path: root/src/plugins/platforms/windows/qwindowscontext.cpp

/****************************************************************************
**
** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/
**
** This file is part of the plugins 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.
**
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** $QT_END_LICENSE$
**
****************************************************************************/

#include "qwindowscontext.h"
#include "qwindowswindow.h"
#include "qwindowskeymapper.h"
#include "qwindowsguieventdispatcher.h"
#include "qwindowsmousehandler.h"
#include "qtwindowsglobal.h"
#include "qwindowsmime.h"
#include "qwindowsinputcontext.h"
#ifndef QT_NO_ACCESSIBILITY
#include "accessible/qwindowsaccessibility.h"
#endif
#include "qwindowsscreen.h"
#include "qwindowstheme.h"

#include <QtGui/QWindow>
#include <QtGui/QWindowSystemInterface>
#include <QtGui/QPlatformNativeInterface>
#include <QtGui/QGuiApplication>

#include <QtCore/QSet>
#include <QtCore/QHash>
#include <QtCore/QStringList>
#include <QtCore/QDebug>
#include <QtCore/QSysInfo>
#include <QtCore/QScopedArrayPointer>
#include <QtCore/private/qsystemlibrary_p.h>

#include <stdlib.h>
#include <stdio.h>
#include <windowsx.h>

QT_BEGIN_NAMESPACE

// Verbosity of components
int QWindowsContext::verboseIntegration = 0;
int QWindowsContext::verboseWindows = 0;
int QWindowsContext::verboseEvents = 0;
int QWindowsContext::verboseBackingStore = 0;
int QWindowsContext::verboseFonts = 0;
int QWindowsContext::verboseGL = 0;
int QWindowsContext::verboseOLE = 0;
int QWindowsContext::verboseInputMethods = 0;
int QWindowsContext::verboseDialogs = 0;
int QWindowsContext::verboseTheming = 0;

// Get verbosity of components from "foo:2,bar:3"
static inline int componentVerbose(const char *v, const char *keyWord)
{
    if (const char *k = strstr(v, keyWord)) {
        k += qstrlen(keyWord);
        if (*k == ':') {
            ++k;
            if (isdigit(*k))
                return *k - '0';
        }
    }
    return 0;
}

static inline bool hasTouchSupport(QSysInfo::WinVersion wv)
{
    enum { QT_SM_DIGITIZER = 94, QT_NID_INTEGRATED_TOUCH = 0x1,
           QT_NID_EXTERNAL_TOUCH = 0x02, QT_NID_MULTI_INPUT = 0x40 };

    return wv < QSysInfo::WV_WINDOWS7 ? false :
           (GetSystemMetrics(QT_SM_DIGITIZER) & (QT_NID_INTEGRATED_TOUCH | QT_NID_EXTERNAL_TOUCH | QT_NID_MULTI_INPUT)) != 0;
}

#if !defined(LANG_SYRIAC)
#    define LANG_SYRIAC 0x5a
#endif

static inline bool useRTL_Extensions(QSysInfo::WinVersion ver)
{
    if ((ver & QSysInfo::WV_NT_based) && (ver >= QSysInfo::WV_VISTA)) {
        // Since the IsValidLanguageGroup/IsValidLocale functions always return true on
        // Vista, check the Keyboard Layouts for enabling RTL.
        if (const UINT nLayouts = GetKeyboardLayoutList(0, 0)) {
            QScopedArrayPointer<HKL> lpList(new HKL[nLayouts]);
            GetKeyboardLayoutList(nLayouts, lpList.data());
            for (UINT i = 0; i < nLayouts; ++i) {
                switch (PRIMARYLANGID((quintptr)lpList[i])) {
                case LANG_ARABIC:
                case LANG_HEBREW:
                case LANG_FARSI:
                case LANG_SYRIAC:
                    return true;
                default:
                    break;
                }
            }
        }
        return false;
    } // NT/Vista
    // Pre-NT: figure out whether a RTL language is installed
    return IsValidLanguageGroup(LGRPID_ARABIC, LGRPID_INSTALLED)
                            || IsValidLanguageGroup(LGRPID_HEBREW, LGRPID_INSTALLED)
                            || IsValidLocale(MAKELCID(MAKELANGID(LANG_ARABIC, SUBLANG_DEFAULT), SORT_DEFAULT), LCID_INSTALLED)
                            || IsValidLocale(MAKELCID(MAKELANGID(LANG_HEBREW, SUBLANG_DEFAULT), SORT_DEFAULT), LCID_INSTALLED)
                            || IsValidLocale(MAKELCID(MAKELANGID(LANG_SYRIAC, SUBLANG_DEFAULT), SORT_DEFAULT), LCID_INSTALLED)
                            || IsValidLocale(MAKELCID(MAKELANGID(LANG_FARSI, SUBLANG_DEFAULT), SORT_DEFAULT), LCID_INSTALLED);
}

