exclude.cpp

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/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
#include "exclude.hpp"
#include "encoding/block-helpers.hpp"

#include <boost/range/adaptors.hpp>

namespace ndn {

BOOST_CONCEPT_ASSERT((boost::EqualityComparable<Exclude>));
BOOST_CONCEPT_ASSERT((WireEncodable<Exclude>));
BOOST_CONCEPT_ASSERT((WireEncodableWithEncodingBuffer<Exclude>));
BOOST_CONCEPT_ASSERT((WireDecodable<Exclude>));
static_assert(std::is_base_of<tlv::Error, Exclude::Error>::value,
              "Exclude::Error must inherit from tlv::Error");

Exclude::Exclude()
{
}

Exclude::Exclude(const Block& wire)
{
  wireDecode(wire);
}

template<encoding::Tag TAG>
size_t
Exclude::wireEncode(EncodingImpl<TAG>& encoder) const
{
  if (m_exclude.empty()) {
    BOOST_THROW_EXCEPTION(Error("Exclude filter cannot be empty"));
  }

  size_t totalLength = 0;

  // Exclude ::= EXCLUDE-TYPE TLV-LENGTH Any? (NameComponent (Any)?)+
  // Any     ::= ANY-TYPE TLV-LENGTH(=0)

  for (const auto& item : m_exclude) {
    if (item.second) {
      totalLength += prependEmptyBlock(encoder, tlv::Any);
    }
    if (!item.first.empty() || !item.second) {
      totalLength += item.first.wireEncode(encoder);
    }
  }

  totalLength += encoder.prependVarNumber(totalLength);
  totalLength += encoder.prependVarNumber(tlv::Exclude);
  return totalLength;
}

template size_t
Exclude::wireEncode<encoding::EncoderTag>(EncodingImpl<encoding::EncoderTag>& encoder) const;

template size_t
Exclude::wireEncode<encoding::EstimatorTag>(EncodingImpl<encoding::EstimatorTag>& encoder) const;

const Block&
Exclude::wireEncode() const
{
  if (m_wire.hasWire())
    return m_wire;

  EncodingEstimator estimator;
  size_t estimatedSize = wireEncode(estimator);

  EncodingBuffer buffer(estimatedSize, 0);
  wireEncode(buffer);

  m_wire = buffer.block();
  return m_wire;
}

void
Exclude::wireDecode(const Block& wire)
{
  clear();

  if (wire.type() != tlv::Exclude)
    BOOST_THROW_EXCEPTION(tlv::Error("Unexpected TLV type when decoding Exclude"));

  m_wire = wire;
  m_wire.parse();

  if (m_wire.elements_size() == 0) {
    BOOST_THROW_EXCEPTION(Error("Exclude element cannot be empty"));
  }

  // Exclude ::= EXCLUDE-TYPE TLV-LENGTH Any? (NameComponent (Any)?)+
  // Any     ::= ANY-TYPE TLV-LENGTH(=0)

  Block::element_const_iterator i = m_wire.elements_begin();
  if (i->type() == tlv::Any) {
    appendExclude(name::Component(), true);
    ++i;
  }

  while (i != m_wire.elements_end()) {
    name::Component excludedComponent;
    try {
      excludedComponent = std::move(name::Component(*i));
    }
    catch (const name::Component::Error&) {
      BOOST_THROW_EXCEPTION(Error("Incorrect format of Exclude filter"));
    }

    ++i;

    if (i != m_wire.elements_end()) {
      if (i->type() == tlv::Any) {
        appendExclude(excludedComponent, true);
        ++i;
      }
      else {
        appendExclude(excludedComponent, false);
      }
    }
    else {
      appendExclude(excludedComponent, false);
    }
  }
}

// example: ANY /b /d ANY /f
//
// ordered in map as:
//
// /f (false); /d (true); /b (false); / (true)
//
// lower_bound(/)  -> / (true) <-- excluded (equal)
// lower_bound(/a) -> / (true) <-- excluded (any)
// lower_bound(/b) -> /b (false) <--- excluded (equal)
// lower_bound(/c) -> /b (false) <--- not excluded (not equal and no ANY)
// lower_bound(/d) -> /d (true) <- excluded
// lower_bound(/e) -> /d (true) <- excluded
bool
Exclude::isExcluded(const name::Component& comp) const
{
  const_iterator lowerBound = m_exclude.lower_bound(comp);
  if (lowerBound == end())
    return false;

  if (lowerBound->second)
    return true;
  else
    return lowerBound->first == comp;
}

