"Fossies" - the Fresh Open Source Software Archive

Member "polysh-polysh-0.13/polysh/display_names.py" (11 May 2020, 4047 Bytes) of package /linux/privat/polysh-polysh-0.13.tar.gz:

    1 """Polysh - Displaying Names
    2 
    3 Copyright (c) 2006 Guillaume Chazarain <guichaz@gmail.com>
    4 Copyright (c) 2018 InnoGames GmbH
    5 """
    6 # This program is free software: you can redistribute it and/or modify
    7 # it under the terms of the GNU General Public License as published by
    8 # the Free Software Foundation, either version 2 of the License, or
    9 # (at your option) any later version.
   10 #
   11 # This program is distributed in the hope that it will be useful,
   12 # but WITHOUT ANY WARRANTY; without even the implied warranty of
   13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   14 # GNU General Public License for more details.
   15 #
   16 # You should have received a copy of the GNU General Public License
   17 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
   18 
   19 from typing import Dict, List, Optional
   20 from collections import defaultdict
   21 # The prefix is the key, the value is a list of booleans. A boolean at an
   22 # index is True if that index is currently in use.
   23 PREFIXES = defaultdict(lambda: [])  # type: Dict[str, List[bool]]
   24 
   25 # dict with key:len(display_name) value:nr of enabled shells with a
   26 # display_name of such a length
   27 NR_ENABLED_DISPLAY_NAMES_BY_LENGTH = dict()  # type: Dict[int, int]
   28 
   29 # Used for terminal size and layout
   30 max_display_name_length = 0
   31 
   32 
   33 def acquire_prefix_index(prefix: str) -> int:
   34     # Search and reuse removed host suffix
   35     for idx, item in enumerate(PREFIXES[prefix]):
   36         if not item:
   37             PREFIXES[prefix][idx] = True
   38             return idx
   39 
   40     # Add new suffix if no old suffix can be reused
   41     PREFIXES[prefix].append(True)
   42     return len(PREFIXES[prefix]) - 1
   43 
   44 
   45 def release_prefix_index(prev_display_name: str) -> None:
   46     split = prev_display_name.split('#', 1)
   47     prefix = split[0]
   48     if len(split) == 1:
   49         suffix = 0
   50     else:
   51         suffix = int(split[1])
   52 
   53     # We are not deleting the host with the highest suffix. Therefore we need
   54     # to mark the current suffix index as unused.
   55     if suffix < len(PREFIXES[prefix]) - 1:
   56         PREFIXES[prefix][suffix] = False
   57         return None
   58 
   59     # We are deleting the host with the highest suffix. Therefore we need to
   60     # delete it.
   61     del PREFIXES[prefix][suffix]
   62 
   63     # Remove holes previously left.
   64     for idx, in_use in reversed(list(enumerate(PREFIXES[prefix]))):
   65         if in_use:
   66             return None
   67         del PREFIXES[prefix][idx]
   68 
   69     # If we arrived here, we just deleted the last item with a specific
   70     # prefix. Therefore we need to delete the whole prefix now.
   71     del PREFIXES[prefix]
   72 
   73 
   74 def make_unique_name(prefix: str) -> str:
   75     suffix = acquire_prefix_index(prefix)
   76     if suffix:
   77         return '{}#{}'.format(prefix, suffix)
   78 
   79     return prefix
   80 
   81 
   82 def update_max_display_name_length() -> None:
   83     from polysh.dispatchers import update_terminal_size
   84     new_max = max(NR_ENABLED_DISPLAY_NAMES_BY_LENGTH.keys(), default=0)
   85     global max_display_name_length
   86     if new_max != max_display_name_length:
   87         max_display_name_length = new_max
   88         update_terminal_size()
   89 
   90 
   91 def change(
   92     prev_display_name: Optional[str],
   93     new_prefix: Optional[str]
   94 ) -> Optional[str]:
   95     if new_prefix and '#' in new_prefix:
   96         raise Exception('Names cannot contain #')
   97 
   98     if prev_display_name is not None:
   99         if new_prefix is not None:
  100             set_enabled(prev_display_name, False)
  101         release_prefix_index(prev_display_name)
  102         if new_prefix is None:
  103             return None
  104 
  105     name = make_unique_name(new_prefix)
  106     set_enabled(name, True)
  107 
  108     return name
  109 
  110 
  111 def set_enabled(display_name: str, enabled: bool) -> None:
  112     length = len(display_name)
  113     if enabled:
  114         if length in NR_ENABLED_DISPLAY_NAMES_BY_LENGTH:
  115             NR_ENABLED_DISPLAY_NAMES_BY_LENGTH[length] += 1
  116         else:
  117             NR_ENABLED_DISPLAY_NAMES_BY_LENGTH[length] = 1
  118     else:
  119         NR_ENABLED_DISPLAY_NAMES_BY_LENGTH[length] -= 1
  120         if not NR_ENABLED_DISPLAY_NAMES_BY_LENGTH[length]:
  121             del NR_ENABLED_DISPLAY_NAMES_BY_LENGTH[length]
  122 
  123     update_max_display_name_length()