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# Copyright (C) 2007 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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from bzrlib.lazy_import import lazy_import
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lazy_import(globals(), """
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from StringIO import StringIO
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from bzrlib.util import bencode
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from bzrlib.tuned_gzip import GzipFile
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def topo_iter(vf, versions=None):
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versions = vf.versions()
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def pending_parents(version):
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return [v for v in vf.get_parents(version) if v in versions and
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for version_id in versions:
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for parent_id in vf.get_parents(version_id):
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descendants.setdefault(parent_id, []).append(version_id)
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cur = [v for v in versions if len(pending_parents(v)) == 0]
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for version_id in cur:
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if version_id in seen:
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if len(pending_parents(version_id)) != 0:
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next.extend(descendants.get(version_id, []))
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assert len(seen) == len(versions)
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class MultiParent(object):
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"""A multi-parent diff"""
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def __init__(self, hunks=None):
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return "MultiParent(%r)" % self.hunks
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def __eq__(self, other):
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if self.__class__ is not other.__class__:
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return (self.hunks == other.hunks)
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def from_lines(text, parents=(), left_blocks=None):
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"""Produce a MultiParent from a list of lines and parents"""
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matcher = patiencediff.PatienceSequenceMatcher(None, parent,
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return matcher.get_matching_blocks()
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if left_blocks is None:
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left_blocks = compare(parents[0])
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parent_comparisons = [left_blocks] + [compare(p) for p in
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parent_comparisons = []
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new_text = NewText([])
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block_iter = [iter(i) for i in parent_comparisons]
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diff = MultiParent([])
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return block_iter[p].next()
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except StopIteration:
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cur_block = [next_block(p) for p, i in enumerate(block_iter)]
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while cur_line < len(text):
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for p, block in enumerate(cur_block):
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while j + n <= cur_line:
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block = cur_block[p] = next_block(p)
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offset = cur_line - j
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if best_match is None or n > best_match.num_lines:
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best_match = ParentText(p, i, j, n)
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if best_match is None:
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new_text.lines.append(text[cur_line])
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if len(new_text.lines) > 0:
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diff.hunks.append(new_text)
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new_text = NewText([])
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diff.hunks.append(best_match)
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cur_line += best_match.num_lines
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if len(new_text.lines) > 0:
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diff.hunks.append(new_text)
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def get_matching_blocks(self, parent, parent_len):
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for hunk in self.hunks:
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if not isinstance(hunk, ParentText) or hunk.parent != parent:
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yield (hunk.parent_pos, hunk.child_pos, hunk.num_lines)
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yield parent_len, self.num_lines(), 0
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def to_lines(self, parents=()):
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"""Contruct a fulltext from this diff and its parents"""
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mpvf = MultiMemoryVersionedFile()
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for num, parent in enumerate(parents):
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mpvf.add_version(StringIO(parent).readlines(), num, [])
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mpvf.add_diff(self, 'a', range(len(parents)))
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return mpvf.get_line_list(['a'])[0]
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def from_texts(cls, text, parents=()):
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"""Produce a MultiParent from a text and list of parent text"""
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return cls.from_lines(StringIO(text).readlines(),
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[StringIO(p).readlines() for p in parents])
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"""Yield text lines for a patch"""
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for hunk in self.hunks:
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for line in hunk.to_patch():
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return len(''.join(self.to_patch()))
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def zipped_patch_len(self):
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return len(gzip_string(self.to_patch()))
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def from_patch(cls, text):
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"""Create a MultiParent from its string form"""
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return cls._from_patch(StringIO(text))
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def _from_patch(lines):
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"""This is private because it is essential to split lines on \n only"""
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line_iter = iter(lines)
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cur_line = line_iter.next()
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except StopIteration:
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if cur_line[0] == 'i':
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num_lines = int(cur_line.split(' ')[1])
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hunk_lines = [line_iter.next() for x in xrange(num_lines)]
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hunk_lines[-1] = hunk_lines[-1][:-1]
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hunks.append(NewText(hunk_lines))
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elif cur_line[0] == '\n':
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hunks[-1].lines[-1] += '\n'
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assert cur_line[0] == 'c', cur_line[0]
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parent, parent_pos, child_pos, num_lines =\
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[int(v) for v in cur_line.split(' ')[1:]]
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hunks.append(ParentText(parent, parent_pos, child_pos,
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return MultiParent(hunks)
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def range_iterator(self):
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"""Iterate through the hunks, with range indicated
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kind is "new" or "parent".
