1//===- llvm/Support/Path.h - Path Operating System Concept ------*- C++ -*-===//
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// This file declares the llvm::sys::path namespace. It is designed after
10// TR2/boost filesystem (v3), but modified to remove exception handling and the
11// path class.
12//
13//===----------------------------------------------------------------------===//
14
15#ifndef LLVM_SUPPORT_PATH_H
16#define LLVM_SUPPORT_PATH_H
17
18#include "llvm/ADT/Twine.h"
19#include "llvm/ADT/iterator.h"
20#include "llvm/Support/DataTypes.h"
21#include <iterator>
22
23namespace llvm {
24namespace sys {
25namespace path {
26
27enum class Style {
28 native,
29 posix,
30 windows_slash,
31 windows_backslash,
32 windows = windows_backslash, // deprecated
33};
34
35/// Check if \p S uses POSIX path rules.
36constexpr bool is_style_posix(Style S) {
37 if (S == Style::posix)
38 return true;
39 if (S != Style::native)
40 return false;
41#if defined(_WIN32)
42 return false;
43#else
44 return true;
45#endif
46}
47
48/// Check if \p S uses Windows path rules.
49constexpr bool is_style_windows(Style S) { return !is_style_posix(S); }
50
51/// @name Lexical Component Iterator
52/// @{
53
54/// Path iterator.
55///
56/// This is an input iterator that iterates over the individual components in
57/// \a path. The traversal order is as follows:
58/// * The root-name element, if present.
59/// * The root-directory element, if present.
60/// * Each successive filename element, if present.
61/// * Dot, if one or more trailing non-root slash characters are present.
62/// Traversing backwards is possible with \a reverse_iterator
63///
64/// Iteration examples. Each component is separated by ',':
65/// @code
66/// / => /
67/// /foo => /,foo
68/// foo/ => foo,.
69/// /foo/bar => /,foo,bar
70/// ../ => ..,.
71/// C:\foo\bar => C:,\,foo,bar
72/// @endcode
73class const_iterator
74 : public iterator_facade_base<const_iterator, std::input_iterator_tag,
75 const StringRef> {
76 StringRef Path; ///< The entire path.
77 StringRef Component; ///< The current component. Not necessarily in Path.
78 size_t Position = 0; ///< The iterators current position within Path.
79 Style S = Style::native; ///< The path style to use.
80
81 // An end iterator has Position = Path.size() + 1.
82 friend const_iterator begin(StringRef path, Style style);
83 friend const_iterator end(StringRef path);
84
85public:
86 reference operator*() const { return Component; }
87 const_iterator &operator++(); // preincrement
88 bool operator==(const const_iterator &RHS) const;
89
90 /// Difference in bytes between this and RHS.
91 ptrdiff_t operator-(const const_iterator &RHS) const;
92};
93
94/// Reverse path iterator.
95///
96/// This is an input iterator that iterates over the individual components in
97/// \a path in reverse order. The traversal order is exactly reversed from that
98/// of \a const_iterator
99class reverse_iterator
100 : public iterator_facade_base<reverse_iterator, std::input_iterator_tag,
101 const StringRef> {
102 StringRef Path; ///< The entire path.
103 StringRef Component; ///< The current component. Not necessarily in Path.
104 size_t Position = 0; ///< The iterators current position within Path.
105 Style S = Style::native; ///< The path style to use.
106
107 friend reverse_iterator rbegin(StringRef path, Style style);
108 friend reverse_iterator rend(StringRef path);
109
110public:
111 reference operator*() const { return Component; }
112 reverse_iterator &operator++(); // preincrement
113 bool operator==(const reverse_iterator &RHS) const;
114
115 /// Difference in bytes between this and RHS.
116 ptrdiff_t operator-(const reverse_iterator &RHS) const;
117};
118
119/// Get begin iterator over \a path.
120/// @param path Input path.
121/// @returns Iterator initialized with the first component of \a path.
122const_iterator begin(StringRef path, Style style = Style::native);
123
124/// Get end iterator over \a path.
125/// @param path Input path.
126/// @returns Iterator initialized to the end of \a path.
127const_iterator end(StringRef path);
128
129/// Get reverse begin iterator over \a path.
130/// @param path Input path.
131/// @returns Iterator initialized with the first reverse component of \a path.
132reverse_iterator rbegin(StringRef path, Style style = Style::native);
133
134/// Get reverse end iterator over \a path.
135/// @param path Input path.
136/// @returns Iterator initialized to the reverse end of \a path.
137reverse_iterator rend(StringRef path);
138
139/// @}
140/// @name Lexical Modifiers
141/// @{
142
143/// Remove the last component from \a path unless it is the root dir.
