X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/78322206b87bfa0e129f924d31b62c27ccbfc78b..c6eba8f8b204b0d722db0007e3e0d5e2d2d20085:/src/msw/thread.cpp diff --git a/src/msw/thread.cpp b/src/msw/thread.cpp index 176d1e4cc1..1b26944ae7 100644 --- a/src/msw/thread.cpp +++ b/src/msw/thread.cpp @@ -2,324 +2,863 @@ // Name: thread.cpp // Purpose: wxThread Implementation // Author: Original from Wolfram Gloger/Guilhem Lavaux -// Modified by: +// Modified by: Vadim Zeitlin to make it work :-) // Created: 04/22/98 // RCS-ID: $Id$ -// Copyright: (c) Wolfram Gloger (1996, 1997); Guilhem Lavaux (1998) +// Copyright: (c) Wolfram Gloger (1996, 1997); Guilhem Lavaux (1998), +// Vadim Zeitlin (1999) // Licence: wxWindows licence ///////////////////////////////////////////////////////////////////////////// #ifdef __GNUG__ -#pragma implementation "thread.h" + #pragma implementation "thread.h" #endif -// this is here to regen the precompiled header in the ide compile otherwise the -// compiler crashes in vc5 (nfi why) +// ---------------------------------------------------------------------------- +// headers +// ---------------------------------------------------------------------------- + // For compilers that support precompilation, includes "wx.h". #include "wx/wxprec.h" #if defined(__BORLANDC__) -#pragma hdrstop + #pragma hdrstop #endif #ifndef WX_PRECOMP -#include "wx/wx.h" + #include "wx/wx.h" #endif +#if wxUSE_THREADS + #include #include + #include "wx/module.h" #include "wx/thread.h" -enum thread_state { - STATE_IDLE = 0, - STATE_RUNNING, - STATE_CANCELED, - STATE_EXITED +// the possible states of the thread ("=>" shows all possible transitions from +// this state) +enum wxThreadState +{ + STATE_NEW, // didn't start execution yet (=> RUNNING) + STATE_RUNNING, // thread is running (=> PAUSED, CANCELED) + STATE_PAUSED, // thread is temporarily suspended (=> RUNNING) + STATE_CANCELED, // thread should terminate a.s.a.p. (=> EXITED) + STATE_EXITED // thread is terminating }; -///////////////////////////////////////////////////////////////////////////// -// Static variables -///////////////////////////////////////////////////////////////////////////// +// ---------------------------------------------------------------------------- +// static variables +// ---------------------------------------------------------------------------- -static HANDLE p_mainid; -wxMutex wxMainMutex; // controls access to all GUI functions +// TLS index of the slot where we store the pointer to the current thread +static DWORD s_tlsThisThread = 0xFFFFFFFF; -///////////////////////////////////////////////////////////////////////////// -// Windows implementation -///////////////////////////////////////////////////////////////////////////// +// id of the main thread - the one which can call GUI functions without first +// calling wxMutexGuiEnter() +static DWORD s_idMainThread = 0; + +// if it's FALSE, some secondary thread is holding the GUI lock +static bool s_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 +// any GUI calls +static wxCriticalSection *s_critsectGui = NULL; -class wxMutexInternal { +// critical section which protects s_nWaitingForGui variable +static wxCriticalSection *s_critsectWaitingForGui = NULL; + +// number of threads waiting for GUI in wxMutexGuiEnter() +static size_t s_nWaitingForGui = 0; + +// are we waiting for a thread termination? +static bool s_waitingForThread = FALSE; + +// ============================================================================ +// Windows implementation of thread classes +// ============================================================================ + +// ---------------------------------------------------------------------------- +// wxMutex implementation +// ---------------------------------------------------------------------------- +class wxMutexInternal +{ public: - HANDLE p_mutex; + HANDLE p_mutex; }; wxMutex::wxMutex() { - p_internal = new wxMutexInternal; - p_internal->p_mutex = CreateMutex(NULL, FALSE, NULL); - m_locked = 0; + p_internal = new wxMutexInternal; + p_internal->p_mutex = CreateMutex(NULL, FALSE, NULL); + if ( !p_internal->p_mutex ) + { + wxLogSysError(_("Can not create mutex.")); + } + + m_locked = 0; } wxMutex::~wxMutex() { - if (m_locked > 0) - wxDebugMsg("wxMutex warning: freeing a locked mutex (%d locks)\n", m_locked); - CloseHandle(p_internal->p_mutex); + if (m_locked > 0) + wxLogDebug("Warning: freeing a locked mutex (%d locks).", m_locked); + CloseHandle(p_internal->p_mutex); } wxMutexError wxMutex::Lock() { - DWORD ret; + DWORD ret; - ret = WaitForSingleObject(p_internal->p_mutex, INFINITE); - if (ret == WAIT_ABANDONED) - return MUTEX_BUSY; + ret = WaitForSingleObject(p_internal->p_mutex, INFINITE); + switch ( ret ) + { + case WAIT_ABANDONED: + return wxMUTEX_BUSY; - m_locked++; - return MUTEX_NO_ERROR; + case WAIT_OBJECT_0: + // ok + break; + + case WAIT_FAILED: + wxLogSysError(_("Couldn't acquire a mutex lock")); + return wxMUTEX_MISC_ERROR; + + case WAIT_TIMEOUT: + default: + wxFAIL_MSG("impossible return value in wxMutex::Lock"); + } + + m_locked++; + return wxMUTEX_NO_ERROR; } wxMutexError wxMutex::TryLock() { - DWORD ret; + DWORD ret; - ret = WaitForSingleObject(p_internal->p_mutex, 0); - if (ret == WAIT_TIMEOUT || ret == WAIT_ABANDONED) - return MUTEX_BUSY; + ret = WaitForSingleObject(p_internal->p_mutex, 0); + if (ret == WAIT_TIMEOUT || ret == WAIT_ABANDONED) + return wxMUTEX_BUSY; - m_locked++; - return MUTEX_NO_ERROR; + m_locked++; + return wxMUTEX_NO_ERROR; } wxMutexError wxMutex::Unlock() { - BOOL ret; + if (m_locked > 0) + m_locked--; - if (m_locked > 0) - m_locked--; + BOOL ret = ReleaseMutex(p_internal->p_mutex); + if ( ret == 0 ) + { + wxLogSysError(_("Couldn't release a mutex")); + return wxMUTEX_MISC_ERROR; + } - // Why does this have 3 args? The redundant ones removed by JACS -// ret = ReleaseMutex(p_internal->p_mutex, 1, NULL); - ret = ReleaseMutex(p_internal->p_mutex); - return MUTEX_NO_ERROR; + return wxMUTEX_NO_ERROR; } -class wxConditionInternal { +// ---------------------------------------------------------------------------- +// wxCondition implementation +// ---------------------------------------------------------------------------- + +class wxConditionInternal +{ public: - HANDLE event; - int waiters; + HANDLE event; + int waiters; }; wxCondition::wxCondition() { - p_internal = new wxConditionInternal; - p_internal->event = CreateEvent(NULL, FALSE, FALSE, NULL); - p_internal->waiters = 0; + p_internal = new wxConditionInternal; + p_internal->event = CreateEvent(NULL, FALSE, FALSE, NULL); + if ( !p_internal->event ) + { + wxLogSysError(_("Can not create event object.")); + } + + p_internal->waiters = 0; } wxCondition::~wxCondition() { - CloseHandle(p_internal->event); + CloseHandle(p_internal->event); } void