* [PATCH v2 1/6] refs: construct transaction using a _begin callback
2023-09-20 13:02 ` [PATCH v2 0/6] RFC: simple " Han-Wen Nienhuys via GitGitGadget
@ 2023-09-20 13:02 ` Han-Wen Nienhuys via GitGitGadget
2023-09-20 13:02 ` [PATCH v2 2/6] refs: wrap transaction in a debug-specific transaction Han-Wen Nienhuys via GitGitGadget
` (5 subsequent siblings)
6 siblings, 0 replies; 15+ messages in thread
From: Han-Wen Nienhuys via GitGitGadget @ 2023-09-20 13:02 UTC (permalink / raw)
To: git; +Cc: Han-Wen Nienhuys, Han-Wen Nienhuys, Han-Wen Nienhuys
From: Han-Wen Nienhuys <hanwen@google.com>
This prepares for taking locks on constructing the transaction.
Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
---
refs.c | 8 +++-----
refs/debug.c | 8 ++++++++
refs/files-backend.c | 8 ++++++++
refs/packed-backend.c | 9 +++++++++
refs/refs-internal.h | 4 ++++
5 files changed, 32 insertions(+), 5 deletions(-)
diff --git a/refs.c b/refs.c
index fcae5dddc60..f7ba3e56284 100644
--- a/refs.c
+++ b/refs.c
@@ -1129,11 +1129,9 @@ int read_ref_at(struct ref_store *refs, const char *refname,
struct ref_transaction *ref_store_transaction_begin(struct ref_store *refs,
struct strbuf *err)
{
- struct ref_transaction *tr;
- assert(err);
-
- CALLOC_ARRAY(tr, 1);
- tr->ref_store = refs;
+ struct ref_transaction *tr = refs->be->transaction_begin(refs, err);
+ if (tr)
+ tr->ref_store = refs;
return tr;
}
diff --git a/refs/debug.c b/refs/debug.c
index b7ffc4ce67e..95fb3eb4430 100644
--- a/refs/debug.c
+++ b/refs/debug.c
@@ -41,6 +41,13 @@ static int debug_init_db(struct ref_store *refs, struct strbuf *err)
return res;
}
+static struct ref_transaction *debug_transaction_begin(struct ref_store *ref_store,
+ struct strbuf *err) {
+ struct ref_transaction *tr;
+ CALLOC_ARRAY(tr, 1);
+ return tr;
+}
+
static int debug_transaction_prepare(struct ref_store *refs,
struct ref_transaction *transaction,
struct strbuf *err)
@@ -451,6 +458,7 @@ struct ref_storage_be refs_be_debug = {
* has a function we should also have a wrapper for it here.
* Test the output with "GIT_TRACE_REFS=1".
*/
+ .transaction_begin = debug_transaction_begin,
.transaction_prepare = debug_transaction_prepare,
.transaction_finish = debug_transaction_finish,
.transaction_abort = debug_transaction_abort,
diff --git a/refs/files-backend.c b/refs/files-backend.c
index 341354182bb..d83eea8b408 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -2681,6 +2681,13 @@ static void files_transaction_cleanup(struct files_ref_store *refs,
transaction->state = REF_TRANSACTION_CLOSED;
}
+static struct ref_transaction *files_transaction_begin(struct ref_store *ref_store,
+ struct strbuf *err) {
+ struct ref_transaction *tr;
+ CALLOC_ARRAY(tr, 1);
+ return tr;
+}
+
static int files_transaction_prepare(struct ref_store *ref_store,
struct ref_transaction *transaction,
struct strbuf *err)
@@ -3297,6 +3304,7 @@ struct ref_storage_be refs_be_files = {
.name = "files",
.init = files_ref_store_create,
.init_db = files_init_db,
+ .transaction_begin = files_transaction_begin,
.transaction_prepare = files_transaction_prepare,
.transaction_finish = files_transaction_finish,
.transaction_abort = files_transaction_abort,
diff --git a/refs/packed-backend.c b/refs/packed-backend.c
index 59c78d7941f..4f5b1025605 100644
--- a/refs/packed-backend.c
+++ b/refs/packed-backend.c
@@ -1580,6 +1580,14 @@ static void packed_transaction_cleanup(struct packed_ref_store *refs,
transaction->state = REF_TRANSACTION_CLOSED;
}
+
+static struct ref_transaction *packed_transaction_begin(struct ref_store *ref_store,
+ struct strbuf *err) {
+ struct ref_transaction *tr;
+ CALLOC_ARRAY(tr, 1);
+ return tr;
+}
+
static int packed_transaction_prepare(struct ref_store *ref_store,
struct ref_transaction *transaction,
struct strbuf *err)
@@ -1758,6 +1766,7 @@ struct ref_storage_be refs_be_packed = {
.name = "packed",
.init = packed_ref_store_create,
.init_db = packed_init_db,
+ .transaction_begin = packed_transaction_begin,
.transaction_prepare = packed_transaction_prepare,
.transaction_finish = packed_transaction_finish,
.transaction_abort = packed_transaction_abort,
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index 9db8aec4da8..0a15e8a2ac8 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -531,6 +531,9 @@ typedef struct ref_store *ref_store_init_fn(struct repository *repo,
typedef int ref_init_db_fn(struct ref_store *refs, struct strbuf *err);
+typedef struct ref_transaction *ref_transaction_begin_fn(struct ref_store *refs,
+ struct strbuf *err);
+
typedef int ref_transaction_prepare_fn(struct ref_store *refs,
struct ref_transaction *transaction,
struct strbuf *err);
@@ -670,6 +673,7 @@ struct ref_storage_be {
ref_store_init_fn *init;
ref_init_db_fn *init_db;
+ ref_transaction_begin_fn *transaction_begin;
ref_transaction_prepare_fn *transaction_prepare;
ref_transaction_finish_fn *transaction_finish;
ref_transaction_abort_fn *transaction_abort;
--
gitgitgadget
^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH v2 2/6] refs: wrap transaction in a debug-specific transaction
2023-09-20 13:02 ` [PATCH v2 0/6] RFC: simple " Han-Wen Nienhuys via GitGitGadget
2023-09-20 13:02 ` [PATCH v2 1/6] refs: construct transaction using a _begin callback Han-Wen Nienhuys via GitGitGadget
@ 2023-09-20 13:02 ` Han-Wen Nienhuys via GitGitGadget
2023-09-20 13:02 ` [PATCH v2 3/6] refs: push lock management into packed backend Han-Wen Nienhuys via GitGitGadget
` (4 subsequent siblings)
6 siblings, 0 replies; 15+ messages in thread
From: Han-Wen Nienhuys via GitGitGadget @ 2023-09-20 13:02 UTC (permalink / raw)
To: git; +Cc: Han-Wen Nienhuys, Han-Wen Nienhuys, Han-Wen Nienhuys
From: Han-Wen Nienhuys <hanwen@google.com>
This ensures that all transaction methods are properly printed. This is
needed because the callbacks are called as
transaction->ref_store->backend->$CALLBACK.
Originally, there was a hacky workaround which overwrote
transaction->ref_store before passing it into the non-debug prepare()
callback. This would print something for the prepare function, but not
for abort/finish functions.
Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
---
refs/debug.c | 83 +++++++++++++++++++++++++++++++++++++---------------
1 file changed, 59 insertions(+), 24 deletions(-)
diff --git a/refs/debug.c b/refs/debug.c
index 95fb3eb4430..30509da4b89 100644
--- a/refs/debug.c
+++ b/refs/debug.c
@@ -43,25 +43,18 @@ static int debug_init_db(struct ref_store *refs, struct strbuf *err)
static struct ref_transaction *debug_transaction_begin(struct ref_store *ref_store,
struct strbuf *err) {
+ struct debug_ref_store *drefs = (struct debug_ref_store *)ref_store;
struct ref_transaction *tr;
+ struct ref_transaction *sub_tr = ref_store_transaction_begin(drefs->refs, err);
+ trace_printf_key(&trace_refs, "transaction_begin: %s\n", err->buf);
+ if (!sub_tr) {
+ return NULL;
+ }
CALLOC_ARRAY(tr, 1);
+ tr->backend_data = sub_tr;
return tr;
}
-static int debug_transaction_prepare(struct ref_store *refs,
- struct ref_transaction *transaction,
- struct strbuf *err)
-{
- struct debug_ref_store *drefs = (struct debug_ref_store *)refs;
- int res;
- transaction->ref_store = drefs->refs;
- res = drefs->refs->be->transaction_prepare(drefs->refs, transaction,
- err);
- trace_printf_key(&trace_refs, "transaction_prepare: %d \"%s\"\n", res,
- err->buf);
- return res;
-}
-
static void print_update(int i, const char *refname,
const struct object_id *old_oid,
const struct object_id *new_oid, unsigned int flags,
@@ -77,20 +70,59 @@ static void print_update(int i, const char *refname,
type &= 0xf; /* see refs.h REF_* */
flags &= REF_HAVE_NEW | REF_HAVE_OLD | REF_NO_DEREF |
REF_FORCE_CREATE_REFLOG;
- trace_printf_key(&trace_refs, "%d: %s %s -> %s (F=0x%x, T=0x%x) \"%s\"\n", i, refname,
+ trace_printf_key(&trace_refs, " %d: '%s' %s -> %s (F=0x%x, T=0x%x) \"%s\"\n", i, refname,
o, n, flags, type, msg);
}
-static void print_transaction(struct ref_transaction *transaction)
+static void print_transaction(struct ref_transaction *transaction,
+ const char *action,
+ int res, struct strbuf *err)
{
int i;
- trace_printf_key(&trace_refs, "transaction {\n");
+ trace_printf_key(&trace_refs, "transaction %s {\n", action);
for (i = 0; i < transaction->nr; i++) {
struct ref_update *u = transaction->updates[i];
print_update(i, u->refname, &u->old_oid, &u->new_oid, u->flags,
u->type, u->msg);
}
- trace_printf_key(&trace_refs, "}\n");
+ trace_printf_key(&trace_refs, "}: %d '%s'\n", res, err->buf);
+}
+
+static void copy_update(struct ref_update *dst,
+ struct ref_update *src) {
+ /* dst->refname is const char; can't assign structs */
+ dst->new_oid = src->new_oid;
+ dst->old_oid = src->old_oid;
+ dst->flags = src->flags;
+ dst->backend_data = NULL;
+ dst->type = src->type;
+ dst->msg = xstrdup(src->msg);
+ dst->parent_update = NULL;
+ /* refname is done as part of FLEX_ALLOC_STR. */
+}
+
+static int debug_transaction_prepare(struct ref_store *refs,
+ struct ref_transaction *transaction,
+ struct strbuf *err)
+{
+ struct debug_ref_store *drefs = (struct debug_ref_store *)refs;
+ struct ref_transaction *sub_transaction = transaction->backend_data;
+ int res;
+ int i;
+
+ ALLOC_GROW(sub_transaction->updates, transaction->nr, sub_transaction->alloc);
+ for (i = 0; i < transaction->nr; i++) {
+ struct ref_update *up = transaction->updates[i];
+ struct ref_update *sub_up;
+ FLEX_ALLOC_STR(sub_up, refname, up->refname);
+ copy_update(sub_up, up);
+ sub_transaction->updates[i] = sub_up;
+ }
+ sub_transaction->nr = transaction->nr;
+ res = drefs->refs->be->transaction_prepare(drefs->refs, sub_transaction,
+ err);
+ print_transaction(sub_transaction, "prepare", res, err);
+ return res;
}
static int debug_transaction_finish(struct ref_store *refs,
@@ -98,12 +130,11 @@ static int debug_transaction_finish(struct ref_store *refs,
struct strbuf *err)
{
struct debug_ref_store *drefs = (struct debug_ref_store *)refs;
+ struct ref_transaction *sub_transaction = transaction->backend_data;
int res;
- transaction->ref_store = drefs->refs;
- res = drefs->refs->be->transaction_finish(drefs->refs, transaction,
+ res = drefs->refs->be->transaction_finish(drefs->refs, sub_transaction,
err);
- print_transaction(transaction);
- trace_printf_key(&trace_refs, "finish: %d\n", res);
+ print_transaction(sub_transaction, "finish", res, err);
return res;
}
@@ -112,9 +143,11 @@ static int debug_transaction_abort(struct ref_store *refs,
struct strbuf *err)
{
struct debug_ref_store *drefs = (struct debug_ref_store *)refs;
+ struct ref_transaction *sub_transaction = transaction->backend_data;
int res;
transaction->ref_store = drefs->refs;
- res = drefs->refs->be->transaction_abort(drefs->refs, transaction, err);
+ res = drefs->refs->be->transaction_abort(drefs->refs, sub_transaction, err);
+ print_transaction(sub_transaction, "abort", res, err);
return res;
}
@@ -123,10 +156,12 @@ static int debug_initial_transaction_commit(struct ref_store *refs,
struct strbuf *err)
{
struct debug_ref_store *drefs = (struct debug_ref_store *)refs;
+ struct ref_transaction *sub_transaction = transaction->backend_data;
int res;
transaction->ref_store = drefs->refs;
res = drefs->refs->be->initial_transaction_commit(drefs->refs,
- transaction, err);
+ sub_transaction, err);
+ print_transaction(sub_transaction, "commit", res, err);
return res;
}
--
gitgitgadget
^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH v2 3/6] refs: push lock management into packed backend
2023-09-20 13:02 ` [PATCH v2 0/6] RFC: simple " Han-Wen Nienhuys via GitGitGadget
2023-09-20 13:02 ` [PATCH v2 1/6] refs: construct transaction using a _begin callback Han-Wen Nienhuys via GitGitGadget
2023-09-20 13:02 ` [PATCH v2 2/6] refs: wrap transaction in a debug-specific transaction Han-Wen Nienhuys via GitGitGadget
@ 2023-09-20 13:02 ` Han-Wen Nienhuys via GitGitGadget
2023-09-20 13:02 ` [PATCH v2 4/6] refs: move is_packed_transaction_needed out of packed-backend.c Han-Wen Nienhuys via GitGitGadget
` (3 subsequent siblings)
6 siblings, 0 replies; 15+ messages in thread
From: Han-Wen Nienhuys via GitGitGadget @ 2023-09-20 13:02 UTC (permalink / raw)
To: git; +Cc: Han-Wen Nienhuys, Han-Wen Nienhuys, Han-Wen Nienhuys
From: Han-Wen Nienhuys <hanwen@google.com>
Take packed-refs.lock in the transaction_begin of the packed backend.
This decouples the files backend from the packed backend, allowing the
latter to be swapped out by another ref backend.
Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
---
refs.c | 5 ++-
refs/files-backend.c | 78 +++++++++++++++----------------------------
refs/packed-backend.c | 55 ++++++++++++------------------
refs/packed-backend.h | 10 ------
4 files changed, 50 insertions(+), 98 deletions(-)
diff --git a/refs.c b/refs.c
index f7ba3e56284..0611197dc6e 100644
--- a/refs.c
+++ b/refs.c
@@ -2320,10 +2320,9 @@ int ref_transaction_abort(struct ref_transaction *transaction,
int ret = 0;
switch (transaction->state) {
- case REF_TRANSACTION_OPEN:
- /* No need to abort explicitly. */
- break;
case REF_TRANSACTION_PREPARED:
+ case REF_TRANSACTION_OPEN:
+ /* an OPEN transactions may have a lock. */
ret = refs->be->transaction_abort(refs, transaction, err);
break;
case REF_TRANSACTION_CLOSED:
diff --git a/refs/files-backend.c b/refs/files-backend.c
index d83eea8b408..43c1882be3c 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -1219,10 +1219,10 @@ static int files_pack_refs(struct ref_store *ref_store,
struct ref_transaction *transaction;
transaction = ref_store_transaction_begin(refs->packed_ref_store, &err);
- if (!transaction)
+ if (!transaction) {
+ die("could not start transaction: %s", err.buf);
return -1;
-
- packed_refs_lock(refs->packed_ref_store, LOCK_DIE_ON_ERROR, &err);
+ }
iter = cache_ref_iterator_begin(get_loose_ref_cache(refs), NULL,
the_repository, 0);
@@ -1262,8 +1262,6 @@ static int files_pack_refs(struct ref_store *ref_store,
ref_transaction_free(transaction);
- packed_refs_unlock(refs->packed_ref_store);
-
prune_refs(refs, &refs_to_prune);
strbuf_release(&err);
return 0;
@@ -1280,16 +1278,10 @@ static int files_delete_refs(struct ref_store *ref_store, const char *msg,
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;
@@ -2640,7 +2632,7 @@ out:
struct files_transaction_backend_data {
struct ref_transaction *packed_transaction;
- int packed_refs_locked;
+ int packed_transaction_needed;
};
/*
@@ -2672,10 +2664,8 @@ static void files_transaction_cleanup(struct files_ref_store *refs,
strbuf_release(&err);
}
- if (backend_data->packed_refs_locked)
- packed_refs_unlock(refs->packed_ref_store);
-
free(backend_data);
+ transaction->backend_data = NULL;
}
transaction->state = REF_TRANSACTION_CLOSED;
@@ -2811,14 +2801,9 @@ static int files_transaction_prepare(struct ref_store *ref_store,
}
if (packed_transaction) {
- if (packed_refs_lock(refs->packed_ref_store, 0, err)) {
- ret = TRANSACTION_GENERIC_ERROR;
- goto cleanup;
- }
- backend_data->packed_refs_locked = 1;
-
- if (is_packed_transaction_needed(refs->packed_ref_store,
- packed_transaction)) {
+ backend_data->packed_transaction_needed = is_packed_transaction_needed(refs->packed_ref_store,
+ packed_transaction);
+ if (backend_data->packed_transaction_needed) {
ret = ref_transaction_prepare(packed_transaction, err);
/*
* A failure during the prepare step will abort
@@ -2830,22 +2815,6 @@ static int files_transaction_prepare(struct ref_store *ref_store,
ref_transaction_free(packed_transaction);
backend_data->packed_transaction = NULL;
}
- } else {
- /*
- * We can skip rewriting the `packed-refs`
- * file. But we do need to leave it locked, so
- * that somebody else doesn't pack a reference
- * that we are trying to delete.
- *
- * We need to disconnect our transaction from
- * backend_data, since the abort (whether successful or
- * not) will free it.
- */
- backend_data->packed_transaction = NULL;
- if (ref_transaction_abort(packed_transaction, err)) {
- ret = TRANSACTION_GENERIC_ERROR;
- goto cleanup;
- }
}
}
@@ -2947,13 +2916,24 @@ static int files_transaction_finish(struct ref_store *ref_store,
* First delete any packed versions of the references, while
* retaining the packed-refs lock:
*/
- if (packed_transaction) {
- ret = ref_transaction_commit(packed_transaction, err);
- ref_transaction_free(packed_transaction);
- packed_transaction = NULL;
- backend_data->packed_transaction = NULL;
- if (ret)
- goto cleanup;
+ if (backend_data->packed_transaction) {
+ if (backend_data->packed_transaction_needed) {
+ ret = ref_transaction_commit(packed_transaction, err);
+ if (ret)
+ goto cleanup;
+
+ ref_transaction_free(packed_transaction);
+ packed_transaction = NULL;
+ backend_data->packed_transaction = NULL;
+ } else {
+ ret = ref_transaction_abort(packed_transaction, err);
+ if (ret)
+ goto cleanup;
+
+ /* transaction_commit doesn't free the data, but transaction_abort does. Go figure. */
+ packed_transaction = NULL;
+ backend_data->packed_transaction = NULL;
+ }
}
/* Now delete the loose versions of the references: */
@@ -3094,16 +3074,10 @@ static int files_initial_transaction_commit(struct ref_store *ref_store,
NULL);
}
- if (packed_refs_lock(refs->packed_ref_store, 0, err)) {
- ret = TRANSACTION_GENERIC_ERROR;
- goto cleanup;
- }
-
if (initial_ref_transaction_commit(packed_transaction, err)) {
ret = TRANSACTION_GENERIC_ERROR;
}
- packed_refs_unlock(refs->packed_ref_store);
cleanup:
if (packed_transaction)
ref_transaction_free(packed_transaction);
diff --git a/refs/packed-backend.c b/refs/packed-backend.c
index 4f5b1025605..f8b27f1afe5 100644
--- a/refs/packed-backend.c
+++ b/refs/packed-backend.c
@@ -1153,7 +1153,7 @@ static int write_packed_entry(FILE *fh, const char *refname,
return 0;
}
-int packed_refs_lock(struct ref_store *ref_store, int flags, struct strbuf *err)
+static int packed_refs_lock(struct ref_store *ref_store, int flags, struct strbuf *err)
{
struct packed_ref_store *refs =
packed_downcast(ref_store, REF_STORE_WRITE | REF_STORE_MAIN,
@@ -1212,7 +1212,7 @@ int packed_refs_lock(struct ref_store *ref_store, int flags, struct strbuf *err)
return 0;
}
-void packed_refs_unlock(struct ref_store *ref_store)
+static void packed_refs_unlock(struct ref_store *ref_store)
{
struct packed_ref_store *refs = packed_downcast(
ref_store,
@@ -1224,16 +1224,6 @@ void packed_refs_unlock(struct ref_store *ref_store)
rollback_lock_file(&refs->lock);
}
-int packed_refs_is_locked(struct ref_store *ref_store)
-{
- struct packed_ref_store *refs = packed_downcast(
- ref_store,
- REF_STORE_READ | REF_STORE_WRITE,
- "packed_refs_is_locked");
-
- return is_lock_file_locked(&refs->lock);
-}
-
/*
* The packed-refs header line that we write out. Perhaps other traits
* will be added later.
@@ -1552,8 +1542,6 @@ int is_packed_transaction_needed(struct ref_store *ref_store,
struct packed_transaction_backend_data {
/* True iff the transaction owns the packed-refs lock. */
- int own_lock;
-
struct string_list updates;
};
@@ -1568,9 +1556,8 @@ static void packed_transaction_cleanup(struct packed_ref_store *refs,
if (is_tempfile_active(refs->tempfile))
delete_tempfile(&refs->tempfile);
- if (data->own_lock && is_lock_file_locked(&refs->lock)) {
+ if (is_lock_file_locked(&refs->lock)) {
packed_refs_unlock(&refs->base);
- data->own_lock = 0;
}
free(data);
@@ -1580,12 +1567,25 @@ static void packed_transaction_cleanup(struct packed_ref_store *refs,
transaction->state = REF_TRANSACTION_CLOSED;
}
-
static struct ref_transaction *packed_transaction_begin(struct ref_store *ref_store,
- struct strbuf *err) {
- struct ref_transaction *tr;
- CALLOC_ARRAY(tr, 1);
- return tr;
+ struct strbuf *err)
+{
+ struct packed_ref_store *refs = packed_downcast(
+ ref_store,
+ REF_STORE_READ | REF_STORE_WRITE | REF_STORE_ODB,
+ "ref_transaction_begin");
+ struct packed_transaction_backend_data *data;
+ struct ref_transaction *transaction;
+
+ if (!is_lock_file_locked(&refs->lock)) {
+ if (packed_refs_lock(ref_store, 0, err))
+ return NULL;
+ }
+ CALLOC_ARRAY(transaction, 1);
+ CALLOC_ARRAY(data, 1);
+ string_list_init_nodup(&data->updates);
+ transaction->backend_data = data;
+ return transaction;
}
static int packed_transaction_prepare(struct ref_store *ref_store,
@@ -1596,7 +1596,7 @@ static int packed_transaction_prepare(struct ref_store *ref_store,
ref_store,
REF_STORE_READ | REF_STORE_WRITE | REF_STORE_ODB,
"ref_transaction_prepare");
- struct packed_transaction_backend_data *data;
+ struct packed_transaction_backend_data *data = transaction->backend_data;
size_t i;
int ret = TRANSACTION_GENERIC_ERROR;
@@ -1609,11 +1609,6 @@ static int packed_transaction_prepare(struct ref_store *ref_store,
* do so itself.
*/
- CALLOC_ARRAY(data, 1);
- string_list_init_nodup(&data->updates);
-
- transaction->backend_data = data;
-
/*
* Stick the updates in a string list by refname so that we
* can sort them:
@@ -1631,12 +1626,6 @@ static int packed_transaction_prepare(struct ref_store *ref_store,
if (ref_update_reject_duplicates(&data->updates, err))
goto failure;
- if (!is_lock_file_locked(&refs->lock)) {
- if (packed_refs_lock(ref_store, 0, err))
- goto failure;
- data->own_lock = 1;
- }
-
if (write_with_updates(refs, &data->updates, err))
goto failure;
diff --git a/refs/packed-backend.h b/refs/packed-backend.h
index 9dd8a344c34..ade3c8a5ac4 100644
--- a/refs/packed-backend.h
+++ b/refs/packed-backend.h
@@ -17,16 +17,6 @@ struct ref_store *packed_ref_store_create(struct repository *repo,
const char *gitdir,
unsigned int store_flags);
-/*
- * Lock the packed-refs file for writing. Flags is passed to
- * hold_lock_file_for_update(). Return 0 on success. On errors, write
- * an error message to `err` and return a nonzero value.
- */
-int packed_refs_lock(struct ref_store *ref_store, int flags, struct strbuf *err);
-
-void packed_refs_unlock(struct ref_store *ref_store);
-int packed_refs_is_locked(struct ref_store *ref_store);
-
/*
* Return true if `transaction` really needs to be carried out against
* the specified packed_ref_store, or false if it can be skipped
--
gitgitgadget
^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH v2 4/6] refs: move is_packed_transaction_needed out of packed-backend.c
2023-09-20 13:02 ` [PATCH v2 0/6] RFC: simple " Han-Wen Nienhuys via GitGitGadget
` (2 preceding siblings ...)
2023-09-20 13:02 ` [PATCH v2 3/6] refs: push lock management into packed backend Han-Wen Nienhuys via GitGitGadget
@ 2023-09-20 13:02 ` Han-Wen Nienhuys via GitGitGadget
2023-09-20 13:02 ` [PATCH v2 5/6] refs: alternate reftable ref backend implementation Han-Wen Nienhuys via GitGitGadget
` (2 subsequent siblings)
6 siblings, 0 replies; 15+ messages in thread
From: Han-Wen Nienhuys via GitGitGadget @ 2023-09-20 13:02 UTC (permalink / raw)
To: git; +Cc: Han-Wen Nienhuys, Han-Wen Nienhuys, Han-Wen Nienhuys
From: Han-Wen Nienhuys <hanwen@google.com>
It is no longer specific to the packed backend.
Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
---
refs/files-backend.c | 94 ++++++++++++++++++++++++++++++++++++++++++
refs/packed-backend.c | 95 -------------------------------------------
refs/packed-backend.h | 9 ----
3 files changed, 94 insertions(+), 104 deletions(-)
diff --git a/refs/files-backend.c b/refs/files-backend.c
index 43c1882be3c..5d288bf38bb 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -2630,6 +2630,100 @@ out:
return ret;
}
+/*
+ * Return true if `transaction` really needs to be carried out against
+ * the specified packed_ref_store, or false if it can be skipped
+ * (i.e., because it is an obvious NOOP). `ref_store` must be locked
+ * before calling this function.
+ */
+static int is_packed_transaction_needed(struct ref_store *ref_store,
+ struct ref_transaction *transaction)
+{
+ struct strbuf referent = STRBUF_INIT;
+ size_t i;
+ int ret;
+
+ /*
+ * We're only going to bother returning false for the common,
+ * trivial case that references are only being deleted, their
+ * old values are not being checked, and the old `packed-refs`
+ * file doesn't contain any of those reference(s). This gives
+ * false positives for some other cases that could
+ * theoretically be optimized away:
+ *
+ * 1. It could be that the old value is being verified without
+ * setting a new value. In this case, we could verify the
+ * old value here and skip the update if it agrees. If it
+ * disagrees, we could either let the update go through
+ * (the actual commit would re-detect and report the
+ * problem), or come up with a way of reporting such an
+ * error to *our* caller.
+ *
+ * 2. It could be that a new value is being set, but that it
+ * is identical to the current packed value of the
+ * reference.
+ *
+ * Neither of these cases will come up in the current code,
+ * because the only caller of this function passes to it a
+ * transaction that only includes `delete` updates with no
+ * `old_id`. Even if that ever changes, false positives only
+ * cause an optimization to be missed; they do not affect
+ * correctness.
+ */
+
+ /*
+ * Start with the cheap checks that don't require old
+ * reference values to be read:
+ */
+ for (i = 0; i < transaction->nr; i++) {
+ struct ref_update *update = transaction->updates[i];
+
+ if (update->flags & REF_HAVE_OLD)
+ /* Have to check the old value -> needed. */
+ return 1;
+
+ if ((update->flags & REF_HAVE_NEW) && !is_null_oid(&update->new_oid))
+ /* Have to set a new value -> needed. */
+ return 1;
+ }
+
+ /*
+ * The transaction isn't checking any old values nor is it
+ * setting any nonzero new values, so it still might be able
+ * to be skipped. Now do the more expensive check: the update
+ * is needed if any of the updates is a delete, and the old
+ * `packed-refs` file contains a value for that reference.
+ */
+ ret = 0;
+ for (i = 0; i < transaction->nr; i++) {
+ struct ref_update *update = transaction->updates[i];
+ int failure_errno;
+ unsigned int type;
+ struct object_id oid;
+
+ if (!(update->flags & REF_HAVE_NEW))
+ /*
+ * This reference isn't being deleted -> not
+ * needed.
+ */
+ continue;
+
+ if (!refs_read_raw_ref(ref_store, update->refname, &oid,
+ &referent, &type, &failure_errno) ||
+ failure_errno != ENOENT) {
+ /*
+ * We have to actually delete that reference
+ * -> this transaction is needed.
+ */
+ ret = 1;
+ break;
+ }
+ }
+
+ strbuf_release(&referent);
+ return ret;
+}
+
struct files_transaction_backend_data {
struct ref_transaction *packed_transaction;
int packed_transaction_needed;
diff --git a/refs/packed-backend.c b/refs/packed-backend.c
index f8b27f1afe5..2017d117c13 100644
--- a/refs/packed-backend.c
+++ b/refs/packed-backend.c
@@ -1445,101 +1445,6 @@ error:
return -1;
}
-int is_packed_transaction_needed(struct ref_store *ref_store,
- struct ref_transaction *transaction)
-{
- struct packed_ref_store *refs = packed_downcast(
- ref_store,
- REF_STORE_READ,
- "is_packed_transaction_needed");
- struct strbuf referent = STRBUF_INIT;
- size_t i;
- int ret;
-
- if (!is_lock_file_locked(&refs->lock))
- BUG("is_packed_transaction_needed() called while unlocked");
-
- /*
- * We're only going to bother returning false for the common,
- * trivial case that references are only being deleted, their
- * old values are not being checked, and the old `packed-refs`
- * file doesn't contain any of those reference(s). This gives
- * false positives for some other cases that could
- * theoretically be optimized away:
- *
- * 1. It could be that the old value is being verified without
- * setting a new value. In this case, we could verify the
- * old value here and skip the update if it agrees. If it
- * disagrees, we could either let the update go through
- * (the actual commit would re-detect and report the
- * problem), or come up with a way of reporting such an
- * error to *our* caller.
