// Licence: wxWindows licence
/////////////////////////////////////////////////////////////////////////////
-#ifdef __GNUG__
+#if defined(__GNUG__) && !defined(NO_GCC_PRAGMA)
#pragma implementation "thread.h"
#endif
// calling wxMutexGuiEnter()
static DWORD gs_idMainThread = 0;
-// if it's FALSE, some secondary thread is holding the GUI lock
-static bool gs_bGuiOwnedByMainThread = TRUE;
+// if it's false, some secondary thread is holding the GUI lock
+static bool gs_bGuiOwnedByMainThread = true;
// critical section which controls access to all GUI functions: any secondary
// thread (i.e. except the main one) must enter this crit section before doing
// critical section which protects gs_nWaitingForGui variable
static wxCriticalSection *gs_critsectWaitingForGui = NULL;
+// critical section which serializes WinThreadStart() and WaitForTerminate()
+// (this is a potential bottleneck, we use a single crit sect for all threads
+// in the system, but normally time spent inside it should be quite short)
+static wxCriticalSection *gs_critsectThreadDelete = NULL;
+
// number of threads waiting for GUI in wxMutexGuiEnter()
static size_t gs_nWaitingForGui = 0;
// are we waiting for a thread termination?
-static bool gs_waitingForThread = FALSE;
+static bool gs_waitingForThread = false;
// ============================================================================
// Windows implementation of thread and related classes
m_mutex = ::CreateMutex
(
NULL, // default secutiry attributes
- FALSE, // not initially locked
+ false, // not initially locked
NULL // no name
);
wxSemaphoreInternal::wxSemaphoreInternal(int initialcount, int maxcount)
{
-#ifndef __WXWINCE__
+#if !defined(_WIN32_WCE) || (_WIN32_WCE >= 300)
if ( maxcount == 0 )
{
// make it practically infinite
wxSemaError wxSemaphoreInternal::Post()
{
-#ifndef __WXWINCE__
+#if !defined(_WIN32_WCE) || (_WIN32_WCE >= 300)
if ( !::ReleaseSemaphore(m_semaphore, 1, NULL /* ptr to previous count */) )
#endif
{
return wxSEMA_NO_ERROR;
}
-// --------------------------------------------------------------------------
-// wxCondition
-// --------------------------------------------------------------------------
-
-// Win32 doesn't have explicit support for the POSIX condition variables and
-// the Win32 events have quite different semantics, so we reimplement the
-// conditions from scratch using the mutexes and semaphores
-class wxConditionInternal
-{
-public:
- wxConditionInternal(wxMutex& mutex);
-
- bool IsOk() const { return m_mutex.IsOk() && m_semaphore.IsOk(); }
-
- wxCondError Wait();
- wxCondError WaitTimeout(unsigned long milliseconds);
-
- wxCondError Signal();
- wxCondError Broadcast();
-
-private:
- // the number of threads currently waiting for this condition
- LONG m_numWaiters;
-
- // the critical section protecting m_numWaiters
- wxCriticalSection m_csWaiters;
-
- wxMutex& m_mutex;
- wxSemaphore m_semaphore;
-};
-
-wxConditionInternal::wxConditionInternal(wxMutex& mutex)
- : m_mutex(mutex)
-{
- // another thread can't access it until we return from ctor, so no need to
- // protect access to m_numWaiters here
- m_numWaiters = 0;
-}
-
-wxCondError wxConditionInternal::Wait()
-{
- // increment the number of waiters
- ::InterlockedIncrement(&m_numWaiters);
-
- m_mutex.Unlock();
-
- // a potential race condition can occur here
- //
- // after a thread increments nwaiters, and unlocks the mutex and before the
- // semaphore.Wait() is called, if another thread can cause a signal to be
- // generated
- //
- // this race condition is handled by using a semaphore and incrementing the
- // semaphore only if 'nwaiters' is greater that zero since the semaphore,
- // can 'remember' signals the race condition will not occur
-
- // wait ( if necessary ) and decrement semaphore
- wxSemaError err = m_semaphore.Wait();
- m_mutex.Lock();
-
- return err == wxSEMA_NO_ERROR ? wxCOND_NO_ERROR : wxCOND_MISC_ERROR;
-}
-
-wxCondError wxConditionInternal::WaitTimeout(unsigned long milliseconds)
-{
- ::InterlockedIncrement(&m_numWaiters);
-
- m_mutex.Unlock();
-
- // a race condition can occur at this point in the code
- //
- // please see the comments in Wait(), for details
-
- wxSemaError err = m_semaphore.WaitTimeout(milliseconds);
-
- if ( err == wxSEMA_BUSY )
- {
- // another potential race condition exists here it is caused when a
- // 'waiting' thread timesout, and returns from WaitForSingleObject, but
- // has not yet decremented 'nwaiters'.
