Refactor server lifecycle

editors/code/src/ctx.ts

@@ -1,19 +1,38 @@
 import * as vscode from 'vscode';
 import * as lc from 'vscode-languageclient';
-import { Server } from './server';
 import { Config } from './config';
+import { createClient } from './client'
 
 export class Ctx {
     readonly config: Config;
+    // Because we have "reload server" action, various listeners **will** face a
+    // situation where the client is not ready yet, and should be prepared to
+    // deal with it.
+    //
+    // Ideally, this should be replaced with async getter though.
+    client: lc.LanguageClient | null = null
     private extCtx: vscode.ExtensionContext;
+    private onDidRestartHooks: Array<(client: lc.LanguageClient) => void> = [];
 
     constructor(extCtx: vscode.ExtensionContext) {
         this.config = new Config(extCtx)
         this.extCtx = extCtx;
     }
 
-    get client(): lc.LanguageClient {
-        return Server.client;
+    async restartServer() {
+        let old = this.client;
+        if (old) {
+            await old.stop()
+        }
+        this.client = null;
+        const client = createClient(this.config);
+        this.pushCleanup(client.start());
+        await client.onReady();
+
+        this.client = client
+        for (const hook of this.onDidRestartHooks) {
+            hook(client)
+        }
     }
 
     get activeRustEditor(): vscode.TextEditor | undefined {
@@ -60,35 +79,34 @@ export class Ctx {
         this.extCtx.subscriptions.push(d);
     }
 
-    async sendRequestWithRetry<R>(
-        method: string,
-        param: any,
-        token?: vscode.CancellationToken,
-    ): Promise<R> {
-        await this.client.onReady();
-        for (const delay of [2, 4, 6, 8, 10, null]) {
-            try {
-                return await (token ? this.client.sendRequest(method, param, token) : this.client.sendRequest(method, param));
-            } catch (e) {
-                if (
-                    e.code === lc.ErrorCodes.ContentModified &&
-                    delay !== null
-                ) {
-                    await sleep(10 * (1 << delay));
-                    continue;
-                }
-                throw e;
-            }
-        }
-        throw 'unreachable';
-    }
-
-    onNotification(method: string, handler: lc.GenericNotificationHandler) {
-        this.client.onReady()
-            .then(() => this.client.onNotification(method, handler))
+    onDidRestart(hook: (client: lc.LanguageClient) => void) {
+        this.onDidRestartHooks.push(hook)
     }
 }
 
 export type Cmd = (...args: any[]) => any;
 
+export async function sendRequestWithRetry<R>(
+    client: lc.LanguageClient,
+    method: string,
+    param: any,
+    token?: vscode.CancellationToken,
+): Promise<R> {
+    for (const delay of [2, 4, 6, 8, 10, null]) {
+        try {
+            return await (token ? client.sendRequest(method, param, token) : client.sendRequest(method, param));
+        } catch (e) {
+            if (
+                e.code === lc.ErrorCodes.ContentModified &&
+                delay !== null
+            ) {
+                await sleep(10 * (1 << delay));
+                continue;
+            }
+            throw e;
+        }
+    }
+    throw 'unreachable';
+}
+
 const sleep = (ms: number) => new Promise(resolve => setTimeout(resolve, ms));