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.client.file.cache.store;
  
  import alluxio.client.file.cache.CacheManagerOptions;
  import alluxio.client.file.cache.CacheStatus;
  import alluxio.client.file.cache.PageInfo;
  import alluxio.client.file.cache.PageStore;
  import alluxio.client.file.cache.evictor.CacheEvictor;
  import alluxio.client.file.cache.evictor.CacheEvictorOptions;
  import alluxio.util.io.FileUtils;
  
  import com.google.common.collect.ImmutableList;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.io.IOException;
  import java.nio.file.Files;
  import java.nio.file.Path;
  import java.util.List;
  import java.util.Optional;
  import java.util.function.Consumer;
  import java.util.stream.Stream;
  
  /**
   * Directory of page store.
   */
  public interface PageStoreDir extends CacheStatus {
    Logger LOG = LoggerFactory.getLogger(PageStoreDir.class);
  
    /**
     * Create a list of PageStoreDir based on the configuration.
     * @param options of cache manager
     * @return A list of LocalCacheDir
     * @throws IOException
     */
    static List<PageStoreDir> createPageStoreDirs(CacheManagerOptions options)
        throws IOException {
      return options.getPageStoreOptions().stream()
          .map(pageStoreOptions -> createPageStoreDir(options.getCacheEvictorOptions(),
              pageStoreOptions))
          .collect(ImmutableList.toImmutableList());
    }
  
    /**
     * Create an instance of PageStoreDir.
     *
     * @param cacheEvictorOptions
     * @param pageStoreOptions
     * @return PageStoreDir
     */
    static PageStoreDir createPageStoreDir(CacheEvictorOptions cacheEvictorOptions,
                                           PageStoreOptions pageStoreOptions) {
      switch (pageStoreOptions.getType()) {
        case LOCAL:
          return new LocalPageStoreDir(
              pageStoreOptions,
              PageStore.create(pageStoreOptions),
              CacheEvictor.create(cacheEvictorOptions)
          );
        case MEM:
          return new MemoryPageStoreDir(
              pageStoreOptions,
              (MemoryPageStore) PageStore.create(pageStoreOptions),
              CacheEvictor.create(cacheEvictorOptions)
          );
        default:
          throw new IllegalArgumentException(String.format("Unrecognized store type %s",
              pageStoreOptions.getType().name()));
      }
    }
  
    /**
     * @param fileBuckets number of buckets
     * @param fileId file id
     * @return file bucket
     */
    static String getFileBucket(int fileBuckets, String fileId) {
      return Integer.toString(Math.floorMod(fileId.hashCode(), fileBuckets));
    }
  
    /**
     * Clear the dir.
     * @param rootPath
     * @throws IOException when failed to clean up the specific location
     */
    static void clear(Path rootPath) throws IOException {
      Files.createDirectories(rootPath);
      LOG.info("Cleaning cache directory {}", rootPath);
      try (Stream<Path> stream = Files.list(rootPath)) {
        stream.forEach(path -> {
          try {
            FileUtils.deletePathRecursively(path.toString());
          } catch (IOException e) {
            PageStore.Metrics.CACHE_CLEAN_ERRORS.inc();
            LOG.warn("failed to delete {} in cache directory: {}", path,
                e.toString());
          }
        });
      }
    }
  
    /**
     * @return root path
     */
    Path getRootPath();
  
    /**
     * @return pageStore
     */
    PageStore getPageStore();
  
    /**
     * @return capacity
     */
    long getCapacityBytes();
  
    /**
     * Reset page store.
     */
    void reset() throws IOException;
  
    /**
     * Scan the pages under this dir.
     * @param pageInfoConsumer
     * @throws IOException
     */
    void scanPages(Consumer<Optional<PageInfo>> pageInfoConsumer) throws IOException;
  
    /**
     * @return cached bytes in this directory
     */
    long getCachedBytes();
  
    /**
     * @param pageInfo
     */
    void putPage(PageInfo pageInfo);
  
    /**
     * @param pageInfo
     */
    void putTempPage(PageInfo pageInfo);
  
    /**
     * @param fileId file id
     * @return if the temp file is added successfully
     */
    boolean putTempFile(String fileId);
  
    /**
     * @param bytes
     * @return if the bytes requested could be reserved
     */
    boolean reserve(long bytes);
  
    /**
     * @param bytes
     */
    void deleteTempPage(PageInfo bytes);
  
    /**
     * @param bytes
     * @return the bytes used after release
     */
    long deletePage(PageInfo bytes);
  
    /**
     * Release the pre-reserved space.
     * @param bytes
     * @return the bytes used after the release
     */
    long release(long bytes);
  
    /**
     * @param fileId
     * @return true if the file is contained, false otherwise
     */
    boolean hasFile(String fileId);
  
    /**
     * @param fileId
     * @return true if the temp file is contained, false otherwise
     */
    boolean hasTempFile(String fileId);
  
    /**
     * @return the evictor of this dir
     */
    CacheEvictor getEvictor();
  
    /**
     * Close the page store dir.
     */
    void close();
  
    /**
     * Commit a temporary file.
     * @param fileId
     */
    default void commit(String fileId) throws IOException {
      commit(fileId, fileId);
    }
  
    /**
     * Commit a temporary file with a new file ID.
     * @param fileId
     * @param newFileId
     */
    void commit(String fileId, String newFileId) throws IOException;
  
    /**
     * Abort a temporary file.
     * @param fileId
     */
    void abort(String fileId) throws IOException;
  }
  