Make main thread wake up code more efficient and less error-prone in wxMSW.

Use a kernel event object to signal the thread wake up instead of sending
WM_NULL to one of its windows. This is simpler as we don't need to look for
any windows and doesn't suffer from the problem of overflowing the Windows
message queue if we do it too many times as signalling an already signalled
event simply doesn't do anything.

Closes #9053.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@78041 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/msw/evtloopconsole.h

@@ -15,9 +15,20 @@ class WXDLLIMPEXP_BASE wxMSWEventLoopBase : public wxEventLoopManual
 {
 public:
     wxMSWEventLoopBase();
+    virtual ~wxMSWEventLoopBase();
 
     // implement base class pure virtuals
     virtual bool Pending() const;
+    virtual void WakeUp();
+
+#if wxUSE_THREADS
+    // MSW-specific method to wait for the termination of the specified (by its
+    // native handle) thread or any input message arriving (in GUI case).
+    //
+    // Return value is WAIT_OBJECT_0 if the thread terminated, WAIT_OBJECT_0+1
+    // if a message arrived with anything else indicating an error.
+    WXDWORD MSWWaitForThread(WXHANDLE hThread);
+#endif // wxUSE_THREADS
 
 protected:
     // get the next message from queue and return true or return false if we
@@ -25,8 +36,13 @@ protected:
     bool GetNextMessage(WXMSG *msg);
 
     // same as above but with a timeout and return value can be -1 meaning that
-    // time out expired in addition to
+    // time out expired in addition to true/false
     int GetNextMessageTimeout(WXMSG *msg, unsigned long timeout);
+
+private:
+    // An auto-reset Win32 event which is signalled when we need to wake up the
+    // main thread waiting in GetNextMessage[Timeout]().
+    WXHANDLE m_heventWake;
 };
 
 #if wxUSE_CONSOLE_EVENTLOOP
@@ -39,7 +55,6 @@ public:
     // override/implement base class virtuals
     virtual bool Dispatch();
     virtual int DispatchTimeout(unsigned long timeout);
-    virtual void WakeUp();
 
     // Windows-specific function to process a single message
     virtual void ProcessMessage(WXMSG *msg);