private async Task <IList <T> > CheckAndLoadFromCacheAsync <T>(string fileName, Model.WorkTask workTask)
{
FileInfo fileInfo = new System.IO.FileInfo(fileName);
List <T> data = null;
string cachedFileName = this.GetDbTableNamePath(fileName);
if (this.dataFilesInfo.ContainsKey(fileName))
{
workTask.UpdateStatus($"загрузка данных из кэша ...");
workTask.IsIndeterminate = true;
DataFileRecord info = this.dataFilesInfo[fileName];
if (info.LastModified == fileInfo.LastWriteTime)
{
T[] result = await this.DeserializeDataAsync <T>(cachedFileName);
if (result != null)
{
data = new List <T>(result);
}
}
else
{
// расчет хэша файла и сравнение с ранее сохраненным
string hashAsString = this.CalculateSHA256(fileName);
if (string.Equals(info.Hash, hashAsString))
{
T[] result = await this.DeserializeDataAsync <T>(cachedFileName);
if (result != null)
{
data = new List <T>(result);
}
}
else
{
;
}
}
}
else
{
;
}
return(data);
}
private void StoreHashAndSaveData <T>(FileInfo fileInfo, WorkTask workTask, T[] data)
{
string fileName = fileInfo.FullName;
string msg = "вычисление контрольной-суммы файла ...";
workTask.UpdateStatus(msg);
workTask.IsIndeterminate = true;
string hashAsString = string.Empty;
bool isOk = false;
byte numberOfRetries = 1;
do
{
try
{
hashAsString = this.CalculateSHA256(fileName);
isOk = true;
}
catch (IOException ex)
{
this.callBackAction(ex);
workTask.UpdateStatus(string.Format("{0}\nфайл используется другим процессом, попытка #{1}", msg, numberOfRetries));
Task.Delay(1_000);
}
numberOfRetries++;
} while (isOk == false);
DataFileRecord dataFileRecord = new DataFileRecord(fileName, hashAsString, fileInfo.LastWriteTime);
if (this.dataFilesInfo.ContainsKey(fileName))
{
this.dataFilesInfo[fileName] = dataFileRecord;
}
else
{
this.dataFilesInfo.Add(fileName, dataFileRecord);
}
string cachedFileName = this.GetDbTableNamePath(fileName);
_ = this.SerializeDataAsync <T>(data, cachedFileName);
}
