adapter: Added support to open multiple time the same adapter

common/gattlib_common_adapter.c

@@ -10,6 +10,38 @@
 // It could happen when using Python wrapper.
 GSList *m_adapter_list;
 
+static int stricmp(char const *a, char const *b) {
+    for (;; a++, b++) {
+        int d = tolower((unsigned char)*a) - tolower((unsigned char)*b);
+        if (d != 0 || !*a)
+            return d;
+    }
+}
+
+static gint _is_adapter_id(gconstpointer a, gconstpointer b) {
+	const gattlib_adapter_t* adapter = a;
+	const char* adapter_id = b;
+
+	return stricmp(adapter->id, adapter_id);
+}
+
+gattlib_adapter_t* gattlib_adapter_from_id(const char* adapter_id) {
+	gattlib_adapter_t* adapter = NULL;
+
+	g_rec_mutex_lock(&m_gattlib_mutex);
+
+	GSList *adapter_entry = g_slist_find_custom(m_adapter_list, adapter_id, _is_adapter_id);
+	if (adapter_entry == NULL) {
+		goto EXIT;
+	}
+
+	adapter = adapter_entry->data;
+
+EXIT:
+	g_rec_mutex_unlock(&m_gattlib_mutex);
+	return adapter;
+}
+
 bool gattlib_adapter_is_valid(gattlib_adapter_t* adapter) {
 	bool is_valid;
 

common/gattlib_internal.h

@@ -68,6 +68,9 @@ struct _gattlib_adapter {
 	// Context specific to the backend implementation (eg: dbus backend)
 	struct _gattlib_adapter_backend backend;
 
+	// BLE adapter id (could be its DBUS device path on Linux)
+	char* id;
+
 	// BLE adapter name
 	char* name;
 
@@ -121,6 +124,7 @@ extern GSList *m_adapter_list;
 // This structure is used for inter-thread communication
 extern struct gattlib_signal m_gattlib_signal;
 
+gattlib_adapter_t* gattlib_adapter_from_id(const char* adapter_id);
 bool gattlib_adapter_is_valid(gattlib_adapter_t* adapter);
 bool gattlib_adapter_is_scanning(gattlib_adapter_t* adapter);
 int gattlib_adapter_ref(gattlib_adapter_t* adapter);

dbus/gattlib_adapter.c

@@ -28,10 +28,21 @@ int gattlib_adapter_open(const char* adapter_name, gattlib_adapter_t** adapter)
 		adapter_name = GATTLIB_DEFAULT_ADAPTER;
 	}
 
-	GATTLIB_LOG(GATTLIB_DEBUG, "Open bluetooth adapter %s", adapter_name);
-
 	snprintf(object_path, sizeof(object_path), "/org/bluez/%s", adapter_name);
 
+	// Check if adapter has already be loaded
+	g_rec_mutex_lock(&m_gattlib_mutex);
+	*adapter = gattlib_adapter_from_id(object_path);
+	if (*adapter != NULL) {
+		GATTLIB_LOG(GATTLIB_DEBUG, "Bluetooth adapter %s has already been opened. Re-use it", adapter_name);
+		gattlib_adapter_ref(*adapter);
+		g_rec_mutex_unlock(&m_gattlib_mutex);
+		return GATTLIB_SUCCESS;
+	}
+	g_rec_mutex_unlock(&m_gattlib_mutex);
+
+	GATTLIB_LOG(GATTLIB_DEBUG, "Open bluetooth adapter %s", adapter_name);
+
 	adapter_proxy = org_bluez_adapter1_proxy_new_for_bus_sync(
 			G_BUS_TYPE_SYSTEM, G_DBUS_PROXY_FLAGS_NONE,
 			"org.bluez",
@@ -58,6 +69,7 @@ int gattlib_adapter_open(const char* adapter_name, gattlib_adapter_t** adapter)
 	}
 
 	// Initialize stucture
+	gattlib_adapter->id = strdup(object_path);
 	gattlib_adapter->name = strdup(adapter_name);
 	gattlib_adapter->reference_counter = 1;
 	gattlib_adapter->backend.adapter_proxy = adapter_proxy;
@@ -651,11 +663,6 @@ int gattlib_adapter_close(gattlib_adapter_t* adapter) {
 	bool are_devices_disconnected;
 	int ret = GATTLIB_SUCCESS;
 
-	//
-	// TODO: Should we use reference counting to be able to open multiple times an adapter
-	//       without freeing it on the first gattlib_adapter_close()
-	//
-
     g_rec_mutex_lock(&m_gattlib_mutex);
 
 	if (!gattlib_adapter_is_valid(adapter)) {
@@ -689,9 +696,6 @@ int gattlib_adapter_close(gattlib_adapter_t* adapter) {
 	// Unref/Free the adapter
 	gattlib_adapter_unref(adapter);
 
-	// Remove adapter from the global list
-	m_adapter_list = g_slist_remove(m_adapter_list, adapter);
-
 EXIT:
 	g_rec_mutex_unlock(&m_gattlib_mutex);
 	return ret;
@@ -730,6 +734,11 @@ int gattlib_adapter_unref(gattlib_adapter_t* adapter) {
 		adapter->backend.adapter_proxy = NULL;
 	}
 
+	if (adapter->id != NULL) {
+		free(adapter->id);
+		adapter->id = NULL;
+	}
+
 	if (adapter->name != NULL) {
 		free(adapter->name);
 		adapter->name = NULL;
@@ -737,6 +746,9 @@ int gattlib_adapter_unref(gattlib_adapter_t* adapter) {
 
 	gattlib_devices_free(adapter);
 
+	// Remove adapter from the global list
+	m_adapter_list = g_slist_remove(m_adapter_list, adapter);
+
 	free(adapter);
 
 EXIT: