private SqlSelect VisitDefaultIfEmpty(Expression sequence)
{
SqlSelect select = this.VisitSequence(sequence);
SqlAlias alias = new SqlAlias(select);
SqlAliasRef aliasRef = new SqlAliasRef(alias);
SqlExpression opt = new SqlOptionalValue(
new SqlColumn(
"test",
_nodeFactory.Unary(SqlNodeType.OuterJoinedValue,
_nodeFactory.Value(typeof(int?), _typeProvider.From(typeof(int)), 1, false, _dominatingExpression)
)
),
_nodeFactory.Unary(SqlNodeType.OuterJoinedValue, aliasRef)
);
SqlSelect optSelect = new SqlSelect(opt, alias, _dominatingExpression);
alias = new SqlAlias(optSelect);
aliasRef = new SqlAliasRef(alias);
SqlExpression litNull = _nodeFactory.TypedLiteralNull(typeof(string), _dominatingExpression);
SqlSelect selNull = new SqlSelect(litNull, null, _dominatingExpression);
SqlAlias aliasNull = new SqlAlias(selNull);
SqlJoin join = new SqlJoin(SqlJoinType.OuterApply, aliasNull, alias, null, _dominatingExpression);
return new SqlSelect(aliasRef, join, _dominatingExpression);
}
internal virtual SqlExpression VisitOptionalValue(SqlOptionalValue sov) {
sov.HasValue = this.VisitExpression(sov.HasValue);
sov.Value = this.VisitExpression(sov.Value);
return sov;
}
private Type GenerateOptionalValue(SqlOptionalValue opt)
{
Diagnostics.Debug.Assert(opt.HasValue.ClrType == typeof(int?));
Label labIsNull = gen.DefineLabel();
Label labExit = gen.DefineLabel();
Type actualType = this.Generate(opt.HasValue);
Diagnostics.Debug.Assert(TypeSystem.IsNullableType(actualType));
LocalBuilder loc = gen.DeclareLocal(actualType);
gen.Emit(OpCodes.Stloc, loc);
gen.Emit(OpCodes.Ldloca, loc);
this.GenerateHasValue(actualType);
gen.Emit(OpCodes.Brfalse, labIsNull);
this.GenerateExpressionForType(opt.Value, opt.ClrType);
gen.Emit(OpCodes.Br_S, labExit);
gen.MarkLabel(labIsNull);
this.GenerateConstant(opt.ClrType, null);
gen.MarkLabel(labExit);
return opt.ClrType;
}
internal override SqlExpression VisitOptionalValue(SqlOptionalValue sov)
{
if(_isDebugMode)
{
_commandStringBuilder.Append("opt(");
this.Visit(sov.HasValue);
_commandStringBuilder.Append(", ");
this.Visit(sov.Value);
_commandStringBuilder.Append(")");
return sov;
}
else
{
throw Error.InvalidFormatNode("OptionalValue");
}
}
internal override SqlExpression VisitOptionalValue(SqlOptionalValue sov)
{
SqlExpression hasValue = this.VisitExpression(sov.HasValue);
SqlExpression value = this.VisitExpression(sov.Value);
return new SqlOptionalValue(hasValue, value);
}
internal override SqlExpression VisitOptionalValue(SqlOptionalValue sov)
{
sov.HasValue = this.VisitNamedExpression(sov.HasValue, "test");
sov.Value = this.VisitExpression(sov.Value);
return sov;
}
internal override SqlExpression VisitOptionalValue(SqlOptionalValue sov)
{
bool saveCanJoin = this.canJoin;
this.canJoin = false;
try
{
return base.VisitOptionalValue(sov);
}
finally
{
this.canJoin = saveCanJoin;
}
}