Improving clipboard integration

Derive a data accessor class from QMimeData so application level code can
query MIME type availability through it or directly attempt to fetch
data by MIME type even if the type is not yet known to QBBClipboard.

Also make sure any MIME type used by the application in setMimeData
operations is checked for availability when being queried for formats.

Change-Id: If8174adf3f3383496a354d291ef7d36b9732be1d
Reviewed-by: Jørgen Lind <jorgen.lind@nokia.com>

2 files changed, 150 insertions, 39 deletions

diff --git a/src/plugins/platforms/blackberry/qbbclipboard.cpp b/src/plugins/platforms/blackberry/qbbclipboard.cpp
index fce016d5ee..293a0c771b 100644
--- a/src/plugins/platforms/blackberry/qbbclipboard.cpp
+++ b/src/plugins/platforms/blackberry/qbbclipboard.cpp
@@ -46,6 +46,7 @@
 #include <QtGui/QColor>
 
 #include <QtCore/QDebug>
+#include <QtCore/QMimeData>
 #include <QtCore/QStringList>
 #include <QtCore/QUrl>
 
@@ -53,11 +54,131 @@
 #include <errno.h>
 
 QT_BEGIN_NAMESPACE
-static const char *typeList[] = {"text/html", "text/plain", "application/x-color"};
+
+// null terminated array
+static const char *typeList[] = {"text/html", "text/plain", "image/png", "image/jpeg", "application/x-color", 0};
+
+static QByteArray readClipboardBuff(const char *type)
+{
+    char *pbuffer;
+    if (is_clipboard_format_present(type) == 0) {
+        int size = get_clipboard_data(type, &pbuffer);
+        if (size != -1 && pbuffer) {
+            const QByteArray result = QByteArray(pbuffer, size);
+            free(pbuffer);
+            return result;
+        }
+    }
+
+    return QByteArray();
+}
+
+class QBBClipboard::MimeData : public QMimeData
+{
+    Q_OBJECT
+public:
+    MimeData(QBBClipboard *clipboard)
+        : QMimeData(),
+          m_clipboard(clipboard),
+          m_userMimeData(0)
+    {
+        Q_ASSERT(clipboard);
+
+        for (int i = 0; typeList[i] != 0; ++i) {
+            m_formatsToCheck << QString::fromUtf8(typeList[i]);
+        }
+    }
+
+    ~MimeData()
+    {
+        delete m_userMimeData;
+    }
+
+    void addFormatToCheck(const QString &format) {
+        m_formatsToCheck << format;
+
+#if defined(QBBCLIPBOARD_DEBUG)
+        qDebug() << Q_FUNC_INFO << "formats=" << m_formatsToCheck;
+#endif
+    }
+
+    bool hasFormat(const QString &mimetype) const
+    {
+        const bool result = is_clipboard_format_present(mimetype.toUtf8().constData()) == 0;
+#if defined(QBBCLIPBOARD_DEBUG)
+        qDebug() << Q_FUNC_INFO << "mimetype=" << mimetype << "result=" << result;
+#endif
+        return result;
+    }
+
+    QStringList formats() const
+    {
+        QStringList result;
+
+        Q_FOREACH (const QString &format, m_formatsToCheck) {
+            if (is_clipboard_format_present(format.toUtf8().constData()) == 0)
+                result << format;
+        }
+
+#if defined(QBBCLIPBOARD_DEBUG)
+        qDebug() << Q_FUNC_INFO << "result=" << result;
+#endif
+        return result;
+    }
+
+    void setUserMimeData(QMimeData *userMimeData)
+    {
+        delete m_userMimeData;
+        m_userMimeData = userMimeData;
+
+        // system clipboard API doesn't allow detection of changes by other applications
+        // simulate an owner change through delayed invocation
+        // basically transfer ownership of data to the system clipboard once event processing resumes
+        if (m_userMimeData)
+            QMetaObject::invokeMethod(this, "releaseOwnership", Qt::QueuedConnection);
+    }
+
+    QMimeData *userMimeData()
+    {
+        return m_userMimeData;
+    }
+
+protected:
+    QVariant retrieveData(const QString &mimetype, QVariant::Type preferredType) const
+    {
+#if defined(QBBCLIPBOARD_DEBUG)
+        qDebug() << Q_FUNC_INFO << "mimetype=" << mimetype << "preferredType=" << preferredType;
+#endif
+        if (is_clipboard_format_present(mimetype.toUtf8().constData()) != 0)
+            return QMimeData::retrieveData(mimetype, preferredType);
+
+        const QByteArray data = readClipboardBuff(mimetype.toUtf8().constData());
+        return qVariantFromValue(data);
+    }
+
+private Q_SLOTS:
+    void releaseOwnership()
+    {
+        if (m_userMimeData) {
+#if defined(QBBCLIPBOARD_DEBUG)
+            qDebug() << Q_FUNC_INFO << "user data formats=" << m_userMimeData->formats() << "system formats=" << formats();
+#endif
+            delete m_userMimeData;
+            m_userMimeData = 0;
+            m_clipboard->emitChanged(QClipboard::Clipboard);
+        }
+    }
+
+private:
+    QBBClipboard * const m_clipboard;
+
+    QSet<QString> m_formatsToCheck;
+    QMimeData *m_userMimeData;
+};
 
