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Merge pull request #248 from rtbo/poll_for_reply
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Add `poll_for_reply` and `poll_for_reply_unchecked` functions
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@rtbo
rtbo authored Dec 9, 2023
2 parents c5411cd + 325691b commit 21efad1
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Showing 2 changed files with 245 additions and 45 deletions.
286 changes: 243 additions & 43 deletions src/base.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -16,7 +16,7 @@ use bitflags::bitflags;
use libc::{c_char, c_int};

use std::cell::RefCell;
use std::ffi::{CStr, CString};
use std::ffi::{c_void, CStr, CString};
use std::fmt::{self, Display, Formatter};
use std::marker::{self, PhantomData};
use std::mem;
Expand Down Expand Up @@ -1162,17 +1162,6 @@ impl Connection {
}
}

unsafe fn handle_wait_for_event(&self, ev: *mut xcb_generic_event_t) -> Result<Event> {
if ev.is_null() {
self.has_error()?;
panic!("xcb_wait_for_event returned null with I/O error");
} else if is_error(ev) {
Err(error::resolve_error(ev as *mut _, &self.ext_data).into())
} else {
Ok(event::resolve_event(ev, &self.ext_data))
}
}

/// Resolve an xcb_generic_event_t pointer into an Event.
/// # Safety
/// The caller is repsonsible to ensure that the `ev` pointer is not NULL.
Expand All @@ -1183,17 +1172,6 @@ impl Connection {
event::resolve_event(ev, &self.ext_data)
}

unsafe fn handle_poll_for_event(&self, ev: *mut xcb_generic_event_t) -> Result<Option<Event>> {
if ev.is_null() {
self.has_error()?;
Ok(None)
} else if is_error(ev) {
Err(error::resolve_error(ev as *mut _, &self.ext_data).into())
} else {
Ok(Some(event::resolve_event(ev, &self.ext_data)))
}
}

/// Blocks and returns the next event or error from the server.
///
/// # Example
Expand Down Expand Up @@ -1533,7 +1511,10 @@ impl Connection {
self.check_request(self.send_request_checked(req))
}

/// Get the reply of a previous request, or an error if one occured.
/// Gets the reply of a previous request, or an error if one occurred.
///
/// This is blocking; it does not return until the reply has been received. For the non-blocking
/// version, see [`poll_for_reply`].
///
/// # Example
/// ```no_run
Expand All @@ -1550,31 +1531,25 @@ impl Connection {
/// # Ok(())
/// # }
/// ```
///
/// [`poll_for_reply`]: Self::poll_for_reply
pub fn wait_for_reply<C>(&self, cookie: C) -> Result<C::Reply>
where
C: CookieWithReplyChecked,
{
unsafe {
let mut error: *mut xcb_generic_error_t = std::ptr::null_mut();
let mut error: *mut xcb_generic_error_t = ptr::null_mut();
let reply = xcb_wait_for_reply64(self.c, cookie.sequence(), &mut error as *mut _);
match (reply.is_null(), error.is_null()) {
(true, true) => {
self.has_error()?;
unreachable!("xcb_wait_for_reply64 returned null without I/O error");
}
(true, false) => {
let error = error::resolve_error(error, &self.ext_data);
Err(error.into())
}
(false, true) => Ok(C::Reply::from_raw(reply as *const u8)),
(false, false) => unreachable!("xcb_wait_for_reply64 returned two pointers"),
}
self.handle_reply_checked::<C>(reply, error)
}
}

/// Get the reply of a previous unchecked request.
///
/// If an error occured, `None` is returned and the error will be delivered to the event loop.
/// If an error occurred, `None` is returned and the error will be delivered to the event loop.
///
/// This is blocking; it does not return until the reply has been received. For the non-blocking
/// version, see [`poll_for_reply_unchecked`].
///
/// # Example
/// ```no_run
Expand All @@ -1591,17 +1566,184 @@ impl Connection {
/// # Ok(())
/// # }
/// ```
///
/// [`poll_for_reply_unchecked`]: Self::poll_for_reply_unchecked
pub fn wait_for_reply_unchecked<C>(&self, cookie: C) -> ConnResult<Option<C::Reply>>
where
C: CookieWithReplyUnchecked,
{
unsafe {
let reply = xcb_wait_for_reply64(self.c, cookie.sequence(), ptr::null_mut());
if reply.is_null() {
self.has_error()?;
Ok(None)
} else {
Ok(Some(C::Reply::from_raw(reply as *const u8)))
self.handle_reply_unchecked::<C>(reply)
}
}

