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Move more bindings code to script_bindings (#35578)
* 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:
parent
54286229ea
commit
35f21e426b
23 changed files with 788 additions and 641 deletions
70
components/script_bindings/constant.rs
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70
components/script_bindings/constant.rs
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@ -0,0 +1,70 @@
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at https://mozilla.org/MPL/2.0/. */
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//! WebIDL constants.
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use std::ffi::CStr;
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use js::jsapi::{JSPROP_ENUMERATE, JSPROP_PERMANENT, JSPROP_READONLY};
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use js::jsval::{BooleanValue, DoubleValue, Int32Value, JSVal, NullValue, UInt32Value};
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use js::rooted;
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use js::rust::wrappers::JS_DefineProperty;
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use js::rust::HandleObject;
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use crate::script_runtime::JSContext;
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/// Representation of an IDL constant.
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#[derive(Clone)]
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pub struct ConstantSpec {
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/// name of the constant.
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pub name: &'static CStr,
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/// value of the constant.
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pub value: ConstantVal,
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}
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/// Representation of an IDL constant value.
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#[derive(Clone)]
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#[allow(dead_code)]
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pub enum ConstantVal {
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/// `long` constant.
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Int(i32),
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/// `unsigned long` constant.
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Uint(u32),
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/// `double` constant.
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Double(f64),
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/// `boolean` constant.
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Bool(bool),
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/// `null` constant.
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Null,
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}
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impl ConstantSpec {
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/// Returns a `JSVal` that represents the value of this `ConstantSpec`.
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pub fn get_value(&self) -> JSVal {
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match self.value {
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ConstantVal::Null => NullValue(),
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ConstantVal::Int(i) => Int32Value(i),
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ConstantVal::Uint(u) => UInt32Value(u),
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ConstantVal::Double(d) => DoubleValue(d),
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ConstantVal::Bool(b) => BooleanValue(b),
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}
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}
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}
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/// Defines constants on `obj`.
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/// Fails on JSAPI failure.
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pub fn define_constants(cx: JSContext, obj: HandleObject, constants: &[ConstantSpec]) {
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for spec in constants {
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rooted!(in(*cx) let value = spec.get_value());
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unsafe {
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assert!(JS_DefineProperty(
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*cx,
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obj,
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spec.name.as_ptr(),
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value.handle(),
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(JSPROP_ENUMERATE | JSPROP_READONLY | JSPROP_PERMANENT) as u32
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));
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}
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}
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}
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@ -8,18 +8,23 @@ use js::conversions::{
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latin1_to_string, ConversionResult, FromJSValConvertible, ToJSValConvertible,
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};
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use js::error::throw_type_error;
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use js::glue::{GetProxyHandlerExtra, IsProxyHandlerFamily};
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use js::glue::{
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GetProxyHandlerExtra, GetProxyReservedSlot, IsProxyHandlerFamily, IsWrapper,
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JS_GetReservedSlot, UnwrapObjectDynamic,
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};
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use js::jsapi::{
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JSContext, JSObject, JSString, JS_DeprecatedStringHasLatin1Chars,
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JS_GetLatin1StringCharsAndLength, JS_GetTwoByteStringCharsAndLength, JS_NewStringCopyN,
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};
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use js::jsval::{ObjectValue, StringValue};
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use js::jsval::{ObjectValue, StringValue, UndefinedValue};
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use js::rust::{
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get_object_class, is_dom_class, maybe_wrap_value, HandleValue, MutableHandleValue, ToString,
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get_object_class, is_dom_class, is_dom_object, maybe_wrap_value, HandleValue,
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MutableHandleValue, ToString,
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};
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use crate::inheritance::Castable;
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use crate::reflector::Reflector;
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use crate::reflector::{DomObject, Reflector};
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use crate::root::DomRoot;
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use crate::str::{ByteString, DOMString, USVString};
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use crate::utils::{DOMClass, DOMJSClass};
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@ -199,6 +204,27 @@ impl ToJSValConvertible for Reflector {
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}
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}
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impl<T: DomObject + IDLInterface> FromJSValConvertible for DomRoot<T> {
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type Config = ();
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unsafe fn from_jsval(
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cx: *mut JSContext,
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value: HandleValue,
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_config: Self::Config,
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) -> Result<ConversionResult<DomRoot<T>>, ()> {
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Ok(match root_from_handlevalue(value, cx) {
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Ok(result) => ConversionResult::Success(result),
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Err(()) => ConversionResult::Failure("value is not an object".into()),
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})
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}
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}
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impl<T: DomObject> ToJSValConvertible for DomRoot<T> {
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unsafe fn to_jsval(&self, cx: *mut JSContext, rval: MutableHandleValue) {
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self.reflector().to_jsval(cx, rval);
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}
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}
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/// Get the `DOMClass` from `obj`, or `Err(())` if `obj` is not a DOM object.
