socket_base.hpp

/*
    Copyright (c) 2007-2016 Contributors as noted in the AUTHORS file

    This file is part of libzmq, the ZeroMQ core engine in C++.

    libzmq is free software; you can redistribute it and/or modify it under
    the terms of the GNU Lesser General Public License (LGPL) as published
    by the Free Software Foundation; either version 3 of the License, or
    (at your option) any later version.

    As a special exception, the Contributors give you permission to link
    this library with independent modules to produce an executable,
    regardless of the license terms of these independent modules, and to
    copy and distribute the resulting executable under terms of your choice,
    provided that you also meet, for each linked independent module, the
    terms and conditions of the license of that module. An independent
    module is a module which is not derived from or based on this library.
    If you modify this library, you must extend this exception to your
    version of the library.

    libzmq is distributed in the hope that it will be useful, but WITHOUT
    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
    License for more details.

    You should have received a copy of the GNU Lesser General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#ifndef __ZMQ_SOCKET_BASE_HPP_INCLUDED__
#define __ZMQ_SOCKET_BASE_HPP_INCLUDED__

#include <string>
#include <map>
#include <stdarg.h>

#include "own.hpp"
#include "array.hpp"
#include "blob.hpp"
#include "stdint.hpp"
#include "poller.hpp"
#include "atomic_counter.hpp"
#include "i_poll_events.hpp"
#include "i_mailbox.hpp"
#include "stdint.hpp"
#include "clock.hpp"
#include "pipe.hpp"

extern "C"
{
    void zmq_free_event (void *data, void *hint);
}

namespace zmq
{

    class ctx_t;
    class msg_t;
    class pipe_t;

    class socket_base_t :
        public own_t,
        public array_item_t <>,
        public i_poll_events,
        public i_pipe_events
    {
        friend class reaper_t;

    public:

        //  Returns false if object is not a socket.
        bool check_tag ();

        //  Create a socket of a specified type.
        static socket_base_t *create (int type_, zmq::ctx_t *parent_,
            uint32_t tid_, int sid_);

        //  Returns the mailbox associated with this socket.
        i_mailbox *get_mailbox ();

        //  Interrupt blocking call if the socket is stuck in one.
        //  This function can be called from a different thread!
        void stop ();

        //  Interface for communication with the API layer.
        int setsockopt (int option_, const void *optval_, size_t optvallen_);
        int getsockopt (int option_, void *optval_, size_t *optvallen_);
        int bind (const char *addr_);
        int connect (const char *addr_);
        int term_endpoint (const char *addr_);
        int send (zmq::msg_t *msg_, int flags_);
        int recv (zmq::msg_t *msg_, int flags_);
        int add_signaler (signaler_t *s);
        int remove_signaler (signaler_t *s);
        int close ();

        //  These functions are used by the polling mechanism to determine
        //  which events are to be reported from this socket.
        bool has_in ();
        bool has_out ();

        //  Joining and leaving groups
        int join (const char *group);
        int leave (const char *group);

        //  Using this function reaper thread ask the socket to register with
        //  its poller.
        void start_reaping (poller_t *poller_);

        //  i_poll_events implementation. This interface is used when socket
        //  is handled by the poller in the reaper thread.
        void in_event ();
        void out_event ();
        void timer_event (int id_);

        //  i_pipe_events interface implementation.
        void read_activated (pipe_t *pipe_);
        void write_activated (pipe_t *pipe_);
        void hiccuped (pipe_t *pipe_);
        void pipe_terminated (pipe_t *pipe_);
        void lock();
        void unlock();

        int monitor (const char *endpoint_, int events_);

        void set_fd(fd_t fd_);
        fd_t fd();

        void event_connected (const std::string &addr_, int fd_);
        void event_connect_delayed (const std::string &addr_, int err_);
        void event_connect_retried (const std::string &addr_, int interval_);
        void event_listening (const std::string &addr_, int fd_);
        void event_bind_failed (const std::string &addr_, int err_);
        void event_accepted (const std::string &addr_, int fd_);
        void event_accept_failed (const std::string &addr_, int err_);
        void event_closed (const std::string &addr_, int fd_);
        void event_close_failed (const std::string &addr_, int fd_);
        void event_disconnected (const std::string &addr_, int fd_);

    protected:

        socket_base_t (zmq::ctx_t *parent_, uint32_t tid_, int sid_, bool thread_safe_ = false);
        virtual ~socket_base_t ();

        //  Concrete algorithms for the x- methods are to be defined by
        //  individual socket types.
        virtual void xattach_pipe (zmq::pipe_t *pipe_,
            bool subscribe_to_all_ = false) = 0;

