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//! The ECMAScript context.
mod hooks;
#[cfg(feature = "intl")]
pub(crate) mod icu;
pub mod intrinsics;
use boa_parser::source::ReadChar;
pub use hooks::{DefaultHooks, HostHooks};
#[cfg(feature = "intl")]
pub use icu::IcuError;
use intrinsics::Intrinsics;
use std::{cell::Cell, path::Path, rc::Rc};
use crate::{
builtins,
class::{Class, ClassBuilder},
job::{JobQueue, NativeJob, SimpleJobQueue},
js_string,
module::{IdleModuleLoader, ModuleLoader, SimpleModuleLoader},
native_function::NativeFunction,
object::{shape::RootShape, FunctionObjectBuilder, JsObject},
optimizer::{Optimizer, OptimizerOptions, OptimizerStatistics},
property::{Attribute, PropertyDescriptor, PropertyKey},
realm::Realm,
script::Script,
vm::{ActiveRunnable, CallFrame, Vm},
JsNativeError, JsResult, JsString, JsValue, Source,
};
use boa_ast::StatementList;
use boa_interner::Interner;
use boa_profiler::Profiler;
use crate::vm::RuntimeLimits;
use self::intrinsics::StandardConstructor;
thread_local! {
static CANNOT_BLOCK_COUNTER: Cell<u64> = Cell::new(0);
}
/// ECMAScript context. It is the primary way to interact with the runtime.
///
/// `Context`s constructed in a thread share the same runtime, therefore it
/// is possible to share objects from one context to another context, but they
/// have to be in the same thread.
///
/// # Examples
///
/// ## Execute Function of Script File
///
/// ```rust
/// use boa_engine::{
/// js_string,
/// object::ObjectInitializer,
/// property::{Attribute, PropertyDescriptor},
/// Context, Source,
/// };
///
/// let script = r#"
/// function test(arg1) {
/// if(arg1 != null) {
/// return arg1.x;
/// }
/// return 112233;
/// }
/// "#;
///
/// let mut context = Context::default();
///
/// // Populate the script definition to the context.
/// context.eval(Source::from_bytes(script)).unwrap();
///
/// // Create an object that can be used in eval calls.
/// let arg = ObjectInitializer::new(&mut context)
/// .property(js_string!("x"), 12, Attribute::READONLY)
/// .build();
/// context
/// .register_global_property(js_string!("arg"), arg, Attribute::all())
/// .expect("property shouldn't exist");
///
/// let value = context.eval(Source::from_bytes("test(arg)")).unwrap();
///
/// assert_eq!(value.as_number(), Some(12.0))
/// ```
pub struct Context {
/// String interner in the context.
interner: Interner,
/// Execute in strict mode,
strict: bool,
/// Number of instructions remaining before a forced exit
#[cfg(feature = "fuzz")]
pub(crate) instructions_remaining: usize,
pub(crate) vm: Vm,
pub(crate) kept_alive: Vec<JsObject>,
can_block: bool,
/// Intl data provider.
#[cfg(feature = "intl")]
intl_provider: icu::IntlProvider,
host_hooks: &'static dyn HostHooks,
job_queue: Rc<dyn JobQueue>,
module_loader: Rc<dyn ModuleLoader>,
optimizer_options: OptimizerOptions,
root_shape: RootShape,
/// Unique identifier for each parser instance used during the context lifetime.
parser_identifier: u32,
}
impl std::fmt::Debug for Context {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
let mut debug = f.debug_struct("Context");
debug
.field("realm", &self.vm.realm)
.field("interner", &self.interner)
.field("vm", &self.vm)
.field("strict", &self.strict)
.field("promise_job_queue", &"JobQueue")
.field("hooks", &"HostHooks")
.field("module_loader", &"ModuleLoader")
.field("optimizer_options", &self.optimizer_options);
#[cfg(feature = "intl")]
debug.field("intl_provider", &self.intl_provider);
debug.finish_non_exhaustive()
}
}
impl Drop for Context {
fn drop(&mut self) {
if !self.can_block {
CANNOT_BLOCK_COUNTER.set(CANNOT_BLOCK_COUNTER.get() - 1);
}
}
}
impl Default for Context {
fn default() -> Self {
ContextBuilder::default()
.build()
.expect("Building the default context should not fail")
}
}
// ==== Public API ====
impl Context {
/// Create a new [`ContextBuilder`] to specify the [`Interner`] and/or
/// the icu data provider.
