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.venv/Lib/site-packages/pyarrow/include/arrow/python/io.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 <memory>
+
+#include "arrow/io/interfaces.h"
+#include "arrow/io/transform.h"
+
+#include "arrow/python/common.h"
+#include "arrow/python/visibility.h"
+
+namespace arrow {
+namespace py {
+
+class ARROW_NO_EXPORT PythonFile;
+
+class ARROW_PYTHON_EXPORT PyReadableFile : public io::RandomAccessFile {
+ public:
+  explicit PyReadableFile(PyObject* file);
+  ~PyReadableFile() override;
+
+  Status Close() override;
+  Status Abort() override;
+  bool closed() const override;
+
+  Result<int64_t> Read(int64_t nbytes, void* out) override;
+  Result<std::shared_ptr<Buffer>> Read(int64_t nbytes) override;
+
+  // Thread-safe version
+  Result<int64_t> ReadAt(int64_t position, int64_t nbytes, void* out) override;
+
+  // Thread-safe version
+  Result<std::shared_ptr<Buffer>> ReadAt(int64_t position, int64_t nbytes) override;
+
+  Result<int64_t> GetSize() override;
+
+  Status Seek(int64_t position) override;
+
+  Result<int64_t> Tell() const override;
+
+ private:
+  std::unique_ptr<PythonFile> file_;
+};
+
+class ARROW_PYTHON_EXPORT PyOutputStream : public io::OutputStream {
+ public:
+  explicit PyOutputStream(PyObject* file);
+  ~PyOutputStream() override;
+
+  Status Close() override;
+  Status Abort() override;
+  bool closed() const override;
+  Result<int64_t> Tell() const override;
+  Status Write(const void* data, int64_t nbytes) override;
+  Status Write(const std::shared_ptr<Buffer>& buffer) override;
+
+ private:
+  std::unique_ptr<PythonFile> file_;
+  int64_t position_;
+};
+
+// TODO(wesm): seekable output files
+
+// A Buffer subclass that keeps a PyObject reference throughout its
+// lifetime, such that the Python object is kept alive as long as the
+// C++ buffer is still needed.
+// Keeping the reference in a Python wrapper would be incorrect as
+// the Python wrapper can get destroyed even though the wrapped C++
+// buffer is still alive (ARROW-2270).
+class ARROW_PYTHON_EXPORT PyForeignBuffer : public Buffer {
+ public:
+  static Status Make(const uint8_t* data, int64_t size, PyObject* base,
+                     std::shared_ptr<Buffer>* out);
+
+ private:
+  PyForeignBuffer(const uint8_t* data, int64_t size, PyObject* base)
+      : Buffer(data, size) {
+    Py_INCREF(base);
+    base_.reset(base);
+  }
+
+  OwnedRefNoGIL base_;
+};
+
+// All this rigamarole because Cython is really poor with std::function<>
+
+using TransformCallback = std::function<void(
+    PyObject*, const std::shared_ptr<Buffer>& src, std::shared_ptr<Buffer>* out)>;
+
+struct TransformInputStreamVTable {
+  TransformCallback transform;
+};
+
+ARROW_PYTHON_EXPORT
+std::shared_ptr<::arrow::io::InputStream> MakeTransformInputStream(
+    std::shared_ptr<::arrow::io::InputStream> wrapped, TransformInputStreamVTable vtable,
+    PyObject* arg);
+
+}  // namespace py
+}  // namespace arrow