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1/*
2 *
3 * Copyright 2016 gRPC authors.
4 *
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at
8 *
9 *     http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 *
17 */
18
19#import "GRXImmediateSingleWriter.h"
20
21@implementation GRXImmediateSingleWriter {
22  id _value;
23}
24
25@synthesize state = _state;
26
27- (instancetype)initWithValue:(id)value {
28  if (self = [super init]) {
29    _value = value;
30    _state = GRXWriterStateNotStarted;
31  }
32  return self;
33}
34
35+ (GRXWriter *)writerWithValue:(id)value {
36  return [[self alloc] initWithValue:value];
37}
38
39- (void)startWithWriteable:(id<GRXWriteable>)writeable {
40  id copiedValue = nil;
41  @synchronized(self) {
42    if (_state != GRXWriterStateNotStarted) {
43      return;
44    }
45    copiedValue = _value;
46    _value = nil;
47    _state = GRXWriterStateFinished;
48  }
49  [writeable writeValue:copiedValue];
50  [writeable writesFinishedWithError:nil];
51}
52
53// Overwrite the setter to disallow manual state transition. The getter
54// of _state is synthesized.
55- (void)setState:(GRXWriterState)newState {
56  // Manual state transition is not allowed
57  return;
58}
59
60// Overrides [requestWriter(Transformations):map:] for Protocol Buffers
61// encoding.
62// We need the return value of this map to be a GRXImmediateSingleWriter but
63// the original \a map function returns a new Writer of another type. So we
64// need to override this function here.
65- (GRXWriter *)map:(id (^)(id))map {
66  @synchronized(self) {
67    // Since _value is available when creating the object, we can simply
68    // apply the map and store the output.
69    _value = map(_value);
70  }
71  return self;
72}
73
74@end
75