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//! Contains structs and traits relevant to the connection itself, and dispatching incoming messages.
use crate::{Error, Message, MessageType, c_str_to_slice, channel::WatchFd, ffi, to_c_str};
use crate::ffidisp::ConnPath;
use std::{fmt, mem, ptr, thread, panic, ops};
use std::{collections::VecDeque, time::Duration};
use std::cell::{Cell, RefCell};
use std::os::raw::{c_void, c_char, c_int, c_uint};
use crate::strings::{BusName, Path};
use super::{Watch, WatchList, MessageCallback, ConnectionItem, MsgHandler, MsgHandlerList, MessageReply, BusType};
/* Since we register callbacks with userdata pointers,
we need to make sure the connection pointer does not move around.
Hence this extra indirection. */
struct IConnection {
conn: Cell<*mut ffi::DBusConnection>,
pending_items: RefCell<VecDeque<Message>>,
watches: Option<Box<WatchList>>,
handlers: RefCell<super::MsgHandlerList>,
filter_cb: RefCell<Option<MessageCallback>>,
filter_cb_panic: RefCell<thread::Result<()>>,
}
/// A D-Bus connection. Start here if you want to get on the D-Bus!
pub struct Connection {
i: Box<IConnection>,
}
pub (crate) fn conn_handle(c: &Connection) -> *mut ffi::DBusConnection {
c.i.conn.get()
}
extern "C" fn filter_message_cb(conn: *mut ffi::DBusConnection, msg: *mut ffi::DBusMessage,
user_data: *mut c_void) -> ffi::DBusHandlerResult {
let i: &IConnection = unsafe { mem::transmute(user_data) };
let connref: panic::AssertUnwindSafe<&Connection> = unsafe { mem::transmute(&i) };
if i.conn.get() != conn || i.filter_cb_panic.try_borrow().is_err() {
// This should never happen, but let's be extra sure
// process::abort(); ??
return ffi::DBusHandlerResult::Handled;
}
if i.filter_cb_panic.borrow().is_err() {
// We're in panic mode. Let's quit this ASAP
return ffi::DBusHandlerResult::Handled;
}
let fcb = panic::AssertUnwindSafe(&i.filter_cb);
let r = panic::catch_unwind(|| {
let m = Message::from_ptr(msg, true);
let mut cb = fcb.borrow_mut().take().unwrap(); // Take the callback out while we call it.
let r = cb(connref.0, m);
let mut cb2 = fcb.borrow_mut(); // If the filter callback has not been replaced, put it back in.
if cb2.is_none() { *cb2 = Some(cb) };
r
});
match r {
Ok(false) => ffi::DBusHandlerResult::NotYetHandled,
Ok(true) => ffi::DBusHandlerResult::Handled,
Err(e) => {
*i.filter_cb_panic.borrow_mut() = Err(e);
ffi::DBusHandlerResult::Handled
}
}
}
fn default_filter_callback(c: &Connection, m: Message) -> bool {
let b = m.msg_type() == MessageType::Signal;
c.i.pending_items.borrow_mut().push_back(m);
b
}
extern "C" fn object_path_message_cb(_conn: *mut ffi::DBusConnection, _msg: *mut ffi::DBusMessage,
_user_data: *mut c_void) -> ffi::DBusHandlerResult {
/* Already pushed in filter_message_cb, so we just set the handled flag here to disable the
"default" handler. */
ffi::DBusHandlerResult::Handled
}
impl Connection {
#[inline(always)]
fn conn(&self) -> *mut ffi::DBusConnection {
self.i.conn.get()
}
fn conn_from_ptr(conn: *mut ffi::DBusConnection) -> Result<Connection, Error> {
let mut c = Connection { i: Box::new(IConnection {
conn: Cell::new(conn),
pending_items: RefCell::new(VecDeque::new()),
watches: None,
handlers: RefCell::new(vec!()),
filter_cb: RefCell::new(Some(Box::new(default_filter_callback))),
filter_cb_panic: RefCell::new(Ok(())),
})};
/* No, we don't want our app to suddenly quit if dbus goes down */
unsafe { ffi::dbus_connection_set_exit_on_disconnect(conn, 0) };
assert!(unsafe {
ffi::dbus_connection_add_filter(c.conn(), Some(filter_message_cb), mem::transmute(&*c.i), None)
} != 0);
c.i.watches = Some(WatchList::new(&c, Box::new(|_| {})));
Ok(c)
}
/// Creates a new connection to the session bus.
