protected override IReadOnlyCollection <ResourceFieldAttribute> OnResolveFieldChain(string path, FieldChainRequirements chainRequirements)
{
if (chainRequirements == FieldChainRequirements.EndsInToMany)
{
return(ChainResolver.ResolveToOneChainEndingInToMany(_resourceContextInScope, path, _validateSingleFieldCallback));
}
if (chainRequirements == FieldChainRequirements.EndsInAttribute)
{
return(ChainResolver.ResolveToOneChainEndingInAttribute(_resourceContextInScope, path, _validateSingleFieldCallback));
}
if (chainRequirements.HasFlag(FieldChainRequirements.EndsInAttribute) && chainRequirements.HasFlag(FieldChainRequirements.EndsInToOne))
{
return(ChainResolver.ResolveToOneChainEndingInAttributeOrToOne(_resourceContextInScope, path, _validateSingleFieldCallback));
}
throw new InvalidOperationException($"Unexpected combination of chain requirement flags '{chainRequirements}'.");
}
protected ComparisonExpression ParseComparison(string operatorName)
{
var comparisonOperator = Enum.Parse <ComparisonOperator>(operatorName.Pascalize());
EatText(operatorName);
EatSingleCharacterToken(TokenKind.OpenParen);
// Allow equality comparison of a HasOne relationship with null.
FieldChainRequirements leftChainRequirements = comparisonOperator == ComparisonOperator.Equals
? FieldChainRequirements.EndsInAttribute | FieldChainRequirements.EndsInToOne
: FieldChainRequirements.EndsInAttribute;
QueryExpression leftTerm = ParseCountOrField(leftChainRequirements);
EatSingleCharacterToken(TokenKind.Comma);
QueryExpression rightTerm = ParseCountOrConstantOrNullOrField(FieldChainRequirements.EndsInAttribute);
EatSingleCharacterToken(TokenKind.CloseParen);
if (leftTerm is ResourceFieldChainExpression leftChain)
{
if (leftChainRequirements.HasFlag(FieldChainRequirements.EndsInToOne) && !(rightTerm is NullConstantExpression))
{
// Run another pass over left chain to have it fail when chain ends in relationship.
OnResolveFieldChain(leftChain.ToString(), FieldChainRequirements.EndsInAttribute);
}
PropertyInfo leftProperty = leftChain.Fields.Last().Property;
if (leftProperty.Name == nameof(Identifiable.Id) && rightTerm is LiteralConstantExpression rightConstant)
{
string id = DeObfuscateStringId(leftProperty.ReflectedType, rightConstant.Value);
rightTerm = new LiteralConstantExpression(id);
}
}
return(new ComparisonExpression(comparisonOperator, leftTerm, rightTerm));
}
