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# Copyright (C) 2007 Canonical Ltd
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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"""Indexing facilities."""
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'GraphIndexPrefixAdapter',
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from cStringIO import StringIO
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from bzrlib.lazy_import import lazy_import
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lazy_import(globals(), """
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from bzrlib import trace
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from bzrlib.trace import mutter
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from bzrlib import debug, errors
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_OPTION_KEY_ELEMENTS = "key_elements="
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_OPTION_NODE_REFS = "node_ref_lists="
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_SIGNATURE = "Bazaar Graph Index 1\n"
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_whitespace_re = re.compile('[\t\n\x0b\x0c\r\x00 ]')
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_newline_null_re = re.compile('[\n\0]')
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class GraphIndexBuilder(object):
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"""A builder that can build a GraphIndex.
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The resulting graph has the structure:
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_SIGNATURE OPTIONS NODES NEWLINE
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_SIGNATURE := 'Bazaar Graph Index 1' NEWLINE
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OPTIONS := 'node_ref_lists=' DIGITS NEWLINE
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NODE := KEY NULL ABSENT? NULL REFERENCES NULL VALUE NEWLINE
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KEY := Not-whitespace-utf8
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REFERENCES := REFERENCE_LIST (TAB REFERENCE_LIST){node_ref_lists - 1}
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REFERENCE_LIST := (REFERENCE (CR REFERENCE)*)?
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REFERENCE := DIGITS ; digits is the byte offset in the index of the
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VALUE := no-newline-no-null-bytes
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def __init__(self, reference_lists=0, key_elements=1):
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"""Create a GraphIndex builder.
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:param reference_lists: The number of node references lists for each
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:param key_elements: The number of bytestrings in each key.
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self.reference_lists = reference_lists
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self._nodes_by_key = {}
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self._key_length = key_elements
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def _check_key(self, key):
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"""Raise BadIndexKey if key is not a valid key for this index."""
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if type(key) != tuple:
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raise errors.BadIndexKey(key)
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if self._key_length != len(key):
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raise errors.BadIndexKey(key)
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if not element or _whitespace_re.search(element) is not None:
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raise errors.BadIndexKey(element)
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def add_node(self, key, value, references=()):
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"""Add a node to the index.
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:param key: The key. keys are non-empty tuples containing
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as many whitespace-free utf8 bytestrings as the key length
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defined for this index.
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:param references: An iterable of iterables of keys. Each is a
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reference to another key.
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:param value: The value to associate with the key. It may be any
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bytes as long as it does not contain \0 or \n.
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if _newline_null_re.search(value) is not None:
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raise errors.BadIndexValue(value)
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if len(references) != self.reference_lists:
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raise errors.BadIndexValue(references)
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for reference_list in references:
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for reference in reference_list:
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self._check_key(reference)
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if reference not in self._nodes:
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self._nodes[reference] = ('a', (), '')
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node_refs.append(tuple(reference_list))
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if key in self._nodes and self._nodes[key][0] == '':
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raise errors.BadIndexDuplicateKey(key, self)
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self._nodes[key] = ('', tuple(node_refs), value)
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if self._key_length > 1:
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key_dict = self._nodes_by_key
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if self.reference_lists:
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key_value = key, value, tuple(node_refs)
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key_value = key, value
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# possibly should do this on-demand, but it seems likely it is
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# For a key of (foo, bar, baz) create
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# _nodes_by_key[foo][bar][baz] = key_value
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for subkey in key[:-1]:
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key_dict = key_dict.setdefault(subkey, {})
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key_dict[key[-1]] = key_value
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lines.append(_OPTION_NODE_REFS + str(self.reference_lists) + '\n')
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lines.append(_OPTION_KEY_ELEMENTS + str(self._key_length) + '\n')
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lines.append(_OPTION_LEN + str(len(self._keys)) + '\n')
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prefix_length = sum(len(x) for x in lines)
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# references are byte offsets. To avoid having to do nasty
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# polynomial work to resolve offsets (references to later in the
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# file cannot be determined until all the inbetween references have
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# been calculated too) we pad the offsets with 0's to make them be
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# of consistent length. Using binary offsets would break the trivial
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# to calculate the width of zero's needed we do three passes:
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# one to gather all the non-reference data and the number of references.
