Mercurial > hg
view hgext/remotefilelog/datapack.py @ 48576:1a84758b4fca
filemerge: remove unnecessary check for empty string
Looking at the statement just before, the string is clearly never
empty (or otherwise falsy).
Differential Revision: https://phab.mercurial-scm.org/D12011
author | Martin von Zweigbergk <martinvonz@google.com> |
---|---|
date | Thu, 20 Jan 2022 14:46:16 -0800 |
parents | d55b71393907 |
children | 6000f5b25c9b |
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from __future__ import absolute_import import struct import zlib from mercurial.node import ( hex, sha1nodeconstants, ) from mercurial.i18n import _ from mercurial import ( pycompat, util, ) from . import ( basepack, constants, shallowutil, ) NODELENGTH = 20 # The indicator value in the index for a fulltext entry. FULLTEXTINDEXMARK = -1 NOBASEINDEXMARK = -2 INDEXSUFFIX = b'.dataidx' PACKSUFFIX = b'.datapack' class datapackstore(basepack.basepackstore): INDEXSUFFIX = INDEXSUFFIX PACKSUFFIX = PACKSUFFIX def __init__(self, ui, path): super(datapackstore, self).__init__(ui, path) def getpack(self, path): return datapack(path) def get(self, name, node): raise RuntimeError(b"must use getdeltachain with datapackstore") def getmeta(self, name, node): for pack in self.packs: try: return pack.getmeta(name, node) except KeyError: pass for pack in self.refresh(): try: return pack.getmeta(name, node) except KeyError: pass raise KeyError((name, hex(node))) def getdelta(self, name, node): for pack in self.packs: try: return pack.getdelta(name, node) except KeyError: pass for pack in self.refresh(): try: return pack.getdelta(name, node) except KeyError: pass raise KeyError((name, hex(node))) def getdeltachain(self, name, node): for pack in self.packs: try: return pack.getdeltachain(name, node) except KeyError: pass for pack in self.refresh(): try: return pack.getdeltachain(name, node) except KeyError: pass raise KeyError((name, hex(node))) def add(self, name, node, data): raise RuntimeError(b"cannot add to datapackstore") class datapack(basepack.basepack): INDEXSUFFIX = INDEXSUFFIX PACKSUFFIX = PACKSUFFIX # Format is <node><delta offset><pack data offset><pack data size> # See the mutabledatapack doccomment for more details. INDEXFORMAT = b'!20siQQ' INDEXENTRYLENGTH = 40 SUPPORTED_VERSIONS = [2] def getmissing(self, keys): missing = [] for name, node in keys: value = self._find(node) if not value: missing.append((name, node)) return missing def get(self, name, node): raise RuntimeError( b"must use getdeltachain with datapack (%s:%s)" % (name, hex(node)) ) def getmeta(self, name, node): value = self._find(node) if value is None: raise KeyError((name, hex(node))) node, deltabaseoffset, offset, size = value rawentry = self._data[offset : offset + size] # see docstring of mutabledatapack for the format offset = 0 offset += struct.unpack_from(b'!H', rawentry, offset)[0] + 2 # filename offset += 40 # node, deltabase node offset += struct.unpack_from(b'!Q', rawentry, offset)[0] + 8 # delta metalen = struct.unpack_from(b'!I', rawentry, offset)[0] offset += 4 meta = shallowutil.parsepackmeta(rawentry[offset : offset + metalen]) return meta def getdelta(self, name, node): value = self._find(node) if value is None: raise KeyError((name, hex(node))) node, deltabaseoffset, offset, size = value entry = self._readentry(offset, size, getmeta=True) filename, node, deltabasenode, delta, meta = entry # If we've read a lot of data from the mmap, free some memory. self.freememory() return delta, filename, deltabasenode, meta def getdeltachain(self, name, node): value = self._find(node) if value is None: raise KeyError((name, hex(node))) params = self.params # Precompute chains chain = [value] deltabaseoffset = value[1] entrylen = self.INDEXENTRYLENGTH while ( deltabaseoffset != FULLTEXTINDEXMARK and deltabaseoffset != NOBASEINDEXMARK ): loc = params.indexstart + deltabaseoffset value = struct.unpack( self.INDEXFORMAT, self._index[loc : loc + entrylen] ) deltabaseoffset = value[1] chain.append(value) # Read chain data deltachain = [] for node, deltabaseoffset, offset, size in chain: filename, node, deltabasenode, delta = self._readentry(offset, size) deltachain.append((filename, node, filename, deltabasenode, delta)) # If