#[must_use]
pub fn builder() -> ContextBuilder {
ContextBuilder::default()
}
/// Evaluates the given source by compiling down to bytecode, then interpreting the
/// bytecode into a value.
///
/// # Examples
/// ```
/// # use boa_engine::{Context, Source};
/// let mut context = Context::default();
///
/// let source = Source::from_bytes("1 + 3");
/// let value = context.eval(source).unwrap();
///
/// assert!(value.is_number());
/// assert_eq!(value.as_number().unwrap(), 4.0);
/// ```
///
/// Note that this won't run any scheduled promise jobs; you need to call [`Context::run_jobs`]
/// on the context or [`JobQueue::run_jobs`] on the provided queue to run them.
#[allow(clippy::unit_arg, dropping_copy_types)]
pub fn eval<R: ReadChar>(&mut self, src: Source<'_, R>) -> JsResult<JsValue> {
let main_timer = Profiler::global().start_event("Script evaluation", "Main");
let result = Script::parse(src, None, self)?.evaluate(self);
// The main_timer needs to be dropped before the Profiler is.
drop(main_timer);
Profiler::global().drop();
result
}
/// Applies optimizations to the [`StatementList`] inplace.
pub fn optimize_statement_list(
&mut self,
statement_list: &mut StatementList,
) -> OptimizerStatistics {
let mut optimizer = Optimizer::new(self);
optimizer.apply(statement_list)
}
/// Register a global property.
///
/// It will return an error if the property is already defined.
///
/// # Example
/// ```
/// use boa_engine::{
/// js_string,
/// object::ObjectInitializer,
/// property::{Attribute, PropertyDescriptor},
/// Context,
/// };
///
/// let mut context = Context::default();
///
/// context
/// .register_global_property(
/// js_string!("myPrimitiveProperty"),
/// 10,
/// Attribute::all(),
/// )
/// .expect("property shouldn't exist");
///
/// let object = ObjectInitializer::new(&mut context)
/// .property(js_string!("x"), 0, Attribute::all())
/// .property(js_string!("y"), 1, Attribute::all())
/// .build();
/// context
/// .register_global_property(
/// js_string!("myObjectProperty"),
/// object,
/// Attribute::all(),
/// )
/// .expect("property shouldn't exist");
/// ```
pub fn register_global_property<K, V>(
&mut self,
key: K,
value: V,
attribute: Attribute,
) -> JsResult<()>
where
K: Into<PropertyKey>,
V: Into<JsValue>,
{
self.global_object().define_property_or_throw(
key,
PropertyDescriptor::builder()
.value(value)
.writable(attribute.writable())
.enumerable(attribute.enumerable())
.configurable(attribute.configurable()),
self,
)?;
Ok(())
}
/// Register a global native callable.
///
/// The function will be both `constructable` (call with `new <name>()`) and `callable` (call
/// with `<name>()`).
///
/// The function will be bound to the global object with `writable`, `non-enumerable`
/// and `configurable` attributes. The same as when you create a function in JavaScript.
///
/// # Note
///
/// If you wish to only create the function object without binding it to the global object, you
/// can use the [`FunctionObjectBuilder`] API.
pub fn register_global_callable(
&mut self,
name: JsString,
length: usize,
body: NativeFunction,
) -> JsResult<()> {
let function = FunctionObjectBuilder::new(self.realm(), body)
.name(name.clone())
.length(length)
.constructor(true)
.build();
self.global_object().define_property_or_throw(
name,
PropertyDescriptor::builder()
.value(function)
.writable(true)
.enumerable(false)
.configurable(true),
self,
)?;
Ok(())
}
/// Register a global native function that is not a constructor.
///
/// The function will be bound to the global object with `writable`, `non-enumerable`
/// and `configurable` attributes. The same as when you create a function in JavaScript.
