1 /* 2 * Copyright (C) 2017 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef NETUTILS_STATUS_H 18 #define NETUTILS_STATUS_H 19 20 #include "binder/Status.h" 21 #include <cassert> 22 #include <ostream> 23 24 namespace android { 25 namespace netdutils { 26 27 // Simple status implementation suitable for use on the stack in low 28 // or moderate performance code. This can definitely be improved but 29 // for now short string optimization is expected to keep the common 30 // success case fast. 31 class Status { 32 public: 33 Status() = default; 34 35 explicit Status(int code) : mCode(code) {} 36 37 Status(int code, const std::string& msg) : mCode(code), mMsg(msg) { assert(!ok()); } 38 39 int code() const { return mCode; } 40 41 bool ok() const { return code() == 0; } 42 43 const std::string& msg() const { return mMsg; } 44 45 bool operator==(const Status& other) const { return code() == other.code(); } 46 bool operator!=(const Status& other) const { return !(*this == other); } 47 48 private: 49 int mCode = 0; 50 std::string mMsg; 51 }; 52 53 namespace status { 54 55 const Status ok{0}; 56 // EOF is not part of errno space, we'll place it far above the 57 // highest existing value. 58 const Status eof{0x10001, "end of file"}; 59 const Status undefined{std::numeric_limits<int>::max(), "undefined"}; 60 61 } // namespace status 62 63 // Return true if status is "OK". This is sometimes preferable to 64 // status.ok() when we want to check the state of Status-like objects 65 // that implicitly cast to Status. 66 inline bool isOk(const Status& status) { 67 return status.ok(); 68 } 69 70 // Document that status is expected to be ok. This function may log 71 // (or assert when running in debug mode) if status has an unexpected 72 // value. 73 void expectOk(const Status& status); 74 75 // Convert POSIX errno to a Status object. 76 // If Status is extended to have more features, this mapping may 77 // become more complex. 78 Status statusFromErrno(int err, const std::string& msg); 79 80 // Helper that checks Status-like object (notably StatusOr) against a 81 // value in the errno space. 82 bool equalToErrno(const Status& status, int err); 83 84 // Converts netdutils Status into binder Status. 85 binder::Status asBinderStatus(const netdutils::Status& status); 86 87 // Helper that converts Status-like object (notably StatusOr) to a 88 // message. 89 std::string toString(const Status& status); 90 91 std::ostream& operator<<(std::ostream& os, const Status& s); 92 93 // Evaluate 'stmt' to a Status object and if it results in an error, return that 94 // error. Use 'tmp' as a variable name to avoid shadowing any variables named 95 // tmp. 96 #define RETURN_IF_NOT_OK_IMPL(tmp, stmt) \ 97 do { \ 98 ::android::netdutils::Status tmp = (stmt); \ 99 if (!isOk(tmp)) { \ 100 return tmp; \ 101 } \ 102 } while (false) 103 104 // Create a unique variable name to avoid shadowing local variables. 105 #define RETURN_IF_NOT_OK_CONCAT(line, stmt) RETURN_IF_NOT_OK_IMPL(__CONCAT(_status_, line), stmt) 106 107 // Macro to allow exception-like handling of error return values. 108 // 109 // If the evaluation of stmt results in an error, return that error 110 // from current function. 111 // 112 // Example usage: 113 // Status bar() { ... } 114 // 115 // RETURN_IF_NOT_OK(status); 116 // RETURN_IF_NOT_OK(bar()); 117 #define RETURN_IF_NOT_OK(stmt) RETURN_IF_NOT_OK_CONCAT(__LINE__, stmt) 118 119 } // namespace netdutils 120 } // namespace android 121 122 #endif /* NETUTILS_STATUS_H */ 123
