Mercurial > hg-stable
view mercurial/revlog.py @ 36741:59802fa590db
setdiscovery: avoid a Yoda condition
Differential Revision: https://phab.mercurial-scm.org/D2646
| author | Martin von Zweigbergk <martinvonz@google.com> |
|---|---|
| date | Sun, 04 Mar 2018 07:40:21 -0800 |
| parents | f659a407e5ee |
| children | 981f328d6d16 |
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# revlog.py - storage back-end 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. """Storage back-end for Mercurial. This provides efficient delta storage with O(1) retrieve and append and O(changes) merge between branches. """ from __future__ import absolute_import import collections import contextlib import errno import hashlib import heapq import os import struct import zlib # import stuff from node for others to import from revlog from .node import ( bin, hex, nullid, nullrev, wdirhex, wdirid, wdirrev, ) from .i18n import _ from .thirdparty import ( attr, ) from . import ( ancestor, error, mdiff, policy, pycompat, templatefilters, util, ) parsers = policy.importmod(r'parsers') # Aliased for performance. _zlibdecompress = zlib.decompress # revlog header flags REVLOGV0 = 0 REVLOGV1 = 1 # Dummy value until file format is finalized. # Reminder: change the bounds check in revlog.__init__ when this is changed. REVLOGV2 = 0xDEAD FLAG_INLINE_DATA = (1 << 16) FLAG_GENERALDELTA = (1 << 17) REVLOG_DEFAULT_FLAGS = FLAG_INLINE_DATA REVLOG_DEFAULT_FORMAT = REVLOGV1 REVLOG_DEFAULT_VERSION = REVLOG_DEFAULT_FORMAT | REVLOG_DEFAULT_FLAGS REVLOGV1_FLAGS = FLAG_INLINE_DATA | FLAG_GENERALDELTA REVLOGV2_FLAGS = REVLOGV1_FLAGS # revlog index flags REVIDX_ISCENSORED = (1 << 15) # revision has censor metadata, must be verified REVIDX_ELLIPSIS = (1 << 14) # revision hash does not match data (narrowhg) REVIDX_EXTSTORED = (1 << 13) # revision data is stored externally REVIDX_DEFAULT_FLAGS = 0 # stable order in which flags need to be processed and their processors applied REVIDX_FLAGS_ORDER = [ REVIDX_ISCENSORED, REVIDX_ELLIPSIS, REVIDX_EXTSTORED, ] REVIDX_KNOWN_FLAGS = util.bitsfrom(REVIDX_FLAGS_ORDER) # max size of revlog with inline data _maxinline = 131072 _chunksize = 1048576 RevlogError = error.RevlogError LookupError = error.LookupError CensoredNodeError = error.CensoredNodeError ProgrammingError = error.ProgrammingError # Store flag processors (cf. 'addflagprocessor()' to register) _flagprocessors = { REVIDX_ISCENSORED: None, } def addflagprocessor(flag, processor): """Register a flag processor on a revision data flag. Invariant: - Flags need to be defined in REVIDX_KNOWN_FLAGS and REVIDX_FLAGS_ORDER. - Only one flag processor can be registered on a specific flag. - flagprocessors must be 3-tuples of functions (read, write, raw) with the following signatures: - (read) f(self, rawtext) -> text, bool - (write) f(self, text) -> rawtext, bool - (raw) f(self, rawtext) -> bool "text" is presented to the user. "rawtext" is stored in revlog data, not directly visible to the user. The boolean returned by these transforms is used to determine whether the returned text can be used for hash integrity checking. For example, if "write" returns False, then "text" is used to generate hash. If "write" returns True, that basically means "rawtext" returned by "write" should be used to generate hash. Usually, "write" and "read" return different booleans. And "raw" returns a same boolean as "write". Note: The 'raw' transform is used for changegroup generation and in some debug commands. In this case the transform only indicates whether the contents can be used for hash integrity checks. """ if not flag & REVIDX_KNOWN_FLAGS: msg = _("cannot register processor on unknown flag '%#x'.") % (flag) raise ProgrammingError(msg) if flag not in REVIDX_FLAGS_ORDER: msg = _("flag '%#x' undefined in REVIDX_FLAGS_ORDER.") % (flag) raise ProgrammingError(msg) if flag in _flagprocessors: msg = _("cannot register multiple processors on flag '%#x'.") % (flag) raise error.Abort(msg) _flagprocessors[flag] = processor def getoffset(q): return int(q >> 16) def gettype(q): return int(q & 0xFFFF) def offset_type(offset, type): if (type & ~REVIDX_KNOWN_FLAGS) != 0: raise ValueError('unknown revlog index flags') return int(int(offset) << 16 | type) _nullhash = hashlib.sha1(nullid) def hash(text, p1, p2): """generate a hash from the given text and its parent hashes This hash combines both the current file contents and its history in a manner that makes it easy to distinguish nodes with the same content in the revision graph. """ # As of now, if one of the parent node is null, p2 is null if p2 == nullid: # deep copy of a hash is faster than creating one s = _nullhash.copy() s.update(p1) else: # none of the parent nodes are nullid if p1 < p2: a = p1 b = p2 else: a = p2 b = p1 s = hashlib.sha1(a) s.update(b) s.update(text) return s.digest() def _trimchunk(revlog, revs, startidx, endidx=None): """returns revs[startidx:endidx] without empty trailing revs """ length = revlog.length if endidx is None: endidx = len(revs) # Trim empty revs at the end, but never the very first revision of a chain while endidx > 1 and endidx > startidx and length(revs[endidx - 1]) == 0: endidx -= 1 return revs[startidx:endidx] def _slicechunk(revlog, revs): """slice revs to reduce the amount of unrelated data to be read from disk. ``revs`` is sliced into groups that should be read in one time. Assume that revs are sorted. """ start = revlog.start length = revlog.length if len(revs) <= 1: yield revs return startbyte = start(revs[0]) endbyte = start(revs[-1]) + length(revs[-1]) readdata = deltachainspan = endbyte - startbyte chainpayload = sum(length(r) for r in revs) if deltachainspan: density = chainpayload / float(deltachainspan) else: density = 1.0 # Store the gaps in a heap to have them sorted by decreasing size gapsheap = [] heapq.heapify(gapsheap) prevend = None for i, rev in enumerate(revs): revstart = start(rev) revlen = length(rev) # Skip empty revisions to form larger holes if revlen == 0: continue if prevend is not None: gapsize = revstart - prevend # only consider holes that are large enough if gapsize > revlog._srmingapsize: heapq.heappush(gapsheap, (-gapsize, i)) prevend = revstart + revlen # Collect the indices of the largest holes until the density is acceptable indicesheap = [] heapq.heapify(indicesheap) while gapsheap and density < revlog._srdensitythreshold: oppgapsize, gapidx = heapq.heappop(gapsheap) heapq.heappush(indicesheap, gapidx) # the gap sizes are stored as negatives to be sorted decreasingly # by the heap readdata -= (-oppgapsize) if readdata > 0: density = chainpayload / float(readdata) else: density = 1.0 # Cut the revs at collected indices previdx = 0 while indicesheap: idx = heapq.heappop(indicesheap) chunk = _trimchunk(revlog, revs, previdx, idx) if chunk: yield chunk previdx = idx chunk = _trimchunk(revlog, revs, previdx) if chunk: yield chunk @attr.s(slots=True, frozen=True) class _deltainfo(object): distance = attr.ib() deltalen = attr.ib() data = attr.ib() base = attr.ib() chainbase = attr.ib() chainlen = attr.ib() compresseddeltalen = attr.ib() class _deltacomputer(object): def __init__(self, revlog): self.revlog = revlog def _getcandidaterevs(self, p1, p2, cachedelta): """ Provides revisions that present an interest to be diffed against, grouped by level of easiness. """ revlog = self.revlog curr = len(revlog) prev = curr - 1 p1r, p2r = revlog.rev(p1), revlog.rev(p2) # should we try to build a delta? if prev != nullrev and revlog.storedeltachains: tested = set() # This condition is true most of the time when processing # changegroup data into a generaldelta repo. The only time it # isn't true is if this is the first revision in a delta chain # or if ``format.generaldelta=true`` disabled ``lazydeltabase``. if cachedelta and revlog._generaldelta and revlog._lazydeltabase: # Assume what we received from the server is a good choice # build delta will reuse the cache yield (cachedelta[0],) tested.add(cachedelta[0]) if revlog._generaldelta: # exclude already lazy tested base if any parents = [p for p in (p1r, p2r) if p != nullrev and p not in tested] if parents and not revlog._aggressivemergedeltas: # Pick whichever parent is closer to us (to minimize the # chance of having to build a fulltext). parents = [max(parents)] tested.update(parents) yield parents if prev not in tested: # other approach failed try against prev to hopefully save us a # fulltext. yield (prev,) def buildtext(self, revinfo, fh): """Builds a fulltext version of a revision revinfo: _revisioninfo instance that contains all needed info fh: file handle to either the .i or the .d revlog