Retired Document
Important: This sample code may not represent best practices for current development. The project may use deprecated symbols and illustrate technologies and techniques that are no longer recommended.
Relevant replacement documents include:
PublicUtility/CAGuard.cpp
/* |
File: CAGuard.cpp |
Abstract: CAGuard.h |
Version: 1.1 |
Disclaimer: IMPORTANT: This Apple software is supplied to you by Apple |
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Neither the name, trademarks, service marks or logos of Apple Inc. may |
be used to endorse or promote products derived from the Apple Software |
without specific prior written permission from Apple. Except as |
expressly stated in this notice, no other rights or licenses, express or |
implied, are granted by Apple herein, including but not limited to any |
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The Apple Software is provided by Apple on an "AS IS" basis. APPLE |
MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION |
THE IMPLIED WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS |
FOR A PARTICULAR PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND |
OPERATION ALONE OR IN COMBINATION WITH YOUR PRODUCTS. |
IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL |
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Copyright (C) 2012 Apple Inc. All Rights Reserved. |
*/ |
//================================================================================================== |
// Includes |
//================================================================================================== |
// Self Include |
#include "CAGuard.h" |
#if TARGET_OS_MAC |
#include <errno.h> |
#endif |
// PublicUtility Inludes |
#include "CADebugMacros.h" |
#include "CAException.h" |
#include "CAHostTimeBase.h" |
//================================================================================================== |
// Logging |
//================================================================================================== |
#if CoreAudio_Debug |
// #define Log_Ownership 1 |
// #define Log_WaitOwnership 1 |
// #define Log_TimedWaits 1 |
// #define Log_Latency 1 |
// #define Log_Errors 1 |
#endif |
//#warning Need a try-based Locker too |
//================================================================================================== |
// CAGuard |
//================================================================================================== |
CAGuard::CAGuard(const char* inName) |
: |
CAMutex(inName) |
#if Log_Average_Latency |
,mAverageLatencyAccumulator(0.0), |
mAverageLatencyCount(0) |
#endif |
{ |
#if TARGET_OS_MAC |
OSStatus theError = pthread_cond_init(&mCondVar, NULL); |
ThrowIf(theError != 0, CAException(theError), "CAGuard::CAGuard: Could not init the cond var"); |
#elif TARGET_OS_WIN32 |
mEvent = CreateEvent(NULL, true, false, NULL); |
ThrowIfNULL(mEvent, CAException(GetLastError()), "CAGuard::CAGuard: Could not create the event"); |
#endif |
} |
CAGuard::~CAGuard() |
{ |
#if TARGET_OS_MAC |
pthread_cond_destroy(&mCondVar); |
#elif TARGET_OS_WIN32 |
if(mEvent != NULL) |
{ |
CloseHandle(mEvent); |
} |
#endif |
} |
void CAGuard::Wait() |
{ |
#if TARGET_OS_MAC |
ThrowIf(!pthread_equal(pthread_self(), mOwner), CAException(1), "CAGuard::Wait: A thread has to have locked a guard before it can wait"); |
mOwner = 0; |
#if Log_WaitOwnership |
DebugPrintfRtn(DebugPrintfFileComma "%p %.4f: CAGuard::Wait: thread %p is waiting on %s, owner: %p\n", pthread_self(), ((Float64)(CAHostTimeBase::GetCurrentTimeInNanos()) / 1000000.0), pthread_self(), mName, mOwner); |
#endif |
OSStatus theError = pthread_cond_wait(&mCondVar, &mMutex); |
ThrowIf(theError != 0, CAException(theError), "CAGuard::Wait: Could not wait for a signal"); |
mOwner = pthread_self(); |
#if Log_WaitOwnership |
DebugPrintfRtn(DebugPrintfFileComma "%p %.4f: CAGuard::Wait: thread %p waited on %s, owner: %p\n", pthread_self(), ((Float64)(CAHostTimeBase::GetCurrentTimeInNanos()) / 1000000.0), pthread_self(), mName, mOwner); |
