164
166
# 'unconsumed_tail'
166
168
# Do we have enough bytes already?
167
if len(self._content) >= num_bytes:
169
if num_bytes is not None and len(self._content) >= num_bytes:
171
if num_bytes is None and self._z_content_decompressor is None:
172
# We must have already decompressed everything
169
174
# If we got this far, and don't have a decompressor, something is wrong
170
175
if self._z_content_decompressor is None:
171
176
raise AssertionError(
172
177
'No decompressor to decompress %d bytes' % num_bytes)
173
178
remaining_decomp = self._z_content_decompressor.unconsumed_tail
174
if not remaining_decomp:
175
raise AssertionError('Nothing left to decompress')
176
needed_bytes = num_bytes - len(self._content)
177
# We always set max_size to 32kB over the minimum needed, so that
178
# zlib will give us as much as we really want.
179
# TODO: If this isn't good enough, we could make a loop here,
180
# that keeps expanding the request until we get enough
181
self._content += self._z_content_decompressor.decompress(
182
remaining_decomp, needed_bytes + _ZLIB_DECOMP_WINDOW)
183
if len(self._content) < num_bytes:
184
raise AssertionError('%d bytes wanted, only %d available'
185
% (num_bytes, len(self._content)))
186
if not self._z_content_decompressor.unconsumed_tail:
187
# The stream is finished
188
self._z_content_decompressor = None
179
if num_bytes is None:
181
# We don't know how much is left, but we'll decompress it all
182
self._content += self._z_content_decompressor.decompress(
184
# Note: There's what I consider a bug in zlib.decompressobj
185
# If you pass back in the entire unconsumed_tail, only
186
# this time you don't pass a max-size, it doesn't
187
# change the unconsumed_tail back to None/''.
188
# However, we know we are done with the whole stream
189
self._z_content_decompressor = None
190
# XXX: Why is this the only place in this routine we set this?
191
self._content_length = len(self._content)
193
if not remaining_decomp:
194
raise AssertionError('Nothing left to decompress')
195
needed_bytes = num_bytes - len(self._content)
196
# We always set max_size to 32kB over the minimum needed, so that
197
# zlib will give us as much as we really want.
198
# TODO: If this isn't good enough, we could make a loop here,
199
# that keeps expanding the request until we get enough
200
self._content += self._z_content_decompressor.decompress(
201
remaining_decomp, needed_bytes + _ZLIB_DECOMP_WINDOW)
202
if len(self._content) < num_bytes:
203
raise AssertionError('%d bytes wanted, only %d available'
204
% (num_bytes, len(self._content)))
205
if not self._z_content_decompressor.unconsumed_tail:
206
# The stream is finished
207
self._z_content_decompressor = None
190
209
def _parse_bytes(self, bytes, pos):
191
210
"""Read the various lengths from the header.
537
549
# time (self._block._content) is a little expensive.
538
550
self._block._ensure_content(self._last_byte)
540
def _check_rebuild_action(self):
552
def _check_rebuild_block(self):
541
553
"""Check to see if our block should be repacked."""
542
554
total_bytes_used = 0
543
555
last_byte_used = 0
544
556
for factory in self._factories:
545
557
total_bytes_used += factory._end - factory._start
546
if last_byte_used < factory._end:
547
last_byte_used = factory._end
548
# If we are using more than half of the bytes from the block, we have
549
# nothing else to check
558
last_byte_used = max(last_byte_used, factory._end)
559
# If we are using most of the bytes from the block, we have nothing
560
# else to check (currently more that 1/2)
550
561
if total_bytes_used * 2 >= self._block._content_length:
551
return None, last_byte_used, total_bytes_used
552
# We are using less than 50% of the content. Is the content we are
553
# using at the beginning of the block? If so, we can just trim the
554
# tail, rather than rebuilding from scratch.
563
# Can we just strip off the trailing bytes? If we are going to be
564
# transmitting more than 50% of the front of the content, go ahead
555
565
if total_bytes_used * 2 > last_byte_used:
556
return 'trim', last_byte_used, total_bytes_used
566
self._trim_block(last_byte_used)
558
569
# We are using a small amount of the data, and it isn't just packed
559
570
# nicely at the front, so rebuild the content.
566
577
# expanding many deltas into fulltexts, as well.
567
578
# If we build a cheap enough 'strip', then we could try a strip,
568
579
# if that expands the content, we then rebuild.
569
return 'rebuild', last_byte_used, total_bytes_used
571
def check_is_well_utilized(self):
572
"""Is the current block considered 'well utilized'?
