186
179
combine mem with the first and second indexes, creating a new one of
187
180
size 4x. On the fifth create a single new one, etc.
189
if self._combine_backing_indices:
190
(new_backing_file, size,
191
backing_pos) = self._spill_mem_keys_and_combine()
193
new_backing_file, size = self._spill_mem_keys_without_combining()
194
# Note: The transport here isn't strictly needed, because we will use
195
# direct access to the new_backing._file object
196
new_backing = BTreeGraphIndex(get_transport('.'), '<temp>', size)
197
# GC will clean up the file
198
new_backing._file = new_backing_file
199
if self._combine_backing_indices:
200
if len(self._backing_indices) == backing_pos:
201
self._backing_indices.append(None)
202
self._backing_indices[backing_pos] = new_backing
203
for backing_pos in range(backing_pos):
204
self._backing_indices[backing_pos] = None
206
self._backing_indices.append(new_backing)
208
self._nodes_by_key = None
210
def _spill_mem_keys_without_combining(self):
211
return self._write_nodes(self._iter_mem_nodes(), allow_optimize=False)
213
def _spill_mem_keys_and_combine(self):
214
182
iterators_to_combine = [self._iter_mem_nodes()]
216
184
for pos, backing in enumerate(self._backing_indices):
220
188
iterators_to_combine.append(backing.iter_all_entries())
221
189
backing_pos = pos + 1
222
190
new_backing_file, size = \
223
self._write_nodes(self._iter_smallest(iterators_to_combine),
224
allow_optimize=False)
225
return new_backing_file, size, backing_pos
191
self._write_nodes(self._iter_smallest(iterators_to_combine))
192
dir_path, base_name = osutils.split(new_backing_file.name)
193
# Note: The transport here isn't strictly needed, because we will use
194
# direct access to the new_backing._file object
195
new_backing = BTreeGraphIndex(get_transport(dir_path),
197
# GC will clean up the file
198
new_backing._file = new_backing_file
199
if len(self._backing_indices) == backing_pos:
200
self._backing_indices.append(None)
201
self._backing_indices[backing_pos] = new_backing
202
for pos in range(backing_pos):
203
self._backing_indices[pos] = None
206
self._nodes_by_key = None
227
208
def add_nodes(self, nodes):
228
209
"""Add nodes to the index.
341
313
# This will be padded, hence the -100
342
314
new_row.writer = chunk_writer.ChunkWriter(
343
315
_PAGE_SIZE - _RESERVED_HEADER_BYTES,
345
optimize_for_size=self._optimize_for_size)
346
317
new_row.writer.write(_INTERNAL_FLAG)
347
318
new_row.writer.write(_INTERNAL_OFFSET +
348
319
str(rows[1].nodes - 1) + "\n")
349
320
new_row.writer.write(key_line)
350
self._add_key(string_key, line, rows, allow_optimize=allow_optimize)
321
self._add_key(string_key, line, rows)
352
def _write_nodes(self, node_iterator, allow_optimize=True):
323
def _write_nodes(self, node_iterator):
353
324
"""Write node_iterator out as a B+Tree.
355
326
:param node_iterator: An iterator of sorted nodes. Each node should
356
327
match the output given by iter_all_entries.
357
:param allow_optimize: If set to False, prevent setting the optimize
358
flag when writing out. This is used by the _spill_mem_keys_to_disk
360
328
:return: A file handle for a temporary file containing a B+Tree for
463
427
efficient order for the index (keys iteration order in this case).
466
# Note: We don't use keys.intersection() here. If you read the C api,
467
# set.intersection(other) special cases when other is a set and
468
# will iterate the smaller of the two and lookup in the other.
469
# It does *not* do this for any other type (even dict, unlike
470
# some other set functions.) Since we expect keys is generally <<
471
# self._nodes, it is faster to iterate over it in a list
474
local_keys = [key for key in keys if key in nodes]
475
430
if self.reference_lists:
476
for key in local_keys:
431
for key in keys.intersection(self._keys):
432
node = self._nodes[key]
478
433
yield self, key, node[1], node[0]
480
for key in local_keys:
435
for key in keys.intersection(self._keys):
436
node = self._nodes[key]
482
437
yield self, key, node[1]
483
# Find things that are in backing indices that have not been handled
485
if not self._backing_indices:
486
return # We won't find anything there either
487
# Remove all of the keys that we found locally
488
keys.difference_update(local_keys)
438
keys.difference_update(self._keys)
489
439
for backing in self._backing_indices:
490
440
if backing is None:
604
554
class _LeafNode(object):
605
555
"""A leaf node for a serialised B+Tree index."""
