Method fillShortestPathVars

query/query.go:1767–1802

fillShortestPathVars reads value of the uid variable from mp map and fills it into From and To parameters.

(mp map[string]varValue)

// fillShortestPathVars reads value of the uid variable from mp map and fills it into From and To
// parameters.
func (sg *SubGraph) fillShortestPathVars(mp map[string]varValue) error {
	// The uidVar.Uids can be nil or have an empty uid list if the variable didn't
	// return any uids. This would mean sg.Params.From or sg.Params.To is 0 and the
	// query would return an empty result.

	if sg.Params.ShortestPathArgs.From != nil && len(sg.Params.ShortestPathArgs.From.NeedsVar) > 0 {
		fromVar := sg.Params.ShortestPathArgs.From.NeedsVar[0].Name
		uidVar, ok := mp[fromVar]
		if !ok {
			return errors.Errorf("value of from var(%s) should have already been populated",
				fromVar)
		}
		if uidVar.Uids != nil && len(uidVar.Uids.Uids) > 0 {
			if len(uidVar.Uids.Uids) > 1 {
				return errors.Errorf("from variable(%s) should only expand to 1 uid", fromVar)
			}
			sg.Params.From = uidVar.Uids.Uids[0]
		}
	}

	if sg.Params.ShortestPathArgs.To != nil && len(sg.Params.ShortestPathArgs.To.NeedsVar) > 0 {
		toVar := sg.Params.ShortestPathArgs.To.NeedsVar[0].Name
		uidVar, ok := mp[toVar]
		if !ok {
			return errors.Errorf("value of to var(%s) should have already been populated",
				toVar)
		}
		if uidVar.Uids != nil && len(uidVar.Uids.Uids) > 0 {
			if len(uidVar.Uids.Uids) > 1 {
				return errors.Errorf("to variable(%s) should only expand to 1 uid", toVar)
			}
			sg.Params.To = uidVar.Uids.Uids[0]
		}
	}
	return nil
}

// fillVars reads the value corresponding to a variable from the map mp and stores it inside
// SubGraph. This value is then later used for execution of the SubGraph.