public IChangeSet<TObject, TKey> Change(IChangeSet<ExpirableItem<TObject, TKey>, TKey> updates)
{
_cache.Clone(updates);
var itemstoexpire = _cache.KeyValues
.OrderByDescending(exp => exp.Value.ExpireAt)
.Skip(_sizeLimit)
.Select(exp => new Change<TObject, TKey>(ChangeReason.Remove, exp.Key, exp.Value.Value))
.ToList();
if (itemstoexpire.Count > 0)
{
_cache.Remove(itemstoexpire.Select(exp => exp.Key));
}
var notifications = _cache.CaptureChanges();
var changed = notifications.Select(update => new Change<TObject, TKey>
(
update.Reason,
update.Key,
update.Current.Value,
update.Previous.HasValue ? update.Previous.Value.Value : Optional<TObject>.None
));
return new ChangeSet<TObject, TKey>(changed);
}
private IChangeSet <TDestination, TKey> ProcessUpdates(ChangeAwareCache <TDestination, TKey> cache, IEnumerable <TransformResult> transformedItems)
{
foreach (var result in transformedItems)
{
if (result.Success)
{
switch (result.Change.Reason)
{
case ChangeReason.Add:
case ChangeReason.Update:
cache.AddOrUpdate(result.Destination.Value, result.Key);
break;
case ChangeReason.Remove:
cache.Remove(result.Key);
break;
case ChangeReason.Refresh:
cache.Refresh(result.Key);
break;
}
}
else
{
_exceptionCallback(new Error <TSource, TKey>(result.Error, result.Change.Current, result.Change.Key));
}
}
return(cache.CaptureChanges());
}
private IChangeSet <TDestination, TKey> ProcessUpdates(ChangeAwareCache <TransformedItemContainer, TKey> cache, TransformResult[] transformedItems)
{
// check for errors and callback if a handler has been specified
var errors = transformedItems.Where(t => !t.Success).ToArray();
if (errors.Length > 0)
{
errors.ForEach(t => _exceptionCallback?.Invoke(new Error <TSource, TKey>(t.Error, t.Change.Current, t.Change.Key)));
}
foreach (var result in transformedItems.Where(t => t.Success))
{
TKey key = result.Key;
switch (result.Change.Reason)
{
case ChangeReason.Add:
case ChangeReason.Update:
cache.AddOrUpdate(result.Container.Value, key);
break;
case ChangeReason.Remove:
cache.Remove(key);
break;
case ChangeReason.Refresh:
cache.Refresh(key);
break;
}
}
var changes = cache.CaptureChanges();
var transformed = changes.Select(change => new Change <TDestination, TKey>(change.Reason, change.Key, change.Current.Destination, change.Previous.Convert(x => x.Destination), change.CurrentIndex, change.PreviousIndex));
return(new ChangeSet <TDestination, TKey>(transformed));
}
public static IChangeSet <TObject, TKey> RefreshFilteredFrom <TObject, TKey>(this ChangeAwareCache <TObject, TKey> filtered, Cache <TObject, TKey> allData, Func <TObject, bool> predicate)
where TKey : notnull
{
if (allData.Count == 0)
{
return(ChangeSet <TObject, TKey> .Empty);
}
foreach (var kvp in allData.KeyValues)
{
var existing = filtered.Lookup(kvp.Key);
var matches = predicate(kvp.Value);
if (matches)
{
if (!existing.HasValue)
{
filtered.Add(kvp.Value, kvp.Key);
}
}
else
{
if (existing.HasValue)
{
filtered.Remove(kvp.Key);
}
}
}
return(filtered.CaptureChanges());
}
/// <summary>
/// Initializes a new instance of the <see cref="LockFreeObservableCache{TObject, TKey}"/> class.
