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# Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
import sys
from chromite.lib import terminal
# Output verbosity levels that we support
ERROR = 0
WARNING = 1
NOTICE = 2
INFO = 3
DEBUG = 4
class Output:
"""Output class for Chrome OS.
This class handles output of progress and other useful information
to the user. It provides for simple verbosity level control and can
output nothing but errors at verbosity zero.
The idea is that modules set up an Output object early in their years and pass
it around to other modules that need it. This keeps the output under control
of a single class.
TODO(sjg): Merge / join with Chromite libraries
Public properties:
verbose: Verbosity level: 0=silent, 1=progress, 3=full, 4=debug
"""
def __init__(self, verbose=WARNING, stdout=sys.stdout):
"""Initialize a new output object.
Args:
verbose: Verbosity level (0-4).
stdout: File to use for stdout.
"""
self.verbose = verbose
self._progress = '' # Our last progress message
self._color = terminal.Color()
self._stdout = stdout
# TODO(sjg): Move this into Chromite libraries when we have them
self.stdout_is_tty = hasattr(sys.stdout, 'isatty') and sys.stdout.isatty()
def __enter__(self):
return self
def __exit__(self, unused1, unused2, unused3):
"""Clean up and remove any progress message."""
self.ClearProgress()
return False
def UserIsPresent(self):
"""This returns True if it is likely that a user is present.
Sometimes we want to prompt the user, but if no one is there then this
is a waste of time, and may lock a script which should otherwise fail.
Returns:
True if it thinks the user is there, and False otherwise
"""
return self.stdout_is_tty and self.verbose > 0
def ClearProgress(self):
"""Clear any active progress message on the terminal."""
if self.verbose > 0 and self.stdout_is_tty:
self._stdout.write('\r%s\r' % (" " * len (self._progress)))
self._stdout.flush()
def Progress(self, msg, warning=False, trailer='...'):
"""Display progress information.
Args:
msg: Message to display.
warning: True if this is a warning."""
self.ClearProgress()
if self.verbose > 0:
self._progress = msg + trailer
if self.stdout_is_tty:
col = self._color.YELLOW if warning else self._color.GREEN
self._stdout.write('\r' + self._color.Color(col, self._progress))
self._stdout.flush()
else:
self._stdout.write(self._progress + '\n')
def _Output(self, level, msg, color=None):
"""Output a message to the terminal.
Args:
level: Verbosity level for this message. It will only be displayed if
this as high as the currently selected level.
msg; Message to display.
error: True if this is an error message, else False.
"""
if self.verbose >= level:
self.ClearProgress()
if color:
msg = self._color.Color(color, msg)
self._stdout.write(msg + '\n')
def DoOutput(self, level, msg):
"""Output a message to the terminal.
Args:
level: Verbosity level for this message. It will only be displayed if
this as high as the currently selected level.
msg; Message to display.
"""
self._Output(level, msg)
def Error(self, msg):
"""Display an error message
Args:
msg; Message to display.
"""
self._Output(0, msg, self._color.RED)
def Warning(self, msg):
"""Display a warning message
Args:
msg; Message to display.
"""
self._Output(1, msg, self._color.YELLOW)
def Notice(self, msg):
"""Display an important infomation message
Args:
msg; Message to display.
"""
self._Output(2, msg)
def Info(self, msg):
"""Display an infomation message
Args:
msg; Message to display.
"""
self._Output(3, msg)
def Debug(self, msg):
"""Display a debug message
Args:
msg; Message to display.
"""
self._Output(4, msg)
def UserOutput(self, msg):
"""Display a message regardless of the current output level.
This is used when the output was specifically requested by the user.
Args:
msg; Message to display.
"""
self._Output(0, msg)