- //
- // at this point if another thread calls signal() then the semaphore
- // will be incremented, but the waiting thread will miss it.
- //
- // to handle this particular case, the waiting thread calls
- // WaitForSingleObject again with a timeout of 0, after locking
- // 'nwaiters_mutex'. this call does not block because of the zero
- // timeout, but will allow the waiting thread to catch the missed
- // signals.
- wxCriticalSectionLocker lock(m_csWaiters);
-
- err = m_semaphore.WaitTimeout(0);
-
- if ( err != wxSEMA_NO_ERROR )
- {
- m_numWaiters--;
- }
- }
-
- m_mutex.Lock();
-
- return err == wxSEMA_NO_ERROR ? wxCOND_NO_ERROR : wxCOND_MISC_ERROR;
-}
-
-wxCondError wxConditionInternal::Signal()
-{
- wxCriticalSectionLocker lock(m_csWaiters);
-
- if ( m_numWaiters > 0 )
- {
- // increment the semaphore by 1
- if ( m_semaphore.Post() != wxSEMA_NO_ERROR )
- return wxCOND_MISC_ERROR;
-
- m_numWaiters--;
- }
-
- return wxCOND_NO_ERROR;
-}
-
-wxCondError wxConditionInternal::Broadcast()
-{
- wxCriticalSectionLocker lock(m_csWaiters);
-
- while ( m_numWaiters > 0 )
- {
- if ( m_semaphore.Post() != wxSEMA_NO_ERROR )
- return wxCOND_MISC_ERROR;
-
- m_numWaiters--;
- }
-
- return wxCOND_NO_ERROR;
-}
-
// ----------------------------------------------------------------------------
// wxThread implementation
// ----------------------------------------------------------------------------
class wxThreadInternal
{
public:
- wxThreadInternal()
+ wxThreadInternal(wxThread *thread)
{
+ m_thread = thread;
m_hThread = 0;
m_state = STATE_NEW;
m_priority = WXTHREAD_DEFAULT_PRIORITY;
+ m_nRef = 1;
}
~wxThreadInternal()
// wait for the thread to terminate, either by itself, or by asking it
// (politely, this is not Kill()!) to do it
- wxThreadError WaitForTerminate(bool shouldCancel,
- wxCriticalSection& cs,
- wxThread::ExitCode *pRc);
+ wxThreadError WaitForTerminate(wxCriticalSection& cs,
+ wxThread::ExitCode *pRc,
+ wxThread *threadToDelete = NULL);
// kill the thread unconditionally
wxThreadError Kill();
// thread function
static THREAD_RETVAL THREAD_CALLCONV WinThreadStart(void *thread);
+ void KeepAlive()
+ {
+ if ( m_thread->IsDetached() )
+ ::InterlockedIncrement(&m_nRef);
+ }
+
+ void LetDie()
+ {
+ if ( m_thread->IsDetached() && !::InterlockedDecrement(&m_nRef) )
+ delete m_thread;
+ }
+
private:
+ // the thread we're associated with
+ wxThread *m_thread;
+
HANDLE m_hThread; // handle of the thread
wxThreadState m_state; // state, see wxThreadState enum
unsigned int m_priority; // thread priority in "wx" units
DWORD m_tid; // thread id
+ // number of threads which need this thread to remain alive, when the count
+ // reaches 0 we kill the owning wxThread -- and die ourselves with it
+ LONG m_nRef;
+
DECLARE_NO_COPY_CLASS(wxThreadInternal)
};
+// small class which keeps a thread alive during its lifetime
+class wxThreadKeepAlive
+{
+public:
+ wxThreadKeepAlive(wxThreadInternal& thrImpl) : m_thrImpl(thrImpl)
+ { m_thrImpl.KeepAlive(); }
+ ~wxThreadKeepAlive()
+ { m_thrImpl.LetDie(); }
+
+private:
+ wxThreadInternal& m_thrImpl;
+};
+
+
THREAD_RETVAL THREAD_CALLCONV wxThreadInternal::WinThreadStart(void *param)
{
THREAD_RETVAL rc;
- bool wasCancelled;
+
