Adding upstream version 86.0.1.upstream/86.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1312 insertions, 0 deletions

diff --git a/js/rust/src/rust.rs b/js/rust/src/rust.rs
new file mode 100644
index 0000000000..c92554f91e
--- /dev/null
+++ b/js/rust/src/rust.rs
@@ -0,0 +1,1312 @@
+/* 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 http://mozilla.org/MPL/2.0/. */
+
+//! Rust wrappers around the raw JS apis
+
+use ar::AutoRealm;
+use glue::{
+    AppendToRootedObjectVector, CreateCallArgsFromVp, CreateRootedObjectVector,
+    DeleteRootedObjectVector, IsDebugBuild,
+};
+use glue::{
+    CreateRootedIdVector, DestroyRootedIdVector, GetMutableHandleIdVector, SliceRootedIdVector,
+};
+use glue::{DeleteCompileOptions, NewCompileOptions};
+use jsapi::root::*;
+use jsval::{self, UndefinedValue};
+use libc::c_uint;
+use panic;
+use std::cell::{Cell, UnsafeCell};
+use std::char;
+use std::default::Default;
+use std::ffi;
+use std::marker;
+use std::mem;
+use std::ops::{Deref, DerefMut};
+use std::ptr;
+use std::slice;
+use std::sync::atomic::{AtomicBool, AtomicPtr, AtomicUsize, Ordering};
+use std::sync::mpsc::{sync_channel, SyncSender};
+use std::sync::{Arc, Mutex, Once, ONCE_INIT};
+use std::thread;
+use std::u32;
+
+const DEFAULT_HEAPSIZE: u32 = 32_u32 * 1024_u32 * 1024_u32;
+
+// From Gecko:
+// Our "default" stack is what we use in configurations where we don't have a compelling reason to
+// do things differently. This is effectively 1MB on 64-bit platforms.
+const STACK_QUOTA: usize = 128 * 8 * 1024;
+
+// From Gecko:
+// (See js/xpconnect/src/XPCJSContext.cpp)
+// We tune the trusted/untrusted quotas for each configuration to achieve our
+// invariants while attempting to minimize overhead. In contrast, our buffer
+// between system code and trusted script is a very unscientific 10k.
+const SYSTEM_CODE_BUFFER: usize = 10 * 1024;
+
+// Gecko's value on 64-bit.
+const TRUSTED_SCRIPT_BUFFER: usize = 8 * 12800;
+
+trait ToResult {
+    fn to_result(self) -> Result<(), ()>;
+}
+
+impl ToResult for bool {
+    fn to_result(self) -> Result<(), ()> {
+        if self {
+            Ok(())
+        } else {
+            Err(())
+        }
+    }
+}
+
+// ___________________________________________________________________________
+// friendly Rustic API to runtimes
+
+thread_local!(static CONTEXT: Cell<*mut JSContext> = Cell::new(ptr::null_mut()));
+
+lazy_static! {
+    static ref OUTSTANDING_RUNTIMES: AtomicUsize = AtomicUsize::new(0);
+    static ref SHUT_DOWN: AtomicBool = AtomicBool::new(false);
+    static ref SHUT_DOWN_SIGNAL: Arc<Mutex<Option<SyncSender<()>>>> = Arc::new(Mutex::new(None));
+}
+
+/// A wrapper for the `JSContext` structure in SpiderMonkey.
+pub struct Runtime {
+    cx: *mut JSContext,
+}
+
+impl Runtime {
+    /// Get the `JSContext` for this thread.
+    pub fn get() -> *mut JSContext {
+        let cx = CONTEXT.with(|context| context.get());
+        assert!(!cx.is_null());
+        cx
+    }
+
+    /// Creates a new `JSContext`.
+    ///
+    /// * `use_internal_job_queue`: If `true`, then SpiderMonkey's internal
+    /// micro-task job queue is used. If `false`, then it is up to you to
+    /// implement micro-tasks yourself.
+    pub fn new(use_internal_job_queue: bool) -> Result<Runtime, ()> {
+        if SHUT_DOWN.load(Ordering::SeqCst) {
+            return Err(());
+        }
+
+        OUTSTANDING_RUNTIMES.fetch_add(1, Ordering::SeqCst);
+
+        unsafe {
+            #[derive(Debug)]
+            struct Parent(UnsafeCell<*mut JSContext>);
+            unsafe impl ::std::marker::Sync for Parent {}
+
+            impl Parent {
+                fn set(&self, val: *mut JSContext) {
+                    self.as_atomic().store(val, Ordering::SeqCst);
+                    assert_eq!(self.get(), val);
+                }
+
+                fn get(&self) -> *mut JSContext {
+                    self.as_atomic().load(Ordering::SeqCst)
+                }
+
+                fn as_atomic(&self) -> &AtomicPtr<JSContext> {
+                    unsafe { mem::transmute(&self.0) }
+                }
+            }
+
+            lazy_static! {
+                static ref PARENT: Parent = Parent(UnsafeCell::new(0 as *mut _));
+            }
+            static ONCE: Once = ONCE_INIT;
+
+            ONCE.call_once(|| {
+                // There is a 1:1 relationship between threads and JSContexts,
+                // so we must spawn a new thread for the parent context.