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for "new", data is a list of lines.
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for "parent", data is (parent, parent_start, parent_end)
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:return: a generator of (start, end, kind, data)
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for hunk in self.hunks:
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if isinstance(hunk, NewText):
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end = start + len(hunk.lines)
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start = hunk.child_pos
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end = start + hunk.num_lines
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data = (hunk.parent, hunk.parent_pos, hunk.parent_pos +
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yield start, end, kind, data
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"""The number of lines in the output text"""
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for hunk in reversed(self.hunks):
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if isinstance(hunk, ParentText):
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return hunk.child_pos + hunk.num_lines + extra_n
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extra_n += len(hunk.lines)
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def is_snapshot(self):
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"""Return true of this hunk is effectively a fulltext"""
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if len(self.hunks) != 1:
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return (isinstance(self.hunks[0], NewText))
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class NewText(object):
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"""The contents of text that is introduced by this text"""
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def __init__(self, lines):
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def __eq__(self, other):
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if self.__class__ is not other.__class__:
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return (other.lines == self.lines)
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return 'NewText(%r)' % self.lines
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yield 'i %d\n' % len(self.lines)
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for line in self.lines:
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class ParentText(object):
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"""A reference to text present in a parent text"""
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def __init__(self, parent, parent_pos, child_pos, num_lines):
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self.parent_pos = parent_pos
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self.child_pos = child_pos
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self.num_lines = num_lines
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return 'ParentText(%(parent)r, %(parent_pos)r, %(child_pos)r,'\
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' %(num_lines)r)' % self.__dict__
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def __eq__(self, other):
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if self.__class__ != other.__class__:
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return (self.__dict__ == other.__dict__)
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yield 'c %(parent)d %(parent_pos)d %(child_pos)d %(num_lines)d\n'\
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class BaseVersionedFile(object):
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"""Pseudo-VersionedFile skeleton for MultiParent"""
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def __init__(self, snapshot_interval=25, max_snapshots=None):
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self._snapshots = set()
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self.snapshot_interval = snapshot_interval
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self.max_snapshots = max_snapshots
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return iter(self._parents)
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def has_version(self, version):
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return version in self._parents
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def do_snapshot(self, version_id, parent_ids):
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"""Determine whether to perform a a snapshot for this version"""
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if self.snapshot_interval is None:
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if self.max_snapshots is not None and\
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len(self._snapshots) == self.max_snapshots:
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if len(parent_ids) == 0:
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for ignored in xrange(self.snapshot_interval):
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if len(parent_ids) == 0:
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version_ids = parent_ids
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for version_id in version_ids:
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if version_id not in self._snapshots:
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parent_ids.extend(self._parents[version_id])
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def add_version(self, lines, version_id, parent_ids,
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force_snapshot=None, single_parent=False):
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"""Add a version to the versionedfile
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:param lines: The list of lines to add. Must be split on '\n'.
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:param version_id: The version_id of the version to add
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:param force_snapshot: If true, force this version to be added as a
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snapshot version. If false, force this version to be added as a
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diff. If none, determine this automatically.
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:param single_parent: If true, use a single parent, rather than
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if force_snapshot is None:
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do_snapshot = self.do_snapshot(version_id, parent_ids)
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do_snapshot = force_snapshot
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self._snapshots.add(version_id)
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diff = MultiParent([NewText(lines)])
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parent_lines = self.get_line_list(parent_ids[:1])
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parent_lines = self.get_line_list(parent_ids)
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diff = MultiParent.from_lines(lines, parent_lines)
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if diff.is_snapshot():
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self._snapshots.add(version_id)
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self.add_diff(diff, version_id, parent_ids)
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self._lines[version_id] = lines
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def get_parents(self, version_id):
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return self._parents[version_id]
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def make_snapshot(self, version_id):
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snapdiff = MultiParent([NewText(self.cache_version(version_id))])
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self.add_diff(snapdiff, version_id, self._parents[version_id])
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self._snapshots.add(version_id)
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def import_versionedfile(self, vf, snapshots, no_cache=True,
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single_parent=False, verify=False):
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"""Import all revisions of a versionedfile
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:param vf: The versionedfile to import
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:param snapshots: If provided, the revisions to make snapshots of.
