content/public/browser/notification_details.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 // This file defines the type used to provide details for NotificationService
   6 // notifications.
   7
   8 #ifndef CONTENT_PUBLIC_BROWSER_NOTIFICATION_DETAILS_H_
   9 #define CONTENT_PUBLIC_BROWSER_NOTIFICATION_DETAILS_H_
  10
  11 #include "base/basictypes.h"
  12 #include "content/common/content_export.h"
  13
  14 namespace content {
  15
  16 // Do not declare a NotificationDetails directly--use either
  17 // "Details<detailsclassname>(detailsclasspointer)" or
  18 // NotificationService::NoDetails().
  19 class CONTENT_EXPORT NotificationDetails {
  20  public:
  21   NotificationDetails() : ptr_(NULL) {}
  22   NotificationDetails(const NotificationDetails& other) : ptr_(other.ptr_) {}
  23   ~NotificationDetails() {}
  24
  25   // NotificationDetails can be used as the index for a map; this method
  26   // returns the pointer to the current details as an identifier, for use as a
  27   // map index.
  28   uintptr_t map_key() const { return reinterpret_cast<uintptr_t>(ptr_); }
  29
  30   bool operator!=(const NotificationDetails& other) const {
  31     return ptr_ != other.ptr_;
  32   }
  33
  34   bool operator==(const NotificationDetails& other) const {
  35     return ptr_ == other.ptr_;
  36   }
  37
  38  protected:
  39    explicit NotificationDetails(const void* ptr) : ptr_(ptr) {}
  40
  41   // Declaring this const allows Details<T> to be used with both T = Foo and
  42   // T = const Foo.
  43   const void* ptr_;
  44 };
  45
  46 template <class T>
  47 class Details : public NotificationDetails {
  48  public:
  49   // TODO(erg): Our code hard relies on implicit conversion
  50   Details(T* ptr) : NotificationDetails(ptr) {}  // NOLINT
  51   Details(const NotificationDetails& other)      // NOLINT
  52     : NotificationDetails(other) {}
  53
  54   T* operator->() const { return ptr(); }
  55   // The casts here allow this to compile with both T = Foo and T = const Foo.
  56   T* ptr() const { return static_cast<T*>(const_cast<void*>(ptr_)); }
  57 };
  58
  59 }  // namespace content
  60
  61 #endif  // CONTENT_PUBLIC_BROWSER_NOTIFICATION_DETAILS_H_