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rust.rs
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/* 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 std::cell::Cell;
use std::char;
use std::default::Default;
use std::ffi;
use std::ffi::CStr;
use std::marker::PhantomData;
use std::mem::MaybeUninit;
use std::ops::{Deref, DerefMut};
use std::ptr::{self, NonNull};
use std::slice;
use std::str;
use std::sync::atomic::{AtomicU32, Ordering};
use std::sync::{Arc, Mutex, RwLock};
use crate::consts::{JSCLASS_GLOBAL_SLOT_COUNT, JSCLASS_RESERVED_SLOTS_MASK};
use crate::consts::{JSCLASS_IS_DOMJSCLASS, JSCLASS_IS_GLOBAL};
use crate::conversions::jsstr_to_string;
use crate::default_heapsize;
pub use crate::gc::*;
use crate::glue::AppendToRootedObjectVector;
use crate::glue::{CreateRootedIdVector, CreateRootedObjectVector};
use crate::glue::{
DeleteCompileOptions, DeleteRootedObjectVector, DescribeScriptedCaller, DestroyRootedIdVector,
};
use crate::glue::{
GetIdVectorAddress, GetObjectVectorAddress, NewCompileOptions, SliceRootedIdVector,
};
use crate::jsapi;
use crate::jsapi::glue::{DeleteRealmOptions, JS_Init, JS_NewRealmOptions};
use crate::jsapi::js::frontend::CompilationStencil;
use crate::jsapi::mozilla::Utf8Unit;
use crate::jsapi::shadow::BaseShape;
use crate::jsapi::HandleObjectVector as RawHandleObjectVector;
use crate::jsapi::HandleValue as RawHandleValue;
use crate::jsapi::JS_AddExtraGCRootsTracer;
use crate::jsapi::MutableHandleIdVector as RawMutableHandleIdVector;
use crate::jsapi::{already_AddRefed, jsid};
use crate::jsapi::{BuildStackString, CaptureCurrentStack, StackFormat};
use crate::jsapi::{Evaluate2, HandleValueArray, StencilRelease};
use crate::jsapi::{InitSelfHostedCode, IsWindowSlow};
use crate::jsapi::{
JSAutoRealm, JS_SetGCParameter, JS_SetNativeStackQuota, JS_WrapObject, JS_WrapValue,
};
use crate::jsapi::{JSClass, JSClassOps, JSContext, Realm, JSCLASS_RESERVED_SLOTS_SHIFT};
use crate::jsapi::{JSErrorReport, JSFunctionSpec, JSGCParamKey};
use crate::jsapi::{JSObject, JSPropertySpec, JSRuntime};
use crate::jsapi::{JSString, Object, PersistentRootedIdVector};
use crate::jsapi::{JS_DefineFunctions, JS_DefineProperties, JS_DestroyContext, JS_ShutDown};
use crate::jsapi::{JS_EnumerateStandardClasses, JS_GetRuntime, JS_GlobalObjectTraceHook};
use crate::jsapi::{JS_MayResolveStandardClass, JS_NewContext, JS_ResolveStandardClass};
use crate::jsapi::{JS_RequestInterruptCallback, JS_RequestInterruptCallbackCanWait};
use crate::jsapi::{JS_StackCapture_AllFrames, JS_StackCapture_MaxFrames};
use crate::jsapi::{PersistentRootedObjectVector, ReadOnlyCompileOptions, RootingContext};
use crate::jsapi::{SetWarningReporter, SourceText, ToBooleanSlow};
use crate::jsapi::{ToInt32Slow, ToInt64Slow, ToNumberSlow, ToStringSlow, ToUint16Slow};
use crate::jsapi::{ToUint32Slow, ToUint64Slow, ToWindowProxyIfWindowSlow};
use crate::jsval::ObjectValue;
use crate::panic::maybe_resume_unwind;
use log::{debug, warn};
use mozjs_sys::jsapi::JS::SavedFrameResult;
pub use mozjs_sys::jsgc::{GCMethods, IntoHandle, IntoMutableHandle};
pub use mozjs_sys::trace::Traceable as Trace;
use crate::rooted;
// 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:
// The JS engine permits us to set different stack limits for system code,
// trusted script, and untrusted script. We have tests that ensure that
// we can always execute 10 "heavy" (eval+with) stack frames deeper in
// privileged code. Our stack sizes vary greatly in different configurations,
// so satisfying those tests requires some care. Manual measurements of the
// number of heavy stack frames achievable gives us the following rough data,
// ordered by the effective categories in which they are grouped in the
// JS_SetNativeStackQuota call (which predates this analysis).
