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- Separate builtin function from rust JavaScript function - Removed BuiltInFunction structpull/1612/head
Halid Odat
3 years ago
committed by
GitHub
23 changed files with 1446 additions and 713 deletions
@ -0,0 +1,376 @@
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//! This module implements the global `Function` object as well as creates Native Functions.
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//!
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//! Objects wrap `Function`s and expose them via call/construct slots.
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//!
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//! `The `Function` object is used for matching text with a pattern.
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//!
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//! More information:
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//! - [ECMAScript reference][spec]
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//! - [MDN documentation][mdn]
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//!
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//! [spec]: https://tc39.es/ecma262/#sec-function-objects
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//! [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function
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use crate::{ |
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environment::lexical_environment::Environment, |
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gc::{Finalize, Trace}, |
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object::{JsObject, Object}, |
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property::PropertyDescriptor, |
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syntax::ast::node::{FormalParameter, RcStatementList}, |
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BoaProfiler, Context, JsResult, JsValue, |
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}; |
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use dyn_clone::DynClone; |
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use std::{ |
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fmt, |
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ops::{Deref, DerefMut}, |
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}; |
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use super::NativeObject; |
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/// Type representing a native built-in function a.k.a. function pointer.
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///
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/// Native functions need to have this signature in order to
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/// be callable from Javascript.
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pub type NativeFunctionSignature = fn(&JsValue, &[JsValue], &mut Context) -> JsResult<JsValue>; |
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// Allows restricting closures to only `Copy` ones.
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// Used the sealed pattern to disallow external implementations
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// of `DynCopy`.
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mod sealed { |
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pub trait Sealed {} |
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impl<T: Copy> Sealed for T {} |
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} |
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pub trait DynCopy: sealed::Sealed {} |
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impl<T: Copy> DynCopy for T {} |
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/// Trait representing a native built-in closure.
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///
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/// Closures need to have this signature in order to
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/// be callable from Javascript, but most of the time the compiler
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/// is smart enough to correctly infer the types.
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pub trait ClosureFunctionSignature: |
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Fn(&JsValue, &[JsValue], Captures, &mut Context) -> JsResult<JsValue> + DynCopy + DynClone + 'static |
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{ |
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} |
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// The `Copy` bound automatically infers `DynCopy` and `DynClone`
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impl<T> ClosureFunctionSignature for T where |
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T: Fn(&JsValue, &[JsValue], Captures, &mut Context) -> JsResult<JsValue> + Copy + 'static |
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{ |
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} |
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// Allows cloning Box<dyn ClosureFunctionSignature>
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dyn_clone::clone_trait_object!(ClosureFunctionSignature); |
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#[derive(Debug, Trace, Finalize, PartialEq, Clone)] |
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pub enum ThisMode { |
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Lexical, |
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Strict, |
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Global, |
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} |
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impl ThisMode { |
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/// Returns `true` if the this mode is `Lexical`.
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pub fn is_lexical(&self) -> bool { |
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matches!(self, Self::Lexical) |
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} |
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/// Returns `true` if the this mode is `Strict`.
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pub fn is_strict(&self) -> bool { |
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matches!(self, Self::Strict) |
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} |
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/// Returns `true` if the this mode is `Global`.
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pub fn is_global(&self) -> bool { |
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matches!(self, Self::Global) |
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} |
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} |
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#[derive(Debug, Trace, Finalize, PartialEq, Clone)] |
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pub enum ConstructorKind { |
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Base, |
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Derived, |
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} |
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impl ConstructorKind { |
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/// Returns `true` if the constructor kind is `Base`.
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pub fn is_base(&self) -> bool { |
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matches!(self, Self::Base) |
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} |
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/// Returns `true` if the constructor kind is `Derived`.
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pub fn is_derived(&self) -> bool { |
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matches!(self, Self::Derived) |
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} |
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} |
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// We don't use a standalone `NativeObject` for `Captures` because it doesn't
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// guarantee that the internal type implements `Clone`.
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// This private trait guarantees that the internal type passed to `Captures`
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// implements `Clone`, and `DynClone` allows us to implement `Clone` for
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// `Box<dyn CapturesObject>`.
