[Sommaire] [Imprimer]

   1  
   2  Patrick O'Lone suggests the following idea which sounds interesting to
   3  add as an optional mode of Cache_Lite class. 
   4  (still not tested in the Cache_Lite context)
   5  
   6  -------------------------------------------------------------------------
   7  If you use the flags:
   8  
   9  ignore_user_abort(true);
  10  
  11  $fd = dio_open($szFilename, O_CREATE | O_EXCL | O_TRUNC | O_WRONLY,
  12  0644);
  13  if (is_resource($fd)) {
  14  
  15     dio_fcntl($fd, F_SETLKW, array('type' => F_WRLCK));
  16     dio_write($fd, $szBuffer);
  17     dio_fcntl($fd, F_SETLK, array('type' => F_UNLCK));
  18     dio_close($fd);
  19  
  20  }
  21  
  22  ignore_user_abort(false);
  23  
  24  Only the first process will attempt to create a file. Additional
  25  processes will see that a file already exists (at the system level), and
  26  will fail. Another thing to note is that the file descriptor must be
  27  opened using dio_open(), and certain features, like fgets() won't work
  28  with it. If your just doing a raw write, dio_write() should be just
  29  fine. The dio_read() function should be used like:
  30  
  31  $fd = dio_open($szFilename, O_RDONLY|O_NONBLOCK, 0644);
  32  if (is_resource($fd)) {
  33  
  34     dio_fcntl($fd, F_SETLKW, array('type' => F_RDLCK));
  35     $szBuffer = dio_read($fd, filesize($szFilename));
  36     dio_fcntl($fd, F_SETLK, array('type' => F_UNLCK));
  37     dio_close($fd);
  38  
  39  }
  40  
  41  You still use locking to ensure that a write process can finish before
  42  another attempts to read the file. We also set non-blocking mode in read
  43  mode so that multiple readers can access the same resource at the same
  44  time. NOTE: Direct I/O support must be compiled into PHP for these
  45  features to work (--enable-dio).
  46  -------------------------------------------------------------------------