refactor(core): Improve ergonomics of managing ASCII strings (#18498)

This is a follow-on to the earlier work in reducing string copies,
mainly focused on ensuring that ASCII strings are easy to provide to the
JS runtime.

While we are replacing a 16-byte reference in a number of places with a
24-byte structure (measured via `std::mem::size_of`), the reduction in
copies wins out over the additional size of the arguments passed into
functions.

Benchmarking shows approximately the same if not slightly less wallclock
time/instructions retired, but I believe this continues to open up
further refactoring opportunities.

1 files changed, 11 insertions, 10 deletions

diff --git a/core/examples/ts_module_loader.rs b/core/examples/ts_module_loader.rs
index 4a38073ab..6adb27977 100644
--- a/core/examples/ts_module_loader.rs
+++ b/core/examples/ts_module_loader.rs
@@ -14,6 +14,7 @@ use anyhow::Error;
 use deno_ast::MediaType;
 use deno_ast::ParseParams;
 use deno_ast::SourceTextInfo;
+use deno_core::error::AnyError;
 use deno_core::resolve_import;
 use deno_core::resolve_path;
 use deno_core::JsRuntime;
@@ -41,11 +42,12 @@ impl ModuleLoader for TypescriptModuleLoader {
   fn load(
     &self,
     module_specifier: &ModuleSpecifier,
-    _maybe_referrer: Option<ModuleSpecifier>,
+    _maybe_referrer: Option<&ModuleSpecifier>,
     _is_dyn_import: bool,
   ) -> Pin<Box<ModuleSourceFuture>> {
-    let module_specifier = module_specifier.clone();
-    async move {
+    fn load(
+      module_specifier: &ModuleSpecifier,
+    ) -> Result<ModuleSource, AnyError> {
       let path = module_specifier
         .to_file_path()
         .map_err(|_| anyhow!("Only file:// URLs are supported."))?;
@@ -81,15 +83,14 @@ impl ModuleLoader for TypescriptModuleLoader {
       } else {
         code
       };
-      let module = ModuleSource {
-        code: code.into(),
+      Ok(ModuleSource::new(
         module_type,
-        module_url_specified: module_specifier.to_string(),
-        module_url_found: module_specifier.to_string(),
-      };
-      Ok(module)
+        code.into(),
+        module_specifier,
+      ))
     }
-    .boxed_local()
+
+    futures::future::ready(load(module_specifier)).boxed_local()
   }
 }