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trait CapturesObject: NativeObject + DynClone {} |
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impl<T: NativeObject + Clone> CapturesObject for T {} |
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dyn_clone::clone_trait_object!(CapturesObject); |
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/// Wrapper for `Box<dyn NativeObject + Clone>` that allows passing additional
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/// captures through a `Copy` closure.
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///
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/// Any type implementing `Trace + Any + Debug + Clone`
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/// can be used as a capture context, so you can pass e.g. a String,
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/// a tuple or even a full struct.
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///
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/// You can downcast to any type and handle the fail case as you like
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/// with `downcast_ref` and `downcast_mut`, or you can use `try_downcast_ref`
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/// and `try_downcast_mut` to automatically throw a `TypeError` if the downcast
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/// fails.
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#[derive(Debug, Clone, Trace, Finalize)] |
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pub struct Captures(Box<dyn CapturesObject>); |
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impl Captures { |
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/// Creates a new capture context.
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pub(crate) fn new<T>(captures: T) -> Self |
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where |
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T: NativeObject + Clone, |
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{ |
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Self(Box::new(captures)) |
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} |
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/// Downcasts `Captures` to the specified type, returning a reference to the
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/// downcasted type if successful or `None` otherwise.
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pub fn downcast_ref<T>(&self) -> Option<&T> |
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where |
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T: NativeObject + Clone, |
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{ |
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self.0.deref().as_any().downcast_ref::<T>() |
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} |
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/// Mutably downcasts `Captures` to the specified type, returning a
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/// mutable reference to the downcasted type if successful or `None` otherwise.
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pub fn downcast_mut<T>(&mut self) -> Option<&mut T> |
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where |
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T: NativeObject + Clone, |
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{ |
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self.0.deref_mut().as_mut_any().downcast_mut::<T>() |
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} |
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/// Downcasts `Captures` to the specified type, returning a reference to the
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/// downcasted type if successful or a `TypeError` otherwise.
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pub fn try_downcast_ref<T>(&self, context: &mut Context) -> JsResult<&T> |
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where |
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T: NativeObject + Clone, |
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{ |
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self.0 |
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.deref() |
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.as_any() |
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.downcast_ref::<T>() |
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.ok_or_else(|| context.construct_type_error("cannot downcast `Captures` to given type")) |
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} |
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/// Downcasts `Captures` to the specified type, returning a reference to the
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/// downcasted type if successful or a `TypeError` otherwise.
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pub fn try_downcast_mut<T>(&mut self, context: &mut Context) -> JsResult<&mut T> |
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where |
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T: NativeObject + Clone, |
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{ |
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self.0 |
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.deref_mut() |
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.as_mut_any() |
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.downcast_mut::<T>() |
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.ok_or_else(|| context.construct_type_error("cannot downcast `Captures` to given type")) |
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} |
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} |
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/// Boa representation of a Function Object.
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///
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/// FunctionBody is specific to this interpreter, it will either be Rust code or JavaScript code (AST Node)
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///
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/// <https://tc39.es/ecma262/#sec-ecmascript-function-objects>
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#[derive(Clone, Trace, Finalize)] |
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pub enum Function { |
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Native { |
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#[unsafe_ignore_trace] |
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function: NativeFunctionSignature, |
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constructable: bool, |
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}, |
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Closure { |
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#[unsafe_ignore_trace] |
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function: Box<dyn ClosureFunctionSignature>, |
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constructable: bool, |
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captures: Captures, |
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}, |
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Ordinary { |
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constructable: bool, |
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this_mode: ThisMode, |
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body: RcStatementList, |
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params: Box<[FormalParameter]>, |
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environment: Environment, |
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}, |
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#[cfg(feature = "vm")] |
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VmOrdinary { |
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code: gc::Gc<crate::vm::CodeBlock>, |
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environment: Environment, |
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}, |
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} |
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impl fmt::Debug for Function { |
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fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
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write!(f, "Function {{ ... }}") |
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} |
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} |
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impl Function { |
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// Adds the final rest parameters to the Environment as an array
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#[cfg(not(feature = "vm"))] |
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pub(crate) fn add_rest_param( |
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param: &FormalParameter, |
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index: usize, |
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args_list: &[JsValue], |
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context: &mut Context, |
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local_env: &Environment, |
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) { |
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use crate::builtins::Array; |
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// Create array of values
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let array = Array::new_array(context); |
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Array::add_to_array_object(&array, args_list.get(index..).unwrap_or_default(), context) |
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.unwrap(); |
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// Create binding
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local_env |
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// Function parameters can share names in JavaScript...
