servo/components/script/dom/bindings/utils.rs
Josh Matthews c94d909a86
script: Limit public exports. (#34915)
* script: Restrict reexport visibility of DOM types.

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

* script: Mass pub->pub(crate) conversion.

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

* script: Hide existing dead code warnings.

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

* Formatting.

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

* Fix clippy warnings.

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

* Formatting.

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

* Fix unit tests.

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

* Fix clippy.

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

* More formatting.

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

---------

Signed-off-by: Josh Matthews <josh@joshmatthews.net>
2025-01-10 08:19:19 +00:00

698 lines
22 KiB
Rust

/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at https://mozilla.org/MPL/2.0/. */
//! Various utilities to glue JavaScript and the DOM implementation together.
use std::ffi::CString;
use std::os::raw::{c_char, c_void};
use std::ptr::NonNull;
use std::sync::OnceLock;
use std::{ptr, slice, str};
use js::conversions::ToJSValConvertible;
use js::glue::{
CallJitGetterOp, CallJitMethodOp, CallJitSetterOp, IsWrapper, JS_GetReservedSlot,
UnwrapObjectDynamic, UnwrapObjectStatic, RUST_FUNCTION_VALUE_TO_JITINFO,
};
use js::jsapi::{
AtomToLinearString, CallArgs, DOMCallbacks, ExceptionStackBehavior, GetLinearStringCharAt,
GetLinearStringLength, GetNonCCWObjectGlobal, HandleId as RawHandleId,
HandleObject as RawHandleObject, Heap, JSAtom, JSContext, JSJitInfo, JSObject, JSTracer,
JS_ClearPendingException, JS_DeprecatedStringHasLatin1Chars, JS_EnumerateStandardClasses,
JS_FreezeObject, JS_GetLatin1StringCharsAndLength, JS_IsExceptionPending, JS_IsGlobalObject,
JS_ResolveStandardClass, MutableHandleIdVector as RawMutableHandleIdVector,
MutableHandleValue as RawMutableHandleValue, ObjectOpResult, StringIsArrayIndex,
};
use js::jsval::{JSVal, UndefinedValue};
use js::rust::wrappers::{
CallOriginalPromiseReject, JS_DeletePropertyById, JS_ForwardGetPropertyTo,
JS_GetPendingException, JS_GetProperty, JS_GetPrototype, JS_HasProperty, JS_HasPropertyById,
JS_SetPendingException, JS_SetProperty,
};
use js::rust::{
get_object_class, is_dom_class, GCMethods, Handle, HandleId, HandleObject, HandleValue,
MutableHandleValue, ToString,
};
use js::JS_CALLEE;
use malloc_size_of::MallocSizeOfOps;
use crate::dom::bindings::codegen::PrototypeList::{MAX_PROTO_CHAIN_LENGTH, PROTO_OR_IFACE_LENGTH};
use crate::dom::bindings::codegen::{InterfaceObjectMap, PrototypeList};
use crate::dom::bindings::conversions::{
jsstring_to_str, private_from_proto_check, PrototypeCheck,
};
use crate::dom::bindings::error::throw_invalid_this;
use crate::dom::bindings::inheritance::TopTypeId;
use crate::dom::bindings::str::DOMString;
use crate::dom::bindings::trace::trace_object;
use crate::dom::windowproxy::WindowProxyHandler;
use crate::script_runtime::JSContext as SafeJSContext;
/// A OnceLock wrapping a type that is not considered threadsafe by the Rust compiler, but
/// will be used in a threadsafe manner (it will not be mutated, after being initialized).
///
/// This is needed to allow using JS API types (which usually involve raw pointers) in static initializers,
