fix(lsp): correct positions in some scenarios (#14359)

7 files changed, 96 insertions, 533 deletions

diff --git a/cli/build.rs b/cli/build.rs
index 019f8d02d..e7a2da236 100644
--- a/cli/build.rs
+++ b/cli/build.rs
@@ -198,6 +198,14 @@ fn create_compiler_snapshot(
   }
 
   #[op]
+  fn op_script_version(
+    _state: &mut OpState,
+    _args: Value,
+  ) -> Result<Option<String>, AnyError> {
+    Ok(Some("1".to_string()))
+  }
+
+  #[op]
   // using the same op that is used in `tsc.rs` for loading modules and reading
   // files, but a slightly different implementation at build time.
   fn op_load(state: &mut OpState, args: LoadArgs) -> Result<Value, AnyError> {
@@ -211,7 +219,7 @@ fn create_compiler_snapshot(
     if args.specifier == build_specifier {
       Ok(json!({
         "data": r#"console.log("hello deno!");"#,
-        "hash": "1",
+        "version": "1",
         // this corresponds to `ts.ScriptKind.TypeScript`
         "scriptKind": 3
       }))
@@ -230,7 +238,7 @@ fn create_compiler_snapshot(
         let data = std::fs::read_to_string(path)?;
         Ok(json!({
           "data": data,
-          "hash": "1",
+          "version": "1",
           // this corresponds to `ts.ScriptKind.TypeScript`
           "scriptKind": 3
         }))
@@ -255,6 +263,7 @@ fn create_compiler_snapshot(
         op_cwd::decl(),
         op_exists::decl(),
         op_load::decl(),
+        op_script_version::decl(),
       ])
       .state(move |state| {
         state.put(op_crate_libs.clone());
diff --git a/cli/lsp/documents.rs b/cli/lsp/documents.rs
index 0a383e781..4fb8c428e 100644
--- a/cli/lsp/documents.rs
+++ b/cli/lsp/documents.rs
@@ -200,6 +200,13 @@ impl AssetOrDocument {
     }
   }
 
+  pub fn media_type(&self) -> MediaType {
+    match self {
+      AssetOrDocument::Asset(_) => MediaType::TypeScript, // assets are always TypeScript
+      AssetOrDocument::Document(d) => d.media_type(),
+    }
+  }
+
   pub fn get_maybe_dependency(
     &self,
     position: &lsp::Position,
diff --git a/cli/lsp/text.rs b/cli/lsp/text.rs
index 64721ebc7..33ac2048f 100644
--- a/cli/lsp/text.rs
+++ b/cli/lsp/text.rs
@@ -2,13 +2,9 @@
 
 use deno_core::error::custom_error;
 use deno_core::error::AnyError;
-use deno_core::serde_json::json;
-use deno_core::serde_json::Value;
 use dissimilar::diff;
 use dissimilar::Chunk;
 use std::collections::HashMap;
-use std::ops::Bound;
-use std::ops::RangeBounds;
 use text_size::TextRange;
 use text_size::TextSize;
 use tower_lsp::jsonrpc;
@@ -261,112 +257,6 @@ pub fn get_edits(a: &str, b: &str, line_index: &LineIndex) -> Vec<TextEdit> {
   text_edits
 }
 
