third_party/WebKit/Source/core/events/Event.cpp

/*
 * Copyright (C) 2001 Peter Kelly (pmk@post.com)
 * Copyright (C) 2001 Tobias Anton (anton@stud.fbi.fh-darmstadt.de)
 * Copyright (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
 * Copyright (C) 2003, 2005, 2006, 2008 Apple Inc. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

#include "core/events/Event.h"

#include "core/dom/StaticNodeList.h"
#include "core/events/EventDispatchMediator.h"
#include "core/events/EventTarget.h"
#include "core/frame/HostsUsingFeatures.h"
#include "core/frame/UseCounter.h"
#include "core/svg/SVGElement.h"
#include "core/timing/DOMWindowPerformance.h"
#include "core/timing/Performance.h"
#include "wtf/CurrentTime.h"

namespace blink {

static bool isEventTypeScopedInV0(const AtomicString& eventType) {
  // WebKit never allowed selectstart event to cross the the shadow DOM
  // boundary.  Changing this breaks existing sites.
  // See https://bugs.webkit.org/show_bug.cgi?id=52195 for details.
  return eventType == EventTypeNames::abort ||
         eventType == EventTypeNames::change ||
         eventType == EventTypeNames::error ||
         eventType == EventTypeNames::load ||
         eventType == EventTypeNames::reset ||
         eventType == EventTypeNames::resize ||
         eventType == EventTypeNames::scroll ||
         eventType == EventTypeNames::select ||
         eventType == EventTypeNames::selectstart ||
         eventType == EventTypeNames::slotchange;
}

Event::Event() : Event("", false, false) {
  m_wasInitialized = false;
}

Event::Event(const AtomicString& eventType,
             bool canBubbleArg,
             bool cancelableArg,
             double platformTimeStamp)
    : Event(eventType,
            canBubbleArg,
            cancelableArg,
            ComposedMode::Scoped,
            platformTimeStamp) {}

Event::Event(const AtomicString& eventType,
             bool canBubbleArg,
             bool cancelableArg,
             ComposedMode composedMode)
    : Event(eventType,
            canBubbleArg,
            cancelableArg,
            composedMode,
            monotonicallyIncreasingTime()) {}

Event::Event(const AtomicString& eventType,
             bool canBubbleArg,
             bool cancelableArg,
             ComposedMode composedMode,
             double platformTimeStamp)
    : m_type(eventType),
      m_canBubble(canBubbleArg),
      m_cancelable(cancelableArg),
      m_composed(composedMode == ComposedMode::Composed),
      m_isEventTypeScopedInV0(isEventTypeScopedInV0(eventType)),
      m_propagationStopped(false),
      m_immediatePropagationStopped(false),
      m_defaultPrevented(false),
      m_defaultHandled(false),
      m_cancelBubble(false),
      m_wasInitialized(true),
      m_isTrusted(false),
      m_preventDefaultCalledOnUncancelableEvent(false),
      m_handlingPassive(PassiveMode::NotPassive),
      m_eventPhase(0),
      m_currentTarget(nullptr),
      m_platformTimeStamp(platformTimeStamp) {}

Event::Event(const AtomicString& eventType, const EventInit& initializer)
    : Event(eventType,
            initializer.bubbles(),
            initializer.cancelable(),
            initializer.composed() ? ComposedMode::Composed
                                   : ComposedMode::Scoped,
            monotonicallyIncreasingTime()) {}

Event::~Event() {}

bool Event::isScopedInV0() const {
  return isTrusted() && m_isEventTypeScopedInV0;
}

void Event::initEvent(const AtomicString& eventTypeArg,
                      bool canBubbleArg,
                      bool cancelableArg) {
  initEvent(eventTypeArg, canBubbleArg, cancelableArg, nullptr);
}

void Event::initEvent(const AtomicString& eventTypeArg,
                      bool canBubbleArg,
                      bool cancelableArg,
                      EventTarget* relatedTarget) {
  if (isBeingDispatched())
    return;

  m_wasInitialized = true;
  m_propagationStopped = false;
  m_immediatePropagationStopped = false;
  m_defaultPrevented = false;
  m_isTrusted = false;
  m_preventDefaultCalledOnUncancelableEvent = false;

  m_type = eventTypeArg;
  m_canBubble = canBubbleArg;
  m_cancelable = cancelableArg;
}

bool Event::legacyReturnValue(ExecutionContext* executionContext) const {
  bool returnValue = !defaultPrevented();
  if (returnValue)
    UseCounter::count(executionContext, UseCounter::EventGetReturnValueTrue);
  else
    UseCounter::count(executionContext, UseCounter::EventGetReturnValueFalse);
  return returnValue;
}

void Event::setLegacyReturnValue(ExecutionContext* executionContext,
                                 bool returnValue) {
  if (returnValue)
    UseCounter::count(executionContext, UseCounter::EventSetReturnValueTrue);
  else
    UseCounter::count(executionContext, UseCounter::EventSetReturnValueFalse);
  setDefaultPrevented(!returnValue);
}

const AtomicString& Event::interfaceName() const {
  return EventNames::Event;
}

bool Event::hasInterface(const AtomicString& name) const {
  return interfaceName() == name;
}

