feat(macro): support add attributes to source and context fields

loichyan · Jun 18, 2021 · 9c6f050 · 9c6f050
1 parent 9f73de5
commit 9c6f050
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Showing 4 changed files with 31 additions and 1 deletion.
diff --git a/README.md b/README.md
@@ -13,6 +13,7 @@ thisctx! {
     pub enum Error {
         #[error("I/O failed '{}': {src}", .ctx.path.display())]
         IoFaild {
+            #[source]
             @source
             src: std::io::Error,
             @context
@@ -32,8 +33,15 @@ thisctx! {
                     path: std::path::PathBuf,
                 },
         },
+        #[error("not UTF-8: {0}")]
+        NotUtf8 (
+            #[source]
+            @source
+            std::str::Utf8Error
+        ),
         #[error("invalid argument: '{}'", 0.0)]
         InvalidArg (
+            @context
             #[derive(Debug)]
             struct (String)
         ),

diff --git a/impl/src/expand.rs b/impl/src/expand.rs
@@ -162,6 +162,7 @@ impl Variant {
                  name,
                  colon_token,
                  anon_struct,
+                 ..
              }| {
                 let from = quote!(self);
                 let convert_struct_body = anon_struct
@@ -185,6 +186,7 @@ impl Variant {
         )
     }
 
+    // TODO: impl from source for enum
     fn to_impl_from_ctx_for_enum(&self, enum_name: &Ident) -> Option<TokenStream> {
         let Self {
             name: variant_name,
@@ -201,6 +203,7 @@ impl Variant {
                  name,
                  colon_token,
                  anon_struct,
+                 ..
              }| {
                 let convert_struct_body = anon_struct
                     .body
@@ -241,14 +244,15 @@ impl ToTokens for Variant {
         let struct_body = body.map_fields(
             SourceField::to_token_stream,
             |ContextField {
+                 attrs,
                  name,
                  colon_token,
                  anon_struct,
              }| {
                 let generic = anon_struct
                     .body
                     .map_fields_to_generic(StructBody::GENERIC_TY_F);
-                quote!(#name #colon_token #variant_name #generic)
+                quote!(#attrs #name #colon_token #variant_name #generic)
             },
         );
         attrs.to_tokens(tokens);
@@ -334,6 +338,7 @@ impl VariantFields {
         let mut src = None;
         let mut ctx = None;
         Punctuated::<_, Token![,]>::visit_parse_with(input, |input| {
+            let attrs = input.parse()?;
             input.parse::<Token![@]>()?;
             let lookhead = input.lookahead1();
             if lookhead.peek(kw::source) {
@@ -344,6 +349,7 @@ impl VariantFields {
                 let (name, colon_token) = parse_name_colon_token()?;
                 let ty = input.parse()?;
                 src = Some(SourceField {
+                    attrs,
                     name,
                     colon_token,
                     ty,
@@ -356,6 +362,7 @@ impl VariantFields {
                 let (name, colon_token) = parse_name_colon_token()?;
                 let anon_struct = input.parse()?;
                 ctx = Some(ContextField {
+                    attrs,
                     name,
                     colon_token,
                     anon_struct,
@@ -371,6 +378,7 @@ impl VariantFields {
 }
 
 struct SourceField {
+    attrs: Attributes,
     name: Option<Ident>,
     colon_token: Option<Token![:]>,
     ty: Type,
@@ -379,17 +387,20 @@ struct SourceField {
 impl ToTokens for SourceField {
     fn to_tokens(&self, tokens: &mut TokenStream) {
         let Self {
+            attrs,
             name,
             colon_token,
             ty,
         } = self;
+        attrs.to_tokens(tokens);
         name.to_tokens(tokens);
         colon_token.to_tokens(tokens);
         ty.to_tokens(tokens);
     }
 }
 
 struct ContextField {
+    attrs: Attributes,
     name: Option<Ident>,
     colon_token: Option<Token![:]>,
     anon_struct: AnonStruct,

diff --git a/src/ext.rs b/src/ext.rs
@@ -1,6 +1,14 @@
 #[derive(Debug)]
 pub struct NoneError;
 
+impl std::fmt::Display for NoneError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "an placeholder for none source error variant")
+    }
+}
+
+impl std::error::Error for NoneError {}
+
 pub trait IntoError {
     type Error;
     type Source;

diff --git a/tests/use_macro.rs b/tests/use_macro.rs
@@ -6,6 +6,7 @@ thisctx! {
     pub enum Error {
         #[error("I/O failed '{}': {src}", .ctx.path.display())]
         IoFaild {
+            #[source]
             @source
             src: std::io::Error,
             @context
@@ -17,6 +18,7 @@ thisctx! {
         },
         #[error("I/O failed: {src}")]
         IoFaildWithoutPath {
+            #[source]
             @source
             src: std::io::Error,
         },
@@ -38,6 +40,7 @@ thisctx! {
         ),
         #[error("invalid argument: '{}'", 1.0)]
         InvalidArg (
+            #[source]
             @source
             thisctx::NoneError,
             @context