/// when Servo guarantees through the use of OnceLock that only one thread will ever initialize
/// the value.
pub(crate) struct ThreadUnsafeOnceLock<T>(OnceLock<T>);
impl<T> ThreadUnsafeOnceLock<T> {
pub(crate) const fn new() -> Self {
Self(OnceLock::new())
}
/// Initialize the value inside this lock. Panics if the lock has been previously initialized.
pub(crate) fn set(&self, val: T) {
assert!(self.0.set(val).is_ok());
}
/// Get a reference to the value inside this lock. Panics if the lock has not been initialized.
///
/// SAFETY:
/// The caller must ensure that it does not mutate value contained inside this lock
/// (using interior mutability).
pub(crate) unsafe fn get(&self) -> &T {
self.0.get().unwrap()
}
}
unsafe impl<T> Sync for ThreadUnsafeOnceLock<T> {}
unsafe impl<T> Send for ThreadUnsafeOnceLock<T> {}
#[derive(JSTraceable, MallocSizeOf)]
/// Static data associated with a global object.
pub(crate) struct GlobalStaticData {
#[ignore_malloc_size_of = "WindowProxyHandler does not properly implement it anyway"]
/// The WindowProxy proxy handler for this global.
pub(crate) windowproxy_handler: &'static WindowProxyHandler,
}
impl GlobalStaticData {
/// Creates a new GlobalStaticData.
pub(crate) fn new() -> GlobalStaticData {
GlobalStaticData {
windowproxy_handler: WindowProxyHandler::proxy_handler(),
}
}
}
/// The index of the slot where the object holder of that interface's
/// unforgeable members are defined.
pub(crate) const DOM_PROTO_UNFORGEABLE_HOLDER_SLOT: u32 = 0;
/// The index of the slot that contains a reference to the ProtoOrIfaceArray.
// All DOM globals must have a slot at DOM_PROTOTYPE_SLOT.
pub(crate) const DOM_PROTOTYPE_SLOT: u32 = js::JSCLASS_GLOBAL_SLOT_COUNT;
/// The flag set on the `JSClass`es for DOM global objects.
// NOTE: This is baked into the Ion JIT as 0 in codegen for LGetDOMProperty and
// LSetDOMProperty. Those constants need to be changed accordingly if this value
// changes.
pub(crate) const JSCLASS_DOM_GLOBAL: u32 = js::JSCLASS_USERBIT1;
/// The struct that holds inheritance information for DOM object reflectors.
#[derive(Clone, Copy)]
pub(crate) struct DOMClass {
/// A list of interfaces that this object implements, in order of decreasing
/// derivedness.
pub(crate) interface_chain: [PrototypeList::ID; MAX_PROTO_CHAIN_LENGTH],
/// The last valid index of `interface_chain`.
pub(crate) depth: u8,
/// The type ID of that interface.
pub(crate) type_id: TopTypeId,
/// The MallocSizeOf function wrapper for that interface.
pub(crate) malloc_size_of: unsafe fn(ops: &mut MallocSizeOfOps, *const c_void) -> usize,
/// The `Globals` flag for this global interface, if any.
pub(crate) global: InterfaceObjectMap::Globals,
}
unsafe impl Sync for DOMClass {}
/// The JSClass used for DOM object reflectors.
#[derive(Copy)]
#[repr(C)]
pub(crate) struct DOMJSClass {
/// The actual JSClass.
pub(crate) base: js::jsapi::JSClass,
/// Associated data for DOM object reflectors.
pub(crate) dom_class: DOMClass,
}
impl Clone for DOMJSClass {
fn clone(&self) -> DOMJSClass {
*self
}
}
unsafe impl Sync for DOMJSClass {}
/// Returns a JSVal representing the frozen JavaScript array
pub(crate) fn to_frozen_array<T: ToJSValConvertible>(
convertibles: &[T],
cx: SafeJSContext,
rval: MutableHandleValue,
) {
unsafe { convertibles.to_jsval(*cx, rval) };
rooted!(in(*cx) let obj = rval.to_object());
unsafe { JS_FreezeObject(*cx, RawHandleObject::from(obj.handle())) };
