Files
netris-cdc-file-transfer/common/file_watcher_win.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

112 lines
3.8 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 COMMON_FILE_WATCHER_WIN_H_
#define COMMON_FILE_WATCHER_WIN_H_
#define WIN32_LEAN_AND_MEAN
#include <string>
#include <unordered_map>
#include "absl/base/thread_annotations.h"
#include "absl/status/status.h"
#include "absl/synchronization/mutex.h"
namespace cdc_ft {
class AsyncFileWatcher;
// FileWatcherWin observes changes done in a specific directory on Windows.
class FileWatcherWin {
public:
// Default timeout in milliseconds.
static constexpr unsigned int kFileWatcherTimeoutMs = 1000;
using FilesChangedCb = std::function<void()>;
using DirRecreatedCb = std::function<void()>;
enum class FileAction { kAdded, kModified, kDeleted };
struct FileInfo {
FileAction action;
bool is_dir;
uint64_t size;
int64_t mtime;
FileInfo(FileAction action, bool is_dir, uint64_t size, int64_t mtime)
: action(action), is_dir(is_dir), size(size), mtime(mtime) {}
};
using FileMap = std::unordered_map<std::string, FileInfo>;
explicit FileWatcherWin(std::string directory);
FileWatcherWin(const FileWatcherWin& other) = delete;
FileWatcherWin& operator=(const FileWatcherWin& other) = delete;
~FileWatcherWin();
// Returns a map that maps relative paths of modified files to their file
// attributes.
FileMap GetModifiedFiles() ABSL_LOCKS_EXCLUDED(modified_files_mutex_);
// Starts watching directory changes.
// |files_changed_cb| is called on a background thread whenever files changed.
// |dir_recreated_cb| is called on a background thread whenever the watched
// directory was removed/created/re-created. It does not guarantee that the
// watched directory exists. The caller should check on its own and handle
// a case if the directory still does not exist. The callback shows that all
// outstanding changes are not valid anymore.
// |timeout_ms| is a timeout in ms for a change in the watched directory.
absl::Status StartWatching(FilesChangedCb files_changed_cb = FilesChangedCb(),
DirRecreatedCb dir_recreated_cb = DirRecreatedCb(),
unsigned int timeout_ms = kFileWatcherTimeoutMs);
// Stops watching directory changes.
absl::Status StopWatching() ABSL_LOCKS_EXCLUDED(modified_files_mutex_);
// Indicates whether a directory is currently watched.
bool IsWatching() const;
// Returns the watching status.
absl::Status GetStatus() const;
// Returns the total file changed events received so far.
// Returns 0 if the watcher is currently in stopped state.
uint32_t GetEventCountForTesting() const;
// Returns the total number of events for the directory changes received so
// far. Returns 0 if the watcher is currently in stopped state.
uint32_t GetDirRecreateEventCountForTesting() const;
// Enforces the use of ReadDirectoryChanges instead of ReadDirectoryChangesEx.
// Must be called before StartWatching.
void EnforceLegacyReadDirectoryChangesForTesting();
private:
std::string dir_path_;
std::unique_ptr<AsyncFileWatcher> async_watcher_;
absl::Mutex modified_files_mutex_;
FileMap modified_files_ ABSL_GUARDED_BY(modified_files_mutex_);
bool enforceLegacyReadDirectoryChangesForTesting_ = false;
};
} // namespace cdc_ft
#endif // COMMON_FILE_WATCHER_WIN_H_