WebKit事件派发

最新推荐文章于 2024-06-07 18:03:29 发布

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最新推荐文章于 2024-06-07 18:03:29 发布

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本文解析了WebKit在32位平台上如何处理设备事件、网络事件及定时器事件，并探讨了内部事件处理方式，提出统一事件处理架构的想法。

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http://blog.youkuaiyun.com/shunzi__1984/article/details/6192998

一般在一个网络应用系统中，都会一下几类事件：网络事件， timer事件，以及设备事件，设备事件主要指鼠标，按键，以及paint等消息事件

webkit也不例外,小弟分析了一下32平台的实现，也无特殊之处

1. 设备事件

设备事件仍然是通过win32平台的消息循环来派发，消息处理函数如下：

[cpp] view plain copy

LRESULT CALLBACK WebView::WebViewWndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
LRESULT lResult = 0;
LONG_PTR longPtr = GetWindowLongPtr(hWnd, 0);
WebView* webView = reinterpret_cast<WebView*>(longPtr);
WebFrame* mainFrameImpl = webView ? webView->topLevelFrame() : 0;
if (!mainFrameImpl || webView->isBeingDestroyed())
return DefWindowProc(hWnd, message, wParam, lParam);
// hold a ref, since the WebView could go away in an event handler.
COMPtr<WebView> protector(webView);
ASSERT(webView);
// Windows Media Player has a modal message loop that will deliver messages
// to us at inappropriate times and we will crash if we handle them when
// they are delivered. We repost paint messages so that we eventually get
// a chance to paint once the modal loop has exited, but other messages
// aren't safe to repost, so we just drop them.
if (PluginView::isCallingPlugin()) {
if (message == WM_PAINT)
PostMessage(hWnd, message, wParam, lParam);
return 0;
}
bool handled = true;
switch (message) {
case WM_PAINT: {
webView->paint(0, 0);
break;
}
case WM_PRINTCLIENT:
webView->paint((HDC)wParam, lParam);
break;
case WM_DESTROY:
webView->setIsBeingDestroyed();
webView->close();
break;
case WM_GESTURENOTIFY:
handled = webView->gestureNotify(wParam, lParam);
break;
case WM_GESTURE:
handled = webView->gesture(wParam, lParam);
break;
case WM_MOUSEMOVE:
case WM_LBUTTONDOWN:
case WM_MBUTTONDOWN:
case WM_RBUTTONDOWN:
case WM_LBUTTONDBLCLK:
case WM_MBUTTONDBLCLK:
case WM_RBUTTONDBLCLK:
case WM_LBUTTONUP:
case WM_MBUTTONUP:
case WM_RBUTTONUP:
case WM_MOUSELEAVE:
case WM_CANCELMODE:
if (Frame* coreFrame = core(mainFrameImpl))
if (coreFrame->view()->didFirstLayout())
handled = webView->handleMouseEvent(message, wParam, lParam);
break;
case WM_MOUSEWHEEL:
case WM_VISTA_MOUSEHWHEEL:
if (Frame* coreFrame = core(mainFrameImpl))
if (coreFrame->view()->didFirstLayout())
handled = webView->mouseWheel(wParam, lParam, message == WM_VISTA_MOUSEHWHEEL);
break;
case WM_SYSKEYDOWN:
handled = webView->keyDown(wParam, lParam, true);
break;
case WM_KEYDOWN:
handled = webView->keyDown(wParam, lParam);
break;
case WM_SYSKEYUP:
handled = webView->keyUp(wParam, lParam, true);
break;
case WM_KEYUP:
handled = webView->keyUp(wParam, lParam);
break;
case WM_SYSCHAR:
handled = webView->keyPress(wParam, lParam, true);
break;
case WM_CHAR:
handled = webView->keyPress(wParam, lParam);
break;
// FIXME: We need to check WM_UNICHAR to support supplementary characters (that don't fit in 16 bits).
case WM_SIZE:
if (lParam != 0)
webView->sizeChanged(IntSize(LOWORD(lParam), HIWORD(lParam)));
break;
case WM_SHOWWINDOW:
lResult = DefWindowProc(hWnd, message, wParam, lParam);
if (wParam == 0) {
// The window is being hidden (e.g., because we switched tabs).
// Null out our backing store.
webView->deleteBackingStore();
}
#if USE(ACCELERATED_COMPOSITING)
else if (webView->isAcceleratedCompositing())
webView->layerRendererBecameVisible();
#endif
break;
case WM_SETFOCUS: {
COMPtr<IWebUIDelegate> uiDelegate;
COMPtr<IWebUIDelegatePrivate> uiDelegatePrivate;
if (SUCCEEDED(webView->uiDelegate(&uiDelegate)) && uiDelegate
&& SUCCEEDED(uiDelegate->QueryInterface(IID_IWebUIDelegatePrivate, (void**) &uiDelegatePrivate)) && uiDelegatePrivate)
uiDelegatePrivate->webViewReceivedFocus(webView);
FocusController* focusController = webView->page()->focusController();
if (Frame* frame = focusController->focusedFrame()) {
// Send focus events unless the previously focused window is a
// child of ours (for example a plugin).
if (!IsChild(hWnd, reinterpret_cast<HWND>(wParam)))
focusController->setFocused(true);
} else
focusController->setFocused(true);
break;
}
case WM_KILLFOCUS: {
COMPtr<IWebUIDelegate> uiDelegate;
COMPtr<IWebUIDelegatePrivate> uiDelegatePrivate;
