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      1 //===- llvm/Support/FileSystem.h - File System OS Concept -------*- C++ -*-===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // This file declares the llvm::sys::fs namespace. It is designed after
     11 // TR2/boost filesystem (v3), but modified to remove exception handling and the
     12 // path class.
     13 //
     14 // All functions return an error_code and their actual work via the last out
     15 // argument. The out argument is defined if and only if errc::success is
     16 // returned. A function may return any error code in the generic or system
     17 // category. However, they shall be equivalent to any error conditions listed
     18 // in each functions respective documentation if the condition applies. [ note:
     19 // this does not guarantee that error_code will be in the set of explicitly
     20 // listed codes, but it does guarantee that if any of the explicitly listed
     21 // errors occur, the correct error_code will be used ]. All functions may
     22 // return errc::not_enough_memory if there is not enough memory to complete the
     23 // operation.
     24 //
     25 //===----------------------------------------------------------------------===//
     26 
     27 #ifndef LLVM_SUPPORT_FILESYSTEM_H
     28 #define LLVM_SUPPORT_FILESYSTEM_H
     29 
     30 #include "llvm/ADT/IntrusiveRefCntPtr.h"
     31 #include "llvm/ADT/SmallString.h"
     32 #include "llvm/ADT/StringRef.h"
     33 #include "llvm/ADT/Twine.h"
     34 #include "llvm/Support/DataTypes.h"
     35 #include "llvm/Support/ErrorHandling.h"
     36 #include "llvm/Support/ErrorOr.h"
     37 #include "llvm/Support/TimeValue.h"
     38 #include <cassert>
     39 #include <cstdint>
     40 #include <ctime>
     41 #include <stack>
     42 #include <string>
     43 #include <system_error>
     44 #include <tuple>
     45 #include <vector>
     46 
     47 #ifdef HAVE_SYS_STAT_H
     48 #include <sys/stat.h>
     49 #endif
     50 
     51 namespace llvm {
     52 namespace sys {
     53 namespace fs {
     54 
     55 /// An enumeration for the file system's view of the type.
     56 enum class file_type {
     57   status_error,
     58   file_not_found,
     59   regular_file,
     60   directory_file,
     61   symlink_file,
     62   block_file,
     63   character_file,
     64   fifo_file,
     65   socket_file,
     66   type_unknown
     67 };
     68 
     69 /// space_info - Self explanatory.
     70 struct space_info {
     71   uint64_t capacity;
     72   uint64_t free;
     73   uint64_t available;
     74 };
     75 
     76 enum perms {
     77   no_perms = 0,
     78   owner_read = 0400,
     79   owner_write = 0200,
     80   owner_exe = 0100,
     81   owner_all = owner_read | owner_write | owner_exe,
     82   group_read = 040,
     83   group_write = 020,
     84   group_exe = 010,
     85   group_all = group_read | group_write | group_exe,
     86   others_read = 04,
     87   others_write = 02,
     88   others_exe = 01,
     89   others_all = others_read | others_write | others_exe,
     90   all_read = owner_read | group_read | others_read,
     91   all_write = owner_write | group_write | others_write,
     92   all_exe = owner_exe | group_exe | others_exe,
     93   all_all = owner_all | group_all | others_all,
     94   set_uid_on_exe = 04000,
     95   set_gid_on_exe = 02000,
     96   sticky_bit = 01000,
     97   perms_not_known = 0xFFFF
     98 };
     99 
    100 // Helper functions so that you can use & and | to manipulate perms bits:
    101 inline perms operator|(perms l, perms r) {
    102   return static_cast<perms>(static_cast<unsigned short>(l) |
    103                             static_cast<unsigned short>(r));
    104 }
    105 inline perms operator&(perms l, perms r) {
    106   return static_cast<perms>(static_cast<unsigned short>(l) &
    107                             static_cast<unsigned short>(r));
    108 }
    109 inline perms &operator|=(perms &l, perms r) {
    110   l = l | r;
    111   return l;
    112 }
    113 inline perms &operator&=(perms &l, perms r) {
    114   l = l & r;
    115   return l;
    116 }
    117 inline perms operator~(perms x) {
    118   return static_cast<perms>(~static_cast<unsigned short>(x));
    119 }
    120 
    121 class UniqueID {
    122   uint64_t Device;
    123   uint64_t File;
    124 
    125 public:
    126   UniqueID() = default;
    127   UniqueID(uint64_t Device, uint64_t File) : Device(Device), File(File) {}
    128   bool operator==(const UniqueID &Other) const {
    129     return Device == Other.Device && File == Other.File;
    130   }
    131   bool operator!=(const UniqueID &Other) const { return !(*this == Other); }
    132   bool operator<(const UniqueID &Other) const {
    133     return std::tie(Device, File) < std::tie(Other.Device, Other.File);
    134   }
    135   uint64_t getDevice() const { return Device; }
    136   uint64_t getFile() const { return File; }
    137 };
    138 
    139 /// file_status - Represents the result of a call to stat and friends. It has
    140 ///               a platform-specific member to store the result.
