1  /*
  2   * Copyright (c) 2014 Apple Inc. All Rights Reserved.
  3   * 
  4   * @APPLE_LICENSE_HEADER_START@
  5   * 
  6   * This file contains Original Code and/or Modifications of Original Code
  7   * as defined in and that are subject to the Apple Public Source License
  8   * Version 2.0 (the 'License'). You may not use this file except in
  9   * compliance with the License. Please obtain a copy of the License at
 10   * http://www.opensource.apple.com/apsl/ and read it before using this
 11   * file.
 12   * 
 13   * The Original Code and all software distributed under the License are
 14   * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 15   * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 16   * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 17   * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 18   * Please see the License for the specific language governing rights and
 19   * limitations under the License.
 20   * 
 21   * @APPLE_LICENSE_HEADER_END@
 22   */
 23  
 24  //
 25  // dispatch - libdispatch wrapper
 26  //
 27  #include "dispatch.h"
 28  #include <security_utilities/errors.h>
 29  
 30  namespace Security {
 31  namespace Dispatch {
 32  
 33  ExceptionAwareEnqueuing::ExceptionAwareEnqueuing()
 34  : mExceptionPending(false)
 35  { }
 36  
 37  void ExceptionAwareEnqueuing::enqueueWithDispatcher(void (^dispatcher)(dispatch_block_t), dispatch_block_t block)
 38  {
 39  	if (mExceptionPending)
 40  		return;
 41  
 42  	dispatcher(^{
 43  		if (mExceptionPending)
 44  			return;
 45  		try {
 46  			block();
 47  		} catch (...) {
 48  			StLock<Mutex> _(mLock);
 49  			mExceptionPending = true;
 50  			mException = std::current_exception();
 51  		}
 52  	});
 53  }
 54  
 55  void ExceptionAwareEnqueuing::throwPendingException()
 56  {
 57  	if (mExceptionPending) {
 58  		mExceptionPending = false;
 59  		std::rethrow_exception(mException);
 60  	}
 61  }
 62  
 63  
 64  
 65  Queue::Queue(const char *label, bool concurrent, dispatch_qos_class_t qos_class)
 66  {
 67  	dispatch_queue_attr_t attr = concurrent ? DISPATCH_QUEUE_CONCURRENT : DISPATCH_QUEUE_SERIAL;
 68  	attr = dispatch_queue_attr_make_with_qos_class(attr, qos_class, 0);
 69  	mQueue = dispatch_queue_create(label, attr);
 70  }
 71  
 72  Queue::~Queue()
 73  {
 74  	dispatch_barrier_sync(mQueue, ^{});
 75  	dispatch_release(mQueue);
 76  }
 77  
 78  void Queue::enqueue(dispatch_block_t block)
 79  {
 80  	enqueuing.enqueueWithDispatcher(^(dispatch_block_t block){ dispatch_async(mQueue, block); }, block);
 81  }
 82  
 83  void Queue::wait()
 84  {
 85  	dispatch_barrier_sync(mQueue, ^{});
 86  	enqueuing.throwPendingException();
 87  }
 88  
 89  
 90  
 91  Group::Group()
 92  {
 93  	mGroup = dispatch_group_create();
 94  }
 95  
 96  Group::~Group()
 97  {
 98  	dispatch_group_wait(mGroup, DISPATCH_TIME_FOREVER);
 99  	dispatch_release(mGroup);
100  }
101  
102  void Group::enqueue(dispatch_queue_t queue, dispatch_block_t block)
103  {
104  	enqueuing.enqueueWithDispatcher(^(dispatch_block_t block){ dispatch_group_async(mGroup, queue, block); }, block);
105  }
106  
107  void Group::wait()
108  {
109  	dispatch_group_wait(mGroup, DISPATCH_TIME_FOREVER);
110  	enqueuing.throwPendingException();
111  }
112  
113  
114  
115  Semaphore::Semaphore(long count) {
116  	mSemaphore = dispatch_semaphore_create(count);
117  }
118  
119  Semaphore::Semaphore(Semaphore& semaphore)
120  : mSemaphore(semaphore.mSemaphore)
121  {
122  	dispatch_retain(mSemaphore);
123  }
124  
125  Semaphore::~Semaphore() {
126  	dispatch_release(mSemaphore);
127  }
128  
129  bool Semaphore::signal() {
130  	return dispatch_semaphore_signal(mSemaphore) == 0;
131  }
132  
133  bool Semaphore::wait(dispatch_time_t timeout) {
134  	return dispatch_semaphore_wait(mSemaphore, timeout) == 0;
135  }
136  
137  
138  // Transfer ownership of held resource.
139  SemaphoreWait::SemaphoreWait(SemaphoreWait &originalWait)
140  : mSemaphore(originalWait.mSemaphore), mAcquired(originalWait.mAcquired)
141  {
142  	originalWait.mAcquired = false;
143  }
144  
145  SemaphoreWait::SemaphoreWait(Semaphore &semaphore, dispatch_time_t timeout)
146  : mSemaphore(semaphore)
147  {
148  	mAcquired = mSemaphore.wait(timeout);
149  }
150  
151  SemaphoreWait::~SemaphoreWait()
152  {
153  	if (mAcquired)
154  		mSemaphore.signal();
155  }
156  
157  
158  } // end namespace Dispatch
159  } // end namespace Security