+                let (tx, rx) = sync_channel(0);
+                *SHUT_DOWN_SIGNAL.lock().unwrap() = Some(tx);
+                let _ = thread::spawn(move || {
+                    let is_debug_mozjs = cfg!(feature = "debugmozjs");
+                    let diagnostic = JS::detail::InitWithFailureDiagnostic(is_debug_mozjs);
+                    if !diagnostic.is_null() {
+                        panic!(
+                            "JS::detail::InitWithFailureDiagnostic failed: {}",
+                            ffi::CStr::from_ptr(diagnostic).to_string_lossy()
+                        );
+                    }
+
+                    let context = JS_NewContext(DEFAULT_HEAPSIZE, ptr::null_mut());
+                    assert!(!context.is_null());
+                    JS::InitSelfHostedCode(context);
+                    PARENT.set(context);
+
+                    // The last JSRuntime child died, resume the execution by destroying the parent.
+                    rx.recv().unwrap();
+                    let cx = PARENT.get();
+                    JS_DestroyContext(cx);
+                    JS_ShutDown();
+                    PARENT.set(0 as *mut _);
+                    // Unblock the last child thread, waiting for the JS_ShutDown.
+                    rx.recv().unwrap();
+                });
+
+                while PARENT.get().is_null() {
+                    thread::yield_now();
+                }
+            });
+
+            assert_eq!(IsDebugBuild(), cfg!(feature = "debugmozjs"));
+
+            let js_context = JS_NewContext(DEFAULT_HEAPSIZE, JS_GetParentRuntime(PARENT.get()));
+            assert!(!js_context.is_null());
+
+            // Unconstrain the runtime's threshold on nominal heap size, to avoid
+            // triggering GC too often if operating continuously near an arbitrary
+            // finite threshold. This leaves the maximum-JS_malloc-bytes threshold
+            // still in effect to cause periodical, and we hope hygienic,
+            // last-ditch GCs from within the GC's allocator.
+            JS_SetGCParameter(js_context, JSGCParamKey::JSGC_MAX_BYTES, u32::MAX);
+
+            JS_SetNativeStackQuota(
+                js_context,
+                STACK_QUOTA,
+                STACK_QUOTA - SYSTEM_CODE_BUFFER,
+                STACK_QUOTA - SYSTEM_CODE_BUFFER - TRUSTED_SCRIPT_BUFFER,
+            );
+
+            CONTEXT.with(|context| {
+                assert!(context.get().is_null());
+                context.set(js_context);
+            });
+
+            if use_internal_job_queue {
+                assert!(js::UseInternalJobQueues(js_context));
+            }
+
+            JS::InitSelfHostedCode(js_context);
+
+            JS::SetWarningReporter(js_context, Some(report_warning));
+
+            Ok(Runtime { cx: js_context })
+        }
+    }
+
+    /// Returns the underlying `JSContext` object.
+    pub fn cx(&self) -> *mut JSContext {
+        self.cx
+    }
+
+    /// Returns the underlying `JSContext`'s `JSRuntime`.
+    pub fn rt(&self) -> *mut JSRuntime {
+        unsafe { JS_GetRuntime(self.cx) }
+    }
+
+    pub fn evaluate_script(
+        &self,
+        glob: JS::HandleObject,
+        script: &str,
+        filename: &str,
+        line_num: u32,
+        rval: JS::MutableHandleValue,
+    ) -> Result<(), ()> {
+        let script_utf16: Vec<u16> = script.encode_utf16().collect();
+        let filename_cstr = ffi::CString::new(filename.as_bytes()).unwrap();
+        debug!(
+            "Evaluating script from {} with content {}",
+            filename, script
+        );
+        // SpiderMonkey does not approve of null pointers.
+        let (ptr, len) = if script_utf16.len() == 0 {
+            static empty: &'static [u16] = &[];
+            (empty.as_ptr(), 0)
+        } else {
+            (script_utf16.as_ptr(), script_utf16.len() as c_uint)
+        };
+        assert!(!ptr.is_null());
+        unsafe {
+            let _ar = AutoRealm::with_obj(self.cx(), glob.get());
+            let options = CompileOptionsWrapper::new(self.cx(), filename_cstr.as_ptr(), line_num);
+
+            let mut srcBuf = JS::SourceText {
+                units_: ptr,
+                length_: len as _,
+                ownsUnits_: false,
+                _phantom_0: marker::PhantomData,
+            };
+            if !JS::Evaluate(self.cx(), options.ptr, &mut srcBuf, rval) {
+                debug!("...err!");
+                panic::maybe_resume_unwind();
+                Err(())
+            } else {
+                // we could return the script result but then we'd have
+                // to root it and so forth and, really, who cares?
+                debug!("...ok!");
+                Ok(())
+            }
+        }
+    }
+}
+
+impl Drop for Runtime {
+    fn drop(&mut self) {
+        unsafe {
+            JS_DestroyContext(self.cx);
+
+            CONTEXT.with(|context| {
+                assert_eq!(context.get(), self.cx);
+                context.set(ptr::null_mut());
+            });
+
+            if OUTSTANDING_RUNTIMES.fetch_sub(1, Ordering::SeqCst) == 1 {
+                SHUT_DOWN.store(true, Ordering::SeqCst);
+                let signal = &SHUT_DOWN_SIGNAL.lock().unwrap();
+                let signal = signal.as_ref().unwrap();
+                // Send a signal to shutdown the Parent runtime.
+                signal.send(()).unwrap();
+                // Wait for it to be destroyed before resuming the execution
+                // of static variable destructors.
