chromeos/dbus/bluetooth_gatt_characteristic_client.h

   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 CHROMEOS_DBUS_BLUETOOTH_GATT_CHARACTERISTIC_CLIENT_H_
   6 #define CHROMEOS_DBUS_BLUETOOTH_GATT_CHARACTERISTIC_CLIENT_H_
   7
   8 #include <string>
   9 #include <vector>
  10
  11 #include "base/basictypes.h"
  12 #include "base/callback.h"
  13 #include "chromeos/chromeos_export.h"
  14 #include "chromeos/dbus/dbus_client.h"
  15 #include "dbus/object_path.h"
  16 #include "dbus/property.h"
  17
  18 namespace chromeos {
  19
  20 // BluetoothGattCharacteristicClient is used to communicate with remote GATT
  21 // characteristic objects exposed by the Bluetooth daemon.
  22 class CHROMEOS_EXPORT BluetoothGattCharacteristicClient : public DBusClient {
  23  public:
  24   // Structure of properties associated with GATT characteristics.
  25   struct Properties : public dbus::PropertySet {
  26     // The 128-bit characteristic UUID. [read-only]
  27     dbus::Property<std::string> uuid;
  28
  29     // Object path of the GATT service the characteristic belongs to.
  30     // [read-only]
  31     dbus::Property<dbus::ObjectPath> service;
  32
  33     // The cached value of the characteristic. This property gets updated only
  34     // after a successful read request and when a notification or indication is
  35     // received. [read-only]
  36     dbus::Property<std::vector<uint8_t>> value;
  37
  38     // Whether or not this characteristic is currently sending ValueUpdated
  39     // signals. [read-only]
  40     dbus::Property<bool> notifying;
  41
  42     // List of flags representing the GATT "Characteristic Properties bit field"
  43     // and properties read from the GATT "Characteristic Extended Properties"
  44     // descriptor bit field. [read-only, optional]
  45     dbus::Property<std::vector<std::string>> flags;
  46
  47     // Array of object paths representing the descriptors of this
  48     // characteristic. [read-only]
  49     dbus::Property<std::vector<dbus::ObjectPath>> descriptors;
  50
  51     Properties(dbus::ObjectProxy* object_proxy,
  52                const std::string& interface_name,
  53                const PropertyChangedCallback& callback);
  54     ~Properties() override;
  55   };
  56
  57   // Interface for observing changes from a remote GATT characteristic.
  58   class Observer {
  59    public:
  60     virtual ~Observer() {}
  61
  62     // Called when the GATT characteristic with object path |object_path| is
  63     // added to the system.
  64     virtual void GattCharacteristicAdded(const dbus::ObjectPath& object_path) {}
  65
  66     // Called when the GATT characteristic with object path |object_path| is
  67     // removed from the system.
  68     virtual void GattCharacteristicRemoved(
  69         const dbus::ObjectPath& object_path) {}
  70
  71     // Called when the GATT characteristic with object path |object_path| has a
  72     // change in the value of the property named |property_name|.
  73     virtual void GattCharacteristicPropertyChanged(
  74         const dbus::ObjectPath& object_path,
  75         const std::string& property_name) {}
  76   };
  77
  78   // Callbacks used to report the result of asynchronous methods.
  79   typedef base::Callback<void(const std::string& error_name,
  80                               const std::string& error_message)> ErrorCallback;
  81   typedef base::Callback<void(const std::vector<uint8>& value)> ValueCallback;
  82
  83   ~BluetoothGattCharacteristicClient() override;
  84
  85   // Adds and removes observers for events on all remote GATT characteristics.
  86   // Check the |object_path| parameter of observer methods to determine which
  87   // GATT characteristic is issuing the event.
  88   virtual void AddObserver(Observer* observer) = 0;
  89   virtual void RemoveObserver(Observer* observer) = 0;
  90
  91   // Returns the list of GATT characteristic object paths known to the system.
  92   virtual std::vector<dbus::ObjectPath> GetCharacteristics() = 0;
  93
  94   // Obtain the properties for the GATT characteristic with object path
  95   // |object_path|. Values should be copied if needed.
  96   virtual Properties* GetProperties(const dbus::ObjectPath& object_path) = 0;
  97
  98   // Issues a request to read the value of GATT characteristic with object path
  99   // |object_path| and returns the value in |callback| on success. On error,
 100   // invokes |error_callback|.
 101   virtual void ReadValue(const dbus::ObjectPath& object_path,
 102                          const ValueCallback& callback,
 103                          const ErrorCallback& error_callback) = 0;
 104
 105   // Issues a request to write the value of GATT characteristic with object path
 106   // |object_path| with value |value|. Invokes |callback| on success and
 107   // |error_callback| on failure.
 108   virtual void WriteValue(const dbus::ObjectPath& object_path,
 109                           const std::vector<uint8>& value,
 110                           const base::Closure& callback,
 111                           const ErrorCallback& error_callback) = 0;
 112
 113   // Starts a notification session from this characteristic with object path
 114   // |object_path| if it supports value notifications or indications. Invokes
 115   // |callback| on success and |error_callback| on failure.
 116   virtual void StartNotify(const dbus::ObjectPath& object_path,
 117                            const base::Closure& callback,
 118                            const ErrorCallback& error_callback) = 0;
 119
 120   // Cancels any previous StartNotify transaction for characteristic with
 121   // object path |object_path|. Invokes |callback| on success and
 122   // |error_callback| on failure.
 123   virtual void StopNotify(const dbus::ObjectPath& object_path,
 124                           const base::Closure& callback,
 125                           const ErrorCallback& error_callback) = 0;
 126
 127   // Creates the instance.
 128   static BluetoothGattCharacteristicClient* Create();
 129
 130   // Constants used to indicate exceptional error conditions.
 131   static const char kNoResponseError[];
 132   static const char kUnknownCharacteristicError[];
 133
 134  protected:
 135   BluetoothGattCharacteristicClient();
 136
 137  private:
 138   DISALLOW_COPY_AND_ASSIGN(BluetoothGattCharacteristicClient);
 139 };
 140
 141 }  // namespace chromeos
 142
 143 #endif  // CHROMEOS_DBUS_BLUETOOTH_GATT_CHARACTERISTIC_CLIENT_H_