/// <summary>
/// Determines whether the supplied <see cref="BinaryExpression"/> is convertible to a binary in the context of the featureset of
/// the Rebel Framework-supported expression tree.
/// </summary>
/// <param name="expression">The expression.</param>
/// <param name="structureBinder">The structure binder.</param>
/// <returns><c>true</c> if [is convertible binary] [the specified expression]; otherwise, <c>false</c>.</returns>
/// <remarks></remarks>
public static bool IsConvertibleBinary(BinaryExpression expression, AbstractQueryStructureBinder structureBinder)
{
var left = expression.Left;
var right = expression.Right;
BindingSignatureSupport bindingSignatureSupport = GetBindingSupport(left, structureBinder);
return(bindingSignatureSupport != null && (ExpressionHelper.IsConstant(right) || right is UnaryExpression));
}
private static void UpdateValuePredicateType(BindingSignatureSupport signatureSupport, BinaryExpression binaryExpression)
{
// Only modify the ValuePredicateType if it already is "Equals" or "Empty". This is pending a refactor
// of BindingSignatureSupport to include a negation property and the removal of NotEquals
if (signatureSupport.NodeType != ValuePredicateType.Equal && signatureSupport.NodeType != ValuePredicateType.Empty)
{
return;
}
// First check the NodeType. Binaries joined with "!= true" will have a NodeType of NotEqual
switch (binaryExpression.NodeType)
{
case ExpressionType.Equal:
signatureSupport.NodeType = ValuePredicateType.Equal;
break;
case ExpressionType.NotEqual:
signatureSupport.NodeType = ValuePredicateType.NotEqual;
break;
case ExpressionType.GreaterThan:
signatureSupport.NodeType = ValuePredicateType.GreaterThan;
break;
case ExpressionType.GreaterThanOrEqual:
signatureSupport.NodeType = ValuePredicateType.GreaterThanOrEqual;
break;
case ExpressionType.LessThan:
signatureSupport.NodeType = ValuePredicateType.LessThan;
break;
case ExpressionType.LessThanOrEqual:
signatureSupport.NodeType = ValuePredicateType.LessThanOrEqual;
break;
}
// Then check the Method, which might be an operator
if (binaryExpression.Method != null)
{
switch (binaryExpression.Method.Name)
{
case "op_Inequality":
signatureSupport.NodeType = ValuePredicateType.NotEqual;
break;
}
}
}
public override FieldSelectorExpression CreateFieldSelector(MemberExpression expression, BindingSignatureSupport reportedSignatureSupport)
{
var attrib = GetAutoAttribute(expression);
return(attrib == null?base.CreateFieldSelector(expression, reportedSignatureSupport) : new FieldSelectorExpression(attrib.Alias));
}
/// <summary>
/// Creates a <see cref="FieldSelectorExpression"/> from a <see cref="MethodCallExpression"/>.
/// </summary>
/// <param name="expression">The expression.</param>
/// <param name="reportedSignatureSupport">A component outlining the supported expression structure of this provider.</param>
/// <returns></returns>
/// <remarks></remarks>
public override FieldSelectorExpression CreateFieldSelector(MethodCallExpression expression, BindingSignatureSupport reportedSignatureSupport)
{
switch (expression.Method.Name)
{
case "Field":
// This is an extension method for the RenderViewModel so the first argument is the extended object
return(new FieldSelectorExpression(((ConstantExpression)expression.Arguments[1]).Value.ToString()));
case "StringField":
// This is an extension method for the RenderViewModel so the first argument is the extended object
return(new FieldSelectorExpression(((ConstantExpression)expression.Arguments[1]).Value.ToString()));
case "NumberField":
// This is an extension method for the RenderViewModel so the first argument is the extended object
return(new FieldSelectorExpression(((ConstantExpression)expression.Arguments[1]).Value.ToString()));
case "BooleanField":
// This is an extension method for the RenderViewModel so the first argument is the extended object
return(new FieldSelectorExpression(((ConstantExpression)expression.Arguments[1]).Value.ToString()));
case "get_Item":
// This is the default accessor of a Dictionary, so check if the parent object is supported too
if (ExpressionHelper.IsMember(expression.Object) && IsSupportedMember(expression.Object as MemberExpression).SignatureSupportType != SignatureSupportType.NotSupported)
{
return(new FieldSelectorExpression(((ConstantExpression)expression.Arguments[0]).Value.ToString()));
}
break;
}
return(base.CreateFieldSelector(expression, reportedSignatureSupport));
}
/// <summary>
/// Gets a <see cref="FieldSelectorExpression"/> from an expression it the <paramref name="bindingSignatureSupport"/> identifies it as supported.
