|
|
# storageutil.py - Storage functionality agnostic of backend implementation.
|
|
|
#
|
|
|
# Copyright 2018 Gregory Szorc <gregory.szorc@gmail.com>
|
|
|
#
|
|
|
# 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 re
|
|
|
import struct
|
|
|
|
|
|
from ..i18n import _
|
|
|
from ..node import (
|
|
|
bin,
|
|
|
nullid,
|
|
|
nullrev,
|
|
|
)
|
|
|
from .. import (
|
|
|
dagop,
|
|
|
error,
|
|
|
mdiff,
|
|
|
pycompat,
|
|
|
)
|
|
|
from ..interfaces import repository
|
|
|
from ..utils import hashutil
|
|
|
|
|
|
_nullhash = hashutil.sha1(nullid)
|
|
|
|
|
|
|
|
|
def hashrevisionsha1(text, p1, p2):
|
|
|
"""Compute the SHA-1 for revision data and its parents.
|
|
|
|
|
|
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 = hashutil.sha1(a)
|
|
|
s.update(b)
|
|
|
s.update(text)
|
|
|
return s.digest()
|
|
|
|
|
|
|
|
|
METADATA_RE = re.compile(b'\x01\n')
|
|
|
|
|
|
|
|
|
def parsemeta(text):
|
|
|
"""Parse metadata header from revision data.
|
|
|
|
|
|
Returns a 2-tuple of (metadata, offset), where both can be None if there
|
|
|
is no metadata.
|
|
|
"""
|
|
|
# text can be buffer, so we can't use .startswith or .index
|
|
|
if text[:2] != b'\x01\n':
|
|
|
return None, None
|
|
|
s = METADATA_RE.search(text, 2).start()
|
|
|
mtext = text[2:s]
|
|
|
meta = {}
|
|
|
for l in mtext.splitlines():
|
|
|
k, v = l.split(b': ', 1)
|
|
|
meta[k] = v
|
|
|
return meta, s + 2
|
|
|
|
|
|
|
|
|
def packmeta(meta, text):
|
|
|
"""Add metadata to fulltext to produce revision text."""
|
|
|
keys = sorted(meta)
|
|
|
metatext = b''.join(b'%s: %s\n' % (k, meta[k]) for k in keys)
|
|
|
return b'\x01\n%s\x01\n%s' % (metatext, text)
|
|
|
|
|
|
|
|
|
def iscensoredtext(text):
|
|
|
meta = parsemeta(text)[0]
|
|
|
return meta and b'censored' in meta
|
|
|
|
|
|
|
|
|
def filtermetadata(text):
|
|
|
"""Extract just the revision data from source text.
|
|
|
|
|
|
Returns ``text`` unless it has a metadata header, in which case we return
|
|
|
a new buffer without hte metadata.
|
|
|
"""
|
|
|
if not text.startswith(b'\x01\n'):
|
|
|
return text
|
|
|
|
|
|
offset = text.index(b'\x01\n', 2)
|
|
|
return text[offset + 2 :]
|
|
|
|
|
|
|
|
|
def filerevisioncopied(store, node):
|
|
|
"""Resolve file revision copy metadata.
|
|
|
|
|
|
Returns ``False`` if the file has no copy metadata. Otherwise a
|
|
|
2-tuple of the source filename and node.
|
|
|
"""
|
|
|
if store.parents(node)[0] != nullid:
|
|
|
return False
|
|
|
|
|
|
meta = parsemeta(store.revision(node))[0]
|
|
|
|
|
|
# copy and copyrev occur in pairs. In rare cases due to old bugs,
|
|
|
# one can occur without the other. So ensure both are present to flag
|
|
|
# as a copy.
|
|
|
if meta and b'copy' in meta and b'copyrev' in meta:
|
|
|
return meta[b'copy'], bin(meta[b'copyrev'])
|
|
|
|
|
|
return False
|
|
|
|
|
|
|
|
|
def filedataequivalent(store, node, filedata):
|
|
|
"""Determines whether file data is equivalent to a stored node.