}
/// Returns the ProtoOrIfaceArray for the given global object.
/// Fails if `global` is not a DOM global object.
pub(crate) fn get_proto_or_iface_array(global: *mut JSObject) -> *mut ProtoOrIfaceArray {
unsafe {
assert_ne!(((*get_object_class(global)).flags & JSCLASS_DOM_GLOBAL), 0);
let mut slot = UndefinedValue();
JS_GetReservedSlot(global, DOM_PROTOTYPE_SLOT, &mut slot);
slot.to_private() as *mut ProtoOrIfaceArray
}
}
/// An array of *mut JSObject of size PROTO_OR_IFACE_LENGTH.
pub(crate) type ProtoOrIfaceArray = [*mut JSObject; PROTO_OR_IFACE_LENGTH];
/// Gets the property `id` on `proxy`'s prototype. If it exists, `*found` is
/// set to true and `*vp` to the value, otherwise `*found` is set to false.
///
/// Returns false on JSAPI failure.
pub(crate) unsafe fn get_property_on_prototype(
cx: *mut JSContext,
proxy: HandleObject,
receiver: HandleValue,
id: HandleId,
found: *mut bool,
vp: MutableHandleValue,
) -> bool {
rooted!(in(cx) let mut proto = ptr::null_mut::<JSObject>());
if !JS_GetPrototype(cx, proxy, proto.handle_mut()) || proto.is_null() {
*found = false;
return true;
}
let mut has_property = false;
if !JS_HasPropertyById(cx, proto.handle(), id, &mut has_property) {
return false;
}
*found = has_property;
if !has_property {
return true;
}
JS_ForwardGetPropertyTo(cx, proto.handle(), id, receiver, vp)
}
/// Get an array index from the given `jsid`. Returns `None` if the given
/// `jsid` is not an integer.
pub(crate) unsafe fn get_array_index_from_id(_cx: *mut JSContext, id: HandleId) -> Option<u32> {
let raw_id = *id;
if raw_id.is_int() {
return Some(raw_id.to_int() as u32);
}
if raw_id.is_void() || !raw_id.is_string() {
return None;
}
let atom = raw_id.to_string() as *mut JSAtom;
let s = AtomToLinearString(atom);
if GetLinearStringLength(s) == 0 {
return None;
}
let chars = [GetLinearStringCharAt(s, 0)];
let first_char = char::decode_utf16(chars.iter().cloned())
.next()
.map_or('\0', |r| r.unwrap_or('\0'));
if !first_char.is_ascii_lowercase() {
return None;
}
let mut i = 0;
if StringIsArrayIndex(s, &mut i) {
Some(i)
} else {
None
}
/*let s = jsstr_to_string(cx, RUST_JSID_TO_STRING(raw_id));
if s.len() == 0 {
return None;
}
let first = s.chars().next().unwrap();
if first.is_ascii_lowercase() {
return None;
}
let mut i: u32 = 0;
let is_array = if s.is_ascii() {
let chars = s.as_bytes();
StringIsArrayIndex1(chars.as_ptr() as *const _, chars.len() as u32, &mut i)
} else {
let chars = s.encode_utf16().collect::<Vec<u16>>();
let slice = chars.as_slice();
StringIsArrayIndex2(slice.as_ptr(), chars.len() as u32, &mut i)
};
if is_array {
Some(i)
} else {
None
}*/
}
/// Find the enum equivelent of a string given by `v` in `pairs`.
/// Returns `Err(())` on JSAPI failure (there is a pending exception), and
/// `Ok((None, value))` if there was no matching string.
pub(crate) unsafe fn find_enum_value<'a, T>(
cx: *mut JSContext,
v: HandleValue,
pairs: &'a [(&'static str, T)],
) -> Result<(Option<&'a T>, DOMString), ()> {
match ptr::NonNull::new(ToString(cx, v)) {
Some(jsstr) => {
let search = jsstring_to_str(cx, jsstr);
Ok((
pairs
.iter()
.find(|&&(key, _)| search == *key)
.map(|(_, ev)| ev),
search,
))
},
None => Err(()),
}
}
/// Returns wether `obj` is a platform object using dynamic unwrap
/// <https://heycam.github.io/webidl/#dfn-platform-object>
#[allow(dead_code)]
pub(crate) fn is_platform_object_dynamic(obj: *mut JSObject, cx: *mut JSContext) -> bool {