574
This heuristic asks if the current block considers itself to be a fully
575
developed group, rather than just a loose collection of data.
577
if len(self._factories) == 1:
578
# A block of length 1 could be improved by combining with other
579
# groups - don't look deeper. Even larger than max size groups
580
# could compress well with adjacent versions of the same thing.
582
action, last_byte_used, total_bytes_used = self._check_rebuild_action()
583
block_size = self._block._content_length
584
if total_bytes_used < block_size * self._max_cut_fraction:
585
# This block wants to trim itself small enough that we want to
586
# consider it under-utilized.
588
# TODO: This code is meant to be the twin of _insert_record_stream's
589
# 'start_new_block' logic. It would probably be better to factor
590
# out that logic into a shared location, so that it stays
592
# We currently assume a block is properly utilized whenever it is >75%
593
# of the size of a 'full' block. In normal operation, a block is
594
# considered full when it hits 4MB of same-file content. So any block
595
# >3MB is 'full enough'.
596
# The only time this isn't true is when a given block has large-object
597
# content. (a single file >4MB, etc.)
598
# Under these circumstances, we allow a block to grow to
599
# 2 x largest_content. Which means that if a given block had a large
600
# object, it may actually be under-utilized. However, given that this
601
# is 'pack-on-the-fly' it is probably reasonable to not repack large
602
# content blobs on-the-fly. Note that because we return False for all
603
# 1-item blobs, we will repack them; we may wish to reevaluate our
604
# treatment of large object blobs in the future.
605
if block_size >= self._full_enough_block_size:
607
# If a block is <3MB, it still may be considered 'full' if it contains
608
# mixed content. The current rule is 2MB of mixed content is considered
609
# full. So check to see if this block contains mixed content, and
610
# set the threshold appropriately.
612
for factory in self._factories:
613
prefix = factory.key[:-1]
614
if common_prefix is None:
615
common_prefix = prefix
616
elif prefix != common_prefix:
617
# Mixed content, check the size appropriately
618
if block_size >= self._full_enough_mixed_block_size:
621
# The content failed both the mixed check and the single-content check
622
# so obviously it is not fully utilized
623
# TODO: there is one other constraint that isn't being checked
624
# namely, that the entries in the block are in the appropriate
625
# order. For example, you could insert the entries in exactly
626
# reverse groupcompress order, and we would think that is ok.
627
# (all the right objects are in one group, and it is fully
628
# utilized, etc.) For now, we assume that case is rare,
629
# especially since we should always fetch in 'groupcompress'
633
def _check_rebuild_block(self):
634
action, last_byte_used, total_bytes_used = self._check_rebuild_action()
638
self._trim_block(last_byte_used)
639
elif action == 'rebuild':
640
self._rebuild_block()
642
raise ValueError('unknown rebuild action: %r' % (action,))
580
self._rebuild_block()
644
582
def _wire_bytes(self):
645
583
"""Return a byte stream suitable for transmitting over the wire."""
1041
978
versioned_files.stream.close()
1044
class _BatchingBlockFetcher(object):
1045
"""Fetch group compress blocks in batches.
1047
:ivar total_bytes: int of expected number of bytes needed to fetch the
1048
currently pending batch.
1051
def __init__(self, gcvf, locations):
1053
self.locations = locations
1055
self.batch_memos = {}
1056
self.memos_to_get = []
1057
self.total_bytes = 0
1058
self.last_read_memo = None
1061
def add_key(self, key):
1062
"""Add another to key to fetch.
