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//------------------------------------------------------------------------------
// <copyright file="ValidateNames.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
// <owner current="true" primary="true">Microsoft</owner>
//------------------------------------------------------------------------------
using System;
#if !SILVERLIGHT
using System.Xml.XPath;
#endif
using System.Diagnostics;
using System.Globalization;
#if SILVERLIGHT_XPATH
namespace System.Xml.XPath {
#else
namespace System.Xml {
#endif
/// <summary>
/// Contains various static functions and methods for parsing and validating:
/// NCName (not namespace-aware, no colons allowed)
/// QName (prefix:local-name)
/// </summary>
internal static class ValidateNames {
internal enum Flags {
NCNames = 0x1, // Validate that each non-empty prefix and localName is a valid NCName
CheckLocalName = 0x2, // Validate the local-name
CheckPrefixMapping = 0x4, // Validate the prefix --> namespace mapping
All = 0x7,
AllExceptNCNames = 0x6,
AllExceptPrefixMapping = 0x3,
};
static XmlCharType xmlCharType = XmlCharType.Instance;
#if !SILVERLIGHT
//-----------------------------------------------
// Nmtoken parsing
//-----------------------------------------------
/// <summary>
/// Attempts to parse the input string as an Nmtoken (see the XML spec production [7] && XML Namespaces spec).
/// Quits parsing when an invalid Nmtoken char is reached or the end of string is reached.
/// Returns the number of valid Nmtoken chars that were parsed.
/// </summary>
internal static unsafe int ParseNmtoken(string s, int offset) {
Debug.Assert(s != null && offset <= s.Length);
// Keep parsing until the end of string or an invalid NCName character is reached
int i = offset;
while (i < s.Length) {
if ((xmlCharType.charProperties[s[i]] & XmlCharType.fNCNameSC) != 0) { // if (xmlCharType.IsNCNameSingleChar(s[i])) {
i++;
}
#if XML10_FIFTH_EDITION
else if (xmlCharType.IsNCNameSurrogateChar(s, i)) {
i += 2;
}
#endif
else {
break;
}
}
return i - offset;
}
#endif
//-----------------------------------------------
// Nmtoken parsing (no XML namespaces support)
//-----------------------------------------------
/// <summary>
/// Attempts to parse the input string as an Nmtoken (see the XML spec production [7]) without taking
/// into account the XML Namespaces spec. What it means is that the ':' character is allowed at any
/// position and any number of times in the token.
/// Quits parsing when an invalid Nmtoken char is reached or the end of string is reached.
/// Returns the number of valid Nmtoken chars that were parsed.
/// </summary>
#if SILVERLIGHT && !SILVERLIGHT_DISABLE_SECURITY && XMLCHARTYPE_USE_RESOURCE
[System.Security.SecuritySafeCritical]
#endif
internal static unsafe int ParseNmtokenNoNamespaces(string s, int offset) {
Debug.Assert(s != null && offset <= s.Length);
// Keep parsing until the end of string or an invalid Name character is reached
int i = offset;
while (i < s.Length) {
if ((xmlCharType.charProperties[s[i]] & XmlCharType.fNCNameSC) != 0 || s[i] == ':') { // if (xmlCharType.IsNameSingleChar(s[i])) {
i++;
}
#if XML10_FIFTH_EDITION
else if (xmlCharType.IsNCNameSurrogateChar(s, i)) {
i += 2;
}
#endif
else {
break;
}
}
return i - offset;
}
// helper methods
internal static bool IsNmtokenNoNamespaces(string s) {
int endPos = ParseNmtokenNoNamespaces(s, 0);
return endPos > 0 && endPos == s.Length;
}
//-----------------------------------------------
// Name parsing (no XML namespaces support)
//-----------------------------------------------
/// <summary>
/// Attempts to parse the input string as a Name without taking into account the XML Namespaces spec.
/// What it means is that the ':' character does not delimiter prefix and local name, but it is a regular
/// name character, which is allowed to appear at any position and any number of times in the name.
/// Quits parsing when an invalid Name char is reached or the end of string is reached.
/// Returns the number of valid Name chars that were parsed.
