raw_display.py

Urwid is a Python library for making text console applications. It has many features including fluid

#!/usr/bin/python
#
# Urwid raw display module
#    Copyright (C) 2004-2007  Ian Ward
#
#    This library is free software; you can redistribute it and/or
#    modify it under the terms of the GNU Lesser General Public
#    License as published by the Free Software Foundation; either
#    version 2.1 of the License, or (at your option) any later version.
#
#    This library is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
#    Lesser General Public License for more details.
#
#    You should have received a copy of the GNU Lesser General Public
#    License along with this library; if not, write to the Free Software
#    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
# Urwid web site: http://excess.org/urwid/

"""
Direct terminal UI implementation
"""

import fcntl
import termios
import os
import select
import struct
import sys
import tty
import signal
import popen2

import util
import escape


# replace control characters with ?'s
_trans_table = "?"*32+"".join([chr(x) for x in range(32,256)])


class Screen(object):
	def __init__(self):
		self.palette = {}
		self.register_palette_entry( None, 'default','default')
		self.has_color = True # FIXME: detect this
		self._keyqueue = []
		self.prev_input_resize = 0
		self.set_input_timeouts()
		self.screen_buf = None
		self.resized = False
		self.maxrow = None
		self.gpm_mev = None
		self.gpm_event_pending = False
		self.last_bstate = 0
		self.setup_G1 = True
		self._started = False
	
	def register_palette( self, l ):
		"""Register a list of palette entries.

		l -- list of (name, foreground, background, mono),
		     (name, foreground, background) or
		     (name, same_as_other_name) palette entries.

		calls self.register_palette_entry for each item in l
		"""
		
		for item in l:
			if len(item) in (3,4):
				self.register_palette_entry( *item )
				continue
			assert len(item) == 2, "Invalid register_palette usage"
			name, like_name = item
			if not self.palette.has_key(like_name):
				raise Exception("palette entry '%s' doesn't exist"%like_name)
			self.palette[name] = self.palette[like_name]

	def register_palette_entry( self, name, foreground, background,
		mono=None):
		"""Register a single palette entry.

		name -- new entry/attribute name
		foreground -- foreground colour, one of: 'black', 'dark red',
			'dark green', 'brown', 'dark blue', 'dark magenta',
			'dark cyan', 'light gray', 'dark gray', 'light red',
			'light green', 'yellow', 'light blue', 'light magenta',
			'light cyan', 'white', 'default' (black if unable to
			use terminal's default)
		background -- background colour, one of: 'black', 'dark red',
			'dark green', 'brown', 'dark blue', 'dark magenta',
			'dark cyan', 'light gray', 'default' (light gray if
			unable to use terminal's default)
		mono -- monochrome terminal attribute, one of: None (default),
			'bold',	'underline', 'standout', or a tuple containing
			a combination eg. ('bold','underline')
			
		"""
		assert (mono is None or 
			mono in (None, 'bold', 'underline', 'standout') or
			type(mono)==type(()))
		
		self.palette[name] = (escape.set_attributes(
			foreground, background), mono)

	def set_input_timeouts(self, max_wait=0.5, complete_wait=0.1, 
		resize_wait=0.1):
		"""
		Set the get_input timeout values.  All values have are floating
		point number of seconds.
		
		max_wait -- amount of time in seconds to wait for input when
			there is no input pending
		complete_wait -- amount of time in seconds to wait when
			get_input detects an incomplete escape sequence at the
			end of the available input
		resize_wait -- amount of time in seconds to wait for more input
			after receiving two screen resize requests in a row to
			stop Urwid from consuming 100% cpu during a gradual
			window resize operation
		"""
		self.max_wait = max_wait
		self.complete_wait = complete_wait
		self.resize_wait = resize_wait

	def _sigwinch_handler(self, signum, frame):
		self.resized = True
		self.screen_buf = None
      
	def signal_init(self):
		"""
		Called in the startup of run wrapper to set the SIGWINCH 
		signal handler to self._sigwinch_handler.

		Override this function to call from main thread in threaded
		applications.
		"""
		signal.signal(signal.SIGWINCH, self._sigwinch_handler)
	
	def signal_restore(self):
		"""
		Called in the finally block of run wrapper to restore the
		SIGWINCH handler to the default handler.

		Override this function to call from main thread in threaded
		applications.
		"""
		signal.signal(signal.SIGWINCH, signal.SIG_DFL)
      
	def set_mouse_tracking(self):
		"""
		Enable mouse tracking.  
		
