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/**
* \file
* \brief DeferredThreadDeleter class header
*
* \author Copyright (C) 2015 Kamil Szczygiel http://www.distortec.com http://www.freddiechopin.info
*
* \par License
* This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0. If a copy of the MPL was not
* distributed with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
*/
#ifndef INCLUDE_DISTORTOS_INTERNAL_MEMORY_DEFERREDTHREADDELETER_HPP_
#define INCLUDE_DISTORTOS_INTERNAL_MEMORY_DEFERREDTHREADDELETER_HPP_
#include "distortos/distortosConfiguration.h"
#ifdef CONFIG_THREAD_DETACH_ENABLE
#include "distortos/Mutex.hpp"
namespace distortos
{
namespace internal
{
/// DeferredThreadDeleter class can be used to defer deletion of dynamic detached threads
class DeferredThreadDeleter
{
public:
/**
* \brief DeferredThreadDeleter's constructor
*/
constexpr DeferredThreadDeleter() :
list_{},
mutex_{Mutex::Type::normal, Mutex::Protocol::priorityInheritance},
notEmpty_{}
{
}
/**
* \brief DeferredThreadDeleter's function call operator
*
* Adds thread to internal list of threads scheduled for deferred deletion and marks the list as "not empty".
*
* \note The object must be locked (with a successful call to DeferredThreadDeleter::lock()) before this function is
* used!
*
* \param [in] threadControlBlock is a reference to ThreadControlBlock object associated with dynamic and detached
* thread that has terminated its execution
*
* \return 0 on success, error code otherwise:
* - error codes returned by Mutex::unlock();
*/
int operator()(ThreadControlBlock& threadControlBlock);
/**
* \brief Locks the object, preparing it for adding thread to internal list.
*
* Locks the mutex that synchronizes access to internal list. Locking (performed in this function) and unlocking
* (performed at the end of function call operator) are separated, because the locking must be done while the thread
* is still runnable, while the transfer to internal list is performed when the thread is not in this state.
*
* \note This function must be called before function call operator is used!
*
* \return 0 on success, error code otherwise:
* - error codes returned by Mutex::lock();
*/
int lock();
/**
* \brief Tries to perform deferred deletion of threads.
*
* Does nothing is the list is not marked as "not empty". Otherwise this function first tries to lock following two
* mutexes:
* - mutex that protects dynamic memory allocator;
* - mutex that synchronizes access to list of threads scheduled for deferred deletion;
* If any Mutex::tryLock() call fails, this function just returns (unlocking any mutexes is necessary). Otherwise
* the threads are removed from the list and deleted, while the list's "not empty" marker is cleared.
*
* \return 0 on success, error code otherwise:
* - error codes returned by Mutex::tryLock();
* - error codes returned by Mutex::unlock();
*/
int tryCleanup();
private:
/**
* \brief Internals of tryCleanup().
*
* \return 0 on success, error code otherwise:
* - error codes returned by Mutex::tryLock();
* - error codes returned by Mutex::unlock();
*/
int tryCleanupInternal();
/// list of threads scheduled for deferred deletion
ThreadList::UnsortedIntrusiveList list_;
/// mutex that synchronizes access to the \a list_
Mutex mutex_;
/// true if \a list_ is not empty, false otherwise
bool notEmpty_;
};
} // namespace internal
} // namespace distortos
#endif // def CONFIG_THREAD_DETACH_ENABLE
#endif // INCLUDE_DISTORTOS_INTERNAL_MEMORY_DEFERREDTHREADDELETER_HPP_
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