Files
wasmtime/crates/wit-bindgen/src/rust.rs
Dan Gohman c19b742d1c Change the name of wit-bindgen's host implementation traits. (#5890)
* Change the name of wit-bindgen's host implementation traits.

Instead of naming the host implementation trait something like
`wasi_filesystem::WasiFilesystem`, name it `wasi_filesystem::Host`, and
avoid using the identifier `Host` in other places.

This fixes a collision when generating bindings for the current
wasi-clock API, which contains an interface `wall-clock` which contains
a type `wall-clock`, which created a naming collision on the name
`WallClock`.

* Update tests to use the new trait name.

* Fix one more.

* Add the new test interface to the simple-wasi world.
2023-02-27 23:14:55 +00:00

439 lines
16 KiB
Rust

use crate::types::TypeInfo;
use heck::*;
use std::collections::HashMap;
use std::fmt::Write;
use wit_parser::*;
#[derive(Debug, Copy, Clone, PartialEq)]
pub enum TypeMode {
Owned,
AllBorrowed(&'static str),
}
pub trait RustGenerator<'a> {
fn resolve(&self) -> &'a Resolve;
fn push_str(&mut self, s: &str);
fn info(&self, ty: TypeId) -> TypeInfo;
fn current_interface(&self) -> Option<InterfaceId>;
fn print_ty(&mut self, ty: &Type, mode: TypeMode) {
match ty {
Type::Id(t) => self.print_tyid(*t, mode),
Type::Bool => self.push_str("bool"),
Type::U8 => self.push_str("u8"),
Type::U16 => self.push_str("u16"),
Type::U32 => self.push_str("u32"),
Type::U64 => self.push_str("u64"),
Type::S8 => self.push_str("i8"),
Type::S16 => self.push_str("i16"),
Type::S32 => self.push_str("i32"),
Type::S64 => self.push_str("i64"),
Type::Float32 => self.push_str("f32"),
Type::Float64 => self.push_str("f64"),
Type::Char => self.push_str("char"),
Type::String => match mode {
TypeMode::AllBorrowed(lt) => {
self.push_str("&");
if lt != "'_" {
self.push_str(lt);
self.push_str(" ");
}
self.push_str("str");
}
TypeMode::Owned => self.push_str("String"),
},
}
}
fn print_optional_ty(&mut self, ty: Option<&Type>, mode: TypeMode) {
match ty {
Some(ty) => self.print_ty(ty, mode),
None => self.push_str("()"),
}
}
fn print_tyid(&mut self, id: TypeId, mode: TypeMode) {
let info = self.info(id);
let lt = self.lifetime_for(&info, mode);
let ty = &self.resolve().types[id];
if ty.name.is_some() {
let name = if lt.is_some() {
self.param_name(id)
} else {
self.result_name(id)
};
if let TypeOwner::Interface(id) = ty.owner {
if let Some(name) = &self.resolve().interfaces[id].name {
match self.current_interface() {
Some(cur) if cur == id => {}
Some(_other) => {
self.push_str("super::");
self.push_str(&name.to_snake_case());
self.push_str("::");
}
None => {
self.push_str(&name.to_snake_case());
self.push_str("::");
}
}
}
}
self.push_str(&name);
// If the type recursively owns data and it's a
// variant/record/list, then we need to place the
// lifetime parameter on the type as well.
if info.has_list && needs_generics(self.resolve(), &ty.kind) {
self.print_generics(lt);
}
return;
fn needs_generics(resolve: &Resolve, ty: &TypeDefKind) -> bool {
match ty {
TypeDefKind::Variant(_)
| TypeDefKind::Record(_)
| TypeDefKind::Option(_)
| TypeDefKind::Result(_)
| TypeDefKind::Future(_)
| TypeDefKind::Stream(_)
| TypeDefKind::List(_)
| TypeDefKind::Flags(_)
| TypeDefKind::Enum(_)
| TypeDefKind::Tuple(_)
| TypeDefKind::Union(_) => true,
TypeDefKind::Type(Type::Id(t)) => {
needs_generics(resolve, &resolve.types[*t].kind)
}
TypeDefKind::Type(Type::String) => true,
TypeDefKind::Type(_) => false,
TypeDefKind::Unknown => unreachable!(),
}
}
}
match &ty.kind {
TypeDefKind::List(t) => self.print_list(t, mode),
TypeDefKind::Option(t) => {
self.push_str("Option<");
self.print_ty(t, mode);
self.push_str(">");
}
TypeDefKind::Result(r) => {
self.push_str("Result<");
self.print_optional_ty(r.ok.as_ref(), mode);
self.push_str(",");
self.print_optional_ty(r.err.as_ref(), mode);
self.push_str(">");
}
TypeDefKind::Variant(_) => panic!("unsupported anonymous variant"),
