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# Copyright (C) 2005, 2006 by Canonical Ltd
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# Written by Martin Pool.
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# Modified by Johan Rydberg <jrydberg@gnu.org>
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# Modified by Robert Collins <robert.collins@canonical.com>
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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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"""Knit versionedfile implementation.
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A knit is a versioned file implementation that supports efficient append only
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lifeless: the data file is made up of "delta records". each delta record has a delta header
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that contains; (1) a version id, (2) the size of the delta (in lines), and (3) the digest of
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the -expanded data- (ie, the delta applied to the parent). the delta also ends with a
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end-marker; simply "end VERSION"
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delta can be line or full contents.a
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... the 8's there are the index number of the annotation.
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version robertc@robertcollins.net-20051003014215-ee2990904cc4c7ad 7 c7d23b2a5bd6ca00e8e266cec0ec228158ee9f9e
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8 e.set('executable', 'yes')
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8 if elt.get('executable') == 'yes':
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8 ie.executable = True
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end robertc@robertcollins.net-20051003014215-ee2990904cc4c7ad
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09:33 < jrydberg> lifeless: each index is made up of a tuple of; version id, options, position, size, parents
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09:33 < jrydberg> lifeless: the parents are currently dictionary compressed
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09:33 < jrydberg> lifeless: (meaning it currently does not support ghosts)
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09:33 < lifeless> right
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09:33 < jrydberg> lifeless: the position and size is the range in the data file
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so the index sequence is the dictionary compressed sequence number used
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in the deltas to provide line annotation
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# 10:16 < lifeless> make partial index writes safe
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# 10:16 < lifeless> implement 'knit.check()' like weave.check()
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# 10:17 < lifeless> record known ghosts so we can detect when they are filled in rather than the current 'reweave
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# move sha1 out of the content so that join is faster at verifying parents
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# record content length ?
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from cStringIO import StringIO
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from itertools import izip, chain
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import bzrlib.errors as errors
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from bzrlib.errors import FileExists, NoSuchFile, KnitError, \
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InvalidRevisionId, KnitCorrupt, KnitHeaderError, \
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RevisionNotPresent, RevisionAlreadyPresent
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from bzrlib.tuned_gzip import *
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from bzrlib.trace import mutter
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from bzrlib.osutils import contains_whitespace, contains_linebreaks, \
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from bzrlib.versionedfile import VersionedFile, InterVersionedFile
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from bzrlib.tsort import topo_sort
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# TODO: Split out code specific to this format into an associated object.
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# TODO: Can we put in some kind of value to check that the index and data
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# files belong together?
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# TODO: accomodate binaries, perhaps by storing a byte count
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# TODO: function to check whole file
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# TODO: atomically append data, then measure backwards from the cursor
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# position after writing to work out where it was located. we may need to
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# bypass python file buffering.
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INDEX_SUFFIX = '.kndx'
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class KnitContent(object):
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"""Content of a knit version to which deltas can be applied."""
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def __init__(self, lines):
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def annotate_iter(self):
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"""Yield tuples of (origin, text) for each content line."""
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for origin, text in self._lines:
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"""Return a list of (origin, text) tuples."""
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return list(self.annotate_iter())
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def line_delta_iter(self, new_lines):
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"""Generate line-based delta from this content to new_lines."""
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new_texts = [text for origin, text in new_lines._lines]
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old_texts = [text for origin, text in self._lines]
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s = SequenceMatcher(None, old_texts, new_texts)
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for op in s.get_opcodes():
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# ofrom oto length data
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yield (op[1], op[2], op[4]-op[3], new_lines._lines[op[3]:op[4]])
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def line_delta(self, new_lines):
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return list(self.line_delta_iter(new_lines))
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return [text for origin, text in self._lines]
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class _KnitFactory(object):
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"""Base factory for creating content objects."""
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def make(self, lines, version):
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num_lines = len(lines)
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return KnitContent(zip([version] * num_lines, lines))
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class KnitAnnotateFactory(_KnitFactory):
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"""Factory for creating annotated Content objects."""
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def parse_fulltext(self, content, version):
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"""Convert fulltext to internal representation
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fulltext content is of the format
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revid(utf8) plaintext\n
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internal representation is of the format:
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origin, text = line.split(' ', 1)
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lines.append((origin.decode('utf-8'), text))
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return KnitContent(lines)
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def parse_line_delta_iter(self, lines):
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for result_item in self.parse_line_delta[lines]:
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def parse_line_delta(self, lines, version):
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"""Convert a line based delta into internal representation.
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line delta is in the form of:
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intstart intend intcount
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revid(utf8) newline\n
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internal represnetation is
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(start, end, count, [1..count tuples (revid, newline)])
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# walk through the lines parsing.
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start, end, count = [int(n) for n in header.split(',')]
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origin, text = next().split(' ', 1)
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contents.append((origin.decode('utf-8'), text))
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result.append((start, end, count, contents))
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def lower_fulltext(self, content):
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"""convert a fulltext content record into a serializable form.
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see parse_fulltext which this inverts.
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return ['%s %s' % (o.encode('utf-8'), t) for o, t in content._lines]
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def lower_line_delta(self, delta):
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"""convert a delta into a serializable form.
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See parse_line_delta which this inverts.
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for start, end, c, lines in delta:
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out.append('%d,%d,%d\n' % (start, end, c))
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for origin, text in lines:
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out.append('%s %s' % (origin.encode('utf-8'), text))
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class KnitPlainFactory(_KnitFactory):
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"""Factory for creating plain Content objects."""
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def parse_fulltext(self, content, version):
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"""This parses an unannotated fulltext.
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Note that this is not a noop - the internal representation
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has (versionid, line) - its just a constant versionid.
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return self.make(content, version)
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def parse_line_delta_iter(self, lines, version):
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header = lines.pop(0)
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start, end, c = [int(n) for n in header.split(',')]
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yield start, end, c, zip([version] * c, lines[:c])
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def parse_line_delta(self, lines, version):
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return list(self.parse_line_delta_iter(lines, version))
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def lower_fulltext(self, content):
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return content.text()
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def lower_line_delta(self, delta):
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for start, end, c, lines in delta:
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out.append('%d,%d,%d\n' % (start, end, c))
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out.extend([text for origin, text in lines])
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def make_empty_knit(transport, relpath):
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"""Construct a empty knit at the specified location."""
