fix: mounting home fs multiple times will throw error (#175)

Author: bytemain

packages/common/src/index.ts

@@ -1,2 +1,3 @@
+export * from './mutex';
 export * from './request';
 export * from './types';

packages/common/src/mutex.ts

@@ -0,0 +1,22 @@
+export class Mutex {
+  private mutex = Promise.resolve();
+
+  lock(): PromiseLike<() => void> {
+    let begin: (unlock: () => void) => void = () => {};
+
+    this.mutex = this.mutex.then(() => new Promise(begin));
+
+    return new Promise((res) => {
+      begin = res;
+    });
+  }
+
+  async dispatch<T>(fn: () => PromiseLike<T>): Promise<T> {
+    const unlock = await this.lock();
+    try {
+      return await Promise.resolve(fn());
+    } finally {
+      unlock();
+    }
+  }
+}

packages/sumi-core/src/server/core/filesystem.ts

@@ -1,7 +1,8 @@
-import { Deferred, getDebugLogger } from '@opensumi/ide-core-common';
+import { Mutex } from '@codeblitzjs/ide-common';
+import { Deferred, Disposable, getDebugLogger } from '@opensumi/ide-core-common';
 import { HOME_IDB_NAME, HOME_ROOT } from '../../common';
 import { RootFS } from '../../common/types';
-import { BrowserFS, FileSystem } from '../node';
+import { BrowserFS, FileSystem, isPathMounted } from '../node';
 
 const { createFileSystem, FileSystem, initialize } = BrowserFS;
 
@@ -11,18 +12,18 @@ export const filesystemDeferred = new Deferred<void>();
 export const isFilesystemReady = () => filesystemDeferred.promise;
 
 let mountfs: RootFS | null = null;
-let mountfsDeferred: Deferred<RootFS> | null = null;
+let mountRootFsMutex = new Mutex();
 
 export const initializeRootFileSystem = async () => {
-  if (mountfsDeferred) return mountfsDeferred.promise;
+  return mountRootFsMutex.dispatch(async () => {
+    if (mountfs) return mountfs;
 
-  mountfsDeferred = new Deferred<RootFS>();
-  mountfs = (await createFileSystem(FileSystem.MountableFileSystem, {})) as RootFS;
-  mountfsDeferred.resolve(mountfs);
+    mountfs = (await createFileSystem(FileSystem.MountableFileSystem, {})) as RootFS;
 
-  initialize(mountfs);
-  filesystemDeferred.resolve();
-  return mountfs;
+    initialize(mountfs);
+    filesystemDeferred.resolve();
+    return mountfs;
+  });
 };
 
 export const unmountRootFS = () => {
@@ -32,34 +33,42 @@ export const unmountRootFS = () => {
   }
 };
 
+const initHomeFsMutex = new Mutex();
+
 export const initializeHomeFileSystem = async (rootFS: RootFS, scenario?: string | null) => {
-  try {
-    let homefs: FileSystem | null = null;
-    // scenario 为 null 时 或者 browser 隐身模式时无法使用 indexedDB 时，回退到 memory
-    // TODO: 寻找更好的解决方案
-    if (scenario !== null && FileSystem.IndexedDB.isAvailable()) {
-      try {
-        // 通过 scenario 隔离 indexedDB
-        homefs = await createFileSystem(FileSystem.IndexedDB, {
-          storeName: `${HOME_IDB_NAME}${scenario ? `/${scenario}` : ''}`,
-        });
-      } catch (err) {
-        // @ts-ignore
-        getDebugLogger().error(`初始化 indexedDB 文件系统失败 ${err?.message || ''}`);
-        homefs = null;
-      }
+  return await initHomeFsMutex.dispatch(async () => {
+    // 如果用户使用了多个 codeblitz 实例，第一个挂载的先生效
+    if (isPathMounted(rootFS, HOME_ROOT)) {
+      return Disposable.NULL;
     }
-    if (!homefs) {
-      homefs = await createFileSystem(FileSystem.InMemory, {});
+
+    try {
+      let homefs: FileSystem | null = null;
+      // scenario 为 null 时 或者 browser 隐身模式时无法使用 indexedDB 时，回退到 memory
+      // TODO: 寻找更好的解决方案
+      if (scenario !== null && FileSystem.IndexedDB.isAvailable()) {
+        try {
+          // 通过 scenario 隔离 indexedDB
+          homefs = await createFileSystem(FileSystem.IndexedDB, {
+            storeName: `${HOME_IDB_NAME}${scenario ? `/${scenario}` : ''}`,
+          });
+        } catch (err) {
+          getDebugLogger().error(`初始化 indexedDB 文件系统失败 ${(err as Error)?.message || ''}`);
+          homefs = null;
+        }
+      }
+      if (!homefs) {
+        homefs = await createFileSystem(FileSystem.InMemory, {});
+      }
+      rootFS.mount(HOME_ROOT, homefs);
+    } catch (err) {
+      getDebugLogger().error(`初始化 home 目录失败 ${(err as Error)?.message || ''}`);
     }
-    rootFS.mount(HOME_ROOT, homefs);
-  } catch (err) {
-    // @ts-ignore
-    getDebugLogger().error(`初始化 home 目录失败 ${err?.message || ''}`);
-  }
-  return {
-    dispose() {
-      rootFS.umount(HOME_ROOT);
-    },
-  };
+
+    return {
+      dispose() {
+        rootFS.umount(HOME_ROOT);
+      },
+    };
+  });
 };