/*
 * Resolver.java
 * :folding=explicit:collapseFolds=1:
 *
 * Copyright (C) 2006 Alan Ezust
 * Portions Copyright (C) 2007 hertzhaft
 * Copyright (C) 2009 Eric Le Lay
 *
 * The XML plugin is licensed under the GNU General Public License, with
 * the following exception:
 *
 * "Permission is granted to link this code with software released under
 * the Apache license version 1.1, for example used by the Xerces XML
 * parser package."
 */
package xml;

//{{{ imports
import java.awt.Component;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.io.Reader;
import java.net.URL;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.StringReader;
import java.util.HashMap;
import java.util.Iterator;
import java.util.HashSet;
import java.util.Set;

import javax.swing.JOptionPane;
import javax.swing.SwingUtilities;

import org.apache.xml.resolver.Catalog;

import org.gjt.sp.jedit.EditBus;
import org.gjt.sp.jedit.EBComponent;
import org.gjt.sp.jedit.EBMessage;
import org.gjt.sp.jedit.Buffer;
import org.gjt.sp.jedit.GUIUtilities;
import org.gjt.sp.jedit.MiscUtilities;
import org.gjt.sp.jedit.View;
import org.gjt.sp.jedit.jEdit;
import org.gjt.sp.jedit.io.VFS;
import org.gjt.sp.jedit.io.VFSManager;
import org.gjt.sp.jedit.msg.VFSUpdate;
import org.gjt.sp.util.Log;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.ext.EntityResolver2;

// for jaxp
import org.w3c.dom.ls.LSResourceResolver;
import org.w3c.dom.ls.LSInput;

import static xml.Debug.*;
import xml.PathUtilities;
// }}}

/**
 * Resolver grabs and caches DTDs and xml schemas.
 * It also serves as a resource resolver for jeditresource: links
 *
 * @author ezust
 * @author kerik-sf
 * @version $Id: Resolver.java 18426 2010-08-27 06:42:52Z kerik-sf $
 *
 */
public class Resolver implements EntityResolver2, LSResourceResolver
{

	/** Ask before downloading */
	public static final String ASK = "ask";
	/** Local files & catalogs only */
	public static final String LOCAL = "local";
	/** Download without asking */
	public static final String ALWAYS = "always";
	public static final String MODES[] = new String[] {ASK, LOCAL, ALWAYS};
	private boolean loadedCache = false;
	private boolean loadedCatalogs = false;
	public static final String NETWORK_PROPS = "xml.general.network";


	//{{{ Package-private members

	//{{{ init() method
	void init()
	{
		// TODO: not sure about this handler : is it useful ?
		EditBus.addToBus(vfsUpdateHandler = new VFSUpdateHandler());
	} //}}}

	//{{{ uninit() method
	void uninit()
	{
		EditBus.removeFromBus(vfsUpdateHandler);
		// really forget current state
		singleton = null;
	} //}}}

	//{{{ save() method
	public void save()
	{
		if(loadedCache)
		{
			int systemCount = 0;
			int publicCount = 0;

			Iterator keys = resourceCache.keySet().iterator();
			while(keys.hasNext())
			{
				Entry entry = (Entry)keys.next();
				Object uri = resourceCache.get(entry);
				if(uri == IGNORE)
					continue;

				if(entry.type == Entry.PUBLIC)
				{
					jEdit.setProperty("xml.cache.public-id." + publicCount,entry.id);
					jEdit.setProperty("xml.cache.public-id." + publicCount
						+ ".uri",uri.toString());
					publicCount++;
				}
				else
				{
					jEdit.setProperty("xml.cache.system-id." + systemCount,entry.id);
					jEdit.setProperty("xml.cache.system-id." + systemCount
						+ ".uri",uri.toString());
					systemCount++;
				}
			}

			jEdit.unsetProperty("xml.cache.public-id." + publicCount);
			jEdit.unsetProperty("xml.cache.public-id." + publicCount + ".uri");
			jEdit.unsetProperty("xml.cache.system-id." + systemCount);
			jEdit.unsetProperty("xml.cache.system-id." + systemCount + ".uri");
		}
	} //}}}
	//}}}

