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The core jetty server artifact.
//
// ========================================================================
// Copyright (c) 1995-2022 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.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.http.PreEncodedHttpField;
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.slf4j.Logger;
import org.slf4j.LoggerFactory;
import static org.eclipse.jetty.http.CompressedContentFormat.GZIP;
public class GzipResponse extends Response.Wrapper
{
public static Logger LOG = LoggerFactory.getLogger(GzipResponse.class);
private static final byte[] GZIP_HEADER = new byte[]{(byte)0x1f, (byte)0x8b, Deflater.DEFLATED, 0, 0, 0, 0, 0, 0, 0};
public static final HttpField VARY_ACCEPT_ENCODING = new PreEncodedHttpField(HttpHeader.VARY, HttpHeader.ACCEPT_ENCODING.asString());
private enum GZState
{
MIGHT_COMPRESS, NOT_COMPRESSING, COMMITTING, COMPRESSING, FINISHED
}
private final AtomicReference _state = new AtomicReference<>(GZState.MIGHT_COMPRESS);
private final CRC32 _crc = new CRC32();
private final GzipFactory _factory;
private final HttpField _vary;
private final int _bufferSize;
private final boolean _syncFlush;
private DeflaterPool.Entry _deflaterEntry;
private ByteBuffer _buffer;
public GzipResponse(Request request, Response wrapped, GzipFactory factory, HttpField vary, int bufferSize, boolean syncFlush)
{
super(request, wrapped);
_factory = factory;
_vary = vary;
_bufferSize = bufferSize;
_syncFlush = syncFlush;
}
@Override
public void write(boolean last, ByteBuffer content, Callback callback)
{
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 -> callback.failed(new IllegalStateException("state=" + _state.get()));
}
}
private void addTrailer()
{
BufferUtil.putIntLittleEndian(_buffer, (int)_crc.getValue());
BufferUtil.putIntLittleEndian(_buffer, _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)
{
// Are we excluding because of status?
Response response = GzipResponse.this;
Request request = response.getRequest();
int sc = response.getStatus();
if (sc > 0 && (sc < 200 || sc == 204 || sc == 205 || sc >= 300))
{
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 = response.getHeaders().get(HttpHeader.ETAG);
if (requestEtags != null && responseEtag != null)
{
String responseEtagGzip = etagGzip(responseEtag);
if (requestEtags.contains(responseEtagGzip))
response.getHeaders().put(HttpHeader.ETAG, responseEtagGzip);
}
}
super.write(last, content, callback);
return;
}
// Are we excluding because of mime-type?
String ct = response.getHeaders().get(HttpHeader.CONTENT_TYPE);
if (ct != null)
{
String baseType = HttpField.valueParameters(ct, null);
if (!_factory.isMimeTypeGzipable(baseType))
{
LOG.debug("{} exclude by mimeType {}", this, ct);
noCompression();
super.write(last, content, callback);
return;
}
}
// Has the Content-Encoding header already been set?
HttpFields.Mutable fields = response.getHeaders();
String ce = fields.get(HttpHeader.CONTENT_ENCODING);
if (ce != null)
{
LOG.debug("{} exclude by content-encoding {}", this, ce);
noCompression();
super.write(last, content, callback);
return;
}
// Are we the thread that commits?
if (_state.compareAndSet(GZState.MIGHT_COMPRESS, GZState.COMMITTING))
{
// We are varying the response due to accept encoding header.
if (_vary != null)
fields.ensureField(_vary);
long contentLength = response.getHeaders().getLongField(HttpHeader.CONTENT_LENGTH);
if (contentLength < 0 && last)
contentLength = BufferUtil.length(content);
_deflaterEntry = _factory.getDeflaterEntry(request, contentLength);
if (_deflaterEntry == null)
{
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
response.getHeaders().putLongField(HttpHeader.CONTENT_LENGTH, -1);
String etag = fields.get(HttpHeader.ETAG);
if (etag != null)
fields.put(HttpHeader.ETAG, etagGzip(etag));
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 ByteBuffer _copy;
private final ByteBuffer _content;
private final boolean _last;
public GzipBufferCB(boolean complete, Callback callback, ByteBuffer content)
{
super(callback);
_content = content;
_last = complete;
}
@Override
protected void onCompleteFailure(Throwable x)
{
if (_deflaterEntry != null)
{
_deflaterEntry.release();
_deflaterEntry = null;
}
super.onCompleteFailure(x);
}
@Override
protected Action process() throws Exception
{
// If we have no deflater
if (_deflaterEntry == null)
{
// then the trailer has been generated and written below.
