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Diffstat (limited to 'base/property_bag.h')
-rw-r--r-- | base/property_bag.h | 179 |
1 files changed, 0 insertions, 179 deletions
diff --git a/base/property_bag.h b/base/property_bag.h deleted file mode 100644 index 16c20fa..0000000 --- a/base/property_bag.h +++ /dev/null @@ -1,179 +0,0 @@ -// Copyright (c) 2011 The Chromium Authors. All rights reserved. -// Use of this source code is governed by a BSD-style license that can be -// found in the LICENSE file. - -#ifndef BASE_PROPERTY_BAG_H_ -#define BASE_PROPERTY_BAG_H_ - -#include <map> - -#include "base/basictypes.h" -#include "base/base_export.h" - -template <typename T> class linked_ptr; - -namespace base { - -class PropertyAccessorBase; - -// A property bag holds a generalized list of arbitrary metadata called -// properties. Each property is a class type derived from PropertyBag::Prop -// that can be set and retrieved. -// -// The property bag is not read or written directly. Instead, callers go -// through a PropertyAccessor. The Accessor generates the unique IDs that -// identify different properties. The Accessor is templatized to also provide -// typesafety to the callers. -// -// Example: -// // Note: you don't want to use Singleton for your Accessor if you're using -// // a simple type like int or string as the data, since it will enforce that -// // there is only one singleton for that type, which will conflict. If -// // you're putting in some struct that's unique to you, go ahead. -// PropertyAccessor<int>* my_accessor() const { -// static PropertyAccessor<int>* accessor = NULL; -// if (!accessor) accessor = new PropertyAccessor<int>; -// return accessor; -// } -// -// void doit(SomeObjectThatImplementsPropertyBag* object) { -// PropertyAccessor<int>* accessor = my_accessor(); -// int* property = accessor->GetProperty(object); -// if (property) -// ... use property ... -// -// accessor->SetProperty(object, 22); -// } -class BASE_EXPORT PropertyBag { - public: - // The type that uniquely identifies a property type. - typedef int PropID; - enum { NULL_PROP_ID = -1 }; // Invalid property ID. - - // Properties are all derived from this class. They must be deletable and - // copyable - class Prop { - public: - virtual ~Prop() {} - - // Copies the property and returns a pointer to the new one. The caller is - // responsible for managing the lifetime. - virtual Prop* copy() = 0; - }; - - PropertyBag(); - PropertyBag(const PropertyBag& other); - virtual ~PropertyBag(); - - PropertyBag& operator=(const PropertyBag& other); - - private: - friend class PropertyAccessorBase; - - typedef std::map<PropID, linked_ptr<Prop> > PropertyMap; - - // Used by the PropertyAccessor to set the property with the given ID. - // Ownership of the given pointer will be transferred to us. Any existing - // property matching the given ID will be deleted. - void SetProperty(PropID id, Prop* prop); - - // Used by the PropertyAccessor to retrieve the property with the given ID. - // The returned pointer will be NULL if there is no match. Ownership of the - // pointer will stay with the property bag. - Prop* GetProperty(PropID id); - const Prop* GetProperty(PropID id) const; - - // Deletes the property with the given ID from the bag if it exists. - void DeleteProperty(PropID id); - - PropertyMap props_; - - // Copy and assign is explicitly allowed for this class. -}; - -// PropertyAccessorBase ------------------------------------------------------- - -// Manages getting the unique IDs to identify a property. Callers should use -// PropertyAccessor below instead. -class BASE_EXPORT PropertyAccessorBase { - public: - PropertyAccessorBase(); - virtual ~PropertyAccessorBase() {} - - // Removes our property, if any, from the given property bag. - void DeleteProperty(PropertyBag* bag) { - bag->DeleteProperty(prop_id_); - } - - protected: - void SetPropertyInternal(PropertyBag* bag, PropertyBag::Prop* prop) { - bag->SetProperty(prop_id_, prop); - } - PropertyBag::Prop* GetPropertyInternal(PropertyBag* bag) { - return bag->GetProperty(prop_id_); - } - const PropertyBag::Prop* GetPropertyInternal(const PropertyBag* bag) const { - return bag->GetProperty(prop_id_); - } - - private: - // Identifier for this property. - PropertyBag::PropID prop_id_; - - DISALLOW_COPY_AND_ASSIGN(PropertyAccessorBase); -}; - -// PropertyAccessor ----------------------------------------------------------- - -// Provides typesafe accessor functions for a property bag, and manages the -// unique identifiers for properties via the PropertyAccessorBase. -template<class T> -class PropertyAccessor : public PropertyAccessorBase { - public: - PropertyAccessor() : PropertyAccessorBase() {} - virtual ~PropertyAccessor() {} - - // Makes a copy of the |prop| object for storage. - void SetProperty(PropertyBag* bag, const T& prop) { - SetPropertyInternal(bag, new Container(prop)); - } - - // Returns our property in the given bag or NULL if there is no match. The - // returned pointer's ownership will stay with the property bag. - T* GetProperty(PropertyBag* bag) { - PropertyBag::Prop* prop = GetPropertyInternal(bag); - if (!prop) - return NULL; - return static_cast<Container*>(prop)->get(); - } - const T* GetProperty(const PropertyBag* bag) const { - const PropertyBag::Prop* prop = GetPropertyInternal(bag); - if (!prop) - return NULL; - return static_cast<const Container*>(prop)->get(); - } - - // See also DeleteProperty on thn PropertyAccessorBase. - - private: - class Container : public PropertyBag::Prop { - public: - explicit Container(const T& data) : data_(data) {} - - T* get() { return &data_; } - const T* get() const { return &data_; } - - private: - virtual Prop* copy() { - return new Container(data_); - } - - T data_; - }; - - DISALLOW_COPY_AND_ASSIGN(PropertyAccessor); -}; - -} // namespace base - -#endif // BASE_PROPERTY_BAG_H_ |