mdbx: изменение лицензии и реструктуризация исходного кода.

src/api-extra.c

@@ -0,0 +1,117 @@
+/// \copyright SPDX-License-Identifier: Apache-2.0
+/// \author Леонид Юрьев aka Leonid Yuriev <leo@yuriev.ru> \date 2015-2024
+
+#include "internals.h"
+
+/*------------------------------------------------------------------------------
+ * Readers API */
+
+__cold int mdbx_reader_list(const MDBX_env *env, MDBX_reader_list_func *func,
+                            void *ctx) {
+  int rc = check_env(env, true);
+  if (unlikely(rc != MDBX_SUCCESS))
+    return rc;
+
+  if (unlikely(!func))
+    return MDBX_EINVAL;
+
+  rc = MDBX_RESULT_TRUE;
+  int serial = 0;
+  lck_t *const lck = env->lck_mmap.lck;
+  if (likely(lck)) {
+    const size_t snap_nreaders =
+        atomic_load32(&lck->rdt_length, mo_AcquireRelease);
+    for (size_t i = 0; i < snap_nreaders; i++) {
+      const reader_slot_t *r = lck->rdt + i;
+    retry_reader:;
+      const uint32_t pid = atomic_load32(&r->pid, mo_AcquireRelease);
+      if (!pid)
+        continue;
+      txnid_t txnid = safe64_read(&r->txnid);
+      const uint64_t tid = atomic_load64(&r->tid, mo_Relaxed);
+      const pgno_t pages_used =
+          atomic_load32(&r->snapshot_pages_used, mo_Relaxed);
+      const uint64_t reader_pages_retired =
+          atomic_load64(&r->snapshot_pages_retired, mo_Relaxed);
+      if (unlikely(txnid != safe64_read(&r->txnid) ||
+                   pid != atomic_load32(&r->pid, mo_AcquireRelease) ||
+                   tid != atomic_load64(&r->tid, mo_Relaxed) ||
+                   pages_used !=
+                       atomic_load32(&r->snapshot_pages_used, mo_Relaxed) ||
+                   reader_pages_retired !=
+                       atomic_load64(&r->snapshot_pages_retired, mo_Relaxed)))
+        goto retry_reader;
+
+      eASSERT(env, txnid > 0);
+      if (txnid >= SAFE64_INVALID_THRESHOLD)
+        txnid = 0;
+
+      size_t bytes_used = 0;
+      size_t bytes_retained = 0;
+      uint64_t lag = 0;
+      if (txnid) {
+        troika_t troika = meta_tap(env);
+      retry_header:;
+        const meta_ptr_t head = meta_recent(env, &troika);
+        const uint64_t head_pages_retired =
+            unaligned_peek_u64_volatile(4, head.ptr_v->pages_retired);
+        if (unlikely(meta_should_retry(env, &troika) ||
+                     head_pages_retired != unaligned_peek_u64_volatile(
+                                               4, head.ptr_v->pages_retired)))
+          goto retry_header;
+
+        lag = (head.txnid - txnid) / xMDBX_TXNID_STEP;
+        bytes_used = pgno2bytes(env, pages_used);
+        bytes_retained = (head_pages_retired > reader_pages_retired)
+                             ? pgno2bytes(env, (pgno_t)(head_pages_retired -
+                                                        reader_pages_retired))
+                             : 0;
+      }
+      rc = func(ctx, ++serial, (unsigned)i, pid, (mdbx_tid_t)((intptr_t)tid),
+                txnid, lag, bytes_used, bytes_retained);
+      if (unlikely(rc != MDBX_SUCCESS))
+        break;
+    }
+  }
+
+  return rc;
+}
+
+__cold int mdbx_reader_check(MDBX_env *env, int *dead) {
+  if (dead)
+    *dead = 0;
+  return mvcc_cleanup_dead(env, false, dead);
+}
+
+/*------------------------------------------------------------------------------
+ * Locking API */
+
+int mdbx_txn_lock(MDBX_env *env, bool dont_wait) {
+  int rc = check_env(env, true);
+  if (unlikely(rc != MDBX_SUCCESS))
+    return rc;
+
+  if (unlikely(env->flags & MDBX_RDONLY))
+    return MDBX_EACCESS;
+  if (unlikely(env->basal_txn->owner ||
+               (env->basal_txn->flags & MDBX_TXN_FINISHED) == 0))
+    return MDBX_BUSY;
+
+  return lck_txn_lock(env, dont_wait);
+}
+
+int mdbx_txn_unlock(MDBX_env *env) {
+  int rc = check_env(env, true);
+  if (unlikely(rc != MDBX_SUCCESS))
+    return rc;
+
+  if (unlikely(env->flags & MDBX_RDONLY))
+    return MDBX_EACCESS;
+  if (unlikely(env->basal_txn->owner != osal_thread_self()))
+    return MDBX_THREAD_MISMATCH;
+  if (unlikely((env->basal_txn->flags & MDBX_TXN_FINISHED) == 0))
+    return MDBX_BUSY;
+
+  lck_txn_unlock(env);
+  return MDBX_SUCCESS;
+}