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      1 //===- llvm/Support/PathV1.h - Path Operating System 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::Path class.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #ifndef LLVM_SYSTEM_PATH_H
     15 #define LLVM_SYSTEM_PATH_H
     16 
     17 #include "llvm/ADT/StringRef.h"
     18 #include "llvm/Support/Compiler.h"
     19 #include "llvm/Support/TimeValue.h"
     20 #include <set>
     21 #include <string>
     22 #include <vector>
     23 
     24 #define LLVM_PATH_DEPRECATED_MSG(replacement) \
     25   "PathV1 has been deprecated and will be removed as soon as all LLVM and" \
     26   " Clang clients have been moved over to PathV2. Please use `" #replacement \
     27   "` from PathV2 instead."
     28 
     29 namespace llvm {
     30 namespace sys {
     31 
     32   /// This structure provides basic file system information about a file. It
     33   /// is patterned after the stat(2) Unix operating system call but made
     34   /// platform independent and eliminates many of the unix-specific fields.
     35   /// However, to support llvm-ar, the mode, user, and group fields are
     36   /// retained. These pertain to unix security and may not have a meaningful
     37   /// value on non-Unix platforms. However, the other fields should
     38   /// always be applicable on all platforms.  The structure is filled in by
     39   /// the PathWithStatus class.
     40   /// @brief File status structure
     41   class FileStatus {
     42   public:
     43     uint64_t    fileSize;   ///< Size of the file in bytes
     44     TimeValue   modTime;    ///< Time of file's modification
     45     uint32_t    mode;       ///< Mode of the file, if applicable
     46     uint32_t    user;       ///< User ID of owner, if applicable
     47     uint32_t    group;      ///< Group ID of owner, if applicable
     48     uint64_t    uniqueID;   ///< A number to uniquely ID this file
     49     bool        isDir  : 1; ///< True if this is a directory.
     50     bool        isFile : 1; ///< True if this is a file.
     51 
     52     FileStatus() : fileSize(0), modTime(0,0), mode(0777), user(999),
     53                    group(999), uniqueID(0), isDir(false), isFile(false) { }
     54 
     55     TimeValue getTimestamp() const { return modTime; }
     56     uint64_t getSize() const { return fileSize; }
     57     uint32_t getMode() const { return mode; }
     58     uint32_t getUser() const { return user; }
     59     uint32_t getGroup() const { return group; }
     60     uint64_t getUniqueID() const { return uniqueID; }
     61   };
     62 
     63   /// This class provides an abstraction for the path to a file or directory
     64   /// in the operating system's filesystem and provides various basic operations
     65   /// on it.  Note that this class only represents the name of a path to a file
     66   /// or directory which may or may not be valid for a given machine's file
     67   /// system. The class is patterned after the java.io.File class with various
     68   /// extensions and several omissions (not relevant to LLVM).  A Path object
     69   /// ensures that the path it encapsulates is syntactically valid for the
     70   /// operating system it is running on but does not ensure correctness for
     71   /// any particular file system. That is, a syntactically valid path might
     72   /// specify path components that do not exist in the file system and using
     73   /// such a Path to act on the file system could produce errors. There is one
     74   /// invalid Path value which is permitted: the empty path.  The class should
     75   /// never allow a syntactically invalid non-empty path name to be assigned.
     76   /// Empty paths are required in order to indicate an error result in some
     77   /// situations. If the path is empty, the isValid operation will return
     78   /// false. All operations will fail if isValid is false. Operations that
     79   /// change the path will either return false if it would cause a syntactically
     80   /// invalid path name (in which case the Path object is left unchanged) or
     81   /// throw an std::string exception indicating the error. The methods are
     82   /// grouped into four basic categories: Path Accessors (provide information
     83   /// about the path without accessing disk), Disk Accessors (provide
     84   /// information about the underlying file or directory), Path Mutators
     85   /// (change the path information, not the disk), and Disk Mutators (change
     86   /// the disk file/directory referenced by the path). The Disk Mutator methods
     87   /// all have the word "disk" embedded in their method name to reinforce the
     88   /// notion that the operation modifies the file system.
     89   /// @since 1.4
     90   /// @brief An abstraction for operating system paths.
     91   class Path {
     92     /// @name Constructors
     93     /// @{
     94     public:
     95       /// Construct a path to the root directory of the file system. The root
     96       /// directory is a top level directory above which there are no more
     97       /// directories. For example, on UNIX, the root directory is /. On Windows
     98       /// it is file:///. Other operating systems may have different notions of
     99       /// what the root directory is or none at all. In that case, a consistent
    100       /// default root directory will be used.
