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/asset_builder.cc

@@ -0,0 +1,115 @@
+// 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.
+
+#include "manifest/asset_builder.h"
+
+#include "absl/strings/str_cat.h"
+#include "common/path.h"
+
+namespace cdc_ft {
+
+AssetBuilder::AssetBuilder() = default;
+
+AssetBuilder::AssetBuilder(AssetProto* proto, const std::string& rel_path)
+    : proto_(proto), rel_path_(path::ToUnix(rel_path)) {}
+
+AssetBuilder::~AssetBuilder() = default;
+
+std::string AssetBuilder::RelativeFilePath() const {
+  if (!proto_) return std::string();
+  return path::JoinUnix(rel_path_, proto_->name());
+}
+
+void AssetBuilder::AppendChunk(const ContentIdProto& content_id, size_t len) {
+  assert(proto_ != nullptr);
+  assert(proto_->type() == AssetProto::FILE);
+  // TODO: Handle indirect chunks.
+  assert(proto_->file_indirect_chunks_size() == 0);
+  ChunkRefProto* chunk_ref = proto_->add_file_chunks();
+  chunk_ref->set_offset(proto_->file_size());
+  chunk_ref->mutable_chunk_id()->CopyFrom(content_id);
+  proto_->set_file_size(proto_->file_size() + len);
+}
+
+void AssetBuilder::TruncateChunks() {
+  assert(proto_ != nullptr);
+  assert(proto_->type() == AssetProto::FILE);
+  proto_->mutable_file_chunks()->Clear();
+  proto_->mutable_file_indirect_chunks()->Clear();
+  proto_->set_file_size(0);
+}
+
+void AssetBuilder::SetChunks(const RepeatedChunkRefProto& chunks,
+                             uint64_t file_size) {
+  assert(proto_ != nullptr);
+  assert(proto_->type() == AssetProto::FILE);
+  proto_->mutable_file_chunks()->Clear();
+  proto_->mutable_file_chunks()->CopyFrom(chunks);
+  proto_->mutable_file_indirect_chunks()->Clear();
+  proto_->set_file_size(file_size);
+}
+
+void AssetBuilder::SwapChunks(RepeatedChunkRefProto* chunks,
+                              uint64_t file_size) {
+  assert(proto_ != nullptr);
+  assert(proto_->type() == AssetProto::FILE);
+  proto_->mutable_file_chunks()->Swap(chunks);
+  proto_->mutable_file_indirect_chunks()->Clear();
+  proto_->set_file_size(file_size);
+}
+
+void AssetBuilder::SetFileSize(uint64_t file_size) {
+  assert(proto_ != nullptr);
+  assert(proto_->type() == AssetProto::FILE);
+  proto_->set_file_size(file_size);
+}
+
+AssetBuilder AssetBuilder::AppendAsset(const std::string& name,
+                                       AssetProto::Type type) {
+  assert(proto_ != nullptr);
+  assert(proto_->type() == AssetProto::DIRECTORY);
+  AssetProto* child = proto_->add_dir_assets();
+  child->set_type(type);
+  child->set_name(name);
+  return AssetBuilder(child, RelativeFilePath());
+}
+
+bool AssetBuilder::InProgress() const {
+  if (!proto_) return false;
+  return proto_->in_progress();
+}
+
+void AssetBuilder::SetInProgress(bool in_progress) {
+  assert(proto_ != nullptr);
+  proto_->set_in_progress(in_progress);
+}
+
+void AssetBuilder::SetProto(AssetProto* proto, const std::string& rel_path) {
+  Clear();
+  proto_ = proto;
+  absl::StrAppend(&rel_path_, path::ToUnix(rel_path));
+}
+
+void AssetBuilder::Clear() {
+  proto_ = nullptr;
+  rel_path_.resize(0);
+}
+
+AssetBuilder& AssetBuilder::operator=(const AssetBuilder& other) {
+  proto_ = other.proto_;
+  rel_path_ = other.rel_path_;
+  return *this;
+}
+
+}  // namespace cdc_ft