Mercurial > hg
view mercurial/changelog.py @ 33822:42ad7cc645a4
copies: add more details to the documentation of mergecopies()
This documentation is very helpful for any developer to understand what
copytracing is and what the function does. Since this is the main function of
doing copytracing, I have also included bits about copytracing in it.
This additions are picked from a doc by Stash@Fb. So thanks to him.
Differential Revision: https://phab.mercurial-scm.org/D409
author | Pulkit Goyal <7895pulkit@gmail.com> |
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date | Wed, 16 Aug 2017 00:25:20 +0530 |
parents | 67026d65a4fc |
children | 3939b30d0cb7 |
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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 import collections 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 == util.unescapestr(res) 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 = util.unescapestr(l).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 self._end = self.size def end(self): return self._end 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(bytes(s)) self.offset += len(s) self._end += len(s) def _divertopener(opener, target): """build an opener that writes in 'target.a' instead of 'target'""" def _divert(name, mode='r', checkambig=False): 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', checkambig=False): if name != target: return opener(name, mode) return appender(opener, name, mode, buf) return _delay _changelogrevision = collections.namedtuple(u'changelogrevision', (u'manifest', u'user', u'date', u'files', u'description', u'extra')) class changelogrevision(object): """Holds results of a parsed changelog revision. Changelog revisions consist of multiple pieces of data, including the manifest node, user, and date. This object exposes a view into the parsed object. """ __slots__ = ( u'_offsets', u'_text', ) def __new__(cls, text): if not text: return _changelogrevision( manifest=nullid, user='', date=(0, 0), files=[], description='', extra=_defaultextra, ) self = super(changelogrevision, cls).__new__(cls) # We could return here and implement the following as an __init__. # But doing it here is equivalent and saves an extra function call. # 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 nl1 = text.index('\n') nl2 = text.index('\n', nl1 + 1) nl3 = text.index('\n', nl2 + 1) # The list of files may be empty. Which means nl3 is the first of the # double newline that precedes the description. if text[nl3 + 1:nl3 + 2] == '\n': doublenl = nl3 else: doublenl = text.index('\n\n', nl3 + 1) self._offsets = (nl1, nl2, nl3, doublenl) self._text = text return self @property def manifest(self): return bin(self._text[0:self._offsets[0]]) @property def user(self): off = self._offsets return encoding.tolocal(self._text[off[0] + 1:off[1]]) @property def _rawdate(self): off = self._offsets dateextra = self._text[off[1] + 1:off[2]] return dateextra.split(' ', 2)[0:2] @property def _rawextra(self): off = self._offsets dateextra = self._text[off[1] + 1:off[2]] fields = dateextra.split(' ', 2) if len(fields) != 3: return None return fields[2] @property def date(self): raw = self._rawdate time = float(raw[0]) # Various tools did silly things with the timezone. try: timezone = int(raw[1]) except ValueError: timezone = 0 return time, timezone @property def extra(self): raw = self._rawextra if raw is None: return _defaultextra return decodeextra(raw) @property def files(self): off = self._offsets if off[2] == off[3]: return [] return self._text[off[2] + 1:off[3]].split('\n') @property def description(self): return encoding.tolocal(self._text[self._offsets[3] + 2:]) class changelog(revlog.revlog): def __init__(self, opener, trypending=False): """Load a changelog revlog using an opener. If ``trypending`` is true, we attempt to load the index from a ``00changelog.i.a`` file instead of the default ``00changelog.i``. The ``00changelog.i.a`` file contains index (and possibly inline revision) data for a transaction that hasn't been finalized yet. It exists in a separate file to facilitate readers (such as hooks processes) accessing data before a transaction is finalized. """ if trypending and opener.exists('00changelog.i.a'): indexfile = '00changelog.i.a' else: indexfile = '00changelog.i' datafile = '00changelog.d' revlog.revlog.__init__(self, opener, indexfile, datafile=datafile, checkambig=True) if self._initempty: # changelogs don't benefit from generaldelta self.version &= ~revlog.FLAG_GENERALDELTA self._generaldelta = False # Delta chains for changelogs tend to be very small because entries # tend to be small and don't delta well with each. So disable delta # chains. self.storedeltachains = 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, checkambig=True) elif self._delaybuf: fp = self.opener(self.indexfile, 'a', checkambig=True) fp.write("".join(self._delaybuf)) fp.close() self._delaybuf = None self._divert = False # split when we're done self.checkinlinesize(tr) 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): """Obtain data from a parsed changelog revision. Returns a 6-tuple of: - manifest node in binary - author/user as a localstr - date as a 2-tuple of (time, timezone) - list of files - commit message as a localstr - dict of extra metadata Unless you need to access all fields, consider calling ``changelogrevision`` instead, as it is faster for partial object access. """ c = changelogrevision(self.revision(node)) return ( c.manifest, c.user, c.date, c.files, c.description, c.extra ) def changelogrevision(self, nodeorrev): """Obtain a ``changelogrevision`` for a node or revision.""" return changelogrevision(self.revision(nodeorrev)) def readfiles(self, node): """ short version of read that only returns the files modified by the cset """ text = self.revision(node) if not text: return [] last = text.index("\n\n") l = text[:last].split('\n') return l[3:] 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 def _addrevision(self, node, rawtext, transaction, *args, **kwargs): # overlay over the standard revlog._addrevision to track the new # revision on the transaction. rev = len(self) node = super(changelog, self)._addrevision(node, rawtext, transaction, *args, **kwargs) revs = transaction.changes.get('revs') if revs is not None: revs.add(rev) return node