#endif |
#elif TARGET_OS_WIN32 |
ThrowIf(GetCurrentThreadId() != mOwner, CAException(1), "CAGuard::Wait: A thread has to have locked a guard before it can wait"); |
mOwner = 0; |
#if Log_WaitOwnership |
DebugPrintfRtn(DebugPrintfFileComma "%lu %.4f: CAGuard::Wait: thread %lu is waiting on %s, owner: %lu\n", GetCurrentThreadId(), ((Float64)(CAHostTimeBase::GetCurrentTimeInNanos()) / 1000000.0), GetCurrentThreadId(), mName, mOwner); |
#endif |
ReleaseMutex(mMutex); |
HANDLE theHandles[] = { mMutex, mEvent }; |
OSStatus theError = WaitForMultipleObjects(2, theHandles, true, INFINITE); |
ThrowIfError(theError, CAException(GetLastError()), "CAGuard::Wait: Could not wait for the signal"); |
mOwner = GetCurrentThreadId(); |
ResetEvent(mEvent); |
#if Log_WaitOwnership |
DebugPrintfRtn(DebugPrintfFileComma "%lu %.4f: CAGuard::Wait: thread %lu waited on %s, owner: %lu\n", GetCurrentThreadId(), ((Float64)(CAHostTimeBase::GetCurrentTimeInNanos()) / 1000000.0), GetCurrentThreadId(), mName, mOwner); |
#endif |
#endif |
} |
bool CAGuard::WaitFor(UInt64 inNanos) |
{ |
bool theAnswer = false; |
#if TARGET_OS_MAC |
ThrowIf(!pthread_equal(pthread_self(), mOwner), CAException(1), "CAGuard::WaitFor: A thread has to have locked a guard be for it can wait"); |
#if Log_TimedWaits |
DebugMessageN1("CAGuard::WaitFor: waiting %.0f", (Float64)inNanos); |
#endif |
struct timespec theTimeSpec; |
static const UInt64 kNanosPerSecond = 1000000000ULL; |
if(inNanos >= kNanosPerSecond) |
{ |
theTimeSpec.tv_sec = static_cast<UInt32>(inNanos / kNanosPerSecond); |
theTimeSpec.tv_nsec = static_cast<UInt32>(inNanos % kNanosPerSecond); |
} |
else |
{ |
theTimeSpec.tv_sec = 0; |
theTimeSpec.tv_nsec = static_cast<UInt32>(inNanos); |
} |
#if Log_TimedWaits || Log_Latency || Log_Average_Latency |
UInt64 theStartNanos = CAHostTimeBase::GetCurrentTimeInNanos(); |
#endif |
mOwner = 0; |
#if Log_WaitOwnership |
DebugPrintfRtn(DebugPrintfFileComma "%p %.4f: CAGuard::WaitFor: thread %p is waiting on %s, owner: %p\n", pthread_self(), ((Float64)(CAHostTimeBase::GetCurrentTimeInNanos()) / 1000000.0), pthread_self(), mName, mOwner); |
#endif |
OSStatus theError = pthread_cond_timedwait_relative_np(&mCondVar, &mMutex, &theTimeSpec); |
ThrowIf((theError != 0) && (theError != ETIMEDOUT), CAException(theError), "CAGuard::WaitFor: Wait got an error"); |
mOwner = pthread_self(); |
#if Log_TimedWaits || Log_Latency || Log_Average_Latency |
UInt64 theEndNanos = CAHostTimeBase::GetCurrentTimeInNanos(); |
#endif |
#if Log_TimedWaits |
DebugMessageN1("CAGuard::WaitFor: waited %.0f", (Float64)(theEndNanos - theStartNanos)); |
#endif |
#if Log_Latency |
DebugMessageN1("CAGuard::WaitFor: latency %.0f", (Float64)((theEndNanos - theStartNanos) - inNanos)); |
#endif |
#if Log_Average_Latency |
++mAverageLatencyCount; |
mAverageLatencyAccumulator += (theEndNanos - theStartNanos) - inNanos; |
if(mAverageLatencyCount >= 50) |
{ |
DebugMessageN2("CAGuard::WaitFor: average latency %.3f ns over %ld waits", mAverageLatencyAccumulator / mAverageLatencyCount, mAverageLatencyCount); |
mAverageLatencyCount = 0; |
mAverageLatencyAccumulator = 0.0; |
} |
#endif |
#if Log_WaitOwnership |
DebugPrintfRtn(DebugPrintfFileComma "%p %.4f: CAGuard::WaitFor: thread %p waited on %s, owner: %p\n", pthread_self(), ((Float64)(CAHostTimeBase::GetCurrentTimeInNanos()) / 1000000.0), pthread_self(), mName, mOwner); |
#endif |
theAnswer = theError == ETIMEDOUT; |
#elif TARGET_OS_WIN32 |
ThrowIf(GetCurrentThreadId() != mOwner, CAException(1), "CAGuard::WaitFor: A thread has to have locked a guard be for it can wait"); |
#if Log_TimedWaits |
DebugMessageN1("CAGuard::WaitFor: waiting %.0f", (Float64)inNanos); |
#endif |
// the time out is specified in milliseconds(!) |
UInt32 theWaitTime = static_cast<UInt32>(inNanos / 1000000ULL); |
#if Log_TimedWaits || Log_Latency || Log_Average_Latency |
UInt64 theStartNanos = CAHostTimeBase::GetCurrentTimeInNanos(); |
#endif |
mOwner = 0; |
#if Log_WaitOwnership |
