include/wx/file.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        file.h
   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 licence
  11 /////////////////////////////////////////////////////////////////////////////
  12
  13 #ifndef _WX_FILEH__
  14 #define _WX_FILEH__
  15
  16 #if defined(__GNUG__) && !defined(NO_GCC_PRAGMA)
  17 #pragma interface "file.h"
  18 #endif
  19
  20 #ifndef WX_PRECOMP
  21   #include  "wx/string.h"
  22   #include  "wx/filefn.h"
  23   #include  "wx/strconv.h"
  24 #endif
  25
  26 #if wxUSE_FILE
  27
  28 // ----------------------------------------------------------------------------
  29 // constants
  30 // ----------------------------------------------------------------------------
  31
  32 // we redefine these constants here because S_IREAD &c are _not_ standard
  33 // however, we do assume that the values correspond to the Unix umask bits
  34 #define wxS_IRUSR 00400
  35 #define wxS_IWUSR 00200
  36 #define wxS_IXUSR 00100
  37
  38 #define wxS_IRGRP 00040
  39 #define wxS_IWGRP 00020
  40 #define wxS_IXGRP 00010
  41
  42 #define wxS_IROTH 00004
  43 #define wxS_IWOTH 00002
  44 #define wxS_IXOTH 00001
  45
  46 // default mode for the new files: corresponds to umask 022
  47 #define wxS_DEFAULT   (wxS_IRUSR | wxS_IWUSR | wxS_IRGRP | wxS_IWGRP |\
  48                        wxS_IROTH | wxS_IWOTH)
  49
  50 // ----------------------------------------------------------------------------
  51 // class wxFile: raw file IO
  52 //
  53 // NB: for space efficiency this class has no virtual functions, including
  54 //     dtor which is _not_ virtual, so it shouldn't be used as a base class.
  55 // ----------------------------------------------------------------------------
  56
  57 class WXDLLIMPEXP_BASE wxFile
  58 {
  59 public:
  60   // more file constants
  61   // -------------------
  62     // opening mode
  63   enum OpenMode { read, write, read_write, write_append, write_excl };
  64     // standard values for file descriptor
  65   enum { fd_invalid = -1, fd_stdin, fd_stdout, fd_stderr };
  66
  67   // static functions
  68   // ----------------
  69     // check whether a regular file by this name exists
  70   static bool Exists(const wxChar *name);
  71     // check whetther we can access the given file in given mode
  72     // (only read and write make sense here)
  73   static bool Access(const wxChar *name, OpenMode mode);
  74
  75   // ctors
  76   // -----
  77     // def ctor
  78   wxFile() { m_fd = fd_invalid; m_error = false; }
  79     // open specified file (may fail, use IsOpened())
  80   wxFile(const wxChar *szFileName, OpenMode mode = read);
  81     // attach to (already opened) file
  82   wxFile(int fd) { m_fd = fd; m_error = false; }
  83
  84   // open/close
  85     // create a new file (with the default value of bOverwrite, it will fail if
  86     // the file already exists, otherwise it will overwrite it and succeed)
  87   bool Create(const wxChar *szFileName, bool bOverwrite = FALSE,
  88               int access = wxS_DEFAULT);
  89   bool Open(const wxChar *szFileName, OpenMode mode = read,
  90             int access = wxS_DEFAULT);
  91   bool Close();  // Close is a NOP if not opened
  92
  93   // assign an existing file descriptor and get it back from wxFile object
  94   void Attach(int fd) { Close(); m_fd = fd; m_error = false; }
  95   void Detach()       { m_fd = fd_invalid;  }
  96   int  fd() const { return m_fd; }
  97
  98   // read/write (unbuffered)
  99     // returns number of bytes read or ofsInvalid on error
 100   off_t Read(void *pBuf, off_t nCount);
 101     // returns the number of bytes written
 102   size_t Write(const void *pBuf, size_t nCount);
 103     // returns true on success
 104   bool Write(const wxString& s, wxMBConv& conv = wxConvUTF8)
 105   {
 106       const wxWX2MBbuf buf = s.mb_str(conv);
 107       size_t size = strlen(buf);
 108       return Write((const char *) buf, size) == size;
 109   }
 110     // flush data not yet written
 111   bool Flush();
 112
 113   // file pointer operations (return ofsInvalid on failure)
 114     // move ptr ofs bytes related to start/current off_t/end of file
 115   off_t Seek(off_t ofs, wxSeekMode mode = wxFromStart);
 116     // move ptr to ofs bytes before the end
 117   off_t SeekEnd(off_t ofs = 0) { return Seek(ofs, wxFromEnd); }
 118     // get current off_t
 119   off_t Tell() const;
 120     // get current file length
 121   off_t Length() const;
 122
 123   // simple accessors
 124     // is file opened?
 125   bool IsOpened() const { return m_fd != fd_invalid; }
 126     // is end of file reached?
 127   bool Eof() const;
 128     // has an error occured?
 129   bool Error() const { return m_error; }
 130
 131   // dtor closes the file if opened
 132   ~wxFile() { Close(); }
 133
 134 private:
 135   // copy ctor and assignment operator are private because
 136   // it doesn't make sense to copy files this way:
 137   // attempt to do it will provoke a compile-time error.
 138   wxFile(const wxFile&);
 139   wxFile& operator=(const wxFile&);
 140
 141   int m_fd; // file descriptor or INVALID_FD if not opened
 142   bool m_error; // error memory
 143 };
 144
 145 // ----------------------------------------------------------------------------
 146 // class wxTempFile: if you want to replace another file, create an instance
 147 // of wxTempFile passing the name of the file to be replaced to the ctor. Then
 148 // you can write to wxTempFile and call Commit() function to replace the old
 149 // file (and close this one) or call Discard() to cancel the modification. If
 150 // you call neither of them, dtor will call Discard().
 151 // ----------------------------------------------------------------------------
 152
 153 class WXDLLIMPEXP_BASE wxTempFile
 154 {
 155 public:
 156   // ctors
 157     // default
 158   wxTempFile() { }
 159     // associates the temp file with the file to be replaced and opens it
 160   wxTempFile(const wxString& strName);
 161
 162   // open the temp file (strName is the name of file to be replaced)
 163   bool Open(const wxString& strName);
 164
 165   // is the file opened?
 166   bool IsOpened() const { return m_file.IsOpened(); }
 167
 168   // I/O (both functions return true on success, false on failure)
 169   bool Write(const void *p, size_t n) { return m_file.Write(p, n) != 0; }
 170   bool Write(const wxString& str, wxMBConv& conv = wxConvUTF8)
 171     { return m_file.Write(str, conv); }
 172
 173   // different ways to close the file
 174     // validate changes and delete the old file of name m_strName
 175   bool Commit();
 176     // discard changes
 177   void Discard();
 178
 179   // dtor calls Discard() if file is still opened
 180  ~wxTempFile();
 181
 182 private:
 183   // no copy ctor/assignment operator
 184   wxTempFile(const wxTempFile&);
 185   wxTempFile& operator=(const wxTempFile&);
 186
 187   wxString  m_strName,  // name of the file to replace in Commit()
 188             m_strTemp;  // temporary file name
 189   wxFile    m_file;     // the temporary file
 190 };
 191
 192 #endif // wxUSE_FILE
 193
 194 #endif // _WX_FILEH__