file, depending on whether it is inlined or not """ btext = revinfo.btext if btext[0] is not None: return btext[0] revlog = self.revlog cachedelta = revinfo.cachedelta flags = revinfo.flags node = revinfo.node baserev = cachedelta[0] delta = cachedelta[1] # special case deltas which replace entire base; no need to decode # base revision. this neatly avoids censored bases, which throw when # they're decoded. hlen = struct.calcsize(">lll") if delta[:hlen] == mdiff.replacediffheader(revlog.rawsize(baserev), len(delta) - hlen): btext[0] = delta[hlen:] else: basetext = revlog.revision(baserev, _df=fh, raw=True) btext[0] = mdiff.patch(basetext, delta) try: res = revlog._processflags(btext[0], flags, 'read', raw=True) btext[0], validatehash = res if validatehash: revlog.checkhash(btext[0], node, p1=revinfo.p1, p2=revinfo.p2) if flags & REVIDX_ISCENSORED: raise RevlogError(_('node %s is not censored') % node) except CensoredNodeError: # must pass the censored index flag to add censored revisions if not flags & REVIDX_ISCENSORED: raise return btext[0] def _builddeltadiff(self, base, revinfo, fh): revlog = self.revlog t = self.buildtext(revinfo, fh) if revlog.iscensored(base): # deltas based on a censored revision must replace the # full content in one patch, so delta works everywhere header = mdiff.replacediffheader(revlog.rawsize(base), len(t)) delta = header + t else: ptext = revlog.revision(base, _df=fh, raw=True) delta = mdiff.textdiff(ptext, t) return delta def _builddeltainfo(self, revinfo, base, fh): # can we use the cached delta? if revinfo.cachedelta and revinfo.cachedelta[0] == base: delta = revinfo.cachedelta[1] else: delta = self._builddeltadiff(base, revinfo, fh) revlog = self.revlog header, data = revlog.compress(delta) deltalen = len(header) + len(data) chainbase = revlog.chainbase(base) offset = revlog.end(len(revlog) - 1) dist = deltalen + offset - revlog.start(chainbase) if revlog._generaldelta: deltabase = base else: deltabase = chainbase chainlen, compresseddeltalen = revlog._chaininfo(base) chainlen += 1 compresseddeltalen += deltalen return _deltainfo(dist, deltalen, (header, data), deltabase, chainbase, chainlen, compresseddeltalen) def finddeltainfo(self, revinfo, fh): """Find an acceptable delta against a candidate revision revinfo: information about the revision (instance of _revisioninfo) fh: file handle to either the .i or the .d revlog file, depending on whether it is inlined or not Returns the first acceptable candidate revision, as ordered by _getcandidaterevs """ cachedelta = revinfo.cachedelta p1 = revinfo.p1 p2 = revinfo.p2 revlog = self.revlog deltainfo = None for candidaterevs in self._getcandidaterevs(p1, p2, cachedelta): nominateddeltas = [] for candidaterev in candidaterevs: candidatedelta = self._builddeltainfo(revinfo, candidaterev, fh) if revlog._isgooddeltainfo(candidatedelta, revinfo.textlen): nominateddeltas.append(candidatedelta) if nominateddeltas: deltainfo = min(nominateddeltas, key=lambda x: x.deltalen) break return deltainfo @attr.s(slots=True, frozen=True) class _revisioninfo(object): """Information about a revision that allows building its fulltext node: expected hash of the revision p1, p2: parent revs of the revision btext: built text cache consisting of a one-element list cachedelta: (baserev, uncompressed_delta) or None flags: flags associated to the revision storage One of btext[0] or cachedelta must be set. """ node = attr.ib() p1 = attr.ib() p2 = attr.ib() btext = attr.ib() textlen = attr.ib() cachedelta = attr.ib() flags = attr.ib() # index v0: # 4 bytes: offset # 4 bytes: compressed length # 4 bytes: base rev # 4 bytes: link rev # 20 bytes: parent 1 nodeid # 20 bytes: parent 2 nodeid # 20 bytes: nodeid indexformatv0 = struct.Struct(">4l20s20s20s") indexformatv0_pack = indexformatv0.pack indexformatv0_unpack = indexformatv0.unpack class revlogoldio(object): def __init__(self): self.size = indexformatv0.size def parseindex(self, data, inline): s = self.size index = [] nodemap = {nullid: nullrev} n = off = 0 l = len(data) while off + s <= l: cur = data[off:off + s] off += s e = indexformatv0_unpack(cur) # transform to revlogv1 format e2 = (offset_type(e[0], 0), e[1], -1, e[2], e[3], nodemap.get(e[4], nullrev), nodemap.get(e[5], nullrev), e[6]) index.append(e2) nodemap[e[6]] = n n += 1 # add the magic null revision at -1 index.append((0, 0, 0, -1, -1, -1, -1, nullid)) return index, nodemap, None def packentry(self, entry, node, version, rev): if gettype(entry[0]): raise RevlogError(_('index entry flags need revlog version 1')) e2 = (getoffset(entry[0]), entry[1], entry[3], entry[4], node(entry[5]), node(entry[6]), entry[7]) return indexformatv0_pack(*e2) # index ng: # 6 bytes: offset # 2 bytes: flags # 4 bytes: compressed length # 4 bytes: uncompressed length # 4 bytes: base rev # 4 bytes: link rev # 4 bytes: parent 1 rev # 4 bytes: parent 2 rev # 32 bytes: nodeid indexformatng = struct.Struct(">Qiiiiii20s12x") indexformatng_pack = indexformatng.pack versionformat = struct.Struct(">I") versionformat_pack = versionformat.pack versionformat_unpack = versionformat.unpack # corresponds to uncompressed length of indexformatng (2 gigs, 4-byte # signed integer) _maxentrysize = 0x7fffffff class revlogio(object): def __init__(self): self.size = indexformatng.size def parseindex(self, data, inline): # call the C implementation to parse the index data index, cache = parsers.parse_index2(data, inline) return index, getattr(index, 'nodemap', None), cache def packentry(self, entry, node, version, rev): p = indexformatng_pack(*entry) if rev == 0: p = versionformat_pack(version) + p[4:] return p class revlog(object): """ the underlying revision storage object A revlog consists of two parts, an index and the revision data. The index is a file with a fixed record size containing information on each revision, including its nodeid (hash), the nodeids of its parents, the position and offset of its data within the data file, and the revision it's based on. Finally, each entry contains a linkrev entry that can serve as a pointer to external data. The revision data itself is a linear collection of data chunks. Each chunk represents a revision and is usually represented as a delta against the previous chunk. To bound lookup time, runs of deltas are limited to about 2 times the length of the original version data. This makes retrieval of a version proportional to its size, or O(1) relative to the number of revisions. Both pieces of the revlog are written to in an append-only fashion, which means we never need to rewrite a file to insert or remove data, and can use some simple techniques to avoid the need for locking while reading. If checkambig, indexfile is opened with checkambig=True at writing, to avoid file stat ambiguity. If mmaplargeindex is True, and an mmapindexthreshold is set, the index will be mmapped rather than read if it is larger than the configured threshold. """ def __init__(self, opener, indexfile, datafile=None, checkambig=False, mmaplargeindex=False): """ create a revlog object opener is a function that abstracts the file opening operation and can be used to implement COW semantics or the like. """ self.indexfile = indexfile self.datafile = datafile or (indexfile[:-2] + ".d") self.opener = opener # When True, indexfile is opened with checkambig=True at writing, to # avoid file stat ambiguity. self._checkambig = checkambig # 3-tuple of (node, rev, text) for a raw revision. self._cache = None # Maps rev to chain base rev. self._chainbasecache = util.lrucachedict(100) # 2-tuple of (offset, data) of raw data from the revlog at an offset. self._chunkcache = (0, '') # How much data to read and cache into the raw revlog data cache. self._chunkcachesize = 65536 self._maxchainlen = None self._aggressivemergedeltas = False self.index = [] # Mapping of partial identifiers to full nodes. self._pcache = {} # Mapping of revision integer to full node. self._nodecache = {nullid: nullrev} self._nodepos = None self._compengine = 'zlib' self._maxdeltachainspan = -1 self._withsparseread = False self._srdensitythreshold = 0.25 self._srmingapsize = 262144 mmapindexthreshold = None v = REVLOG_DEFAULT_VERSION opts = getattr(opener, 'options', None) if opts is not None: if 'revlogv2' in opts: # version 2 revlogs always use generaldelta. v = REVLOGV2 | FLAG_GENERALDELTA | FLAG_INLINE_DATA elif 'revlogv1' in opts: if 'generaldelta' in opts: v |= FLAG_GENERALDELTA else: v = 0 if 'chunkcachesize' in opts: self._chunkcachesize = opts['chunkcachesize'] if 'maxchainlen' in opts: self._maxchainlen = opts['maxchainlen'] if 'aggressivemergedeltas' in opts: