# Copyright (C) 2007-2010 Canonical Ltd
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
"""Indexing facilities."""
__all__ = [
'CombinedGraphIndex',
'GraphIndex',
'GraphIndexBuilder',
'GraphIndexPrefixAdapter',
'InMemoryGraphIndex',
]
from bisect import bisect_right
from cStringIO import StringIO
import re
import sys
from bzrlib.lazy_import import lazy_import
lazy_import(globals(), """
from bzrlib import trace
from bzrlib.bisect_multi import bisect_multi_bytes
from bzrlib.revision import NULL_REVISION
from bzrlib.trace import mutter
""")
from bzrlib import (
debug,
errors,
)
from bzrlib.static_tuple import StaticTuple
_HEADER_READV = (0, 200)
_OPTION_KEY_ELEMENTS = "key_elements="
_OPTION_LEN = "len="
_OPTION_NODE_REFS = "node_ref_lists="
_SIGNATURE = "Bazaar Graph Index 1\n"
_whitespace_re = re.compile('[\t\n\x0b\x0c\r\x00 ]')
_newline_null_re = re.compile('[\n\0]')
def _has_key_from_parent_map(self, key):
"""Check if this index has one key.
If it's possible to check for multiple keys at once through
calling get_parent_map that should be faster.
"""
return (key in self.get_parent_map([key]))
def _missing_keys_from_parent_map(self, keys):
return set(keys) - set(self.get_parent_map(keys))
class GraphIndexBuilder(object):
"""A builder that can build a GraphIndex.
The resulting graph has the structure:
_SIGNATURE OPTIONS NODES NEWLINE
_SIGNATURE := 'Bazaar Graph Index 1' NEWLINE
OPTIONS := 'node_ref_lists=' DIGITS NEWLINE
NODES := NODE*
NODE := KEY NULL ABSENT? NULL REFERENCES NULL VALUE NEWLINE
KEY := Not-whitespace-utf8
ABSENT := 'a'
REFERENCES := REFERENCE_LIST (TAB REFERENCE_LIST){node_ref_lists - 1}
REFERENCE_LIST := (REFERENCE (CR REFERENCE)*)?
REFERENCE := DIGITS ; digits is the byte offset in the index of the
; referenced key.
VALUE := no-newline-no-null-bytes
"""
def __init__(self, reference_lists=0, key_elements=1):
"""Create a GraphIndex builder.
:param reference_lists: The number of node references lists for each
entry.
:param key_elements: The number of bytestrings in each key.
"""
self.reference_lists = reference_lists
# A dict of {key: (absent, ref_lists, value)}
self._nodes = {}
# Keys that are referenced but not actually present in this index
self._absent_keys = set()
self._nodes_by_key = None
self._key_length = key_elements
self._optimize_for_size = False
self._combine_backing_indices = True
def _check_key(self, key):
"""Raise BadIndexKey if key is not a valid key for this index."""
if type(key) not in (tuple, StaticTuple):
raise errors.BadIndexKey(key)
if self._key_length != len(key):
raise errors.BadIndexKey(key)
for element in key:
if not element or _whitespace_re.search(element) is not None:
raise errors.BadIndexKey(element)
def _external_references(self):
"""Return references that are not present in this index.
"""
keys = set()
refs = set()
# TODO: JAM 2008-11-21 This makes an assumption about how the reference
# lists are used. It is currently correct for pack-0.92 through
# 1.9, which use the node references (3rd column) second
# reference list as the compression parent. Perhaps this should
# be moved into something higher up the stack, since it
# makes assumptions about how the index is used.
if self.reference_lists > 1:
for node in self.iter_all_entries():
keys.add(node[1])
refs.update(node[3][1])
return refs - keys
else:
# If reference_lists == 0 there can be no external references, and
# if reference_lists == 1, then there isn't a place to store the
# compression parent
return set()
def _get_nodes_by_key(self):
if self._nodes_by_key is None:
nodes_by_key = {}
if self.reference_lists:
for key, (absent, references, value) in self._nodes.iteritems():
if absent:
continue
key_dict = nodes_by_key
for subkey in key[:-1]:
key_dict = key_dict.setdefault(subkey, {})
key_dict[key[-1]] = key, value, references
else:
for key, (absent, references, value) in self._nodes.iteritems():
if absent:
continue
key_dict = nodes_by_key
for subkey in key[:-1]:
key_dict = key_dict.setdefault(subkey, {})
key_dict[key[-1]] = key, value
self._nodes_by_key = nodes_by_key
return self._nodes_by_key
def _update_nodes_by_key(self, key, value, node_refs):
"""Update the _nodes_by_key dict with a new key.
For a key of (foo, bar, baz) create
_nodes_by_key[foo][bar][baz] = key_value
"""
if self._nodes_by_key is None:
return
key_dict = self._nodes_by_key
if self.reference_lists:
key_value = StaticTuple(key, value, node_refs)
else:
key_value = StaticTuple(key, value)
for subkey in key[:-1]:
key_dict = key_dict.setdefault(subkey, {})
key_dict[key[-1]] = key_value
def _check_key_ref_value(self, key, references, value):
"""Check that 'key' and 'references' are all valid.
:param key: A key tuple. Must conform to the key interface (be a tuple,
be of the right length, not have any whitespace or nulls in any key
element.)
:param references: An iterable of reference lists. Something like
[[(ref, key)], [(ref, key), (other, key)]]
:param value: The value associate with this key. Must not contain
newlines or null characters.
:return: (node_refs, absent_references)
node_refs basically a packed form of 'references' where all
iterables are tuples
absent_references reference keys that are not in self._nodes.
This may contain duplicates if the same key is
referenced in multiple lists.
"""
as_st = StaticTuple.from_sequence
self._check_key(key)
if _newline_null_re.search(value) is not None:
raise errors.BadIndexValue(value)
if len(references) != self.reference_lists:
raise errors.BadIndexValue(references)
node_refs = []
absent_references = []
for reference_list in references:
for reference in reference_list:
# If reference *is* in self._nodes, then we know it has already
# been checked.
if reference not in self._nodes:
self._check_key(reference)
absent_references.append(reference)
reference_list = as_st([as_st(ref).intern()
for ref in reference_list])
node_refs.append(reference_list)
return as_st(node_refs), absent_references
def add_node(self, key, value, references=()):
"""Add a node to the index.
:param key: The key. keys are non-empty tuples containing
as many whitespace-free utf8 bytestrings as the key length
defined for this index.
:param references: An iterable of iterables of keys. Each is a
reference to another key.
:param value: The value to associate with the key. It may be any
bytes as long as it does not contain \0 or \n.
"""
(node_refs,
absent_references) = self._check_key_ref_value(key, references, value)
if key in self._nodes and self._nodes[key][0] != 'a':
raise errors.BadIndexDuplicateKey(key, self)
for reference in absent_references:
# There may be duplicates, but I don't think it is worth worrying
# about
self._nodes[reference] = ('a', (), '')
self._absent_keys.update(absent_references)
self._absent_keys.discard(key)
self._nodes[key] = ('', node_refs, value)
if self._nodes_by_key is not None and self._key_length > 1:
self._update_nodes_by_key(key, value, node_refs)
def clear_cache(self):
"""See GraphIndex.clear_cache()
This is a no-op, but we need the api to conform to a generic 'Index'
abstraction.
