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/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/**
* Copyright (c) 2013-2015 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_LINK_HPP
#define NDN_LINK_HPP
#include "data.hpp"
#include <set>
namespace ndn {
const size_t INVALID_SELECTED_DELEGATION_INDEX = std::numeric_limits<size_t>::max();
/** @brief represents a Link instance
*/
class Link : public Data
{
public:
class Error : public Data::Error
{
public:
explicit
Error(const std::string& what)
: Data::Error(what)
{
}
};
// The ordering is based on the preference number and needs to be preserved
typedef std::set<std::pair<uint32_t, Name>> DelegationSet;
/**
* @brief Create an empty Link object
*
* Note that in certain contexts that use Link::shared_from_this(), Link must be
* created using `make_shared`:
*
* shared_ptr<Link> linkObject = make_shared<Link>();
*
* Otherwise, Link::shared_from_this() will throw std::bad_weak_ptr.
*/
Link() = default;
/**
* @brief Create a Link object from a Block
*
* Note that in certain contexts that use Link::shared_from_this(), Link must be
* created using `make_shared`:
*
* shared_ptr<Link> linkObject = make_shared<Link>(block);
*
* Otherwise, Link::shared_from_this() will throw std::bad_weak_ptr.
*/
explicit
Link(const Block& block);
/**
* @brief Create a Link object with the given name
*
* @param name A reference to the name of the redirected namespace
*
* Note that in certain contexts that use Link::shared_from_this(), Link must be
* created using `make_shared`:
*
* shared_ptr<Link> link = make_shared<Link>(name);
*
* Otherwise, Link::shared_from_this() will throw std::bad_weak_ptr.
*/
explicit
Link(const Name& name);
/**
* @brief Create a Link object with the given name and pairs of <Preference, Name>
*
* @param name A reference to the name of the redirected namespace
* @param links A reference to the list of pairs of the redirected namespace
* along with its priority
*
* Note that in certain contexts that use Link::shared_from_this(), Link must be
* created using `make_shared`:
*
* shared_ptr<Link> link = make_shared<Link>(name, links);
*
* Otherwise, Link::shared_from_this() will throw std::bad_weak_ptr.
*/
Link(const Name& name, std::initializer_list<std::pair<uint32_t, Name>> links);
/**
* @brief Add a delegation in the format of <Name, Preference>
* @param preference The preference of the delegation to be added
* @param name The name of the delegation to be added
* @note If a delegation with @p name exists, its preference will be updated
*/
void
addDelegation(uint32_t preference, const Name& name);
/**
* @brief Remove a delegation whose name is @p name
* @param name The name of the delegation to be removed
* @return true if delegation is removed, otherwise false
*/
bool
removeDelegation(const Name& name);
/**
* @brief Get the pairs of <Name, Preference>
* @return a set of delegations
*/
const DelegationSet&
getDelegations() const;
/**
* @brief Decode from the wire format
* @warning This method does not preserve the relative order between delegations.
* To get a delegation by index, use \p getDelegationFromWire method.
*/
void
wireDecode(const Block& wire);
/** @brief gets the delegation at \p index from \p block
* @param block wire format of a Link object
* @param index 0-based index of a delegation in the Link object
* @return delegation preference and name
* @throw std::out_of_range index is out of range
*/
static std::tuple<uint32_t, Name>
getDelegationFromWire(const Block& block, size_t index);
/** @brief finds index of a delegation with \p delegationName from \p block
* @param block wire format of a Link object
* @return 0-based index of the first delegation with \p delegationName ,
* or -1 if no such delegation exists
*/
static ssize_t
findDelegationFromWire(const Block& block, const Name& delegationName);
static ssize_t
countDelegationsFromWire(const Block& block);
protected:
/** @brief prepend Link object as a Content block to the encoder
*
* The outermost Content element is not part of Link object structure.
*/
template<encoding::Tag TAG>
size_t
encodeContent(EncodingImpl<TAG>& encoder) const;
void
encodeContent();
void
decodeContent();
private:
bool
removeDelegationNoEncode(const Name& name);
private:
DelegationSet m_delegations;
};
} // namespace ndn
#endif // NDN_LINK_HPP