/// Gets the reply of a previous request if it has been received, or an error if one occurred.
///
/// This is non-blocking; if no reply has been received yet, it returns [`None`]. For the
/// blocking version, see [`wait_for_reply`].
///
/// # Examples
/// ```no_run
/// # use xcb::x;
/// # fn main() -> xcb::Result<()> {
/// # let (conn, screen_num) = xcb::Connection::connect(None)?;
/// let (wm_protocols_cookie, wm_name_cookie) = (
/// conn.send_request(&x::InternAtom {
/// only_if_exists: true,
/// name: b"WM_PROTOCOLS",
/// }),
/// conn.send_request(&x::InternAtom {
/// only_if_exists: true,
/// name: b"WM_NAME",
/// }),
/// );
/// let (wm_protocols_atom, wm_name_atom) = {
/// let (
/// mut wm_protocols_atom,
/// mut wm_name_atom,
/// ) = (None, None);
///
/// loop {
/// // If `wm_protocols_atom` is yet to be received, poll for it.
/// if wm_protocols_atom.is_none() {
/// wm_protocols_atom = conn
/// .poll_for_reply(&wm_protocols_cookie)
/// .transpose()?
/// .map(|reply| reply.atom());
/// }
/// // If `wm_name_atom` is yet to be received, poll for it.
/// if wm_name_atom.is_none() {
/// wm_name_atom = conn
/// .poll_for_reply(&wm_name_cookie)
/// .transpose()?
/// .map(|reply| reply.atom());
/// }
///
/// // If both `wm_protocols_atom` and `wm_name_atom` have been
/// // received, break from the loop.
/// if let (
/// Some(wm_protocols_atom),
/// Some(wm_name_atom),
/// ) = (wm_protocols_atom, wm_name_atom) {
/// break (wm_protocols_atom, wm_name_atom);
/// }
/// }
/// };
/// # Ok(())
/// # }
/// ```
///
/// [`wait_for_reply`]: Self::wait_for_reply
pub fn poll_for_reply<C>(&self, cookie: &C) -> Option<Result<C::Reply>>
where
C: CookieWithReplyChecked,
{
unsafe {
let mut error: *mut xcb_generic_error_t = ptr::null_mut();
let mut reply: *mut c_void = ptr::null_mut();

let received = xcb_poll_for_reply64(
self.c,
cookie.sequence(),
&mut reply as *mut _,
&mut error as *mut _,
);

match received {
0 => None,
1 => Some(self.handle_reply_checked::<C>(reply, error)),
_ => panic!("unexpected return value from xcb_poll_for_reply64"),
}
}
}

/// Gets the reply of a previous unchecked request if it has been received.
///
/// If an error occurred, [`None`] is returned and the error is delivered to the event loop.
///
/// This is non-blocking; if no reply has been received yet, it returns
/// <code>[Some]\([None])</code>. For the blocking version, see [`wait_for_reply_unchecked`].
///
/// # Examples
/// ```no_run
/// # use xcb::x;
/// # fn main() -> xcb::Result<()> {
/// # let (conn, screen_num) = xcb::Connection::connect(None)?;
/// let (wm_protocols_cookie, wm_name_cookie) = (
/// conn.send_request_unchecked(&x::InternAtom {
/// only_if_exists: true,
/// name: b"WM_PROTOCOLS",
/// }),
/// conn.send_request_unchecked(&x::InternAtom {
/// only_if_exists: true,
/// name: b"WM_NAME",
/// }),
/// );
/// let (wm_protocols_atom, wm_name_atom) = {
/// let (
/// mut wm_protocols_atom,
/// mut wm_name_atom,
/// ) = (Some(None), Some(None));
///
/// loop {
/// // If `wm_protocols_atom` is yet to be received, poll for it.
/// if let Some(None) = wm_protocols_atom {
/// wm_protocols_atom = conn
/// // connection error may happen
/// .poll_for_reply_unchecked(&wm_protocols_cookie)
/// .transpose()?
/// .map(|result| result.map(|reply| reply.atom()));
/// }
/// // If `wm_name_atom` is yet to be received, poll for it.
/// if let Some(None) = wm_name_atom {
/// wm_name_atom = conn
/// // connection error may happen
/// .poll_for_reply_unchecked(&wm_name_cookie)
/// .transpose()?
/// .map(|result| result.map(|reply| reply.atom()));
/// }
///
/// match (wm_protocols_atom, wm_name_atom) {
/// // If either `wm_protocols_atom` or `wm_name_atom` hasn't
/// // been received, continue the loop.
/// (Some(None), _) | (_, Some(None)) => continue,
///
/// // Otherwise, if both have been received, break from the
/// // loop.
/// (
/// wm_protocols_atom,
/// wm_name_atom,
/// ) => break (
/// wm_protocols_atom.flatten(),
/// wm_name_atom.flatten(),
/// ),
/// }
/// }
/// };
/// # Ok(())
/// # }
/// ```
///
/// [`wait_for_reply_unchecked`]: Self::wait_for_reply_unchecked
pub fn poll_for_reply_unchecked<C>(&self, cookie: &C) -> Option<ConnResult<Option<C::Reply>>>
where
C: CookieWithReplyUnchecked,
{
unsafe {
let mut reply: *mut c_void = ptr::null_mut();

