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
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
|
/**
* Copyright (C) 2020-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 <algorithm>
#include <boost/intrusive_ptr.hpp>
#include <boost/optional.hpp>
#include <iterator>
#include "mongo/base/string_data.h"
#include "mongo/bson/bsonmisc.h"
#include "mongo/db/cst/c_node.h"
#include "mongo/db/cst/cst_match_translation.h"
#include "mongo/db/cst/cst_pipeline_translation.h"
#include "mongo/db/cst/key_fieldname.h"
#include "mongo/db/cst/key_value.h"
#include "mongo/db/matcher/expression_expr.h"
#include "mongo/db/matcher/expression_tree.h"
#include "mongo/db/matcher/matcher_type_set.h"
#include "mongo/util/visit_helper.h"
namespace mongo::cst_match_translation {
namespace {
std::unique_ptr<MatchExpression> translateMatchPredicate(
const CNode::Fieldname& fieldName,
const CNode& cst,
const boost::intrusive_ptr<ExpressionContext>& expCtx,
const ExtensionsCallback& extensionsCallback);
std::unique_ptr<MatchExpression> translatePathExpression(const UserFieldname& fieldName,
const CNode::ObjectChildren& object);
/**
* Walk an array of nodes and produce a vector of MatchExpressions.
*/
template <class Type>
std::unique_ptr<Type> translateTreeExpr(const CNode::ArrayChildren& array,
const boost::intrusive_ptr<ExpressionContext>& expCtx,
const ExtensionsCallback& extensionsCallback) {
auto expr = std::make_unique<Type>();
for (auto&& node : array) {
// Tree expressions require each element to be it's own match expression object.
expr->add(translateMatchExpression(node, expCtx, extensionsCallback));
}
return expr;
}
// Handles predicates of the form <fieldname>: { $not: <argument> }
std::unique_ptr<MatchExpression> translateNot(const UserFieldname& fieldName,
const CNode& argument) {
// $not can accept a regex or an object expression.
if (auto regex = stdx::get_if<UserRegex>(&argument.payload)) {
auto regexExpr =
std::make_unique<RegexMatchExpression>(fieldName, regex->pattern, regex->flags);
return std::make_unique<NotMatchExpression>(std::move(regexExpr));
}
auto root = std::make_unique<AndMatchExpression>();
root->add(
translatePathExpression(fieldName, stdx::get<CNode::ObjectChildren>(argument.payload)));
return std::make_unique<NotMatchExpression>(std::move(root));
}
std::unique_ptr<MatchExpression> translateExists(const CNode::Fieldname& fieldName,
const CNode& argument) {
auto root = std::make_unique<ExistsMatchExpression>(stdx::get<UserFieldname>(fieldName));
if (stdx::visit(
visit_helper::Overloaded{
[&](const UserLong& userLong) { return userLong != 0; },
[&](const UserDouble& userDbl) { return userDbl != 0; },
[&](const UserDecimal& userDc) { return userDc.isNotEqual(Decimal128(0)); },
[&](const UserInt& userInt) { return userInt != 0; },
[&](const UserBoolean& b) { return b; },
[&](const UserNull&) { return false; },
[&](const UserUndefined&) { return false; },
[&](auto&&) { return true; }},
argument.payload)) {
return root;
}
return std::make_unique<NotMatchExpression>(root.release());
}
MatcherTypeSet getMatcherTypeSet(const CNode& argument) {
MatcherTypeSet ts;
auto add_individual_to_type_set = [&](const CNode& a) {
return stdx::visit(
visit_helper::Overloaded{
[&](const UserLong& userLong) {
auto valueAsInt =
