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venv/lib/python3.10/site-packages/pyarrow/include/arrow/python/async.h

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+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+#pragma once
+
+#include <utility>
+
+#include "arrow/python/common.h"
+#include "arrow/status.h"
+#include "arrow/util/future.h"
+
+namespace arrow::py {
+
+/// \brief Bind a Python callback to an arrow::Future.
+///
+/// If the Future finishes successfully, py_wrapper is called with its
+/// result value and should return a PyObject*. If py_wrapper is successful,
+/// py_cb is called with its return value.
+///
+/// If either the Future or py_wrapper fails, py_cb is called with the
+/// associated Python exception.
+///
+/// \param future The future to bind to.
+/// \param py_cb The Python callback function. Will be passed the result of
+///   py_wrapper, or a Python exception if the future failed or one was
+///   raised by py_wrapper.
+/// \param py_wrapper A function (likely defined in Cython) to convert the C++
+///   result of the future to a Python object.
+template <typename T, typename PyWrapper = PyObject* (*)(T)>
+void BindFuture(Future<T> future, PyObject* py_cb, PyWrapper py_wrapper) {
+  Py_INCREF(py_cb);
+  OwnedRefNoGIL cb_ref(py_cb);
+
+  auto future_cb = [cb_ref = std::move(cb_ref),
+                    py_wrapper = std::move(py_wrapper)](Result<T> result) {
+    SafeCallIntoPythonVoid([&]() {
+      OwnedRef py_value_or_exc{WrapResult(std::move(result), std::move(py_wrapper))};
+      Py_XDECREF(
+          PyObject_CallFunctionObjArgs(cb_ref.obj(), py_value_or_exc.obj(), NULLPTR));
+      ARROW_WARN_NOT_OK(CheckPyError(), "Internal error in async call");
+    });
+  };
+  future.AddCallback(std::move(future_cb));
+}
+
+}  // namespace arrow::py