// WFS provider by Peter Robineau (peter.robineau@gmx.at)

// This file can be redistributed and/or modified under the terms of the GNU Lesser General Public License.

using System;

using System.Collections;

using System.Collections.Generic;

using System.Diagnostics;

using System.IO;

using System.Xml;

using System.Xml.XPath;

using System.Xml.Xsl;

namespace SharpMap.Utilities.Wfs

{

/// <summary>

/// This class provides an easy-to-use interface for complex (parameterized) XPath queries.

/// </summary>

public class XPathQueryManager : IXPathQueryManager

{

#region Fields

private int _NavDiff = -1;

private CustomQueryContext _ParamContext;

private XPathNodeIterator _XIter;

private XPathNavigator _XNav;

private XPathDocument _XPathDoc;

#endregion

#region Constructors

/// <summary>

/// Initializes a new instance of the <see cref="XPathQueryManager"/> class.

/// </summary>

public XPathQueryManager()

{

}

/// <summary>

/// Initializes a new instance of the <see cref="XPathQueryManager"/> class.

/// </summary>

/// <param name="documentStream">A Stream with XML data</param>

public XPathQueryManager(Stream documentStream)

{

SetDocumentToParse(documentStream);

}

/// <summary>

/// Initializes a new instance of the <see cref="XPathQueryManager"/> class.

/// </summary>

/// <param name="document">A byte array with XML data</param>

public XPathQueryManager(byte[] document)

{

SetDocumentToParse(document);

}

/// <summary>

/// Initializes a new instance of the <see cref="XPathQueryManager"/> class.

/// </summary>

/// <param name="xPathDoc">An XmlDocument instance</param>

public XPathQueryManager(XPathDocument xPathDoc)

{

SetDocumentToParse(xPathDoc);

_ParamContext = new CustomQueryContext(new NameTable());

}

/// <summary>

/// Initializes a new instance of the <see cref="XPathQueryManager"/> class.

/// </summary>

/// <param name="httpClientUtil">A configured <see cref="HttpClientUtil"/> instance for performing web requests</param>

public XPathQueryManager(HttpClientUtil httpClientUtil)

{

SetDocumentToParse(httpClientUtil);

}

/// <summary>

/// Initializes a new instance of the <see cref="XPathQueryManager"/> class.

/// </summary>

/// <param name="fileName"></param>

public XPathQueryManager(string fileName)

{

SetDocumentToParse(fileName);

}

/// <summary>

/// Initializes a new instance of the <see cref="XPathQueryManager"/> class.

/// </summary>

/// <param name="xPathDoc">An XmlDocument instance</param>

/// <param name="xNav">An <see cref="XPathNavigator"/> instance</param>

/// <param name="paramContext">A <see cref="XPathQueryManager.CustomQueryContext"/> instance for parameterized XPath expressions</param>

private XPathQueryManager(XPathDocument xPathDoc, XPathNavigator xNav, CustomQueryContext paramContext)

{

_XNav = xNav.Clone();

SetDocumentToParse(xPathDoc);

InitializeCustomContext(paramContext);

}

/// <summary>

/// Initializes a new instance of the <see cref="XPathQueryManager"/> class.

/// </summary>

/// <param name="xPathDoc">An XmlDocument instance</param>

/// <param name="xIter">An XPathNodeIterator instance</param>

/// <param name="paramContext">A <see cref="XPathQueryManager.CustomQueryContext"/> instance for parameterized XPath expressions</param>

private XPathQueryManager(XPathDocument xPathDoc, XPathNodeIterator xIter, CustomQueryContext paramContext)

: this(xPathDoc)

{

if (xIter != null)

_XNav = xIter.Current;

InitializeCustomContext(paramContext);

}

#endregion

#region IXPathQueryManager Member

/// <summary>

/// This method adds a namespace for XPath queries.

/// </summary>

/// <param name="prefix">The namespace prefix</param>

/// <param name="ns">The namespace URI</param>

public void AddNamespace(string prefix, string ns)

{

_ParamContext.AddNamespace(prefix, ns);

}

/// <summary>

/// This method compiles an XPath string.

