Add preference observer API for runtime webxr preference changes (#38649)

Adds a global preference observer that is notified whenever any
preference value is updated. This is used to support runtime
configuration of WebXR automated testing, which is a prerequisite for
running multiple WPT tests in a single browser session.

Testing: Ran `./mach test-wpt /webxr --product=servodriver`
Fixes: #38647

---------

Signed-off-by: Josh Matthews <josh@joshmatthews.net>
This commit is contained in:
Josh Matthews 2025-08-16 04:49:13 -04:00 committed by GitHub
parent fc3feceee5
commit f19b2f6e84
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GPG key ID: B5690EEEBB952194
4 changed files with 63 additions and 6 deletions

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@ -34,6 +34,12 @@ fn servo_preferences_derive(input: synstructure::Structure) -> TokenStream {
set_match_cases.extend(quote!(stringify!(#name) => self.#name = value.try_into().unwrap(),)) set_match_cases.extend(quote!(stringify!(#name) => self.#name = value.try_into().unwrap(),))
} }
let mut comparisons = quote!();
for field in named_fields.named.iter() {
let name = field.ident.as_ref().unwrap();
comparisons.extend(quote!(if self.#name != other.#name { changes.push((stringify!(#name), self.#name.clone().into(),)) }))
}
let structure_name = &ast.ident; let structure_name = &ast.ident;
quote! { quote! {
impl #structure_name { impl #structure_name {
@ -50,6 +56,12 @@ fn servo_preferences_derive(input: synstructure::Structure) -> TokenStream {
_ => { panic!("Unknown preference: {:?}", name); } _ => { panic!("Unknown preference: {:?}", name); }
} }
} }
pub fn diff(&self, other: &Self) -> Vec<(&'static str, PrefValue)> {
let mut changes = vec![];
#comparisons
changes
}
} }
} }
} }

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@ -11,12 +11,22 @@ pub use crate::pref_util::PrefValue;
static PREFERENCES: RwLock<Preferences> = RwLock::new(Preferences::const_default()); static PREFERENCES: RwLock<Preferences> = RwLock::new(Preferences::const_default());
pub trait Observer: Send + Sync {
fn prefs_changed(&self, _changes: Vec<(&'static str, PrefValue)>) {}
}
static OBSERVER: RwLock<Option<Box<dyn Observer>>> = RwLock::new(None);
#[inline] #[inline]
/// Get the current set of global preferences for Servo. /// Get the current set of global preferences for Servo.
pub fn get() -> RwLockReadGuard<'static, Preferences> { pub fn get() -> RwLockReadGuard<'static, Preferences> {
PREFERENCES.read().unwrap() PREFERENCES.read().unwrap()
} }
pub fn set_observer(observer: Box<dyn Observer>) {
*OBSERVER.write().unwrap() = Some(observer);
}
pub fn set(preferences: Preferences) { pub fn set(preferences: Preferences) {
// Map between Stylo preference names and Servo preference names as the This should be // Map between Stylo preference names and Servo preference names as the This should be
// kept in sync with components/script/dom/bindings/codegen/run.py which generates the // kept in sync with components/script/dom/bindings/codegen/run.py which generates the
@ -39,7 +49,13 @@ pub fn set(preferences: Preferences) {
preferences.layout_container_queries_enabled, preferences.layout_container_queries_enabled,
); );
let changed = preferences.diff(&PREFERENCES.read().unwrap());
*PREFERENCES.write().unwrap() = preferences; *PREFERENCES.write().unwrap() = preferences;
if let Some(observer) = OBSERVER.read().unwrap().as_deref() {
observer.prefs_changed(changed);
}
} }
/// A convenience macro for accessing a preference value using its static path. /// A convenience macro for accessing a preference value using its static path.

