原文地址:https://github.com/fanfeilong/cefutil/blob/master/doc/CEF_Close.md
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我来说windows下CEF3.2171的关闭流程,里面会引用一部分官方库的文档和个人的伪代码,为了辅助理解—— 以下是截取自cef_life_span_handler.h的头文件文档,所以一部分文档他还是写在头文件里的,根据他的流程,能很快的去梳理相关逻辑
// The CefLifeSpanHandler::OnBeforeClose() method will be called immediately // before the browser object is destroyed. The application should only exit // after OnBeforeClose() has been called for all existing browsers. // // If the browser represents a modal window and a custom modal loop // implementation was provided in CefLifeSpanHandler::RunModal() this callback // should be used to restore the opener window to a usable state. // // By way of example consider what should happen during window close when the // browser is parented to an application-provided top-level OS window. // 1. User clicks the window close button which sends an OS close // notification (e.g. WM_CLOSE on Windows, performClose: on OS-X and // "delete_event" on Linux). // 2. Application's top-level window receives the close notification and: // A. Calls CefBrowserHost::CloseBrowser(false). // B. Cancels the window close. // 3. JavaScript 'onbeforeunload' handler executes and shows the close // confirmation dialog (which can be overridden via // CefJSDialogHandler::OnBeforeUnloadDialog()). // 4. User approves the close. // 5. JavaScript 'onunload' handler executes. // 6. Application's DoClose() handler is called. Application will: // A. Set a flag to indicate that the next close attempt will be allowed. // B. Return false. // 7. CEF sends an OS close notification. // 8. Application's top-level window receives the OS close notification and // allows the window to close based on the flag from #6B. // 9. Browser OS window is destroyed. // 10. Application's CefLifeSpanHandler::OnBeforeClose() handler is called and // the browser object is destroyed. // 11. Application exits by calling CefQuitMessageLoop() if no other browsers // exist.
pre1. 如果你要管理CefBrowser的生命周期,意味者你必须实现相关 CefLifeSpanHandler接口,在OnAfterCreated里管理和获取CefBrowser的每一个browser,在DoClose和OnBeforeClose里管理关闭 pre2. 这里要注意整个流程对应开发者来说不是线性代码,都是基于消息、事件投递、接口切面的一种编程习惯,大家要对异步接口的开发有心理准备,你实现的一个接口都是等待框架或者别人调用。
- 用户发起了一个系统级别的关闭操作,比如CLOSE,window下会被WM_CLOSE和相关封装触发
- 系统的顶层窗口消息处理会获取到CLOSE消息 A. 调用 CefBrowserHost::CloseBrowser(false), 通知HOST开始关闭流程,参数force_close=false,我们不需要交互式关闭。 B. 取消系统级关闭,比如以下代码我"return 0; "拒接了系统窗口的关闭流程,进入了个人和CEF的流程
case WM_CLOSE: if (client && !client->IsClosing()) { CefRefPtr<CefBrowser> browser = client->GetBrowser(); if (browser.get()) { // Notify the browser window that we would like to close it. This // will result in a call to ClientHandler::DoClose() if the // JavaScript 'onbeforeunload' event handler allows it. browser->GetHost()->CloseBrowser(false); // Cancel the close. return 0; } } // Allow the close. break;
这是单browser关闭
browser->GetHost()->CloseBrowser(false);
同样可以替换成多browser关闭
void ClientHandler::CloseAllBrowsers(bool force_close) { if (!CefCurrentlyOn(TID_UI)) { // Execute on the UI thread. CefPostTask(TID_UI, base::Bind(&ClientHandler::CloseAllBrowsers, this, force_close)); return; } if (!popup_browsers_.empty()) { // Request that any popup browsers close. BrowserList::const_iterator it = popup_browsers_.begin(); for (; it != popup_browsers_.end(); ++it) (*it)->GetHost()->CloseBrowser(force_close); } if (browser_.get()) { // Request that the main browser close. browser_->GetHost()->CloseBrowser(force_close); } }
intermittent. 最终会触发一个或多个CloseBrowser => CefBrowserHostImpl::CloseBrowser => CefBrowserHostImpl::CloseContents
