|
| 1 | +use heck::ToSnakeCase; |
| 2 | +use proc_macro2::{self, TokenStream}; |
| 3 | +use quote::{quote, quote_spanned}; |
| 4 | +use syn::{ |
| 5 | + punctuated::Punctuated, DataEnum, DataStruct, DeriveInput, Expr, Fields, LitStr, Variant, |
| 6 | +}; |
| 7 | + |
| 8 | +fn must_be_valid_iden(name: &str) -> bool { |
| 9 | + // can only begin with [a-z_] |
| 10 | + name.chars() |
| 11 | + .take(1) |
| 12 | + .all(|c| c == '_' || c.is_ascii_alphabetic()) |
| 13 | + && name.chars().all(|c| c == '_' || c.is_ascii_alphanumeric()) |
| 14 | +} |
| 15 | + |
| 16 | +fn impl_iden_for_unit_struct( |
| 17 | + ident: &proc_macro2::Ident, |
| 18 | + new_iden: &str, |
| 19 | +) -> proc_macro2::TokenStream { |
| 20 | + let prepare = if must_be_valid_iden(new_iden) { |
| 21 | + quote! { |
| 22 | + fn prepare(&self, s: &mut dyn ::std::fmt::Write, q: sea_orm::sea_query::Quote) { |
| 23 | + write!(s, "{}", q.left()).unwrap(); |
| 24 | + self.unquoted(s); |
| 25 | + write!(s, "{}", q.right()).unwrap(); |
| 26 | + } |
| 27 | + } |
| 28 | + } else { |
| 29 | + quote! {} |
| 30 | + }; |
| 31 | + quote! { |
| 32 | + impl sea_orm::sea_query::Iden for #ident { |
| 33 | + #prepare |
| 34 | + |
| 35 | + fn unquoted(&self, s: &mut dyn ::std::fmt::Write) { |
| 36 | + write!(s, #new_iden).unwrap(); |
| 37 | + } |
| 38 | + } |
| 39 | + } |
| 40 | +} |
| 41 | + |
| 42 | +fn impl_iden_for_enum( |
| 43 | + ident: &proc_macro2::Ident, |
| 44 | + variants: Punctuated<Variant, syn::token::Comma>, |
| 45 | +) -> proc_macro2::TokenStream { |
| 46 | + let variants = variants.iter(); |
| 47 | + let mut all_valid = true; |
| 48 | + |
| 49 | + let match_pair: Vec<TokenStream> = variants |
| 50 | + .map(|v| { |
| 51 | + let var_ident = &v.ident; |
| 52 | + let mut var_name = var_ident.to_string().to_snake_case(); |
| 53 | + v.attrs |
| 54 | + .iter() |
| 55 | + .filter(|attr| attr.path().is_ident("sea_orm")) |
| 56 | + .try_for_each(|attr| { |
| 57 | + attr.parse_nested_meta(|meta| { |
| 58 | + if meta.path.is_ident("iden") { |
| 59 | + let litstr: LitStr = meta.value()?.parse()?; |
| 60 | + var_name = litstr.value(); |
| 61 | + all_valid &= must_be_valid_iden(var_name.as_str()); |
| 62 | + } else { |
| 63 | + // Reads the value expression to advance the parse stream. |
| 64 | + // Some parameters do not have any value, |
| 65 | + // so ignoring an error occurred here. |
| 66 | + let _: Option<Expr> = meta.value().and_then(|v| v.parse()).ok(); |
| 67 | + } |
| 68 | + Ok(()) |
| 69 | + }) |
| 70 | + }) |
| 71 | + .expect("something something"); |
| 72 | + quote! { Self::#var_ident => write!(s, "{}", #var_name).unwrap() } |
| 73 | + }) |
| 74 | + .collect(); |
| 75 | + |
| 76 | + let match_arms: TokenStream = quote! { #(#match_pair),* }; |
| 77 | + |
| 78 | + let prepare = if all_valid { |
| 79 | + quote! { |
| 80 | + fn prepare(&self, s: &mut dyn ::std::fmt::Write, q: sea_orm::sea_query::Quote) { |
| 81 | + write!(s, "{}", q.left()).unwrap(); |
| 82 | + self.unquoted(s); |
| 83 | + write!(s, "{}", q.right()).unwrap(); |
| 84 | + } |
| 85 | + } |
| 86 | + } else { |
| 87 | + quote! {} |
| 88 | + }; |
| 89 | + |
| 90 | + quote! { |
| 91 | + impl sea_orm::sea_query::Iden for #ident { |
| 92 | + #prepare |
| 93 | + |
| 94 | + fn unquoted(&self, s: &mut dyn ::std::fmt::Write) { |
| 95 | + match self { |
| 96 | + #match_arms |
| 97 | + }; |
| 98 | + } |
| 99 | + } |
| 100 | + } |
| 101 | +} |
| 102 | + |
| 103 | +pub fn expand_derive_iden(input: DeriveInput) -> syn::Result<TokenStream> { |
| 104 | + let DeriveInput { ident, data, .. } = input; |
| 105 | + |
| 106 | + let mut new_iden: TokenStream = ident.to_string().to_snake_case().parse().unwrap(); |
| 107 | + input |
| 108 | + .attrs |
| 109 | + .iter() |
| 110 | + .filter(|attr| attr.path().is_ident("sea_orm")) |
| 111 | + .try_for_each(|attr| { |
| 112 | + attr.parse_nested_meta(|meta| { |
| 113 | + if meta.path.is_ident("iden") { |
| 114 | + let litstr: LitStr = meta.value()?.parse()?; |
| 115 | + new_iden = syn::parse_str::<TokenStream>(&litstr.value())?; |
| 116 | + } else { |
| 117 | + // Reads the value expression to advance the parse stream. |
| 118 | + // Some parameters do not have any value, |
| 119 | + // so ignoring an error occurred here. |
| 120 | + let _: Option<Expr> = meta.value().and_then(|v| v.parse()).ok(); |
| 121 | + } |
| 122 | + Ok(()) |
| 123 | + }) |
| 124 | + })?; |
| 125 | + |
| 126 | + // Currently we only support enums and unit structs |
| 127 | + match data { |
| 128 | + syn::Data::Enum(DataEnum { variants, .. }) => { |
| 129 | + if variants.is_empty() { |
| 130 | + Ok(TokenStream::new()) |
| 131 | + } else { |
| 132 | + Ok(impl_iden_for_enum(&ident, variants)) |
| 133 | + } |
| 134 | + } |
| 135 | + syn::Data::Struct(DataStruct { |
| 136 | + fields: Fields::Unit, |
| 137 | + .. |
| 138 | + }) => Ok(impl_iden_for_unit_struct( |
| 139 | + &ident, |
| 140 | + new_iden.to_string().as_str(), |
| 141 | + )), |
| 142 | + _ => Ok(quote_spanned! { |
| 143 | + ident.span() => compile_error!("you can only derive DeriveIden on unit struct or enum"); |
| 144 | + }), |
| 145 | + } |
| 146 | +} |
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