Refactoring

Author: AndreasArvidsson

src/Trees.ts

@@ -0,0 +1,64 @@
+import type { Position, TextDocumentChangeEvent } from "vscode";
+import { Edit, type Parser, type Point, type Tree } from "web-tree-sitter";
+
+export class Trees {
+  private trees: Map<string, Tree> = new Map();
+
+  get(uri: string): Tree | undefined {
+    return this.trees.get(uri);
+  }
+
+  set(uri: string, tree: Tree): void {
+    this.trees.set(uri, tree);
+  }
+
+  delete(uri: string): void {
+    this.trees.delete(uri);
+  }
+
+  updateTree(parser: Parser, edit: TextDocumentChangeEvent) {
+    if (edit.contentChanges.length === 0) {
+      return;
+    }
+
+    const uriString = edit.document.uri.toString();
+    const old = this.trees.get(uriString);
+
+    if (old == null) {
+      throw new Error(`No existing tree for ${uriString}`);
+    }
+
+    for (const e of edit.contentChanges) {
+      const startIndex = e.rangeOffset;
+      const oldEndIndex = e.rangeOffset + e.rangeLength;
+      const newEndIndex = e.rangeOffset + e.text.length;
+      const startPos = edit.document.positionAt(startIndex);
+      const oldEndPos = edit.document.positionAt(oldEndIndex);
+      const newEndPos = edit.document.positionAt(newEndIndex);
+      const startPosition = asPoint(startPos);
+      const oldEndPosition = asPoint(oldEndPos);
+      const newEndPosition = asPoint(newEndPos);
+      const delta = new Edit({
+        startIndex,
+        oldEndIndex,
+        newEndIndex,
+        startPosition,
+        oldEndPosition,
+        newEndPosition,
+      });
+      old.edit(delta);
+    }
+
+    const tree = parser.parse(edit.document.getText(), old);
+
+    if (tree == null) {
+      throw Error(`Failed to parse ${uriString}`);
+    }
+
+    this.trees.set(uriString, tree);
+  }
+}
+
+function asPoint(pos: Position): Point {
+  return { row: pos.line, column: pos.character };
+}

src/errors.ts

@@ -7,10 +7,10 @@ export class UnsupportedLanguageError extends Error {
   }
 }
 
-export class LanguageStillLoadingError extends Error {
+export class LanguageFailedToLoad extends Error {
   constructor(language: string) {
-    super(`Language '${language}' is still loading; please wait and try again`);
-    this.name = "LanguageStillLoadingError";
+    super(`Language '${language}' failed to load`);
+    this.name = "LanguageFailedToLoad";
   }
 }