Source code
Revision control
Copy as Markdown
Other Tools
use ffi;
use libc;
use super::Connection;
use std::mem;
use std::sync::{Mutex, RwLock};
use std::os::unix::io::{RawFd, AsRawFd};
use std::os::raw::{c_void, c_uint};
/// A file descriptor to watch for incoming events (for async I/O).
///
/// # Example
/// ```
/// extern crate libc;
/// extern crate dbus;
/// fn main() {
/// use dbus::{Connection, BusType, WatchEvent};
/// let c = Connection::get_private(BusType::Session).unwrap();
///
/// // Get a list of fds to poll for
/// let mut fds: Vec<_> = c.watch_fds().iter().map(|w| w.to_pollfd()).collect();
///
/// // Poll them with a 1 s timeout
/// let r = unsafe { libc::poll(fds.as_mut_ptr(), fds.len() as libc::c_ulong, 1000) };
/// assert!(r >= 0);
///
/// // And handle incoming events
/// for pfd in fds.iter().filter(|pfd| pfd.revents != 0) {
/// for item in c.watch_handle(pfd.fd, WatchEvent::from_revents(pfd.revents)) {
/// // Handle item
/// println!("Received ConnectionItem: {:?}", item);
/// }
/// }
/// }
/// ```
#[repr(C)]
#[derive(Debug, PartialEq, Copy, Clone)]
/// The enum is here for backwards compatibility mostly.
///
/// It should really be bitflags instead.
pub enum WatchEvent {
/// The fd is readable
Readable = ffi::DBUS_WATCH_READABLE as isize,
/// The fd is writable
Writable = ffi::DBUS_WATCH_WRITABLE as isize,
/// An error occured on the fd
Error = ffi::DBUS_WATCH_ERROR as isize,
/// The fd received a hangup.
Hangup = ffi::DBUS_WATCH_HANGUP as isize,
}
impl WatchEvent {
/// After running poll, this transforms the revents into a parameter you can send into `Connection::watch_handle`
pub fn from_revents(revents: libc::c_short) -> c_uint {
0 +
if (revents & libc::POLLIN) != 0 { WatchEvent::Readable as c_uint } else { 0 } +
if (revents & libc::POLLOUT) != 0 { WatchEvent::Writable as c_uint } else { 0 } +
if (revents & libc::POLLERR) != 0 { WatchEvent::Error as c_uint } else { 0 } +
if (revents & libc::POLLHUP) != 0 { WatchEvent::Hangup as c_uint } else { 0 }
}
}
#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord)]
/// A file descriptor, and an indication whether it should be read from, written to, or both.
pub struct Watch {
fd: RawFd,
read: bool,
write: bool,
}
impl Watch {
/// Get the RawFd this Watch is for
pub fn fd(&self) -> RawFd { self.fd }
/// Add POLLIN to events to listen for
pub fn readable(&self) -> bool { self.read }
/// Add POLLOUT to events to listen for
pub fn writable(&self) -> bool { self.write }
/// Returns the current watch as a libc::pollfd, to use with libc::poll
pub fn to_pollfd(&self) -> libc::pollfd {
libc::pollfd { fd: self.fd, revents: 0, events: libc::POLLERR + libc::POLLHUP +
if self.readable() { libc::POLLIN } else { 0 } +
if self.writable() { libc::POLLOUT } else { 0 },
}
}
/*
pub (crate) unsafe fn from_raw(watch: *mut ffi::DBusWatch) -> Self {
let mut w = Watch { fd: ffi::dbus_watch_get_unix_fd(watch), read: false, write: false};
let enabled = ffi::dbus_watch_get_enabled(watch) != 0;
if enabled {
let flags = ffi::dbus_watch_get_flags(watch);
w.read = (flags & WatchEvent::Readable as c_uint) != 0;
w.write = (flags & WatchEvent::Writable as c_uint) != 0;
}
w
}
*/
}
impl AsRawFd for Watch {
fn as_raw_fd(&self) -> RawFd { self.fd }
}
/// Note - internal struct, not to be used outside API. Moving it outside its box will break things.