/*!
    \class QWindowsUser32DLL
    \brief Struct that contains dynamically resolved symbols of User32.dll.

    The stub libraries shipped with the MinGW compiler miss some of the
    functions. They need to be retrieved dynamically.

    In addition, touch-related functions are available only from Windows onwards.
    These need to resolved dynamically for Q_CC_MSVC as well.

    \sa QWindowsShell32DLL

    \ingroup qt-lighthouse-win
*/

QWindowsUser32DLL::QWindowsUser32DLL() :
    setLayeredWindowAttributes(0), updateLayeredWindow(0),
    updateLayeredWindowIndirect(0),
    isHungAppWindow(0),
    registerTouchWindow(0), getTouchInputInfo(0), closeTouchInputHandle(0)
{
}

void QWindowsUser32DLL::init()
{
    QSystemLibrary library(QStringLiteral("user32"));
    // MinGW (g++ 3.4.5) accepts only C casts.
    setLayeredWindowAttributes = (SetLayeredWindowAttributes)(library.resolve("SetLayeredWindowAttributes"));
    updateLayeredWindow = (UpdateLayeredWindow)(library.resolve("UpdateLayeredWindow"));
    if (!setLayeredWindowAttributes || !updateLayeredWindow)
        qFatal("This version of Windows is not supported (User32.dll is missing the symbols 'SetLayeredWindowAttributes', 'UpdateLayeredWindow').");

    updateLayeredWindowIndirect = (UpdateLayeredWindowIndirect)(library.resolve("UpdateLayeredWindowIndirect"));
    isHungAppWindow = (IsHungAppWindow)library.resolve("IsHungAppWindow");
}

bool QWindowsUser32DLL::initTouch()
{
    QSystemLibrary library(QStringLiteral("user32"));
    registerTouchWindow = (RegisterTouchWindow)(library.resolve("RegisterTouchWindow"));
    getTouchInputInfo = (GetTouchInputInfo)(library.resolve("GetTouchInputInfo"));
    closeTouchInputHandle = (CloseTouchInputHandle)(library.resolve("CloseTouchInputHandle"));
    return registerTouchWindow && getTouchInputInfo && getTouchInputInfo;
}

/*!
    \class QWindowsShell32DLL
    \brief Struct that contains dynamically resolved symbols of Shell32.dll.

    The stub libraries shipped with the MinGW compiler miss some of the
    functions. They need to be retrieved dynamically.

    \sa QWindowsUser32DLL

    \ingroup qt-lighthouse-win
*/

QWindowsShell32DLL::QWindowsShell32DLL() : sHCreateItemFromParsingName(0)
{
}

void QWindowsShell32DLL::init()
{
    QSystemLibrary library(QStringLiteral("shell32"));
    sHCreateItemFromParsingName = (SHCreateItemFromParsingName)(library.resolve("SHCreateItemFromParsingName"));
}

QWindowsUser32DLL QWindowsContext::user32dll;
QWindowsShell32DLL QWindowsContext::shell32dll;

QWindowsContext *QWindowsContext::m_instance = 0;

/*!
    \class QWindowsContext
    \brief Singleton container for all relevant information.