    141 class file_status
    142 {
    143   #if defined(LLVM_ON_UNIX)
    144   dev_t fs_st_dev;
    145   ino_t fs_st_ino;
    146   time_t fs_st_atime;
    147   time_t fs_st_mtime;
    148   uid_t fs_st_uid;
    149   gid_t fs_st_gid;
    150   off_t fs_st_size;
    151   #elif defined (LLVM_ON_WIN32)
    152   uint32_t LastAccessedTimeHigh;
    153   uint32_t LastAccessedTimeLow;
    154   uint32_t LastWriteTimeHigh;
    155   uint32_t LastWriteTimeLow;
    156   uint32_t VolumeSerialNumber;
    157   uint32_t FileSizeHigh;
    158   uint32_t FileSizeLow;
    159   uint32_t FileIndexHigh;
    160   uint32_t FileIndexLow;
    161   #endif
    162   friend bool equivalent(file_status A, file_status B);
    163   file_type Type;
    164   perms Perms;
    165 
    166 public:
    167   #if defined(LLVM_ON_UNIX)
    168   file_status()
    169       : fs_st_dev(0), fs_st_ino(0), fs_st_atime(0), fs_st_mtime(0),
    170         fs_st_uid(0), fs_st_gid(0), fs_st_size(0),
    171         Type(file_type::status_error), Perms(perms_not_known) {}
    172 
    173   file_status(file_type Type)
    174       : fs_st_dev(0), fs_st_ino(0), fs_st_atime(0), fs_st_mtime(0),
    175         fs_st_uid(0), fs_st_gid(0), fs_st_size(0), Type(Type),
    176         Perms(perms_not_known) {}
    177 
    178   file_status(file_type Type, perms Perms, dev_t Dev, ino_t Ino, time_t ATime,
    179               time_t MTime, uid_t UID, gid_t GID, off_t Size)
    180       : fs_st_dev(Dev), fs_st_ino(Ino), fs_st_atime(ATime), fs_st_mtime(MTime),
    181         fs_st_uid(UID), fs_st_gid(GID), fs_st_size(Size), Type(Type),
    182         Perms(Perms) {}
    183   #elif defined(LLVM_ON_WIN32)
    184   file_status()
    185       : LastAccessedTimeHigh(0), LastAccessedTimeLow(0), LastWriteTimeHigh(0),
    186         LastWriteTimeLow(0), VolumeSerialNumber(0), FileSizeHigh(0),
    187         FileSizeLow(0), FileIndexHigh(0), FileIndexLow(0),
    188         Type(file_type::status_error), Perms(perms_not_known) {}
    189 
    190   file_status(file_type Type)
    191       : LastAccessedTimeHigh(0), LastAccessedTimeLow(0), LastWriteTimeHigh(0),
    192         LastWriteTimeLow(0), VolumeSerialNumber(0), FileSizeHigh(0),
    193         FileSizeLow(0), FileIndexHigh(0), FileIndexLow(0), Type(Type),
    194         Perms(perms_not_known) {}
    195 
    196   file_status(file_type Type, uint32_t LastAccessTimeHigh,
    197               uint32_t LastAccessTimeLow, uint32_t LastWriteTimeHigh,
    198               uint32_t LastWriteTimeLow, uint32_t VolumeSerialNumber,
    199               uint32_t FileSizeHigh, uint32_t FileSizeLow,
    200               uint32_t FileIndexHigh, uint32_t FileIndexLow)
    201       : LastAccessedTimeHigh(LastAccessTimeHigh), LastAccessedTimeLow(LastAccessTimeLow),
    202         LastWriteTimeHigh(LastWriteTimeHigh),
    203         LastWriteTimeLow(LastWriteTimeLow),
    204         VolumeSerialNumber(VolumeSerialNumber), FileSizeHigh(FileSizeHigh),
    205         FileSizeLow(FileSizeLow), FileIndexHigh(FileIndexHigh),
    206         FileIndexLow(FileIndexLow), Type(Type), Perms(perms_not_known) {}
    207   #endif
    208 
    209   // getters
    210   file_type type() const { return Type; }
    211   perms permissions() const { return Perms; }
    212   TimeValue getLastAccessedTime() const;
    213   TimeValue getLastModificationTime() const;
    214   UniqueID getUniqueID() const;
    215 
    216   #if defined(LLVM_ON_UNIX)
    217   uint32_t getUser() const { return fs_st_uid; }
    218   uint32_t getGroup() const { return fs_st_gid; }
    219   uint64_t getSize() const { return fs_st_size; }
    220   #elif defined (LLVM_ON_WIN32)
    221   uint32_t getUser() const {
    222     return 9999; // Not applicable to Windows, so...
