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: allow reading/writing them to everybody but
  43 // the effective file mode will be set after anding this value with umask and
  44 // so won't include wxS_IW{GRP,OTH} for the default 022 umask value
  45 #define wxS_DEFAULT \
  46     (wxS_IRUSR | wxS_IWUSR | wxS_IRGRP | wxS_IWGRP | wxS_IROTH | wxS_IWOTH)
  47
  48 // ----------------------------------------------------------------------------
  49 // class wxFile: raw file IO
  50 //
  51 // NB: for space efficiency this class has no virtual functions, including
  52 //     dtor which is _not_ virtual, so it shouldn't be used as a base class.
  53 // ----------------------------------------------------------------------------
  54
  55 class WXDLLIMPEXP_BASE wxFile
  56 {
  57 public:
  58   // more file constants
  59   // -------------------
  60     // opening mode
  61   enum OpenMode { read, write, read_write, write_append, write_excl };
  62     // standard values for file descriptor
  63   enum { fd_invalid = -1, fd_stdin, fd_stdout, fd_stderr };
  64
  65   // static functions
  66   // ----------------
  67     // check whether a regular file by this name exists
  68   static bool Exists(const wxString& name);
  69     // check whether we can access the given file in given mode
  70     // (only read and write make sense here)
  71   static bool Access(const wxString& name, OpenMode mode);
  72
  73   // ctors
  74   // -----
  75     // def ctor
  76   wxFile() { m_fd = fd_invalid; m_error = false; }
  77     // open specified file (may fail, use IsOpened())
  78   wxFile(const wxString& fileName, OpenMode mode = read);
  79     // attach to (already opened) file
  80   wxFile(int lfd) { m_fd = lfd; m_error = false; }
  81
  82   // open/close
  83     // create a new file (with the default value of bOverwrite, it will fail if
  84     // the file already exists, otherwise it will overwrite it and succeed)
  85   bool Create(const wxString& fileName, bool bOverwrite = false,
  86               int access = wxS_DEFAULT);
  87   bool Open(const wxString& fileName, OpenMode mode = read,
  88             int access = wxS_DEFAULT);
  89   bool Close();  // Close is a NOP if not opened
  90
  91   // assign an existing file descriptor and get it back from wxFile object
  92   void Attach(int lfd) { Close(); m_fd = lfd; m_error = false; }
  93   void Detach()       { m_fd = fd_invalid;  }
  94   int  fd() const { return m_fd; }
  95
  96   // read/write (unbuffered)
  97     // returns number of bytes read or wxInvalidOffset on error
  98   ssize_t Read(void *pBuf, size_t nCount);
  99     // returns the number of bytes written
 100   size_t Write(const void *pBuf, size_t nCount);
 101     // returns true on success
 102   bool Write(const wxString& s, const wxMBConv& conv = wxMBConvUTF8());
 103     // flush data not yet written
 104   bool Flush();
 105
 106   // file pointer operations (return wxInvalidOffset on failure)
 107     // move ptr ofs bytes related to start/current offset/end of file
 108   wxFileOffset Seek(wxFileOffset ofs, wxSeekMode mode = wxFromStart);
 109     // move ptr to ofs bytes before the end
 110   wxFileOffset SeekEnd(wxFileOffset ofs = 0) { return Seek(ofs, wxFromEnd); }
 111     // get current offset
 112   wxFileOffset Tell() const;
 113     // get current file length
 114   wxFileOffset Length() const;
 115
 116   // simple accessors
 117     // is file opened?
 118   bool IsOpened() const { return m_fd != fd_invalid; }
 119     // is end of file reached?
 120   bool Eof() const;
 121     // has an error occurred?
 122   bool Error() const { return m_error; }
 123     // type such as disk or pipe
 124   wxFileKind GetKind() const { return wxGetFileKind(m_fd); }
 125
 126   // dtor closes the file if opened
 127   ~wxFile() { Close(); }
 128
 129 private:
 130   // copy ctor and assignment operator are private because
 131   // it doesn't make sense to copy files this way:
 132   // attempt to do it will provoke a compile-time error.
 133   wxFile(const wxFile&);
 134   wxFile& operator=(const wxFile&);
 135
 136   int m_fd; // file descriptor or INVALID_FD if not opened
 137   bool m_error; // error memory
 138 };
 139
 140 // ----------------------------------------------------------------------------
 141 // class wxTempFile: if you want to replace another file, create an instance
 142 // of wxTempFile passing the name of the file to be replaced to the ctor. Then
 143 // you can write to wxTempFile and call Commit() function to replace the old
 144 // file (and close this one) or call Discard() to cancel the modification. If
 145 // you call neither of them, dtor will call Discard().
 146 // ----------------------------------------------------------------------------
 147
 148 class WXDLLIMPEXP_BASE wxTempFile
 149 {
 150 public:
 151   // ctors
 152     // default
 153   wxTempFile() { }
 154     // associates the temp file with the file to be replaced and opens it
 155   wxTempFile(const wxString& strName);
 156
 157   // open the temp file (strName is the name of file to be replaced)
 158   bool Open(const wxString& strName);
 159
 160   // is the file opened?
 161   bool IsOpened() const { return m_file.IsOpened(); }
 162     // get current file length
 163   wxFileOffset Length() const { return m_file.Length(); }
 164     // move ptr ofs bytes related to start/current offset/end of file
 165   wxFileOffset Seek(wxFileOffset ofs, wxSeekMode mode = wxFromStart)
 166     { return m_file.Seek(ofs, mode); }
 167     // get current offset
 168   wxFileOffset Tell() const { return m_file.Tell(); }
 169
 170   // I/O (both functions return true on success, false on failure)
 171   bool Write(const void *p, size_t n) { return m_file.Write(p, n) == n; }
 172   bool Write(const wxString& str, const wxMBConv& conv = wxMBConvUTF8())
 173     { return m_file.Write(str, conv); }
 174
 175   // different ways to close the file
 176     // validate changes and delete the old file of name m_strName
 177   bool Commit();
 178     // discard changes
 179   void Discard();
 180
 181   // dtor calls Discard() if file is still opened
 182  ~wxTempFile();
 183
 184 private:
 185   // no copy ctor/assignment operator
 186   wxTempFile(const wxTempFile&);
 187   wxTempFile& operator=(const wxTempFile&);
 188
 189   wxString  m_strName,  // name of the file to replace in Commit()
 190             m_strTemp;  // temporary file name
 191   wxFile    m_file;     // the temporary file
 192 };
 193
 194 #endif // wxUSE_FILE
 195
 196 #endif // _WX_FILEH__