1064
:return: The estimated number of bytes needed to fetch the batch so
1067
self.keys.append(key)
1068
index_memo, _, _, _ = self.locations[key]
1069
read_memo = index_memo[0:3]
1070
# Three possibilities for this read_memo:
1071
# - it's already part of this batch; or
1072
# - it's not yet part of this batch, but is already cached; or
1073
# - it's not yet part of this batch and will need to be fetched.
1074
if read_memo in self.batch_memos:
1075
# This read memo is already in this batch.
1076
return self.total_bytes
1078
cached_block = self.gcvf._group_cache[read_memo]
1080
# This read memo is new to this batch, and the data isn't cached
1082
self.batch_memos[read_memo] = None
1083
self.memos_to_get.append(read_memo)
1084
byte_length = read_memo[2]
1085
self.total_bytes += byte_length
1087
# This read memo is new to this batch, but cached.
1088
# Keep a reference to the cached block in batch_memos because it's
1089
# certain that we'll use it when this batch is processed, but
1090
# there's a risk that it would fall out of _group_cache between now
1092
self.batch_memos[read_memo] = cached_block
1093
return self.total_bytes
1095
def _flush_manager(self):
1096
if self.manager is not None:
1097
for factory in self.manager.get_record_stream():
1100
self.last_read_memo = None
1102
def yield_factories(self, full_flush=False):
1103
"""Yield factories for keys added since the last yield. They will be
1104
returned in the order they were added via add_key.
1106
:param full_flush: by default, some results may not be returned in case
1107
they can be part of the next batch. If full_flush is True, then
1108
all results are returned.
1110
if self.manager is None and not self.keys:
1112
# Fetch all memos in this batch.
1113
blocks = self.gcvf._get_blocks(self.memos_to_get)
1114
# Turn blocks into factories and yield them.
1115
memos_to_get_stack = list(self.memos_to_get)
1116
memos_to_get_stack.reverse()
1117
for key in self.keys:
1118
index_memo, _, parents, _ = self.locations[key]
1119
read_memo = index_memo[:3]
1120
if self.last_read_memo != read_memo:
1121
# We are starting a new block. If we have a
1122
# manager, we have found everything that fits for
1123
# now, so yield records
1124
for factory in self._flush_manager():
1126
# Now start a new manager.
1127
if memos_to_get_stack and memos_to_get_stack[-1] == read_memo:
1128
# The next block from _get_blocks will be the block we
1130
block_read_memo, block = blocks.next()
1131
if block_read_memo != read_memo:
1132
raise AssertionError(
1133
"block_read_memo out of sync with read_memo"
1134
"(%r != %r)" % (block_read_memo, read_memo))
1135
self.batch_memos[read_memo] = block
1136
memos_to_get_stack.pop()
1138
block = self.batch_memos[read_memo]
1139
self.manager = _LazyGroupContentManager(block)
1140
self.last_read_memo = read_memo
1141
start, end = index_memo[3:5]
1142
self.manager.add_factory(key, parents, start, end)
1144
for factory in self._flush_manager():
1147
self.batch_memos.clear()
1148
del self.memos_to_get[:]
1149
self.total_bytes = 0
1152
981
class GroupCompressVersionedFiles(VersionedFiles):
1153
982
"""A group-compress based VersionedFiles implementation."""
1155
def __init__(self, index, access, delta=True, _unadded_refs=None):
984
def __init__(self, index, access, delta=True):
1156
985
"""Create a GroupCompressVersionedFiles object.
1158
987
:param index: The index object storing access and graph data.
1159
988
:param access: The access object storing raw data.
1160
989
:param delta: Whether to delta compress or just entropy compress.
1161
:param _unadded_refs: private parameter, don't use.
1163
991
self._index = index
1164
992
self._access = access
1165
993
self._delta = delta
1166
if _unadded_refs is None:
1168
self._unadded_refs = _unadded_refs
994
self._unadded_refs = {}
1169
995
self._group_cache = LRUSizeCache(max_size=50*1024*1024)
1170
996
self._fallback_vfs = []
1172
def without_fallbacks(self):
1173
"""Return a clone of this object without any fallbacks configured."""
