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use super::{COMPONENT_SORT, CORE_MODULE_SORT, CORE_SORT, CORE_TYPE_SORT, TYPE_SORT};
use crate::{
encode_section, ComponentExportKind, ComponentSection, ComponentSectionId, Encode, ExportKind,
};
/// Represents the kinds of outer aliasable items in a component.
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub enum ComponentOuterAliasKind {
/// The alias is to a core module.
CoreModule,
/// The alias is to a core type.
CoreType,
/// The alias is to a type.
Type,
/// The alias is to a component.
Component,
}
impl Encode for ComponentOuterAliasKind {
fn encode(&self, sink: &mut Vec<u8>) {
match self {
Self::CoreModule => {
sink.push(CORE_SORT);
sink.push(CORE_MODULE_SORT);
}
Self::CoreType => {
sink.push(CORE_SORT);
sink.push(CORE_TYPE_SORT);
}
Self::Type => sink.push(TYPE_SORT),
Self::Component => sink.push(COMPONENT_SORT),
}
}
}
/// An encoder for the alias section of WebAssembly component.
///
/// # Example
///
/// ```rust
/// use wasm_encoder::{Component, ComponentAliasSection, ComponentExportKind, ComponentOuterAliasKind};
///
/// let mut aliases = ComponentAliasSection::new();
/// aliases.instance_export(0, ComponentExportKind::Func, "f");
/// aliases.outer(0, ComponentOuterAliasKind::Type, 1);
///
/// let mut component = Component::new();
/// component.section(&aliases);
///
/// let bytes = component.finish();
/// ```
#[derive(Clone, Debug, Default)]
pub struct ComponentAliasSection {
bytes: Vec<u8>,
num_added: u32,
}
impl ComponentAliasSection {
/// Create a new alias section encoder.
pub fn new() -> Self {
Self::default()
}
/// The number of aliases in the section.
pub fn len(&self) -> u32 {
self.num_added
}
/// Determines if the section is empty.
pub fn is_empty(&self) -> bool {
self.num_added == 0
}
/// Define an alias to a component instance's export.
pub fn instance_export(
&mut self,
instance_index: u32,
kind: ComponentExportKind,
name: &str,
) -> &mut Self {
kind.encode(&mut self.bytes);
self.bytes.push(0x00);
instance_index.encode(&mut self.bytes);
name.encode(&mut self.bytes);
self.num_added += 1;
self
}
/// Define an alias to a core instance's export.
pub fn core_instance_export(
&mut self,
instance_index: u32,
kind: ExportKind,
name: &str,
) -> &mut Self {
self.bytes.push(CORE_SORT);
kind.encode(&mut self.bytes);
self.bytes.push(0x01);
instance_index.encode(&mut self.bytes);
name.encode(&mut self.bytes);
self.num_added += 1;
self
}
/// Define an alias to an outer component item.
///
/// The count starts at 0 to indicate the current component, 1 indicates the direct
/// parent, 2 the grandparent, etc.
pub fn outer(&mut self, count: u32, kind: ComponentOuterAliasKind, index: u32) -> &mut Self {
kind.encode(&mut self.bytes);
self.bytes.push(0x02);
count.encode(&mut self.bytes);
index.encode(&mut self.bytes);
self.num_added += 1;
self
}
}
impl Encode for ComponentAliasSection {
fn encode(&self, sink: &mut Vec<u8>) {
encode_section(sink, self.num_added, &self.bytes);
}
}
impl ComponentSection for ComponentAliasSection {
fn id(&self) -> u8 {
ComponentSectionId::Alias.into()
}
}
|
