Bluetooth (Linux): improve performance when showDisconnected == false

If no connected devices found, no dbus calls will be emitted

Fix #1450

src/detection/bluetooth/bluetooth.h

@@ -11,4 +11,4 @@ typedef struct FFBluetoothResult
     bool connected;
 } FFBluetoothResult;
 
-const char* ffDetectBluetooth(FFlist* devices /* FFBluetoothResult */);
+const char* ffDetectBluetooth(FFBluetoothOptions* options, FFlist* devices /* FFBluetoothResult */);

src/detection/bluetooth/bluetooth_apple.m

@@ -10,7 +10,7 @@
     @property (nonatomic) uint8_t batteryPercentSingle;
 @end
 
-const char* ffDetectBluetooth(FFlist* devices /* FFBluetoothResult */)
+const char* ffDetectBluetooth(FFBluetoothOptions* options, FFlist* devices /* FFBluetoothResult */)
 {
     NSArray<IOBluetoothDevice*>* ioDevices = IOBluetoothDevice.pairedDevices;
     if(!ioDevices)

src/detection/bluetooth/bluetooth_linux.c

@@ -3,6 +3,7 @@
 
 #ifdef FF_HAVE_DBUS
 #include "common/dbus.h"
+#include "common/io/io.h"
 
 /* Example dbus reply, striped to only the relevant parts:
 array [                                                     //root
@@ -192,11 +193,30 @@ static const char* detectBluetooth(FFlist* devices)
     return NULL;
 }
 
+static bool hasConnectedDevices(void)
+{
+    FF_AUTO_CLOSE_DIR DIR* dirp = opendir("/sys/class/bluetooth");
+    if(dirp == NULL)
+        return false;
+
+    struct dirent* entry;
+    while ((entry = readdir(dirp)) != NULL)
+    {
+        if (strchr(entry->d_name, ':') != NULL) // ignore connected devices
+            return true;
+    }
+
+    return false;
+}
+
 #endif
 
-const char* ffDetectBluetooth(FF_MAYBE_UNUSED FFlist* devices /* FFBluetoothResult */)
+const char* ffDetectBluetooth(FFBluetoothOptions* options, FF_MAYBE_UNUSED FFlist* devices /* FFBluetoothResult */)
 {
     #ifdef FF_HAVE_DBUS
+        if (!options->showDisconnected && !hasConnectedDevices())
+            return NULL;
+
         return detectBluetooth(devices);
     #else
         return "Fastfetch was compiled without DBus support";

src/detection/bluetooth/bluetooth_nosupport.c

@@ -1,6 +1,6 @@
 #include "bluetooth.h"
 
-const char* ffDetectBluetooth(FF_MAYBE_UNUSED FFlist* devices /* FFBluetoothResult */)
+const char* ffDetectBluetooth(FF_MAYBE_UNUSED FFBluetoothOptions* options, FF_MAYBE_UNUSED FFlist* devices /* FFBluetoothResult */)
 {
     return "Not supported on this platform";
 }

src/detection/bluetooth/bluetooth_windows.c

@@ -7,7 +7,7 @@
 
 #pragma GCC diagnostic ignored "-Wpointer-sign"
 
-const char* ffDetectBluetooth(FFlist* devices /* FFBluetoothResult */)
+const char* ffDetectBluetooth(FFBluetoothOptions* options, FFlist* devices /* FFBluetoothResult */)
 {
     // Actually bluetoothapis.dll, but it's missing on Windows 7
     FF_LIBRARY_LOAD(bluetoothapis, "dlopen bthprops.cpl failed", "bthprops.cpl", 1)