Exclude&
Exclude::excludeOne(const name::Component& comp)
{
  if (!isExcluded(comp)) {
    m_exclude.insert(std::make_pair(comp, false));
    m_wire.reset();
  }
  return *this;
}

// example: ANY /b0 /d0 ANY /f0
//
// ordered in map as:
//
// /f0 (false); /d0 (true); /b0 (false); / (true)
//
// lower_bound(/)  -> / (true) <-- excluded (equal)
// lower_bound(/a0) -> / (true) <-- excluded (any)
// lower_bound(/b0) -> /b0 (false) <--- excluded (equal)
// lower_bound(/c0) -> /b0 (false) <--- not excluded (not equal and no ANY)
// lower_bound(/d0) -> /d0 (true) <- excluded
// lower_bound(/e0) -> /d0 (true) <- excluded


// examples with desired outcomes
// excludeRange(/, /f0) ->  ANY /f0
//                          /f0 (false); / (true)
// excludeRange(/, /f1) ->  ANY /f1
//                          /f1 (false); / (true)
// excludeRange(/a0, /e0) ->  ANY /f0
//                          /f0 (false); / (true)
// excludeRange(/a0, /e0) ->  ANY /f0
//                          /f0 (false); / (true)

// excludeRange(/b1, /c0) ->  ANY /b0 /b1 ANY /c0 /d0 ANY /f0
//                          /f0 (false); /d0 (true); /c0 (false); /b1 (true); /b0 (false); / (true)

Exclude&
Exclude::excludeRange(const name::Component& from, const name::Component& to)
{
  if (from >= to) {
    BOOST_THROW_EXCEPTION(Error("Invalid exclude range [" + from.toUri() + ", " + to.toUri() + "] "
                                "(for single name exclude use Exclude::excludeOne)"));
  }

  iterator newFrom = m_exclude.lower_bound(from);
  if (newFrom == end() || !newFrom->second /*without ANY*/) {
    std::pair<iterator, bool> fromResult = m_exclude.insert(std::make_pair(from, true));
    newFrom = fromResult.first;
    if (!fromResult.second) {
      // this means that the lower bound is equal to the item itself. So, just update ANY flag
      newFrom->second = true;
    }
  }
  // else
  // nothing special if start of the range already exists with ANY flag set

  iterator newTo = m_exclude.lower_bound(to); // !newTo cannot be end()
  if (newTo == newFrom || !newTo->second) {
    std::pair<iterator, bool> toResult = m_exclude.insert(std::make_pair(to, false));
    newTo = toResult.first;
    ++ newTo;
  }
  // else
  // nothing to do really

  m_exclude.erase(newTo, newFrom); // remove any intermediate node, since all of the are excluded

  m_wire.reset();
  return *this;
}

Exclude&
Exclude::excludeAfter(const name::Component& from)
{
  iterator newFrom = m_exclude.lower_bound(from);
  if (newFrom == end() || !newFrom->second /*without ANY*/) {
    std::pair<iterator, bool> fromResult = m_exclude.insert(std::make_pair(from, true));
    newFrom = fromResult.first;
    if (!fromResult.second) {
      // this means that the lower bound is equal to the item itself. So, just update ANY flag
      newFrom->second = true;
    }
  }
  // else
  // nothing special if start of the range already exists with ANY flag set

  if (newFrom != m_exclude.begin()) {
    // remove any intermediate node, since all of the are excluded
    m_exclude.erase(m_exclude.begin(), newFrom);
  }

  m_wire.reset();
  return *this;
}

std::ostream&
operator<<(std::ostream& os, const Exclude& exclude)
{
  bool isFirst = true;
  for (const auto& item : exclude | boost::adaptors::reversed) {
    if (!item.first.empty() || !item.second) {
      if (!isFirst)
        os << ",";
      os << item.first.toUri();
      isFirst = false;
    }
    if (item.second) {
      if (!isFirst)
        os << ",";
      os << "*";
      isFirst = false;
    }
  }
  return os;
}

std::string
Exclude::toUri() const
{
  std::ostringstream os;
  os << *this;
  return os.str();
}

bool
Exclude::operator==(const Exclude& other) const
{
  if (empty() && other.empty())
    return true;
  if (empty() || other.empty())
    return false;

  return wireEncode() == other.wireEncode();
}

} // namespace ndn