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/*
* Copyright (C) 2018 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 LIBTEXTCLASSIFIER_UTILS_BASE_STATUS_MACROS_H_
#define LIBTEXTCLASSIFIER_UTILS_BASE_STATUS_MACROS_H_
#include <utility>
#include "utils/base/status.h"
#include "utils/base/statusor.h"
namespace libtextclassifier3 {
// An adapter to enable TC3_RETURN_IF_ERROR to be used with either Status or
// StatusOr.
class StatusAdapter {
public:
explicit StatusAdapter(const Status& s) : s_(s) {}
explicit StatusAdapter(Status&& s) : s_(std::move(s)) {}
template <typename T>
explicit StatusAdapter(const StatusOr<T>& s) : s_(s.status()) {}
template <typename T>
explicit StatusAdapter(StatusOr<T>&& s) : s_(std::move(s).status()) {}
bool ok() const { return s_.ok(); }
explicit operator bool() const { return ok(); }
const Status& status() const& { return s_; }
Status status() && { return std::move(s_); }
private:
Status s_;
};
} // namespace libtextclassifier3
// Evaluates an expression that produces a `libtextclassifier3::Status`. If the
// status is not ok, returns it from the current function.
//
// For example:
// libtextclassifier3::Status MultiStepFunction() {
// TC3_RETURN_IF_ERROR(Function(args...));
// TC3_RETURN_IF_ERROR(foo.Method(args...));
// return libtextclassifier3::Status();
// }
#define TC3_RETURN_IF_ERROR(expr) \
TC3_RETURN_IF_ERROR_INTERNAL(expr, std::move(adapter).status())
#define TC3_RETURN_NULL_IF_ERROR(expr) \
TC3_RETURN_IF_ERROR_INTERNAL(expr, nullptr)
#define TC3_RETURN_FALSE_IF_ERROR(expr) \
TC3_RETURN_IF_ERROR_INTERNAL(expr, false)
#define TC3_RETURN_IF_ERROR_INTERNAL(expr, return_value) \
TC3_STATUS_MACROS_IMPL_ELSE_BLOCKER_ \
if (::libtextclassifier3::StatusAdapter adapter{expr}) { \
} else /* NOLINT */ \
return return_value
// The GNU compiler emits a warning for code like:
//
// if (foo)
// if (bar) { } else baz;
//
// because it thinks you might want the else to bind to the first if. This
// leads to problems with code like:
//
// if (do_expr) TC3_RETURN_IF_ERROR(expr);
//
// The "switch (0) case 0:" idiom is used to suppress this.
#define TC3_STATUS_MACROS_IMPL_ELSE_BLOCKER_ \
switch (0) \
case 0: \
default: // NOLINT
#endif // LIBTEXTCLASSIFIER_UTILS_BASE_STATUS_MACROS_H_