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codegen.rs
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codegen.rs
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use crate::ast;
use crate::encode;
use crate::util::ShortHash;
use crate::Diagnostic;
use proc_macro2::{Ident, Literal, Span, TokenStream};
use quote::{quote, ToTokens};
use std::collections::HashSet;
use std::sync::atomic::{AtomicUsize, Ordering};
use std::sync::Mutex;
use syn;
use wasm_bindgen_shared as shared;
pub trait TryToTokens {
fn try_to_tokens(&self, tokens: &mut TokenStream) -> Result<(), Diagnostic>;
fn try_to_token_stream(&self) -> Result<TokenStream, Diagnostic> {
let mut tokens = TokenStream::new();
self.try_to_tokens(&mut tokens)?;
Ok(tokens)
}
}
impl TryToTokens for ast::Program {
// Generate wrappers for all the items that we've found
fn try_to_tokens(&self, tokens: &mut TokenStream) -> Result<(), Diagnostic> {
let mut errors = Vec::new();
for export in self.exports.iter() {
if let Err(e) = export.try_to_tokens(tokens) {
errors.push(e);
}
}
for s in self.structs.iter() {
s.to_tokens(tokens);
}
let mut types = HashSet::new();
for i in self.imports.iter() {
if let ast::ImportKind::Type(t) = &i.kind {
types.insert(t.rust_name.clone());
}
}
for i in self.imports.iter() {
DescribeImport(&i.kind).to_tokens(tokens);
// If there is a js namespace, check that name isn't a type. If it is,
// this import might be a method on that type.
if let Some(ns) = &i.js_namespace {
if types.contains(ns) && i.kind.fits_on_impl() {
let kind = match i.kind.try_to_token_stream() {
Ok(kind) => kind,
Err(e) => {
errors.push(e);
continue;
}
};
(quote! { impl #ns { #kind } }).to_tokens(tokens);
continue;
}
}
if let Err(e) = i.kind.try_to_tokens(tokens) {
errors.push(e);
}
}
for e in self.enums.iter() {
e.to_tokens(tokens);
}
for c in self.consts.iter() {
c.to_tokens(tokens);
}
for d in self.dictionaries.iter() {
d.to_tokens(tokens);
}
Diagnostic::from_vec(errors)?;
// Generate a static which will eventually be what lives in a custom section
// of the wasm executable. For now it's just a plain old static, but we'll
// eventually have it actually in its own section.
static CNT: AtomicUsize = AtomicUsize::new(0);
let generated_static_name = format!(
"__WASM_BINDGEN_GENERATED_{}",
ShortHash(CNT.fetch_add(1, Ordering::SeqCst)),
);
let generated_static_name = Ident::new(&generated_static_name, Span::call_site());
// See comments in `crates/cli-support/src/lib.rs` about what this
// `schema_version` is.
let prefix_json = format!(
r#"{{"schema_version":"{}","version":"{}"}}"#,
shared::SCHEMA_VERSION,
shared::version()
);
let encoded = encode::encode(self)?;
let mut bytes = Vec::new();
bytes.push((prefix_json.len() >> 0) as u8);
bytes.push((prefix_json.len() >> 8) as u8);
bytes.push((prefix_json.len() >> 16) as u8);
bytes.push((prefix_json.len() >> 24) as u8);
bytes.extend_from_slice(prefix_json.as_bytes());
bytes.extend_from_slice(&encoded.custom_section);
let generated_static_length = bytes.len();
let generated_static_value = syn::LitByteStr::new(&bytes, Span::call_site());
// We already consumed the contents of included files when generating
// the custom section, but we want to make sure that updates to the
// generated files will cause this macro to rerun incrementally. To do
// that we use `include_str!` to force rustc to think it has a
// dependency on these files. That way when the file changes Cargo will
// automatically rerun rustc which will rerun this macro. Other than
// this we don't actually need the results of the `include_str!`, so
// it's just shoved into an anonymous static.
