composer.hpp

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/*
 * Copyright (c) 2014-2015, Hewlett-Packard Development Company, LP.
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
 * more details. You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 * HP designates this particular file as subject to the "Classpath" exception
 * as provided by HP in the LICENSE.txt file that accompanied this code.
 */
#ifndef FOEDUS_STORAGE_COMPOSER_HPP_
#define FOEDUS_STORAGE_COMPOSER_HPP_

#include <iosfwd>
#include <string>

#include "foedus/compiler.hpp"
#include "foedus/epoch.hpp"
#include "foedus/error_stack.hpp"
#include "foedus/fwd.hpp"
#include "foedus/cache/fwd.hpp"
#include "foedus/memory/aligned_memory.hpp"
#include "foedus/snapshot/fwd.hpp"
#include "foedus/snapshot/snapshot.hpp"
#include "foedus/snapshot/snapshot_id.hpp"
#include "foedus/storage/fwd.hpp"
#include "foedus/storage/storage_id.hpp"
#include "foedus/thread/thread_id.hpp"

namespace foedus {
namespace storage {
class Composer CXX11_FINAL {
 public:
  Composer(Engine *engine, StorageId storage_id);

  Engine*   get_engine() { return engine_; }
  StorageId get_storage_id() const { return storage_id_; }
  StorageType get_storage_type() const { return storage_type_; }

  struct ComposeArguments {
    snapshot::SnapshotWriter*         snapshot_writer_;
    cache::SnapshotFileSet*           previous_snapshot_files_;
    snapshot::SortedBuffer* const*    log_streams_;
    uint32_t                          log_streams_count_;
    memory::AlignedMemory*            work_memory_;
    Epoch                             base_epoch_;
    Page*                             root_info_page_;
  };
  ErrorStack  compose(const ComposeArguments& args);

  struct ConstructRootArguments {
    snapshot::SnapshotWriter*         snapshot_writer_;
    cache::SnapshotFileSet*           previous_snapshot_files_;
    const Page* const*                root_info_pages_;
    uint32_t                          root_info_pages_count_;
    snapshot::LogGleanerResource*     gleaner_resource_;
    SnapshotPagePointer*              new_root_page_pointer_;
  };

  ErrorStack  construct_root(const ConstructRootArguments& args);

  struct DropVolatilesArguments {
    snapshot::Snapshot            snapshot_;
    uint16_t                      my_partition_;
    bool                          partitioned_drop_;
    memory::PagePoolOffsetChunk*  dropped_chunks_;
    uint64_t*                     dropped_count_;

    void drop(Engine* engine, VolatilePagePointer pointer) const;
  };
  struct DropResult {
    explicit DropResult(const DropVolatilesArguments& args) {
      max_observed_ = args.snapshot_.valid_until_epoch_;  // min value to make store_max easier.
      dropped_all_ = true;  // "so far". zero-inspected, thus zero-failure.
    }
    inline void combine(const DropResult& other) {
      max_observed_.store_max(other.max_observed_);
      dropped_all_ &= other.dropped_all_;
    }

    inline void on_rec_observed(Epoch epoch) {
      if (epoch > max_observed_) {
        max_observed_ = epoch;
        dropped_all_ = false;
      }
    }

    friend std::ostream&    operator<<(std::ostream& o, const DropResult& v);

    Epoch max_observed_;
    bool  dropped_all_;
    bool  padding_[3];
  };

  DropResult drop_volatiles(const DropVolatilesArguments& args);

  void drop_root_volatile(const DropVolatilesArguments& args);

  friend std::ostream&    operator<<(std::ostream& o, const Composer& v);

 private:
  Engine* const                       engine_;
  const StorageId                     storage_id_;
  const StorageType                   storage_type_;
};

}  // namespace storage
}  // namespace foedus
#endif  // FOEDUS_STORAGE_COMPOSER_HPP_