xincludefilter.java

gcc的组建

	URL	baseURI = (URL) uris.peek ();
	String	base;

	base = atts.getValue ("http://www.w3.org/XML/1998/namespace", "base");
	if (base == null)
	    uris.push (baseURI);
	else {
	    URL		url;

	    if (base.indexOf ('#') != -1)
		fatal (new SAXParseException (
		    "xml:base with fragment: " + base,
		    locator));

	    try {
		baseURI = new URL (baseURI, base);
		uris.push (baseURI);
	    } catch (Exception e) {
		fatal (new SAXParseException (
		    "xml:base with illegal uri: " + base,
		    locator, e));
	    }
	}

	if (!"http://www.w3.org/2001/XInclude".equals (uri)) {
	    super.startElement (uri, localName, qName, atts);
	    return;
	}

	if ("include".equals (localName)) {
	    String	href = atts.getValue ("href");
	    String	parse = atts.getValue ("parse");
	    String	encoding = atts.getValue ("encoding");
	    URL		url = (URL) uris.peek ();
	    SAXParseException	x = null;

	    if (href == null)
		fatal (new SAXParseException (
		    "XInclude missing href",
		    locator));
	    if (href.indexOf ('#') != -1)
		fatal (new SAXParseException (
		    "XInclude with fragment: " + href,
		    locator));

	    if (parse == null || "xml".equals (parse))
		x = xinclude (url, href);
	    else if ("text".equals (parse))
		x = readText (url, href, encoding);
	    else
		fatal (new SAXParseException (
		    "unknown XInclude parsing mode: " + parse,
		    locator));
	    if (x == null) {
		// strip out all child content
		ignoreCount++;
		return;
	    }

	    // FIXME the 17-Sept-2002 CR of XInclude says we "must"
	    // use xi:fallback elements to handle resource errors,
	    // if they exist.
	    fatal (x);

	} else if ("fallback".equals (localName)) {
	    fatal (new SAXParseException (
		"illegal top level XInclude 'fallback' element",
		locator));
	} else {
	    ErrorHandler	eh = getErrorHandler ();

	    // CR doesn't say this is an error
	    if (eh != null)
		eh.warning (new SAXParseException (
		    "unrecognized toplevel XInclude element: " + localName,
		    locator));
	    super.startElement (uri, localName, qName, atts);
	}
    }

    public void endElement (String uri, String localName, String qName)
    throws SAXException
    {
	if (ignoreCount != 0) {
	    if (--ignoreCount != 0)
		return;
	}

	uris.pop ();
	if (!("http://www.w3.org/2001/XInclude".equals (uri)
		&& "include".equals (localName)))
	    super.endElement (uri, localName, qName);
    }

    //
    // ignore all content within non-empty xi:include elements
    //
    public void characters (char ch [], int start, int length)
    throws SAXException
    {
	if (ignoreCount == 0)
	    super.characters (ch, start, length);
    }

    public void processingInstruction (String target, String value)
    throws SAXException
    {
	if (ignoreCount == 0)
	    super.processingInstruction (target, value);
    }

    public void ignorableWhitespace (char ch [], int start, int length)
    throws SAXException
    {
	if (ignoreCount == 0)
	    super.ignorableWhitespace (ch, start, length);
    }

    public void comment (char ch [], int start, int length)
    throws SAXException
    {
	if (ignoreCount == 0)
	    super.comment (ch, start, length);
    }

    public void startCDATA () throws SAXException
    {
	if (ignoreCount == 0)
	    super.startCDATA ();
    }

    public void endCDATA () throws SAXException
    {
	if (ignoreCount == 0)
	    super.endCDATA ();
    }

    public void startPrefixMapping (String prefix, String uri)
    throws SAXException
    {
	if (ignoreCount == 0)
	    super.startPrefixMapping (prefix, uri);
    }

    public void endPrefixMapping (String prefix) throws SAXException
    {
	if (ignoreCount == 0)
	    super.endPrefixMapping (prefix);
    }

    public void skippedEntity (String name) throws SAXException
    {
	if (ignoreCount == 0)
	    super.skippedEntity (name);
    }

