| /* Parser.java -- HTML parser. |
| Copyright (C) 2005 Free Software Foundation, Inc. |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| GNU Classpath is distributed in the hope that it will be useful, but |
| WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
| 02110-1301 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| |
| package gnu.javax.swing.text.html.parser.support; |
| |
| import gnu.javax.swing.text.html.parser.htmlAttributeSet; |
| import gnu.javax.swing.text.html.parser.htmlValidator; |
| import gnu.javax.swing.text.html.parser.support.low.Constants; |
| import gnu.javax.swing.text.html.parser.support.low.ParseException; |
| import gnu.javax.swing.text.html.parser.support.low.ReaderTokenizer; |
| import gnu.javax.swing.text.html.parser.support.low.Token; |
| import gnu.javax.swing.text.html.parser.support.low.node; |
| import gnu.javax.swing.text.html.parser.support.low.pattern; |
| |
| import java.io.IOException; |
| import java.io.Reader; |
| |
| import java.util.Comparator; |
| import java.util.Set; |
| import java.util.TreeSet; |
| import java.util.Vector; |
| |
| import javax.swing.text.ChangedCharSetException; |
| import javax.swing.text.html.HTML; |
| import javax.swing.text.html.parser.AttributeList; |
| import javax.swing.text.html.parser.DTD; |
| import javax.swing.text.html.parser.DTDConstants; |
| import javax.swing.text.html.parser.Element; |
| import javax.swing.text.html.parser.Entity; |
| import javax.swing.text.html.parser.TagElement; |
| |
| /** |
| * <p>A simple error-tolerant HTML parser that uses a DTD document |
| * to access data on the possible tokens, arguments and syntax.</p> |
| * <p> The parser reads an HTML content from a Reader and calls various |
| * notifying methods (which should be overridden in a subclass) |
| * when tags or data are encountered.</p> |
| * <p>Some HTML elements need no opening or closing tags. The |
| * task of this parser is to invoke the tag handling methods also when |
| * the tags are not explicitly specified and must be supposed using |
| * information, stored in the DTD. |
| * For example, parsing the document |
| * <p><table><tr><td>a<td>b<td>c</tr> <br> |
| * will invoke exactly the handling methods exactly in the same order |
| * (and with the same parameters) as if parsing the document: <br> |
| * <em><html><head></head><body><table>< |
| * tbody></em><tr><td>a<em></td></em><td>b<em> |
| * </td></em><td>c<em></td></tr></em>< |
| * <em>/tbody></table></body></html></em></p> |
| * (supposed tags are given in italics). The parser also supports |
| * obsolete elements of HTML syntax.<p> |
| * </p> |
| * @author Audrius Meskauskas, Lithuania (AudriusA@Bioinformatics.org) |
| */ |
| public class Parser |
| extends ReaderTokenizer |
| implements DTDConstants |
| { |
| /** |
| * The current html tag. |
| */ |
| public Token hTag = new Token(); |
| |
| /** |
| * The document template description that will be used to parse the documents. |
| */ |
| protected DTD dtd; |
| |
| /** |
| * The value of this field determines whether or not the Parser will be |
| * strict in enforcing SGML compatibility. The default value is false, |
| * stating that the parser should do everything to parse and get at least |
| * some information even from the incorrectly written HTML input. |
| */ |
| protected boolean strict; |
| |
| /** |
| * This fields has positive values in preformatted tags. |
| */ |
| protected int preformatted = 0; |
| |
| /** |
| * The set of the document tags. This field is used for supporting |
| * markFirstTime(). |
| */ |
| private Set documentTags = |
| new TreeSet(new Comparator() |
| { |
| public int compare(Object a, Object b) |
| { |
| return ((String) a).compareToIgnoreCase((String) b); |
| } |
| } |
| ); |
| |
| /** |
| * The buffer to collect the incremental output like text or coment. |
| */ |
| private StringBuffer buffer = new StringBuffer(); |
| |
| /** |
| * The buffer to store the document title. |
| */ |
| private StringBuffer title = new StringBuffer(); |
| |
| /** |
| * The current token. |
| */ |
| private Token t; |
| |
| /** |
| * True means that the 'title' tag of this document has |
| * already been handled. |
| */ |
| private boolean titleHandled; |
| |
| /** |
| * True means that the 'title' tag is currently open and all |
| * text is also added to the title buffer. |
| */ |
| private boolean titleOpen; |
| |
| /** |
| * The attributes of the current HTML element. |
| * Package-private to avoid an accessor method. |
| */ |
| htmlAttributeSet attributes = |
| htmlAttributeSet.EMPTY_HTML_ATTRIBUTE_SET; |
