public void VerifyCallbackWrappersCollectsUnusedWrappers()
{
DateTime endTime = DateTime.Now + TimeSpan.FromSeconds(19);
var callbackWrappers = new CallbackWrappers();
RunFullGarbageCollection();
long memoryAtStart = GC.GetTotalMemory(true);
while (DateTime.Now < endTime)
{
for (int i = 0; i < 128; ++i)
{
CreateCallbackWrapper(callbackWrappers);
}
RunFullGarbageCollection();
callbackWrappers.Collect();
RunFullGarbageCollection();
}
RunFullGarbageCollection();
long memoryAtEnd = GC.GetTotalMemory(true);
GC.KeepAlive(callbackWrappers);
long memory = memoryAtEnd - memoryAtStart;
Console.WriteLine("{0:N0} bytes used", memory);
Assert.IsTrue(memory < 1024 * 1024, "Test used too much memory. JetCallbackWrapper objects weren't collected.");
}
public void VerifyWrapperIsCollectedWhenCallbackIsCollected()
{
JET_CALLBACK callback = CreateCallback();
var callbackRef = new WeakReference(callback);
var callbackWrappers = new CallbackWrappers();
var wrapperRef = new WeakReference(callbackWrappers.Add(callback));
callback = null;
RunFullGarbageCollection();
callbackWrappers.Collect();
RunFullGarbageCollection();
// In DEBUG test code, the objects remain alive for an indeterminate amount of time, for some reason.
// Note that they do get collected if a RETAIL test code is used, even if the product code is DEBUG
// so it must be something to do with assigning the local variable 'callback' to null and the effect that
// it has on garbage collecting weak references to it.
#if !DEBUG
Assert.IsFalse(callbackRef.IsAlive);
Assert.IsFalse(wrapperRef.IsAlive);
#endif
// Avoid premature collection of these objects
GC.KeepAlive(callbackWrappers);
}
public void VerifyWrapperIsAliveWhenCallbackIsAlive()
{
JET_CALLBACK callback = CreateCallback();
var callbackWrappers = new CallbackWrappers();
var wrapperRef = new WeakReference(callbackWrappers.Add(callback));
RunFullGarbageCollection();
callbackWrappers.Collect();
RunFullGarbageCollection();
Assert.IsTrue(wrapperRef.IsAlive);
// Avoid premature collection of these objects
GC.KeepAlive(callback);
GC.KeepAlive(callbackWrappers);
}