// Tuple-like records are mapped directly to Rust tuples of
// types. Note the trailing comma after each member to
// appropriately handle 1-tuples.
TypeDefKind::Tuple(t) => {
self.push_str("(");
for ty in t.types.iter() {
self.print_ty(ty, mode);
self.push_str(",");
}
self.push_str(")");
}
TypeDefKind::Record(_) => {
panic!("unsupported anonymous type reference: record")
}
TypeDefKind::Flags(_) => {
panic!("unsupported anonymous type reference: flags")
}
TypeDefKind::Enum(_) => {
panic!("unsupported anonymous type reference: enum")
}
TypeDefKind::Union(_) => {
panic!("unsupported anonymous type reference: union")
}
TypeDefKind::Future(ty) => {
self.push_str("Future<");
self.print_optional_ty(ty.as_ref(), mode);
self.push_str(">");
}
TypeDefKind::Stream(stream) => {
self.push_str("Stream<");
self.print_optional_ty(stream.element.as_ref(), mode);
self.push_str(",");
self.print_optional_ty(stream.end.as_ref(), mode);
self.push_str(">");
}
TypeDefKind::Type(t) => self.print_ty(t, mode),
TypeDefKind::Unknown => unreachable!(),
}
}
fn print_list(&mut self, ty: &Type, mode: TypeMode) {
match mode {
TypeMode::AllBorrowed(lt) => {
self.push_str("&");
if lt != "'_" {
self.push_str(lt);
self.push_str(" ");
}
self.push_str("[");
self.print_ty(ty, mode);
self.push_str("]");
}
TypeMode::Owned => {
self.push_str("Vec<");
self.print_ty(ty, mode);
self.push_str(">");
}
}
}
fn print_generics(&mut self, lifetime: Option<&str>) {
if lifetime.is_none() {
return;
}
self.push_str("<");
if let Some(lt) = lifetime {
self.push_str(lt);
self.push_str(",");
}
self.push_str(">");
}
fn modes_of(&self, ty: TypeId) -> Vec<(String, TypeMode)> {
let info = self.info(ty);
let mut result = Vec::new();
if info.borrowed {
result.push((self.param_name(ty), TypeMode::AllBorrowed("'a")));
}
if info.owned && (!info.borrowed || self.uses_two_names(&info)) {
result.push((self.result_name(ty), TypeMode::Owned));
}
return result;
}
/// Writes the camel-cased 'name' of the passed type to `out`, as used to name union variants.
fn write_name(&self, ty: &Type, out: &mut String) {
match ty {
Type::Bool => out.push_str("Bool"),
Type::U8 => out.push_str("U8"),
Type::U16 => out.push_str("U16"),
Type::U32 => out.push_str("U32"),
Type::U64 => out.push_str("U64"),
Type::S8 => out.push_str("I8"),
Type::S16 => out.push_str("I16"),
Type::S32 => out.push_str("I32"),
Type::S64 => out.push_str("I64"),
Type::Float32 => out.push_str("F32"),
Type::Float64 => out.push_str("F64"),
Type::Char => out.push_str("Char"),
Type::String => out.push_str("String"),
Type::Id(id) => {
let ty = &self.resolve().types[*id];
match &ty.name {
Some(name) => out.push_str(&name.to_upper_camel_case()),
None => match &ty.kind {
TypeDefKind::Option(ty) => {
out.push_str("Optional");
self.write_name(ty, out);
}
TypeDefKind::Result(_) => out.push_str("Result"),
TypeDefKind::Tuple(_) => out.push_str("Tuple"),
TypeDefKind::List(ty) => {
self.write_name(ty, out);
out.push_str("List")
}
TypeDefKind::Future(ty) => {
self.write_optional_name(ty.as_ref(), out);
out.push_str("Future");
}
TypeDefKind::Stream(s) => {
self.write_optional_name(s.element.as_ref(), out);
self.write_optional_name(s.end.as_ref(), out);
out.push_str("Stream");
}
TypeDefKind::Type(ty) => self.write_name(ty, out),
TypeDefKind::Record(_) => out.push_str("Record"),
TypeDefKind::Flags(_) => out.push_str("Flags"),
TypeDefKind::Variant(_) => out.push_str("Variant"),
TypeDefKind::Enum(_) => out.push_str("Enum"),
TypeDefKind::Union(_) => out.push_str("Union"),
TypeDefKind::Unknown => unreachable!(),
},
}
}
}
}
fn write_optional_name(&self, ty: Option<&Type>, out: &mut String) {
match ty {
Some(ty) => self.write_name(ty, out),
None => out.push_str("()"),
}
}
/// Returns the names for the cases of the passed union.
fn union_case_names(&self, union: &Union) -> Vec<String> {
enum UsedState<'a> {
/// This name has been used once before.
///