/// </summary>
/// <param name="source">The source.</param>
public LockFreeObservableCache(IObservable <IChangeSet <TObject, TKey> > source)
{
_updater = new CacheUpdater <TObject, TKey>(_innerCache);
var loader = source.Select(changes =>
{
_innerCache.Clone(changes);
return(_innerCache.CaptureChanges());
}).SubscribeSafe(_changes);
_cleanUp = Disposable.Create(() =>
{
loader.Dispose();
_changes.OnCompleted();
_countChanged.OnCompleted();
});
}
public IObservable <IChangeSet <TObject, TKey> > Run()
{
return(Observable.Create <IChangeSet <TObject, TKey> >(observer =>
{
long orderItemWasAdded = -1;
var locker = new object();
var cache = new ChangeAwareCache <ExpirableItem <TObject, TKey>, TKey>();
var sizeLimited = _source.Synchronize(locker)
.Scan(cache, (state, latest) =>
{
latest.Select(t =>
{
var key = _keySelector(t);
return CreateExpirableItem(t, key, ref orderItemWasAdded);
}).ForEach(ei => cache.AddOrUpdate(ei, ei.Key));
if (_limitSizeTo > 0 && state.Count > _limitSizeTo)
{
var toRemove = state.Count - _limitSizeTo;
//remove oldest items
cache.KeyValues
.OrderBy(exp => exp.Value.Index)
.Take(toRemove)
.ForEach(ei => cache.Remove(ei.Key));
}
return state;
})
.Select(state => state.CaptureChanges())
.Publish();
var timeLimited = (_expireAfter == null ? Observable.Never <IChangeSet <ExpirableItem <TObject, TKey>, TKey> >() : sizeLimited)
.Filter(ei => ei.ExpireAt != DateTime.MaxValue)
.GroupWithImmutableState(ei => ei.ExpireAt)
.MergeMany(grouping =>
{
var expireAt = grouping.Key.Subtract(_scheduler.Now.DateTime);
return Observable.Timer(expireAt, _scheduler).Select(_ => grouping);
})
.Synchronize(locker)
.Select(grouping =>
{
cache.Remove(grouping.Keys);
return cache.CaptureChanges();
});
var publisher = sizeLimited
.Merge(timeLimited)
.Cast(ei => ei.Value)
.NotEmpty()
.SubscribeSafe(observer);
return new CompositeDisposable(publisher, sizeLimited.Connect());
}));
}
public ChangeSet <TObject, TKey> Write(IChangeSet <TObject, TKey> changes, bool notifyChanges)
{
if (changes == null)
{
throw new ArgumentNullException(nameof(changes));
}
ChangeSet <TObject, TKey> result;
lock (_locker)
{
if (notifyChanges)
{
_changeAwareCache.Clone(changes);
result = _changeAwareCache.CaptureChanges();
}
else
{
_data.Clone(changes);
result = ChangeSet <TObject, TKey> .Empty;
}
}
return(result);
}
private IObservable <IChangeSet <TDestination, TDestinationKey> > CreateWithChangeSet()
{
if (_childChanges is null)
{
throw new InvalidOperationException("The childChanges is null and should not be.");
}
return(Observable.Create <IChangeSet <TDestination, TDestinationKey> >(
observer =>
{
var result = new ChangeAwareCache <TDestination, TDestinationKey>();
var transformed = _source.Transform(
(t, _) =>
{
// Only skip initial for first time Adds where there is initial data records
var locker = new object();
var collection = _manySelector(t);
var changes = _childChanges(t).Synchronize(locker).Skip(1);
return new ManyContainer(
() =>
{
lock (locker)
{
return collection.Select(m => new DestinationContainer(m, _keySelector(m))).ToArray();
}
},
changes);
}).Publish();
var outerLock = new object();
var initial = transformed.Synchronize(outerLock).Select(changes => new ChangeSet <TDestination, TDestinationKey>(new DestinationEnumerator(changes)));
var subsequent = transformed.MergeMany(x => x.Changes).Synchronize(outerLock);
var allChanges = initial.Merge(subsequent).Select(
changes =>
{
result.Clone(changes);
return result.CaptureChanges();
});
return new CompositeDisposable(allChanges.SubscribeSafe(observer), transformed.Connect());
}));
}
public IObservable <IChangeSet <TObject, TKey> > Run()
{
return(Observable.Create <IChangeSet <TObject, TKey> >(observer =>
{
var allData = new Cache <TObject, TKey>();
var filteredData = new ChangeAwareCache <TObject, TKey>();
Func <TObject, bool> predicate = t => false;
var locker = new object();
var refresher = LatestPredicateObservable()
.Synchronize(locker)
.Select(p =>
{
//set the local predicate
predicate = p;
//reapply filter using all data from the cache
return filteredData.RefreshFilteredFrom(allData, predicate);
});
var dataChanged = _source
// .Finally(observer.OnCompleted)
