| // Copyright 2021 The Chromium OS Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef MISSIVE_UTIL_STATUS_MACROS_H_ |
| #define MISSIVE_UTIL_STATUS_MACROS_H_ |
| |
| #include <utility> |
| |
| #include "missive/util/status.h" |
| #include "missive/util/statusor.h" |
| |
| namespace reporting { |
| |
| // Run a command that returns a Status. If the called code returns an |
| // error status, return that status up out of this method too. |
| // |
| // Example: |
| // RETURN_IF_ERROR(DoThings(4)); |
| #define RETURN_IF_ERROR(expr) \ |
| do { \ |
| /* Using _status below to avoid capture problems if expr is "status". */ \ |
| const ::reporting::Status _status = (expr); \ |
| if (__builtin_expect(!_status.ok(), 0)) \ |
| return _status; \ |
| } while (0) |
| |
| // Internal helper for concatenating macro values. |
| #define STATUS_MACROS_CONCAT_NAME_INNER(x, y) x##y |
| #define STATUS_MACROS_CONCAT_NAME(x, y) STATUS_MACROS_CONCAT_NAME_INNER(x, y) |
| |
| #define ASSIGN_OR_RETURN_IMPL(result, lhs, rexpr) \ |
| auto result = rexpr; \ |
| if (__builtin_expect(!result.ok(), 0)) { \ |
| return result.status(); \ |
| } \ |
| lhs = std::move(result).ValueOrDie() |
| |
| // Executes an expression that returns a StatusOr, extracting its value |
| // into the variable defined by lhs (or returning on error). |
| // |
| // Example: Assigning to an existing value |
| // ValueType value; |
| // ASSIGN_OR_RETURN(value, MaybeGetValue(arg)); |
| // |
| // Example: Creating and assigning variable in one line. |
| // ASSIGN_OR_RETURN(ValueType value, MaybeGetValue(arg)); |
| // DoSomethingWithValueType(value); |
| // |
| // WARNING: ASSIGN_OR_RETURN expands into multiple statements; it cannot be used |
| // in a single statement (e.g. as the body of an if statement without {})! |
| #define ASSIGN_OR_RETURN(lhs, rexpr) \ |
| ASSIGN_OR_RETURN_IMPL( \ |
| STATUS_MACROS_CONCAT_NAME(_status_or_value, __COUNTER__), lhs, rexpr) |
| |
| #define ASSIGN_OR_ONCE_CALLBACK_AND_RETURN_IMPL(result, lhs, callback, rexpr) \ |
| const auto result = (rexpr); \ |
| if (__builtin_expect(!result.ok(), 0)) { \ |
| std::move(callback).Run(result.status()); \ |
| return; \ |
| } \ |
| lhs = result.ValueOrDie(); |
| |
| // Executes an expression that returns a StatusOr, extracting its value into the |
| // variabled defined by lhs (or calls callback with error and returns). |
| // |
| // Example: |
| // base::OnceCallback<void(Status)> callback = |
| // base::BindOnce([](Status status) {...}); |
| // ASSIGN_OR_ONCE_CALLBACK_AND_RETURN(ValueType value, |
| // callback, |
| // MaybeGetValue(arg)); |
| // |
| // WARNING: ASSIGN_OR_RETURN expands into multiple statements; it cannot be used |
| // in a single statement (e.g. as the body of an if statement without {})! |
| #define ASSIGN_OR_ONCE_CALLBACK_AND_RETURN(lhs, callback, rexpr) \ |
| ASSIGN_OR_ONCE_CALLBACK_AND_RETURN_IMPL( \ |
| STATUS_MACROS_CONCAT_NAME(_status_or_value, __COUNTER__), lhs, callback, \ |
| rexpr) |
| |
| } // namespace reporting |
| |
| #endif // MISSIVE_UTIL_STATUS_MACROS_H_ |