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use std::borrow::Borrow;
use std::hash::Hash;
use std::hash::Hasher;
use std::marker::PhantomData;
use std::mem::transmute;
use std::ops::Deref;
use std::ptr::NonNull;
use crate::Data;
use crate::HandleScope;
use crate::Isolate;
use crate::IsolateHandle;
extern "C" {
fn v8__Local__New(isolate: *mut Isolate, other: *const Data) -> *const Data;
fn v8__Global__New(isolate: *mut Isolate, data: *const Data) -> *const Data;
fn v8__Global__Reset(data: *const Data);
}
#[repr(C)]
#[derive(Debug)]
pub struct Local<'s, T>(NonNull<T>, PhantomData<&'s ()>);
impl<'s, T> Local<'s, T> {
pub fn new(
scope: &mut HandleScope<'s, ()>,
handle: impl Handle<Data = T>,
) -> Self {
let HandleInfo { data, host } = handle.get_handle_info();
host.assert_match_isolate(scope);
unsafe {
scope.cast_local(|sd| {
v8__Local__New(sd.get_isolate_ptr(), data.cast().as_ptr()) as *const T
})
}
.unwrap()
}
pub unsafe fn cast<A>(other: Local<'s, A>) -> Self
where
Local<'s, A>: From<Self>,
{
transmute(other)
}
pub(crate) unsafe fn from_raw(ptr: *const T) -> Option<Self> {
NonNull::new(ptr as *mut _).map(|nn| Self::from_non_null(nn))
}
pub(crate) unsafe fn from_non_null(nn: NonNull<T>) -> Self {
Self(nn, PhantomData)
}
pub(crate) fn as_non_null(self) -> NonNull<T> {
self.0
}
pub(crate) fn slice_into_raw(slice: &[Self]) -> &[*const T] {
unsafe { &*(slice as *const [Self] as *const [*const T]) }
}
}
impl<'s, T> Copy for Local<'s, T> {}
impl<'s, T> Clone for Local<'s, T> {
fn clone(&self) -> Self {
*self
}
}
impl<'s, T> Deref for Local<'s, T> {
type Target = T;
fn deref(&self) -> &T {
unsafe { self.0.as_ref() }
}
}
#[derive(Debug)]
pub struct Global<T> {
data: NonNull<T>,
isolate_handle: IsolateHandle,
}
impl<T> Global<T> {
pub fn new(isolate: &mut Isolate, handle: impl Handle<Data = T>) -> Self {
let HandleInfo { data, host } = handle.get_handle_info();
host.assert_match_isolate(isolate);
unsafe { Self::new_raw(isolate, data) }
}
unsafe fn new_raw(isolate: *mut Isolate, data: NonNull<T>) -> Self {
let data = data.cast().as_ptr();
let data = v8__Global__New(isolate, data) as *const T;
let data = NonNull::new_unchecked(data as *mut _);
let isolate_handle = (*isolate).thread_safe_handle();
Self {
data,
isolate_handle,
}
}
pub fn get<'a>(&'a self, scope: &mut Isolate) -> &'a T {
Handle::get(self, scope)
}
}
impl<T> Clone for Global<T> {
fn clone(&self) -> Self {
let HandleInfo { data, host } = self.get_handle_info();
unsafe { Self::new_raw(host.get_isolate().as_mut(), data) }
}
}
impl<T> Drop for Global<T> {
fn drop(&mut self) {
unsafe {
if self.isolate_handle.get_isolate_ptr().is_null() {
} else {
v8__Global__Reset(self.data.cast().as_ptr())
}
}
}
}
pub trait Handle: Sized {
type Data;
#[doc(hidden)]
fn get_handle_info(&self) -> HandleInfo<Self::Data>;
fn get<'a>(&'a self, isolate: &mut Isolate) -> &'a Self::Data {
let HandleInfo { data, host } = self.get_handle_info();
host.assert_match_isolate(isolate);
unsafe { &*data.as_ptr() }
}
unsafe fn get_unchecked(&self) -> &Self::Data {
let HandleInfo { data, host } = self.get_handle_info();
if let HandleHost::DisposedIsolate = host {
panic!("attempt to access Handle hosted by disposed Isolate");
}
&*data.as_ptr()
}
}
impl<'s, T> Handle for Local<'s, T> {
type Data = T;
fn get_handle_info(&self) -> HandleInfo<T> {
HandleInfo::new(self.as_non_null(), HandleHost::Scope)
}
}
impl<'a, 's: 'a, T> Handle for &'a Local<'s, T> {
type Data = T;
fn get_handle_info(&self) -> HandleInfo<T> {
HandleInfo::new(self.as_non_null(), HandleHost::Scope)
}
}
impl<T> Handle for Global<T> {
type Data = T;
fn get_handle_info(&self) -> HandleInfo<T> {
