socket.h

/*
 * Copyright (C) 2015 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef __ADB_SOCKET_H
#define __ADB_SOCKET_H

#include <stddef.h>

#include "fdevent.h"

struct apacket;
class atransport;

/* An asocket represents one half of a connection between a local and
** remote entity.  A local asocket is bound to a file descriptor.  A
** remote asocket is bound to the protocol engine.
*/
struct asocket {
        /* chain pointers for the local/remote list of
        ** asockets that this asocket lives in
        */
    asocket *next;
    asocket *prev;

        /* the unique identifier for this asocket
        */
    unsigned id;

        /* flag: set when the socket's peer has closed
        ** but packets are still queued for delivery
        */
    int    closing;

    // flag: set when the socket failed to write, so the socket will not wait to
    // write packets and close directly.
    bool has_write_error;

        /* flag: quit adbd when both ends close the
        ** local service socket
        */
    int    exit_on_close;

        /* the asocket we are connected to
        */

    asocket *peer;

        /* For local asockets, the fde is used to bind
        ** us to our fd event system.  For remote asockets
        ** these fields are not used.
        */
    fdevent fde;
    int fd;

        /* queue of apackets waiting to be written
        */
    apacket *pkt_first;
    apacket *pkt_last;

        /* enqueue is called by our peer when it has data
        ** for us.  It should return 0 if we can accept more
        ** data or 1 if not.  If we return 1, we must call
        ** peer->ready() when we once again are ready to
        ** receive data.
        */
    int (*enqueue)(asocket *s, apacket *pkt);

        /* ready is called by the peer when it is ready for
        ** us to send data via enqueue again
        */
    void (*ready)(asocket *s);

        /* shutdown is called by the peer before it goes away.
        ** the socket should not do any further calls on its peer.
        ** Always followed by a call to close. Optional, i.e. can be NULL.
        */
    void (*shutdown)(asocket *s);

        /* close is called by the peer when it has gone away.
        ** we are not allowed to make any further calls on the
        ** peer once our close method is called.
        */
    void (*close)(asocket *s);

        /* A socket is bound to atransport */
    atransport *transport;

    size_t get_max_payload() const;
};

asocket *find_local_socket(unsigned local_id, unsigned remote_id);
void install_local_socket(asocket *s);
void remove_socket(asocket *s);
void close_all_sockets(atransport *t);

asocket *create_local_socket(int fd);
asocket *create_local_service_socket(const char* destination,
                                     const atransport* transport);

asocket *create_remote_socket(unsigned id, atransport *t);
void connect_to_remote(asocket *s, const char *destination);
void connect_to_smartsocket(asocket *s);

#endif  // __ADB_SOCKET_H