vcl/inc/qt5/QtTransferable.hxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */
   2 /*
   3  * This file is part of the LibreOffice project.
   4  *
   5  * This Source Code Form is subject to the terms of the Mozilla Public
   6  * License, v. 2.0. If a copy of the MPL was not distributed with this
   7  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
   8  *
   9  */
  10
  11 #pragma once
  12
  13 #include <cppuhelper/compbase.hxx>
  14 #include <com/sun/star/datatransfer/XTransferable.hpp>
  15
  16 #include <QtCore/QMimeData>
  17 #include <QtCore/QStringList>
  18 #include <QtGui/QClipboard>
  19
  20 /**
  21  * QtTransferable classes are used to read QMimeData via the XTransferable
  22  * interface. All the functionality is already implemented in the QtTransferable.
  23  *
  24  * The specialisations map to the two users, which provide QMimeData: the Clipboard
  25  * and the Drag'n'Drop functionality.
  26  *
  27  * LO itself seem to just accept "text/plain;charset=utf-16", so it relies on the
  28  * backend to convert to this charset, but still offers "text/plain" itself.
  29  *
  30  * It's the "mirror" interface of the QtMimeData, which is defined below.
  31  **/
  32 class QtTransferable : public cppu::WeakImplHelper<css::datatransfer::XTransferable>
  33 {
  34     QtTransferable(const QtTransferable&) = delete;
  35
  36     const QMimeData* m_pMimeData;
  37
  38 protected:
  39     /** Sets new mime data.
  40      *  Since data flavors supported by this class depend on the mime data,
  41      *  results from previous calls to the public methods of this
  42      *  class are no longer valid after setting new mime data using this method.
  43      *
  44      *  Subclasses that set new mime data must ensure that no data race exists
  45      *  on m_pMimeData.
  46      *  (For the current only subclass doing so, QtClipboardTransferable, all access
  47      *  to m_pMimeData happens with the SolarMutex held.)
  48      */
  49     void setMimeData(const QMimeData* pMimeData) { m_pMimeData = pMimeData; }
  50     const QMimeData* mimeData() const { return m_pMimeData; }
  51
  52 public:
  53     QtTransferable(const QMimeData* pMimeData);
  54
  55     css::uno::Sequence<css::datatransfer::DataFlavor> SAL_CALL getTransferDataFlavors() override;
  56     sal_Bool SAL_CALL isDataFlavorSupported(const css::datatransfer::DataFlavor& rFlavor) override;
  57     css::uno::Any SAL_CALL getTransferData(const css::datatransfer::DataFlavor& rFlavor) override;
  58 };
  59
  60 /**
  61  * The QClipboard's QMimeData is volatile. As written in the QClipboard::mimeData
  62  * documentation, "the pointer returned might become invalidated when the contents
  63  * of the clipboard changes". Therefore it can just be accessed reliably inside
  64  * the QClipboard's object thread, which is the QApplication's thread, so all of
  65  * the access has to go through RunInMainThread().
  66  *
  67  * If we detect a QMimeData change, the mime data is updated with the new one from
  68  * the system clipboard. Note however that this means that results of any previous
  69  * calls of the XTransferable interface will be out of sync with the newly set mime
  70  * data, so this scenario should generally be avoided.
  71  **/
  72 class QtClipboardTransferable final : public QtTransferable
  73 {
  74     // to detect in-flight QMimeData changes
  75     const QClipboard::Mode m_aMode;
  76
  77     void ensureConsistencyWithSystemClipboard();
  78
  79 public:
  80     explicit QtClipboardTransferable(const QClipboard::Mode aMode, const QMimeData* pMimeData);
  81
  82     // whether pMimeData are the current mime data
  83     bool hasMimeData(const QMimeData* pMimeData) const;
  84
  85     // these are the same then QtTransferable, except they go through RunInMainThread
  86     css::uno::Sequence<css::datatransfer::DataFlavor> SAL_CALL getTransferDataFlavors() override;
  87     sal_Bool SAL_CALL isDataFlavorSupported(const css::datatransfer::DataFlavor& rFlavor) override;
  88     css::uno::Any SAL_CALL getTransferData(const css::datatransfer::DataFlavor& rFlavor) override;
  89 };
  90
  91 /**
  92  * Convenience typedef for better code readability
  93  *
  94  * This just uses the QMimeData provided by the QWidgets D'n'D events.
  95  **/
  96 typedef QtTransferable QtDnDTransferable;
  97
  98 /**
  99  * A lazy loading QMimeData for XTransferable reads
 100  *
 101  * This is an interface class to make a XTransferable read accessible as a
 102  * QMimeData. The mime data is just stored inside the XTransferable, never
 103  * in the QMimeData itself! It's objects are just used for QClipboard to read
 104  * the XTransferable data.
 105  *
 106  * Like XTransferable itself, this class should be considered an immutable
 107  * container for mime data. There is no need to ever set any of its data.
 108  *
 109  * LO will offer at least UTF-16, if there is a viable text representation.
 110  * If LO misses to offer a UTF-8 or a locale encoded string, these objects
 111  * will offer them themselves and convert from UTF-16 on demand.
 112  *
 113  * It's the "mirror" interface of the QtTransferable.
 114  **/
 115 class QtMimeData final : public QMimeData
 116 {
 117     Q_OBJECT
 118
 119     friend class QtClipboardTransferable;
 120
 121     const css::uno::Reference<css::datatransfer::XTransferable> m_aContents;
 122     mutable bool m_bHaveNoCharset; // = uses the locale charset
 123     mutable bool m_bHaveUTF8;
 124     mutable QStringList m_aMimeTypeList;
 125
 126 #if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
 127     QVariant retrieveData(const QString& mimeType, QVariant::Type type) const override;
 128 #else
 129     QVariant retrieveData(const QString& mimeType, QMetaType type) const override;
 130 #endif
 131
 132 public:
 133     explicit QtMimeData(const css::uno::Reference<css::datatransfer::XTransferable>& aContents);
 134
 135     bool hasFormat(const QString& mimeType) const override;
 136     QStringList formats() const override;
 137
 138     bool deepCopy(QMimeData** const) const;
 139
 140     css::datatransfer::XTransferable* xTransferable() const { return m_aContents.get(); }
 141 };
 142
 143 /* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */