作者: 谢瑞阳 10225101483 徐翔宇 10225101535
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// 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.
#ifndef STORAGE_LEVELDB_DB_WRITE_BATCH_INTERNAL_H_
#define STORAGE_LEVELDB_DB_WRITE_BATCH_INTERNAL_H_
#include "leveldb/write_batch.h"
namespace leveldb {
// WriteBatchInternal provides static methods for manipulating a
// WriteBatch that we don't want in the public WriteBatch interface.
class WriteBatchInternal {
public:
static void PutLargeValueRef(WriteBatch* batch,
const Slice& key,
const LargeValueRef& large_ref);
// Return the number of entries in the batch.
static int Count(const WriteBatch* batch);
// Set the count for the number of entries in the batch.
static void SetCount(WriteBatch* batch, int n);
// Return the seqeunce number for the start of this batch.
static SequenceNumber Sequence(const WriteBatch* batch);
// Store the specified number as the seqeunce number for the start of
// this batch.
static void SetSequence(WriteBatch* batch, SequenceNumber seq);
static Slice Contents(const WriteBatch* batch) {
return Slice(batch->rep_);
}
static size_t ByteSize(const WriteBatch* batch) {
return batch->rep_.size();
}
static void SetContents(WriteBatch* batch, const Slice& contents);
static Status InsertInto(const WriteBatch* batch, MemTable* memtable);
// Iterate over the contents of a write batch.
class Iterator {
public:
explicit Iterator(const WriteBatch& batch);
bool Done() const { return done_; }
void Next();
ValueType op() const { return op_; }
const Slice& key() const { return key_; }
const Slice& value() const { return value_; }
SequenceNumber sequence_number() const { return seq_; }
Status status() const { return status_; }
private:
void GetNextEntry();
Slice input_;
bool done_;
ValueType op_;
Slice key_;
Slice value_;
SequenceNumber seq_;
Status status_;
};
};
}
#endif // STORAGE_LEVELDB_DB_WRITE_BATCH_INTERNAL_H_