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 enum wxPosixPermissions
  31 {
  32     // standard Posix names for these permission flags:
  33     wxS_IRUSR = 00400,
  34     wxS_IWUSR = 00200,
  35     wxS_IXUSR = 00100,
  36
  37     wxS_IRGRP = 00040,
  38     wxS_IWGRP = 00020,
  39     wxS_IXGRP = 00010,
  40
  41     wxS_IROTH = 00004,
  42     wxS_IWOTH = 00002,
  43     wxS_IXOTH = 00001,
  44
  45     // longer but more readable synonims for the constants above:
  46     wxPOSIX_USER_READ = wxS_IRUSR,
  47     wxPOSIX_USER_WRITE = wxS_IWUSR,
  48     wxPOSIX_USER_EXECUTE = wxS_IXUSR,
  49
  50     wxPOSIX_GROUP_READ = wxS_IRGRP,
  51     wxPOSIX_GROUP_WRITE = wxS_IWGRP,
  52     wxPOSIX_GROUP_EXECUTE = wxS_IXGRP,
  53
  54     wxPOSIX_OTHERS_READ = wxS_IROTH,
  55     wxPOSIX_OTHERS_WRITE = wxS_IWOTH,
  56     wxPOSIX_OTHERS_EXECUTE = wxS_IXOTH,
  57
  58     // default mode for the new files: allow reading/writing them to everybody but
  59     // the effective file mode will be set after anding this value with umask and
  60     // so won't include wxS_IW{GRP,OTH} for the default 022 umask value
  61     wxS_DEFAULT = (wxPOSIX_USER_READ | wxPOSIX_USER_WRITE | \
  62                    wxPOSIX_GROUP_READ | wxPOSIX_GROUP_WRITE | \
  63                    wxPOSIX_OTHERS_READ | wxPOSIX_OTHERS_WRITE),
  64
  65     // default mode for the new directories (see wxFileName::Mkdir): allow
  66     // reading/writing/executing them to everybody, but just like wxS_DEFAULT
  67     // the effective directory mode will be set after anding this value with umask
  68     wxS_DIR_DEFAULT = (wxPOSIX_USER_READ | wxPOSIX_USER_WRITE | wxPOSIX_USER_EXECUTE | \
  69                        wxPOSIX_GROUP_READ | wxPOSIX_GROUP_WRITE | wxPOSIX_GROUP_EXECUTE | \
  70                        wxPOSIX_OTHERS_READ | wxPOSIX_OTHERS_WRITE | wxPOSIX_OTHERS_EXECUTE)
  71 };
  72
  73 // ----------------------------------------------------------------------------
  74 // class wxFile: raw file IO
  75 //
  76 // NB: for space efficiency this class has no virtual functions, including
  77 //     dtor which is _not_ virtual, so it shouldn't be used as a base class.
  78 // ----------------------------------------------------------------------------
  79
  80 class WXDLLIMPEXP_BASE wxFile
  81 {
  82 public:
  83   // more file constants
  84   // -------------------
  85     // opening mode
  86   enum OpenMode { read, write, read_write, write_append, write_excl };
  87     // standard values for file descriptor
  88   enum { fd_invalid = -1, fd_stdin, fd_stdout, fd_stderr };
  89
  90   // static functions
  91   // ----------------
  92     // check whether a regular file by this name exists
  93   static bool Exists(const wxString& name);
  94     // check whether we can access the given file in given mode
  95     // (only read and write make sense here)
  96   static bool Access(const wxString& name, OpenMode mode);
  97
  98   // ctors
  99   // -----
 100     // def ctor
 101   wxFile() { m_fd = fd_invalid; m_error = false; }
 102     // open specified file (may fail, use IsOpened())
 103   wxFile(const wxString& fileName, OpenMode mode = read);
 104     // attach to (already opened) file
 105   wxFile(int lfd) { m_fd = lfd; m_error = false; }
 106
 107   // open/close
 108     // create a new file (with the default value of bOverwrite, it will fail if
 109     // the file already exists, otherwise it will overwrite it and succeed)
 110   bool Create(const wxString& fileName, bool bOverwrite = false,
 111               int access = wxS_DEFAULT);
 112   bool Open(const wxString& fileName, OpenMode mode = read,
 113             int access = wxS_DEFAULT);
 114   bool Close();  // Close is a NOP if not opened
 115
 116   // assign an existing file descriptor and get it back from wxFile object
 117   void Attach(int lfd) { Close(); m_fd = lfd; m_error = false; }
 118   void Detach()       { m_fd = fd_invalid;  }
 119   int  fd() const { return m_fd; }
 120
 121   // read/write (unbuffered)
 122     // returns number of bytes read or wxInvalidOffset on error
 123   ssize_t Read(void *pBuf, size_t nCount);
 124     // returns the number of bytes written
 125   size_t Write(const void *pBuf, size_t nCount);
 126     // returns true on success
 127   bool Write(const wxString& s, const wxMBConv& conv = wxMBConvUTF8());
 128     // flush data not yet written
 129   bool Flush();
 130
 131   // file pointer operations (return wxInvalidOffset on failure)
 132     // move ptr ofs bytes related to start/current offset/end of file
 133   wxFileOffset Seek(wxFileOffset ofs, wxSeekMode mode = wxFromStart);
 134     // move ptr to ofs bytes before the end
 135   wxFileOffset SeekEnd(wxFileOffset ofs = 0) { return Seek(ofs, wxFromEnd); }
 136     // get current offset
 137   wxFileOffset Tell() const;
 138     // get current file length
 139   wxFileOffset Length() const;
 140
 141   // simple accessors
 142     // is file opened?