607
__slots__ = ('keys', 'min_key', 'max_key')
609
557
def __init__(self, bytes, key_length, ref_list_length):
610
558
"""Parse bytes to create a leaf node object."""
611
559
# splitlines mangles the \r delimiters.. don't use it.
612
key_list = _btree_serializer._parse_leaf_lines(bytes,
613
key_length, ref_list_length)
615
self.min_key = key_list[0][0]
616
self.max_key = key_list[-1][0]
618
self.min_key = self.max_key = None
619
self.keys = dict(key_list)
560
self.keys = dict(_btree_serializer._parse_leaf_lines(bytes,
561
key_length, ref_list_length))
622
564
class _InternalNode(object):
623
565
"""An internal node for a serialised B+Tree index."""
625
__slots__ = ('keys', 'offset')
627
567
def __init__(self, bytes):
628
568
"""Parse bytes to create an internal node object."""
629
569
# splitlines mangles the \r delimiters.. don't use it.
719
644
if start_of_leaves is None:
720
645
start_of_leaves = self._row_offsets[-2]
721
646
if node_pos < start_of_leaves:
722
self._internal_node_cache[node_pos] = node
647
self._internal_node_cache.add(node_pos, node)
724
self._leaf_node_cache[node_pos] = node
649
self._leaf_node_cache.add(node_pos, node)
725
650
found[node_pos] = node
728
653
def _compute_recommended_pages(self):
729
"""Convert transport's recommended_page_size into btree pages.
731
recommended_page_size is in bytes, we want to know how many _PAGE_SIZE
732
pages fit in that length.
654
"""Given the transport's recommended_page_size, determine num pages."""
734
655
recommended_read = self._transport.recommended_page_size()
735
656
recommended_pages = int(math.ceil(recommended_read /
736
657
float(_PAGE_SIZE)))
737
658
return recommended_pages
739
def _compute_total_pages_in_index(self):
740
"""How many pages are in the index.
742
If we have read the header we will use the value stored there.
743
Otherwise it will be computed based on the length of the index.
660
def _compute_num_pages(self):
661
"""Determine the offset to the last page in this index."""
745
662
if self._size is None:
746
raise AssertionError('_compute_total_pages_in_index should not be'
747
' called when self._size is None')
663
raise AssertionError('_compute_num_pages should not be called'
664
' when self._size is None')
748
665
if self._root_node is not None:
749
666
# This is the number of pages as defined by the header
750
667
return self._row_offsets[-1]
751
668
# This is the number of pages as defined by the size of the index. They
752
669
# should be indentical.
753
total_pages = int(math.ceil(self._size / float(_PAGE_SIZE)))
670
num_pages = int(math.ceil(self._size / float(_PAGE_SIZE)))
756
def _expand_offsets(self, offsets):
757
"""Find extra pages to download.
673
def _expand_nodes(self, node_indexes):
674
"""Find extra nodes to download.
759
676
The idea is that we always want to make big-enough requests (like 64kB
760
677
for http), so that we don't waste round trips. So given the entries
761
that we already have cached and the new pages being downloaded figure
678
that we already have cached, and the new nodes being downloaded, figure
762
679
out what other pages we might want to read.
764
See also doc/developers/btree_index_prefetch.txt for more details.
766
:param offsets: The offsets to be read
767
:return: A list of offsets to download
681
:param node_indexes: The nodes that have been requested to read.
682
:return: A new list of nodes to download
769
684
if 'index' in debug.debug_flags:
770
trace.mutter('expanding: %s\toffsets: %s', self._name, offsets)
685
trace.mutter('expanding: %s\tnodes: %s', self._name, node_indexes)
772
if len(offsets) >= self._recommended_pages:
687
if len(node_indexes) >= self._recommended_pages:
773
688
# Don't add more, we are already requesting more than enough
774
689
if 'index' in debug.debug_flags:
775
690
trace.mutter(' not expanding large request (%s >= %s)',
776
len(offsets), self._recommended_pages)
691
len(node_indexes), self._recommended_pages)
778
693
if self._size is None:
779
694
# Don't try anything, because we don't know where the file ends
780
695
if 'index' in debug.debug_flags:
781
696
trace.mutter(' not expanding without knowing index size')
783
total_pages = self._compute_total_pages_in_index()
784
cached_offsets = self._get_offsets_to_cached_pages()
698
num_pages = self._compute_num_pages()
699
# The idea here is to get nodes "next to" the ones we are already
701
cached_keys = self._get_cached_keys()
785
703
# If reading recommended_pages would read the rest of the index, just
787
if total_pages - len(cached_offsets) <= self._recommended_pages:
705
if num_pages - len(cached_keys) <= self._recommended_pages:
788
706
# Read whatever is left
790
expanded = [x for x in xrange(total_pages)
791
if x not in cached_offsets]
708
expanded = [x for x in xrange(num_pages)
709
if x not in cached_keys]
793
expanded = range(total_pages)
711
expanded = range(num_pages)
794
712
if 'index' in debug.debug_flags:
795
713
trace.mutter(' reading all unread pages: %s', expanded)