"""
def finish(self):
lines = [_SIGNATURE]
lines.append(_OPTION_NODE_REFS + str(self.reference_lists) + '\n')
lines.append(_OPTION_KEY_ELEMENTS + str(self._key_length) + '\n')
key_count = len(self._nodes) - len(self._absent_keys)
lines.append(_OPTION_LEN + str(key_count) + '\n')
prefix_length = sum(len(x) for x in lines)
# references are byte offsets. To avoid having to do nasty
# polynomial work to resolve offsets (references to later in the
# file cannot be determined until all the inbetween references have
# been calculated too) we pad the offsets with 0's to make them be
# of consistent length. Using binary offsets would break the trivial
# file parsing.
# to calculate the width of zero's needed we do three passes:
# one to gather all the non-reference data and the number of references.
# one to pad all the data with reference-length and determine entry
# addresses.
# One to serialise.
# forward sorted by key. In future we may consider topological sorting,
# at the cost of table scans for direct lookup, or a second index for
# direct lookup
nodes = sorted(self._nodes.items())
# if we do not prepass, we don't know how long it will be up front.
expected_bytes = None
# we only need to pre-pass if we have reference lists at all.
if self.reference_lists:
key_offset_info = []
non_ref_bytes = prefix_length
total_references = 0
# TODO use simple multiplication for the constants in this loop.
for key, (absent, references, value) in nodes:
# record the offset known *so far* for this key:
# the non reference bytes to date, and the total references to
# date - saves reaccumulating on the second pass
key_offset_info.append((key, non_ref_bytes, total_references))
# key is literal, value is literal, there are 3 null's, 1 NL
# key is variable length tuple, \x00 between elements
non_ref_bytes += sum(len(element) for element in key)
if self._key_length > 1:
non_ref_bytes += self._key_length - 1
# value is literal bytes, there are 3 null's, 1 NL.
non_ref_bytes += len(value) + 3 + 1
# one byte for absent if set.
if absent:
non_ref_bytes += 1
elif self.reference_lists:
# (ref_lists -1) tabs
non_ref_bytes += self.reference_lists - 1
# (ref-1 cr's per ref_list)
for ref_list in references:
# how many references across the whole file?
total_references += len(ref_list)
# accrue reference separators
if ref_list:
non_ref_bytes += len(ref_list) - 1
# how many digits are needed to represent the total byte count?
digits = 1
possible_total_bytes = non_ref_bytes + total_references*digits
while 10 ** digits < possible_total_bytes:
digits += 1
possible_total_bytes = non_ref_bytes + total_references*digits
expected_bytes = possible_total_bytes + 1 # terminating newline
# resolve key addresses.
key_addresses = {}
for key, non_ref_bytes, total_references in key_offset_info:
key_addresses[key] = non_ref_bytes + total_references*digits
# serialise
format_string = '%%0%sd' % digits
for key, (absent, references, value) in nodes:
flattened_references = []
for ref_list in references:
ref_addresses = []
for reference in ref_list:
ref_addresses.append(format_string % key_addresses[reference])
flattened_references.append('\r'.join(ref_addresses))
string_key = '\x00'.join(key)
lines.append("%s\x00%s\x00%s\x00%s\n" % (string_key, absent,
'\t'.join(flattened_references), value))
lines.append('\n')
result = StringIO(''.join(lines))
if expected_bytes and len(result.getvalue()) != expected_bytes:
raise errors.BzrError('Failed index creation. Internal error:'
' mismatched output length and expected length: %d %d' %
(len(result.getvalue()), expected_bytes))
return result
def set_optimize(self, for_size=None, combine_backing_indices=None):
"""Change how the builder tries to optimize the result.
:param for_size: Tell the builder to try and make the index as small as
possible.
:param combine_backing_indices: If the builder spills to disk to save
memory, should the on-disk indices be combined. Set to True if you
are going to be probing the index, but to False if you are not. (If
you are not querying, then the time spent combining is wasted.)
:return: None
"""
# GraphIndexBuilder itself doesn't pay attention to the flag yet, but
# other builders do.
if for_size is not None:
self._optimize_for_size = for_size
if combine_backing_indices is not None:
self._combine_backing_indices = combine_backing_indices
def find_ancestry(self, keys, ref_list_num):
"""See CombinedGraphIndex.find_ancestry()"""
pending = set(keys)
parent_map = {}
missing_keys = set()
while pending:
next_pending = set()
for _, key, value, ref_lists in self.iter_entries(pending):
parent_keys = ref_lists[ref_list_num]
parent_map[key] = parent_keys
next_pending.update([p for p in parent_keys if p not in
parent_map])
missing_keys.update(pending.difference(parent_map))
pending = next_pending
return parent_map, missing_keys
class GraphIndex(object):
"""An index for data with embedded graphs.
The index maps keys to a list of key reference lists, and a value.
Each node has the same number of key reference lists. Each key reference
list can be empty or an arbitrary length. The value is an opaque NULL
terminated string without any newlines. The storage of the index is
hidden in the interface: keys and key references are always tuples of
bytestrings, never the internal representation (e.g. dictionary offsets).
It is presumed that the index will not be mutated - it is static data.
Successive iter_all_entries calls will read the entire index each time.
Additionally, iter_entries calls will read the index linearly until the
desired keys are found. XXX: This must be fixed before the index is
suitable for production use. :XXX
"""
def __init__(self, transport, name, size, unlimited_cache=False, offset=0):
"""Open an index called name on transport.
:param transport: A bzrlib.transport.Transport.
:param name: A path to provide to transport API calls.
:param size: The size of the index in bytes. This is used for bisection
logic to perform partial index reads. While the size could be
obtained by statting the file this introduced an additional round
trip as well as requiring stat'able transports, both of which are
avoided by having it supplied. If size is None, then bisection
support will be disabled and accessing the index will just stream
all the data.
:param offset: Instead of starting the index data at offset 0, start it
at an arbitrary offset.
"""
self._transport = transport
self._name = name
# Becomes a dict of key:(value, reference-list-byte-locations) used by
# the bisection interface to store parsed but not resolved keys.
self._bisect_nodes = None
# Becomes a dict of key:(value, reference-list-keys) which are ready to
# be returned directly to callers.
self._nodes = None
# a sorted list of slice-addresses for the parsed bytes of the file.
# e.g. (0,1) would mean that byte 0 is parsed.
self._parsed_byte_map = []
# a sorted list of keys matching each slice address for parsed bytes
# e.g. (None, 'foo@bar') would mean that the first byte contained no
# key, and the end byte of the slice is the of the data for 'foo@bar'
self._parsed_key_map = []
self._key_count = None
self._keys_by_offset = None
self._nodes_by_key = None
self._size = size
# The number of bytes we've read so far in trying to process this file
self._bytes_read = 0
self._base_offset = offset
def __eq__(self, other):
"""Equal when self and other were created with the same parameters."""
return (
type(self) == type(other) and
self._transport == other._transport and
self._name == other._name and
self._size == other._size)
def __ne__(self, other):
return not self.__eq__(other)
def __repr__(self):
return "%s(%r)" % (self.__class__.__name__,
self._transport.abspath(self._name))
def _buffer_all(self, stream=None):
"""Buffer all the index data.
Mutates self._nodes and self.keys_by_offset.
