// ========================================================================
   // Copyright (c) 1999-2009 Mort Bay Consulting Pty. Ltd.
   // ------------------------------------------------------------------------
   // All rights reserved. This program and the accompanying materials
   // are made available under the terms of the Eclipse Public License v1.0
   // and Apache License v2.0 which accompanies this distribution.
   // The Eclipse Public License is available at 
   // http://www.eclipse.org/legal/epl-v10.html
   // The Apache License v2.0 is available at
  // http://www.opensource.org/licenses/apache2.0.php
  // You may elect to redistribute this code under either of these licenses. 
  // ========================================================================
  
  package org.eclipse.jetty.servlet;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.net.MalformedURLException;
  import java.net.URL;
  import java.util.Enumeration;
  import java.util.List;
  
  import javax.servlet.RequestDispatcher;
  import javax.servlet.ServletContext;
  import javax.servlet.ServletException;
  import javax.servlet.UnavailableException;
  import javax.servlet.http.HttpServlet;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  
  import org.eclipse.jetty.http.HttpContent;
  import org.eclipse.jetty.http.HttpFields;
  import org.eclipse.jetty.http.HttpHeaderValues;
  import org.eclipse.jetty.http.HttpHeaders;
  import org.eclipse.jetty.http.HttpMethods;
  import org.eclipse.jetty.http.MimeTypes;
  import org.eclipse.jetty.io.Buffer;
  import org.eclipse.jetty.io.ByteArrayBuffer;
  import org.eclipse.jetty.io.WriterOutputStream;
  import org.eclipse.jetty.server.Connector;
  import org.eclipse.jetty.server.Dispatcher;
  import org.eclipse.jetty.server.HttpConnection;
  import org.eclipse.jetty.server.InclusiveByteRange;
  import org.eclipse.jetty.server.ResourceCache;
  import org.eclipse.jetty.server.Response;
  import org.eclipse.jetty.server.handler.ContextHandler;
  import org.eclipse.jetty.server.nio.NIOConnector;
  import org.eclipse.jetty.util.IO;
  import org.eclipse.jetty.util.MultiPartOutputStream;
  import org.eclipse.jetty.util.TypeUtil;
  import org.eclipse.jetty.util.URIUtil;
  import org.eclipse.jetty.util.log.Log;
  import org.eclipse.jetty.util.resource.FileResource;
  import org.eclipse.jetty.util.resource.Resource;
  import org.eclipse.jetty.util.resource.ResourceFactory;
  
  
  
  /* ------------------------------------------------------------ */
  /** The default servlet.                                                 
   * This servlet, normally mapped to /, provides the handling for static 
   * content, OPTION and TRACE methods for the context.                   
   * The following initParameters are supported, these can be set either
   * on the servlet itself or as ServletContext initParameters with a prefix
   * of org.eclipse.jetty.servlet.Default. :                          
   * <PRE>                                                                      
   *   acceptRanges     If true, range requests and responses are         
   *                    supported                                         
   *                                                                      
   *   dirAllowed       If true, directory listings are returned if no    
   *                    welcome file is found. Else 403 Forbidden.        
   *
   *   welcomeServlets  If true, attempt to dispatch to welcome files
   *                    that are servlets, but only after no matching static
   *                    resources could be found.
   *                   
   *                    This must be false if you want directory listings,
   *                    but have index.jsp in your welcome file list.
   *
   *   redirectWelcome  If true, welcome files are redirected rather than
   *                    forwarded to.
   *
   *   gzip             If set to true, then static content will be served as 
   *                    gzip content encoded if a matching resource is 
   *                    found ending with ".gz"
   *
   *  resourceBase      Set to replace the context resource base
   *
   *  relativeResourceBase    
   *                    Set with a pathname relative to the base of the
   *                    servlet context root. Useful for only serving static content out
   *                    of only specific subdirectories.
   * 
   *  aliases           If True, aliases of resources are allowed (eg. symbolic
   *                    links and caps variations). May bypass security constraints.
   *                    
   *  maxCacheSize      The maximum total size of the cache or 0 for no cache.
   *  maxCachedFileSize The maximum size of a file to cache
  *  maxCachedFiles    The maximum number of files to cache
  *  cacheType         Set to "bio", "nio" or "both" to determine the type resource cache. 
  *                    A bio cached buffer may be used by nio but is not as efficient as an
  *                    nio buffer.  An nio cached buffer may not be used by bio.    
  *  
  *  useFileMappedBuffer 
  *                    If set to true, it will use mapped file buffer to serve static content
  *                    when using NIO connector. Setting this value to false means that
  *                    a direct buffer will be used instead of a mapped file buffer. 
  *                    By default, this is set to true.
  *                    
  *  cacheControl      If set, all static content will have this value set as the cache-control
  *                    header.
  *                    
  * 
  * </PRE>
  *                                                                    
  *
  * 
  * 
  */
 public class DefaultServlet extends HttpServlet implements ResourceFactory
 {   
     private ServletContext _servletContext;
     private ContextHandler _contextHandler;
     
