Creat a KeyboardEventManager class

third_party/WebKit/Source/core/input/KeyboardEventManager.cpp

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "KeyboardEventManager.h"
+
+#include "core/dom/Element.h"
+#include "core/editing/Editor.h"
+#include "core/events/KeyboardEvent.h"
+#include "core/html/HTMLDialogElement.h"
+#include "core/input/EventHandler.h"
+#include "core/layout/LayoutObject.h"
+#include "core/layout/LayoutTextControlSingleLine.h"
+#include "core/loader/FrameLoaderClient.h"
+#include "core/page/ChromeClient.h"
+#include "core/page/FocusController.h"
+#include "core/page/Page.h"
+#include "core/page/SpatialNavigation.h"
+#include "platform/PlatformKeyboardEvent.h"
+#include "platform/UserGestureIndicator.h"
+#include "platform/WindowsKeyboardCodes.h"
+
+namespace blink {
+
+namespace {
+
+WebFocusType focusDirectionForKey(const AtomicString& keyIdentifier)
+{
+    DEFINE_STATIC_LOCAL(AtomicString, Down, ("Down"));
+    DEFINE_STATIC_LOCAL(AtomicString, Up, ("Up"));
+    DEFINE_STATIC_LOCAL(AtomicString, Left, ("Left"));
+    DEFINE_STATIC_LOCAL(AtomicString, Right, ("Right"));
+
+    WebFocusType retVal = WebFocusTypeNone;
+
+    if (keyIdentifier == Down)
+        retVal = WebFocusTypeDown;
+    else if (keyIdentifier == Up)
+        retVal = WebFocusTypeUp;
+    else if (keyIdentifier == Left)
+        retVal = WebFocusTypeLeft;
+    else if (keyIdentifier == Right)
+        retVal = WebFocusTypeRight;
+
+    return retVal;
+}
+
+} // namespace
+
+KeyboardEventManager::KeyboardEventManager(
+    LocalFrame* frame, ScrollManager* scrollManager)
+: m_frame(frame)
+, m_scrollManager(scrollManager)
+{
+}
+
+KeyboardEventManager::~KeyboardEventManager()
+{
+}
+
+bool KeyboardEventManager::handleAccessKey(const PlatformKeyboardEvent& evt)
+{
+    // FIXME: Ignoring the state of Shift key is what neither IE nor Firefox do.
+    // IE matches lower and upper case access keys regardless of Shift key state - but if both upper and
+    // lower case variants are present in a document, the correct element is matched based on Shift key state.
+    // Firefox only matches an access key if Shift is not pressed, and does that case-insensitively.
+    DCHECK(!(PlatformKeyboardEvent::accessKeyModifiers() & PlatformEvent::ShiftKey));
+    if ((evt.getModifiers() & (PlatformEvent::KeyModifiers & ~PlatformEvent::ShiftKey)) != PlatformKeyboardEvent::accessKeyModifiers())
+        return false;
+    String key = evt.unmodifiedText();
+    Element* elem = m_frame->document()->getElementByAccessKey(key.lower());
+    if (!elem)
+        return false;
+    elem->accessKeyAction(false);
+    return true;
+}
+
+WebInputEventResult KeyboardEventManager::keyEvent(
+    const PlatformKeyboardEvent& initialKeyEvent)
+{
+    m_frame->chromeClient().clearToolTip();
+
+    if (initialKeyEvent.windowsVirtualKeyCode() == VK_CAPITAL)
+        capsLockStateMayHaveChanged();
+
+#if OS(WIN)
+    if (m_scrollManager->panScrollInProgress()) {
+        // If a key is pressed while the panScroll is in progress then we want to stop
+        if (initialKeyEvent.type() == PlatformEvent::KeyDown || initialKeyEvent.type() == PlatformEvent::RawKeyDown)
+            m_scrollManager->stopAutoscroll();
+
+        // If we were in panscroll mode, we swallow the key event
+        return WebInputEventResult::HandledSuppressed;
+    }
+#endif
+
+    // Check for cases where we are too early for events -- possible unmatched key up
+    // from pressing return in the location bar.
+    Node* node = eventTargetNodeForDocument(m_frame->document());
+    if (!node)
+        return WebInputEventResult::NotHandled;
+
+    UserGestureIndicator gestureIndicator(DefinitelyProcessingUserGesture);
+
+    // In IE, access keys are special, they are handled after default keydown processing, but cannot be canceled - this is hard to match.