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k = KnitVersionedFile(transport, relpath, 'w', KnitPlainFactory)
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class KnitVersionedFile(VersionedFile):
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"""Weave-like structure with faster random access.
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A knit stores a number of texts and a summary of the relationships
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between them. Texts are identified by a string version-id. Texts
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are normally stored and retrieved as a series of lines, but can
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also be passed as single strings.
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Lines are stored with the trailing newline (if any) included, to
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avoid special cases for files with no final newline. Lines are
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composed of 8-bit characters, not unicode. The combination of
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these approaches should mean any 'binary' file can be safely
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stored and retrieved.
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def __init__(self, relpath, transport, file_mode=None, access_mode=None, factory=None,
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basis_knit=None, delta=True, create=False):
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"""Construct a knit at location specified by relpath.
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:param create: If not True, only open an existing knit.
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if access_mode is None:
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super(KnitVersionedFile, self).__init__(access_mode)
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assert access_mode in ('r', 'w'), "invalid mode specified %r" % access_mode
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assert not basis_knit or isinstance(basis_knit, KnitVersionedFile), \
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self.transport = transport
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self.filename = relpath
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self.basis_knit = basis_knit
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self.factory = factory or KnitAnnotateFactory()
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self.writable = (access_mode == 'w')
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self._index = _KnitIndex(transport, relpath + INDEX_SUFFIX,
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access_mode, create=create, file_mode=file_mode)
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self._data = _KnitData(transport, relpath + DATA_SUFFIX,
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access_mode, create=create and not len(self), file_mode=file_mode)
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def _add_delta(self, version_id, parents, delta_parent, sha1, noeol, delta):
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"""See VersionedFile._add_delta()."""
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self._check_add(version_id, []) # should we check the lines ?
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self._check_versions_present(parents)
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for parent in parents:
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if not self.has_version(parent):
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ghosts.append(parent)
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present_parents.append(parent)
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if delta_parent is None:
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# reconstitute as full text.
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assert len(delta) == 1 or len(delta) == 0
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assert delta[0][0] == 0
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assert delta[0][1] == 0, delta[0][1]
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return super(KnitVersionedFile, self)._add_delta(version_id,
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options.append('no-eol')
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if delta_parent is not None:
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# determine the current delta chain length.
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# To speed the extract of texts the delta chain is limited
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# to a fixed number of deltas. This should minimize both
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# I/O and the time spend applying deltas.
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delta_parents = [delta_parent]
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parent = delta_parents[0]
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method = self._index.get_method(parent)
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if method == 'fulltext':
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delta_parents = self._index.get_parents(parent)
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if method == 'line-delta':
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# did not find a fulltext in the delta limit.
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# just do a normal insertion.
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return super(KnitVersionedFile, self)._add_delta(version_id,
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options.append('line-delta')
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store_lines = self.factory.lower_line_delta(delta)
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where, size = self._data.add_record(version_id, digest, store_lines)
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self._index.add_version(version_id, options, where, size, parents)
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def clear_cache(self):
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"""Clear the data cache only."""
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self._data.clear_cache()
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def copy_to(self, name, transport):
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"""See VersionedFile.copy_to()."""
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# copy the current index to a temp index to avoid racing with local
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transport.put(name + INDEX_SUFFIX + '.tmp', self.transport.get(self._index._filename),)
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transport.put(name + DATA_SUFFIX, self._data._open_file())
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# rename the copied index into place
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transport.rename(name + INDEX_SUFFIX + '.tmp', name + INDEX_SUFFIX)
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def create_empty(self, name, transport, mode=None):
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return KnitVersionedFile(name, transport, factory=self.factory, delta=self.delta, create=True)
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def _fix_parents(self, version, new_parents):
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"""Fix the parents list for version.
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This is done by appending a new version to the index
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with identical data except for the parents list.
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the parents list must be a superset of the current
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current_values = self._index._cache[version]
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assert set(current_values[4]).difference(set(new_parents)) == set()
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self._index.add_version(version,
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def get_delta(self, version_id):
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"""Get a delta for constructing version from some other version."""
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if not self.has_version(version_id):
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raise RevisionNotPresent(version_id, self.filename)
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parents = self.get_parents(version_id)
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data_pos, data_size = self._index.get_position(version_id)
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data, sha1 = self._data.read_records(((version_id, data_pos, data_size),))[version_id]
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version_idx = self._index.lookup(version_id)
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noeol = 'no-eol' in self._index.get_options(version_id)
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if 'fulltext' == self._index.get_method(version_id):
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new_content = self.factory.parse_fulltext(data, version_idx)
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if parent is not None:
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reference_content = self._get_content(parent)
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old_texts = reference_content.text()
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new_texts = new_content.text()
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delta_seq = SequenceMatcher(None, old_texts, new_texts)
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return parent, sha1, noeol, self._make_line_delta(delta_seq, new_content)
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delta = self.factory.parse_line_delta(data, version_idx)
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return parent, sha1, noeol, delta
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def get_graph_with_ghosts(self):
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"""See VersionedFile.get_graph_with_ghosts()."""
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graph_items = self._index.get_graph()
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return dict(graph_items)
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def get_sha1(self, version_id):
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"""See VersionedFile.get_sha1()."""
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components = self._get_components(version_id)
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return components[-1][-1][-1]
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"""See VersionedFile.get_suffixes()."""
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return [DATA_SUFFIX, INDEX_SUFFIX]
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def has_ghost(self, version_id):
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"""True if there is a ghost reference in the file to version_id."""
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if self.has_version(version_id):
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# optimisable if needed by memoising the _ghosts set.
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items = self._index.get_graph()
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for node, parents in items:
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for parent in parents:
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if parent not in self._index._cache:
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if parent == version_id:
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"""See VersionedFile.versions."""
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return self._index.get_versions()
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def has_version(self, version_id):
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"""See VersionedFile.has_version."""
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return self._index.has_version(version_id)
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__contains__ = has_version
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def _merge_annotations(self, content, parents, parent_texts={},
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delta=None, annotated=None):
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"""Merge annotations for content. This is done by comparing
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the annotations based on changed to the text.