    223   }
    224   uint32_t getGroup() const {
    225     return 9999; // Not applicable to Windows, so...
    226   }
    227   uint64_t getSize() const {
    228     return (uint64_t(FileSizeHigh) << 32) + FileSizeLow;
    229   }
    230   #endif
    231 
    232   // setters
    233   void type(file_type v) { Type = v; }
    234   void permissions(perms p) { Perms = p; }
    235 };
    236 
    237 /// file_magic - An "enum class" enumeration of file types based on magic (the first
    238 ///         N bytes of the file).
    239 struct file_magic {
    240   enum Impl {
    241     unknown = 0,              ///< Unrecognized file
    242     bitcode,                  ///< Bitcode file
    243     archive,                  ///< ar style archive file
    244     elf,                      ///< ELF Unknown type
    245     elf_relocatable,          ///< ELF Relocatable object file
    246     elf_executable,           ///< ELF Executable image
    247     elf_shared_object,        ///< ELF dynamically linked shared lib
    248     elf_core,                 ///< ELF core image
    249     macho_object,             ///< Mach-O Object file
    250     macho_executable,         ///< Mach-O Executable
    251     macho_fixed_virtual_memory_shared_lib, ///< Mach-O Shared Lib, FVM
    252     macho_core,               ///< Mach-O Core File
    253     macho_preload_executable, ///< Mach-O Preloaded Executable
    254     macho_dynamically_linked_shared_lib, ///< Mach-O dynlinked shared lib
    255     macho_dynamic_linker,     ///< The Mach-O dynamic linker
    256     macho_bundle,             ///< Mach-O Bundle file
    257     macho_dynamically_linked_shared_lib_stub, ///< Mach-O Shared lib stub
    258     macho_dsym_companion,     ///< Mach-O dSYM companion file
    259     macho_kext_bundle,        ///< Mach-O kext bundle file
    260     macho_universal_binary,   ///< Mach-O universal binary
    261     coff_object,              ///< COFF object file
    262     coff_import_library,      ///< COFF import library
    263     pecoff_executable,        ///< PECOFF executable file
    264     windows_resource          ///< Windows compiled resource file (.rc)
    265   };
    266 
    267   bool is_object() const {
    268     return V != unknown;
    269   }
    270 
    271   file_magic() : V(unknown) {}
    272   file_magic(Impl V) : V(V) {}
    273   operator Impl() const { return V; }
    274 
    275 private:
    276   Impl V;
    277 };
    278 
    279 /// @}
    280 /// @name Physical Operators
    281 /// @{
    282 
    283 /// @brief Make \a path an absolute path.
    284 ///
    285 /// Makes \a path absolute using the \a current_directory if it is not already.
    286 /// An empty \a path will result in the \a current_directory.
    287 ///
    288 /// /absolute/path   => /absolute/path
    289 /// relative/../path => <current-directory>/relative/../path
    290 ///
    291 /// @param path A path that is modified to be an absolute path.
    292 /// @returns errc::success if \a path has been made absolute, otherwise a
    293 ///          platform-specific error_code.
    294 std::error_code make_absolute(const Twine &current_directory,
    295                               SmallVectorImpl<char> &path);
    296 
    297 /// @brief Make \a path an absolute path.
    298 ///
    299 /// Makes \a path absolute using the current directory if it is not already. An
    300 /// empty \a path will result in the current directory.
    301 ///
    302 /// /absolute/path   => /absolute/path
    303 /// relative/../path => <current-directory>/relative/../path
    304 ///
    305 /// @param path A path that is modified to be an absolute path.
    306 /// @returns errc::success if \a path has been made absolute, otherwise a
    307 ///          platform-specific error_code.
    308 std::error_code make_absolute(SmallVectorImpl<char> &path);
    309 
    310 /// @brief Create all the non-existent directories in path.
    311 ///
    312 /// @param path Directories to create.
    313 /// @returns errc::success if is_directory(path), otherwise a platform
    314 ///          specific error_code. If IgnoreExisting is false, also returns
    315 ///          error if the directory already existed.
    316 std::error_code create_directories(const Twine &path,
    317                                    bool IgnoreExisting = true,
    318                                    perms Perms = owner_all | group_all);
    319 
    320 /// @brief Create the directory in path.
    321 ///
    322 /// @param path Directory to create.
    323 /// @returns errc::success if is_directory(path), otherwise a platform
    324 ///          specific error_code. If IgnoreExisting is false, also returns
    325 ///          error if the directory already existed.
    326 std::error_code create_directory(const Twine &path, bool IgnoreExisting = true,
    327                                  perms Perms = owner_all | group_all);
    328 
    329 /// @brief Create a link from \a from to \a to.
