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