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/path_filter.cc

@@ -0,0 +1,80 @@
+// 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/path_filter.h"
+
+namespace cdc_ft {
+namespace internal {
+
+bool IsMatch(const char* pattern, const char* path, size_t path_len) {
+  for (/*empty*/; *pattern != '\0'; ++pattern) {
+    switch (*pattern) {
+      case '?':
+        if (*path == '\0') {
+          return false;
+        }
+        ++path;
+        break;
+
+      case '*': {
+        if (pattern[1] == '\0') {
+          return true;
+        }
+        for (size_t n = 0; n < path_len; n++) {
+          if (IsMatch(pattern + 1, path + n, path_len - n)) {
+            return true;
+          }
+        }
+        return false;
+      }
+
+      default:
+        if (*path != *pattern) {
+          return false;
+        }
+        ++path;
+    }
+  }
+  return *path == '\0';
+}
+
+bool IsMatch(const std::string& pattern, const std::string& path) {
+  return IsMatch(pattern.c_str(), path.c_str(), path.size());
+}
+
+}  // namespace internal
+
+PathFilter::PathFilter() = default;
+
+PathFilter::~PathFilter() = default;
+
+bool PathFilter::IsEmpty() const { return rules_.empty(); }
+
+void PathFilter::AddRule(Rule::Type type, std::string pattern) {
+  rules_.emplace_back(type, std::move(pattern));
+}
+
+bool PathFilter::IsMatch(const std::string& path) const {
+  for (const Rule& rule : rules_) {
+    if (internal::IsMatch(rule.pattern.c_str(), path.c_str(), path.size())) {
+      return rule.type == Rule::Type::kInclude;
+    }
+  }
+  return true;
+}
+
+PathFilter::Rule::Rule(Type type, std::string pattern)
+    : type(type), pattern(std::move(pattern)) {}
+
+}  // namespace cdc_ft