"""
if self._nodes is not None:
# We already did this
return
if 'index' in debug.debug_flags:
mutter('Reading entire index %s', self._transport.abspath(self._name))
if stream is None:
stream = self._transport.get(self._name)
if self._base_offset != 0:
# This is wasteful, but it is better than dealing with
# adjusting all the offsets, etc.
stream = StringIO(stream.read()[self._base_offset:])
self._read_prefix(stream)
self._expected_elements = 3 + self._key_length
line_count = 0
# raw data keyed by offset
self._keys_by_offset = {}
# ready-to-return key:value or key:value, node_ref_lists
self._nodes = {}
self._nodes_by_key = None
trailers = 0
pos = stream.tell()
lines = stream.read().split('\n')
# GZ 2009-09-20: Should really use a try/finally block to ensure close
stream.close()
del lines[-1]
_, _, _, trailers = self._parse_lines(lines, pos)
for key, absent, references, value in self._keys_by_offset.itervalues():
if absent:
continue
# resolve references:
if self.node_ref_lists:
node_value = (value, self._resolve_references(references))
else:
node_value = value
self._nodes[key] = node_value
# cache the keys for quick set intersections
if trailers != 1:
# there must be one line - the empty trailer line.
raise errors.BadIndexData(self)
def clear_cache(self):
"""Clear out any cached/memoized values.
This can be called at any time, but generally it is used when we have
extracted some information, but don't expect to be requesting any more
from this index.
"""
def external_references(self, ref_list_num):
"""Return references that are not present in this index.
"""
self._buffer_all()
if ref_list_num + 1 > self.node_ref_lists:
raise ValueError('No ref list %d, index has %d ref lists'
% (ref_list_num, self.node_ref_lists))
refs = set()
nodes = self._nodes
for key, (value, ref_lists) in nodes.iteritems():
ref_list = ref_lists[ref_list_num]
refs.update([ref for ref in ref_list if ref not in nodes])
return refs
def _get_nodes_by_key(self):
if self._nodes_by_key is None:
nodes_by_key = {}
if self.node_ref_lists:
for key, (value, references) in self._nodes.iteritems():
key_dict = nodes_by_key
for subkey in key[:-1]:
key_dict = key_dict.setdefault(subkey, {})
key_dict[key[-1]] = key, value, references
else:
for key, value in self._nodes.iteritems():
key_dict = nodes_by_key
for subkey in key[:-1]:
key_dict = key_dict.setdefault(subkey, {})
key_dict[key[-1]] = key, value
self._nodes_by_key = nodes_by_key
return self._nodes_by_key
def iter_all_entries(self):
"""Iterate over all keys within the index.
:return: An iterable of (index, key, value) or (index, key, value, reference_lists).
The former tuple is used when there are no reference lists in the
index, making the API compatible with simple key:value index types.
There is no defined order for the result iteration - it will be in
the most efficient order for the index.
"""
if 'evil' in debug.debug_flags:
trace.mutter_callsite(3,
"iter_all_entries scales with size of history.")
if self._nodes is None:
self._buffer_all()
if self.node_ref_lists:
for key, (value, node_ref_lists) in self._nodes.iteritems():
yield self, key, value, node_ref_lists
else:
for key, value in self._nodes.iteritems():
yield self, key, value
def _read_prefix(self, stream):
signature = stream.read(len(self._signature()))
if not signature == self._signature():
raise errors.BadIndexFormatSignature(self._name, GraphIndex)
options_line = stream.readline()
if not options_line.startswith(_OPTION_NODE_REFS):
raise errors.BadIndexOptions(self)
try:
self.node_ref_lists = int(options_line[len(_OPTION_NODE_REFS):-1])
except ValueError:
raise errors.BadIndexOptions(self)
options_line = stream.readline()
if not options_line.startswith(_OPTION_KEY_ELEMENTS):
raise errors.BadIndexOptions(self)
try:
self._key_length = int(options_line[len(_OPTION_KEY_ELEMENTS):-1])
except ValueError:
raise errors.BadIndexOptions(self)
options_line = stream.readline()
if not options_line.startswith(_OPTION_LEN):
raise errors.BadIndexOptions(self)
try:
self._key_count = int(options_line[len(_OPTION_LEN):-1])
except ValueError:
raise errors.BadIndexOptions(self)
def _resolve_references(self, references):
"""Return the resolved key references for references.
References are resolved by looking up the location of the key in the
_keys_by_offset map and substituting the key name, preserving ordering.
:param references: An iterable of iterables of key locations. e.g.
[[123, 456], [123]]
:return: A tuple of tuples of keys.
"""
node_refs = []
for ref_list in references:
node_refs.append(tuple([self._keys_by_offset[ref][0] for ref in ref_list]))
return tuple(node_refs)
def _find_index(self, range_map, key):
"""Helper for the _parsed_*_index calls.
Given a range map - [(start, end), ...], finds the index of the range
in the map for key if it is in the map, and if it is not there, the
immediately preceeding range in the map.
"""
result = bisect_right(range_map, key) - 1
if result + 1 < len(range_map):
# check the border condition, it may be in result + 1
if range_map[result + 1][0] == key[0]:
return result + 1
return result
def _parsed_byte_index(self, offset):
"""Return the index of the entry immediately before offset.
e.g. if the parsed map has regions 0,10 and 11,12 parsed, meaning that
there is one unparsed byte (the 11th, addressed as[10]). then:
asking for 0 will return 0
asking for 10 will return 0
asking for 11 will return 1
asking for 12 will return 1
"""
key = (offset, 0)
return self._find_index(self._parsed_byte_map, key)
def _parsed_key_index(self, key):
"""Return the index of the entry immediately before key.
e.g. if the parsed map has regions (None, 'a') and ('b','c') parsed,
meaning that keys from None to 'a' inclusive, and 'b' to 'c' inclusive
have been parsed, then:
asking for '' will return 0
asking for 'a' will return 0
asking for 'b' will return 1
asking for 'e' will return 1
"""
search_key = (key, None)
return self._find_index(self._parsed_key_map, search_key)
def _is_parsed(self, offset):
"""Returns True if offset has been parsed."""
index = self._parsed_byte_index(offset)
if index == len(self._parsed_byte_map):
return offset < self._parsed_byte_map[index - 1][1]
start, end = self._parsed_byte_map[index]
return offset >= start and offset < end
def _iter_entries_from_total_buffer(self, keys):
"""Iterate over keys when the entire index is parsed."""
# Note: See the note in BTreeBuilder.iter_entries for why we don't use
# .intersection() here
nodes = self._nodes
keys = [key for key in keys if key in nodes]
if self.node_ref_lists:
for key in keys:
value, node_refs = nodes[key]
yield self, key, value, node_refs
else:
for key in keys:
yield self, key, nodes[key]
def iter_entries(self, keys):
"""Iterate over keys within the index.
:param keys: An iterable providing the keys to be retrieved.
:return: An iterable as per iter_all_entries, but restricted to the
keys supplied. No additional keys will be returned, and every
key supplied that is in the index will be returned.
"""
keys = set(keys)
if not keys:
return []
if self._size is None and self._nodes is None:
self._buffer_all()
# We fit about 20 keys per minimum-read (4K), so if we are looking for
# more than 1/20th of the index its likely (assuming homogenous key
# spread) that we'll read the entire index. If we're going to do that,
# buffer the whole thing. A better analysis might take key spread into
# account - but B+Tree indices are better anyway.
# We could look at all data read, and use a threshold there, which will
# trigger on ancestry walks, but that is not yet fully mapped out.
if self._nodes is None and len(keys) * 20 > self.key_count():
self._buffer_all()
if self._nodes is not None:
return self._iter_entries_from_total_buffer(keys)
else:
return (result[1] for result in bisect_multi_bytes(
self._lookup_keys_via_location, self._size, keys))
def iter_entries_prefix(self, keys):
"""Iterate over keys within the index using prefix matching.
