responsestream.java

来自「RESIN 3.2 最新源码」· Java 代码 · 共 811 行 · 第 1/2 页

/*
 * Copyright (c) 1998-2008 Caucho Technology -- all rights reserved
 *
 * This file is part of Resin(R) Open Source
 *
 * Each copy or derived work must preserve the copyright notice and this
 * notice unmodified.
 *
 * Resin Open Source is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * Resin Open Source is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, or any warranty
 * of NON-INFRINGEMENT.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Resin Open Source; if not, write to the
 *
 *   Free Software Foundation, Inc.
 *   59 Temple Place, Suite 330
 *   Boston, MA 02111-1307  USA
 *
 * @author Scott Ferguson
 */

package com.caucho.server.connection;

import com.caucho.log.Log;
import com.caucho.server.webapp.WebApp;
import com.caucho.util.L10N;
import com.caucho.vfs.ClientDisconnectException;
import com.caucho.vfs.WriteStream;

import javax.servlet.ServletContext;
import java.io.IOException;
import java.io.OutputStream;
import java.util.*;
import java.util.logging.Level;
import java.util.logging.Logger;

class ResponseStream extends ToByteResponseStream {
  static final Logger log = Logger.getLogger(ResponseStream.class.getName());
  
  static final L10N L = new L10N(ResponseStream.class);

  private static final int _tailChunkedLength = 7;
  private static final byte []_tailChunked =
    new byte[] {'\r', '\n', '0', '\r', '\n', '\r', '\n'};
  
  private final AbstractHttpResponse _response;
  
  private WriteStream _next;
  
  private OutputStream _cacheStream;
  private long _cacheMaxLength;
  // used for the direct copy and caching
  private int _bufferStartOffset;
  
  private boolean _chunkedEncoding;
  
  private int _bufferSize;
  private boolean _disableAutoFlush;
  
  // bytes actually written
  private int _contentLength;
  // True for the first chunk
  private boolean _isFirst;
  private boolean _isDisconnected;
  private boolean _isCommitted;

  private boolean _allowFlush = true;
  private boolean _isHead = false;
  private boolean _isClosed = false;
  
  private final byte []_buffer = new byte[16];

  ResponseStream(AbstractHttpResponse response)
  {
    _response = response;
  }

  public void init(WriteStream next)
  {
    _next = next;
  }
  
  /**
   * initializes the Response stream at the beginning of a request.
   */
  public void start()
  {
    super.start();
    
    _chunkedEncoding = false;

    _contentLength = 0;
    _allowFlush = true;
    _disableAutoFlush = false;
    _isClosed = false;
    _isHead = false;
    _cacheStream = null;
    _isDisconnected = false;
    _isCommitted = false;
    _isFirst = true;
    _bufferStartOffset = 0;
  }

  /**
   * Returns true for a Caucho response stream.
   */
  public boolean isCauchoResponseStream()
  {
    return true;
  }

  /**
   * Sets the underlying cache stream for a cached request.
   *
   * @param cache the cache stream.
   */
  public void setByteCacheStream(OutputStream cacheStream)
  {
    _cacheStream = cacheStream;
    
    CauchoRequest req = _response.getRequest();
    WebApp app = req.getWebApp();
    _cacheMaxLength = app.getCacheMaxLength();
  }

  /**
   * Response stream is a writable stream.
   */
  public boolean canWrite()
  {
    return true;
  }

  void setFlush(boolean flush)
  {
    _allowFlush = flush;
  }

  public void setAutoFlush(boolean isAutoFlush)
  {
    setDisableAutoFlush(! isAutoFlush);
  }

  void setDisableAutoFlush(boolean disable)
  {
    _disableAutoFlush = disable;
  }

  public void setHead()
  {
    _isHead = true;
    _bufferSize = 0;
  }

  public final boolean isHead()
  {
    return _isHead;
  }

  public int getContentLength()
  {
    return _contentLength;
  }

  public void setBufferSize(int size)
  {
    if (isCommitted())
      throw new IllegalStateException(L.l("Buffer size cannot be set after commit"));

    super.setBufferSize(size);
  }

  public boolean isCommitted()
  {
    // jsp/17ec
    return _isCommitted || _isClosed;
  }

  public void clear()
    throws IOException
  {
    clearBuffer();
    
    if (_isCommitted)
      throw new IOException(L.l("can't clear response after writing headers"));
  }
  
  public void clearBuffer()
  {
    super.clearBuffer();

    if (! _isCommitted) {
      // jsp/15la
      _isFirst = true;
      _bufferStartOffset = 0;
      _response.setHeaderWritten(false);
    }