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for parent_id in parents:
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merge_content = self._get_content(parent_id, parent_texts)
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seq = SequenceMatcher(None, merge_content.text(), content.text())
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if delta_seq is None:
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# setup a delta seq to reuse.
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for i, j, n in seq.get_matching_blocks():
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# this appears to copy (origin, text) pairs across to the new
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# content for any line that matches the last-checked parent.
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# FIXME: save the sequence control data for delta compression
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# against the most relevant parent rather than rediffing.
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content._lines[j:j+n] = merge_content._lines[i:i+n]
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reference_content = self._get_content(parents[0], parent_texts)
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new_texts = content.text()
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old_texts = reference_content.text()
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delta_seq = SequenceMatcher(None, old_texts, new_texts)
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return self._make_line_delta(delta_seq, content)
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def _make_line_delta(self, delta_seq, new_content):
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"""Generate a line delta from delta_seq and new_content."""
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for op in delta_seq.get_opcodes():
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diff_hunks.append((op[1], op[2], op[4]-op[3], new_content._lines[op[3]:op[4]]))
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def _get_components(self, version_id):
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"""Return a list of (version_id, method, data) tuples that
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makes up version specified by version_id of the knit.
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The components should be applied in the order of the returned
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The basis knit will be used to the largest extent possible
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since it is assumed that accesses to it is faster.
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# 4168 calls in 14912, 2289 internal
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# 4168 in 9711 to read_records
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# 52554 in 1250 to get_parents
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# 170166 in 865 to list.append
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# needed_revisions holds a list of (method, version_id) of
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# versions that is needed to be fetched to construct the final
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# version of the file.
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# basis_revisions is a list of versions that needs to be
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# fetched but exists in the basis knit.
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basis = self.basis_knit
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if basis and basis._index.has_version(cursor):
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basis_versions.append(cursor)
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method = picked_knit._index.get_method(cursor)
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needed_versions.append((method, cursor))
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if method == 'fulltext':
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cursor = picked_knit.get_parents(cursor)[0]
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for comp_id in basis_versions:
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data_pos, data_size = basis._index.get_data_position(comp_id)
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records.append((piece_id, data_pos, data_size))
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components.update(basis._data.read_records(records))
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for comp_id in [vid for method, vid in needed_versions
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if vid not in basis_versions]:
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data_pos, data_size = self._index.get_position(comp_id)
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records.append((comp_id, data_pos, data_size))
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components.update(self._data.read_records(records))
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# get_data_records returns a mapping with the version id as
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# index and the value as data. The order the components need
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# to be applied is held by needed_versions (reversed).
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for method, comp_id in reversed(needed_versions):
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out.append((comp_id, method, components[comp_id]))
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def _get_content(self, version_id, parent_texts={}):
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"""Returns a content object that makes up the specified
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if not self.has_version(version_id):
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raise RevisionNotPresent(version_id, self.filename)
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cached_version = parent_texts.get(version_id, None)
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if cached_version is not None:
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return cached_version
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if self.basis_knit and version_id in self.basis_knit:
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return self.basis_knit._get_content(version_id)
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components = self._get_components(version_id)
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for component_id, method, (data, digest) in components:
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version_idx = self._index.lookup(component_id)
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if method == 'fulltext':
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assert content is None
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content = self.factory.parse_fulltext(data, version_idx)
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elif method == 'line-delta':
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delta = self.factory.parse_line_delta(data, version_idx)
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content._lines = self._apply_delta(content._lines, delta)
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if 'no-eol' in self._index.get_options(version_id):
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line = content._lines[-1][1].rstrip('\n')
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content._lines[-1] = (content._lines[-1][0], line)
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# digest here is the digest from the last applied component.
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if sha_strings(content.text()) != digest:
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import pdb;pdb.set_trace()
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raise KnitCorrupt(self.filename, 'sha-1 does not match %s' % version_id)
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def _check_versions_present(self, version_ids):
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"""Check that all specified versions are present."""
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version_ids = set(version_ids)
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for r in list(version_ids):
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if self._index.has_version(r):
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version_ids.remove(r)
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raise RevisionNotPresent(list(version_ids)[0], self.filename)
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def _add_lines_with_ghosts(self, version_id, parents, lines, parent_texts):
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"""See VersionedFile.add_lines_with_ghosts()."""
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self._check_add(version_id, lines)
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return self._add(version_id, lines[:], parents, self.delta, parent_texts)
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def _add_lines(self, version_id, parents, lines, parent_texts):
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"""See VersionedFile.add_lines."""
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self._check_add(version_id, lines)
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self._check_versions_present(parents)
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return self._add(version_id, lines[:], parents, self.delta, parent_texts)
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def _check_add(self, version_id, lines):
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"""check that version_id and lines are safe to add."""
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assert self.writable, "knit is not opened for write"
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### FIXME escape. RBC 20060228
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if contains_whitespace(version_id):
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raise InvalidRevisionId(version_id)
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if self.has_version(version_id):
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raise RevisionAlreadyPresent(version_id, self.filename)
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self._check_lines_not_unicode(lines)
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self._check_lines_are_lines(lines)
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def _add(self, version_id, lines, parents, delta, parent_texts):
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"""Add a set of lines on top of version specified by parents.
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If delta is true, compress the text as a line-delta against
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Any versions not present will be converted into ghosts.
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# 461 0 6546.0390 43.9100 bzrlib.knit:489(_add)
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# +400 0 889.4890 418.9790 +bzrlib.knit:192(lower_fulltext)
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# +461 0 1364.8070 108.8030 +bzrlib.knit:996(add_record)
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# +461 0 193.3940 41.5720 +bzrlib.knit:898(add_version)
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# +461 0 134.0590 18.3810 +bzrlib.osutils:361(sha_strings)
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# +461 0 36.3420 15.4540 +bzrlib.knit:146(make)
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# +1383 0 8.0370 8.0370 +<len>
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# +61 0 13.5770 7.9190 +bzrlib.knit:199(lower_line_delta)
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# +61 0 963.3470 7.8740 +bzrlib.knit:427(_get_content)
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# +61 0 973.9950 5.2950 +bzrlib.knit:136(line_delta)
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# +61 0 1918.1800 5.2640 +bzrlib.knit:359(_merge_annotations)
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if parent_texts is None:
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for parent in parents:
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if not self.has_version(parent):
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ghosts.append(parent)
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present_parents.append(parent)
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if delta and not len(present_parents):
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digest = sha_strings(lines)
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if lines[-1][-1] != '\n':
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options.append('no-eol')
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lines[-1] = lines[-1] + '\n'
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if len(present_parents) and delta:
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# To speed the extract of texts the delta chain is limited
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# to a fixed number of deltas. This should minimize both
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# I/O and the time spend applying deltas.
