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////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Copyright (c) 2015 Saxonica Limited.
// This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0.
// If a copy of the MPL was not distributed with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
// This Source Code Form is "Incompatible With Secondary Licenses", as defined by the Mozilla Public License, v. 2.0.
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
package net.sf.saxon.om;
import net.sf.saxon.serialize.charcode.UTF16CharacterSet;
import net.sf.saxon.serialize.charcode.XMLCharacterData;
import net.sf.saxon.trans.Err;
import net.sf.saxon.trans.XPathException;
/**
* The NameChecker performs validation and analysis of XML names.
*
* In releases prior to 9.6, there were two name checkers, one for XML 1.0 and
* one for XML 1.1. However, XML 1.0 fifth edition uses the same rules for XML names
* as XML 1.1, so they were actually checking the same rules for names (although they
* were different when checking for valid characters). From 9.6, the name checker
* no longer performs checks for valid XML characters, so only one name checker is
* needed, and the methods have become static.
*/
public abstract class NameChecker {
/**
* Validate whether a given string constitutes a valid QName, as defined in XML Namespaces.
* Note that this does not test whether the prefix is actually declared.
*
* @param name the name to be tested
* @return true if the name is a lexically-valid QName
*/
public static boolean isQName(String name) {
int colon = name.indexOf(':');
if (colon < 0) {
return isValidNCName(name);
}
return colon != 0 &&
colon != name.length() - 1 &&
isValidNCName(name.substring(0, colon)) &&
isValidNCName(name.substring(colon + 1));
}
/**
* Extract the prefix from a QName. Note, the QName is assumed to be valid.
*
* @param qname The lexical QName whose prefix is required
* @return the prefix, that is the part before the colon. Returns an empty
* string if there is no prefix
*/
public static String getPrefix(String qname) {
int colon = qname.indexOf(':');
if (colon < 0) {
return "";
}
return qname.substring(0, colon);
}
/**
* Validate a QName, and return the prefix and local name. The local name is checked
* to ensure it is a valid NCName. The prefix is not checked, on the theory that the caller
* will look up the prefix to find a URI, and if the prefix is invalid, then no URI will
* be found.
*
* @param qname the lexical QName whose parts are required. Note that leading and trailing
* whitespace is not permitted
* @return an array of two strings, the prefix and the local name. The first
* item is a zero-length string if there is no prefix.
* @throws QNameException if not a valid QName.
*/
public static String[] getQNameParts(CharSequence qname) throws QNameException {
String[] parts = new String[2];
int colon = -1;
int len = qname.length();
for (int i = 0; i < len; i++) {
if (qname.charAt(i) == ':') {
colon = i;
break;
}
}
if (colon < 0) {
parts[0] = "";
parts[1] = qname.toString();
if (!isValidNCName(parts[1])) {
throw new QNameException("Invalid QName " + Err.wrap(qname));
}
} else {
if (colon == 0) {
throw new QNameException("QName cannot start with colon: " + Err.wrap(qname));
}
if (colon == len - 1) {
throw new QNameException("QName cannot end with colon: " + Err.wrap(qname));
}
parts[0] = qname.subSequence(0, colon).toString();
parts[1] = qname.subSequence(colon + 1, len).toString();
if (!isValidNCName(parts[1])) {
if (!isValidNCName(parts[0])) {
throw new QNameException("Both the prefix " + Err.wrap(parts[0]) +
" and the local part " + Err.wrap(parts[1]) + " are invalid");
}
throw new QNameException("Invalid QName local part " + Err.wrap(parts[1]));
}
}
return parts;
}
/**
* Validate a QName, and return the prefix and local name. Both parts are checked
* to ensure they are valid NCNames.
*
* Used from compiled code
*
* @param qname the lexical QName whose parts are required. Note that leading and trailing
* whitespace is not permitted
* @return an array of two strings, the prefix and the local name. The first
* item is a zero-length string if there is no prefix.
* @throws XPathException if not a valid QName.
*/
/*@NotNull*/
public static String[] checkQNameParts(CharSequence qname) throws XPathException {
try {
String[] parts = getQNameParts(qname);
if (parts[0].length() > 0 && !isValidNCName(parts[0])) {
throw new XPathException("Invalid QName prefix " + Err.wrap(parts[0]));
}
return parts;
} catch (QNameException e) {
XPathException err = new XPathException(e.getMessage());
err.setErrorCode("FORG0001");
throw err;
}
}
/**
* Validate whether a given string constitutes a valid NCName, as defined in XML Namespaces.
*
* @param ncName the name to be tested. Any whitespace trimming must have already been applied.
* @return true if the name is a lexically-valid QName
*/
public static boolean isValidNCName(CharSequence ncName) {
if (ncName.length() == 0) {
return false;
}
int s = 1;
char ch = ncName.charAt(0);
if (UTF16CharacterSet.isHighSurrogate(ch)) {
if (!isNCNameStartChar(UTF16CharacterSet.combinePair(ch, ncName.charAt(1)))) {
return false;
}
s = 2;
} else {
if (!isNCNameStartChar(ch)) {
return false;
}
}
for (int i = s; i < ncName.length(); i++) {
ch = ncName.charAt(i);
if (UTF16CharacterSet.isHighSurrogate(ch)) {
if (!isNCNameChar(UTF16CharacterSet.combinePair(ch, ncName.charAt(++i)))) {
return false;
}
} else {
if (!isNCNameChar(ch)) {
return false;
}
}
}
return true;
}
/**
* Check to see if a string is a valid Nmtoken according to [7]
* in the XML 1.0 Recommendation
*
* @param nmtoken the string to be tested. Any whitespace trimming must have already been applied.
* @return true if nmtoken is a valid Nmtoken
*/
public static boolean isValidNmtoken(CharSequence nmtoken) {
if (nmtoken.length() == 0) {
return false;
}
for (int i = 0; i < nmtoken.length(); i++) {
char ch = nmtoken.charAt(i);
if (UTF16CharacterSet.isHighSurrogate(ch)) {
if (!isNCNameChar(UTF16CharacterSet.combinePair(ch, nmtoken.charAt(++i)))) {
return false;
}
} else {
if (ch != ':' && !isNCNameChar(ch)) {
return false;
}
}
}
return true;
}
/**
* Test whether a character can appear in an NCName
*
* @param ch the character to be tested
* @return true if this is a valid character in an NCName. The rules for XML 1.0 fifth
* edition are the same as the XML 1.1 rules, and these are the rules that we use.
*/
public static boolean isNCNameChar(int ch) {
return XMLCharacterData.isNCName11(ch);
}
/**
* Test whether a character can appear at the start of an NCName
*
* @param ch the character to be tested
* @return true if this is a valid character at the start of an NCName. The rules for XML 1.0 fifth
* edition are the same as the XML 1.1 rules, and these are the rules that we use.
*/
public static boolean isNCNameStartChar(int ch) {
return XMLCharacterData.isNCNameStart11(ch);
}
}
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