let file_dependencies = encoded.included_files.iter().map(|file| {
let file = file.to_str().unwrap();
quote! { include_str!(#file) }
});
(quote! {
#[allow(non_upper_case_globals)]
#[cfg(target_arch = "wasm32")]
#[link_section = "__wasm_bindgen_unstable"]
#[doc(hidden)]
#[allow(clippy::all)]
pub static #generated_static_name: [u8; #generated_static_length] = {
static _INCLUDED_FILES: &[&str] = &[#(#file_dependencies),*];
*#generated_static_value
};
})
.to_tokens(tokens);
Ok(())
}
}
impl ToTokens for ast::Struct {
fn to_tokens(&self, tokens: &mut TokenStream) {
let name = &self.rust_name;
let name_str = self.js_name.to_string();
let name_len = name_str.len() as u32;
let name_chars = name_str.chars().map(|c| c as u32);
let new_fn = Ident::new(&shared::new_function(&name_str), Span::call_site());
let free_fn = Ident::new(&shared::free_function(&name_str), Span::call_site());
(quote! {
#[allow(clippy::all)]
impl wasm_bindgen::describe::WasmDescribe for #name {
fn describe() {
use wasm_bindgen::__wbindgen_if_not_std;
__wbindgen_if_not_std! {
compile_error! {
"exporting a class to JS requires the `std` feature to \
be enabled in the `wasm-bindgen` crate"
}
}
use wasm_bindgen::describe::*;
inform(RUST_STRUCT);
inform(#name_len);
#(inform(#name_chars);)*
}
}
#[allow(clippy::all)]
impl wasm_bindgen::convert::IntoWasmAbi for #name {
type Abi = u32;
fn into_abi(self) -> u32 {
use wasm_bindgen::__rt::std::boxed::Box;
use wasm_bindgen::__rt::WasmRefCell;
Box::into_raw(Box::new(WasmRefCell::new(self))) as u32
}
}
#[allow(clippy::all)]
impl wasm_bindgen::convert::FromWasmAbi for #name {
type Abi = u32;
unsafe fn from_abi(js: u32) -> Self {
use wasm_bindgen::__rt::std::boxed::Box;
use wasm_bindgen::__rt::{assert_not_null, WasmRefCell};
let ptr = js as *mut WasmRefCell<#name>;
assert_not_null(ptr);
let js = Box::from_raw(ptr);
(*js).borrow_mut(); // make sure no one's borrowing
js.into_inner()
}
}
#[allow(clippy::all)]
impl wasm_bindgen::__rt::core::convert::From<#name> for
wasm_bindgen::JsValue
{
fn from(value: #name) -> Self {
let ptr = wasm_bindgen::convert::IntoWasmAbi::into_abi(value);
#[link(wasm_import_module = "__wbindgen_placeholder__")]
#[cfg(all(target_arch = "wasm32", not(target_os = "emscripten")))]
extern "C" {
fn #new_fn(ptr: u32) -> u32;
}
#[cfg(not(all(target_arch = "wasm32", not(target_os = "emscripten"))))]
unsafe fn #new_fn(_: u32) -> u32 {
panic!("cannot convert to JsValue outside of the wasm target")
}
unsafe {
<wasm_bindgen::JsValue as wasm_bindgen::convert::FromWasmAbi>
::from_abi(#new_fn(ptr))
}
}
}
#[cfg(all(target_arch = "wasm32", not(target_os = "emscripten")))]
#[no_mangle]
#[doc(hidden)]
#[allow(clippy::all)]
pub unsafe extern "C" fn #free_fn(ptr: u32) {
<#name as wasm_bindgen::convert::FromWasmAbi>::from_abi(ptr);
}
#[allow(clippy::all)]
impl wasm_bindgen::convert::RefFromWasmAbi for #name {
type Abi = u32;
type Anchor = wasm_bindgen::__rt::Ref<'static, #name>;
unsafe fn ref_from_abi(js: Self::Abi) -> Self::Anchor {
let js = js as *mut wasm_bindgen::__rt::WasmRefCell<#name>;
wasm_bindgen::__rt::assert_not_null(js);
(*js).borrow()
