internal override SqlExpression VisitTreat(SqlUnary t)
{
t.Operand = this.VisitExpression(t.Operand);
Type treatType = t.ClrType;
Type originalType = model.GetMetaType(t.Operand.ClrType).InheritanceRoot.Type;
// .NET nullability rules are that typeof(int)==typeof(int?). Let's be consistent with that:
treatType = TypeSystem.GetNonNullableType(treatType);
originalType = TypeSystem.GetNonNullableType(originalType);
if (treatType == originalType)
{
return(t.Operand);
}
else if (treatType.IsAssignableFrom(originalType))
{
t.Operand.SetClrType(treatType);
return(t.Operand);
}
else if (!treatType.IsAssignableFrom(originalType) && !originalType.IsAssignableFrom(treatType))
{
if (!treatType.IsInterface && !originalType.IsInterface) // You can't tell when there's an interface involved.
// We statically know the TREAT will result in NULL.
{
return(sql.TypedLiteralNull(treatType, t.SourceExpression));
}
}
//return base.VisitTreat(t);
return(t);
}
/// <summary>
/// Get a MetaType that represents the dynamic type of the given node.
/// </summary>
internal static MetaType GetSourceMetaType(SqlNode node, MetaModel model)
{
Visitor v = new Visitor();
v.Visit(node);
Type type = v.sourceType;
type = TypeSystem.GetNonNullableType(type); // Emulate CLR's behavior: strip nullability from type.
return(model.GetMetaType(type));
}
internal override SqlRow VisitRow(SqlRow row)
{
for (int i = 0, n = row.Columns.Count; i < n; i++)
{
SqlColumn col = row.Columns[i];
SqlExpression expr = this.VisitExpression(col.Expression);
if (expr != null)
{
if (TypeSystem.GetNonNullableType(col.ClrType) != TypeSystem.GetNonNullableType(expr.ClrType))
{
throw Error.ColumnClrTypeDoesNotAgreeWithExpressionsClrType();
}
}
}
return(row);
}
internal SqlUnary UnaryValueOf(SqlExpression expression, Expression sourceExpression)
{
Type valueType = TypeSystem.GetNonNullableType(expression.ClrType);
return(new SqlUnary(SqlNodeType.ValueOf, valueType, expression.SqlType, expression, null, sourceExpression));
}
internal override SqlNode Visit(SqlNode node)
{
if (node == null)
{
return(null);
}
sourceExpression = node as SqlExpression;
if (sourceExpression != null)
{
Type type = sourceExpression.ClrType;
UnwrapStack unwrap = this.UnwrapSequences;
while (unwrap != null)
{
if (unwrap.Unwrap)
{
type = TypeSystem.GetElementType(type);
}
unwrap = unwrap.Last;
}
sourceType = type;
}
if (sourceType != null && TypeSystem.GetNonNullableType(sourceType).IsValueType)
{
return(node); // Value types can't also have a dynamic type.
}
if (sourceType != null && TypeSystem.HasIEnumerable(sourceType))
{
return(node); // Sequences can't be polymorphic.
}
switch (node.NodeType)
{
case SqlNodeType.ScalarSubSelect:
case SqlNodeType.Multiset:
case SqlNodeType.Element:
case SqlNodeType.SearchedCase:
case SqlNodeType.ClientCase:
case SqlNodeType.SimpleCase:
case SqlNodeType.Member:
case SqlNodeType.DiscriminatedType:
case SqlNodeType.New:
case SqlNodeType.FunctionCall:
case SqlNodeType.MethodCall:
case SqlNodeType.Convert: // Object identity does not survive convert. It does survive Cast.
// Dig no further.
return(node);
case SqlNodeType.TypeCase:
sourceType = ((SqlTypeCase)node).RowType.Type;
return(node);
case SqlNodeType.Link:
sourceType = ((SqlLink)node).RowType.Type;
return(node);
case SqlNodeType.Table:
sourceType = ((SqlTable)node).RowType.Type;
return(node);
case SqlNodeType.Value:
SqlValue val = (SqlValue)node;
if (val.Value != null)
{
// In some cases the ClrType of a Value node may
// differ from the actual runtime type of the value.
// Therefore, we ensure here that the correct type is set.
sourceType = val.Value.GetType();
}
return(node);
}
return(base.Visit(node));
}
internal override SqlExpression VisitUnaryOperator(SqlUnary uo)
{
uo.Operand = this.VisitExpression(uo.Operand);
if (uo.NodeType != SqlNodeType.Convert)
{
return(uo);
}
ProviderType oldSqlType = uo.Operand.SqlType;
ProviderType newSqlType = uo.SqlType;
Type oldClrType = TypeSystem.GetNonNullableType(uo.Operand.ClrType);
Type newClrType = TypeSystem.GetNonNullableType(uo.ClrType);
if (newClrType == typeof(char))
{
if (oldClrType == typeof(bool))
{
throw Error.ConvertToCharFromBoolNotSupported();
}
if (oldSqlType.IsNumeric)
{
// numeric --> char
return(sql.FunctionCall(uo.ClrType, "NCHAR", new SqlExpression[] { uo.Operand }, uo.SourceExpression));
}
if (StringConversionIsSafe(oldSqlType, newSqlType))
{
if (StringConversionIsNeeded(oldSqlType, newSqlType))
{
// set the new size to the (potentially smaller) oldSqlType.Size
uo.SetSqlType(sql.TypeProvider.From(uo.ClrType, oldSqlType.HasSizeOrIsLarge ? oldSqlType.Size : (int?)null));
}
}
else
{
throw Error.UnsafeStringConversion(oldSqlType.ToQueryString(), newSqlType.ToQueryString());
}
}
else if (oldClrType == typeof(char) && (oldSqlType.IsChar || oldSqlType.IsString) && newSqlType.IsNumeric)
{
// char --> int
return(sql.FunctionCall(newClrType, sql.TypeProvider.From(typeof(int)), "UNICODE", new SqlExpression[] { uo.Operand }, uo.SourceExpression));
}
else if (newClrType == typeof(string))
{
if (oldClrType == typeof(double))
{
// use longer format if it was a double in the CLR expression
return(ConvertDoubleToString(uo.Operand, uo.ClrType));
}
else if (oldClrType == typeof(bool))
{
// use 'true' or 'false' if it was a bool in the CLR expression
return(ConvertBitToString(uo.Operand, uo.ClrType));
}
else if (StringConversionIsSafe(oldSqlType, newSqlType))
{
if (StringConversionIsNeeded(oldSqlType, newSqlType))
{
// set the new size to the (potentially smaller) oldSqlType.Size
uo.SetSqlType(sql.TypeProvider.From(uo.ClrType, oldSqlType.HasSizeOrIsLarge ? oldSqlType.Size : (int?)null));
}
}
else
{
throw Error.UnsafeStringConversion(oldSqlType.ToQueryString(), newSqlType.ToQueryString());
}
}
return(uo);
}