fsfw/osal/linux/MessageQueue.h
2020-08-13 20:53:35 +02:00

182 lines
8.6 KiB
C++

#ifndef MESSAGEQUEUE_H_
#define MESSAGEQUEUE_H_
#include "../../internalError/InternalErrorReporterIF.h"
#include "../../ipc/MessageQueueIF.h"
#include "../../ipc/MessageQueueMessage.h"
#include <mqueue.h>
/**
* @brief This class manages sending and receiving of message queue messages.
*
* @details
* Message queues are used to pass asynchronous messages between processes.
* They work like post boxes, where all incoming messages are stored in FIFO
* order. This class creates a new receiving queue and provides methods to fetch
* received messages. Being a child of MessageQueueSender, this class also
* provides methods to send a message to a user-defined or a default destination.
* In addition it also provides a reply method to answer to the queue it
* received its last message from.
*
* The MessageQueue should be used as "post box" for a single owning object.
* So all message queue communication is "n-to-one".
*
* The creation of message queues, as well as sending and receiving messages,
* makes use of the operating system calls provided.
* @ingroup message_queue
*/
class MessageQueue : public MessageQueueIF {
friend class MessageQueueSenderIF;
public:
/**
* @brief The constructor initializes and configures the message queue.
* @details By making use of the according operating system call, a message queue is created
* and initialized. The message depth - the maximum number of messages to be
* buffered - may be set with the help of a parameter, whereas the message size is
* automatically set to the maximum message queue message size. The operating system
* sets the message queue id, or i case of failure, it is set to zero.
* @param message_depth The number of messages to be buffered before passing an error to the
* sender. Default is three.
* @param max_message_size With this parameter, the maximum message size can be adjusted.
* This should be left default.
*/
MessageQueue(uint32_t messageDepth = 3,
size_t maxMessageSize = MessageQueueMessage::MAX_MESSAGE_SIZE );
/**
* @brief The destructor deletes the formerly created message queue.
* @details This is accomplished by using the delete call provided by the operating system.
*/
virtual ~MessageQueue();
/**
* @brief This operation sends a message to the given destination.
* @details It directly uses the sendMessage call of the MessageQueueSender parent, but passes its
* queue id as "sentFrom" parameter.
* @param sendTo This parameter specifies the message queue id of the destination message queue.
* @param message A pointer to a previously created message, which is sent.
* @param ignoreFault If set to true, the internal software fault counter is not incremented if queue is full.
*/
virtual ReturnValue_t sendMessage(MessageQueueId_t sendTo,
MessageQueueMessage* message, bool ignoreFault = false );
/**
* @brief This operation sends a message to the default destination.
* @details As in the sendMessage method, this function uses the sendToDefault call of the
* MessageQueueSender parent class and adds its queue id as "sentFrom" information.
* @param message A pointer to a previously created message, which is sent.
*/
virtual ReturnValue_t sendToDefault( MessageQueueMessage* message );
/**
* @brief This operation sends a message to the last communication partner.
* @details This operation simplifies answering an incoming message by using the stored
* lastParnter information as destination. If there was no message received yet
* (i.e. lastPartner is zero), an error code is returned.
* @param message A pointer to a previously created message, which is sent.
*/
ReturnValue_t reply( MessageQueueMessage* message );
/**
* @brief This function reads available messages from the message queue and returns the sender.
* @details It works identically to the other receiveMessage call, but in addition returns the
* sender's queue id.
* @param message A pointer to a message in which the received data is stored.
* @param receivedFrom A pointer to a queue id in which the sender's id is stored.
*/
ReturnValue_t receiveMessage(MessageQueueMessage* message,
MessageQueueId_t *receivedFrom);
/**
* @brief This function reads available messages from the message queue.
* @details If data is available it is stored in the passed message pointer. The message's
* original content is overwritten and the sendFrom information is stored in the
* lastPartner attribute. Else, the lastPartner information remains untouched, the
* message's content is cleared and the function returns immediately.
* @param message A pointer to a message in which the received data is stored.
*/
ReturnValue_t receiveMessage(MessageQueueMessage* message);
/**
* Deletes all pending messages in the queue.
* @param count The number of flushed messages.
* @return RETURN_OK on success.
*/
ReturnValue_t flush(uint32_t* count);
/**
* @brief This method returns the message queue id of the last communication partner.
*/
MessageQueueId_t getLastPartner() const;
/**
* @brief This method returns the message queue id of this class's message queue.
*/
MessageQueueId_t getId() const;
/**
* \brief With the sendMessage call, a queue message is sent to a receiving queue.
* \param sendTo This parameter specifies the message queue id to send the message to.
* \param message This is a pointer to a previously created message, which is sent.
* \param sentFrom The sentFrom information can be set to inject the sender's queue id into the message.
* This variable is set to zero by default.
* \param ignoreFault If set to true, the internal software fault counter is not incremented if queue is full.
*/
virtual ReturnValue_t sendMessageFrom( MessageQueueId_t sendTo, MessageQueueMessage* message, MessageQueueId_t sentFrom, bool ignoreFault = false );
/**
* \brief The sendToDefault method sends a queue message to the default destination.
* \details In all other aspects, it works identical to the sendMessage method.
* \param message This is a pointer to a previously created message, which is sent.
* \param sentFrom The sentFrom information can be set to inject the sender's queue id into the message.
* This variable is set to zero by default.
*/
virtual ReturnValue_t sendToDefaultFrom( MessageQueueMessage* message, MessageQueueId_t sentFrom = NO_QUEUE, bool ignoreFault = false );
/**
* \brief This method is a simple setter for the default destination.
*/
void setDefaultDestination(MessageQueueId_t defaultDestination);
/**
* \brief This method is a simple getter for the default destination.
*/
MessageQueueId_t getDefaultDestination() const;
bool isDefaultDestinationSet() const;
protected:
/**
* Implementation to be called from any send Call within MessageQueue and MessageQueueSenderIF
* \details This method takes the message provided, adds the sentFrom information and passes
* it on to the destination provided with an operating system call. The OS's return
* value is returned.
* \param sendTo This parameter specifies the message queue id to send the message to.
* \param message This is a pointer to a previously created message, which is sent.
* \param sentFrom The sentFrom information can be set to inject the sender's queue id into the message.
* This variable is set to zero by default.
* \param ignoreFault If set to true, the internal software fault counter is not incremented if queue is full.
*/
static ReturnValue_t sendMessageFromMessageQueue(MessageQueueId_t sendTo,MessageQueueMessage* message, MessageQueueId_t sentFrom = NO_QUEUE,bool ignoreFault=false);
private:
/**
* @brief The class stores the queue id it got assigned from the operating system in this attribute.
* If initialization fails, the queue id is set to zero.
*/
MessageQueueId_t id;
/**
* @brief In this attribute, the queue id of the last communication partner is stored
* to allow for replying.
*/
MessageQueueId_t lastPartner;
/**
* @brief The message queue's name -a user specific information for the operating system- is
* generated automatically with the help of this static counter.
*/
/**
* \brief This attribute stores a default destination to send messages to.
* \details It is stored to simplify sending to always-the-same receiver. The attribute may
* be set in the constructor or by a setter call to setDefaultDestination.
*/
MessageQueueId_t defaultDestination;
/**
* The name of the message queue, stored for unlinking
*/
char name[5];
static uint16_t queueCounter;
ReturnValue_t handleError(mq_attr* attributes, uint32_t messageDepth);
};
#endif /* MESSAGEQUEUE_H_ */