Jorge Canizales | e8304d5 | 2015-02-17 19:50:51 -0800 | [diff] [blame] | 1 | /* |
| 2 | * |
Jan Tattermusch | 7897ae9 | 2017-06-07 22:57:36 +0200 | [diff] [blame^] | 3 | * Copyright 2015 gRPC authors. |
Jorge Canizales | e8304d5 | 2015-02-17 19:50:51 -0800 | [diff] [blame] | 4 | * |
Jan Tattermusch | 7897ae9 | 2017-06-07 22:57:36 +0200 | [diff] [blame^] | 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 |
Jorge Canizales | e8304d5 | 2015-02-17 19:50:51 -0800 | [diff] [blame] | 8 | * |
Jan Tattermusch | 7897ae9 | 2017-06-07 22:57:36 +0200 | [diff] [blame^] | 9 | * http://www.apache.org/licenses/LICENSE-2.0 |
Jorge Canizales | e8304d5 | 2015-02-17 19:50:51 -0800 | [diff] [blame] | 10 | * |
Jan Tattermusch | 7897ae9 | 2017-06-07 22:57:36 +0200 | [diff] [blame^] | 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. |
Jorge Canizales | e8304d5 | 2015-02-17 19:50:51 -0800 | [diff] [blame] | 16 | * |
| 17 | */ |
| 18 | |
Jorge Canizales | 30697c9 | 2015-02-17 17:09:14 -0800 | [diff] [blame] | 19 | #import "GRXImmediateWriter.h" |
| 20 | |
| 21 | #import "NSEnumerator+GRXUtil.h" |
| 22 | |
| 23 | @implementation GRXImmediateWriter { |
| 24 | NSEnumerator *_enumerator; |
| 25 | NSError *_errorOrNil; |
| 26 | id<GRXWriteable> _writeable; |
| 27 | } |
| 28 | |
| 29 | @synthesize state = _state; |
| 30 | |
| 31 | - (instancetype) init { |
| 32 | return [self initWithEnumerator:nil error:nil]; // results in an empty writer. |
| 33 | } |
| 34 | |
| 35 | // Designated initializer |
| 36 | - (instancetype)initWithEnumerator:(NSEnumerator *)enumerator error:(NSError *)errorOrNil { |
| 37 | if (((self = [super init]))) { |
| 38 | _enumerator = enumerator; |
| 39 | _errorOrNil = errorOrNil; |
| 40 | _state = GRXWriterStateNotStarted; |
| 41 | } |
| 42 | return self; |
| 43 | } |
| 44 | |
| 45 | #pragma mark Convenience constructors |
| 46 | |
| 47 | + (instancetype)writerWithEnumerator:(NSEnumerator *)enumerator error:(NSError *)errorOrNil { |
| 48 | return [[self alloc] initWithEnumerator:enumerator error:errorOrNil]; |
| 49 | } |
| 50 | |
Jorge Canizales | 5604712 | 2015-07-17 12:18:08 -0700 | [diff] [blame] | 51 | + (GRXWriter *)writerWithEnumerator:(NSEnumerator *)enumerator { |
Jorge Canizales | 30697c9 | 2015-02-17 17:09:14 -0800 | [diff] [blame] | 52 | return [self writerWithEnumerator:enumerator error:nil]; |
| 53 | } |
| 54 | |
Jorge Canizales | 5604712 | 2015-07-17 12:18:08 -0700 | [diff] [blame] | 55 | + (GRXWriter *)writerWithValueSupplier:(id (^)())block { |
Jorge Canizales | 30697c9 | 2015-02-17 17:09:14 -0800 | [diff] [blame] | 56 | return [self writerWithEnumerator:[NSEnumerator grx_enumeratorWithValueSupplier:block]]; |
| 57 | } |
| 58 | |
Jorge Canizales | 5604712 | 2015-07-17 12:18:08 -0700 | [diff] [blame] | 59 | + (GRXWriter *)writerWithContainer:(id<NSFastEnumeration>)container { |
Jorge Canizales | 30697c9 | 2015-02-17 17:09:14 -0800 | [diff] [blame] | 60 | return [self writerWithEnumerator:[NSEnumerator grx_enumeratorWithContainer:container]];; |
| 61 | } |
| 62 | |
Jorge Canizales | 5604712 | 2015-07-17 12:18:08 -0700 | [diff] [blame] | 63 | + (GRXWriter *)writerWithValue:(id)value { |
Jorge Canizales | bc970ae | 2015-07-19 12:27:20 -0700 | [diff] [blame] | 64 | return [self writerWithEnumerator:[NSEnumerator grx_enumeratorWithSingleValue:value]]; |