        //  The default implementation assumes there are no specific socket
        //  options for the particular socket type. If not so, override this
        //  method.
        virtual int xsetsockopt (int option_, const void *optval_,
            size_t optvallen_);

        //  The default implementation assumes that send is not supported.
        virtual bool xhas_out ();
        virtual int xsend (zmq::msg_t *msg_);

        //  The default implementation assumes that recv in not supported.
        virtual bool xhas_in ();
        virtual int xrecv (zmq::msg_t *msg_);

        //  Returns the credential for the peer from which we have received
        //  the last message. If no message has been received yet,
        //  the function returns empty credential.
        virtual blob_t get_credential () const;

        //  i_pipe_events will be forwarded to these functions.
        virtual void xread_activated (pipe_t *pipe_);
        virtual void xwrite_activated (pipe_t *pipe_);
        virtual void xhiccuped (pipe_t *pipe_);
        virtual void xpipe_terminated (pipe_t *pipe_) = 0;

        //  the default implementation assumes that joub and leave are not supported.
        virtual int xjoin (const char *group_);
        virtual int xleave (const char *group_);

        //  Delay actual destruction of the socket.
        void process_destroy ();

        // Socket event data dispatch
        void monitor_event (int event_, int value_, const std::string& addr_);

        // Monitor socket cleanup
        void stop_monitor (bool send_monitor_stopped_event_ = true);

        // Next assigned name on a zmq_connect() call used by ROUTER and STREAM socket types
        std::string connect_rid;

    private:
        //  Creates new endpoint ID and adds the endpoint to the map.
        void add_endpoint (const char *addr_, own_t *endpoint_, pipe_t *pipe);

        //  Map of open endpoints.
        typedef std::pair <own_t *, pipe_t*> endpoint_pipe_t;
        typedef std::multimap <std::string, endpoint_pipe_t> endpoints_t;
        endpoints_t endpoints;

        //  Map of open inproc endpoints.
        typedef std::multimap <std::string, pipe_t *> inprocs_t;
        inprocs_t inprocs;

        //  To be called after processing commands or invoking any command
        //  handlers explicitly. If required, it will deallocate the socket.
        void check_destroy ();

        //  Moves the flags from the message to local variables,
        //  to be later retrieved by getsockopt.
        void extract_flags (msg_t *msg_);

        //  Used to check whether the object is a socket.
        uint32_t tag;

        //  If true, associated context was already terminated.
        bool ctx_terminated;

        //  If true, object should have been already destroyed. However,
        //  destruction is delayed while we unwind the stack to the point
        //  where it doesn't intersect the object being destroyed.
        bool destroyed;

        //  Parse URI string.
        int parse_uri (const char *uri_, std::string &protocol_,
            std::string &address_);

        //  Check whether transport protocol, as specified in connect or
        //  bind, is available and compatible with the socket type.
        int check_protocol (const std::string &protocol_);

        //  Register the pipe with this socket.
        void attach_pipe (zmq::pipe_t *pipe_, bool subscribe_to_all_ = false);

        //  Processes commands sent to this socket (if any). If timeout is -1,
        //  returns only after at least one command was processed.
        //  If throttle argument is true, commands are processed at most once
        //  in a predefined time period.
        int process_commands (int timeout_, bool throttle_);

        //  Handlers for incoming commands.
        void process_stop ();
        void process_bind (zmq::pipe_t *pipe_);
        void process_term (int linger_);

        void update_pipe_options(int option_);

        //  Socket's mailbox object.
        i_mailbox *mailbox;

        //  List of attached pipes.
        typedef array_t <pipe_t, 3> pipes_t;
        pipes_t pipes;

        //  Reaper's poller and handle of this socket within it.
        poller_t *poller;
        poller_t::handle_t handle;

        //  Timestamp of when commands were processed the last time.
        uint64_t last_tsc;

        //  Number of messages received since last command processing.
        int ticks;

        //  True if the last message received had MORE flag set.
        bool rcvmore;

        // File descriptor if applicable
        fd_t file_desc;

        //  Improves efficiency of time measurement.
        clock_t clock;

        // Monitor socket;
        void *monitor_socket;

        // Bitmask of events being monitored
        int monitor_events;

        // Last socket endpoint resolved URI
        std::string last_endpoint;

        // Indicate if the socket is thread safe
        bool thread_safe;

        // Signaler to be used in the reaping stage
        signaler_t* reaper_signaler;

        // Mutex for synchronize access to the socket in thread safe mode
        mutex_t sync;

        socket_base_t (const socket_base_t&);
        const socket_base_t &operator = (const socket_base_t&);
    };

}

#endif