void CefBrowserHostImpl::CloseBrowser(bool force_close) { if (CEF_CURRENTLY_ON_UIT()) { // Exit early if a close attempt is already pending and this method is // called again from somewhere other than WindowDestroyed(). if (destruction_state_ >= DESTRUCTION_STATE_PENDING && (IsWindowless() || !window_destroyed_)) { if (force_close && destruction_state_ == DESTRUCTION_STATE_PENDING) { // Upgrade the destruction state. destruction_state_ = DESTRUCTION_STATE_ACCEPTED; } return; } if (destruction_state_ < DESTRUCTION_STATE_ACCEPTED) { destruction_state_ = (force_close ? DESTRUCTION_STATE_ACCEPTED : DESTRUCTION_STATE_PENDING); } content::WebContents* contents = web_contents(); if (contents && contents->NeedToFireBeforeUnload()) { // Will result in a call to BeforeUnloadFired() and, if the close isn't // canceled, CloseContents(). contents->DispatchBeforeUnload(false); } else { CloseContents(contents); } } else { CEF_POST_TASK(CEF_UIT, base::Bind(&CefBrowserHostImpl::CloseBrowser, this, force_close)); } }
我们跳过其他细节( 我也没关注:) ),和相关CEF_POST_TASK把函数投递到UI线程上去处理的线程类型,最后会进入 CloseContents
void CefBrowserHostImpl::CloseContents(content::WebContents* source) { if (destruction_state_ == DESTRUCTION_STATE_COMPLETED) return; bool close_browser = true; // If this method is called in response to something other than // WindowDestroyed() ask the user if the browser should close. if (client_.get() && (IsWindowless() || !window_destroyed_)) { CefRefPtr<CefLifeSpanHandler> handler = client_->GetLifeSpanHandler(); if (handler.get()) { close_browser = !handler->DoClose(this); // CefLifeSpanHandler::DoClose } } if (close_browser) { if (destruction_state_ != DESTRUCTION_STATE_ACCEPTED) destruction_state_ = DESTRUCTION_STATE_ACCEPTED; if (!IsWindowless() && !window_destroyed_) { // A window exists so try to close it using the platform method. Will // result in a call to WindowDestroyed() if/when the window is destroyed // via the platform window destruction mechanism. PlatformCloseWindow(); } else { // Keep a reference to the browser while it's in the process of being // destroyed. CefRefPtr<CefBrowserHostImpl> browser(this); // No window exists. Destroy the browser immediately. DestroyBrowser(); // CefLifeSpanHandler::OnBeforeClose if (!IsWindowless()) { // Release the reference added in PlatformCreateWindow(). Release(); } } } else if (destruction_state_ != DESTRUCTION_STATE_NONE) { destruction_state_ = DESTRUCTION_STATE_NONE; } }
在CloseContents里发现了我们的DoClose接口,其实这个函数里还有我们要处理的OnBeforeClose接口,DestroyBrowser包含了他
void CefBrowserHostImpl::DestroyBrowser() { CEF_REQUIRE_UIT(); destruction_state_ = DESTRUCTION_STATE_COMPLETED; if (client_.get()) { CefRefPtr<CefLifeSpanHandler> handler = client_->GetLifeSpanHandler(); if (handler.get()) { // Notify the handler that the window is about to be closed. handler->OnBeforeClose(this); //`CefLifeSpanHandler::OnBeforeClose } } // 省略 }
到这里我们要有这样的调用栈初步概念(之后会修改..)
=> 表示同步调用 ->异步调用 [os]window close => [个人]browser(s) close => [cef]CefBrowserHostImpl::CloseBrowser => [cef]CefBrowserHostImpl::CloseContents => [实现cef接口]CefLifeSpanHandler::DoClose => [cef]CefLifeSpanHandler::DestroyBrowser => [实现cef接口]CefLifeSpanHandler::OnBeforeClose => [os]阻止window close
3-5. js和交互级的操作,略,其中有一点js onunload让你有机会在js层面去通知关闭,比如通知后台的native 线程去做自我清理动作,特别是cefQuery持久化以后的和JS交互的native线程 6.DoClose接口被调用 A. 允许设置一些状态表示browser正在关闭 B. "return false;" 我们不需要紧急关闭(好像是预留接口,或者其他平台用) 7.cef 发送一个系统级别的关闭动作发现之前的调用栈已经需要修改了,因为这里异步操作) CloseContents => PlatformCloseWindow => CefBrowserHostImpl::PlatformCloseWindow =>PostMessage WM_CLOSE
void CefBrowserHostImpl::PlatformCloseWindow() { if (window_info_.window != NULL) { HWND frameWnd = GetAncestor(window_info_.window, GA_ROOT); PostMessage(frameWnd, WM_CLOSE, 0, 0); } }
