internal void Unapply()
{
object sourceObject;
if (_weakSource != null && _weakSource.TryGetTarget(out sourceObject))
{
for (var i = 0; i < _parts.Count - 1; i++)
{
BindingExpressionPart part = _parts[i];
if (!part.IsSelf)
{
part.TryGetValue(sourceObject, out sourceObject);
}
part.Unsubscribe();
}
}
if (_trackingTemplatedParent)
{
BindableObject target = null;
if (_weakTarget?.TryGetTarget(out target) == true && target is Element elem)
{
elem.TemplatedParentChanged -= OnTargetTemplatedParentChanged;
}
}
_weakSource = null;
_weakTarget = null;
ClearAncestryChangeSubscriptions();
}
void OnElementBindingContextChanged(object sender, EventArgs e)
{
if (!(sender is Element elem) ||
!(this.Binding is Binding binding))
{
return;
}
BindableObject target = null;
if (_weakTarget?.TryGetTarget(out target) != true)
{
return;
}
object currentSource = null;
if (_weakSource?.TryGetTarget(out currentSource) == true)
{
// make sure that this isn't just a repeat notice
// from someone else in the chain about our already-resolved
// binding source
if (object.ReferenceEquals(currentSource, elem.BindingContext))
{
return;
}
}
binding.Unapply();
binding.Apply(null, target, _targetProperty);
}
private protected override void OnLoaded()
{
base.OnLoaded();
// TODO: Find a proper way to decide whether a CommandBar exists on canvas (within Page), or is mapped to the UINavigationController's NavigationBar.
CommandBar?commandBar = null;
_commandBar?.TryGetTarget(out commandBar);
if (_commandBar == null)
{
commandBar = TemplatedParent as CommandBar;
_commandBar = new WeakReference <CommandBar?>(commandBar);
_navigationBar = commandBar?.GetRenderer(RendererFactory).Native;
}
else
{
_navigationBar = commandBar?.ResetRenderer(RendererFactory).Native;
}
if (_navigationBar == null)
{
throw new InvalidOperationException("No NavigationBar from renderer");
}
_navigationBar.SetNeedsLayout();
var navigationBarSuperview = _navigationBar?.Superview;
// Allows the UINavigationController's NavigationBar instance to be moved to the Page. This feature
// is used in the context of the sample application to test NavigationBars outside of a NativeFramePresenter for
// UI Testing. In general cases, this should not happen as the bar may be moved back to to this presenter while
// another page is already visible, making this bar overlay on top of another.
if (FeatureConfiguration.CommandBar.AllowNativePresenterContent && (navigationBarSuperview == null || navigationBarSuperview is NativeCommandBarPresenter))
{
Content = _navigationBar;
}
var statusBar = StatusBar.GetForCurrentView();
statusBar.Showing += OnStatusBarChanged;
statusBar.Hiding += OnStatusBarChanged;
_statusBarSubscription.Disposable = Disposable.Create(() =>
{
statusBar.Showing -= OnStatusBarChanged;
statusBar.Hiding -= OnStatusBarChanged;
});
// iOS doesn't automatically update the navigation bar position when the status bar visibility changes.
