blob: a96eb763e3ec358863abe8ea1451b0daaa7ffe2a [file] [log] [blame]
// 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 {
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 {
// returns Snapshot's sequence number
virtual SequenceNumber GetSequenceNumber() const = 0;
virtual ~Snapshot();
// Simple RAII wrapper class for Snapshot.
// Constructing this object will create a snapshot. Destructing will
// release the snapshot.
class ManagedSnapshot {
explicit ManagedSnapshot(DB* db);
// Instead of creating a snapshot, take ownership of the input snapshot.
ManagedSnapshot(DB* db, const Snapshot* _snapshot);
const Snapshot* snapshot();
DB* db_;
const Snapshot* snapshot_;
} // namespace rocksdb