org.cryptomator.cryptofs.DirectoryIdProvider.java Source code

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Here is the source code for org.cryptomator.cryptofs.DirectoryIdProvider.java

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/*******************************************************************************
 * Copyright (c) 2016 Sebastian Stenzel and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the accompanying LICENSE.txt.
 *
 * Contributors:
 *     Sebastian Stenzel - initial API and implementation
 *******************************************************************************/
package org.cryptomator.cryptofs;

import java.io.IOException;
import java.nio.file.Path;
import java.util.concurrent.ExecutionException;

import javax.inject.Inject;

import com.google.common.cache.CacheBuilder;
import com.google.common.cache.LoadingCache;

@PerFileSystem
class DirectoryIdProvider {

    private static final int MAX_CACHE_SIZE = 5000;

    private final LoadingCache<Path, String> ids;

    @Inject
    public DirectoryIdProvider(DirectoryIdLoader directoryIdLoader) {
        ids = CacheBuilder.newBuilder().maximumSize(MAX_CACHE_SIZE).build(directoryIdLoader);
    }

    public String load(Path dirFilePath) throws IOException {
        try {
            return ids.get(dirFilePath);
        } catch (ExecutionException e) {
            throw new IOException("Failed to load contents of directory file at path " + dirFilePath, e);
        }
    }

    /**
     * Removes the id currently associated with <code>dirFilePath</code> from cache. Useful during folder delete operations.
     * This method has no effect if the content of the given dirFile is not currently cached.
     * 
     * @param dirFilePath The dirFile for which the cache should be deleted.
     */
    public void delete(Path dirFilePath) {
        ids.invalidate(dirFilePath);
    }

    /**
     * Transfers ownership from the id currently associated with <code>srcDirFilePath</code> to <code>dstDirFilePath</code>. Usefule during folder move operations.
     * This method has no effect if the content of the source dirFile is not currently cached.
     * 
     * @param srcDirFilePath The dirFile that contained the cached id until now.
     * @param dstDirFilePath The dirFile that will contain the id from now on.
     */
    public void move(Path srcDirFilePath, Path dstDirFilePath) {
        String id = ids.getIfPresent(srcDirFilePath);
        if (id != null) {
            ids.put(dstDirFilePath, id);
            ids.invalidate(srcDirFilePath);
        }
    }

}