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# Copyright 2007 Owen Taylor
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# This file is part of Reinteract and distributed under the terms
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# of the BSD license. See the file COPYING in the Reinteract
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# distribution for full details.
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########################################################################
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# Two consecutive inserts are merged together if the sum of the
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# two matches this. The (?!\n) is to defeat the normal regular
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# expression behavior where 'a$' matches 'a\n' because $ matches
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# before the last newline in the string
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COALESCE_RE = re.compile(r'^\S+ *(?!\n)$')
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class _InsertDeleteOp(object):
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def __init__(self, start, end, text):
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def _insert(self, worksheet):
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worksheet.begin_user_action()
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worksheet.insert(self.start[0], self.start[1], self.text)
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worksheet.end_user_action()
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worksheet.place_cursor(self.end[0], self.end[1])
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def _delete(self, worksheet):
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worksheet.begin_user_action()
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worksheet.delete_range(self.start[0], self.start[1], self.end[0], self.end[1])
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worksheet.end_user_action()
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worksheet.place_cursor(self.start[0], self.start[1])
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class InsertOp(_InsertDeleteOp):
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def redo(self, worksheet):
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self._insert(worksheet)
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def undo(self, worksheet):
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self._delete(worksheet)
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return "InsertOp(%s, %s, %s)" % (self.start, self.end, repr(self.text))
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class DeleteOp(_InsertDeleteOp):
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def redo(self, worksheet):
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self._delete(worksheet)
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def undo(self, worksheet):
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self._insert(worksheet)
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return "DeleteOp(%s, %s, %s)" % (self.start, self.end, repr(self.text))
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class BeginActionOp(object):
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return "BeginActionOp()"
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class EndActionOp(object):
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return "EndActionOp()"
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class UndoStack(object):
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def __init__(self, worksheet):
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self.__worksheet = worksheet
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# The position at which we last pruned the stack; everything after
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# this has been inserted consecutively without any intervening
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self.__prune_position = 0
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self.__applying_undo = False
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self.__user_action_count = 0
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if self.__position == 0:
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self.__applying_undo = True
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if isinstance(self.__stack[self.__position], EndActionOp):
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while not isinstance(self.__stack[self.__position], BeginActionOp):
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self.__stack[self.__position].undo(self.__worksheet)
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self.__stack[self.__position].undo(self.__worksheet)
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self.__applying_undo = False
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if self.__position == len(self.__stack):
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self.__applying_undo = True
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if isinstance(self.__stack[self.__position - 1], BeginActionOp):
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while not isinstance(self.__stack[self.__position - 1], EndActionOp):
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self.__stack[self.__position - 1].redo(self.__worksheet)
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self.__stack[self.__position - 1].redo(self.__worksheet)
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self.__applying_undo = False
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def __check_coalesce(self):
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assert self.__position == len(self.__stack)
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# Don't coalesce two ops unless they are actually adjacent in time
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if self.__position < self.__prune_position + 2:
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cur = self.__stack[-1]
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prev = self.__stack[-2]
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if isinstance(cur, InsertOp) and isinstance(prev, InsertOp) and \
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cur.start == prev.end and COALESCE_RE.match(prev.text + cur.text):
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prev.text += cur.text
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def append_op(self, op):
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if self.__applying_undo:
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if self.__position < len(self.__stack):
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assert self.__action_ops == 0
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self.__stack[self.__position:] = []
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self.__prune_position = self.__position
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self.__stack.append(op)
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if self.__user_action_count > 0:
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self.__action_ops += 1
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self.__check_coalesce()
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def begin_user_action(self):
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self.__user_action_count += 1
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def end_user_action(self):
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self.__user_action_count -= 1
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if self.__user_action_count == 0:
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if self.__action_ops > 1:
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self.__stack.insert(len(self.__stack) - self.__action_ops, BeginActionOp())
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self.__stack.append(EndActionOp())
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elif self.__action_ops == 1:
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self.__check_coalesce()
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self.__action_ops = 0
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return "UndoStack(stack=%s, position=%d)" % (self.__stack, self.__position)
added
removed
lib/reinteract/undo_stack.py
