Mercurial > hg
view mercurial/mdiff.py @ 39638:d292328e0143
exchangev2: fetch manifest revisions
Now that the server has support for retrieving manifest data, we can
implement the client bits to call it.
We teach the changeset fetching code to capture the manifest revisions
that are encountered on incoming changesets. We then feed this into a
new function which filters out known manifests and then batches up
manifest data requests to the server.
This is different from the previous wire protocol in a few notable
ways.
First, the client fetches manifest data separately and explicitly.
Before, we'd ask the server for data pertaining to some changesets
(via a "getbundle" command) and manifests (and files) would be sent
automatically. Providing an API for looking up just manifest data
separately gives clients much more flexibility for manifest management.
For example, a client may choose to only fetch manifest data on demand
instead of prefetching it (i.e. partial clone).
Second, we send N commands to the server for manifest retrieval instead
of 1. This property has a few nice side-effects. One is that the
deterministic nature of the requests lends itself to server-side
caching. For example, say the remote has 50,000 manifests. If the
server is configured to cache responses, each time a new commit
arrives, you will have a cache miss and need to regenerate all outgoing
data. But if you makes N requests requesting 10,000 manifests each,
a new commit will still yield cache hits on the initial, unchanged
manifest batches/requests.
A derived benefit from these properties is that resumable clone is
conceptually simpler to implement. When making a monolithic request
for all of the repository data, recovering from an interrupted clone
is hard because the server was in the driver's seat and was maintaining
state about all the data that needed transferred. With the client
driving fetching, the client can persist the set of unfetched entities
and retry/resume a fetch if something goes wrong. Or we can fetch all
data N changesets at a time and slowly build up a repository. This
approach is drastically easier to implement when we have server APIs
exposing low-level repository primitives (such as manifests and files).
We don't yet support tree manifests. But it should be possible to
implement that with the existing wire protocol command.
Differential Revision: https://phab.mercurial-scm.org/D4489
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Wed, 05 Sep 2018 09:09:57 -0700 |
parents | e7aa113b14f7 |
children | 2372284d9457 |
line wrap: on
line source
# 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 __future__ import absolute_import import re import struct import zlib from .i18n import _ from . import ( encoding, error, policy, pycompat, util, ) from .utils import dateutil _missing_newline_marker = "\\ No newline at end of file\n" bdiff = policy.importmod(r'bdiff') mpatch = policy.importmod(r'mpatch') blocks = bdiff.blocks fixws = bdiff.fixws patches = mpatch.patches patchedsize = mpatch.patchedsize textdiff = bdiff.bdiff splitnewlines = bdiff.splitnewlines 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, 'index': 0, 'ignorews': False, 'ignorewsamount': False, 'ignorewseol': False, 'ignoreblanklines': False, 'upgrade': False, 'showsimilarity': False, 'worddiff': False, 'xdiff': False, } def __init__(self, **opts): opts = pycompat.byteskwargs(opts) for k in self.defaults.keys(): 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') % pycompat.bytestr(self.context)) def copy(self, **kwargs): opts = dict((k, getattr(self, k)) for k in self.defaults) opts = pycompat.strkwargs(opts) 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') if opts.ignorewseol: text = re.sub(br'[ \t\r\f]+\n', br'\n', text) 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 hunkinrange(hunk, linerange): """Return True if `hunk` defined as (start, length) is in `linerange` defined as (lowerbound, upperbound). >>> hunkinrange((5, 10), (2, 7)) True >>> hunkinrange((5, 10), (6, 12)) True >>> hunkinrange((5, 10), (13, 17)) True >>> hunkinrange((5, 10), (3, 17)) True >>> hunkinrange((5, 10), (1, 3)) False >>> hunkinrange((5, 10), (18, 20)) False >>> hunkinrange((5, 10), (1, 5)) False >>> hunkinrange((5, 10), (15, 27)) False """ start, length = hunk lowerbound, upperbound = linerange return lowerbound < start + length and start < upperbound def blocksinrange(blocks, rangeb): """filter `blocks` like (a1, a2, b1, b2) from items outside line range `rangeb` from ``(b1, b2)`` point of view. Return `filteredblocks, rangea` where: * `filteredblocks` is list of ``block = (a1, a2, b1, b2), stype`` items of `blocks` that are inside `rangeb` from ``(b1, b2)`` point of view; a block ``(b1, b2)`` being inside `rangeb` if ``rangeb[0] < b2 and b1 < rangeb[1]``; * `rangea` is the line range w.r.t. to ``(a1, a2)`` parts of `blocks`. """ lbb, ubb = rangeb lba, uba = None, None filteredblocks = [] for block in blocks: (a1, a2, b1, b2), stype = block if lbb >= b1 and ubb <= b2 and stype == '=': # rangeb is within a single "=" hunk, restrict back linerange1 # by offsetting rangeb lba = lbb - b1 + a1 uba = ubb - b1 + a1 else: if b1 <= lbb < b2: if stype == '=': lba = a2 - (b2 - lbb) else: lba = a1 if b1 < ubb <= b2: if stype == '=': uba = a1 + (ubb - b1) else: uba = a2 if hunkinrange((b1, (b2 - b1)), rangeb): filteredblocks.append(block) if lba is None or uba is None or uba < lba: raise error.Abort(_('line range exceeds file size')) return filteredblocks, (lba, uba) def chooseblocksfunc(opts=None): if (opts is None or not opts.xdiff or not util.safehasattr(bdiff, 'xdiffblocks')): return bdiff.blocks else: return bdiff.xdiffblocks def allblocks(text1, text2, opts=None, lines1=None, lines2=None): """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. 