Mercurial > hg
view mercurial/changelog.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 | df41c7be16d6 |
children | ed003859f1d8 |
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# changelog.py - changelog class for mercurial # # Copyright 2005-2007 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 from .i18n import _ from .node import ( bin, hex, nullid, ) from . import ( encoding, error, revlog, util, ) _defaultextra = {'branch': 'default'} def _string_escape(text): """ >>> d = {'nl': chr(10), 'bs': chr(92), 'cr': chr(13), 'nul': chr(0)} >>> s = "ab%(nl)scd%(bs)s%(bs)sn%(nul)sab%(cr)scd%(bs)s%(nl)s" % d >>> s 'ab\\ncd\\\\\\\\n\\x00ab\\rcd\\\\\\n' >>> res = _string_escape(s) >>> s == res.decode('string_escape') True """ # subset of the string_escape codec text = text.replace('\\', '\\\\').replace('\n', '\\n').replace('\r', '\\r') return text.replace('\0', '\\0') def decodeextra(text): """ >>> sorted(decodeextra(encodeextra({'foo': 'bar', 'baz': chr(0) + '2'}) ... ).iteritems()) [('baz', '\\x002'), ('branch', 'default'), ('foo', 'bar')] >>> sorted(decodeextra(encodeextra({'foo': 'bar', ... 'baz': chr(92) + chr(0) + '2'}) ... ).iteritems()) [('baz', '\\\\\\x002'), ('branch', 'default'), ('foo', 'bar')] """ extra = _defaultextra.copy() for l in text.split('\0'): if l: if '\\0' in l: # fix up \0 without getting into trouble with \\0 l = l.replace('\\\\', '\\\\\n') l = l.replace('\\0', '\0') l = l.replace('\n', '') k, v = l.decode('string_escape').split(':', 1) extra[k] = v return extra def encodeextra(d): # keys must be sorted to produce a deterministic changelog entry items = [_string_escape('%s:%s' % (k, d[k])) for k in sorted(d)] return "\0".join(items) def stripdesc(desc): """strip trailing whitespace and leading and trailing empty lines""" return '\n'.join([l.rstrip() for l in desc.splitlines()]).strip('\n') class appender(object): '''the changelog index must be updated last on disk, so we use this class to delay writes to it''' def __init__(self, vfs, name, mode, buf): self.data = buf fp = vfs(name, mode) self.fp = fp self.offset = fp.tell() self.size = vfs.fstat(fp).st_size def end(self): return self.size + len("".join(self.data)) def tell(self): return self.offset def flush(self): pass def close(self): self.fp.close() def seek(self, offset, whence=0): '''virtual file offset spans real file and data''' if whence == 0: self.offset = offset elif whence == 1: self.offset += offset elif whence == 2: self.offset = self.end() + offset if self.offset < self.size: self.fp.seek(self.offset) def read(self, count=-1): '''only trick here is reads that span real file and data''' ret = "" if self.offset < self.size: s = self.fp.read(count) ret = s self.offset += len(s) if count > 0: count -= len(s) if count != 0: doff = self.offset - self.size self.data.insert(0, "".join(self.data)) del self.data[1:] s = self.data[0][doff:doff + count] self.offset += len(s) ret += s return ret def write(self, s): self.data.append(str(s)) self.offset += len(s) def _divertopener(opener, target): """build an opener that writes in 'target.a' instead of 'target'""" def _divert(name, mode='r'): if name != target: return opener(name, mode) return opener(name + ".a", mode) return _divert def _delayopener(opener, target, buf): """build an opener that stores chunks in 'buf' instead of 'target'""" def _delay(name, mode='r'): if name != target: return opener(name, mode) return appender(opener, name, mode, buf) return _delay class changelog(revlog.revlog): def __init__(self, opener): revlog.revlog.__init__(self, opener, "00changelog.i") if self._initempty: # changelogs don't benefit from generaldelta self.version &= ~revlog.REVLOGGENERALDELTA self._generaldelta = False self._realopener = opener self._delayed = False self._delaybuf = None self._divert = False self.filteredrevs = frozenset() def tip(self): """filtered version of revlog.tip""" for i in xrange(len(self) -1, -2, -1): if i not in self.filteredrevs: return self.node(i) def __contains__(self, rev): """filtered version of revlog.__contains__""" return (0 <= rev < len(self) and rev not in self.filteredrevs) def __iter__(self): """filtered version of revlog.__iter__""" if len(self.filteredrevs) == 0: return revlog.revlog.__iter__(self) def filterediter(): for i in xrange(len(self)): if i not in self.filteredrevs: yield i return filterediter() def revs(self, start=0, stop=None): """filtered version of revlog.revs""" for i in super(changelog, self).revs(start, stop): if i not in self.filteredrevs: yield i @util.propertycache def nodemap(self): # XXX need filtering too self.rev(self.node(0)) return self._nodecache def reachableroots(self, minroot, heads, roots, includepath=False): return self.index.reachableroots2(minroot, heads, roots, includepath) def headrevs(self): if self.filteredrevs: try: return self.index.headrevsfiltered(self.filteredrevs) # AttributeError covers non-c-extension environments and # old c extensions without filter handling. except AttributeError: return self._headrevs() return super(changelog, self).headrevs() def strip(self, *args, **kwargs): # XXX make something better than assert # We can't expect proper strip behavior if we are filtered. assert not self.filteredrevs super(changelog, self).strip(*args, **kwargs) def rev(self, node): """filtered version of revlog.rev""" r = super(changelog, self).rev(node) if r in self.filteredrevs: raise error.FilteredLookupError(hex(node), self.indexfile, _('filtered node')) return r def node(self, rev): """filtered version of revlog.node""" if rev in self.filteredrevs: raise error.FilteredIndexError(rev) return