##// END OF EJS Templates
filelog: open the writing context a bit earlier in `addgroup`...
filelog: open the writing context a bit earlier in `addgroup` This is a small change made ahead of the next patch for clarification. Differential Revision: https://phab.mercurial-scm.org/D11269

File last commit:

r48627:c02ce6de stable
r48628:436932c2 stable
Show More
rewrite.py
802 lines | 26.2 KiB | text/x-python | PythonLexer
# censor code related to censoring revision
# coding: utf8
#
# Copyright 2021 Pierre-Yves David <pierre-yves.david@octobus.net>
# Copyright 2015 Google, Inc <martinvonz@google.com>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
import binascii
import contextlib
import os
import struct
from ..node import (
nullrev,
)
from .constants import (
COMP_MODE_PLAIN,
ENTRY_DATA_COMPRESSED_LENGTH,
ENTRY_DATA_COMPRESSION_MODE,
ENTRY_DATA_OFFSET,
ENTRY_DATA_UNCOMPRESSED_LENGTH,
ENTRY_DELTA_BASE,
ENTRY_LINK_REV,
ENTRY_NODE_ID,
ENTRY_PARENT_1,
ENTRY_PARENT_2,
ENTRY_SIDEDATA_COMPRESSED_LENGTH,
ENTRY_SIDEDATA_COMPRESSION_MODE,
ENTRY_SIDEDATA_OFFSET,
REVLOGV0,
REVLOGV1,
)
from ..i18n import _
from .. import (
error,
pycompat,
revlogutils,
util,
)
from ..utils import (
storageutil,
)
from . import (
constants,
deltas,
)
def v1_censor(rl, tr, censornode, tombstone=b''):
"""censors a revision in a "version 1" revlog"""
assert rl._format_version == constants.REVLOGV1, rl._format_version
# avoid cycle
from .. import revlog
censorrev = rl.rev(censornode)
tombstone = storageutil.packmeta({b'censored': tombstone}, b'')
# Rewriting the revlog in place is hard. Our strategy for censoring is
# to create a new revlog, copy all revisions to it, then replace the
# revlogs on transaction close.
#
# This is a bit dangerous. We could easily have a mismatch of state.
newrl = revlog.revlog(
rl.opener,
target=rl.target,
radix=rl.radix,
postfix=b'tmpcensored',
censorable=True,
)
newrl._format_version = rl._format_version
newrl._format_flags = rl._format_flags
newrl._generaldelta = rl._generaldelta
newrl._parse_index = rl._parse_index
for rev in rl.revs():
node = rl.node(rev)
p1, p2 = rl.parents(node)
if rev == censorrev:
newrl.addrawrevision(
tombstone,
tr,
rl.linkrev(censorrev),
p1,
p2,
censornode,
constants.REVIDX_ISCENSORED,
)
if newrl.deltaparent(rev) != nullrev:
m = _(b'censored revision stored as delta; cannot censor')
h = _(
b'censoring of revlogs is not fully implemented;'
b' please report this bug'
)
raise error.Abort(m, hint=h)
continue
if rl.iscensored(rev):
if rl.deltaparent(rev) != nullrev:
m = _(
b'cannot censor due to censored '
b'revision having delta stored'
)
raise error.Abort(m)
rawtext = rl._chunk(rev)
else:
rawtext = rl.rawdata(rev)
newrl.addrawrevision(
rawtext, tr, rl.linkrev(rev), p1, p2, node, rl.flags(rev)
)
tr.addbackup(rl._indexfile, location=b'store')
if not rl._inline:
tr.addbackup(rl._datafile, location=b'store')
rl.opener.rename(newrl._indexfile, rl._indexfile)
if not rl._inline:
rl.opener.rename(newrl._datafile, rl._datafile)
rl.clearcaches()
rl._loadindex()
def v2_censor(revlog, tr, censornode, tombstone=b''):
"""censors a revision in a "version 2" revlog"""
assert revlog._format_version != REVLOGV0, revlog._format_version
assert revlog._format_version != REVLOGV1, revlog._format_version
censor_revs = {revlog.rev(censornode)}
_rewrite_v2(revlog, tr, censor_revs, tombstone)
def _rewrite_v2(revlog, tr, censor_revs, tombstone=b''):
"""rewrite a revlog to censor some of its content
General principle
We create new revlog files (index/data/sidedata) to copy the content of
the existing data without the censored data.
