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/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
* Copyright (c) 2013-2018 Regents of the University of California.
*
* This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
*
* ndn-cxx library is free software: you can redistribute it and/or modify it under the
* terms of the GNU Lesser General Public License as published by the Free Software
* Foundation, either version 3 of the License, or (at your option) any later version.
*
* ndn-cxx library 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 Lesser General Public License for more details.
*
* You should have received copies of the GNU General Public License and GNU Lesser
* General Public License along with ndn-cxx, e.g., in COPYING.md file. If not, see
* <http://www.gnu.org/licenses/>.
*
* See AUTHORS.md for complete list of ndn-cxx authors and contributors.
*/
#ifndef NDN_META_INFO_HPP
#define NDN_META_INFO_HPP
#include "encoding/block.hpp"
#include "encoding/encoding-buffer.hpp"
#include "name-component.hpp"
#include "util/time.hpp"
#include <list>
namespace ndn {
const time::milliseconds DEFAULT_FRESHNESS_PERIOD = time::milliseconds::zero();
/**
* A MetaInfo holds the meta info which is signed inside the data packet.
*
* The class allows experimentation with application-defined meta information blocks,
* which slightly violates NDN-TLV specification. When using the application-defined
* meta information blocks be aware that this may result in packet drop (NFD and
* previous versions of ndn-cxx will gracefully accept such packet).
*
* The following definition of MetaInfo block is assumed in this implementation (compared
* to the NDN-TLV spec, definition extended to allow optional AppMetaInfo TLV blocks):
*
* MetaInfo ::= META-INFO-TYPE TLV-LENGTH
* ContentType?
* FreshnessPeriod?
* FinalBlockId?
* AppMetaInfo*
*
* AppMetaInfo ::= any TLV block with type in the restricted application range [128, 252]
*
* Note that AppMetaInfo blocks are application-defined and must have TLV type from
* the restricted application range [128, 252].
*/
class MetaInfo
{
public:
class Error : public tlv::Error
{
public:
using tlv::Error::Error;
};
MetaInfo();
/**
* @brief Create from wire encoding
*/
explicit
MetaInfo(const Block& block);
template<encoding::Tag TAG>
size_t
wireEncode(EncodingImpl<TAG>& encoder) const;
const Block&
wireEncode() const;
void
wireDecode(const Block& wire);
public: // getter/setter
/** @brief return ContentType
*
* If ContentType element is omitted, returns \c tlv::ContentType_Blob.
*/
uint32_t
getType() const
{
return m_type;
}
/** @brief set ContentType
* @param type a number defined in \c tlv::ContentTypeValue
*/
MetaInfo&
setType(uint32_t type);
/** @brief return FreshnessPeriod
*
* If FreshnessPeriod element is omitted, returns \c DEFAULT_FRESHNESS_PERIOD.
*/
time::milliseconds
getFreshnessPeriod() const
{
return m_freshnessPeriod;
}
/** @brief set FreshnessPeriod
* @throw std::invalid_argument specified FreshnessPeriod is negative
*/
MetaInfo&
setFreshnessPeriod(time::milliseconds freshnessPeriod);
/** @brief return FinalBlockId
*/
const optional<name::Component>&
getFinalBlock() const
{
return m_finalBlockId;
}
/** @brief set FinalBlockId
*/
MetaInfo&
setFinalBlock(optional<name::Component> finalBlockId);
public: // app-defined MetaInfo items
/**
* @brief Get all app-defined MetaInfo items
*
* @note Warning: Experimental API, which may change or disappear in the future
*
* @note If MetaInfo is decoded from wire and setType, setFreshnessPeriod, or setFinalBlock
* is called before *AppMetaInfo, all app-defined blocks will be lost
*/
const std::list<Block>&
getAppMetaInfo() const;
/**
* @brief Set app-defined MetaInfo items
*
* This method will replace all existing app-defined MetaInfo items, if they existed.
*
* @throw Error if some block in @p info has type not in the application range
* (http://named-data.net/doc/ndn-tlv/types.html)
*
* @note Warning: Experimental API, which may change or disappear in the future
*
* @note If MetaInfo is decoded from wire and setType, setFreshnessPeriod, or setFinalBlock
* is called before *AppMetaInfo, all app-defined blocks will be lost
*/
MetaInfo&
setAppMetaInfo(const std::list<Block>& info);
/**
* @brief Add an app-defined MetaInfo item
*
* @throw Error if @p block has type not in the application range
* (http://named-data.net/doc/ndn-tlv/types.html)
*
* @note Warning: Experimental API, which may change or disappear in the future
*
* @note If MetaInfo is decoded from wire and setType, setFreshnessPeriod, or setFinalBlock
* is called before *AppMetaInfo, all app-defined blocks will be lost
*/
MetaInfo&
addAppMetaInfo(const Block& block);
/**
* @brief Remove a first app-defined MetaInfo item with type @p tlvType
*
* @return true if an item was deleted
*
* @note Warning: Experimental API, which may change or disappear in the future
*
* @note If MetaInfo is decoded from wire and setType, setFreshnessPeriod, or setFinalBlock
* is called before *AppMetaInfo, all app-defined blocks will be lost
*/
bool
removeAppMetaInfo(uint32_t tlvType);
/**
* @brief Find a first app-defined MetaInfo item of type @p tlvType
*
* @return NULL if an item is not found, otherwise const pointer to the item
*
* @throw Error if @p tlvType is not in the application range
* (http://named-data.net/doc/ndn-tlv/types.html)
*
* @note Warning: Experimental API, which may change or disappear in the future
*
* @note If MetaInfo is decoded from wire and setType, setFreshnessPeriod, or setFinalBlock
* is called before *AppMetaInfo, all app-defined blocks will be lost
*/
const Block*
findAppMetaInfo(uint32_t tlvType) const;
public: // EqualityComparable concept
bool
operator==(const MetaInfo& other) const;
bool
operator!=(const MetaInfo& other) const;
private:
uint32_t m_type;
time::milliseconds m_freshnessPeriod;
optional<name::Component> m_finalBlockId;
std::list<Block> m_appMetaInfo;
mutable Block m_wire;
};
NDN_CXX_DECLARE_WIRE_ENCODE_INSTANTIATIONS(MetaInfo);
std::ostream&
operator<<(std::ostream& os, const MetaInfo& info);
inline bool
MetaInfo::operator==(const MetaInfo& other) const
{
return wireEncode() == other.wireEncode();
}
inline bool
MetaInfo::operator!=(const MetaInfo& other) const
{
return !(*this == other);
}
} // namespace ndn
#endif // NDN_META_INFO_HPP