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0ad/source/lib/module_init.h

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/* Copyright (C) 2009 Wildfire Games.
* This file is part of 0 A.D.
*
* 0 A.D. 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.
*
* 0 A.D. 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 0 A.D. If not, see <http://www.gnu.org/licenses/>.
*/
/*
* helpers for module initialization/shutdown.
*/
#ifndef INCLUDED_MODULE_INIT
#define INCLUDED_MODULE_INIT
/**
* initialization state of a module: class, source file, or whatever.
*
* can be declared as a static variable => no initializer needed,
* since 0 is the correct initial value.
*
* DO NOT change the value directly! (that'd break the carefully thought-out
* lock-free implementation)
**/
typedef uintptr_t ModuleInitState; // uintptr_t required by cpu_CAS
/**
* @return whether initialization should go forward, i.e. initState is
* currently MODULE_UNINITIALIZED. increments initState afterwards.
*
* (the reason for this function - and tricky part - is thread-safety)
**/
extern bool ModuleShouldInitialize(volatile ModuleInitState* initState);
/**
* if module reference count is valid, decrement it.
* @return whether shutdown should go forward, i.e. this is the last
* shutdown call.
**/
extern bool ModuleShouldShutdown(volatile ModuleInitState* initState);
/**
* indicate the module is unusable, e.g. due to failure during init.
* all subsequent ModuleShouldInitialize/ModuleShouldShutdown calls
* for this initState will return false.
**/
extern void ModuleSetError(volatile ModuleInitState* initState);
/**
* @return whether the module is in the failure state, i.e. ModuleSetError
* was previously called on the same initState.
*
* this function is provided so that modules can report init failure to
* the second or later caller.
**/
extern bool ModuleIsError(volatile ModuleInitState* initState);
#endif // #ifndef INCLUDED_MODULE_INIT