/// <summary> Write a stream to a store. </summary>
/// <remarks> Reads forward from the current position of the stream. </remarks>
public static Task <WrittenBlob> WriteAsync(
this IWriteOnlyStore store,
Stream stream,
CancellationToken cancel)
=>
// Default buffer size is 4MB, because Azure Storage likes it.
store.WriteAsync(stream, 4 * 1024 * 1024, cancel);
/// <summary> Write a buffer of bytes to the store. </summary>
public static async Task <WrittenBlob> WriteAsync(
this IWriteOnlyStore store,
byte[] buffer,
int offset,
int count,
CancellationToken cancel)
{
using (var writer = store.StartWriting())
return(await writer.WriteAndCommitAsync(buffer, offset, count, cancel).ConfigureAwait(false));
}
private static async Task <WrittenBlob> ImportBlobUnchecked(this IWriteOnlyStore store, IReadBlobRef srcBlob, CancellationToken cancel)
{
using (var writer = store.StartWriting())
{
using (var reader = await srcBlob.OpenAsync(cancel).ConfigureAwait(false))
{
await writer.WriteAsync(reader.ReadAsync, null, cancel).ConfigureAwait(false);
}
return(await writer.CommitAsync(cancel).ConfigureAwait(false));
}
}
/// <summary>
/// Copies blobs from <paramref name="source"/> store to <paramref name="destination"/> store.
/// Also, this checks that the blobs exist, and that there is no error in the hash of those blobs.
/// When these checks fail, an exception is raised, and the task fails.
/// </summary>
/// <param name="hashes">designates the blobs to be copied</param>
/// <param name="accountId">the account of <paramref name="source"/> store. only helps with error messages</param>
/// <returns></returns>
public static async Task <WrittenBlob[]> ImportBlobs(
this IWriteOnlyStore destination,
IReadOnlyStore source,
IReadOnlyCollection <Hash> hashes,
long?accountId = null,
CancellationToken cancel = default)
{
var checkExistTasks = hashes.Select(
h => source[h].ExistsAsync(cancel)
).ToArray();
bool[] exist = await Task.WhenAll(checkExistTasks);
int i = 0;
foreach (var h in hashes)
{
if (!exist[i])
{
throw new NoSuchBlobException(accountId?.ToString() ?? "<unknown>", h);
}
}
var copyTasks = hashes.Select(
h => destination.ImportBlobUnchecked(source[h], cancel)).ToArray();
var writtenBlobs = await Task.WhenAll(copyTasks).ConfigureAwait(false);
List <(Hash orig, Hash result)> badHashes = null;
i = 0;
foreach (var orig in hashes)
{
var blob = writtenBlobs[i++];
if (!blob.Hash.Equals(orig))
{
badHashes = badHashes ?? new List <(Hash orig, Hash result)>();
badHashes.Add((orig, blob.Hash));
}
}
if (badHashes != null)
{
string details = string.Join("\n", badHashes.Select(_ => $" {accountId}/{_.orig}: {_.result}"));
throw new Exception("Bad hash(es) detected: " + details);
}
return(writtenBlobs);
}
/// <summary> Write a stream to a store. </summary>
/// <remarks> Reads forward from the current position of the stream. </remarks>
public static async Task <WrittenBlob> WriteAsync(
this IWriteOnlyStore store,
Stream stream,
int bufferSize,
CancellationToken cancel)
{
// Don't allocate memory we don't need.
if (stream.CanSeek && stream.Length < bufferSize)
{
bufferSize = (int)stream.Length;
}
using (var writer = store.StartWriting())
{
var buffer = new byte[bufferSize];
await WriteAsync(writer, stream, buffer, null, true, cancel).ConfigureAwait(false);
return(await writer.CommitAsync(cancel).ConfigureAwait(false));
}
}
/// <summary> Write an entire buffer of bytes to the store. </summary>
public static Task <WrittenBlob> WriteAsync(
this IWriteOnlyStore store,
byte[] buffer,
CancellationToken cancel)
=>
store.WriteAsync(buffer, 0, buffer.Length, cancel);
