diff --git a/mdbx.h b/mdbx.h
index dbf622a8..e971ade5 100644
--- a/mdbx.h
+++ b/mdbx.h
@@ -5124,6 +5124,10 @@ MDBX_NOTHROW_PURE_FUNCTION LIBMDBX_API void *mdbx_cursor_get_userctx(const MDBX_
* the same table handle as it was created with. This may be done whether the
* previous transaction is live or dead.
*
+ * If the transaction is nested, then the cursor should not be used in its parent transaction.
+ * Otherwise it is no way to restore state if this nested transaction will be aborted,
+ * nor impossible to define the expected behavior.
+ *
* \note In contrast to LMDB, the MDBX required that any opened cursors can be
* reused and must be freed explicitly, regardless ones was opened in a
* read-only or write transaction. The REASON for this is eliminates ambiguity
@@ -5148,6 +5152,10 @@ LIBMDBX_API int mdbx_cursor_bind(MDBX_txn *txn, MDBX_cursor *cursor, MDBX_dbi db
* the original DBI-handle internally. Thus it could be renewed with any running
* transaction or closed.
*
+ * If the transaction is nested, then the cursor should not be used in its parent transaction.
+ * Otherwise it is no way to restore state if this nested transaction will be aborted,
+ * nor impossible to define the expected behavior.
+ *
* \see mdbx_cursor_renew()
* \see mdbx_cursor_bind()
* \see mdbx_cursor_close()
@@ -5232,6 +5240,10 @@ LIBMDBX_API void mdbx_cursor_close(MDBX_cursor *cursor);
* Unbinds either closes all cursors associated (opened or renewed) with
* a given transaction in a bulk with minimal overhead.
*
+ * A transaction should not be nested, since in this case no way to restore
+ * state if this nested transaction will be aborted, nor impossible to define
+ * the expected behavior.
+ *
* \see mdbx_cursor_unbind()
* \see mdbx_cursor_close()
*
@@ -5245,7 +5257,7 @@ LIBMDBX_API void mdbx_cursor_close(MDBX_cursor *cursor);
* some possible errors are:
* \retval MDBX_THREAD_MISMATCH Given transaction is not owned
* by current thread.
- * \retval MDBX_BAD_TXN Given transaction is invalid or has
+ * \retval MDBX_BAD_TXN Given transaction is invalid, nested or has
* a child/nested transaction transaction. */
LIBMDBX_API int mdbx_txn_release_all_cursors_ex(const MDBX_txn *txn, bool unbind, size_t *count);
@@ -5255,6 +5267,10 @@ LIBMDBX_API int mdbx_txn_release_all_cursors_ex(const MDBX_txn *txn, bool unbind
* Unbinds either closes all cursors associated (opened or renewed) with
* a given transaction in a bulk with minimal overhead.
*
+ * A transaction should not be nested, since in this case no way to restore
+ * state if this nested transaction will be aborted, nor impossible to define
+ * the expected behavior.
+ *
* \see mdbx_cursor_unbind()
* \see mdbx_cursor_close()
*
@@ -5266,7 +5282,7 @@ LIBMDBX_API int mdbx_txn_release_all_cursors_ex(const MDBX_txn *txn, bool unbind
* some possible errors are:
* \retval MDBX_THREAD_MISMATCH Given transaction is not owned
* by current thread.
- * \retval MDBX_BAD_TXN Given transaction is invalid or has
+ * \retval MDBX_BAD_TXN Given transaction is invalid, nested or has
* a child/nested transaction transaction. */
LIBMDBX_INLINE_API(int, mdbx_txn_release_all_cursors, (const MDBX_txn *txn, bool unbind)) {
return mdbx_txn_release_all_cursors_ex(txn, unbind, NULL);
diff --git a/src/api-cursor.c b/src/api-cursor.c
index 4a4b34c8..05c98b4b 100644
--- a/src/api-cursor.c
+++ b/src/api-cursor.c
@@ -44,8 +44,10 @@ int mdbx_cursor_bind(MDBX_txn *txn, MDBX_cursor *mc, MDBX_dbi dbi) {
if (unlikely(!mc))
return LOG_IFERR(MDBX_EINVAL);
- if (unlikely(mc->signature != cur_signature_ready4dispose && mc->signature != cur_signature_live))
- return LOG_IFERR(MDBX_EBADSIGN);
+ if (unlikely(mc->signature != cur_signature_ready4dispose && mc->signature != cur_signature_live)) {
+ int rc = (mc->signature == cur_signature_wait4eot) ? MDBX_EINVAL : MDBX_EBADSIGN;