+                signal.send(()).unwrap();
+            }
+        }
+    }
+}
+
+// ___________________________________________________________________________
+// Rooting API for standard JS things
+
+pub trait RootKind {
+    #[inline(always)]
+    fn rootKind() -> JS::RootKind;
+}
+
+impl RootKind for *mut JSObject {
+    #[inline(always)]
+    fn rootKind() -> JS::RootKind {
+        JS::RootKind::Object
+    }
+}
+
+impl RootKind for *mut JSLinearString {
+    #[inline(always)]
+    fn rootKind() -> JS::RootKind {
+        JS::RootKind::String
+    }
+}
+
+impl RootKind for *mut JSFunction {
+    #[inline(always)]
+    fn rootKind() -> JS::RootKind {
+        JS::RootKind::Object
+    }
+}
+
+impl RootKind for *mut JSString {
+    #[inline(always)]
+    fn rootKind() -> JS::RootKind {
+        JS::RootKind::String
+    }
+}
+
+impl RootKind for *mut JS::Symbol {
+    #[inline(always)]
+    fn rootKind() -> JS::RootKind {
+        JS::RootKind::Symbol
+    }
+}
+
+#[cfg(feature = "bigint")]
+impl RootKind for *mut JS::BigInt {
+    #[inline(always)]
+    fn rootKind() -> JS::RootKind {
+        JS::RootKind::BigInt
+    }
+}
+
+impl RootKind for *mut JSScript {
+    #[inline(always)]
+    fn rootKind() -> JS::RootKind {
+        JS::RootKind::Script
+    }
+}
+
+impl RootKind for jsid {
+    #[inline(always)]
+    fn rootKind() -> JS::RootKind {
+        JS::RootKind::Id
+    }
+}
+
+impl RootKind for JS::Value {
+    #[inline(always)]
+    fn rootKind() -> JS::RootKind {
+        JS::RootKind::Value
+    }
+}
+
+impl<T> JS::Rooted<T> {
+    pub fn new_unrooted() -> JS::Rooted<T>
+    where
+        T: GCMethods,
+    {
+        JS::Rooted {
+            stack: ptr::null_mut(),
+            prev: ptr::null_mut(),
+            ptr: unsafe { T::initial() },
+            _phantom_0: marker::PhantomData,
+        }
+    }
+
+    unsafe fn get_rooting_context(cx: *mut JSContext) -> *mut JS::RootingContext {
+        mem::transmute(cx)
+    }
+
+    unsafe fn get_root_stack(
+        cx: *mut JSContext,
+    ) -> *mut *mut JS::Rooted<*mut JS::detail::RootListEntry>
+    where
+        T: RootKind,
+    {
+        let kind = T::rootKind() as usize;
+        let rooting_cx = Self::get_rooting_context(cx);
+        &mut rooting_cx.as_mut().unwrap().stackRoots_[kind] as *mut _ as *mut _
+    }
+
+    pub unsafe fn register_with_root_lists(&mut self, cx: *mut JSContext)
+    where
+        T: RootKind,
+    {
+        self.stack = Self::get_root_stack(cx);
+        let stack = self.stack.as_mut().unwrap();
+        self.prev = *stack as *mut _;
+
+        *stack = self as *mut _ as usize as _;
+    }
+
+    pub unsafe fn remove_from_root_stack(&mut self) {
+        assert!(*self.stack == self as *mut _ as usize as _);
+        *self.stack = self.prev;
+    }
+}
+
+/// Rust API for keeping a JS::Rooted value in the context's root stack.
+/// Example usage: `rooted!(in(cx) let x = UndefinedValue());`.
+/// `RootedGuard::new` also works, but the macro is preferred.
+pub struct RootedGuard<'a, T: 'a + RootKind + GCMethods> {
+    root: &'a mut JS::Rooted<T>,
+}
+
+impl<'a, T: 'a + RootKind + GCMethods> RootedGuard<'a, T> {
+    pub fn new(cx: *mut JSContext, root: &'a mut JS::Rooted<T>, initial: T) -> Self {
+        root.ptr = initial;
+        unsafe {
+            root.register_with_root_lists(cx);
+        }
+        RootedGuard { root: root }
+    }
+
+    pub fn handle(&self) -> JS::Handle<T> {
+        unsafe { JS::Handle::from_marked_location(&self.root.ptr) }
+    }
+
+    pub fn handle_mut(&mut self) -> JS::MutableHandle<T> {
+        unsafe { JS::MutableHandle::from_marked_location(&mut self.root.ptr) }
+    }
+
+    pub fn get(&self) -> T
+    where
+        T: Copy,
+    {
+        self.root.ptr
+    }
+
+    pub fn set(&mut self, v: T) {
+        self.root.ptr = v;
+    }
+}
+
+impl<'a, T: 'a + RootKind + GCMethods> Deref for RootedGuard<'a, T> {
+    type Target = T;
+    fn deref(&self) -> &T {
+        &self.root.ptr
+    }
+}
+
+impl<'a, T: 'a + RootKind + GCMethods> DerefMut for RootedGuard<'a, T> {
+    fn deref_mut(&mut self) -> &mut T {
+        &mut self.root.ptr
+    }
+}
+
+impl<'a, T: 'a + RootKind + GCMethods> Drop for RootedGuard<'a, T> {
+    fn drop(&mut self) {
+        unsafe {
+            self.root.ptr = T::initial();
+            self.root.remove_from_root_stack();
+        }
+    }
+}
+
+#[macro_export]
+macro_rules! rooted {
+    (in($cx:expr) let $name:ident = $init:expr) => {
+        let mut __root = $crate::jsapi::JS::Rooted::new_unrooted();
+        let $name = $crate::rust::RootedGuard::new($cx, &mut __root, $init);
+    };
+    (in($cx:expr) let mut $name:ident = $init:expr) => {
