/// <summary>
/// Search for the attribute in the context target item using the attribute designator specified.
/// </summary>
/// <param name="context">The evaluation context instance.</param>
/// <param name="attributeDesignator">The attribute designator instance.</param>
/// <param name="targetItem">The target item to search in.</param>
/// <returns>A bag value with the values of the attributes found.</returns>
public static BagValue FindAttribute(EvaluationContext context, pol.AttributeDesignatorBase attributeDesignator, ctx.TargetItemBase targetItem)
{
var bag = new BagValue(GetDataType(attributeDesignator.DataType));
foreach (ctx.AttributeElement attribute in targetItem.Attributes)
{
if (attribute.Match(attributeDesignator))
{
context.Trace("Adding target item attribute designator: {0}", attribute.ToString());
bag.Add(attribute);
}
}
return bag;
}
/// <summary>
/// Solves the attribute designator in the context document using the attribute designator type
/// </summary>
/// <param name="context">The evaluation context instance.</param>
/// <param name="attributeDesignator">The attribute designator to resolve</param>
/// <returns>A bag value with the values found in the context document</returns>
public static BagValue Resolve(EvaluationContext context, pol.AttributeDesignatorBase attributeDesignator)
{
if (attributeDesignator is SubjectAttributeDesignatorElement)
{
if (context.ContextDocument.Request != null && context.ContextDocument.Request.Subjects != null)
{
var bag = new BagValue(GetDataType(attributeDesignator.DataType));
foreach (ctx.SubjectElement subject in context.ContextDocument.Request.Subjects)
{
if (((SubjectAttributeDesignatorElement)attributeDesignator).SubjectCategory == null ||
((SubjectAttributeDesignatorElement)attributeDesignator).SubjectCategory == subject.SubjectCategory)
{
foreach (ctx.AttributeElement attrib in FindAttribute(context, attributeDesignator, subject).Elements)
{
bag.Add(attrib);
}
}
}
return bag;
}
}
else if (attributeDesignator is ResourceAttributeDesignatorElement)
{
if (context.ContextDocument.Request != null && context.CurrentResource != null)
{
return FindAttribute(context, attributeDesignator, context.CurrentResource);
}
else
{
return BagValue.Empty;
}
}
else if (attributeDesignator is ActionAttributeDesignatorElement)
{
if (context.ContextDocument.Request != null && context.ContextDocument.Request.Action != null)
{
return FindAttribute(context, attributeDesignator, context.ContextDocument.Request.Action);
}
else
{
return BagValue.Empty;
}
}
else if (attributeDesignator is EnvironmentAttributeDesignatorElement)
{
if (context.ContextDocument.Request != null && context.ContextDocument.Request.Environment != null)
{
return FindAttribute(context, attributeDesignator, context.ContextDocument.Request.Environment);
}
else
{
return BagValue.Empty;
}
}
throw new EvaluationException(Properties.Resource.exc_invalid_attribute_designator);
}
/// <summary>
/// THe argument processing method resolves all the attribute designators, attribute
/// selectors. If there is an internal Apply it will be evaulated within this method.
/// </summary>
/// <remarks>All the processed arguments are converted into an IFunctionParameter instance
/// because this is the only value that can be used to call a function.</remarks>
/// <param name="context">The evaluation context instance.</param>
/// <param name="arguments">The arguments to process.</param>
/// <returns>A list of arguments ready to be used by a function.</returns>
private FunctionParameterCollection ProcessArguments(EvaluationContext context, ExpressionCollection arguments)
{
context.Trace("Processing arguments");
context.AddIndent();
// Create a list to return the processed values.
var processedArguments = new FunctionParameterCollection();
// Iterate through the arguments, the IExpressionType is a mark interface
foreach (IExpression arg in arguments)
{
var apply = arg as ApplyElement;
if (apply != null)
{
context.Trace("Nested apply");
// There is a nested apply un this policy a new Apply will be created and also
// evaluated. It's return value will be used as the processed argument.
var childApply = new Apply(apply);
// Evaluate the Apply
EvaluationValue retVal = childApply.Evaluate(context);
context.TraceContextValues();
// If the results were Indeterminate the Indeterminate value will be placed in
// the processed arguments, later another method will validate the parameters
// and cancel the evaluation propperly.
if (!retVal.IsIndeterminate)
{
if (!context.IsMissingAttribute)
{
processedArguments.Add(retVal);
}
}
else
{
processedArguments.Add(retVal);
}
}
else
{
var write = arg as FunctionElementReadWrite;
if (write != null)
{
// Search for the function and place it in the processed arguments.
