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Move more bindings code to script_bindings (#35578)

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* Move JSContext wrapper to script_bindings.

Signed-off-by: Josh Matthews <josh@joshmatthews.net>

* Move webidl constant bindings to script_bindings.

Signed-off-by: Josh Matthews <josh@joshmatthews.net>

* Move CanGc to script_bindings.

Signed-off-by: Josh Matthews <josh@joshmatthews.net>

* Move Dom<T> and Root<T> types to script_bindings.

Signed-off-by: Josh Matthews <josh@joshmatthews.net>

* Formatting.

Signed-off-by: Josh Matthews <josh@joshmatthews.net>

* Extra docs for new traits.

Signed-off-by: Josh Matthews <josh@joshmatthews.net>

* Fix clippy warnings.

Signed-off-by: Josh Matthews <josh@joshmatthews.net>

---------

Signed-off-by: Josh Matthews <josh@joshmatthews.net>
This commit is contained in:
Josh Matthews 2025-02-21 23:46:56 -05:00 • committed by GitHub
parent 54286229ea
commit 35f21e426b
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23 changed files with 788 additions and 641 deletions
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140
components/script/dom/bindings/conversions.rs
View file

@ -32,17 +32,17 @@
//! | sequences | `Vec<T>` | | //! | sequences | `Vec<T>` | |
//! | union types | `T` | | //! | union types | `T` | |
use std::{ffi, ptr}; use std::ffi;
pub(crate) use js::conversions::{ pub(crate) use js::conversions::{
ConversionBehavior, ConversionResult, FromJSValConvertible, ToJSValConvertible, ConversionBehavior, ConversionResult, FromJSValConvertible, ToJSValConvertible,
}; };
use js::error::throw_type_error; use js::error::throw_type_error;
use js::glue::{GetProxyReservedSlot, IsWrapper, JS_GetReservedSlot, UnwrapObjectDynamic}; use js::glue::GetProxyReservedSlot;
use js::jsapi::{Heap, IsWindowProxy, JSContext, JSObject, JS_IsExceptionPending}; use js::jsapi::{Heap, IsWindowProxy, JSContext, JSObject, JS_IsExceptionPending};
use js::jsval::UndefinedValue; use js::jsval::UndefinedValue;
use js::rust::wrappers::{IsArrayObject, JS_GetProperty, JS_HasProperty}; use js::rust::wrappers::{IsArrayObject, JS_GetProperty, JS_HasProperty};
use js::rust::{is_dom_object, HandleId, HandleObject, HandleValue, MutableHandleValue}; use js::rust::{HandleId, HandleObject, HandleValue, MutableHandleValue};
use num_traits::Float; use num_traits::Float;
pub(crate) use script_bindings::conversions::*; pub(crate) use script_bindings::conversions::*;
@ -93,21 +93,6 @@ impl<T: Float + FromJSValConvertible<Config = ()>> FromJSValConvertible for Fini
} }
} }
impl<T: DomObject + IDLInterface> FromJSValConvertible for DomRoot<T> {
type Config = ();
unsafe fn from_jsval(
cx: *mut JSContext,
value: HandleValue,
_config: Self::Config,
) -> Result<ConversionResult<DomRoot<T>>, ()> {
Ok(match root_from_handlevalue(value, cx) {
Ok(result) => ConversionResult::Success(result),
Err(()) => ConversionResult::Failure("value is not an object".into()),
})
}
}
impl<T: ToJSValConvertible + JSTraceable> ToJSValConvertible for RootedTraceableBox<T> { impl<T: ToJSValConvertible + JSTraceable> ToJSValConvertible for RootedTraceableBox<T> {
#[inline] #[inline]
unsafe fn to_jsval(&self, cx: *mut JSContext, rval: MutableHandleValue) { unsafe fn to_jsval(&self, cx: *mut JSContext, rval: MutableHandleValue) {
@ -157,79 +142,6 @@ pub(crate) unsafe fn jsid_to_string(cx: *mut JSContext, id: HandleId) -> Option<
pub(crate) use script_bindings::conversions::is_dom_proxy; pub(crate) use script_bindings::conversions::is_dom_proxy;
/// The index of the slot wherein a pointer to the reflected DOM object is
/// stored for non-proxy bindings.
// We use slot 0 for holding the raw object. This is safe for both
// globals and non-globals.
pub(crate) const DOM_OBJECT_SLOT: u32 = 0;
/// Get the private pointer of a DOM object from a given reflector.
pub(crate) unsafe fn private_from_object(obj: *mut JSObject) -> *const libc::c_void {
let mut value = UndefinedValue();
if is_dom_object(obj) {
JS_GetReservedSlot(obj, DOM_OBJECT_SLOT, &mut value);
} else {
debug_assert!(is_dom_proxy(obj));
GetProxyReservedSlot(obj, 0, &mut value);
};
if value.is_undefined() {
ptr::null()
} else {
value.to_private()
}
}
pub(crate) enum PrototypeCheck {
Derive(fn(&'static DOMClass) -> bool),
Depth { depth: usize, proto_id: u16 },
}
/// Get a `*const libc::c_void` for the given DOM object, unwrapping any
/// wrapper around it first, and checking if the object is of the correct type.
///
/// Returns Err(()) if `obj` is an opaque security wrapper or if the object is
/// not an object for a DOM object of the given type (as defined by the
/// proto_id and proto_depth).
#[inline]
pub(crate) unsafe fn private_from_proto_check(
mut obj: *mut JSObject,
cx: *mut JSContext,
proto_check: PrototypeCheck,
) -> Result<*const libc::c_void, ()> {
let dom_class = get_dom_class(obj).or_else(|_| {
if IsWrapper(obj) {
trace!("found wrapper");
obj = UnwrapObjectDynamic(obj, cx, /* stopAtWindowProxy = */ false);
if obj.is_null() {
trace!("unwrapping security wrapper failed");
Err(())
} else {
assert!(!IsWrapper(obj));
trace!("unwrapped successfully");
get_dom_class(obj)
}
} else {
trace!("not a dom wrapper");
Err(())
}
})?;
let prototype_matches = match proto_check {
PrototypeCheck::Derive(f) => (f)(dom_class),
PrototypeCheck::Depth { depth, proto_id } => {
dom_class.interface_chain[depth] as u16 == proto_id
},
};
if prototype_matches {
trace!("good prototype");
Ok(private_from_object(obj))
} else {
trace!("bad prototype");
Err(())
}
}
/// Get a `*const libc::c_void` for the given DOM object, unless it is a DOM /// Get a `*const libc::c_void` for the given DOM object, unless it is a DOM
/// wrapper, and checking if the object is of the correct type. /// wrapper, and checking if the object is of the correct type.
/// ///
@ -250,17 +162,6 @@ unsafe fn private_from_proto_check_static(
} }
} }
/// Get a `*const T` for a DOM object accessible from a `JSObject`.
pub(crate) fn native_from_object<T>(obj: *mut JSObject, cx: *mut JSContext) -> Result<*const T, ()>
where
T: DomObject + IDLInterface,
{
unsafe {
private_from_proto_check(obj, cx, PrototypeCheck::Derive(T::derives))
.map(|ptr| ptr as *const T)
}
}
/// Get a `*const T` for a DOM object accessible from a `JSObject`, where the DOM object /// Get a `*const T` for a DOM object accessible from a `JSObject`, where the DOM object
/// is guaranteed not to be a wrapper. /// is guaranteed not to be a wrapper.
pub(crate) fn native_from_object_static<T>(obj: *mut JSObject) -> Result<*const T, ()> pub(crate) fn native_from_object_static<T>(obj: *mut JSObject) -> Result<*const T, ()>
@ -270,19 +171,6 @@ where
unsafe { private_from_proto_check_static(obj, T::derives).map(|ptr| ptr as *const T) } unsafe { private_from_proto_check_static(obj, T::derives).map(|ptr| ptr as *const T) }
} }
/// Get a `DomRoot<T>` for the given DOM object, unwrapping any wrapper
/// around it first, and checking if the object is of the correct type.
///
/// Returns Err(()) if `obj` is an opaque security wrapper or if the object is
/// not a reflector for a DOM object of the given type (as defined by the
/// proto_id and proto_depth).
pub(crate) fn root_from_object<T>(obj: *mut JSObject, cx: *mut JSContext) -> Result<DomRoot<T>, ()>
where
T: DomObject + IDLInterface,
{
native_from_object(obj, cx).map(|ptr| unsafe { DomRoot::from_ref(&*ptr) })
}
/// Get a `DomRoot<T>` for the given DOM object, unwrapping any wrapper /// Get a `DomRoot<T>` for the given DOM object, unwrapping any wrapper
/// around it first, and checking if the object is of the correct type. /// around it first, and checking if the object is of the correct type.
/// ///
@ -305,19 +193,7 @@ where
if !v.get().is_object() { if !v.get().is_object() {
return Err(()); return Err(());
} }
native_from_object(v.get().to_object(), cx) unsafe { native_from_object(v.get().to_object(), cx) }
}
/// Get a `DomRoot<T>` for a DOM object accessible from a `HandleValue`.
/// Caller is responsible for throwing a JS exception if needed in case of error.
pub(crate) fn root_from_handlevalue<T>(v: HandleValue, cx: *mut JSContext) -> Result<DomRoot<T>, ()>
where
T: DomObject + IDLInterface,
{
if !v.get().is_object() {
return Err(());
}
root_from_object(v.get().to_object(), cx)
} }
/// Get a `DomRoot<T>` for a DOM object accessible from a `HandleObject`. /// Get a `DomRoot<T>` for a DOM object accessible from a `HandleObject`.
@ -328,13 +204,7 @@ pub(crate) fn root_from_handleobject<T>(
where where
T: DomObject + IDLInterface, T: DomObject + IDLInterface,
{ {
root_from_object(obj.get(), cx) unsafe { root_from_object(obj.get(), cx) }
}
impl<T: DomObject> ToJSValConvertible for DomRoot<T> {
unsafe fn to_jsval(&self, cx: *mut JSContext, rval: MutableHandleValue) {
self.reflector().to_jsval(cx, rval);
}
} }
/// Returns whether `value` is an array-like object (Array, FileList, /// Returns whether `value` is an array-like object (Array, FileList,

