include/wx/file.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        file.cpp
   3 // Purpose:     wxFile - encapsulates low-level "file descriptor"
   4 //              wxTempFile - safely replace the old file
   5 // Author:      Vadim Zeitlin
   6 // Modified by:
   7 // Created:     29/01/98
   8 // RCS-ID:      $Id$
   9 // Copyright:   (c) 1998 Vadim Zeitlin <zeitlin@dptmaths.ens-cachan.fr>
  10 // Licence:     wxWindows license
  11 /////////////////////////////////////////////////////////////////////////////
  12
  13 #ifndef   __FILEH__
  14 #define   __FILEH__
  15
  16 #ifdef __GNUG__
  17 #pragma interface "file.h"
  18 #endif
  19
  20 // ----------------------------------------------------------------------------
  21 // simple types
  22 // ----------------------------------------------------------------------------
  23
  24 #include  "wx/string.h"
  25 #include  "wx/filefn.h"
  26
  27 // define off_t
  28 #include  <sys/types.h>
  29
  30 #ifdef    _MSC_VER
  31   #define   off_t       _off_t
  32 #endif
  33
  34 // ----------------------------------------------------------------------------
  35 // constants
  36 // ----------------------------------------------------------------------------
  37
  38 // error return value for Seek() functions
  39 const off_t ofsInvalid = (off_t)-1;
  40
  41 // ----------------------------------------------------------------------------
  42 // class wxFile: raw file IO
  43 //
  44 // NB: for space efficiency this class has no virtual functions, including
  45 //     dtor which is _not_ virtual, so it shouldn't be used as a base class.
  46 // ----------------------------------------------------------------------------
  47 class WXDLLEXPORT wxFile
  48 {
  49 public:
  50   // more file constants
  51   // -------------------
  52
  53     // opening mode
  54   enum OpenMode { read, write, read_write, write_append };
  55     // standard values for file descriptor
  56   enum { fd_invalid = -1, fd_stdin, fd_stdout, fd_stderr };
  57     // seek type
  58   enum SeekMode { FromStart, FromEnd, FromCurrent };
  59
  60   // static functions
  61   // ----------------
  62   static bool Exists(const char *sz);  // also checks it's a regular file
  63
  64   // ctors
  65   // -----
  66     // def ctor
  67   wxFile() { m_fd = fd_invalid; }
  68     // open specified file (may fail, use IsOpened())
  69   wxFile(const char *szFileName, OpenMode mode = read);
  70     // attach to (already opened) file
  71   wxFile(int fd) { m_fd = fd; }
  72
  73   // open/close
  74   bool Create(const char *szFileName, bool bOverwrite = FALSE);
  75   bool Open(const char *szFileName, OpenMode mode = read);
  76   inline bool Close();  // Close is a NOP if not opened
  77
  78   // assign an existing file descriptor and get it back from wxFile object
  79   void Attach(int fd) { Close(); m_fd = fd; }
  80   void Detach()       { m_fd = fd_invalid;  }
  81   int  fd() const { return m_fd; }
  82
  83   // read/write (unbuffered)
  84     // returns number of bytes read or ofsInvalid on error
  85   off_t Read(void *pBuf, off_t nCount);
  86     // returns true on success
  87   bool Write(const void *pBuf, uint nCount);
  88     // returns true on success
  89   bool Write(const wxString& str) { return Write(str.c_str(), str.Len()); }
  90     // flush data not yet written
  91   bool Flush();
  92
  93   // file pointer operations (return ofsInvalid on failure)
  94     // move ptr ofs bytes related to start/current off_t/end of file
  95   off_t Seek(off_t ofs, SeekMode mode = FromStart);
  96     // move ptr to ofs bytes before the end
  97   off_t SeekEnd(off_t ofs = 0) { return Seek(ofs, FromEnd); }
  98     // get current off_t
  99   off_t Tell() const;
 100     // get current file length
 101   off_t Length() const;
 102
 103   // simple accessors
 104     // is file opened?
 105   bool IsOpened() const { return m_fd != fd_invalid; }
 106     // is end of file reached?
 107   bool Eof() const;
 108
 109   // dtor closes the file if opened
 110  ~wxFile();
 111
 112 private:
 113   // copy ctor and assignment operator are private because
 114   // it doesn't make sense to copy files this way:
 115   // attempt to do it will provoke a compile-time error.
 116   wxFile(const wxFile&);
 117   wxFile& operator=(const wxFile&);
 118
 119   int m_fd; // file descriptor or INVALID_FD if not opened
 120 };
 121
 122 // ----------------------------------------------------------------------------
 123 // class wxTempFile: if you want to replace another file, create an instance
 124 // of wxTempFile passing the name of the file to be replaced to the ctor. Then
 125 // you can write to wxTempFile and call Commit() function to replace the old
 126 // file (and close this one) or call Discard() to cancel the modification. If
 127 // you call neither of them, dtor will call Discard().
 128 // ----------------------------------------------------------------------------
 129 class wxTempFile
 130 {
 131 public:
 132   // ctors
 133     // default
 134   wxTempFile() { }
 135     // associates the temp file with the file to be replaced and opens it
 136   wxTempFile(const wxString& strName);
 137
 138   // open the temp file (strName is the name of file to be replaced)
 139   bool Open(const wxString& strName);
 140
 141   // is the file opened?
 142   bool IsOpened() const { return m_file.IsOpened(); }
 143
 144   // I/O (both functions return true on success, false on failure)
 145   bool Write(const void *p, uint n) { return m_file.Write(p, n); }
 146   bool Write(const wxString& str)   { return m_file.Write(str);  }
 147
 148   // different ways to close the file
 149     // validate changes and delete the old file of name m_strName
 150   bool Commit();
 151     // discard changes
 152   void Discard();
 153
 154   // dtor calls Discard() if file is still opened
 155  ~wxTempFile();
 156
 157 private:
 158   wxString  m_strName,  // name of the file to replace in Commit()
 159             m_strTemp;  // temporary file name
 160   wxFile    m_file;     // the temporary file
 161 };
 162
 163 #endif
 164         // __FILEH__