    101       LLVM_ATTRIBUTE_DEPRECATED(static Path GetRootDirectory(),
    102         LLVM_PATH_DEPRECATED_MSG(NOTHING));
    103 
    104       /// Construct a path to a unique temporary directory that is created in
    105       /// a "standard" place for the operating system. The directory is
    106       /// guaranteed to be created on exit from this function. If the directory
    107       /// cannot be created, the function will throw an exception.
    108       /// @returns an invalid path (empty) on error
    109       /// @param ErrMsg Optional place for an error message if an error occurs
    110       /// @brief Construct a path to an new, unique, existing temporary
    111       /// directory.
    112       static Path GetTemporaryDirectory(std::string* ErrMsg = 0);
    113 
    114       /// Construct a vector of sys::Path that contains the "standard" system
    115       /// library paths suitable for linking into programs.
    116       /// @brief Construct a path to the system library directory
    117       static void GetSystemLibraryPaths(std::vector<sys::Path>& Paths);
    118 
    119       /// Construct a vector of sys::Path that contains the "standard" bitcode
    120       /// library paths suitable for linking into an llvm program. This function
    121       /// *must* return the value of LLVM_LIB_SEARCH_PATH as well as the value
    122       /// of LLVM_LIBDIR. It also must provide the System library paths as
    123       /// returned by GetSystemLibraryPaths.
    124       /// @see GetSystemLibraryPaths
    125       /// @brief Construct a list of directories in which bitcode could be
    126       /// found.
    127       static void GetBitcodeLibraryPaths(std::vector<sys::Path>& Paths);
    128 
    129       /// Find the path to a library using its short name. Use the system
    130       /// dependent library paths to locate the library.
    131       /// @brief Find a library.
    132       static Path FindLibrary(std::string& short_name);
    133 
    134       /// Construct a path to the default LLVM configuration directory. The
    135       /// implementation must ensure that this is a well-known (same on many
    136       /// systems) directory in which llvm configuration files exist. For
    137       /// example, on Unix, the /etc/llvm directory has been selected.
    138       /// @brief Construct a path to the default LLVM configuration directory
    139       static Path GetLLVMDefaultConfigDir();
    140 
    141       /// Construct a path to the LLVM installed configuration directory. The
    142       /// implementation must ensure that this refers to the "etc" directory of
    143       /// the LLVM installation. This is the location where configuration files
    144       /// will be located for a particular installation of LLVM on a machine.
    145       /// @brief Construct a path to the LLVM installed configuration directory
    146       static Path GetLLVMConfigDir();
    147 
    148       /// Construct a path to the current user's home directory. The
    149       /// implementation must use an operating system specific mechanism for
    150       /// determining the user's home directory. For example, the environment
    151       /// variable "HOME" could be used on Unix. If a given operating system
    152       /// does not have the concept of a user's home directory, this static
    153       /// constructor must provide the same result as GetRootDirectory.
    154       /// @brief Construct a path to the current user's "home" directory
    155       static Path GetUserHomeDirectory();
    156 
    157       /// Construct a path to the current directory for the current process.
    158       /// @returns The current working directory.
    159       /// @brief Returns the current working directory.
    160       static Path GetCurrentDirectory();
    161 
    162       /// Return the suffix commonly used on file names that contain an
    163       /// executable.
    164       /// @returns The executable file suffix for the current platform.
    165       /// @brief Return the executable file suffix.
    166       static StringRef GetEXESuffix();
    167 
    168       /// Return the suffix commonly used on file names that contain a shared
    169       /// object, shared archive, or dynamic link library. Such files are
    170       /// linked at runtime into a process and their code images are shared
    171       /// between processes.
    172       /// @returns The dynamic link library suffix for the current platform.
    173       /// @brief Return the dynamic link library suffix.
    174       static StringRef GetDLLSuffix();
    175 
    176       /// GetMainExecutable - Return the path to the main executable, given the
    177       /// value of argv[0] from program startup and the address of main itself.
    178       /// In extremis, this function may fail and return an empty path.
    179       static Path GetMainExecutable(const char *argv0, void *MainAddr);
    180 
    181       /// This is one of the very few ways in which a path can be constructed
    182       /// with a syntactically invalid name. The only *legal* invalid name is an
    183       /// empty one. Other invalid names are not permitted. Empty paths are
    184       /// provided so that they can be used to indicate null or error results in
    185       /// other lib/System functionality.
