U4-1611 - fix xpath special chars escaping issues in published content store

src/Umbraco.Core/Xml/DynamicContext.cs

@@ -0,0 +1,312 @@
+using System;
+using System.Collections.Generic;
+using System.Xml;
+using System.Xml.Xsl;
+using System.Xml.XPath;
+
+// source: mvpxml.codeplex.com
+
+namespace Umbraco.Core.Xml
+{
+	/// <summary>
+	/// Provides the evaluation context for fast execution and custom 
+	/// variables resolution.
+	/// </summary>
+	/// <remarks>
+	/// This class is responsible for resolving variables during dynamic expression execution.
+	/// <para>Discussed in http://weblogs.asp.net/cazzu/archive/2003/10/07/30888.aspx</para>
+	/// <para>Author: Daniel Cazzulino, <a href="http://clariusconsulting.net/kzu">blog</a></para>
+	/// </remarks>
+	public class DynamicContext : XsltContext
+	{
+		#region Private vars
+
+	    readonly IDictionary<string, IXsltContextVariable> _variables =
+			new Dictionary<string, IXsltContextVariable>();
+
+		#endregion Private
+
+		#region Constructors & Initialization
+
+		/// <summary>
+		/// Initializes a new instance of the <see cref="DynamicContext"/> class.
+		/// </summary>
+		public DynamicContext()
+			: base(new NameTable())
+		{
+		}
+
+		/// <summary>
+		/// Initializes a new instance of the <see cref="DynamicContext"/> 
+		/// class with the specified <see cref="NameTable"/>.
+		/// </summary>
+		/// <param name="table">The NameTable to use.</param>
+		public DynamicContext(NameTable table)
+			: base(table)
+		{
+		}
+
+		/// <summary>
+		/// Initializes a new instance of the <see cref="DynamicContext"/> class.
+		/// </summary>
+		/// <param name="context">A previously filled context with the namespaces to use.</param>
+		public DynamicContext(XmlNamespaceManager context)
+			: this(context, new NameTable())
+		{
+		}
+
+		/// <summary>
+		/// Initializes a new instance of the <see cref="DynamicContext"/> class.
+		/// </summary>
+		/// <param name="context">A previously filled context with the namespaces to use.</param>
+		/// <param name="table">The NameTable to use.</param>
+		public DynamicContext(XmlNamespaceManager context, NameTable table)
+			: base(table)
+		{
+			object xml = table.Add(XmlNamespaces.Xml);
+			object xmlns = table.Add(XmlNamespaces.XmlNs);
+
+		    if (context == null) return;
+
+		    foreach (string prefix in context)
+		    {
+		        var uri = context.LookupNamespace(prefix);
+		        // Use fast object reference comparison to omit forbidden namespace declarations.
+		        if (Equals(uri, xml) || Equals(uri, xmlns))
+		            continue;
+		        if (uri == null)
+		            continue;
+		        base.AddNamespace(prefix, uri);
+		    }
+		}
+
+		#endregion Constructors & Initialization
+
+		#region Common Overrides
+
+		/// <summary>
+		/// Implementation equal to <see cref="XsltContext"/>.
+		/// </summary>
+		public override int CompareDocument(string baseUri, string nextbaseUri)
+		{
+			return String.Compare(baseUri, nextbaseUri, false, System.Globalization.CultureInfo.InvariantCulture);
+		}
+
+		/// <summary>
+		/// Same as <see cref="XmlNamespaceManager"/>.
+		/// </summary>
+		public override string LookupNamespace(string prefix)
+		{
+		    var key = NameTable.Get(prefix);
+		    return key == null ? null : base.LookupNamespace(key);
+		}
+
+	    /// <summary>
+		/// Same as <see cref="XmlNamespaceManager"/>.
+		/// </summary>
+		public override string LookupPrefix(string uri)
+		{
+		    var key = NameTable.Get(uri);
+		    return key == null ? null : base.LookupPrefix(key);
+		}
+
+	    /// <summary>
+		/// Same as <see cref="XsltContext"/>.
+		/// </summary>
+		public override bool PreserveWhitespace(XPathNavigator node)
+		{
+			return true;
+		}
+
+		/// <summary>
+		/// Same as <see cref="XsltContext"/>.
+		/// </summary>
+		public override bool Whitespace
+		{
+			get { return true; }
+		}
+
+		#endregion Common Overrides
+
+		#region Public Members
+
+		/// <summary>
+		/// Shortcut method that compiles an expression using an empty navigator.
+		/// </summary>
+		/// <param name="xpath">The expression to compile</param>
+		/// <returns>A compiled <see cref="XPathExpression"/>.</returns>
+		public static XPathExpression Compile(string xpath)
+		{
+			return new XmlDocument().CreateNavigator().Compile(xpath);
+		}
+
+		#endregion Public Members
+
+		#region Variable Handling Code
+
+		/// <summary>
+		/// Adds the variable to the dynamic evaluation context.
