public IObservable <IChangeSet <TDestination, TKey> > Run()
{
return(Observable.Create <IChangeSet <TDestination, TKey> >(observer =>
{
var cache = new ChangeAwareCache <TransformedItemContainer, TKey>();
var transformer = _source.SelectTask(changes => DoTransform(cache, changes));
if (_forceTransform != null)
{
var locker = new object();
var forced = _forceTransform
.Synchronize(locker)
.SelectTask(shouldTransform => DoTransform(cache, shouldTransform));
transformer = transformer.Synchronize(locker).Merge(forced);
}
return transformer.SubscribeSafe(observer);
}));
}
private void ProcessChanges(ChangeAwareCache <TObject, TKey> target, MergeContainer[] sourceLists, IEnumerable <KeyValuePair <TKey, TObject> > items)
{
//check whether the item should be removed from the list (or in the case of And, added)
if (items is IList <KeyValuePair <TKey, TObject> > list)
{
//zero allocation enumerator
var enumerable = EnumerableIList.Create(list);
foreach (var item in enumerable)
{
ProcessItem(target, sourceLists, item.Value, item.Key);
}
}
else
{
foreach (var item in items)
{
ProcessItem(target, sourceLists, item.Value, item.Key);
}
}
}
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.Any())
{
errors.ForEach(t => _exceptionCallback(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.Evaluate:
cache.Evaluate(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));
}
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) =>
{
//Only skip initial for first time Adds where there is isinitial 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 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());
}));
}
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));
}
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 = _ => 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.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 void ProcessItem(ChangeAwareCache <TObject, TKey> target, MergeContainer[] sourceLists, TObject item, TKey key)
{
var cached = target.Lookup(key);
var shouldBeInResult = MatchesConstraint(sourceLists, key);
if (shouldBeInResult)
{
if (!cached.HasValue)
{
target.AddOrUpdate(item, key);
}
else if (!ReferenceEquals(item, cached.Value))
{
target.AddOrUpdate(item, key);
}
}
else
{
if (cached.HasValue)
{
target.Remove(key);
}
}
}
public CacheUpdater(ChangeAwareCache <TObject, TKey> cache, IKeySelector <TObject, TKey> keySelector = null)
{
_cache = cache ?? throw new ArgumentNullException(nameof(cache));
_keySelector = keySelector;
}
/// <summary>
/// Initialises the specified changes.
/// </summary>
/// <param name="cache">The cache.</param>
/// <returns></returns>
public void Reset(ChangeAwareCache <TObject, TKey> cache)
{
_list = cache.KeyValues.OrderBy(kv => kv, _comparer).ToList();
}
private async Task <IChangeSet <TDestination, TKey> > DoTransform(ChangeAwareCache <TransformedItemContainer, TKey> cache, IChangeSet <TSource, TKey> changes)
{
var transformed = await changes.SelectParallel(Transform, _maximumConcurrency);
return(ProcessUpdates(cache, transformed.ToArray()));
}
protected virtual TransformResult[] TransformChanges(ChangeAwareCache <TransformedItemContainer, TKey> cache, IEnumerable <Change <TSource, TKey> > changes)
{
return(changes.Select(Select).AsArray());
}
protected AbstractFilter(ChangeAwareCache <TObject, TKey> cache, Func <TObject, bool>?filter)
{
_cache = cache ?? throw new ArgumentNullException(nameof(cache));
Filter = filter ?? (_ => true);
}
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());
}));
}
public IObservable <IChangeSet <TDestination, TKey> > Run()
{
return(_source.Scan((ChangeAwareCache <TDestination, TKey>)null, (cache, changes) =>
{
if (cache == null)
{
cache = new ChangeAwareCache <TDestination, TKey>(changes.Count);
}
var concreteType = changes.ToConcreteType();
foreach (var change in concreteType)
{
switch (change.Reason)
{
case ChangeReason.Add:
case ChangeReason.Update:
{
TDestination transformed;
if (_exceptionCallback != null)
{
try
{
transformed = _transformFactory(change.Current, change.Previous, change.Key);
cache.AddOrUpdate(transformed, change.Key);
}
catch (Exception ex)
{
_exceptionCallback(new Error <TSource, TKey>(ex, change.Current, change.Key));
}
}
else
{
transformed = _transformFactory(change.Current, change.Previous, change.Key);
cache.AddOrUpdate(transformed, change.Key);
}
}
break;
case ChangeReason.Remove:
cache.Remove(change.Key);
break;
case ChangeReason.Refresh:
{
if (_transformOnRefresh)
{
var transformed = _transformFactory(change.Current, change.Previous, change.Key);
cache.AddOrUpdate(transformed, change.Key);
}
else
{
cache.Refresh(change.Key);
}
}
break;
case ChangeReason.Moved:
//Do nothing !
