gecko-dev/mfbt/Try.h

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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim: set ts=8 sts=2 et sw=2 tw=80:
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef mozilla_Try_h
#define mozilla_Try_h
#include "mozilla/Result.h"
/**
* MOZ_TRY(expr) is the C++ equivalent of Rust's `try!(expr);`. First, it
* evaluates expr, which must produce a Result value. On success, it
* discards the result altogether. On error, it immediately returns an error
* Result from the enclosing function.
*/
#define MOZ_TRY(expr) \
do { \
auto mozTryTempResult_ = ::mozilla::ToResult(expr); \
if (MOZ_UNLIKELY(mozTryTempResult_.isErr())) { \
return mozTryTempResult_.propagateErr(); \
} \
} while (0)
/**
* MOZ_TRY_VAR(target, expr) is the C++ equivalent of Rust's `target =
* try!(expr);`. First, it evaluates expr, which must produce a Result value. On
* success, the result's success value is assigned to target. On error,
* immediately returns the error result. |target| must be an lvalue.
*/
#define MOZ_TRY_VAR(target, expr) \
do { \
auto mozTryVarTempResult_ = (expr); \
if (MOZ_UNLIKELY(mozTryVarTempResult_.isErr())) { \
return mozTryVarTempResult_.propagateErr(); \
} \
(target) = mozTryVarTempResult_.unwrap(); \
} while (0)
#endif // mozilla_Try_h