org.eclipse.jetty.websocket.api.util.QuoteUtil Maven / Gradle / Ivy
//
// ========================================================================
// Copyright (c) 1995-2013 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.websocket.api.util;
import java.io.IOException;
import java.util.Arrays;
import java.util.Iterator;
import java.util.NoSuchElementException;
/**
* Provide some consistent Http header value and Extension configuration parameter quoting support.
*
* While QuotedStringTokenizer exists in jetty-util, and works great with http header values, using it in websocket-api is undesired.
*
*
* - Using QuotedStringTokenizer would introduce a dependency to jetty-util that would need to be exposed via the WebAppContext classloader
* - ABNF defined extension parameter parsing requirements of RFC-6455 (WebSocket) ABNF, is slightly different than the ABNF parsing defined in RFC-2616
* (HTTP/1.1).
* - Future HTTPbis ABNF changes for parsing will impact QuotedStringTokenizer
*
* It was decided to keep this implementation separate for the above reasons.
*/
public class QuoteUtil
{
private static class DeQuotingStringIterator implements Iterator
{
private enum State
{
START,
TOKEN,
QUOTE_SINGLE,
QUOTE_DOUBLE
}
private static final boolean DEBUG = false;
private final String input;
private final String delims;
private StringBuilder token;
private boolean hasToken = false;
private int i = 0;
public DeQuotingStringIterator(String input, String delims)
{
this.input = input;
this.delims = delims;
int len = input.length();
token = new StringBuilder(len > 1024?512:len / 2);
}
private void appendToken(char c)
{
if (hasToken)
{
token.append(c);
}
else
{
if (Character.isWhitespace(c))
{
return; // skip whitespace at start of token.
}
else
{
token.append(c);
hasToken = true;
}
}
}
private void debug(String format, Object... args)
{
if (DEBUG)
{
System.out.printf(format,args);
}
}
@Override
public boolean hasNext()
{
// already found a token
if (hasToken)
{
return true;
}
State state = State.START;
boolean escape = false;
int inputLen = input.length();
while (i < inputLen)
{
char c = input.charAt(i++);
switch (state)
{
case START:
{
if (c == '\'')
{
state = State.QUOTE_SINGLE;
appendToken(c);
}
else if (c == '\"')
{
state = State.QUOTE_DOUBLE;
appendToken(c);
}
else
{
appendToken(c);
state = State.TOKEN;
}
break;
}
case TOKEN:
{
if (delims.indexOf(c) >= 0)
{
debug("hasNext/t: %b [%s]%n",hasToken,token);
return hasToken;
}
else if (c == '\'')
{
state = State.QUOTE_SINGLE;
}
else if (c == '\"')
{
state = State.QUOTE_DOUBLE;
}
appendToken(c);
break;
}
case QUOTE_SINGLE:
{
if (escape)
{
escape = false;
appendToken(c);
}
else if (c == '\'')
{
appendToken(c);
state = State.TOKEN;
}
else if (c == '\\')
{
escape = true;
}
else
{
appendToken(c);
}
break;
}
case QUOTE_DOUBLE:
{
if (escape)
{
escape = false;
appendToken(c);
}
else if (c == '\"')
{
appendToken(c);
state = State.TOKEN;
}
else if (c == '\\')
{
escape = true;
}
else
{
appendToken(c);
}
break;
}
}
debug("%s <%s> : [%s]%n",state,c,token);
}
debug("hasNext/e: %b [%s]%n",hasToken,token);
return hasToken;
}
@Override
public String next()
{
if (!hasNext())
{
throw new NoSuchElementException();
}
String ret = token.toString();
token.setLength(0);
hasToken = false;
return QuoteUtil.dequote(ret.trim());
}
@Override
public void remove()
{
throw new UnsupportedOperationException("Remove not supported with this iterator");
}
}
/**
* ABNF from RFC 2616, RFC 822, and RFC 6455 specified characters requiring quoting.
