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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.
#include "contrib/libs/apache/arrow_next/cpp/src/arrow/io/slow.h"
#include <algorithm>
#include <cstring>
#include <mutex>
#include <random>
#include <thread>
#include <utility>
#include "contrib/libs/apache/arrow_next/cpp/src/arrow/buffer.h"
#include "contrib/libs/apache/arrow_next/cpp/src/arrow/io/util_internal.h"
#include "contrib/libs/apache/arrow_next/cpp/src/arrow/result.h"
#include "contrib/libs/apache/arrow_next/cpp/src/arrow/status.h"
#include "contrib/libs/apache/arrow_next/cpp/src/arrow/util/io_util.h"
#include "contrib/libs/apache/arrow_next/cpp/src/arrow/util/logging.h"
namespace arrow20 {
namespace io {
// Multiply the average by this ratio to get the intended standard deviation
static constexpr double kStandardDeviationRatio = 0.1;
class LatencyGeneratorImpl : public LatencyGenerator {
public:
~LatencyGeneratorImpl() override = default;
LatencyGeneratorImpl(double average_latency, int32_t seed)
: gen_(static_cast<decltype(gen_)::result_type>(seed)),
latency_dist_(average_latency, average_latency * kStandardDeviationRatio) {}
double NextLatency() override {
// std::random distributions are unlikely to be thread-safe, and
// a RandomAccessFile may be called from multiple threads
std::lock_guard<std::mutex> lock(mutex_);
return std::max<double>(0.0, latency_dist_(gen_));
}
private:
std::default_random_engine gen_;
std::normal_distribution<double> latency_dist_;
std::mutex mutex_;
};
LatencyGenerator::~LatencyGenerator() {}
void LatencyGenerator::Sleep() {
std::this_thread::sleep_for(std::chrono::duration<double>(NextLatency()));
}
std::shared_ptr<LatencyGenerator> LatencyGenerator::Make(double average_latency) {
return std::make_shared<LatencyGeneratorImpl>(
average_latency, static_cast<int32_t>(::arrow20::internal::GetRandomSeed()));
}
std::shared_ptr<LatencyGenerator> LatencyGenerator::Make(double average_latency,
int32_t seed) {
return std::make_shared<LatencyGeneratorImpl>(average_latency, seed);
}
//////////////////////////////////////////////////////////////////////////
// SlowInputStream implementation
SlowInputStream::~SlowInputStream() { internal::CloseFromDestructor(this); }
Status SlowInputStream::Close() { return stream_->Close(); }
Status SlowInputStream::Abort() { return stream_->Abort(); }
bool SlowInputStream::closed() const { return stream_->closed(); }
Result<int64_t> SlowInputStream::Tell() const { return stream_->Tell(); }
Result<int64_t> SlowInputStream::Read(int64_t nbytes, void* out) {
latencies_->Sleep();
return stream_->Read(nbytes, out);
}
Result<std::shared_ptr<Buffer>> SlowInputStream::Read(int64_t nbytes) {
latencies_->Sleep();
return stream_->Read(nbytes);
}
Result<std::string_view> SlowInputStream::Peek(int64_t nbytes) {
return stream_->Peek(nbytes);
}
//////////////////////////////////////////////////////////////////////////
// SlowRandomAccessFile implementation
SlowRandomAccessFile::~SlowRandomAccessFile() { internal::CloseFromDestructor(this); }
Status SlowRandomAccessFile::Close() { return stream_->Close(); }
Status SlowRandomAccessFile::Abort() { return stream_->Abort(); }
bool SlowRandomAccessFile::closed() const { return stream_->closed(); }
Result<int64_t> SlowRandomAccessFile::GetSize() { return stream_->GetSize(); }
Status SlowRandomAccessFile::Seek(int64_t position) { return stream_->Seek(position); }
Result<int64_t> SlowRandomAccessFile::Tell() const { return stream_->Tell(); }
Result<int64_t> SlowRandomAccessFile::Read(int64_t nbytes, void* out) {
latencies_->Sleep();
return stream_->Read(nbytes, out);
}
Result<std::shared_ptr<Buffer>> SlowRandomAccessFile::Read(int64_t nbytes) {
latencies_->Sleep();
return stream_->Read(nbytes);
}
Result<int64_t> SlowRandomAccessFile::ReadAt(int64_t position, int64_t nbytes,
void* out) {
latencies_->Sleep();
return stream_->ReadAt(position, nbytes, out);
}
Result<std::shared_ptr<Buffer>> SlowRandomAccessFile::ReadAt(int64_t position,
int64_t nbytes) {
latencies_->Sleep();
return stream_->ReadAt(position, nbytes);
}
Result<std::string_view> SlowRandomAccessFile::Peek(int64_t nbytes) {
return stream_->Peek(nbytes);
}
} // namespace io
} // namespace arrow20
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