1 /*
2  * Copyright (C) 2015 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 ART_CMDLINE_CMDLINE_RESULT_H_
18 #define ART_CMDLINE_CMDLINE_RESULT_H_
19 
20 #include <assert.h>
21 #include <utils.h>
22 
23 namespace art {
24   // Result of an attempt to process the command line arguments. If fails, specifies
25   // the specific error code and an error message.
26   // Use the value-carrying CmdlineParseResult<T> to get an additional value out in a success case.
27   struct CmdlineResult {
28     enum Status {
29       kSuccess,
30       // Error codes:
31       kUsage,
32       kFailure,
33       kOutOfRange,
34       kUnknown,
35     };
36 
37     // Short-hand for checking if the result was successful.
38     operator bool() const {
39       return IsSuccess();
40     }
41 
42     // Check if the operation has succeeded.
IsSuccessCmdlineResult43     bool IsSuccess() const { return status_ == kSuccess; }
44     // Check if the operation was not a success.
IsErrorCmdlineResult45     bool IsError() const { return status_ != kSuccess; }
46     // Get the specific status, regardless of whether it's failure or success.
GetStatusCmdlineResult47     Status GetStatus() const { return status_; }
48 
49     // Get the error message, *must* only be called for error status results.
GetMessageCmdlineResult50     const std::string& GetMessage() const { assert(IsError()); return message_; }
51 
52     // Constructor any status. No message.
CmdlineResultCmdlineResult53     explicit CmdlineResult(Status status) : status_(status) {}
54 
55     // Constructor with an error status, copying the message.
CmdlineResultCmdlineResult56     CmdlineResult(Status status, const std::string& message)
57       : status_(status), message_(message) {
58       assert(status != kSuccess);
59     }
60 
61     // Constructor with an error status, taking over the message.
CmdlineResultCmdlineResult62     CmdlineResult(Status status, std::string&& message)
63       : status_(status), message_(message) {
64       assert(status != kSuccess);
65     }
66 
67     // Make sure copying exists
68     CmdlineResult(const CmdlineResult&) = default;
69     // Make sure moving is cheap
70     CmdlineResult(CmdlineResult&&) = default;
71 
72   private:
73     const Status status_;
74     const std::string message_;
75   };
76 
77   // TODO: code-generate this
78   static inline std::ostream& operator<<(std::ostream& stream, CmdlineResult::Status status) {
79     switch (status) {
80       case CmdlineResult::kSuccess:
81         stream << "kSuccess";
82         break;
83       case CmdlineResult::kUsage:
84         stream << "kUsage";
85         break;
86       case CmdlineResult::kFailure:
87         stream << "kFailure";
88         break;
89       case CmdlineResult::kOutOfRange:
90         stream << "kOutOfRange";
91         break;
92       case CmdlineResult::kUnknown:
93         stream << "kUnknown";
94         break;
95       default:
96         UNREACHABLE();
97     }
98     return stream;
99   }
100 
101 }  // namespace art
102 
103 #endif  // ART_CMDLINE_CMDLINE_RESULT_H_
104