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# Copyright (C) 2006 Canonical Ltd
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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"""Common code for generating file or revision ids."""
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from bzrlib.lazy_import import lazy_import
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lazy_import(globals(), """
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# the regex removes any weird characters; we don't escape them
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# but rather just pull them out
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_file_id_chars_re = lazy_regex.lazy_compile(r'[^\w.]')
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_rev_id_chars_re = lazy_regex.lazy_compile(r'[^-\w.+@]')
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_gen_file_id_suffix = None
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_gen_file_id_serial = 0
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def _next_id_suffix():
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"""Create a new file id suffix that is reasonably unique.
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On the first call we combine the current time with 64 bits of randomness to
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give a highly probably globally unique number. Then each call in the same
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process adds 1 to a serial number we append to that unique value.
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# XXX TODO: change bzrlib.add.smart_add to call workingtree.add() rather
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# than having to move the id randomness out of the inner loop like this.
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# XXX TODO: for the global randomness this uses we should add the thread-id
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# before the serial #.
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# XXX TODO: jam 20061102 I think it would be good to reset every 100 or
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# 1000 calls, or perhaps if time.time() increases by a certain
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# amount. time.time() shouldn't be terribly expensive to call,
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# and it means that long-lived processes wouldn't use the same
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global _gen_file_id_suffix, _gen_file_id_serial
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if _gen_file_id_suffix is None:
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_gen_file_id_suffix = "-%s-%s-" % (osutils.compact_date(time.time()),
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osutils.rand_chars(16))
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_gen_file_id_serial += 1
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return _gen_file_id_suffix + str(_gen_file_id_serial)
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def gen_file_id(name):
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"""Return new file id for the basename 'name'.
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The uniqueness is supplied from _next_id_suffix.
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# The real randomness is in the _next_id_suffix, the
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# rest of the identifier is just to be nice.
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# 1) Remove non-ascii word characters to keep the ids portable
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# 2) squash to lowercase, so the file id doesn't have to
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# be escaped (case insensitive filesystems would bork for ids
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# that only differ in case without escaping).
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# 3) truncate the filename to 20 chars. Long filenames also bork on some
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# 4) Removing starting '.' characters to prevent the file ids from
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# being considered hidden.
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ascii_word_only = _file_id_chars_re.sub('', name.lower())
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short_no_dots = ascii_word_only.lstrip('.')[:20]
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return short_no_dots + _next_id_suffix()
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"""Return a new tree-root file id."""
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return gen_file_id('tree_root')
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def gen_revision_id(username, timestamp=None):
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"""Return new revision-id.
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:param username: This is the value returned by config.username(), which is
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typically a real name, followed by an email address. If found, we will
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use just the email address portion. Otherwise we flatten the real name,
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:return: A new revision id.
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user_or_email = config.extract_email_address(username)
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except errors.NoEmailInUsername:
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user_or_email = username
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user_or_email = user_or_email.lower()
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user_or_email = user_or_email.replace(' ', '_')
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user_or_email = _rev_id_chars_re.sub('', user_or_email)
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# This gives 36^16 ~= 2^82.7 ~= 83 bits of entropy
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unique_chunk = osutils.rand_chars(16)
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if timestamp is None:
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timestamp = time.time()
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return '-'.join((user_or_email,
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osutils.compact_date(timestamp),
added
removed
bzrlib/generate_ids.py
