# Copyright (C) 2007-2011 Canonical Ltd
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
from __future__ import absolute_import
from bzrlib.lazy_import import lazy_import
lazy_import(globals(), """
import errno
import gzip
import itertools
import os
from StringIO import StringIO
from bzrlib import (
bencode,
errors,
patiencediff,
ui,
)
""")
def topo_iter_keys(vf, keys=None):
if keys is None:
keys = vf.keys()
parents = vf.get_parent_map(keys)
return _topo_iter(parents, keys)
def topo_iter(vf, versions=None):
if versions is None:
versions = vf.versions()
parents = vf.get_parent_map(versions)
return _topo_iter(parents, versions)
def _topo_iter(parents, versions):
seen = set()
descendants = {}
def pending_parents(version):
if parents[version] is None:
return []
return [v for v in parents[version] if v in versions and
v not in seen]
for version_id in versions:
if parents[version_id] is None:
# parentless
continue
for parent_id in parents[version_id]:
descendants.setdefault(parent_id, []).append(version_id)
cur = [v for v in versions if len(pending_parents(v)) == 0]
while len(cur) > 0:
next = []
for version_id in cur:
if version_id in seen:
continue
if len(pending_parents(version_id)) != 0:
continue
next.extend(descendants.get(version_id, []))
yield version_id
seen.add(version_id)
cur = next
class MultiParent(object):
"""A multi-parent diff"""
__slots__ = ['hunks']
def __init__(self, hunks=None):
if hunks is not None:
self.hunks = hunks
else:
self.hunks = []
def __repr__(self):
return "MultiParent(%r)" % self.hunks
def __eq__(self, other):
if self.__class__ is not other.__class__:
return False
return (self.hunks == other.hunks)
@staticmethod
def from_lines(text, parents=(), left_blocks=None):
"""Produce a MultiParent from a list of lines and parents"""
def compare(parent):
matcher = patiencediff.PatienceSequenceMatcher(None, parent,
text)
return matcher.get_matching_blocks()
if len(parents) > 0:
if left_blocks is None:
left_blocks = compare(parents[0])
parent_comparisons = [left_blocks] + [compare(p) for p in
parents[1:]]
else:
parent_comparisons = []
cur_line = 0
new_text = NewText([])
parent_text = []
block_iter = [iter(i) for i in parent_comparisons]
diff = MultiParent([])
def next_block(p):
try:
return block_iter[p].next()
except StopIteration:
return None
cur_block = [next_block(p) for p, i in enumerate(block_iter)]
while cur_line < len(text):
best_match = None
for p, block in enumerate(cur_block):
if block is None:
continue
i, j, n = block
while j + n <= cur_line:
block = cur_block[p] = next_block(p)
if block is None:
break
i, j, n = block
if block is None:
continue
if j > cur_line:
continue
offset = cur_line - j
i += offset
j = cur_line
n -= offset
if n == 0:
continue
if best_match is None or n > best_match.num_lines:
best_match = ParentText(p, i, j, n)
if best_match is None:
new_text.lines.append(text[cur_line])
cur_line += 1
else:
if len(new_text.lines) > 0:
diff.hunks.append(new_text)
new_text = NewText([])
diff.hunks.append(best_match)
cur_line += best_match.num_lines
if len(new_text.lines) > 0:
diff.hunks.append(new_text)
return diff
def get_matching_blocks(self, parent, parent_len):
for hunk in self.hunks:
if not isinstance(hunk, ParentText) or hunk.parent != parent:
continue
