From 44c216cf5d27fd3a18d2f629a4518817facd07f7 Mon Sep 17 00:00:00 2001
From: 0dinD <zerodind@gmail.com>
Date: Tue, 22 Sep 2020 12:48:14 +0200
Subject: [PATCH] Fix semantic tokens offset due to document updates

Signed-off-by: 0dinD <zerodind@gmail.com>
---
 src/semanticTokenProvider.ts | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/src/semanticTokenProvider.ts b/src/semanticTokenProvider.ts
index fbc43f5a92..fbc021e825 100644
--- a/src/semanticTokenProvider.ts
+++ b/src/semanticTokenProvider.ts
@@ -26,7 +26,14 @@ export function registerSemanticTokensProvider(context: vscode.ExtensionContext)
 
 class SemanticTokensProvider implements vscode.DocumentSemanticTokensProvider {
     async provideDocumentSemanticTokens(document: vscode.TextDocument, token: vscode.CancellationToken): Promise<vscode.SemanticTokens> {
+        const versionBeforeRequest: number = document.version;
         const response = <any> await vscode.commands.executeCommand(Commands.EXECUTE_WORKSPACE_COMMAND, Commands.PROVIDE_SEMANTIC_TOKENS, document.uri.toString());
+        const versionAfterRequest: number = document.version;
+
+        if (versionBeforeRequest !== versionAfterRequest) {
+            await waitForDocumentChangesToEnd(document);
+            throw new Error("busy");
+        }
         if (token.isCancellationRequested) {
             return undefined;
         }
@@ -37,6 +44,19 @@ class SemanticTokensProvider implements vscode.DocumentSemanticTokensProvider {
     }
 }
 
+function waitForDocumentChangesToEnd(document: vscode.TextDocument): Promise<void> {
+    let version = document.version;
+    return new Promise((resolve) => {
+        const iv = setInterval(() => {
+            if (document.version === version) {
+                clearInterval(iv);
+                resolve();
+            }
+            version = document.version;
+        }, 400);
+    });
+}
+
 const semanticTokensProvider = new SemanticTokensProvider();
 
 async function getSemanticTokensLegend(): Promise<vscode.SemanticTokensLegend | undefined> {