diff options
Diffstat (limited to 'third_party/rust/uniffi_macros/src/export/scaffolding.rs')
| -rw-r--r-- | third_party/rust/uniffi_macros/src/export/scaffolding.rs | 123 |
1 files changed, 77 insertions, 46 deletions
diff --git a/third_party/rust/uniffi_macros/src/export/scaffolding.rs b/third_party/rust/uniffi_macros/src/export/scaffolding.rs index f120ccc880..fa7b61deca 100644 --- a/third_party/rust/uniffi_macros/src/export/scaffolding.rs +++ b/third_party/rust/uniffi_macros/src/export/scaffolding.rs @@ -6,12 +6,12 @@ use proc_macro2::{Ident, TokenStream}; use quote::quote; use std::iter; -use super::attributes::{AsyncRuntime, ExportAttributeArguments}; -use crate::fnsig::{FnKind, FnSignature, NamedArg}; +use super::attributes::AsyncRuntime; +use crate::fnsig::{FnKind, FnSignature}; pub(super) fn gen_fn_scaffolding( sig: FnSignature, - arguments: &ExportAttributeArguments, + ar: &Option<AsyncRuntime>, udl_mode: bool, ) -> syn::Result<TokenStream> { if sig.receiver.is_some() { @@ -21,7 +21,7 @@ pub(super) fn gen_fn_scaffolding( )); } if !sig.is_async { - if let Some(async_runtime) = &arguments.async_runtime { + if let Some(async_runtime) = ar { return Err(syn::Error::new_spanned( async_runtime, "this attribute is only allowed on async functions", @@ -32,7 +32,7 @@ pub(super) fn gen_fn_scaffolding( sig.metadata_items() .unwrap_or_else(syn::Error::into_compile_error) }); - let scaffolding_func = gen_ffi_function(&sig, arguments, udl_mode)?; + let scaffolding_func = gen_ffi_function(&sig, ar, udl_mode)?; Ok(quote! { #scaffolding_func #metadata_items @@ -41,7 +41,7 @@ pub(super) fn gen_fn_scaffolding( pub(super) fn gen_constructor_scaffolding( sig: FnSignature, - arguments: &ExportAttributeArguments, + ar: &Option<AsyncRuntime>, udl_mode: bool, ) -> syn::Result<TokenStream> { if sig.receiver.is_some() { @@ -50,14 +50,11 @@ pub(super) fn gen_constructor_scaffolding( "constructors must not have a self parameter", )); } - if sig.is_async { - return Err(syn::Error::new(sig.span, "constructors can't be async")); - } let metadata_items = (!udl_mode).then(|| { sig.metadata_items() .unwrap_or_else(syn::Error::into_compile_error) }); - let scaffolding_func = gen_ffi_function(&sig, arguments, udl_mode)?; + let scaffolding_func = gen_ffi_function(&sig, ar, udl_mode)?; Ok(quote! { #scaffolding_func #metadata_items @@ -66,7 +63,7 @@ pub(super) fn gen_constructor_scaffolding( pub(super) fn gen_method_scaffolding( sig: FnSignature, - arguments: &ExportAttributeArguments, + ar: &Option<AsyncRuntime>, udl_mode: bool, ) -> syn::Result<TokenStream> { let scaffolding_func = if sig.receiver.is_none() { @@ -75,7 +72,7 @@ pub(super) fn gen_method_scaffolding( "associated functions are not currently supported", )); } else { - gen_ffi_function(&sig, arguments, udl_mode)? + gen_ffi_function(&sig, ar, udl_mode)? }; let metadata_items = (!udl_mode).then(|| { @@ -90,31 +87,37 @@ pub(super) fn gen_method_scaffolding( // Pieces of code for the scaffolding function struct ScaffoldingBits { - /// Parameters for the scaffolding function - params: Vec<TokenStream>, + /// Parameter names for the scaffolding function + param_names: Vec<TokenStream>, + /// Parameter types for the scaffolding function + param_types: Vec<TokenStream>, /// Lift closure. See `FnSignature::lift_closure` for an explanation of this. lift_closure: TokenStream, /// Expression