/*
* Copyright 2010-2011 Research In Motion Limited.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package blackberry.io.file;
import java.io.DataInputStream;
import java.io.IOException;
import net.rim.device.api.script.ScriptableFunction;
import blackberry.core.FunctionSignature;
import blackberry.core.ScriptableFunctionBase;
import blackberry.core.WidgetBlob;
import blackberry.io.FileConnectionWrapper;
/**
* JavaScript function class - reads a file and returns a JS callback to allow
* users to retrieve the data
*/
public final class ReadFileFunction extends ScriptableFunctionBase {
public static final String NAME = "readFile";
/**
* Read a given file and call the callback function after finishing reading.
* The size of the file cannot exceed 2147483647 bytes (Max value of int).
* The JavaScript callback function will be provided two parameters. The
* first is a string representing the full path of the file. The second is
* the Blob that contains the contents of the file opened.
*
* @param args
* args[0]: A complete URL path to a file args[1]: A call back
* function (ScriptableFunction) args[2]: true if read should be
* asynchronous, false otherwise
*
* IOException will be thrown if 1. src file does not yet exist,
* or the src path is to an directory; if reading is asynchronous,
* no exceptions will be thrown when an error occurs
*/
public Object execute( Object thiz, Object[] args ) throws Exception {
FileConnectionWrapper fConnWrap = new FileConnectionWrapper( args[ 0 ].toString() );
fConnWrap.openDataInputStream();
if( args.length == 2 || ( args.length == 3 && ( (Boolean) args[ 2 ] ).booleanValue() ) ) { // Async read
new Thread( new AsyncRead( this, fConnWrap, args[ 0 ].toString(), (ScriptableFunction) args[ 1 ] ) ).start();
} else { // Sync read
read( this, fConnWrap, args[ 0 ].toString(), (ScriptableFunction) args[ 1 ] );
}
return UNDEFINED;
}
private void read( Object thiz, FileConnectionWrapper fConnWrap, String path,
ScriptableFunction func ) throws Exception {
try {
DataInputStream dis = fConnWrap.getDataInputStream();
int size = (int) fConnWrap.getFileConnection().fileSize();
byte[] data = new byte[ size ];
int numBytesRead;
try {
numBytesRead = dis.read( data, 0, size );
} catch ( IOException ioe ) {
throw new Exception( "Exception reading file" );
}
if( numBytesRead != size ) {
throw new Exception( "File size does not match number of bytes read." );
}
Object[] args = new Object[ 2 ];
args[ 0 ] = path;
args[ 1 ] = new WidgetBlob( data );
func.invoke( thiz, args );
} finally {
if( fConnWrap != null ) {
fConnWrap.close();
}
}
}
/**
* @see blackberry.core.ScriptableFunctionBase#getFunctionSignatures
*/
protected FunctionSignature[] getFunctionSignatures() {
FunctionSignature fs = new FunctionSignature( 3 );
fs.addParam( String.class, true );
fs.addParam( ScriptableFunction.class, true );
fs.addParam( Boolean.class, false );
return new FunctionSignature[] { fs };
}
/**
* Class provides async read functionality
*/
private class AsyncRead implements Runnable {
private FileConnectionWrapper _fConnWrap;
private Object _thiz;
private String _path;
private ScriptableFunction _callBackFunc;
/**
* Constructor
*
* @param thiz
* @param fConnWrap
* @param path
* @param func
*/
public AsyncRead( Object thiz, FileConnectionWrapper fConnWrap, String path,
ScriptableFunction func ) {
_thiz = thiz;
_fConnWrap = fConnWrap;
_path = path;
_callBackFunc = func;
}
/**
* @see Runnable#run
*/
public void run() {
try {
read( _thiz, _fConnWrap, _path, _callBackFunc );
} catch( Exception ignore ) {
}
}
}
}