| |
| /** |
| * The validator, controlling the forcible closing of the tags that |
| * (in accordance to dtd) are not allowed in the current context. |
| */ |
| private htmlValidator validator; |
| |
| /** |
| * Provides the default values for parameters in the case when these |
| * values are defined in the DTD. |
| */ |
| private parameterDefaulter defaulter; |
| |
| /** |
| * The text pre-processor for handling line ends and tabs. |
| */ |
| private textPreProcessor textProcessor = new textPreProcessor(); |
| |
| /** |
| * Creates a new Parser that uses the given |
| * {@link javax.swing.text.html.parser.DTD }. The only standard way |
| * to get an instance of DTD is to construct it manually, filling in |
| * all required fields. |
| * @param a_dtd The DTD to use. The parser behaviour after passing null |
| * as an argument is not documented and may vary between implementations. |
| */ |
| public Parser(DTD a_dtd) |
| { |
| if (a_dtd == null) |
| dtd = gnu.javax.swing.text.html.parser.HTML_401F.getInstance(); |
| else |
| dtd = a_dtd; |
| |
| defaulter = new parameterDefaulter(dtd); |
| |
| validator = |
| new htmlValidator(dtd) |
| { |
| /** |
| * Handles the error message. This method must be overridden to pass |
| * the message where required. |
| * @param msg The message text. |
| */ |
| protected void s_error(String msg) |
| { |
| error(msg); |
| } |
| |
| /** |
| * The method is called when the tag validator decides to close the |
| * tag on its own initiative. After reaching the end of stream, |
| * The tag validator closes all unclosed elements that are required |
| * to have the end (closing) tag. |
| * |
| * @param element The tag being fictionally (forcibly) closed. |
| */ |
| protected void handleSupposedEndTag(Element tElement) |
| { |
| // The tag is cloned as the original tElement is the |
| // element from the starting tag - may be accidently used |
| // somewhere else. |
| TagElement tag = makeTag(tElement, true); |
| _handleEndTag_remaining(tag); |
| } |
| |
| /** |
| * The method is called when the the tag validator decides to open |
| * the new tag on its own initiative. The tags, opened in this |
| * way, are HTML, HEAD and BODY. The attribute set is temporary |
| * assigned to the empty one, the previous value is |
| * restored before return. |
| * |
| * @param element The tag being fictionally (forcibly) closed. |
| */ |
| protected void handleSupposedStartTag(Element tElement) |
| { |
| TagElement tag = makeTag(tElement, true); |
| htmlAttributeSet were = attributes; |
| attributes = htmlAttributeSet.EMPTY_HTML_ATTRIBUTE_SET; |
| _handleStartTag(tag); |
| attributes = were; |
| } |
| }; |
| } |
| |
| /** |
| * Get the attributes of the current tag. |
| * @return The attribute set, representing the attributes of the current tag. |
| */ |
| public htmlAttributeSet getAttributes() |
| { |
| return attributes; |
| } |
| |
| /** |
| * Invokes the error handler. The default method in this implementation |
| * delegates the call to handleError, also providing the current line. |
| */ |
| public void error(String msg) |
| { |
| error(msg, getTokenAhead()); |
| } |
| |
| public void error(String msg, Token atToken) |
| { |
| if (atToken != null) |
| handleError(atToken.where.beginLine, |
| msg + ": line " + atToken.where.beginLine + |
| ", absolute pos " + atToken.where.startPosition |
| ); |
| else |
| handleError(0, msg); |
| } |
| |
| /** |
| * Invokes the error handler. The default method in this implementation |
| * delegates the call to error (parm1+": '"+parm2+"'"). |
| */ |
| public void error(String msg, String invalid) |
| { |
| error(msg + ": '" + invalid + "'"); |
| } |
| |
| /** |
| * Invokes the error handler. The default method in this implementation |
| * delegates the call to error (parm1+" "+ parm2+" "+ parm3). |
| */ |
| public void error(String parm1, String parm2, String parm3) |
| { |
| error(parm1 + " " + parm2 + " " + parm3); |
| } |
| |
| /** |
| * Invokes the error handler. The default method in this implementation |
| * delegates the call to error (parm1+" "+ parm2+" "+ parm3+" "+ parm4). |
| */ |
| public void error(String parm1, String parm2, String parm3, String parm4) |
| { |
| error(parm1 + " " + parm2 + " " + parm3 + " " + parm4); |
| } |
| |
| public void flushAttributes() |
| { |
| } |
| |
| /** |
| * Parse the HTML text, calling various methods in response to the |
| * occurence of the corresponding HTML constructions. |
| * @param reader The reader to read the source HTML from. |
| * @throws IOException If the reader throws one. |
| */ |