    330 ///
    331 /// The link may be a soft or a hard link, depending on the platform. The caller
    332 /// may not assume which one. Currently on windows it creates a hard link since
    333 /// soft links require extra privileges. On unix, it creates a soft link since
    334 /// hard links don't work on SMB file systems.
    335 ///
    336 /// @param to The path to hard link to.
    337 /// @param from The path to hard link from. This is created.
    338 /// @returns errc::success if the link was created, otherwise a platform
    339 /// specific error_code.
    340 std::error_code create_link(const Twine &to, const Twine &from);
    341 
    342 /// @brief Get the current path.
    343 ///
    344 /// @param result Holds the current path on return.
    345 /// @returns errc::success if the current path has been stored in result,
    346 ///          otherwise a platform-specific error_code.
    347 std::error_code current_path(SmallVectorImpl<char> &result);
    348 
    349 /// @brief Remove path. Equivalent to POSIX remove().
    350 ///
    351 /// @param path Input path.
    352 /// @returns errc::success if path has been removed or didn't exist, otherwise a
    353 ///          platform-specific error code. If IgnoreNonExisting is false, also
    354 ///          returns error if the file didn't exist.
    355 std::error_code remove(const Twine &path, bool IgnoreNonExisting = true);
    356 
    357 /// @brief Rename \a from to \a to. Files are renamed as if by POSIX rename().
    358 ///
    359 /// @param from The path to rename from.
    360 /// @param to The path to rename to. This is created.
    361 std::error_code rename(const Twine &from, const Twine &to);
    362 
    363 /// @brief Copy the contents of \a From to \a To.
    364 ///
    365 /// @param From The path to copy from.
    366 /// @param To The path to copy to. This is created.
    367 std::error_code copy_file(const Twine &From, const Twine &To);
    368 
    369 /// @brief Resize path to size. File is resized as if by POSIX truncate().
    370 ///
    371 /// @param FD Input file descriptor.
    372 /// @param Size Size to resize to.
    373 /// @returns errc::success if \a path has been resized to \a size, otherwise a
    374 ///          platform-specific error_code.
    375 std::error_code resize_file(int FD, uint64_t Size);
    376 
    377 /// @}
    378 /// @name Physical Observers
    379 /// @{
    380 
    381 /// @brief Does file exist?
    382 ///
    383 /// @param status A file_status previously returned from stat.
    384 /// @returns True if the file represented by status exists, false if it does
    385 ///          not.
    386 bool exists(file_status status);
    387 
    388 enum class AccessMode { Exist, Write, Execute };
    389 
    390 /// @brief Can the file be accessed?
    391 ///
    392 /// @param Path Input path.
    393 /// @returns errc::success if the path can be accessed, otherwise a
    394 ///          platform-specific error_code.
    395 std::error_code access(const Twine &Path, AccessMode Mode);
    396 
    397 /// @brief Does file exist?
    398 ///
    399 /// @param Path Input path.
    400 /// @returns True if it exists, false otherwise.
    401 inline bool exists(const Twine &Path) {
    402   return !access(Path, AccessMode::Exist);
    403 }
    404 
    405 /// @brief Can we execute this file?
    406 ///
    407 /// @param Path Input path.
    408 /// @returns True if we can execute it, false otherwise.
    409 bool can_execute(const Twine &Path);
    410 
    411 /// @brief Can we write this file?
    412 ///
    413 /// @param Path Input path.
    414 /// @returns True if we can write to it, false otherwise.
    415 inline bool can_write(const Twine &Path) {
    416   return !access(Path, AccessMode::Write);
    417 }
    418 
    419 /// @brief Do file_status's represent the same thing?
    420 ///
    421 /// @param A Input file_status.
    422 /// @param B Input file_status.
    423 ///
    424 /// assert(status_known(A) || status_known(B));
    425 ///
    426 /// @returns True if A and B both represent the same file system entity, false
    427 ///          otherwise.
    428 bool equivalent(file_status A, file_status B);
    429 
    430 /// @brief Do paths represent the same thing?
    431 ///
    432 /// assert(status_known(A) || status_known(B));
    433 ///
    434 /// @param A Input path A.
    435 /// @param B Input path B.
    436 /// @param result Set to true if stat(A) and stat(B) have the same device and
    437 ///               inode (or equivalent).
    438 /// @returns errc::success if result has been successfully set, otherwise a
    439 ///          platform-specific error_code.
    440 std::error_code equivalent(const Twine &A, const Twine &B, bool &result);
    441 
    442 /// @brief Simpler version of equivalent for clients that don't need to
    443 ///        differentiate between an error and false.
    444 inline bool equivalent(const Twine &A, const Twine &B) {
    445   bool result;
    446   return !equivalent(A, B, result) && result;
    447 }
    448 
    449 /// @brief Does status represent a directory?
    450 ///
    451 /// @param status A file_status previously returned from status.
