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.

common/gamelet_component.cc

@@ -0,0 +1,92 @@
+// 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 "common/gamelet_component.h"
+
+#include <cinttypes>
+
+#include "absl/strings/str_format.h"
+#include "absl/strings/str_split.h"
+#include "common/path.h"
+#include "common/status.h"
+
+namespace cdc_ft {
+
+GameletComponent::GameletComponent(std::string filename, uint64_t size,
+                                   time_t modified_time)
+    : filename(filename), size(size), modified_time(modified_time) {}
+
+GameletComponent::~GameletComponent() = default;
+
+bool GameletComponent::operator==(const GameletComponent& other) const {
+  return filename == other.filename && size == other.size &&
+         modified_time == other.modified_time;
+}
+
+bool GameletComponent::operator!=(const GameletComponent& other) const {
+  return !(*this == other);
+}
+
+// static
+absl::Status GameletComponent::Get(
+    const std::vector<std::string> component_paths,
+    std::vector<GameletComponent>* components) {
+  components->clear();
+
+  for (const std::string& path : component_paths) {
+    path::Stats stats;
+    absl::Status status = path::GetStats(path, &stats);
+    if (!status.ok())
+      return WrapStatus(status, "GetStats() failed for '%s'", path);
+    components->emplace_back(path::BaseName(path), stats.size,
+                             stats.modified_time);
+  }
+
+  return absl::OkStatus();
+}
+
+// static
+std::string GameletComponent::ToCommandLineArgs(
+    const std::vector<GameletComponent>& components) {
+  std::string args;
+  for (const GameletComponent& comp : components) {
+    args +=
+        absl::StrFormat("%s%s %u %d", args.empty() ? "" : " ",
+                        comp.filename.c_str(), comp.size, comp.modified_time);
+  }
+  return args;
+}
+
+// static
+std::vector<GameletComponent> GameletComponent::FromCommandLineArgs(
+    int argc, const char** argv) {
+  std::vector<GameletComponent> components;
+  for (int n = 0; n + 2 < argc; n += 3) {
+    components.emplace_back(argv[n], std::stol(argv[n + 1]),
+                            std::stol(argv[n + 2]));
+  }
+  return components;
+}
+
+// static
+std::vector<GameletComponent> GameletComponent::FromCommandLineArgs(
+    const std::string& components_arg) {
+  std::vector<std::string> args_vec = absl::StrSplit(components_arg, ' ');
+  int argc = static_cast<int>(args_vec.size());
+  std::vector<const char*> argv;
+  for (const std::string& arg : args_vec) argv.push_back(arg.c_str());
+  return FromCommandLineArgs(argc, argv.data());
+}
+
+}  // namespace cdc_ft