wxCondition::Wait(wxMutex& mutex) { - mutex.Unlock(); - p_internal->waiters++; - WaitForSingleObject(p_internal->event, INFINITE); - p_internal->waiters--; - mutex.Lock(); + mutex.Unlock(); + p_internal->waiters++; + WaitForSingleObject(p_internal->event, INFINITE); + p_internal->waiters--; + mutex.Lock(); } -bool wxCondition::Wait(wxMutex& mutex, unsigned long sec, +bool wxCondition::Wait(wxMutex& mutex, + unsigned long sec, unsigned long nsec) { - DWORD ret; + DWORD ret; - mutex.Unlock(); - p_internal->waiters++; - ret = WaitForSingleObject(p_internal->event, (sec*1000)+(nsec/1000000)); - p_internal->waiters--; - mutex.Lock(); + mutex.Unlock(); + p_internal->waiters++; + ret = WaitForSingleObject(p_internal->event, (sec*1000)+(nsec/1000000)); + p_internal->waiters--; + mutex.Lock(); - return (ret != WAIT_TIMEOUT); + return (ret != WAIT_TIMEOUT); } void wxCondition::Signal() { - SetEvent(p_internal->event); + SetEvent(p_internal->event); } void wxCondition::Broadcast() { - int i; - - for (i=0;iwaiters;i++) - SetEvent(p_internal->event); + int i; + + for (i=0;iwaiters;i++) + { + if ( SetEvent(p_internal->event) == 0 ) + { + wxLogSysError(_("Couldn't change the state of event object.")); + } + } } -class wxThreadInternal { +// ---------------------------------------------------------------------------- +// wxCriticalSection implementation +// ---------------------------------------------------------------------------- + +class wxCriticalSectionInternal +{ public: - static DWORD WinThreadStart(LPVOID arg); + // init the critical section object + wxCriticalSectionInternal() + { ::InitializeCriticalSection(&m_data); } - HANDLE thread_id; - int state; - int prio, defer; - DWORD tid; + // implicit cast to the associated data + operator CRITICAL_SECTION *() { return &m_data; } + + // free the associated ressources + ~wxCriticalSectionInternal() + { ::DeleteCriticalSection(&m_data); } + +private: + CRITICAL_SECTION m_data; }; -DWORD wxThreadInternal::WinThreadStart(LPVOID arg) +wxCriticalSection::wxCriticalSection() +{ + m_critsect = new wxCriticalSectionInternal; +} + +wxCriticalSection::~wxCriticalSection() { - wxThread *ptr = (wxThread *)arg; - DWORD ret; + delete m_critsect; +} - ret = (DWORD)ptr->Entry(); - ptr->p_internal->state = STATE_EXITED; +void wxCriticalSection::Enter() +{ + ::EnterCriticalSection(*m_critsect); +} - return ret; +void wxCriticalSection::Leave() +{ + ::LeaveCriticalSection(*m_critsect); } -wxThreadError wxThread::Create() +// ---------------------------------------------------------------------------- +// wxThread implementation +// ---------------------------------------------------------------------------- + +// wxThreadInternal class +// ---------------------- + +class wxThreadInternal { - int win_prio, prio = p_internal->prio; +public: + wxThreadInternal() + { + m_hThread = 0; + m_state = STATE_NEW; + m_priority = WXTHREAD_DEFAULT_PRIORITY; + } + + // create a new (suspended) thread (for the given thread object) + bool Create(wxThread *thread); + + // suspend/resume/terminate + bool Suspend(); + bool Resume(); + void Cancel() { m_state = STATE_CANCELED; } + + // thread state + void SetState(wxThreadState state) { m_state = state; } + wxThreadState GetState() const { return m_state; } + + // thread priority + void SetPriority(unsigned int priority) { m_priority = priority; } + unsigned int GetPriority() const { return m_priority; } + + // thread handle and id + HANDLE GetHandle() const { return m_hThread; } + DWORD GetId() const { return m_tid; } + + // thread function + static DWORD WinThreadStart(wxThread *thread); + +private: + 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 +}; - p_internal->thread_id = CreateThread(NULL, 0, - (LPTHREAD_START_ROUTINE)wxThreadInternal::WinThreadStart, - (void *)this, CREATE_SUSPENDED, &p_internal->tid); - if (p_internal->thread_id == NULL) { - printf("Error = %d\n", GetLastError()); - return THREAD_NO_RESOURCE; - } +DWORD wxThreadInternal::WinThreadStart(wxThread *thread) +{ + // store the thread object in the TLS + if ( !::TlsSetValue(s_tlsThisThread, thread) ) + { + wxLogSysError(_("Can not start thread: error writing TLS.")); - if (prio <= 20) - win_prio = THREAD_PRIORITY_LOWEST; - else if (prio <= 40) - win_prio = THREAD_PRIORITY_BELOW_NORMAL; - else if (prio <= 60) - win_prio = THREAD_PRIORITY_NORMAL; - else if (prio <= 80) - win_prio = THREAD_PRIORITY_ABOVE_NORMAL; - else if (prio <= 100) - win_prio = THREAD_PRIORITY_HIGHEST; + return (DWORD)-1; + } - SetThreadPriority(p_internal->thread_id, win_prio); + DWORD ret = (DWORD)thread->Entry(); + thread->p_internal->SetState(STATE_EXITED); + thread->OnExit(); - ResumeThread(p_internal->thread_id); - p_internal->state = STATE_RUNNING; - - return THREAD_NO_ERROR; + delete thread; + + return ret; +} + +bool wxThreadInternal::Create(wxThread *thread) +{ + m_hThread = ::CreateThread + ( + NULL, // default security + 0, // default stack size + (LPTHREAD_START_ROUTINE) // thread entry point + wxThreadInternal::WinThreadStart, // + (LPVOID)thread, // parameter + CREATE_SUSPENDED, // flags + &m_tid // [out] thread id + ); + + if ( m_hThread == NULL ) + { + wxLogSysError(_("Can't create thread")); + + return FALSE; + } + + // translate wxWindows priority to the Windows one + int win_priority; + if (m_priority <= 20) + win_priority = THREAD_PRIORITY_LOWEST; + else if (m_priority <= 40) + win_priority = THREAD_PRIORITY_BELOW_NORMAL; + else if (m_priority <= 60) + win_priority = THREAD_PRIORITY_NORMAL; + else if (m_priority <= 80) + win_priority = THREAD_PRIORITY_ABOVE_NORMAL; + else if (m_priority <= 100) + win_priority = THREAD_PRIORITY_HIGHEST; + else + { + wxFAIL_MSG("invalid value of thread priority parameter"); + win_priority = THREAD_PRIORITY_NORMAL; + } + + if ( ::SetThreadPriority(m_hThread, win_priority) == 0 ) + { + wxLogSysError(_("Can't set thread priority")); + } + + return TRUE; } -wxThreadError wxThread::Destroy() +bool wxThreadInternal::Suspend() { - if (p_internal->state != STATE_RUNNING) - return THREAD_NOT_RUNNING; + DWORD nSuspendCount = ::SuspendThread(m_hThread); + if ( nSuspendCount == (DWORD)-1 ) + { + wxLogSysError(_("Can not suspend thread %x"), m_hThread); + + return FALSE; + } - if (p_internal->defer == FALSE) - TerminateThread(p_internal->thread_id, 0); - else - p_internal->state = STATE_CANCELED; + m_state = STATE_PAUSED; - return THREAD_NO_ERROR; + return TRUE; } -void wxThread::Exit(void *status) +bool wxThreadInternal::Resume() +{ + DWORD nSuspendCount = ::ResumeThread(m_hThread); + if ( nSuspendCount == (DWORD)-1 ) + { + wxLogSysError(_("Can not resume thread %x"), m_hThread); + + return FALSE; + } + + m_state = STATE_RUNNING; + + return TRUE; +} + +// static functions +// ---------------- + +wxThread *wxThread::This() +{ + wxThread *thread = (wxThread *)::TlsGetValue(s_tlsThisThread); + + // be careful, 0 may be a valid return value as well + if ( !thread && (::GetLastError() != NO_ERROR) ) + { + wxLogSysError(_("Couldn't get the current thread