    452 /// @returns status.type() == file_type::directory_file.
    453 bool is_directory(file_status status);
    454 
    455 /// @brief Is path a directory?
    456 ///
    457 /// @param path Input path.
    458 /// @param result Set to true if \a path is a directory, false if it is not.
    459 ///               Undefined otherwise.
    460 /// @returns errc::success if result has been successfully set, otherwise a
    461 ///          platform-specific error_code.
    462 std::error_code is_directory(const Twine &path, bool &result);
    463 
    464 /// @brief Simpler version of is_directory for clients that don't need to
    465 ///        differentiate between an error and false.
    466 inline bool is_directory(const Twine &Path) {
    467   bool Result;
    468   return !is_directory(Path, Result) && Result;
    469 }
    470 
    471 /// @brief Does status represent a regular file?
    472 ///
    473 /// @param status A file_status previously returned from status.
    474 /// @returns status_known(status) && status.type() == file_type::regular_file.
    475 bool is_regular_file(file_status status);
    476 
    477 /// @brief Is path a regular file?
    478 ///
    479 /// @param path Input path.
    480 /// @param result Set to true if \a path is a regular file, false if it is not.
    481 ///               Undefined otherwise.
    482 /// @returns errc::success if result has been successfully set, otherwise a
    483 ///          platform-specific error_code.
    484 std::error_code is_regular_file(const Twine &path, bool &result);
    485 
    486 /// @brief Simpler version of is_regular_file for clients that don't need to
    487 ///        differentiate between an error and false.
    488 inline bool is_regular_file(const Twine &Path) {
    489   bool Result;
    490   if (is_regular_file(Path, Result))
    491     return false;
    492   return Result;
    493 }
    494 
    495 /// @brief Does this status represent something that exists but is not a
    496 ///        directory, regular file, or symlink?
    497 ///
    498 /// @param status A file_status previously returned from status.
    499 /// @returns exists(s) && !is_regular_file(s) && !is_directory(s)
    500 bool is_other(file_status status);
    501 
    502 /// @brief Is path something that exists but is not a directory,
    503 ///        regular file, or symlink?
    504 ///
    505 /// @param path Input path.
    506 /// @param result Set to true if \a path exists, but is not a directory, regular
    507 ///               file, or a symlink, false if it does not. Undefined otherwise.
    508 /// @returns errc::success if result has been successfully set, otherwise a
    509 ///          platform-specific error_code.
    510 std::error_code is_other(const Twine &path, bool &result);
    511 
    512 /// @brief Get file status as if by POSIX stat().
    513 ///
    514 /// @param path Input path.
    515 /// @param result Set to the file status.
    516 /// @returns errc::success if result has been successfully set, otherwise a
    517 ///          platform-specific error_code.
    518 std::error_code status(const Twine &path, file_status &result);
    519 
    520 /// @brief A version for when a file descriptor is already available.
    521 std::error_code status(int FD, file_status &Result);
    522 
    523 /// @brief Get file size.
    524 ///
    525 /// @param Path Input path.
    526 /// @param Result Set to the size of the file in \a Path.
    527 /// @returns errc::success if result has been successfully set, otherwise a
    528 ///          platform-specific error_code.
    529 inline std::error_code file_size(const Twine &Path, uint64_t &Result) {
    530   file_status Status;
    531   std::error_code EC = status(Path, Status);
    532   if (EC)
    533     return EC;
    534   Result = Status.getSize();
    535   return std::error_code();
    536 }
    537 
    538 /// @brief Set the file modification and access time.
    539 ///
    540 /// @returns errc::success if the file times were successfully set, otherwise a
    541 ///          platform-specific error_code or errc::function_not_supported on
    542 ///          platforms where the functionality isn't available.
    543 std::error_code setLastModificationAndAccessTime(int FD, TimeValue Time);
    544 
    545 /// @brief Is status available?
    546 ///
    547 /// @param s Input file status.
    548 /// @returns True if status() != status_error.
    549 bool status_known(file_status s);
    550 
    551 /// @brief Is status available?
    552 ///
    553 /// @param path Input path.
    554 /// @param result Set to true if status() != status_error.
    555 /// @returns errc::success if result has been successfully set, otherwise a
    556 ///          platform-specific error_code.
    557 std::error_code status_known(const Twine &path, bool &result);
    558 
    559 /// @brief Create a uniquely named file.
    560 ///
    561 /// Generates a unique path suitable for a temporary file and then opens it as a
    562 /// file. The name is based on \a model with '%' replaced by a random char in
    563 /// [0-9a-f]. If \a model is not an absolute path, the temporary file will be
    564 /// created in the current directory.
    565 ///
    566 /// Example: clang-%%-%%-%%-%%-%%.s => clang-a0-b1-c2-d3-e4.s
    567 ///
    568 /// This is an atomic operation. Either the file is created and opened, or the
    569 /// file system is left untouched.
