VSCode源码分析 - 进程通信

目录

• 启动主进程
• 实例化服务
• 事件分发
• 进程通信
• 主要窗口
• 开发调试

进程通信

主进程

src/vs/code/electron-main/main.ts

main.ts在启动应用后就创建了一个主进程 main process，它可以通过electron中的一些模块直接与原生GUI交互。

server = await serve(environmentService.mainIPCHandle);
once(lifecycleService.onWillShutdown)(() => server.dispose());

渲染进程

仅启动主进程并不能给你的应用创建应用窗口。窗口是通过main文件里的主进程调用叫BrowserWindow的模块创建的。

主进程与渲染进程之间的通信

在electron中，主进程与渲染进程有很多通信的方法。比如ipcRenderer和ipcMain，还可以在渲染进程使用remote模块。

ipcMain & ipcRenderer

• 主进程：ipcMain
• 渲染进程：ipcRenderer

ipcMain模块和ipcRenderer是类EventEmitter的实例。

在主进程中使用ipcMain接收渲染线程发送过来的异步或同步消息，发送过来的消息将触发事件。

在渲染进程中使用ipcRenderer向主进程发送同步或异步消息，也可以接收到主进程的消息。

• 发送消息，事件名为 channel .
• 回应同步消息, 你可以设置 event.returnValue .
• 回应异步消息, 你可以使用 event.sender.send(...)

创建IPC服务 src/vs/base/parts/ipc/node/ipc.net.ts

这里返回一个promise对象，成功则createServer

export function serve(hook: any): Promise<Server> {
    return new Promise<Server>((c, e) => {
        const server = createServer();

        server.on('error', e);
        server.listen(hook, () => {
            server.removeListener('error', e);
            c(new Server(server));
        });
    });
}

创建信道

src/vs/code/electron-main/app.ts

• mainIpcServer

  • launchChannel

• electronIpcServer

  • updateChannel
  • issueChannel
  • workspacesChannel
  • windowsChannel
  • menubarChannel
  • urlChannel
  • storageChannel
  • logLevelChannel

private openFirstWindow(accessor: ServicesAccessor, electronIpcServer: ElectronIPCServer, sharedProcessClient: Promise<Client<string>>): ICodeWindow[] {

        // Register more Main IPC services
        const launchService = accessor.get(ILaunchService);
        const launchChannel = new LaunchChannel(launchService);
        this.mainIpcServer.registerChannel('launch', launchChannel);

        // Register more Electron IPC services
        const updateService = accessor.get(IUpdateService);
        const updateChannel = new UpdateChannel(updateService);
        electronIpcServer.registerChannel('update', updateChannel);

        const issueService = accessor.get(IIssueService);
        const issueChannel = new IssueChannel(issueService);
        electronIpcServer.registerChannel('issue', issueChannel);

        const workspacesService = accessor.get(IWorkspacesMainService);
        const workspacesChannel = new WorkspacesChannel(workspacesService);
        electronIpcServer.registerChannel('workspaces', workspacesChannel);

        const windowsService = accessor.get(IWindowsService);
        const windowsChannel = new WindowsChannel(windowsService);
        electronIpcServer.registerChannel('windows', windowsChannel);
        sharedProcessClient.then(client => client.registerChannel('windows', windowsChannel));

        const menubarService = accessor.get(IMenubarService);
        const menubarChannel = new MenubarChannel(menubarService);
        electronIpcServer.registerChannel('menubar', menubarChannel);

        const urlService = accessor.get(IURLService);
        const urlChannel = new URLServiceChannel(urlService);
        electronIpcServer.registerChannel('url', urlChannel);

        const storageMainService = accessor.get(IStorageMainService);
        const storageChannel = this._register(new GlobalStorageDatabaseChannel(this.logService, storageMainService));
        electronIpcServer.registerChannel('storage', storageChannel);

        // Log level management
        const logLevelChannel = new LogLevelSetterChannel(accessor.get(ILogService));
        electronIpcServer.registerChannel('loglevel', logLevelChannel);
        sharedProcessClient.then(client => client.registerChannel('loglevel', logLevelChannel));

        ...

        // default: read paths from cli
        return windowsMainService.open({
            context,
            cli: args,
            forceNewWindow: args['new-window'] || (!hasCliArgs && args['unity-launch']),
            diffMode: args.diff,
            noRecentEntry,
            waitMarkerFileURI,
            gotoLineMode: args.goto,
            initialStartup: true
        });
    }

每一个信道，内部实现两个方法 listen和call

例如：src/vs/platform/localizations/node/localizationsIpc.ts

构造函数绑定事件

export class LocalizationsChannel implements IServerChannel {

    onDidLanguagesChange: Event<void>;

    constructor(private service: ILocalizationsService) {
        this.onDidLanguagesChange = Event.buffer(service.onDidLanguagesChange, true);
    }

    listen(_: unknown, event: string): Event<any> {
        switch (event) {
            case 'onDidLanguagesChange': return this.onDidLanguagesChange;
        }

        throw new Error(`Event not found: ${event}`);
    }

    call(_: unknown, command: string, arg?: any): Promise<any> {
        switch (command) {
            case 'getLanguageIds': return this.service.getLanguageIds(arg);
        }

        throw new Error(`Call not found: ${command}`);
    }
}