[CrOS Tether] Create TetherHostResponseRecorder, which records ConnectTetheringResponses and Tether…

chromeos/components/tether/tether_host_response_recorder.cc

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chromeos/components/tether/tether_host_response_recorder.h"
+
+#include "base/memory/ptr_util.h"
+#include "base/values.h"
+#include "chromeos/components/tether/pref_names.h"
+#include "components/prefs/pref_registry_simple.h"
+#include "components/prefs/pref_service.h"
+
+namespace chromeos {
+
+namespace tether {
+
+// static
+void TetherHostResponseRecorder::RegisterPrefs(PrefRegistrySimple* registry) {
+  registry->RegisterListPref(prefs::kMostRecentTetherAvailablilityResponderIds);
+  registry->RegisterListPref(prefs::kMostRecentConnectTetheringResponderIds);
+}
+
+TetherHostResponseRecorder::TetherHostResponseRecorder(
+    PrefService* pref_service)
+    : pref_service_(pref_service) {}
+
+TetherHostResponseRecorder::~TetherHostResponseRecorder() {}
+
+void TetherHostResponseRecorder::RecordSuccessfulTetherAvailabilityResponse(
+    const cryptauth::RemoteDevice& remote_device) {
+  AddRecentResponse(remote_device.GetDeviceId(),
+                    prefs::kMostRecentTetherAvailablilityResponderIds);
+}
+
+std::vector<std::string>
+TetherHostResponseRecorder::GetPreviouslyAvailableHostIds() const {
+  return GetDeviceIdsForPref(prefs::kMostRecentTetherAvailablilityResponderIds);
+}
+
+void TetherHostResponseRecorder::RecordSuccessfulConnectTetheringResponse(
+    const cryptauth::RemoteDevice& remote_device) {
+  AddRecentResponse(remote_device.GetDeviceId(),
+                    prefs::kMostRecentConnectTetheringResponderIds);
+}
+
+std::vector<std::string>
+TetherHostResponseRecorder::GetPreviouslyConnectedHostIds() const {
+  return GetDeviceIdsForPref(prefs::kMostRecentConnectTetheringResponderIds);
+}
+
+void TetherHostResponseRecorder::AddRecentResponse(
+    const std::string& device_id,
+    const std::string& pref_name) {
+  const base::ListValue* ids = pref_service_->GetList(pref_name);
+
+  // Create a mutable copy of the stored IDs, or create one if it has yet to be
+  // stored.
+  std::unique_ptr<base::ListValue> updated_ids =
+      ids ? ids->CreateDeepCopy() : base::MakeUnique<base::ListValue>();
+
+  // Remove the device ID if it was already present in the list.
+  std::unique_ptr<base::Value> device_id_value =
+      base::MakeUnique<base::Value>(device_id);
+  updated_ids->Remove(*device_id_value, nullptr);
+
+  // Add the device ID to the front of the queue.
+  updated_ids->Insert(0, std::move(device_id_value));
+
+  // Store the updated list back in |pref_service_|.
+  pref_service_->Set(pref_name, *updated_ids);
+}
+
+std::vector<std::string> TetherHostResponseRecorder::GetDeviceIdsForPref(
+    const std::string& pref_name) const {
+  std::vector<std::string> device_ids;
+
+  const base::ListValue* ids = pref_service_->GetList(pref_name);
+  if (!ids)
+    return device_ids;
+
+  for (auto it = ids->begin(); it != ids->end(); ++it) {
+    std::string device_id;
+    bool success = it->GetAsString(&device_id);
+    if (success)
+      device_ids.push_back(device_id);
+  }
+
+  return device_ids;
+}
+
+}  // namespace tether
+
+}  // namespace chromeos