pysize/core/history.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) 2006 Guillaume Chazarain <guichaz@yahoo.fr>
  18
  19 from pysize.core.pysize_fs_tree import pysize_tree
  20 from pysize.core.observable import observable
  21
  22 # [(fullpaths, name)]
  23 history = []
  24 next_insertion_index = 0
  25 history_observable = observable()
  26
  27 def add_entry(tree):
  28     global next_insertion_index
  29     fp = tree.fullpaths
  30     if not fp:
  31         return
  32     same = next_insertion_index and fp == history[next_insertion_index - 1][0]
  33     if not same:
  34         if next_insertion_index == len(history):
  35             # History is being written
  36             history.append(None)
  37         else:
  38             paths, name = history[next_insertion_index]
  39             if fp != paths:
  40                 # History took another path, clear the remaining forward history
  41                 del history[next_insertion_index + 1:]
  42         history[next_insertion_index] = fp, tree.root.get_name()
  43         next_insertion_index += 1
  44         history_observable.fire_observers(next_insertion_index, history)
  45
  46 def go_to_history(index):
  47     global next_insertion_index
  48     entry = history[index][0]
  49     next_insertion_index = index + 1
  50     history_observable.fire_observers(next_insertion_index, history)
  51     return entry
  52
  53 def forward():
  54     if len(history) > next_insertion_index:
  55         return go_to_history(next_insertion_index)
  56
  57 def back():
  58     if next_insertion_index > 1:
  59         return go_to_history(next_insertion_index - 2)