Add QWinMime.

Add class QWinMime (equivalent to WindowsMime in Qt 4).

[ChangeLog][QWinMime] Added abstract class QWinMime (equivalent
to WindowsMime in Qt 4) for registering custom mime type
conversions.

Task-number: QTBUG-39559
Change-Id: Ie8ff4db6cd0ce64f65b83232dc91d771238663d1
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>

3 files changed, 274 insertions, 2 deletions

diff --git a/src/winextras/qwinmime.cpp b/src/winextras/qwinmime.cpp
new file mode 100644
index 0000000..73d109a
--- /dev/null
+++ b/src/winextras/qwinmime.cpp
@@ -0,0 +1,190 @@
+/****************************************************************************
+**
+** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the QtWinExtras module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** 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 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, 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.
+**
+** 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.
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qwinmime.h"
+
+#include <QtGui/QGuiApplication>
+#include <QtCore/QMetaObject>
+#include <QtCore/QDebug>
+
+#include <qpa/qplatformnativeinterface.h>
+
+QT_BEGIN_NAMESPACE
+
+/*!
+    \class QWinMime
+    \inmodule QtWinExtras
+    \brief The QWinMime class maps open-standard MIME to Window Clipboard formats.
+
+    Qt's drag-and-drop and clipboard facilities use the MIME standard.
+    On X11, this maps trivially to the Xdnd protocol, but on Windows
+    although some applications use MIME types to describe clipboard
+    formats, others use arbitrary non-standardized naming conventions,
+    or unnamed built-in formats of Windows.
+
+    By instantiating subclasses of QWinMime that provide conversions
+    between Windows Clipboard and MIME formats, you can convert
+    proprietary clipboard formats to MIME formats.
+
+    Qt has predefined support for the following Windows Clipboard formats:
+
+    \table
+    \header \li Windows Format \li Equivalent MIME type
+    \row \li \c CF_UNICODETEXT \li \c text/plain
+    \row \li \c CF_TEXT        \li \c text/plain
+    \row \li \c CF_DIB         \li \c{image/xyz}, where \c xyz is
+                                 a \l{QImageWriter::supportedImageFormats()}{Qt image format}
+    \row \li \c CF_HDROP       \li \c text/uri-list
+    \row \li \c CF_INETURL     \li \c text/uri-list
+    \row \li \c CF_HTML        \li \c text/html
+    \endtable
+
+    An example use of this class would be to map the Windows Metafile
+    clipboard format (\c CF_METAFILEPICT) to and from the MIME type
+    \c{image/x-wmf}. This conversion might simply be adding or removing
+    a header, or even just passing on the data. See \l{Drag and Drop}
+    for more information on choosing and definition MIME types.
+
+    You can check if a MIME type is convertible using canConvertFromMime() and
+    can perform conversions with convertToMime() and convertFromMime().
+
+    \since 5.4
+*/
+
+/*!
+    Constructs a new conversion object, adding it to the globally accessed
+    list of available converters.
+*/
+QWinMime::QWinMime()
+{
+    if (!QMetaObject::invokeMethod(QGuiApplication::platformNativeInterface(),
+                                   "registerWindowsMime", Q_ARG(void *, this))) {
+        qWarning() << Q_FUNC_INFO << "Unable to register mime type.";
+    }
+}
+
+/*!
+    Destroys a conversion object, removing it from the global
+    list of available converters.
+*/
+QWinMime::~QWinMime()
+{
+    if (!QMetaObject::invokeMethod(QGuiApplication::platformNativeInterface(),
+                                   "unregisterWindowsMime", Q_ARG(void *, this))) {
+        qWarning() << Q_FUNC_INFO << "Unable to unregister mime type.";
+    }
+}
+
+/*!
+    Registers the MIME type \a mime, and returns an ID number
+    identifying the format on Windows.
+*/
+int QWinMime::registerMimeType(const QString &mime)
+{
+    int result = 0;
+    if (!QMetaObject::invokeMethod(QGuiApplication::platformNativeInterface(),
+                                   "registerMimeType",
+                                   Q_RETURN_ARG(int, result),
+                                   Q_ARG(QString, mime))) {
+        qWarning() << Q_FUNC_INFO << "Unable to register mime type " << mime;
+    }
+    return result;
+}
+
+/*!
+    \fn bool QWinMime::canConvertFromMime(const FORMATETC &formatetc, const QMimeData *mimeData) const
+
+    Returns true if the converter can convert from the \a mimeData to
+    the format specified in \a formatetc.