///
/// Just a shortcut for `get_private(BusType::Session)`.
pub fn new_session() -> Result<Connection, Error> { Self::get_private(BusType::Session) }
/// Creates a new connection to the system bus.
///
/// Just a shortcut for `get_private(BusType::System)`.
pub fn new_system() -> Result<Connection, Error> { Self::get_private(BusType::System) }
/// Creates a new D-Bus connection.
pub fn get_private(bus: BusType) -> Result<Connection, Error> {
let mut e = Error::empty();
let conn = unsafe { ffi::dbus_bus_get_private(bus, e.get_mut()) };
if conn.is_null() {
return Err(e)
}
Self::conn_from_ptr(conn)
}
/// Creates a new D-Bus connection to a remote address.
///
/// Note: for all common cases (System / Session bus) you probably want "get_private" instead.
pub fn open_private(address: &str) -> Result<Connection, Error> {
let mut e = Error::empty();
let conn = unsafe { ffi::dbus_connection_open_private(to_c_str(address).as_ptr(), e.get_mut()) };
if conn.is_null() {
return Err(e)
}
Self::conn_from_ptr(conn)
}
/// Registers a new D-Bus connection with the bus.
///
/// Note: `get_private` does this automatically, useful with `open_private`
pub fn register(&self) -> Result<(), Error> {
let mut e = Error::empty();
if unsafe { ffi::dbus_bus_register(self.conn(), e.get_mut()) == 0 } {
Err(e)
} else {
Ok(())
}
}
/// Gets whether the connection is currently open.
pub fn is_connected(&self) -> bool {
unsafe { ffi::dbus_connection_get_is_connected(self.conn()) != 0 }
}
/// Sends a message over the D-Bus and waits for a reply.
/// This is usually used for method calls.
pub fn send_with_reply_and_block(&self, msg: Message, timeout_ms: i32) -> Result<Message, Error> {
let mut e = Error::empty();
let response = unsafe {
ffi::dbus_connection_send_with_reply_and_block(self.conn(), msg.ptr(),
timeout_ms as c_int, e.get_mut())
};
if response.is_null() {
return Err(e);
}
Ok(Message::from_ptr(response, false))
}
/// Sends a message over the D-Bus without waiting. Useful for sending signals and method call replies.
pub fn send(&self, msg: Message) -> Result<u32,()> {
let mut serial = 0u32;
let r = unsafe { ffi::dbus_connection_send(self.conn(), msg.ptr(), &mut serial) };
if r == 0 { return Err(()); }
unsafe { ffi::dbus_connection_flush(self.conn()) };
Ok(serial)
}
/// Sends a message over the D-Bus, returning a MessageReply.
///
/// Call add_handler on the result to start waiting for reply. This should be done before next call to `incoming` or `iter`.
pub fn send_with_reply<'a, F: FnOnce(Result<&Message, Error>) + 'a>(&self, msg: Message, f: F) -> Result<MessageReply<F>, ()> {
let serial = self.send(msg)?;
Ok(MessageReply(Some(f), serial))
}
/// Adds a message handler to the connection.
///
/// # Example
///
/// ```
/// use std::{cell, rc};
/// use dbus::{ffidisp::Connection, Message};
///
/// let c = Connection::new_session().unwrap();
/// let m = Message::new_method_call("org.freedesktop.DBus", "/", "org.freedesktop.DBus", "ListNames").unwrap();
///
/// let done: rc::Rc<cell::Cell<bool>> = Default::default();
/// let done2 = done.clone();
/// c.add_handler(c.send_with_reply(m, move |reply| {
/// let v: Vec<&str> = reply.unwrap().read1().unwrap();
/// println!("The names on the D-Bus are: {:?}", v);
/// done2.set(true);
/// }).unwrap());
/// while !done.get() { c.incoming(100).next(); }
/// ```
pub fn add_handler<H: MsgHandler + 'static>(&self, h: H) {
let h = Box::new(h);
self.i.handlers.borrow_mut().push(h);
}
/// Removes a MsgHandler from the connection.
