konfig_rust_derive/
lib.rs

1extern crate proc_macro;
2
3use proc_macro::TokenStream;
4use quote::quote;
5use syn::{DeriveInput, parse_macro_input};
6
7#[proc_macro_derive(KonfigSection)]
8pub fn konfig_section_derive(input: TokenStream) -> TokenStream {
9    let input = parse_macro_input!(input as DeriveInput);
10    let name = input.ident;
11
12    let expanded = quote! {
13        impl KonfigSection for #name {
14            fn name(&self) -> std::borrow::Cow<'_, str> {
15                std::borrow::Cow::Borrowed(stringify!(#name))
16            }
17            fn validate(&self) -> Result<(), KonfigError> { Ok(()) }
18            fn on_load(&self) -> Result<(), KonfigError> { Ok(()) }
19            fn to_bytes(&self, format: &FormatHandlerEnum) -> Result<Vec<u8>, KonfigError> {
20                format.marshal(self)
21            }
22            fn update_from_bytes(&mut self, bytes: &[u8], format: &FormatHandlerEnum) -> Result<(), KonfigError> {
23                let new_instance: #name = match format {
24                    FormatHandlerEnum::JSON(_) => {
25                        serde_json::from_slice(bytes)
26                            .map_err(|err| KonfigError::UnmarshalError(err.to_string()))?
27                    },
28                    FormatHandlerEnum::YAML(_) => {
29                        serde_yaml::from_slice(bytes)
30                            .map_err(|err| KonfigError::UnmarshalError(err.to_string()))?
31                    },
32                    FormatHandlerEnum::TOML(_) => {
33                        let s = std::str::from_utf8(bytes)
34                            .map_err(|err| KonfigError::UnmarshalError(err.to_string()))?;
35                        toml::from_str(s)
36                            .map_err(|err| KonfigError::UnmarshalError(err.to_string()))?
37                    },
38                };
39
40                *self = new_instance;
41                Ok(())
42            }
43        }
44    };
45
46    TokenStream::from(expanded)
47}
konfig_rust_derive/lib.rs

konfig_rust_derive/
lib.rs
