LUMIERA.clone/src/include/lifecycle.h

102 lines
3.5 KiB
C++

/*
LIFECYCLE.h - interface for registering and triggering lifecycle callbacks
Copyright (C) Lumiera.org
2008, 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 lifecycle.h
** Interface for registering and triggering application lifecycle event callbacks.
** This service is a facade for and implemented by lumiera::AppState.
** By placing a static LifecycleHook variable or by calling LifecycleHook::add,
** a callback can be registered to be executed on a specific application lifecycle
** event. Examples being #ON_BASIC_INIT, #ON_GLOBAL_INIT. Other subsystems may
** register additional events for more specific purpose.
**
** @see lumiera::AppState
** @see main.cpp
*/
#ifndef LUMIERA_LIFECYCLE_H
#define LUMIERA_LIFECYCLE_H
#ifdef __cplusplus
#include "include/symbol.hpp"
#include <boost/noncopyable.hpp>
namespace lumiera {
extern Symbol ON_BASIC_INIT; ///< automatic static init. treated specially
extern Symbol ON_GLOBAL_INIT; ///< to be triggered in main() @note no magic!
extern Symbol ON_GLOBAL_SHUTDOWN; ///< to be triggered at the end of main() @note no magic!
// client code is free to register and use additional lifecycle events
/**
* define and register a callback for a specific lifecycle event.
* The purpose of this class is to be defined as a static variable in the implementation
* of some subsystem (i.e. in the cpp file), providing the ctor with the pointer to a
* callback function. Thus the callback gets enrolled when the corresponding object file
* is loaded. The event ON_BASIC_INIT is handled specifically, firing off the referred
* callback function as soon as possible. All other labels are just arbitrary (string)
* constants and it is necessary that "someone" cares to fire off the lifecycle events
* at the right place. For example, lumiera-main (and the test runner) calls
* \c AppState::instance().execute(ON_GLOBAL_INIT) (and..SHUTDOWN)
* @note duplicate or repeated calls with the same callback are NOP
*/
class LifecycleHook
: private boost::noncopyable
{
public:
typedef void (*Hook)(void);
LifecycleHook (Symbol eventLabel, Hook callbackFun);
/** alternative, static interface for registering a callback */
static void add (Symbol eventLabel, Hook callbackFun);
/** trigger lifecycle callbacks registered under the given label */
static void trigger (Symbol eventLabel);
};
} // namespace lumiera
#else /* =========== C interface ====================== */
extern const char * lumiera_ON_BASIC_INIT;
extern const char * lumiera_ON_GLOBAL_INIT;
extern const char * lumiera_ON_GLOBAL_SHUTDOWN;
void lumiera_LifecycleHook_add (const char* eventLabel, void callbackFun(void));
void lumiera_Lifecycle_trigger (const char* eventLabel);
#endif
#endif