.Synchronize(locker)
.Select(changes =>
{
//maintain all data [required to re-apply filter]
allData.Clone(changes);
//maintain filtered data
filteredData.FilterChanges(changes, predicate);
//get latest changes
return filteredData.CaptureChanges();
});
return refresher
.Merge(dataChanged)
.NotEmpty()
.SubscribeSafe(observer);
}));
}
private IChangeSet <TDestination, TKey> ProcessUpdates(ChangeAwareCache <TransformedItemContainer, TKey> cache, IEnumerable <TransformResult> transformedItems)
{
foreach (var result in transformedItems)
{
if (result.Success)
{
switch (result.Change.Reason)
{
case ChangeReason.Add:
case ChangeReason.Update:
cache.AddOrUpdate(result.Container.Value, result.Key);
break;
case ChangeReason.Remove:
cache.Remove(result.Key);
break;
case ChangeReason.Refresh:
cache.Refresh(result.Key);
break;
}
}
else
{
_exceptionCallback(new Error <TSource, TKey>(result.Error, result.Change.Current, result.Change.Key));
}
}
var changes = cache.CaptureChanges();
var transformed = changes.Select(change => new Change <TDestination, TKey>(change.Reason,
change.Key,
change.Current.Destination,
change.Previous.Convert(x => x.Destination),
change.CurrentIndex,
change.PreviousIndex));
return(new ChangeSet <TDestination, TKey>(transformed));
}
private IObservable <IChangeSet <TDestination, TDestinationKey> > CreateWithChangeset()
{
return(Observable.Create <IChangeSet <TDestination, TDestinationKey> >(observer =>
{
var result = new ChangeAwareCache <TDestination, TDestinationKey>();
var transformed = _source.Transform((t, key) =>
{
var locker = new object();
var collection = _manyselector(t);
var changes = _childChanges(t).Synchronize(locker).Skip(1);
return new ManyContainer(() =>
{
lock (locker)
return collection.Select(m => new DestinationContainer(m, _keySelector(m)));
}, changes);
}).Publish();
var outerLock = new object();
var intial = transformed
.Synchronize(outerLock)
.Select(changes => new ChangeSet <TDestination, TDestinationKey>(new DestinationEnumerator(changes)));
var subsequent = transformed
.MergeMany(x => x.Changes)
.Synchronize(outerLock);
var allChanges = intial.Merge(subsequent).Select(changes =>
{
result.Clone(changes);
return result.CaptureChanges();
});
return new CompositeDisposable(allChanges.SubscribeSafe(observer), transformed.Connect());
}));
}
public IObservable <ChangeSet <TObject, TKey> > Run()
{
return(Observable.Create <ChangeSet <TObject, TKey> >
(
observer =>
{
var localCache = new ChangeAwareCache <TObject, TKey>();
var locker = new object();
var paused = _intialPauseState;
var timeoutDisposer = new SerialDisposable();
var intervalTimerDisposer = new SerialDisposable();
void ResumeAction()
{
//publish changes (if there are any)
var changes = localCache.CaptureChanges();
if (changes.Count > 0)
{
observer.OnNext(changes);
}
localCache = new ChangeAwareCache <TObject, TKey>();
}
IDisposable IntervalFunction()
{
return _intervalTimer
.Synchronize(locker)
.Finally(() => paused = false)
.Subscribe(_ =>
{
paused = false;
ResumeAction();
if (_intervalTimer != null)
{
paused = true;
}
});
}
if (_intervalTimer != null)
{
intervalTimerDisposer.Disposable = IntervalFunction();
}
var pausedHander = _pauseIfTrueSelector
.Synchronize(locker)
.Subscribe(p =>
{
paused = p;
if (!p)
{
//pause window has closed, so reset timer
if (_timeOut.HasValue)
{
timeoutDisposer.Disposable = Disposable.Empty;
}
ResumeAction();
}
else
{
if (_timeOut.HasValue)
{
timeoutDisposer.Disposable = Observable.Timer(_timeOut.Value, _scheduler)
.Synchronize(locker)
.Subscribe(_ =>
{
paused = false;
ResumeAction();
});
}
}
});
var publisher = _source
.Synchronize(locker)
.Subscribe(changes =>
{
localCache.Clone(changes);
//publish if not paused
if (!paused)
{
ResumeAction();
}
});
return new CompositeDisposable(publisher, pausedHander, timeoutDisposer, intervalTimerDisposer);
}
));
}
private IChangeSet <TObject, TKey> UpdateCombined(IChangeSet <TObject, TKey> updates)
{
//child caches have been updated before we reached this point.
foreach (var update in updates)
{
TKey key = update.Key;
switch (update.Reason)
{
case ChangeReason.Add:
case ChangeReason.Update:
{
// get the current key.
