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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.
// Slow stream implementations, mainly for testing and benchmarking
#pragma once
#include <cstdint>
#include <memory>
#include <utility>
#include "arrow/io/interfaces.h"
#include "arrow/util/visibility.h"
namespace arrow {
class Buffer;
class Status;
namespace io {
class ARROW_EXPORT LatencyGenerator {
public:
virtual ~LatencyGenerator();
void Sleep();
virtual double NextLatency() = 0;
static std::shared_ptr<LatencyGenerator> Make(double average_latency);
static std::shared_ptr<LatencyGenerator> Make(double average_latency, int32_t seed);
};
// XXX use ConcurrencyWrapper? It could increase chances of finding a race.
template <class StreamType>
class SlowInputStreamBase : public StreamType {
public:
SlowInputStreamBase(std::shared_ptr<StreamType> stream,
std::shared_ptr<LatencyGenerator> latencies)
: stream_(std::move(stream)), latencies_(std::move(latencies)) {}
SlowInputStreamBase(std::shared_ptr<StreamType> stream, double average_latency)
: stream_(std::move(stream)), latencies_(LatencyGenerator::Make(average_latency)) {}
SlowInputStreamBase(std::shared_ptr<StreamType> stream, double average_latency,
int32_t seed)
: stream_(std::move(stream)),
latencies_(LatencyGenerator::Make(average_latency, seed)) {}
protected:
std::shared_ptr<StreamType> stream_;
std::shared_ptr<LatencyGenerator> latencies_;
};
/// \brief An InputStream wrapper that makes reads slower.
///
/// Read() calls are made slower by an average latency (in seconds).
/// Actual latencies form a normal distribution closely centered
/// on the average latency.
/// Other calls are forwarded directly.
class ARROW_EXPORT SlowInputStream : public SlowInputStreamBase<InputStream> {
public:
~SlowInputStream() override;
using SlowInputStreamBase<InputStream>::SlowInputStreamBase;
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;
Result<std::string_view> Peek(int64_t nbytes) override;
Result<int64_t> Tell() const override;
};
/// \brief A RandomAccessFile wrapper that makes reads slower.
///
/// Similar to SlowInputStream, but allows random access and seeking.
class ARROW_EXPORT SlowRandomAccessFile : public SlowInputStreamBase<RandomAccessFile> {
public:
~SlowRandomAccessFile() override;
using SlowInputStreamBase<RandomAccessFile>::SlowInputStreamBase;
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;
Result<int64_t> ReadAt(int64_t position, int64_t nbytes, void* out) override;
Result<std::shared_ptr<Buffer>> ReadAt(int64_t position, int64_t nbytes) override;
Result<std::string_view> Peek(int64_t nbytes) override;
Result<int64_t> GetSize() override;
Status Seek(int64_t position) override;
Result<int64_t> Tell() const override;
};
} // namespace io
} // namespace arrow
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