Pmw/Pmw_1_2/lib/PmwHistoryText.py

   1 import Pmw
   2
   3 _ORIGINAL = 0
   4 _MODIFIED = 1
   5 _DISPLAY = 2
   6
   7 class HistoryText(Pmw.ScrolledText):
   8
   9     def __init__(self, parent = None, **kw):
  10
  11         # Define the megawidget options.
  12         optiondefs = (
  13             ('compressany',         1,          None),
  14             ('compresstail',        1,          None),
  15             ('historycommand',      None,       None),
  16         )
  17         self.defineoptions(kw, optiondefs)
  18
  19         # Initialise the base class (after defining the options).
  20         Pmw.ScrolledText.__init__(self, parent)
  21
  22         # Initialise instance variables.
  23         self._list = []
  24         self._currIndex = 0
  25         self._pastIndex = None
  26         self._lastIndex = 0          # pointer to end of history list
  27
  28         # Check keywords and initialise options.
  29         self.initialiseoptions()
  30
  31     def addhistory(self):
  32         text = self.get()
  33         if text[-1] == '\n':
  34             text = text[:-1]
  35
  36         if len(self._list) == 0:
  37             # This is the first history entry.  Add it.
  38             self._list.append([text, text, _MODIFIED])
  39             return
  40
  41         currentEntry =  self._list[self._currIndex]
  42         if text == currentEntry[_ORIGINAL]:
  43             # The current history entry has not been modified. Check if
  44             # we need to add it again.
  45
  46             if self['compresstail'] and self._currIndex == self._lastIndex:
  47                 return
  48
  49             if self['compressany']:
  50                 return
  51
  52         # Undo any changes for the current history entry, since they
  53         # will now be available in the new entry.
  54         currentEntry[_MODIFIED] = currentEntry[_ORIGINAL]
  55
  56         historycommand = self['historycommand']
  57         if self._currIndex == self._lastIndex:
  58             # The last history entry is currently being displayed,
  59             # so disable the special meaning of the 'Next' button.
  60             self._pastIndex = None
  61             nextState = 'disabled'
  62         else:
  63             # A previous history entry is currently being displayed,
  64             # so allow the 'Next' button to go to the entry after this one.
  65             self._pastIndex = self._currIndex
  66             nextState = 'normal'
  67         if callable(historycommand):
  68             historycommand('normal', nextState)
  69
  70         # Create the new history entry.
  71         self._list.append([text, text, _MODIFIED])
  72
  73         # Move the pointer into the history entry list to the end.
  74         self._lastIndex = self._lastIndex + 1
  75         self._currIndex = self._lastIndex
  76
  77     def next(self):
  78         if self._currIndex == self._lastIndex and self._pastIndex is None:
  79             self.bell()
  80         else:
  81             self._modifyDisplay('next')
  82
  83     def prev(self):
  84         self._pastIndex = None
  85         if self._currIndex == 0:
  86             self.bell()
  87         else:
  88             self._modifyDisplay('prev')
  89
  90     def undo(self):
  91         if len(self._list) != 0:
  92             self._modifyDisplay('undo')
  93
  94     def redo(self):
  95         if len(self._list) != 0:
  96             self._modifyDisplay('redo')
  97
  98     def gethistory(self):
  99         return self._list
 100
 101     def _modifyDisplay(self, command):
 102         # Modify the display to show either the next or previous
 103         # history entry (next, prev) or the original or modified
 104         # version of the current history entry (undo, redo).
 105
 106         # Save the currently displayed text.
 107         currentText = self.get()
 108         if currentText[-1] == '\n':
 109             currentText = currentText[:-1]
 110
 111         currentEntry =  self._list[self._currIndex]
 112         if currentEntry[_DISPLAY] == _MODIFIED:
 113             currentEntry[_MODIFIED] = currentText
 114         elif currentEntry[_ORIGINAL] != currentText:
 115             currentEntry[_MODIFIED] = currentText
 116             if command in ('next', 'prev'):
 117                 currentEntry[_DISPLAY] = _MODIFIED
 118
 119         if command in ('next', 'prev'):
 120             prevstate = 'normal'
 121             nextstate = 'normal'
 122             if command == 'next':
 123                 if self._pastIndex is not None:
 124                     self._currIndex = self._pastIndex
 125                     self._pastIndex = None
 126                 self._currIndex = self._currIndex + 1
 127                 if self._currIndex == self._lastIndex:
 128                     nextstate = 'disabled'
 129             elif command == 'prev':
 130                 self._currIndex = self._currIndex - 1
 131                 if self._currIndex == 0:
 132                     prevstate = 'disabled'
 133             historycommand = self['historycommand']
 134             if callable(historycommand):
 135                 historycommand(prevstate, nextstate)
 136             currentEntry =  self._list[self._currIndex]
 137         else:
 138             if command == 'undo':
 139                 currentEntry[_DISPLAY] = _ORIGINAL
 140             elif command == 'redo':
 141                 currentEntry[_DISPLAY] = _MODIFIED
 142
 143         # Display the new text.
 144         self.delete('1.0', 'end')
 145         self.insert('end', currentEntry[currentEntry[_DISPLAY]])