Add EventHandlerRegistry

Source/core/dom/EventHandlerRegistry.cpp

+// Copyright 2014 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 "config.h"
+#include "core/dom/EventHandlerRegistry.h"
+
+#include "core/dom/Document.h"
+#include "core/events/ThreadLocalEventNames.h"
+#include "core/events/WheelEvent.h"
+#include "core/frame/FrameHost.h"
+#include "core/frame/LocalFrame.h"
+#include "core/page/Chrome.h"
+#include "core/page/ChromeClient.h"
+#include "core/page/Page.h"
+#include "core/page/scrolling/ScrollingCoordinator.h"
+
+namespace WebCore {
+
+EventHandlerRegistry::HandlerState::HandlerState()
+{
+}
+
+EventHandlerRegistry::HandlerState::~HandlerState()
+{
+}
+
+EventHandlerRegistry::EventHandlerRegistry(Document& document)
+    : m_document(document)
+{
+}
+
+EventHandlerRegistry::~EventHandlerRegistry()
+{
+}
+
+const char* EventHandlerRegistry::supplementName()
+{
+    return "EventHandlerRegistry";
+}
+
+EventHandlerRegistry* EventHandlerRegistry::from(Document& document)
+{
+    EventHandlerRegistry* registry = static_cast<EventHandlerRegistry*>(DocumentSupplement::from(document, supplementName()));
+    if (!registry) {
+        registry = new EventHandlerRegistry(document);
+        DocumentSupplement::provideTo(document, supplementName(), adoptPtr(registry));
+    }
+    return registry;
+}
+
+bool EventHandlerRegistry::eventTypeToClass(const AtomicString& eventType, EventHandlerClass* result)
+{
+    if (eventType == EventTypeNames::scroll) {
+        *result = ScrollEvent;
+    } else {
+        return false;
+    }
+    return true;
+}
+
+const EventTargetSet* EventHandlerRegistry::eventHandlerTargets(EventHandlerClass handlerClass) const
+{
+    return m_eventHandlers[handlerClass].targets.get();
+}
+
+bool EventHandlerRegistry::hasEventHandlers(EventHandlerClass handlerClass) const
+{
+    EventTargetSet* targets = m_eventHandlers[handlerClass].targets.get();
+    return targets && targets->size();
+}
+
+bool EventHandlerRegistry::updateEventHandlerTargets(ChangeOperation op, EventHandlerClass handlerClass, EventTarget* target)
+{
+    EventTargetSet* targets = m_eventHandlers[handlerClass].targets.get();
+    if (op == Add) {
+#if ASSERT_ENABLED
+        if (Node* node = target->toNode())
+            ASSERT(&node->document() == &m_document);
+#endif // ASSERT_ENABLED
+
+        if (!targets) {
+            m_eventHandlers[handlerClass].targets = adoptPtr(new EventTargetSet);
+            targets = m_eventHandlers[handlerClass].targets.get();
+        }
+
+        if (!targets->add(target).isNewEntry) {
+            // Just incremented refcount, no real change.
+            return false;
+        }
+    } else {
+        // Note that we can't assert that |target| is in this document because
+        // it might be in the process of moving out of it.
+        ASSERT(op == Remove || op == RemoveAll);
+        ASSERT(op == RemoveAll || targets->contains(target));
+        if (!targets)
+            return false;
+
+        if (op == RemoveAll) {
+            if (!targets->contains(target))
+                return false;
+            targets->removeAll(target);
+        } else {
+            if (!targets->remove(target)) {
+                // Just decremented refcount, no real update.
+                return false;
+            }
+        }
+    }
+    return true;
+}
+
+void EventHandlerRegistry::updateEventHandlerInternal(ChangeOperation op, EventHandlerClass handlerClass, EventTarget* target)
+{
+    // After the document has stopped, all updates become no-ops.
+    if (!m_document.isActive()) {
+        return;
+    }
+
+    bool hadHandlers = hasEventHandlers(handlerClass);
+    updateEventHandlerTargets(op, handlerClass, target);
+    bool hasHandlers = hasEventHandlers(handlerClass);
+
+    // Notify the parent document's registry if we added the first or removed
+    // the last handler.
+    if (hadHandlers != hasHandlers && !m_document.parentDocument()) {
+        // This is the root registry; notify clients accordingly.
+        notifyHasHandlersChanged(handlerClass, hasHandlers);
+    }
+}
+
+void EventHandlerRegistry::updateEventHandlerOfType(ChangeOperation op, const AtomicString& eventType, EventTarget* target)
+{
+    EventHandlerClass handlerClass;
+    if (!eventTypeToClass(eventType, &handlerClass))
+        return;
+    updateEventHandlerInternal(op, handlerClass, target);
+}
+
+void EventHandlerRegistry::didAddEventHandler(EventTarget& target, const AtomicString& eventType)
+{
+    updateEventHandlerOfType(Add, eventType, &target);
+}
+
+void EventHandlerRegistry::didRemoveEventHandler(EventTarget& target, const AtomicString& eventType)
+{
+    updateEventHandlerOfType(Remove, eventType, &target);
+}
+
+void EventHandlerRegistry::didAddEventHandler(EventTarget& target, EventHandlerClass handlerClass)
+{
+    updateEventHandlerInternal(Add, handlerClass, &target);
+}
+
+void EventHandlerRegistry::didRemoveEventHandler(EventTarget& target, EventHandlerClass handlerClass)
+{
+    updateEventHandlerInternal(Remove, handlerClass, &target);
+}
+
+void EventHandlerRegistry::didMoveFromOtherDocument(EventTarget& target, Document& oldDocument)
+{
+    EventHandlerRegistry* oldRegistry = EventHandlerRegistry::from(oldDocument);
+    for (size_t i = 0; i < EventHandlerClassCount; ++i) {
+        EventHandlerClass handlerClass = static_cast<EventHandlerClass>(i);
+        const EventTargetSet* targets = oldRegistry->eventHandlerTargets(handlerClass);
+        if (!targets)
+            continue;
+        for (unsigned count = targets->count(&target); count > 0; --count) {
+            oldRegistry->updateEventHandlerInternal(Remove, handlerClass, &target);
+            updateEventHandlerInternal(Add, handlerClass, &target);
+        }
+    }
+}
+
+void EventHandlerRegistry::didRemoveAllEventHandlers(EventTarget& target)
+{
+    for (size_t i = 0; i < EventHandlerClassCount; ++i) {
+        EventHandlerClass handlerClass = static_cast<EventHandlerClass>(i);
+        const EventTargetSet* targets = eventHandlerTargets(handlerClass);
+        if (!targets)
+            continue;
+        updateEventHandlerInternal(RemoveAll, handlerClass, &target);
+    }
+}
+
+void EventHandlerRegistry::notifyHasHandlersChanged(EventHandlerClass handlerClass, bool hasActiveHandlers)
+{
+    Page* page = m_document.page();
+    ScrollingCoordinator* scrollingCoordinator = page ? page->scrollingCoordinator() : 0;
+
+    switch (handlerClass) {
+    case ScrollEvent:
+        if (scrollingCoordinator)
+            scrollingCoordinator->updateHaveScrollEventHandlers();
+        break;
+    default:
+        ASSERT_NOT_REACHED();
+        break;
+    }
+}
+
+} // namespace WebCore