servo/components/script/dom/bindings/settings_stack.rs
Josh Matthews b4079b3ff3
Move generated bindings to script_bindings (#36323)
This is the final step of #1799, where the majority of the generated
code for the JS bindings is now compiled as part of the script_bindings
build step. The remaining pieces in script must live there because they
refer to concrete DOM types; all code in script_bindings is generic over
the
[DomTypes](https://doc.servo.org/script/dom/bindings/codegen/DomTypes/trait.DomTypes.html)
trait.

My testing with incremental builds shows me a 12 second reduction in
build times on my 2024 M4 Macbook Pro when modifying code in the script
crate after these changes. Before this PR those changes took 20 seconds
to rebuild Servo, and now they take 8 seconds.

Testing: Existing WPT tests ensure no regressions.
Fixes: #1799

---------

Signed-off-by: Josh Matthews <josh@joshmatthews.net>
2025-04-04 06:45:08 +00:00

80 lines
2.6 KiB
Rust

/* This Source Code Form is subject to the terms of the Mozilla Public
* 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/. */
use std::cell::RefCell;
use js::jsapi::{GetScriptedCallerGlobal, JSTracer};
use js::rust::Runtime;
use script_bindings::settings_stack::*;
//use script_bindings::interfaces::{DomHelpers, GlobalScopeHelpers};
use crate::dom::bindings::root::DomRoot;
use crate::dom::bindings::trace::JSTraceable;
use crate::dom::globalscope::GlobalScope;
thread_local!(pub(super) static STACK: RefCell<Vec<StackEntry<crate::DomTypeHolder>>> = const {
RefCell::new(Vec::new())
});
/// Traces the script settings stack.
pub(crate) unsafe fn trace(tracer: *mut JSTracer) {
STACK.with(|stack| {
stack.borrow().trace(tracer);
})
}
pub(crate) fn is_execution_stack_empty() -> bool {
STACK.with(|stack| stack.borrow().is_empty())
}
pub(crate) type AutoEntryScript = GenericAutoEntryScript<crate::DomTypeHolder>;
/// Returns the ["entry"] global object.
///
/// ["entry"]: https://html.spec.whatwg.org/multipage/#entry
pub(crate) fn entry_global() -> DomRoot<GlobalScope> {
STACK
.with(|stack| {
stack
.borrow()
.iter()
.rev()
.find(|entry| entry.kind == StackEntryKind::Entry)
.map(|entry| DomRoot::from_ref(&*entry.global))
})
.unwrap()
}
pub type AutoIncumbentScript = GenericAutoIncumbentScript<crate::DomTypeHolder>;
/// Returns the ["incumbent"] global object.
///
/// ["incumbent"]: https://html.spec.whatwg.org/multipage/#incumbent
pub(crate) fn incumbent_global() -> Option<DomRoot<GlobalScope>> {
// https://html.spec.whatwg.org/multipage/#incumbent-settings-object
// Step 1, 3: See what the JS engine has to say. If we've got a scripted
// caller override in place, the JS engine will lie to us and pretend that
// there's nothing on the JS stack, which will cause us to check the
// incumbent script stack below.
unsafe {
let Some(cx) = Runtime::get() else {
// It's not meaningful to return a global object if the runtime
// no longer exists.
return None;
};
let global = GetScriptedCallerGlobal(cx.as_ptr());
if !global.is_null() {
return Some(GlobalScope::from_object(global));
}
}
// Step 2: nothing from the JS engine. Let's use whatever's on the explicit stack.
STACK.with(|stack| {
stack
.borrow()
.last()
.map(|entry| DomRoot::from_ref(&*entry.global))
})
}