C++ View::dataLen方法代码示例

void DBClientCursor::dataReceived(bool& retry, string& host) {
    // If this is a reply to our initial command request.
    if (_isCommand && cursorId == 0) {
        commandDataReceived();
        return;
    }

    QueryResult::View qr = batch.m.singleData().view2ptr();
    resultFlags = qr.getResultFlags();

    if (qr.getResultFlags() & ResultFlag_ErrSet) {
        wasError = true;
    }

    if (qr.getResultFlags() & ResultFlag_CursorNotFound) {
        // cursor id no longer valid at the server.
        invariant(qr.getCursorId() == 0);

        if (!(opts & QueryOption_CursorTailable)) {
            uasserted(13127,
                      str::stream() << "cursor id " << cursorId << " didn't exist on server.");
        }

        // 0 indicates no longer valid (dead)
        cursorId = 0;
    }

    if (cursorId == 0 || !(opts & QueryOption_CursorTailable)) {
        // only set initially: we don't want to kill it on end of data
        // if it's a tailable cursor
        cursorId = qr.getCursorId();
    }

    batch.nReturned = qr.getNReturned();
    batch.pos = 0;
    batch.data = qr.data();
    batch.remainingBytes = qr.dataLen();

    _client->checkResponse(batch.data, batch.nReturned, &retry, &host);  // watches for "not master"

    if (qr.getResultFlags() & ResultFlag_ShardConfigStale) {
        BSONObj error;
        verify(peekError(&error));
        throw RecvStaleConfigException(
            (string) "stale config on lazy receive" + causedBy(getErrField(error)), error);
    }

    /* this assert would fire the way we currently work:
        verify( nReturned || cursorId == 0 );
    */
}

LegacyReply::LegacyReply(const Message* message) {
    invariant(message->operation() == opReply);

    QueryResult::View qr = message->singleData().view2ptr();

    // should be checked by caller.
    invariant(qr.msgdata().getNetworkOp() == opReply);

    uassert(ErrorCodes::BadValue,
            str::stream() << "Got legacy command reply with a bad cursorId field,"
                          << " expected a value of 0 but got "
                          << qr.getCursorId(),
            qr.getCursorId() == 0);

    uassert(ErrorCodes::BadValue,
            str::stream() << "Got legacy command reply with a bad nReturned field,"
                          << " expected a value of 1 but got "
                          << qr.getNReturned(),
            qr.getNReturned() == 1);

    uassert(ErrorCodes::BadValue,
            str::stream() << "Got legacy command reply with a bad startingFrom field,"
                          << " expected a value of 0 but got "
                          << qr.getStartingFrom(),
            qr.getStartingFrom() == 0);

    auto status = Validator<BSONObj>::validateLoad(qr.data(), qr.dataLen());
    uassert(ErrorCodes::InvalidBSON,
            str::stream() << "Got legacy command reply with invalid BSON in the metadata field"
                          << causedBy(status),
            status.isOK());

    _commandReply = BSONObj(qr.data());
    _commandReply.shareOwnershipWith(message->sharedBuffer());

    if (_commandReply.firstElementFieldName() == "$err"_sd) {
        // Upconvert legacy errors.
        BSONObjBuilder bob;
        bob.appendAs(_commandReply.firstElement(), "errmsg");
        bob.append("ok", 0.0);
        if (auto code = _commandReply["code"]) {
            bob.append(code);
        }
        _commandReply = bob.obj();
    }

    return;
}

void DBClientCursor::commandDataReceived() {
    int op = batch.m.operation();
    invariant(op == opReply || op == dbCommandReply);

    batch.nReturned = 1;
    batch.pos = 0;

    auto commandReply = rpc::makeReply(&batch.m);

    auto commandStatus = getStatusFromCommandResult(commandReply->getCommandReply());

    if (ErrorCodes::SendStaleConfig == commandStatus) {
        throw RecvStaleConfigException("stale config in DBClientCursor::dataReceived()",
                                       commandReply->getCommandReply());
    } else if (!commandStatus.isOK()) {
        wasError = true;
    }

    if (_client->getReplyMetadataReader()) {
        uassertStatusOK(_client->getReplyMetadataReader()(commandReply->getMetadata(),
                                                          _client->getServerAddress()));
    }

    // HACK: If we got an OP_COMMANDREPLY, take the reply object
    // and shove it in to an OP_REPLY message.
    if (op == dbCommandReply) {
        // Need to take ownership here as we destroy the underlying message.
        BSONObj reply = commandReply->getCommandReply().getOwned();
        batch.m.reset();
        replyToQuery(0, batch.m, reply);
    }

    QueryResult::View qr = batch.m.singleData().view2ptr();
    batch.data = qr.data();
    batch.remainingBytes = qr.dataLen();
}