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/*
* Copyright 2019 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#pragma once
#include <array>
#include "common/bind.h"
#include "common/callback.h"
#include "os/log.h"
namespace bluetooth {
namespace common {
// Tracks an observer registration on client (observer) code. Register() returns a wrapped callback object which can
// be passed to server's register API. Unregister() invalidates the wrapped callback so all callbacks that are posted
// to the client handler after the client called Unregister() call and before the server processed the Unregister()
// call on its handler, are dropped.
// Note: Register() invalidates the previous registration.
class SingleObserverRegistry {
public:
template <typename R, typename... T>
decltype(auto) Register(Callback<R(T...)> callback) {
session_++;
return Bind(&SingleObserverRegistry::callback_wrapper<R, T...>, Unretained(this), session_, callback);
}
void Unregister() {
session_++;
}
private:
template <typename R, typename... T>
void callback_wrapper(int session, Callback<R(T...)> callback, T... t) {
if (session == session_) {
callback.Run(std::forward<T>(t)...);
}
}
uint8_t session_ = 0;
};
// Tracks observer registration for multiple event type. Each event type is represented as an integer in [0, Capacity).
template <int Capacity = 10>
class MultipleObserverRegistry {
public:
template <typename R, typename... T>
decltype(auto) Register(int event_type, Callback<R(T...)> callback) {
ASSERT(event_type < Capacity);
return registry_[event_type].Register(callback);
}
void Unregister(int event_type) {
ASSERT(event_type < Capacity);
registry_[event_type].Unregister();
}
std::array<SingleObserverRegistry, Capacity> registry_;
};
} // namespace common
} // namespace bluetooth
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