3
# Copyright (C) 2005 Canonical Ltd
5
# This program is free software; you can redistribute it and/or modify
6
# it under the terms of the GNU General Public License as published by
7
# the Free Software Foundation; either version 2 of the License, or
8
# (at your option) any later version.
10
# This program is distributed in the hope that it will be useful,
11
# but WITHOUT ANY WARRANTY; without even the implied warranty of
12
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13
# GNU General Public License for more details.
15
# You should have received a copy of the GNU General Public License
16
# along with this program; if not, write to the Free Software
17
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19
# Author: Martin Pool <mbp@canonical.com>
22
"""Weave - storage of related text file versions"""
24
# before intset (r923) 2000 versions in 41.5s
25
# with intset (r926) 2000 versions in 93s !!!
26
# better to just use plain sets.
28
# making _extract build and return a list, rather than being a generator
31
# with python -O, r923 does 2000 versions in 36.87s
33
# with optimizations to avoid mutating lists - 35.75! I guess copying
34
# all the elements every time costs more than the small manipulations.
35
# a surprisingly small change.
37
# r931, which avoids using a generator for extract, does 36.98s
39
# with memoized inclusions, takes 41.49s; not very good
41
# with slots, takes 37.35s; without takes 39.16, a bit surprising
43
# with the delta calculation mixed in with the add method, rather than
44
# separated, takes 36.78s
46
# with delta folded in and mutation of the list, 36.13s
48
# with all this and simplification of add code, 33s
51
# TODO: Perhaps have copy method for Weave instances?
53
# XXX: If we do weaves this way, will a merge still behave the same
54
# way if it's done in a different order? That's a pretty desirable
57
# TODO: Nothing here so far assumes the lines are really \n newlines,
58
# rather than being split up in some other way. We could accomodate
59
# binaries, perhaps by naively splitting on \n or perhaps using
60
# something like a rolling checksum.
62
# TODO: Track version names as well as indexes.
64
# TODO: End marker for each version so we can stop reading?
66
# TODO: Check that no insertion occurs inside a deletion that was
67
# active in the version of the insertion.
69
# TODO: In addition to the SHA-1 check, perhaps have some code that
70
# checks structural constraints of the weave: ie that insertions are
71
# properly nested, that there is no text outside of an insertion, that
72
# insertions or deletions are not repeated, etc.
74
# TODO: Parallel-extract that passes back each line along with a
75
# description of which revisions include it. Nice for checking all
81
class WeaveError(Exception):
82
"""Exception in processing weave"""
85
class WeaveFormatError(WeaveError):
86
"""Weave invariant violated"""
90
"""weave - versioned text file storage.
92
A Weave manages versions of line-based text files, keeping track
93
of the originating version for each line.
95
To clients the "lines" of the file are represented as a list of strings.
96
These strings will typically have terminal newline characters, but
97
this is not required. In particular files commonly do not have a newline
98
at the end of the file.
100
Texts can be identified in either of two ways:
102
* a nonnegative index number.
104
* a version-id string.
106
Typically the index number will be valid only inside this weave and
107
the version-id is used to reference it in the larger world.
109
The weave is represented as a list mixing edit instructions and
110
literal text. Each entry in _weave can be either a string (or
111
unicode), or a tuple. If a string, it means that the given line
112
should be output in the currently active revisions.
114
If a tuple, it gives a processing instruction saying in which
115
revisions the enclosed lines are active. The tuple has the form
116
(instruction, version).
118
The instruction can be '{' or '}' for an insertion block, and '['
119
and ']' for a deletion block respectively. The version is the
120
integer version index. There is no replace operator, only deletes
125
* A later version can delete lines that were introduced by any
126
number of ancestor versions; this implies that deletion
127
instructions can span insertion blocks without regard to the
128
insertion block's nesting.
130
* Similarly, deletions need not be properly nested with regard to
131
each other, because they might have been generated by
132
independent revisions.
134
* Insertions are always made by inserting a new bracketed block
135
into a single point in the previous weave. This implies they
136
can nest but not overlap, and the nesting must always have later
137
insertions on the inside.
139
* It doesn't seem very useful to have an active insertion
140
inside an inactive insertion, but it might happen.
142
* Therefore, all instructions are always"considered"; that
143
is passed onto and off the stack. An outer inactive block
144
doesn't disable an inner block.
146
* Lines are enabled if the most recent enclosing insertion is
147
active and none of the enclosing deletions are active.
149
* There is no point having a deletion directly inside its own
150
insertion; you might as well just not write it. And there
151
should be no way to get an earlier version deleting a later
155
Text of the weave; list of control instruction tuples and strings.
158
List of parents, indexed by version number.
159
It is only necessary to store the minimal set of parents for
160
each version; the parent's parents are implied.
