rocksdb/util/file_util.cc
Venkatesh Radhakrishnan 6c1b040cc9 Provide openable snapshots
Summary: Store links to live files in directory on same disk

Test Plan:
Take snapshot and open it. Added a test GetSnapshotLink in
db_test.

Reviewers: sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D28713
2014-11-14 11:38:26 -08:00

60 lines
1.5 KiB
C++

// Copyright (c) 2013, Facebook, Inc. All rights reserved.
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree. An additional grant
// of patent rights can be found in the PATENTS file in the same directory.
//
#include <string>
#include <algorithm>
#include "util/file_util.h"
#include "rocksdb/env.h"
#include "db/filename.h"
namespace rocksdb {
// Utility function to copy a file up to a specified length
Status CopyFile(Env* env, const std::string& source,
const std::string& destination, uint64_t size) {
const EnvOptions soptions;
unique_ptr<SequentialFile> srcfile;
Status s;
s = env->NewSequentialFile(source, &srcfile, soptions);
unique_ptr<WritableFile> destfile;
if (s.ok()) {
s = env->NewWritableFile(destination, &destfile, soptions);
} else {
return s;
}
if (size == 0) {
// default argument means copy everything
if (s.ok()) {
s = env->GetFileSize(source, &size);
} else {
return s;
}
}
char buffer[4096];
Slice slice;
while (size > 0) {
uint64_t bytes_to_read =
std::min(static_cast<uint64_t>(sizeof(buffer)), size);
if (s.ok()) {
s = srcfile->Read(bytes_to_read, &slice, buffer);
}
if (s.ok()) {
if (slice.size() == 0) {
return Status::Corruption("file too small");
}
s = destfile->Append(slice);
}
if (!s.ok()) {
return s;
}
size -= slice.size();
}
return Status::OK();
}
} // namespace rocksdb