Java tutorial
/* * Copyright (c) 2007 Henri Sivonen * Copyright (c) 2007-2008 Mozilla Foundation * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the "Software"), * to deal in the Software without restriction, including without limitation * the rights to use, copy, modify, merge, publish, distribute, sublicense, * and/or sell copies of the Software, and to permit persons to whom the * Software is furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER * DEALINGS IN THE SOFTWARE. */ package nu.validator.htmlparser.gwt; import java.util.LinkedList; import nu.validator.htmlparser.common.XmlViolationPolicy; import nu.validator.htmlparser.impl.ErrorReportingTokenizer; import nu.validator.htmlparser.impl.Tokenizer; import nu.validator.htmlparser.impl.UTF16Buffer; import org.xml.sax.ErrorHandler; import org.xml.sax.SAXException; import org.xml.sax.SAXParseException; import com.google.gwt.core.client.JavaScriptObject; import com.google.gwt.user.client.Timer; /** * This class implements an HTML5 parser that exposes data through the DOM * interface. * * <p>By default, when using the constructor without arguments, the * this parser treats XML 1.0-incompatible infosets as fatal errors. * This corresponds to * <code>FATAL</code> as the general XML violation policy. To make the parser * support non-conforming HTML fully per the HTML 5 spec while on the other * hand potentially violating the DOM API contract, set the general XML * violation policy to <code>ALLOW</code>. This does not work with a standard * DOM implementation. Handling all input without fatal errors and without * violating the DOM API contract is possible by setting * the general XML violation policy to <code>ALTER_INFOSET</code>. <em>This * makes the parser non-conforming</em> but is probably the most useful * setting for most applications. * * <p>The doctype is not represented in the tree. * * <p>The document mode is represented as user data <code>DocumentMode</code> * object with the key <code>nu.validator.document-mode</code> on the document * node. * * <p>The form pointer is also stored as user data with the key * <code>nu.validator.form-pointer</code>. * * @version $Id: HtmlDocumentBuilder.java 255 2008-05-29 08:57:38Z hsivonen $ * @author hsivonen */ public class HtmlParser { private static final int CHUNK_SIZE = 512; private final Tokenizer tokenizer; private final BrowserTreeBuilder domTreeBuilder; private final StringBuilder documentWriteBuffer = new StringBuilder(); private ErrorHandler errorHandler; private UTF16Buffer stream; private int streamLength; private boolean lastWasCR; private boolean ending; private ParseEndListener parseEndListener; private final LinkedList<UTF16Buffer> bufferStack = new LinkedList<UTF16Buffer>(); /** * Instantiates the parser * * @param implementation * the DOM implementation * @param xmlPolicy the policy */ public HtmlParser(JavaScriptObject document) { this.domTreeBuilder = new BrowserTreeBuilder(document); this.tokenizer = new ErrorReportingTokenizer(domTreeBuilder); this.domTreeBuilder.setNamePolicy(XmlViolationPolicy.ALTER_INFOSET); this.tokenizer.setCommentPolicy(XmlViolationPolicy.ALTER_INFOSET); this.tokenizer.setContentNonXmlCharPolicy(XmlViolationPolicy.ALTER_INFOSET); this.tokenizer.setContentSpacePolicy(XmlViolationPolicy.ALTER_INFOSET); this.tokenizer.setNamePolicy(XmlViolationPolicy.ALTER_INFOSET); this.tokenizer.setXmlnsPolicy(XmlViolationPolicy.ALTER_INFOSET); } /** * Parses a document from a SAX <code>InputSource</code>. * @param is the source * @return the doc * @see javax.xml.parsers.DocumentBuilder#parse(org.xml.sax.InputSource) */ public void parse(String source, boolean useSetTimeouts, ParseEndListener callback) throws