    Holds state information formerly stored in \c qapplication_win.cpp.
    \ingroup qt-lighthouse-win
*/

typedef QHash<HWND, QWindowsWindow *> HandleBaseWindowHash;

struct QWindowsContextPrivate {
    typedef QPlatformNativeInterface::EventFilter EventFilter;

    enum EventFilterType
    {
        GenericWindowsEventFilter,
        EventFilterTypeCount
    };

    QWindowsContextPrivate();

    unsigned m_systemInfo;
    QSet<QString> m_registeredWindowClassNames;
    HandleBaseWindowHash m_windows;
    HDC m_displayContext;
    const int m_defaultDPI;
    QWindowsKeyMapper m_keyMapper;
    QWindowsMouseHandler m_mouseHandler;
    QWindowsMimeConverter m_mimeConverter;
    QWindowsScreenManager m_screenManager;
    QSharedPointer<QWindowCreationContext> m_creationContext;
    const HRESULT m_oleInitializeResult;
    const QByteArray m_eventType;
    EventFilter m_eventFilters[EventFilterTypeCount];
};

QWindowsContextPrivate::QWindowsContextPrivate() :
    m_systemInfo(0),
    m_displayContext(GetDC(0)),
    m_defaultDPI(GetDeviceCaps(m_displayContext,LOGPIXELSY)),
    m_oleInitializeResult(OleInitialize(NULL)),
    m_eventType(QByteArrayLiteral("windows_generic_MSG"))
{
    QWindowsContext::user32dll.init();
    QWindowsContext::shell32dll.init();

    const QSysInfo::WinVersion ver = QSysInfo::windowsVersion();

    if (hasTouchSupport(ver) && QWindowsContext::user32dll.initTouch())
        m_systemInfo |= QWindowsContext::SI_SupportsTouch;

    if (useRTL_Extensions(ver)) {
        m_systemInfo |= QWindowsContext::SI_RTL_Extensions;
        m_keyMapper.setUseRTLExtensions(true);
    }
    qFill(m_eventFilters, m_eventFilters + EventFilterTypeCount, EventFilter(0));
}

QWindowsContext::QWindowsContext() :
    d(new QWindowsContextPrivate)
{
#ifdef Q_CC_MSVC
#    pragma warning( disable : 4996 )
#endif
    m_instance = this;
    if (const char *v = getenv("QT_QPA_VERBOSE")) {
        QWindowsContext::verboseIntegration = componentVerbose(v, "integration");
        QWindowsContext::verboseWindows = componentVerbose(v, "windows");
        QWindowsContext::verboseEvents = componentVerbose(v, "events");
        QWindowsContext::verboseBackingStore = componentVerbose(v, "backingstore");
        QWindowsContext::verboseFonts = componentVerbose(v, "fonts");
        QWindowsContext::verboseGL = componentVerbose(v, "gl");
        QWindowsContext::verboseOLE = componentVerbose(v, "ole");
        QWindowsContext::verboseInputMethods = componentVerbose(v, "im");
        QWindowsContext::verboseDialogs = componentVerbose(v, "dialogs");
        QWindowsContext::verboseTheming = componentVerbose(v, "theming");
    }
}

QWindowsContext::~QWindowsContext()
{
    unregisterWindowClasses();
    if (d->m_oleInitializeResult == S_OK || d->m_oleInitializeResult == S_FALSE)
        OleUninitialize();

    d->m_screenManager.clearScreens(); // Order: Potentially calls back to the windows.
    m_instance = 0;
}

QWindowsContext *QWindowsContext::instance()
{
    return m_instance;
}

unsigned QWindowsContext::systemInfo() const
{
    return d->m_systemInfo;
}

void QWindowsContext::setWindowCreationContext(const QSharedPointer<QWindowCreationContext> &ctx)
{
    d->m_creationContext = ctx;
}

int QWindowsContext::defaultDPI() const
{
    return d->m_defaultDPI;
}

HDC QWindowsContext::displayContext() const
{
    return d->m_displayContext;
}

QWindow *QWindowsContext::keyGrabber() const
{
    return d->m_keyMapper.keyGrabber();
}

void QWindowsContext::setKeyGrabber(QWindow *w)
{
    d->m_keyMapper.setKeyGrabber(w);
}

// Window class registering code (from qapplication_win.cpp)
// If 0 is passed as the widget pointer, register a window class
// for QWidget as default. This is used in QGLTemporaryContext
// during GL initialization, where we don't want to use temporary
// QWidgets or QGLWidgets, neither do we want to have separate code
// to register window classes.