BSON("" << userLong).firstElement().parseIntegerElementToInt();
ts.bsonTypes.insert(static_cast<BSONType>(valueAsInt.getValue()));
},
[&](const UserDouble& userDbl) {
auto valueAsInt = BSON("" << userDbl).firstElement().parseIntegerElementToInt();
ts.bsonTypes.insert(static_cast<BSONType>(valueAsInt.getValue()));
},
[&](const UserDecimal& userDc) {
auto valueAsInt = BSON("" << userDc).firstElement().parseIntegerElementToInt();
ts.bsonTypes.insert(static_cast<BSONType>(valueAsInt.getValue()));
},
[&](const UserInt& userInt) {
auto valueAsInt = BSON("" << userInt).firstElement().parseIntegerElementToInt();
ts.bsonTypes.insert(static_cast<BSONType>(valueAsInt.getValue()));
},
[&](const UserString& s) {
if (StringData{s} == MatcherTypeSet::kMatchesAllNumbersAlias) {
ts.allNumbers = true;
return;
}
auto optValue = findBSONTypeAlias(s);
invariant(optValue);
ts.bsonTypes.insert(*optValue);
},
[&](auto&&) { MONGO_UNREACHABLE; }},
a.payload);
};
if (auto children = stdx::get_if<CNode::ArrayChildren>(&argument.payload)) {
for (auto child : (*children)) {
add_individual_to_type_set(child);
}
} else {
add_individual_to_type_set(argument);
}
return ts;
}
// Handles predicates of the form <fieldname>: { ... }
// For example:
// { abc: {$not: 5} }
// { abc: {$eq: 0} }
// { abc: {$gt: 0, $lt: 2} }
// Examples of predicates not handled here:
// { abc: 5 }
// { $expr: ... }
// { $where: "return 1" }
// Note, this function does not require an ExpressionContext.
// The only MatchExpression that requires an ExpressionContext is $expr
// (if you include $where, which can desugar to $expr + $function).
std::unique_ptr<MatchExpression> translatePathExpression(const UserFieldname& fieldName,
const CNode::ObjectChildren& object) {
for (auto&& [op, argument] : object) {
switch (stdx::get<KeyFieldname>(op)) {
case KeyFieldname::notExpr:
return translateNot(fieldName, argument);
case KeyFieldname::existsExpr:
return translateExists(fieldName, argument);
case KeyFieldname::type:
return std::make_unique<TypeMatchExpression>(fieldName,
getMatcherTypeSet(argument));
case KeyFieldname::matchMod: {
const auto divisor =
stdx::get<CNode::ArrayChildren>(argument.payload)[0].numberInt();
const auto remainder =
stdx::get<CNode::ArrayChildren>(argument.payload)[1].numberInt();
return std::make_unique<ModMatchExpression>(fieldName, divisor, remainder);
}
default:
MONGO_UNREACHABLE;
}
}
MONGO_UNREACHABLE;
}
// Take a variant and either get (by copying) the T it holds, or construct a default value using
// the callable. For example:
// getOr<int>(123, []() { return 0; }) == 123
// getOr<int>("x", []() { return 0; }) == 0
template <class T, class V, class F>
T getOr(const V& myVariant, F makeDefaultValue) {
if (auto* value = stdx::get_if<T>(&myVariant)) {
return *value;
} else {
return makeDefaultValue();
}
}
// Handles predicates of the form <fieldname>: <anything>
// For example:
// { abc: 5 }
// { abc: {$lt: 5} }
// Examples of predicates not handled here:
// { $where: "return 1" }
// { $and: ... }
std::unique_ptr<MatchExpression> translateMatchPredicate(
const CNode::Fieldname& fieldName,
const CNode& cst,
const boost::intrusive_ptr<ExpressionContext>& expCtx,
const ExtensionsCallback& extensionsCallback) {
if (auto keyField = stdx::get_if<KeyFieldname>(&fieldName)) {
// Top level match expression.
