lumiera_/src/include/session-command-facade.h

138 lines
5.4 KiB
C++

/*
SESSION-COMMAND-FACADE.h - access point for invoking commands on the session
Copyright (C) Lumiera.org
2016, 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 session-command-facade.h
** Major public Interface to the Session subsystem of Lumiera GUI.
** This interface describes the ability of the Session to trigger the execution
** of pre-defined commands, outfitted with suitable arguments and parameters.
** Triggering of these commands typically happens in response to some messages
** being sent over the UI-Bus. Likewise, external entities (e.g. plug-ins) may
** invoke commands over this interface to alter the session.
**
** For this reason, the operations exposed here are defined in terms matching
** the structure of binding and invocation messages. This goes so far as to
** accept the command arguments for binding packaged as `Record<GenNode>`.
** For each command, there needs to be a registration record within the
** Steam-Layer implementation. The service implementation backing this
** facade indeed retrieves the corresponding proc::control::Command
** handles to perform the binding operation and hands them over
** to the ProcDispatcher for invocation.
**
** @see command.hpp
** @see session-command-service.hpp implementation
** @see proc::control::ProcDispatcher
** @see gui::ctrl::CoreService
*/
#ifndef PROC_CONTROL_SESSION_COMMAND_H
#define PROC_CONTROL_SESSION_COMMAND_H
#ifdef __cplusplus /* ============== C++ Interface ================= */
#include "lib/depend.hpp"
#include "lib/diff/gen-node.hpp"
#include "lib/symbol.hpp"
#include <string>
namespace proc {
namespace control {
using lib::Symbol;
using std::string;
/**********************************************************************//**
* Global access point to invoke commands and cause edit operations within
* the Session. Any changes to the session are effected by prepared functors
* bound into a proc::control::Command registration. A command instance will
* first be outfitted with suitable parameters to define the target and to
* qualify and elaborate the action, before it can be actually triggered.
* Commands then go through a queue to be invoked one by one.
*
* The service exposed through this facade offers dedicated support for
* the _standard command cycle_, as is typically performed from the UI.
* Such a usage cycle starts with ["opening"](\ref #cycle) a local anonymous
* clone copy from the global command definition, which is then used
* in further calls to be outfitted with actual arguments and finally
* to be handed over to the dispatcher for execution.
* @warning this standard command cycle is intended for single-threaded
* use from the UI. It is not threadsafe. To the contrary, all
* operations with globally registered commands are threadsafe.
*
* @remark This is a layer separation facade interface. Clients should
* use the embedded #facade factory, which yields a proxy to route any
* calls through the lumieraorg_SessionCommand interface
* @throws lumiera::error::State when interface is not opened
* @see [Command system](\ref command.hpp)
* @see SessionCommandFunction_test
*/
class SessionCommand
{
public:
static lib::Depend<SessionCommand> facade;
/** start next command cycle and "open" a new anonymous command instance */
virtual Symbol cycle (Symbol cmdID, string const& invocationID) =0;
/** bind the command's arguments and trigger command invocation immediately */
virtual void trigger (Symbol cmdID, lib::diff::Rec const& args) =0;
/** prepare command invocation: bind the command's arguments */
virtual void bindArg (Symbol cmdID, lib::diff::Rec const& args) =0;
/** trigger invocation of a prepared command */
virtual void invoke (Symbol cmdID) =0;
protected:
virtual ~SessionCommand() {} ///< this is an interface
friend class lib::DependencyFactory<SessionCommand>;
};
}} // namespace proc::control
extern "C" {
#endif /* =========================== CL Interface ===================== */
#include "common/interface.h"
LUMIERA_INTERFACE_DECLARE (lumieraorg_SessionCommand, 0,
LUMIERA_INTERFACE_SLOT (const char*, cycle, (const char*, const char*)),
LUMIERA_INTERFACE_SLOT (void, trigger, (const char*, const void*)),
LUMIERA_INTERFACE_SLOT (void, bindArg, (const char*, const void*)),
LUMIERA_INTERFACE_SLOT (void, invoke, (const char*)),
);
#ifdef __cplusplus
}// extern "C"
#endif
#endif /*PROC_CONTROL_SESSION_COMMAND_H*/