813
731
# start expanding our requests.
814
732
if 'index' in debug.debug_flags:
815
733
trace.mutter(' not expanding on first reads')
817
final_offsets = self._expand_to_neighbors(offsets, cached_offsets,
820
final_offsets = sorted(final_offsets)
736
# Expand requests to neighbors until we have at least
737
# recommended_pages to request. We only want to expand requests
738
# within a given layer. We cheat a little bit and assume all
739
# requests will be in the same layer. This is true given the
740
# current design, but if it changes this algorithm may perform
742
final_nodes = set(node_indexes)
744
new_tips = set(final_nodes)
745
while len(final_nodes) < self._recommended_pages and new_tips:
749
first, end = self._find_layer_first_and_end(pos)
752
and previous not in cached_keys
753
and previous not in final_nodes
754
and previous >= first):
755
next_tips.add(previous)
757
if (after < num_pages
758
and after not in cached_keys
759
and after not in final_nodes
762
# This would keep us from going bigger than
763
# recommended_pages by only expanding the first nodes.
764
# However, if we are making a 'wide' request, it is
765
# reasonable to expand all points equally.
766
# if len(final_nodes) > recommended_pages:
768
final_nodes.update(next_tips)
771
final_nodes = sorted(final_nodes)
821
772
if 'index' in debug.debug_flags:
822
trace.mutter('expanded: %s', final_offsets)
825
def _expand_to_neighbors(self, offsets, cached_offsets, total_pages):
826
"""Expand requests to neighbors until we have enough pages.
828
This is called from _expand_offsets after policy has determined that we
830
We only want to expand requests within a given layer. We cheat a little
831
bit and assume all requests will be in the same layer. This is true
832
given the current design, but if it changes this algorithm may perform
835
:param offsets: requested offsets
836
:param cached_offsets: offsets for pages we currently have cached
837
:return: A set() of offsets after expansion
839
final_offsets = set(offsets)
841
new_tips = set(final_offsets)
842
while len(final_offsets) < self._recommended_pages and new_tips:
846
first, end = self._find_layer_first_and_end(pos)
849
and previous not in cached_offsets
850
and previous not in final_offsets
851
and previous >= first):
852
next_tips.add(previous)
854
if (after < total_pages
855
and after not in cached_offsets
856
and after not in final_offsets
859
# This would keep us from going bigger than
860
# recommended_pages by only expanding the first offsets.
861
# However, if we are making a 'wide' request, it is
862
# reasonable to expand all points equally.
863
# if len(final_offsets) > recommended_pages:
865
final_offsets.update(next_tips)
869
def clear_cache(self):
870
"""Clear out any cached/memoized values.
872
This can be called at any time, but generally it is used when we have
873
extracted some information, but don't expect to be requesting any more
876
# Note that we don't touch self._root_node or self._internal_node_cache
877
# We don't expect either of those to be big, and it can save
878
# round-trips in the future. We may re-evaluate this if InternalNode
879
# memory starts to be an issue.
880
self._leaf_node_cache.clear()
882
def external_references(self, ref_list_num):
883
if self._root_node is None:
884
self._get_root_node()
885
if ref_list_num + 1 > self.node_ref_lists:
886
raise ValueError('No ref list %d, index has %d ref lists'
887
% (ref_list_num, self.node_ref_lists))
890
for node in self.iter_all_entries():
892
refs.update(node[3][ref_list_num])
773
trace.mutter('expanded: %s', final_nodes)
895
776
def _find_layer_first_and_end(self, offset):
896
777
"""Find the start/stop nodes for the layer corresponding to offset.
946
827
return self._get_nodes(self._internal_node_cache, node_indexes)
948
def _cache_leaf_values(self, nodes):
949
"""Cache directly from key => value, skipping the btree."""
