xref: /freebsd/contrib/llvm-project/libcxx/src/filesystem/directory_iterator.cpp (revision 770cf0a5f02dc8983a89c6568d741fbc25baa999)
1 //===----------------------------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include <__assert>
10 #include <__config>
11 #include <__memory/shared_ptr.h>
12 #include <errno.h>
13 #include <filesystem>
14 #include <stack>
15 #include <utility>
16 
17 #include "error.h"
18 #include "file_descriptor.h"
19 
20 #if defined(_LIBCPP_WIN32API)
21 #  define WIN32_LEAN_AND_MEAN
22 #  define NOMINMAX
23 #  include <windows.h>
24 #else
25 #  include <dirent.h> // for DIR & friends
26 #endif
27 
28 _LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
29 
30 using detail::ErrorHandler;
31 
32 #if defined(_LIBCPP_WIN32API)
33 class __dir_stream {
34 public:
35   __dir_stream()                               = delete;
36   __dir_stream& operator=(const __dir_stream&) = delete;
37 
38   __dir_stream(__dir_stream&& __ds) noexcept
39       : __stream_(__ds.__stream_), __root_(std::move(__ds.__root_)), __entry_(std::move(__ds.__entry_)) {
40     __ds.__stream_ = INVALID_HANDLE_VALUE;
41   }
42 
43   __dir_stream(const path& root, directory_options opts, error_code& ec)
44       : __stream_(INVALID_HANDLE_VALUE), __root_(root) {
45     if (root.native().empty()) {
46       ec = make_error_code(errc::no_such_file_or_directory);
47       return;
48     }
49     __stream_ = ::FindFirstFileW((root / "*").c_str(), &__data_);
50     if (__stream_ == INVALID_HANDLE_VALUE) {
51       ec                                  = detail::get_last_error();
52       const bool ignore_permission_denied = bool(opts & directory_options::skip_permission_denied);
53       if (ignore_permission_denied && ec == errc::permission_denied)
54         ec.clear();
55       return;
56     }
57     if (!assign())
58       advance(ec);
59   }
60 
61   ~__dir_stream() noexcept {
62     if (__stream_ == INVALID_HANDLE_VALUE)
63       return;
64     close();
65   }
66 
67   bool good() const noexcept { return __stream_ != INVALID_HANDLE_VALUE; }
68 
69   bool advance(error_code& ec) {
70     while (::FindNextFileW(__stream_, &__data_)) {
71       if (assign())
72         return true;
73     }
74     close();
75     return false;
76   }
77 
78   bool assign() {
79     if (!wcscmp(__data_.cFileName, L".") || !wcscmp(__data_.cFileName, L".."))
80       return false;
81     __entry_.__assign_iter_entry(
82         __root_ / __data_.cFileName,
83         directory_entry::__create_iter_cached_result(
84             detail::get_file_type(__data_),
85             detail::get_file_size(__data_),
86             detail::get_file_perm(__data_),
87             detail::get_write_time(__data_)));
88     return true;
89   }
90 
91 private:
92   error_code close() noexcept {
93     error_code ec;
94     if (!::FindClose(__stream_))
95       ec = detail::get_last_error();
96     __stream_ = INVALID_HANDLE_VALUE;
97     return ec;
98   }
99 
100   HANDLE __stream_{INVALID_HANDLE_VALUE};
101   WIN32_FIND_DATAW __data_;
102 
103 public:
104   path __root_;
105   directory_entry __entry_;
106 };
107 #else
108 class __dir_stream {
109 public:
110   __dir_stream()                               = delete;
111   __dir_stream& operator=(const __dir_stream&) = delete;
112 
113   __dir_stream(__dir_stream&& other) noexcept
114       : __stream_(other.__stream_), __root_(std::move(other.__root_)), __entry_(std::move(other.__entry_)) {
115     other.__stream_ = nullptr;
116   }
117 
118   __dir_stream(const path& root, directory_options opts, error_code& ec) : __stream_(nullptr), __root_(root) {
119     if ((__stream_ = ::opendir(root.c_str())) == nullptr) {
120       ec                      = detail::capture_errno();
121       const bool allow_eacces = bool(opts & directory_options::skip_permission_denied);
122       if (allow_eacces && ec == errc::permission_denied)
123         ec.clear();
124       return;
125     }
126     advance(ec);
127   }
128 
129   ~__dir_stream() noexcept {
130     if (__stream_)
131       close();
132   }
133 
134   bool good() const noexcept { return __stream_ != nullptr; }
135 
136   bool advance(error_code& ec) {
137     while (true) {
138       auto str_type_pair = detail::posix_readdir(__stream_, ec);
139       auto& str          = str_type_pair.first;
140       if (str == "." || str == "..") {
141         continue;
142       } else if (ec || str.empty()) {
143         close();
144         return false;
145       } else {
146         __entry_.__assign_iter_entry(__root_ / str, directory_entry::__create_iter_result(str_type_pair.second));
147         return true;
148       }
149     }
150   }
151 
152 private:
153   error_code close() noexcept {
154     error_code m_ec;
155     if (::closedir(__stream_) == -1)
156       m_ec = detail::capture_errno();
157     __stream_ = nullptr;
158     return m_ec;
159   }
160 
161   DIR* __stream_{nullptr};
162 
163 public:
164   path __root_;
165   directory_entry __entry_;
166 };
167 #endif
