Function wiggle_generate::names::user_error_conversion_method
source · pub fn user_error_conversion_method(user_type: &UserErrorType) -> IdentExamples found in repository?
src/lib.rs (line 43)
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pub fn generate(doc: &witx::Document, settings: &CodegenSettings) -> TokenStream {
let types = doc
.typenames()
.map(|t| define_datatype(&t, settings.errors.for_name(&t)));
let constants = doc.constants().map(|c| {
let name = quote::format_ident!(
"{}_{}",
c.ty.as_str().to_shouty_snake_case(),
c.name.as_str().to_shouty_snake_case()
);
let ty = names::type_(&c.ty);
let value = Literal::u64_unsuffixed(c.value);
quote! {
pub const #name: #ty = #value;
}
});
let user_error_methods = settings.errors.iter().filter_map(|errtype| match errtype {
ErrorType::User(errtype) => {
let abi_typename = names::type_ref(&errtype.abi_type(), anon_lifetime());
let user_typename = errtype.typename();
let methodname = names::user_error_conversion_method(&errtype);
Some(quote! {
fn #methodname(&mut self, e: super::#user_typename)
-> wiggle::anyhow::Result<#abi_typename>;
})
}
ErrorType::Generated(_) => None,
});
let user_error_conversion = quote! {
pub trait UserErrorConversion {
#(#user_error_methods)*
}
};
let modules = doc.modules().map(|module| {
let modname = names::module(&module.name);
let fs = module.funcs().map(|f| define_func(&module, &f, &settings));
let modtrait = define_module_trait(&module, &settings);
let wasmtime = if settings.wasmtime {
crate::wasmtime::link_module(&module, None, &settings)
} else {
quote! {}
};
quote!(
pub mod #modname {
use super::types::*;
pub use super::types::UserErrorConversion;
#(#fs)*
#modtrait
#wasmtime
}
)
});
quote!(
pub mod types {
use std::convert::TryFrom;
#(#types)*
#(#constants)*
#user_error_conversion
}
#(#modules)*
)
}More examples
src/funcs.rs (line 317)
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fn emit(
&mut self,
inst: &Instruction<'_>,
operands: &mut Vec<TokenStream>,
results: &mut Vec<TokenStream>,
) {
let wrap_err = |location: &str| {
let modulename = self.module.name.as_str();
let funcname = self.funcname;
quote! {
|e| {
wiggle::GuestError::InFunc {
modulename: #modulename,
funcname: #funcname,
location: #location,
err: Box::new(wiggle::GuestError::from(e)),
}
}
}
};
let mut try_from = |ty: TokenStream| {
let val = operands.pop().unwrap();
let wrap_err = wrap_err(&format!("convert {}", ty));
results.push(quote!(#ty::try_from(#val).map_err(#wrap_err)?));
};
match inst {
Instruction::GetArg { nth } => {
let param = &self.params[*nth];
results.push(quote!(#param));
}
Instruction::PointerFromI32 { ty } | Instruction::ConstPointerFromI32 { ty } => {
let val = operands.pop().unwrap();
let pointee_type = names::type_ref(ty, anon_lifetime());
results.push(quote! {
wiggle::GuestPtr::<#pointee_type>::new(memory, #val as u32)
});
}
Instruction::ListFromPointerLength { ty } => {
let ptr = &operands[0];
let len = &operands[1];
let ty = match &**ty.type_() {
witx::Type::Builtin(witx::BuiltinType::Char) => quote!(str),
_ => {
let ty = names::type_ref(ty, anon_lifetime());
quote!([#ty])
}
};
results.push(quote! {
wiggle::GuestPtr::<#ty>::new(memory, (#ptr as u32, #len as u32));
})
}
Instruction::CallInterface { func, .. } => {
// Use the `tracing` crate to log all arguments that are going
// out, and afterwards we call the function with those bindings.
let mut args = Vec::new();
for (i, param) in func.params.iter().enumerate() {
let name = names::func_param(¶m.name);
let val = &operands[i];
self.src.extend(quote!(let #name = #val;));
if passed_by_reference(param.tref.type_()) {
args.push(quote!(&#name));
} else {
args.push(quote!(#name));
}
}
if self
.settings
.tracing
.enabled_for(self.module.name.as_str(), self.funcname)
&& func.params.len() > 0
{
let args = func
.params
.iter()
.map(|param| {
let name = names::func_param(¶m.name);
if param.impls_display() {
quote!( #name = wiggle::tracing::field::display(&#name) )
} else {
quote!( #name = wiggle::tracing::field::debug(&#name) )
}
})
.collect::<Vec<_>>();
self.src.extend(quote! {
wiggle::tracing::event!(wiggle::tracing::Level::TRACE, #(#args),*);
});
}
let trait_name = names::trait_name(&self.module.name);
let ident = names::func(&func.name);
if self.settings.get_async(&self.module, &func).is_sync() {
self.src.extend(quote! {
let ret = #trait_name::#ident(ctx, #(#args),*);
})
} else {
self.src.extend(quote! {
let ret = #trait_name::#ident(ctx, #(#args),*).await;
})
};
if self
.settings
.tracing
.enabled_for(self.module.name.as_str(), self.funcname)
{
self.src.extend(quote! {
wiggle::tracing::event!(
wiggle::tracing::Level::TRACE,
result = wiggle::tracing::field::debug(&ret),
);
});
}
if func.results.len() > 0 {
results.push(quote!(ret));
} else if func.noreturn {
self.src.extend(quote!(return Err(ret);));
}
}
// Lowering an enum is typically simple but if we have an error
// transformation registered for this enum then what we're actually
// doing is lowering from a user-defined error type to the error
// enum, and *then* we lower to an i32.