is_platform_object(obj, &|o| unsafe {
UnwrapObjectDynamic(o, cx, /* stopAtWindowProxy = */ false)
})
}
/// Returns wether `obj` is a platform object using static unwrap
/// <https://heycam.github.io/webidl/#dfn-platform-object>
pub(crate) fn is_platform_object_static(obj: *mut JSObject) -> bool {
is_platform_object(obj, &|o| unsafe { UnwrapObjectStatic(o) })
}
fn is_platform_object(
obj: *mut JSObject,
unwrap_obj: &dyn Fn(*mut JSObject) -> *mut JSObject,
) -> bool {
unsafe {
// Fast-path the common case
let mut clasp = get_object_class(obj);
if is_dom_class(&*clasp) {
return true;
}
// Now for simplicity check for security wrappers before anything else
if IsWrapper(obj) {
let unwrapped_obj = unwrap_obj(obj);
if unwrapped_obj.is_null() {
return false;
}
clasp = get_object_class(obj);
}
// TODO also check if JS_IsArrayBufferObject
is_dom_class(&*clasp)
}
}
/// Get the property with name `property` from `object`.
/// Returns `Err(())` on JSAPI failure (there is a pending exception), and
/// `Ok(false)` if there was no property with the given name.
pub(crate) fn get_dictionary_property(
cx: *mut JSContext,
object: HandleObject,
property: &str,
rval: MutableHandleValue,
) -> Result<bool, ()> {
fn has_property(
cx: *mut JSContext,
object: HandleObject,
property: &CString,
found: &mut bool,
) -> bool {
unsafe { JS_HasProperty(cx, object, property.as_ptr(), found) }
}
fn get_property(
cx: *mut JSContext,
object: HandleObject,
property: &CString,
value: MutableHandleValue,
) -> bool {
unsafe { JS_GetProperty(cx, object, property.as_ptr(), value) }
}
let property = CString::new(property).unwrap();
if object.get().is_null() {
return Ok(false);
}
let mut found = false;
if !has_property(cx, object, &property, &mut found) {
return Err(());
}
if !found {
return Ok(false);
}
if !get_property(cx, object, &property, rval) {
return Err(());
}
Ok(true)
}
/// Set the property with name `property` from `object`.
/// Returns `Err(())` on JSAPI failure, or null object,
/// and Ok(()) otherwise
pub(crate) fn set_dictionary_property(
cx: *mut JSContext,
object: HandleObject,
property: &str,
value: HandleValue,
) -> Result<(), ()> {
if object.get().is_null() {
return Err(());
}
let property = CString::new(property).unwrap();
unsafe {
if !JS_SetProperty(cx, object, property.as_ptr(), value) {
return Err(());
}
}
Ok(())
}
/// Returns whether `proxy` has a property `id` on its prototype.
pub(crate) unsafe fn has_property_on_prototype(
cx: *mut JSContext,
proxy: HandleObject,
id: HandleId,
found: &mut bool,
) -> bool {
rooted!(in(cx) let mut proto = ptr::null_mut::<JSObject>());
if !JS_GetPrototype(cx, proxy, proto.handle_mut()) {
return false;
}
assert!(!proto.is_null());
JS_HasPropertyById(cx, proto.handle(), id, found)
}
/// Drop the resources held by reserved slots of a global object
pub(crate) unsafe fn finalize_global(obj: *mut JSObject) {
let protolist = get_proto_or_iface_array(obj);
let list = (*protolist).as_mut_ptr();
for idx in 0..PROTO_OR_IFACE_LENGTH as isize {
let entry = list.offset(idx);
let value = *entry;
<*mut JSObject>::post_barrier(entry, value, ptr::null_mut());
}
let _: Box<ProtoOrIfaceArray> = Box::from_raw(protolist);
}
/// Trace the resources held by reserved slots of a global object
pub(crate) unsafe fn trace_global(tracer: *mut JSTracer, obj: *mut JSObject) {
let array = get_proto_or_iface_array(obj);
for proto in (*array).iter() {
