From 3ad56045805b50ade252e4353eac158e7eee7b5f Mon Sep 17 00:00:00 2001
From: Vlad Zagorodniy <vladzzag@gmail.com>
Date: Sun, 2 Dec 2018 13:59:45 +0200
Subject: [PATCH] [scenes/opengl] Cleanup cached decoration shadow textures
 when suspending compositing

Summary:
When suspending compositing, SceneOpenGLShadow cannot cleanup cached
decoration shadow textures because the effects handler is already gone.

This sometimes can result in a crash when running kwin_x11 --replace
(we're hitting an assert statement).

To fix that, let's use the scene instead of the effects handler for
making the OpenGL context current.

Test Plan:
No longer hit the assert statement:

    ASSERT: "m_cache.isEmpty()" in file /home/vlad/Workspace/KDE/src/kde/workspace/kwin/plugins/scenes/opengl/scene_opengl.cpp, line 2025
    Application::crashHandler() called with signal 6; recent crashes: 1
    QCoreApplication::applicationFilePath: Please instantiate the QApplication object first
    KCrash: crashing... crashRecursionCounter = 2
    KCrash: Application Name = kwin_x11 path = /home/vlad/Workspace/KDE/usr/bin pid = 5407
    KCrash: Arguments: /home/vlad/Workspace/KDE/usr/bin/kwin_x11 --replace

Reviewers: #kwin, graesslin

Reviewed By: #kwin, graesslin

Subscribers: kwin

Tags: #kwin

Differential Revision: https://phabricator.kde.org/D17306
---
 plugins/scenes/opengl/scene_opengl.cpp | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/plugins/scenes/opengl/scene_opengl.cpp b/plugins/scenes/opengl/scene_opengl.cpp
index 8886fb0d74..49574e79b4 100644
--- a/plugins/scenes/opengl/scene_opengl.cpp
+++ b/plugins/scenes/opengl/scene_opengl.cpp
@@ -2074,8 +2074,9 @@ SceneOpenGLShadow::SceneOpenGLShadow(Toplevel *toplevel)
 
 SceneOpenGLShadow::~SceneOpenGLShadow()
 {
-    if (effects) {
-        effects->makeOpenGLContextCurrent();
+    Scene *scene = Compositor::self()->scene();
+    if (scene) {
+        scene->makeOpenGLContextCurrent();
         DecorationShadowTextureCache::instance().unregister(this);
         m_texture.reset();
     }
@@ -2334,7 +2335,8 @@ bool SceneOpenGLShadow::prepareBackend()
 {
     if (hasDecorationShadow()) {
         // simplifies a lot by going directly to
-        effects->makeOpenGLContextCurrent();
+        Scene *scene = Compositor::self()->scene();
+        scene->makeOpenGLContextCurrent();
         m_texture = DecorationShadowTextureCache::instance().getTexture(this);
 
         return true;
@@ -2403,7 +2405,8 @@ bool SceneOpenGLShadow::prepareBackend()
         }
     }
 
-    effects->makeOpenGLContextCurrent();
+    Scene *scene = Compositor::self()->scene();
+    scene->makeOpenGLContextCurrent();
     m_texture = QSharedPointer<GLTexture>::create(image);
 
     if (m_texture->internalFormat() == GL_R8) {