1 files changed, 48 insertions, 0 deletions
diff --git a/src/rocksdb/include/rocksdb/snapshot.h b/src/rocksdb/include/rocksdb/snapshot.h
new file mode 100644
index 000000000..6a7212d60
--- /dev/null
+++ b/src/rocksdb/include/rocksdb/snapshot.h
@@ -0,0 +1,48 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+
+#pragma once
+
+#include "rocksdb/types.h"
+
+namespace ROCKSDB_NAMESPACE {
+
+class DB;
+
+// Abstract handle to particular state of a DB.
+// A Snapshot is an immutable object and can therefore be safely
+// accessed from multiple threads without any external synchronization.
+//
+// To Create a Snapshot, call DB::GetSnapshot().
+// To Destroy a Snapshot, call DB::ReleaseSnapshot(snapshot).
+class Snapshot {
+ public:
+  // returns Snapshot's sequence number
+  virtual SequenceNumber GetSequenceNumber() const = 0;
+
+ protected:
+  virtual ~Snapshot();
+};
+
+// Simple RAII wrapper class for Snapshot.
+// Constructing this object will create a snapshot.  Destructing will
+// release the snapshot.
+class ManagedSnapshot {
+ public:
+  explicit ManagedSnapshot(DB* db);
+
+  // Instead of creating a snapshot, take ownership of the input snapshot.
+  ManagedSnapshot(DB* db, const Snapshot* _snapshot);
+
+  ~ManagedSnapshot();
+
+  const Snapshot* snapshot();
+
+ private:
+  DB* db_;
+  const Snapshot* snapshot_;
+};
+
+}  // namespace ROCKSDB_NAMESPACE