/// </summary>
#if SILVERLIGHT && !SILVERLIGHT_DISABLE_SECURITY && XMLCHARTYPE_USE_RESOURCE
[System.Security.SecuritySafeCritical]
#endif
internal static unsafe int ParseNameNoNamespaces(string s, int offset) {
Debug.Assert(s != null && offset <= s.Length);
// Quit if the first character is not a valid NCName starting character
int i = offset;
if (i < s.Length) {
if ((xmlCharType.charProperties[s[i]] & XmlCharType.fNCStartNameSC) != 0 || s[i] == ':') { // xmlCharType.IsStartNCNameSingleChar(s[i])) {
i++;
}
#if XML10_FIFTH_EDITION
else if (xmlCharType.IsNCNameSurrogateChar(s, i)) {
i += 2;
}
#endif
else {
return 0; // no valid StartNCName char
}
// Keep parsing until the end of string or an invalid NCName character is reached
while (i < s.Length) {
if ((xmlCharType.charProperties[s[i]] & XmlCharType.fNCNameSC) != 0 || s[i] == ':') { // if (xmlCharType.IsNCNameSingleChar(s[i]))
i++;
}
#if XML10_FIFTH_EDITION
else if (xmlCharType.IsNCNameSurrogateChar(s, i)) {
i += 2;
}
#endif
else {
break;
}
}
}
return i - offset;
}
// helper methods
internal static bool IsNameNoNamespaces(string s) {
int endPos = ParseNameNoNamespaces(s, 0);
return endPos > 0 && endPos == s.Length;
}
//-----------------------------------------------
// NCName parsing
//-----------------------------------------------
/// <summary>
/// Attempts to parse the input string as an NCName (see the XML Namespace spec).
/// Quits parsing when an invalid NCName char is reached or the end of string is reached.
/// Returns the number of valid NCName chars that were parsed.
/// </summary>
#if SILVERLIGHT && !SILVERLIGHT_DISABLE_SECURITY && XMLCHARTYPE_USE_RESOURCE
[System.Security.SecuritySafeCritical]
#endif
internal static unsafe int ParseNCName(string s, int offset) {
Debug.Assert(s != null && offset <= s.Length);
// Quit if the first character is not a valid NCName starting character
int i = offset;
if (i < s.Length) {
if ((xmlCharType.charProperties[s[i]] & XmlCharType.fNCStartNameSC) != 0) { // xmlCharType.IsStartNCNameSingleChar(s[i])) {
i++;
}
#if XML10_FIFTH_EDITION
else if (xmlCharType.IsNCNameSurrogateChar(s, i)) {
i += 2;
}
#endif
else {
return 0; // no valid StartNCName char
}
// Keep parsing until the end of string or an invalid NCName character is reached
while (i < s.Length) {
if ((xmlCharType.charProperties[s[i]] & XmlCharType.fNCNameSC) != 0) { // if (xmlCharType.IsNCNameSingleChar(s[i]))
i++;
}
#if XML10_FIFTH_EDITION
else if (xmlCharType.IsNCNameSurrogateChar(s, i)) {
i += 2;
}
#endif
else {
break;
}
}
}
return i - offset;
}
internal static int ParseNCName(string s) {
return ParseNCName(s, 0);
}
/// <summary>
/// Calls parseName and throws exception if the resulting name is not a valid NCName.
/// Returns the input string if there is no error.
/// </summary>
internal static string ParseNCNameThrow(string s) {
// throwOnError = true
ParseNCNameInternal(s, true);
return s;
}
/// <summary>
/// Calls parseName and returns false or throws exception if the resulting name is not
/// a valid NCName. Returns the input string if there is no error.
/// </summary>
private static bool ParseNCNameInternal(string s, bool throwOnError) {
int len = ParseNCName(s, 0);
if (len == 0 || len != s.Length) {
// If the string is not a valid NCName, then throw or return false
if (throwOnError) ThrowInvalidName(s, 0, len);
return false;
}
return true;
}
//-----------------------------------------------
// QName parsing
//-----------------------------------------------
/// <summary>
/// Attempts to parse the input string as a QName (see the XML Namespace spec).
/// Quits parsing when an invalid QName char is reached or the end of string is reached.
/// Returns the number of valid QName chars that were parsed.
/// Sets colonOffset to the offset of a colon character if it exists, or 0 otherwise.
/// </summary>
internal static int ParseQName(string s, int offset, out int colonOffset) {
int len, lenLocal;
// Assume no colon
colonOffset = 0;
// Parse NCName (may be prefix, may be local name)
len = ParseNCName(s, offset);
if (len != 0) {
// Non-empty NCName, so look for colon if there are any characters left
offset += len;
if (offset < s.Length && s[offset] == ':') {
// First NCName was prefix, so look for local name part
lenLocal = ParseNCName(s, offset + 1);
if (lenLocal != 0) {
// Local name part found, so increase total QName length (add 1 for colon)
colonOffset = offset;
len += lenLocal + 1;
}
}
}
return len;
}
/// <summary>
/// Calls parseQName and throws exception if the resulting name is not a valid QName.