void OnStatusBarChanged(StatusBar sender, object args)
{
_navigationBar !.SetNeedsLayout();
_navigationBar !.Superview.SetNeedsLayout();
}
}
private void SetupCollectionChanged(INotifyCollectionChanged?collection)
{
INotifyCollectionChanged?oldCollection = null;
_collectionReference?.TryGetTarget(out oldCollection);
if (oldCollection != null)
{
oldCollection.CollectionChanged -= OnItemsSourceCollectionChanged;
}
if (collection != null)
{
collection.CollectionChanged += OnItemsSourceCollectionChanged;
_collectionReference = new WeakReference <INotifyCollectionChanged>(collection);
}
}
public void WriteExpression(TextWriter writer)
{
if (writer == null)
{
throw new ArgumentNullException(nameof(writer));
}
TextWriter w = null;
TypeScriptWriter visitor = null;
_CachedTextWriter?.TryGetTarget(out w);
if (w == writer && _CachedTypeScriptWriter?.TryGetTarget(out visitor) == true)
{
Accept(visitor);
}
else
{
visitor = new TypeScriptWriter(writer);
_CachedTextWriter = new WeakReference <TextWriter>(writer);
_CachedTypeScriptWriter = new WeakReference <TypeScriptWriter>(visitor);
Accept(visitor);
}
}
private async void CalculateColor()
{
// HACK: yield control to avoid a race condition where things might not be initialized yet, resulting in no color being applied
await ThreadingTask.Delay(1);
View view = null;
T item;
if (RealmCollection != null &&
_view?.TryGetTarget(out view) == true &&
(item = view.BindingContext as T) != null)
{
try
{
Color backgroundColor;
if (item.IsCompleted)
{
backgroundColor = CompletedColor;
}
else
{
var index = RealmCollection.IndexOf(item);
var fraction = index / (double)Math.Max(13, RealmCollection.Count);
backgroundColor = GradientColorAtFraction(fraction);
}
view.BackgroundColor = backgroundColor;
}
catch
{
// Let's not crash because of a coloring fail :)
}
}
}
public static T Value <T>(this WeakReference <T> item) where T : class
{
T v = null;
item?.TryGetTarget(out v);
return(v);
}
private Regex GetServiceNameRegex(String category, string key)
{
ConcurrentDictionary <String, Regex> GetRegexCache()
{
ConcurrentDictionary <string, Regex> cache = null;
if (_regexCache?.TryGetTarget(out cache) ?? false)
{
return(cache);
}
cache = new ConcurrentDictionary <string, Regex>();
_regexCache = new WeakReference <ConcurrentDictionary <String, Regex> >(cache);
return(cache);
}
return(GetRegexCache().GetOrAdd($"{category}:{key}", k =>
{
StringBuilder servicePattern = new StringBuilder("^");
foreach (String c in key.Select(c => c.ToString()))
{
String charString = c.Equals("*") ? "\\S" : Regex.Escape(c);
servicePattern.Append(charString);
}
Regex rg = new Regex(servicePattern.ToString(), RegexOptions.Compiled, TimeSpan.FromSeconds(10));
return rg;
}));
}
/// <summary>
/// 【参考実装】Subscribe 時じゃなくて、IObservable に対して細工する版。
///
/// <paramref name="observable"/> をラップして、Subscribe が全部弱イベント購読になる <see cref="IObservable{T}"/> を作る。
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="observable"></param>
/// <returns></returns>
public static IObservable <T> AsWeakObservable <T>(this IObservable <T> observable)
{
return(Observable.Create((IObserver <T> observer) =>
{
WeakReference <IDisposable>?weakSubscription = null;
IDisposable?subscription = null;
subscription = observable.Subscribe(x =>
{
IDisposable d;
if (!(weakSubscription?.TryGetTarget(out d) ?? false))
{
subscription?.Dispose();
return;
}
observer.OnNext(x);
});
var s = new SingleAssignmentDisposable();
s.Disposable = subscription;
weakSubscription = new WeakReference <IDisposable>(s);
return s;
}));
}
/// <summary>
/// Gets the alive object in this <see cref="WeakReference{T}"/> or the <paramref name="defaultValue"/> if not alive.
/// </summary>
/// <typeparam name="T">The type of the object.</typeparam>
/// <param name="self">The weak reference.</param>
/// <param name="defaultValue">The default value.</param>
/// <returns></returns>
public static T GetOrDefault <T>(this WeakReference <T> self, T defaultValue = default(T)) where T : class
{
T value = defaultValue;
self?.TryGetTarget(out value);
return(value);
}
/// <summary>
/// @return The current {@link CustomTabsSession} object.
