6e9fbeb27c
Summary: We want to keep Env a think layer for better portability. Less platform dependent codes should be moved out of Env. In this patch, I create a wrapper of file readers and writers, and put rate limiting, write buffering, as well as most perf context instrumentation and random kill out of Env. It will make it easier to maintain multiple Env in the future. Test Plan: Run all existing unit tests. Reviewers: anthony, kradhakrishnan, IslamAbdelRahman, yhchiang, igor Reviewed By: igor Subscribers: leveldb, dhruba Differential Revision: https://reviews.facebook.net/D42321
68 lines
1.8 KiB
C++
68 lines
1.8 KiB
C++
// Copyright (c) 2013, Facebook, Inc. All rights reserved.
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// This source code is licensed under the BSD-style license found in the
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// LICENSE file in the root directory of this source tree. An additional grant
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// of patent rights can be found in the PATENTS file in the same directory.
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//
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#include <string>
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#include <algorithm>
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#include "util/file_util.h"
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#include "rocksdb/env.h"
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#include "db/filename.h"
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#include "util/file_reader_writer.h"
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namespace rocksdb {
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// Utility function to copy a file up to a specified length
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Status CopyFile(Env* env, const std::string& source,
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const std::string& destination, uint64_t size) {
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const EnvOptions soptions;
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Status s;
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unique_ptr<SequentialFileReader> src_reader;
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unique_ptr<WritableFileWriter> dest_writer;
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{
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unique_ptr<SequentialFile> srcfile;
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s = env->NewSequentialFile(source, &srcfile, soptions);
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unique_ptr<WritableFile> destfile;
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if (s.ok()) {
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s = env->NewWritableFile(destination, &destfile, soptions);
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} else {
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return s;
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}
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if (size == 0) {
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// default argument means copy everything
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if (s.ok()) {
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s = env->GetFileSize(source, &size);
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} else {
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return s;
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}
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}
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src_reader.reset(new SequentialFileReader(std::move(srcfile)));
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dest_writer.reset(new WritableFileWriter(std::move(destfile), soptions));
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}
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char buffer[4096];
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Slice slice;
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while (size > 0) {
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uint64_t bytes_to_read =
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std::min(static_cast<uint64_t>(sizeof(buffer)), size);
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if (s.ok()) {
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s = src_reader->Read(bytes_to_read, &slice, buffer);
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}
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if (s.ok()) {
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if (slice.size() == 0) {
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return Status::Corruption("file too small");
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}
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s = dest_writer->Append(slice);
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}
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if (!s.ok()) {
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return s;
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}
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size -= slice.size();
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}
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return Status::OK();
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}
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} // namespace rocksdb
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