cras/src/server/cras_rclient.h

/* Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

/*
 * A remote client to the server.
 */
#ifndef CRAS_RCLIENT_H_
#define CRAS_RCLIENT_H_

#include "cras_types.h"

struct cras_client_message;
struct cras_message;
struct cras_server_message;

/* An attached client.
 *  id - The id of the client.
 *  fd - Connection for client communication.
 *  ops - cras_rclient_ops for the cras_rclient.
 *  supported_directions - Bit mask for supported stream directions.
 *  client_type - Client type of this rclient. If this is set to value other
 *                than CRAS_CLIENT_TYPE_UNKNOWN, rclient will overwrite incoming
 *                messages' client type.
 */
struct cras_rclient {
	struct cras_observer_client *observer;
	size_t id;
	int fd;
	const struct cras_rclient_ops *ops;
	int supported_directions;
	enum CRAS_CLIENT_TYPE client_type;
};

/* Operations for cras_rclient.
 * handle_message_from_client - Entry point for handling a message from the
 * corresponded client.
 * send_message_to_client - Method for sending message to the corresponded
 * client.
 * destroy - Method to destroy and free the cras_rclient.
 */
struct cras_rclient_ops {
	int (*handle_message_from_client)(struct cras_rclient *,
					  const struct cras_server_message *,
					  int *fds, unsigned int num_fds);
	int (*send_message_to_client)(const struct cras_rclient *,
				      const struct cras_client_message *,
				      int *fds, unsigned int num_fds);
	void (*destroy)(struct cras_rclient *);
};

/* Creates an rclient structure.
 * Args:
 *    fd - The file descriptor used for communication with the client.
 *    id - Unique identifier for this client.
 *    conn_type - Client connection type.
 * Returns:
 *    A pointer to the newly created rclient on success, NULL on failure.
 */
struct cras_rclient *cras_rclient_create(int fd, size_t id,
					 enum CRAS_CONNECTION_TYPE conn_type);

/* Destroys an rclient created with "cras_rclient_create".
 * Args:
 *    client - The client to destroy.
 */
void cras_rclient_destroy(struct cras_rclient *client);

/* Handles a received buffer from the client.
 * Args:
 *    client - The client that received this message.
 *    buf - The raw byte buffer the client sent. It should contain a valid
 *      cras_server_message.
 *    buf_len - The length of |buf|.
 *    fds - Array of valid file descriptors sent by the remote client.
 *    num_fds - Length of |fds|.
 * Returns:
 *    0 on success, otherwise a negative error code.
 */
int cras_rclient_buffer_from_client(struct cras_rclient *client,
				    const uint8_t *buf, size_t buf_len,
				    int *fds, int num_fds);

/* Sends a message to the client.
 * Args:
 *    client - The client to send the message to.
 *    msg - The message to send.
 *    fds - Array of file descriptors or null
 *    num_fds - Number of entries in the fds array.
 * Returns:
 *    number of bytes written on success, otherwise a negative error code.
 */
int cras_rclient_send_message(const struct cras_rclient *client,
			      const struct cras_client_message *msg, int *fds,
			      unsigned int num_fds);

#endif /* CRAS_RCLIENT_H_ */