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// Copyright 2018 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "chromeos/ash/components/tether/connection_preserver_impl.h"
#include <algorithm>
#include "base/functional/bind.h"
#include "base/timer/timer.h"
#include "chromeos/ash/components/multidevice/logging/logging.h"
#include "chromeos/ash/components/network/network_state.h"
#include "chromeos/ash/components/network/network_state_handler.h"
#include "chromeos/ash/components/network/network_type_pattern.h"
#include "chromeos/ash/components/tether/tether_host_response_recorder.h"
namespace ash::tether {
ConnectionPreserverImpl::ConnectionPreserverImpl(
HostConnection::Factory* host_connection_factory,
NetworkStateHandler* network_state_handler,
ActiveHost* active_host,
TetherHostResponseRecorder* tether_host_response_recorder)
: host_connection_factory_(host_connection_factory),
network_state_handler_(network_state_handler),
active_host_(active_host),
tether_host_response_recorder_(tether_host_response_recorder),
preserved_connection_timer_(std::make_unique<base::OneShotTimer>()) {
active_host_->AddObserver(this);
}
ConnectionPreserverImpl::~ConnectionPreserverImpl() {
active_host_->RemoveObserver(this);
RemovePreservedConnectionIfPresent();
}
void ConnectionPreserverImpl::HandleSuccessfulTetherAvailabilityResponse(
const std::string& device_id) {
DCHECK(!device_id.empty());
// Do not bother preserving a BLE Connection if the device is already
// connected to the Internet. BLE and Wi-Fi share the same antenna, so keeping
// a BLE connection open while there's an active Wi-Fi connection would
// degrade the Wi-Fi network's performance.
if (IsConnectedToInternet()) {
return;
}
// No BLE Connection has been preserved yet, so simply preserve this first
// request.
if (preserved_connection_device_id_.empty()) {
SetPreservedConnection(device_id);
return;
}
// If the requested |device_id| is a higher priority than the current
// preserved Connection, make it the new preserved Connection. Only a single
// BLE Connection is preserved at once (there are negative performance
// implications with keeping multiple open).
if (preserved_connection_device_id_ !=
GetPreferredPreservedConnectionDeviceId(device_id)) {
RemovePreservedConnectionIfPresent();
SetPreservedConnection(device_id);
} else {
PA_LOG(VERBOSE)
<< "The connection to device with ID "
<< TetherHost::TruncateDeviceIdForLogs(device_id)
<< " was not preserved; another device has higher priority.";
}
}
void ConnectionPreserverImpl::OnDisconnected() {
PA_LOG(VERBOSE) << "Remote device disconnected from this device: "
<< TetherHost::TruncateDeviceIdForLogs(
preserved_connection_device_id_);
RemovePreservedConnectionIfPresent();
}
void ConnectionPreserverImpl::OnMessageReceived(
std::unique_ptr<MessageWrapper> message_wrapper) {
// Do nothing.
}
void ConnectionPreserverImpl::OnConnectionAttemptFinished(
std::unique_ptr<HostConnection> host_connection) {
if (!host_connection) {
PA_LOG(WARNING) << "Failed to connect to device "
<< TetherHost::TruncateDeviceIdForLogs(
preserved_connection_device_id_);
RemovePreservedConnectionIfPresent();
} else {
preserved_host_connection_ = std::move(host_connection);
PA_LOG(VERBOSE) << "Successfully preserved connection for device: "
<< TetherHost::TruncateDeviceIdForLogs(
preserved_connection_device_id_);
}
}
void ConnectionPreserverImpl::OnActiveHostChanged(
const ActiveHost::ActiveHostChangeInfo& change_info) {
if (change_info.new_status == ActiveHost::ActiveHostStatus::CONNECTED) {
RemovePreservedConnectionIfPresent();
}
}
bool ConnectionPreserverImpl::IsConnectedToInternet() {
// If a network is active (i.e., connecting or connected), it will be returned
// at the front of the list, so using FirstNetworkByType() guarantees that we
// will find an active network if there is one.
const NetworkState* first_network =
network_state_handler_->FirstNetworkByType(NetworkTypePattern::Default());
return first_network && first_network->IsConnectingOrConnected();
}
std::string ConnectionPreserverImpl::GetPreferredPreservedConnectionDeviceId(
const std::string& device_id) {
DCHECK(!preserved_connection_device_id_.empty());
// Between |device_id| and |preserved_connection_device_id_|, prefer whichever
// appears in |previously_connected_host_ids| first, since
// |previously_connected_host_ids| is ordered with most recently connected
// hosts first. |device_id| is preferred over
// |preserved_connection_device_id_| as a tie-breaker.
std::vector<std::string> previously_connected_host_ids =
tether_host_response_recorder_->GetPreviouslyConnectedHostIds();
const auto preferred_connection_id_it = std::ranges::find_if(
previously_connected_host_ids,
[this, &device_id](auto previously_connected_id) {
// Pick out whichever ID appears in the list first.
return previously_connected_id == device_id ||
previously_connected_id == preserved_connection_device_id_;
});
std::string preferred_connection_id =
preferred_connection_id_it != previously_connected_host_ids.end()
? *preferred_connection_id_it
: device_id;
return preferred_connection_id;
}
void ConnectionPreserverImpl::SetPreservedConnection(
const std::string& device_id) {
DCHECK(preserved_connection_device_id_.empty());
PA_LOG(VERBOSE) << "Preserving connection to device with ID "
<< TetherHost::TruncateDeviceIdForLogs(device_id) << ".";
preserved_connection_device_id_ = device_id;
host_connection_factory_->ScanForTetherHostAndCreateConnection(
device_id, HostConnection::Factory::ConnectionPriority::kLow,
/*payload_listener=*/this,
base::BindOnce(&ConnectionPreserverImpl::OnDisconnected,
weak_ptr_factory_.GetWeakPtr()),
base::BindOnce(&ConnectionPreserverImpl::OnConnectionAttemptFinished,
weak_ptr_factory_.GetWeakPtr()));
preserved_connection_timer_->Start(
FROM_HERE, base::Seconds(kTimeoutSeconds),
base::BindOnce(
&ConnectionPreserverImpl::RemovePreservedConnectionIfPresent,
weak_ptr_factory_.GetWeakPtr()));
}
void ConnectionPreserverImpl::RemovePreservedConnectionIfPresent() {
if (preserved_connection_device_id_.empty()) {
return;
}
PA_LOG(VERBOSE) << "Removing preserved connection to device with ID "
<< TetherHost::TruncateDeviceIdForLogs(
preserved_connection_device_id_)
<< ".";
preserved_host_connection_.reset();
preserved_connection_device_id_.clear();
preserved_connection_timer_->Stop();
}
void ConnectionPreserverImpl::SetTimerForTesting(
std::unique_ptr<base::OneShotTimer> timer_for_test) {
preserved_connection_timer_ = std::move(timer_for_test);
}
} // namespace ash::tether
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