rocksdb/db/snapshot_checker.h
mrambacher b11ff347b4 Use STATIC_AVOID_DESTRUCTION for static objects with non-trivial destructors (#9958)
Summary:
Changed the static objects that had non-trivial destructors to use the STATIC_AVOID_DESTRUCTION construct.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9958

Reviewed By: pdillinger

Differential Revision: D36442982

Pulled By: mrambacher

fbshipit-source-id: 029d47b1374d30d198bfede369a4c0ae7a4eb519
2022-05-17 09:39:22 -07:00

61 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();
protected:
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