///
/// # Note
///
/// The difference to [`Context::register_global_callable`] is, that the function will not be
/// `constructable`. Usage of the function as a constructor will produce a `TypeError`.
pub fn register_global_builtin_callable(
&mut self,
name: JsString,
length: usize,
body: NativeFunction,
) -> JsResult<()> {
let function = FunctionObjectBuilder::new(self.realm(), body)
.name(name.clone())
.length(length)
.constructor(false)
.build();
self.global_object().define_property_or_throw(
name,
PropertyDescriptor::builder()
.value(function)
.writable(true)
.enumerable(false)
.configurable(true),
self,
)?;
Ok(())
}
/// Registers a global class `C` in the currently active realm.
///
/// Errors if the class has already been registered.
///
/// # Example
/// ```ignore
/// #[derive(Debug, Trace, Finalize)]
/// struct MyClass;
///
/// impl Class for MyClass {
/// // ...
/// }
///
/// context.register_global_class::<MyClass>()?;
/// ```
pub fn register_global_class<C: Class>(&mut self) -> JsResult<()> {
if self.realm().has_class::<C>() {
return Err(JsNativeError::typ()
.with_message("cannot register a class twice")
.into());
}
let mut class_builder = ClassBuilder::new::<C>(self);
C::init(&mut class_builder)?;
let class = class_builder.build();
let property = PropertyDescriptor::builder()
.value(class.constructor())
.writable(C::ATTRIBUTES.writable())
.enumerable(C::ATTRIBUTES.enumerable())
.configurable(C::ATTRIBUTES.configurable());
self.global_object()
.define_property_or_throw(js_string!(C::NAME), property, self)?;
self.realm().register_class::<C>(class);
Ok(())
}
/// Removes the global class `C` from the currently active realm, returning the constructor
/// and prototype of the class if `C` was registered.
///
/// # Note
///
/// This makes the constructor return an error on further calls, but note that this won't protect
/// static properties from being accessed within variables that stored the constructor before being
/// unregistered. If you need that functionality, you can use a static accessor that first checks
/// if the class is registered ([`Context::has_global_class`]) before returning the static value.
///
/// # Example
/// ```ignore
/// #[derive(Debug, Trace, Finalize)]
/// struct MyClass;
///
/// impl Class for MyClass {
/// // ...
/// }
///
/// context.register_global_class::<MyClass>()?;
/// // ... code
/// context.unregister_global_class::<MyClass>()?;
/// ```
pub fn unregister_global_class<C: Class>(&mut self) -> JsResult<Option<StandardConstructor>> {
self.global_object()
.delete_property_or_throw(js_string!(C::NAME), self)?;
Ok(self.realm().unregister_class::<C>())
}
/// Checks if the currently active realm has the global class `C` registered.
#[must_use]
pub fn has_global_class<C: Class>(&self) -> bool {
self.realm().has_class::<C>()
}
/// Gets the constructor and prototype of the global class `C` if the currently active realm has
/// that class registered.
#[must_use]
pub fn get_global_class<C: Class>(&self) -> Option<StandardConstructor> {
self.realm().get_class::<C>()
}
/// Gets the string interner.
#[inline]
#[must_use]
pub const fn interner(&self) -> &Interner {
&self.interner
}
/// Gets a mutable reference to the string interner.
#[inline]
pub fn interner_mut(&mut self) -> &mut Interner {
&mut self.interner
}
/// Returns the global object.
#[inline]
#[must_use]
pub fn global_object(&self) -> JsObject {
self.vm.realm.global_object().clone()
}
/// Returns the currently active intrinsic constructors and objects.
#[inline]
#[must_use]
pub fn intrinsics(&self) -> &Intrinsics {
self.vm.realm.intrinsics()
}
/// Returns the currently active realm.
#[inline]
#[must_use]
pub const fn realm(&self) -> &Realm {
&self.vm.realm
}
/// Set the value of trace on the context
#[cfg(feature = "trace")]
#[inline]
pub fn set_trace(&mut self, trace: bool) {
self.vm.trace = trace;
}
/// Get optimizer options.
#[inline]
#[must_use]
pub const fn optimizer_options(&self) -> OptimizerOptions {
self.optimizer_options
}
/// Enable or disable optimizations
#[inline]
pub fn set_optimizer_options(&mut self, optimizer_options: OptimizerOptions) {
self.optimizer_options = optimizer_options;
}
/// Changes the strictness mode of the context.
#[inline]
pub fn strict(&mut self, strict: bool) {
self.strict = strict;
}
/// Enqueues a [`NativeJob`] on the [`JobQueue`].
