Revision control
Copy as Markdown
Other Tools
use crate::annotation;
use crate::component::*;
use crate::core::{self, Producers};
use crate::kw;
use crate::parser::{Parse, Parser, Result};
use crate::token::Index;
use crate::token::{Id, NameAnnotation, Span};
/// A parsed WebAssembly component module.
#[derive(Debug)]
#[non_exhaustive]
pub struct Component<'a> {
/// Where this `component` was defined
pub span: Span,
/// An optional identifier this component is known by
pub id: Option<Id<'a>>,
/// An optional `@name` annotation for this component
pub name: Option<NameAnnotation<'a>>,
/// What kind of component this was parsed as.
pub kind: ComponentKind<'a>,
}
/// The different kinds of ways to define a component.
#[derive(Debug)]
pub enum ComponentKind<'a> {
/// A component defined in the textual s-expression format.
Text(Vec<ComponentField<'a>>),
/// A component that had its raw binary bytes defined via the `binary`
/// directive.
Binary(Vec<&'a [u8]>),
}
impl<'a> Component<'a> {
/// Performs a name resolution pass on this [`Component`], resolving all
/// symbolic names to indices.
///
/// The WAT format contains a number of shorthands to make it easier to
/// write, such as inline exports, inline imports, inline type definitions,
/// etc. Additionally it allows using symbolic names such as `$foo` instead
/// of using indices. This module will postprocess an AST to remove all of
/// this syntactic sugar, preparing the AST for binary emission. This is
/// where expansion and name resolution happens.
///
/// This function will mutate the AST of this [`Component`] and replace all
/// [`Index`](crate::token::Index) arguments with `Index::Num`. This will
/// also expand inline exports/imports listed on fields and handle various
/// other shorthands of the text format.
///
/// If successful the AST was modified to be ready for binary encoding.
///
/// # Errors
///
/// If an error happens during resolution, such a name resolution error or
/// items are found in the wrong order, then an error is returned.
pub fn resolve(&mut self) -> std::result::Result<(), crate::Error> {
match &mut self.kind {
ComponentKind::Text(fields) => {
crate::component::expand::expand(fields);
}
ComponentKind::Binary(_) => {}
}
crate::component::resolve::resolve(self)
}
/// Encodes this [`Component`] to its binary form.
///
/// This function will take the textual representation in [`Component`] and
/// perform all steps necessary to convert it to a binary WebAssembly
/// component, suitable for writing to a `*.wasm` file. This function may
/// internally modify the [`Component`], for example:
///
/// * Name resolution is performed to ensure that `Index::Id` isn't present
/// anywhere in the AST.
///
/// * Inline shorthands such as imports/exports/types are all expanded to be
/// dedicated fields of the component.
///
/// * Component fields may be shuffled around to preserve index ordering from
/// expansions.
///
/// After all of this expansion has happened the component will be converted to
/// its binary form and returned as a `Vec<u8>`. This is then suitable to
/// hand off to other wasm runtimes and such.
///
/// # Errors
///
/// This function can return an error for name resolution errors and other
/// expansion-related errors.
pub fn encode(&mut self) -> std::result::Result<Vec<u8>, crate::Error> {
crate::core::EncodeOptions::default().encode_component(self)
}
pub(crate) fn validate(&self, parser: Parser<'_>) -> Result<()> {
let mut starts = 0;
if let ComponentKind::Text(fields) = &self.kind {
for item in fields.iter() {
if let ComponentField::Start(_) = item {
starts += 1;
}
}
}
if starts > 1 {
return Err(parser.error("multiple start sections found"));
}
Ok(())
}
pub(crate) fn parse_without_component_keyword(
component_keyword_span: Span,
parser: Parser<'a>,
) -> Result<Self> {
let id = parser.parse()?;
let name = parser.parse()?;
let kind = if parser.peek::<kw::binary>()? {
parser.parse::<kw::binary>()?;
let mut data = Vec::new();
while !parser.is_empty() {
data.push(parser.parse()?);
}
ComponentKind::Binary(data)
} else {
ComponentKind::Text(ComponentField::parse_remaining(parser)?)
};
Ok(Component {
span: component_keyword_span,
id,
name,
kind,
})
}
}
impl<'a> Parse<'a> for Component<'a> {
fn parse(parser: Parser<'a>) -> Result<Self> {
parser.with_standard_annotations_registered(|parser| {
let span = parser.parse::<kw::component>()?.0;
Component::parse_without_component_keyword(span, parser)
})
}
}
/// A listing of all possible fields that can make up a WebAssembly component.
