X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/7ab9bf9f2d2e6962b90616399bd89fd609d44741..9f4de6b2cf06f53a98b28f53640f3b9ec8cf4182:/src/msw/thread.cpp?ds=sidebyside diff --git a/src/msw/thread.cpp b/src/msw/thread.cpp index a7aff134f2..e2c76f9389 100644 --- a/src/msw/thread.cpp +++ b/src/msw/thread.cpp @@ -26,7 +26,7 @@ #endif #ifndef WX_PRECOMP - #include "wx/wx.h" +# include "wx/wx.h" #endif #if wxUSE_THREADS @@ -36,13 +36,51 @@ #include "wx/module.h" #include "wx/thread.h" +#ifdef Yield +# undef Yield +#endif + // must have this symbol defined to get _beginthread/_endthread declarations #ifndef _MT #define _MT #endif -#if defined(__VISUALC__) || (defined(__BORLANDC__) && (__BORLANDC__ >= 0x500)) +#if defined(__BORLANDC__) + #if !defined(__MT__) + // I can't set -tWM in the IDE (anyone?) so have to do this + #define __MT__ + #endif + + #if !defined(__MFC_COMPAT__) + // Needed to know about _beginthreadex etc.. + #define __MFC_COMPAT__ + #endif +#endif // BC++ + +// define wxUSE_BEGIN_THREAD if the compiler has _beginthreadex() function +// which should be used instead of Win32 ::CreateThread() if possible +#if defined(__VISUALC__) || \ + (defined(__BORLANDC__) && (__BORLANDC__ >= 0x500)) || \ + (defined(__GNUG__) && defined(__MSVCRT__)) || \ + defined(__WATCOMC__) + + #undef wxUSE_BEGIN_THREAD + #define wxUSE_BEGIN_THREAD +#endif + +#ifdef wxUSE_BEGIN_THREAD + // this is where _beginthreadex() is declared #include + + // the return type of the thread function entry point + typedef unsigned THREAD_RETVAL; + + // the calling convention of the thread function entry point + #define THREAD_CALLCONV __stdcall +#else + // the settings for CreateThread() + typedef DWORD THREAD_RETVAL; + #define THREAD_CALLCONV WINAPI #endif // ---------------------------------------------------------------------------- @@ -108,7 +146,7 @@ public: } } - ~wxMutexInternal() { if ( m_mutex ) CloseHandle(m_mutex); } + ~wxMutexInternal() { if ( m_mutex ) ::CloseHandle(m_mutex); } public: HANDLE m_mutex; @@ -185,58 +223,272 @@ wxMutexError wxMutex::Unlock() return wxMUTEX_NO_ERROR; } -// ---------------------------------------------------------------------------- -// wxCondition implementation -// ---------------------------------------------------------------------------- +// ========================================================================== +// wxSemaphore +// ========================================================================== -class wxConditionInternal +// -------------------------------------------------------------------------- +// wxSemaphoreInternal +// -------------------------------------------------------------------------- + +class wxSemaphoreInternal { public: - wxConditionInternal() + wxSemaphoreInternal( int initialcount = 0, int maxcount = 0 ); + ~wxSemaphoreInternal(); + + void Wait(); + bool TryWait(); + + bool Wait( unsigned long timeout_millis ); + + void Post(); + +private: + HANDLE m_semaphore; +}; + +wxSemaphoreInternal::wxSemaphoreInternal( int initialcount, int maxcount ) +{ + if ( maxcount == 0 ) { - event = ::CreateEvent( - NULL, // default secutiry - FALSE, // not manual reset - FALSE, // nonsignaled initially - NULL // nameless event - ); - if ( !event ) - { - wxLogSysError(_("Can not create event object.")); - } - waiters = 0; + // make it practically infinite + maxcount = INT_MAX; + } + + m_semaphore = ::CreateSemaphore( NULL, initialcount, maxcount, NULL ); + if ( !m_semaphore ) + { + wxLogLastError(_T("CreateSemaphore()")); } +} + +wxSemaphoreInternal::~wxSemaphoreInternal() +{ + CloseHandle( m_semaphore ); +} + +void wxSemaphoreInternal::Wait() +{ + if ( ::WaitForSingleObject( m_semaphore, INFINITE ) != WAIT_OBJECT_0 ) + { + wxLogLastError(_T("WaitForSingleObject")); + } +} + +bool