	/**
	 * Ask before downloading remote files
	 */
	public static final String MODE = NETWORK_PROPS + ".mode";
	/**
	 * Cache downloaded remote files
	 */
	public static final String CACHE = NETWORK_PROPS + ".cache";

	// {{{ static variables
	/** Internal catalog for DTDs which are packaged in
	 * XML.jar and jEdit.jar */
	public static final String INTERNALCATALOG =
		"jeditresource:/XML.jar!/xml/dtds/catalog";
	//a String : type-safety of the collection
	private static String IGNORE = new String("IGNORE");
	private static Resolver singleton = null;
	private static String resourceDir;

	// }}}

	// {{{ Instance Variables
	private EBComponent vfsUpdateHandler;
	/** Internal catalog for DTDs which are packaged in
	 * XML.jar and jEdit.jar
	   Parses and manages the catalog files
	   Moved away from Xerces' XMLCatalogResolver,
	   as it's really an overlay on top of commons-resolver
	   and it supports less catalog formats than commons-resolver
	   */
	private Catalog catalog = null;

	/** Mapping from public ID to URLs */
	private HashMap<Entry,String> resourceCache;

	/** Set of catalog files to load.
	 *  A set is used to remove duplicates (either via symlinks or double entry by the user)
	 */
	private Set<String> catalogFiles;



	// }}}

	// {{{ instance()

	/**
	 *
	 * @return a global catalog resolver object you can use as an
	 * LSResourceResolver or EntityResolver.
	 */
	public static synchronized Resolver instance() {
		if (singleton == null) {
			jEdit.getPlugin(xml.XmlPlugin.class.getName()).getPluginJAR().activatePlugin();
			singleton = new Resolver();
			singleton.init();
			singleton.load();
		}

		return singleton;
	}
	// }}}

	/**
	 * You can't create an object directly.
	 * use @ref instance() to get a singleton instance.
	 *
	 */
	private Resolver() {
	}

	// {{{ - load()
	private synchronized void load()
	{
		if(!loadedCache)
		{

			resourceCache = new HashMap<Entry,String>();
			if (isUsingCache())

			{
				resourceDir = MiscUtilities.constructPath(
					jEdit.getSettingsDirectory(),"dtds");

			}

			int i;
			String id, prop, uri;

			i = 0;
			while((id = jEdit.getProperty(prop = "xml.cache"
				+ ".public-id." + i++)) != null)
			{
				uri = jEdit.getProperty(prop + ".uri");
				resourceCache.put(new Entry(Entry.PUBLIC,id,uri),uri);
			}

			i = 0;
			while((id = jEdit.getProperty(prop = "xml.cache"
				+ ".system-id." + i++)) != null)
			{
				uri = jEdit.getProperty(prop + ".uri");
				Entry se = new Entry(Entry.SYSTEM,id,uri);
				resourceCache.put(se,uri);
				if(DEBUG_RESOLVER)Log.log(Log.DEBUG,Resolver.class, "loading cache "+id+" -> "+uri);
			}
			loadedCache = true;
		}
		if (!loadedCatalogs) {
			loadedCatalogs = true;

			catalog = new Catalog();
			catalog.getCatalogManager().setPreferPublic(true);
			// don't issue an error "Cannot find CatalogManager.properties"
			// fix for plugin bug #1090658 - XML plugin can't find CatalogManager.properties
			// warning: this will also suppress warnings if somebody adds a CatalogManager.properties
			// and references non-existing catalogs
			catalog.getCatalogManager().ignoreMissingProperties(!DEBUG_RESOLVER);
			// verbosity to 2 lists which catalogs are loaded and syntax errors
			// it seems a reasonable default
			catalog.getCatalogManager().setVerbosity(DEBUG_RESOLVER?Integer.MAX_VALUE:2);
			catalog.setupReaders();
			catalogFiles = new HashSet<String>();
			catalogFiles.add(INTERNALCATALOG);

