private static List <string> ConstructFollowEdgeSet(FSDescCallchainElement followEdge)
{
/***********************************************
* Syntax:
*
* FollowEdge(params string[] edgeTypes)
***********************************************/
var ret = new List <string>();
if (followEdge == null)
{
return(ret);
}
foreach (var arg in followEdge.Arguments)
{
var edge = Get <LiteralExpressionSyntax>(arg.Expression, "Expecting a string");
ThrowIf(!edge.IsKind(SyntaxKind.StringLiteralExpression), "Expecting a string", arg);
ret.Add(edge.Token.ValueText);
}
// * means wildcard.
if (ret.Any(_ => _ == "*"))
{
ret.Clear();
}
return(ret);
}
private static FanoutSearchDescriptor ConstructFanoutSearchDescriptor(List <FSDescCallchainElement> fs_callchain)
{
FanoutSearchDescriptor fs_desc = ConstructFanoutSearchOrigin(fs_callchain.First());
for (int idx = 1; idx < fs_callchain.Count; ++idx)
{
FSDescCallchainElement visitNode = fs_callchain[idx];
FSDescCallchainElement followEdge = null;
FanoutSearch.Action defaultAction = Action.Continue;
if (visitNode.Method == s_LIKQ_FollowEdge)
{
ThrowIf(++idx >= fs_callchain.Count, "The query expression cannot end with '" + s_LIKQ_FollowEdge + "'", visitNode.SyntaxNode);
followEdge = visitNode;
visitNode = fs_callchain[idx];
if (visitNode.Method == s_LIKQ_FollowEdge)
{
// two consequtive FollowEdge, use default traverse action.
--idx;
visitNode = null;
}
}
if (idx + 1 >= fs_callchain.Count)
{
// The last element should have default action Action.Return
defaultAction = Action.Return;
}
ThrowIf(visitNode.Method != s_LIKQ_VisitNode, "Expecting '" + s_LIKQ_VisitNode + "'", visitNode.SyntaxNode);
fs_desc = ConstructFanoutSearchBody(fs_desc, visitNode, followEdge, defaultAction);
}
return(fs_desc);
}
private static FanoutSearchDescriptor ConstructFanoutSearchOrigin(FSDescCallchainElement origin)
{
/***********************************************
* Syntax:
*
* 1. StartFrom(long cellid, IEnumerable<string> select = null)
* 2. StartFrom(IEnumerable<long> cellid, IEnumerable<string> select = null)
* 3. StartFrom(string queryObject, IEnumerable<string> select = null)
***********************************************/
ThrowIf(origin.Method != s_LIKQ_StartFrom, "Expecting " + s_LIKQ_StartFrom, origin.SyntaxNode);
FanoutSearchDescriptor fs_desc = new FanoutSearchDescriptor("");
fs_desc.m_origin_query = null;
ThrowIf(origin.Arguments.Count < 1 || origin.Arguments.Count > 2, "Expecting 1 or 2 arguments", origin.SyntaxNode);
ExpressionSyntax origin_cell_query = origin.Arguments[0].Expression;
ExpressionSyntax selection = origin.Arguments.Count < 2 ? null : origin.Arguments[1].Expression;
switch (origin_cell_query.Kind())
{
case SyntaxKind.ObjectCreationExpression:
case SyntaxKind.ImplicitArrayCreationExpression:
case SyntaxKind.ArrayCreationExpression:
fs_desc.m_origin = ConstructCollection <long>(origin_cell_query).ToList();
break;
case SyntaxKind.NumericLiteralExpression:
case SyntaxKind.UnaryMinusExpression:
case SyntaxKind.UnaryPlusExpression:
{
long cell_id = 0;
var parse_result = long.TryParse(origin_cell_query.ToString(), out cell_id);
ThrowIf(!parse_result, "Expecting a cell id", origin_cell_query);
fs_desc.m_origin = new List <long> {
cell_id
};
break;
}
case SyntaxKind.StringLiteralExpression:
fs_desc.m_origin_query = (origin_cell_query as LiteralExpressionSyntax).Token.ValueText;
break;
default:
throw new LambdaDSLSyntaxErrorException("Invalid starting node argument", origin_cell_query);
}
if (selection != null)
{
fs_desc.m_selectFields.Add(ConstructCollection <string>(selection).ToList());
}
return(fs_desc);
}
private static FanoutSearchDescriptor ConstructFanoutSearchBody(FanoutSearchDescriptor current, FSDescCallchainElement visitNode, FSDescCallchainElement followEdge, Action defaultTraverseAction)
{
List <string> follow_edge_set = ConstructFollowEdgeSet(followEdge);
EdgeTypeDescriptor ets = current.FollowEdge(follow_edge_set.ToArray());
if (visitNode == null)
{
return(ets.VisitNode(defaultTraverseAction));
}
else if (visitNode.Arguments.Count == 1)
{
return(ets.VisitNode(ConstructVisitNodeAction(visitNode.Arguments[0].Expression)));
}
else /*if (visitNode.Arguments.Count > 1)*/
{
return(ets.VisitNode(
ConstructVisitNodeAction(visitNode.Arguments[0].Expression),
ConstructCollection <string>(visitNode.Arguments[1].Expression) /*select*/));
}
}
