/// <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 pol.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((pol.ApplyElement)_variableDefinition.Expression);
// Evaluate the Apply
_value = _childApply.Evaluate(context);
context.TraceContextValues();
return(_value);
}
else if (_variableDefinition.Expression is pol.FunctionElement)
{
throw new NotImplementedException("FunctionElement"); //TODO:
}
else if (_variableDefinition.Expression is pol.VariableReferenceElement)
{
pol.VariableReferenceElement variableRef = _variableDefinition.Expression as pol.VariableReferenceElement;
VariableDefinition 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 pol.AttributeValueElementReadWrite)
{
// The AttributeValue does not need to be processed
context.Trace("Attribute value {0}", _variableDefinition.Expression.ToString());
pol.AttributeValueElementReadWrite att = (pol.AttributeValueElementReadWrite)_variableDefinition.Expression;
pol.AttributeValueElement attributeValue = new pol.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 pol.AttributeDesignatorBase)
{
// Resolve the AttributeDesignator using the EvaluationEngine public methods.
context.Trace("Processing attribute designator: {0}", _variableDefinition.Expression.ToString());
pol.AttributeDesignatorBase attrDes = (pol.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 pol.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 pol.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 pol.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 pol.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 pol.AttributeSelectorElement)
{
// Resolve the XPath query using the EvaluationEngine public methods.
context.Trace("Attribute selector");
try
{
pol.AttributeSelectorElement attributeSelector = (pol.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();
}
}
/// <summary>
/// Resolves the attribute reference defined within the given match.
/// </summary>
/// <param name="context">The evaluation context instance.</param>
/// <param name="match">The target item match.</param>
/// <param name="contextTargetItem">The context target item.</param>
/// <returns>The context attribute.</returns>
public static ctx.AttributeElement Resolve( EvaluationContext context, pol.TargetMatchBaseReadWrite match, ctx.TargetItemBase contextTargetItem )
{
ctx.AttributeElementReadWrite attribute = null;
if( match.AttributeReference is pol.AttributeDesignatorBase )
{
pol.AttributeDesignatorBase attrDesig = (pol.AttributeDesignatorBase)match.AttributeReference;
context.Trace( "Looking for attribute: {0}", attrDesig.AttributeId );
foreach( ctx.AttributeElementReadWrite tempAttribute in contextTargetItem.Attributes )
{
if( tempAttribute.Match( attrDesig ) )
{
attribute = tempAttribute;
break;
}
}
if( attribute == null )
{
context.Trace( "Attribute not found, loading searching an external repository" );
attribute = GetAttribute( context, attrDesig );
}
}
else if( match.AttributeReference is pol.AttributeSelectorElement )
{
pol.AttributeSelectorElement attrSelec = (pol.AttributeSelectorElement)match.AttributeReference;
ctx.ResourceContentElement content = (ctx.ResourceContentElement)((ctx.ResourceElement)contextTargetItem).ResourceContent;
if( content != null )
{
XmlDocument doc = context.ContextDocument.XmlDocument;
if( context.ContextDocument.XmlNamespaceManager == null )
{
context.ContextDocument.AddNamespaces( context.PolicyDocument.Namespaces );
}
string xpath = attrSelec.RequestContextPath;
try
{
XmlNode node = doc.DocumentElement.SelectSingleNode( xpath, context.ContextDocument.XmlNamespaceManager );
if( node != null )
{
attribute = new ctx.AttributeElement( null, attrSelec.DataType, null, null, node.InnerText, attrSelec.SchemaVersion );
}
}
catch( XPathException e )
{
context.Trace( Resource.TRACE_ERROR, e.Message );
context.ProcessingError = true;
}
}
}
if( attribute == null && match.AttributeReference.MustBePresent )
{
context.IsMissingAttribute = true;
context.AddMissingAttribute( match.AttributeReference );
}
if( attribute != null )
{
return new ctx.AttributeElement( attribute.AttributeId, attribute.DataType, attribute.Issuer, attribute.IssueInstant,
attribute.Value, attribute.SchemaVersion);
}
return null;
}
/// <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 IFunctionParameterCollection ProcessArguments(EvaluationContext context, pol.IExpressionCollection arguments)
{
context.Trace("Processing arguments");
context.AddIndent();
// Create a list to return the processed values.
IFunctionParameterCollection processedArguments = new IFunctionParameterCollection();
// Iterate through the arguments, the IExpressionType is a mark interface
foreach (inf.IExpression arg in arguments)
{
if (arg is pol.ApplyElement)
{
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.
