1 /*
2 * Copyright (C) 2019 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 #pragma once
18
19 #include <iterator>
20 #include <optional>
21 #include <string>
22 #include <string_view>
23
24 #include <dirent.h>
25
26 namespace android::incfs::path {
27
28 namespace details {
29 void appendNextPath(std::string& res, std::string_view c);
30 }
31
32 constexpr auto procfsFdDir = std::string_view("/proc/self/fd");
33
34 std::string fromFd(int fd);
35 std::string procfsForFd(int fd);
36 std::string readlink(std::string_view path);
37 bool isAbsolute(std::string_view path);
38 std::string normalize(std::string_view path);
39
40 std::string_view relativize(std::string_view parent, std::string_view nested);
relativize(const char * parent,const char * nested)41 inline std::string_view relativize(const char* parent, const char* nested) {
42 return relativize(std::string_view(parent), std::string_view(nested));
43 }
relativize(std::string_view parent,const char * nested)44 inline std::string_view relativize(std::string_view parent, const char* nested) {
45 return relativize(parent, std::string_view(nested));
46 }
relativize(const char * parent,std::string_view nested)47 inline std::string_view relativize(const char* parent, std::string_view nested) {
48 return relativize(std::string_view(parent), nested);
49 }
50
51 std::string_view relativize(std::string&& parent, std::string_view nested) = delete;
52 std::string_view relativize(std::string_view parent, std::string&& nested) = delete;
53
54 // Note: some system headers #define 'dirname' and 'basename' as macros
55
baseName(std::string_view path)56 inline std::string_view baseName(std::string_view path) {
57 using namespace std::literals;
58 if (path.empty()) {
59 return {};
60 }
61 if (path == "/"sv) {
62 return "/"sv;
63 }
64 auto pos = path.rfind('/');
65 while (!path.empty() && pos == path.size() - 1) {
66 path.remove_suffix(1);
67 pos = path.rfind('/');
68 }
69 if (pos == path.npos) {
70 return path.empty() ? "/"sv : path;
71 }
72 return path.substr(pos + 1);
73 }
74
dirName(std::string_view path)75 inline std::string_view dirName(std::string_view path) {
76 using namespace std::literals;
77 if (path.empty()) {
78 return {};
79 }
80 if (path == "/"sv) {
81 return "/"sv;
82 }
83 const auto pos = path.rfind('/');
84 if (pos == 0) {
85 return "/"sv;
86 }
87 if (pos == path.npos) {
88 return "."sv;
89 }
90 return path.substr(0, pos);
91 }
92
93 // Split the |full| path into its directory and basename components.
94 // This modifies the input string to null-terminate the output directory
95 std::pair<std::string_view, std::string_view> splitDirBase(std::string& full);
96
97 int isEmptyDir(std::string_view dir);
98 bool startsWith(std::string_view path, std::string_view prefix);
99 bool endsWith(std::string_view path, std::string_view prefix);
100
101 struct PathDirCloser {
operatorPathDirCloser102 void operator()(DIR* d) const { ::closedir(d); }
103 };
104
openDir(const char * path)105 inline auto openDir(const char* path) {
106 auto dir = std::unique_ptr<DIR, PathDirCloser>(::opendir(path));
107 return dir;
108 }
109
openDir(int dirFd)110 inline auto openDir(int dirFd) {
111 auto dir = std::unique_ptr<DIR, PathDirCloser>(::fdopendir(dirFd));
112 return dir;
113 }
114
115 template <class... Paths>
join(std::string && first,std::string_view second,Paths &&...paths)116 std::string join(std::string&& first, std::string_view second, Paths&&... paths) {
117 std::string& result = first;
118 {
119 using std::size;
120 result.reserve(first.size() + second.size() + 1 + (sizeof...(paths) + ... + size(paths)));
121 }
122 (details::appendNextPath(result, second), ...,
123 details::appendNextPath(result, std::forward<Paths>(paths)));
124 return result;
125 }
126
127 template <class... Paths>
join(std::string_view first,std::string_view second,Paths &&...paths)128 std::string join(std::string_view first, std::string_view second, Paths&&... paths) {
129 return join(std::string(), first, second, std::forward<Paths>(paths)...);
130 }
131 template <class... Paths>
join(const char * first,std::string_view second,Paths &&...paths)132 std::string join(const char* first, std::string_view second, Paths&&... paths) {
133 return path::join(std::string_view(first), second, std::forward<Paths>(paths)...);
134 }
135
136 } // namespace android::incfs::path
137