FilePermissions Class — spring-boot Architecture

Source Code

buildpack/spring-boot-buildpack-platform/src/main/java/org/springframework/boot/buildpack/platform/io/FilePermissions.java lines 34–87

public final class FilePermissions {

	private FilePermissions() {
	}

	/**
	 * Return the integer representation of the file permissions for a path, where the
	 * integer value conforms to the
	 * <a href="https://en.wikipedia.org/wiki/Umask">umask</a> octal notation.
	 * @param path the file path
	 * @return the integer representation
	 * @throws IOException if path permissions cannot be read
	 */
	public static int umaskForPath(Path path) throws IOException {
		Assert.notNull(path, "'path' must not be null");
		PosixFileAttributeView attributeView = Files.getFileAttributeView(path, PosixFileAttributeView.class);
		Assert.state(attributeView != null, "Unsupported file type for retrieving Posix attributes");
		return posixPermissionsToUmask(attributeView.readAttributes().permissions());
	}

	/**
	 * Return the integer representation of a set of Posix file permissions, where the
	 * integer value conforms to the
	 * <a href="https://en.wikipedia.org/wiki/Umask">umask</a> octal notation.
	 * @param permissions the set of {@code PosixFilePermission}s
	 * @return the integer representation
	 */
	public static int posixPermissionsToUmask(Collection<PosixFilePermission> permissions) {
		Assert.notNull(permissions, "'permissions' must not be null");
		int owner = permissionToUmask(permissions, PosixFilePermission.OWNER_EXECUTE, PosixFilePermission.OWNER_WRITE,
				PosixFilePermission.OWNER_READ);
		int group = permissionToUmask(permissions, PosixFilePermission.GROUP_EXECUTE, PosixFilePermission.GROUP_WRITE,
				PosixFilePermission.GROUP_READ);
		int other = permissionToUmask(permissions, PosixFilePermission.OTHERS_EXECUTE, PosixFilePermission.OTHERS_WRITE,
				PosixFilePermission.OTHERS_READ);
		return Integer.parseInt("" + owner + group + other, 8);
	}

	private static int permissionToUmask(Collection<PosixFilePermission> permissions, PosixFilePermission execute,
			PosixFilePermission write, PosixFilePermission read) {
		int value = 0;
		if (permissions.contains(execute)) {
			value += 1;
		}
		if (permissions.contains(write)) {
			value += 2;
		}
		if (permissions.contains(read)) {
			value += 4;
		}
		return value;
	}

}