hdfs-fs-cache.h

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// Copyright 2012 Cloudera Inc.
//
// 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 IMPALA_RUNTIME_HDFS_FS_CACHE_H
#define IMPALA_RUNTIME_HDFS_FS_CACHE_H

#include <string>
#include <boost/scoped_ptr.hpp>
#include <boost/unordered_map.hpp>
#include <boost/thread/mutex.hpp>
#include <hdfs.h>

#include "common/status.h"

namespace impala {

//
class HdfsFsCache {
 public:
  typedef boost::unordered_map<std::string, hdfsFS> HdfsFsMap;

  static HdfsFsCache* instance() { return HdfsFsCache::instance_.get(); }

  static void Init();

  Status GetLocalConnection(hdfsFS* fs);

  Status GetConnection(const std::string& path, hdfsFS* fs,
      HdfsFsMap* local_cache = NULL);

  static string GetNameNodeFromPath(const string& path, string* err);

 private:
  static boost::scoped_ptr<HdfsFsCache> instance_;

  boost::mutex lock_;  // protects fs_map_
  HdfsFsMap fs_map_;

  HdfsFsCache() { };
  HdfsFsCache(HdfsFsCache const& l); // disable copy ctor
  HdfsFsCache& operator=(HdfsFsCache const& l); // disable assignment
};

}

#endif