1174
return GroupCompressVersionedFiles(self._index, self._access,
1175
self._delta, _unadded_refs=dict(self._unadded_refs))
1177
998
def add_lines(self, key, parents, lines, parent_texts=None,
1178
999
left_matching_blocks=None, nostore_sha=None, random_id=False,
1179
1000
check_content=True):
1252
1073
def annotate(self, key):
1253
1074
"""See VersionedFiles.annotate."""
1254
ann = annotate.Annotator(self)
1255
return ann.annotate_flat(key)
1257
def get_annotator(self):
1258
return annotate.Annotator(self)
1260
def check(self, progress_bar=None, keys=None):
1076
parent_map = self.get_parent_map([key])
1078
raise errors.RevisionNotPresent(key, self)
1079
if parent_map[key] is not None:
1080
parent_map = dict((k, v) for k, v in graph.iter_ancestry([key])
1082
keys = parent_map.keys()
1085
parent_map = {key:()}
1086
# We used Graph(self) to load the parent_map, but now that we have it,
1087
# we can just query the parent map directly, so create a KnownGraph
1088
heads_provider = _mod_graph.KnownGraph(parent_map)
1090
reannotate = annotate.reannotate
1091
for record in self.get_record_stream(keys, 'topological', True):
1093
lines = osutils.chunks_to_lines(record.get_bytes_as('chunked'))
1094
parent_lines = [parent_cache[parent] for parent in parent_map[key]]
1095
parent_cache[key] = list(
1096
reannotate(parent_lines, lines, key, None, heads_provider))
1097
return parent_cache[key]
1099
def check(self, progress_bar=None):
1261
1100
"""See VersionedFiles.check()."""
1264
for record in self.get_record_stream(keys, 'unordered', True):
1265
record.get_bytes_as('fulltext')
1267
return self.get_record_stream(keys, 'unordered', True)
1269
def clear_cache(self):
1270
"""See VersionedFiles.clear_cache()"""
1271
self._group_cache.clear()
1272
self._index._graph_index.clear_cache()
1273
self._index._int_cache.clear()
1102
for record in self.get_record_stream(keys, 'unordered', True):
1103
record.get_bytes_as('fulltext')
1275
1105
def _check_add(self, key, lines, random_id, check_content):
1276
1106
"""check that version_id and lines are safe to add."""
1335
1149
missing.difference_update(set(new_result))
1336
1150
return result, source_results
1338
def _get_blocks(self, read_memos):
1339
"""Get GroupCompressBlocks for the given read_memos.
1341
:returns: a series of (read_memo, block) pairs, in the order they were
1345
for read_memo in read_memos:
1347
block = self._group_cache[read_memo]
1351
cached[read_memo] = block
1353
not_cached_seen = set()
1354
for read_memo in read_memos:
1355
if read_memo in cached:
1356
# Don't fetch what we already have
1358
if read_memo in not_cached_seen:
1359
# Don't try to fetch the same data twice
1361
not_cached.append(read_memo)
1362
not_cached_seen.add(read_memo)
1363
raw_records = self._access.get_raw_records(not_cached)
1364
for read_memo in read_memos:
1366
yield read_memo, cached[read_memo]
1368
# Read the block, and cache it.
1369
zdata = raw_records.next()
1370
block = GroupCompressBlock.from_bytes(zdata)
1371
self._group_cache[read_memo] = block
1372
cached[read_memo] = block
1373
yield read_memo, block
1152
def _get_block(self, index_memo):
1153
read_memo = index_memo[0:3]
1156
block = self._group_cache[read_memo]
1159
zdata = self._access.get_raw_records([read_memo]).next()
1160
# decompress - whole thing - this is not a bug, as it
1161
# permits caching. We might want to store the partially
1162
# decompresed group and decompress object, so that recent
1163
# texts are not penalised by big groups.
1164
block = GroupCompressBlock.from_bytes(zdata)
1165
self._group_cache[read_memo] = block
1167
# print len(zdata), len(plain)
1168
# parse - requires split_lines, better to have byte offsets
1169
# here (but not by much - we only split the region for the
1170
# recipe, and we often want to end up with lines anyway.
1375
1173
def get_missing_compression_parent_keys(self):
1376
1174
"""Return the keys of missing compression parents.