- *
- * 2. It could be that a new value is being set, but that it
- * is identical to the current packed value of the
- * reference.
- *
- * Neither of these cases will come up in the current code,
- * because the only caller of this function passes to it a
- * transaction that only includes `delete` updates with no
- * `old_id`. Even if that ever changes, false positives only
- * cause an optimization to be missed; they do not affect
- * correctness.
- */
-
- /*
- * Start with the cheap checks that don't require old
- * reference values to be read:
- */
- for (i = 0; i < transaction->nr; i++) {
- struct ref_update *update = transaction->updates[i];
-
- if (update->flags & REF_HAVE_OLD)
- /* Have to check the old value -> needed. */
- return 1;
-
- if ((update->flags & REF_HAVE_NEW) && !is_null_oid(&update->new_oid))
- /* Have to set a new value -> needed. */
- return 1;
- }
-
- /*
- * The transaction isn't checking any old values nor is it
- * setting any nonzero new values, so it still might be able
- * to be skipped. Now do the more expensive check: the update
- * is needed if any of the updates is a delete, and the old
- * `packed-refs` file contains a value for that reference.
- */
- ret = 0;
- for (i = 0; i < transaction->nr; i++) {
- struct ref_update *update = transaction->updates[i];
- int failure_errno;
- unsigned int type;
- struct object_id oid;
-
- if (!(update->flags & REF_HAVE_NEW))
- /*
- * This reference isn't being deleted -> not
- * needed.
- */
- continue;
-
- if (!refs_read_raw_ref(ref_store, update->refname, &oid,
- &referent, &type, &failure_errno) ||
- failure_errno != ENOENT) {
- /*
- * We have to actually delete that reference
- * -> this transaction is needed.
- */
- ret = 1;
- break;
- }
- }
-
- strbuf_release(&referent);
- return ret;
-}
-
struct packed_transaction_backend_data {
/* True iff the transaction owns the packed-refs lock. */
struct string_list updates;
diff --git a/refs/packed-backend.h b/refs/packed-backend.h
index ade3c8a5ac4..51a3b6a332a 100644
--- a/refs/packed-backend.h
+++ b/refs/packed-backend.h
@@ -17,13 +17,4 @@ struct ref_store *packed_ref_store_create(struct repository *repo,
const char *gitdir,
unsigned int store_flags);
-/*
- * Return true if `transaction` really needs to be carried out against
- * the specified packed_ref_store, or false if it can be skipped
- * (i.e., because it is an obvious NOOP). `ref_store` must be locked
- * before calling this function.
- */
-int is_packed_transaction_needed(struct ref_store *ref_store,
- struct ref_transaction *transaction);
-
#endif /* REFS_PACKED_BACKEND_H */
--
gitgitgadget
^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH v2 5/6] refs: alternate reftable ref backend implementation
2023-09-20 13:02 ` [PATCH v2 0/6] RFC: simple " Han-Wen Nienhuys via GitGitGadget
` (3 preceding siblings ...)
2023-09-20 13:02 ` [PATCH v2 4/6] refs: move is_packed_transaction_needed out of packed-backend.c Han-Wen Nienhuys via GitGitGadget
@ 2023-09-20 13:02 ` Han-Wen Nienhuys via GitGitGadget
2023-09-20 13:02 ` [PATCH v2 6/6] refs: always try to do packed transactions for reftable Han-Wen Nienhuys via GitGitGadget
2023-09-21 10:01 ` [PATCH v2 0/6] RFC: simple reftable backend Patrick Steinhardt
6 siblings, 0 replies; 15+ messages in thread
From: Han-Wen Nienhuys via GitGitGadget @ 2023-09-20 13:02 UTC (permalink / raw)
To: git; +Cc: Han-Wen Nienhuys, Han-Wen Nienhuys, Han-Wen Nienhuys
From: Han-Wen Nienhuys <hanwen@google.com>
This introduces the reftable backend as an alternative to the packed
backend.
This is an alternative to the approach which was explored in
https://github.com/git/git/pull/1215/. This alternative is simpler,
because we now longer have to worry about:
- pseudorefs and the HEAD ref
- worktrees
- commands that blur together files and references (cherry-pick, rebase)
This deviates from the spec that in
Documentation/technical/reftable.txt. It might be possible to update the
code such that all writes by default go to reftable directly. Then the
result would be compatible with an implementation that writes only
reftable (the reftable lock would still prevent races), but something
must be done about the HEAD ref (which JGit keeps in reftable too.)
Alternatively, JGit could be adapted to follow this implementation:
despite the code being there for 4 years now, I haven't heard of anyone
using it in production (exactly because CGit does not support it).
For this incremental path, the reftable format is arguably more
complex than necessary, as
- packed-refs doesn't support symrefs
- reflogs aren't moved into reftable
on the other hand, the code is already there, and it's well-structured
and well-tested.
refs/reftable-backend.c was created by cannibalizing the first version
of reftable support (github PR 1215 as mentioned above). It supports
reflogs and symrefs, even though those features are never exercised.
This implementation is a prototype, for the following reasons:
- no considerations of backward compatibility and configuring an
extension
- no support for converting between packed-refs and reftable
- no documentation
- test failures when setting GIT_TEST_REFTABLE=1.
Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
---
Makefile | 1 +
config.mak.uname | 2 +-
contrib/workdir/git-new-workdir | 2 +-
refs/files-backend.c | 18 +-
refs/refs-internal.h | 1 +
refs/reftable-backend.c | 1658 +++++++++++++++++++++++++++++++
refs/reftable-backend.h | 8 +
7 files changed, 1686 insertions(+), 4 deletions(-)
create mode 100644 refs/reftable-backend.c
create mode 100644 refs/reftable-backend.h
diff --git a/Makefile b/Makefile
index 57763093653..272d3f7f1e9 100644
--- a/Makefile
+++ b/Makefile
@@ -1118,6 +1118,7 @@ LIB_OBJS += reflog.o
LIB_OBJS += refs.o
LIB_OBJS += refs/debug.o
LIB_OBJS += refs/files-backend.o
+LIB_OBJS += refs/reftable-backend.o
LIB_OBJS += refs/iterator.o
LIB_OBJS += refs/packed-backend.o
LIB_OBJS += refs/ref-cache.o
diff --git a/config.mak.uname b/config.mak.uname
index 3bb03f423a0..843829c02fd 100644
--- a/config.mak.uname
+++ b/config.mak.uname
@@ -743,7 +743,7 @@ vcxproj:
# Make .vcxproj files and add them
perl contrib/buildsystems/generate -g Vcxproj
- git add -f git.sln {*,*/lib,t/helper/*}/*.vcxproj
+ git add -f git.sln {*,*/lib,*/libreftable,t/helper/*}/*.vcxproj
# Generate the LinkOrCopyBuiltins.targets and LinkOrCopyRemoteHttp.targets file
(echo '<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">' && \
diff --git a/contrib/workdir/git-new-workdir b/contrib/workdir/git-new-workdir
index 888c34a5215..989197aace0 100755
--- a/contrib/workdir/git-new-workdir
+++ b/contrib/workdir/git-new-workdir
@@ -79,7 +79,7 @@ trap cleanup $siglist
# create the links to the original repo. explicitly exclude index, HEAD and
# logs/HEAD from the list since they are purely related to the current working
# directory, and should not be shared.
-for x in config refs logs/refs objects info hooks packed-refs remotes rr-cache svn
+for x in config refs logs/refs objects info hooks packed-refs remotes rr-cache svn reftable
do
# create a containing directory if needed
case $x in
diff --git a/refs/files-backend.c b/refs/files-backend.c
index 5d288bf38bb..2cd596bbeba 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -1,4 +1,5 @@
#include "../git-compat-util.h"
+#include "../abspath.h"
#include "../config.h"
#include "../copy.h"
#include "../environment.h"
@@ -9,6 +10,7 @@
#include "refs-internal.h"
#include "ref-cache.h"
#include "packed-backend.h"
+#include "reftable-backend.h"
#include "../ident.h"
#include "../iterator.h"
#include "../dir-iterator.h"
@@ -98,13 +100,25 @@ static struct ref_store *files_ref_store_create(struct repository *repo,
struct files_ref_store *refs = xcalloc(1, sizeof(*refs));
struct ref_store *ref_store = (struct ref_store *)refs;
struct strbuf sb = STRBUF_INIT;
+ int has_reftable, has_packed;
base_ref_store_init(ref_store, repo, gitdir, &refs_be_files);
refs->store_flags = flags;
get_common_dir_noenv(&sb, gitdir);
refs->gitcommondir = strbuf_detach(&sb, NULL);
- refs->packed_ref_store =
- packed_ref_store_create(repo, refs->gitcommondir, flags);
+
+ strbuf_addf(&sb, "%s/reftable", refs->gitcommondir);
+ has_reftable = is_directory(sb.buf);
+ strbuf_reset(&sb);
+ strbuf_addf(&sb, "%s/packed-refs", refs->gitcommondir);
+ has_packed = file_exists(sb.buf);
+
+ if (!has_packed && !has_reftable)
+ has_reftable = git_env_bool("GIT_TEST_REFTABLE", 0);
+
+ refs->packed_ref_store = has_reftable
+ ? git_reftable_ref_store_create(repo, refs->gitcommondir, flags)
+ : packed_ref_store_create(repo, refs->gitcommondir, flags);
chdir_notify_reparent("files-backend $GIT_DIR", &refs->base.gitdir);
chdir_notify_reparent("files-backend $GIT_COMMONDIR",
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index 0a15e8a2ac8..13bd9c79f3c 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -699,6 +699,7 @@ 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;
/*
diff --git a/refs/reftable-backend.c b/refs/reftable-backend.c
new file mode 100644
index 00000000000..16064fff198
--- /dev/null
+++ b/refs/reftable-backend.c
@@ -0,0 +1,1658 @@
+#include "../git-compat-util.h"
+#include "../abspath.h"
+#include "../chdir-notify.h"
+#include "../config.h"
+#include "../environment.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-blocksource.h"
+#include "../reftable/reftable-reader.h"
+#include "../reftable/reftable-iterator.h"
+#include "../reftable/reftable-merged.h"
+#include "../reftable/reftable-generic.h"
+#include "../worktree.h"
+#include "refs-internal.h"
+#include "reftable-backend.h"
+#include "../repository.h"
+
+extern struct ref_storage_be refs_be_reftable;
+
+struct git_reftable_ref_store {
+ struct ref_store base;
+ unsigned int store_flags;
+
+ int err;
+ char *repo_dir;
+ char *reftable_dir;
+
+ struct reftable_stack *main_stack;
+
+ struct reftable_write_options write_options;
+};
+
+static struct reftable_stack *stack_for(struct git_reftable_ref_store *store,
+ const char *refname)
+{
+ return store->main_stack;
+}
+
+static int should_log(const char *refname)
+{
+ return log_all_ref_updates != LOG_REFS_NONE &&
+ (log_all_ref_updates == LOG_REFS_ALWAYS ||
+ log_all_ref_updates == LOG_REFS_UNSET ||
+ should_autocreate_reflog(refname));
+}
+
+static const char *bare_ref_name(const char *ref)
+{
+ const char *stripped;
+ parse_worktree_ref(ref, NULL, NULL, &stripped);
+ return stripped;
+}
+
+static int git_reftable_read_raw_ref(struct ref_store *ref_store,
+ const char *refname, struct object_id *oid,
+ struct strbuf *referent,
+ unsigned int *type, int *failure_errno);
+
+static void clear_reftable_log_record(struct reftable_log_record *log)
+{
+ switch (log->value_type) {
+ case REFTABLE_LOG_UPDATE:
+ /* when we write log records, the hashes are owned by a struct
+ * oid */
+ log->value.update.old_hash = NULL;
+ log->value.update.new_hash = NULL;
+ break;
+ case REFTABLE_LOG_DELETION:
+ break;
+ }
+ reftable_log_record_release(log);
+}
+
+static void fill_reftable_log_record(struct reftable_log_record *log)
+{
+ const char *info = git_committer_info(0);
+ struct ident_split split = { NULL };
+ int result = split_ident_line(&split, info, strlen(info));
+ int sign = 1;
+ assert(0 == result);
+
+ 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);
+ if (*split.tz_begin == '-') {
+ sign = -1;
+ split.tz_begin++;
+ }
+ if (*split.tz_begin == '+') {
+ sign = 1;
+ split.tz_begin++;
+ }
+
+ log->value.update.tz_offset = sign * atoi(split.tz_begin);
+}
+
+struct ref_store *git_reftable_ref_store_create(struct repository *repo,
+ const char *gitdir,
+ unsigned int store_flags)
+{
+ struct git_reftable_ref_store *refs = xcalloc(1, sizeof(*refs));
+ struct ref_store *ref_store = (struct ref_store *)refs;
+ struct strbuf sb = STRBUF_INIT;
+ int shared = get_shared_repository();
+ if (shared < 0)
+ shared = -shared;
+
+ refs->write_options.block_size = 4096;
+ refs->write_options.hash_id = the_hash_algo->format_id;
+ if (shared && (shared & 0600))
+ refs->write_options.default_permissions = shared;
+
+ /* XXX should this use `path` or `gitdir.buf` ? */
+ base_ref_store_init(ref_store, repo, gitdir, &refs_be_reftable);
+ refs->store_flags = store_flags;
+ strbuf_addf(&sb, "%s/reftable", gitdir);
+ refs->reftable_dir = xstrdup(sb.buf);
+ safe_create_dir(refs->reftable_dir, 1);
+
+ refs->base.repo = repo;
+ strbuf_reset(&sb);
+
+ refs->err = reftable_new_stack(&refs->main_stack, refs->reftable_dir,
+ refs->write_options);
+ assert(refs->err != REFTABLE_API_ERROR);
+
+ strbuf_release(&sb);
+
+ /* TODO something with chdir_notify_reparent() ? */
+
+ return ref_store;
+}
+
+static int git_reftable_init_db(struct ref_store *ref_store, struct strbuf *err)
+{
+ struct git_reftable_ref_store *refs =
+ (struct git_reftable_ref_store *)ref_store;
+ safe_create_dir(refs->reftable_dir, 1);
+ return 0;
+}
+
+struct git_reftable_iterator {
+ struct ref_iterator base;
+ struct reftable_iterator iter;
+ struct reftable_ref_record ref;
+ struct object_id oid;
+ struct ref_store *ref_store;
+
+ unsigned int flags;
+ int err;
+ const char *prefix;
+};
+
+static int reftable_ref_iterator_advance(struct ref_iterator *ref_iterator)
+{
+ struct git_reftable_iterator *ri =
+ (struct git_reftable_iterator *)ref_iterator;
+ struct git_reftable_ref_store *refs =
+ (struct git_reftable_ref_store *)ri->ref_store;
+
+ while (ri->err == 0) {
+ int signed_flags = 0;
+ ri->err = reftable_iterator_next_ref(&ri->iter, &ri->ref);
+ if (ri->err) {
+ break;
+ }
+
+ ri->base.flags = 0;
+
+ if (!strcmp(ri->ref.refname, "HEAD")) {
+ /*
+ HEAD should not be produced by default.Other
+ pseudorefs (FETCH_HEAD etc.) shouldn't be
+ stored in reftables at all.
