barrier/mt/CThreadRep.cpp

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#include "CThreadRep.h"
#include "CThread.h"
#include "CMutex.h"
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#include "CLock.h"
#include "XThread.h"
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#include "CLog.h"
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#include "IJob.h"
#include <assert.h>
#if defined(CONFIG_PTHREADS)
#include <signal.h>
#define SIGWAKEUP SIGUSR1
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#endif
// FIXME -- temporary exception type
class XThreadUnavailable { };
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#ifndef NDEBUG
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
static void threadDebug(int)
{
if (fork() == 0) abort();
else { wait(0); exit(1); }
}
#endif
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//
// CThreadRep
//
CMutex* CThreadRep::s_mutex = NULL;
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CThreadRep* CThreadRep::s_head = NULL;
CThreadRep::CThreadRep() : m_prev(NULL),
m_next(NULL),
m_refCount(1),
m_job(NULL),
m_userData(NULL)
{
// note -- s_mutex must be locked on entry
assert(s_mutex != NULL);
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// initialize stuff
init();
#if defined(CONFIG_PTHREADS)
// get main thread id
m_thread = pthread_self();
#elif defined(CONFIG_PLATFORM_WIN32)
// get main thread id
m_thread = NULL;
m_id = GetCurrentThreadId();
#endif
// insert ourself into linked list
if (s_head != NULL) {
s_head->m_prev = this;
m_next = s_head;
}
s_head = this;
}
CThreadRep::CThreadRep(IJob* job, void* userData) :
m_prev(NULL),
m_next(NULL),
m_refCount(2), // 1 for us, 1 for thread
m_job(job),
m_userData(userData)
{
assert(m_job != NULL);
assert(s_mutex != NULL);
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// create a thread rep for the main thread if the current thread
// is unknown. note that this might cause multiple "main" threads
// if threads are created external to this library.
getCurrentThreadRep()->unref();
// initialize
init();
// hold mutex while we create the thread
CLock lock(s_mutex);
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// start the thread. throw if it doesn't start.
#if defined(CONFIG_PTHREADS)
int status = pthread_create(&m_thread, NULL, threadFunc, (void*)this);
if (status != 0)
throw XThreadUnavailable();
#elif defined(CONFIG_PLATFORM_WIN32)
unsigned int id;
m_thread = reinterpret_cast<HANDLE>(_beginthreadex(NULL, 0,
threadFunc, (void*)this, 0, &id));
m_id = static_cast<DWORD>(id);
if (m_thread == 0)
throw XThreadUnavailable();
#endif
// insert ourself into linked list
if (s_head != NULL) {
s_head->m_prev = this;
m_next = s_head;
}
s_head = this;
// returning releases the locks, allowing the child thread to run
}
CThreadRep::~CThreadRep()
{
// note -- s_mutex must be locked on entry
// remove ourself from linked list
if (m_prev != NULL) {
m_prev->m_next = m_next;
}
if (m_next != NULL) {
m_next->m_prev = m_prev;
}
if (s_head == this) {
s_head = m_next;
}
// clean up
fini();
}
void CThreadRep::initThreads()
{
if (s_mutex == NULL) {
s_mutex = new CMutex;
#if defined(CONFIG_PTHREADS)
// install SIGWAKEUP handler
struct sigaction act;
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sigemptyset(&act.sa_mask);
# if defined(SA_INTERRUPT)
act.sa_flags = SA_INTERRUPT;
# else
act.sa_flags = 0;
# endif
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act.sa_handler = &threadCancel;
sigaction(SIGWAKEUP, &act, NULL);
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# ifndef NDEBUG
act.sa_handler = &threadDebug;
sigaction(SIGSEGV, &act, NULL);
# endif
#endif
// set signal mask
sigset_t sigset;
sigemptyset(&sigset);
sigaddset(&sigset, SIGWAKEUP);
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#ifndef NDEBUG
sigaddset(&sigset, SIGSEGV);
#endif
pthread_sigmask(SIG_UNBLOCK, &sigset, NULL);
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sigemptyset(&sigset);
sigaddset(&sigset, SIGPIPE);
pthread_sigmask(SIG_BLOCK, &sigset, NULL);
}
}
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void CThreadRep::ref()
{
CLock lock(s_mutex);
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++m_refCount;
}
void CThreadRep::unref()
{
CLock lock(s_mutex);
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if (--m_refCount == 0) {
delete this;
}
}
bool CThreadRep::enableCancel(bool enable)
{
CLock lock(s_mutex);
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const bool old = m_cancellable;
