rocksdb/db/memtable.h
jorlow@chromium.org f67e15e50f Initial checkin.
git-svn-id: https://leveldb.googlecode.com/svn/trunk@2 62dab493-f737-651d-591e-8d6aee1b9529
2011-03-18 22:37:00 +00:00

70 lines
2.0 KiB
C++

// 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_MEMTABLE_H_
#define STORAGE_LEVELDB_DB_MEMTABLE_H_
#include <string>
#include "include/db.h"
#include "db/dbformat.h"
#include "db/skiplist.h"
#include "util/arena.h"
namespace leveldb {
class InternalKeyComparator;
class Mutex;
class MemTableIterator;
class MemTable {
public:
explicit MemTable(const InternalKeyComparator& comparator);
~MemTable();
// Returns an estimate of the number of bytes of data in use by this
// data structure.
//
// REQUIRES: external synchronization to prevent simultaneous
// operations on the same MemTable.
size_t ApproximateMemoryUsage();
// Return an iterator that yields the contents of the memtable.
//
// The caller must ensure that the underlying MemTable remains live
// while the returned iterator is live. The keys returned by this
// iterator are internal keys encoded by AppendInternalKey in the
// db/format.{h,cc} module.
Iterator* NewIterator();
// Add an entry into memtable that maps key to value at the
// specified sequence number and with the specified type.
// Typically value will be empty if type==kTypeDeletion.
void Add(SequenceNumber seq, ValueType type,
const Slice& key,
const Slice& value);
private:
struct KeyComparator {
const InternalKeyComparator comparator;
explicit KeyComparator(const InternalKeyComparator& c) : comparator(c) { }
int operator()(const char* a, const char* b) const;
};
friend class MemTableIterator;
friend class MemTableBackwardIterator;
typedef SkipList<const char*, KeyComparator> Table;
KeyComparator comparator_;
Arena arena_;
Table table_;
// No copying allowed
MemTable(const MemTable&);
void operator=(const MemTable&);
};
}
#endif // STORAGE_LEVELDB_DB_MEMTABLE_H_