From 495833b7965330cc1db5fdce0a3c86f7ec15e836 Mon Sep 17 00:00:00 2001
From: Simon Hausmann <simon.hausmann@qt.io>
Date: Mon, 11 Dec 2017 15:50:21 +0100
Subject: [PATCH] [ChangeLog][QPA][eglfs] Fix crash when using cursors and
 multiple GL contexts

The hash from QOpenGLContext* to cursor texture/shader data can
accumulate dangling pointers if the program uses multiple contexts on
the same screen. This is fixed by moving the cursor data into the
platform context. The code for deleting the texture and shader program
is omitted as it is tied to the life time of the context and the GL
context deletes its resources automatically upon destruction.

Task-number: QTBUG-65119
Change-Id: Ic3b8e5669d14949af811bdf047e7d47000216180
Reviewed-by: Laszlo Agocs <laszlo.agocs@qt.io>
---
 .../platforms/eglfs/api/qeglfscontext_p.h     |  3 +++
 .../platforms/eglfs/api/qeglfscursor.cpp      | 15 ++++---------
 .../platforms/eglfs/api/qeglfscursor_p.h      | 22 +++++++++----------
 3 files changed, 17 insertions(+), 23 deletions(-)

diff --git a/src/plugins/platforms/eglfs/api/qeglfscontext_p.h b/src/plugins/platforms/eglfs/api/qeglfscontext_p.h
index 96f7f01381..af8725b6b3 100644
--- a/src/plugins/platforms/eglfs/api/qeglfscontext_p.h
+++ b/src/plugins/platforms/eglfs/api/qeglfscontext_p.h
@@ -52,6 +52,7 @@
 //
 
 #include "qeglfsglobal_p.h"
+#include "qeglfscursor_p.h"
 #include <QtEglSupport/private/qeglplatformcontext_p.h>
 #include <QtCore/QVariant>
 
@@ -68,6 +69,8 @@ public:
     void runGLChecks() override;
     void swapBuffers(QPlatformSurface *surface) override;
 
+    QEglFSCursorData cursorData;
+
 private:
     EGLNativeWindowType m_tempWindow;
 };
diff --git a/src/plugins/platforms/eglfs/api/qeglfscursor.cpp b/src/plugins/platforms/eglfs/api/qeglfscursor.cpp
index f46206cab5..22319fcc66 100644
--- a/src/plugins/platforms/eglfs/api/qeglfscursor.cpp
+++ b/src/plugins/platforms/eglfs/api/qeglfscursor.cpp
@@ -40,10 +40,10 @@
 #include "qeglfscursor_p.h"
 #include "qeglfsintegration_p.h"
 #include "qeglfsscreen_p.h"
+#include "qeglfscontext_p.h"
 
 #include <qpa/qwindowsysteminterface.h>
 #include <QtGui/QOpenGLContext>
-#include <QtGui/QOpenGLShaderProgram>
 #include <QtCore/QFile>
 #include <QtCore/QJsonDocument>
 #include <QtCore/QJsonArray>
@@ -115,13 +115,6 @@ void QEglFSCursorDeviceListener::onDeviceListChanged(QInputDeviceManager::Device
 
 void QEglFSCursor::resetResources()
 {
-    if (QOpenGLContext *ctx = QOpenGLContext::currentContext()) {
-        GraphicsContextData &gfx(m_gfx[ctx]);
-        delete gfx.program;
-        glDeleteTextures(1, &gfx.customCursorTexture);
-        glDeleteTextures(1, &gfx.atlasTexture);
-        gfx = GraphicsContextData();
-    }
     m_cursor.customCursorPending = !m_cursor.customCursorImage.isNull();
 }
 
@@ -144,8 +137,8 @@ void QEglFSCursor::createShaderPrograms()
         "   gl_FragColor = texture2D(texture, textureCoord).bgra;\n"
         "}\n";
 
-    GraphicsContextData &gfx(m_gfx[QOpenGLContext::currentContext()]);
-    gfx.program = new QOpenGLShaderProgram;
+    QEglFSCursorData &gfx = static_cast<QEglFSContext*>(QOpenGLContext::currentContext()->handle())->cursorData;
+    gfx.program.reset(new QOpenGLShaderProgram);
     gfx.program->addCacheableShaderFromSourceCode(QOpenGLShader::Vertex, textureVertexProgram);
     gfx.program->addCacheableShaderFromSourceCode(QOpenGLShader::Fragment, textureFragmentProgram);
     gfx.program->bindAttributeLocation("vertexCoordEntry", 0);
@@ -475,7 +468,7 @@ void QEglFSCursor::draw(const QRectF &r)
 {
     StateSaver stateSaver;
 
-    GraphicsContextData &gfx(m_gfx[QOpenGLContext::currentContext()]);
+    QEglFSCursorData &gfx = static_cast<QEglFSContext*>(QOpenGLContext::currentContext()->handle())->cursorData;
     if (!gfx.program) {
         // one time initialization
         initializeOpenGLFunctions();
diff --git a/src/plugins/platforms/eglfs/api/qeglfscursor_p.h b/src/plugins/platforms/eglfs/api/qeglfscursor_p.h
index aaeb83cb99..89c2e89f58 100644
--- a/src/plugins/platforms/eglfs/api/qeglfscursor_p.h
+++ b/src/plugins/platforms/eglfs/api/qeglfscursor_p.h
@@ -56,6 +56,7 @@
 #include <qpa/qplatformscreen.h>
 #include <QtGui/QMatrix4x4>
 #include <QtGui/QOpenGLFunctions>
+#include <QtGui/QOpenGLShaderProgram>
 #include <QtGui/private/qinputdevicemanager_p.h>
 
 QT_BEGIN_NAMESPACE
@@ -81,6 +82,15 @@ private:
 
 #if QT_CONFIG(opengl)
 
+struct QEglFSCursorData {
+    QScopedPointer<QOpenGLShaderProgram> program;
+    int textureEntry = 0;
+    int matEntry = 0;
+    uint customCursorTexture = 0;
+    uint atlasTexture = 0;
+    qint64 customCursorKey = 0;
+};
+
 class Q_EGLFS_EXPORT QEglFSCursor : public QPlatformCursor
                                   , protected QOpenGLFunctions
 {
@@ -143,18 +153,6 @@ private:
     QEglFSCursorDeviceListener *m_deviceListener;
     bool m_updateRequested;
     QMatrix4x4 m_rotationMatrix;
-
-    struct GraphicsContextData {
-        GraphicsContextData() : program(nullptr), textureEntry(0), matEntry(0),
-            customCursorTexture(0), atlasTexture(0), customCursorKey(0) { }
-        QOpenGLShaderProgram *program;
-        int textureEntry;
-        int matEntry;
-        uint customCursorTexture;
-        uint atlasTexture;
-        qint64 customCursorKey;
-    };
-    QHash<QOpenGLContext *, GraphicsContextData> m_gfx;
 };
 #endif // QT_CONFIG(opengl)