private IGraphQueryStep BuildQueryPlanForPattern(PatternMatchElementExpression patternExpression, int start)
{
var prev = BuildQueryPlanForMatchNode(patternExpression.Path[start]);
for (int i = start + 1; i < patternExpression.Path.Length; i += 2)
{
if (patternExpression.Path[i].Recursive == null)
{
var next = i + 1 < patternExpression.Path.Length ?
BuildQueryPlanForMatchNode(patternExpression.Path[i + 1]) :
null;
prev = BuildQueryPlanForEdge(prev, next, patternExpression.Path[i]);
}
else
{
return(BuildQueryPlanForRecursiveEdge(prev, i, patternExpression));
}
}
return(prev);
}
private IGraphQueryStep BuildQueryPlanForRecursiveEdge(IGraphQueryStep left, int index, PatternMatchElementExpression patternExpression)
{
var recursive = patternExpression.Path[index].Recursive.Value;
var pattern = recursive.Pattern;
var steps = new List <SingleEdgeMatcher>((pattern.Count + 1) / 2);
for (int i = 0; i < pattern.Count; i += 2)
{
if (GraphQuery.WithEdgePredicates.TryGetValue(pattern[i].Alias, out var recursiveEdge) == false)
{
throw new InvalidOperationException($"BuildQueryPlanForEdge was invoked for recursive alias='{pattern[i].Alias}' which suppose to be an edge but no corresponding WITH EDGE clause was found.");
}
steps.Add(new SingleEdgeMatcher
{
IncludedEdges = new Dictionary <string, Sparrow.Json.BlittableJsonReaderObject>(StringComparer.OrdinalIgnoreCase),
QueryParameters = _query.QueryParameters,
Edge = recursiveEdge,
Results = new List <Match>(),
Right = i + 1 < pattern.Count ? BuildQueryPlanForMatchNode(pattern[i + 1]) : null,
EdgeAlias = pattern[i].Alias
});
}
var recursiveStep = new RecursionQueryStep(left, steps, recursive, recursive.GetOptions(_query.Metadata, _query.QueryParameters), _token)
{
CollectIntermediateResults = CollectIntermediateResults
};
if (index + 1 < patternExpression.Path.Length)
{
if (patternExpression.Path[index + 1].Recursive.HasValue)
{
throw new InvalidQueryException("Two adjacent 'recursive' queries are not allowed", GraphQuery.QueryText);
}
if (patternExpression.Path[index + 1].IsEdge)
{
var nextPlan = BuildQueryPlanForPattern(patternExpression, index + 2);
nextPlan = BuildQueryPlanForEdge(recursiveStep, nextPlan, patternExpression.Path[index + 1]);
recursiveStep.SetNext(nextPlan.GetSingleGraphStepExecution());
}
else
{
var nextPlan = BuildQueryPlanForPattern(patternExpression, index + 1);
recursiveStep.SetNext(nextPlan.GetSingleGraphStepExecution());
}
}
return(recursiveStep);
}
