Merge pull request #3 from elafargue/master

Implement reading from the serial port. Better error checking

Author: xseignard

README.md

@@ -2,7 +2,14 @@
 
 Cordovarduino is a Cordova/Phonegap plugin that enable you to use serial communication from an Android device to a serial over USB capable one.
 
-It's a **work in progress** : Android to Arduino works, Arduino to Android is not yet supported
+It's a **work in progress** : Android to Arduino works, Arduino to Android now works.
+
+
+## Change log
+
+2014.03: Ed. Lafargue
+         Implemented read(). The success callback returns a Javascript ArrayBuffer which is the best way to handle binary data
+         in Javascript. It is straightforward to convert this to a string if required - a utility function could be implemented in this plugin.
 
 ### Context
 This work was made during an art residency hosted at the [Stereolux, Laboratoire Arts et Technologies](http://www.stereolux.org/laboratoire-arts-et-technologies) with [Coup de foudre](https://www.facebook.com/coup.defoudre.716) and [Xavier Seignard](http://drangies.fr).
@@ -37,9 +44,10 @@ serial.open(opts, function success(), function error());
 You're now able to read and write:
 ```js
 serial.write(data, function success(), function error());
-serial.read(function success(), function error());
+serial.read(function success(buffer), function error());
 ```
 `data` is the string representation to be written to the serial port.
+`buffer` is a JavaScript ArrayBuffer containing the data that was just read.
 
 And finally close the port:
 ```js

lib/usbseriallibrary.jar

@@ -1,9 +1,11 @@
 package org.stereolux.cordova.serial;
 
 import java.io.IOException;
+import java.nio.ByteBuffer;
 import java.util.List;
 
 import org.apache.cordova.CallbackContext;
+import org.apache.cordova.PluginResult;
 import org.apache.cordova.CordovaPlugin;
 import org.json.JSONArray;
 import org.json.JSONException;
@@ -21,6 +23,7 @@
 import com.hoho.android.usbserial.driver.UsbSerialDriver;
 import com.hoho.android.usbserial.driver.UsbSerialPort;
 import com.hoho.android.usbserial.driver.UsbSerialProber;
+import com.hoho.android.usbserial.util.SerialInputOutputManager.Listener;
 
 /**
  * Cordova plugin to communicate with the android serial port
@@ -42,6 +45,12 @@ public class Serial extends CordovaPlugin {
     // The serial port that will be used in this plugin
     private UsbSerialPort port;
 
+    private static final int READ_WAIT_MILLIS = 200;
+    private static final int BUFSIZ = 4096;
+
+    private final ByteBuffer mReadBuffer = ByteBuffer.allocate(BUFSIZ);
+    private final ByteBuffer mWriteBuffer = ByteBuffer.allocate(BUFSIZ);
+        
     /**
      * Overridden execute method
      * @param action the string representation of the action to execute
@@ -170,8 +179,11 @@ public void run() {
     private void writeSerial(final String data, final CallbackContext callbackContext) {
         cordova.getThreadPool().execute(new Runnable() {
             public void run() {
-                Log.d(TAG, data);
+            	if (port == null) {
+            		callbackContext.error("writing a closed port");
+            	} else
                 try {
+                    Log.d(TAG, data);
                     byte[] buffer = data.getBytes();
                     port.write(buffer, 1000);
                     callbackContext.success();
@@ -191,10 +203,24 @@ public void run() {
     private void readSerial(final CallbackContext callbackContext) {
         cordova.getThreadPool().execute(new Runnable() {
             public void run() {
+            	if (port == null) {
+            		callbackContext.error("reading a closed port");
+            	} else
                 try {
-                    byte buffer[] = new byte[16];
-                    int numBytesRead = port.read(buffer, 1000);
-                    callbackContext.success(numBytesRead);
+                    int len = port.read(mReadBuffer.array(), READ_WAIT_MILLIS);
+                    // Whatever happens, we send an "OK" result, up to the
+                    // receiver to check that len > 0
+                    PluginResult.Status status = PluginResult.Status.OK;
+                    if (len > 0) {
+                        Log.d(TAG, "Read data len=" + len);
+                        final byte[] data = new byte[len];
+                        mReadBuffer.get(data, 0, len);
+                        mReadBuffer.clear();
+                        callbackContext.sendPluginResult(new PluginResult(status,data));
+                	} else {
+                		final byte[] data = new byte[0];
+                		callbackContext.sendPluginResult(new PluginResult(status, data));
+                	}
                 }
                 catch (IOException e) {
                     // deal with error
@@ -213,7 +239,10 @@ private void closeSerial(final CallbackContext callbackContext) {
         cordova.getThreadPool().execute(new Runnable() {
             public void run() {
                 try {
-                    port.close();
+                	// Make sure we don't die if we try to close an non-existing port!
+                	if (port != null)
+                		port.close();
+                	port = null;
                     callbackContext.success();
                 } catch (IOException e) {
                     // deal with error