Struct Buffer

pub struct Buffer { /* private fields */ }

Implementations

impl Buffer

pub fn from_uint8_array(array: &Uint8Array) -> Buffer

Methods from Deref<Target = Uint8Array>

pub fn fill(&self, value: u8, start: u32, end: u32) -> Uint8Array

The fill() method fills all the elements of an array from a start index to an end index with a static value. The end index is not included.

MDN documentation

pub fn buffer(&self) -> ArrayBuffer

The buffer accessor property represents the ArrayBuffer referenced by a TypedArray at construction time.

pub fn subarray(&self, begin: u32, end: u32) -> Uint8Array

The subarray() method returns a new TypedArray on the same ArrayBuffer store and with the same element types as for this TypedArray object.

pub fn slice(&self, begin: u32, end: u32) -> Uint8Array

The slice() method returns a shallow copy of a portion of a typed array into a new typed array object. This method has the same algorithm as Array.prototype.slice().

pub fn for_each(&self, callback: &mut dyn FnMut(u8, u32, Uint8Array))

The forEach() method executes a provided function once per array element. This method has the same algorithm as Array.prototype.forEach(). TypedArray is one of the typed array types here.

pub fn length(&self) -> u32

The length accessor property represents the length (in elements) of a typed array.

pub fn byte_length(&self) -> u32

The byteLength accessor property represents the length (in bytes) of a typed array.

pub fn byte_offset(&self) -> u32

The byteOffset accessor property represents the offset (in bytes) of a typed array from the start of its ArrayBuffer.

pub fn set(&self, src: &JsValue, offset: u32)

The set() method stores multiple values in the typed array, reading input values from a specified array.

pub fn at(&self, idx: i32) -> Option<u8>

Gets the value at idx, counting from the end if negative.

pub fn copy_within(&self, target: i32, start: i32, end: i32) -> Uint8Array

The copyWithin() method shallow copies part of a typed array to another location in the same typed array and returns it, without modifying its size.

MDN documentation

pub fn get_index(&self, idx: u32) -> u8

Gets the value at idx, equivalent to the javascript my_var = arr[idx].

pub fn set_index(&self, idx: u32, value: u8)

Sets the value at idx, equivalent to the javascript arr[idx] = value.

pub unsafe fn raw_copy_to_ptr(&self, dst: *mut u8)

Copy the contents of this JS typed array into the destination Rust pointer.

This function will efficiently copy the memory from a typed array into this Wasm module’s own linear memory, initializing the memory destination provided.

Safety

This function requires dst to point to a buffer large enough to fit this array’s contents.

pub fn copy_to(&self, dst: &mut [u8])

Copy the contents of this JS typed array into the destination Rust slice.

This function will efficiently copy the memory from a typed array into this Wasm module’s own linear memory, initializing the memory destination provided.

Panics

This function will panic if this typed array’s length is different than the length of the provided dst array.

pub fn copy_to_uninit<'dst>( &self, dst: &'dst mut [MaybeUninit<u8>], ) -> &'dst mut [u8]

Copy the contents of this JS typed array into the destination Rust slice.

This function will efficiently copy the memory from a typed array into this Wasm module’s own linear memory, initializing the memory destination provided.

Panics

This function will panic if this typed array’s length is different than the length of the provided dst array.

pub fn copy_from(&self, src: &[u8])

Copy the contents of the source Rust slice into this JS typed array.

This function will efficiently copy the memory from within the Wasm module’s own linear memory to this typed array.

Panics

This function will panic if this typed array’s length is different than the length of the provided src array.

pub fn to_vec(&self) -> Vec<u8>

Efficiently copies the contents of this JS typed array into a new Vec.

Methods from Deref<Target = Object>

pub fn constructor(&self) -> Function

The constructor property returns a reference to the Object constructor function that created the instance object.

MDN documentation

pub fn has_own_property(&self, property: &JsValue) -> bool

The hasOwnProperty() method returns a boolean indicating whether the object has the specified property as its own property (as opposed to inheriting it).

MDN documentation

pub fn is_prototype_of(&self, value: &JsValue) -> bool

The isPrototypeOf() method checks if an object exists in another object’s prototype chain.

MDN documentation

pub fn property_is_enumerable(&self, property: &JsValue) -> bool

The propertyIsEnumerable() method returns a Boolean indicating whether the specified property is enumerable.