QString QWindowsContext::registerWindowClass(const QWindow *w, bool isGL)
{
    const Qt::WindowFlags flags = w ? w->windowFlags() : (Qt::WindowFlags)0;
    const Qt::WindowFlags type = flags & Qt::WindowType_Mask;

    uint style = 0;
    bool icon = false;
    QString cname = QStringLiteral("Qt5");
    if (w && isGL) {
        cname += QStringLiteral("QGLWindow");
        style = CS_DBLCLKS|CS_OWNDC;
        icon  = true;
    } else if (w && (flags & Qt::MSWindowsOwnDC)) {
        cname += QStringLiteral("QWindowOwnDC");
        style = CS_DBLCLKS|CS_OWNDC;
        icon  = true;
    } else if (w && (type == Qt::Tool || type == Qt::ToolTip)) {
        style = CS_DBLCLKS;
        if (w->inherits("QTipLabel") || w->inherits("QAlphaWidget")) {
            if ((QSysInfo::WindowsVersion >= QSysInfo::WV_XP
                && (QSysInfo::WindowsVersion & QSysInfo::WV_NT_based))) {
                style |= CS_DROPSHADOW;
            }
            cname += QStringLiteral("QToolTip");
        } else {
            cname += QStringLiteral("QTool");
        }
        style |= CS_SAVEBITS;
        icon = false;
    } else if (w && (type == Qt::Popup)) {
        cname += QStringLiteral("QPopup");
        style = CS_DBLCLKS|CS_SAVEBITS;
        if ((QSysInfo::WindowsVersion >= QSysInfo::WV_XP
            && (QSysInfo::WindowsVersion & QSysInfo::WV_NT_based)))
            style |= CS_DROPSHADOW;
        icon = false;
    } else {
        cname += QStringLiteral("QWindow");
        style = CS_DBLCLKS;
        icon  = true;
    }

    HBRUSH brush = 0;
    if (w && !isGL)
        brush = GetSysColorBrush(COLOR_WINDOW);
    return registerWindowClass(cname, qWindowsWndProc, style, brush, icon);
}

QString QWindowsContext::registerWindowClass(QString cname,
                                             WNDPROC proc,
                                             unsigned style,
                                             HBRUSH brush,
                                             bool icon)
{
    // since multiple Qt versions can be used in one process
    // each one has to have window class names with a unique name
    // The first instance gets the unmodified name; if the class
    // has already been registered by another instance of Qt then
    // add an instance-specific ID, the address of the window proc.
    static int classExists = -1;

    const HINSTANCE appInstance = (HINSTANCE)GetModuleHandle(0);
    if (classExists == -1) {
        WNDCLASS wcinfo;
        classExists = GetClassInfo(appInstance, (wchar_t*)cname.utf16(), &wcinfo);
        classExists = classExists && wcinfo.lpfnWndProc != proc;
    }

    if (classExists)
        cname += QString::number((quintptr)proc);

    if (d->m_registeredWindowClassNames.contains(cname))        // already registered in our list
        return cname;