+ wxThread * const thread = (wxThread *)param;
// first of all, check whether we hadn't been cancelled already and don't
// start the user code at all then
- wxThread *thread = (wxThread *)param;
- if ( thread->m_internal->GetState() == STATE_EXITED )
+ bool isExited = (thread->m_internal->GetState() == STATE_EXITED);
+
+ if ( isExited )
{
rc = (THREAD_RETVAL)-1;
- wasCancelled = TRUE;
}
else // do run thread
{
}
rc = (THREAD_RETVAL)thread->Entry();
-
- // enter m_critsect before changing the thread state
- thread->m_critsect.Enter();
- wasCancelled = thread->m_internal->GetState() == STATE_CANCELED;
- thread->m_internal->SetState(STATE_EXITED);
- thread->m_critsect.Leave();
}
thread->OnExit();
- // if the thread was cancelled (from Delete()), then its handle is still
- // needed there
- if ( thread->IsDetached() && !wasCancelled )
+ // save IsDetached because thread object can be deleted by joinable
+ // threads after state is changed to STATE_EXITED.
+ bool isDetached = thread->IsDetached();
+
+ if (!isExited)
{
- // auto delete
- delete thread;
+ // enter m_critsect before changing the thread state
+ wxCriticalSectionLocker lock(thread->m_critsect);
+ thread->m_internal->SetState(STATE_EXITED);
}
- //else: the joinable threads handle will be closed when Wait() is done
+
+ // the thread may delete itself now if it wants, we don't need it any more
+ if (isDetached) thread->m_internal->LetDie();
return rc;
}
{
wxLogSysError(_("Can't create thread"));
- return FALSE;
+ return false;
}
if ( m_priority != WXTHREAD_DEFAULT_PRIORITY )
SetPriority(m_priority);
}
- return TRUE;
+ return true;
}
wxThreadError wxThreadInternal::Kill()
}
wxThreadError
-wxThreadInternal::WaitForTerminate(bool shouldCancel,
- wxCriticalSection& cs,
- wxThread::ExitCode *pRc)
+wxThreadInternal::WaitForTerminate(wxCriticalSection& cs,
+ wxThread::ExitCode *pRc,
+ wxThread *threadToDelete)
{
+ // prevent the thread C++ object from disappearing as long as we are using
+ // it here
+ wxThreadKeepAlive keepAlive(*this);
+
+
+ // we may either wait passively for the thread to terminate (when called
+ // from Wait()) or ask it to terminate (when called from Delete())
+ bool shouldDelete = threadToDelete != NULL;
+
wxThread::ExitCode rc = 0;
// Delete() is always safe to call, so consider all possible states
// we might need to resume the thread, but we might also not need to cancel
// it if it doesn't run yet
- bool shouldResume = FALSE,
- isRunning = FALSE;
+ bool shouldResume = false,
+ isRunning = false;
// check if the thread already started to run
{
if ( m_state == STATE_NEW )
{
- if ( shouldCancel )
+ if ( shouldDelete )
{
- // WinThreadStart() will see it and terminate immediately, no need
- // to cancel the thread - but we still need to resume it to let it
- // run
+ // WinThreadStart() will see it and terminate immediately, no
+ // need to cancel the thread -- but we still need to resume it
+ // to let it run
m_state = STATE_EXITED;
Resume(); // it knows about STATE_EXITED special case
- shouldCancel = FALSE;
+ shouldDelete = false;
}
- isRunning = TRUE;
+ isRunning = true;
- // shouldResume is correctly set to FALSE here
+ // shouldResume is correctly set to false here
+ }