    186       /// @brief Construct an empty (and invalid) path.
    187       Path() : path() {}
    188       Path(const Path &that) : path(that.path) {}
    189 
    190       /// This constructor will accept a char* or std::string as a path. No
    191       /// checking is done on this path to determine if it is valid. To
    192       /// determine validity of the path, use the isValid method.
    193       /// @param p The path to assign.
    194       /// @brief Construct a Path from a string.
    195       explicit Path(StringRef p);
    196 
    197       /// This constructor will accept a character range as a path.  No checking
    198       /// is done on this path to determine if it is valid.  To determine
    199       /// validity of the path, use the isValid method.
    200       /// @param StrStart A pointer to the first character of the path name
    201       /// @param StrLen The length of the path name at StrStart
    202       /// @brief Construct a Path from a string.
    203       Path(const char *StrStart, unsigned StrLen);
    204 
    205     /// @}
    206     /// @name Operators
    207     /// @{
    208     public:
    209       /// Makes a copy of \p that to \p this.
    210       /// @returns \p this
    211       /// @brief Assignment Operator
    212       Path &operator=(const Path &that) {
    213         path = that.path;
    214         return *this;
    215       }
    216 
    217       /// Makes a copy of \p that to \p this.
    218       /// @param that A StringRef denoting the path
    219       /// @returns \p this
    220       /// @brief Assignment Operator
    221       Path &operator=(StringRef that);
    222 
    223       /// Compares \p this Path with \p that Path for equality.
    224       /// @returns true if \p this and \p that refer to the same thing.
    225       /// @brief Equality Operator
    226       bool operator==(const Path &that) const;
    227 
    228       /// Compares \p this Path with \p that Path for inequality.
    229       /// @returns true if \p this and \p that refer to different things.
    230       /// @brief Inequality Operator
    231       bool operator!=(const Path &that) const { return !(*this == that); }
    232 
    233       /// Determines if \p this Path is less than \p that Path. This is required
    234       /// so that Path objects can be placed into ordered collections (e.g.
    235       /// std::map). The comparison is done lexicographically as defined by
    236       /// the std::string::compare method.
    237       /// @returns true if \p this path is lexicographically less than \p that.
    238       /// @brief Less Than Operator
    239       bool operator<(const Path& that) const;
    240 
    241     /// @}
    242     /// @name Path Accessors
    243     /// @{
    244     public:
    245       /// This function will use an operating system specific algorithm to
    246       /// determine if the current value of \p this is a syntactically valid
    247       /// path name for the operating system. The path name does not need to
    248       /// exist, validity is simply syntactical. Empty paths are always invalid.
    249       /// @returns true iff the path name is syntactically legal for the
    250       /// host operating system.
    251       /// @brief Determine if a path is syntactically valid or not.
    252       bool isValid() const;
    253 
    254       /// This function determines if the contents of the path name are empty.
    255       /// That is, the path name has a zero length. This does NOT determine if
    256       /// if the file is empty. To get the length of the file itself, Use the
    257       /// PathWithStatus::getFileStatus() method and then the getSize() method
    258       /// on the returned FileStatus object.
    259       /// @returns true iff the path is empty.
    260       /// @brief Determines if the path name is empty (invalid).
    261       bool isEmpty() const { return path.empty(); }
    262 
    263        /// This function returns the last component of the path name. The last
    264       /// component is the file or directory name occurring after the last
    265       /// directory separator. If no directory separator is present, the entire
    266       /// path name is returned (i.e. same as toString).
    267       /// @returns StringRef containing the last component of the path name.
    268       /// @brief Returns the last component of the path name.
    269       LLVM_ATTRIBUTE_DEPRECATED(
    270         StringRef getLast() const,
    271         LLVM_PATH_DEPRECATED_MSG(path::filename));
    272 
    273       /// This function strips off the path and suffix of the file or directory
    274       /// name and returns just the basename. For example /a/foo.bar would cause
    275       /// this function to return "foo".
    276       /// @returns StringRef containing the basename of the path
    277       /// @brief Get the base name of the path
    278       LLVM_ATTRIBUTE_DEPRECATED(StringRef getBasename() const,
    279         LLVM_PATH_DEPRECATED_MSG(path::stem));
    280 
    281       /// This function strips off the suffix of the path beginning with the
    282       /// path separator ('/' on Unix, '\' on Windows) and returns the result.