Prefix matching is applied within the tuple of a key, not to within
the bytestring of each key element. e.g. if you have the keys ('foo',
'bar'), ('foobar', 'gam') and do a prefix search for ('foo', None) then
only the former key is returned.
WARNING: Note that this method currently causes a full index parse
unconditionally (which is reasonably appropriate as it is a means for
thunking many small indices into one larger one and still supplies
iter_all_entries at the thunk layer).
:param keys: An iterable providing the key prefixes to be retrieved.
Each key prefix takes the form of a tuple the length of a key, but
with the last N elements 'None' rather than a regular bytestring.
The first element cannot be 'None'.
:return: An iterable as per iter_all_entries, but restricted to the
keys with a matching prefix to those supplied. No additional keys
will be returned, and every match that is in the index will be
returned.
"""
keys = set(keys)
if not keys:
return
# load data - also finds key lengths
if self._nodes is None:
self._buffer_all()
if self._key_length == 1:
for key in keys:
# sanity check
if key[0] is None:
raise errors.BadIndexKey(key)
if len(key) != self._key_length:
raise errors.BadIndexKey(key)
if self.node_ref_lists:
value, node_refs = self._nodes[key]
yield self, key, value, node_refs
else:
yield self, key, self._nodes[key]
return
nodes_by_key = self._get_nodes_by_key()
for key in keys:
# sanity check
if key[0] is None:
raise errors.BadIndexKey(key)
if len(key) != self._key_length:
raise errors.BadIndexKey(key)
# find what it refers to:
key_dict = nodes_by_key
elements = list(key)
# find the subdict whose contents should be returned.
try:
while len(elements) and elements[0] is not None:
key_dict = key_dict[elements[0]]
elements.pop(0)
except KeyError:
# a non-existant lookup.
continue
if len(elements):
dicts = [key_dict]
while dicts:
key_dict = dicts.pop(-1)
# can't be empty or would not exist
item, value = key_dict.iteritems().next()
if type(value) == dict:
# push keys
dicts.extend(key_dict.itervalues())
else:
# yield keys
for value in key_dict.itervalues():
# each value is the key:value:node refs tuple
# ready to yield.
yield (self, ) + value
else:
# the last thing looked up was a terminal element
yield (self, ) + key_dict
def _find_ancestors(self, keys, ref_list_num, parent_map, missing_keys):
"""See BTreeIndex._find_ancestors."""
# The api can be implemented as a trivial overlay on top of
# iter_entries, it is not an efficient implementation, but it at least
# gets the job done.
found_keys = set()
search_keys = set()
for index, key, value, refs in self.iter_entries(keys):
parent_keys = refs[ref_list_num]
found_keys.add(key)
parent_map[key] = parent_keys
search_keys.update(parent_keys)
# Figure out what, if anything, was missing
missing_keys.update(set(keys).difference(found_keys))
search_keys = search_keys.difference(parent_map)
return search_keys
def key_count(self):
"""Return an estimate of the number of keys in this index.
For GraphIndex the estimate is exact.
"""
if self._key_count is None:
self._read_and_parse([_HEADER_READV])
return self._key_count
def _lookup_keys_via_location(self, location_keys):
"""Public interface for implementing bisection.
If _buffer_all has been called, then all the data for the index is in
memory, and this method should not be called, as it uses a separate
cache because it cannot pre-resolve all indices, which buffer_all does
for performance.
:param location_keys: A list of location(byte offset), key tuples.
:return: A list of (location_key, result) tuples as expected by
bzrlib.bisect_multi.bisect_multi_bytes.
"""
# Possible improvements:
# - only bisect lookup each key once
# - sort the keys first, and use that to reduce the bisection window
# -----
# this progresses in three parts:
# read data
# parse it
# attempt to answer the question from the now in memory data.
# build the readv request
# for each location, ask for 800 bytes - much more than rows we've seen
# anywhere.
readv_ranges = []
for location, key in location_keys:
# can we answer from cache?
if self._bisect_nodes and key in self._bisect_nodes:
# We have the key parsed.
continue
index = self._parsed_key_index(key)
if (len(self._parsed_key_map) and
self._parsed_key_map[index][0] <= key and
(self._parsed_key_map[index][1] >= key or
# end of the file has been parsed
self._parsed_byte_map[index][1] == self._size)):
# the key has been parsed, so no lookup is needed even if its
# not present.
continue
# - if we have examined this part of the file already - yes
index = self._parsed_byte_index(location)
if (len(self._parsed_byte_map) and
self._parsed_byte_map[index][0] <= location and
self._parsed_byte_map[index][1] > location):
# the byte region has been parsed, so no read is needed.
continue
length = 800
if location + length > self._size:
length = self._size - location
# todo, trim out parsed locations.
if length > 0:
readv_ranges.append((location, length))
# read the header if needed
if self._bisect_nodes is None:
readv_ranges.append(_HEADER_READV)
self._read_and_parse(readv_ranges)
result = []
if self._nodes is not None:
# _read_and_parse triggered a _buffer_all because we requested the
# whole data range
for location, key in location_keys:
if key not in self._nodes: # not present
result.append(((location, key), False))
elif self.node_ref_lists:
value, refs = self._nodes[key]
result.append(((location, key),
(self, key, value, refs)))
else:
result.append(((location, key),
(self, key, self._nodes[key])))
return result
# generate results:
# - figure out <, >, missing, present
# - result present references so we can return them.
# keys that we cannot answer until we resolve references
pending_references = []
pending_locations = set()
for location, key in location_keys:
# can we answer from cache?
if key in self._bisect_nodes:
# the key has been parsed, so no lookup is needed
if self.node_ref_lists:
# the references may not have been all parsed.
value, refs = self._bisect_nodes[key]
wanted_locations = []
for ref_list in refs:
for ref in ref_list:
if ref not in self._keys_by_offset:
wanted_locations.append(ref)
if wanted_locations:
pending_locations.update(wanted_locations)
pending_references.append((location, key))
continue
result.append(((location, key), (self, key,
value, self._resolve_references(refs))))
else:
result.append(((location, key),
(self, key, self._bisect_nodes[key])))
continue
else:
# has the region the key should be in, been parsed?
index = self._parsed_key_index(key)
if (self._parsed_key_map[index][0] <= key and
(self._parsed_key_map[index][1] >= key or
# end of the file has been parsed
self._parsed_byte_map[index][1] == self._size)):
result.append(((location, key), False))
continue
# no, is the key above or below the probed location:
# get the range of the probed & parsed location
index = self._parsed_byte_index(location)
# if the key is below the start of the range, its below
if key < self._parsed_key_map[index][0]:
direction = -1
else:
direction = +1
result.append(((location, key), direction))
readv_ranges = []
# lookup data to resolve references
for location in pending_locations:
length = 800
if location + length > self._size:
length = self._size - location
# TODO: trim out parsed locations (e.g. if the 800 is into the
# parsed region trim it, and dont use the adjust_for_latency
# facility)
if length > 0:
readv_ranges.append((location, length))
self._read_and_parse(readv_ranges)
if self._nodes is not None:
# The _read_and_parse triggered a _buffer_all, grab the data and
# return it
for location, key in pending_references:
value, refs = self._nodes[key]
result.append(((location, key), (self, key, value, refs)))
return result
for location, key in pending_references:
# answer key references we had to look-up-late.
value, refs = self._bisect_nodes[key]
result.append(((location, key), (self, key,
value, self._resolve_references(refs))))
return result
def _parse_header_from_bytes(self, bytes):
"""Parse the header from a region of bytes.