we've read a lot of data from the mmap, free some memory. self.freememory() return deltachain def _readentry(self, offset, size, getmeta=False): rawentry = self._data[offset : offset + size] self._pagedin += len(rawentry) # <2 byte len> + <filename> lengthsize = 2 filenamelen = struct.unpack(b'!H', rawentry[:2])[0] filename = rawentry[lengthsize : lengthsize + filenamelen] # <20 byte node> + <20 byte deltabase> nodestart = lengthsize + filenamelen deltabasestart = nodestart + NODELENGTH node = rawentry[nodestart:deltabasestart] deltabasenode = rawentry[deltabasestart : deltabasestart + NODELENGTH] # <8 byte len> + <delta> deltastart = deltabasestart + NODELENGTH rawdeltalen = rawentry[deltastart : deltastart + 8] deltalen = struct.unpack(b'!Q', rawdeltalen)[0] delta = rawentry[deltastart + 8 : deltastart + 8 + deltalen] delta = self._decompress(delta) if getmeta: metastart = deltastart + 8 + deltalen metalen = struct.unpack_from(b'!I', rawentry, metastart)[0] rawmeta = rawentry[metastart + 4 : metastart + 4 + metalen] meta = shallowutil.parsepackmeta(rawmeta) return filename, node, deltabasenode, delta, meta else: return filename, node, deltabasenode, delta def _decompress(self, data): return zlib.decompress(data) def add(self, name, node, data): raise RuntimeError(b"cannot add to datapack (%s:%s)" % (name, node)) def _find(self, node): params = self.params fanoutkey = struct.unpack( params.fanoutstruct, node[: params.fanoutprefix] )[0] fanout = self._fanouttable start = fanout[fanoutkey] + params.indexstart indexend = self._indexend # Scan forward to find the first non-same entry, which is the upper # bound. for i in pycompat.xrange(fanoutkey + 1, params.fanoutcount): end = fanout[i] + params.indexstart if end != start: break else: end = indexend # Bisect between start and end to find node index = self._index startnode = index[start : start + NODELENGTH] endnode = index[end : end + NODELENGTH] entrylen = self.INDEXENTRYLENGTH if startnode == node: entry = index[start : start + entrylen] elif endnode == node: entry = index[end : end + entrylen] else: while start < end - entrylen: mid = start + (end - start) // 2 mid = mid - ((mid - params.indexstart) % entrylen) midnode = index[mid : mid + NODELENGTH] if midnode == node: entry = index[mid : mid + entrylen] break if node > midnode: start = mid elif node < midnode: end = mid else: return None return struct.unpack(self.INDEXFORMAT, entry) def markledger(self, ledger, options=None): for filename, node in self: ledger.markdataentry(self, filename, node) def cleanup(self, ledger): entries = ledger.sources.get(self, []) allkeys = set(self) repackedkeys = { (e.filename, e.node) for e in entries if e.datarepacked or e.gced } if len(allkeys - repackedkeys) == 0: if self.path not in ledger.created: util.unlinkpath(self.indexpath, ignoremissing=True) util.unlinkpath(self.packpath, ignoremissing=True) def __iter__(self): for f, n, deltabase, deltalen in self.iterentries(): yield f, n def iterentries(self): # Start at 1 to skip the header offset = 1 data = self._data while offset < self.datasize: oldoffset = offset # <2 byte len> + <filename> filenamelen = struct.unpack(b'!H', data[offset : offset + 2])[0] offset += 2 filename = data[offset : offset + filenamelen] offset += filenamelen # <20 byte node> node = data[offset : offset + constants.NODESIZE] offset += constants.NODESIZE # <20 byte deltabase> deltabase = data[offset : offset + constants.NODESIZE] offset += constants.NODESIZE # <8 byte len> + <delta> rawdeltalen = data[offset : offset + 8] deltalen = struct.unpack(b'!Q', rawdeltalen)[0] offset += 8 # TODO(augie): we should store a header that is the # uncompressed size. uncompressedlen = len( self._decompress(data[offset : offset + deltalen]) ) offset += deltalen # <4 byte len> + <metadata-list> metalen = struct.unpack_from(b'!I', data, offset)[0] offset += 4 + metalen yield (filename, node, deltabase, uncompressedlen) # If we've read a lot of data from the mmap, free some memory. self._pagedin += offset - oldoffset if self.freememory(): data = self._data class mutabledatapack(basepack.mutablebasepack): """A class for constructing