+        let mut __root = $crate::jsapi::JS::Rooted::new_unrooted();
+        let mut $name = $crate::rust::RootedGuard::new($cx, &mut __root, $init);
+    };
+}
+
+impl<T> JS::Handle<T> {
+    pub fn get(&self) -> T
+    where
+        T: Copy,
+    {
+        unsafe { *self.ptr }
+    }
+
+    pub unsafe fn from_marked_location(ptr: *const T) -> JS::Handle<T> {
+        JS::Handle {
+            ptr: mem::transmute(ptr),
+            _phantom_0: marker::PhantomData,
+        }
+    }
+}
+
+impl<T> Deref for JS::Handle<T> {
+    type Target = T;
+
+    fn deref<'a>(&'a self) -> &'a T {
+        unsafe { &*self.ptr }
+    }
+}
+
+impl<T> JS::MutableHandle<T> {
+    pub unsafe fn from_marked_location(ptr: *mut T) -> JS::MutableHandle<T> {
+        JS::MutableHandle {
+            ptr: ptr,
+            _phantom_0: marker::PhantomData,
+        }
+    }
+
+    pub fn handle(&self) -> JS::Handle<T> {
+        unsafe { JS::Handle::from_marked_location(self.ptr as *const _) }
+    }
+
+    pub fn get(&self) -> T
+    where
+        T: Copy,
+    {
+        unsafe { *self.ptr }
+    }
+
+    pub fn set(&self, v: T)
+    where
+        T: Copy,
+    {
+        unsafe { *self.ptr = v }
+    }
+}
+
+impl<T> Deref for JS::MutableHandle<T> {
+    type Target = T;
+
+    fn deref<'a>(&'a self) -> &'a T {
+        unsafe { &*self.ptr }
+    }
+}
+
+impl<T> DerefMut for JS::MutableHandle<T> {
+    fn deref_mut<'a>(&'a mut self) -> &'a mut T {
+        unsafe { &mut *self.ptr }
+    }
+}
+
+impl JS::HandleValue {
+    pub fn null() -> JS::HandleValue {
+        unsafe { JS::NullHandleValue }
+    }
+
+    pub fn undefined() -> JS::HandleValue {
+        unsafe { JS::UndefinedHandleValue }
+    }
+}
+
+impl JS::HandleValueArray {
+    pub fn new() -> JS::HandleValueArray {
+        JS::HandleValueArray {
+            length_: 0,
+            elements_: ptr::null(),
+        }
+    }
+
+    pub unsafe fn from_rooted_slice(values: &[JS::Value]) -> JS::HandleValueArray {
+        JS::HandleValueArray {
+            length_: values.len(),
+            elements_: values.as_ptr(),
+        }
+    }
+}
+
+const ConstNullValue: *mut JSObject = 0 as *mut JSObject;
+
+impl JS::HandleObject {
+    pub fn null() -> JS::HandleObject {
+        unsafe { JS::HandleObject::from_marked_location(&ConstNullValue) }
+    }
+}
+
+impl Default for jsid {
+    fn default() -> jsid {
+        jsid {
+            asBits: JSID_TYPE_VOID as usize,
+        }
+    }
+}
+
+impl Default for JS::Value {
+    fn default() -> JS::Value {
+        jsval::UndefinedValue()
+    }
+}
+
+impl Default for JS::RealmOptions {
+    fn default() -> Self {
+        unsafe { ::std::mem::zeroed() }
+    }
+}
+
+pub trait GCMethods {
+    unsafe fn initial() -> Self;
+    unsafe fn write_barriers(v: *mut Self, prev: Self, next: Self);
+}
+
+impl GCMethods for jsid {
+    unsafe fn initial() -> jsid {
+        Default::default()
+    }
+    unsafe fn write_barriers(_: *mut jsid, _: jsid, _: jsid) {}
+}
+
+#[cfg(feature = "bigint")]
+impl GCMethods for *mut JS::BigInt {
+    unsafe fn initial() -> *mut JS::BigInt {
+        ptr::null_mut()
+    }
+    unsafe fn write_barriers(
+        v: *mut *mut JS::BigInt,
+        prev: *mut JS::BigInt,
+        next: *mut JS::BigInt,
+    ) {
+        JS::HeapBigIntWriteBarriers(v, prev, next);
+    }
+}
+
+impl GCMethods for *mut JSObject {
+    unsafe fn initial() -> *mut JSObject {
+        ptr::null_mut()
+    }
+    unsafe fn write_barriers(v: *mut *mut JSObject, prev: *mut JSObject, next: *mut JSObject) {
+        JS::HeapObjectWriteBarriers(v, prev, next);
+    }
+}
+
+impl GCMethods for *mut JSString {
+    unsafe fn initial() -> *mut JSString {
+        ptr::null_mut()
+    }
+    unsafe fn write_barriers(v: *mut *mut JSString, prev: *mut JSString, next: *mut JSString) {
+        JS::HeapStringWriteBarriers(v, prev, next);
+    }
+}
+
+impl GCMethods for *mut JSScript {
+    unsafe fn initial() -> *mut JSScript {
+        ptr::null_mut()
+    }
+    unsafe fn write_barriers(v: *mut *mut JSScript, prev: *mut JSScript, next: *mut JSScript) {
+        JS::HeapScriptWriteBarriers(v, prev, next);
+    }
+}
+
+impl GCMethods for *mut JSFunction {
+    unsafe fn initial() -> *mut JSFunction {
+        ptr::null_mut()
+    }
+    unsafe fn write_barriers(
+        v: *mut *mut JSFunction,
+        prev: *mut JSFunction,
+        next: *mut JSFunction,
+    ) {
+        JS::HeapObjectWriteBarriers(
+            mem::transmute(v),
+            mem::transmute(prev),
+            mem::transmute(next),
+        );
+    }
+}
+
+impl GCMethods for JS::Value {
+    unsafe fn initial() -> JS::Value {
+        UndefinedValue()
+    }