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///
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/// # Safety
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@ -230,3 +256,134 @@ pub unsafe fn is_dom_proxy(obj: *mut JSObject) -> bool {
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((*clasp).flags & js::JSCLASS_IS_PROXY) != 0 && IsProxyHandlerFamily(obj)
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}
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}
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/// The index of the slot wherein a pointer to the reflected DOM object is
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/// stored for non-proxy bindings.
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// We use slot 0 for holding the raw object. This is safe for both
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// globals and non-globals.
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pub const DOM_OBJECT_SLOT: u32 = 0;
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/// Get the private pointer of a DOM object from a given reflector.
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///
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/// # Safety
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/// obj must point to a valid non-null JS object.
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pub unsafe fn private_from_object(obj: *mut JSObject) -> *const libc::c_void {
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let mut value = UndefinedValue();
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if is_dom_object(obj) {
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JS_GetReservedSlot(obj, DOM_OBJECT_SLOT, &mut value);
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} else {
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debug_assert!(is_dom_proxy(obj));
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GetProxyReservedSlot(obj, 0, &mut value);
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};
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if value.is_undefined() {
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ptr::null()
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} else {
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value.to_private()
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}
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}
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pub enum PrototypeCheck {
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Derive(fn(&'static DOMClass) -> bool),
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Depth { depth: usize, proto_id: u16 },
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}
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/// Get a `*const libc::c_void` for the given DOM object, unwrapping any
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/// wrapper around it first, and checking if the object is of the correct type.
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///
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/// Returns Err(()) if `obj` is an opaque security wrapper or if the object is
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/// not an object for a DOM object of the given type (as defined by the
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/// proto_id and proto_depth).
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///
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/// # Safety
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/// obj must point to a valid, non-null JS object.
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/// cx must point to a valid, non-null JS context.
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#[inline]
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#[allow(clippy::result_unit_err)]
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pub unsafe fn private_from_proto_check(
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mut obj: *mut JSObject,
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cx: *mut JSContext,
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proto_check: PrototypeCheck,
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) -> Result<*const libc::c_void, ()> {
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let dom_class = get_dom_class(obj).or_else(|_| {
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if IsWrapper(obj) {
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trace!("found wrapper");
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obj = UnwrapObjectDynamic(obj, cx, /* stopAtWindowProxy = */ false);
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if obj.is_null() {
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trace!("unwrapping security wrapper failed");
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Err(())
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} else {
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assert!(!IsWrapper(obj));
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trace!("unwrapped successfully");
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get_dom_class(obj)
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}
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} else {
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trace!("not a dom wrapper");
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Err(())
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}
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})?;
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let prototype_matches = match proto_check {
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PrototypeCheck::Derive(f) => (f)(dom_class),
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PrototypeCheck::Depth { depth, proto_id } => {
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dom_class.interface_chain[depth] as u16 == proto_id
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},
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};
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if prototype_matches {
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trace!("good prototype");
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Ok(private_from_object(obj))
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} else {
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trace!("bad prototype");
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Err(())
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}
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}
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/// Get a `*const T` for a DOM object accessible from a `JSObject`.
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///
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/// # Safety
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/// obj must point to a valid, non-null JS object.
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/// cx must point to a valid, non-null JS context.
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#[allow(clippy::result_unit_err)]
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pub unsafe fn native_from_object<T>(obj: *mut JSObject, cx: *mut JSContext) -> Result<*const T, ()>
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where
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T: DomObject + IDLInterface,
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{
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unsafe {
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private_from_proto_check(obj, cx, PrototypeCheck::Derive(T::derives))
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.map(|ptr| ptr as *const T)
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}
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}
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/// Get a `DomRoot<T>` for the given DOM object, unwrapping any wrapper
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/// around it first, and checking if the object is of the correct type.
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///
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/// Returns Err(()) if `obj` is an opaque security wrapper or if the object is
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/// not a reflector for a DOM object of the given type (as defined by the
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/// proto_id and proto_depth).
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///
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/// # Safety
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/// obj must point to a valid, non-null JS object.
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/// cx must point to a valid, non-null JS context.
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#[allow(clippy::result_unit_err)]
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pub unsafe fn root_from_object<T>(obj: *mut JSObject, cx: *mut JSContext) -> Result<DomRoot<T>, ()>
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where
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T: DomObject + IDLInterface,
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{
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native_from_object(obj, cx).map(|ptr| unsafe { DomRoot::from_ref(&*ptr) })
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}
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/// Get a `DomRoot<T>` for a DOM object accessible from a `HandleValue`.
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/// Caller is responsible for throwing a JS exception if needed in case of error.
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///
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/// # Safety
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/// cx must point to a valid, non-null JS context.
