Struct wasm_encoder::ElementSection

pub struct ElementSection { /* private fields */ }

An encoder for the element section.

Element sections are only supported for modules.

Example

use wasm_encoder::{
    Elements, ElementSection, Instruction, Module, TableSection, TableType,
    ValType,
};

let mut tables = TableSection::new();
tables.table(TableType {
    element_type: ValType::FuncRef,
    minimum: 128,
    maximum: None,
});

let mut elements = ElementSection::new();
let table_index = 0;
let offset = Instruction::I32Const(42);
let element_type = ValType::FuncRef;
let functions = Elements::Functions(&[
    // Function indices...
]);
elements.active(Some(table_index), &offset, element_type, functions);

let mut module = Module::new();
module
    .section(&tables)
    .section(&elements);

let wasm_bytes = module.finish();

Implementations

impl ElementSection

pub fn new() -> Self

Create a new element section encoder.

pub fn len(&self) -> u32

The number of element segments in the section.

pub fn is_empty(&self) -> bool

Determines if the section is empty.

pub fn segment<'a>(&mut self, segment: ElementSegment<'a>) -> &mut Self

Define an element segment.

pub fn active(
    &mut self,
    table_index: Option<u32>,
    offset: &Instruction<'_>,
    element_type: ValType,
    elements: Elements<'_>
) -> &mut Self

Define an active element segment.

Active element specifying a None table forces the MVP encoding and refers to the 0th table holding funcrefs. Non-None tables use the encoding introduced with the bulk memory proposal and can refer to tables with any valid reference type.

pub fn passive<'a>(
    &mut self,
    element_type: ValType,
    elements: Elements<'a>
) -> &mut Self

Encode a passive element segment.

Passive segments are part of the bulk memory proposal.

pub fn declared<'a>(
    &mut self,
    element_type: ValType,
    elements: Elements<'a>
) -> &mut Self

Encode a declared element segment.

Declared segments are part of the bulk memory proposal.

pub fn raw(&mut self, raw_bytes: &[u8]) -> &mut Self

Copy a raw, already-encoded element segment into this elements section.

Trait Implementations

impl Clone for ElementSection

fn clone(&self) -> ElementSection

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for ElementSection

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

Formats the value using the given formatter.

impl Default for ElementSection

fn default() -> ElementSection

Returns the “default value” for a type.

impl Section for ElementSection

fn id(&self) -> u8

Gets the section’s identifier.

fn encode<S>(&self, sink: &mut S) where
    S: Extend<u8>, 

Write this section’s header and data into the given sink.