self._aggressivemergedeltas = opts['aggressivemergedeltas'] self._lazydeltabase = bool(opts.get('lazydeltabase', False)) if 'compengine' in opts: self._compengine = opts['compengine'] if 'maxdeltachainspan' in opts: self._maxdeltachainspan = opts['maxdeltachainspan'] if mmaplargeindex and 'mmapindexthreshold' in opts: mmapindexthreshold = opts['mmapindexthreshold'] self._withsparseread = bool(opts.get('with-sparse-read', False)) if 'sparse-read-density-threshold' in opts: self._srdensitythreshold = opts['sparse-read-density-threshold'] if 'sparse-read-min-gap-size' in opts: self._srmingapsize = opts['sparse-read-min-gap-size'] if self._chunkcachesize <= 0: raise RevlogError(_('revlog chunk cache size %r is not greater ' 'than 0') % self._chunkcachesize) elif self._chunkcachesize & (self._chunkcachesize - 1): raise RevlogError(_('revlog chunk cache size %r is not a power ' 'of 2') % self._chunkcachesize) indexdata = '' self._initempty = True try: with self._indexfp() as f: if (mmapindexthreshold is not None and self.opener.fstat(f).st_size >= mmapindexthreshold): indexdata = util.buffer(util.mmapread(f)) else: indexdata = f.read() if len(indexdata) > 0: v = versionformat_unpack(indexdata[:4])[0] self._initempty = False except IOError as inst: if inst.errno != errno.ENOENT: raise self.version = v self._inline = v & FLAG_INLINE_DATA self._generaldelta = v & FLAG_GENERALDELTA flags = v & ~0xFFFF fmt = v & 0xFFFF if fmt == REVLOGV0: if flags: raise RevlogError(_('unknown flags (%#04x) in version %d ' 'revlog %s') % (flags >> 16, fmt, self.indexfile)) elif fmt == REVLOGV1: if flags & ~REVLOGV1_FLAGS: raise RevlogError(_('unknown flags (%#04x) in version %d ' 'revlog %s') % (flags >> 16, fmt, self.indexfile)) elif fmt == REVLOGV2: if flags & ~REVLOGV2_FLAGS: raise RevlogError(_('unknown flags (%#04x) in version %d ' 'revlog %s') % (flags >> 16, fmt, self.indexfile)) else: raise RevlogError(_('unknown version (%d) in revlog %s') % (fmt, self.indexfile)) self.storedeltachains = True self._io = revlogio() if self.version == REVLOGV0: self._io = revlogoldio() try: d = self._io.parseindex(indexdata, self._inline) except (ValueError, IndexError): raise RevlogError(_("index %s is corrupted") % (self.indexfile)) self.index, nodemap, self._chunkcache = d if nodemap is not None: self.nodemap = self._nodecache = nodemap if not self._chunkcache: self._chunkclear() # revnum -> (chain-length, sum-delta-length) self._chaininfocache = {} # revlog header -> revlog compressor self._decompressors = {} @util.propertycache def _compressor(self): return util.compengines[self._compengine].revlogcompressor() def _indexfp(self, mode='r'): """file object for the revlog's index file""" args = {r'mode': mode} if mode != 'r': args[r'checkambig'] = self._checkambig if mode == 'w': args[r'atomictemp'] = True return self.opener(self.indexfile, **args) def _datafp(self, mode='r'): """file object for the revlog's data file""" return self.opener(self.datafile, mode=mode) @contextlib.contextmanager def _datareadfp(self, existingfp=None): """file object suitable to read data""" if existingfp is not None: yield existingfp else: if self._inline: func = self._indexfp else: func = self._datafp with func() as fp: yield fp def tip(self): return self.node(len(self.index) - 2) def __contains__(self, rev): return 0 <= rev < len(self) def __len__(self): return len(self.index) - 1 def __iter__(self): return iter(xrange(len(self))) def revs(self, start=0, stop=None): """iterate over all rev in this revlog (from start to stop)""" step = 1 if stop is not None: if start > stop: step = -1 stop += step else: stop = len(self) return xrange(start, stop, step) @util.propertycache def nodemap(self): self.rev(self.node(0)) return self._nodecache def hasnode(self, node): try: self.rev(node) return True except KeyError: return False def clearcaches(self): self._cache = None self._chainbasecache.clear() self._chunkcache = (0, '') self._pcache = {} try: self._nodecache.clearcaches() except AttributeError: self._nodecache = {nullid: nullrev} self._nodepos = None def rev(self, node): try: return self._nodecache[node] except TypeError: raise except RevlogError: # parsers.c radix tree lookup failed if node == wdirid: raise error.WdirUnsupported raise LookupError(node, self.indexfile, _('no node')) except KeyError: # pure python cache lookup failed n = self._nodecache i = self.index p = self._nodepos if p is None: p = len(i) - 2 for r in xrange(p, -1, -1): v = i[r][7] n[v] = r if v == node: self._nodepos = r - 1 return r if node == wdirid: raise error.WdirUnsupported raise LookupError(node, self.indexfile, _('no node')) # Accessors for index entries. # First tuple entry is 8 bytes. First 6 bytes are offset. Last 2 bytes # are flags. def start(self, rev): return int(self.index[rev][0] >> 16) def flags(self, rev): return self.index[rev][0] & 0xFFFF def length(self, rev): return self.index[rev][1] def rawsize(self, rev): """return the length of the uncompressed text for a given revision""" l = self.index[rev][2] if l >= 0: return l t = self.revision(rev, raw=True) return len(t) def size(self, rev): """length of non-raw text (processed by a "read" flag processor)""" # fast path: if no "read" flag processor could change the content, # size is rawsize. note: ELLIPSIS is known to not change the content. flags = self.flags(rev) if flags & (REVIDX_KNOWN_FLAGS ^ REVIDX_ELLIPSIS) == 0: return self.rawsize(rev) return len(self.revision(rev, raw=False)) def chainbase(self, rev): base = self._chainbasecache.get(rev) if base is not None: return base index = self.index base = index[rev][3] while base != rev: rev = base base = index[rev][3] self._chainbasecache[rev] = base return base def linkrev(self, rev): return self.index[rev][4] def parentrevs(self, rev): try: entry = self.index[rev] except IndexError: if rev == wdirrev: raise error.WdirUnsupported raise return entry[5], entry[6] def node(self, rev): try: return self.index[rev][7] except IndexError: if rev == wdirrev: raise error.WdirUnsupported raise # Derived from index values. def end(self, rev): return self.start(rev) + self.length(rev) def parents(self, node): i = self.index d = i[self.rev(node)] return i[d[5]][7], i[d[6]][7] # map revisions to nodes inline def chainlen(self, rev): return self._chaininfo(rev)[0] def _chaininfo(self, rev): chaininfocache = self._chaininfocache if rev in chaininfocache: return chaininfocache[rev] index = self.index generaldelta = self._generaldelta iterrev = rev e = index[iterrev] clen = 0 compresseddeltalen = 0 while iterrev != e[3]: clen += 1 compresseddeltalen += e[1] if generaldelta: iterrev = e[3] else: iterrev -= 1 if iterrev in chaininfocache: t = chaininfocache[iterrev] clen += t[0] compresseddeltalen += t[1] break e = index[iterrev] else: # Add text length of base since decompressing that also takes # work. For cache hits the length is already included. compresseddeltalen += e[1] r = (clen, compresseddeltalen) chaininfocache[rev] = r return r def _deltachain(self, rev, stoprev=None): """Obtain the delta chain for a revision. ``stoprev`` specifies a revision to stop at. If not specified, we stop at the base of the chain. Returns a 2-tuple of (chain, stopped) where ``chain`` is a list of revs in ascending order and ``stopped`` is a bool indicating whether ``stoprev`` was hit. """ # Try C implementation. try: return self.index.deltachain(rev, stoprev, self._generaldelta) except AttributeError: pass chain = [] # Alias to prevent attribute lookup in tight loop. index = self.index generaldelta = self._generaldelta iterrev = rev e = index[iterrev] while iterrev != e[3] and iterrev != stoprev: chain.append(iterrev) if generaldelta: iterrev = e[3] else: iterrev -= 1 e = index[iterrev] if iterrev == stoprev: stopped = True else: chain.append(iterrev) stopped = False chain.reverse() return chain, stopped def ancestors(self, revs, stoprev=0, inclusive=False): """Generate the ancestors of 'revs' in reverse topological order. Does not generate revs lower than stoprev. See the documentation for ancestor.lazyancestors for more details.""" return ancestor.lazyancestors(self.parentrevs, revs, stoprev=stoprev, inclusive=inclusive) def descendants(self, revs): """Generate the descendants of 'revs' in revision order. Yield a sequence of revision numbers starting with a child of some rev in revs, i.e., each revision is *not* considered a descendant of itself. Results are ordered by revision number (a topological sort).""" first = min(revs) if first == nullrev: for i in self: yield i return seen = set(revs) for i in self.revs(start=first + 1): for x in self.parentrevs(i): if x != nullrev and x in seen: seen.add(i) yield i break def findcommonmissing(self, common=None, heads=None): """Return a tuple of the ancestors of common and the ancestors of heads that are not ancestors of common. In revset terminology, we return the tuple: ::common, (::heads) - (::common) The list is sorted by revision number, meaning it is topologically sorted. 