pmbootstrap/pmb/helpers/cli.py

96 lines
3.1 KiB
Python

# Copyright 2020 Oliver Smith
# SPDX-License-Identifier: GPL-3.0-or-later
import datetime
import logging
import re
import readline
class ReadlineTabCompleter:
""" Stores intermediate state for completer function """
def __init__(self, options):
"""
:param options: list of possible completions
"""
self.options = sorted(options)
self.matches = []
def completer_func(self, input_text, iteration):
"""
:param input_text: text that shall be autocompleted
:param iteration: how many times "tab" was hit
"""
# First time: build match list
if iteration == 0:
if input_text:
self.matches = [s for s in self.options if s and s.startswith(input_text)]
else:
self.matches = self.options[:]
# Return the N'th item from the match list, if we have that many.
if iteration < len(self.matches):
return self.matches[iteration]
return None
def ask(args, question="Continue?", choices=["y", "n"], default="n",
lowercase_answer=True, validation_regex=None, complete=None):
"""
Ask a question on the terminal.
:param question: display prompt
:param choices: short list of possible answers, displayed after prompt if set
:param default: default value to return if user doesn't input anything
:param lowercase_answer: if True, convert return value to lower case
:param validation_regex: if set, keep asking until regex matches
:param complete: set to a list to enable tab completion
"""
while True:
date = datetime.datetime.now().strftime("%H:%M:%S")
question_full = "[" + date + "] " + question
if choices:
question_full += " (" + str.join("/", choices) + ")"
if default:
question_full += " [" + str(default) + "]"
if complete:
readline.parse_and_bind('tab: complete')
readline.set_completer(ReadlineTabCompleter(complete).completer_func)
ret = input(question_full + ": ")
# Stop completing (question is answered)
if complete:
readline.set_completer(None)
if lowercase_answer:
ret = ret.lower()
if ret == "":
ret = str(default)
args.logfd.write(question_full + " " + ret + "\n")
args.logfd.flush()
# Validate with regex
if not validation_regex:
return ret
pattern = re.compile(validation_regex)
if pattern.match(ret):
return ret
logging.fatal("ERROR: Input did not pass validation (regex: " +
validation_regex + "). Please try again.")
def confirm(args, question="Continue?", default=False):
"""
Convenience wrapper around ask for simple yes-no questions with validation.
:returns: True for "y", False for "n"
"""
default_str = "y" if default else "n"
if (args.assume_yes):
logging.info(question + " (y/n) [" + default_str + "]: y")
return True
answer = ask(args, question, ["y", "n"], default_str, True, "(y|n)")
return answer == "y"