///
/// If there are many MsgHandlers, it is not specified which one will be returned.
///
/// There might be more methods added later on, which give better ways to deal
/// with the list of MsgHandler currently on the connection. If this would help you,
pub fn extract_handler(&self) -> Option<Box<dyn MsgHandler>> {
self.i.handlers.borrow_mut().pop()
}
/// Get the connection's unique name.
pub fn unique_name(&self) -> String {
let c = unsafe { ffi::dbus_bus_get_unique_name(self.conn()) };
c_str_to_slice(&c).unwrap_or("").to_string()
}
/// Check if there are new incoming events
///
/// If there are no incoming events, ConnectionItems::Nothing will be returned.
/// See ConnectionItems::new if you want to customize this behaviour.
pub fn iter(&self, timeout_ms: i32) -> ConnectionItems {
ConnectionItems::new(self, Some(timeout_ms), false)
}
/// Check if there are new incoming events
///
/// Supersedes "iter".
pub fn incoming(&self, timeout_ms: u32) -> ConnMsgs<&Self> {
ConnMsgs { conn: &self, timeout_ms: Some(timeout_ms) }
}
/// Register an object path.
pub fn register_object_path(&self, path: &str) -> Result<(), Error> {
let mut e = Error::empty();
let p = to_c_str(path);
let vtable = ffi::DBusObjectPathVTable {
unregister_function: None,
message_function: Some(object_path_message_cb),
dbus_internal_pad1: None,
dbus_internal_pad2: None,
dbus_internal_pad3: None,
dbus_internal_pad4: None,
};
let r = unsafe {
let user_data: *mut c_void = mem::transmute(&*self.i);
ffi::dbus_connection_try_register_object_path(self.conn(), p.as_ptr(), &vtable, user_data, e.get_mut())
};
if r == 0 { Err(e) } else { Ok(()) }
}
/// Unregister an object path.
pub fn unregister_object_path(&self, path: &str) {
let p = to_c_str(path);
let r = unsafe { ffi::dbus_connection_unregister_object_path(self.conn(), p.as_ptr()) };
if r == 0 { panic!("Out of memory"); }
}
/// List registered object paths.
pub fn list_registered_object_paths(&self, path: &str) -> Vec<String> {
let p = to_c_str(path);
let mut clist: *mut *mut c_char = ptr::null_mut();
let r = unsafe { ffi::dbus_connection_list_registered(self.conn(), p.as_ptr(), &mut clist) };
if r == 0 { panic!("Out of memory"); }
let mut v = Vec::new();
let mut i = 0;
loop {
let s = unsafe {
let citer = clist.offset(i);
if *citer == ptr::null_mut() { break };
mem::transmute(citer)
};
v.push(format!("{}", c_str_to_slice(s).unwrap()));
i += 1;
}
unsafe { ffi::dbus_free_string_array(clist) };
v
}
/// Register a name.
pub fn register_name(&self, name: &str, flags: u32) -> Result<super::RequestNameReply, Error> {
let mut e = Error::empty();
let n = to_c_str(name);
let r = unsafe { ffi::dbus_bus_request_name(self.conn(), n.as_ptr(), flags, e.get_mut()) };
if r == -1 { Err(e) } else { Ok(unsafe { mem::transmute(r) }) }
}
/// Release a name.
pub fn release_name(&self, name: &str) -> Result<super::ReleaseNameReply, Error> {
let mut e = Error::empty();
let n = to_c_str(name);
let r = unsafe { ffi::dbus_bus_release_name(self.conn(), n.as_ptr(), e.get_mut()) };
if r == -1 { Err(e) } else { Ok(unsafe { mem::transmute(r) }) }
}
/// Add a match rule to match messages on the message bus.
///
/// See the `unity_focused_window` example for how to use this to catch signals.