//
// (NB: These numbers may have drifted recently - see bug 938429)
// OSX 64-bit Debug: 7MB stack, 636 stack frames => ~11.3k per stack frame
// OSX64 Opt: 7MB stack, 2440 stack frames => ~3k per stack frame
//
// Linux 32-bit Debug: 2MB stack, 426 stack frames => ~4.8k per stack frame
// Linux 64-bit Debug: 4MB stack, 455 stack frames => ~9.0k per stack frame
//
// Windows (Opt+Debug): 900K stack, 235 stack frames => ~3.4k per stack frame
//
// Linux 32-bit Opt: 1MB stack, 272 stack frames => ~3.8k per stack frame
// Linux 64-bit Opt: 2MB stack, 316 stack frames => ~6.5k per stack frame
//
// 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
pub struct RealmOptions(*mut jsapi::RealmOptions);
impl Deref for RealmOptions {
type Target = jsapi::RealmOptions;
fn deref(&self) -> &Self::Target {
unsafe { &*self.0 }
}
}
impl DerefMut for RealmOptions {
fn deref_mut(&mut self) -> &mut Self::Target {
unsafe { &mut *self.0 }
}
}
impl Default for RealmOptions {
fn default() -> RealmOptions {
RealmOptions(unsafe { JS_NewRealmOptions() })
}
}
impl Drop for RealmOptions {
fn drop(&mut self) {
unsafe { DeleteRealmOptions(self.0) }
}
}
thread_local!(static CONTEXT: Cell<*mut JSContext> = Cell::new(ptr::null_mut()));
#[derive(PartialEq)]
enum EngineState {
Uninitialized,
InitFailed,
Initialized,
ShutDown,
}
static ENGINE_STATE: Mutex<EngineState> = Mutex::new(EngineState::Uninitialized);
#[derive(Debug)]
pub enum JSEngineError {
AlreadyInitialized,
AlreadyShutDown,
InitFailed,
}
/// A handle that must be kept alive in order to create new Runtimes.
/// When this handle is dropped, the engine is shut down and cannot
/// be reinitialized.
pub struct JSEngine {
/// The count of alive handles derived from this initialized instance.
outstanding_handles: Arc<AtomicU32>,
// Ensure this type cannot be sent between threads.
marker: PhantomData<*mut ()>,
}
pub struct JSEngineHandle(Arc<AtomicU32>);
impl Clone for JSEngineHandle {
fn clone(&self) -> JSEngineHandle {
self.0.fetch_add(1, Ordering::SeqCst);
JSEngineHandle(self.0.clone())
}
}
impl Drop for JSEngineHandle {
fn drop(&mut self) {
self.0.fetch_sub(1, Ordering::SeqCst);
}
}
impl JSEngine {
/// Initialize the JS engine to prepare for creating new JS runtimes.
pub fn init() -> Result<JSEngine, JSEngineError> {
let mut state = ENGINE_STATE.lock().unwrap();
match *state {
EngineState::Initialized => return Err(JSEngineError::AlreadyInitialized),
EngineState::InitFailed => return Err(JSEngineError::InitFailed),
EngineState::ShutDown => return Err(JSEngineError::AlreadyShutDown),
EngineState::Uninitialized => (),
}
if unsafe { !JS_Init() } {
*state = EngineState::InitFailed;
Err(JSEngineError::InitFailed)
} else {
*state = EngineState::Initialized;
Ok(JSEngine {
outstanding_handles: Arc::new(AtomicU32::new(0)),
marker: PhantomData,
})
}
}
pub fn can_shutdown(&self) -> bool {
self.outstanding_handles.load(Ordering::SeqCst) == 0
}
/// Create a handle to this engine.
