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
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156

extern crate mio;
extern crate tokio_io;


use std::{
    io,
    ops::Deref,
    sync::Arc,
};

use self::{
    mio::{
        event::Evented,
        unix::EventedFd,
    },
    tokio_io::AsyncRead,
};
use futures::{
    Async,
    Poll,
    Stream,
};
use tokio_reactor::{
    Handle,
    PollEvented,
};

use events::{
    Event,
    EventOwned,
};
use fd_guard::FdGuard;
use util::read_into_buffer;


/// Stream of inotify events
///
/// Allows for streaming events returned by [`Inotify::event_stream`].
///
/// [`Inotify::event_stream`]: struct.Inotify.html#method.event_stream
pub struct EventStream<'buffer> {
    fd: PollEvented<EventedFdGuard>,
    buffer: &'buffer mut [u8],
    buffer_pos: usize,
    unused_bytes: usize,
}

impl<'buffer> EventStream<'buffer> {
    /// Returns a new `EventStream` associated with the default reactor.
    pub(crate) fn new(fd: Arc<FdGuard>, buffer: &'buffer mut [u8]) -> Self {
        EventStream {
            fd: PollEvented::new(EventedFdGuard(fd)),
            buffer: buffer,
            buffer_pos: 0,
            unused_bytes: 0,
        }
    }

    /// Returns a new `EventStream` associated with the specified reactor.
     pub(crate) fn new_with_handle(
        fd    : Arc<FdGuard>,
        handle: &Handle,
        buffer: &'buffer mut [u8],
    )
        -> io::Result<Self>
    {
        Ok(EventStream {
            fd: PollEvented::new_with_handle(EventedFdGuard(fd), handle)?,
            buffer: buffer,
            buffer_pos: 0,
            unused_bytes: 0,
        })
    }
}

impl<'buffer> Stream for EventStream<'buffer> {
    type Item = EventOwned;
    type Error = io::Error;

    fn poll(&mut self) -> Poll<Option<Self::Item>, Self::Error>
    {
        if self.unused_bytes == 0 {
            // Nothing usable in buffer. Need to reset and fill buffer.
            self.buffer_pos   = 0;
            self.unused_bytes = try_ready!(self.fd.poll_read(&mut self.buffer));
        }

        if self.unused_bytes == 0 {
            // The previous read returned `0` signalling end-of-file. Let's
            // signal end-of-stream to the caller.
            return Ok(Async::Ready(None));
        }

        // We have bytes in the buffer. inotify doesn't put partial events in
        // there, and we only take complete events out. That means we have at
        // least one event in there and can call `from_buffer` to take it out.
        let (bytes_consumed, event) = Event::from_buffer(
            Arc::downgrade(self.fd.get_ref()),
            &self.buffer[self.buffer_pos..],
        );
        self.buffer_pos   += bytes_consumed;
        self.unused_bytes -= bytes_consumed;

        Ok(Async::Ready(Some(event.into_owned())))
    }
}

#[derive(Clone, Debug, PartialEq)]
struct EventedFdGuard(Arc<FdGuard>);

impl Evented for EventedFdGuard {
    #[inline]
    fn register(&self,
                poll: &mio::Poll,
                token: mio::Token,
                interest: mio::Ready,
                opts: mio::PollOpt)
                -> io::Result<()>
    {
        EventedFd(&(self.fd)).register(poll, token, interest, opts)
    }

    #[inline]
    fn reregister(&self,
                  poll: &mio::Poll,
                  token: mio::Token,
                  interest: mio::Ready,
                  opts: mio::PollOpt)
                  -> io::Result<()>
    {
        EventedFd(&(self.fd)).reregister(poll, token, interest, opts)
    }

    #[inline]
    fn deregister(&self, poll: &mio::Poll) -> io::Result<()> {
        EventedFd(&self.fd).deregister(poll)
    }
}

impl io::Read for EventedFdGuard {
    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
        match read_into_buffer(self.fd, buf) {
            i if i >= 0 => Ok(i as usize),
            _ => Err(io::Error::last_os_error()),
        }
    }
}

impl Deref for EventedFdGuard {
    type Target = Arc<FdGuard>;
    #[inline]
    fn deref(&self) -> &Self::Target {
        &self.0
    }

}