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/*
* Copyright (c) 2017 Cisco and/or its affiliates.
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef __VOM_INST_DB_H__
#define __VOM_INST_DB_H__
#include <map>
#include <memory>
#include <ostream>
#include "vom/logger.hpp"
namespace VOM {
/**
* A Database to store the unique 'singular' instances of a single object
* type.
* The instances are stored as weak pointers. So the DB does not own these
* objects, they are owned by object in the client_db.
*/
template <typename KEY, typename OBJ>
class singular_db
{
public:
/**
* Constructor
*/
singular_db() {}
/**
* Iterator
*/
typedef
typename std::map<KEY, std::weak_ptr<OBJ>>::const_iterator const_iterator;
/**
* Get iterator to the beginning of the DB
*/
const_iterator begin() const { return m_map.cbegin(); }
/**
* Get iterator to the beginning of the DB
*/
const_iterator end() const { return m_map.cend(); }
/**
* Find or add the object to the store.
* The object passed is deisred state. A new instance will be copy
* constructed from it. This function is templatised on the object type
* passed, which may be drrived from, the object type stored. this
* prevents slicing during the make_shared construction.
*/
template <typename DERIVED>
std::shared_ptr<OBJ> find_or_add(const KEY& key, const DERIVED& obj)
{
auto search = m_map.find(key);
if (search == m_map.end()) {
std::shared_ptr<OBJ> sp = std::make_shared<DERIVED>(obj);
m_map[key] = sp;
VOM_LOG(log_level_t::DEBUG) << *sp;
return (sp);
}
return (search->second.lock());
}
/**
* Find the object to the store.
*/
std::shared_ptr<OBJ> find(const KEY& key)
{
auto search = m_map.find(key);
if (search == m_map.end()) {
std::shared_ptr<OBJ> sp(NULL);
return (sp);
}
return (search->second.lock());
}
/**
* Release the object from the DB store, if it's the one we have stored
*/
void release(const KEY& key, const OBJ* obj)
{
auto search = m_map.find(key);
if (search != m_map.end()) {
if (search->second.expired()) {
m_map.erase(key);
} else {
std::shared_ptr<OBJ> sp = m_map[key].lock();
if (sp.get() == obj) {
m_map.erase(key);
}
}
}
}
/**
* Find the object to the store.
*/
void add(const KEY& key, std::shared_ptr<OBJ> sp) { m_map[key] = sp; }
/**
* Populate VPP from current state, on VPP restart
*/
void replay()
{
for (auto entry : m_map) {
entry.second.lock()->replay();
}
}
private:
/**
* the map of objects against their key
*/
std::map<const KEY, std::weak_ptr<OBJ>> m_map;
};
};
/*
* fd.io coding-style-patch-verification: ON
*
* Local Variables:
* eval: (c-set-style "mozilla")
* End:
*/
#endif
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