+ */
+ continue;
+ }
+ ri->base.refname = ri->ref.refname;
+ if (ri->prefix &&
+ strncmp(ri->prefix, ri->ref.refname, strlen(ri->prefix))) {
+ ri->err = 1;
+ break;
+ }
+ if (ri->flags & DO_FOR_EACH_PER_WORKTREE_ONLY &&
+ parse_worktree_ref(ri->base.refname, NULL, NULL, NULL) !=
+ REF_WORKTREE_CURRENT)
+ continue;
+
+ if (ri->flags & DO_FOR_EACH_INCLUDE_BROKEN &&
+ check_refname_format(ri->base.refname,
+ REFNAME_ALLOW_ONELEVEL)) {
+ /* This is odd, as REF_BAD_NAME and REF_ISBROKEN are
+ orthogonal, but it's what the spec says and the
+ files-backend does. */
+ ri->base.flags |= REF_BAD_NAME | REF_ISBROKEN;
+ break;
+ }
+
+ switch (ri->ref.value_type) {
+ case REFTABLE_REF_VAL1:
+ oidread(&ri->oid, ri->ref.value.val1);
+ break;
+ case REFTABLE_REF_VAL2:
+ oidread(&ri->oid, ri->ref.value.val2.value);
+ break;
+ case REFTABLE_REF_SYMREF:
+ ri->base.flags = REF_ISSYMREF;
+ break;
+ default:
+ abort();
+ }
+
+ ri->base.oid = &ri->oid;
+ if (!(ri->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&
+ !ref_resolves_to_object(ri->base.refname, refs->base.repo,
+ ri->base.oid, ri->base.flags)) {
+ continue;
+ }
+
+ /* Arguably, resolving recursively following symlinks should be
+ * lifted to refs.c because it is shared between reftable and
+ * the files backend, but it's here now.
+ */
+ if (!refs_resolve_ref_unsafe(ri->ref_store, ri->ref.refname,
+ RESOLVE_REF_READING, &ri->oid,
+ &signed_flags)) {
+ ri->base.flags = signed_flags;
+ if (ri->ref.value_type == REFTABLE_REF_SYMREF &&
+ ri->flags & DO_FOR_EACH_OMIT_DANGLING_SYMREFS)
+ continue;
+
+ if (ri->ref.value_type == REFTABLE_REF_SYMREF &&
+ !(ri->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&
+ (ri->base.flags & REF_ISBROKEN)) {
+ continue;
+ }
+
+ if (is_null_oid(&ri->oid)) {
+ oidclr(&ri->oid);
+ ri->base.flags |= REF_ISBROKEN;
+ }
+ }
+ break;
+ }
+
+ if (ri->err > 0) {
+ return ITER_DONE;
+ }
+ if (ri->err < 0) {
+ return ITER_ERROR;
+ }
+
+ return ITER_OK;
+}
+
+static int reftable_ref_iterator_peel(struct ref_iterator *ref_iterator,
+ struct object_id *peeled)
+{
+ struct git_reftable_iterator *ri =
+ (struct git_reftable_iterator *)ref_iterator;
+ if (ri->ref.value_type == REFTABLE_REF_VAL2) {
+ oidread(peeled, ri->ref.value.val2.target_value);
+ return 0;
+ }
+
+ return -1;
+}
+
+static int reftable_ref_iterator_abort(struct ref_iterator *ref_iterator)
+{
+ struct git_reftable_iterator *ri =
+ (struct git_reftable_iterator *)ref_iterator;
+ reftable_ref_record_release(&ri->ref);
+ reftable_iterator_destroy(&ri->iter);
+ return 0;
+}
+
+static struct ref_iterator_vtable reftable_ref_iterator_vtable = {
+ reftable_ref_iterator_advance, reftable_ref_iterator_peel,
+ reftable_ref_iterator_abort
+};
+
+static struct ref_iterator *
+git_reftable_ref_iterator_begin(struct ref_store *ref_store, const char *prefix,
+ const char **exclude_patterns_TODO,
+ unsigned int flags)
+{
+ struct git_reftable_ref_store *refs =
+ (struct git_reftable_ref_store *)ref_store;
+ struct git_reftable_iterator *ri = xcalloc(1, sizeof(*ri));
+
+ if (refs->err < 0) {
+ ri->err = refs->err;
+ } else {
+ struct reftable_merged_table *mt =
+ reftable_stack_merged_table(refs->main_stack);
+ ri->err = reftable_merged_table_seek_ref(mt, &ri->iter, prefix);
+ }
+
+ base_ref_iterator_init(&ri->base, &reftable_ref_iterator_vtable, 1);
+ ri->prefix = prefix;
+ ri->base.oid = &ri->oid;
+ ri->flags = flags;
+ ri->ref_store = ref_store;
+ return &ri->base;
+}
+
+static struct ref_transaction *git_reftable_transaction_begin(struct ref_store *ref_store,
+ struct strbuf *errbuf)
+{
+ struct git_reftable_ref_store *refs =
+ (struct git_reftable_ref_store *)ref_store;
+ struct reftable_addition *add = NULL;
+ struct ref_transaction *transaction = NULL;
+ struct reftable_stack *stack = refs->main_stack;
+
+ int err = refs->err;
+ if (err < 0) {
+ goto done;
+ }
+
+ err = reftable_stack_reload(stack);
+ if (err) {
+ goto done;
+ }
+
+ err = reftable_stack_new_addition(&add, stack);
+ if (err) {
+ strbuf_addf(errbuf, "reftable: transaction begin: %s",
+ reftable_error_str(err));
+ goto done;
+ }
+
+ CALLOC_ARRAY(transaction, 1);
+ transaction->backend_data = add;
+done:
+ return transaction;
+}
+
+static int git_reftable_transaction_prepare(struct ref_store *ref_store,
+ struct ref_transaction *transaction,
+ struct strbuf *errbuf)
+{
+ transaction->state = REF_TRANSACTION_PREPARED;
+ return 0;
+}
+
+static int git_reftable_transaction_abort(struct ref_store *ref_store,
+ struct ref_transaction *transaction,
+ struct strbuf *err)
+{
+ struct reftable_addition *add =
+ (struct reftable_addition *)transaction->backend_data;
+ reftable_addition_destroy(add);
+ transaction->backend_data = NULL;
+
+ /* XXX. Shouldn't this be handled generically in refs.c? */
+ transaction->state = REF_TRANSACTION_CLOSED;
+ return 0;
+}
+
+static int reftable_check_old_oid(struct ref_store *refs, const char *refname,
+ struct object_id *want_oid)
+{
+ struct object_id out_oid;
+ int out_flags = 0;
+ const char *resolved = refs_resolve_ref_unsafe(
+ refs, refname, RESOLVE_REF_READING, &out_oid, &out_flags);
+ if (is_null_oid(want_oid) != !resolved) {
+ return REFTABLE_LOCK_ERROR;
+ }
+
+ if (resolved && !oideq(&out_oid, want_oid)) {
+ return REFTABLE_LOCK_ERROR;
+ }
+
+ return 0;
+}
+
+static int ref_update_cmp(const void *a, const void *b)
+{
+ return strcmp((*(struct ref_update **)a)->refname,
+ (*(struct ref_update **)b)->refname);
+}
+
+static int write_transaction_table(struct reftable_writer *writer, void *arg)
+{
+ struct ref_transaction *transaction = (struct ref_transaction *)arg;
+ struct git_reftable_ref_store *refs =
+ (struct git_reftable_ref_store *)transaction->ref_store;
+ struct reftable_stack *stack =
+ stack_for(refs, transaction->updates[0]->refname);
+ uint64_t ts = reftable_stack_next_update_index(stack);
+ int err = 0;
+ int i = 0;
+ int log_count = 0;
+ struct reftable_log_record *logs =
+ calloc(transaction->nr, sizeof(*logs));
+ struct ref_update **sorted =
+ malloc(transaction->nr * sizeof(struct ref_update *));
+ struct reftable_merged_table *mt = reftable_stack_merged_table(stack);
+ struct reftable_table tab = { NULL };
+ struct reftable_ref_record ref = { NULL };
+ reftable_table_from_merged_table(&tab, mt);
+ COPY_ARRAY(sorted, transaction->updates, transaction->nr);
+ QSORT(sorted, transaction->nr, ref_update_cmp);
+ reftable_writer_set_limits(writer, ts, ts);
+
+ for (i = 0; i < transaction->nr; i++) {
+ struct ref_update *u = sorted[i];
+ struct reftable_log_record *log = &logs[log_count];
+ struct object_id old_id = *null_oid();
+
+ log->value.update.new_hash = NULL;
+ log->value.update.old_hash = NULL;
+ if ((u->flags & REF_FORCE_CREATE_REFLOG) ||
+ should_log(u->refname))
+ log_count++;
+ fill_reftable_log_record(log);
+
+ log->update_index = ts;
+ log->value_type = REFTABLE_LOG_UPDATE;
+ log->refname = xstrdup(u->refname);
+ log->value.update.new_hash = u->new_oid.hash;
+ log->value.update.message =
+ xstrndup(u->msg, refs->write_options.block_size / 2);
+
+ err = reftable_table_read_ref(&tab, u->refname, &ref);
+ if (err < 0)
+ goto done;
+ else if (err > 0) {
+ err = 0;
+ }
+
+ /* XXX if this is a symref (say, HEAD), should we deref the
+ * symref and check the update.old_hash against the referent? */
+ if (ref.value_type == REFTABLE_REF_VAL2 ||
+ ref.value_type == REFTABLE_REF_VAL1)
+ oidread(&old_id, ref.value.val1);
+
+ /* XXX fold together with the old_id check below? */
+ log->value.update.old_hash = old_id.hash;
+ if (u->flags & REF_LOG_ONLY) {
+ continue;
+ }
+
+ if (u->flags & REF_HAVE_NEW) {
+ struct reftable_ref_record ref = { NULL };
+ struct object_id peeled;
+
+ int peel_error = peel_object(&u->new_oid, &peeled);
+ ref.refname = (char *)u->refname;
+ ref.update_index = ts;
+
+ if (!peel_error) {
+ ref.value_type = REFTABLE_REF_VAL2;
+ ref.value.val2.target_value = peeled.hash;
+ ref.value.val2.value = u->new_oid.hash;
+ } else if (!is_null_oid(&u->new_oid)) {
+ ref.value_type = REFTABLE_REF_VAL1;
+ ref.value.val1 = u->new_oid.hash;
+ }
+
+ err = reftable_writer_add_ref(writer, &ref);
+ if (err < 0) {
+ goto done;
+ }
+ }
+ }
+
+ for (i = 0; i < log_count; i++) {
+ err = reftable_writer_add_log(writer, &logs[i]);
+ logs[i].value.update.new_hash = NULL;
+ logs[i].value.update.old_hash = NULL;
+ clear_reftable_log_record(&logs[i]);
+ if (err < 0) {
+ goto done;
+ }
+ }
+
+done:
+ assert(err != REFTABLE_API_ERROR);
+ reftable_ref_record_release(&ref);
+ free(logs);
+ free(sorted);
+ return err;
+}
+
+static int git_reftable_transaction_finish(struct ref_store *ref_store,
+ struct ref_transaction *transaction,
+ struct strbuf *errmsg)
+{
+ struct git_reftable_ref_store *refs =
+ (struct git_reftable_ref_store *)transaction->ref_store;
+ struct reftable_addition *add =
+ (struct reftable_addition *)transaction->backend_data;
+ int err = 0;
+ int i;
+
+ for (i = 0; i < transaction->nr; i++) {
+ struct ref_update *u = transaction->updates[i];
+ if (u->flags & REF_HAVE_OLD) {
+ err = reftable_check_old_oid(transaction->ref_store,
+ u->refname, &u->old_oid);
+ if (err < 0) {
+ goto done;
+ }
+ }
+ }
+ if (transaction->nr) {
+ err = reftable_addition_add(add, &write_transaction_table,
+ transaction);
+ if (err < 0) {
+ goto done;
+ }
+ }
+
+ err = reftable_addition_commit(add);
+
+ if (!err)
+ err = reftable_stack_auto_compact(refs->main_stack);
+done:
+ assert(err != REFTABLE_API_ERROR);
+ reftable_addition_destroy(add);
+ transaction->state = REF_TRANSACTION_CLOSED;
+ transaction->backend_data = NULL;
+ if (err) {
+ strbuf_addf(errmsg, "reftable: transaction failure: %s",
+ reftable_error_str(err));
+ return -1;
+ }
+ return err;
+}
+
+static int
+git_reftable_transaction_initial_commit(struct ref_store *ref_store,
+ struct ref_transaction *transaction,
+ struct strbuf *errmsg)
+{
+ int err = git_reftable_transaction_prepare(ref_store, transaction,
+ errmsg);
+ if (err)
+ return err;
+
+ return git_reftable_transaction_finish(ref_store, transaction, errmsg);
+}
+
+struct write_delete_refs_arg {
+ struct git_reftable_ref_store *refs;
+ struct reftable_stack *stack;
+ struct string_list *refnames;
+ const char *logmsg;
+ unsigned int flags;
+};
+
+static int write_delete_refs_table(struct reftable_writer *writer, void *argv)
+{
+ struct write_delete_refs_arg *arg =
+ (struct write_delete_refs_arg *)argv;
+ uint64_t ts = reftable_stack_next_update_index(arg->stack);
+ int err = 0;
+ int i = 0;
+
+ reftable_writer_set_limits(writer, ts, ts);
+ for (i = 0; i < arg->refnames->nr; i++) {
+ struct reftable_ref_record ref = {
+ .refname = (char *)arg->refnames->items[i].string,
+ .value_type = REFTABLE_REF_DELETION,
+ .update_index = ts,
+ };
+ err = reftable_writer_add_ref(writer, &ref);
+ if (err < 0) {
+ return err;
+ }
+ }
+
