delta-find: split the _DeltaSearch class in two
We now have things sliced small enough to have two class that use different
`_iter_groups` implementation to encode their different logic.
The filtering code remains to be moved, but I would rather keep this changeset
simple and move them in the next.
# revlogdeltas.py - Logic around delta computation for revlog
#
# Copyright 2005-2007 Olivia Mackall <olivia@selenic.com>
# Copyright 2018 Octobus <contact@octobus.net>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
"""Helper class to compute deltas stored inside revlogs"""
import abc
import collections
import struct
# import stuff from node for others to import from revlog
from ..node import nullrev
from ..i18n import _
from .constants import (
COMP_MODE_DEFAULT,
COMP_MODE_INLINE,
COMP_MODE_PLAIN,
DELTA_BASE_REUSE_FORCE,
DELTA_BASE_REUSE_NO,
KIND_CHANGELOG,
KIND_FILELOG,
KIND_MANIFESTLOG,
REVIDX_ISCENSORED,
REVIDX_RAWTEXT_CHANGING_FLAGS,
)
from ..thirdparty import attr
from .. import (
error,
mdiff,
util,
)
from . import flagutil
# maximum <delta-chain-data>/<revision-text-length> ratio
LIMIT_DELTA2TEXT = 2
class _testrevlog:
"""minimalist fake revlog to use in doctests"""
def __init__(self, data, density=0.5, mingap=0, snapshot=()):
"""data is an list of revision payload boundaries"""
from .. import revlog
self._data = data
self.data_config = revlog.DataConfig()
self.data_config.sr_density_threshold = density
self.data_config.sr_min_gap_size = mingap
self.delta_config = revlog.DeltaConfig()
self.feature_config = revlog.FeatureConfig()
self._snapshot = set(snapshot)
self.index = None
def start(self, rev):
if rev == nullrev:
return 0
if rev == 0:
return 0
return self._data[rev - 1]
def end(self, rev):
if rev == nullrev:
return 0
return self._data[rev]
def length(self, rev):
return self.end(rev) - self.start(rev)
def __len__(self):
return len(self._data)
def issnapshot(self, rev):
if rev == nullrev:
return True
return rev in self._snapshot
def slicechunk(revlog, revs, targetsize=None):
"""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.
The initial chunk is sliced until the overall density (payload/chunks-span
ratio) is above `revlog.data_config.sr_density_threshold`. No gap smaller
than `revlog.data_config.sr_min_gap_size` is skipped.
If `targetsize` is set, no chunk larger than `targetsize` will be yield.
For consistency with other slicing choice, this limit won't go lower than
`revlog.data_config.sr_min_gap_size`.
If individual revisions chunk are larger than this limit, they will still
be raised individually.
>>> data = [
... 5, #00 (5)
... 10, #01 (5)
... 12, #02 (2)
... 12, #03 (empty)
... 27, #04 (15)
... 31, #05 (4)
... 31, #06 (empty)
... 42, #07 (11)
... 47, #08 (5)
... 47, #09 (empty)
... 48, #10 (1)
... 51, #11 (3)
... 74, #12 (23)
... 85, #13 (11)
... 86, #14 (1)
... 91, #15 (5)
... ]
>>> revlog = _testrevlog(data, snapshot=range(16))
>>> list(slicechunk(revlog, list(range(16))))
[[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]]
>>> list(slicechunk(revlog, [0, 15]))
[[0], [15]]
>>> list(slicechunk(revlog, [0, 11, 15]))
[[0], [11], [15]]
>>> list(slicechunk(revlog, [0, 11, 13, 15]))
[[0], [11, 13, 15]]
>>> list(slicechunk(revlog, [1, 2, 3, 5, 8, 10, 11, 14]))
[[1, 2], [5, 8, 10, 11], [14]]
Slicing with a maximum chunk size
>>> list(slicechunk(revlog, [0, 11, 13, 15], targetsize=15))
[[0], [11], [13], [15]]
>>> list(slicechunk(revlog, [0, 11, 13, 15], targetsize=20))
[[0], [11], [13, 15]]
Slicing involving nullrev
>>> list(slicechunk(revlog, [-1, 0, 11, 13, 15], targetsize=20))
[[-1, 0], [11], [13, 15]]
>>> list(slicechunk(revlog, [-1, 13, 15], targetsize=5))
[[-1], [13], [15]]
"""
if targetsize is not None:
targetsize = max(targetsize, revlog.data_config.sr_min_gap_size)
# targetsize should not be specified when evaluating delta candidates:
# * targetsize is used to ensure we stay within specification when reading,
densityslicing = getattr(revlog.index, 'slicechunktodensity', None)
if densityslicing is None:
densityslicing = lambda x, y, z: _slicechunktodensity(revlog, x, y, z)
for chunk in densityslicing(
revs,
revlog.data_config.sr_density_threshold,
revlog.data_config.sr_min_gap_size,
):
for subchunk in _slicechunktosize(revlog, chunk, targetsize):
yield subchunk
def _slicechunktosize(revlog, revs, targetsize=None):
"""slice revs to match the target size
This is intended to be used on chunk that density slicing selected by that
are still too large compared to the read garantee of revlog. This might
happens when "minimal gap size" interrupted the slicing or when chain are
built in a way that create large blocks next to each other.
