68 lines
2.3 KiB
C++
68 lines
2.3 KiB
C++
/*
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* Copyright (c) Facebook, Inc. and its affiliates.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#pragma once
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#include <exception>
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#if !defined(FOLLY_FORCE_EXCEPTION_COUNT_USE_STD) && defined(__GNUG__)
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#define FOLLY_EXCEPTION_COUNT_USE_CXA_GET_GLOBALS
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namespace __cxxabiv1 {
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// forward declaration (originally defined in unwind-cxx.h from from libstdc++)
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struct __cxa_eh_globals;
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// declared in cxxabi.h from libstdc++-v3
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#if !defined(__FreeBSD__)
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extern "C" __cxa_eh_globals* __cxa_get_globals() noexcept;
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#else
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// Signature mismatch with FreeBSD case
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extern "C" __cxa_eh_globals* __cxa_get_globals(void);
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#endif
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} // namespace __cxxabiv1
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#elif defined(FOLLY_FORCE_EXCEPTION_COUNT_USE_STD) || defined(_MSC_VER)
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#define FOLLY_EXCEPTION_COUNT_USE_STD
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#else
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// Raise an error when trying to use this on unsupported platforms.
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#error "Unsupported platform, don't include this header."
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#endif
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namespace folly {
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/**
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* Returns the number of uncaught exceptions.
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*
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* This function is based on Evgeny Panasyuk's implementation from here:
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* http://fburl.com/15190026
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*/
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inline int uncaught_exceptions() noexcept {
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#if defined(FOLLY_EXCEPTION_COUNT_USE_CXA_GET_GLOBALS)
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// __cxa_get_globals returns a __cxa_eh_globals* (defined in unwind-cxx.h).
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// The offset below returns __cxa_eh_globals::uncaughtExceptions.
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return *(reinterpret_cast<unsigned int*>(
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static_cast<char*>(static_cast<void*>(__cxxabiv1::__cxa_get_globals())) +
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sizeof(void*)));
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#elif defined(FOLLY_EXCEPTION_COUNT_USE_GETPTD)
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// _getptd() returns a _tiddata* (defined in mtdll.h).
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// The offset below returns _tiddata::_ProcessingThrow.
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return *(reinterpret_cast<int*>(
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static_cast<char*>(static_cast<void*>(_getptd())) + sizeof(void*) * 28 +
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0x4 * 8));
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#elif defined(FOLLY_EXCEPTION_COUNT_USE_STD)
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return std::uncaught_exceptions();
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#endif
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}
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} // namespace folly
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