     private boolean _acceptRanges=true;
     private boolean _dirAllowed=true;
     private boolean _welcomeServlets=false;
     private boolean _redirectWelcome=false;
     private boolean _gzip=true;
     
     private Resource _resourceBase;
     private NIOResourceCache _nioCache;
     private ResourceCache _bioCache;
     
     private MimeTypes _mimeTypes;
     private String[] _welcomes;
     private boolean _useFileMappedBuffer=false;
     private ByteArrayBuffer _cacheControl;
     private String _relativeResourceBase;
     
     
     /* ------------------------------------------------------------ */
     @Override
     public void init()
         throws UnavailableException
     {
         _servletContext=getServletContext();
         ContextHandler.Context scontext=ContextHandler.getCurrentContext();
         if (scontext==null)
             _contextHandler=((ContextHandler.Context)_servletContext).getContextHandler();
         else
             _contextHandler = ContextHandler.getCurrentContext().getContextHandler();
         
         _mimeTypes = _contextHandler.getMimeTypes();
         
         _welcomes = _contextHandler.getWelcomeFiles();
         if (_welcomes==null)
             _welcomes=new String[] {"index.jsp","index.html"};
         
         _acceptRanges=getInitBoolean("acceptRanges",_acceptRanges);
         _dirAllowed=getInitBoolean("dirAllowed",_dirAllowed);
         _welcomeServlets=getInitBoolean("welcomeServlets", _welcomeServlets);
         _redirectWelcome=getInitBoolean("redirectWelcome",_redirectWelcome);
         _gzip=getInitBoolean("gzip",_gzip);
         
         if (getInitParameter("aliases")!=null)
             _contextHandler.setAliases(getInitBoolean("aliases",false));
         
         boolean aliases=_contextHandler.isAliases();
         if (!aliases && !FileResource.getCheckAliases())
             throw new IllegalStateException("Alias checking disabled");
         if (aliases)
             _servletContext.log("Aliases are enabled");
         
         _useFileMappedBuffer=getInitBoolean("useFileMappedBuffer",_useFileMappedBuffer);
         
         _relativeResourceBase = getInitParameter("relativeResourceBase");
         
         String rb=getInitParameter("resourceBase");
         if (rb!=null)
         {
             if (_relativeResourceBase!=null)
                 throw new  UnavailableException("resourceBase & relativeResourceBase");    
             try{_resourceBase=_contextHandler.newResource(rb);}
             catch (Exception e) 
             {
                 Log.warn(Log.EXCEPTION,e);
                 throw new UnavailableException(e.toString()); 
             }
         }
         
