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# Copyright (C) 2005-2011 Canonical Ltd
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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"""Abstraction for interacting with the user.
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Applications can choose different types of UI, and they deal with displaying
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messages or progress to the user, and with gathering different types of input.
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Several levels are supported, and you can also register new factories such as
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Semi-abstract base class
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breezy.ui.SilentUIFactory
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Produces no output and cannot take any input; useful for programs using
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breezy in batch mode or for programs such as loggerhead.
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breezy.ui.CannedInputUIFactory
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For use in testing; the input values to be returned are provided
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breezy.ui.text.TextUIFactory
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Standard text command-line interface, with stdin, stdout, stderr.
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May make more or less advanced use of them, eg in drawing progress bars,
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depending on the detected capabilities of the terminal.
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GUIs may choose to subclass this so that unimplemented methods fall
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back to working through the terminal.
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from ..lazy_import import lazy_import
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lazy_import(globals(), """
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_valid_boolean_strings = dict(yes=True, no=False,
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true=True, false=False)
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_valid_boolean_strings['1'] = True
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_valid_boolean_strings['0'] = False
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def bool_from_string(s, accepted_values=None):
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"""Returns a boolean if the string can be interpreted as such.
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Interpret case insensitive strings as booleans. The default values
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includes: 'yes', 'no, 'y', 'n', 'true', 'false', '0', '1', 'on',
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'off'. Alternative values can be provided with the 'accepted_values'
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:param s: A string that should be interpreted as a boolean. It should be of
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type string or unicode.
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:param accepted_values: An optional dict with accepted strings as keys and
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True/False as values. The strings will be tested against a lowered
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:return: True or False for accepted strings, None otherwise.
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if accepted_values is None:
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accepted_values = _valid_boolean_strings
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if isinstance(s, str):
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val = accepted_values[s.lower()]
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class ConfirmationUserInterfacePolicy(object):
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"""Wrapper for a UIFactory that allows or denies all confirmed actions."""
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def __init__(self, wrapped_ui, default_answer, specific_answers):
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"""Generate a proxy UI that does no confirmations.
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:param wrapped_ui: Underlying UIFactory.
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:param default_answer: Bool for whether requests for
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confirmation from the user should be noninteractively accepted or
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:param specific_answers: Map from confirmation_id to bool answer.
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self.wrapped_ui = wrapped_ui
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self.default_answer = default_answer
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self.specific_answers = specific_answers
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def __getattr__(self, name):
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return getattr(self.wrapped_ui, name)
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return '%s(%r, %r, %r)' % (
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self.__class__.__name__,
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self.specific_answers)
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def confirm_action(self, prompt, confirmation_id, prompt_kwargs):
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if confirmation_id in self.specific_answers:
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return self.specific_answers[confirmation_id]
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elif self.default_answer is not None:
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return self.default_answer
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return self.wrapped_ui.confirm_action(
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prompt, confirmation_id, prompt_kwargs)
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class UIFactory(object):
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This tells the library how to display things to the user. Through this
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layer different applications can choose the style of UI.
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UI Factories are also context managers, for some syntactic sugar some users
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:ivar suppressed_warnings: Identifiers for user warnings that should
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_user_warning_templates = dict(
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cross_format_fetch=("Doing on-the-fly conversion from "
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"%(from_format)s to %(to_format)s.\n"
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"This may take some time. Upgrade the repositories to the "
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"same format for better performance."
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experimental_format_fetch=("Fetching into experimental format "
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"This format may be unreliable or change in the future "
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"without an upgrade path.\n"),
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"The command 'brz %(deprecated_name)s' "
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"has been deprecated in brz %(deprecated_in_version)s. "
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"Please use 'brz %(recommended_name)s' instead."),
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deprecated_command_option=(
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"The option '%(deprecated_name)s' to 'brz %(command)s' "
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"has been deprecated in brz %(deprecated_in_version)s. "
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"Please use '%(recommended_name)s' instead."),
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recommend_upgrade=("%(current_format_name)s is deprecated "
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"and a better format is available.\n"
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"It is recommended that you upgrade by "
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"running the command\n"
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" brz upgrade %(basedir)s"),
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u"Stole dead lock %(lock_url)s %(other_holder_info)s."),
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not_checking_ssl_cert=(
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u"Not checking SSL certificate for %(host)s."),
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self._task_stack = []
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self.suppressed_warnings = set()
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"""Context manager entry support.
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Override in a concrete factory class if initialisation before use is
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return self # This is bound to the 'as' clause in a with statement.
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def __exit__(self, exc_type, exc_val, exc_tb):
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"""Context manager exit support.
