more configurable debug log, disabled by default (#389)

usbSerialForAndroid/src/androidTest/java/com/hoho/android/usbserial/util/UsbWrapper.java

@@ -12,6 +12,7 @@ import android.net.Uri;
 import android.util.Log;
 
 import com.hoho.android.usbserial.driver.CdcAcmSerialDriver;
+import com.hoho.android.usbserial.driver.CommonUsbSerialPort;
 import com.hoho.android.usbserial.driver.UsbSerialDriver;
 import com.hoho.android.usbserial.driver.UsbSerialPort;
 
@@ -53,6 +54,7 @@ public class UsbWrapper implements SerialInputOutputManager.Listener {
         this.serialDriver = serialDriver;
         this.devicePort = devicePort;
         serialPort = serialDriver.getPorts().get(devicePort);
+        CommonUsbSerialPort.DEBUG = true;
     }
 
     public void setUp() throws Exception {

usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/CommonUsbSerialPort.java

@@ -26,6 +26,7 @@ import java.util.EnumSet;
 public abstract class CommonUsbSerialPort implements UsbSerialPort {
 
     private static final String TAG = CommonUsbSerialPort.class.getSimpleName();
+    public static boolean DEBUG = false;
     private static final int DEFAULT_WRITE_BUFFER_SIZE = 16 * 1024;
     private static final int MAX_READ_SIZE = 16 * 1024; // = old bulkTransfer limit
 
@@ -238,7 +239,9 @@ public abstract class CommonUsbSerialPort implements UsbSerialPort {
                     actualLength = mConnection.bulkTransfer(mWriteEndpoint, writeBuffer, requestLength, requestTimeout);
                 }
             }
-            Log.d(TAG, "Wrote " + actualLength + "/" + requestLength + " offset " + offset + "/" + src.length + " timeout " + requestTimeout);
+            if (DEBUG) {
+                Log.d(TAG, "Wrote " + actualLength + "/" + requestLength + " offset " + offset + "/" + src.length + " timeout " + requestTimeout);
+            }
             if (actualLength <= 0) {
                 if (timeout != 0 && MonotonicClock.millis() >= endTime) {
                     SerialTimeoutException ex = new SerialTimeoutException("Error writing " + requestLength + " bytes at offset " + offset + " of total " + src.length + ", rc=" + actualLength);

usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/util/SerialInputOutputManager.java

@@ -223,7 +223,9 @@ public class SerialInputOutputManager implements Runnable {
         }
         int len = mSerialPort.read(buffer, mReadTimeout);
         if (len > 0) {
-            if (DEBUG) Log.d(TAG, "Read data len=" + len);
+            if (DEBUG) {
+                Log.d(TAG, "Read data len=" + len);
+            }
             final Listener listener = getListener();
             if (listener != null) {
                 final byte[] data = new byte[len];