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More work on appy.shared.diff...

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This commit is contained in:
Gaetan Delannay 2011-11-18 01:01:50 +01:00
parent 2ec05939fe
commit cf992843ff
1 changed files with 63 additions and 29 deletions
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64
shared/diff.py
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@ -87,6 +87,16 @@ class Merger:
# Get the overlapping (new) diff.
newDiff, newDiffStart, isPrevious = self.getNextDiff()
if not newDiff:
# No more new diff. So normally, we should find what remains in
# oldText at self.lineB[self.i:]
if not self.lineB[self.i:].startswith(oldText):
# Anormal additional char. Probably a space? Indeed,
# word-level comparisons imply split(' ') which can be
# error-prone.
res += self.lineB[self.i]
self.i += 1
if not self.lineB[self.i:].startswith(oldText):
raise 'Error!!!!'
res += self.differ.getModifiedChunk(oldText, 'insert', '',
msg=oldDiff.group(2))
self.i += len(oldText)
@ -118,6 +128,9 @@ class Merger:
def merge(self):
'''Merges self.previousDiffs into self.lineB.'''
res = ''
print 'MERGE'
print 'Line A', self.lineA
print 'Line B', self.lineB
diff, diffStart, isPrevious = self.getNextDiff()
while diff:
# Dump the part of lineB between self.i and diffStart
@ -136,6 +149,8 @@ class Merger:
overlap = self.manageOverlap(diff)
res += overlap
elif diff.group(1) == 'delete':
res += diff.group(0)
else:
# Dump the diff and update self.i
res += diff.group(0)
@ -208,7 +223,7 @@ class HtmlDiff:
# Will the surrouding tag be a div or a span?
if sep == '\n': tag = 'div'
else: tag = 'span'
# What message wiill it show in its 'title' attribute?
# What message will it show in its 'title' attribute?
if not msg:
exec 'msg = self.%sMsg' % type
# What CSS class (or, if none, tag-specific style) will be used ?
@ -221,9 +236,10 @@ class HtmlDiff:
# the 'name' attribute of the tag indicates the type of the update.
exec 'tagName = self.%sName' % type
# The idea is: if there are several lines, every line must be surrounded
# by a tag. this way, we know that a surrounding tag can't span several
# by a tag. This way, we know that a surrounding tag can't span several
# lines, which is a prerequisite for managing cumulative diffs.
if sep == ' ':
if not isinstance(seq, basestring):
seq = sep.join(seq)
sep = ''
if isinstance(seq, basestring):
@ -307,7 +323,7 @@ class HtmlDiff:
# Wrap content info reified tag
return startTag + content + endTag
def getSeqDiff(self, seqA, seqB):
def getSeqDiff(self, seqA, seqB, sep):
'''p_seqA and p_seqB are lists of strings. Here we will try to identify
similarities between strings from p_seqA and p_seqB, and return a
list of differences between p_seqA and p_seqB, where each element
@ -369,7 +385,17 @@ class HtmlDiff:
# Consider any "unconsumed" line from p_seqB as being inserted.
if k < len(seqB):
for line in seqB[k:]: res.append( ('insert', line) )
return res
# Merge similar diffs, excepted if separator is a carriage return
if sep == '\n': return res
newRes = []
lastType = None
for type, data in res:
if lastType and (type != 'replace') and (lastType == type):
newRes[-1] = (type, newRes[-1][1] + sep + data)
else:
newRes.append( (type, data) )
lastType = type
return newRes
def split(self, s, sep):
'''Splits string p_s with p_sep. If p_sep is a space, the split can't
@ -395,7 +421,8 @@ class HtmlDiff:
i -= 1
return l
def getLineReplacement(self, lineA, lineB, previousDiffsA, outerTagA):
nextSeps = {'\n': ' ', ' ': ''}
def getReplacement(self, sep, lineA, lineB, previousDiffsA, outerTagA):
'''p_lineA has been replaced with p_lineB. Here, we will investigate
further here and explore differences at the *word* level between
p_lineA and p_lineB.
@ -414,8 +441,8 @@ class HtmlDiff:
contentA = matchA and matchA.group(3) or lineA
matchB = htmlTag.match(lineB)
contentB = matchB and matchB.group(3) or lineB
# Perform the diff at the level fo words
diff = self.getHtmlDiff(contentA, contentB, ' ')
# Perform the diff at the level of words
diff = self.getHtmlDiff(contentA, contentB, self.nextSeps[sep])
if matchB:
res = self.computeTag(matchB, diff)
else:
@ -441,8 +468,12 @@ class HtmlDiff:
similar in a previous call to m_getHtmlDiff with sep=carriage
return.'''
res = []
if sep:
a = self.split(old, sep)
b = self.split(new, sep)
else:
a = old
b = new
matcher = difflib.SequenceMatcher()
matcher.set_seqs(a, b)
for action, i1, i2, j1, j2 in matcher.get_opcodes():
@ -467,24 +498,27 @@ class HtmlDiff:
# Was a deletion, not a replacement
toAdd = self.getModifiedChunk(chunkA, 'delete', sep)
else: # At least, a true replacement
if sep == '\n':
toAdd = []
# We know that some lines have been replaced from a to
# b. By identifying similarities between those lines,
# We know that some lines/words have been replaced from a to
# b. By identifying similarities between those lines/words,
# consider some as having been deleted, modified or
# inserted.
for sAction, line in self.getSeqDiff(chunkA, chunkB):
for sAction, line in self.getSeqDiff(chunkA, chunkB, sep):
if sAction in ('insert', 'delete'):
mChunk = self.getModifiedChunk(line, sAction, sep)
toAdd.append(mChunk)
elif sAction == 'equal':
toAdd.append(line)
elif sAction == 'replace':
toAdd.append(self.getLineReplacement(*line))
toAdd.append(self.getReplacement(sep, *line))
# The following line, when sep is the space (=when workin
# on diffs at the word level), leads to additional spaces
# being dumped into the result (ie, a space between a delete
# and an insert, which was not in the initial text). We
# could not find a way to avoid inserting those spaces. So
# when merging diffs (see Merger.merge), we know that a
# 'space' error can occur and we take it into account then.
toAdd = sep.join(toAdd)
else:
toAdd = self.getModifiedChunk(chunkA, 'delete', sep)
toAdd += self.getModifiedChunk(chunkB, 'insert', sep)
if toAdd: res.append(toAdd)
return sep.join(res)