/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package groovy.json;
import org.apache.groovy.io.
StringBuilderWriter;
import java.io.
IOException;
import java.io.
Writer;
import java.util.
Locale;
/**
* Escapes and unescapes <code>String</code>s for
* Java, Java Script, HTML, XML, and SQL.
* <p>
* #ThreadSafe#
* <p>
* <b>Note that this version is a stripped down version from Commons Lang 2.6 with only necessary methods for
* JSON builder</b>
* @author Apache Software Foundation
* @author Apache Jakarta Turbine
* @author Purple Technology
* @author <a href="mailto:alex@purpletech.com">Alexander Day Chaffee</a>
* @author Antony Riley
* @author Helge Tesgaard
* @author <a href="sean@boohai.com">Sean Brown</a>
* @author <a href="mailto:ggregory@seagullsw.com">Gary Gregory</a>
* @author Phil Steitz
* @author Pete Gieser
* @since 2.0
*/
public class
StringEscapeUtils {
/**
* <p><code>StringEscapeUtils</code> instances should NOT be constructed in
* standard programming.
*
* <p>Instead, the class should be used as:
* <pre>StringEscapeUtils.escapeJava("foo");</pre>
*
* <p>This constructor is public to permit tools that require a JavaBean
* instance to operate.
*/
public
StringEscapeUtils() {
super();
}
// Java and JavaScript
//--------------------------------------------------------------------------
/**
* Escapes the characters in a <code>String</code> using Java String rules.
* <p>
* Deals correctly with quotes and control-chars (tab, backslash, cr, ff, etc.)
* <p>
* So a tab becomes the characters <code>'\\'</code> and <code>'t'</code>.
* <p>
* The only difference between Java strings and JavaScript strings
* is that in JavaScript, a single quote must be escaped.
* <p>
* Example:
* <pre>
* input string: He didn't say, "Stop!"
* output string: He didn't say, \"Stop!\"
* </pre>
*
* @param str String to escape values in, may be null
* @return String with escaped values, <code>null</code> if null string input
*/
public static
String escapeJava(
String str) {
return
escapeJavaStyleString(
str, false, false);
}
/**
* Escapes the characters in a <code>String</code> using Java String rules to
* a <code>Writer</code>.
* <p>
* A <code>null</code> string input has no effect.
*
* @see #escapeJava(java.lang.String)
* @param out Writer to write escaped string into
* @param str String to escape values in, may be null
* @throws IllegalArgumentException if the Writer is <code>null</code>
* @throws IOException if error occurs on underlying Writer
*/
public static void
escapeJava(
Writer out,
String str) throws
IOException {
escapeJavaStyleString(
out,
str, false, false);
}
/**
* Escapes the characters in a <code>String</code> using JavaScript String rules.
* <p>
* Escapes any values it finds into their JavaScript String form.
* Deals correctly with quotes and control-chars (tab, backslash, cr, ff, etc.)
* <p>
* So a tab becomes the characters <code>'\\'</code> and <code>'t'</code>.
* <p>
* The only difference between Java strings and JavaScript strings
* is that in JavaScript, a single quote must be escaped.
* <p>
* Example:
* <pre>
* input string: He didn't say, "Stop!"
* output string: He didn\'t say, \"Stop!\"
* </pre>
*
* @param str String to escape values in, may be null
* @return String with escaped values, <code>null</code> if null string input
*/
public static
String escapeJavaScript(
String str) {
return
escapeJavaStyleString(
str, true, true);
}
/**
* Escapes the characters in a <code>String</code> using JavaScript String rules
* to a <code>Writer</code>.
* <p>
* A <code>null</code> string input has no effect.
