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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.
*
******************************************************************************/
#include "metric_id_allocator.h"
#include <base/logging.h>
#include <functional>
#include <mutex>
#include <thread>
#include "types/raw_address.h"
namespace bluetooth {
namespace common {
const std::string MetricIdAllocator::LOGGING_TAG = "BluetoothMetricIdAllocator";
const size_t MetricIdAllocator::kMaxNumUnpairedDevicesInMemory = 200;
const size_t MetricIdAllocator::kMaxNumPairedDevicesInMemory = 65000;
const int MetricIdAllocator::kMinId = 1;
const int MetricIdAllocator::kMaxId = 65534; // 2^16 - 2
// id space should always be larger than kMaxNumPairedDevicesInMemory +
// kMaxNumUnpairedDevicesInMemory
static_assert((MetricIdAllocator::kMaxNumUnpairedDevicesInMemory +
MetricIdAllocator::kMaxNumPairedDevicesInMemory) <
(MetricIdAllocator::kMaxId - MetricIdAllocator::kMinId),
"id space should always be larger than "
"kMaxNumPairedDevicesInMemory + MaxNumUnpairedDevicesInMemory");
MetricIdAllocator::MetricIdAllocator()
: paired_device_cache_(kMaxNumPairedDevicesInMemory, LOGGING_TAG),
temporary_device_cache_(kMaxNumUnpairedDevicesInMemory, LOGGING_TAG) {}
bool MetricIdAllocator::Init(
const std::unordered_map<RawAddress, int>& paired_device_map,
Callback save_id_callback, Callback forget_device_callback) {
std::lock_guard<std::mutex> lock(id_allocator_mutex_);
if (initialized_) {
return false;
}
// init paired_devices_map
if (paired_device_map.size() > kMaxNumPairedDevicesInMemory) {
LOG(FATAL)
<< LOGGING_TAG
<< "Paired device map is bigger than kMaxNumPairedDevicesInMemory";
// fail loudly to let caller know
return false;
}
next_id_ = kMinId;
for (const auto& p : paired_device_map) {
if (p.second < kMinId || p.second > kMaxId) {
LOG(FATAL) << LOGGING_TAG << "Invalid Bluetooth Metric Id in config";
}
auto evicted = paired_device_cache_.Put(p.first, p.second);
if (evicted) {
ForgetDevicePostprocess(evicted->first, evicted->second);
}
id_set_.insert(p.second);
next_id_ = std::max(next_id_, p.second + 1);
}
if (next_id_ > kMaxId) {
next_id_ = kMinId;
}
// init callbacks
save_id_callback_ = save_id_callback;
forget_device_callback_ = forget_device_callback;
return initialized_ = true;
}
MetricIdAllocator::~MetricIdAllocator() { Close(); }
bool MetricIdAllocator::Close() {
std::lock_guard<std::mutex> lock(id_allocator_mutex_);
if (!initialized_) {
return false;
}
paired_device_cache_.Clear();
temporary_device_cache_.Clear();
id_set_.clear();
initialized_ = false;
return true;
}
MetricIdAllocator& MetricIdAllocator::GetInstance() {
static MetricIdAllocator metric_id_allocator;
return metric_id_allocator;
}
bool MetricIdAllocator::IsEmpty() const {
std::lock_guard<std::mutex> lock(id_allocator_mutex_);
return paired_device_cache_.Size() == 0 &&
temporary_device_cache_.Size() == 0;
}
// call this function when a new device is scanned
int MetricIdAllocator::AllocateId(const RawAddress& mac_address) {
std::lock_guard<std::mutex> lock(id_allocator_mutex_);
int id = 0;
// if already have an id, return it
if (paired_device_cache_.Get(mac_address, &id)) {
return id;
}
if (temporary_device_cache_.Get(mac_address, &id)) {
return id;
}
// find next available id
while (id_set_.count(next_id_) > 0) {
next_id_++;
if (next_id_ > kMaxId) {
next_id_ = kMinId;
LOG(WARNING) << LOGGING_TAG << "Bluetooth metric id overflow.";
}
}
id = next_id_++;
id_set_.insert(id);
auto evicted = temporary_device_cache_.Put(mac_address, id);
if (evicted) {
this->id_set_.erase(evicted->second);
}
if (next_id_ > kMaxId) {
next_id_ = kMinId;
}
return id;
}
// call this function when a device is paired
bool MetricIdAllocator::SaveDevice(const RawAddress& mac_address) {
std::lock_guard<std::mutex> lock(id_allocator_mutex_);
int id = 0;
if (paired_device_cache_.Get(mac_address, &id)) {
return true;
}
if (!temporary_device_cache_.Get(mac_address, &id)) {
LOG(ERROR) << LOGGING_TAG
<< "Failed to save device because device is not in "
<< "temporary_device_cache_";
return false;
}
if (!temporary_device_cache_.Remove(mac_address)) {
LOG(ERROR) << LOGGING_TAG
<< "Failed to remove device from temporary_device_cache_";
return false;
}
auto evicted = paired_device_cache_.Put(mac_address, id);
if (evicted) {
ForgetDevicePostprocess(evicted->first, evicted->second);
}
if (!save_id_callback_(mac_address, id)) {
LOG(ERROR) << LOGGING_TAG
<< "Callback returned false after saving the device";
return false;
}
return true;
}
// call this function when a device is forgotten
void MetricIdAllocator::ForgetDevice(const RawAddress& mac_address) {
std::lock_guard<std::mutex> lock(id_allocator_mutex_);
int id = 0;
if (!paired_device_cache_.Get(mac_address, &id)) {
LOG(ERROR) << LOGGING_TAG
<< "Failed to forget device because device is not in "
<< "paired_device_cache_";
return;
}
if (!paired_device_cache_.Remove(mac_address)) {
LOG(ERROR) << LOGGING_TAG
<< "Failed to remove device from paired_device_cache_";
return;
}
ForgetDevicePostprocess(mac_address, id);
}
bool MetricIdAllocator::IsValidId(const int id) {
return id >= kMinId && id <= kMaxId;
}
void MetricIdAllocator::ForgetDevicePostprocess(const RawAddress& mac_address,
const int id) {
id_set_.erase(id);
forget_device_callback_(mac_address, id);
}
} // namespace common
} // namespace bluetooth
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