/// <summary>
/// ライブラリに検索を要求、結果をキャッシュ
/// </summary>
/// <returns></returns>
private async Task <Record[]> RequestSearchAsync
(ISearchCriteria criteria, long offset, long takes)
{
if (criteria == null || takes <= 0)
{
throw new ArgumentException();
}
Record skipUntil = null;
/*
* if (offset > 0)
* {
* lock (this.Cache)
* {
* if (!this.Cache.TryGetValue(offset - 1, out skipUntil))
* {
* skipUntil = null;
* }
* }
* }*/
var result = await criteria.SearchAsync(library, offset, takes, skipUntil);
lock (this.Cache)
{
for (int i = 0; i < takes; i++)
{
if (i < result.Length)
{
this.Cache[offset + i] = result[i];
}
else
{
this.Cache[offset + i] = dummyRecord;
}
}
}
if (result.Length > 0)
{
NotifyCollectionChangedEventArgs eventArgs;
if (offset + result.Length > this.Length.Value)
{
eventArgs = new NotifyCollectionChangedEventArgs
(NotifyCollectionChangedAction.Add, result.ToList());
}
else
{
eventArgs = new NotifyCollectionChangedEventArgs
(NotifyCollectionChangedAction.Replace, result.ToList(), new List <Record>());
}
this.CollectionChanged?.Invoke(this, eventArgs);
if (this.CacheUpdatedSubject.HasObservers)
{
this.CacheUpdatedSubject.OnNext(new CacheUpdatedEventArgs()
{
Start = offset,
Length = result.Length,
});
}
}
return(result);
}
