lumiera_/src/gui/ctrl/bus-controller.cpp

/*
  BusController  -  the UI-Bus service

  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-controller.cpp
 ** Implementation of the UI backbone service for messaging.
 ** Any globally relevant widget or controller within the Lumiera UI
 ** is connected to the [UI-Bus][ui-bus.hpp], which is largely implemented
 ** within this compilation unit. [Clients][gui::model::Tangible] typically
 ** use the [BusTerm-Interface][bus-term.hpp] to route generic actions and
 ** receive notifications, state changes and mutations.
 ** 
 ** @note as of 11/2015 this is complete WIP_WIP
 ** @todo WIP  ///////////////////////TICKET #975
 ** 
 ** @see ////TODO_test usage example
 ** @see bus-controller.cpp implementation
 ** 
 */


#include "lib/util.hpp"
//#include "lib/symbol.hpp"
//#include "include/logging.h"
#include "gui/ctrl/bus-term.hpp"
#include "gui/ctrl/bus-controller.hpp"
#include "gui/ctrl/nexus.hpp"

//#include <boost/noncopyable.hpp>
#include <string>
#include <map>

using std::map;
using std::string;

using util::contains;
using util::isnil;


namespace gui {
namespace ctrl { 

  namespace { // internal details
    
  } // internal details
  
  
  // emit VTables here...
  
  /** @note detaches the corresponding node automatically */
  BusTerm::~BusTerm()
  {
    theBus_.routeDetach (this->endpointID_);
  }
  
  
  
  
  /** Builder function: establish and wire a new BusTerm.
   * @param newNode the UI-Element corresponding to and using the new BusTerm
   * @remarks automatically establishes a down-link connection to the given
   *        [Tangible]; the UI-Bus will use this node as target to dispatch
   *        `mark` messages addressed to the new node's ID. It is expected
   *        that the Tangible in turn will use the returned BusTerm for
   *        any up-link communication. Thus, on destruction, the new
   *        BusTerm will detach this UI-Bus connection alltogether.
   */
  BusTerm
  BusTerm::attach (ID identity, Tangible& newNode)
  {
    return BusTerm(identity, theBus_.routeAdd(newNode));
  }
  
  
  
  /* ==== standard implementation of the BusTerm interface ==== */
  
  /** prepare or trigger invocation of a command.
   * @param command a GenNode holding parameters invocation trigger
   * @remarks some commands can simply be invoked right away, but
   *          in the general case, command preparation and invocation
   *          is a multi-step process. The gui::interact::InvocationTrail
   *          is used to conduct this argument binding process from within
   *          the UI. Here, at the UI-Bus interface, we're just interested
   *          in the fact _that_ some command is to be bound or invoked.
   *          This information is forwarded to the command receiver service,
   *          which in turn talks to the proc dispatcher.
   * @note no information regarding the _origin_ of this command invocation
   *          is captured. If a command needs a _subject_, this has to be
   *          bound as an command argument beforehand.
   * @see gui::interact::InvocationTrail
   * @see gui::model::Tangible::prepareCommand()
   * @see gui::model::Tangible::issueCommand()
   */
  void
  BusTerm::act (GenNode const& command)
  {
    theBus_.act (command);
  }
  
  
  /** capture and record a "state mark" for later replay for restoring UI state.
   * @param subject the [endpoint-ID][BusTerm::endpointID_] of the emitting element
   * @param mark the actual state update or notification message to be remembered
   * @remarks relevant changes to presentation state, which are to be recalled and
   *          restored later, are emitted from the place they occur, packaged as
   *          "state mark" messages. This assumes the presence of some dedicated
   *          presentation state manager, attached and listening somewhere at
   *          a core service location. Such a core presentation state service
   *          has shares additional understanding of the state mark's meaning;
   *          it is assumed to track cumulated state, which will be replayed
   *          later when it comes to restoring some presentation state.
   */
  void
  BusTerm::note (ID subject, GenNode const& mark)
  {
    theBus_.note (subject,mark);
  }
  
  
  /** route a state update or notification to the given subject.
   * @param subject the [endpoint-ID][BusTerm::endpointID_] of the element to address
   * @param mark the actual state update or notification message to be delivered
   * @remarks each "subject" to be addressed is a gui::model::Tangible, and as such
   *          holds a BusTerm of its own, which in turn ensures a registration and
   *          connection from the [central routing hub][gui::ctrl::Nexus] down to
   *          the element. Thus, the default implementation is just to pass the
   *          given state mark "up", assuming that it will reach the hub
   *          eventually, which in turn knows hot to reach the element.
   * @note messages to unreachable elements will be dropped silently.
   */
  void
  BusTerm::mark (ID subject, GenNode const& mark)
  {
    theBus_.mark (subject,mark);
  }
  
  
  /**
   * @internal establish new down-link connection form UI-Bus
   * @param node reference to the [Tangible] to be connected.
   * @return corresponding up-link for the initiating node to use
   */
  BusTerm&
  BusTerm::routeAdd (Tangible& node)
  {
    return theBus_.routeAdd(node);
  }
  
  
  /**
   * @internal disable down-link connection
   * @remarks corresponding node is about to go away.
   */
  void
  BusTerm::routeDetach(ID node)  noexcept
  {
    theBus_.routeDetach (node);
  }

  
  
}} // namespace gui::ctrl