+
+    All subclasses must reimplement this pure virtual function.
+*/
+
+/*!
+    \fn bool QWinMime::canConvertToMime(const QString &mimeType, IDataObject *pDataObj) const
+
+    Returns true if the converter can convert to the \a mimeType from
+    the available formats in \a pDataObj.
+
+    All subclasses must reimplement this pure virtual function.
+*/
+
+/*!
+    \fn QString QWinMime::mimeForFormat(const FORMATETC &formatetc) const
+
+    Returns the mime type that will be created form the format specified
+    in \a formatetc, or an empty string if this converter does not support
+    \a formatetc.
+
+    All subclasses must reimplement this pure virtual function.
+*/
+
+/*!
+    \fn QVector<FORMATETC> QWinMime::formatsForMime(const QString &mimeType, const QMimeData *mimeData) const
+
+    Returns a QVector of FORMATETC structures representing the different windows clipboard
+    formats that can be provided for the \a mimeType from the \a mimeData.
+
+    All subclasses must reimplement this pure virtual function.
+*/
+
+/*!
+    \fn QVariant QWinMime::convertToMime(const QString &mimeType, IDataObject *pDataObj,
+                                             QVariant::Type preferredType) const
+
+    Returns a QVariant containing the converted data for \a mimeType from \a pDataObj.
+    If possible the QVariant should be of the \a preferredType to avoid needless conversions.
+
+    All subclasses must reimplement this pure virtual function.
+*/
+
+/*!
+    \fn bool QWinMime::convertFromMime(const FORMATETC &formatetc, const QMimeData *mimeData, STGMEDIUM * pmedium) const
+
+    Convert the \a mimeData to the format specified in \a formatetc.
+    The converted data should then be placed in \a pmedium structure.
+
+    Return true if the conversion was successful.
+
+    All subclasses must reimplement this pure virtual function.
+*/
+
+QT_END_NAMESPACE
diff --git a/src/winextras/qwinmime.h b/src/winextras/qwinmime.h
new file mode 100644
index 0000000..633ad4d
--- /dev/null
+++ b/src/winextras/qwinmime.h
@@ -0,0 +1,78 @@
+/****************************************************************************
+**
+** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the QtWinExtras module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** 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 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, 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.
+**
+** 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.
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QWINMIME_H
+#define QWINMIME_H
+
+#include <QtWinExtras/qwinextrasglobal.h>
+
+#include <QtCore/qt_windows.h>
+#include <QtCore/QVector>
+#include <QtCore/QList>
+#include <QtCore/QVariant>
+
+QT_BEGIN_NAMESPACE
+
+class QMimeData;
+
+class Q_WINEXTRAS_EXPORT QWinMime // Keep in sync with QWindowsMime in the Windows platform plugin.
+{
+    Q_DISABLE_COPY(QWinMime)
+public:
+    QWinMime();
+    virtual ~QWinMime();
+
+    // for converting from Qt
+    virtual bool canConvertFromMime(const FORMATETC &formatetc, const QMimeData *mimeData) const = 0;
+    virtual bool convertFromMime(const FORMATETC &formatetc, const QMimeData *mimeData, STGMEDIUM * pmedium) const = 0;
+    virtual QVector<FORMATETC> formatsForMime(const QString &mimeType, const QMimeData *mimeData) const = 0;
+
+    // for converting to Qt
+    virtual bool canConvertToMime(const QString &mimeType, IDataObject *pDataObj) const = 0;
+    virtual QVariant convertToMime(const QString &mimeType, IDataObject *pDataObj, QVariant::Type preferredType) const = 0;
+    virtual QString mimeForFormat(const FORMATETC &formatetc) const = 0;
+
+    static int registerMimeType(const QString &mime);
+};
+
+QT_END_NAMESPACE
+
+#endif // QWINMIME_H
diff --git a/src/winextras/winextras.pro b/src/winextras/winextras.pro
index 4537f94..7f6bba4 100644
--- a/src/winextras/winextras.pro
+++ b/src/winextras/winextras.pro
@@ -2,6 +2,8 @@ TARGET = QtWinExtras
 
 load(qt_module)
 
+QT += gui-private core-private
+
 SOURCES += \
     qwinfunctions.cpp \
     qwinfunctions_p.cpp \
@@ -14,7 +16,8 @@ SOURCES += \
     qwineventfilter.cpp \
     qwinthumbnailtoolbar.cpp \
     qwinthumbnailtoolbutton.cpp \
-    qwinevent.cpp
+    qwinevent.cpp \
+    qwinmime.cpp
 
 HEADERS += \
     qwinfunctions.h \
@@ -37,7 +40,8 @@ HEADERS += \
     qwinthumbnailtoolbutton.h \
     qwinthumbnailtoolbutton_p.h \
     qwinevent.h \
-    windowsguidsdefs_p.h
+    windowsguidsdefs_p.h \
+    qwinmime.h
 
 QMAKE_DOCS = $$PWD/doc/qtwinextras.qdocconf