/// Contains a reference to the name given to the first usage so that a suffix can be added to it.
Once(&'a mut String),
/// This name has already been used multiple times.
///
/// Contains the number of times this has already been used.
Multiple(usize),
}
// A `Vec` of the names we're assigning each of the union's cases in order.
let mut case_names = vec![String::new(); union.cases.len()];
// A map from case names to their `UsedState`.
let mut used = HashMap::new();
for (case, name) in union.cases.iter().zip(case_names.iter_mut()) {
self.write_name(&case.ty, name);
match used.get_mut(name.as_str()) {
None => {
// Initialise this name's `UsedState`, with a mutable reference to this name
// in case we have to add a suffix to it later.
used.insert(name.clone(), UsedState::Once(name));
// Since this is the first (and potentially only) usage of this name,
// we don't need to add a suffix here.
}
Some(state) => match state {
UsedState::Multiple(n) => {
// Add a suffix of the index of this usage.
write!(name, "{n}").unwrap();
// Add one to the number of times this type has been used.
*n += 1;
}
UsedState::Once(first) => {
// Add a suffix of 0 to the first usage.
first.push('0');
// We now get a suffix of 1.
name.push('1');
// Then update the state.
*state = UsedState::Multiple(2);
}
},
}
}
case_names
}
fn param_name(&self, ty: TypeId) -> String {
let info = self.info(ty);
let name = self.resolve().types[ty]
.name
.as_ref()
.unwrap()
.to_upper_camel_case();
if self.uses_two_names(&info) {
format!("{}Param", name)
} else {
name
}
}
fn result_name(&self, ty: TypeId) -> String {
let info = self.info(ty);
let name = self.resolve().types[ty]
.name
.as_ref()
.unwrap()
.to_upper_camel_case();
if self.uses_two_names(&info) {
format!("{}Result", name)
} else {
name
}
}
fn uses_two_names(&self, info: &TypeInfo) -> bool {
info.has_list && info.borrowed && info.owned
}
fn lifetime_for(&self, info: &TypeInfo, mode: TypeMode) -> Option<&'static str> {
match mode {
TypeMode::AllBorrowed(s) if info.has_list => Some(s),
_ => None,
}
}
}
/// Translate `name` to a Rust `snake_case` identifier.
pub fn to_rust_ident(name: &str) -> String {
match name {
// Escape Rust keywords.
// Source: https://doc.rust-lang.org/reference/keywords.html
"as" => "as_".into(),
"break" => "break_".into(),
"const" => "const_".into(),
"continue" => "continue_".into(),
"crate" => "crate_".into(),
"else" => "else_".into(),
"enum" => "enum_".into(),
"extern" => "extern_".into(),
"false" => "false_".into(),
"fn" => "fn_".into(),
"for" => "for_".into(),
"if" => "if_".into(),
"impl" => "impl_".into(),
"in" => "in_".into(),
"let" => "let_".into(),
"loop" => "loop_".into(),
"match" => "match_".into(),
"mod" => "mod_".into(),
"move" => "move_".into(),
"mut" => "mut_".into(),
"pub" => "pub_".into(),
"ref" => "ref_".into(),
"return" => "return_".into(),
"self" => "self_".into(),
"static" => "static_".into(),
"struct" => "struct_".into(),
"super" => "super_".into(),
"trait" => "trait_".into(),
"true" => "true_".into(),
"type" => "type_".into(),
"unsafe" => "unsafe_".into(),
"use" => "use_".into(),
"where" => "where_".into(),
"while" => "while_".into(),
"async" => "async_".into(),
"await" => "await_".into(),
"dyn" => "dyn_".into(),
"abstract" => "abstract_".into(),
"become" => "become_".into(),
"box" => "box_".into(),
"do" => "do_".into(),
"final" => "final_".into(),
"macro" => "macro_".into(),
"override" => "override_".into(),
"priv" => "priv_".into(),
"typeof" => "typeof_".into(),
"unsized" => "unsized_".into(),
"virtual" => "virtual_".into(),
"yield" => "yield_".into(),
"try" => "try_".into(),
s => s.to_snake_case(),
}
}
/// Translate `name` to a Rust `UpperCamelCase` identifier.
pub fn to_rust_upper_camel_case(name: &str) -> String {
match name {
// We use `Host` as the name of the trait for host implementations
// to fill in, so rename it if "Host" is used as a regular identifier.
"host" => "Host_".into(),
s => s.to_upper_camel_case(),
}
}