third_party/WebKit/Source/platform/UserGestureIndicator.cpp

/*
 * Copyright (C) 2010 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "platform/UserGestureIndicator.h"

#include "wtf/Assertions.h"
#include "wtf/CurrentTime.h"

namespace blink {

namespace {

// User gestures timeout in 1 second.
const double userGestureTimeout = 1.0;

// For out of process tokens we allow a 10 second delay.
const double userGestureOutOfProcessTimeout = 10.0;

class GestureToken final : public UserGestureToken {
  WTF_MAKE_NONCOPYABLE(GestureToken);

 public:
  static PassRefPtr<UserGestureToken> create() {
    return adoptRef(new GestureToken);
  }

  ~GestureToken() final {}

  bool hasGestures() const override {
    // Do not enforce timeouts for gestures which spawned javascript prompts or
    // debugger pause.
    if (m_consumableGestures < 1 ||
        (!m_javascriptPrompt && !m_pauseInDebugger &&
         hasTimedOut(m_outOfProcess ? userGestureOutOfProcessTimeout
                                    : userGestureTimeout)))
      return false;
    return true;
  }

  void addGesture() {
    m_consumableGestures++;
    m_timestamp = WTF::currentTime();
  }

  void resetTimestamp() { m_timestamp = WTF::currentTime(); }

  bool consumeGesture() {
    if (!m_consumableGestures)
      return false;
    m_consumableGestures--;
    return true;
  }

  void setOutOfProcess() final {
    if (!hasTimedOut(userGestureTimeout) && hasGestures())
      m_outOfProcess = true;
  }

  void setJavascriptPrompt() final {
    if (!hasTimedOut(userGestureTimeout) && hasGestures())
      m_javascriptPrompt = true;
  }

  void setPauseInDebugger() final {
    if (!hasTimedOut(userGestureTimeout) && hasGestures())
      m_pauseInDebugger = true;
  }

 private:
  GestureToken()
      : m_consumableGestures(0),
        m_timestamp(0),
        m_outOfProcess(false),
        m_javascriptPrompt(false),
        m_pauseInDebugger(false) {}

  bool hasTimedOut(double timeout) const {
    return WTF::currentTime() - m_timestamp > timeout;
  }

  size_t m_consumableGestures;
  double m_timestamp;
  bool m_outOfProcess;
  bool m_javascriptPrompt;
  bool m_pauseInDebugger;
};

bool isDefinite(ProcessingUserGestureState state) {
  return state == DefinitelyProcessingNewUserGesture ||
         state == DefinitelyProcessingUserGesture ||
         state == DefinitelyNotProcessingUserGesture;
}

bool isDefiniteUserGesture(ProcessingUserGestureState state) {
  return state == DefinitelyProcessingNewUserGesture ||
         state == DefinitelyProcessingUserGesture;
}

}  // namespace

ProcessingUserGestureState UserGestureIndicator::s_state =
    DefinitelyNotProcessingUserGesture;
UserGestureIndicator* UserGestureIndicator::s_topmostIndicator = 0;
bool UserGestureIndicator::s_processedUserGestureSinceLoad = false;

UserGestureIndicator::UserGestureIndicator(
    ProcessingUserGestureState state,
    UserGestureUtilizedCallback* usageCallback)
    : m_previousState(DefinitelyNotProcessingUserGesture),
      m_usageCallback(usageCallback) {
  // Silently ignore UserGestureIndicators on non-main threads.
  if (!isMainThread())
    return;

  m_previousState = s_state;

  // We overwrite s_state only if the caller is definite about the gesture
  // state.
  if (isDefinite(state)) {
    if (!s_topmostIndicator) {
      s_topmostIndicator = this;
      m_token = GestureToken::create();
    } else {
      m_token = currentToken();
    }
    s_state = state;
  }

  if (state == DefinitelyProcessingNewUserGesture) {
    static_cast<GestureToken*>(m_token.get())->addGesture();
    s_processedUserGestureSinceLoad = true;
  } else if (state == DefinitelyProcessingUserGesture &&
             s_topmostIndicator == this) {
    static_cast<GestureToken*>(m_token.get())->addGesture();
    s_processedUserGestureSinceLoad = true;
  }
  ASSERT(isDefinite(s_state));
}

UserGestureIndicator::UserGestureIndicator(
    PassRefPtr<UserGestureToken> token,
    UserGestureUtilizedCallback* usageCallback)
    : m_previousState(DefinitelyNotProcessingUserGesture),
      m_usageCallback(usageCallback) {
  // Silently ignore UserGestureIndicators on non-main threads.
  if (!isMainThread())
    return;

  m_previousState = s_state;

  if (token) {
    static_cast<GestureToken*>(token.get())->resetTimestamp();
    if (!s_topmostIndicator) {
      s_topmostIndicator = this;
      m_token = token;
    } else {
      m_token = currentToken();
      if (static_cast<GestureToken*>(token.get())->hasGestures()) {
        static_cast<GestureToken*>(m_token.get())->addGesture();
        static_cast<GestureToken*>(token.get())->consumeGesture();
      }
    }
    s_state = DefinitelyProcessingUserGesture;
  }

  ASSERT(isDefinite(s_state));
}

UserGestureIndicator::~UserGestureIndicator() {
  if (!isMainThread())
    return;
  s_state = m_previousState;
  if (s_topmostIndicator == this)
    s_topmostIndicator = nullptr;
  ASSERT(isDefinite(s_state));
}

// static
bool UserGestureIndicator::utilizeUserGesture() {
  if (UserGestureIndicator::processingUserGesture()) {
    if (s_topmostIndicator->m_usageCallback) {
      s_topmostIndicator->m_usageCallback->userGestureUtilized();
      s_topmostIndicator->m_usageCallback = nullptr;
    }
    return true;
  }
  return false;
}

bool UserGestureIndicator::processingUserGesture() {
  if (auto* token = currentToken()) {
    ASSERT(isMainThread());
    return isDefiniteUserGesture(s_state) &&
           static_cast<GestureToken*>(token)->hasGestures();
  }

  return false;
}

// static
bool UserGestureIndicator::consumeUserGesture() {
  if (auto* token = currentToken()) {
    ASSERT(isMainThread());
    if (static_cast<GestureToken*>(token)->consumeGesture()) {
      if (s_topmostIndicator->m_usageCallback) {
        s_topmostIndicator->m_usageCallback->userGestureUtilized();
        s_topmostIndicator->m_usageCallback = nullptr;
      }
      return true;
    }
  }
  return false;
}

// static
UserGestureToken* UserGestureIndicator::currentToken() {
  if (!isMainThread() || !s_topmostIndicator)
    return nullptr;
  return s_topmostIndicator->m_token.get();
}

// static
void UserGestureIndicator::clearProcessedUserGestureSinceLoad() {
  if (isMainThread())
    s_processedUserGestureSinceLoad = false;
}

// static
bool UserGestureIndicator::processedUserGestureSinceLoad() {
  if (!isMainThread())
    return false;
  return s_processedUserGestureSinceLoad;
}

}  // namespace blink