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.create_mutable_binding(param.name(), false, true, context) |
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.expect("Failed to create binding for rest param"); |
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// Set Binding to value
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local_env |
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.initialize_binding(param.name(), array, context) |
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.expect("Failed to initialize rest param"); |
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} |
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// Adds an argument to the environment
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pub(crate) fn add_arguments_to_environment( |
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param: &FormalParameter, |
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value: JsValue, |
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local_env: &Environment, |
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context: &mut Context, |
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) { |
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// Create binding
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local_env |
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.create_mutable_binding(param.name(), false, true, context) |
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.expect("Failed to create binding"); |
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// Set Binding to value
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local_env |
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.initialize_binding(param.name(), value, context) |
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.expect("Failed to intialize binding"); |
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} |
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/// Returns true if the function object is constructable.
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pub fn is_constructable(&self) -> bool { |
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match self { |
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Self::Native { constructable, .. } => *constructable, |
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Self::Closure { constructable, .. } => *constructable, |
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Self::Ordinary { constructable, .. } => *constructable, |
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#[cfg(feature = "vm")] |
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Self::VmOrdinary { code, .. } => code.constructable, |
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} |
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} |
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} |
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/// Arguments.
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///
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/// <https://tc39.es/ecma262/#sec-createunmappedargumentsobject>
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pub fn create_unmapped_arguments_object( |
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arguments_list: &[JsValue], |
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context: &mut Context, |
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) -> JsResult<JsValue> { |
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let len = arguments_list.len(); |
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let obj = JsObject::new(Object::default()); |
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// Set length
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let length = PropertyDescriptor::builder() |
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.value(len) |
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.writable(true) |
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.enumerable(false) |
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.configurable(true) |
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.build(); |
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// Define length as a property
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crate::object::internal_methods::ordinary_define_own_property( |
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&obj, |
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"length".into(), |
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length, |
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context, |
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)?; |
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let mut index: usize = 0; |
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while index < len { |
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let val = arguments_list.get(index).expect("Could not get argument"); |
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let prop = PropertyDescriptor::builder() |
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.value(val.clone()) |
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.writable(true) |
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.enumerable(true) |
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.configurable(true); |
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obj.insert(index, prop); |
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index += 1; |
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} |
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Ok(JsValue::new(obj)) |
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} |
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/// Creates a new member function of a `Object` or `prototype`.
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///
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/// A function registered using this macro can then be called from Javascript using:
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///
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/// parent.name()
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///
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/// See the javascript 'Number.toString()' as an example.
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///
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/// # Arguments
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/// function: The function to register as a built in function.
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/// name: The name of the function (how it will be called but without the ()).
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/// parent: The object to register the function on, if the global object is used then the function is instead called as name()
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/// without requiring the parent, see parseInt() as an example.
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/// length: As described at <https://tc39.es/ecma262/#sec-function-instances-length>, The value of the "length" property is an integer that
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/// indicates the typical number of arguments expected by the function. However, the language permits the function to be invoked with
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/// some other number of arguments.
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///
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/// If no length is provided, the length will be set to 0.
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// TODO: deprecate/remove this.
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pub(crate) fn make_builtin_fn<N>( |
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function: NativeFunctionSignature, |
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name: N, |
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parent: &JsObject, |
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length: usize, |
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interpreter: &Context, |
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) where |
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N: Into<String>, |
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{ |
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let name = name.into(); |
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let _timer = BoaProfiler::global().start_event(&format!("make_builtin_fn: {}", &name), "init"); |
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let mut function = Object::function( |
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Function::Native { |
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function, |
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constructable: false, |
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}, |
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interpreter |
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.standard_objects() |
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.function_object() |
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.prototype() |
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.into(), |
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); |
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let attribute = PropertyDescriptor::builder() |
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.writable(false) |
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.enumerable(false) |
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.configurable(true); |
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function.insert_property("length", attribute.clone().value(length)); |
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function.insert_property("name", attribute.value(name.as_str())); |
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parent.clone().insert_property( |
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name, |
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PropertyDescriptor::builder() |
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.value(function) |
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.writable(true) |
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.enumerable(false) |
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.configurable(true), |
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); |
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} |
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