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#! /usr/bin/python
# Copyright (C) 2005 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
# Author: Martin Pool <mbp@canonical.com>
"""Weave - storage of related text file versions"""
# before intset (r923) 2000 versions in 41.5s
# with intset (r926) 2000 versions in 93s !!!
# better to just use plain sets.
# making _extract build and return a list, rather than being a generator
# takes 37.94s
# TODO: Perhaps have copy method for Weave instances?
# XXX: If we do weaves this way, will a merge still behave the same
# way if it's done in a different order? That's a pretty desirable
# property.
# TODO: Nothing here so far assumes the lines are really \n newlines,
# rather than being split up in some other way. We could accomodate
# binaries, perhaps by naively splitting on \n or perhaps using
# something like a rolling checksum.
# TODO: Track version names as well as indexes.
# TODO: End marker for each version so we can stop reading?
# TODO: Check that no insertion occurs inside a deletion that was
# active in the version of the insertion.
# TODO: In addition to the SHA-1 check, perhaps have some code that
# checks structural constraints of the weave: ie that insertions are
# properly nested, that there is no text outside of an insertion, that
# insertions or deletions are not repeated, etc.
# TODO: Make the info command just show info, not extract everything:
# it can be much faster.
# TODO: Perhaps use long integers as sets instead of set objects; may
# be faster.
# TODO: Parallel-extract that passes back each line along with a
# description of which revisions include it. Nice for checking all
# shas in parallel.
class WeaveError(Exception):
"""Exception in processing weave"""
class WeaveFormatError(WeaveError):
"""Weave invariant violated"""
class Weave(object):
"""weave - versioned text file storage.
A Weave manages versions of line-based text files, keeping track
of the originating version for each line.
To clients the "lines" of the file are represented as a list of strings.
These strings will typically have terminal newline characters, but
this is not required. In particular files commonly do not have a newline
at the end of the file.
Texts can be identified in either of two ways:
* a nonnegative index number.
* a version-id string.
Typically the index number will be valid only inside this weave and
the version-id is used to reference it in the larger world.
The weave is represented as a list mixing edit instructions and
literal text. Each entry in _l can be either a string (or
unicode), or a tuple. If a string, it means that the given line
should be output in the currently active revisions.
If a tuple, it gives a processing instruction saying in which
revisions the enclosed lines are active. The tuple has the form
(instruction, version).
The instruction can be '{' or '}' for an insertion block, and '['
and ']' for a deletion block respectively. The version is the
integer version index. There is no replace operator, only deletes
and inserts.
Constraints/notes:
* A later version can delete lines that were introduced by any
number of ancestor versions; this implies that deletion
instructions can span insertion blocks without regard to the
insertion block's nesting.
* Similarly, deletions need not be properly nested with regard to
each other, because they might have been generated by
independent revisions.
* Insertions are always made by inserting a new bracketed block
into a single point in the previous weave. This implies they
can nest but not overlap, and the nesting must always have later
insertions on the inside.
* It doesn't seem very useful to have an active insertion
inside an inactive insertion, but it might happen.
* Therefore, all instructions are always"considered"; that
is passed onto and off the stack. An outer inactive block
doesn't disable an inner block.
* Lines are enabled if the most recent enclosing insertion is
active and none of the enclosing deletions are active.
* There is no point having a deletion directly inside its own
insertion; you might as well just not write it. And there
should be no way to get an earlier version deleting a later
version.
_l
Text of the weave.
_v
List of parents, indexed by version number.
It is only necessary to store the minimal set of parents for
each version; the parent's parents are implied.
_sha1s
List of hex SHA-1 of each version, or None if not recorded.
"""
def __init__(self):
self._l = []
self._v = []
self._sha1s = []
def __eq__(self, other):
if not isinstance(other, Weave):
return False
return self._v == other._v \
and self._l == other._l
def __ne__(self, other):
return not self.__eq__(other)
def add(self, parents, text):
"""Add a single text on top of the weave.