+ for (i = 0; i < arg->refnames->nr; i++) {
+ struct reftable_log_record log = {
+ .update_index = ts,
+ };
+ struct reftable_ref_record current = { NULL };
+ fill_reftable_log_record(&log);
+ log.update_index = ts;
+ log.refname = xstrdup(arg->refnames->items[i].string);
+ if (!should_log(log.refname)) {
+ continue;
+ }
+ log.value.update.message = xstrndup(
+ arg->logmsg, arg->refs->write_options.block_size / 2);
+ log.value.update.new_hash = NULL;
+ log.value.update.old_hash = NULL;
+ if (reftable_stack_read_ref(arg->stack, log.refname,
+ ¤t) == 0) {
+ log.value.update.old_hash =
+ reftable_ref_record_val1(¤t);
+ }
+ err = reftable_writer_add_log(writer, &log);
+ log.value.update.old_hash = NULL;
+ reftable_ref_record_release(¤t);
+
+ clear_reftable_log_record(&log);
+ if (err < 0) {
+ return err;
+ }
+ }
+ return 0;
+}
+
+static int git_reftable_delete_refs(struct ref_store *ref_store,
+ const char *msg,
+ struct string_list *refnames,
+ unsigned int flags)
+{
+ struct git_reftable_ref_store *refs =
+ (struct git_reftable_ref_store *)ref_store;
+ struct reftable_stack *stack = stack_for(
+ refs, refnames->nr ? refnames->items[0].string : NULL);
+ struct write_delete_refs_arg arg = {
+ .refs = refs,
+ .stack = stack,
+ .refnames = refnames,
+ .logmsg = msg,
+ .flags = flags,
+ };
+ int err = refs->err;
+ if (err < 0) {
+ goto done;
+ }
+
+ string_list_sort(refnames);
+ err = reftable_stack_reload(stack);
+ if (err) {
+ goto done;
+ }
+ err = reftable_stack_add(stack, &write_delete_refs_table, &arg);
+done:
+ assert(err != REFTABLE_API_ERROR);
+ return err;
+}
+
+static int git_reftable_pack_refs(struct ref_store *ref_store,
+ struct pack_refs_opts *opts)
+{
+ struct git_reftable_ref_store *refs =
+ (struct git_reftable_ref_store *)ref_store;
+
+ int err = refs->err;
+ if (err < 0) {
+ return err;
+ }
+ err = reftable_stack_compact_all(refs->main_stack, NULL);
+ if (err == 0)
+ err = reftable_stack_clean(refs->main_stack);
+
+ return err;
+}
+
+struct write_create_symref_arg {
+ struct git_reftable_ref_store *refs;
+ struct reftable_stack *stack;
+ const char *refname;
+ const char *target;
+ const char *logmsg;
+};
+
+static int write_create_symref_table(struct reftable_writer *writer, void *arg)
+{
+ struct write_create_symref_arg *create =
+ (struct write_create_symref_arg *)arg;
+ uint64_t ts = reftable_stack_next_update_index(create->stack);
+ int err = 0;
+
+ struct reftable_ref_record ref = {
+ .refname = (char *)create->refname,
+ .value_type = REFTABLE_REF_SYMREF,
+ .value.symref = (char *)create->target,
+ .update_index = ts,
+ };
+ reftable_writer_set_limits(writer, ts, ts);
+ err = reftable_writer_add_ref(writer, &ref);
+ if (err == 0) {
+ struct reftable_log_record log = { NULL };
+ struct object_id new_oid;
+ struct object_id old_oid;
+
+ fill_reftable_log_record(&log);
+ log.refname = xstrdup(create->refname);
+ if (!should_log(log.refname)) {
+ return err;
+ }
+ log.update_index = ts;
+ log.value.update.message =
+ xstrndup(create->logmsg,
+ create->refs->write_options.block_size / 2);
+ if (refs_resolve_ref_unsafe(
+ (struct ref_store *)create->refs, create->refname,
+ RESOLVE_REF_READING, &old_oid, NULL)) {
+ log.value.update.old_hash = old_oid.hash;
+ }
+
+ if (refs_resolve_ref_unsafe((struct ref_store *)create->refs,
+ create->target, RESOLVE_REF_READING,
+ &new_oid, NULL)) {
+ log.value.update.new_hash = new_oid.hash;
+ }
+
+ if (log.value.update.old_hash ||
+ log.value.update.new_hash) {
+ err = reftable_writer_add_log(writer, &log);
+ }
+ log.refname = NULL;
+ log.value.update.message = NULL;
+ log.value.update.old_hash = NULL;
+ log.value.update.new_hash = NULL;
+ clear_reftable_log_record(&log);
+ }
+ return err;
+}
+
+static int git_reftable_create_symref(struct ref_store *ref_store,
+ const char *refname, const char *target,
+ const char *logmsg)
+{
+ struct git_reftable_ref_store *refs =
+ (struct git_reftable_ref_store *)ref_store;
+ struct reftable_stack *stack = stack_for(refs, refname);
+ struct write_create_symref_arg arg = { .refs = refs,
+ .stack = stack,
+ .refname = refname,
+ .target = target,
+ .logmsg = logmsg };
+ int err = refs->err;
+ if (err < 0) {
+ goto done;
+ }
+ err = reftable_stack_reload(stack);
+ if (err) {
+ goto done;
+ }
+ err = reftable_stack_add(stack, &write_create_symref_table, &arg);
+done:
+ assert(err != REFTABLE_API_ERROR);
+ return err;
+}
+
+struct write_rename_arg {
+ struct git_reftable_ref_store *refs;
+ struct reftable_stack *stack;
+ const char *oldname;
+ const char *newname;
+ const char *logmsg;
+};
+
+static int write_rename_table(struct reftable_writer *writer, void *argv)
+{
+ struct write_rename_arg *arg = (struct write_rename_arg *)argv;
+ uint64_t ts = reftable_stack_next_update_index(arg->stack);
+ struct reftable_ref_record old_ref = { NULL };
+ struct reftable_ref_record new_ref = { NULL };
+ int err = reftable_stack_read_ref(arg->stack, arg->oldname, &old_ref);
+ struct reftable_ref_record todo[2] = {
+ {
+ .refname = (char *)arg->oldname,
+ .update_index = ts,
+ .value_type = REFTABLE_REF_DELETION,
+ },
+ old_ref,
+ };
+
+ if (err) {
+ goto done;
+ }
+
+ /* git-branch supports a --force, but the check is not atomic. */
+ if (!reftable_stack_read_ref(arg->stack, arg->newname, &new_ref)) {
+ goto done;
+ }
+
+ reftable_writer_set_limits(writer, ts, ts);
+
+ todo[1].update_index = ts;
+ todo[1].refname = (char *)arg->newname;
+
+ err = reftable_writer_add_refs(writer, todo, 2);
+ if (err < 0) {
+ goto done;
+ }
+
+ if (reftable_ref_record_val1(&old_ref)) {
+ uint8_t *val1 = reftable_ref_record_val1(&old_ref);
+ struct reftable_log_record todo[2] = { { NULL } };
+ int firstlog = 0;
+ int lastlog = 2;
+ char *msg = xstrndup(arg->logmsg,
+ arg->refs->write_options.block_size / 2);
+ fill_reftable_log_record(&todo[0]);
+ fill_reftable_log_record(&todo[1]);
+
+ todo[0].refname = xstrdup(arg->oldname);
+ todo[0].update_index = ts;
+ todo[0].value.update.message = msg;
+ todo[0].value.update.old_hash = val1;
+ todo[0].value.update.new_hash = NULL;
+
+ todo[1].refname = xstrdup(arg->newname);
+ todo[1].update_index = ts;
+ todo[1].value.update.old_hash = NULL;
+ todo[1].value.update.new_hash = val1;
+ todo[1].value.update.message = xstrdup(msg);
+
+ if (!should_log(todo[1].refname)) {
+ lastlog--;
+ }
+ if (!should_log(todo[0].refname)) {
+ firstlog++;
+ }
+ err = reftable_writer_add_logs(writer, &todo[firstlog],
+ lastlog - firstlog);
+
+ clear_reftable_log_record(&todo[0]);
+ clear_reftable_log_record(&todo[1]);
+ if (err < 0) {
+ goto done;
+ }
+
+ } else {
+ /* XXX what should we write into the reflog if we rename a
+ * symref? */
+ }
+
+done:
+ assert(err != REFTABLE_API_ERROR);
+ reftable_ref_record_release(&new_ref);
+ reftable_ref_record_release(&old_ref);
+ return err;
+}
+
+static int write_copy_table(struct reftable_writer *writer, void *argv)
+{
+ struct write_rename_arg *arg = (struct write_rename_arg *)argv;
+ uint64_t ts = reftable_stack_next_update_index(arg->stack);
+ struct reftable_ref_record old_ref = { NULL };
+ struct reftable_ref_record new_ref = { NULL };
+ struct reftable_log_record log = { NULL };
+ struct reftable_iterator it = { NULL };
+ int err = reftable_stack_read_ref(arg->stack, arg->oldname, &old_ref);
+ if (err) {
+ goto done;
+ }
+
+ /* git-branch supports a --force, but the check is not atomic. */
+ if (reftable_stack_read_ref(arg->stack, arg->newname, &new_ref) == 0) {
+ goto done;
+ }
+
+ reftable_writer_set_limits(writer, ts, ts);
+
+ FREE_AND_NULL(old_ref.refname);
+ old_ref.refname = xstrdup(arg->newname);
+ old_ref.update_index = ts;
+ err = reftable_writer_add_ref(writer, &old_ref);
+ if (err < 0) {
+ goto done;
+ }
+
+ /* XXX this copies the entire reflog history. Is this the right
+ * semantics? should clear out existing reflog entries for oldname? */
+ if (!should_log(arg->newname))
+ goto done;
+
+ err = reftable_merged_table_seek_log(
+ reftable_stack_merged_table(arg->stack), &it, arg->oldname);
+ if (err < 0) {
+ goto done;
+ }
+ while (1) {
+ int err = reftable_iterator_next_log(&it, &log);
+ if (err < 0) {
+ goto done;
+ }
+
+ if (err > 0 || strcmp(log.refname, arg->oldname)) {
+ break;
+ }
+ FREE_AND_NULL(log.refname);
+ log.refname = xstrdup(arg->newname);
+ reftable_writer_add_log(writer, &log);
+ reftable_log_record_release(&log);
+ }
+
+done:
+ assert(err != REFTABLE_API_ERROR);
+ reftable_ref_record_release(&new_ref);
+ reftable_ref_record_release(&old_ref);
+ reftable_log_record_release(&log);
+ reftable_iterator_destroy(&it);
+ return err;
+}
+
+static int git_reftable_rename_ref(struct ref_store *ref_store,
+ const char *oldrefname,
+ const char *newrefname, const char *logmsg)
+{
+ struct git_reftable_ref_store *refs =
+ (struct git_reftable_ref_store *)ref_store;
+ struct reftable_stack *stack = stack_for(refs, newrefname);
+ struct write_rename_arg arg = {
+ .refs = refs,
+ .stack = stack,
+ .oldname = oldrefname,
+ .newname = newrefname,
+ .logmsg = logmsg,
+ };
+ int err = refs->err;
+ if (err < 0) {
+ goto done;
+ }
+ err = reftable_stack_reload(stack);
+ if (err) {
+ goto done;
+ }
+
+ err = reftable_stack_add(stack, &write_rename_table, &arg);
+done:
+ assert(err != REFTABLE_API_ERROR);
+ return err;
+}
+
+static int git_reftable_copy_ref(struct ref_store *ref_store,
+ const char *oldrefname, const char *newrefname,
+ const char *logmsg)
+{
+ struct git_reftable_ref_store *refs =
+ (struct git_reftable_ref_store *)ref_store;
+ struct reftable_stack *stack = stack_for(refs, newrefname);
+ struct write_rename_arg arg = {
+ .refs = refs,
+ .stack = stack,
+ .oldname = oldrefname,
+ .newname = newrefname,
+ .logmsg = logmsg,
+ };
+ int err = refs->err;
+ if (err < 0) {
+ goto done;
+ }
+ err = reftable_stack_reload(stack);
+ if (err) {
+ goto done;
+ }
+
+ err = reftable_stack_add(stack, &write_copy_table, &arg);
+done:
+ assert(err != REFTABLE_API_ERROR);
+ return err;
+}
+
+struct git_reftable_reflog_ref_iterator {
+ struct ref_iterator base;
+ struct reftable_iterator iter;
+ struct reftable_log_record log;
+ struct object_id oid;
+ struct git_reftable_ref_store *refs;
+
+ /* Used when iterating over worktree & main */
+ struct reftable_merged_table *merged;
+ char *last_name;
+};
+
+static int
+git_reftable_reflog_ref_iterator_advance(struct ref_iterator *ref_iterator)
+{
+ struct git_reftable_reflog_ref_iterator *ri =
+ (struct git_reftable_reflog_ref_iterator *)ref_iterator;
+
+ while (1) {
+ int flags = 0;
+ int err = reftable_iterator_next_log(&ri->iter, &ri->log);
+
+ if (err > 0) {
+ return ITER_DONE;
+ }
+ if (err < 0) {
+ return ITER_ERROR;
+ }
+
+ ri->base.refname = ri->log.refname;
+ if (ri->last_name &&
+ !strcmp(ri->log.refname, ri->last_name)) {
+ /* 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.