*
* @see #escapeJavaScript(java.lang.String)
* @param out Writer to write escaped string into
* @param str String to escape values in, may be null
* @throws IllegalArgumentException if the Writer is <code>null</code>
* @throws IOException if error occurs on underlying Writer
**/
public static void
escapeJavaScript(
Writer out,
String str) throws
IOException {
escapeJavaStyleString(
out,
str, true, true);
}
/**
* Worker method for the {@link #escapeJavaScript(String)} method.
*
* @param str String to escape values in, may be null
* @param escapeSingleQuotes escapes single quotes if <code>true</code>
* @param escapeForwardSlash TODO
* @return the escaped string
*/
private static
String escapeJavaStyleString(
String str, boolean
escapeSingleQuotes, boolean
escapeForwardSlash) {
if (
str == null) {
return null;
}
try {
Writer writer = new
StringBuilderWriter(
str.
length() * 2);
escapeJavaStyleString(
writer,
str,
escapeSingleQuotes,
escapeForwardSlash);
return
writer.
toString();
} catch (
IOException ioe) {
// this should never ever happen while writing to a StringBuilderWriter
throw new
RuntimeException(
ioe);
}
}
/**
* Worker method for the {@link #escapeJavaScript(String)} method.
*
* @param out writer to receive the escaped string
* @param str String to escape values in, may be null
* @param escapeSingleQuote escapes single quotes if <code>true</code>
* @param escapeForwardSlash TODO
* @throws IOException if an IOException occurs
*/
private static void
escapeJavaStyleString(
Writer out,
String str, boolean
escapeSingleQuote,
boolean
escapeForwardSlash) throws
IOException {
if (
out == null) {
throw new
IllegalArgumentException("The Writer must not be null");
}
if (
str == null) {
return;
}
int
sz;
sz =
str.
length();
for (int
i = 0;
i <
sz;
i++) {
char
ch =
str.
charAt(
i);
// handle unicode
if (
ch > 0xfff) {
out.
write("\\u" +
hex(
ch));
} else if (
ch > 0xff) {
out.
write("\\u0" +
hex(
ch));
} else if (
ch > 0x7f) {
out.
write("\\u00" +
hex(
ch));
} else if (
ch < 32) {
switch (
ch) {
case '\b':
out.
write('\\');
out.
write('b');
break;
case '\n':
out.
write('\\');
out.
write('n');
break;
case '\t':
out.
write('\\');
out.
write('t');
break;
case '\f':
out.
write('\\');
out.
write('f');
break;
case '\r':
out.
write('\\');
out.
write('r');
break;
default:
if (
ch > 0xf) {
out.
write("\\u00" +
hex(
ch));
} else {
out.
write("\\u000" +
hex(
ch));
}
break;
}
} else {
switch (
ch) {
case '\'':
if (
escapeSingleQuote) {
out.
write('\\');
}
out.
write('\'');
break;
case '"':
out.
write('\\');
out.
write('"');
break;
case '\\':
out.
write('\\');
out.
write('\\');
break;
case '/':
if (
escapeForwardSlash) {
out.
write('\\');
}
out.
write('/');
break;
default:
out.
write(
ch);
break;
}
}
}
}
/**
* Returns an upper case hexadecimal <code>String</code> for the given
* character.
*
* @param ch The character to convert.
* @return An upper case hexadecimal <code>String</code>
*/
private static
String hex(char
ch) {
return
Integer.
toHexString(
ch).
toUpperCase(
Locale.
ENGLISH);
}
/**
* Unescapes any Java literals found in the <code>String</code>.
* For example, it will turn a sequence of <code>'\'</code> and
* <code>'n'</code> into a newline character, unless the <code>'\'</code>
* is preceded by another <code>'\'</code>.
*
* @param str the <code>String</code> to unescape, may be null
* @return a new unescaped <code>String</code>, <code>null</code> if null string input
*/
public static
String unescapeJava(
String str) {
if (
str == null) {
return null;
}
try {
Writer writer = new
StringBuilderWriter(
str.
length());
unescapeJava(
writer,
str);
return
writer.
toString();
} catch (
IOException ioe) {
// this should never ever happen while writing to a StringBuilderWriter
throw new
RuntimeException(
ioe);
}
}
/**
* <p>Unescapes any Java literals found in the <code>String</code> to a
* <code>Writer</code>.