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@ -2,6 +2,7 @@
* License, v. 2.0. If a copy of the MPL was not distributed with this * License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at https://mozilla.org/MPL/2.0/. */ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
use std::sync::atomic::{AtomicBool, Ordering};
use std::sync::{Arc, Mutex}; use std::sync::{Arc, Mutex};
use std::thread; use std::thread;
@ -19,8 +20,15 @@ use webxr_api::{
use crate::{SurfmanGL, SurfmanLayerManager}; use crate::{SurfmanGL, SurfmanLayerManager};
#[derive(Default)] pub struct HeadlessMockDiscovery {
pub struct HeadlessMockDiscovery {} enabled: Arc<AtomicBool>,
}
impl HeadlessMockDiscovery {
pub fn new(enabled: Arc<AtomicBool>) -> Self {
Self { enabled }
}
}
struct HeadlessDiscovery { struct HeadlessDiscovery {
data: Arc<Mutex<HeadlessDeviceData>>, data: Arc<Mutex<HeadlessDeviceData>>,
@ -76,6 +84,10 @@ impl MockDiscoveryAPI<SurfmanGL> for HeadlessMockDiscovery {
init: MockDeviceInit, init: MockDeviceInit,
receiver: WebXrReceiver<MockDeviceMsg>, receiver: WebXrReceiver<MockDeviceMsg>,
) -> Result<Box<dyn DiscoveryAPI<SurfmanGL>>, Error> { ) -> Result<Box<dyn DiscoveryAPI<SurfmanGL>>, Error> {
if !self.enabled.load(Ordering::Relaxed) {
return Err(Error::NoMatchingDevice);
}
let viewer_origin = init.viewer_origin; let viewer_origin = init.viewer_origin;
let floor_transform = init.floor_origin.map(|f| f.inverse()); let floor_transform = init.floor_origin.map(|f| f.inverse());
let views = init.views.clone(); let views = init.views.clone();

View file

@ -4,9 +4,11 @@
use std::cell::RefCell; use std::cell::RefCell;
use std::rc::Rc; use std::rc::Rc;
use std::sync::Arc;
use std::sync::atomic::{AtomicBool, Ordering};
use servo::config::pref; use servo::config::pref;
use servo::config::prefs::Preferences; use servo::config::prefs::{self, Preferences};
use servo::webxr::WebXrRegistry; use servo::webxr::WebXrRegistry;
use servo::webxr::glwindow::GlWindowDiscovery; use servo::webxr::glwindow::GlWindowDiscovery;
#[cfg(target_os = "windows")] #[cfg(target_os = "windows")]
@ -60,14 +62,29 @@ impl XrDiscoveryWebXrRegistry {
} }
} }
struct XrPrefObserver(Arc<AtomicBool>);
impl prefs::Observer for XrPrefObserver {
fn prefs_changed(&self, changes: Vec<(&'static str, prefs::PrefValue)>) {
if let Some((_, value)) = changes.iter().find(|(name, _)| *name == "dom_webxr_test") {
let prefs::PrefValue::Bool(value) = value else {
return;
};
self.0.store(*value, Ordering::Relaxed);
}
}
}
#[cfg(feature = "webxr")] #[cfg(feature = "webxr")]
impl WebXrRegistry for XrDiscoveryWebXrRegistry { impl WebXrRegistry for XrDiscoveryWebXrRegistry {
fn register(&self, xr: &mut servo::webxr::MainThreadRegistry) { fn register(&self, xr: &mut servo::webxr::MainThreadRegistry) {
use servo::webxr::headless::HeadlessMockDiscovery; use servo::webxr::headless::HeadlessMockDiscovery;
if pref!(dom_webxr_test) { let mock_enabled = Arc::new(AtomicBool::new(pref!(dom_webxr_test)));
xr.register_mock(HeadlessMockDiscovery::default()); xr.register_mock(HeadlessMockDiscovery::new(mock_enabled.clone()));
} else if let Some(xr_discovery) = self.xr_discovery.take() { prefs::set_observer(Box::new(XrPrefObserver(mock_enabled)));
if let Some(xr_discovery) = self.xr_discovery.take() {
match xr_discovery { match xr_discovery {
XrDiscovery::GlWindow(discovery) => xr.register(discovery), XrDiscovery::GlWindow(discovery) => xr.register(discovery),
#[cfg(target_os = "windows")] #[cfg(target_os = "windows")]