public async Task <IEnumerable <string> > FindFilesAsync(
string directoryPath,
string[] searchPatterns,
CancellationToken cancellationToken,
IProgress <int> numberOfFoundFilesProgress)
{
var fileCount = new Counter();
var task = Task.Run(() =>
{
if (!_DirectoryReader.Exists(directoryPath))
{
return((IEnumerable <string>) new string[0]);
}
return(searchPatterns
.AsParallel()
.WithCancellation(cancellationToken)
.WithMergeOptions(ParallelMergeOptions.AutoBuffered)
.SelectMany(p => _DirectoryReader
.GetDirectoryFilesRecursive(directoryPath, p)
.Aggregate(new List <string>(), (list, file) =>
{
cancellationToken.ThrowIfCancellationRequested();
var currentCounter = fileCount.Add(1);
if (currentCounter % 5 == 0)
{
numberOfFoundFilesProgress.Report(currentCounter);
}
list.Add(file);
return list;
})
)
.ToArray());
}, cancellationToken);
var items = await task;
numberOfFoundFilesProgress.Report(fileCount.Value);
return(items);
}