switch (*keyField) {
case KeyFieldname::andExpr:
return translateTreeExpr<AndMatchExpression>(
cst.arrayChildren(), expCtx, extensionsCallback);
case KeyFieldname::orExpr:
return translateTreeExpr<OrMatchExpression>(
cst.arrayChildren(), expCtx, extensionsCallback);
case KeyFieldname::norExpr:
return translateTreeExpr<NorMatchExpression>(
cst.arrayChildren(), expCtx, extensionsCallback);
case KeyFieldname::commentExpr:
// comment expr is not added to the tree.
return nullptr;
case KeyFieldname::expr: {
// The ExprMatchExpression maintains (shared) ownership of expCtx,
// which the Expression from translateExpression depends on.
return std::make_unique<ExprMatchExpression>(
cst_pipeline_translation::translateExpression(
cst, expCtx.get(), expCtx->variablesParseState),
expCtx);
}
case KeyFieldname::text: {
const auto& args = cst.objectChildren();
dassert(verifyFieldnames(
{
KeyFieldname::caseSensitive,
KeyFieldname::diacriticSensitive,
KeyFieldname::language,
KeyFieldname::search,
},
args));
TextMatchExpressionBase::TextParams params;
params.caseSensitive = getOr<bool>(args[0].second.payload, []() {
return TextMatchExpressionBase::kCaseSensitiveDefault;
});
params.diacriticSensitive = getOr<bool>(args[1].second.payload, []() {
return TextMatchExpressionBase::kDiacriticSensitiveDefault;
});
params.language = getOr<std::string>(args[2].second.payload, []() { return ""s; });
params.query = stdx::get<std::string>(args[3].second.payload);
return extensionsCallback.createText(std::move(params));
}
case KeyFieldname::where: {
std::string code;
if (auto str = stdx::get_if<UserString>(&cst.payload)) {
code = *str;
} else if (auto js = stdx::get_if<UserJavascript>(&cst.payload)) {
code = std::string{js->code};
} else {
MONGO_UNREACHABLE;
}
return extensionsCallback.createWhere(expCtx, {std::move(code)});
}
default:
MONGO_UNREACHABLE;
}
} else {
// Expression is over a user fieldname.
return stdx::visit(
visit_helper::Overloaded{
[&](const CNode::ObjectChildren& userObject) -> std::unique_ptr<MatchExpression> {
return translatePathExpression(stdx::get<UserFieldname>(fieldName), userObject);
},
[&](const CNode::ArrayChildren& userObject) -> std::unique_ptr<MatchExpression> {
MONGO_UNREACHABLE;
},
// Other types are always treated as equality predicates.
[&](auto&& userValue) -> std::unique_ptr<MatchExpression> {
return std::make_unique<EqualityMatchExpression>(
StringData{stdx::get<UserFieldname>(fieldName)},
cst_pipeline_translation::translateLiteralLeaf(cst),
nullptr, /* TODO SERVER-49486: Add ErrorAnnotation for MatchExpressions */
expCtx->getCollator());
}},
cst.payload);
}
MONGO_UNREACHABLE;
}
} // namespace
std::unique_ptr<MatchExpression> translateMatchExpression(
const CNode& cst,
const boost::intrusive_ptr<ExpressionContext>& expCtx,
const ExtensionsCallback& extensionsCallback) {
auto root = std::make_unique<AndMatchExpression>();
for (const auto& [fieldName, expr] : cst.objectChildren()) {
// A nullptr for 'translatedExpression' indicates that the particular operator should not
// be added to 'root'. The $comment operator currently follows this convention.
if (auto translatedExpression =
translateMatchPredicate(fieldName, expr, expCtx, extensionsCallback);
translatedExpression) {
root->add(std::move(translatedExpression));
}
}
return root;
}
bool verifyFieldnames(const std::vector<CNode::Fieldname>& expected,
const std::vector<std::pair<CNode::Fieldname, CNode>>& actual) {
if (expected.size() != actual.size())
return false;
for (size_t i = 0; i < expected.size(); ++i) {
if (expected[i] != actual[i].first)
return false;
}
return true;
}
} // namespace mongo::cst_match_translation
|