}
}
#[allow(clippy::all)]
impl wasm_bindgen::convert::RefMutFromWasmAbi for #name {
type Abi = u32;
type Anchor = wasm_bindgen::__rt::RefMut<'static, #name>;
unsafe fn ref_mut_from_abi(js: Self::Abi) -> Self::Anchor {
let js = js as *mut wasm_bindgen::__rt::WasmRefCell<#name>;
wasm_bindgen::__rt::assert_not_null(js);
(*js).borrow_mut()
}
}
impl wasm_bindgen::convert::OptionIntoWasmAbi for #name {
#[inline]
fn none() -> Self::Abi { 0 }
}
impl wasm_bindgen::convert::OptionFromWasmAbi for #name {
#[inline]
fn is_none(abi: &Self::Abi) -> bool { *abi == 0 }
}
})
.to_tokens(tokens);
for field in self.fields.iter() {
field.to_tokens(tokens);
}
}
}
impl ToTokens for ast::StructField {
fn to_tokens(&self, tokens: &mut TokenStream) {
let name = &self.name;
let struct_name = &self.struct_name;
let ty = &self.ty;
let getter = &self.getter;
let setter = &self.setter;
let assert_copy = quote! { assert_copy::<#ty>() };
let assert_copy = respan(assert_copy, ty);
(quote! {
#[doc(hidden)]
#[allow(clippy::all)]
#[cfg_attr(all(target_arch = "wasm32", not(target_os = "emscripten")), no_mangle)]
pub unsafe extern "C" fn #getter(js: u32)
-> <#ty as wasm_bindgen::convert::IntoWasmAbi>::Abi
{
use wasm_bindgen::__rt::{WasmRefCell, assert_not_null};
use wasm_bindgen::convert::IntoWasmAbi;
fn assert_copy<T: Copy>(){}
#assert_copy;
let js = js as *mut WasmRefCell<#struct_name>;
assert_not_null(js);
let val = (*js).borrow().#name;
<#ty as IntoWasmAbi>::into_abi(val)
}
})
.to_tokens(tokens);
Descriptor(
&getter,
quote! {
<#ty as WasmDescribe>::describe();
},
)
.to_tokens(tokens);
if self.readonly {
return;
}
(quote! {
#[no_mangle]
#[doc(hidden)]
#[cfg(all(target_arch = "wasm32", not(target_os = "emscripten")))]
#[allow(clippy::all)]
pub unsafe extern "C" fn #setter(
js: u32,
val: <#ty as wasm_bindgen::convert::FromWasmAbi>::Abi,
) {
use wasm_bindgen::__rt::{WasmRefCell, assert_not_null};
use wasm_bindgen::convert::FromWasmAbi;
let js = js as *mut WasmRefCell<#struct_name>;
assert_not_null(js);
let val = <#ty as FromWasmAbi>::from_abi(val);
(*js).borrow_mut().#name = val;
}
})
.to_tokens(tokens);
}
}
impl TryToTokens for ast::Export {
fn try_to_tokens(self: &ast::Export, into: &mut TokenStream) -> Result<(), Diagnostic> {
let generated_name = self.rust_symbol();
let export_name = self.export_name();
let mut args = vec![];
let mut arg_conversions = vec![];
let mut converted_arguments = vec![];
let ret = Ident::new("_ret", Span::call_site());
let offset = if self.method_self.is_some() {
args.push(quote! { me: u32 });
1
} else {
0
};
let name = &self.rust_name;
let receiver = match self.method_self {
Some(ast::MethodSelf::ByValue) => {
let class = self.rust_class.as_ref().unwrap();
arg_conversions.push(quote! {
let me = unsafe {
<#class as wasm_bindgen::convert::FromWasmAbi>::from_abi(me)
};
});
quote! { me.#name }
}
Some(ast::MethodSelf::RefMutable) => {
let class = self.rust_class.as_ref().unwrap();
arg_conversions.push(quote! {
let mut me = unsafe {
<#class as wasm_bindgen::convert::RefMutFromWasmAbi>
::ref_mut_from_abi(me)
};
let me = &mut *me;
});
quote! { me.#name }
