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 wxString& 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 wxString& 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 wxString& fileName, 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 wxString& fileName, bool bOverwrite = false,
  84               int access = wxS_DEFAULT);
  85   bool Open(const wxString& fileName, 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 = wxMBConvUTF8());
 101     // flush data not yet written
 102   bool Flush();
 103
 104   // file pointer operations (return wxInvalidOffset on failure)
 105     // move ptr ofs bytes related to start/current offset/end of file
 106   wxFileOffset Seek(wxFileOffset ofs, wxSeekMode mode = wxFromStart);
 107     // move ptr to ofs bytes before the end
 108   wxFileOffset SeekEnd(wxFileOffset ofs = 0) { return Seek(ofs, wxFromEnd); }
 109     // get current offset
 110   wxFileOffset Tell() const;
 111     // get current file length
 112   wxFileOffset Length() const;
 113
 114   // simple accessors
 115     // is file opened?
 116   bool IsOpened() const { return m_fd != fd_invalid; }
 117     // is end of file reached?
 118   bool Eof() const;
 119     // has an error occurred?
 120   bool Error() const { return m_error; }
 121     // type such as disk or pipe
 122   wxFileKind GetKind() const { return wxGetFileKind(m_fd); }
 123
 124   // dtor closes the file if opened
 125   ~wxFile() { Close(); }
 126
 127 private:
 128   // copy ctor and assignment operator are private because
 129   // it doesn't make sense to copy files this way:
 130   // attempt to do it will provoke a compile-time error.
 131   wxFile(const wxFile&);
 132   wxFile& operator=(const wxFile&);
 133
 134   int m_fd; // file descriptor or INVALID_FD if not opened
 135   bool m_error; // error memory
 136 };
 137
 138 // ----------------------------------------------------------------------------
 139 // class wxTempFile: if you want to replace another file, create an instance
 140 // of wxTempFile passing the name of the file to be replaced to the ctor. Then
 141 // you can write to wxTempFile and call Commit() function to replace the old
 142 // file (and close this one) or call Discard() to cancel the modification. If
 143 // you call neither of them, dtor will call Discard().
 144 // ----------------------------------------------------------------------------
 145
 146 class WXDLLIMPEXP_BASE wxTempFile
 147 {
 148 public:
 149   // ctors
 150     // default
 151   wxTempFile() { }
 152     // associates the temp file with the file to be replaced and opens it
 153   wxTempFile(const wxString& strName);
 154
 155   // open the temp file (strName is the name of file to be replaced)
 156   bool Open(const wxString& strName);
 157
 158   // is the file opened?
 159   bool IsOpened() const { return m_file.IsOpened(); }
 160     // get current file length
 161   wxFileOffset Length() const { return m_file.Length(); }
 162     // move ptr ofs bytes related to start/current offset/end of file
 163   wxFileOffset Seek(wxFileOffset ofs, wxSeekMode mode = wxFromStart)
 164     { return m_file.Seek(ofs, mode); }
 165     // get current offset
 166   wxFileOffset Tell() const { return m_file.Tell(); }
 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) == n; }
 170   bool Write(const wxString& str, const wxMBConv& conv = wxMBConvUTF8())
 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__