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 24 namespace llvm { 25 namespace sys { 26 namespace path { 27 28 enum 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 52 class 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 64 public: 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 78 class 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 89 public: 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. 101 const_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. 106 const_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. 111 reverse_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. 116 reverse_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. 134 void 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. 148 void 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 173 bool 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. 187 void append(SmallVectorImpl<char> &path, const Twine &a, 188 const Twine &b = "", 189 const Twine &c = "", 190 const Twine &d = ""); 191 192 void 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. 206 void 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. 219 void 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. 227 void 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. 235 std::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 "". 251 StringRef 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 /// "". 264 StringRef 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 "". 272 StringRef 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 "". 284 StringRef 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 "". 296 StringRef 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. 310 StringRef 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. 328 StringRef 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. 344 StringRef 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 350 bool 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. 355 StringRef 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. 366 void 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. 372 bool 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. 379 bool 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. 386 bool 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. 394 bool 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. 402 bool 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. 410 bool 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. 418 bool 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. 426 bool 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. 434 bool 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. 442 bool 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. 450 bool 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. 469 bool 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. 494 bool 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. 500 bool 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. 506 StringRef 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 514 bool 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