/// </summary>
/// <param name="left">The left.</param>
/// <param name="structureBinder">The structure binder.</param>
/// <param name="bindingSignatureSupport">The binding signature support.</param>
/// <returns></returns>
/// <remarks></remarks>
public static FieldSelectorExpression GetFieldSelector(Expression left, AbstractQueryStructureBinder structureBinder, BindingSignatureSupport bindingSignatureSupport)
{
switch (bindingSignatureSupport.SignatureSupportType)
{
case SignatureSupportType.SupportedAsFieldName:
if (ExpressionHelper.IsMember(left))
{
return(structureBinder.CreateFieldSelector(left as MemberExpression, bindingSignatureSupport));
}
else if (ExpressionHelper.IsMethod(left))
{
return(structureBinder.CreateFieldSelector(left as MethodCallExpression, bindingSignatureSupport));
}
break;
}
return(null);
}
private static SchemaSelectorExpression GetSchemaSelector(Expression left, AbstractQueryStructureBinder structureBinder, BindingSignatureSupport bindingSignatureSupport)
{
switch (bindingSignatureSupport.SignatureSupportType)
{
case SignatureSupportType.SupportedAsSchemaAlias:
if (ExpressionHelper.IsMember(left))
{
return(structureBinder.CreateSchemaSelector(left as MemberExpression, bindingSignatureSupport));
}
else if (ExpressionHelper.IsMethod(left))
{
return(structureBinder.CreateSchemaSelector(left as MethodCallExpression, bindingSignatureSupport));
}
break;
}
return(null);
}
/// <summary>
/// Converts a <see cref="BinaryExpression"/> to a field predicate expression, if supported and convertible.
/// </summary>
/// <param name="expression">The expression.</param>
/// <param name="structureBinder">The structure binder.</param>
/// <returns></returns>
/// <remarks></remarks>
public static Expression ConvertToFieldPredicate(BinaryExpression expression, AbstractQueryStructureBinder structureBinder)
{
if (IsConvertibleBinary(expression, structureBinder))
{
var left = expression.Left;
// Check if the left had side is a Unary wrapping a DynamicMemberMetadata call just to get the type right
var unaryLeft = left as UnaryExpression;
if (unaryLeft != null)
{
var methodLeft = unaryLeft.Operand as MethodCallExpression;
if (methodLeft != null && methodLeft.Method == DynamicMemberMetadata.GetMemberMethod)
{
left = methodLeft;
}
}
// First assume that the right hand side of the binary is a constant
ConstantExpression right = expression.Right as ConstantExpression;
// If it's not, it might be a unary (e.g. "convert value to object" if it's from DynamicMemberMetadata)
if (right == null)
{
var unary = expression.Right as UnaryExpression;
if (unary != null)
{
// If it was a unary, ignore the operator and just go for the operand (the value)
right = unary.Operand as ConstantExpression;
}
}
BindingSignatureSupport leftBindingSignatureSupport = GetBindingSupport(left, structureBinder);
// Update the ValuePredicateType based on the expression which might reference an operator or a NodeType of NotEqual etc.