'heads' and 'common' are both lists of node IDs. If heads is not supplied, uses all of the revlog's heads. If common is not supplied, uses nullid.""" if common is None: common = [nullid] if heads is None: heads = self.heads() common = [self.rev(n) for n in common] heads = [self.rev(n) for n in heads] # we want the ancestors, but inclusive class lazyset(object): def __init__(self, lazyvalues): self.addedvalues = set() self.lazyvalues = lazyvalues def __contains__(self, value): return value in self.addedvalues or value in self.lazyvalues def __iter__(self): added = self.addedvalues for r in added: yield r for r in self.lazyvalues: if not r in added: yield r def add(self, value): self.addedvalues.add(value) def update(self, values): self.addedvalues.update(values) has = lazyset(self.ancestors(common)) has.add(nullrev) has.update(common) # take all ancestors from heads that aren't in has missing = set() visit = collections.deque(r for r in heads if r not in has) while visit: r = visit.popleft() if r in missing: continue else: missing.add(r) for p in self.parentrevs(r): if p not in has: visit.append(p) missing = list(missing) missing.sort() return has, [self.node(miss) for miss in missing] def incrementalmissingrevs(self, common=None): """Return an object that can be used to incrementally compute the revision numbers of the ancestors of arbitrary sets that are not ancestors of common. This is an ancestor.incrementalmissingancestors object. 'common' is a list of revision numbers. If common is not supplied, uses nullrev. """ if common is None: common = [nullrev] return ancestor.incrementalmissingancestors(self.parentrevs, common) def findmissingrevs(self, common=None, heads=None): """Return the revision numbers of the ancestors of heads that are not ancestors of common. More specifically, return a list of revision numbers corresponding to nodes N such that every N satisfies the following constraints: 1. N is an ancestor of some node in 'heads' 2. N is not an ancestor of any node in 'common' The list is sorted by revision number, meaning it is topologically sorted. 'heads' and 'common' are both lists of revision numbers. If heads is not supplied, uses all of the revlog's heads. If common is not supplied, uses nullid.""" if common is None: common = [nullrev] if heads is None: heads = self.headrevs() inc = self.incrementalmissingrevs(common=common) return inc.missingancestors(heads) def findmissing(self, common=None, heads=None): """Return the ancestors of heads that are not ancestors of common. More specifically, return a list of nodes N such that every N satisfies the following constraints: 1. N is an ancestor of some node in 'heads' 2. N is not an ancestor of any node in 'common' The list is sorted by revision number, meaning it is topologically sorted. 'heads' and 'common' are both lists of node IDs. If heads is not supplied, uses all of the revlog's heads. If common is not supplied, uses nullid.""" if common is None: common = [nullid] if heads is None: heads = self.heads() common = [self.rev(n) for n in common] heads = [self.rev(n) for n in heads] inc = self.incrementalmissingrevs(common=common) return [self.node(r) for r in inc.missingancestors(heads)] def nodesbetween(self, roots=None, heads=None): """Return a topological path from 'roots' to 'heads'. Return a tuple (nodes, outroots, outheads) where 'nodes' is a topologically sorted list of all nodes N that satisfy both of these constraints: 1. N is a descendant of some node in 'roots' 2. N is an ancestor of some node in 'heads' Every node is considered to be both a descendant and an ancestor of itself, so every reachable node in 'roots' and 'heads' will be included in 'nodes'. 'outroots' is the list of reachable nodes in 'roots', i.e., the subset of 'roots' that is returned in 'nodes'. Likewise, 'outheads' is the subset of 'heads' that is also in 'nodes'. 'roots' and 'heads' are both lists of node IDs. If 'roots' is unspecified, uses nullid as the only root. If 'heads' is unspecified, uses list of all of the revlog's heads.""" nonodes = ([], [], []) if roots is not None: roots = list(roots) if not roots: return nonodes lowestrev = min([self.rev(n) for n in roots]) else: roots = [nullid] # Everybody's a descendant of nullid lowestrev = nullrev if (lowestrev == nullrev) and (heads is None): # We want _all_ the nodes! return ([self.node(r) for r in self], [nullid], list(self.heads())) if heads is None: # All nodes are ancestors, so the latest ancestor is the last # node. highestrev = len(self) - 1 # Set ancestors to None to signal that every node is an ancestor. ancestors = None # Set heads to an empty dictionary for later discovery of heads heads = {} else: heads = list(heads) if not heads: return nonodes ancestors = set() # Turn heads into a dictionary so we can remove 'fake' heads. # Also, later we will be using it to filter out the heads we can't # find from roots. heads = dict.fromkeys(heads, False) # Start at the top and keep marking parents until we're done. nodestotag = set(heads) # Remember where the top was so we can use it as a limit later. highestrev = max([self.rev(n) for n in nodestotag]) while nodestotag: # grab a node to tag n = nodestotag.pop() # Never tag nullid if n == nullid: continue # A node's revision number represents its place in a # topologically sorted list of nodes. r = self.rev(n) if r >= lowestrev: if n not in ancestors: # If we are possibly a descendant of one of the roots # and we haven't already been marked as an ancestor ancestors.add(n) # Mark as ancestor # Add non-nullid parents to list of nodes to tag. nodestotag.update([p for p in self.parents(n) if p != nullid]) elif n in heads: # We've seen it before, is it a fake head? # So it is, real heads should not be the ancestors of # any other heads. heads.pop(n) if not ancestors: return nonodes # Now that we have our set of ancestors, we want to remove any # roots that are not ancestors. # If one of the roots was nullid, everything is included anyway. if lowestrev > nullrev: # But, since we weren't, let's recompute the lowest rev to not # include roots that aren't ancestors. # Filter out roots that aren't ancestors of heads roots = [root for root in roots if root in ancestors] # Recompute the lowest revision if roots: lowestrev = min([self.rev(root) for root in roots]) else: # No more roots? Return empty list return nonodes else: # We are descending from nullid, and don't need to care about # any other roots. lowestrev = nullrev roots = [nullid] # Transform our roots list into a set. descendants = set(roots) # Also, keep the original roots so we can filter out roots that aren't # 'real' roots (i.e. are descended from other roots). roots = descendants.copy() # Our topologically sorted list of output nodes. orderedout = [] # Don't start at nullid since we don't want nullid in our output list, # and if nullid shows up in descendants, empty parents will look like # they're descendants. for r in self.revs(start=max(lowestrev, 0), stop=highestrev + 1): n = self.node(r) isdescendant = False if lowestrev == nullrev: # Everybody is a descendant of nullid isdescendant = True elif n in descendants: # n is already a descendant isdescendant = True # This check only needs to be done here because all the roots # will start being marked is descendants before the loop. if n in roots: # If n was a root, check if it's a 'real' root. p = tuple(self.parents(n)) # If any of its parents are descendants, it's not a root. if (p[0] in descendants) or (p[1] in descendants): roots.remove(n) else: p = tuple(self.parents(n)) # A node is a descendant if either of its parents are # descendants. (We seeded the dependents list with the roots # up there, remember?) if (p[0] in descendants) or (p[1] in descendants): descendants.add(n) isdescendant = True if isdescendant and ((ancestors is None) or (n in ancestors)): # Only include nodes that are both descendants and ancestors. orderedout.append(n) if (ancestors is not None) and (n in heads): # We're trying to figure out which heads are reachable # from roots. # Mark this head as having been reached heads[n] = True elif ancestors is None: # Otherwise, we're trying to discover the heads. # Assume this is a head because if it isn't, the next step # will eventually remove it. heads[n] = True # But, obviously