fsfw/osal/linux/BinarySemaphore.h

#ifndef FRAMEWORK_OSAL_LINUX_BINARYSEMPAHORE_H_
#define FRAMEWORK_OSAL_LINUX_BINARYSEMPAHORE_H_

#include "../../returnvalues/HasReturnvaluesIF.h"
#include "../../tasks/SemaphoreIF.h"

extern "C" {
#include <semaphore.h>
}

/**
 * @brief 	OS Tool to achieve synchronization of between tasks or between
 * 			task and ISR. The default semaphore implementation creates a
 * 			binary semaphore, which can only be taken once.
 * @details
 * See: http://www.man7.org/linux/man-pages/man7/sem_overview.7.html
 * @author 	R. Mueller
 * @ingroup osal
 */
class BinarySemaphore: public SemaphoreIF,
		public HasReturnvaluesIF {
public:
	static const uint8_t INTERFACE_ID = CLASS_ID::SEMAPHORE_IF;

	//! @brief Default ctor
	BinarySemaphore();
	//! @brief Copy ctor, deleted explicitely.
	BinarySemaphore(const BinarySemaphore&) = delete;
	//! @brief Copy assignment, deleted explicitely.
	BinarySemaphore& operator=(const BinarySemaphore&) = delete;
	//! @brief Move ctor
	BinarySemaphore (BinarySemaphore &&);
	//! @brief Move assignment
	BinarySemaphore & operator=(BinarySemaphore &&);
	//! @brief Destructor
	virtual ~BinarySemaphore();

	void initSemaphore(uint8_t initCount = 1);

	uint8_t getSemaphoreCounter() const override;
	static uint8_t getSemaphoreCounter(sem_t* handle);

	/**
	 * Take the binary semaphore.
	 * If the semaphore has already been taken, the task will be blocked
	 * for a maximum of #timeoutMs or until the semaphore is given back,
	 * for example by an ISR or another task.
	 * @param timeoutMs
	 * @return -@c RETURN_OK on success
	 *         -@c SemaphoreIF::SEMAPHORE_TIMEOUT on timeout
	 */
	ReturnValue_t acquire(TimeoutType timeoutType = TimeoutType::BLOCKING,
			uint32_t timeoutMs = 0) override;

	/**
	 * Release the binary semaphore.
	 * @return -@c RETURN_OK on success
	 *         -@c SemaphoreIF::SEMAPHORE_NOT_OWNED if the semaphores is
	 *         	already available.
	 */
	virtual ReturnValue_t release() override;
	/**
	 * This static function can be used to release a semaphore  by providing
	 * its handle.
	 * @param handle
	 * @return
	 */
	static ReturnValue_t release(sem_t* handle);

	/** Checks the validity of the semaphore count against a specified
	 * known maxCount
	 * @param handle
	 * @param maxCount
	 * @return
	 */
	static ReturnValue_t checkCount(sem_t* handle, uint8_t maxCount);
protected:
	sem_t handle;
};

#endif /* FRAMEWORK_OSAL_FREERTOS_BINARYSEMPAHORE_H_ */