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.

cdc_rsync_server/file_finder.h

@@ -0,0 +1,53 @@
+/*
+ * 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_SERVER_FILE_FINDER_H_
+#define CDC_RSYNC_SERVER_FILE_FINDER_H_
+
+#include <vector>
+
+#include "absl/status/status.h"
+#include "cdc_rsync_server/file_info.h"
+
+namespace cdc_ft {
+
+class PathFilter;
+
+// Scans directories and gathers contained files and directories.
+class FileFinder {
+ public:
+  FileFinder();
+  ~FileFinder();
+
+  // Gathers files and directories in |base_dir|. If |recursive| is true,
+  // searches recursively. |path_filter| is used to filter files and
+  // directories.
+  // If subsequent calls to AddFiles find a file or directory with the same
+  // relative path, this file or directory is ignored.
+  absl::Status AddFiles(const std::string& base_dir, bool recursive,
+                        PathFilter* path_filter);
+
+  // Returns all found files and directories.
+  void ReleaseFiles(std::vector<FileInfo>* files, std::vector<DirInfo>* dirs);
+
+ private:
+  std::vector<FileInfo> files_;
+  std::vector<DirInfo> dirs_;
+};
+
+}  // namespace cdc_ft
+
+#endif  // CDC_RSYNC_SERVER_FILE_FINDER_H_