static public IEnumerable <Key> Where <Key>(this BTreeBase <Key, Key> sourceCollection, Expression <Func <Key, bool> > expr)
#if WINDOWS_PHONE
where Key : new()
#endif
{
if (sourceCollection != null)
{
bool noIndex = true;
SessionBase session = sourceCollection.Session;
CompareByField <Key> comparer = sourceCollection.Comparer as CompareByField <Key>;
BinaryExpression binExp = expr.Body as BinaryExpression;
if (binExp != null && canUseIndex <Key>(sourceCollection, binExp, comparer))
{
session.WaitForIndexUpdates();
switch (expr.Body.NodeType)
{
case ExpressionType.AndAlso:
{
noIndex = AndUseIndex(sourceCollection, binExp) == false;
if (noIndex == false)
{
foreach (var x in And <Key>(sourceCollection, binExp))
{
yield return(x);
}
}
else
{
BinaryExpression leftExpr = (BinaryExpression)binExp.Left;
binExp = leftExpr;
switch (binExp.NodeType)
{
case ExpressionType.Equal:
{
noIndex = EqualUseIndex <Key>(sourceCollection, binExp) == false;
if (noIndex == false)
{
IEnumerable <Key> equal = Equal <Key>(sourceCollection, binExp);
IEnumerable <Key> result = equal.Where <Key>(expr.Compile());
foreach (Key resultItem in result)
{
yield return(resultItem);
}
}
yield break;
}
case ExpressionType.LessThan:
{
noIndex = LessThanUseIndex <Key>(sourceCollection, binExp) == false;
if (noIndex == false)
{
IEnumerable <Key> lessThan = LessThan <Key>(sourceCollection, binExp);
IEnumerable <Key> result = lessThan.Where <Key>(expr.Compile());
foreach (Key resultItem in result)
{
yield return(resultItem);
}
}
yield break;
}
case ExpressionType.LessThanOrEqual:
{
noIndex = LessThanOrEqualUseIndex <Key>(sourceCollection, binExp) == false;
if (noIndex == false)
{
IEnumerable <Key> lessThan = LessThanOrEqual <Key>(sourceCollection, binExp);
IEnumerable <Key> result = lessThan.Where <Key>(expr.Compile());
foreach (Key resultItem in result)
{
yield return(resultItem);
}
}
yield break;
}
case ExpressionType.GreaterThan:
{
noIndex = GreaterThanUseIndex <Key>(sourceCollection, binExp) == false;
if (noIndex == false)
{
IEnumerable <Key> greaterThan = GreaterThan <Key>(sourceCollection, binExp);
IEnumerable <Key> result = greaterThan.Where <Key>(expr.Compile());
foreach (Key resultItem in result)
{
yield return(resultItem);
}
}
yield break;
}
case ExpressionType.GreaterThanOrEqual:
{
noIndex = GreaterThanOrEqualUseIndex <Key>(sourceCollection, binExp) == false;
if (noIndex == false)
{
IEnumerable <Key> greaterThan = GreaterThanOrEqual <Key>(sourceCollection, binExp);
IEnumerable <Key> result = greaterThan.Where <Key>(expr.Compile());
foreach (Key resultItem in result)
{
yield return(resultItem);
}
}
yield break;
}
}
;
}
}
break;
case ExpressionType.Equal:
{
noIndex = EqualUseIndex <Key>(sourceCollection, binExp) == false;
if (noIndex == false)
{
foreach (var x in Equal <Key>(sourceCollection, binExp))
{
yield return(x);
}
}
}
break;
case ExpressionType.GreaterThan:
{
noIndex = GreaterThanUseIndex <Key>(sourceCollection, binExp) == false;
if (noIndex == false)
{
foreach (var x in GreaterThan <Key>(sourceCollection, binExp))
{
yield return(x);
}
}
}
break;
case ExpressionType.GreaterThanOrEqual:
{
noIndex = GreaterThanOrEqualUseIndex <Key>(sourceCollection, binExp) == false;
if (noIndex == false)
{
foreach (var x in GreaterThanOrEqual <Key>(sourceCollection, binExp))
{
yield return(x);
}
}
}
break;
case ExpressionType.LessThan:
{
noIndex = LessThanUseIndex <Key>(sourceCollection, binExp) == false;
if (noIndex == false)
{
foreach (var x in LessThan <Key>(sourceCollection, binExp))
{
yield return(x);
}
}
}
break;
case ExpressionType.LessThanOrEqual:
{
noIndex = LessThanOrEqualUseIndex <Key>(sourceCollection, binExp) == false;
if (noIndex == false)
{
foreach (var x in LessThanOrEqual <Key>(sourceCollection, binExp))
{
yield return(x);
}
}
}
break;
}
}
if (noIndex) //no index? just do it the normal slow way then...
{
IEnumerable <Key> sourceEnum;
if (sourceCollection.UsesOidShort)
{
BTreeSetOidShort <Key> c = (BTreeSetOidShort <Key>)sourceCollection;
sourceEnum = c.AsEnumerable <Key>();
}
else
{
BTreeSet <Key> c = (BTreeSet <Key>)sourceCollection;
sourceEnum = c.AsEnumerable <Key>();
}
IEnumerable <Key> result = sourceEnum.Where <Key>(expr.Compile());
foreach (Key resultItem in result)
{
yield return(resultItem);
}
}
}
}