/// </summary>

/// <param name="xPath">The XPath string</param>

/// <returns>A compiled XPath expression</returns>

public XPathExpression Compile(string xPath)

{

return _XNav.Compile(xPath);

}

/// <summary>

/// This method returns a clone of the current instance.

/// The cloned instance operates on the same (read-only) XmlDocument instance.

/// </summary>

public IXPathQueryManager Clone()

{

return new XPathQueryManager(_XPathDoc, _XNav, _ParamContext);

}

/// <summary>

/// This method returns an XPathNodeIterator instance positioned at the nodes

/// the XPath expression addresses.

/// </summary>

/// <param name="xPath">The compiled XPath expression</param>

public XPathNodeIterator GetIterator(XPathExpression xPath)

{

findXPath(xPath);

return _XIter.Clone();

}

/// <summary>

/// This method returns an XPathNodeIterator instance positioned at the nodes

/// the XPath expression addresses.

/// </summary>

/// <param name="xPath">The compiled XPath expression</param>

/// <param name="queryParameters">Parameters for the compiled XPath expression</param>

public XPathNodeIterator GetIterator(XPathExpression xPath, DictionaryEntry[] queryParameters)

{

_ParamContext.AddParam(queryParameters);

return GetIterator(xPath);

}

/// <summary>

/// This method returns the value of the first node the XPath expression addresses.

/// </summary>

/// <param name="xPath">The compiled XPath expression</param>

public string GetValueFromNode(XPathExpression xPath)

{

string result = null;

findXPath(xPath);

if (_XIter.MoveNext())

result = _XIter.Current.Value;

return result;

}

/// <summary>

/// This method returns the value of the first node the XPath expression addresses.

/// </summary>

/// <param name="xPath">The compiled XPath expression</param>

/// <param name="queryParameters">Parameters for the compiled XPath expression</param>

public string GetValueFromNode(XPathExpression xPath, DictionaryEntry[] queryParameters)

{

_ParamContext.AddParam(queryParameters);

return GetValueFromNode(xPath);

}

/// <summary>

/// This method returns a collection of the values of all nodes the XPath expression addresses.

/// </summary>

/// <param name="xPath">The compiled XPath expression</param>

public List<string> GetValuesFromNodes(XPathExpression xPath)

{

List<string> valuesList = new List<string>();

findXPath(xPath);

while (_XIter.MoveNext())

valuesList.Add(_XIter.Current.ToString());

return valuesList;

}

/// <summary>

/// This method returns a collection of the values of all nodes the XPath expression addresses.

/// </summary>

/// <param name="xPath">The compiled XPath expression</param>

/// <param name="queryParameters">Parameters for the compiled XPath expression</param>

public List<string> GetValuesFromNodes(XPathExpression xPath, DictionaryEntry[] queryParameters)

{

_ParamContext.AddParam(queryParameters);

return GetValuesFromNodes(xPath);

}

/// <summary>

/// This method returns an instance of <see cref="XPathQueryManager"/>

/// in the context of the first node the XPath expression addresses.

/// </summary>

/// <param name="xPath">The compiled XPath expression</param>

public IXPathQueryManager GetXPathQueryManagerInContext(XPathExpression xPath)

{

findXPath(xPath);

if (_XIter.MoveNext())

return new XPathQueryManager(_XPathDoc, _XIter, _ParamContext);

return null;

}

/// <summary>

/// This method returns an instance of <see cref="XPathQueryManager"/>

/// in the context of the first node the XPath expression addresses.

/// </summary>

/// <param name="xPath">The compiled XPath expression</param>

/// <param name="queryParameters">Parameters for the compiled XPath expression</param>

public IXPathQueryManager GetXPathQueryManagerInContext(XPathExpression xPath, DictionaryEntry[] queryParameters)

{

_ParamContext.AddParam(queryParameters);

findXPath(xPath);

if (_XIter.MoveNext())

return new XPathQueryManager(_XPathDoc, _XIter, _ParamContext);

return null;

}

/// <summary>

/// This method moves the current instance of <see cref="XPathQueryManager"/>

/// to the context of the next node a previously handed over XPath expression addresses.