#[inline]
pub fn enqueue_job(&mut self, job: NativeJob) {
self.job_queue().enqueue_promise_job(job, self);
}
/// Runs all the jobs in the job queue.
#[inline]
pub fn run_jobs(&mut self) {
self.job_queue().run_jobs(self);
self.clear_kept_objects();
}
/// Asynchronously runs all the jobs in the job queue.
///
/// # Note
///
/// Concurrent job execution cannot be guaranteed by the engine, since this depends on the
/// specific handling of each [`JobQueue`]. If you want to execute jobs concurrently, you must
/// provide a custom implementor of `JobQueue` to the context.
#[allow(clippy::future_not_send)]
pub async fn run_jobs_async(&mut self) {
self.job_queue().run_jobs_async(self).await;
self.clear_kept_objects();
}
/// Abstract operation [`ClearKeptObjects`][clear].
///
/// Clears all objects maintained alive by calls to the [`AddToKeptObjects`][add] abstract
/// operation, used within the [`WeakRef`][weak] constructor.
///
/// [clear]: https://tc39.es/ecma262/multipage/executable-code-and-execution-contexts.html#sec-clear-kept-objects
/// [add]: https://tc39.es/ecma262/multipage/executable-code-and-execution-contexts.html#sec-addtokeptobjects
/// [weak]: https://tc39.es/ecma262/multipage/managing-memory.html#sec-weak-ref-objects
#[inline]
pub fn clear_kept_objects(&mut self) {
self.kept_alive.clear();
}
/// Retrieves the current stack trace of the context.
#[inline]
pub fn stack_trace(&self) -> impl Iterator<Item = &CallFrame> {
self.vm.frames.iter().rev()
}
/// Replaces the currently active realm with `realm`, and returns the old realm.
#[inline]
pub fn enter_realm(&mut self, realm: Realm) -> Realm {
self.vm
.environments
.replace_global(realm.environment().clone());
std::mem::replace(&mut self.vm.realm, realm)
}
/// Create a new Realm with the default global bindings.
pub fn create_realm(&mut self) -> JsResult<Realm> {
let realm = Realm::create(self.host_hooks, &self.root_shape)?;
let old_realm = self.enter_realm(realm);
builtins::set_default_global_bindings(self)?;
Ok(self.enter_realm(old_realm))
}
/// Get the [`RootShape`].
#[inline]
#[must_use]
pub const fn root_shape(&self) -> &RootShape {
&self.root_shape
}
/// Gets the host hooks.
#[inline]
#[must_use]
pub fn host_hooks(&self) -> &'static dyn HostHooks {
self.host_hooks
}
/// Gets the job queue.
#[inline]
#[must_use]
pub fn job_queue(&self) -> Rc<dyn JobQueue> {
self.job_queue.clone()
}
/// Gets the module loader.
#[must_use]
pub fn module_loader(&self) -> Rc<dyn ModuleLoader> {
self.module_loader.clone()
}
/// Get the [`RuntimeLimits`].
#[inline]
#[must_use]
pub const fn runtime_limits(&self) -> RuntimeLimits {
self.vm.runtime_limits
}
/// Set the [`RuntimeLimits`].
#[inline]
pub fn set_runtime_limits(&mut self, runtime_limits: RuntimeLimits) {
self.vm.runtime_limits = runtime_limits;
}
/// Get a mutable reference to the [`RuntimeLimits`].
#[inline]
pub fn runtime_limits_mut(&mut self) -> &mut RuntimeLimits {
&mut self.vm.runtime_limits
}
/// Returns `true` if this context can be suspended by an `Atomics.wait` call.
#[inline]
#[must_use]
pub fn can_block(&self) -> bool {
self.can_block
}
}
// ==== Private API ====
impl Context {
/// Swaps the currently active realm with `realm`.
pub(crate) fn swap_realm(&mut self, realm: &mut Realm) {
std::mem::swap(&mut self.vm.realm, realm);
}
/// Increment and get the parser identifier.
pub(crate) fn next_parser_identifier(&mut self) -> u32 {
self.parser_identifier += 1;
self.parser_identifier
}
/// `CanDeclareGlobalFunction ( N )`
///
/// More information:
/// - [ECMAScript reference][spec]
///
/// [spec]: https://tc39.es/ecma262/#sec-candeclareglobalfunction
pub(crate) fn can_declare_global_function(&mut self, name: &JsString) -> JsResult<bool> {
// 1. Let ObjRec be envRec.[[ObjectRecord]].