1542
1340
unadded_keys, source_result)
1543
1341
for key in missing:
1544
1342
yield AbsentContentFactory(key)
1545
# Batch up as many keys as we can until either:
1546
# - we encounter an unadded ref, or
1547
# - we run out of keys, or
1548
# - the total bytes to retrieve for this batch > BATCH_SIZE
1549
batcher = _BatchingBlockFetcher(self, locations)
1344
last_read_memo = None
1345
# TODO: This works fairly well at batching up existing groups into a
1346
# streamable format, and possibly allowing for taking one big
1347
# group and splitting it when it isn't fully utilized.
1348
# However, it doesn't allow us to find under-utilized groups and
1349
# combine them into a bigger group on the fly.
1350
# (Consider the issue with how chk_map inserts texts
1351
# one-at-a-time.) This could be done at insert_record_stream()
1352
# time, but it probably would decrease the number of
1353
# bytes-on-the-wire for fetch.
1550
1354
for source, keys in source_keys:
1551
1355
if source is self:
1552
1356
for key in keys:
1553
1357
if key in self._unadded_refs:
1554
# Flush batch, then yield unadded ref from
1556
for factory in batcher.yield_factories(full_flush=True):
1358
if manager is not None:
1359
for factory in manager.get_record_stream():
1361
last_read_memo = manager = None
1558
1362
bytes, sha1 = self._compressor.extract(key)
1559
1363
parents = self._unadded_refs[key]
1560
1364
yield FulltextContentFactory(key, parents, sha1, bytes)
1562
if batcher.add_key(key) > BATCH_SIZE:
1563
# Ok, this batch is big enough. Yield some results.
1564
for factory in batcher.yield_factories():
1366
index_memo, _, parents, (method, _) = locations[key]
1367
read_memo = index_memo[0:3]
1368
if last_read_memo != read_memo:
1369
# We are starting a new block. If we have a
1370
# manager, we have found everything that fits for
1371
# now, so yield records
1372
if manager is not None:
1373
for factory in manager.get_record_stream():
1375
# Now start a new manager
1376
block = self._get_block(index_memo)
1377
manager = _LazyGroupContentManager(block)
1378
last_read_memo = read_memo
1379
start, end = index_memo[3:5]
1380
manager.add_factory(key, parents, start, end)
1567
for factory in batcher.yield_factories(full_flush=True):
1382
if manager is not None:
1383
for factory in manager.get_record_stream():
1385
last_read_memo = manager = None
1569
1386
for record in source.get_record_stream(keys, ordering,
1570
1387
include_delta_closure):
1572
for factory in batcher.yield_factories(full_flush=True):
1389
if manager is not None:
1390
for factory in manager.get_record_stream():
1575
1393
def get_sha1s(self, keys):
1576
1394
"""See VersionedFiles.get_sha1s()."""
1663
1480
if reuse_blocks:
