1 /*
2  * Copyright (c) 2024 Huawei Device Co., Ltd.
3  * Licensed under the Apache License, Version 2.0 (the "License");
4  * you may not use this file except in compliance with the License.
5  * You may obtain a copy of the License at
6  *
7  *     http://www.apache.org/licenses/LICENSE-2.0
8  *
9  * Unless required by applicable law or agreed to in writing, software
10  * distributed under the License is distributed on an "AS IS" BASIS,
11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12  * See the License for the specific language governing permissions and
13  * limitations under the License.
14  */
15 
16 #ifndef META_API_PROPERTY_BINDING_H
17 #define META_API_PROPERTY_BINDING_H
18 
19 #include <meta/api/function.h>
20 #include <meta/base/interface_macros.h>
21 #include <meta/base/interface_traits.h>
22 #include <meta/interface/property/property.h>
23 
META_BEGIN_NAMESPACE()24 META_BEGIN_NAMESPACE()
25 
26 /**
27  * @brief The Binding class is a helper class for creating inline bindings for META_NS::Object properties.
28  */
29 class Binding {
30 public:
31     META_NO_COPY(Binding)
32     META_DEFAULT_MOVE(Binding)
33 
34     Binding() noexcept = default;
35     virtual ~Binding() = default;
36 
37     explicit Binding(const IProperty::ConstPtr& source) noexcept : source_(source) {}
38     explicit Binding(const IFunction::ConstPtr& binding) noexcept : binding_(binding) {}
39 
40     /**
41      * @brief Called by the framework to initialize the binding.
42      */
43     virtual bool MakeBind(const IProperty::Ptr& target)
44     {
45         PropertyLock p(target);
46         if (target) {
47             if (binding_) {
48                 return p->SetBind(binding_);
49             }
50             if (const auto source = source_.lock()) {
51                 return p->SetBind(source);
52             }
53             // Reset bind
54             p->ResetBind();
55             return true;
56         }
57         CORE_LOG_E("Cannot create binding: Invalid bind target");
58         return false;
59     }
60 
61 protected:
62     IProperty::ConstWeakPtr source_;
63     IFunction::ConstPtr binding_;
64 };
65 
66 /**
67  * @brief The TypedBinding class is a helper for creating typed binding objects. Usually it is enough
68  *        to use the Binding class, TypedBinding is mostly helpful for cleaner syntax when defining
69  *        bindings with a lambda function.
70  */
71 template<class Type>
72 class TypedBinding : public Binding {
73 public:
74     using PropertyType = Property<BASE_NS::remove_const_t<Type>>;
75 
76     META_NO_COPY_MOVE(TypedBinding)
77 
78     ~TypedBinding() override = default;
79     TypedBinding() noexcept = default;
80 
TypedBinding(const Property<const Type> & source)81     explicit TypedBinding(const Property<const Type>& source) noexcept : Binding(source) {}
TypedBinding(const PropertyType & source)82     explicit TypedBinding(const PropertyType& source) noexcept : Binding(source) {}
83 
84     template<class Callback, typename = EnableIfBindFunction<Callback>>
TypedBinding(Callback && callback)85     explicit TypedBinding(Callback&& callback) : Binding(META_NS::CreateBindFunction(BASE_NS::move(callback)))
86     {}
87 };
88 
89 META_END_NAMESPACE()
90 
91 #endif
92