// 2. Let globalObject be ObjRec.[[BindingObject]].
let global_object = self.realm().global_object().clone();
// 3. Let existingProp be ? globalObject.[[GetOwnProperty]](N).
let name = name.clone().into();
let existing_prop = global_object.__get_own_property__(&name, &mut self.into())?;
// 4. If existingProp is undefined, return ? IsExtensible(globalObject).
let Some(existing_prop) = existing_prop else {
return global_object.is_extensible(self);
};
// 5. If existingProp.[[Configurable]] is true, return true.
if existing_prop.configurable() == Some(true) {
return Ok(true);
}
// 6. If IsDataDescriptor(existingProp) is true and existingProp has attribute values { [[Writable]]: true, [[Enumerable]]: true }, return true.
if existing_prop.is_data_descriptor()
&& existing_prop.writable() == Some(true)
&& existing_prop.enumerable() == Some(true)
{
return Ok(true);
}
// 7. Return false.
Ok(false)
}
/// `CanDeclareGlobalVar ( N )`
///
/// More information:
/// - [ECMAScript reference][spec]
///
/// [spec]: https://tc39.es/ecma262/#sec-candeclareglobalvar
pub(crate) fn can_declare_global_var(&mut self, name: &JsString) -> JsResult<bool> {
// 1. Let ObjRec be envRec.[[ObjectRecord]].
// 2. Let globalObject be ObjRec.[[BindingObject]].
let global_object = self.realm().global_object().clone();
// 3. Let hasProperty be ? HasOwnProperty(globalObject, N).
let has_property = global_object.has_own_property(name.clone(), self)?;
// 4. If hasProperty is true, return true.
if has_property {
return Ok(true);
}
// 5. Return ? IsExtensible(globalObject).
global_object.is_extensible(self)
}
/// `CreateGlobalVarBinding ( N, D )`
///
/// More information:
/// - [ECMAScript reference][spec]
///
/// [spec]: https://tc39.es/ecma262/#sec-createglobalvarbinding
pub(crate) fn create_global_var_binding(
&mut self,
name: JsString,
configurable: bool,
) -> JsResult<()> {
// 1. Let ObjRec be envRec.[[ObjectRecord]].
// 2. Let globalObject be ObjRec.[[BindingObject]].
let global_object = self.realm().global_object().clone();
// 3. Let hasProperty be ? HasOwnProperty(globalObject, N).
let has_property = global_object.has_own_property(name.clone(), self)?;
// 4. Let extensible be ? IsExtensible(globalObject).
let extensible = global_object.is_extensible(self)?;
// 5. If hasProperty is false and extensible is true, then
if !has_property && extensible {
// a. Perform ? ObjRec.CreateMutableBinding(N, D).
// b. Perform ? ObjRec.InitializeBinding(N, undefined).
global_object.define_property_or_throw(
name,
PropertyDescriptor::builder()
.value(JsValue::undefined())
.writable(true)
.enumerable(true)
.configurable(configurable)
.build(),
self,
)?;
}
// 6. If envRec.[[VarNames]] does not contain N, then
// a. Append N to envRec.[[VarNames]].
// 7. Return unused.
Ok(())
}
/// `CreateGlobalFunctionBinding ( N, V, D )`
///
/// More information:
/// - [ECMAScript reference][spec]
///
/// [spec]: https://tc39.es/ecma262/#sec-createglobalfunctionbinding
pub(crate) fn create_global_function_binding(
&mut self,
name: JsString,
function: JsObject,
configurable: bool,
) -> JsResult<()> {
// 1. Let ObjRec be envRec.[[ObjectRecord]].
// 2. Let globalObject be ObjRec.[[BindingObject]].
let global_object = self.realm().global_object().clone();
// 3. Let existingProp be ? globalObject.[[GetOwnProperty]](N).
let existing_prop =
global_object.__get_own_property__(&name.clone().into(), &mut self.into())?;
// 4. If existingProp is undefined or existingProp.[[Configurable]] is true, then
let desc = if existing_prop.is_none()
|| existing_prop.and_then(|p| p.configurable()) == Some(true)
{
// a. Let desc be the PropertyDescriptor { [[Value]]: V, [[Writable]]: true, [[Enumerable]]: true, [[Configurable]]: D }.