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Otherwise, this will be auto-determined
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:param no_cache: If true, clear the cache after every add.
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:param single_parent: If true, omit all but one parent text, (but
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retain parent metadata).
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assert no_cache or not verify
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revisions = set(vf.versions())
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total = len(revisions)
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pb = ui.ui_factory.nested_progress_bar()
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while len(revisions) > 0:
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for revision in revisions:
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parents = vf.get_parents(revision)
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if [p for p in parents if p not in self._parents] != []:
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lines = [a + ' ' + l for a, l in
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vf.annotate_iter(revision)]
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if snapshots is None:
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force_snapshot = None
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force_snapshot = (revision in snapshots)
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self.add_version(lines, revision, parents, force_snapshot,
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assert lines == self.get_line_list([revision])[0]
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pb.update('Importing revisions',
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(total - len(revisions)) + len(added), total)
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revisions = [r for r in revisions if r not in added]
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def select_snapshots(self, vf):
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"""Determine which versions to add as snapshots"""
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for version_id in topo_iter(vf):
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potential_build_ancestors = set(vf.get_parents(version_id))
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parents = vf.get_parents(version_id)
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if len(parents) == 0:
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snapshots.add(version_id)
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build_ancestors[version_id] = set()
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for parent in vf.get_parents(version_id):
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potential_build_ancestors.update(build_ancestors[parent])
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if len(potential_build_ancestors) > self.snapshot_interval:
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snapshots.add(version_id)
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build_ancestors[version_id] = set()
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build_ancestors[version_id] = potential_build_ancestors
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def select_by_size(self, num):
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"""Select snapshots for minimum output size"""
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num -= len(self._snapshots)
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new_snapshots = self.get_size_ranking()[-num:]
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return [v for n, v in new_snapshots]
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def get_size_ranking(self):
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"""Get versions ranked by size"""
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new_snapshots = set()
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for version_id in self.versions():
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if version_id in self._snapshots:
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diff_len = self.get_diff(version_id).patch_len()
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snapshot_len = MultiParent([NewText(
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self.cache_version(version_id))]).patch_len()
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versions.append((snapshot_len - diff_len, version_id))
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def import_diffs(self, vf):
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"""Import the diffs from another pseudo-versionedfile"""
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for version_id in vf.versions():
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self.add_diff(vf.get_diff(version_id), version_id,
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vf._parents[version_id])
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def get_build_ranking(self):
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"""Return revisions sorted by how much they reduce build complexity"""
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for version_id in topo_iter(self):
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could_avoid[version_id] = set()
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if version_id not in self._snapshots:
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for parent_id in self._parents[version_id]:
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could_avoid[version_id].update(could_avoid[parent_id])
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could_avoid[version_id].update(self._parents)
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could_avoid[version_id].discard(version_id)
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for avoid_id in could_avoid[version_id]:
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referenced_by.setdefault(avoid_id, set()).add(version_id)
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available_versions = list(self.versions())
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while len(available_versions) > 0:
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available_versions.sort(key=lambda x:
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len(could_avoid[x]) *
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len(referenced_by.get(x, [])))
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selected = available_versions.pop()
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ranking.append(selected)
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for version_id in referenced_by[selected]:
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could_avoid[version_id].difference_update(
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could_avoid[selected])
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for version_id in could_avoid[selected]:
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referenced_by[version_id].difference_update(
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referenced_by[selected]
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def clear_cache(self):
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def get_line_list(self, version_ids):
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return [self.cache_version(v) for v in version_ids]
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def cache_version(self, version_id):
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return self._lines[version_id]
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diff = self.get_diff(version_id)
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reconstructor = _Reconstructor(self, self._lines, self._parents)
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reconstructor.reconstruct_version(lines, version_id)
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self._lines[version_id] = lines
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class MultiMemoryVersionedFile(BaseVersionedFile):
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"""Memory-backed pseudo-versionedfile"""
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def __init__(self, snapshot_interval=25, max_snapshots=None):
