[NETD-BPF#1] Move libnetdutils to frameworks/libs/net/...
libnetdutils is referenced by netd.c and TrafficController.cpp, which
are going to be mainlined. Therefore, move libnetdutils to a common
place where both mainline module and platform code (Netd) can refer to.
Bug: 202086915
Test: build; flash; cd system/netd; atest
Ignore-AOSP-First: the netd change(same topic) would not automerge from
aosp.
No-Typo-Check: Clean code move with no other changes.
BYPASS_INCLUSIVE_LANGUAGE_REASON=Clean code move with no other changes.
Change-Id: I645bfe35f6543149c9a9f894cd4158d27a481abe
diff --git a/staticlibs/netd/libnetdutils/include/netdutils/Fd.h b/staticlibs/netd/libnetdutils/include/netdutils/Fd.h
new file mode 100644
index 0000000..7db4087
--- /dev/null
+++ b/staticlibs/netd/libnetdutils/include/netdutils/Fd.h
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * 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.
+ */
+
+#ifndef NETUTILS_FD_H
+#define NETUTILS_FD_H
+
+#include <ostream>
+
+#include "netdutils/Status.h"
+
+namespace android {
+namespace netdutils {
+
+// Strongly typed wrapper for file descriptors with value semantics.
+// This class should typically hold unowned file descriptors.
+class Fd {
+ public:
+ constexpr Fd() = default;
+
+ constexpr Fd(int fd) : mFd(fd) {}
+
+ int get() const { return mFd; }
+
+ bool operator==(const Fd& other) const { return get() == other.get(); }
+ bool operator!=(const Fd& other) const { return get() != other.get(); }
+
+ private:
+ int mFd = -1;
+};
+
+// Return true if fd appears valid (non-negative)
+inline bool isWellFormed(const Fd fd) {
+ return fd.get() >= 0;
+}
+
+std::ostream& operator<<(std::ostream& os, const Fd& fd);
+
+} // namespace netdutils
+} // namespace android
+
+#endif /* NETUTILS_FD_H */