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netris-cdc-file-transfer/cdc_rsync/parallel_file_opener.h
Christian Schneider 4326e972ac Releasing the former Stadia file transfer tools
The tools allow efficient and fast synchronization of large directory
trees from a Windows workstation to a Linux target machine.

cdc_rsync* support efficient copy of files by using content-defined
chunking (CDC) to identify chunks within files that can be reused.

asset_stream_manager + cdc_fuse_fs support efficient streaming of a
local directory to a remote virtual file system based on FUSE. It also
employs CDC to identify and reuse unchanged data chunks.
2022-11-03 10:39:10 +01:00

75 lines
2.2 KiB
C++

/*
* Copyright 2022 Google LLC
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef CDC_RSYNC_PARALLEL_FILE_OPENER_H_
#define CDC_RSYNC_PARALLEL_FILE_OPENER_H_
#include <map>
#include <memory>
#include <vector>
#include "cdc_rsync/client_file_info.h"
#include "common/threadpool.h"
namespace cdc_ft {
namespace internal {
class FileOpenTask;
}
// Opens files on a background worker thread pool. This improves performance in
// cases where many files have to be opened quickly.
class ParallelFileOpener {
public:
// Starts opening the |files| indexed by |file_indices| in the background.
ParallelFileOpener(const std::vector<ClientFileInfo>* files,
const std::vector<uint32_t>& file_indices);
~ParallelFileOpener();
// Returns FILE* pointer from opening a file from |files| in rb-mode.
// The first call returns the FILE* pointer for files[file_indices[0]],
// the second call returns the FILE* pointer for files[file_indices[1]] etc.
// The caller must close the file.
FILE* GetNextOpenFile();
private:
// Queues another open file task.
void QueueNextFile();
// Pointer to list of files, not owned.
const std::vector<ClientFileInfo>* files_;
// Indices into the |files_| to open.
std::vector<uint32_t> file_indices_;
// Index into |file_indices_| of the next file returned by GetNextOpenFile().
size_t curr_index_ = 0;
// Index into |file_indices_| of the file queued by QueueNextFile().
size_t look_ahead_index_ = 0;
// Maps index into |file_indices_| to completed task.
std::map<size_t, std::unique_ptr<internal::FileOpenTask>>
index_to_completed_tasks_;
Threadpool pool_;
};
} // namespace cdc_ft
#endif // CDC_RSYNC_PARALLEL_FILE_OPENER_H_