/// </summary>
/// <returns>The current session.</returns>
public static CustomTabsSession GetCurrentSession()
{
CustomTabsSession customTabsSession = null;
sCurrentSession?.TryGetTarget(out customTabsSession);
return(customTabsSession);
}
/// <summary>
/// 弱イベント購読。
/// 戻り値の <see cref="IDisposable"/> が誰からも参照されなくなったら自動的にイベント購読解除する。
/// </summary>
/// <typeparam name="T">イベント引数の型。</typeparam>
/// <param name="observable">イベント発生側。</param>
/// <param name="onNext">イベント受取側。</param>
/// <returns>イベント購読解除用の disposable。</returns>
/// <remarks>
/// 弱参照の性質上、<see cref="GC"/> がかかって初めて「誰も使ってない」判定を受ける。
/// それまではイベント購読解除されず、イベントが届き続ける。
/// GC タイミングに左右されるコードは推奨できないんで、可能な限り、
/// 戻り値の <see cref="IDisposable.Dispose"/> を明示的に呼ぶべき。
/// </remarks>
public static IDisposable WeakSubscribe <T>(this IObservable <T> observable, Action <T> onNext)
{
WeakReference <IDisposable>?weakSubscription = null;
IDisposable?subscription = null;
subscription = observable.Subscribe(x =>
{
IDisposable d;
if (!(weakSubscription?.TryGetTarget(out d) ?? false))
{
// 弱参照のターゲットが消えてたらイベント購読解除。
subscription?.Dispose();
return;
}
onNext(x);
});
// subscription は↑のラムダ式が参照を持っちゃうことになるので、
// 別の IDisposable を作ってラップ。
var s = new SingleAssignmentDisposable();
s.Disposable = subscription;
// 作った、外から呼ぶ用 IDisposable の弱参照を作る。
weakSubscription = new WeakReference <IDisposable>(s);
return(s);
}
protected override void OnCompletedCore()
{
Action oncomplete = null;
if (_onCompleted?.TryGetTarget(out oncomplete) == true)
{
oncomplete();
}
}
protected override void OnErrorCore(Exception error)
{
Action <Exception> onerror = null;
if (_onError?.TryGetTarget(out onerror) == true)
{
onerror(error);
}
}
protected override void OnNextCore(T value)
{
Action <T> onnext = null;
if (_onNext?.TryGetTarget(out onnext) == true)
{
onnext(value);
}
}
public void Execute(object parameter)
{
object executeTarget = null;
if (ExecuteTargetReference?.TryGetTarget(out executeTarget) ?? false)
{
ExecuteCallbackInfo.Invoke(executeTarget, new[] { parameter });
}
}
/// <summary>
/// Статичная цель всегда будет считаться полной.
/// </summary>
public bool IsEmpty()
{
if (_isStaticTarget)
{
return(false);
}
return(!(_target?.TryGetTarget(out _) ?? true));
}
internal static bool TryGet <T>(this WeakReference <T>?weakRef, [NotNullWhen(true)] out T?value) where T : class
{
if (weakRef?.TryGetTarget(out value) ?? false)
{
return(true);
}
value = null;
return(false);
}
internal NavigationView GetNavigationViewParent()
{
var result = default(NavigationView);
if (m_navigationView?.TryGetTarget(out result) ?? false)
{
return(result);
}
return(null);
}
internal SyntaxNode GetWeakRedElement(ref WeakReference <SyntaxNode> slot, int index)
{
SyntaxNode value = null;
if (slot?.TryGetTarget(out value) == true)
{
return(value);
}
return(CreateWeakItem(ref slot, index));
}
/// <summary>
/// Detaches from the subscribed event.
/// </summary>
public void Detach()
{
var source = _source;
if (source == null)
{
_weakSource?.TryGetTarget(out source);
}
if (source == null)
{
return;
}
_onDetachAction(this, source);
}
/// <summary>
/// Updates an existing gradient layer's parameters, if found, from the provided <see cref="T:XFGloss.Gradient"/>
/// instance.
/// </summary>
/// <param name="gradient">Gradient.</param>
void UpdateGradientLayerParams(Gradient gradient)
{
// If a layer currently exists but the gradient is being set to null...
if (gradient == null)
{
UIView view = null;
if ((bool)_gradientView?.TryGetTarget(out view) && view != null)
{
RemoveGradientLayer(view);
}
return;
}
UpdateRotation(gradient.Rotation);
UpdateSteps(gradient.Steps);
}
public void IGenericSharedAPI_ClearOrRemove_ReferenceRemovedFromCollection(bool useRemove)
{
if (typeof(T).IsValueType || IsReadOnly)
{
return;
}
IEnumerable <T> collection = GenericIEnumerableFactory();
WeakReference <object> wr = PopulateAndRemove(collection, useRemove);
Assert.True(SpinWait.SpinUntil(() =>
{
GC.Collect();
return(!wr.TryGetTarget(out _));
}, 30_000));
GC.KeepAlive(collection);
public override void HandleMessage(Message msg)
{
MusicService service;
weakReference.TryGetTarget(out service);
if (service != null && service.playback != null)
{
if (service.playback.IsPlaying)
{
LogHelper.Debug(Tag, "Ignoring delayed stop since the media player is in use.");
return;
}
LogHelper.Debug(Tag, "Stopping service with delay handler.");
service.StopSelf();
service.serviceStarted = false;
}
}
internal static CounterGroup GetCounterGroup(EventSource eventSource)
{
lock (s_counterGroupsLock)
{
int eventSourceIndex = EventListener.EventSourceIndex(eventSource);
EnsureEventSourceIndexAvailable(eventSourceIndex);
Debug.Assert(s_counterGroups != null);
WeakReference <CounterGroup> weakRef = CounterGroup.s_counterGroups[eventSourceIndex];
CounterGroup?ret = null;
if (weakRef == null || !weakRef.TryGetTarget(out ret))
{
ret = new CounterGroup(eventSource);
CounterGroup.s_counterGroups[eventSourceIndex] = new WeakReference <CounterGroup>(ret);
}
return(ret);
}
}
void OnCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
{
ListProxy proxy;
if (!_weakProxy.TryGetTarget(out proxy))
{
INotifyCollectionChanged collection;
if (_weakCollection.TryGetTarget(out collection))
{
collection.CollectionChanged -= OnCollectionChanged;
}
return;
}
proxy.OnCollectionChanged(sender, e);
}
// Returns -1 if the member is not in the chain or the
// chain is no longer valid.