-/// Convert a difference between two strings into a change range used by the
-/// TypeScript Language Service.
-pub fn get_range_change(a: &str, b: &str) -> Value {
-  if a == b {
-    return json!(null);
-  }
-  let chunks = diff(a, b);
-  let mut iter = chunks.iter().peekable();
-  let mut started = false;
-  let mut start = 0;
-  let mut end = 0;
-  let mut new_length = 0;
-  let mut equal = 0;
-  let mut a_pos = 0;
-  loop {
-    let diff = iter.next();
-    match diff {
-      None => break,
-      Some(Chunk::Equal(e)) => {
-        a_pos += e.encode_utf16().count();
-        equal += e.encode_utf16().count();
-      }
-      Some(Chunk::Delete(d)) => {
-        if !started {
-          start = a_pos;
-          started = true;
-          equal = 0;
-        }
-        a_pos += d.encode_utf16().count();
-        if started {
-          end = a_pos;
-          new_length += equal;
-          equal = 0;
-        }
-      }
-      Some(Chunk::Insert(i)) => {
-        if !started {
-          start = a_pos;
-          end = a_pos;
-          started = true;
-          equal = 0;
-        } else {
-          end += equal;
-        }
-        new_length += i.encode_utf16().count() + equal;
-        equal = 0;
-      }
-    }
-  }
-
-  json!({
-    "span": {
-      "start": start,
-      "length": end - start,
-    },
-    "newLength": new_length,
-  })
-}
-
-/// Provide a slice of a string based on a character range.
-pub fn slice(s: &str, range: impl RangeBounds<usize>) -> &str {
-  let start = match range.start_bound() {
-    Bound::Included(bound) | Bound::Excluded(bound) => *bound,
-    Bound::Unbounded => 0,
-  };
-  let len = match range.end_bound() {
-    Bound::Included(bound) => *bound + 1,
-    Bound::Excluded(bound) => *bound,
-    Bound::Unbounded => s.encode_utf16().count(),
-  } - start;
-  substring(s, start, start + len)
-}
-
-/// Provide a substring based on the start and end character index positions.
-pub fn substring(s: &str, start: usize, end: usize) -> &str {
-  let len = end - start;
-  let mut char_pos = 0;
-  let mut byte_start = 0;
-  let mut it = s.chars();
-  loop {
-    if char_pos == start {
-      break;
-    }
-    if let Some(c) = it.next() {
-      char_pos += c.len_utf16();
-      byte_start += c.len_utf8();
-    } else {
-      break;
-    }
-  }
-  char_pos = 0;
-  let mut byte_end = byte_start;
-  loop {
-    if char_pos == len {
-      break;
-    }
-    if let Some(c) = it.next() {
-      char_pos += c.len_utf16();
-      byte_end += c.len_utf8();
-    } else {
-      break;
-    }
-  }
-  &s[byte_start..byte_end]
-}
-
 #[cfg(test)]
 mod tests {
   use super::*;
@@ -637,155 +527,4 @@ const C: char = \"メ メ\";
       ]
     )
   }
-
-  #[test]
-  fn test_get_range_change() {
-    let a = "abcdefg";
-    let b = "abcdefg";
-    let actual = get_range_change(a, b);
-    assert_eq!(actual, json!(null));
-
-    let a = "abcdefg";
-    let b = "abedcfg";
-    let actual = get_range_change(a, b);
-    assert_eq!(
-      actual,
-      json!({
-        "span": {
-          "start": 2,
-          "length": 3,
-        },
-        "newLength": 3
-      })
-    );
-
-    let a = "abfg";
-    let b = "abcdefg";
-    let actual = get_range_change(a, b);
-    assert_eq!(
-      actual,
-      json!({
-        "span": {
-          "start": 2,
-          "length": 0,
-        },
-        "newLength": 3
-      })
-    );
-
-    let a = "abcdefg";
-    let b = "abfg";
-    let actual = get_range_change(a, b);
-    assert_eq!(
-      actual,
-      json!({
-        "span": {
-          "start": 2,
-          "length": 3,
-        },
-        "newLength": 0
-      })
-    );
-
-    let a = "abcdefg";
-    let b = "abfghij";
-    let actual = get_range_change(a, b);
-    assert_eq!(
-      actual,
-      json!({
-        "span": {
-          "start": 2,
-          "length": 5,
-        },
-        "newLength": 5
-      })
-    );
-
-    let a = "abcdefghijk";
-    let b = "axcxexfxixk";
-    let actual = get_range_change(a, b);
-    assert_eq!(
-      actual,
-      json!({
-        "span": {
-          "start": 1,
-          "length": 9,
-        },
-        "newLength": 9
-      })
-    );
-
-    let a = "abcde";
-    let b = "ab(c)de";
-    let actual = get_range_change(a, b);
-    assert_eq!(
-      actual,
-      json!({
-        "span" : {
-          "start": 2,
-          "length": 1,
-        },
-        "newLength": 3
-      })
-    );
-
-    let a = "hello 🦕!";
-    let b = "hello deno!";
-    let actual = get_range_change(a, b);
-    assert_eq!(
-      actual,
-      json!({
-        "span": {
-          "start": 6,
-          "length": 2,
-        },
-        "newLength": 4
-      })
-    );
-
-    let a = "hello deno!";
-    let b = "hello deno🦕!";
-    let actual = get_range_change(a, b);
-    assert_eq!(
-      actual,
-      json!({
-        "span": {
-          "start": 10,
-          "length": 0,
-        },
-        "newLength": 2
-      })
-    );
-
-    // TODO(@kitsonk): https://github.com/dtolnay/dissimilar/issues/5
-    // let a = r#" 🦕🇺🇸👍 "#;
-    // let b = r#" 🇺🇸👍 "#;
-    // let actual = get_range_change(a, b);
-    // assert_eq!(
-    //   actual,
-    //   json!({
-    //     "span": {
-    //       "start": 1,
-    //       "length": 2,
-    //     },
-    //     "newLength": 0
-    //   })
-    // );
-  }
-
-  #[test]
-  fn test_substring() {
-    assert_eq!(substring("Deno", 1, 3), "en");
-    assert_eq!(substring("y̆y̆", 2, 4), "y̆");
-    assert_eq!(substring("🦕🦕", 2, 4), "🦕");
-  }
-
-  #[test]
-  fn test_slice() {
-    assert_eq!(slice("Deno", 1..3), "en");
-    assert_eq!(slice("Deno", 1..=3), "eno");
-    assert_eq!(slice("Deno Land", 1..), "eno Land");
-    assert_eq!(slice("Deno", ..3), "Den");
-    assert_eq!(slice("Hello 🦕", 6..8), "🦕");
-  }
 }
diff --git a/cli/lsp/tsc.rs b/cli/lsp/tsc.rs
index 27d32b2db..1448c8c96 100644
--- a/cli/lsp/tsc.rs
+++ b/cli/lsp/tsc.rs
@@ -13,7 +13,6 @@ use super::refactor::EXTRACT_INTERFACE;
 use super::refactor::EXTRACT_TYPE;
 use super::semantic_tokens;
 use super::semantic_tokens::SemanticTokensBuilder;
-use super::text;
 use super::text::LineIndex;
 use super::urls::LspUrlMap;
 use super::urls::INVALID_SPECIFIER;
@@ -47,7 +46,6 @@ use log::warn;
 use once_cell::sync::Lazy;
 use regex::Captures;
 use regex::Regex;
-use std::borrow::Cow;
 use std::cmp;
 use std::collections::HashMap;
 use std::collections::HashSet;
@@ -157,7 +155,6 @@ impl TsServer {
 struct AssetDocumentInner {
   specifier: ModuleSpecifier,
   text: Arc<String>,
-  length: usize,
   line_index: Arc<LineIndex>,
   maybe_navigation_tree: Option<Arc<NavigationTree>>,
 }
@@ -173,7 +170,6 @@ impl AssetDocument {
     Self(Arc::new(AssetDocumentInner {
       specifier,
       text: Arc::new(text.to_string()),
-      length: text.encode_utf16().count(),
       line_index: Arc::new(LineIndex::new(text)),
       maybe_navigation_tree: None,
     }))
@@ -197,14 +193,6 @@ impl AssetDocument {
     self.0.text.clone()
   }
 