/// (The syntax of the "rule" string is specified in the [D-Bus specification](https://dbus.freedesktop.org/doc/dbus-specification.html#message-bus-routing-match-rules).)
pub fn add_match(&self, rule: &str) -> Result<(), Error> {
let mut e = Error::empty();
let n = to_c_str(rule);
unsafe { ffi::dbus_bus_add_match(self.conn(), n.as_ptr(), e.get_mut()) };
if e.name().is_some() { Err(e) } else { Ok(()) }
}
/// Remove a match rule to match messages on the message bus.
pub fn remove_match(&self, rule: &str) -> Result<(), Error> {
let mut e = Error::empty();
let n = to_c_str(rule);
unsafe { ffi::dbus_bus_remove_match(self.conn(), n.as_ptr(), e.get_mut()) };
if e.name().is_some() { Err(e) } else { Ok(()) }
}
/// Async I/O: Get an up-to-date list of file descriptors to watch.
///
/// See the `Watch` struct for an example.
pub fn watch_fds(&self) -> Vec<Watch> {
self.i.watches.as_ref().unwrap().get_enabled_fds()
}
/// Async I/O: Call this function whenever you detected an event on the Fd,
/// Flags are a set of WatchEvent bits.
/// The returned iterator will return pending items only, never block for new events.
///
/// See the `Watch` struct for an example.
pub fn watch_handle(&self, fd: WatchFd, flags: c_uint) -> ConnectionItems {
self.i.watches.as_ref().unwrap().watch_handle(fd, flags);
ConnectionItems::new(self, None, true)
}
/// Create a convenience struct for easier calling of many methods on the same destination and path.
pub fn with_path<'a, D: Into<BusName<'a>>, P: Into<Path<'a>>>(&'a self, dest: D, path: P, timeout_ms: i32) ->
ConnPath<'a, &'a Connection> {
ConnPath { conn: self, dest: dest.into(), path: path.into(), timeout: timeout_ms }
}
/// Replace the default message callback. Returns the previously set callback.
///
/// By default, when you call ConnectionItems::next, all relevant incoming messages
/// are returned through the ConnectionItems iterator, and
/// irrelevant messages are passed on to libdbus's default handler.
/// If you need to customize this behaviour (i e, to handle all incoming messages yourself),
/// you can set this message callback yourself. A few caveats apply:
///
/// Return true from the callback to disable libdbus's internal handling of the message, or
/// false to allow it. In other words, true and false correspond to
/// `DBUS_HANDLER_RESULT_HANDLED` and `DBUS_HANDLER_RESULT_NOT_YET_HANDLED` respectively.
///
/// Be sure to call the previously set callback from inside your callback,
/// if you want, e.g. ConnectionItems::next to yield the message.
///
/// You can unset the message callback (might be useful to satisfy the borrow checker), but
/// you will get a panic if you call ConnectionItems::next while the message callback is unset.
/// The message callback will be temporary unset while inside a message callback, so calling
/// ConnectionItems::next recursively will also result in a panic.
///
/// If your message callback panics, ConnectionItems::next will panic, too.
///
/// # Examples
///
/// Replace the default callback with our own:
///
/// ```ignore
/// use dbus::ffidisp::Connection;
/// let c = Connection::new_session().unwrap();
/// // Set our callback
/// c.replace_message_callback(Some(Box::new(move |conn, msg| {
/// println!("Got message: {:?}", msg.get_items());
/// // Let libdbus handle some things by default,
/// // like "nonexistent object" error replies to method calls
/// false
/// })));
///
/// for _ in c.iter(1000) {
/// // Only `ConnectionItem::Nothing` would be ever yielded here.
/// }
/// ```
///
/// Chain our callback to filter out some messages before `iter().next()`:
///
/// ```
/// use dbus::{ffidisp::Connection, MessageType};
/// let c = Connection::new_session().unwrap();
/// // Take the previously set callback
/// let mut old_cb = c.replace_message_callback(None).unwrap();
/// // Set our callback
/// c.replace_message_callback(Some(Box::new(move |conn, msg| {
/// // Handle all signals on the spot
/// if msg.msg_type() == MessageType::Signal {
/// println!("Got signal: {:?}", msg.get_items());
/// // Stop all further processing of the message
/// return true;
/// }
/// // Delegate the rest of the messages to the previous callback
/// // in chain, e.g. to have them yielded by `iter().next()`
/// old_cb(conn, msg)
/// })));
///
/// # if false {
/// for _ in c.iter(1000) {
/// // `ConnectionItem::Signal` would never be yielded here.