/// </summary>

public bool GetContextOfNextNode()

{

return GetContextOfNode((uint) _NavDiff + 1);

}

/// <summary>

/// This method moves the current instance of <see cref="XPathQueryManager"/>

/// to the context of node[index] of current position.

/// </summary>

/// <param name="index">The index of the node to search</param>

public bool GetContextOfNode(uint index)

{

if (_NavDiff == -1) ++_NavDiff;

while (_NavDiff < index)

{

if (!_XNav.MoveToNext()) break;

_NavDiff++;

}

while (_NavDiff > index)

{

_XNav.MoveToPrevious();

_NavDiff--;

}

if (_NavDiff == index)

return true;

else

{

ResetNavigator();

return false;

}

}

/// <summary>

/// This method deletes the current namespace context.

/// </summary>

public void ResetNamespaces()

{

_ParamContext = null;

}

/// <summary>

/// This method resets the inherent XPathNavigator instance.

/// </summary>

public void ResetNavigator()

{

GetContextOfNode(0);

_NavDiff--;

}

/// <summary>

/// Sets a new XML document.

/// </summary>

/// <param name="documentStream">A Stream with XML data</param>

public void SetDocumentToParse(Stream documentStream)

{

initializeXPathObjects(documentStream);

}

/// <summary>

/// Sets a new XML document.

/// </summary>

/// <param name="document">A byte array with XML data</param>

public void SetDocumentToParse(byte[] document)

{

initializeXPathObjects(new MemoryStream(document));

}

/// <summary>

/// Sets a new XML document.

/// </summary>

/// <param name="httpClientUtil">A configured <see cref="HttpClientUtil"/> instance for performing web requests</param>

public void SetDocumentToParse(HttpClientUtil httpClientUtil)

{

try

{

initializeXPathObjects(httpClientUtil.GetDataStream());

}

finally

{

httpClientUtil.Close();

}

}

/// <summary>

/// Sets a new XmlDocument

/// </summary>

/// <param name="fileName"></param>

public void SetDocumentToParse(string fileName)

{

try

{

initializeXPathObjects(new FileStream(fileName, FileMode.Open, FileAccess.Read, FileShare.Read));

}

catch (Exception ex)

{

Trace.TraceError("An exception occured while reading the xml file: " + fileName);

throw ex;

}

}

#endregion

#region Private Member

/// <summary>

/// Sets a new XML document.

/// </summary>

/// <param name="xPathDoc">An XPathDocument instance</param>

private void SetDocumentToParse(XPathDocument xPathDoc)

{

_XPathDoc = xPathDoc;

if (_XNav == null) _XNav = _XPathDoc.CreateNavigator().Clone();

}

/// <summary>

/// This method does some XPath specific initializations.

/// </summary>

private void initializeXPathObjects(Stream xmlStream)

{

try

{

_XPathDoc = new XPathDocument(xmlStream);

_XNav = _XPathDoc.CreateNavigator();

_ParamContext = new CustomQueryContext(new NameTable());

}

catch (XmlException ex)

{

Trace.TraceError("An XML specific exception occured " +

"while initializing XPathDocument and XPathNavigator in XPathQueryManager: " +

ex.Message);

throw ex;

}

catch (Exception ex)

{

Trace.TraceError("An exception occured " +

"while initializing XPathDocument and XPathNavigator in XPathQueryManager: " +

ex.Message);

throw ex;

}

finally

{

xmlStream.Dispose();

}

}

/// <summary>

/// This method sets the inherent XPathNodeIterator instance.

