Struct boa_engine::object::builtins::JsArrayBuffer

pub struct JsArrayBuffer { /* private fields */ }

JsArrayBuffer provides a wrapper for Boa’s implementation of the ECMAScript ArrayBuffer object

Implementations

impl JsArrayBuffer

pub fn new(byte_length: usize, context: &mut Context) -> JsResult<Self>

Create a new array buffer with byte length.

// Creates a blank array buffer of n bytes
let array_buffer = JsArrayBuffer::new(4, context)?;

assert_eq!(array_buffer.detach(&JsValue::undefined())?, vec![0_u8; 4]);

pub fn from_byte_block( byte_block: Vec<u8>, context: &mut Context ) -> JsResult<Self>

Create a new array buffer from byte block.

This uses the passed byte block as the internal storage, it does not clone it!

The byte_length will be set to byte_block.len().

// Create a buffer from a chunk of data
let data_block: Vec<u8> = (0..5).collect();
let array_buffer = JsArrayBuffer::from_byte_block(data_block, context)?;

assert_eq!(
    array_buffer.detach(&JsValue::undefined())?,
    (0..5).collect::<Vec<u8>>()
);

pub fn from_object(object: JsObject) -> JsResult<Self>

Create a JsArrayBuffer from a JsObject, if the object is not an array buffer throw a TypeError.

This does not clone the fields of the array buffer, it only does a shallow clone of the object.

pub fn byte_length(&self) -> usize

Returns the byte length of the array buffer.

// Create a buffer from a chunk of data
let data_block: Vec<u8> = (0..5).collect();
let array_buffer = JsArrayBuffer::from_byte_block(data_block, context)?;

// Take the inner buffer
let buffer_length = array_buffer.byte_length();

assert_eq!(buffer_length, 5);

pub fn detach(&self, detach_key: &JsValue) -> JsResult<Vec<u8>>

Take the inner ArrayBuffer’s array_buffer_data field and replace it with None

Note

This tries to detach the pre-existing JsArrayBuffer, meaning the original detach key is required. By default, the key is set to undefined.

// Create a buffer from a chunk of data
let data_block: Vec<u8> = (0..5).collect();
let array_buffer = JsArrayBuffer::from_byte_block(data_block, context)?;

// Take the inner buffer
let internal_buffer = array_buffer.detach(&JsValue::undefined())?;

assert_eq!(internal_buffer, (0..5).collect::<Vec<u8>>());

// Anymore interaction with the buffer will return an error
let detached_err = array_buffer.detach(&JsValue::undefined());
assert!(detached_err.is_err());

pub fn data(&self) -> Option<GcRef<'_, [u8]>>

Get an immutable reference to the JsArrayBuffer’s data.

Returns None if detached.

// Create a buffer from a chunk of data
let data_block: Vec<u8> = (0..5).collect();
let array_buffer = JsArrayBuffer::from_byte_block(data_block, context)?;

// Get a reference to the data.
let internal_buffer = array_buffer.data();

assert_eq!(
    internal_buffer.as_deref(),
    Some((0..5).collect::<Vec<u8>>().as_slice())
);

pub fn data_mut(&self) -> Option<GcRefMut<'_, Object<ArrayBuffer>, [u8]>>

Get a mutable reference to the JsArrayBuffer’s data.

Returns None if detached.

// Create a buffer from a chunk of data
let data_block: Vec<u8> = (0..5).collect();
let array_buffer = JsArrayBuffer::from_byte_block(data_block, context)?;

// Get a reference to the data.
let mut internal_buffer = array_buffer
    .data_mut()
    .expect("the buffer should not be detached");

internal_buffer.fill(10);

assert_eq!(&*internal_buffer, vec![10u8; 5].as_slice());

Methods from Deref<Target = JsObject<ArrayBuffer>>

pub fn downcast_ref<T: NativeObject>(&self) -> Option<Ref<'_, T>>

Downcasts a reference to the object, if the object is of type T.

Panics

Panics if the object is currently mutably borrowed.

pub fn downcast_mut<T: NativeObject>( &self ) -> Option<RefMut<'_, ErasedObject, T>>

Downcasts a mutable reference to the object, if the object is type native object type T.

Panics

Panics if the object is currently borrowed.

pub fn is<T: NativeObject>(&self) -> bool

Checks if this object is an instance of a certain NativeObject.

Panics

Panics if the object is currently mutably borrowed.

pub fn is_ordinary(&self) -> bool

Checks if it’s an ordinary object.

Panics

Panics if the object is currently mutably borrowed.

pub fn is_array(&self) -> bool

Checks if it’s an Array object.

pub fn to_property_descriptor( &self, context: &mut Context ) -> JsResult<PropertyDescriptor>

The abstract operation ToPropertyDescriptor.

More information:

• ECMAScript reference

pub fn copy_data_properties<K>( &self, source: &JsValue, excluded_keys: Vec<K>, context: &mut Context ) -> JsResult<()>

where K: Into<PropertyKey>,

7.3.25 CopyDataProperties ( target, source, excludedItems )

More information:

• ECMAScript

pub fn borrow(&self) -> Ref<'_, Object<T>>

Immutably borrows the Object.

The borrow lasts until the returned Ref exits scope. Multiple immutable borrows can be taken out at the same time.

Panics

Panics if the object is currently mutably borrowed.

pub fn borrow_mut(&self) -> RefMut<'_, Object<T>, Object<T>>

Mutably borrows the Object.

The borrow lasts until the returned RefMut exits scope. The object cannot be borrowed while this borrow is active.

Panics

Panics if the object is currently borrowed.

pub fn try_borrow(&self) -> StdResult<Ref<'_, Object<T>>, BorrowError>

Immutably borrows the Object, returning an error if the value is currently mutably borrowed.