    283       LLVM_ATTRIBUTE_DEPRECATED(StringRef getDirname() const,
    284         LLVM_PATH_DEPRECATED_MSG(path::parent_path));
    285 
    286       /// This function strips off the path and basename(up to and
    287       /// including the last dot) of the file or directory name and
    288       /// returns just the suffix. For example /a/foo.bar would cause
    289       /// this function to return "bar".
    290       /// @returns StringRef containing the suffix of the path
    291       /// @brief Get the suffix of the path
    292       LLVM_ATTRIBUTE_DEPRECATED(StringRef getSuffix() const,
    293         LLVM_PATH_DEPRECATED_MSG(path::extension));
    294 
    295       /// Obtain a 'C' string for the path name.
    296       /// @returns a 'C' string containing the path name.
    297       /// @brief Returns the path as a C string.
    298       const char *c_str() const { return path.c_str(); }
    299       const std::string &str() const { return path; }
    300 
    301 
    302       /// size - Return the length in bytes of this path name.
    303       size_t size() const { return path.size(); }
    304 
    305       /// empty - Returns true if the path is empty.
    306       unsigned empty() const { return path.empty(); }
    307 
    308     /// @}
    309     /// @name Disk Accessors
    310     /// @{
    311     public:
    312       /// This function determines if the path name is absolute, as opposed to
    313       /// relative.
    314       /// @brief Determine if the path is absolute.
    315       LLVM_ATTRIBUTE_DEPRECATED(
    316         bool isAbsolute() const,
    317         LLVM_PATH_DEPRECATED_MSG(path::is_absolute));
    318 
    319       /// This function determines if the path name is absolute, as opposed to
    320       /// relative.
    321       /// @brief Determine if the path is absolute.
    322       LLVM_ATTRIBUTE_DEPRECATED(
    323         static bool isAbsolute(const char *NameStart, unsigned NameLen),
    324         LLVM_PATH_DEPRECATED_MSG(path::is_absolute));
    325 
    326       /// This function opens the file associated with the path name provided by
    327       /// the Path object and reads its magic number. If the magic number at the
    328       /// start of the file matches \p magic, true is returned. In all other
    329       /// cases (file not found, file not accessible, etc.) it returns false.
    330       /// @returns true if the magic number of the file matches \p magic.
    331       /// @brief Determine if file has a specific magic number
    332       LLVM_ATTRIBUTE_DEPRECATED(bool hasMagicNumber(StringRef magic) const,
    333         LLVM_PATH_DEPRECATED_MSG(fs::has_magic));
    334 
    335       /// This function retrieves the first \p len bytes of the file associated
    336       /// with \p this. These bytes are returned as the "magic number" in the
    337       /// \p Magic parameter.
    338       /// @returns true if the Path is a file and the magic number is retrieved,
    339       /// false otherwise.
    340       /// @brief Get the file's magic number.
    341       bool getMagicNumber(std::string& Magic, unsigned len) const;
    342 
    343       /// This function determines if the path name in the object references an
    344       /// archive file by looking at its magic number.
    345       /// @returns true if the file starts with the magic number for an archive
    346       /// file.
    347       /// @brief Determine if the path references an archive file.
    348       bool isArchive() const;
    349 
    350       /// This function determines if the path name in the object references an
    351       /// LLVM Bitcode file by looking at its magic number.
    352       /// @returns true if the file starts with the magic number for LLVM
    353       /// bitcode files.
    354       /// @brief Determine if the path references a bitcode file.
    355       bool isBitcodeFile() const;
    356 
    357       /// This function determines if the path name in the object references a
    358       /// native Dynamic Library (shared library, shared object) by looking at
    359       /// the file's magic number. The Path object must reference a file, not a
    360       /// directory.
    361       /// @returns true if the file starts with the magic number for a native
    362       /// shared library.
    363       /// @brief Determine if the path references a dynamic library.
    364       bool isDynamicLibrary() const;
    365 
    366       /// This function determines if the path name in the object references a
    367       /// native object file by looking at it's magic number. The term object
    368       /// file is defined as "an organized collection of separate, named
    369       /// sequences of binary data." This covers the obvious file formats such
    370       /// as COFF and ELF, but it also includes llvm ir bitcode, archives,
    371       /// libraries, etc...
    372       /// @returns true if the file starts with the magic number for an object
    373       /// file.
