DBTManager, HCIHandler, GATTHandler: Defer fetching timeout+ config from environment until instance creation using singleton holder

Otherwise static initialization at library load will occur
and hence not allow the Java BluetoothFactory to pass the properties to the environment before.

1 files changed, 38 insertions, 12 deletions

diff --git a/api/direct_bt/GATTHandler.hpp b/api/direct_bt/GATTHandler.hpp
index 7ebb2106..57b65c8d 100644
--- a/api/direct_bt/GATTHandler.hpp
+++ b/api/direct_bt/GATTHandler.hpp
@@ -57,6 +57,43 @@ namespace direct_bt {
     class DBTDevice; // forward
 
     /**
+     * GATT Singleton runtime environment properties
+     */
+    class GATTEnv {
+        private:
+            GATTEnv();
+
+        public:
+            /** L2CAP poll timeout for reader thread, defaults to 10s. */
+            static const int32_t L2CAP_READER_THREAD_POLL_TIMEOUT;
+            /** Timeout for GATT read command replies, defaults to 500ms. */
+            static const int32_t GATT_READ_COMMAND_REPLY_TIMEOUT;
+            /** Timeout for GATT write command replies, defaults to 500ms. */
+            static const int32_t GATT_WRITE_COMMAND_REPLY_TIMEOUT;
+            /** Timeout for l2cap _initial_ command reply, defaults to 2500ms. */
+            static const int32_t GATT_INITIAL_COMMAND_REPLY_TIMEOUT;
+
+            /** Medium ringbuffer capacity, defaults to 128 messages. */
+            static const int32_t ATTPDU_RING_CAPACITY;
+
+        public:
+            static GATTEnv& get() {
+                /**
+                 * Thread safe starting with C++11 6.7:
+                 *
+                 * If control enters the declaration concurrently while the variable is being initialized,
+                 * the concurrent execution shall wait for completion of the initialization.
+                 *
+                 * (Magic Statics)
+                 *
+                 * Avoiding non-working double checked locking.
+                 */
+                static GATTEnv e;
+                return e;
+            }
+    };
+
+    /**
      * A thread safe GATT handler associated to one device via one L2CAP connection.
      * <p>
      * Implementation utilizes a lock free ringbuffer receiving data within its separate thread.
@@ -79,19 +116,8 @@ namespace direct_bt {
             };
             static inline int number(const Defaults d) { return static_cast<int>(d); }
 
-            /** L2CAP poll timeout for reader thread, defaults to 10s. */
-            static const int32_t L2CAP_READER_THREAD_POLL_TIMEOUT;
-            /** Timeout for GATT read command replies, defaults to 500ms. */
-            static const int32_t GATT_READ_COMMAND_REPLY_TIMEOUT;
-            /** Timeout for GATT write command replies, defaults to 500ms. */
-            static const int32_t GATT_WRITE_COMMAND_REPLY_TIMEOUT;
-            /** Timeout for l2cap _initial_ command reply, defaults to 2500ms. */
-            static const int32_t GATT_INITIAL_COMMAND_REPLY_TIMEOUT;
-
-            /** Medium ringbuffer capacity, defaults to 128 messages. */
-            static const int32_t ATTPDU_RING_CAPACITY;
-
        private:
+            const GATTEnv & env;
             const bool debug_data;
 
             /** GATTHandle's device weak back-reference */