/*

 * reserved comment block

 * DO NOT REMOVE OR ALTER!

 */

/*

 * Copyright 2003-2005 The Apache Software Foundation.

 *

 * 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 com.sun.org.apache.xerces.internal.xinclude;

import java.io.BufferedInputStream;

import java.io.IOException;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.io.Reader;

import java.net.HttpURLConnection;

import java.net.URL;

import java.net.URLConnection;

import java.util.Iterator;

import java.util.Locale;

import java.util.Map;

import com.sun.org.apache.xerces.internal.impl.XMLEntityManager;

import com.sun.org.apache.xerces.internal.impl.XMLErrorReporter;

import com.sun.org.apache.xerces.internal.impl.io.ASCIIReader;

import com.sun.org.apache.xerces.internal.impl.io.UTF8Reader;

import com.sun.org.apache.xerces.internal.impl.msg.XMLMessageFormatter;

import com.sun.org.apache.xerces.internal.util.EncodingMap;

import com.sun.org.apache.xerces.internal.util.HTTPInputSource;

import com.sun.org.apache.xerces.internal.util.MessageFormatter;

import com.sun.org.apache.xerces.internal.util.XMLChar;

import com.sun.org.apache.xerces.internal.xni.XMLString;

import com.sun.org.apache.xerces.internal.xni.parser.XMLInputSource;

/**

 * This class is used for reading resources requested in <include> elements,

 * when the parse attribute of the <include> element is "text".  Using this

 * class will open the location, detect the encoding, and discard the byte order

 * mark, if applicable.

 *

 * REVISIT:

 * Much of the code in this class is taken from XMLEntityManager.  It would be nice

 * if this code could be shared in some way.  However, since XMLEntityManager is used

 * for reading files as XML, and this needs to read files as text, there would need

 * to be some refactoring done.

 *

 * @author Michael Glavassevich, IBM

 * @author Peter McCracken, IBM

 * @author Ankit Pasricha, IBM

 * @author Arun Yadav, Sun Microsystems Inc.

 *

 *

 * @see XIncludeHandler

 */

public class XIncludeTextReader {

    private Reader fReader;

    private XIncludeHandler fHandler;

    private XMLInputSource fSource;

    private XMLErrorReporter fErrorReporter;

    private XMLString fTempString = new XMLString();

    /**

     * Construct the XIncludeReader using the XMLInputSource and XIncludeHandler.

     *

     * @param source The XMLInputSource to use.

     * @param handler The XIncludeHandler to use.

     * @param bufferSize The size of this text reader's buffer.

     */

    public XIncludeTextReader(XMLInputSource source, XIncludeHandler handler, int bufferSize)

        throws IOException {

        fHandler = handler;

        fSource = source;

        fTempString = new XMLString(new char[bufferSize + 1], 0, 0);

    }

    /**

     * Sets the XMLErrorReporter used for reporting errors while

     * reading the text include.

     *

     * @param errorReporter the XMLErrorReporter to be used for

     * reporting errors.

     */

    public void setErrorReporter(XMLErrorReporter errorReporter) {

        fErrorReporter = errorReporter;

    }

    /**

     * Return the Reader for given XMLInputSource.

     *

     * @param source The XMLInputSource to use.

     */

    protected Reader getReader(XMLInputSource source) throws IOException {

        if (source.getCharacterStream() != null) {

            return source.getCharacterStream();

        }

        else {

            InputStream stream = null;

            String encoding = source.getEncoding();

            if (encoding == null) {

                encoding = "UTF-8";

            }

            if (source.getByteStream() != null) {

                stream = source.getByteStream();

                // Wrap the InputStream so that it is possible to rewind it.

                if (!(stream instanceof BufferedInputStream)) {

                    stream = new BufferedInputStream(stream, fTempString.ch.length);

                }

            }

            else {

                String expandedSystemId = XMLEntityManager.expandSystemId(source.getSystemId(), source.getBaseSystemId(), false);

                URL url = new URL(expandedSystemId);

                URLConnection urlCon = url.openConnection();

                // If this is an HTTP connection attach any request properties to the request.

                if (urlCon instanceof HttpURLConnection && source instanceof HTTPInputSource) {

                    final HttpURLConnection urlConnection = (HttpURLConnection) urlCon;

                    final HTTPInputSource httpInputSource = (HTTPInputSource) source;