/// </summary>

/// <param name="xPath">A compiled XPath expression</param>

private void findXPath(XPathExpression xPath)

{

xPath.SetContext(_ParamContext);

_XIter = _XNav.Select(xPath);

InitializeCustomContext(_ParamContext);

}

private void InitializeCustomContext(CustomQueryContext paramContext)

{

IDictionary<string, string> namespaces = paramContext.GetNamespacesInScope(XmlNamespaceScope.ExcludeXml);

_ParamContext = new CustomQueryContext((NameTable) paramContext.NameTable);

_ParamContext.AddNamespace(namespaces);

}

#endregion

#region Nested Types

#region CustomQueryContext

/// <summary>

/// This class represents a custom context for XPath queries.

/// It is derived from XsltContext.

/// </summary>

public class CustomQueryContext : XsltContext

{

#region Fields

private XsltArgumentList _ArgumentList = new XsltArgumentList();

#endregion

#region Constructors

/// <summary>

/// Initializes a new instance of the <see cref="CustomQueryContext"/> class.

/// </summary>

public CustomQueryContext()

{

}

/// <summary>

/// Initializes a new instance of the <see cref="CustomQueryContext"/> class.

/// </summary>

/// <param name="table">A NameTable instance</param>

public CustomQueryContext(NameTable table)

: base(table)

{

}

#endregion

#region Public Member

/// <summary>

/// Method from XsltContext.

/// </summary>

public override bool Whitespace

{

get { return true; }

}

/// <summary>

/// This method adds a list of namespaces to use in the custom context.

/// </summary>

/// <param name="namespaces">A list of namespaces</param>

public void AddNamespace(IDictionary<string, string> namespaces)

{

foreach (string ns in namespaces.Keys)

AddNamespace(ns, namespaces[ns]);

}

/// <summary>

/// Method from XsltContext.

/// </summary>

public override int CompareDocument(string baseUri, string nextbaseUri)

{

return 0;

}

/// <summary>

/// Method from XsltContext.

/// </summary>

public override bool PreserveWhitespace(XPathNavigator node)

{

return true;

}

/// <summary>

/// This method resolves a function appearing in an XPath expression.

/// </summary>

/// <param name="prefix">The prefix of the function</param>

/// <param name="name">The name of the function</param>

/// <param name="ArgTypes">A list of argument types of the function</param>

public override IXsltContextFunction ResolveFunction(string prefix, string name, XPathResultType[] ArgTypes)

{

if (name.Equals(ParamCompare.FunctionName)) return new ParamCompare(ArgTypes, 2, 2);

if (name.Equals(ParamCompareWithTargetNs.FunctionName))

return new ParamCompareWithTargetNs(ArgTypes, 3, 3);

return null;

}

/// <summary>

/// This method resolves a variable appearing in an XPath expression.

/// </summary>

/// <param name="prefix">The prefix of the variable</param>

/// <param name="name">The name of the variable</param>

public override IXsltContextVariable ResolveVariable(string prefix, string name)

{

object param = GetParam(name);

if (param != null)

return new ParamFunctionVar(name, param);

return null;

}

/// <summary>

/// This method adds a parameter to the custom context.

/// </summary>

/// <param name="name">The name of the parameter</param>

/// <param name="parameter">The value of the parameter</param>

public void AddParam(string name, object parameter)

{

_ArgumentList.AddParam(name, string.Empty, parameter);

}

/// <summary>

/// This method adds a list of parameters to the custom context.

/// </summary>

/// <param name="parameters">A list of parameters</param>

public void AddParam(DictionaryEntry[] parameters)

{

int length = parameters.Length;

for (int i = 0; i < length; i++)

_ArgumentList.AddParam(parameters[i].Key.ToString(),

string.Empty, parameters[i].Value.ToString());

}

/// <summary>

/// This method gets a parameter by name.

/// </summary>

/// <param name="name">The name of the parameter</param>

public object GetParam(string name)

{

return _ArgumentList.GetParam(name, string.Empty);

}

/// <summary>

/// This method removes a parameter from the inherent parameter list.

/// </summary>

/// <param name="name">The name of the parameter</param>

public object RemoveParam(string name)

{

return _ArgumentList.RemoveParam(name, string.Empty);

}

/// <summary>

/// This methods clears the inherent parameter list.

