polysh/completion.py

   1 # This program is free software; you can redistribute it and/or modify
   2 # it under the terms of the GNU General Public License as published by
   3 # the Free Software Foundation; either version 2 of the License, or
   4 # (at your option) any later version.
   5 #
   6 # This program is distributed in the hope that it will be useful,
   7 # but WITHOUT ANY WARRANTY; without even the implied warranty of
   8 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   9 # GNU Library General Public License for more details.
  10 #
  11 # You should have received a copy of the GNU General Public License
  12 # along with this program; if not, write to the Free Software
  13 # Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  14 #
  15 # See the COPYING file for license information.
  16 #
  17 # Copyright (c) 2008 Guillaume Chazarain <guichaz@gmail.com>
  18
  19 import glob
  20 import os
  21 import readline
  22
  23 from polysh.control_commands_helpers import complete_control_command
  24 from polysh.control_commands_helpers import expand_local_path
  25
  26 def complete_local_path(path):
  27     def get_suffix(p):
  28         if os.path.isdir(p):
  29             return '/'
  30         return ''
  31     path = expand_local_path(path)
  32     paths = [p + get_suffix(p) for p in glob.glob(path + '*')]
  33     return paths
  34
  35 def remove_dupes(words):
  36     added = set()
  37     results = list()
  38     for w in words:
  39         stripped = w.rstrip('/ ')
  40         if stripped not in added:
  41             added.add(stripped)
  42             results.append(w)
  43     return results
  44
  45 def read_commands_in_path():
  46     commands = set()
  47
  48     for path in (os.getenv('PATH') or '').split(':'):
  49         if path:
  50             try:
  51                 listing = os.listdir(path)
  52             except OSError:
  53                 pass
  54             else:
  55                 commands |= set(listing)
  56     return list(commands)
  57
  58 # All the words that have been typed in polysh. Used by the completion
  59 # mechanism.
  60 history_words = set()
  61
  62 # When listing possible completions, the complete() function is called with
  63 # an increasing state parameter until it returns None. Cache the completion
  64 # list instead of regenerating it for each completion item.
  65 completion_results = None
  66
  67 # Commands in $PATH, used for the completion of the first word
  68 user_commands_in_path = read_commands_in_path()
  69
  70 try:
  71     import ctypes.util
  72     lib_readline = ctypes.cdll.LoadLibrary(ctypes.util.find_library("readline"))
  73     rl_completion_append_character = ctypes.c_char.in_dll(lib_readline,
  74                                                "rl_completion_append_character")
  75 except Exception:
  76     class rl_completion_append_character:
  77         pass
  78
  79
  80 def complete(text, state):
  81     """On tab press, return the next possible completion"""
  82     rl_completion_append_character.value = '\0'
  83     global completion_results
  84     if state == 0:
  85         line = readline.get_line_buffer()
  86         if line.startswith(':'):
  87             # Control command completion
  88             completion_results = complete_control_command(line, text)
  89         else:
  90             if line.startswith('!') and text and line.startswith(text):
  91                 dropped_exclam = True
  92                 text = text[1:]
  93             else:
  94                 dropped_exclam = False
  95             completion_results = []
  96             # Complete local paths
  97             completion_results += complete_local_path(text)
  98             # Complete from history
  99             l = len(text)
 100             completion_results += [w + ' ' for w in history_words if \
 101                                               len(w) > l and w.startswith(text)]
 102             if readline.get_begidx() == 0:
 103                 # Completing first word from $PATH
 104                 completion_results += [w + ' ' for w in user_commands_in_path \
 105                                            if len(w) > l and w.startswith(text)]
 106             completion_results = remove_dupes(completion_results)
 107             if dropped_exclam:
 108                 completion_results = ['!' + r for r in completion_results]
 109
 110     if state < len(completion_results):
 111         return completion_results[state]
 112     completion_results = None
 113
 114 def add_to_history(cmd):
 115     words = [w for w in cmd.split() if len(w) > 1]
 116     history_words.update(words)
 117     if len(history_words) > 10000:
 118         del history_words[:-10000]
 119
 120 def remove_last_history_item():
 121     """The user just typed a password..."""
 122     last = readline.get_current_history_length() - 1
 123     readline.remove_history_item(last)
 124
 125 def install_completion_handler():
 126     readline.set_completer(complete)
 127     readline.parse_and_bind('tab: complete')
 128     readline.set_completer_delims(' \t\n')
 129