SAXException { parseEndListener = callback; domTreeBuilder.setFragmentContext(null); tokenize(source, useSetTimeouts, null); } /** * @param is * @throws SAXException * @throws IOException * @throws MalformedURLException */ private void tokenize(String source, final boolean useSetTimeouts, String context) throws SAXException { lastWasCR = false; ending = false; documentWriteBuffer.setLength(0); streamLength = source.length(); stream = new UTF16Buffer(source.toCharArray(), 0, (streamLength < CHUNK_SIZE ? streamLength : CHUNK_SIZE)); bufferStack.clear(); push(stream); domTreeBuilder.setFragmentContext(context == null ? null : context.intern()); tokenizer.start(); pump(useSetTimeouts); } private void pump(boolean useSetTimeouts) throws SAXException { if (ending) { tokenizer.end(); domTreeBuilder.getDocument(); // drops the internal reference parseEndListener.parseComplete(); // Don't schedule timeout return; } int docWriteLen = documentWriteBuffer.length(); if (docWriteLen > 0) { char[] newBuf = new char[docWriteLen]; documentWriteBuffer.getChars(0, docWriteLen, newBuf, 0); push(new UTF16Buffer(newBuf, 0, docWriteLen)); documentWriteBuffer.setLength(0); } for (;;) { UTF16Buffer buffer = peek(); if (!buffer.hasMore()) { if (buffer == stream) { if (buffer.getEnd() == streamLength) { // Stop parsing tokenizer.eof(); ending = true; break; } else { int newEnd = buffer.getStart() + CHUNK_SIZE; buffer.setEnd(newEnd < streamLength ? newEnd : streamLength); continue; } } else { pop(); continue; } } // now we have a non-empty buffer buffer.adjust(lastWasCR); lastWasCR = false; if (buffer.hasMore()) { lastWasCR = tokenizer.tokenizeBuffer(buffer); domTreeBuilder.maybeRunScript(); break; } else { continue; } } if (useSetTimeouts) { // schedule Timer timer = new Timer() { @Override public void run() { try { pump(true); } catch (SAXException e) { ending = true; if (errorHandler != null) { try { errorHandler .fatalError(new SAXParseException(e.getMessage(), null, null, -1, -1, e)); } catch (SAXException e1) { } } } } }; timer.schedule(1); } else { try { pump(false); } catch (SAXException e) { ending = true; if (errorHandler != null) { try { errorHandler.fatalError(new SAXParseException(e.getMessage(), null, null, -1, -1, e)); } catch (SAXException e1) { } } } } } private void push(UTF16Buffer buffer) { bufferStack.addLast(buffer); } private UTF16Buffer peek() { return bufferStack.getLast(); } private void pop() { bufferStack.removeLast(); } public void documentWrite(final String text) throws SAXException { UTF16Buffer buffer = new UTF16Buffer(text.toCharArray(), 0, text.length()); while (buffer.hasMore()) { buffer.adjust(lastWasCR); lastWasCR = false; if (buffer.hasMore()) { lastWasCR = tokenizer.tokenizeBuffer(buffer); domTreeBuilder.maybeRunScript(); } } } /** * @see javax.xml.parsers.DocumentBuilder#setErrorHandler(org.xml.sax.ErrorHandler) */ public void setErrorHandler(ErrorHandler errorHandler) { this.errorHandler = errorHandler; domTreeBuilder.setErrorHandler(errorHandler); tokenizer.setErrorHandler(errorHandler); } /** * Sets whether comment nodes appear in the tree. * @param ignoreComments <code>true</code> to ignore comments * @see nu.validator.htmlparser.impl.TreeBuilder#setIgnoringComments(boolean) */ public void setIgnoringComments(boolean ignoreComments) { domTreeBuilder.setIgnoringComments(ignoreComments); } /** * Sets whether the parser considers scripting to be enabled for noscript treatment. * @param scriptingEnabled <code>true</code> to enable * @see nu.validator.htmlparser.impl.TreeBuilder#setScriptingEnabled(boolean) */ public void setScriptingEnabled(boolean scriptingEnabled) { domTreeBuilder.setScriptingEnabled(scriptingEnabled); } }