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rocksdb/file/file_util.cc

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// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
//
#include "file/file_util.h"
#include <string>
#include <algorithm>
#include "file/random_access_file_reader.h"
#include "file/sequence_file_reader.h"
#include "file/sst_file_manager_impl.h"
#include "file/writable_file_writer.h"
#include "rocksdb/env.h"
namespace ROCKSDB_NAMESPACE {
// Utility function to copy a file up to a specified length
IOStatus CopyFile(FileSystem* fs, const std::string& source,
const std::string& destination, uint64_t size, bool use_fsync,
const std::shared_ptr<IOTracer>& io_tracer,
const Temperature temperature) {
FileOptions soptions;
IOStatus io_s;
std::unique_ptr<SequentialFileReader> src_reader;
std::unique_ptr<WritableFileWriter> dest_writer;
{
soptions.temperature = temperature;
std::unique_ptr<FSSequentialFile> srcfile;
io_s = fs->NewSequentialFile(source, soptions, &srcfile, nullptr);
if (!io_s.ok()) {
return io_s;
}
std::unique_ptr<FSWritableFile> destfile;
io_s = fs->NewWritableFile(destination, soptions, &destfile, nullptr);
if (!io_s.ok()) {
return io_s;
}
if (size == 0) {
// default argument means copy everything
io_s = fs->GetFileSize(source, IOOptions(), &size, nullptr);
if (!io_s.ok()) {
return io_s;
}
}
src_reader.reset(
new SequentialFileReader(std::move(srcfile), source, io_tracer));
dest_writer.reset(
new WritableFileWriter(std::move(destfile), destination, soptions));
}
char buffer[4096];
Slice slice;
while (size > 0) {
size_t bytes_to_read = std::min(sizeof(buffer), static_cast<size_t>(size));
io_s = status_to_io_status(src_reader->Read(bytes_to_read, &slice, buffer));
if (!io_s.ok()) {
return io_s;
}
if (slice.size() == 0) {
return IOStatus::Corruption("file too small");
}
io_s = dest_writer->Append(slice);
if (!io_s.ok()) {
return io_s;
}
size -= slice.size();
}
return dest_writer->Sync(use_fsync);
}
// Utility function to create a file with the provided contents
IOStatus CreateFile(FileSystem* fs, const std::string& destination,
const std::string& contents, bool use_fsync) {
const EnvOptions soptions;
IOStatus io_s;
std::unique_ptr<WritableFileWriter> dest_writer;
std::unique_ptr<FSWritableFile> destfile;
io_s = fs->NewWritableFile(destination, soptions, &destfile, nullptr);
if (!io_s.ok()) {
return io_s;
}
dest_writer.reset(
new WritableFileWriter(std::move(destfile), destination, soptions));
io_s = dest_writer->Append(Slice(contents));
if (!io_s.ok()) {
return io_s;
}
return dest_writer->Sync(use_fsync);
}
Status DeleteDBFile(const ImmutableDBOptions* db_options,
const std::string& fname, const std::string& dir_to_sync,
const bool force_bg, const bool force_fg) {
#ifndef ROCKSDB_LITE
SstFileManagerImpl* sfm =
static_cast<SstFileManagerImpl*>(db_options->sst_file_manager.get());
if (sfm && !force_fg) {
return sfm->ScheduleFileDeletion(fname, dir_to_sync, force_bg);
} else {
return db_options->env->DeleteFile(fname);
}
#else
(void)dir_to_sync;
(void)force_bg;
(void)force_fg;
// SstFileManager is not supported in ROCKSDB_LITE
// Delete file immediately
return db_options->env->DeleteFile(fname);
#endif
}
// requested_checksum_func_name brings the function name of the checksum
// generator in checksum_factory. Empty string is permitted, in which case the
// name of the generator created by the factory is unchecked. When
// `requested_checksum_func_name` is non-empty, however, the created generator's
// name must match it, otherwise an `InvalidArgument` error is returned.
