1 //===--------------------- filesystem/path.cpp ----------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is dual licensed under the MIT and the University of Illinois Open
6 // Source Licenses. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
9 #include "experimental/filesystem"
10 #include "string_view"
13 namespace { namespace parser
16 using namespace std::experimental::filesystem;
18 using string_view_t = path::__string_view;
19 using string_view_pair = pair<string_view_t, string_view_t>;
20 using PosPtr = path::value_type const*;
23 enum ParserState : unsigned char {
24 // Zero is a special sentinel value used by default constructed iterators.
33 const string_view_t Path;
34 string_view_t RawEntry;
38 PathParser(string_view_t P, ParserState State) noexcept
39 : Path(P), State(State) {}
42 PathParser(string_view_t P, string_view_t E, unsigned char S)
43 : Path(P), RawEntry(E), State(static_cast<ParserState>(S)) {
44 // S cannot be '0' or PS_BeforeBegin.
47 static PathParser CreateBegin(string_view_t P) noexcept {
48 PathParser PP(P, PS_BeforeBegin);
53 static PathParser CreateEnd(string_view_t P) noexcept {
54 PathParser PP(P, PS_AtEnd);
58 PosPtr peek() const noexcept {
59 auto TkEnd = getNextTokenStartPos();
60 auto End = getAfterBack();
61 return TkEnd == End ? nullptr : TkEnd;
64 void increment() noexcept {
65 const PosPtr End = getAfterBack();
66 const PosPtr Start = getNextTokenStartPos();
68 return makeState(PS_AtEnd);
71 case PS_BeforeBegin: {
72 PosPtr TkEnd = consumeSeparator(Start, End);
73 // If we consumed exactly two separators we have a root name.
74 if (TkEnd && TkEnd == Start + 2) {
75 // FIXME Do we need to consume a name or is '//' a root name on its own?
76 // what about '//.', '//..', '//...'?
77 auto NameEnd = consumeName(TkEnd, End);
80 return makeState(PS_InRootName, Start, TkEnd);
83 return makeState(PS_InRootDir, Start, TkEnd);
85 return makeState(PS_InFilenames, Start, consumeName(Start, End));
89 return makeState(PS_InRootDir, Start, consumeSeparator(Start, End));
91 return makeState(PS_InFilenames, Start, consumeName(Start, End));
93 case PS_InFilenames: {
94 PosPtr SepEnd = consumeSeparator(Start, End);
96 PosPtr TkEnd = consumeName(SepEnd, End);
98 return makeState(PS_InFilenames, SepEnd, TkEnd);
100 return makeState(PS_InTrailingSep, Start, SepEnd);
103 case PS_InTrailingSep:
104 return makeState(PS_AtEnd);
107 _LIBCPP_UNREACHABLE();
111 void decrement() noexcept {
112 const PosPtr REnd = getBeforeFront();
113 const PosPtr RStart = getCurrentTokenStartPos() - 1;
117 // Try to consume a trailing separator or root directory first.
118 if (PosPtr SepEnd = consumeSeparator(RStart, REnd)) {
120 return makeState((RStart == REnd + 2) ? PS_InRootName : PS_InRootDir,
121 Path.data(), RStart + 1);
122 // Check if we're seeing the root directory separator
123 auto PP = CreateBegin(Path);
124 bool InRootDir = PP.State == PS_InRootName &&
125 &PP.RawEntry.back() == SepEnd;
126 return makeState(InRootDir ? PS_InRootDir : PS_InTrailingSep,
127 SepEnd + 1, RStart + 1);
129 PosPtr TkStart = consumeName(RStart, REnd);
130 if (TkStart == REnd + 2 && consumeSeparator(TkStart, REnd) == REnd)
131 return makeState(PS_InRootName, Path.data(), RStart + 1);
133 return makeState(PS_InFilenames, TkStart + 1, RStart + 1);
136 case PS_InTrailingSep:
137 return makeState(PS_InFilenames, consumeName(RStart, REnd) + 1, RStart + 1);
138 case PS_InFilenames: {
139 PosPtr SepEnd = consumeSeparator(RStart, REnd);
141 return makeState((RStart == REnd + 2) ? PS_InRootName : PS_InRootDir,
142 Path.data(), RStart + 1);
143 PosPtr TkEnd = consumeName(SepEnd, REnd);
144 if (TkEnd == REnd + 2 && consumeSeparator(TkEnd, REnd) == REnd)
145 return makeState(PS_InRootDir, SepEnd + 1, RStart + 1);
146 return makeState(PS_InFilenames, TkEnd + 1, SepEnd + 1);
149 return makeState(PS_InRootName, Path.data(), RStart + 1);
152 _LIBCPP_UNREACHABLE();
156 /// \brief Return a view with the "preferred representation" of the current
157 /// element. For example trailing separators are represented as a '.'