+    unsafe fn write_barriers(v: *mut JS::Value, prev: JS::Value, next: JS::Value) {
+        JS::HeapValueWriteBarriers(v, &prev, &next);
+    }
+}
+
+// ___________________________________________________________________________
+// Implementations for various things in jsapi.rs
+
+impl Drop for JSAutoRealm {
+    fn drop(&mut self) {
+        unsafe {
+            JS::LeaveRealm(self.cx_, self.oldRealm_);
+        }
+    }
+}
+
+impl JSJitMethodCallArgs {
+    #[inline]
+    pub fn get(&self, i: u32) -> JS::HandleValue {
+        unsafe {
+            if i < self._base.argc_ {
+                JS::HandleValue::from_marked_location(self._base.argv_.offset(i as isize))
+            } else {
+                JS::UndefinedHandleValue
+            }
+        }
+    }
+
+    #[inline]
+    pub fn index(&self, i: u32) -> JS::HandleValue {
+        assert!(i < self._base.argc_);
+        unsafe { JS::HandleValue::from_marked_location(self._base.argv_.offset(i as isize)) }
+    }
+
+    #[inline]
+    pub fn index_mut(&self, i: u32) -> JS::MutableHandleValue {
+        assert!(i < self._base.argc_);
+        unsafe { JS::MutableHandleValue::from_marked_location(self._base.argv_.offset(i as isize)) }
+    }
+
+    #[inline]
+    pub fn rval(&self) -> JS::MutableHandleValue {
+        unsafe { JS::MutableHandleValue::from_marked_location(self._base.argv_.offset(-2)) }
+    }
+}
+
+// XXX need to hack up bindgen to convert this better so we don't have
+//     to duplicate so much code here
+impl JS::CallArgs {
+    #[inline]
+    pub unsafe fn from_vp(vp: *mut JS::Value, argc: u32) -> JS::CallArgs {
+        CreateCallArgsFromVp(argc, vp)
+    }
+
+    #[inline]
+    pub fn index(&self, i: u32) -> JS::HandleValue {
+        assert!(i < self._base.argc_);
+        unsafe { JS::HandleValue::from_marked_location(self._base.argv_.offset(i as isize)) }
+    }
+
+    #[inline]
+    pub fn index_mut(&self, i: u32) -> JS::MutableHandleValue {
+        assert!(i < self._base.argc_);
+        unsafe { JS::MutableHandleValue::from_marked_location(self._base.argv_.offset(i as isize)) }
+    }
+
+    #[inline]
+    pub fn get(&self, i: u32) -> JS::HandleValue {
+        unsafe {
+            if i < self._base.argc_ {
+                JS::HandleValue::from_marked_location(self._base.argv_.offset(i as isize))
+            } else {
+                JS::UndefinedHandleValue
+            }
+        }
+    }
+
+    #[inline]
+    pub fn rval(&self) -> JS::MutableHandleValue {
+        unsafe { JS::MutableHandleValue::from_marked_location(self._base.argv_.offset(-2)) }
+    }
+
+    #[inline]
+    pub fn thisv(&self) -> JS::HandleValue {
+        unsafe { JS::HandleValue::from_marked_location(self._base.argv_.offset(-1)) }
+    }
+
+    #[inline]
+    pub fn calleev(&self) -> JS::HandleValue {
+        unsafe { JS::HandleValue::from_marked_location(self._base.argv_.offset(-2)) }
+    }
+
+    #[inline]
+    pub fn callee(&self) -> *mut JSObject {
+        self.calleev().to_object()
+    }
+
+    #[inline]
+    pub fn new_target(&self) -> JS::MutableHandleValue {
+        assert!(self._base.constructing_());
+        unsafe {
+            JS::MutableHandleValue::from_marked_location(
+                self._base.argv_.offset(self._base.argc_ as isize),
+            )
+        }
+    }
+}
+
+impl JSJitGetterCallArgs {
+    #[inline]
+    pub fn rval(&self) -> JS::MutableHandleValue {
+        self._base
+    }
+}
+
+impl JSJitSetterCallArgs {
+    #[inline]
+    pub fn get(&self, i: u32) -> JS::HandleValue {
+        assert!(i == 0);
+        self._base.handle()
+    }
+}
+
+// ___________________________________________________________________________
+// Wrappers around things in jsglue.cpp
+
+pub struct RootedObjectVectorWrapper {
+    pub ptr: *mut JS::PersistentRootedObjectVector,
+}
+
+impl RootedObjectVectorWrapper {
+    pub fn new(cx: *mut JSContext) -> RootedObjectVectorWrapper {
+        RootedObjectVectorWrapper {
+            ptr: unsafe { CreateRootedObjectVector(cx) },
+        }
+    }
+
+    pub fn append(&self, obj: *mut JSObject) -> bool {
+        unsafe { AppendToRootedObjectVector(self.ptr, obj) }
+    }
+}
+
+impl Drop for RootedObjectVectorWrapper {
+    fn drop(&mut self) {
+        unsafe { DeleteRootedObjectVector(self.ptr) }
+    }
+}
+
+pub struct CompileOptionsWrapper {
+    pub ptr: *mut JS::ReadOnlyCompileOptions,
+}
+
+impl CompileOptionsWrapper {
+    pub fn new(
+        cx: *mut JSContext,
+        file: *const ::libc::c_char,
+        line: c_uint,
+    ) -> CompileOptionsWrapper {
+        CompileOptionsWrapper {
+            ptr: unsafe { NewCompileOptions(cx, file, line) },
+        }
+    }
+}
+
+impl Drop for CompileOptionsWrapper {