super(changelog, self).node(rev) def linkrev(self, rev): """filtered version of revlog.linkrev""" if rev in self.filteredrevs: raise error.FilteredIndexError(rev) return super(changelog, self).linkrev(rev) def parentrevs(self, rev): """filtered version of revlog.parentrevs""" if rev in self.filteredrevs: raise error.FilteredIndexError(rev) return super(changelog, self).parentrevs(rev) def flags(self, rev): """filtered version of revlog.flags""" if rev in self.filteredrevs: raise error.FilteredIndexError(rev) return super(changelog, self).flags(rev) def delayupdate(self, tr): "delay visibility of index updates to other readers" if not self._delayed: if len(self) == 0: self._divert = True if self._realopener.exists(self.indexfile + '.a'): self._realopener.unlink(self.indexfile + '.a') self.opener = _divertopener(self._realopener, self.indexfile) else: self._delaybuf = [] self.opener = _delayopener(self._realopener, self.indexfile, self._delaybuf) self._delayed = True tr.addpending('cl-%i' % id(self), self._writepending) tr.addfinalize('cl-%i' % id(self), self._finalize) def _finalize(self, tr): "finalize index updates" self._delayed = False self.opener = self._realopener # move redirected index data back into place if self._divert: assert not self._delaybuf tmpname = self.indexfile + ".a" nfile = self.opener.open(tmpname) nfile.close() self.opener.rename(tmpname, self.indexfile) elif self._delaybuf: fp = self.opener(self.indexfile, 'a') fp.write("".join(self._delaybuf)) fp.close() self._delaybuf = None self._divert = False # split when we're done self.checkinlinesize(tr) def readpending(self, file): """read index data from a "pending" file During a transaction, the actual changeset data is already stored in the main file, but not yet finalized in the on-disk index. Instead, a "pending" index is written by the transaction logic. If this function is running, we are likely in a subprocess invoked in a hook. The subprocess is informed that it is within a transaction and needs to access its content. This function will read all the index data out of the pending file and overwrite the main index.""" if not self.opener.exists(file): return # no pending data for changelog r = revlog.revlog(self.opener, file) self.index = r.index self.nodemap = r.nodemap self._nodecache = r._nodecache self._chunkcache = r._chunkcache def _writepending(self, tr): "create a file containing the unfinalized state for pretxnchangegroup" if self._delaybuf: # make a temporary copy of the index fp1 = self._realopener(self.indexfile) pendingfilename = self.indexfile + ".a" # register as a temp file to ensure cleanup on failure tr.registertmp(pendingfilename) # write existing data fp2 = self._realopener(pendingfilename, "w") fp2.write(fp1.read()) # add pending data fp2.write("".join(self._delaybuf)) fp2.close() # switch modes so finalize can simply rename self._delaybuf = None self._divert = True self.opener = _divertopener(self._realopener, self.indexfile) if self._divert: return True return False def checkinlinesize(self, tr, fp=None): if not self._delayed: revlog.revlog.checkinlinesize(self, tr, fp) def read(self, node): """ format used: nodeid\n : manifest node in ascii user\n : user, no \n or \r allowed time tz extra\n : date (time is int or float, timezone is int) : extra is metadata, encoded and separated by '\0' : older versions ignore it files\n\n : files modified by the cset, no \n or \r allowed (.*) : comment (free text, ideally utf-8) changelog v0 doesn't use extra """ text = self.revision(node) if not text: return (nullid, "", (0, 0), [], "", _defaultextra) last = text.index("\n\n") desc = encoding.tolocal(text[last + 2:]) l = text[:last].split('\n') manifest = bin(l[0]) user = encoding.tolocal(l[1]) tdata = l[2].split(' ', 2) if len(tdata) != 3: time = float(tdata[0]) try: # various tools did silly things with the time zone field. timezone = int(tdata[1]) except ValueError: timezone = 0 extra = _defaultextra else: time, timezone = float(tdata[0]), int(tdata[1]) extra = decodeextra(tdata[2]) files = l[3:] return (manifest, user, (time, timezone), files, desc, extra) def add(self, manifest, files, desc, transaction, p1, p2, user, date=None, extra=None): # Convert to UTF-8 encoded bytestrings as the very first # thing: calling any method on a localstr object will turn it # into a str object and the cached UTF-8 string is thus lost. user, desc = encoding.fromlocal(user), encoding.fromlocal(desc) user = user.strip() # An empty username or a username with a "\n" will make the # revision text contain two "\n\n" sequences -> corrupt # repository since read cannot unpack the revision. if not user: raise error.RevlogError(_("empty username")) if "\n" in user: raise error.RevlogError(_("username %s contains a newline") % repr(user)) desc = stripdesc(desc) if date: parseddate = "%d %d" % util.parsedate(date) else: parseddate = "%d %d" % util.makedate() if extra: branch = extra.get("branch") if branch in ("default", ""): del extra["branch"] elif branch in (".", "null", "tip"): raise error.RevlogError(_('the name \'%s\' is reserved') % branch) if extra: extra = encodeextra(extra) parseddate = "%s %s" % (parseddate, extra) l = [hex(manifest), user, parseddate] + sorted(files) + ["", desc] text = "\n".join(l) return self.addrevision(text, transaction, len(self), p1, p2) def branchinfo(self, rev): """return the branch name and open/close state of a revision This function exists because creating a changectx object just to access this is costly.""" extra = self.read(rev)[5] return encoding.tolocal(extra.get("branch")), 'close' in extra