46 lines
1.3 KiB
Rust
46 lines
1.3 KiB
Rust
use syn;
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use quote;
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pub fn build(ast: &syn::DeriveInput) -> quote::Tokens {
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let fields = match ast.body {
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syn::Body::Enum(_) => panic!("Deriving DnsPacketData not supported for enum types"),
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syn::Body::Struct(syn::VariantData::Struct(ref s)) => s,
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syn::Body::Struct(_) => panic!("Deriving DnsPacketData not supported for unit / tuple struct types"),
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};
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if !ast.generics.ty_params.is_empty() {
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panic!("Type parameters not supported for deriving DnsPacketData");
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}
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if !ast.generics.where_clause.predicates.is_empty() {
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panic!("Where clauses not supported for deriving DnsPacketData");
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}
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if !ast.generics.lifetimes.is_empty() {
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panic!("Lifetimes not supported for deriving DnsPacketData");
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}
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let name = &ast.ident;
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let mut parse_fields = quote!{};
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for field in fields {
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let field_name = field.ident.as_ref().unwrap();
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let ctx_msg = format!("failed parsing field {}::{}", name, field_name);
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parse_fields = quote!{#parse_fields
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#field_name: DnsPacketData::deserialize(_data).context(#ctx_msg)?,
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};
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}
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quote!{
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impl ::dnsbox_base::ser::DnsPacketData for #name {
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#[allow(unused_imports)]
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fn deserialize(_data: &mut ::std::io::Cursor<::dnsbox_base::bytes::Bytes>) -> ::dnsbox_base::errors::Result<Self> {
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use ::dnsbox_base::failure::ResultExt;
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use ::dnsbox_base::ser::DnsPacketData;
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Ok(#name{ #parse_fields })
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}
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}
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}
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}
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