fork of https://github.com/oxigraph/rocksdb and https://github.com/facebook/rocksdb for nextgraph and oxigraph
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
66 lines
2.0 KiB
66 lines
2.0 KiB
// 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).
|
|
//
|
|
// 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
|
|
#include <string>
|
|
#include <utility>
|
|
#include "rocksdb/db.h"
|
|
#include "rocksdb/slice.h"
|
|
#include "rocksdb/types.h"
|
|
|
|
namespace ROCKSDB_NAMESPACE {
|
|
|
|
// A helper class useful for DBImpl::Get()
|
|
class LookupKey {
|
|
public:
|
|
// Initialize *this for looking up user_key at a snapshot with
|
|
// the specified sequence number.
|
|
LookupKey(const Slice& _user_key, SequenceNumber sequence,
|
|
const Slice* ts = nullptr);
|
|
|
|
~LookupKey();
|
|
|
|
// Return a key suitable for lookup in a MemTable.
|
|
Slice memtable_key() const {
|
|
return Slice(start_, static_cast<size_t>(end_ - start_));
|
|
}
|
|
|
|
// Return an internal key (suitable for passing to an internal iterator)
|
|
Slice internal_key() const {
|
|
return Slice(kstart_, static_cast<size_t>(end_ - kstart_));
|
|
}
|
|
|
|
// Return the user key
|
|
Slice user_key() const {
|
|
return Slice(kstart_, static_cast<size_t>(end_ - kstart_ - 8));
|
|
}
|
|
|
|
private:
|
|
// We construct a char array of the form:
|
|
// klength varint32 <-- start_
|
|
// userkey char[klength] <-- kstart_
|
|
// tag uint64
|
|
// <-- end_
|
|
// The array is a suitable MemTable key.
|
|
// The suffix starting with "userkey" can be used as an InternalKey.
|
|
const char* start_;
|
|
const char* kstart_;
|
|
const char* end_;
|
|
char space_[200]; // Avoid allocation for short keys
|
|
|
|
// No copying allowed
|
|
LookupKey(const LookupKey&);
|
|
void operator=(const LookupKey&);
|
|
};
|
|
|
|
inline LookupKey::~LookupKey() {
|
|
if (start_ != space_) delete[] start_;
|
|
}
|
|
|
|
} // namespace ROCKSDB_NAMESPACE
|
|
|