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delta_parents = present_parents
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parent = delta_parents[0]
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method = self._index.get_method(parent)
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if method == 'fulltext':
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delta_parents = self._index.get_parents(parent)
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if method == 'line-delta':
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lines = self.factory.make(lines, version_id)
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if delta or (self.factory.annotated and len(present_parents) > 0):
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# Merge annotations from parent texts if so is needed.
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delta_hunks = self._merge_annotations(lines, present_parents, parent_texts,
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delta, self.factory.annotated)
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options.append('line-delta')
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store_lines = self.factory.lower_line_delta(delta_hunks)
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options.append('fulltext')
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store_lines = self.factory.lower_fulltext(lines)
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where, size = self._data.add_record(version_id, digest, store_lines)
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self._index.add_version(version_id, options, where, size, parents)
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def check(self, progress_bar=None):
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"""See VersionedFile.check()."""
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def _clone_text(self, new_version_id, old_version_id, parents):
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"""See VersionedFile.clone_text()."""
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# FIXME RBC 20060228 make fast by only inserting an index with null delta.
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self.add_lines(new_version_id, parents, self.get_lines(old_version_id))
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def get_lines(self, version_id):
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"""See VersionedFile.get_lines()."""
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return self._get_content(version_id).text()
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def iter_lines_added_or_present_in_versions(self, version_ids=None):
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"""See VersionedFile.iter_lines_added_or_present_in_versions()."""
708
if version_ids is None:
709
version_ids = self.versions()
710
# we dont care about inclusions, the caller cares.
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# but we need to setup a list of records to visit.
712
# we need version_id, position, length
713
version_id_records = []
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requested_versions = list(version_ids)
715
# filter for available versions
716
for version_id in requested_versions:
717
if not self.has_version(version_id):
718
raise RevisionNotPresent(version_id, self.filename)
719
# get a in-component-order queue:
721
for version_id in self.versions():
722
if version_id in requested_versions:
723
version_ids.append(version_id)
724
data_pos, length = self._index.get_position(version_id)
725
version_id_records.append((version_id, data_pos, length))
727
pb = bzrlib.ui.ui_factory.nested_progress_bar()
729
total = len(version_id_records)
731
pb.update('Walking content.', count, total)
732
for version_id, data, sha_value in \
733
self._data.read_records_iter(version_id_records):
734
pb.update('Walking content.', count, total)
735
method = self._index.get_method(version_id)
736
version_idx = self._index.lookup(version_id)
737
assert method in ('fulltext', 'line-delta')
738
if method == 'fulltext':
739
content = self.factory.parse_fulltext(data, version_idx)
740
for line in content.text():
743
delta = self.factory.parse_line_delta(data, version_idx)
744
for start, end, count, lines in delta:
745
for origin, line in lines:
748
pb.update('Walking content.', total, total)
751
pb.update('Walking content.', total, total)
755
def num_versions(self):
756
"""See VersionedFile.num_versions()."""
757
return self._index.num_versions()
759
__len__ = num_versions
761
def annotate_iter(self, version_id):
762
"""See VersionedFile.annotate_iter."""
763
content = self._get_content(version_id)
764
for origin, text in content.annotate_iter():
767
def get_parents(self, version_id):
768
"""See VersionedFile.get_parents."""
771
# 52554 calls in 1264 872 internal down from 3674
773
return self._index.get_parents(version_id)
775
raise RevisionNotPresent(version_id, self.filename)
777
def get_parents_with_ghosts(self, version_id):
778
"""See VersionedFile.get_parents."""
780
return self._index.get_parents_with_ghosts(version_id)
782
raise RevisionNotPresent(version_id, self.filename)
784
def get_ancestry(self, versions):
785
"""See VersionedFile.get_ancestry."""
786
if isinstance(versions, basestring):
787
versions = [versions]
790
self._check_versions_present(versions)
791
return self._index.get_ancestry(versions)
793
def get_ancestry_with_ghosts(self, versions):
794
"""See VersionedFile.get_ancestry_with_ghosts."""
795
if isinstance(versions, basestring):
796
versions = [versions]
799
self._check_versions_present(versions)
800
return self._index.get_ancestry_with_ghosts(versions)
802
#@deprecated_method(zero_eight)
803
def walk(self, version_ids):
804
"""See VersionedFile.walk."""
805
# We take the short path here, and extract all relevant texts
806
# and put them in a weave and let that do all the work. Far
807
# from optimal, but is much simpler.
808
# FIXME RB 20060228 this really is inefficient!
809
from bzrlib.weave import Weave
811
w = Weave(self.filename)
812
ancestry = self.get_ancestry(version_ids)
813
sorted_graph = topo_sort(self._index.get_graph())
814
version_list = [vid for vid in sorted_graph if vid in ancestry]
816
for version_id in version_list:
817
lines = self.get_lines(version_id)
818
w.add_lines(version_id, self.get_parents(version_id), lines)
820
for lineno, insert_id, dset, line in w.walk(version_ids):
821
yield lineno, insert_id, dset, line
823
def plan_merge(self, ver_a, ver_b):
824
"""See VersionedFile.plan_merge."""