			try
			{
				if(DEBUG_RESOLVER)Log.log(Log.MESSAGE,Resolver.class,
						"Loading system catalogs");
				catalog.loadSystemCatalogs();
				if(DEBUG_RESOLVER)Log.log(Log.MESSAGE,Resolver.class,
						"Loading internal catalog: " + INTERNALCATALOG);
				catalog.parseCatalog(INTERNALCATALOG);
			}
			catch(Exception ex1){
				Log.log(Log.ERROR,Resolver.class,ex1);
			}


			int i = 0;
			String uri = null;
			do {
				String prop = "xml.catalog." + i++;
				uri = jEdit.getProperty(prop);
				if (uri == null) break;

				if(DEBUG_RESOLVER)Log.log(Log.DEBUG,Resolver.class,
						"Loading catalog: " + uri);

				if(MiscUtilities.isURL(uri))
					catalogFiles.add(uri);
				else
					catalogFiles.add(MiscUtilities.resolveSymlinks(uri));

				try
				{
						catalog.parseCatalog(uri);
				}
				catch(Exception ex2)
				{
					ex2.printStackTrace();
					Log.log(Log.ERROR,Resolver.class,ex2);
				}


			} while (uri != null);

		}


	} //}}}

	//{{{ implements LSResourceResolver
	public LSInput resolveResource(String type, String namespaceURI, String publicId, String systemId, String baseURI)
	{
		if(DEBUG_RESOLVER)Log.log(Log.DEBUG,Resolver.class,"resolveResource("+type+","+namespaceURI+","+publicId+","+systemId+","+baseURI);
		try{
			InputSource is = resolveEntity(type,publicId,baseURI,systemId);
			if(is == null)return null;
			else return new InputSourceAsLSInput(is);
		}catch(SAXException e){
			throw new RuntimeException("Error loading resource "+systemId,e);
			//maybe return null
		}catch(IOException e){
			throw new RuntimeException("Error loading resource "+systemId,e);
			//maybe return null
		}
	}
	
	/**
	 * wrapper arround an InputSource for DOM2 Load and Save,
	 * needed to implement LSResourceResolver for javax.xml.validation.SchemaFactory.
	 * No setter method is active.
	 * Maybe this should be the other way round : implement natively LSResourceResolver
	 * and wrap an LSInput as InputSource...
	 */
	private static class InputSourceAsLSInput implements LSInput{
		private InputSource is;
		
		InputSourceAsLSInput(InputSource is)
		{
			this.is = is;
		}
		
		public String getBaseURI()
		{
			return null;
		}
		
		public InputStream getByteStream(){
			return is.getByteStream();
		}
		
		public boolean getCertifiedText(){
			return false;
		}
		
        public Reader getCharacterStream(){
        	return is.getCharacterStream();
        }
        public String getEncoding(){
        	return is.getEncoding();
        }
        public String getPublicId(){
        	return is.getPublicId();
        }
        public String getStringData(){
        	return null;
        }
        public String getSystemId(){
        	return is.getSystemId();
        }
        
        /**
         * @throws UnsupportedOperationException no setter !
         */
        public void setBaseURI(String baseURI)
        {
        	throw new UnsupportedOperationException("setBaseURI()");
        }

        /**
         * @throws UnsupportedOperationException no setter !
         */
        public void setByteStream(InputStream byteStream)
        {
        	throw new UnsupportedOperationException("setByteStream()");
        }

        /**
         * @throws UnsupportedOperationException no setter !
         */
        public void setCertifiedText(boolean certifiedText)
        {
        	throw new UnsupportedOperationException("setCertifiedText()");
        }

        /**
         * @throws UnsupportedOperationException no setter !
         */
        public void setCharacterStream(Reader characterStream)
        {
        	throw new UnsupportedOperationException("setCharacterStream()");
        }

        /**
         * @throws UnsupportedOperationException no setter !
         */
        public void setEncoding(String encoding)
        {
        	throw new UnsupportedOperationException("setEncoding()");
        }

        /**
         * @throws UnsupportedOperationException no setter !
         */
        public void setPublicId(String publicId)
        {
        	throw new UnsupportedOperationException("setPublicId()");
        }

