1 /* 2 * Copyright 2019 Google LLC. 3 * Licensed under the Apache License, Version 2.0 (the "License"); 4 * you may not use this file except in compliance with the License. 5 * You may obtain a copy of the License at 6 * 7 * https://www.apache.org/licenses/LICENSE-2.0 8 * 9 * Unless required by applicable law or agreed to in writing, software 10 * distributed under the License is distributed on an "AS IS" BASIS, 11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 * See the License for the specific language governing permissions and 13 * limitations under the License. 14 */ 15 16 #ifndef PRIVATE_JOIN_AND_COMPUTE_UTIL_STATUS_MACROS_H_ 17 #define PRIVATE_JOIN_AND_COMPUTE_UTIL_STATUS_MACROS_H_ 18 19 #include "absl/base/port.h" 20 #include "absl/status/status.h" 21 #include "absl/status/statusor.h" 22 23 // Helper macro that checks if the right hand side (rexpression) evaluates to a 24 // StatusOr with Status OK, and if so assigns the value to the value on the left 25 // hand side (lhs), otherwise returns the error status. Example: 26 // ASSIGN_OR_RETURN(lhs, rexpression); 27 #ifndef ASSIGN_OR_RETURN 28 #define ASSIGN_OR_RETURN(lhs, rexpr) \ 29 PRIVATE_JOIN_AND_COMPUTE_ASSIGN_OR_RETURN_IMPL_( \ 30 PRIVATE_JOIN_AND_COMPUTE_STATUS_MACROS_IMPL_CONCAT_(status_or_value, \ 31 __LINE__), \ 32 lhs, rexpr) 33 34 // Internal helper. 35 #define PRIVATE_JOIN_AND_COMPUTE_ASSIGN_OR_RETURN_IMPL_(statusor, lhs, rexpr) \ 36 auto statusor = (rexpr); \ 37 if (ABSL_PREDICT_FALSE(!statusor.ok())) { \ 38 return std::move(statusor).status(); \ 39 } \ 40 lhs = *std::move(statusor) 41 #endif // ASSIGN_OR_RETURN 42 43 // Helper macro that checks if the given expression evaluates to a 44 // Status with Status OK. If not, returns the error status. Example: 45 // RETURN_IF_ERROR(expression); 46 #ifndef RETURN_IF_ERROR 47 #define RETURN_IF_ERROR(expr) \ 48 PRIVATE_JOIN_AND_COMPUTE_RETURN_IF_ERROR_IMPL_( \ 49 PRIVATE_JOIN_AND_COMPUTE_STATUS_MACROS_IMPL_CONCAT_(status_value, \ 50 __LINE__), \ 51 expr) 52 53 // Internal helper. 54 #define PRIVATE_JOIN_AND_COMPUTE_RETURN_IF_ERROR_IMPL_(status, expr) \ 55 auto status = (expr); \ 56 if (ABSL_PREDICT_FALSE(!status.ok())) { \ 57 return status; \ 58 } 59 #endif // RETURN_IF_ERROR 60 61 // Internal helper for concatenating macro values. 62 #define PRIVATE_JOIN_AND_COMPUTE_STATUS_MACROS_IMPL_CONCAT_INNER_(x, y) x##y 63 #define PRIVATE_JOIN_AND_COMPUTE_STATUS_MACROS_IMPL_CONCAT_(x, y) \ 64 PRIVATE_JOIN_AND_COMPUTE_STATUS_MACROS_IMPL_CONCAT_INNER_(x, y) 65 66 #endif // PRIVATE_JOIN_AND_COMPUTE_UTIL_STATUS_MACROS_H_ 67