device/bluetooth/bluetooth_adapter.h

// Copyright (c) 2012 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 DEVICE_BLUETOOTH_BLUETOOTH_ADAPTER_H_
#define DEVICE_BLUETOOTH_BLUETOOTH_ADAPTER_H_

#include <list>
#include <map>
#include <set>
#include <string>
#include <utility>

#include "base/callback.h"
#include "base/memory/ref_counted.h"
#include "base/memory/weak_ptr.h"
#include "device/bluetooth/bluetooth_device.h"

namespace device {

class BluetoothDiscoverySession;

struct BluetoothOutOfBandPairingData;

// BluetoothAdapter represents a local Bluetooth adapter which may be used to
// interact with remote Bluetooth devices. As well as providing support for
// determining whether an adapter is present and whether the radio is powered,
// this class also provides support for obtaining the list of remote devices
// known to the adapter, discovering new devices, and providing notification of
// updates to device information.
class BluetoothAdapter : public base::RefCounted<BluetoothAdapter> {
 public:
  // Interface for observing changes from bluetooth adapters.
  class Observer {
   public:
    virtual ~Observer() {}

    // Called when the presence of the adapter |adapter| changes. When |present|
    // is true the adapter is now present, false means the adapter has been
    // removed from the system.
    virtual void AdapterPresentChanged(BluetoothAdapter* adapter,
                                       bool present) {}

    // Called when the radio power state of the adapter |adapter| changes. When
    // |powered| is true the adapter radio is powered, false means the adapter
    // radio is off.
    virtual void AdapterPoweredChanged(BluetoothAdapter* adapter,
                                       bool powered) {}

    // Called when the discoverability state of the  adapter |adapter| changes.
    // When |discoverable| is true the adapter is discoverable by other devices,
    // false means the adapter is not discoverable.
    virtual void AdapterDiscoverableChanged(BluetoothAdapter* adapter,
                                           bool discoverable) {}

    // Called when the discovering state of the adapter |adapter| changes. When
    // |discovering| is true the adapter is seeking new devices, false means it
    // is not.
    virtual void AdapterDiscoveringChanged(BluetoothAdapter* adapter,
                                           bool discovering) {}

    // Called when a new device |device| is added to the adapter |adapter|,
    // either because it has been discovered or a connection made. |device|
    // should not be cached. Instead, copy its Bluetooth address.
    virtual void DeviceAdded(BluetoothAdapter* adapter,
                             BluetoothDevice* device) {}

    // Called when properties of the device |device| known to the adapter
    // |adapter| change. |device| should not be cached. Instead, copy its
    // Bluetooth address.
    virtual void DeviceChanged(BluetoothAdapter* adapter,
                               BluetoothDevice* device) {}

    // Called when the device |device| is removed from the adapter |adapter|,
    // either as a result of a discovered device being lost between discovering
    // phases or pairing information deleted. |device| should not be
    // cached. Instead, copy its Bluetooth address.
    virtual void DeviceRemoved(BluetoothAdapter* adapter,
                               BluetoothDevice* device) {}
  };

  // The ErrorCallback is used for methods that can fail in which case it is
  // called, in the success case the callback is simply not called.
  typedef base::Closure ErrorCallback;

  // The BluetoothOutOfBandPairingDataCallback is used to return
  // BluetoothOutOfBandPairingData to the caller.
  typedef base::Callback<void(const BluetoothOutOfBandPairingData& data)>
      BluetoothOutOfBandPairingDataCallback;

  // The InitCallback is used to trigger a callback after asynchronous
  // initialization, if initialization is asynchronous on the platform.
  typedef base::Callback<void()> InitCallback;

  // Returns a weak pointer to a new adapter.  For platforms with asynchronous
  // initialization, the returned adapter will run the |init_callback| once
  // asynchronous initialization is complete.
  // Caution: The returned pointer also transfers ownership of the adapter.  The
  // caller is expected to call |AddRef()| on the returned pointer, typically by
  // storing it into a |scoped_refptr|.
  static base::WeakPtr<BluetoothAdapter> CreateAdapter(
      const InitCallback& init_callback);

  // Returns a weak pointer to an existing adapter for testing purposes only.
  base::WeakPtr<BluetoothAdapter> GetWeakPtrForTesting();

  // Adds and removes observers for events on this bluetooth adapter. If
  // monitoring multiple adapters, check the |adapter| parameter of observer
  // methods to determine which adapter is issuing the event.
  virtual void AddObserver(BluetoothAdapter::Observer* observer) = 0;
  virtual void RemoveObserver(
      BluetoothAdapter::Observer* observer) = 0;

