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//
// ========================================================================
// Copyright (c) 1995 Mort Bay Consulting Pty Ltd and others.
//
// This program and the accompanying materials are made available under the
// terms of the Eclipse Public License v. 2.0 which is available at
// https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
// which is available at https://www.apache.org/licenses/LICENSE-2.0.
//
// SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
// ========================================================================
//
package org.eclipse.jetty.server.handler.gzip;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.channels.WritePendingException;
import java.util.concurrent.atomic.AtomicReference;
import java.util.zip.CRC32;
import java.util.zip.Deflater;
import org.eclipse.jetty.http.HttpField;
import org.eclipse.jetty.http.HttpFields;
import org.eclipse.jetty.http.HttpHeader;
import org.eclipse.jetty.http.HttpStatus;
import org.eclipse.jetty.io.RetainableByteBuffer;
import org.eclipse.jetty.server.Request;
import org.eclipse.jetty.server.Response;
import org.eclipse.jetty.util.BufferUtil;
import org.eclipse.jetty.util.Callback;
import org.eclipse.jetty.util.IteratingNestedCallback;
import org.eclipse.jetty.util.compression.DeflaterPool;
import org.eclipse.jetty.util.thread.Invocable;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import static org.eclipse.jetty.http.CompressedContentFormat.GZIP;
public class GzipResponseAndCallback extends Response.Wrapper implements Callback, Invocable
{
private static final Logger LOG = LoggerFactory.getLogger(GzipResponseAndCallback.class);
// Per RFC-1952 this is the "unknown" OS value byte.
private static final byte OS_UNKNOWN = (byte)0xFF;
private static final byte[] GZIP_HEADER = new byte[]{
(byte)0x1f, (byte)0x8b, Deflater.DEFLATED, 0, 0, 0, 0, 0, 0, OS_UNKNOWN
};
// Per RFC-1952, the GZIP trailer is 8 bytes
private static final int GZIP_TRAILER_SIZE = 8;
private enum GZState
{
// first state, indicating that content might be compressed, pending the state of the response
MIGHT_COMPRESS,
// the response is not being compressed (this is a final state)
NOT_COMPRESSING,
// The response is being committed (no changes to compress state can be made at this point)
COMMITTING,
// The response is compressing its body content
COMPRESSING,
// The last content has is being compressed and deflater is being flushed
FINISHING,
// The content has finished compressing and trailers have been sent (this is a final state)
FINISHED
}
private final AtomicReference _state = new AtomicReference<>(GZState.MIGHT_COMPRESS);
private final CRC32 _crc = new CRC32();
private final Callback _callback;
private final GzipFactory _factory;
private final int _bufferSize;
private final boolean _syncFlush;
private DeflaterPool.Entry _deflaterEntry;
private RetainableByteBuffer _buffer;
private boolean _last;
public GzipResponseAndCallback(GzipHandler handler, Request request, Response response, Callback callback)
{
super(request, response);
_callback = callback;
_factory = handler;
_bufferSize = Math.max(GZIP_HEADER.length + GZIP_TRAILER_SIZE, request.getConnectionMetaData().getHttpConfiguration().getOutputBufferSize());
_syncFlush = handler.isSyncFlush();
}
@Override
public void succeeded()
{
try
{
// We need to write nothing here to intercept the committing of the
// response and possibly change headers in case write is never called.
if (_last)
_callback.succeeded();
else
write(true, null, _callback);
}
finally
{
if (getRequest() instanceof GzipRequest gzipRequest)
gzipRequest.destroy();
}
}
@Override
public void failed(Throwable x)
{
try
{
_callback.failed(x);
}
finally
{
if (getRequest() instanceof GzipRequest gzipRequest)
gzipRequest.destroy();
}
}
@Override
public InvocationType getInvocationType()
{
return _callback.getInvocationType();
}
@Override
public void write(boolean last, ByteBuffer content, Callback callback)
{
_last = last;
switch (_state.get())
{
case MIGHT_COMPRESS -> commit(last, callback, content);
case NOT_COMPRESSING -> super.write(last, content, callback);
case COMMITTING -> callback.failed(new WritePendingException());
case COMPRESSING -> gzip(last, callback, content);
default ->
{
if (BufferUtil.isEmpty(content))
callback.succeeded();
else
callback.failed(new IllegalStateException("state=" + _state.get()));
}
}
}
private void addTrailer(ByteBuffer outputBuffer)
{
if (LOG.isDebugEnabled())
LOG.debug("addTrailer: _crc={}, _totalIn={})", _crc.getValue(), _deflaterEntry.get().getTotalIn());
outputBuffer.putInt((int)_crc.getValue());
outputBuffer.putInt(_deflaterEntry.get().getTotalIn());
}
private void gzip(boolean complete, final Callback callback, ByteBuffer content)
{
if (content != null || complete)
new GzipBufferCB(complete, callback, content).iterate();
else
callback.succeeded();
}
protected void commit(boolean last, Callback callback, ByteBuffer content)
{
if (LOG.isDebugEnabled())
LOG.debug("commit(last={}, callback={}, content={})", last, callback, BufferUtil.toDetailString(content));
Request request = getRequest();
Response response = this;
HttpFields.Mutable fields = response.getHeaders();
// Are we excluding because of status?
