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.

manifest/fake_manifest_builder.h

@@ -0,0 +1,73 @@
+/*
+ * 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 MANIFEST_FAKE_MANIFEST_BUILDER_H_
+#define MANIFEST_FAKE_MANIFEST_BUILDER_H_
+
+#include "manifest/manifest_proto_defs.h"
+
+namespace cdc_ft {
+
+class MemDataStore;
+
+// In-memory manifest builder. Useful for testing.
+class FakeManifestBuilder {
+ public:
+  // Permissions assigned to the root directory.
+  static constexpr uint32_t kRootDirPerms = 0755u;
+
+  explicit FakeManifestBuilder(MemDataStore* store);
+  ~FakeManifestBuilder();
+
+  // Adds a new file of given the |name| to the directory |dir_asset| and sets
+  // the modified time to |mtime_sec| and permissions to |permissions|. Also
+  // generates data chunks from |data| using fastcdc (hardcoded chunk sizes).
+  // Use builder.AddFile(builder.Root(), ...) to add a file to the root
+  // directory.
+  void AddFile(AssetProto* dir_asset, const char* name, int64_t mtime_sec,
+               uint32_t permissions, const std::vector<char>& data);
+
+  // Adds a new directory of the given |name| to the directory |dir_asset| and
+  // sets the modified time to |mtime_sec| and permissions to |permissions|.
+  // Returns a pointer to the new directory that can be used to further add
+  // files or subdirectories.
+  // Use builder.AddDirectory(builder.Root(), ...) to add a directory to the
+  // root directory.
+  AssetProto* AddDirectory(AssetProto* dir_asset, const char* name,
+                           int64_t mtime_sec, uint32_t permissions);
+
+  // Builds a fake directory structure with files and subdirectories suitable
+  // for prototyping/testing.
+  ContentIdProto BuildTestData();
+
+  // Returns the built manifest.
+  const ManifestProto* Manifest() const;
+
+  // Shortcut to &Manifest()->root_dir().
+  AssetProto* Root();
+
+  // Updates the file |name| with new |permissions|, |mtime_sec|, and |data|.
+  void ModifyFile(AssetProto* dir_asset, const char* name, int64_t mtime_sec,
+                  uint32_t permissions, const std::vector<char>& data);
+
+ private:
+  MemDataStore* const store_;
+  ManifestProto manifest_;
+};
+
+}  // namespace cdc_ft
+
+#endif  // MANIFEST_FAKE_MANIFEST_BUILDER_H_