+ */
+ continue;
+ }
+
+ if (!refs_resolve_ref_unsafe(&ri->refs->base, ri->log.refname,
+ 0, &ri->oid, &flags)) {
+ error("bad ref for %s", ri->log.refname);
+ continue;
+ }
+
+ free(ri->last_name);
+ ri->last_name = xstrdup(ri->log.refname);
+ ri->base.oid = &ri->oid;
+ ri->base.flags = flags;
+ return ITER_OK;
+ }
+}
+
+static int
+git_reftable_reflog_ref_iterator_peel(struct ref_iterator *ref_iterator,
+ struct object_id *peeled)
+{
+ BUG("not supported.");
+ return -1;
+}
+
+static int
+git_reftable_reflog_ref_iterator_abort(struct ref_iterator *ref_iterator)
+{
+ struct git_reftable_reflog_ref_iterator *ri =
+ (struct git_reftable_reflog_ref_iterator *)ref_iterator;
+ reftable_log_record_release(&ri->log);
+ reftable_iterator_destroy(&ri->iter);
+ if (ri->merged)
+ reftable_merged_table_free(ri->merged);
+ return 0;
+}
+
+static struct ref_iterator_vtable git_reftable_reflog_ref_iterator_vtable = {
+ git_reftable_reflog_ref_iterator_advance,
+ git_reftable_reflog_ref_iterator_peel,
+ git_reftable_reflog_ref_iterator_abort
+};
+
+static struct ref_iterator *
+git_reftable_reflog_iterator_begin(struct ref_store *ref_store)
+{
+ struct git_reftable_ref_store *refs =
+ (struct git_reftable_ref_store *)ref_store;
+ struct git_reftable_reflog_ref_iterator *ri = xcalloc(1, sizeof(*ri));
+ struct reftable_stack *stack = refs->main_stack;
+ struct reftable_merged_table *mt =
+ reftable_stack_merged_table(stack);
+ int err = reftable_merged_table_seek_log(mt, &ri->iter, "");
+
+ ri->refs = refs;
+ if (err < 0) {
+ free(ri);
+ /* XXX how to handle errors in iterator_begin()? */
+ return NULL;
+ }
+ base_ref_iterator_init(&ri->base,
+ &git_reftable_reflog_ref_iterator_vtable, 1);
+ ri->base.oid = &ri->oid;
+
+ return (struct ref_iterator *)ri;
+}
+
+static int git_reftable_for_each_reflog_ent_newest_first(
+ struct ref_store *ref_store, const char *refname, each_reflog_ent_fn fn,
+ void *cb_data)
+{
+ struct reftable_iterator it = { NULL };
+ struct git_reftable_ref_store *refs =
+ (struct git_reftable_ref_store *)ref_store;
+ struct reftable_stack *stack = stack_for(refs, refname);
+ struct reftable_merged_table *mt = NULL;
+ int err = 0;
+ struct reftable_log_record log = { NULL };
+
+ if (refs->err < 0) {
+ return refs->err;
+ }
+ refname = bare_ref_name(refname);
+
+ mt = reftable_stack_merged_table(stack);
+ err = reftable_merged_table_seek_log(mt, &it, refname);
+ while (err == 0) {
+ struct object_id old_oid;
+ struct object_id new_oid;
+ const char *full_committer = "";
+
+ err = reftable_iterator_next_log(&it, &log);
+ if (err > 0) {
+ err = 0;
+ break;
+ }
+ if (err < 0) {
+ break;
+ }
+
+ if (strcmp(log.refname, refname)) {
+ break;
+ }
+
+ oidread(&old_oid, log.value.update.old_hash);
+ oidread(&new_oid, log.value.update.new_hash);
+
+ if (is_null_oid(&old_oid) && is_null_oid(&new_oid)) {
+ /* placeholder for existence. */
+ continue;
+ }
+
+ full_committer = fmt_ident(log.value.update.name,
+ log.value.update.email,
+ WANT_COMMITTER_IDENT,
+ /*date*/ NULL, IDENT_NO_DATE);
+ err = fn(&old_oid, &new_oid, full_committer,
+ log.value.update.time, log.value.update.tz_offset,
+ log.value.update.message, cb_data);
+ if (err)
+ break;
+ }
+
+ reftable_log_record_release(&log);
+ reftable_iterator_destroy(&it);
+ return err;
+}
+
+static int git_reftable_for_each_reflog_ent_oldest_first(
+ struct ref_store *ref_store, const char *refname, each_reflog_ent_fn fn,
+ void *cb_data)
+{
+ struct reftable_iterator it = { NULL };
+ struct git_reftable_ref_store *refs =
+ (struct git_reftable_ref_store *)ref_store;
+ struct reftable_stack *stack = stack_for(refs, refname);
+ struct reftable_merged_table *mt = NULL;
+ struct reftable_log_record *logs = NULL;
+ int cap = 0;
+ int len = 0;
+ int err = 0;
+ int i = 0;
+
+ if (refs->err < 0) {
+ return refs->err;
+ }
+ refname = bare_ref_name(refname);
+ mt = reftable_stack_merged_table(stack);
+ err = reftable_merged_table_seek_log(mt, &it, refname);
+
+ while (err == 0) {
+ struct reftable_log_record log = { NULL };
+ err = reftable_iterator_next_log(&it, &log);
+ if (err > 0) {
+ err = 0;
+ break;
+ }
+ if (err < 0) {
+ break;
+ }
+
+ if (strcmp(log.refname, refname)) {
+ break;
+ }
+
+ if (len == cap) {
+ cap = 2 * cap + 1;
+ logs = realloc(logs, cap * sizeof(*logs));
+ }
+
+ logs[len++] = log;
+ }
+
+ for (i = len; i--;) {
+ struct reftable_log_record *log = &logs[i];
+ struct object_id old_oid;
+ struct object_id new_oid;
+ const char *full_committer = "";
+
+ oidread(&old_oid, log->value.update.old_hash);
+ oidread(&new_oid, log->value.update.new_hash);
+
+ if (is_null_oid(&old_oid) && is_null_oid(&new_oid)) {
+ /* placeholder for existence. */
+ continue;
+ }
+
+ full_committer = fmt_ident(log->value.update.name,
+ log->value.update.email,
+ WANT_COMMITTER_IDENT, NULL,
+ IDENT_NO_DATE);
+ err = fn(&old_oid, &new_oid, full_committer,
+ log->value.update.time, log->value.update.tz_offset,
+ log->value.update.message, cb_data);
+ if (err) {
+ break;
+ }
+ }
+
+ for (i = 0; i < len; i++) {
+ reftable_log_record_release(&logs[i]);
+ }
+ free(logs);
+
+ reftable_iterator_destroy(&it);
+ return err;
+}
+
+static int git_reftable_reflog_exists(struct ref_store *ref_store,
+ const char *refname)
+{
+ struct reftable_iterator it = { NULL };
+ struct git_reftable_ref_store *refs =
+ (struct git_reftable_ref_store *)ref_store;
+ struct reftable_stack *stack = stack_for(refs, refname);
+ struct reftable_merged_table *mt = reftable_stack_merged_table(stack);
+ struct reftable_log_record log = { NULL };
+ int err = refs->err;
+
+ if (err < 0) {
+ goto done;
+ }
+
+ refname = bare_ref_name(refname);
+ err = reftable_merged_table_seek_log(mt, &it, refname);
+ if (err) {
+ goto done;
+ }
+ err = reftable_iterator_next_log(&it, &log);
+ if (err) {
+ goto done;
+ }
+
+ if (strcmp(log.refname, refname)) {
+ err = 1;
+ }
+
+done:
+ reftable_iterator_destroy(&it);
+ reftable_log_record_release(&log);
+ return !err;
+}
+
+struct write_reflog_existence_arg {
+ struct git_reftable_ref_store *refs;
+ const char *refname;
+ struct reftable_stack *stack;
+};
+
+static int write_reflog_existence_table(struct reftable_writer *writer,
+ void *argv)
+{
+ struct write_reflog_existence_arg *arg =
+ (struct write_reflog_existence_arg *)argv;
+ uint64_t ts = reftable_stack_next_update_index(arg->stack);
+ struct reftable_log_record log = { NULL };
+
+ int err = reftable_stack_read_log(arg->stack, arg->refname, &log);
+ if (err <= 0) {
+ goto done;
+ }
+
+ reftable_writer_set_limits(writer, ts, ts);
+
+ log.refname = (char *)arg->refname;
+ log.update_index = ts;
+ log.value_type = REFTABLE_LOG_UPDATE;
+ err = reftable_writer_add_log(writer, &log);
+
+ /* field is not malloced */
+ log.refname = NULL;
+
+done:
+ assert(err != REFTABLE_API_ERROR);
+ reftable_log_record_release(&log);
+ return err;
+}
+
+static int git_reftable_create_reflog(struct ref_store *ref_store,
+ const char *refname,
+ struct strbuf *errmsg)
+{
+ struct git_reftable_ref_store *refs =
+ (struct git_reftable_ref_store *)ref_store;
+ struct reftable_stack *stack = stack_for(refs, refname);
+ struct write_reflog_existence_arg arg = {
+ .refs = refs,
+ .stack = stack,
+ .refname = refname,
+ };
+ int err = refs->err;
+ if (err < 0) {
+ goto done;
+ }
+
+ err = reftable_stack_reload(stack);
+ if (err) {
+ goto done;
+ }
+
+ err = reftable_stack_add(stack, &write_reflog_existence_table, &arg);
+
+done:
+ return err;
+}
+
+struct write_reflog_delete_arg {
+ struct reftable_stack *stack;
+ const char *refname;
+};
+
+static int write_reflog_delete_table(struct reftable_writer *writer, void *argv)
+{
+ struct write_reflog_delete_arg *arg = argv;
+ struct reftable_merged_table *mt =
+ reftable_stack_merged_table(arg->stack);
+ struct reftable_log_record log = { NULL };
+ struct reftable_iterator it = { NULL };
+ uint64_t ts = reftable_stack_next_update_index(arg->stack);
+ int err = reftable_merged_table_seek_log(mt, &it, arg->refname);
+
+ reftable_writer_set_limits(writer, ts, ts);
+ while (err == 0) {
+ struct reftable_log_record tombstone = {
+ .refname = (char *)arg->refname,
+ .update_index = REFTABLE_LOG_DELETION,
+ };
+ err = reftable_iterator_next_log(&it, &log);
+ if (err > 0) {
+ err = 0;
+ break;
+ }
+
+ if (err < 0 || strcmp(log.refname, arg->refname)) {
+ break;
+ }
+ if (log.value_type == REFTABLE_LOG_DELETION)
+ continue;
+
+ tombstone.update_index = log.update_index;
+ err = reftable_writer_add_log(writer, &tombstone);
+ }
+
+ reftable_log_record_release(&log);
+ return err;
+}
+
+static int git_reftable_delete_reflog(struct ref_store *ref_store,
+ const char *refname)
+{
+ struct git_reftable_ref_store *refs =
+ (struct git_reftable_ref_store *)ref_store;
+ struct reftable_stack *stack = stack_for(refs, refname);
+ struct write_reflog_delete_arg arg = {
+ .stack = stack,
+ .refname = refname,
+ };
+ int err = reftable_stack_add(stack, &write_reflog_delete_table, &arg);
+ assert(err != REFTABLE_API_ERROR);
+ return err;
+}
+
+struct reflog_expiry_arg {
+ struct reftable_stack *stack;
+ struct reftable_log_record *records;
+ int len;
+ const char *refname;
+};
+
+static int write_reflog_expiry_table(struct reftable_writer *writer, void *argv)
+{
+ struct reflog_expiry_arg *arg = (struct reflog_expiry_arg *)argv;
+ uint64_t ts = reftable_stack_next_update_index(arg->stack);
+ int i = 0;
+ int live_records = 0;
+ uint64_t max_ts = 0;
+ for (i = 0; i < arg->len; i++) {
+ if (arg->records[i].value_type == REFTABLE_LOG_UPDATE)
+ live_records++;
+
+ if (max_ts < arg->records[i].update_index)
+ max_ts = arg->records[i].update_index;
+ }
+
+ reftable_writer_set_limits(writer, ts, ts);
+ if (live_records == 0) {
+ struct reftable_log_record log = {
+ .refname = (char *)arg->refname,
+ .update_index = max_ts + 1,
+ .value_type = REFTABLE_LOG_UPDATE,
+ /* existence dummy has null new/old oid */
+ };
+ int err;
+ if (log.update_index < ts)
+ log.update_index = ts;
+
+ err = reftable_writer_add_log(writer, &log);
+ if (err) {
+ return err;
+ }
+ }
+
+ for (i = 0; i < arg->len; i++) {
+ int err = reftable_writer_add_log(writer, &arg->records[i]);
+ if (err) {
+ return err;
+ }
+ }
+ return 0;
+}
+
+static int git_reftable_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 in place of the expired entries,
+ 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 some operation issues a
+ git_reftable_pack_refs(), which will compact the entire stack and get
+ rid of deletion entries.
+
+ 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 git_reftable_ref_store *refs =
+ (struct git_reftable_ref_store *)ref_store;
+ struct reftable_stack *stack = stack_for(refs, refname);
+ struct reftable_merged_table *mt = NULL;
+ struct reflog_expiry_arg arg = {
+ .stack = stack,
+ .refname = refname,
+ };
+ struct reftable_log_record *logs = NULL;
+ struct reftable_log_record *rewritten = NULL;
+ struct reftable_ref_record ref_record = { NULL };
+ int logs_len = 0;
+ int logs_cap = 0;
+ int i = 0;
+ uint8_t *last_hash = NULL;
+ struct reftable_iterator it = { NULL };
+ struct reftable_addition *add = NULL;
+ int err = 0;
+ struct object_id oid = { 0 };
+ if (refs->err < 0) {
+ return refs->err;
+ }
+ err = reftable_stack_reload(stack);
+ if (err) {
+ goto done;
+ }
+
+ mt = reftable_stack_merged_table(stack);
+ err = reftable_merged_table_seek_log(mt, &it, refname);
+ if (err < 0) {
+ goto done;
+ }
+
+ err = reftable_stack_new_addition(&add, stack);
+ if (err) {
+ goto done;
+ }
+ if (!reftable_stack_read_ref(stack, refname, &ref_record)) {
+ uint8_t *hash = reftable_ref_record_val1(&ref_record);
+ if (hash)
+ oidread(&oid, hash);
+ }
+
+ prepare_fn(refname, &oid, policy_cb_data);
+ while (1) {
+ struct reftable_log_record log = { NULL };
+ int err = reftable_iterator_next_log(&it, &log);
+ if (err < 0) {
+ goto done;
+ }
+
+ if (err > 0 || strcmp(log.refname, refname)) {
+ break;
+ }
+
+ if (logs_len >= logs_cap) {
+ int new_cap = logs_cap * 2 + 1;
+ logs = realloc(logs, new_cap * sizeof(*logs));
+ logs_cap = new_cap;
+ }
+ logs[logs_len++] = log;
+ }
+
+ rewritten = calloc(logs_len, sizeof(*rewritten));
+ for (i = logs_len - 1; i >= 0; i--) {
+ struct object_id ooid;
+ struct object_id noid;
+ struct reftable_log_record *dest = &rewritten[i];
+
+ *dest = logs[i];
+ oidread(&ooid, logs[i].value.update.old_hash);
+ oidread(&noid, logs[i].value.update.new_hash);
+
+ if (should_prune_fn(&ooid, &noid, 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) {
+ dest->value.update.old_hash = last_hash;
+ }
+ last_hash = logs[i].value.update.new_hash;
+ }
+ }
+
+ arg.records = rewritten;
+ arg.len = logs_len;
+ err = reftable_addition_add(add, &write_reflog_expiry_table, &arg);
+ if (err < 0) {
+ goto done;
+ }
+
+ if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
+ /* future improvement: we could skip writing records that were
+ * not changed. */
+ err = reftable_addition_commit(add);
+ }
+
+done:
+ if (add) {
+ cleanup_fn(policy_cb_data);
+ }
+ assert(err != REFTABLE_API_ERROR);
+ reftable_addition_destroy(add);
+ for (i = 0; i < logs_len; i++)
+ reftable_log_record_release(&logs[i]);
+ free(logs);
+ free(rewritten);
+ reftable_iterator_destroy(&it);
+ return err;
+}
+
+static int git_reftable_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 git_reftable_ref_store *refs =
+ (struct git_reftable_ref_store *)ref_store;
+ struct reftable_stack *stack = stack_for(refs, refname);
+ struct reftable_ref_record ref = { NULL };
+ int err = 0;
+
+ refname = bare_ref_name(refname); /* XXX - in which other cases should
+ we do this? */
+ if (refs->err < 0) {
+ return refs->err;
+ }
+
+ /* This is usually not needed, but Git doesn't signal to ref backend if
+ a subprocess updated the ref DB. So we always check.
+ */
+ err = reftable_stack_reload(stack);
+ if (err) {
+ goto done;
+ }
+
+ err = reftable_stack_read_ref(stack, refname, &ref);
+ if (err > 0) {
+ *failure_errno = ENOENT;
+ err = -1;
+ goto done;
+ }
+ if (err < 0) {
+ 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("Got reftable_ref_record with value type %d",
+ ref.value_type);
+ }
+
+done:
+ assert(err != REFTABLE_API_ERROR);
+ reftable_ref_record_release(&ref);
+ return err;
+}
+
+static int git_reftable_read_symbolic_ref(struct ref_store *ref_store,
+ const char *refname,
+ struct strbuf *referent)
+{
+ struct git_reftable_ref_store *refs =
+ (struct git_reftable_ref_store *)ref_store;
+ struct reftable_stack *stack = stack_for(refs, refname);
+ struct reftable_ref_record ref = { NULL };
+ int err = 0;
+
+ err = reftable_stack_read_ref(stack, refname, &ref);
+ if (err == 0 && ref.value_type == REFTABLE_REF_SYMREF) {
+ strbuf_addstr(referent, ref.value.symref);
+ } else {
+ err = -1;
+ }
+
+ reftable_ref_record_release(&ref);
+ return err;
+}
+
+struct ref_storage_be refs_be_reftable = {
+ .next = &refs_be_files,
+ .name = "reftable",
+ .init = git_reftable_ref_store_create,
+ .init_db = git_reftable_init_db,
+ .transaction_begin = git_reftable_transaction_begin,
+ .transaction_prepare = git_reftable_transaction_prepare,
+ .transaction_finish = git_reftable_transaction_finish,
+ .transaction_abort = git_reftable_transaction_abort,
+ .initial_transaction_commit = git_reftable_transaction_initial_commit,
+
+ .pack_refs = git_reftable_pack_refs,
+ .create_symref = git_reftable_create_symref,
+ .delete_refs = git_reftable_delete_refs,
+ .rename_ref = git_reftable_rename_ref,
+ .copy_ref = git_reftable_copy_ref,
+
+ .iterator_begin = git_reftable_ref_iterator_begin,
+ .read_raw_ref = git_reftable_read_raw_ref,
+ .read_symbolic_ref = git_reftable_read_symbolic_ref,
+
+ .reflog_iterator_begin = git_reftable_reflog_iterator_begin,
+ .for_each_reflog_ent = git_reftable_for_each_reflog_ent_oldest_first,
+ .for_each_reflog_ent_reverse =
+ git_reftable_for_each_reflog_ent_newest_first,
+ .reflog_exists = git_reftable_reflog_exists,
+ .create_reflog = git_reftable_create_reflog,
+ .delete_reflog = git_reftable_delete_reflog,
+ .reflog_expire = git_reftable_reflog_expire,
+};
diff --git a/refs/reftable-backend.h b/refs/reftable-backend.h
new file mode 100644
index 00000000000..bf5fd42229a
--- /dev/null
+++ b/refs/reftable-backend.h
@@ -0,0 +1,8 @@
+#ifndef REFS_REFTABLE_BACKEND_H
+#define REFS_REFTABLE_BACKEND_H
+
+struct ref_store *git_reftable_ref_store_create(struct repository *repo,
+ const char *gitdir,
+ unsigned int store_flags);
+
+#endif /* REFS_REFTABLE_BACKEND_H */
--
gitgitgadget
^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH v2 6/6] refs: always try to do packed transactions for reftable
2023-09-20 13:02 ` [PATCH v2 0/6] RFC: simple " Han-Wen Nienhuys via GitGitGadget
` (4 preceding siblings ...)