:param bytes: The data to parse.
:return: An offset, data tuple such as readv yields, for the unparsed
data. (which may length 0).
"""
signature = bytes[0:len(self._signature())]
if not signature == self._signature():
raise errors.BadIndexFormatSignature(self._name, GraphIndex)
lines = bytes[len(self._signature()):].splitlines()
options_line = lines[0]
if not options_line.startswith(_OPTION_NODE_REFS):
raise errors.BadIndexOptions(self)
try:
self.node_ref_lists = int(options_line[len(_OPTION_NODE_REFS):])
except ValueError:
raise errors.BadIndexOptions(self)
options_line = lines[1]
if not options_line.startswith(_OPTION_KEY_ELEMENTS):
raise errors.BadIndexOptions(self)
try:
self._key_length = int(options_line[len(_OPTION_KEY_ELEMENTS):])
except ValueError:
raise errors.BadIndexOptions(self)
options_line = lines[2]
if not options_line.startswith(_OPTION_LEN):
raise errors.BadIndexOptions(self)
try:
self._key_count = int(options_line[len(_OPTION_LEN):])
except ValueError:
raise errors.BadIndexOptions(self)
# calculate the bytes we have processed
header_end = (len(signature) + len(lines[0]) + len(lines[1]) +
len(lines[2]) + 3)
self._parsed_bytes(0, None, header_end, None)
# setup parsing state
self._expected_elements = 3 + self._key_length
# raw data keyed by offset
self._keys_by_offset = {}
# keys with the value and node references
self._bisect_nodes = {}
return header_end, bytes[header_end:]
def _parse_region(self, offset, data):
"""Parse node data returned from a readv operation.
:param offset: The byte offset the data starts at.
:param data: The data to parse.
"""
# trim the data.
# end first:
end = offset + len(data)
high_parsed = offset
while True:
# Trivial test - if the current index's end is within the
# low-matching parsed range, we're done.
index = self._parsed_byte_index(high_parsed)
if end < self._parsed_byte_map[index][1]:
return
# print "[%d:%d]" % (offset, end), \
# self._parsed_byte_map[index:index + 2]
high_parsed, last_segment = self._parse_segment(
offset, data, end, index)
if last_segment:
return
def _parse_segment(self, offset, data, end, index):
"""Parse one segment of data.
:param offset: Where 'data' begins in the file.
:param data: Some data to parse a segment of.
:param end: Where data ends
:param index: The current index into the parsed bytes map.
:return: True if the parsed segment is the last possible one in the
range of data.
:return: high_parsed_byte, last_segment.
high_parsed_byte is the location of the highest parsed byte in this
segment, last_segment is True if the parsed segment is the last
possible one in the data block.
"""
# default is to use all data
trim_end = None
# accomodate overlap with data before this.
if offset < self._parsed_byte_map[index][1]:
# overlaps the lower parsed region
# skip the parsed data
trim_start = self._parsed_byte_map[index][1] - offset
# don't trim the start for \n
start_adjacent = True
elif offset == self._parsed_byte_map[index][1]:
# abuts the lower parsed region
# use all data
trim_start = None
# do not trim anything
start_adjacent = True
else:
# does not overlap the lower parsed region
# use all data
trim_start = None
# but trim the leading \n
start_adjacent = False
if end == self._size:
# lines up to the end of all data:
# use it all
trim_end = None
# do not strip to the last \n
end_adjacent = True
last_segment = True
elif index + 1 == len(self._parsed_byte_map):
# at the end of the parsed data
# use it all
trim_end = None
# but strip to the last \n
end_adjacent = False
last_segment = True
elif end == self._parsed_byte_map[index + 1][0]:
# buts up against the next parsed region
# use it all
trim_end = None
# do not strip to the last \n
end_adjacent = True
last_segment = True
elif end > self._parsed_byte_map[index + 1][0]:
# overlaps into the next parsed region
# only consider the unparsed data
trim_end = self._parsed_byte_map[index + 1][0] - offset
# do not strip to the last \n as we know its an entire record
end_adjacent = True
last_segment = end < self._parsed_byte_map[index + 1][1]
else:
# does not overlap into the next region
# use it all
trim_end = None
# but strip to the last \n
end_adjacent = False
last_segment = True
# now find bytes to discard if needed
if not start_adjacent:
# work around python bug in rfind
if trim_start is None:
trim_start = data.find('\n') + 1
else:
trim_start = data.find('\n', trim_start) + 1
if not (trim_start != 0):
raise AssertionError('no \n was present')
# print 'removing start', offset, trim_start, repr(data[:trim_start])
if not end_adjacent:
# work around python bug in rfind
if trim_end is None:
trim_end = data.rfind('\n') + 1
else:
trim_end = data.rfind('\n', None, trim_end) + 1
if not (trim_end != 0):
raise AssertionError('no \n was present')
# print 'removing end', offset, trim_end, repr(data[trim_end:])
# adjust offset and data to the parseable data.
trimmed_data = data[trim_start:trim_end]
if not (trimmed_data):
raise AssertionError('read unneeded data [%d:%d] from [%d:%d]'
% (trim_start, trim_end, offset, offset + len(data)))
if trim_start:
offset += trim_start
# print "parsing", repr(trimmed_data)
# splitlines mangles the \r delimiters.. don't use it.
lines = trimmed_data.split('\n')
del lines[-1]
pos = offset
first_key, last_key, nodes, _ = self._parse_lines(lines, pos)
for key, value in nodes:
self._bisect_nodes[key] = value
self._parsed_bytes(offset, first_key,
offset + len(trimmed_data), last_key)
return offset + len(trimmed_data), last_segment
def _parse_lines(self, lines, pos):
key = None
first_key = None
trailers = 0
nodes = []
for line in lines:
if line == '':
# must be at the end
if self._size:
if not (self._size == pos + 1):
raise AssertionError("%s %s" % (self._size, pos))
trailers += 1
continue
elements = line.split('\0')
if len(elements) != self._expected_elements:
raise errors.BadIndexData(self)
# keys are tuples. Each element is a string that may occur many
# times, so we intern them to save space. AB, RC, 200807
key = tuple([intern(element) for element in elements[:self._key_length]])
if first_key is None:
first_key = key
absent, references, value = elements[-3:]
ref_lists = []
for ref_string in references.split('\t'):
ref_lists.append(tuple([
int(ref) for ref in ref_string.split('\r') if ref
]))
ref_lists = tuple(ref_lists)
self._keys_by_offset[pos] = (key, absent, ref_lists, value)
pos += len(line) + 1 # +1 for the \n
if absent:
continue
if self.node_ref_lists:
node_value = (value, ref_lists)
else:
node_value = value
nodes.append((key, node_value))
# print "parsed ", key
return first_key, key, nodes, trailers
def _parsed_bytes(self, start, start_key, end, end_key):
"""Mark the bytes from start to end as parsed.
Calling self._parsed_bytes(1,2) will mark one byte (the one at offset
1) as parsed.
:param start: The start of the parsed region.