>>> data = [
... 3, #0 (3)
... 5, #1 (2)
... 6, #2 (1)
... 8, #3 (2)
... 8, #4 (empty)
... 11, #5 (3)
... 12, #6 (1)
... 13, #7 (1)
... 14, #8 (1)
... ]
== All snapshots cases ==
>>> revlog = _testrevlog(data, snapshot=range(9))
Cases where chunk is already small enough
>>> list(_slicechunktosize(revlog, [0], 3))
[[0]]
>>> list(_slicechunktosize(revlog, [6, 7], 3))
[[6, 7]]
>>> list(_slicechunktosize(revlog, [0], None))
[[0]]
>>> list(_slicechunktosize(revlog, [6, 7], None))
[[6, 7]]
cases where we need actual slicing
>>> list(_slicechunktosize(revlog, [0, 1], 3))
[[0], [1]]
>>> list(_slicechunktosize(revlog, [1, 3], 3))
[[1], [3]]
>>> list(_slicechunktosize(revlog, [1, 2, 3], 3))
[[1, 2], [3]]
>>> list(_slicechunktosize(revlog, [3, 5], 3))
[[3], [5]]
>>> list(_slicechunktosize(revlog, [3, 4, 5], 3))
[[3], [5]]
>>> list(_slicechunktosize(revlog, [5, 6, 7, 8], 3))
[[5], [6, 7, 8]]
>>> list(_slicechunktosize(revlog, [0, 1, 2, 3, 4, 5, 6, 7, 8], 3))
[[0], [1, 2], [3], [5], [6, 7, 8]]
Case with too large individual chunk (must return valid chunk)
>>> list(_slicechunktosize(revlog, [0, 1], 2))
[[0], [1]]
>>> list(_slicechunktosize(revlog, [1, 3], 1))
[[1], [3]]
>>> list(_slicechunktosize(revlog, [3, 4, 5], 2))
[[3], [5]]
== No Snapshot cases ==
>>> revlog = _testrevlog(data)
Cases where chunk is already small enough
>>> list(_slicechunktosize(revlog, [0], 3))
[[0]]
>>> list(_slicechunktosize(revlog, [6, 7], 3))
[[6, 7]]
>>> list(_slicechunktosize(revlog, [0], None))
[[0]]
>>> list(_slicechunktosize(revlog, [6, 7], None))
[[6, 7]]
cases where we need actual slicing
>>> list(_slicechunktosize(revlog, [0, 1], 3))
[[0], [1]]
>>> list(_slicechunktosize(revlog, [1, 3], 3))
[[1], [3]]
>>> list(_slicechunktosize(revlog, [1, 2, 3], 3))
[[1], [2, 3]]
>>> list(_slicechunktosize(revlog, [3, 5], 3))
[[3], [5]]
>>> list(_slicechunktosize(revlog, [3, 4, 5], 3))
[[3], [4, 5]]
>>> list(_slicechunktosize(revlog, [5, 6, 7, 8], 3))
[[5], [6, 7, 8]]
>>> list(_slicechunktosize(revlog, [0, 1, 2, 3, 4, 5, 6, 7, 8], 3))
[[0], [1, 2], [3], [5], [6, 7, 8]]
Case with too large individual chunk (must return valid chunk)
>>> list(_slicechunktosize(revlog, [0, 1], 2))
[[0], [1]]
>>> list(_slicechunktosize(revlog, [1, 3], 1))
[[1], [3]]
>>> list(_slicechunktosize(revlog, [3, 4, 5], 2))
[[3], [5]]
== mixed case ==
>>> revlog = _testrevlog(data, snapshot=[0, 1, 2])
>>> list(_slicechunktosize(revlog, list(range(9)), 5))
[[0, 1], [2], [3, 4, 5], [6, 7, 8]]
"""
assert targetsize is None or 0 <= targetsize
startdata = revlog.start(revs[0])
enddata = revlog.end(revs[-1])
fullspan = enddata - startdata
if targetsize is None or fullspan <= targetsize:
yield revs
return
startrevidx = 0
endrevidx = 1
iterrevs = enumerate(revs)
next(iterrevs) # skip first rev.
# first step: get snapshots out of the way
for idx, r in iterrevs:
span = revlog.end(r) - startdata
snapshot = revlog.issnapshot(r)
if span <= targetsize and snapshot:
endrevidx = idx + 1
else:
chunk = _trimchunk(revlog, revs, startrevidx, endrevidx)
if chunk:
yield chunk
startrevidx = idx
startdata = revlog.start(r)
endrevidx = idx + 1
if not snapshot:
break
# for the others, we use binary slicing to quickly converge toward valid
# chunks (otherwise, we might end up looking for start/end of many
# revisions). This logic is not looking for the perfect slicing point, it
# focuses on quickly converging toward valid chunks.
nbitem = len(revs)
while (enddata - startdata) > targetsize:
endrevidx = nbitem
if nbitem - startrevidx <= 1:
break # protect against individual chunk larger than limit
localenddata = revlog.end(revs[endrevidx - 1])
span = localenddata - startdata
while span > targetsize:
if endrevidx - startrevidx <= 1:
break # protect against individual chunk larger than limit
endrevidx -= (endrevidx - startrevidx) // 2
localenddata = revlog.end(revs[endrevidx - 1])
span = localenddata - startdata
chunk = _trimchunk(revlog, revs, startrevidx, endrevidx)
if chunk:
yield chunk
startrevidx = endrevidx
startdata = revlog.start(revs[startrevidx])
chunk = _trimchunk(revlog, revs, startrevidx)
if chunk:
yield chunk
def _slicechunktodensity(revlog, revs, targetdensity=0.5, mingapsize=0):
"""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.
The initial chunk is sliced until the overall density (payload/chunks-span
ratio) is above `targetdensity`. No gap smaller than `mingapsize` is
skipped.
>>> revlog = _testrevlog([
... 5, #00 (5)
... 10, #01 (5)
... 12, #02 (2)
... 12, #03 (empty)
... 27, #04 (15)
... 31, #05 (4)
... 31, #06 (empty)
... 42, #07 (11)
... 47, #08 (5)
... 47, #09 (empty)
... 48, #10 (1)
... 51, #11 (3)
... 74, #12 (23)
... 85, #13 (11)
... 86, #14 (1)
... 91, #15 (5)
... ])
>>> list(_slicechunktodensity(revlog, list(range(16))))
[[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]]
>>> list(_slicechunktodensity(revlog, [0, 15]))
[[0], [15]]
>>> list(_slicechunktodensity(revlog, [0, 11, 15]))
[[0], [11], [15]]
>>> list(_slicechunktodensity(revlog, [0, 11, 13, 15]))
[[0], [11, 13, 15]]
>>> list(_slicechunktodensity(revlog, [1, 2, 3, 5, 8, 10, 11, 14]))
[[1, 2], [5, 8, 10, 11], [14]]
>>> list(_slicechunktodensity(revlog, [1, 2, 3, 5, 8, 10, 11, 14],
... mingapsize=20))
[[1, 2, 3, 5, 8, 10, 11], [14]]
>>> list(_slicechunktodensity(revlog, [1, 2, 3, 5, 8, 10, 11, 14],
... targetdensity=0.95))
[[1, 2], [5], [8, 10, 11], [14]]
>>> list(_slicechunktodensity(revlog, [1, 2, 3, 5, 8, 10, 11, 14],
... targetdensity=0.95, mingapsize=12))
[[1, 2], [5, 8, 10, 11], [14]]
"""
start = revlog.start
length = revlog.length
if len(revs) <= 1:
yield revs
return
deltachainspan = segmentspan(revlog, revs)
if deltachainspan < mingapsize:
yield revs
return
readdata = deltachainspan
chainpayload = sum(length(r) for r in revs)
if deltachainspan:
density = chainpayload / float(deltachainspan)
else:
density = 1.0
if density >= targetdensity:
yield revs
return
# Store the gaps in a heap to have them sorted by decreasing size
gaps = []
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 > mingapsize:
gaps.append((gapsize, i))
prevend = revstart + revlen
# sort the gaps to pop them from largest to small
gaps.sort()
# Collect the indices of the largest holes until the density is acceptable
selected = []
while gaps and density < targetdensity:
gapsize, gapidx = gaps.pop()
selected.append(gapidx)
# the gap sizes are stored as negatives to be sorted decreasingly
# by the heap
readdata -= gapsize
if readdata > 0:
density = chainpayload / float(readdata)
else:
density = 1.0
selected.sort()
# Cut the revs at collected indices
previdx = 0
for idx in selected:
chunk = _trimchunk(revlog, revs, previdx, idx)
if chunk:
yield chunk
previdx = idx
chunk = _trimchunk(revlog, revs, previdx)
if chunk:
yield chunk
def _trimchunk(revlog, revs, startidx, endidx=None):
"""returns revs[startidx:endidx] without empty trailing revs
Doctest Setup
>>> revlog = _testrevlog([
... 5, #0
... 10, #1
... 12, #2
... 12, #3 (empty)
... 17, #4
... 21, #5
... 21, #6 (empty)
... ])
Contiguous cases:
>>> _trimchunk(revlog, [0, 1, 2, 3, 4, 5, 6], 0)
[0, 1, 2, 3, 4, 5]
>>> _trimchunk(revlog, [0, 1, 2, 3, 4, 5, 6], 0, 5)
[0, 1, 2, 3, 4]
>>> _trimchunk(revlog, [0, 1, 2, 3, 4, 5, 6], 0, 4)
[0, 1, 2]
>>> _trimchunk(revlog, [0, 1, 2, 3, 4, 5, 6], 2, 4)
[2]
>>> _trimchunk(revlog, [0, 1, 2, 3, 4, 5, 6], 3)
[3, 4, 5]
>>> _trimchunk(revlog, [0, 1, 2, 3, 4, 5, 6], 3, 5)
[3, 4]
Discontiguous cases:
>>> _trimchunk(revlog, [1, 3, 5, 6], 0)
[1, 3, 5]
>>> _trimchunk(revlog, [1, 3, 5, 6], 0, 2)
[1]
>>> _trimchunk(revlog, [1, 3, 5, 6], 1, 3)
[3, 5]
>>> _trimchunk(revlog, [1, 3, 5, 6], 1)
[3, 5]
"""
length = revlog.length
if endidx is None:
endidx = len(revs)
# If we have a non-emtpy delta candidate, there are nothing to trim
if revs[endidx - 1] < len(revlog):
# Trim empty revs at the end, except 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 segmentspan(revlog, revs):
"""Get the byte span of a segment of revisions
revs is a sorted array of revision numbers
>>> revlog = _testrevlog([
... 5, #0
... 10, #1
... 12, #2
... 12, #3 (empty)
... 17, #4
... ])
>>> segmentspan(revlog, [0, 1, 2, 3, 4])
17
>>> segmentspan(revlog, [0, 4])
17
>>> segmentspan(revlog, [3, 4])
5
>>> segmentspan(revlog, [1, 2, 3,])
7
>>> segmentspan(revlog, [1, 3])
7
"""
if not revs:
return 0
end = revlog.end(revs[-1])
return end - revlog.start(revs[0])
def _textfromdelta(revlog, baserev, delta, p1, p2, flags, expectednode):
"""build full text from a (base, delta) pair and other metadata"""
# 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(b">lll")
if delta[:hlen] == mdiff.replacediffheader(
revlog.rawsize(baserev), len(delta) - hlen
):
fulltext = delta[hlen:]
else:
# deltabase is rawtext before changed by flag processors, which is
# equivalent to non-raw text
basetext = revlog.revision(baserev)
fulltext = mdiff.patch(basetext, delta)
try:
validatehash = flagutil.processflagsraw(revlog, fulltext, flags)
if validatehash:
revlog.checkhash(fulltext, expectednode, p1=p1, p2=p2)
if flags & REVIDX_ISCENSORED:
raise error.StorageError(
_(b'node %s is not censored') % expectednode
)
except error.CensoredNodeError:
# must pass the censored index flag to add censored revisions
if not flags & REVIDX_ISCENSORED:
raise
return fulltext
@attr.s(slots=True, frozen=True)
class _deltainfo:
distance = attr.ib()
deltalen = attr.ib()
data = attr.ib()
base = attr.ib()
chainbase = attr.ib()
chainlen = attr.ib()
compresseddeltalen = attr.ib()
snapshotdepth = attr.ib()
def drop_u_compression(delta):
"""turn into a "u" (no-compression) into no-compression without header
This is useful for revlog format that has better compression method.
"""
assert delta.data[0] == b'u', delta.data[0]
return _deltainfo(
delta.distance,
delta.deltalen - 1,
(b'', delta.data[1]),
delta.base,
delta.chainbase,
delta.chainlen,
delta.compresseddeltalen,
delta.snapshotdepth,
)
# If a revision's full text is that much bigger than a base candidate full
# text's, it is very unlikely that it will produce a valid delta. We no longer
# consider these candidates.
LIMIT_BASE2TEXT = 500
### stage of the search, used for debug and to select and to adjust some logic.
# initial stage, next step is unknown
_STAGE_UNSPECIFIED = "unspecified"
# trying the cached delta
_STAGE_CACHED = "cached"
# trying delta based on parents
_STAGE_PARENTS = "parents"
# trying to build a valid snapshot of any level
_STAGE_SNAPSHOT = "snapshot"
# trying to build a delta based of the previous revision
_STAGE_PREV = "prev"
# trying to build a full snapshot
_STAGE_FULL = "full"
class _BaseDeltaSearch(abc.ABC):
"""perform the search of a good delta for a single revlog revision
note: some of the deltacomputer.finddeltainfo logic should probably move
here.
"""
def __init__(
self,
revlog,
revinfo,
p1,
p2,
cachedelta,
excluded_bases=None,
target_rev=None,
snapshot_cache=None,
):
# the DELTA_BASE_REUSE_FORCE case should have been taken care of sooner
# so we should never end up asking such question. Adding the assert as
# a safe-guard to detect anything that would be fishy in this regard.
assert (
cachedelta is None
or cachedelta[2] != DELTA_BASE_REUSE_FORCE
or not revlog.delta_config.general_delta
)
self.revlog = revlog
self.revinfo = revinfo
self.textlen = revinfo.textlen
self.p1 = p1
self.p2 = p2
self.cachedelta = cachedelta
self.excluded_bases = excluded_bases
if target_rev is None:
self.target_rev = len(self.revlog)
self.target_rev = target_rev
if snapshot_cache is None:
# map: base-rev: [snapshot-revs]
snapshot_cache = SnapshotCache()
self.snapshot_cache = snapshot_cache
self.tested = {nullrev}
self.current_stage = _STAGE_UNSPECIFIED
self.current_group = None
self._init_group()
def is_good_delta_info(self, deltainfo):
"""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 not self._is_good_delta_info_universal(deltainfo):
return False
if not self._is_good_delta_info_chain_quality(deltainfo):
return False
if not self._is_good_delta_info_snapshot_constraints(deltainfo):
return False
return True
def _is_good_delta_info_universal(self, deltainfo):
"""Returns True if the given delta is good.
This performs generic checks needed by all format variants.
This is used by is_good_delta_info.
"""
if deltainfo is None:
return False
# the DELTA_BASE_REUSE_FORCE case should have been taken care of sooner
# so we should never end up asking such question. Adding the assert as
# a safe-guard to detect anything that would be fishy in this regard.
assert (
self.revinfo.cachedelta is None
or self.revinfo.cachedelta[2] != DELTA_BASE_REUSE_FORCE
or not self.revlog.delta_config.general_delta
)
# Bad delta from new delta size:
#
# If the delta size is larger than the target text, storing the delta
# will be inefficient.
if self.revinfo.textlen < deltainfo.deltalen:
return False
return True
def _is_good_delta_info_chain_quality(self, deltainfo):
"""Returns True if the chain associated with the delta is good.