Jorge Canizales | 30697c9 | 2015-02-17 17:09:14 -0800 | [diff] [blame] | 65 | } |
| 66 | |
Jorge Canizales | 5604712 | 2015-07-17 12:18:08 -0700 | [diff] [blame] | 67 | + (GRXWriter *)writerWithError:(NSError *)error { |
Jorge Canizales | bc970ae | 2015-07-19 12:27:20 -0700 | [diff] [blame] | 68 | return [self writerWithEnumerator:nil error:error]; |
Jorge Canizales | 30697c9 | 2015-02-17 17:09:14 -0800 | [diff] [blame] | 69 | } |
| 70 | |
Jorge Canizales | 5604712 | 2015-07-17 12:18:08 -0700 | [diff] [blame] | 71 | + (GRXWriter *)emptyWriter { |
Jorge Canizales | bc970ae | 2015-07-19 12:27:20 -0700 | [diff] [blame] | 72 | return [self writerWithEnumerator:nil error:nil]; |
Jorge Canizales | 30697c9 | 2015-02-17 17:09:14 -0800 | [diff] [blame] | 73 | } |
| 74 | |
| 75 | #pragma mark Conformance with GRXWriter |
| 76 | |
| 77 | // Most of the complexity in this implementation is the result of supporting pause and resumption of |
| 78 | // the GRXWriter. It's an important feature for instances of GRXWriter that are backed by a |
| 79 | // container (which may be huge), or by a NSEnumerator (which may even be infinite). |
| 80 | |
| 81 | - (void)writeUntilPausedOrStopped { |
| 82 | id value; |
| 83 | while (value = [_enumerator nextObject]) { |
Jorge Canizales | a90a9c3 | 2015-05-18 17:12:41 -0700 | [diff] [blame] | 84 | [_writeable writeValue:value]; |
Jorge Canizales | 30697c9 | 2015-02-17 17:09:14 -0800 | [diff] [blame] | 85 | // If the writeable has a reference to us, it might change our state to paused or finished. |
| 86 | if (_state == GRXWriterStatePaused || _state == GRXWriterStateFinished) { |
| 87 | return; |
| 88 | } |
| 89 | } |
| 90 | [self finishWithError:_errorOrNil]; |
| 91 | } |
| 92 | |
| 93 | - (void)startWithWriteable:(id<GRXWriteable>)writeable { |
| 94 | _state = GRXWriterStateStarted; |
| 95 | _writeable = writeable; |
| 96 | [self writeUntilPausedOrStopped]; |
| 97 | } |
| 98 | |
| 99 | - (void)finishWithError:(NSError *)errorOrNil { |
| 100 | _state = GRXWriterStateFinished; |
| 101 | _enumerator = nil; |
| 102 | _errorOrNil = nil; |
| 103 | id<GRXWriteable> writeable = _writeable; |
| 104 | _writeable = nil; |
Jorge Canizales | b2c300c | 2015-05-18 17:19:16 -0700 | [diff] [blame] | 105 | [writeable writesFinishedWithError:errorOrNil]; |
Jorge Canizales | 30697c9 | 2015-02-17 17:09:14 -0800 | [diff] [blame] | 106 | } |
| 107 | |
| 108 | - (void)setState:(GRXWriterState)newState { |
| 109 | // Manual transitions are only allowed from the started or paused states. |
| 110 | if (_state == GRXWriterStateNotStarted || _state == GRXWriterStateFinished) { |
| 111 | return; |
| 112 | } |
| 113 | |
| 114 | switch (newState) { |
| 115 | case GRXWriterStateFinished: |
| 116 | _state = newState; |
| 117 | _enumerator = nil; |
| 118 | _errorOrNil = nil; |
| 119 | // Per GRXWriter's contract, setting the state to Finished manually |
| 120 | // means one doesn't wish the writeable to be messaged anymore. |
| 121 | _writeable = nil; |
| 122 | return; |
| 123 | case GRXWriterStatePaused: |
| 124 | _state = newState; |
| 125 | return; |
| 126 | case GRXWriterStateStarted: |
| 127 | if (_state == GRXWriterStatePaused) { |
| 128 | _state = newState; |
| 129 | [self writeUntilPausedOrStopped]; |
| 130 | } |
| 131 | return; |
| 132 | case GRXWriterStateNotStarted: |
| 133 | return; |
| 134 | } |
| 135 | } |
| 136 | |
| 137 | @end |