163
List of hex SHA-1 of each version, or None if not recorded.
166
__slots__ = ['_weave', '_parents', '_sha1s']
174
def __eq__(self, other):
175
if not isinstance(other, Weave):
177
return self._parents == other._parents \
178
and self._weave == other._weave
181
def __ne__(self, other):
182
return not self.__eq__(other)
185
def add(self, parents, text):
186
"""Add a single text on top of the weave.
188
Returns the index number of the newly added version.
191
List or set of direct parent version numbers.
194
Sequence of lines to be added in the new version."""
196
self._check_versions(parents)
197
## self._check_lines(text)
198
new_version = len(self._parents)
206
# if we abort after here the weave will be corrupt
207
self._parents.append(frozenset(parents))
208
self._sha1s.append(sha1)
212
# special case; adding with no parents revision; can do
213
# this more quickly by just appending unconditionally.
214
# even more specially, if we're adding an empty text we
215
# need do nothing at all.
217
self._weave.append(('{', new_version))
218
self._weave.extend(text)
219
self._weave.append(('}', new_version))
223
if len(parents) == 1:
224
pv = list(parents)[0]
225
if sha1 == self._sha1s[pv]:
226
# special case: same as the single parent
230
ancestors = self.inclusions(parents)
234
# basis a list of (origin, lineno, line)
237
for origin, lineno, line in self._extract(ancestors):
238
basis_lineno.append(lineno)
239
basis_lines.append(line)
241
# another small special case: a merge, producing the same text as auto-merge
242
if text == basis_lines:
245
# add a sentinal, because we can also match against the final line
246
basis_lineno.append(len(self._weave))
248
# XXX: which line of the weave should we really consider
249
# matches the end of the file? the current code says it's the
250
# last line of the weave?
252
#print 'basis_lines:', basis_lines
253
#print 'new_lines: ', lines
255
from difflib import SequenceMatcher
256
s = SequenceMatcher(None, basis_lines, text)
258
# offset gives the number of lines that have been inserted
259
# into the weave up to the current point; if the original edit instruction
260
# says to change line A then we actually change (A+offset)
263
for tag, i1, i2, j1, j2 in s.get_opcodes():
264
# i1,i2 are given in offsets within basis_lines; we need to map them
265
# back to offsets within the entire weave
266
#print 'raw match', tag, i1, i2, j1, j2
270
i1 = basis_lineno[i1]
271
i2 = basis_lineno[i2]
273
assert 0 <= j1 <= j2 <= len(text)
275
#print tag, i1, i2, j1, j2
277
# the deletion and insertion are handled separately.
278
# first delete the region.
280
self._weave.insert(i1+offset, ('[', new_version))
281
self._weave.insert(i2+offset+1, (']', new_version))
285
# there may have been a deletion spanning up to
286
# i2; we want to insert after this region to make sure
287
# we don't destroy ourselves
289
self._weave[i:i] = ([('{', new_version)]
291
+ [('}', new_version)])
292
offset += 2 + (j2 - j1)
297
def inclusions(self, versions):
298
"""Return set of all ancestors of given version(s)."""
304
# include all its parents
305
i.update(self._parents[v])
309
raise ValueError("version %d not present in weave" % v)
312
def minimal_parents(self, version):
313
"""Find the minimal set of parents for the version."""
314
included = self._parents[version]
319
li.sort(reverse=True)
327
gotit.update(self.inclusions(pv))
329
assert mininc[0] >= 0
330
assert mininc[-1] < version
335
def _check_lines(self, text):
336
if not isinstance(text, list):
337
raise ValueError("text should be a list, not %s" % type(text))
340
if not isinstance(l, basestring):
341
raise ValueError("text line should be a string or unicode, not %s"
346
def _check_versions(self, indexes):
347
"""Check everything in the sequence of indexes is valid"""
352
raise IndexError("invalid version number %r" % i)
355
def annotate(self, index):
356
return list(self.annotate_iter(index))
359
def annotate_iter(self, version):
360
"""Yield list of (index-id, line) pairs for the specified version.
362
The index indicates when the line originated in the weave."""
363
for origin, lineno, text in self._extract([version]):
371
(lineno, insert, deletes, text)
372
for each literal line.
378
lineno = 0 # line of weave, 0-based
380
for l in self._weave:
381
if isinstance(l, tuple):
394
raise WeaveFormatError('unexpected instruction %r'
397
assert isinstance(l, basestring)
399
yield lineno, istack[-1], dset, l
404
def _extract(self, versions):
405
"""Yield annotation of lines in included set.
407
Yields a sequence of tuples (origin, lineno, text), where
408
origin is the origin version, lineno the index in the weave,
409
and text the text of the line.
