// LOLLO NOTE important! The Mutex can work across AppDomains (ie across main app and background task) but only if you give it a name! // Also, if you declare initially owned true, the second thread trying to cross it will stay locked forever. So, declare it false. // All this is not well documented. public static async Task LoadAsync() { string errorMessage = string.Empty; try { await _suspensionSemaphore.WaitAsync().ConfigureAwait(false); if (_isLoaded) { return; } var file = await ApplicationData.Current.LocalCacheFolder.CreateFileAsync(SessionDataFilename, CreationCollisionOption.OpenIfExists).AsTask().ConfigureAwait(false); //string ssss = null; //this is useful when you debug and want to see the file as a string //using (IInputStream inStream = await file.OpenSequentialReadAsync()) //{ // using (StreamReader streamReader = new StreamReader(inStream.AsStreamForRead())) // { // ssss = streamReader.ReadToEnd(); // } //} using (IInputStream inStream = await file.OpenSequentialReadAsync().AsTask().ConfigureAwait(false)) { using (var iinStream = inStream.AsStreamForRead()) { DataContractSerializer serializer = new DataContractSerializer(typeof(PersistentData)); iinStream.Position = 0; PersistentData newPersistentData = (PersistentData)(serializer.ReadObject(iinStream)); await iinStream.FlushAsync().ConfigureAwait(false); PersistentData.GetInstanceWithProperties(newPersistentData); } } Debug.WriteLine("ended reading settings"); } catch (System.Xml.XmlException ex) { errorMessage = "could not restore the settings"; await Logger.AddAsync(ex.ToString(), Logger.FileErrorLogFilename); } catch (Exception ex) { errorMessage = "could not restore the settings"; await Logger.AddAsync(ex.ToString(), Logger.FileErrorLogFilename); } finally { PersistentData.GetInstance().LastMessage = errorMessage; IsLoaded = true; SemaphoreSlimSafeRelease.TryRelease(_suspensionSemaphore); } }
//protected Func<Task> _runAsSoonAsOpen = null; #endregion properties #region open close public async Task <bool> OpenAsync(object args = null) { if (_isOpen) { return(false); } lock (_isOpenSemaphoreLocker) { if (!SemaphoreSlimSafeRelease.IsAlive(_isOpenSemaphore)) { _isOpenSemaphore = new SemaphoreSlimSafeRelease(1, 1); } } try { await _isOpenSemaphore.WaitAsync().ConfigureAwait(false); if (!_isOpen) { lock (_ctsLocker) { _cts?.Dispose(); _cts = new SafeCancellationTokenSource(); _cancToken = _cts.Token; } await OpenMayOverrideAsync(args).ConfigureAwait(false); IsOpen = true; return(true); } } catch (Exception ex) { if (SemaphoreSlimSafeRelease.IsAlive(_isOpenSemaphore)) { await Logger.AddAsync(GetType().Name + ex.ToString(), Logger.ForegroundLogFilename); } } finally { SemaphoreSlimSafeRelease.TryRelease(_isOpenSemaphore); } return(false); }
public async Task <bool> OpenAsync(object args = null) { if (_isOpen) { return(await RunFunctionIfOpenAsyncA(delegate { IsEnabledAllowed = true; }).ConfigureAwait(false)); } lock (_isOpenSemaphoreLocker) { if (!SemaphoreSlimSafeRelease.IsAlive(_isOpenSemaphore)) { _isOpenSemaphore = new SemaphoreSlimSafeRelease(1, 1); } } try { await _isOpenSemaphore.WaitAsync().ConfigureAwait(false); if (!_isOpen) { lock (_ctsLocker) { _cts?.Dispose(); _cts = new SafeCancellationTokenSource(); _cancToken = _cts.Token; } await OpenMayOverrideAsync(args).ConfigureAwait(false); IsOpen = true; IsEnabledAllowed = true; await RegisterBackEventHandlersAsync().ConfigureAwait(false); //Logger.Add_TPL($"OpenableObservablePage.OpenAsync: {GetType().Name} is now open", Logger.AppEventsLogFilename, Logger.Severity.Info, false); return(true); } } catch (Exception ex) { if (SemaphoreSlimSafeRelease.IsAlive(_isOpenSemaphore)) { await Logger.AddAsync(GetType().Name + ex.ToString(), Logger.ForegroundLogFilename); } } finally { SemaphoreSlimSafeRelease.TryRelease(_isOpenSemaphore); } return(false); }