DebugPrintfRtn(DebugPrintfFileComma "%lu %.4f: CAGuard::WaitFor: thread %lu is waiting on %s, owner: %lu\n", GetCurrentThreadId(), ((Float64)(CAHostTimeBase::GetCurrentTimeInNanos()) / 1000000.0), GetCurrentThreadId(), mName, mOwner); |
#endif |
ReleaseMutex(mMutex); |
HANDLE theHandles[] = { mMutex, mEvent }; |
OSStatus theError = WaitForMultipleObjects(2, theHandles, true, theWaitTime); |
ThrowIf((theError != WAIT_OBJECT_0) && (theError != WAIT_TIMEOUT), CAException(GetLastError()), "CAGuard::WaitFor: Wait got an error"); |
mOwner = GetCurrentThreadId(); |
ResetEvent(mEvent); |
#if Log_TimedWaits || Log_Latency || Log_Average_Latency |
UInt64 theEndNanos = CAHostTimeBase::GetCurrentTimeInNanos(); |
#endif |
#if Log_TimedWaits |
DebugMessageN1("CAGuard::WaitFor: waited %.0f", (Float64)(theEndNanos - theStartNanos)); |
#endif |
#if Log_Latency |
DebugMessageN1("CAGuard::WaitFor: latency %.0f", (Float64)((theEndNanos - theStartNanos) - inNanos)); |
#endif |
#if Log_Average_Latency |
++mAverageLatencyCount; |
mAverageLatencyAccumulator += (theEndNanos - theStartNanos) - inNanos; |
if(mAverageLatencyCount >= 50) |
{ |
DebugMessageN2("CAGuard::WaitFor: average latency %.3f ns over %ld waits", mAverageLatencyAccumulator / mAverageLatencyCount, mAverageLatencyCount); |
mAverageLatencyCount = 0; |
mAverageLatencyAccumulator = 0.0; |
} |
#endif |
#if Log_WaitOwnership |
DebugPrintfRtn(DebugPrintfFileComma "%lu %.4f: CAGuard::WaitFor: thread %lu waited on %s, owner: %lu\n", GetCurrentThreadId(), ((Float64)(CAHostTimeBase::GetCurrentTimeInNanos()) / 1000000.0), GetCurrentThreadId(), mName, mOwner); |
#endif |
theAnswer = theError == WAIT_TIMEOUT; |
#endif |
return theAnswer; |
} |
bool CAGuard::WaitUntil(UInt64 inNanos) |
{ |
bool theAnswer = false; |
UInt64 theCurrentNanos = CAHostTimeBase::GetCurrentTimeInNanos(); |
#if Log_TimedWaits |
DebugMessageN2("CAGuard::WaitUntil: now: %.0f, requested: %.0f", (double)theCurrentNanos, (double)inNanos); |
#endif |
if(inNanos > theCurrentNanos) |
{ |
#if Log_Errors |
if((inNanos - theCurrentNanos) > 1000000000ULL) |
{ |
DebugMessage("CAGuard::WaitUntil: about to wait for more than a second"); |
} |
#endif |
theAnswer = WaitFor(inNanos - theCurrentNanos); |
} |
else |
{ |
#if Log_Errors |
DebugMessageN2("CAGuard::WaitUntil: Time has expired before waiting, now: %.0f, requested: %.0f", (double)theCurrentNanos, (double)inNanos); |
#endif |
theAnswer = true; |
} |
return theAnswer; |
} |
void CAGuard::Notify() |
{ |
#if TARGET_OS_MAC |
#if Log_WaitOwnership |
DebugPrintfRtn(DebugPrintfFileComma "%p %.4f: CAGuard::Notify: thread %p is notifying %s, owner: %p\n", pthread_self(), ((Float64)(CAHostTimeBase::GetCurrentTimeInNanos()) / 1000000.0), pthread_self(), mName, mOwner); |
#endif |
OSStatus theError = pthread_cond_signal(&mCondVar); |
ThrowIf(theError != 0, CAException(theError), "CAGuard::Notify: failed"); |
#elif TARGET_OS_WIN32 |
#if Log_WaitOwnership |
DebugPrintfRtn(DebugPrintfFileComma "%lu %.4f: CAGuard::Notify: thread %lu is notifying %s, owner: %lu\n", GetCurrentThreadId(), ((Float64)(CAHostTimeBase::GetCurrentTimeInNanos()) / 1000000.0), GetCurrentThreadId(), mName, mOwner); |
#endif |
SetEvent(mEvent); |
#endif |
} |
void CAGuard::NotifyAll() |
{ |
#if TARGET_OS_MAC |
#if Log_WaitOwnership |
DebugPrintfRtn(DebugPrintfFileComma "%p %.4f: CAGuard::NotifyAll: thread %p is notifying %s, owner: %p\n", pthread_self(), ((Float64)(CAHostTimeBase::GetCurrentTimeInNanos()) / 1000000.0), pthread_self(), mName, mOwner); |
#endif |
OSStatus theError = pthread_cond_broadcast(&mCondVar); |
ThrowIf(theError != 0, CAException(theError), "CAGuard::NotifyAll: failed"); |
#elif TARGET_OS_WIN32 |
#if Log_WaitOwnership |
DebugPrintfRtn(DebugPrintfFileComma "%lu %.4f: CAGuard::NotifyAll: thread %lu is notifying %s, owner: %lu\n", GetCurrentThreadId(), ((Float64)(CAHostTimeBase::GetCurrentTimeInNanos()) / 1000000.0), GetCurrentThreadId(), mName, mOwner); |
#endif |
SetEvent(mEvent); |
#endif |
} |
Copyright © 2012 Apple Inc. All Rights Reserved. Terms of Use | Privacy Policy | Updated: 2012-10-16