1
2 /**
3 * Copyright (C) 2018-present MongoDB, Inc.
4 *
5 * This program is free software: you can redistribute it and/or modify
6 * it under the terms of the Server Side Public License, version 1,
7 * as published by MongoDB, Inc.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * Server Side Public License for more details.
13 *
14 * You should have received a copy of the Server Side Public License
15 * along with this program. If not, see
16 * <http://www.mongodb.com/licensing/server-side-public-license>.
17 *
18 * As a special exception, the copyright holders give permission to link the
19 * code of portions of this program with the OpenSSL library under certain
20 * conditions as described in each individual source file and distribute
21 * linked combinations including the program with the OpenSSL library. You
22 * must comply with the Server Side Public License in all respects for
23 * all of the code used other than as permitted herein. If you modify file(s)
24 * with this exception, you may extend this exception to your version of the
25 * file(s), but you are not obligated to do so. If you do not wish to do so,
26 * delete this exception statement from your version. If you delete this
27 * exception statement from all source files in the program, then also delete
28 * it in the license file.
29 */
30
31 #include "mongo/platform/basic.h"
32
33 #include "mongo/db/exec/pipeline_proxy.h"
34
35
36 #include "mongo/db/pipeline/document_source.h"
37 #include "mongo/db/pipeline/expression_context.h"
38 #include "mongo/db/pipeline/pipeline_d.h"
39 #include "mongo/stdx/memory.h"
40
41 namespace mongo {
42
43 using boost::intrusive_ptr;
44 using std::shared_ptr;
45 using std::unique_ptr;
46 using std::vector;
47 using stdx::make_unique;
48
49 const char* PipelineProxyStage::kStageType = "PIPELINE_PROXY";
50
PipelineProxyStage(OperationContext * opCtx,std::unique_ptr<Pipeline,Pipeline::Deleter> pipeline,WorkingSet * ws)51 PipelineProxyStage::PipelineProxyStage(OperationContext* opCtx,
52 std::unique_ptr<Pipeline, Pipeline::Deleter> pipeline,
53 WorkingSet* ws)
54 : PlanStage(kStageType, opCtx),
55 _pipeline(std::move(pipeline)),
56 _includeMetaData(_pipeline->getContext()->needsMerge), // send metadata to merger
57 _includeSortKey(_includeMetaData && !_pipeline->getContext()->from34Mongos),
58 _ws(ws) {
59 // We take over responsibility for disposing of the Pipeline, since it is required that
60 // doDispose() will be called before destruction of this PipelineProxyStage.
61 _pipeline.get_deleter().dismissDisposal();
62 }
63
doWork(WorkingSetID * out)64 PlanStage::StageState PipelineProxyStage::doWork(WorkingSetID* out) {
65 if (!out) {
66 return PlanStage::FAILURE;
67 }
68
69 if (!_stash.empty()) {
70 *out = _ws->allocate();
71 WorkingSetMember* member = _ws->get(*out);
72 member->obj = Snapshotted<BSONObj>(SnapshotId(), _stash.back());
73 _stash.pop_back();
74 member->transitionToOwnedObj();
75 return PlanStage::ADVANCED;
76 }
77
78 if (boost::optional<BSONObj> next = getNextBson()) {
79 *out = _ws->allocate();
80 WorkingSetMember* member = _ws->get(*out);
81 member->obj = Snapshotted<BSONObj>(SnapshotId(), *next);
82 member->transitionToOwnedObj();
83 return PlanStage::ADVANCED;
84 }
85
86 return PlanStage::IS_EOF;
87 }
88
isEOF()89 bool PipelineProxyStage::isEOF() {
90 if (!_stash.empty())
91 return false;
92
93 if (boost::optional<BSONObj> next = getNextBson()) {
94 _stash.push_back(*next);
95 return false;
96 }
97
98 return true;
99 }
100
doDetachFromOperationContext()101 void PipelineProxyStage::doDetachFromOperationContext() {
102 _pipeline->detachFromOperationContext();
103 }
104
doReattachToOperationContext()105 void PipelineProxyStage::doReattachToOperationContext() {
106 _pipeline->reattachToOperationContext(getOpCtx());
107 }
108
doDispose()109 void PipelineProxyStage::doDispose() {
110 _pipeline->dispose(getOpCtx());
111 }
112
getStats()113 unique_ptr<PlanStageStats> PipelineProxyStage::getStats() {
114 unique_ptr<PlanStageStats> ret =
115 make_unique<PlanStageStats>(CommonStats(kStageType), STAGE_PIPELINE_PROXY);
116 ret->specific = make_unique<CollectionScanStats>();
117 return ret;
118 }
119
getNextBson()120 boost::optional<BSONObj> PipelineProxyStage::getNextBson() {
121 if (auto next = _pipeline->getNext()) {
122 if (_includeMetaData) {
123 return next->toBsonWithMetaData(_includeSortKey);
124 } else {
125 return next->toBson();
126 }
127 }
128
129 return boost::none;
130 }
131
getLatestOplogTimestamp() const132 Timestamp PipelineProxyStage::getLatestOplogTimestamp() const {
133 return PipelineD::getLatestOplogTimestamp(_pipeline.get());
134 }
135
getPlanSummaryStr() const136 std::string PipelineProxyStage::getPlanSummaryStr() const {
137 return PipelineD::getPlanSummaryStr(_pipeline.get());
138 }
139
getPlanSummaryStats(PlanSummaryStats * statsOut) const140 void PipelineProxyStage::getPlanSummaryStats(PlanSummaryStats* statsOut) const {
141 invariant(statsOut);
142 PipelineD::getPlanSummaryStats(_pipeline.get(), statsOut);
143 statsOut->nReturned = getCommonStats()->advanced;
144 }
145 } // namespace mongo
146