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| 1 | +use syn::DeriveInput; |
| 2 | +use syn::Meta; |
| 3 | + |
| 4 | +use crate::symbol::OTHER; |
| 5 | +use crate::symbol::{MAP, RENAME}; |
| 6 | +use crate::utils::get_array_lit_str; |
| 7 | +use crate::utils::get_lit_str; |
| 8 | +use crate::utils::get_xmlserde_meta_items; |
| 9 | + |
| 10 | +pub fn get_enum_value_impl_block(input: DeriveInput) -> proc_macro2::TokenStream { |
| 11 | + let data = match input.data { |
| 12 | + syn::Data::Enum(e) => e, |
| 13 | + _ => panic!("expect enum type"), |
| 14 | + }; |
| 15 | + let ident = input.ident; |
| 16 | + let (impl_generics, type_generics, where_clause) = input.generics.split_for_impl(); |
| 17 | + let variants = data |
| 18 | + .variants |
| 19 | + .iter() |
| 20 | + .filter_map(|v| EnumValueVariant::from_variant(v)) |
| 21 | + .collect::<Vec<_>>(); |
| 22 | + |
| 23 | + let ser_branches = variants.iter().map(get_ser_branch).collect::<Vec<_>>(); |
| 24 | + let de_branches = variants.iter().map(get_de_branch).collect::<Vec<_>>(); |
| 25 | + quote! { |
| 26 | + impl #impl_generics ::xmlserde::XmlValue for #ident #type_generics #where_clause { |
| 27 | + fn serialize(&self) -> String { |
| 28 | + match &self { |
| 29 | + #(#ser_branches),* |
| 30 | + } |
| 31 | + } |
| 32 | + fn deserialize(s: &str) -> Result<Self, String> { |
| 33 | + match s { |
| 34 | + #(#de_branches),* |
| 35 | + } |
| 36 | + } |
| 37 | + } |
| 38 | + } |
| 39 | +} |
| 40 | + |
| 41 | +fn get_de_branch(var: &EnumValueVariant) -> proc_macro2::TokenStream { |
| 42 | + let ident = var.ident; |
| 43 | + if var.is_other { |
| 44 | + if let Some(field) = &var.is_other_field { |
| 45 | + let ty = &field.ty; |
| 46 | + return quote! { |
| 47 | + _ => Ok(Self::#ident(#ty::deserialize(s)?)) |
| 48 | + }; |
| 49 | + } |
| 50 | + } |
| 51 | + if !var.map.is_empty() { |
| 52 | + let values = var.map.iter().map(|s| quote! {#s => Ok(Self::#ident)}); |
| 53 | + return quote! { |
| 54 | + #(#values),* |
| 55 | + }; |
| 56 | + } |
| 57 | + if let Some(rename) = &var.rename { |
| 58 | + return quote! { |
| 59 | + #rename => Ok(Self::#ident) |
| 60 | + }; |
| 61 | + } |
| 62 | + panic!("unexpected situation") |
| 63 | +} |
| 64 | + |
| 65 | +fn get_ser_branch(var: &EnumValueVariant) -> proc_macro2::TokenStream { |
| 66 | + let ident = var.ident; |
| 67 | + if var.is_other { |
| 68 | + if let Some(field) = &var.is_other_field { |
| 69 | + let ty = &field.ty; |
| 70 | + return quote! { |
| 71 | + Self::#ident(v) => { |
| 72 | + <#ty as ::xmlserde::XmlValue>::serialize(v) |
| 73 | + } |
| 74 | + }; |
| 75 | + } |
| 76 | + } |
| 77 | + if !var.map.is_empty() { |
| 78 | + let first = var.map.first().unwrap(); |
| 79 | + return quote! { |
| 80 | + Self::#ident => #first.to_string() |
| 81 | + }; |
| 82 | + } |
| 83 | + if let Some(rename) = &var.rename { |
| 84 | + return quote! { |
| 85 | + Self::#ident => #rename.to_string() |
| 86 | + }; |
| 87 | + } |
| 88 | + |
| 89 | + panic!("unexpected situation") |
| 90 | +} |
| 91 | + |
| 92 | +struct EnumValueVariant<'a> { |
| 93 | + ident: &'a syn::Ident, |
| 94 | + is_other: bool, |
| 95 | + is_other_field: Option<syn::Field>, |
| 96 | + rename: Option<syn::LitStr>, |
| 97 | + map: Vec<syn::LitStr>, |
| 98 | +} |
| 99 | + |
| 100 | +impl<'a> EnumValueVariant<'a> { |
| 101 | + pub fn from_variant(v: &'a syn::Variant) -> Option<Self> { |
| 102 | + for meta_item in v |
| 103 | + .attrs |
| 104 | + .iter() |
| 105 | + .flat_map(|attr| get_xmlserde_meta_items(attr)) |
| 106 | + .flatten() |
| 107 | + { |
| 108 | + match meta_item { |
| 109 | + Meta::Path(path) if path == OTHER => { |
| 110 | + let field = match &v.fields { |
| 111 | + syn::Fields::Named(_) => panic!("unsupported named fields"), |
| 112 | + syn::Fields::Unnamed(fields_unnamed) => { |
| 113 | + fields_unnamed.unnamed.iter().next().cloned() |
| 114 | + } |
| 115 | + syn::Fields::Unit => None, |
| 116 | + }; |
| 117 | + if field.is_none() { |
| 118 | + panic!("other field should not have no field!") |
| 119 | + } |
| 120 | + return Some(Self { |
| 121 | + rename: None, |
| 122 | + ident: &v.ident, |
| 123 | + is_other: true, |
| 124 | + is_other_field: field, |
| 125 | + map: Vec::new(), |
| 126 | + }); |
| 127 | + } |
| 128 | + Meta::NameValue(m) if m.path == RENAME => { |
| 129 | + if let Ok(s) = get_lit_str(&m.value) { |
| 130 | + return Some(Self { |
| 131 | + rename: Some(s.clone()), |
| 132 | + ident: &v.ident, |
| 133 | + is_other: false, |
| 134 | + map: Vec::new(), |
| 135 | + is_other_field: None, |
| 136 | + }); |
| 137 | + } |
| 138 | + panic!(r#"please use `#[rename = "..."]`"#); |
| 139 | + } |
| 140 | + Meta::NameValue(m) if m.path == MAP => { |
| 141 | + if let Ok(s) = get_array_lit_str(&m.value) { |
| 142 | + return Some(Self { |
| 143 | + rename: None, |
| 144 | + ident: &v.ident, |
| 145 | + is_other: false, |
| 146 | + map: s.into_iter().map(|s| s.clone()).collect(), |
| 147 | + is_other_field: None, |
| 148 | + }); |
| 149 | + } |
| 150 | + panic!(r#"please use `#[map = ["..."]`"#); |
| 151 | + } |
| 152 | + _ => panic!("unexpected attribute"), |
| 153 | + } |
| 154 | + } |
| 155 | + None |
| 156 | + } |
| 157 | +} |
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