Joseph Doherty
34 lines
1.1 KiB
C#
34 lines
1.1 KiB
C#
using ZB.MOM.WW.ScadaBridge.Commons.Entities.Kpi;
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namespace ZB.MOM.WW.ScadaBridge.KpiHistory;
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/// <summary>
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/// Root-provider-owned admission for source collections. Actor replacement must not
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/// start another call while an earlier cancellation-ignoring collection still owns its scope.
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/// Registration indices are stable because the root provider's service collection is immutable.
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/// </summary>
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internal sealed class KpiSourceAdmission
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{
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private readonly object _gate = new();
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private readonly Dictionary<int, Task<IReadOnlyList<KpiSample>>> _tasks = new();
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internal bool TryStart(
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int registrationIndex,
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Func<Task<IReadOnlyList<KpiSample>>> collect,
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out Task<IReadOnlyList<KpiSample>> collection)
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{
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lock (_gate)
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{
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if (_tasks.TryGetValue(registrationIndex, out var existing) && !existing.IsCompleted)
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{
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collection = existing;
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return false;
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}
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collection = Task.Run(collect);
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_tasks[registrationIndex] = collection;
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return true;
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}
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}
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}
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