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Override in a concrete factory class if more cleanup than a simple
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self.clear_term() is needed when the UIFactory is finished with.
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return False # propogate exceptions.
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def be_quiet(self, state):
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"""Tell the UI to be more quiet, or not.
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Typically this suppresses progress bars; the application may also look
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at ui_factory.is_quiet().
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def confirm_action(self, prompt, confirmation_id, prompt_kwargs):
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"""Seek user confirmation for an action.
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If the UI is noninteractive, or the user does not want to be asked
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about this action, True is returned, indicating brz should just
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The confirmation id allows the user to configure certain actions to
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always be confirmed or always denied, and for UIs to specialize the
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display of particular confirmations.
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:param prompt: Suggested text to display to the user.
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:param prompt_kwargs: A dictionary of arguments that can be
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string-interpolated into the prompt.
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:param confirmation_id: Unique string identifier for the confirmation.
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return self.get_boolean(prompt % prompt_kwargs)
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def get_password(self, prompt=u'', **kwargs):
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"""Prompt the user for a password.
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:param prompt: The prompt to present the user (must be unicode)
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:param kwargs: Arguments which will be expanded into the prompt.
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This lets front ends display different things if
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:return: The password string, return None if the user canceled the
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request. Note that we do not touch the encoding, users may
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have whatever they see fit and the password should be
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raise NotImplementedError(self.get_password)
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def make_output_stream(self, encoding=None, encoding_type='replace'):
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"""Get a stream for sending out bulk text data.
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This is used for commands that produce bulk text, such as log or diff
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output, as opposed to user interaction. This should work even for
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non-interactive user interfaces. Typically this goes to a decorated
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version of stdout, but in a GUI it might be appropriate to send it to a
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window displaying the text.
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The caller may flush but should not close the returned stream.
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:param encoding: Unicode encoding for output; if not specified
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uses the configured 'output_encoding' if any; otherwise the
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(See get_terminal_encoding.)
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:param encoding_type: How to handle encoding errors:
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replace/strict/escape/exact. Default is replace.
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out_stream = self._make_output_stream_explicit(encoding, encoding_type)
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def _make_output_stream_explicit(self, encoding, encoding_type):
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raise NotImplementedError("%s doesn't support make_output_stream"
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% (self.__class__.__name__))
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def nested_progress_bar(self):
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"""Return a nested progress bar.
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When the bar has been finished with, it should be released by calling
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t = progress.ProgressTask(self._task_stack[-1], self)
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t = progress.ProgressTask(None, self)
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self._task_stack.append(t)
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def _progress_finished(self, task):
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"""Called by the ProgressTask when it finishes"""
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if not self._task_stack:
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warnings.warn("%r finished but nothing is active"
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if task in self._task_stack:
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self._task_stack.remove(task)
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warnings.warn("%r is not in active stack %r"
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% (task, self._task_stack))
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if not self._task_stack:
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self._progress_all_finished()
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def _progress_all_finished(self):
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"""Called when the top-level progress task finished"""
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def _progress_updated(self, task):
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"""Called by the ProgressTask when it changes.
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Should be specialized to draw the progress.
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def clear_term(self):
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"""Prepare the terminal for output.
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This will, for example, clear text progress bars, and leave the
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cursor at the leftmost position.
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def format_user_warning(self, warning_id, message_args):
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template = self._user_warning_templates[warning_id]
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fail = "brz warning: %r, %r" % (warning_id, message_args)
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warnings.warn("no template for warning: "
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+ fail) # so tests will fail etc
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return str(template) % message_args
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except ValueError as e:
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fail = "brz unprintable warning: %r, %r, %s" % (
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warning_id, message_args, e)
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warnings.warn(fail) # so tests will fail etc
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def choose(self, msg, choices, default=None):
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"""Prompt the user for a list of alternatives.
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:param msg: message to be shown as part of the prompt.
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:param choices: list of choices, with the individual choices separated
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by '\n', e.g.: choose("Save changes?", "&Yes\n&No\n&Cancel"). The
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letter after the '&' is the shortcut key for that choice. Thus you
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can type 'c' to select "Cancel". Shorcuts are case insensitive.
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The shortcut does not need to be the first letter. If a shorcut key
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is not provided, the first letter for the choice will be used.
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:param default: default choice (index), returned for example when enter
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is pressed for the console version.
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:return: the index fo the user choice (so '0', '1' or '2' for
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respectively yes/no/cancel in the previous example).
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raise NotImplementedError(self.choose)
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def get_boolean(self, prompt):
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"""Get a boolean question answered from the user.
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:param prompt: a message to prompt the user with. Should be a single
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line without terminating \\n.
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:return: True or False for y/yes or n/no.