    374       /// @brief Determine if the path references an object file.
    375       bool isObjectFile() const;
    376 
    377       /// This function determines if the path name references an existing file
    378       /// or directory in the file system.
    379       /// @returns true if the pathname references an existing file or
    380       /// directory.
    381       /// @brief Determines if the path is a file or directory in
    382       /// the file system.
    383       LLVM_ATTRIBUTE_DEPRECATED(bool exists() const,
    384         LLVM_PATH_DEPRECATED_MSG(fs::exists));
    385 
    386       /// This function determines if the path name references an
    387       /// existing directory.
    388       /// @returns true if the pathname references an existing directory.
    389       /// @brief Determines if the path is a directory in the file system.
    390       LLVM_ATTRIBUTE_DEPRECATED(bool isDirectory() const,
    391         LLVM_PATH_DEPRECATED_MSG(fs::is_directory));
    392 
    393       /// This function determines if the path name references an
    394       /// existing symbolic link.
    395       /// @returns true if the pathname references an existing symlink.
    396       /// @brief Determines if the path is a symlink in the file system.
    397       LLVM_ATTRIBUTE_DEPRECATED(bool isSymLink() const,
    398         LLVM_PATH_DEPRECATED_MSG(fs::is_symlink));
    399 
    400       /// This function determines if the path name references a readable file
    401       /// or directory in the file system. This function checks for
    402       /// the existence and readability (by the current program) of the file
    403       /// or directory.
    404       /// @returns true if the pathname references a readable file.
    405       /// @brief Determines if the path is a readable file or directory
    406       /// in the file system.
    407       bool canRead() const;
    408 
    409       /// This function determines if the path name references a writable file
    410       /// or directory in the file system. This function checks for the
    411       /// existence and writability (by the current program) of the file or
    412       /// directory.
    413       /// @returns true if the pathname references a writable file.
    414       /// @brief Determines if the path is a writable file or directory
    415       /// in the file system.
    416       bool canWrite() const;
    417 
    418       /// This function checks that what we're trying to work only on a regular
    419       /// file. Check for things like /dev/null, any block special file, or
    420       /// other things that aren't "regular" regular files.
    421       /// @returns true if the file is S_ISREG.
    422       /// @brief Determines if the file is a regular file
    423       bool isRegularFile() const;
    424 
    425       /// This function determines if the path name references an executable
    426       /// file in the file system. This function checks for the existence and
    427       /// executability (by the current program) of the file.
    428       /// @returns true if the pathname references an executable file.
    429       /// @brief Determines if the path is an executable file in the file
    430       /// system.
    431       bool canExecute() const;
    432 
    433       /// This function builds a list of paths that are the names of the
    434       /// files and directories in a directory.
    435       /// @returns true if an error occurs, true otherwise
    436       /// @brief Build a list of directory's contents.
    437       bool getDirectoryContents(
    438         std::set<Path> &paths, ///< The resulting list of file & directory names
    439         std::string* ErrMsg    ///< Optional place to return an error message.
    440       ) const;
    441 
    442     /// @}
    443     /// @name Path Mutators
    444     /// @{
    445     public:
    446       /// The path name is cleared and becomes empty. This is an invalid
    447       /// path name but is the *only* invalid path name. This is provided
    448       /// so that path objects can be used to indicate the lack of a
    449       /// valid path being found.
    450       /// @brief Make the path empty.
    451       void clear() { path.clear(); }
    452 
    453       /// This method sets the Path object to \p unverified_path. This can fail
    454       /// if the \p unverified_path does not pass the syntactic checks of the
    455       /// isValid() method. If verification fails, the Path object remains
    456       /// unchanged and false is returned. Otherwise true is returned and the
    457       /// Path object takes on the path value of \p unverified_path
    458       /// @returns true if the path was set, false otherwise.
    459       /// @param unverified_path The path to be set in Path object.
    460       /// @brief Set a full path from a StringRef
    461       bool set(StringRef unverified_path);
    462 
    463       /// One path component is removed from the Path. If only one component is
    464       /// present in the path, the Path object becomes empty. If the Path object
    465       /// is empty, no change is made.
    466       /// @returns false if the path component could not be removed.
    467       /// @brief Removes the last directory component of the Path.
    468       bool eraseComponent();
    469 
    470       /// The \p component is added to the end of the Path if it is a legal
    471       /// name for the operating system. A directory separator will be added if
    472       /// needed.
    473       /// @returns false if the path component could not be added.