var functionId = new FunctionElement(write.FunctionId, write.SchemaVersion);
context.Trace("Function {0}", functionId.FunctionId);
IFunction function = EvaluationEngine.GetFunction(functionId.FunctionId);
if (function == null)
{
context.Trace("ERR: function not found {0}", _applyBase.FunctionId);
context.ProcessingError = true;
processedArguments.Add(EvaluationValue.Indeterminate);
}
else
{
processedArguments.Add(function);
}
}
else if (arg is VariableReferenceElement)
{
var variableRef = arg as VariableReferenceElement;
var variableDef = context.CurrentPolicy.VariableDefinition[variableRef.VariableId] as VariableDefinition;
context.TraceContextValues();
Debug.Assert(variableDef != null, "variableDef != null");
processedArguments.Add(!variableDef.IsEvaluated ? variableDef.Evaluate(context) : variableDef.Value);
}
else
{
var readWrite = arg as AttributeValueElementReadWrite;
if (readWrite != null)
{
// The AttributeValue does not need to be processed
context.Trace("Attribute value {0}", arg.ToString());
processedArguments.Add(new AttributeValueElement(readWrite.DataType, readWrite.Contents, readWrite.SchemaVersion));
}
else
{
var des = arg as AttributeDesignatorBase;
if (des != null)
{
// Resolve the AttributeDesignator using the EvaluationEngine public methods.
context.Trace("Processing attribute designator: {0}", arg.ToString());
var attrDes = des;
BagValue bag = EvaluationEngine.Resolve(context, attrDes);
// If the attribute was not resolved by the EvaluationEngine search the
// attribute in the context document, also using the EvaluationEngine public
// methods.
if (bag.BagSize == 0)
{
if (arg is SubjectAttributeDesignatorElement)
{
ctx.AttributeElement attrib = EvaluationEngine.GetAttribute(context, attrDes);
if (attrib != null)
{
context.Trace("Adding subject attribute designator: {0}", attrib.ToString());
bag.Add(attrib);
break;
}
}
else if (arg is ResourceAttributeDesignatorElement)
{
ctx.AttributeElement attrib = EvaluationEngine.GetAttribute(context, attrDes);
if (attrib != null)
{
context.Trace("Adding resource attribute designator {0}", attrib.ToString());
bag.Add(attrib);
}
}
else if (arg is ActionAttributeDesignatorElement)
{
ctx.AttributeElement attrib = EvaluationEngine.GetAttribute(context, attrDes);
if (attrib != null)
{
context.Trace("Adding action attribute designator {0}", attrib.ToString());
bag.Add(attrib);
}
}
else if (arg is EnvironmentAttributeDesignatorElement)
{
ctx.AttributeElement attrib = EvaluationEngine.GetAttribute(context, attrDes);
if (attrib != null)
{
context.Trace("Adding environment attribute designator {0}", attrib.ToString());
bag.Add(attrib);
}
}
}
// If the argument was not found and the attribute must be present this is
// a MissingAttribute situation so set the flag. Otherwise add the attribute
// to the processed arguments.
if (bag.BagSize == 0 && attrDes.MustBePresent)
{
context.Trace("Attribute is missing");
context.IsMissingAttribute = true;
context.AddMissingAttribute(attrDes);
}
else
{
processedArguments.Add(bag);
}
}
else
{
var @base = arg as AttributeSelectorElement;
if (@base != null)
{
// Resolve the XPath query using the EvaluationEngine public methods.
context.Trace("Attribute selector");
try
{
BagValue bag = EvaluationEngine.Resolve(context, @base);
if (bag.Elements.Count == 0 && @base.MustBePresent)
{
context.Trace("Attribute is missing");
context.IsMissingAttribute = true;
context.AddMissingAttribute(@base);
}
else
{
processedArguments.Add(bag);
}
}
catch (EvaluationException e)
{
context.Trace("ERR: {0}", e.Message);
processedArguments.Add(EvaluationValue.Indeterminate);
context.ProcessingError = true;
}
}
}
}
}
}
}
context.RemoveIndent();
return(processedArguments);
}
/// <summary>
/// Resolves the AttributeSelector in the context document using the XPath sentence.
/// </summary>
/// <param name="context">The evaluation context instance.</param>
/// <param name="attributeSelector">The attribute selector.</param>
/// <returns>A bag of values with the contents of the node.</returns>
public static BagValue Resolve(EvaluationContext context, pol.AttributeSelectorElement attributeSelector)
{
var bagValue = new BagValue(GetDataType(attributeSelector.DataType));
var content = (ctx.ResourceContentElement)context.CurrentResource.ResourceContent;
if (content != null)
{
XmlDocument doc = context.ContextDocument.XmlDocument;
if (context.ContextDocument.XmlNamespaceManager == null)
{
context.ContextDocument.AddNamespaces(context.PolicyDocument.Namespaces);
}
try
{
string xpath = attributeSelector.RequestContextPath;
Debug.Assert(doc.DocumentElement != null, "doc.DocumentElement != null");
XmlNodeList nodeList = doc.DocumentElement.SelectNodes(xpath, context.ContextDocument.XmlNamespaceManager);
if (nodeList != null)
{
foreach (XmlNode node in nodeList)
{
var ave =
new pol.AttributeValueElement(
attributeSelector.DataType,
node.InnerText,
attributeSelector.SchemaVersion);
bagValue.Add(ave);
}
}
}
catch (XPathException e)
{
context.Trace("ERR: {0}", e.Message);
bagValue = new BagValue(GetDataType(attributeSelector.DataType));
}
}
return bagValue;
}
/// <summary>
/// Evaluates the variable into a value.