and serializing a datapack file and index. A datapack is a pair of files that contain the revision contents for various file revisions in Mercurial. It contains only revision contents (like file contents), not any history information. It consists of two files, with the following format. All bytes are in network byte order (big endian). .datapack The pack itself is a series of revision deltas with some basic header information on each. A revision delta may be a fulltext, represented by a deltabasenode equal to the nullid. datapack = <version: 1 byte> [<revision>,...] revision = <filename len: 2 byte unsigned int> <filename> <node: 20 byte> <deltabasenode: 20 byte> <delta len: 8 byte unsigned int> <delta> <metadata-list len: 4 byte unsigned int> [1] <metadata-list> [1] metadata-list = [<metadata-item>, ...] metadata-item = <metadata-key: 1 byte> <metadata-value len: 2 byte unsigned> <metadata-value> metadata-key could be METAKEYFLAG or METAKEYSIZE or other single byte value in the future. .dataidx The index file consists of two parts, the fanout and the index. The index is a list of index entries, sorted by node (one per revision in the pack). Each entry has: - node (The 20 byte node of the entry; i.e. the commit hash, file node hash, etc) - deltabase index offset (The location in the index of the deltabase for this entry. The deltabase is the next delta in the chain, with the chain eventually terminating in a full-text, represented by a deltabase offset of -1. This lets us compute delta chains from the index, then do sequential reads from the pack if the revision are nearby on disk.) - pack entry offset (The location of this entry in the datapack) - pack content size (The on-disk length of this entry's pack data) The fanout is a quick lookup table to reduce the number of steps for bisecting the index. It is a series of 4 byte pointers to positions within the index. It has 2^16 entries, which corresponds to hash prefixes [0000, 0001,..., FFFE, FFFF]. Example: the pointer in slot 4F0A points to the index position of the first revision whose node starts with 4F0A. This saves log(2^16)=16 bisect steps. dataidx = <fanouttable> <index> fanouttable = [<index offset: 4 byte unsigned int>,...] (2^16 entries) index = [<index entry>,...] indexentry = <node: 20 byte> <deltabase location: 4 byte signed int> <pack entry offset: 8 byte unsigned int> <pack entry size: 8 byte unsigned int> [1]: new in version 1. """ INDEXSUFFIX = INDEXSUFFIX PACKSUFFIX = PACKSUFFIX # v[01] index format: <node><delta offset><pack data offset><pack data size> INDEXFORMAT = datapack.INDEXFORMAT INDEXENTRYLENGTH = datapack.INDEXENTRYLENGTH # v1 has metadata support SUPPORTED_VERSIONS = [2] def _compress(self, data): return zlib.compress(data) def add(self, name, node, deltabasenode, delta, metadata=None): # metadata is a dict, ex. {METAKEYFLAG: flag} if len(name) > 2 ** 16: raise RuntimeError(_(b"name too long %s") % name) if len(node) != 20: raise RuntimeError(_(b"node should be 20 bytes %s") % node) if node in self.entries: # The revision has already been added return # TODO: allow configurable compression delta = self._compress(delta) rawdata = b''.join( ( struct.pack(b'!H', len(name)), # unsigned 2 byte int name, node, deltabasenode, struct.pack(b'!Q', len(delta)), # unsigned 8 byte int delta, ) ) # v1 support metadata rawmeta = shallowutil.buildpackmeta(metadata) rawdata += struct.pack(b'!I', len(rawmeta)) # unsigned 4 byte rawdata += rawmeta offset = self.packfp.tell() size = len(rawdata) self.entries[node] = (deltabasenode, offset, size) self.writeraw(rawdata) def createindex(self, nodelocations, indexoffset): entries = sorted( (n, db, o, s) for n, (db, o, s) in pycompat.iteritems(self.entries) ) rawindex = b'' fmt = self.INDEXFORMAT for node, deltabase, offset, size in entries: if deltabase == sha1nodeconstants.nullid: deltabaselocation = FULLTEXTINDEXMARK else: # Instead of storing the deltabase node in the index, let's # store a pointer directly to the index entry for the deltabase. deltabaselocation = nodelocations.get( deltabase, NOBASEINDEXMARK ) entry = struct.pack(fmt, node, deltabaselocation, offset, size) rawindex += entry return rawindex