    570 ///
    571 /// The intended use is for files that are to be kept, possibly after
    572 /// renaming them. For example, when running 'clang -c foo.o', the file can
    573 /// be first created as foo-abc123.o and then renamed.
    574 ///
    575 /// @param Model Name to base unique path off of.
    576 /// @param ResultFD Set to the opened file's file descriptor.
    577 /// @param ResultPath Set to the opened file's absolute path.
    578 /// @returns errc::success if Result{FD,Path} have been successfully set,
    579 ///          otherwise a platform-specific error_code.
    580 std::error_code createUniqueFile(const Twine &Model, int &ResultFD,
    581                                  SmallVectorImpl<char> &ResultPath,
    582                                  unsigned Mode = all_read | all_write);
    583 
    584 /// @brief Simpler version for clients that don't want an open file.
    585 std::error_code createUniqueFile(const Twine &Model,
    586                                  SmallVectorImpl<char> &ResultPath);
    587 
    588 /// @brief Create a file in the system temporary directory.
    589 ///
    590 /// The filename is of the form prefix-random_chars.suffix. Since the directory
    591 /// is not know to the caller, Prefix and Suffix cannot have path separators.
    592 /// The files are created with mode 0600.
    593 ///
    594 /// This should be used for things like a temporary .s that is removed after
    595 /// running the assembler.
    596 std::error_code createTemporaryFile(const Twine &Prefix, StringRef Suffix,
    597                                     int &ResultFD,
    598                                     SmallVectorImpl<char> &ResultPath);
    599 
    600 /// @brief Simpler version for clients that don't want an open file.
    601 std::error_code createTemporaryFile(const Twine &Prefix, StringRef Suffix,
    602                                     SmallVectorImpl<char> &ResultPath);
    603 
    604 std::error_code createUniqueDirectory(const Twine &Prefix,
    605                                       SmallVectorImpl<char> &ResultPath);
    606 
    607 /// @brief Fetch a path to an open file, as specified by a file descriptor
    608 ///
    609 /// @param FD File descriptor to a currently open file
    610 /// @param ResultPath The buffer into which to write the path
    611 std::error_code getPathFromOpenFD(int FD, SmallVectorImpl<char> &ResultPath);
    612 
    613 enum OpenFlags : unsigned {
    614   F_None = 0,
    615 
    616   /// F_Excl - When opening a file, this flag makes raw_fd_ostream
    617   /// report an error if the file already exists.
    618   F_Excl = 1,
    619 
    620   /// F_Append - When opening a file, if it already exists append to the
    621   /// existing file instead of returning an error.  This may not be specified
    622   /// with F_Excl.
    623   F_Append = 2,
    624 
    625   /// The file should be opened in text mode on platforms that make this
    626   /// distinction.
    627   F_Text = 4,
    628 
    629   /// Open the file for read and write.
    630   F_RW = 8
    631 };
    632 
    633 inline OpenFlags operator|(OpenFlags A, OpenFlags B) {
    634   return OpenFlags(unsigned(A) | unsigned(B));
    635 }
    636 
    637 inline OpenFlags &operator|=(OpenFlags &A, OpenFlags B) {
    638   A = A | B;
    639   return A;
    640 }
    641 
    642 std::error_code openFileForWrite(const Twine &Name, int &ResultFD,
    643                                  OpenFlags Flags, unsigned Mode = 0666);
    644 
    645 std::error_code openFileForRead(const Twine &Name, int &ResultFD,
    646                                 SmallVectorImpl<char> *RealPath = nullptr);
    647 
    648 /// @brief Identify the type of a binary file based on how magical it is.
    649 file_magic identify_magic(StringRef magic);
    650 
    651 /// @brief Get and identify \a path's type based on its content.
    652 ///
    653 /// @param path Input path.
    654 /// @param result Set to the type of file, or file_magic::unknown.
    655 /// @returns errc::success if result has been successfully set, otherwise a
    656 ///          platform-specific error_code.
    657 std::error_code identify_magic(const Twine &path, file_magic &result);
    658 
    659 std::error_code getUniqueID(const Twine Path, UniqueID &Result);
    660 
    661 /// @brief Get disk space usage information.
    662 ///
    663 /// Note: Users must be careful about "Time Of Check, Time Of Use" kind of bug.
    664 /// Note: Windows reports results according to the quota allocated to the user.
    665 ///
    666 /// @param Path Input path.
    667 /// @returns a space_info structure filled with the capacity, free, and
    668 /// available space on the device \a Path is on. A platform specific error_code
    669 /// is returned on error.
    670 ErrorOr<space_info> disk_space(const Twine &Path);
    671 
    672 /// This class represents a memory mapped file. It is based on
    673 /// boost::iostreams::mapped_file.