-  pub fn text_str(&self) -> &str {
-    self.0.text.as_str()
-  }
-
-  pub fn length(&self) -> usize {
-    self.0.length
-  }
-
   pub fn line_index(&self) -> Arc<LineIndex> {
     self.0.line_index.clone()
   }
@@ -2374,17 +2362,16 @@ struct Response {
   data: Value,
 }
 
-struct State<'a> {
+struct State {
   last_id: usize,
   performance: Arc<Performance>,
   response: Option<Response>,
   state_snapshot: Arc<StateSnapshot>,
-  snapshots: HashMap<(ModuleSpecifier, Cow<'a, str>), String>,
   specifiers: HashMap<String, String>,
   token: CancellationToken,
 }
 
-impl<'a> State<'a> {
+impl State {
   fn new(
     state_snapshot: Arc<StateSnapshot>,
     performance: Arc<Performance>,
@@ -2394,7 +2381,6 @@ impl<'a> State<'a> {
       performance,
       response: None,
       state_snapshot,
-      snapshots: HashMap::default(),
       specifiers: HashMap::default(),
       token: Default::default(),
     }
@@ -2426,31 +2412,37 @@ impl<'a> State<'a> {
     }
     ModuleSpecifier::parse(&specifier_str).map_err(|err| err.into())
   }
-}
 
