third_party/WebKit/public/platform/WebCallbacks.h

   1 /*
   2  * Copyright (C) 2013 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:
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   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,
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  26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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  28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29  */
  30
  31 #ifndef WebCallbacks_h
  32 #define WebCallbacks_h
  33
  34 #include "public/platform/WebPassOwnPtr.h"
  35
  36 namespace blink {
  37
  38 // A WebCallbacks<S, T> represents a callback object. Typically it is created
  39 // in Blink and passed to Chromium, and onSuccess or onError will be called
  40 // from Chromium.
  41 // When transferring ownership, use |WebPrivatePassOwnPtr<X>| as a type
  42 // parameter. Otherwise, |const X&| or |X| for a type parameter. It is
  43 // generally not preferred to use |X*| because the object ownership is not well
  44 // specified.
  45
  46 template<typename S, typename T>
  47 class WebCallbacks {
  48 public:
  49     virtual ~WebCallbacks() {}
  50     virtual void onSuccess(S) {}
  51     virtual void onError(T) {}
  52 };
  53
  54 template<typename T>
  55 class WebCallbacks<void, T> {
  56 public:
  57     virtual ~WebCallbacks() {}
  58     virtual void onSuccess() {}
  59     virtual void onError(T) {}
  60 };
  61
  62 template<typename S>
  63 class WebCallbacks<S, void> {
  64 public:
  65     virtual ~WebCallbacks() {}
  66     virtual void onSuccess(S) {}
  67     virtual void onError() {}
  68 };
  69
  70 template<>
  71 class WebCallbacks<void, void> {
  72 public:
  73     virtual ~WebCallbacks() {}
  74     virtual void onSuccess() {}
  75     virtual void onError() {}
  76 };
  77
  78 } // namespace blink
  79
  80 #endif