| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| package org.apache.commons.compress.compressors.xz; |
| |
| import java.util.HashMap; |
| import java.util.Map; |
| import org.apache.commons.compress.compressors.FileNameUtil; |
| |
| /** |
| * Utility code for the xz compression format. |
| * @ThreadSafe |
| * @since 1.4 |
| */ |
| public class XZUtils { |
| |
| private static final FileNameUtil fileNameUtil; |
| |
| /** |
| * XZ Header Magic Bytes begin a XZ file. |
| * |
| * <p>This is a copy of {@code org.tukaani.xz.XZ.HEADER_MAGIC} in |
| * XZ for Java version 1.5.</p> |
| */ |
| private static final byte[] HEADER_MAGIC = { |
| (byte) 0xFD, '7', 'z', 'X', 'Z', '\0' |
| }; |
| |
| enum CachedAvailability { |
| DONT_CACHE, CACHED_AVAILABLE, CACHED_UNAVAILABLE |
| } |
| |
| private static volatile CachedAvailability cachedXZAvailability; |
| |
| static { |
| final Map<String, String> uncompressSuffix = new HashMap<>(); |
| uncompressSuffix.put(".txz", ".tar"); |
| uncompressSuffix.put(".xz", ""); |
| uncompressSuffix.put("-xz", ""); |
| fileNameUtil = new FileNameUtil(uncompressSuffix, ".xz"); |
| cachedXZAvailability = CachedAvailability.DONT_CACHE; |
| try { |
| Class.forName("org.osgi.framework.BundleEvent"); |
| } catch (final Exception ex) { |
| setCacheXZAvailablity(true); |
| } |
| } |
| |
| /** Private constructor to prevent instantiation of this utility class. */ |
| private XZUtils() { |
| } |
| |
| /** |
| * Checks if the signature matches what is expected for a .xz file. |
| * |
| * <p>This is more or less a copy of the version found in {@link |
| * XZCompressorInputStream} but doesn't depend on the presence of |
| * XZ for Java.</p> |
| * |
| * @param signature the bytes to check |
| * @param length the number of bytes to check |
| * @return true if signature matches the .xz magic bytes, false otherwise |
| * @since 1.9 |
| */ |
| public static boolean matches(final byte[] signature, final int length) { |
| if (length < HEADER_MAGIC.length) { |
| return false; |
| } |
| |
| for (int i = 0; i < HEADER_MAGIC.length; ++i) { |
| if (signature[i] != HEADER_MAGIC[i]) { |
| return false; |
| } |
| } |
| |
| return true; |
| } |
| |
| /** |
| * Are the classes required to support XZ compression available? |
| * @since 1.5 |
| * @return true if the classes required to support XZ compression are available |
| */ |
| public static boolean isXZCompressionAvailable() { |
| final CachedAvailability cachedResult = cachedXZAvailability; |
| if (cachedResult != CachedAvailability.DONT_CACHE) { |
| return cachedResult == CachedAvailability.CACHED_AVAILABLE; |
| } |
| return internalIsXZCompressionAvailable(); |
| } |
| |
| private static boolean internalIsXZCompressionAvailable() { |
| try { |
| XZCompressorInputStream.matches(null, 0); |
| return true; |
| } catch (final NoClassDefFoundError error) { |
| return false; |
| } |
| } |
| |
| /** |
| * Detects common xz suffixes in the given filename. |
| * |
| * @param filename name of a file |
| * @return {@code true} if the filename has a common xz suffix, |
| * {@code false} otherwise |
| */ |
| public static boolean isCompressedFilename(final String filename) { |
| return fileNameUtil.isCompressedFilename(filename); |
| } |
| |
| /** |
| * Maps the given name of a xz-compressed file to the name that the |
| * file should have after uncompression. Commonly used file type specific |
| * suffixes like ".txz" are automatically detected and |
| * correctly mapped. For example the name "package.txz" is mapped to |
| * "package.tar". And any filenames with the generic ".xz" suffix |
| * (or any other generic xz suffix) is mapped to a name without that |
| * suffix. If no xz suffix is detected, then the filename is returned |
| * unmapped. |
| * |
| * @param filename name of a file |
| * @return name of the corresponding uncompressed file |
| */ |
| public static String getUncompressedFilename(final String filename) { |
| return fileNameUtil.getUncompressedFilename(filename); |
| } |
| |
| /** |
| * Maps the given filename to the name that the file should have after |
| * compression with xz. Common file types with custom suffixes for |
| * compressed versions are automatically detected and correctly mapped. |
| * For example the name "package.tar" is mapped to "package.txz". If no |
| * custom mapping is applicable, then the default ".xz" suffix is appended |
| * to the filename. |
| * |
| * @param filename name of a file |
| * @return name of the corresponding compressed file |
| */ |
| public static String getCompressedFilename(final String filename) { |
| return fileNameUtil.getCompressedFilename(filename); |
| } |
| |
| /** |
| * Whether to cache the result of the XZ for Java check. |
| * |
| * <p>This defaults to {@code false} in an OSGi environment and {@code true} otherwise.</p> |
| * @param doCache whether to cache the result |
| * @since 1.9 |
| */ |
| public static void setCacheXZAvailablity(final boolean doCache) { |
| if (!doCache) { |
| cachedXZAvailability = CachedAvailability.DONT_CACHE; |
| } else if (cachedXZAvailability == CachedAvailability.DONT_CACHE) { |
| final boolean hasXz = internalIsXZCompressionAvailable(); |
| cachedXZAvailability = hasXz ? CachedAvailability.CACHED_AVAILABLE // NOSONAR |
| : CachedAvailability.CACHED_UNAVAILABLE; |
| } |
| } |
| |
| // only exists to support unit tests |
| static CachedAvailability getCachedXZAvailability() { |
| return cachedXZAvailability; |
| } |
| } |