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 <cassert> 21 #include <ostream> 22 23 namespace android { 24 namespace netdutils { 25 26 // Simple status implementation suitable for use on the stack in low 27 // or moderate performance code. This can definitely be improved but 28 // for now short string optimization is expected to keep the common 29 // success case fast. 30 class Status { 31 public: 32 Status() = default; 33 34 Status(int code) : mCode(code) {} 35 36 Status(int code, const std::string& msg) : mCode(code), mMsg(msg) { assert(!ok()); } 37 38 int code() const { return mCode; } 39 40 bool ok() const { return code() == 0; } 41 42 const std::string& msg() const { return mMsg; } 43 44 bool operator==(const Status& other) const { return code() == other.code(); } 45 bool operator!=(const Status& other) const { return !(*this == other); } 46 47 private: 48 int mCode = 0; 49 std::string mMsg; 50 }; 51 52 namespace status { 53 54 const Status ok{0}; 55 // EOF is not part of errno space, we'll place it far above the 56 // highest existing value. 57 const Status eof{0x10001, "end of file"}; 58 const Status undefined{std::numeric_limits<int>::max(), "undefined"}; 59 60 } // namespace status 61 62 // Return true if status is "OK". This is sometimes preferable to 63 // status.ok() when we want to check the state of Status-like objects 64 // that implicitly cast to Status. 65 inline bool isOk(const Status& status) { 66 return status.ok(); 67 } 68 69 // Document that status is expected to be ok. This function may log 70 // (or assert when running in debug mode) if status has an unexpected 71 // value. 72 void expectOk(const Status& status); 73 74 // Convert POSIX errno to a Status object. 75 // If Status is extended to have more features, this mapping may 76 // become more complex. 77 Status statusFromErrno(int err, const std::string& msg); 78 79 // Helper that checks Status-like object (notably StatusOr) against a 80 // value in the errno space. 81 bool equalToErrno(const Status& status, int err); 82 83 // Helper that converts Status-like object (notably StatusOr) to a 84 // message. 85 std::string toString(const Status& status); 86 87 std::ostream& operator<<(std::ostream& os, const Status& s); 88 89 #define RETURN_IF_NOT_OK_IMPL(tmp, stmt) \ 90 do { \ 91 ::android::netdutils::Status tmp = (stmt); \ 92 if (!isOk(tmp)) { \ 93 return tmp; \ 94 } \ 95 } while (false) 96 97 #define RETURN_IF_NOT_OK_CONCAT(line, stmt) RETURN_IF_NOT_OK_IMPL(__CONCAT(_status_, line), stmt) 98 99 // Macro to allow exception-like handling of error return values. 100 // 101 // If the evaluation of stmt results in an error, return that error 102 // from current function. 103 // 104 // Example usage: 105 // Status bar() { ... } 106 // 107 // RETURN_IF_NOT_OK(status); 108 // RETURN_IF_NOT_OK(bar()); 109 #define RETURN_IF_NOT_OK(stmt) RETURN_IF_NOT_OK_CONCAT(__LINE__, stmt) 110 111 } // namespace netdutils 112 } // namespace android 113 114 #endif /* NETUTILS_STATUS_H */ 115
