1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
|
/*
* Copyright (C) 2015 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#pragma once
#include <map>
#include <string>
#include <vector>
#include "result.h"
namespace android {
namespace init {
// Every init builtin, init service option, and ueventd option has a minimum and maximum number of
// arguments. These must be checked both at run time for safety and also at build time for
// correctness in host_init_verifier. Instead of copying and pasting the boiler plate code that
// does this check into each function, it is abstracted in KeywordMap<>. This class maps keywords
// to functions and checks that the number of arguments provided falls in the correct range or
// returns an error otherwise.
// Value is the return value of Find(), which is typically either a single function or a struct with
// additional information.
template <typename Value>
class KeywordMap {
public:
struct MapValue {
size_t min_args;
size_t max_args;
Value value;
};
KeywordMap() {}
KeywordMap(std::initializer_list<std::pair<const std::string, MapValue>> init) : map_(init) {}
Result<Value> Find(const std::vector<std::string>& args) const {
if (args.empty()) return Error() << "Keyword needed, but not provided";
auto& keyword = args[0];
auto num_args = args.size() - 1;
auto result_it = map_.find(keyword);
if (result_it == map_.end()) {
return Errorf("Invalid keyword '{}'", keyword);
}
auto result = result_it->second;
auto min_args = result.min_args;
auto max_args = result.max_args;
if (min_args == max_args && num_args != min_args) {
return Errorf("{} requires {} argument{}", keyword, min_args,
(min_args > 1 || min_args == 0) ? "s" : "");
}
if (num_args < min_args || num_args > max_args) {
if (max_args == std::numeric_limits<decltype(max_args)>::max()) {
return Errorf("{} requires at least {} argument{}", keyword, min_args,
min_args > 1 ? "s" : "");
} else {
return Errorf("{} requires between {} and {} arguments", keyword, min_args,
max_args);
}
}
return result.value;
}
private:
std::map<std::string, MapValue> map_;
};
} // namespace init
} // namespace android
|
