scripts/release/io.py

   1 #!/usr/bin/python2.5
   2 #
   3 # Copyright 2009 the Melange authors.
   4 #
   5 # Licensed under the Apache License, Version 2.0 (the "License");
   6 # you may not use this file except in compliance with the License.
   7 # You may obtain a copy of the License at
   8 #
   9 #   http://www.apache.org/licenses/LICENSE-2.0
  10 #
  11 # Unless required by applicable law or agreed to in writing, software
  12 # distributed under the License is distributed on an "AS IS" BASIS,
  13 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14 # See the License for the specific language governing permissions and
  15 # limitations under the License.
  16
  17 from __future__ import with_statement
  18
  19 """User prompting and file access utilities."""
  20
  21 __authors__ = [
  22     # alphabetical order by last name, please
  23     '"David Anderson" <dave@natulte.net>',
  24     ]
  25
  26 import error
  27 import log
  28
  29
  30 class Error(error.Error):
  31   pass
  32
  33
  34 class FileAccessError(Error):
  35   """An error occured while accessing a file."""
  36   pass
  37
  38
  39 def getString(prompt):
  40   """Prompt for and return a string."""
  41   prompt += ' '
  42   log.stdout.write(prompt)
  43   log.stdout.flush()
  44
  45   response = sys.stdin.readline()
  46   log.terminal_echo(prompt + response.strip())
  47   if not response:
  48     raise error.AbortedByUser('Aborted by ctrl+D')
  49
  50   return response.strip()
  51
  52
  53 def confirm(prompt, default=False):
  54   """Ask a yes/no question and return the answer.
  55
  56   Will reprompt the user until one of "yes", "no", "y" or "n" is
  57   entered. The input is case insensitive.
  58
  59   Args:
  60     prompt: The question to ask the user.
  61     default: The answer to return if the user just hits enter.
  62
  63   Returns:
  64     True if the user answered affirmatively, False otherwise.
  65   """
  66   if default:
  67     question = prompt + ' [Yn]'
  68   else:
  69     question = prompt + ' [yN]'
  70   while True:
  71     answer = getString(question)
  72     if not answer:
  73       return default
  74     elif answer in ('y', 'yes'):
  75       return True
  76     elif answer in ('n', 'no'):
  77       return False
  78     else:
  79       log.error('Please answer yes or no.')
  80
  81
  82 def getNumber(prompt):
  83   """Prompt for and return a number.
  84
  85   Will reprompt the user until a number is entered.
  86   """
  87   while True:
  88     value_str = getString(prompt)
  89     try:
  90       return int(value_str)
  91     except ValueError:
  92       log.error('Please enter a number. You entered "%s".' % value_str)
  93
  94
  95 def getChoice(intro, prompt, choices, done=None, suggest=None):
  96   """Prompt for and return a choice from a menu.
  97
  98   Will reprompt the user until a valid menu entry is chosen.
  99
 100   Args:
 101     intro: Text to print verbatim before the choice menu.
 102     prompt: The prompt to print right before accepting input.
 103     choices: The list of string choices to display.
 104     done: If not None, the list of indices of previously
 105       selected/completed choices.
 106     suggest: If not None, the index of the choice to highlight as
 107       the suggested choice.
 108
 109   Returns:
 110     The index in the choices list of the selection the user made.
 111   """
 112   done = set(done or [])
 113   while True:
 114     print intro
 115     print
 116     for i, entry in enumerate(choices):
 117       done_text = ' (done)' if i in done else ''
 118       indent = '--> ' if i == suggest else '    '
 119       print '%s%2d. %s%s' % (indent, i+1, entry, done_text)
 120     print
 121     choice = getNumber(prompt)
 122     if 0 < choice <= len(choices):
 123       return choice-1
 124     log.error('%d is not a valid choice between %d and %d' %
 125               (choice, 1, len(choices)))
 126     print
 127
 128
 129 def fileToLines(path):
 130   """Read a file and return it as a list of lines."""
 131   try:
 132     with file(path) as f:
 133       return f.read().split('\n')
 134   except (IOError, OSError), e:
 135     raise FileAccessError(str(e))
 136
 137
 138 def linesToFile(path, lines):
 139   """Write a list of lines to a file."""
 140   try:
 141     with file(path, 'w') as f:
 142       f.write('\n'.join(lines))
 143   except (IOError, OSError), e:
 144     raise FileAccessError(str(e))