1 files changed, 80 insertions, 0 deletions
diff --git a/library/cpp/threading/equeue/equeue.cpp b/library/cpp/threading/equeue/equeue.cpp
new file mode 100644
index 00000000000..54a848e912a
--- /dev/null
+++ b/library/cpp/threading/equeue/equeue.cpp
@@ -0,0 +1,80 @@
+#include "equeue.h"
+
+TElasticQueue::TElasticQueue(THolder<IThreadPool> slaveQueue)
+    : SlaveQueue_(std::move(slaveQueue))
+{
+}
+
+size_t TElasticQueue::ObjectCount() const {
+    return (size_t)AtomicGet(ObjectCount_);
+}
+
+bool TElasticQueue::TryIncCounter() {
+    if ((size_t)AtomicIncrement(GuardCount_) > MaxQueueSize_) {
+        AtomicDecrement(GuardCount_);
+        return false;
+    }
+
+    return true;
+}
+
+
+
+class TElasticQueue::TDecrementingWrapper: TNonCopyable, public IObjectInQueue {
+public:
+    TDecrementingWrapper(IObjectInQueue* realObject, TElasticQueue* queue)
+        : RealObject_(realObject)
+        , Queue_(queue)
+    {
+        AtomicIncrement(Queue_->ObjectCount_);
+    }
+
+    ~TDecrementingWrapper() override {
+        AtomicDecrement(Queue_->ObjectCount_);
+        AtomicDecrement(Queue_->GuardCount_);
+    }
+private:
+    void Process(void *tsr) override {
+        THolder<TDecrementingWrapper> self(this);
+        RealObject_->Process(tsr);
+    }
+private:
+    IObjectInQueue* const RealObject_;
+    TElasticQueue* const Queue_;
+};
+
+
+
+bool TElasticQueue::Add(IObjectInQueue* obj) {
+    if (!TryIncCounter()) {
+        return false;
+    }
+
+    THolder<TDecrementingWrapper> wrapper;
+    try {
+        wrapper.Reset(new TDecrementingWrapper(obj, this));
+    } catch (...) {
+        AtomicDecrement(GuardCount_);
+        throw;
+    }
+
+    if (SlaveQueue_->Add(wrapper.Get())) {
+        Y_UNUSED(wrapper.Release());
+        return true;
+    } else {
+        return false;
+    }
+}
+
+void TElasticQueue::Start(size_t threadCount, size_t maxQueueSize) {
+    MaxQueueSize_ = maxQueueSize;
+    SlaveQueue_->Start(threadCount, maxQueueSize);
+}
+
+void TElasticQueue::Stop() noexcept {
+    return SlaveQueue_->Stop();
+}
+
+size_t TElasticQueue::Size() const noexcept {
+    return SlaveQueue_->Size();
+}