}
Some(ast::MethodSelf::RefShared) => {
let class = self.rust_class.as_ref().unwrap();
arg_conversions.push(quote! {
let me = unsafe {
<#class as wasm_bindgen::convert::RefFromWasmAbi>
::ref_from_abi(me)
};
let me = &*me;
});
quote! { me.#name }
}
None => match &self.rust_class {
Some(class) => quote! { #class::#name },
None => quote! { #name },
},
};
let mut argtys = Vec::new();
for (i, arg) in self.function.arguments.iter().enumerate() {
argtys.push(&arg.ty);
let i = i + offset;
let ident = Ident::new(&format!("arg{}", i), Span::call_site());
let ty = &arg.ty;
match &*arg.ty {
syn::Type::Reference(syn::TypeReference {
mutability: Some(_),
elem,
..
}) => {
args.push(quote! {
#ident: <#elem as wasm_bindgen::convert::RefMutFromWasmAbi>::Abi
});
arg_conversions.push(quote! {
let mut #ident = unsafe {
<#elem as wasm_bindgen::convert::RefMutFromWasmAbi>
::ref_mut_from_abi(#ident)
};
let #ident = &mut *#ident;
});
}
syn::Type::Reference(syn::TypeReference { elem, .. }) => {
args.push(quote! {
#ident: <#elem as wasm_bindgen::convert::RefFromWasmAbi>::Abi
});
arg_conversions.push(quote! {
let #ident = unsafe {
<#elem as wasm_bindgen::convert::RefFromWasmAbi>
::ref_from_abi(#ident)
};
let #ident = &*#ident;
});
}
_ => {
args.push(quote! {
#ident: <#ty as wasm_bindgen::convert::FromWasmAbi>::Abi
});
arg_conversions.push(quote! {
let #ident = unsafe {
<#ty as wasm_bindgen::convert::FromWasmAbi>
::from_abi(#ident)
};
});
}
}
converted_arguments.push(quote! { #ident });
}
let syn_unit = syn::Type::Tuple(syn::TypeTuple {
elems: Default::default(),
paren_token: Default::default(),
});
let syn_ret = self.function.ret.as_ref().unwrap_or(&syn_unit);
if let syn::Type::Reference(_) = syn_ret {
bail_span!(syn_ret, "cannot return a borrowed ref with #[wasm_bindgen]",)
}
// For an `async` function we always run it through `future_to_promise`
// since we're returning a promise to JS, and this will implicitly
// require that the function returns a `Future<Output = Result<...>>`
let (ret_ty, ret_expr) = if self.function.r#async {
(
quote! { wasm_bindgen::JsValue },
quote! {
wasm_bindgen_futures::future_to_promise(async {
wasm_bindgen::__rt::IntoJsResult::into_js_result(#ret.await)
}).into()
},
)
} else {
(
quote! { #syn_ret },
quote! { #ret },
)
};
let projection = quote! { <#ret_ty as wasm_bindgen::convert::ReturnWasmAbi> };
let convert_ret = quote! { #projection::return_abi(#ret_expr) };
let describe_ret = quote! {
<#ret_ty as WasmDescribe>::describe();
};
let nargs = self.function.arguments.len() as u32;
let attrs = &self.function.rust_attrs;
let start_check = if self.start {
quote! { const _ASSERT: fn() = || -> #projection::Abi { loop {} }; }
} else {
quote! {}
};
(quote! {
#(#attrs)*
#[allow(non_snake_case)]
#[cfg_attr(
all(target_arch = "wasm32", not(target_os = "emscripten")),
export_name = #export_name,
)]
#[allow(clippy::all)]
pub extern "C" fn #generated_name(#(#args),*) -> #projection::Abi {
#start_check
// Scope all local variables to be destroyed after we call the
// function to ensure that `#convert_ret`, if it panics, doesn't
// leak anything.
