kdelibs/kdeui/util/kxmessages.cpp

/****************************************************************************

 Copyright (C) 2001-2003 Lubos Lunak        <l.lunak@kde.org>

Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and associated documentation files (the "Software"),
to deal in the Software without restriction, including without limitation
the rights to use, copy, modify, merge, publish, distribute, sublicense,
and/or sell copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
DEALINGS IN THE SOFTWARE.

****************************************************************************/

#include "kxmessages.h"
#include "kdebug.h"

#include <qx11info_x11.h>
#include <X11/Xlib.h>
#include <fixx11h.h>
#include "kapplication.h"

static QByteArray makeMessageAtomName(const char* const msg_type_P)
{
    QByteArray result(msg_type_P);
    if (Q_UNLIKELY(result.endsWith("_BEGIN"))) {
        kWarning() << "Message" << msg_type_P << "should not end with _BEGIN";
        return result;
    }
    result.append("_BEGIN");
    return result;
}

class KXMessagesPrivate
{
public:
    QWidget* handle;
    Atom accept_atom2;
    Atom accept_atom1;
    QMap<WId, QByteArray> incoming_messages;
};


// for broadcasting
const long BROADCAST_MASK = PropertyChangeMask;
// CHECKME

KXMessages::KXMessages(const char* accept_broadcast_P, QWidget* parent_P)
    : QWidget(parent_P)
    , d(new KXMessagesPrivate())
{
    if (accept_broadcast_P != NULL) {
        (void)qApp->desktop(); //trigger desktop widget creation to select root window events
        kapp->installX11EventFilter(this); // i.e. PropertyChangeMask
        d->accept_atom2 = XInternAtom(QX11Info::display(), accept_broadcast_P, false);
        const QByteArray a1name = makeMessageAtomName(accept_broadcast_P);
        d->accept_atom1 = XInternAtom( QX11Info::display(), a1name.constData(), false);
    } else {
        d->accept_atom1 = d->accept_atom2 = None;
    }
    d->handle = new QWidget(this);
}

KXMessages::~KXMessages()
{
    delete d;
}

void KXMessages::broadcastMessage(const char* msg_type_P, const QString& message_P, int screen_P)
{
    Atom a2 = XInternAtom( QX11Info::display(), msg_type_P, false);
    const QByteArray a1name = makeMessageAtomName(msg_type_P);
    Atom a1 = XInternAtom(QX11Info::display(), a1name.constData(), false);
    Window root = screen_P == -1 ? QX11Info::appRootWindow() : QX11Info::appRootWindow( screen_P );

    send_message_internal(root, message_P, BROADCAST_MASK, QX11Info::display(), a1, a2, d->handle->winId());
}

void KXMessages::sendMessage(WId w_P, const char* msg_type_P, const QString& message_P)
{
    Atom a2 = XInternAtom(QX11Info::display(), msg_type_P, false);
    const QByteArray a1name = makeMessageAtomName(msg_type_P);
    Atom a1 = XInternAtom(QX11Info::display(), a1name.constData(), false);

    send_message_internal(w_P, message_P, 0, QX11Info::display(), a1, a2, d->handle->winId());
}

bool KXMessages::broadcastMessageX(Display* disp, const char* msg_type_P, const QString& message_P, int screen_P)
{
    if (disp == NULL) {
        return false;
    }

    Atom a2 = XInternAtom(disp, msg_type_P, false);
    const QByteArray a1name = makeMessageAtomName(msg_type_P);
    Atom a1 = XInternAtom(disp, a1name.constData(), false);
    Window root = screen_P == -1 ? DefaultRootWindow(disp) : RootWindow(disp, screen_P);
    Window win = XCreateSimpleWindow(
        disp, root, 0, 0, 1, 1,
        0, BlackPixel(disp, screen_P == -1 ? DefaultScreen(disp) : screen_P),
        BlackPixel(disp, screen_P == -1 ? DefaultScreen( disp ) : screen_P)
    );
    send_message_internal(root, message_P, BROADCAST_MASK, disp, a1, a2, win);
    XDestroyWindow(disp, win);

    return true;
}

bool KXMessages::sendMessageX(Display* disp, WId w_P, const char* msg_type_P, const QString& message_P)
{
    if (disp == NULL) {
        return false;
    }

    Atom a2 = XInternAtom(disp, msg_type_P, false);
    const QByteArray a1name = makeMessageAtomName(msg_type_P);
    Atom a1 = XInternAtom(disp, a1name.constData(), false);
    Window win = XCreateSimpleWindow(
        disp, DefaultRootWindow(disp), 0, 0, 1, 1,
        0, BlackPixelOfScreen( DefaultScreenOfDisplay(disp)),
        BlackPixelOfScreen(DefaultScreenOfDisplay(disp))
    );
    send_message_internal(w_P, message_P, 0, disp, a1, a2, win);
    XDestroyWindow(disp, win);

    return true;
}

void KXMessages::send_message_internal(WId w_P, const QString& msg_P, long mask_P,
                                       Display* disp, Atom atom1_P, Atom atom2_P, Window handle_P)
{
    unsigned int pos = 0;
    QByteArray msg = msg_P.toUtf8();
    unsigned int len = strlen(msg);

    XEvent e;
    e.xclient.type = ClientMessage;
    e.xclient.message_type = atom1_P; // leading message
    e.xclient.display = disp;
    e.xclient.window = handle_P;
    e.xclient.format = 8;
    do {
        unsigned int i;
        for(i = 0; i < 20 && i + pos <= len; ++i) {
            e.xclient.data.b[i] = msg[i + pos];
        }
        XSendEvent( disp, w_P, false, mask_P, &e);
        e.xclient.message_type = atom2_P; // following messages
        pos += i;
    } while(pos <= len);

    XFlush(disp);
}

bool KXMessages::x11Event( XEvent* ev_P )
{
    if (ev_P->type != ClientMessage || ev_P->xclient.format != 8) {
        return QWidget::x11Event(ev_P);
    }
    if (ev_P->xclient.message_type != d->accept_atom1 && ev_P->xclient.message_type != d->accept_atom2) {
        return QWidget::x11Event(ev_P);
    }

    char buf[21]; // can't be longer
    int i;
    for (i = 0; i < 20 && ev_P->xclient.data.b[i] != '\0'; ++i) {
        buf[i] = ev_P->xclient.data.b[i];
    }
    buf[i] = '\0';

    if (d->incoming_messages.contains(ev_P->xclient.window)) {
        if (ev_P->xclient.message_type == d->accept_atom1 && d->accept_atom1 != d->accept_atom2) {
            // two different messages on the same window at the same time shouldn't happen anyway
            d->incoming_messages[ev_P->xclient.window] = QByteArray();
        }
        d->incoming_messages[ev_P->xclient.window] += buf;
    } else {
        if (ev_P->xclient.message_type == d->accept_atom2 && d->accept_atom1 != d->accept_atom2) {
            // middle of message, but we don't have the beginning
            return false;
        }
        d->incoming_messages[ev_P->xclient.window] = buf;
    }

    if (i < 20) {
        // last message fragment
        emit gotMessage(QString::fromUtf8(d->incoming_messages[ev_P->xclient.window]));
        d->incoming_messages.remove(ev_P->xclient.window);
    }

    // lets other KXMessages instances get the event too
    return false;
}

#include "moc_kxmessages.cpp"