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"""Weave - storage of related text file versions"""
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# before intset (r923) 2000 versions in 41.5s
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# with intset (r926) 2000 versions in 93s !!!
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# better to just use plain sets.
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# making _extract build and return a list, rather than being a generator
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# with python -O, r923 does 2000 versions in 36.87s
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# with optimizations to avoid mutating lists - 35.75! I guess copying
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# all the elements every time costs more than the small manipulations.
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# a surprisingly small change.
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# r931, which avoids using a generator for extract, does 36.98s
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# with memoized inclusions, takes 41.49s; not very good
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# with slots, takes 37.35s; without takes 39.16, a bit surprising
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# with the delta calculation mixed in with the add method, rather than
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# separated, takes 36.78s
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# with delta folded in and mutation of the list, 36.13s
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# with all this and simplification of add code, 33s
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# TODO: Perhaps have copy method for Weave instances?
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# XXX: If we do weaves this way, will a merge still behave the same
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# way if it's done in a different order? That's a pretty desirable
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# TODO: How to write these to disk? One option is cPickle, which
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# would be fast but less friendly to C, and perhaps not portable. Another is
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# TODO: Nothing here so far assumes the lines are really \n newlines,
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# rather than being split up in some other way. We could accomodate
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# binaries, perhaps by naively splitting on \n or perhaps using
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# something like a rolling checksum.
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# TODO: Perhaps track SHA-1 in the header for protection? This would
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# be redundant with it being stored in the inventory, but perhaps
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# TODO: Track version names as well as indexes.
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# TODO: Probably do transitive expansion when specifying parents?
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# TODO: Separate out some code to read and write weaves.
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# TODO: End marker for each version so we can stop reading?
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# TODO: Check that no insertion occurs inside a deletion that was
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# active in the version of the insertion.
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# TODO: In addition to the SHA-1 check, perhaps have some code that
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# checks structural constraints of the weave: ie that insertions are
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# properly nested, that there is no text outside of an insertion, that
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# insertions or deletions are not repeated, etc.
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# TODO: Parallel-extract that passes back each line along with a
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# description of which revisions include it. Nice for checking all
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# TODO: Perhaps a special slower check() method that verifies more
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# nesting constraints and the MD5 of each version?
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from sets import Set, ImmutableSet
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frozenset = ImmutableSet
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class WeaveError(Exception):
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Sequence of lines to be added in the new version."""
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self._check_versions(parents)
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## self._check_versions(parents)
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## self._check_lines(text)
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new_version = len(self._parents)
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sha1 = s.hexdigest()
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# if we abort after here the weave will be corrupt
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self._parents.append(frozenset(parents))
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ancestors = self.inclusions(parents)
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delta = self._delta(ancestors, text)
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# offset gives the number of lines that have been inserted
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# into the weave up to the current point; if the original edit instruction
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# says to change line A then we actually change (A+offset)
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for i1, i2, newlines in delta:
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assert i2 <= len(self._l)
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# the deletion and insertion are handled separately.
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# first delete the region.
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self._l.insert(i1+offset, ('[', idx))
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self._l.insert(i2+offset+1, (']', idx))
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# there may have been a deletion spanning up to
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# i2; we want to insert after this region to make sure
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# we don't destroy ourselves
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self._l[i:i] = [('{', idx)] \
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offset += 2 + len(newlines)
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self._addversion(parents)
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# special case; adding with no parents revision; can do this
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# more quickly by just appending unconditionally
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self._l.append(('{', idx))
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self._l.append(('}', idx))
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self._addversion(None)
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self._sha1s.append(sha1)
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# special case; adding with no parents revision; can do
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# this more quickly by just appending unconditionally.
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# even more specially, if we're adding an empty text we
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# need do nothing at all.
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self._weave.append(('{', new_version))
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self._weave.extend(text)
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self._weave.append(('}', new_version))
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if len(parents) == 1:
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pv = list(parents)[0]
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if sha1 == self._sha1s[pv]:
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# special case: same as the single parent
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ancestors = self.inclusions(parents)
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# basis a list of (origin, lineno, line)
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for origin, lineno, line in self._extract(ancestors):
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basis_lineno.append(lineno)
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basis_lines.append(line)
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# another small special case: a merge, producing the same text as auto-merge
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if text == basis_lines:
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# add a sentinal, because we can also match against the final line
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basis_lineno.append(len(self._weave))
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# XXX: which line of the weave should we really consider
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# matches the end of the file? the current code says it's the
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# last line of the weave?
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#print 'basis_lines:', basis_lines
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#print 'new_lines: ', lines
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from difflib import SequenceMatcher
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s = SequenceMatcher(None, basis_lines, text)
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# offset gives the number of lines that have been inserted
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# into the weave up to the current point; if the original edit instruction
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# says to change line A then we actually change (A+offset)
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for tag, i1, i2, j1, j2 in s.get_opcodes():
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# i1,i2 are given in offsets within basis_lines; we need to map them
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# back to offsets within the entire weave
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#print 'raw match', tag, i1, i2, j1, j2
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i1 = basis_lineno[i1]
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i2 = basis_lineno[i2]
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assert 0 <= j1 <= j2 <= len(text)
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#print tag, i1, i2, j1, j2
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# the deletion and insertion are handled separately.
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# first delete the region.