 QBBClipboard::QBBClipboard()
+    : m_mimeData(new MimeData(this))
 {
-    m_mimeData = 0;
 }
 
 QBBClipboard::~QBBClipboard()
@@ -70,46 +191,37 @@ void QBBClipboard::setMimeData(QMimeData *data, QClipboard::Mode mode)
     if (mode != QClipboard::Clipboard)
         return;
 
-    if (m_mimeData != data) {
-        delete m_mimeData;
-        m_mimeData = data;
-    }
+    if (data == m_mimeData || data == m_mimeData->userMimeData())
+        return;
 
     empty_clipboard();
 
+    m_mimeData->clear();
+    m_mimeData->setUserMimeData(data);
+
     if (data == 0)
         return;
 
-    QStringList format = data->formats();
-    for (int i = 0; i < format.size(); ++i) {
-        QString type = format.at(i);
-        QByteArray buf = data->data(type);
-        if (!buf.size())
-            continue;
-
-        int ret = set_clipboard_data(type.toUtf8().data(), buf.size(), buf.data());
+    const QStringList formats = data->formats();
 #if defined(QBBCLIPBOARD_DEBUG)
-        qDebug() << "QBB: set " << type.toUtf8().data() << "to clipboard, size=" << buf.size() << ";ret=" << ret;
-#else
-        Q_UNUSED(ret);
+    qDebug() << Q_FUNC_INFO << "formats=" << formats;
 #endif
-    }
-}
 
-void QBBClipboard::readClipboardBuff(const char *type)
-{
-    char *pbuffer;
-    if (is_clipboard_format_present(type) == 0) {
-        int size = get_clipboard_data(type, &pbuffer);
-        if (size != -1 && pbuffer) {
-            QString qtype = type;
+    Q_FOREACH (const QString &format, formats) {
+        const QByteArray buf = data->data(format);
+
+        if (buf.isEmpty())
+            continue;
+
+        int ret = set_clipboard_data(format.toUtf8().data(), buf.size(), buf.data());
 #if defined(QBBCLIPBOARD_DEBUG)
-            qDebug() << "QBB: clipboard has " << qtype;
+        qDebug() << "QBB: set " << format << "to clipboard, size=" << buf.size() << ";ret=" << ret;
 #endif
-            m_mimeData->setData(qtype, QByteArray(pbuffer, size));
-            delete pbuffer;
-        }
+        if (ret)
+            m_mimeData->addFormatToCheck(format);
     }
+
+    emitChanged(QClipboard::Clipboard);
 }
 
 QMimeData *QBBClipboard::mimeData(QClipboard::Mode mode)
@@ -117,16 +229,16 @@ QMimeData *QBBClipboard::mimeData(QClipboard::Mode mode)
     if (mode != QClipboard::Clipboard)
         return 0;
 
-    if (!m_mimeData)
-        m_mimeData = new QMimeData();
+    if (m_mimeData->userMimeData())
+        return m_mimeData->userMimeData();
 
     m_mimeData->clear();
 
-    for (int i = 0; i < 3; i++)
-        readClipboardBuff(typeList[i]);
-
     return m_mimeData;
 }
 
 QT_END_NAMESPACE
-#endif //QT_NO_CLIPBOAR
+
+#include "qbbclipboard.moc"
+
+#endif //QT_NO_CLIPBOARD
diff --git a/src/plugins/platforms/blackberry/qbbclipboard.h b/src/plugins/platforms/blackberry/qbbclipboard.h
index b9de9b3e36..11a36ba8e5 100644
--- a/src/plugins/platforms/blackberry/qbbclipboard.h
+++ b/src/plugins/platforms/blackberry/qbbclipboard.h
@@ -44,7 +44,6 @@
 
 #ifndef QT_NO_CLIPBOARD
 #include <QtGui/QPlatformClipboard>
-#include <QMimeData>
 
 QT_BEGIN_NAMESPACE
 
@@ -57,8 +56,8 @@ public:
     virtual void setMimeData(QMimeData *data, QClipboard::Mode mode = QClipboard::Clipboard);
 
 private:
-    QMimeData *m_mimeData;
-    void readClipboardBuff(const char *type);
+    class MimeData;
+    MimeData *m_mimeData;
 };
 
 QT_END_NAMESPACE