org.codehaus.mojo.license.download.Cache Maven / Gradle / Ivy

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Maven plugin to download and collect license files from project dependencies.
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package org.codehaus.mojo.license.download;

/*
 * #%L
 * License Maven Plugin
 * %%
 * Copyright (C) 2018 Codehaus
 * %%
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation, either version 3 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 Lesser Public License for more details.
 *
 * You should have received a copy of the GNU General Lesser Public
 * License along with this program.  If not, see
 * .
 * #L%
 */

import java.io.File;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;

import org.codehaus.mojo.license.download.LicenseDownloader.LicenseDownloadResult;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * A simple {@link HashMap} based in-memory cache for storing {@link LicenseDownloadResult}s.
 *
 * @author Peter Palaga
 * @since 1.18
 */
public class Cache {
    private static final Logger LOG = LoggerFactory.getLogger(Cache.class);

    private final Map urlToFile = new HashMap<>();

    private final Map sha1ToFile = new HashMap<>();

    private final Map normalizedContentToFile = new HashMap<>();

    private final boolean enforcingUniqueSha1s;

    public Cache(boolean enforcingUniqueSha1s) {
        super();
        this.enforcingUniqueSha1s = enforcingUniqueSha1s;
    }

    /**
     * @param url the cache key to seek
     * @return the {@link LicenseDownloadResult} bound to the given {@code url} or {@code null} if no entry is bound to
     *         the given {@code url}
     */
    public LicenseDownloadResult get(String url) {
        return urlToFile.get(url);
    }

    /**
     * If this cache has a normalized version of a license file.
     *
     * @param normalizedContentChecksum Normalized file content checksum.
     * @return If the cache has a license file with the same normalized content.
     */
    public boolean hasNormalizedContentChecksum(String normalizedContentChecksum) {
        return normalizedContentToFile.get(normalizedContentChecksum) != null;
    }

    /**
     * Binds the given {@code url} to the give {@link LicenseDownloadResult}. If both {@link #enforcingUniqueSha1s} and
     * {@link LicenseDownloadResult#isSuccess()} are {@code true} and an entry with the given
     * {@link LicenseDownloadResult#getSha1()} already exists in {@link #sha1ToFile}, asserts that both the added and
     * the available entry point at the same file.
     *
     * @param url the URL the given {@code entry} comes from
     * @param entry the result of downloading from {@code url}
     */
    public void put(String url, LicenseDownloadResult entry) {
        if (entry.isSuccess()) {
            final String sha1 = entry.getSha1();
            final File entryFile = entry.getFile();
            final LicenseDownloadResult existing = sha1ToFile.get(sha1);
            if (existing == null) {
                sha1ToFile.put(sha1, entry);
            } else if (enforcingUniqueSha1s && !existing.getFile().equals(entryFile)) {
                final File existingFile = existing.getFile();
                final StringBuilder sb = new StringBuilder();
                for (Entry en : urlToFile.entrySet()) {
                    if (existingFile.equals(en.getValue().getFile())) {
                        if (sb.length() > 0) {
                            sb.append(", ");
                        }
                        sb.append(en.getKey());
                    }
                }
                throw new IllegalStateException("URL '" + url
                        + "' should belong to licenseUrlFileName having key '" + existingFile.getName()
                        + "' together with URLs '" + sb.toString() + "'");
            }
            final String normalizedContentChecksum = entry.getNormalizedContentChecksum();
            if (normalizedContentChecksum != null) {
                normalizedContentToFile.put(normalizedContentChecksum, entry);
            } else {
                LOG.warn("Couldn't find normalized content checksum for license download " + entry);
            }
        }
        urlToFile.put(url, entry);
    }
}