pointer")); + + // return NULL... + } + + return thread; +} + +bool wxThread::IsMain() +{ + return ::GetCurrentThreadId() == s_idMainThread; +} + +#ifdef Yield + #undef Yield +#endif + +void wxThread::Yield() +{ + // 0 argument to Sleep() is special + ::Sleep(0); +} + +void wxThread::Sleep(unsigned long milliseconds) +{ + ::Sleep(milliseconds); +} + +// create/start thread +// ------------------- + +wxThreadError wxThread::Create() +{ + if ( !p_internal->Create(this) ) + return wxTHREAD_NO_RESOURCE; + + return wxTHREAD_NO_ERROR; +} + +wxThreadError wxThread::Run() { - p_internal->state = STATE_EXITED; - ExitThread((DWORD)status); + wxCriticalSectionLocker lock(m_critsect); + + if ( p_internal->GetState() != STATE_NEW ) + { + // actually, it may be almost any state at all, not only STATE_RUNNING + return wxTHREAD_RUNNING; + } + + return Resume(); } -void wxThread::SetPriority(int prio) +// suspend/resume thread +// --------------------- + +wxThreadError wxThread::Pause() { - p_internal->prio = prio; + wxCriticalSectionLocker lock(m_critsect); + + return p_internal->Suspend() ? wxTHREAD_NO_ERROR : wxTHREAD_MISC_ERROR; } -int wxThread::GetPriority() const +wxThreadError wxThread::Resume() { - return p_internal->prio; + wxCriticalSectionLocker lock(m_critsect); + + return p_internal->Resume() ? wxTHREAD_NO_ERROR : wxTHREAD_MISC_ERROR; } -void wxThread::DeferDestroy(bool on) +// stopping thread +// --------------- + +wxThread::ExitCode wxThread::Delete() { - p_internal->defer = on; + ExitCode rc = 0; + + // Delete() is always safe to call, so consider all possible states + if ( IsPaused() ) + Resume(); + + if ( IsRunning() ) + { + if ( IsMain() ) + { + // set flag for wxIsWaitingForThread() + s_waitingForThread = TRUE; + + wxBeginBusyCursor(); + } + + HANDLE hThread; + { + wxCriticalSectionLocker lock(m_critsect); + + p_internal->Cancel(); + hThread = p_internal->GetHandle(); + } + + // we can't just wait for the thread to terminate because it might be + // calling some GUI functions and so it will never terminate before we + // process the Windows messages that result from these functions + DWORD result; + do + { + result = ::MsgWaitForMultipleObjects + ( + 1, // number of objects to wait for + &hThread, // the objects + FALSE, // don't wait for all objects + INFINITE, // no timeout + QS_ALLEVENTS // return as soon as there are any events + ); + + switch ( result ) + { + case 0xFFFFFFFF: + // error + wxLogSysError(_("Can not wait for thread termination")); + Kill(); + return (ExitCode)-1; + + case WAIT_OBJECT_0: + // thread we're waiting for terminated + break; + + case WAIT_OBJECT_0 + 1: + // new message arrived, process it + if ( !wxTheApp->DoMessage() ) + { + // WM_QUIT received: kill the thread + Kill(); + + return (ExitCode)-1; + } + + if ( IsMain() ) + { + // give the thread we're waiting for chance to exit + // from the GUI call it might have been in + if ( (s_nWaitingForGui > 0) && wxGuiOwnedByMainThread() ) + { + wxMutexGuiLeave(); + } + } + + break; + + default: + wxFAIL_MSG("unexpected result of MsgWaitForMultipleObject"); + } + } while ( result != WAIT_OBJECT_0 ); + + if ( IsMain() ) + { + s_waitingForThread = FALSE; + + wxEndBusyCursor(); + } + + if ( !::GetExitCodeThread(hThread, (LPDWORD)&rc) ) + { + wxLogLastError("GetExitCodeThread"); + + rc = (ExitCode)-1; + } + + wxASSERT_MSG( (LPVOID)rc != (LPVOID)STILL_ACTIVE, + "thread must be already terminated." ); + + ::CloseHandle(hThread); + } + + return