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use escaping::{escape_id, handle_2big_enum_variant, NamingConvention};
use heck::{ToShoutySnakeCase, ToSnakeCase};
use proc_macro2::{Ident, TokenStream};
use quote::{format_ident, quote};
use witx::{BuiltinType, Id, Type, TypeRef, WasmType};
use crate::{lifetimes::LifetimeExt, UserErrorType};
pub struct Names {
runtime_mod: TokenStream,
}
impl Names {
pub fn new(runtime_mod: TokenStream) -> Names {
Names { runtime_mod }
}
pub fn runtime_mod(&self) -> TokenStream {
self.runtime_mod.clone()
}
pub fn type_(&self, id: &Id) -> TokenStream {
let ident = escape_id(id, NamingConvention::CamelCase);
quote!(#ident)
}
pub fn builtin_type(&self, b: BuiltinType) -> TokenStream {
match b {
BuiltinType::U8 { .. } => quote!(u8),
BuiltinType::U16 => quote!(u16),
BuiltinType::U32 { .. } => quote!(u32),
BuiltinType::U64 => quote!(u64),
BuiltinType::S8 => quote!(i8),
BuiltinType::S16 => quote!(i16),
BuiltinType::S32 => quote!(i32),
BuiltinType::S64 => quote!(i64),
BuiltinType::F32 => quote!(f32),
BuiltinType::F64 => quote!(f64),
BuiltinType::Char => quote!(char),
}
}
pub fn wasm_type(&self, ty: WasmType) -> TokenStream {
match ty {
WasmType::I32 => quote!(i32),
WasmType::I64 => quote!(i64),
WasmType::F32 => quote!(f32),
WasmType::F64 => quote!(f64),
}
}
pub fn type_ref(&self, tref: &TypeRef, lifetime: TokenStream) -> TokenStream {
match tref {
TypeRef::Name(nt) => {
let ident = self.type_(&nt.name);
if nt.tref.needs_lifetime() {
quote!(#ident<#lifetime>)
} else {
quote!(#ident)
}
}
TypeRef::Value(ty) => match &**ty {
Type::Builtin(builtin) => self.builtin_type(*builtin),
Type::Pointer(pointee) | Type::ConstPointer(pointee) => {
let rt = self.runtime_mod();
let pointee_type = self.type_ref(&pointee, lifetime.clone());
quote!(#rt::GuestPtr<#lifetime, #pointee_type>)
}
Type::List(pointee) => match &**pointee.type_() {
Type::Builtin(BuiltinType::Char) => {
let rt = self.runtime_mod();
quote!(#rt::GuestPtr<#lifetime, str>)
}
_ => {
let rt = self.runtime_mod();
let pointee_type = self.type_ref(&pointee, lifetime.clone());
quote!(#rt::GuestPtr<#lifetime, [#pointee_type]>)
}
},
Type::Variant(v) => match v.as_expected() {
Some((ok, err)) => {
let ok = match ok {
Some(ty) => self.type_ref(ty, lifetime.clone()),
None => quote!(()),
};
let err = match err {
Some(ty) => self.type_ref(ty, lifetime.clone()),
None => quote!(()),
};
quote!(Result<#ok, #err>)
}
None => unimplemented!("anonymous variant ref {:?}", tref),
},
Type::Record(r) if r.is_tuple() => {
let types = r
.members
.iter()
.map(|m| self.type_ref(&m.tref, lifetime.clone()))
.collect::<Vec<_>>();
quote!((#(#types,)*))
}
_ => unimplemented!("anonymous type ref {:?}", tref),
},
}
}
/// Convert an enum variant from its [`Id`][witx] name to its Rust [`Ident`][id] representation.
///
/// [id]: https://docs.rs/proc-macro2/*/proc_macro2/struct.Ident.html
/// [witx]: https://docs.rs/witx/*/witx/struct.Id.html
pub fn enum_variant(&self, id: &Id) -> Ident {
handle_2big_enum_variant(id).unwrap_or_else(|| escape_id(id, NamingConvention::CamelCase))
}
pub fn flag_member(&self, id: &Id) -> Ident {
format_ident!("{}", id.as_str().to_shouty_snake_case())
}
pub fn int_member(&self, id: &Id) -> Ident {
format_ident!("{}", id.as_str().to_shouty_snake_case())
}
/// Convert a struct member from its [`Id`][witx] name to its Rust [`Ident`][id] representation.