PropertyDescriptor::builder()
.value(function.clone())
.writable(true)
.enumerable(true)
.configurable(configurable)
.build()
}
// 5. Else,
else {
// a. Let desc be the PropertyDescriptor { [[Value]]: V }.
PropertyDescriptor::builder()
.value(function.clone())
.build()
};
// 6. Perform ? DefinePropertyOrThrow(globalObject, N, desc).
global_object.define_property_or_throw(name.clone(), desc, self)?;
// 7. Perform ? Set(globalObject, N, V, false).
global_object.set(name, function, false, self)?;
// 8. If envRec.[[VarNames]] does not contain N, then
// a. Append N to envRec.[[VarNames]].
// 9. Return unused.
Ok(())
}
/// `HasRestrictedGlobalProperty ( N )`
///
/// More information:
/// - [ECMAScript reference][spec]
///
/// [spec]: https://tc39.es/ecma262/#sec-hasrestrictedglobalproperty
pub(crate) fn has_restricted_global_property(&mut self, name: &JsString) -> JsResult<bool> {
// 1. Let ObjRec be envRec.[[ObjectRecord]].
// 2. Let globalObject be ObjRec.[[BindingObject]].
let global_object = self.realm().global_object().clone();
// 3. Let existingProp be ? globalObject.[[GetOwnProperty]](N).
let name = name.clone().into();
let existing_prop = global_object.__get_own_property__(&name, &mut self.into())?;
// 4. If existingProp is undefined, return false.
let Some(existing_prop) = existing_prop else {
return Ok(false);
};
// 5. If existingProp.[[Configurable]] is true, return false.
if existing_prop.configurable() == Some(true) {
return Ok(false);
}
// 6. Return true.
Ok(true)
}
/// Returns `true` if this context is in strict mode.
pub(crate) const fn is_strict(&self) -> bool {
self.strict
}
/// `9.4.1 GetActiveScriptOrModule ( )`
///
/// More information:
/// - [ECMAScript reference][spec]
///
/// [spec]: https://tc39.es/ecma262/#sec-getactivescriptormodule
pub(crate) fn get_active_script_or_module(&self) -> Option<ActiveRunnable> {
// 1. If the execution context stack is empty, return null.
// 2. Let ec be the topmost execution context on the execution context stack whose ScriptOrModule component is not null.
// 3. If no such execution context exists, return null. Otherwise, return ec's ScriptOrModule.
self.vm
.frames
.iter()
.rev()
.find_map(|frame| frame.active_runnable.clone())
}
/// Get `active function object`
///
/// More information:
/// - [ECMAScript reference][spec]
///
/// [spec]: https://tc39.es/ecma262/#active-function-object
pub(crate) fn active_function_object(&self) -> Option<JsObject> {
if self.vm.native_active_function.is_some() {
return self.vm.native_active_function.clone();
}
if let Some(frame) = self.vm.frames.last() {
return frame.function(&self.vm);
}
None
}
}
impl Context {
/// Creates a `ContextCleanupGuard` that executes some cleanup after being dropped.
pub(crate) fn guard<F>(&mut self, cleanup: F) -> ContextCleanupGuard<'_, F>
where
F: FnOnce(&mut Context) + 'static,
{
ContextCleanupGuard::new(self, cleanup)
}
/// Get the Intl data provider.
#[cfg(feature = "intl")]
pub(crate) const fn intl_provider(&self) -> &icu::IntlProvider {
&self.intl_provider
}
}
/// Builder for the [`Context`] type.
///
/// This builder allows custom initialization of the [`Interner`] within
/// the context.