    674 class mapped_file_region {
    675   mapped_file_region() = delete;
    676   mapped_file_region(mapped_file_region&) = delete;
    677   mapped_file_region &operator =(mapped_file_region&) = delete;
    678 
    679 public:
    680   enum mapmode {
    681     readonly, ///< May only access map via const_data as read only.
    682     readwrite, ///< May access map via data and modify it. Written to path.
    683     priv ///< May modify via data, but changes are lost on destruction.
    684   };
    685 
    686 private:
    687   /// Platform-specific mapping state.
    688   uint64_t Size;
    689   void *Mapping;
    690 
    691   std::error_code init(int FD, uint64_t Offset, mapmode Mode);
    692 
    693 public:
    694   /// \param fd An open file descriptor to map. mapped_file_region takes
    695   ///   ownership if closefd is true. It must have been opended in the correct
    696   ///   mode.
    697   mapped_file_region(int fd, mapmode mode, uint64_t length, uint64_t offset,
    698                      std::error_code &ec);
    699 
    700   ~mapped_file_region();
    701 
    702   uint64_t size() const;
    703   char *data() const;
    704 
    705   /// Get a const view of the data. Modifying this memory has undefined
    706   /// behavior.
    707   const char *const_data() const;
    708 
    709   /// \returns The minimum alignment offset must be.
    710   static int alignment();
    711 };
    712 
    713 /// Return the path to the main executable, given the value of argv[0] from
    714 /// program startup and the address of main itself. In extremis, this function
    715 /// may fail and return an empty path.
    716 std::string getMainExecutable(const char *argv0, void *MainExecAddr);
    717 
    718 /// @}
    719 /// @name Iterators
    720 /// @{
    721 
    722 /// directory_entry - A single entry in a directory. Caches the status either
    723 /// from the result of the iteration syscall, or the first time status is
    724 /// called.
    725 class directory_entry {
    726   std::string Path;
    727   mutable file_status Status;
    728 
    729 public:
    730   explicit directory_entry(const Twine &path, file_status st = file_status())
    731     : Path(path.str())
    732     , Status(st) {}
    733 
    734   directory_entry() {}
    735 
    736   void assign(const Twine &path, file_status st = file_status()) {
    737     Path = path.str();
    738     Status = st;
    739   }
    740 
    741   void replace_filename(const Twine &filename, file_status st = file_status());
    742 
    743   const std::string &path() const { return Path; }
    744   std::error_code status(file_status &result) const;
    745 
    746   bool operator==(const directory_entry& rhs) const { return Path == rhs.Path; }
    747   bool operator!=(const directory_entry& rhs) const { return !(*this == rhs); }
    748   bool operator< (const directory_entry& rhs) const;
    749   bool operator<=(const directory_entry& rhs) const;
    750   bool operator> (const directory_entry& rhs) const;
    751   bool operator>=(const directory_entry& rhs) const;
    752 };
    753 
    754 namespace detail {
    755   struct DirIterState;
    756 
    757   std::error_code directory_iterator_construct(DirIterState &, StringRef);
    758   std::error_code directory_iterator_increment(DirIterState &);
    759   std::error_code directory_iterator_destruct(DirIterState &);
    760 
    761   /// DirIterState - Keeps state for the directory_iterator. It is reference
    762   /// counted in order to preserve InputIterator semantics on copy.
    763   struct DirIterState : public RefCountedBase<DirIterState> {
    764     DirIterState()
    765       : IterationHandle(0) {}
    766 
    767     ~DirIterState() {
    768       directory_iterator_destruct(*this);
    769     }
    770 
    771     intptr_t IterationHandle;
    772     directory_entry CurrentEntry;
    773   };
    774 } // end namespace detail
    775 
    776 /// directory_iterator - Iterates through the entries in path. There is no
    777 /// operator++ because we need an error_code. If it's really needed we can make
    778 /// it call report_fatal_error on error.
    779 class directory_iterator {
    780   IntrusiveRefCntPtr<detail::DirIterState> State;
    781 
    782 public:
    783   explicit directory_iterator(const Twine &path, std::error_code &ec) {
    784     State = new detail::DirIterState;
    785     SmallString<128> path_storage;
    786     ec = detail::directory_iterator_construct(*State,
    787             path.toStringRef(path_storage));
    788   }
    789 
    790   explicit directory_iterator(const directory_entry &de, std::error_code &ec) {
    791     State = new detail::DirIterState;
    792     ec = detail::directory_iterator_construct(*State, de.path());
    793   }
    794 
    795   /// Construct end iterator.
    796   directory_iterator() : State(nullptr) {}
    797 
    798   // No operator++ because we need error_code.