| public synchronized void parse(Reader reader) |
| throws IOException |
| { |
| reset(reader); |
| restart(); |
| try |
| { |
| parseDocument(); |
| validator.closeAll(); |
| } |
| catch (ParseException ex) |
| { |
| if (ex != null) |
| { |
| error("Unable to continue parsing the document", ex.getMessage()); |
| |
| Throwable cause = ex.getCause(); |
| if (cause instanceof IOException) |
| throw (IOException) cause; |
| } |
| } |
| } |
| |
| /** |
| * Parses DTD markup declaration. Currently returns null without action. |
| * @return null. |
| * @throws IOException |
| */ |
| public String parseDTDMarkup() |
| throws IOException |
| { |
| return null; |
| } |
| |
| /** |
| * Parse SGML insertion ( <! ... > ). When the |
| * the SGML insertion is found, this method is called, passing |
| * SGML in the string buffer as a parameter. The default method |
| * returns false without action and can be overridden to |
| * implement user - defined SGML support. |
| * <p> |
| * If you need more information about SGML insertions in HTML documents, |
| * the author suggests to read SGML tutorial on |
| * {@link http://www.w3.org/TR/WD-html40-970708/intro/sgmltut.html}. |
| * We also recommend Goldfarb C.F (1991) <i>The SGML Handbook</i>, |
| * Oxford University Press, 688 p, ISBN: 0198537379. |
| * </p> |
| * @param strBuff |
| * @return true if this is a valid DTD markup declaration. |
| * @throws IOException |
| */ |
| public boolean parseMarkupDeclarations(StringBuffer strBuff) |
| throws IOException |
| { |
| return false; |
| } |
| |
| /** |
| * Get the first line of the last parsed token. |
| */ |
| protected int getCurrentLine() |
| { |
| return hTag.where.beginLine; |
| } |
| |
| /** |
| * Read parseable character data, add to buffer. |
| * @param clearBuffer If true, buffer if filled by CDATA section, |
| * otherwise the section is appended to the existing content of the |
| * buffer. |
| * |
| * @throws ParseException |
| */ |
| protected void CDATA(boolean clearBuffer) |
| throws ParseException |
| { |
| Token start = hTag = getTokenAhead(); |
| |
| if (clearBuffer) |
| buffer.setLength(0); |
| |
| // Handle expected EOF. |
| if (start.kind == EOF) |
| return; |
| |
| read: |
| while (true) |
| { |
| t = getTokenAhead(); |
| if (t.kind == EOF) |
| { |
| error("unexpected eof", t); |
| break read; |
| } |
| else if (t.kind == BEGIN) |
| break read; |
| else if (t.kind == Constants.ENTITY) |
| { |
| resolveAndAppendEntity(t); |
| getNextToken(); |
| } |
| else |
| { |
| append(t); |
| getNextToken(); |
| } |
| } |
| hTag = new Token(start, getTokenAhead(0)); |
| if (buffer.length() != 0) |
| _handleText(); |
| } |
| |
| /** |
| * Process Comment. This method skips till --> without |
| * taking SGML constructs into consideration. The supported SGML |
| * constructs are handled separately. |
| */ |
| protected void Comment() |
| throws ParseException |
| { |
| buffer.setLength(0); |
| |
| Token start = hTag = mustBe(BEGIN); |
| optional(WS); |
| mustBe(EXCLAMATION); |
| optional(WS); |
| mustBe(DOUBLE_DASH); |
| |
| Token t; |
| Token last; |
| |
| comment: |
| while (true) |
| { |
| t = getTokenAhead(); |
| if (t.kind == EOF) |
| { |
| handleEOFInComment(); |
| last = t; |
| break comment; |
| } |
| else if (COMMENT_END.matches(this)) |
| { |
| mustBe(DOUBLE_DASH); |
| optional(WS); |
| last = mustBe(END); |
| break comment; |
| } |
| else if (COMMENT_TRIPLEDASH_END.matches(this)) |
| { |
| mustBe(DOUBLE_DASH); |
| t = mustBe(NUMTOKEN); |
| if (t.getImage().equals("-")) |
| { |
| append(t); |
| last = mustBe(END); |
| break comment; |
| } |
| else |
| { |
| buffer.append("--"); |
| append(t); |
| t = getTokenAhead(); |
| } |
| } |
| else |
| /* The lllll-- can match as NUMTOKEN */ |
| if ((t.getImage().endsWith("--")) && |
| ( |
| getTokenAhead(1).kind == END || |
| (getTokenAhead(1).kind == WS && getTokenAhead(2).kind == END) |
| ) |
| ) |
| { |
| buffer.append(t.getImage().substring(0, t.getImage().length() - 2)); |
| |
| /* Skip the closing > that we have already checked. */ |
| last = mustBe(t.kind); |
| break comment; |
| } |
| else |
| append(t); |
| mustBe(t.kind); |
| } |
| hTag = new Token(start, last); |
| handleComment(); |
| } |
| |
| /** |
| * Read a script. The text, returned without any changes, |
| * is terminated only by the closing tag SCRIPT. |
| */ |
| protected void Script() |
| throws ParseException |
| { |
| Token name; |
| |
| Token start = hTag = mustBe(BEGIN); |
| optional(WS); |
| |
| name = mustBe(SCRIPT); |
| |
| optional(WS); |
| |
| restOfTag(false, name, start); |
| |
| buffer.setLength(0); |