HWND newFocusWnd = reinterpret_cast<HWND>(wParam);
if (SUCCEEDED(webView->uiDelegate(&uiDelegate)) && uiDelegate
&& SUCCEEDED(uiDelegate->QueryInterface(IID_IWebUIDelegatePrivate, (void**) &uiDelegatePrivate)) && uiDelegatePrivate)
uiDelegatePrivate->webViewLostFocus(webView, (OLE_HANDLE)(ULONG64)newFocusWnd);
FocusController* focusController = webView->page()->focusController();
Frame* frame = focusController->focusedOrMainFrame();
webView->resetIME(frame);
// Send blur events unless we're losing focus to a child of ours.
if (!IsChild(hWnd, newFocusWnd))
focusController->setFocused(false);
// If we are pan-scrolling when we lose focus, stop the pan scrolling.
frame->eventHandler()->stopAutoscrollTimer();
break;
}
case WM_WINDOWPOSCHANGED:
if (reinterpret_cast<WINDOWPOS*>(lParam)->flags & SWP_SHOWWINDOW)
webView->updateActiveStateSoon();
handled = false;
break;
case WM_CUT:
webView->cut(0);
break;
case WM_COPY:
webView->copy(0);
break;
case WM_PASTE:
webView->paste(0);
break;
case WM_CLEAR:
webView->delete_(0);
break;
case WM_COMMAND:
if (HIWORD(wParam))
handled = webView->execCommand(wParam, lParam);
else // If the high word of wParam is 0, the message is from a menu
webView->performContextMenuAction(wParam, lParam, false);
break;
case WM_MENUCOMMAND:
webView->performContextMenuAction(wParam, lParam, true);
break;
case WM_CONTEXTMENU:
handled = webView->handleContextMenuEvent(wParam, lParam);
break;
case WM_INITMENUPOPUP:
handled = webView->onInitMenuPopup(wParam, lParam);
break;
case WM_MEASUREITEM:
handled = webView->onMeasureItem(wParam, lParam);
break;
case WM_DRAWITEM:
handled = webView->onDrawItem(wParam, lParam);
break;
case WM_UNINITMENUPOPUP:
handled = webView->onUninitMenuPopup(wParam, lParam);
break;
case WM_XP_THEMECHANGED:
if (Frame* coreFrame = core(mainFrameImpl)) {
webView->deleteBackingStore();
coreFrame->page()->theme()->themeChanged();
ScrollbarTheme::nativeTheme()->themeChanged();
RECT windowRect;
::GetClientRect(hWnd, &windowRect);
::InvalidateRect(hWnd, &windowRect, false);
#if USE(ACCELERATED_COMPOSITING)
if (webView->isAcceleratedCompositing())
webView->setRootLayerNeedsDisplay();
#endif
}
break;
case WM_MOUSEACTIVATE:
webView->setMouseActivated(true);
handled = false;
break;
case WM_GETDLGCODE: {
COMPtr<IWebUIDelegate> uiDelegate;
COMPtr<IWebUIDelegatePrivate> uiDelegatePrivate;
LONG_PTR dlgCode = 0;
UINT keyCode = 0;
if (lParam) {
LPMSG lpMsg = (LPMSG)lParam;
if (lpMsg->message == WM_KEYDOWN)
keyCode = (UINT) lpMsg->wParam;
}
if (SUCCEEDED(webView->uiDelegate(&uiDelegate)) && uiDelegate
&& SUCCEEDED(uiDelegate->QueryInterface(IID_IWebUIDelegatePrivate, (void**) &uiDelegatePrivate)) && uiDelegatePrivate
&& SUCCEEDED(uiDelegatePrivate->webViewGetDlgCode(webView, keyCode, &dlgCode)))
return dlgCode;
handled = false;
break;
}
case WM_GETOBJECT:
handled = webView->onGetObject(wParam, lParam, lResult);
break;
case WM_IME_STARTCOMPOSITION:
handled = webView->onIMEStartComposition();
break;
case WM_IME_REQUEST:
lResult = webView->onIMERequest(wParam, lParam);
break;
case WM_IME_COMPOSITION:
handled = webView->onIMEComposition(lParam);
break;
case WM_IME_ENDCOMPOSITION:
handled = webView->onIMEEndComposition();
break;
case WM_IME_CHAR:
handled = webView->onIMEChar(wParam, lParam);
break;
case WM_IME_NOTIFY:
handled = webView->onIMENotify(wParam, lParam, &lResult);
break;
case WM_IME_SELECT:
handled = webView->onIMESelect(wParam, lParam);
break;
case WM_IME_SETCONTEXT:
handled = webView->onIMESetContext(wParam, lParam);
break;
case WM_TIMER:
switch (wParam) {
case UpdateActiveStateTimer:
KillTimer(hWnd, UpdateActiveStateTimer);
webView->updateActiveState();
break;
case DeleteBackingStoreTimer:
webView->deleteBackingStore();
break;
}
break;
case WM_SETCURSOR:
handled = ::SetCursor(webView->m_lastSetCursor);
break;
case WM_VSCROLL:
handled = webView->verticalScroll(wParam, lParam);
break;
case WM_HSCROLL:
handled = webView->horizontalScroll(wParam, lParam);
break;
default:
handled = false;
break;
}
if (!handled)
lResult = DefWindowProc(hWnd, message, wParam, lParam);
// Let the client know whether we consider this message handled.
return (message == WM_KEYDOWN || message == WM_SYSKEYDOWN || message == WM_KEYUP || message == WM_SYSKEYUP) ? !handled : lResult;
}