         String t=getInitParameter("cacheControl");
         if (t!=null)
             _cacheControl=new ByteArrayBuffer(t);
         
         try
         {
             String cache_type =getInitParameter("cacheType");
             int max_cache_size=getInitInt("maxCacheSize", -2);
             int max_cached_file_size=getInitInt("maxCachedFileSize", -2);
             int max_cached_files=getInitInt("maxCachedFiles", -2);
 
             if (cache_type==null || "nio".equals(cache_type)|| "both".equals(cache_type))
             {
                 if (max_cache_size==-2 || max_cache_size>0)
                 {
                     _nioCache=new NIOResourceCache(_mimeTypes);
                     _nioCache.setUseFileMappedBuffer(_useFileMappedBuffer);
                     if (max_cache_size>0)
                         _nioCache.setMaxCacheSize(max_cache_size);    
                     if (max_cached_file_size>=-1)
                         _nioCache.setMaxCachedFileSize(max_cached_file_size);    
                     if (max_cached_files>=-1)
                         _nioCache.setMaxCachedFiles(max_cached_files);
                     _nioCache.start();
                 }
             }
             if ("bio".equals(cache_type)|| "both".equals(cache_type))
             {
                 if (max_cache_size==-2 || max_cache_size>0)
                 {
                     _bioCache=new ResourceCache(_mimeTypes);
                     if (max_cache_size>0)
                         _bioCache.setMaxCacheSize(max_cache_size);    
                     if (max_cached_file_size>=-1)
                         _bioCache.setMaxCachedFileSize(max_cached_file_size);    
                     if (max_cached_files>=-1)
                         _bioCache.setMaxCachedFiles(max_cached_files);
                     _bioCache.start();
                 }
             }
             if (_nioCache==null)
                 _bioCache=null;
            
         }
         catch (Exception e) 
         {
             Log.warn(Log.EXCEPTION,e);
             throw new UnavailableException(e.toString()); 
         }
         
         if (Log.isDebugEnabled()) Log.debug("resource base = "+_resourceBase);
     }
 
     /* ------------------------------------------------------------ */
     @Override
     public String getInitParameter(String name)
     {
         String value=getServletContext().getInitParameter("org.eclipse.jetty.servlet.Default."+name);
 	if (value==null)
 	    value=super.getInitParameter(name);
 	return value;
     }
     
     /* ------------------------------------------------------------ */
     private boolean getInitBoolean(String name, boolean dft)
     {
         String value=getInitParameter(name);
         if (value==null || value.length()==0)
             return dft;
         return (value.startsWith("t")||
                 value.startsWith("T")||
                 value.startsWith("y")||
                 value.startsWith("Y")||
                 value.startsWith("1"));
     }
     
     /* ------------------------------------------------------------ */
     private int getInitInt(String name, int dft)
     {
         String value=getInitParameter(name);
 	if (value==null)
             value=getInitParameter(name);
         if (value!=null && value.length()>0)
             return Integer.parseInt(value);
         return dft;
     }
     
     /* ------------------------------------------------------------ */
     /** get Resource to serve.
      * Map a path to a resource. The default implementation calls
      * HttpContext.getResource but derived servlets may provide
      * their own mapping.
      * @param pathInContext The path to find a resource for.
      * @return The resource to serve.
      */
     public Resource getResource(String pathInContext)
     {
         Resource r=null;
         if (_relativeResourceBase!=null)
             pathInContext=URIUtil.addPaths(_relativeResourceBase,pathInContext);
         
         try
         {
             if (_resourceBase!=null)
                 r = _resourceBase.addPath(pathInContext);
             else
             {
                 URL u = _servletContext.getResource(pathInContext);
                 r = _contextHandler.newResource(u);
             }
            
             if (Log.isDebugEnabled()) Log.debug("RESOURCE="+r);
         }
         catch (IOException e)
         {
             Log.ignore(e);
         }
         return r;
     }
     
     /* ------------------------------------------------------------ */
     @Override
     protected void doGet(HttpServletRequest request, HttpServletResponse response)
     	throws ServletException, IOException
     {
         String servletPath=null;
         String pathInfo=null;
         Enumeration reqRanges = null;
         boolean byteRangeRules = false;
         Boolean included =request.getAttribute(Dispatcher.INCLUDE_REQUEST_URI)!=null;
         if (included!=null && included.booleanValue())
         {
             servletPath=(String)request.getAttribute(Dispatcher.INCLUDE_SERVLET_PATH);
             pathInfo=(String)request.getAttribute(Dispatcher.INCLUDE_PATH_INFO);
             if (servletPath==null)
             {
                 servletPath=request.getServletPath();
                 pathInfo=request.getPathInfo();
             }
         }
         else
         {
             included = Boolean.FALSE;
             servletPath = request.getServletPath();
             pathInfo = request.getPathInfo();
 
