Merge pull request #172 from bnbarham/update-lmdb

[lmdb] Update LMDB to latest upstream

Author: bnbarham

lib/Database/lmdb/COPYRIGHT

@@ -1,4 +1,4 @@
-Copyright 2011-2018 Howard Chu, Symas Corp.
+Copyright 2011-2021 Howard Chu, Symas Corp.
 All rights reserved.
 
 Redistribution and use in source and binary forms, with or without

lib/Database/lmdb/lmdb++.h

@@ -1276,12 +1276,11 @@ class lmdb::txn {
    * @post `handle() == nullptr`
    */
   void commit() {
+    // INDEXSTOREDB START (prevent double free)
     MDB_txn *hnd = _handle;
-    // Clear _handle before the call otherwise if an error is thrown then
-    // the destructor will do abort() which will be double-free since
-    // txn_commit will have already freed the handle object.
     _handle = nullptr;
     lmdb::txn_commit(hnd);
+    // INDEXSTOREDB END
   }
 
   /**
@@ -1290,8 +1289,11 @@ class lmdb::txn {
    * @post `handle() == nullptr`
    */
   void abort() noexcept {
-    lmdb::txn_abort(_handle);
+    // INDEXSTOREDB START (prevent double free)
+    MDB_txn *hnd = _handle;
     _handle = nullptr;
+    lmdb::txn_abort(hnd);
+    // INDEXSTOREDB END
   }
 
   /**

lib/Database/lmdb/lmdb.h

@@ -610,7 +610,7 @@ int  mdb_env_create(MDB_env **env);
 	 *	<li>#MDB_NOTLS
 	 *		Don't use Thread-Local Storage. Tie reader locktable slots to
 	 *		#MDB_txn objects instead of to threads. I.e. #mdb_txn_reset() keeps
-	 *		the slot reseved for the #MDB_txn object. A thread may use parallel
+	 *		the slot reserved for the #MDB_txn object. A thread may use parallel
 	 *		read-only transactions. A read-only transaction may span threads if
 	 *		the user synchronizes its use. Applications that multiplex many
 	 *		user threads over individual OS threads need this option. Such an
@@ -968,7 +968,7 @@ void *mdb_env_get_userctx(MDB_env *env);
 typedef void MDB_assert_func(MDB_env *env, const char *msg);
 
 	/** Set or reset the assert() callback of the environment.
-	 * Disabled if liblmdb is buillt with NDEBUG.
+	 * Disabled if liblmdb is built with NDEBUG.
 	 * @note This hack should become obsolete as lmdb's error handling matures.
 	 * @param[in] env An environment handle returned by #mdb_env_create().
 	 * @param[in] func An #MDB_assert_func function, or 0.