-
Notifications
You must be signed in to change notification settings - Fork 1.2k
/
DistinctOperation.cs
288 lines (257 loc) · 10.2 KB
/
DistinctOperation.cs
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
/* Copyright 2013-present MongoDB Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
using System;
using System.Threading;
using System.Threading.Tasks;
using MongoDB.Bson;
using MongoDB.Bson.IO;
using MongoDB.Bson.Serialization;
using MongoDB.Bson.Serialization.Serializers;
using MongoDB.Driver.Core.Bindings;
using MongoDB.Driver.Core.Connections;
using MongoDB.Driver.Core.Events;
using MongoDB.Driver.Core.Misc;
using MongoDB.Driver.Core.WireProtocol.Messages.Encoders;
namespace MongoDB.Driver.Core.Operations
{
/// <summary>
/// Represents a distinct operation.
/// </summary>
/// <typeparam name="TValue">The type of the value.</typeparam>
public class DistinctOperation<TValue> : IReadOperation<IAsyncCursor<TValue>>
{
// fields
private Collation _collation;
private CollectionNamespace _collectionNamespace;
private BsonValue _comment;
private BsonDocument _filter;
private string _fieldName;
private TimeSpan? _maxTime;
private MessageEncoderSettings _messageEncoderSettings;
private ReadConcern _readConcern = ReadConcern.Default;
private bool _retryRequested;
private IBsonSerializer<TValue> _valueSerializer;
// constructors
/// <summary>
/// Initializes a new instance of the <see cref="DistinctOperation{TValue}"/> class.
/// </summary>
/// <param name="collectionNamespace">The collection namespace.</param>
/// <param name="valueSerializer">The value serializer.</param>
/// <param name="fieldName">The name of the field.</param>
/// <param name="messageEncoderSettings">The message encoder settings.</param>
public DistinctOperation(CollectionNamespace collectionNamespace, IBsonSerializer<TValue> valueSerializer, string fieldName, MessageEncoderSettings messageEncoderSettings)
{
_collectionNamespace = Ensure.IsNotNull(collectionNamespace, nameof(collectionNamespace));
_valueSerializer = Ensure.IsNotNull(valueSerializer, nameof(valueSerializer));
_fieldName = Ensure.IsNotNullOrEmpty(fieldName, nameof(fieldName));
_messageEncoderSettings = Ensure.IsNotNull(messageEncoderSettings, nameof(messageEncoderSettings));
}
// properties
/// <summary>
/// Gets or sets the collation.
/// </summary>
/// <value>
/// The collation.
/// </value>
public Collation Collation
{
get { return _collation; }
set { _collation = value; }
}
/// <summary>
/// Gets or sets the comment.
/// </summary>
/// <value>
/// The comment.
/// </value>
public BsonValue Comment
{
get { return _comment; }
set { _comment = value; }
}
/// <summary>
/// Gets the collection namespace.
/// </summary>
/// <value>
/// The collection namespace.
/// </value>
public CollectionNamespace CollectionNamespace
{
get { return _collectionNamespace; }
}
/// <summary>
/// Gets or sets the filter.
/// </summary>
/// <value>
/// The filter.
/// </value>
public BsonDocument Filter
{
get { return _filter; }
set { _filter = value; }
}
/// <summary>
/// Gets the name of the field.
/// </summary>
/// <value>
/// The name of the field.
/// </value>
public string FieldName
{
get { return _fieldName; }
}
/// <summary>
/// Gets or sets the maximum time the server should spend on this operation.
/// </summary>
/// <value>
/// The maximum time the server should spend on this operation.
/// </value>
public TimeSpan? MaxTime
{
get { return _maxTime; }
set { _maxTime = Ensure.IsNullOrInfiniteOrGreaterThanOrEqualToZero(value, nameof(value)); }
}
/// <summary>
/// Gets the message encoder settings.
/// </summary>
/// <value>
/// The message encoder settings.
/// </value>
public MessageEncoderSettings MessageEncoderSettings
{
get { return _messageEncoderSettings; }
}
/// <summary>
/// Gets or sets the read concern.
/// </summary>
/// <value>
/// The read concern.