             // Is this a Content-Range request?
             reqRanges = request.getHeaders(HttpHeaders.CONTENT_RANGE);
             if (!hasDefinedRange(reqRanges))
             {
                 // Is this a Range request?
                 reqRanges = request.getHeaders(HttpHeaders.RANGE);
                 if (hasDefinedRange(reqRanges))
                 {
                     byteRangeRules = true;
                 }
                 else
                 {
                     reqRanges = null;
                 }
             }
         }
         
         String pathInContext=URIUtil.addPaths(servletPath,pathInfo);
         boolean endsWithSlash=pathInContext.endsWith(URIUtil.SLASH);
         
         // Can we gzip this request?
         String pathInContextGz=null;
         boolean gzip=false;
         if (!included.booleanValue() && _gzip && reqRanges==null && !endsWithSlash )
         {
             String accept=request.getHeader(HttpHeaders.ACCEPT_ENCODING);
             if (accept!=null && accept.indexOf("gzip")>=0)
                 gzip=true;
         }
         
         // Find the resource and content
         Resource resource=null;
         HttpContent content=null;
         
         Connector connector = HttpConnection.getCurrentConnection().getConnector();
         ResourceCache cache=(connector instanceof NIOConnector) ?_nioCache:_bioCache;
         try
         {   
             // Try gzipped content first
             if (gzip)
             {
                 pathInContextGz=pathInContext+".gz";  
 
                 if (cache==null)
                 {
                     resource=getResource(pathInContextGz);
                 }
                 else
                 {
                     content=cache.lookup(pathInContextGz,this);
 
                     if (content!=null)
                         resource=content.getResource();
                     else
                         resource=getResource(pathInContextGz);
                 }
 
                 if (resource==null || !resource.exists()|| resource.isDirectory())
                 {
                     if (cache!=null && content==null)
                     {
                         String real_path=_servletContext.getRealPath(pathInContextGz);
                         if (real_path!=null)
                             cache.miss(pathInContextGz,_contextHandler.newResource(real_path));
                     }
                     gzip=false;
                     pathInContextGz=null;
                 }
             }
         
             // find resource
             if (!gzip)
             {
                 if (cache==null)
                     resource=getResource(pathInContext);
                 else
                 {
                     content=cache.lookup(pathInContext,this);
 
                     if (content!=null)
                         resource=content.getResource();
                     else
                         resource=getResource(pathInContext);
                 }
             }
             
             if (Log.isDebugEnabled())
                 Log.debug("resource="+resource+(content!=null?" content":""));
                         
             // Handle resource
             if (resource==null || !resource.exists())
                 response.sendError(HttpServletResponse.SC_NOT_FOUND);
             else if (!resource.isDirectory())
             {   
                 if (endsWithSlash && _contextHandler.isAliases() && pathInContext.length()>1)
                 {
                     String q=request.getQueryString();
                     pathInContext=pathInContext.substring(0,pathInContext.length()-1);
                     if (q!=null&&q.length()!=0)
                         pathInContext+="?"+q;
                     response.sendRedirect(response.encodeRedirectURL(URIUtil.addPaths(_servletContext.getContextPath(),pathInContext)));
                 }
 		else
 		{
 		    // ensure we have content
 		    if (content==null)
 			content=new UnCachedContent(resource);
 		    
 		    if (included.booleanValue() || passConditionalHeaders(request,response, resource,content))  
 		    {
 			if (gzip)
 			{
 			   response.setHeader(HttpHeaders.CONTENT_ENCODING,"gzip");
 			   String mt=_servletContext.getMimeType(pathInContext);
 			   if (mt!=null)
 			       response.setContentType(mt);
 			}
 			sendData(request,response,included.booleanValue(),resource,content,reqRanges,byteRangeRules);  
 		    }
 		}
             }
             else
             {
                 String welcome=null;
                 
