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https://github.com/facebook/sapling.git
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obsolete: introduction of obsolete markers
Markers are stored as binary records in a log structured file in .hg/store/obsstore.
This commit is contained in:
parent
a0a7fde1c9
commit
f9dd15112c
@ -7,7 +7,7 @@
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from node import bin, hex, nullid, nullrev, short
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from i18n import _
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import repo, changegroup, subrepo, discovery, pushkey
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import repo, changegroup, subrepo, discovery, pushkey, obsolete
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import changelog, dirstate, filelog, manifest, context, bookmarks, phases
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import lock, transaction, store, encoding
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import scmutil, util, extensions, hook, error, revset
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@ -192,6 +192,14 @@ class localrepository(repo.repository):
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def _phasecache(self):
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return phases.phasecache(self, self._phasedefaults)
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@storecache('obsstore')
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def obsstore(self):
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store = obsolete.obsstore()
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data = self.sopener.tryread('obsstore')
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if data:
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store.loadmarkers(data)
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return store
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@storecache('00changelog.i')
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def changelog(self):
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c = changelog.changelog(self.sopener)
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@ -983,6 +991,16 @@ class localrepository(repo.repository):
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self.store.write()
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if '_phasecache' in vars(self):
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self._phasecache.write()
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if 'obsstore' in vars(self) and self.obsstore._new:
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# XXX: transaction logic should be used here. But for
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# now rewriting the whole file is good enough.
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f = self.sopener('obsstore', 'wb', atomictemp=True)
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try:
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self.obsstore.flushmarkers(f)
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f.close()
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except: # re-raises
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f.discard()
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raise
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for k, ce in self._filecache.items():
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if k == 'dirstate':
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continue
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175
mercurial/obsolete.py
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175
mercurial/obsolete.py
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@ -0,0 +1,175 @@
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# obsolete.py - obsolete markers handling
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#
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# Copyright 2012 Pierre-Yves David <pierre-yves.david@ens-lyon.org>
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# Logilab SA <contact@logilab.fr>
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#
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# This software may be used and distributed according to the terms of the
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# GNU General Public License version 2 or any later version.
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"""Obsolete markers handling
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An obsolete marker maps an old changeset to a list of new
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changesets. If the list of new changesets is empty, the old changeset
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is said to be "killed". Otherwise, the old changeset is being
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"replaced" by the new changesets.
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Obsolete markers can be used to record and distribute changeset graph
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transformations performed by history rewriting operations, and help
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building new tools to reconciliate conflicting rewriting actions. To
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facilitate conflicts resolution, markers include various annotations
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besides old and news changeset identifiers, such as creation date or
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author name.
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Format
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------
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Markers are stored in an append-only file stored in
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'.hg/store/obsstore'.
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The file starts with a version header:
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- 1 unsigned byte: version number, starting at zero.
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The header is followed by the markers. Each marker is made of:
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- 1 unsigned byte: number of new changesets "R", could be zero.
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- 1 unsigned 32-bits integer: metadata size "M" in bytes.
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- 1 byte: a bit field. It is reserved for flags used in obsolete
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markers common operations, to avoid repeated decoding of metadata
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entries.
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- 20 bytes: obsoleted changeset identifier.
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- N*20 bytes: new changesets identifiers.
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- M bytes: metadata as a sequence of nul-terminated strings. Each
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string contains a key and a value, separated by a color ':', without
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additional encoding. Keys cannot contain '\0' or ':' and values
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cannot contain '\0'.
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"""
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import struct
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from mercurial import util
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from i18n import _
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_pack = struct.pack
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_unpack = struct.unpack
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# data used for parsing and writing
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_fmversion = 0
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_fmfixed = '>BIB20s'
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_fmnode = '20s'
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_fmfsize = struct.calcsize(_fmfixed)
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_fnodesize = struct.calcsize(_fmnode)
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def _readmarkers(data):
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"""Read and enumerate markers from raw data"""
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off = 0
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diskversion = _unpack('>B', data[off:off + 1])[0]
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off += 1
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if diskversion != _fmversion:
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raise util.Abort(_('parsing obsolete marker: unknown version %r')
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% diskversion)
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# Loop on markers
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l = len(data)
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while off + _fmfsize <= l:
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# read fixed part
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cur = data[off:off + _fmfsize]
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off += _fmfsize
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nbsuc, mdsize, flags, pre = _unpack(_fmfixed, cur)
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# read replacement
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sucs = ()
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if nbsuc:
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s = (_fnodesize * nbsuc)
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cur = data[off:off + s]
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sucs = _unpack(_fmnode * nbsuc, cur)
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off += s
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# read metadata
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# (metadata will be decoded on demand)
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metadata = data[off:off + mdsize]
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if len(metadata) != mdsize:
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raise util.Abort(_('parsing obsolete marker: metadata is too '
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'short, %d bytes expected, got %d')
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% (len(metadata), mdsize))
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off += mdsize
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yield (pre, sucs, flags, metadata)
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def encodemeta(meta):
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"""Return encoded metadata string to string mapping.
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Assume no ':' in key and no '\0' in both key and value."""
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for key, value in meta.iteritems():
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if ':' in key or '\0' in key:
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raise ValueError("':' and '\0' are forbidden in metadata key'")
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if '\0' in value:
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raise ValueError("':' are forbidden in metadata value'")
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return '\0'.join(['%s:%s' % (k, meta[k]) for k in sorted(meta)])
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def decodemeta(data):
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"""Return string to string dictionary from encoded version."""
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d = {}
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for l in data.split('\0'):
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if l:
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key, value = l.split(':')
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d[key] = value
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return d
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class obsstore(object):
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"""Store obsolete markers
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Markers can be accessed with two mappings:
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- precursors: old -> set(new)
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- successors: new -> set(old)
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"""
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def __init__(self):
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self._all = []
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# new markers to serialize
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self._new = []
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self.precursors = {}
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self.successors = {}
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def add(self, marker):
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"""Add a new marker to the store
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This marker still needs to be written to disk"""
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self._new.append(marker)
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self._load(marker)
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def loadmarkers(self, data):
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"""Load all markers in data, mark them as known."""
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for marker in _readmarkers(data):
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self._load(marker)
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def flushmarkers(self, stream):
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"""Write all markers to a stream
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After this operation, "new" markers are considered "known"."""
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self._writemarkers(stream)
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self._new[:] = []
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def _load(self, marker):
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self._all.append(marker)
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pre, sucs = marker[:2]
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self.precursors.setdefault(pre, set()).add(marker)
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for suc in sucs:
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self.successors.setdefault(suc, set()).add(marker)
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def _writemarkers(self, stream):
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# Kept separate from flushmarkers(), it will be reused for
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# markers exchange.
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stream.write(_pack('>B', _fmversion))
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for marker in self._all:
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pre, sucs, flags, metadata = marker
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nbsuc = len(sucs)
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format = _fmfixed + (_fmnode * nbsuc)
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data = [nbsuc, len(metadata), flags, pre]
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data.extend(sucs)
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stream.write(_pack(format, *data))
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stream.write(metadata)
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