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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.
*
******************************************************************************/
#define LOG_TAG "BluetoothMetricIdManager"
#include <functional>
#include <iterator>
#include <mutex>
#include <optional>
#include <thread>
#include "os/log.h"
#include "common/metric_id_manager.h"
namespace bluetooth {
namespace common {
using hci::Address;
const size_t MetricIdManager::kMaxNumUnpairedDevicesInMemory = 200;
const size_t MetricIdManager::kMaxNumPairedDevicesInMemory = 65000;
const int MetricIdManager::kMinId = 1;
const int MetricIdManager::kMaxId = 65534; // 2^16 - 2
// id space should always be larger than kMaxNumPairedDevicesInMemory +
// kMaxNumUnpairedDevicesInMemory
static_assert((MetricIdManager::kMaxNumUnpairedDevicesInMemory +
MetricIdManager::kMaxNumPairedDevicesInMemory) <
(MetricIdManager::kMaxId - MetricIdManager::kMinId),
"id space should always be larger than "
"kMaxNumPairedDevicesInMemory + MaxNumUnpairedDevicesInMemory");
MetricIdManager::MetricIdManager()
: paired_device_cache_(kMaxNumPairedDevicesInMemory),
temporary_device_cache_(kMaxNumUnpairedDevicesInMemory) {}
bool MetricIdManager::Init(
const std::unordered_map<Address, 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_ALWAYS_FATAL(
"Paired device map has size %zu, which is bigger than "
"kMaxNumPairedDevicesInMemory %zu",
paired_device_map.size(), 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_ALWAYS_FATAL("Invalid Bluetooth Metric Id in config. "
"Id %d of %s is out of range [%d, %d]",
p.second, p.first.ToString().c_str(), kMinId, kMaxId);
}
auto evicted = paired_device_cache_.insert_or_assign(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;
}
MetricIdManager::~MetricIdManager() { Close(); }
bool MetricIdManager::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;
}
MetricIdManager& MetricIdManager::GetInstance() {
static MetricIdManager metric_id_allocator;
return metric_id_allocator;
}
bool MetricIdManager::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 MetricIdManager::AllocateId(const Address& mac_address) {
std::lock_guard<std::mutex> lock(id_allocator_mutex_);
auto it = paired_device_cache_.find(mac_address);
// if already have an id, return it
if (it != paired_device_cache_.end()) {
return it->second;
}
it = temporary_device_cache_.find(mac_address);
if (it != temporary_device_cache_.end()) {
return it->second;
}
// find next available id
while (id_set_.count(next_id_) > 0) {
next_id_++;
if (next_id_ > kMaxId) {
next_id_ = kMinId;
LOG_WARN("Bluetooth metric id overflow.");
}
}
int id = next_id_++;
id_set_.insert(id);
auto evicted = temporary_device_cache_.insert_or_assign(mac_address, id);
if (evicted) {
this->id_set_.extract(evicted->second);
}
if (next_id_ > kMaxId) {
next_id_ = kMinId;
}
return id;
}
// call this function when a device is paired
bool MetricIdManager::SaveDevice(const Address& mac_address) {
std::lock_guard<std::mutex> lock(id_allocator_mutex_);
if (paired_device_cache_.contains(mac_address)) {
return true;
}
if (!temporary_device_cache_.contains(mac_address)) {
LOG_ERROR("Failed to save device because device is not in "
"temporary_device_cache_");
return false;
}
auto opt = temporary_device_cache_.extract(mac_address);
if (!opt) {
LOG_ERROR("Failed to remove device from temporary_device_cache_");
return false;
}
int id = opt->second;
auto evicted = paired_device_cache_.insert_or_assign(mac_address, id);
if (evicted) {
ForgetDevicePostprocess(evicted->first, evicted->second);
}
if (!save_id_callback_(mac_address, id)) {
LOG_ERROR("Callback returned false after saving the device");
return false;
}
return true;
}
// call this function when a device is forgotten
void MetricIdManager::ForgetDevice(const Address& mac_address) {
std::lock_guard<std::mutex> lock(id_allocator_mutex_);
auto opt = paired_device_cache_.extract(mac_address);
if (!opt) {
LOG_ERROR("Failed to remove device from paired_device_cache_");
return;
}
ForgetDevicePostprocess(mac_address, opt->second);
}
bool MetricIdManager::IsValidId(const int id) {
return id >= kMinId && id <= kMaxId;
}
void MetricIdManager::ForgetDevicePostprocess(const Address& mac_address,
const int id) {
id_set_.erase(id);
forget_device_callback_(mac_address, id);
}
} // namespace common
} // namespace bluetooth
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