+ return LOG_IFERR(rc);
+ }
int rc = check_txn(txn, MDBX_TXN_BLOCKED);
if (unlikely(rc != MDBX_SUCCESS))
@@ -58,24 +60,12 @@ int mdbx_cursor_bind(MDBX_txn *txn, MDBX_cursor *mc, MDBX_dbi dbi) {
if (unlikely(dbi == FREE_DBI && !(txn->flags & MDBX_TXN_RDONLY)))
return LOG_IFERR(MDBX_EACCESS);
- if (unlikely(mc->backup)) /* Cursor from parent transaction */ {
- cASSERT(mc, mc->signature == cur_signature_live);
- if (unlikely(cursor_dbi(mc) != dbi ||
- /* paranoia */ mc->signature != cur_signature_live || mc->txn != txn))
- return LOG_IFERR(MDBX_EINVAL);
-
- cASSERT(mc, mc->tree == &txn->dbs[dbi]);
- cASSERT(mc, mc->clc == &txn->env->kvs[dbi].clc);
- cASSERT(mc, cursor_dbi(mc) == dbi);
- return likely(cursor_dbi(mc) == dbi &&
- /* paranoia */ mc->signature == cur_signature_live && mc->txn == txn)
- ? MDBX_SUCCESS
- : LOG_IFERR(MDBX_EINVAL) /* Disallow change DBI in nested
- transactions */
- ;
- }
+ if (unlikely(mc->backup)) /* Cursor from parent transaction */
+ LOG_IFERR(MDBX_EINVAL);
if (mc->signature == cur_signature_live) {
+ if (mc->txn == txn && cursor_dbi(mc) == dbi)
+ return MDBX_SUCCESS;
rc = mdbx_cursor_unbind(mc);
if (unlikely(rc != MDBX_SUCCESS))
return rc;
@@ -100,25 +90,22 @@ int mdbx_cursor_unbind(MDBX_cursor *mc) {
return (mc->signature == cur_signature_ready4dispose) ? MDBX_SUCCESS : LOG_IFERR(MDBX_EBADSIGN);
if (unlikely(mc->backup)) /* Cursor from parent transaction */
+ /* TODO: реализовать при переходе на двусвязный список курсоров */
return LOG_IFERR(MDBX_EINVAL);
- eASSERT(nullptr, mc->txn && mc->txn->signature == txn_signature);
- cASSERT(mc, mc->signature == cur_signature_live);
- cASSERT(mc, !mc->backup);
if (unlikely(!mc->txn || mc->txn->signature != txn_signature)) {
ERROR("Wrong cursor's transaction %p 0x%x", __Wpedantic_format_voidptr(mc->txn), mc->txn ? mc->txn->signature : 0);
return LOG_IFERR(MDBX_PROBLEM);
}
+
if (mc->next != mc) {
- const size_t dbi = (kvx_t *)mc->clc - mc->txn->env->kvs;
- cASSERT(mc, cursor_dbi(mc) == dbi);
+ const size_t dbi = cursor_dbi(mc);
cASSERT(mc, dbi < mc->txn->n_dbi);
+ cASSERT(mc, &mc->txn->env->kvs[dbi].clc == mc->clc);
if (dbi < mc->txn->n_dbi) {
MDBX_cursor **prev = &mc->txn->cursors[dbi];
- while (*prev) {
+ while (/* *prev && */ *prev != mc) {
ENSURE(mc->txn->env, (*prev)->signature == cur_signature_live || (*prev)->signature == cur_signature_wait4eot);
- if (*prev == mc)
- break;
prev = &(*prev)->next;
}
cASSERT(mc, *prev == mc);
@@ -219,30 +206,34 @@ again:
int mdbx_txn_release_all_cursors_ex(const MDBX_txn *txn, bool unbind, size_t *count) {
int rc = check_txn(txn, MDBX_TXN_FINISHED | MDBX_TXN_HAS_CHILD);
+ if (unlikely(rc != MDBX_SUCCESS))
+ return LOG_IFERR(rc);
+ if (unlikely(txn->parent)) {
+ rc = MDBX_BAD_TXN;
+ ERROR("%s, err %d", "must not unbind or close cursors for a nested txn", rc);
+ return rc;
+ }
+
size_t n = 0;
- if (likely(rc == MDBX_SUCCESS)) {
- TXN_FOREACH_DBI_FROM(txn, i, MAIN_DBI) {
- while (txn->cursors[i]) {
- ++n;
- MDBX_cursor *mc = txn->cursors[i];
- ENSURE(nullptr, mc->signature == cur_signature_live && (mc->next != mc) && !mc->backup);
- txn->cursors[i] = mc->next;
- mc->next = mc;
- if (unbind) {
- be_poor(mc);
- mc->signature = cur_signature_ready4dispose;
- } else {
- mc->signature = 0;
- osal_free(mc);
- }
+ TXN_FOREACH_DBI_FROM(txn, i, MAIN_DBI) {
+ while (txn->cursors[i]) {
+ ++n;
+ MDBX_cursor *mc = txn->cursors[i];
+ ENSURE(nullptr, mc->signature == cur_signature_live && (mc->next != mc) && !mc->backup);
+ txn->cursors[i] = mc->next;
+ mc->next = mc;
+ if (unbind) {
+ be_poor(mc);
+ mc->signature = cur_signature_ready4dispose;
+ } else {
+ mc->signature = 0;
+ osal_free(mc);
}
}
- } else {
- LOG_IFERR(rc);
}
if (count)
*count = n;
- return rc;
+ return MDBX_SUCCESS;
}
int mdbx_cursor_compare(const MDBX_cursor *l, const MDBX_cursor *r, bool ignore_multival) {