We need to recompute new delta for any revision that used the censored
revision as delta base. As the cumulative size of the new delta may be
large, we store them in a temporary file until they are stored in their
final destination.
All data before the censored data can be blindly copied. The rest needs
to be copied as we go and the associated index entry needs adjustement.
"""
assert revlog._format_version != REVLOGV0, revlog._format_version
assert revlog._format_version != REVLOGV1, revlog._format_version
old_index = revlog.index
docket = revlog._docket
tombstone = storageutil.packmeta({b'censored': tombstone}, b'')
first_excl_rev = min(censor_revs)
first_excl_entry = revlog.index[first_excl_rev]
index_cutoff = revlog.index.entry_size * first_excl_rev
data_cutoff = first_excl_entry[ENTRY_DATA_OFFSET] >> 16
sidedata_cutoff = revlog.sidedata_cut_off(first_excl_rev)
with pycompat.unnamedtempfile(mode=b"w+b") as tmp_storage:
# rev → (new_base, data_start, data_end, compression_mode)
rewritten_entries = _precompute_rewritten_delta(
revlog,
old_index,
censor_revs,
tmp_storage,
)
all_files = _setup_new_files(
revlog,
index_cutoff,
data_cutoff,
sidedata_cutoff,
)
# we dont need to open the old index file since its content already
# exist in a usable form in `old_index`.
with all_files() as open_files:
(
old_data_file,
old_sidedata_file,
new_index_file,
new_data_file,
new_sidedata_file,
) = open_files
# writing the censored revision
# Writing all subsequent revisions
for rev in range(first_excl_rev, len(old_index)):
if rev in censor_revs:
_rewrite_censor(
revlog,
old_index,
open_files,
rev,
tombstone,
)
else:
_rewrite_simple(
revlog,
old_index,
open_files,
rev,
rewritten_entries,
tmp_storage,
)
docket.write(transaction=None, stripping=True)
def _precompute_rewritten_delta(
revlog,
old_index,
excluded_revs,
tmp_storage,
):
"""Compute new delta for revisions whose delta is based on revision that
will not survive as is.
Return a mapping: {rev → (new_base, data_start, data_end, compression_mode)}
"""
dc = deltas.deltacomputer(revlog)
rewritten_entries = {}
first_excl_rev = min(excluded_revs)
with revlog._segmentfile._open_read() as dfh:
for rev in range(first_excl_rev, len(old_index)):
if rev in excluded_revs:
# this revision will be preserved as is, so we don't need to
# consider recomputing a delta.
continue
entry = old_index[rev]
if entry[ENTRY_DELTA_BASE] not in excluded_revs:
continue
# This is a revision that use the censored revision as the base
# for its delta. We need a need new deltas
if entry[ENTRY_DATA_UNCOMPRESSED_LENGTH] == 0:
# this revision is empty, we can delta against nullrev
rewritten_entries[rev] = (nullrev, 0, 0, COMP_MODE_PLAIN)
else:
text = revlog.rawdata(rev, _df=dfh)
info = revlogutils.revisioninfo(
node=entry[ENTRY_NODE_ID],
p1=revlog.node(entry[ENTRY_PARENT_1]),
p2=revlog.node(entry[ENTRY_PARENT_2]),
btext=[text],
textlen=len(text),
cachedelta=None,
flags=entry[ENTRY_DATA_OFFSET] & 0xFFFF,
)
d = dc.finddeltainfo(
info, dfh, excluded_bases=excluded_revs, target_rev=rev
)
default_comp = revlog._docket.default_compression_header
comp_mode, d = deltas.delta_compression(default_comp, d)
# using `tell` is a bit lazy, but we are not here for speed
start = tmp_storage.tell()
tmp_storage.write(d.data[1])
end = tmp_storage.tell()
rewritten_entries[rev] = (d.base, start, end, comp_mode)
return rewritten_entries
def _setup_new_files(
revlog,
index_cutoff,
data_cutoff,
sidedata_cutoff,
):
"""
return a context manager to open all the relevant files:
- old_data_file,
- old_sidedata_file,
- new_index_file,
- new_data_file,
- new_sidedata_file,
The old_index_file is not here because it is accessed through the
`old_index` object if the caller function.