int FindAncestryIndex(Element elem)
{
for (int i = 0; i < _ancestryChain.Count; i++)
{
WeakReference <Element> weak = _ancestryChain[i];
Element chainMember = null;
if (!weak.TryGetTarget(out chainMember))
{
return(-1);
}
else if (object.Equals(elem, chainMember))
{
return(i);
}
}
return(-1);
}
public static SharedResources GetSharedResources(ICanvasResourceCreator resourceCreator)
{
var device = resourceCreator.Device;
SharedResources sharedResources;
if (currentSharedResources.TryGetTarget(out sharedResources))
{
if (sharedResources.Device == device)
{
return(sharedResources);
}
}
sharedResources = new SharedResources(device);
currentSharedResources.SetTarget(sharedResources);
return(sharedResources);
}
public bool ContainsData(string dataName)
{
if (dataName == null)
{
return(false);
}
if (!dataDic.ContainsKey(dataName))
{
return(false);
}
WeakReference <object> wr = dataDic[dataName];
object o = null;
return(wr.TryGetTarget(out o));
}
public override void HandleMessage(Android.OS.Message msg)
{
switch (msg.What)
{
case MESSAGE_RETRY_CONNECTION:
FullWalletConfirmationButtonFragment fragment = null;
mWeakReference.TryGetTarget(out fragment);
if (fragment != null)
{
fragment.mGoogleApiClient.Connect();
}
break;
}
}
public static void GetValueTest()
{
ConditionalWeakTable<object, object> cwt = new ConditionalWeakTable<object, object>();
object key = new object();
object obj = null;
object value = cwt.GetValue(key, k => new object());
Assert.True(cwt.TryGetValue(key, out value));
Assert.Equal(value, cwt.GetOrCreateValue(key));
WeakReference<object> wrValue = new WeakReference<object>(value, false);
WeakReference<object> wrkey = new WeakReference<object>(key, false);
key = null;
value = null;
GC.Collect();
// key and value must be collected
Assert.False(wrValue.TryGetTarget(out obj));
Assert.False(wrkey.TryGetTarget(out obj));
}
[OuterLoop] // finalizer/GC interactions
public void TestNullTarget_CompletionNoCaching()
{
// Make sure that the Completion task returned by a NullTarget
// is not cached across all NullTargets. Since it'll never complete,
// that would be a potentially huge memory leak.
var state = new object();
var wro = new WeakReference<object>(state);
DataflowBlock.NullTarget<int>().Completion.ContinueWith(delegate { }, state);
state = null;
GC.Collect();
GC.WaitForPendingFinalizers();
GC.Collect();
Assert.False(wro.TryGetTarget(out state));
}
public void AllowFinalization()
{
// Explicitly do not dispose, to allow finalization to happen, just to try to verify
// that nothing fails when it does.
MemoryMappedFile mmf = MemoryMappedFile.CreateNew(null, 4096);
MemoryMappedViewStream s = mmf.CreateViewStream();
var mmfWeak = new WeakReference<MemoryMappedFile>(mmf);
var sWeak = new WeakReference<MemoryMappedViewStream>(s);
mmf = null;
s = null;
GC.Collect();
GC.WaitForPendingFinalizers();
GC.Collect();
Assert.False(mmfWeak.TryGetTarget(out mmf));
Assert.False(sWeak.TryGetTarget(out s));
}