wxSemaphoreInternal::TryWait() +{ + return Wait(0); +} - bool Wait(DWORD timeout) +bool wxSemaphoreInternal::Wait( unsigned long timeout_millis ) +{ + DWORD result = ::WaitForSingleObject( m_semaphore, timeout_millis ); + + switch ( result ) { - waiters++; + case WAIT_OBJECT_0: + return TRUE; + + case WAIT_TIMEOUT: + break; - // FIXME this should be MsgWaitForMultipleObjects() as well probably - DWORD rc = ::WaitForSingleObject(event, timeout); + default: + wxLogLastError(_T("WaitForSingleObject()")); + } - waiters--; + return FALSE; +} - return rc != WAIT_TIMEOUT; +void wxSemaphoreInternal::Post() +{ + if ( !::ReleaseSemaphore( m_semaphore, 1, NULL ) ) + { + wxLogLastError(_T("ReleaseSemaphore")); } +} + +// -------------------------------------------------------------------------- +// wxSemaphore +// -------------------------------------------------------------------------- + +wxSemaphore::wxSemaphore( int initialcount, int maxcount ) +{ + m_internal = new wxSemaphoreInternal( initialcount, maxcount ); +} + +wxSemaphore::~wxSemaphore() +{ + delete m_internal; +} + +void wxSemaphore::Wait() +{ + m_internal->Wait(); +} + +bool wxSemaphore::TryWait() +{ + return m_internal->TryWait(); +} + +bool wxSemaphore::Wait( unsigned long timeout_millis ) +{ + return m_internal->Wait( timeout_millis ); +} + +void wxSemaphore::Post() +{ + m_internal->Post(); +} + + +// ========================================================================== +// wxCondition +// ========================================================================== + +// -------------------------------------------------------------------------- +// wxConditionInternal +// -------------------------------------------------------------------------- + +class wxConditionInternal +{ +public: + wxConditionInternal(wxMutex& mutex); + + void Wait(); - ~wxConditionInternal() + bool Wait( unsigned long timeout_millis ); + + void Signal(); + + void Broadcast(); + +private: + int m_numWaiters; + wxMutex m_mutexNumWaiters; + + wxMutex& m_mutex; + + wxSemaphore m_semaphore; + + DECLARE_NO_COPY_CLASS(wxConditionInternal) +}; + +wxConditionInternal::wxConditionInternal(wxMutex& mutex) + : m_mutex(mutex) +{ + + m_numWaiters = 0; +} + +void wxConditionInternal::Wait() +{ + // increment the number of waiters + m_mutexNumWaiters.Lock(); + m_numWaiters++; + m_mutexNumWaiters.Unlock(); + + 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 + m_semaphore.Wait(); + + m_mutex.Lock(); +} + +bool wxConditionInternal::Wait( unsigned long timeout_millis ) +{ + m_mutexNumWaiters.Lock(); + m_numWaiters++; + m_mutexNumWaiters.Unlock(); + + m_mutex.Unlock(); + + // a race condition can occur at this point in the code + // + // please see the comments in Wait(), for details + + bool success = TRUE; + + bool result = m_semaphore.Wait( timeout_millis ); + + if ( !result ) { - if ( event ) + // 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. + m_mutexNumWaiters.Lock(); + result = m_semaphore.Wait( 0 ); + + if ( !result ) { - if ( !::CloseHandle(event) ) - { - wxLogLastError("CloseHandle(event)"); - } + m_numWaiters--; + success = FALSE; } + + m_mutexNumWaiters.Unlock(); } - HANDLE event; - int waiters; -}; + m_mutex.Lock(); + + return success; +} + +void wxConditionInternal::Signal() +{ + m_mutexNumWaiters.Lock(); + + if ( m_numWaiters > 0 ) + { + // increment the semaphore by 1 + m_semaphore.Post(); + + m_numWaiters--; + } + + m_mutexNumWaiters.Unlock(); +} + +void wxConditionInternal::Broadcast() +{ + m_mutexNumWaiters.Lock(); + + while ( m_numWaiters > 0 ) + { + m_semaphore.Post(); + m_numWaiters--; + } + + m_mutexNumWaiters.Unlock(); +} + +// ---------------------------------------------------------------------------- +// wxCondition implementation +// ---------------------------------------------------------------------------- -wxCondition::wxCondition() +wxCondition::wxCondition(wxMutex& mutex) { - m_internal = new wxConditionInternal; + m_internal = new wxConditionInternal( mutex ); } wxCondition::~wxCondition() @@ -246,37 +498,22 @@ wxCondition::~wxCondition() void wxCondition::Wait() { - (void)m_internal->Wait(INFINITE); + m_internal->Wait(); } -bool wxCondition::Wait(unsigned long sec, - unsigned long nsec) +bool wxCondition::Wait( unsigned long timeout_millis ) { - return m_internal->Wait(sec*1000 + nsec/1000000); + return m_internal->Wait(timeout_millis); } void wxCondition::Signal() { - // set the event to signaled: if a thread is already waiting on it, it will - // be woken up, otherwise the event will remain in the signaled state until - // someone waits on it. In any case, the system will return it to a non - // signalled state afterwards. If multiple threads are waiting, only one - // will be woken up. - if ( !::SetEvent(m_internal->event) ) - { - wxLogLastError("SetEvent"); - } + m_internal->Signal(); } void wxCondition::Broadcast() { - // this works because all these threads are already waiting and so each - // SetEvent() inside Signal() is really a PulseEvent() because the event - // state is immediately returned to non-signaled - for ( int i = 0; i < m_internal->waiters; i++ ) - { - Signal(); - } + m_internal->Broadcast(); } // ---------------------------------------------------------------------------- @@ -285,8 +522,14 @@ void wxCondition::Broadcast() wxCriticalSection::wxCriticalSection() { - wxASSERT_MSG( sizeof(CRITICAL_SECTION) <= sizeof(m_buffer), +#ifdef __WXDEBUG__ + // Done this way to stop warnings during compilation about statement + // always being FALSE + int csSize = sizeof(CRITICAL_SECTION); + int bSize = sizeof(m_buffer); + wxASSERT_MSG( csSize <= bSize, _T("must increase buffer size in wx/thread.h") ); +#endif ::InitializeCriticalSection((CRITICAL_SECTION *)m_buffer); } @@ -334,7 +577,7 @@ public: { if ( !::CloseHandle(m_hThread) ) { - wxLogLastError("CloseHandle(thread)"); + wxLogLastError(wxT("CloseHandle(thread)")); } m_hThread = 0; @@ -342,7 +585,7 @@ public: } // create a new (suspended) thread (for the given thread object) - bool Create(wxThread *thread); + bool Create(wxThread *thread, unsigned int stackSize); // suspend/resume/terminate bool Suspend(); @@ -362,7 +605,7 @@ public: DWORD GetId() const { return m_tid; } // thread function - static DWORD WinThreadStart(wxThread *thread); + static THREAD_RETVAL THREAD_CALLCONV WinThreadStart(void *thread); private: HANDLE m_hThread; // handle of the thread @@ -371,33 +614,41 @@ private: DWORD m_tid; // thread id }; -DWORD wxThreadInternal::WinThreadStart(wxThread *thread) +THREAD_RETVAL THREAD_CALLCONV wxThreadInternal::WinThreadStart(void *param) { - // first of all, check whether we hadn't been cancelled already + THREAD_RETVAL rc; + bool wasCancelled; + + // 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 ) { - return (DWORD)-1; + rc = (THREAD_RETVAL)-1; + wasCancelled = TRUE; } - - // store the thread object in the TLS - if ( !::TlsSetValue(gs_tlsThisThread, thread) ) + else // do run thread { - wxLogSysError(_("Can not start thread: error writing TLS.")); + // store the thread object in the TLS + if ( !::TlsSetValue(gs_tlsThisThread, thread) ) + { + wxLogSysError(_("Can not start thread: error writing TLS.")); - return (DWORD)-1; - } + return (DWORD)-1; + } - DWORD rc = (DWORD)thread->Entry(); + rc = (THREAD_RETVAL)thread->Entry(); - // enter m_critsect before changing the thread state - thread->m_critsect.Enter(); - bool wasCancelled = thread->m_internal->GetState() == STATE_CANCELED; - thread->m_internal->SetState(STATE_EXITED); - thread->m_critsect.Leave(); + // 