lumiera_/src/gui/ctrl/bus-term.hpp
2015-11-28 23:50:56 +01:00

128 lines
4.1 KiB
C++

/*
BUS-TERM.hpp - connection point for UI elements to the UI-Bus
Copyright (C) Lumiera.org
2015, Hermann Vosseler <Ichthyostega@web.de>
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of
the License, or (at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/** @file bus-term.hpp
** Attachment point to the UI-Bus.
** Every gui::model::Tangible holds a BusTerm, which is linked
** to the Tangible's identity, and serves to relay interface actions
** towards the Proc-Layer, to remember state changes and to broadcast
** notifications. Moreover, the BusTerm is the service point
** to receive structural change messages.
**
** \par Lifecycle and identity
** An BusTerm is always created starting from another BusTerm, to
** which it will be wired. Moreover, each BusTerm bears a distinct
** [identity][::endpointID_], which is used as _implicit subject_
** for emanating messages, or as explicit destination for routing.
** The whole [UI-Bus][BusController] is built to perform within the
** UI event thread and thus is _not threadsafe_. For that reason,
** the automatic detachment built into each BusTerm's dtor is
** sufficient to ensure sane connectivity.
**
** @todo as of 11/2015 this is complete WIP-WIP-WIP
**
** @see ////TODO_test usage example
**
*/
#ifndef GUI_CTRL_BUS_TERM_H
#define GUI_CTRL_BUS_TERM_H
#include "lib/error.hpp"
//#include "lib/symbol.hpp"
//#include "lib/util.hpp"
#include "lib/idi/entry-id.hpp"
#include "lib/diff/gen-node.hpp"
#include <boost/noncopyable.hpp>
#include <utility>
#include <string>
namespace gui {
namespace ctrl{
// using lib::HashVal;
// using util::isnil;
using lib::idi::EntryID;
using lib::diff::GenNode;
using std::string;
/**
* connection point at the UI-Bus.
* The UI-Bus is a star shaped network of terminal points,
* where each \link Tangible tangible UI element \endlink
* holds a BusTerm serving access point. The BusTerm interface
* exposes the basic "verbs" available for communication within
* the UI
* - to _act_ on an element means to issue a command
* - to _note_ some state or information for later replay
* - to _mark_ as erroneous, send an information message,
* replay remembered presentation state or effect structural change
* There are \em indirect variants of the message verbs, which are
* intended for routing, broadcasting or forwarding. Effectively,
* routing is determined from the context and meaning of a message,
* where the _act_ and _note_ messages have an implicit receiver
* (either the Proc-Layer or the UI state manager), while the
* _mark_ messages are always directed _downstream_ towards
* some element.
*/
class BusTerm
{
using ID = lib::idi::BareEntryID;
ID endpointID_;
BusTerm& theBus_;
public:
virtual ~BusTerm(); ///< this is an interface
virtual void act (GenNode command);
virtual void note (GenNode mark);
virtual void mark (GenNode mark);
virtual void note (ID subject, GenNode mark);
virtual void mark (ID subject, GenNode mark);
BusTerm&& attach (ID newAddress);
ID getID() const;
/** may be moved, but not copied,
* due to the embedded identity */
BusTerm(BusTerm&&) = default;
protected:
BusTerm(ID identity, BusTerm& attached_to)
: endpointID_(identity)
, theBus_(attached_to)
{ }
};
}} // namespace gui::ctrl
#endif /*GUI_CTRL_BUS_TERM_H*/