yield (hunk.parent_pos, hunk.child_pos, hunk.num_lines)
yield parent_len, self.num_lines(), 0
def to_lines(self, parents=()):
"""Contruct a fulltext from this diff and its parents"""
mpvf = MultiMemoryVersionedFile()
for num, parent in enumerate(parents):
mpvf.add_version(StringIO(parent).readlines(), num, [])
mpvf.add_diff(self, 'a', range(len(parents)))
return mpvf.get_line_list(['a'])[0]
@classmethod
def from_texts(cls, text, parents=()):
"""Produce a MultiParent from a text and list of parent text"""
return cls.from_lines(StringIO(text).readlines(),
[StringIO(p).readlines() for p in parents])
def to_patch(self):
"""Yield text lines for a patch"""
for hunk in self.hunks:
for line in hunk.to_patch():
yield line
def patch_len(self):
return len(''.join(self.to_patch()))
def zipped_patch_len(self):
return len(gzip_string(self.to_patch()))
@classmethod
def from_patch(cls, text):
"""Create a MultiParent from its string form"""
return cls._from_patch(StringIO(text))
@staticmethod
def _from_patch(lines):
"""This is private because it is essential to split lines on \n only"""
line_iter = iter(lines)
hunks = []
cur_line = None
while(True):
try:
cur_line = line_iter.next()
except StopIteration:
break
if cur_line[0] == 'i':
num_lines = int(cur_line.split(' ')[1])
hunk_lines = [line_iter.next() for x in xrange(num_lines)]
hunk_lines[-1] = hunk_lines[-1][:-1]
hunks.append(NewText(hunk_lines))
elif cur_line[0] == '\n':
hunks[-1].lines[-1] += '\n'
else:
if not (cur_line[0] == 'c'):
raise AssertionError(cur_line[0])
parent, parent_pos, child_pos, num_lines =\
[int(v) for v in cur_line.split(' ')[1:]]
hunks.append(ParentText(parent, parent_pos, child_pos,
num_lines))
return MultiParent(hunks)
def range_iterator(self):
"""Iterate through the hunks, with range indicated
kind is "new" or "parent".
for "new", data is a list of lines.
for "parent", data is (parent, parent_start, parent_end)
:return: a generator of (start, end, kind, data)
"""
start = 0
for hunk in self.hunks:
if isinstance(hunk, NewText):
kind = 'new'
end = start + len(hunk.lines)
data = hunk.lines
else:
kind = 'parent'
start = hunk.child_pos
end = start + hunk.num_lines
data = (hunk.parent, hunk.parent_pos, hunk.parent_pos +
hunk.num_lines)
yield start, end, kind, data
start = end
def num_lines(self):
"""The number of lines in the output text"""
extra_n = 0
for hunk in reversed(self.hunks):
if isinstance(hunk, ParentText):
return hunk.child_pos + hunk.num_lines + extra_n
extra_n += len(hunk.lines)
return extra_n
def is_snapshot(self):
"""Return true of this hunk is effectively a fulltext"""
if len(self.hunks) != 1:
return False
return (isinstance(self.hunks[0], NewText))
class NewText(object):
"""The contents of text that is introduced by this text"""
__slots__ = ['lines']
def __init__(self, lines):
self.lines = lines
def __eq__(self, other):
if self.__class__ is not other.__class__:
return False
return (other.lines == self.lines)
def __repr__(self):
return 'NewText(%r)' % self.lines
def to_patch(self):
yield 'i %d\n' % len(self.lines)
for line in self.lines:
yield line
yield '\n'
class ParentText(object):
"""A reference to text present in a parent text"""
__slots__ = ['parent', 'parent_pos', 'child_pos', 'num_lines']
def __init__(self, parent, parent_pos, child_pos, num_lines):
