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(__APPLE__)
  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 class WXDLLEXPORT wxFile
  57 {
  58 public:
  59   // more file constants
  60   // -------------------
  61     // opening mode
  62   enum OpenMode { read, write, read_write, write_append, write_excl };
  63     // standard values for file descriptor
  64   enum { fd_invalid = -1, fd_stdin, fd_stdout, fd_stderr };
  65
  66   // static functions
  67   // ----------------
  68     // check whether a regular file by this name exists
  69   static bool Exists(const wxChar *name);
  70     // check whetther we can access the given file in given mode
  71     // (only read and write make sense here)
  72   static bool Access(const wxChar *name, OpenMode mode);
  73
  74   // ctors
  75   // -----
  76     // def ctor
  77   wxFile() { m_fd = fd_invalid; }
  78     // open specified file (may fail, use IsOpened())
  79   wxFile(const wxChar *szFileName, OpenMode mode = read);
  80     // attach to (already opened) file
  81   wxFile(int fd) { m_fd = fd; }
  82
  83   // open/close
  84     // create a new file (with the default value of bOverwrite, it will fail if
  85     // the file already exists, otherwise it will overwrite it and succeed)
  86   bool Create(const wxChar *szFileName, bool bOverwrite = FALSE,
  87               int access = wxS_DEFAULT);
  88   bool Open(const wxChar *szFileName, OpenMode mode = read,
  89             int access = wxS_DEFAULT);
  90   bool Close();  // Close is a NOP if not opened
  91
  92   // assign an existing file descriptor and get it back from wxFile object
  93   void Attach(int fd) { Close(); m_fd = fd; }
  94   void Detach()       { m_fd = fd_invalid;  }
  95   int  fd() const { return m_fd; }
  96
  97   // read/write (unbuffered)
  98     // returns number of bytes read or ofsInvalid on error
  99   off_t Read(void *pBuf, off_t nCount);
 100     // returns the number of bytes written
 101   size_t Write(const void *pBuf, size_t nCount);
 102     // returns true on success
 103   bool Write(const wxString& s, wxMBConv& conv = wxConvUTF8)
 104   {
 105       const wxWX2MBbuf buf = s.mb_str(conv);
 106       size_t size = strlen(buf);
 107       return Write((const char *) buf, size) == size;
 108   }
 109     // flush data not yet written
 110   bool Flush();
 111
 112   // file pointer operations (return ofsInvalid on failure)
 113     // move ptr ofs bytes related to start/current off_t/end of file
 114   off_t Seek(off_t ofs, wxSeekMode mode = wxFromStart);
 115     // move ptr to ofs bytes before the end
 116   off_t SeekEnd(off_t ofs = 0) { return Seek(ofs, wxFromEnd); }
 117     // get current off_t
 118   off_t Tell() const;
 119     // get current file length
 120   off_t Length() const;
 121
 122   // simple accessors
 123     // is file opened?
 124   bool IsOpened() const { return m_fd != fd_invalid; }
 125     // is end of file reached?
 126   bool Eof() const;
 127     // has an error occured?
 128   bool Error() const { return m_error; }
 129
 130   // dtor closes the file if opened
 131   ~wxFile() { Close(); }
 132
 133 private:
 134   // copy ctor and assignment operator are private because
 135   // it doesn't make sense to copy files this way:
 136   // attempt to do it will provoke a compile-time error.
 137   wxFile(const wxFile&);
 138   wxFile& operator=(const wxFile&);
 139
 140   int m_fd; // file descriptor or INVALID_FD if not opened
 141   bool m_error; // error memory
 142 };
 143
 144 // ----------------------------------------------------------------------------
 145 // class wxTempFile: if you want to replace another file, create an instance
 146 // of wxTempFile passing the name of the file to be replaced to the ctor. Then
 147 // you can write to wxTempFile and call Commit() function to replace the old
 148 // file (and close this one) or call Discard() to cancel the modification. If
 149 // you call neither of them, dtor will call Discard().
 150 // ----------------------------------------------------------------------------
 151 class WXDLLEXPORT wxTempFile
 152 {
 153 public:
 154   // ctors
 155     // default
 156   wxTempFile() { }
 157     // associates the temp file with the file to be replaced and opens it
 158   wxTempFile(const wxString& strName);
 159
 160   // open the temp file (strName is the name of file to be replaced)
 161   bool Open(const wxString& strName);
 162
 163   // is the file opened?
 164   bool IsOpened() const { return m_file.IsOpened(); }
 165
 166   // I/O (both functions return true on success, false on failure)
 167   bool Write(const void *p, size_t n) { return m_file.Write(p, n) != 0; }
 168   bool Write(const wxString& str, wxMBConv& conv = wxConvUTF8)
 169     { return m_file.Write(str, conv); }
 170
 171   // different ways to close the file
 172     // validate changes and delete the old file of name m_strName
 173   bool Commit();
 174     // discard changes
 175   void Discard();
 176
 177   // dtor calls Discard() if file is still opened
 178  ~wxTempFile();
 179
 180 private:
 181   // no copy ctor/assignment operator
 182   wxTempFile(const wxTempFile&);
 183   wxTempFile& operator=(const wxTempFile&);
 184
 185   wxString  m_strName,  // name of the file to replace in Commit()
 186             m_strTemp;  // temporary file name
 187   wxFile    m_file;     // the temporary file
 188 };
 189
 190 #endif // wxUSE_FILE
 191
 192 #endif // _WX_FILEH__