to call the Rust function after a successful lift. rust_fn_call: TokenStream, + /// Convert the result of `rust_fn_call`, stored in a variable named `uniffi_result` into its final value. + /// This is used to do things like error conversion / Arc wrapping + convert_result: TokenStream, } impl ScaffoldingBits { fn new_for_function(sig: &FnSignature, udl_mode: bool) -> Self { let ident = &sig.ident; - let params: Vec<_> = sig.args.iter().map(NamedArg::scaffolding_param).collect(); let call_params = sig.rust_call_params(false); let rust_fn_call = quote! { #ident(#call_params) }; // UDL mode adds an extra conversion (#1749) - let rust_fn_call = if udl_mode && sig.looks_like_result { - quote! { #rust_fn_call.map_err(::std::convert::Into::into) } + let convert_result = if udl_mode && sig.looks_like_result { + quote! { uniffi_result.map_err(::std::convert::Into::into) } } else { - rust_fn_call + quote! { uniffi_result } }; Self { - params, + param_names: sig.scaffolding_param_names().collect(), + param_types: sig.scaffolding_param_types().collect(), lift_closure: sig.lift_closure(None), rust_fn_call, + convert_result, } } @@ -125,20 +128,32 @@ impl ScaffoldingBits { udl_mode: bool, ) -> Self { let ident = &sig.ident; - let ffi_converter = if is_trait { + let lift_impl = if is_trait { quote! { - <::std::sync::Arc<dyn #self_ident> as ::uniffi::FfiConverter<crate::UniFfiTag>> + <::std::sync::Arc<dyn #self_ident> as ::uniffi::Lift<crate::UniFfiTag>> } } else { quote! { - <::std::sync::Arc<#self_ident> as ::uniffi::FfiConverter<crate::UniFfiTag>> + <::std::sync::Arc<#self_ident> as ::uniffi::Lift<crate::UniFfiTag>> } }; - let params: Vec<_> = iter::once(quote! { uniffi_self_lowered: #ffi_converter::FfiType }) - .chain(sig.scaffolding_params()) - .collect(); + let try_lift_self = if is_trait { + // For trait interfaces we need to special case this. Trait interfaces normally lift + // foreign trait impl pointers. However, for a method call, we want to lift a Rust + // pointer. + quote! { + { + let boxed_foreign_arc = unsafe { Box::from_raw(uniffi_self_lowered as *mut ::std::sync::Arc<dyn #self_ident>) }; + // Take a clone for our own use. + Ok(*boxed_foreign_arc) + } + } + } else { + quote! { #lift_impl::try_lift(uniffi_self_lowered) } + }; + let lift_closure = sig.lift_closure(Some(quote! { - match #ffi_converter::try_lift(uniffi_self_lowered) { + match #try_lift_self { Ok(v) => v, Err(e) => return Err(("self", e)) } @@ -146,38 +161,45 @@ impl ScaffoldingBits { let call_params = sig.rust_call_params(true); let rust_fn_call = quote! { uniffi_args.0.#ident(#call_params) }; // UDL mode adds an extra conversion (#1749) - let rust_fn_call = if udl_mode && sig.looks_like_result { - quote! { #rust_fn_call.map_err(::std::convert::Into::into) } + let convert_result = if udl_mode && sig.looks_like_result { + quote! { uniffi_result .map_err(::std::convert::Into::into) } } else { - rust_fn_call + quote! { uniffi_result } }; Self { - params, + param_names: iter::once(quote! { uniffi_self_lowered }) + .chain(sig.scaffolding_param_names()) + .collect(), + param_types: iter::once(quote! { #lift_impl::FfiType }) + .chain(sig.scaffolding_param_types()) + .collect(), lift_closure, rust_fn_call, + convert_result, } } fn new_for_constructor(sig: &FnSignature, self_ident: &Ident, udl_mode: bool) -> Self { let ident = &sig.ident; - let