+ else if ( m_state == STATE_EXITED )
+ {
+ return wxTHREAD_NOT_RUNNING;
}
- else
+ else // running (but maybe paused or cancelled)
{
shouldResume = m_state == STATE_PAUSED;
}
if ( shouldResume )
Resume();
- // does is still run?
+ // is it still running?
if ( isRunning || m_state == STATE_RUNNING )
{
if ( wxThread::IsMain() )
{
// set flag for wxIsWaitingForThread()
- gs_waitingForThread = TRUE;
+ gs_waitingForThread = true;
}
// ask the thread to terminate
- if ( shouldCancel )
+ if ( shouldDelete )
{
wxCriticalSectionLocker lock(cs);
// process the Windows messages that result from these functions
// (note that even in console applications we might have to process
// messages if we use wxExecute() or timers or ...)
- DWORD result = 0; // suppress warnings from broken compilers
+ DWORD result wxDUMMY_INITIALIZE(0);
do
{
if ( wxThread::IsMain() )
(
1, // number of objects to wait for
&m_hThread, // the objects
- FALSE, // don't wait for all objects
+ false, // don't wait for all objects
INFINITE, // no timeout
QS_ALLINPUT | // return as soon as there are any events
QS_ALLPOSTMESSAGE
break;
case WAIT_OBJECT_0 + 1:
- // new message arrived, process it
+ // new message arrived, process it -- but only if we're the
+ // main thread as we don't support processing messages in
+ // the other ones
+ //
+ // NB: we still must include QS_ALLINPUT even when waiting
+ // in a secondary thread because if it had created some
+ // window somehow (possible not even using wxWindows)
+ // the system might dead lock then
+ if ( wxThread::IsMain() )
{
// it looks that sometimes WAIT_OBJECT_0 + 1 is
// returned but there are no messages in the thread
if ( wxThread::IsMain() )
{
- gs_waitingForThread = FALSE;
+ gs_waitingForThread = false;
}
}
// although the thread might be already in the EXITED state it might not
// have terminated yet and so we are not sure that it has actually
// terminated if the "if" above hadn't been taken
- do
+ for ( ;; )
{
if ( !::GetExitCodeThread(m_hThread, (LPDWORD)&rc) )
{
wxLogLastError(wxT("GetExitCodeThread"));
rc = (wxThread::ExitCode)-1;
+
+ break;
}
- } while ( (DWORD)rc == STILL_ACTIVE );
+
+ if ( (DWORD)rc != STILL_ACTIVE )
+ break;
+
+ // give the other thread some time to terminate, otherwise we may be
+ // starving it
+ ::Sleep(1);
+ }
if ( pRc )
*pRc = rc;
+ // we don't need the thread handle any more in any case
+ Free();
+
+
return rc == (wxThread::ExitCode)-1 ? wxTHREAD_MISC_ERROR
: wxTHREAD_NO_ERROR;
}
{
wxLogSysError(_("Can not suspend thread %x"), m_hThread);
- return FALSE;
+ return false;
}
m_state = STATE_PAUSED;
- return TRUE;
+ return true;
}
bool wxThreadInternal::Resume()
{
wxLogSysError(_("Can not resume thread %x"), m_hThread);
- return FALSE;
+ return false;
}
// don't change the state from STATE_EXITED because it's special and means
m_state = STATE_RUNNING;
}
- return TRUE;
+ return true;
}
// static functions
return ::GetCurrentThreadId() == gs_idMainThread;
}
-#ifdef Yield
-#undef Yield
-#endif
-
void wxThread::Yield()
{
// 0 argument to Sleep() is special and means to just give away the rest of
{
wxLogLastError(_T("GetProcessAffinityMask"));
- return FALSE;
+ return false;
}
// how many CPUs have we got?
