(svn r7205) -Fix [FS#350, SF#1560913]: Window allocation and deletion messed with the actual window

 structs inside their array, and possibly invalidating pointers higher up.
 Meaning that any function called within an wndproc could cause unknown/invalid pointers
 once control was returned to this function. Solved by the introduction of an extra
 abstraction layer, an array of z-window positions that is only concerned with the
 pointers.

1 files changed, 14 insertions, 11 deletions

diff --git a/viewport.c b/viewport.c
index d413dec2a..e9ce5cdc7 100644
--- a/viewport.c
+++ b/viewport.c
@@ -183,35 +183,38 @@ void AssignWindowViewport(Window *w, int x, int y,
 
 static Point _vp_move_offs;
 
-static void DoSetViewportPosition(const Window *w, int left, int top, int width, int height)
+static void DoSetViewportPosition(const Window* const *wz, int left, int top, int width, int height)
 {
-	for (; w < _last_window; w++) {
+
+	for (; wz != _last_z_window; wz++) {
+		const Window *w = *wz;
+
 		if (left + width > w->left &&
 				w->left + w->width > left &&
 				top + height > w->top &&
 				w->top + w->height > top) {
 
 			if (left < w->left) {
-				DoSetViewportPosition(w, left, top, w->left - left, height);
-				DoSetViewportPosition(w, left + (w->left - left), top, width - (w->left - left), height);
+				DoSetViewportPosition(wz, left, top, w->left - left, height);
+				DoSetViewportPosition(wz, left + (w->left - left), top, width - (w->left - left), height);
 				return;
 			}
 
 			if (left + width > w->left + w->width) {
-				DoSetViewportPosition(w, left, top, (w->left + w->width - left), height);
-				DoSetViewportPosition(w, left + (w->left + w->width - left), top, width - (w->left + w->width - left) , height);
+				DoSetViewportPosition(wz, left, top, (w->left + w->width - left), height);
+				DoSetViewportPosition(wz, left + (w->left + w->width - left), top, width - (w->left + w->width - left) , height);
 				return;
 			}
 
 			if (top < w->top) {
-				DoSetViewportPosition(w, left, top, width, (w->top - top));
-				DoSetViewportPosition(w, left, top + (w->top - top), width, height - (w->top - top));
+				DoSetViewportPosition(wz, left, top, width, (w->top - top));
+				DoSetViewportPosition(wz, left, top + (w->top - top), width, height - (w->top - top));
 				return;
 			}
 
 			if (top + height > w->top + w->height) {
-				DoSetViewportPosition(w, left, top, width, (w->top + w->height - top));
-				DoSetViewportPosition(w, left, top + (w->top + w->height - top), width , height - (w->top + w->height - top));
+				DoSetViewportPosition(wz, left, top, width, (w->top + w->height - top));
+				DoSetViewportPosition(wz, left, top + (w->top + w->height - top), width , height - (w->top + w->height - top));
 				return;
 			}
 
@@ -294,7 +297,7 @@ static void SetViewportPosition(Window *w, int x, int y)
 		i = top + height - _screen.height;
 		if (i >= 0) height -= i;
 
-		if (height > 0) DoSetViewportPosition(w + 1, left, top, width, height);
+		if (height > 0) DoSetViewportPosition(FindWindowZPosition(w) + 1, left, top, width, height);
 	}
 }