|
|
|
|
|
|
Returns True if the passed file data would hash to the same value
|
|
|
as a stored revision and False otherwise.
|
|
|
|
|
|
When a stored revision is censored, filedata must be empty to have
|
|
|
equivalence.
|
|
|
|
|
|
When a stored revision has copy metadata, it is ignored as part
|
|
|
of the compare.
|
|
|
"""
|
|
|
|
|
|
if filedata.startswith(b'\x01\n'):
|
|
|
revisiontext = b'\x01\n\x01\n' + filedata
|
|
|
else:
|
|
|
revisiontext = filedata
|
|
|
|
|
|
p1, p2 = store.parents(node)
|
|
|
|
|
|
computednode = hashrevisionsha1(revisiontext, p1, p2)
|
|
|
|
|
|
if computednode == node:
|
|
|
return True
|
|
|
|
|
|
# Censored files compare against the empty file.
|
|
|
if store.iscensored(store.rev(node)):
|
|
|
return filedata == b''
|
|
|
|
|
|
# Renaming a file produces a different hash, even if the data
|
|
|
# remains unchanged. Check if that's the case.
|
|
|
if store.renamed(node):
|
|
|
return store.read(node) == filedata
|
|
|
|
|
|
return False
|
|
|
|
|
|
|
|
|
def iterrevs(storelen, start=0, stop=None):
|
|
|
"""Iterate over revision numbers in a store."""
|
|
|
step = 1
|
|
|
|
|
|
if stop is not None:
|
|
|
if start > stop:
|
|
|
step = -1
|
|
|
stop += step
|
|
|
if stop > storelen:
|
|
|
stop = storelen
|
|
|
else:
|
|
|
stop = storelen
|
|
|
|
|
|
return pycompat.xrange(start, stop, step)
|
|
|
|
|
|
|
|
|
def fileidlookup(store, fileid, identifier):
|
|
|
"""Resolve the file node for a value.
|
|
|
|
|
|
``store`` is an object implementing the ``ifileindex`` interface.
|
|
|
|
|
|
``fileid`` can be:
|
|
|
|
|
|
* A 20 byte binary node.
|
|
|
* An integer revision number
|
|
|
* A 40 byte hex node.
|
|
|
* A bytes that can be parsed as an integer representing a revision number.
|
|
|
|
|
|
``identifier`` is used to populate ``error.LookupError`` with an identifier
|
|
|
for the store.
|
|
|
|
|
|
Raises ``error.LookupError`` on failure.
|
|
|
"""
|
|
|
if isinstance(fileid, int):
|
|
|
try:
|
|
|
return store.node(fileid)
|
|
|
except IndexError:
|
|
|
raise error.LookupError(
|
|
|
b'%d' % fileid, identifier, _(b'no match found')
|
|
|
)
|
|
|
|
|
|
if len(fileid) == 20:
|
|
|
try:
|
|
|
store.rev(fileid)
|
|
|
return fileid
|
|
|
except error.LookupError:
|
|
|
pass
|
|
|
|
|
|
if len(fileid) == 40:
|
|
|
try:
|
|
|
rawnode = bin(fileid)
|
|
|
store.rev(rawnode)
|
|
|
return rawnode
|
|
|
except TypeError:
|
|
|
pass
|
|
|
|
|
|
try:
|
|
|
rev = int(fileid)
|
|
|
|
|
|
if b'%d' % rev != fileid:
|
|
|
raise ValueError
|
|
|
|
|
|
try:
|
|
|
return store.node(rev)
|
|
|
except (IndexError, TypeError):
|
|
|
pass
|
|
|
except (ValueError, OverflowError):
|
|
|
pass
|
|
|
|
|
|
raise error.LookupError(fileid, identifier, _(b'no match found'))
|
|
|
|
|
|
|
|
|
def resolvestripinfo(minlinkrev, tiprev, headrevs, linkrevfn, parentrevsfn):
|
|
|
"""Resolve information needed to strip revisions.
