text: /**
   *    Copyright (C) 2015 MongoDB Inc.
   *
   *    This program is free software: you can redistribute it and/or  modify
   *    it under the terms of the GNU Affero General Public License, version 3,
   *    as published by the Free Software Foundation.
   *
   *    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
   *    GNU Affero General Public License for more details.
   *
   *    You should have received a copy of the GNU Affero General Public License
   *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
   *
   *    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 GNU Affero General 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.
   */
  
  #define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kQuery
  
  #include "mongo/platform/basic.h"
  
  #include "mongo/db/query/getmore_request.h"
  
  #include <boost/optional.hpp>
  
  #include "mongo/db/command_generic_argument.h"
  #include "mongo/db/commands.h"
  #include "mongo/db/namespace_string.h"
  #include "mongo/db/repl/bson_extract_optime.h"
  #include "mongo/util/assert_util.h"
  #include "mongo/util/stringutils.h"
  
  namespace mongo {
  
  namespace {
  
  const char kCollectionField[] = "collection";
  const char kBatchSizeField[] = "batchSize";
  const char kAwaitDataTimeoutField[] = "maxTimeMS";
  const char kTermField[] = "term";
  const char kLastKnownCommittedOpTimeField[] = "lastKnownCommittedOpTime";
  
  }  // namespace
  
  const char GetMoreRequest::kGetMoreCommandName[] = "getMore";
  
  GetMoreRequest::GetMoreRequest() : cursorid(0), batchSize(0) {}
  
  GetMoreRequest::GetMoreRequest(NamespaceString namespaceString,
                                 CursorId id,
                                 boost::optional<std::int64_t> sizeOfBatch,
                                 boost::optional<Milliseconds> awaitDataTimeout,
                                 boost::optional<long long> term,
                                 boost::optional<repl::OpTime> lastKnownCommittedOpTime)
      : nss(std::move(namespaceString)),
        cursorid(id),
        batchSize(sizeOfBatch),
        awaitDataTimeout(awaitDataTimeout),
        term(term),
        lastKnownCommittedOpTime(lastKnownCommittedOpTime) {}
  
  Status GetMoreRequest::isValid() const {
      if (!nss.isValid()) {
          return Status(ErrorCodes::InvalidNamespace,
                        str::stream() << "Invalid namespace for getMore: " << nss.ns());
      }
  
      if (cursorid == 0) {
          return Status(ErrorCodes::BadValue, "Cursor id for getMore must be non-zero");
      }
  
      if (batchSize && *batchSize <= 0) {
          return Status(ErrorCodes::BadValue,
                        str::stream() << "Batch size for getMore must be positive, "
                                      << "but received: "
                                      << *batchSize);
      }
  
      return Status::OK();
  }
  
  // static
  StatusWith<GetMoreRequest> GetMoreRequest::parseFromBSON(const std::string& dbname,
                                                           const BSONObj& cmdObj) {
      // Required fields.
      boost::optional<CursorId> cursorid;
      boost::optional<NamespaceString> nss;
  
      // Optional fields.
      boost::optional<std::int64_t> batchSize;
      boost::optional<Milliseconds> awaitDataTimeout;
      boost::optional<long long> term;
      boost::optional<repl::OpTime> lastKnownCommittedOpTime;
  
      for (BSONElement el : cmdObj) {
          const auto fieldName = el.fieldNameStringData();
          if (fieldName == kGetMoreCommandName) {
              if (el.type() != BSONType::NumberLong) {
                  return {ErrorCodes::TypeMismatch,
                          str::stream() << "Field 'getMore' must be of type long in: " << cmdObj};
              }
  
              cursorid = el.Long();
          } else if (fieldName == kCollectionField) {
              if (el.type() != BSONType::String) {
                  return {ErrorCodes::TypeMismatch,
                          str::stream() << "Field 'collection' must be of type string in: "
                                        << cmdObj};
              }
  
              BSONElement collElt = cmdObj["collection"];
              const std::string coll = (collElt.type() == BSONType::String) ? collElt.String() : "";
              nss = NamespaceString(dbname, coll);
          } else if (fieldName == kBatchSizeField) {
              if (!el.isNumber()) {
                  return {ErrorCodes::TypeMismatch,
                          str::stream() << "Field 'batchSize' must be a number in: " << cmdObj};
              }
  
              batchSize = el.numberLong();
          } else if (fieldName == kAwaitDataTimeoutField) {
              auto maxAwaitDataTime = QueryRequest::parseMaxTimeMS(el);
              if (!maxAwaitDataTime.isOK()) {
                  return maxAwaitDataTime.getStatus();
              }
  
              if (maxAwaitDataTime.getValue()) {
                  awaitDataTimeout = Milliseconds(maxAwaitDataTime.getValue());
              }
          } else if (fieldName == kTermField) {
              if (el.type() != BSONType::NumberLong) {
                  return {ErrorCodes::TypeMismatch,
                          str::stream() << "Field 'term' must be of type NumberLong in: " << cmdObj};
              }
              term = el.Long();
          } else if (fieldName == kLastKnownCommittedOpTimeField) {
              repl::OpTime ot;
              Status status = bsonExtractOpTimeField(el.wrap(), kLastKnownCommittedOpTimeField, &ot);
              if (!status.isOK()) {
                  return status;
              }
              lastKnownCommittedOpTime = ot;
          } else if (!isGenericArgument(fieldName)) {
              return {ErrorCodes::FailedToParse,
                      str::stream() << "Failed to parse: " << cmdObj << ". "
                                    << "Unrecognized field '"
                                    << fieldName
                                    << "'."};
          }
      }
  
      if (!cursorid) {
          return {ErrorCodes::FailedToParse,
                  str::stream() << "Field 'getMore' missing in: " << cmdObj};
      }
  
      if (!nss) {
          return {ErrorCodes::FailedToParse,
                  str::stream() << "Field 'collection' missing in: " << cmdObj};
      }
  
      GetMoreRequest request(
          std::move(*nss), *cursorid, batchSize, awaitDataTimeout, term, lastKnownCommittedOpTime);
      Status validStatus = request.isValid();
      if (!validStatus.isOK()) {
          return validStatus;
      }
  
      return request;
  }
  
  BSONObj GetMoreRequest::toBSON() const {
      BSONObjBuilder builder;
  
      builder.append(kGetMoreCommandName, cursorid);
      builder.append(kCollectionField, nss.coll());
  
      if (batchSize) {
          builder.append(kBatchSizeField, *batchSize);
      }
  
      if (awaitDataTimeout) {
          builder.append(kAwaitDataTimeoutField, durationCount<Milliseconds>(*awaitDataTimeout));
      }
  
      if (term) {
          builder.append(kTermField, *term);
      }
  
      if (lastKnownCommittedOpTime) {
          lastKnownCommittedOpTime->append(&builder, kLastKnownCommittedOpTimeField);
      }
  
      return builder.obj();
  }
  
  }  // namespace mongo
  