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/**
* Copyright (C) 2019-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.
*/
#include "mongo/platform/basic.h"
#include "mongo/db/query/count_command_as_aggregation_command.h"
#include "mongo/db/query/query_request.h"
#include "mongo/util/str.h"
namespace mongo {
namespace {
const char kQueryField[] = "query";
const char kLimitField[] = "limit";
const char kSkipField[] = "skip";
const char kHintField[] = "hint";
const char kCollationField[] = "collation";
const char kExplainField[] = "explain";
const char kCommentField[] = "comment";
const char kMaxTimeMSField[] = "maxTimeMS";
const char kReadConcernField[] = "readConcern";
} // namespace
StatusWith<BSONObj> countCommandAsAggregationCommand(const CountCommand& cmd,
const NamespaceString& nss) {
BSONObjBuilder aggregationBuilder;
aggregationBuilder.append("aggregate", nss.coll());
// Build an aggregation pipeline that performs the counting. We add stages that satisfy the
// query, skip and limit before finishing with the actual $count stage.
BSONArrayBuilder pipelineBuilder(aggregationBuilder.subarrayStart("pipeline"));
auto queryObj = cmd.getQuery();
if (!queryObj.isEmpty()) {
BSONObjBuilder matchBuilder(pipelineBuilder.subobjStart());
matchBuilder.append("$match", queryObj);
matchBuilder.doneFast();
}
if (auto skip = cmd.getSkip()) {
BSONObjBuilder skipBuilder(pipelineBuilder.subobjStart());
skipBuilder.append("$skip", skip.get());
skipBuilder.doneFast();
}
if (auto limit = cmd.getLimit()) {
BSONObjBuilder limitBuilder(pipelineBuilder.subobjStart());
limitBuilder.append("$limit", limit.get());
limitBuilder.doneFast();
}
BSONObjBuilder countBuilder(pipelineBuilder.subobjStart());
countBuilder.append("$count", "count");
countBuilder.doneFast();
pipelineBuilder.doneFast();
// Complete the command by appending the other options to the aggregate command.
if (auto collation = cmd.getCollation()) {
aggregationBuilder.append(kCollationField, collation.get());
}
aggregationBuilder.append(kHintField, cmd.getHint());
if (auto comment = cmd.getComment()) {
aggregationBuilder.append(kCommentField, comment.get());
}
if (auto maxTime = cmd.getMaxTimeMS()) {
if (maxTime.get() > 0) {
aggregationBuilder.append(kMaxTimeMSField, maxTime.get());
}
}
if (auto readConcern = cmd.getReadConcern()) {
if (!readConcern->isEmpty()) {
aggregationBuilder.append(kReadConcernField, readConcern.get());
}
}
if (auto unwrapped = cmd.getQueryOptions()) {
if (!unwrapped->isEmpty()) {
aggregationBuilder.append(QueryRequest::kUnwrappedReadPrefField, unwrapped.get());
}
}
// The 'cursor' option is always specified so that aggregation uses the cursor interface.
aggregationBuilder.append("cursor", BSONObj());
return aggregationBuilder.obj();
}
} // namespace mongo
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