Preview: undo.py
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/opt/alt/python37/lib64/python3.7/idlelib/undo.py
import string
from idlelib.delegator import Delegator
# tkinter import not needed because module does not create widgets,
# although many methods operate on text widget arguments.
#$ event <<redo>>
#$ win <Control-y>
#$ unix <Alt-z>
#$ event <<undo>>
#$ win <Control-z>
#$ unix <Control-z>
#$ event <<dump-undo-state>>
#$ win <Control-backslash>
#$ unix <Control-backslash>
class UndoDelegator(Delegator):
max_undo = 1000
def __init__(self):
Delegator.__init__(self)
self.reset_undo()
def setdelegate(self, delegate):
if self.delegate is not None:
self.unbind("<<undo>>")
self.unbind("<<redo>>")
self.unbind("<<dump-undo-state>>")
Delegator.setdelegate(self, delegate)
if delegate is not None:
self.bind("<<undo>>", self.undo_event)
self.bind("<<redo>>", self.redo_event)
self.bind("<<dump-undo-state>>", self.dump_event)
def dump_event(self, event):
from pprint import pprint
pprint(self.undolist[:self.pointer])
print("pointer:", self.pointer, end=' ')
print("saved:", self.saved, end=' ')
print("can_merge:", self.can_merge, end=' ')
print("get_saved():", self.get_saved())
pprint(self.undolist[self.pointer:])
return "break"
def reset_undo(self):
self.was_saved = -1
self.pointer = 0
self.undolist = []
self.undoblock = 0 # or a CommandSequence instance
self.set_saved(1)
def set_saved(self, flag):
if flag:
self.saved = self.pointer
else:
self.saved = -1
self.can_merge = False
self.check_saved()
def get_saved(self):
return self.saved == self.pointer
saved_change_hook = None
def set_saved_change_hook(self, hook):
self.saved_change_hook = hook
was_saved = -1
def check_saved(self):
is_saved = self.get_saved()
if is_saved != self.was_saved:
self.was_saved = is_saved
if self.saved_change_hook:
self.saved_change_hook()
def insert(self, index, chars, tags=None):
self.addcmd(InsertCommand(index, chars, tags))
def delete(self, index1, index2=None):
self.addcmd(DeleteCommand(index1, index2))
# Clients should call undo_block_start() and undo_block_stop()
# around a sequence of editing cmds to be treated as a unit by
# undo & redo. Nested matching calls are OK, and the inner calls
# then act like nops. OK too if no editing cmds, or only one
# editing cmd, is issued in between: if no cmds, the whole
# sequence has no effect; and if only one cmd, that cmd is entered
# directly into the undo list, as if undo_block_xxx hadn't been
# called. The intent of all that is to make this scheme easy
# to use: all the client has to worry about is making sure each
# _start() call is matched by a _stop() call.
def undo_block_start(self):
if self.undoblock == 0:
self.undoblock = CommandSequence()
self.undoblock.bump_depth()
def undo_block_stop(self):
if self.undoblock.bump_depth(-1) == 0:
cmd = self.undoblock
self.undoblock = 0
if len(cmd) > 0:
if len(cmd) == 1:
# no need to wrap a single cmd
cmd = cmd.getcmd(0)
# this blk of cmds, or single cmd, has already
# been done, so don't execute it again
self.addcmd(cmd, 0)
def addcmd(self, cmd, execute=True):
if execute:
cmd.do(self.delegate)
if self.undoblock != 0:
self.undoblock.append(cmd)
return
if self.can_merge and self.pointer > 0:
lastcmd = self.undolist[self.pointer-1]
if lastcmd.merge(cmd):
return
self.undolist[self.pointer:] = [cmd]
if self.saved > self.pointer:
self.saved = -1
self.pointer = self.pointer + 1
if len(self.undolist) > self.max_undo:
##print "truncating undo list"
del self.undolist[0]
self.pointer = self.pointer - 1
if self.saved >= 0:
self.saved = self.saved - 1
self.can_merge = True
self.check_saved()
def undo_event(self, event):
if self.pointer == 0:
self.bell()
return "break"
cmd = self.undolist[self.pointer - 1]
cmd.undo(self.delegate)
self.pointer = self.pointer - 1
self.can_merge = False
self.check_saved()
return "break"
def redo_event(self, event):
if self.pointer >= len(self.undolist):
self.bell()
return "break"
cmd = self.undolist[self.pointer]
cmd.redo(self.delegate)
self.pointer = self.pointer + 1
self.can_merge = False
self.check_saved()
return "break"
class Command:
# Base class for Undoable commands
tags = None
def __init__(self, index1, index2, chars, tags=None):
self.marks_before = {}
self.marks_after = {}
self.index1 = index1
self.index2 = index2
self.chars = chars
if tags:
self.tags = tags
def __repr__(self):
s = self.__class__.__name__
t = (self.index1, self.index2, self.chars, self.tags)
if self.tags is None:
t = t[:-1]
return s + repr(t)
