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      1 /*
      2  * Copyright (C) 2011 Google Inc. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions are
      6  * met:
      7  *
      8  *     * Redistributions of source code must retain the above copyright
      9  * notice, this list of conditions and the following disclaimer.
     10  *     * Redistributions in binary form must reproduce the above
     11  * copyright notice, this list of conditions and the following disclaimer
     12  * in the documentation and/or other materials provided with the
     13  * distribution.
     14  *     * Neither the name of Google Inc. nor the names of its
     15  * contributors may be used to endorse or promote products derived from
     16  * this software without specific prior written permission.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     29  */
     30 
     31 #ifndef WebScopedUserGesture_h
     32 #define WebScopedUserGesture_h
     33 
     34 #include "../platform/WebPrivateOwnPtr.h"
     35 
     36 namespace WebCore {
     37 class UserGestureIndicator;
     38 }
     39 
     40 namespace WebKit {
     41 
     42 class WebUserGestureToken;
     43 
     44 // An instance of this class, while kept alive, will indicate that we are in
     45 // the context of a known user gesture. To use, create one, perform whatever
     46 // actions were done under color of a known user gesture, and then delete it.
     47 // Usually this will be done on the stack.
     48 //
     49 // SECURITY WARNING: Do not create several instances of this class for the same
     50 // user gesture. Doing so might enable malicious code to work around certain
     51 // restrictions such as opening multiple windows.
     52 // Instead, obtain the current WebUserGestureToken from the
     53 // WebUserGestureIndicator, and use this token to create a
     54 // WebScopedUserGesture. If the token was alrady consumed, the new
     55 // WebScopedUserGesture will not indicate that we are in the context of a user
     56 // gesture.
     57 class WebScopedUserGesture {
     58 public:
     59     explicit WebScopedUserGesture(const WebUserGestureToken& token) { initializeWithToken(token); }
     60     WebScopedUserGesture() { initialize(); }
     61     ~WebScopedUserGesture() { reset(); }
     62 
     63 private:
     64     WEBKIT_EXPORT void initialize();
     65     WEBKIT_EXPORT void initializeWithToken(const WebUserGestureToken&);
     66     WEBKIT_EXPORT void reset();
     67 
     68     WebPrivateOwnPtr<WebCore::UserGestureIndicator> m_indicator;
     69 };
     70 
     71 } // namespace WebKit
     72 
     73 #endif // WebScopedUserGesture_h
     74