parser.java

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/*
 * Copyright 1999,2004 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 org.apache.jasper.compiler;

import java.io.CharArrayWriter;
import java.io.FileNotFoundException;
import java.net.URL;
import java.util.Iterator;
import java.util.List;

import javax.servlet.jsp.tagext.TagAttributeInfo;
import javax.servlet.jsp.tagext.TagFileInfo;
import javax.servlet.jsp.tagext.TagInfo;
import javax.servlet.jsp.tagext.TagLibraryInfo;

import org.apache.jasper.Constants;
import org.apache.jasper.JasperException;
import org.apache.jasper.JspCompilationContext;
import org.xml.sax.Attributes;
import org.xml.sax.helpers.AttributesImpl;

/**
 * This class implements a parser for a JSP page (non-xml view).
 * JSP page grammar is included here for reference.  The token '#'
 * that appears in the production indicates the current input token
 * location in the production.
 * 
 * @author Kin-man Chung
 * @author Shawn Bayern
 * @author Mark Roth
 */

class Parser implements TagConstants {

    private ParserController parserController;
    private JspCompilationContext ctxt;
    private JspReader reader;
    private String currentFile;
    private Mark start;
    private ErrorDispatcher err;
    private int scriptlessCount;
    private boolean isTagFile;
    private boolean directivesOnly;
    private URL jarFileUrl;
    private PageInfo pageInfo;

    // Virtual body content types, to make parsing a little easier.
    // These are not accessible from outside the parser.
    private static final String JAVAX_BODY_CONTENT_PARAM = 
        "JAVAX_BODY_CONTENT_PARAM";
    private static final String JAVAX_BODY_CONTENT_PLUGIN = 
        "JAVAX_BODY_CONTENT_PLUGIN";
    private static final String JAVAX_BODY_CONTENT_TEMPLATE_TEXT = 
        "JAVAX_BODY_CONTENT_TEMPLATE_TEXT";

    /**
     * The constructor
     */
    private Parser(ParserController pc, JspReader reader, boolean isTagFile,
		   boolean directivesOnly, URL jarFileUrl) {
	this.parserController = pc;
	this.ctxt = pc.getJspCompilationContext();
	this.pageInfo = pc.getCompiler().getPageInfo();
	this.err = pc.getCompiler().getErrorDispatcher();
	this.reader = reader;
	this.currentFile = reader.mark().getFile();
        this.scriptlessCount = 0;
	this.isTagFile = isTagFile;
	this.directivesOnly = directivesOnly;
	this.jarFileUrl = jarFileUrl;
        start = reader.mark();
    }

    /**
     * The main entry for Parser
     * 
     * @param pc The ParseController, use for getting other objects in compiler
     *		 and for parsing included pages
     * @param reader To read the page
     * @param parent The parent node to this page, null for top level page
     * @return list of nodes representing the parsed page
     */
    public static Node.Nodes parse(ParserController pc,
				   JspReader reader,
				   Node parent,
				   boolean isTagFile,
				   boolean directivesOnly,
				   URL jarFileUrl,
				   String pageEnc,
				   String jspConfigPageEnc,
				   boolean isDefaultPageEncoding)
		throws JasperException {

	Parser parser = new Parser(pc, reader, isTagFile, directivesOnly,
				   jarFileUrl);

	Node.Root root = new Node.Root(reader.mark(), parent, false);
	root.setPageEncoding(pageEnc);
	root.setJspConfigPageEncoding(jspConfigPageEnc);
	root.setIsDefaultPageEncoding(isDefaultPageEncoding);

	if (directivesOnly) {
	    parser.parseTagFileDirectives(root);
	    return new Node.Nodes(root);
	}

	// For the Top level page, add inlcude-prelude and include-coda
	PageInfo pageInfo = pc.getCompiler().getPageInfo();
	if (parent == null) {
	    parser.addInclude(root, pageInfo.getIncludePrelude());
	}
	while (reader.hasMoreInput()) {
	    parser.parseElements(root);
	}
	if (parent == null) {
	    parser.addInclude(root, pageInfo.getIncludeCoda());
	}