UpdateValuePredicateType(leftBindingSignatureSupport, expression);
switch (leftBindingSignatureSupport.SignatureSupportType)
{
case SignatureSupportType.SupportedAsFieldName:
var selectorExpression = GetFieldSelector(left, structureBinder, leftBindingSignatureSupport);
return(new FieldPredicateExpression(selectorExpression, new FieldValueExpression(leftBindingSignatureSupport.NodeType, right.Value)));
case SignatureSupportType.SupportedAsFieldValue:
var methodCallExpression = ((MethodCallExpression)left);
if (ExpressionHelper.IsMethod(left))
{
var fieldValueExpression = structureBinder
.CreateFieldValueExpression(methodCallExpression, leftBindingSignatureSupport);
var objectOfMethod = methodCallExpression.Object;
var bindingSupportForMethodObject = GetBindingSupport(objectOfMethod, structureBinder);
var fieldSelector = GetFieldSelector(objectOfMethod, structureBinder, bindingSupportForMethodObject);
return(new FieldPredicateExpression(fieldSelector, fieldValueExpression));
}
break;
case SignatureSupportType.SupportedAsSchemaAlias:
var schemaSelectorExpression = GetSchemaSelector(left, structureBinder, leftBindingSignatureSupport);
return
(new SchemaPredicateExpression(
new SchemaSelectorExpression(schemaSelectorExpression.Name),
new SchemaValueExpression(leftBindingSignatureSupport.NodeType, right.Value)));
}
}
return(expression);
}
/// <summary>
/// Creates a <see cref="FieldSelectorExpression"/> from a <see cref="MethodCallExpression"/>.
/// </summary>
/// <param name="expression">The expression.</param>
/// <param name="reportedSignatureSupport">A component outlining the supported expression structure of this provider.</param>
/// <returns></returns>
/// <remarks></remarks>
public override FieldSelectorExpression CreateFieldSelector(MethodCallExpression expression, BindingSignatureSupport reportedSignatureSupport)
{
switch (expression.Method.Name)
{
case "Attribute":
// This is an extension method for the Persistence model so the first argument is the extended object
if (expression.Arguments.Count == 3)
{
//if there are 3 arguments, then we are selecting a field by name with a value key
return(new FieldSelectorExpression(
((ConstantExpression)expression.Arguments[1]).Value.ToString(),
((ConstantExpression)expression.Arguments[2]).Value.ToString()));
}
if (expression.Arguments.Count == 2)
{
//if there are 2 arguments, then we are selecting a field only by name regardless of the value key
return(new FieldSelectorExpression(((ConstantExpression)expression.Arguments[1]).Value.ToString()));
}
break;
case "get_Item":
// This is the default accessor of a Dictionary, so check if the parent object is supported too
if (ExpressionHelper.IsMember(expression.Object) && IsSupportedMember(expression.Object as MemberExpression).SignatureSupportType != SignatureSupportType.NotSupported)
{
return(new FieldSelectorExpression(((ConstantExpression)expression.Arguments[0]).Value.ToString()));
}
// There are two dictionaries on this model, the TypedAttributeCollection and its child TypedAttributeValueCollection.
// Make sure we're getting the field name from the TypedAttributeCollection indexer. To do this, access the MemberExpression
// "one up the chain" and recurse back into this method.
if (ExpressionHelper.IsMember(expression.Object) && ExpressionHelper.IsMethod(((MemberExpression)expression.Object).Expression))
{
return(CreateFieldSelector(((MemberExpression)expression.Object).Expression as MethodCallExpression, reportedSignatureSupport));
}
break;
}
return(base.CreateFieldSelector(expression, reportedSignatureSupport));
}
/// <summary>
/// Creates a field selector.
/// </summary>
/// <param name="fieldName">Name of the field.</param>
/// <param name="innerFieldName">Name of the inner field.</param>
/// <param name="reportedSignatureSupport">The reported signature support.</param>
/// <returns></returns>
public override FieldSelectorExpression CreateFieldSelector(string fieldName, string innerFieldName, BindingSignatureSupport reportedSignatureSupport)
{
switch (fieldName)
{
case "Name":
return(new FieldSelectorExpression("system-internal-node-name", fieldName));
case "UrlName":
return(new FieldSelectorExpression("system-internal-node-name", fieldName));
case "Template":
case "TemplateId":
case "CurrentTemplate":
return(new FieldSelectorExpression("system-internal-selected-template", "TemplateId"));
default:
return(base.CreateFieldSelector(fieldName, innerFieldName, reportedSignatureSupport));
}
}