    474       /// @brief Appends one path component to the Path.
    475       bool appendComponent(StringRef component);
    476 
    477       /// A period and the \p suffix are appended to the end of the pathname.
    478       /// When the \p suffix is empty, no action is performed.
    479       /// @brief Adds a period and the \p suffix to the end of the pathname.
    480       void appendSuffix(StringRef suffix);
    481 
    482       /// The suffix of the filename is erased. The suffix begins with and
    483       /// includes the last . character in the filename after the last directory
    484       /// separator and extends until the end of the name. If no . character is
    485       /// after the last directory separator, then the file name is left
    486       /// unchanged (i.e. it was already without a suffix) but the function
    487       /// returns false.
    488       /// @returns false if there was no suffix to remove, true otherwise.
    489       /// @brief Remove the suffix from a path name.
    490       bool eraseSuffix();
    491 
    492       /// The current Path name is made unique in the file system. Upon return,
    493       /// the Path will have been changed to make a unique file in the file
    494       /// system or it will not have been changed if the current path name is
    495       /// already unique.
    496       /// @throws std::string if an unrecoverable error occurs.
    497       /// @brief Make the current path name unique in the file system.
    498       bool makeUnique( bool reuse_current /*= true*/, std::string* ErrMsg );
    499 
    500       /// The current Path name is made absolute by prepending the
    501       /// current working directory if necessary.
    502       LLVM_ATTRIBUTE_DEPRECATED(
    503         void makeAbsolute(),
    504         LLVM_PATH_DEPRECATED_MSG(fs::make_absolute));
    505 
    506     /// @}
    507     /// @name Disk Mutators
    508     /// @{
    509     public:
    510       /// This method attempts to make the file referenced by the Path object
    511       /// available for reading so that the canRead() method will return true.
    512       /// @brief Make the file readable;
    513       bool makeReadableOnDisk(std::string* ErrMsg = 0);
    514 
    515       /// This method attempts to make the file referenced by the Path object
    516       /// available for writing so that the canWrite() method will return true.
    517       /// @brief Make the file writable;
    518       bool makeWriteableOnDisk(std::string* ErrMsg = 0);
    519 
    520       /// This method attempts to make the file referenced by the Path object
    521       /// available for execution so that the canExecute() method will return
    522       /// true.
    523       /// @brief Make the file readable;
    524       bool makeExecutableOnDisk(std::string* ErrMsg = 0);
    525 
    526       /// This method allows the last modified time stamp and permission bits
    527       /// to be set on the disk object referenced by the Path.
    528       /// @throws std::string if an error occurs.
    529       /// @returns true on error.
    530       /// @brief Set the status information.
    531       bool setStatusInfoOnDisk(const FileStatus &SI,
    532                                std::string *ErrStr = 0) const;
    533 
    534       /// This method attempts to create a directory in the file system with the
    535       /// same name as the Path object. The \p create_parents parameter controls
    536       /// whether intermediate directories are created or not. if \p
    537       /// create_parents is true, then an attempt will be made to create all
    538       /// intermediate directories, as needed. If \p create_parents is false,
    539       /// then only the final directory component of the Path name will be
    540       /// created. The created directory will have no entries.
    541       /// @returns true if the directory could not be created, false otherwise
    542       /// @brief Create the directory this Path refers to.
    543       bool createDirectoryOnDisk(
    544         bool create_parents = false, ///<  Determines whether non-existent
    545            ///< directory components other than the last one (the "parents")
    546            ///< are created or not.
    547         std::string* ErrMsg = 0 ///< Optional place to put error messages.
    548       );
    549 
    550       /// This method attempts to create a file in the file system with the same
    551       /// name as the Path object. The intermediate directories must all exist
    552       /// at the time this method is called. Use createDirectoriesOnDisk to
    553       /// accomplish that. The created file will be empty upon return from this
    554       /// function.
    555       /// @returns true if the file could not be created, false otherwise.
    556       /// @brief Create the file this Path refers to.
    557       bool createFileOnDisk(
    558         std::string* ErrMsg = 0 ///< Optional place to put error messages.
    559       );
    560 
    561       /// This is like createFile except that it creates a temporary file. A
    562       /// unique temporary file name is generated based on the contents of
    563       /// \p this before the call. The new name is assigned to \p this and the
    564       /// file is created.  Note that this will both change the Path object
    565       /// *and* create the corresponding file. This function will ensure that
    566       /// the newly generated temporary file name is unique in the file system.
