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