829
def _get_leaf_nodes(self, node_indexes):
830
"""Get a bunch of nodes, from cache or disk."""
831
found = self._get_nodes(self._leaf_node_cache, node_indexes)
950
832
if self._leaf_value_cache is not None:
951
for node in nodes.itervalues():
833
for node in found.itervalues():
952
834
for key, value in node.keys.iteritems():
953
835
if key in self._leaf_value_cache:
954
836
# Don't add the rest of the keys, we've seen this node
957
839
self._leaf_value_cache[key] = value
959
def _get_leaf_nodes(self, node_indexes):
960
"""Get a bunch of nodes, from cache or disk."""
961
found = self._get_nodes(self._leaf_node_cache, node_indexes)
962
self._cache_leaf_values(found)
965
842
def iter_all_entries(self):
976
853
"iter_all_entries scales with size of history.")
977
854
if not self.key_count():
979
if self._row_offsets[-1] == 1:
980
# There is only the root node, and we read that via key_count()
981
if self.node_ref_lists:
982
for key, (value, refs) in sorted(self._root_node.keys.items()):
983
yield (self, key, value, refs)
985
for key, (value, refs) in sorted(self._root_node.keys.items()):
986
yield (self, key, value)
988
856
start_of_leaves = self._row_offsets[-2]
989
857
end_of_leaves = self._row_offsets[-1]
990
needed_offsets = range(start_of_leaves, end_of_leaves)
991
if needed_offsets == [0]:
992
# Special case when we only have a root node, as we have already
994
nodes = [(0, self._root_node)]
996
nodes = self._read_nodes(needed_offsets)
858
needed_nodes = range(start_of_leaves, end_of_leaves)
997
859
# We iterate strictly in-order so that we can use this function
998
860
# for spilling index builds to disk.
999
861
if self.node_ref_lists:
1000
for _, node in nodes:
862
for _, node in self._read_nodes(needed_nodes):
1001
863
for key, (value, refs) in sorted(node.keys.items()):
1002
864
yield (self, key, value, refs)
1004
for _, node in nodes:
866
for _, node in self._read_nodes(needed_nodes):
1005
867
for key, (value, refs) in sorted(node.keys.items()):
1006
868
yield (self, key, value)
1087
949
output.append(cur_out)
1090
def _walk_through_internal_nodes(self, keys):
1091
"""Take the given set of keys, and find the corresponding LeafNodes.
1093
:param keys: An unsorted iterable of keys to search for
1094
:return: (nodes, index_and_keys)
1095
nodes is a dict mapping {index: LeafNode}
1096
keys_at_index is a list of tuples of [(index, [keys for Leaf])]
1098
# 6 seconds spent in miss_torture using the sorted() line.
1099
# Even with out of order disk IO it seems faster not to sort it when
1100
# large queries are being made.
1101
keys_at_index = [(0, sorted(keys))]
1103
for row_pos, next_row_start in enumerate(self._row_offsets[1:-1]):
1104
node_indexes = [idx for idx, s_keys in keys_at_index]
1105
nodes = self._get_internal_nodes(node_indexes)
1107
next_nodes_and_keys = []
1108
for node_index, sub_keys in keys_at_index:
1109
node = nodes[node_index]
1110
positions = self._multi_bisect_right(sub_keys, node.keys)
1111
node_offset = next_row_start + node.offset
1112
next_nodes_and_keys.extend([(node_offset + pos, s_keys)
1113
for pos, s_keys in positions])
1114
keys_at_index = next_nodes_and_keys
1115
# We should now be at the _LeafNodes
1116
node_indexes = [idx for idx, s_keys in keys_at_index]
1118
# TODO: We may *not* want to always read all the nodes in one
1119
# big go. Consider setting a max size on this.
1120
nodes = self._get_leaf_nodes(node_indexes)
1121
return nodes, keys_at_index
1123
952
def iter_entries(self, keys):
1124
953
"""Iterate over keys within the index.
