1 // Copyright 2014 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 DEVICE_BLUETOOTH_BLUETOOTH_DISCOVERY_SESSION_H_ 6 #define DEVICE_BLUETOOTH_BLUETOOTH_DISCOVERY_SESSION_H_ 7 8 #include "base/callback.h" 9 #include "base/memory/ref_counted.h" 10 #include "base/memory/weak_ptr.h" 11 12 namespace device { 13 14 class BluetoothAdapter; 15 16 // BluetoothDiscoverySession represents a current active or inactive device 17 // discovery session. Instances of this class are obtained by calling 18 // BluetoothAdapter::StartDiscoverySession. The Bluetooth adapter will be 19 // constantly searching for nearby devices, as long as at least one instance 20 // of an active BluetoothDiscoverySession exists. A BluetoothDiscoverySession is 21 // considered active, as long as the adapter is discovering AND the owner of the 22 // instance has not called BluetoothDiscoverySession::Stop. A 23 // BluetoothDiscoverySession might unexpectedly become inactive, if the adapter 24 // unexpectedly stops discovery. Users can implement the 25 // AdapterDiscoveringChanged method of the BluetoothAdapter::Observer interface 26 // to be notified of such a change and promptly request a new 27 // BluetoothDiscoverySession if their existing sessions have become inactive. 28 class BluetoothDiscoverySession { 29 public: 30 // The ErrorCallback is used by methods to asynchronously report errors. 31 typedef base::Closure ErrorCallback; 32 33 // Destructor automatically terminates the discovery session. If this 34 // results in a call to the underlying system to stop device discovery 35 // (i.e. this instance represents the last active discovery session), 36 // the call may not always succeed. To be notified of such failures, 37 // users are highly encouraged to call BluetoothDiscoverySession::Stop, 38 // instead of relying on the destructor. 39 virtual ~BluetoothDiscoverySession(); 40 41 // Returns true if the session is active, false otherwise. If false, the 42 // adapter might still be discovering as there might still be other active 43 // sessions; this just means that this instance no longer has a say in 44 // whether or not discovery should continue. In this case, the application 45 // should request a new BluetoothDiscoverySession to make sure that device 46 // discovery continues. 47 virtual bool IsActive() const; 48 49 // Requests this discovery session instance to stop. If this instance is 50 // active, the session will stop. On success, |callback| is called and 51 // on error |error_callback| is called. After a successful invocation, the 52 // adapter may or may not stop device discovery, depending on whether or not 53 // other active discovery sessions are present. Users are highly encouraged 54 // to call this method to end a discovery session, instead of relying on the 55 // destructor, so that they can be notified of the result via the callback 56 // arguments. 57 virtual void Stop(const base::Closure& callback, 58 const ErrorCallback& error_callback); 59 60 protected: 61 explicit BluetoothDiscoverySession(scoped_refptr<BluetoothAdapter> adapter); 62 63 private: 64 friend class BluetoothAdapter; 65 66 // Internal callback invoked when a call to Stop has succeeded. 67 void OnStop(const base::Closure& callback); 68 69 // Marks this instance as inactive. Called by BluetoothAdapter to mark a 70 // session as inactive in the case of an unexpected change to the adapter 71 // discovery state. 72 void MarkAsInactive(); 73 74 // Whether or not this instance represents an active discovery session. 75 bool active_; 76 77 // The adapter that created this instance. 78 scoped_refptr<BluetoothAdapter> adapter_; 79 80 // Note: This should remain the last member so it'll be destroyed and 81 // invalidate its weak pointers before any other members are destroyed. 82 base::WeakPtrFactory<BluetoothDiscoverySession> weak_ptr_factory_; 83 84 DISALLOW_COPY_AND_ASSIGN(BluetoothDiscoverySession); 85 }; 86 87 } // namespace device 88 89 #endif // DEVICE_BLUETOOTH_BLUETOOTH_DISCOVERY_SESSION_H_ 90