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construct/include/ircd/runlevel.h

81 lines
2.8 KiB
C++

// Matrix Construct
//
// Copyright (C) Matrix Construct Developers, Authors & Contributors
// Copyright (C) 2016-2018 Jason Volk <jason@zemos.net>
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice is present in all copies. The
// full license for this software is available in the LICENSE file.
#define HAVE_IRCD_IRCD_RUNLEVEL_H
namespace ircd
{
enum class runlevel :int;
struct runlevel_changed;
extern const enum runlevel &runlevel;
string_view reflect(const enum runlevel &);
bool runlevel_set(const enum runlevel &);
}
// Forward declarations for because ctx.h is included after runlevel.h.
namespace ircd::ctx
{
struct dock;
}
/// An instance of this class registers itself to be called back when
/// the ircd::runlevel has changed.
///
/// Note: Its destructor will access a list in libircd; after a callback
/// for a HALT do not unload libircd.so until destructing this object.
///
/// A static ctx::dock is also available for contexts to wait for a runlevel
/// change notification.
///
struct ircd::runlevel_changed
:instance_list<ircd::runlevel_changed>
,std::function<void (const enum runlevel &)>
{
using handler = std::function<void (const enum runlevel &)>;
// Users on an ircd::ctx who wish to use the dock interface to wait for
// a runlevel change can directly access this static instance.
static ctx::dock dock;
/// The handler function will be called back for any runlevel change while
/// this instance remains in scope.
runlevel_changed(handler function);
~runlevel_changed() noexcept;
};
/// The runlevel allows all observers to know the coarse state of IRCd and to
/// react accordingly. This can be used by the embedder of libircd to know
/// when it's safe to use or delete libircd resources. It is also used
/// similarly by the library and its modules.
///
/// Primary modes:
///
/// * HALT is the off mode. Nothing is/will be running in libircd until
/// an invocation of ircd::init();
///
/// * RUN is the service mode. Full client and application functionality
/// exists in this mode. Leaving the RUN mode is done with ircd::quit();
///
/// - Transitional modes: Modes which are working towards the next mode.
/// - Interventional modes: Modes which are *not* working towards the next
/// mode and may require some user action to continue.
///
enum class ircd::runlevel
:int
{
HALT = 0, ///< [inter] IRCd Powered off.
READY = 1, ///< [inter] Ready for user to run ios event loop.
START = 2, ///< [trans] Starting up subsystems for service.
RUN = 3, ///< [inter] IRCd in service.
QUIT = 4, ///< [trans] Clean shutdown in progress
FAULT = -1, ///< [trans] QUIT with exception (dirty shutdown)
};