    799   directory_iterator &increment(std::error_code &ec) {
    800     ec = directory_iterator_increment(*State);
    801     return *this;
    802   }
    803 
    804   const directory_entry &operator*() const { return State->CurrentEntry; }
    805   const directory_entry *operator->() const { return &State->CurrentEntry; }
    806 
    807   bool operator==(const directory_iterator &RHS) const {
    808     if (State == RHS.State)
    809       return true;
    810     if (!RHS.State)
    811       return State->CurrentEntry == directory_entry();
    812     if (!State)
    813       return RHS.State->CurrentEntry == directory_entry();
    814     return State->CurrentEntry == RHS.State->CurrentEntry;
    815   }
    816 
    817   bool operator!=(const directory_iterator &RHS) const {
    818     return !(*this == RHS);
    819   }
    820   // Other members as required by
    821   // C++ Std, 24.1.1 Input iterators [input.iterators]
    822 };
    823 
    824 namespace detail {
    825   /// RecDirIterState - Keeps state for the recursive_directory_iterator. It is
    826   /// reference counted in order to preserve InputIterator semantics on copy.
    827   struct RecDirIterState : public RefCountedBase<RecDirIterState> {
    828     RecDirIterState()
    829       : Level(0)
    830       , HasNoPushRequest(false) {}
    831 
    832     std::stack<directory_iterator, std::vector<directory_iterator> > Stack;
    833     uint16_t Level;
    834     bool HasNoPushRequest;
    835   };
    836 } // end namespace detail
    837 
    838 /// recursive_directory_iterator - Same as directory_iterator except for it
    839 /// recurses down into child directories.
    840 class recursive_directory_iterator {
    841   IntrusiveRefCntPtr<detail::RecDirIterState> State;
    842 
    843 public:
    844   recursive_directory_iterator() {}
    845   explicit recursive_directory_iterator(const Twine &path, std::error_code &ec)
    846       : State(new detail::RecDirIterState) {
    847     State->Stack.push(directory_iterator(path, ec));
    848     if (State->Stack.top() == directory_iterator())
    849       State.reset();
    850   }
    851   // No operator++ because we need error_code.
    852   recursive_directory_iterator &increment(std::error_code &ec) {
    853     const directory_iterator end_itr;
    854 
    855     if (State->HasNoPushRequest)
    856       State->HasNoPushRequest = false;
    857     else {
    858       file_status st;
    859       if ((ec = State->Stack.top()->status(st))) return *this;
    860       if (is_directory(st)) {
    861         State->Stack.push(directory_iterator(*State->Stack.top(), ec));
    862         if (ec) return *this;
    863         if (State->Stack.top() != end_itr) {
    864           ++State->Level;
    865           return *this;
    866         }
    867         State->Stack.pop();
    868       }
    869     }
    870 
    871     while (!State->Stack.empty()
    872            && State->Stack.top().increment(ec) == end_itr) {
    873       State->Stack.pop();
    874       --State->Level;
    875     }
    876 
    877     // Check if we are done. If so, create an end iterator.
    878     if (State->Stack.empty())
    879       State.reset();
    880 
    881     return *this;
    882   }
    883 
    884   const directory_entry &operator*() const { return *State->Stack.top(); }
    885   const directory_entry *operator->() const { return &*State->Stack.top(); }
    886 
    887   // observers
    888   /// Gets the current level. Starting path is at level 0.
    889   int level() const { return State->Level; }
    890 
    891   /// Returns true if no_push has been called for this directory_entry.
    892   bool no_push_request() const { return State->HasNoPushRequest; }
    893 
    894   // modifiers
    895   /// Goes up one level if Level > 0.
    896   void pop() {
    897     assert(State && "Cannot pop an end iterator!");
    898     assert(State->Level > 0 && "Cannot pop an iterator with level < 1");
    899 
    900     const directory_iterator end_itr;
    901     std::error_code ec;
    902     do {
    903       if (ec)
    904         report_fatal_error("Error incrementing directory iterator.");
    905       State->Stack.pop();
    906       --State->Level;
    907     } while (!State->Stack.empty()
    908              && State->Stack.top().increment(ec) == end_itr);
    909 
    910     // Check if we are done. If so, create an end iterator.
    911     if (State->Stack.empty())
    912       State.reset();
    913   }
    914 
    915   /// Does not go down into the current directory_entry.
    916   void no_push() { State->HasNoPushRequest = true; }
    917 
    918   bool operator==(const recursive_directory_iterator &RHS) const {
    919     return State == RHS.State;
    920   }
    921 
    922   bool operator!=(const recursive_directory_iterator &RHS) const {
    923     return !(*this == RHS);
    924   }
    925   // Other members as required by
    926   // C++ Std, 24.1.1 Input iterators [input.iterators]
    927 };
    928 
    929 /// @}
    930 
    931 } // end namespace fs
    932 } // end namespace sys
    933 } // end namespace llvm
    934 
    935 #endif // LLVM_SUPPORT_FILESYSTEM_H
    936