[CrOS Tether] Create the ActiveHost class, which stores metadata related to the current connection …

chromeos/components/tether/active_host.h

Index: chromeos/components/tether/active_host.h
diff --git a/chromeos/components/tether/active_host.h b/chromeos/components/tether/active_host.h
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+++ b/chromeos/components/tether/active_host.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_ACTIVE_HOST_H_
+#define CHROMEOS_COMPONENTS_TETHER_ACTIVE_HOST_H_
+
+#include <string>
+
+#include "base/callback.h"
+#include "base/macros.h"
+#include "base/memory/weak_ptr.h"
+
+class PrefRegistrySimple;
+class PrefService;
+
+namespace cryptauth {
+struct RemoteDevice;
+}  // namespace cryptauth
+
+namespace chromeos {
+
+namespace tether {
+
+class TetherHostFetcher;
+
+// ActiveHost tracks metadata about the current connection to a tether host.
+// This data is persisted to user preferences.
+class ActiveHost {
+ public:
+  // Enumeration used to describe the state of the active connection to a tether
+  // host.
+  enum class ActiveHostStatus {
+    DISCONNECTED = 0,
+    CONNECTING = 1,
+    CONNECTED = 2
+  };
+
+  ActiveHost(TetherHostFetcher* tether_host_fetcher, PrefService* pref_service);
+  virtual ~ActiveHost();
+
+  // Registers the prefs used by this class to the given |registry|.
+  static void RegisterPrefs(PrefRegistrySimple* registry);
+
+  // Sets the active host to be no host at all (i.e., the local device is not
+  // connecting or connected to a tether host).
+  void SetActiveHostDisconnected();
+
+  // Sets the active host to be the device with ID |active_host_device_id| and
+  // records that the there is an active attempt to connect to that host (i.e.,
+  // the host is not yet connected but it is in the process of connecting).
+  void SetActiveHostConnecting(const std::string& active_host_device_id);
+
+  // Sets the active host to be the device with ID |active_host_device_id| and
+  // that the local device is connected to that device on the mobile hotspot
+  // with network ID |tether_network_id|.
+  void SetActiveHostConnected(const std::string& active_host_device_id,
+                              const std::string& tether_network_id);
+
+  // Gets the active host and associated metadata asynchronously. If
+  // the active host status is...
+  //     DISCONNECTED: The callback's |active_host| parameter will be nullptr
+  //                   and |tether_network_id| parameter will be "".
+  //     CONNECTING: The callback's |tether_network_id| will be "".
+  //     CONNECTED: All three parameter  will be present.
+  using ActiveHostCallback =
+      base::Callback<void(ActiveHostStatus active_host_status,
+                          std::unique_ptr<cryptauth::RemoteDevice> active_host,
+                          const std::string& tether_network_id)>;
+  void GetActiveHost(const ActiveHostCallback& active_host_callback);
+
+  // Synchronous getter methods which do not return a full RemoteDevice object.
+  ActiveHostStatus GetActiveHostStatus() const;
+  const std::string GetActiveHostDeviceId() const;
+  const std::string GetTetherNetworkId() const;
+
+ private:
+  void SetActiveHost(ActiveHostStatus active_host_status,
+                     const std::string& active_host_device_id,
+                     const std::string& tether_network_id);
+
+  void OnTetherHostFetched(
+      const ActiveHostCallback& active_host_callback,
+      std::unique_ptr<cryptauth::RemoteDevice> remote_device);
+
+  TetherHostFetcher* tether_host_fetcher_;
+  PrefService* pref_service_;
+
+  base::WeakPtrFactory<ActiveHost> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(ActiveHost);
+};
+
+}  // namespace tether
+
+}  // namespace chromeos
+
+#endif  // CHROMEOS_COMPONENTS_TETHER_ACTIVE_HOST_H_