/// </summary>
/// <param name="context">The contex of the evaluation.</param>
/// <returns>The value of the function.</returns>
public EvaluationValue Evaluate(EvaluationContext context)
{
if (context == null)
{
throw new ArgumentNullException("context");
}
context.Trace("Evaluating variable");
context.AddIndent();
try
{
if (_variableDefinition.Expression is ApplyElement)
{
context.Trace("Apply within condition.");
// There is a nested apply un this policy a new Apply will be created and also
// evaluated. It's return value will be used as the processed argument.
Apply childApply = new Apply((ApplyElement)_variableDefinition.Expression);
// Evaluate the Apply
_value = childApply.Evaluate(context);
context.TraceContextValues();
return(_value);
}
else if (_variableDefinition.Expression is FunctionElement)
{
throw new NotImplementedException("FunctionElement"); //TODO:
}
else if (_variableDefinition.Expression is VariableReferenceElement)
{
var variableRef = _variableDefinition.Expression as VariableReferenceElement;
var variableDef = context.CurrentPolicy.VariableDefinition[variableRef.VariableId] as VariableDefinition;
context.TraceContextValues();
if (!variableDef.IsEvaluated)
{
return(variableDef.Evaluate(context));
}
else
{
return(variableDef.Value);
}
}
else if (_variableDefinition.Expression is AttributeValueElementReadWrite)
{
// The AttributeValue does not need to be processed
context.Trace("Attribute value {0}", _variableDefinition.Expression.ToString());
var att = (AttributeValueElementReadWrite)_variableDefinition.Expression;
var attributeValue = new AttributeValueElement(att.DataType, att.Contents, att.SchemaVersion);
_value = new EvaluationValue(
attributeValue.GetTypedValue(attributeValue.GetType(context), 0),
attributeValue.GetType(context));
return(_value);
}
else if (_variableDefinition.Expression is AttributeDesignatorBase)
{
// Resolve the AttributeDesignator using the EvaluationEngine public methods.
context.Trace("Processing attribute designator: {0}", _variableDefinition.Expression.ToString());
var attrDes = (AttributeDesignatorBase)_variableDefinition.Expression;
BagValue bag = EvaluationEngine.Resolve(context, attrDes);
// If the attribute was not resolved by the EvaluationEngine search the
// attribute in the context document, also using the EvaluationEngine public
// methods.
if (bag.BagSize == 0)
{
if (_variableDefinition.Expression is SubjectAttributeDesignatorElement)
{
ctx.AttributeElement attrib = EvaluationEngine.GetAttribute(context, attrDes);
if (attrib != null)
{
context.Trace("Adding subject attribute designator: {0}", attrib.ToString());
bag.Add(attrib);
}
}
else if (_variableDefinition.Expression is ResourceAttributeDesignatorElement)
{
ctx.AttributeElement attrib = EvaluationEngine.GetAttribute(context, attrDes);
if (attrib != null)
{
context.Trace("Adding resource attribute designator {0}", attrib.ToString());
bag.Add(attrib);
}
}
else if (_variableDefinition.Expression is ActionAttributeDesignatorElement)
{
ctx.AttributeElement attrib = EvaluationEngine.GetAttribute(context, attrDes);
if (attrib != null)
{
context.Trace("Adding action attribute designator {0}", attrib.ToString());
bag.Add(attrib);
}
}
else if (_variableDefinition.Expression is EnvironmentAttributeDesignatorElement)
{
ctx.AttributeElement attrib = EvaluationEngine.GetAttribute(context, attrDes);
if (attrib != null)
{
context.Trace("Adding environment attribute designator {0}", attrib.ToString());
bag.Add(attrib);
}
}
}
// If the argument was not found and the attribute must be present this is
// a MissingAttribute situation so set the flag. Otherwise add the attribute
// to the processed arguments.
if (bag.BagSize == 0 && attrDes.MustBePresent)
{
context.Trace("Attribute is missing");
context.IsMissingAttribute = true;
context.AddMissingAttribute(attrDes);
_value = EvaluationValue.Indeterminate;
}
else
{
_value = new EvaluationValue(bag, bag.GetType(context));
}
return(_value);
}
else if (_variableDefinition.Expression is AttributeSelectorElement)
{
// Resolve the XPath query using the EvaluationEngine public methods.
context.Trace("Attribute selector");
try
{
var attributeSelector = (AttributeSelectorElement)_variableDefinition.Expression;
BagValue bag = EvaluationEngine.Resolve(context, attributeSelector);
if (bag.Elements.Count == 0 && attributeSelector.MustBePresent)
{
context.Trace("Attribute is missing");
context.IsMissingAttribute = true;
context.AddMissingAttribute(attributeSelector);
_value = EvaluationValue.Indeterminate;
}
else
{
_value = new EvaluationValue(bag, bag.GetType(context));
}
}
catch (EvaluationException e)
{
context.Trace("ERR: {0}", e.Message);
context.ProcessingError = true;
_value = EvaluationValue.Indeterminate;
}
return(_value);
}
throw new NotSupportedException("internal error");
}
finally
{
_isEvaluated = true;
context.RemoveIndent();
}
}