int sc = response.getStatus();
if (sc > 0 && (sc < 200 || sc == 204 || sc == 205 || sc >= 300))
{
if (LOG.isDebugEnabled())
LOG.debug("{} exclude by status {}", this, sc);
noCompression();
if (sc == HttpStatus.NOT_MODIFIED_304)
{
String requestEtags = (String)request.getAttribute(GzipHandler.GZIP_HANDLER_ETAGS);
String responseEtag = fields.get(HttpHeader.ETAG);
if (requestEtags != null && responseEtag != null)
{
String responseEtagGzip = etagGzip(responseEtag);
if (requestEtags.contains(responseEtagGzip))
fields.put(HttpHeader.ETAG, responseEtagGzip);
}
}
super.write(last, content, callback);
return;
}
// Are we excluding because of mime-type?
String ct = fields.get(HttpHeader.CONTENT_TYPE);
if (ct != null)
{
String baseType = HttpField.getValueParameters(ct, null);
if (!_factory.isMimeTypeDeflatable(baseType))
{
if (LOG.isDebugEnabled())
LOG.debug("{} exclude by mimeType {}", this, ct);
noCompression();
super.write(last, content, callback);
return;
}
}
// Has the Content-Encoding header already been set?
String ce = fields.get(HttpHeader.CONTENT_ENCODING);
if (ce != null)
{
if (LOG.isDebugEnabled())
LOG.debug("{} exclude by content-encoding {}", this, ce);
noCompression();
super.write(last, content, callback);
return;
}
// If there is nothing to write, don't compress.
if (last && BufferUtil.isEmpty(content))
{
if (LOG.isDebugEnabled())
LOG.debug("{} exclude by nothing to write", this);
noCompression();
super.write(true, content, callback);
return;
}
// Are we the thread that commits?
if (_state.compareAndSet(GZState.MIGHT_COMPRESS, GZState.COMMITTING))
{
long contentLength = fields.getLongField(HttpHeader.CONTENT_LENGTH);
if (contentLength < 0 && last)
contentLength = BufferUtil.length(content);
_deflaterEntry = _factory.getDeflaterEntry(request, contentLength);
if (_deflaterEntry == null)
{
if (LOG.isDebugEnabled())
LOG.debug("{} exclude no deflater", this);
_state.set(GZState.NOT_COMPRESSING);
super.write(last, content, callback);
return;
}
fields.put(GZIP.getContentEncoding());
_crc.reset();
// Adjust headers
fields.remove(HttpHeader.CONTENT_LENGTH);
String etag = fields.get(HttpHeader.ETAG);
if (etag != null)
fields.put(HttpHeader.ETAG, etagGzip(etag));
if (LOG.isDebugEnabled())
LOG.debug("{} compressing {}", this, _deflaterEntry);
_state.set(GZState.COMPRESSING);
if (BufferUtil.isEmpty(content))
{
// We are committing, but have no content to compress, so flush empty buffer to write headers.
super.write(last, content, callback);
}
else
{
gzip(last, callback, content);
}
}
else
{
callback.failed(new WritePendingException());
}
}
private String etagGzip(String etag)
{
return GZIP.etag(etag);
}
public void noCompression()
{
while (true)
{
switch (_state.get())
{
case NOT_COMPRESSING:
return;
case MIGHT_COMPRESS:
if (_state.compareAndSet(GZState.MIGHT_COMPRESS, GZState.NOT_COMPRESSING))
return;
break;
default:
throw new IllegalStateException(_state.get().toString());
}
}
}
private class GzipBufferCB extends IteratingNestedCallback
{
private final ByteBuffer _content;
private final boolean _last;
public GzipBufferCB(boolean complete, Callback callback, ByteBuffer content)
{
super(callback);
_content = content;
_last = complete;
if (_content != null)
{
_crc.update(_content.slice());
Deflater deflater = _deflaterEntry.get();
deflater.setInput(_content);
}
if (LOG.isDebugEnabled())
LOG.debug("GzipBufferCB(complete={}, callback={}, content={})", complete, callback, BufferUtil.toDetailString(content));
}
@Override
protected Action process() throws Exception
{
if (LOG.isDebugEnabled())
LOG.debug("GzipBufferCB.process(): _last={}, _buffer={}, _content={}", _last, _buffer, BufferUtil.toDetailString(_content));
GZState gzstate = _state.get();
// Are we finished?
if (gzstate == GZState.FINISHED)
{
// then the trailer has been generated and written below.
