mirror of
https://github.com/aykhans/AzSuicideDataVisualization.git
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119 lines
3.9 KiB
C++
119 lines
3.9 KiB
C++
// Licensed to the Apache Software Foundation (ASF) under one
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// or more contributor license agreements. See the NOTICE file
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// distributed with this work for additional information
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// regarding copyright ownership. The ASF licenses this file
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// to you under the Apache License, Version 2.0 (the
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// "License"); you may not use this file except in compliance
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// with the License. You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing,
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// software distributed under the License is distributed on an
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// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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// KIND, either express or implied. See the License for the
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// specific language governing permissions and limitations
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// under the License.
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// Slow stream implementations, mainly for testing and benchmarking
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#pragma once
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#include <cstdint>
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#include <memory>
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#include <utility>
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#include "arrow/io/interfaces.h"
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#include "arrow/util/visibility.h"
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namespace arrow {
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class Buffer;
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class Status;
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namespace io {
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class ARROW_EXPORT LatencyGenerator {
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public:
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virtual ~LatencyGenerator();
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void Sleep();
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virtual double NextLatency() = 0;
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static std::shared_ptr<LatencyGenerator> Make(double average_latency);
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static std::shared_ptr<LatencyGenerator> Make(double average_latency, int32_t seed);
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};
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// XXX use ConcurrencyWrapper? It could increase chances of finding a race.
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template <class StreamType>
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class SlowInputStreamBase : public StreamType {
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public:
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SlowInputStreamBase(std::shared_ptr<StreamType> stream,
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std::shared_ptr<LatencyGenerator> latencies)
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: stream_(std::move(stream)), latencies_(std::move(latencies)) {}
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SlowInputStreamBase(std::shared_ptr<StreamType> stream, double average_latency)
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: stream_(std::move(stream)), latencies_(LatencyGenerator::Make(average_latency)) {}
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SlowInputStreamBase(std::shared_ptr<StreamType> stream, double average_latency,
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int32_t seed)
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: stream_(std::move(stream)),
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latencies_(LatencyGenerator::Make(average_latency, seed)) {}
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protected:
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std::shared_ptr<StreamType> stream_;
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std::shared_ptr<LatencyGenerator> latencies_;
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};
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/// \brief An InputStream wrapper that makes reads slower.
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///
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/// Read() calls are made slower by an average latency (in seconds).
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/// Actual latencies form a normal distribution closely centered
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/// on the average latency.
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/// Other calls are forwarded directly.
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class ARROW_EXPORT SlowInputStream : public SlowInputStreamBase<InputStream> {
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public:
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~SlowInputStream() override;
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using SlowInputStreamBase<InputStream>::SlowInputStreamBase;
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Status Close() override;
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Status Abort() override;
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bool closed() const override;
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Result<int64_t> Read(int64_t nbytes, void* out) override;
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Result<std::shared_ptr<Buffer>> Read(int64_t nbytes) override;
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Result<util::string_view> Peek(int64_t nbytes) override;
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Result<int64_t> Tell() const override;
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};
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/// \brief A RandomAccessFile wrapper that makes reads slower.
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///
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/// Similar to SlowInputStream, but allows random access and seeking.
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class ARROW_EXPORT SlowRandomAccessFile : public SlowInputStreamBase<RandomAccessFile> {
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public:
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~SlowRandomAccessFile() override;
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using SlowInputStreamBase<RandomAccessFile>::SlowInputStreamBase;
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Status Close() override;
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Status Abort() override;
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bool closed() const override;
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Result<int64_t> Read(int64_t nbytes, void* out) override;
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Result<std::shared_ptr<Buffer>> Read(int64_t nbytes) override;
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Result<int64_t> ReadAt(int64_t position, int64_t nbytes, void* out) override;
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Result<std::shared_ptr<Buffer>> ReadAt(int64_t position, int64_t nbytes) override;
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Result<util::string_view> Peek(int64_t nbytes) override;
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Result<int64_t> GetSize() override;
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Status Seek(int64_t position) override;
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Result<int64_t> Tell() const override;
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};
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} // namespace io
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} // namespace arrow
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