From 07685da24e5ade698b10e1d13d227b0d0e4f72d0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Gr=C3=A4=C3=9Flin?= <mgraesslin@kde.org>
Date: Fri, 13 Jan 2012 09:01:36 +0100
Subject: [PATCH] Check whether the ShaderManager is valid in Explosion effect

The effect did not check whether the ShaderManager is valid causing
a null pointer access when trying to use the shader.

Additionally this change moves the Shader init into the close window
slot as close window referrenced windows without checking whether the
effect would work. If the effect would not work each closed window
would be referrenced without any chance to being unreffed again as this
code is in a block checking whether the effect is valid.

BUG: 291390
FIXED-IN: 4.8.0
---
 effects/explosion/explosion.cpp | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/effects/explosion/explosion.cpp b/effects/explosion/explosion.cpp
index bdff254f54..dc9cd1441e 100644
--- a/effects/explosion/explosion.cpp
+++ b/effects/explosion/explosion.cpp
@@ -67,6 +67,9 @@ bool ExplosionEffect::supported()
 bool ExplosionEffect::loadData()
 {
     mInited = true;
+    if (!ShaderManager::instance()->isValid()) {
+        return false;
+    }
     QString shadername("explosion");
     const QString fragmentshader =  KGlobal::dirs()->findResource("data", "kwin/explosion.frag");
     QString starttexture =  KGlobal::dirs()->findResource("data", "kwin/explosion-start.png");
@@ -113,8 +116,6 @@ void ExplosionEffect::prePaintScreen(ScreenPrePaintData& data, int time)
 void ExplosionEffect::prePaintWindow(EffectWindow* w, WindowPrePaintData& data, int time)
 {
     if (mWindows.contains(w)) {
-        if (mValid && !mInited)
-            mValid = loadData();
         if (mValid) {
             mWindows[ w  ] += time / animationTime(700.0);   // complete change in 700ms
             if (mWindows[ w  ] < 1) {
@@ -190,6 +191,12 @@ void ExplosionEffect::slotWindowClosed(EffectWindow* c)
     if (e && e != this)
         return;
     if (c->isOnCurrentDesktop() && !c->isMinimized()) {
+        if (mValid && !mInited)
+            mValid = loadData();
+        if (!mValid) {
+            // don't add to list as we cannot animate this window;
+            return;
+        }
         mWindows[ c ] = 0; // count up to 1
         c->addRepaintFull();
         c->refWindow();