Returns the index number of the newly added version.
parents
List or set of direct parent version numbers.
text
Sequence of lines to be added in the new version."""
## self._check_versions(parents)
## self._check_lines(text)
idx = len(self._v)
import sha
s = sha.new()
for l in text:
s.update(l)
sha1 = s.hexdigest()
del s
# TODO: It'd probably be faster to append things on to a new
# list rather than modifying the existing one, which is likely
# to cause a lot of copying.
if parents:
ancestors = self.inclusions(parents)
delta = self._delta(ancestors, text)
# offset gives the number of lines that have been inserted
# into the weave up to the current point; if the original edit instruction
# says to change line A then we actually change (A+offset)
offset = 0
for i1, i2, newlines in delta:
assert 0 <= i1
assert i1 <= i2
assert i2 <= len(self._l)
# the deletion and insertion are handled separately.
# first delete the region.
if i1 != i2:
self._l.insert(i1+offset, ('[', idx))
self._l.insert(i2+offset+1, (']', idx))
offset += 2
# is this OK???
if newlines:
# there may have been a deletion spanning up to
# i2; we want to insert after this region to make sure
# we don't destroy ourselves
i = i2 + offset
self._l[i:i] = [('{', idx)] \
+ newlines \
+ [('}', idx)]
offset += 2 + len(newlines)
self._addversion(parents)
else:
# special case; adding with no parents revision; can do this
# more quickly by just appending unconditionally
self._l.append(('{', idx))
self._l += text
self._l.append(('}', idx))
self._addversion(None)
self._sha1s.append(sha1)
return idx
def inclusions(self, versions):
"""Return set of all ancestors of given version(s)."""
i = set(versions)
v = max(versions)
try:
while v >= 0:
if v in i:
# include all its parents
i.update(self._v[v])
v -= 1
return i
except IndexError:
raise ValueError("version %d not present in weave" % v)
def minimal_parents(self, version):
"""Find the minimal set of parents for the version."""
included = self._v[version]
if not included:
return []
li = list(included)
li.sort(reverse=True)
mininc = []
gotit = set()
for pv in li:
if pv not in gotit:
mininc.append(pv)
gotit.update(self.inclusions(pv))
assert mininc[0] >= 0
assert mininc[-1] < version
return mininc
def _addversion(self, parents):
if parents:
self._v.append(parents)
else:
self._v.append(set())
def _check_lines(self, text):
if not isinstance(text, list):
raise ValueError("text should be a list, not %s" % type(text))
for l in text:
if not isinstance(l, basestring):
raise ValueError("text line should be a string or unicode, not %s"
% type(l))
def _check_versions(self, indexes):
"""Check everything in the sequence of indexes is valid"""
for i in indexes:
try:
self._v[i]
except IndexError:
raise IndexError("invalid version number %r" % i)
def annotate(self, index):
return list(self.annotate_iter(index))
def annotate_iter(self, version):
"""Yield list of (index-id, line) pairs for the specified version.
The index indicates when the line originated in the weave."""
for origin, lineno, text in self._extract([version]):
yield origin, text
def _walk(self):
"""Walk the weave.
Yields sequence of
(lineno, insert, deletes, text)
for each literal line.
"""
istack = []
dset = set()
lineno = 0 # line of weave, 0-based
for l in self._l:
if isinstance(l, tuple):
c, v = l
isactive = None
if c == '{':
istack.append(v)
elif c == '}':
oldv = istack.pop()
elif c == '[':
assert v not in dset
dset.add(v)
elif c == ']':
dset.remove(v)
else:
raise WeaveFormatError('unexpected instruction %r'
% v)
else:
assert isinstance(l, basestring)
assert istack
yield lineno, istack[-1], dset, l
lineno += 1
def _extract(self, versions):
"""Yield annotation of lines in included set.
Yields a sequence of tuples (origin, lineno, text), where
origin is the origin version, lineno the index in the weave,
and text the text of the line.