/// }
/// # }
/// ```
pub fn replace_message_callback(&self, f: Option<MessageCallback>) -> Option<MessageCallback> {
mem::replace(&mut *self.i.filter_cb.borrow_mut(), f)
}
/// Sets a callback to be called if a file descriptor status changes.
///
/// For async I/O. In rare cases, the number of fds to poll for read/write can change.
/// If this ever happens, you'll get a callback. The watch changed is provided as a parameter.
///
/// In rare cases this might not even happen in the thread calling anything on the connection,
/// so the callback needs to be `Send`.
/// A mutex is held during the callback. If you try to call set_watch_callback from a callback,
/// you will deadlock.
///
/// (Previously, this was instead put in a ConnectionItem queue, but this was not working correctly.
pub fn set_watch_callback(&self, f: Box<dyn Fn(Watch) + Send>) { self.i.watches.as_ref().unwrap().set_on_update(f); }
fn check_panic(&self) {
let p = mem::replace(&mut *self.i.filter_cb_panic.borrow_mut(), Ok(()));
if let Err(perr) = p { panic::resume_unwind(perr); }
}
fn next_msg(&self) -> Option<Message> {
while let Some(msg) = self.i.pending_items.borrow_mut().pop_front() {
let mut v: MsgHandlerList = mem::replace(&mut *self.i.handlers.borrow_mut(), vec!());
let b = msghandler_process(&mut v, &msg, self);
let mut v2 = self.i.handlers.borrow_mut();
v.append(&mut *v2);
*v2 = v;
if !b { return Some(msg) };
};
None
}
}
impl Drop for Connection {
fn drop(&mut self) {
unsafe {
ffi::dbus_connection_close(self.conn());
ffi::dbus_connection_unref(self.conn());
}
}
}
impl fmt::Debug for Connection {
fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
write!(f, "D-Bus Connection({})", self.unique_name())
}
}
impl crate::channel::Sender for Connection {
fn send(&self, msg: Message) -> Result<u32, ()> { Connection::send(self, msg) }
}
impl crate::blocking::BlockingSender for Connection {
fn send_with_reply_and_block(&self, msg: Message, timeout: Duration) -> Result<Message, Error> {
Connection::send_with_reply_and_block(self, msg, timeout.as_millis() as i32)
}
}
fn msghandler_process(v: &mut MsgHandlerList, m: &Message, c: &Connection) -> bool {
let mut ii: isize = -1;
loop {
ii += 1;
let i = ii as usize;
if i >= v.len() { return false };
if !v[i].handler_type().matches_msg(m) { continue; }
if let Some(r) = v[i].handle_msg(m) {
for msg in r.reply.into_iter() { c.send(msg).unwrap(); }
if r.done { v.remove(i); ii -= 1; }
if r.handled { return true; }
}
}
}
/// ConnectionItem iterator
pub struct ConnectionItems<'a> {
c: &'a Connection,
timeout_ms: Option<i32>,
end_on_timeout: bool,
handlers: MsgHandlerList,
}
impl<'a> ConnectionItems<'a> {
/// Builder method that adds a new msg handler.
///
/// Note: Likely to changed/refactored/removed in next release
pub fn with<H: 'static + MsgHandler>(mut self, h: H) -> Self {
self.handlers.push(Box::new(h)); self
}
// Returns true if processed, false if not
fn process_handlers(&mut self, ci: &ConnectionItem) -> bool {
let m = match *ci {
ConnectionItem::MethodReturn(ref msg) => msg,
ConnectionItem::Signal(ref msg) => msg,
ConnectionItem::MethodCall(ref msg) => msg,
ConnectionItem::Nothing => return false,
};
msghandler_process(&mut self.handlers, m, &self.c)
}
/// Access and modify message handlers
///
/// Note: Likely to changed/refactored/removed in next release
pub fn msg_handlers(&mut self) -> &mut Vec<Box<dyn MsgHandler>> { &mut self.handlers }
/// Creates a new ConnectionItems iterator
///
/// For io_timeout, setting None means the fds will not be read/written. I e, only pending
/// items in libdbus's internal queue will be processed.