在32平台，webView仅仅需要实现消息处理函数，然后创建窗口，将其消息处理函数注册给目的窗口

2. 网络事件

32平台是用的curl网络库，通过调用网络库的异步函数, webkit引擎与网络库的接口是ResouceHandler，发起网络请求，需要调用ResouceHandle::start(NetworkingContext* context)，函数当网络事件到达，会调用如下函数:

[cpp] view plain copy

void didReceiveData(CFURLConnectionRef conn, CFDataRef data, CFIndex originalLength, const void* clientInfo)
{
ResourceHandle* handle = static_cast<ResourceHandle*>(const_cast<void*>(clientInfo));
const UInt8* bytes = CFDataGetBytePtr(data);
CFIndex length = CFDataGetLength(data);
LOG(Network, "CFNet - didReceiveData(conn=%p, handle=%p, bytes=%d) (%s)", conn, handle, length, handle->firstRequest().url().string().utf8().data());
if (handle->client())
handle->client()->didReceiveData(handle, (const char*)bytes, length, originalLength);
}

3.timer事件

timer事件的处理类似于设备事件，timer的平台初始化函数：

[cpp] view plain copy

static void initializeOffScreenTimerWindow()
{
if (timerWindowHandle)
return;
WNDCLASSEX wcex;
memset(&wcex, 0, sizeof(WNDCLASSEX));
wcex.cbSize = sizeof(WNDCLASSEX);
wcex.lpfnWndProc = TimerWindowWndProc;
wcex.hInstance = WebCore::instanceHandle();
wcex.lpszClassName = kTimerWindowClassName;
RegisterClassEx(&wcex);
timerWindowHandle = CreateWindow(kTimerWindowClassName, 0, 0,
CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, HWND_MESSAGE, 0, WebCore::instanceHandle(), 0);
timerFiredMessage = RegisterWindowMessage(L"com.apple.WebKit.TimerFired");
}

timer的消息处理函数如下：

[cpp] view plain copy

LRESULT CALLBACK TimerWindowWndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
#if PLATFORM(WIN)
// Windows Media Player has a modal message loop that will deliver messages
// to us at inappropriate times and we will crash if we handle them when
// they are delivered. We repost all messages so that we will get to handle
// them once the modal loop exits.
if (PluginView::isCallingPlugin()) {
PostMessage(hWnd, message, wParam, lParam);
return 0;
}
#endif
if (message == timerFiredMessage) {
InterlockedExchange(&pendingTimers, 0);
processingCustomTimerMessage = true;
sharedTimerFiredFunction();
processingCustomTimerMessage = false;
} else if (message == WM_TIMER) {
if (wParam == sharedTimerID) {
KillTimer(timerWindowHandle, sharedTimerID);
sharedTimerFiredFunction();
} else if (wParam == endHighResTimerID) {
KillTimer(timerWindowHandle, endHighResTimerID);
highResTimerActive = false;
timeEndPeriod(timerResolution);
}
} else
return DefWindowProc(hWnd, message, wParam, lParam);
return 0;
}