144///
145/// Similar to the POSIX "dirname" utility.
146///
147/// @code
148/// directory/filename.cpp => directory/
149/// directory/ => directory
150/// filename.cpp => <empty>
151/// / => /
152/// @endcode
153///
154/// @param path A path that is modified to not have a file component.
155void remove_filename(SmallVectorImpl<char> &path, Style style = Style::native);
156
157/// Replace the file extension of \a path with \a extension.
158///
159/// @code
160/// ./filename.cpp => ./filename.extension
161/// ./filename => ./filename.extension
162/// ./ => ./.extension
163/// @endcode
164///
165/// @param path A path that has its extension replaced with \a extension.
166/// @param extension The extension to be added. It may be empty. It may also
167/// optionally start with a '.', if it does not, one will be
168/// prepended.
169void replace_extension(SmallVectorImpl<char> &path, const Twine &extension,
170 Style style = Style::native);
171
172/// Replace matching path prefix with another path.
173///
174/// @code
175/// /foo, /old, /new => /foo
176/// /old, /old, /new => /new
177/// /old, /old/, /new => /old
178/// /old/foo, /old, /new => /new/foo
179/// /old/foo, /old/, /new => /new/foo
180/// /old/foo, /old/, /new/ => /new/foo
181/// /oldfoo, /old, /new => /oldfoo
182/// /foo, <empty>, /new => /new/foo
183/// /foo, <empty>, new => new/foo
184/// /old/foo, /old, <empty> => /foo
185/// @endcode
186///
187/// @param Path If \a Path starts with \a OldPrefix modify to instead
188/// start with \a NewPrefix.
189/// @param OldPrefix The path prefix to strip from \a Path.
190/// @param NewPrefix The path prefix to replace \a NewPrefix with.
191/// @param style The style used to match the prefix. Exact match using
192/// Posix style, case/separator insensitive match for Windows style.
193/// @result true if \a Path begins with OldPrefix
194bool replace_path_prefix(SmallVectorImpl<char> &Path, StringRef OldPrefix,
195 StringRef NewPrefix,
196 Style style = Style::native);
197
198/// Remove redundant leading "./" pieces and consecutive separators.
199///
200/// @param path Input path.
201/// @result The cleaned-up \a path.
202StringRef remove_leading_dotslash(StringRef path, Style style = Style::native);
203
204/// In-place remove any './' and optionally '../' components from a path.
205///
206/// @param path processed path
207/// @param remove_dot_dot specify if '../' (except for leading "../") should be
208/// removed
209/// @result True if path was changed
210bool remove_dots(SmallVectorImpl<char> &path, bool remove_dot_dot = false,
211 Style style = Style::native);
212
213/// Append to path.
214///
215/// @code
216/// /foo + bar/f => /foo/bar/f
217/// /foo/ + bar/f => /foo/bar/f
218/// foo + bar/f => foo/bar/f
219/// @endcode
220///
221/// @param path Set to \a path + \a component.
222/// @param a The component to be appended to \a path.
223void append(SmallVectorImpl<char> &path, const Twine &a,
224 const Twine &b = "",
225 const Twine &c = "",
226 const Twine &d = "");
227
228void append(SmallVectorImpl<char> &path, Style style, const Twine &a,
229 const Twine &b = "", const Twine &c = "", const Twine &d = "");
230
231/// Append to path.
232///
233/// @code
234/// /foo + [bar,f] => /foo/bar/f
235/// /foo/ + [bar,f] => /foo/bar/f
236/// foo + [bar,f] => foo/bar/f
237/// @endcode
238///
239/// @param path Set to \a path + [\a begin, \a end).
240/// @param begin Start of components to append.
241/// @param end One past the end of components to append.
242void append(SmallVectorImpl<char> &path, const_iterator begin,
243 const_iterator end, Style style = Style::native);
244
245/// @}
246/// @name Transforms (or some other better name)
247/// @{
248
249/// Convert path to the native form. This is used to give paths to users and
250/// operating system calls in the platform's normal way. For example, on Windows
251/// all '/' are converted to '\'. On Unix, it converts all '\' to '/'.
252///
253/// @param path A path that is transformed to native format.
254/// @param result Holds the result of the transformation.
255void native(const Twine &path, SmallVectorImpl<char> &result,
256 Style style = Style::native);
257
258/// Convert path to the native form in place. This is used to give paths to
259/// users and operating system calls in the platform's normal way. For example,
260/// on Windows all '/' are converted to '\'.
261///
262/// @param path A path that is transformed to native format.