Apply _childApply = new Apply((pol.ApplyElement)arg);
// 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 if (arg is pol.FunctionElementReadWrite)
{
// Search for the function and place it in the processed arguments.
pol.FunctionElement functionId = new pol.FunctionElement(((pol.FunctionElementReadWrite)arg).FunctionId, ((pol.FunctionElementReadWrite)arg).SchemaVersion);
context.Trace("Function {0}", functionId.FunctionId);
inf.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 pol.VariableReferenceElement)
{
pol.VariableReferenceElement variableRef = arg as pol.VariableReferenceElement;
VariableDefinition variableDef = context.CurrentPolicy.VariableDefinition[variableRef.VariableId] as VariableDefinition;
context.TraceContextValues();
if (!variableDef.IsEvaluated)
{
processedArguments.Add(variableDef.Evaluate(context));
}
else
{
processedArguments.Add(variableDef.Value);
}
}
else if (arg is pol.AttributeValueElementReadWrite)
{
// The AttributeValue does not need to be processed
context.Trace("Attribute value {0}", arg.ToString());
processedArguments.Add(new pol.AttributeValueElement(((pol.AttributeValueElementReadWrite)arg).DataType, ((pol.AttributeValueElementReadWrite)arg).Contents, ((pol.AttributeValueElementReadWrite)arg).SchemaVersion));
}
else if (arg is pol.AttributeDesignatorBase)
{
// Resolve the AttributeDesignator using the EvaluationEngine public methods.
context.Trace("Processing attribute designator: {0}", arg.ToString());
pol.AttributeDesignatorBase attrDes = (pol.AttributeDesignatorBase)arg;
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 pol.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 pol.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 pol.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 pol.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 if (arg is pol.AttributeSelectorElement)
{
// Resolve the XPath query using the EvaluationEngine public methods.
context.Trace("Attribute selector");
try
{
BagValue bag = EvaluationEngine.Resolve(context, (pol.AttributeSelectorElement)arg);
if (bag.Elements.Count == 0 && ((pol.AttributeSelectorElement)arg).MustBePresent)
{
context.Trace("Attribute is missing");
context.IsMissingAttribute = true;
context.AddMissingAttribute((pol.AttributeReferenceBase)arg);
}
else
{
processedArguments.Add(bag);
}
}
catch (EvaluationException e)
{
context.Trace(Resource.TRACE_ERROR, e.Message);
processedArguments.Add(EvaluationValue.Indeterminate);
context.ProcessingError = true;
}
}
}
context.RemoveIndent();
return(processedArguments);
}
/// <summary>
/// Clones an Attribute from another attribute.
/// </summary>
/// <param name="attributeElement">The attribute id.</param>
public AttributeElement( AttributeElement attributeElement )
: base( attributeElement )
{
}
/// <summary>
/// Clones an Attribute from another attribute.
/// </summary>
/// <param name="attributeElement">The attribute id.</param>
public AttributeElement(AttributeElement attributeElement)
: base(attributeElement)
{
}
/// <summary>
/// Evaluates the target items and return wether the target applies to the context or not.
/// </summary>
/// <param name="context">The evaluation context instance.</param>
/// <param name="targetItem">The target item in the context document.</param>
/// <returns></returns>
public TargetEvaluationValue Evaluate(EvaluationContext context, ctx.TargetItemBase targetItem)
{
if (context == null)
{
throw new ArgumentNullException(nameof(context));
}
if (_targetItems.IsAny)
{
context.Trace("IsAny");
return(TargetEvaluationValue.Match);
}
_evaluationValue = TargetEvaluationValue.NoMatch;
//Match TargetItem
foreach (pol.TargetItemBase polItem in _targetItems.ItemsList)
{
foreach (pol.TargetMatchBase match in polItem.Match)
{
_evaluationValue = TargetEvaluationValue.NoMatch;
context.Trace("Using function: {0}", match.MatchId);
inf.IFunction matchFunction = EvaluationEngine.GetFunction(match.MatchId);
if (matchFunction == null)
{
context.Trace("ERR: function not found {0}", match.MatchId);
context.ProcessingError = true;
return(TargetEvaluationValue.Indeterminate);
}
if (matchFunction.Returns == null)
{
// Validates the function return value
context.Trace("ERR: The function '{0}' does not defines it's return value", match.MatchId);
context.ProcessingError = true;
return(TargetEvaluationValue.Indeterminate);
}
if (matchFunction.Returns != DataTypeDescriptor.Boolean)
{
context.Trace("ERR: Function does not return Boolean a value");
context.ProcessingError = true;
return(TargetEvaluationValue.Indeterminate);
}
ctx.AttributeElement attribute = EvaluationEngine.Resolve(context, match, targetItem);
if (attribute != null)
{
context.Trace("Attribute found, evaluating match function");
try
{
EvaluationValue returnValue = EvaluationEngine.EvaluateFunction(context, matchFunction, match.AttributeValue, attribute);
_evaluationValue = returnValue.BoolValue ? TargetEvaluationValue.Match : TargetEvaluationValue.NoMatch;
}
catch (EvaluationException e)
{
context.Trace(Resource.TRACE_ERROR, e.Message);
_evaluationValue = TargetEvaluationValue.Indeterminate;
}
}
// Validate MustBePresent
if (match.AttributeReference.MustBePresent)
{
if (context.IsMissingAttribute)
{
context.Trace("Attribute not found and must be present");
_evaluationValue = TargetEvaluationValue.Indeterminate;
}
}
// Do not iterate if the value was found
if (_evaluationValue != TargetEvaluationValue.Match)
{
break;
}
}
// Do not iterate if the value was found
if (_evaluationValue == TargetEvaluationValue.Match)
{
return(_evaluationValue);
}
}
return(_evaluationValue);
}