This performs checks for format that use delta chains.
This is used by is_good_delta_info.
"""
# - 'deltainfo.distance' is the distance from the base revision --
# bounding it limits the amount of I/O we need to do.
defaultmax = self.revinfo.textlen * 4
maxdist = self.revlog.delta_config.max_deltachain_span
if not maxdist:
maxdist = deltainfo.distance # ensure the conditional pass
maxdist = max(maxdist, defaultmax)
# Bad delta from read span:
#
# If the span of data read is larger than the maximum allowed.
#
# In the sparse-revlog case, we rely on the associated "sparse
# reading" to avoid issue related to the span of data. In theory, it
# would be possible to build pathological revlog where delta pattern
# would lead to too many reads. However, they do not happen in
# practice at all. So we skip the span check entirely.
if (
not self.revlog.delta_config.sparse_revlog
and maxdist < deltainfo.distance
):
return False
# Bad delta from cumulated payload size:
#
# - 'deltainfo.compresseddeltalen' is the sum of the total size of
# deltas we need to apply -- bounding it limits the amount of CPU
# we consume.
max_chain_data = self.revinfo.textlen * LIMIT_DELTA2TEXT
# If the sum of delta get larger than K * target text length.
if max_chain_data < deltainfo.compresseddeltalen:
return False
# Bad delta from chain length:
#
# If the number of delta in the chain gets too high.
if (
self.revlog.delta_config.max_chain_len
and self.revlog.delta_config.max_chain_len < deltainfo.chainlen
):
return False
return True
def _is_good_delta_info_snapshot_constraints(self, deltainfo):
"""Returns True if the chain associated with snapshots
This performs checks for format that use sparse-revlog and intermediate
snapshots.
This is used by is_good_delta_info.
"""
# if not a snapshot, this method has no filtering to do
if deltainfo.snapshotdepth is None:
return True
# bad delta from intermediate snapshot size limit
#
# If an intermediate snapshot size is higher than the limit. The
# limit exist to prevent endless chain of intermediate delta to be
# created.
if (
self.revinfo.textlen >> deltainfo.snapshotdepth
) < deltainfo.deltalen:
return False
# bad delta if new intermediate snapshot is larger than the previous
# snapshot
if self.revlog.length(deltainfo.base) < deltainfo.deltalen:
return False
return True
@property
def done(self):
"""True when all possible candidate have been tested"""
return self.current_group is None
@abc.abstractmethod
def next_group(self, good_delta=None):
"""move to the next group to test
The group of revision to test will be available in
`self.current_group`. If the previous group had any good delta, the
best one can be passed as the `good_delta` parameter to help selecting
the next group.
If not revision remains to be, `self.done` will be True and
`self.current_group` will be None.
"""
pass
@abc.abstractmethod
def _init_group(self):
pass
class _NoDeltaSearch(_BaseDeltaSearch):
"""Search for no delta.
This search variant is to be used in case where we should not store delta.
"""
def _init_group(self):
self.current_stage = _STAGE_FULL
def next_group(self, good_delta=None):
pass
class _PrevDeltaSearch(_BaseDeltaSearch):
"""Search for delta against the previous revision only
This search variant is to be used when the format does not allow for delta
against arbitrary bases.
"""
def _init_group(self):
self.current_stage = _STAGE_PREV
self.current_group = [self.target_rev - 1]
self.tested.update(self.current_group)
def next_group(self, good_delta=None):
self.current_stage = _STAGE_FULL
self.current_group = None
class _GeneralDeltaSearch(_BaseDeltaSearch):
"""Delta search variant for general-delta repository"""
def _init_group(self):
# Why search for delta base if we cannot use a delta base ?
# also see issue6056
assert self.revlog.delta_config.general_delta
self._candidates_iterator = self._iter_groups()
self._last_good = None
if (
self.cachedelta is not None
and self.cachedelta[2] > DELTA_BASE_REUSE_NO
and self._pre_filter_rev(self.cachedelta[0])
):
# First we try to reuse a the delta contained in the bundle. (or from
# the source revlog)
#
# This logic only applies to general delta repositories and can be
# disabled through configuration. Disabling reuse source delta is
# useful when we want to make sure we recomputed "optimal" deltas.
self.current_stage = _STAGE_CACHED
self._internal_group = (self.cachedelta[0],)
self._internal_idx = 0
self.current_group = self._internal_group
self.tested.update(self.current_group)
else:
self._next_internal_group()
def _next_internal_group(self):
# self._internal_group can be larger than self.current_group
self._internal_idx = 0
group = self._candidates_iterator.send(self._last_good)
if group is not None:
group = self._pre_filter_candidate_revs(group)
self._internal_group = group
if self._internal_group is None:
self.current_group = None
elif len(self._internal_group) == 0:
self.next_group()
else:
chunk_size = self.revlog.delta_config.candidate_group_chunk_size
if chunk_size > 0:
self.current_group = self._internal_group[:chunk_size]
self._internal_idx += chunk_size
else:
self.current_group = self._internal_group
self._internal_idx += len(self.current_group)
self.tested.update(self.current_group)
def next_group(self, good_delta=None):
old_good = self._last_good
if good_delta is not None:
self._last_good = good_delta.base
if self.current_stage == _STAGE_CACHED and good_delta is not None:
# the cache is good, let us use the cache as requested
self._candidates_iterator = None
self._internal_group = None
self._internal_idx = None
self.current_group = None
return
if (self._internal_idx < len(self._internal_group)) and (
old_good != good_delta
):
# When the size of the candidate group is big, it can result in
# a quite significant performance impact. To reduce this, we
# can send them in smaller batches until the new batch does not
# provide any improvements.
#
# This might reduce the overall efficiency of the compression
# in some corner cases, but that should also prevent very
# pathological cases from being an issue. (eg. 20 000
# candidates).
#
# XXX note that the ordering of the group becomes important as
# it now impacts the final result. The current order is
# unprocessed and can be improved.
next_idx = self._internal_idx + self._group_chunk_size
self.current_group = self._internal_group[
self._internal_idx : next_idx
]
self.tested.update(self.current_group)
self._internal_idx = next_idx
else:
self._next_internal_group()
def _pre_filter_candidate_revs(self, temptative):
"""filter possible candidate before computing a delta
This function use various criteria to pre-filter candidate delta base
before we compute a delta and evaluate its quality.
Such pre-filter limit the number of computed delta, an expensive operation.
return the updated list of revision to test
"""
deltalength = self.revlog.length
deltaparent = self.revlog.deltaparent
tested = self.tested
group = []
for rev in temptative:
# skip over empty delta (no need to include them in a chain)
while not (rev == nullrev or rev in tested or deltalength(rev)):
tested.add(rev)
rev = deltaparent(rev)
if self._pre_filter_rev(rev):
group.append(rev)
else:
self.tested.add(rev)
return group
def _pre_filter_rev_universal(self, rev):
"""pre filtering that is need in all cases.
return True if it seems okay to test a rev, False otherwise.
used by _pre_filter_rev.
