From a1764f7690cfdc3e42724fcad29ef954b7e576a4 Mon Sep 17 00:00:00 2001
From: Matt Mastracci <matthew@mastracci.com>
Date: Tue, 4 Apr 2023 06:46:31 -0600
Subject: 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.
---
 runtime/build.rs      |  2 +-
 runtime/web_worker.rs | 13 ++++++++-----
 runtime/worker.rs     | 17 ++++++++++-------
 3 files changed, 19 insertions(+), 13 deletions(-)

(limited to 'runtime')

diff --git a/runtime/build.rs b/runtime/build.rs
index 809e32a76..eb8cc34a6 100644
--- a/runtime/build.rs
+++ b/runtime/build.rs
@@ -42,7 +42,7 @@ mod startup_snapshot {
 
     let parsed = deno_ast::parse_module(ParseParams {
       specifier: file_source.specifier.to_string(),
-      text_info: SourceTextInfo::from_string(code.take_as_string()),
+      text_info: SourceTextInfo::from_string(code.as_str().to_owned()),
       media_type,
       capture_tokens: false,
       scope_analysis: false,
diff --git a/runtime/web_worker.rs b/runtime/web_worker.rs
index 8bd5cf21e..4be40c9b0 100644
--- a/runtime/web_worker.rs
+++ b/runtime/web_worker.rs
@@ -9,6 +9,7 @@ use crate::BootstrapOptions;
 use deno_broadcast_channel::InMemoryBroadcastChannel;
 use deno_cache::CreateCache;
 use deno_cache::SqliteBackedCache;
+use deno_core::ascii_str;
 use deno_core::error::AnyError;
 use deno_core::error::JsError;
 use deno_core::futures::channel::mpsc;
@@ -572,11 +573,13 @@ impl WebWorker {
     // TODO(bartlomieju): this could be done using V8 API, without calling `execute_script`.
     // Save a reference to function that will start polling for messages
     // from a worker host; it will be called after the user code is loaded.
-    let script = r#"
+    let script = ascii_str!(
+      r#"
     const pollForMessages = globalThis.pollForMessages;
     delete globalThis.pollForMessages;
     pollForMessages
-    "#;
+    "#
+    );
     let poll_for_messages_fn = self
       .js_runtime
       .execute_script(located_script_name!(), script)
@@ -585,10 +588,10 @@ impl WebWorker {
   }
 
   /// See [JsRuntime::execute_script](deno_core::JsRuntime::execute_script)
-  pub fn execute_script<S: Into<ModuleCode>>(
+  pub fn execute_script(
     &mut self,
     name: &'static str,
-    source_code: S,
+    source_code: ModuleCode,
   ) -> Result<(), AnyError> {
     self.js_runtime.execute_script(name, source_code)?;
     Ok(())
@@ -777,7 +780,7 @@ pub fn run_web_worker(
 
     // Execute provided source code immediately
     let result = if let Some(source_code) = maybe_source_code.take() {
-      let r = worker.execute_script(located_script_name!(), source_code);
+      let r = worker.execute_script(located_script_name!(), source_code.into());
       worker.start_polling_for_messages();
       r
     } else {
diff --git a/runtime/worker.rs b/runtime/worker.rs
index 48bf7b09f..ea1e5e046 100644
--- a/runtime/worker.rs
+++ b/runtime/worker.rs
@@ -11,6 +11,7 @@ use std::task::Poll;
 use deno_broadcast_channel::InMemoryBroadcastChannel;
 use deno_cache::CreateCache;
 use deno_cache::SqliteBackedCache;
+use deno_core::ascii_str;
 use deno_core::error::AnyError;
 use deno_core::error::JsError;
 use deno_core::futures::Future;
@@ -370,10 +371,10 @@ impl MainWorker {
   }
 
   /// See [JsRuntime::execute_script](deno_core::JsRuntime::execute_script)
-  pub fn execute_script<S: Into<ModuleCode>>(
+  pub fn execute_script(
     &mut self,
     script_name: &'static str,
-    source_code: S,
+    source_code: ModuleCode,
   ) -> Result<v8::Global<v8::Value>, AnyError> {
     self.js_runtime.execute_script(script_name, source_code)
   }
@@ -510,12 +511,12 @@ impl MainWorker {
     &mut self,
     script_name: &'static str,
   ) -> Result<(), AnyError> {
-    self.execute_script(
+    self.js_runtime.execute_script(
       script_name,
       // NOTE(@bartlomieju): not using `globalThis` here, because user might delete
       // it. Instead we're using global `dispatchEvent` function which will
       // used a saved reference to global scope.
-      "dispatchEvent(new Event('load'))",
+      ascii_str!("dispatchEvent(new Event('load'))"),
     )?;
     Ok(())
   }
@@ -527,12 +528,12 @@ impl MainWorker {
     &mut self,
     script_name: &'static str,
   ) -> Result<(), AnyError> {
-    self.execute_script(
+    self.js_runtime.execute_script(
       script_name,
       // NOTE(@bartlomieju): not using `globalThis` here, because user might delete
       // it. Instead we're using global `dispatchEvent` function which will
       // used a saved reference to global scope.
-      "dispatchEvent(new Event('unload'))",
+      ascii_str!("dispatchEvent(new Event('unload'))"),
     )?;
     Ok(())
   }
@@ -549,7 +550,9 @@ impl MainWorker {
       // NOTE(@bartlomieju): not using `globalThis` here, because user might delete
       // it. Instead we're using global `dispatchEvent` function which will
       // used a saved reference to global scope.
-      "dispatchEvent(new Event('beforeunload', { cancelable: true }));",
+      ascii_str!(
+        "dispatchEvent(new Event('beforeunload', { cancelable: true }));"
+      ),
     )?;
     let local_value = value.open(&mut self.js_runtime.handle_scope());
     Ok(local_value.is_false())
-- 
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