    567       /// @returns true if the file couldn't be created, false otherwise.
    568       /// @brief Create a unique temporary file
    569       bool createTemporaryFileOnDisk(
    570         bool reuse_current = false, ///< When set to true, this parameter
    571           ///< indicates that if the current file name does not exist then
    572           ///< it will be used without modification.
    573         std::string* ErrMsg = 0 ///< Optional place to put error messages
    574       );
    575 
    576       /// This method renames the file referenced by \p this as \p newName. The
    577       /// file referenced by \p this must exist. The file referenced by
    578       /// \p newName does not need to exist.
    579       /// @returns true on error, false otherwise
    580       /// @brief Rename one file as another.
    581       bool renamePathOnDisk(const Path& newName, std::string* ErrMsg);
    582 
    583       /// This method attempts to destroy the file or directory named by the
    584       /// last component of the Path. If the Path refers to a directory and the
    585       /// \p destroy_contents is false, an attempt will be made to remove just
    586       /// the directory (the final Path component). If \p destroy_contents is
    587       /// true, an attempt will be made to remove the entire contents of the
    588       /// directory, recursively. If the Path refers to a file, the
    589       /// \p destroy_contents parameter is ignored.
    590       /// @param destroy_contents Indicates whether the contents of a destroyed
    591       /// @param Err An optional string to receive an error message.
    592       /// directory should also be destroyed (recursively).
    593       /// @returns false if the file/directory was destroyed, true on error.
    594       /// @brief Removes the file or directory from the filesystem.
    595       bool eraseFromDisk(bool destroy_contents = false,
    596                          std::string *Err = 0) const;
    597 
    598 
    599       /// MapInFilePages - This is a low level system API to map in the file
    600       /// that is currently opened as FD into the current processes' address
    601       /// space for read only access.  This function may return null on failure
    602       /// or if the system cannot provide the following constraints:
    603       ///  1) The pages must be valid after the FD is closed, until
    604       ///     UnMapFilePages is called.
    605       ///  2) Any padding after the end of the file must be zero filled, if
    606       ///     present.
    607       ///  3) The pages must be contiguous.
    608       ///
    609       /// This API is not intended for general use, clients should use
    610       /// MemoryBuffer::getFile instead.
    611       static const char *MapInFilePages(int FD, size_t FileSize,
    612                                         off_t Offset);
    613 
    614       /// UnMapFilePages - Free pages mapped into the current process by
    615       /// MapInFilePages.
    616       ///
    617       /// This API is not intended for general use, clients should use
    618       /// MemoryBuffer::getFile instead.
    619       static void UnMapFilePages(const char *Base, size_t FileSize);
    620 
    621     /// @}
    622     /// @name Data
    623     /// @{
    624     protected:
    625       // Our win32 implementation relies on this string being mutable.
    626       mutable std::string path;   ///< Storage for the path name.
    627 
    628 
    629     /// @}
    630   };
    631 
    632   /// This class is identical to Path class except it allows you to obtain the
    633   /// file status of the Path as well. The reason for the distinction is one of
    634   /// efficiency. First, the file status requires additional space and the space
    635   /// is incorporated directly into PathWithStatus without an additional malloc.
    636   /// Second, obtaining status information is an expensive operation on most
    637   /// operating systems so we want to be careful and explicit about where we
    638   /// allow this operation in LLVM.
    639   /// @brief Path with file status class.
    640   class PathWithStatus : public Path {
    641     /// @name Constructors
    642     /// @{
    643     public:
    644       /// @brief Default constructor
    645       PathWithStatus() : Path(), status(), fsIsValid(false) {}
    646 
    647       /// @brief Copy constructor
    648       PathWithStatus(const PathWithStatus &that)
    649         : Path(static_cast<const Path&>(that)), status(that.status),
    650            fsIsValid(that.fsIsValid) {}
    651 
    652       /// This constructor allows construction from a Path object
    653       /// @brief Path constructor
    654       PathWithStatus(const Path &other)
    655         : Path(other), status(), fsIsValid(false) {}
    656 
    657       /// This constructor will accept a char* or std::string as a path. No
    658       /// checking is done on this path to determine if it is valid. To
    659       /// determine validity of the path, use the isValid method.
    660       /// @brief Construct a Path from a string.
