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PKTaskQueue.cpp
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PKTaskQueue.cpp
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/*
* PKTaskQueue.cpp
* PlayerKit
*
* Created by James MacWhinnie on 3/19/10.
* Copyright 2010 Roundabout Software. All rights reserved.
*
*/
#include "PKTaskQueue.h"
#include "CAPThread.h"
#include <dlfcn.h>
//We load the objc_[un]registerThreadWithCollector functions at runtime
//so we don't have to link the objc runtime in PlayerKit.
typedef void(*ObjCGarbageCollectorProc)();
static ObjCGarbageCollectorProc objc_registerThreadWithCollector = (ObjCGarbageCollectorProc)dlsym(RTLD_DEFAULT, "objc_registerThreadWithCollector");
static ObjCGarbageCollectorProc objc_unregisterThreadWithCollector = (ObjCGarbageCollectorProc)dlsym(RTLD_DEFAULT, "objc_unregisterThreadWithCollector");
#pragma mark PKTaskQueue
static void TaskBlockForwarder(void *userInfo)
{
PKTaskQueue::TaskBlock block = (PKTaskQueue::TaskBlock)userInfo;
block();
Block_release(block);
}
#pragma mark -
#pragma mark Constructor/Destructor
PKTaskQueue::PKTaskQueue(const char *name) :
RBLockableObject("PKTaskQueue"),
mName(strdup(name)),
mQueueTasks(),
mIsCancelled(false),
mSleepSemaphore("PKTaskQueue::mSleepSemaphore"),
mProcessingThread(NULL)
{
}
PKTaskQueue::~PKTaskQueue()
{
free((void *)(mName));
mName = NULL;
}
#pragma mark -
#pragma mark Describing PKTaskQueue
CFStringRef PKTaskQueue::CopyDescription()
{
return CFStringCreateWithFormat(kCFAllocatorDefault, NULL, CFSTR("<%s:%p %s>"), mClassName, this, mName);
}
#pragma mark -
#pragma mark Processing Thread
void PKTaskQueue::StartProcessingThread()
{
Acquisitor lock(this);
mIsCancelled = false;
if(!mProcessingThread)
{
mProcessingThread = new CAPThread(CAPThread::ThreadRoutine(&ProcessingThreadCallback), //in threadRoutine
this, //in threadRoutineUserInfo
CAPThread::kMaxThreadPriority, //in priority
true, //in isPriorityFixed?
true); //in shouldAutoDelete?
mProcessingThread->Start();
}
}
void PKTaskQueue::StopProcessingThread()
{
mIsCancelled = true;
mSleepSemaphore.SignalIf(^(int value) { return value > 1; });
}
#pragma mark -
void *PKTaskQueue::ProcessingThreadCallback(PKTaskQueue *self)
{
if(objc_registerThreadWithCollector) objc_registerThreadWithCollector();
self->Retain();
pthread_setname_np(self->mName);
while (!self->mIsCancelled)
{
while (self->mQueueTasks.size() > 0)
{
QueuedTask *topTask = NULL;
{
Acquisitor lock(self);
topTask = self->mQueueTasks.front();
self->mQueueTasks.pop();
}
try
{
(*topTask)();
}
catch (...)
{
std::cerr << "An unexpected exception was raised in the PKTaskQueue named " << self->mName << std::endl;
}
topTask->Release();
}
try
{
self->mSleepSemaphore.Wait();
}
catch (RBException e)
{
std::cerr << "mSleepSemaphore.Wait failed with error code " << e.GetCode() << ". Aborting." << std::endl;
}
}
self->mProcessingThread = NULL;
self->Release();
if(objc_unregisterThreadWithCollector) objc_unregisterThreadWithCollector();
return NULL;
}
#pragma mark -
#pragma mark Queuing Tasks
void PKTaskQueue::Async(TaskProc proc, void *userInfo)
{
RBParameterAssert(proc);
Acquisitor lock(this);
//Start the processing thread if it hasn't been already
if(!mProcessingThread)
this->StartProcessingThread();
QueuedTask *task = new QueuedTask(proc, userInfo, true);
mQueueTasks.push(task);
mSleepSemaphore.SignalIf(^(int value) { return value > 0; });
}
void PKTaskQueue::Async(TaskBlock block)
{
RBParameterAssert(block);
this->Async(&TaskBlockForwarder, Block_copy(block));
}
#pragma mark -
void PKTaskQueue::Sync(TaskProc proc, void *userInfo)
{
RBParameterAssert(proc);
Acquisitor lock(this);
//Start the processing thread if it hasn't been already
if(!mProcessingThread)
this->StartProcessingThread();
QueuedTask *task = new QueuedTask(proc, userInfo, true);
//We retain the task so it can't be destroyed out from underneath us if it's processed and released
task->Retain();
mQueueTasks.push(task);
try
{
mSleepSemaphore.SignalIf(^(int value) { return value > 0; });
//We relinquish `lock` before waiting for a signal so we don't cause a deadlock
lock.Relinquish();
task->WaitForApplication();
}
catch (...)
{
//Balance the above retain
task->Release();
throw;
}
//Balance the above retain
task->Release();
}
void PKTaskQueue::Sync(TaskBlock block)
{
RBParameterAssert(block);
this->Sync(&TaskBlockForwarder, Block_copy(block));
}