2
components/script/dom/bindings/error.rs
View file

@ -220,7 +220,7 @@ impl ErrorInfo {
} }
fn from_dom_exception(object: HandleObject, cx: SafeJSContext) -> Option<ErrorInfo> { fn from_dom_exception(object: HandleObject, cx: SafeJSContext) -> Option<ErrorInfo> {
let exception = match root_from_object::<DOMException>(object.get(), *cx) { let exception = match unsafe { root_from_object::<DOMException>(object.get(), *cx) } {
Ok(exception) => exception, Ok(exception) => exception,
Err(_) => return None, Err(_) => return None,
}; };

2
components/script/dom/bindings/import.rs
View file

@ -97,6 +97,7 @@ pub(crate) mod module {
jsapi, typedarray, JSCLASS_GLOBAL_SLOT_COUNT, JSCLASS_IS_DOMJSCLASS, JSCLASS_IS_GLOBAL, jsapi, typedarray, JSCLASS_GLOBAL_SLOT_COUNT, JSCLASS_IS_DOMJSCLASS, JSCLASS_IS_GLOBAL,
JSCLASS_RESERVED_SLOTS_MASK, JS_CALLEE, JSCLASS_RESERVED_SLOTS_MASK, JS_CALLEE,
}; };
pub(crate) use script_bindings::constant::{ConstantSpec, ConstantVal};
pub(crate) use servo_config::pref; pub(crate) use servo_config::pref;
pub(crate) use super::base::*; pub(crate) use super::base::*;
@ -109,7 +110,6 @@ pub(crate) mod module {
pub(crate) use crate::dom::bindings::codegen::{ pub(crate) use crate::dom::bindings::codegen::{
InterfaceObjectMap, PrototypeList, RegisterBindings, InterfaceObjectMap, PrototypeList, RegisterBindings,
}; };
pub(crate) use crate::dom::bindings::constant::{ConstantSpec, ConstantVal};
pub(crate) use crate::dom::bindings::constructor::{ pub(crate) use crate::dom::bindings::constructor::{
call_default_constructor, call_html_constructor, pop_current_element_queue, call_default_constructor, call_html_constructor, pop_current_element_queue,
push_new_element_queue, push_new_element_queue,

2
components/script/dom/bindings/interface.rs
View file

@ -31,11 +31,11 @@ use js::rust::{
define_methods, define_properties, get_object_class, is_dom_class, maybe_wrap_object, define_methods, define_properties, get_object_class, is_dom_class, maybe_wrap_object,
HandleObject, HandleValue, MutableHandleObject, RealmOptions, HandleObject, HandleValue, MutableHandleObject, RealmOptions,
}; };
use script_bindings::constant::{define_constants, ConstantSpec};
use servo_url::MutableOrigin; use servo_url::MutableOrigin;
use crate::dom::bindings::codegen::InterfaceObjectMap::Globals; use crate::dom::bindings::codegen::InterfaceObjectMap::Globals;
use crate::dom::bindings::codegen::PrototypeList; use crate::dom::bindings::codegen::PrototypeList;
use crate::dom::bindings::constant::{define_constants, ConstantSpec};
use crate::dom::bindings::conversions::{get_dom_class, DOM_OBJECT_SLOT}; use crate::dom::bindings::conversions::{get_dom_class, DOM_OBJECT_SLOT};
use crate::dom::bindings::guard::Guard; use crate::dom::bindings::guard::Guard;
use crate::dom::bindings::principals::ServoJSPrincipals; use crate::dom::bindings::principals::ServoJSPrincipals;

1
components/script/dom/bindings/mod.rs
View file

@ -138,7 +138,6 @@ pub(crate) mod buffer_source;
pub(crate) mod callback; pub(crate) mod callback;
#[allow(dead_code)] #[allow(dead_code)]
pub(crate) mod cell; pub(crate) mod cell;
pub(crate) mod constant;
pub(crate) mod constructor; pub(crate) mod constructor;
pub(crate) mod conversions; pub(crate) mod conversions;
pub(crate) mod error; pub(crate) mod error;

2
components/script/dom/bindings/namespace.rs
View file

@ -9,8 +9,8 @@ use std::ptr;
use js::jsapi::{JSClass, JSFunctionSpec}; use js::jsapi::{JSClass, JSFunctionSpec};
use js::rust::{HandleObject, MutableHandleObject}; use js::rust::{HandleObject, MutableHandleObject};
use script_bindings::constant::ConstantSpec;
use super::constant::ConstantSpec;
use crate::dom::bindings::guard::Guard; use crate::dom::bindings::guard::Guard;
use crate::dom::bindings::interface::{create_object, define_on_global_object}; use crate::dom::bindings::interface::{create_object, define_on_global_object};
use crate::script_runtime::JSContext; use crate::script_runtime::JSContext;

