summaryrefslogtreecommitdiff
path: root/src/poller_base.hpp
blob: 5edb5d4e26be53012a0a758f7dd65d50e1a4c233 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
/*
    Copyright (c) 2010-2012 250bpm s.r.o.
    Copyright (c) 2010-2011 Other contributors as noted in the AUTHORS file

    This file is part of Crossroads project.

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

    Crossroads 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 __XS_POLLER_BASE_HPP_INCLUDED__
#define __XS_POLLER_BASE_HPP_INCLUDED__

#include <map>

#include "fd.hpp"
#include "clock.hpp"
#include "atomic_counter.hpp"

namespace xs
{

    //  Handle of a file descriptor within a pollset.
    typedef void* handle_t;

    // Virtual interface to be exposed by object that want to be notified
    // about events on file descriptors.

    struct i_poll_events
    {
        virtual ~i_poll_events () {}
 
        // Called by I/O thread when file descriptor is ready for reading.
        virtual void in_event (fd_t fd_) = 0;
 
        // Called by I/O thread when file descriptor is ready for writing.
        virtual void out_event (fd_t fd_) = 0;
 
        // Called when timer expires.
        virtual void timer_event (handle_t handle_) = 0;
    };

    class poller_base_t
    {
    public:

        //  Create optimal poller mechanism for this environment.
        static poller_base_t *create ();

        virtual ~poller_base_t ();

        //  Returns load of the poller. Note that this function can be
        //  invoked from a different thread!
        int get_load ();

        virtual handle_t add_fd (fd_t fd_, xs::i_poll_events *events_) = 0;
        virtual void rm_fd (handle_t handle_) = 0;
        virtual void set_pollin (handle_t handle_) = 0;
        virtual void reset_pollin (handle_t handle_) = 0;
        virtual void set_pollout (handle_t handle_) = 0;
        virtual void reset_pollout (handle_t handle_) = 0;
        virtual void start () = 0;
        virtual void stop () = 0;

        //  Add a timeout to expire in timeout_ milliseconds. After the
        //  expiration timer_event on sink_ object will be called.
        handle_t add_timer (int timeout_, xs::i_poll_events *sink_);

        //  Cancel the timer identified by the handle.
        void rm_timer (handle_t handle_);

    protected:

        poller_base_t ();

        //  Called by individual poller implementations to manage the load.
        void adjust_load (int amount_);

        //  Executes any timers that are due. Returns number of milliseconds
        //  to wait to match the next timer or 0 meaning "no timers".
        uint64_t execute_timers ();

    private:

        //  Clock instance private to this I/O thread.
        clock_t clock;

        //  List of active timers.
        struct timer_info_t
        {
            xs::i_poll_events *sink;
            std::multimap <uint64_t, timer_info_t>::iterator self;
        };
        typedef std::multimap <uint64_t, timer_info_t> timers_t;
        timers_t timers;

        //  Load of the poller. Currently the number of file descriptors
        //  registered.
        atomic_counter_t load;

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

}

#endif