| |
| script: |
| while (!SCRIPT_CLOSE.matches(this)) |
| { |
| append(getNextToken()); |
| } |
| |
| consume(SCRIPT_CLOSE); |
| |
| _handleText(); |
| |
| endTag(false); |
| _handleEndTag(makeTagElement(name.getImage(), false)); |
| } |
| |
| /** |
| * Process SGML insertion that is not a comment. |
| */ |
| protected void Sgml() |
| throws ParseException |
| { |
| if (COMMENT_OPEN.matches(this)) |
| Comment(); |
| else // skip till ">" |
| { |
| Token start = hTag = mustBe(BEGIN); |
| optional(WS); |
| mustBe(EXCLAMATION); |
| |
| buffer.setLength(0); |
| read: |
| while (true) |
| { |
| t = getNextToken(); |
| if (t.kind == Constants.ENTITY) |
| { |
| resolveAndAppendEntity(t); |
| } |
| else if (t.kind == EOF) |
| { |
| error("unexpected eof", t); |
| break read; |
| } |
| else if (t.kind == END) |
| break read; |
| else |
| append(t); |
| } |
| |
| try |
| { |
| parseMarkupDeclarations(buffer); |
| } |
| catch (IOException ex) |
| { |
| error("Unable to parse SGML insertion: '" + buffer + "'", |
| new Token(start, t) |
| ); |
| } |
| } |
| } |
| |
| /** |
| * Read a style definition. The text, returned without any changes, |
| * is terminated only by the closing tag STYLE. |
| */ |
| protected void Style() |
| throws ParseException |
| { |
| Token name; |
| |
| Token start = hTag = mustBe(BEGIN); |
| optional(WS); |
| |
| name = mustBe(STYLE); |
| |
| optional(WS); |
| |
| restOfTag(false, name, start); |
| |
| buffer.setLength(0); |
| |
| style: |
| while (!STYLE_CLOSE.matches(this)) |
| { |
| append(getNextToken()); |
| } |
| |
| consume(STYLE_CLOSE); |
| |
| _handleText(); |
| |
| endTag(false); |
| _handleEndTag(makeTagElement(name.getImage(), false)); |
| } |
| |
| /** |
| * Read a html tag. |
| */ |
| protected void Tag() |
| throws ParseException |
| { |
| mark(true); |
| |
| boolean closing = false; |
| Token name; |
| Token start = hTag = mustBe(BEGIN); |
| |
| optional(WS); |
| name = getNextToken(); |
| optional(WS); |
| |
| if (name.kind == SLASH) |
| { |
| closing = true; |
| name = getNextToken(); |
| } |
| |
| restOfTag(closing, name, start); |
| } |
| |
| /** |
| * A hook, for operations, preceeding call to handleText. |
| * Handle text in a string buffer. |
| * In non - preformatted mode, all line breaks immediately following the |
| * start tag and immediately before an end tag is discarded, |
| * \r, \n and \t are replaced by spaces, multiple space are replaced |
| * by the single one and the result is moved into array, |
| * passing it to handleText(). |
| */ |
| protected void _handleText() |
| { |
| char[] text; |
| |
| if (preformatted > 0) |
| text = textProcessor.preprocessPreformatted(buffer); |
| else |
| text = textProcessor.preprocess(buffer); |
| |
| if (text != null && text.length > 0) |
| { |
| TagElement pcdata = new TagElement(dtd.getElement("#pcdata")); |
| attributes = htmlAttributeSet.EMPTY_HTML_ATTRIBUTE_SET; |
| _handleEmptyTag(pcdata); |
| |
| handleText(text); |
| if (titleOpen) |
| title.append(text); |
| } |
| } |
| |
| /** |
| * Add the image of this token to the buffer. |
| * @param t A token to append. |
| */ |
| protected final void append(Token t) |
| { |
| if (t.kind != EOF) |
| t.appendTo(buffer); |
| } |
| |
| /** |
| * Consume pattern that must match. |
| * @param p A pattern to consume. |
| */ |
| protected final void consume(pattern p) |
| { |
| node n; |
| for (int i = 0; i < p.nodes.length; i++) |
| { |
| n = p.nodes [ i ]; |
| if (n.optional) |
| optional(n.kind); |
| else |
| mustBe(n.kind); |
| } |
| } |
| |
| /** |
| * The method is called when the HTML end (closing) tag is found or if |
| * the parser concludes that the one should be present in the |
| * current position. The method is called immediatly |
| * before calling the handleEndTag(). |
| * @param omitted True if the tag is no actually present in the document, |
| * but is supposed by the parser (like </html> at the end of the |
| * document). |
| */ |
| protected void endTag(boolean omitted) |
| { |
| } |
| |
| /** |
| * Handle HTML comment. The default method returns without action. |
| * @param comment |
| */ |
| protected void handleComment(char[] comment) |
| { |
| } |
| |
| /** |
| * This is additionally called in when the HTML content terminates |
| * without closing the HTML comment. This can only happen if the |
| * HTML document contains errors (for example, the closing --;gt is |
| * missing. |
| */ |
| protected void handleEOFInComment() |
| { |
| error("Unclosed comment"); |
| } |
| |
| /** |
| * Handle the tag with no content, like <br>. The method is |