402
components/script/dom/bindings/root.rs
View file

@ -24,232 +24,24 @@
//! originating `DomRoot<T>`. //! originating `DomRoot<T>`.
//! //!
use std::cell::{Cell, OnceCell, UnsafeCell}; use std::cell::{OnceCell, UnsafeCell};
use std::default::Default; use std::default::Default;
use std::hash::{Hash, Hasher}; use std::hash::{Hash, Hasher};
use std::marker::PhantomData; use std::marker::PhantomData;
use std::ops::Deref;
use std::{mem, ptr}; use std::{mem, ptr};
use js::jsapi::{JSObject, JSTracer}; use js::jsapi::{JSObject, JSTracer};
use malloc_size_of::{MallocSizeOf, MallocSizeOfOps}; use malloc_size_of::{MallocSizeOf, MallocSizeOfOps};
pub(crate) use script_bindings::root::*;
use script_layout_interface::TrustedNodeAddress; use script_layout_interface::TrustedNodeAddress;
use style::thread_state; use style::thread_state;
use crate::dom::bindings::conversions::DerivedFrom; use crate::dom::bindings::conversions::DerivedFrom;
use crate::dom::bindings::inheritance::Castable; use crate::dom::bindings::inheritance::Castable;
use crate::dom::bindings::reflector::{DomObject, MutDomObject, Reflector}; use crate::dom::bindings::reflector::DomObject;
use crate::dom::bindings::trace::{trace_reflector, JSTraceable}; use crate::dom::bindings::trace::JSTraceable;
use crate::dom::node::Node; use crate::dom::node::Node;
/// A rooted value.
#[cfg_attr(crown, crown::unrooted_must_root_lint::allow_unrooted_interior)]
pub(crate) struct Root<T: StableTraceObject> {
/// The value to root.
value: T,
/// List that ensures correct dynamic root ordering
root_list: *const RootCollection,
}
impl<T> Root<T>
where
T: StableTraceObject + 'static,
{
/// Create a new stack-bounded root for the provided value.
/// It cannot outlive its associated `RootCollection`, and it gives
/// out references which cannot outlive this new `Root`.
#[cfg_attr(crown, allow(crown::unrooted_must_root))]
pub(crate) unsafe fn new(value: T) -> Self {
unsafe fn add_to_root_list(object: *const dyn JSTraceable) -> *const RootCollection {
assert_in_script();
STACK_ROOTS.with(|root_list| {
let root_list = &*root_list.get().unwrap();
root_list.root(object);
root_list
})
}
let root_list = add_to_root_list(value.stable_trace_object());
Root { value, root_list }
}
}
/// `StableTraceObject` represents values that can be rooted through a stable address that will
/// not change for their whole lifetime.
/// It is an unsafe trait that requires implementors to ensure certain safety guarantees.
///
/// # Safety
///
/// Implementors of this trait must ensure that the `trace` method correctly accounts for all
/// owned and referenced objects, so that the garbage collector can accurately determine which
/// objects are still in use. Failing to adhere to this contract may result in undefined behavior,
/// such as use-after-free errors.
pub(crate) unsafe trait StableTraceObject {
/// Returns a stable trace object which address won't change for the whole
/// lifetime of the value.
fn stable_trace_object(&self) -> *const dyn JSTraceable;
}
unsafe impl<T> StableTraceObject for Dom<T>
where
T: DomObject,
{
fn stable_trace_object(&self) -> *const dyn JSTraceable {
// The JSTraceable impl for Reflector doesn't actually do anything,
// so we need this shenanigan to actually trace the reflector of the
// T pointer in Dom<T>.
#[cfg_attr(crown, allow(crown::unrooted_must_root))]
struct ReflectorStackRoot(Reflector);
unsafe impl JSTraceable for ReflectorStackRoot {
unsafe fn trace(&self, tracer: *mut JSTracer) {
trace_reflector(tracer, "on stack", &self.0);
}
}
unsafe { &*(self.reflector() as *const Reflector as *const ReflectorStackRoot) }
}
}
unsafe impl<T> StableTraceObject for MaybeUnreflectedDom<T>
where
T: DomObject,
{
fn stable_trace_object(&self) -> *const dyn JSTraceable {
// The JSTraceable impl for Reflector doesn't actually do anything,
// so we need this shenanigan to actually trace the reflector of the
// T pointer in Dom<T>.
#[cfg_attr(crown, allow(crown::unrooted_must_root))]
struct MaybeUnreflectedStackRoot<T>(T);
unsafe impl<T> JSTraceable for MaybeUnreflectedStackRoot<T>
where
T: DomObject,
{
unsafe fn trace(&self, tracer: *mut JSTracer) {
if self.0.reflector().get_jsobject().is_null() {
self.0.trace(tracer);
} else {
trace_reflector(tracer, "on stack", self.0.reflector());
}
}
}
unsafe { &*(self.ptr.as_ptr() as *const T as *const MaybeUnreflectedStackRoot<T>) }
}
}
impl<T> Deref for Root<T>
where
T: Deref + StableTraceObject,
{
type Target = <T as Deref>::Target;
fn deref(&self) -> &Self::Target {
assert_in_script();
&self.value
}
}
impl<T> Drop for Root<T>
where
T: StableTraceObject,
{
fn drop(&mut self) {
unsafe {
(*self.root_list).unroot(self.value.stable_trace_object());
}
}
}
/// A rooted reference to a DOM object.
pub(crate) type DomRoot<T> = Root<Dom<T>>;
impl<T: Castable> DomRoot<T> {
/// Cast a DOM object root upwards to one of the interfaces it derives from.
pub(crate) fn upcast<U>(root: DomRoot<T>) -> DomRoot<U>
where
U: Castable,
T: DerivedFrom<U>,
{
unsafe { mem::transmute::<DomRoot<T>, DomRoot<U>>(root) }
}
/// Cast a DOM object root downwards to one of the interfaces it might implement.
pub(crate) fn downcast<U>(root: DomRoot<T>) -> Option<DomRoot<U>>
where
U: DerivedFrom<T>,
{
if root.is::<U>() {
Some(unsafe { mem::transmute::<DomRoot<T>, DomRoot<U>>(root) })
} else {
None
}
}
}
impl<T: DomObject> DomRoot<T> {
/// Generate a new root from a reference
pub(crate) fn from_ref(unrooted: &T) -> DomRoot<T> {
unsafe { DomRoot::new(Dom::from_ref(unrooted)) }
}
/// Create a traced version of this rooted object.
///
/// # Safety
///
/// This should never be used to create on-stack values. Instead these values should always
/// end up as members of other DOM objects.
#[cfg_attr(crown, allow(crown::unrooted_must_root))]
pub(crate) fn as_traced(&self) -> Dom<T> {
Dom::from_ref(self)
}
}
impl<T> MallocSizeOf for DomRoot<T>
where
T: DomObject + MallocSizeOf,
{
fn size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
(**self).size_of(ops)
}
}
impl<T> PartialEq for DomRoot<T>
where
T: DomObject,
{
fn eq(&self, other: &Self) -> bool {
self.value == other.value
}
}
impl<T> Clone for DomRoot<T>
where
T: DomObject,
{
fn clone(&self) -> DomRoot<T> {
DomRoot::from_ref(self)
}
}
unsafe impl<T> JSTraceable for DomRoot<T>
where
T: DomObject,
{
unsafe fn trace(&self, _: *mut JSTracer) {
// Already traced.
}
}
/// A rooting mechanism for reflectors on the stack.
/// LIFO is not required.
///
/// See also [*Exact Stack Rooting - Storing a GCPointer on the CStack*][cstack].
///
/// [cstack]: https://developer.mozilla.org/en-US/docs/Mozilla/Projects/SpiderMonkey/Internals/GC/Exact_Stack_Rooting
pub(crate) struct RootCollection {
roots: UnsafeCell<Vec<*const dyn JSTraceable>>,
}
thread_local!(static STACK_ROOTS: Cell<Option<*const RootCollection>> = const { Cell::new(None) });
pub(crate) struct ThreadLocalStackRoots<'a>(PhantomData<&'a u32>); pub(crate) struct ThreadLocalStackRoots<'a>(PhantomData<&'a u32>);
impl<'a> ThreadLocalStackRoots<'a> { impl<'a> ThreadLocalStackRoots<'a> {
@ -265,48 +57,6 @@ impl Drop for ThreadLocalStackRoots<'_> {
} }
} }
impl RootCollection {
/// Create an empty collection of roots
pub(crate) fn new() -> RootCollection {
assert_in_script();
RootCollection {
roots: UnsafeCell::new(vec![]),
}
}
/// Starts tracking a trace object.
unsafe fn root(&self, object: *const dyn JSTraceable) {
assert_in_script();
(*self.roots.get()).push(object);
}
/// Stops tracking a trace object, asserting if it isn't found.
unsafe fn unroot(&self, object: *const dyn JSTraceable) {
assert_in_script();
let roots = &mut *self.roots.get();
match roots
.iter()
.rposition(|r| std::ptr::addr_eq(*r as *const (), object as *const ()))
{
Some(idx) => {
roots.remove(idx);
},
None => panic!("Can't remove a root that was never rooted!"),
}
}
}
/// SM Callback that traces the rooted reflectors
pub(crate) unsafe fn trace_roots(tracer: *mut JSTracer) {
trace!("tracing stack roots");
STACK_ROOTS.with(|collection| {
let collection = &*(*collection.get().unwrap()).roots.get();
for root in collection {
(**root).trace(tracer);
}
});
}
/// Get a slice of references to DOM objects. /// Get a slice of references to DOM objects.
pub(crate) trait DomSlice<T> pub(crate) trait DomSlice<T>
where where
@ -327,121 +77,24 @@ where
} }
} }
/// A traced reference to a DOM object pub(crate) trait ToLayout<T> {
///
/// This type is critical to making garbage collection work with the DOM,
/// but it is very dangerous; if garbage collection happens with a `Dom<T>`
/// on the stack, the `Dom<T>` can point to freed memory.
///
/// This should only be used as a field in other DOM objects.
#[cfg_attr(crown, crown::unrooted_must_root_lint::must_root)]
#[repr(transparent)]
pub(crate) struct Dom<T> {
ptr: ptr::NonNull<T>,
}
// Dom<T> is similar to Rc<T>, in that it's not always clear how to avoid double-counting.
// For now, we choose not to follow any such pointers.
impl<T> MallocSizeOf for Dom<T> {
fn size_of(&self, _ops: &mut MallocSizeOfOps) -> usize {
0
}
}
impl<T> Dom<T> {
/// Returns `LayoutDom<T>` containing the same pointer. /// Returns `LayoutDom<T>` containing the same pointer.
/// ///
/// # Safety /// # Safety
/// ///
/// The `self` parameter to this method must meet all the requirements of [`ptr::NonNull::as_ref`]. /// The `self` parameter to this method must meet all the requirements of [`ptr::NonNull::as_ref`].
pub(crate) unsafe fn to_layout(&self) -> LayoutDom<T> { unsafe fn to_layout(&self) -> LayoutDom<T>;
}
impl<T: DomObject> ToLayout<T> for Dom<T> {
unsafe fn to_layout(&self) -> LayoutDom<T> {
assert_in_layout(); assert_in_layout();
LayoutDom { LayoutDom {
value: self.ptr.as_ref(), value: self.as_ptr().as_ref().unwrap(),
} }
} }
} }
impl<T: DomObject> Dom<T> {
/// Create a `Dom<T>` from a `&T`
#[cfg_attr(crown, allow(crown::unrooted_must_root))]
pub(crate) fn from_ref(obj: &T) -> Dom<T> {
assert_in_script();
Dom {
ptr: ptr::NonNull::from(obj),
}
}
/// Return a rooted version of this DOM object ([`DomRoot<T>`]) suitable for use on the stack.
pub(crate) fn as_rooted(&self) -> DomRoot<T> {
DomRoot::from_ref(self)
}
}
impl<T: DomObject> Deref for Dom<T> {
type Target = T;
fn deref(&self) -> &T {
assert_in_script();
// We can only have &Dom<T> from a rooted thing, so it's safe to deref
// it to &T.
unsafe { &*self.ptr.as_ptr() }
}
}
unsafe impl<T: DomObject> JSTraceable for Dom<T> {
unsafe fn trace(&self, trc: *mut JSTracer) {
let trace_string;
let trace_info = if cfg!(debug_assertions) {
trace_string = format!("for {} on heap", ::std::any::type_name::<T>());
&trace_string[..]
} else {
"for DOM object on heap"
};
trace_reflector(trc, trace_info, (*self.ptr.as_ptr()).reflector());
}
}
/// A traced reference to a DOM object that may not be reflected yet.
#[cfg_attr(crown, crown::unrooted_must_root_lint::must_root)]
pub(crate) struct MaybeUnreflectedDom<T> {
ptr: ptr::NonNull<T>,
}
impl<T> MaybeUnreflectedDom<T>
where
T: DomObject,
{
#[cfg_attr(crown, allow(crown::unrooted_must_root))]
pub(crate) unsafe fn from_box(value: Box<T>) -> Self {
Self {
ptr: Box::leak(value).into(),
}
}
}
impl<T> Root<MaybeUnreflectedDom<T>>
where
T: DomObject,
{
pub(crate) fn as_ptr(&self) -> *const T {
self.value.ptr.as_ptr()
}
}
impl<T> Root<MaybeUnreflectedDom<T>>
where
T: MutDomObject,
{
pub(crate) unsafe fn reflect_with(self, obj: *mut JSObject) -> DomRoot<T> {
let ptr = self.as_ptr();
drop(self);
let root = DomRoot::from_ref(&*ptr);
root.init_reflector(obj);
root
}
}
/// An unrooted reference to a DOM object for use in layout. `Layout*Helpers` /// An unrooted reference to a DOM object for use in layout. `Layout*Helpers`
/// traits must be implemented on this. /// traits must be implemented on this.
#[cfg_attr(crown, crown::unrooted_must_root_lint::allow_unrooted_interior)] #[cfg_attr(crown, crown::unrooted_must_root_lint::allow_unrooted_interior)]
@ -498,20 +151,6 @@ where
impl<T> Copy for LayoutDom<'_, T> {} impl<T> Copy for LayoutDom<'_, T> {}
impl<T> PartialEq for Dom<T> {
fn eq(&self, other: &Dom<T>) -> bool {
self.ptr.as_ptr() == other.ptr.as_ptr()
}
}
impl<'a, T: DomObject> PartialEq<&'a T> for Dom<T> {
fn eq(&self, other: &&'a T) -> bool {
*self == Dom::from_ref(*other)
}
}
impl<T> Eq for Dom<T> {}
impl<T> PartialEq for LayoutDom<'_, T> { impl<T> PartialEq for LayoutDom<'_, T> {
fn eq(&self, other: &Self) -> bool { fn eq(&self, other: &Self) -> bool {
std::ptr::eq(self.value, other.value) std::ptr::eq(self.value, other.value)
@ -520,27 +159,12 @@ impl<T> PartialEq for LayoutDom<'_, T> {
impl<T> Eq for LayoutDom<'_, T> {} impl<T> Eq for LayoutDom<'_, T> {}
impl<T> Hash for Dom<T> {
fn hash<H: Hasher>(&self, state: &mut H) {
self.ptr.as_ptr().hash(state)
}
}
impl<T> Hash for LayoutDom<'_, T> { impl<T> Hash for LayoutDom<'_, T> {
fn hash<H: Hasher>(&self, state: &mut H) { fn hash<H: Hasher>(&self, state: &mut H) {
(self.value as *const T).hash(state) (self.value as *const T).hash(state)
} }
} }
impl<T> Clone for Dom<T> {
#[inline]
#[cfg_attr(crown, allow(crown::unrooted_must_root))]
fn clone(&self) -> Self {
assert_in_script();
Dom { ptr: self.ptr }
}
}
impl<T> Clone for LayoutDom<'_, T> { impl<T> Clone for LayoutDom<'_, T> {
#[inline] #[inline]
#[allow(clippy::non_canonical_clone_impl)] #[allow(clippy::non_canonical_clone_impl)]
@ -616,10 +240,6 @@ impl<T: DomObject + PartialEq> PartialEq<T> for MutDom<T> {
} }
} }
pub(crate) fn assert_in_script() {
debug_assert!(thread_state::get().is_script());
}
pub(crate) fn assert_in_layout() { pub(crate) fn assert_in_layout() {
debug_assert!(thread_state::get().is_layout()); debug_assert!(thread_state::get().is_layout());
} }