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#[allow(clippy::result_unit_err)]
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pub unsafe fn root_from_handlevalue<T>(v: HandleValue, cx: *mut JSContext) -> Result<DomRoot<T>, ()>
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where
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T: DomObject + IDLInterface,
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{
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if !v.get().is_object() {
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return Err(());
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}
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root_from_object(v.get().to_object(), cx)
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}
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@ -18,12 +18,14 @@ extern crate log;
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extern crate malloc_size_of_derive;
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pub mod callback;
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pub mod constant;
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pub mod conversions;
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pub mod inheritance;
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pub mod reflector;
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pub mod root;
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pub mod script_runtime;
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pub mod str;
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mod trace;
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pub mod trace;
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pub mod utils;
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#[allow(non_snake_case)]
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432
components/script_bindings/root.rs
Normal file
432
components/script_bindings/root.rs
Normal file
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at https://mozilla.org/MPL/2.0/. */
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use std::cell::{Cell, UnsafeCell};
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use std::hash::{Hash, Hasher};
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use std::ops::Deref;
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use std::{fmt, mem, ptr};
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use js::gc::Traceable as JSTraceable;
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use js::jsapi::{JSObject, JSTracer};
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use malloc_size_of::{MallocSizeOf, MallocSizeOfOps};
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use style::thread_state;
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use crate::conversions::DerivedFrom;
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use crate::inheritance::Castable;
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use crate::reflector::{DomObject, MutDomObject, Reflector};
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use crate::trace::trace_reflector;
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/// A rooted value.
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#[cfg_attr(crown, crown::unrooted_must_root_lint::allow_unrooted_interior)]
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pub struct Root<T: StableTraceObject> {
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/// The value to root.
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value: T,
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/// List that ensures correct dynamic root ordering
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root_list: *const RootCollection,
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}
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impl<T> Root<T>
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where
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T: StableTraceObject + 'static,
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{
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/// Create a new stack-bounded root for the provided value.
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/// It gives out references which cannot outlive this new `Root`.
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///
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/// # Safety
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/// It must not outlive its associated `RootCollection`.
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#[cfg_attr(crown, allow(crown::unrooted_must_root))]
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pub unsafe fn new(value: T) -> Self {
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unsafe fn add_to_root_list(object: *const dyn JSTraceable) -> *const RootCollection {
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assert_in_script();
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STACK_ROOTS.with(|root_list| {
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let root_list = &*root_list.get().unwrap();
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root_list.root(object);
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root_list
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})
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}
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let root_list = add_to_root_list(value.stable_trace_object());
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Root { value, root_list }
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}
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}
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/// `StableTraceObject` represents values that can be rooted through a stable address that will
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/// not change for their whole lifetime.
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/// It is an unsafe trait that requires implementors to ensure certain safety guarantees.
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///
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/// # Safety
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///
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/// Implementors of this trait must ensure that the `trace` method correctly accounts for all
|
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/// owned and referenced objects, so that the garbage collector can accurately determine which
|
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/// objects are still in use. Failing to adhere to this contract may result in undefined behavior,
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/// such as use-after-free errors.
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pub unsafe trait StableTraceObject {
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/// Returns a stable trace object which address won't change for the whole
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/// lifetime of the value.
|
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fn stable_trace_object(&self) -> *const dyn JSTraceable;
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}
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unsafe impl<T> StableTraceObject for Dom<T>
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where
|
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T: DomObject,
|
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{
|
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fn stable_trace_object(&self) -> *const dyn JSTraceable {
|
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// The JSTraceable impl for Reflector doesn't actually do anything,
|
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// so we need this shenanigan to actually trace the reflector of the
|
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// T pointer in Dom<T>.
|
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#[cfg_attr(crown, allow(crown::unrooted_must_root))]
|
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struct ReflectorStackRoot(Reflector);
|
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unsafe impl JSTraceable for ReflectorStackRoot {
|
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unsafe fn trace(&self, tracer: *mut JSTracer) {
|
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trace_reflector(tracer, "on stack", &self.0);
|
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}
|
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}
|
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unsafe { &*(self.reflector() as *const Reflector as *const ReflectorStackRoot) }
|
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}
|
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}
|
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|
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unsafe impl<T> StableTraceObject for MaybeUnreflectedDom<T>
|
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where
|
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T: DomObject,
|
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{
|
||||
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))]
|
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struct MaybeUnreflectedStackRoot<T>(T);
|
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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() {
|
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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());
|
||||
}
|
|
@ -3,6 +3,35 @@
|
|||
* file, You can obtain one at https://mozilla.org/MPL/2.0/. */
|
||||
|
||||
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!(
|
||||
static THREAD_ACTIVE: Cell<bool> = const { Cell::new(true) };
|
||||
|
@ -15,3 +44,19 @@ pub fn runtime_is_alive() -> bool {
|
|||
pub fn mark_runtime_dead() {
|
||||
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)
|
||||
}
|
||||
}
|
||||
|
|
|
@ -2,8 +2,37 @@
|
|||
* 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 js::glue::CallObjectTracer;
|
||||
use js::jsapi::{GCTraceKindToAscii, Heap, JSObject, JSTracer, TraceKind};
|
||||
|
||||
use crate::reflector::Reflector;
|
||||
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
|
||||
/// Use #[derive(JSTraceable)] on JS managed types
|
||||
macro_rules! unsafe_no_jsmanaged_fields(
|
||||
|
|
Loading…
Add table
Add a link
Reference in a new issue