Instruction::EnumLower { ty } => {
let val = operands.pop().unwrap();
let val = match self.settings.errors.for_name(ty) {
Some(ErrorType::User(custom)) => {
let method = names::user_error_conversion_method(&custom);
self.bound(quote::format_ident!("UserErrorConversion"));
quote!(UserErrorConversion::#method(ctx, #val)?)
}
Some(ErrorType::Generated(_)) => quote!(#val.downcast()?),
None => val,
};
results.push(quote!(#val as i32));
}
Instruction::ResultLower { err: err_ty, .. } => {
let err = self.blocks.pop().unwrap();
let ok = self.blocks.pop().unwrap();
let val = operands.pop().unwrap();
let err_typename = names::type_ref(err_ty.unwrap(), anon_lifetime());
results.push(quote! {
match #val {
Ok(e) => { #ok; <#err_typename as wiggle::GuestErrorType>::success() as i32 }
Err(e) => { #err }
}
});
}
Instruction::VariantPayload => results.push(quote!(e)),
Instruction::Return { amt: 0 } => {
self.src.extend(quote!(return Ok(())));
}
Instruction::Return { amt: 1 } => {
let val = operands.pop().unwrap();
self.src.extend(quote!(return Ok(#val)));
}
Instruction::Return { .. } => unimplemented!(),
Instruction::TupleLower { amt } => {
let names = (0..*amt)
.map(|i| Ident::new(&format!("t{}", i), Span::call_site()))
.collect::<Vec<_>>();
let val = operands.pop().unwrap();
self.src.extend(quote!( let (#(#names,)*) = #val;));
results.extend(names.iter().map(|i| quote!(#i)));
}
Instruction::Store { ty } => {
let ptr = operands.pop().unwrap();
let val = operands.pop().unwrap();
let wrap_err = wrap_err(&format!("write {}", ty.name.as_str()));
let pointee_type = names::type_(&ty.name);
self.src.extend(quote! {
wiggle::GuestPtr::<#pointee_type>::new(memory, #ptr as u32)
.write(#val)
.map_err(#wrap_err)?;
});
}
Instruction::Load { ty } => {
let ptr = operands.pop().unwrap();
let wrap_err = wrap_err(&format!("read {}", ty.name.as_str()));
let pointee_type = names::type_(&ty.name);
results.push(quote! {
wiggle::GuestPtr::<#pointee_type>::new(memory, #ptr as u32)
.read()
.map_err(#wrap_err)?
});
}
Instruction::HandleFromI32 { ty } => {
let val = operands.pop().unwrap();
let ty = names::type_(&ty.name);
results.push(quote!(#ty::from(#val)));
}
// Smaller-than-32 numerical conversions are done with `TryFrom` to
// ensure we're not losing bits.
Instruction::U8FromI32 => try_from(quote!(u8)),
Instruction::S8FromI32 => try_from(quote!(i8)),
Instruction::Char8FromI32 => try_from(quote!(u8)),
Instruction::U16FromI32 => try_from(quote!(u16)),
Instruction::S16FromI32 => try_from(quote!(i16)),
// Conversions with matching bit-widths but different signededness
// use `as` since we're basically just reinterpreting the bits.
Instruction::U32FromI32 | Instruction::UsizeFromI32 => {
let val = operands.pop().unwrap();
results.push(quote!(#val as u32));
}
Instruction::U64FromI64 => {
let val = operands.pop().unwrap();
results.push(quote!(#val as u64));
}
// Conversions to enums/bitflags use `TryFrom` to ensure that the
// values are valid coming in.
Instruction::EnumLift { ty }
| Instruction::BitflagsFromI64 { ty }
| Instruction::BitflagsFromI32 { ty } => {
let ty = names::type_(&ty.name);
try_from(quote!(#ty))
}
// No conversions necessary for these, the native wasm type matches
// our own representation.
Instruction::If32FromF32
| Instruction::If64FromF64
| Instruction::S32FromI32
| Instruction::S64FromI64 => results.push(operands.pop().unwrap()),
// There's a number of other instructions we could implement but
// they're not exercised by WASI at this time. As necessary we can
// add code to implement them.
other => panic!("no implementation for {:?}", other),
}
}