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/******************************************************************************
*
* Copyright 2020 Google, Inc.
*
* 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 <mutex>
#include <string>
#include <thread>
#include <unordered_set>
#include "raw_address.h"
#include "lru.h"
namespace bluetooth {
namespace common {
class MetricIdAllocator {
public:
using Callback = std::function<bool(const RawAddress& address, const int id)>;
static const size_t kMaxNumUnpairedDevicesInMemory;
static const size_t kMaxNumPairedDevicesInMemory;
static const int kMinId;
static const int kMaxId;
~MetricIdAllocator();
/**
* Get the instance of singleton
*
* @return MetricIdAllocator&
*/
static MetricIdAllocator& GetInstance();
/**
* Initialize the allocator
*
* @param paired_device_map map from mac_address to id already saved
* in the disk before init
* @param save_id_callback a callback that will be called after successfully
* saving id for a paired device
* @param forget_device_callback a callback that will be called after
* successful id deletion for forgotten device,
* @return true if successfully initialized
*/
bool Init(const std::unordered_map<RawAddress, int>& paired_device_map,
Callback save_id_callback, Callback forget_device_callback);
/**
* Close the allocator. should be called when Bluetooth process is killed
*
* @return true if successfully close
*/
bool Close();
/**
* Check if no id saved in memory
*
* @return true if no id is saved
*/
bool IsEmpty() const;
/**
* Allocate an id for a scanned device, or return the id if there is already
* one
*
* @param mac_address mac address of Bluetooth device
* @return the id of device
*/
int AllocateId(const RawAddress& mac_address);
/**
* Save the id for a paired device
*
* @param mac_address mac address of Bluetooth device
* @return true if save successfully
*/
bool SaveDevice(const RawAddress& mac_address);
/**
* Delete the id for a device to be forgotten
*
* @param mac_address mac address of Bluetooth device
*/
void ForgetDevice(const RawAddress& mac_address);
/**
* Check if an id is valid.
* The id should be less than or equal to kMaxId and bigger than or equal to
* kMinId
*
* @param mac_address mac address of Bluetooth device
* @return true if delete successfully
*/
static bool IsValidId(const int id);
protected:
// Singleton
MetricIdAllocator();
private:
static const std::string LOGGING_TAG;
mutable std::mutex id_allocator_mutex_;
LegacyLruCache<RawAddress, int> paired_device_cache_;
LegacyLruCache<RawAddress, int> temporary_device_cache_;
std::unordered_set<int> id_set_;
int next_id_{kMinId};
bool initialized_{false};
Callback save_id_callback_;
Callback forget_device_callback_;
void ForgetDevicePostprocess(const RawAddress& mac_address, const int id);
// delete copy constructor for singleton
MetricIdAllocator(MetricIdAllocator const&) = delete;
MetricIdAllocator& operator=(MetricIdAllocator const&) = delete;
};
} // namespace common
} // namespace bluetooth