let #ret = {
#(#arg_conversions)*
#receiver(#(#converted_arguments),*)
};
#convert_ret
}
})
.to_tokens(into);
// In addition to generating the shim function above which is what
// our generated JS will invoke, we *also* generate a "descriptor"
// shim. This descriptor shim uses the `WasmDescribe` trait to
// programmatically describe the type signature of the generated
// shim above. This in turn is then used to inform the
// `wasm-bindgen` CLI tool exactly what types and such it should be
// using in JS.
//
// Note that this descriptor function is a purely an internal detail
// of `#[wasm_bindgen]` and isn't intended to be exported to anyone
// or actually part of the final was binary. Additionally, this is
// literally executed when the `wasm-bindgen` tool executes.
//
// In any case, there's complications in `wasm-bindgen` to handle
// this, but the tl;dr; is that this is stripped from the final wasm
// binary along with anything it references.
let export = Ident::new(&export_name, Span::call_site());
Descriptor(
&export,
quote! {
inform(FUNCTION);
inform(0);
inform(#nargs);
#(<#argtys as WasmDescribe>::describe();)*
#describe_ret
},
)
.to_tokens(into);
Ok(())
}
}
impl TryToTokens for ast::ImportKind {
fn try_to_tokens(&self, tokens: &mut TokenStream) -> Result<(), Diagnostic> {
match *self {
ast::ImportKind::Function(ref f) => f.try_to_tokens(tokens)?,
ast::ImportKind::Static(ref s) => s.to_tokens(tokens),
ast::ImportKind::Type(ref t) => t.to_tokens(tokens),
ast::ImportKind::Enum(ref e) => e.to_tokens(tokens),
}
Ok(())
}
}
impl ToTokens for ast::ImportType {
fn to_tokens(&self, tokens: &mut TokenStream) {
let vis = &self.vis;
let rust_name = &self.rust_name;
let attrs = &self.attrs;
let doc_comment = match &self.doc_comment {
None => "",
Some(comment) => comment,
};
let const_name = format!("__wbg_generated_const_{}", rust_name);
let const_name = Ident::new(&const_name, Span::call_site());
let instanceof_shim = Ident::new(&self.instanceof_shim, Span::call_site());
let internal_obj = match self.extends.first() {
Some(target) => {
quote! { #target }
}
None => {
quote! { wasm_bindgen::JsValue }
}
};
let is_type_of = self.is_type_of.as_ref().map(|is_type_of| {
quote! {
#[inline]
fn is_type_of(val: &JsValue) -> bool {
let is_type_of: fn(&JsValue) -> bool = #is_type_of;
is_type_of(val)
}
}
});
(quote! {
#[allow(bad_style)]
#(#attrs)*
#[doc = #doc_comment]
#[repr(transparent)]
#[allow(clippy::all)]
#vis struct #rust_name {
obj: #internal_obj
}
#[allow(bad_style)]
#[allow(clippy::all)]
const #const_name: () = {
use wasm_bindgen::convert::{IntoWasmAbi, FromWasmAbi};
use wasm_bindgen::convert::{OptionIntoWasmAbi, OptionFromWasmAbi};
use wasm_bindgen::convert::RefFromWasmAbi;
use wasm_bindgen::describe::WasmDescribe;
use wasm_bindgen::{JsValue, JsCast};
use wasm_bindgen::__rt::core;
impl WasmDescribe for #rust_name {
fn describe() {
JsValue::describe();
}
}
impl core::ops::Deref for #rust_name {