bool Event::isUIEvent() const {
  return false;
}

bool Event::isMouseEvent() const {
  return false;
}

bool Event::isFocusEvent() const {
  return false;
}

bool Event::isKeyboardEvent() const {
  return false;
}

bool Event::isTouchEvent() const {
  return false;
}

bool Event::isGestureEvent() const {
  return false;
}

bool Event::isWheelEvent() const {
  return false;
}

bool Event::isRelatedEvent() const {
  return false;
}

bool Event::isPointerEvent() const {
  return false;
}

bool Event::isInputEvent() const {
  return false;
}

bool Event::isDragEvent() const {
  return false;
}

bool Event::isClipboardEvent() const {
  return false;
}

bool Event::isBeforeTextInsertedEvent() const {
  return false;
}

bool Event::isBeforeUnloadEvent() const {
  return false;
}

void Event::preventDefault() {
  if (m_handlingPassive != PassiveMode::NotPassive) {
    m_preventDefaultCalledDuringPassive = true;

    const LocalDOMWindow* window =
        m_eventPath ? m_eventPath->windowEventContext().window() : 0;
    if (window) {
      const char* devToolsMsg = nullptr;
      switch (m_handlingPassive) {
        case PassiveMode::NotPassive:
          NOTREACHED();
          break;
        case PassiveMode::Passive:
          devToolsMsg =
              "Unable to preventDefault inside passive event listener "
              "invocation.";
          break;
        case PassiveMode::PassiveForcedDocumentLevel:
          devToolsMsg =
              "Unable to preventDefault inside passive event listener due to "
              "target being treated as passive. See "
              "https://www.chromestatus.com/features/5093566007214080";
          break;
      }
      if (devToolsMsg)
        window->printErrorMessage(devToolsMsg);
    }
    return;
  }

  if (m_cancelable)
    m_defaultPrevented = true;
  else
    m_preventDefaultCalledOnUncancelableEvent = true;
}

void Event::setTarget(EventTarget* target) {
  if (m_target == target)
    return;

  m_target = target;
  if (m_target)
    receivedTarget();
}

void Event::receivedTarget() {}

void Event::setUnderlyingEvent(Event* ue) {
  // Prohibit creation of a cycle -- just do nothing in that case.
  for (Event* e = ue; e; e = e->underlyingEvent())
    if (e == this)
      return;
  m_underlyingEvent = ue;
}

void Event::initEventPath(Node& node) {
  if (!m_eventPath) {
    m_eventPath = new EventPath(node, this);
  } else {
    m_eventPath->initializeWith(node, this);
  }
}

HeapVector<Member<EventTarget>> Event::path(ScriptState* scriptState) const {
  return pathInternal(scriptState, NonEmptyAfterDispatch);
}

HeapVector<Member<EventTarget>> Event::composedPath(
    ScriptState* scriptState) const {
  return pathInternal(scriptState, EmptyAfterDispatch);
}

void Event::setHandlingPassive(PassiveMode mode) {
  m_handlingPassive = mode;
  m_preventDefaultCalledDuringPassive = false;
}

HeapVector<Member<EventTarget>> Event::pathInternal(ScriptState* scriptState,
                                                    EventPathMode mode) const {
  if (m_target)
    HostsUsingFeatures::countHostOrIsolatedWorldHumanReadableName(
        scriptState, *m_target, HostsUsingFeatures::Feature::EventPath);

  if (!m_currentTarget) {
    DCHECK_EQ(Event::kNone, m_eventPhase);
    if (!m_eventPath) {
      // Before dispatching the event
      return HeapVector<Member<EventTarget>>();
    }
    DCHECK(!m_eventPath->isEmpty());
    // After dispatching the event
    if (mode == EmptyAfterDispatch)
      return HeapVector<Member<EventTarget>>();
    return m_eventPath->last().treeScopeEventContext().ensureEventPath(
        *m_eventPath);
  }

  if (Node* node = m_currentTarget->toNode()) {
    DCHECK(m_eventPath);
    size_t eventPathSize = m_eventPath->size();
    for (size_t i = 0; i < eventPathSize; ++i) {
      if (node == (*m_eventPath)[i].node()) {
        return (*m_eventPath)[i].treeScopeEventContext().ensureEventPath(
            *m_eventPath);
      }
    }
    NOTREACHED();
  }

  if (LocalDOMWindow* window = m_currentTarget->toLocalDOMWindow()) {
    if (m_eventPath && !m_eventPath->isEmpty()) {
      return m_eventPath->topNodeEventContext()
          .treeScopeEventContext()
          .ensureEventPath(*m_eventPath);
    }
    return HeapVector<Member<EventTarget>>(1, window);
  }

  return HeapVector<Member<EventTarget>>();
}

EventDispatchMediator* Event::createMediator() {
  return EventDispatchMediator::create(this);
}

double Event::timeStamp(ScriptState* scriptState) const {
  double timeStamp = 0;
  if (scriptState && scriptState->domWindow()) {
    Performance* performance =
        DOMWindowPerformance::performance(*scriptState->domWindow());
    timeStamp =
        performance->monotonicTimeToDOMHighResTimeStamp(m_platformTimeStamp);
  }

  return timeStamp;
}

void Event::setCancelBubble(ExecutionContext* context, bool cancel) {
  if (!m_cancelBubble && cancel)
    UseCounter::count(context, UseCounter::EventCancelBubbleWasChangedToTrue);
  else if (m_cancelBubble && !cancel)
    UseCounter::count(context, UseCounter::EventCancelBubbleWasChangedToFalse);
  m_cancelBubble = cancel;
}

DEFINE_TRACE(Event) {
  visitor->trace(m_currentTarget);
  visitor->trace(m_target);
  visitor->trace(m_underlyingEvent);
  visitor->trace(m_eventPath);
}

}  // namespace blink