| * called for the elements that, in accordance with the current DTD, |
| * has an empty content. |
| * @param The tag being handled. |
| * @throws javax.swing.text.ChangedCharSetException |
| */ |
| protected void handleEmptyTag(TagElement tag) |
| throws javax.swing.text.ChangedCharSetException |
| { |
| } |
| |
| /** |
| * The method is called when the HTML closing tag ((like </table>) |
| * is found or if the parser concludes that the one should be present |
| * in the current position. |
| * @param The tag |
| */ |
| protected void handleEndTag(TagElement tag) |
| { |
| } |
| |
| /* Handle error that has occured in the given line. */ |
| protected void handleError(int line, String message) |
| { |
| } |
| |
| /** |
| * The method is called when the HTML opening tag ((like <table>) |
| * is found or if the parser concludes that the one should be present |
| * in the current position. |
| * @param The tag |
| */ |
| protected void handleStartTag(TagElement tag) |
| { |
| } |
| |
| /** |
| * Handle the text section. |
| * <p> For non-preformatted section, the parser replaces |
| * \t, \r and \n by spaces and then multiple spaces |
| * by a single space. Additionaly, all whitespace around |
| * tags is discarded. |
| * </p> |
| * <p> For pre-formatted text (inside TEXAREA and PRE), the parser preserves |
| * all tabs and spaces, but removes <b>one</b> bounding \r, \n or \r\n, |
| * if it is present. Additionally, it replaces each occurence of \r or \r\n |
| * by a single \n.</p> |
| * |
| * @param text A section text. |
| */ |
| protected void handleText(char[] text) |
| { |
| } |
| |
| /** |
| * Handle HTML <title> tag. This method is invoked when |
| * both title starting and closing tags are already behind. |
| * The passed argument contains the concatenation of all |
| * title text sections. |
| * @param The title text. |
| */ |
| protected void handleTitle(char[] title) |
| { |
| } |
| |
| /** |
| * Constructs the tag from the given element. In this implementation, |
| * this is defined, but never called. |
| * @return the tag |
| */ |
| protected TagElement makeTag(Element element) |
| { |
| return makeTag(element, false); |
| } |
| |
| /** |
| * Constructs the tag from the given element. |
| * @param the tag base {@link javax.swing.text.html.parser.Element} |
| * @param isSupposed true if the tag is not actually present in the |
| * html input, but the parser supposes that it should to occur in |
| * the current location. |
| * @return the tag |
| */ |
| protected TagElement makeTag(Element element, boolean isSupposed) |
| { |
| return new TagElement(element, isSupposed); |
| } |
| |
| /** |
| * This is called when the tag, representing the given element, |
| * occurs first time in the document. |
| * @param element |
| */ |
| protected void markFirstTime(Element element) |
| { |
| } |
| |
| /** |
| * Consume the token that was checked before and hence MUST be present. |
| * @param kind The kind of token to consume. |
| */ |
| protected Token mustBe(int kind) |
| { |
| if (getTokenAhead().kind == kind) |
| return getNextToken(); |
| else |
| { |
| String ei = ""; |
| if (kind < 1000) |
| ei = " ('" + (char) kind + "') "; |
| throw new AssertionError("The token of kind " + kind + ei + |
| " MUST be here," |
| ); |
| } |
| } |
| |
| /** |
| * Handle attribute without value. The default method uses |
| * the only allowed attribute value from DTD. |
| * If the attribute is unknown or allows several values, |
| * the HTML.NULL_ATTRIBUTE_VALUE is used. The attribute with |
| * this value is added to the attribute set. |
| * @param element The name of element. |
| * @param attribute The name of attribute without value. |
| */ |
| protected void noValueAttribute(String element, String attribute) |
| { |
| Object value = HTML.NULL_ATTRIBUTE_VALUE; |
| |
| Element e = (Element) dtd.elementHash.get(element.toLowerCase()); |
| if (e != null) |
| { |
| AttributeList attr = e.getAttribute(attribute); |
| if (attr != null) |
| { |
| Vector values = attr.values; |
| if (values != null && values.size() == 1) |
| value = values.get(0); |
| } |
| } |
| attributes.addAttribute(attribute, value); |
| } |
| |
| /** |
| * Consume the optional token, if present. |
| * @param kind The kind of token to consume. |
| */ |
| protected Token optional(int kind) |
| { |
| if (getTokenAhead().kind == kind) |
| return getNextToken(); |
| else |
| return null; |
| } |
| |
| /** Parse the html document. */ |
| protected void parseDocument() |
| throws ParseException |
| { |
| while (getTokenAhead().kind != EOF) |
| { |
| advanced = false; |
