Cocoa: Support pasting rich text to Qt apps

Native Mac OS X apps uses Rtf as the rich text format
while Qt uses html. Add QMacPasteboardMimeRtfText
which supports converting from public.rtf to text/html
(but not the other way around, since we want to keep
posting our html as html).

The QMacInternalPasteboardMime API does not support
the concept of a one-way handler. Skip the Rtf handler
in QMacPasteboard::setMimeData().

Task-number: QTBUG-37188
Change-Id: Ibe29997a038bbb64da24b961e84a5f60133074e0
Reviewed-by: Gabriel de Dietrich <gabriel.dedietrich@digia.com>

src/plugins/platforms/cocoa/qcocoamimetypes.mm

@@ -136,9 +136,76 @@ QList<QByteArray> QMacPasteboardMimeTiff::convertFromMime(const QString &mime, Q
     return ret;
 }
 
+// This handler is special: It supports converting public.rtf top text/html,
+// but not the other way around.
+class QMacPasteboardMimeRtfText : public QMacInternalPasteboardMime {
+public:
+    QMacPasteboardMimeRtfText() : QMacInternalPasteboardMime(MIME_ALL) { }
+    QString convertorName();
+
+    QString flavorFor(const QString &mime);
+    QString mimeFor(QString flav);
+    bool canConvert(const QString &mime, QString flav);
+    QVariant convertToMime(const QString &mime, QList<QByteArray> data, QString flav);
+    QList<QByteArray> convertFromMime(const QString &mime, QVariant data, QString flav);
+};
+
+QString QMacPasteboardMimeRtfText::convertorName()
+{
+    return QLatin1String("Rtf");
+}
+
+QString QMacPasteboardMimeRtfText::flavorFor(const QString &mime)
+{
+    if (mime == QLatin1String("text/html"))
+        return QLatin1String("public.rtf");
+    return QString();
+}
+
+QString QMacPasteboardMimeRtfText::mimeFor(QString flav)
+{
+    if (flav == QLatin1String("public.rtf"))
+        return QLatin1String("text/html");
+    return QString();
+}
+
+bool QMacPasteboardMimeRtfText::canConvert(const QString &mime, QString flav)
+{
+    return flavorFor(mime) == flav;
+}
+
+QVariant QMacPasteboardMimeRtfText::convertToMime(const QString &mimeType, QList<QByteArray> data, QString flavor)
+{
+    if (!canConvert(mimeType, flavor))
+        return QVariant();
+    if (data.count() > 1)
+        qWarning("QMacPasteboardMimeHTMLText: Cannot handle multiple member data");
+
+    // Convert Rtf to Html.
+    NSAttributedString *string = [[NSAttributedString alloc] initWithRTF:data.at(0).toNSData() documentAttributes:NULL];
+    NSError *error;
+    NSRange range = NSMakeRange(0,[string length]);
+    NSDictionary *dict = [NSDictionary dictionaryWithObject:NSHTMLTextDocumentType forKey:NSDocumentTypeDocumentAttribute];
+    NSData *htmldata = [string dataFromRange:range documentAttributes:dict error:&error];
+    [string release];
+    return QByteArray::fromNSData(htmldata);
+}
+
+QList<QByteArray> QMacPasteboardMimeRtfText::convertFromMime(const QString &mime, QVariant data, QString flavor)
+{
+    Q_UNUSED(mime);
+    Q_UNUSED(data);
+    Q_UNUSED(flavor);
+
+    qWarning("QMacPasteboardMimeRtfText: Conversion from Html to Rtf is not supported");
+    QList<QByteArray> ret;
+    return ret;
+}
+
 void QCocoaMimeTypes::initializeMimeTypes()
 {
     new QMacPasteboardMimeTiff;
+    new QMacPasteboardMimeRtfText;
 }
 
 QT_END_NAMESPACE

src/plugins/platforms/cocoa/qmacclipboard.mm

@@ -305,6 +305,11 @@ QMacPasteboard::setMimeData(QMimeData *mime_src)
             QString mimeType = formats.at(f);
             for (QList<QMacInternalPasteboardMime *>::Iterator it = availableConverters.begin(); it != availableConverters.end(); ++it) {
                 QMacInternalPasteboardMime *c = (*it);
+                // Hack: The Rtf handler converts incoming Rtf to Html. We do
+                // not want to convert outgoing Html to Rtf but instead keep
+                // posting it as Html. Skip the Rtf handler here.
+                if (c->convertorName() == QStringLiteral("Rtf"))
+                    continue;
                 QString flavor(c->flavorFor(mimeType));
                 if (!flavor.isEmpty()) {
                     QVariant mimeData = static_cast<QMacMimeData*>(mime_src)->variantData(mimeType);