    WNDCLASSEX wc;
    wc.cbSize       = sizeof(WNDCLASSEX);
    wc.style        = style;
    wc.lpfnWndProc  = proc;
    wc.cbClsExtra   = 0;
    wc.cbWndExtra   = 0;
    wc.hInstance    = appInstance;
    if (icon) {
        wc.hIcon = (HICON)LoadImage(appInstance, L"IDI_ICON1", IMAGE_ICON, 0, 0, LR_DEFAULTSIZE);
        if (wc.hIcon) {
            int sw = GetSystemMetrics(SM_CXSMICON);
            int sh = GetSystemMetrics(SM_CYSMICON);
            wc.hIconSm = (HICON)LoadImage(appInstance, L"IDI_ICON1", IMAGE_ICON, sw, sh, 0);
        } else {
            wc.hIcon = (HICON)LoadImage(0, IDI_APPLICATION, IMAGE_ICON, 0, 0, LR_DEFAULTSIZE | LR_SHARED);
            wc.hIconSm = 0;
        }
    } else {
        wc.hIcon    = 0;
        wc.hIconSm  = 0;
    }
    wc.hCursor      = 0;
    wc.hbrBackground = brush;
    wc.lpszMenuName  = 0;
    wc.lpszClassName = (wchar_t*)cname.utf16();
    ATOM atom = RegisterClassEx(&wc);

    if (!atom)
        qErrnoWarning("QApplication::regClass: Registering window class '%s' failed.",
                      qPrintable(cname));

    d->m_registeredWindowClassNames.insert(cname);
    if (QWindowsContext::verboseIntegration || QWindowsContext::verboseWindows)
        qDebug().nospace() << __FUNCTION__ << ' ' << cname
                 << " style=0x" << QString::number(style, 16)
                 << " brush=" << brush << " icon=" << icon << " atom=" << atom;
    return cname;
}

void QWindowsContext::unregisterWindowClasses()
{
    const HINSTANCE appInstance = (HINSTANCE)GetModuleHandle(0);

    foreach (const QString &name,  d->m_registeredWindowClassNames) {
        if (QWindowsContext::verboseIntegration)
            qDebug() << __FUNCTION__ << name;
        UnregisterClass((wchar_t*)name.utf16(), appInstance);
    }
    d->m_registeredWindowClassNames.clear();
}

int QWindowsContext::screenDepth() const
{
    return GetDeviceCaps(d->m_displayContext, BITSPIXEL);
}

QString QWindowsContext::windowsErrorMessage(unsigned long errorCode)
{
    QString rc = QString::fromLatin1("#%1: ").arg(errorCode);
    ushort *lpMsgBuf;

    const int len = FormatMessage(
            FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
            NULL, errorCode, 0, (LPTSTR)&lpMsgBuf, 0, NULL);
    if (len) {
        rc = QString::fromUtf16(lpMsgBuf, len);
        LocalFree(lpMsgBuf);
    } else {
        rc += QString::fromLatin1("<unknown error>");
    }
    return rc;
}

void QWindowsContext::addWindow(HWND hwnd, QWindowsWindow *w)
{
    d->m_windows.insert(hwnd, w);
}

void QWindowsContext::removeWindow(HWND hwnd)
{
    const HandleBaseWindowHash::iterator it = d->m_windows.find(hwnd);
    if (it != d->m_windows.end()) {
        if (d->m_keyMapper.keyGrabber() == it.value()->window())
            d->m_keyMapper.setKeyGrabber(0);
        d->m_windows.erase(it);
    }
}

QWindowsWindow *QWindowsContext::findPlatformWindow(HWND hwnd) const
{
    return d->m_windows.value(hwnd);
}

QWindow *QWindowsContext::findWindow(HWND hwnd) const
{
    if (const QWindowsWindow *bw = findPlatformWindow(hwnd))
            return bw->window();
    return 0;
}

QWindow *QWindowsContext::windowUnderMouse() const
{
    return d->m_mouseHandler.windowUnderMouse();
}

/*!
    \brief Find a child window at a screen point.

    Deep search for a QWindow at global point, skipping non-owned
    windows (accessibility?). Implemented using ChildWindowFromPointEx()
    instead of (historically used) WindowFromPoint() to get a well-defined
    behaviour for hidden/transparent windows.

    \a cwex_flags are flags of ChildWindowFromPointEx().
    \a parent is the parent window, pass GetDesktopWindow() for top levels.
*/

QWindowsWindow *QWindowsContext::findPlatformWindowAt(HWND parent,
                                                          const QPoint &screenPointIn,
                                                          unsigned cwex_flags) const
{
    QWindowsWindow *result = 0;
    const POINT screenPoint = { screenPointIn.x(), screenPointIn.y() };
    while (true) {
        POINT point = screenPoint;
        ScreenToClient(parent, &point);
        // Returns parent if inside & none matched.
        const HWND child = ChildWindowFromPointEx(parent, point, cwex_flags);
        if (child && child != parent) {
            if (QWindowsWindow *window = findPlatformWindow(child))
                result = window;
            parent = child;
        } else {
            break;
        }
    }
    return result;
}

QWindowsMimeConverter &QWindowsContext::mimeConverter() const
{
    return d->m_mimeConverter;
}

QWindowsScreenManager &QWindowsContext::screenManager()
{
    return d->m_screenManager;
}

/*!
    \brief Convenience to create a non-visible, message-only dummy
    window for example used as clipboard watcher or for GL.
*/

HWND QWindowsContext::createDummyWindow(const QString &classNameIn,
                                        const wchar_t *windowName,
                                        WNDPROC wndProc, DWORD style)
{
    if (!wndProc)
        wndProc = DefWindowProc;
    QString className = registerWindowClass(classNameIn, wndProc);
    return CreateWindowEx(0, (wchar_t*)className.utf16(),
                          windowName, style,
                          CW_USEDEFAULT, CW_USEDEFAULT,
                          CW_USEDEFAULT, CW_USEDEFAULT,
                          HWND_MESSAGE, NULL, (HINSTANCE)GetModuleHandle(0), NULL);
}

/*!
    \brief Common COM error strings.
*/

QByteArray QWindowsContext::comErrorString(HRESULT hr)
{
    switch (hr) {
    case S_OK:
        return QByteArrayLiteral("S_OK");
    case S_FALSE:
        return QByteArrayLiteral("S_FALSE");
    case E_UNEXPECTED:
        return QByteArrayLiteral("E_UNEXPECTED");
    case CO_E_ALREADYINITIALIZED:
        return QByteArrayLiteral("CO_E_ALREADYINITIALIZED");
    case CO_E_NOTINITIALIZED:
        return QByteArrayLiteral("CO_E_NOTINITIALIZED");
    case RPC_E_CHANGED_MODE:
        return QByteArrayLiteral("RPC_E_CHANGED_MODE");
    case OLE_E_WRONGCOMPOBJ:
        return QByteArrayLiteral("OLE_E_WRONGCOMPOBJ");
    case CO_E_NOT_SUPPORTED:
        return QByteArrayLiteral("CO_E_NOT_SUPPORTED");
    case E_NOTIMPL:
        return QByteArrayLiteral("E_NOTIMPL");
    case E_INVALIDARG:
        return QByteArrayLiteral("E_INVALIDARG");
    case E_NOINTERFACE:
        return QByteArrayLiteral("E_NOINTERFACE");
    case E_POINTER:
        return QByteArrayLiteral("E_POINTER");
    case E_HANDLE:
        return QByteArrayLiteral("E_HANDLE");
    case E_ABORT:
        return QByteArrayLiteral("E_ABORT");
    case E_FAIL:
        return QByteArrayLiteral("E_FAIL");
    case RPC_E_WRONG_THREAD:
        return QByteArrayLiteral("RPC_E_WRONG_THREAD");
    case RPC_E_THREAD_NOT_INIT:
        return QByteArrayLiteral("RPC_E_THREAD_NOT_INIT");
    default:
        break;
    }
    return "Unknown error 0x" + QByteArray::number(quint64(hr), 16);
}

/*!
     \brief Set event filter.

     \sa QWindowsNativeInterface
*/

QWindowsContext::EventFilter QWindowsContext::setEventFilter(const QByteArray &eventType, EventFilter filter)
{
    int eventFilterType = -1;
    if (eventType == d->m_eventType)
        eventFilterType = QWindowsContextPrivate::GenericWindowsEventFilter;
    if (eventFilterType < 0) {
        qWarning("%s: Attempt to set unsupported event filter '%s'.",
                 __FUNCTION__, eventType.constData());
        return 0;
    }
    const EventFilter previous = d->m_eventFilters[eventFilterType];
    d->m_eventFilters[eventFilterType] = filter;
    return previous;
}

/*!
     \brief Main windows procedure registered for windows.