-/// If a snapshot is missing from the state cache, add it.
-fn cache_snapshot(
-  state: &mut State,
-  specifier: &ModuleSpecifier,
-  version: String,
-) -> Result<(), AnyError> {
-  if !state
-    .snapshots
-    .contains_key(&(specifier.clone(), version.clone().into()))
-  {
-    let content = state
-      .state_snapshot
-      .documents
-      .get(specifier)
-      .ok_or_else(|| {
-        anyhow!("Specifier unexpectedly doesn't exist: {}", specifier)
-      })?
-      .content();
-    state
-      .snapshots
-      .insert((specifier.clone(), version.into()), content.to_string());
+  fn get_asset_or_document(
+    &self,
+    specifier: &ModuleSpecifier,
+  ) -> Option<AssetOrDocument> {
+    let snapshot = &self.state_snapshot;
+    if specifier.scheme() == "asset" {
+      snapshot.assets.get(specifier).map(AssetOrDocument::Asset)
+    } else {
+      snapshot
+        .documents
+        .get(specifier)
+        .map(AssetOrDocument::Document)
+    }
+  }
+
+  fn script_version(&self, specifier: &ModuleSpecifier) -> Option<String> {
+    if specifier.scheme() == "asset" {
+      if self.state_snapshot.assets.contains_key(specifier) {
+        Some("1".to_string())
+      } else {
+        None
+      }
+    } else {
+      self
+        .state_snapshot
+        .documents
+        .get(specifier)
+        .map(|d| d.script_version())
+    }
   }
-  Ok(())
 }
 
 fn normalize_specifier<S: AsRef<str>>(
@@ -2462,28 +2454,6 @@ fn normalize_specifier<S: AsRef<str>>(
 
 #[derive(Debug, Deserialize, Serialize)]
 #[serde(rename_all = "camelCase")]
-struct SourceSnapshotArgs {
-  specifier: String,
-  version: String,
-}
-
-/// The language service is dropping a reference to a source file snapshot, and
-/// we can drop our version of that document.
-#[op]
-fn op_dispose(
-  state: &mut OpState,
-  args: SourceSnapshotArgs,
-) -> Result<bool, AnyError> {
-  let state = state.borrow_mut::<State>();
-  let mark = state.performance.mark("op_dispose", Some(&args));
-  let specifier = state.normalize_specifier(&args.specifier)?;
-  state.snapshots.remove(&(specifier, args.version.into()));
-  state.performance.measure(mark);
-  Ok(true)
-}
-
-#[derive(Debug, Deserialize, Serialize)]
-#[serde(rename_all = "camelCase")]
 struct SpecifierArgs {
   specifier: String,
 }
@@ -2506,116 +2476,6 @@ fn op_exists(state: &mut OpState, args: SpecifierArgs) -> bool {
   state.state_snapshot.documents.exists(&specifier)
 }
 