pub fn handle(&self) -> JSEngineHandle {
self.outstanding_handles.fetch_add(1, Ordering::SeqCst);
JSEngineHandle(self.outstanding_handles.clone())
}
}
/// Shut down the JS engine, invalidating any existing runtimes and preventing
/// any new ones from being created.
impl Drop for JSEngine {
fn drop(&mut self) {
let mut state = ENGINE_STATE.lock().unwrap();
if *state == EngineState::Initialized {
assert_eq!(
self.outstanding_handles.load(Ordering::SeqCst),
0,
"There are outstanding JS engine handles"
);
*state = EngineState::ShutDown;
unsafe {
JS_ShutDown();
}
}
}
}
pub fn transform_str_to_source_text(source: &str) -> SourceText<Utf8Unit> {
SourceText {
units_: source.as_ptr() as *const _,
length_: source.len() as u32,
ownsUnits_: false,
_phantom_0: PhantomData,
}
}
pub fn transform_u16_to_source_text(source: &[u16]) -> SourceText<u16> {
SourceText {
units_: source.as_ptr() as *const _,
length_: source.len() as u32,
ownsUnits_: false,
_phantom_0: PhantomData,
}
}
/// A handle to a Runtime that will be used to create a new runtime in another
/// thread. This handle and the new runtime must be destroyed before the original
/// runtime can be dropped.
pub struct ParentRuntime {
/// Raw pointer to the underlying SpiderMonkey runtime.
parent: *mut JSRuntime,
/// Handle to ensure the JS engine remains running while this handle exists.
engine: JSEngineHandle,
/// The number of children of the runtime that created this ParentRuntime value.
children_of_parent: Arc<()>,
}
unsafe impl Send for ParentRuntime {}
/// A wrapper for the `JSContext` structure in SpiderMonkey.
pub struct Runtime {
/// Raw pointer to the underlying SpiderMonkey context.
cx: *mut JSContext,
/// The engine that this runtime is associated with.
engine: JSEngineHandle,
/// If this Runtime was created with a parent, this member exists to ensure
/// that that parent's count of outstanding children (see [outstanding_children])
/// remains accurate and will be automatically decreased when this Runtime value
/// is dropped.
_parent_child_count: Option<Arc<()>>,
/// The strong references to this value represent the number of child runtimes
/// that have been created using this Runtime as a parent. Since Runtime values
/// must be associated with a particular thread, we cannot simply use Arc<Runtime>
/// to represent the resulting ownership graph and risk destroying a Runtime on
/// the wrong thread.
outstanding_children: Arc<()>,
/// An `Option` that holds the same pointer as `cx`.
/// This is shared with all [`ThreadSafeJSContext`]s, so
/// they can detect when it's destroyed on the main thread.
thread_safe_handle: Arc<RwLock<Option<*mut JSContext>>>,
}
impl Runtime {
/// Get the `JSContext` for this thread.
pub fn get() -> Option<NonNull<JSContext>> {
let cx = CONTEXT.with(|context| context.get());
NonNull::new(cx)
}
/// Create a [`ThreadSafeJSContext`] that can detect when this `Runtime` is destroyed.
pub fn thread_safe_js_context(&self) -> ThreadSafeJSContext {
ThreadSafeJSContext(self.thread_safe_handle.clone())
}
/// Creates a new `JSContext`.
pub fn new(engine: JSEngineHandle) -> Runtime {
unsafe { Self::create(engine, None) }
}
/// Signal that a new child runtime will be created in the future, and ensure
/// that this runtime will not allow itself to be destroyed before the new
/// child runtime. Returns a handle that can be passed to `create_with_parent`
/// in order to create a new runtime on another thread that is associated with
/// this runtime.
pub fn prepare_for_new_child(&self) -> ParentRuntime {
ParentRuntime {
parent: self.rt(),
engine: self.engine.clone(),
children_of_parent: self.outstanding_children.clone(),
}
}
/// Creates a new `JSContext` with a parent runtime. If the parent does not outlive
/// the new runtime, its destructor will assert.
