Use Kernel BlueZ Manager for Discovery, Connect, etc. (Initial Commit - Java part probably broken)

We have experienced the following using the official HCI communication channel:
- Lower connect performance with discovery enabled
- Instability with enabled discovery and breaking general BT adapter state
  requiring a 'hciconfig hci0 reset'
- Lack of notifications: start/stop discovery/connect/...
- Lack of certain settings in general: pin, ..

This commit implements discovery including listening to all BlueZ kernel events
from the BlueZ Manager channel using DBTManager.
TODO: Figure out how to enforce quick connect!

- EInfoReport (EIR) added: FLAGS, DEVICE_CLASS, APPEARANCE, HASH, RANDOMIZER and DEVICE_ID
  - including parsing new segments in read_data(..) and dataSetToString(..) exposure

- DBTManager adds:

  - manager-reader thread, putting all command status/completes to its ringbuffer
    and sending out all other events to its listener.

  - Respecting the chosen BTMode (side-effect to discovery etc)

  - add: start/stop discovery

  - add: connect/disconnect (incomplete)

- DBTAdapter:
  - discoverDevices -> discoverDevicesMgmt is becoming redundant,
    now simply waiting for the DeviceFound event.
    Will be deleted - TODO!

  - mgmtEvDeviceFoundCB shall perform remaining EIR parsing
    and enqueing the devices plus issuing respective discovery callbacks!
    TODO.

- DBTDevice adds:
  - BDAddressType

- HCISession's HCIComm is now no more used (to be deleted!)

- HCIComm adds generic read/write methods, mutex free.
  - Remaining HCI 'managment' methods are also subject to deletion!

- GATTHandler / DBTManager: only use a mtx_write for communication,
  as reading is performed on their respective threads using a ringbuffer.
  Here only concurrent write access needs to be managed.
  (DBTManager uses its own HCIComm's mutex.)

- MgmtTypes adds:

  - BTMode for dual, BREDR or LE only.

  - MgmtRequest -> MgmtCommand

  - Unifies the command opcodes to global 'MgmtOpcode',
    removing duplicate MgmtCommand::Opcode (which was also incomplete)

  - Adding MgmtDisconnectCmd, MgmtEvtDiscovering, MgmtEvtDeviceFound
           MgmtEvtDeviceConnected, MgmtEvtDeviceDisconnected

- TOctets adding get_int8(..) and get_eui48(..)
- TOctets adding put_eui48(..)

++++++++++++++

New ClassFunction: Introducing versatile C++ function-method type
used for our DBTManager callbacks.
In contrast to std::function and std::bind, ClassFunction allows
using its specific type (return- and argument types)
and offering the equality operation to test its identity.
The latter is essential to remove a callback ClassFunction
from a list of callbacks.

+++++++++++++++++

Further code cleanup is also included

- Address_T -> BDAddressType(incl string presentation) + HCIAddressType

- ManufactureSpecificData using POctets

- Convenient default param: uint*HexString(.., const bool leading0X=true);

- MgmtTypes's get/put for events and commands use MGMT_HEADER_SIZE offset

- MgmtTypes: Remove doubled 'btohs', as the pdu.get* commands
  already perform endian conversion.

- EInfoReport::read_data(..) validate segment size before type conversion

1 files changed, 12 insertions, 6 deletions

diff --git a/api/direct_bt/BTAddress.hpp b/api/direct_bt/BTAddress.hpp
index 4fd6807d..01bc4fa1 100644
--- a/api/direct_bt/BTAddress.hpp
+++ b/api/direct_bt/BTAddress.hpp
@@ -93,17 +93,23 @@ namespace direct_bt {
      *
      * +++
      *
-     * Couldn't yet find a reference to the L2CAP Address Type, which differs from HCI Address Type!
+     * Couldn't yet find a reference to the BDADDR/L2CAP Address Type, which differs from HCI Address Type!
      */
-    enum Address_T : uint8_t {
+    enum BDAddressType : uint8_t {
+        BDADDR_BREDR      = 0x00,
+        BDADDR_LE_PUBLIC  = 0x01,
+        BDADDR_LE_RANDOM  = 0x02,
+        BDADDR_UNDEFINED  = 0xff
+    };
+
+    enum HCIAddressType : uint8_t {
         HCIADDR_LE_PUBLIC = 0x00,
         HCIADDR_LE_RANDOM = 0x01,
-
-        L2CAPADDR_BREDR      = 0x00,
-        L2CAPADDR_LE_PUBLIC  = 0x01,
-        L2CAPADDR_LE_RANDOM  = 0x02
+        HCIADDR_UNDEFINED = 0xff
     };
 
+    std::string getBDAddressTypeString(const BDAddressType op);
+
 } // namespace direct_bt
 
 #endif /* BT_ADDRESS_HPP_ */