Pluginize the eglfs hooks

Following the principle of device integrations in QtWayland and soon
xcb, a plugin interface is being introduced to gradually replace the
statically compiled-in hooks.

The interface is same as before for the time being, for compatibility
with the existing device-specific hooks.

QEglFSHooks is now just a dummy subclass for QEGLDeviceIntegration to
support the legacy, compiled-in, device-specific hooks. When -device
is not used with configure and so there is no hook active, the new
plugin-based approach kicks in.

The environment variable QT_QPA_EGLFS_INTEGRATION can be set to
indicate the preferred integration name (e.g. eglfs_x11, eglfs_kms).

It can also be set to "none", indicating that no plugins should be
considered and the default, non-specialized integration is to be used.
(this is for devices, like Beagleboard|bone, that do not need any special
code to set up EGL)

Device makespecs can set EGLFS_DEVICE_INTEGRATION. The value is then used
as the default, preferred plugin name when QT_QPA_EGLFS_INTEGRATION is not
set. In the future device makespecs are expected to set a plugin name instead
of relying on the traditional EGLFS_PLATFORM_HOOKS_*.

When neither the QT_QPA_EGLFS_INTEGRATION nor EGLFS_DEVICE_INTEGRATION are
set, all plugins will be tried in an unspecified order. The first one that
succeeds to load is used. If all fails or there are no plugins, the built-in,
non-specialized integration is used.

To debug what integration is being used, enable the logging category
qt.qpa.egldeviceintegration.

There is some built-in logic for desktop/Mesa based systems: Under X,
eglfs_x11 is preferred, otherwise eglfs_kms is prioritized. This, assuming
sufficient permissions to video and input devices, allows simply launching
apps with -platform eglfs. No more editing of eglfs.pri.

[ChangeLog][QtGui] Added support for device-specific backend plugins in eglfs.

Change-Id: Ia2ddcddac014c25817171dc140cd8cf913784ac6
Reviewed-by: Louai Al-Khanji <louai.al-khanji@theqtcompany.com>

