/// <summary>
/// Clean up the cache by deleting any cached items that have an expiration time
/// older than the specified time. This is a relatively expensive operation so should be
/// called sparingly.
/// </summary>
/// <param name="maximumExpirationTime">The maximum expiration time to delete. In other words, this call will delete
/// any cache items who's expiration is older than this value.</param>
/// <param name="complete">An Action that will be called when the cleanup operation has completed.</param>
public void Cleanup(DateTime maximumExpirationTime, Action complete)
{
PriorityQueue.AddStorageWorkItem(
() =>
{
int retries = 3;
while (retries-- > 0)
{
try {
// get the list of items.
//
var itemsToCleanup = from item in StoreProvider.GetItems()
where item.ExpirationTime <= maximumExpirationTime
select item;
// we snap the enumerable to an array to guard against any provider
// implementations that might have returned an enumerator that would be affected
// by the delete operation.
//
foreach (var item in itemsToCleanup.ToArray())
{
StoreProvider.Delete(item);
}
}
catch (Exception ex) {
Debug.WriteLine("Exception trying to clean up (attempt {0}): {1}", 3 - retries, ex);
// someetimes exceptions come out of the isostore stack trying to get the directory names,
// so we just wait a bit and try again.
//
Thread.Sleep(50);
}
}
// BUGBUG: What do to if this didn't ever actually complete succesfully.
if (complete != null)
{
PriorityQueue.AddUiWorkItem(() =>
{
complete();
}
);
}
}
);
}