26
components/script/dom/bindings/trace.rs
View file

@ -42,12 +42,13 @@ use indexmap::IndexMap;
/// A trait to allow tracing (only) DOM objects. /// A trait to allow tracing (only) DOM objects.
pub(crate) use js::gc::Traceable as JSTraceable; pub(crate) use js::gc::Traceable as JSTraceable;
pub(crate) use js::gc::{RootableVec, RootedVec}; pub(crate) use js::gc::{RootableVec, RootedVec};
use js::glue::{CallObjectTracer, CallScriptTracer, CallStringTracer, CallValueTracer}; use js::glue::{CallScriptTracer, CallStringTracer, CallValueTracer};
use js::jsapi::{GCTraceKindToAscii, Heap, JSObject, JSScript, JSString, JSTracer, TraceKind}; use js::jsapi::{GCTraceKindToAscii, Heap, JSScript, JSString, JSTracer, TraceKind};
use js::jsval::JSVal; use js::jsval::JSVal;
use js::rust::{GCMethods, Handle}; use js::rust::{GCMethods, Handle};
use malloc_size_of::{MallocSizeOf, MallocSizeOfOps}; use malloc_size_of::{MallocSizeOf, MallocSizeOfOps};
use parking_lot::RwLock; use parking_lot::RwLock;
pub(crate) use script_bindings::trace::*;
use servo_arc::Arc as ServoArc; use servo_arc::Arc as ServoArc;
use smallvec::SmallVec; use smallvec::SmallVec;
use style::author_styles::AuthorStyles; use style::author_styles::AuthorStyles;
@ -61,7 +62,7 @@ use webxr_api::{Finger, Hand};
use crate::dom::bindings::cell::DomRefCell; use crate::dom::bindings::cell::DomRefCell;
use crate::dom::bindings::error::Error; use crate::dom::bindings::error::Error;
use crate::dom::bindings::refcounted::{Trusted, TrustedPromise}; use crate::dom::bindings::refcounted::{Trusted, TrustedPromise};
use crate::dom::bindings::reflector::{DomObject, Reflector}; use crate::dom::bindings::reflector::DomObject;
use crate::dom::htmlimageelement::SourceSet; use crate::dom::htmlimageelement::SourceSet;
use crate::dom::htmlmediaelement::HTMLMediaElementFetchContext; use crate::dom::htmlmediaelement::HTMLMediaElementFetchContext;
use crate::dom::windowproxy::WindowProxyHandler; use crate::dom::windowproxy::WindowProxyHandler;
@ -285,25 +286,6 @@ pub(crate) fn trace_jsval(tracer: *mut JSTracer, description: &str, val: &Heap<J
} }
} }
/// Trace the `JSObject` held by `reflector`.
#[cfg_attr(crown, allow(crown::unrooted_must_root))]
pub(crate) fn trace_reflector(tracer: *mut JSTracer, description: &str, reflector: &Reflector) {
trace!("tracing reflector {}", description);
trace_object(tracer, description, reflector.rootable())
}
/// Trace a `JSObject`.
pub(crate) fn trace_object(tracer: *mut JSTracer, description: &str, obj: &Heap<*mut JSObject>) {
unsafe {
trace!("tracing {}", description);
CallObjectTracer(
tracer,
obj.ptr.get() as *mut _,
GCTraceKindToAscii(TraceKind::Object),
);
}
}
#[allow(dead_code)] #[allow(dead_code)]
/// Trace a `JSString`. /// Trace a `JSString`.
pub(crate) fn trace_string(tracer: *mut JSTracer, description: &str, s: &Heap<*mut JSString>) { pub(crate) fn trace_string(tracer: *mut JSTracer, description: &str, s: &Heap<*mut JSString>) {

2
components/script/dom/document.rs
View file

@ -111,7 +111,7 @@ use crate::dom::bindings::inheritance::{Castable, ElementTypeId, HTMLElementType
use crate::dom::bindings::num::Finite; use crate::dom::bindings::num::Finite;
use crate::dom::bindings::refcounted::{Trusted, TrustedPromise}; use crate::dom::bindings::refcounted::{Trusted, TrustedPromise};
use crate::dom::bindings::reflector::{reflect_dom_object_with_proto, DomGlobal}; use crate::dom::bindings::reflector::{reflect_dom_object_with_proto, DomGlobal};
use crate::dom::bindings::root::{Dom, DomRoot, DomSlice, LayoutDom, MutNullableDom}; use crate::dom::bindings::root::{Dom, DomRoot, DomSlice, LayoutDom, MutNullableDom, ToLayout};
use crate::dom::bindings::str::{DOMString, USVString}; use crate::dom::bindings::str::{DOMString, USVString};
use crate::dom::bindings::trace::{HashMapTracedValues, NoTrace}; use crate::dom::bindings::trace::{HashMapTracedValues, NoTrace};
#[cfg(feature = "webgpu")] #[cfg(feature = "webgpu")]

80
components/script/dom/element.rs
View file

@ -86,7 +86,7 @@ use crate::dom::bindings::error::{Error, ErrorResult, Fallible};
use crate::dom::bindings::inheritance::{Castable, ElementTypeId, HTMLElementTypeId, NodeTypeId}; use crate::dom::bindings::inheritance::{Castable, ElementTypeId, HTMLElementTypeId, NodeTypeId};
use crate::dom::bindings::refcounted::{Trusted, TrustedPromise}; use crate::dom::bindings::refcounted::{Trusted, TrustedPromise};
use crate::dom::bindings::reflector::DomObject; use crate::dom::bindings::reflector::DomObject;
use crate::dom::bindings::root::{Dom, DomRoot, LayoutDom, MutNullableDom}; use crate::dom::bindings::root::{Dom, DomRoot, LayoutDom, MutNullableDom, ToLayout};
use crate::dom::bindings::str::{DOMString, USVString}; use crate::dom::bindings::str::{DOMString, USVString};
use crate::dom::bindings::xmlname::{ use crate::dom::bindings::xmlname::{
matches_name_production, namespace_from_domstring, validate_and_extract, matches_name_production, namespace_from_domstring, validate_and_extract,
@ -162,7 +162,7 @@ use crate::task::TaskOnce;
/// <https://dom.spec.whatwg.org/#element> /// <https://dom.spec.whatwg.org/#element>
#[dom_struct] #[dom_struct]
pub(crate) struct Element { pub struct Element {
node: Node, node: Node,
#[no_trace] #[no_trace]
local_name: LocalName, local_name: LocalName,
@ -203,12 +203,6 @@ impl fmt::Debug for Element {
} }
} }
impl fmt::Debug for DomRoot<Element> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
(**self).fmt(f)
}
}
#[derive(MallocSizeOf, PartialEq)] #[derive(MallocSizeOf, PartialEq)]
pub(crate) enum ElementCreator { pub(crate) enum ElementCreator {
ParserCreated(u64), ParserCreated(u64),
@ -3025,7 +3019,11 @@ impl ElementMethods<crate::DomTypeHolder> for Element {
let quirks_mode = doc.quirks_mode(); let quirks_mode = doc.quirks_mode();
let element = DomRoot::from_ref(self); let element = DomRoot::from_ref(self);
Ok(dom_apis::element_matches(&element, &selectors, quirks_mode)) Ok(dom_apis::element_matches(
&SelectorWrapper::Borrowed(&element),
&selectors,
quirks_mode,
))
} }
// https://dom.spec.whatwg.org/#dom-element-webkitmatchesselector // https://dom.spec.whatwg.org/#dom-element-webkitmatchesselector
@ -3047,10 +3045,11 @@ impl ElementMethods<crate::DomTypeHolder> for Element {
let quirks_mode = doc.quirks_mode(); let quirks_mode = doc.quirks_mode();
Ok(dom_apis::element_closest( Ok(dom_apis::element_closest(
DomRoot::from_ref(self), SelectorWrapper::Owned(DomRoot::from_ref(self)),
&selectors, &selectors,
quirks_mode, quirks_mode,
)) )
.map(SelectorWrapper::into_owned))
} }
// https://dom.spec.whatwg.org/#dom-element-insertadjacentelement // https://dom.spec.whatwg.org/#dom-element-insertadjacentelement
@ -3831,7 +3830,43 @@ impl VirtualMethods for Element {
} }
} }
impl SelectorsElement for DomRoot<Element> { #[derive(Clone, PartialEq)]
/// A type that wraps a DomRoot value so we can implement the SelectorsElement
/// trait without violating the orphan rule. Since the trait assumes that the
/// return type and self type of various methods is the same type that it is
/// implemented against, we need to be able to represent multiple ownership styles.
pub enum SelectorWrapper<'a> {
Borrowed(&'a DomRoot<Element>),
Owned(DomRoot<Element>),
}
impl fmt::Debug for SelectorWrapper<'_> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
self.deref().fmt(f)
}
}
impl Deref for SelectorWrapper<'_> {
type Target = DomRoot<Element>;
fn deref(&self) -> &Self::Target {
match self {
SelectorWrapper::Owned(r) => r,
SelectorWrapper::Borrowed(r) => r,
}
}
}
impl SelectorWrapper<'_> {
fn into_owned(self) -> DomRoot<Element> {
match self {
SelectorWrapper::Owned(r) => r,
SelectorWrapper::Borrowed(r) => r.clone(),
}
}
}
impl SelectorsElement for SelectorWrapper<'_> {
type Impl = SelectorImpl; type Impl = SelectorImpl;
#[allow(unsafe_code)] #[allow(unsafe_code)]
@ -3839,8 +3874,10 @@ impl SelectorsElement for DomRoot<Element> {
::selectors::OpaqueElement::new(unsafe { &*self.reflector().get_jsobject().get() }) ::selectors::OpaqueElement::new(unsafe { &*self.reflector().get_jsobject().get() })
} }
fn parent_element(&self) -> Option<DomRoot<Element>> { fn parent_element(&self) -> Option<Self> {
self.upcast::<Node>().GetParentElement() self.upcast::<Node>()
.GetParentElement()
.map(SelectorWrapper::Owned)
} }
fn parent_node_is_shadow_root(&self) -> bool { fn parent_node_is_shadow_root(&self) -> bool {
@ -3853,6 +3890,7 @@ impl SelectorsElement for DomRoot<Element> {
fn containing_shadow_host(&self) -> Option<Self> { fn containing_shadow_host(&self) -> Option<Self> {
self.containing_shadow_root() self.containing_shadow_root()
.map(|shadow_root| shadow_root.Host()) .map(|shadow_root| shadow_root.Host())
.map(SelectorWrapper::Owned)
} }
fn is_pseudo_element(&self) -> bool { fn is_pseudo_element(&self) -> bool {
@ -3867,22 +3905,24 @@ impl SelectorsElement for DomRoot<Element> {
false false
} }
fn prev_sibling_element(&self) -> Option<DomRoot<Element>> { fn prev_sibling_element(&self) -> Option<Self> {
self.node self.node
.preceding_siblings() .preceding_siblings()
.filter_map(DomRoot::downcast) .filter_map(DomRoot::downcast)
.next() .next()
.map(SelectorWrapper::Owned)
} }
fn next_sibling_element(&self) -> Option<DomRoot<Element>> { fn next_sibling_element(&self) -> Option<Self> {
self.node self.node
.following_siblings() .following_siblings()
.filter_map(DomRoot::downcast) .filter_map(DomRoot::downcast)
.next() .next()
.map(SelectorWrapper::Owned)
} }
fn first_element_child(&self) -> Option<DomRoot<Element>> { fn first_element_child(&self) -> Option<Self> {
self.GetFirstElementChild() self.GetFirstElementChild().map(SelectorWrapper::Owned)
} }
fn attr_matches( fn attr_matches(
@ -4039,7 +4079,7 @@ impl SelectorsElement for DomRoot<Element> {
if !self_flags.is_empty() { if !self_flags.is_empty() {
#[allow(unsafe_code)] #[allow(unsafe_code)]
unsafe { unsafe {
Dom::from_ref(self.deref()) Dom::from_ref(&***self)
.to_layout() .to_layout()
.insert_selector_flags(self_flags); .insert_selector_flags(self_flags);
} }
@ -4051,7 +4091,7 @@ impl SelectorsElement for DomRoot<Element> {
if let Some(p) = self.parent_element() { if let Some(p) = self.parent_element() {
#[allow(unsafe_code)] #[allow(unsafe_code)]
unsafe { unsafe {
Dom::from_ref(p.deref()) Dom::from_ref(&**p)
.to_layout() .to_layout()
.insert_selector_flags(parent_flags); .insert_selector_flags(parent_flags);
} }

