Added safeguards to not synchronously write or read when using asynchronous api and viceversa

usbserial/src/main/java/com/felhr/usbserial/CDCSerialDevice.java

@@ -74,6 +74,8 @@ public class CDCSerialDevice extends UsbSerialDevice
             // Pass references to the threads
             setThreadsParams(requestIN, outEndpoint);
 
+            asyncMode = true;
+
             return true;
         }else
         {
@@ -98,6 +100,7 @@ public class CDCSerialDevice extends UsbSerialDevice
         if(ret)
         {
             setSyncParams(inEndpoint, outEndpoint);
+            asyncMode = false;
             return true;
         }else
         {

usbserial/src/main/java/com/felhr/usbserial/CH34xSerialDevice.java

@@ -84,6 +84,8 @@ public class CH34xSerialDevice extends UsbSerialDevice
             // Pass references to the threads
             setThreadsParams(requestIN, outEndpoint);
 
+            asyncMode = true;
+
             return true;
         }else
         {
@@ -107,6 +109,7 @@ public class CH34xSerialDevice extends UsbSerialDevice
         {
             setBaudRate(DEFAULT_BAUDRATE);
             setSyncParams(inEndpoint, outEndpoint);
+            asyncMode = false;
             return true;
         }else
         {

usbserial/src/main/java/com/felhr/usbserial/CP2102SerialDevice.java

@@ -108,6 +108,8 @@ public class CP2102SerialDevice extends UsbSerialDevice
             // Pass references to the threads
             setThreadsParams(requestIN, outEndpoint);
 
+            asyncMode = true;
+
             return true;
         }else
         {
@@ -134,6 +136,7 @@ public class CP2102SerialDevice extends UsbSerialDevice
             // Create Flow control thread but it will only be started if necessary
             createFlowControlThread();
             setSyncParams(inEndpoint, outEndpoint);
+            asyncMode = false;
             return true;
         }else
         {

usbserial/src/main/java/com/felhr/usbserial/FTDISerialDevice.java

@@ -120,6 +120,8 @@ public class FTDISerialDevice extends UsbSerialDevice
             // Pass references to the threads
             setThreadsParams(requestIN, outEndpoint);
 
+            asyncMode = true;
+
             return true;
         }else
         {
@@ -145,6 +147,7 @@ public class FTDISerialDevice extends UsbSerialDevice
         if(ret)
         {
             setSyncParams(inEndpoint, outEndpoint);
+            asyncMode = false;
             return true;
         }else
         {

usbserial/src/main/java/com/felhr/usbserial/PL2303SerialDevice.java

@@ -72,6 +72,8 @@ public class PL2303SerialDevice extends UsbSerialDevice
             // Pass references to the threads
             setThreadsParams(requestIN, outEndpoint);
 
+            asyncMode = true;
+
             return true;
         }else
         {
@@ -94,6 +96,7 @@ public class PL2303SerialDevice extends UsbSerialDevice
         if(ret)
         {
             setSyncParams(inEndpoint, outEndpoint);
+            asyncMode = false;
             return true;
         }else
         {

usbserial/src/main/java/com/felhr/usbserial/UsbSerialDevice.java

@@ -34,6 +34,8 @@ public abstract class UsbSerialDevice implements UsbSerialInterface
     private UsbEndpoint inEndpoint;
     private UsbEndpoint outEndpoint;
 
+    protected boolean asyncMode;
+
     // Get Android version if version < 4.3 It is not going to be asynchronous read operations
     static
     {
@@ -47,6 +49,7 @@ public abstract class UsbSerialDevice implements UsbSerialInterface
     {
         this.device = device;
         this.connection = connection;
+        this.asyncMode = true;
         serialBuffer = new SerialBuffer(mr1Version);
     }
 
@@ -86,30 +89,16 @@ public abstract class UsbSerialDevice implements UsbSerialInterface
     @Override
     public void write(byte[] buffer)
     {
-        serialBuffer.putWriteBuffer(buffer);
-    }
-
-    // Common Usb Serial Operations (I/O Synchronous)
-    @Override
-    public int syncWrite(byte[] buffer, int timeout)
-    {
-        if(buffer == null)
-            return 0;
-
-        return connection.bulkTransfer(outEndpoint, buffer, buffer.length, timeout);
-    }
-
-    @Override
-    public int syncRead(byte[] buffer, int timeout)
-    {
-        if(buffer == null)
-            return 0;
-        return connection.bulkTransfer(inEndpoint, buffer, buffer.length, timeout);
+        if(asyncMode)
+            serialBuffer.putWriteBuffer(buffer);
     }
 
     @Override
     public int read(UsbReadCallback mCallback)
     {
+        if(!asyncMode)
+            return -1;
+
         if(mr1Version)
         {
             workerThread.setCallback(mCallback);
@@ -126,6 +115,42 @@ public abstract class UsbSerialDevice implements UsbSerialInterface
     @Override
     public abstract void close();
 
+    // Common Usb Serial Operations (I/O Synchronous)
+    @Override
+    public abstract boolean syncOpen();
+
+    @Override
+    public abstract void syncClose();
+
+    @Override
+    public int syncWrite(byte[] buffer, int timeout)
+    {
+        if(!asyncMode)
+        {
+            if(buffer == null)
+                return 0;
+
+            return connection.bulkTransfer(outEndpoint, buffer, buffer.length, timeout);
+        }else
+        {
+            return -1;
+        }
+    }
+
+    @Override
+    public int syncRead(byte[] buffer, int timeout)
+    {
+        if(!asyncMode)
+        {
+            if(buffer == null)
+                return 0;
+            return connection.bulkTransfer(inEndpoint, buffer, buffer.length, timeout);
+        }else
+        {
+            return -1;
+        }
+    }
+
     // Serial port configuration
     @Override
     public abstract void setBaudRate(int baudRate);