|
| 1 | +use convert_case::{Case, Casing}; |
| 2 | +use proc_macro2::TokenStream; |
| 3 | +use quote::quote; |
| 4 | +use syn::{DeriveInput, FieldsNamed, FieldsUnnamed}; |
| 5 | + |
| 6 | +pub fn derive_tryfromjs_struct(input: &DeriveInput, data: &syn::DataStruct) -> TokenStream { |
| 7 | + let struct_ident = &input.ident; |
| 8 | + let generics = &input.generics; |
| 9 | + let (impl_generics, ty_generics, where_clause) = generics.split_for_impl(); |
| 10 | + |
| 11 | + let field_conversions = if let syn::Fields::Named(ref fields) = data.fields { |
| 12 | + field_conversions_for_named_fields(fields) |
| 13 | + } else { |
| 14 | + panic!("Only named fields are supported") |
| 15 | + }; |
| 16 | + |
| 17 | + let expanded = quote! { |
| 18 | + impl #impl_generics crate::helpers::TryFromJs for #struct_ident #ty_generics #where_clause { |
| 19 | + fn try_from_js<'cx, 'b>(cx: &mut impl neon::prelude::Context<'cx>, js_value: neon::prelude::Handle<'b, neon::prelude::JsValue>) -> crate::helpers::BridgeResult<Self> { |
| 20 | + use crate::helpers::{ObjectExt as _, FunctionContextExt as _, AppendFieldContext as _}; |
| 21 | + |
| 22 | + let obj = js_value.downcast::<neon::prelude::JsObject, _>(cx)?; |
| 23 | + Ok(Self { |
| 24 | + #(#field_conversions),* |
| 25 | + }) |
| 26 | + } |
| 27 | + } |
| 28 | + }; |
| 29 | + |
| 30 | + // eprintln!( |
| 31 | + // "=== struct {} ===\n{}\n======", |
| 32 | + // struct_ident.to_string(), |
| 33 | + // expanded |
| 34 | + // ); |
| 35 | + |
| 36 | + TokenStream::from(expanded) |
| 37 | +} |
| 38 | + |
| 39 | +pub fn derive_tryfromjs_enum(input: &DeriveInput, data: &syn::DataEnum) -> TokenStream { |
| 40 | + let enum_ident = &input.ident; |
| 41 | + let enum_name = enum_ident.to_string(); |
| 42 | + let variants = &data.variants; |
| 43 | + let generics = &input.generics; |
| 44 | + let (impl_generics, ty_generics, where_clause) = generics.split_for_impl(); |
| 45 | + |
| 46 | + let variant_conversions = variants.iter().map(|v| { |
| 47 | + let variant_ident = &v.ident; |
| 48 | + let discriminant = variant_ident.to_string().to_case(Case::Kebab); |
| 49 | + let js_discriminant = variant_ident.to_string().to_case(Case::Camel); |
| 50 | + |
| 51 | + match &v.fields { |
| 52 | + syn::Fields::Unit => { |
| 53 | + // e.g. "otel" => Ok(MetricsExporter::Otel) |
| 54 | + quote! { |
| 55 | + #discriminant => Ok(#enum_ident::#variant_ident), |
| 56 | + } |
| 57 | + } |
| 58 | + syn::Fields::Unnamed(FieldsUnnamed { unnamed, .. }) => { |
| 59 | + if unnamed.len() != 1 { |
| 60 | + panic!("Enum variant must have a single unnamed field that implements the TryFromJs trait"); |
| 61 | + } |
| 62 | + let ty = unnamed.first().map(|f| f.ty.clone()).unwrap(); |
| 63 | + match ty { |
| 64 | + syn::Type::Path(path) => { |
| 65 | + // Example output: |
| 66 | + // |
| 67 | + // "otel" => { |
| 68 | + // <OtelConfig>::try_from_js(cx, js_value).field("otel").map(MetricsExporter::Otel) |
| 69 | + // } |
| 70 | + quote! { |
| 71 | + #discriminant => { |