type Target = #internal_obj;
#[inline]
fn deref(&self) -> &#internal_obj {
&self.obj
}
}
impl IntoWasmAbi for #rust_name {
type Abi = <JsValue as IntoWasmAbi>::Abi;
#[inline]
fn into_abi(self) -> Self::Abi {
self.obj.into_abi()
}
}
impl OptionIntoWasmAbi for #rust_name {
#[inline]
fn none() -> Self::Abi { 0 }
}
impl<'a> OptionIntoWasmAbi for &'a #rust_name {
#[inline]
fn none() -> Self::Abi { 0 }
}
impl FromWasmAbi for #rust_name {
type Abi = <JsValue as FromWasmAbi>::Abi;
#[inline]
unsafe fn from_abi(js: Self::Abi) -> Self {
#rust_name {
obj: JsValue::from_abi(js).into(),
}
}
}
impl OptionFromWasmAbi for #rust_name {
#[inline]
fn is_none(abi: &Self::Abi) -> bool { *abi == 0 }
}
impl<'a> IntoWasmAbi for &'a #rust_name {
type Abi = <&'a JsValue as IntoWasmAbi>::Abi;
#[inline]
fn into_abi(self) -> Self::Abi {
(&self.obj).into_abi()
}
}
impl RefFromWasmAbi for #rust_name {
type Abi = <JsValue as RefFromWasmAbi>::Abi;
type Anchor = core::mem::ManuallyDrop<#rust_name>;
#[inline]
unsafe fn ref_from_abi(js: Self::Abi) -> Self::Anchor {
let tmp = <JsValue as RefFromWasmAbi>::ref_from_abi(js);
core::mem::ManuallyDrop::new(#rust_name {
obj: core::mem::ManuallyDrop::into_inner(tmp).into(),
})
}
}
// TODO: remove this on the next major version
impl From<JsValue> for #rust_name {
#[inline]
fn from(obj: JsValue) -> #rust_name {
#rust_name { obj: obj.into() }
}
}
impl AsRef<JsValue> for #rust_name {
#[inline]
fn as_ref(&self) -> &JsValue { self.obj.as_ref() }
}
impl AsRef<#rust_name> for #rust_name {
#[inline]
fn as_ref(&self) -> &#rust_name { self }
}
impl From<#rust_name> for JsValue {
#[inline]
fn from(obj: #rust_name) -> JsValue {
obj.obj.into()
}
}
impl JsCast for #rust_name {
fn instanceof(val: &JsValue) -> bool {
#[link(wasm_import_module = "__wbindgen_placeholder__")]
#[cfg(all(target_arch = "wasm32", not(target_os = "emscripten")))]
extern "C" {
fn #instanceof_shim(val: u32) -> u32;
}
#[cfg(not(all(target_arch = "wasm32", not(target_os = "emscripten"))))]
unsafe fn #instanceof_shim(_: u32) -> u32 {
panic!("cannot check instanceof on non-wasm targets");
}
unsafe {
let idx = val.into_abi();
#instanceof_shim(idx) != 0
}
}
#is_type_of
#[inline]
fn unchecked_from_js(val: JsValue) -> Self {
#rust_name { obj: val.into() }
}
#[inline]
fn unchecked_from_js_ref(val: &JsValue) -> &Self {
// Should be safe because `#rust_name` is a transparent
// wrapper around `val`
unsafe { &*(val as *const JsValue as *const #rust_name) }
}
}
()
};
})
.to_tokens(tokens);
for superclass in self.extends.iter() {
(quote! {
#[allow(clippy::all)]
impl From<#rust_name> for #superclass {
#[inline]
fn from(obj: #rust_name) -> #superclass {
use wasm_bindgen::JsCast;
#superclass::unchecked_from_js(obj.into())
}
}
#[allow(clippy::all)]
impl AsRef<#superclass> for #rust_name {
#[inline]
fn as_ref(&self) -> &#superclass {
use wasm_bindgen::JsCast;
#superclass::unchecked_from_js_ref(self.as_ref())
}
}
})