    _next.setBufferOffset(_bufferStartOffset);
  }

  /**
   * Clear the closed state, because of the NOT_MODIFIED
   */
  public void clearClosed()
  {
    _isClosed = false;
  }

  private void writeHeaders(int length)
    throws IOException
  {
    _chunkedEncoding = _response.writeHeaders(_next, length);
  }

  /**
   * Returns the byte buffer.
   */
  public byte []getBuffer()
    throws IOException
  {
    flushBuffer();

    return _next.getBuffer();
  }

  /**
   * Returns the byte offset.
   */
  public int getBufferOffset()
    throws IOException
  {
    byte []buffer;
    int offset;

    flushBuffer();

    offset = _next.getBufferOffset();

    if (! _chunkedEncoding) {
      _bufferStartOffset = offset;
      return offset;
    }
    else if (_bufferStartOffset > 0) {
      return offset;
    }

    // chunked allocates 8 bytes for the chunk header
    buffer = _next.getBuffer();
    if (buffer.length - offset < 8) {
      _isCommitted = true;
      _next.flushBuffer();
      
      buffer = _next.getBuffer();
      offset = _next.getBufferOffset();
    }

    _bufferStartOffset = offset + 8;
    _next.setBufferOffset(offset + 8);

    return _bufferStartOffset;
  }

  /**
   * Sets the next buffer
   */
  public byte []nextBuffer(int offset)
    throws IOException
  {
    if (_isClosed)
      return _next.getBuffer();
    
    _isCommitted = true;
    
    int startOffset = _bufferStartOffset;
    _bufferStartOffset = 0;

    int length = offset - startOffset;
    long lengthHeader = _response.getContentLengthHeader();

    if (lengthHeader > 0 && lengthHeader < _contentLength + length) {
      lengthException(_next.getBuffer(), startOffset, length, lengthHeader);

      length = (int) (lengthHeader - _contentLength);
      offset = startOffset + length;
    }

    _contentLength += length;

    try {
      if (_isHead) {
	return _next.getBuffer();
      }
      else if (_chunkedEncoding) {
	if (length == 0)
	  throw new IllegalStateException();
      
	byte []buffer = _next.getBuffer();

	writeChunk(buffer, startOffset, length);

	buffer = _next.nextBuffer(offset);
	      
	if (log.isLoggable(Level.FINE))
	  log.fine(dbgId() + "write-chunk(" + offset + ")");

	_bufferStartOffset = 8 + _next.getBufferOffset();
	_next.setBufferOffset(_bufferStartOffset);

	return buffer;
      }
      else {
	if (_cacheStream != null)
	  writeCache(_next.getBuffer(), startOffset, length);
	
	byte []buffer = _next.nextBuffer(offset);
	      
	if (log.isLoggable(Level.FINE))
	  log.fine(dbgId() + "write-chunk(" + offset + ")");

	return buffer;
      }
    } catch (ClientDisconnectException e) {
      _response.killCache();

      if (_response.isIgnoreClientDisconnect()) {
        _isDisconnected = true;
	return _next.getBuffer();
      }
      else
        throw e;
    } catch (IOException e) {
      _response.killCache();
      
      throw e;
    }
  }

  /**
   * Sets the byte offset.
   */
  public void setBufferOffset(int offset)
    throws IOException
  {
    if (_isClosed)
      return;
    
    int startOffset = _bufferStartOffset;
    if (offset == startOffset)
      return;
    
    int length = offset - startOffset;
    long lengthHeader = _response.getContentLengthHeader();

    if (lengthHeader > 0 && lengthHeader < _contentLength + length) {
      lengthException(_next.getBuffer(), startOffset, length, lengthHeader);

      length = (int) (lengthHeader - _contentLength);
      offset = startOffset + length;
    }

    _contentLength += length;
    
    if (_cacheStream != null && ! _chunkedEncoding) {
      _bufferStartOffset = offset;
      writeCache(_next.getBuffer(), startOffset, length);
    }

    if (log.isLoggable(Level.FINE))
      log.fine(dbgId() +  "write-chunk(" + length + ")");

    if (! _isHead) {
      _next.setBufferOffset(offset);
    }
  }

  /**
   * Writes the next chunk of data to the response stream.
   *
   * @param buf the buffer containing the data
   * @param offset start offset into the buffer
   * @param length length of the data in the buffer
   */
  protected void writeNext(byte []buf, int offset, int length,
			   boolean isFinished)
    throws IOException
  {
    try {
      if (_isClosed)
	return;

      if (_disableAutoFlush && ! isFinished)
	throw new IOException(L.l("auto-flushing has been disabled"));
      
      boolean isFirst = _isFirst;
      _isFirst = false;

      if (! isFirst) {