/// <summary>
/// Open the named file asynchronously for reading.
/// </summary>
/// <exception cref="FileNotFoundException">Throws if the file is not found.</exception>
/// <remarks>
/// Unlike <see cref="IReadableFileSystem{T}.OpenReadOnlyAsync(T, FileShare)"/> this function throws an exception if the file is missing.
/// </remarks>
public static async Task <StreamWithLength> OpenReadOnlySafeAsync(this IAbsFileSystem fileSystem, AbsolutePath path, FileShare share)
{
var stream = await fileSystem.OpenReadOnlyAsync(path, share);
if (stream == null)
{
throw new FileNotFoundException($"The file '{path}' does not exist.");
}
return(stream.Value);
}
/// <inheritdoc />
public async Task <OpenStreamResult> OpenStreamAsync(Context context, ContentHash contentHash)
{
ObjectResult <SessionData> result = await _sessionState.GetDataAsync();
if (!result.Succeeded)
{
return(new OpenStreamResult(result));
}
int sessionId = result.Data.SessionId;
AbsolutePath tempPath = result.Data.TemporaryDirectory.CreateRandomFileName();
var placeFileResult = await PlaceFileAsync(
context,
contentHash,
tempPath,
FileAccessMode.ReadOnly,
FileReplacementMode.None,
FileRealizationMode.HardLink,
sessionId);
if (placeFileResult.Succeeded)
{
try
{
Stream stream = await _fileSystem.OpenReadOnlyAsync(tempPath, FileShare.Delete | FileShare.Read);
if (stream == null)
{
throw new ClientCanRetryException(context, $"Failed to open temp file {tempPath}. The service may have restarted");
}
return(new OpenStreamResult(stream));
}
catch (Exception ex) when(ex is DirectoryNotFoundException || ex is UnauthorizedAccessException)
{
throw new ClientCanRetryException(context, $"Failed to open temp file {tempPath}. The service may be restarting", ex);
}
catch (Exception ex) when(!(ex is ClientCanRetryException))
{
// The caller's retry policy needs to see ClientCanRetryExceptions in order to properly retry
return(new OpenStreamResult(ex));
}
}
else if (placeFileResult.Code == PlaceFileResult.ResultCode.NotPlacedContentNotFound)
{
return(new OpenStreamResult(OpenStreamResult.ResultCode.ContentNotFound, placeFileResult.ErrorMessage));
}
else
{
return(new OpenStreamResult(placeFileResult));
}
}