/* qeventloopinteractor.cpp
   Copyright (C) 2003 Klarälvdalens Datakonsult AB

   This file is part of QGPGME.

   QGPGME is free software; you can redistribute it and/or modify it
   under the terms of the GNU Library General Public License as published
   by the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

   QGPGME is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU Library General Public License for more details.

   You should have received a copy of the GNU Library General Public License
   along with QGPGME; see the file COPYING.LIB.  If not, write to the
   Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
   Boston, MA 02110-1301, USA. */

// -*- c++ -*-

#include <qgpgme/eventloopinteractor.h>

#include <gpgme++/global.h>

#include <QIODevice>
#include <QSignalMapper>

Q_GLOBAL_STATIC( QSignalMapper, readSignalMapper )
Q_GLOBAL_STATIC( QSignalMapper, writeSignalMapper )

static QSignalMapper * setupReadSignalMapper( QObject * o ) {
    QSignalMapper * sm = readSignalMapper();
    o->connect( sm, SIGNAL(mapped(int)), SLOT(slotReadActivity(int)) );
    return sm;
}

static QSignalMapper * setupWriteSignalMapper( QObject * o ) {
    QSignalMapper * sm = writeSignalMapper();
    o->connect( sm, SIGNAL(mapped(int)), SLOT(slotWriteActivity(int)) );
    return sm;
}

namespace {
    struct IO {
        QIODevice * device;
        QGpgME::EventLoopInteractor::Direction direction;
    };
}

void * QGpgME::EventLoopInteractor::registerWatcher( int fd, Direction dir, bool & ok ) {
    QIODevice * const iod = GpgME::getQIODevice( fd );
    if ( !iod ) {
        ok = false;
        return 0;
    }
    if ( dir == Read ) {
        static QSignalMapper * rsm = setupReadSignalMapper( this );
        if ( !rsm->mapping( fd ) ) {
            rsm->setMapping( iod, fd );
            connect( iod, SIGNAL(readyRead()), rsm, SLOT(map()) );
        } else {
            // if this fd is already registered, gpgme registers an additional
            // callback for the same fd.
            // if there is already something to read when registering the new 
            // callback, gpgme expects the new callback to be called, so we
            // trigger it"
            QMetaObject::invokeMethod( this, "slotReadActivity", Qt::QueuedConnection, Q_ARG( int, fd ) );
        }
    } else {
        static QSignalMapper * wsm = setupWriteSignalMapper( this );
        if ( !wsm->mapping( fd ) ) {
            wsm->setMapping( iod, fd );
            connect( iod, SIGNAL(bytesWritten(qint64)), wsm, SLOT(map()) );
        } else {
            // if this fd is already registered, gpgme registers an additional 
            // callback for the same fd.
            // if the device is writable when registering the new 
            // callback, gpgme expects the new callback to be called, so we
            // trigger it:
            QMetaObject::invokeMethod( this, "slotWriteActivity", Qt::QueuedConnection, Q_ARG( int, fd ) );
        }
    }

    ok = true;
    IO * const io = new IO;
    io->device = iod;
    io->direction = dir;
    iod->bytesAvailable(); //HACK: tell KDPipeIODevices to start their threads
    iod->bytesToWrite();
    return io;
}

void QGpgME::EventLoopInteractor::unregisterWatcher( void * tag ) {
    if ( !tag ) {
        return;
    }
    const IO * const io = static_cast<IO*>( tag );
    if ( io->direction == Read ) {
        // no setupReadSignalMapper here, since registerWatcher,
        // called before us, is guaranteed to have set it up
        static QSignalMapper * rsm = readSignalMapper();
        disconnect( io->device, SIGNAL(readyRead()), rsm, SLOT(map()) );
    } else {
        static QSignalMapper * wsm = writeSignalMapper();
        disconnect( io->device, SIGNAL(bytesWritten(qint64)), wsm, SLOT(map()) );
    }
    delete io;
}