| if (TAG.matches(this)) |
| Tag(); |
| else if (COMMENT_OPEN.matches(this)) |
| Comment(); |
| else if (STYLE_OPEN.matches(this)) |
| Style(); |
| else if (SCRIPT_OPEN.matches(this)) |
| Script(); |
| else if (SGML.matches(this)) |
| Sgml(); |
| else |
| CDATA(true); |
| |
| // Surely HTML error, treat as a text. |
| if (!advanced) |
| { |
| Token wrong = getNextToken(); |
| error("unexpected '" + wrong.getImage() + "'", wrong); |
| buffer.setLength(0); |
| buffer.append(wrong.getImage()); |
| _handleText(); |
| } |
| } |
| } |
| |
| /** |
| * Read the element attributes, adding them into attribute set. |
| * @param element The element name (needed to access attribute |
| * information in dtd). |
| */ |
| protected void readAttributes(String element) |
| { |
| Token name; |
| Token value; |
| Token next; |
| String attrValue; |
| |
| attributes = new htmlAttributeSet(); |
| |
| optional(WS); |
| |
| attributeReading: |
| while (getTokenAhead().kind == NUMTOKEN) |
| { |
| name = getNextToken(); |
| optional(WS); |
| |
| next = getTokenAhead(); |
| if (next.kind == EQ) |
| { |
| mustBe(EQ); |
| optional(WS); |
| |
| next = getNextToken(); |
| |
| switch (next.kind) |
| { |
| case QUOT: |
| |
| // read "quoted" attribute. |
| buffer.setLength(0); |
| readTillTokenE(QUOT); |
| attrValue = buffer.toString(); |
| break; |
| |
| case AP: |
| |
| // read 'quoted' attribute. |
| buffer.setLength(0); |
| readTillTokenE(AP); |
| attrValue = buffer.toString(); |
| break; |
| |
| // read unquoted attribute. |
| case NUMTOKEN: |
| value = next; |
| optional(WS); |
| |
| // Check maybe the opening quote is missing. |
| next = getTokenAhead(); |
| if (bQUOTING.get(next.kind)) |
| { |
| hTag = next; |
| error("The value without opening quote is closed with '" |
| + next.getImage() + "'"); |
| attrValue = value.getImage(); |
| } |
| else if (next.kind == SLASH) |
| // The slash in this context is treated as the ordinary |
| // character, not as a token. The slash may be part of |
| // the unquoted URL. |
| { |
| StringBuffer image = new StringBuffer(value.getImage()); |
| while (next.kind == NUMTOKEN || next.kind == SLASH) |
| { |
| image.append(getNextToken().getImage()); |
| next = getTokenAhead(); |
| } |
| attrValue = image.toString(); |
| } |
| else |
| attrValue = value.getImage(); |
| break; |
| |
| case SLASH: |
| value = next; |
| optional(WS); |
| |
| // Check maybe the opening quote is missing. |
| next = getTokenAhead(); |
| if (bQUOTING.get(next.kind)) |
| { |
| hTag = next; |
| error("The value without opening quote is closed with '" |
| + next.getImage() + "'"); |
| attrValue = value.getImage(); |
| } |
| else if (next.kind == NUMTOKEN || next.kind == SLASH) |
| // The slash in this context is treated as the ordinary |
| // character, not as a token. The slash may be part of |
| // the unquoted URL. |
| { |
| StringBuffer image = new StringBuffer(value.getImage()); |
| while (next.kind == NUMTOKEN || next.kind == SLASH) |
| { |
| image.append(getNextToken().getImage()); |
| next = getTokenAhead(); |
| } |
| attrValue = image.toString(); |
| } |
| else |
| attrValue = value.getImage(); |
| break; |
| default: |
| break attributeReading; |
| } |
| attributes.addAttribute(name.getImage(), attrValue); |
| optional(WS); |
| } |
| else |
| // The '=' is missing: attribute without value. |
| { |
| noValueAttribute(element, name.getImage()); |
| } |
| } |
| } |
| |
| /** |
| * Return string, corresponding the given named entity. The name is passed |
| * with the preceeding &, but without the ending semicolon. |
| */ |
| protected String resolveNamedEntity(final String a_tag) |
| { |
| // Discard & |
| if (!a_tag.startsWith("&")) |
| throw new AssertionError("Named entity " + a_tag + |
| " must start witn '&'." |
| ); |
| |
| String tag = a_tag.substring(1); |
| |
| try |
| { |
| Entity entity = dtd.getEntity(tag); |
| if (entity != null) |
| return entity.getString(); |
| |
| entity = dtd.getEntity(tag.toLowerCase()); |
| |
| if (entity != null) |
| { |
| error("The name of this entity should be in lowercase", a_tag); |
| return entity.getString(); |
| } |
| } |
| catch (IndexOutOfBoundsException ibx) |
| { |
| /* The error will be reported. */ |
| } |
| |
| error("Unknown named entity", a_tag); |
| return a_tag; |
| } |
| |
| /** |
| * Return char, corresponding the given numeric entity. |
| * The name is passed with the preceeding &#, but without |
| * the ending semicolon. |
| */ |
| protected char resolveNumericEntity(final String a_tag) |
| { |
| // Discard &# |
| if (!a_tag.startsWith("&#")) |