.to_tokens(tokens);
}
}
}
impl ToTokens for ast::ImportEnum {
fn to_tokens(&self, tokens: &mut TokenStream) {
let vis = &self.vis;
let name = &self.name;
let expect_string = format!("attempted to convert invalid {} into JSValue", name);
let variants = &self.variants;
let variant_strings = &self.variant_values;
let attrs = &self.rust_attrs;
let mut current_idx: usize = 0;
let variant_indexes: Vec<Literal> = variants
.iter()
.map(|_| {
let this_index = current_idx;
current_idx += 1;
Literal::usize_unsuffixed(this_index)
})
.collect();
// Borrow variant_indexes because we need to use it multiple times inside the quote! macro
let variant_indexes_ref = &variant_indexes;
// A vector of EnumName::VariantName tokens for this enum
let variant_paths: Vec<TokenStream> = self
.variants
.iter()
.map(|v| quote!(#name::#v).into_token_stream())
.collect();
// Borrow variant_paths because we need to use it multiple times inside the quote! macro
let variant_paths_ref = &variant_paths;
(quote! {
#[allow(bad_style)]
#(#attrs)*
#[allow(clippy::all)]
#vis enum #name {
#(#variants = #variant_indexes_ref,)*
#[doc(hidden)]
__Nonexhaustive,
}
#[allow(clippy::all)]
impl #name {
#vis fn from_js_value(obj: &wasm_bindgen::JsValue) -> Option<#name> {
obj.as_string().and_then(|obj_str| match obj_str.as_str() {
#(#variant_strings => Some(#variant_paths_ref),)*
_ => None,
})
}
}
#[allow(clippy::all)]
impl wasm_bindgen::describe::WasmDescribe for #name {
fn describe() {
wasm_bindgen::JsValue::describe()
}
}
#[allow(clippy::all)]
impl wasm_bindgen::convert::IntoWasmAbi for #name {
type Abi = <wasm_bindgen::JsValue as
wasm_bindgen::convert::IntoWasmAbi>::Abi;
#[inline]
fn into_abi(self) -> Self::Abi {
wasm_bindgen::JsValue::from(self).into_abi()
}
}
#[allow(clippy::all)]
impl wasm_bindgen::convert::FromWasmAbi for #name {
type Abi = <wasm_bindgen::JsValue as
wasm_bindgen::convert::FromWasmAbi>::Abi;
unsafe fn from_abi(js: Self::Abi) -> Self {
#name::from_js_value(&wasm_bindgen::JsValue::from_abi(js)).unwrap_or(#name::__Nonexhaustive)
}
}
#[allow(clippy::all)]
impl wasm_bindgen::convert::OptionIntoWasmAbi for #name {
#[inline]
fn none() -> Self::Abi { Object::none() }
}
#[allow(clippy::all)]
impl wasm_bindgen::convert::OptionFromWasmAbi for #name {
#[inline]
fn is_none(abi: &Self::Abi) -> bool { Object::is_none(abi) }
}
#[allow(clippy::all)]
impl From<#name> for wasm_bindgen::JsValue {
fn from(obj: #name) -> wasm_bindgen::JsValue {
match obj {
#(#variant_paths_ref => wasm_bindgen::JsValue::from_str(#variant_strings),)*
#name::__Nonexhaustive => panic!(#expect_string),
}
}
}
}).to_tokens(tokens);
}
}
impl TryToTokens for ast::ImportFunction {
fn try_to_tokens(&self, tokens: &mut TokenStream) -> Result<(), Diagnostic> {
let mut class_ty = None;
let mut is_method = false;
match self.kind {
ast::ImportFunctionKind::Method {
ref ty, ref kind, ..
} => {
if let ast::MethodKind::Operation(ast::Operation {
is_static: false, ..
