| /* |
| * Copyright (C) 2017 The Android Open Source Project |
| * |
| * 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. |
| */ |
| |
| #ifndef LIBTEXTCLASSIFIER_UTIL_BASE_MACROS_H_ |
| #define LIBTEXTCLASSIFIER_UTIL_BASE_MACROS_H_ |
| |
| #include "util/base/config.h" |
| |
| namespace libtextclassifier2 { |
| |
| #if LANG_CXX11 |
| #define TC_DISALLOW_COPY_AND_ASSIGN(TypeName) \ |
| TypeName(const TypeName &) = delete; \ |
| TypeName &operator=(const TypeName &) = delete |
| #else // C++98 case follows |
| |
| // Note that these C++98 implementations cannot completely disallow copying, |
| // as members and friends can still accidentally make elided copies without |
| // triggering a linker error. |
| #define TC_DISALLOW_COPY_AND_ASSIGN(TypeName) \ |
| TypeName(const TypeName &); \ |
| TypeName &operator=(const TypeName &) |
| #endif // LANG_CXX11 |
| |
| // The TC_FALLTHROUGH_INTENDED macro can be used to annotate implicit |
| // fall-through between switch labels: |
| // |
| // switch (x) { |
| // case 40: |
| // case 41: |
| // if (truth_is_out_there) { |
| // ++x; |
| // TC_FALLTHROUGH_INTENDED; // Use instead of/along with annotations in |
| // // comments. |
| // } else { |
| // return x; |
| // } |
| // case 42: |
| // ... |
| // |
| // As shown in the example above, the TC_FALLTHROUGH_INTENDED macro should be |
| // followed by a semicolon. It is designed to mimic control-flow statements |
| // like 'break;', so it can be placed in most places where 'break;' can, but |
| // only if there are no statements on the execution path between it and the |
| // next switch label. |
| // |
| // When compiled with clang in C++11 mode, the TC_FALLTHROUGH_INTENDED macro is |
| // expanded to [[clang::fallthrough]] attribute, which is analysed when |
| // performing switch labels fall-through diagnostic ('-Wimplicit-fallthrough'). |
| // See clang documentation on language extensions for details: |
| // http://clang.llvm.org/docs/AttributeReference.html#fallthrough-clang-fallthrough |
| // |
| // When used with unsupported compilers, the TC_FALLTHROUGH_INTENDED macro has |
| // no effect on diagnostics. |
| // |
| // In either case this macro has no effect on runtime behavior and performance |
| // of code. |
| #if defined(__clang__) && defined(LANG_CXX11) && defined(__has_warning) |
| #if __has_feature(cxx_attributes) && __has_warning("-Wimplicit-fallthrough") |
| #define TC_FALLTHROUGH_INTENDED [[clang::fallthrough]] // NOLINT |
| #endif |
| #endif |
| |
| #ifndef TC_FALLTHROUGH_INTENDED |
| #define TC_FALLTHROUGH_INTENDED do { } while (0) |
| #endif |
| |
| } // namespace libtextclassifier2 |
| |
| #endif // LIBTEXTCLASSIFIER_UTIL_BASE_MACROS_H_ |