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/manifest_printer.cc

@@ -0,0 +1,59 @@
+// 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/manifest_printer.h"
+
+#include "manifest/content_id.h"
+#include "manifest/manifest_proto_defs.h"
+
+namespace cdc_ft {
+
+// A special text proto printer that prints all ContentId protos using a
+// hexadecimal representation instead of octal-escaped string values.
+class ContentIdPrinter : public google::protobuf::TextFormat::MessagePrinter {
+ public:
+  ContentIdPrinter() = default;
+  virtual ~ContentIdPrinter() = default;
+  void Print(const google::protobuf::Message& message, bool single_line_mode,
+             google::protobuf::TextFormat::BaseTextGenerator* generator)
+      const override {
+    const ContentIdProto* content_id =
+        dynamic_cast<const ContentIdProto*>(&message);
+    if (content_id) {
+      generator->PrintLiteral("blake3_sum_160: \"");
+      generator->PrintString(ContentId::ToHexString(*content_id));
+      generator->PrintLiteral("\"");
+    } else {
+      // Technically, we should just call the inherited Print() function, but
+      // this results in a linker error for unknown reasons. But since we are
+      // never supposed to be called for any other message type, let's not
+      // bother.
+      generator->PrintLiteral("(given message is no ContentId proto)");
+    }
+    if (!single_line_mode) generator->PrintLiteral("\n");
+  }
+};
+
+ManifestPrinter::ManifestPrinter() {
+  ContentIdPrinter* printer = new ContentIdPrinter;
+  // If registration of a printer is successful, the callee takes ownership of
+  // the object.
+  if (!RegisterMessagePrinter(ContentIdProto::default_instance().descriptor(),
+                              printer)) {
+    // Registration unsuccessful, delete the object.
+    delete printer;
+  }
+}
+
+}  // namespace cdc_ft