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/filefn.h>
  25
  26 // define off_t
  27 #include  <sys/types.h>
  28
  29 #ifdef    _MSC_VER
  30   #define   off_t       _off_t
  31 #endif
  32
  33 // ----------------------------------------------------------------------------
  34 // constants
  35 // ----------------------------------------------------------------------------
  36
  37 // error return value for Seek() functions
  38 const off_t ofsInvalid = (off_t)-1;
  39
  40 // ----------------------------------------------------------------------------
  41 // class wxFile: raw file IO
  42 //
  43 // NB: for space efficiency this class has no virtual functions, including
  44 //     dtor which is _not_ virtual, so it shouldn't be used as a base class.
  45 // ----------------------------------------------------------------------------
  46 class WXDLLEXPORT wxFile
  47 {
  48 public:
  49   // more file constants
  50   // -------------------
  51
  52     // opening mode
  53   enum OpenMode { read, write, read_write, write_append };
  54     // standard values for file descriptor
  55   enum { fd_invalid = -1, fd_stdin, fd_stdout, fd_stderr };
  56     // seek type
  57   enum SeekMode { FromStart, FromEnd, FromCurrent };
  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   bool 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, SeekMode mode = FromStart);
  95     // move ptr to ofs bytes before the end
  96   off_t SeekEnd(off_t ofs = 0) { return Seek(ofs, FromEnd); }
  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
 108   // dtor closes the file if opened
 109  ~wxFile();
 110
 111 private:
 112   // copy ctor and assignment operator are private because
 113   // it doesn't make sense to copy files this way:
 114   // attempt to do it will provoke a compile-time error.
 115   wxFile(const wxFile&);
 116   wxFile& operator=(const wxFile&);
 117
 118   int m_fd; // file descriptor or INVALID_FD if not opened
 119 };
 120
 121 // ----------------------------------------------------------------------------
 122 // class wxTempFile: if you want to replace another file, create an instance
 123 // of wxTempFile passing the name of the file to be replaced to the ctor. Then
 124 // you can write to wxTempFile and call Commit() function to replace the old
 125 // file (and close this one) or call Discard() to cancel the modification. If
 126 // you call neither of them, dtor will call Discard().
 127 // ----------------------------------------------------------------------------
 128 class wxTempFile
 129 {
 130 public:
 131   // ctors
 132     // default
 133   wxTempFile() { }
 134     // associates the temp file with the file to be replaced and opens it
 135   wxTempFile(const wxString& strName);
 136
 137   // open the temp file (strName is the name of file to be replaced)
 138   bool Open(const wxString& strName);
 139
 140   // is the file opened?
 141   bool IsOpened() const { return m_file.IsOpened(); }
 142
 143   // I/O (both functions return true on success, false on failure)
 144   bool Write(const void *p, uint n) { return m_file.Write(p, n); }
 145   bool Write(const wxString& str)   { return m_file.Write(str);  }
 146
 147   // different ways to close the file
 148     // validate changes and delete the old file of name m_strName
 149   bool Commit();
 150     // discard changes
 151   void Discard();
 152
 153   // dtor calls Discard() if file is still opened
 154  ~wxTempFile();
 155
 156 private:
 157   wxString  m_strName,  // name of the file to replace in Commit()
 158             m_strTemp;  // temporary file name
 159   wxFile    m_file;     // the temporary file
 160 };
 161
 162 #endif
 163         // __FILEH__