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/buffer_test.cc

@@ -0,0 +1,167 @@
+// 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/buffer.h"
+
+#include <cstring>
+
+#include "gtest/gtest.h"
+
+namespace cdc_ft {
+namespace {
+
+TEST(BufferTest, ConstructDefault) {
+  Buffer b;
+  EXPECT_EQ(b.size(), 0);
+  EXPECT_EQ(b.data(), nullptr);
+}
+
+TEST(BufferTest, ConstructWithSize) {
+  Buffer b(32);
+  EXPECT_EQ(b.size(), 32);
+  EXPECT_EQ(b.capacity(), 32);
+  EXPECT_NE(b.data(), nullptr);
+  // This shouldn't crash.
+  memset(b.data(), 0, b.size());
+}
+
+TEST(BufferTest, ConstructWithInitializerList) {
+  Buffer b({'1', '2', '3', '4', '5', '6', '7', '8', '9'});
+  EXPECT_EQ(b.size(), 9);
+  EXPECT_EQ(b.capacity(), 9);
+  EXPECT_NE(b.data(), nullptr);
+  EXPECT_EQ(memcmp(b.data(), "123456789", 9), 0);
+}
+
+TEST(BufferTest, MoveConstructor) {
+  Buffer b({9});
+  Buffer b2(std::move(b));
+
+  EXPECT_EQ(b.size(), 0);
+  EXPECT_EQ(b.data(), nullptr);
+  EXPECT_EQ(b.capacity(), 0);
+
+  EXPECT_EQ(b2.size(), 1);
+  EXPECT_NE(b2.data(), nullptr);
+  EXPECT_EQ(*b2.data(), 9);
+}
+
+TEST(BufferTest, MoveOperator) {
+  Buffer b({9});
+  Buffer b2({12, 13});
+
+  b2 = std::move(b);
+
+  EXPECT_EQ(b.size(), 0);
+  EXPECT_EQ(b.data(), nullptr);
+  EXPECT_EQ(b.capacity(), 0);
+
+  EXPECT_EQ(b2.size(), 1);
+  EXPECT_NE(b2.data(), nullptr);
+  EXPECT_EQ(*b2.data(), 9);
+}
+
+TEST(BufferTest, EqualsOperator) {
+  Buffer b({1});
+  Buffer b2({1});
+  Buffer b3({2});
+
+  EXPECT_TRUE(b == b2);
+  EXPECT_FALSE(b == b3);
+
+  EXPECT_FALSE(b != b2);
+  EXPECT_TRUE(b != b3);
+}
+
+TEST(BufferTest, SizeIncrease) {
+  Buffer b(8);
+  EXPECT_EQ(b.size(), 8);
+  EXPECT_EQ(b.capacity(), 8);
+  EXPECT_NE(b.data(), nullptr);
+  memcpy(b.data(), "01234567", 8);
+
+  // Should realloc the buffer, but keep the data.
+  b.resize(10);
+  EXPECT_EQ(b.size(), 10);
+  EXPECT_EQ(b.capacity(), 15);
+  EXPECT_NE(b.data(), nullptr);
+  EXPECT_EQ(memcmp(b.data(), "01234567", 8), 0);
+  memcpy(b.data(), "0123456789", 10);
+
+  // Should not realloc the buffer and keep data.
+  b.resize(12);
+  EXPECT_EQ(b.size(), 12);
+  EXPECT_EQ(b.capacity(), 15);
+  EXPECT_NE(b.data(), nullptr);
+  EXPECT_EQ(memcmp(b.data(), "0123456789", 10), 0);
+}
+
+TEST(BufferTest, SizeDecrease) {
+  Buffer b(8);
+  EXPECT_EQ(b.size(), 8);
+  EXPECT_EQ(b.capacity(), 8);
+  EXPECT_NE(b.data(), nullptr);
+  memcpy(b.data(), "01234567", 8);
+
+  // Should not realloc the buffer and keep data.
+  b.resize(2);
+  EXPECT_EQ(b.size(), 2);
+  EXPECT_EQ(b.capacity(), 8);
+  EXPECT_NE(b.data(), nullptr);
+  EXPECT_EQ(memcmp(b.data(), "01", 2), 0);
+}
+
+TEST(BufferTest, Reserve) {
+  Buffer b({1});
+  Buffer b2({1});
+  Buffer b3({2});
+
+  EXPECT_TRUE(b == b2);
+  EXPECT_FALSE(b == b3);
+
+  EXPECT_FALSE(b != b2);
+  EXPECT_TRUE(b != b3);
+}
+
+TEST(BufferTest, Empty) {
+  Buffer b;
+  EXPECT_TRUE(b.empty());
+  b = {};
+  EXPECT_TRUE(b.empty());
+  b = {1};
+  EXPECT_FALSE(b.empty());
+}
+
+TEST(BufferTest, Append) {
+  Buffer b;
+  b.append("9", 1);
+  EXPECT_EQ(b, Buffer({'9'}));
+  b.append("123", 3);
+  EXPECT_EQ(b, Buffer({'9', '1', '2', '3'}));
+}
+
+TEST(BufferTest, Clear) {
+  Buffer b(8);
+  EXPECT_EQ(b.size(), 8);
+  EXPECT_EQ(b.capacity(), 8);
+  EXPECT_NE(b.data(), nullptr);
+
+  b.clear();
+  EXPECT_EQ(b.size(), 0);
+  EXPECT_EQ(b.capacity(), 8);
+  EXPECT_NE(b.data(), nullptr);
+}
+
+}  // namespace
+}  // namespace cdc_ft