"""
docket = revlog._docket
old_index_filepath = revlog.opener.join(docket.index_filepath())
old_data_filepath = revlog.opener.join(docket.data_filepath())
old_sidedata_filepath = revlog.opener.join(docket.sidedata_filepath())
new_index_filepath = revlog.opener.join(docket.new_index_file())
new_data_filepath = revlog.opener.join(docket.new_data_file())
new_sidedata_filepath = revlog.opener.join(docket.new_sidedata_file())
util.copyfile(old_index_filepath, new_index_filepath, nb_bytes=index_cutoff)
util.copyfile(old_data_filepath, new_data_filepath, nb_bytes=data_cutoff)
util.copyfile(
old_sidedata_filepath,
new_sidedata_filepath,
nb_bytes=sidedata_cutoff,
)
revlog.opener.register_file(docket.index_filepath())
revlog.opener.register_file(docket.data_filepath())
revlog.opener.register_file(docket.sidedata_filepath())
docket.index_end = index_cutoff
docket.data_end = data_cutoff
docket.sidedata_end = sidedata_cutoff
# reload the revlog internal information
revlog.clearcaches()
revlog._loadindex(docket=docket)
@contextlib.contextmanager
def all_files_opener():
# hide opening in an helper function to please check-code, black
# and various python version at the same time
with open(old_data_filepath, 'rb') as old_data_file:
with open(old_sidedata_filepath, 'rb') as old_sidedata_file:
with open(new_index_filepath, 'r+b') as new_index_file:
with open(new_data_filepath, 'r+b') as new_data_file:
with open(
new_sidedata_filepath, 'r+b'
) as new_sidedata_file:
new_index_file.seek(0, os.SEEK_END)
assert new_index_file.tell() == index_cutoff
new_data_file.seek(0, os.SEEK_END)
assert new_data_file.tell() == data_cutoff
new_sidedata_file.seek(0, os.SEEK_END)
assert new_sidedata_file.tell() == sidedata_cutoff
yield (
old_data_file,
old_sidedata_file,
new_index_file,
new_data_file,
new_sidedata_file,
)
return all_files_opener
def _rewrite_simple(
revlog,
old_index,
all_files,
rev,
rewritten_entries,
tmp_storage,
):
"""append a normal revision to the index after the rewritten one(s)"""
(
old_data_file,
old_sidedata_file,
new_index_file,
new_data_file,
new_sidedata_file,
) = all_files
entry = old_index[rev]
flags = entry[ENTRY_DATA_OFFSET] & 0xFFFF
old_data_offset = entry[ENTRY_DATA_OFFSET] >> 16
if rev not in rewritten_entries:
old_data_file.seek(old_data_offset)
new_data_size = entry[ENTRY_DATA_COMPRESSED_LENGTH]
new_data = old_data_file.read(new_data_size)
data_delta_base = entry[ENTRY_DELTA_BASE]
d_comp_mode = entry[ENTRY_DATA_COMPRESSION_MODE]
else:
(
data_delta_base,
start,
end,
d_comp_mode,
) = rewritten_entries[rev]
new_data_size = end - start
tmp_storage.seek(start)
new_data = tmp_storage.read(new_data_size)