+    fn drop(&mut self) {
+        unsafe { DeleteCompileOptions(self.ptr) }
+    }
+}
+
+// ___________________________________________________________________________
+// Fast inline converters
+
+#[inline]
+pub unsafe fn ToBoolean(v: JS::HandleValue) -> bool {
+    let val = *v.ptr;
+
+    if val.is_boolean() {
+        return val.to_boolean();
+    }
+
+    if val.is_int32() {
+        return val.to_int32() != 0;
+    }
+
+    if val.is_null_or_undefined() {
+        return false;
+    }
+
+    if val.is_double() {
+        let d = val.to_double();
+        return !d.is_nan() && d != 0f64;
+    }
+
+    if val.is_symbol() {
+        return true;
+    }
+
+    js::ToBooleanSlow(v)
+}
+
+#[inline]
+pub unsafe fn ToNumber(cx: *mut JSContext, v: JS::HandleValue) -> Result<f64, ()> {
+    let val = *v.ptr;
+    if val.is_number() {
+        return Ok(val.to_number());
+    }
+
+    let mut out = Default::default();
+    if js::ToNumberSlow(cx, v, &mut out) {
+        Ok(out)
+    } else {
+        Err(())
+    }
+}
+
+#[inline]
+unsafe fn convert_from_int32<T: Default + Copy>(
+    cx: *mut JSContext,
+    v: JS::HandleValue,
+    conv_fn: unsafe extern "C" fn(*mut JSContext, JS::HandleValue, *mut T) -> bool,
+) -> Result<T, ()> {
+    let val = *v.ptr;
+    if val.is_int32() {
+        let intval: i64 = val.to_int32() as i64;
+        // TODO: do something better here that works on big endian
+        let intval = *(&intval as *const i64 as *const T);
+        return Ok(intval);
+    }
+
+    let mut out = Default::default();
+    if conv_fn(cx, v, &mut out) {
+        Ok(out)
+    } else {
+        Err(())
+    }
+}
+
+#[inline]
+pub unsafe fn ToInt32(cx: *mut JSContext, v: JS::HandleValue) -> Result<i32, ()> {
+    convert_from_int32::<i32>(cx, v, js::ToInt32Slow)
+}
+
+#[inline]
+pub unsafe fn ToUint32(cx: *mut JSContext, v: JS::HandleValue) -> Result<u32, ()> {
+    convert_from_int32::<u32>(cx, v, js::ToUint32Slow)
+}
+
+#[inline]
+pub unsafe fn ToUint16(cx: *mut JSContext, v: JS::HandleValue) -> Result<u16, ()> {
+    convert_from_int32::<u16>(cx, v, js::ToUint16Slow)
+}
+
+#[inline]
+pub unsafe fn ToInt64(cx: *mut JSContext, v: JS::HandleValue) -> Result<i64, ()> {
+    convert_from_int32::<i64>(cx, v, js::ToInt64Slow)
+}
+
+#[inline]
+pub unsafe fn ToUint64(cx: *mut JSContext, v: JS::HandleValue) -> Result<u64, ()> {
+    convert_from_int32::<u64>(cx, v, js::ToUint64Slow)
+}
+
+#[inline]
+pub unsafe fn ToString(cx: *mut JSContext, v: JS::HandleValue) -> *mut JSString {
+    let val = *v.ptr;
+    if val.is_string() {
+        return val.to_string();
+    }
+
+    js::ToStringSlow(cx, v)
+}
+
+pub unsafe extern "C" fn report_warning(_cx: *mut JSContext, report: *mut JSErrorReport) {
+    fn latin1_to_string(bytes: &[u8]) -> String {
+        bytes
+            .iter()
+            .map(|c| char::from_u32(*c as u32).unwrap())
+            .collect()
+    }
+
+    let fnptr = (*report)._base.filename;
+    let fname = if !fnptr.is_null() {
+        let c_str = ffi::CStr::from_ptr(fnptr);
+        latin1_to_string(c_str.to_bytes())
+    } else {
+        "none".to_string()
+    };
+
+    let lineno = (*report)._base.lineno;
+    let column = (*report)._base.column;
+
+    let msg_ptr = (*report)._base.message_.data_ as *const u16;
+    let msg_len = (0usize..)
+        .find(|&i| *msg_ptr.offset(i as isize) == 0)
+        .unwrap();
+    let msg_slice = slice::from_raw_parts(msg_ptr, msg_len);
+    let msg = String::from_utf16_lossy(msg_slice);
+
+    warn!("Warning at {}:{}:{}: {}\n", fname, lineno, column, msg);
+}
+
+impl JSNativeWrapper {
+    fn is_zeroed(&self) -> bool {
+        let JSNativeWrapper { op, info } = *self;
+        op.is_none() && info.is_null()
+    }
+}
+
+pub struct RootedIdVectorWrapper {
+    pub ptr: *mut JS::PersistentRootedIdVector,
+}
+
+impl RootedIdVectorWrapper {
+    pub fn new(cx: *mut JSContext) -> RootedIdVectorWrapper {
+        RootedIdVectorWrapper {
+            ptr: unsafe { CreateRootedIdVector(cx) },
+        }
+    }
+
+    pub fn handle_mut(&self) -> JS::MutableHandleIdVector {
+        unsafe { GetMutableHandleIdVector(self.ptr) }
+    }
+}
+
+impl Drop for RootedIdVectorWrapper {
+    fn drop(&mut self) {
+        unsafe { DestroyRootedIdVector(self.ptr) }
+    }
+}
+
+impl Deref for RootedIdVectorWrapper {
+    type Target = [jsid];
+
+    fn deref(&self) -> &[jsid] {
+        unsafe {
+            let mut length = 0;
+            let pointer = SliceRootedIdVector(self.ptr as *const _, &mut length);
+            slice::from_raw_parts(pointer, length)
+        }
+    }
+}
+
+/// Defines methods on `obj`. The last entry of `methods` must contain zeroed
+/// memory.
