buffer.py

   1 import rox
   2 from rox import g
   3
   4 DELETE = 1
   5 INSERT = 2
   6
   7 class Buffer(g.TextBuffer):
   8         "A buffer that deals with undo/redo."
   9
  10         def __init__(self):
  11                 g.TextBuffer.__init__(self, None)
  12                 self.undo_buffer = []
  13                 self.redo_buffer = []   # Will be None during undo or redo
  14
  15         def start_undo_history(self):
  16                 self.connect('delete-range', self.delete_range)
  17                 self.connect('insert-text', self.insert_text)
  18
  19         def delete_range(self, buffer, start, end):
  20                 self.undo_buffer.append((INSERT,
  21                                          start.get_offset(),
  22                                          buffer.get_slice(start, end, g.TRUE)))
  23                 if self.redo_buffer:
  24                         self.redo_buffer = []
  25
  26         def insert_text(self, buffer, where, text, len):
  27                 start = where.get_offset()
  28                 self.undo_buffer.append((DELETE, start, start + len, text))
  29                 if self.redo_buffer:
  30                         self.redo_buffer = []
  31
  32         def do_action(self, op):
  33                 if op[0] == DELETE:
  34                         start = self.get_iter_at_offset(op[1])
  35                         end = self.get_iter_at_offset(op[2])
  36                         self.delete(start, end)
  37                 elif op[0] == INSERT:
  38                         start = self.get_iter_at_offset(op[1])
  39                         self.insert(start, op[2], -1)
  40                 else:
  41                         rox.alert('Unknown entry in undo buffer!\n' + `op`)
  42
  43         def undo(self):
  44                 if not self.undo_buffer:
  45                         g.gdk.beep()
  46                         return
  47                 op = self.undo_buffer.pop()
  48
  49                 old_undo = self.undo_buffer
  50                 self.undo_buffer = self.redo_buffer # Put undos in redo buffer
  51                 self.redo_buffer = None             # Don't clear redo buffer
  52
  53                 try:
  54                         self.do_action(op)
  55                 finally:
  56                         self.redo_buffer = self.undo_buffer
  57                         self.undo_buffer = old_undo
  58
  59         def redo(self):
  60                 if not self.redo_buffer:
  61                         g.gdk.beep()
  62                         return
  63                 op = self.redo_buffer.pop()
  64
  65                 old_redo = self.redo_buffer
  66                 self.redo_buffer = None         # Don't clear redo buffer
  67
  68                 try:
  69                         self.do_action(op)
  70                 finally:
  71                         self.redo_buffer = old_redo