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# one to pad all the data with reference-length and determine entry
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# forward sorted by key. In future we may consider topological sorting,
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# at the cost of table scans for direct lookup, or a second index for
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nodes = sorted(self._nodes.items())
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# if we do not prepass, we don't know how long it will be up front.
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expected_bytes = None
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# we only need to pre-pass if we have reference lists at all.
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if self.reference_lists:
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non_ref_bytes = prefix_length
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# TODO use simple multiplication for the constants in this loop.
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for key, (absent, references, value) in nodes:
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# record the offset known *so far* for this key:
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# the non reference bytes to date, and the total references to
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# date - saves reaccumulating on the second pass
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key_offset_info.append((key, non_ref_bytes, total_references))
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# key is literal, value is literal, there are 3 null's, 1 NL
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# key is variable length tuple, \x00 between elements
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non_ref_bytes += sum(len(element) for element in key)
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if self._key_length > 1:
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non_ref_bytes += self._key_length - 1
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# value is literal bytes, there are 3 null's, 1 NL.
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non_ref_bytes += len(value) + 3 + 1
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# one byte for absent if set.
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elif self.reference_lists:
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# (ref_lists -1) tabs
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non_ref_bytes += self.reference_lists - 1
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# (ref-1 cr's per ref_list)
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for ref_list in references:
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# how many references across the whole file?
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total_references += len(ref_list)
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# accrue reference separators
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non_ref_bytes += len(ref_list) - 1
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# how many digits are needed to represent the total byte count?
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possible_total_bytes = non_ref_bytes + total_references*digits
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while 10 ** digits < possible_total_bytes:
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possible_total_bytes = non_ref_bytes + total_references*digits
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expected_bytes = possible_total_bytes + 1 # terminating newline
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# resolve key addresses.
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for key, non_ref_bytes, total_references in key_offset_info:
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key_addresses[key] = non_ref_bytes + total_references*digits
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format_string = '%%0%sd' % digits
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for key, (absent, references, value) in nodes:
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flattened_references = []
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for ref_list in references:
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for reference in ref_list:
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ref_addresses.append(format_string % key_addresses[reference])
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flattened_references.append('\r'.join(ref_addresses))
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string_key = '\x00'.join(key)
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lines.append("%s\x00%s\x00%s\x00%s\n" % (string_key, absent,
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'\t'.join(flattened_references), value))
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result = StringIO(''.join(lines))
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if expected_bytes and len(result.getvalue()) != expected_bytes:
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raise errors.BzrError('Failed index creation. Internal error:'
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' mismatched output length and expected length: %d %d' %
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(len(result.getvalue()), expected_bytes))
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return StringIO(''.join(lines))
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class GraphIndex(object):
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"""An index for data with embedded graphs.
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The index maps keys to a list of key reference lists, and a value.
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Each node has the same number of key reference lists. Each key reference
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list can be empty or an arbitrary length. The value is an opaque NULL
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terminated string without any newlines. The storage of the index is
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hidden in the interface: keys and key references are always tuples of
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bytestrings, never the internal representation (e.g. dictionary offsets).
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It is presumed that the index will not be mutated - it is static data.
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Successive iter_all_entries calls will read the entire index each time.
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Additionally, iter_entries calls will read the index linearly until the
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desired keys are found. XXX: This must be fixed before the index is
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suitable for production use. :XXX
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def __init__(self, transport, name, size):
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"""Open an index called name on transport.
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:param transport: A bzrlib.transport.Transport.
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:param name: A path to provide to transport API calls.
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:param size: The size of the index in bytes. This is used for bisection
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logic to perform partial index reads. While the size could be
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obtained by statting the file this introduced an additional round
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trip that is avoided by having it supplied.
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self._transport = transport
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self._key_count = None
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self._keys_by_offset = None
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self._nodes_by_key = None
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def _buffer_all(self):
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"""Buffer all the index data.
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Mutates self._nodes and self.keys_by_offset.