rc; } -void wxThread::TestDestroy() +wxThreadError wxThread::Kill() { - if (p_internal->state == STATE_CANCELED) - ExitThread(0); + if ( !IsRunning() ) + return wxTHREAD_NOT_RUNNING; + + if ( !::TerminateThread(p_internal->GetHandle(), (DWORD)-1) ) + { + wxLogSysError(_("Couldn't terminate thread")); + + return wxTHREAD_MISC_ERROR; + } + + delete this; + + return wxTHREAD_NO_ERROR; } -void *wxThread::Join() +void wxThread::Exit(void *status) { - DWORD exit_code; + delete this; - if (p_internal->state == STATE_IDLE) - return NULL; + ::ExitThread((DWORD)status); + + wxFAIL_MSG("Couldn't return from ExitThread()!"); +} - if (wxThread::IsMain()) - wxMainMutex.Unlock(); - WaitForSingleObject(p_internal->thread_id, INFINITE); - if (wxThread::IsMain()) - wxMainMutex.Lock(); +void wxThread::SetPriority(unsigned int prio) +{ + wxCriticalSectionLocker lock(m_critsect); - GetExitCodeThread(p_internal->thread_id, &exit_code); - CloseHandle(p_internal->thread_id); + p_internal->SetPriority(prio); +} - p_internal->state = STATE_IDLE; +unsigned int wxThread::GetPriority() const +{ + wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); - return (void *)exit_code; + return p_internal->GetPriority(); } unsigned long wxThread::GetID() const { - return (unsigned long)p_internal->tid; + wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); + + return (unsigned long)p_internal->GetId(); } -bool wxThread::IsMain() +bool wxThread::IsRunning() const { - return (GetCurrentThread() == p_mainid); + wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); + + return p_internal->GetState() == STATE_RUNNING; } -wxThread::wxThread() +bool wxThread::IsAlive() const { - p_internal = new wxThreadInternal(); + wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); - p_internal->defer = FALSE; - p_internal->prio = WXTHREAD_DEFAULT_PRIORITY; - p_internal->state = STATE_IDLE; + return (p_internal->GetState() == STATE_RUNNING) || + (p_internal->GetState() == STATE_PAUSED); } -wxThread::~wxThread() +bool wxThread::IsPaused() const +{ + wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); + + return (p_internal->GetState() == STATE_PAUSED); +} + +bool wxThread::TestDestroy() +{ + wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); + + return p_internal->GetState() == STATE_CANCELED; +} + +wxThread::wxThread() { - Destroy(); - Join(); - delete p_internal; + p_internal = new wxThreadInternal(); } -// The default callback just joins the thread and throws away the result. -void wxThread::OnExit() +wxThread::~wxThread() { - Join(); + delete p_internal; } -// Automatic initialization -class wxThreadModule : public wxModule { - DECLARE_DYNAMIC_CLASS(wxThreadModule) +// ---------------------------------------------------------------------------- +// Automatic initialization for thread module +// ---------------------------------------------------------------------------- + +class wxThreadModule : public wxModule +{ public: - virtual bool OnInit() { - p_mainid = GetCurrentThread(); - wxMainMutex.Lock(); - return TRUE; - } + virtual bool OnInit(); + virtual void OnExit(); - // Global cleanup - virtual void OnExit() { - wxMainMutex.Unlock(); - } +private: + DECLARE_DYNAMIC_CLASS(wxThreadModule) }; IMPLEMENT_DYNAMIC_CLASS(wxThreadModule, wxModule) +bool wxThreadModule::OnInit() +{ + // allocate TLS index for storing the pointer to the current thread + s_tlsThisThread = ::TlsAlloc(); + if ( s_tlsThisThread == 0xFFFFFFFF ) + { + // 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")); + + return FALSE; + } + + // main thread doesn't have associated wxThread object, so store 0 in the + // TLS instead + if ( !::TlsSetValue(s_tlsThisThread, (LPVOID)0) ) + { + ::TlsFree(s_tlsThisThread); + s_tlsThisThread = 0xFFFFFFFF; + + wxLogSysError(_("Thread module initialization failed: " + "can not store value in thread local storage")); + + return FALSE; + } + + s_critsectWaitingForGui = new wxCriticalSection(); + + s_critsectGui = new wxCriticalSection(); + s_critsectGui->Enter(); + + // no error return for GetCurrentThreadId() + s_idMainThread = ::GetCurrentThreadId(); + + return TRUE; +} + +void wxThreadModule::OnExit() +{ + if ( !::TlsFree(s_tlsThisThread) ) + { + wxLogLastError("TlsFree failed."); + } + + if ( s_critsectGui ) + { + s_critsectGui->Leave(); + delete s_critsectGui; + s_critsectGui = NULL; + } + + wxDELETE(s_critsectWaitingForGui); +} + +// ---------------------------------------------------------------------------- +// under Windows, these functions are implemented usign a critical section and +// not a mutex, so the names are a bit confusing +// ---------------------------------------------------------------------------- + +void WXDLLEXPORT wxMutexGuiEnter() +{ + // this would dead lock everything... + wxASSERT_MSG( !wxThread::IsMain(), + "main thread doesn't want to block in wxMutexGuiEnter()!" ); + + // the order in which we enter the critical sections here is crucial!! + + // set the flag telling to the main thread that we want to do some GUI + { + wxCriticalSectionLocker enter(*s_critsectWaitingForGui); + + s_nWaitingForGui++; + } + + wxWakeUpMainThread(); + + // now we may block here because the main thread will soon let us in + // (during the next iteration of OnIdle()) + s_critsectGui->Enter(); +} + +void WXDLLEXPORT wxMutexGuiLeave() +{ + wxCriticalSectionLocker enter(*s_critsectWaitingForGui); + + if ( wxThread::IsMain() ) + { + s_bGuiOwnedByMainThread = FALSE; + } + else + { + // decrement the number of waiters now + wxASSERT_MSG( s_nWaitingForGui > 0, + "calling wxMutexGuiLeave() without entering it first?" ); + + s_nWaitingForGui--; + + wxWakeUpMainThread(); + } + + s_critsectGui->Leave(); +} + +void WXDLLEXPORT wxMutexGuiLeaveOrEnter() +{ + wxASSERT_MSG( wxThread::IsMain(), + "only main thread may call wxMutexGuiLeaveOrEnter()!" ); + + wxCriticalSectionLocker enter(*s_critsectWaitingForGui); + + if ( s_nWaitingForGui == 0 ) + { + // no threads are waiting for GUI - so we may acquire the lock without + // any danger (but only if we don't already have it) + if ( !wxGuiOwnedByMainThread() ) + { + s_critsectGui->Enter(); + + s_bGuiOwnedByMainThread = TRUE; + } + //else: already have it, nothing to do + } + else + { + // some threads are waiting, release the GUI lock if we have it + if ( wxGuiOwnedByMainThread() ) + { + wxMutexGuiLeave(); + } + //else: some other worker thread is doing GUI + } +} + +bool WXDLLEXPORT wxGuiOwnedByMainThread() +{ + return s_bGuiOwnedByMainThread; +} + +// wake up the main thread if it's in ::GetMessage() +void WXDLLEXPORT wxWakeUpMainThread() +{ + // sending any message would do - hopefully WM_NULL is harmless enough + if ( !::PostThreadMessage(s_idMainThread, WM_NULL, 0, 0) ) + { + // should never happen + wxLogLastError("PostThreadMessage(WM_NULL)"); + } +} + +bool WXDLLEXPORT wxIsWaitingForThread() +{ + return s_waitingForThread; +} + +#endif // wxUSE_THREADS