pit.cpp

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/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
#include "pit.hpp"
#include <type_traits>

#include <boost/concept/assert.hpp>
#include <boost/concept_check.hpp>
#include <type_traits>

namespace nfd {
namespace pit {

#if HAVE_IS_MOVE_CONSTRUCTIBLE
static_assert(std::is_move_constructible<DataMatchResult>::value,
              "DataMatchResult must be MoveConstructible");
#endif // HAVE_IS_MOVE_CONSTRUCTIBLE

} // namespace pit

// http://en.cppreference.com/w/cpp/concept/ForwardIterator
BOOST_CONCEPT_ASSERT((boost::ForwardIterator<Pit::const_iterator>));
// boost::ForwardIterator follows SGI standard http://www.sgi.com/tech/stl/ForwardIterator.html,
// which doesn't require DefaultConstructible
#ifdef HAVE_IS_DEFAULT_CONSTRUCTIBLE
static_assert(std::is_default_constructible<Pit::const_iterator>::value,
              "Pit::const_iterator must be default-constructible");
#else
BOOST_CONCEPT_ASSERT((boost::DefaultConstructible<Pit::const_iterator>));
#endif // HAVE_IS_DEFAULT_CONSTRUCTIBLE

Pit::Pit(NameTree& nameTree)
  : m_nameTree(nameTree)
  , m_nItems(0)
{
}

std::pair<shared_ptr<pit::Entry>, bool>
Pit::findOrInsert(const Interest& interest, bool allowInsert)
{
  // ensure NameTree entry exists
  const Name& name = interest.getName();
  bool isEndWithDigest = name.size() > 0 && name[-1].isImplicitSha256Digest();
  shared_ptr<name_tree::Entry> nte = m_nameTree.lookup(isEndWithDigest ? name.getPrefix(-1) : name);
  BOOST_ASSERT(nte != nullptr);
  size_t nteNameLen = nte->getPrefix().size();

  // check if PIT entry already exists
  const std::vector<shared_ptr<pit::Entry>>& pitEntries = nte->getPitEntries();
  auto it = std::find_if(pitEntries.begin(), pitEntries.end(),
    [&interest, nteNameLen] (const shared_ptr<pit::Entry>& entry) -> bool {
      // initial part of the name is guaranteed to be the same
      BOOST_ASSERT(entry->getInterest().getName().compare(0, nteNameLen,
                   interest.getName(), 0, nteNameLen) == 0);
      // compare implicit digest (or its absence) only
      return entry->getInterest().getName().compare(nteNameLen, Name::npos,
                                                    interest.getName(), nteNameLen) == 0 &&
             entry->getInterest().getSelectors() == interest.getSelectors();
    });
  if (it != pitEntries.end()) {
    return {*it, false};
  }

  if (!allowInsert) {
    return {nullptr, true};
  }

  auto entry = make_shared<pit::Entry>(interest);
  nte->insertPitEntry(entry);
  m_nItems++;
  return {entry, true};
}

pit::DataMatchResult
Pit::findAllDataMatches(const Data& data) const
{
  auto&& ntMatches = m_nameTree.findAllMatches(data.getName(),
    [] (const name_tree::Entry& entry) { return entry.hasPitEntries(); });

  pit::DataMatchResult matches;
  for (const name_tree::Entry& nte : ntMatches) {
    for (const shared_ptr<pit::Entry>& pitEntry : nte.getPitEntries()) {
      if (pitEntry->getInterest().matchesData(data))
        matches.emplace_back(pitEntry);
    }
  }

  return matches;
}

void
Pit::erase(shared_ptr<pit::Entry> pitEntry)
{
  shared_ptr<name_tree::Entry> nameTreeEntry = pitEntry->m_nameTreeEntry;
  BOOST_ASSERT(static_cast<bool>(nameTreeEntry));

  nameTreeEntry->erasePitEntry(pitEntry);
  m_nameTree.eraseEntryIfEmpty(nameTreeEntry);

  --m_nItems;
}

Pit::const_iterator
Pit::begin() const
{
  return const_iterator(m_nameTree.fullEnumerate(
    [] (const name_tree::Entry& entry) { return entry.hasPitEntries(); }).begin());
}

} // namespace nfd