+    // On Mac OS X, we process them before dispatching keydown, as the default keydown handler implements Emacs key bindings, which may conflict
+    // with access keys. Then we dispatch keydown, but suppress its default handling.
+    // On Windows, WebKit explicitly calls handleAccessKey() instead of dispatching a keypress event for WM_SYSCHAR messages.
+    // Other platforms currently match either Mac or Windows behavior, depending on whether they send combined KeyDown events.
+    bool matchedAnAccessKey = false;
+    if (initialKeyEvent.type() == PlatformEvent::KeyDown)
+        matchedAnAccessKey = handleAccessKey(initialKeyEvent);
+
+    // FIXME: it would be fair to let an input method handle KeyUp events before DOM dispatch.
+    if (initialKeyEvent.type() == PlatformEvent::KeyUp || initialKeyEvent.type() == PlatformEvent::Char) {
+        KeyboardEvent* domEvent = KeyboardEvent::create(initialKeyEvent, m_frame->document()->domWindow());
+
+        return EventHandler::toWebInputEventResult(node->dispatchEvent(domEvent));
+    }
+
+    PlatformKeyboardEvent keyDownEvent = initialKeyEvent;
+    if (keyDownEvent.type() != PlatformEvent::RawKeyDown)
+        keyDownEvent.disambiguateKeyDownEvent(PlatformEvent::RawKeyDown);
+    KeyboardEvent* keydown = KeyboardEvent::create(keyDownEvent, m_frame->document()->domWindow());
+    if (matchedAnAccessKey)
+        keydown->setDefaultPrevented(true);
+    keydown->setTarget(node);
+
+    DispatchEventResult dispatchResult = node->dispatchEvent(keydown);
+    if (dispatchResult != DispatchEventResult::NotCanceled)
+        return EventHandler::toWebInputEventResult(dispatchResult);
+    // If frame changed as a result of keydown dispatch, then return early to avoid sending a subsequent keypress message to the new frame.
+    bool changedFocusedFrame = m_frame->page() && m_frame != m_frame->page()->focusController().focusedOrMainFrame();
+    if (changedFocusedFrame)
+        return WebInputEventResult::HandledSystem;
+
+    if (initialKeyEvent.type() == PlatformEvent::RawKeyDown)
+        return WebInputEventResult::NotHandled;
+
+    // Focus may have changed during keydown handling, so refetch node.
+    // But if we are dispatching a fake backward compatibility keypress, then we pretend that the keypress happened on the original node.
+    node = eventTargetNodeForDocument(m_frame->document());
+    if (!node)
+        return WebInputEventResult::NotHandled;
+
+    PlatformKeyboardEvent keyPressEvent = initialKeyEvent;
+    keyPressEvent.disambiguateKeyDownEvent(PlatformEvent::Char);
+    if (keyPressEvent.text().isEmpty())
+        return WebInputEventResult::NotHandled;
+    KeyboardEvent* keypress = KeyboardEvent::create(keyPressEvent, m_frame->document()->domWindow());
+    keypress->setTarget(node);
+    return EventHandler::toWebInputEventResult(node->dispatchEvent(keypress));
+}
+
+void KeyboardEventManager::capsLockStateMayHaveChanged()
+{
+    if (Element* element = m_frame->document()->focusedElement()) {
+        if (LayoutObject* r = element->layoutObject()) {
+            if (r->isTextField())
+                toLayoutTextControlSingleLine(r)->capsLockStateMayHaveChanged();
+        }
+    }
+}
+
+void KeyboardEventManager::defaultKeyboardEventHandler(
+    KeyboardEvent* event, Node* possibleFocusedNode)
+{
+    if (event->type() == EventTypeNames::keydown) {
+        // Clear caret blinking suspended state to make sure that caret blinks
+        // when we type again after long pressing on an empty input field.