                    // set request properties

                    Iterator propIter = httpInputSource.getHTTPRequestProperties();

                    while (propIter.hasNext()) {

                        Map.Entry entry = (Map.Entry) propIter.next();

                        urlConnection.setRequestProperty((String) entry.getKey(), (String) entry.getValue());

                    }

                    // set preference for redirection

                    boolean followRedirects = httpInputSource.getFollowHTTPRedirects();

                    if (!followRedirects) {

                    }

                }

                // Wrap the InputStream so that it is possible to rewind it.

                stream = new BufferedInputStream(urlCon.getInputStream());

                // content type will be string like "text/xml; charset=UTF-8" or "text/xml"

                String rawContentType = urlCon.getContentType();

                // text/xml and application/xml offer only one optional parameter

                int index = (rawContentType != null) ? rawContentType.indexOf(';') : -1;

                String contentType = null;

                String charset = null;

                if (index != -1) {

                    // this should be something like "text/xml"

                    contentType = rawContentType.substring(0, index).trim();

                    // this should be something like "charset=UTF-8", but we want to

                    // strip it down to just "UTF-8"

                    charset = rawContentType.substring(index + 1).trim();

                    if (charset.startsWith("charset=")) {

                        // 8 is the length of "charset="

                        charset = charset.substring(8).trim();

                        // strip quotes, if present

                        if ((charset.charAt(0) == '"'

                            && charset.charAt(charset.length() - 1) == '"')

                            || (charset.charAt(0) == '\''

                                && charset.charAt(charset.length() - 1)

                                    == '\'')) {

                            charset =

                                charset.substring(1, charset.length() - 1);

                        }

                    }

                    else {

                        charset = null;

                    }

                }

                else {

                    contentType = rawContentType.trim();

                }

                String detectedEncoding = null;

                /**  The encoding of such a resource is determined by:

                    1 external encoding information, if available, otherwise

                         -- the most common type of external information is the "charset" parameter of a MIME package

                    2 if the media type of the resource is text/xml, application/xml, or matches the conventions text/*+xml or application/*+xml as described in XML Media Types [IETF RFC 3023], the encoding is recognized as specified in XML 1.0, otherwise

                    3 the value of the encoding attribute if one exists, otherwise

                    4 UTF-8.

                 **/

                if (contentType.equals("text/xml")) {

                    if (charset != null) {

                        detectedEncoding = charset;

                    }

                    else {

                        // see RFC2376 or 3023, section 3.1

                        detectedEncoding = "US-ASCII";

                    }

                }

                else if (contentType.equals("application/xml")) {

                    if (charset != null) {

                        detectedEncoding = charset;

                    }

                    else {

                        // see RFC2376 or 3023, section 3.2

                        detectedEncoding = getEncodingName(stream);

                    }

                }

                else if (contentType.endsWith("+xml")) {

                    detectedEncoding = getEncodingName(stream);

                }

                if (detectedEncoding != null) {

                    encoding = detectedEncoding;

                }

                // else 3 or 4.

            }

            encoding = encoding.toUpperCase(Locale.ENGLISH);

            // eat the Byte Order Mark

            encoding = consumeBOM(stream, encoding);

            // If the document is UTF-8 or US-ASCII use

            // the Xerces readers for these encodings. For

            // US-ASCII consult the encoding map since

            // this encoding has many aliases.

            if (encoding.equals("UTF-8")) {

                return new UTF8Reader(stream,

                    fTempString.ch.length,

                    fErrorReporter.getMessageFormatter(XMLMessageFormatter.XML_DOMAIN),

                    fErrorReporter.getLocale() );

            }

            // Try to use a Java reader.

            String javaEncoding = EncodingMap.getIANA2JavaMapping(encoding);

            // If the specified encoding wasn't a recognized IANA encoding throw an IOException.