1163
992
needed_keys = keys
1164
993
if not needed_keys:
1166
nodes, nodes_and_keys = self._walk_through_internal_nodes(needed_keys)
995
# 6 seconds spent in miss_torture using the sorted() line.
996
# Even with out of order disk IO it seems faster not to sort it when
997
# large queries are being made.
998
needed_keys = sorted(needed_keys)
1000
nodes_and_keys = [(0, needed_keys)]
1002
for row_pos, next_row_start in enumerate(self._row_offsets[1:-1]):
1003
node_indexes = [idx for idx, s_keys in nodes_and_keys]
1004
nodes = self._get_internal_nodes(node_indexes)
1006
next_nodes_and_keys = []
1007
for node_index, sub_keys in nodes_and_keys:
1008
node = nodes[node_index]
1009
positions = self._multi_bisect_right(sub_keys, node.keys)
1010
node_offset = next_row_start + node.offset
1011
next_nodes_and_keys.extend([(node_offset + pos, s_keys)
1012
for pos, s_keys in positions])
1013
nodes_and_keys = next_nodes_and_keys
1014
# We should now be at the _LeafNodes
1015
node_indexes = [idx for idx, s_keys in nodes_and_keys]
1017
# TODO: We may *not* want to always read all the nodes in one
1018
# big go. Consider setting a max size on this.
1020
nodes = self._get_leaf_nodes(node_indexes)
1167
1021
for node_index, sub_keys in nodes_and_keys:
1168
1022
if not sub_keys:
1177
1031
yield (self, next_sub_key, value)
1179
def _find_ancestors(self, keys, ref_list_num, parent_map, missing_keys):
1180
"""Find the parent_map information for the set of keys.
1182
This populates the parent_map dict and missing_keys set based on the
1183
queried keys. It also can fill out an arbitrary number of parents that
1184
it finds while searching for the supplied keys.
1186
It is unlikely that you want to call this directly. See
1187
"CombinedGraphIndex.find_ancestry()" for a more appropriate API.
1189
:param keys: A keys whose ancestry we want to return
1190
Every key will either end up in 'parent_map' or 'missing_keys'.
1191
:param ref_list_num: This index in the ref_lists is the parents we
1193
:param parent_map: {key: parent_keys} for keys that are present in this
1194
index. This may contain more entries than were in 'keys', that are
1195
reachable ancestors of the keys requested.
1196
:param missing_keys: keys which are known to be missing in this index.
1197
This may include parents that were not directly requested, but we
1198
were able to determine that they are not present in this index.
1199
:return: search_keys parents that were found but not queried to know
1200
if they are missing or present. Callers can re-query this index for
1201
those keys, and they will be placed into parent_map or missing_keys
1203
if not self.key_count():
1204
# We use key_count() to trigger reading the root node and
1205
# determining info about this BTreeGraphIndex
1206
# If we don't have any keys, then everything is missing
1207
missing_keys.update(keys)
1209
if ref_list_num >= self.node_ref_lists:
1210
raise ValueError('No ref list %d, index has %d ref lists'
1211
% (ref_list_num, self.node_ref_lists))
1213
# The main trick we are trying to accomplish is that when we find a
1214
# key listing its parents, we expect that the parent key is also likely
1215
# to sit on the same page. Allowing us to expand parents quickly
1216
# without suffering the full stack of bisecting, etc.
1217
nodes, nodes_and_keys = self._walk_through_internal_nodes(keys)
