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+/*
+ eventloopinteractor.h
+ Copyright (C) 2003,2004 Klarälvdalens Datakonsult AB
+
+ This file is part of GPGME++.
+
+ GPGME++ 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.
+
+ GPGME++ 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 GPGME++; 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++ -*-
+#ifndef __GPGMEPP_EVENTLOOPINTERACTOR_H__
+#define __GPGMEPP_EVENTLOOPINTERACTOR_H__
+
+#include "gpgmepp_export.h"
+
+namespace GpgME
+{
+
+class Context;
+class Error;
+class TrustItem;
+class Key;
+
+/*! \file eventloopinteractor.h
+ \brief Abstract base class for gpgme's external event loop support
+
+ This class does most of the work involved with hooking GpgME++
+ up with external event loops, such as the GTK or Qt ones.
+
+ It actually provides two interfaces: An interface to the gpgme
+ IO Callback handling and one for gpgme events. The IO Callback
+ interface consists of the three methods \c actOn(), \c
+ registerWatcher() and \c unregisterWatcher(). The event
+ interface consists of the three methods \c nextTrustItemEvent(),
+ \c nextKeyEvent() and \c operationDoneEvent().
+
+ \sect General Usage
+
+ \c EventLoopInteractor is designed to be used as a
+ singleton. However, in order to make any use of it, you have to
+ subclass it and reimplement it's pure virtual methods (see
+ below). We suggest you keep the constructor protected and
+ provide a static \c instance() method that returns the single
+ instance. Alternatively, you can create an instance on the
+ stack, e.g. in \c main().
+
+ If you want \c EventLoopInteractor to manage a particular \c
+ Context, just call \c manage() on the \c Context. OTOH, if you
+ want to disable IO callbacks for a \c Context, use \c unmanage().
+
+ \sect IO Callback Interface
+
+ One part of this interface is represented by \c
+ registerWatcher() and \c unregisterWatcher(), both of which are
+ pure virtual. \c registerWatcher() should do anything necessary
+ to hook up watching of file descriptor \c fd for reading (\c dir
+ = \c Read) or writing (\c dir = Write) to the event loop you use
+ and return a tag identifying that particular watching process
+ uniquely. This could be the index into an array of objects you
+ use for that purpose or the address of such an object. E.g. in
+ Qt, you'd essentially just create a new \c QSocketNotifier:
+
+ \verbatim
+ void * registerWatcher( int fd, Direction dir ) {
+ return new QSocketNotifier( fd, dir == Read ? QSocketNotifier::Read : QSocketNotifier::Write );
+ // misses connecting to the activated() signal...
+ }
+ \endverbatim
+
+ which uses the address of the created object as unique tag. The
+ tag returned by \c registerWatcher is stored by \c
+ EventLoopInteractor and passed as argument to \c
+ unregisterWatcher(). So, in the picture above, you'd implement \c
+ unregisterWatcher() like this:
+
+ \verbatim
+ void unregisterWatcher( void * tag ) {
+ delete static_cast<QSocketNotifier*>( tag );
+ }
+ \endverbatim
+
+ The other part of the IO callback interface is \c actOn(), which
+ you should call if you receive notification from your event loop
+ about activity on file descriptor \c fd in direction \c dir. In
+ the picture above, you'd call this from the slot connected to
+ the socket notifier's \c activated() signal.
+
+ \note \c registerWatcher() as well as \c unregisterWatcher() may
+ be called from within \c actOn(), so be careful with
+ e.g. locking in threaded environments and keep in mind that the
+ object you used to find the \c fd and \c dir fo the \c actOn()
+ call might be deleted when \c actOn() returns!
+
+ \sect Event Handler Interface
+
+*/
+class GPGMEPP_EXPORT EventLoopInteractor
+{
+protected:
+ EventLoopInteractor();
+public:
+ virtual ~EventLoopInteractor();
+
+ static EventLoopInteractor *instance()
+ {
+ return mSelf;
+ }
+
+ void manage(Context *context);
+ void unmanage(Context *context);
+
+ enum Direction { Read, Write };
+protected:
+ //
+ // IO Notification Interface
+ //
+
+ /** Call this if your event loop detected activity on file
+ descriptor fd, with direction dir */
+ void actOn(int fd, Direction dir);
+
+ virtual void *registerWatcher(int fd, Direction dir, bool &ok) = 0;
+ virtual void unregisterWatcher(void *tag) = 0;
+
+ //
+ // Event Handler Interface
+ //
+
+ virtual void operationStartEvent(Context *context) = 0;
+ virtual void nextTrustItemEvent(Context *context, const TrustItem &item) = 0;
+ virtual void nextKeyEvent(Context *context, const Key &key) = 0;
+ virtual void operationDoneEvent(Context *context, const Error &e) = 0;
+
+private:
+ class Private;
+ friend class Private;
+ Private *const d;
+ static EventLoopInteractor *mSelf;
+};
+
+}
+
+#endif // __GPGMEPP_EVENTLOOPINTERACTOR_H__