Mercurial > hg
view mercurial/pure/parsers.py @ 47490:084ed6a7c6fd
dirstate: document the dirstatetuple content
We are about to modify this, so let us document the existing code.
Differential Revision: https://phab.mercurial-scm.org/D10935
author | Pierre-Yves David <pierre-yves.david@octobus.net> |
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date | Fri, 02 Jul 2021 02:36:07 +0200 |
parents | ac60a1366a49 |
children | d4c795576aeb |
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# parsers.py - Python implementation of parsers.c # # Copyright 2009 Olivia Mackall <olivia@selenic.com> and others # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. from __future__ import absolute_import import struct import zlib from ..node import ( nullrev, sha1nodeconstants, ) from .. import ( error, pycompat, revlogutils, util, ) from ..revlogutils import nodemap as nodemaputil from ..revlogutils import constants as revlog_constants stringio = pycompat.bytesio _pack = struct.pack _unpack = struct.unpack _compress = zlib.compress _decompress = zlib.decompress # Some code below makes tuples directly because it's more convenient. However, # code outside this module should always use dirstatetuple. def dirstatetuple(*x): """the four items are: - state (one of 'n', 'a', 'r', 'm') - mode, - size, - mtime, """ # x is a tuple return x def gettype(q): return int(q & 0xFFFF) class BaseIndexObject(object): # Can I be passed to an algorithme implemented in Rust ? rust_ext_compat = 0 # Format of an index entry according to Python's `struct` language index_format = revlog_constants.INDEX_ENTRY_V1 # Size of a C unsigned long long int, platform independent big_int_size = struct.calcsize(b'>Q') # Size of a C long int, platform independent int_size = struct.calcsize(b'>i') # An empty index entry, used as a default value to be overridden, or nullrev null_item = ( 0, 0, 0, -1, -1, -1, -1, sha1nodeconstants.nullid, 0, 0, revlog_constants.COMP_MODE_INLINE, revlog_constants.COMP_MODE_INLINE, ) @util.propertycache def entry_size(self): return self.index_format.size @property def nodemap(self): msg = b"index.nodemap is deprecated, use index.[has_node|rev|get_rev]" util.nouideprecwarn(msg, b'5.3', stacklevel=2) return self._nodemap @util.propertycache def _nodemap(self): nodemap = nodemaputil.NodeMap({sha1nodeconstants.nullid: nullrev}) for r in range(0, len(self)): n = self[r][7] nodemap[n] = r return nodemap def has_node(self, node): """return True if the node exist in the index""" return node in self._nodemap def rev(self, node): """return a revision for a node If the node is unknown, raise a RevlogError""" return self._nodemap[node] def get_rev(self, node): """return a revision for a node If the node is unknown, return None""" return self._nodemap.get(node) def _stripnodes(self, start): if '_nodemap' in vars(self): for r in range(start, len(self)): n = self[r][7] del self._nodemap[n] def clearcaches(self): self.__dict__.pop('_nodemap', None) def __len__(self): return self._lgt + len(self._extra) def append(self, tup): if '_nodemap' in vars(self): self._nodemap[tup[7]] = len(self) data = self._pack_entry(len(self), tup) self._extra.append(data) def _pack_entry(self, rev, entry): assert entry[8] == 0 assert entry[9] == 0 return self.index_format.pack(*entry[:8]) def _check_index(self, i): if not isinstance(i, int): raise TypeError(b"expecting int indexes") if i < 0 or i >= len(self): raise IndexError def __getitem__(self, i): if i == -1: return self.null_item self._check_index(i) if i >= self._lgt: data = self._extra[i - self._lgt] else: index = self._calculate_index(i) data = self._data[index : index + self.entry_size] r = self._unpack_entry(i, data) if self._lgt and i == 0: offset = revlogutils.offset_type(0, gettype(r[0])) r = (offset,) + r[1:] return r def _unpack_entry(self, rev, data): r = self.index_format.unpack(data) r = r + ( 0, 0, revlog_constants.COMP_MODE_INLINE, revlog_constants.COMP_MODE_INLINE, ) return r def pack_header(self, header): """pack header information as binary""" v_fmt = revlog_constants.INDEX_HEADER return v_fmt.pack(header) def entry_binary(self, rev): """return the raw binary string representing a revision""" entry = self[rev] p = revlog_constants.INDEX_ENTRY_V1.pack(*entry[:8]) if rev == 0: p = p[revlog_constants.INDEX_HEADER.size :] return p class IndexObject(BaseIndexObject): def __init__(self, data): assert len(data) % self.entry_size == 0, ( len(data), self.entry_size, len(data) % self.entry_size, ) self._data = data self._lgt = len(data) // self.entry_size self._extra = [] def _calculate_index(self, i): return i * self.entry_size def __delitem__(self, i): if not isinstance(i, slice) or not i.stop == -1 or i.step is not None: raise ValueError(b"deleting slices only supports a:-1 with step 1") i = i.start self._check_index(i) self._stripnodes(i) if i < self._lgt: self._data = self._data[: i * self.entry_size] self._lgt = i self._extra = [] else: self._extra = self._extra[: i - self._lgt] class PersistentNodeMapIndexObject(IndexObject): """a Debug oriented class to test persistent nodemap We need a simple python object to test API and higher level behavior. See the Rust implementation for more serious usage. This should be used only through the dedicated `devel.persistent-nodemap` config. """ def nodemap_data_all(self): """Return bytes containing a full serialization of a nodemap The nodemap should be valid for the full set of revisions in the index.""" return nodemaputil.persistent_data(self) def nodemap_data_incremental(self): """Return bytes containing a incremental update to persistent nodemap This containst the data for an append-only update of the data provided in the last call to `update_nodemap_data`. """ if self._nm_root is None: return None docket = self._nm_docket changed, data = nodemaputil.update_persistent_data( self, self._nm_root, self._nm_max_idx, self._nm_docket.tip_rev ) self._nm_root = self._nm_max_idx = self._nm_docket = None return docket, changed, data def update_nodemap_data(self, docket, nm_data): """provide full block of persisted binary data for a nodemap The data are expected to come from disk. See `nodemap_data_all` for a produceur of such data.""" if nm_data is not None: self._nm_root, self._nm_max_idx = nodemaputil.parse_data(nm_data) if self._nm_root: self._nm_docket = docket else: self._nm_root = self._nm_max_idx = self._nm_docket = None class InlinedIndexObject(BaseIndexObject): def __init__(self, data, inline=0): self._data = data self._lgt = self._inline_scan(None) self._inline_scan(self._lgt) self._extra = [] def _inline_scan(self, lgt): off = 0 if lgt is not None: self._offsets = [0] * lgt count = 0 while off <= len(self._data) - self.entry_size: start = off + self.big_int_size (s,) = struct.unpack( b'>i', self._data[start : start + self.int_size], ) if lgt is not None: self._offsets[count] = off count += 1 off += self.entry_size + s if off != len(self._data): raise ValueError(b"corrupted data") return count def __delitem__(self, i): if not isinstance(i, slice) or not i.stop == -1 or i.step is not None: raise ValueError(b"deleting slices only supports a:-1 with step 1") i = i.start self._check_index(i) self._stripnodes(i) if i < self._lgt: self._offsets = self._offsets[:i] self._lgt = i self._extra = [] else: self._extra = self._extra[: i - self._lgt] def _calculate_index(self, i): return self._offsets[i] def parse_index2(data, inline, revlogv2=False): if not inline: cls = IndexObject2 