bluetooth: Add control for reading/writing of characteristics to internals page.

device/bluetooth/public/interfaces/device.mojom

 // Copyright 2016 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.
 
 module bluetooth.mojom;
 
 import "device/bluetooth/public/interfaces/uuid.mojom";
 
 // Values representing the possible properties of a characteristic, which
 // define how the characteristic can be used. Each of these properties serve
@@ skipping 15 matching lines @@
   AUTHENTICATED_SIGNED_WRITES = 64,
   EXTENDED_PROPERTIES = 128,
   RELIABLE_WRITE = 256,
   WRITABLE_AUXILIARIES = 512,
   READ_ENCRYPTED = 1024,
   WRITE_ENCRYPTED = 2048,
   READ_ENCRYPTED_AUTHENTICATED = 4096,
   WRITE_ENCRYPTED_AUTHENTICATED = 8192
 };
 
+// Values representing read, write, and encryption permissions for a
+// characteristic's value. While attribute permissions for all GATT
+// definitions have been set by the Bluetooth specification, characteristic
+// value permissions are left up to the higher-level profile.
+//
+// Attribute permissions are distinct from the characteristic properties. For
+// example, a characteristic may have the property |PROPERTY_READ| to make
+// clients know that it is possible to read the characteristic value and have
+// the permission |PERMISSION_READ_ENCRYPTED| to require a secure connection.
+// It is up to the application to properly specify the permissions and
+// properties for a local characteristic.
+// TODO(rkc): Currently BlueZ infers permissions for characteristics from
+// the properties. Once this is fixed, we will start sending the permissions
+// for characteristics to BlueZ. Till then permissions for characteristics
+// are unimplemented.
+enum Permission {
+  NONE = 0,
+  READ = 1,
+  WRITE = 2,
+  READ_ENCRYPTED = 4,
+  WRITE_ENCRYPTED = 8,
+  READ_ENCRYPTED_AUTHENTICATED = 16,
+  WRITE_ENCRYPTED_AUTHENTICATED = 32

[ortuno, 2017/01/20 03:45:22]

So sad that we have to manually write these... Are there any opened issues to
fix this?

[mbrunson, 2017/01/21 01:49:00]

There are no open issues for this. rockot has told me that the enum has to have
a defined IPC::ParamTraits to even begin the process for this feature. According
to the docs[1], you can only use the matching enum in C++, so JavaScript would
be a no-go.

[1]
https://www.chromium.org/developers/design-documents/mojo/type-mapping#TOC-Us...

[ortuno, 2017/01/22 22:38:00]

Ah I should have been more explicit. I'm sad that we have to manually write 0,
1, 2, 4, 8, etc. Are there any issues open that would simplify that?

[mbrunson, 2017/01/24 00:25:31]

I didn't find any open issues for this, so I made one: crbug.com/684168

+};
+
+enum GattResult {
+  SUCCESS,
+  UNKNOWN,
+  FAILED,
+  IN_PROGRESS,
+  INVALID_LENGTH,
+  NOT_PERMITTED,
+  NOT_AUTHORIZED,
+  NOT_PAIRED,
+  NOT_SUPPORTED
+};
+
 // TODO(crbug.com/657632): Remove when numerical values can be optional.
 struct RSSIWrapper {
   int8 value;
 };
 
 struct DeviceInfo {
   string? name;
   string name_for_display;
   string address;
   bool is_gatt_connected;
   RSSIWrapper? rssi;
 };
 
 struct ServiceInfo {
   string id;
   UUID uuid;
   bool is_primary;
 };
 
 struct CharacteristicInfo {
   string id;
   UUID uuid;
   uint32 properties;
+  uint32 permissions;
+  array<uint8> value;

[ortuno, 2017/01/20 03:45:22]

I would rename this to last_known_value.

[mbrunson, 2017/01/21 01:49:00]

Done.

 };
 
 interface Device {
   // Disconnects and deletes the Device.
   Disconnect();
 
   // Gets basic information about the device. Returns null, if no device is
   // available.
   GetInfo() => (DeviceInfo? info);
 
   // Gets the GATT Services in this device's GATT Server.
   GetServices() => (array<ServiceInfo> services);
 
   // Gets the GATT Characteristics in the GATT Service with |service_id|.
   GetCharacteristics(string service_id) =>
       (array<CharacteristicInfo> characteristics);
+
+  // Reads the value for the GATT Characteristic with |characteristic_id| in
+  // the GATT Service with |service_id|.
+  ReadValueForCharacteristic(string service_id, string characteristic_id) =>
+      (GattResult result, array<uint8> value);

[ortuno, 2017/01/20 03:45:22]

shouldn't value be optional?

[mbrunson, 2017/01/21 01:49:00]

Done.

+
+  // Writes the |value| to the GATT Characteristic with |characteristic_id| in
+  // the GATT Service with |service_id|.
+  WriteValueForCharacteristic(array<uint8> value, string service_id,

[ortuno, 2017/01/20 03:45:22]

optional: put value at the end.

[mbrunson, 2017/01/21 01:49:00]

Done.

+      string characteristic_id) => (GattResult result);
 };