its parents aren't. for p in self.parents(n): heads.pop(p, None) heads = [head for head, flag in heads.iteritems() if flag] roots = list(roots) assert orderedout assert roots assert heads return (orderedout, roots, heads) def headrevs(self): try: return self.index.headrevs() except AttributeError: return self._headrevs() def computephases(self, roots): return self.index.computephasesmapsets(roots) def _headrevs(self): count = len(self) if not count: return [nullrev] # we won't iter over filtered rev so nobody is a head at start ishead = [0] * (count + 1) index = self.index for r in self: ishead[r] = 1 # I may be an head e = index[r] ishead[e[5]] = ishead[e[6]] = 0 # my parent are not return [r for r, val in enumerate(ishead) if val] def heads(self, start=None, stop=None): """return the list of all nodes that have no children if start is specified, only heads that are descendants of start will be returned if stop is specified, it will consider all the revs from stop as if they had no children """ if start is None and stop is None: if not len(self): return [nullid] return [self.node(r) for r in self.headrevs()] if start is None: start = nullid if stop is None: stop = [] stoprevs = set([self.rev(n) for n in stop]) startrev = self.rev(start) reachable = {startrev} heads = {startrev} parentrevs = self.parentrevs for r in self.revs(start=startrev + 1): for p in parentrevs(r): if p in reachable: if r not in stoprevs: reachable.add(r) heads.add(r) if p in heads and p not in stoprevs: heads.remove(p) return [self.node(r) for r in heads] def children(self, node): """find the children of a given node""" c = [] p = self.rev(node) for r in self.revs(start=p + 1): prevs = [pr for pr in self.parentrevs(r) if pr != nullrev] if prevs: for pr in prevs: if pr == p: c.append(self.node(r)) elif p == nullrev: c.append(self.node(r)) return c def descendant(self, start, end): if start == nullrev: return True for i in self.descendants([start]): if i == end: return True elif i > end: break return False def commonancestorsheads(self, a, b): """calculate all the heads of the common ancestors of nodes a and b""" a, b = self.rev(a), self.rev(b) try: ancs = self.index.commonancestorsheads(a, b) except (AttributeError, OverflowError): # C implementation failed ancs = ancestor.commonancestorsheads(self.parentrevs, a, b) return pycompat.maplist(self.node, ancs) def isancestor(self, a, b): """return True if node a is an ancestor of node b The implementation of this is trivial but the use of commonancestorsheads is not.""" return a in self.commonancestorsheads(a, b) def ancestor(self, a, b): """calculate the "best" common ancestor of nodes a and b""" a, b = self.rev(a), self.rev(b) try: ancs = self.index.ancestors(a, b) except (AttributeError, OverflowError): ancs = ancestor.ancestors(self.parentrevs, a, b) if ancs: # choose a consistent winner when there's a tie return min(map(self.node, ancs)) return nullid def _match(self, id): if isinstance(id, int): # rev return self.node(id) if len(id) == 20: # possibly a binary node # odds of a binary node being all hex in ASCII are 1 in 10**25 try: node = id self.rev(node) # quick search the index return node except LookupError: pass # may be partial hex id try: # str(rev) rev = int(id) if str(rev) != id: raise ValueError if rev < 0: rev = len(self) + rev if rev < 0 or rev >= len(self): raise ValueError return self.node(rev) except (ValueError, OverflowError): pass if len(id) == 40: try: # a full hex nodeid? node = bin(id) self.rev(node) return node except (TypeError, LookupError): pass def _partialmatch(self, id): maybewdir = wdirhex.startswith(id) try: partial = self.index.partialmatch(id) if partial and self.hasnode(partial): if maybewdir: # single 'ff...' match in radix tree, ambiguous with wdir raise RevlogError return partial if maybewdir: # no 'ff...' match in radix tree, wdir identified raise error.WdirUnsupported return None except RevlogError: # parsers.c radix tree lookup gave multiple matches # fast path: for unfiltered changelog, radix tree is accurate if not getattr(self, 'filteredrevs', None): raise LookupError(id, self.indexfile, _('ambiguous identifier')) # fall through to slow path that filters hidden revisions except (AttributeError, ValueError): # we are pure python, or key was too short to search radix tree pass if id in self._pcache: return self._pcache[id] if len(id) < 40: try: # hex(node)[:...] l = len(id) // 2 # grab an even number of digits prefix = bin(id[:l * 2]) nl = [e[7] for e in self.index if e[7].startswith(prefix)] nl = [n for n in nl if hex(n).startswith(id) and self.hasnode(n)] if len(nl) > 0: if len(nl) == 1 and not maybewdir: self._pcache[id] = nl[0] return nl[0] raise LookupError(id, self.indexfile, _('ambiguous identifier')) if maybewdir: raise error.WdirUnsupported return None except TypeError: pass def lookup(self, id): """locate a node based on: - revision number or str(revision number) - nodeid or subset of hex nodeid """ n = self._match(id) if n is not None: return n n = self._partialmatch(id) if n: return n raise LookupError(id, self.indexfile, _('no match found')) def shortest(self, hexnode, minlength=1): """Find the shortest unambiguous prefix that matches hexnode.""" def isvalid(test): try: if self._partialmatch(test) is None: return False try: i = int(test) # if we are a pure int, then starting with zero will not be # confused as a rev; or, obviously, if the int is larger # than the value of the tip rev if test[0] == '0' or i > len(self): return True return False except ValueError: return True except error.RevlogError: return False except error.WdirUnsupported: # single 'ff...' match return True shortest = hexnode startlength = max(6, minlength) length = startlength while True: test = hexnode[:length] if isvalid(test): shortest = test if length == minlength or length > startlength: return shortest length -= 1 else: length += 1 if len(shortest) <= length: return shortest def cmp(self, node, text): """compare text with a given file revision returns True if text is different than what is stored. """ p1, p2 = self.parents(node) return hash(text, p1, p2) != node def _cachesegment(self, offset, data): """Add a segment to the revlog cache. Accepts an absolute offset and the data that is at that location. """ o, d = self._chunkcache # try to add to existing cache if o + len(d) == offset and len(d) + len(data) < _chunksize: self._chunkcache = o, d + data else: self._chunkcache = offset, data def _readsegment(self, offset, length, df=None): """Load a segment of raw data from the revlog. Accepts an absolute offset, length to read, and an optional existing file handle to read from. If an existing file handle is passed, it will be seeked and the original seek position will NOT be restored. Returns a str or buffer of raw byte data. """ # Cache data both forward and backward around the requested # data, in a fixed size window. This helps speed up operations # involving reading the revlog backwards. cachesize = self._chunkcachesize realoffset = offset & ~(cachesize - 1) reallength = (((offset + length + cachesize) & ~(cachesize - 1)) - realoffset) with self._datareadfp(df) as df: df.seek(realoffset) d = df.read(reallength) self._cachesegment(realoffset, d) if offset != realoffset or reallength != length: return util.buffer(d, offset - realoffset, length) return d def _getsegment(self, offset, length, df=None): """Obtain a segment of raw data from the revlog. Accepts an absolute offset, length of bytes to obtain, and an optional file handle to the already-opened revlog. If the file handle is used, it's original seek position will not be preserved. Requests for data may be returned from a cache. Returns a str or a buffer instance of raw byte data. """ o, d = self._chunkcache l = len(d) # is it in the cache? cachestart = offset - o cacheend = cachestart + length if cachestart >= 0 and cacheend <= l: if cachestart == 0 and cacheend == l: return d # avoid a copy return util.buffer(d, cachestart, cacheend - cachestart) return self._readsegment(offset, length, df=df) def _getsegmentforrevs(self, startrev, endrev, df=None): """Obtain a segment of raw data corresponding to a range of revisions. Accepts the start and end revisions and an optional already-open file handle to be used for reading. If the file handle is read, its seek position will not be preserved. Requests for data may be satisfied by a cache. Returns a 2-tuple of (offset, data) for the requested range of revisions. Offset is the integer offset from the beginning of the revlog and data is a str or buffer of the raw byte data. Callers will need to call ``self.start(rev)`` and ``self.length(rev)`` to determine where each revision's data begins and ends. """ # Inlined self.start(startrev) & self.end(endrev) for perf reasons # (functions are expensive). index = self.index istart = index[startrev] start = int(istart[0] >> 16) if startrev == endrev: end = start + istart[1] else: iend = index[endrev] end = int(iend[0] >> 16) + iend[1] if self._inline: start += (startrev + 1) * self._io.size end += (endrev + 1) * self._io.size length = end - start return start, self._getsegment(start, length, df=df) def _chunk(self, rev, df=None): """Obtain a single decompressed chunk for a revision. Accepts an integer revision and an optional already-open file handle to be used for reading. If used, the seek position of the file will not be preserved. Returns a str holding uncompressed data for the requested revision. """ return self.decompress(self._getsegmentforrevs(rev, rev, df=df)[1]) def _chunks(self, revs, df=None): """Obtain decompressed chunks for the specified revisions. Accepts an iterable of numeric revisions that are assumed to be in ascending order. Also accepts an optional already-open file handle to be used for reading. If used, the seek position of the file will not be preserved. This function is similar to calling ``self._chunk()`` multiple times, but is faster. Returns a list with decompressed data for each requested revision. """ if not revs: return [] start = self.start length = self.length inline = self._inline iosize = self._io.size buffer = util.buffer l = [] ladd = l.append if not self._withsparseread: slicedchunks = (revs,) else: slicedchunks = _slicechunk(self, revs) for revschunk in slicedchunks: firstrev = revschunk[0] # Skip trailing revisions with empty diff for lastrev in revschunk[::-1]: if length(lastrev) != 0: break try: offset, data = self._getsegmentforrevs(firstrev, lastrev, df=df) except OverflowError: # issue4215 - we can't cache a run of chunks greater than # 2G on Windows return [self._chunk(rev, df=df) for rev in revschunk] decomp = self.decompress for rev in revschunk: chunkstart = start(rev) if inline: chunkstart += (rev + 1) * iosize chunklength = length(rev) ladd(decomp(buffer(data, chunkstart - offset, chunklength))) return l def _chunkclear(self): """Clear the raw chunk cache.""" self._chunkcache = (0, '') def deltaparent(self, rev): """return deltaparent of the given revision""" base = self.index[rev][3] if base == rev: return nullrev elif self._generaldelta: return base else: return rev - 1 def revdiff(self, rev1, rev2): """return or calculate a delta between two revisions The delta calculated is in binary form and is intended to be written to revlog data directly. So this function needs raw revision data. """ if rev1 != nullrev and self.deltaparent(rev2) == rev1: return bytes(self._chunk(rev2)) return mdiff.textdiff(self.revision(rev1, raw=True), self.revision(rev2, raw=True)) def revision(self, nodeorrev, _df=None, raw=False): """return an uncompressed revision of a given node or revision number. _df - an existing file handle to read from. (internal-only) raw - an optional argument specifying if the revision data is to be treated as raw data when applying flag transforms. 'raw' should be set to True when generating changegroups or in debug commands. """ if isinstance(nodeorrev, int): rev = nodeorrev node = self.node(rev) else: node = nodeorrev rev = None cachedrev = None flags = None rawtext = None if node == nullid: return "" if self._cache: if self._cache[0] == node: # _cache only stores rawtext if raw: return self._cache[2] # duplicated, but good for perf if rev is None: rev = self.rev(node) if flags is None: flags = self.flags(rev) # no extra flags set, no flag processor runs, text = rawtext if flags == REVIDX_DEFAULT_FLAGS: return self._cache[2] # rawtext is reusable. need to run flag processor rawtext = self._cache[2] cachedrev = self._cache[1] # look up what we need to read if rawtext is None: if rev is None: rev = self.rev(node) chain, stopped = self._deltachain(rev, stoprev=cachedrev) if stopped: rawtext = self._cache[2] # drop cache to save memory self._cache = None bins = self._chunks(chain, df=_df) if rawtext is None: rawtext = bytes(bins[0]) bins = bins[1:] rawtext = mdiff.patches(rawtext, bins) self._cache = (node, rev, rawtext) if flags is None: if rev is None: rev = self.rev(node) flags = self.flags(rev) text, validatehash = self._processflags(rawtext, flags, 'read', raw=raw) if validatehash: self.checkhash(text, node, rev=rev) return text def hash(self, text, p1, p2): """Compute a node hash. Available as a function so that subclasses can replace the hash as needed. """ return hash(text, p1, p2) def _processflags(self, text, flags, operation, raw=False): """Inspect revision data flags and applies transforms defined by registered flag processors. ``text`` - the revision data to process ``flags`` - the revision flags ``operation`` - the operation being performed (read or write) ``raw`` - an optional argument describing if the raw transform should be applied. This method processes the flags in the order (or reverse order if ``operation`` is 'write') defined by REVIDX_FLAGS_ORDER, applying the flag processors registered for present flags. The order of flags defined in REVIDX_FLAGS_ORDER needs to be stable to allow non-commutativity. Returns a 2-tuple of ``(text, validatehash)`` where ``text`` is the processed text and ``validatehash`` is a bool indicating whether the returned text should be checked for hash integrity. Note: If the ``raw`` argument is set, it has precedence over the operation and will only update the value of ``validatehash``. """ # fast path: no flag processors will run if flags == 0: return text, True if not operation in ('read', 'write'): raise ProgrammingError(_("invalid '%s' operation ") % (operation)) # Check all flags are known. if flags & ~REVIDX_KNOWN_FLAGS: raise RevlogError(_("incompatible revision flag '%#x'") % (flags & ~REVIDX_KNOWN_FLAGS)) validatehash = True # Depending on the operation (read or write), the order might be # reversed due to non-commutative transforms. orderedflags = REVIDX_FLAGS_ORDER if operation == 'write': orderedflags = reversed(orderedflags) for flag in orderedflags: # If a flagprocessor has been registered for a known flag, apply the # related operation transform and update result tuple. if flag & flags: vhash = True if flag not in _flagprocessors: message = _("missing processor for flag '%#x'") % (flag) raise RevlogError(message) processor = _flagprocessors[flag] if processor is not None: readtransform, writetransform, rawtransform = processor if raw: vhash = rawtransform(self, text) elif operation == 'read': text, vhash = readtransform(self, text) else: # write operation text, vhash = writetransform(self, text) validatehash = validatehash and vhash return text, validatehash def checkhash(self, text, node, p1=None, p2=None, rev=None): """Check node hash integrity. Available as a function so that subclasses can extend hash mismatch behaviors as needed. """ if p1 is None and p2 is None: p1, p2 = self.parents(node) if node != self.hash(text, p1, p2): revornode = rev if revornode is None: revornode = templatefilters.short(hex(node)) raise RevlogError(_("integrity check failed on %s:%s") % (self.indexfile, pycompat.bytestr(revornode))) def _enforceinlinesize(self, tr, fp=None): """Check if the revlog is too big for inline and convert if so. This should be called after revisions are added to the revlog. If the revlog has grown too large to be an inline revlog, it will convert it to use multiple index and data files. """ if not self._inline or (self.start(-2) + self.length(-2)) < _maxinline: return trinfo = tr.find(self.indexfile) if trinfo is None: raise RevlogError(_("%s not found in the transaction") % self.indexfile) trindex = trinfo[2] if trindex is not None: dataoff = self.start(trindex) else: # revlog was stripped at start of transaction, use all leftover data trindex = len(self) - 1 dataoff = self.end(-2) tr.add(self.datafile, dataoff) if fp: fp.flush() fp.close() with self._datafp('w') as df: for r in self: df.write(self._getsegmentforrevs(r, r)[1]) with self._indexfp('w') as fp: self.version &= ~FLAG_INLINE_DATA self._inline = False io = self._io for i in self: e = io.packentry(self.index[i], self.node, self.version, i) fp.write(e) # the temp file replace the real index when we exit the context # manager tr.replace(self.indexfile, trindex * self._io.size) self._chunkclear() def addrevision(self, text, transaction, link, p1, p2, cachedelta=None, node=None, flags=REVIDX_DEFAULT_FLAGS, deltacomputer=None): """add a revision to the log text - the revision data