diff --git a/mercurial/util.py b/mercurial/util.py --- a/mercurial/util.py +++ b/mercurial/util.py @@ -26,6 +26,7 @@ import gc import hashlib import imp +import itertools import mmap import os import platform as pyplatform @@ -3831,3 +3832,26 @@ # convenient shortcut dst = debugstacktrace + +def safename(f, tag, ctx, others=None): + """ + Generate a name that it is safe to rename f to in the given context. + + f: filename to rename + tag: a string tag that will be included in the new name + ctx: a context, in which the new name must not exist + others: a set of other filenames that the new name must not be in + + Returns a file name of the form oldname~tag[~number] which does not exist + in the provided context and is not in the set of other names. + """ + if others is None: + others = set() + + fn = '%s~%s' % (f, tag) + if fn not in ctx and fn not in others: + return fn + for n in itertools.count(1): + fn = '%s~%s~%s' % (f, tag, n) + if fn not in ctx and fn not in others: + return fn