103 lines
3.2 KiB
Rust
103 lines
3.2 KiB
Rust
use proc_macro::TokenStream;
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use quote::quote;
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use syn::{Data, DeriveInput, Fields, parse_macro_input};
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/// Derives the `MergeFrom` trait for a struct.
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///
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/// This macro automatically implements `MergeFrom` by calling `merge_from`
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/// on all fields in the struct.
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///
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/// # Example
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///
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/// ```ignore
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/// #[derive(Clone, MergeFrom)]
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/// struct MySettings {
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/// field1: Option<String>,
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/// field2: SomeOtherSettings,
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/// }
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/// ```
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#[proc_macro_derive(MergeFrom)]
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pub fn derive_merge_from(input: TokenStream) -> TokenStream {
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let input = parse_macro_input!(input as DeriveInput);
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let name = &input.ident;
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let (impl_generics, ty_generics, where_clause) = input.generics.split_for_impl();
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let merge_body = match &input.data {
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Data::Struct(data_struct) => match &data_struct.fields {
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Fields::Named(fields) => {
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let field_merges = fields.named.iter().map(|field| {
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let field_name = &field.ident;
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quote! {
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self.#field_name.merge_from(&other.#field_name);
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}
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});
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quote! {
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#(#field_merges)*
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}
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}
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Fields::Unnamed(fields) => {
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let field_merges = fields.unnamed.iter().enumerate().map(|(i, _)| {
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let field_index = syn::Index::from(i);
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quote! {
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self.#field_index.merge_from(&other.#field_index);
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}
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});
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quote! {
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#(#field_merges)*
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}
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}
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Fields::Unit => {
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quote! {
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// No fields to merge for unit structs
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}
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}
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},
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Data::Enum(_) => {
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quote! {
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*self = other.clone();
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}
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}
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Data::Union(_) => {
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panic!("MergeFrom cannot be derived for unions");
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}
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};
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let expanded = quote! {
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impl #impl_generics crate::merge_from::MergeFrom for #name #ty_generics #where_clause {
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fn merge_from(&mut self, other: &Self) {
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use crate::merge_from::MergeFrom as _;
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#merge_body
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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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/// Registers the setting type with the SettingsStore. Note that you need to
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/// have `gpui` in your dependencies for this to work.
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#[proc_macro_derive(RegisterSetting)]
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pub fn derive_register_setting(input: TokenStream) -> TokenStream {
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let input = syn::parse_macro_input!(input as DeriveInput);
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let type_name = &input.ident;
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quote! {
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settings::private::inventory::submit! {
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settings::private::RegisteredSetting {
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settings_value: || {
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Box::new(settings::private::SettingValue::<#type_name> {
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global_value: None,
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local_values: Vec::new(),
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})
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},
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from_settings: |content| Box::new(<#type_name as settings::Settings>::from_settings(content)),
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id: || std::any::TypeId::of::<#type_name>(),
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}
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}
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}
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.into()
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}
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