# It might be faster to group continuous read/write operation,
# however, this is censor, an operation that is not focussed
# around stellar performance. So I have not written this
# optimisation yet.
new_data_offset = new_data_file.tell()
new_data_file.write(new_data)
sidedata_size = entry[ENTRY_SIDEDATA_COMPRESSED_LENGTH]
new_sidedata_offset = new_sidedata_file.tell()
if 0 < sidedata_size:
old_sidedata_offset = entry[ENTRY_SIDEDATA_OFFSET]
old_sidedata_file.seek(old_sidedata_offset)
new_sidedata = old_sidedata_file.read(sidedata_size)
new_sidedata_file.write(new_sidedata)
data_uncompressed_length = entry[ENTRY_DATA_UNCOMPRESSED_LENGTH]
sd_com_mode = entry[ENTRY_SIDEDATA_COMPRESSION_MODE]
assert data_delta_base <= rev, (data_delta_base, rev)
new_entry = revlogutils.entry(
flags=flags,
data_offset=new_data_offset,
data_compressed_length=new_data_size,
data_uncompressed_length=data_uncompressed_length,
data_delta_base=data_delta_base,
link_rev=entry[ENTRY_LINK_REV],
parent_rev_1=entry[ENTRY_PARENT_1],
parent_rev_2=entry[ENTRY_PARENT_2],
node_id=entry[ENTRY_NODE_ID],
sidedata_offset=new_sidedata_offset,
sidedata_compressed_length=sidedata_size,
data_compression_mode=d_comp_mode,
sidedata_compression_mode=sd_com_mode,
)
revlog.index.append(new_entry)
entry_bin = revlog.index.entry_binary(rev)
new_index_file.write(entry_bin)
revlog._docket.index_end = new_index_file.tell()
revlog._docket.data_end = new_data_file.tell()
revlog._docket.sidedata_end = new_sidedata_file.tell()
def _rewrite_censor(
revlog,
old_index,
all_files,
rev,
tombstone,
):
"""rewrite and append a censored revision"""
(
old_data_file,
old_sidedata_file,
new_index_file,
new_data_file,
new_sidedata_file,
) = all_files
entry = old_index[rev]
# XXX consider trying the default compression too
new_data_size = len(tombstone)
new_data_offset = new_data_file.tell()
new_data_file.write(tombstone)
# we are not adding any sidedata as they might leak info about the censored version
link_rev = entry[ENTRY_LINK_REV]
p1 = entry[ENTRY_PARENT_1]
p2 = entry[ENTRY_PARENT_2]
new_entry = revlogutils.entry(
flags=constants.REVIDX_ISCENSORED,
data_offset=new_data_offset,
data_compressed_length=new_data_size,
data_uncompressed_length=new_data_size,
data_delta_base=rev,
link_rev=link_rev,
parent_rev_1=p1,
parent_rev_2=p2,
node_id=entry[ENTRY_NODE_ID],
sidedata_offset=0,
sidedata_compressed_length=0,
data_compression_mode=COMP_MODE_PLAIN,
sidedata_compression_mode=COMP_MODE_PLAIN,
)
revlog.index.append(new_entry)
entry_bin = revlog.index.entry_binary(rev)
new_index_file.write(entry_bin)
revlog._docket.index_end = new_index_file.tell()
revlog._docket.data_end = new_data_file.tell()
def _get_filename_from_filelog_index(path):
# Drop the extension and the `data/` prefix
path_part = path.rsplit(b'.', 1)[0].split(b'/', 1)
if len(path_part) < 2:
msg = _(b"cannot recognize filelog from filename: '%s'")
msg %= path
raise error.Abort(msg)
return path_part[1]
def _filelog_from_filename(repo, path):
"""Returns the filelog for the given `path`. Stolen from `engine.py`"""
from .. import filelog # avoid cycle
fl = filelog.filelog(repo.svfs, path)
return fl
def _write_swapped_parents(repo, rl, rev, offset, fp):
"""Swaps p1 and p2 and overwrites the revlog entry for `rev` in `fp`"""
from ..pure import parsers # avoid cycle
if repo._currentlock(repo._lockref) is None:
# Let's be paranoid about it
msg = "repo needs to be locked to rewrite parents"
raise error.ProgrammingError(msg)
index_format = parsers.IndexObject.index_format
entry = rl.index[rev]
new_entry = list(entry)
new_entry[5], new_entry[6] = entry[6], entry[5]
packed = index_format.pack(*new_entry[:8])
fp.seek(offset)
fp.write(packed)
def _reorder_filelog_parents(repo, fl, to_fix):
"""
Swaps p1 and p2 for all `to_fix` revisions of filelog `fl` and writes the
new version to disk, overwriting the old one with a rename.