| 72 | + <#path>::try_from_js(cx, js_value).field(&#js_discriminant).map(#enum_ident::#variant_ident) |
| 73 | + }, |
| 74 | + } |
| 75 | + }, |
| 76 | + _ => panic!("Enum variant must have a single unnamed field that implements the TryFromJs trait"), |
| 77 | + } |
| 78 | + } |
| 79 | + syn::Fields::Named(fields) => { |
| 80 | + // Example output: |
| 81 | + // |
| 82 | + // "console" => Ok((|| { |
| 83 | + // Ok::<LogExporter, BridgeError>(LogExporter::Console { |
| 84 | + // filter: { obj.get_property_into(cx, "filter")? }, |
| 85 | + // }) |
| 86 | + // })() |
| 87 | + // .field(format!("type={}", type_str).as_str())?), |
| 88 | + // |
| 89 | + // The inner closure is required so that we can use the `field` method on the result. |
| 90 | + // An alternative would be to do that at the field level, but then that concern would |
| 91 | + // spill into the field_conversions_for_named_fields function, which is used in |
| 92 | + // other places. |
| 93 | + let field_conversions = field_conversions_for_named_fields(fields); |
| 94 | + quote! { |
| 95 | + #discriminant => Ok(( || { |
| 96 | + Ok::<#enum_ident #ty_generics, crate::helpers::BridgeError>(#enum_ident::#variant_ident { |
| 97 | + #(#field_conversions),* |
| 98 | + }) |
| 99 | + })() |
| 100 | + .field(&#js_discriminant)?), |
| 101 | + } |
| 102 | + } |
| 103 | + } |
| 104 | + }); |
| 105 | + |
| 106 | + let expanded = quote! { |
| 107 | + impl #impl_generics crate::helpers::TryFromJs for #enum_ident #ty_generics #where_clause { |
| 108 | + fn try_from_js<'cx, 'b>(cx: &mut impl neon::prelude::Context<'cx>, js_value: neon::prelude::Handle<'b, neon::prelude::JsValue>) -> crate::helpers::BridgeResult<Self> { |
| 109 | + use crate::helpers::{ObjectExt as _, FunctionContextExt as _, AppendFieldContext as _}; |
| 110 | + |
| 111 | + let obj = js_value.downcast::<neon::prelude::JsObject, _>(cx)?; |
| 112 | + let type_str: String = obj.get_property_into(cx, "type")?; |
| 113 | + |
| 114 | + match type_str.as_str() { |
| 115 | + #(#variant_conversions)* |
| 116 | + _ => Err(crate::helpers::BridgeError::InvalidVariant { |
| 117 | + enum_name: #enum_name.to_string(), |
| 118 | + variant: type_str, |
| 119 | + }), |
| 120 | + } |
| 121 | + } |
| 122 | + } |
| 123 | + }; |
| 124 | + |
| 125 | + // eprintln!( |
| 126 | + // "=== enum {} ===\n{}\n======", |
| 127 | + // enum_ident.to_string(), |
| 128 | + // expanded |
| 129 | + // ); |
| 130 | + |
| 131 | + TokenStream::from(expanded) |
| 132 | +} |
| 133 | + |
| 134 | +fn field_conversions_for_named_fields( |
| 135 | + fields: &FieldsNamed, |
| 136 | +) -> impl Iterator<Item = TokenStream> + '_ { |
| 137 | + fields.named.iter().map(|f| { |
| 138 | + let field_ident = f |
| 139 | + .ident |
| 140 | + .as_ref() |
| 141 | + .expect("FieldsNamed.named must have an identifier"); |
| 142 | + let js_name = field_ident.to_string().to_case(Case::Camel); |
| 143 | + |
| 144 | + quote! { |
| 145 | + #field_ident: { |
| 146 | + obj.get_property_into(cx, #js_name)? |
| 147 | + } |
| 148 | + } |
| 149 | + }) |
| 150 | +} |
0 commit comments