        /**
         * @throws UnsupportedOperationException no setter !
         */
        public void setStringData(String stringData)
        {
        	throw new UnsupportedOperationException("setStringData()");
        }

        /**
         * @throws UnsupportedOperationException no setter !
         */
        public void setSystemId(String systemId)
        {
        	throw new UnsupportedOperationException("setSystemId()");
        }
	}
	// }}}
	
	// {{{ resolveEntity

	/** implements SAX1 EntityResolver
	 * @see org.xml.sax.ext.DefaultHandler2#resolveEntity(java.lang.String, java.lang.String)
	 */
	public InputSource resolveEntity(String publicId, String systemId) throws SAXException, IOException
	{
		if(DEBUG_RESOLVER)Log.log(Log.DEBUG,Resolver.class,"simple resolveEntity("+publicId+","+systemId+")");
		return resolveEntity(null, publicId, null, systemId);
	}

	/**
	 * @param name
	 * @param publicId
	 * @param current
	 * @param systemId
	 */
	public String resolveEntityToPath(String name, String publicId, String current,
		String systemId) throws java.io.IOException {
		String[]res =resolveEntityToPathInternal(name,publicId,current,systemId);
		if(res == null)return null;
		else return res[1];
	}
	
	/**
	 * systemId may be modified, for instance if resolving docbookx.dtd, 
	 * the systemId  will be the full jeditresource:XML.jar!.../docbookx.dtd
	 * @return array [systemId to report, real systemId]
	 */
	private String[] resolveEntityToPathInternal(String name, String publicId, String current,
		String systemId) throws java.io.IOException {
		
		if(publicId != null && publicId.length() == 0)
			publicId = null;

		if(systemId != null && systemId.length() == 0)
			systemId = null;

		String newSystemId = null;

		if(DEBUG_RESOLVER)Log.log(Log.DEBUG,Resolver.class,"Resolver.resolveEntity("+name+","+publicId+","+current+","+systemId+")");

		//catch an error message here
		if(publicId == null && systemId == null)return null;

		String parent;
		if(current != null)
		{
			parent = MiscUtilities.getParentOfPath(current);
		}
		else
			parent = null;

		// try the catalog 
		if(publicId == null)
			newSystemId = resolvePublicOrSystem(systemId,false);
		else
		{
			newSystemId = resolvePublicOrSystem(publicId,true);
			if(newSystemId == null && systemId != null){
				//try the systemId as a backup 
				// calling again resolvePublicOrSystem in case
				// the systemId is in cache
				newSystemId = resolvePublicOrSystem(systemId,false);
			}
		}

		// well, the catalog can't help us, so just assume the
		// system id points to a file or URL
		if(newSystemId == null)
		{
			// had a public Id, but catalog returned null
			if(systemId == null)
				return null;
			// succeeds if it's a fully qualified url :
			// "http://www.jedit.org" succeeds,  "../test.txt" fails
			else if(MiscUtilities.isURL(systemId))
				newSystemId = systemId;
			else
			{
				
				// systemId is absolute or no parent, use systemId
				if(new File(systemId).isAbsolute() || parent == null)
				{
					newSystemId = systemId;
				}
				// systemId is relative, use parent
				//need this to resolve xinclude.mod from user-guide.xml
				else
				{
					if(DEBUG_RESOLVER)Log.log(Log.DEBUG,Resolver.class,"using parent !");
					newSystemId = parent + systemId;
					// set the systemId, overwise jing has trouble opening the file
					// FIXME: apply this fix for over kinds of resources
					systemId = newSystemId;
				}
				
				// when resolving "../simple/actions.xsd" from test_data/schema_loader/actions.xml
				// insert file:// at the begining
				if(!MiscUtilities.isURL(newSystemId))
				{
					try{
						newSystemId = new File(newSystemId).toURI().toURL().toString();;
						//set it, otherwise it will never get a sound system id
						systemId = newSystemId;
					}catch(java.net.MalformedURLException mue){
						//too bad, try something else
					}
				}
			}
		}