		After calling this function get_input will include mouse
		click events along with keystrokes.
		"""
		sys.stdout.write(escape.MOUSE_TRACKING_ON)

		self._start_gpm_tracking()
	
	def _start_gpm_tracking(self):
		if not os.path.isfile("/usr/bin/mev"):
			return
		if not os.environ.get('TERM',"").lower().startswith("linux"):
			return
		m = popen2.Popen3("/usr/bin/mev -e 158")
		self.gpm_mev = m
	
	def _stop_gpm_tracking(self):
		os.kill(self.gpm_mev.pid, signal.SIGINT)
		os.waitpid(self.gpm_mev.pid, 0)
		self.gpm_mev = None
	
	def start(self, alternate_buffer=True):
		"""
		Initialize the screen and input mode.
		
		alternate_buffer -- use alternate screen buffer
		"""
		assert not self._started
		if alternate_buffer:
			sys.stdout.write(escape.SWITCH_TO_ALTERNATE_BUFFER)
		self._old_termios_settings = termios.tcgetattr(0)
		self.signal_init()
		tty.setcbreak(sys.stdin.fileno())
		self._alternate_buffer = alternate_buffer
		self._input_iter = self._run_input_iter()
		self._next_timeout = self.max_wait
		self._started = True

	
	def stop(self):
		"""
		Restore the screen.
		"""
		self.clear()
		if not self._started:
			return
		self.signal_restore()
		termios.tcsetattr(0, termios.TCSADRAIN, 
			self._old_termios_settings)
		move_cursor = ""
		if self.gpm_mev:
			self._stop_gpm_tracking()
		if self._alternate_buffer:
			move_cursor = escape.RESTORE_NORMAL_BUFFER
		elif self.maxrow is not None:
			move_cursor = escape.set_cursor_position( 
				0, self.maxrow)
		sys.stdout.write( escape.set_attributes( 
			'default', 'default') 
			+ escape.SI
			+ escape.SHOW_CURSOR
			+ escape.MOUSE_TRACKING_OFF
			+ move_cursor + "\n" + escape.SHOW_CURSOR )
		self._input_iter = None
		self._started = False

	def run_wrapper(self, fn, alternate_buffer=True):
		"""
		Call start to initialize screen, then call fn.  
		When fn exits call stop to restore the screen to normal.

		alternate_buffer -- use alternate screen buffer and restore
			normal screen buffer on exit
		"""
		try:
			self.start(alternate_buffer)
			return fn()
		finally:
			self.stop()
			
	def get_input(self, raw_keys=False):
		"""Return pending input as a list.

		raw_keys -- return raw keycodes as well as translated versions

		This function will immediately return all the input since the
		last time it was called.  If there is no input pending it will
		wait before returning an empty list.  The wait time may be
		configured with the set_input_timeouts function.

		If raw_keys is False (default) this function will return a list
		of keys pressed.  If raw_keys is True this function will return
		a ( keys pressed, raw keycodes ) tuple instead.
		
		Examples of keys returned
		-------------------------
		ASCII printable characters:  " ", "a", "0", "A", "-", "/" 
		ASCII control characters:  "tab", "enter"
		Escape sequences:  "up", "page up", "home", "insert", "f1"
		Key combinations:  "shift f1", "meta a", "ctrl b"
		Window events:  "window resize"
		
		When a narrow encoding is not enabled
		"Extended ASCII" characters:  "\\xa1", "\\xb2", "\\xfe"

		When a wide encoding is enabled
		Double-byte characters:  "\\xa1\\xea", "\\xb2\\xd4"

		When utf8 encoding is enabled
		Unicode characters: u"\\u00a5", u'\\u253c"
		
		Examples of mouse events returned
		---------------------------------
		Mouse button press: ('mouse press', 1, 15, 13), 
		                    ('meta mouse press', 2, 17, 23)
		Mouse drag: ('mouse drag', 1, 16, 13),
		            ('mouse drag', 1, 17, 13),
			    ('ctrl mouse drag', 1, 18, 13)
		Mouse button release: ('mouse release', 0, 18, 13),
		                      ('ctrl mouse release', 0, 17, 23)
		"""
		assert self._started
		
		self._wait_for_input_ready(self._next_timeout)
		self._next_timeout, keys, raw = self._input_iter.next()
		
		# Avoid pegging CPU at 100% when slowly resizing
		if keys==['window resize'] and self.prev_input_resize:
			while True:
				self._wait_for_input_ready(self.resize_wait)
				self._next_timeout, keys, raw2 = \
					self._input_iter.next()
				raw += raw2
				#if not keys:
				#	keys, raw2 = self._get_input( 
				#		self.resize_wait)
				#	raw += raw2
				if keys!=['window resize']:
					break
			if keys[-1:]!=['window resize']:
				keys.append('window resize')
				
		if keys==['window resize']:
			self.prev_input_resize = 2
		elif self.prev_input_resize == 2 and not keys:
			self.prev_input_resize = 1
		else:
			self.prev_input_resize = 0
		
		if raw_keys:
			return keys, raw
		return keys

	def get_input_descriptors(self):
		"""
		Return a list of integer file descriptors that should be
		polled in external event loops to check for user input.

		Use this method if you are implementing yout own event loop.
		"""
		fd_list = [sys.stdin.fileno()]
		if self.gpm_mev is not None:
			fd_list.append(self.gpm_mev.fromchild.fileno())
		return fd_list
		
	def get_input_nonblocking(self):
		"""