"""
from ..pure import parsers # avoid cycle
ui = repo.ui
assert len(to_fix) > 0
rl = fl._revlog
if rl._format_version != constants.REVLOGV1:
msg = "expected version 1 revlog, got version '%d'" % rl._format_version
raise error.ProgrammingError(msg)
index_file = rl._indexfile
new_file_path = index_file + b'.tmp-parents-fix'
repaired_msg = _(b"repaired revision %d of 'filelog %s'\n")
with ui.uninterruptible():
try:
util.copyfile(
rl.opener.join(index_file),
rl.opener.join(new_file_path),
checkambig=rl._checkambig,
)
with rl.opener(new_file_path, mode=b"r+") as fp:
if rl._inline:
index = parsers.InlinedIndexObject(fp.read())
for rev in fl.revs():
if rev in to_fix:
offset = index._calculate_index(rev)
_write_swapped_parents(repo, rl, rev, offset, fp)
ui.write(repaired_msg % (rev, index_file))
else:
index_format = parsers.IndexObject.index_format
for rev in to_fix:
offset = rev * index_format.size
_write_swapped_parents(repo, rl, rev, offset, fp)
ui.write(repaired_msg % (rev, index_file))
rl.opener.rename(new_file_path, index_file)
rl.clearcaches()
rl._loadindex()
finally:
util.tryunlink(new_file_path)
def _is_revision_affected(fl, filerev, metadata_cache=None):
full_text = lambda: fl._revlog.rawdata(filerev)
parent_revs = lambda: fl._revlog.parentrevs(filerev)
return _is_revision_affected_inner(
full_text, parent_revs, filerev, metadata_cache
)
def _is_revision_affected_inner(
full_text,
parents_revs,
filerev,
metadata_cache=None,
):
"""Mercurial currently (5.9rc0) uses `p1 == nullrev and p2 != nullrev` as a
special meaning compared to the reverse in the context of filelog-based
copytracing. issue6528 exists because new code assumed that parent ordering
didn't matter, so this detects if the revision contains metadata (since
it's only used for filelog-based copytracing) and its parents are in the
"wrong" order."""
try:
raw_text = full_text()
except error.CensoredNodeError:
# We don't care about censored nodes as they never carry metadata
return False
has_meta = raw_text.startswith(b'\x01\n')
if metadata_cache is not None:
metadata_cache[filerev] = has_meta
if has_meta:
(p1, p2) = parents_revs()
if p1 != nullrev and p2 == nullrev:
return True
return False
def _is_revision_affected_fast(repo, fl, filerev, metadata_cache):
rl = fl._revlog
is_censored = lambda: rl.iscensored(filerev)
delta_base = lambda: rl.deltaparent(filerev)
delta = lambda: rl._chunk(filerev)
full_text = lambda: rl.rawdata(filerev)
parent_revs = lambda: rl.parentrevs(filerev)
return _is_revision_affected_fast_inner(
is_censored,
delta_base,
delta,
full_text,
parent_revs,
filerev,
metadata_cache,
)
def _is_revision_affected_fast_inner(
is_censored,
delta_base,
delta,
full_text,
parent_revs,
filerev,
metadata_cache,
):
"""Optimization fast-path for `_is_revision_affected`.
`metadata_cache` is a dict of `{rev: has_metadata}` which allows any
revision to check if its base has metadata, saving computation of the full
text, instead looking at the current delta.
