stack; +}; + +static int write_reflog_existence_table(struct reftable_writer *writer, + void *cb_data) +{ + struct write_reflog_existence_arg *arg = cb_data; + uint64_t ts = reftable_stack_next_update_index(arg->stack); + struct reftable_log_record log = {0}; + int ret; + + ret = reftable_stack_read_log(arg->stack, arg->refname, &log); + if (ret <= 0) + goto done; + + reftable_writer_set_limits(writer, ts, ts); + + /* + * The existence entry has both old and new object ID set to the the + * null object ID. Our iterators are aware of this and will not present + * them to their callers. + */ + log.refname = xstrdup(arg->refname); + log.update_index = ts; + log.value_type = REFTABLE_LOG_UPDATE; + ret = reftable_writer_add_log(writer, &log); + +done: + assert(ret != REFTABLE_API_ERROR); + reftable_log_record_release(&log); + return ret; +} + +static int reftable_be_create_reflog(struct ref_store *ref_store, + const char *refname, + struct strbuf *errmsg) +{ + struct reftable_ref_store *refs = + reftable_be_downcast(ref_store, REF_STORE_WRITE, "create_reflog"); + struct reftable_stack *stack = stack_for(refs, refname, &refname); + struct write_reflog_existence_arg arg = { + .refs = refs, + .stack = stack, + .refname = refname, + }; + int ret; + + ret = refs->err; + if (ret < 0) + goto done; + + ret = reftable_stack_reload(stack); + if (ret) + goto done; + + ret = reftable_stack_add(stack, &write_reflog_existence_table, &arg); + +done: + return ret; +} + +struct write_reflog_delete_arg { + struct reftable_stack *stack; + const char *refname; +}; + +static int write_reflog_delete_table(struct reftable_writer *writer, void *cb_data) +{ + struct write_reflog_delete_arg *arg = cb_data; + struct reftable_log_record log = {0}, tombstone = {0}; + struct reftable_iterator it = {0}; + uint64_t ts = reftable_stack_next_update_index(arg->stack); + int ret; + + reftable_writer_set_limits(writer, ts, ts); + + reftable_stack_init_log_iterator(arg->stack, &it); + + /* + * In order to delete a table we need to delete all reflog entries one + * by one. This is inefficient, but the reftable format does not have a + * better marker right now. + */ + ret = reftable_iterator_seek_log(&it, arg->refname); + while (ret == 0) { + ret = reftable_iterator_next_log(&it, &log); + if (ret < 0) + break; + if (ret > 0 || strcmp(log.refname, arg->refname)) { + ret = 0; + break; + } + + tombstone.refname = (char *)arg->refname; + tombstone.value_type = REFTABLE_LOG_DELETION; + tombstone.update_index = log.update_index; + + ret = reftable_writer_add_log(writer, &tombstone); + } + + reftable_log_record_release(&log); + reftable_iterator_destroy(&it); + return ret; +} + +static int reftable_be_delete_reflog(struct ref_store *ref_store, + const char *refname) +{ + struct reftable_ref_store *refs = + reftable_be_downcast(ref_store, REF_STORE_WRITE, "delete_reflog"); + struct reftable_stack *stack = stack_for(refs, refname, &refname); + struct write_reflog_delete_arg arg = { + .stack = stack, + .refname = refname, + }; + int ret; + + ret = reftable_stack_reload(stack); + if (ret) + return ret; + ret = reftable_stack_add(stack, &write_reflog_delete_table, &arg); + + assert(ret != REFTABLE_API_ERROR); + return ret; +} + +struct reflog_expiry_arg { + struct reftable_ref_store *refs; + struct reftable_stack *stack; + struct reftable_log_record *records; + struct object_id update_oid; + const char *refname; + size_t len; +}; + +static int write_reflog_expiry_table(struct reftable_writer *writer, void *cb_data) +{ + struct reflog_expiry_arg *arg = cb_data; + uint64_t ts = reftable_stack_next_update_index(arg->stack); + uint64_t live_records = 0; + size_t i; + int ret; + + for (i = 0; i < arg->len; i++) + if (arg->records[i].value_type == REFTABLE_LOG_UPDATE) + live_records++; + + reftable_writer_set_limits(writer, ts, ts); + + if (!is_null_oid(&arg->update_oid)) { + struct reftable_ref_record ref = {0}; + struct object_id peeled; + + ref.refname = (char *)arg->refname; + ref.update_index = ts; + + if (!peel_object(arg->refs->base.repo, &arg->update_oid, &peeled)) { + ref.value_type = REFTABLE_REF_VAL2; + memcpy(ref.value.val2.target_value, peeled.hash, GIT_MAX_RAWSZ); + memcpy(ref.value.val2.value, arg->update_oid.hash, GIT_MAX_RAWSZ); + } else { + ref.value_type = REFTABLE_REF_VAL1; + memcpy(ref.value.val1, arg->update_oid.hash, GIT_MAX_RAWSZ); + } + + ret = reftable_writer_add_ref(writer, &ref); + if (ret < 0) + return ret; + } + + /* + * When there are no more entries left in the reflog we empty it + * completely, but write a placeholder reflog entry that indicates that + * the reflog still exists. + */ + if (!live_records) { + struct reftable_log_record log = { + .refname = (char *)arg->refname, + .value_type = REFTABLE_LOG_UPDATE, + .update_index = ts, + }; + + ret = reftable_writer_add_log(writer, &log); + if (ret) + return ret; + } + + for (i = 0; i < arg->len; i++) { + ret = reftable_writer_add_log(writer, &arg->records[i]); + if (ret) + return ret; + } + + return 0; +} + +static int reftable_be_reflog_expire(struct ref_store *ref_store, + const char *refname, + 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) +{ + /* + * For log expiry, we write tombstones for every single reflog entry + * that is to be expired. This means that the entries are still + * retrievable by delving into the stack, and expiring entries + * paradoxically takes extra memory. This memory is only reclaimed when + * compacting the reftable stack. + * + * It would be better if the refs backend supported an API that sets a + * criterion for all refs, passing the criterion to pack_refs(). + * + * On the plus side, because we do the expiration per ref, we can easily + * insert the reflog existence dummies. + */ + struct reftable_ref_store *refs = + reftable_be_downcast(ref_store, REF_STORE_WRITE, "reflog_expire"); + struct reftable_stack *stack = stack_for(refs, refname, &refname); + struct reftable_log_record *logs = NULL; + struct reftable_log_record *rewritten = NULL; + struct reftable_ref_record ref_record = {0}; + struct reftable_iterator it = {0}; + struct reftable_addition *add = NULL; + struct reflog_expiry_arg arg = {0}; + struct object_id oid = {0}; + uint8_t *last_hash = NULL; + size_t logs_nr = 0, logs_alloc = 0, i; + int ret; + + if (refs->err < 0) + return refs->err; + + ret = reftable_stack_reload(stack); + if (ret < 0) + goto done; + + reftable_stack_init_log_iterator(stack, &it); + + ret = reftable_iterator_seek_log(&it, refname); + if (ret < 0) + goto done; + + ret = reftable_stack_new_addition(&add, stack); + if (ret < 0) + goto done; + + ret = reftable_stack_read_ref(stack, refname, &ref_record); + if (ret < 0) + goto done; + if (reftable_ref_record_val1(&ref_record)) + oidread(&oid, reftable_ref_record_val1(&ref_record), + the_repository->hash_algo); + prepare_fn(refname, &oid, policy_cb_data); + + while (1) { + struct reftable_log_record log = {0}; + struct object_id old_oid, new_oid; + + ret = reftable_iterator_next_log(&it, &log); + if (ret < 0) + goto done; + if (ret > 0 || strcmp(log.refname, refname)) { + reftable_log_record_release(&log); + break; + } + + oidread(&old_oid, log.value.update.old_hash, + the_repository->hash_algo); + oidread(&new_oid, log.value.update.new_hash, + the_repository->hash_algo); + + /* + * Skip over the reflog existence marker. We will add it back + * in when there are no live reflog records. + */ + if (is_null_oid(&old_oid) && is_null_oid(&new_oid)) { + reftable_log_record_release(&log); + continue; + } + + ALLOC_GROW(logs, logs_nr + 1, logs_alloc); + logs[logs_nr++] = log; + } + + /* + * We need to rewrite all reflog entries according to the pruning + * callback function: + * + * - If a reflog entry shall be pruned we mark the record for + * deletion. + * + * - Otherwise we may have to rewrite the chain of reflog entries so + * that gaps created by just-deleted records get backfilled. + */ + CALLOC_ARRAY(rewritten, logs_nr); + for (i = logs_nr; i--;) { + struct reftable_log_record *dest = &rewritten[i]; + struct object_id old_oid, new_oid; + + *dest = logs[i]; + oidread(&old_oid, logs[i].value.update.old_hash, + the_repository->hash_algo); + oidread(&new_oid, logs[i].value.update.new_hash, + the_repository->hash_algo); + + if (should_prune_fn(&old_oid, &new_oid, logs[i].value.update.email, + (timestamp_t)logs[i].value.update.time, + logs[i].value.update.tz_offset, + logs[i].value.update.message, + policy_cb_data)) { + dest->value_type = REFTABLE_LOG_DELETION; + } else { + if ((flags & EXPIRE_REFLOGS_REWRITE) && last_hash) + memcpy(dest->value.update.old_hash, last_hash, GIT_MAX_RAWSZ); + last_hash = logs[i].value.update.new_hash; + } + } + + if (flags & EXPIRE_REFLOGS_UPDATE_REF && last_hash && + reftable_ref_record_val1(&ref_record)) + oidread(&arg.update_oid, last_hash, the_repository->hash_algo); + + arg.refs = refs; + arg.records = rewritten; + arg.len = logs_nr; + arg.stack = stack, + arg.refname = refname, + + ret = reftable_addition_add(add, &write_reflog_expiry_table, &arg); + if (ret < 0) + goto done; + + /* + * Future improvement: we could skip writing records that were + * not changed. + */ + if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) + ret = reftable_addition_commit(add); + +done: + if (add) + cleanup_fn(policy_cb_data); + assert(ret != REFTABLE_API_ERROR); + + reftable_ref_record_release(&ref_record); + reftable_iterator_destroy(&it); + reftable_addition_destroy(add); + for (i = 0; i < logs_nr; i++) + reftable_log_record_release(&logs[i]); + free(logs); + free(rewritten); + return ret; +} + +struct ref_storage_be refs_be_reftable = { + .name = "reftable", + .init = reftable_be_init, + .release = reftable_be_release, + .create_on_disk = reftable_be_create_on_disk, + .remove_on_disk = reftable_be_remove_on_disk, + + .transaction_prepare = reftable_be_transaction_prepare, + .transaction_finish = reftable_be_transaction_finish, + .transaction_abort = reftable_be_transaction_abort, + .initial_transaction_commit = reftable_be_initial_transaction_commit, + + .pack_refs = reftable_be_pack_refs, + .rename_ref = reftable_be_rename_ref, + .copy_ref = reftable_be_copy_ref, + + .iterator_begin = reftable_be_iterator_begin, + .read_raw_ref = reftable_be_read_raw_ref, + .read_symbolic_ref = reftable_be_read_symbolic_ref, + + .reflog_iterator_begin = reftable_be_reflog_iterator_begin, + .for_each_reflog_ent = reftable_be_for_each_reflog_ent, + .for_each_reflog_ent_reverse = reftable_be_for_each_reflog_ent_reverse, + .reflog_exists = reftable_be_reflog_exists, + .create_reflog = reftable_be_create_reflog, + .delete_reflog = reftable_be_delete_reflog, + .reflog_expire = reftable_be_reflog_expire, +}; |