IOStatus GenerateOneFileChecksum(
FileSystem* fs, const std::string& file_path,
FileChecksumGenFactory* checksum_factory,
const std::string& requested_checksum_func_name, std::string* file_checksum,
std::string* file_checksum_func_name,
size_t verify_checksums_readahead_size, bool allow_mmap_reads,
std::shared_ptr<IOTracer>& io_tracer, RateLimiter* rate_limiter,
Env::IOPriority rate_limiter_priority) {
if (checksum_factory == nullptr) {
return IOStatus::InvalidArgument("Checksum factory is invalid");
}
assert(file_checksum != nullptr);
assert(file_checksum_func_name != nullptr);
FileChecksumGenContext gen_context;
gen_context.requested_checksum_func_name = requested_checksum_func_name;
gen_context.file_name = file_path;
std::unique_ptr<FileChecksumGenerator> checksum_generator =
checksum_factory->CreateFileChecksumGenerator(gen_context);
if (checksum_generator == nullptr) {
std::string msg =
"Cannot get the file checksum generator based on the requested "
"checksum function name: " +
requested_checksum_func_name +
" from checksum factory: " + checksum_factory->Name();
return IOStatus::InvalidArgument(msg);
} else {
// For backward compatibility and use in file ingestion clients where there
// is no stored checksum function name, `requested_checksum_func_name` can
// be empty. If we give the requested checksum function name, we expect it
// is the same name of the checksum generator.
if (!requested_checksum_func_name.empty() &&
checksum_generator->Name() != requested_checksum_func_name) {
std::string msg = "Expected file checksum generator named '" +
requested_checksum_func_name +
"', while the factory created one "
"named '" +
checksum_generator->Name() + "'";
return IOStatus::InvalidArgument(msg);
}
}
uint64_t size;
IOStatus io_s;
std::unique_ptr<RandomAccessFileReader> reader;
{
std::unique_ptr<FSRandomAccessFile> r_file;
io_s = fs->NewRandomAccessFile(file_path, FileOptions(), &r_file, nullptr);
if (!io_s.ok()) {
return io_s;
}
io_s = fs->GetFileSize(file_path, IOOptions(), &size, nullptr);
if (!io_s.ok()) {
return io_s;
}
reader.reset(new RandomAccessFileReader(std::move(r_file), file_path,
nullptr /*Env*/, io_tracer, nullptr,
0, nullptr, rate_limiter));
}
// Found that 256 KB readahead size provides the best performance, based on
// experiments, for auto readahead. Experiment data is in PR #3282.
size_t default_max_read_ahead_size = 256 * 1024;
size_t readahead_size = (verify_checksums_readahead_size != 0)
? verify_checksums_readahead_size
: default_max_read_ahead_size;
FilePrefetchBuffer prefetch_buffer(readahead_size /* readahead_size */,
readahead_size /* max_readahead_size */,
!allow_mmap_reads /* enable */);
Slice slice;
uint64_t offset = 0;
IOOptions opts;
while (size > 0) {
size_t bytes_to_read =
static_cast<size_t>(std::min(uint64_t{readahead_size}, size));
if (!prefetch_buffer.TryReadFromCache(
opts, reader.get(), offset, bytes_to_read, &slice,
nullptr /* status */, rate_limiter_priority,
false /* for_compaction */)) {
return IOStatus::Corruption("file read failed");
}
if (slice.size() == 0) {
return IOStatus::Corruption("file too small");
}
checksum_generator->Update(slice.data(), slice.size());
size -= slice.size();
offset += slice.size();
}
checksum_generator->Finalize();
*file_checksum = checksum_generator->GetChecksum();
*file_checksum_func_name = checksum_generator->Name();
return IOStatus::OK();
}
Status DestroyDir(Env* env, const std::string& dir) {
Status s;
if (env->FileExists(dir).IsNotFound()) {
return s;
}
std::vector<std::string> files_in_dir;
s = env->GetChildren(dir, &files_in_dir);
if (s.ok()) {
for (auto& file_in_dir : files_in_dir) {
std::string path = dir + "/" + file_in_dir;
bool is_dir = false;
s = env->IsDirectory(path, &is_dir);
if (s.ok()) {
if (is_dir) {
s = DestroyDir(env, path);
} else {
s = env->DeleteFile(path);
}
} else if (s.IsNotSupported()) {
s = Status::OK();
}
if (!s.ok()) {
// IsDirectory, etc. might not report NotFound
if (s.IsNotFound() || env->FileExists(path).IsNotFound()) {
// Allow files to be deleted externally
s = Status::OK();
} else {
break;
}
}
}
}
if (s.ok()) {
s = env->DeleteDir(dir);
// DeleteDir might or might not report NotFound
if (!s.ok() && (s.IsNotFound() || env->FileExists(dir).IsNotFound())) {
// Allow to be deleted externally
s = Status::OK();
}
}
return s;
}
} // namespace ROCKSDB_NAMESPACE