Server/EchoConnection.m
/* |
File: EchoConnection.m |
Contains: Manages a single echo connection. |
Copyright: Copyright (c) 2012 Apple Inc. All Rights Reserved. |
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*/ |
#import "EchoConnection.h" |
NSString * EchoConnectionDidCloseNotification = @"EchoConnectionDidCloseNotification"; |
@interface EchoConnection () <NSStreamDelegate> |
@end |
@implementation EchoConnection |
@synthesize inputStream = _inputStream; |
@synthesize outputStream = _outputStream; |
- (id)initWithInputStream:(NSInputStream *)inputStream outputStream:(NSOutputStream *)outputStream |
{ |
self = [super init]; |
if (self != nil) { |
self->_inputStream = inputStream; |
self->_outputStream = outputStream; |
} |
return self; |
} |
- (BOOL)open { |
[self.inputStream setDelegate:self]; |
[self.outputStream setDelegate:self]; |
[self.inputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode]; |
[self.outputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode]; |
[self.inputStream open]; |
[self.outputStream open]; |
return YES; |
} |
- (void)close { |
[self.inputStream setDelegate:nil]; |
[self.outputStream setDelegate:nil]; |
[self.inputStream close]; |
[self.outputStream close]; |
[self.inputStream removeFromRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode]; |
[self.outputStream removeFromRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode]; |
[(NSNotificationCenter *)[NSNotificationCenter defaultCenter] postNotificationName:EchoConnectionDidCloseNotification object:self]; |
} |
- (void)stream:(NSStream *)aStream handleEvent:(NSStreamEvent)streamEvent { |
assert(aStream == self.inputStream || aStream == self.outputStream); |
#pragma unused(aStream) |
switch(streamEvent) { |
case NSStreamEventHasBytesAvailable: { |
uint8_t buffer[2048]; |
NSInteger actuallyRead = [self.inputStream read:(uint8_t *)buffer maxLength:sizeof(buffer)]; |
if (actuallyRead > 0) { |
NSInteger actuallyWritten = [self.outputStream write:buffer maxLength:(NSUInteger)actuallyRead]; |
if (actuallyWritten != actuallyRead) { |
// -write:maxLength: may return -1 to indicate an error or a non-negative |
// value less than maxLength to indicate a 'short write'. In the case of an |
// error we just shut down the connection. The short write case is more |
// interesting. A short write means that the client has sent us data to echo but |
// isn't reading the data that we send back to it, thus causing its socket receive |
// buffer to fill up, thus causing our socket send buffer to fill up. Again, our |
// response to this situation is that we simply drop the connection. |
[self close]; |
} else { |
NSLog(@"Echoed %zd bytes.", (ssize_t) actuallyWritten); |
} |
} else { |
// A non-positive value from -read:maxLength: indicates either end of file (0) or |
// an error (-1). In either case we just wait for the corresponding stream event |
// to come through. |
} |
} break; |
case NSStreamEventEndEncountered: |
case NSStreamEventErrorOccurred: { |
[self close]; |
} break; |
case NSStreamEventHasSpaceAvailable: |
case NSStreamEventOpenCompleted: |
default: { |
// do nothing |
} break; |
} |
} |
@end |
Copyright © 2012 Apple Inc. All Rights Reserved. Terms of Use | Privacy Policy | Updated: 2012-08-17