refactor(lsp): Have JS drive TSC event loop in LSP (#23565)

1 files changed, 57 insertions, 0 deletions

diff --git a/cli/util/v8/convert.rs b/cli/util/v8/convert.rs
new file mode 100644
index 000000000..28107d901
--- /dev/null
+++ b/cli/util/v8/convert.rs
@@ -0,0 +1,57 @@
+// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
+
+use deno_core::v8;
+use deno_core::FromV8;
+use deno_core::ToV8;
+
+#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+/// A wrapper type for `Option<T>` that (de)serializes `None` as `null`
+#[repr(transparent)]
+pub struct OptionNull<T>(pub Option<T>);
+
+impl<T> From<Option<T>> for OptionNull<T> {
+  fn from(option: Option<T>) -> Self {
+    Self(option)
+  }
+}
+
+impl<T> From<OptionNull<T>> for Option<T> {
+  fn from(value: OptionNull<T>) -> Self {
+    value.0
+  }
+}
+
+impl<'a, T> ToV8<'a> for OptionNull<T>
+where
+  T: ToV8<'a>,
+{
+  type Error = T::Error;
+
+  fn to_v8(
+    self,
+    scope: &mut v8::HandleScope<'a>,
+  ) -> Result<v8::Local<'a, v8::Value>, Self::Error> {
+    match self.0 {
+      Some(value) => value.to_v8(scope),
+      None => Ok(v8::null(scope).into()),
+    }
+  }
+}
+
+impl<'a, T> FromV8<'a> for OptionNull<T>
+where
+  T: FromV8<'a>,
+{
+  type Error = T::Error;
+
+  fn from_v8(
+    scope: &mut v8::HandleScope<'a>,
+    value: v8::Local<'a, v8::Value>,
+  ) -> Result<Self, Self::Error> {
+    if value.is_null() {
+      Ok(OptionNull(None))
+    } else {
+      T::from_v8(scope, value).map(|v| OptionNull(Some(v)))
+    }
+  }
+}