            // The XIncludeHandler will report this as a ResourceError and then will

            // attempt to include a fallback if there is one.

            if (javaEncoding == null) {

                MessageFormatter aFormatter =

                    fErrorReporter.getMessageFormatter(XMLMessageFormatter.XML_DOMAIN);

                Locale aLocale = fErrorReporter.getLocale();

                throw new IOException( aFormatter.formatMessage( aLocale,

                    "EncodingDeclInvalid",

                    new Object[] {encoding} ) );

            }

            else if (javaEncoding.equals("ASCII")) {

                return new ASCIIReader(stream,

                    fTempString.ch.length,

                    fErrorReporter.getMessageFormatter(XMLMessageFormatter.XML_DOMAIN),

                    fErrorReporter.getLocale() );

            }

            return new InputStreamReader(stream, javaEncoding);

        }

    }

    /**

     * XMLEntityManager cares about endian-ness, since it creates its own optimized

     * readers. Since we're just using generic Java readers for now, we're not caring

     * about endian-ness.  If this changes, even more code needs to be copied from

     * XMLEntity manager. -- PJM

     */

    protected String getEncodingName(InputStream stream) throws IOException {

        final byte[] b4 = new byte[4];

        String encoding = null;

        // this has the potential to throw an exception

        // it will be fixed when we ensure the stream is rewindable (see note above)

        stream.mark(4);

        int count = stream.read(b4, 0, 4);

        stream.reset();

        if (count == 4) {

            encoding = getEncodingName(b4);

        }

        return encoding;

    }

    /**

     * Removes the byte order mark from the stream, if

     * it exists and returns the encoding name.

     *

     * @param stream

     * @param encoding

     * @throws IOException

     */

    protected String consumeBOM(InputStream stream, String encoding)

        throws IOException {

        byte[] b = new byte[3];

        int count = 0;

        stream.mark(3);

        if (encoding.equals("UTF-8")) {

            count = stream.read(b, 0, 3);

            if (count == 3) {

                final int b0 = b[0] & 0xFF;

                final int b1 = b[1] & 0xFF;

                final int b2 = b[2] & 0xFF;

                if (b0 != 0xEF || b1 != 0xBB || b2 != 0xBF) {

                    // First three bytes are not BOM, so reset.

                    stream.reset();

                }

            }

            else {

                stream.reset();

            }

        }

        else if (encoding.startsWith("UTF-16")) {

            count = stream.read(b, 0, 2);

            if (count == 2) {

                final int b0 = b[0] & 0xFF;

                final int b1 = b[1] & 0xFF;

                if (b0 == 0xFE && b1 == 0xFF) {

                    return "UTF-16BE";

                }

                else if (b0 == 0xFF && b1 == 0xFE) {

                    return "UTF-16LE";

                }

            }

            // First two bytes are not BOM, so reset.

            stream.reset();

        }

        // We could do UTF-32, but since the getEncodingName() doesn't support that

        // we won't support it here.

        // To implement UTF-32, look for:  00 00 FE FF for big-endian

        //                             or  FF FE 00 00 for little-endian

        return encoding;

    }

    /**

     * REVISIT: This code is taken from com.sun.org.apache.xerces.internal.impl.XMLEntityManager.

     *          Is there any way we can share the code, without having it implemented twice?

     *          I think we should make it public and static in XMLEntityManager. --PJM

     *

     * Returns the IANA encoding name that is auto-detected from

     * the bytes specified, with the endian-ness of that encoding where appropriate.

     *

     * @param b4    The first four bytes of the input.

     * @return the encoding name, or null if no encoding could be detected

     */

    protected String getEncodingName(byte[] b4) {

        // UTF-16, with BOM

        int b0 = b4[0] & 0xFF;

        int b1 = b4[1] & 0xFF;

        if (b0 == 0xFE && b1 == 0xFF) {

            // UTF-16, big-endian

            return "UTF-16BE";

        }

        if (b0 == 0xFF && b1 == 0xFE) {

            // UTF-16, little-endian

            return "UTF-16LE";

        }

        // UTF-8 with a BOM

        int b2 = b4[2] & 0xFF;

        if (b0 == 0xEF && b1 == 0xBB && b2 == 0xBF) {

            return "UTF-8";

        }

        // other encodings

        int b3 = b4[3] & 0xFF;

        if (b0 == 0x00 && b1 == 0x00 && b2 == 0x00 && b3 == 0x3C) {

            // UCS-4, big endian (1234)

            return "ISO-10646-UCS-4";

        }

        if (b0 == 0x3C && b1 == 0x00 && b2 == 0x00 && b3 == 0x00) {

            // UCS-4, little endian (4321)

            return "ISO-10646-UCS-4";

        }

        if (b0 == 0x00 && b1 == 0x00 && b2 == 0x3C && b3 == 0x00) {

            // UCS-4, unusual octet order (2143)

            return "ISO-10646-UCS-4";