pub struct WatchList {
watches: RwLock<Vec<*mut ffi::DBusWatch>>,
enabled_fds: Mutex<Vec<Watch>>,
on_update: Mutex<Box<Fn(Watch) + Send>>,
}
impl WatchList {
pub fn new(c: &Connection, on_update: Box<Fn(Watch) + Send>) -> Box<WatchList> {
let w = Box::new(WatchList { on_update: Mutex::new(on_update), watches: RwLock::new(vec!()), enabled_fds: Mutex::new(vec!()) });
if unsafe { ffi::dbus_connection_set_watch_functions(super::connection::conn_handle(c),
Some(add_watch_cb), Some(remove_watch_cb), Some(toggled_watch_cb), &*w as *const _ as *mut _, None) } == 0 {
panic!("dbus_connection_set_watch_functions failed");
}
w
}
pub fn set_on_update(&self, on_update: Box<Fn(Watch) + Send>) { *self.on_update.lock().unwrap() = on_update; }
pub fn watch_handle(&self, fd: RawFd, flags: c_uint) {
// println!("watch_handle {} flags {}", fd, flags);
for &q in self.watches.read().unwrap().iter() {
let w = self.get_watch(q);
if w.fd != fd { continue };
if unsafe { ffi::dbus_watch_handle(q, flags) } == 0 {
panic!("dbus_watch_handle failed");
}
self.update(q);
};
}
pub fn get_enabled_fds(&self) -> Vec<Watch> {
self.enabled_fds.lock().unwrap().clone()
}
fn get_watch(&self, watch: *mut ffi::DBusWatch) -> Watch {
let mut w = Watch { fd: unsafe { ffi::dbus_watch_get_unix_fd(watch) }, read: false, write: false};
let enabled = self.watches.read().unwrap().contains(&watch) && unsafe { ffi::dbus_watch_get_enabled(watch) != 0 };
let flags = unsafe { ffi::dbus_watch_get_flags(watch) };
if enabled {
w.read = (flags & WatchEvent::Readable as c_uint) != 0;
w.write = (flags & WatchEvent::Writable as c_uint) != 0;
}
// println!("Get watch fd {:?} ptr {:?} enabled {:?} flags {:?}", w, watch, enabled, flags);
w
}
fn update(&self, watch: *mut ffi::DBusWatch) {
let mut w = self.get_watch(watch);
for &q in self.watches.read().unwrap().iter() {
if q == watch { continue };
let ww = self.get_watch(q);
if ww.fd != w.fd { continue };
w.read |= ww.read;
w.write |= ww.write;
}
// println!("Updated sum: {:?}", w);
{
let mut fdarr = self.enabled_fds.lock().unwrap();
if w.write || w.read {
if fdarr.contains(&w) { return; } // Nothing changed
}
else if !fdarr.iter().any(|q| w.fd == q.fd) { return; } // Nothing changed
fdarr.retain(|f| f.fd != w.fd);
if w.write || w.read { fdarr.push(w) };
}
let func = self.on_update.lock().unwrap();
(*func)(w);
}
}
extern "C" fn add_watch_cb(watch: *mut ffi::DBusWatch, data: *mut c_void) -> u32 {
let wlist: &WatchList = unsafe { mem::transmute(data) };
// println!("Add watch {:?}", watch);
wlist.watches.write().unwrap().push(watch);
wlist.update(watch);
1
}
extern "C" fn remove_watch_cb(watch: *mut ffi::DBusWatch, data: *mut c_void) {
let wlist: &WatchList = unsafe { mem::transmute(data) };
// println!("Removed watch {:?}", watch);
wlist.watches.write().unwrap().retain(|w| *w != watch);
wlist.update(watch);
}
extern "C" fn toggled_watch_cb(watch: *mut ffi::DBusWatch, data: *mut c_void) {
let wlist: &WatchList = unsafe { mem::transmute(data) };
// println!("Toggled watch {:?}", watch);
wlist.update(watch);
}
#[cfg(test)]
mod test {
use libc;
use super::super::{Connection, Message, BusType, WatchEvent, ConnectionItem, MessageType};
#[test]
fn async() {
let c = Connection::get_private(BusType::Session).unwrap();
c.register_object_path("/test").unwrap();
let m = Message::new_method_call(&c.unique_name(), "/test", "com.example.asynctest", "AsyncTest").unwrap();
let serial = c.send(m).unwrap();
println!("Async: sent serial {}", serial);
let mut fds: Vec<_> = c.watch_fds().iter().map(|w| w.to_pollfd()).collect();
let mut new_fds = None;
let mut i = 0;
let mut success = false;
while !success {
i += 1;
if let Some(q) = new_fds { fds = q; new_fds = None };
for f in fds.iter_mut() { f.revents = 0 };
assert!(unsafe { libc::poll(fds.as_mut_ptr(), fds.len() as libc::nfds_t, 1000) } > 0);
for f in fds.iter().filter(|pfd| pfd.revents != 0) {
let m = WatchEvent::from_revents(f.revents);
println!("Async: fd {}, revents {} -> {}", f.fd, f.revents, m);
assert!(f.revents & libc::POLLIN != 0 || f.revents & libc::POLLOUT != 0);
for e in c.watch_handle(f.fd, m) {
println!("Async: got {:?}", e);
match e {
ConnectionItem::MethodCall(m) => {
assert_eq!(m.headers(), (MessageType::MethodCall, Some("/test".to_string()),
Some("com.example.asynctest".into()), Some("AsyncTest".to_string())));
let mut mr = Message::new_method_return(&m).unwrap();
mr.append_items(&["Goodies".into()]);
c.send(mr).unwrap();
}
ConnectionItem::MethodReturn(m) => {
assert_eq!(m.headers().0, MessageType::MethodReturn);
assert_eq!(m.get_reply_serial().unwrap(), serial);
let i = m.get_items();
let s: &str = i[0].inner().unwrap();
assert_eq!(s, "Goodies");
success = true;
}
_ => (),
}
}
if i > 100 { panic!() };
}
}
}
}