jetty-http2/http2-hpack/src/main/java/org/eclipse/jetty/http2/hpack/MetaDataBuilder.java

//
//  ========================================================================
//  Copyright (c) 1995-2015 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 org.eclipse.jetty.http.BadMessageException;
import org.eclipse.jetty.http.HostPortHttpField;
import org.eclipse.jetty.http.HttpField;
import org.eclipse.jetty.http.HttpFields;
import org.eclipse.jetty.http.HttpScheme;
import org.eclipse.jetty.http.HttpStatus;
import org.eclipse.jetty.http.HttpVersion;
import org.eclipse.jetty.http.MetaData;

public class MetaDataBuilder
{ 
    private final int _maxSize;
    private int _size;
    private int _status;
    private String _method;
    private HttpScheme _scheme;
    private HostPortHttpField _authority;
    private String _path;  
    private long _contentLength=Long.MIN_VALUE;

    private HttpFields _fields = new HttpFields(10);
    
    /* ------------------------------------------------------------ */
    /**
     * @param maxHeadersSize The maximum size of the headers, expressed as total name and value characters.
     */
    MetaDataBuilder(int maxHeadersSize)
    {
        _maxSize=maxHeadersSize;
    }
    
    /** Get the maxSize.
     * @return the maxSize
     */
    public int getMaxSize()
    {
        return _maxSize;
    }

    /** Get the size.
     * @return the current size in bytes
     */
    public int getSize()
    {
        return _size;
    }

    public void emit(HttpField field)
    {        
        int field_size = field.getName().length()+field.getValue().length();
        _size+=field_size;
        if (_size>_maxSize)
            throw new BadMessageException(HttpStatus.REQUEST_ENTITY_TOO_LARGE_413,"Header size "+_size+">"+_maxSize);
        
        if (field instanceof StaticTableHttpField)
        {
            StaticTableHttpField value = (StaticTableHttpField)field;
            switch(field.getHeader())
            {
                case C_STATUS:
                    _status=(Integer)value.getStaticValue();
                    break;
                    
                case C_METHOD:
                    _method=field.getValue();
                    break;

                case C_SCHEME:
                    _scheme = (HttpScheme)value.getStaticValue();
                    break;
                    
                default:
                    throw new IllegalArgumentException(field.getName());
            }
        }
        else if (field.getHeader()!=null)
        {
            switch(field.getHeader())
            {
                case C_STATUS:
                    _status=field.getIntValue();
                    break;

                case C_METHOD:
                    _method=field.getValue();
                    break;

                case C_SCHEME:
                    _scheme = HttpScheme.CACHE.get(field.getValue());
                    break;

                case C_AUTHORITY:
                    _authority=(field instanceof HostPortHttpField)?((HostPortHttpField)field):new AuthorityHttpField(field.getValue());
                    break;

                case HOST:
                    // :authority fields must come first.  If we have one, ignore the host header as far as authority goes.
                    if (_authority==null)
                        _authority=(field instanceof HostPortHttpField)?((HostPortHttpField)field):new AuthorityHttpField(field.getValue());
                    _fields.add(field);
                    break;

                case C_PATH:
                    _path = field.getValue();
                    break;

                case CONTENT_LENGTH:
                    _contentLength = field.getLongValue();
                    _fields.add(field);
                    break;
                    
                default:
                    if (field.getName().charAt(0)!=':')
                        _fields.add(field);
            }
        }
        else
        {
            if (field.getName().charAt(0)!=':')
                _fields.add(field);
        }
    }
    
    public MetaData build()
    {
        try
        {
            HttpFields fields = _fields;
            _fields = new HttpFields(Math.max(10,fields.size()+5));
            
            if (_method!=null)
                return new MetaData.Request(_method,_scheme,_authority,_path,HttpVersion.HTTP_2,fields,_contentLength);
            if (_status!=0)
                return new MetaData.Response(HttpVersion.HTTP_2,_status,fields,_contentLength);
            return new MetaData(HttpVersion.HTTP_2,fields,_contentLength);
        }
        finally
        {
            _status=0;
            _method=null;
            _scheme=null;
            _authority=null;
            _path=null;
            _size=0;
            _contentLength=Long.MIN_VALUE;
        }
    }

    /* ------------------------------------------------------------ */
    /** Check that the max size will not be exceeded.
     * @param length the length
     * @param huffman the huffman name
     */
    public void checkSize(int length, boolean huffman)
    {
        // Apply a huffman fudge factor
        if (huffman)
            length=(length*4)/3;
        if ((_size+length)>_maxSize)
            throw new BadMessageException(HttpStatus.REQUEST_ENTITY_TOO_LARGE_413,"Header size "+(_size+length)+">"+_maxSize);
    }
}