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