2
components/script/dom/htmlcanvaselement.rs
View file

@ -46,7 +46,7 @@ use crate::dom::bindings::inheritance::Castable;
use crate::dom::bindings::num::Finite; use crate::dom::bindings::num::Finite;
use crate::dom::bindings::refcounted::Trusted; use crate::dom::bindings::refcounted::Trusted;
use crate::dom::bindings::reflector::{DomGlobal, DomObject}; use crate::dom::bindings::reflector::{DomGlobal, DomObject};
use crate::dom::bindings::root::{Dom, DomRoot, LayoutDom}; use crate::dom::bindings::root::{Dom, DomRoot, LayoutDom, ToLayout};
use crate::dom::bindings::str::{DOMString, USVString}; use crate::dom::bindings::str::{DOMString, USVString};
use crate::dom::blob::Blob; use crate::dom::blob::Blob;
use crate::dom::canvasrenderingcontext2d::{ use crate::dom::canvasrenderingcontext2d::{

3
components/script/dom/messageport.rs
View file

@ -96,6 +96,7 @@ impl MessagePort {
} }
/// <https://html.spec.whatwg.org/multipage/#message-port-post-message-steps> /// <https://html.spec.whatwg.org/multipage/#message-port-post-message-steps>
#[allow(unsafe_code)]
fn post_message_impl( fn post_message_impl(
&self, &self,
cx: SafeJSContext, cx: SafeJSContext,
@ -115,7 +116,7 @@ impl MessagePort {
let ports = transfer let ports = transfer
.iter() .iter()
.filter_map(|&obj| root_from_object::<MessagePort>(obj, *cx).ok()); .filter_map(|&obj| unsafe { root_from_object::<MessagePort>(obj, *cx).ok() });
for port in ports { for port in ports {
// Step 2 // Step 2
if port.message_port_id() == self.message_port_id() { if port.message_port_id() == self.message_port_id() {

22
components/script/dom/node.rs
View file

@ -76,7 +76,7 @@ use crate::dom::bindings::inheritance::{
}; };
use crate::dom::bindings::refcounted::Trusted; use crate::dom::bindings::refcounted::Trusted;
use crate::dom::bindings::reflector::{reflect_dom_object_with_proto, DomObject, DomObjectWrap}; use crate::dom::bindings::reflector::{reflect_dom_object_with_proto, DomObject, DomObjectWrap};
use crate::dom::bindings::root::{Dom, DomRoot, DomSlice, LayoutDom, MutNullableDom}; use crate::dom::bindings::root::{Dom, DomRoot, DomSlice, LayoutDom, MutNullableDom, ToLayout};
use crate::dom::bindings::str::{DOMString, USVString}; use crate::dom::bindings::str::{DOMString, USVString};
use crate::dom::bindings::xmlname::namespace_from_domstring; use crate::dom::bindings::xmlname::namespace_from_domstring;
use crate::dom::characterdata::{CharacterData, LayoutCharacterDataHelpers}; use crate::dom::characterdata::{CharacterData, LayoutCharacterDataHelpers};
@ -85,7 +85,7 @@ use crate::dom::customelementregistry::{try_upgrade_element, CallbackReaction};
use crate::dom::document::{Document, DocumentSource, HasBrowsingContext, IsHTMLDocument}; use crate::dom::document::{Document, DocumentSource, HasBrowsingContext, IsHTMLDocument};
use crate::dom::documentfragment::DocumentFragment; use crate::dom::documentfragment::DocumentFragment;
use crate::dom::documenttype::DocumentType; use crate::dom::documenttype::DocumentType;
use crate::dom::element::{CustomElementCreationMode, Element, ElementCreator}; use crate::dom::element::{CustomElementCreationMode, Element, ElementCreator, SelectorWrapper};
use crate::dom::event::{Event, EventBubbles, EventCancelable}; use crate::dom::event::{Event, EventBubbles, EventCancelable};
use crate::dom::eventtarget::EventTarget; use crate::dom::eventtarget::EventTarget;
use crate::dom::htmlbodyelement::HTMLBodyElement; use crate::dom::htmlbodyelement::HTMLBodyElement;
@ -178,12 +178,6 @@ impl fmt::Debug for Node {
} }
} }
impl fmt::Debug for DomRoot<Node> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
(**self).fmt(f)
}
}
/// Flags for node items /// Flags for node items
#[derive(Clone, Copy, JSTraceable, MallocSizeOf)] #[derive(Clone, Copy, JSTraceable, MallocSizeOf)]
pub(crate) struct NodeFlags(u16); pub(crate) struct NodeFlags(u16);
@ -523,7 +517,11 @@ impl Iterator for QuerySelectorIterator {
MatchingForInvalidation::No, MatchingForInvalidation::No,
); );
if let Some(element) = DomRoot::downcast(node) { if let Some(element) = DomRoot::downcast(node) {
if matches_selector_list(selectors, &element, &mut ctx) { if matches_selector_list(
selectors,
&SelectorWrapper::Borrowed(&element),
&mut ctx,
) {
return Some(DomRoot::upcast(element)); return Some(DomRoot::upcast(element));
} }
} }
@ -1042,9 +1040,9 @@ impl Node {
let mut descendants = self.traverse_preorder(ShadowIncluding::No); let mut descendants = self.traverse_preorder(ShadowIncluding::No);
// Skip the root of the tree. // Skip the root of the tree.
assert!(&*descendants.next().unwrap() == self); assert!(&*descendants.next().unwrap() == self);
Ok(descendants Ok(descendants.filter_map(DomRoot::downcast).find(|element| {
.filter_map(DomRoot::downcast) matches_selector_list(&selectors, &SelectorWrapper::Borrowed(element), &mut ctx)
.find(|element| matches_selector_list(&selectors, element, &mut ctx))) }))
}, },
} }
} }

2
components/script/dom/webgl2renderingcontext.rs
View file

@ -40,7 +40,7 @@ use crate::dom::bindings::codegen::UnionTypes::{
}; };
use crate::dom::bindings::error::{ErrorResult, Fallible}; use crate::dom::bindings::error::{ErrorResult, Fallible};
use crate::dom::bindings::reflector::{reflect_dom_object, DomGlobal, Reflector}; use crate::dom::bindings::reflector::{reflect_dom_object, DomGlobal, Reflector};
use crate::dom::bindings::root::{Dom, DomRoot, LayoutDom, MutNullableDom}; use crate::dom::bindings::root::{Dom, DomRoot, LayoutDom, MutNullableDom, ToLayout};
use crate::dom::bindings::str::DOMString; use crate::dom::bindings::str::DOMString;
use crate::dom::globalscope::GlobalScope; use crate::dom::globalscope::GlobalScope;
use crate::dom::htmlcanvaselement::LayoutCanvasRenderingContextHelpers; use crate::dom::htmlcanvaselement::LayoutCanvasRenderingContextHelpers;

2
components/script/dom/workerglobalscope.rs
View file

@ -59,7 +59,7 @@ use crate::dom::workernavigator::WorkerNavigator;
use crate::fetch; use crate::fetch;
use crate::messaging::{CommonScriptMsg, ScriptEventLoopReceiver, ScriptEventLoopSender}; use crate::messaging::{CommonScriptMsg, ScriptEventLoopReceiver, ScriptEventLoopSender};
use crate::realms::{enter_realm, InRealm}; use crate::realms::{enter_realm, InRealm};
use crate::script_runtime::{CanGc, JSContext, Runtime}; use crate::script_runtime::{CanGc, JSContext, JSContextHelper, Runtime};
use crate::task::TaskCanceller; use crate::task::TaskCanceller;
use crate::timers::{IsInterval, TimerCallback}; use crate::timers::{IsInterval, TimerCallback};

