Async IDC: rust outbox macro

crates/bindings-macro/src/lib.rs

@@ -159,6 +159,10 @@ mod sym {
     symbol!(repr);
     symbol!(sats);
     symbol!(scheduled);
+    symbol!(outbox);
+    symbol!(on_result);
+    symbol!(param);
+    symbol!(target);
     symbol!(unique);
     symbol!(update);
     symbol!(default);
@@ -229,7 +233,10 @@ fn derive_table_helper_attr() -> Attribute {
 ///
 /// Provides helper attributes for `#[spacetimedb::table]`, so that we don't get unknown attribute errors.
 #[doc(hidden)]
-#[proc_macro_derive(__TableHelper, attributes(sats, unique, auto_inc, primary_key, index, default))]
+#[proc_macro_derive(
+    __TableHelper,
+    attributes(sats, unique, auto_inc, primary_key, target, index, default, param)
+)]
 pub fn table_helper(input: StdTokenStream) -> StdTokenStream {
     schema_type(input)
 }

crates/bindings-macro/src/reducer.rs

@@ -10,6 +10,7 @@ use syn::{FnArg, Ident, ItemFn, LitStr, PatType};
 pub(crate) struct ReducerArgs {
     name: Option<LitStr>,
     lifecycle: Option<LifecycleReducer>,
+    on_result: Option<syn::Path>,
 }
 
 enum LifecycleReducer {
@@ -51,6 +52,12 @@ impl ReducerArgs {
                     check_duplicate(&args.name, &meta)?;
                     args.name = Some(meta.value()?.parse()?);
                 }
+                sym::on_result => {
+                    check_duplicate(&args.on_result, &meta)?;
+                    let content;
+                    syn::parenthesized!(content in meta.input);
+                    args.on_result = Some(content.parse()?);
+                }
             });
             Ok(())
         })
@@ -101,6 +108,19 @@ pub(crate) fn reducer_impl(args: ReducerArgs, original_function: &ItemFn) -> syn
     assert_only_lifetime_generics(original_function, "reducers")?;
 
     let lifecycle = args.lifecycle.iter().filter_map(|lc| lc.to_lifecycle_value());
+    let on_result_outbox = args.on_result.as_ref().map(|path| {
+        let accessor = &path.segments.last().unwrap().ident;
+        quote!(
+            const ON_RESULT_OUTBOX: Option<&'static str> =
+                Some(spacetimedb::rt::on_result_outbox(#path::#accessor));
+        )
+    });
+    let on_result_typecheck = args.on_result.as_ref().map(|path| {
+        let accessor = &path.segments.last().unwrap().ident;
+        quote! {
+            spacetimedb::rt::on_result_typecheck(#func_name, #path::#accessor);
+        }
+    });
 
     let typed_args = extract_typed_args(original_function)?;
 
@@ -156,6 +176,7 @@ pub(crate) fn reducer_impl(args: ReducerArgs, original_function: &ItemFn) -> syn
                 #(let _ = <#first_arg_ty as spacetimedb::rt::ReducerContextArg>::_ITEM;)*
                 #(let _ = <#rest_arg_tys as spacetimedb::rt::ReducerArg>::_ITEM;)*
                 #(let _ = <#ret_ty as spacetimedb::rt::IntoReducerResult>::into_result;)*
+                #on_result_typecheck
             }
         };
         impl #func_name {
@@ -170,6 +191,7 @@ pub(crate) fn reducer_impl(args: ReducerArgs, original_function: &ItemFn) -> syn
             type FnKind = spacetimedb::rt::FnKindReducer;
             const NAME: &'static str = #reducer_name;
             #(const LIFECYCLE: Option<spacetimedb::rt::LifecycleReducer> = Some(#lifecycle);)*
+            #on_result_outbox
             const ARG_NAMES: &'static [Option<&'static str>] = &[#(#opt_arg_names),*];
             const INVOKE: Self::Invoke = #func_name::invoke;
         }