///
/// Unsafety:
/// If panicking does not abort the program, any threads with child runtimes will
/// continue executing after the thread with the parent runtime panics, but they
/// will be in an invalid and undefined state.
pub unsafe fn create_with_parent(parent: ParentRuntime) -> Runtime {
Self::create(parent.engine.clone(), Some(parent))
}
unsafe fn create(engine: JSEngineHandle, parent: Option<ParentRuntime>) -> Runtime {
let parent_runtime = parent.as_ref().map_or(ptr::null_mut(), |r| r.parent);
let js_context = JS_NewContext(default_heapsize + (ChunkSize as u32), parent_runtime);
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_AddExtraGCRootsTracer(js_context, Some(trace_traceables), ptr::null_mut());
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);
});
#[cfg(target_pointer_width = "64")]
let cache = crate::jsapi::__BindgenOpaqueArray::<u64, 2>::default();
#[cfg(target_pointer_width = "32")]
let cache = crate::jsapi::__BindgenOpaqueArray::<u32, 2>::default();
InitSelfHostedCode(js_context, cache, None);
SetWarningReporter(js_context, Some(report_warning));
Runtime {
engine,
_parent_child_count: parent.map(|p| p.children_of_parent),
cx: js_context,
outstanding_children: Arc::new(()),
thread_safe_handle: Arc::new(RwLock::new(Some(js_context))),
}
}
/// Returns the `JSRuntime` object.
pub fn rt(&self) -> *mut JSRuntime {
unsafe { JS_GetRuntime(self.cx) }
}
/// Returns the `JSContext` object.
pub fn cx(&self) -> *mut JSContext {
self.cx
}
pub fn evaluate_script(
&self,
glob: HandleObject,
script: &str,
filename: &str,
line_num: u32,
rval: MutableHandleValue,
) -> Result<(), ()> {
debug!(
"Evaluating script from {} with content {}",
filename, script
);
let _ac = JSAutoRealm::new(self.cx(), glob.get());
let options = unsafe { CompileOptionsWrapper::new(self.cx(), filename, line_num) };
unsafe {
let mut source = transform_str_to_source_text(&script);
if !Evaluate2(self.cx(), options.ptr, &mut source, rval.into()) {
debug!("...err!");
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) {
self.thread_safe_handle.write().unwrap().take();
assert_eq!(
Arc::strong_count(&self.outstanding_children),
1,
"This runtime still has live children."
);
unsafe {
JS_DestroyContext(self.cx);
CONTEXT.with(|context| {
assert_eq!(context.get(), self.cx);
context.set(ptr::null_mut());
});
}
}
}
/// A version of the [`JSContext`] that can be used from other threads and is thus
/// `Send` and `Sync`. This should only ever expose operations that are marked as
/// thread-safe by the SpiderMonkey API, ie ones that only atomic fields in JSContext.
#[derive(Clone)]
pub struct ThreadSafeJSContext(Arc<RwLock<Option<*mut JSContext>>>);
unsafe impl Send for ThreadSafeJSContext {}
unsafe impl Sync for ThreadSafeJSContext {}
impl ThreadSafeJSContext {
/// Call `JS_RequestInterruptCallback` from the SpiderMonkey API.
/// This is thread-safe according to
/// <https://searchfox.org/mozilla-central/rev/7a85a111b5f42cdc07f438e36f9597c4c6dc1d48/js/public/Interrupt.h#19>
pub fn request_interrupt_callback(&self) {
if let Some(&cx) = self.0.read().unwrap().as_ref() {
unsafe {
JS_RequestInterruptCallback(cx);
}
}
}
/// Call `JS_RequestInterruptCallbackCanWait` from the SpiderMonkey API.