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self._weave.insert(i1+offset, ('[', new_version))
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self._weave.insert(i2+offset+1, (']', new_version))
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# there may have been a deletion spanning up to
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# i2; we want to insert after this region to make sure
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# we don't destroy ourselves
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self._weave[i:i] = ([('{', new_version)]
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+ [('}', new_version)])
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offset += 2 + (j2 - j1)
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def inclusions(self, versions):
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def mash_iter(self, included):
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"""Return composed version of multiple included versions."""
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included = frozenset(included)
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for origin, lineno, text in self._extract(included):
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def dump(self, to_file):
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from pprint import pprint
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print >>to_file, "Weave._weave = ",
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pprint(self._weave, to_file)
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print >>to_file, "Weave._parents = ",
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pprint(self._parents, to_file)
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print >>to_file, "Weave._l = ",
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pprint(self._l, to_file)
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print >>to_file, "Weave._v = ",
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pprint(self._v, to_file)
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def numversions(self):
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l = len(self._parents)
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assert l == len(self._sha1s)
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return self.numversions()
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def check(self, progress_bar=None):
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# check no circular inclusions
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for version in range(self.numversions()):
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inclusions = list(self._parents[version])
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inclusions = list(self._v[version])
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inclusions.sort()
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if inclusions[-1] >= version:
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If line1=line2, this is a pure insert; if newlines=[] this is a
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pure delete. (Similar to difflib.)
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def plan_merge(self, ver_a, ver_b):
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"""Return pseudo-annotation indicating how the two versions merge.
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This is computed between versions a and b and their common
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Weave lines present in none of them are skipped entirely.
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inc_a = self.inclusions([ver_a])
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inc_b = self.inclusions([ver_b])
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inc_c = inc_a & inc_b
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for lineno, insert, deleteset, line in self._walk():
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if deleteset & inc_c:
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# killed in parent; can't be in either a or b
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# not relevant to our work
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yield 'killed-base', line
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elif insert in inc_c:
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# was inserted in base
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killed_a = bool(deleteset & inc_a)
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killed_b = bool(deleteset & inc_b)
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if killed_a and killed_b:
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yield 'killed-both', line
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yield 'killed-a', line
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yield 'killed-b', line
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yield 'unchanged', line
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elif insert in inc_a:
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if deleteset & inc_a:
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yield 'ghost-a', line
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elif insert in inc_b:
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if deleteset & inc_b:
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yield 'ghost-b', line
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# not in either revision
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yield 'irrelevant', line
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yield 'unchanged', '' # terminator
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def weave_merge(self, plan):
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for state, line in plan:
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if state == 'unchanged' or state == 'killed-both':
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# resync and flush queued conflicts changes if any
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if not lines_a and not lines_b:
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elif ch_a and not ch_b:
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for l in lines_a: yield l
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elif ch_b and not ch_a:
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for l in lines_b: yield l
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elif lines_a == lines_b:
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for l in lines_a: yield l
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for l in lines_a: yield l
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for l in lines_b: yield l
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if state == 'unchanged':
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elif state == 'killed-a':
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elif state == 'killed-b':
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elif state == 'new-a':
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elif state == 'new-b':
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assert state in ('irrelevant', 'ghost-a', 'ghost-b', 'killed-base',
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# basis a list of (origin, lineno, line)
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for origin, lineno, line in self._extract(included):
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basis_lineno.append(lineno)
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basis_lines.append(line)
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# add a sentinal, because we can also match against the final line
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basis_lineno.append(len(self._l))
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# XXX: which line of the weave should we really consider
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# matches the end of the file? the current code says it's the
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# last line of the weave?
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from difflib import SequenceMatcher
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s = SequenceMatcher(None, basis_lines, lines)
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# TODO: Perhaps return line numbers from composed weave as well?
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for tag, i1, i2, j1, j2 in s.get_opcodes():
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##print tag, i1, i2, j1, j2
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# i1,i2 are given in offsets within basis_lines; we need to map them
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# back to offsets within the entire weave
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real_i1 = basis_lineno[i1]
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real_i2 = basis_lineno[i2]
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assert j2 <= len(lines)
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yield real_i1, real_i2, lines[j1:j2]
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def weave_info(filename, out):
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"""Show some text information about the weave."""
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print '%6s %40s %20s' % ('ver', 'sha1', 'parents')
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for i in (6, 40, 20):
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for i in range(w.numversions()):
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print '%6d %40s %s' % (i, sha1, ' '.join(map(str, w._parents[i])))
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def weave_stats(weave_file):
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from bzrlib.progress import ProgressBar
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from bzrlib.weavefile import read_weave
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wf = file(weave_file, 'rb')
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from weavefile import read_weave
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wf = file(filename, 'rb')
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w = read_weave(wf)
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# FIXME: doesn't work on pipes
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weave_size = wf.tell()
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print >>out, "weave file size %d bytes" % weave_size
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print >>out, "weave contains %d versions" % len(w._v)
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for i in range(vers):
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pb.update('checking sizes', i, vers)
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for line in w.get_iter(i):
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print 'versions %9d' % vers
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print 'weave file %9d bytes' % weave_size
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print 'total contents %9d bytes' % total
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print 'compression ratio %9.2fx' % (float(total) / float(weave_size))
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print '%6s %6s %8s %40s %20s' % ('ver', 'lines', 'bytes', 'sha1', 'parents')
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for i in (6, 6, 8, 40, 20):
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for i in range(len(w._v)):
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bytes = sum((len(a) for a in text))
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print '%6d %6d %8d %40s' % (i, lines, bytes, sha1),
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print >>out, "versions total %d bytes" % total
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print >>out, "compression ratio %.3f" % (float(total)/float(weave_size))