This optimization only works if the revisions are looked at in order."""
if is_censored():
# Censored revisions don't contain metadata, so they cannot be affected
metadata_cache[filerev] = False
return False
p1, p2 = parent_revs()
if p1 == nullrev or p2 != nullrev:
return False
delta_parent = delta_base()
parent_has_metadata = metadata_cache.get(delta_parent)
if parent_has_metadata is None:
return _is_revision_affected_inner(
full_text,
parent_revs,
filerev,
metadata_cache,
)
chunk = delta()
if not len(chunk):
# No diff for this revision
return parent_has_metadata
header_length = 12
if len(chunk) < header_length:
raise error.Abort(_(b"patch cannot be decoded"))
start, _end, _length = struct.unpack(b">lll", chunk[:header_length])
if start < 2: # len(b'\x01\n') == 2
# This delta does *something* to the metadata marker (if any).
# Check it the slow way
is_affected = _is_revision_affected_inner(
full_text,
parent_revs,
filerev,
metadata_cache,
)
return is_affected
# The diff did not remove or add the metadata header, it's then in the same
# situation as its parent
metadata_cache[filerev] = parent_has_metadata
return parent_has_metadata
def _from_report(ui, repo, context, from_report, dry_run):
"""
Fix the revisions given in the `from_report` file, but still checks if the
revisions are indeed affected to prevent an unfortunate cyclic situation
where we'd swap well-ordered parents again.
See the doc for `debug_fix_issue6528` for the format documentation.
"""
ui.write(_(b"loading report file '%s'\n") % from_report)
with context(), open(from_report, mode='rb') as f:
for line in f.read().split(b'\n'):
if not line:
continue
filenodes, filename = line.split(b' ', 1)
fl = _filelog_from_filename(repo, filename)
to_fix = set(
fl.rev(binascii.unhexlify(n)) for n in filenodes.split(b',')
)
excluded = set()
for filerev in to_fix:
if _is_revision_affected(fl, filerev):
msg = b"found affected revision %d for filelog '%s'\n"
ui.warn(msg % (filerev, filename))
else:
msg = _(b"revision %s of file '%s' is not affected\n")
msg %= (binascii.hexlify(fl.node(filerev)), filename)
ui.warn(msg)
excluded.add(filerev)
to_fix = to_fix - excluded
if not to_fix:
msg = _(b"no affected revisions were found for '%s'\n")
ui.write(msg % filename)
continue
if not dry_run:
_reorder_filelog_parents(repo, fl, sorted(to_fix))
def repair_issue6528(
ui, repo, dry_run=False, to_report=None, from_report=None, paranoid=False
):
from .. import store # avoid cycle
@contextlib.contextmanager
def context():
if dry_run or to_report: # No need for locking
yield
else:
with repo.wlock(), repo.lock():
yield
if from_report:
return _from_report(ui, repo, context, from_report, dry_run)
report_entries = []
with context():
files = list(
(file_type, path)
for (file_type, path, _e, _s) in repo.store.datafiles()
if path.endswith(b'.i') and file_type & store.FILEFLAGS_FILELOG
)
progress = ui.makeprogress(
_(b"looking for affected revisions"),
unit=_(b"filelogs"),
total=len(files),
)
found_nothing = True
for file_type, path in files:
if (
not path.endswith(b'.i')
or not file_type & store.FILEFLAGS_FILELOG
):
continue
progress.increment()
filename = _get_filename_from_filelog_index(path)
fl = _filelog_from_filename(repo, filename)
# Set of filerevs (or hex filenodes if `to_report`) that need fixing
to_fix = set()
metadata_cache = {}
for filerev in fl.revs():
affected = _is_revision_affected_fast(
repo, fl, filerev, metadata_cache
)
if paranoid:
slow = _is_revision_affected(fl, filerev)
if slow != affected:
msg = _(b"paranoid check failed for '%s' at node %s")
node = binascii.hexlify(fl.node(filerev))
raise error.Abort(msg % (filename, node))
if affected:
msg = b"found affected revision %d for filelog '%s'\n"
ui.warn(msg % (filerev, path))
found_nothing = False
if not dry_run:
if to_report:
to_fix.add(binascii.hexlify(fl.node(filerev)))
else:
to_fix.add(filerev)
if to_fix:
to_fix = sorted(to_fix)
if to_report:
report_entries.append((filename, to_fix))
else:
_reorder_filelog_parents(repo, fl, to_fix)
if found_nothing:
ui.write(_(b"no affected revisions were found\n"))
if to_report and report_entries:
with open(to_report, mode="wb") as f:
for path, to_fix in report_entries:
f.write(b"%s %s\n" % (b",".join(to_fix), path))
progress.complete()