81 lines
2.7 KiB
Rust
81 lines
2.7 KiB
Rust
use proc_macro2::TokenStream;
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use quote::quote;
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use crate::error_transform::ErrorTransform;
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use crate::lifetimes::{anon_lifetime, LifetimeExt};
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use crate::names::Names;
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use witx::Module;
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pub fn passed_by_reference(ty: &witx::Type) -> bool {
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let passed_by = match ty.passed_by() {
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witx::TypePassedBy::Value { .. } => false,
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witx::TypePassedBy::Pointer { .. } | witx::TypePassedBy::PointerLengthPair { .. } => true,
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};
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match ty {
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witx::Type::Builtin(b) => match &*b {
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witx::BuiltinType::String => true,
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_ => passed_by,
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},
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witx::Type::Pointer(_) | witx::Type::ConstPointer(_) | witx::Type::Array(_) => true,
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_ => passed_by,
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}
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}
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pub fn define_module_trait(names: &Names, m: &Module, errxform: &ErrorTransform) -> TokenStream {
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let traitname = names.trait_name(&m.name);
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let traitmethods = m.funcs().map(|f| {
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// Check if we're returning an entity anotated with a lifetime,
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// in which case, we'll need to annotate the function itself, and
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// hence will need an explicit lifetime (rather than anonymous)
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let (lifetime, is_anonymous) = if f
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.params
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.iter()
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.chain(&f.results)
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.any(|ret| ret.tref.needs_lifetime())
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{
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(quote!('a), false)
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} else {
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(anon_lifetime(), true)
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};
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let funcname = names.func(&f.name);
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let args = f.params.iter().map(|arg| {
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let arg_name = names.func_param(&arg.name);
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let arg_typename = names.type_ref(&arg.tref, lifetime.clone());
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let arg_type = if passed_by_reference(&*arg.tref.type_()) {
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quote!(&#arg_typename)
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} else {
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quote!(#arg_typename)
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};
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quote!(#arg_name: #arg_type)
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});
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let rets = f
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.results
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.iter()
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.skip(1)
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.map(|ret| names.type_ref(&ret.tref, lifetime.clone()));
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let err = f
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.results
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.get(0)
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.map(|err_result| {
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if let Some(custom_err) = errxform.for_abi_error(&err_result.tref) {
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let tn = custom_err.typename();
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quote!(super::#tn)
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} else {
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names.type_ref(&err_result.tref, lifetime.clone())
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}
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})
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.unwrap_or(quote!(()));
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if is_anonymous {
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quote!(fn #funcname(&self, #(#args),*) -> Result<(#(#rets),*), #err>;)
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} else {
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quote!(fn #funcname<#lifetime>(&self, #(#args),*) -> Result<(#(#rets),*), #err>;)
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}
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});
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quote! {
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pub trait #traitname {
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#(#traitmethods)*
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}
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}
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}
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