// We have finished compressing the entire content, so
// cleanup and succeed.
cleanup();
return Action.SUCCEEDED;
}
// If we have no buffer
if (_buffer == null)
{
_buffer = getRequest().getComponents().getByteBufferPool().acquire(_bufferSize, false);
ByteBuffer byteBuffer = _buffer.getByteBuffer();
// Per RFC-1952, GZIP is LITTLE_ENDIAN
byteBuffer.order(ByteOrder.LITTLE_ENDIAN);
BufferUtil.flipToFill(byteBuffer);
// Add GZIP Header
byteBuffer.put(GZIP_HEADER, 0, GZIP_HEADER.length);
}
else
{
// otherwise clear the buffer as previous writes will always fully consume.
BufferUtil.clearToFill(_buffer.getByteBuffer());
}
Deflater deflater = _deflaterEntry.get();
return switch (gzstate)
{
case COMPRESSING -> compressing(deflater, _buffer.getByteBuffer());
case FINISHING -> finishing(deflater, _buffer.getByteBuffer());
default -> throw new IllegalStateException("Unexpected state [" + _state.get() + "]");
};
}
@Override
protected void onCompleteFailure(Throwable x)
{
cleanup();
super.onCompleteFailure(x);
}
private void cleanup()
{
if (_deflaterEntry != null)
{
_state.set(GZState.FINISHED);
_deflaterEntry.release();
_deflaterEntry = null;
}
if (_buffer != null)
{
_buffer.release();
_buffer = null;
}
}
private int getFlushMode()
{
return _syncFlush ? Deflater.SYNC_FLUSH : Deflater.NO_FLUSH;
}
/**
* This method is called directly from {@link #process()} to perform the compressing of
* the content this {@link GzipBufferCB} represents.
*/
private Action compressing(Deflater deflater, ByteBuffer outputBuffer)
{
if (LOG.isDebugEnabled())
LOG.debug("compressing() deflater={}, outputBuffer={}", deflater, BufferUtil.toDetailString(outputBuffer));
if (!deflater.finished())
{
if (!deflater.needsInput())
{
int len = deflater.deflate(outputBuffer, getFlushMode());
if (len > 0)
{
BufferUtil.flipToFlush(outputBuffer, 0);
write(false, outputBuffer);
return Action.SCHEDULED;
}
}
}
if (_last)
{
_state.set(GZState.FINISHING);
deflater.finish();
return finishing(deflater, outputBuffer);
}
BufferUtil.flipToFlush(outputBuffer, 0);
if (outputBuffer.hasRemaining())
{
write(false, outputBuffer);
return Action.SCHEDULED;
}
// the content held by GzipBufferCB is fully consumed as input to the Deflater instance, we are done
if (BufferUtil.isEmpty(_content))
return Action.SUCCEEDED;
// No progress made on deflate, but the _content wasn't consumed, we shouldn't be able to reach this.
throw new AssertionError("No progress on deflate made for " + this);
}
/**
* This method is called by {@link #compressing(Deflater, ByteBuffer)}, once the last chunk is compressed;
* or directly from {@link #process()} if an earlier call to this method was unable to complete.
*/
private Action finishing(Deflater deflater, ByteBuffer outputBuffer)
{
if (LOG.isDebugEnabled())
LOG.debug("finishing() deflater={}, outputBuffer={}", deflater, BufferUtil.toDetailString(outputBuffer));
if (!deflater.finished())
{
int len = deflater.deflate(outputBuffer, getFlushMode());
// try to preserve single write if possible (header + compressed content + trailer)
if (deflater.finished() && outputBuffer.remaining() >= GZIP_TRAILER_SIZE)
{
_state.set(GZState.FINISHED);
addTrailer(outputBuffer);
BufferUtil.flipToFlush(outputBuffer, 0);
write(true, outputBuffer);
return Action.SCHEDULED;
}
if (len > 0)
{
BufferUtil.flipToFlush(outputBuffer, 0);
write(false, outputBuffer);
return Action.SCHEDULED;
}
// No progress made on deflate, deflater not finished, we shouldn't be able to reach this.
throw new AssertionError("No progress on deflate made for " + this);
}
else
{
_state.set(GZState.FINISHED);
addTrailer(outputBuffer);
BufferUtil.flipToFlush(outputBuffer, 0);
write(true, outputBuffer);
return Action.SCHEDULED;
}
}
private void write(boolean last, ByteBuffer outputBuffer)
{
if (LOG.isDebugEnabled())
LOG.debug("write() last={}, outputBuffer={}", last, BufferUtil.toDetailString(outputBuffer));
GzipResponseAndCallback.super.write(last, outputBuffer, this);
}
@Override
public String toString()
{
return String.format("%s[content=%s last=%b buffer=%s deflate=%s %s]",
super.toString(),
BufferUtil.toDetailString(_content),
_last,
_buffer,
_deflaterEntry,
_state.get());
}
}
}