/// </value>
public ReadConcern ReadConcern
{
get { return _readConcern; }
set { _readConcern = Ensure.IsNotNull(value, nameof(value)); }
}
/// <summary>
/// Gets or sets a value indicating whether to retry.
/// </summary>
/// <value>Whether to retry.</value>
public bool RetryRequested
{
get => _retryRequested;
set => _retryRequested = value;
}
/// <summary>
/// Gets the value serializer.
/// </summary>
/// <value>
/// The value serializer.
/// </value>
public IBsonSerializer<TValue> ValueSerializer
{
get { return _valueSerializer; }
}
// public methods
/// <inheritdoc/>
public IAsyncCursor<TValue> Execute(IReadBinding binding, CancellationToken cancellationToken)
{
Ensure.IsNotNull(binding, nameof(binding));
using (BeginOperation())
using (var context = RetryableReadContext.Create(binding, _retryRequested, cancellationToken))
{
var operation = CreateOperation(context);
var result = operation.Execute(context, cancellationToken);
binding.Session.SetSnapshotTimeIfNeeded(result.AtClusterTime);
return new SingleBatchAsyncCursor<TValue>(result.Values);
}
}
/// <inheritdoc/>
public async Task<IAsyncCursor<TValue>> ExecuteAsync(IReadBinding binding, CancellationToken cancellationToken)
{
Ensure.IsNotNull(binding, nameof(binding));
using (BeginOperation())
using (var context = await RetryableReadContext.CreateAsync(binding, _retryRequested, cancellationToken).ConfigureAwait(false))
{
var operation = CreateOperation(context);
var result = await operation.ExecuteAsync(context, cancellationToken).ConfigureAwait(false);
binding.Session.SetSnapshotTimeIfNeeded(result.AtClusterTime);
return new SingleBatchAsyncCursor<TValue>(result.Values);
}
}
// private methods
internal BsonDocument CreateCommand(ConnectionDescription connectionDescription, ICoreSession session)
{
var readConcern = ReadConcernHelper.GetReadConcernForCommand(session, connectionDescription, _readConcern);
return new BsonDocument
{
{ "distinct", _collectionNamespace.CollectionName },
{ "key", _fieldName },
{ "query", _filter, _filter != null },
{ "maxTimeMS", () => MaxTimeHelper.ToMaxTimeMS(_maxTime.Value), _maxTime.HasValue },
{ "collation", () => _collation.ToBsonDocument(), _collation != null },
{ "comment", _comment, _comment != null },
{ "readConcern", readConcern, readConcern != null }
};
}
private IDisposable BeginOperation() => EventContext.BeginOperation("distinct");
private ReadCommandOperation<DistinctResult> CreateOperation(RetryableReadContext context)
{
var command = CreateCommand(context.Channel.ConnectionDescription, context.Binding.Session);
var serializer = new DistinctResultDeserializer(_valueSerializer);
return new ReadCommandOperation<DistinctResult>(_collectionNamespace.DatabaseNamespace, command, serializer, _messageEncoderSettings)
{
RetryRequested = _retryRequested // might be overridden by retryable read context
};
}
private sealed class DistinctResult
{
public BsonTimestamp AtClusterTime;
public TValue[] Values;
}
private sealed class DistinctResultDeserializer : SerializerBase<DistinctResult>
{
private readonly IBsonSerializer<TValue> _valueSerializer;
public DistinctResultDeserializer(IBsonSerializer<TValue> valuesSerializer)
{
_valueSerializer = valuesSerializer;
}
public override DistinctResult Deserialize(BsonDeserializationContext context, BsonDeserializationArgs args)
{
var reader = context.Reader;
var result = new DistinctResult();
reader.ReadStartDocument();
while (reader.ReadBsonType() != 0)
{
var elementName = reader.ReadName();
switch (elementName)
{
case "atClusterTime":
result.AtClusterTime = BsonTimestampSerializer.Instance.Deserialize(context);
break;
case "values":
var arraySerializer = new ArraySerializer<TValue>(_valueSerializer);
result.Values = arraySerializer.Deserialize(context);
break;
default:
reader.SkipValue();
break;
}
}
reader.ReadEndDocument();
return result;
}
}
}
}