parsercontroller.java

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	if (isExternal && !isXml) {
	    // JSP (standard) syntax. Use encoding specified in jsp-config
	    // if provided.
	    sourceEnc = jspConfigPageEnc;
	    if (sourceEnc != null) {
		return;
	    }
	    // We don't know the encoding
	    sourceEnc = "ISO-8859-1";
	} else {
	    // XML syntax or unknown, (auto)detect encoding ...
	    Object[] ret = XMLEncodingDetector.getEncoding(absFileName,
							   jarFile, ctxt, err);
	    sourceEnc = (String) ret[0];
	    if (((Boolean) ret[1]).booleanValue()) {
		isEncodingSpecifiedInProlog = true;
	    }

	    if (!isXml && sourceEnc.equals("UTF-8")) {
		/*
		 * We don't know if we're dealing with XML or standard syntax.
		 * Therefore, we need to check to see if the page contains
		 * a <jsp:root> element.
		 *
		 * We need to be careful, because the page may be encoded in
		 * ISO-8859-1 (or something entirely different), and may
		 * contain byte sequences that will cause a UTF-8 converter to
		 * throw exceptions. 
		 *
		 * It is safe to use a source encoding of ISO-8859-1 in this
		 * case, as there are no invalid byte sequences in ISO-8859-1,
		 * and the byte/character sequences we're looking for (i.e.,
		 * <jsp:root>) are identical in either encoding (both UTF-8
		 * and ISO-8859-1 are extensions of ASCII).
		 */
		sourceEnc = "ISO-8859-1";
		revert = true;
	    }
	}

	if (isXml) {
	    // (This implies 'isExternal' is TRUE.)
	    // We know we're dealing with a JSP document (via JSP config or
	    // ".jspx" suffix), so we're done.
	    return;
	}

	/*
	 * At this point, 'isExternal' or 'isXml' is FALSE.
	 * Search for jsp:root action, in order to determine if we're dealing 
	 * with XML or standard syntax (unless we already know what we're 
	 * dealing with, i.e., when 'isExternal' is TRUE and 'isXml' is FALSE).
	 * No check for XML prolog, since nothing prevents a page from
	 * outputting XML and still using JSP syntax (in this case, the 
	 * XML prolog is treated as template text).
	 */
	JspReader jspReader = null;
	try {
	    jspReader = new JspReader(ctxt, absFileName, sourceEnc, jarFile,
				      err);
	} catch (FileNotFoundException ex) {
	    throw new JasperException(ex);
	}
        jspReader.setSingleFile(true);
        Mark startMark = jspReader.mark();
	if (!isExternal) {
	    jspReader.reset(startMark);
	    if (hasJspRoot(jspReader)) {
	        isXml = true;
		if (revert) sourceEnc = "UTF-8";
		return;
	    } else {
	        isXml = false;
	    }
	}

	/*
	 * At this point, we know we're dealing with JSP syntax.
	 * If an XML prolog is provided, it's treated as template text.
	 * Determine the page encoding from the page directive, unless it's
	 * specified via JSP config.
	 */
	sourceEnc = jspConfigPageEnc;
	if (sourceEnc == null) {
	    sourceEnc = getPageEncodingForJspSyntax(jspReader, startMark);
	    if (sourceEnc == null) {
		// Default to "ISO-8859-1" per JSP spec
		sourceEnc = "ISO-8859-1";
		isDefaultPageEncoding = true;
	    }
	}
    }
    
    /*
     * Determines page source encoding for page or tag file in JSP syntax,
     * by reading (in this order) the value of the 'pageEncoding' page
     * directive attribute, or the charset value of the 'contentType' page
     * directive attribute.
     *
     * @return The page encoding, or null if not found
     */
    private String getPageEncodingForJspSyntax(JspReader jspReader,
					       Mark startMark)
	        throws JasperException {

	String encoding = null;
        String saveEncoding = null;

        jspReader.reset(startMark);

	/*
	 * Determine page encoding from directive of the form <%@ page %>,
	 * <%@ tag %>, <jsp:directive.page > or <jsp:directive.tag >.
	 */
        while (true) {
            if (jspReader.skipUntil("<") == null) {
                break;
            }
            // If this is a comment, skip until its end
            if (jspReader.matches("%--")) {
                if (jspReader.skipUntil("--%>") == null) {
                    // error will be caught in Parser
                    break;
                }
                continue;
            }
            boolean isDirective = jspReader.matches("%@");
            if (isDirective) {
	        jspReader.skipSpaces();
            }
            else {
                isDirective = jspReader.matches("jsp:directive.");
            }
            if (!isDirective) {
                continue;
            }