self.parent = parent
self.parent_pos = parent_pos
self.child_pos = child_pos
self.num_lines = num_lines
def _as_dict(self):
return dict(parent=self.parent, parent_pos=self.parent_pos,
child_pos=self.child_pos, num_lines=self.num_lines)
def __repr__(self):
return ('ParentText(%(parent)r, %(parent_pos)r, %(child_pos)r,'
' %(num_lines)r)' % self._as_dict())
def __eq__(self, other):
if self.__class__ is not other.__class__:
return False
return self._as_dict() == other._as_dict()
def to_patch(self):
yield ('c %(parent)d %(parent_pos)d %(child_pos)d %(num_lines)d\n'
% self._as_dict())
class BaseVersionedFile(object):
"""Pseudo-VersionedFile skeleton for MultiParent"""
def __init__(self, snapshot_interval=25, max_snapshots=None):
self._lines = {}
self._parents = {}
self._snapshots = set()
self.snapshot_interval = snapshot_interval
self.max_snapshots = max_snapshots
def versions(self):
return iter(self._parents)
def has_version(self, version):
return version in self._parents
def do_snapshot(self, version_id, parent_ids):
"""Determine whether to perform a snapshot for this version"""
if self.snapshot_interval is None:
return False
if self.max_snapshots is not None and\
len(self._snapshots) == self.max_snapshots:
return False
if len(parent_ids) == 0:
return True
for ignored in xrange(self.snapshot_interval):
if len(parent_ids) == 0:
return False
version_ids = parent_ids
parent_ids = []
for version_id in version_ids:
if version_id not in self._snapshots:
parent_ids.extend(self._parents[version_id])
else:
return True
def add_version(self, lines, version_id, parent_ids,
force_snapshot=None, single_parent=False):
"""Add a version to the versionedfile
:param lines: The list of lines to add. Must be split on '\n'.
:param version_id: The version_id of the version to add
:param force_snapshot: If true, force this version to be added as a
snapshot version. If false, force this version to be added as a
diff. If none, determine this automatically.
:param single_parent: If true, use a single parent, rather than
multiple parents.
"""
if force_snapshot is None:
do_snapshot = self.do_snapshot(version_id, parent_ids)
else:
do_snapshot = force_snapshot
if do_snapshot:
self._snapshots.add(version_id)
diff = MultiParent([NewText(lines)])
else:
if single_parent:
parent_lines = self.get_line_list(parent_ids[:1])
else:
parent_lines = self.get_line_list(parent_ids)
diff = MultiParent.from_lines(lines, parent_lines)
if diff.is_snapshot():
self._snapshots.add(version_id)
self.add_diff(diff, version_id, parent_ids)
self._lines[version_id] = lines
def get_parents(self, version_id):
return self._parents[version_id]
def make_snapshot(self, version_id):
snapdiff = MultiParent([NewText(self.cache_version(version_id))])
self.add_diff(snapdiff, version_id, self._parents[version_id])
self._snapshots.add(version_id)
def import_versionedfile(self, vf, snapshots, no_cache=True,
single_parent=False, verify=False):
"""Import all revisions of a versionedfile
:param vf: The versionedfile to import
:param snapshots: If provided, the revisions to make snapshots of.
Otherwise, this will be auto-determined
:param no_cache: If true, clear the cache after every add.
:param single_parent: If true, omit all but one parent text, (but
retain parent metadata).