2023-09-20 13:02 ` [PATCH v2 5/6] refs: alternate reftable ref backend implementation Han-Wen Nienhuys via GitGitGadget
@ 2023-09-20 13:02 ` Han-Wen Nienhuys via GitGitGadget
2023-09-21 10:01 ` [PATCH v2 0/6] RFC: simple reftable backend Patrick Steinhardt
6 siblings, 0 replies; 15+ messages in thread
From: Han-Wen Nienhuys via GitGitGadget @ 2023-09-20 13:02 UTC (permalink / raw)
To: git; +Cc: Han-Wen Nienhuys, Han-Wen Nienhuys, Han-Wen Nienhuys
From: Han-Wen Nienhuys <hanwen@google.com>
Reftable updates are cheap (compared to packed-refs updates), so do them
always. This also helps exercise this code more in tests.
This should commit should not be merged currently. It fails 55 tests
when running with GIT_TEST_REFTABLE.
Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
---
refs/files-backend.c | 22 +++++++++++++++++-----
1 file changed, 17 insertions(+), 5 deletions(-)
diff --git a/refs/files-backend.c b/refs/files-backend.c
index 2cd596bbeba..0d61a18b4ba 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -2800,6 +2800,7 @@ static int files_transaction_prepare(struct ref_store *ref_store,
int head_type;
struct files_transaction_backend_data *backend_data;
struct ref_transaction *packed_transaction = NULL;
+ int is_reftable = !strcmp(refs->packed_ref_store->be->name, "reftable");
assert(err);
@@ -2809,6 +2810,16 @@ static int files_transaction_prepare(struct ref_store *ref_store,
CALLOC_ARRAY(backend_data, 1);
transaction->backend_data = backend_data;
+ if (is_reftable) {
+ packed_transaction = ref_store_transaction_begin(
+ refs->packed_ref_store, err);
+ if (!packed_transaction) {
+ ret = TRANSACTION_GENERIC_ERROR;
+ goto cleanup;
+ }
+ backend_data->packed_transaction = packed_transaction;
+ }
+
/*
* Fail if a refname appears more than once in the
* transaction. (If we end up splitting up any updates using
@@ -2881,9 +2892,9 @@ static int files_transaction_prepare(struct ref_store *ref_store,
if (ret)
goto cleanup;
- if (update->flags & REF_DELETING &&
- !(update->flags & REF_LOG_ONLY) &&
- !(update->flags & REF_IS_PRUNING)) {
+ if (is_reftable || (update->flags & REF_DELETING &&
+ !(update->flags & REF_LOG_ONLY) &&
+ !(update->flags & REF_IS_PRUNING))) {
/*
* This reference has to be deleted from
* packed-refs if it exists there.
@@ -2909,8 +2920,9 @@ static int files_transaction_prepare(struct ref_store *ref_store,
}
if (packed_transaction) {
- backend_data->packed_transaction_needed = is_packed_transaction_needed(refs->packed_ref_store,
- packed_transaction);
+ backend_data->packed_transaction_needed = is_reftable ||
+ is_packed_transaction_needed(refs->packed_ref_store,
+ packed_transaction);
if (backend_data->packed_transaction_needed) {
ret = ref_transaction_prepare(packed_transaction, err);
/*
--
gitgitgadget
^ permalink raw reply related [flat|nested] 15+ messages in thread* Re: [PATCH v2 0/6] RFC: simple reftable backend
2023-09-20 13:02 ` [PATCH v2 0/6] RFC: simple " Han-Wen Nienhuys via GitGitGadget
` (5 preceding siblings ...)
2023-09-20 13:02 ` [PATCH v2 6/6] refs: always try to do packed transactions for reftable Han-Wen Nienhuys via GitGitGadget
@ 2023-09-21 10:01 ` Patrick Steinhardt
6 siblings, 0 replies; 15+ messages in thread
From: Patrick Steinhardt @ 2023-09-21 10:01 UTC (permalink / raw)
To: Han-Wen Nienhuys via GitGitGadget; +Cc: git, Han-Wen Nienhuys, Han-Wen Nienhuys
[-- Attachment #1: Type: text/plain, Size: 27876 bytes --]
On Wed, Sep 20, 2023 at 01:02:42PM +0000, Han-Wen Nienhuys via GitGitGadget wrote:
> This series comes from a conversation with Patrick Steinhardt at Gitlab, who
> have an interest in a more scalable ref storage system.
>
> I unfortunately don't have business reasons to spend much time on this
> project anymore, and the original, sweeping migration has too many open
> questions.
>
> I thought of an alternate approach, and I wanted to show it as input to
> discussions at the contributor summit.
>
> I think the first part (everything before "refs: alternate reftable ref
> backend implementation") is a good improvement overall, and could be landed
> separately without much tweaking.
>
> The second part ("refs: alternate reftable ref backend implementation" and
> follow-on) is something open for discussion: the alternative "packed
> storage" is based on reftable, but it could conceivably be a different type
> of database/file format too. I think it's attractive to use reftable here,
> because over time more data (symrefs, reflog) could be moved into reftable.
>
> I'm offering this series as a RFC. I hope that someone else (Patrick?) can
> look into getting the bits and pieces of this merged.
I've added this topic to the Contributor's summit such that the project
can discuss what to do about the different proposals that exist around
next-gen reference backends. If the conclusion is that reftables and
this proposal here is still likely to land, then I'm happy to pick it up
and try to get it upstreamed.
I'll have a look at this RFC early next week.
Thanks!
Patrick
> Han-Wen Nienhuys (6):
> refs: construct transaction using a _begin callback
> refs: wrap transaction in a debug-specific transaction
> refs: push lock management into packed backend
> refs: move is_packed_transaction_needed out of packed-backend.c
> refs: alternate reftable ref backend implementation
> refs: always try to do packed transactions for reftable
>
> Makefile | 1 +
> config.mak.uname | 2 +-
> contrib/workdir/git-new-workdir | 2 +-
> refs.c | 13 +-
> refs/debug.c | 87 +-
> refs/files-backend.c | 216 ++--
> refs/packed-backend.c | 149 +--
> refs/packed-backend.h | 19 -
> refs/refs-internal.h | 5 +
> refs/reftable-backend.c | 1658 +++++++++++++++++++++++++++++++
> refs/reftable-backend.h | 8 +
> 11 files changed, 1929 insertions(+), 231 deletions(-)
> create mode 100644 refs/reftable-backend.c
> create mode 100644 refs/reftable-backend.h
>
>
> base-commit: bda494f4043963b9ec9a1ecd4b19b7d1cd9a0518
> Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-1574%2Fhanwen%2Fsimple-reftable-backend-v2
> Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-1574/hanwen/simple-reftable-backend-v2
> Pull-Request: https://github.com/git/git/pull/1574
>
> Range-diff vs v1:
>
> -: ----------- > 1: e99f3d20056 refs: construct transaction using a _begin callback
> -: ----------- > 2: 9a459259330 refs: wrap transaction in a debug-specific transaction
> 1: dea0fbb139a ! 3: 8dedb23eb69 refs: push lock management into packed backend
> @@ Metadata
> ## Commit message ##
> refs: push lock management into packed backend
>
> - Introduces a ref backend method transaction_begin, which for the
> - packed backend takes packed-refs.lock.
> + Take packed-refs.lock in the transaction_begin of the packed backend.
>
> This decouples the files backend from the packed backend, allowing the
> latter to be swapped out by another ref backend.
> @@ Commit message
> Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
>
> ## refs.c ##
> -@@ refs.c: struct ref_transaction *ref_store_transaction_begin(struct ref_store *refs,
> - struct strbuf *err)
> - {
> - struct ref_transaction *tr;
> -+ int ret = 0;
> - assert(err);
> -
> - CALLOC_ARRAY(tr, 1);
> - tr->ref_store = refs;
> -+
> -+ if (refs->be->transaction_begin)
> -+ ret = refs->be->transaction_begin(refs, tr, err);
> -+ if (ret) {
> -+ free(tr);
> -+ return NULL;
> -+ }
> - return tr;
> - }
> -
> -
> - ## refs/debug.c ##
> -@@ refs/debug.c: static int debug_init_db(struct ref_store *refs, struct strbuf *err)
> - return res;
> - }
> -
> -+static int debug_transaction_begin(struct ref_store *refs,
> -+ struct ref_transaction *transaction,
> -+ struct strbuf *err)
> -+{
> -+ struct debug_ref_store *drefs = (struct debug_ref_store *)refs;
> -+ int res;
> -+ transaction->ref_store = drefs->refs;
> -+ res = drefs->refs->be->transaction_begin(drefs->refs, transaction,
> -+ err);
> -+ trace_printf_key(&trace_refs, "transaction_begin: %d \"%s\"\n", res,
> -+ err->buf);
> -+ return res;
> -+}
> -+
> - static int debug_transaction_prepare(struct ref_store *refs,
> - struct ref_transaction *transaction,
> - struct strbuf *err)
> -@@ refs/debug.c: struct ref_storage_be refs_be_debug = {
> - * has a function we should also have a wrapper for it here.
> - * Test the output with "GIT_TRACE_REFS=1".
> - */
> -+ .transaction_begin = debug_transaction_begin,
> - .transaction_prepare = debug_transaction_prepare,
> - .transaction_finish = debug_transaction_finish,
> - .transaction_abort = debug_transaction_abort,
> +@@ refs.c: int ref_transaction_abort(struct ref_transaction *transaction,
> + int ret = 0;
> +
> + switch (transaction->state) {
> +- case REF_TRANSACTION_OPEN:
> +- /* No need to abort explicitly. */
> +- break;
> + case REF_TRANSACTION_PREPARED:
> ++ case REF_TRANSACTION_OPEN:
> ++ /* an OPEN transactions may have a lock. */
> + ret = refs->be->transaction_abort(refs, transaction, err);
> + break;
> + case REF_TRANSACTION_CLOSED:
>
> ## refs/files-backend.c ##
> @@ refs/files-backend.c: static int files_pack_refs(struct ref_store *ref_store,
> @@ refs/files-backend.c: static int files_transaction_finish(struct ref_store *ref_
> - backend_data->packed_transaction = NULL;
> - if (ret)
> - goto cleanup;
> -+ if (backend_data->packed_transaction) {
> ++ if (backend_data->packed_transaction) {
> + if (backend_data->packed_transaction_needed) {
> + ret = ref_transaction_commit(packed_transaction, err);
> + if (ret)
> + goto cleanup;
> -+ /* TODO: leaks on error path. */
> ++
> + ref_transaction_free(packed_transaction);
> + packed_transaction = NULL;
> + backend_data->packed_transaction = NULL;
> @@ refs/files-backend.c: static int files_initial_transaction_commit(struct ref_sto
> ref_transaction_free(packed_transaction);
>
> ## refs/packed-backend.c ##
> +@@ refs/packed-backend.c: static int write_packed_entry(FILE *fh, const char *refname,
> + return 0;
> + }
> +
> +-int packed_refs_lock(struct ref_store *ref_store, int flags, struct strbuf *err)
> ++static int packed_refs_lock(struct ref_store *ref_store, int flags, struct strbuf *err)
> + {
> + struct packed_ref_store *refs =
> + packed_downcast(ref_store, REF_STORE_WRITE | REF_STORE_MAIN,
> +@@ refs/packed-backend.c: int packed_refs_lock(struct ref_store *ref_store, int flags, struct strbuf *err)
> + return 0;
> + }
> +
> +-void packed_refs_unlock(struct ref_store *ref_store)
> ++static void packed_refs_unlock(struct ref_store *ref_store)
> + {
> + struct packed_ref_store *refs = packed_downcast(
> + ref_store,
> +@@ refs/packed-backend.c: void packed_refs_unlock(struct ref_store *ref_store)
> + rollback_lock_file(&refs->lock);
> + }
> +
> +-int packed_refs_is_locked(struct ref_store *ref_store)
> +-{
> +- struct packed_ref_store *refs = packed_downcast(
> +- ref_store,
> +- REF_STORE_READ | REF_STORE_WRITE,
> +- "packed_refs_is_locked");
> +-
> +- return is_lock_file_locked(&refs->lock);
> +-}
> +-
> + /*
> + * The packed-refs header line that we write out. Perhaps other traits
> + * will be added later.
