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/*
* Copyright (c) 2005, Eric Crahen
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is furnished
* to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
*/
#include "ThreadOps.h"
#include "zthread/Runnable.h"
#include <process.h>
namespace ZThread {
const ThreadOps ThreadOps::INVALID(0);
/**
* Detect OS at runtime and attempt to locate the SwitchToThread
* function, which will assist in making the spin lock implementation
* which use ThreadOps::yield() a bit fairer.
*/
class YieldOps {
typedef BOOL (*Yield)(void);
Yield _fnYield;
public:
YieldOps() : _fnYield(NULL) {
OSVERSIONINFO v;
v.dwOSVersionInfoSize = sizeof(OSVERSIONINFO);
if(::GetVersionEx(&v) && (v.dwPlatformId == VER_PLATFORM_WIN32_NT)) {
// Uses GetModuleHandle() so the reference count on the dll is
// not affected. There is a warning about race conditions involving
// this function being called as FreeLibrary() completes; however
// nearly all win32 applications load this particular and will keep it
// in memory until the process exits.
HINSTANCE hInst = ::GetModuleHandle("Kernel32.dll");
if(hInst != NULL)
_fnYield = (Yield)::GetProcAddress(hInst, "SwitchToThread");
// REMIND: possibly need to use _T() macro for these strings
}
}
bool operator()() {
// Attempt to yield using the best function available
if(!_fnYield || !_fnYield())
::Sleep(0);
return true;
}
};
bool ThreadOps::join(ThreadOps* ops) {
assert(ops);
assert(ops->_tid != 0);
assert(ops->_hThread != NULL);
if(::WaitForSingleObjectEx(ops->_hThread, INFINITE, FALSE) != WAIT_OBJECT_0)
return false;
::CloseHandle(ops->_hThread);
ops->_hThread = NULL;
return true;
}
bool ThreadOps::yield() {
static YieldOps yielder;
yielder();
return true;
}
bool ThreadOps::setPriority(ThreadOps* impl, Priority p) {
assert(impl);
#if !defined(ZTHREAD_DISABLE_PRIORITY)
bool result;
// Convert
int n;
switch(p) {
case Low:
n = THREAD_PRIORITY_BELOW_NORMAL;
break;
case High:
n = THREAD_PRIORITY_ABOVE_NORMAL;
break;
case Medium:
default:
n = THREAD_PRIORITY_NORMAL;
}
result = (::SetThreadPriority(impl->_hThread, n) != THREAD_PRIORITY_ERROR_RETURN);
return result;
#else
return true;
#endif
}
bool ThreadOps::getPriority(ThreadOps* impl, Priority& p) {
assert(impl);
bool result = true;
#if !defined(ZTHREAD_DISABLE_PRIORITY)
// Convert to one of the PRIORITY values
switch(::GetThreadPriority(impl->_hThread)) {
case THREAD_PRIORITY_ERROR_RETURN:
result = false;
case THREAD_PRIORITY_BELOW_NORMAL:
p = Low;
break;
case THREAD_PRIORITY_ABOVE_NORMAL:
p = High;
break;
case THREAD_PRIORITY_NORMAL:
default:
p = Medium;
}
#endif
return result;
}
bool ThreadOps::spawn(Runnable* task) {
// Start the thread.
#if defined(HAVE_BEGINTHREADEX)
_hThread = (HANDLE)::_beginthreadex(0, 0, &_dispatch, task, 0, (unsigned int*)&_tid);
#else
_hThread = CreateThread(0, 0, (LPTHREAD_START_ROUTINE)&_dispatch, task, 0, (DWORD*)&_tid);
#endif
return _hThread != NULL;
}
unsigned int __stdcall ThreadOps::_dispatch(void *arg) {
Runnable* task = reinterpret_cast<Runnable*>(arg);
assert(task);
// Run the task from the correct context
task->run();
// Exit the thread
#if defined(HAVE_BEGINTHREADEX)
::_endthreadex(0);
#else
ExitThread(0);
#endif
return 0;
}
}
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