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use super::CORE_INSTANCE_SORT;
use crate::{
encode_section, ComponentExportKind, ComponentSection, ComponentSectionId, Encode, ExportKind,
};
/// Represents an argument to a module instantiation.
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub enum ModuleArg {
/// The argument is an instance.
Instance(u32),
}
impl Encode for ModuleArg {
fn encode(&self, sink: &mut Vec<u8>) {
let (sort, idx) = match self {
Self::Instance(idx) => (CORE_INSTANCE_SORT, *idx),
};
sink.push(sort);
idx.encode(sink);
}
}
/// An encoder for the core instance section of WebAssembly components.
///
/// # Example
///
/// ```rust
/// use wasm_encoder::{Component, InstanceSection, ExportKind, ModuleArg};
///
/// let mut instances = InstanceSection::new();
/// instances.export_items([("foo", ExportKind::Func, 0)]);
/// instances.instantiate(1, [("foo", ModuleArg::Instance(0))]);
///
/// let mut component = Component::new();
/// component.section(&instances);
///
/// let bytes = component.finish();
/// ```
#[derive(Clone, Debug, Default)]
pub struct InstanceSection {
bytes: Vec<u8>,
num_added: u32,
}
impl InstanceSection {
/// Create a new core instance section encoder.
pub fn new() -> Self {
Self::default()
}
/// The number of instances 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 instance by instantiating a core module.
pub fn instantiate<A, S>(&mut self, module_index: u32, args: A) -> &mut Self
where
A: IntoIterator<Item = (S, ModuleArg)>,
A::IntoIter: ExactSizeIterator,
S: AsRef<str>,
{
let args = args.into_iter();
self.bytes.push(0x00);
module_index.encode(&mut self.bytes);
args.len().encode(&mut self.bytes);
for (name, arg) in args {
name.as_ref().encode(&mut self.bytes);
arg.encode(&mut self.bytes);
}
self.num_added += 1;
self
}
/// Define an instance by exporting core WebAssembly items.
pub fn export_items<E, S>(&mut self, exports: E) -> &mut Self
where
E: IntoIterator<Item = (S, ExportKind, u32)>,
E::IntoIter: ExactSizeIterator,
S: AsRef<str>,
{
let exports = exports.into_iter();
self.bytes.push(0x01);
exports.len().encode(&mut self.bytes);
for (name, kind, index) in exports {
name.as_ref().encode(&mut self.bytes);
kind.encode(&mut self.bytes);
index.encode(&mut self.bytes);
}
self.num_added += 1;
self
}
}
impl Encode for InstanceSection {
fn encode(&self, sink: &mut Vec<u8>) {
encode_section(sink, self.num_added, &self.bytes);
}
}
impl ComponentSection for InstanceSection {
fn id(&self) -> u8 {
ComponentSectionId::CoreInstance.into()
}
}
/// An encoder for the instance section of WebAssembly components.
///
/// # Example
///
/// ```rust
/// use wasm_encoder::{Component, ComponentInstanceSection, ComponentExportKind};
///
/// let mut instances = ComponentInstanceSection::new();
/// instances.export_items([("foo", ComponentExportKind::Func, 0)]);
/// instances.instantiate(1, [("foo", ComponentExportKind::Instance, 0)]);
///
/// let mut component = Component::new();
/// component.section(&instances);
///
/// let bytes = component.finish();
/// ```
#[derive(Clone, Debug, Default)]
pub struct ComponentInstanceSection {
bytes: Vec<u8>,
num_added: u32,
}
impl ComponentInstanceSection {
/// Create a new instance section encoder.
pub fn new() -> Self {
Self::default()
}
/// The number of instances 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 instance by instantiating a component.
pub fn instantiate<A, S>(&mut self, component_index: u32, args: A) -> &mut Self
where
A: IntoIterator<Item = (S, ComponentExportKind, u32)>,
A::IntoIter: ExactSizeIterator,
S: AsRef<str>,
{
let args = args.into_iter();
self.bytes.push(0x00);
component_index.encode(&mut self.bytes);
args.len().encode(&mut self.bytes);
for (name, kind, index) in args {
name.as_ref().encode(&mut self.bytes);
kind.encode(&mut self.bytes);
index.encode(&mut self.bytes);
}
self.num_added += 1;
self
}
/// Define an instance by exporting items.
pub fn export_items<'a, E>(&mut self, exports: E) -> &mut Self
where
E: IntoIterator<Item = (&'a str, ComponentExportKind, u32)>,
E::IntoIter: ExactSizeIterator,
{
let exports = exports.into_iter();
self.bytes.push(0x01);
exports.len().encode(&mut self.bytes);
for (name, kind, index) in exports {
crate::push_extern_name_byte(&mut self.bytes, name);
name.encode(&mut self.bytes);
kind.encode(&mut self.bytes);
index.encode(&mut self.bytes);
}
self.num_added += 1;
self
}
}
impl Encode for ComponentInstanceSection {
fn encode(&self, sink: &mut Vec<u8>) {
encode_section(sink, self.num_added, &self.bytes);
}
}
impl ComponentSection for ComponentInstanceSection {
fn id(&self) -> u8 {
ComponentSectionId::Instance.into()
}
}