Mercurial > hg
view mercurial/mdiff.py @ 26755:bb0b955d050d
streamclone: support for producing and consuming stream clone bundles
Up to this point, stream clones only existed as a dynamically generated
data format produced and consumed during streaming clones. In order to
support this efficient cloning format with the clone bundles feature, we
need a more formal, on disk representation of the streaming clone data.
This patch introduces a new "bundle" type for streaming clones. Unlike
existing bundles, it does not contain changegroup data. It does,
however, share the same concepts like the 4 byte header which identifies
the type of data that follows and the 2 byte abbreviation for
compression types (of which only "UN" is currently supported).
The new bundle format is essentially the existing stream clone version 1
data format with some headers at the beginning.
Content negotiation at stream clone request time checked for repository
format/requirements compatibility before initiating a stream clone. We
can't do active content negotiation when using clone bundles. So, we put
this set of requirements inside the payload so consumers have a built-in
mechanism for checking compatibility before reading and applying lots of
data. Of course, we will also advertise this requirements set in clone
bundles. But that's for another patch.
We currently don't have a mechanism to produce and consume this new
bundle format. This will be implemented in upcoming patches.
It's worth noting that if a legacy client attempts to `hg unbundle` a
stream clone bundle (with the "HGS1" header), it will abort with:
"unknown bundle version S1," which seems appropriate.
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Sat, 17 Oct 2015 11:14:52 -0700 |
parents | 56b2bcea2529 |
children | 0d7635dca691 |
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# mdiff.py - diff and patch routines for mercurial # # Copyright 2005, 2006 Matt Mackall <mpm@selenic.com> # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. from i18n import _ import bdiff, mpatch, util, base85, error import re, struct, zlib def splitnewlines(text): '''like str.splitlines, but only split on newlines.''' lines = [l + '\n' for l in text.split('\n')] if lines: if lines[-1] == '\n': lines.pop() else: lines[-1] = lines[-1][:-1] return lines class diffopts(object): '''context is the number of context lines text treats all files as text showfunc enables diff -p output git enables the git extended patch format nodates removes dates from diff headers nobinary ignores binary files noprefix disables the 'a/' and 'b/' prefixes (ignored in plain mode) ignorews ignores all whitespace changes in the diff ignorewsamount ignores changes in the amount of whitespace ignoreblanklines ignores changes whose lines are all blank upgrade generates git diffs to avoid data loss ''' defaults = { 'context': 3, 'text': False, 'showfunc': False, 'git': False, 'nodates': False, 'nobinary': False, 'noprefix': False, 'ignorews': False, 'ignorewsamount': False, 'ignoreblanklines': False, 'upgrade': False, } __slots__ = defaults.keys() def __init__(self, **opts): for k in self.__slots__: v = opts.get(k) if v is None: v = self.defaults[k] setattr(self, k, v) try: self.context = int(self.context) except ValueError: raise error.Abort(_('diff context lines count must be ' 'an integer, not %r') % self.context) def copy(self, **kwargs): opts = dict((k, getattr(self, k)) for k in self.defaults) opts.update(kwargs) return diffopts(**opts) defaultopts = diffopts() def wsclean(opts, text, blank=True): if opts.ignorews: text = bdiff.fixws(text, 1) elif opts.ignorewsamount: text = bdiff.fixws(text, 0) if blank and opts.ignoreblanklines: text = re.sub('\n+', '\n', text).strip('\n') return text def splitblock(base1, lines1, base2, lines2, opts): # The input lines matches except for interwoven blank lines. We # transform it into a sequence of matching blocks and blank blocks. lines1 = [(wsclean(opts, l) and 1 or 0) for l in lines1] lines2 = [(wsclean(opts, l) and 1 or 0) for l in lines2] s1, e1 = 0, len(lines1) s2, e2 = 0, len(lines2) while s1 < e1 or s2 < e2: i1, i2, btype = s1, s2, '=' if (i1 >= e1 or lines1[i1] == 0 or i2 >= e2 or lines2[i2] == 0): # Consume the block of blank lines btype = '~' while i1 < e1 and lines1[i1] == 0: i1 += 1 while i2 < e2 and lines2[i2] == 0: i2 += 1 else: # Consume the matching lines while i1 < e1 and lines1[i1] == 1 and lines2[i2] == 1: i1 += 1 i2 += 1 yield [base1 + s1, base1 + i1, base2 + s2, base2 + i2], btype s1 = i1 s2 = i2 def allblocks(text1, text2, opts=None, lines1=None, lines2=None, refine=False): """Return (block, type) tuples, where block is an mdiff.blocks line entry. type is '=' for blocks matching exactly one another (bdiff blocks), '!' for non-matching blocks and '~' for blocks matching only after having filtered blank lines. If refine is True, then '~' blocks are refined and are only made of blank lines. line1 and line2 are text1 and text2 split with splitnewlines() if they are already available. """ if opts is None: opts = defaultopts if opts.ignorews or opts.ignorewsamount: text1 = wsclean(opts, text1, False) text2 = wsclean(opts, text2, False) diff = bdiff.blocks(text1, text2) for i, s1 in enumerate(diff): # The first match is special. # we've either found a match starting at line 0 or a match later # in the file. If it starts later, old and new below will both be # empty and we'll continue to the next match. if i > 0: s = diff[i - 1] else: s = [0, 0, 0, 0] s = [s[1], s1[0], s[3], s1[2]] # bdiff sometimes gives huge matches past eof, this check eats them, # and deals with the special first match case described above if s[0] != s[1] or s[2] != s[3]: type = '!' if opts.ignoreblanklines: if lines1 is None: lines1 = splitnewlines(text1) if lines2 is None: lines2 = splitnewlines(text2) old = wsclean(opts, "".join(lines1[s[0]:s[1]])) new = wsclean(opts, "".join(lines2[s[2]:s[3]])) if old == new: type = '~' yield s, type yield s1, '=' def unidiff(a, ad, b, bd, fn1, fn2, opts=defaultopts): def datetag(date, fn=None): if not opts.git and not opts.nodates: return '\t%s\n' % date if fn and ' ' in fn: return '\t\n' return '\n' if not a and not b: return "" if opts.noprefix: aprefix = bprefix = '' else: aprefix = 'a/' bprefix = 'b/' epoch = util.datestr((0, 0)) fn1 = util.pconvert(fn1) fn2 = util.pconvert(fn2) if not opts.text and (util.binary(a) or util.binary(b)): if a and b and len(a) == len(b) and a == b: return "" l = ['Binary file %s has changed\n' % fn1] elif not a: b = splitnewlines(b) if a is None: l1 = '--- /dev/null%s' % datetag(epoch) else: l1 = "--- %s%s%s" % (aprefix, fn1, datetag(ad, fn1)) l2 = "+++ %s%s" % (bprefix + fn2, datetag(bd, fn2)) l3 = "@@ -0,0 +1,%d @@\n" % len(b) l = [l1, l2, l3] + ["+" + e for e in b] elif not b: a = splitnewlines(a) l1 = "--- %s%s%s" % (aprefix, fn1, datetag(ad, fn1)) if b is None: l2 = '+++ /dev/null%s' % datetag(epoch) else: l2 = "+++ %s%s%s" % (bprefix, fn2, datetag(bd, fn2)) l3 = "@@ -1,%d +0,0 @@\n" % len(a) l = [l1, l2, l3] + ["-" + e for e in a] else: al = splitnewlines(a) bl = splitnewlines(b) l = list(_unidiff(a, b, al, bl, opts=opts)) if not l: return "" l.insert(0, "--- %s%s%s" % (aprefix, fn1, datetag(ad, fn1))) l.insert(1, "+++ %s%s%s" % (bprefix, fn2, datetag(bd, fn2))) for ln in xrange(len(l)): if l[ln][-1] != '\n': l[ln] += "\n\ No newline at end of file\n" return "".join(l) # creates a headerless unified