tenant.openagents/omega

1use proc_macro::TokenStream;
2
3use quote::quote;
4use syn::{
5    Data, DeriveInput, Field, Fields, ItemEnum, ItemStruct, Type, parse_macro_input, parse_quote,
6};
7
8/// Derives the `MergeFrom` trait for a struct.
9///
10/// This macro automatically implements `MergeFrom` by calling `merge_from`
11/// on all fields in the struct.
12///
13/// # Example
14///
15/// ```ignore
16/// #[derive(Clone, MergeFrom)]
17/// struct MySettings {
18///     field1: Option<String>,
19///     field2: SomeOtherSettings,
20/// }
21/// ```
22#[proc_macro_derive(MergeFrom)]
23pub fn derive_merge_from(input: TokenStream) -> TokenStream {
24    let input = parse_macro_input!(input as DeriveInput);
25
26    let name = &input.ident;
27    let (impl_generics, ty_generics, where_clause) = input.generics.split_for_impl();
28
29    let merge_body = match &input.data {
30        Data::Struct(data_struct) => match &data_struct.fields {
31            Fields::Named(fields) => {
32                let field_merges = fields.named.iter().map(|field| {
33                    let field_name = &field.ident;
34                    quote! {
35                        self.#field_name.merge_from(&other.#field_name);
36                    }
37                });
38
39                quote! {
40                    #(#field_merges)*
41                }
42            }
43            Fields::Unnamed(fields) => {
44                let field_merges = fields.unnamed.iter().enumerate().map(|(i, _)| {
45                    let field_index = syn::Index::from(i);
46                    quote! {
47                        self.#field_index.merge_from(&other.#field_index);
48                    }
49                });
50
51                quote! {
52                    #(#field_merges)*
53                }
54            }
55            Fields::Unit => {
56                quote! {
57                    // No fields to merge for unit structs
58                }
59            }
60        },
61        Data::Enum(_) => {
62            quote! {
63                *self = other.clone();
64            }
65        }
66        Data::Union(_) => {
67            panic!("MergeFrom cannot be derived for unions");
68        }
69    };
70
71    let expanded = quote! {
72        impl #impl_generics crate::merge_from::MergeFrom for #name #ty_generics #where_clause {
73            fn merge_from(&mut self, other: &Self) {
74                use crate::merge_from::MergeFrom as _;
75                #merge_body
76            }
77        }
78    };
79
80    TokenStream::from(expanded)
81}
82
83/// Registers the setting type with the SettingsStore. Note that you need to
84/// have `gpui` in your dependencies for this to work.
85#[proc_macro_derive(RegisterSetting)]
86pub fn derive_register_setting(input: TokenStream) -> TokenStream {
87    let input = syn::parse_macro_input!(input as DeriveInput);
88    let type_name = &input.ident;
89
90    quote! {
91        settings::private::inventory::submit! {
92            settings::private::RegisteredSetting {
93                settings_value: || {
94                    Box::new(settings::private::SettingValue::<#type_name> {
95                        global_value: None,
96                        local_values: Vec::new(),
97                    })
98                },
99                from_settings: |content| Box::new(<#type_name as settings::Settings>::from_settings(content)),
100                id: || std::any::TypeId::of::<#type_name>(),
101            }
102        }
103    }
104    .into()
105}
106
107// Adds serde attributes to each field with type Option<T>:
108// #serde(default, skip_serializing_if = "Option::is_none", deserialize_with = "settings::deserialize_fallible")
109#[proc_macro_attribute]
110pub fn with_fallible_options(_args: TokenStream, input: TokenStream) -> TokenStream {
111    fn apply_on_fields(fields: &mut Fields) {
112        match fields {
113            Fields::Unit => {}
114            Fields::Named(fields) => {
115                for field in &mut fields.named {
116                    add_if_option(field)
117                }
118            }
119            Fields::Unnamed(fields) => {
120                for field in &mut fields.unnamed {
121                    add_if_option(field)
122                }
123            }
124        }
125    }
126
127    fn add_if_option(field: &mut Field) {
128        match &field.ty {
129            Type::Path(syn::TypePath { qself: None, path })
130                if path.leading_colon.is_none()
131                    && path.segments.len() == 1
132                    && path.segments[0].ident == "Option" => {}
133            _ => return,
134        }
135        let attr = parse_quote!(
136            #[serde(default, skip_serializing_if = "Option::is_none", deserialize_with="crate::fallible_options::deserialize")]
137        );
138        field.attrs.push(attr);
139    }
140
141    if let Ok(mut input) = syn::parse::<ItemStruct>(input.clone()) {
142        apply_on_fields(&mut input.fields);
143        quote!(#input).into()
144    } else if let Ok(mut input) = syn::parse::<ItemEnum>(input) {
145        for variant in &mut input.variants {
146            apply_on_fields(&mut variant.fields);
147        }
148        quote!(#input).into()
149    } else {
150        panic!("with_fallible_options can only be applied to struct or enum definitions.");
151    }
152}
153