//check whether the item should belong to the cache
var cached = _combinedCache.Lookup(key);
var contained = cached.HasValue;
var match = MatchesConstraint(key);
if (match)
{
if (contained)
{
if (!ReferenceEquals(update.Current, cached.Value))
{
_combinedCache.AddOrUpdate(update.Current, key);
}
}
else
{
_combinedCache.AddOrUpdate(update.Current, key);
}
}
else
{
if (contained)
{
_combinedCache.Remove(key);
}
}
}
break;
case ChangeReason.Remove:
{
var cached = _combinedCache.Lookup(key);
var contained = cached.HasValue;
bool shouldBeIncluded = MatchesConstraint(key);
if (shouldBeIncluded)
{
var firstOne = _sourceCaches.Select(s => s.Lookup(key))
.SelectValues()
.First();
if (!cached.HasValue)
{
_combinedCache.AddOrUpdate(firstOne, key);
}
else if (!ReferenceEquals(firstOne, cached.Value))
{
_combinedCache.AddOrUpdate(firstOne, key);
}
}
else
{
if (contained)
{
_combinedCache.Remove(key);
}
}
}
break;
case ChangeReason.Refresh:
{
_combinedCache.Refresh(key);
}
break;
}
}
return(_combinedCache.CaptureChanges());
}
public IObservable <IChangeSet <TObject, TKey> > Run()
{
return(Observable.Create <IChangeSet <TObject, TKey> >(observer =>
{
var locker = new object();
//this is the resulting cache which produces all notifications
var resultCache = new ChangeAwareCache <TObject, TKey>();
//Transform to a merge container.
//This populates a RefTracker when the original source is subscribed to
var sourceLists = _source.Connect()
.Synchronize(locker)
.Transform(changeset => new MergeContainer(changeset))
.AsObservableList();
var sharedLists = sourceLists.Connect().Publish();
//merge the items back together
var allChanges = sharedLists
.MergeMany(mc => mc.Source)
.Synchronize(locker)
.Subscribe(changes =>
{
//Populate result list and check for changes
UpdateResultList(resultCache, sourceLists.Items.AsArray(), changes);
var notifications = resultCache.CaptureChanges();
if (notifications.Count != 0)
{
observer.OnNext(notifications);
}
});
//when an list is removed, need to
var removedItem = sharedLists
.OnItemRemoved(mc =>
{
//Remove items if required
ProcessChanges(resultCache, sourceLists.Items.AsArray(), mc.Cache.KeyValues);
if (_type == CombineOperator.And || _type == CombineOperator.Except)
{
var itemsToCheck = sourceLists.Items.SelectMany(mc2 => mc2.Cache.KeyValues);
ProcessChanges(resultCache, sourceLists.Items.AsArray(), itemsToCheck);
}
var notifications = resultCache.CaptureChanges();
if (notifications.Count != 0)
{
observer.OnNext(notifications);
}
})
.Subscribe();
//when an list is added or removed, need to
var sourceChanged = sharedLists
.WhereReasonsAre(ListChangeReason.Add, ListChangeReason.AddRange)
.ForEachItemChange(mc =>
{
ProcessChanges(resultCache, sourceLists.Items.AsArray(), mc.Current.Cache.KeyValues);
if (_type == CombineOperator.And || _type == CombineOperator.Except)
{
ProcessChanges(resultCache, sourceLists.Items.AsArray(), resultCache.KeyValues.ToArray());
}
var notifications = resultCache.CaptureChanges();
if (notifications.Count != 0)
{
observer.OnNext(notifications);
}
})
.Subscribe();
return new CompositeDisposable(sourceLists, allChanges, removedItem, sourceChanged, sharedLists.Connect());
}));
}
public IChangeSet <TObject, TKey> AsChangeSet()
{
return(_cache.CaptureChanges());
}
public IObservable <IChangeSet <TObject, TKey> > Run()
{
return(Observable.Create <IChangeSet <TObject, TKey> >(
observer =>
{
long orderItemWasAdded = -1;
var locker = new object();
if (_expireAfter is null && _limitSizeTo < 1)
{
return _source.Scan(
new ChangeAwareCache <TObject, TKey>(),
(state, latest) =>
{
if (latest is IList <TObject> list)
{
// zero allocation enumerator
var enumerableList = EnumerableIList.Create(list);
if (!_singleValueSource)
{
state.Remove(state.Keys.Except(enumerableList.Select(_keySelector)).ToList());
}
foreach (var item in enumerableList)
