servo/components/script_bindings/finalize.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

74 lines
2.5 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/. */
//! Generic finalizer implementations for DOM binding implementations.
use std::any::type_name;
use std::{mem, ptr};
use js::glue::JS_GetReservedSlot;
use js::jsapi::JSObject;
use js::jsval::UndefinedValue;
use js::rust::GCMethods;
use crate::codegen::PrototypeList::PROTO_OR_IFACE_LENGTH;
use crate::utils::{ProtoOrIfaceArray, get_proto_or_iface_array};
use crate::weakref::{DOM_WEAK_SLOT, WeakBox, WeakReferenceable};
/// Drop the resources held by reserved slots of a global object
unsafe fn do_finalize_global(obj: *mut JSObject) {
let protolist = get_proto_or_iface_array(obj);
let list = (*protolist).as_mut_ptr();
for idx in 0..PROTO_OR_IFACE_LENGTH as isize {
let entry = list.offset(idx);
let value = *entry;
<*mut JSObject>::post_barrier(entry, value, ptr::null_mut());
}
let _: Box<ProtoOrIfaceArray> = Box::from_raw(protolist);
}
/// # Safety
/// `this` must point to a valid, non-null instance of T.
pub(crate) unsafe fn finalize_common<T>(this: *const T) {
if !this.is_null() {
// The pointer can be null if the object is the unforgeable holder of that interface.
let _ = Box::from_raw(this as *mut T);
}
debug!("{} finalize: {:p}", type_name::<T>(), this);
}
/// # Safety
/// `obj` must point to a valid, non-null JS object.
/// `this` must point to a valid, non-null instance of T.
pub(crate) unsafe fn finalize_global<T>(obj: *mut JSObject, this: *const T) {
do_finalize_global(obj);
finalize_common::<T>(this);
}
/// # Safety
/// `obj` must point to a valid, non-null JS object.
/// `this` must point to a valid, non-null instance of T.
pub(crate) unsafe fn finalize_weak_referenceable<T: WeakReferenceable>(
obj: *mut JSObject,
this: *const T,
) {
let mut slot = UndefinedValue();
JS_GetReservedSlot(obj, DOM_WEAK_SLOT, &mut slot);
let weak_box_ptr = slot.to_private() as *mut WeakBox<T>;
if !weak_box_ptr.is_null() {
let count = {
let weak_box = &*weak_box_ptr;
assert!(weak_box.value.get().is_some());
assert!(weak_box.count.get() > 0);
weak_box.value.set(None);
let count = weak_box.count.get() - 1;
weak_box.count.set(count);
count
};
if count == 0 {
mem::drop(Box::from_raw(weak_box_ptr));
}
}
finalize_common::<T>(this);
}