rocksdb/db/snapshot_checker.h
sdong fdf882ded2 Replace namespace name "rocksdb" with ROCKSDB_NAMESPACE (#6433)
Summary:
When dynamically linking two binaries together, different builds of RocksDB from two sources might cause errors. To provide a tool for user to solve the problem, the RocksDB namespace is changed to a flag which can be overridden in build time.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6433

Test Plan: Build release, all and jtest. Try to build with ROCKSDB_NAMESPACE with another flag.

Differential Revision: D19977691

fbshipit-source-id: aa7f2d0972e1c31d75339ac48478f34f6cfcfb3e
2020-02-20 12:09:57 -08:00

62 lines
1.9 KiB
C++

// 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 {
enum class SnapshotCheckerResult : int {
kInSnapshot = 0,
kNotInSnapshot = 1,
// In case snapshot is released and the checker has no clue whether
// the given sequence is visible to the snapshot.
kSnapshotReleased = 2,
};
// Callback class that control GC of duplicate keys in flush/compaction.
class SnapshotChecker {
public:
virtual ~SnapshotChecker() {}
virtual SnapshotCheckerResult CheckInSnapshot(
SequenceNumber sequence, SequenceNumber snapshot_sequence) const = 0;
};
class DisableGCSnapshotChecker : public SnapshotChecker {
public:
virtual ~DisableGCSnapshotChecker() {}
virtual SnapshotCheckerResult CheckInSnapshot(
SequenceNumber /*sequence*/,
SequenceNumber /*snapshot_sequence*/) const override {
// By returning kNotInSnapshot, we prevent all the values from being GCed
return SnapshotCheckerResult::kNotInSnapshot;
}
static DisableGCSnapshotChecker* Instance() { return &instance_; }
protected:
static DisableGCSnapshotChecker instance_;
explicit DisableGCSnapshotChecker() {}
};
class WritePreparedTxnDB;
// Callback class created by WritePreparedTxnDB to check if a key
// is visible by a snapshot.
class WritePreparedSnapshotChecker : public SnapshotChecker {
public:
explicit WritePreparedSnapshotChecker(WritePreparedTxnDB* txn_db);
virtual ~WritePreparedSnapshotChecker() {}
virtual SnapshotCheckerResult CheckInSnapshot(
SequenceNumber sequence, SequenceNumber snapshot_sequence) const override;
private:
#ifndef ROCKSDB_LITE
const WritePreparedTxnDB* const txn_db_;
#endif // !ROCKSDB_LITE
};
} // namespace ROCKSDB_NAMESPACE