1 /*

     2 * Copyright (c) 2007 Nokia Corporation and/or its subsidiary(-ies). 

     3 * All rights reserved.

     4 * This component and the accompanying materials are made available

     5 * under the terms of "Eclipse Public License v1.0"

     6 * which accompanies this distribution, and is available

     7 * at the URL "http://www.eclipse.org/legal/epl-v10.html".

     8 *

     9 * Initial Contributors:

    10 * Nokia Corporation - initial contribution.

    11 *

    12 * Contributors:

    13 *

    14 * Description:  File Reader for DTD Files. Filters out UTF-8 and 16 byte order

    15  *                marks.

    16  *

    17 */

    18 

    19 

    20 package com.nokia.tools.themeinstaller.xmlparser;

    21 

    22 import java.io.ByteArrayInputStream;

    23 import java.io.File;

    24 import java.io.FileInputStream;

    25 import java.io.FileNotFoundException;

    26 import java.io.FileReader;

    27 import java.io.IOException;

    28 import java.io.Reader;

    29 import java.util.Arrays;

    30 

    31 import org.xml.sax.InputSource;

    32 

    33 import com.nokia.tools.themeinstaller.installationmanager.InstallationManager;

    34 

    35 /**

    36  * File Reader for DTD Files. Filters out UTF-8 and 16 byte order marks. Byte

    37  * order marks need to be filtered because FileReader can not tolerate BOMs.

    38  */

    39 public class DTDInputSource extends InputSource {

    40 

    41 	// CONSTANTS

    42 	private final static int BUFFER_LENGTH = 3;

    43 	private final static byte[] BOM_UTF8 = { (byte) 0xEF, (byte) 0xBB,

    44 			(byte) 0xBF };

    45 	private final static byte[] BOM_UTF16_BIG = { (byte) 0xFE, (byte) 0xFF };

    46 	private final static byte[] BOM_UTF16_LIT = { (byte) 0xFF, (byte) 0xFE };

    47 

    48 	// DTD File name

    49 	private String iFileName;

    50 

    51 	/**

    52 	 * Constructor.

    53 	 * 

    54 	 * @param aFileName

    55 	 *            DTD file name

    56 	 * @throws FileNotFoundException

    57 	 *             if the file can not be found

    58 	 */

    59 	public DTDInputSource(String aFileName) throws FileNotFoundException {

    60 		super( new FileReader( aFileName ) );

    61 		try {

    62 			preprocess(aFileName);

    63 		} catch (IOException e) {			

    64 			e.printStackTrace();

    65 		}

    66 		iFileName = aFileName;

    67 	}

    68 

    69 	/**

    70 	 * XML-DTD files should not contain invalid entity references. For example,

    71 	 * %N; is valid while %N is not. This method will validate and correct such

    72 	 * instances. Note: This was introduced because of a defect found in loc to

    73 	 * dtd converter tool. Once loc-dtd tool works fine, this step will not be

    74 	 * required.

    75 	 * 

    76 	 * @param fileName

    77 	 *            the dtd file that needs correction.

    78 	 * @throws IOException

    79 	 */

    80 	private void preprocess(String fileName) throws IOException {

    81 

    82 		

    83 		/**

    84 		 * We won't use this parameter as of now. If required, use

    85 		 * boolean fixDTD = InstallationManager.isFixDTD();

    86 		 * We may remove this if we find no use in future.

    87 		 */

    88 		boolean fixDTD = true;

    89 		if (!fixDTD) {

    90 			this.setCharacterStream(new FileReader(fileName));

    91 			return;

    92 		}

    93 		long fileLen = (new File(fileName)).length();

    94 		byte[] fileContents = new byte[(int) fileLen];

    95 		FileInputStream fis = new FileInputStream(fileName);

    96 		fis.read(fileContents);

    97 		fis.close();

    98 

    99 		String fileContentsString = new String(fileContents);

   100 		fileContentsString = fileContentsString.replace("(%N)", "(%N;)");

   101 		fileContentsString = fileContentsString.replace("(%U)", " (%U;)");

   102 		fileContentsString = fileContentsString.replace("%0U;", "%U;");

   103 		fileContentsString = fileContentsString.replace("%U(", "%U;(");

   104 		fileContentsString = fileContentsString.replace("%0U(", "%U;(");

   105 		fileContentsString = fileContentsString.replace("%U%N;", "%U;%N;");

   106 		fileContentsString = fileContentsString.replace("%U%N", "%U;%N;");

   107 

   108 		setByteStream(new ByteArrayInputStream(fileContentsString.getBytes()));

   109 	}

   110 

   111 	/*

   112 	 * (non-Javadoc)

   113 	 * 

   114 	 * @see org.xml.sax.InputSource#getCharacterStream()

   115 	 */

   116 	public Reader getCharacterStream() {

   117 		// Get the reader from the base class

   118 		Reader reader = super.getCharacterStream();

   119 

   120 		// Read the beginning of the file to get the BOM

   121 		byte[] buffer = new byte[BUFFER_LENGTH];

   122 		try {

   123 			// Read 3 bytes

   124 			for (int i = 0; i < buffer.length; i++) {

   125 				buffer[i] = (byte) reader.read();

   126 			}

   127 

   128 			int skip = 0;

   129 

   130 			// UTF-8 byte order mark (length 3 bytes)

   131 			if (Arrays.equals(BOM_UTF8, buffer)) {

   132 				skip = BOM_UTF8.length;

   133 			}

   134 			// UTF-16 byte order mark (length 2 bytes)

   135 			else {

   136 				byte[] compareBuffer = new byte[BOM_UTF16_BIG.length];

   137 				System.arraycopy(buffer, 0, compareBuffer, 0,

   138 						compareBuffer.length);

   139 

   140 				// Big and little endian

   141 				if (Arrays.equals(BOM_UTF16_BIG, compareBuffer)

   142 						|| Arrays.equals(BOM_UTF16_LIT, compareBuffer)) {

   143 					skip = BOM_UTF16_BIG.length;

   144 				}

   145 			}

   146 

   147 			// Reset not supported, a new reader must be created

   148 			FileReader fr = new FileReader(iFileName);

   149 			fr.skip(skip);

   150 

   151 			// Close the old reader

   152 			reader.close();

   153 

   154 			// Set the new reader back to the super class

   155 			super.setCharacterStream(fr);

   156 		} catch (Exception e) {

   157 			// Ignore errors, original (unfiltered) stream will be returned

   158 		}

   159 

   160 		return super.getCharacterStream();

   161 	}

   162 

   163 }