// ========================================================================
   // Copyright (c) 2004-2009 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.http;
  
  import java.io.IOException;
  
  import org.eclipse.jetty.io.Buffer;
  import org.eclipse.jetty.io.Buffers;
  import org.eclipse.jetty.io.ByteArrayBuffer;
  import org.eclipse.jetty.io.EndPoint;
  import org.eclipse.jetty.io.EofException;
  import org.eclipse.jetty.io.View;
  import org.eclipse.jetty.util.log.Log;
  import org.eclipse.jetty.util.log.Logger;
  
  /* ------------------------------------------------------------ */
  /**
   * Abstract Generator. Builds HTTP Messages.
   * 
   * Currently this class uses a system parameter "jetty.direct.writers" to control
   * two optional writer to byte conversions. buffer.writers=true will probably be 
   * faster, but will consume more memory.   This option is just for testing and tuning.
   * 
   */
  public abstract class AbstractGenerator implements Generator
  {
      private static final Logger LOG = Log.getLogger(AbstractGenerator.class);
  
      // states
      public final static int STATE_HEADER = 0;
      public final static int STATE_CONTENT = 2;
      public final static int STATE_FLUSHING = 3;
      public final static int STATE_END = 4;
      
      public static final byte[] NO_BYTES = {};
  
      // data
  
      protected final Buffers _buffers; // source of buffers
      protected final EndPoint _endp;
      
      protected int _state = STATE_HEADER;
      
      protected int _status = 0;
      protected int _version = HttpVersions.HTTP_1_1_ORDINAL;
      protected  Buffer _reason;
      protected  Buffer _method;
      protected  String _uri;
  
      protected long _contentWritten = 0;
      protected long _contentLength = HttpTokens.UNKNOWN_CONTENT;
      protected boolean _last = false;
      protected boolean _head = false;
      protected boolean _noContent = false;
      protected Boolean _persistent = null;
      
      protected Buffer _header; // Buffer for HTTP header (and maybe small _content)
      protected Buffer _buffer; // Buffer for copy of passed _content
      protected Buffer _content; // Buffer passed to addContent
      
      protected Buffer _date;
      
      private boolean _sendServerVersion;
  
      
      /* ------------------------------------------------------------------------------- */
      /**
       * Constructor.
       * 
       * @param buffers buffer pool
       * @param io the end point
       */
      public AbstractGenerator(Buffers buffers, EndPoint io)
      {
          this._buffers = buffers;
          this._endp = io;
      }
  
      /* ------------------------------------------------------------------------------- */
      public abstract boolean isRequest();
      
      /* ------------------------------------------------------------------------------- */
      public abstract boolean isResponse();
      
      /* ------------------------------------------------------------------------------- */
      public boolean isOpen()
      {
          return _endp.isOpen();
     }
     
     /* ------------------------------------------------------------------------------- */
     public void reset(boolean returnBuffers)
     {
         _state = STATE_HEADER;
         _status = 0;
         _version = HttpVersions.HTTP_1_1_ORDINAL;
         _reason = null;
         _last = false;
         _head = false;
         _noContent=false;
         _persistent = null;
         _contentWritten = 0;
         _contentLength = HttpTokens.UNKNOWN_CONTENT;
         _date = null;
 
         // always return the body buffer
         if (_buffer!=null)
             _buffers.returnBuffer(_buffer);
         _buffer=null;
 
         if (returnBuffers)
         {
             if (_header!=null)
                 _buffers.returnBuffer(_header);
             _header=null;
         }
         else if (_header != null) 
             _header.clear();
 
         _content = null;
         _method=null;
     }
 
     /* ------------------------------------------------------------------------------- */
     public void returnBuffers()
     {     
         if (_buffer!=null && _buffer.length()==0)
         {
             _buffers.returnBuffer(_buffer);
             _buffer=null;
         }
 
         if (_header!=null && _header.length()==0)
         {
             _buffers.returnBuffer(_header);
             _header=null;
         }         
     }
     
     /* ------------------------------------------------------------------------------- */
     public void resetBuffer()
     {                   
         if(_state>=STATE_FLUSHING)
             throw new IllegalStateException("Flushed");
         
         _last = false;
         _persistent=null;
         _contentWritten = 0;
         _contentLength = HttpTokens.UNKNOWN_CONTENT;
         _content=null;
         if (_buffer!=null)
             _buffer.clear();  
     }
 
     /* ------------------------------------------------------------ */
     /**
      * @return Returns the contentBufferSize.
      */
     public int getContentBufferSize()
     {
         if (_buffer==null)
             _buffer=_buffers.getBuffer();
         return _buffer.capacity();
     }
 