47
components/script/script_runtime.rs
View file

@ -931,27 +931,21 @@ unsafe fn set_gc_zeal_options(cx: *mut RawJSContext) {
#[cfg(not(feature = "debugmozjs"))] #[cfg(not(feature = "debugmozjs"))]
unsafe fn set_gc_zeal_options(_: *mut RawJSContext) {} unsafe fn set_gc_zeal_options(_: *mut RawJSContext) {}
#[derive(Clone, Copy)] pub(crate) use script_bindings::script_runtime::JSContext;
#[repr(transparent)]
pub(crate) struct JSContext(*mut RawJSContext);
#[allow(unsafe_code)] /// Extra methods for the JSContext type defined in script_bindings, when
impl JSContext { /// the methods are only called by code in the script crate.
/// Create a new [`JSContext`] object from the given raw pointer. pub(crate) trait JSContextHelper {
/// fn get_reports(&self, path_seg: String) -> Vec<Report>;
/// # Safety
///
/// The `RawJSContext` argument must point to a valid `RawJSContext` in memory.
pub(crate) unsafe fn from_ptr(raw_js_context: *mut RawJSContext) -> Self {
JSContext(raw_js_context)
} }
impl JSContextHelper for JSContext {
#[allow(unsafe_code)] #[allow(unsafe_code)]
pub(crate) fn get_reports(&self, path_seg: String) -> Vec<Report> { fn get_reports(&self, path_seg: String) -> Vec<Report> {
SEEN_POINTERS.with(|pointers| pointers.borrow_mut().clear()); SEEN_POINTERS.with(|pointers| pointers.borrow_mut().clear());
let stats = unsafe { let stats = unsafe {
let mut stats = ::std::mem::zeroed(); let mut stats = ::std::mem::zeroed();
if !CollectServoSizes(self.0, &mut stats, Some(get_size)) { if !CollectServoSizes(**self, &mut stats, Some(get_size)) {
return vec![]; return vec![];
} }
stats stats
@ -1007,15 +1001,6 @@ impl JSContext {
} }
} }
#[allow(unsafe_code)]
impl Deref for JSContext {
type Target = *mut RawJSContext;
fn deref(&self) -> &Self::Target {
&self.0
}
}
pub(crate) struct StreamConsumer(*mut JSStreamConsumer); pub(crate) struct StreamConsumer(*mut JSStreamConsumer);
#[allow(unsafe_code)] #[allow(unsafe_code)]
@ -1171,18 +1156,4 @@ impl Runnable {
} }
} }
#[derive(Clone, Copy, Debug)] pub(crate) use script_bindings::script_runtime::CanGc;
/// A compile-time marker that there are operations that could trigger a JS garbage collection
/// operation within the current stack frame. It is trivially copyable, so it should be passed
/// as a function argument and reused when calling other functions whenever possible. Since it
/// is only meaningful within the current stack frame, it is impossible to move it to a different
/// thread or into a task that will execute asynchronously.
pub(crate) struct CanGc(std::marker::PhantomData<*mut ()>);
impl CanGc {
/// Create a new CanGc value, representing that a GC operation is possible within the
/// current stack frame.
pub(crate) fn note() -> CanGc {
CanGc(std::marker::PhantomData)
}
}

2
components/script/script_thread.rs
View file

@ -149,7 +149,7 @@ use crate::navigation::{InProgressLoad, NavigationListener};
use crate::realms::enter_realm; use crate::realms::enter_realm;
use crate::script_module::ScriptFetchOptions; use crate::script_module::ScriptFetchOptions;
use crate::script_runtime::{ use crate::script_runtime::{
CanGc, JSContext, Runtime, ScriptThreadEventCategory, ThreadSafeJSContext, CanGc, JSContext, JSContextHelper, Runtime, ScriptThreadEventCategory, ThreadSafeJSContext,
}; };
use crate::task_queue::TaskQueue; use crate::task_queue::TaskQueue;
use crate::task_source::{SendableTaskSource, TaskSourceName}; use crate::task_source::{SendableTaskSource, TaskSourceName};

13
components/script/dom/bindings/constant.rs → components/script_bindings/constant.rs
View file

@ -8,6 +8,7 @@ use std::ffi::CStr;
use js::jsapi::{JSPROP_ENUMERATE, JSPROP_PERMANENT, JSPROP_READONLY}; use js::jsapi::{JSPROP_ENUMERATE, JSPROP_PERMANENT, JSPROP_READONLY};
use js::jsval::{BooleanValue, DoubleValue, Int32Value, JSVal, NullValue, UInt32Value}; use js::jsval::{BooleanValue, DoubleValue, Int32Value, JSVal, NullValue, UInt32Value};
use js::rooted;
use js::rust::wrappers::JS_DefineProperty; use js::rust::wrappers::JS_DefineProperty;
use js::rust::HandleObject; use js::rust::HandleObject;
@ -15,17 +16,17 @@ use crate::script_runtime::JSContext;
/// Representation of an IDL constant. /// Representation of an IDL constant.
#[derive(Clone)] #[derive(Clone)]
pub(crate) struct ConstantSpec { pub struct ConstantSpec {
/// name of the constant. /// name of the constant.
pub(crate) name: &'static CStr, pub name: &'static CStr,
/// value of the constant. /// value of the constant.
pub(crate) value: ConstantVal, pub value: ConstantVal,
} }
/// Representation of an IDL constant value. /// Representation of an IDL constant value.
#[derive(Clone)] #[derive(Clone)]
#[allow(dead_code)] #[allow(dead_code)]
pub(crate) enum ConstantVal { pub enum ConstantVal {
/// `long` constant. /// `long` constant.
Int(i32), Int(i32),
/// `unsigned long` constant. /// `unsigned long` constant.
@ -40,7 +41,7 @@ pub(crate) enum ConstantVal {
impl ConstantSpec { impl ConstantSpec {
/// Returns a `JSVal` that represents the value of this `ConstantSpec`. /// Returns a `JSVal` that represents the value of this `ConstantSpec`.
pub(crate) fn get_value(&self) -> JSVal { pub fn get_value(&self) -> JSVal {
match self.value { match self.value {
ConstantVal::Null => NullValue(), ConstantVal::Null => NullValue(),
ConstantVal::Int(i) => Int32Value(i), ConstantVal::Int(i) => Int32Value(i),
@ -53,7 +54,7 @@ impl ConstantSpec {
/// Defines constants on `obj`. /// Defines constants on `obj`.
/// Fails on JSAPI failure. /// Fails on JSAPI failure.
pub(crate) fn define_constants(cx: JSContext, obj: HandleObject, constants: &[ConstantSpec]) { pub fn define_constants(cx: JSContext, obj: HandleObject, constants: &[ConstantSpec]) {
for spec in constants { for spec in constants {
rooted!(in(*cx) let value = spec.get_value()); rooted!(in(*cx) let value = spec.get_value());
unsafe { unsafe {

