tools/mosesdecoder/moses/FF/VW/ThreadLocalByFeatureStorage.h

#pragma once

#include <string>
#include <cstdlib>
#include <vector>
#include <map>

#include <boost/thread/tss.hpp>
#include <boost/shared_ptr.hpp>

#include "moses/FF/FeatureFunction.h"

namespace Moses
{

template <class Value>
struct DefaultFactory {
  typedef boost::shared_ptr<Value> ValuePtr;

  ValuePtr operator()() {
    return ValuePtr(new Value());
  }
};

template<class Value, class Factory = DefaultFactory<Value> >
class ThreadLocalByFeatureStorage
{
public:
  typedef boost::shared_ptr<Value> ValuePtr;
  typedef std::map<std::string, ValuePtr> NameValueMap;
  typedef boost::thread_specific_ptr<NameValueMap> TSNameValueMap;

  ThreadLocalByFeatureStorage(FeatureFunction* ff,
                              Factory factory = Factory())
    : m_ff(ff), m_factory(factory) {}

  virtual ~ThreadLocalByFeatureStorage() {} // provide empty virtual dtor

  virtual ValuePtr GetStored() {
    if(!m_nameMap.get())
      m_nameMap.reset(new NameValueMap());

    typename NameValueMap::iterator it
    = m_nameMap->find(m_ff->GetScoreProducerDescription());

    if(it == m_nameMap->end()) {
      std::pair<typename NameValueMap::iterator, bool> ret;
      ret = m_nameMap->insert(
              std::make_pair(m_ff->GetScoreProducerDescription(), m_factory()));

      return ret.first->second;
    } else {
      return it->second;
    }
  }

  virtual const ValuePtr GetStored() const {
    UTIL_THROW_IF2(!m_nameMap.get(),
                   "No thread local storage has been created for: "
                   << m_ff->GetScoreProducerDescription());

    typename NameValueMap::const_iterator it
    = m_nameMap->find(m_ff->GetScoreProducerDescription());

    UTIL_THROW_IF2(it == m_nameMap->end(),
                   "No features stored for: "
                   << m_ff->GetScoreProducerDescription());

    return it->second;
  }

private:
  FeatureFunction* m_ff;
  Factory m_factory;
  static TSNameValueMap m_nameMap;
};

template <class Value, class Factory>
typename ThreadLocalByFeatureStorage<Value, Factory>::TSNameValueMap
ThreadLocalByFeatureStorage<Value, Factory>::m_nameMap;

}