1 files changed, 343 insertions, 0 deletions
diff --git a/src/rocksdb/env/fs_remap.cc b/src/rocksdb/env/fs_remap.cc
new file mode 100644
index 000000000..fd9241181
--- /dev/null
+++ b/src/rocksdb/env/fs_remap.cc
@@ -0,0 +1,343 @@
+//  Copyright (c) Facebook, Inc. and its affiliates. 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).
+
+#ifndef ROCKSDB_LITE
+
+#include "env/fs_remap.h"
+
+namespace ROCKSDB_NAMESPACE {
+
+RemapFileSystem::RemapFileSystem(const std::shared_ptr<FileSystem>& base)
+    : FileSystemWrapper(base) {}
+
+std::pair<IOStatus, std::string> RemapFileSystem::EncodePathWithNewBasename(
+    const std::string& path) {
+  // No difference by default
+  return EncodePath(path);
+}
+
+Status RemapFileSystem::RegisterDbPaths(const std::vector<std::string>& paths) {
+  std::vector<std::string> encoded_paths;
+  encoded_paths.reserve(paths.size());
+  for (auto& path : paths) {
+    auto status_and_enc_path = EncodePathWithNewBasename(path);
+    if (!status_and_enc_path.first.ok()) {
+      return status_and_enc_path.first;
+    }
+    encoded_paths.emplace_back(status_and_enc_path.second);
+  }
+  return FileSystemWrapper::RegisterDbPaths(encoded_paths);
+}
+
+Status RemapFileSystem::UnregisterDbPaths(
+    const std::vector<std::string>& paths) {
+  std::vector<std::string> encoded_paths;
+  encoded_paths.reserve(paths.size());
+  for (auto& path : paths) {
+    auto status_and_enc_path = EncodePathWithNewBasename(path);
+    if (!status_and_enc_path.first.ok()) {
+      return status_and_enc_path.first;
+    }
+    encoded_paths.emplace_back(status_and_enc_path.second);
+  }
+  return FileSystemWrapper::UnregisterDbPaths(encoded_paths);
+}
+
+IOStatus RemapFileSystem::NewSequentialFile(
+    const std::string& fname, const FileOptions& options,
+    std::unique_ptr<FSSequentialFile>* result, IODebugContext* dbg) {
+  auto status_and_enc_path = EncodePathWithNewBasename(fname);
+  if (!status_and_enc_path.first.ok()) {
+    return status_and_enc_path.first;
+  }
+  return FileSystemWrapper::NewSequentialFile(status_and_enc_path.second,
+                                              options, result, dbg);
+}
+
+IOStatus RemapFileSystem::NewRandomAccessFile(
+    const std::string& fname, const FileOptions& options,
+    std::unique_ptr<FSRandomAccessFile>* result, IODebugContext* dbg) {
+  auto status_and_enc_path = EncodePathWithNewBasename(fname);
+  if (!status_and_enc_path.first.ok()) {
+    return status_and_enc_path.first;
+  }
+  return FileSystemWrapper::NewRandomAccessFile(status_and_enc_path.second,
+                                                options, result, dbg);
+}
+
+IOStatus RemapFileSystem::NewWritableFile(
+    const std::string& fname, const FileOptions& options,
+    std::unique_ptr<FSWritableFile>* result, IODebugContext* dbg) {
+  auto status_and_enc_path = EncodePathWithNewBasename(fname);
+  if (!status_and_enc_path.first.ok()) {
+    return status_and_enc_path.first;
+  }
+  return FileSystemWrapper::NewWritableFile(status_and_enc_path.second, options,
+                                            result, dbg);
+}
+
+IOStatus RemapFileSystem::ReuseWritableFile(
+    const std::string& fname, const std::string& old_fname,
+    const FileOptions& options, std::unique_ptr<FSWritableFile>* result,
+    IODebugContext* dbg) {
+  auto status_and_enc_path = EncodePathWithNewBasename(fname);
+  if (!status_and_enc_path.first.ok()) {
+    return status_and_enc_path.first;
+  }
+  auto status_and_old_enc_path = EncodePath(old_fname);
+  if (!status_and_old_enc_path.first.ok()) {
+    return status_and_old_enc_path.first;
+  }
+  return FileSystemWrapper::ReuseWritableFile(status_and_old_enc_path.second,
+                                              status_and_old_enc_path.second,
+                                              options, result, dbg);
+}
+
+IOStatus RemapFileSystem::NewRandomRWFile(
+    const std::string& fname, const FileOptions& options,
+    std::unique_ptr<FSRandomRWFile>* result, IODebugContext* dbg) {
+  auto status_and_enc_path = EncodePathWithNewBasename(fname);
+  if (!status_and_enc_path.first.ok()) {
+    return status_and_enc_path.first;
+  }
+  return FileSystemWrapper::NewRandomRWFile(status_and_enc_path.second, options,
+                                            result, dbg);
+}
+
+IOStatus RemapFileSystem::NewDirectory(const std::string& dir,
+                                       const IOOptions& options,
+                                       std::unique_ptr<FSDirectory>* result,
+                                       IODebugContext* dbg) {
+  // A hassle to remap DirFsyncOptions::renamed_new_name
+  class RemapFSDirectory : public FSDirectoryWrapper {
+   public:
+    RemapFSDirectory(RemapFileSystem* fs, std::unique_ptr<FSDirectory>&& t)
+        : FSDirectoryWrapper(std::move(t)), fs_(fs) {}