if !proto.is_null() {
trace_object(
tracer,
"prototype",
&*(proto as *const *mut JSObject as *const Heap<*mut JSObject>),
);
}
}
}
/// Enumerate lazy properties of a global object.
pub(crate) unsafe extern "C" fn enumerate_global(
cx: *mut JSContext,
obj: RawHandleObject,
_props: RawMutableHandleIdVector,
_enumerable_only: bool,
) -> bool {
assert!(JS_IsGlobalObject(obj.get()));
if !JS_EnumerateStandardClasses(cx, obj) {
return false;
}
for init_fun in InterfaceObjectMap::MAP.values() {
init_fun(SafeJSContext::from_ptr(cx), Handle::from_raw(obj));
}
true
}
/// Resolve a lazy global property, for interface objects and named constructors.
pub(crate) unsafe extern "C" fn resolve_global(
cx: *mut JSContext,
obj: RawHandleObject,
id: RawHandleId,
rval: *mut bool,
) -> bool {
assert!(JS_IsGlobalObject(obj.get()));
if !JS_ResolveStandardClass(cx, obj, id, rval) {
return false;
}
if *rval {
return true;
}
if !id.is_string() {
*rval = false;
return true;
}
let string = id.to_string();
if !JS_DeprecatedStringHasLatin1Chars(string) {
*rval = false;
return true;
}
let mut length = 0;
let ptr = JS_GetLatin1StringCharsAndLength(cx, ptr::null(), string, &mut length);
assert!(!ptr.is_null());
let bytes = slice::from_raw_parts(ptr, length);
if let Some(init_fun) = InterfaceObjectMap::MAP.get(bytes) {
init_fun(SafeJSContext::from_ptr(cx), Handle::from_raw(obj));
*rval = true;
} else {
*rval = false;
}
true
}
/// Deletes the property `id` from `object`.
pub(crate) unsafe fn delete_property_by_id(
cx: *mut JSContext,
object: HandleObject,
id: HandleId,
bp: *mut ObjectOpResult,
) -> bool {
JS_DeletePropertyById(cx, object, id, bp)
}
unsafe fn generic_call<const EXCEPTION_TO_REJECTION: bool>(
cx: *mut JSContext,
argc: libc::c_uint,
vp: *mut JSVal,
is_lenient: bool,
call: unsafe extern "C" fn(
*const JSJitInfo,
*mut JSContext,
RawHandleObject,
*mut libc::c_void,
u32,
*mut JSVal,
) -> bool,
) -> bool {
let args = CallArgs::from_vp(vp, argc);
let info = RUST_FUNCTION_VALUE_TO_JITINFO(JS_CALLEE(cx, vp));
let proto_id = (*info).__bindgen_anon_2.protoID;
let thisobj = args.thisv();
if !thisobj.get().is_null_or_undefined() && !thisobj.get().is_object() {
throw_invalid_this(cx, proto_id);
return if EXCEPTION_TO_REJECTION {
exception_to_promise(cx, args.rval())
} else {
false
};
}
rooted!(in(cx) let obj = if thisobj.get().is_object() {
thisobj.get().to_object()
} else {
GetNonCCWObjectGlobal(JS_CALLEE(cx, vp).to_object_or_null())
});
let depth = (*info).__bindgen_anon_3.depth as usize;
let proto_check = PrototypeCheck::Depth { depth, proto_id };
let this = match private_from_proto_check(obj.get(), cx, proto_check) {
Ok(val) => val,
Err(()) => {
if is_lenient {
debug_assert!(!JS_IsExceptionPending(cx));
*vp = UndefinedValue();
return true;
} else {
throw_invalid_this(cx, proto_id);
return if EXCEPTION_TO_REJECTION {
exception_to_promise(cx, args.rval())
} else {
false
};
}
},
};
call(
info,
cx,
obj.handle().into(),
this as *mut libc::c_void,
argc,
vp,
)
}
/// Generic method of IDL interface.
pub(crate) unsafe extern "C" fn generic_method<const EXCEPTION_TO_REJECTION: bool>(
cx: *mut JSContext,
argc: libc::c_uint,
vp: *mut JSVal,
) -> bool {
generic_call::<EXCEPTION_TO_REJECTION>(cx, argc, vp, false, CallJitMethodOp)
}
/// Generic getter of IDL interface.
pub(crate) unsafe extern "C" fn generic_getter<const EXCEPTION_TO_REJECTION: bool>(
cx: *mut JSContext,
argc: libc::c_uint,