165
components/script_bindings/conversions.rs
View file

@ -8,18 +8,23 @@ use js::conversions::{
latin1_to_string, ConversionResult, FromJSValConvertible, ToJSValConvertible, latin1_to_string, ConversionResult, FromJSValConvertible, ToJSValConvertible,
}; };
use js::error::throw_type_error; use js::error::throw_type_error;
use js::glue::{GetProxyHandlerExtra, IsProxyHandlerFamily}; use js::glue::{
GetProxyHandlerExtra, GetProxyReservedSlot, IsProxyHandlerFamily, IsWrapper,
JS_GetReservedSlot, UnwrapObjectDynamic,
};
use js::jsapi::{ use js::jsapi::{
JSContext, JSObject, JSString, JS_DeprecatedStringHasLatin1Chars, JSContext, JSObject, JSString, JS_DeprecatedStringHasLatin1Chars,
JS_GetLatin1StringCharsAndLength, JS_GetTwoByteStringCharsAndLength, JS_NewStringCopyN, JS_GetLatin1StringCharsAndLength, JS_GetTwoByteStringCharsAndLength, JS_NewStringCopyN,
}; };
use js::jsval::{ObjectValue, StringValue}; use js::jsval::{ObjectValue, StringValue, UndefinedValue};
use js::rust::{ use js::rust::{
get_object_class, is_dom_class, maybe_wrap_value, HandleValue, MutableHandleValue, ToString, get_object_class, is_dom_class, is_dom_object, maybe_wrap_value, HandleValue,
MutableHandleValue, ToString,
}; };
use crate::inheritance::Castable; use crate::inheritance::Castable;
use crate::reflector::Reflector; use crate::reflector::{DomObject, Reflector};
use crate::root::DomRoot;
use crate::str::{ByteString, DOMString, USVString}; use crate::str::{ByteString, DOMString, USVString};
use crate::utils::{DOMClass, DOMJSClass}; use crate::utils::{DOMClass, DOMJSClass};
@ -199,6 +204,27 @@ impl ToJSValConvertible for Reflector {
} }
} }
impl<T: DomObject + IDLInterface> FromJSValConvertible for DomRoot<T> {
type Config = ();
unsafe fn from_jsval(
cx: *mut JSContext,
value: HandleValue,
_config: Self::Config,
) -> Result<ConversionResult<DomRoot<T>>, ()> {
Ok(match root_from_handlevalue(value, cx) {
Ok(result) => ConversionResult::Success(result),
Err(()) => ConversionResult::Failure("value is not an object".into()),
})
}
}
impl<T: DomObject> ToJSValConvertible for DomRoot<T> {
unsafe fn to_jsval(&self, cx: *mut JSContext, rval: MutableHandleValue) {
self.reflector().to_jsval(cx, rval);
}
}
/// Get the `DOMClass` from `obj`, or `Err(())` if `obj` is not a DOM object. /// Get the `DOMClass` from `obj`, or `Err(())` if `obj` is not a DOM object.
/// ///
/// # Safety /// # Safety
@ -230,3 +256,134 @@ pub unsafe fn is_dom_proxy(obj: *mut JSObject) -> bool {
((*clasp).flags & js::JSCLASS_IS_PROXY) != 0 && IsProxyHandlerFamily(obj) ((*clasp).flags & js::JSCLASS_IS_PROXY) != 0 && IsProxyHandlerFamily(obj)
} }
} }
/// The index of the slot wherein a pointer to the reflected DOM object is
/// stored for non-proxy bindings.
// We use slot 0 for holding the raw object. This is safe for both
// globals and non-globals.
pub const DOM_OBJECT_SLOT: u32 = 0;
/// Get the private pointer of a DOM object from a given reflector.
///
/// # Safety
/// obj must point to a valid non-null JS object.
pub unsafe fn private_from_object(obj: *mut JSObject) -> *const libc::c_void {
let mut value = UndefinedValue();
if is_dom_object(obj) {
JS_GetReservedSlot(obj, DOM_OBJECT_SLOT, &mut value);
} else {
debug_assert!(is_dom_proxy(obj));
GetProxyReservedSlot(obj, 0, &mut value);
};
if value.is_undefined() {
ptr::null()
} else {
value.to_private()
}
}
pub enum PrototypeCheck {
Derive(fn(&'static DOMClass) -> bool),
Depth { depth: usize, proto_id: u16 },
}
/// Get a `*const libc::c_void` for the given DOM object, unwrapping any
/// wrapper around it first, and checking if the object is of the correct type.
///
/// Returns Err(()) if `obj` is an opaque security wrapper or if the object is
/// not an object for a DOM object of the given type (as defined by the
/// proto_id and proto_depth).
///
/// # Safety
/// obj must point to a valid, non-null JS object.
/// cx must point to a valid, non-null JS context.
#[inline]
#[allow(clippy::result_unit_err)]
pub unsafe fn private_from_proto_check(
mut obj: *mut JSObject,
cx: *mut JSContext,
proto_check: PrototypeCheck,
) -> Result<*const libc::c_void, ()> {
let dom_class = get_dom_class(obj).or_else(|_| {
if IsWrapper(obj) {
trace!("found wrapper");
obj = UnwrapObjectDynamic(obj, cx, /* stopAtWindowProxy = */ false);
if obj.is_null() {
trace!("unwrapping security wrapper failed");
Err(())
} else {
assert!(!IsWrapper(obj));
trace!("unwrapped successfully");
get_dom_class(obj)
}
} else {
trace!("not a dom wrapper");
Err(())
}
})?;
let prototype_matches = match proto_check {
PrototypeCheck::Derive(f) => (f)(dom_class),
PrototypeCheck::Depth { depth, proto_id } => {
dom_class.interface_chain[depth] as u16 == proto_id
},
};
if prototype_matches {
trace!("good prototype");
Ok(private_from_object(obj))
} else {
trace!("bad prototype");
Err(())
}
}
/// Get a `*const T` for a DOM object accessible from a `JSObject`.
///
/// # Safety
/// obj must point to a valid, non-null JS object.
/// cx must point to a valid, non-null JS context.
#[allow(clippy::result_unit_err)]
pub unsafe fn native_from_object<T>(obj: *mut JSObject, cx: *mut JSContext) -> Result<*const T, ()>
where
T: DomObject + IDLInterface,
{
unsafe {
private_from_proto_check(obj, cx, PrototypeCheck::Derive(T::derives))
.map(|ptr| ptr as *const T)
}
}
/// Get a `DomRoot<T>` for the given DOM object, unwrapping any wrapper
/// around it first, and checking if the object is of the correct type.
///
/// Returns Err(()) if `obj` is an opaque security wrapper or if the object is
/// not a reflector for a DOM object of the given type (as defined by the
/// proto_id and proto_depth).
///
/// # Safety
/// obj must point to a valid, non-null JS object.
/// cx must point to a valid, non-null JS context.
#[allow(clippy::result_unit_err)]
pub unsafe fn root_from_object<T>(obj: *mut JSObject, cx: *mut JSContext) -> Result<DomRoot<T>, ()>
where
T: DomObject + IDLInterface,
{
native_from_object(obj, cx).map(|ptr| unsafe { DomRoot::from_ref(&*ptr) })
}
/// Get a `DomRoot<T>` for a DOM object accessible from a `HandleValue`.
/// Caller is responsible for throwing a JS exception if needed in case of error.
///
/// # Safety
/// cx must point to a valid, non-null JS context.
#[allow(clippy::result_unit_err)]
pub unsafe fn root_from_handlevalue<T>(v: HandleValue, cx: *mut JSContext) -> Result<DomRoot<T>, ()>
where
T: DomObject + IDLInterface,
{
if !v.get().is_object() {
return Err(());
}
root_from_object(v.get().to_object(), cx)
}

4
components/script_bindings/lib.rs
View file

@ -18,12 +18,14 @@ extern crate log;
extern crate malloc_size_of_derive; extern crate malloc_size_of_derive;
pub mod callback; pub mod callback;
pub mod constant;
pub mod conversions; pub mod conversions;
pub mod inheritance; pub mod inheritance;
pub mod reflector; pub mod reflector;
pub mod root;
pub mod script_runtime; pub mod script_runtime;
pub mod str; pub mod str;
mod trace; pub mod trace;
pub mod utils; pub mod utils;
#[allow(non_snake_case)] #[allow(non_snake_case)]

