protected override Expression VisitMember(MemberExpression expression)
{
var isIdentifier = _isEntityDecider.IsIdentifier(expression.Expression.Type, expression.Member.Name);
if (isIdentifier)
{
_hasIdentifier = true;
}
if (!isIdentifier)
{
_memberExpressionDepth++;
}
var result = base.VisitMember(expression);
if (!isIdentifier)
{
_memberExpressionDepth--;
}
if (_isEntityDecider.IsEntity(expression.Type) &&
((_requiresJoinForNonIdentifier && !_hasIdentifier) || _memberExpressionDepth > 0) &&
_joiner.CanAddJoin(expression))
{
var key = ExpressionKeyVisitor.Visit(expression, null);
return(_joiner.AddJoin(result, key));
}
_hasIdentifier = false;
return(result);
}
public static string Visit(Expression expression, IDictionary <ConstantExpression, NamedParameter> parameters)
{
var visitor = new ExpressionKeyVisitor(parameters);
visitor.Visit(expression);
return(visitor.ToString());
}
// We would usually get NULL if one of our inner member expresions was null.
// However, it's possible a method call will convert the null value from the failed join into a non-null value.
// This could be optimized by actually checking what the method does. For example StartsWith("s") would leave null as null and would still allow us to inner join.
//protected override Expression VisitMethodCall(MethodCallExpression expression)
//{
// Expression result = base.VisitMethodCall(expression);
// return result;
//}
protected override Expression VisitMember(MemberExpression expression)
{
// The member expression we're visiting might be on the end of a variety of things, such as:
// a.B
// a.B.C
// (a.B ?? a.C).D
// I'm not sure what processing re-linq does to strange member expressions.
// TODO: I suspect this code doesn't add the right joins for the last case.
var isIdentifier = _isEntityDecider.IsIdentifier(expression.Expression.Type, expression.Member.Name);
if (!isIdentifier)
{
_memberExpressionDepth++;
}
var result = base.VisitMember(expression);
if (!isIdentifier)
{
_memberExpressionDepth--;
}
ExpressionValues values = _values.Pop().Operation(pvs => pvs.MemberAccess(expression.Type));
if (_isEntityDecider.IsEntity(expression.Type))
{
// Don't add joins for things like a.B == a.C where B and C are entities.
// We only need to join B when there's something like a.B.D.
var key = ExpressionKeyVisitor.Visit(expression, null);
if (_memberExpressionDepth > 0 &&
_joiner.CanAddJoin(expression))
{
result = _joiner.AddJoin(result, key);
}
values.MemberExpressionValuesIfEmptyOuterJoined[key] = PossibleValueSet.CreateNull(expression.Type);
}
SetResultValues(values);
return(result);
}