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choice = self.choose(prompt + '?', '&yes\n&no', default=None)
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def get_integer(self, prompt):
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"""Get an integer from the user.
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:param prompt: a message to prompt the user with. Could be a multi-line
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prompt but without a terminating \\n.
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:return: A signed integer.
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raise NotImplementedError(self.get_integer)
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def make_progress_view(self):
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"""Construct a new ProgressView object for this UI.
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Application code should normally not call this but instead
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nested_progress_bar().
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return NullProgressView()
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def recommend_upgrade(self, current_format_name, basedir):
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"""Recommend the user upgrade a control directory.
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:param current_format_name: Description of the current format
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:param basedir: Location of the control dir
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self.show_user_warning('recommend_upgrade',
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current_format_name=current_format_name, basedir=basedir)
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def report_transport_activity(self, transport, byte_count, direction):
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"""Called by transports as they do IO.
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This may update a progress bar, spinner, or similar display.
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By default it does nothing.
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def log_transport_activity(self, display=False):
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"""Write out whatever transport activity has been measured.
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Implementations are allowed to do nothing, but it is useful if they can
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write a line to the log file.
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:param display: If False, only log to disk, if True also try to display
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a message to the user.
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# Default implementation just does nothing
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def show_user_warning(self, warning_id, **message_args):
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"""Show a warning to the user.
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This is specifically for things that are under the user's control (eg
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outdated formats), not for internal program warnings like deprecated
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This can be overridden by UIFactory subclasses to show it in some
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appropriate way; the default UIFactory is noninteractive and does
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nothing. format_user_warning maps it to a string, though other
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presentations can be used for particular UIs.
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:param warning_id: An identifier like 'cross_format_fetch' used to
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check if the message is suppressed and to look up the string.
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:param message_args: Arguments to be interpolated into the message.
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def show_error(self, msg):
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"""Show an error message (not an exception) to the user.
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The message should not have an error prefix or trailing newline. That
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will be added by the factory if appropriate.
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raise NotImplementedError(self.show_error)
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def show_message(self, msg):
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"""Show a message to the user."""
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raise NotImplementedError(self.show_message)
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def show_warning(self, msg):
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"""Show a warning to the user."""
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raise NotImplementedError(self.show_warning)
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class NoninteractiveUIFactory(UIFactory):
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"""Base class for UIs with no user."""
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def confirm_action(self, prompt, confirmation_id, prompt_kwargs):
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return '%s()' % (self.__class__.__name__, )
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class SilentUIFactory(NoninteractiveUIFactory):
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"""A UI Factory which never prints anything.
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This is the default UI, if another one is never registered by a program
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using breezy, and it's also active for example inside 'brz serve'.
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Methods that try to read from the user raise an error; methods that do
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UIFactory.__init__(self)
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def get_username(self, prompt, **kwargs):
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def _make_output_stream_explicit(self, encoding, encoding_type):
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return NullOutputStream(encoding)
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def show_error(self, msg):
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def show_message(self, msg):
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def show_warning(self, msg):
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class CannedInputUIFactory(SilentUIFactory):
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"""A silent UI that return canned input."""
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def __init__(self, responses):
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self.responses = responses
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return "%s(%r)" % (self.__class__.__name__, self.responses)
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def confirm_action(self, prompt, confirmation_id, args):
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return self.get_boolean(prompt % args)
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def get_boolean(self, prompt):
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return self.responses.pop(0)
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def get_integer(self, prompt):
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return self.responses.pop(0)
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def get_password(self, prompt=u'', **kwargs):
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return self.responses.pop(0)
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def get_username(self, prompt, **kwargs):
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return self.responses.pop(0)
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def assert_all_input_consumed(self):
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raise AssertionError("expected all input in %r to be consumed"
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ui_factory = SilentUIFactory()
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# IMPORTANT: never import this symbol directly. ONLY ever access it as
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# ui.ui_factory, so that you refer to the current value.
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def make_ui_for_terminal(stdin, stdout, stderr):
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"""Construct and return a suitable UIFactory for a text mode program.
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# this is now always TextUIFactory, which in turn decides whether it
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# should display progress bars etc
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from .text import TextUIFactory
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return TextUIFactory(stdin, stdout, stderr)
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class NullProgressView(object):
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"""Soak up and ignore progress information."""
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def show_progress(self, task):
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def show_transport_activity(self, transport, direction, byte_count):
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def log_transport_activity(self, display=False):
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class NullOutputStream(object):
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"""Acts like a file, but discard all output."""
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def __init__(self, encoding):
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self.encoding = encoding
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def write(self, data):
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def writelines(self, data):
added
removed
breezy/ui/__init__.py
