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      1 //===- FileHandle.h -------------------------------------------------------===//
      2 //
      3 //                     The MCLinker Project
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 #ifndef MCLD_SUPPORT_FILEHANDLE_H
     10 #define MCLD_SUPPORT_FILEHANDLE_H
     11 #include <mcld/Support/Path.h>
     12 #include <mcld/ADT/Flags.h>
     13 
     14 #include <errno.h>
     15 
     16 namespace mcld {
     17 
     18 /** \class FileHandle
     19  *  \brief FileHandle class provides an interface for reading from and writing
     20  *  to files.
     21  *
     22  *  Operators of FileHandle should neither throw exceptions nor call expressive
     23  *  diagnostic output.
     24  */
     25 class FileHandle
     26 {
     27 public:
     28   enum IOState
     29   {
     30     GoodBit    = 0,       // no error
     31     BadBit     = 1L << 0, // error due to the inappropriate operation
     32     EOFBit     = 1L << 1, // reached End-Of-File
     33     FailBit    = 1L << 2, // internal logic fail
     34     DeputedBit = 1L << 3, // the file descriptor is delegated
     35     IOStateEnd = 1L << 16
     36   };
     37 
     38   enum OpenModeEnum
     39   {
     40     NotOpen   = 0x00,
     41     ReadOnly  = 0x01,
     42     WriteOnly = 0x02,
     43     ReadWrite = ReadOnly | WriteOnly,
     44     Append    = 0x04,
     45     Create    = 0x08,
     46     Truncate  = 0x10,
     47     Unknown   = 0xFF
     48   };
     49 
     50   typedef Flags<OpenModeEnum> OpenMode;
     51 
     52   enum PermissionEnum
     53   {
     54     ReadOwner   = 0x0400,
     55     WriteOwner  = 0x0200,
     56     ExeOwner    = 0x0100,
     57     ReadGroup   = 0x0040,
     58     WriteGroup  = 0x0020,
     59     ExeGroup    = 0x0010,
     60     ReadOther   = 0x0004,
     61     WriteOther  = 0x0002,
     62     ExeOther    = 0x0001,
     63     System      = 0xFFFF
     64   };
     65 
     66   typedef Flags<PermissionEnum> Permission;
     67 
     68 public:
     69   FileHandle();
     70 
     71   ~FileHandle();
     72 
     73   /// open - open the file.
     74   /// @return if we meet any trouble during opening the file, return false.
     75   ///         use rdstate() to see what happens.
     76   bool open(const sys::fs::Path& pPath,
     77             OpenMode pMode,
     78             Permission pPerm = System);
     79 
     80   bool delegate(int pFD, OpenMode pMode = Unknown);
     81 
     82   bool close();
     83 
     84   void setState(IOState pState);
     85 
     86   void cleanState(IOState pState = GoodBit);
     87 
     88   // truncate - truncate the file up to the pSize.
     89   bool truncate(size_t pSize);
     90 
     91   bool read(void* pMemBuffer, size_t pStartOffset, size_t pLength);
     92 
     93   bool write(const void* pMemBuffer, size_t pStartOffset, size_t pLength);
     94 
     95   bool mmap(void*& pMemBuffer, size_t pStartOffset, size_t pLength);
     96 
     97   bool munmap(void* pMemBuffer, size_t pLength);
     98 
     99   // -----  observers  ----- //
    100   const sys::fs::Path& path() const
    101   { return m_Path; }
    102 
    103   size_t size() const
    104   { return m_Size; }
    105 
    106   int handler() const
    107   { return m_Handler; }
    108 
    109   uint16_t rdstate() const
    110   { return m_State; }
    111 
    112   bool isOpened() const;
    113 
    114   bool isGood() const;
    115 
    116   bool isBad() const;
    117 
    118   bool isFailed() const;
    119 
    120   bool isOwned() const;
    121 
    122   bool isReadable() const;
    123 
    124   bool isWritable() const;
    125 
    126   bool isReadWrite() const;
    127 
    128   int error() const { return errno; }
    129 
    130 private:
    131   sys::fs::Path m_Path;
    132   int m_Handler;
    133   unsigned int m_Size;
    134   uint16_t m_State;
    135   OpenMode m_OpenMode;
    136 };
    137 
    138 } // namespace of mcld
    139 
    140 #endif
    141 
    142