-#[derive(Debug, Deserialize, Serialize)]
-#[serde(rename_all = "camelCase")]
-struct GetChangeRangeArgs {
-  specifier: String,
-  old_length: u32,
-  old_version: String,
-  version: String,
-}
-
-/// The language service wants to compare an old snapshot with a new snapshot to
-/// determine what source has changed.
-#[op]
-fn op_get_change_range(
-  state: &mut OpState,
-  args: GetChangeRangeArgs,
-) -> Result<Value, AnyError> {
-  let state = state.borrow_mut::<State>();
-  let mark = state.performance.mark("op_get_change_range", Some(&args));
-  let specifier = state.normalize_specifier(&args.specifier)?;
-  cache_snapshot(state, &specifier, args.version.clone())?;
-  let r = if let Some(current) = state
-    .snapshots
-    .get(&(specifier.clone(), args.version.clone().into()))
-  {
-    if let Some(prev) = state
-      .snapshots
-      .get(&(specifier, args.old_version.clone().into()))
-    {
-      Ok(text::get_range_change(prev, current))
-    } else {
-      let new_length = current.encode_utf16().count();
-      // when a local file is opened up in the editor, the compiler might
-      // already have a snapshot of it in memory, and will request it, but we
-      // now are working off in memory versions of the document, and so need
-      // to tell tsc to reset the whole document
-      Ok(json!({
-        "span": {
-          "start": 0,
-          "length": args.old_length,
-        },
-        "newLength": new_length,
-      }))
-    }
-  } else {
-    Err(custom_error(
-      "MissingSnapshot",
-      format!(
-        "The current snapshot version is missing.\n  Args: \"{:?}\"",
-        args
-      ),
-    ))
-  };
-
-  state.performance.measure(mark);
-  r
-}
-
-#[op]
-fn op_get_length(
-  state: &mut OpState,
-  args: SourceSnapshotArgs,
-) -> Result<usize, AnyError> {
-  let state = state.borrow_mut::<State>();
-  let mark = state.performance.mark("op_get_length", Some(&args));
-  let specifier = state.normalize_specifier(args.specifier)?;
-  let r = if let Some(asset) = state.state_snapshot.assets.get(&specifier) {
-    Ok(asset.length())
-  } else {
-    cache_snapshot(state, &specifier, args.version.clone())?;
-    let content = state
-      .snapshots
-      .get(&(specifier, args.version.into()))
-      .unwrap();
-    Ok(content.encode_utf16().count())
-  };
-  state.performance.measure(mark);
-  r
-}
-
-#[derive(Debug, Deserialize, Serialize)]
-#[serde(rename_all = "camelCase")]
-struct GetTextArgs {
-  specifier: String,
-  version: String,
-  start: usize,
-  end: usize,
-}
-
-#[op]
-fn op_get_text(
-  state: &mut OpState,
-  args: GetTextArgs,
-) -> Result<String, AnyError> {
-  let state = state.borrow_mut::<State>();
-  let mark = state.performance.mark("op_get_text", Some(&args));
-  let specifier = state.normalize_specifier(args.specifier)?;
-  let maybe_asset = state.state_snapshot.assets.get(&specifier);
-  let content = if let Some(content) = &maybe_asset {
-    content.text_str()
-  } else {
-    cache_snapshot(state, &specifier, args.version.clone())?;
-    state
-      .snapshots
-      .get(&(specifier, args.version.into()))
-      .unwrap()
-  };
-  state.performance.measure(mark);
-  Ok(text::slice(content, args.start..args.end).to_string())
-}
-
 #[op]
 fn op_is_cancelled(state: &mut OpState) -> bool {
   let state = state.borrow_mut::<State>();
@@ -2626,13 +2486,22 @@ fn op_is_cancelled(state: &mut OpState) -> bool {
 fn op_load(
   state: &mut OpState,
   args: SpecifierArgs,
-) -> Result<Option<String>, AnyError> {
+) -> Result<Value, AnyError> {
   let state = state.borrow_mut::<State>();
   let mark = state.performance.mark("op_load", Some(&args));
   let specifier = state.normalize_specifier(args.specifier)?;
-  let document = state.state_snapshot.documents.get(&specifier);
+  let asset_or_document = state.get_asset_or_document(&specifier);
   state.performance.measure(mark);
-  Ok(document.map(|d| d.content().to_string()))
+  Ok(match asset_or_document {
+    Some(doc) => {
+      json!({
+        "data": doc.text(),
+        "scriptKind": crate::tsc::as_ts_script_kind(&doc.media_type()),
+        "version": state.script_version(&specifier),
+      })
+    }
+    None => Value::Null,
+  })
 }
 
 #[op]
@@ -2705,20 +2574,7 @@ fn op_script_version(
   // this op is very "noisy" and measuring its performance is not useful, so we
   // don't measure it uniquely anymore.
   let specifier = state.normalize_specifier(args.specifier)?;
-  if specifier.scheme() == "asset" {
-    if state.state_snapshot.assets.contains_key(&specifier) {
-      Ok(Some("1".to_string()))
-    } else {
-      Ok(None)
-    }
-  } else {
-    let script_version = state
-      .state_snapshot
-      .documents
-      .get(&specifier)
-      .map(|d| d.script_version());
-    Ok(script_version)
-  }
+  Ok(state.script_version(&specifier))
 }
 