* <p>
* For example, it will turn a sequence of <code>'\'</code> and
* <code>'n'</code> into a newline character, unless the <code>'\'</code>
* is preceded by another <code>'\'</code>.
* <p>
* A <code>null</code> string input has no effect.
*
* @param out the <code>Writer</code> used to output unescaped characters
* @param str the <code>String</code> to unescape, may be null
* @throws IllegalArgumentException if the Writer is <code>null</code>
* @throws IOException if error occurs on underlying Writer
*/
public static void
unescapeJava(
Writer out,
String str) throws
IOException {
if (
out == null) {
throw new
IllegalArgumentException("The Writer must not be null");
}
if (
str == null) {
return;
}
int
sz =
str.
length();
StringBuilder unicode = new
StringBuilder(4);
boolean
hadSlash = false;
boolean
inUnicode = false;
for (int
i = 0;
i <
sz;
i++) {
char
ch =
str.
charAt(
i);
if (
inUnicode) {
// if in unicode, then we're reading unicode
// values in somehow
unicode.
append(
ch);
if (
unicode.
length() == 4) {
// unicode now contains the four hex digits
// which represents our unicode character
try {
int
value =
Integer.
parseInt(
unicode.
toString(), 16);
out.
write((char)
value);
unicode.
setLength(0);
inUnicode = false;
hadSlash = false;
} catch (
NumberFormatException nfe) {
throw new
RuntimeException("Unable to parse unicode value: " +
unicode,
nfe);
}
}
continue;
}
if (
hadSlash) {
// handle an escaped value
hadSlash = false;
switch (
ch) {
case '\\':
out.
write('\\');
break;
case '\'':
out.
write('\'');
break;
case '\"':
out.
write('"');
break;
case 'r':
out.
write('\r');
break;
case 'f':
out.
write('\f');
break;
case 't':
out.
write('\t');
break;
case 'n':
out.
write('\n');
break;
case 'b':
out.
write('\b');
break;
case 'u':
{
// uh-oh, we're in unicode country....
inUnicode = true;
break;
}
default :
out.
write(
ch);
break;
}
continue;
} else if (
ch == '\\') {
hadSlash = true;
continue;
}
out.
write(
ch);
}
if (
hadSlash) {
// then we're in the weird case of a \ at the end of the
// string, let's output it anyway.
out.
write('\\');
}
}
/**
* Unescapes any JavaScript literals found in the <code>String</code>.
* <p>
* For example, it will turn a sequence of <code>'\'</code> and <code>'n'</code>
* into a newline character, unless the <code>'\'</code> is preceded by another
* <code>'\'</code>.
*
* @see #unescapeJava(String)
* @param str the <code>String</code> to unescape, may be null
* @return A new unescaped <code>String</code>, <code>null</code> if null string input
*/
public static
String unescapeJavaScript(
String str) {
return
unescapeJava(
str);
}
/**
* Unescapes any JavaScript literals found in the <code>String</code> to a
* <code>Writer</code>.
* <p>
* For example, it will turn a sequence of <code>'\'</code> and <code>'n'</code>
* into a newline character, unless the <code>'\'</code> is preceded by another
* <code>'\'</code>.
* <p>
* A <code>null</code> string input has no effect.
*
* @see #unescapeJava(Writer,String)
* @param out the <code>Writer</code> used to output unescaped characters
* @param str the <code>String</code> to unescape, may be null
* @throws IllegalArgumentException if the Writer is <code>null</code>
* @throws IOException if error occurs on underlying Writer
*/
public static void
unescapeJavaScript(
Writer out,
String str) throws
IOException {
unescapeJava(
out,
str);
}
}