1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
|
/**
* Copyright (c) 2011 10gen 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 <boost/intrusive_ptr.hpp>
#include <memory>
#include <string>
#include <vector>
#include "mongo/bson/bsonobj.h"
#include "mongo/db/namespace_string.h"
#include "mongo/db/operation_context.h"
#include "mongo/db/pipeline/aggregation_request.h"
#include "mongo/db/pipeline/document_comparator.h"
#include "mongo/db/pipeline/value_comparator.h"
#include "mongo/db/query/collation/collator_interface.h"
#include "mongo/util/intrusive_counter.h"
#include "mongo/util/string_map.h"
namespace mongo {
class ExpressionContext : public RefCountable {
public:
struct ResolvedNamespace {
ResolvedNamespace() = default;
ResolvedNamespace(NamespaceString ns, std::vector<BSONObj> pipeline);
NamespaceString ns;
std::vector<BSONObj> pipeline;
};
/**
* Constructs an ExpressionContext to be used for Pipeline parsing and evaluation.
* 'resolvedNamespaces' maps collection names (not full namespaces) to ResolvedNamespaces.
*/
ExpressionContext(OperationContext* opCtx,
const AggregationRequest& request,
std::unique_ptr<CollatorInterface> collator,
StringMap<ExpressionContext::ResolvedNamespace> resolvedNamespaces);
/**
* Used by a pipeline to check for interrupts so that killOp() works. Throws a UserAssertion if
* this aggregation pipeline has been interrupted.
*/
void checkForInterrupt();
const CollatorInterface* getCollator() const {
return _collator.get();
}
const DocumentComparator& getDocumentComparator() const {
return _documentComparator;
}
const ValueComparator& getValueComparator() const {
return _valueComparator;
}
/**
* Returns an ExpressionContext that is identical to 'this' that can be used to execute a
* separate aggregation pipeline on 'ns'.
*/
boost::intrusive_ptr<ExpressionContext> copyWith(NamespaceString ns) const;
/**
* Returns the ResolvedNamespace corresponding to 'nss'. It is an error to call this method on a
* namespace not involved in the pipeline.
*/
const ResolvedNamespace& getResolvedNamespace(const NamespaceString& nss) const {
auto it = _resolvedNamespaces.find(nss.coll());
invariant(it != _resolvedNamespaces.end());
return it->second;
};
bool isExplain = false;
bool inShard = false;
bool inRouter = false;
bool extSortAllowed = false;
bool bypassDocumentValidation = false;
NamespaceString ns;
std::string tempDir; // Defaults to empty to prevent external sorting in mongos.
OperationContext* opCtx;
// Collation requested by the user for this pipeline. Empty if the user did not request a
// collation.
BSONObj collation;
protected:
static const int kInterruptCheckPeriod = 128;
/**
* Should only be used by 'ExpressionContextForTest'.
*/
ExpressionContext() = default;
/**
* Sets '_collator' and resets '_documentComparator' and '_valueComparator'.
*
* Use with caution - it is illegal to change the collation once a Pipeline has been parsed with
* this ExpressionContext.
*/
void setCollator(std::unique_ptr<CollatorInterface> collator);
// Collator used for comparisons.
std::unique_ptr<CollatorInterface> _collator;
// Used for all comparisons of Document/Value during execution of the aggregation operation.
// Must not be changed after parsing a Pipeline with this ExpressionContext.
DocumentComparator _documentComparator;
ValueComparator _valueComparator;
// A map from namespace to the resolved namespace, in case any views are involved.
StringMap<ResolvedNamespace> _resolvedNamespaces;
int _interruptCounter = kInterruptCheckPeriod;
};
} // namespace mongo
|
