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
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
|
// projection.h
/* Copyright 2009 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 "mongo/pch.h"
#include "mongo/util/string_map.h"
#include "mongo/db/jsobj.h"
#include "mongo/db/matcher/matcher.h"
namespace mongo {
/**
* given a document and a projection specification
* can transform the document
* currently supports specifying which fields and $slice
*/
class Projection {
public:
class KeyOnly {
public:
KeyOnly() : _stringSize(0) {}
BSONObj hydrate( const BSONObj& key ) const;
void addNo() { _add( false , "" ); }
void addYes( const std::string& name ) { _add( true , name ); }
private:
void _add( bool b , const std::string& name ) {
_include.push_back( b );
_names.push_back( name );
_stringSize += name.size();
}
std::vector<bool> _include; // one entry per field in key. true iff should be in output
std::vector<std::string> _names; // name of field since key doesn't have names
int _stringSize;
};
enum ArrayOpType {
ARRAY_OP_NORMAL = 0,
ARRAY_OP_ELEM_MATCH,
ARRAY_OP_POSITIONAL
};
Projection() :
_include(true) ,
_special(false) ,
_includeID(true) ,
_skip(0) ,
_limit(-1) ,
_arrayOpType(ARRAY_OP_NORMAL),
_hasNonSimple(false) {
}
/**
* called once per lifetime
* e.g. { "x" : 1 , "a.y" : 1 }
*/
void init(const BSONObj& spec, const MatchExpressionParser::WhereCallback& whereCallback);
/**
* @return the spec init was called with
*/
BSONObj getSpec() const { return _source; }
/**
* transforms in according to spec
*/
BSONObj transform( const BSONObj& in, const MatchDetails* details = NULL ) const;
/**
* transforms in according to spec
*/
void transform( const BSONObj& in , BSONObjBuilder& b, const MatchDetails* details = NULL ) const;
/**
* @return if the keyPattern has all the information needed to return then
* return a new KeyOnly otherwise null
* NOTE: a key may have modified the actual data
* which has to be handled above this (arrays, geo)
*/
KeyOnly* checkKey( const BSONObj& keyPattern ) const;
bool includeID() const { return _includeID; }
/**
* get the type of array operator for the projection
* @return ARRAY_OP_NORMAL if no array projection modifier,
* ARRAY_OP_ELEM_MATCH if one or more $elemMatch specifier,
* ARRAY_OP_POSITIONAL if one '.$' projection specified
*/
ArrayOpType getArrayOpType() const;
/**
* Validate the given query satisfies this projection's positional operator.
* NOTE: this function is only used to validate projections with a positional operator.
* @param query User-supplied query specifier
* @return Field name if found, empty std::string otherwise.
*/
void validateQuery( const BSONObj query ) const;
private:
/**
* appends e to b if user wants it
* will descend into e if needed
*/
void append( BSONObjBuilder& b , const BSONElement& e, const MatchDetails* details = NULL,
const ArrayOpType arrayOpType = ARRAY_OP_NORMAL ) const;
void add( const std::string& field, bool include );
void add( const std::string& field, int skip, int limit );
void appendArray( BSONObjBuilder& b , const BSONObj& a , bool nested=false) const;
bool _include; // true if default at this level is to include
bool _special; // true if this level can't be skipped or included without recursing
//TODO: benchmark std::vector<pair> vs map
typedef StringMap<boost::shared_ptr<Projection> > FieldMap;
FieldMap _fields;
BSONObj _source;
bool _includeID;
// used for $slice operator
int _skip;
int _limit;
// used for $elemMatch and positional operator ($)
typedef StringMap<boost::shared_ptr<Matcher> > Matchers;
Matchers _matchers;
ArrayOpType _arrayOpType;
bool _hasNonSimple;
};
}
|