if revlogv2 else IndexObject return cls(data), None cls = InlinedIndexObject return cls(data, inline), (0, data) def parse_index_cl_v2(data): return IndexChangelogV2(data), None class IndexObject2(IndexObject): index_format = revlog_constants.INDEX_ENTRY_V2 def replace_sidedata_info( self, rev, sidedata_offset, sidedata_length, offset_flags, compression_mode, ): """ Replace an existing index entry's sidedata offset and length with new ones. This cannot be used outside of the context of sidedata rewriting, inside the transaction that creates the revision `rev`. """ if rev < 0: raise KeyError self._check_index(rev) if rev < self._lgt: msg = b"cannot rewrite entries outside of this transaction" raise KeyError(msg) else: entry = list(self[rev]) entry[0] = offset_flags entry[8] = sidedata_offset entry[9] = sidedata_length entry[11] = compression_mode entry = tuple(entry) new = self._pack_entry(rev, entry) self._extra[rev - self._lgt] = new def _unpack_entry(self, rev, data): data = self.index_format.unpack(data) entry = data[:10] data_comp = data[10] & 3 sidedata_comp = (data[10] & (3 << 2)) >> 2 return entry + (data_comp, sidedata_comp) def _pack_entry(self, rev, entry): data = entry[:10] data_comp = entry[10] & 3 sidedata_comp = (entry[11] & 3) << 2 data += (data_comp | sidedata_comp,) return self.index_format.pack(*data) def entry_binary(self, rev): """return the raw binary string representing a revision""" entry = self[rev] return self._pack_entry(rev, entry) def pack_header(self, header): """pack header information as binary""" msg = 'version header should go in the docket, not the index: %d' msg %= header raise error.ProgrammingError(msg) class IndexChangelogV2(IndexObject2): index_format = revlog_constants.INDEX_ENTRY_CL_V2 def _unpack_entry(self, rev, data, r=True): items = self.index_format.unpack(data) entry = items[:3] + (rev, rev) + items[3:8] data_comp = items[8] & 3 sidedata_comp = (items[8] >> 2) & 3 return entry + (data_comp, sidedata_comp) def _pack_entry(self, rev, entry): assert entry[3] == rev, entry[3] assert entry[4] == rev, entry[4] data = entry[:3] + entry[5:10] data_comp = entry[10] & 3 sidedata_comp = (entry[11] & 3) << 2 data += (data_comp | sidedata_comp,) return self.index_format.pack(*data) def parse_index_devel_nodemap(data, inline): """like parse_index2, but alway return a PersistentNodeMapIndexObject""" return PersistentNodeMapIndexObject(data), None def parse_dirstate(dmap, copymap, st): parents = [st[:20], st[20:40]] # dereference fields so they will be local in loop format = b">cllll" e_size = struct.calcsize(format) pos1 = 40 l = len(st) # the inner loop while pos1 < l: pos2 = pos1 + e_size e = _unpack(b">cllll", st[pos1:pos2]) # a literal here is faster pos1 = pos2 + e[4] f = st[pos2:pos1] if b'\0' in f: f, c = f.split(b'\0') copymap[f] = c dmap[f] = e[:4] return parents def pack_dirstate(dmap, copymap, pl, now): now = int(now) cs = stringio() write = cs.write write(b"".join(pl)) for f, e in pycompat.iteritems(dmap): if e[0] == b'n' and e[3] == now: # The file was last modified "simultaneously" with the current # write to dirstate (i.e. within the same second for file- # systems with a granularity of 1 sec). This commonly happens # for at least a couple of files on 'update'. # The user could change the file without changing its size # within the same second. Invalidate the file's mtime in # dirstate, forcing future 'status' calls to compare the # contents of the file if the size is the same. This prevents # mistakenly treating such files as clean. e = dirstatetuple(e[0], e[1], e[2], -1) dmap[f] = e if f in copymap: f = b"%s\0%s" % (f, copymap[f]) e = _pack(b">cllll", e[0], e[1], e[2], e[3], len(f)) write(e) write(f) return cs.getvalue()