		// don't throw the IOException, as we don't have a
		// meaningful message to display to the user
		if(newSystemId == null)
			return null;
		
		// prevent the dialog from always poping-up when viewing
		// https://jedit.svn.sourceforge.net/svnroot/jedit/plugins/XML/trunk/test_data/dir%20with%20space/actions.xsd
		String lastChance = resolvePublicOrSystemFromCache(newSystemId,false);
		if(lastChance != null && lastChance != IGNORE){
			if(DEBUG_RESOLVER)Log.log(Log.DEBUG,Resolver.class,"was going to fetch it again !");
			newSystemId = lastChance;
		}
		
		return new String[]{systemId,newSystemId};
	}

	public InputSource resolveEntity(String name, String publicId, String current,
		String systemId) throws SAXException, java.io.IOException
	{

		String[] sids = resolveEntityToPathInternal(name,publicId,current,systemId);
		if(sids == null)return null;
		else return openEntity(name, publicId, current,sids[0],sids[1]);
	}
	
	/** open an already resolved Entity.
	  * Not public because the systemId may have to be changed (see result of resolveEntityToPathInternal)
	  */
	private InputSource openEntity(String name, String publicId, String current,
		String systemId,String newSystemId) throws SAXException, java.io.IOException
	{
		// don't throw the IOException, as we don't have a
		// meaningful message to display to the user
		if(newSystemId == null)
			return null;

		Buffer buf = jEdit.getBuffer(PathUtilities.urlToPath(newSystemId));
		if(buf != null)
		{
			if(buf.isPerformingIO())
				VFSManager.waitForRequests();
			if(DEBUG_RESOLVER)Log.log(Log.DEBUG, getClass(), "Found open buffer for " + newSystemId);
			InputSource source = new InputSource(publicId);
			//use the original systemId
			source.setSystemId(systemId);
			try
			{
				buf.readLock();
				source.setCharacterStream(new StringReader(buf.getText(0,
					buf.getLength())));
			}
			finally
			{
				buf.readUnlock();
			}
			return source;
		}
		else if(newSystemId.startsWith("file:")
			|| newSystemId.startsWith("jar:file:")
			|| newSystemId.startsWith("jeditresource:"))
		{
			// don't keep a relative URL such as locate.rng
			if(newSystemId.startsWith("jeditresource:")){
				systemId=newSystemId;
			}
			// pretend to be reading the file from whatever the systemId was
			// eg. http://slackerdoc.tigris.org/xsd/slackerdoc.xsd when we
			// are reading ~/.jedit/dtds/cache1345.xml
			if(DEBUG_RESOLVER)
			{
				Log.log(Log.DEBUG,Resolver.class,"resolving to local file: "+newSystemId);
				Log.log(Log.DEBUG,Resolver.class,"systemId=: "+systemId);
			}
			InputSource source = new InputSource(systemId);
			source.setPublicId(publicId);
			InputStream is = new URL(newSystemId).openStream();
			source.setByteStream(is);
			return source;
		}
		else if (LOCAL.equals(getNetworkMode()))
		{
			if(DEBUG_RESOLVER)Log.log(Log.DEBUG,Resolver.class,"refusing to fetch remote entity (configured for Local-only)");
			// returning null would not be as informing
			// TODO: prevent the 'premature end of file' error from showing
			throw new IOException(jEdit.getProperty("xml.network.error"));
		}
		else
		{
			final String _newSystemId = newSystemId;
			final VFS vfs = VFSManager.getVFSForPath(_newSystemId);
			// use a final array to pass a mutable value from the
			// invokeAndWait() call
			final Object[] sessionArray = new Object[1];
			Runnable run = new Runnable()
			{
				public void run()
				{
					View view = jEdit.getActiveView();
					if (ALWAYS.equals(getNetworkMode())
                        || (ASK.equals(getNetworkMode())
                            && showDownloadResourceDialog(view,_newSystemId))
                        )
					{
						sessionArray[0] = vfs.createVFSSession(
							_newSystemId,view);
					}
				}
			};

