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feat: send huge Wayland-to-X selections via INCR

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Since the connection handshake establishes the most data a request can
send, if the data length exceeds that limit, we can follow ICCCM 2.7.2
sending the INCR property and continuing to send data via PropertyNotify
events.

To test the changes, we create `XState::set_max_req_bytes` to forcefully
trigger the INCR mechanism in integration test runs with a constant,
substantially less amount of data.
This commit is contained in:
En-En 2025-09-28 00:41:31 +00:00 • committed by Supreeeme
parent 334933b212
commit 1ec45141e6
4 changed files with 254 additions and 81 deletions
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24
src/xstate/mod.rs
View file

@ -119,6 +119,7 @@ pub struct XState {
wm_window: x::Window,
selection_state: SelectionState,
settings: Settings,
max_req_bytes: usize,
}
impl XState {
@ -226,6 +227,9 @@ impl XState {
let selection_state = SelectionState::new(&connection, root, &atoms);
let window_atoms = WindowTypes::intern_all(&connection).unwrap();
let settings = Settings::new(&connection, &atoms, root);
// maximum-request-length is returned in units of 4 bytes.
// Additionally, requests use 32 bytes of metadata which cannot store arbitrary data
let max_req_bytes = (connection.get_maximum_request_length() * 4 - 32) as usize;
let mut r = Self {
connection,
@ -235,12 +239,21 @@ impl XState {
window_atoms,
selection_state,
settings,
max_req_bytes,
};
r.create_ewmh_window();
r.set_xsettings_owner();
r
}
pub(super) fn set_max_req_bytes(&mut self, max_req_bytes: usize) {
// `max_req_bytes` is initialized to the largest possible value before transfer problems
// would begin to occur. This function is called once during initialization only in
// integration tests, so this overly simple check is fine.
assert!(self.max_req_bytes >= max_req_bytes);
self.max_req_bytes = max_req_bytes;
}
pub fn server_state_setup(
&self,
server_state: super::EarlyServerState,
@ -883,9 +896,12 @@ impl XState {
event: x::PropertyNotifyEvent,
server_state: &mut super::RealServerState,
) {
if event.state() != x::Property::NewValue {
if self.handle_selection_property_change(&event) {
return;
}
if event.state() == x::Property::Delete {
debug!(
"ignoring non newvalue for property {:?}",
"ignoring delete for property {:?}",
get_atom_name(&self.connection, event.atom())
);
return;
@ -929,9 +945,7 @@ impl XState {
}
}
_ => {
if !self.handle_selection_property_change(&event)
&& log::log_enabled!(log::Level::Debug)
{
if log::log_enabled!(log::Level::Debug) {
debug!(
"changed property {:?} for {:?}",
get_atom_name(&self.connection, event.atom()),

