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Merge pull request grpc#1647 from jcanizales/buffered-pipe-and-ping-p…
…ong-test Adds GRXBufferedPipe and the PingPong interop test using it
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| /* | ||
| * | ||
| * Copyright 2015, Google Inc. | ||
| * All rights reserved. | ||
| * | ||
| * Redistribution and use in source and binary forms, with or without | ||
| * modification, are permitted provided that the following conditions are | ||
| * met: | ||
| * | ||
| * * Redistributions of source code must retain the above copyright | ||
| * notice, this list of conditions and the following disclaimer. | ||
| * * Redistributions in binary form must reproduce the above | ||
| * copyright notice, this list of conditions and the following disclaimer | ||
| * in the documentation and/or other materials provided with the | ||
| * distribution. | ||
| * * Neither the name of Google Inc. nor the names of its | ||
| * contributors may be used to endorse or promote products derived from | ||
| * this software without specific prior written permission. | ||
| * | ||
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | ||
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | ||
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR | ||
| * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT | ||
| * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, | ||
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT | ||
| * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | ||
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | ||
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | ||
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE | ||
| * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | ||
| * | ||
| */ | ||
|
|
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| #import <Foundation/Foundation.h> | ||
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| #import "GRXWriteable.h" | ||
| #import "GRXWriter.h" | ||
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| // A buffered pipe is a Writeable that also acts as a Writer (to whichever other writeable is passed | ||
| // to -startWithWriteable:). | ||
| // Once it is started, whatever values are written into it (via -didReceiveValue:) will be | ||
| // propagated immediately, unless flow control prevents it. | ||
| // If it is throttled and keeps receiving values, as well as if it receives values before being | ||
| // started, it will buffer them and propagate them in order as soon as its state becomes | ||
| // GRXWriterStateStarted. | ||
| // If it receives an error (via -didFinishWithError:), it will drop any buffered values and | ||
| // propagate the error immediately. | ||
| // | ||
| // Beware that a pipe of this type can't prevent receiving more values when it is paused (for | ||
| // example if used to write data to a congested network connection). Because in such situations the | ||
| // pipe will keep buffering all data written to it, your application could run out of memory and | ||
| // crash. If you want to react to flow control signals to prevent that, instead of using this class | ||
| // you can implement an object that conforms to GRXWriter. | ||
| @interface GRXBufferedPipe : NSObject<GRXWriteable, GRXWriter> | ||
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| // Convenience constructor. | ||
| + (instancetype)pipe; | ||
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| @end |
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| Original file line number | Diff line number | Diff line change |
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| @@ -0,0 +1,146 @@ | ||
| /* | ||
| * | ||
| * Copyright 2015, Google Inc. | ||
| * All rights reserved. | ||
| * | ||
| * Redistribution and use in source and binary forms, with or without | ||
| * modification, are permitted provided that the following conditions are | ||
| * met: | ||
| * | ||
| * * Redistributions of source code must retain the above copyright | ||
| * notice, this list of conditions and the following disclaimer. | ||
| * * Redistributions in binary form must reproduce the above | ||
| * copyright notice, this list of conditions and the following disclaimer | ||
| * in the documentation and/or other materials provided with the | ||
| * distribution. | ||
| * * Neither the name of Google Inc. nor the names of its | ||
| * contributors may be used to endorse or promote products derived from | ||
| * this software without specific prior written permission. | ||
| * | ||
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | ||
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | ||
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR | ||
| * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT | ||
| * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, | ||
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT | ||
| * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | ||
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | ||
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | ||
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE | ||
| * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | ||
| * | ||
| */ | ||
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| #import "GRXBufferedPipe.h" | ||
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| @implementation GRXBufferedPipe { | ||
| id<GRXWriteable> _writeable; | ||
| NSMutableArray *_queue; | ||
| BOOL _inputIsFinished; | ||
| NSError *_errorOrNil; | ||
| } | ||
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| @synthesize state = _state; | ||
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| + (instancetype)pipe { | ||
| return [[self alloc] init]; | ||
| } | ||
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| - (instancetype)init { | ||
| if (self = [super init]) { | ||
| _queue = [NSMutableArray array]; | ||
| _state = GRXWriterStateNotStarted; | ||
| } | ||
| return self; | ||
| } | ||
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| - (id)popValue { | ||
| id value = _queue[0]; | ||
| [_queue removeObjectAtIndex:0]; | ||
| return value; | ||
| } | ||
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| - (void)writeBufferUntilPausedOrStopped { | ||
| while (_state == GRXWriterStateStarted && _queue.count > 0) { | ||
| [_writeable didReceiveValue:[self popValue]]; | ||
| } | ||
| if (_inputIsFinished && _queue.count == 0) { | ||
| // Our writer finished normally while we were paused or not-started-yet. | ||
| [self finishWithError:_errorOrNil]; | ||
| } | ||
| } | ||
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| #pragma mark GRXWriteable implementation | ||
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| // Returns whether events can be simply propagated to the other end of the pipe. | ||
| - (BOOL)shouldFastForward { | ||
| return _state == GRXWriterStateStarted && _queue.count == 0; | ||
| } | ||
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| - (void)didReceiveValue:(id)value { | ||
| if (self.shouldFastForward) { | ||
| // Skip the queue. | ||
| [_writeable didReceiveValue:value]; | ||
| } else { | ||
| // Even if we're paused and with enqueued values, we can't excert back-pressure to our writer. | ||
| // So just buffer the new value. | ||
| // We need a copy, so that it doesn't mutate before it's written at the other end of the pipe. | ||
| if ([value respondsToSelector:@selector(copy)]) { | ||
| value = [value copy]; | ||
| } | ||
| [_queue addObject:value]; | ||
| } | ||
| } | ||
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| - (void)didFinishWithError:(NSError *)errorOrNil { | ||
| _inputIsFinished = YES; | ||
| _errorOrNil = errorOrNil; | ||
| if (errorOrNil || self.shouldFastForward) { | ||
| // No need to write pending values. | ||
| [self finishWithError:_errorOrNil]; | ||
| } | ||
| } | ||
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| #pragma mark GRXWriter implementation | ||
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| - (void)setState:(GRXWriterState)newState { | ||
| // Manual transitions are only allowed from the started or paused states. | ||
| if (_state == GRXWriterStateNotStarted || _state == GRXWriterStateFinished) { | ||
| return; | ||
| } | ||
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| switch (newState) { | ||
| case GRXWriterStateFinished: | ||
| _state = newState; | ||
| _queue = nil; | ||
| // Per GRXWriter's contract, setting the state to Finished manually means one doesn't wish the | ||
| // writeable to be messaged anymore. | ||
| _writeable = nil; | ||
| return; | ||
| case GRXWriterStatePaused: | ||
| _state = newState; | ||
| return; | ||
| case GRXWriterStateStarted: | ||
| if (_state == GRXWriterStatePaused) { | ||
| _state = newState; | ||
| [self writeBufferUntilPausedOrStopped]; | ||
| } | ||
| return; | ||
| case GRXWriterStateNotStarted: | ||
| return; | ||
| } | ||
| } | ||
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| - (void)startWithWriteable:(id<GRXWriteable>)writeable { | ||
| _state = GRXWriterStateStarted; | ||
| _writeable = writeable; | ||
| [self writeBufferUntilPausedOrStopped]; | ||
| } | ||
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| - (void)finishWithError:(NSError *)errorOrNil { | ||
| id<GRXWriteable> writeable = _writeable; | ||
| self.state = GRXWriterStateFinished; | ||
| [writeable didFinishWithError:errorOrNil]; | ||
| } | ||
|
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| @end |
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