"""
# no need to try a delta against nullrev, this will be done as
# a last resort.
if rev == nullrev:
return False
# filter out revision we tested already
if rev in self.tested:
return False
# an higher authority deamed the base unworthy (e.g. censored)
if self.excluded_bases is not None and rev in self.excluded_bases:
return False
# We are in some recomputation cases and that rev is too high
# in the revlog
if self.target_rev is not None and rev >= self.target_rev:
return False
# no delta for rawtext-changing revs (see "candelta" for why)
if self.revlog.flags(rev) & REVIDX_RAWTEXT_CHANGING_FLAGS:
return False
return True
def _pre_filter_rev_sparse(self, rev):
"""pre filtering that is needed in sparse revlog cases
return True if it seems okay to test a rev, False otherwise.
used by _pre_filter_rev.
"""
assert self.revlog.delta_config.sparse_revlog
# if the revision we test again is too small, the resulting delta
# will be large anyway as that amount of data to be added is big
if self.revlog.rawsize(rev) < (self.textlen // LIMIT_BASE2TEXT):
return False
if self.revlog.delta_config.upper_bound_comp is not None:
maxcomp = self.revlog.delta_config.upper_bound_comp
basenotsnap = (self.p1, self.p2, nullrev)
if rev not in basenotsnap and self.revlog.issnapshot(rev):
snapshotdepth = self.revlog.snapshotdepth(rev)
# If text is significantly larger than the base, we can
# expect the resulting delta to be proportional to the size
# difference
revsize = self.revlog.rawsize(rev)
rawsizedistance = max(self.textlen - revsize, 0)
# use an estimate of the compression upper bound.
lowestrealisticdeltalen = rawsizedistance // maxcomp
# check the absolute constraint on the delta size
snapshotlimit = self.textlen >> snapshotdepth
if snapshotlimit < lowestrealisticdeltalen:
# delta lower bound is larger than accepted upper
# bound
return False
# check the relative constraint on the delta size
revlength = self.revlog.length(rev)
if revlength < lowestrealisticdeltalen:
# delta probable lower bound is larger than target
# base
return False
return True
def _pre_filter_rev_delta_chain(self, rev):
"""pre filtering that is needed in sparse revlog cases
return True if it seems okay to test a rev, False otherwise.
used by _pre_filter_rev.
"""
deltas_limit = self.revinfo.textlen * LIMIT_DELTA2TEXT
# filter out delta base that will never produce good delta
#
# if the delta of that base is already bigger than the limit
# for the delta chain size, doing a delta is hopeless.
if deltas_limit < self.revlog.length(rev):
return False
# If we reach here, we are about to build and test a delta.
# The delta building process will compute the chaininfo in all
# case, since that computation is cached, it is fine to access
# it here too.
chainlen, chainsize = self.revlog._chaininfo(rev)
# if chain will be too long, skip base
if (
self.revlog.delta_config.max_chain_len
and chainlen >= self.revlog.delta_config.max_chain_len
):
return False
# if chain already have too much data, skip base
if deltas_limit < chainsize:
return False
return True
def _pre_filter_rev(self, rev):
"""return True if it seems okay to test a rev, False otherwise"""
if not self._pre_filter_rev_universal(rev):
return False
if not self._pre_filter_rev_delta_chain(rev):
return False
if self.revlog.delta_config.sparse_revlog:
if not self._pre_filter_rev_sparse(rev):
return False
return True
def _iter_parents(self):
# exclude already lazy tested base if any
parents = [p for p in (self.p1, self.p2) if p != nullrev]
self.current_stage = _STAGE_PARENTS
if (
not self.revlog.delta_config.delta_both_parents
and len(parents) == 2
):
parents.sort()
# To minimize the chance of having to build a fulltext,
# pick first whichever parent is closest to us (max rev)
yield (parents[1],)
# then the other one (min rev) if the first did not fit
yield (parents[0],)
elif len(parents) > 0:
# Test all parents (1 or 2), and keep the best candidate
yield parents
def _iter_prev(self):
# other approach failed try against prev to hopefully save us a
# fulltext.
self.current_stage = _STAGE_PREV
yield (self.target_rev - 1,)
def _iter_groups(self):
good = None
for group in self._iter_parents():
good = yield group
if good is not None:
break
else:
assert good is None
yield from self._iter_prev()
yield None
class _SparseDeltaSearch(_GeneralDeltaSearch):
"""Delta search variants for sparse-revlog"""
def _iter_snapshots_base(self):
assert self.revlog.delta_config.sparse_revlog
assert self.current_stage == _STAGE_SNAPSHOT
prev = self.target_rev - 1
deltachain = lambda rev: self.revlog._deltachain(rev)[0]
parents = [p for p in (self.p1, self.p2) if p != nullrev]
if not parents:
return
# See if we can use an existing snapshot in the parent chains to
# use as a base for a new intermediate-snapshot
#
# search for snapshot in parents delta chain map: snapshot-level:
# snapshot-rev
parents_snaps = collections.defaultdict(set)
candidate_chains = [deltachain(p) for p in parents]
for chain in candidate_chains:
for idx, s in enumerate(chain):
if not self.revlog.issnapshot(s):
break
parents_snaps[idx].add(s)
snapfloor = min(parents_snaps[0]) + 1
self.snapshot_cache.update(self.revlog, snapfloor)
# search for the highest "unrelated" revision
#
# Adding snapshots used by "unrelated" revision increase the odd we
# reuse an independant, yet better snapshot chain.
#
# XXX instead of building a set of revisions, we could lazily
# enumerate over the chains. That would be more efficient, however
# we stick to simple code for now.
all_revs = set()
for chain in candidate_chains:
all_revs.update(chain)
other = None
for r in self.revlog.revs(prev, snapfloor):
if r not in all_revs:
other = r
break
if other is not None:
# To avoid unfair competition, we won't use unrelated
# intermediate snapshot that are deeper than the ones from the
# parent delta chain.
max_depth = max(parents_snaps.keys())
chain = deltachain(other)
for depth, s in enumerate(chain):
if s < snapfloor:
continue
if max_depth < depth:
break
if not self.revlog.issnapshot(s):
break
parents_snaps[depth].add(s)
# Test them as possible intermediate snapshot base We test them
# from highest to lowest level. High level one are more likely to
# result in small delta
floor = None
for idx, snaps in sorted(parents_snaps.items(), reverse=True):
siblings = set()
for s in snaps:
siblings.update(self.snapshot_cache.snapshots[s])