+		/// </summary>
+		/// <param name="name">The name of the variable to add to the context.</param>
+		/// <param name="value">The value of the variable to add to the context.</param>
+		/// <remarks>
+		/// Value type conversion for XPath evaluation is as follows:
+		/// <list type="table">
+		///		<listheader>
+		///			<term>CLR Type</term>
+		///			<description>XPath type</description>
+		///		</listheader>
+		///		<item>
+		///			<term>System.String</term>
+		///			<description>XPathResultType.String</description>
+		///		</item>
+		///		<item>
+		///			<term>System.Double (or types that can be converted to)</term>
+		///			<description>XPathResultType.Number</description>
+		///		</item>
+		///		<item>
+		///			<term>System.Boolean</term>
+		///			<description>XPathResultType.Boolean</description>
+		///		</item>
+		///		<item>
+		///			<term>System.Xml.XPath.XPathNavigator</term>
+		///			<description>XPathResultType.Navigator</description>
+		///		</item>
+		///		<item>
+		///			<term>System.Xml.XPath.XPathNodeIterator</term>
+		///			<description>XPathResultType.NodeSet</description>
+		///		</item>
+		///		<item>
+		///			<term>Others</term>
+		///			<description>XPathResultType.Any</description>
+		///		</item>
+		/// </list>
+		/// <note type="note">See the topic "Compile, Select, Evaluate, and Matches with 
+		/// XPath and XPathExpressions" in MSDN documentation for additional information.</note>
+		/// </remarks>
+		/// <exception cref="ArgumentNullException">The <paramref name="value"/> is null.</exception>
+		public void AddVariable(string name, object value)
+		{
+			if (value == null) throw new ArgumentNullException("value");
+			_variables[name] = new DynamicVariable(name, value);
+		}
+
+		/// <summary>
+		/// See <see cref="XsltContext"/>. Not used in our implementation.
+		/// </summary>
+		public override IXsltContextFunction ResolveFunction(string prefix, string name, XPathResultType[] argTypes)
+		{
+			return null;
+		}
+
+		/// <summary>
+		/// Resolves the dynamic variables added to the context. See <see cref="XsltContext"/>. 
+		/// </summary>
+		public override IXsltContextVariable ResolveVariable(string prefix, string name)
+		{
+			IXsltContextVariable var;
+			_variables.TryGetValue(name, out var);
+			return var;
+		}
+
+		#endregion Variable Handling Code
+
+		#region Internal DynamicVariable class
+
+		/// <summary>
+		/// Represents a variable during dynamic expression execution.
+		/// </summary>
+		internal class DynamicVariable : IXsltContextVariable
+		{
+		    readonly string _name;
+		    readonly object _value;
+
+			#region Public Members
+
+            public string Name { get { return _name; } }
+
+			/// <summary>
+			/// Initializes a new instance of the class.
+			/// </summary>
+			/// <param name="name">The name of the variable.</param>
+			/// <param name="value">The value of the variable.</param>
+			public DynamicVariable(string name, object value)
+			{
+
+				_name = name;
+				_value = value;
+
+				if (value is String)
+					_type = XPathResultType.String;
+				else if (value is bool)
+					_type = XPathResultType.Boolean;
+				else if (value is XPathNavigator)
+					_type = XPathResultType.Navigator;
+				else if (value is XPathNodeIterator)
+					_type = XPathResultType.NodeSet;
+				else
+				{
+					// Try to convert to double (native XPath numeric type)
+					if (value is double)
+					{
+						_type = XPathResultType.Number;
+					}
+					else
+					{
+						if (value is IConvertible)
+						{
+							try
+							{
+								_value = Convert.ToDouble(value);
+								// We suceeded, so it's a number.
+								_type = XPathResultType.Number;
+							}
+							catch (FormatException)
+							{
+								_type = XPathResultType.Any;
+							}
+							catch (OverflowException)
+							{
+								_type = XPathResultType.Any;
+							}
+						}
+						else
+						{
+							_type = XPathResultType.Any;
+						}
+					}
+				}
+			}
+
+			#endregion Public Members
+
+			#region IXsltContextVariable Implementation
+
+			XPathResultType IXsltContextVariable.VariableType
+			{
+				get { return _type; }
+			}
+
+		    readonly XPathResultType _type;
+
+			object IXsltContextVariable.Evaluate(XsltContext context)
+			{
+				return _value;
+			}
+
+			bool IXsltContextVariable.IsLocal
+			{
+				get { return false; }
+			}
+
+			bool IXsltContextVariable.IsParam
+			{
+				get { return false; }
+			}
+
+			#endregion IXsltContextVariable Implementation
+		}
+
+		#endregion Internal DynamicVariable class
+	}
+}