mirror of https://github.com/facebook/rocksdb.git
74 lines
2.3 KiB
C++
74 lines
2.3 KiB
C++
// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
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// This source code is licensed under both the GPLv2 (found in the
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// COPYING file in the root directory) and Apache 2.0 License
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// (found in the LICENSE.Apache file in the root directory).
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#include "file/line_file_reader.h"
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#include <cstring>
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#include "monitoring/iostats_context_imp.h"
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namespace ROCKSDB_NAMESPACE {
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IOStatus LineFileReader::Create(const std::shared_ptr<FileSystem>& fs,
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const std::string& fname,
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const FileOptions& file_opts,
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std::unique_ptr<LineFileReader>* reader,
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IODebugContext* dbg,
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RateLimiter* rate_limiter) {
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std::unique_ptr<FSSequentialFile> file;
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IOStatus io_s = fs->NewSequentialFile(fname, file_opts, &file, dbg);
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if (io_s.ok()) {
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reader->reset(new LineFileReader(
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std::move(file), fname, nullptr,
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std::vector<std::shared_ptr<EventListener>>{}, rate_limiter));
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}
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return io_s;
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}
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bool LineFileReader::ReadLine(std::string* out,
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Env::IOPriority rate_limiter_priority) {
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assert(out);
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if (!io_status_.ok()) {
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// Status should be checked (or permit unchecked) any time we return false.
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io_status_.MustCheck();
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return false;
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}
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out->clear();
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for (;;) {
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// Look for line delimiter
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const char* found = static_cast<const char*>(
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std::memchr(buf_begin_, '\n', buf_end_ - buf_begin_));
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if (found) {
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size_t len = found - buf_begin_;
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out->append(buf_begin_, len);
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buf_begin_ += len + /*delim*/ 1;
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++line_number_;
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return true;
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}
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if (at_eof_) {
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io_status_.MustCheck();
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return false;
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}
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// else flush and reload buffer
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out->append(buf_begin_, buf_end_ - buf_begin_);
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Slice result;
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io_status_ =
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sfr_.Read(buf_.size(), &result, buf_.data(), rate_limiter_priority);
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IOSTATS_ADD(bytes_read, result.size());
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if (!io_status_.ok()) {
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io_status_.MustCheck();
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return false;
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}
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if (result.size() != buf_.size()) {
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// The obscure way of indicating EOF
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at_eof_ = true;
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}
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buf_begin_ = result.data();
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buf_end_ = result.data() + result.size();
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}
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}
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} // namespace ROCKSDB_NAMESPACE
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