source: trunk/src/corelib/kernel/qmimedata.cpp@ 395

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#include "qmimedata.h"

#include "private/qobject_p.h"
#include "qurl.h"
#include "qstringlist.h"
#include "qtextcodec.h"

QT_BEGIN_NAMESPACE

struct QMimeDataStruct
{
    QString format;
    QVariant data;
};

class QMimeDataPrivate : public QObjectPrivate
{
    Q_DECLARE_PUBLIC(QMimeData)
public:
    void removeData(const QString &format);
    void setData(const QString &format, const QVariant &data);
    QVariant getData(const QString &format) const;

    QVariant retrieveTypedData(const QString &format, QVariant::Type type) const;

    QList<QMimeDataStruct> dataList;
};

void QMimeDataPrivate::removeData(const QString &format)
{
    for (int i=0; i<dataList.size(); i++) {
        if (dataList.at(i).format == format) {
            dataList.removeAt(i);
            return;
        }
    }
}

void QMimeDataPrivate::setData(const QString &format, const QVariant &data)
{
    // remove it first if the format is already here.
    removeData(format);
    QMimeDataStruct mimeData;
    mimeData.format = format;
    mimeData.data = data;
    dataList += mimeData;
}


QVariant QMimeDataPrivate::getData(const QString &format) const
{
    QVariant data;
    for (int i=0; i<dataList.size(); i++) {
        if (dataList.at(i).format == format) {
            data = dataList.at(i).data;
            break;
        }
    }
    return data;
}

QVariant QMimeDataPrivate::retrieveTypedData(const QString &format, QVariant::Type type) const
{
    Q_Q(const QMimeData);

    QVariant data = q->retrieveData(format, type);
    if (data.type() == type || data.type() == QVariant::Invalid)
        return data;

    // provide more conversion possiblities than just what QVariant provides

    // URLs can be lists as well...
    if ((type == QVariant::Url && data.type() == QVariant::List)
        || (type == QVariant::List && data.type() == QVariant::Url))
        return data;

    // images and pixmaps are interchangeable
    if ((type == QVariant::Pixmap && data.type() == QVariant::Image)
        || (type == QVariant::Image && data.type() == QVariant::Pixmap))
        return data;

    if (data.type() == QVariant::ByteArray) {
        // see if we can convert to the requested type
        switch(type) {
#ifndef QT_NO_TEXTCODEC
        case QVariant::String: {
            const QByteArray ba = data.toByteArray();
            QTextCodec *codec = QTextCodec::codecForName("utf-8");
            if (format == QLatin1String("text/html"))
                codec = QTextCodec::codecForHtml(ba, codec);
            return codec->toUnicode(ba);
        }
#endif // QT_NO_TEXTCODEC
        case QVariant::Color: {
            QVariant newData = data;
            newData.convert(QVariant::Color);
            return newData;
        }
        case QVariant::List: {
            if (format != QLatin1String("text/uri-list"))
                break;
            // fall through
        }
        case QVariant::Url: {
            QByteArray ba = data.toByteArray();
            // Qt 3.x will send text/uri-list with a trailing
            // null-terminator (that is *not* sent for any other
            // text/* mime-type), so chop it off
            if (ba.endsWith('\0'))
                ba.chop(1);

            QList<QByteArray> urls = ba.split('\n');
            QList<QVariant> list;
            for (int i = 0; i < urls.size(); ++i) {
                QByteArray ba = urls.at(i).trimmed();
                if (!ba.isEmpty())
                    list.append(QUrl::fromEncoded(ba));
            }
            return list;
        }
        default:
            break;
        }