/// This is thread-safe according to
/// <https://searchfox.org/mozilla-central/rev/7a85a111b5f42cdc07f438e36f9597c4c6dc1d48/js/public/Interrupt.h#19>
pub fn request_interrupt_callback_can_wait(&self) {
if let Some(&cx) = self.0.read().unwrap().as_ref() {
unsafe {
JS_RequestInterruptCallbackCanWait(cx);
}
}
}
}
const ChunkShift: usize = 20;
const ChunkSize: usize = 1 << ChunkShift;
#[cfg(target_pointer_width = "32")]
const ChunkLocationOffset: usize = ChunkSize - 2 * 4 - 8;
// ___________________________________________________________________________
// Wrappers around things in jsglue.cpp
pub struct RootedObjectVectorWrapper {
pub ptr: *mut 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) }
}
pub fn handle(&self) -> RawHandleObjectVector {
RawHandleObjectVector {
ptr: unsafe { GetObjectVectorAddress(self.ptr) },
}
}
}
impl Drop for RootedObjectVectorWrapper {
fn drop(&mut self) {
unsafe { DeleteRootedObjectVector(self.ptr) }
}
}
pub struct CompileOptionsWrapper {
pub ptr: *mut ReadOnlyCompileOptions,
}
impl CompileOptionsWrapper {
pub unsafe fn new(cx: *mut JSContext, filename: &str, line: u32) -> Self {
let filename_cstr = ffi::CString::new(filename.as_bytes()).unwrap();
let ptr = NewCompileOptions(cx, filename_cstr.as_ptr(), line);
assert!(!ptr.is_null());
Self { ptr }
}
}
impl Drop for CompileOptionsWrapper {
fn drop(&mut self) {
unsafe { DeleteCompileOptions(self.ptr) }
}
}
pub struct Stencil {
inner: already_AddRefed<CompilationStencil>,
}
/*unsafe impl Send for Stencil {}
unsafe impl Sync for Stencil {}*/
impl Drop for Stencil {
fn drop(&mut self) {
if self.is_null() {
return;
}
unsafe {
StencilRelease(self.inner.mRawPtr);
}
}
}
impl Deref for Stencil {
type Target = *mut CompilationStencil;
fn deref(&self) -> &Self::Target {
&self.inner.mRawPtr
}
}
impl Stencil {
pub fn is_null(&self) -> bool {
self.inner.mRawPtr.is_null()
}
}
// ___________________________________________________________________________
// Fast inline converters
#[inline]
pub unsafe fn ToBoolean(v: 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;
}
ToBooleanSlow(v.into())
}
#[inline]
pub unsafe fn ToNumber(cx: *mut JSContext, v: HandleValue) -> Result<f64, ()> {
let val = *v.ptr;
if val.is_number() {
return Ok(val.to_number());
}
let mut out = Default::default();
if ToNumberSlow(cx, v.into_handle(), &mut out) {
Ok(out)
} else {
Err(())
}
}
#[inline]
unsafe fn convert_from_int32<T: Default + Copy>(
cx: *mut JSContext,
v: HandleValue,
conv_fn: unsafe extern "C" fn(*mut JSContext, RawHandleValue, *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.into(), &mut out) {
Ok(out)
} else {
Err(())
}
}
#[inline]
pub unsafe fn ToInt32(cx: *mut JSContext, v: HandleValue) -> Result<i32, ()> {
convert_from_int32::<i32>(cx, v, ToInt32Slow)
}
#[inline]
pub unsafe fn ToUint32(cx: *mut JSContext, v: HandleValue) -> Result<u32, ()> {
convert_from_int32::<u32>(cx, v, ToUint32Slow)
}
#[inline]
pub unsafe fn ToUint16(cx: *mut JSContext, v: HandleValue) -> Result<u16, ()> {
convert_from_int32::<u16>(cx, v, ToUint16Slow)
}
#[inline]