diff # t1 and t2 are the text to be diffed # l1 and l2 are the text broken up into lines def _unidiff(t1, t2, l1, l2, opts=defaultopts): def contextend(l, len): ret = l + opts.context if ret > len: ret = len return ret def contextstart(l): ret = l - opts.context if ret < 0: return 0 return ret lastfunc = [0, ''] def yieldhunk(hunk): (astart, a2, bstart, b2, delta) = hunk aend = contextend(a2, len(l1)) alen = aend - astart blen = b2 - bstart + aend - a2 func = "" if opts.showfunc: lastpos, func = lastfunc # walk backwards from the start of the context up to the start of # the previous hunk context until we find a line starting with an # alphanumeric char. for i in xrange(astart - 1, lastpos - 1, -1): if l1[i][0].isalnum(): func = ' ' + l1[i].rstrip()[:40] lastfunc[1] = func break # by recording this hunk's starting point as the next place to # start looking for function lines, we avoid reading any line in # the file more than once. lastfunc[0] = astart # zero-length hunk ranges report their start line as one less if alen: astart += 1 if blen: bstart += 1 yield "@@ -%d,%d +%d,%d @@%s\n" % (astart, alen, bstart, blen, func) for x in delta: yield x for x in xrange(a2, aend): yield ' ' + l1[x] # bdiff.blocks gives us the matching sequences in the files. The loop # below finds the spaces between those matching sequences and translates # them into diff output. # hunk = None ignoredlines = 0 for s, stype in allblocks(t1, t2, opts, l1, l2): a1, a2, b1, b2 = s if stype != '!': if stype == '~': # The diff context lines are based on t1 content. When # blank lines are ignored, the new lines offsets must # be adjusted as if equivalent blocks ('~') had the # same sizes on both sides. ignoredlines += (b2 - b1) - (a2 - a1) continue delta = [] old = l1[a1:a2] new = l2[b1:b2] b1 -= ignoredlines b2 -= ignoredlines astart = contextstart(a1) bstart = contextstart(b1) prev = None if hunk: # join with the previous hunk if it falls inside the context if astart < hunk[1] + opts.context + 1: prev = hunk astart = hunk[1] bstart = hunk[3] else: for x in yieldhunk(hunk): yield x if prev: # we've joined the previous hunk, record the new ending points. hunk[1] = a2 hunk[3] = b2 delta = hunk[4] else: # create a new hunk hunk = [astart, a2, bstart, b2, delta] delta[len(delta):] = [' ' + x for x in l1[astart:a1]] delta[len(delta):] = ['-' + x for x in old] delta[len(delta):] = ['+' + x for x in new] if hunk: for x in yieldhunk(hunk): yield x def b85diff(to, tn): '''print base85-encoded binary diff''' def fmtline(line): l = len(line) if l <= 26: l = chr(ord('A') + l - 1) else: l = chr(l - 26 + ord('a') - 1) return '%c%s\n' % (l, base85.b85encode(line, True)) def chunk(text, csize=52): l = len(text) i = 0 while i < l: yield text[i:i + csize] i += csize if to is None: to = '' if tn is None: tn = '' if to == tn: return '' # TODO: deltas ret = [] ret.append('GIT binary patch\n') ret.append('literal %s\n' % len(tn)) for l in chunk(zlib.compress(tn)): ret.append(fmtline(l)) ret.append('\n') return ''.join(ret) def patchtext(bin): pos = 0 t = [] while pos < len(bin): p1, p2, l = struct.unpack(">lll", bin[pos:pos + 12]) pos += 12 t.append(bin[pos:pos + l]) pos += l return "".join(t) def patch(a, bin): if len(a) == 0: # skip over trivial delta header return util.buffer(bin, 12) return mpatch.patches(a, [bin]) # similar to difflib.SequenceMatcher.get_matching_blocks def get_matching_blocks(a, b): return [(d[0], d[2], d[1] - d[0]) for d in bdiff.blocks(a, b)] def trivialdiffheader(length): return struct.pack(">lll", 0, 0, length) def replacediffheader(oldlen, newlen): return struct.pack(">lll", 0, oldlen, newlen) patches = mpatch.patches patchedsize = mpatch.patchedsize textdiff = bdiff.bdiff