content: /*
   * The Alluxio Open Foundation licenses this work under the Apache License, version 2.0
   * (the "License"). You may not use this work except in compliance with the License, which is
   * available at www.apache.org/licenses/LICENSE-2.0
   *
   * This software is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
   * either express or implied, as more fully set forth in the License.
   *
   * See the NOTICE file distributed with this work for information regarding copyright ownership.
   */
  
  package alluxio.worker.block.meta;
  
  import alluxio.worker.block.BlockMetadataEvictorView;
  
  import com.google.common.base.Preconditions;
  
  import java.util.ArrayList;
  import java.util.HashSet;
  import java.util.List;
  import java.util.Set;
  
  /**
   * This class is a wrapper of {@link StorageDir} to provide more limited access for evictors.
   */
  public class StorageDirEvictorView extends StorageDirView {
    /** The {@link BlockMetadataEvictorView} this view is associated with. */
    private final BlockMetadataEvictorView mMetadataView;
  
    // The below data structures are used by the evictor to mark blocks to move in/out during
    // generating an eviction plan.
    private final Set<Long> mBlocksToMoveIn = new HashSet<>();
    private final Set<Long> mBlocksToMoveOut = new HashSet<>();
    private long mBlocksToMoveInSize = 0L;
    private long mBlocksToMoveOutSize = 0L;
  
    /**
     * Creates a {@link StorageDirEvictorView} using the actual {@link StorageDir}
     * and the associated {@link BlockMetadataEvictorView}.
     *
     * @param dir which the dirView is constructed from
     * @param tierView which the dirView is under
     * @param managerView which the dirView is associated with
     */
    public StorageDirEvictorView(StorageDir dir, StorageTierEvictorView tierView,
        BlockMetadataEvictorView managerView) {
      super(dir, tierView);
      mMetadataView = Preconditions.checkNotNull(managerView, "view");
    }
  
    @Override
    public long getAvailableBytes() {
      return mDir.getAvailableBytes() + mBlocksToMoveOutSize - mBlocksToMoveInSize;
    }
  
    /**
     * Gets a filtered list of block metadata, for blocks that are neither pinned or being blocked.
     *
     * @return a list of metadata for all evictable blocks
     */
    public List<BlockMeta> getEvictableBlocks() {
      List<BlockMeta> filteredList = new ArrayList<>();
  
      for (BlockMeta blockMeta : mDir.getBlocks()) {
        long blockId = blockMeta.getBlockId();
        if (mMetadataView.isBlockEvictable(blockId)) {
          filteredList.add(blockMeta);
        }
      }
      return filteredList;
    }
  
    /**
     * Gets evictable bytes for this dir, i.e., the total bytes of total evictable blocks.
     *
     * @return evictable bytes for this dir
     */
    public long getEvitableBytes() {
      long bytes = 0;
      for (BlockMeta blockMeta : mDir.getBlocks()) {
        long blockId = blockMeta.getBlockId();
        if (mMetadataView.isBlockEvictable(blockId)) {
          bytes += blockMeta.getBlockSize();
        }
      }
      return bytes;
    }
  
    /**
     * Clears all marks about blocks to move in/out in this view.
     */
    public void clearBlockMarks() {
      mBlocksToMoveIn.clear();
      mBlocksToMoveOut.clear();
      mBlocksToMoveInSize = mBlocksToMoveOutSize = 0L;
    }
  
    /**
     * Returns an indication whether the given block is marked to be moved out.
     *
     * @param blockId the block ID
     * @return whether the block is marked to be moved out
     */
    public boolean isMarkedToMoveOut(long blockId) {
      return mBlocksToMoveOut.contains(blockId);
    }
  
    /**
     * Marks a block to move into this dir view, which is used by the evictor.
     *
     * @param blockId the Id of the block
     * @param blockSize the block size
     */
    public void markBlockMoveIn(long blockId, long blockSize) {
      if (mBlocksToMoveIn.add(blockId)) {
        mBlocksToMoveInSize += blockSize;
      }
    }
  
    /**
     * Marks a block to move out of this dir view, which is used by the evictor.
     *
     * @param blockId the Id of the block
     * @param blockSize the block size
     */
    public void markBlockMoveOut(long blockId, long blockSize) {
      if (mBlocksToMoveOut.add(blockId)) {
        mBlocksToMoveOutSize += blockSize;
      }
    }
  }
  