#ifndef AVREMU_IPC_H_
#define AVREMU_IPC_H_

#include "util.h"

#include <unistd.h>


/* The sender side of an IPC connection. */
struct ipc_tx {
	/* Filedescriptor for the transmit side of the message pipe. */
	int message_pipe;
	/* Filedescriptor for the result message pipe. */
	int result_pipe;
};

/* The receiver side of an IPC connection. */
struct ipc_rx {
	/* Filedescriptor for the receive side of the message pipe. */
	int message_pipe;
	/* Filedescriptor for the result message pipe. */
	int result_pipe;
};

/* Type of a message result code. */
typedef uint16_t ipc_result_t;
/* Type of a message size descriptor. */
typedef uint16_t ipc_size_t;


/* Create a communication pipe. */
int ipc_pipe_create(struct ipc_tx *tx, struct ipc_rx *rx);
void ipc_pipe_destroy_tx(struct ipc_tx *tx);
void ipc_pipe_destroy_rx(struct ipc_rx *rx);
void ipc_pipe_destroy(struct ipc_tx *tx, struct ipc_rx *rx);

/* Map a given file descriptor to an IPC pipe. */
int ipc_dup2(struct ipc_tx *tx, int fd);

/* Send a message through the IPC pipe.
 * The result (if requested) is returned as a positive number.
 * If an IPC error occured, a negative number is returned. */
int ipc_message_send(struct ipc_tx *tx,
		     const void *message, ipc_size_t msg_size,
		     bool read_result);

/* Poll a message pipe to receive the next message. */
int ipc_message_poll(struct ipc_rx *rx,
		     void *message_buf, ipc_size_t buf_size);

/* Poll a raw line of data from the pipe. */
int ipc_raw_line_poll(struct ipc_rx *rx,
		      char *line_buf, size_t buf_size);

/* Send the result for a message. */
int ipc_send_result(struct ipc_rx *rx, ipc_result_t result_code);

/* Payload data transmission. */
int ipc_payload_send(struct ipc_tx *tx, const void *buf, size_t size);
int ipc_payload_receive(struct ipc_rx *rx, void *buf, size_t size);

#endif /* AVREMU_IPC_H_ */