	Node.Nodes page = new Node.Nodes(root);
	return page;
    }

    /**
     * Attributes ::= (S Attribute)* S?
     */
    Attributes parseAttributes() throws JasperException {
	AttributesImpl attrs = new AttributesImpl();

	reader.skipSpaces();
	while (parseAttribute(attrs))
	    reader.skipSpaces();

	return attrs;
    }

    /**
     * Parse Attributes for a reader, provided for external use
     */
    public static Attributes parseAttributes(ParserController pc,
					     JspReader reader)
		throws JasperException {
	Parser tmpParser = new Parser(pc, reader, false, false, null);
	return tmpParser.parseAttributes();
    }

    /**
     * Attribute ::= Name S? Eq S?
     *               (   '"<%=' RTAttributeValueDouble
     *                 | '"' AttributeValueDouble
     *                 | "'<%=" RTAttributeValueSingle
     *                 | "'" AttributeValueSingle
     *               }
     * Note: JSP and XML spec does not allow while spaces around Eq.  It is
     * added to be backward compatible with Tomcat, and with other xml parsers.
     */
    private boolean parseAttribute(AttributesImpl attrs)
	        throws JasperException {

	// Get the qualified name
	String qName = parseName();
	if (qName == null)
	    return false;

	// Determine prefix and local name components
	String localName = qName;
	String uri = "";
	int index = qName.indexOf(':');
	if (index != -1) {
	    String prefix = qName.substring(0, index);
	    uri = pageInfo.getURI(prefix);
	    if (uri == null) {
		err.jspError(reader.mark(),
			     "jsp.error.attribute.invalidPrefix", prefix);
	    }
	    localName = qName.substring(index+1);
	}

 	reader.skipSpaces();
	if (!reader.matches("="))
	    err.jspError(reader.mark(), "jsp.error.attribute.noequal");

 	reader.skipSpaces();
	char quote = (char) reader.nextChar();
	if (quote != '\'' && quote != '"')
	    err.jspError(reader.mark(), "jsp.error.attribute.noquote");

 	String watchString = "";
	if (reader.matches("<%="))
	    watchString = "%>";
	watchString = watchString + quote;
	
	String attrValue = parseAttributeValue(watchString);
	attrs.addAttribute(uri, localName, qName, "CDATA", attrValue);
	return true;
    }

    /**
     * Name ::= (Letter | '_' | ':') (Letter | Digit | '.' | '_' | '-' | ':')*
     */
    private String parseName() throws JasperException {
	char ch = (char)reader.peekChar();
	if (Character.isLetter(ch) || ch == '_' || ch == ':') {
	    StringBuffer buf = new StringBuffer();
	    buf.append(ch);
	    reader.nextChar();
	    ch = (char)reader.peekChar();
	    while (Character.isLetter(ch) || Character.isDigit(ch) ||
			ch == '.' || ch == '_' || ch == '-' || ch == ':') {
		buf.append(ch);
		reader.nextChar();
		ch = (char) reader.peekChar();
	    }
	    return buf.toString();
	}
	return null;
    }

    /**
     * AttributeValueDouble ::= (QuotedChar - '"')*
     *				('"' | <TRANSLATION_ERROR>)
     * RTAttributeValueDouble ::= ((QuotedChar - '"')* - ((QuotedChar-'"')'%>"')
     *				  ('%>"' | TRANSLATION_ERROR)
     */
    private String parseAttributeValue(String watch) throws JasperException {
	Mark start = reader.mark();
	Mark stop = reader.skipUntilIgnoreEsc(watch);
	if (stop == null) {
	    err.jspError(start, "jsp.error.attribute.unterminated", watch);
	}

	String ret = parseQuoted(reader.getText(start, stop));
	if (watch.length() == 1)	// quote
	    return ret;

