public static bool Test(Expression ex, params MemberInfo[] safeMembers)
{
var visitor = new IsConditionSafeVisitor();
visitor.SafeMembers = safeMembers;
visitor.Visit(ex);
return(visitor.IsSafe);
}
/// <summary>
/// Tries to combine nested filters;
/// move 'MergeByName' nodes out of filter, if possible
/// </summary>
QueryNode ReorderFilter(Filter filter)
{
if (filter.Target is Filter)
{
// x.Filter(y).Filter(z) -> x.Filter(y && z)
Filter innerFilter = (Filter)filter.Target;
return(ReorderFilter(new Filter(innerFilter.Target, innerFilter.Conditions.Concat(filter.Conditions).ToArray())));
}
else if (filter.Target is MergeByName)
{
// x.MergeByName().Filter(<criteria>) -> x.Filter(x, <criteria>).MergeByName() for some safe criterias
QueryNode innerTarget = filter.Target.Target;
var conditionsToMoveIntoFilter = filter.Conditions.Where(c => IsConditionSafeVisitor.Test(c, SafeMembersForMoveIntoMergeByName)).ToArray();
if (conditionsToMoveIntoFilter.Length != 0)
{
MergeByName newTarget = new MergeByName(ReorderFilter(new Filter(innerTarget, conditionsToMoveIntoFilter)));
var conditionsKeptOutsideFilter = filter.Conditions.Except(conditionsToMoveIntoFilter).ToArray();
if (conditionsKeptOutsideFilter.Length == 0)
{
return(newTarget);
}
else
{
return(new Filter(newTarget, conditionsKeptOutsideFilter));
}
}
else
{
return(filter);
}
}
else
{
return(filter);
}
}
public static bool Test(Expression ex, params MemberInfo[] safeMembers)
{
var visitor = new IsConditionSafeVisitor();
visitor.SafeMembers = safeMembers;
visitor.Visit(ex);
return visitor.IsSafe;
}
QueryNode VisitMergeByName(MergeByName merge)
{
// First optimize the Target expression
QueryNode target = Visit(merge.Target);
if (target is MergeByName)
{
// x.MergeByName().MergeByName() -> x.MergeByName()
return(target);
}
if (target == AllCalls.Instance)
{
// AllCalls.MergeByName() -> AllFunctions
return(new AllFunctions());
}
if (target is Filter && target.Target == AllCalls.Instance)
{
// AllCalls.Filter(criteria).MergeByName() -> AllFunctions.Filter(criteria)
// If criteria accesses no CallTreeNode properties except for NameMapping.
// Criteria of the form 'start <= c.DataSetID && c.DataSetID <= end' will be converted into AllFunctions(start,end)
List <LambdaExpression> newConditions = new List <LambdaExpression>();
bool allIsSafe = true;
int startDataSetID = -1;
int endDataSetID = -1;
foreach (LambdaExpression condition in ((Filter)target).Conditions)
{
if (IsConditionSafeVisitor.Test(condition, SafeMembersForMoveIntoMergeByName))
{
newConditions.Add(condition);
}
else if (condition.Body.NodeType == ExpressionType.AndAlso && startDataSetID < 0)
{
// try match 'constant <= c.DataSetID && c.DataSetID <= constant', but only if we
// haven't found it already (startDataSetID is still -1)
BinaryExpression bin = (BinaryExpression)condition.Body;
if (bin.Left.NodeType == ExpressionType.LessThanOrEqual && bin.Right.NodeType == ExpressionType.LessThanOrEqual)
{
BinaryExpression left = (BinaryExpression)bin.Left;
BinaryExpression right = (BinaryExpression)bin.Right;
if (left.Left.NodeType == ExpressionType.Constant && left.Right.NodeType == ExpressionType.MemberAccess &&
right.Left.NodeType == ExpressionType.MemberAccess && right.Right.NodeType == ExpressionType.Constant &&
((MemberExpression)left.Right).Member == SingleCall.DataSetIdField &&
((MemberExpression)right.Left).Member == SingleCall.DataSetIdField)
{
startDataSetID = (int)GetConstantValue(left.Left);
endDataSetID = (int)GetConstantValue(right.Right);
}
else
{
allIsSafe = false;
}
}
else
{
allIsSafe = false;
}
}
else
{
allIsSafe = false;
}
}
if (allIsSafe)
{
if (newConditions.Count > 0)
{
return(new Filter(new AllFunctions(startDataSetID, endDataSetID), newConditions.ToArray()));
}
else
{
return(new AllFunctions(startDataSetID, endDataSetID));
}
}
}
return(new MergeByName(target));
}
