scoped_clear_last_error.h (1672B)
1 // Copyright 2018 The Chromium Authors 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef BASE_SCOPED_CLEAR_LAST_ERROR_H_ 6 #define BASE_SCOPED_CLEAR_LAST_ERROR_H_ 7 8 #include <errno.h> 9 10 #include "base/base_export.h" 11 #include "build/build_config.h" 12 13 namespace base { 14 15 // ScopedClearLastError stores and resets the value of thread local error codes 16 // (errno, GetLastError()), and restores them in the destructor. This is useful 17 // to avoid side effects on these values in instrumentation functions that 18 // interact with the OS. 19 20 // Common implementation of ScopedClearLastError for all platforms. Use 21 // ScopedClearLastError instead. 22 class BASE_EXPORT ScopedClearLastErrorBase { 23 public: 24 ScopedClearLastErrorBase() : last_errno_(errno) { errno = 0; } 25 ScopedClearLastErrorBase(const ScopedClearLastErrorBase&) = delete; 26 ScopedClearLastErrorBase& operator=(const ScopedClearLastErrorBase&) = delete; 27 ~ScopedClearLastErrorBase() { errno = last_errno_; } 28 29 private: 30 const int last_errno_; 31 }; 32 33 #if BUILDFLAG(IS_WIN) 34 35 // Windows specific implementation of ScopedClearLastError. 36 class BASE_EXPORT ScopedClearLastError : public ScopedClearLastErrorBase { 37 public: 38 ScopedClearLastError(); 39 ScopedClearLastError(const ScopedClearLastError&) = delete; 40 ScopedClearLastError& operator=(const ScopedClearLastError&) = delete; 41 ~ScopedClearLastError(); 42 43 private: 44 const unsigned long last_system_error_; 45 }; 46 47 #elif BUILDFLAG(IS_POSIX) || BUILDFLAG(IS_FUCHSIA) 48 49 using ScopedClearLastError = ScopedClearLastErrorBase; 50 51 #endif // BUILDFLAG(IS_WIN) 52 53 } // namespace base 54 55 #endif // BASE_SCOPED_CLEAR_LAST_ERROR_H_