#[derive(Default)]
pub struct ContextBuilder {
interner: Option<Interner>,
host_hooks: Option<&'static dyn HostHooks>,
job_queue: Option<Rc<dyn JobQueue>>,
module_loader: Option<Rc<dyn ModuleLoader>>,
can_block: bool,
#[cfg(feature = "intl")]
icu: Option<icu::IntlProvider>,
#[cfg(feature = "fuzz")]
instructions_remaining: usize,
}
impl std::fmt::Debug for ContextBuilder {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
#[derive(Clone, Copy, Debug)]
struct JobQueue;
#[derive(Clone, Copy, Debug)]
struct HostHooks;
#[derive(Clone, Copy, Debug)]
struct ModuleLoader;
let mut out = f.debug_struct("ContextBuilder");
out.field("interner", &self.interner)
.field("host_hooks", &self.host_hooks.as_ref().map(|_| HostHooks))
.field("job_queue", &self.job_queue.as_ref().map(|_| JobQueue))
.field(
"module_loader",
&self.module_loader.as_ref().map(|_| ModuleLoader),
)
.field("can_block", &self.can_block);
#[cfg(feature = "intl")]
out.field("icu", &self.icu);
#[cfg(feature = "fuzz")]
out.field("instructions_remaining", &self.instructions_remaining);
out.finish()
}
}
impl ContextBuilder {
/// Creates a new [`ContextBuilder`] with a default empty [`Interner`]
/// and a default `BoaProvider` if the `intl` feature is enabled.
#[must_use]
pub fn new() -> Self {
Self::default()
}
/// Initializes the context [`Interner`] to the provided interner.
///
/// This is useful when you want to initialize an [`Interner`] with
/// a collection of words before parsing.
#[must_use]
#[allow(clippy::missing_const_for_fn)]
pub fn interner(mut self, interner: Interner) -> Self {
self.interner = Some(interner);
self
}
/// Provides a [`BufferProvider`] data provider to the [`Context`].
///
/// This function is only available if the `intl` feature is enabled.
///
/// # Errors
///
/// This returns `Err` if the provided provider doesn't have the required locale information
/// to construct both a [`LocaleCanonicalizer`] and a [`LocaleExpander`]. Note that this doesn't
/// mean that the provider will successfully construct all `Intl` services; that check is made
/// until the creation of an instance of a service.
///
/// [`LocaleCanonicalizer`]: icu_locid_transform::LocaleCanonicalizer
/// [`LocaleExpander`]: icu_locid_transform::LocaleExpander
/// [`BufferProvider`]: icu_provider::BufferProvider
#[cfg(feature = "intl")]
pub fn icu_buffer_provider<T: icu_provider::BufferProvider + 'static>(
mut self,
provider: T,
) -> Result<Self, IcuError> {
self.icu = Some(icu::IntlProvider::try_new_with_buffer_provider(provider)?);
Ok(self)
}
/// Provides an [`AnyProvider`] data provider to the [`Context`].
///
/// This function is only available if the `intl` feature is enabled.
///
/// # Errors
///
/// This returns `Err` if the provided provider doesn't have the required locale information
/// to construct both a [`LocaleCanonicalizer`] and a [`LocaleExpander`]. Note that this doesn't
/// mean that the provider will successfully construct all `Intl` services; that check is made
/// until the creation of an instance of a service.
///
/// [`LocaleCanonicalizer`]: icu_locid_transform::LocaleCanonicalizer
/// [`LocaleExpander`]: icu_locid_transform::LocaleExpander
/// [`AnyProvider`]: icu_provider::AnyProvider
#[cfg(feature = "intl")]
pub fn icu_any_provider<T: icu_provider::AnyProvider + 'static>(
mut self,
provider: T,
) -> Result<Self, IcuError> {
self.icu = Some(icu::IntlProvider::try_new_with_any_provider(provider)?);
Ok(self)
}
/// Initializes the [`HostHooks`] for the context.
///
/// [`Host Hooks`]: https://tc39.es/ecma262/#sec-host-hooks-summary
#[must_use]
pub fn host_hooks<H: HostHooks + 'static>(mut self, host_hooks: &'static H) -> Self {
self.host_hooks = Some(host_hooks);
self
}
/// Initializes the [`JobQueue`] for the context.
#[must_use]
pub fn job_queue<Q: JobQueue + 'static>(mut self, job_queue: Rc<Q>) -> Self {
self.job_queue = Some(job_queue);
self
}
/// Initializes the [`ModuleLoader`] for the context.
#[must_use]
pub fn module_loader<M: ModuleLoader + 'static>(mut self, module_loader: Rc<M>) -> Self {
self.module_loader = Some(module_loader);
self
}
/// [`AgentCanSuspend ( )`][spec] aka `[[CanBlock]]`
///
/// Defines if this context can be suspended by calls to the [`Atomics.wait`][wait] function.
