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/zstd_stream_test.cc

@@ -0,0 +1,72 @@
+// 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 "cdc_rsync/zstd_stream.h"
+
+#include "cdc_rsync/base/fake_socket.h"
+#include "cdc_rsync_server/unzstd_stream.h"
+#include "common/status_test_macros.h"
+#include "gtest/gtest.h"
+
+namespace cdc_ft {
+namespace {
+
+class ZstdStreamTest : public ::testing::Test {
+ protected:
+  FakeSocket socket_;
+  ZstdStream cstream_{&socket_, /*level=*/6, /*num_threads=*/8};
+  UnzstdStream dstream_{&socket_};
+};
+
+TEST_F(ZstdStreamTest, Small) {
+  const std::string want = "Lorem ipsum gibberisulum foobarberis";
+  EXPECT_OK(cstream_.Write(want.data(), want.size()));
+  EXPECT_OK(cstream_.Flush());
+
+  Buffer buff(1024);
+  size_t bytes_read;
+  bool eof = false;
+  EXPECT_OK(dstream_.Read(buff.data(), buff.size(), &bytes_read, &eof));
+  EXPECT_TRUE(eof);
+  std::string got(buff.data(), bytes_read);
+  EXPECT_EQ(got, want);
+}
+
+TEST_F(ZstdStreamTest, Large) {
+  Buffer want(1024 * 1024 * 10 + 12345);
+  constexpr uint64_t prime = 919393;
+  for (size_t n = 0; n < want.size(); ++n) {
+    want.data()[n] = ((n * prime) % 26) + 'a';
+  }
+
+  constexpr int kChunkSize = 19 * 1024;
+  for (size_t pos = 0; pos < want.size(); pos += kChunkSize) {
+    size_t size = std::min<size_t>(kChunkSize, want.size() - pos);
+    EXPECT_OK(cstream_.Write(want.data() + pos, size));
+  }
+  EXPECT_OK(cstream_.Flush());
+
+  bool eof = false;
+  Buffer buff(128 * 1024);
+  Buffer got;
+  while (!eof) {
+    size_t bytes_read;
+    EXPECT_OK(dstream_.Read(buff.data(), buff.size(), &bytes_read, &eof));
+    got.append(buff.data(), bytes_read);
+  }
+  EXPECT_EQ(want, got);
+}
+
+}  // namespace
+}  // namespace cdc_ft