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mod attr;
use std::collections::HashMap;
use heck::KebabCase;
use proc_macro::TokenStream;
use proc_macro2::Span;
use quote::quote;
use syn::{DeriveInput, Error, Ident, Lit, Meta};
use crate::attr::AssignAttrs;
#[proc_macro_attribute]
pub fn config(_attrs: TokenStream, item: TokenStream) -> TokenStream {
let strukt = syn::parse_macro_input!(item as DeriveInput);
let struct_name = strukt.ident.clone();
let mut fields_name = vec![];
let mut fields_doc: HashMap<String, Option<String>> = HashMap::new();
let fields = if let syn::Data::Struct(fields) = &strukt.data {
fields.fields.iter().map(|field| {
let ty = field.ty.clone();
let ident = field.ident.clone();
let vis = field.vis.clone();
let colon = field.colon_token;
if let Some(ident) = &ident {
fields_name.push(ident.to_string());
fields_doc.insert(ident.to_string(), None);
}
let attrs =
field
.attrs
.clone()
.into_iter()
.filter(|attr| match attr.path.get_ident() {
Some(attr_ident) if attr_ident == "serde" => {
attr.parse_args::<AssignAttrs>().is_err()
}
Some(attr_ident) if attr_ident == "doc" => {
let doc = match attr.parse_meta() {
Ok(Meta::NameValue(ref nv)) if nv.path.is_ident("doc") => {
if let Lit::Str(lit_str) = &nv.lit {
Some(lit_str.value())
} else {
None
}
}
_ => None,
};
if let Some(ident) = &ident {
*fields_doc.get_mut(&ident.to_string()).unwrap() = doc;
}
true
}
_ => true,
});
let res = quote! {
#(#attrs)*
#vis #ident #colon Option<#ty>,
};
res
})
} else {
return TokenStream::from(
Error::new_spanned(strukt, "must be a struct").to_compile_error(),
);
};
let struct_vis = strukt.vis.clone();
let struct_gen = strukt.generics.clone();
let struct_where = strukt.generics.where_clause.clone();
let struct_attrs = strukt.attrs.clone();
let opt_struct_name = Ident::new(
format!("Opt{}", struct_name.to_string()).as_str(),
Span::call_site(),
);
let opt_struct = quote! {
#(#struct_attrs)*
#struct_vis struct #opt_struct_name #struct_gen #struct_where {
#(#fields)*
}
};
let docs = fields_doc.values().map(|doc| match doc {
Some(doc) => doc.trim().to_string(),
None => String::new(),
});
let field_names_clap = fields_name
.clone()
.into_iter()
.map(|ref field_name| field_name.to_kebab_case());
let code = quote! {
#[derive(::twelf::reexports::serde::Deserialize)]
#strukt
impl #struct_gen #struct_name #struct_gen #struct_where {
pub fn with_layers(layers: &[::twelf::Layer]) -> Result<Self, ::twelf::Error> {
use std::iter::FromIterator;
let mut res: std::collections::HashMap<String, ::twelf::reexports::serde_json::Value> = std::collections::HashMap::new();
for layer in layers {
let extension = Self::parse(layer)?;
res.extend(
extension
.as_object()
.ok_or_else(|| ::twelf::Error::InvalidFormat)?
.to_owned()
.into_iter().filter(|(_k, v)| !v.is_null()),
);
}
::twelf::reexports::log::debug!(target: "twelf", "configuration:");
for (key, val) in &res {
::twelf::reexports::log::debug!(target: "twelf", "{}={}", key, val);
}
::twelf::reexports::serde_json::from_value(::twelf::reexports::serde_json::Value::Object(::twelf::reexports::serde_json::Map::from_iter(res.into_iter()))).map_err(|e| ::twelf::Error::Deserialize(e.to_string()))
}
#[cfg(feature = "clap")]
pub fn clap_args() -> Vec<::twelf::reexports::clap::Arg<'static, 'static>> {
vec![#(
::twelf::reexports::clap::Arg::with_name(#fields_name).long(#field_names_clap).help(#docs).takes_value(true).global(true)
),*]
}
fn parse(priority: &::twelf::Layer) -> Result<::twelf::reexports::serde_json::Value, ::twelf::Error>
{
#[derive(::twelf::reexports::serde::Deserialize, ::twelf::reexports::serde::Serialize)]
#opt_struct
let res = match priority {
::twelf::Layer::Env(prefix) => match prefix {
Some(prefix) => {
let tmp_cfg: #opt_struct_name #struct_gen = ::twelf::reexports::envy::prefixed(prefix).from_env()?;
::twelf::reexports::serde_json::to_value(tmp_cfg)
},
None => {
let tmp_cfg: #opt_struct_name #struct_gen = ::twelf::reexports::envy::from_env()?;
::twelf::reexports::serde_json::to_value(tmp_cfg)
},
}?,
#[cfg(feature = "json")]
::twelf::Layer::Json(filepath) => ::twelf::reexports::serde_json::from_reader(std::fs::File::open(filepath)?)?,
#[cfg(feature = "toml")]
::twelf::Layer::Toml(filepath) => ::twelf::reexports::toml::from_str(&std::fs::read_to_string(filepath)?)?,
#[cfg(feature = "yaml")]
::twelf::Layer::Yaml(filepath) => ::twelf::reexports::serde_yaml::from_str(&std::fs::read_to_string(filepath)?)?,
#[cfg(feature = "dhall")]
::twelf::Layer::Dhall(filepath) => ::twelf::reexports::serde_dhall::from_str(&std::fs::read_to_string(filepath)?).parse()?,
#[cfg(feature = "ini")]
::twelf::Layer::Ini(filepath) => {
let tmp_cfg: #opt_struct_name #struct_gen = ::twelf::reexports::serde_ini::from_str(&std::fs::read_to_string(filepath)?)?;
::twelf::reexports::serde_json::to_value(tmp_cfg)?
},
#[cfg(feature = "clap")]
::twelf::Layer::Clap(matches) => {
let mut map: std::collections::HashMap<String, String> = std::collections::HashMap::new();
#(
if let Some(vmatch) = matches.value_of(#fields_name) {
map.insert(String::from(#fields_name), vmatch.to_string());
}
)*
let tmp_cfg: #opt_struct_name #struct_gen = ::twelf::reexports::envy::from_iter(map.into_iter())?;
::twelf::reexports::serde_json::to_value(tmp_cfg)?
},
};
Ok(res)
}
}
};
TokenStream::from(code)
}