third_party/WebKit/public/web/WebScopedUserGesture.h

   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 blink {
  37
  38 class UserGestureIndicator;
  39 class WebUserGestureToken;
  40
  41 // An instance of this class, while kept alive, will indicate that we are in
  42 // the context of a known user gesture. To use, create one, perform whatever
  43 // actions were done under color of a known user gesture, and then delete it.
  44 // Usually this will be done on the stack.
  45 //
  46 // SECURITY WARNING: Do not create several instances of this class for the same
  47 // user gesture. Doing so might enable malicious code to work around certain
  48 // restrictions such as opening multiple windows.
  49 // Instead, obtain the current WebUserGestureToken from the
  50 // WebUserGestureIndicator, and use this token to create a
  51 // WebScopedUserGesture. If the token was alrady consumed, the new
  52 // WebScopedUserGesture will not indicate that we are in the context of a user
  53 // gesture.
  54 class WebScopedUserGesture {
  55 public:
  56     explicit WebScopedUserGesture(const WebUserGestureToken& token) { initializeWithToken(token); }
  57     WebScopedUserGesture() { initialize(); }
  58     ~WebScopedUserGesture() { reset(); }
  59
  60 private:
  61     BLINK_EXPORT void initialize();
  62     BLINK_EXPORT void initializeWithToken(const WebUserGestureToken&);
  63     BLINK_EXPORT void reset();
  64
  65     WebPrivateOwnPtr<UserGestureIndicator> m_indicator;
  66 };
  67
  68 } // namespace blink
  69
  70 #endif // WebScopedUserGesture_h