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);
}
internal override Expression VisitMemberAccess(MemberExpression m)
{
if (MetaPosition.AreSameMember(m.Member, association.ThisMember.Member))
{
var keyValues = GetKeyValues(Visit(m.Expression), association.ThisKey);
return(WhereClauseFromSourceAndKeys(otherSouce, association.OtherKey.ToArray(), keyValues));
}
var expression = Visit(m.Expression);
if (expression != m.Expression)
{
if (expression.Type != m.Expression.Type && m.Member.Name == "Count" && TypeSystem.IsSequenceType(expression.Type))
{
return(Expression.Call(typeof(Enumerable), "Count", new Type[1]
{
TypeSystem.GetElementType(expression.Type)
}, expression));
}
return(Expression.MakeMemberAccess(expression, m.Member));
}
return(m);
}
private static bool IsNullableHasValue(SqlMember m)
{
return(TypeSystem.IsNullableType(m.Expression.ClrType) && m.Member.Name == "HasValue");
}