MDN documentation

pub fn to_locale_string(&self) -> JsString

The toLocaleString() method returns a string representing the object. This method is meant to be overridden by derived objects for locale-specific purposes.

MDN documentation

pub fn to_string(&self) -> JsString

The toString() method returns a string representing the object.

MDN documentation

pub fn value_of(&self) -> Object

The valueOf() method returns the primitive value of the specified object.

MDN documentation

Methods from Deref<Target = JsValue>

pub const NULL: JsValue

pub const UNDEFINED: JsValue

pub const TRUE: JsValue

pub const FALSE: JsValue

pub fn as_f64(&self) -> Option<f64>

Returns the f64 value of this JS value if it’s an instance of a number.

If this JS value is not an instance of a number then this returns None.

pub fn is_string(&self) -> bool

Tests whether this JS value is a JS string.

pub fn as_string(&self) -> Option<String>

If this JS value is a string value, this function copies the JS string value into Wasm linear memory, encoded as UTF-8, and returns it as a Rust String.

To avoid the copying and re-encoding, consider the JsString::try_from() function from js-sys instead.

If this JS value is not an instance of a string or if it’s not valid utf-8 then this returns None.

UTF-16 vs UTF-8

JavaScript strings in general are encoded as UTF-16, but Rust strings are encoded as UTF-8. This can cause the Rust string to look a bit different than the JS string sometimes. For more details see the documentation about the str type which contains a few caveats about the encodings.

pub fn as_bool(&self) -> Option<bool>

Returns the bool value of this JS value if it’s an instance of a boolean.

If this JS value is not an instance of a boolean then this returns None.

pub fn is_null(&self) -> bool

Tests whether this JS value is null

pub fn is_undefined(&self) -> bool

Tests whether this JS value is undefined

pub fn is_symbol(&self) -> bool

Tests whether the type of this JS value is symbol

pub fn is_object(&self) -> bool

Tests whether typeof self == "object" && self !== null.

pub fn is_array(&self) -> bool

Tests whether this JS value is an instance of Array.

pub fn is_function(&self) -> bool

Tests whether the type of this JS value is function.

pub fn is_bigint(&self) -> bool

Tests whether the type of this JS value is bigint.

pub fn js_typeof(&self) -> JsValue

Applies the unary typeof JS operator on a JsValue.

MDN documentation

pub fn js_in(&self, obj: &JsValue) -> bool

Applies the binary in JS operator on the two JsValues.

MDN documentation

pub fn is_truthy(&self) -> bool

Tests whether the value is “truthy”.

pub fn is_falsy(&self) -> bool

Tests whether the value is “falsy”.

pub fn loose_eq(&self, other: &JsValue) -> bool

Compare two JsValues for equality, using the == operator in JS.

MDN documentation

pub fn bit_not(&self) -> JsValue

Applies the unary ~ JS operator on a JsValue.

MDN documentation

pub fn unsigned_shr(&self, rhs: &JsValue) -> u32

Applies the binary >>> JS operator on the two JsValues.

MDN documentation

pub fn checked_div(&self, rhs: &JsValue) -> JsValue

Applies the binary / JS operator on two JsValues, catching and returning any RangeError thrown.

MDN documentation

pub fn pow(&self, rhs: &JsValue) -> JsValue

Applies the binary ** JS operator on the two JsValues.

MDN documentation

pub fn lt(&self, other: &JsValue) -> bool

Applies the binary < JS operator on the two JsValues.

MDN documentation

pub fn le(&self, other: &JsValue) -> bool

Applies the binary <= JS operator on the two JsValues.

MDN documentation

pub fn ge(&self, other: &JsValue) -> bool

Applies the binary >= JS operator on the two JsValues.

MDN documentation

pub fn gt(&self, other: &JsValue) -> bool

Applies the binary > JS operator on the two JsValues.

MDN documentation

pub fn unchecked_into_f64(&self) -> f64

Applies the unary + JS operator on a JsValue. Can throw.