/// Returns the prefix and local name parts.
/// </summary>
internal static void ParseQNameThrow(string s, out string prefix, out string localName) {
int colonOffset;
int len = ParseQName(s, 0, out colonOffset);
if (len == 0 || len != s.Length) {
// If the string is not a valid QName, then throw
ThrowInvalidName(s, 0, len);
}
if (colonOffset != 0) {
prefix = s.Substring(0, colonOffset);
localName = s.Substring(colonOffset + 1);
}
else {
prefix = "";
localName = s;
}
}
#if !SILVERLIGHT
/// <summary>
/// Parses the input string as a NameTest (see the XPath spec), returning the prefix and
/// local name parts. Throws an exception if the given string is not a valid NameTest.
/// If the NameTest contains a star, null values for localName (case NCName':*'), or for
/// both localName and prefix (case '*') are returned.
/// </summary>
internal static void ParseNameTestThrow(string s, out string prefix, out string localName) {
int len, lenLocal, offset;
if (s.Length != 0 && s[0] == '*') {
// '*' as a NameTest
prefix = localName = null;
len = 1;
}
else {
// Parse NCName (may be prefix, may be local name)
len = ParseNCName(s, 0);
if (len != 0) {
// Non-empty NCName, so look for colon if there are any characters left
localName = s.Substring(0, len);
if (len < s.Length && s[len] == ':') {
// First NCName was prefix, so look for local name part
prefix = localName;
offset = len + 1;
if (offset < s.Length && s[offset] == '*') {
// '*' as a local name part, add 2 to len for colon and star
localName = null;
len += 2;
}
else {
lenLocal = ParseNCName(s, offset);
if (lenLocal != 0) {
// Local name part found, so increase total NameTest length
localName = s.Substring(offset, lenLocal);
len += lenLocal + 1;
}
}
}
else {
prefix = string.Empty;
}
}
else {
// Make the compiler happy
prefix = localName = null;
}
}
if (len == 0 || len != s.Length) {
// If the string is not a valid NameTest, then throw
ThrowInvalidName(s, 0, len);
}
}
#endif
/// <summary>
/// Throws an invalid name exception.
/// </summary>
/// <param name="s">String that was parsed.</param>
/// <param name="offsetStartChar">Offset in string where parsing began.</param>
/// <param name="offsetBadChar">Offset in string where parsing failed.</param>
internal static void ThrowInvalidName(string s, int offsetStartChar, int offsetBadChar) {
// If the name is empty, throw an exception
if (offsetStartChar >= s.Length)
#if !SILVERLIGHT_XPATH
throw new XmlException(Res.Xml_EmptyName, string.Empty);
#else
throw new XmlException(Res.GetString(Res.Xml_EmptyName, string.Empty));
#endif
Debug.Assert(offsetBadChar < s.Length);
if (xmlCharType.IsNCNameSingleChar(s[offsetBadChar]) && !XmlCharType.Instance.IsStartNCNameSingleChar(s[offsetBadChar])) {
// The error character is a valid name character, but is not a valid start name character
#if !SILVERLIGHT_XPATH
throw new XmlException(Res.Xml_BadStartNameChar, XmlException.BuildCharExceptionArgs(s, offsetBadChar));
#else
throw new XmlException(Res.GetString(Res.Xml_BadStartNameChar, XmlExceptionHelper.BuildCharExceptionArgs(s, offsetBadChar)));
#endif
}
else {
// The error character is an invalid name character
#if !SILVERLIGHT_XPATH
throw new XmlException(Res.Xml_BadNameChar, XmlException.BuildCharExceptionArgs(s, offsetBadChar));
#else
throw new XmlException(Res.GetString(Res.Xml_BadNameChar, XmlExceptionHelper.BuildCharExceptionArgs(s, offsetBadChar)));
#endif
}
}
#if !SILVERLIGHT
internal static Exception GetInvalidNameException(string s, int offsetStartChar, int offsetBadChar) {
// If the name is empty, throw an exception
if (offsetStartChar >= s.Length)
return new XmlException(Res.Xml_EmptyName, string.Empty);
Debug.Assert(offsetBadChar < s.Length);
if (xmlCharType.IsNCNameSingleChar(s[offsetBadChar]) && !xmlCharType.IsStartNCNameSingleChar(s[offsetBadChar])) {
// The error character is a valid name character, but is not a valid start name character
return new XmlException(Res.Xml_BadStartNameChar, XmlException.BuildCharExceptionArgs(s, offsetBadChar));
}
else {
// The error character is an invalid name character
return new XmlException(Res.Xml_BadNameChar, XmlException.BuildCharExceptionArgs(s, offsetBadChar));
}
}
/// <summary>
/// Returns true if "prefix" starts with the characters 'x', 'm', 'l' (case-insensitive).