}) = kind
{
is_method = true;
}
class_ty = Some(ty);
}
ast::ImportFunctionKind::Normal => {}
}
let vis = &self.function.rust_vis;
let ret = match &self.function.ret {
Some(ty) => quote! { -> #ty },
None => quote!(),
};
let mut abi_argument_names = Vec::new();
let mut abi_arguments = Vec::new();
let mut arg_conversions = Vec::new();
let mut arguments = Vec::new();
let ret_ident = Ident::new("_ret", Span::call_site());
for (i, arg) in self.function.arguments.iter().enumerate() {
let ty = &arg.ty;
let name = match &*arg.pat {
syn::Pat::Ident(syn::PatIdent {
by_ref: None,
ident,
subpat: None,
..
}) => ident.clone(),
syn::Pat::Wild(_) => syn::Ident::new(&format!("__genarg_{}", i), Span::call_site()),
_ => bail_span!(
arg.pat,
"unsupported pattern in #[wasm_bindgen] imported function",
),
};
abi_argument_names.push(name.clone());
abi_arguments.push(quote! {
#name: <#ty as wasm_bindgen::convert::IntoWasmAbi>::Abi
});
let var = if i == 0 && is_method {
quote! { self }
} else {
arguments.push(quote! { #name: #ty });
quote! { #name }
};
arg_conversions.push(quote! {
let #name = <#ty as wasm_bindgen::convert::IntoWasmAbi>
::into_abi(#var);
});
}
let abi_ret;
let mut convert_ret;
match &self.js_ret {
Some(syn::Type::Reference(_)) => {
bail_span!(
self.js_ret,
"cannot return references in #[wasm_bindgen] imports yet"
);
}
Some(ref ty) => {
abi_ret = quote! {
<#ty as wasm_bindgen::convert::FromWasmAbi>::Abi
};
convert_ret = quote! {
<#ty as wasm_bindgen::convert::FromWasmAbi>
::from_abi(#ret_ident)
};
}
None => {
abi_ret = quote! { () };
convert_ret = quote! { () };
}
}
let mut exceptional_ret = quote!();
if self.catch {
convert_ret = quote! { Ok(#convert_ret) };
exceptional_ret = quote! {
wasm_bindgen::__rt::take_last_exception()?;
};
}
let rust_name = &self.rust_name;
let import_name = &self.shim;
let attrs = &self.function.rust_attrs;
let arguments = &arguments;
let abi_arguments = &abi_arguments;
let abi_argument_names = &abi_argument_names;
let doc_comment = match &self.doc_comment {
None => "",
Some(doc_string) => doc_string,
};
let me = if is_method {
quote! { &self, }
} else {
quote!()
};
// Route any errors pointing to this imported function to the identifier
// of the function we're imported from so we at least know what function
// is causing issues.
//
// Note that this is where type errors like "doesn't implement
// FromWasmAbi" or "doesn't implement IntoWasmAbi" currently get routed.
// I suspect that's because they show up in the signature via trait
// projections as types of arguments, and all that needs to typecheck
// before the body can be typechecked. Due to rust-lang/rust#60980 (and
// probably related issues) we can't really get a precise span.
//
// Ideally what we want is to point errors for particular types back to
// the specific argument/type that generated the error, but it looks
// like rustc itself doesn't do great in that regard so let's just do
// the best we can in the meantime.
let extern_fn = respan(
quote! {
#[link(wasm_import_module = "__wbindgen_placeholder__")]
#[cfg(all(target_arch = "wasm32", not(target_os = "emscripten")))]
extern "C" {
fn #import_name(#(#abi_arguments),*) -> #abi_ret;
}
#[cfg(not(all(target_arch = "wasm32", not(target_os = "emscripten"))))]
unsafe fn #import_name(#(#abi_arguments),*) -> #abi_ret {
#(
drop(#abi_argument_names);
)*
panic!("cannot call wasm-bindgen imported functions on \