> @@ refs/packed-backend.c: int is_packed_transaction_needed(struct ref_store *ref_store,
>
> struct packed_transaction_backend_data {
> @@ refs/packed-backend.c: static void packed_transaction_cleanup(struct packed_ref_
> transaction->state = REF_TRANSACTION_CLOSED;
> }
>
> -+static int packed_transaction_begin(struct ref_store *ref_store,
> -+ struct ref_transaction *transaction,
> +-
> + static struct ref_transaction *packed_transaction_begin(struct ref_store *ref_store,
> +- struct strbuf *err) {
> +- struct ref_transaction *tr;
> +- CALLOC_ARRAY(tr, 1);
> +- return tr;
> + struct strbuf *err)
> +{
> + struct packed_ref_store *refs = packed_downcast(
> @@ refs/packed-backend.c: static void packed_transaction_cleanup(struct packed_ref_
> + REF_STORE_READ | REF_STORE_WRITE | REF_STORE_ODB,
> + "ref_transaction_begin");
> + struct packed_transaction_backend_data *data;
> -+
> -+ CALLOC_ARRAY(data, 1);
> -+ string_list_init_nodup(&data->updates);
> ++ struct ref_transaction *transaction;
> +
> + if (!is_lock_file_locked(&refs->lock)) {
> + if (packed_refs_lock(ref_store, 0, err))
> -+ /* todo: leaking data */
> -+ return -1;
> ++ return NULL;
> + }
> ++ CALLOC_ARRAY(transaction, 1);
> ++ CALLOC_ARRAY(data, 1);
> ++ string_list_init_nodup(&data->updates);
> + transaction->backend_data = data;
> -+ return 0;
> -+}
> -+
> ++ return transaction;
> + }
> +
> static int packed_transaction_prepare(struct ref_store *ref_store,
> - struct ref_transaction *transaction,
> - struct strbuf *err)
> @@ refs/packed-backend.c: static int packed_transaction_prepare(struct ref_store *ref_store,
> ref_store,
> REF_STORE_READ | REF_STORE_WRITE | REF_STORE_ODB,
> @@ refs/packed-backend.c: static int packed_transaction_prepare(struct ref_store *r
> if (write_with_updates(refs, &data->updates, err))
> goto failure;
>
> -@@ refs/packed-backend.c: struct ref_storage_be refs_be_packed = {
> - .name = "packed",
> - .init = packed_ref_store_create,
> - .init_db = packed_init_db,
> -+ .transaction_begin = packed_transaction_begin,
> - .transaction_prepare = packed_transaction_prepare,
> - .transaction_finish = packed_transaction_finish,
> - .transaction_abort = packed_transaction_abort,
>
> ## refs/packed-backend.h ##
> @@ refs/packed-backend.h: struct ref_store *packed_ref_store_create(struct repository *repo,
> @@ refs/packed-backend.h: struct ref_store *packed_ref_store_create(struct reposito
> /*
> * Return true if `transaction` really needs to be carried out against
> * the specified packed_ref_store, or false if it can be skipped
> -
> - ## refs/refs-internal.h ##
> -@@ refs/refs-internal.h: typedef struct ref_store *ref_store_init_fn(struct repository *repo,
> -
> - typedef int ref_init_db_fn(struct ref_store *refs, struct strbuf *err);
> -
> -+typedef int ref_transaction_begin_fn(struct ref_store *refs,
> -+ struct ref_transaction *transaction,
> -+ struct strbuf *err);
> -+
> - typedef int ref_transaction_prepare_fn(struct ref_store *refs,
> - struct ref_transaction *transaction,
> - struct strbuf *err);
> -@@ refs/refs-internal.h: struct ref_storage_be {
> - ref_store_init_fn *init;
> - ref_init_db_fn *init_db;
> -
> -+ ref_transaction_begin_fn *transaction_begin;
> - ref_transaction_prepare_fn *transaction_prepare;
> - ref_transaction_finish_fn *transaction_finish;
> - ref_transaction_abort_fn *transaction_abort;
> 2: a5cb3adc662 ! 4: 0b8919b05c4 refs: move is_packed_transaction_needed out of packed-backend.c
> @@ refs/files-backend.c: out:
> return ret;
> }
>
> -+
> +/*
> + * Return true if `transaction` really needs to be carried out against
> + * the specified packed_ref_store, or false if it can be skipped
> @@ refs/files-backend.c: out:
> struct files_transaction_backend_data {
> struct ref_transaction *packed_transaction;
> int packed_transaction_needed;
> -@@ refs/files-backend.c: struct ref_storage_be refs_be_files = {
> - .delete_reflog = files_delete_reflog,
> - .reflog_expire = files_reflog_expire
> - };
> -+
>
> ## refs/packed-backend.c ##
> @@ refs/packed-backend.c: error:
> 3: 559c04cee99 ! 5: d5669da57e3 refs: alternate reftable ref backend implementation
> @@ Commit message
> refs: alternate reftable ref backend implementation
>
> This introduces the reftable backend as an alternative to the packed
> - backend. This simplifies the code, because we now longer have to worry
> - about:
> + backend.
> +
> + This is an alternative to the approach which was explored in
> + https://github.com/git/git/pull/1215/. This alternative is simpler,
> + because we now longer have to worry about:
>
> - pseudorefs and the HEAD ref
> - worktrees
> - commands that blur together files and references (cherry-pick, rebase)
>
> This deviates from the spec that in
> - Documentation/technical/reftable.txt. It might be possible to update
> - the code such that all writes by default go to reftable directly. Then
> - the result would be compatible with an implementation that writes only
> - reftable (the reftable lock would still prevent races) relative to an
> - implementation that disregards loose refs. Or, JGit could be adapted
> - to follow this implementation.
> + Documentation/technical/reftable.txt. It might be possible to update the
> + code such that all writes by default go to reftable directly. Then the
> + result would be compatible with an implementation that writes only
> + reftable (the reftable lock would still prevent races), but something
> + must be done about the HEAD ref (which JGit keeps in reftable too.)
> + Alternatively, JGit could be adapted to follow this implementation:
> + despite the code being there for 4 years now, I haven't heard of anyone
> + using it in production (exactly because CGit does not support it).
>
> For this incremental path, the reftable format is arguably more
> complex than necessary, as
>
> - packed-refs doesn't support symrefs
> - - reflogs aren't moved into reftable/
> + - reflogs aren't moved into reftable
>
> on the other hand, the code is already there, and it's well-structured
> and well-tested.
>
> - This implementation is a prototype. To test, you need to do `export
> - GIT_TEST_REFTABLE=1`. Doing so creates a handful of errors in the
> - test-suite, most seemingly related to the new behavior of pack-refs
> - (which creates a reftable/ dir and not a packed-refs file.), but it
> - seems overseeable.
> + refs/reftable-backend.c was created by cannibalizing the first version
> + of reftable support (github PR 1215 as mentioned above). It supports
> + reflogs and symrefs, even though those features are never exercised.
> +
> + This implementation is a prototype, for the following reasons:
> +
> + - no considerations of backward compatibility and configuring an
> + extension
> + - no support for converting between packed-refs and reftable
> + - no documentation
> + - test failures when setting GIT_TEST_REFTABLE=1.
>
> Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
>
> @@ contrib/workdir/git-new-workdir: trap cleanup $siglist
> case $x in
>
> ## refs/files-backend.c ##
> +@@
> + #include "../git-compat-util.h"
> ++#include "../abspath.h"
> + #include "../config.h"
> + #include "../copy.h"
> + #include "../environment.h"
> @@
> #include "refs-internal.h"
> #include "ref-cache.h"
> @@ refs/files-backend.c
> #include "../iterator.h"
> #include "../dir-iterator.h"
> @@ refs/files-backend.c: static struct ref_store *files_ref_store_create(struct repository *repo,
> + struct files_ref_store *refs = xcalloc(1, sizeof(*refs));
> + struct ref_store *ref_store = (struct ref_store *)refs;
> + struct strbuf sb = STRBUF_INIT;
> ++ int has_reftable, has_packed;
> +
> + base_ref_store_init(ref_store, repo, gitdir, &refs_be_files);
> refs->store_flags = flags;
> get_common_dir_noenv(&sb, gitdir);
> refs->gitcommondir = strbuf_detach(&sb, NULL);
> -+
> -+ /* TODO: should look at the repo to decide whether to use packed-refs or
> -+ * reftable. */
> - refs->packed_ref_store =
> +- refs->packed_ref_store =
> - packed_ref_store_create(repo, refs->gitcommondir, flags);
> -+ git_env_bool("GIT_TEST_REFTABLE", 0)
> ++
> ++ strbuf_addf(&sb, "%s/reftable", refs->gitcommondir);
> ++ has_reftable = is_directory(sb.buf);
> ++ strbuf_reset(&sb);
> ++ strbuf_addf(&sb, "%s/packed-refs", refs->gitcommondir);
> ++ has_packed = file_exists(sb.buf);
> ++
> ++ if (!has_packed && !has_reftable)
> ++ has_reftable = git_env_bool("GIT_TEST_REFTABLE", 0);
> ++
> ++ refs->packed_ref_store = has_reftable
> + ? git_reftable_ref_store_create(repo, refs->gitcommondir, flags)
> + : packed_ref_store_create(repo, refs->gitcommondir, flags);
>
> chdir_notify_reparent("files-backend $GIT_DIR", &refs->base.gitdir);
> chdir_notify_reparent("files-backend $GIT_COMMONDIR",
>
> - ## refs/packed-backend.c ##
> -@@ refs/packed-backend.c: static int write_packed_entry(FILE *fh, const char *refname,
> - return 0;
> - }
> -
> --int packed_refs_lock(struct ref_store *ref_store, int flags, struct strbuf *err)
> -+static int packed_refs_lock(struct ref_store *ref_store, int flags, struct strbuf *err)
> - {
> - struct packed_ref_store *refs =
> - packed_downcast(ref_store, REF_STORE_WRITE | REF_STORE_MAIN,
> -@@ refs/packed-backend.c: int packed_refs_lock(struct ref_store *ref_store, int flags, struct strbuf *err)
> - return 0;
> - }
> -
> --void packed_refs_unlock(struct ref_store *ref_store)
> -+static void packed_refs_unlock(struct ref_store *ref_store)
> - {
> - struct packed_ref_store *refs = packed_downcast(
> - ref_store,
> -@@ refs/packed-backend.c: void packed_refs_unlock(struct ref_store *ref_store)
> - rollback_lock_file(&refs->lock);
> - }
> -
> --int packed_refs_is_locked(struct ref_store *ref_store)
> --{
> -- struct packed_ref_store *refs = packed_downcast(
> -- ref_store,
> -- REF_STORE_READ | REF_STORE_WRITE,
> -- "packed_refs_is_locked");
> --
> -- return is_lock_file_locked(&refs->lock);
> --}
> --
> - /*
> - * The packed-refs header line that we write out. Perhaps other traits
> - * will be added later.
> -
> ## refs/refs-internal.h ##
> @@ refs/refs-internal.h: struct ref_storage_be {
> };
> @@ refs/reftable-backend.c (new)
> +#include "../worktree.h"
> +#include "refs-internal.h"
> +#include "reftable-backend.h"
> ++#include "../repository.h"
> +
> +extern struct ref_storage_be refs_be_reftable;
> +
> @@ refs/reftable-backend.c (new)
> + return &ri->base;
> +}
> +
> -+static int fixup_symrefs(struct ref_store *ref_store,
> -+ struct ref_transaction *transaction)
> -+{
> -+ struct strbuf referent = STRBUF_INIT;
> -+ int i = 0;
> -+ int err = 0;
> -+
> -+ for (i = 0; i < transaction->nr; i++) {
> -+ struct ref_update *update = transaction->updates[i];
> -+ struct object_id old_oid;
> -+ int failure_errno;
> -+
> -+ err = git_reftable_read_raw_ref(ref_store, update->refname,
> -+ &old_oid, &referent,
> -+ /* mutate input, like
> -+ files-backend.c */
> -+ &update->type, &failure_errno);
> -+ if (err < 0 && failure_errno == ENOENT &&
> -+ is_null_oid(&update->old_oid)) {
> -+ err = 0;
> -+ }
> -+ if (err < 0)
> -+ goto done;
> -+
> -+ if (!(update->type & REF_ISSYMREF))
> -+ continue;
> -+
> -+ if (update->flags & REF_NO_DEREF) {
> -+ /* what should happen here? See files-backend.c
> -+ * lock_ref_for_update. */
> -+ } else {
> -+ /*
> -+ 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.
> -+ */
> -+ int new_flags = update->flags;
> -+ struct ref_update *new_update = NULL;
> -+
> -+ /* if this is an update for HEAD, should also record a
> -+ log entry for HEAD? See files-backend.c,
> -+ split_head_update()
> -+ */
> -+ new_update = ref_transaction_add_update(
> -+ transaction, referent.buf, new_flags,
> -+ &update->new_oid, &update->old_oid,
> -+ update->msg);
> -+ new_update->parent_update = update;
> -+
> -+ /* files-backend sets REF_LOG_ONLY here. */
> -+ update->flags |= REF_NO_DEREF | REF_LOG_ONLY;
> -+ update->flags &= ~REF_HAVE_OLD;
> -+ }
> -+ }
> -+
> -+done:
> -+ assert(err != REFTABLE_API_ERROR);
> -+ strbuf_release(&referent);
> -+ return err;
> -+}
> -+
> -+static int git_reftable_transaction_prepare(struct ref_store *ref_store,
> -+ struct ref_transaction *transaction,
> -+ struct strbuf *errbuf)
> ++static struct ref_transaction *git_reftable_transaction_begin(struct ref_store *ref_store,
> ++ struct strbuf *errbuf)
> +{
> + struct git_reftable_ref_store *refs =
> + (struct git_reftable_ref_store *)ref_store;
> + struct reftable_addition *add = NULL;
> -+ struct reftable_stack *stack = stack_for(
> -+ refs,
> -+ transaction->nr ? transaction->updates[0]->refname : NULL);
> -+ int i;
> ++ struct ref_transaction *transaction = NULL;
> ++ struct reftable_stack *stack = refs->main_stack;
> +
> + int err = refs->err;
> + if (err < 0) {
> @@ refs/reftable-backend.c (new)
> +
> + err = reftable_stack_new_addition(&add, stack);
> + if (err) {
> ++ strbuf_addf(errbuf, "reftable: transaction begin: %s",
> ++ reftable_error_str(err));
> + goto done;
> + }
> +
> -+ for (i = 0; i < transaction->nr; i++) {
> -+ struct ref_update *u = transaction->updates[i];
> -+ 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(
> -+ errbuf,
> -+ "trying to write ref '%s' with nonexistent object %s",
> -+ u->refname, oid_to_hex(&u->new_oid));
> -+ err = -1;
> -+ goto done;
> -+ }
> -+ }
> -+ }
> -+
> -+ err = fixup_symrefs(ref_store, transaction);
> -+ if (err) {
> -+ goto done;
> -+ }
> -+
> ++ CALLOC_ARRAY(transaction, 1);
> + transaction->backend_data = add;
> -+ transaction->state = REF_TRANSACTION_PREPARED;
> -+
> +done:
> -+ assert(err != REFTABLE_API_ERROR);
> -+ if (err < 0) {
> -+ if (add) {
> -+ reftable_addition_destroy(add);
> -+ add = NULL;
> -+ }
> -+ transaction->state = REF_TRANSACTION_CLOSED;
> -+ if (!errbuf->len)
> -+ strbuf_addf(errbuf, "reftable: transaction prepare: %s",
> -+ reftable_error_str(err));
> -+ }
> ++ return transaction;
> ++}
> +
> -+ return err;
> ++static int git_reftable_transaction_prepare(struct ref_store *ref_store,
> ++ struct ref_transaction *transaction,
> ++ struct strbuf *errbuf)
> ++{
> ++ transaction->state = REF_TRANSACTION_PREPARED;
> ++ return 0;
> +}
> +
> +static int git_reftable_transaction_abort(struct ref_store *ref_store,
> @@ refs/reftable-backend.c (new)
> + struct ref_transaction *transaction,
> + struct strbuf *errmsg)
> +{
> ++ struct git_reftable_ref_store *refs =
> ++ (struct git_reftable_ref_store *)transaction->ref_store;
> + struct reftable_addition *add =
> + (struct reftable_addition *)transaction->backend_data;
> + int err = 0;
> @@ refs/reftable-backend.c (new)
> +
> + err = reftable_addition_commit(add);
> +
> ++ if (!err)
> ++ err = reftable_stack_auto_compact(refs->main_stack);
> +done:
> + assert(err != REFTABLE_API_ERROR);
> + reftable_addition_destroy(add);
> @@ refs/reftable-backend.c (new)
> + .name = "reftable",
> + .init = git_reftable_ref_store_create,
> + .init_db = git_reftable_init_db,
> ++ .transaction_begin = git_reftable_transaction_begin,
> + .transaction_prepare = git_reftable_transaction_prepare,
> + .transaction_finish = git_reftable_transaction_finish,
> + .transaction_abort = git_reftable_transaction_abort,
> -: ----------- > 6: 2cf743031ab refs: always try to do packed transactions for reftable
>
> --
> gitgitgadget
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