+///
+/// # Failures
+///
+/// Returns `Err` on JSAPI failure.
+///
+/// # Panics
+///
+/// Panics if the last entry of `methods` does not contain zeroed memory.
+///
+/// # Safety
+///
+/// - `cx` must be valid.
+/// - This function calls into unaudited C++ code.
+pub unsafe fn define_methods(
+    cx: *mut JSContext,
+    obj: JS::HandleObject,
+    methods: &'static [JSFunctionSpec],
+) -> Result<(), ()> {
+    assert!({
+        match methods.last() {
+            Some(&JSFunctionSpec {
+                name: JSFunctionSpec_Name { string_: name },
+                call,
+                nargs,
+                flags,
+                selfHostedName,
+            }) => {
+                name.is_null()
+                    && call.is_zeroed()
+                    && nargs == 0
+                    && flags == 0
+                    && selfHostedName.is_null()
+            }
+            None => false,
+        }
+    });
+
+    JS_DefineFunctions(cx, obj, methods.as_ptr()).to_result()
+}
+
+/// Defines attributes on `obj`. The last entry of `properties` must contain
+/// zeroed memory.
+///
+/// # Failures
+///
+/// Returns `Err` on JSAPI failure.
+///
+/// # Panics
+///
+/// Panics if the last entry of `properties` does not contain zeroed memory.
+///
+/// # Safety
+///
+/// - `cx` must be valid.
+/// - This function calls into unaudited C++ code.
+pub unsafe fn define_properties(
+    cx: *mut JSContext,
+    obj: JS::HandleObject,
+    properties: &'static [JSPropertySpec],
+) -> Result<(), ()> {
+    assert!(!properties.is_empty());
+    assert!({
+        let spec = properties.last().unwrap();
+        let slice = slice::from_raw_parts(
+            spec as *const _ as *const u8,
+            mem::size_of::<JSPropertySpec>(),
+        );
+        slice.iter().all(|byte| *byte == 0)
+    });
+
+    JS_DefineProperties(cx, obj, properties.as_ptr()).to_result()
+}
+
+static SIMPLE_GLOBAL_CLASS_OPS: JSClassOps = JSClassOps {
+    addProperty: None,
+    delProperty: None,
+    enumerate: Some(JS_EnumerateStandardClasses),
+    newEnumerate: None,
+    resolve: Some(JS_ResolveStandardClass),
+    mayResolve: Some(JS_MayResolveStandardClass),
+    finalize: None,
+    call: None,
+    hasInstance: None,
+    construct: None,
+    trace: Some(JS_GlobalObjectTraceHook),
+};
+
+/// This is a simple `JSClass` for global objects, primarily intended for tests.
+pub static SIMPLE_GLOBAL_CLASS: JSClass = JSClass {
+    name: b"Global\0" as *const u8 as *const _,
+    flags: (JSCLASS_IS_GLOBAL
+        | ((JSCLASS_GLOBAL_SLOT_COUNT & JSCLASS_RESERVED_SLOTS_MASK)
+            << JSCLASS_RESERVED_SLOTS_SHIFT)) as u32,
+    cOps: &SIMPLE_GLOBAL_CLASS_OPS as *const JSClassOps,
+    spec: 0 as *mut _,
+    ext: 0 as *mut _,
+    oOps: 0 as *mut _,
+};
+
+#[inline]
+unsafe fn get_object_group(obj: *mut JSObject) -> *mut JS::shadow::ObjectGroup {
+    assert!(!obj.is_null());
+    let obj = obj as *mut JS::shadow::Object;
+    (*obj).group
+}
+
+#[inline]
+pub unsafe fn get_object_class(obj: *mut JSObject) -> *const JSClass {
+    (*get_object_group(obj)).clasp as *const _
+}
+
+#[inline]
+pub unsafe fn get_object_compartment(obj: *mut JSObject) -> *mut JS::Compartment {
+    let realm = (*get_object_group(obj)).realm as *const JS::shadow::Realm;
+    (*realm).compartment_
+}
+
+#[inline]
+pub fn is_dom_class(class: &JSClass) -> bool {
+    class.flags & JSCLASS_IS_DOMJSCLASS != 0
+}
+
+#[inline]
+pub unsafe fn is_dom_object(obj: *mut JSObject) -> bool {
+    is_dom_class(&*get_object_class(obj))
+}
+
+#[inline]
+pub unsafe fn is_global(obj: *mut JSObject) -> bool {
+    (*get_object_class(obj)).flags & JSCLASS_IS_GLOBAL != 0
+}
+
+#[inline]
+pub unsafe fn is_window(obj: *mut JSObject) -> bool {
+    is_global(obj) && js::detail::IsWindowSlow(obj)
+}
+
+#[inline]
+pub unsafe fn try_to_outerize(rval: JS::MutableHandleValue) {
+    let obj = rval.to_object();
+    if is_window(obj) {
+        let obj = js::detail::ToWindowProxyIfWindowSlow(obj);
+        assert!(!obj.is_null());
+        rval.set(jsval::ObjectValue(&mut *obj));
+    }
+}
+
+#[inline]
+pub unsafe fn maybe_wrap_object_value(cx: *mut JSContext, rval: JS::MutableHandleValue) {
+    assert!(rval.is_object());
+
+    // There used to be inline checks if this out of line call was necessary or
+    // not here, but JSAPI no longer exposes a way to get a JSContext's
+    // compartment, and additionally JSContext is under a bunch of churn in
+    // JSAPI in general right now.