     /* ------------------------------------------------------------ */
     /**
      * @param contentBufferSize The contentBufferSize to set.
      */
     public void increaseContentBufferSize(int contentBufferSize)
     {
         if (_buffer==null)
             _buffer=_buffers.getBuffer();
         if (contentBufferSize > _buffer.capacity())
         {
             Buffer nb = _buffers.getBuffer(contentBufferSize);
             nb.put(_buffer);
             _buffers.returnBuffer(_buffer);
             _buffer = nb;
         }
     }
     
     /* ------------------------------------------------------------ */    
     public Buffer getUncheckedBuffer()
     {
         return _buffer;
     }
     
     /* ------------------------------------------------------------ */    
     public boolean getSendServerVersion ()
     {
         return _sendServerVersion;
     }
     
     /* ------------------------------------------------------------ */    
     public void setSendServerVersion (boolean sendServerVersion)
     {
         _sendServerVersion = sendServerVersion;
     }
     
     /* ------------------------------------------------------------ */
     public int getState()
     {
         return _state;
     }
 
     /* ------------------------------------------------------------ */
     public boolean isState(int state)
     {
         return _state == state;
     }
 
     /* ------------------------------------------------------------ */
     public boolean isComplete()
     {
         return _state == STATE_END;
     }
 
     /* ------------------------------------------------------------ */
     public boolean isIdle()
     {
         return _state == STATE_HEADER && _method==null && _status==0;
     }
 
     /* ------------------------------------------------------------ */
     public boolean isCommitted()
     {
         return _state != STATE_HEADER;
     }
 
     /* ------------------------------------------------------------ */
     /**
      * @return Returns the head.
      */
     public boolean isHead()
     {
         return _head;
     }
 
     /* ------------------------------------------------------------ */
     public void setContentLength(long value)
     {
         if (value<0)
             _contentLength=HttpTokens.UNKNOWN_CONTENT;
         else
             _contentLength=value;
     }
     
     /* ------------------------------------------------------------ */
     /**
      * @param head The head to set.
      */
     public void setHead(boolean head)
     {
         _head = head;
     }
 
     /* ------------------------------------------------------------ */
     /**
      * @return <code>false</code> if the connection should be closed after a request has been read,
      * <code>true</code> if it should be used for additional requests.
      */
     public boolean isPersistent()
     {
         return _persistent!=null
         ?_persistent.booleanValue()
         :(isRequest()?true:_version>HttpVersions.HTTP_1_0_ORDINAL);
     }
     
     /* ------------------------------------------------------------ */
     public void setPersistent(boolean persistent)
     {
         _persistent=persistent;
     }
 
     /* ------------------------------------------------------------ */
     /**
      * @param version The version of the client the response is being sent to (NB. Not the version
      *            in the response, which is the version of the server).
      */
     public void setVersion(int version)
     {
         if (_state != STATE_HEADER) 
             throw new IllegalStateException("STATE!=START "+_state);
         _version = version;
         if (_version==HttpVersions.HTTP_0_9_ORDINAL && _method!=null)
             _noContent=true;
     }
 
     /* ------------------------------------------------------------ */
     public int getVersion()
     {
         return _version;
     }
     
     /* ------------------------------------------------------------ */
     /**
      * @see org.eclipse.jetty.http.Generator#setDate(org.eclipse.jetty.io.Buffer)
      */
     public void setDate(Buffer timeStampBuffer)
     {
         _date=timeStampBuffer;
     }
 
     /* ------------------------------------------------------------ */
     /**
      */
     public void setRequest(String method, String uri)
     {
         if (method==null || HttpMethods.GET.equals(method) )
             _method=HttpMethods.GET_BUFFER;
         else
             _method=HttpMethods.CACHE.lookup(method);
         _uri=uri;
         if (_version==HttpVersions.HTTP_0_9_ORDINAL)
             _noContent=true;
     }
 
     /* ------------------------------------------------------------ */
     /**
      * @param status The status code to send.
      * @param reason the status message to send.
      */
     public void setResponse(int status, String reason)
     {
         if (_state != STATE_HEADER) throw new IllegalStateException("STATE!=START");
         _method=null;
         _status = status;
         if (reason!=null)
         {
             int len=reason.length();
             
             // TODO don't hard code
             if (len>1024)
                 len=1024;
             _reason=new ByteArrayBuffer(len);
             for (int i=0;i<len;i++)
             {
                 char ch = reason.charAt(i);
                 if (ch!='\r'&&ch!='\n')
                     _reason.put((byte)ch);
                 else
                     _reason.put((byte)' ');
             }
         }
     }
 