///
/// # Note
///
/// By the specification, multiple agents cannot share the same thread if any of them has its
/// `[[CanBlock]]` field set to true. The builder will verify at build time that all contexts on
/// the current thread fulfill this requisite.
///
/// [spec]: https://tc39.es/ecma262/#sec-agentcansuspend
/// [wait]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Atomics/wait
#[must_use]
pub const fn can_block(mut self, can_block: bool) -> Self {
self.can_block = can_block;
self
}
/// Specifies the number of instructions remaining to the [`Context`].
///
/// This function is only available if the `fuzz` feature is enabled.
#[cfg(feature = "fuzz")]
#[must_use]
pub const fn instructions_remaining(mut self, instructions_remaining: usize) -> Self {
self.instructions_remaining = instructions_remaining;
self
}
/// Builds a new [`Context`] with the provided parameters, and defaults
/// all missing parameters to their default values.
// TODO: try to use a custom error here, since most of the `JsError` APIs
// require having a `Context` in the first place.
pub fn build(self) -> JsResult<Context> {
if self.can_block {
if CANNOT_BLOCK_COUNTER.get() > 0 {
return Err(JsNativeError::typ()
.with_message(
"a context that can block must be the only active context in its current thread",
)
.into());
}
} else {
CANNOT_BLOCK_COUNTER.set(CANNOT_BLOCK_COUNTER.get() + 1);
}
let root_shape = RootShape::default();
let host_hooks = self.host_hooks.unwrap_or(&DefaultHooks);
let realm = Realm::create(host_hooks, &root_shape)?;
let vm = Vm::new(realm);
let module_loader: Rc<dyn ModuleLoader> = if let Some(loader) = self.module_loader {
loader
} else if let Ok(loader) = SimpleModuleLoader::new(Path::new(".")) {
Rc::new(loader)
} else {
Rc::new(IdleModuleLoader)
};
let job_queue = self
.job_queue
.unwrap_or_else(|| Rc::new(SimpleJobQueue::new()));
let mut context = Context {
interner: self.interner.unwrap_or_default(),
vm,
strict: false,
#[cfg(feature = "intl")]
intl_provider: if let Some(icu) = self.icu {
icu
} else {
cfg_if::cfg_if! {
if #[cfg(feature = "intl_bundled")] {
icu::IntlProvider::try_new_with_buffer_provider(boa_icu_provider::buffer())
.expect("Failed to initialize default icu data.")
} else {
return Err(JsNativeError::typ()
.with_message("missing Intl provider for context")
.into()
);
}
}
},
#[cfg(feature = "fuzz")]
instructions_remaining: self.instructions_remaining,
kept_alive: Vec::new(),
host_hooks,
job_queue,
module_loader,
optimizer_options: OptimizerOptions::OPTIMIZE_ALL,
root_shape,
parser_identifier: 0,
can_block: self.can_block,
};
builtins::set_default_global_bindings(&mut context)?;
Ok(context)
}
}
/// A cleanup guard for a [`Context`] that is executed when dropped.
#[derive(Debug)]
pub(crate) struct ContextCleanupGuard<'a, F>
where
F: FnOnce(&mut Context) + 'static,
{
context: &'a mut Context,
cleanup: Option<F>,
}
impl<'a, F> ContextCleanupGuard<'a, F>
where
F: FnOnce(&mut Context) + 'static,
{
/// Creates a new `ContextCleanupGuard` from the current context and its cleanup operation.
pub(crate) fn new(context: &'a mut Context, cleanup: F) -> Self {
Self {
context,
cleanup: Some(cleanup),
}
}
}
impl<F> std::ops::Deref for ContextCleanupGuard<'_, F>
where
F: FnOnce(&mut Context) + 'static,
{
type Target = Context;
fn deref(&self) -> &Self::Target {
self.context
}
}
impl<F> std::ops::DerefMut for ContextCleanupGuard<'_, F>
where
F: FnOnce(&mut Context) + 'static,
{
fn deref_mut(&mut self) -> &mut Self::Target {
self.context
}
}
impl<F> Drop for ContextCleanupGuard<'_, F>
where
F: FnOnce(&mut Context) + 'static,
{
fn drop(&mut self) {
if let Some(cleanup) = self.cleanup.take() {
cleanup(self.context);
}
}
}