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/**
* Copyright (C) 2018-present MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* <http://www.mongodb.com/licensing/server-side-public-license>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the Server Side Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#pragma once
#include <boost/functional/hash.hpp>
#include <boost/optional.hpp>
#include <climits>
#include <cstdint>
#include <ostream>
#include "mongo/bson/util/builder.h"
#include "mongo/logger/logstream_builder.h"
#include "mongo/util/bufreader.h"
namespace mongo {
/**
* The key that uniquely identifies a Record in a Collection or RecordStore.
*/
class RecordId {
public:
// This set of constants define the boundaries of the 'normal' and 'reserved' id ranges.
static constexpr int64_t kNullRepr = 0;
static constexpr int64_t kMinRepr = LLONG_MIN;
static constexpr int64_t kMaxRepr = LLONG_MAX;
static constexpr int64_t kMinReservedRepr = kMaxRepr - (1024 * 1024);
/**
* Enumerates all ids in the reserved range that have been allocated for a specific purpose.
*/
enum class ReservedId : int64_t { kWildcardMultikeyMetadataId = kMinReservedRepr };
/**
* Constructs a Null RecordId.
*/
RecordId() : _repr(kNullRepr) {}
explicit RecordId(int64_t repr) : _repr(repr) {}
explicit RecordId(ReservedId repr) : RecordId(static_cast<int64_t>(repr)) {}
/**
* Construct a RecordId from two halves.
* TODO consider removing.
*/
RecordId(int high, int low) : _repr((uint64_t(high) << 32) | uint32_t(low)) {}
/**
* A RecordId that compares less than all ids that represent documents in a collection.
*/
static RecordId min() {
return RecordId(kMinRepr);
}
/**
* A RecordId that compares greater than all ids that represent documents in a collection.
*/
static RecordId max() {
return RecordId(kMaxRepr);
}
/**
* Returns the first record in the reserved id range at the top of the RecordId space.
*/
static RecordId minReserved() {
return RecordId(kMinReservedRepr);
}
bool isNull() const {
return _repr == 0;
}
int64_t repr() const {
return _repr;
}
/**
* Valid RecordIds are the only ones which may be used to represent Records. The range of valid
* RecordIds includes both "normal" ids that refer to user data, and "reserved" ids that are
* used internally. All RecordIds outside of the valid range are sentinel values.
*/
bool isValid() const {
return isNormal() || isReserved();
}
/**
* Normal RecordIds are those which fall within the range used to represent normal user data,
* excluding the reserved range at the top of the RecordId space.
*/
bool isNormal() const {
return _repr > 0 && _repr < kMinReservedRepr;
}
/**
* Returns true if this RecordId falls within the reserved range at the top of the record space.
*/
bool isReserved() const {
return _repr >= kMinReservedRepr && _repr < kMaxRepr;
}
int compare(RecordId rhs) const {
return _repr == rhs._repr ? 0 : _repr < rhs._repr ? -1 : 1;
}
/**
* Hash value for this RecordId. The hash implementation may be modified, and its behavior
* may differ across platforms. Hash values should not be persisted.
*/
struct Hasher {
size_t operator()(RecordId rid) const {
size_t hash = 0;
// TODO consider better hashes
boost::hash_combine(hash, rid.repr());
return hash;
}
};
/// members for Sorter
struct SorterDeserializeSettings {}; // unused
void serializeForSorter(BufBuilder& buf) const {
buf.appendNum(static_cast<long long>(_repr));
}
static RecordId deserializeForSorter(BufReader& buf, const SorterDeserializeSettings&) {
return RecordId(buf.read<LittleEndian<int64_t>>());
}
int memUsageForSorter() const {
return sizeof(RecordId);
}
RecordId getOwned() const {
return *this;
}
private:
int64_t _repr;
};
inline bool operator==(RecordId lhs, RecordId rhs) {
return lhs.repr() == rhs.repr();
}
inline bool operator!=(RecordId lhs, RecordId rhs) {
return lhs.repr() != rhs.repr();
}
inline bool operator<(RecordId lhs, RecordId rhs) {
return lhs.repr() < rhs.repr();
}
inline bool operator<=(RecordId lhs, RecordId rhs) {
return lhs.repr() <= rhs.repr();
}
inline bool operator>(RecordId lhs, RecordId rhs) {
return lhs.repr() > rhs.repr();
}
inline bool operator>=(RecordId lhs, RecordId rhs) {
return lhs.repr() >= rhs.repr();
}
inline StringBuilder& operator<<(StringBuilder& stream, const RecordId& id) {
return stream << "RecordId(" << id.repr() << ')';
}
inline std::ostream& operator<<(std::ostream& stream, const RecordId& id) {
return stream << "RecordId(" << id.repr() << ')';
}
inline std::ostream& operator<<(std::ostream& stream, const boost::optional<RecordId>& id) {
return stream << "RecordId(" << (id ? id.get().repr() : 0) << ')';
}
inline logger::LogstreamBuilder& operator<<(logger::LogstreamBuilder& stream, const RecordId& id) {
stream.stream() << id;
return stream;
}
} // namespace mongo
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