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

chromeos/components/tether/tether_host_response_recorder.h

Index: chromeos/components/tether/tether_host_response_recorder.h
diff --git a/chromeos/components/tether/tether_host_response_recorder.h b/chromeos/components/tether/tether_host_response_recorder.h
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+++ b/chromeos/components/tether/tether_host_response_recorder.h
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+// 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.
+
+#ifndef CHROMEOS_COMPONENTS_TETHER_TETHER_HOST_RESPONSE_RECORDER_H_
+#define CHROMEOS_COMPONENTS_TETHER_TETHER_HOST_RESPONSE_RECORDER_H_
+
+#include <string>
+#include <vector>
+
+#include "base/macros.h"
+#include "components/cryptauth/remote_device.h"
+
+class PrefService;
+class PrefRegistrySimple;
+
+namespace chromeos {
+
+namespace tether {
+
+// Records responses from tether hosts in user prefs, which persists these
+// responses between reboots of the device. When a TetherAvailabilityResponse or
+// ConnectTetheringResponse is received, it should be recorded using this class.
+// Responses can be retrieved at a later time via getter methods.
+class TetherHostResponseRecorder {
+ public:
+  // Note: The PrefService* passed here must be created using the same registry
+  // passed to RegisterPrefs().
+  TetherHostResponseRecorder(PrefService* pref_service);
+  virtual ~TetherHostResponseRecorder();
+
+  // Registers the prefs used by this class to |registry|. Must be called before
+  // this class is utilized.
+  static void RegisterPrefs(PrefRegistrySimple* registry);
+
+  // Records a TetherAvailabilityResponse. This function should be called each
+  // time that a response is received from a potential host, even if a
+  // connection is not started.
+  virtual void RecordSuccessfulTetherAvailabilityResponse(
+      const cryptauth::RemoteDevice& remote_device);
+
+  // Gets device IDs corresponding to hosts which have sent
+  // TetherAvailabilityResponses with a response code indicating that tethering
+  // is available. The list is sorted; the IDs of the devices which have
+  // responded most recently are at the front of the list and the IDs of the
+  // devices which have responded least recently are at the end of the list.
+  virtual std::vector<std::string> GetPreviouslyAvailableHostIds() const;
+
+  // Records a ConnectTetheringResponse. This function should be called each
+  // time that a response is received from a host.
+  virtual void RecordSuccessfulConnectTetheringResponse(
+      const cryptauth::RemoteDevice& remote_device);
+
+  // Gets device IDs corresponding to hosts which have sent
+  // ConnectTetheringResponses with a response code indicating that they have
+  // successfully turned on their Wi-Fi hotspots. The list is sorted; the IDs of
+  // the devices which have responded most recently are at the front of the list
+  // and the IDs of the devices which have responded least recently are at the
+  // end of the list.
+  virtual std::vector<std::string> GetPreviouslyConnectedHostIds() const;
+
+ private:
+  void AddRecentResponse(const std::string& device_id,
+                         const std::string& pref_name);
+  std::vector<std::string> GetDeviceIdsForPref(
+      const std::string& pref_name) const;
+
+  PrefService* pref_service_;
+
+  DISALLOW_COPY_AND_ASSIGN(TetherHostResponseRecorder);
+};
+
+}  // namespace tether
+
+}  // namespace chromeos
+
+#endif  // CHROMEOS_COMPONENTS_TETHER_TETHER_HOST_RESPONSE_RECORDER_H_