|
|
|
|
|
|
Finds the minimum revision number that must be stripped in order to
|
|
|
strip ``minlinkrev``.
|
|
|
|
|
|
Returns a 2-tuple of the minimum revision number to do that and a set
|
|
|
of all revision numbers that have linkrevs that would be broken
|
|
|
by that strip.
|
|
|
|
|
|
``tiprev`` is the current tip-most revision. It is ``len(store) - 1``.
|
|
|
``headrevs`` is an iterable of head revisions.
|
|
|
``linkrevfn`` is a callable that receives a revision and returns a linked
|
|
|
revision.
|
|
|
``parentrevsfn`` is a callable that receives a revision number and returns
|
|
|
an iterable of its parent revision numbers.
|
|
|
"""
|
|
|
brokenrevs = set()
|
|
|
strippoint = tiprev + 1
|
|
|
|
|
|
heads = {}
|
|
|
futurelargelinkrevs = set()
|
|
|
for head in headrevs:
|
|
|
headlinkrev = linkrevfn(head)
|
|
|
heads[head] = headlinkrev
|
|
|
if headlinkrev >= minlinkrev:
|
|
|
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 < minlinkrev:
|
|
|
brokenrevs.add(strippoint)
|
|
|
else:
|
|
|
futurelargelinkrevs.remove(linkrev)
|
|
|
|
|
|
for p in parentrevsfn(strippoint):
|
|
|
if p != nullrev:
|
|
|
plinkrev = linkrevfn(p)
|
|
|
heads[p] = plinkrev
|
|
|
if plinkrev >= minlinkrev:
|
|
|
futurelargelinkrevs.add(plinkrev)
|
|
|
|
|
|
return strippoint, brokenrevs
|
|
|
|
|
|
|
|
|
def emitrevisions(
|
|
|
store,
|
|
|
nodes,
|
|
|
nodesorder,
|
|
|
resultcls,
|
|
|
deltaparentfn=None,
|
|
|
candeltafn=None,
|
|
|
rawsizefn=None,
|
|
|
revdifffn=None,
|
|
|
flagsfn=None,
|
|
|
deltamode=repository.CG_DELTAMODE_STD,
|
|
|
revisiondata=False,
|
|
|
assumehaveparentrevisions=False,
|
|
|
):
|
|
|
"""Generic implementation of ifiledata.emitrevisions().
|
|
|
|
|
|
Emitting revision data is subtly complex. This function attempts to
|
|
|
encapsulate all the logic for doing so in a backend-agnostic way.
|
|
|
|
|
|
``store``
|
|
|
Object conforming to ``ifilestorage`` interface.
|
|
|
|
|
|
``nodes``
|
|
|
List of revision nodes whose data to emit.
|
|
|
|
|
|
``resultcls``
|
|
|
A type implementing the ``irevisiondelta`` interface that will be
|
|
|
constructed and returned.
|
|
|
|
|
|
``deltaparentfn`` (optional)
|
|
|
Callable receiving a revision number and returning the revision number
|
|
|
of a revision that the internal delta is stored against. This delta
|
|
|
will be preferred over computing a new arbitrary delta.
|
|
|
|
|
|
If not defined, a delta will always be computed from raw revision
|
|
|
data.
|
|
|
|
|
|
``candeltafn`` (optional)
|
|
|
Callable receiving a pair of revision numbers that returns a bool
|
|
|
indicating whether a delta between them can be produced.
|
|
|
|
|
|
If not defined, it is assumed that any two revisions can delta with
|
|
|
each other.
|
|
|
|
|
|
``rawsizefn`` (optional)
|
|
|
Callable receiving a revision number and returning the length of the
|
|
|
``store.rawdata(rev)``.
|
|
|
|
|
|
If not defined, ``len(store.rawdata(rev))`` will be called.