///
/// [id]: https://docs.rs/proc-macro2/*/proc_macro2/struct.Ident.html
/// [witx]: https://docs.rs/witx/*/witx/struct.Id.html
pub fn struct_member(&self, id: &Id) -> Ident {
escape_id(id, NamingConvention::SnakeCase)
}
/// Convert a module name from its [`Id`][witx] name to its Rust [`Ident`][id] representation.
///
/// [id]: https://docs.rs/proc-macro2/*/proc_macro2/struct.Ident.html
/// [witx]: https://docs.rs/witx/*/witx/struct.Id.html
pub fn module(&self, id: &Id) -> Ident {
escape_id(id, NamingConvention::SnakeCase)
}
/// Convert a trait name from its [`Id`][witx] name to its Rust [`Ident`][id] representation.
///
/// [id]: https://docs.rs/proc-macro2/*/proc_macro2/struct.Ident.html
/// [witx]: https://docs.rs/witx/*/witx/struct.Id.html
pub fn trait_name(&self, id: &Id) -> Ident {
escape_id(id, NamingConvention::CamelCase)
}
/// Convert a function name from its [`Id`][witx] name to its Rust [`Ident`][id] representation.
///
/// [id]: https://docs.rs/proc-macro2/*/proc_macro2/struct.Ident.html
/// [witx]: https://docs.rs/witx/*/witx/struct.Id.html
pub fn func(&self, id: &Id) -> Ident {
escape_id(id, NamingConvention::SnakeCase)
}
/// Convert a parameter name from its [`Id`][witx] name to its Rust [`Ident`][id] representation.
///
/// [id]: https://docs.rs/proc-macro2/*/proc_macro2/struct.Ident.html
/// [witx]: https://docs.rs/witx/*/witx/struct.Id.html
pub fn func_param(&self, id: &Id) -> Ident {
escape_id(id, NamingConvention::SnakeCase)
}
/// For when you need a {name}_ptr binding for passing a value by reference:
pub fn func_ptr_binding(&self, id: &Id) -> Ident {
format_ident!("{}_ptr", id.as_str().to_snake_case())
}
/// For when you need a {name}_len binding for passing an array:
pub fn func_len_binding(&self, id: &Id) -> Ident {
format_ident!("{}_len", id.as_str().to_snake_case())
}
fn builtin_name(b: &BuiltinType) -> &'static str {
match b {
BuiltinType::U8 { .. } => "u8",
BuiltinType::U16 => "u16",
BuiltinType::U32 { .. } => "u32",
BuiltinType::U64 => "u64",
BuiltinType::S8 => "i8",
BuiltinType::S16 => "i16",
BuiltinType::S32 => "i32",
BuiltinType::S64 => "i64",
BuiltinType::F32 => "f32",
BuiltinType::F64 => "f64",
BuiltinType::Char => "char",
}
}
fn snake_typename(tref: &TypeRef) -> String {
match tref {
TypeRef::Name(nt) => nt.name.as_str().to_snake_case(),
TypeRef::Value(ty) => match &**ty {
Type::Builtin(b) => Self::builtin_name(&b).to_owned(),
_ => panic!("unexpected anonymous type: {:?}", ty),
},
}
}
pub fn user_error_conversion_method(&self, user_type: &UserErrorType) -> Ident {
let abi_type = Self::snake_typename(&user_type.abi_type());
format_ident!(
"{}_from_{}",
abi_type,
user_type.method_fragment().to_snake_case()
)
}
}
/// Identifier escaping utilities.
///
/// This module most importantly exports an `escape_id` function that can be used to properly
/// escape tokens that conflict with strict and reserved keywords, as of Rust's 2018 edition.
///
/// Weak keywords are not included as their semantic rules do not have the same implications as
/// those of strict and reserved keywords. `union` for example, is permitted as the name of a
/// variable. `dyn` was promoted to a strict keyword beginning in the 2018 edition.
mod escaping {
use {
heck::{ToSnakeCase, ToUpperCamelCase},
proc_macro2::Ident,
quote::format_ident,
witx::Id,
};
/// Identifier naming convention.