:param end: The end of the parsed region.
"""
index = self._parsed_byte_index(start)
new_value = (start, end)
new_key = (start_key, end_key)
if index == -1:
# first range parsed is always the beginning.
self._parsed_byte_map.insert(index, new_value)
self._parsed_key_map.insert(index, new_key)
return
# four cases:
# new region
# extend lower region
# extend higher region
# combine two regions
if (index + 1 < len(self._parsed_byte_map) and
self._parsed_byte_map[index][1] == start and
self._parsed_byte_map[index + 1][0] == end):
# combine two regions
self._parsed_byte_map[index] = (self._parsed_byte_map[index][0],
self._parsed_byte_map[index + 1][1])
self._parsed_key_map[index] = (self._parsed_key_map[index][0],
self._parsed_key_map[index + 1][1])
del self._parsed_byte_map[index + 1]
del self._parsed_key_map[index + 1]
elif self._parsed_byte_map[index][1] == start:
# extend the lower entry
self._parsed_byte_map[index] = (
self._parsed_byte_map[index][0], end)
self._parsed_key_map[index] = (
self._parsed_key_map[index][0], end_key)
elif (index + 1 < len(self._parsed_byte_map) and
self._parsed_byte_map[index + 1][0] == end):
# extend the higher entry
self._parsed_byte_map[index + 1] = (
start, self._parsed_byte_map[index + 1][1])
self._parsed_key_map[index + 1] = (
start_key, self._parsed_key_map[index + 1][1])
else:
# new entry
self._parsed_byte_map.insert(index + 1, new_value)
self._parsed_key_map.insert(index + 1, new_key)
def _read_and_parse(self, readv_ranges):
"""Read the ranges and parse the resulting data.
:param readv_ranges: A prepared readv range list.
"""
if not readv_ranges:
return
if self._nodes is None and self._bytes_read * 2 >= self._size:
# We've already read more than 50% of the file and we are about to
# request more data, just _buffer_all() and be done
self._buffer_all()
return
base_offset = self._base_offset
if base_offset != 0:
# Rewrite the ranges for the offset
readv_ranges = [(start+base_offset, size)
for start, size in readv_ranges]
readv_data = self._transport.readv(self._name, readv_ranges, True,
self._size + self._base_offset)
# parse
for offset, data in readv_data:
offset -= base_offset
self._bytes_read += len(data)
if offset < 0:
# transport.readv() expanded to extra data which isn't part of
# this index
data = data[-offset:]
offset = 0
if offset == 0 and len(data) == self._size:
# We read the whole range, most likely because the
# Transport upcast our readv ranges into one long request
# for enough total data to grab the whole index.
self._buffer_all(StringIO(data))
return
if self._bisect_nodes is None:
# this must be the start
if not (offset == 0):
raise AssertionError()
offset, data = self._parse_header_from_bytes(data)
# print readv_ranges, "[%d:%d]" % (offset, offset + len(data))
self._parse_region(offset, data)
def _signature(self):
"""The file signature for this index type."""
return _SIGNATURE
def validate(self):
"""Validate that everything in the index can be accessed."""
# iter_all validates completely at the moment, so just do that.
for node in self.iter_all_entries():
pass
class CombinedGraphIndex(object):
"""A GraphIndex made up from smaller GraphIndices.
The backing indices must implement GraphIndex, and are presumed to be
static data.
Queries against the combined index will be made against the first index,
and then the second and so on. The order of indices can thus influence
performance significantly. For example, if one index is on local disk and a
second on a remote server, the local disk index should be before the other
in the index list.
Also, queries tend to need results from the same indices as previous
queries. So the indices will be reordered after every query to put the
indices that had the result(s) of that query first (while otherwise
preserving the relative ordering).
"""
def __init__(self, indices, reload_func=None):
"""Create a CombinedGraphIndex backed by indices.
:param indices: An ordered list of indices to query for data.
:param reload_func: A function to call if we find we are missing an
index. Should have the form reload_func() => True/False to indicate
if reloading actually changed anything.
"""
self._indices = indices
self._reload_func = reload_func
# Sibling indices are other CombinedGraphIndex that we should call
# _move_to_front_by_name on when we auto-reorder ourself.
self._sibling_indices = []
# A list of names that corresponds to the instances in self._indices,
# so _index_names[0] is always the name for _indices[0], etc. Sibling
# indices must all use the same set of names as each other.
self._index_names = [None] * len(self._indices)
def __repr__(self):
return "%s(%s)" % (
self.__class__.__name__,
', '.join(map(repr, self._indices)))
def clear_cache(self):
"""See GraphIndex.clear_cache()"""
for index in self._indices:
index.clear_cache()
def get_parent_map(self, keys):
"""See graph.StackedParentsProvider.get_parent_map"""
search_keys = set(keys)
if NULL_REVISION in search_keys:
search_keys.discard(NULL_REVISION)
found_parents = {NULL_REVISION:[]}
else:
found_parents = {}
for index, key, value, refs in self.iter_entries(search_keys):
parents = refs[0]
if not parents:
parents = (NULL_REVISION,)
found_parents[key] = parents
return found_parents
has_key = _has_key_from_parent_map
def insert_index(self, pos, index, name=None):
"""Insert a new index in the list of indices to query.
:param pos: The position to insert the index.
:param index: The index to insert.
:param name: a name for this index, e.g. a pack name. These names can
be used to reflect index reorderings to related CombinedGraphIndex
instances that use the same names. (see set_sibling_indices)
"""
self._indices.insert(pos, index)
self._index_names.insert(pos, name)
def iter_all_entries(self):
"""Iterate over all keys within the index
Duplicate keys across child indices are presumed to have the same
value and are only reported once.
:return: An iterable of (index, key, reference_lists, value).
There is no defined order for the result iteration - it will be in
the most efficient order for the index.
"""
seen_keys = set()
while True:
try:
for index in self._indices:
for node in index.iter_all_entries():
if node[1] not in seen_keys:
yield node
seen_keys.add(node[1])
return
except errors.NoSuchFile:
self._reload_or_raise()
def iter_entries(self, keys):
"""Iterate over keys within the index.
Duplicate keys across child indices are presumed to have the same
value and are only reported once.
:param keys: An iterable providing the keys to be retrieved.
:return: An iterable of (index, key, reference_lists, value). There is
no defined order for the result iteration - it will be in the most
efficient order for the index.
"""
keys = set(keys)
hit_indices = []
while True:
try:
for index in self._indices:
if not keys:
break
index_hit = False
for node in index.iter_entries(keys):
keys.remove(node[1])
yield node
index_hit = True
if index_hit:
hit_indices.append(index)
break
except errors.NoSuchFile:
self._reload_or_raise()
self._move_to_front(hit_indices)
def iter_entries_prefix(self, keys):
"""Iterate over keys within the index using prefix matching.
Duplicate keys across child indices are presumed to have the same
value and are only reported once.
Prefix matching is applied within the tuple of a key, not to within
the bytestring of each key element. e.g. if you have the keys ('foo',
'bar'), ('foobar', 'gam') and do a prefix search for ('foo', None) then
only the former key is returned.
:param keys: An iterable providing the key prefixes to be retrieved.
Each key prefix takes the form of a tuple the length of a key, but
with the last N elements 'None' rather than a regular bytestring.
The first element cannot be 'None'.
:return: An iterable as per iter_all_entries, but restricted to the
keys with a matching prefix to those supplied. No additional keys
will be returned, and every match that is in the index will be
returned.