let received = xcb_poll_for_reply64(
self.c,
cookie.sequence(),
&mut reply as *mut _,
ptr::null_mut(),
);

match received {
0 => None,
1 => Some(self.handle_reply_unchecked::<C>(reply)),
_ => panic!("unexpected return value from xcb_poll_for_reply64"),
}
}
}
Expand All @@ -1627,6 +1769,64 @@ impl Connection {
}
}

impl Connection {
unsafe fn handle_wait_for_event(&self, ev: *mut xcb_generic_event_t) -> Result<Event> {
if ev.is_null() {
self.has_error()?;
panic!("xcb_wait_for_event returned null with I/O error");
} else if is_error(ev) {
Err(error::resolve_error(ev as *mut _, &self.ext_data).into())
} else {
Ok(event::resolve_event(ev, &self.ext_data))
}
}

unsafe fn handle_poll_for_event(&self, ev: *mut xcb_generic_event_t) -> Result<Option<Event>> {
if ev.is_null() {
self.has_error()?;
Ok(None)
} else if is_error(ev) {
Err(error::resolve_error(ev as *mut _, &self.ext_data).into())
} else {
Ok(Some(event::resolve_event(ev, &self.ext_data)))
}
}

unsafe fn handle_reply_checked<C>(
&self,
reply: *mut c_void,
error: *mut xcb_generic_error_t,
) -> Result<C::Reply>
where
C: CookieWithReplyChecked,
{
match (reply.is_null(), error.is_null()) {
(true, true) => {
self.has_error()?;
unreachable!("xcb_wait_for_reply64 returned null without I/O error");
}
(true, false) => {
let error = error::resolve_error(error, &self.ext_data);
Err(error.into())
}
(false, true) => Ok(C::Reply::from_raw(reply as *const u8)),
(false, false) => unreachable!("xcb_wait_for_reply64 returned two pointers"),
}
}

unsafe fn handle_reply_unchecked<C>(&self, reply: *mut c_void) -> ConnResult<Option<C::Reply>>
where
C: CookieWithReplyUnchecked,
{
if reply.is_null() {
self.has_error()?;
Ok(None)
} else {
Ok(Some(C::Reply::from_raw(reply as *const u8)))
}
}
}

impl AsRef<Connection> for Connection {
fn as_ref(&self) -> &Connection {
self
Expand Down
4 changes: 2 additions & 2 deletions src/ffi/ext.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -238,14 +238,14 @@ extern "C" {
request: c_uint,
reply: *mut *mut c_void,
e: *mut *mut xcb_generic_error_t,
) -> *mut c_void;
) -> c_int;

pub(crate) fn xcb_poll_for_reply64(
c: *mut xcb_connection_t,
request: u64,
reply: *mut *mut c_void,
e: *mut *mut xcb_generic_error_t,
) -> *mut c_void;
) -> c_int;

/**
* @brief Don't use this, only needed by the generated code.
Expand Down

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