     \sa QWindowsGuiEventDispatcher
*/

bool QWindowsContext::windowsProc(HWND hwnd, UINT message,
                                  QtWindows::WindowsEventType et,
                                  WPARAM wParam, LPARAM lParam, LRESULT *result)
{
    *result = 0;

    MSG msg;
    msg.hwnd = hwnd;         // re-create MSG structure
    msg.message = message;   // time and pt fields ignored
    msg.wParam = wParam;
    msg.lParam = lParam;
    msg.pt.x = GET_X_LPARAM(lParam);
    msg.pt.y = GET_Y_LPARAM(lParam);

    long filterResult = 0;
    if (d->m_eventFilters[QWindowsContextPrivate::GenericWindowsEventFilter]) {
        if (d->m_eventFilters[QWindowsContextPrivate::GenericWindowsEventFilter](&msg, &filterResult)) {
            *result = LRESULT(filterResult);
            return true;
        }
    }
    // Events without an associated QWindow or events we are not interested in.
    switch (et) {
    case QtWindows::InputMethodStartCompositionEvent:
        return QWindowsInputContext::instance()->startComposition(hwnd);
    case QtWindows::InputMethodCompositionEvent:
        return QWindowsInputContext::instance()->composition(hwnd, lParam);
    case QtWindows::InputMethodEndCompositionEvent:
        return QWindowsInputContext::instance()->endComposition(hwnd);
    case QtWindows::InputMethodRequest:
        return QWindowsInputContext::instance()->handleIME_Request(wParam, lParam, result);
    case QtWindows::InputMethodOpenCandidateWindowEvent:
    case QtWindows::InputMethodCloseCandidateWindowEvent:
        // TODO: Release/regrab mouse if a popup has mouse grab.
        return false;
    case QtWindows::ClipboardEvent:
    case QtWindows::DestroyEvent:

    case QtWindows::UnknownEvent:
        return false;
    case QtWindows::AccessibleObjectFromWindowRequest:
#ifndef QT_NO_ACCESSIBILITY
        return QWindowsAccessibility::handleAccessibleObjectFromWindowRequest(hwnd, wParam, lParam, result);
#else
        return false;
#endif
    case QtWindows::DisplayChangedEvent:
        return d->m_screenManager.handleDisplayChange(wParam, lParam);
    default:
        break;
    }

    QWindowsWindow *platformWindow = findPlatformWindow(hwnd);
    // Before CreateWindowEx() returns, some events are sent,
    // for example WM_GETMINMAXINFO asking for size constraints for top levels.
    // Pass on to current creation context
    if (!platformWindow && !d->m_creationContext.isNull()) {
        switch (et) {
        case QtWindows::QuerySizeHints:
            d->m_creationContext->applyToMinMaxInfo(reinterpret_cast<MINMAXINFO *>(lParam));
            return true;
        case QtWindows::ResizeEvent:
            d->m_creationContext->obtainedGeometry.setSize(QSize(GET_X_LPARAM(lParam), GET_Y_LPARAM(lParam)));
            return true;
        case QtWindows::MoveEvent:
            d->m_creationContext->obtainedGeometry.moveTo(GET_X_LPARAM(lParam), GET_Y_LPARAM(lParam));
            return true;
        case QtWindows::CalculateSize:
            return false;
        default:
            break;
        }
    }
    if (platformWindow) {
        if (QWindowsContext::verboseEvents > 1)
            qDebug().nospace() << "Event window: " << platformWindow->window();
    } else {
        qWarning("%s: No Qt Window found for event 0x%x (%s), hwnd=0x%p.",
                 __FUNCTION__, message,
                 QWindowsGuiEventDispatcher::windowsMessageName(message), hwnd);
        return false;
    }

