/*
* useCurrentInstanceVariable is probably always false in the current version of the algorithm.
*/
public XPathExpr GetRelativeXPath(PSMComponent node, bool useCurrentInstanceVariable, string currentInstanceVariableName = XDocumentXsltExtensions.ParamCurrentInstance)
{
PSMComponent closestExistingCurrentNode = CurrentNode.GetFirstAncestorOrSelfExistingInVersion(OldVersion).GetInVersion(OldVersion);
PSMComponent closestExistingTargetNode = node.GetFirstAncestorOrSelfExistingInVersion(OldVersion).GetInVersion(OldVersion);
if (closestExistingTargetNode == null)
{
throw new InvalidOperationException();
}
if (closestExistingCurrentNode == null)
{
return(new XPathExpr(closestExistingTargetNode.XPath));
}
XPathExpr currentNodeAbsoluteXPath = new XPathExpr(closestExistingCurrentNode.GetInVersion(OldVersion).XPath);
// /A/R
XPathExpr targetNodeAbsoluteXPath = new XPathExpr(closestExistingTargetNode.GetInVersion(OldVersion).XPath);
// /A/R/B/z
if (targetNodeAbsoluteXPath.HasPrefix(currentNodeAbsoluteXPath) && targetNodeAbsoluteXPath != currentNodeAbsoluteXPath)
{
string withoutPrefix = targetNodeAbsoluteXPath.ToString().Substring(currentNodeAbsoluteXPath.ToString().Length);
while (withoutPrefix[0].IsAmong('/', '@'))
{
withoutPrefix = withoutPrefix.Substring(1);
}
string nextStep;
if (withoutPrefix.IndexOf('/') == -1)
{
nextStep = withoutPrefix.Substring(0, withoutPrefix.Length);
}
else
{
nextStep = withoutPrefix.Substring(0, withoutPrefix.IndexOf('/'));
}
string afterNextStep = withoutPrefix.Substring(nextStep.Length);
XPathExpr result;
if (useCurrentInstanceVariable)
{
result = new XPathExpr(string.Format("${3}[name() = '{0}']{1}{2}", nextStep, string.IsNullOrEmpty(afterNextStep) ? string.Empty : "/", afterNextStep, currentInstanceVariableName));
}
else
{
result = new XPathExpr(string.Format("{0}{1}{2}", nextStep, string.IsNullOrEmpty(afterNextStep) ? string.Empty : "/", afterNextStep));
}
return(result);
}
else if (targetNodeAbsoluteXPath == currentNodeAbsoluteXPath)
{
return(new XPathExpr("."));
}
else
{
// find the uppermost common node
PSMAssociationMember nearestCommonAncestor = closestExistingCurrentNode.GetNearestCommonAncestor(closestExistingTargetNode);
if (nearestCommonAncestor != null)
{
string commonPath = nearestCommonAncestor.XPath;
Debug.Assert(targetNodeAbsoluteXPath.HasPrefix(new XPathExpr(commonPath)));
Debug.Assert(currentNodeAbsoluteXPath.HasPrefix(new XPathExpr(commonPath)));
string fromCommonToTarget = targetNodeAbsoluteXPath.ToString().Replace(commonPath, string.Empty);
string fromCommonToCurrent = currentNodeAbsoluteXPath.ToString().Replace(commonPath, string.Empty);
string stepsUp = string.Empty;
foreach (char c in fromCommonToCurrent)
{
if (c == '/')
{
stepsUp += "../";
}
}
if (fromCommonToTarget.StartsWith("/"))
{
fromCommonToTarget = fromCommonToTarget.Substring(1);
}
string joined = string.Format("{0}{1}", stepsUp, fromCommonToTarget);
if (joined.EndsWith("/"))
{
joined = joined.Substring(0, joined.Length - 1);
}
return(new XPathExpr(joined));
}
else
{
return(new XPathExpr(closestExistingTargetNode.XPath));
}
}
}
