Method _getUpstreamSourceManagers

src/data/helper/sourceManager.ts:429–445

* PENDING: Is it fast enough? * If no upstream, return empty array.

()

     * If no upstream, return empty array.
     */
    private _getUpstreamSourceManagers(): SourceManager[] {
        // Always get the relationship from the raw option.
        // Do not cache the link of the dependency graph, so that
        // there is no need to update them when change happens.
        const sourceHost = this._sourceHost;

        if (isSeries(sourceHost)) {
            const datasetModel = querySeriesUpstreamDatasetModel(sourceHost);
            return !datasetModel ? [] : [datasetModel.getSourceManager()];
        }
        else {
            return map(
                queryDatasetUpstreamDatasetModels(sourceHost as DatasetModel),
                datasetModel => datasetModel.getSourceManager()
            );
        }
    }

    private _getSourceMetaRawOption(): SourceMetaRawOption {
        const sourceHost = this._sourceHost;