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extern crate libc;
use super::daemon::*;
use std::io::{Error, ErrorKind};
use std::sync::mpsc::channel;
use std::sync::mpsc::Receiver;
use std::sync::mpsc::Sender;
declare_singleton! (singleton, DaemonHolder, DaemonHolder {holder: 0 as *mut DaemonStatic});
struct DaemonHolder {
holder: *mut DaemonStatic,
}
struct DaemonStatic
{
holder: Box<DaemonFunc>,
}
trait DaemonFunc
{
fn exec(&mut self) -> Result<(), Error>;
fn send(&mut self, state: State) -> Result<(), Error>;
fn take_tx(&mut self) -> Option<Sender<State>>;
}
struct DaemonFuncHolder <F: FnOnce(Receiver<State>)>
{
tx: Option<Sender<State>>,
func: Option<(F, Receiver<State>)>,
}
impl <F: FnOnce(Receiver<State>)> DaemonFunc for DaemonFuncHolder<F>
{
fn exec(&mut self) -> Result<(), Error>
{
match self.func.take()
{
Some((func, rx)) => {
func(rx);
Ok(())
}
None => Err(Error::new(ErrorKind::Other, "INTERNAL ERROR: Can't unwrap daemon function"))
}
}
fn send(&mut self, state: State) -> Result<(), Error>
{
match self.tx
{
Some(ref tx) => match tx.send(state)
{
Ok(_) => Ok(()),
Err(e) => Err(Error::new(ErrorKind::Other, e)),
},
None => Err(Error::new(ErrorKind::Other, "Service is already exited")),
}
}
fn take_tx(&mut self) -> Option<Sender<State>>
{
self.tx.take()
}
}
fn daemon_wrapper<R, F: FnOnce(&mut DaemonHolder) -> R>(func: F) -> R {
let singleton = singleton();
let result = match singleton.lock() {
Ok(ref mut daemon) => {
func(daemon)
}
Err(e) => {
panic!("Mutex error: {:?}", e);
}
};
result
}
impl DaemonRunner for Daemon
{
fn run<F: 'static + FnOnce(Receiver<State>)>(&self, func: F) -> Result<(), Error> {
let (tx, rx) = channel();
tx.send(State::Start).unwrap();
let mut daemon = DaemonStatic
{
holder: Box::new(DaemonFuncHolder
{
tx: Some(tx),
func: Some((func, rx)),
}),
};
try! (guard_compare_and_swap(daemon_null(), &mut daemon));
let result = daemon_console(&mut daemon);
try! (guard_compare_and_swap(&mut daemon, daemon_null()));
result
}
}
fn guard_compare_and_swap(old_value: *mut DaemonStatic, new_value: *mut DaemonStatic) -> Result<(), Error>
{
daemon_wrapper(|daemon_static: &mut DaemonHolder| -> Result<(), Error> {
if daemon_static.holder != old_value
{
return Err(Error::new(ErrorKind::Other, "This function is not reentrant."));
}
daemon_static.holder = new_value;
Ok(())
})
}
fn daemon_console(daemon: &mut DaemonStatic) -> Result<(), Error>
{
let result;
unsafe
{
result = daemon.holder.exec();
}
result
}
unsafe extern "system" fn signal_handler(sig: libc::c_int)
{
daemon_wrapper(|daemon_static: &mut DaemonHolder| {
let daemon = &mut *daemon_static.holder;
return match daemon.holder.take_tx()
{
Some(ref tx) => {
let _ = tx.send(State::Stop);
}
None => ()
}
});
}
fn daemon_null() -> *mut DaemonStatic {
0 as *mut DaemonStatic
}
extern "C" {
fn raise(sig: libc::c_int) -> libc::c_int;
fn signal(sig: libc::c_int, handler: *const libc::c_void) -> libc::c_int;
fn kill(pid: libc::pid_t, sig: libc::c_int) -> libc::c_int;
}