The borrow lasts until the returned GcCellRef exits scope. Multiple immutable borrows can be taken out at the same time.

This is the non-panicking variant of borrow.

pub fn try_borrow_mut( &self ) -> StdResult<RefMut<'_, Object<T>, Object<T>>, BorrowMutError>

Mutably borrows the object, returning an error if the value is currently borrowed.

The borrow lasts until the returned GcCellRefMut exits scope. The object be borrowed while this borrow is active.

This is the non-panicking variant of borrow_mut.

pub fn prototype(&self) -> JsPrototype

Get the prototype of the object.

Panics

Panics if the object is currently mutably borrowed.

pub fn set_prototype(&self, prototype: JsPrototype) -> bool

Set the prototype of the object.

Panics

Panics if the object is currently mutably borrowed

pub fn insert_property<K, P>(&self, key: K, property: P) -> bool

where K: Into<PropertyKey>, P: Into<PropertyDescriptor>,

Inserts a field in the object properties without checking if it’s writable.

If a field was already in the object with the same name, than true is returned with that field, otherwise false is returned.

pub fn is_callable(&self) -> bool

It determines if Object is a callable function with a [[Call]] internal method.

More information:

• ECMAScript reference

pub fn is_constructor(&self) -> bool

It determines if Object is a function object with a [[Construct]] internal method.

More information:

• ECMAScript reference

pub fn is_extensible(&self, context: &mut Context) -> JsResult<bool>

Check if object is extensible.

More information:

• ECMAScript reference

pub fn get<K>(&self, key: K, context: &mut Context) -> JsResult<JsValue>

where K: Into<PropertyKey>,

Get property from object or throw.

More information:

• ECMAScript reference

pub fn set<K, V>( &self, key: K, value: V, throw: bool, context: &mut Context ) -> JsResult<bool>

where K: Into<PropertyKey>, V: Into<JsValue>,

set property of object or throw if bool flag is passed.

More information:

• ECMAScript reference

pub fn create_data_property<K, V>( &self, key: K, value: V, context: &mut Context ) -> JsResult<bool>

where K: Into<PropertyKey>, V: Into<JsValue>,

Create data property

More information:

• ECMAScript reference

pub fn create_data_property_or_throw<K, V>( &self, key: K, value: V, context: &mut Context ) -> JsResult<bool>

where K: Into<PropertyKey>, V: Into<JsValue>,

Create data property or throw

More information:

• ECMAScript reference

pub fn define_property_or_throw<K, P>( &self, key: K, desc: P, context: &mut Context ) -> JsResult<bool>

where K: Into<PropertyKey>, P: Into<PropertyDescriptor>,

Define property or throw.

More information:

• ECMAScript reference

pub fn delete_property_or_throw<K>( &self, key: K, context: &mut Context ) -> JsResult<bool>

where K: Into<PropertyKey>,

Defines the property or throws a TypeError if the operation fails.

More information:

• ECMAScript reference

pub fn has_property<K>(&self, key: K, context: &mut Context) -> JsResult<bool>

where K: Into<PropertyKey>,

Check if object has property.

More information:

• ECMAScript reference

pub fn has_own_property<K>( &self, key: K, context: &mut Context ) -> JsResult<bool>

where K: Into<PropertyKey>,

Check if object has an own property.

More information:

• ECMAScript reference

pub fn call( &self, this: &JsValue, args: &[JsValue], context: &mut Context ) -> JsResult<JsValue>

Call ( F, V [ , argumentsList ] )

Panics

Panics if the object is currently mutably borrowed.

More information:

• ECMAScript reference

pub fn construct( &self, args: &[JsValue], new_target: Option<&Self>, context: &mut Context ) -> JsResult<Self>

Construct ( F [ , argumentsList [ , newTarget ] ] )

Construct an instance of this object with the specified arguments.

Panics

Panics if the object is currently mutably borrowed.

More information:

• ECMAScript reference

pub fn set_integrity_level( &self, level: IntegrityLevel, context: &mut Context ) -> JsResult<bool>

Make the object sealed or frozen.

More information:

• ECMAScript reference

pub fn test_integrity_level( &self, level: IntegrityLevel, context: &mut Context ) -> JsResult<bool>

Check if the object is sealed or frozen.

More information:

• ECMAScript reference

Trait Implementations

impl Clone for JsArrayBuffer

fn clone(&self) -> JsArrayBuffer

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for JsArrayBuffer

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Deref for JsArrayBuffer

type Target = JsObject<ArrayBuffer>

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl Finalize for JsArrayBuffer

fn finalize(&self)

Cleanup logic for a type.

impl From<JsArrayBuffer> for JsObject

fn from(o: JsArrayBuffer) -> Self

Converts to this type from the input type.

impl From<JsArrayBuffer> for JsObject<ArrayBuffer>

fn from(value: JsArrayBuffer) -> Self

Converts to this type from the input type.

impl From<JsArrayBuffer> for JsValue

fn from(o: JsArrayBuffer) -> Self

Converts to this type from the input type.

impl From<JsObject<ArrayBuffer>> for JsArrayBuffer

fn from(value: JsObject<ArrayBuffer>) -> Self

Converts to this type from the input type.

impl Trace for JsArrayBuffer

unsafe fn trace(&self, tracer: &mut Tracer)

Marks all contained Gcs.

unsafe fn trace_non_roots(&self)

Trace handles located in GC heap, and mark them as non root.

fn run_finalizer(&self)

Runs Finalize::finalize on this object and all contained subobjects.

impl TryFromJs for JsArrayBuffer

fn try_from_js(value: &JsValue, _context: &mut Context) -> JsResult<Self>

This function tries to convert a JavaScript value into Self.