include/wx/file.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        file.cpp
   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 license
  11 /////////////////////////////////////////////////////////////////////////////
  12
  13 #ifndef   __FILEH__
  14 #define   __FILEH__
  15
  16 #ifdef __GNUG__
  17 #pragma interface "file.h"
  18 #endif
  19
  20 #include  "wx/string.h"
  21 #include  "wx/filefn.h"
  22
  23 // ----------------------------------------------------------------------------
  24 // constants
  25 // ----------------------------------------------------------------------------
  26
  27 // we redefine these constants here because S_IREAD &c are _not_ standard
  28 // however, we do assume that the values correspond to the Unix umask bits
  29 #define wxS_IRUSR 00400
  30 #define wxS_IWUSR 00200
  31 #define wxS_IXUSR 00100
  32
  33 #define wxS_IRGRP 00040
  34 #define wxS_IWGRP 00020
  35 #define wxS_IXGRP 00010
  36
  37 #define wxS_IROTH 00004
  38 #define wxS_IWOTH 00002
  39 #define wxS_IXOTH 00001
  40
  41 // default mode for the new files: corresponds to umask 022
  42 #define wxS_DEFAULT   (wxS_IRUSR | wxS_IWUSR | wxS_IRGRP | wxS_IWGRP |\
  43                        wxS_IROTH | wxS_IWOTH)
  44
  45 // ----------------------------------------------------------------------------
  46 // class wxFile: raw file IO
  47 //
  48 // NB: for space efficiency this class has no virtual functions, including
  49 //     dtor which is _not_ virtual, so it shouldn't be used as a base class.
  50 // ----------------------------------------------------------------------------
  51 class WXDLLEXPORT wxFile
  52 {
  53 public:
  54   // more file constants
  55   // -------------------
  56
  57     // opening mode
  58   enum OpenMode { read, write, read_write, write_append };
  59     // standard values for file descriptor
  60   enum { fd_invalid = -1, fd_stdin, fd_stdout, fd_stderr };
  61
  62   // static functions
  63   // ----------------
  64   static bool Exists(const char *sz);  // also checks it's a regular file
  65
  66   // ctors
  67   // -----
  68     // def ctor
  69   wxFile() { m_fd = fd_invalid; }
  70     // open specified file (may fail, use IsOpened())
  71   wxFile(const char *szFileName, OpenMode mode = read);
  72     // attach to (already opened) file
  73   wxFile(int fd) { m_fd = fd; }
  74
  75   // open/close
  76     // create a new file (with the default value of bOverwrite, it will fail if
  77     // the file already exists, otherwise it will overwrite it and succeed)
  78   bool Create(const char *szFileName, bool bOverwrite = FALSE,
  79               int access = wxS_DEFAULT);
  80   bool Open(const char *szFileName, OpenMode mode = read,
  81             int access = wxS_DEFAULT);
  82   bool Close();  // Close is a NOP if not opened
  83
  84   // assign an existing file descriptor and get it back from wxFile object
  85   void Attach(int fd) { Close(); m_fd = fd; }
  86   void Detach()       { m_fd = fd_invalid;  }
  87   int  fd() const { return m_fd; }
  88
  89   // read/write (unbuffered)
  90     // returns number of bytes read or ofsInvalid on error
  91   off_t Read(void *pBuf, off_t nCount);
  92     // returns true on success
  93   uint Write(const void *pBuf, uint nCount);
  94     // returns true on success
  95   bool Write(const wxString& s) { return Write(s.c_str(), s.Len()) != 0; }
  96     // flush data not yet written
  97   bool Flush();
  98
  99   // file pointer operations (return ofsInvalid on failure)
 100     // move ptr ofs bytes related to start/current off_t/end of file
 101   off_t Seek(off_t ofs, wxSeekMode mode = wxFromStart);
 102     // move ptr to ofs bytes before the end
 103   off_t SeekEnd(off_t ofs = 0) { return Seek(ofs, wxFromEnd); }
 104     // get current off_t
 105   off_t Tell() const;
 106     // get current file length
 107   off_t Length() const;
 108
 109   // simple accessors
 110     // is file opened?
 111   bool IsOpened() const { return m_fd != fd_invalid; }
 112     // is end of file reached?
 113   bool Eof() const;
 114     // is an error occured?
 115   bool Error() const { return m_error; }
 116
 117   // dtor closes the file if opened
 118   virtual ~wxFile(); // Temporally virtual because of wxFileStream: I'll change back in a near future.
 119
 120 private:
 121   // copy ctor and assignment operator are private because
 122   // it doesn't make sense to copy files this way:
 123   // attempt to do it will provoke a compile-time error.
 124   wxFile(const wxFile&);
 125   wxFile& operator=(const wxFile&);
 126
 127   int m_fd; // file descriptor or INVALID_FD if not opened
 128   bool m_error; // error memory
 129 };
 130
 131 // ----------------------------------------------------------------------------
 132 // class wxTempFile: if you want to replace another file, create an instance
 133 // of wxTempFile passing the name of the file to be replaced to the ctor. Then
 134 // you can write to wxTempFile and call Commit() function to replace the old
 135 // file (and close this one) or call Discard() to cancel the modification. If
 136 // you call neither of them, dtor will call Discard().
 137 // ----------------------------------------------------------------------------
 138 class WXDLLEXPORT wxTempFile
 139 {
 140 public:
 141   // ctors
 142     // default
 143   wxTempFile() { }
 144     // associates the temp file with the file to be replaced and opens it
 145   wxTempFile(const wxString& strName);
 146
 147   // open the temp file (strName is the name of file to be replaced)
 148   bool Open(const wxString& strName);
 149
 150   // is the file opened?
 151   bool IsOpened() const { return m_file.IsOpened(); }
 152
 153   // I/O (both functions return true on success, false on failure)
 154   bool Write(const void *p, uint n) { return m_file.Write(p, n) != 0; }
 155   bool Write(const wxString& str)   { return m_file.Write(str); }
 156
 157   // different ways to close the file
 158     // validate changes and delete the old file of name m_strName
 159   bool Commit();
 160     // discard changes
 161   void Discard();
 162
 163   // dtor calls Discard() if file is still opened
 164  ~wxTempFile();
 165
 166 private:
 167   wxString  m_strName,  // name of the file to replace in Commit()
 168             m_strTemp;  // temporary file name
 169   wxFile    m_file;     // the temporary file
 170 };
 171
 172 #endif
 173         // __FILEH__