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extern crate syscall;
use std::collections::BTreeMap;
use std::fs::File;
use std::io::{Read, Error, Result};
use std::os::unix::io::RawFd;
pub struct EventQueue<R> {
file: File,
callbacks: BTreeMap<RawFd, Box<FnMut(usize) -> Result<Option<R>>>>
}
impl<R> EventQueue<R> {
pub fn new() -> Result<EventQueue<R>> {
Ok(EventQueue {
file: File::open("event:")?,
callbacks: BTreeMap::new()
})
}
pub fn add<F: FnMut(usize) -> Result<Option<R>> + 'static>(&mut self, fd: RawFd, callback: F) -> Result<()> {
syscall::fevent(fd as usize, syscall::EVENT_READ).map_err(|x| Error::from_raw_os_error(x.errno))?;
self.callbacks.insert(fd, Box::new(callback));
Ok(())
}
pub fn remove(&mut self, fd: RawFd) -> Result<Option<Box<FnMut(usize) -> Result<Option<R>>>>> {
if let Some(callback) = self.callbacks.remove(&fd) {
syscall::fevent(fd as usize, 0).map_err(|x| Error::from_raw_os_error(x.errno))?;
Ok(Some(callback))
} else {
Ok(None)
}
}
pub fn trigger(&mut self, fd: RawFd, count: usize) -> Result<Option<R>> {
if let Some(callback) = self.callbacks.get_mut(&fd) {
callback(count)
} else {
Ok(None)
}
}
pub fn trigger_all(&mut self, count: usize) -> Result<Vec<R>> {
let mut rets = Vec::new();
for (_fd, callback) in self.callbacks.iter_mut() {
if let Some(ret) = callback(count)? {
rets.push(ret);
}
}
Ok(rets)
}
pub fn run(&mut self) -> Result<R> {
loop {
let mut event = syscall::Event::default();
if self.file.read(&mut event)? > 0 {
if let Some(ret) = self.trigger(event.id as RawFd, event.data)? {
return Ok(ret);
}
}
}
}
}