public class FileDescLoader {
private static final Logger log = LoggerFactory.getLogger(FileDescLoader.class);
private static final ExecutorService exec = Executors.newCachedThreadPool();
public static void load(Collection<FileDesc> files, Path root, int blocSize, Pattern pattern)
throws IOException {
root = root.toAbsolutePath().normalize();
Visitor visitor = new Visitor(root, blocSize, pattern);
Files.walkFileTree(root, visitor);
for (Future<FileDesc> future : visitor.futures()) {
try {
files.add(future.get());
} catch (Exception e) {
log.error("", e);
}
}
}
/** @return matching bloc B bloc -> A bloc */
public static Map<Integer, Integer> diff(FileDesc a, FileDesc b) {
Map<Integer, List<IndexedHash>> blocA = new HashMap<Integer, List<IndexedHash>>();
int i = 0;
for (Bloc bloc : a.blocs) {
List<IndexedHash> l = blocA.get(bloc.roll);
if (l == null) {
l = new ArrayList<IndexedHash>();
blocA.put(bloc.roll, l);
}
l.add(new IndexedHash(i++, bloc.hash));
}
Map<Integer, Integer> map = new HashMap<Integer, Integer>();
loop:
for (i = 0; i < b.blocs.length; i++) {
Bloc blocB = b.blocs[i];
List<IndexedHash> list = blocA.get(blocB.roll);
if (list != null) {
for (IndexedHash bloc : list) {
if (blocB.hash.equals(bloc.h)) {
map.put(i, bloc.i);
continue loop;
}
}
}
}
return map;
}
public static FileDesc loadFile(Path root, Path file, int blocSize)
throws NoSuchAlgorithmException, FileNotFoundException, IOException {
MessageDigest md = MessageDigest.getInstance("SHA-512");
MessageDigest fileMd = MessageDigest.getInstance("SHA-512");
FileDesc desc = new FileDesc(file.toString(), null, null);
List<Bloc> list = new ArrayList<Bloc>();
try (FileInputStream fis = new FileInputStream(root.resolve(file).toString())) {
byte[] buf = new byte[blocSize];
byte[] h;
int s;
while ((s = fis.read(buf)) != -1) {
int c;
while (s < buf.length && (c = fis.read()) != -1) buf[s++] = (byte) c;
fileMd.update(buf, 0, s);
// padding
byte p = 0;
while (s < buf.length) buf[s++] = ++p;
h = md.digest(buf);
Bloc bloc = new Bloc(RollingChecksum.compute(buf), new Hash(h));
list.add(bloc);
}
h = fileMd.digest();
desc.fileHash = new Hash(h);
desc.blocs = list.toArray(new Bloc[0]);
}
return desc;
}
private static class Visitor implements FileVisitor<Path> {
private Path root;
private int blocSize;
private Matcher m;
private List<Future<FileDesc>> futures = new ArrayList<>();
public Visitor(Path root, int blocFile, Pattern pattern) {
this.root = root;
this.blocSize = blocFile;
this.m = pattern == null ? null : pattern.matcher("");
}
public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs)
throws IOException {
if (m != null) m.reset(root.relativize(dir).toString());
return m == null || m.matches() || m.hitEnd()
? FileVisitResult.CONTINUE
: FileVisitResult.SKIP_SUBTREE;
}
public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
if (attrs.isRegularFile()) {
if (m != null) m.reset(root.relativize(file).toString());
if (m == null || m.matches())
futures.add(exec.submit(new FileLoader(root, file, blocSize)));
}
return FileVisitResult.CONTINUE;
}
public FileVisitResult visitFileFailed(Path file, IOException exc) throws IOException {
return FileVisitResult.CONTINUE;
}
public FileVisitResult postVisitDirectory(Path dir, IOException exc) throws IOException {
return FileVisitResult.CONTINUE;
}
public List<Future<FileDesc>> futures() {
return futures;
}
}
private static class FileLoader implements Callable<FileDesc> {
private Path file;
private int blocSize;
private Path root;
public FileLoader(Path root, Path file, int blocSize) throws IOException {
this.root = root;
this.file = file;
this.blocSize = blocSize;
}
public FileDesc call() throws Exception {
return loadFile(root, root.relativize(file), blocSize);
}
}
public static class IndexedHash {
public int i;
public Hash h;
public IndexedHash(int i, Hash h) {
this.i = i;
this.h = h;
}
}
}
/**
* A SecureRandom implementation that is able to override the standard JVM provided implementation,
* and which simply serves random numbers by reading /dev/urandom. That is, it delegates to the
* kernel on UNIX systems and is unusable on other platforms. Attempts to manually set the seed are
* ignored. There is no difference between seed bytes and non-seed bytes, they are all from the same
* source.
*/
public class LinuxSecureRandom extends SecureRandomSpi {
private static final FileInputStream urandom;
private static class LinuxSecureRandomProvider extends Provider {
public LinuxSecureRandomProvider() {
super(
"LinuxSecureRandom",
1.0,
"A Linux specific random number provider that uses /dev/urandom");
put("SecureRandom.LinuxSecureRandom", LinuxSecureRandom.class.getName());
}
}
private static final Logger log = LoggerFactory.getLogger(LinuxSecureRandom.class);
static {
try {
File file = new File("/dev/urandom");
// This stream is deliberately leaked.
urandom = new FileInputStream(file);
if (urandom.read() == -1) throw new RuntimeException("/dev/urandom not readable?");
// Now override the default SecureRandom implementation with this one.
int position = Security.insertProviderAt(new LinuxSecureRandomProvider(), 1);
if (position != -1) log.info("Secure randomness will be read from {} only.", file);
else log.info("Randomness is already secure.");
} catch (FileNotFoundException e) {
// Should never happen.
log.error("/dev/urandom does not appear to exist or is not openable");
throw new RuntimeException(e);
} catch (IOException e) {
log.error("/dev/urandom does not appear to be readable");
throw new RuntimeException(e);
}
}
private final DataInputStream dis;
public LinuxSecureRandom() {
// DataInputStream is not thread safe, so each random object has its own.
dis = new DataInputStream(urandom);
}
@Override
protected void engineSetSeed(byte[] bytes) {
// Ignore.
}
@Override
protected void engineNextBytes(byte[] bytes) {
try {
dis.readFully(bytes); // This will block until all the bytes can be read.
} catch (IOException e) {
throw new RuntimeException(e); // Fatal error. Do not attempt to recover from this.
}
}
@Override
protected byte[] engineGenerateSeed(int i) {
byte[] bits = new byte[i];
engineNextBytes(bits);
return bits;
}
}