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/**
* Copyright (C) 2015 MongoDB Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* 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
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* 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 GNU Affero General 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 <vector>
#include "mongo/base/disallow_copying.h"
#include "mongo/base/status_with.h"
#include "mongo/bson/bsonobj.h"
#include "mongo/db/clientcursor.h"
#include "mongo/db/namespace_string.h"
namespace mongo {
/**
* Builds the cursor field for a reply to a cursor-generating command in place.
*/
class CursorResponseBuilder {
MONGO_DISALLOW_COPYING(CursorResponseBuilder);
public:
/**
* Once constructed, you may not use the passed-in BSONObjBuilder until you call either done()
* or abandon(), or this object goes out of scope. This is the same as the rule when using a
* BSONObjBuilder to build a sub-object with subobjStart().
*
* If the builder goes out of scope without a call to done(), any data appended to the
* builder will be removed.
*/
CursorResponseBuilder(bool isInitialResponse, BSONObjBuilder* commandResponse);
~CursorResponseBuilder() {
if (_active)
abandon();
}
size_t bytesUsed() const {
invariant(_active);
return _batch.len();
}
void append(const BSONObj& obj) {
invariant(_active);
_batch.append(obj);
}
/**
* Call this after successfully appending all fields that will be part of this response.
* After calling, you may not call any more methods on this object.
*/
void done(CursorId cursorId, StringData cursorNamespace);
/**
* Call this if the response should not contain cursor information. It will completely remove
* the cursor field from the commandResponse, as if the CursorResponseBuilder was never used.
* After calling, you may not call any more methods on this object.
*/
void abandon();
private:
const int _responseInitialLen; // Must be the first member so its initializer runs first.
bool _active = true;
BSONObjBuilder* const _commandResponse;
BSONObjBuilder _cursorObject;
BSONArrayBuilder _batch;
};
/**
* Builds a cursor response object from the provided cursor identifiers and "firstBatch",
* and appends the response object to the provided builder under the field name "cursor".
*
* The response object has the following format:
* { id: <NumberLong>, ns: <String>, firstBatch: <Array> }.
*
* This function is deprecated. Prefer CursorResponseBuilder or CursorResponse::toBSON() instead.
*/
void appendCursorResponseObject(long long cursorId,
StringData cursorNamespace,
BSONArray firstBatch,
BSONObjBuilder* builder);
/**
* Builds a getMore response object from the provided cursor identifiers and "nextBatch",
* and appends the response object to the provided builder under the field name "cursor".
*
* The response object has the following format:
* { id: <NumberLong>, ns: <String>, nextBatch: <Array> }.
*
* This function is deprecated. Prefer CursorResponseBuilder or CursorResponse::toBSON() instead.
*/
void appendGetMoreResponseObject(long long cursorId,
StringData cursorNamespace,
BSONArray nextBatch,
BSONObjBuilder* builder);
class CursorResponse {
MONGO_DISALLOW_COPYING(CursorResponse);
public:
enum class ResponseType {
InitialResponse,
SubsequentResponse,
};
/**
* Constructs from values for each of the fields.
*/
CursorResponse(NamespaceString nss,
CursorId cursorId,
std::vector<BSONObj> batch,
boost::optional<long long> numReturnedSoFar = boost::none);
CursorResponse(CursorResponse&& other) = default;
CursorResponse& operator=(CursorResponse&& other) = default;
//
// Accessors.
//
const NamespaceString& getNSS() const {
return _nss;
}
CursorId getCursorId() const {
return _cursorId;
}
const std::vector<BSONObj>& getBatch() const {
return _batch;
}
boost::optional<long long> getNumReturnedSoFar() const {
return _numReturnedSoFar;
}
/**
* Constructs a CursorResponse from the command BSON response.
*/
static StatusWith<CursorResponse> parseFromBSON(const BSONObj& cmdResponse);
/**
* Converts this response to its raw BSON representation.
*/
BSONObj toBSON(ResponseType responseType) const;
void addToBSON(ResponseType responseType, BSONObjBuilder* builder) const;
private:
NamespaceString _nss;
CursorId _cursorId;
std::vector<BSONObj> _batch;
boost::optional<long long> _numReturnedSoFar;
};
} // namespace mongo
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