*/
public static final String ABNF_REQUIRED_QUOTING = "\"'\\\n\r\t\f\b%+ ;=";
private static final char UNICODE_TAG = 0xFFFF;
private static final char[] escapes = new char[32];
static
{
Arrays.fill(escapes,UNICODE_TAG);
// non-unicode
escapes['\b'] = 'b';
escapes['\t'] = 't';
escapes['\n'] = 'n';
escapes['\f'] = 'f';
escapes['\r'] = 'r';
}
private static int dehex(byte b)
{
if ((b >= '0') && (b <= '9'))
{
return (byte)(b - '0');
}
if ((b >= 'a') && (b <= 'f'))
{
return (byte)((b - 'a') + 10);
}
if ((b >= 'A') && (b <= 'F'))
{
return (byte)((b - 'A') + 10);
}
throw new IllegalArgumentException("!hex:" + Integer.toHexString(0xff & b));
}
/**
* Remove quotes from a string, only if the input string start with and end with the same quote character.
*
* @param str
* the string to remove surrounding quotes from
* @return the de-quoted string
*/
public static String dequote(String str)
{
char start = str.charAt(0);
if ((start == '\'') || (start == '\"'))
{
// possibly quoted
char end = str.charAt(str.length() - 1);
if (start == end)
{
// dequote
return str.substring(1,str.length() - 1);
}
}
return str;
}
public static void escape(StringBuilder buf, String str)
{
for (char c : str.toCharArray())
{
if (c >= 32)
{
// non special character
if ((c == '"') || (c == '\\'))
{
buf.append('\\');
}
buf.append(c);
}
else
{
// special characters, requiring escaping
char escaped = escapes[c];
// is this a unicode escape?
if (escaped == UNICODE_TAG)
{
buf.append("\\u00");
if (c < 0x10)
{
buf.append('0');
}
buf.append(Integer.toString(c,16)); // hex
}
else
{
// normal escape
buf.append('\\').append(escaped);
}
}
}
}
/**
* Simple quote of a string, escaping where needed.
*
* @param buf
* the StringBuilder to append to
* @param str
* the string to quote
*/
public static void quote(StringBuilder buf, String str)
{
buf.append('"');
escape(buf,str);
buf.append('"');
}
/**
* Append into buf the provided string, adding quotes if needed.
*
* Quoting is determined if any of the characters in the delim are found in the input str.
*
* @param buf
* the buffer to append to
* @param str
* the string to possibly quote
* @param delim
* the delimiter characters that will trigger automatic quoting
* @throws IOException
*/
public static void quoteIfNeeded(StringBuilder buf, String str, String delim)
{
// check for delimiters in input string
int len = str.length();
int ch;
for (int i = 0; i < len; i++)
{
ch = str.codePointAt(i);
if (delim.indexOf(ch) >= 0)
{
// found a delimiter codepoint. we need to quote it.
quote(buf,str);
return;
}
}
// no special delimiters used, no quote needed.
buf.append(str);
}
/**
* Create an iterator of the input string, breaking apart the string at the provided delimiters, removing quotes and triming the parts of the string as
* needed.
*
* @param str
* the input string to split apart
* @param delims
* the delimiter characters to split the string on
* @return the iterator of the parts of the string, trimmed, with quotes around the string part removed, and unescaped
*/
public static Iterator splitAt(String str, String delims)
{
return new DeQuotingStringIterator(str.trim(),delims);
}
public static String unescape(String str)
{
if (str == null)
{
// nothing there
return null;
}
int len = str.length();
if (len <= 1)
{
// impossible to be escaped
return str;
}
StringBuilder ret = new StringBuilder(len - 2);
boolean escaped = false;
char c;
for (int i = 0; i < len; i++)
{
c = str.charAt(i);
if (escaped)
{
escaped = false;
switch (c)
{
case 'n':
ret.append('\n');
break;
case 'r':
ret.append('\r');
break;
case 't':
ret.append('\t');
break;
case 'f':
ret.append('\f');
break;
case 'b':
ret.append('\b');
break;
case '\\':
ret.append('\\');
break;
case '/':
ret.append('/');
break;
case '"':
ret.append('"');
break;
case 'u':
ret.append((char)((dehex((byte)str.charAt(i++)) << 24) + (dehex((byte)str.charAt(i++)) << 16) + (dehex((byte)str.charAt(i++)) << 8) + (dehex((byte)str
.charAt(i++)))));
break;
default:
ret.append(c);
}
}
else if (c == '\\')
{
escaped = true;
}
else
{
ret.append(c);
}
}
return ret.toString();
}
}