ios/public/consumer/base/supports_user_data.h

   1 // Copyright 2013 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 #ifndef IOS_PUBLIC_CONSUMER_BASE_SUPPORTS_USER_DATA_H_
   6 #define IOS_PUBLIC_CONSUMER_BASE_SUPPORTS_USER_DATA_H_
   7
   8 namespace ios {
   9
  10 class SupportsUserDataInternal;
  11
  12 // This is a helper for classes that want to allow users to stash random data by
  13 // key. At destruction all the objects will be destructed.
  14 class SupportsUserData {
  15  public:
  16   SupportsUserData();
  17
  18   // Derive from this class and add your own data members to associate extra
  19   // information with this object. Alternatively, add this as a public base
  20   // class to any class with a virtual destructor.
  21   class Data {
  22    public:
  23     virtual ~Data() {}
  24   };
  25
  26   // The user data allows the clients to associate data with this object.
  27   // Multiple user data values can be stored under different keys.
  28   // This object will TAKE OWNERSHIP of the given data pointer, and will
  29   // delete the object if it is changed or the object is destroyed.
  30   Data* GetUserData(const void* key) const;
  31   void SetUserData(const void* key, Data* data);
  32   void RemoveUserData(const void* key);
  33
  34   // SupportsUserData is not thread-safe, and on debug build will assert it is
  35   // only used on one thread. Calling this method allows the caller to hand
  36   // the SupportsUserData instance across threads. Use only if you are taking
  37   // full control of the synchronization of that handover.
  38   void DetachUserDataThread();
  39
  40  protected:
  41   virtual ~SupportsUserData();
  42
  43  private:
  44   // Owned by this object and scoped to its lifetime.
  45   SupportsUserDataInternal* internal_helper_;
  46 };
  47
  48 }  // namespace ios
  49
  50 #endif  // IOS_PUBLIC_CONSUMER_BASE_SUPPORTS_USER_DATA_H_