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.
25 #include <dali/public-api/common/dali-common.h>
26 #include <dali/public-api/object/property-types.h>
27 #include <dali/public-api/object/property-value.h>
28 #include <dali/public-api/object/ref-object.h>
29 #include <dali/public-api/signals/functor-delegate.h>
31 namespace Dali DALI_IMPORT_API
35 class ConnectionTrackerInterface;
38 * @brief Dali::BaseHandle is a handle to an internal Dali resource.
40 * Each Dali handle consists of a single private pointer, and a set of non-virtual forwarding functions.
41 * This hides the internal implementation, so it may be modified without affecting the public interface.
43 * Dali handles have implicit smart-pointer semantics.
44 * This avoids the need to match resource allocation methods like new/delete (the RAII idiom).
46 * Dali handles can be copied by value.
47 * When a Dali handle is copied, both the copy and original will point to the same Dali resource.
49 * The internal Dali resources are reference counted. copying a Dali handle will increase the reference count.
50 * A resource will not be deleted until all its Dali::BaseHandle handles are destroyed, or reset.
58 * @brief Used for null pointer assignment below
66 * @brief This constructor is used by Dali New() methods.
68 * @param [in] handle A pointer to a newly allocated Dali resource
70 BaseHandle(Dali::BaseObject* handle);
73 * @brief This constructor provides an uninitialized Dali::BaseHandle.
75 * This should be initialized with a Dali New() method before use.
76 * Methods called on an uninitialized Dali::BaseHandle will assert.
78 * BaseHandle handle; // uninitialized
79 * handle.SomeMethod(); // unsafe! This will assert
81 * handle = SomeClass::New(); // now initialized
82 * handle.SomeMethod(); // safe
88 * @brief Dali::BaseHandle is intended as a base class
90 * This is non-virtual since derived BaseHandle types must not contain data.
95 * @brief This copy constructor is required for (smart) pointer semantics.
97 * @param [in] handle A reference to the copied handle
99 BaseHandle(const BaseHandle& handle);
102 * @brief This assignment operator is required for (smart) pointer semantics.
104 * It makes this handle use the same BaseObject as the copied handle
105 * @param [in] rhs A reference to the copied handle
106 * @return A reference to this handle
108 BaseHandle& operator=(const BaseHandle& rhs);
111 * @brief This method is defined to allow assignment of the NULL value,
112 * and will throw an exception if passed any other value.
114 * Assigning to NULL is an alias for Reset().
115 * @param [in] rhs A NULL pointer
116 * @return A reference to this handle
118 BaseHandle& operator=(NullType* rhs);
121 * @brief Connects a void() functor to a specified signal.
123 * @pre The signal must be available in this object.
124 * @param [in] connectionTracker A connection tracker which can be used to disconnect.
125 * @param [in] signalName Name of the signal to connect to.
126 * @param [in] functor The functor to copy.
127 * @return True if the signal was available.
130 bool ConnectSignal( ConnectionTrackerInterface* connectionTracker, const std::string& signalName, const T& functor )
132 return DoConnectSignal( connectionTracker, signalName, FunctorDelegate::New( functor ) );
136 * @brief Perform action on this object with the given action name and attributes.
138 * @param [in] actionName The command for the action.
139 * @param [in] attributes The list of attributes for the action.
140 * @return The action is performed by the object or not.
142 bool DoAction(const std::string& actionName, const std::vector<Property::Value>& attributes);
145 * @brief Returns the type name for the Handle.
147 * Will return an empty string if the typename does not exist. This will happen for types that
148 * have not registered with type-registry.
150 * @return The type name. Empty string if the typename does not exist.
152 const std::string& GetTypeName() const;
156 // BaseHandle accessors
159 * @brief Retrieve the internal Dali resource.
161 * This is useful for checking the reference count of the internal resource.
162 * This method will assert, if the Dali::BaseHandle has not been initialized.
163 * @return The BaseObject which is referenced by the BaseHandle.
165 BaseObject& GetBaseObject();
168 * @brief Retrieve the internal Dali resource.
170 * This is useful for checking the reference count of the internal resource.
171 * This method will assert, if the Dali::BaseHandle has not been initialized.
172 * @return The BaseObject which is referenced by the BaseHandle.
174 const BaseObject& GetBaseObject() const;
177 * @brief Resets the handle.
179 * If no other handle copies exist, the internal Dali resouce will be deleted.
180 * Calling this is not required i.e. it will happen automatically when a Dali::BaseHandle is destroyed.
184 // BaseHandle comparisons - This is a variation of the safe bool idiom
187 * @brief Pointer-to-member type.
188 * Objects can be implicitly converted to this for validity checks.
190 typedef void (BaseHandle::*BooleanType)() const;
193 * @brief Converts an handle to a BooleanType.
195 * This is useful for checking whether the handle is empty.
197 operator BooleanType() const;
200 * @brief Equality operator overload.
202 * @param [in] rhs A reference to the compared handle.
203 * @return true if the handle handles point to the same Dali resource, or if both are NULL.
205 bool operator==(const BaseHandle& rhs) const;
208 * @brief Inequality operator overload.
210 * @param [in] rhs A reference to the compared handle.
211 * @return true if the handle handles point to the different Dali resources.
213 bool operator!=(const BaseHandle& rhs) const;
216 * @brief Get the reference counted object pointer.
218 * @return A pointer to the reference counted object.
220 Dali::RefObject* GetObjectPtr() const;
225 * @brief Not intended for application developers.
227 * @param [in] connectionTracker A connection tracker which can be used to disconnect.
228 * @param [in] signalName Name of the signal to connect to.
229 * @param [in] functorDelegate A newly allocatated functor delegate (takes ownership).
230 * @return True if the signal was available.
232 bool DoConnectSignal( ConnectionTrackerInterface* connectionTracker, const std::string& signalName, FunctorDelegate* functorDelegate );
235 * @brief Used by the safe bool idiom.
238 void ThisIsSaferThanReturningVoidStar() const {}
242 IntrusivePtr<Dali::RefObject> mObjectHandle; ///< Object this handle points at.
246 * @brief Template wrapper to downcast an base object handle to derived class handle.
248 * @pre The BaseHandle has been initialized.
249 * @param handle to a base object
250 * @return handle pointer to either a valid deriving handle or an uninitialized handle
253 T DownCast( BaseHandle handle )
255 return T::DownCast( handle );
258 // See also BaseHandle::BooleanType() conversion
261 * @brief Equality operator
263 template <typename T>
264 bool operator==(const BaseHandle& lhs, const T& rhs)
266 // We depart from the safe bool idiom to allow Dali::BaseHandle derived classes to be compared
267 return lhs == static_cast<const BaseHandle&>(rhs);
271 * @brief Equality operator
273 template <typename T>
274 bool operator!=(const BaseHandle& lhs, const T& rhs)
276 // We depart from the safe bool idiom to allow Dali::BaseHandle derived classes to be compared
277 return lhs != static_cast<const BaseHandle&>(rhs);
283 * @brief Less than operator
285 bool operator<(const BaseHandle& lhs, const BaseHandle& rhs);
289 #endif // __DALI_BASE_HANDLE_H__