+    IOStatus FsyncWithDirOptions(
+        const IOOptions& options, IODebugContext* dbg,
+        const DirFsyncOptions& dir_fsync_options) override {
+      if (dir_fsync_options.renamed_new_name.empty()) {
+        return FSDirectoryWrapper::FsyncWithDirOptions(options, dbg,
+                                                       dir_fsync_options);
+      } else {
+        auto status_and_enc_path =
+            fs_->EncodePath(dir_fsync_options.renamed_new_name);
+        if (status_and_enc_path.first.ok()) {
+          DirFsyncOptions mapped_options = dir_fsync_options;
+          mapped_options.renamed_new_name = status_and_enc_path.second;
+          return FSDirectoryWrapper::FsyncWithDirOptions(options, dbg,
+                                                         mapped_options);
+        } else {
+          return status_and_enc_path.first;
+        }
+      }
+    }
+
+   private:
+    RemapFileSystem* const fs_;
+  };
+
+  auto status_and_enc_path = EncodePathWithNewBasename(dir);
+  if (!status_and_enc_path.first.ok()) {
+    return status_and_enc_path.first;
+  }
+  IOStatus ios = FileSystemWrapper::NewDirectory(status_and_enc_path.second,
+                                                 options, result, dbg);
+  if (ios.ok()) {
+    *result = std::make_unique<RemapFSDirectory>(this, std::move(*result));
+  }
+  return ios;
+}
+
+IOStatus RemapFileSystem::FileExists(const std::string& fname,
+                                     const IOOptions& options,
+                                     IODebugContext* dbg) {
+  auto status_and_enc_path = EncodePathWithNewBasename(fname);
+  if (!status_and_enc_path.first.ok()) {
+    return status_and_enc_path.first;
+  }
+  return FileSystemWrapper::FileExists(status_and_enc_path.second, options,
+                                       dbg);
+}
+
+IOStatus RemapFileSystem::GetChildren(const std::string& dir,
+                                      const IOOptions& options,
+                                      std::vector<std::string>* result,
+                                      IODebugContext* dbg) {
+  auto status_and_enc_path = EncodePath(dir);
+  if (!status_and_enc_path.first.ok()) {
+    return status_and_enc_path.first;
+  }
+  return FileSystemWrapper::GetChildren(status_and_enc_path.second, options,
+                                        result, dbg);
+}
+
+IOStatus RemapFileSystem::GetChildrenFileAttributes(
+    const std::string& dir, const IOOptions& options,
+    std::vector<FileAttributes>* result, IODebugContext* dbg) {
+  auto status_and_enc_path = EncodePath(dir);
+  if (!status_and_enc_path.first.ok()) {
+    return status_and_enc_path.first;
+  }
+  return FileSystemWrapper::GetChildrenFileAttributes(
+      status_and_enc_path.second, options, result, dbg);
+}
+
+IOStatus RemapFileSystem::DeleteFile(const std::string& fname,
+                                     const IOOptions& options,
+                                     IODebugContext* dbg) {
+  auto status_and_enc_path = EncodePath(fname);
+  if (!status_and_enc_path.first.ok()) {
+    return status_and_enc_path.first;
+  }
+  return FileSystemWrapper::DeleteFile(status_and_enc_path.second, options,
+                                       dbg);
+}
+
+IOStatus RemapFileSystem::CreateDir(const std::string& dirname,
+                                    const IOOptions& options,
+                                    IODebugContext* dbg) {
+  auto status_and_enc_path = EncodePathWithNewBasename(dirname);
+  if (!status_and_enc_path.first.ok()) {
+    return status_and_enc_path.first;
+  }
+  return FileSystemWrapper::CreateDir(status_and_enc_path.second, options, dbg);
+}
+
+IOStatus RemapFileSystem::CreateDirIfMissing(const std::string& dirname,
+                                             const IOOptions& options,
+                                             IODebugContext* dbg) {
+  auto status_and_enc_path = EncodePathWithNewBasename(dirname);
+  if (!status_and_enc_path.first.ok()) {
+    return status_and_enc_path.first;
+  }
+  return FileSystemWrapper::CreateDirIfMissing(status_and_enc_path.second,
+                                               options, dbg);
+}
+
+IOStatus RemapFileSystem::DeleteDir(const std::string& dirname,
+                                    const IOOptions& options,
+                                    IODebugContext* dbg) {
+  auto status_and_enc_path = EncodePath(dirname);
+  if (!status_and_enc_path.first.ok()) {
+    return status_and_enc_path.first;
+  }
+  return FileSystemWrapper::DeleteDir(status_and_enc_path.second, options, dbg);
+}
+
+IOStatus RemapFileSystem::GetFileSize(const std::string& fname,
+                                      const IOOptions& options,
+                                      uint64_t* file_size,
+                                      IODebugContext* dbg) {
+  auto status_and_enc_path = EncodePath(fname);
