Revision control
Copy as Markdown
Other Tools
use crate::{
BinaryReader, ComponentExternalKind, ComponentValType, FromReader, Result, SectionLimited,
};
/// Represents the type bounds for imports and exports.
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub enum TypeBounds {
/// The type is bounded by equality.
Eq(u32),
/// A fresh resource type,
SubResource,
}
impl<'a> FromReader<'a> for TypeBounds {
fn from_reader(reader: &mut BinaryReader<'a>) -> Result<Self> {
Ok(match reader.read_u8()? {
0x00 => TypeBounds::Eq(reader.read()?),
0x01 => TypeBounds::SubResource,
x => return reader.invalid_leading_byte(x, "type bound"),
})
}
}
/// Represents a reference to a component type.
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub enum ComponentTypeRef {
/// The reference is to a core module type.
///
/// The index is expected to be core type index to a core module type.
Module(u32),
/// The reference is to a function type.
///
/// The index is expected to be a type index to a function type.
Func(u32),
/// The reference is to a value type.
Value(ComponentValType),
/// The reference is to a bounded type.
///
/// The index is expected to be a type index.
Type(TypeBounds),
/// The reference is to an instance type.
///
/// The index is a type index to an instance type.
Instance(u32),
/// The reference is to a component type.
///
/// The index is a type index to a component type.
Component(u32),
}
impl ComponentTypeRef {
/// Returns the corresponding [`ComponentExternalKind`] for this reference.
pub fn kind(&self) -> ComponentExternalKind {
match self {
ComponentTypeRef::Module(_) => ComponentExternalKind::Module,
ComponentTypeRef::Func(_) => ComponentExternalKind::Func,
ComponentTypeRef::Value(_) => ComponentExternalKind::Value,
ComponentTypeRef::Type(..) => ComponentExternalKind::Type,
ComponentTypeRef::Instance(_) => ComponentExternalKind::Instance,
ComponentTypeRef::Component(_) => ComponentExternalKind::Component,
}
}
}
impl<'a> FromReader<'a> for ComponentTypeRef {
fn from_reader(reader: &mut BinaryReader<'a>) -> Result<Self> {
Ok(match reader.read()? {
ComponentExternalKind::Module => ComponentTypeRef::Module(reader.read()?),
ComponentExternalKind::Func => ComponentTypeRef::Func(reader.read()?),
ComponentExternalKind::Value => ComponentTypeRef::Value(reader.read()?),
ComponentExternalKind::Type => ComponentTypeRef::Type(reader.read()?),
ComponentExternalKind::Instance => ComponentTypeRef::Instance(reader.read()?),
ComponentExternalKind::Component => ComponentTypeRef::Component(reader.read()?),
})
}
}
/// Represents an import in a WebAssembly component
#[derive(Debug, Copy, Clone, Eq, PartialEq)]
pub struct ComponentImport<'a> {
/// The name of the imported item.
pub name: ComponentImportName<'a>,
/// The type reference for the import.
pub ty: ComponentTypeRef,
}
impl<'a> FromReader<'a> for ComponentImport<'a> {
fn from_reader(reader: &mut BinaryReader<'a>) -> Result<Self> {
Ok(ComponentImport {
name: reader.read()?,
ty: reader.read()?,
})
}
}
/// A reader for the import section of a WebAssembly component.
///
/// # Examples
///
/// ```
/// use wasmparser::{ComponentImportSectionReader, BinaryReader};
/// let data: &[u8] = &[0x01, 0x00, 0x01, 0x41, 0x01, 0x66];
/// let reader = BinaryReader::new(data, 0);
/// let reader = ComponentImportSectionReader::new(reader).unwrap();
/// for import in reader {
/// let import = import.expect("import");
/// println!("Import: {:?}", import);
/// }
/// ```
pub type ComponentImportSectionReader<'a> = SectionLimited<'a, ComponentImport<'a>>;
/// Represents the name of a component import.
#[derive(Debug, Copy, Clone, Eq, PartialEq)]
#[allow(missing_docs)]
pub struct ComponentImportName<'a>(pub &'a str);
impl<'a> FromReader<'a> for ComponentImportName<'a> {
fn from_reader(reader: &mut BinaryReader<'a>) -> Result<Self> {
match reader.read_u8()? {
// This is the spec-required byte as of this time.
0x00 => {}
// Prior to WebAssembly/component-model#263 export names used a
// discriminator byte of 0x01 to indicate an "interface" of the
// form `a:b/c` but nowadays that's inferred from string syntax.
// Ignore 0-vs-1 to continue to parse older binaries. Eventually
// this will go away.
//
// This logic to ignore 0x01 was landed on 2023-10-28 in
// bytecodealliance/wasm-tools#1262 and the encoder at the time
// still emitted 0x01 to have better compatibility with prior
// validators.
//
// On 2024-09-03 in bytecodealliance/wasm-tools#TODO the encoder
// was updated to always emit 0x00 as a leading byte. After enough
// time has passed this case may be able to be removed. When
// removing this it's probably best to do it with a `WasmFeatures`
// flag first to ensure there's an opt-in way of fixing things.
0x01 => {}
x => return reader.invalid_leading_byte(x, "import name"),
}
Ok(ComponentImportName(reader.read_string()?))
}
}