			if(SwingUtilities.isEventDispatchThread())
				run.run();
			else
			{
				try
				{
					SwingUtilities.invokeAndWait(run);
				}
				catch(Exception e)
				{
					throw new RuntimeException(e);
				}
			}
			Object session = sessionArray[0];
			if(session != null)
			{
				InputSource source = new InputSource(systemId);
				source.setPublicId(publicId);
				if(isUsingCache())
				{
					File file;
					try
					{
						file = copyToLocalFile(session,vfs,newSystemId);
					}
					finally
					{
						vfs._endVFSSession(session,null);
					}

					addUserResource(publicId,systemId,file.toURL().toString());
					source.setByteStream(new FileInputStream(file));
				}
				else
					source.setByteStream(vfs._createInputStream(session,newSystemId,false,null));

				if(DEBUG_RESOLVER)
				{
					Log.log(Log.DEBUG,Resolver.class,"resolving to remote file: "+newSystemId);
					Log.log(Log.DEBUG,Resolver.class,"systemId=: "+systemId);
				}
				return source;
			}
			else
			{
				// returning null would not be as informing
				// TODO: prevent the 'premature end of file' error from showing
				throw new IOException(jEdit.getProperty("xml.network.error"));
			}
		}

	} //}}}

	// {{{ clearCache
	public void clearCache()
	{


		Iterator files = resourceCache.values().iterator();
		while(files.hasNext())
		{
			Object obj = files.next();
			if(obj instanceof String)
			{
				String file = (String)PathUtilities.urlToPath((String)obj);
				Log.log(Log.NOTICE, getClass(), "Deleting " + file);
				new File(file).delete();
			}
		}

		//clear the properties !
		int i=0;
		String prop;
		while(jEdit.getProperty(prop = "xml.cache"
			+ ".public-id." + i++) != null)
		{
			System.out.println("unset "+prop);
			jEdit.unsetProperty(prop);
			jEdit.unsetProperty(prop+".uri");
		}

		i = 0;
		while(jEdit.getProperty(prop = "xml.cache"
			+ ".system-id." + i++) != null)
		{
			System.out.println("unset "+prop);
			jEdit.unsetProperty(prop);
			jEdit.unsetProperty(prop+".uri");
		}

		resourceCache.clear();
	} //}}}

	/**
	 * called from actions.xml
	 */
	public synchronized void reloadCatalogs()
	{
		loadedCatalogs = false;
		load();
	}
	
	private String resolvePublicOrSystemFromCache(String id, boolean isPublic){
		Entry e = new Entry(isPublic ? Entry.PUBLIC : Entry.SYSTEM,id,null);
		if(DEBUG_RESOLVER)Log.log(Log.DEBUG,Resolver.class,"resolvePublicOrSystemFromCache("+id+")");
		String uri = resourceCache.get(e);
		
		if(DEBUG_RESOLVER)
		{
			if(uri == IGNORE){
				Log.log(Log.DEBUG,Resolver.class,"ignored!");
			}else if(uri == null){
				Log.log(Log.DEBUG,Resolver.class,"not found "+id+" in cache");
			}else{
				Log.log(Log.DEBUG,Resolver.class,"found "+id+" in cache: "+uri);
			}
		}
		return uri;
	}
	
	// TODO: remove package access (for XMLPlugin)
	String resolvePublicOrSystem(String id,boolean isPublic) throws IOException
	{
		String uri = resolvePublicOrSystemFromCache(id, isPublic);
		if(uri == null)
			if(isPublic){
				return catalog.resolvePublic(id,null);
			}else{
				return catalog.resolveSystem(id);
			}
		else if(uri == IGNORE)
			return null;
		else{
			return uri;
		}
	} //}}}

	//{{{ copyToLocalFile() method
	private static File copyToLocalFile(Object session, VFS vfs, String path)
		throws IOException
	{
		if(jEdit.getSettingsDirectory() == null)
			return null;

		File _resourceDir = new File(resourceDir);
		if (!_resourceDir.exists())
			_resourceDir.mkdir();

		// Need to put this "copy from one stream to another"
		// into a common method some day, since other parts
		// of jEdit need it too...
		BufferedInputStream in = new BufferedInputStream(
			vfs._createInputStream(session,path,false,null));

