thread.cpp

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    HANDLE hProcess = ::GetCurrentProcess();
    DWORD_PTR dwProcMask, dwSysMask;
    if ( ::GetProcessAffinityMask(hProcess, &dwProcMask, &dwSysMask) == 0 )
    {
        wxLogLastError(_T("GetProcessAffinityMask"));

        return false;
    }

    // how many CPUs have we got?
    if ( dwSysMask == 1 )
    {
        // don't bother with all this complicated stuff - on a single
        // processor system it doesn't make much sense anyhow
        return level == 1;
    }

    // calculate the process mask: it's a bit vector with one bit per
    // processor; we want to schedule the process to run on first level
    // CPUs
    DWORD bit = 1;
    while ( bit )
    {
        if ( dwSysMask & bit )
        {
            // ok, we can set this bit
            dwProcMask |= bit;

            // another process added
            if ( !--level )
            {
                // and that's enough
                break;
            }
        }

        // next bit
        bit <<= 1;
    }

    // could we set all bits?
    if ( level != 0 )
    {
        wxLogDebug(_T("bad level %u in wxThread::SetConcurrency()"), level);

        return false;
    }

    // set it: we can't link to SetProcessAffinityMask() because it doesn't
    // exist in Win9x, use RT binding instead

    typedef BOOL (*SETPROCESSAFFINITYMASK)(HANDLE, DWORD);

    // can use static var because we're always in the main thread here
    static SETPROCESSAFFINITYMASK pfnSetProcessAffinityMask = NULL;

    if ( !pfnSetProcessAffinityMask )
    {
        HMODULE hModKernel = ::LoadLibrary(_T("kernel32"));
        if ( hModKernel )
        {
            pfnSetProcessAffinityMask = (SETPROCESSAFFINITYMASK)
                ::GetProcAddress(hModKernel, "SetProcessAffinityMask");
        }

        // we've discovered a MT version of Win9x!
        wxASSERT_MSG( pfnSetProcessAffinityMask,
                      _T("this system has several CPUs but no SetProcessAffinityMask function?") );
    }

    if ( !pfnSetProcessAffinityMask )
    {
        // msg given above - do it only once
        return false;
    }

    if ( pfnSetProcessAffinityMask(hProcess, dwProcMask) == 0 )
    {
        wxLogLastError(_T("SetProcessAffinityMask"));

        return false;
    }

    return true;
#endif // __WXWINCE__/!__WXWINCE__
}

// ctor and dtor
// -------------

wxThread::wxThread(wxThreadKind kind)
{
    m_internal = new wxThreadInternal(this);

    m_isDetached = kind == wxTHREAD_DETACHED;
}

wxThread::~wxThread()
{
    delete m_internal;
}

// create/start thread
// -------------------

wxThreadError wxThread::Create(unsigned int stackSize)
{
    wxCriticalSectionLocker lock(m_critsect);

    if ( !m_internal->Create(this, stackSize) )
        return wxTHREAD_NO_RESOURCE;

    return wxTHREAD_NO_ERROR;
}

wxThreadError wxThread::Run()
{
    wxCriticalSectionLocker lock(m_critsect);

    if ( m_internal->GetState() != STATE_NEW )
    {
        // actually, it may be almost any state at all, not only STATE_RUNNING
        return wxTHREAD_RUNNING;
    }

    // the thread has just been created and is still suspended - let it run
    return Resume();
}

// suspend/resume thread
// ---------------------

wxThreadError wxThread::Pause()
{
    wxCriticalSectionLocker lock(m_critsect);

    return m_internal->Suspend() ? wxTHREAD_NO_ERROR : wxTHREAD_MISC_ERROR;
}

wxThreadError wxThread::Resume()
{
    wxCriticalSectionLocker lock(m_critsect);

    return m_internal->Resume() ? wxTHREAD_NO_ERROR : wxTHREAD_MISC_ERROR;
}

// stopping thread
// ---------------

wxThread::ExitCode wxThread::Wait()
{
    // although under Windows we can wait for any thread, it's an error to
    // wait for a detached one in wxWin API
    wxCHECK_MSG( !IsDetached(), (ExitCode)-1,
                 _T("wxThread::Wait(): can't wait for detached thread") );

    ExitCode rc = (ExitCode)-1;

    (void)m_internal->WaitForTerminate(m_critsect, &rc);

    return rc;
}

wxThreadError wxThread::Delete(ExitCode *pRc)
{
    return m_internal->WaitForTerminate(m_critsect, pRc, this);
}

wxThreadError wxThread::Kill()
{
    if ( !IsRunning() )
        return wxTHREAD_NOT_RUNNING;

    wxThreadError rc = m_internal->Kill();

    if ( IsDetached() )
    {
        delete this;
    }
    else // joinable
    {
        // update the status of the joinable thread
        wxCriticalSectionLocker lock(m_critsect);
        m_internal->SetState(STATE_EXITED);
    }

    return rc;
}

void wxThread::Exit(ExitCode status)
{
    m_internal->Free();

    if ( IsDetached() )
    {
        delete this;
    }
    else // joinable
    {
        // update the status of the joinable thread
        wxCriticalSectionLocker lock(m_critsect);
        m_internal->SetState(STATE_EXITED);
    }

