pidcat prints nothing when run through emacs

[olegat]

pidcat do not show anything if it's run through the emacs Terminal emulator.

Steps to reproduce:

• Install Emacs and pidcat
• Open up a terminal
• Run emacs
• Hit M-x (Alt+x)
• Type shell and hit ENTER
• Type pidcat.py and hit ENTER

Notes:

• You can kill the python process by hitting C-c C-c (Control+C, Control+C)
• You should see that the script is stuck in a loop in indent_wrap
• To exit emacs, hit C-x C-c (Control+X, followed by Control+C). You may need to type yes if you're prompted to kill the active shell process

def indent_wrap(message):
  if width == -1:
    return message
  message = message.replace('\t', '    ')
  wrap_area = width - header_size
  messagebuf = ''
  current = 0
  while current < len(message):
    next = min(current + wrap_area, len(message))
    messagebuf += message[current:next]
    if next < len(message):
      messagebuf += '\n'
      messagebuf += ' ' * header_size
    current = next
  return messagebuf

The script is looping because width is 0, this causes wrap_area = width - header_size to produce a negative number, which causes next = min(current + wrap_area, len(message)) to continuously decrease in every loop iteration because the left-hand parameter of min is always negative.

There's a workaround that involves tweaking the initialisation of width:

width = -1
try:
  # Get the current terminal width                                                                                                              
  import fcntl, termios, struct
  h, width = struct.unpack('hh', fcntl.ioctl(0, termios.TIOCGWINSZ, struct.pack('hh', 0, 0)))
  # ioctl may occasionally return 0 (example, in emacs terminal)                                                                                
  if width <= 0:
    width = -1
except:
  pass