ceph/src/arrow/cpp/src/arrow/io/transform.h

   1 // Licensed to the Apache Software Foundation (ASF) under one
   2 // or more contributor license agreements.  See the NOTICE file
   3 // distributed with this work for additional information
   4 // regarding copyright ownership.  The ASF licenses this file
   5 // to you under the Apache License, Version 2.0 (the
   6 // "License"); you may not use this file except in compliance
   7 // with the License.  You may obtain a copy of the License at
   8 //
   9 //   http://www.apache.org/licenses/LICENSE-2.0
  10 //
  11 // Unless required by applicable law or agreed to in writing,
  12 // software distributed under the License is distributed on an
  13 // "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  14 // KIND, either express or implied.  See the License for the
  15 // specific language governing permissions and limitations
  16 // under the License.
  17
  18 // Slow stream implementations, mainly for testing and benchmarking
  19
  20 #pragma once
  21
  22 #include <cstdint>
  23 #include <functional>
  24 #include <memory>
  25 #include <utility>
  26
  27 #include "arrow/io/interfaces.h"
  28 #include "arrow/util/visibility.h"
  29
  30 namespace arrow {
  31 namespace io {
  32
  33 class ARROW_EXPORT TransformInputStream : public InputStream {
  34  public:
  35   using TransformFunc =
  36       std::function<Result<std::shared_ptr<Buffer>>(const std::shared_ptr<Buffer>&)>;
  37
  38   TransformInputStream(std::shared_ptr<InputStream> wrapped, TransformFunc transform);
  39   ~TransformInputStream() override;
  40
  41   Status Close() override;
  42   Status Abort() override;
  43   bool closed() const override;
  44
  45   Result<int64_t> Read(int64_t nbytes, void* out) override;
  46   Result<std::shared_ptr<Buffer>> Read(int64_t nbytes) override;
  47
  48   Result<std::shared_ptr<const KeyValueMetadata>> ReadMetadata() override;
  49   Future<std::shared_ptr<const KeyValueMetadata>> ReadMetadataAsync(
  50       const IOContext& io_context) override;
  51
  52   Result<int64_t> Tell() const override;
  53
  54  protected:
  55   struct Impl;
  56   std::unique_ptr<Impl> impl_;
  57 };
  58
  59 }  // namespace io
  60 }  // namespace arrow