1 files changed, 294 insertions, 0 deletions

diff --git a/src/plugins/platforms/eglfs/deviceintegration/eglfs_x11/qeglfsx11integration.cpp b/src/plugins/platforms/eglfs/deviceintegration/eglfs_x11/qeglfsx11integration.cpp
new file mode 100644
index 0000000000..0ce5e341bf
--- /dev/null
+++ b/src/plugins/platforms/eglfs/deviceintegration/eglfs_x11/qeglfsx11integration.cpp
@@ -0,0 +1,294 @@
+/****************************************************************************
+**
+** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the plugins of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL21$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Digia. For licensing terms and
+** conditions see http://qt.digia.com/licensing. For further information
+** use the contact form at http://qt.digia.com/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 or version 3 as published by the Free
+** Software Foundation and appearing in the file LICENSE.LGPLv21 and
+** LICENSE.LGPLv3 included in the packaging of this file. Please review the
+** following information to ensure the GNU Lesser General Public License
+** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights. These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qeglfsx11integration.h"
+#include <QThread>
+
+#include <X11/Xlib.h>
+#include <X11/Xlib-xcb.h>
+
+/* Make no mistake: This is not a replacement for the xcb platform plugin.
+   This here is barely an extremely useful tool for developing eglfs itself because
+   it allows to do so without any requirements for devices or drivers. */
+
+QT_BEGIN_NAMESPACE
+
+class EventReader : public QThread
+{
+public:
+    EventReader(QEglFSX11Integration *integration)
+        : m_integration(integration) { }
+
+    void run();
+
+private:
+    QEglFSX11Integration *m_integration;
+};
+
+QAtomicInt running;
+
+static Qt::MouseButtons translateMouseButtons(int s)
+{
+    Qt::MouseButtons ret = 0;
+    if (s & XCB_BUTTON_MASK_1)
+        ret |= Qt::LeftButton;
+    if (s & XCB_BUTTON_MASK_2)
+        ret |= Qt::MidButton;
+    if (s & XCB_BUTTON_MASK_3)
+        ret |= Qt::RightButton;
+    return ret;
+}
+
+static Qt::MouseButton translateMouseButton(xcb_button_t s)
+{
+    switch (s) {
+    case 1: return Qt::LeftButton;
+    case 2: return Qt::MidButton;
+    case 3: return Qt::RightButton;
+    // Button values 4-7 were already handled as Wheel events, and won't occur here.
+    case 8: return Qt::BackButton;      // Also known as Qt::ExtraButton1
+    case 9: return Qt::ForwardButton;   // Also known as Qt::ExtraButton2
+    case 10: return Qt::ExtraButton3;
+    case 11: return Qt::ExtraButton4;
+    case 12: return Qt::ExtraButton5;
+    case 13: return Qt::ExtraButton6;
+    case 14: return Qt::ExtraButton7;
+    case 15: return Qt::ExtraButton8;
+    case 16: return Qt::ExtraButton9;
+    case 17: return Qt::ExtraButton10;
+    case 18: return Qt::ExtraButton11;
+    case 19: return Qt::ExtraButton12;
+    case 20: return Qt::ExtraButton13;
+    case 21: return Qt::ExtraButton14;
+    case 22: return Qt::ExtraButton15;
+    case 23: return Qt::ExtraButton16;
+    case 24: return Qt::ExtraButton17;
+    case 25: return Qt::ExtraButton18;
+    case 26: return Qt::ExtraButton19;
+    case 27: return Qt::ExtraButton20;
+    case 28: return Qt::ExtraButton21;
+    case 29: return Qt::ExtraButton22;
+    case 30: return Qt::ExtraButton23;
+    case 31: return Qt::ExtraButton24;
+    default: return Qt::NoButton;
+    }
+}
+
+void EventReader::run()
+{
+    Qt::MouseButtons buttons;
+
+    xcb_generic_event_t *event;
+    while (running.load() && (event = xcb_wait_for_event(m_integration->connection()))) {
+        uint response_type = event->response_type & ~0x80;
+        switch (response_type) {
+        case XCB_BUTTON_PRESS: {
+            xcb_button_press_event_t *press = (xcb_button_press_event_t *)event;
+            QPoint p(press->event_x, press->event_y);
+            buttons = (buttons & ~0x7) | translateMouseButtons(press->state);
+            buttons |= translateMouseButton(press->detail);
+            QWindowSystemInterface::handleMouseEvent(0, press->time, p, p, buttons);
+            break;
+            }
+        case XCB_BUTTON_RELEASE: {
+            xcb_button_release_event_t *release = (xcb_button_release_event_t *)event;
+            QPoint p(release->event_x, release->event_y);
+            buttons = (buttons & ~0x7) | translateMouseButtons(release->state);
+            buttons &= ~translateMouseButton(release->detail);
+            QWindowSystemInterface::handleMouseEvent(0, release->time, p, p, buttons);
+            break;
+            }
+        case XCB_MOTION_NOTIFY: {
+            xcb_motion_notify_event_t *motion = (xcb_motion_notify_event_t *)event;
+            QPoint p(motion->event_x, motion->event_y);
+            QWindowSystemInterface::handleMouseEvent(0, motion->time, p, p, buttons);
+            break;
+            }
+        case XCB_CLIENT_MESSAGE: {
+            xcb_client_message_event_t *client = (xcb_client_message_event_t *) event;
+            const xcb_atom_t *atoms = m_integration->atoms();
+            if (client->format == 32
+                && client->type == atoms[Atoms::WM_PROTOCOLS]
+                && client->data.data32[0] == atoms[Atoms::WM_DELETE_WINDOW]) {
+                QWindow *window = m_integration->platformWindow() ? m_integration->platformWindow()->window() : 0;
+                if (window)
+                    QWindowSystemInterface::handleCloseEvent(window);
+            }
+            break;
+            }
+        default:
+            break;
+        }
+    }
+}
+
+void QEglFSX11Integration::sendConnectionEvent(xcb_atom_t a)
+{
+    xcb_client_message_event_t event;
+    memset(&event, 0, sizeof(event));
+
+    event.response_type = XCB_CLIENT_MESSAGE;
+    event.format = 32;
+    event.sequence = 0;
+    event.window = m_connectionEventListener;
+    event.type = a;
+
+    xcb_send_event(m_connection, false, m_connectionEventListener, XCB_EVENT_MASK_NO_EVENT, (const char *)&event);
+    xcb_flush(m_connection);
+}
+
+#define DISPLAY ((Display *) m_display)
+
+void QEglFSX11Integration::platformInit()
+{
+    m_display = XOpenDisplay(0);
+    if (!m_display)
+        qFatal("Could not open display");
+
+    XSetEventQueueOwner(DISPLAY, XCBOwnsEventQueue);
+    m_connection = XGetXCBConnection(DISPLAY);
+
+    running.ref();
+
+    xcb_screen_iterator_t it = xcb_setup_roots_iterator(xcb_get_setup(m_connection));
+
+    m_connectionEventListener = xcb_generate_id(m_connection);
+    xcb_create_window(m_connection, XCB_COPY_FROM_PARENT,
+                      m_connectionEventListener, it.data->root,
+                      0, 0, 1, 1, 0, XCB_WINDOW_CLASS_INPUT_ONLY,
+                      it.data->root_visual, 0, 0);
+
+    m_eventReader = new EventReader(this);
+    m_eventReader->start();
+}
+
+void QEglFSX11Integration::platformDestroy()
+{
+    running.deref();
+
+    sendConnectionEvent(XCB_ATOM_NONE);
+
+    m_eventReader->wait();
+    delete m_eventReader;
+    m_eventReader = 0;
+
+    XCloseDisplay(DISPLAY);
+    m_display = 0;
+    m_connection = 0;
+}
+
+EGLNativeDisplayType QEglFSX11Integration::platformDisplay() const
+{
+    return DISPLAY;
+}
+
+QSize QEglFSX11Integration::screenSize() const
+{
+    if (m_screenSize.isEmpty()) {
+        QList<QByteArray> env = qgetenv("EGLFS_X11_SIZE").split('x');
+        if (env.length() == 2) {
+            m_screenSize = QSize(env.at(0).toInt(), env.at(1).toInt());
+        } else {
+            m_screenSize = QSize(640, 480);
+            qWarning("EGLFS_X11_SIZE not set, falling back to 640x480");
+        }
+    }
+    return m_screenSize;
+}
+
+EGLNativeWindowType QEglFSX11Integration::createNativeWindow(QPlatformWindow *platformWindow,
+                                                       const QSize &size,
+                                                       const QSurfaceFormat &format)
+{
+    Q_UNUSED(format);
+
+    m_platformWindow = platformWindow;
+
+    xcb_screen_iterator_t it = xcb_setup_roots_iterator(xcb_get_setup(m_connection));
+    m_window = xcb_generate_id(m_connection);
+    xcb_create_window(m_connection, XCB_COPY_FROM_PARENT, m_window, it.data->root,
+                      0, 0, size.width(), size.height(), 0,
+                      XCB_WINDOW_CLASS_INPUT_OUTPUT, it.data->root_visual,
+                      0, 0);
+
+    xcb_map_window(m_connection, m_window);
+
+    xcb_intern_atom_cookie_t cookies[Atoms::N_ATOMS];
+    static const char *atomNames[Atoms::N_ATOMS] = {
+        "_NET_WM_NAME",
+        "UTF8_STRING",
+        "WM_PROTOCOLS",
+        "WM_DELETE_WINDOW",
+        "_NET_WM_STATE",
+        "_NET_WM_STATE_FULLSCREEN"
+    };
+
+    for (int i = 0; i < Atoms::N_ATOMS; ++i) {
+        cookies[i] = xcb_intern_atom(m_connection, false, strlen(atomNames[i]), atomNames[i]);
+        xcb_intern_atom_reply_t *reply = xcb_intern_atom_reply(m_connection, cookies[i], 0);
+        m_atoms[i] = reply->atom;
+        free(reply);
+    }
+
+    // Set window title
+    xcb_change_property(m_connection, XCB_PROP_MODE_REPLACE, m_window,
+                        m_atoms[Atoms::_NET_WM_NAME], m_atoms[Atoms::UTF8_STRING], 8, 5, "EGLFS");
+
+    // Enable WM_DELETE_WINDOW
+    xcb_change_property(m_connection, XCB_PROP_MODE_REPLACE, m_window,
+                        m_atoms[Atoms::WM_PROTOCOLS], XCB_ATOM_ATOM, 32, 1, &m_atoms[Atoms::WM_DELETE_WINDOW]);
+
+    if (qEnvironmentVariableIntValue("EGLFS_X11_FULLSCREEN")) {
+        // Go fullscreen. The QScreen and QWindow size is controlled by EGLFS_X11_SIZE regardless,
+        // this is just the native window.
+        xcb_change_property(m_connection, XCB_PROP_MODE_REPLACE, m_window,
+                            m_atoms[Atoms::_NET_WM_STATE], XCB_ATOM_ATOM, 32, 1, &m_atoms[Atoms::_NET_WM_STATE_FULLSCREEN]);
+    }
+
+    xcb_flush(m_connection);
+
+    return m_window;
+}
+
+void QEglFSX11Integration::destroyNativeWindow(EGLNativeWindowType window)
+{
+    xcb_destroy_window(m_connection, window);
+}
+
+bool QEglFSX11Integration::hasCapability(QPlatformIntegration::Capability cap) const
+{
+    Q_UNUSED(cap);
+    return false;
+}
+
+QT_END_NAMESPACE