	    // compare for "tag ", so we don't match "taglib"
	    if (jspReader.matches("tag ") || jspReader.matches("page")) {

		jspReader.skipSpaces();
                Attributes attrs = Parser.parseAttributes(this, jspReader);
		encoding = getPageEncodingFromDirective(attrs, "pageEncoding");
                if (encoding != null) {
                    break;
                }
		encoding = getPageEncodingFromDirective(attrs, "contentType");
                if (encoding != null) {
                    saveEncoding = encoding;
                }
	    }
	}

        if (encoding == null) {
            encoding = saveEncoding;
        }

	return encoding;
    }

    /*
     * Scans the given attributes for the attribute with the given name,
     * which is either 'pageEncoding' or 'contentType', and returns the
     * specified page encoding.
     *
     * In the case of 'contentType', the page encoding is taken from the
     * content type's 'charset' component.
     *
     * @param attrs The page directive attributes
     * @param attrName The name of the attribute to search for (either
     * 'pageEncoding' or 'contentType')
     *
     * @return The page encoding, or null
     */
    private String getPageEncodingFromDirective(Attributes attrs,
                                                String attrName) {
	String value = attrs.getValue(attrName);
        if (attrName.equals("pageEncoding")) {
            return value;
        }

        // attrName = contentType
        String contentType = value;
        String encoding = null;
        if (contentType != null) {
	    int loc = contentType.indexOf(CHARSET);
	    if (loc != -1) {
		encoding = contentType.substring(loc + CHARSET.length());
	    }
	}

	return encoding;
    }

    /*
     * Resolve the name of the file and update baseDirStack() to keep track of
     * the current base directory for each included file.
     * The 'root' file is always an 'absolute' path, so no need to put an
     * initial value in the baseDirStack.
     */
    private String resolveFileName(String inFileName) {
        String fileName = inFileName.replace('\\', '/');
        boolean isAbsolute = fileName.startsWith("/");
	fileName = isAbsolute ? fileName 
            : (String) baseDirStack.peek() + fileName;
	String baseDir = 
	    fileName.substring(0, fileName.lastIndexOf("/") + 1);
	baseDirStack.push(baseDir);
	return fileName;
    }

    /*
     * Checks to see if the given page contains, as its first element, a <root>
     * element whose prefix is bound to the JSP namespace, as in:
     *
     * <wombat:root xmlns:wombat="http://java.sun.com/JSP/Page" version="1.2">
     *   ...
     * </wombat:root>
     *
     * @param reader The reader for this page
     *
     * @return true if this page contains a root element whose prefix is bound
     * to the JSP namespace, and false otherwise
     */
    private boolean hasJspRoot(JspReader reader) throws JasperException {

	// <prefix>:root must be the first element
	Mark start = null;
	while ((start = reader.skipUntil("<")) != null) {
	    int c = reader.nextChar();
	    if (c != '!' && c != '?') break;
	}
	if (start == null) {
	    return false;
	}
	Mark stop = reader.skipUntil(":root");
	if (stop == null) {
	    return false;
	}
	// call substring to get rid of leading '<'
	String prefix = reader.getText(start, stop).substring(1);

	start = stop;
	stop = reader.skipUntil(">");
	if (stop == null) {
	    return false;
	}

	// Determine namespace associated with <root> element's prefix
	String root = reader.getText(start, stop);
	String xmlnsDecl = "xmlns:" + prefix;
	int index = root.indexOf(xmlnsDecl);
	if (index == -1) {
	    return false;
	}
	index += xmlnsDecl.length();
	while (index < root.length()
	           && Character.isWhitespace(root.charAt(index))) {
	    index++;
	}
	if (index < root.length() && root.charAt(index) == '=') {
	    index++;
	    while (index < root.length()
		       && Character.isWhitespace(root.charAt(index))) {
		index++;
	    }
	    if (index < root.length() && root.charAt(index++) == '"'
		    && root.regionMatches(index, JSP_URI, 0,
					  JSP_URI.length())) {
		return true;
	    }
	}

	return false;
    }

    private JarFile getJarFile(URL jarFileUrl) throws IOException {
	JarFile jarFile = null;

	if (jarFileUrl != null) {
	    JarURLConnection conn = (JarURLConnection) jarFileUrl.openConnection();
	    conn.setUseCaches(false);
	    conn.connect();
	    jarFile = conn.getJarFile();
	}

	return jarFile;
    }

}