internal static async Task <bool> VerifyStreamAsync(Stream stream, IList <ChunkInfo> expectedChunks, ChunkDedupedFileContentHash expectedHash, CancellationToken cancellationToken)
{
ulong totalBytesChunked = 0;
var producedChunks = new List <ChunkInfo>(expectedChunks.Count);
var maxChunkSize = expectedChunks.Max((chunk) => chunk.Size);
var buffer = new byte[maxChunkSize];
foreach (var currentChunk in expectedChunks)
{
int bytesRead = await stream.ReadAsync(buffer, 0, (int)currentChunk.Size, cancellationToken);
if (bytesRead != currentChunk.Size)
{
return(false);
}
byte[] chunkHash = ChunkHasher.GetContentHash(
buffer,
0,
bytesRead).ToHashByteArray();
if (!chunkHash.SequenceEqual(currentChunk.Hash))
{
// Hash mismatch
return(false);
}
producedChunks.Add(new ChunkInfo(
totalBytesChunked,
currentChunk.Size,
chunkHash));
totalBytesChunked += (ulong)bytesRead;
}
if (stream.ReadByte() != -1)
{
// File content is longer
return(false);
}
var node = DedupNode.Create(producedChunks);
var hashBytesExcludingAlgorithm = node.Hash.Take(DedupSingleChunkHashInfo.Length).ToArray();
var actualHash = new ChunkDedupedFileContentHash(hashBytesExcludingAlgorithm);
return(expectedHash == actualHash);
}
/// <summary>
/// Verifies the content of a given chunk deduped file.
/// </summary>
/// <param name="filePath">
/// The path to the file.
/// </param>
/// <param name="expectedChunks">
/// The file's expected chunks.
/// </param>
/// <param name="expectedHash">
/// The expected hash of the file.
/// </param>
/// <param name="cancellationToken">
/// A cancellation token.
/// </param>
/// <returns>
/// true if the expected hash matches the file's content hash; false, otherwise.
/// </returns>
public static async Task <bool> VerifyFileAsync(string filePath, IList <ChunkInfo> expectedChunks, ChunkDedupedFileContentHash expectedHash, CancellationToken cancellationToken)
{
using (var fileStream = FileStreamUtility.OpenFileStreamForAsync(filePath, FileMode.Open, FileAccess.Read, FileShare.Read | FileShare.Delete))
{
return(await VerifyStreamAsync(fileStream, expectedChunks, expectedHash, cancellationToken));
}
}