#ifdef wxUSE_BEGIN_THREAD
    _endthreadex((unsigned)status);
#else // !VC++
    ::ExitThread((DWORD)status);
#endif // VC++/!VC++

    wxFAIL_MSG(wxT("Couldn't return from ExitThread()!"));
}

// priority setting
// ----------------

void wxThread::SetPriority(unsigned int prio)
{
    wxCriticalSectionLocker lock(m_critsect);

    m_internal->SetPriority(prio);
}

unsigned int wxThread::GetPriority() const
{
    wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast

    return m_internal->GetPriority();
}

unsigned long wxThread::GetId() const
{
    wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast

    return (unsigned long)m_internal->GetId();
}

bool wxThread::IsRunning() const
{
    wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast

    return m_internal->GetState() == STATE_RUNNING;
}

bool wxThread::IsAlive() const
{
    wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast

    return (m_internal->GetState() == STATE_RUNNING) ||
           (m_internal->GetState() == STATE_PAUSED);
}

bool wxThread::IsPaused() const
{
    wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast

    return m_internal->GetState() == STATE_PAUSED;
}

bool wxThread::TestDestroy()
{
    wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast

    return m_internal->GetState() == STATE_CANCELED;
}

// ----------------------------------------------------------------------------
// Automatic initialization for thread module
// ----------------------------------------------------------------------------

class wxThreadModule : public wxModule
{
public:
    virtual bool OnInit();
    virtual void OnExit();

private:
    DECLARE_DYNAMIC_CLASS(wxThreadModule)
};

IMPLEMENT_DYNAMIC_CLASS(wxThreadModule, wxModule)

bool wxThreadModule::OnInit()
{
    // allocate TLS index for storing the pointer to the current thread
    gs_tlsThisThread = ::TlsAlloc();
    if ( gs_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(gs_tlsThisThread, (LPVOID)0) )
    {
        ::TlsFree(gs_tlsThisThread);
        gs_tlsThisThread = 0xFFFFFFFF;

        wxLogSysError(_("Thread module initialization failed: can not store value in thread local storage"));

        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;
}

void wxThreadModule::OnExit()
{
    if ( !::TlsFree(gs_tlsThisThread) )
    {
        wxLogLastError(wxT("TlsFree failed."));
    }

    delete gs_critsectThreadDelete;
    gs_critsectThreadDelete = NULL;

    if ( gs_critsectGui )
    {
        gs_critsectGui->Leave();
        delete gs_critsectGui;
        gs_critsectGui = NULL;
    }

    delete gs_critsectWaitingForGui;
    gs_critsectWaitingForGui = NULL;
}

// ----------------------------------------------------------------------------
// under Windows, these functions are implemented using a critical section and
// not a mutex, so the names are a bit confusing
// ----------------------------------------------------------------------------

void WXDLLIMPEXP_BASE wxMutexGuiEnter()
{
    // this would dead lock everything...
    wxASSERT_MSG( !wxThread::IsMain(),
                  wxT("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(*gs_critsectWaitingForGui);

        gs_nWaitingForGui++;
    }

    wxWakeUpMainThread();

    // now we may block here because the main thread will soon let us in
    // (during the next iteration of OnIdle())
    gs_critsectGui->Enter();
}

void WXDLLIMPEXP_BASE wxMutexGuiLeave()
{
    wxCriticalSectionLocker enter(*gs_critsectWaitingForGui);

    if ( wxThread::IsMain() )
    {
        gs_bGuiOwnedByMainThread = false;
    }
    else
    {
        // decrement the number of threads waiting for GUI access now
        wxASSERT_MSG( gs_nWaitingForGui > 0,
                      wxT("calling wxMutexGuiLeave() without entering it first?") );

        gs_nWaitingForGui--;

        wxWakeUpMainThread();
    }

    gs_critsectGui->Leave();
}

void WXDLLIMPEXP_BASE wxMutexGuiLeaveOrEnter()
{
    wxASSERT_MSG( wxThread::IsMain(),
                  wxT("only main thread may call wxMutexGuiLeaveOrEnter()!") );

    wxCriticalSectionLocker enter(*gs_critsectWaitingForGui);

    if ( gs_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() )
        {
            gs_critsectGui->Enter();

            gs_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 WXDLLIMPEXP_BASE wxGuiOwnedByMainThread()
{
    return gs_bGuiOwnedByMainThread;
}

// wake up the main thread if it's in ::GetMessage()
void WXDLLIMPEXP_BASE wxWakeUpMainThread()
{
    // sending any message would do - hopefully WM_NULL is harmless enough
    if ( !::PostThreadMessage(gs_idMainThread, WM_NULL, 0, 0) )
    {
        // should never happen
        wxLogLastError(wxT("PostThreadMessage(WM_NULL)"));
    }
}

bool WXDLLIMPEXP_BASE wxIsWaitingForThread()
{
    return gs_waitingForThread;
}

// ----------------------------------------------------------------------------
// include common implementation code
// ----------------------------------------------------------------------------

#include "wx/thrimpl.cpp"

#endif // wxUSE_THREADS