public int StoreSnapshot(
IReadOnlyCollection <Blob> blobs,
Fuzzy scanFuzzy,
DateTime creationTimeUtc,
Func <string, Stream> openRead)
{
var newSnapshot = new Snapshot(
_currentSnapshotId == null
? 0
: _currentSnapshotId.Value + 1,
creationTimeUtc,
WriteBlobs(blobs, scanFuzzy, openRead));
using var memoryStream = new MemoryStream(
DataConvert.ObjectToBytes(newSnapshot));
var newSnapshotReference = new SnapshotReference(
_salt,
_iterations,
WriteContent(AesGcmCrypto.GenerateNonce(), memoryStream));
_intRepository.StoreValue(
newSnapshot.SnapshotId,
DataConvert.ObjectToBytes(newSnapshotReference));
_currentSnapshotId = newSnapshot.SnapshotId;
_probe.StoredSnapshot(newSnapshot.SnapshotId);
return(newSnapshot.SnapshotId);
}
public void RetrieveContent(
IEnumerable <Uri> contentUris,
Stream outputStream)
{
contentUris.EnsureNotNull(nameof(contentUris));
outputStream.EnsureNotNull(nameof(outputStream));
foreach (var contentUri in contentUris)
{
try
{
var decrypted = AesGcmCrypto.Decrypt(
_uriRepository.RetrieveValue(contentUri),
_key.Value);
outputStream.Write(decrypted);
}
catch (CryptographicException e)
{
throw new ChunkyardException(
$"Could not decrypt content: {contentUri}",
e);
}
}
}
public SnapshotStore(
IRepository <Uri> uriRepository,
IRepository <int> intRepository,
FastCdc fastCdc,
string hashAlgorithmName,
IPrompt prompt,
IProbe probe,
int parallelizeChunkThreshold)
{
_uriRepository = uriRepository;
_intRepository = intRepository;
_fastCdc = fastCdc;
_hashAlgorithmName = hashAlgorithmName;
_probe = probe;
_parallelizeChunkThreshold = parallelizeChunkThreshold;
if (parallelizeChunkThreshold <= 0)
{
throw new ArgumentException(
"Value must be larger than zero",
nameof(parallelizeChunkThreshold));
}
_currentSnapshotId = FetchCurrentSnapshotId();
if (_currentSnapshotId == null)
{
_salt = AesGcmCrypto.GenerateSalt();
_iterations = AesGcmCrypto.Iterations;
}
else
{
var snapshotReference = GetSnapshotReference(
_currentSnapshotId.Value);
_salt = snapshotReference.Salt;
_iterations = snapshotReference.Iterations;
}
_key = new Lazy <byte[]>(() =>
{
var password = _currentSnapshotId == null
? prompt.NewPassword()
: prompt.ExistingPassword();
return(AesGcmCrypto.PasswordToKey(password, _salt, _iterations));
});
}
public static void Encrypt_And_Decrypt_Return_Input()
{
var expectedText = "Hello!";
var key = AesGcmCrypto.PasswordToKey(
"secret",
AesGcmCrypto.GenerateSalt(),
AesGcmCrypto.Iterations);
var cipherText = AesGcmCrypto.Encrypt(
AesGcmCrypto.GenerateNonce(),
Encoding.UTF8.GetBytes(expectedText),
key);
var actualText = Encoding.UTF8.GetString(
AesGcmCrypto.Decrypt(cipherText, key));
Assert.Equal(expectedText, actualText);
}
private BlobReference[] WriteBlobs(
IReadOnlyCollection <Blob> blobs,
Fuzzy scanFuzzy,
Func <string, Stream> openRead)
{
var currentBlobReferences = _currentSnapshotId == null
? new Dictionary <string, BlobReference>()
: GetSnapshot(_currentSnapshotId.Value).BlobReferences
.ToDictionary(br => br.Name, br => br);
return(blobs
.AsParallel()
.Select(blob =>
{
currentBlobReferences.TryGetValue(
blob.Name,
out var current);
if (!scanFuzzy.IsMatch(blob.Name) &&
current != null &&
current.ToBlob().Equals(blob))
{
return current;
}
// Known blobs should be encrypted using the same nonce
var nonce = current?.Nonce
?? AesGcmCrypto.GenerateNonce();
using var stream = openRead(blob.Name);
var blobReference = new BlobReference(
blob.Name,
blob.LastWriteTimeUtc,
nonce,
WriteContent(nonce, stream));
_probe.StoredBlob(blobReference);
return blobReference;
})
.OrderBy(blobReference => blobReference.Name)
.ToArray());
}
private IReadOnlyCollection <Uri> WriteContent(
byte[] nonce,
Stream stream)
{
Uri WriteChunk(byte[] chunk)
{
var encryptedData = AesGcmCrypto.Encrypt(
nonce,
chunk,
_key.Value);
var contentUri = Id.ComputeContentUri(
_hashAlgorithmName,
encryptedData);
_uriRepository.StoreValue(contentUri, encryptedData);
return(contentUri);
}
var expectedChunks = stream.Length / _fastCdc.AvgSize;
if (expectedChunks < _parallelizeChunkThreshold)
{
return(_fastCdc.SplitIntoChunks(stream)
.Select(WriteChunk)
.ToArray());
}
else
{
return(_fastCdc.SplitIntoChunks(stream)
.AsParallel()
.AsOrdered()
.Select(WriteChunk)
.ToArray());
}
}
