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      1 # Copyright 2016 The Chromium OS Authors. All rights reserved.
      2 # Use of this source code is governed by a BSD-style license that can be
      3 # found in the LICENSE file.
      4 
      5 """Sequenced feedback request."""
      6 
      7 from __future__ import print_function
      8 
      9 import input_handlers
     10 import request
     11 import textwrap
     12 
     13 
     14 class _RequestAction(object):
     15     """An interface of a single action in a sequenced feedback request."""
     16 
     17     def execute(self):
     18         """Performs the action."""
     19         raise NotImplementedError
     20 
     21 
     22 class _QuestionRequestAction(_RequestAction):
     23     """A question to be presented to a user."""
     24 
     25     def __init__(self, blurb, input_handler, prompt=None):
     26         self.input_handler = input_handler
     27         blurb_supp, prompt_supp = input_handler.get_choices_supplements()
     28 
     29         # Initialize the question blurb string.
     30         self.blurb = self._format_text(blurb)
     31         if blurb_supp:
     32             self.blurb += '\n' + blurb_supp
     33 
     34         # Initialize the input prompt string.
     35         if prompt is None:
     36             prompt = ''
     37         if prompt_supp:
     38             if prompt:
     39                 prompt += ' '
     40             prompt += prompt_supp
     41         self.prompt = self._format_text(prompt)
     42         if self.prompt:
     43             self.prompt += ' '
     44 
     45     def _format_text(self, text):
     46         """Formats a blob of text for writing to standard output."""
     47         return textwrap.fill(text.strip())
     48 
     49 
     50     def execute(self):
     51         if self.blurb:
     52             print(self.blurb, end=('\n' if self.prompt else ' '))
     53         while True:
     54             try:
     55                 return self.input_handler.process(raw_input(self.prompt))
     56             except input_handlers.InputError:
     57                 print('Invalid input, try again')
     58 
     59 
     60 class SequencedFeedbackRequest(request.FeedbackRequest):
     61     """A request consisting of a sequence of interactive actions."""
     62 
     63     def __init__(self, *args):
     64         super(SequencedFeedbackRequest, self).__init__(*args)
     65         self._actions = []
     66 
     67 
     68     def _append_action(self, action):
     69         self._actions.append(action)
     70 
     71 
     72     def append_question(self, blurb, input_handler, prompt=None):
     73         """Appends a question to the request sequence.
     74 
     75         @param blurb: The text to print prior to asking for input.
     76         @param input_handler: The input handler object.
     77         @param prompt: String to print when polling for input.
     78         """
     79         attrs = {'test': self.test, 'dut': self.dut}
     80         blurb = blurb or ''
     81         self._append_action(_QuestionRequestAction(
     82                 blurb % attrs, input_handler,
     83                 prompt=(prompt and prompt % attrs)))
     84 
     85 
     86     def execute(self):
     87         """Executes the sequence of request actions.
     88 
     89         @return: The return value of the last action.
     90 
     91         @raise request.FeedbackRequestError: Failed during sequence execution.
     92         """
     93         ret = None
     94         for action in self._actions:
     95             ret = action.execute()
     96         return ret
     97