private Map<String, SearchHitField> getSearchFields(SearchContext context, int nestedSubDocId, boolean loadAllStored, Set<String> fieldNames, List<String> fieldNamePatterns, LeafReaderContext subReaderContext) {
    Map<String, SearchHitField> searchFields = null;
    if (context.hasFieldNames() && !context.fieldNames().isEmpty()) {
        FieldsVisitor nestedFieldsVisitor = null;
        if (loadAllStored) {
            nestedFieldsVisitor = new AllFieldsVisitor();
        } else if (fieldNames != null || fieldNamePatterns != null) {
            nestedFieldsVisitor = new CustomFieldsVisitor(fieldNames == null ? Collections.<String>emptySet() : fieldNames,
                    fieldNamePatterns == null ? Collections.<String>emptyList() : fieldNamePatterns, false);
        }

        if (nestedFieldsVisitor != null) {
            loadStoredFields(context, subReaderContext, nestedFieldsVisitor, nestedSubDocId);
            nestedFieldsVisitor.postProcess(context.mapperService());
            if (!nestedFieldsVisitor.fields().isEmpty()) {
                searchFields = new HashMap<>(nestedFieldsVisitor.fields().size());
                for (Map.Entry<String, List<Object>> entry : nestedFieldsVisitor.fields().entrySet()) {
                    searchFields.put(entry.getKey(), new InternalSearchHitField(entry.getKey(), entry.getValue()));
                }
            }
        }
    }
    return searchFields;
}
 

@Override
public void collect(int doc) {
    try {
        FieldsVisitor fieldsVisitor = new FieldsVisitor(false);
        context.reader().document(doc, fieldsVisitor);
        Uid uid = fieldsVisitor.uid();
        final long version = Versions.loadVersion(context.reader(), new Term(UidFieldMapper.NAME, uid.toBytesRef()));
        docsToPurge.add(new DocToPurge(uid.type(), uid.id(), version, fieldsVisitor.routing()));
    } catch (Exception e) {
        logger.trace("failed to collect doc", e);
    }
}
 

private void loadStoredFields(SearchContext searchContext, LeafReaderContext readerContext, FieldsVisitor fieldVisitor, int docId) {
    fieldVisitor.reset();
    try {
        readerContext.reader().document(docId, fieldVisitor);
    } catch (IOException e) {
        throw new FetchPhaseExecutionException(searchContext, "Failed to fetch doc id [" + docId + "]", e);
    }
}
 

private static FieldsVisitor buildFieldsVisitors(String[] fields, FetchSourceContext fetchSourceContext) {
    if (fields == null || fields.length == 0) {
        return fetchSourceContext.fetchSource() ? new FieldsVisitor(true) : null;
    }

    return new CustomFieldsVisitor(Sets.newHashSet(fields), fetchSourceContext.fetchSource());
}