to add transaction - the transaction object used for rollback link - the linkrev data to add p1, p2 - the parent nodeids of the revision cachedelta - an optional precomputed delta node - nodeid of revision; typically node is not specified, and it is computed by default as hash(text, p1, p2), however subclasses might use different hashing method (and override checkhash() in such case) flags - the known flags to set on the revision deltacomputer - an optional _deltacomputer instance shared between multiple calls """ if link == nullrev: raise RevlogError(_("attempted to add linkrev -1 to %s") % self.indexfile) if flags: node = node or self.hash(text, p1, p2) rawtext, validatehash = self._processflags(text, flags, 'write') # If the flag processor modifies the revision data, ignore any provided # cachedelta. if rawtext != text: cachedelta = None if len(rawtext) > _maxentrysize: raise RevlogError( _("%s: size of %d bytes exceeds maximum revlog storage of 2GiB") % (self.indexfile, len(rawtext))) node = node or self.hash(rawtext, p1, p2) if node in self.nodemap: return node if validatehash: self.checkhash(rawtext, node, p1=p1, p2=p2) return self.addrawrevision(rawtext, transaction, link, p1, p2, node, flags, cachedelta=cachedelta, deltacomputer=deltacomputer) def addrawrevision(self, rawtext, transaction, link, p1, p2, node, flags, cachedelta=None, deltacomputer=None): """add a raw revision with known flags, node and parents useful when reusing a revision not stored in this revlog (ex: received over wire, or read from an external bundle). """ dfh = None if not self._inline: dfh = self._datafp("a+") ifh = self._indexfp("a+") try: return self._addrevision(node, rawtext, transaction, link, p1, p2, flags, cachedelta, ifh, dfh, deltacomputer=deltacomputer) finally: if dfh: dfh.close() ifh.close() def compress(self, data): """Generate a possibly-compressed representation of data.""" if not data: return '', data compressed = self._compressor.compress(data) if compressed: # The revlog compressor added the header in the returned data. return '', compressed if data[0:1] == '\0': return '', data return 'u', data def decompress(self, data): """Decompress a revlog chunk. The chunk is expected to begin with a header identifying the format type so it can be routed to an appropriate decompressor. """ if not data: return data # Revlogs are read much more frequently than they are written and many # chunks only take microseconds to decompress, so performance is # important here. # # We can make a few assumptions about revlogs: # # 1) the majority of chunks will be compressed (as opposed to inline # raw data). # 2) decompressing *any* data will likely by at least 10x slower than # returning raw inline data. # 3) we want to prioritize common and officially supported compression # engines # # It follows that we want to optimize for "decompress compressed data # when encoded with common and officially supported compression engines" # case over "raw data" and "data encoded by less common or non-official # compression engines." That is why we have the inline lookup first # followed by the compengines lookup. # # According to `hg perfrevlogchunks`, this is ~0.5% faster for zlib # compressed chunks. And this matters for changelog and manifest reads. t = data[0:1] if t == 'x': try: return _zlibdecompress(data) except zlib.error as e: raise RevlogError(_('revlog decompress error: %s') % util.forcebytestr(e)) # '\0' is more common than 'u' so it goes first. elif t == '\0': return data elif t == 'u': return util.buffer(data, 1) try: compressor = self._decompressors[t] except KeyError: try: engine = util.compengines.forrevlogheader(t) compressor = engine.revlogcompressor() self._decompressors[t] = compressor except KeyError: raise RevlogError(_('unknown compression type %r') % t) return compressor.decompress(data) def _isgooddeltainfo(self, d, textlen): """Returns True if the given delta is good. Good means that it is within the disk span, disk size, and chain length bounds that we know to be performant.""" if d is None: return False # - 'd.distance' is the distance from the base revision -- bounding it # limits the amount of I/O we need to do. # - 'd.compresseddeltalen' is the sum of the total size of deltas we # need to apply -- bounding it limits the amount of CPU we consume. defaultmax = textlen * 4 maxdist = self._maxdeltachainspan if not maxdist: maxdist = d.distance # ensure the conditional pass maxdist = max(maxdist, defaultmax) if (d.distance > maxdist or d.deltalen > textlen or d.compresseddeltalen > textlen * 2 or (self._maxchainlen and d.chainlen > self._maxchainlen)): return False return True def _addrevision(self, node, rawtext, transaction, link, p1, p2, flags, cachedelta, ifh, dfh, alwayscache=False, deltacomputer=None): """internal function to add revisions to the log see addrevision for argument descriptions. note: "addrevision" takes non-raw text, "_addrevision" takes raw text. if "deltacomputer" is not provided or None, a defaultdeltacomputer will be used. invariants: - rawtext is optional (can be None); if not set, cachedelta must be set. if both are set, they must correspond to each other. """ if node == nullid: raise RevlogError(_("%s: attempt to add null revision") % (self.indexfile)) if node == wdirid: raise RevlogError(_("%s: attempt to add wdir revision") % (self.indexfile)) if self._inline: fh = ifh else: fh = dfh btext = [rawtext] curr = len(self) prev = curr - 1 offset = self.end(prev) p1r, p2r = self.rev(p1), self.rev(p2) # full versions are inserted when the needed deltas # become comparable to the uncompressed text if rawtext is None: textlen = mdiff.patchedsize(self.rawsize(cachedelta[0]), cachedelta[1]) else: textlen = len(rawtext) if deltacomputer is None: deltacomputer = _deltacomputer(self) revinfo = _revisioninfo(node, p1, p2, btext, textlen, cachedelta, flags) deltainfo = deltacomputer.finddeltainfo(revinfo, fh) if deltainfo is not None: base = deltainfo.base chainbase = deltainfo.chainbase data = deltainfo.data l = deltainfo.deltalen else: rawtext = deltacomputer.buildtext(revinfo, fh) data = self.compress(rawtext) l = len(data[1]) + len(data[0]) base = chainbase = curr e = (offset_type(offset, flags), l, textlen, base, link, p1r, p2r, node) self.index.insert(-1, e) self.nodemap[node] = curr entry = self._io.packentry(e, self.node, self.version, curr) self._writeentry(transaction, ifh, dfh, entry, data, link, offset) if alwayscache and rawtext is None: rawtext = deltacomputer._buildtext(revinfo, fh) if type(rawtext) == bytes: # only accept immutable objects self._cache = (node, curr, rawtext) self._chainbasecache[curr] = chainbase return node def _writeentry(self, transaction, ifh, dfh, entry, data, link, offset): # Files opened in a+ mode have inconsistent behavior on various # platforms. Windows requires that a file positioning call be made # when the file handle transitions between reads and writes. See # 3686fa2b8eee and the mixedfilemodewrapper in windows.py. On other # platforms, Python or the platform itself can be buggy. Some versions # of Solaris have been observed to not append at the end of the file # if the file was seeked to before the end. See issue4943 for more. # # We work around this issue by inserting a seek() before writing. # Note: This is likely not necessary on Python 3. ifh.seek(0, os.SEEK_END) if dfh: dfh.seek(0, os.SEEK_END) curr = len(self) - 1 if not self._inline: transaction.add(self.datafile, offset) transaction.add(self.indexfile, curr * len(entry)) if data[0]: dfh.write(data[0]) dfh.write(data[1]) ifh.write(entry) else: offset += curr * self._io.size transaction.add(self.indexfile, offset, curr) ifh.write(entry) ifh.write(data[0]) ifh.write(data[1]) self._enforceinlinesize(transaction, ifh) def addgroup(self, deltas, linkmapper, transaction, addrevisioncb=None): """ add a delta group given a set of deltas, add them to the revision log. the first delta is against its parent, which should be in our log, the rest are against the previous delta. If ``addrevisioncb`` is defined, it will be called with arguments of this revlog and the node that was added. """ nodes = [] r = len(self) end = 0 if r: end = self.end(r - 1) ifh = self._indexfp("a+") isize = r * self._io.size if self._inline: transaction.add(self.indexfile, end + isize, r) dfh = None else: transaction.add(self.indexfile, isize, r) transaction.add(self.datafile, end) dfh = self._datafp("a+") def flush(): if dfh: dfh.flush() ifh.flush() try: deltacomputer = _deltacomputer(self) # loop through our set of deltas for data in deltas: node, p1, p2, linknode, deltabase, delta, flags = data link = linkmapper(linknode) flags = flags or REVIDX_DEFAULT_FLAGS nodes.append(node) if node in self.nodemap: # this can happen if two branches make the same change continue for p in (p1, p2): if p not in self.nodemap: raise LookupError(p, self.indexfile, _('unknown parent')) if deltabase not in self.nodemap: raise LookupError(deltabase, self.indexfile, _('unknown delta base')) baserev = self.rev(deltabase) if baserev != nullrev and self.iscensored(baserev): # if base is censored, delta must be full replacement in a # single patch operation hlen = struct.calcsize(">lll") oldlen = self.rawsize(baserev) newlen = len(delta) - hlen if delta[:hlen] != mdiff.replacediffheader(oldlen, newlen): raise error.CensoredBaseError(self.indexfile, self.node(baserev)) if not flags and self._peek_iscensored(baserev, delta, flush): flags |= REVIDX_ISCENSORED # We assume consumers of addrevisioncb will want to retrieve # the added revision, which will require a call to # revision(). revision() will fast path if there is a cache # hit. So, we tell _addrevision() to always cache in this case. # We're only using addgroup() in the context of changegroup # generation so the revision data can always be handled as raw # by the flagprocessor. self._addrevision(node, None, transaction, link, p1, p2, flags, (baserev, delta), ifh, dfh, alwayscache=bool(addrevisioncb), deltacomputer=deltacomputer) if addrevisioncb: addrevisioncb(self, node) if not dfh and not self._inline: # addrevision switched from inline to conventional # reopen the index ifh.close() dfh = self._datafp("a+") ifh = self._indexfp("a+") finally: if dfh: dfh.close() ifh.close() return nodes def iscensored(self, rev): """Check if a file revision is censored.""" return False def _peek_iscensored(self, baserev, delta, flush): """Quickly check if a delta produces a censored revision.""" return False def getstrippoint(self, minlink): """find the minimum rev that must be stripped to strip the linkrev Returns a tuple containing the minimum rev and a set of all revs that have linkrevs that will be broken by this strip. """ brokenrevs = set() strippoint = len(self) heads = {} futurelargelinkrevs = set() for head in self.headrevs(): headlinkrev = self.linkrev(head) heads[head] = headlinkrev if headlinkrev >= minlink: futurelargelinkrevs.add(headlinkrev) # This algorithm involves walking down the rev graph, starting at the # heads. Since the revs are topologically sorted according to linkrev, # once all head linkrevs are below the minlink, we know there are # no more revs that could have a linkrev greater than minlink. # So we can stop walking. while futurelargelinkrevs: strippoint -= 1 linkrev = heads.pop(strippoint) if linkrev < minlink: brokenrevs.add(strippoint) else: futurelargelinkrevs.remove(linkrev) for p in self.parentrevs(strippoint): if p != nullrev: plinkrev = self.linkrev(p) heads[p] = plinkrev if plinkrev >= minlink: futurelargelinkrevs.add(plinkrev) return strippoint, brokenrevs def strip(self, minlink, transaction): """truncate the revlog on the first revision with a linkrev >= minlink This function is called when we're stripping revision minlink and its descendants from the repository. We have to remove all revisions with linkrev >= minlink, because the equivalent changelog revisions will be renumbered after the strip. So we truncate the revlog on the first of these revisions, and trust that the caller has saved the revisions that shouldn't be removed and that it'll re-add them after this truncation. """ if len(self) == 0: return rev, _ = self.getstrippoint(minlink) if rev == len(self): return # first truncate the files on disk end = self.start(rev) if not self._inline: transaction.add(self.datafile, end) end = rev * self._io.size else: end += rev * self._io.size transaction.add(self.indexfile, end) # then reset internal state in memory to forget those revisions self._cache = None self._chaininfocache = {} self._chunkclear() for x in xrange(rev, len(self)): del self.nodemap[self.node(x)] del self.index[rev:-1] def checksize(self): expected = 0 if len(self): expected = max(0, self.end(len(self) - 1)) try: with self._datafp() as f: f.seek(0, 2) actual = f.tell() dd = actual - expected except IOError as inst: if inst.errno != errno.ENOENT: raise dd = 0 try: f = self.opener(self.indexfile) f.seek(0, 2) actual = f.tell() f.close() s = self._io.size i = max(0, actual // s) di = actual - (i * s) if self._inline: databytes = 0 for r in self: databytes += max(0, self.length(r)) dd = 0 di = actual - len(self) * s - databytes except IOError as inst: if inst.errno != errno.ENOENT: raise di = 0 return (dd, di) def files(self): res = [self.indexfile] if not self._inline: res.append(self.datafile) return res DELTAREUSEALWAYS = 'always' DELTAREUSESAMEREVS = 'samerevs' DELTAREUSENEVER = 'never' DELTAREUSEFULLADD = 'fulladd' DELTAREUSEALL = {'always', 'samerevs', 'never', 'fulladd'} def clone(self, tr, destrevlog, addrevisioncb=None, deltareuse=DELTAREUSESAMEREVS, aggressivemergedeltas=None): """Copy this revlog to another, possibly with format changes. The destination revlog will contain the same revisions and nodes. However, it may not be bit-for-bit identical due to e.g. delta encoding differences. The ``deltareuse`` argument control how deltas from the existing revlog are preserved in the destination revlog. The argument can have the following values: DELTAREUSEALWAYS Deltas will always be reused (if possible), even if the destination revlog would not select the same revisions for the delta. This is the fastest mode of operation. DELTAREUSESAMEREVS Deltas will be reused if the destination revlog would pick the same revisions for the delta. This mode strikes a balance between speed and optimization. DELTAREUSENEVER Deltas will never be reused. This is the slowest mode of execution. This mode can be used to recompute deltas (e.g. if the diff/delta algorithm changes). Delta computation can be slow, so the choice of delta reuse policy can significantly affect run time. The default policy (``DELTAREUSESAMEREVS``) strikes a balance between two extremes. Deltas will be reused if they are appropriate. But if the delta could choose a better revision, it will do so. This means if you are converting a non-generaldelta revlog to a generaldelta revlog, deltas will be recomputed if the delta's parent isn't a parent of the revision. In addition to the delta policy, the ``aggressivemergedeltas`` argument controls whether to compute deltas against both parents for merges. By default, the current default is used. """ if deltareuse not in self.DELTAREUSEALL: raise ValueError(_('value for deltareuse invalid: %s') % deltareuse) if len(destrevlog): raise ValueError(_('destination revlog is not empty')) if getattr(self, 'filteredrevs', None): raise ValueError(_('source revlog has filtered revisions')) if getattr(destrevlog, 'filteredrevs', None): raise ValueError(_('destination revlog has filtered revisions')) # lazydeltabase controls whether to reuse a cached delta, if possible. oldlazydeltabase = destrevlog._lazydeltabase oldamd = destrevlog._aggressivemergedeltas try: if deltareuse == self.DELTAREUSEALWAYS: destrevlog._lazydeltabase = True elif deltareuse == self.DELTAREUSESAMEREVS: destrevlog._lazydeltabase = False destrevlog._aggressivemergedeltas = aggressivemergedeltas or oldamd populatecachedelta = deltareuse in (self.DELTAREUSEALWAYS, self.DELTAREUSESAMEREVS) deltacomputer = _deltacomputer(destrevlog) index = self.index for rev in self: entry = index[rev] # Some classes override linkrev to take filtered revs into # account. Use raw entry from index. flags = entry[0] & 0xffff linkrev = entry[4] p1 = index[entry[5]][7] p2 = index[entry[6]][7] node = entry[7] # (Possibly) reuse the delta from the revlog if allowed and # the revlog chunk is a delta. cachedelta = None rawtext = None if populatecachedelta: dp = self.deltaparent(rev) if dp != nullrev: cachedelta = (dp, str(self._chunk(rev))) if not cachedelta: rawtext = self.revision(rev, raw=True) if deltareuse == self.DELTAREUSEFULLADD: destrevlog.addrevision(rawtext, tr, linkrev, p1, p2, cachedelta=cachedelta, node=node, flags=flags, deltacomputer=deltacomputer) else: ifh = destrevlog.opener(destrevlog.indexfile, 'a+', checkambig=False) dfh = None if not destrevlog._inline: dfh = destrevlog.opener(destrevlog.datafile, 'a+') try: destrevlog._addrevision(node, rawtext, tr, linkrev, p1, p2, flags, cachedelta, ifh, dfh, deltacomputer=deltacomputer) finally: if dfh: dfh.close() ifh.close() if addrevisioncb: addrevisioncb(self, rev, node) finally: destrevlog._lazydeltabase = oldlazydeltabase destrevlog._aggressivemergedeltas = oldamd