///
/// For end_on_timeout, setting false will means that the iterator will never finish (unless
/// the D-Bus server goes down). Instead, ConnectionItem::Nothing will be returned in case no
/// items are in queue.
pub fn new(conn: &'a Connection, io_timeout: Option<i32>, end_on_timeout: bool) -> Self {
ConnectionItems {
c: conn,
timeout_ms: io_timeout,
end_on_timeout: end_on_timeout,
handlers: Vec::new(),
}
}
}
impl<'a> Iterator for ConnectionItems<'a> {
type Item = ConnectionItem;
fn next(&mut self) -> Option<ConnectionItem> {
loop {
if self.c.i.filter_cb.borrow().is_none() { panic!("ConnectionItems::next called recursively or with a MessageCallback set to None"); }
let i: Option<ConnectionItem> = self.c.next_msg().map(|x| x.into());
if let Some(ci) = i {
if !self.process_handlers(&ci) { return Some(ci); }
}
if let Some(t) = self.timeout_ms {
let r = unsafe { ffi::dbus_connection_read_write_dispatch(self.c.conn(), t as c_int) };
self.c.check_panic();
if !self.c.i.pending_items.borrow().is_empty() { continue };
if r == 0 { return None; }
}
let r = unsafe { ffi::dbus_connection_dispatch(self.c.conn()) };
self.c.check_panic();
if !self.c.i.pending_items.borrow().is_empty() { continue };
if r == ffi::DBusDispatchStatus::DataRemains { continue };
if r == ffi::DBusDispatchStatus::Complete { return if self.end_on_timeout { None } else { Some(ConnectionItem::Nothing) } };
panic!("dbus_connection_dispatch failed");
}
}
}
/// Iterator over incoming messages on a connection.
#[derive(Debug, Clone)]
pub struct ConnMsgs<C> {
/// The connection or some reference to it.
pub conn: C,
/// How many ms dbus should block, waiting for incoming messages until timing out.
///
/// If set to None, the dbus library will not read/write from file descriptors at all.
/// Instead the iterator will end when there's nothing currently in the queue.
pub timeout_ms: Option<u32>,
}
impl<C: ops::Deref<Target = Connection>> Iterator for ConnMsgs<C> {
type Item = Message;
fn next(&mut self) -> Option<Self::Item> {
loop {
let iconn = &self.conn.i;
if iconn.filter_cb.borrow().is_none() { panic!("ConnMsgs::next called recursively or with a MessageCallback set to None"); }
let i = self.conn.next_msg();
if let Some(ci) = i { return Some(ci); }
if let Some(t) = self.timeout_ms {
let r = unsafe { ffi::dbus_connection_read_write_dispatch(self.conn.conn(), t as c_int) };
self.conn.check_panic();
if !iconn.pending_items.borrow().is_empty() { continue };
if r == 0 { return None; }
}
let r = unsafe { ffi::dbus_connection_dispatch(self.conn.conn()) };
self.conn.check_panic();
if !iconn.pending_items.borrow().is_empty() { continue };
if r == ffi::DBusDispatchStatus::DataRemains { continue };
if r == ffi::DBusDispatchStatus::Complete { return None }
panic!("dbus_connection_dispatch failed");
}
}
}
#[test]
fn message_reply() {
use std::{cell, rc};
let c = Connection::get_private(BusType::Session).unwrap();
assert!(c.is_connected());
let m = Message::new_method_call("org.freedesktop.DBus", "/", "org.freedesktop.DBus", "ListNames").unwrap();
let quit = rc::Rc::new(cell::Cell::new(false));
let quit2 = quit.clone();
let reply = c.send_with_reply(m, move |result| {
let r = result.unwrap();
let _: crate::arg::Array<&str, _> = r.get1().unwrap();
quit2.set(true);
}).unwrap();
for _ in c.iter(1000).with(reply) { if quit.get() { return; } }
assert!(false);
}