#[allow(missing_docs)]
#[derive(Debug)]
pub enum ComponentField<'a> {
CoreModule(CoreModule<'a>),
CoreInstance(CoreInstance<'a>),
CoreType(CoreType<'a>),
CoreRec(core::Rec<'a>),
Component(NestedComponent<'a>),
Instance(Instance<'a>),
Alias(Alias<'a>),
Type(Type<'a>),
CanonicalFunc(CanonicalFunc<'a>),
CoreFunc(CoreFunc<'a>), // Supports inverted forms of other items
Func(Func<'a>), // Supports inverted forms of other items
Start(Start<'a>),
Import(ComponentImport<'a>),
Export(ComponentExport<'a>),
Custom(Custom<'a>),
Producers(Producers<'a>),
}
impl<'a> ComponentField<'a> {
fn parse_remaining(parser: Parser<'a>) -> Result<Vec<ComponentField<'a>>> {
let mut fields = Vec::new();
while !parser.is_empty() {
fields.push(parser.parens(ComponentField::parse)?);
}
Ok(fields)
}
}
impl<'a> Parse<'a> for ComponentField<'a> {
fn parse(parser: Parser<'a>) -> Result<Self> {
if parser.peek::<kw::core>()? {
if parser.peek2::<kw::module>()? {
return Ok(Self::CoreModule(parser.parse()?));
}
if parser.peek2::<kw::instance>()? {
return Ok(Self::CoreInstance(parser.parse()?));
}
if parser.peek2::<kw::r#type>()? {
return Ok(Self::CoreType(parser.parse()?));
}
if parser.peek2::<kw::func>()? {
return Ok(Self::CoreFunc(parser.parse()?));
}
if parser.peek2::<kw::rec>()? {
parser.parse::<kw::core>()?;
return Ok(Self::CoreRec(parser.parse()?));
}
} else {
if parser.peek::<kw::component>()? {
return Ok(Self::Component(parser.parse()?));
}
if parser.peek::<kw::instance>()? {
return Ok(Self::Instance(parser.parse()?));
}
if parser.peek::<kw::alias>()? {
return Ok(Self::Alias(parser.parse()?));
}
if parser.peek::<kw::r#type>()? {
return Ok(Self::Type(Type::parse_maybe_with_inline_exports(parser)?));
}
if parser.peek::<kw::import>()? {
return Ok(Self::Import(parser.parse()?));
}
if parser.peek::<kw::func>()? {
return Ok(Self::Func(parser.parse()?));
}
if parser.peek::<kw::export>()? {
return Ok(Self::Export(parser.parse()?));
}
if parser.peek::<kw::start>()? {
return Ok(Self::Start(parser.parse()?));
}
if parser.peek::<annotation::custom>()? {
return Ok(Self::Custom(parser.parse()?));
}
if parser.peek::<annotation::producers>()? {
return Ok(Self::Producers(parser.parse()?));
}
}
Err(parser.error("expected valid component field"))
}
}
/// A function to call at instantiation time.
#[derive(Debug)]
pub struct Start<'a> {
/// The function to call.
pub func: Index<'a>,
/// The arguments to pass to the function.
pub args: Vec<ItemRef<'a, kw::value>>,
/// Names of the result values.
pub results: Vec<Option<Id<'a>>>,
}
impl<'a> Parse<'a> for Start<'a> {
fn parse(parser: Parser<'a>) -> Result<Self> {
parser.parse::<kw::start>()?;
let func = parser.parse()?;
let mut args = Vec::new();
while !parser.is_empty() && !parser.peek2::<kw::result>()? {
args.push(parser.parens(|parser| parser.parse())?);
}
let mut results = Vec::new();
while !parser.is_empty() && parser.peek2::<kw::result>()? {
results.push(parser.parens(|parser| {
parser.parse::<kw::result>()?;
parser.parens(|parser| {
parser.parse::<kw::value>()?;
parser.parse()
})
})?);
}
Ok(Start {
func,
args,
results,
})
}
}
/// A nested WebAssembly component.
#[derive(Debug)]
pub struct NestedComponent<'a> {
/// Where this `component` was defined
pub span: Span,
/// An optional identifier this component is known by
pub id: Option<Id<'a>>,
/// An optional `@name` annotation for this component
pub name: Option<NameAnnotation<'a>>,
/// If present, inline export annotations which indicate names this
/// definition should be exported under.
pub exports: InlineExport<'a>,
/// What kind of component this was parsed as.
pub kind: NestedComponentKind<'a>,
}
/// The different kinds of ways to define a nested component.
#[derive(Debug)]
pub enum NestedComponentKind<'a> {
/// This is actually an inline import of a component
Import {
/// The information about where this is being imported from.
import: InlineImport<'a>,
/// The type of component being imported.
ty: ComponentTypeUse<'a, ComponentType<'a>>,
},
/// The component is defined inline as a local definition with its fields
/// listed here.
Inline(Vec<ComponentField<'a>>),
}
impl<'a> Parse<'a> for NestedComponent<'a> {
fn parse(parser: Parser<'a>) -> Result<Self> {
parser.depth_check()?;
let span = parser.parse::<kw::component>()?.0;
let id = parser.parse()?;
let name = parser.parse()?;
let exports = parser.parse()?;
let kind = if let Some(import) = parser.parse()? {
NestedComponentKind::Import {
import,
ty: parser.parse()?,
}
} else {
let mut fields = Vec::new();
while !parser.is_empty() {
fields.push(parser.parens(|p| p.parse())?);
}
NestedComponentKind::Inline(fields)
};
Ok(NestedComponent {
span,
id,
name,
exports,
kind,
})
}
}