"""
keys = set(keys)
if not keys:
return
seen_keys = set()
hit_indices = []
while True:
try:
for index in self._indices:
index_hit = False
for node in index.iter_entries_prefix(keys):
if node[1] in seen_keys:
continue
seen_keys.add(node[1])
yield node
index_hit = True
if index_hit:
hit_indices.append(index)
break
except errors.NoSuchFile:
self._reload_or_raise()
self._move_to_front(hit_indices)
def _move_to_front(self, hit_indices):
"""Rearrange self._indices so that hit_indices are first.
Order is maintained as much as possible, e.g. the first unhit index
will be the first index in _indices after the hit_indices, and the
hit_indices will be present in exactly the order they are passed to
_move_to_front.
_move_to_front propagates to all objects in self._sibling_indices by
calling _move_to_front_by_name.
"""
if self._indices[:len(hit_indices)] == hit_indices:
# The 'hit_indices' are already at the front (and in the same
# order), no need to re-order
return
hit_names = self._move_to_front_by_index(hit_indices)
for sibling_idx in self._sibling_indices:
sibling_idx._move_to_front_by_name(hit_names)
def _move_to_front_by_index(self, hit_indices):
"""Core logic for _move_to_front.
Returns a list of names corresponding to the hit_indices param.
"""
indices_info = zip(self._index_names, self._indices)
if 'index' in debug.debug_flags:
mutter('CombinedGraphIndex reordering: currently %r, promoting %r',
indices_info, hit_indices)
hit_names = []
unhit_names = []
new_hit_indices = []
unhit_indices = []
for offset, (name, idx) in enumerate(indices_info):
if idx in hit_indices:
hit_names.append(name)
new_hit_indices.append(idx)
if len(new_hit_indices) == len(hit_indices):
# We've found all of the hit entries, everything else is
# unhit
unhit_names.extend(self._index_names[offset+1:])
unhit_indices.extend(self._indices[offset+1:])
break
else:
unhit_names.append(name)
unhit_indices.append(idx)
self._indices = new_hit_indices + unhit_indices
self._index_names = hit_names + unhit_names
if 'index' in debug.debug_flags:
mutter('CombinedGraphIndex reordered: %r', self._indices)
return hit_names
def _move_to_front_by_name(self, hit_names):
"""Moves indices named by 'hit_names' to front of the search order, as
described in _move_to_front.
"""
# Translate names to index instances, and then call
# _move_to_front_by_index.
indices_info = zip(self._index_names, self._indices)
hit_indices = []
for name, idx in indices_info:
if name in hit_names:
hit_indices.append(idx)
self._move_to_front_by_index(hit_indices)
def find_ancestry(self, keys, ref_list_num):
"""Find the complete ancestry for the given set of keys.
Note that this is a whole-ancestry request, so it should be used
sparingly.
:param keys: An iterable of keys to look for
:param ref_list_num: The reference list which references the parents
we care about.
:return: (parent_map, missing_keys)
"""
# XXX: make this call _move_to_front?
missing_keys = set()
parent_map = {}
keys_to_lookup = set(keys)
generation = 0
while keys_to_lookup:
# keys that *all* indexes claim are missing, stop searching them
generation += 1
all_index_missing = None
# print 'gen\tidx\tsub\tn_keys\tn_pmap\tn_miss'
# print '%4d\t\t\t%4d\t%5d\t%5d' % (generation, len(keys_to_lookup),
# len(parent_map),
# len(missing_keys))
for index_idx, index in enumerate(self._indices):
# TODO: we should probably be doing something with
# 'missing_keys' since we've already determined that
# those revisions have not been found anywhere
index_missing_keys = set()
# Find all of the ancestry we can from this index
# keep looking until the search_keys set is empty, which means
# things we didn't find should be in index_missing_keys
search_keys = keys_to_lookup
sub_generation = 0
# print ' \t%2d\t\t%4d\t%5d\t%5d' % (
# index_idx, len(search_keys),
# len(parent_map), len(index_missing_keys))
while search_keys:
sub_generation += 1
# TODO: ref_list_num should really be a parameter, since
# CombinedGraphIndex does not know what the ref lists
# mean.
search_keys = index._find_ancestors(search_keys,
ref_list_num, parent_map, index_missing_keys)
# print ' \t \t%2d\t%4d\t%5d\t%5d' % (
# sub_generation, len(search_keys),
# len(parent_map), len(index_missing_keys))
# Now set whatever was missing to be searched in the next index
keys_to_lookup = index_missing_keys
if all_index_missing is None:
all_index_missing = set(index_missing_keys)
else:
all_index_missing.intersection_update(index_missing_keys)
if not keys_to_lookup:
break
if all_index_missing is None:
# There were no indexes, so all search keys are 'missing'
missing_keys.update(keys_to_lookup)
keys_to_lookup = None
else:
missing_keys.update(all_index_missing)
keys_to_lookup.difference_update(all_index_missing)
return parent_map, missing_keys
def key_count(self):
"""Return an estimate of the number of keys in this index.
For CombinedGraphIndex this is approximated by the sum of the keys of
the child indices. As child indices may have duplicate keys this can
have a maximum error of the number of child indices * largest number of
keys in any index.
"""
while True:
try:
return sum((index.key_count() for index in self._indices), 0)
except errors.NoSuchFile:
self._reload_or_raise()
missing_keys = _missing_keys_from_parent_map
def _reload_or_raise(self):
"""We just got a NoSuchFile exception.
Try to reload the indices, if it fails, just raise the current
exception.
"""
if self._reload_func is None:
raise
exc_type, exc_value, exc_traceback = sys.exc_info()
trace.mutter('Trying to reload after getting exception: %s',
exc_value)
if not self._reload_func():
# We tried to reload, but nothing changed, so we fail anyway
trace.mutter('_reload_func indicated nothing has changed.'
' Raising original exception.')
raise exc_type, exc_value, exc_traceback
def set_sibling_indices(self, sibling_combined_graph_indices):
"""Set the CombinedGraphIndex objects to reorder after reordering self.
"""
self._sibling_indices = sibling_combined_graph_indices
def validate(self):
"""Validate that everything in the index can be accessed."""
while True:
try:
for index in self._indices:
index.validate()
return
except errors.NoSuchFile:
self._reload_or_raise()
class InMemoryGraphIndex(GraphIndexBuilder):
"""A GraphIndex which operates entirely out of memory and is mutable.
This is designed to allow the accumulation of GraphIndex entries during a
single write operation, where the accumulated entries need to be immediately
available - for example via a CombinedGraphIndex.
"""
def add_nodes(self, nodes):
"""Add nodes to the index.
:param nodes: An iterable of (key, node_refs, value) entries to add.
"""
if self.reference_lists:
for (key, value, node_refs) in nodes:
self.add_node(key, value, node_refs)
else:
for (key, value) in nodes:
self.add_node(key, value)
def iter_all_entries(self):
"""Iterate over all keys within the index
:return: An iterable of (index, key, reference_lists, value). There is no
defined order for the result iteration - it will be in the most
efficient order for the index (in this case dictionary hash order).
"""
if 'evil' in debug.debug_flags:
trace.mutter_callsite(3,
"iter_all_entries scales with size of history.")
if self.reference_lists:
for key, (absent, references, value) in self._nodes.iteritems():
if not absent:
yield self, key, value, references
else:
for key, (absent, references, value) in self._nodes.iteritems():
if not absent:
yield self, key, value
def iter_entries(self, keys):
"""Iterate over keys within the index.
