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 #include  "wx/defs.h"
  21
  22 #if wxUSE_FILE
  23
  24 #include  "wx/string.h"
  25 #include  "wx/filefn.h"
  26 #include  "wx/strconv.h"
  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 whether 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 wxInvalidOffset on error
 100   ssize_t Read(void *pBuf, size_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 wxInvalidOffset on failure)
 114     // move ptr ofs bytes related to start/current offset/end of file
 115   wxFileOffset Seek(wxFileOffset ofs, wxSeekMode mode = wxFromStart);
 116     // move ptr to ofs bytes before the end
 117   wxFileOffset SeekEnd(wxFileOffset ofs = 0) { return Seek(ofs, wxFromEnd); }
 118     // get current offset
 119   wxFileOffset Tell() const;
 120     // get current file length
 121   wxFileOffset 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 occurred?
 129   bool Error() const { return m_error; }
 130     // type such as disk or pipe
 131   wxFileKind GetKind() const { return wxGetFileKind(m_fd); }
 132
 133   // dtor closes the file if opened
 134   ~wxFile() { Close(); }
 135
 136 private:
 137   // copy ctor and assignment operator are private because
 138   // it doesn't make sense to copy files this way:
 139   // attempt to do it will provoke a compile-time error.
 140   wxFile(const wxFile&);
 141   wxFile& operator=(const wxFile&);
 142
 143   int m_fd; // file descriptor or INVALID_FD if not opened
 144   bool m_error; // error memory
 145 };
 146
 147 // ----------------------------------------------------------------------------
 148 // class wxTempFile: if you want to replace another file, create an instance
 149 // of wxTempFile passing the name of the file to be replaced to the ctor. Then
 150 // you can write to wxTempFile and call Commit() function to replace the old
 151 // file (and close this one) or call Discard() to cancel the modification. If
 152 // you call neither of them, dtor will call Discard().
 153 // ----------------------------------------------------------------------------
 154
 155 class WXDLLIMPEXP_BASE wxTempFile
 156 {
 157 public:
 158   // ctors
 159     // default
 160   wxTempFile() { }
 161     // associates the temp file with the file to be replaced and opens it
 162   wxTempFile(const wxString& strName);
 163
 164   // open the temp file (strName is the name of file to be replaced)
 165   bool Open(const wxString& strName);
 166
 167   // is the file opened?
 168   bool IsOpened() const { return m_file.IsOpened(); }
 169     // get current file length
 170   wxFileOffset Length() const { return m_file.Length(); }
 171     // move ptr ofs bytes related to start/current offset/end of file
 172   wxFileOffset Seek(wxFileOffset ofs, wxSeekMode mode = wxFromStart)
 173     { return m_file.Seek(ofs, mode); }
 174     // get current offset
 175   wxFileOffset Tell() const { return m_file.Tell(); }
 176
 177   // I/O (both functions return true on success, false on failure)
 178   bool Write(const void *p, size_t n) { return m_file.Write(p, n) == n; }
 179   bool Write(const wxString& str, wxMBConv& conv = wxConvUTF8)
 180     { return m_file.Write(str, conv); }
 181
 182   // different ways to close the file
 183     // validate changes and delete the old file of name m_strName
 184   bool Commit();
 185     // discard changes
 186   void Discard();
 187
 188   // dtor calls Discard() if file is still opened
 189  ~wxTempFile();
 190
 191 private:
 192   // no copy ctor/assignment operator
 193   wxTempFile(const wxTempFile&);
 194   wxTempFile& operator=(const wxTempFile&);
 195
 196   wxString  m_strName,  // name of the file to replace in Commit()
 197             m_strTemp;  // temporary file name
 198   wxFile    m_file;     // the temporary file
 199 };
 200
 201 #endif // wxUSE_FILE
 202
 203 #endif // _WX_FILEH__