def do(self, text):
pass
def redo(self, text):
pass
def undo(self, text):
pass
def merge(self, cmd):
return 0
def save_marks(self, text):
marks = {}
for name in text.mark_names():
if name != "insert" and name != "current":
marks[name] = text.index(name)
return marks
def set_marks(self, text, marks):
for name, index in marks.items():
text.mark_set(name, index)
class InsertCommand(Command):
# Undoable insert command
def __init__(self, index1, chars, tags=None):
Command.__init__(self, index1, None, chars, tags)
def do(self, text):
self.marks_before = self.save_marks(text)
self.index1 = text.index(self.index1)
if text.compare(self.index1, ">", "end-1c"):
# Insert before the final newline
self.index1 = text.index("end-1c")
text.insert(self.index1, self.chars, self.tags)
self.index2 = text.index("%s+%dc" % (self.index1, len(self.chars)))
self.marks_after = self.save_marks(text)
##sys.__stderr__.write("do: %s\n" % self)
def redo(self, text):
text.mark_set('insert', self.index1)
text.insert(self.index1, self.chars, self.tags)
self.set_marks(text, self.marks_after)
text.see('insert')
##sys.__stderr__.write("redo: %s\n" % self)
def undo(self, text):
text.mark_set('insert', self.index1)
text.delete(self.index1, self.index2)
self.set_marks(text, self.marks_before)
text.see('insert')
##sys.__stderr__.write("undo: %s\n" % self)
def merge(self, cmd):
if self.__class__ is not cmd.__class__:
return False
if self.index2 != cmd.index1:
return False
if self.tags != cmd.tags:
return False
if len(cmd.chars) != 1:
return False
if self.chars and \
self.classify(self.chars[-1]) != self.classify(cmd.chars):
return False
self.index2 = cmd.index2
self.chars = self.chars + cmd.chars
return True
alphanumeric = string.ascii_letters + string.digits + "_"
def classify(self, c):
if c in self.alphanumeric:
return "alphanumeric"
if c == "\n":
return "newline"
return "punctuation"
class DeleteCommand(Command):
# Undoable delete command
def __init__(self, index1, index2=None):
Command.__init__(self, index1, index2, None, None)
def do(self, text):
self.marks_before = self.save_marks(text)
self.index1 = text.index(self.index1)
if self.index2:
self.index2 = text.index(self.index2)
else:
self.index2 = text.index(self.index1 + " +1c")
if text.compare(self.index2, ">", "end-1c"):
# Don't delete the final newline
self.index2 = text.index("end-1c")
self.chars = text.get(self.index1, self.index2)
text.delete(self.index1, self.index2)
self.marks_after = self.save_marks(text)
##sys.__stderr__.write("do: %s\n" % self)
def redo(self, text):
text.mark_set('insert', self.index1)
text.delete(self.index1, self.index2)
self.set_marks(text, self.marks_after)
text.see('insert')
##sys.__stderr__.write("redo: %s\n" % self)
def undo(self, text):
text.mark_set('insert', self.index1)
text.insert(self.index1, self.chars)
self.set_marks(text, self.marks_before)
text.see('insert')
##sys.__stderr__.write("undo: %s\n" % self)
class CommandSequence(Command):
# Wrapper for a sequence of undoable cmds to be undone/redone
# as a unit
def __init__(self):
self.cmds = []
self.depth = 0
def __repr__(self):
s = self.__class__.__name__
strs = []
for cmd in self.cmds:
strs.append(" %r" % (cmd,))
return s + "(\n" + ",\n".join(strs) + "\n)"
def __len__(self):
return len(self.cmds)
def append(self, cmd):
self.cmds.append(cmd)
def getcmd(self, i):
return self.cmds[i]
def redo(self, text):
for cmd in self.cmds:
cmd.redo(text)
def undo(self, text):
cmds = self.cmds[:]
cmds.reverse()
for cmd in cmds:
cmd.undo(text)
def bump_depth(self, incr=1):
self.depth = self.depth + incr
return self.depth
def _undo_delegator(parent): # htest #
from tkinter import Toplevel, Text, Button
from idlelib.percolator import Percolator
undowin = Toplevel(parent)
undowin.title("Test UndoDelegator")
x, y = map(int, parent.geometry().split('+')[1:])
undowin.geometry("+%d+%d" % (x, y + 175))
text = Text(undowin, height=10)
text.pack()
text.focus_set()
p = Percolator(text)
d = UndoDelegator()
p.insertfilter(d)
undo = Button(undowin, text="Undo", command=lambda:d.undo_event(None))
undo.pack(side='left')
redo = Button(undowin, text="Redo", command=lambda:d.redo_event(None))
redo.pack(side='left')
dump = Button(undowin, text="Dump", command=lambda:d.dump_event(None))
dump.pack(side='left')
if __name__ == "__main__":
from unittest import main
main('idlelib.idle_test.test_undo', verbosity=2, exit=False)
from idlelib.idle_test.htest import run
run(_undo_delegator)
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