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 #include  "wx/defs.h"
  17
  18 #if wxUSE_FILE
  19
  20 #include  "wx/string.h"
  21 #include  "wx/filefn.h"
  22 #include  "wx/strconv.h"
  23
  24 // ----------------------------------------------------------------------------
  25 // constants
  26 // ----------------------------------------------------------------------------
  27
  28 // we redefine these constants here because S_IREAD &c are _not_ standard
  29 // however, we do assume that the values correspond to the Unix umask bits
  30 #define wxS_IRUSR 00400
  31 #define wxS_IWUSR 00200
  32 #define wxS_IXUSR 00100
  33
  34 #define wxS_IRGRP 00040
  35 #define wxS_IWGRP 00020
  36 #define wxS_IXGRP 00010
  37
  38 #define wxS_IROTH 00004
  39 #define wxS_IWOTH 00002
  40 #define wxS_IXOTH 00001
  41
  42 // default mode for the new files: corresponds to umask 022
  43 #define wxS_DEFAULT   (wxS_IRUSR | wxS_IWUSR | wxS_IRGRP | wxS_IWGRP |\
  44                        wxS_IROTH | wxS_IWOTH)
  45
  46 // ----------------------------------------------------------------------------
  47 // class wxFile: raw file IO
  48 //
  49 // NB: for space efficiency this class has no virtual functions, including
  50 //     dtor which is _not_ virtual, so it shouldn't be used as a base class.
  51 // ----------------------------------------------------------------------------
  52
  53 class WXDLLIMPEXP_BASE wxFile
  54 {
  55 public:
  56   // more file constants
  57   // -------------------
  58     // opening mode
  59   enum OpenMode { read, write, read_write, write_append, write_excl };
  60     // standard values for file descriptor
  61   enum { fd_invalid = -1, fd_stdin, fd_stdout, fd_stderr };
  62
  63   // static functions
  64   // ----------------
  65     // check whether a regular file by this name exists
  66   static bool Exists(const wxChar *name);
  67     // check whether we can access the given file in given mode
  68     // (only read and write make sense here)
  69   static bool Access(const wxChar *name, OpenMode mode);
  70
  71   // ctors
  72   // -----
  73     // def ctor
  74   wxFile() { m_fd = fd_invalid; m_error = false; }
  75     // open specified file (may fail, use IsOpened())
  76   wxFile(const wxChar *szFileName, OpenMode mode = read);
  77     // attach to (already opened) file
  78   wxFile(int lfd) { m_fd = lfd; m_error = false; }
  79
  80   // open/close
  81     // create a new file (with the default value of bOverwrite, it will fail if
  82     // the file already exists, otherwise it will overwrite it and succeed)
  83   bool Create(const wxChar *szFileName, bool bOverwrite = false,
  84               int access = wxS_DEFAULT);
  85   bool Open(const wxChar *szFileName, OpenMode mode = read,
  86             int access = wxS_DEFAULT);
  87   bool Close();  // Close is a NOP if not opened
  88
  89   // assign an existing file descriptor and get it back from wxFile object
  90   void Attach(int lfd) { Close(); m_fd = lfd; m_error = false; }
  91   void Detach()       { m_fd = fd_invalid;  }
  92   int  fd() const { return m_fd; }
  93
  94   // read/write (unbuffered)
  95     // returns number of bytes read or wxInvalidOffset on error
  96   ssize_t Read(void *pBuf, size_t nCount);
  97     // returns the number of bytes written
  98   size_t Write(const void *pBuf, size_t nCount);
  99     // returns true on success
 100   bool Write(const wxString& s, const wxMBConv& conv = wxConvUTF8)
 101   {
 102       const wxWX2MBbuf buf = s.mb_str(conv);
 103       if (buf)
 104       {
 105               size_t size = strlen(buf);
 106               return Write((const char *) buf, size) == size;
 107           }
 108       else
 109           return false;
 110   }
 111     // flush data not yet written
 112   bool Flush();
 113
 114   // file pointer operations (return wxInvalidOffset on failure)
 115     // move ptr ofs bytes related to start/current offset/end of file
 116   wxFileOffset Seek(wxFileOffset ofs, wxSeekMode mode = wxFromStart);
 117     // move ptr to ofs bytes before the end
 118   wxFileOffset SeekEnd(wxFileOffset ofs = 0) { return Seek(ofs, wxFromEnd); }
 119     // get current offset
 120   wxFileOffset Tell() const;
 121     // get current file length
 122   wxFileOffset Length() const;
 123
 124   // simple accessors
 125     // is file opened?
 126   bool IsOpened() const { return m_fd != fd_invalid; }
 127     // is end of file reached?
 128   bool Eof() const;
 129     // has an error occurred?
 130   bool Error() const { return m_error; }
 131     // type such as disk or pipe
 132   wxFileKind GetKind() const { return wxGetFileKind(m_fd); }
 133
 134   // dtor closes the file if opened
 135   ~wxFile() { Close(); }
 136
 137 private:
 138   // copy ctor and assignment operator are private because
 139   // it doesn't make sense to copy files this way:
 140   // attempt to do it will provoke a compile-time error.
 141   wxFile(const wxFile&);
 142   wxFile& operator=(const wxFile&);
 143
 144   int m_fd; // file descriptor or INVALID_FD if not opened
 145   bool m_error; // error memory
 146 };
 147
 148 // ----------------------------------------------------------------------------
 149 // class wxTempFile: if you want to replace another file, create an instance
 150 // of wxTempFile passing the name of the file to be replaced to the ctor. Then
 151 // you can write to wxTempFile and call Commit() function to replace the old
 152 // file (and close this one) or call Discard() to cancel the modification. If
 153 // you call neither of them, dtor will call Discard().
 154 // ----------------------------------------------------------------------------
 155
 156 class WXDLLIMPEXP_BASE wxTempFile
 157 {
 158 public:
 159   // ctors
 160     // default
 161   wxTempFile() { }
 162     // associates the temp file with the file to be replaced and opens it
 163   wxTempFile(const wxString& strName);
 164
 165   // open the temp file (strName is the name of file to be replaced)
 166   bool Open(const wxString& strName);
 167
 168   // is the file opened?
 169   bool IsOpened() const { return m_file.IsOpened(); }
 170     // get current file length
 171   wxFileOffset Length() const { return m_file.Length(); }
 172     // move ptr ofs bytes related to start/current offset/end of file
 173   wxFileOffset Seek(wxFileOffset ofs, wxSeekMode mode = wxFromStart)
 174     { return m_file.Seek(ofs, mode); }
 175     // get current offset
 176   wxFileOffset Tell() const { return m_file.Tell(); }
 177
 178   // I/O (both functions return true on success, false on failure)
 179   bool Write(const void *p, size_t n) { return m_file.Write(p, n) == n; }
 180   bool Write(const wxString& str, const wxMBConv& conv = wxConvUTF8)
 181     { return m_file.Write(str, conv); }
 182
 183   // different ways to close the file
 184     // validate changes and delete the old file of name m_strName
 185   bool Commit();
 186     // discard changes
 187   void Discard();
 188
 189   // dtor calls Discard() if file is still opened
 190  ~wxTempFile();
 191
 192 private:
 193   // no copy ctor/assignment operator
 194   wxTempFile(const wxTempFile&);
 195   wxTempFile& operator=(const wxTempFile&);
 196
 197   wxString  m_strName,  // name of the file to replace in Commit()
 198             m_strTemp;  // temporary file name
 199   wxFile    m_file;     // the temporary file
 200 };
 201
 202 #endif // wxUSE_FILE
 203
 204 #endif // _WX_FILEH__