pub unsafe fn ToInt64(cx: *mut JSContext, v: HandleValue) -> Result<i64, ()> {
convert_from_int32::<i64>(cx, v, ToInt64Slow)
}
#[inline]
pub unsafe fn ToUint64(cx: *mut JSContext, v: HandleValue) -> Result<u64, ()> {
convert_from_int32::<u64>(cx, v, ToUint64Slow)
}
#[inline]
pub unsafe fn ToString(cx: *mut JSContext, v: HandleValue) -> *mut JSString {
let val = *v.ptr;
if val.is_string() {
return val.to_string();
}
ToStringSlow(cx, v.into())
}
pub unsafe fn ToWindowProxyIfWindow(obj: *mut JSObject) -> *mut JSObject {
if is_window(obj) {
ToWindowProxyIfWindowSlow(obj)
} else {
obj
}
}
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.data_;
let fname = if !fnptr.is_null() {
let c_str = 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._base;
let msg_ptr = (*report)._base.message_.data_ as *const u8;
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 = str::from_utf8_unchecked(msg_slice);
warn!("Warning at {}:{}:{}: {}\n", fname, lineno, column, msg);
}
pub struct IdVector(*mut PersistentRootedIdVector);
impl IdVector {
pub unsafe fn new(cx: *mut JSContext) -> IdVector {
let vector = CreateRootedIdVector(cx);
assert!(!vector.is_null());
IdVector(vector)
}
pub fn handle_mut(&mut self) -> RawMutableHandleIdVector {
RawMutableHandleIdVector {
ptr: unsafe { GetIdVectorAddress(self.0) },
}
}
}
impl Drop for IdVector {
fn drop(&mut self) {
unsafe { DestroyRootedIdVector(self.0) }
}
}
impl Deref for IdVector {
type Target = [jsid];
fn deref(&self) -> &[jsid] {
unsafe {
let mut length = 0;
let pointer = SliceRootedIdVector(self.0, &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: HandleObject,
methods: &'static [JSFunctionSpec],
) -> Result<(), ()> {
assert!({
match methods.last() {
Some(&JSFunctionSpec {
name,
call,
nargs,
flags,
selfHostedName,
}) => {
name.string_.is_null()
&& call.is_zeroed()
&& nargs == 0
&& flags == 0
&& selfHostedName.is_null()
}
None => false,
}
});
JS_DefineFunctions(cx, obj.into(), 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: HandleObject,
properties: &'static [JSPropertySpec],
) -> Result<(), ()> {
assert!({
match properties.last() {
Some(spec) => spec.is_zeroed(),
None => false,
}
});
JS_DefineProperties(cx, obj.into(), 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,
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: c"Global".as_ptr(),
flags: JSCLASS_IS_GLOBAL
| ((JSCLASS_GLOBAL_SLOT_COUNT & JSCLASS_RESERVED_SLOTS_MASK)
<< JSCLASS_RESERVED_SLOTS_SHIFT),
cOps: &SIMPLE_GLOBAL_CLASS_OPS as *const JSClassOps,
spec: ptr::null(),
ext: ptr::null(),
oOps: ptr::null(),
};
#[inline]
unsafe fn get_object_group(obj: *mut JSObject) -> *mut BaseShape {
assert!(!obj.is_null());
let obj = obj as *mut Object;
(*(*obj).shape).base
}
#[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_realm(obj: *mut JSObject) -> *mut Realm {
(*get_object_group(obj)).realm
}
#[inline]
pub unsafe fn get_context_realm(cx: *mut JSContext) -> *mut Realm {
let cx = cx as *mut RootingContext;
(*cx).realm_
}
#[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_window(obj: *mut JSObject) -> bool {
(*get_object_class(obj)).flags & JSCLASS_IS_GLOBAL != 0 && IsWindowSlow(obj)