The set typically but not necessarily corresponds to a version.
"""
included = self.inclusions(versions)
istack = []
dset = set()
lineno = 0 # line of weave, 0-based
isactive = None
result = []
WFE = WeaveFormatError
for l in self._l:
if isinstance(l, tuple):
c, v = l
isactive = None
if c == '{':
assert v not in istack
istack.append(v)
elif c == '}':
oldv = istack.pop()
assert oldv == v
elif c == '[':
if v in included:
assert v not in dset
dset.add(v)
else:
assert c == ']'
if v in included:
assert v in dset
dset.remove(v)
else:
assert isinstance(l, basestring)
if isactive is None:
isactive = (not dset) and istack and (istack[-1] in included)
if isactive:
result.append((istack[-1], lineno, l))
lineno += 1
if istack:
raise WFE("unclosed insertion blocks at end of weave",
istack)
if dset:
raise WFE("unclosed deletion blocks at end of weave",
dset)
return result
def get_iter(self, version):
"""Yield lines for the specified version."""
for origin, lineno, line in self._extract([version]):
yield line
def get(self, index):
return list(self.get_iter(index))
def mash_iter(self, included):
"""Return composed version of multiple included versions."""
for origin, lineno, text in self._extract(included):
yield text
def dump(self, to_file):
from pprint import pprint
print >>to_file, "Weave._l = ",
pprint(self._l, to_file)
print >>to_file, "Weave._v = ",
pprint(self._v, to_file)
def numversions(self):
l = len(self._v)
assert l == len(self._sha1s)
return l
def check(self, progress_bar=None):
# check no circular inclusions
for version in range(self.numversions()):
inclusions = list(self._v[version])
if inclusions:
inclusions.sort()
if inclusions[-1] >= version:
raise WeaveFormatError("invalid included version %d for index %d"
% (inclusions[-1], version))
# try extracting all versions; this is a bit slow and parallel
# extraction could be used
import sha
nv = self.numversions()
for version in range(nv):
if progress_bar:
progress_bar.update('checking text', version, nv)
s = sha.new()
for l in self.get_iter(version):
s.update(l)
hd = s.hexdigest()
expected = self._sha1s[version]
if hd != expected:
raise WeaveError("mismatched sha1 for version %d; "
"got %s, expected %s"
% (version, hd, expected))
# TODO: check insertions are properly nested, that there are
# no lines outside of insertion blocks, that deletions are
# properly paired, etc.
def merge(self, merge_versions):
"""Automerge and mark conflicts between versions.
This returns a sequence, each entry describing alternatives
for a chunk of the file. Each of the alternatives is given as
a list of lines.
If there is a chunk of the file where there's no diagreement,
only one alternative is given.
"""
# approach: find the included versions common to all the
# merged versions
raise NotImplementedError()
def _delta(self, included, lines):
"""Return changes from basis to new revision.
The old text for comparison is the union of included revisions.
This is used in inserting a new text.
Delta is returned as a sequence of
(weave1, weave2, newlines).
This indicates that weave1:weave2 of the old weave should be
replaced by the sequence of lines in newlines. Note that
these line numbers are positions in the total weave and don't
correspond to the lines in any extracted version, or even the
extracted union of included versions.
If line1=line2, this is a pure insert; if newlines=[] this is a
pure delete. (Similar to difflib.)
"""
# basis a list of (origin, lineno, line)
basis_lineno = []
basis_lines = []
for origin, lineno, line in self._extract(included):
basis_lineno.append(lineno)
basis_lines.append(line)
# add a sentinal, because we can also match against the final line
basis_lineno.append(len(self._l))
# XXX: which line of the weave should we really consider
# matches the end of the file? the current code says it's the
# last line of the weave?
from difflib import SequenceMatcher
s = SequenceMatcher(None, basis_lines, lines)
# TODO: Perhaps return line numbers from composed weave as well?
for tag, i1, i2, j1, j2 in s.get_opcodes():
##print tag, i1, i2, j1, j2
if tag == 'equal':
continue
# i1,i2 are given in offsets within basis_lines; we need to map them
# back to offsets within the entire weave
real_i1 = basis_lineno[i1]
real_i2 = basis_lineno[i2]
assert 0 <= j1
assert j1 <= j2
assert j2 <= len(lines)
yield real_i1, real_i2, lines[j1:j2]
def plan_merge(self, ver_a, ver_b):
"""Return pseudo-annotation indicating how the two versions merge.