432
components/script_bindings/root.rs Normal file
View file

@ -0,0 +1,432 @@
/* 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::{Cell, UnsafeCell};
use std::hash::{Hash, Hasher};
use std::ops::Deref;
use std::{fmt, mem, ptr};
use js::gc::Traceable as JSTraceable;
use js::jsapi::{JSObject, JSTracer};
use malloc_size_of::{MallocSizeOf, MallocSizeOfOps};
use style::thread_state;
use crate::conversions::DerivedFrom;
use crate::inheritance::Castable;
use crate::reflector::{DomObject, MutDomObject, Reflector};
use crate::trace::trace_reflector;
/// A rooted value.
#[cfg_attr(crown, crown::unrooted_must_root_lint::allow_unrooted_interior)]
pub struct Root<T: StableTraceObject> {
/// The value to root.
value: T,
/// List that ensures correct dynamic root ordering
root_list: *const RootCollection,
}
impl<T> Root<T>
where
T: StableTraceObject + 'static,
{
/// Create a new stack-bounded root for the provided value.
/// It gives out references which cannot outlive this new `Root`.
///
/// # Safety
/// It must not outlive its associated `RootCollection`.
#[cfg_attr(crown, allow(crown::unrooted_must_root))]
pub unsafe fn new(value: T) -> Self {
unsafe fn add_to_root_list(object: *const dyn JSTraceable) -> *const RootCollection {
assert_in_script();
STACK_ROOTS.with(|root_list| {
let root_list = &*root_list.get().unwrap();
root_list.root(object);
root_list
})
}
let root_list = add_to_root_list(value.stable_trace_object());
Root { value, root_list }
}
}
/// `StableTraceObject` represents values that can be rooted through a stable address that will
/// not change for their whole lifetime.
/// It is an unsafe trait that requires implementors to ensure certain safety guarantees.
///
/// # Safety
///
/// Implementors of this trait must ensure that the `trace` method correctly accounts for all
/// owned and referenced objects, so that the garbage collector can accurately determine which
/// objects are still in use. Failing to adhere to this contract may result in undefined behavior,
/// such as use-after-free errors.
pub unsafe trait StableTraceObject {
/// Returns a stable trace object which address won't change for the whole
/// lifetime of the value.
fn stable_trace_object(&self) -> *const dyn JSTraceable;
}
unsafe impl<T> StableTraceObject for Dom<T>
where
T: DomObject,
{
fn stable_trace_object(&self) -> *const dyn JSTraceable {
// The JSTraceable impl for Reflector doesn't actually do anything,
// so we need this shenanigan to actually trace the reflector of the
// T pointer in Dom<T>.
#[cfg_attr(crown, allow(crown::unrooted_must_root))]
struct ReflectorStackRoot(Reflector);
unsafe impl JSTraceable for ReflectorStackRoot {
unsafe fn trace(&self, tracer: *mut JSTracer) {
trace_reflector(tracer, "on stack", &self.0);
}
}
unsafe { &*(self.reflector() as *const Reflector as *const ReflectorStackRoot) }
}
}
unsafe impl<T> StableTraceObject for MaybeUnreflectedDom<T>
where
T: DomObject,
{
fn stable_trace_object(&self) -> *const dyn JSTraceable {
// The JSTraceable impl for Reflector doesn't actually do anything,
// so we need this shenanigan to actually trace the reflector of the
// T pointer in Dom<T>.
#[cfg_attr(crown, allow(crown::unrooted_must_root))]
struct MaybeUnreflectedStackRoot<T>(T);
unsafe impl<T> JSTraceable for MaybeUnreflectedStackRoot<T>
where
T: DomObject,
{
unsafe fn trace(&self, tracer: *mut JSTracer) {
if self.0.reflector().get_jsobject().is_null() {
self.0.trace(tracer);
} else {
trace_reflector(tracer, "on stack", self.0.reflector());
}
}
}
unsafe { &*(self.ptr.as_ptr() as *const T as *const MaybeUnreflectedStackRoot<T>) }
}
}
impl<T> Deref for Root<T>
where
T: Deref + StableTraceObject,
{
type Target = <T as Deref>::Target;
fn deref(&self) -> &Self::Target {
assert_in_script();
&self.value
}
}
impl<T> Drop for Root<T>
where
T: StableTraceObject,
{
fn drop(&mut self) {
unsafe {
(*self.root_list).unroot(self.value.stable_trace_object());
}
}
}
impl<T: fmt::Debug + StableTraceObject> fmt::Debug for Root<T> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
self.value.fmt(f)
}
}
impl<T: fmt::Debug + DomObject> fmt::Debug for Dom<T> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
(**self).fmt(f)
}
}
/// A traced reference to a DOM object
///
/// This type is critical to making garbage collection work with the DOM,
/// but it is very dangerous; if garbage collection happens with a `Dom<T>`
/// on the stack, the `Dom<T>` can point to freed memory.
///
/// This should only be used as a field in other DOM objects.
#[cfg_attr(crown, crown::unrooted_must_root_lint::must_root)]
#[repr(transparent)]
pub struct Dom<T> {
ptr: ptr::NonNull<T>,
}
// Dom<T> is similar to Rc<T>, in that it's not always clear how to avoid double-counting.
// For now, we choose not to follow any such pointers.
impl<T> MallocSizeOf for Dom<T> {
fn size_of(&self, _ops: &mut MallocSizeOfOps) -> usize {
0
}
}
impl<T> PartialEq for Dom<T> {
fn eq(&self, other: &Dom<T>) -> bool {
self.ptr.as_ptr() == other.ptr.as_ptr()
}
}
impl<'a, T: DomObject> PartialEq<&'a T> for Dom<T> {
fn eq(&self, other: &&'a T) -> bool {
*self == Dom::from_ref(*other)
}
}
impl<T> Eq for Dom<T> {}
impl<T> Hash for Dom<T> {
fn hash<H: Hasher>(&self, state: &mut H) {
self.ptr.as_ptr().hash(state)
}
}
impl<T> Clone for Dom<T> {
#[inline]
#[cfg_attr(crown, allow(crown::unrooted_must_root))]
fn clone(&self) -> Self {
assert_in_script();
Dom { ptr: self.ptr }
}
}
impl<T: DomObject> Dom<T> {
/// Create a `Dom<T>` from a `&T`
#[cfg_attr(crown, allow(crown::unrooted_must_root))]
pub fn from_ref(obj: &T) -> Dom<T> {
assert_in_script();
Dom {
ptr: ptr::NonNull::from(obj),
}
}
/// Return a rooted version of this DOM object ([`DomRoot<T>`]) suitable for use on the stack.
pub fn as_rooted(&self) -> DomRoot<T> {
DomRoot::from_ref(self)
}
pub fn as_ptr(&self) -> *const T {
self.ptr.as_ptr()
}
}
impl<T: DomObject> Deref for Dom<T> {
type Target = T;
fn deref(&self) -> &T {
assert_in_script();
// We can only have &Dom<T> from a rooted thing, so it's safe to deref
// it to &T.
unsafe { &*self.ptr.as_ptr() }
}
}
unsafe impl<T: DomObject> JSTraceable for Dom<T> {
unsafe fn trace(&self, trc: *mut JSTracer) {
let trace_string;
let trace_info = if cfg!(debug_assertions) {
trace_string = format!("for {} on heap", ::std::any::type_name::<T>());
&trace_string[..]
} else {
"for DOM object on heap"
};
trace_reflector(trc, trace_info, (*self.ptr.as_ptr()).reflector());
}
}
/// A traced reference to a DOM object that may not be reflected yet.
#[cfg_attr(crown, crown::unrooted_must_root_lint::must_root)]
pub struct MaybeUnreflectedDom<T> {
ptr: ptr::NonNull<T>,
}
impl<T> MaybeUnreflectedDom<T>
where
T: DomObject,
{
/// Create a new MaybeUnreflectedDom value from the given boxed DOM object.
///
/// # Safety
/// TODO: unclear why this is marked unsafe.
#[cfg_attr(crown, allow(crown::unrooted_must_root))]
pub unsafe fn from_box(value: Box<T>) -> Self {
Self {
ptr: Box::leak(value).into(),
}
}
}
impl<T> Root<MaybeUnreflectedDom<T>>
where
T: DomObject,
{
pub fn as_ptr(&self) -> *const T {
self.value.ptr.as_ptr()
}
}
impl<T> Root<MaybeUnreflectedDom<T>>
where
T: MutDomObject,
{
/// Treat the given JS object as the reflector of this unreflected object.
///
/// # Safety
/// obj must point to a valid, non-null JS object.
pub unsafe fn reflect_with(self, obj: *mut JSObject) -> DomRoot<T> {
let ptr = self.as_ptr();
drop(self);
let root = DomRoot::from_ref(&*ptr);
root.init_reflector(obj);
root
}
}
/// A rooted reference to a DOM object.
pub type DomRoot<T> = Root<Dom<T>>;
impl<T: Castable> DomRoot<T> {
/// Cast a DOM object root upwards to one of the interfaces it derives from.
pub fn upcast<U>(root: DomRoot<T>) -> DomRoot<U>
where
U: Castable,
T: DerivedFrom<U>,
{
unsafe { mem::transmute::<DomRoot<T>, DomRoot<U>>(root) }
}
/// Cast a DOM object root downwards to one of the interfaces it might implement.
pub fn downcast<U>(root: DomRoot<T>) -> Option<DomRoot<U>>
where
U: DerivedFrom<T>,
{
if root.is::<U>() {
Some(unsafe { mem::transmute::<DomRoot<T>, DomRoot<U>>(root) })
} else {
None
}
}
}
impl<T: DomObject> DomRoot<T> {
/// Generate a new root from a reference
pub fn from_ref(unrooted: &T) -> DomRoot<T> {
unsafe { DomRoot::new(Dom::from_ref(unrooted)) }
}
/// Create a traced version of this rooted object.
///
/// # Safety
///
/// This should never be used to create on-stack values. Instead these values should always
/// end up as members of other DOM objects.
#[cfg_attr(crown, allow(crown::unrooted_must_root))]
pub fn as_traced(&self) -> Dom<T> {
Dom::from_ref(self)
}
}
impl<T> MallocSizeOf for DomRoot<T>
where
T: DomObject + MallocSizeOf,
{
fn size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
(**self).size_of(ops)
}
}
impl<T> PartialEq for DomRoot<T>
where
T: DomObject,
{
fn eq(&self, other: &Self) -> bool {
self.value == other.value
}
}
impl<T> Clone for DomRoot<T>
where
T: DomObject,
{
fn clone(&self) -> DomRoot<T> {
DomRoot::from_ref(self)
}
}
unsafe impl<T> JSTraceable for DomRoot<T>
where
T: DomObject,
{
unsafe fn trace(&self, _: *mut JSTracer) {
// Already traced.
}
}
/// A rooting mechanism for reflectors on the stack.
/// LIFO is not required.
///
/// See also [*Exact Stack Rooting - Storing a GCPointer on the CStack*][cstack].
///
/// [cstack]: https://developer.mozilla.org/en-US/docs/Mozilla/Projects/SpiderMonkey/Internals/GC/Exact_Stack_Rooting
pub struct RootCollection {
roots: UnsafeCell<Vec<*const dyn JSTraceable>>,
}
impl RootCollection {
/// Create an empty collection of roots
#[allow(clippy::new_without_default)]
pub fn new() -> RootCollection {
assert_in_script();
RootCollection {
roots: UnsafeCell::new(vec![]),
}
}
/// Starts tracking a trace object.
unsafe fn root(&self, object: *const dyn JSTraceable) {
assert_in_script();
(*self.roots.get()).push(object);
}
/// Stops tracking a trace object, asserting if it isn't found.
unsafe fn unroot(&self, object: *const dyn JSTraceable) {
assert_in_script();
let roots = &mut *self.roots.get();
match roots
.iter()
.rposition(|r| std::ptr::addr_eq(*r as *const (), object as *const ()))
{
Some(idx) => {
roots.remove(idx);
},
None => panic!("Can't remove a root that was never rooted!"),
}
}
}
thread_local!(pub static STACK_ROOTS: Cell<Option<*const RootCollection>> = const { Cell::new(None) });
/// SM Callback that traces the rooted reflectors
///
/// # Safety
/// tracer must point to a valid, non-null JS tracer object.
pub unsafe fn trace_roots(tracer: *mut JSTracer) {
trace!("tracing stack roots");
STACK_ROOTS.with(|collection| {
let collection = &*(*collection.get().unwrap()).roots.get();
for root in collection {
(**root).trace(tracer);
}
});
}
pub fn assert_in_script() {
debug_assert!(thread_state::get().is_script());
}

45
components/script_bindings/script_runtime.rs
View file

@ -3,6 +3,35 @@
* 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::cell::Cell; use std::cell::Cell;
use std::marker::PhantomData;
use std::ops::Deref;
use js::jsapi::JSContext as RawJSContext;
#[derive(Clone, Copy)]
#[repr(transparent)]
pub struct JSContext(*mut RawJSContext);
#[allow(unsafe_code)]
impl JSContext {
/// Create a new [`JSContext`] object from the given raw pointer.
///
/// # Safety
///
/// The `RawJSContext` argument must point to a valid `RawJSContext` in memory.
pub unsafe fn from_ptr(raw_js_context: *mut RawJSContext) -> Self {
JSContext(raw_js_context)
}
}
#[allow(unsafe_code)]
impl Deref for JSContext {
type Target = *mut RawJSContext;
fn deref(&self) -> &Self::Target {
&self.0
}
}
thread_local!( thread_local!(
static THREAD_ACTIVE: Cell<bool> = const { Cell::new(true) }; static THREAD_ACTIVE: Cell<bool> = const { Cell::new(true) };
@ -15,3 +44,19 @@ pub fn runtime_is_alive() -> bool {
pub fn mark_runtime_dead() { pub fn mark_runtime_dead() {
THREAD_ACTIVE.with(|t| t.set(false)); THREAD_ACTIVE.with(|t| t.set(false));
} }
#[derive(Clone, Copy, Debug)]
/// A compile-time marker that there are operations that could trigger a JS garbage collection
/// operation within the current stack frame. It is trivially copyable, so it should be passed
/// as a function argument and reused when calling other functions whenever possible. Since it
/// is only meaningful within the current stack frame, it is impossible to move it to a different
/// thread or into a task that will execute asynchronously.
pub struct CanGc(PhantomData<*mut ()>);
impl CanGc {
/// Create a new CanGc value, representing that a GC operation is possible within the
/// current stack frame.
pub fn note() -> CanGc {
CanGc(PhantomData)
}
}

29
components/script_bindings/trace.rs
View file

@ -2,8 +2,37 @@
* 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 js::glue::CallObjectTracer;
use js::jsapi::{GCTraceKindToAscii, Heap, JSObject, JSTracer, TraceKind};
use crate::reflector::Reflector;
use crate::str::{DOMString, USVString}; use crate::str::{DOMString, USVString};
/// Trace the `JSObject` held by `reflector`.
///
/// # Safety
/// tracer must point to a valid, non-null JS tracer.
#[cfg_attr(crown, allow(crown::unrooted_must_root))]
pub unsafe fn trace_reflector(tracer: *mut JSTracer, description: &str, reflector: &Reflector) {
trace!("tracing reflector {}", description);
trace_object(tracer, description, reflector.rootable())
}
/// Trace a `JSObject`.
///
/// # Safety
/// tracer must point to a valid, non-null JS tracer.
pub unsafe fn trace_object(tracer: *mut JSTracer, description: &str, obj: &Heap<*mut JSObject>) {
unsafe {
trace!("tracing {}", description);
CallObjectTracer(
tracer,
obj.ptr.get() as *mut _,
GCTraceKindToAscii(TraceKind::Object),
);
}
}
/// For use on non-jsmanaged types /// For use on non-jsmanaged types
/// Use #[derive(JSTraceable)] on JS managed types /// Use #[derive(JSTraceable)] on JS managed types
macro_rules! unsafe_no_jsmanaged_fields( macro_rules! unsafe_no_jsmanaged_fields(