eglfs: rework hooks design

There are two problems with the current design:
1. if (hooks) hooks->foo() doesn't work in debug mode when no platform hook
   is defined. The problem doesn't arise in release mode because the compiler
   optimizes away the if (hooks) into a no-op since hooks is NULL when no
   platform hook is defined.
2. Adding a new hook requires changing every platform's hook implementation.

New approach:
1. Define QEglFSHooks as a class with virtual functions. A stub file provides
   the default implementation.
2. Platform hooks derive from above class and reimplement whatever is needed.

The filenames and variables have been changed to be more in line with the
Qt style.

Change-Id: I2eaaa5ad7c8b48a06361c4747d4f210c428c983f
Reviewed-by: Samuel Rødal <samuel.rodal@nokia.com>

6 files changed, 128 insertions, 28 deletions

diff --git a/src/plugins/platforms/eglfs/eglfs.pro b/src/plugins/platforms/eglfs/eglfs.pro
index 9a36cacd05..421bbd5561 100644
--- a/src/plugins/platforms/eglfs/eglfs.pro
+++ b/src/plugins/platforms/eglfs/eglfs.pro
@@ -13,20 +13,21 @@ DESTDIR = $$QT.gui.plugins/platforms
 DEFINES += MESA_EGL_NO_X11_HEADERS
 
 #To test the hooks on x11 (xlib), comment the above define too
-#EGLFS_PLATFORM_HOOKS_SOURCES += qeglfs_hooks_x11.cpp
+#EGLFS_PLATFORM_HOOKS_SOURCES += qeglfshooks_x11.cpp
 #LIBS += -lX11
 
 SOURCES =   main.cpp \
             qeglfsintegration.cpp \
             qeglfswindow.cpp \
             qeglfsbackingstore.cpp \
-            qeglfsscreen.cpp
+            qeglfsscreen.cpp \
+            qeglfshooks_stub.cpp
 
 HEADERS =   qeglfsintegration.h \
             qeglfswindow.h \
             qeglfsbackingstore.h \
             qeglfsscreen.h \
-            qeglfs_hooks.h
+            qeglfshooks.h
 
 QMAKE_LFLAGS += $$QMAKE_LFLAGS_NOUNDEF
 
diff --git a/src/plugins/platforms/eglfs/qeglfs_hooks.h b/src/plugins/platforms/eglfs/qeglfshooks.h
index 628ef1f33b..a56c80261b 100644
--- a/src/plugins/platforms/eglfs/qeglfs_hooks.h
+++ b/src/plugins/platforms/eglfs/qeglfshooks.h
@@ -39,31 +39,34 @@
 **
 ****************************************************************************/
 
-#ifndef QEGLFS_HOOKS_H
-#define QEGLFS_HOOKS_H
+#ifndef QEGLFSHOOKS_H
+#define QEGLFSHOOKS_H
 
 #include "qplatformintegration_qpa.h"
 #include <EGL/egl.h>
 
 QT_BEGIN_NAMESPACE
 
-struct QEglFSHooks {
-    void platformInit();
-    void platformDestroy();
-    EGLNativeDisplayType platformDisplay() const;
-    QSize screenSize() const;
-    EGLNativeWindowType createNativeWindow(const QSize &size);
-    void destroyNativeWindow(EGLNativeWindowType window);
-    bool hasCapability(QPlatformIntegration::Capability cap) const;
+class QEglFSHooks
+{
+public:
+    virtual void platformInit();
+    virtual void platformDestroy();
+    virtual EGLNativeDisplayType platformDisplay() const;
+    virtual QSize screenSize() const;
+    virtual EGLNativeWindowType createNativeWindow(const QSize &size);
+    virtual void destroyNativeWindow(EGLNativeWindowType window);
+    virtual bool hasCapability(QPlatformIntegration::Capability cap) const;
 };
 
 #ifdef EGLFS_PLATFORM_HOOKS
-extern QEglFSHooks platform_hooks;
-static QEglFSHooks *hooks = &platform_hooks;
+extern QEglFSHooks *platformHooks;
+static QEglFSHooks *hooks = platformHooks;
 #else
-static QEglFSHooks *hooks = 0;
+extern QEglFSHooks stubHooks;
+static QEglFSHooks *hooks = &stubHooks;
 #endif
 