263void native(SmallVectorImpl<char> &path, Style style = Style::native);
264
265/// For Windows path styles, convert path to use the preferred path separators.
266/// For other styles, do nothing.
267///
268/// @param path A path that is transformed to preferred format.
269inline void make_preferred(SmallVectorImpl<char> &path,
270 Style style = Style::native) {
271 if (!is_style_windows(style))
272 return;
273 native(path, style);
274}
275
276/// Replaces backslashes with slashes if Windows.
277///
278/// @param path processed path
279/// @result The result of replacing backslashes with forward slashes if Windows.
280/// On Unix, this function is a no-op because backslashes are valid path
281/// chracters.
282std::string convert_to_slash(StringRef path, Style style = Style::native);
283
284/// @}
285/// @name Lexical Observers
286/// @{
287
288/// Get root name.
289///
290/// @code
291/// //net/hello => //net
292/// c:/hello => c: (on Windows, on other platforms nothing)
293/// /hello => <empty>
294/// @endcode
295///
296/// @param path Input path.
297/// @result The root name of \a path if it has one, otherwise "".
298StringRef root_name(StringRef path, Style style = Style::native);
299
300/// Get root directory.
301///
302/// @code
303/// /goo/hello => /
304/// c:/hello => /
305/// d/file.txt => <empty>
306/// @endcode
307///
308/// @param path Input path.
309/// @result The root directory of \a path if it has one, otherwise
310/// "".
311StringRef root_directory(StringRef path, Style style = Style::native);
312
313/// Get root path.
314///
315/// Equivalent to root_name + root_directory.
316///
317/// @param path Input path.
318/// @result The root path of \a path if it has one, otherwise "".
319StringRef root_path(StringRef path, Style style = Style::native);
320
321/// Get relative path.
322///
323/// @code
324/// C:\hello\world => hello\world
325/// foo/bar => foo/bar
326/// /foo/bar => foo/bar
327/// @endcode
328///
329/// @param path Input path.
330/// @result The path starting after root_path if one exists, otherwise "".
331StringRef relative_path(StringRef path, Style style = Style::native);
332
333/// Get parent path.
334///
335/// @code
336/// / => <empty>
337/// /foo => /
338/// foo/../bar => foo/..
339/// @endcode
340///
341/// @param path Input path.
342/// @result The parent path of \a path if one exists, otherwise "".
343StringRef parent_path(StringRef path, Style style = Style::native);
344
345/// Get filename.
346///
347/// @code
348/// /foo.txt => foo.txt
349/// . => .
350/// .. => ..
351/// / => /
352/// @endcode
353///
354/// @param path Input path.
355/// @result The filename part of \a path. This is defined as the last component
356/// of \a path. Similar to the POSIX "basename" utility.
357StringRef filename(StringRef path, Style style = Style::native);
358
359/// Get stem.
360///
361/// If filename contains a dot but not solely one or two dots, result is the
362/// substring of filename ending at (but not including) the last dot. Otherwise
363/// it is filename.
364///
365/// @code
366/// /foo/bar.txt => bar
367/// /foo/bar => bar
368/// /foo/.txt => <empty>
369/// /foo/. => .
370/// /foo/.. => ..
371/// @endcode
372///
373/// @param path Input path.
374/// @result The stem of \a path.
375StringRef stem(StringRef path, Style style = Style::native);
376
377/// Get extension.
378///
379/// If filename contains a dot but not solely one or two dots, result is the
380/// substring of filename starting at (and including) the last dot, and ending
381/// at the end of \a path. Otherwise "".
382///
383/// @code
384/// /foo/bar.txt => .txt
385/// /foo/bar => <empty>
386/// /foo/.txt => .txt
387/// @endcode
388///
389/// @param path Input path.
390/// @result The extension of \a path.
391StringRef extension(StringRef path, Style style = Style::native);
392
393/// Check whether the given char is a path separator on the host OS.
394///
395/// @param value a character
396/// @result true if \a value is a path separator character on the host OS
397bool is_separator(char value, Style style = Style::native);
398
399/// Return the preferred separator for this platform.
400///
401/// @result StringRef of the preferred separator, null-terminated.
402StringRef get_separator(Style style = Style::native);
403
404/// Get the typical temporary directory for the system, e.g.,
405/// "/var/tmp" or "C:/TEMP"
406///
407/// @param erasedOnReboot Whether to favor a path that is erased on reboot
408/// rather than one that potentially persists longer. This parameter will be
409/// ignored if the user or system has set the typical environment variable
410/// (e.g., TEMP on Windows, TMPDIR on *nix) to specify a temporary directory.