{
wxLogDebug(_T("bad level %u in wxThread::SetConcurrency()"), level);
- return FALSE;
+ return false;
}
// set it: we can't link to SetProcessAffinityMask() because it doesn't
if ( !pfnSetProcessAffinityMask )
{
// msg given above - do it only once
- return FALSE;
+ return false;
}
if ( pfnSetProcessAffinityMask(hProcess, dwProcMask) == 0 )
{
wxLogLastError(_T("SetProcessAffinityMask"));
- return FALSE;
+ return false;
}
#endif
- return TRUE;
+ return true;
}
// ctor and dtor
wxThread::wxThread(wxThreadKind kind)
{
- m_internal = new wxThreadInternal();
+ m_internal = new wxThreadInternal(this);
m_isDetached = kind == wxTHREAD_DETACHED;
}
ExitCode rc = (ExitCode)-1;
- (void)m_internal->WaitForTerminate(false, m_critsect, &rc);
-
- m_internal->Free();
-
- wxCriticalSectionLocker lock(m_critsect);
- m_internal->SetState(STATE_EXITED);
+ (void)m_internal->WaitForTerminate(m_critsect, &rc);
return rc;
}
wxThreadError wxThread::Delete(ExitCode *pRc)
{
- wxThreadError rc = m_internal->WaitForTerminate(true, m_critsect, pRc);
-
- if ( IsDetached() )
- {
- delete this;
- }
- else // joinable
- {
- // update the status of the joinable thread
- wxCriticalSectionLocker lock(m_critsect);
- m_internal->SetState(STATE_EXITED);
- }
-
- return rc;
+ return m_internal->WaitForTerminate(m_critsect, pRc, this);
}
wxThreadError wxThread::Kill()
// words, this should never happen
wxLogSysError(_("Thread module initialization failed: impossible to allocate index in thread local storage"));
- return FALSE;
+ return false;
}
// main thread doesn't have associated wxThread object, so store 0 in the
wxLogSysError(_("Thread module initialization failed: can not store value in thread local storage"));
- return FALSE;
+ return false;
}
gs_critsectWaitingForGui = new wxCriticalSection();
gs_critsectGui = new wxCriticalSection();
gs_critsectGui->Enter();
+ gs_critsectThreadDelete = new wxCriticalSection;
+
// no error return for GetCurrentThreadId()
gs_idMainThread = ::GetCurrentThreadId();
- return TRUE;
+ return true;
}
void wxThreadModule::OnExit()
wxLogLastError(wxT("TlsFree failed."));
}
+ delete gs_critsectThreadDelete;
+ gs_critsectThreadDelete = NULL;
+
if ( gs_critsectGui )
{
gs_critsectGui->Leave();
if ( wxThread::IsMain() )
{
- gs_bGuiOwnedByMainThread = FALSE;
+ gs_bGuiOwnedByMainThread = false;
}
else
{
{
gs_critsectGui->Enter();
- gs_bGuiOwnedByMainThread = TRUE;
+ gs_bGuiOwnedByMainThread = true;
}
//else: already have it, nothing to do
}
projects / wxWidgets.git / blobdiff