refactor(ops): op2 supports strings in argument and return position (#19613)

Support strings (&str, String, and Cow) in the argument position and String in the return position. Avoids
copies where possible, though this is not always something we can do.

1 files changed, 12 insertions, 0 deletions

diff --git a/ops/op2/signature.rs b/ops/op2/signature.rs
index 15c40e007..5d472fcf3 100644
--- a/ops/op2/signature.rs
+++ b/ops/op2/signature.rs
@@ -106,6 +106,7 @@ pub enum Special {
   HandleScope,
   OpState,
   String,
+  CowStr,
   RefStr,
   FastApiCallbackOptions,
 }
@@ -431,6 +432,17 @@ fn parse_type_path(attrs: Attributes, tp: &TypePath) -> Result<Arg, ArgError> {
           Err(ArgError::MissingStringAttribute)
         }
       }
+      ( $( std :: str  :: )? str ) => {
+        // We should not hit this path with a #[string] argument
+        Err(ArgError::MissingStringAttribute)
+      }
+      ( $( std :: borrow :: )? Cow < str > ) => {
+        if attrs.primary == Some(AttributeModifier::String) {
+          Ok(Arg::Special(Special::CowStr))
+        } else {
+          Err(ArgError::MissingStringAttribute)
+        }
+      }
       ( $( std :: ffi :: )? c_void ) => Ok(Arg::Numeric(NumericArg::__VOID__)),
       ( OpState ) => Ok(Arg::Special(Special::OpState)),
       ( v8 :: HandleScope ) => Ok(Arg::Special(Special::HandleScope)),