Do not call the message loop on Windows recursively to avoid crashes.

git-svn-id: https://svn.r-project.org/R/trunk@88372 00db46b3-68df-0310-9c12-caf00c1e9a41

Author: kalibera

src/gnuwin32/system.c

@@ -120,9 +120,30 @@ void unset_R_Tcldo(DO_FUNC ptr)
     return;
 }
 
+static int pedepth = 0;
+
+static void depth_cleanup(void *data)
+{
+    pedepth = *(int *)data;
+}
+
 void R_ProcessEvents(void)
 {
-    while (peekevent()) doevent();
+    int old_depth = pedepth;
+    RCNTXT cntxt;
+
+    /* do not enter the graphapp message loop recursively */
+    if (!pedepth && peekevent()) {
+	pedepth++;
+	cntxt.cend = &depth_cleanup;
+	cntxt.cenddata = &old_depth;
+	begincontext(&cntxt, CTXT_CCODE, R_NilValue, R_BaseEnv, R_BaseEnv,
+	             R_NilValue, R_NilValue);
+	while (peekevent()) doevent();
+	endcontext(&cntxt);
+	depth_cleanup(&old_depth);
+    }
+	
     if (cpuLimit > 0.0 || elapsedLimit > 0.0) {
 #ifdef HAVE_CHECK_TIME_LIMITS
 	/* switch to using R_CheckTimeLimits after testing on Windows */