Open [& Connect] @ ctor (RAII): HCIComm, L2CAPComm, GATTHandler, simplifying 'connect' lifecycle

Further:
- L2CAPComm
-- disconnect(): Only lock mtw_write if connected and mark noexcept
-- Added '~L2CAPComm() noexcept' for RAII
-- Removed unsued accessors

- GATTHandler
-- Similar treatment as L2CAPComm

- DBTDevice
-- Remove mtx_gatt and its locks, they were not consistent.
   Rely on mtx_connect (connectGATT/getGATTServices/disconnect)
   and atomic local GATTHandler copy when using.

-- disconnect GATTHandler directly in disconnect, remove explicit method.

-- pingGATT uses local gattHandler copy to avoid parallel disconnect nullptr,
   however, it will fail immediately due to disconnection.

1 files changed, 10 insertions, 10 deletions

diff --git a/api/direct_bt/GATTHandler.hpp b/api/direct_bt/GATTHandler.hpp
index 829deec2..246732ad 100644
--- a/api/direct_bt/GATTHandler.hpp
+++ b/api/direct_bt/GATTHandler.hpp
@@ -203,21 +203,23 @@ namespace direct_bt {
             uint16_t exchangeMTU(const uint16_t clientMaxMTU);
 
         public:
+            /**
+             * Constructing a new GATTHandler instance with its opened and connected L2CAP channel.
+             * <p>
+             * After successful l2cap connection, the MTU will be exchanged.
+             * See getServerMTU() and getUsedMTU(), the latter is in use.
+             * </p>
+             */
             GATTHandler(const std::shared_ptr<DBTDevice> & device) noexcept;
 
-            ~GATTHandler();
+            /** Destructor closing this instance including L2CAP channel, see {@link #disconnect()}. */
+            ~GATTHandler() noexcept;
 
-            bool getIsConnected() const noexcept { return isConnected; }
+            bool getIsConnected() const noexcept { return isConnected ; }
             bool getHasIOError() const noexcept { return hasIOError; }
             std::string getStateString() const noexcept { return L2CAPComm::getStateString(isConnected, hasIOError); }
 
             /**
-             * After successful l2cap connection, the MTU will be exchanged.
-             * See getServerMTU() and getUsedMTU(), the latter is in use.
-             */
-            bool connect() noexcept;
-
-            /**
              * Disconnect this GATTHandler and optionally the associated device
              * @param disconnectDevice if true, associated device will also be disconnected, otherwise not.
              * @param ioErrorCause if true, reason for disconnection is an IO error
@@ -225,8 +227,6 @@ namespace direct_bt {
              */
             bool disconnect(const bool disconnectDevice, const bool ioErrorCause) noexcept;
 
-            bool isOpen() const noexcept { return isConnected && l2cap.isOpen(); }
-
             inline uint16_t getServerMTU() const noexcept { return serverMTU; }
             inline uint16_t getUsedMTU()  const noexcept { return usedMTU; }