static bool EqualUseIndex <Key>(BTreeBase <Key, Key> sourceCollection, BinaryExpression binExp)
#if WINDOWS_PHONE
where Key : new()
#endif
{
SessionBase session = sourceCollection.Session;
CompareByField <Key> comparer = sourceCollection.Comparer as CompareByField <Key>;
Expression leftSide = binExp.Left;
Expression rightSide = binExp.Right;
object rightValue = GetRightValue(leftSide, rightSide);
if (leftSide.NodeType == ExpressionType.Parameter)
{
Key key = (Key)rightValue;
if (key != null)
{
if (session.TraceIndexUsage)
{
Trace.WriteLine(DateTime.Now.ToString("HH:mm:ss:fff") + " Index used with " + sourceCollection.ToString());
}
return(true);
}
}
else
{
if (comparer != null)
{
MemberExpression returnedEx = null;
if (comparer.FieldsToCompare == null)
{
comparer.SetupFieldsToCompare();
}
DataMember dataMember = comparer.FieldsToCompare[0];
if (rightValue != null && HasIndexablePropertyOnLeft <Key>(leftSide, sourceCollection, dataMember, out returnedEx))
{
if (session.TraceIndexUsage)
{
Trace.WriteLine(DateTime.Now.ToString("HH:mm:ss:fff") + " Index used with " + sourceCollection.ToString());
}
return(true);
}
}
}
return(false);
}
static bool AndUseIndex <Key>(BTreeBase <Key, Key> sourceCollection, BinaryExpression binExp)
#if WINDOWS_PHONE
where Key : new()
#endif
{
while (binExp.NodeType == ExpressionType.AndAlso)
{
BinaryExpression leftExpr = (BinaryExpression)binExp.Left;
binExp = leftExpr;
if (binExp.NodeType != ExpressionType.Equal && binExp.NodeType != ExpressionType.AndAlso)
{
return(false);
}
}
SessionBase session = sourceCollection.Session;
if (session.TraceIndexUsage)
{
Trace.WriteLine(DateTime.Now.ToString("HH:mm:ss:fff") + " Index used with " + sourceCollection.ToString());
}
return(true);
}
static bool LessThanUseIndex <Key>(BTreeBase <Key, Key> sourceCollection, BinaryExpression binExp)
#if WINDOWS_PHONE
where Key : new()
#endif
{
SessionBase session = sourceCollection.Session;
CompareByField <Key> comparer = sourceCollection.Comparer as CompareByField <Key>;
Expression leftSide = binExp.Left;
Expression rightSide = binExp.Right;
object rightValue = GetRightValue(leftSide, rightSide);
if (leftSide.NodeType == ExpressionType.Parameter)
{
Key key = (Key)rightValue;
if (key != null)
{
if (session.TraceIndexUsage)
{
Trace.WriteLine(DateTime.Now.ToString("HH:mm:ss:fff") + " Index used with " + sourceCollection.ToString());
}
return(true);
}
}
else
{
if (comparer != null)
{
//if we were able to create a hash from the right side (likely)
MemberExpression returnedEx = null;
if (comparer.FieldsToCompare == null)
{
comparer.SetupFieldsToCompare();
}
DataMember dataMember = comparer.FieldsToCompare[0];
if (rightValue != null && HasIndexablePropertyOnLeft <Key>(leftSide, sourceCollection, dataMember, out returnedEx))
{
if (session.TraceIndexUsage)
{
Trace.WriteLine(DateTime.Now.ToString("HH:mm:ss:fff") + " Index used with " + sourceCollection.ToString());
}
return(true);
}
else if (leftSide.NodeType == ExpressionType.Call)
{
// don't know yet how to handle TODO
/*MethodCallExpression expression = leftSide as MethodCallExpression;
* Trace.Out.WriteLine("Method: " + expression.Method.Name);
* Trace.Out.WriteLine("Args: ");
* foreach (var exp in expression.Arguments)
* sourceCollection where */
}
}
}
return(false);
}
