TraceServer: Add an explicit foreign server check

If a foreign server is already running, the start command used to miss
that and keep going, upon a yet defined server.pid. Add an isUp check
now to prevent startup from proceeding, should a known foreign server be
already running.

Checking for server.exitCode or server.signalCode at this early startup
stage couldn't fix this, because both are prematurely set as 'none',
which means a running spawned server.

Contributes to fixing #8.

Signed-off-by: Marco Miller <marco.miller@ericsson.com>

Author: marco-miller

src/trace-server.ts

@@ -67,10 +67,11 @@ export class TraceServer {
         this.server = undefined;
     }
 
-    startIfStopped(context: vscode.ExtensionContext | undefined) {
+    async startIfStopped(context: vscode.ExtensionContext | undefined) {
         const pid = context?.workspaceState.get(key);
         const stopped = !pid || pid === none;
-        if (stopped) {
+        const foreigner = await this.isUp();
+        if (stopped && !foreigner) {
             this.start(context);
         }
     }