intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 28 insertions, 0 deletions

diff --git a/library/cpp/threading/equeue/equeue.h b/library/cpp/threading/equeue/equeue.h
new file mode 100644
index 0000000000..40dd342585
--- /dev/null
+++ b/library/cpp/threading/equeue/equeue.h
@@ -0,0 +1,28 @@
+#pragma once
+
+#include <util/thread/pool.h>
+#include <util/system/atomic.h>
+#include <util/generic/ptr.h>
+
+//actual queue limit will be (maxQueueSize - numBusyThreads) or 0
+class TElasticQueue: public IThreadPool {
+public:
+    explicit TElasticQueue(THolder<IThreadPool> slaveQueue);
+
+    bool Add(IObjectInQueue* obj) override;
+    size_t Size() const noexcept override;
+
+    void Start(size_t threadCount, size_t maxQueueSize) override;
+    void Stop() noexcept override;
+
+    size_t ObjectCount() const;
+private:
+    class TDecrementingWrapper;
+
+    bool TryIncCounter();
+private:
+    THolder<IThreadPool> SlaveQueue_;
+    size_t MaxQueueSize_ = 0;
+    TAtomic ObjectCount_ = 0;
+    TAtomic GuardCount_ = 0;
+};