 QT_END_NAMESPACE
 
-#endif
+#endif // QEGLFSHOOKS_H
diff --git a/src/plugins/platforms/eglfs/qeglfshooks_stub.cpp b/src/plugins/platforms/eglfs/qeglfshooks_stub.cpp
new file mode 100644
index 0000000000..7cc3527a0c
--- /dev/null
+++ b/src/plugins/platforms/eglfs/qeglfshooks_stub.cpp
@@ -0,0 +1,81 @@
+/****************************************************************************
+**
+** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/
+**
+** This file is part of the qmake spec of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** GNU Lesser General Public License Usage
+** This file may be used under the terms of the GNU Lesser General Public
+** License version 2.1 as published by the Free Software Foundation and
+** appearing in the file LICENSE.LGPL included in the packaging of this
+** file. Please review the following information to ensure the GNU Lesser
+** General Public License version 2.1 requirements will be met:
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights. These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU General
+** Public License version 3.0 as published by the Free Software Foundation
+** and appearing in the file LICENSE.GPL included in the packaging of this
+** file. Please review the following information to ensure the GNU General
+** Public License version 3.0 requirements will be met:
+** http://www.gnu.org/copyleft/gpl.html.
+**
+** Other Usage
+** Alternatively, this file may be used in accordance with the terms and
+** conditions contained in a signed written agreement between you and Nokia.
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qeglfshooks.h"
+
+void QEglFSHooks::platformInit()
+{
+}
+
+void QEglFSHooks::platformDestroy()
+{
+}
+
+EGLNativeDisplayType QEglFSHooks::platformDisplay() const
+{
+    return EGL_DEFAULT_DISPLAY;
+}
+
+QSize QEglFSHooks::screenSize() const
+{
+    return QSize();
+}
+
+EGLNativeWindowType QEglFSHooks::createNativeWindow(const QSize &size)
+{
+    Q_UNUSED(size);
+    return 0;
+}
+
+void QEglFSHooks::destroyNativeWindow(EGLNativeWindowType window)
+{
+    Q_UNUSED(window);
+}
+
+bool QEglFSHooks::hasCapability(QPlatformIntegration::Capability cap) const
+{
+    Q_UNUSED(cap);
+    return false;
+}
+
+#ifndef EGLFS_PLATFORM_HOOKS
+QEglFSHooks stubHooks;
+#endif
diff --git a/src/plugins/platforms/eglfs/qeglfs_hooks_x11.cpp b/src/plugins/platforms/eglfs/qeglfshooks_x11.cpp
index 594614e7a0..cb788c52f2 100644
--- a/src/plugins/platforms/eglfs/qeglfs_hooks_x11.cpp
+++ b/src/plugins/platforms/eglfs/qeglfshooks_x11.cpp
@@ -39,31 +39,42 @@
 **
 ****************************************************************************/
 
-#include "qeglfs_hooks.h"
+#include "qeglfshooks.h"
 
 #include <X11/Xlib.h>
 
-QEglFSHooks platform_hooks;
+class QEglFSX11Hooks : public QEglFSHooks
+{
+public:
+    virtual void platformInit();
+    virtual void platformDestroy();
+    virtual EGLNativeDisplayType platformDisplay() const;
+    virtual QSize screenSize() const;
+    virtual EGLNativeWindowType createNativeWindow(const QSize &size);
+    virtual void destroyNativeWindow(EGLNativeWindowType window);
+    virtual bool hasCapability(QPlatformIntegration::Capability cap) const;
+};
+
 static Display *display = 0;
 
-void QEglFSHooks::platformInit()
+void QEglFSX11Hooks::platformInit()
 {
     display = XOpenDisplay(NULL);
     if (!display)
         qFatal("Could not open display");
 }
 
-void QEglFSHooks::platformDestroy()
+void QEglFSX11Hooks::platformDestroy()
 {
     XCloseDisplay(display);
 }
 
-EGLNativeDisplayType QEglFSHooks::platformDisplay() const
+EGLNativeDisplayType QEglFSX11Hooks::platformDisplay() const
 {
     return display;
 }
 
-QSize QEglFSHooks::screenSize() const
+QSize QEglFSX11Hooks::screenSize() const
 {
     QList<QByteArray> env = qgetenv("EGLFS_X11_SIZE").split('x');
     if (env.length() != 2)
@@ -71,7 +82,7 @@ QSize QEglFSHooks::screenSize() const
     return QSize(env.at(0).toInt(), env.at(1).toInt());
 }
 
-EGLNativeWindowType QEglFSHooks::createNativeWindow(const QSize &size)
+EGLNativeWindowType QEglFSX11Hooks::createNativeWindow(const QSize &size)
 {
     Window root = DefaultRootWindow(display);
     XSetWindowAttributes swa;
@@ -83,13 +94,17 @@ EGLNativeWindowType QEglFSHooks::createNativeWindow(const QSize &size)
     return win;
 }
 
-void QEglFSHooks::destroyNativeWindow(EGLNativeWindowType window)
+void QEglFSX11Hooks::destroyNativeWindow(EGLNativeWindowType window)
 {
     XDestroyWindow(display, window);
 }
 
-bool QEglFSHooks::hasCapability(QPlatformIntegration::Capability cap) const
+bool QEglFSX11Hooks::hasCapability(QPlatformIntegration::Capability cap) const
 {
+    Q_UNUSED(cap);
     return false;
 }
 
+static QEglFSX11Hooks eglFSX11Hooks;
+QEglFSHooks *platformHooks = &eglFSX11Hooks;
+
diff --git a/src/plugins/platforms/eglfs/qeglfsintegration.cpp b/src/plugins/platforms/eglfs/qeglfsintegration.cpp
index b1f5a69570..9b7d9246f9 100644
--- a/src/plugins/platforms/eglfs/qeglfsintegration.cpp
+++ b/src/plugins/platforms/eglfs/qeglfsintegration.cpp
@@ -43,7 +43,7 @@
 
 #include "qeglfswindow.h"
 #include "qeglfsbackingstore.h"
-#include "qeglfs_hooks.h"
+#include "qeglfshooks.h"
 
 #include <QtPlatformSupport/private/qgenericunixfontdatabase_p.h>
 #include <QtPlatformSupport/private/qgenericunixeventdispatcher_p.h>
diff --git a/src/plugins/platforms/eglfs/qeglfsscreen.cpp b/src/plugins/platforms/eglfs/qeglfsscreen.cpp
index 3c2f4c580d..ea939a9821 100644
--- a/src/plugins/platforms/eglfs/qeglfsscreen.cpp
+++ b/src/plugins/platforms/eglfs/qeglfsscreen.cpp
@@ -41,7 +41,7 @@
 
 #include "qeglfsscreen.h"
 #include "qeglfswindow.h"
-#include "qeglfs_hooks.h"
+#include "qeglfshooks.h"
 
 #include <QtPlatformSupport/private/qeglconvenience_p.h>
 #include <QtPlatformSupport/private/qeglplatformcontext_p.h>