HandleInfo::new(self.data, (&self.isolate_handle).into())
}
}
impl<'a, T> Handle for &'a Global<T> {
type Data = T;
fn get_handle_info(&self) -> HandleInfo<T> {
HandleInfo::new(self.data, (&self.isolate_handle).into())
}
}
impl<'s, T> Borrow<T> for Local<'s, T> {
fn borrow(&self) -> &T {
&**self
}
}
impl<T> Borrow<T> for Global<T> {
fn borrow(&self) -> &T {
let HandleInfo { data, host } = self.get_handle_info();
if let HandleHost::DisposedIsolate = host {
panic!("attempt to access Handle hosted by disposed Isolate");
}
unsafe { &*data.as_ptr() }
}
}
impl<'s, T> Eq for Local<'s, T> where T: Eq {}
impl<T> Eq for Global<T> where T: Eq {}
impl<'s, T: Hash> Hash for Local<'s, T> {
fn hash<H: Hasher>(&self, state: &mut H) {
(&**self).hash(state)
}
}
impl<T: Hash> Hash for Global<T> {
fn hash<H: Hasher>(&self, state: &mut H) {
unsafe {
if self.isolate_handle.get_isolate_ptr().is_null() {
panic!("can't hash Global after its host Isolate has been disposed");
}
self.data.as_ref().hash(state);
}
}
}
impl<'s, T, Rhs: Handle> PartialEq<Rhs> for Local<'s, T>
where
T: PartialEq<Rhs::Data>,
{
fn eq(&self, other: &Rhs) -> bool {
let i1 = self.get_handle_info();
let i2 = other.get_handle_info();
i1.host.match_host(i2.host, None)
&& unsafe { i1.data.as_ref() == i2.data.as_ref() }
}
}
impl<'s, T, Rhs: Handle> PartialEq<Rhs> for Global<T>
where
T: PartialEq<Rhs::Data>,
{
fn eq(&self, other: &Rhs) -> bool {
let i1 = self.get_handle_info();
let i2 = other.get_handle_info();
i1.host.match_host(i2.host, None)
&& unsafe { i1.data.as_ref() == i2.data.as_ref() }
}
}
#[derive(Copy, Debug, Clone)]
pub struct HandleInfo<T> {
data: NonNull<T>,
host: HandleHost,
}
impl<T> HandleInfo<T> {
fn new(data: NonNull<T>, host: HandleHost) -> Self {
Self { data, host }
}
}
#[derive(Copy, Debug, Clone)]
enum HandleHost {
Scope,
Isolate(NonNull<Isolate>),
DisposedIsolate,
}
impl From<&'_ mut Isolate> for HandleHost {
fn from(isolate: &'_ mut Isolate) -> Self {
Self::Isolate(NonNull::from(isolate))
}
}
impl From<&'_ IsolateHandle> for HandleHost {
fn from(isolate_handle: &IsolateHandle) -> Self {
NonNull::new(unsafe { isolate_handle.get_isolate_ptr() })
.map(Self::Isolate)
.unwrap_or(Self::DisposedIsolate)
}
}
impl HandleHost {
fn match_host(
self,
other: Self,
scope_isolate_opt: Option<&mut Isolate>,
) -> bool {
let scope_isolate_opt_nn = scope_isolate_opt.map(NonNull::from);
match (self, other, scope_isolate_opt_nn) {
(Self::Scope, Self::Scope, _) => true,
(Self::Isolate(ile1), Self::Isolate(ile2), _) => ile1 == ile2,
(Self::Scope, Self::Isolate(ile1), Some(ile2)) => ile1 == ile2,
(Self::Isolate(ile1), Self::Scope, Some(ile2)) => ile1 == ile2,
(Self::Scope, Self::Isolate(_), _) => true,
(Self::Isolate(_), Self::Scope, _) => true,
(Self::DisposedIsolate, ..) | (_, Self::DisposedIsolate, _) => {
panic!("attempt to access Handle hosted by disposed Isolate")
}
}
}
fn assert_match_host(self, other: Self, scope_opt: Option<&mut Isolate>) {
assert!(
self.match_host(other, scope_opt),
"attempt to use Handle in an Isolate that is not its host"
)
}
fn match_isolate(self, isolate: &mut Isolate) -> bool {
self.match_host(isolate.into(), Some(isolate))
}
fn assert_match_isolate(self, isolate: &mut Isolate) {
self.assert_match_host(isolate.into(), Some(isolate))
}
fn get_isolate(self) -> NonNull<Isolate> {
match self {
Self::Scope => panic!("host Isolate for Handle not available"),
Self::Isolate(ile) => ile,
Self::DisposedIsolate => panic!("attempt to access disposed Isolate"),
}
}
fn get_isolate_handle(self) -> IsolateHandle {
unsafe { self.get_isolate().as_ref() }.thread_safe_handle()
}
}