# Before considering making a new intermediate snapshot, we
# check if an existing snapshot, children of base we consider,
# would be suitable.
#
# It give a change to reuse a delta chain "unrelated" to the
# current revision instead of starting our own. Without such
# re-use, topological branches would keep reopening new chains.
# Creating more and more snapshot as the repository grow.
if floor is not None:
# We only do this for siblings created after the one in our
# parent's delta chain. Those created before has less
# chances to be valid base since our ancestors had to
# create a new snapshot.
siblings = [r for r in siblings if floor < r]
yield tuple(sorted(siblings))
# then test the base from our parent's delta chain.
yield tuple(sorted(snaps))
floor = min(snaps)
# No suitable base found in the parent chain, search if any full
# snapshots emitted since parent's base would be a suitable base
# for an intermediate snapshot.
#
# It give a chance to reuse a delta chain unrelated to the current
# revisions instead of starting our own. Without such re-use,
# topological branches would keep reopening new full chains.
# Creating more and more snapshot as the repository grow.
full = [
r for r in self.snapshot_cache.snapshots[nullrev] if snapfloor <= r
]
yield tuple(sorted(full))
def _iter_snapshots(self):
assert self.revlog.delta_config.sparse_revlog
self.current_stage = _STAGE_SNAPSHOT
good = None
groups = self._iter_snapshots_base()
for candidates in groups:
good = yield candidates
if good is not None:
break
# if we have a refinable value, try to refine it
if (
good is not None
and good not in (self.p1, self.p2)
and self.revlog.issnapshot(good)
):
assert self.current_stage == _STAGE_SNAPSHOT
# refine snapshot down
previous = None
while previous != good:
previous = good
base = self.revlog.deltaparent(good)
if base == nullrev:
break
good = yield (base,)
# refine snapshot up
if not self.snapshot_cache.snapshots:
self.snapshot_cache.update(self.revlog, good + 1)
previous = None
while good != previous:
previous = good
children = tuple(
sorted(c for c in self.snapshot_cache.snapshots[good])
)
good = yield children
yield None
def _iter_groups(self):
good = None
for group in self._iter_parents():
good = yield group
if good is not None:
break
else:
assert good is None
assert self.revlog.delta_config.sparse_revlog
# If sparse revlog is enabled, we can try to refine the
# available deltas
iter_snap = self._iter_snapshots()
group = iter_snap.send(None)
while group is not None:
good = yield group
group = iter_snap.send(good)
yield None
class SnapshotCache:
__slots__ = ('snapshots', '_start_rev', '_end_rev')
def __init__(self):
self.snapshots = collections.defaultdict(set)
self._start_rev = None
self._end_rev = None
def update(self, revlog, start_rev=0):
"""find snapshots from start_rev to tip"""
nb_revs = len(revlog)
end_rev = nb_revs - 1
if start_rev > end_rev:
return # range is empty
if self._start_rev is None:
assert self._end_rev is None
self._update(revlog, start_rev, end_rev)
elif not (self._start_rev <= start_rev and end_rev <= self._end_rev):
if start_rev < self._start_rev:
self._update(revlog, start_rev, self._start_rev - 1)
if self._end_rev < end_rev:
self._update(revlog, self._end_rev + 1, end_rev)
if self._start_rev is None:
assert self._end_rev is None
self._end_rev = end_rev
self._start_rev = start_rev
else:
self._start_rev = min(self._start_rev, start_rev)
self._end_rev = max(self._end_rev, end_rev)
assert self._start_rev <= self._end_rev, (
self._start_rev,
self._end_rev,
)
def _update(self, revlog, start_rev, end_rev):
"""internal method that actually do update content"""
assert self._start_rev is None or (
start_rev < self._start_rev or start_rev > self._end_rev
), (self._start_rev, self._end_rev, start_rev, end_rev)
assert self._start_rev is None or (
end_rev < self._start_rev or end_rev > self._end_rev
), (self._start_rev, self._end_rev, start_rev, end_rev)
cache = self.snapshots
if hasattr(revlog.index, 'findsnapshots'):
revlog.index.findsnapshots(cache, start_rev, end_rev)
else:
deltaparent = revlog.deltaparent
issnapshot = revlog.issnapshot
for rev in revlog.revs(start_rev, end_rev):
if issnapshot(rev):
cache[deltaparent(rev)].add(rev)
class deltacomputer:
"""object capable of computing delta and finding delta for multiple revision
This object is meant to compute and find multiple delta applied to the same
revlog.
"""
def __init__(
self,
revlog,
write_debug=None,
debug_search=False,
debug_info=None,
):
self.revlog = revlog
self._write_debug = write_debug
if write_debug is None:
self._debug_search = False
else:
self._debug_search = debug_search
self._debug_info = debug_info
self._snapshot_cache = SnapshotCache()
@property
def _gather_debug(self):
return self._write_debug is not None or self._debug_info is not None
def buildtext(self, revinfo):
"""Builds a fulltext version of a revision
revinfo: revisioninfo instance that contains all needed info
"""
btext = revinfo.btext
if btext[0] is not None:
return btext[0]
revlog = self.revlog
cachedelta = revinfo.cachedelta
baserev = cachedelta[0]
delta = cachedelta[1]
fulltext = btext[0] = _textfromdelta(
revlog,
baserev,
delta,
revinfo.p1,
revinfo.p2,
revinfo.flags,
revinfo.node,
)
return fulltext
def _builddeltadiff(self, base, revinfo):
revlog = self.revlog
t = self.buildtext(revinfo)
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.rawdata(base)
delta = mdiff.textdiff(ptext, t)
return delta
def _builddeltainfo(
self, revinfo, base, target_rev=None, as_snapshot=False
):