1219
# These are parent keys which could not be immediately resolved on the
1220
# page where the child was present. Note that we may already be
1221
# searching for that key, and it may actually be present [or known
1222
# missing] on one of the other pages we are reading.
1224
# We could try searching for them in the immediate previous or next
1225
# page. If they occur "later" we could put them in a pending lookup
1226
# set, and then for each node we read thereafter we could check to
1227
# see if they are present.
1228
# However, we don't know the impact of keeping this list of things
1229
# that I'm going to search for every node I come across from here on
1231
# It doesn't handle the case when the parent key is missing on a
1232
# page that we *don't* read. So we already have to handle being
1233
# re-entrant for that.
1234
# Since most keys contain a date string, they are more likely to be
1235
# found earlier in the file than later, but we would know that right
1236
# away (key < min_key), and wouldn't keep searching it on every other
1237
# page that we read.
1238
# Mostly, it is an idea, one which should be benchmarked.
1239
parents_not_on_page = set()
1241
for node_index, sub_keys in nodes_and_keys:
1244
# sub_keys is all of the keys we are looking for that should exist
1245
# on this page, if they aren't here, then they won't be found
1246
node = nodes[node_index]
1247
node_keys = node.keys
1248
parents_to_check = set()
1249
for next_sub_key in sub_keys:
1250
if next_sub_key not in node_keys:
1251
# This one is just not present in the index at all
1252
missing_keys.add(next_sub_key)
1254
value, refs = node_keys[next_sub_key]
1255
parent_keys = refs[ref_list_num]
1256
parent_map[next_sub_key] = parent_keys
1257
parents_to_check.update(parent_keys)
1258
# Don't look for things we've already found
1259
parents_to_check = parents_to_check.difference(parent_map)
1260
# this can be used to test the benefit of having the check loop
1262
# parents_not_on_page.update(parents_to_check)
1264
while parents_to_check:
1265
next_parents_to_check = set()
1266
for key in parents_to_check:
1267
if key in node_keys:
1268
value, refs = node_keys[key]
1269
parent_keys = refs[ref_list_num]
1270
parent_map[key] = parent_keys
1271
next_parents_to_check.update(parent_keys)
1273
# This parent either is genuinely missing, or should be
1274
# found on another page. Perf test whether it is better
1275
# to check if this node should fit on this page or not.
1276
# in the 'everything-in-one-pack' scenario, this *not*
1277
# doing the check is 237ms vs 243ms.
1278
# So slightly better, but I assume the standard 'lots
1279
# of packs' is going to show a reasonable improvement
1280
# from the check, because it avoids 'going around
1281
# again' for everything that is in another index
1282
# parents_not_on_page.add(key)
1283
# Missing for some reason
1284
if key < node.min_key:
1285
# in the case of bzr.dev, 3.4k/5.3k misses are
1286
# 'earlier' misses (65%)
1287
parents_not_on_page.add(key)
1288
elif key > node.max_key:
1289
# This parent key would be present on a different
1291
parents_not_on_page.add(key)
1293
# assert key != node.min_key and key != node.max_key
1294
# If it was going to be present, it would be on
1295
# *this* page, so mark it missing.
1296
missing_keys.add(key)
1297
parents_to_check = next_parents_to_check.difference(parent_map)
1298
# Might want to do another .difference() from missing_keys
1299
# parents_not_on_page could have been found on a different page, or be
1300
# known to be missing. So cull out everything that has already been
1302
search_keys = parents_not_on_page.difference(
1303
parent_map).difference(missing_keys)
1306
1033
def iter_entries_prefix(self, keys):
1307
1034
"""Iterate over keys within the index using prefix matching.
1486
1213
"""Read some nodes from disk into the LRU cache.
1488
1215
This performs a readv to get the node data into memory, and parses each
1489
node, then yields it to the caller. The nodes are requested in the
1216
node, the yields it to the caller. The nodes are requested in the
1490
1217
supplied order. If possible doing sort() on the list before requesting
1491
1218
a read may improve performance.
1493
1220
:param nodes: The nodes to read. 0 - first node, 1 - second node etc.
1496
# may be the byte string of the whole file
1498
# list of (offset, length) regions of the file that should, evenually
1499
# be read in to data_ranges, either from 'bytes' or from the transport
1501
base_offset = self._base_offset
1502
1224
for index in nodes:
1503
offset = (index * _PAGE_SIZE)
1225
offset = index * _PAGE_SIZE
1504
1226
size = _PAGE_SIZE
1506
1228
# Root node - special case
1508
1230
size = min(_PAGE_SIZE, self._size)
1510
# The only case where we don't know the size, is for very
1511
# small indexes. So we read the whole thing
1512
bytes = self._transport.get_bytes(self._name)
1513
num_bytes = len(bytes)
1514
self._size = num_bytes - base_offset
1515
# the whole thing should be parsed out of 'bytes'
1516
ranges = [(start, min(_PAGE_SIZE, num_bytes - start))
1517
for start in xrange(base_offset, num_bytes, _PAGE_SIZE)]
1232
stream = self._transport.get(self._name)
1233
start = stream.read(_PAGE_SIZE)
1234
# Avoid doing this again
1235
self._size = len(start)
1236
size = min(_PAGE_SIZE, self._size)
1520
1238
if offset > self._size:
1521
1239
raise AssertionError('tried to read past the end'
1522
1240
' of the file %s > %s'
1523
1241
% (offset, self._size))
1524
1242
size = min(size, self._size - offset)
1525
ranges.append((base_offset + offset, size))
1243
ranges.append((offset, size))
1528
elif bytes is not None:
1529
# already have the whole file
1530
data_ranges = [(start, bytes[start:start+size])
1531
for start, size in ranges]
1532
elif self._file is None:
1246
if self._file is None:
1533
1247
data_ranges = self._transport.readv(self._name, ranges)
1535
1249
data_ranges = []
added
removed
bzrlib/btree_index.py