|
|
|
|
|
|
``revdifffn`` (optional)
|
|
|
Callable receiving a pair of revision numbers that returns a delta
|
|
|
between them.
|
|
|
|
|
|
If not defined, a delta will be computed by invoking mdiff code
|
|
|
on ``store.revision()`` results.
|
|
|
|
|
|
Defining this function allows a precomputed or stored delta to be
|
|
|
used without having to compute on.
|
|
|
|
|
|
``flagsfn`` (optional)
|
|
|
Callable receiving a revision number and returns the integer flags
|
|
|
value for it. If not defined, flags value will be 0.
|
|
|
|
|
|
``deltamode``
|
|
|
constaint on delta to be sent:
|
|
|
* CG_DELTAMODE_STD - normal mode, try to reuse storage deltas,
|
|
|
* CG_DELTAMODE_PREV - only delta against "prev",
|
|
|
* CG_DELTAMODE_FULL - only issue full snapshot.
|
|
|
|
|
|
Whether to send fulltext revisions instead of deltas, if allowed.
|
|
|
|
|
|
``nodesorder``
|
|
|
``revisiondata``
|
|
|
``assumehaveparentrevisions``
|
|
|
"""
|
|
|
|
|
|
fnode = store.node
|
|
|
frev = store.rev
|
|
|
|
|
|
if nodesorder == b'nodes':
|
|
|
revs = [frev(n) for n in nodes]
|
|
|
elif nodesorder == b'linear':
|
|
|
revs = {frev(n) for n in nodes}
|
|
|
revs = dagop.linearize(revs, store.parentrevs)
|
|
|
else: # storage and default
|
|
|
revs = sorted(frev(n) for n in nodes)
|
|
|
|
|
|
prevrev = None
|
|
|
|
|
|
if deltamode == repository.CG_DELTAMODE_PREV or assumehaveparentrevisions:
|
|
|
prevrev = store.parentrevs(revs[0])[0]
|
|
|
|
|
|
# Set of revs available to delta against.
|
|
|
available = set()
|
|
|
|
|
|
for rev in revs:
|
|
|
if rev == nullrev:
|
|
|
continue
|
|
|
|
|
|
node = fnode(rev)
|
|
|
p1rev, p2rev = store.parentrevs(rev)
|
|
|
|
|
|
if deltaparentfn:
|
|
|
deltaparentrev = deltaparentfn(rev)
|
|
|
else:
|
|
|
deltaparentrev = nullrev
|
|
|
|
|
|
# Forced delta against previous mode.
|
|
|
if deltamode == repository.CG_DELTAMODE_PREV:
|
|
|
baserev = prevrev
|
|
|
|
|
|
# We're instructed to send fulltext. Honor that.
|
|
|
elif deltamode == repository.CG_DELTAMODE_FULL:
|
|
|
baserev = nullrev
|
|
|
# We're instructed to use p1. Honor that
|
|
|
elif deltamode == repository.CG_DELTAMODE_P1:
|
|
|
baserev = p1rev
|
|
|
|
|
|
# There is a delta in storage. We try to use that because it
|
|
|
# amounts to effectively copying data from storage and is
|
|
|
# therefore the fastest.
|
|
|
elif deltaparentrev != nullrev:
|
|
|
# Base revision was already emitted in this group. We can
|
|
|
# always safely use the delta.
|
|
|
if deltaparentrev in available:
|
|
|
baserev = deltaparentrev
|
|
|
|
|
|
# Base revision is a parent that hasn't been emitted already.
|
|
|
# Use it if we can assume the receiver has the parent revision.
|
|
|
elif assumehaveparentrevisions and deltaparentrev in (p1rev, p2rev):