/// </summary>
internal static bool StartsWithXml(string s) {
if (s.Length < 3)
return false;
if (s[0] != 'x' && s[0] != 'X')
return false;
if (s[1] != 'm' && s[1] != 'M')
return false;
if (s[2] != 'l' && s[2] != 'L')
return false;
return true;
}
/// <summary>
/// Returns true if "s" is a namespace that is reserved by Xml 1.0 or Namespace 1.0.
/// </summary>
internal static bool IsReservedNamespace(string s) {
return s.Equals(XmlReservedNs.NsXml) || s.Equals(XmlReservedNs.NsXmlNs);
}
/// <summary>
/// Throw if the specified name parts are not valid according to the rules of "nodeKind". Check only rules that are
/// specified by the Flags.
/// NOTE: Namespaces should be passed using a prefix, ns pair. "localName" is always string.Empty.
/// </summary>
internal static void ValidateNameThrow(string prefix, string localName, string ns, XPathNodeType nodeKind, Flags flags) {
// throwOnError = true
ValidateNameInternal(prefix, localName, ns, nodeKind, flags, true);
}
/// <summary>
/// Return false if the specified name parts are not valid according to the rules of "nodeKind". Check only rules that are
/// specified by the Flags.
/// NOTE: Namespaces should be passed using a prefix, ns pair. "localName" is always string.Empty.
/// </summary>
internal static bool ValidateName(string prefix, string localName, string ns, XPathNodeType nodeKind, Flags flags) {
// throwOnError = false
return ValidateNameInternal(prefix, localName, ns, nodeKind, flags, false);
}
/// <summary>
/// Return false or throw if the specified name parts are not valid according to the rules of "nodeKind". Check only rules
/// that are specified by the Flags.
/// NOTE: Namespaces should be passed using a prefix, ns pair. "localName" is always string.Empty.
/// </summary>
private static bool ValidateNameInternal(string prefix, string localName, string ns, XPathNodeType nodeKind, Flags flags, bool throwOnError) {
Debug.Assert(prefix != null && localName != null && ns != null);
if ((flags & Flags.NCNames) != 0) {
// 1. Verify that each non-empty prefix and localName is a valid NCName
if (prefix.Length != 0)
if (!ParseNCNameInternal(prefix, throwOnError)) {
return false;
}
if (localName.Length != 0)
if (!ParseNCNameInternal(localName, throwOnError)) {
return false;
}
}
if ((flags & Flags.CheckLocalName) != 0) {
// 2. Determine whether the local name is valid
switch (nodeKind) {
case XPathNodeType.Element:
// Elements and attributes must have a non-empty local name
if (localName.Length == 0) {
if (throwOnError) throw new XmlException(Res.Xdom_Empty_LocalName, string.Empty);
return false;
}
break;
case XPathNodeType.Attribute:
// Attribute local name cannot be "xmlns" if namespace is empty
if (ns.Length == 0 && localName.Equals("xmlns")) {
if (throwOnError) throw new XmlException(Res.XmlBadName, new string[] {nodeKind.ToString(), localName});
return false;
}
goto case XPathNodeType.Element;
case XPathNodeType.ProcessingInstruction:
// PI's local-name must be non-empty and cannot be 'xml' (case-insensitive)
if (localName.Length == 0 || (localName.Length == 3 && StartsWithXml(localName))) {
if (throwOnError) throw new XmlException(Res.Xml_InvalidPIName, localName);
return false;
}
break;
default:
// All other node types must have empty local-name
if (localName.Length != 0) {
if (throwOnError) throw new XmlException(Res.XmlNoNameAllowed, nodeKind.ToString());
return false;
}
break;
}
}
if ((flags & Flags.CheckPrefixMapping) != 0) {
// 3. Determine whether the prefix is valid
switch (nodeKind) {
case XPathNodeType.Element:
case XPathNodeType.Attribute:
case XPathNodeType.Namespace:
if (ns.Length == 0) {
// If namespace is empty, then prefix must be empty
if (prefix.Length != 0) {
if (throwOnError) throw new XmlException(Res.Xml_PrefixForEmptyNs, string.Empty);
return false;
}
}
else {
// Don't allow empty attribute prefix since namespace is non-empty
if (prefix.Length == 0 && nodeKind == XPathNodeType.Attribute) {