411
The set typically but not necessarily corresponds to a version.
413
included = self.inclusions(versions)
418
lineno = 0 # line of weave, 0-based
424
WFE = WeaveFormatError
426
for l in self._weave:
427
if isinstance(l, tuple):
431
assert v not in istack
446
assert isinstance(l, basestring)
448
isactive = (not dset) and istack and (istack[-1] in included)
450
result.append((istack[-1], lineno, l))
454
raise WFE("unclosed insertion blocks at end of weave",
457
raise WFE("unclosed deletion blocks at end of weave",
464
def get_iter(self, version):
465
"""Yield lines for the specified version."""
466
for origin, lineno, line in self._extract([version]):
470
def get(self, index):
471
return list(self.get_iter(index))
474
def mash_iter(self, included):
475
"""Return composed version of multiple included versions."""
476
for origin, lineno, text in self._extract(included):
480
def dump(self, to_file):
481
from pprint import pprint
482
print >>to_file, "Weave._weave = ",
483
pprint(self._weave, to_file)
484
print >>to_file, "Weave._parents = ",
485
pprint(self._parents, to_file)
489
def numversions(self):
490
l = len(self._parents)
491
assert l == len(self._sha1s)
496
return self.numversions()
499
def check(self, progress_bar=None):
500
# check no circular inclusions
501
for version in range(self.numversions()):
502
inclusions = list(self._parents[version])
505
if inclusions[-1] >= version:
506
raise WeaveFormatError("invalid included version %d for index %d"
507
% (inclusions[-1], version))
509
# try extracting all versions; this is a bit slow and parallel
510
# extraction could be used
512
nv = self.numversions()
513
for version in range(nv):
515
progress_bar.update('checking text', version, nv)
517
for l in self.get_iter(version):
520
expected = self._sha1s[version]
522
raise WeaveError("mismatched sha1 for version %d; "
523
"got %s, expected %s"
524
% (version, hd, expected))
526
# TODO: check insertions are properly nested, that there are
527
# no lines outside of insertion blocks, that deletions are
528
# properly paired, etc.
532
def merge(self, merge_versions):
533
"""Automerge and mark conflicts between versions.
535
This returns a sequence, each entry describing alternatives
536
for a chunk of the file. Each of the alternatives is given as
539
If there is a chunk of the file where there's no diagreement,
540
only one alternative is given.
543
# approach: find the included versions common to all the
545
raise NotImplementedError()
549
def _delta(self, included, lines):
550
"""Return changes from basis to new revision.
552
The old text for comparison is the union of included revisions.
554
This is used in inserting a new text.
556
Delta is returned as a sequence of
557
(weave1, weave2, newlines).
559
This indicates that weave1:weave2 of the old weave should be
560
replaced by the sequence of lines in newlines. Note that
561
these line numbers are positions in the total weave and don't
562
correspond to the lines in any extracted version, or even the
563
extracted union of included versions.
565
If line1=line2, this is a pure insert; if newlines=[] this is a
566
pure delete. (Similar to difflib.)
571
def plan_merge(self, ver_a, ver_b):
572
"""Return pseudo-annotation indicating how the two versions merge.
574
This is computed between versions a and b and their common
577
Weave lines present in none of them are skipped entirely.
579
inc_a = self.inclusions([ver_a])
580
inc_b = self.inclusions([ver_b])
581
inc_c = inc_a & inc_b
583
for lineno, insert, deleteset, line in self._walk():
584
if deleteset & inc_c:
585
# killed in parent; can't be in either a or b
586
# not relevant to our work
587
yield 'killed-base', line
588
elif insert in inc_c:
589
# was inserted in base
590
killed_a = bool(deleteset & inc_a)
591
killed_b = bool(deleteset & inc_b)
592
if killed_a and killed_b:
593
yield 'killed-both', line
595
yield 'killed-a', line
597
yield 'killed-b', line
599
yield 'unchanged', line
600
elif insert in inc_a:
601
if deleteset & inc_a:
602
yield 'ghost-a', line
606
elif insert in inc_b:
607
if deleteset & inc_b:
608
yield 'ghost-b', line
612
# not in either revision
613
yield 'irrelevant', line
615
yield 'unchanged', '' # terminator
619
def weave_merge(self, plan):
624
for state, line in plan:
625
if state == 'unchanged' or state == 'killed-both':
626
# resync and flush queued conflicts changes if any
627
if not lines_a and not lines_b:
629
elif ch_a and not ch_b:
631
for l in lines_a: yield l
632
elif ch_b and not ch_a:
633
for l in lines_b: yield l
634
elif lines_a == lines_b:
635
for l in lines_a: yield l
638
for l in lines_a: yield l
640
for l in lines_b: yield l
647
if state == 'unchanged':
650
elif state == 'killed-a':
653
elif state == 'killed-b':
656
elif state == 'new-a':
659
elif state == 'new-b':
663
assert state in ('irrelevant', 'ghost-a', 'ghost-b', 'killed-base',
674
"""Show some text information about the weave."""