// We have finished compressing the entire content, so
// cleanup and succeed.
if (_buffer != null)
{
getRequest().getComponents().getByteBufferPool().release(_buffer);
_buffer = null;
}
if (_copy != null)
{
getRequest().getComponents().getByteBufferPool().release(_copy);
_copy = null;
}
return Action.SUCCEEDED;
}
// If we have no buffer
if (_buffer == null)
{
// allocate a buffer and add the gzip header.
_buffer = getRequest().getComponents().getByteBufferPool().acquire(_bufferSize, false);
BufferUtil.fill(_buffer, GZIP_HEADER, 0, GZIP_HEADER.length);
}
else
{
// otherwise clear the buffer as previous writes will always fully consume.
BufferUtil.clear(_buffer);
}
// If the deflater is not finished, then compress more data.
Deflater deflater = _deflaterEntry.get();
if (!deflater.finished())
{
if (deflater.needsInput())
{
ByteBuffer content = _content != null ? _content : BufferUtil.EMPTY_BUFFER;
// If there is no more content available to compress,
// then we have either finished all content or just the current write.
if (BufferUtil.isEmpty(content))
{
if (_last)
{
deflater.finish();
}
else if (BufferUtil.isEmpty(_buffer))
{
return Action.SUCCEEDED;
}
else
{
GzipResponse.super.write(false, _buffer, this);
return Action.SCHEDULED;
}
}
else
{
// TODO: this part is wrong, as there is a ByteBuffer Deflater API
// and we don't want to copy direct ByteBuffers.
// The comment below about CRC32.update() is IMHO wrong, as
// in Jetty 10 we use it without problems.
// If there is more content available to compress, we have to make sure
// it is available in an array for the current deflater API, maybe slicing
// of content.
ByteBuffer slice;
if (content.hasArray())
{
slice = content;
}
else
{
if (_copy == null)
_copy = getRequest().getComponents().getByteBufferPool().acquire(_bufferSize, false);
else
BufferUtil.clear(_copy);
slice = _copy;
BufferUtil.append(_copy, content);
}
// transfer the data from the slice to the deflater
byte[] array = slice.array();
int off = slice.arrayOffset() + slice.position();
int len = slice.remaining();
_crc.update(array, off, len);
// Ideally we would want to use the ByteBuffer API for Deflaters. However due the the ByteBuffer implementation
// of the CRC32.update() it is less efficient for us to use this rather than to convert to array ourselves.
_deflaterEntry.get().setInput(array, off, len);
slice.position(slice.position() + len);
if (_last && _content == null && BufferUtil.isEmpty(content))
deflater.finish();
}
}
// deflate the content into the available space in the buffer
int off = _buffer.arrayOffset() + _buffer.limit();
int len = BufferUtil.space(_buffer);
int produced = deflater.deflate(_buffer.array(), off, len, _syncFlush ? Deflater.SYNC_FLUSH : Deflater.NO_FLUSH);
_buffer.limit(_buffer.limit() + produced);
}
// If we have finished deflation and there is room for the trailer.
if (deflater.finished() && BufferUtil.space(_buffer) >= 8)
{
// add the trailer and recycle the deflator to flag that we will have had completeSuccess when
// the write below completes.
addTrailer();
_deflaterEntry.release();
_deflaterEntry = null;
}
// write the compressed buffer.
GzipResponse.super.write(_deflaterEntry == null, _buffer, this);
return Action.SCHEDULED;
}
@Override
public String toString()
{
return String.format("%s[content=%s last=%b copy=%s buffer=%s deflate=%s %s]",
super.toString(),
BufferUtil.toDetailString(_content),
_last,
BufferUtil.toDetailString(_copy),
BufferUtil.toDetailString(_buffer),
_deflaterEntry,
_deflaterEntry != null && _deflaterEntry.get().finished() ? "(finished)" : "");
}
}
}