| throw new AssertionError("Numeric entity " + a_tag + |
| " must start witn '&#'." |
| ); |
| |
| String tag = a_tag.substring(2); |
| |
| try |
| { |
| // Determine the encoding type: |
| char cx = tag.charAt(0); |
| if (cx == 'x' || cx == 'X') // Hexadecimal &#Xnnn; |
| |
| return (char) Integer.parseInt(tag.substring(1), 16); |
| |
| return (char) Integer.parseInt(tag); |
| } |
| |
| /* The error will be reported. */ |
| catch (NumberFormatException nex) |
| { |
| } |
| catch (IndexOutOfBoundsException ix) |
| { |
| } |
| |
| error("Invalid numeric entity", a_tag); |
| return '?'; |
| } |
| |
| /** |
| * Reset all fields into the intial default state, preparing the |
| * parset for parsing the next document. |
| */ |
| protected void restart() |
| { |
| documentTags.clear(); |
| titleHandled = false; |
| titleOpen = false; |
| buffer.setLength(0); |
| title.setLength(0); |
| validator.restart(); |
| } |
| |
| /** |
| * The method is called when the HTML opening tag ((like <table>) |
| * is found or if the parser concludes that the one should be present |
| * in the current position. The method is called immediately before |
| * calling the handleStartTag. |
| * @param The tag |
| */ |
| protected void startTag(TagElement tag) |
| throws ChangedCharSetException |
| { |
| } |
| |
| /** |
| * Handle a complete element, when the tag content is already present in the |
| * buffer and both starting and heading tags behind. This is called |
| * in the case when the tag text must not be parsed for the nested |
| * elements (elements STYLE and SCRIPT). |
| */ |
| private void _handleCompleteElement(TagElement tag) |
| { |
| _handleStartTag(tag); |
| |
| // Suppress inclusion of the SCRIPT ans STYLE texts into the title. |
| HTML.Tag h = tag.getHTMLTag(); |
| if (h == HTML.Tag.SCRIPT || h == HTML.Tag.STYLE) |
| { |
| boolean tmp = titleOpen; |
| titleOpen = false; |
| _handleText(); |
| titleOpen = tmp; |
| } |
| else |
| _handleText(); |
| |
| _handleEndTag(tag); |
| } |
| |
| /** |
| * A hooks for operations, preceeding call to handleEmptyTag(). |
| * Handle the tag with no content, like <br>. As no any |
| * nested tags are expected, the tag validator is not involved. |
| * @param The tag being handled. |
| */ |
| private void _handleEmptyTag(TagElement tag) |
| { |
| try |
| { |
| validator.validateTag(tag, attributes); |
| handleEmptyTag(tag); |
| } |
| catch (ChangedCharSetException ex) |
| { |
| error("Changed charset exception:", ex.getMessage()); |
| } |
| } |
| |
| /** |
| * A hooks for operations, preceeding call to handleEndTag(). |
| * The method is called when the HTML closing tag |
| * is found. Calls handleTitle after closing the 'title' tag. |
| * @param The tag |
| */ |
| private void _handleEndTag(TagElement tag) |
| { |
| validator.closeTag(tag); |
| _handleEndTag_remaining(tag); |
| } |
| |
| /** |
| * Actions that are also required if the closing action was |
| * initiated by the tag validator. |
| * Package-private to avoid an accessor method. |
| */ |
| void _handleEndTag_remaining(TagElement tag) |
| { |
| HTML.Tag h = tag.getHTMLTag(); |
| |
| handleEndTag(tag); |
| endTag(tag.fictional()); |
| |
| if (h.isPreformatted()) |
| preformatted--; |
| if (preformatted < 0) |
| preformatted = 0; |
| |
| if (h == HTML.Tag.TITLE) |
| { |
| titleOpen = false; |
| titleHandled = true; |
| |
| char[] a = new char[ title.length() ]; |
| title.getChars(0, a.length, a, 0); |
| handleTitle(a); |
| } |
| } |
| |
| /** |
| * A hooks for operations, preceeding call to handleStartTag(). |
| * The method is called when the HTML opening tag ((like <table>) |
| * is found. |
| * Package-private to avoid an accessor method. |
| * @param The tag |
| */ |
| void _handleStartTag(TagElement tag) |
| { |
| validator.openTag(tag, attributes); |
| startingTag(tag); |
| handleStartTag(tag); |
| |
| HTML.Tag h = tag.getHTMLTag(); |
| |
| if (h.isPreformatted()) |
| preformatted++; |
| |
| if (h == HTML.Tag.TITLE) |
| { |
| if (titleHandled) |
| error("Repetetive <TITLE> tag"); |
| titleOpen = true; |
| titleHandled = false; |
| } |
| } |
| |
| /** |
| * Resume parsing after heavy errors in HTML tag structure. |
| * @throws ParseException |
| */ |
| private void forciblyCloseTheTag() |
| throws ParseException |
| { |
| int closeAt = 0; |
| buffer.setLength(0); |
| |
| ahead: |
| for (int i = 1; i < 100; i++) |
| { |
| t = getTokenAhead(i - 1); |
| if (t.kind == EOF || t.kind == BEGIN) |
| break ahead; |
| if (t.kind == END) |
| { |
| /* Closing '>' found. */ |
| closeAt = i; |
| break ahead; |
| } |
| } |
| if (closeAt > 0) |
