Files
wasmer/lib/js-api/src/resolver.rs
2021-06-21 21:14:16 -07:00

78 lines
2.7 KiB
Rust

use crate::export::Export;
use wasmer_types::entity::{BoxedSlice, EntityRef, PrimaryMap};
use wasmer_types::{ExternType, FunctionIndex, ImportIndex, MemoryIndex, TableIndex};
/// Import resolver connects imports with available exported values.
pub trait Resolver: Sized {
/// Resolves an import a WebAssembly module to an export it's hooked up to.
///
/// The `index` provided is the index of the import in the wasm module
/// that's being resolved. For example 1 means that it's the second import
/// listed in the wasm module.
///
/// The `module` and `field` arguments provided are the module/field names
/// listed on the import itself.
///
/// # Notes:
///
/// The index is useful because some WebAssembly modules may rely on that
/// for resolving ambiguity in their imports. Such as:
/// ```ignore
/// (module
/// (import "" "" (func))
/// (import "" "" (func (param i32) (result i32)))
/// )
/// ```
fn resolve(&self, _index: u32, module: &str, field: &str) -> Option<Export>;
}
/// Import resolver connects imports with available exported values.
///
/// This is a specific subtrait for [`Resolver`] for those users who don't
/// care about the `index`, but only about the `module` and `field` for
/// the resolution.
pub trait NamedResolver {
/// Resolves an import a WebAssembly module to an export it's hooked up to.
///
/// It receives the `module` and `field` names and return the [`Export`] in
/// case it's found.
fn resolve_by_name(&self, module: &str, field: &str) -> Option<Export>;
}
// All NamedResolvers should extend `Resolver`.
impl<T: NamedResolver> Resolver for T {
/// By default this method will be calling [`NamedResolver::resolve_by_name`],
/// dismissing the provided `index`.
fn resolve(&self, _index: u32, module: &str, field: &str) -> Option<Export> {
self.resolve_by_name(module, field)
}
}
impl<T: NamedResolver> NamedResolver for &T {
fn resolve_by_name(&self, module: &str, field: &str) -> Option<Export> {
(**self).resolve_by_name(module, field)
}
}
impl NamedResolver for Box<dyn NamedResolver> {
fn resolve_by_name(&self, module: &str, field: &str) -> Option<Export> {
(**self).resolve_by_name(module, field)
}
}
impl NamedResolver for () {
/// Always returns `None`.
fn resolve_by_name(&self, _module: &str, _field: &str) -> Option<Export> {
None
}
}
/// `Resolver` implementation that always resolves to `None`. Equivalent to `()`.
pub struct NullResolver {}
impl Resolver for NullResolver {
fn resolve(&self, _idx: u32, _module: &str, _field: &str) -> Option<Export> {
None
}
}