write_batch_base.h
// Copyright (c) 2015, Facebook, Inc. All rights reserved.
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree. An additional grant
// of patent rights can be found in the PATENTS file in the same directory.
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#pragma once
namespace rocksdb {
class Slice;
class Status;
class ColumnFamilyHandle;
class WriteBatch;
struct SliceParts;
// Abstract base class that defines the basic interface for a write batch.
// See WriteBatch for a basic implementation and WrithBatchWithIndex for an
// indexed implemenation.
class WriteBatchBase {
public:
virtual ~WriteBatchBase() {}
// Store the mapping "key->value" in the database.
virtual void Put(ColumnFamilyHandle* column_family, const Slice& key,
const Slice& value) = 0;
virtual void Put(const Slice& key, const Slice& value) = 0;
// Variant of Put() that gathers output like writev(2). The key and value
// that will be written to the database are concatentations of arrays of
// slices.
virtual void Put(ColumnFamilyHandle* column_family, const SliceParts& key,
const SliceParts& value);
virtual void Put(const SliceParts& key, const SliceParts& value);
// Merge "value" with the existing value of "key" in the database.
// "key->merge(existing, value)"
virtual void Merge(ColumnFamilyHandle* column_family, const Slice& key,
const Slice& value) = 0;
virtual void Merge(const Slice& key, const Slice& value) = 0;
// variant that takes SliceParts
virtual void Merge(ColumnFamilyHandle* column_family, const SliceParts& key,
const SliceParts& value);
virtual void Merge(const SliceParts& key, const SliceParts& value);
// If the database contains a mapping for "key", erase it. Else do nothing.
virtual void Delete(ColumnFamilyHandle* column_family, const Slice& key) = 0;
virtual void Delete(const Slice& key) = 0;
// variant that takes SliceParts
virtual void Delete(ColumnFamilyHandle* column_family, const SliceParts& key);
virtual void Delete(const SliceParts& key);
// Append a blob of arbitrary size to the records in this batch. The blob will
// be stored in the transaction log but not in any other file. In particular,
// it will not be persisted to the SST files. When iterating over this
// WriteBatch, WriteBatch::Handler::LogData will be called with the contents
// of the blob as it is encountered. Blobs, puts, deletes, and merges will be
// encountered in the same order in thich they were inserted. The blob will
// NOT consume sequence number(s) and will NOT increase the count of the batch
//
// Example application: add timestamps to the transaction log for use in
// replication.
virtual void PutLogData(const Slice& blob) = 0;
// Clear all updates buffered in this batch.
virtual void Clear() = 0;
// Covert this batch into a WriteBatch. This is an abstracted way of
// converting any WriteBatchBase(eg WriteBatchWithIndex) into a basic
// WriteBatch.
virtual WriteBatch* GetWriteBatch() = 0;
// Records the state of the batch for future calls to RollbackToSavePoint().
// May be called multiple times to set multiple save points.
virtual void SetSavePoint() = 0;
// Remove all entries in this batch (Put, Merge, Delete, PutLogData) since the
// most recent call to SetSavePoint() and removes the most recent save point.
// If there is no previous call to SetSavePoint(), behaves the same as
// Clear().
virtual Status RollbackToSavePoint() = 0;
};
} // namespace rocksdb