411///
412/// @param result Holds the resulting path name.
413void system_temp_directory(bool erasedOnReboot, SmallVectorImpl<char> &result);
414
415/// Get the user's home directory.
416///
417/// @param result Holds the resulting path name.
418/// @result True if a home directory is set, false otherwise.
419bool home_directory(SmallVectorImpl<char> &result);
420
421/// Get the directory where packages should read user-specific configurations.
422/// e.g. $XDG_CONFIG_HOME.
423///
424/// @param result Holds the resulting path name.
425/// @result True if the appropriate path was determined, it need not exist.
426bool user_config_directory(SmallVectorImpl<char> &result);
427
428/// Get the directory where installed packages should put their
429/// machine-local cache, e.g. $XDG_CACHE_HOME.
430///
431/// @param result Holds the resulting path name.
432/// @result True if the appropriate path was determined, it need not exist.
433bool cache_directory(SmallVectorImpl<char> &result);
434
435/// Has root name?
436///
437/// root_name != ""
438///
439/// @param path Input path.
440/// @result True if the path has a root name, false otherwise.
441bool has_root_name(const Twine &path, Style style = Style::native);
442
443/// Has root directory?
444///
445/// root_directory != ""
446///
447/// @param path Input path.
448/// @result True if the path has a root directory, false otherwise.
449bool has_root_directory(const Twine &path, Style style = Style::native);
450
451/// Has root path?
452///
453/// root_path != ""
454///
455/// @param path Input path.
456/// @result True if the path has a root path, false otherwise.
457bool has_root_path(const Twine &path, Style style = Style::native);
458
459/// Has relative path?
460///
461/// relative_path != ""
462///
463/// @param path Input path.
464/// @result True if the path has a relative path, false otherwise.
465bool has_relative_path(const Twine &path, Style style = Style::native);
466
467/// Has parent path?
468///
469/// parent_path != ""
470///
471/// @param path Input path.
472/// @result True if the path has a parent path, false otherwise.
473bool has_parent_path(const Twine &path, Style style = Style::native);
474
475/// Has filename?
476///
477/// filename != ""
478///
479/// @param path Input path.
480/// @result True if the path has a filename, false otherwise.
481bool has_filename(const Twine &path, Style style = Style::native);
482
483/// Has stem?
484///
485/// stem != ""
486///
487/// @param path Input path.
488/// @result True if the path has a stem, false otherwise.
489bool has_stem(const Twine &path, Style style = Style::native);
490
491/// Has extension?
492///
493/// extension != ""
494///
495/// @param path Input path.
496/// @result True if the path has a extension, false otherwise.
497bool has_extension(const Twine &path, Style style = Style::native);
498
499/// Is path absolute?
500///
501/// According to cppreference.com, C++17 states: "An absolute path is a path
502/// that unambiguously identifies the location of a file without reference to
503/// an additional starting location."
504///
505/// In other words, the rules are:
506/// 1) POSIX style paths with nonempty root directory are absolute.
507/// 2) Windows style paths with nonempty root name and root directory are
508/// absolute.
509/// 3) No other paths are absolute.
510///
511/// \see has_root_name
512/// \see has_root_directory
513///
514/// @param path Input path.
515/// @result True if the path is absolute, false if it is not.
516bool is_absolute(const Twine &path, Style style = Style::native);
517
518/// Is path absolute using GNU rules?
519///
520/// GNU rules are:
521/// 1) Paths starting with a path separator are absolute.
522/// 2) Windows style paths are also absolute if they start with a character
523/// followed by ':'.
524/// 3) No other paths are absolute.
525///
526/// On Windows style the path "C:\Users\Default" has "C:" as root name and "\"
527/// as root directory.
528///
529/// Hence "C:" on Windows is absolute under GNU rules and not absolute under
530/// C++17 because it has no root directory. Likewise "/" and "\" on Windows are
531/// absolute under GNU and are not absolute under C++17 due to empty root name.
532///
533/// \see has_root_name
534/// \see has_root_directory
535///
536/// @param path Input path.
537/// @param style The style of \p path (e.g. Windows or POSIX). "native" style
538/// means to derive the style from the host.
539/// @result True if the path is absolute following GNU rules, false if it is
540/// not.
541bool is_absolute_gnu(const Twine &path, Style style = Style::native);
542
543/// Is path relative?
544///
545/// @param path Input path.
546/// @result True if the path is relative, false if it is not.
547bool is_relative(const Twine &path, Style style = Style::native);
548
549} // end namespace path
550} // end namespace sys
551} // end namespace llvm
552
553#endif
554

source code of llvm/include/llvm/Support/Path.h