    } else if (type == QVariant::ByteArray) {

        // try to convert to bytearray
        switch(data.type()) {
        case QVariant::ByteArray:
        case QVariant::Color:
            return data.toByteArray();
            break;
        case QVariant::String:
            return data.toString().toUtf8();
            break;
        case QVariant::Url:
            return data.toUrl().toEncoded();
            break;
        case QVariant::List: {
            // has to be list of URLs
            QByteArray result;
            QList<QVariant> list = data.toList();
            for (int i = 0; i < list.size(); ++i) {
                if (list.at(i).type() == QVariant::Url) {
                    result += list.at(i).toUrl().toEncoded();
                    result += "\r\n";
                }
            }
            if (!result.isEmpty())
                return result;
            break;
        }
        default:
            break;
        }
    }
    return data;
}

/*!
    \class QMimeData
    \brief The QMimeData class provides a container for data that records information
    about its MIME type.

    QMimeData is used to describe information that can be stored in
    the \l{QClipboard}{clipboard}, and transferred via the \l{drag
    and drop} mechanism. QMimeData objects associate the data that
    they hold with the corresponding MIME types to ensure that
    information can be safely transferred between applications, and
    copied around within the same application.

    QMimeData objects are usually created using \c new and supplied
    to QDrag or QClipboard objects. This is to enable Qt to manage
    the memory that they use.

    A single QMimeData object can store the same data using several
    different formats at the same time. The formats() function
    returns a list of the available formats in order of preference.
    The data() function returns the raw data associated with a MIME
    type, and setData() allows you to set the data for a MIME type.

    For the most common MIME types, QMimeData provides convenience
    functions to access the data:

    \table
    \header \o Tester       \o Getter       \o Setter           \o MIME Types
    \row    \o hasText()    \o text()       \o setText()        \o \c text/plain
    \row    \o hasHtml()    \o html()       \o setHtml()        \o \c text/html
    \row    \o hasUrls()    \o urls()       \o setUrls()        \o \c text/uri-list
    \row    \o hasImage()   \o imageData()  \o setImageData()   \o \c image/ *
    \row    \o hasColor()   \o colorData()  \o setColorData()   \o \c application/x-color
    \endtable

    For example, if your write a widget that accepts URL drags, you
    would end up writing code like this:

    \snippet doc/src/snippets/code/src_corelib_kernel_qmimedata.cpp 0

    There are three approaches for storing custom data in a QMimeData
    object:

    \list 1
    \o  Custom data can be stored directly in a QMimeData object as a
        QByteArray using setData(). For example:

        \snippet doc/src/snippets/code/src_corelib_kernel_qmimedata.cpp 1

    \o  We can subclass QMimeData and reimplement hasFormat(),
        formats(), and retrieveData().

    \o  If the drag and drop operation occurs withing a single
        application, we can subclass QMimeData and add extra data in
        it, and use a qobject_cast() in the receiver's drop event
        handler. For example:

        \snippet doc/src/snippets/code/src_corelib_kernel_qmimedata.cpp 2
    \endlist

    \section1 Platform-Specific MIME Types

    On Windows, formats() will also return custom formats available
    in the MIME data, using the \c{x-qt-windows-mime} subtype to
    indicate that they represent data in non-standard formats.
    The formats will take the following form:

    \snippet doc/src/snippets/code/src_corelib_kernel_qmimedata.cpp 3

    The following are examples of custom MIME types:

    \snippet doc/src/snippets/code/src_corelib_kernel_qmimedata.cpp 4

    The \c value declaration of each format describes the way in which the
    data is encoded.

    On Windows, the MIME format does not always map directly to the
    clipboard formats. Qt provides QWindowsMime to map clipboard
    formats to open-standard MIME formats. Similarly, the
    QMacPasteboardMime maps MIME to Mac flavors.

    \sa QClipboard, QDragEnterEvent, QDragMoveEvent, QDropEvent, QDrag,
        QWindowsMime, QMacPasteboardMime, {Drag and Drop}
*/

/*!
    Constructs a new MIME data object with no data in it.
*/
QMimeData::QMimeData()
    : QObject(*new QMimeDataPrivate, 0)
{
}

/*!
    Destroys the MIME data object.
*/
QMimeData::~QMimeData()
{
}

/*!
    Returns a list of URLs contained within the MIME data object.

