jam@chromium.org | 533df72 | 2012-02-16 07:07:34 +0900 | [diff] [blame] | 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 | #ifndef BASE_SUPPORTS_USER_DATA_H_ |
| 6 | #define BASE_SUPPORTS_USER_DATA_H_ |
| 7 | |
| 8 | #include <map> |
| 9 | |
| 10 | #include "base/base_export.h" |
| 11 | #include "base/memory/linked_ptr.h" |
jam@chromium.org | 5c8ca51 | 2012-02-21 12:57:42 +0900 | [diff] [blame] | 12 | #include "base/memory/ref_counted.h" |
joth@chromium.org | db2811b | 2012-09-11 04:18:53 +0900 | [diff] [blame] | 13 | #include "base/threading/thread_checker.h" |
jam@chromium.org | 533df72 | 2012-02-16 07:07:34 +0900 | [diff] [blame] | 14 | |
| 15 | namespace base { |
| 16 | |
| 17 | // This is a helper for classes that want to allow users to stash random data by |
| 18 | // key. At destruction all the objects will be destructed. |
| 19 | class BASE_EXPORT SupportsUserData { |
| 20 | public: |
| 21 | SupportsUserData(); |
jam@chromium.org | 533df72 | 2012-02-16 07:07:34 +0900 | [diff] [blame] | 22 | |
| 23 | // Derive from this class and add your own data members to associate extra |
avi@chromium.org | 09840d3 | 2012-08-21 07:58:21 +0900 | [diff] [blame] | 24 | // information with this object. Alternatively, add this as a public base |
| 25 | // class to any class with a virtual destructor. |
jam@chromium.org | 533df72 | 2012-02-16 07:07:34 +0900 | [diff] [blame] | 26 | class BASE_EXPORT Data { |
| 27 | public: |
| 28 | virtual ~Data() {} |
| 29 | }; |
| 30 | |
| 31 | // The user data allows the clients to associate data with this object. |
| 32 | // Multiple user data values can be stored under different keys. |
| 33 | // This object will TAKE OWNERSHIP of the given data pointer, and will |
| 34 | // delete the object if it is changed or the object is destroyed. |
| 35 | Data* GetUserData(const void* key) const; |
| 36 | void SetUserData(const void* key, Data* data); |
avi@chromium.org | b2d507b | 2012-08-12 11:25:13 +0900 | [diff] [blame] | 37 | void RemoveUserData(const void* key); |
jam@chromium.org | 533df72 | 2012-02-16 07:07:34 +0900 | [diff] [blame] | 38 | |
joth@chromium.org | db2811b | 2012-09-11 04:18:53 +0900 | [diff] [blame] | 39 | // SupportsUserData is not thread-safe, and on debug build will assert it is |
| 40 | // only used on one thread. Calling this method allows the caller to hand |
| 41 | // the SupportsUserData instance across threads. Use only if you are taking |
| 42 | // full control of the synchronization of that hand over. |
| 43 | void DetachUserDataThread(); |
| 44 | |
rsleevi@chromium.org | d55e9a4 | 2012-06-26 15:23:00 +0900 | [diff] [blame] | 45 | protected: |
| 46 | virtual ~SupportsUserData(); |
| 47 | |
jam@chromium.org | 533df72 | 2012-02-16 07:07:34 +0900 | [diff] [blame] | 48 | private: |
| 49 | typedef std::map<const void*, linked_ptr<Data> > DataMap; |
| 50 | |
avi@chromium.org | 09840d3 | 2012-08-21 07:58:21 +0900 | [diff] [blame] | 51 | // Externally-defined data accessible by key. |
jam@chromium.org | 533df72 | 2012-02-16 07:07:34 +0900 | [diff] [blame] | 52 | DataMap user_data_; |
joth@chromium.org | db2811b | 2012-09-11 04:18:53 +0900 | [diff] [blame] | 53 | // Guards usage of |user_data_| |
| 54 | ThreadChecker thread_checker_; |
jam@chromium.org | 533df72 | 2012-02-16 07:07:34 +0900 | [diff] [blame] | 55 | |
| 56 | DISALLOW_COPY_AND_ASSIGN(SupportsUserData); |
| 57 | }; |
| 58 | |
jam@chromium.org | 5c8ca51 | 2012-02-21 12:57:42 +0900 | [diff] [blame] | 59 | // Adapter class that releases a refcounted object when the |
| 60 | // SupportsUserData::Data object is deleted. |
| 61 | template <typename T> |
| 62 | class UserDataAdapter : public base::SupportsUserData::Data { |
| 63 | public: |
grunell@chromium.org | 8781fe4 | 2013-10-04 03:44:06 +0900 | [diff] [blame] | 64 | static T* Get(SupportsUserData* supports_user_data, const void* key) { |
avi@chromium.org | 9592b54 | 2012-10-09 06:08:54 +0900 | [diff] [blame] | 65 | UserDataAdapter* data = |
jam@chromium.org | 5c8ca51 | 2012-02-21 12:57:42 +0900 | [diff] [blame] | 66 | static_cast<UserDataAdapter*>(supports_user_data->GetUserData(key)); |
avi@chromium.org | 9592b54 | 2012-10-09 06:08:54 +0900 | [diff] [blame] | 67 | return data ? static_cast<T*>(data->object_.get()) : NULL; |
jam@chromium.org | 5c8ca51 | 2012-02-21 12:57:42 +0900 | [diff] [blame] | 68 | } |
| 69 | |
| 70 | UserDataAdapter(T* object) : object_(object) {} |
jam@chromium.org | 14eaa3f | 2012-02-25 08:38:12 +0900 | [diff] [blame] | 71 | T* release() { return object_.release(); } |
jam@chromium.org | 5c8ca51 | 2012-02-21 12:57:42 +0900 | [diff] [blame] | 72 | |
| 73 | private: |
| 74 | scoped_refptr<T> object_; |
| 75 | |
| 76 | DISALLOW_COPY_AND_ASSIGN(UserDataAdapter); |
| 77 | }; |
| 78 | |
jam@chromium.org | 533df72 | 2012-02-16 07:07:34 +0900 | [diff] [blame] | 79 | } // namespace base |
| 80 | |
| 81 | #endif // BASE_SUPPORTS_USER_DATA_H_ |