# can we use the cached delta?
revlog = self.revlog
chainbase = revlog.chainbase(base)
if revlog.delta_config.general_delta:
deltabase = base
else:
if target_rev is not None and base != target_rev - 1:
msg = (
b'general delta cannot use delta for something else '
b'than `prev`: %d<-%d'
)
msg %= (base, target_rev)
raise error.ProgrammingError(msg)
deltabase = chainbase
snapshotdepth = None
if revlog.delta_config.sparse_revlog and deltabase == nullrev:
snapshotdepth = 0
elif revlog.delta_config.sparse_revlog and as_snapshot:
assert revlog.issnapshot(deltabase)
# A delta chain should always be one full snapshot,
# zero or more semi-snapshots, and zero or more deltas
p1, p2 = revlog.rev(revinfo.p1), revlog.rev(revinfo.p2)
if deltabase not in (p1, p2) and revlog.issnapshot(deltabase):
snapshotdepth = len(revlog._deltachain(deltabase)[0])
delta = None
if revinfo.cachedelta:
cachebase = revinfo.cachedelta[0]
# check if the diff still apply
currentbase = cachebase
while (
currentbase != nullrev
and currentbase != base
and self.revlog.length(currentbase) == 0
):
currentbase = self.revlog.deltaparent(currentbase)
if self.revlog.delta_config.lazy_delta and currentbase == base:
delta = revinfo.cachedelta[1]
if delta is None:
delta = self._builddeltadiff(base, revinfo)
if self._debug_search:
msg = b"DBG-DELTAS-SEARCH: uncompressed-delta-size=%d\n"
msg %= len(delta)
self._write_debug(msg)
# snapshotdept need to be neither None nor 0 level snapshot
if revlog.delta_config.upper_bound_comp is not None and snapshotdepth:
lowestrealisticdeltalen = (
len(delta) // revlog.delta_config.upper_bound_comp
)
snapshotlimit = revinfo.textlen >> snapshotdepth
if self._debug_search:
msg = b"DBG-DELTAS-SEARCH: projected-lower-size=%d\n"
msg %= lowestrealisticdeltalen
self._write_debug(msg)
if snapshotlimit < lowestrealisticdeltalen:
if self._debug_search:
msg = b"DBG-DELTAS-SEARCH: DISCARDED (snapshot limit)\n"
self._write_debug(msg)
return None
if revlog.length(base) < lowestrealisticdeltalen:
if self._debug_search:
msg = b"DBG-DELTAS-SEARCH: DISCARDED (prev size)\n"
self._write_debug(msg)
return None
header, data = revlog._inner.compress(delta)
deltalen = len(header) + len(data)
offset = revlog.end(len(revlog) - 1)
dist = deltalen + offset - revlog.start(chainbase)
chainlen, compresseddeltalen = revlog._chaininfo(base)
chainlen += 1
compresseddeltalen += deltalen
return _deltainfo(
dist,
deltalen,
(header, data),
deltabase,
chainbase,
chainlen,
compresseddeltalen,
snapshotdepth,
)
def _fullsnapshotinfo(self, revinfo, curr):
rawtext = self.buildtext(revinfo)
data = self.revlog._inner.compress(rawtext)
compresseddeltalen = deltalen = dist = len(data[1]) + len(data[0])
deltabase = chainbase = curr
snapshotdepth = 0
chainlen = 1
return _deltainfo(
dist,
deltalen,
data,
deltabase,
chainbase,
chainlen,
compresseddeltalen,
snapshotdepth,
)
def finddeltainfo(self, revinfo, excluded_bases=None, target_rev=None):
"""Find an acceptable delta against a candidate revision
revinfo: information about the revision (instance of _revisioninfo)
Returns the first acceptable candidate revision, as ordered by
_candidategroups
If no suitable deltabase is found, we return delta info for a full
snapshot.
`excluded_bases` is an optional set of revision that cannot be used as
a delta base. Use this to recompute delta suitable in censor or strip
context.
"""
if target_rev is None:
target_rev = len(self.revlog)
gather_debug = self._gather_debug
cachedelta = revinfo.cachedelta
revlog = self.revlog
p1r = p2r = None
if excluded_bases is None:
excluded_bases = set()
if gather_debug:
start = util.timer()
dbg = self._one_dbg_data()
dbg['revision'] = target_rev
p1r = revlog.rev(revinfo.p1)
p2r = revlog.rev(revinfo.p2)
if p1r != nullrev:
p1_chain_len = revlog._chaininfo(p1r)[0]
else:
p1_chain_len = -1
if p2r != nullrev:
p2_chain_len = revlog._chaininfo(p2r)[0]
else:
p2_chain_len = -1
dbg['p1-chain-len'] = p1_chain_len
dbg['p2-chain-len'] = p2_chain_len
# 1) if the revision is empty, no amount of delta can beat it
#
# 2) no delta for flag processor revision (see "candelta" for why)
# not calling candelta since only one revision needs test, also to
# avoid overhead fetching flags again.
if not revinfo.textlen or revinfo.flags & REVIDX_RAWTEXT_CHANGING_FLAGS:
deltainfo = self._fullsnapshotinfo(revinfo, target_rev)
if gather_debug:
end = util.timer()
dbg['duration'] = end - start
dbg[
'delta-base'
] = deltainfo.base # pytype: disable=attribute-error
dbg['search_round_count'] = 0
dbg['using-cached-base'] = False
dbg['delta_try_count'] = 0
dbg['type'] = b"full"
dbg['snapshot-depth'] = 0
self._dbg_process_data(dbg)
return deltainfo
deltainfo = None
# If this source delta are to be forcibly reuse, let us comply early.
if (
revlog.delta_config.general_delta
and revinfo.cachedelta is not None
and revinfo.cachedelta[2] == DELTA_BASE_REUSE_FORCE
):
base = revinfo.cachedelta[0]
if base == nullrev:
dbg_type = b"full"
deltainfo = self._fullsnapshotinfo(revinfo, target_rev)
if gather_debug:
snapshotdepth = 0
elif base not in excluded_bases:
delta = revinfo.cachedelta[1]
header, data = revlog.compress(delta)
deltalen = len(header) + len(data)
if gather_debug:
offset = revlog.end(len(revlog) - 1)
chainbase = revlog.chainbase(base)
distance = deltalen + offset - revlog.start(chainbase)
chainlen, compresseddeltalen = revlog._chaininfo(base)
chainlen += 1
compresseddeltalen += deltalen
if base == p1r or base == p2r:
dbg_type = b"delta"
snapshotdepth = None
elif not revlog.issnapshot(base):
snapshotdepth = None
else:
dbg_type = b"snapshot"
snapshotdepth = revlog.snapshotdepth(base) + 1
else:
distance = None
chainbase = None
chainlen = None
compresseddeltalen = None
snapshotdepth = None
deltainfo = _deltainfo(
distance=distance,
deltalen=deltalen,
data=(header, data),
base=base,
chainbase=chainbase,
chainlen=chainlen,
compresseddeltalen=compresseddeltalen,
snapshotdepth=snapshotdepth,
)
if deltainfo is not None:
if gather_debug:
end = util.timer()
dbg['duration'] = end - start
dbg[
'delta-base'
] = deltainfo.base # pytype: disable=attribute-error
dbg['search_round_count'] = 0
dbg['using-cached-base'] = True
dbg['delta_try_count'] = 0
dbg['type'] = b"full"
if snapshotdepth is None:
dbg['snapshot-depth'] = -1
else:
dbg['snapshot-depth'] = snapshotdepth
self._dbg_process_data(dbg)
return deltainfo
# count the number of different delta we tried (for debug purpose)
dbg_try_count = 0
# count the number of "search round" we did. (for debug purpose)
dbg_try_rounds = 0
dbg_type = b'unknown'
if p1r is None:
p1r = revlog.rev(revinfo.p1)
p2r = revlog.rev(revinfo.p2)
if self._debug_search:
msg = b"DBG-DELTAS-SEARCH: SEARCH rev=%d\n"
msg %= target_rev
self._write_debug(msg)