        }

        if (b0 == 0x00 && b1 == 0x3C && b2 == 0x00 && b3 == 0x00) {

            // UCS-4, unusual octect order (3412)

            return "ISO-10646-UCS-4";

        }

        if (b0 == 0x00 && b1 == 0x3C && b2 == 0x00 && b3 == 0x3F) {

            // UTF-16, big-endian, no BOM

            // (or could turn out to be UCS-2...

            return "UTF-16BE";

        }

        if (b0 == 0x3C && b1 == 0x00 && b2 == 0x3F && b3 == 0x00) {

            // UTF-16, little-endian, no BOM

            // (or could turn out to be UCS-2...

            return "UTF-16LE";

        }

        if (b0 == 0x4C && b1 == 0x6F && b2 == 0xA7 && b3 == 0x94) {

            // EBCDIC

            // a la xerces1, return CP037 instead of EBCDIC here

            return "CP037";

        }

        // this signals us to use the value from the encoding attribute

        return null;

    } // getEncodingName(byte[]):Object[]

    /**

     * Read the input stream as text, and pass the text on to the XIncludeHandler

     * using calls to characters().  This will read all of the text it can from the

     * resource.

     *

     * @throws IOException

     */

    public void parse() throws IOException {

        fReader = getReader(fSource);

        fSource = null;

        int readSize = fReader.read(fTempString.ch, 0, fTempString.ch.length - 1);

        while (readSize != -1) {

            for (int i = 0; i < readSize; ++i) {

                char ch = fTempString.ch[i];

                if (!isValid(ch)) {

                    if (XMLChar.isHighSurrogate(ch)) {

                        int ch2;

                        // retrieve next character

                        if (++i < readSize) {

                            ch2 = fTempString.ch[i];

                        }

                        // handle rare boundary case

                        else {

                            ch2 = fReader.read();

                            if (ch2 != -1) {

                                fTempString.ch[readSize++] = (char) ch2;

                            }

                        }

                        if (XMLChar.isLowSurrogate(ch2)) {

                            // convert surrogates to a supplemental character

                            int sup = XMLChar.supplemental(ch, (char)ch2);

                            if (!isValid(sup)) {

                                fErrorReporter.reportError(XMLMessageFormatter.XML_DOMAIN,

                                                           "InvalidCharInContent",

                                                           new Object[] { Integer.toString(sup, 16) },

                                                           XMLErrorReporter.SEVERITY_FATAL_ERROR);

                            }

                        }

                        else {

                            fErrorReporter.reportError(XMLMessageFormatter.XML_DOMAIN,

                                                       "InvalidCharInContent",

                                                       new Object[] { Integer.toString(ch2, 16) },

                                                       XMLErrorReporter.SEVERITY_FATAL_ERROR);

                        }

                    }

                    else {

                        fErrorReporter.reportError(XMLMessageFormatter.XML_DOMAIN,

                                                   "InvalidCharInContent",

                                                   new Object[] { Integer.toString(ch, 16) },

                                                   XMLErrorReporter.SEVERITY_FATAL_ERROR);

                    }

                }

            }

            if (fHandler != null && readSize > 0) {

                fTempString.offset = 0;

                fTempString.length = readSize;

                fHandler.characters(

                    fTempString,

                    fHandler.modifyAugmentations(null, true));

            }

            readSize = fReader.read(fTempString.ch, 0, fTempString.ch.length - 1);

        }

    }

    /**

     * Sets the input source on this text reader.

     *

     * @param source The XMLInputSource to use.

     */

    public void setInputSource(XMLInputSource source) {

        fSource = source;

    }

    /**

     * Closes the stream.  Call this after parse(), or when there is no longer any need

     * for this object.

     *

     * @throws IOException

     */

    public void close() throws IOException {

        if (fReader != null) {

            fReader.close();

            fReader = null;

        }

    }

    /**

     * Returns true if the specified character is a valid XML character

     * as per the rules of XML 1.0.

     *

     * @param ch The character to check.

     */

    protected boolean isValid(int ch) {

        return XMLChar.isValid(ch);

    }

    /**

     * Sets the buffer size property for the reader which decides the chunk sizes that are parsed

     * by the reader at a time and passed to the handler

     *

     * @param bufferSize The size of the buffer desired

     */

    protected void setBufferSize(int bufferSize) {

        if (fTempString.ch.length != ++bufferSize) {

            fTempString.ch = new char[bufferSize];

        }

    }

}