private void checkForBitFlip(DeterministicKey k) {
DeterministicKey parent = checkNotNull(k.getParent());
byte[] rederived =
HDKeyDerivation.deriveChildKeyBytesFromPublic(
parent, k.getChildNumber(), HDKeyDerivation.PublicDeriveMode.WITH_INVERSION)
.keyBytes;
byte[] actual = k.getPubKey();
if (!Arrays.equals(rederived, actual))
throw new IllegalStateException(
String.format(
"Bit-flip check failed: %s vs %s",
Arrays.toString(rederived), Arrays.toString(actual)));
}
/** Gets the median timestamp of the last 11 blocks */
private static long getMedianTimestampOfRecentBlocks(StoredBlock storedBlock, BlockStore store)
throws BlockStoreException {
long[] timestamps = new long[11];
int unused = 9;
timestamps[10] = storedBlock.getHeader().getTimeSeconds();
while (unused >= 0 && (storedBlock = storedBlock.getPrev(store)) != null)
timestamps[unused--] = storedBlock.getHeader().getTimeSeconds();
Arrays.sort(timestamps, unused + 1, 11);
return timestamps[unused + (11 - unused) / 2];
}
@Override
@Nullable
public StoredBlock get(Sha256Hash hash) throws BlockStoreException {
final MappedByteBuffer buffer = this.buffer;
if (buffer == null) throw new BlockStoreException("Store closed");
lock.lock();
try {
StoredBlock cacheHit = blockCache.get(hash);
if (cacheHit != null) return cacheHit;
if (notFoundCache.get(hash) != null) return null;
// Starting from the current tip of the ring work backwards until we have either found the
// block or
// wrapped around.
int cursor = getRingCursor(buffer);
final int startingPoint = cursor;
final int fileSize = getFileSize();
final byte[] targetHashBytes = hash.getBytes();
byte[] scratch = new byte[32];
do {
cursor -= RECORD_SIZE;
if (cursor < FILE_PROLOGUE_BYTES) {
// We hit the start, so wrap around.
cursor = fileSize - RECORD_SIZE;
}
// Cursor is now at the start of the next record to check, so read the hash and compare it.
buffer.position(cursor);
buffer.get(scratch);
if (Arrays.equals(scratch, targetHashBytes)) {
// Found the target.
StoredBlock storedBlock = StoredBlock.deserializeCompact(params, buffer);
blockCache.put(hash, storedBlock);
return storedBlock;
}
} while (cursor != startingPoint);
// Not found.
notFoundCache.put(hash, notFoundMarker);
return null;
} catch (ProtocolException e) {
throw new RuntimeException(e); // Cannot happen.
} finally {
lock.unlock();
}
}
