add nanoarrow header

Author: sfc-gh-aling

src/snowflake/connector/cpp/ArrowIterator/nanoarrow.hpp

@@ -0,0 +1,302 @@
+// 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.
+
+#include <vector>
+
+#include "nanoarrow.h"
+
+#ifndef NANOARROW_HPP_INCLUDED
+#define NANOARROW_HPP_INCLUDED
+
+/// \defgroup nanoarrow_hpp Nanoarrow C++ Helpers
+///
+/// The utilities provided in this file are intended to support C++ users
+/// of the nanoarrow C library such that C++-style resource allocation
+/// and error handling can be used with nanoarrow data structures.
+/// These utilities are not intended to mirror the nanoarrow C API.
+
+namespace nanoarrow {
+
+namespace internal {
+
+/// \defgroup nanoarrow_hpp-unique_base Base classes for Unique wrappers
+///
+/// @{
+
+static inline void init_pointer(struct ArrowSchema* data) { data->release = nullptr; }
+
+static inline void move_pointer(struct ArrowSchema* src, struct ArrowSchema* dst) {
+  ArrowSchemaMove(src, dst);
+}
+
+static inline void release_pointer(struct ArrowSchema* data) {
+  if (data->release != nullptr) {
+    data->release(data);
+  }
+}
+
+static inline void init_pointer(struct ArrowArray* data) { data->release = nullptr; }
+
+static inline void move_pointer(struct ArrowArray* src, struct ArrowArray* dst) {
+  ArrowArrayMove(src, dst);
+}
+
+static inline void release_pointer(struct ArrowArray* data) {
+  if (data->release != nullptr) {
+    data->release(data);
+  }
+}
+
+static inline void init_pointer(struct ArrowArrayStream* data) {
+  data->release = nullptr;
+}
+
+static inline void move_pointer(struct ArrowArrayStream* src,
+                                struct ArrowArrayStream* dst) {
+  ArrowArrayStreamMove(src, dst);
+}
+
+static inline void release_pointer(ArrowArrayStream* data) {
+  if (data->release != nullptr) {
+    data->release(data);
+  }
+}
+
+static inline void init_pointer(struct ArrowBuffer* data) { ArrowBufferInit(data); }
+
+static inline void move_pointer(struct ArrowBuffer* src, struct ArrowBuffer* dst) {
+  ArrowBufferMove(src, dst);
+}
+
+static inline void release_pointer(struct ArrowBuffer* data) { ArrowBufferReset(data); }
+
+static inline void init_pointer(struct ArrowBitmap* data) { ArrowBitmapInit(data); }
+
+static inline void move_pointer(struct ArrowBitmap* src, struct ArrowBitmap* dst) {
+  ArrowBitmapMove(src, dst);
+}
+
+static inline void release_pointer(struct ArrowBitmap* data) { ArrowBitmapReset(data); }
+
+static inline void init_pointer(struct ArrowArrayView* data) {
+  ArrowArrayViewInitFromType(data, NANOARROW_TYPE_UNINITIALIZED);
+}
+
+static inline void move_pointer(struct ArrowArrayView* src, struct ArrowArrayView* dst) {
+  ArrowArrayViewMove(src, dst);
+}
+
+static inline void release_pointer(struct ArrowArrayView* data) {
+  ArrowArrayViewReset(data);
+}
+
+/// \brief A unique_ptr-like base class for stack-allocatable objects
+/// \tparam T The object type
+template <typename T>
+class Unique {
+ public:
+  /// \brief Construct an invalid instance of T holding no resources
+  Unique() { init_pointer(&data_); }
+
+  /// \brief Move and take ownership of data
+  Unique(T* data) { move_pointer(data, &data_); }
+
+  /// \brief Move and take ownership of data wrapped by rhs
+  Unique(Unique&& rhs) : Unique(rhs.get()) {}
+
+  // These objects are not copyable
+  Unique(Unique& rhs) = delete;
+
+  /// \brief Get a pointer to the data owned by this object
+  T* get() noexcept { return &data_; }
+
+  /// \brief Use the pointer operator to access fields of this object
+  T* operator->() { return &data_; }
+
+  /// \brief Call data's release callback if valid
+  void reset() { release_pointer(&data_); }
+
+  /// \brief Call data's release callback if valid and move ownership of the data
+  /// pointed to by data
+  void reset(T* data) {
+    reset();
+    move_pointer(data, &data_);
+  }
+
+  /// \brief Move ownership of this object to the data pointed to by out
+  void move(T* out) { move_pointer(&data_, out); }
+
+  ~Unique() { reset(); }
+
+ protected:
+  T data_;
+};
+
+/// @}
+
+}  // namespace internal
+
+/// \defgroup nanoarrow_hpp-unique Unique object wrappers
+///
+/// The Arrow C Data interface, the Arrow C Stream interface, and the
+/// nanoarrow C library use stack-allocatable objects, some of which
+/// require initialization or cleanup.
+///
+/// @{
+
+/// \brief Class wrapping a unique struct ArrowSchema
+using UniqueSchema = internal::Unique<struct ArrowSchema>;
+
+/// \brief Class wrapping a unique struct ArrowArray
+using UniqueArray = internal::Unique<struct ArrowArray>;
