protected override Expression VisitMethodCall(MethodCallExpression node)
{
var call_object = (node.Object) as MemberExpression;
if (call_object == null)
{
goto method_call_cleanup;
}
var member_string = _get_member_string(call_object);
string index_access_method;
if (m_index_access_table.TryGetValue(member_string, out index_access_method) &&
index_access_method == node.Method.Name)
{
if (node.Arguments.Count != 1)
{
goto method_call_cleanup;
}
var arg = node.Arguments[0];
string query_string = null;
if (arg.NodeType == ExpressionType.Constant)
{
query_string = (string)(arg as ConstantExpression).Value;
}
else
{
query_string = _evaluate_expression <string>(arg);
/* We have to update the expression to avoid re-entering the expression */
node = node.Update(
node.Object,
new List <Expression> {
Expression.Constant(query_string, s_string_type)
});
}
if (query_string == null)
{
goto method_call_cleanup;
}
/*
* @note Gotcha. It's an index query method call!
*/
m_current_node = new IndexQueryTreeNode(IndexQueryTreeNode.NodeType.QUERY);
m_current_node.queryTarget = member_string;
m_current_node.queryString = query_string;
}
/*
* @note We don't have to go deeper into the rabbit hole,
* as we cannot evaluate the method call.
*/
method_call_cleanup:
return(node);
}
void UnaryBuildTree(IndexQueryTreeNode.NodeType type, UnaryExpression node)
{
IndexQueryTreeNode query_node = new IndexQueryTreeNode {
type = type, children = new List <IndexQueryTreeNode>()
};
VisitChildren(query_node.children, node.Operand);
if (query_node.children.Count != 0)
{
m_current_node = query_node;
}
}
IndexQueryTreeNode VisitChild(Expression child)
{
IndexQueryTreeNode original_node = m_current_node;
Visit(child);
if (m_current_node != original_node)
{
var ret = m_current_node;
m_current_node = original_node;
return(ret);
}
else
{
return(null);
}
}
internal HashSet <long> Execute(IndexQueryTreeNode node)
{
if (node == null)
{
return(null);
}
HashSet <long> ret;
switch (node.type)
{
case IndexQueryTreeNode.NodeType.AND:
ret = Execute(node.children[0]);
foreach (var child in node.children.Skip(1))
{
ret.IntersectWith(Execute(child));
}
break;
case IndexQueryTreeNode.NodeType.OR:
ret = Execute(node.children[0]);
foreach (var child in node.children.Skip(1))
{
foreach (var id in Execute(child))
{
ret.Add(id);
}
}
break;
case IndexQueryTreeNode.NodeType.QUERY:
if (node.queryString != null)
{
ret = new HashSet <long>(m_substring_query[node.queryTarget](node.queryString));
}
else
{
ret = new HashSet <long>(m_substring_query_wildcard[node.queryTarget](node.wildcard_query));
}
break;
default:
throw new NotImplementedException("Internal error T5012.");
}
return(ret);
}
private void _equality_build_tree(BinaryExpression node, bool is_equal)
{
if (node.Left.Type != s_bool_type || node.Right.Type != s_bool_type)
{
return;
}
bool?constant = null;
List <Expression> exp = new List <Expression>();
Func <bool, bool, bool> _equal_helper = (lhs, rhs) => is_equal? lhs == rhs : lhs != rhs;
bool?lconstant = _constant_boolean_exp_eval(node.Left);
bool?rconstant = _constant_boolean_exp_eval(node.Right);
if (lconstant.HasValue)
{
constant = lconstant;
}
else
{
exp.Add(node.Left);
}
if (rconstant.HasValue)
{
constant = rconstant;
}
else
{
exp.Add(node.Right);
}
if (lconstant.HasValue && rconstant.HasValue)
{
m_current_node = new IndexQueryTreeNode(
_equal_helper(lconstant.Value, rconstant.Value)?
IndexQueryTreeNode.NodeType.UNIVERSE:IndexQueryTreeNode.NodeType.EMPTY);
return;
}
IndexQueryTreeNode query_node;
IndexQueryTreeNode child_node;
if (constant.HasValue)
{
child_node = VisitChild(exp[0]);
if (child_node == null)
{
m_current_node = new IndexQueryTreeNode(
_equal_helper(constant.Value, true)?
IndexQueryTreeNode.NodeType.UNIVERSE: IndexQueryTreeNode.NodeType.EMPTY);
}
else
{
if (_equal_helper(constant.Value, true))
{ /* keep m_current_node as is */
}
else
{
query_node = new IndexQueryTreeNode(IndexQueryTreeNode.NodeType.NOT)
{
children = new List <IndexQueryTreeNode> {
child_node
}
};
m_current_node = query_node;
}
}
}
else
{
query_node = new IndexQueryTreeNode(
_equal_helper(true, true)? IndexQueryTreeNode.NodeType.XNOR:IndexQueryTreeNode.NodeType.XOR)
{
children = new List <IndexQueryTreeNode>()
};
VisitChildren(query_node.children, node.Left, node.Right);
switch (query_node.children.Count)
{
case 0:
case 1:
/* no index query actions, as we cannot analyse the semantics */
break;
case 2:
/* we have query actions on both sides */
m_current_node = query_node;
break;
default:
throw new Exception("Internal error T5010");
}
}
}
internal IndexQueryTreeNode Optimize()
{
if (children != null)
{
List <IndexQueryTreeNode> new_child_list = new List <IndexQueryTreeNode>();
foreach (var child in children)
{
var new_child = child.Optimize();
if (new_child != null)
{
new_child_list.Add(new_child);
}
}
this.children = new_child_list;
}
if (type == NodeType.QUERY || type == NodeType.UNIVERSE || type == NodeType.EMPTY)
{
return(this);
}
if (children.Count == 0)
{
return(null);
}
IndexQueryTreeNode universe = null;
IndexQueryTreeNode empty = null;
IndexQueryTreeNode normal = null;
foreach (var child in children)
{
if (child.type == NodeType.EMPTY)
{
empty = child;
}
else if (child.type == NodeType.UNIVERSE)
{
universe = child;
}
else
{
normal = child;
}
}
switch (type)
{
case NodeType.NOT:
/* Drop NOT queries */
if (children[0].type == NodeType.NOT)
{
return(children[0].children[0]);
}
else
{
return(null);
}
case NodeType.XNOR:
case NodeType.XOR:
/* Not implemented. */
return(null);
case NodeType.AND:
{
if (empty != null)
{
return(empty);
}
if (universe != null)
{
return(normal);
}
if (children.Count == 1)
{
return(children[0]);
}
else
{
return(this);
}
}
case NodeType.OR:
{
if (empty != null)
{
return(normal);
}
if (universe != null)
{
return(universe);
}
if (children.Count == 1)
{
return(children[0]);
}
else
{
return(this);
}
}
default:
throw new Exception("Internal error T5011.");
}
}