    // JDK 1.1 seems to need it to be done this way, sigh
    void setLocator (Locator l) { locator = l; }
    Locator getLocator () { return locator; }
    

    //
    // for XIncluded entities, manage the current locator and
    // filter out events that would be incorrect to report
    //
    private class Scrubber extends EventFilter
    {
	Scrubber (EventFilter f)
	throws SAXException
	{
	    // delegation passes to next in chain
	    super (f);

	    // process all content events
	    super.setContentHandler (this);
	    super.setProperty (LEXICAL_HANDLER, this);

	    // drop all DTD events
	    super.setDTDHandler (null);
	    super.setProperty (DECL_HANDLER, null);
	}

	// maintain proxy locator
	// only one startDocument()/endDocument() pair per event stream
	public void setDocumentLocator (Locator l)
	    { setLocator (l); }
	public void startDocument ()
	    { }
	public void endDocument ()
	    { }
	
	private void reject (String message) throws SAXException
	    { fatal (new SAXParseException (message, getLocator ())); }
	
	// only the DTD from the "base document" gets reported
	public void startDTD (String root, String publicId, String systemId)
	throws SAXException
	    { reject ("XIncluded DTD: " + systemId); }
	public void endDTD ()
	throws SAXException
	    { reject ("XIncluded DTD"); }
	// ... so this should never happen
	public void skippedEntity (String name) throws SAXException
	    { reject ("XInclude skipped entity: " + name); }

	// since we rejected DTDs, only builtin entities can be reported
    }

    // <xi:include parse='xml' ...>
    // relative to the base URI passed
    private SAXParseException xinclude (URL url, String href)
    throws SAXException
    {
	XMLReader	helper;
	Scrubber	scrubber;
	Locator		savedLocator = locator;

	// start with a parser acting just like our input
	// modulo DTD-ish stuff (validation flag, entity resolver)
	helper = XMLReaderFactory.createXMLReader ();
	helper.setErrorHandler (getErrorHandler ());
	helper.setFeature (FEATURE_URI + "namespace-prefixes", true);

	// Set up the proxy locator and event filter.
	scrubber = new Scrubber (this);
	locator = null;
	bind (helper, scrubber);

	// Merge the included document, except its DTD
	try {
	    url = new URL (url, href);
	    href = url.toString ();

	    if (inclusions.contains (href))
		fatal (new SAXParseException (
			"XInclude, circular inclusion", locator));

	    inclusions.addElement (href);
	    uris.push (url);
	    helper.parse (new InputSource (href));
	    return null;
	} catch (java.io.IOException e) {
	    return new SAXParseException (href, locator, e);
	} finally {
	    pop (href);
	    locator = savedLocator;
	}
    }

    // <xi:include parse='text' ...>
    // relative to the base URI passed
    private SAXParseException readText (URL url, String href, String encoding)
    throws SAXException
    {
	InputStream	in = null;

	try {
	    URLConnection	conn;
	    InputStreamReader	reader;
	    char		buf [] = new char [4096];
	    int			count;

	    url = new URL (url, href);
	    conn = url.openConnection ();
	    in = conn.getInputStream ();
	    if (encoding == null)
		encoding = Resolver.getEncoding (conn.getContentType ());
	    if (encoding == null) {
		ErrorHandler	eh = getErrorHandler ();
		if (eh != null)
		    eh.warning (new SAXParseException (
			"guessing text encoding for URL: " + url,
			locator));
		reader = new InputStreamReader (in);
	    } else
		reader = new InputStreamReader (in, encoding);

	    while ((count = reader.read (buf, 0, buf.length)) != -1)
		super.characters (buf, 0, count);
	    in.close ();
	    return null;
	} catch (IOException e) {
	    return new SAXParseException (
		"can't XInclude text",
		locator, e);
	}
    }
}