public Task <IPhysicalOperator <RowHolder> > BuildStatement(Sql.sqlStatement statement, ITransaction tran, IPhysicalOperator <RowHolder> source, InputStringNormalizer inputStringNormalizer)
{
if (FSharpOption <Sql.where> .get_IsSome(statement.Where))
{
Sql.where whereStatement = statement.Where.Value;
IPhysicalOperator <RowHolder> filterOp = new PhyOpFilter(source, FilterStatementBuilder.EvalWhere(whereStatement, source.GetOutputColumns(), inputStringNormalizer));
return(Task.FromResult(filterOp));
}
else
{
return(Task.FromResult(source));
}
}
public static Func <RowHolder, bool> EvalWhere(Sql.where where, MetadataColumn[] metadataColumns, InputStringNormalizer stringNormalizer)
{
// TODO: This is all functional programming and nice
// but I really doubt the perf.
// Recursion + higher order functions is probably super slow...
Func <RowHolder, bool> returnFilterFunc = null;
returnFilterFunc = (rowHolder) =>
{
if (where.IsAnd)
{
Sql.where.And andStmt = (Sql.where.And) where;
Func <RowHolder, bool> leftOp = EvalWhere(andStmt.Item1, metadataColumns, stringNormalizer);
Func <RowHolder, bool> rightOp = EvalWhere(andStmt.Item2, metadataColumns, stringNormalizer);
return(leftOp(rowHolder) && rightOp(rowHolder));
}
else if (where.IsOr)
{
Sql.where.Or orStmt = (Sql.where.Or) where;
Func <RowHolder, bool> leftOp = EvalWhere(orStmt.Item1, metadataColumns, stringNormalizer);
Func <RowHolder, bool> rightOp = EvalWhere(orStmt.Item2, metadataColumns, stringNormalizer);
return(leftOp(rowHolder) || rightOp(rowHolder));
}
else if (where.IsCond)
{
Sql.where.Cond condStmt = (Sql.where.Cond) where;
Sql.value leftOp = stringNormalizer.ApplyReplacementTokens(condStmt.Item.Item1);
Sql.op op = condStmt.Item.Item2;
Sql.value rightOp = stringNormalizer.ApplyReplacementTokens(condStmt.Item.Item3);
IComparable leftOpComp, rightOpComp;
leftOpComp = ValToIComp(leftOp, ref metadataColumns, ref rowHolder);
rightOpComp = ValToIComp(rightOp, ref metadataColumns, ref rowHolder);
if (op.IsEq)
{
return(leftOpComp.CompareTo(rightOpComp) == 0);
}
else if (op.IsGe)
{
return(leftOpComp.CompareTo(rightOpComp) >= 0);
}
else if (op.IsGt)
{
return(leftOpComp.CompareTo(rightOpComp) > 0);
}
else if (op.IsLe)
{
return(leftOpComp.CompareTo(rightOpComp) <= 0);
}
else if (op.IsLt)
{
return(leftOpComp.CompareTo(rightOpComp) < 0);
}
}
throw new InvalidProgramException("Invalid state.");
};
return(returnFilterFunc);
}
