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/*
* Copyright (C) 2022 Linux Studio Plugins Project <https://lsp-plug.in/>
* (C) 2022 Vladimir Sadovnikov <sadko4u@gmail.com>
*
* This file is part of lsp-common-lib
* Created on: 4 нояб. 2022 г.
*
* lsp-common-lib is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* any later version.
*
* lsp-common-lib 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with lsp-common-lib. If not, see <https://www.gnu.org/licenses/>.
*/
#ifndef LSP_PLUG_IN_COMMON_SINGLETONE_H_
#define LSP_PLUG_IN_COMMON_SINGLETONE_H_
#include <lsp-plug.in/common/version.h>
#include <lsp-plug.in/common/atomic.h>
namespace lsp
{
/**
* Singletone barrier that holds information about the initialization of the singletone
*/
struct LSP_COMMON_LIB_PUBLIC singletone_t
{
private:
enum {
ST_UNINITIALIZED,
ST_INITIALIZING,
ST_INITIALIZED
};
volatile uatomic_t state;
public:
explicit singletone_t() { state = ST_UNINITIALIZED; }
~ singletone_t() { }
public:
/** Check that singletone data the barrier is responsible for is not initialized
*
* @return true if singletone is initialized
*/
inline bool uninitialized() const { return state == ST_UNINITIALIZED; }
/** Check that singletone data the barrier is responsible for is initialized
*
* @return true if singletone is initialized
*/
inline bool initialized() const { return state == ST_INITIALIZED; }
/** Check that singletone data the barrier is responsible for is in initialization state
*
* @return true if singletone is initialized
*/
inline bool initializing() const { return state == ST_INITIALIZING; }
/** Lock singletone barrier for initialization process
*
* @return true if the caller thread has acquired lock of the singletone for initialization
*/
bool lock_for_initialization();
/**
* Mark singletone barrier as initialized
* @return true if state has changed to initialized
*/
bool mark_initialized();
};
typedef struct singletone_t singletone_t;
struct SingletoneInitializer
{
private:
singletone_t & singletone;
public:
explicit inline SingletoneInitializer(singletone_t & in_singletone): singletone(in_singletone) {}
template <class T>
inline void operator + (T & actor)
{
if (!singletone.lock_for_initialization())
return;
actor();
singletone.mark_initialized();
}
template <class T>
inline void operator + (T && actor)
{
if (!singletone.lock_for_initialization())
return;
actor();
singletone.mark_initialized();
}
};
#define lsp_impl_singletone_init0(singletone, id) \
SingletoneInitializer(singletone) + [&]() -> void
#define lsp_singletone_init(singletone) lsp_impl_singletone_init0((singletone), __COUNTER__)
} /* namespace lsp */
#endif /* LSP_PLUG_IN_COMMON_SINGLETONE_H_ */
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