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//
// ========================================================================
// Copyright (c) 1995-2014 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.http2.hpack;
import java.nio.ByteBuffer;
import org.eclipse.jetty.http.BadMessageException;
import org.eclipse.jetty.http.HostPortHttpField;
import org.eclipse.jetty.http.HttpField;
import org.eclipse.jetty.http.HttpHeader;
import org.eclipse.jetty.http.HttpMethod;
import org.eclipse.jetty.http.HttpScheme;
import org.eclipse.jetty.http.MetaData;
import org.eclipse.jetty.http2.hpack.HpackContext.Entry;
import org.eclipse.jetty.util.TypeUtil;
import org.eclipse.jetty.util.log.Log;
import org.eclipse.jetty.util.log.Logger;
/* ------------------------------------------------------------ */
/**
* This is not thread safe. May only be called by 1 thread at a time
*/
public class HpackDecoder
{
public static final Logger LOG = Log.getLogger(HpackDecoder.class);
private final HpackContext _context;
private final MetaDataBuilder _builder = new MetaDataBuilder();
private int _localMaxHeaderTableSize;
public HpackDecoder()
{
this(4096);
}
public HpackDecoder(int localMaxHeaderTableSize)
{
_context=new HpackContext(localMaxHeaderTableSize);
_localMaxHeaderTableSize=localMaxHeaderTableSize;
}
public void setLocalMaxHeaderTableSize(int localMaxHeaderTableSize)
{
_localMaxHeaderTableSize=localMaxHeaderTableSize;
}
public MetaData decode(ByteBuffer buffer)
{
if (LOG.isDebugEnabled())
LOG.debug(String.format("CtxTbl[%x] decoding",_context.hashCode()));
while(buffer.hasRemaining())
{
if (LOG.isDebugEnabled())
{
int l=Math.min(buffer.remaining(),16);
LOG.debug("decode "+TypeUtil.toHexString(buffer.array(),buffer.arrayOffset()+buffer.position(),l)+(l<buffer.remaining()?"...":""));
}
byte b = buffer.get();
if (b<0)
{
// indexed
int index = NBitInteger.decode(buffer,7);
Entry entry=_context.get(index);
if (entry.isInReferenceSet())
_context.get(index).removeFromRefSet();
else if (entry.isStatic())
{
LOG.debug("decode IdxStatic {}",entry);
// emit field
_builder.emit(entry.getHttpField());
// copy and add to reference set if there is room
Entry new_entry = _context.add(entry.getHttpField());
if (new_entry!=null)
_context.addToRefSet(new_entry);
}
else
{
LOG.debug("decode Idx {}",entry);
// emit
_builder.emit(entry.getHttpField());
// add to reference set
_context.addToRefSet(entry);
}
}
else
{
// look at the first nibble in detail
int f=(b&0xF0)>>4;
String name;
HttpHeader header;
String value;
if (f<=1 || f>=4)
{
// literal
boolean indexed=f>=4;
int bits=indexed?6:4;
boolean huffmanName=false;
// decode the name
int name_index=NBitInteger.decode(buffer,bits);
if (name_index>0)
{
Entry name_entry=_context.get(name_index);
name=name_entry.getHttpField().getName();
header=name_entry.getHttpField().getHeader();
}
else
{
huffmanName = (buffer.get()&0x80)==0x80;
int length = NBitInteger.decode(buffer,7);
if (huffmanName)
name=Huffman.decode(buffer,length);
else
name=toASCIIString(buffer,length);
for (int i=0;i<name.length();i++)
{
char c=name.charAt(i);
if (c>='A'&&c<='Z')
{
throw new BadMessageException(400,"Uppercase header name");
}
}
header=HttpHeader.CACHE.get(name);
}
// decode the value
boolean huffmanValue = (buffer.get()&0x80)==0x80;
int length = NBitInteger.decode(buffer,7);
if (huffmanValue)
value=Huffman.decode(buffer,length);
else
value=toASCIIString(buffer,length);
// Make the new field
HttpField field;
switch(name)
{
case ":method":
HttpMethod method=HttpMethod.CACHE.get(value);
if (method!=null)
field = new StaticValueHttpField(header,name,method.asString(),method);
else
field = new AuthorityHttpField(value);
break;
case ":status":
Integer code = Integer.valueOf(value);
field = new StaticValueHttpField(header,name,value,code);
break;
case ":scheme":
HttpScheme scheme=HttpScheme.CACHE.get(value);
if (scheme!=null)
field = new StaticValueHttpField(header,name,scheme.asString(),scheme);
else
field = new AuthorityHttpField(value);
break;
case ":authority":
field = new AuthorityHttpField(value);
break;
default:
field = new HttpField(header,name,value);
break;
}
if (LOG.isDebugEnabled())
LOG.debug("decoded '"+field+"' by Lit"+(name_index>0?"IdxName":(huffmanName?"HuffName":"LitName"))+(huffmanValue?"HuffVal":"LitVal")+(indexed?"Idx":""));
// emit the field
_builder.emit(field);
// if indexed
if (indexed)
{
// add to header table
Entry new_entry=_context.add(field);
// and to ref set if there was room in header table
if (new_entry!=null)
_context.addToRefSet(new_entry);
}
}
else if (f==2)
{
// change table size
int size = NBitInteger.decode(buffer,4);
if (LOG.isDebugEnabled())
LOG.debug("decode resize="+size);
if (size>_localMaxHeaderTableSize)
throw new IllegalArgumentException();
_context.resize(size);
}
else if (f==3)
{
// clear reference set
LOG.debug("decode clear");
_context.clearReferenceSet();
}
}
}
_context.emitUnusedReferences(_builder);
return _builder.build();
}
public static String toASCIIString(ByteBuffer buffer,int length)
{
StringBuilder builder = new StringBuilder(length);
int start=buffer.arrayOffset()+buffer.position();
int end=start+length;
buffer.position(end);
byte[] array=buffer.array();
for (int i=start;i<end;i++)
builder.append((char)(0x7f&array[i]));
return builder.toString();
}
}
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