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 or opts.ignorewseol: text1 = wsclean(opts, text1, False) text2 = wsclean(opts, text2, False) diff = chooseblocksfunc(opts)(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, binary, opts=defaultopts): """Return a unified diff as a (headers, hunks) tuple. If the diff is not null, `headers` is a list with unified diff header lines "--- <original>" and "+++ <new>" and `hunks` is a generator yielding (hunkrange, hunklines) coming from _unidiff(). Otherwise, `headers` and `hunks` are empty. Set binary=True if either a or b should be taken as a binary file. """ def datetag(date, fn=None): if not opts.git and not opts.nodates: return '\t%s' % date if fn and ' ' in fn: return '\t' return '' sentinel = [], () if not a and not b: return sentinel if opts.noprefix: aprefix = bprefix = '' else: aprefix = 'a/' bprefix = 'b/' epoch = dateutil.datestr((0, 0)) fn1 = util.pconvert(fn1) fn2 = util.pconvert(fn2) if binary: if a and b and len(a) == len(b) and a == b: return sentinel headerlines = [] hunks = (None, ['Binary file %s has changed\n' % fn1]), elif not a: without_newline = not b.endswith('\n') 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)) headerlines = [l1, l2] size = len(b) hunkrange = (0, 0, 1, size) hunklines = ["@@ -0,0 +1,%d @@\n" % size] + ["+" + e for e in b] if without_newline: hunklines[-1] += '\n' hunklines.append(_missing_newline_marker) hunks = (hunkrange, hunklines), elif not b: without_newline = not a.endswith('\n') 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)) headerlines = [l1, l2] size = len(a) hunkrange = (1, size, 0, 0) hunklines = ["@@ -1,%d +0,0 @@\n" % size] + ["-" + e for e in a] if without_newline: hunklines[-1] += '\n' hunklines.append(_missing_newline_marker) hunks = (hunkrange, hunklines), else: hunks = _unidiff(a, b, opts=opts) if not next(hunks): return sentinel headerlines = [ "--- %s%s%s" % (aprefix, fn1, datetag(ad, fn1)), "+++ %s%s%s" % (bprefix, fn2, datetag(bd, fn2)), ] return headerlines, hunks def _unidiff(t1, t2, opts=defaultopts): """Yield hunks of a headerless unified diff from t1 and t2 texts. Each hunk consists of a (hunkrange, hunklines) tuple where `hunkrange` is a tuple (s1, l1, s2, l2) representing the range information of the hunk to form the '@@ -s1,l1 +s2,l2 @@' header and `hunklines` is a list of lines of the hunk combining said header followed by line additions and deletions. The hunks are prefixed with a bool. """ l1 = splitnewlines(t1) l2 = splitnewlines(t2) 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 pycompat.xrange(astart - 1, lastpos - 1, -1): if l1[i][0:1].isalnum(): func = b' ' + l1[i].rstrip() # split long function name if ASCII. otherwise we have no # idea where the multi-byte boundary is, so just leave it. if encoding.isasciistr(func): func = func[:41] 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 hunkrange = astart, alen, bstart, blen hunklines = ( ["@@ -%d,%d +%d,%d @@%s\n" % (hunkrange + (func,))] + delta + [' ' + l1[x] for x in pycompat.xrange(a2, aend)] ) # If either file ends without a newline and the last line of # that file is part of a hunk, a marker is printed. If the # last line of both files is identical and neither ends in # a newline, print only one marker. That's the only case in # which the hunk can end in a shared line without a newline. skip = False if not t1.endswith('\n') and astart + alen == len(l1) + 1: for i in pycompat.xrange(len(hunklines) - 1, -1, -1): if hunklines[i].startswith(('-', ' ')): if hunklines[i].startswith(' '): skip = True hunklines[i] += '\n' hunklines.insert(i + 1, _missing_newline_marker) break if not skip and not t2.endswith('\n') and bstart + blen == len(l2) + 1: for i in pycompat.xrange(len(hunklines) - 1, -1, -1): if hunklines[i].startswith('+'): hunklines[i] += '\n' hunklines.insert(i + 1, _missing_newline_marker) break yield hunkrange, hunklines # 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 has_hunks = False 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: if not has_hunks: has_hunks = True yield True 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: if not has_hunks: has_hunks = True yield True for x in yieldhunk(hunk): yield x elif not has_hunks: yield False def b85diff(to, tn): '''print base85-encoded binary diff''' def fmtline(line): l = len(line) if l <= 26: l = pycompat.bytechr(ord('A') + l - 1) else: l = pycompat.bytechr(l - 26 + ord('a') - 1) return '%c%s\n' % (l, util.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 %d\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) if length else '' def replacediffheader(oldlen, newlen): return struct.pack(">lll", 0, oldlen, newlen)