Add macro and attributes for automatic watching of Composite structs and their components
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@ -1,5 +1,6 @@
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use proc_macro::TokenStream;
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use quote::quote;
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use syn::{parse_macro_input, Data, DeriveInput, Field, Fields, FieldsNamed};
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#[proc_macro_derive(Updateable)]
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pub fn updateable_macro_derive(input: TokenStream) -> TokenStream {
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@ -16,3 +17,99 @@ pub fn updateable_macro_derive(input: TokenStream) -> TokenStream {
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}
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.into()
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}
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#[proc_macro_attribute]
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pub fn observe_option(_args: TokenStream, input: TokenStream) -> TokenStream {
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input
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}
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#[proc_macro_attribute]
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pub fn observe_option_vec(_args: TokenStream, input: TokenStream) -> TokenStream {
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input
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}
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#[proc_macro_attribute]
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pub fn observe(_args: TokenStream, input: TokenStream) -> TokenStream {
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input
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}
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#[proc_macro_attribute]
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pub fn observe_vec(_args: TokenStream, input: TokenStream) -> TokenStream {
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input
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}
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#[proc_macro_derive(
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Composite,
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attributes(observe_option_vec, observe_option, observe, observe_vec)
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)]
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pub fn composite_derive(input: TokenStream) -> TokenStream {
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let input = parse_macro_input!(input as DeriveInput);
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let process_field = |field: &Field| {
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let field_name = &field.ident;
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let attrs = &field.attrs;
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let observe_option = attrs
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.iter()
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.any(|attr| attr.path().is_ident("observe_option"));
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let observe_option_vec = attrs
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.iter()
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.any(|attr| attr.path().is_ident("observe_option_vec"));
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let observe = attrs.iter().any(|attr| attr.path().is_ident("observe"));
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let observe_vec = attrs.iter().any(|attr| attr.path().is_ident("observe_vec"));
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let field_is_arc_rwlock = if let syn::Type::Path(type_path) = &field.ty {
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type_path.path.segments.last().map_or(false, |segment| {
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segment.ident == "Arc" || segment.ident == "RwLock"
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})
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} else {
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false
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};
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if field_is_arc_rwlock {
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match (observe_option, observe_option_vec, observe, observe_vec) {
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(true, _, _, _) => quote! {
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#field_name: option_observe_fn(self.#field_name)
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},
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(_, true, _, _) => quote! {
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#field_name: option_vec_observe_fn(self.#field_name)
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},
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(_, _, true, _) => quote! {
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#field_name: value_observe_fn(self.#field_name)
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},
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(_, _, _, true) => quote! {
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#field_name: vec_observe_fn(self.#field_name)
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},
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_ => quote! {
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#field_name: self.#field_name
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},
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}
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} else {
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panic!("Fields must be of type Arc<RwLock<T: Updateable>>");
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}
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};
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match &input.data {
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Data::Struct(data) => match &data.fields {
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Fields::Named(FieldsNamed { named, .. }) => {
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let field_exprs = named.iter().map(process_field);
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let ident = &input.ident;
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let expanded = quote! {
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impl<T: Updateable> Composite<T> for #ident {
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fn watch_whole(self) -> Self {
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Self {
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#(#field_exprs,)*
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}
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}
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}
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};
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TokenStream::from(expanded)
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}
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_ => panic!("Composite derive macro only supports named fields"),
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},
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_ => panic!("Composite derive macro only supports structs"),
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}
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}
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