                 if (!endsWithSlash || (pathInContext.length()==1 && request.getAttribute("org.eclipse.jetty.server.nullPathInfo")!=null))
                 {
                     StringBuffer buf=request.getRequestURL();
                     synchronized(buf)
                     {
                         int param=buf.lastIndexOf(";");
                         if (param<0)
                             buf.append('/');
                         else
                             buf.insert(param,'/');
                         String q=request.getQueryString();
                         if (q!=null&&q.length()!=0)
                         {
                             buf.append('?');
                             buf.append(q);
                         }
                         response.setContentLength(0);
                         response.sendRedirect(response.encodeRedirectURL(buf.toString()));
                     }
                 }
                 // else look for a welcome file
                 else if (null!=(welcome=getWelcomeFile(resource)))
                 {
                     String ipath=URIUtil.addPaths(pathInContext,welcome);
                     if (_redirectWelcome)
                     {
                         // Redirect to the index
                         response.setContentLength(0);
                         String q=request.getQueryString();
                         if (q!=null&&q.length()!=0)
                             response.sendRedirect(response.encodeRedirectURL(URIUtil.addPaths( _servletContext.getContextPath(),ipath)+"?"+q));
                         else
                             response.sendRedirect(response.encodeRedirectURL(URIUtil.addPaths( _servletContext.getContextPath(),ipath)));
                     }
                     else
                     {
                         // Forward to the index
                         RequestDispatcher dispatcher=request.getRequestDispatcher(ipath);
                         if (dispatcher!=null)
                         {
                             if (included.booleanValue())
                                 dispatcher.include(request,response);
                             else
                             {
                                 request.setAttribute("org.eclipse.jetty.server.welcome",ipath);
                                 dispatcher.forward(request,response);
                             }
                         }
                     }
                 }
                 else 
                 {
                     content=new UnCachedContent(resource);
                     if (included.booleanValue() || passConditionalHeaders(request,response, resource,content))
                         sendDirectory(request,response,resource,pathInContext.length()>1);
                 }
             }
         }
         catch(IllegalArgumentException e)
         {
             Log.warn(Log.EXCEPTION,e);
             if(!response.isCommitted())
                 response.sendError(500, e.getMessage());
         }
         finally
         {
             if (content!=null)
                 content.release();
             else if (resource!=null)
                 resource.release();
         }
         
     }
     
     private boolean hasDefinedRange(Enumeration reqRanges)
     {
         return (reqRanges!=null && reqRanges.hasMoreElements());
     }
 
     /* ------------------------------------------------------------ */
     @Override
     protected void doPost(HttpServletRequest request, HttpServletResponse response)
         throws ServletException, IOException
     {
         doGet(request,response);
     }
     
     /* ------------------------------------------------------------ */
     /* (non-Javadoc)
      * @see javax.servlet.http.HttpServlet#doTrace(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)
      */
     @Override
     protected void doTrace(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException
     {
         resp.sendError(HttpServletResponse.SC_METHOD_NOT_ALLOWED);
     }
 
     /* ------------------------------------------------------------ */
     /**
      * Finds a matching welcome file for the supplied {@link Resource}. This will be the first entry in the list of 
      * configured {@link #_welcomes welcome files} that existing within the directory referenced by the <code>Resource</code>.
      * If the resource is not a directory, or no matching file is found, then it may look for a valid servlet mapping.
      * If there is none, then <code>null</code> is returned.
      * The list of welcome files is read from the {@link ContextHandler} for this servlet, or
      * <code>"index.jsp" , "index.html"</code> if that is <code>null</code>.
      * @param resource
      * @return The name of the matching welcome file.
      * @throws IOException
      * @throws MalformedURLException
      */
     private String getWelcomeFile(Resource resource) throws MalformedURLException, IOException
     {
         if (!resource.isDirectory() || _welcomes==null)
             return null;
 
         for (int i=0;i<_welcomes.length;i++)
         {
             Resource welcome=resource.addPath(_welcomes[i]);
             if (welcome.exists())
                 return _welcomes[i];
         }
 