"""
if not (no_cache or not verify):
raise ValueError()
revisions = set(vf.versions())
total = len(revisions)
pb = ui.ui_factory.nested_progress_bar()
try:
while len(revisions) > 0:
added = set()
for revision in revisions:
parents = vf.get_parents(revision)
if [p for p in parents if p not in self._parents] != []:
continue
lines = [a + ' ' + l for a, l in
vf.annotate(revision)]
if snapshots is None:
force_snapshot = None
else:
force_snapshot = (revision in snapshots)
self.add_version(lines, revision, parents, force_snapshot,
single_parent)
added.add(revision)
if no_cache:
self.clear_cache()
vf.clear_cache()
if verify:
if not (lines == self.get_line_list([revision])[0]):
raise AssertionError()
self.clear_cache()
pb.update(gettext('Importing revisions'),
(total - len(revisions)) + len(added), total)
revisions = [r for r in revisions if r not in added]
finally:
pb.finished()
def select_snapshots(self, vf):
"""Determine which versions to add as snapshots"""
build_ancestors = {}
descendants = {}
snapshots = set()
for version_id in topo_iter(vf):
potential_build_ancestors = set(vf.get_parents(version_id))
parents = vf.get_parents(version_id)
if len(parents) == 0:
snapshots.add(version_id)
build_ancestors[version_id] = set()
else:
for parent in vf.get_parents(version_id):
potential_build_ancestors.update(build_ancestors[parent])
if len(potential_build_ancestors) > self.snapshot_interval:
snapshots.add(version_id)
build_ancestors[version_id] = set()
else:
build_ancestors[version_id] = potential_build_ancestors
return snapshots
def select_by_size(self, num):
"""Select snapshots for minimum output size"""
num -= len(self._snapshots)
new_snapshots = self.get_size_ranking()[-num:]
return [v for n, v in new_snapshots]
def get_size_ranking(self):
"""Get versions ranked by size"""
versions = []
new_snapshots = set()
for version_id in self.versions():
if version_id in self._snapshots:
continue
diff_len = self.get_diff(version_id).patch_len()
snapshot_len = MultiParent([NewText(
self.cache_version(version_id))]).patch_len()
versions.append((snapshot_len - diff_len, version_id))
versions.sort()
return versions
def import_diffs(self, vf):
"""Import the diffs from another pseudo-versionedfile"""
for version_id in vf.versions():
self.add_diff(vf.get_diff(version_id), version_id,
vf._parents[version_id])
def get_build_ranking(self):
"""Return revisions sorted by how much they reduce build complexity"""
could_avoid = {}
referenced_by = {}
for version_id in topo_iter(self):
could_avoid[version_id] = set()
if version_id not in self._snapshots:
for parent_id in self._parents[version_id]:
could_avoid[version_id].update(could_avoid[parent_id])
could_avoid[version_id].update(self._parents)
could_avoid[version_id].discard(version_id)
for avoid_id in could_avoid[version_id]:
referenced_by.setdefault(avoid_id, set()).add(version_id)
available_versions = list(self.versions())
ranking = []
while len(available_versions) > 0:
available_versions.sort(key=lambda x:
len(could_avoid[x]) *
len(referenced_by.get(x, [])))
selected = available_versions.pop()
ranking.append(selected)
for version_id in referenced_by[selected]:
could_avoid[version_id].difference_update(
could_avoid[selected])
for version_id in could_avoid[selected]:
referenced_by[version_id].difference_update(
referenced_by[selected]
)
return ranking
def clear_cache(self):
self._lines.clear()
def get_line_list(self, version_ids):
return [self.cache_version(v) for v in version_ids]
def cache_version(self, version_id):
try:
return self._lines[version_id]
except KeyError:
pass
diff = self.get_diff(version_id)
lines = []
reconstructor = _Reconstructor(self, self._lines, self._parents)
reconstructor.reconstruct_version(lines, version_id)
self._lines[version_id] = lines
return lines
class MultiMemoryVersionedFile(BaseVersionedFile):
"""Memory-backed pseudo-versionedfile"""
def __init__(self, snapshot_interval=25, max_snapshots=None):
BaseVersionedFile.__init__(self, snapshot_interval, max_snapshots)
self._diffs = {}
def add_diff(self, diff, version_id, parent_ids):
self._diffs[version_id] = diff
self._parents[version_id] = parent_ids
def get_diff(self, version_id):
try:
return self._diffs[version_id]
except KeyError:
raise errors.RevisionNotPresent(version_id, self)
def destroy(self):
self._diffs = {}
class MultiVersionedFile(BaseVersionedFile):
"""Disk-backed pseudo-versionedfile"""
def __init__(self, filename, snapshot_interval=25, max_snapshots=None):
BaseVersionedFile.__init__(self, snapshot_interval, max_snapshots)
self._filename = filename
self._diff_offset = {}
def get_diff(self, version_id):
start, count = self._diff_offset[version_id]
infile = open(self._filename + '.mpknit', 'rb')
try:
infile.seek(start)
sio = StringIO(infile.read(count))
finally:
infile.close()
zip_file = gzip.GzipFile(None, mode='rb', fileobj=sio)
try:
file_version_id = zip_file.readline()
content = zip_file.read()
return MultiParent.from_patch(content)
finally:
zip_file.close()
def add_diff(self, diff, version_id, parent_ids):
outfile = open(self._filename + '.mpknit', 'ab')
try:
outfile.seek(0, 2) # workaround for windows bug:
# .tell() for files opened in 'ab' mode
# before any write returns 0
start = outfile.tell()
try:
zipfile = gzip.GzipFile(None, mode='ab', fileobj=outfile)
zipfile.writelines(itertools.chain(
['version %s\n' % version_id], diff.to_patch()))
finally:
zipfile.close()
end = outfile.tell()
finally:
outfile.close()
self._diff_offset[version_id] = (start, end-start)
self._parents[version_id] = parent_ids
def destroy(self):
try:
os.unlink(self._filename + '.mpknit')
except OSError, e:
if e.errno != errno.ENOENT:
raise
try:
os.unlink(self._filename + '.mpidx')
except OSError, e:
if e.errno != errno.ENOENT:
raise
def save(self):
open(self._filename + '.mpidx', 'wb').write(bencode.bencode(
(self._parents, list(self._snapshots), self._diff_offset)))
def load(self):
self._parents, snapshots, self._diff_offset = bencode.bdecode(
open(self._filename + '.mpidx', 'rb').read())
self._snapshots = set(snapshots)
class _Reconstructor(object):
"""Build a text from the diffs, ancestry graph and cached lines"""
def __init__(self, diffs, lines, parents):
self.diffs = diffs
self.lines = lines
self.parents = parents
self.cursor = {}
def reconstruct(self, lines, parent_text, version_id):
"""Append the lines referred to by a ParentText to lines"""
parent_id = self.parents[version_id][parent_text.parent]
end = parent_text.parent_pos + parent_text.num_lines
return self._reconstruct(lines, parent_id, parent_text.parent_pos,
end)
def _reconstruct(self, lines, req_version_id, req_start, req_end):
"""Append lines for the requested version_id range"""
# stack of pending range requests
if req_start == req_end:
return
pending_reqs = [(req_version_id, req_start, req_end)]
while len(pending_reqs) > 0:
req_version_id, req_start, req_end = pending_reqs.pop()
# lazily allocate cursors for versions
if req_version_id in self.lines:
lines.extend(self.lines[req_version_id][req_start:req_end])
continue
try:
start, end, kind, data, iterator = self.cursor[req_version_id]
except KeyError:
iterator = self.diffs.get_diff(req_version_id).range_iterator()
start, end, kind, data = iterator.next()
if start > req_start:
iterator = self.diffs.get_diff(req_version_id).range_iterator()
start, end, kind, data = iterator.next()
# find the first hunk relevant to the request
while end <= req_start:
start, end, kind, data = iterator.next()
self.cursor[req_version_id] = start, end, kind, data, iterator
# if the hunk can't satisfy the whole request, split it in two,
# and leave the second half for later.
if req_end > end:
pending_reqs.append((req_version_id, end, req_end))
req_end = end
if kind == 'new':
lines.extend(data[req_start - start: (req_end - start)])
else:
# If the hunk is a ParentText, rewrite it as a range request
# for the parent, and make it the next pending request.
parent, parent_start, parent_end = data
new_version_id = self.parents[req_version_id][parent]
new_start = parent_start + req_start - start
new_end = parent_end + req_end - end
pending_reqs.append((new_version_id, new_start, new_end))
def reconstruct_version(self, lines, version_id):
length = self.diffs.get_diff(version_id).num_lines()
return self._reconstruct(lines, version_id, 0, length)
def gzip_string(lines):
sio = StringIO()
data_file = gzip.GzipFile(None, mode='wb', fileobj=sio)
data_file.writelines(lines)
data_file.close()
return sio.getvalue()