Struct neon::types::JsBuffer

pub struct JsBuffer(/* private fields */);

The type of Node Buffer objects.

Example

use neon::types::buffer::TypedArray;

fn make_sequence(mut cx: FunctionContext) -> JsResult<JsBuffer> {
    let len = cx.argument::<JsNumber>(0)?.value(&mut cx);
    let mut buffer = cx.buffer(len as usize)?;

    for (i, elem) in buffer.as_mut_slice(&mut cx).iter_mut().enumerate() {
        *elem = i as u8;
    }

    Ok(buffer)
}

Implementations

impl JsBuffer

pub fn new<'a, C: Context<'a>>(cx: &mut C, len: usize) -> JsResult<'a, Self>

Constructs a new Buffer object, safely zero-filled.

See also: Context::buffer

pub fn from_slice<'cx, C>(cx: &mut C, slice: &[u8]) -> JsResult<'cx, Self>

where C: Context<'cx>,

Constructs a JsBuffer from a slice by copying its contents.

This method is defined on JsBuffer as a convenience and delegates to TypedArray::from_slice.

pub unsafe fn uninitialized<'a, C: Context<'a>>( cx: &mut C, len: usize ) -> JsResult<'a, Self>

Constructs a new Buffer object with uninitialized memory

pub fn external<'a, C, T>(cx: &mut C, data: T) -> Handle<'a, Self>

where C: Context<'a>, T: AsMut<[u8]> + Send + 'static,

Available on crate feature external-buffers only.

Construct a new Buffer from bytes allocated by Rust.

Compatibility Note

Some Node environments are built using V8’s sandboxed pointers functionality, which disallows the use of external buffers. In those environments, calling the underlying runtime function used by this method results in an immediate termination of the Node VM.

As a result, this API is disabled by default. If you are confident that your code will only be used in environments that disable sandboxed pointers, you can make use of this method by enabling the external-buffers feature flag.

Trait Implementations

impl Debug for JsBuffer

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

Formats the value using the given formatter.

impl Object for JsBuffer

fn get_opt<'a, V: Value, C: Context<'a>, K: PropertyKey>( &self, cx: &mut C, key: K ) -> NeonResult<Option<Handle<'a, V>>>

Gets a property from a JavaScript object that may be undefined and attempts to downcast the value if it existed.

fn get_value<'a, C: Context<'a>, K: PropertyKey>( &self, cx: &mut C, key: K ) -> NeonResult<Handle<'a, JsValue>>

Gets a property from a JavaScript object as a JsValue.

fn get<'a, V: Value, C: Context<'a>, K: PropertyKey>( &self, cx: &mut C, key: K ) -> NeonResult<Handle<'a, V>>

Gets a property from a JavaScript object and attempts to downcast as a specific type. Equivalent to calling obj.get_value(&mut cx)?.downcast_or_throw(&mut cx).

fn get_own_property_names<'a, C: Context<'a>>( &self, cx: &mut C ) -> JsResult<'a, JsArray>

Available on crate feature napi-6 only.

fn freeze<'a, C: Context<'a>>(&self, cx: &mut C) -> NeonResult<&Self>

fn seal<'a, C: Context<'a>>(&self, cx: &mut C) -> NeonResult<&Self>

fn set<'a, C: Context<'a>, K: PropertyKey, W: Value>( &self, cx: &mut C, key: K, val: Handle<'_, W> ) -> NeonResult<bool>

fn root<'a, C: Context<'a>>(&self, cx: &mut C) -> Root<Self>

fn call_method_with<'a, C, K>( &self, cx: &mut C, method: K ) -> NeonResult<CallOptions<'a>>

where C: Context<'a>, K: PropertyKey,

impl TypedArray for JsBuffer

type Item = u8

fn as_slice<'cx, 'a, C>(&self, cx: &'a C) -> &'a [Self::Item]

where C: Context<'cx>,

Statically checked immutable borrow of binary data.

fn as_mut_slice<'cx, 'a, C>(&mut self, cx: &'a mut C) -> &'a mut [Self::Item]

where C: Context<'cx>,

Statically checked mutable borrow of binary data.

fn try_borrow<'cx, 'a, C>( &self, lock: &'a Lock<'_, C> ) -> Result<Ref<'a, Self::Item>, BorrowError>

where C: Context<'cx>,

Dynamically checked immutable borrow of binary data, returning an error if the the borrow would overlap with a mutable borrow.

fn try_borrow_mut<'cx, 'a, C>( &mut self, lock: &'a Lock<'_, C> ) -> Result<RefMut<'a, Self::Item>, BorrowError>

where C: Context<'cx>,

Dynamically checked mutable borrow of binary data, returning an error if the the borrow would overlap with an active borrow.

fn size<'cx, C: Context<'cx>>(&self, cx: &mut C) -> usize

Returns the size, in bytes, of the allocated binary data.

fn from_slice<'cx, C>(cx: &mut C, slice: &[u8]) -> JsResult<'cx, Self>

where C: Context<'cx>,

Constructs an instance from a slice by copying its contents.

impl Value for JsBuffer

fn to_string<'cx, C: Context<'cx>>(&self, cx: &mut C) -> JsResult<'cx, JsString>

fn as_value<'cx, C: Context<'cx>>(&self, _: &mut C) -> Handle<'cx, JsValue>

fn to_raw(&self) -> Value

Available on crate feature sys only.

Get a raw reference to the wrapped Node-API value.

unsafe fn from_raw<'cx, C: Context<'cx>>( cx: &C, value: Value ) -> Handle<'cx, Self>

Available on crate feature sys only.

Creates a value from a raw Node-API value.