		File localFile = File.createTempFile("cache", ".xml", _resourceDir);

		BufferedOutputStream out = new BufferedOutputStream(
			new FileOutputStream(localFile));

		byte[] buf = new byte[4096];
		int count = 0;
		while ((count = in.read(buf)) != -1)
			out.write(buf,0,count);
		out.close();

		return localFile;
	} //}}}

	private boolean showDownloadResourceDialog(Component comp, String systemId)
	{
		Entry e = new Entry(Entry.SYSTEM,systemId,null);
		if(resourceCache.get(e) == IGNORE)
			return false;

		int result = GUIUtilities.confirm(comp,"xml.download-resource",
			new String[] { systemId },JOptionPane.YES_NO_OPTION,
			JOptionPane.QUESTION_MESSAGE);
		if(result == JOptionPane.YES_OPTION)
			return true;
		else
		{
			resourceCache.put(e,IGNORE);
			return false;
		}
	} //}}}

	//{{{ addUserResource() method
	/**
	 * Don't want this public because then invoking {@link clearCache()}
	 * will remove this file, not what you would expect!
	 */
	private void addUserResource(String publicId, String systemId, String url)
	{
		if(DEBUG_RESOLVER)Log.log(Log.DEBUG,Resolver.class,"addUserResource("+publicId+","+systemId+","+url+")");
		if(publicId != null)
		{
			Entry pe = new Entry( Entry.PUBLIC, publicId, url );
			resourceCache.put( pe, url );
		}

		Entry se = new Entry( Entry.SYSTEM, systemId, url );
		resourceCache.put( se, url );
	} //}}}

	public static class Entry
	{
		public static final int SYSTEM = 0;
		public static final int PUBLIC = 1;

		public int type;
		public String id;
		public String uri;

		public Entry(int type, String id, String uri)
		{
			this.type = type;
			this.id = id;
			this.uri = uri;
		}

		public boolean equals(Object o)
		{
			if(o instanceof Entry)
			{
				Entry e = (Entry)o;
				return e.type == type && e.id.equals(id);
			}
			else
				return false;
		}

		public int hashCode()
		{
			return id.hashCode();
		}
		public String toString(){
			return "Resolver.Entry{"
				+(type==SYSTEM?"SYSTEM":"PUBLIC")
				+",id="+id
				+",uri="+uri
				+"}";
		}
	} //}}}
	//{{{ VFSUpdateHandler class
	/**
	 * Reloads all catalog files when the user changes one of it on disk.
	 * copied from CatalogManager
	 */
	public class VFSUpdateHandler implements EBComponent
	{
		public void handleMessage(EBMessage msg)
		{
			if(!loadedCatalogs)
				return;

			if(msg instanceof VFSUpdate)
			{
				String path = ((VFSUpdate)msg).getPath();
				if(catalogFiles.contains(path))
					loadedCatalogs = false;
			}
		}
	} //}}}

	//{{{ propertiesChanged() method
	public void propertiesChanged()
	{
		// reload the list of catalogs, in case the user added some in the
		// option pane
		loadedCatalogs = false;
	} //}}}


	static public boolean isUsingCache() {
		if(jEdit.getSettingsDirectory() == null) return false;
		return jEdit.getBooleanProperty(CACHE);
	}

	static public void setUsingCache(boolean newCache) {
		jEdit.setBooleanProperty(CACHE, newCache);
	}

	/**
	 *
	 * @return the network mode: LOCAL, ASK, or ALWAYS
	 */
	static public String getNetworkMode() {
		return jEdit.getProperty(MODE);

	}

	static public void setNetworkMode(String newMode) {
		if(!LOCAL.equals(newMode) && !ASK.equals(newMode) && !ALWAYS.equals(newMode))
			newMode = ASK;
		jEdit.setProperty(MODE, newMode);
	}
	
	public InputSource getExternalSubset(String name, String baseURI) throws SAXException, IOException
	{
		// TODO Auto-generated method stub
		return null;
	}

}