| { |
| buffer.append("Ignoring '"); |
| for (int i = 1; i <= closeAt; i++) |
| { |
| t = getNextToken(); |
| append(t); |
| } |
| buffer.append('\''); |
| error(buffer.toString()); |
| } |
| } |
| |
| /** |
| * Handle comment in string buffer. You can avoid allocating a char |
| * array each time by processing your comment directly here. |
| */ |
| private void handleComment() |
| { |
| char[] a = new char[ buffer.length() ]; |
| buffer.getChars(0, a.length, a, 0); |
| handleComment(a); |
| } |
| |
| private TagElement makeTagElement(String name, boolean isSupposed) |
| { |
| Element e = (Element) dtd.elementHash.get(name.toLowerCase()); |
| if (e == null) |
| { |
| error("Unknown tag <" + name + ">"); |
| e = dtd.getElement(name); |
| e.name = name.toUpperCase(); |
| e.index = -1; |
| } |
| |
| if (!documentTags.contains(e.name)) |
| { |
| markFirstTime(e); |
| documentTags.add(e.name); |
| } |
| |
| return makeTag(e, isSupposed); |
| } |
| |
| /** |
| * Read till the given token, resolving entities. Consume the given |
| * token without adding it to buffer. |
| * @param till The token to read till |
| * @throws ParseException |
| */ |
| private void readTillTokenE(int till) |
| throws ParseException |
| { |
| buffer.setLength(0); |
| read: |
| while (true) |
| { |
| t = getNextToken(); |
| if (t.kind == Constants.ENTITY) |
| { |
| resolveAndAppendEntity(t); |
| } |
| else if (t.kind == EOF) |
| { |
| error("unexpected eof", t); |
| break read; |
| } |
| else if (t.kind == till) |
| break read; |
| else if (t.kind == WS) |
| { |
| // Processing whitespace in accordance with CDATA rules: |
| String s = t.getImage(); |
| char c; |
| for (int i = 0; i < s.length(); i++) |
| { |
| c = s.charAt(i); |
| if (c == '\r') |
| buffer.append(' '); // CR replaced by space |
| else if (c == '\n') |
| ; // LF ignored |
| else if (c == '\t') |
| buffer.append(' '); // Tab replaced by space |
| else |
| buffer.append(c); |
| } |
| } |
| else |
| append(t); |
| } |
| } |
| |
| /** |
| * Resolve the entity and append it to the end of buffer. |
| * @param entity |
| */ |
| private void resolveAndAppendEntity(Token entity) |
| { |
| switch (entity.category) |
| { |
| case ENTITY_NAMED : |
| buffer.append(resolveNamedEntity(entity.getImage())); |
| break; |
| |
| case ENTITY_NUMERIC : |
| buffer.append(resolveNumericEntity(entity.getImage())); |
| break; |
| |
| default : |
| throw new AssertionError("Invalid entity category " + |
| entity.category |
| ); |
| } |
| } |
| |
| /** |
| * Handle the remaining of HTML tags. This is a common end for |
| * TAG, SCRIPT and STYLE. |
| * @param closing True for closing tags ( </TAG> ). |
| * @param name Name of element |
| * @param start Token where element has started |
| * @throws ParseException |
| */ |
| private void restOfTag(boolean closing, Token name, Token start) |
| throws ParseException |
| { |
| boolean end = false; |
| Token next; |
| |
| optional(WS); |
| |
| readAttributes(name.getImage()); |
| |
| optional(WS); |
| |
| next = getTokenAhead(); |
| if (next.kind == END) |
| { |
| mustBe(END); |
| end = true; |
| } |
| |
| hTag = new Token(start, next); |
| |
| attributes.setResolveParent(defaulter.getDefaultParameters(name.getImage())); |
| |
| if (!end) |
| { |
| // The tag body contains errors. If additionally the tag |
| // name is not valid, this construction is treated as text. |
| if (dtd.elementHash.get(name.getImage().toLowerCase()) == null && |
| backupMode |
| ) |
| { |
| error("Errors in tag body and unknown tag name. " + |
| "Treating the tag as a text." |
| ); |
| reset(); |
| |
| hTag = mustBe(BEGIN); |
| buffer.setLength(0); |
| buffer.append(hTag.getImage()); |
| CDATA(false); |
| return; |
| } |
| else |
| { |
| error("Forcibly closing invalid parameter list"); |
| forciblyCloseTheTag(); |
| } |
| } |
| |
| if (closing) |
| { |
| endTag(false); |
| _handleEndTag(makeTagElement(name.getImage(), false)); |
| } |
| else |
| { |
| TagElement te = makeTagElement(name.getImage(), false); |
| if (te.getElement().type == DTDConstants.EMPTY) |
| _handleEmptyTag(te); |
| else |
| _handleStartTag(te); |
| } |
| } |
| |
| /** |
| * This should fire additional actions in response to the |
| * ChangedCharSetException. The current implementation |
| * does nothing. |
| * @param tag |
| */ |
| private void startingTag(TagElement tag) |
| { |
| try |
| { |
| startTag(tag); |
| } |
| catch (ChangedCharSetException cax) |
| { |
| error("Invalid change of charset"); |
| } |
| } |
| |
| private void ws_error() |
| { |
| error("Whitespace here is not permitted"); |
| } |
| } |