	// putback delimiter '<%=' and '%>', since they are needed if the
	// attribute does not allow RTexpression.
	return "<%=" + ret + "%>";
    }

    /**
     * QuotedChar ::=   '&apos;'
     *	              | '&quot;'
     *                | '\\'
     *                | '\"'
     *                | "\'"
     *                | '\>'
     *                | '\$'
     *                | Char
     */
    private String parseQuoted(String tx) {
	StringBuffer buf = new StringBuffer();
	int size = tx.length();
	int i = 0;
	while (i < size) {
	    char ch = tx.charAt(i);
	    if (ch == '&') {
		if (i+5 < size && tx.charAt(i+1) == 'a'
		        && tx.charAt(i+2) == 'p' && tx.charAt(i+3) == 'o'
		        && tx.charAt(i+4) == 's' && tx.charAt(i+5) == ';') {
		    buf.append('\'');
		    i += 6;
		} else if (i+5 < size && tx.charAt(i+1) == 'q'
			   && tx.charAt(i+2) == 'u' && tx.charAt(i+3) == 'o'
			   && tx.charAt(i+4) == 't' && tx.charAt(i+5) == ';') {
		    buf.append('"');
		    i += 6;
		} else {
		    buf.append(ch);
		    ++i;
		}
	    } else if (ch == '\\' && i+1 < size) {
		ch = tx.charAt(i+1);
		if (ch == '\\' || ch == '\"' || ch == '\'' || ch == '>') {
		    buf.append(ch);
		    i += 2;
		} else if (ch == '$') {
		    // Replace "\$" with some special char.  XXX hack!
		    buf.append(Constants.ESC);
		    i += 2;
		} else {
		    buf.append('\\');
		    ++i;
		}
	    } else {
		buf.append(ch);
		++i;
	    }
	}
	return buf.toString();
    }

    private String parseScriptText(String tx) {
	CharArrayWriter cw = new CharArrayWriter();
	int size = tx.length();
	int i = 0;
	while (i < size) {
	    char ch = tx.charAt(i);
	    if (i+2 < size && ch == '%' && tx.charAt(i+1) == '\\'
		    && tx.charAt(i+2) == '>') {
		cw.write('%');
		cw.write('>');
		i += 3;
	    } else {
		cw.write(ch);
		++i;
	    }
	}
	cw.close();
	return cw.toString();
    }

    /*
     * Invokes parserController to parse the included page
     */
    private void processIncludeDirective(String file, Node parent) 
		throws JasperException {
	if (file == null) {
	    return;
	}

	try {
	    parserController.parse(file, parent, jarFileUrl);
	} catch (FileNotFoundException ex) {
	    err.jspError(start, "jsp.error.file.not.found", file);
	} catch (Exception ex) {
	    err.jspError(start, ex.getMessage());
	}
    }

    /*
     * Parses a page directive with the following syntax:
     *   PageDirective ::= ( S Attribute)*
     */
    private void parsePageDirective(Node parent) throws JasperException {
	Attributes attrs = parseAttributes();
	Node.PageDirective n = new Node.PageDirective(attrs, start, parent);

	/*
	 * A page directive may contain multiple 'import' attributes, each of
	 * which consists of a comma-separated list of package names.
	 * Store each list with the node, where it is parsed.
	 */
	for (int i = 0; i < attrs.getLength(); i++) {
	    if ("import".equals(attrs.getQName(i))) {
		n.addImport(attrs.getValue(i));
	    }
	}
    }

    /*
     * Parses an include directive with the following syntax:
     *   IncludeDirective ::= ( S Attribute)*
     */
    private void parseIncludeDirective(Node parent) throws JasperException {
	Attributes attrs = parseAttributes();

	// Included file expanded here
	Node includeNode = new Node.IncludeDirective(attrs, start, parent);
	processIncludeDirective(attrs.getValue("file"), includeNode);