:param keys: An iterable providing the keys to be retrieved.
:return: An iterable of (index, key, value, reference_lists). There is no
defined order for the result iteration - it will be in the most
efficient order for the index (keys iteration order in this case).
"""
# Note: See BTreeBuilder.iter_entries for an explanation of why we
# aren't using set().intersection() here
nodes = self._nodes
keys = [key for key in keys if key in nodes]
if self.reference_lists:
for key in keys:
node = nodes[key]
if not node[0]:
yield self, key, node[2], node[1]
else:
for key in keys:
node = nodes[key]
if not node[0]:
yield self, key, node[2]
def iter_entries_prefix(self, keys):
"""Iterate over keys within the index using prefix matching.
Prefix matching is applied within the tuple of a key, not to within
the bytestring of each key element. e.g. if you have the keys ('foo',
'bar'), ('foobar', 'gam') and do a prefix search for ('foo', None) then
only the former key is returned.
:param keys: An iterable providing the key prefixes to be retrieved.
Each key prefix takes the form of a tuple the length of a key, but
with the last N elements 'None' rather than a regular bytestring.
The first element cannot be 'None'.
:return: An iterable as per iter_all_entries, but restricted to the
keys with a matching prefix to those supplied. No additional keys
will be returned, and every match that is in the index will be
returned.
"""
# XXX: To much duplication with the GraphIndex class; consider finding
# a good place to pull out the actual common logic.
keys = set(keys)
if not keys:
return
if self._key_length == 1:
for key in keys:
# sanity check
if key[0] is None:
raise errors.BadIndexKey(key)
if len(key) != self._key_length:
raise errors.BadIndexKey(key)
node = self._nodes[key]
if node[0]:
continue
if self.reference_lists:
yield self, key, node[2], node[1]
else:
yield self, key, node[2]
return
nodes_by_key = self._get_nodes_by_key()
for key in keys:
# sanity check
if key[0] is None:
raise errors.BadIndexKey(key)
if len(key) != self._key_length:
raise errors.BadIndexKey(key)
# find what it refers to:
key_dict = nodes_by_key
elements = list(key)
# find the subdict to return
try:
while len(elements) and elements[0] is not None:
key_dict = key_dict[elements[0]]
elements.pop(0)
except KeyError:
# a non-existant lookup.
continue
if len(elements):
dicts = [key_dict]
while dicts:
key_dict = dicts.pop(-1)
# can't be empty or would not exist
item, value = key_dict.iteritems().next()
if type(value) == dict:
# push keys
dicts.extend(key_dict.itervalues())
else:
# yield keys
for value in key_dict.itervalues():
yield (self, ) + value
else:
yield (self, ) + key_dict
def key_count(self):
"""Return an estimate of the number of keys in this index.
For InMemoryGraphIndex the estimate is exact.
"""
return len(self._nodes) - len(self._absent_keys)
def validate(self):
"""In memory index's have no known corruption at the moment."""
class GraphIndexPrefixAdapter(object):
"""An adapter between GraphIndex with different key lengths.
Queries against this will emit queries against the adapted Graph with the
prefix added, queries for all items use iter_entries_prefix. The returned
nodes will have their keys and node references adjusted to remove the
prefix. Finally, an add_nodes_callback can be supplied - when called the
nodes and references being added will have prefix prepended.
"""
def __init__(self, adapted, prefix, missing_key_length,
add_nodes_callback=None):
"""Construct an adapter against adapted with prefix."""
self.adapted = adapted
self.prefix_key = prefix + (None,)*missing_key_length
self.prefix = prefix
self.prefix_len = len(prefix)
self.add_nodes_callback = add_nodes_callback
def add_nodes(self, nodes):
"""Add nodes to the index.
:param nodes: An iterable of (key, node_refs, value) entries to add.
"""
# save nodes in case its an iterator
nodes = tuple(nodes)
translated_nodes = []
try:
# Add prefix_key to each reference node_refs is a tuple of tuples,
# so split it apart, and add prefix_key to the internal reference
for (key, value, node_refs) in nodes:
adjusted_references = (
tuple(tuple(self.prefix + ref_node for ref_node in ref_list)
for ref_list in node_refs))
translated_nodes.append((self.prefix + key, value,
adjusted_references))
except ValueError:
# XXX: TODO add an explicit interface for getting the reference list
# status, to handle this bit of user-friendliness in the API more
# explicitly.
for (key, value) in nodes:
translated_nodes.append((self.prefix + key, value))
self.add_nodes_callback(translated_nodes)
def add_node(self, key, value, references=()):
"""Add a node to the index.
:param key: The key. keys are non-empty tuples containing
as many whitespace-free utf8 bytestrings as the key length
defined for this index.
:param references: An iterable of iterables of keys. Each is a
reference to another key.
:param value: The value to associate with the key. It may be any
bytes as long as it does not contain \0 or \n.
"""
self.add_nodes(((key, value, references), ))
def _strip_prefix(self, an_iter):
"""Strip prefix data from nodes and return it."""
for node in an_iter:
# cross checks
if node[1][:self.prefix_len] != self.prefix:
raise errors.BadIndexData(self)
for ref_list in node[3]:
for ref_node in ref_list:
if ref_node[:self.prefix_len] != self.prefix:
raise errors.BadIndexData(self)
yield node[0], node[1][self.prefix_len:], node[2], (
tuple(tuple(ref_node[self.prefix_len:] for ref_node in ref_list)
for ref_list in node[3]))
def iter_all_entries(self):
"""Iterate over all keys within the index
iter_all_entries is implemented against the adapted index using
iter_entries_prefix.
:return: An iterable of (index, key, reference_lists, value). There is no
defined order for the result iteration - it will be in the most
efficient order for the index (in this case dictionary hash order).
"""
return self._strip_prefix(self.adapted.iter_entries_prefix([self.prefix_key]))
def iter_entries(self, keys):
"""Iterate over keys within the index.
:param keys: An iterable providing the keys to be retrieved.
:return: An iterable of (index, key, value, reference_lists). There is no
defined order for the result iteration - it will be in the most
efficient order for the index (keys iteration order in this case).
"""
return self._strip_prefix(self.adapted.iter_entries(
self.prefix + key for key in keys))
def iter_entries_prefix(self, keys):
"""Iterate over keys within the index using prefix matching.
Prefix matching is applied within the tuple of a key, not to within
the bytestring of each key element. e.g. if you have the keys ('foo',
'bar'), ('foobar', 'gam') and do a prefix search for ('foo', None) then
only the former key is returned.
:param keys: An iterable providing the key prefixes to be retrieved.
Each key prefix takes the form of a tuple the length of a key, but
with the last N elements 'None' rather than a regular bytestring.
The first element cannot be 'None'.
:return: An iterable as per iter_all_entries, but restricted to the
keys with a matching prefix to those supplied. No additional keys
will be returned, and every match that is in the index will be
returned.
"""
return self._strip_prefix(self.adapted.iter_entries_prefix(
self.prefix + key for key in keys))
def key_count(self):
"""Return an estimate of the number of keys in this index.
For GraphIndexPrefixAdapter this is relatively expensive - key
iteration with the prefix is done.
"""
return len(list(self.iter_all_entries()))
def validate(self):
"""Call the adapted's validate."""
self.adapted.validate()
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