PS: host公共代码在这个文件browser_host_impl.cc里,平台特殊接口在browser_host_impl_xxx.cc里 PlatformCloseWindow在browser_host_impl_win.cc里
允许关闭"if (client && !client->IsClosing()) " 之前我代码里IsClosing已经允许(
case WM_CLOSE: if (client && !client->IsClosing()) { // 这次不会进入IF分支
8.系统窗口已销毁
LRESULT CALLBACK CefBrowserHostImpl::WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam) { // 略 case WM_DESTROY: if (browser) { // Clear the user data pointer. gfx::SetWindowUserData(hwnd, NULL); // Force the browser to be destroyed and release the reference added in // PlatformCreateWindow(). browser->WindowDestroyed(); } return 0; // 略 }
cef竟然在等系统群发销毁消息然后处理的代码,看到这里才发现CefBrowserHostImpl这个类是CefBrowser和系统整合的桥梁,不同平台对 CefBrowserHostImpl 的实现也不一样
9.框架发起销毁操作 10. 调用OnBeforeClose WM_DESTROY => CefBrowserHostImpl::WindowDestroyed => ClientHandler::OnBeforeClose
void ClientHandler::OnBeforeClose(CefRefPtr<CefBrowser> browser) { CEF_REQUIRE_UI_THREAD(); message_router_->OnBeforeClose(browser); if (GetBrowserId() == browser->GetIdentifier()) { { base::AutoLock lock_scope(lock_); // Free the browser pointer so that the browser can be destroyed browser_ = NULL; } if (osr_handler_.get()) { osr_handler_->OnBeforeClose(browser); osr_handler_ = NULL; } } else if (browser->IsPopup()) { // Remove from the browser popup list. BrowserList::iterator bit = popup_browsers_.begin(); for (; bit != popup_browsers_.end(); ++bit) { if ((*bit)->IsSame(browser)) { popup_browsers_.erase(bit); break; } } } if (--browser_count_ == 0) { // All browser windows have closed. // Remove and delete message router handlers. MessageHandlerSet::const_iterator it = message_handler_set_.begin(); for (; it != message_handler_set_.end(); ++it) { message_router_->RemoveHandler(*(it)); delete *(it); } message_handler_set_.clear(); message_router_ = NULL; // Quit the application message loop. //AppQuitMessageLoop(); XCefAppManage::Instance()->QuitMessageLoop(); } }
我判断到 "--browser_count_ == 0" , 开始发起真实关闭。
- 发起的真实关闭逻辑 个人在OnBeforeClose里销毁所有browser和相关操作cefquery组件销毁以后,发起了总的关闭流程(关闭是异步的)
void XCefAppManage::QuitMessageLoop() { if (GetCefSettings().multi_threaded_message_loop) { // Running in multi-threaded message loop mode. Need to execute // PostQuitMessage on the main application thread. if (NULL == message_wnd__) { message_wnd__ = ::FindWindow(XWinUtil::GetMessageWindowClassName(XWinUtil::GetParentProcessID()), NULL); } DCHECK(message_wnd__); PostMessage(message_wnd__, WM_COMMAND, ID_QUIT, 0); } else { CefQuitMessageLoop(); } }
如果CefRunMessageLoop创建的消息循环对应CefQuitMessageLoop去终结,其他方式的处理就千奇百怪了,我根据cefclient的例子用一个隐藏窗口来结束系统的消息循环
PostMessage(message_wnd__, WM_COMMAND, ID_QUIT, 0);
处理非常简单,调用了原生API PostQuitMessage退出循环
case ID_QUIT: PostQuitMessage(0); return 0;
PS: 如果需要把CEF混入其他框架的话,不同框架的处理都需要适配,切记。 12. CefShutDown() 销毁Cef资源,如果有资源没关闭,比如browser的计数不为0,debug下会check assert。 最后我再来修改一下之前的调用栈
=> 表示同步调用 ->异步调用 [os]on window close WM_CLOSE => [个人]browser(s) close => [cef]CefBrowserHostImpl::CloseBrowser => [cef]CefBrowserHostImpl::CloseContents => [实现cef接口]CefLifeSpanHandler::DoClose => [cef]CefBrowserHostImpl::PlatformCloseWindow => [os] post window close -> WM_CLOSE [os]阻止window close post被接收 [os] 第二次on window close WM_CLOSE => [个人] 允许 window close ->WM_DESTROY [os] 系统群发WM_DESTROY [cef] CefBrowserHostImpl::WndProc => [cef & os] 每个browser proc内的 WM_CLOSE 处理 [cef]CefLifeSpanHandler::DestroyBrowser => [实现cef接口]CefLifeSpanHandler::OnBeforeClose => 发起总关闭(个人使用XCefAppManage::QuitMessageLoop)-> 退出消息循环 CefShutDown
这就一些对CEF CLOSE的个人理解的心得
标签:cef,CefBrowserHostImpl,windows,流程,CEF3,window,handler,close,browser From: https://www.cnblogs.com/kn-zheng/p/17000368.html