675
print '%6s %40s %20s' % ('ver', 'sha1', 'parents')
676
for i in (6, 40, 20):
679
for i in range(w.numversions()):
681
print '%6d %40s %s' % (i, sha1, ' '.join(map(str, w._parents[i])))
685
def weave_stats(weave_file):
686
from bzrlib.progress import ProgressBar
687
from bzrlib.weavefile import read_weave
691
wf = file(weave_file, 'rb')
693
# FIXME: doesn't work on pipes
694
weave_size = wf.tell()
698
for i in range(vers):
699
pb.update('checking sizes', i, vers)
700
for line in w.get_iter(i):
705
print 'versions %9d' % vers
706
print 'weave file %9d bytes' % weave_size
707
print 'total contents %9d bytes' % total
708
print 'compression ratio %9.2fx' % (float(total) / float(weave_size))
713
print """bzr weave tool
715
Experimental tool for weave algorithm.
719
Create an empty weave file
720
weave get WEAVEFILE VERSION
721
Write out specified version.
722
weave check WEAVEFILE
723
Check consistency of all versions.
725
Display table of contents.
726
weave add WEAVEFILE [BASE...] < NEWTEXT
727
Add NEWTEXT, with specified parent versions.
728
weave annotate WEAVEFILE VERSION
729
Display origin of each line.
730
weave mash WEAVEFILE VERSION...
731
Display composite of all selected versions.
732
weave merge WEAVEFILE VERSION1 VERSION2 > OUT
733
Auto-merge two versions and display conflicts.
737
% weave init foo.weave
739
% weave add foo.weave < foo.txt
742
(create updated version)
744
% weave get foo.weave 0 | diff -u - foo.txt
745
% weave add foo.weave 0 < foo.txt
748
% weave get foo.weave 0 > foo.txt (create forked version)
750
% weave add foo.weave 0 < foo.txt
753
% weave merge foo.weave 1 2 > foo.txt (merge them)
754
% vi foo.txt (resolve conflicts)
755
% weave add foo.weave 1 2 < foo.txt (commit merged version)
764
from weavefile import write_weave, read_weave
765
from bzrlib.progress import ProgressBar
773
return read_weave(file(argv[2], 'rb'))
779
# at the moment, based on everything in the file
780
parents = map(int, argv[3:])
781
lines = sys.stdin.readlines()
782
ver = w.add(parents, lines)
783
write_weave(w, file(argv[2], 'wb'))
784
print 'added version %d' % ver
787
if os.path.exists(fn):
788
raise IOError("file exists")
790
write_weave(w, file(fn, 'wb'))
791
elif cmd == 'get': # get one version
793
sys.stdout.writelines(w.get_iter(int(argv[3])))
795
elif cmd == 'mash': # get composite
797
sys.stdout.writelines(w.mash_iter(map(int, argv[3:])))
799
elif cmd == 'annotate':
801
# newline is added to all lines regardless; too hard to get
802
# reasonable formatting otherwise
804
for origin, text in w.annotate(int(argv[3])):
805
text = text.rstrip('\r\n')
807
print ' | %s' % (text)
809
print '%5d | %s' % (origin, text)
823
print '%d versions ok' % w.numversions()
825
elif cmd == 'inclusions':
827
print ' '.join(map(str, w.inclusions([int(argv[3])])))
829
elif cmd == 'parents':
831
print ' '.join(map(str, w._parents[int(argv[3])]))
833
elif cmd == 'plan-merge':
835
for state, line in w.plan_merge(int(argv[3]), int(argv[4])):
837
print '%14s | %s' % (state, line),
841
p = w.plan_merge(int(argv[3]), int(argv[4]))
842
sys.stdout.writelines(w.weave_merge(p))
844
elif cmd == 'mash-merge':
850
v1, v2 = map(int, argv[3:5])
852
basis = w.inclusions([v1]).intersection(w.inclusions([v2]))
854
base_lines = list(w.mash_iter(basis))
855
a_lines = list(w.get(v1))
856
b_lines = list(w.get(v2))
858
from bzrlib.merge3 import Merge3
859
m3 = Merge3(base_lines, a_lines, b_lines)
861
name_a = 'version %d' % v1
862
name_b = 'version %d' % v2
863
sys.stdout.writelines(m3.merge_lines(name_a=name_a, name_b=name_b))
865
raise ValueError('unknown command %r' % cmd)
868
if __name__ == '__main__':
870
sys.exit(main(sys.argv))