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 #ifndef META_SRC_CONTAINER_OBSERVER_H
16 #define META_SRC_CONTAINER_OBSERVER_H
17 
18 #include <base/containers/unordered_map.h>
19 
20 #include <meta/ext/event_impl.h>
21 #include <meta/interface/builtin_objects.h>
22 #include <meta/interface/intf_container_observer.h>
23 
24 #include "object.h"
25 
26 META_BEGIN_NAMESPACE()
27 
28 class ContainerChangeListener final {
29 public:
30     META_NO_COPY(ContainerChangeListener)
31     ~ContainerChangeListener();
32     ContainerChangeListener() = delete;
33     ContainerChangeListener(ContainerChangeListener&& other);
34     ContainerChangeListener& operator=(ContainerChangeListener&& other);
35 
36     explicit ContainerChangeListener(const IContainer::Ptr& container);
37     // Note the copy assignment implementation which is not directly applicable to all use cases
38     bool operator==(const ContainerChangeListener& other) const noexcept;
39     bool Subscribe(const IOnChildChanged::InterfaceTypePtr& onAdded, const IOnChildChanged::InterfaceTypePtr& onRemoved,
40         const IOnChildMoved::InterfaceTypePtr& onMoved);
41     void Unsubscribe();
42 
43 private:
44     mutable BASE_NS::pair<IEvent::Token, IOnChildChanged::InterfaceTypePtr> added_;
45     mutable BASE_NS::pair<IEvent::Token, IOnChildChanged::InterfaceTypePtr> removed_;
46     mutable BASE_NS::pair<IEvent::Token, IOnChildMoved::InterfaceTypePtr> moved_;
47     mutable IContainer::WeakPtr container_;
48 };
49 
50 class ContainerObserver
51     : public Internal::MetaObjectFwd<ContainerObserver, ClassId::ContainerObserver, IContainerObserver> {
52     using Super = Internal::MetaObjectFwd<ContainerObserver, ClassId::ContainerObserver, IContainerObserver>;
53     using Super::Super;
54 
55 protected: // LifeCycle
56     bool Build(const IMetadata::Ptr&) override;
57 
58 protected: // IContainerObjserver
59     void SetContainer(const IContainer::Ptr& container) override;
60 
61     META_IMPLEMENT_INTERFACE_EVENT(IContainerObserver, IOnChildChanged, OnDescendantAdded)
62     META_IMPLEMENT_INTERFACE_EVENT(IContainerObserver, IOnChildChanged, OnDescendantRemoved)
63     META_IMPLEMENT_INTERFACE_EVENT(IContainerObserver, IOnChildMoved, OnDescendantMoved)
64 
65 private:
66     void Subscribe(const IContainer::Ptr& base);
67     void Unsubscribe(const IContainer::Ptr& base);
68     void InvokeAdded(const ChildChangedInfo& info);
69     void InvokeRemoved(const ChildChangedInfo& info);
70     void InvokeMoved(const ChildMovedInfo& info);
71     IContainer::Ptr container_;
72     IOnChildChanged::InterfaceTypePtr addedCallable_;
73     IOnChildChanged::InterfaceTypePtr removedCallable_;
74     IOnChildMoved::InterfaceTypePtr movedCallable_;
75 
76     struct Subscription {
SubscriptionContainerObserver::Subscription77         Subscription(IContainer::WeakPtr container, ContainerChangeListener&& listener)
78             : container(BASE_NS::move(container)), listener(BASE_NS::move(listener))
79         {}
80         IContainer::WeakPtr container;
81         ContainerChangeListener listener;
82     };
83 
84     BASE_NS::vector<Subscription> subscriptions_;
85 };
86 
87 META_END_NAMESPACE()
88 
89 #endif // META_SRC_CONTAINER_OBSERVER_H
90