m_cancellable = enable;
return old;
}
bool CThreadRep::isCancellable() const
{
CLock lock(s_mutex);
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return (m_cancellable && !m_cancelling);
}
void* CThreadRep::getResult() const
{
// no lock necessary since thread isn't running
return m_result;
}
void* CThreadRep::getUserData() const
{
// no lock necessary because the value never changes
return m_userData;
}
CThreadRep* CThreadRep::getCurrentThreadRep()
{
assert(s_mutex != NULL);
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#if defined(CONFIG_PTHREADS)
const pthread_t thread = pthread_self();
#elif defined(CONFIG_PLATFORM_WIN32)
const DWORD id = GetCurrentThreadId();
#endif
// lock list while we search
CLock lock(s_mutex);
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// search
CThreadRep* scan = s_head;
while (scan != NULL) {
#if defined(CONFIG_PTHREADS)
if (scan->m_thread == thread) {
break;
}
#elif defined(CONFIG_PLATFORM_WIN32)
if (scan->m_id == id) {
break;
}
#endif
scan = scan->m_next;
}
// create and use main thread rep if thread not found
if (scan == NULL) {
scan = new CThreadRep();
}
// ref for caller
++scan->m_refCount;
return scan;
}
void CThreadRep::doThreadFunc()
{
// default priority is slightly below normal
setPriority(1);
// wait for parent to initialize this object
{ CLock lock(s_mutex); }
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void* result = NULL;
try {
// go
m_job->run();
}
catch (XThreadCancel& e) {
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// client called cancel()
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log((CLOG_DEBUG "caught cancel on thread %p", this));
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}
catch (XThreadExit& e) {
// client called exit()
result = e.m_result;
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log((CLOG_DEBUG "caught exit on thread %p", this));
}
catch (...) {
log((CLOG_DEBUG "exception on thread %p", this));
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// note -- don't catch (...) to avoid masking bugs
delete m_job;
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throw;
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}
// done with job
delete m_job;
// store exit result (no lock necessary because the result will
// not be accessed until m_exit is set)
m_result = result;
}
#if defined(CONFIG_PTHREADS)
#include "CStopwatch.h"
#include <time.h>
void CThreadRep::init()
{
m_result = NULL;
m_cancellable = true;
m_cancelling = false;
m_cancel = false;
m_exit = false;
}
void CThreadRep::fini()
{
// main thread has NULL job
if (m_job != NULL) {
pthread_detach(m_thread);
}
}
void CThreadRep::sleep(double timeout)
{
if (timeout < 0.0)
return;
struct timespec t;
t.tv_sec = (long)timeout;
t.tv_nsec = (long)(1000000000.0 * (timeout - (double)t.tv_sec));
while (nanosleep(&t, &t) < 0)
testCancel();
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}
void CThreadRep::cancel()
{
CLock lock(s_mutex);
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if (m_cancellable && !m_cancelling) {
m_cancel = true;
}
else {
return;
}
// break out of system calls
log((CLOG_DEBUG "cancel thread %p", this));
pthread_kill(m_thread, SIGWAKEUP);
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}
void CThreadRep::testCancel()
{
{
// prevent further cancellation
CLock lock(s_mutex);
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if (!m_cancel || !m_cancellable || m_cancelling)
return;
// update state for cancel
m_cancel = false;
m_cancelling = true;
}
// start cancel
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log((CLOG_DEBUG "throw cancel on thread %p", this));
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throw XThreadCancel();
}
bool CThreadRep::wait(CThreadRep* target, double timeout)
{
if (target == this)
return false;
testCancel();
if (target->isExited())
return true;
if (timeout != 0.0) {
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CStopwatch timer;
do {
sleep(0.05);
testCancel();
if (target->isExited())
return true;
} while (timeout < 0.0 || timer.getTime() <= timeout);
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}
return false;
}
void CThreadRep::setPriority(int)
{
// FIXME
}
bool CThreadRep::isExited() const
{
CLock lock(s_mutex);
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return m_exit;
}
void* CThreadRep::threadFunc(void* arg)
{
CThreadRep* rep = (CThreadRep*)arg;
pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, NULL);
pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, NULL);
// set signal mask
sigset_t sigset;
sigemptyset(&sigset);
sigaddset(&sigset, SIGWAKEUP);
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#ifndef NDEBUG
sigaddset(&sigset, SIGSEGV);
#endif
pthread_sigmask(SIG_UNBLOCK, &sigset, NULL);
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sigemptyset(&sigset);
sigaddset(&sigset, SIGPIPE);
pthread_sigmask(SIG_BLOCK, &sigset, NULL);
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// run thread
rep->doThreadFunc();
{
// mark as terminated
CLock lock(s_mutex);
rep->m_exit = true;
}
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// unref thread
rep->unref();
// terminate the thread
return NULL;
}
void CThreadRep::threadCancel(int)
{
// do nothing
}
#elif defined(CONFIG_PLATFORM_WIN32)
#include <process.h>
void CThreadRep::init()
{
m_result = NULL;
m_cancellable = true;
m_cancelling = false;
m_exit = CreateEvent(NULL, TRUE, FALSE, NULL);
m_cancel = CreateEvent(NULL, TRUE, FALSE, NULL);
}
void CThreadRep::fini()
{
// destroy the events
CloseHandle(m_cancel);
CloseHandle(m_exit);
// close the handle (main thread has a NULL handle)
if (m_thread != NULL) {
CloseHandle(m_thread);
}
}
void CThreadRep::sleep(double timeout)
{
if (isCancellable())
WaitForSingleObject(m_cancel, (DWORD)(1000.0 * timeout));
else
Sleep((DWORD)(1000.0 * timeout));
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}
void CThreadRep::cancel()
{
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log((CLOG_DEBUG "cancel thread %p", this));
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SetEvent(m_cancel);
}
void CThreadRep::testCancel()
{
// poll cancel event. return if not set.
const DWORD result = WaitForSingleObject(getCancelEvent(), 0);
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if (result != WAIT_OBJECT_0)
return;
{
// ignore if disabled or already cancelling
CLock lock(s_mutex);
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if (!m_cancellable || m_cancelling)
return;
// update state for cancel
m_cancelling = true;
ResetEvent(m_cancel);
}
// start cancel
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log((CLOG_DEBUG "throw cancel on thread %p", this));
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throw XThreadCancel();
}
bool CThreadRep::wait(CThreadRep* target, double timeout)
{
// get the current thread. if it's the same as the target thread
// then the thread is waiting on itself.
CRefCountedPtr<CThreadRep> currentRep(CThreadRep::getCurrentThreadRep());
if (target == this)
return false;
// is cancellation enabled?
const DWORD n = (isCancellable() ? 2 : 1);
// convert timeout
DWORD t;
if (timeout < 0.0)
t = INFINITE;
else
t = (DWORD)(1000.0 * timeout);
// wait for this thread to be cancelled or for the target thread to
// terminate.
HANDLE handles[2];
handles[0] = target->getExitEvent();
handles[1] = m_cancel;
DWORD result = WaitForMultipleObjects(n, handles, FALSE, t);
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// cancel takes priority
if (n == 2 && result != WAIT_OBJECT_0 + 1 &&
WaitForSingleObject(handles[1], 0) == WAIT_OBJECT_0)
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result = WAIT_OBJECT_0 + 1;
// handle result
switch (result) {
case WAIT_OBJECT_0 + 0:
// target thread terminated
return true;
case WAIT_OBJECT_0 + 1:
// this thread was cancelled. does not return.
testCancel();
default:
// error
return false;
}
}
void CThreadRep::setPriority(int n)
{
if (n < 0) {
switch (-n) {
case 1: n = THREAD_PRIORITY_ABOVE_NORMAL; break;
default: n = THREAD_PRIORITY_HIGHEST; break;
}
}
else {
switch (n) {
case 0: n = THREAD_PRIORITY_NORMAL; break;
case 1: n = THREAD_PRIORITY_BELOW_NORMAL; break;
case 2: n = THREAD_PRIORITY_LOWEST; break;
default: n = THREAD_PRIORITY_IDLE; break;
}
}
SetThreadPriority(m_thread, n);
}
HANDLE CThreadRep::getExitEvent() const
{
// no lock necessary because the value never changes
return m_exit;
}
HANDLE CThreadRep::getCancelEvent() const
{
// no lock necessary because the value never changes
return m_cancel;
}
unsigned int __stdcall CThreadRep::threadFunc(void* arg)
{
CThreadRep* rep = (CThreadRep*)arg;
// initialize OLE
const HRESULT hr = OleInitialize(NULL);
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// run thread
rep->doThreadFunc();
// close OLE
if (!FAILED(hr)) {
OleUninitialize();
}
// signal termination
SetEvent(rep->m_exit);
// unref thread
rep->unref();
// terminate the thread
return 0;
}
#endif