1664
1481
# If the reuse_blocks flag is set, check to see if we can just
1665
1482
# copy a groupcompress block as-is.
1666
# We only check on the first record (groupcompress-block) not
1667
# on all of the (groupcompress-block-ref) entries.
1668
# The reuse_this_block flag is then kept for as long as
1669
if record.storage_kind == 'groupcompress-block':
1670
# Check to see if we really want to re-use this block
1671
insert_manager = record._manager
1672
reuse_this_block = insert_manager.check_is_well_utilized()
1674
reuse_this_block = False
1675
if reuse_this_block:
1676
# We still want to reuse this block
1677
1483
if record.storage_kind == 'groupcompress-block':
1678
1484
# Insert the raw block into the target repo
1679
1485
insert_manager = record._manager
1486
insert_manager._check_rebuild_block()
1680
1487
bytes = record._manager._block.to_bytes()
1681
1488
_, start, length = self._access.add_raw_records(
1682
1489
[(None, len(bytes))], bytes)[0]
1828
1624
:param track_external_parent_refs: As keys are added, keep track of the
1829
1625
keys they reference, so that we can query get_missing_parents(),
1831
:param inconsistency_fatal: When asked to add records that are already
1832
present, and the details are inconsistent with the existing
1833
record, raise an exception instead of warning (and skipping the
1836
1628
self._add_callback = add_callback
1837
1629
self._graph_index = graph_index
1838
1630
self._parents = parents
1839
1631
self.has_graph = parents
1840
1632
self._is_locked = is_locked
1841
self._inconsistency_fatal = inconsistency_fatal
1842
# GroupCompress records tend to have the same 'group' start + offset
1843
# repeated over and over, this creates a surplus of ints
1844
self._int_cache = {}
1845
1633
if track_external_parent_refs:
1846
self._key_dependencies = knit._KeyRefs(
1847
track_new_keys=track_new_keys)
1634
self._key_dependencies = knit._KeyRefs()
1849
1636
self._key_dependencies = None
1883
1670
if not random_id:
1884
1671
present_nodes = self._get_entries(keys)
1885
1672
for (index, key, value, node_refs) in present_nodes:
1886
# Sometimes these are passed as a list rather than a tuple
1887
node_refs = static_tuple.as_tuples(node_refs)
1888
passed = static_tuple.as_tuples(keys[key])
1889
if node_refs != passed[1]:
1890
details = '%s %s %s' % (key, (value, node_refs), passed)
1891
if self._inconsistency_fatal:
1892
raise errors.KnitCorrupt(self, "inconsistent details"
1893
" in add_records: %s" %
1896
trace.warning("inconsistent details in skipped"
1897
" record: %s", details)
1673
if node_refs != keys[key][1]:
1674
raise errors.KnitCorrupt(self, "inconsistent details in add_records"
1675
": %s %s" % ((value, node_refs), keys[key]))
2026
1796
"""Convert an index value to position details."""
2027
1797
bits = node[2].split(' ')
2028
1798
# It would be nice not to read the entire gzip.
2029
# start and stop are put into _int_cache because they are very common.
2030
# They define the 'group' that an entry is in, and many groups can have
2031
# thousands of objects.
2032
# Branching Launchpad, for example, saves ~600k integers, at 12 bytes
2033
# each, or about 7MB. Note that it might be even more when you consider
2034
# how PyInt is allocated in separate slabs. And you can't return a slab
2035
# to the OS if even 1 int on it is in use. Note though that Python uses
2036
# a LIFO when re-using PyInt slots, which probably causes more
2038
1799
start = int(bits[0])
2039
start = self._int_cache.setdefault(start, start)
2040
1800
stop = int(bits[1])
2041
stop = self._int_cache.setdefault(stop, stop)
2042
1801
basis_end = int(bits[2])
2043
1802
delta_end = int(bits[3])
2044
# We can't use StaticTuple here, because node[0] is a BTreeGraphIndex
2046
return (node[0], start, stop, basis_end, delta_end)
1803
return node[0], start, stop, basis_end, delta_end
2048
1805
def scan_unvalidated_index(self, graph_index):
2049
1806
"""Inform this _GCGraphIndex that there is an unvalidated index.
2051
1808
This allows this _GCGraphIndex to keep track of any missing
2052
1809
compression parents we may want to have filled in to make those
2053
indices valid. It also allows _GCGraphIndex to track any new keys.
2055
1812
:param graph_index: A GraphIndex
2057
key_dependencies = self._key_dependencies
2058
if key_dependencies is None:
2060
for node in graph_index.iter_all_entries():
2061
# Add parent refs from graph_index (and discard parent refs
2062
# that the graph_index has).
2063
key_dependencies.add_references(node[1], node[3][0])
1814
if self._key_dependencies is not None:
1815
# Add parent refs from graph_index (and discard parent refs that
1816
# the graph_index has).
1817
add_refs = self._key_dependencies.add_references
1818
for node in graph_index.iter_all_entries():
1819
add_refs(node[1], node[3][0])
2066
1823
from bzrlib._groupcompress_py import (
added
removed
bzrlib/groupcompress.py