params: Vec<_> = sig.args.iter().map(NamedArg::scaffolding_param).collect(); let call_params = sig.rust_call_params(false); let rust_fn_call = quote! { #self_ident::#ident(#call_params) }; // UDL mode adds extra conversions (#1749) - let rust_fn_call = match (udl_mode, sig.looks_like_result) { + let convert_result = match (udl_mode, sig.looks_like_result) { // For UDL - (true, false) => quote! { ::std::sync::Arc::new(#rust_fn_call) }, + (true, false) => quote! { ::std::sync::Arc::new(uniffi_result) }, (true, true) => { - quote! { #rust_fn_call.map(::std::sync::Arc::new).map_err(::std::convert::Into::into) } + quote! { uniffi_result.map(::std::sync::Arc::new).map_err(::std::convert::Into::into) } } - (false, _) => rust_fn_call, + (false, _) => quote! { uniffi_result }, }; Self { - params, + param_names: sig.scaffolding_param_names().collect(), + param_types: sig.scaffolding_param_types().collect(), lift_closure: sig.lift_closure(None), rust_fn_call, + convert_result, } } } @@ -188,13 +210,15 @@ impl ScaffoldingBits { /// `rust_fn` is the Rust function to call. pub(super) fn gen_ffi_function( sig: &FnSignature, - arguments: &ExportAttributeArguments, + ar: &Option<AsyncRuntime>, udl_mode: bool, ) -> syn::Result<TokenStream> { let ScaffoldingBits { - params, + param_names, + param_types, lift_closure, rust_fn_call, + convert_result, } = match &sig.kind { FnKind::Function => ScaffoldingBits::new_for_function(sig, udl_mode), FnKind::Method { self_ident } => { @@ -216,14 +240,15 @@ pub(super) fn gen_ffi_function( let ffi_ident = sig.scaffolding_fn_ident()?; let name = &sig.name; - let return_impl = &sig.return_impl(); + let return_ty = &sig.return_ty; + let return_impl = &sig.lower_return_impl(); Ok(if !sig.is_async { quote! { #[doc(hidden)] #[no_mangle] #vis extern "C" fn #ffi_ident( - #(#params,)* + #(#param_names: #param_types,)* call_status: &mut ::uniffi::RustCallStatus, ) -> #return_impl::ReturnType { ::uniffi::deps::log::debug!(#name); @@ -231,7 +256,10 @@ pub(super) fn gen_ffi_function( ::uniffi::rust_call(call_status, || { #return_impl::lower_return( match uniffi_lift_args() { - Ok(uniffi_args) => #rust_fn_call, + Ok(uniffi_args) => { + let uniffi_result = #rust_fn_call; + #convert_result + } Err((arg_name, anyhow_error)) => { #return_impl::handle_failed_lift(arg_name, anyhow_error) }, @@ -242,25 +270,28 @@ pub(super) fn gen_ffi_function( } } else { let mut future_expr = rust_fn_call; - if matches!(arguments.async_runtime, Some(AsyncRuntime::Tokio(_))) { + if matches!(ar, Some(AsyncRuntime::Tokio(_))) { future_expr = quote! { ::uniffi::deps::async_compat::Compat::new(#future_expr) } } quote! { #[doc(hidden)] #[no_mangle] - pub extern "C" fn #ffi_ident(#(#params,)*) -> ::uniffi::RustFutureHandle { + pub extern "C" fn #ffi_ident(#(#param_names: #param_types,)*) -> ::uniffi::Handle { ::uniffi::deps::log::debug!(#name); let uniffi_lift_args = #lift_closure; match uniffi_lift_args() { Ok(uniffi_args) => { - ::uniffi::rust_future_new( - async move { #future_expr.await }, + ::uniffi::rust_future_new::<_, #return_ty, _>( + async move { + let uniffi_result = #future_expr.await; + #convert_result + }, crate::UniFfiTag ) }, Err((arg_name, anyhow_error)) => { - ::uniffi::rust_future_new( + ::uniffi::rust_future_new::<_, #return_ty, _>( async move { #return_impl::handle_failed_lift(arg_name, anyhow_error) }, |