summaryrefslogtreecommitdiffstats
path: root/third_party/rust/uniffi_macros/src/export/utrait.rs
blob: 3db09ea2b7d3868c20ab00e34292708811ba13b2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

use proc_macro2::{Ident, TokenStream};
use quote::quote;
use syn::ext::IdentExt;

use super::{attributes::ExportAttributeArguments, gen_ffi_function};
use crate::fnsig::FnSignature;
use uniffi_meta::UniffiTraitDiscriminants;

pub(crate) fn expand_uniffi_trait_export(
    self_ident: Ident,
    uniffi_traits: Vec<UniffiTraitDiscriminants>,
) -> syn::Result<TokenStream> {
    let udl_mode = false;
    let mut impl_items = Vec::new();
    let mut global_items = Vec::new();
    for trait_id in uniffi_traits {
        match trait_id {
            UniffiTraitDiscriminants::Debug => {
                let method = quote! {
                    fn uniffi_trait_debug(&self) -> String {
                        ::uniffi::deps::static_assertions::assert_impl_all!(#self_ident: ::std::fmt::Debug);
                        format!("{:?}", self)
                    }
                };
                let (ffi_func, method_meta) =
                    process_uniffi_trait_method(&method, &self_ident, udl_mode)?;
                // metadata for the trait - which includes metadata for the method.
                let discr = UniffiTraitDiscriminants::Debug as u8;
                let trait_meta = crate::util::create_metadata_items(
                    "uniffi_trait",
                    &format!("{}_Debug", self_ident.unraw()),
                    quote! {
                        ::uniffi::MetadataBuffer::from_code(::uniffi::metadata::codes::UNIFFI_TRAIT)
                        .concat_value(#discr)
                        .concat(#method_meta)
                    },
                    None,
                );
                impl_items.push(method);
                global_items.push(ffi_func);
                global_items.push(trait_meta);
            }
            UniffiTraitDiscriminants::Display => {
                let method = quote! {
                    fn uniffi_trait_display(&self) -> String {
                        ::uniffi::deps::static_assertions::assert_impl_all!(#self_ident: ::std::fmt::Display);
                        format!("{}", self)
                    }
                };
                let (ffi_func, method_meta) =
                    process_uniffi_trait_method(&method, &self_ident, udl_mode)?;
                // metadata for the trait - which includes metadata for the method.
                let discr = UniffiTraitDiscriminants::Display as u8;
                let trait_meta = crate::util::create_metadata_items(
                    "uniffi_trait",
                    &format!("{}_Display", self_ident.unraw()),
                    quote! {
                        ::uniffi::MetadataBuffer::from_code(::uniffi::metadata::codes::UNIFFI_TRAIT)
                        .concat_value(#discr)
                        .concat(#method_meta)
                    },
                    None,
                );
                impl_items.push(method);
                global_items.push(ffi_func);
                global_items.push(trait_meta);
            }
            UniffiTraitDiscriminants::Hash => {
                let method = quote! {
                    fn uniffi_trait_hash(&self) -> u64 {
                        use ::std::hash::{Hash, Hasher};
                        ::uniffi::deps::static_assertions::assert_impl_all!(#self_ident: Hash);
                        let mut s = ::std::collections::hash_map::DefaultHasher::new();
                        Hash::hash(self, &mut s);
                        s.finish()
                    }
                };
                let (ffi_func, method_meta) =
                    process_uniffi_trait_method(&method, &self_ident, udl_mode)?;
                // metadata for the trait - which includes metadata for the hash method.
                let discr = UniffiTraitDiscriminants::Hash as u8;
                let trait_meta = crate::util::create_metadata_items(
                    "uniffi_trait",
                    &format!("{}_Hash", self_ident.unraw()),
                    quote! {
                        ::uniffi::MetadataBuffer::from_code(::uniffi::metadata::codes::UNIFFI_TRAIT)
                        .concat_value(#discr)
                        .concat(#method_meta)
                    },
                    None,
                );
                impl_items.push(method);
                global_items.push(ffi_func);
                global_items.push(trait_meta);
            }
            UniffiTraitDiscriminants::Eq => {
                let method_eq = quote! {
                    fn uniffi_trait_eq_eq(&self, other: &#self_ident) -> bool {
                        use ::std::cmp::PartialEq;
                        uniffi::deps::static_assertions::assert_impl_all!(#self_ident: PartialEq); // This object has a trait method which requires `PartialEq` be implemented.
                        PartialEq::eq(self, other)
                    }
                };
                let method_ne = quote! {
                    fn uniffi_trait_eq_ne(&self, other: &#self_ident) -> bool {
                        use ::std::cmp::PartialEq;
                        uniffi::deps::static_assertions::assert_impl_all!(#self_ident: PartialEq); // This object has a trait method which requires `PartialEq` be implemented.
                        PartialEq::ne(self, other)
                    }
                };
                let (ffi_func_eq, method_meta_eq) =
                    process_uniffi_trait_method(&method_eq, &self_ident, udl_mode)?;
                let (ffi_func_ne, method_meta_ne) =
                    process_uniffi_trait_method(&method_ne, &self_ident, udl_mode)?;
                // metadata for the trait itself.
                let discr = UniffiTraitDiscriminants::Eq as u8;
                let trait_meta = crate::util::create_metadata_items(
                    "uniffi_trait",
                    &format!("{}_Eq", self_ident.unraw()),
                    quote! {
                        ::uniffi::MetadataBuffer::from_code(::uniffi::metadata::codes::UNIFFI_TRAIT)
                        .concat_value(#discr)
                        .concat(#method_meta_eq)
                        .concat(#method_meta_ne)
                    },
                    None,
                );
                impl_items.push(method_eq);
                impl_items.push(method_ne);
                global_items.push(ffi_func_eq);
                global_items.push(ffi_func_ne);
                global_items.push(trait_meta);
            }
        }
    }
    Ok(quote! {
        #[doc(hidden)]
        impl #self_ident {
            #(#impl_items)*
        }
        #(#global_items)*
    })
}

fn process_uniffi_trait_method(
    method: &TokenStream,
    self_ident: &Ident,
    udl_mode: bool,
) -> syn::Result<(TokenStream, TokenStream)> {
    let item = syn::parse(method.clone().into())?;

    let syn::Item::Fn(item) = item else {
        unreachable!()
    };

    let ffi_func = gen_ffi_function(
        &FnSignature::new_method(self_ident.clone(), item.sig.clone())?,
        &ExportAttributeArguments::default(),
        udl_mode,
    )?;
    // metadata for the method, which will be packed inside metadata for the trait.
    let method_meta = FnSignature::new_method(self_ident.clone(), item.sig)?.metadata_expr()?;
    Ok((ffi_func, method_meta))
}