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 "base/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 }  // namespace art
101 
102 #endif  // ART_CMDLINE_CMDLINE_RESULT_H_
103