+
+    assert!(JS_WrapValue(cx, rval));
+}
+
+#[inline]
+pub unsafe fn maybe_wrap_object_or_null_value(cx: *mut JSContext, rval: JS::MutableHandleValue) {
+    assert!(rval.is_object_or_null());
+    if !rval.is_null() {
+        maybe_wrap_object_value(cx, rval);
+    }
+}
+
+#[inline]
+pub unsafe fn maybe_wrap_value(cx: *mut JSContext, rval: JS::MutableHandleValue) {
+    if rval.is_string() {
+        assert!(JS_WrapValue(cx, rval));
+    } else if rval.is_object() {
+        maybe_wrap_object_value(cx, rval);
+    }
+}
+
+/// Equivalents of the JS_FN* macros.
+impl JSFunctionSpec {
+    pub fn js_fs(
+        name: *const ::std::os::raw::c_char,
+        func: JSNative,
+        nargs: u16,
+        flags: u16,
+    ) -> JSFunctionSpec {
+        JSFunctionSpec {
+            name: JSFunctionSpec_Name { string_: name },
+            call: JSNativeWrapper {
+                op: func,
+                info: ptr::null(),
+            },
+            nargs: nargs,
+            flags: flags,
+            selfHostedName: 0 as *const _,
+        }
+    }
+
+    pub fn js_fn(
+        name: *const ::std::os::raw::c_char,
+        func: JSNative,
+        nargs: u16,
+        flags: u16,
+    ) -> JSFunctionSpec {
+        JSFunctionSpec {
+            name: JSFunctionSpec_Name { string_: name },
+            call: JSNativeWrapper {
+                op: func,
+                info: ptr::null(),
+            },
+            nargs: nargs,
+            flags: flags,
+            selfHostedName: 0 as *const _,
+        }
+    }
+
+    pub const NULL: JSFunctionSpec = JSFunctionSpec {
+        name: JSFunctionSpec_Name {
+            string_: 0 as *const _,
+        },
+        call: JSNativeWrapper {
+            op: None,
+            info: 0 as *const _,
+        },
+        nargs: 0,
+        flags: 0,
+        selfHostedName: 0 as *const _,
+    };
+}
+
+/// Equivalents of the JS_PS* macros.
+impl JSPropertySpec {
+    pub fn getter(
+        name: *const ::std::os::raw::c_char,
+        flags: u8,
+        func: JSNative,
+    ) -> JSPropertySpec {
+        debug_assert_eq!(flags & !(JSPROP_ENUMERATE | JSPROP_PERMANENT), 0);
+        JSPropertySpec {
+            name: JSPropertySpec_Name { string_: name },
+            flags_: flags,
+            u: JSPropertySpec_AccessorsOrValue {
+                accessors: JSPropertySpec_AccessorsOrValue_Accessors {
+                    getter: JSPropertySpec_Accessor {
+                        native: JSNativeWrapper {
+                            op: func,
+                            info: ptr::null(),
+                        },
+                    },
+                    setter: JSPropertySpec_Accessor {
+                        native: JSNativeWrapper {
+                            op: None,
+                            info: ptr::null(),
+                        },
+                    },
+                },
+            },
+        }
+    }
+
+    pub fn getter_setter(
+        name: *const ::std::os::raw::c_char,
+        flags: u8,
+        g_f: JSNative,
+        s_f: JSNative,
+    ) -> JSPropertySpec {
+        debug_assert_eq!(flags & !(JSPROP_ENUMERATE | JSPROP_PERMANENT), 0);
+        JSPropertySpec {
+            name: JSPropertySpec_Name { string_: name },
+            flags_: flags,
+            u: JSPropertySpec_AccessorsOrValue {
+                accessors: JSPropertySpec_AccessorsOrValue_Accessors {
+                    getter: JSPropertySpec_Accessor {
+                        native: JSNativeWrapper {
+                            op: g_f,
+                            info: ptr::null(),
+                        },
+                    },
+                    setter: JSPropertySpec_Accessor {
+                        native: JSNativeWrapper {
+                            op: s_f,
+                            info: ptr::null(),
+                        },
+                    },
+                },
+            },
+        }
+    }
+
+    pub const NULL: JSPropertySpec = JSPropertySpec {
+        name: JSPropertySpec_Name {
+            string_: 0 as *const _,
+        },
+        flags_: 0,
+        u: JSPropertySpec_AccessorsOrValue {
+            accessors: JSPropertySpec_AccessorsOrValue_Accessors {
+                getter: JSPropertySpec_Accessor {
+                    native: JSNativeWrapper {
+                        op: None,
+                        info: 0 as *const _,
+                    },
+                },
+                setter: JSPropertySpec_Accessor {
+                    native: JSNativeWrapper {
+                        op: None,
+                        info: 0 as *const _,
+                    },
+                },
+            },
+        },
+    };
+}