text: /**
   *    Copyright (C) 2019-present MongoDB, Inc.
   *
   *    This program is free software: you can redistribute it and/or modify
   *    it under the terms of the Server Side Public License, version 1,
   *    as published by MongoDB, Inc.
   *
   *    This program is distributed in the hope that it will be useful,
   *    but WITHOUT ANY WARRANTY; without even the implied warranty of
   *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   *    Server Side Public License for more details.
   *
   *    You should have received a copy of the Server Side Public License
   *    along with this program. If not, see
   *    <http://www.mongodb.com/licensing/server-side-public-license>.
   *
   *    As a special exception, the copyright holders give permission to link the
   *    code of portions of this program with the OpenSSL library under certain
   *    conditions as described in each individual source file and distribute
   *    linked combinations including the program with the OpenSSL library. You
   *    must comply with the Server Side Public License in all respects for
   *    all of the code used other than as permitted herein. If you modify file(s)
   *    with this exception, you may extend this exception to your version of the
   *    file(s), but you are not obligated to do so. If you do not wish to do so,
   *    delete this exception statement from your version. If you delete this
   *    exception statement from all source files in the program, then also delete
   *    it in the license file.
   */
  
  #include "mongo/db/repl/oplog_entry_or_grouped_inserts.h"
  #include "mongo/bson/bsonobjbuilder.h"
  
  namespace mongo {
  namespace repl {
  BSONObj OplogEntryOrGroupedInserts::toBSON() const {
      if (!isGroupedInserts())
          return getOp().getEntry().toBSON();
  
      // Since we found more than one document, create grouped insert of many docs.
      // We are going to group many 'i' ops into one big 'i' op, with array fields for
      // 'ts', 't', and 'o', corresponding to each individual op.
      // For example:
      // { ts: Timestamp(1,1), t:1, ns: "test.foo", op:"i", o: {_id:1} }
      // { ts: Timestamp(1,2), t:1, ns: "test.foo", op:"i", o: {_id:2} }
      // become:
      // { ts: [Timestamp(1, 1), Timestamp(1, 2)],
      //    t: [1, 1],
      //    o: [{_id: 1}, {_id: 2}],
      //   ns: "test.foo",
      //   op: "i"
      // }
      // This BSONObj is used for error messages logging only.
      BSONObjBuilder groupedInsertBuilder;
      // Populate the "ts" field with an array of all the grouped inserts' timestamps.
      {
          BSONArrayBuilder tsArrayBuilder(groupedInsertBuilder.subarrayStart("ts"));
          for (auto op : _entryOrGroupedInserts) {
              tsArrayBuilder.append(op->getTimestamp());
          }
      }
      // Populate the "t" (term) field with an array of all the grouped inserts' terms.
      {
          BSONArrayBuilder tArrayBuilder(groupedInsertBuilder.subarrayStart("t"));
          for (auto op : _entryOrGroupedInserts) {
              long long term = OpTime::kUninitializedTerm;
              auto parsedTerm = op->getTerm();
              if (parsedTerm)
                  term = parsedTerm.get();
              tArrayBuilder.append(term);
          }
      }
      // Populate the "o" field with an array of all the grouped inserts.
      {
          BSONArrayBuilder oArrayBuilder(groupedInsertBuilder.subarrayStart("o"));
          for (auto op : _entryOrGroupedInserts) {
              oArrayBuilder.append(op->getObject());
          }
      }
      // Generate an op object of all elements except for "ts", "t", and "o", since we
      // need to make those fields arrays of all the ts's, t's, and o's.
      groupedInsertBuilder.appendElementsUnique(getOp().getEntry().toBSON());
      return groupedInsertBuilder.obj();
  }
  }  // namespace repl
  }  // namespace mongo
  