depends/libhdfs3/src/client/PeerCache.cpp

/********************************************************************
 * 2014 -
 * open source under Apache License Version 2.0
 ********************************************************************/
/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 */
#include <inttypes.h>

#include "client/PeerCache.h"

namespace Hdfs {
namespace Internal {

LruMap<std::string, PeerCache::value_type> PeerCache::Map;

PeerCache::PeerCache(const SessionConfig& conf)
    : cacheSize(conf.getSocketCacheCapacity()),
      expireTimeInterval(conf.getSocketCacheExpiry()) {
  Map.setMaxSize(cacheSize);
}

std::string PeerCache::buildKey(const DatanodeInfo& datanode) {
  std::stringstream ss;
  ss.imbue(std::locale::classic());
  ss << datanode.getIpAddr() << datanode.getXferPort()
     << datanode.getDatanodeId();
  return ss.str();
}

shared_ptr<Socket> PeerCache::getConnection(const DatanodeInfo& datanode) {
  std::string key = buildKey(datanode);
  value_type value;
  int64_t elipsed;

  if (!Map.findAndErase(key, &value)) {
    LOG(DEBUG1, "PeerCache miss for datanode %s uuid(%s).",
        datanode.formatAddress().c_str(), datanode.getDatanodeId().c_str());
    return shared_ptr<Socket>();
  } else if ((elipsed = ToMilliSeconds(value.second, steady_clock::now())) >
             expireTimeInterval) {
    LOG(DEBUG1, "PeerCache expire for datanode %s uuid(%s).",
        datanode.formatAddress().c_str(), datanode.getDatanodeId().c_str());
    return shared_ptr<Socket>();
  }

  LOG(DEBUG1, "PeerCache hit for datanode %s uuid(%s), elipsed %" PRId64,
      datanode.formatAddress().c_str(), datanode.getDatanodeId().c_str(),
      elipsed);
  return value.first;
}

void PeerCache::addConnection(shared_ptr<Socket> peer,
                              const DatanodeInfo& datanode) {
  std::string key = buildKey(datanode);
  value_type value(peer, steady_clock::now());
  Map.insert(key, value);
  LOG(DEBUG1, "PeerCache add for datanode %s uuid(%s).",
      datanode.formatAddress().c_str(), datanode.getDatanodeId().c_str());
}
}
}