         if (_welcomeServlets)
         {
 	        ServletHandler servletHandler = (ServletHandler)_contextHandler.getChildHandlerByClass(ServletHandler.class);
 	     	for (int i=0;i<_welcomes.length;i++)
 	     	{
 	     		if (servletHandler.matchesPath(_welcomes[i]))
 	     			return _welcomes[i];
 	     	}
         }
 
         return null;
     }
 
     /* ------------------------------------------------------------ */
     /* Check modification date headers.
      */
     protected boolean passConditionalHeaders(HttpServletRequest request,HttpServletResponse response, Resource resource, HttpContent content)
     throws IOException
     {
         try
         {
             if (!request.getMethod().equals(HttpMethods.HEAD) )
             {
                 String ifms=request.getHeader(HttpHeaders.IF_MODIFIED_SINCE);
                 if (ifms!=null)
                 {
                     if (content!=null)
                     {
                         Buffer mdlm=content.getLastModified();
                         if (mdlm!=null)
                         {
                             if (ifms.equals(mdlm.toString()))
                             {
                                 response.reset();
                                 response.setStatus(HttpServletResponse.SC_NOT_MODIFIED);
                                 response.flushBuffer();
                                 return false;
                             }
                         }
                     }
                         
                     long ifmsl=request.getDateHeader(HttpHeaders.IF_MODIFIED_SINCE);
                     if (ifmsl!=-1)
                     {
                         if (resource.lastModified()/1000 <= ifmsl/1000)
                         {
                             response.reset();
                             response.setStatus(HttpServletResponse.SC_NOT_MODIFIED);
                             response.flushBuffer();
                             return false;
                         }
                     }
                 }
 
                 // Parse the if[un]modified dates and compare to resource
                 long date=request.getDateHeader(HttpHeaders.IF_UNMODIFIED_SINCE);
                 
                 if (date!=-1)
                 {
                     if (resource.lastModified()/1000 > date/1000)
                     {
                         response.sendError(HttpServletResponse.SC_PRECONDITION_FAILED);
                         return false;
                     }
                 }
                 
             }
         }
         catch(IllegalArgumentException iae)
         {
             if(!response.isCommitted())
                 response.sendError(400, iae.getMessage());
             throw iae;
         }
         return true;
     }
     
     
     /* ------------------------------------------------------------------- */
     protected void sendDirectory(HttpServletRequest request,
                                  HttpServletResponse response,
                                  Resource resource,
                                  boolean parent)
     throws IOException
     {
         if (!_dirAllowed)
         {
             response.sendError(HttpServletResponse.SC_FORBIDDEN);
             return;
         }
         
         byte[] data=null;
         String base = URIUtil.addPaths(request.getRequestURI(),URIUtil.SLASH);
         String dir = resource.getListHTML(base,parent);
         if (dir==null)
         {
             response.sendError(HttpServletResponse.SC_FORBIDDEN,
             "No directory");
             return;
         }
         
         data=dir.getBytes("UTF-8");
         response.setContentType("text/html; charset=UTF-8");
         response.setContentLength(data.length);
         response.getOutputStream().write(data);
     }
     
     /* ------------------------------------------------------------ */
     protected void sendData(HttpServletRequest request,
                             HttpServletResponse response,
                             boolean include,
                             Resource resource,
                             HttpContent content,
                             Enumeration reqRanges,
                             boolean byteRangeRules)
     throws IOException
     {
         long content_length=resource.length();
         
         // Get the output stream (or writer)
         OutputStream out =null;
         try{out = response.getOutputStream();}
         catch(IllegalStateException e) {out = new WriterOutputStream(response.getWriter());}
         