+  if (!status_and_enc_path.first.ok()) {
+    return status_and_enc_path.first;
+  }
+  return FileSystemWrapper::GetFileSize(status_and_enc_path.second, options,
+                                        file_size, dbg);
+}
+
+IOStatus RemapFileSystem::GetFileModificationTime(const std::string& fname,
+                                                  const IOOptions& options,
+                                                  uint64_t* file_mtime,
+                                                  IODebugContext* dbg) {
+  auto status_and_enc_path = EncodePath(fname);
+  if (!status_and_enc_path.first.ok()) {
+    return status_and_enc_path.first;
+  }
+  return FileSystemWrapper::GetFileModificationTime(status_and_enc_path.second,
+                                                    options, file_mtime, dbg);
+}
+
+IOStatus RemapFileSystem::IsDirectory(const std::string& path,
+                                      const IOOptions& options, bool* is_dir,
+                                      IODebugContext* dbg) {
+  auto status_and_enc_path = EncodePath(path);
+  if (!status_and_enc_path.first.ok()) {
+    return status_and_enc_path.first;
+  }
+  return FileSystemWrapper::IsDirectory(status_and_enc_path.second, options,
+                                        is_dir, dbg);
+}
+
+IOStatus RemapFileSystem::RenameFile(const std::string& src,
+                                     const std::string& dest,
+                                     const IOOptions& options,
+                                     IODebugContext* dbg) {
+  auto status_and_src_enc_path = EncodePath(src);
+  if (!status_and_src_enc_path.first.ok()) {
+    if (status_and_src_enc_path.first.IsNotFound()) {
+      const IOStatus& s = status_and_src_enc_path.first;
+      status_and_src_enc_path.first = IOStatus::PathNotFound(s.ToString());
+    }
+    return status_and_src_enc_path.first;
+  }
+  auto status_and_dest_enc_path = EncodePathWithNewBasename(dest);
+  if (!status_and_dest_enc_path.first.ok()) {
+    return status_and_dest_enc_path.first;
+  }
+  return FileSystemWrapper::RenameFile(status_and_src_enc_path.second,
+                                       status_and_dest_enc_path.second, options,
+                                       dbg);
+}
+
+IOStatus RemapFileSystem::LinkFile(const std::string& src,
+                                   const std::string& dest,
+                                   const IOOptions& options,
+                                   IODebugContext* dbg) {
+  auto status_and_src_enc_path = EncodePath(src);
+  if (!status_and_src_enc_path.first.ok()) {
+    return status_and_src_enc_path.first;
+  }
+  auto status_and_dest_enc_path = EncodePathWithNewBasename(dest);
+  if (!status_and_dest_enc_path.first.ok()) {
+    return status_and_dest_enc_path.first;
+  }
+  return FileSystemWrapper::LinkFile(status_and_src_enc_path.second,
+                                     status_and_dest_enc_path.second, options,
+                                     dbg);
+}
+
+IOStatus RemapFileSystem::LockFile(const std::string& fname,
+                                   const IOOptions& options, FileLock** lock,
+                                   IODebugContext* dbg) {
+  auto status_and_enc_path = EncodePathWithNewBasename(fname);
+  if (!status_and_enc_path.first.ok()) {
+    return status_and_enc_path.first;
+  }
+  // FileLock subclasses may store path (e.g., PosixFileLock stores it). We
+  // can skip stripping the chroot directory from this path because callers
+  // shouldn't use it.
+  return FileSystemWrapper::LockFile(status_and_enc_path.second, options, lock,
+                                     dbg);
+}
+
+IOStatus RemapFileSystem::NewLogger(const std::string& fname,
+                                    const IOOptions& options,
+                                    std::shared_ptr<Logger>* result,
+                                    IODebugContext* dbg) {
+  auto status_and_enc_path = EncodePathWithNewBasename(fname);
+  if (!status_and_enc_path.first.ok()) {
+    return status_and_enc_path.first;
+  }
+  return FileSystemWrapper::NewLogger(status_and_enc_path.second, options,
+                                      result, dbg);
+}
+
+IOStatus RemapFileSystem::GetAbsolutePath(const std::string& db_path,
+                                          const IOOptions& options,
+                                          std::string* output_path,
+                                          IODebugContext* dbg) {
+  auto status_and_enc_path = EncodePathWithNewBasename(db_path);
+  if (!status_and_enc_path.first.ok()) {
+    return status_and_enc_path.first;
+  }
+  return FileSystemWrapper::GetAbsolutePath(status_and_enc_path.second, options,
+                                            output_path, dbg);
+}
+
+}  // namespace ROCKSDB_NAMESPACE
+
+#endif  // ROCKSDB_LITE