177
src/xstate/selection.rs
View file

@ -162,12 +162,59 @@ impl Selection {
}
}
pub struct WaylandIncrInfo {
data: Vec<u8>,
range: std::ops::Range<usize>,
property: x::Atom,
target_window: x::Window,
target_type: x::Atom,
max_req_bytes: usize,
}
pub struct WaylandSelection<T: SelectionType> {
mimes: Vec<SelectionTargetId>,
inner: ForeignSelection<T>,
incr_data: Option<WaylandIncrInfo>,
}
impl<T: SelectionType> WaylandSelection<T> {
fn check_for_incr(&mut self, connection: &xcb::Connection) -> Option<bool> {
let incr_data = self.incr_data.as_mut()?;
let range_start = incr_data.range.start;
let range_len = std::cmp::min(incr_data.max_req_bytes, incr_data.range.end - range_start);
if let Err(e) = connection.send_and_check_request(&x::ChangeProperty {
mode: x::PropMode::Append,
window: incr_data.target_window,
property: incr_data.property,
r#type: incr_data.target_type,
data: &incr_data.data[range_start..][..range_len],
}) {
warn!("failed to write selection data: {e:?}");
self.incr_data = None;
return Some(true);
}
incr_data.range.start += range_len;
if range_len == 0 {
debug!(
"completed incr for mime {}",
get_atom_name(connection, incr_data.target_type)
);
self.incr_data = None;
} else {
debug!(
"received some incr data for {}",
get_atom_name(connection, incr_data.target_type)
);
}
Some(true)
}
}
enum CurrentSelection<T: SelectionType> {
X11(Rc<Selection>),
Wayland {
mimes: Vec<SelectionTargetId>,
inner: ForeignSelection<T>,
},
Wayland(WaylandSelection<T>),
}
struct SelectionData<T: SelectionType> {
@ -198,10 +245,11 @@ trait SelectionDataImpl {
);
fn x11_selection(&self) -> Option<&Selection>;
fn handle_selection_request(
&self,
&mut self,
connection: &xcb::Connection,
atoms: &super::Atoms,
request: &x::SelectionRequestEvent,
max_req_bytes: usize,
success: &dyn Fn(),
refuse: &dyn Fn(),
server_state: &mut RealServerState,
@ -217,6 +265,12 @@ impl<T: SelectionType> SelectionData<T> {
current_selection: None,
}
}
fn wayland_selection_mut(&mut self) -> Option<&mut WaylandSelection<T>> {
match &mut self.current_selection {
Some(CurrentSelection::Wayland(sel)) => Some(sel),
_ => None,
}
}
}
impl<T: SelectionType> SelectionDataImpl for SelectionData<T> {
@ -359,15 +413,21 @@ impl<T: SelectionType> SelectionDataImpl for SelectionData<T> {
}
fn handle_selection_request(
&self,
&mut self,
connection: &xcb::Connection,
atoms: &super::Atoms,
request: &x::SelectionRequestEvent,
max_req_bytes: usize,
success: &dyn Fn(),
refuse: &dyn Fn(),
server_state: &mut RealServerState,
) {
let Some(CurrentSelection::Wayland { mimes, inner }) = &self.current_selection else {
let Some(CurrentSelection::Wayland(WaylandSelection {
mimes,
inner,
ref mut incr_data,
})) = &mut self.current_selection
else {
warn!("Got selection request, but we don't seem to be the selection owner");
refuse();
return;
@ -405,17 +465,52 @@ impl<T: SelectionType> SelectionDataImpl for SelectionData<T> {
.cloned()
.unwrap_or_else(|| target.name.clone());
let data = inner.receive(mime_name, server_state);
match connection.send_and_check_request(&x::ChangeProperty {
mode: x::PropMode::Replace,
window: request.requestor(),
property: request.property(),
r#type: target.atom,
data: &data,
}) {
Ok(_) => success(),
Err(e) => {
warn!("Failed setting selection property: {e:?}");
if data.len() > max_req_bytes {
if let Err(e) = connection.send_and_check_request(&x::ChangeWindowAttributes {
window: request.requestor(),
value_list: &[x::Cw::EventMask(x::EventMask::PROPERTY_CHANGE)],
}) {
warn!("Failed to set up property change notifications: {e:?}");
refuse();
return;
}
if let Err(e) = connection.send_and_check_request(&x::ChangeProperty {
mode: x::PropMode::Replace,
window: request.requestor(),
property: request.property(),
r#type: atoms.incr,
data: &[data.len() as u32],
}) {
warn!("Failed to set incr property for large transfer: {e:?}");
refuse();
return;
}
debug!(
"beginning incr for {}",
get_atom_name(connection, target.atom)
);
*incr_data = Some(WaylandIncrInfo {
range: 0..data.len(),
data,
target_window: request.requestor(),
property: request.property(),
target_type: target.atom,
max_req_bytes,
});
success()
} else {
match connection.send_and_check_request(&x::ChangeProperty {
mode: x::PropMode::Replace,
window: request.requestor(),
property: request.property(),
r#type: target.atom,
data: &data,
}) {
Ok(_) => success(),
Err(e) => {
warn!("Failed setting selection property: {e:?}");
refuse();
}
}
}
}
@ -503,10 +598,12 @@ impl XState {
});
}
self.selection_state.clipboard.current_selection = Some(CurrentSelection::Wayland {
mimes,
inner: selection,
});
self.selection_state.clipboard.current_selection =
Some(CurrentSelection::Wayland(WaylandSelection {
mimes,
inner: selection,
incr_data: None,
}));
self.selection_state
.clipboard
.set_owner(&self.connection, self.wm_window);
@ -559,10 +656,12 @@ impl XState {
});
}
self.selection_state.primary.current_selection = Some(CurrentSelection::Wayland {
mimes,
inner: selection,
});
self.selection_state.primary.current_selection =
Some(CurrentSelection::Wayland(WaylandSelection {
mimes,
inner: selection,
incr_data: None,
}));
self.selection_state
.primary
.set_owner(&self.connection, self.wm_window);
@ -676,6 +775,7 @@ impl XState {
&self.connection,
&self.atoms,
e,
self.max_req_bytes,
&success,
&refuse,
server_state,
@ -725,15 +825,28 @@ impl XState {
&mut self,
event: &x::PropertyNotifyEvent,
) -> bool {
for data in [
&self.selection_state.primary as &dyn SelectionDataImpl,
&self.selection_state.clipboard as _,
] {
if let Some(selection) = &data.x11_selection() {
return selection.check_for_incr(event);
fn inner<T: SelectionType>(
connection: &xcb::Connection,
event: &x::PropertyNotifyEvent,
data: &mut SelectionData<T>,
) -> Option<bool> {
match event.state() {
x::Property::NewValue => {
if let Some(selection) = &data.x11_selection() {
return Some(selection.check_for_incr(event));
}
}
x::Property::Delete => {
if let Some(selection) = data.wayland_selection_mut() {
return selection.check_for_incr(connection);
}
}
}
None
}
false
inner(&self.connection, event, &mut self.selection_state.primary)
.or_else(|| inner(&self.connection, event, &mut self.selection_state.clipboard))
.unwrap_or(false)
}
}