825
ancestors_b = set(self.get_ancestry(ver_b))
826
def status_a(revision, text):
827
if revision in ancestors_b:
828
return 'killed-b', text
832
ancestors_a = set(self.get_ancestry(ver_a))
833
def status_b(revision, text):
834
if revision in ancestors_a:
835
return 'killed-a', text
839
annotated_a = self.annotate(ver_a)
840
annotated_b = self.annotate(ver_b)
841
plain_a = [t for (a, t) in annotated_a]
842
plain_b = [t for (a, t) in annotated_b]
843
blocks = SequenceMatcher(None, plain_a, plain_b).get_matching_blocks()
846
for ai, bi, l in blocks:
847
# process all mismatched sections
848
# (last mismatched section is handled because blocks always
849
# includes a 0-length last block)
850
for revision, text in annotated_a[a_cur:ai]:
851
yield status_a(revision, text)
852
for revision, text in annotated_b[b_cur:bi]:
853
yield status_b(revision, text)
855
# and now the matched section
858
for text_a, text_b in zip(plain_a[ai:a_cur], plain_b[bi:b_cur]):
859
assert text_a == text_b
860
yield "unchanged", text_a
863
class _KnitComponentFile(object):
864
"""One of the files used to implement a knit database"""
866
def __init__(self, transport, filename, mode, file_mode=None):
867
self._transport = transport
868
self._filename = filename
870
self._file_mode=file_mode
872
def write_header(self):
873
if self._transport.append(self._filename, StringIO(self.HEADER),
874
mode=self._file_mode):
875
raise KnitCorrupt(self._filename, 'misaligned after writing header')
877
def check_header(self, fp):
879
if line != self.HEADER:
880
raise KnitHeaderError(badline=line)
883
"""Commit is a nop."""
886
return '%s(%s)' % (self.__class__.__name__, self._filename)
889
class _KnitIndex(_KnitComponentFile):
890
"""Manages knit index file.
892
The index is already kept in memory and read on startup, to enable
893
fast lookups of revision information. The cursor of the index
894
file is always pointing to the end, making it easy to append
897
_cache is a cache for fast mapping from version id to a Index
900
_history is a cache for fast mapping from indexes to version ids.
902
The index data format is dictionary compressed when it comes to
903
parent references; a index entry may only have parents that with a
904
lover index number. As a result, the index is topological sorted.
906
Duplicate entries may be written to the index for a single version id
907
if this is done then the latter one completely replaces the former:
908
this allows updates to correct version and parent information.
909
Note that the two entries may share the delta, and that successive
910
annotations and references MUST point to the first entry.
912
The index file on disc contains a header, followed by one line per knit
913
record. The same revision can be present in an index file more than once.
914
The first occurence gets assigned a sequence number starting from 0.
916
The format of a single line is
917
REVISION_ID FLAGS BYTE_OFFSET LENGTH( PARENT_ID|PARENT_SEQUENCE_ID)* :\n
918
REVISION_ID is a utf8-encoded revision id
919
FLAGS is a comma separated list of flags about the record. Values include
920
no-eol, line-delta, fulltext.
921
BYTE_OFFSET is the ascii representation of the byte offset in the data file
922
that the the compressed data starts at.
923
LENGTH is the ascii representation of the length of the data file.
924
PARENT_ID a utf-8 revision id prefixed by a '.' that is a parent of
926
PARENT_SEQUENCE_ID the ascii representation of the sequence number of a
927
revision id already in the knit that is a parent of REVISION_ID.
928
The ' :' marker is the end of record marker.
931
when a write is interrupted to the index file, it will result in a line that
932
does not end in ' :'. If the ' :' is not present at the end of a line, or at
933
the end of the file, then the record that is missing it will be ignored by
936
When writing new records to the index file, the data is preceeded by '\n'
937
to ensure that records always start on new lines even if the last write was
938
interrupted. As a result its normal for the last line in the index to be
939
missing a trailing newline. One can be added with no harmful effects.
942
HEADER = "# bzr knit index 8\n"
944
# speed of knit parsing went from 280 ms to 280 ms with slots addition.
945
# __slots__ = ['_cache', '_history', '_transport', '_filename']
947
def _cache_version(self, version_id, options, pos, size, parents):
948
"""Cache a version record in the history array and index cache.
950
This is inlined into __init__ for performance. KEEP IN SYNC.
951
(It saves 60ms, 25% of the __init__ overhead on local 4000 record
954
# only want the _history index to reference the 1st index entry
956
if version_id not in self._cache:
957
index = len(self._history)
958
self._history.append(version_id)
960
index = self._cache[version_id][5]
961
self._cache[version_id] = (version_id,
968
def __init__(self, transport, filename, mode, create=False, file_mode=None):
969
_KnitComponentFile.__init__(self, transport, filename, mode, file_mode)
971
# position in _history is the 'official' index for a revision
972
# but the values may have come from a newer entry.
973
# so - wc -l of a knit index is != the number of uniqe names
976
pb = bzrlib.ui.ui_factory.nested_progress_bar()
981
pb.update('read knit index', count, total)
982
fp = self._transport.get(self._filename)
983
self.check_header(fp)
984
# readlines reads the whole file at once:
985
# bad for transports like http, good for local disk
986
# we save 60 ms doing this one change (
987
# from calling readline each time to calling
989
# probably what we want for nice behaviour on
990
# http is a incremental readlines that yields, or
991
# a check for local vs non local indexes,
992
for l in fp.readlines():
994
if len(rec) < 5 or rec[-1] != ':':
996
# FIXME: in the future we should determine if its a
997
# short write - and ignore it
998
# or a different failure, and raise. RBC 20060407
1002
#pb.update('read knit index', count, total)
1003
# See self._parse_parents
1005
for value in rec[4:-1]:
1007
# uncompressed reference
1008
parents.append(value[1:])
1010
# this is 15/4000ms faster than isinstance,
1012
# this function is called thousands of times a
1013
# second so small variations add up.
1014
assert value.__class__ is str
1015
parents.append(self._history[int(value)])
1016
# end self._parse_parents
1017
# self._cache_version(rec[0],
1018
# rec[1].split(','),
1022
# --- self._cache_version
1023
# only want the _history index to reference the 1st
1024
# index entry for version_id
1026
if version_id not in self._cache:
1027
index = len(self._history)
1028
self._history.append(version_id)
1030
index = self._cache[version_id][5]
1031
self._cache[version_id] = (version_id,
1037
# --- self._cache_version
1038
except NoSuchFile, e:
1039
if mode != 'w' or not create:
1043
pb.update('read knit index', total, total)
1046
def _parse_parents(self, compressed_parents):
1047
"""convert a list of string parent values into version ids.
1049
ints are looked up in the index.
1050
.FOO values are ghosts and converted in to FOO.