/// </summary>

public void ResetParams()

{

_ArgumentList.Clear();

}

#endregion

}

#endregion

#region ParamBase

/// <summary>

/// This class is the base class of <see cref="ParamCompare"/> and <see cref="ParamCompareWithTargetNs"/>.

/// </summary>

public abstract class ParamBase

{

#region Fields

private XPathResultType[] _ArgTypes;

private int _MaxArgs;

private int _MinArgs;

private XPathResultType _ReturnType;

#endregion

#region Properties

/// <summary>

/// Gets the argument types.

/// </summary>

public XPathResultType[] ArgTypes

{

get { return _ArgTypes; }

}

/// <summary>

/// Gets the return type.

/// </summary>

public XPathResultType ReturnType

{

get { return _ReturnType; }

}

/// <summary>

/// Gets the minimum number of arguments allowed.

/// </summary>

public int Minargs

{

get { return _MinArgs; }

}

/// <summary>

/// Gets the maximum number of arguments allowed.

/// </summary>

public int Maxargs

{

get { return _MaxArgs; }

}

#endregion

#region Constructors

/// <summary>

/// Protected constructor for the abstract class.

/// </summary>

/// <param name="argTypes">The argument types of the function</param>

/// <param name="returnType">The return type of the function</param>

/// <param name="minArgs">The minimum number of arguments allowed</param>

/// <param name="maxArgs">The maximum number of arguments allowed</param>

protected ParamBase(XPathResultType[] argTypes, XPathResultType returnType,

int minArgs, int maxArgs)

{

_ArgTypes = argTypes;

_ReturnType = returnType;

_MinArgs = minArgs;

_MaxArgs = maxArgs;

}

#endregion

}

#endregion

#region ParamCompare

/// <summary>

/// This class performs a string comparison in an XPath expression.

/// </summary>

public class ParamCompare : ParamBase, IXsltContextFunction

{

#region Fields

/// <summary>

/// The name to use when embedding the function in an XPath expression.

/// </summary>

public static readonly string FunctionName = "_PARAMCOMP_";

#endregion

#region Constructors

/// <summary>

/// Initializes a new instance of the <see cref="ParamCompare"/> class.

/// </summary>

/// <param name="argTypes">The argument types of the function</param>

/// <param name="minArgs">The minimum number of arguments allowed</param>

/// <param name="maxArgs">The maximum number of arguments allowed</param>

public ParamCompare(XPathResultType[] argTypes, int minArgs, int maxArgs)

: base(argTypes, XPathResultType.Boolean, minArgs, maxArgs)

{

}

#endregion

#region IXsltContextFunction Member

/// <summary>

/// This method performs a string comparison.

/// </summary>

/// <param name="xsltContext">The Xslt context</param>

/// <param name="args">The arguments of the function</param>

/// <param name="docContext">The document context</param>

/// <returns>A boolean value indicating whether the argument strings are identical</returns>

public virtual object Invoke(XsltContext xsltContext, object[] args, XPathNavigator docContext)

{

return resolveNsPrefix(ResolveArgument(args[0]), xsltContext).Equals(

resolveNsPrefix(ResolveArgument(args[1]), xsltContext), StringComparison.Ordinal);

}

#endregion

#region Protected Member

/// <summary>

/// This method creates a string from an object argument.

/// In many cases the argument is an XPathNodeIterator that must be resolved.

/// </summary>

/// <param name="arg">An argument of the function to be resolved</param>

protected string ResolveArgument(object arg)

{

if (arg is string)

return arg.ToString();

else if (arg is XPathNodeIterator)

if (((XPathNodeIterator) arg).MoveNext() == true)

return ((XPathNodeIterator) arg).Current.Value;

return string.Empty;

}

#endregion

#region Private Member

/// <summary>

/// This method resolves the prefix of an argument.

/// If a prefix is found, the corresponding namespace URI is looked up

/// and substituted.

