Commit 42c42914 authored by Ashwin Bharambe's avatar Ashwin Bharambe Committed by Facebook Github Bot

Outline `Optional::require_value()`

Summary:
We would like to use `folly/Optional` in settings where exceptions
are disabled. An example is ObjC++ codebases where supporting exceptions
doesn't quite help (since objc_msgSend() can throw) and yet we need to pay the
additional binary size cost for the unwind tables.

This patch makes a small change to outline the "assert" utility included
inside Optional.h

Reviewed By: yfeldblum, mzlee

Differential Revision: D5030172

fbshipit-source-id: 7def3c6eda22c41c8cab2037444978e0a4c50abf
parent c8aadaad
......@@ -525,6 +525,7 @@ libfolly_la_SOURCES = \
SharedMutex.cpp \
Shell.cpp \
MicroLock.cpp \
Optional.cpp \
Singleton.cpp \
SocketAddress.cpp \
SpookyHashV1.cpp \
......
/*
* Copyright 2017 Facebook, Inc.
*
* 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.
*/
#include <folly/Optional.h>
namespace folly {
namespace detail {
void throw_optional_empty_exception() {
throw OptionalEmptyException();
}
} // namespace detail
} // namespace folly
......@@ -64,7 +64,14 @@
namespace folly {
namespace detail { struct NoneHelper {}; }
namespace detail {
struct NoneHelper {};
// Allow each translation unit to control its own -fexceptions setting.
// If exceptions are disabled, std::terminate() will be called instead of
// throwing OptionalEmptyException when the condition fails.
[[noreturn]] void throw_optional_empty_exception();
}
typedef int detail::NoneHelper::*None;
......@@ -252,7 +259,7 @@ class Optional {
private:
void require_value() const {
if (!storage_.hasValue) {
throw OptionalEmptyException();
detail::throw_optional_empty_exception();
}
}
......
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