1052
NOTE: the function is retained here for clarity, and for possible
1053
use in partial index reads. However bulk processing now has
1054
it inlined in __init__ for inner-loop optimisation.
1057
for value in compressed_parents:
1058
if value[-1] == '.':
1059
# uncompressed reference
1060
result.append(value[1:])
1062
# this is 15/4000ms faster than isinstance,
1063
# this function is called thousands of times a
1064
# second so small variations add up.
1065
assert value.__class__ is str
1066
result.append(self._history[int(value)])
1069
def get_graph(self):
1071
for version_id, index in self._cache.iteritems():
1072
graph.append((version_id, index[4]))
1075
def get_ancestry(self, versions):
1076
"""See VersionedFile.get_ancestry."""
1077
# get a graph of all the mentioned versions:
1079
pending = set(versions)
1081
version = pending.pop()
1082
parents = self._cache[version][4]
1083
# got the parents ok
1085
parents = [parent for parent in parents if parent in self._cache]
1086
for parent in parents:
1087
# if not completed and not a ghost
1088
if parent not in graph:
1090
graph[version] = parents
1091
return topo_sort(graph.items())
1093
def get_ancestry_with_ghosts(self, versions):
1094
"""See VersionedFile.get_ancestry_with_ghosts."""
1095
# get a graph of all the mentioned versions:
1097
pending = set(versions)
1099
version = pending.pop()
1101
parents = self._cache[version][4]
1107
# got the parents ok
1108
for parent in parents:
1109
if parent not in graph:
1111
graph[version] = parents
1112
return topo_sort(graph.items())
1114
def num_versions(self):
1115
return len(self._history)
1117
__len__ = num_versions
1119
def get_versions(self):
1120
return self._history
1122
def idx_to_name(self, idx):
1123
return self._history[idx]
1125
def lookup(self, version_id):
1126
assert version_id in self._cache
1127
return self._cache[version_id][5]
1129
def _version_list_to_index(self, versions):
1131
for version in versions:
1132
if version in self._cache:
1133
# -- inlined lookup() --
1134
result_list.append(str(self._cache[version][5]))
1135
# -- end lookup () --
1137
result_list.append('.' + version.encode('utf-8'))
1138
return ' '.join(result_list)
1140
def add_version(self, version_id, options, pos, size, parents):
1141
"""Add a version record to the index."""
1142
self._cache_version(version_id, options, pos, size, parents)
1144
content = "\n%s %s %s %s %s :" % (version_id.encode('utf-8'),
1148
self._version_list_to_index(parents))
1149
assert isinstance(content, str), 'content must be utf-8 encoded'
1150
self._transport.append(self._filename, StringIO(content))
1152
def has_version(self, version_id):
1153
"""True if the version is in the index."""
1154
return self._cache.has_key(version_id)
1156
def get_position(self, version_id):
1157
"""Return data position and size of specified version."""
1158
return (self._cache[version_id][2], \
1159
self._cache[version_id][3])
1161
def get_method(self, version_id):
1162
"""Return compression method of specified version."""
1163
options = self._cache[version_id][1]
1164
if 'fulltext' in options:
1167
assert 'line-delta' in options
1170
def get_options(self, version_id):
1171
return self._cache[version_id][1]
1173
def get_parents(self, version_id):
1174
"""Return parents of specified version ignoring ghosts."""
1175
return [parent for parent in self._cache[version_id][4]
1176
if parent in self._cache]
1178
def get_parents_with_ghosts(self, version_id):
1179
"""Return parents of specified version wth ghosts."""
1180
return self._cache[version_id][4]
1182
def check_versions_present(self, version_ids):
1183
"""Check that all specified versions are present."""
1184
version_ids = set(version_ids)
1185
for version_id in list(version_ids):
1186
if version_id in self._cache:
1187
version_ids.remove(version_id)
1189
raise RevisionNotPresent(list(version_ids)[0], self.filename)
1192
class _KnitData(_KnitComponentFile):
1193
"""Contents of the knit data file"""
1195
HEADER = "# bzr knit data 8\n"
1197
def __init__(self, transport, filename, mode, create=False, file_mode=None):
1198
_KnitComponentFile.__init__(self, transport, filename, mode)
1200
self._checked = False
1202
self._transport.put(self._filename, StringIO(''), mode=file_mode)
1205
def clear_cache(self):
1206
"""Clear the record cache."""
1209
def _open_file(self):
1210
if self._file is None:
1212
self._file = self._transport.get(self._filename)
1217
def _record_to_data(self, version_id, digest, lines):
1218
"""Convert version_id, digest, lines into a raw data block.
1220
:return: (len, a StringIO instance with the raw data ready to read.)
1223
data_file = GzipFile(None, mode='wb', fileobj=sio)
1224
data_file.writelines(chain(
1225
["version %s %d %s\n" % (version_id.encode('utf-8'),
1229
["end %s\n" % version_id.encode('utf-8')]))
1236
def add_raw_record(self, raw_data):
1237
"""Append a prepared record to the data file."""
1238
assert isinstance(raw_data, str), 'data must be plain bytes'
1239
start_pos = self._transport.append(self._filename, StringIO(raw_data))
1240
return start_pos, len(raw_data)
1242
def add_record(self, version_id, digest, lines):
1243
"""Write new text record to disk. Returns the position in the
1244
file where it was written."""
1245
size, sio = self._record_to_data(version_id, digest, lines)
1247
self._records[version_id] = (digest, lines)
1249
start_pos = self._transport.append(self._filename, sio)
1250
return start_pos, size
1252
def _parse_record_header(self, version_id, raw_data):
1253
"""Parse a record header for consistency.
1255
:return: the header and the decompressor stream.
1256
as (stream, header_record)
1258
df = GzipFile(mode='rb', fileobj=StringIO(raw_data))
1259
rec = df.readline().split()
1261
raise KnitCorrupt(self._filename, 'unexpected number of elements in record header')
1262
if rec[1].decode('utf-8')!= version_id:
1263
raise KnitCorrupt(self._filename,
1264
'unexpected version, wanted %r, got %r' % (
1265
version_id, rec[1]))
1268
def _parse_record(self, version_id, data):
1270
# 4168 calls in 2880 217 internal
1271
# 4168 calls to _parse_record_header in 2121
1272
# 4168 calls to readlines in 330
1273
df, rec = self._parse_record_header(version_id, data)
1274
record_contents = df.readlines()
1275
l = record_contents.pop()
1276
assert len(record_contents) == int(rec[2])
1277
if l.decode('utf-8') != 'end %s\n' % version_id:
1278
raise KnitCorrupt(self._filename, 'unexpected version end line %r, wanted %r'
1281
return record_contents, rec[3]
1283
def read_records_iter_raw(self, records):
1284
"""Read text records from data file and yield raw data.