/// </summary>

/// <param name="args">An argument of the function to be resolved</param>

/// <param name="xsltContext">The Xslt context for namespace resolving</param>

private string resolveNsPrefix(string args, XsltContext xsltContext)

{

string prefix;

string ns;

if (args.Contains(":"))

{

prefix = args.Substring(0, args.IndexOf(":"));

if (!string.IsNullOrEmpty((ns = xsltContext.LookupNamespace(prefix))))

args = args.Replace(prefix + ":", ns);

}

return args;

}

#endregion

}

#endregion

#region ParamCompareWithTargetNs

/// <summary>

/// This class performs a string comparison in an XPath expression.

/// It is specifically created for using in XML schema documents.

/// </summary>

public class ParamCompareWithTargetNs : ParamCompare

{

#region Fields

/// <summary>

/// The name to use when embedding the function in an XPath expression.

/// </summary>

public static new readonly string FunctionName = "_PARAMCOMPWITHTARGETNS_";

#endregion

#region Constructors

/// <summary>

/// Initializes a new instance of the <see cref="ParamCompareWithTargetNs"/> class.

/// </summary>

/// <param name="argTypes">The argument types of the function</param>

/// <param name="minArgs">The minimum number of arguments allowed</param>

/// <param name="maxArgs">The maximum number of arguments allowed</param>

public ParamCompareWithTargetNs(XPathResultType[] argTypes, int minArgs, int maxArgs)

: base(argTypes, minArgs, maxArgs)

{

}

#endregion

#region IXsltContextFunction Member

/// <summary>

/// This method performs a string comparison.

/// </summary>

/// <param name="xsltContext">The Xslt context</param>

/// <param name="args">The arguments of the function</param>

/// <param name="docContext">The document context</param>

/// <returns>A boolean value indicating whether the argument strings are identical</returns>

public override object Invoke(XsltContext xsltContext, object[] args, XPathNavigator docContext)

{

return ((string) ((string) args[1] + ResolveArgument(args[2]))).Equals(

ResolveNsPrefix(ResolveArgument(args[0]), (string) args[1], docContext), StringComparison.Ordinal);

}

#endregion

#region Private Member

/// <summary>

/// This method resolves the prefix of an argument.

/// If a prefix is found, the corresponding namespace URI (if existing) is looked up

/// and substituted. Otherwise the target namespace is placed first.

/// </summary>

/// <param name="args">An argument of the function to be resolved</param>

/// <param name="targetNs">The target namespace</param>

/// <param name="docContext">The document context</param>

private static string ResolveNsPrefix(string args, string targetNs, XPathNavigator docContext)

{

if (args.Contains(":"))

{

var prefix = args.Substring(0, args.IndexOf(":", StringComparison.Ordinal));

string ns;

if (!string.IsNullOrEmpty((ns = docContext.LookupNamespace(prefix))))

return args.Replace(prefix + ":", ns);

return targetNs + args;

}

return targetNs + args;

}

#endregion

}

#endregion

#region ParamFunctionVar

/// <summary>

/// This class represents a variable in an XPath expression.

/// </summary>

public class ParamFunctionVar : IXsltContextVariable

{

#region Fields

private string _Name;

private object _Param;

#endregion

#region Constructors

/// <summary>

/// Initializes a new instance of the <see cref="ParamFunctionVar"/> class.

/// </summary>

/// <param name="name">The name of the variable</param>

/// <param name="param">The parameter</param>

public ParamFunctionVar(string name, object param)

{

_Name = name;

_Param = param;

}

#endregion

#region IXsltContextVariable Member

/// <summary>

/// Method implementing IXsltContextVariable

/// </summary>

public object Evaluate(XsltContext xsltContext)

{

return _Param;

}

/// <summary>

/// Method implementing IXsltContextVariable

/// </summary>

public bool IsLocal

{

get { return true; }

}

/// <summary>

/// Method implementing IXsltContextVariable

/// </summary>

public bool IsParam

{

get { return true; }

}

/// <summary>

/// Method implementing IXsltContextVariable

/// </summary>

public XPathResultType VariableType

{

get { return XPathResultType.Any; }

}

#endregion

}

#endregion

#endregion

}

}