168 
169 // directory_iterator
170 
171 directory_iterator::directory_iterator(const path& p, error_code* ec, directory_options opts) {
172   ErrorHandler<void> err("directory_iterator::directory_iterator(...)", ec, &p);
173 
174   error_code m_ec;
175   __imp_ = make_shared<__dir_stream>(p, opts, m_ec);
176   if (ec)
177     *ec = m_ec;
178   if (!__imp_->good()) {
179     __imp_.reset();
180     if (m_ec)
181       err.report(m_ec);
182   }
183 }
184 
185 directory_iterator& directory_iterator::__increment(error_code* ec) {
186   _LIBCPP_ASSERT_NON_NULL(__imp_ != nullptr, "Attempting to increment an invalid iterator");
187   ErrorHandler<void> err("directory_iterator::operator++()", ec);
188 
189   error_code m_ec;
190   if (!__imp_->advance(m_ec)) {
191     path root = std::move(__imp_->__root_);
192     __imp_.reset();
193     if (m_ec)
194       err.report(m_ec, "at root " PATH_CSTR_FMT, root.c_str());
195   }
196   return *this;
197 }
198 
199 directory_entry const& directory_iterator::__dereference() const {
200   _LIBCPP_ASSERT_NON_NULL(__imp_ != nullptr, "Attempting to dereference an invalid iterator");
201   return __imp_->__entry_;
202 }
203 
204 // recursive_directory_iterator
205 
206 struct recursive_directory_iterator::__shared_imp {
207   stack<__dir_stream> __stack_;
208   directory_options __options_;
209 };
210 
211 recursive_directory_iterator::recursive_directory_iterator(const path& p, directory_options opt, error_code* ec)
212     : __imp_(nullptr), __rec_(true) {
213   ErrorHandler<void> err("recursive_directory_iterator", ec, &p);
214 
215   error_code m_ec;
216   __dir_stream new_s(p, opt, m_ec);
217   if (m_ec)
218     err.report(m_ec);
219   if (m_ec || !new_s.good())
220     return;
221 
222   __imp_             = make_shared<__shared_imp>();
223   __imp_->__options_ = opt;
224   __imp_->__stack_.push(std::move(new_s));
225 }
226 
227 void recursive_directory_iterator::__pop(error_code* ec) {
228   _LIBCPP_ASSERT_NON_NULL(__imp_ != nullptr, "Popping the end iterator");
229   if (ec)
230     ec->clear();
231   __imp_->__stack_.pop();
232   if (__imp_->__stack_.size() == 0)
233     __imp_.reset();
234   else
235     __advance(ec);
236 }
237 
238 directory_options recursive_directory_iterator::options() const { return __imp_->__options_; }
239 
240 int recursive_directory_iterator::depth() const { return __imp_->__stack_.size() - 1; }
241 
242 const directory_entry& recursive_directory_iterator::__dereference() const { return __imp_->__stack_.top().__entry_; }
243 
244 recursive_directory_iterator& recursive_directory_iterator::__increment(error_code* ec) {
245   if (ec)
246     ec->clear();
247   if (recursion_pending()) {
248     if (__try_recursion(ec) || (ec && *ec))
249       return *this;
250   }
251   __rec_ = true;
252   __advance(ec);
253   return *this;
254 }
255 
256 void recursive_directory_iterator::__advance(error_code* ec) {
257   ErrorHandler<void> err("recursive_directory_iterator::operator++()", ec);
258 
259   const directory_iterator end_it;
260   auto& stack = __imp_->__stack_;
261   error_code m_ec;
262   while (stack.size() > 0) {
263     if (stack.top().advance(m_ec))
264       return;
265     if (m_ec)
266       break;
267     stack.pop();
268   }
269 
270   if (m_ec) {
271     path root = std::move(stack.top().__root_);
272     __imp_.reset();
273     err.report(m_ec, "at root " PATH_CSTR_FMT, root.c_str());
274   } else {
275     __imp_.reset();
276   }
277 }
278 
279 bool recursive_directory_iterator::__try_recursion(error_code* ec) {
280   ErrorHandler<void> err("recursive_directory_iterator::operator++()", ec);
281 
282   bool rec_sym = bool(options() & directory_options::follow_directory_symlink);
283 
284   auto& curr_it = __imp_->__stack_.top();
285 
286   bool skip_rec = false;
287   error_code m_ec;
288   if (!rec_sym) {
289     file_status st(curr_it.__entry_.__get_sym_ft(&m_ec));
290     if (m_ec && status_known(st))
291       m_ec.clear();
292     if (m_ec || is_symlink(st) || !is_directory(st))
293       skip_rec = true;
294   } else {
295     file_status st(curr_it.__entry_.__get_ft(&m_ec));
296     if (m_ec && status_known(st))
297       m_ec.clear();
298     if (m_ec || !is_directory(st))
299       skip_rec = true;
300   }
301 
302   if (!skip_rec) {
303     __dir_stream new_it(curr_it.__entry_.path(), __imp_->__options_, m_ec);
304     if (new_it.good()) {
305       __imp_->__stack_.push(std::move(new_it));
306       return true;
307     }
308   }
309   if (m_ec) {
310     const bool allow_eacess = bool(__imp_->__options_ & directory_options::skip_permission_denied);
311     if (m_ec == errc::permission_denied && allow_eacess) {
312       if (ec)
313         ec->clear();
314     } else {
315       path at_ent = std::move(curr_it.__entry_.__p_);
316       __imp_.reset();
317       err.report(m_ec, "attempting recursion into " PATH_CSTR_FMT, at_ent.c_str());
318     }
319   }
320   return false;
321 }
322 
323 _LIBCPP_END_NAMESPACE_FILESYSTEM
324