1 #ifndef __DALI_BASE_HANDLE_H__
2 #define __DALI_BASE_HANDLE_H__
5 * Copyright (c) 2014 Samsung Electronics Co., Ltd.
7 * Licensed under the Apache License, Version 2.0 (the "License");
8 * you may not use this file except in compliance with the License.
9 * You may obtain a copy of the License at
11 * http://www.apache.org/licenses/LICENSE-2.0
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS,
15 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
17 * limitations under the License.
22 * @addtogroup CAPI_DALI_OBJECT_MODULE
30 #include <dali/public-api/common/dali-common.h>
31 #include <dali/public-api/object/property-types.h>
32 #include <dali/public-api/object/property-value.h>
33 #include <dali/public-api/object/ref-object.h>
34 #include <dali/public-api/signals/functor-delegate.h>
36 namespace Dali DALI_IMPORT_API
40 class ConnectionTrackerInterface;
43 * @brief Dali::BaseHandle is a handle to an internal Dali resource.
45 * Each Dali handle consists of a single private pointer, and a set of non-virtual forwarding functions.
46 * This hides the internal implementation, so it may be modified without affecting the public interface.
48 * Dali handles have implicit smart-pointer semantics.
49 * This avoids the need to match resource allocation methods like new/delete (the RAII idiom).
51 * Dali handles can be copied by value.
52 * When a Dali handle is copied, both the copy and original will point to the same Dali resource.
54 * The internal Dali resources are reference counted. copying a Dali handle will increase the reference count.
55 * A resource will not be deleted until all its Dali::BaseHandle handles are destroyed, or reset.
63 * @brief Used for null pointer assignment below
71 * @brief This constructor is used by Dali New() methods.
73 * @param [in] handle A pointer to a newly allocated Dali resource
75 BaseHandle(Dali::BaseObject* handle);
78 * @brief This constructor provides an uninitialized Dali::BaseHandle.
80 * This should be initialized with a Dali New() method before use.
81 * Methods called on an uninitialized Dali::BaseHandle will assert.
83 * BaseHandle handle; // uninitialized
84 * handle.SomeMethod(); // unsafe! This will assert
86 * handle = SomeClass::New(); // now initialized
87 * handle.SomeMethod(); // safe
93 * @brief Dali::BaseHandle is intended as a base class.
95 virtual ~BaseHandle();
98 * @brief This copy constructor is required for (smart) pointer semantics.
100 * @param [in] handle A reference to the copied handle
102 BaseHandle(const BaseHandle& handle);
105 * @brief This assignment operator is required for (smart) pointer semantics.
107 * It makes this handle use the same BaseObject as the copied handle
108 * @param [in] rhs A reference to the copied handle
109 * @return A reference to this handle
111 BaseHandle& operator=(const BaseHandle& rhs);
114 * @brief This method is defined to allow assignment of the NULL value,
115 * and will throw an exception if passed any other value.
117 * Assigning to NULL is an alias for Reset().
118 * @param [in] rhs A NULL pointer
119 * @return A reference to this handle
121 BaseHandle& operator=(NullType* rhs);
124 * @brief Connects a void() functor to a specified signal.
126 * @pre The signal must be available in this object.
127 * @param [in] connectionTracker A connection tracker which can be used to disconnect.
128 * @param [in] signalName Name of the signal to connect to.
129 * @param [in] functor The functor to copy.
130 * @return True if the signal was available.
133 bool ConnectSignal( ConnectionTrackerInterface* connectionTracker, const std::string& signalName, const T& functor )
135 return DoConnectSignal( connectionTracker, signalName, FunctorDelegate::New( functor ) );
139 * @brief Perform action on this object with the given action name and attributes.
141 * @param [in] actionName The command for the action.
142 * @param [in] attributes The list of attributes for the action.
143 * @return The action is performed by the object or not.
145 bool DoAction(const std::string& actionName, const std::vector<Property::Value>& attributes);
148 * @brief Returns the type name for the Handle.
150 * Will return an empty string if the typename does not exist. This will happen for types that
151 * have not registered with type-registry.
153 * @return The type name. Empty string if the typename does not exist.
155 const std::string& GetTypeName() const;
159 // BaseHandle accessors
162 * @brief Retrieve the internal Dali resource.
164 * This is useful for checking the reference count of the internal resource.
165 * This method will assert, if the Dali::BaseHandle has not been initialized.
166 * @return The BaseObject which is referenced by the BaseHandle.
168 BaseObject& GetBaseObject();
171 * @brief Retrieve the internal Dali resource.
173 * This is useful for checking the reference count of the internal resource.
174 * This method will assert, if the Dali::BaseHandle has not been initialized.
175 * @return The BaseObject which is referenced by the BaseHandle.
177 const BaseObject& GetBaseObject() const;
180 * @brief Resets the handle.
182 * If no other handle copies exist, the internal Dali resouce will be deleted.
183 * Calling this is not required i.e. it will happen automatically when a Dali::BaseHandle is destroyed.
187 // BaseHandle comparisons - This is a variation of the safe bool idiom
190 * @brief Pointer-to-member type.
191 * Objects can be implicitly converted to this for validity checks.
193 typedef void (BaseHandle::*BooleanType)() const;
196 * @brief Converts an handle to a BooleanType.
198 * This is useful for checking whether the handle is empty.
200 operator BooleanType() const;
203 * @brief Equality operator overload.
205 * @param [in] rhs A reference to the compared handle.
206 * @return true if the handle handles point to the same Dali resource, or if both are NULL.
208 bool operator==(const BaseHandle& rhs) const;
211 * @brief Inequality operator overload.
213 * @param [in] rhs A reference to the compared handle.
214 * @return true if the handle handles point to the different Dali resources.
216 bool operator!=(const BaseHandle& rhs) const;
219 * @brief Get the reference counted object pointer.
221 * @return A pointer to the reference counted object.
223 Dali::RefObject* GetObjectPtr() const;
228 * @brief Not intended for application developers.
230 * @param [in] connectionTracker A connection tracker which can be used to disconnect.
231 * @param [in] signalName Name of the signal to connect to.
232 * @param [in] functorDelegate A newly allocatated functor delegate (takes ownership).
233 * @return True if the signal was available.
235 bool DoConnectSignal( ConnectionTrackerInterface* connectionTracker, const std::string& signalName, FunctorDelegate* functorDelegate );
238 * @brief Used by the safe bool idiom.
241 void ThisIsSaferThanReturningVoidStar() const {}
245 IntrusivePtr<Dali::RefObject> mObjectHandle; ///< Object this handle points at.
249 * @brief Template wrapper to downcast an base object handle to derived class handle.
251 * @pre The BaseHandle has been initialized.
252 * @param handle to a base object
253 * @return handle pointer to either a valid deriving handle or an uninitialized handle
256 T DownCast( BaseHandle handle )
258 return T::DownCast( handle );
261 // See also BaseHandle::BooleanType() conversion
264 * @brief Equality operator
266 template <typename T>
267 bool operator==(const BaseHandle& lhs, const T& rhs)
269 // We depart from the safe bool idiom to allow Dali::BaseHandle derived classes to be compared
270 return lhs == static_cast<const BaseHandle&>(rhs);
274 * @brief Equality operator
276 template <typename T>
277 bool operator!=(const BaseHandle& lhs, const T& rhs)
279 // We depart from the safe bool idiom to allow Dali::BaseHandle derived classes to be compared
280 return lhs != static_cast<const BaseHandle&>(rhs);
286 * @brief Less than operator
288 bool operator<(const BaseHandle& lhs, const BaseHandle& rhs);
295 #endif // __DALI_BASE_HANDLE_H__