{
state.AddOrUpdate(item, _keySelector(item));
}
}
else
{
var enumerable = latest.ToList();
if (!_singleValueSource)
{
state.Remove(state.Keys.Except(enumerable.Select(_keySelector)).ToList());
}
foreach (var item in enumerable)
{
state.AddOrUpdate(item, _keySelector(item));
}
}
return state;
}).Select(state => state.CaptureChanges()).SubscribeSafe(observer);
}
var cache = new ChangeAwareCache <ExpirableItem <TObject, TKey>, TKey>();
var sizeLimited = _source.Synchronize(locker).Scan(
cache,
(state, latest) =>
{
latest.Select(
t =>
{
var key = _keySelector(t);
return CreateExpirableItem(t, key, ref orderItemWasAdded);
}).ForEach(ei => cache.AddOrUpdate(ei, ei.Key));
if (_limitSizeTo > 0 && state.Count > _limitSizeTo)
{
var toRemove = state.Count - _limitSizeTo;
// remove oldest items
cache.KeyValues.OrderBy(exp => exp.Value.Index).Take(toRemove).ForEach(ei => cache.Remove(ei.Key));
}
return state;
}).Select(state => state.CaptureChanges()).Publish();
var timeLimited = (_expireAfter is null ? Observable.Never <IChangeSet <ExpirableItem <TObject, TKey>, TKey> >() : sizeLimited).Filter(ei => ei.ExpireAt != DateTime.MaxValue).MergeMany(
grouping =>
{
var expireAt = grouping.ExpireAt.Subtract(_scheduler.Now.DateTime);
return Observable.Timer(expireAt, _scheduler).Select(_ => grouping);
}).Synchronize(locker).Select(
item =>
{
cache.Remove(item.Key);
return cache.CaptureChanges();
});
var publisher = sizeLimited.Merge(timeLimited).Cast(ei => ei.Value).NotEmpty().SubscribeSafe(observer);
return new CompositeDisposable(publisher, sizeLimited.Connect());
}));
}
/// <summary>
/// Sorts using the specified sorter. Will return null if there are no changes
/// </summary>
/// <param name="sortReason">The sort reason.</param>
/// <param name="changes">The changes.</param>
/// <returns></returns>
private ISortedChangeSet <TObject, TKey> DoSort(SortReason sortReason, IChangeSet <TObject, TKey> changes = null)
{
if (changes != null)
{
_cache.Clone(changes);
changes = _cache.CaptureChanges();
_haveReceivedData = true;
if (_comparer == null)
{
return(null);
}
}
//if the comparer is not set, return nothing
if (_comparer == null || !_haveReceivedData)
{
return(null);
}
if (!_initialised)
{
sortReason = SortReason.InitialLoad;
_initialised = true;
}
else if (changes != null && (_resetThreshold > 0 && changes.Count >= _resetThreshold))
{
sortReason = SortReason.Reset;
}
IChangeSet <TObject, TKey> changeSet;
switch (sortReason)
{
case SortReason.InitialLoad:
{
//For the first batch, changes may have arrived before the comparer was set.
//therefore infer the first batch of changes from the cache
_calculator = new IndexCalculator <TObject, TKey>(_comparer, _optimisations);
changeSet = _calculator.Load(_cache);
}
break;
case SortReason.Reset:
{
_calculator.Reset(_cache);
changeSet = changes;
}
break;
case SortReason.DataChanged:
{
changeSet = _calculator.Calculate(changes);
}
break;
case SortReason.ComparerChanged:
{
changeSet = _calculator.ChangeComparer(_comparer);
if (_resetThreshold > 0 && _cache.Count >= _resetThreshold)
{
sortReason = SortReason.Reset;
_calculator.Reset(_cache);
}
else
{
sortReason = SortReason.Reorder;
changeSet = _calculator.Reorder();
}
}
break;
case SortReason.Reorder:
{
changeSet = _calculator.Reorder();
}
break;
default:
throw new ArgumentOutOfRangeException(nameof(sortReason));
}
Debug.Assert(changeSet != null, "changeSet != null");
if ((sortReason == SortReason.InitialLoad || sortReason == SortReason.DataChanged) &&
changeSet.Count == 0)
{
return(null);
}
if (sortReason == SortReason.Reorder && changeSet.Count == 0)
{
return(null);
}
_sorted = new KeyValueCollection <TObject, TKey>((IReadOnlyCollection <KeyValuePair <TKey, TObject> >)_calculator.List, _comparer, sortReason, _optimisations);
return(new SortedChangeSet <TObject, TKey>(_sorted, changeSet));
}