 143   bool IsOpened() const { return m_fd != fd_invalid; }
 144     // is end of file reached?
 145   bool Eof() const;
 146     // has an error occurred?
 147   bool Error() const { return m_error; }
 148     // type such as disk or pipe
 149   wxFileKind GetKind() const { return wxGetFileKind(m_fd); }
 150
 151   // dtor closes the file if opened
 152   ~wxFile() { Close(); }
 153
 154 private:
 155   // copy ctor and assignment operator are private because
 156   // it doesn't make sense to copy files this way:
 157   // attempt to do it will provoke a compile-time error.
 158   wxFile(const wxFile&);
 159   wxFile& operator=(const wxFile&);
 160
 161   int m_fd; // file descriptor or INVALID_FD if not opened
 162   bool m_error; // error memory
 163 };
 164
 165 // ----------------------------------------------------------------------------
 166 // class wxTempFile: if you want to replace another file, create an instance
 167 // of wxTempFile passing the name of the file to be replaced to the ctor. Then
 168 // you can write to wxTempFile and call Commit() function to replace the old
 169 // file (and close this one) or call Discard() to cancel the modification. If
 170 // you call neither of them, dtor will call Discard().
 171 // ----------------------------------------------------------------------------
 172
 173 class WXDLLIMPEXP_BASE wxTempFile
 174 {
 175 public:
 176   // ctors
 177     // default
 178   wxTempFile() { }
 179     // associates the temp file with the file to be replaced and opens it
 180   wxTempFile(const wxString& strName);
 181
 182   // open the temp file (strName is the name of file to be replaced)
 183   bool Open(const wxString& strName);
 184
 185   // is the file opened?
 186   bool IsOpened() const { return m_file.IsOpened(); }
 187     // get current file length
 188   wxFileOffset Length() const { return m_file.Length(); }
 189     // move ptr ofs bytes related to start/current offset/end of file
 190   wxFileOffset Seek(wxFileOffset ofs, wxSeekMode mode = wxFromStart)
 191     { return m_file.Seek(ofs, mode); }
 192     // get current offset
 193   wxFileOffset Tell() const { return m_file.Tell(); }
 194
 195   // I/O (both functions return true on success, false on failure)
 196   bool Write(const void *p, size_t n) { return m_file.Write(p, n) == n; }
 197   bool Write(const wxString& str, const wxMBConv& conv = wxMBConvUTF8())
 198     { return m_file.Write(str, conv); }
 199
 200   // flush data: can be called before closing file to ensure that data was
 201   // correctly written out
 202   bool Flush() { return m_file.Flush(); }
 203
 204   // different ways to close the file
 205     // validate changes and delete the old file of name m_strName
 206   bool Commit();
 207     // discard changes
 208   void Discard();
 209
 210   // dtor calls Discard() if file is still opened
 211  ~wxTempFile();
 212
 213 private:
 214   // no copy ctor/assignment operator
 215   wxTempFile(const wxTempFile&);
 216   wxTempFile& operator=(const wxTempFile&);
 217
 218   wxString  m_strName,  // name of the file to replace in Commit()
 219             m_strTemp;  // temporary file name
 220   wxFile    m_file;     // the temporary file
 221 };
 222
 223 #endif // wxUSE_FILE
 224
 225 #endif // _WX_FILEH__