This is computed between versions a and b and their common
base.
Weave lines present in none of them are skipped entirely.
"""
inc_a = self.inclusions([ver_a])
inc_b = self.inclusions([ver_b])
inc_c = inc_a & inc_b
for lineno, insert, deleteset, line in self._walk():
if deleteset & inc_c:
# killed in parent; can't be in either a or b
# not relevant to our work
yield 'killed-base', line
elif insert in inc_c:
# was inserted in base
killed_a = bool(deleteset & inc_a)
killed_b = bool(deleteset & inc_b)
if killed_a and killed_b:
yield 'killed-both', line
elif killed_a:
yield 'killed-a', line
elif killed_b:
yield 'killed-b', line
else:
yield 'unchanged', line
elif insert in inc_a:
if deleteset & inc_a:
yield 'ghost-a', line
else:
# new in A; not in B
yield 'new-a', line
elif insert in inc_b:
if deleteset & inc_b:
yield 'ghost-b', line
else:
yield 'new-b', line
else:
# not in either revision
yield 'irrelevant', line
yield 'unchanged', '' # terminator
def weave_merge(self, plan):
lines_a = []
lines_b = []
ch_a = ch_b = False
for state, line in plan:
if state == 'unchanged' or state == 'killed-both':
# resync and flush queued conflicts changes if any
if not lines_a and not lines_b:
pass
elif ch_a and not ch_b:
# one-sided change:
for l in lines_a: yield l
elif ch_b and not ch_a:
for l in lines_b: yield l
elif lines_a == lines_b:
for l in lines_a: yield l
else:
yield '<<<<\n'
for l in lines_a: yield l
yield '====\n'
for l in lines_b: yield l
yield '>>>>\n'
del lines_a[:]
del lines_b[:]
ch_a = ch_b = False
if state == 'unchanged':
if line:
yield line
elif state == 'killed-a':
ch_a = True
lines_b.append(line)
elif state == 'killed-b':
ch_b = True
lines_a.append(line)
elif state == 'new-a':
ch_a = True
lines_a.append(line)
elif state == 'new-b':
ch_b = True
lines_b.append(line)
else:
assert state in ('irrelevant', 'ghost-a', 'ghost-b', 'killed-base',
'killed-both'), \
state
def weave_info(filename, out):
"""Show some text information about the weave."""
from weavefile import read_weave
wf = file(filename, 'rb')
w = read_weave(wf)
# FIXME: doesn't work on pipes
weave_size = wf.tell()
print >>out, "weave file size %d bytes" % weave_size
print >>out, "weave contains %d versions" % len(w._v)
total = 0
print '%6s %6s %8s %40s %20s' % ('ver', 'lines', 'bytes', 'sha1', 'parents')
for i in (6, 6, 8, 40, 20):
print '-' * i,
print
for i in range(len(w._v)):
text = w.get(i)
lines = len(text)
bytes = sum((len(a) for a in text))
sha1 = w._sha1s[i]
print '%6d %6d %8d %40s' % (i, lines, bytes, sha1),
for pv in w._v[i]:
print pv,
print
total += bytes
print >>out, "versions total %d bytes" % total
print >>out, "compression ratio %.3f" % (float(total)/float(weave_size))
def usage():
print """bzr weave tool
Experimental tool for weave algorithm.
usage:
weave init WEAVEFILE
Create an empty weave file
weave get WEAVEFILE VERSION
Write out specified version.
weave check WEAVEFILE
Check consistency of all versions.
weave info WEAVEFILE
Display table of contents.
weave add WEAVEFILE [BASE...] < NEWTEXT
Add NEWTEXT, with specified parent versions.
weave annotate WEAVEFILE VERSION
Display origin of each line.
weave mash WEAVEFILE VERSION...