1286
This unpacks enough of the text record to validate the id is
1287
as expected but thats all.
1289
It will actively recompress currently cached records on the
1290
basis that that is cheaper than I/O activity.
1293
for version_id, pos, size in records:
1294
if version_id not in self._records:
1295
needed_records.append((version_id, pos, size))
1297
# setup an iterator of the external records:
1298
# uses readv so nice and fast we hope.
1299
if len(needed_records):
1300
# grab the disk data needed.
1301
raw_records = self._transport.readv(self._filename,
1302
[(pos, size) for version_id, pos, size in needed_records])
1304
for version_id, pos, size in records:
1305
if version_id in self._records:
1306
# compress a new version
1307
size, sio = self._record_to_data(version_id,
1308
self._records[version_id][0],
1309
self._records[version_id][1])
1310
yield version_id, sio.getvalue()
1312
pos, data = raw_records.next()
1313
# validate the header
1314
df, rec = self._parse_record_header(version_id, data)
1316
yield version_id, data
1319
def read_records_iter(self, records):
1320
"""Read text records from data file and yield result.
1322
Each passed record is a tuple of (version_id, pos, len) and
1323
will be read in the given order. Yields (version_id,
1327
# 60890 calls for 4168 extractions in 5045, 683 internal.
1328
# 4168 calls to readv in 1411
1329
# 4168 calls to parse_record in 2880
1332
for version_id, pos, size in records:
1333
if version_id not in self._records:
1334
needed_records.append((version_id, pos, size))
1336
if len(needed_records):
1337
# We take it that the transport optimizes the fetching as good
1338
# as possible (ie, reads continous ranges.)
1339
response = self._transport.readv(self._filename,
1340
[(pos, size) for version_id, pos, size in needed_records])
1342
for (record_id, pos, size), (pos, data) in izip(iter(needed_records), response):
1343
content, digest = self._parse_record(record_id, data)
1344
self._records[record_id] = (digest, content)
1346
for version_id, pos, size in records:
1347
yield version_id, list(self._records[version_id][1]), self._records[version_id][0]
1349
def read_records(self, records):
1350
"""Read records into a dictionary."""
1352
for record_id, content, digest in self.read_records_iter(records):
1353
components[record_id] = (content, digest)
1357
class InterKnit(InterVersionedFile):
1358
"""Optimised code paths for knit to knit operations."""
1360
_matching_file_factory = KnitVersionedFile
1363
def is_compatible(source, target):
1364
"""Be compatible with knits. """
1366
return (isinstance(source, KnitVersionedFile) and
1367
isinstance(target, KnitVersionedFile))
1368
except AttributeError:
1371
def join(self, pb=None, msg=None, version_ids=None, ignore_missing=False):
1372
"""See InterVersionedFile.join."""
1373
assert isinstance(self.source, KnitVersionedFile)
1374
assert isinstance(self.target, KnitVersionedFile)
1376
if version_ids is None:
1377
version_ids = self.source.versions()
1379
if not ignore_missing:
1380
self.source._check_versions_present(version_ids)
1382
version_ids = set(self.source.versions()).intersection(
1388
pb = bzrlib.ui.ui_factory.nested_progress_bar()
1390
version_ids = list(version_ids)
1391
if None in version_ids:
1392
version_ids.remove(None)
1394
self.source_ancestry = set(self.source.get_ancestry(version_ids))
1395
this_versions = set(self.target._index.get_versions())
1396
needed_versions = self.source_ancestry - this_versions
1397
cross_check_versions = self.source_ancestry.intersection(this_versions)
1398
mismatched_versions = set()
1399
for version in cross_check_versions:
1400
# scan to include needed parents.
1401
n1 = set(self.target.get_parents_with_ghosts(version))
1402
n2 = set(self.source.get_parents_with_ghosts(version))
1404
# FIXME TEST this check for cycles being introduced works
1405
# the logic is we have a cycle if in our graph we are an
1406
# ancestor of any of the n2 revisions.
1412
parent_ancestors = self.source.get_ancestry(parent)
1413
if version in parent_ancestors:
1414
raise errors.GraphCycleError([parent, version])
1415
# ensure this parent will be available later.
1416
new_parents = n2.difference(n1)
1417
needed_versions.update(new_parents.difference(this_versions))
1418
mismatched_versions.add(version)
1420
if not needed_versions and not cross_check_versions:
1422
full_list = topo_sort(self.source.get_graph())
1424
version_list = [i for i in full_list if (not self.target.has_version(i)
1425
and i in needed_versions)]
1429
copy_queue_records = []
1431
for version_id in version_list:
1432
options = self.source._index.get_options(version_id)
1433
parents = self.source._index.get_parents_with_ghosts(version_id)
1434
# check that its will be a consistent copy:
1435
for parent in parents:
1436
# if source has the parent, we must :
1437
# * already have it or
1438
# * have it scheduled already
1439
# otherwise we dont care
1440
assert (self.target.has_version(parent) or
1441
parent in copy_set or
1442
not self.source.has_version(parent))
1443
data_pos, data_size = self.source._index.get_position(version_id)
1444
copy_queue_records.append((version_id, data_pos, data_size))
1445
copy_queue.append((version_id, options, parents))
1446
copy_set.add(version_id)
1448
# data suck the join:
1450
total = len(version_list)
1451
# we want the raw gzip for bulk copying, but the record validated
1452
# just enough to be sure its the right one.
1453
# TODO: consider writev or write combining to reduce
1454
# death of a thousand cuts feeling.
1455
for (version_id, raw_data), \
1456
(version_id2, options, parents) in \
1457
izip(self.source._data.read_records_iter_raw(copy_queue_records),
1459
assert version_id == version_id2, 'logic error, inconsistent results'
1461
pb.update("Joining knit", count, total)
1462
pos, size = self.target._data.add_raw_record(raw_data)
1463
self.target._index.add_version(version_id, options, pos, size, parents)
1465
for version in mismatched_versions:
1466
# FIXME RBC 20060309 is this needed?
1467
n1 = set(self.target.get_parents_with_ghosts(version))
1468
n2 = set(self.source.get_parents_with_ghosts(version))
1469
# write a combined record to our history preserving the current
1470
# parents as first in the list
1471
new_parents = self.target.get_parents_with_ghosts(version) + list(n2.difference(n1))
1472
self.target.fix_parents(version, new_parents)
1478
InterVersionedFile.register_optimiser(InterKnit)
1481
class SequenceMatcher(difflib.SequenceMatcher):
1482
"""Knit tuned sequence matcher.
