blob: 3a75d63eb5f4d05f7c8df719e39a1b3d6719fec5 [file] [log] [blame]
#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));
} 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);
break;
case REFTABLE_REF_VAL2:
oidread(&iter->oid, iter->ref.value.val2.value);
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);
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);
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);
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,
&current_oid, &referent, &u->type);
if (ret < 0)
goto done;
if (ret > 0 && (!(u->flags & REF_HAVE_OLD) || is_null_oid(&u->old_oid))) {
/*
* 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,
&current_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,
&current_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_oid, &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 (ref_update_check_old_target(referent.buf, u, err)) {
ret = -1;
goto done;
}
} else if ((u->flags & REF_HAVE_OLD) && !oideq(&current_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(&current_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(&current_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(&current_oid, &u->new_oid))) {
ret = queue_transaction_update(refs, tx_data, u,
&current_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);
oidread(&new_oid, log->value.update.new_hash);
/*
* 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));
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);
oidread(&new_oid, log.value.update.new_hash);
/*
* 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);
oidread(&new_oid, logs[i].value.update.new_hash);
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);
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,
};