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# Copyright (c) 2011 The Chromium OS Authors.
#
# See file CREDITS for list of people who contributed to this
# project.
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License as
# published by the Free Software Foundation; either version 2 of
# the License, or (at your option) any later version.
#
# This program 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston,
# MA 02111-1307 USA
#
"""Terminal utilities
This module handles terminal interaction including ANSI color codes.
"""
import os
import sys
# Selection of when we want our output to be colored
COLOR_IF_TERMINAL, COLOR_ALWAYS, COLOR_NEVER = range(3)
class Color(object):
"""Conditionally wraps text in ANSI color escape sequences."""
BLACK, RED, GREEN, YELLOW, BLUE, MAGENTA, CYAN, WHITE = range(8)
BOLD = -1
COLOR_START = '\033[1;%dm'
BOLD_START = '\033[1m'
RESET = '\033[0m'
def __init__(self, colored=COLOR_IF_TERMINAL):
"""Create a new Color object, optionally disabling color output.
Args:
enabled: True if color output should be enabled. If False then this
class will not add color codes at all.
"""
self._enabled = (colored == COLOR_ALWAYS or
(colored == COLOR_IF_TERMINAL and os.isatty(sys.stdout.fileno())))
def Start(self, color):
"""Returns a start color code.
Args:
color: Color to use, .e.g BLACK, RED, etc.
Returns:
If color is enabled, returns an ANSI sequence to start the given color,
otherwise returns empty string
"""
if self._enabled:
return self.COLOR_START % (color + 30)
return ''
def Stop(self):
"""Retruns a stop color code.
Returns:
If color is enabled, returns an ANSI color reset sequence, otherwise
returns empty string
"""
if self._enabled:
return self.RESET
return ''
def Color(self, color, text):
"""Returns text with conditionally added color escape sequences.
Keyword arguments:
color: Text color -- one of the color constants defined in this class.
text: The text to color.
Returns:
If self._enabled is False, returns the original text. If it's True,
returns text with color escape sequences based on the value of color.
"""
if not self._enabled:
return text
if color == self.BOLD:
start = self.BOLD_START
else:
start = self.COLOR_START % (color + 30)
return start + text + self.RESET
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