feat(ops): infallible / result-free ops (denoland#14585)

core/ops_builtin.rs

@@ -43,26 +43,19 @@ pub(crate) fn init_builtins() -> Extension {
 /// Return map of resources with id as key
 /// and string representation as value.
 #[op]
-pub fn op_resources(
- state: &mut OpState,
-) -> Result<Vec<(ResourceId, String)>, Error> {
- let serialized_resources = state
+pub fn op_resources(state: &mut OpState) -> Vec<(ResourceId, String)> {
+ state
  .resource_table
  .names()
  .map(|(rid, name)| (rid, name.to_string()))
- .collect();
- Ok(serialized_resources)
+ .collect()
 }
 
 #[op]
-pub fn op_void_sync() -> Result<(), Error> {
- Ok(())
-}
+pub fn op_void_sync() {}
 
 #[op]
-pub async fn op_void_async() -> Result<(), Error> {
- Ok(())
-}
+pub async fn op_void_async() {}
 
 /// Remove a resource from the resource table.
 #[op]
@@ -92,12 +85,10 @@ pub fn op_try_close(
 }
 
 #[op]
-pub fn op_metrics(
- state: &mut OpState,
-) -> Result<(OpMetrics, Vec<OpMetrics>), Error> {
+pub fn op_metrics(state: &mut OpState) -> (OpMetrics, Vec<OpMetrics>) {
  let aggregate = state.tracker.aggregate();
  let per_op = state.tracker.per_op();
- Ok((aggregate, per_op))
+ (aggregate, per_op)
 }
 
 /// Builtin utility to print to stdout/stderr
@@ -187,6 +178,6 @@ async fn op_shutdown(
 }
 
 #[op]
-fn op_format_file_name(file_name: String) -> Result<String, Error> {
- Ok(format_file_name(&file_name))
+fn op_format_file_name(file_name: String) -> String {
+ format_file_name(&file_name)
 }

ops/lib.rs

@@ -154,6 +154,11 @@ fn codegen_v8_async(
  let (arg_decls, args_tail) = codegen_args(core, f, rust_i0, 1);
  let type_params = &f.sig.generics.params;
 
+ let result_wrapper = match is_result(&f.sig.output) {
+ true => quote! {},
+ false => quote! { let result = Ok(result); },
+ };
+
  quote! {
  use #core::futures::FutureExt;
  // SAFETY: #core guarantees args.data() is a v8 External pointing to an OpCtx for the isolates lifetime
@@ -189,6 +194,7 @@ fn codegen_v8_async(
 
  #core::_ops::queue_async_op(scope, async move {
  let result = Self::call::<#type_params>(#args_head #args_tail).await;
+ #result_wrapper
  (promise_id, op_id, #core::_ops::to_op_result(get_class, result))
  });
  }
@@ -325,7 +331,14 @@ fn codegen_sync_ret(
  }
  };
 
+ let result_wrapper = match is_result(&**ret_type) {
+ true => quote! {},
+ false => quote! { let result = Ok(result); },
+ };
+
  quote! {
+ #result_wrapper
+
  match result {
  Ok(v) => {
  #ok_block
@@ -338,6 +351,19 @@ fn codegen_sync_ret(
  }
 }
 
+fn is_result(ty: impl ToTokens) -> bool {
+ let tokens = tokens(ty);
+ if tokens.trim_start_matches("-> ").starts_with("Result <") {
+ return true;
+ }
+ // Detect `io::Result<...>`, `anyhow::Result<...>`, etc...
+ // i.e: Result aliases/shorthands which are unfortunately "opaque" at macro-time
+ match tokens.find(":: Result <") {
+ Some(idx) => !tokens.split_at(idx).0.contains('<'),
+ None => false,
+ }
+}
+
 /// Detects if a type is of the form Result<(), Err>
 fn is_unit_result(ty: &syn::Type) -> bool {
  let path = match ty {