ZipFileTarArchive Class — spring-boot Architecture

Source Code

buildpack/spring-boot-buildpack-platform/src/main/java/org/springframework/boot/buildpack/platform/io/ZipFileTarArchive.java lines 41–108

public class ZipFileTarArchive implements TarArchive {

	static final long NORMALIZED_MOD_TIME = TarArchive.NORMALIZED_TIME.toEpochMilli();

	private final File zip;

	private final Owner owner;

	/**
	 * Creates an archive from the contents of the given {@code zip}. Each entry in the
	 * archive will be owned by the given {@code owner}.
	 * @param zip the zip to use as a source
	 * @param owner the owner of the tar entries
	 */
	public ZipFileTarArchive(File zip, Owner owner) {
		Assert.notNull(zip, "'zip' must not be null");
		Assert.notNull(owner, "'owner' must not be null");
		assertArchiveHasEntries(zip);
		this.zip = zip;
		this.owner = owner;
	}

	@Override
	public void writeTo(OutputStream outputStream) throws IOException {
		TarArchiveOutputStream tar = new TarArchiveOutputStream(outputStream);
		tar.setLongFileMode(TarArchiveOutputStream.LONGFILE_POSIX);
		try (ZipFile zipFile = ZipFile.builder().setFile(this.zip).get()) {
			Enumeration<ZipArchiveEntry> entries = zipFile.getEntries();
			while (entries.hasMoreElements()) {
				ZipArchiveEntry zipEntry = entries.nextElement();
				copy(zipEntry, zipFile.getInputStream(zipEntry), tar);
			}
		}
		tar.finish();
	}

	private void assertArchiveHasEntries(File file) {
		try (ZipFile zipFile = ZipFile.builder().setFile(file).get()) {
			Assert.state(zipFile.getEntries().hasMoreElements(), () -> "Archive file '" + file + "' is not valid");
		}
		catch (IOException ex) {
			throw new IllegalStateException("File '" + file + "' is not readable", ex);
		}
	}

	private void copy(ZipArchiveEntry zipEntry, InputStream zip, TarArchiveOutputStream tar) throws IOException {
		TarArchiveEntry tarEntry = convert(zipEntry);
		tar.putArchiveEntry(tarEntry);
		if (tarEntry.isFile()) {
			StreamUtils.copyRange(zip, tar, 0, tarEntry.getSize());
		}
		tar.closeArchiveEntry();
	}

	private TarArchiveEntry convert(ZipArchiveEntry zipEntry) {
		byte linkFlag = (zipEntry.isDirectory()) ? TarConstants.LF_DIR : TarConstants.LF_NORMAL;
		TarArchiveEntry tarEntry = new TarArchiveEntry(zipEntry.getName(), linkFlag, true);
		tarEntry.setUserId(this.owner.getUid());
		tarEntry.setGroupId(this.owner.getGid());
		tarEntry.setModTime(NORMALIZED_MOD_TIME);
		tarEntry.setMode(zipEntry.getUnixMode());
		if (!zipEntry.isDirectory()) {
			tarEntry.setSize(zipEntry.getSize());
		}
		return tarEntry;
	}

}