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contrib/libcxxabi/src/include/refstring.h
- This file was added.
| Property | Old Value | New Value |
|---|---|---|
| svn:eol-style | null | native \ No newline at end of property |
| svn:keywords | null | FreeBSD=%H \ No newline at end of property |
| svn:mime-type | null | text/plain \ No newline at end of property |
| //===------------------------ __refstring ---------------------------------===// | |||||
| // | |||||
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. | |||||
| // See https://llvm.org/LICENSE.txt for license information. | |||||
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception | |||||
| // | |||||
| //===----------------------------------------------------------------------===// | |||||
| // FIXME: This file is copied from libcxx/src/include/refstring.h. Instead of | |||||
| // duplicating the file in libc++abi we should require that the libc++ sources | |||||
| // are available when building libc++abi. | |||||
| #ifndef _LIBCPPABI_REFSTRING_H | |||||
| #define _LIBCPPABI_REFSTRING_H | |||||
| #include <__config> | |||||
| #include <stdexcept> | |||||
| #include <cstddef> | |||||
| #include <cstring> | |||||
| #ifdef __APPLE__ | |||||
| #include <dlfcn.h> | |||||
| #include <mach-o/dyld.h> | |||||
| #endif | |||||
| #include "atomic_support.h" | |||||
| _LIBCPP_BEGIN_NAMESPACE_STD | |||||
| namespace __refstring_imp { namespace { | |||||
| typedef int count_t; | |||||
| struct _Rep_base { | |||||
| std::size_t len; | |||||
| std::size_t cap; | |||||
| count_t count; | |||||
| }; | |||||
| inline _Rep_base* rep_from_data(const char *data_) noexcept { | |||||
| char *data = const_cast<char *>(data_); | |||||
| return reinterpret_cast<_Rep_base *>(data - sizeof(_Rep_base)); | |||||
| } | |||||
| inline char * data_from_rep(_Rep_base *rep) noexcept { | |||||
| char *data = reinterpret_cast<char *>(rep); | |||||
| return data + sizeof(*rep); | |||||
| } | |||||
| #if defined(__APPLE__) | |||||
| inline | |||||
| const char* compute_gcc_empty_string_storage() _NOEXCEPT | |||||
| { | |||||
| void* handle = dlopen("/usr/lib/libstdc++.6.dylib", RTLD_NOLOAD); | |||||
| if (handle == nullptr) | |||||
| return nullptr; | |||||
| void* sym = dlsym(handle, "_ZNSs4_Rep20_S_empty_rep_storageE"); | |||||
| if (sym == nullptr) | |||||
| return nullptr; | |||||
| return data_from_rep(reinterpret_cast<_Rep_base *>(sym)); | |||||
| } | |||||
| inline | |||||
| const char* | |||||
| get_gcc_empty_string_storage() _NOEXCEPT | |||||
| { | |||||
| static const char* p = compute_gcc_empty_string_storage(); | |||||
| return p; | |||||
| } | |||||
| #endif | |||||
| }} // namespace __refstring_imp | |||||
| using namespace __refstring_imp; | |||||
| inline | |||||
| __libcpp_refstring::__libcpp_refstring(const char* msg) { | |||||
| std::size_t len = strlen(msg); | |||||
| _Rep_base* rep = static_cast<_Rep_base *>(::operator new(sizeof(*rep) + len + 1)); | |||||
| rep->len = len; | |||||
| rep->cap = len; | |||||
| rep->count = 0; | |||||
| char *data = data_from_rep(rep); | |||||
| std::memcpy(data, msg, len + 1); | |||||
| __imp_ = data; | |||||
| } | |||||
| inline | |||||
| __libcpp_refstring::__libcpp_refstring(const __libcpp_refstring &s) _NOEXCEPT | |||||
| : __imp_(s.__imp_) | |||||
| { | |||||
| if (__uses_refcount()) | |||||
| __libcpp_atomic_add(&rep_from_data(__imp_)->count, 1); | |||||
| } | |||||
| inline | |||||
| __libcpp_refstring& __libcpp_refstring::operator=(__libcpp_refstring const& s) _NOEXCEPT { | |||||
| bool adjust_old_count = __uses_refcount(); | |||||
| struct _Rep_base *old_rep = rep_from_data(__imp_); | |||||
| __imp_ = s.__imp_; | |||||
| if (__uses_refcount()) | |||||
| __libcpp_atomic_add(&rep_from_data(__imp_)->count, 1); | |||||
| if (adjust_old_count) | |||||
| { | |||||
| if (__libcpp_atomic_add(&old_rep->count, count_t(-1)) < 0) | |||||
| { | |||||
| ::operator delete(old_rep); | |||||
| } | |||||
| } | |||||
| return *this; | |||||
| } | |||||
| inline | |||||
| __libcpp_refstring::~__libcpp_refstring() { | |||||
| if (__uses_refcount()) { | |||||
| _Rep_base* rep = rep_from_data(__imp_); | |||||
| if (__libcpp_atomic_add(&rep->count, count_t(-1)) < 0) { | |||||
| ::operator delete(rep); | |||||
| } | |||||
| } | |||||
| } | |||||
| inline | |||||
| bool __libcpp_refstring::__uses_refcount() const { | |||||
| #ifdef __APPLE__ | |||||
| return __imp_ != get_gcc_empty_string_storage(); | |||||
| #else | |||||
| return true; | |||||
| #endif | |||||
| } | |||||
| _LIBCPP_END_NAMESPACE_STD | |||||
| #endif //_LIBCPPABI_REFSTRING_H | |||||