/*
 * 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.
 */

#ifndef UserGestureIndicator_h
#define UserGestureIndicator_h

#include "platform/PlatformExport.h"
#include "wtf/Noncopyable.h"
#include "wtf/RefCounted.h"
#include "wtf/RefPtr.h"

namespace blink {

enum ProcessingUserGestureState {
  DefinitelyProcessingNewUserGesture,
  DefinitelyProcessingUserGesture,
  PossiblyProcessingUserGesture,
  DefinitelyNotProcessingUserGesture
};

class PLATFORM_EXPORT UserGestureToken : public RefCounted<UserGestureToken> {
  WTF_MAKE_NONCOPYABLE(UserGestureToken);

 public:
  UserGestureToken() {}
  virtual ~UserGestureToken() {}
  virtual bool hasGestures() const = 0;
  virtual void setOutOfProcess() = 0;
  virtual void setJavascriptPrompt() = 0;
  virtual void setPauseInDebugger() = 0;
};

// Callback to be invoked when the state of a UserGestureIndicator is
// used (only during the scope of a UserGestureIndicator, does
// not flow with the UserGestureToken).  It's the responsibility of the
// caller to ensure the UserGestureUtilizedCallback is kept alive as long
// as the UserGestureIndicator it's used in.
// Note that this doesn't currently track EVERY way in which the
// state of a UserGesture can be read (sometimes it's just propagated
// elsewhere, or otherwise read in a way that's hard to know if it will
// actually be used), but should include the primary use cases.  Therefore
// this is suitable mainly for diagnostics and measurement purposes.
class PLATFORM_EXPORT UserGestureUtilizedCallback {
 public:
  virtual ~UserGestureUtilizedCallback() = default;
  virtual void userGestureUtilized() = 0;
};

class PLATFORM_EXPORT UserGestureIndicator final {
  USING_FAST_MALLOC(UserGestureIndicator);
  WTF_MAKE_NONCOPYABLE(UserGestureIndicator);

 public:
  // Returns whether a user gesture is currently in progress.
  // Does not invoke the UserGestureUtilizedCallback.  Consider calling
  // utilizeUserGesture instead if you know for sure that the return value
  // will have an effect.
  static bool processingUserGesture();

  // Indicates that a user gesture (if any) is being used, without preventing it
  // from being used again.  Returns whether a user gesture is currently in
  // progress.  If true, invokes (and then clears) any
  // UserGestureUtilizedCallback.
  static bool utilizeUserGesture();

  // Mark the current user gesture (if any) as having been used, such that
  // it cannot be used again.  This is done only for very security-sensitive
  // operations like creating a new process.
  // Like utilizeUserGesture, may invoke/clear any UserGestureUtilizedCallback.
  static bool consumeUserGesture();

  static UserGestureToken* currentToken();

  // Reset the notion of "since load".
  static void clearProcessedUserGestureSinceLoad();

  // Returns whether a user gesture has occurred since page load.
  static bool processedUserGestureSinceLoad();

  explicit UserGestureIndicator(ProcessingUserGestureState,
                                UserGestureUtilizedCallback* = 0);
  explicit UserGestureIndicator(PassRefPtr<UserGestureToken>,
                                UserGestureUtilizedCallback* = 0);
  ~UserGestureIndicator();

 private:
  static ProcessingUserGestureState s_state;
  static UserGestureIndicator* s_topmostIndicator;
  static bool s_processedUserGestureSinceLoad;
  ProcessingUserGestureState m_previousState;
  RefPtr<UserGestureToken> m_token;
  UserGestureUtilizedCallback* m_usageCallback;
};

}  // namespace blink

#endif