Display composite of all selected versions.
weave merge WEAVEFILE VERSION1 VERSION2 > OUT
Auto-merge two versions and display conflicts.
example:
% weave init foo.weave
% vi foo.txt
% weave add foo.weave < foo.txt
added version 0
(create updated version)
% vi foo.txt
% weave get foo.weave 0 | diff -u - foo.txt
% weave add foo.weave 0 < foo.txt
added version 1
% weave get foo.weave 0 > foo.txt (create forked version)
% vi foo.txt
% weave add foo.weave 0 < foo.txt
added version 2
% weave merge foo.weave 1 2 > foo.txt (merge them)
% vi foo.txt (resolve conflicts)
% weave add foo.weave 1 2 < foo.txt (commit merged version)
"""
def main(argv):
import sys
import os
from weavefile import write_weave, read_weave
from bzrlib.progress import ProgressBar
#import psyco
#psyco.full()
cmd = argv[1]
def readit():
return read_weave(file(argv[2], 'rb'))
if cmd == 'help':
usage()
elif cmd == 'add':
w = readit()
# at the moment, based on everything in the file
parents = map(int, argv[3:])
lines = sys.stdin.readlines()
ver = w.add(parents, lines)
write_weave(w, file(argv[2], 'wb'))
print 'added version %d' % ver
elif cmd == 'init':
fn = argv[2]
if os.path.exists(fn):
raise IOError("file exists")
w = Weave()
write_weave(w, file(fn, 'wb'))
elif cmd == 'get': # get one version
w = readit()
sys.stdout.writelines(w.get_iter(int(argv[3])))
elif cmd == 'mash': # get composite
w = readit()
sys.stdout.writelines(w.mash_iter(map(int, argv[3:])))
elif cmd == 'annotate':
w = readit()
# newline is added to all lines regardless; too hard to get
# reasonable formatting otherwise
lasto = None
for origin, text in w.annotate(int(argv[3])):
text = text.rstrip('\r\n')
if origin == lasto:
print ' | %s' % (text)
else:
print '%5d | %s' % (origin, text)
lasto = origin
elif cmd == 'info':
weave_info(argv[2], sys.stdout)
elif cmd == 'check':
w = readit()
pb = ProgressBar()
w.check(pb)
pb.clear()
elif cmd == 'inclusions':
w = readit()
print ' '.join(map(str, w.inclusions([int(argv[3])])))
elif cmd == 'parents':
w = readit()
print ' '.join(map(str, w._v[int(argv[3])]))
elif cmd == 'plan-merge':
w = readit()
for state, line in w.plan_merge(int(argv[3]), int(argv[4])):
if line:
print '%14s | %s' % (state, line),
elif cmd == 'merge':
w = readit()
p = w.plan_merge(int(argv[3]), int(argv[4]))
sys.stdout.writelines(w.weave_merge(p))
elif cmd == 'mash-merge':
if len(argv) != 5:
usage()
return 1
w = readit()
v1, v2 = map(int, argv[3:5])
basis = w.inclusions([v1]).intersection(w.inclusions([v2]))
base_lines = list(w.mash_iter(basis))
a_lines = list(w.get(v1))
b_lines = list(w.get(v2))
from bzrlib.merge3 import Merge3
m3 = Merge3(base_lines, a_lines, b_lines)
name_a = 'version %d' % v1
name_b = 'version %d' % v2
sys.stdout.writelines(m3.merge_lines(name_a=name_a, name_b=name_b))
else:
raise ValueError('unknown command %r' % cmd)
if __name__ == '__main__':
import sys
sys.exit(main(sys.argv))
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