  // The address of this adapter. The address format is "XX:XX:XX:XX:XX:XX",
  // where each XX is a hexadecimal number.
  virtual std::string GetAddress() const = 0;

  // The name of the adapter.
  virtual std::string GetName() const = 0;

  // Set the human-readable name of the adapter to |name|. On success,
  // |callback| will be called. On failure, |error_callback| will be called.
  virtual void SetName(const std::string& name,
                       const base::Closure& callback,
                       const ErrorCallback& error_callback) = 0;

  // Indicates whether the adapter is initialized and ready to use.
  virtual bool IsInitialized() const = 0;

  // Indicates whether the adapter is actually present on the system. For the
  // default adapter, this indicates whether any adapter is present. An adapter
  // is only considered present if the address has been obtained.
  virtual bool IsPresent() const = 0;

  // Indicates whether the adapter radio is powered.
  virtual bool IsPowered() const = 0;

  // Requests a change to the adapter radio power. Setting |powered| to true
  // will turn on the radio and false will turn it off. On success, |callback|
  // will be called. On failure, |error_callback| will be called.
  virtual void SetPowered(bool powered,
                          const base::Closure& callback,
                          const ErrorCallback& error_callback) = 0;

  // Indicates whether the adapter radio is discoverable.
  virtual bool IsDiscoverable() const = 0;

  // Requests that the adapter change its discoverability state. If
  // |discoverable| is true, then it will be discoverable by other Bluetooth
  // devices. On successly changing the adapter's discoverability, |callback|
  // will be called. On failure, |error_callback| will be called.
  virtual void SetDiscoverable(bool discoverable,
                               const base::Closure& callback,
                               const ErrorCallback& error_callback) = 0;

  // Indicates whether the adapter is currently discovering new devices.
  virtual bool IsDiscovering() const = 0;

  // Requests the adapter to start a new discovery session. On success, a new
  // instance of BluetoothDiscoverySession will be returned to the caller via
  // |callback| and the adapter will be discovering nearby Bluetooth devices.
  // The returned BluetoothDiscoverySession is owned by the caller and it's the
  // owner's responsibility to properly clean it up and stop the session when
  // device discovery is no longer needed.
  //
  // If clients desire device discovery to run, they should always call this
  // method and never make it conditional on the value of IsDiscovering(), as
  // another client might cause discovery to stop unexpectedly. Hence, clients
  // should always obtain a BluetoothDiscoverySession and call
  // BluetoothDiscoverySession::Stop when done. When this method gets called,
  // device discovery may actually be in progress. Clients can call GetDevices()
  // and check for those with IsPaired() as false to obtain the list of devices
  // that have been discovered so far. Otherwise, clients can be notified of all
  // new and lost devices by implementing the Observer methods "DeviceAdded" and
  // "DeviceRemoved".
  typedef base::Callback<void(scoped_ptr<BluetoothDiscoverySession>)>
      DiscoverySessionCallback;
  virtual void StartDiscoverySession(const DiscoverySessionCallback& callback,
                                     const ErrorCallback& error_callback);

  // Requests the list of devices from the adapter. All devices are returned,
  // including those currently connected and those paired. Use the returned
  // device pointers to determine which they are.
  typedef std::vector<BluetoothDevice*> DeviceList;
  virtual DeviceList GetDevices();
  typedef std::vector<const BluetoothDevice*> ConstDeviceList;
  virtual ConstDeviceList GetDevices() const;

  // Returns a pointer to the device with the given address |address| or NULL if
  // no such device is known.
  virtual BluetoothDevice* GetDevice(const std::string& address);
  virtual const BluetoothDevice* GetDevice(const std::string& address) const;

  // Requests the local Out Of Band pairing data.
  virtual void ReadLocalOutOfBandPairingData(
      const BluetoothOutOfBandPairingDataCallback& callback,
      const ErrorCallback& error_callback) = 0;

  // Possible priorities for AddPairingDelegate(), low is intended for
  // permanent UI and high is intended for interactive UI or applications.
  enum PairingDelegatePriority {
    PAIRING_DELEGATE_PRIORITY_LOW,
    PAIRING_DELEGATE_PRIORITY_HIGH
  };

  // Adds a default pairing delegate with priority |priority|. Method calls
  // will be made on |pairing_delegate| for incoming pairing requests if the
  // priority is higher than any other registered; or for those of the same
  // priority, the first registered.
  //
  // |pairing_delegate| must not be freed without first calling
  // RemovePairingDelegate().
  virtual void AddPairingDelegate(
      BluetoothDevice::PairingDelegate* pairing_delegate,
      PairingDelegatePriority priority);