    filterResult = 0;
    if (QWindowSystemInterface::handleNativeEvent(platformWindow->window(), d->m_eventType, &msg, &filterResult)) {
        *result = LRESULT(filterResult);
        return true;
    }

    switch (et) {
    case QtWindows::KeyDownEvent:
    case QtWindows::KeyEvent:
    case QtWindows::InputMethodKeyEvent:
    case QtWindows::InputMethodKeyDownEvent:
        return d->m_keyMapper.translateKeyEvent(platformWindow->window(), hwnd, msg, result);
    case QtWindows::MoveEvent:
        platformWindow->handleMoved();
        return true;
    case QtWindows::ResizeEvent:
        platformWindow->handleResized((int)wParam);
        return true;
    case QtWindows::QuerySizeHints:
        platformWindow->getSizeHints(reinterpret_cast<MINMAXINFO *>(lParam));
        return true;
    case QtWindows::CalculateSize:
        // NCCALCSIZE_PARAMS structure if wParam==TRUE
        if (wParam && QWindowsContext::verboseWindows) {
            const NCCALCSIZE_PARAMS *ncp = reinterpret_cast<NCCALCSIZE_PARAMS *>(lParam);
            qDebug() << platformWindow->window() << *ncp;
        }
        break;
    case QtWindows::ExposeEvent:
        return platformWindow->handleWmPaint(hwnd, message, wParam, lParam);
    case QtWindows::MouseWheelEvent:
    case QtWindows::MouseEvent:
    case QtWindows::NonClientMouseEvent:
    case QtWindows::LeaveEvent:
        return d->m_mouseHandler.translateMouseEvent(platformWindow->window(), hwnd, et, msg, result);
    case QtWindows::TouchEvent:
        return d->m_mouseHandler.translateTouchEvent(platformWindow->window(), hwnd, et, msg, result);
    case QtWindows::FocusInEvent: // see QWindowsWindow::requestActivateWindow().
        QWindowSystemInterface::handleWindowActivated(platformWindow->window());
        return true;
    case QtWindows::FocusOutEvent:
        QWindowSystemInterface::handleWindowActivated(0);
        return true;
    case QtWindows::ShowEvent:
        platformWindow->handleShown();
        return true;
    case QtWindows::HideEvent:
        platformWindow->handleHidden();
        return true;
    case QtWindows::CloseEvent:
        QWindowSystemInterface::handleCloseEvent(platformWindow->window());
        return true;
    case QtWindows::ThemeChanged: // ### fixme: Compress these events?
        if (QWindowsTheme *theme = QWindowsTheme::instance())
            theme->windowsThemeChanged(platformWindow->window());
        return true;
    case QtWindows::ActivateWindowEvent:
        if (platformWindow->testFlag(QWindowsWindow::BlockedByModal))
            if (const QWindow *modalWindow = QGuiApplication::modalWindow())
                QWindowsWindow::baseWindowOf(modalWindow)->alertWindow();
        break;
    default:
        break;
    }
    return false;
}

/*!
    \brief Windows functions for actual windows.

    There is another one for timers, sockets, etc in
    QEventDispatcherWin32.

    \ingroup qt-lighthouse-win
*/

extern "C" LRESULT QT_WIN_CALLBACK qWindowsWndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    LRESULT result;
    const QtWindows::WindowsEventType et = windowsEventType(message, wParam);
    const bool handled = QWindowsContext::instance()->windowsProc(hwnd, message, et, wParam, lParam, &result);
    if (QWindowsContext::verboseEvents > 1)
        if (const char *eventName = QWindowsGuiEventDispatcher::windowsMessageName(message))
            qDebug("EVENT: hwd=%p %s msg=0x%x et=0x%x wp=%d at %d,%d handled=%d",
                   hwnd, eventName, message, et, int(wParam),
                   GET_X_LPARAM(lParam), GET_Y_LPARAM(lParam), handled);
    if (!handled)
        result = DefWindowProc(hwnd, message, wParam, lParam);
    return result;
}

QT_END_NAMESPACE