Ichthyostega
685a9b84ee
Benefits - get rid of yet another pervasive Boost dependency - define additional more fine grained policies (move only, clonable)
146 lines
4.4 KiB
C++
146 lines
4.4 KiB
C++
/*
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APPSTATE.hpp - application initialisation and behaviour
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Copyright (C) Lumiera.org
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2008, Hermann Vosseler <Ichthyostega@web.de>
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of
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the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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/** @file appstate.hpp
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** Registering and managing primary application-global services.
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** This can be considered the "main" object of the Lumiera application
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** Besides encapsulating the logic to start up the fundamental parts of
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** the application, there is a mechanism for registering \em subsystems
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** to be brought up and shut down in order. AppState will issue the global
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** application lifecycle events (where other parts may have registered
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** callbacks) and provides the top-level catch-all error handling.
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**
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** @see LifecycleHook
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** @see BasicSetup
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** @see Subsys
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** @see main.cpp
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** @see logging.h
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*/
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#ifndef LUMIERA_APPSTATE_H
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#define LUMIERA_APPSTATE_H
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#include "lib/symbol.hpp"
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#include "lib/nocopy.hpp"
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#include "common/option.hpp"
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#include "common/subsys.hpp"
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#include "common/basic-setup.hpp"
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#include <memory>
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#include <string>
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#include <map>
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namespace lumiera {
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using std::string;
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class SubsystemRunner;
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/**
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* The Lumiera Application state and basic initialisation.
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* Singleton to hold global flags directing the overall application behaviour,
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* for triggering lifecycle events and performing early initialisation tasks.
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* AppState services are available already from static initialisation code.
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* @warning don't use AppState in destructors.
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*/
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class AppState
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: util::NonCopyable
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{
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private:
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AppState ();
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~AppState ();
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friend class std::default_delete<AppState>;
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public:
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/** get the (single) AppState instance.
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* @warning don't use it after the end of main()! */
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static AppState& instance();
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/** evaluate the result of option parsing and maybe additional configuration
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* such as to be able to determine the further behaviour of the application.
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* Set the internal state within this object accordingly. */
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void init (lumiera::Option& options);
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/** access basic application setup values (from \c setup.ini) */
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string fetchSetupValue (lib::Literal key);
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/** building on the state determined by #init, decide if the given Subsys
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* needs to be pulled up and, if necessary, register the Subsys and its
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* prerequisites to be maintained throughout the application's lifetime.
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*/
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void maybeStart (lumiera::Subsys&);
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enum ExitCode {
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NORMAL_EXIT,
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CLEAN_EXIT_AFTER_ERROR,
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CLEAN_EMERGENCY_EXIT,
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FAILED_EMERGENCY_EXIT
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};
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/** put the main thread of the application into a wait state, as long as some
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* subsystem(s) registered with #maybeStart still need to be maintained.
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* On termination of one of those components, tear down the remaining
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* components and initiate a normal or emergency shutdown of the
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* application, depending on the triggering component's
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* mode of termination (exit or exception).
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* @return global application exit code
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*/
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ExitCode maybeWait();
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/** initiate the controlled error shutdown sequence
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* @param problem causing exception */
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ExitCode abort (lumiera::Error& problem);
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/** initiate an fatal emergency shutdown,
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* caused by an unforeseen error condition */
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ExitCode abort () throw();
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private:
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using PSub = std::unique_ptr<SubsystemRunner>;
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BasicSetup setup_;
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PSub subsystems_;
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bool emergency_;
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bool core_up_;
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};
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} // namespace lumiera
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#endif
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