break;
}
}
return cache;
})
.Select(cache => cache.CaptureChanges())
.NotEmpty());
}
private IChangeSet <TDestination, TKey> DoTransform(ChangeAwareCache <TDestination, TKey> cache, IChangeSet <TSource, TKey> changes)
{
var transformed = changes.Select(ToDestination);
return(ProcessUpdates(cache, transformed));
}
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 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 <TDestination, TKey> DoTransform(ChangeAwareCache <TransformedItemContainer, TKey> cache, IChangeSet <TSource, TKey> changes)
{
var transformed = TransformChanges(changes);
return(ProcessUpdates(cache, transformed.ToArray()));
}
private void UpdateResultList(ChangeAwareCache <TObject, TKey> target, MergeContainer[] sourceLists, IChangeSet <TObject, TKey> changes)
{
changes.ForEach(change => { ProcessItem(target, sourceLists, change.Current, change.Key); });
}
private void ProcessChanges(ChangeAwareCache <TObject, TKey> target, MergeContainer[] sourceLists, IEnumerable <KeyValuePair <TKey, TObject> > items)
{
//check whether the item should be removed from the list (or in the case of And, added)
items.ForEach(item => { ProcessItem(target, sourceLists, item.Value, item.Key); });
}
public static void FilterChanges <TObject, TKey>(this ChangeAwareCache <TObject, TKey> cache, IChangeSet <TObject, TKey> changes, Func <TObject, bool> predicate)
where TKey : notnull
{
foreach (var change in changes.ToConcreteType())
{
var key = change.Key;
switch (change.Reason)
{
case ChangeReason.Add:
{
var current = change.Current;
if (predicate(current))
{
cache.AddOrUpdate(current, key);
}
}
break;
case ChangeReason.Update:
{
var current = change.Current;
if (predicate(current))
{
cache.AddOrUpdate(current, key);
}
else
{
cache.Remove(key);
}
}
break;
case ChangeReason.Remove:
cache.Remove(key);
break;
case ChangeReason.Refresh:
{
var existing = cache.Lookup(key);
if (predicate(change.Current))
{
if (!existing.HasValue)
{
cache.AddOrUpdate(change.Current, key);
}
else
{
cache.Refresh(key);
}
}
else
{
if (existing.HasValue)
{
cache.Remove(key);
}
}
}
break;
}
}
}
public static IChangeSet <TObject, TKey> GetInitialUpdates <TObject, TKey>(this ChangeAwareCache <TObject, TKey> source, Func <TObject, bool> filter = null)
{
var filtered = filter == null ? source.KeyValues : source.KeyValues.Where(kv => filter(kv.Value));
return(new ChangeSet <TObject, TKey>(filtered.Select(i => new Change <TObject, TKey>(ChangeReason.Add, i.Key, i.Value))));
}
public FilteredUpdater(ChangeAwareCache <TObject, TKey> cache, Func <TObject, bool> filter)
: base(cache, filter)
{
}
private async Task <IChangeSet <TDestination, TKey> > DoTransform(ChangeAwareCache <TransformedItemContainer, TKey> cache, IChangeSet <TSource, TKey> changes)
{
var transformed = await Task.WhenAll(changes.Select(Transform)).ConfigureAwait(false);
return(ProcessUpdates(cache, transformed));
}
public ReaderWriter(Func <TObject, TKey> keySelector = null)
{
_keySelector = keySelector;
_changeAwareCache = new ChangeAwareCache <TObject, TKey>(_data);
}
/// <summary>
/// Initialises the specified changes.
/// </summary>
/// <param name="cache">The cache.</param>
/// <returns></returns>
public void Reset(ChangeAwareCache <TObject, TKey> cache)
{
_list = new LinkedList <KeyValuePair <TKey, TObject> >(cache.KeyValues.OrderBy(kv => kv, _comparer));
}