|
|
|
baserev = deltaparentrev
|
|
|
|
|
|
# No guarantee the receiver has the delta parent. Send delta
|
|
|
# against last revision (if possible), which in the common case
|
|
|
# should be similar enough to this revision that the delta is
|
|
|
# reasonable.
|
|
|
elif prevrev is not None:
|
|
|
baserev = prevrev
|
|
|
else:
|
|
|
baserev = nullrev
|
|
|
|
|
|
# Storage has a fulltext revision.
|
|
|
|
|
|
# Let's use the previous revision, which is as good a guess as any.
|
|
|
# There is definitely room to improve this logic.
|
|
|
elif prevrev is not None:
|
|
|
baserev = prevrev
|
|
|
else:
|
|
|
baserev = nullrev
|
|
|
|
|
|
# But we can't actually use our chosen delta base for whatever
|
|
|
# reason. Reset to fulltext.
|
|
|
if baserev != nullrev and (candeltafn and not candeltafn(baserev, rev)):
|
|
|
baserev = nullrev
|
|
|
|
|
|
revision = None
|
|
|
delta = None
|
|
|
baserevisionsize = None
|
|
|
|
|
|
if revisiondata:
|
|
|
if store.iscensored(baserev) or store.iscensored(rev):
|
|
|
try:
|
|
|
revision = store.rawdata(node)
|
|
|
except error.CensoredNodeError as e:
|
|
|
revision = e.tombstone
|
|
|
|
|
|
if baserev != nullrev:
|
|
|
if rawsizefn:
|
|
|
baserevisionsize = rawsizefn(baserev)
|
|
|
else:
|
|
|
baserevisionsize = len(store.rawdata(baserev))
|
|
|
|
|
|
elif (
|
|
|
baserev == nullrev and deltamode != repository.CG_DELTAMODE_PREV
|
|
|
):
|
|
|
revision = store.rawdata(node)
|
|
|
available.add(rev)
|
|
|
else:
|
|
|
if revdifffn:
|
|
|
delta = revdifffn(baserev, rev)
|
|
|
else:
|
|
|
delta = mdiff.textdiff(
|
|
|
store.rawdata(baserev), store.rawdata(rev)
|
|
|
)
|
|
|
|
|
|
available.add(rev)
|
|
|
|
|
|
yield resultcls(
|
|
|
node=node,
|
|
|
p1node=fnode(p1rev),
|
|
|
p2node=fnode(p2rev),
|
|
|
basenode=fnode(baserev),
|
|
|
flags=flagsfn(rev) if flagsfn else 0,
|
|
|
baserevisionsize=baserevisionsize,
|
|
|
revision=revision,
|
|
|
delta=delta,
|
|
|
)
|
|
|
|
|
|
prevrev = rev
|
|
|
|
|
|
|
|
|
def deltaiscensored(delta, baserev, baselenfn):
|
|
|
"""Determine if a delta represents censored revision data.
|
|
|
|
|
|
``baserev`` is the base revision this delta is encoded against.
|
|
|
``baselenfn`` is a callable receiving a revision number that resolves the
|
|
|
length of the revision fulltext.
|
|
|
|
|
|
Returns a bool indicating if the result of the delta represents a censored
|
|
|
revision.
|
|
|
"""
|
|
|
# Fragile heuristic: unless new file meta keys are added alphabetically
|
|
|
# preceding "censored", all censored revisions are prefixed by
|
|
|
# "\1\ncensored:". A delta producing such a censored revision must be a
|
|
|
# full-replacement delta, so we inspect the first and only patch in the
|
|
|
# delta for this prefix.
|
|
|
hlen = struct.calcsize(b">lll")
|
|
|
if len(delta) <= hlen:
|
|
|
return False
|
|
|
|
|
|
oldlen = baselenfn(baserev)
|
|
|
newlen = len(delta) - hlen
|
|
|
if delta[:hlen] != mdiff.replacediffheader(oldlen, newlen):
|
|
|
return False
|
|
|
|
|
|
add = b"\1\ncensored:"
|
|
|
addlen = len(add)
|
|
|
return newlen >= addlen and delta[hlen : hlen + addlen] == add
|
|
|
|
