add Jtk_CheckEvent()

src/gui/jtk/Jtk_event.cc

@@ -335,17 +335,15 @@ static bool ProcessXEvent(XEvent * x_event, Jtk_Event * event)
     return false;
 }
 
-void Jtk_WaitEvent(Jtk_Event * event)
+bool Jtk_CheckEvent(Jtk_Event * event)
 {
-    for (;;)
-    {
     /* First check for an X event. */
     while (XPending(g_display) > 0)
     {
         XEvent x_event;
         XNextEvent(g_display, &x_event);
         if (ProcessXEvent(&x_event, event))
-                return;
+            return true;
     }
 
     /* Next check if any timer has expired. */
@@ -372,10 +370,20 @@ void Jtk_WaitEvent(Jtk_Event * event)
         }
 #endif
         Jtk_ServiceTimer(timer_id);
-            return;
+        return true;
     }
 
-        /* Finally, wait for something to happen. */
+    return false;
+}
+
+void Jtk_WaitEvent(Jtk_Event * event)
+{
+    for (;;)
+    {
+        if (Jtk_CheckEvent(event))
+            return;
+
+        /* Wait for something to happen. */
         uint64_t time_to_wait = Jtk_TimeToNextTimerExpiration();
         if (time_to_wait > MAX_WAIT_TIME)
         {

src/gui/jtk/Jtk_event.h

@@ -52,6 +52,7 @@ typedef struct
     };
 } Jtk_Event;
 
+bool Jtk_CheckEvent(Jtk_Event * event);
 void Jtk_WaitEvent(Jtk_Event * event);
 #if 0
 void Jtk_BeginKeyRepeat(Jtk_KeyEvent * key_event, uint32_t delay, uint32_t interval);