+        if (m_frame && m_frame->selection().isCaretBlinkingSuspended())
+            m_frame->selection().setCaretBlinkingSuspended(false);
+
+        m_frame->editor().handleKeyboardEvent(event);
+        if (event->defaultHandled())
+            return;
+        if (event->keyIdentifier() == "U+0009") {
+            defaultTabEventHandler(event);
+        } else if (event->keyIdentifier() == "U+0008") {
+            defaultBackspaceEventHandler(event);
+        } else if (event->keyIdentifier() == "U+001B") {
+            defaultEscapeEventHandler(event);
+        } else {
+            WebFocusType type = focusDirectionForKey(AtomicString(event->keyIdentifier()));
+            if (type != WebFocusTypeNone)
+                defaultArrowEventHandler(type, event);
+        }
+    }
+    if (event->type() == EventTypeNames::keypress) {
+        m_frame->editor().handleKeyboardEvent(event);
+        if (event->defaultHandled())
+            return;
+        if (event->charCode() == ' ')
+            defaultSpaceEventHandler(event, possibleFocusedNode);
+    }
+}
+
+void KeyboardEventManager::defaultSpaceEventHandler(
+    KeyboardEvent* event, Node* possibleFocusedNode)
+{
+    DCHECK_EQ(event->type(), EventTypeNames::keypress);
+
+    if (event->ctrlKey() || event->metaKey() || event->altKey())
+        return;
+
+    ScrollDirection direction = event->shiftKey() ? ScrollBlockDirectionBackward : ScrollBlockDirectionForward;
+
+    // FIXME: enable scroll customization in this case. See crbug.com/410974.
+    if (m_scrollManager->logicalScroll(direction, ScrollByPage, nullptr, possibleFocusedNode)) {
+        event->setDefaultHandled();
+        return;
+    }
+}
+
+void KeyboardEventManager::defaultBackspaceEventHandler(KeyboardEvent* event)
+{
+    DCHECK_EQ(event->type(), EventTypeNames::keydown);
+
+    if (!RuntimeEnabledFeatures::backspaceDefaultHandlerEnabled())
+        return;
+
+    if (event->ctrlKey() || event->metaKey() || event->altKey())
+        return;
+
+    if (!m_frame->editor().behavior().shouldNavigateBackOnBackspace())
+        return;
+    UseCounter::count(m_frame->document(), UseCounter::BackspaceNavigatedBack);
+    if (m_frame->page()->chromeClient().hadFormInteraction())
+        UseCounter::count(m_frame->document(), UseCounter::BackspaceNavigatedBackAfterFormInteraction);
+    bool handledEvent = m_frame->loader().client()->navigateBackForward(event->shiftKey() ? 1 : -1);
+    if (handledEvent)
+        event->setDefaultHandled();
+}
+
+void KeyboardEventManager::defaultArrowEventHandler(WebFocusType focusType, KeyboardEvent* event)
+{
+    DCHECK_EQ(event->type(), EventTypeNames::keydown);
+
+    if (event->ctrlKey() || event->metaKey() || event->shiftKey())
+        return;
+
+    Page* page = m_frame->page();
+    if (!page)
+        return;
+
+    if (!isSpatialNavigationEnabled(m_frame))
+        return;
+
+    // Arrows and other possible directional navigation keys can be used in design
+    // mode editing.
+    if (m_frame->document()->inDesignMode())
+        return;
+
+    if (page->focusController().advanceFocus(focusType))
+        event->setDefaultHandled();
+}
+
+void KeyboardEventManager::defaultTabEventHandler(KeyboardEvent* event)
+{
+    DCHECK_EQ(event->type(), EventTypeNames::keydown);
+
+    // We should only advance focus on tabs if no special modifier keys are held down.
+    if (event->ctrlKey() || event->metaKey())
+        return;
+
+#if !OS(MACOSX)
+    // Option-Tab is a shortcut based on a system-wide preference on Mac but
+    // should be ignored on all other platforms.
+    if (event->altKey())
+        return;
+#endif
+
+    Page* page = m_frame->page();
+    if (!page)
+        return;
+    if (!page->tabKeyCyclesThroughElements())
+        return;
+
+    WebFocusType focusType = event->shiftKey() ? WebFocusTypeBackward : WebFocusTypeForward;
+
+    // Tabs can be used in design mode editing.
+    if (m_frame->document()->inDesignMode())
+        return;
+
+    if (page->focusController().advanceFocus(focusType, InputDeviceCapabilities::doesntFireTouchEventsSourceCapabilities()))
+        event->setDefaultHandled();
+}
+
+void KeyboardEventManager::defaultEscapeEventHandler(KeyboardEvent* event)
+{
+    if (HTMLDialogElement* dialog = m_frame->document()->activeModalDialog())
+        dialog->dispatchEvent(Event::createCancelable(EventTypeNames::cancel));
+}
+
+DEFINE_TRACE(KeyboardEventManager)
+{
+    visitor->trace(m_frame);
+}
+
+} // namespace blink