MDN documentation

Trait Implementations

impl AsRef<Buffer> for Buffer

fn as_ref(&self) -> &Buffer

Converts this type into a shared reference of the (usually inferred) input type.

impl AsRef<JsValue> for Buffer

fn as_ref(&self) -> &JsValue

Converts this type into a shared reference of the (usually inferred) input type.

impl AsRef<Uint8Array> for Buffer

fn as_ref(&self) -> &Uint8Array

Converts this type into a shared reference of the (usually inferred) input type.

impl Clone for Buffer

fn clone(&self) -> Buffer

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Buffer

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

Formats the value using the given formatter.

impl Deref for Buffer

type Target = Uint8Array

The resulting type after dereferencing.

fn deref(&self) -> &Uint8Array

Dereferences the value.

impl From<Buffer> for JsValue

fn from(obj: Buffer) -> JsValue

Converts to this type from the input type.

impl From<Buffer> for Uint8Array

fn from(obj: Buffer) -> Uint8Array

Converts to this type from the input type.

impl From<JsValue> for Buffer

fn from(obj: JsValue) -> Buffer

Converts to this type from the input type.

impl FromWasmAbi for Buffer

type Abi = <JsValue as FromWasmAbi>::Abi

The Wasm ABI type that this converts from when coming back out from the ABI boundary.

unsafe fn from_abi(js: Self::Abi) -> Self

Recover a Self from Self::Abi.

impl<'a> IntoWasmAbi for &'a Buffer

type Abi = <&'a JsValue as IntoWasmAbi>::Abi

The Wasm ABI type that this converts into when crossing the ABI boundary.

fn into_abi(self) -> Self::Abi

Convert self into Self::Abi so that it can be sent across the wasm ABI boundary.

impl IntoWasmAbi for Buffer

type Abi = <JsValue as IntoWasmAbi>::Abi

The Wasm ABI type that this converts into when crossing the ABI boundary.

fn into_abi(self) -> Self::Abi

Convert self into Self::Abi so that it can be sent across the wasm ABI boundary.

impl JsCast for Buffer

fn instanceof(val: &JsValue) -> bool

Performs a dynamic instanceof check to see whether the JsValue provided is an instance of this type.

fn unchecked_from_js(val: JsValue) -> Self

Performs a zero-cost unchecked conversion from a JsValue into an instance of Self

fn unchecked_from_js_ref(val: &JsValue) -> &Self

Performs a zero-cost unchecked conversion from a &JsValue into an instance of &Self.

fn has_type<T>(&self) -> bool

where T: JsCast,

Test whether this JS value has a type T.

fn dyn_into<T>(self) -> Result<T, Self>

where T: JsCast,

Performs a dynamic cast (checked at runtime) of this value into the target type T.

fn dyn_ref<T>(&self) -> Option<&T>

where T: JsCast,

Performs a dynamic cast (checked at runtime) of this value into the target type T.

fn unchecked_into<T>(self) -> T

where T: JsCast,

Performs a zero-cost unchecked cast into the specified type.

fn unchecked_ref<T>(&self) -> &T

where T: JsCast,

Performs a zero-cost unchecked cast into a reference to the specified type.

fn is_instance_of<T>(&self) -> bool

where T: JsCast,

Test whether this JS value is an instance of the type T.

fn is_type_of(val: &JsValue) -> bool

Performs a dynamic check to see whether the JsValue provided is a value of this type.

impl LongRefFromWasmAbi for Buffer

type Abi = <JsValue as LongRefFromWasmAbi>::Abi

Same as RefFromWasmAbi::Abi

type Anchor = Buffer

Same as RefFromWasmAbi::Anchor

unsafe fn long_ref_from_abi(js: Self::Abi) -> Self::Anchor

Same as RefFromWasmAbi::ref_from_abi

impl OptionFromWasmAbi for Buffer

fn is_none(abi: &Self::Abi) -> bool

Tests whether the argument is a “none” instance. If so it will be deserialized as None, and otherwise it will be passed to FromWasmAbi.

impl<'a> OptionIntoWasmAbi for &'a Buffer

fn none() -> Self::Abi

Returns an ABI instance indicating “none”, which JS will interpret as the None branch of this option.

impl OptionIntoWasmAbi for Buffer

fn none() -> Self::Abi

Returns an ABI instance indicating “none”, which JS will interpret as the None branch of this option.

impl RefFromWasmAbi for Buffer

type Abi = <JsValue as RefFromWasmAbi>::Abi

The Wasm ABI type references to Self are recovered from.

type Anchor = ManuallyDrop<Buffer>

The type that holds the reference to Self for the duration of the invocation of the function that has an &Self parameter. This is required to ensure that the lifetimes don’t persist beyond one function call, and so that they remain anonymous.

unsafe fn ref_from_abi(js: Self::Abi) -> Self::Anchor

Recover a Self::Anchor from Self::Abi.

impl WasmDescribe for Buffer

fn describe()