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/* 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
use proc_macro2::{Ident, TokenStream};
use quote::quote;
use syn::ext::IdentExt;
use super::gen_ffi_function;
use crate::export::ExportFnArgs;
use crate::fnsig::FnSignature;
use crate::util::extract_docstring;
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 docstring = extract_docstring(&item.attrs)?;
let ffi_func = gen_ffi_function(
&FnSignature::new_method(
self_ident.clone(),
item.sig.clone(),
ExportFnArgs::default(),
docstring.clone(),
)?,
None,
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,
ExportFnArgs::default(),
docstring,
)?
.metadata_expr()?;
Ok((ffi_func, method_meta))
}