158 string_view_t operator*() const noexcept {
165 case PS_InTrailingSep:
171 _LIBCPP_UNREACHABLE();
174 explicit operator bool() const noexcept {
175 return State != PS_BeforeBegin && State != PS_AtEnd;
178 PathParser& operator++() noexcept {
183 PathParser& operator--() noexcept {
189 void makeState(ParserState NewState, PosPtr Start, PosPtr End) noexcept {
191 RawEntry = string_view_t(Start, End - Start);
193 void makeState(ParserState NewState) noexcept {
198 PosPtr getAfterBack() const noexcept {
199 return Path.data() + Path.size();
202 PosPtr getBeforeFront() const noexcept {
203 return Path.data() - 1;
206 /// \brief Return a pointer to the first character after the currently
208 PosPtr getNextTokenStartPos() const noexcept {
215 return &RawEntry.back() + 1;
216 case PS_InTrailingSep:
218 return getAfterBack();
220 _LIBCPP_UNREACHABLE();
223 /// \brief Return a pointer to the first character in the currently lexed
225 PosPtr getCurrentTokenStartPos() const noexcept {
229 return &Path.front();
232 case PS_InTrailingSep:
233 return &RawEntry.front();
235 return &Path.back() + 1;
237 _LIBCPP_UNREACHABLE();
240 PosPtr consumeSeparator(PosPtr P, PosPtr End) const noexcept {
241 if (P == End || *P != '/')
243 const int Inc = P < End ? 1 : -1;
245 while (P != End && *P == '/')
250 PosPtr consumeName(PosPtr P, PosPtr End) const noexcept {
251 if (P == End || *P == '/')
253 const int Inc = P < End ? 1 : -1;
255 while (P != End && *P != '/')
261 string_view_pair separate_filename(string_view_t const & s) {
262 if (s == "." || s == ".." || s.empty()) return string_view_pair{s, ""};
263 auto pos = s.find_last_of('.');
264 if (pos == string_view_t::npos) return string_view_pair{s, string_view{}};
265 return string_view_pair{s.substr(0, pos), s.substr(pos)};
268 string_view_t createView(PosPtr S, PosPtr E) noexcept {
269 return {S, static_cast<size_t>(E - S) + 1};
272 }} // namespace parser
274 _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL_FILESYSTEM
276 using parser::string_view_t;
277 using parser::string_view_pair;
278 using parser::PathParser;
279 using parser::createView;
281 ///////////////////////////////////////////////////////////////////////////////
283 ///////////////////////////////////////////////////////////////////////////////
285 constexpr path::value_type path::preferred_separator;
287 path & path::replace_extension(path const & replacement)
289 path p = extension();
291 __pn_.erase(__pn_.size() - p.native().size());
293 if (!replacement.empty()) {
294 if (replacement.native()[0] != '.') {
297 __pn_.append(replacement.__pn_);
302 ///////////////////////////////////////////////////////////////////////////////
305 string_view_t path::__root_name() const
307 auto PP = PathParser::CreateBegin(__pn_);
308 if (PP.State == PathParser::PS_InRootName)
313 string_view_t path::__root_directory() const
315 auto PP = PathParser::CreateBegin(__pn_);
316 if (PP.State == PathParser::PS_InRootName)
318 if (PP.State == PathParser::PS_InRootDir)
323 string_view_t path::__root_path_raw() const
325 auto PP = PathParser::CreateBegin(__pn_);
326 if (PP.State == PathParser::PS_InRootName) {
327 auto NextCh = PP.peek();
328 if (NextCh && *NextCh == '/') {
330 return createView(__pn_.data(), &PP.RawEntry.back());
334 if (PP.State == PathParser::PS_InRootDir)
339 string_view_t path::__relative_path() const
341 auto PP = PathParser::CreateBegin(__pn_);
342 while (PP.State <= PathParser::PS_InRootDir)
344 if (PP.State == PathParser::PS_AtEnd)
346 return createView(PP.RawEntry.data(), &__pn_.back());
349 string_view_t path::__parent_path() const
353 auto PP = PathParser::CreateEnd(__pn_);
355 if (PP.RawEntry.data() == __pn_.data())
358 return createView(__pn_.data(), &PP.RawEntry.back());
361 string_view_t path::__filename() const
363 if (empty()) return {};
364 return *(--PathParser::CreateEnd(__pn_));
367 string_view_t path::__stem() const
369 return parser::separate_filename(__filename()).first;
372 string_view_t path::__extension() const
374 return parser::separate_filename(__filename()).second;
377 ////////////////////////////////////////////////////////////////////////////
379 int path::__compare(string_view_t __s) const {
380 auto PP = PathParser::CreateBegin(__pn_);
381 auto PP2 = PathParser::CreateBegin(__s);
383 int res = (*PP).compare(*PP2);
384 if (res != 0) return res;
387 if (PP.State == PP2.State && PP.State == PathParser::PS_AtEnd)
389 if (PP.State == PathParser::PS_AtEnd)
394 ////////////////////////////////////////////////////////////////////////////
396 size_t hash_value(const path& __p) noexcept {
397 auto PP = PathParser::CreateBegin(__p.native());
398 size_t hash_value = 0;
399 std::hash<string_view> hasher;
401 hash_value = __hash_combine(hash_value, hasher(*PP));
407 ////////////////////////////////////////////////////////////////////////////
409 path::iterator path::begin() const
411 auto PP = PathParser::CreateBegin(__pn_);
413 it.__path_ptr_ = this;
414 it.__state_ = PP.State;
415 it.__entry_ = PP.RawEntry;
416 it.__stashed_elem_.__assign_view(*PP);
420 path::iterator path::end() const
423 it.__state_ = PathParser::PS_AtEnd;
424 it.__path_ptr_ = this;
428 path::iterator& path::iterator::__increment() {
429 static_assert(__at_end == PathParser::PS_AtEnd, "");
430 PathParser PP(__path_ptr_->native(), __entry_, __state_);
433 __entry_ = PP.RawEntry;
434 __stashed_elem_.__assign_view(*PP);
438 path::iterator& path::iterator::__decrement() {
439 PathParser PP(__path_ptr_->native(), __entry_, __state_);
442 __entry_ = PP.RawEntry;
443 __stashed_elem_.__assign_view(*PP);
447 _LIBCPP_END_NAMESPACE_EXPERIMENTAL_FILESYSTEM