  // Removes a previously added pairing delegate.
  virtual void RemovePairingDelegate(
      BluetoothDevice::PairingDelegate* pairing_delegate);

  // Returns the first registered pairing delegate with the highest priority,
  // or NULL if no delegate is registered. Used to select the delegate for
  // incoming pairing requests.
  virtual BluetoothDevice::PairingDelegate* DefaultPairingDelegate();

 protected:
  friend class base::RefCounted<BluetoothAdapter>;
  friend class BluetoothDiscoverySession;
  BluetoothAdapter();
  virtual ~BluetoothAdapter();

  // Internal methods for initiating and terminating device discovery sessions.
  // An implementation of BluetoothAdapter keeps an internal reference count to
  // make sure that the underlying controller is constantly searching for nearby
  // devices and retrieving information from them as long as there are clients
  // who have requested discovery. These methods behave in the following way:
  //
  // On a call to AddDiscoverySession:
  //    - If there is a pending request to the subsystem, queue this request to
  //      execute once the pending requests are done.
  //    - If the count is 0, issue a request to the subsystem to start
  //      device discovery. On success, increment the count to 1.
  //    - If the count is greater than 0, increment the count and return
  //      success.
  //    As long as the count is non-zero, the underlying controller will be
  //    discovering for devices. This means that Chrome will restart device
  //    scan and inquiry sessions if they ever end, unless these sessions
  //    terminate due to an unexpected reason.
  //
  // On a call to RemoveDiscoverySession:
  //    - If there is a pending request to the subsystem, queue this request to
  //      execute once the pending requests are done.
  //    - If the count is 0, return failure, as there is no active discovery
  //      session.
  //    - If the count is 1, issue a request to the subsystem to stop device
  //      discovery and decrement the count to 0 on success.
  //    - If the count is greater than 1, decrement the count and return
  //      success.
  //
  // These methods invoke |callback| for success and |error_callback| for
  // failures.
  virtual void AddDiscoverySession(const base::Closure& callback,
                                   const ErrorCallback& error_callback) = 0;
  virtual void RemoveDiscoverySession(const base::Closure& callback,
                                      const ErrorCallback& error_callback) = 0;

  // Called by RemovePairingDelegate() in order to perform any class-specific
  // internal functionality necessary to remove the pairing delegate, such as
  // cleaning up ongoing pairings using it.
  virtual void RemovePairingDelegateInternal(
      BluetoothDevice::PairingDelegate* pairing_delegate) = 0;

  // Success callback passed to AddDiscoverySession by StartDiscoverySession.
  void OnStartDiscoverySession(const DiscoverySessionCallback& callback);

  // Marks all known DiscoverySession instances as inactive. Called by
  // BluetoothAdapter in the event that the adapter unexpectedly stops
  // discovering. This should be called by all platform implementations.
  void MarkDiscoverySessionsAsInactive();

  // Removes |discovery_session| from |discovery_sessions_|, if its in there.
  // Called by DiscoverySession when an instance is destroyed or becomes
  // inactive.
  void DiscoverySessionBecameInactive(
      BluetoothDiscoverySession* discovery_session);

  // Devices paired with, connected to, discovered by, or visible to the
  // adapter. The key is the Bluetooth address of the device and the value is
  // the BluetoothDevice object whose lifetime is managed by the adapter
  // instance.
  typedef std::map<const std::string, BluetoothDevice*> DevicesMap;
  DevicesMap devices_;

  // Default pairing delegates registered with the adapter.
  typedef std::pair<BluetoothDevice::PairingDelegate*,
                    PairingDelegatePriority> PairingDelegatePair;
  std::list<PairingDelegatePair> pairing_delegates_;

 private:
  // List of active DiscoverySession objects. This is used to notify sessions to
  // become inactive in case of an unexpected change to the adapter discovery
  // state. We keep raw pointers, with the invariant that a DiscoverySession
  // will remove itself from this list when it gets destroyed or becomes
  // inactive by calling DiscoverySessionBecameInactive(), hence no pointers to
  // deallocated sessions are kept.
  std::set<BluetoothDiscoverySession*> discovery_sessions_;

  // Note: This should remain the last member so it'll be destroyed and
  // invalidate its weak pointers before any other members are destroyed.
  base::WeakPtrFactory<BluetoothAdapter> weak_ptr_factory_;
};

}  // namespace device

#endif  // DEVICE_BLUETOOTH_BLUETOOTH_ADAPTER_H_