         if ( reqRanges == null || !reqRanges.hasMoreElements())
         {
             //  if there were no ranges, send entire entity
             if (include)
             {
                 resource.writeTo(out,0,content_length);
             }
             else
             {
                 // See if a direct methods can be used?
                 if (out instanceof HttpConnection.Output)
                 {
                     if (response instanceof Response)
                     {
                         writeOptionHeaders(((Response)response).getHttpFields());
                         ((HttpConnection.Output)out).sendContent(content);
                     }
                     else if (content.getBuffer()!=null)
                     {
                         writeHeaders(response,content,content_length);
                         ((HttpConnection.Output)out).sendContent(content.getBuffer());
                     }
                     else
                     {
                         writeHeaders(response,content,content_length);
                         resource.writeTo(out,0,content_length);
                     }
                 }
                 else
                 {
                     // Write content normally
                     writeHeaders(response,content,content_length);
                     resource.writeTo(out,0,content_length);
                 }
             }
         }
         else
         {
             // Parse the satisfiable ranges
             List ranges =InclusiveByteRange.satisfiableRanges(reqRanges,byteRangeRules,content_length);
             
             //  if there are no satisfiable ranges, send 416 response
             if (ranges==null || ranges.size()==0)
             {
                 writeHeaders(response, content, content_length);
                 response.setStatus(HttpServletResponse.SC_REQUESTED_RANGE_NOT_SATISFIABLE);
                 response.setHeader(HttpHeaders.CONTENT_RANGE, 
                         InclusiveByteRange.to416HeaderRangeString(content_length));
                 resource.writeTo(out,0,content_length);
                 return;
             }
             
             //  if there is only a single valid range (must be satisfiable 
             //  since were here now), send that range with a 216 response
             if ( ranges.size()== 1)
             {
                 InclusiveByteRange singleSatisfiableRange =
                     (InclusiveByteRange)ranges.get(0);
                 long singleLength = singleSatisfiableRange.getSize(content_length);
                 writeHeaders(response,content,singleLength                     );
                 response.setStatus(HttpServletResponse.SC_PARTIAL_CONTENT);
                 response.setHeader(HttpHeaders.CONTENT_RANGE, 
                         singleSatisfiableRange.toHeaderRangeString(content_length));
                 resource.writeTo(out,singleSatisfiableRange.getFirst(content_length),singleLength);
                 return;
             }
             
             // If not following byte range rules (such as when using the "Content-Range" request)
             // There is no possibility of sending a multi-part range.
             // See http://tools.ietf.org/html/rfc2616#section-14.16
             if (!byteRangeRules)
             {
                 writeHeaders(response,content,content_length);
                 response.setStatus(HttpServletResponse.SC_REQUESTED_RANGE_NOT_SATISFIABLE);
                 response.setHeader(HttpHeaders.CONTENT_RANGE,InclusiveByteRange.to416HeaderRangeString(content_length));
                 resource.writeTo(out,0,content_length);
                 return;
             }
             
             //  multiple non-overlapping valid ranges cause a multipart
             //  216 response which does not require an overall 
             //  content-length header
             //
             writeHeaders(response,content,-1);
             String mimetype=content.getContentType().toString();
             MultiPartOutputStream multi = new MultiPartOutputStream(out);
             response.setStatus(HttpServletResponse.SC_PARTIAL_CONTENT);
             
             // If the request has a "Request-Range" header then we need to
             // send an old style multipart/x-byteranges Content-Type. This
             // keeps Netscape and acrobat happy. This is what Apache does.
             String ctp;
             if (request.getHeader(HttpHeaders.REQUEST_RANGE)!=null)
                 ctp = "multipart/x-byteranges; boundary=";
             else
                 ctp = "multipart/byteranges; boundary=";
             response.setContentType(ctp+multi.getBoundary());
             
             InputStream in=resource.getInputStream();
             long pos=0;
             
             for (int i=0;i<ranges.size();i++)
             {
                 InclusiveByteRange ibr = (InclusiveByteRange) ranges.get(i);
                 String header=HttpHeaders.CONTENT_RANGE+": "+
                 ibr.toHeaderRangeString(content_length);
                 multi.startPart(mimetype,new String[]{header});
                 
                 long start=ibr.getFirst(content_length);
                 long size=ibr.getSize(content_length);
                 if (in!=null)
                 {
                     // Handle non cached resource
                     if (start<pos)
                     {
                         in.close();
                         in=resource.getInputStream();
                         pos=0;
                     }
                     if (pos<start)
                     {
                         in.skip(start-pos);
                         pos=start;
                     }
                     IO.copy(in,multi,size);
                     pos+=size;
                 }
                 else
                     // Handle cached resource
                     (resource).writeTo(multi,start,size);
                 
