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thiserror-nostd-notrait
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Support Option<Backtrace>

This commit is contained in:
David Tolnay 2019-10-12 15:59:21 -07:00
parent 30b1561f65
commit fac0a7aa0d
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GPG Key ID: F9BA143B95FF6D82
1 changed files with 44 additions and 15 deletions
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59
impl/src/expand.rs
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@ -34,8 +34,8 @@ fn impl_struct(input: Struct) -> TokenStream {
}
});
let backtrace_method = input.backtrace_field().map(|backtrace| {
let backtrace = &backtrace.member;
let backtrace_method = input.backtrace_field().map(|backtrace_field| {
let backtrace = &backtrace_field.member;
let body = if let Some(source_field) = input.source_field() {
let source = &source_field.member;
let source_backtrace = if type_is_option(source_field.ty) {
@ -47,18 +47,31 @@ fn impl_struct(input: Struct) -> TokenStream {
self.#source.as_dyn_error().backtrace()
}
};
quote!({
let combinator = if type_is_option(backtrace_field.ty) {
quote! {
#source_backtrace.or(self.#backtrace.as_ref())
}
} else {
quote! {
std::option::Option::Some(#source_backtrace.unwrap_or(&self.#backtrace))
}
};
quote! {
use thiserror::private::AsDynError;
#source_backtrace.unwrap_or(&self.#backtrace)
})
#combinator
}
} else if type_is_option(backtrace_field.ty) {
quote! {
self.#backtrace.as_ref()
}
} else {
quote! {
&self.#backtrace
std::option::Option::Some(&self.#backtrace)
}
};
quote! {
fn backtrace(&self) -> std::option::Option<&std::backtrace::Backtrace> {
std::option::Option::Some(#body)
#body
}
}
});
@ -126,8 +139,10 @@ fn impl_enum(input: Enum) -> TokenStream {
let arms = input.variants.iter().map(|variant| {
let ident = &variant.ident;
match (variant.backtrace_field(), variant.source_field()) {
(Some(backtrace), Some(source_field)) if backtrace.attrs.backtrace.is_none() => {
let backtrace = &backtrace.member;
(Some(backtrace_field), Some(source_field))
if backtrace_field.attrs.backtrace.is_none() =>
{
let backtrace = &backtrace_field.member;
let source = &source_field.member;
let source_backtrace = if type_is_option(source_field.ty) {
quote_spanned! {source.span()=>
@ -138,21 +153,35 @@ fn impl_enum(input: Enum) -> TokenStream {
source.as_dyn_error().backtrace()
}
};
let combinator = if type_is_option(backtrace_field.ty) {
quote! {
#source_backtrace.or(backtrace.as_ref())
}
} else {
quote! {
std::option::Option::Some(#source_backtrace.unwrap_or(backtrace))
}
};
quote! {
#ty::#ident {
#backtrace: backtrace,
#source: source,
..
} => std::option::Option::Some({
} => {
use thiserror::private::AsDynError;
#source_backtrace.unwrap_or(backtrace)
}),
#combinator
}
}
}
(Some(backtrace), _) => {
let backtrace = &backtrace.member;
(Some(backtrace_field), _) => {
let backtrace = &backtrace_field.member;
let body = if type_is_option(backtrace_field.ty) {
quote!(backtrace.as_ref())
} else {
quote!(std::option::Option::Some(backtrace))
};
quote! {
#ty::#ident {#backtrace: backtrace, ..} => std::option::Option::Some(backtrace),
#ty::#ident {#backtrace: backtrace, ..} => #body,
}
}
(None, _) => quote! {