if (throwOnError) throw new XmlException(Res.XmlBadName, new string[] {nodeKind.ToString(), localName});
return false;
}
if (prefix.Equals("xml")) {
// xml prefix must be mapped to the xml namespace
if (!ns.Equals(XmlReservedNs.NsXml)) {
if (throwOnError) throw new XmlException(Res.Xml_XmlPrefix, string.Empty);
return false;
}
}
else if (prefix.Equals("xmlns")) {
// Prefix may never be 'xmlns'
if (throwOnError) throw new XmlException(Res.Xml_XmlnsPrefix, string.Empty);
return false;
}
else if (IsReservedNamespace(ns)) {
// Don't allow non-reserved prefixes to map to xml or xmlns namespaces
if (throwOnError) throw new XmlException(Res.Xml_NamespaceDeclXmlXmlns, string.Empty);
return false;
}
}
break;
case XPathNodeType.ProcessingInstruction:
// PI's prefix and namespace must be empty
if (prefix.Length != 0 || ns.Length != 0) {
if (throwOnError) throw new XmlException(Res.Xml_InvalidPIName, CreateName(prefix, localName));
return false;
}
break;
default:
// All other node types must have empty prefix and namespace
if (prefix.Length != 0 || ns.Length != 0) {
if (throwOnError) throw new XmlException(Res.XmlNoNameAllowed, nodeKind.ToString());
return false;
}
break;
}
}
return true;
}
/// <summary>
/// Creates a colon-delimited qname from prefix and local name parts.
/// </summary>
private static string CreateName(string prefix, string localName) {
return (prefix.Length != 0) ? prefix + ":" + localName : localName;
}
#endif
#if !SILVERLIGHT || SILVERLIGHT_XPATH
/// <summary>
/// Split a QualifiedName into prefix and localname, w/o any checking.
/// (Used for XmlReader/XPathNavigator MoveTo(name) methods)
/// </summary>
internal static void SplitQName(string name, out string prefix, out string lname) {
int colonPos = name.IndexOf(':');
if (-1 == colonPos) {
prefix = string.Empty;
lname = name;
}
else if (0 == colonPos || (name.Length-1) == colonPos) {
#if !SILVERLIGHT_XPATH
throw new ArgumentException(Res.GetString(Res.Xml_BadNameChar, XmlException.BuildCharExceptionArgs(':', '\0')), "name");
#else
throw new ArgumentException(Res.GetString(Res.Xml_BadNameChar, XmlExceptionHelper.BuildCharExceptionArgs(':', '\0')), "name");
#endif
}
else {
prefix = name.Substring(0, colonPos);
colonPos++; // move after colon
lname = name.Substring(colonPos, name.Length - colonPos);
}
}
#endif
}
#if SILVERLIGHT_XPATH
internal class XmlExceptionHelper
{
internal static string[] BuildCharExceptionArgs(string data, int invCharIndex)
{
return BuildCharExceptionArgs(data[invCharIndex], invCharIndex + 1 < data.Length ? data[invCharIndex + 1] : '\0');
}
internal static string[] BuildCharExceptionArgs(char[] data, int invCharIndex)
{
return BuildCharExceptionArgs(data, data.Length, invCharIndex);
}
internal static string[] BuildCharExceptionArgs(char[] data, int length, int invCharIndex)
{
Debug.Assert(invCharIndex < data.Length);
Debug.Assert(invCharIndex < length);
Debug.Assert(length <= data.Length);
return BuildCharExceptionArgs(data[invCharIndex], invCharIndex + 1 < length ? data[invCharIndex + 1] : '\0');
}
internal static string[] BuildCharExceptionArgs(char invChar, char nextChar)
{
string[] aStringList = new string[2];
// for surrogate characters include both high and low char in the message so that a full character is displayed
if (XmlCharType.IsHighSurrogate(invChar) && nextChar != 0)
{
int combinedChar = XmlCharType.CombineSurrogateChar(nextChar, invChar);
aStringList[0] = new string(new char[] { invChar, nextChar });
aStringList[1] = string.Format(CultureInfo.InvariantCulture, "0x{0:X2}", combinedChar);
}
else
{
// don't include 0 character in the string - in means eof-of-string in native code, where this may bubble up to
if ((int)invChar == 0)
{
aStringList[0] = ".";
}
else
{
aStringList[0] = invChar.ToString(CultureInfo.InvariantCulture);
}
aStringList[1] = string.Format(CultureInfo.InvariantCulture, "0x{0:X2}", (int)invChar);
}
return aStringList;
}
}
#endif
}
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