components/proximity_auth/bluetooth_throttler_impl.h

   1 // Copyright 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef COMPONENTS_PROXIMITY_AUTH_BLUETOOTH_THROTTLER_IMPL_H
   6 #define COMPONENTS_PROXIMITY_AUTH_BLUETOOTH_THROTTLER_IMPL_H
   7
   8 #include <set>
   9
  10 #include "base/macros.h"
  11 #include "base/memory/scoped_ptr.h"
  12 #include "base/time/time.h"
  13 #include "components/proximity_auth/bluetooth_throttler.h"
  14 #include "components/proximity_auth/connection_observer.h"
  15
  16 namespace base {
  17 class TickClock;
  18 }
  19
  20 namespace proximity_auth {
  21
  22 class Connection;
  23
  24 // This class throttles repeated connection attempts to the same device. This
  25 // throttling is necessary to prevent a kernel race condition when connecting
  26 // before the previous connection fully closes, putting the connection in a
  27 // corrupted, and unrecoverable state. http://crbug.com/345232
  28 class BluetoothThrottlerImpl : public BluetoothThrottler,
  29                                public ConnectionObserver {
  30  public:
  31   // Creates a throttler for connections to a remote device, using the |clock|
  32   // as a time source.
  33   explicit BluetoothThrottlerImpl(scoped_ptr<base::TickClock> clock);
  34   ~BluetoothThrottlerImpl() override;
  35
  36   // BluetoothThrottler:
  37   base::TimeDelta GetDelay() const override;
  38   void OnConnection(Connection* connection) override;
  39
  40  protected:
  41   // Returns the duration to wait, after disconnecting, before reattempting a
  42   // connection to the remote device. Exposed for testing.
  43   base::TimeDelta GetCooldownTimeDelta() const;
  44
  45  private:
  46   // ConnectionObserver:
  47   void OnConnectionStatusChanged(Connection* connection,
  48                                  Connection::Status old_status,
  49                                  Connection::Status new_status) override;
  50
  51   // Tracks the last seen disconnect time for the |remote_device_|.
  52   base::TimeTicks last_disconnect_time_;
  53
  54   // The time source.
  55   scoped_ptr<base::TickClock> clock_;
  56
  57   // The currently connected connections.
  58   // Each connection is stored as a weak reference, which is safe because |this|
  59   // instance is registered as an observer, and will unregister when the
  60   // connection disconnects, which is guaranteed to occur before the connection
  61   // is destroyed.
  62   std::set<Connection*> connections_;
  63
  64   DISALLOW_COPY_AND_ASSIGN(BluetoothThrottlerImpl);
  65 };
  66
  67 }  // namespace proximity_auth
  68
  69 #endif  // COMPONENTS_PROXIMITY_AUTH_BLUETOOTH_THROTTLER_IMPL_H