     /* ------------------------------------------------------------ */
     /** Prepare buffer for unchecked writes.
      * Prepare the generator buffer to receive unchecked writes
      * @return the available space in the buffer.
      * @throws IOException
      */
     public abstract int prepareUncheckedAddContent() throws IOException;
 
     /* ------------------------------------------------------------ */
     void uncheckedAddContent(int b)
     {
         _buffer.put((byte)b);
     }
 
     /* ------------------------------------------------------------ */
     public void completeUncheckedAddContent()
     {
         if (_noContent)
         {
             if(_buffer!=null)
                 _buffer.clear();
         }
         else 
         {
             _contentWritten+=_buffer.length();
             if (_head)
                 _buffer.clear();
         }
     }
     
     /* ------------------------------------------------------------ */
     public boolean isBufferFull()
     {
         if (_buffer != null && _buffer.space()==0)
         {
             if (_buffer.length()==0 && !_buffer.isImmutable())
                 _buffer.compact();
             return _buffer.space()==0;
         }
 
         return _content!=null && _content.length()>0;
     }
 
     /* ------------------------------------------------------------ */
     public boolean isWritten()
     {
         return _contentWritten>0;
     }
     
     /* ------------------------------------------------------------ */
     public boolean isAllContentWritten()
     {
         return _contentLength>=0 && _contentWritten>=_contentLength;
     }
     
     /* ------------------------------------------------------------ */
     public abstract void completeHeader(HttpFields fields, boolean allContentAdded) throws IOException;
     
     /* ------------------------------------------------------------ */
     /**
      * Complete the message.
      * 
      * @throws IOException
      */
     public void complete() throws IOException
     {
         if (_state == STATE_HEADER)
         {
             throw new IllegalStateException("State==HEADER");
         }
 
         if (_contentLength >= 0 && _contentLength != _contentWritten && !_head)
         {
             if (LOG.isDebugEnabled())
                 LOG.debug("ContentLength written=="+_contentWritten+" != contentLength=="+_contentLength);
             _persistent = false;
         }
     }
 
     /* ------------------------------------------------------------ */
     public abstract long flushBuffer() throws IOException;
 
     
     /* ------------------------------------------------------------ */
     public void flush(long maxIdleTime) throws IOException
     {
         // block until everything is flushed
         long now=System.currentTimeMillis();
         long end=now+maxIdleTime;
         Buffer content = _content;
         Buffer buffer = _buffer;
         if (content!=null && content.length()>0 || buffer!=null && buffer.length()>0 || isBufferFull())
         {
             flushBuffer();
             
             while (now<end && (content!=null && content.length()>0 ||buffer!=null && buffer.length()>0) && _endp.isOpen()&& !_endp.isOutputShutdown())
             {
                 blockForOutput(end-now);
                 now=System.currentTimeMillis();
             }
         }
         
         // make sure buffered data is also flushed
         while (now<end && _endp.isBufferingOutput() && _endp.isOpen() && !_endp.isOutputShutdown())
         {
             if (!_endp.isBlocking())
                 _endp.blockWritable(end-now);
             _endp.flush();
             now=System.currentTimeMillis();
         }
     }
 
     /* ------------------------------------------------------------ */
     /**
      * Utility method to send an error response. If the builder is not committed, this call is
      * equivalent to a setResponse, addContent and complete call.
      * 
      * @param code The error code
      * @param reason The error reason
      * @param content Contents of the error page
      * @param close True if the connection should be closed
      * @throws IOException if there is a problem flushing the response
      */
     public void sendError(int code, String reason, String content, boolean close) throws IOException
     {
         if (close)
             _persistent=false;
         if (isCommitted())
         {
             LOG.debug("sendError on committed: {} {}",code,reason);
         }
         else
         {
             LOG.debug("sendError: {} {}",code,reason);
             setResponse(code, reason);
             if (content != null) 
             {
                 completeHeader(null, false);
                 addContent(new View(new ByteArrayBuffer(content)), Generator.LAST);
             }
             else
             {
                 completeHeader(null, true);
             }
             complete();
         }
     }
 
     /* ------------------------------------------------------------ */
     /**
      * @return Returns the contentWritten.
      */
     public long getContentWritten()
     {
         return _contentWritten;
     }
     
 
 
     /* ------------------------------------------------------------ */
     public void  blockForOutput(long maxIdleTime) throws IOException
     {
         if (_endp.isBlocking())
         {
             try
             {
                 flushBuffer();
             }
             catch(IOException e)
             {
                 _endp.close();
                 throw e;
             }
         }
         else
         {
             if (!_endp.blockWritable(maxIdleTime))
             {
                 _endp.close();
                 throw new EofException("timeout");
             }
             
             flushBuffer();
         }
     }
     
 }