    661       explicit PathWithStatus(
    662         StringRef p ///< The path to assign.
    663       ) : Path(p), status(), fsIsValid(false) {}
    664 
    665       /// This constructor will accept a character range as a path.  No checking
    666       /// is done on this path to determine if it is valid.  To determine
    667       /// validity of the path, use the isValid method.
    668       /// @brief Construct a Path from a string.
    669       explicit PathWithStatus(
    670         const char *StrStart,  ///< Pointer to the first character of the path
    671         unsigned StrLen        ///< Length of the path.
    672       ) : Path(StrStart, StrLen), status(), fsIsValid(false) {}
    673 
    674       /// Makes a copy of \p that to \p this.
    675       /// @returns \p this
    676       /// @brief Assignment Operator
    677       PathWithStatus &operator=(const PathWithStatus &that) {
    678         static_cast<Path&>(*this) = static_cast<const Path&>(that);
    679         status = that.status;
    680         fsIsValid = that.fsIsValid;
    681         return *this;
    682       }
    683 
    684       /// Makes a copy of \p that to \p this.
    685       /// @returns \p this
    686       /// @brief Assignment Operator
    687       PathWithStatus &operator=(const Path &that) {
    688         static_cast<Path&>(*this) = static_cast<const Path&>(that);
    689         fsIsValid = false;
    690         return *this;
    691       }
    692 
    693     /// @}
    694     /// @name Methods
    695     /// @{
    696     public:
    697       /// This function returns status information about the file. The type of
    698       /// path (file or directory) is updated to reflect the actual contents
    699       /// of the file system.
    700       /// @returns 0 on failure, with Error explaining why (if non-zero)
    701       /// @returns a pointer to a FileStatus structure on success.
    702       /// @brief Get file status.
    703       const FileStatus *getFileStatus(
    704         bool forceUpdate = false, ///< Force an update from the file system
    705         std::string *Error = 0    ///< Optional place to return an error msg.
    706       ) const;
    707 
    708     /// @}
    709     /// @name Data
    710     /// @{
    711     private:
    712       mutable FileStatus status; ///< Status information.
    713       mutable bool fsIsValid;    ///< Whether we've obtained it or not
    714 
    715     /// @}
    716   };
    717 
    718   /// This enumeration delineates the kinds of files that LLVM knows about.
    719   enum LLVMFileType {
    720     Unknown_FileType = 0,              ///< Unrecognized file
    721     Bitcode_FileType,                  ///< Bitcode file
    722     Archive_FileType,                  ///< ar style archive file
    723     ELF_Relocatable_FileType,          ///< ELF Relocatable object file
    724     ELF_Executable_FileType,           ///< ELF Executable image
    725     ELF_SharedObject_FileType,         ///< ELF dynamically linked shared lib
    726     ELF_Core_FileType,                 ///< ELF core image
    727     Mach_O_Object_FileType,            ///< Mach-O Object file
    728     Mach_O_Executable_FileType,        ///< Mach-O Executable
    729     Mach_O_FixedVirtualMemorySharedLib_FileType, ///< Mach-O Shared Lib, FVM
    730     Mach_O_Core_FileType,              ///< Mach-O Core File
    731     Mach_O_PreloadExecutable_FileType, ///< Mach-O Preloaded Executable
    732     Mach_O_DynamicallyLinkedSharedLib_FileType, ///< Mach-O dynlinked shared lib
    733     Mach_O_DynamicLinker_FileType,     ///< The Mach-O dynamic linker
    734     Mach_O_Bundle_FileType,            ///< Mach-O Bundle file
    735     Mach_O_DynamicallyLinkedSharedLibStub_FileType, ///< Mach-O Shared lib stub
    736     Mach_O_DSYMCompanion_FileType,     ///< Mach-O dSYM companion file
    737     COFF_FileType                      ///< COFF object file or lib
    738   };
    739 
    740   /// This utility function allows any memory block to be examined in order
    741   /// to determine its file type.
    742   LLVMFileType IdentifyFileType(const char*magic, unsigned length);
    743 
    744   /// This function can be used to copy the file specified by Src to the
    745   /// file specified by Dest. If an error occurs, Dest is removed.
    746   /// @returns true if an error occurs, false otherwise
    747   /// @brief Copy one file to another.
    748   bool CopyFile(const Path& Dest, const Path& Src, std::string* ErrMsg);
    749 
    750   /// This is the OS-specific path separator: a colon on Unix or a semicolon
    751   /// on Windows.
    752   extern const char PathSeparator;
    753 }
    754 
    755 }
    756 
    757 #endif
    758