}
#[inline]
pub unsafe fn try_to_outerize(mut rval: MutableHandleValue) {
let obj = rval.to_object();
if is_window(obj) {
let obj = ToWindowProxyIfWindowSlow(obj);
assert!(!obj.is_null());
rval.set(ObjectValue(&mut *obj));
}
}
#[inline]
pub unsafe fn try_to_outerize_object(mut rval: MutableHandleObject) {
if is_window(*rval) {
let obj = ToWindowProxyIfWindowSlow(*rval);
assert!(!obj.is_null());
rval.set(obj);
}
}
#[inline]
pub unsafe fn maybe_wrap_object(cx: *mut JSContext, obj: MutableHandleObject) {
if get_object_realm(*obj) != get_context_realm(cx) {
assert!(JS_WrapObject(cx, obj.into()));
}
try_to_outerize_object(obj);
}
#[inline]
pub unsafe fn maybe_wrap_object_value(cx: *mut JSContext, rval: MutableHandleValue) {
assert!(rval.is_object());
let obj = rval.to_object();
if get_object_realm(obj) != get_context_realm(cx) {
assert!(JS_WrapValue(cx, rval.into()));
} else if is_dom_object(obj) {
try_to_outerize(rval);
}
}
#[inline]
pub unsafe fn maybe_wrap_object_or_null_value(cx: *mut JSContext, rval: 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: MutableHandleValue) {
if rval.is_string() {
assert!(JS_WrapValue(cx, rval.into()));
} else if rval.is_object() {
maybe_wrap_object_value(cx, rval);
}
}
/// Like `JSJitInfo::new_bitfield_1`, but usable in `const` contexts.
#[macro_export]
macro_rules! new_jsjitinfo_bitfield_1 {
(
$type_: expr,
$aliasSet_: expr,
$returnType_: expr,
$isInfallible: expr,
$isMovable: expr,
$isEliminatable: expr,
$isAlwaysInSlot: expr,
$isLazilyCachedInSlot: expr,
$isTypedMethod: expr,
$slotIndex: expr,
) => {
0 | (($type_ as u32) << 0u32)
| (($aliasSet_ as u32) << 4u32)
| (($returnType_ as u32) << 8u32)
| (($isInfallible as u32) << 16u32)
| (($isMovable as u32) << 17u32)
| (($isEliminatable as u32) << 18u32)
| (($isAlwaysInSlot as u32) << 19u32)
| (($isLazilyCachedInSlot as u32) << 20u32)
| (($isTypedMethod as u32) << 21u32)
| (($slotIndex as u32) << 22u32)
};
}
#[derive(Debug, Default)]
pub struct ScriptedCaller {
pub filename: String,
pub line: u32,
pub col: u32,
}
pub unsafe fn describe_scripted_caller(cx: *mut JSContext) -> Result<ScriptedCaller, ()> {
let mut buf = [0; 1024];
let mut line = 0;
let mut col = 0;
if !DescribeScriptedCaller(cx, buf.as_mut_ptr(), buf.len(), &mut line, &mut col) {
return Err(());
}
let filename = CStr::from_ptr((&buf) as *const _ as *const _);
Ok(ScriptedCaller {
filename: String::from_utf8_lossy(filename.to_bytes()).into_owned(),
line,
col,
})
}
pub struct CapturedJSStack<'a> {
cx: *mut JSContext,
stack: RootedGuard<'a, *mut JSObject>,
}
impl<'a> CapturedJSStack<'a> {
pub unsafe fn new(
cx: *mut JSContext,
mut guard: RootedGuard<'a, *mut JSObject>,
max_frame_count: Option<u32>,
) -> Option<Self> {
let ref mut stack_capture = MaybeUninit::uninit();
match max_frame_count {
None => JS_StackCapture_AllFrames(stack_capture.as_mut_ptr()),
Some(count) => JS_StackCapture_MaxFrames(count, stack_capture.as_mut_ptr()),
};
let ref mut stack_capture = stack_capture.assume_init();
if !CaptureCurrentStack(cx, guard.handle_mut().raw(), stack_capture) {