vp: *mut JSVal,
) -> bool {
generic_call::<EXCEPTION_TO_REJECTION>(cx, argc, vp, false, CallJitGetterOp)
}
/// Generic lenient getter of IDL interface.
pub(crate) unsafe extern "C" fn generic_lenient_getter<const EXCEPTION_TO_REJECTION: bool>(
cx: *mut JSContext,
argc: libc::c_uint,
vp: *mut JSVal,
) -> bool {
generic_call::<EXCEPTION_TO_REJECTION>(cx, argc, vp, true, CallJitGetterOp)
}
unsafe extern "C" fn call_setter(
info: *const JSJitInfo,
cx: *mut JSContext,
handle: RawHandleObject,
this: *mut libc::c_void,
argc: u32,
vp: *mut JSVal,
) -> bool {
if !CallJitSetterOp(info, cx, handle, this, argc, vp) {
return false;
}
*vp = UndefinedValue();
true
}
/// Generic setter of IDL interface.
pub(crate) unsafe extern "C" fn generic_setter(
cx: *mut JSContext,
argc: libc::c_uint,
vp: *mut JSVal,
) -> bool {
generic_call::<false>(cx, argc, vp, false, call_setter)
}
/// Generic lenient setter of IDL interface.
pub(crate) unsafe extern "C" fn generic_lenient_setter(
cx: *mut JSContext,
argc: libc::c_uint,
vp: *mut JSVal,
) -> bool {
generic_call::<false>(cx, argc, vp, true, call_setter)
}
unsafe extern "C" fn instance_class_has_proto_at_depth(
clasp: *const js::jsapi::JSClass,
proto_id: u32,
depth: u32,
) -> bool {
let domclass: *const DOMJSClass = clasp as *const _;
let domclass = &*domclass;
domclass.dom_class.interface_chain[depth as usize] as u32 == proto_id
}
#[allow(missing_docs)] // FIXME
pub(crate) const DOM_CALLBACKS: DOMCallbacks = DOMCallbacks {
instanceClassMatchesProto: Some(instance_class_has_proto_at_depth),
};
// Generic method for returning libc::c_void from caller
pub(crate) trait AsVoidPtr {
fn as_void_ptr(&self) -> *const libc::c_void;
}
impl<T> AsVoidPtr for T {
fn as_void_ptr(&self) -> *const libc::c_void {
self as *const T as *const libc::c_void
}
}
// Generic method for returning c_char from caller
pub(crate) trait AsCCharPtrPtr {
fn as_c_char_ptr(&self) -> *const c_char;
}
impl AsCCharPtrPtr for [u8] {
fn as_c_char_ptr(&self) -> *const c_char {
self as *const [u8] as *const c_char
}
}
/// <https://searchfox.org/mozilla-central/rev/7279a1df13a819be254fd4649e07c4ff93e4bd45/dom/bindings/BindingUtils.cpp#3300>
pub(crate) unsafe extern "C" fn generic_static_promise_method(
cx: *mut JSContext,
argc: libc::c_uint,
vp: *mut JSVal,
) -> bool {
let args = CallArgs::from_vp(vp, argc);
let info = RUST_FUNCTION_VALUE_TO_JITINFO(JS_CALLEE(cx, vp));
assert!(!info.is_null());
// TODO: we need safe wrappers for this in mozjs!
//assert_eq!((*info)._bitfield_1, JSJitInfo_OpType::StaticMethod as u8)
let static_fn = (*info).__bindgen_anon_1.staticMethod.unwrap();
if static_fn(cx, argc, vp) {
return true;
}
exception_to_promise(cx, args.rval())
}
/// Coverts exception to promise rejection
///
/// <https://searchfox.org/mozilla-central/rev/b220e40ff2ee3d10ce68e07d8a8a577d5558e2a2/dom/bindings/BindingUtils.cpp#3315>
pub(crate) unsafe fn exception_to_promise(cx: *mut JSContext, rval: RawMutableHandleValue) -> bool {
rooted!(in(cx) let mut exception = UndefinedValue());
if !JS_GetPendingException(cx, exception.handle_mut()) {
return false;
}
JS_ClearPendingException(cx);
if let Some(promise) = NonNull::new(CallOriginalPromiseReject(cx, exception.handle())) {
promise.to_jsval(cx, MutableHandleValue::from_raw(rval));
true
} else {
// We just give up. Put the exception back.
JS_SetPendingException(cx, exception.handle(), ExceptionStackBehavior::Capture);
false
}
}