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BaseVersionedFile.__init__(self, snapshot_interval, max_snapshots)
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def add_diff(self, diff, version_id, parent_ids):
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self._diffs[version_id] = diff
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self._parents[version_id] = parent_ids
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def get_diff(self, version_id):
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return self._diffs[version_id]
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class MultiVersionedFile(BaseVersionedFile):
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"""Disk-backed pseudo-versionedfile"""
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def __init__(self, filename, snapshot_interval=25, max_snapshots=None):
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BaseVersionedFile.__init__(self, snapshot_interval, max_snapshots)
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self._filename = filename
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self._diff_offset = {}
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def get_diff(self, version_id):
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start, count = self._diff_offset[version_id]
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infile = open(self._filename + '.mpknit', 'rb')
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sio = StringIO(infile.read(count))
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zip_file = GzipFile(None, mode='rb', fileobj=sio)
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file_version_id = zip_file.readline()
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return MultiParent.from_patch(zip_file.read())
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def add_diff(self, diff, version_id, parent_ids):
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outfile = open(self._filename + '.mpknit', 'ab')
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outfile.seek(0, 2) # workaround for windows bug:
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# .tell() for files opened in 'ab' mode
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# before any write returns 0
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start = outfile.tell()
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zipfile = GzipFile(None, mode='ab', fileobj=outfile)
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zipfile.writelines(itertools.chain(
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['version %s\n' % version_id], diff.to_patch()))
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self._diff_offset[version_id] = (start, end-start)
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self._parents[version_id] = parent_ids
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os.unlink(self._filename + '.mpknit')
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if e.errno != errno.ENOENT:
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os.unlink(self._filename + '.mpidx')
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if e.errno != errno.ENOENT:
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open(self._filename + '.mpidx', 'wb').write(bencode.bencode(
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(self._parents, list(self._snapshots), self._diff_offset)))
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self._parents, snapshots, self._diff_offset = bencode.bdecode(
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open(self._filename + '.mpidx', 'rb').read())
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self._snapshots = set(snapshots)
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class _Reconstructor(object):
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"""Build a text from the diffs, ancestry graph and cached lines"""
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def __init__(self, diffs, lines, parents):
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self.parents = parents
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def reconstruct(self, lines, parent_text, version_id):
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"""Append the lines referred to by a ParentText to lines"""
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parent_id = self.parents[version_id][parent_text.parent]
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end = parent_text.parent_pos + parent_text.num_lines
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return self._reconstruct(lines, parent_id, parent_text.parent_pos,
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def _reconstruct(self, lines, req_version_id, req_start, req_end):
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"""Append lines for the requested version_id range"""
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# stack of pending range requests
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if req_start == req_end:
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pending_reqs = [(req_version_id, req_start, req_end)]
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while len(pending_reqs) > 0:
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req_version_id, req_start, req_end = pending_reqs.pop()
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# lazily allocate cursors for versions
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if req_version_id in self.lines:
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lines.extend(self.lines[req_version_id][req_start:req_end])
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start, end, kind, data, iterator = self.cursor[req_version_id]
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iterator = self.diffs.get_diff(req_version_id).range_iterator()
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start, end, kind, data = iterator.next()
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if start > req_start:
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iterator = self.diffs.get_diff(req_version_id).range_iterator()
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start, end, kind, data = iterator.next()
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# find the first hunk relevant to the request
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while end <= req_start:
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start, end, kind, data = iterator.next()
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self.cursor[req_version_id] = start, end, kind, data, iterator
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# if the hunk can't satisfy the whole request, split it in two,
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# and leave the second half for later.
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pending_reqs.append((req_version_id, end, req_end))
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lines.extend(data[req_start - start: (req_end - start)])
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# If the hunk is a ParentText, rewrite it as a range request
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# for the parent, and make it the next pending request.
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parent, parent_start, parent_end = data
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new_version_id = self.parents[req_version_id][parent]
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new_start = parent_start + req_start - start
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new_end = parent_end + req_end - end
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pending_reqs.append((new_version_id, new_start, new_end))
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def reconstruct_version(self, lines, version_id):
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length = self.diffs.get_diff(version_id).num_lines()
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return self._reconstruct(lines, version_id, 0, length)
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def gzip_string(lines):
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data_file = GzipFile(None, mode='wb', fileobj=sio)
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data_file.writelines(lines)
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return sio.getvalue()
added
removed
bzrlib/multiparent.py