             }
             if (in!=null)
                 in.close();
             multi.close();
         }
         return;
     }
     
     /* ------------------------------------------------------------ */
     protected void writeHeaders(HttpServletResponse response,HttpContent content,long count)
         throws IOException
     {   
         if (content.getContentType()!=null && response.getContentType()==null)
             response.setContentType(content.getContentType().toString());
         
         if (response instanceof Response)
         {
             Response r=(Response)response;
             HttpFields fields = r.getHttpFields();
 
             if (content.getLastModified()!=null)  
                 fields.put(HttpHeaders.LAST_MODIFIED_BUFFER,content.getLastModified(),content.getResource().lastModified());
             else if (content.getResource()!=null)
             {
                 long lml=content.getResource().lastModified();
                 if (lml!=-1)
                     fields.putDateField(HttpHeaders.LAST_MODIFIED_BUFFER,lml);
             }
                 
             if (count != -1)
                 r.setLongContentLength(count);
 
             writeOptionHeaders(fields);
         }
         else
         {
             long lml=content.getResource().lastModified();
             if (lml>=0)
                 response.setDateHeader(HttpHeaders.LAST_MODIFIED,lml);
 
             if (count != -1)
             {
                 if (count<Integer.MAX_VALUE)
                     response.setContentLength((int)count);
                 else 
                     response.setHeader(HttpHeaders.CONTENT_LENGTH,TypeUtil.toString(count));
             }
             
             writeOptionHeaders(response);
         }
     }
 
     /* ------------------------------------------------------------ */
     protected void writeOptionHeaders(HttpFields fields) throws IOException
     { 
         if (_acceptRanges)
             fields.put(HttpHeaders.ACCEPT_RANGES_BUFFER,HttpHeaderValues.BYTES_BUFFER);
 
         if (_cacheControl!=null)
             fields.put(HttpHeaders.CACHE_CONTROL_BUFFER,_cacheControl);
     }
     
     /* ------------------------------------------------------------ */
     protected void writeOptionHeaders(HttpServletResponse response) throws IOException
     { 
         if (_acceptRanges)
             response.setHeader(HttpHeaders.ACCEPT_RANGES,"bytes");
 
         if (_cacheControl!=null)
             response.setHeader(HttpHeaders.CACHE_CONTROL,_cacheControl.toString());
     }
 
     /* ------------------------------------------------------------ */
     /* 
      * @see javax.servlet.Servlet#destroy()
      */
     @Override
     public void destroy()
     {
         try
         {
             if (_nioCache!=null)
                 _nioCache.stop();
             if (_bioCache!=null)
                 _bioCache.stop();
         }
         catch(Exception e)
         {
             Log.warn(Log.EXCEPTION,e);
         }
         finally
         {
             super.destroy();
         }
     }
 
     /* ------------------------------------------------------------ */
     /* ------------------------------------------------------------ */
     /* ------------------------------------------------------------ */
     private class UnCachedContent implements HttpContent
     {
         Resource _resource;
         
         UnCachedContent(Resource resource)
         {
             _resource=resource;
         }
         
         /* ------------------------------------------------------------ */
         public Buffer getContentType()
         {
             return _mimeTypes.getMimeByExtension(_resource.toString());
         }
 
         /* ------------------------------------------------------------ */
         public Buffer getLastModified()
         {
             return null;
         }
 
         /* ------------------------------------------------------------ */
         public Buffer getBuffer()
         {
             return null;
         }
 
         /* ------------------------------------------------------------ */
         public long getContentLength()
         {
             return _resource.length();
         }
 
         /* ------------------------------------------------------------ */
         public InputStream getInputStream() throws IOException
         {
             return _resource.getInputStream();
         }
 
         /* ------------------------------------------------------------ */
         public Resource getResource()
         {
             return _resource;
         }
 
         /* ------------------------------------------------------------ */
         public void release()
         {
             _resource.release();
             _resource=null;
         }
         
     }
 }