 /// Create and setup a JsRuntime based on a snapshot. It is expected that the
@@ -2735,11 +2591,7 @@ fn js_runtime(performance: Arc<Performance>) -> JsRuntime {
 fn init_extension(performance: Arc<Performance>) -> Extension {
   Extension::builder()
     .ops(vec![
-      op_dispose::decl(),
       op_exists::decl(),
-      op_get_change_range::decl(),
-      op_get_length::decl(),
-      op_get_text::decl(),
       op_is_cancelled::decl(),
       op_load::decl(),
       op_resolve::decl(),
diff --git a/cli/tests/integration/lsp_tests.rs b/cli/tests/integration/lsp_tests.rs
index 08554bac8..be2283080 100644
--- a/cli/tests/integration/lsp_tests.rs
+++ b/cli/tests/integration/lsp_tests.rs
@@ -1401,7 +1401,9 @@ fn lsp_hover_change_mbc() {
               },
               "end": {
                 "line": 1,
-                "character": 13
+                // the LSP uses utf16 encoded characters indexes, so
+                // after the deno emoiji is character index 15
+                "character": 15
               }
             },
             "text": ""
@@ -1425,7 +1427,7 @@ fn lsp_hover_change_mbc() {
         },
         "position": {
           "line": 2,
-          "character": 14
+          "character": 15
         }
       }),
     )
@@ -1444,11 +1446,11 @@ fn lsp_hover_change_mbc() {
       "range": {
         "start": {
           "line": 2,
-          "character": 13,
+          "character": 15,
         },
         "end": {
           "line": 2,
-          "character": 14,
+          "character": 16,
         },
       }
     }))
@@ -4284,7 +4286,7 @@ fn lsp_performance() {
     .unwrap();
   assert!(maybe_err.is_none());
   if let Some(res) = maybe_res {
-    assert_eq!(res.averages.len(), 14);
+    assert_eq!(res.averages.len(), 13);
   } else {
     panic!("unexpected result");
   }
diff --git a/cli/tsc.rs b/cli/tsc.rs
index aba289d8c..d629fb80b 100644
--- a/cli/tsc.rs
+++ b/cli/tsc.rs
@@ -422,7 +422,7 @@ struct LoadArgs {
   specifier: String,
 }
 
-fn as_ts_script_kind(media_type: &MediaType) -> i32 {
+pub fn as_ts_script_kind(media_type: &MediaType) -> i32 {
   match media_type {
     MediaType::JavaScript => 1,
     MediaType::Jsx => 2,
@@ -492,7 +492,7 @@ fn op_load(state: &mut OpState, args: Value) -> Result<Value, AnyError> {
   };
 
   Ok(
-    json!({ "data": data, "hash": hash, "scriptKind": as_ts_script_kind(&media_type) }),
+    json!({ "data": data, "version": hash, "scriptKind": as_ts_script_kind(&media_type) }),
   )
 }
 
@@ -1002,7 +1002,7 @@ mod tests {
       actual,
       json!({
         "data": "console.log(\"hello deno\");\n",
-        "hash": "149c777056afcc973d5fcbe11421b6d5ddc57b81786765302030d7fc893bf729",
+        "version": "149c777056afcc973d5fcbe11421b6d5ddc57b81786765302030d7fc893bf729",
         "scriptKind": 3,
       })
     );
@@ -1012,7 +1012,7 @@ mod tests {
   #[serde(rename_all = "camelCase")]
   struct LoadResponse {
     data: String,
-    hash: Option<String>,
+    version: Option<String>,
     script_kind: i64,
   }
 
@@ -1033,7 +1033,7 @@ mod tests {
       serde_json::from_value(value).expect("failed to deserialize");
     let expected = get_asset("lib.dom.d.ts").unwrap();
     assert_eq!(actual.data, expected);
-    assert!(actual.hash.is_some());
+    assert!(actual.version.is_some());
     assert_eq!(actual.script_kind, 3);
   }
 
@@ -1052,7 +1052,7 @@ mod tests {
       actual,
       json!({
         "data": "some content",
-        "hash": null,
+        "version": null,
         "scriptKind": 0,
       })
     );
@@ -1070,7 +1070,7 @@ mod tests {
       actual,
       json!({
         "data": null,
-        "hash": null,
+        "version": null,
         "scriptKind": 0,
       })
     )
diff --git a/cli/tsc/99_main_compiler.js b/cli/tsc/99_main_compiler.js
index 68f4f37f6..6d47b6ac7 100644
--- a/cli/tsc/99_main_compiler.js
+++ b/cli/tsc/99_main_compiler.js
@@ -72,6 +72,8 @@ delete Object.prototype.__proto__;
     }
   }
 
