From a6423bf330c10089d7a0e2aaa8d971d0dcbb3fcf Mon Sep 17 00:00:00 2001
From: maybenotilya <maybenotilya@yandex-team.com>
Date: Fri, 17 Apr 2026 11:57:44 +0300
Subject: YT-26179: Add Abort for readers

* Changelog entry
  Type: feature
  Component: cpp-sdk

Add Abort for table readers
commit_hash:be5026883c90d18333f20468946f1e5a5b71839b
---
 yt/cpp/mapreduce/common/halting_stream.cpp | 67 ++++++++++++++++++++++++++++++
 1 file changed, 67 insertions(+)
 create mode 100644 yt/cpp/mapreduce/common/halting_stream.cpp

(limited to 'yt/cpp/mapreduce/common/halting_stream.cpp')

diff --git a/yt/cpp/mapreduce/common/halting_stream.cpp b/yt/cpp/mapreduce/common/halting_stream.cpp
new file mode 100644
index 00000000000..ba14d9af316
--- /dev/null
+++ b/yt/cpp/mapreduce/common/halting_stream.cpp
@@ -0,0 +1,67 @@
+#include "halting_stream.h"
+
+#include <yt/yt/core/actions/bind.h>
+#include <yt/yt/core/concurrency/async_stream.h>
+
+namespace NYT::NDetail {
+
+using namespace NConcurrency;
+
+////////////////////////////////////////////////////////////////////////////////
+
+class THaltingAsyncStream
+    : public IAsyncInputStream
+{
+public:
+    THaltingAsyncStream(
+        IAsyncInputStreamPtr underlying,
+        i64 bytesBeforeHalt)
+        : Underlying_(std::move(underlying))
+        , BytesBeforeHalt_(bytesBeforeHalt)
+    { }
+
+private:
+    void OnRead(TPromise<size_t> promise, const TErrorOr<size_t>& result)
+    {
+        if (result.IsOK()) {
+            BytesRead_ += result.Value();
+        }
+        promise.TrySet(result);
+    }
+
+    TFuture<size_t> Read(const TSharedMutableRef& buffer) override
+    {
+        if (BytesRead_ >= BytesBeforeHalt_) {
+            HaltPromise_ = NewPromise<size_t>();
+            return HaltPromise_.ToFuture();
+        }
+
+        auto limit = std::min(buffer.Size(), static_cast<size_t>(BytesBeforeHalt_ - BytesRead_));
+        auto promise = NewPromise<size_t>();
+        auto future = promise.ToFuture();
+
+        Underlying_->Read(buffer.Slice(0, limit)).Subscribe(
+            BIND(&THaltingAsyncStream::OnRead, MakeStrong(this), std::move(promise)));
+
+        return future;
+    }
+
+private:
+    IAsyncInputStreamPtr Underlying_;
+    const i64 BytesBeforeHalt_;
+    i64 BytesRead_ = 0;
+    TPromise<size_t> HaltPromise_;
+};
+
+////////////////////////////////////////////////////////////////////////////////
+
+IAsyncInputStreamPtr CreateHaltingAsyncStream(
+    IAsyncInputStreamPtr underlying,
+    i64 bytesBeforeHalt)
+{
+    return New<THaltingAsyncStream>(std::move(underlying), bytesBeforeHalt);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+} // namespace NYT::NDetail
-- 
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