    URLs correspond to the MIME type \c text/uri-list.

    \sa hasUrls(), data()
*/
QList<QUrl> QMimeData::urls() const
{
    Q_D(const QMimeData);
    QVariant data = d->retrieveTypedData(QLatin1String("text/uri-list"), QVariant::List);
    QList<QUrl> urls;
    if (data.type() == QVariant::Url)
        urls.append(data.toUrl());
    else if (data.type() == QVariant::List) {
        QList<QVariant> list = data.toList();
        for (int i = 0; i < list.size(); ++i) {
            if (list.at(i).type() == QVariant::Url)
                urls.append(list.at(i).toUrl());
        }
    }
    return urls;
}

/*!
    Sets the URLs stored in the MIME data object to those specified by \a urls.

    URLs correspond to the MIME type \c text/uri-list.

    \sa hasUrls(), setData()
*/
void QMimeData::setUrls(const QList<QUrl> &urls)
{
    Q_D(QMimeData);
    QList<QVariant> list;
    for (int i = 0; i < urls.size(); ++i)
        list.append(urls.at(i));

    d->setData(QLatin1String("text/uri-list"), list);
}

/*!
    Returns true if the object can return a list of urls; otherwise
    returns false.

    URLs correspond to the MIME type \c text/uri-list.

    \sa setUrls(), urls(), hasFormat()
*/
bool QMimeData::hasUrls() const
{
    return hasFormat(QLatin1String("text/uri-list"));
}


/*!
    Returns a plain text (MIME type \c text/plain) representation of
    the data.

    \sa hasText(), html(), data()
*/
QString QMimeData::text() const
{
    Q_D(const QMimeData);
    QVariant data = d->retrieveTypedData(QLatin1String("text/plain"), QVariant::String);
    return data.toString();
}

/*!
    Sets \a text as the plain text (MIME type \c text/plain) used to
    represent the data.

    \sa hasText(), setHtml(), setData()
*/
void QMimeData::setText(const QString &text)
{
    Q_D(QMimeData);
    d->setData(QLatin1String("text/plain"), text);
}

/*!
    Returns true if the object can return plain text (MIME type \c
    text/plain); otherwise returns false.

    \sa setText(), text(), hasHtml(), hasFormat()
*/
bool QMimeData::hasText() const
{
    return hasFormat(QLatin1String("text/plain"));
}

/*!
    Returns a string if the data stored in the object is HTML (MIME
    type \c text/html); otherwise returns an empty string.

    \sa hasHtml(), setData()
*/
QString QMimeData::html() const
{
    Q_D(const QMimeData);
    QVariant data = d->retrieveTypedData(QLatin1String("text/html"), QVariant::String);
    return data.toString();
}

/*!
    Sets \a html as the HTML (MIME type \c text/html) used to
    represent the data.

    \sa hasHtml(), setText(), setData()
*/
void QMimeData::setHtml(const QString &html)
{
    Q_D(QMimeData);
    d->setData(QLatin1String("text/html"), html);
}

/*!
    Returns true if the object can return HTML (MIME type \c
    text/html); otherwise returns false.

    \sa setHtml(), html(), hasFormat()
*/
bool QMimeData::hasHtml() const
{
    return hasFormat(QLatin1String("text/html"));
}

/*!
    Returns a QVariant storing a QImage if the object can return an
    image; otherwise returns a null variant.

    A QVariant is used because QMimeData belongs to the \l QtCore
    library, whereas QImage belongs to \l QtGui. To convert the
    QVariant to a QImage, simply use qvariant_cast(). For example:

    \snippet doc/src/snippets/code/src_corelib_kernel_qmimedata.cpp 5

    \sa hasImage()
*/
QVariant QMimeData::imageData() const
{
    Q_D(const QMimeData);