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 it the handle is still + // if the thread was cancelled (from Delete()), then its handle is still // needed there if ( thread->IsDetached() && !wasCancelled ) { @@ -437,31 +688,40 @@ void wxThreadInternal::SetPriority(unsigned int priority) } } -bool wxThreadInternal::Create(wxThread *thread) +bool wxThreadInternal::Create(wxThread *thread, unsigned int stackSize) { // for compilers which have it, we should use C RTL function for thread // creation instead of Win32 API one because otherwise we will have memory // leaks if the thread uses C RTL (and most threads do) -#if defined(__VISUALC__) || (defined(__BORLANDC__) && (__BORLANDC__ >= 0x500)) - typedef unsigned (__stdcall *RtlThreadStart)(void *); - - m_hThread = (HANDLE)_beginthreadex(NULL, 0, - (RtlThreadStart) - wxThreadInternal::WinThreadStart, - thread, CREATE_SUSPENDED, - (unsigned int *)&m_tid); -#else // !VC++ +#ifdef wxUSE_BEGIN_THREAD + + // Watcom is reported to not like 0 stack size (which means "use default" + // for the other compilers and is also the default value for stackSize) +#ifdef __WATCOMC__ + if ( !stackSize ) + stackSize = 10240; +#endif // __WATCOMC__ + + m_hThread = (HANDLE)_beginthreadex + ( + NULL, // default security + stackSize, + wxThreadInternal::WinThreadStart, // entry point + thread, + CREATE_SUSPENDED, + (unsigned int *)&m_tid + ); +#else // compiler doesn't have _beginthreadex m_hThread = ::CreateThread ( NULL, // default security - 0, // default stack size - (LPTHREAD_START_ROUTINE) // thread entry point - wxThreadInternal::WinThreadStart, // + stackSize, // stack size + wxThreadInternal::WinThreadStart, // thread entry point (LPVOID)thread, // parameter CREATE_SUSPENDED, // flags &m_tid // [out] thread id ); -#endif // VC++/!VC++ +#endif // _beginthreadex/CreateThread if ( m_hThread == NULL ) { @@ -503,7 +763,13 @@ bool wxThreadInternal::Resume() return FALSE; } - m_state = STATE_RUNNING; + // don't change the state from STATE_EXITED because it's special and means + // we are going to terminate without running any user code - if we did it, + // the codei n Delete() wouldn't work + if ( m_state != STATE_EXITED ) + { + m_state = STATE_RUNNING; + } return TRUE; } @@ -555,6 +821,11 @@ int wxThread::GetCPUCount() return si.dwNumberOfProcessors; } +unsigned long wxThread::GetCurrentId() +{ + return (unsigned long)::GetCurrentThreadId(); +} + bool wxThread::SetConcurrency(size_t level) { wxASSERT_MSG( IsMain(), _T("should only be called from the main thread") ); @@ -626,18 +897,12 @@ bool wxThread::SetConcurrency(size_t level) if ( hModKernel ) { pfnSetProcessAffinityMask = (SETPROCESSAFFINITYMASK) - ::GetProcAddress(hModKernel, -#if defined(__BORLANDC__) && (__BORLANDC__ <= 0x520) - "SetProcessAffinityMask"); -#else - _T("SetProcessAffinityMask")); -#endif + ::GetProcAddress(hModKernel, "SetProcessAffinityMask"); } // we've discovered a MT version of Win9x! wxASSERT_MSG( pfnSetProcessAffinityMask, - _T("this system has several CPUs but no " - "SetProcessAffinityMask function?") ); + _T("this system has several CPUs but no SetProcessAffinityMask function?") ); } if ( !pfnSetProcessAffinityMask ) @@ -674,11 +939,11 @@ wxThread::~wxThread() // create/start thread // ------------------- -wxThreadError wxThread::Create() +wxThreadError wxThread::Create(unsigned int stackSize) { wxCriticalSectionLocker lock(m_critsect); - if ( !m_internal->Create(this) ) + if ( !m_internal->Create(this, stackSize) ) return wxTHREAD_NO_RESOURCE; return wxTHREAD_NO_ERROR; @@ -740,29 +1005,44 @@ wxThreadError wxThread::Delete(ExitCode *pRc) // Delete() is always safe to call, so consider all possible states - // has the thread started to run? - bool shouldResume = FALSE; + // 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, + shouldCancel = TRUE, + isRunning = FALSE; + // check if the thread already started to run { wxCriticalSectionLocker lock(m_critsect); if ( m_internal->GetState() == STATE_NEW ) { - // WinThreadStart() will see it and terminate immediately + // 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_internal->SetState(STATE_EXITED); - shouldResume = TRUE; + Resume(); // it knows about STATE_EXITED special case + + shouldCancel = FALSE; + isRunning = TRUE; + + // shouldResume is correctly set to FALSE here + } + else + { + shouldResume = IsPaused(); } } - // is the thread paused? - if ( shouldResume || IsPaused() ) + // resume the thread if it is paused + if ( shouldResume ) Resume(); HANDLE hThread = m_internal->GetHandle(); // does is still run? - if ( IsRunning() ) + if ( isRunning || IsRunning() ) { if ( IsMain() ) { @@ -775,6 +1055,7 @@ wxThreadError wxThread::Delete(ExitCode *pRc) } // ask the thread to terminate + if ( shouldCancel ) { wxCriticalSectionLocker lock(m_critsect); @@ -856,25 +1137,28 @@ wxThreadError wxThread::Delete(ExitCode *pRc) } } - if ( !::GetExitCodeThread(hThread, (LPDWORD)&rc) ) + // 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 { - wxLogLastError("GetExitCodeThread"); + if ( !::GetExitCodeThread(hThread, (LPDWORD)&rc) ) + { + wxLogLastError(wxT("GetExitCodeThread")); - rc = (ExitCode)-1; - } + rc = (ExitCode)-1; + } + } while ( (DWORD)rc == STILL_ACTIVE ); if ( IsDetached() ) { // if the thread exits normally, this is done in WinThreadStart, but in // this case it would have been too early because - // MsgWaitForMultipleObject() would fail if the therad handle was + // MsgWaitForMultipleObject() would fail if the thread handle was // closed while we were waiting on it, so we must do it here delete this; } - wxASSERT_MSG( (DWORD)rc != STILL_ACTIVE, - wxT("thread must be already terminated.") ); - if ( pRc ) *pRc = rc; @@ -912,7 +1196,7 @@ void wxThread::Exit(ExitCode status) delete this; } -#if defined(__VISUALC__) || (defined(__BORLANDC__) && (__BORLANDC__ >= 0x500)) +#ifdef wxUSE_BEGIN_THREAD _endthreadex((unsigned)status); #else // !VC++ ::ExitThread((DWORD)status); @@ -999,9 +1283,7 @@ bool wxThreadModule::OnInit() // in normal circumstances it will only happen if all other // TLS_MINIMUM_AVAILABLE (>= 64) indices are already taken - in other // words, this should never happen - wxLogSysError(_("Thread module initialization failed: " - "impossible to allocate index in thread " - "local storage")); + wxLogSysError(_("Thread module initialization failed: impossible to allocate index in thread local storage")); return FALSE; } @@ -1013,8 +1295,7 @@ bool wxThreadModule::OnInit() ::TlsFree(gs_tlsThisThread); gs_tlsThisThread = 0xFFFFFFFF; - wxLogSysError(_("Thread module initialization failed: " - "can not store value in thread local storage")); + wxLogSysError(_("Thread module initialization failed: can not store value in thread local storage")); return FALSE; } @@ -1034,7 +1315,7 @@ void wxThreadModule::OnExit() { if ( !::TlsFree(gs_tlsThisThread) ) { - wxLogLastError("TlsFree failed."); + wxLogLastError(wxT("TlsFree failed.")); } if ( gs_critsectGui ) @@ -1085,7 +1366,7 @@ void WXDLLEXPORT wxMutexGuiLeave() } else { - // decrement the number of waiters now + // decrement the number of threads waiting for GUI access now wxASSERT_MSG( gs_nWaitingForGui > 0, wxT("calling wxMutexGuiLeave() without entering it first?") ); @@ -1139,7 +1420,7 @@ void WXDLLEXPORT wxWakeUpMainThread() if ( !::PostThreadMessage(gs_idMainThread, WM_NULL, 0, 0) ) { // should never happen - wxLogLastError("PostThreadMessage(WM_NULL)"); + wxLogLastError(wxT("PostThreadMessage(WM_NULL)")); } } @@ -1149,3 +1430,5 @@ bool WXDLLEXPORT wxIsWaitingForThread() } #endif // wxUSE_THREADS + +// vi:sts=4:sw=4:et