+
+/// \brief Class wrapping a unique struct ArrowArrayStream
+using UniqueArrayStream = internal::Unique<struct ArrowArrayStream>;
+
+/// \brief Class wrapping a unique struct ArrowBuffer
+using UniqueBuffer = internal::Unique<struct ArrowBuffer>;
+
+/// \brief Class wrapping a unique struct ArrowBitmap
+using UniqueBitmap = internal::Unique<struct ArrowBitmap>;
+
+/// \brief Class wrapping a unique struct ArrowArrayView
+using UniqueArrayView = internal::Unique<struct ArrowArrayView>;
+
+/// @}
+
+/// \defgroup nanoarrow_hpp-array-stream ArrayStream helpers
+///
+/// These classes provide simple struct ArrowArrayStream implementations that
+/// can be extended to help simplify the process of creating a valid
+/// ArrowArrayStream implementation or used as-is for testing.
+///
+/// @{
+
+/// \brief An empty array stream
+///
+/// This class can be constructed from an enum ArrowType or
+/// struct ArrowSchema and implements a default get_next() method that
+/// always marks the output ArrowArray as released. This class can
+/// be extended with an implementation of get_next() for a custom
+/// source.
+class EmptyArrayStream {
+ public:
+  /// \brief Create an empty UniqueArrayStream from a struct ArrowSchema
+  ///
+  /// This object takes ownership of the schema and marks the source schema
+  /// as released.
+  static UniqueArrayStream MakeUnique(struct ArrowSchema* schema) {
+    UniqueArrayStream stream;
+    (new EmptyArrayStream(schema))->MakeStream(stream.get());
+    return stream;
+  }
+
+  virtual ~EmptyArrayStream() {}
+
+ protected:
+  UniqueSchema schema_;
+  struct ArrowError error_;
+
+  EmptyArrayStream(struct ArrowSchema* schema) : schema_(schema) {
+    error_.message[0] = '\0';
+  }
+
+  void MakeStream(struct ArrowArrayStream* stream) {
+    stream->get_schema = &get_schema_wrapper;
+    stream->get_next = &get_next_wrapper;
+    stream->get_last_error = &get_last_error_wrapper;
+    stream->release = &release_wrapper;
+    stream->private_data = this;
+  }
+
+  virtual int get_schema(struct ArrowSchema* schema) {
+    return ArrowSchemaDeepCopy(schema_.get(), schema);
+  }
+
+  virtual int get_next(struct ArrowArray* array) {
+    array->release = nullptr;
+    return NANOARROW_OK;
+  }
+
+  virtual const char* get_last_error() { return error_.message; }
+
+ private:
+  static int get_schema_wrapper(struct ArrowArrayStream* stream,
+                                struct ArrowSchema* schema) {
+    return reinterpret_cast<EmptyArrayStream*>(stream->private_data)->get_schema(schema);
+  }
+
+  static int get_next_wrapper(struct ArrowArrayStream* stream, struct ArrowArray* array) {
+    return reinterpret_cast<EmptyArrayStream*>(stream->private_data)->get_next(array);
+  }
+
+  static const char* get_last_error_wrapper(struct ArrowArrayStream* stream) {
+    return reinterpret_cast<EmptyArrayStream*>(stream->private_data)->get_last_error();
+  }
+
+  static void release_wrapper(struct ArrowArrayStream* stream) {
+    delete reinterpret_cast<EmptyArrayStream*>(stream->private_data);
+  }
+};
+
+/// \brief Implementation of an ArrowArrayStream backed by a vector of ArrowArray objects
+class VectorArrayStream : public EmptyArrayStream {
+ public:
+  /// \brief Create a UniqueArrowArrayStream from an existing array
+  ///
+  /// Takes ownership of the schema and the array.
+  static UniqueArrayStream MakeUnique(struct ArrowSchema* schema,
+                                      struct ArrowArray* array) {
+    std::vector<UniqueArray> arrays;
+    arrays.emplace_back(array);
+    return MakeUnique(schema, std::move(arrays));
+  }
+
+  /// \brief Create a UniqueArrowArrayStream from existing arrays
+  ///
+  /// This object takes ownership of the schema and arrays.
+  static UniqueArrayStream MakeUnique(struct ArrowSchema* schema,
+                                      std::vector<UniqueArray> arrays) {
+    UniqueArrayStream stream;
+    (new VectorArrayStream(schema, std::move(arrays)))->MakeStream(stream.get());
+    return stream;
+  }
+
+ protected:
+  VectorArrayStream(struct ArrowSchema* schema, std::vector<UniqueArray> arrays)
+      : EmptyArrayStream(schema), offset_(0), arrays_(std::move(arrays)) {}
+
+  int get_next(struct ArrowArray* array) {
+    if (offset_ < arrays_.size()) {
+      arrays_[offset_++].move(array);
+    } else {
+      array->release = nullptr;
+    }
+
+    return NANOARROW_OK;
+  }
+
+ private:
+  std::vector<UniqueArray> arrays_;
+  int64_t offset_;
+};
+
+/// @}
+
+}  // namespace nanoarrow
+
+#endif