[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/Status.h b/staticlibs/netd/libnetdutils/include/netdutils/Status.h
new file mode 100644
index 0000000..bc347d5
--- /dev/null
+++ b/staticlibs/netd/libnetdutils/include/netdutils/Status.h
@@ -0,0 +1,136 @@
+/*
+ * 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_STATUS_H
+#define NETUTILS_STATUS_H
+
+#include <cassert>
+#include <limits>
+#include <ostream>
+
+#include <android-base/result.h>
+
+namespace android {
+namespace netdutils {
+
+// Simple status implementation suitable for use on the stack in low
+// or moderate performance code. This can definitely be improved but
+// for now short string optimization is expected to keep the common
+// success case fast.
+//
+// Status is implicitly movable via the default noexcept move constructor
+// and noexcept move-assignment operator.
+class [[nodiscard]] Status {
+ public:
+ Status() = default;
+ explicit Status(int code) : mCode(code) {}
+
+ // Constructs an error Status, |code| must be non-zero.
+ Status(int code, std::string msg) : mCode(code), mMsg(std::move(msg)) { assert(!ok()); }
+
+ Status(android::base::Result<void> result)
+ : mCode(result.ok() ? 0 : result.error().code()),
+ mMsg(result.ok() ? "" : result.error().message()) {}
+
+ int code() const { return mCode; }
+
+ bool ok() const { return code() == 0; }
+
+ const std::string& msg() const { return mMsg; }
+
+ // Explicitly ignores the Status without triggering [[nodiscard]] errors.
+ void ignoreError() const {}
+
+ bool operator==(const Status& other) const { return code() == other.code(); }
+ bool operator!=(const Status& other) const { return !(*this == other); }
+
+ private:
+ int mCode = 0;
+ std::string mMsg;
+};
+
+namespace status {
+
+const Status ok{0};
+// EOF is not part of errno space, we'll place it far above the
+// highest existing value.
+const Status eof{0x10001, "end of file"};
+const Status undefined{std::numeric_limits<int>::max(), "undefined"};
+
+} // namespace status
+
+// Return true if status is "OK". This is sometimes preferable to
+// status.ok() when we want to check the state of Status-like objects
+// that implicitly cast to Status.
+inline bool isOk(const Status& status) {
+ return status.ok();
+}
+
+// For use only in tests. Used for both Status and Status-like objects. See also isOk().
+#define EXPECT_OK(status) EXPECT_TRUE(isOk(status))
+#define ASSERT_OK(status) ASSERT_TRUE(isOk(status))
+
+// Documents that status is expected to be ok. This function may log
+// (or assert when running in debug mode) if status has an unexpected value.
+inline void expectOk(const Status& /*status*/) {
+ // TODO: put something here, for now this function serves solely as documentation.
+}
+
+// Convert POSIX errno to a Status object.
+// If Status is extended to have more features, this mapping may
+// become more complex.
+Status statusFromErrno(int err, const std::string& msg);
+
+// Helper that checks Status-like object (notably StatusOr) against a
+// value in the errno space.
+bool equalToErrno(const Status& status, int err);
+
+// Helper that converts Status-like object (notably StatusOr) to a
+// message.
+std::string toString(const Status& status);
+
+std::ostream& operator<<(std::ostream& os, const Status& s);
+
+// Evaluate 'stmt' to a Status object and if it results in an error, return that
+// error. Use 'tmp' as a variable name to avoid shadowing any variables named
+// tmp.
+#define RETURN_IF_NOT_OK_IMPL(tmp, stmt) \
+ do { \
+ ::android::netdutils::Status tmp = (stmt); \
+ if (!isOk(tmp)) { \
+ return tmp; \
+ } \
+ } while (false)
+
+// Create a unique variable name to avoid shadowing local variables.
+#define RETURN_IF_NOT_OK_CONCAT(line, stmt) RETURN_IF_NOT_OK_IMPL(__CONCAT(_status_, line), stmt)
+
+// Macro to allow exception-like handling of error return values.
+//
+// If the evaluation of stmt results in an error, return that error
+// from current function.
+//
+// Example usage:
+// Status bar() { ... }
+//
+// RETURN_IF_NOT_OK(status);
+// RETURN_IF_NOT_OK(bar());
+#define RETURN_IF_NOT_OK(stmt) RETURN_IF_NOT_OK_CONCAT(__LINE__, stmt)
+
+} // namespace netdutils
+} // namespace android
+
+#endif /* NETUTILS_STATUS_H */