+  // In the case of the LSP, this is initialized with the assets
+  // when snapshotting and never added to or removed after that.
   /** @type {Map<string, ts.SourceFile>} */
   const sourceFileCache = new Map();
 
@@ -186,62 +188,6 @@ delete Object.prototype.__proto__;
     target: ts.ScriptTarget.ESNext,
   };
 
-  class ScriptSnapshot {
-    /** @type {string} */
-    specifier;
-    /** @type {string} */
-    version;
-    /**
-     * @param {string} specifier
-     * @param {string} version
-     */
-    constructor(specifier, version) {
-      this.specifier = specifier;
-      this.version = version;
-    }
-    /**
-     * @param {number} start
-     * @param {number} end
-     * @returns {string}
-     */
-    getText(start, end) {
-      const { specifier, version } = this;
-      debug(
-        `snapshot.getText(${start}, ${end}) specifier: ${specifier} version: ${version}`,
-      );
-      return core.opSync("op_get_text", { specifier, version, start, end });
-    }
-    /**
-     * @returns {number}
-     */
-    getLength() {
-      const { specifier, version } = this;
-      debug(`snapshot.getLength() specifier: ${specifier} version: ${version}`);
-      return core.opSync("op_get_length", { specifier, version });
-    }
-    /**
-     * @param {ScriptSnapshot} oldSnapshot
-     * @returns {ts.TextChangeRange | undefined}
-     */
-    getChangeRange(oldSnapshot) {
-      const { specifier, version } = this;
-      const { version: oldVersion } = oldSnapshot;
-      const oldLength = oldSnapshot.getLength();
-      debug(
-        `snapshot.getLength() specifier: ${specifier} oldVersion: ${oldVersion} version: ${version}`,
-      );
-      return core.opSync(
-        "op_get_change_range",
-        { specifier, oldLength, oldVersion, version },
-      );
-    }
-    dispose() {
-      const { specifier, version } = this;
-      debug(`snapshot.dispose() specifier: ${specifier} version: ${version}`);
-      core.opSync("op_dispose", { specifier, version });
-    }
-  }
-
   /** Error thrown on cancellation. */
   class OperationCanceledError extends Error {
   }
@@ -310,16 +256,17 @@ delete Object.prototype.__proto__;
           ts.ScriptTarget[languageVersion]
         })`,
       );
+
+      // Needs the original specifier
+      specifier = normalizedToOriginalMap.get(specifier) ?? specifier;
+
       let sourceFile = sourceFileCache.get(specifier);
       if (sourceFile) {
         return sourceFile;
       }
 
-      // Needs the original specifier
-      specifier = normalizedToOriginalMap.get(specifier) ?? specifier;
-
-      /** @type {{ data: string; hash?: string; scriptKind: ts.ScriptKind }} */
-      const { data, hash, scriptKind } = core.opSync(
+      /** @type {{ data: string; scriptKind: ts.ScriptKind }} */
+      const { data, scriptKind, version } = core.opSync(
         "op_load",
         { specifier },
       );
@@ -335,8 +282,9 @@ delete Object.prototype.__proto__;
         scriptKind,
       );
       sourceFile.moduleName = specifier;
-      sourceFile.version = hash;
+      sourceFile.version = version;
       sourceFileCache.set(specifier, sourceFile);
+      scriptVersionCache.set(specifier, version);
       return sourceFile;
     },
     getDefaultLibFileName() {
@@ -445,11 +393,17 @@ delete Object.prototype.__proto__;
           },
         };
       }
-      const version = host.getScriptVersion(specifier);
-      if (version != null) {
-        return new ScriptSnapshot(specifier, version);
+
+      const fileInfo = core.opSync(
+        "op_load",
+        { specifier },
+      );
+      if (fileInfo) {
+        scriptVersionCache.set(specifier, fileInfo.version);
+        return ts.ScriptSnapshot.fromString(fileInfo.data);
+      } else {
+        return undefined;
       }
-      return undefined;
     },
   };