1484
This is based on profiling of difflib which indicated some improvements
1485
for our usage pattern.
1488
def find_longest_match(self, alo, ahi, blo, bhi):
1489
"""Find longest matching block in a[alo:ahi] and b[blo:bhi].
1491
If isjunk is not defined:
1493
Return (i,j,k) such that a[i:i+k] is equal to b[j:j+k], where
1494
alo <= i <= i+k <= ahi
1495
blo <= j <= j+k <= bhi
1496
and for all (i',j',k') meeting those conditions,
1499
and if i == i', j <= j'
1501
In other words, of all maximal matching blocks, return one that
1502
starts earliest in a, and of all those maximal matching blocks that
1503
start earliest in a, return the one that starts earliest in b.
1505
>>> s = SequenceMatcher(None, " abcd", "abcd abcd")
1506
>>> s.find_longest_match(0, 5, 0, 9)
1509
If isjunk is defined, first the longest matching block is
1510
determined as above, but with the additional restriction that no
1511
junk element appears in the block. Then that block is extended as
1512
far as possible by matching (only) junk elements on both sides. So
1513
the resulting block never matches on junk except as identical junk
1514
happens to be adjacent to an "interesting" match.
1516
Here's the same example as before, but considering blanks to be
1517
junk. That prevents " abcd" from matching the " abcd" at the tail
1518
end of the second sequence directly. Instead only the "abcd" can
1519
match, and matches the leftmost "abcd" in the second sequence:
1521
>>> s = SequenceMatcher(lambda x: x==" ", " abcd", "abcd abcd")
1522
>>> s.find_longest_match(0, 5, 0, 9)
1525
If no blocks match, return (alo, blo, 0).
1527
>>> s = SequenceMatcher(None, "ab", "c")
1528
>>> s.find_longest_match(0, 2, 0, 1)
1532
# CAUTION: stripping common prefix or suffix would be incorrect.
1536
# Longest matching block is "ab", but if common prefix is
1537
# stripped, it's "a" (tied with "b"). UNIX(tm) diff does so
1538
# strip, so ends up claiming that ab is changed to acab by
1539
# inserting "ca" in the middle. That's minimal but unintuitive:
1540
# "it's obvious" that someone inserted "ac" at the front.
1541
# Windiff ends up at the same place as diff, but by pairing up
1542
# the unique 'b's and then matching the first two 'a's.
1544
a, b, b2j, isbjunk = self.a, self.b, self.b2j, self.isbjunk
1545
besti, bestj, bestsize = alo, blo, 0
1546
# find longest junk-free match
1547
# during an iteration of the loop, j2len[j] = length of longest
1548
# junk-free match ending with a[i-1] and b[j]
1552
for i in xrange(alo, ahi):
1553
# look at all instances of a[i] in b; note that because
1554
# b2j has no junk keys, the loop is skipped if a[i] is junk
1555
j2lenget = j2len.get
1558
# changing b2j.get(a[i], nothing) to a try:Keyerror pair produced the
1559
# following improvement
1560
# 704 0 4650.5320 2620.7410 bzrlib.knit:1336(find_longest_match)
1561
# +326674 0 1655.1210 1655.1210 +<method 'get' of 'dict' objects>
1562
# +76519 0 374.6700 374.6700 +<method 'has_key' of 'dict' objects>
1564
# 704 0 3733.2820 2209.6520 bzrlib.knit:1336(find_longest_match)
1565
# +211400 0 1147.3520 1147.3520 +<method 'get' of 'dict' objects>
1566
# +76519 0 376.2780 376.2780 +<method 'has_key' of 'dict' objects>
1578
k = newj2len[j] = 1 + j2lenget(-1 + j, 0)
1580
besti, bestj, bestsize = 1 + i-k, 1 + j-k, k
1583
# Extend the best by non-junk elements on each end. In particular,
1584
# "popular" non-junk elements aren't in b2j, which greatly speeds
1585
# the inner loop above, but also means "the best" match so far
1586
# doesn't contain any junk *or* popular non-junk elements.
1587
while besti > alo and bestj > blo and \
1588
not isbjunk(b[bestj-1]) and \
1589
a[besti-1] == b[bestj-1]:
1590
besti, bestj, bestsize = besti-1, bestj-1, bestsize+1
1591
while besti+bestsize < ahi and bestj+bestsize < bhi and \
1592
not isbjunk(b[bestj+bestsize]) and \
1593
a[besti+bestsize] == b[bestj+bestsize]:
1596
# Now that we have a wholly interesting match (albeit possibly
1597
# empty!), we may as well suck up the matching junk on each
1598
# side of it too. Can't think of a good reason not to, and it
1599
# saves post-processing the (possibly considerable) expense of
1600
# figuring out what to do with it. In the case of an empty
1601
# interesting match, this is clearly the right thing to do,
1602
# because no other kind of match is possible in the regions.
1603
while besti > alo and bestj > blo and \
1604
isbjunk(b[bestj-1]) and \
1605
a[besti-1] == b[bestj-1]:
1606
besti, bestj, bestsize = besti-1, bestj-1, bestsize+1
1607
while besti+bestsize < ahi and bestj+bestsize < bhi and \
1608
isbjunk(b[bestj+bestsize]) and \
1609
a[besti+bestsize] == b[bestj+bestsize]:
1610
bestsize = bestsize + 1
1612
return besti, bestj, bestsize