///
/// Because shouty snake case values (identifiers that look `LIKE_THIS`) cannot potentially
/// conflict with any Rust keywords, this enum only include snake and camel case variants.
pub enum NamingConvention {
/// Snake case. Used to denote values `LikeThis`.
CamelCase,
/// Snake case. Used to denote values `like_this`.
SnakeCase,
}
/// Given a witx [`Id`][witx] and a [`NamingConvention`][naming], return a [`Ident`] word of
/// Rust syntax that accounts for escaping both strict and reserved keywords. If an identifier
/// would have conflicted with a keyword, a trailing underscode will be appended.
///
/// [id]: https://docs.rs/proc-macro2/*/proc_macro2/struct.Ident.html
/// [naming]: enum.NamingConvention.html
/// [witx]: https://docs.rs/witx/*/witx/struct.Id.html
pub fn escape_id(id: &Id, conv: NamingConvention) -> Ident {
use NamingConvention::{CamelCase, SnakeCase};
match (conv, id.as_str()) {
// For camel-cased identifiers, `Self` is the only potential keyword conflict.
(CamelCase, "self") => format_ident!("Self_"),
(CamelCase, s) => format_ident!("{}", s.to_upper_camel_case()),
// Snake-cased identifiers are where the bulk of conflicts can occur.
(SnakeCase, s) => {
let s = s.to_snake_case();
if STRICT.iter().chain(RESERVED).any(|k| *k == s) {
// If the camel-cased string matched any strict or reserved keywords, then
// append a trailing underscore to the identifier we generate.
format_ident!("{}_", s)
} else {
format_ident!("{}", s) // Otherwise, use the string as is.
}
}
}
}
/// Strict keywords.
///
/// > Strict keywords cannot be used as the names of:
/// > * Items
/// > * Variables and function parameters
/// > * Fields and variants
/// > * Type parameters
/// > * Lifetime parameters or loop labels
/// > * Macros or attributes
/// > * Macro placeholders
/// > * Crates
/// >
/// > - <cite>[The Rust Reference][ref]</cite>
///
/// This list also includes keywords that were introduced in the 2018 edition of Rust.
///
/// [ref]: https://doc.rust-lang.org/reference/keywords.html#strict-keywords
const STRICT: &[&str] = &[
"as", "async", "await", "break", "const", "continue", "crate", "dyn", "else", "enum",
"extern", "false", "fn", "for", "if", "impl", "in", "let", "loop", "match", "mod", "move",
"mut", "pub", "ref", "return", "self", "Self", "static", "struct", "super", "trait",
"true", "type", "unsafe", "use", "where", "while",
];
/// Reserved keywords.
///
/// > These keywords aren't used yet, but they are reserved for future use. They have the same
/// > restrictions as strict keywords. The reasoning behind this is to make current programs
/// > forward compatible with future versions of Rust by forbidding them to use these keywords.
/// >
/// > - <cite>[The Rust Reference][ref]</cite>
///
/// This list also includes keywords that were introduced in the 2018 edition of Rust.
///
/// [ref]: https://doc.rust-lang.org/reference/keywords.html#reserved-keywords
const RESERVED: &[&str] = &[
"abstract", "become", "box", "do", "final", "macro", "override", "priv", "try", "typeof",
"unsized", "virtual", "yield",
];
/// Handle WASI's [`errno::2big`][err] variant.
///
/// This is an unfortunate edge case that must account for when generating `enum` variants.
/// This will only return `Some(_)` if the given witx identifier *is* `2big`, otherwise this
/// function will return `None`.
///
/// This functionality is a short-term fix that keeps WASI working. Instead of expanding these sort of special cases,
/// we should replace this function by having the user provide a mapping of witx identifiers to Rust identifiers in the
/// arguments to the macro.
///
/// [err]: https://github.com/WebAssembly/WASI/blob/master/phases/snapshot/docs.md#-errno-enumu16
pub fn handle_2big_enum_variant(id: &Id) -> Option<Ident> {
if id.as_str() == "2big" {
Some(format_ident!("TooBig"))
} else {
None
}
}
}