diesel_derives/
has_query.rs

1use proc_macro2::TokenStream;
2use syn::punctuated::Punctuated;
3use syn::{parse_quote, DeriveInput};
4
5use crate::model::{CheckForBackend, Model};
6
7pub(crate) fn derive(item: DeriveInput) -> syn::Result<TokenStream> {
8    // other required traits
9    let mut checks = Punctuated::new();
10    if cfg!(feature = "postgres") {
11        checks.push(parse_quote! {diesel::pg::Pg});
12    }
13    if cfg!(feature = "sqlite") {
14        checks.push(parse_quote! {diesel::sqlite::Sqlite});
15    }
16    if cfg!(feature = "mysql") {
17        checks.push(parse_quote! {diesel::mysql::Mysql});
18    }
19    let selectable = super::selectable::derive(
20        item.clone(),
21        (!checks.is_empty()).then_some(CheckForBackend::Backends(checks)),
22    )?;
23    let queryable = super::queryable::derive(item.clone())?;
24
25    let ident = &item.ident;
26    let model = Model::from_item(&item, false, false)?;
27    let (_original_impl_generics, ty_generics, _original_where_clause) =
28        item.generics.split_for_impl();
29
30    let mut generics = item.generics.clone();
31    generics
32        .params
33        .push(parse_quote!(__DB: diesel::backend::Backend));
34
35    let (impl_generics, _, where_clause) = generics.split_for_impl();
36
37    let mut errors = Vec::new();
38
39    let (query_expr, query_type) = if let Some(base_query) = model.base_query {
40        if let Some(query_type) = model.base_query_type {
41            (base_query, query_type)
42        } else {
43            use dsl_auto_type::auto_type::expression_type_inference as type_inference;
44
45            let (inferred_type, infer_errors) = type_inference::infer_expression_type(
46                &base_query,
47                None,
48                &type_inference::InferrerSettings::builder()
49                    .dsl_path(parse_quote!(diesel::dsl))
50                    .function_types_case(crate::AUTO_TYPE_DEFAULT_FUNCTION_TYPE_CASE)
51                    .method_types_case(crate::AUTO_TYPE_DEFAULT_METHOD_TYPE_CASE)
52                    .build(),
53            );
54
55            errors = infer_errors
56                .into_iter()
57                .map(|e| e.into_compile_error())
58                .collect();
59            (base_query, inferred_type)
60        }
61    } else {
62        let table_name = &model.table_names()[0];
63        let query_type =
64            parse_quote!(<#table_name::table as diesel::query_builder::AsQuery>::Query);
65
66        let query_expr = parse_quote! {
67            diesel::query_builder::AsQuery::as_query(#table_name::table)
68        };
69        (query_expr, query_type)
70    };
71
72    let mut query_model = crate::util::wrap_in_dummy_mod(quote::quote! {
73        impl #impl_generics diesel::HasQuery<__DB> for #ident #ty_generics #where_clause {
74            type BaseQuery = #query_type;
75
76            fn base_query() -> Self::BaseQuery {
77                #query_expr
78            }
79
80        }
81        #(#errors)*
82    });
83    query_model.extend(selectable);
84    query_model.extend(queryable);
85    Ok(query_model)
86}
diesel_derives/has_query.rs

diesel_derives/
has_query.rs
