public void ToggleRef_NonToggledObjectsShouldBeCollected()
{
// This test verifies that toggleable objects that aren't toggled aren't kept alive.
// We create a number of managed NSFileManager instance, get a native reference to each of them,
// and then we verify that the managed instance is collected.
var counter = 100;
var handles = new GCHandle [counter];
var pointers = new IntPtr [counter];
var t = new Thread(() =>
{
for (var i = 0; i < counter; i++)
{
var obj = new NSFileManager();
// do not toggle
obj.DangerousRetain(); // obtain a native reference
handles [i] = GCHandle.Alloc(obj, GCHandleType.Weak);
pointers [i] = obj.Handle;
}
})
{
IsBackground = true,
Name = "ToggleRef_NonToggledObjectsShouldBeCollected",
};
t.Start();
Assert.IsTrue(t.Join(TimeSpan.FromSeconds(10)), "Background thread completion");
var checkForCollectedManagedObjects = new Func <bool> (() =>
{
GC.Collect();
GC.WaitForPendingFinalizers();
for (var i = 0; i < counter; i++)
{
if (handles [i].Target == null)
{
return(true);
}
}
return(false);
});
// Iterate over the runloop in case something has to happen on the main thread for the objects to be collected.
TestRuntime.RunAsync(TimeSpan.FromSeconds(5), () => { }, checkForCollectedManagedObjects);
Assert.IsTrue(checkForCollectedManagedObjects(), "Any collected objects");
for (var i = 0; i < counter; i++)
{
var obj = Runtime.GetNSObject(pointers [i]);
Assert.IsNotNull(obj, $"Object #{i} couldn't be resurrected");
obj.DangerousRelease(); // release the native reference
obj.Dispose();
handles [i].Free();
}
}
public void ToggleRef_ToggledObjectsShouldNotBeCollected()
{
// This test verifies that toggleable objects that are toggled are kept alive while the native peer is alive.
// We create a number of managed NSFileManager instance, get a native reference to each of them,
// and then we verify that the managed instance won't be collected.
//
// NSFileManager instances are toggled when the [Weak]Delegate property is set.
var del = new NSFileManagerDelegate();
var counter = 100;
var handles = new GCHandle [counter];
var t = new Thread(() =>
{
for (var i = 0; i < counter; i++)
{
var obj = new NSFileManager();
obj.Delegate = del; // toggle
obj.DangerousRetain(); // obtain a native reference
handles [i] = GCHandle.Alloc(obj, GCHandleType.Weak);
}
})
{
IsBackground = true,
Name = "ToggleRef_ToggledObjectsShouldNotBeCollected",
};
t.Start();
Assert.IsTrue(t.Join(TimeSpan.FromSeconds(10)), "Background thread completion");
TestRuntime.RunAsync(TimeSpan.FromSeconds(2), () => { }, () =>
{
// Iterate over the runloop a bit to make sure we're just not collecting because objects are queued on for things to happen on the main thread
GC.Collect();
GC.WaitForPendingFinalizers();
return(false);
});
for (var i = 0; i < counter; i++)
{
var obj = (NSFileManager)handles [i].Target;
Assert.IsNotNull(obj, $"Object #{i} was unexpectedly collected.");
obj.DangerousRelease(); // release the native reference
obj.Dispose();
handles [i].Free();
}
}