# should we try to build a delta?
if not (len(self.revlog) and self.revlog._storedeltachains):
search_cls = _NoDeltaSearch
elif self.revlog.delta_config.sparse_revlog:
search_cls = _SparseDeltaSearch
elif self.revlog.delta_config.general_delta:
search_cls = _GeneralDeltaSearch
else:
# before general delta, there is only one possible delta base
search_cls = _PrevDeltaSearch
search = search_cls(
self.revlog,
revinfo,
p1r,
p2r,
cachedelta,
excluded_bases,
target_rev,
snapshot_cache=self._snapshot_cache,
)
while not search.done:
current_group = search.current_group
# current_group can be `None`, but not is search.done is False
# We add this assert to help pytype
assert current_group is not None
candidaterevs = current_group
dbg_try_rounds += 1
if self._debug_search:
prev = None
if deltainfo is not None:
prev = deltainfo.base
if (
cachedelta is not None
and len(candidaterevs) == 1
and cachedelta[0] in candidaterevs
):
round_type = b"cached-delta"
elif p1r in candidaterevs or p2r in candidaterevs:
round_type = b"parents"
elif prev is not None and all(c < prev for c in candidaterevs):
round_type = b"refine-down"
elif prev is not None and all(c > prev for c in candidaterevs):
round_type = b"refine-up"
else:
round_type = b"search-down"
msg = b"DBG-DELTAS-SEARCH: ROUND #%d - %d candidates - %s\n"
msg %= (dbg_try_rounds, len(candidaterevs), round_type)
self._write_debug(msg)
nominateddeltas = []
if deltainfo is not None:
if self._debug_search:
msg = (
b"DBG-DELTAS-SEARCH: CONTENDER: rev=%d - length=%d\n"
)
msg %= (deltainfo.base, deltainfo.deltalen)
self._write_debug(msg)
# if we already found a good delta,
# challenge it against refined candidates
nominateddeltas.append(deltainfo)
for candidaterev in candidaterevs:
if self._debug_search:
msg = b"DBG-DELTAS-SEARCH: CANDIDATE: rev=%d\n"
msg %= candidaterev
self._write_debug(msg)
candidate_type = None
if candidaterev == p1r:
candidate_type = b"p1"
elif candidaterev == p2r:
candidate_type = b"p2"
elif self.revlog.issnapshot(candidaterev):
candidate_type = b"snapshot-%d"
candidate_type %= self.revlog.snapshotdepth(
candidaterev
)
if candidate_type is not None:
msg = b"DBG-DELTAS-SEARCH: type=%s\n"
msg %= candidate_type
self._write_debug(msg)
msg = b"DBG-DELTAS-SEARCH: size=%d\n"
msg %= self.revlog.length(candidaterev)
self._write_debug(msg)
msg = b"DBG-DELTAS-SEARCH: base=%d\n"
msg %= self.revlog.deltaparent(candidaterev)
self._write_debug(msg)
dbg_try_count += 1
if self._debug_search:
delta_start = util.timer()
candidatedelta = self._builddeltainfo(
revinfo,
candidaterev,
target_rev=target_rev,
as_snapshot=search.current_stage == _STAGE_SNAPSHOT,
)
if self._debug_search:
delta_end = util.timer()
msg = b"DBG-DELTAS-SEARCH: delta-search-time=%f\n"
msg %= delta_end - delta_start
self._write_debug(msg)
if candidatedelta is not None:
if search.is_good_delta_info(candidatedelta):
if self._debug_search:
msg = b"DBG-DELTAS-SEARCH: DELTA: length=%d (GOOD)\n"
msg %= candidatedelta.deltalen
self._write_debug(msg)
nominateddeltas.append(candidatedelta)
elif self._debug_search:
msg = b"DBG-DELTAS-SEARCH: DELTA: length=%d (BAD)\n"
msg %= candidatedelta.deltalen
self._write_debug(msg)
elif self._debug_search:
msg = b"DBG-DELTAS-SEARCH: NO-DELTA\n"
self._write_debug(msg)
if nominateddeltas:
deltainfo = min(nominateddeltas, key=lambda x: x.deltalen)
search.next_group(deltainfo)
if deltainfo is None:
dbg_type = b"full"
deltainfo = self._fullsnapshotinfo(revinfo, target_rev)
elif deltainfo.snapshotdepth: # pytype: disable=attribute-error
dbg_type = b"snapshot"
else:
dbg_type = b"delta"
if gather_debug:
end = util.timer()
if dbg_type == b'full':
used_cached = (
cachedelta is not None
and dbg_try_rounds == 0
and dbg_try_count == 0
and cachedelta[0] == nullrev
)
else:
used_cached = (
cachedelta is not None
and dbg_try_rounds == 1
and dbg_try_count == 1
and deltainfo.base == cachedelta[0]
)
dbg['duration'] = end - start
dbg[
'delta-base'
] = deltainfo.base # pytype: disable=attribute-error
dbg['search_round_count'] = dbg_try_rounds
dbg['using-cached-base'] = used_cached
dbg['delta_try_count'] = dbg_try_count
dbg['type'] = dbg_type
if (
deltainfo.snapshotdepth # pytype: disable=attribute-error
is not None
):
dbg[
'snapshot-depth'
] = deltainfo.snapshotdepth # pytype: disable=attribute-error
else:
dbg['snapshot-depth'] = -1
self._dbg_process_data(dbg)
return deltainfo
def _one_dbg_data(self):
dbg = {
'duration': None,
'revision': None,
'delta-base': None,
'search_round_count': None,
'using-cached-base': None,
'delta_try_count': None,
'type': None,
'p1-chain-len': None,
'p2-chain-len': None,
'snapshot-depth': None,
'target-revlog': None,
}
target_revlog = b"UNKNOWN"
target_type = self.revlog.target[0]
target_key = self.revlog.target[1]
if target_type == KIND_CHANGELOG:
target_revlog = b'CHANGELOG:'
elif target_type == KIND_MANIFESTLOG:
target_revlog = b'MANIFESTLOG:'
if target_key:
target_revlog += b'%s:' % target_key
elif target_type == KIND_FILELOG:
target_revlog = b'FILELOG:'
if target_key:
target_revlog += b'%s:' % target_key
dbg['target-revlog'] = target_revlog
return dbg
def _dbg_process_data(self, dbg):
if self._debug_info is not None:
self._debug_info.append(dbg)
if self._write_debug is not None:
msg = (
b"DBG-DELTAS:"
b" %-12s"
b" rev=%d:"
b" delta-base=%d"
b" is-cached=%d"
b" - search-rounds=%d"
b" try-count=%d"
b" - delta-type=%-6s"
b" snap-depth=%d"
b" - p1-chain-length=%d"
b" p2-chain-length=%d"
b" - duration=%f"
b"\n"
)
msg %= (
dbg["target-revlog"],
dbg["revision"],
dbg["delta-base"],
dbg["using-cached-base"],
dbg["search_round_count"],
dbg["delta_try_count"],
dbg["type"],
dbg["snapshot-depth"],
dbg["p1-chain-len"],
dbg["p2-chain-len"],
dbg["duration"],
)
self._write_debug(msg)
def delta_compression(default_compression_header, deltainfo):
"""return (COMPRESSION_MODE, deltainfo)
used by revlog v2+ format to dispatch between PLAIN and DEFAULT
compression.
"""
h, d = deltainfo.data
compression_mode = COMP_MODE_INLINE
if not h and not d:
# not data to store at all... declare them uncompressed
compression_mode = COMP_MODE_PLAIN
elif not h:
t = d[0:1]
if t == b'\0':
compression_mode = COMP_MODE_PLAIN
elif t == default_compression_header:
compression_mode = COMP_MODE_DEFAULT
elif h == b'u':
# we have a more efficient way to declare uncompressed
h = b''
compression_mode = COMP_MODE_PLAIN
deltainfo = drop_u_compression(deltainfo)
return compression_mode, deltainfo