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_INTERFACE_IEVENT_H
17 #define META_INTERFACE_IEVENT_H
18
19 #include <base/containers/array_view.h>
20 #include <base/containers/string_view.h>
21 #include <base/util/uid.h>
22 #include <core/plugin/intf_interface.h>
23
24 #include <meta/base/interface_macros.h>
25 #include <meta/base/namespace.h>
26 #include <meta/interface/intf_callable.h>
27
28 META_BEGIN_NAMESPACE()
29
30 META_REGISTER_INTERFACE(IEvent, "8b3c8322-54d6-4d1c-943c-207190576a4e")
31
32 class IEvent : public CORE_NS::IInterface {
33 META_INTERFACE(CORE_NS::IInterface, IEvent);
34
35 public:
36 /** handler identifier, at least big enough to keep an object pointer. */
37 using Token = uint64_t;
38
39 /** Returns the interface id that the callables must implement. */
40 virtual BASE_NS::Uid GetCallableUid() const = 0;
41 /** Returns the name of this event. Same as GetEventTypeName if not explicitly set. */
42 virtual BASE_NS::string_view GetName() const = 0;
43 /** Returns the event type name. */
44 virtual BASE_NS::string_view GetEventTypeName() const = 0;
45
46 /**
47 * @brief Add handler which is invoked when event is triggered
48 * @param userToken Optional token that is used to identify the handler.
49 * Notice that this should be unique or it can collide with other handler tokens.
50 * @return Default constructed Token if "invalid bindable", token already in use or other error.
51 */
52 virtual Token AddHandler(const ICallable::Ptr&, Token userToken) = 0;
AddHandler(const ICallable::Ptr & p)53 Token AddHandler(const ICallable::Ptr& p)
54 {
55 return AddHandler(p, {});
56 }
57
58 /**
59 * @brief Remove handler with given token (Token returned by AddHandler previously).
60 */
61 virtual bool RemoveHandler(Token) = 0;
62
63 /**
64 * @brief Remove all handlers
65 */
66 virtual void Reset() = 0;
67
68 /**
69 * @brief Check if callable can be added as handler.
70 */
71 virtual bool IsCompatibleWith(const ICallable::Ptr&) const = 0;
72
73 /**
74 * @brief Get list of current handlers.
75 */
76 virtual BASE_NS::vector<ICallable::ConstPtr> GetHandlers() const = 0;
77
78 /**
79 * @brief Returns true if the event has any handlers, false otherwise.
80 */
81 virtual bool HasHandlers() const = 0;
82 };
83
84 template<typename EventType, typename Ret, typename... Args>
85 class IEventCallable : public ICallable {
86 META_INTERFACE(ICallable, IEventCallable, EventType::UID)
87 public:
88 using ReturnType = Ret;
89 using InterfaceType = IEventCallable<EventType, Ret, Args...>;
90 using InterfaceTypePtr = typename InterfaceType::Ptr;
91 using FunctionType = Ret(Args...);
92 virtual Ret Invoke(Args...) = 0;
93 };
94
95 template<typename MyEvent, typename... Args>
Invoke(const IEvent::Ptr & event,Args &&...args)96 inline auto Invoke(const IEvent::Ptr& event, Args&&... args)
97 {
98 if (auto i = interface_cast<typename MyEvent::InterfaceType>(event)) {
99 return i->Invoke(BASE_NS::forward<Args>(args)...);
100 }
101 CORE_LOG_W("Trying to Invoke wrong type of event");
102 if constexpr (!BASE_NS::is_same_v<typename MyEvent::ReturnType, void>) {
103 return typename MyEvent::ReturnType {};
104 }
105 }
106
107 META_END_NAMESPACE()
108
109 #endif
110