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if 'index' in debug.debug_flags:
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mutter('Reading entire index %s', self._transport.abspath(self._name))
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stream = self._transport.get(self._name)
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self._read_prefix(stream)
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expected_elements = 3 + self._key_length
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# raw data keyed by offset
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self._keys_by_offset = {}
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# ready-to-return key:value or key:value, node_ref_lists
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self._nodes_by_key = {}
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for line in stream.readlines():
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elements = line.split('\0')
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if len(elements) != expected_elements:
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raise errors.BadIndexData(self)
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key = tuple(elements[:self._key_length])
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absent, references, value = elements[-3:]
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value = value[:-1] # remove the newline
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for ref_string in references.split('\t'):
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ref_lists.append(tuple([
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int(ref) for ref in ref_string.split('\r') if ref
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ref_lists = tuple(ref_lists)
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self._keys_by_offset[pos] = (key, absent, ref_lists, value)
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for key, absent, references, value in self._keys_by_offset.itervalues():
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# resolve references:
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if self.node_ref_lists:
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for ref_list in references:
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node_refs.append(tuple([self._keys_by_offset[ref][0] for ref in ref_list]))
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node_value = (value, tuple(node_refs))
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self._nodes[key] = node_value
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if self._key_length > 1:
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subkey = list(reversed(key[:-1]))
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key_dict = self._nodes_by_key
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if self.node_ref_lists:
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key_value = key, node_value[0], node_value[1]
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key_value = key, node_value
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# possibly should do this on-demand, but it seems likely it is
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# For a key of (foo, bar, baz) create
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# _nodes_by_key[foo][bar][baz] = key_value
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for subkey in key[:-1]:
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key_dict = key_dict.setdefault(subkey, {})
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key_dict[key[-1]] = key_value
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# cache the keys for quick set intersections
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self._keys = set(self._nodes)
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# there must be one line - the empty trailer line.
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raise errors.BadIndexData(self)
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def iter_all_entries(self):
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"""Iterate over all keys within the index.
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:return: An iterable of (index, key, value) or (index, key, value, reference_lists).
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The former tuple is used when there are no reference lists in the
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index, making the API compatible with simple key:value index types.
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There is no defined order for the result iteration - it will be in
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the most efficient order for the index.
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if 'evil' in debug.debug_flags:
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trace.mutter_callsite(3,
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"iter_all_entries scales with size of history.")
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if self._nodes is None:
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if self.node_ref_lists:
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for key, (value, node_ref_lists) in self._nodes.iteritems():
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yield self, key, value, node_ref_lists
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for key, value in self._nodes.iteritems():
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yield self, key, value
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def _read_prefix(self, stream):
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signature = stream.read(len(self._signature()))
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if not signature == self._signature():
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raise errors.BadIndexFormatSignature(self._name, GraphIndex)
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options_line = stream.readline()
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if not options_line.startswith(_OPTION_NODE_REFS):
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raise errors.BadIndexOptions(self)
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self.node_ref_lists = int(options_line[len(_OPTION_NODE_REFS):-1])
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raise errors.BadIndexOptions(self)
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options_line = stream.readline()
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if not options_line.startswith(_OPTION_KEY_ELEMENTS):
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raise errors.BadIndexOptions(self)
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self._key_length = int(options_line[len(_OPTION_KEY_ELEMENTS):-1])
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raise errors.BadIndexOptions(self)
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options_line = stream.readline()
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if not options_line.startswith(_OPTION_LEN):
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raise errors.BadIndexOptions(self)
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self._key_count = int(options_line[len(_OPTION_LEN):-1])
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raise errors.BadIndexOptions(self)
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def iter_entries(self, keys):
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"""Iterate over keys within the index.
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:param keys: An iterable providing the keys to be retrieved.
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:return: An iterable as per iter_all_entries, but restricted to the
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keys supplied. No additional keys will be returned, and every
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key supplied that is in the index will be returned.
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if self._nodes is None:
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keys = keys.intersection(self._keys)
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if self.node_ref_lists:
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value, node_refs = self._nodes[key]
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yield self, key, value, node_refs
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yield self, key, self._nodes[key]
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def iter_entries_prefix(self, keys):
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"""Iterate over keys within the index using prefix matching.
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Prefix matching is applied within the tuple of a key, not to within
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the bytestring of each key element. e.g. if you have the keys ('foo',
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'bar'), ('foobar', 'gam') and do a prefix search for ('foo', None) then
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only the former key is returned.
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:param keys: An iterable providing the key prefixes to be retrieved.
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Each key prefix takes the form of a tuple the length of a key, but
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with the last N elements 'None' rather than a regular bytestring.
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The first element cannot be 'None'.
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:return: An iterable as per iter_all_entries, but restricted to the
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keys with a matching prefix to those supplied. No additional keys
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will be returned, and every match that is in the index will be
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# load data - also finds key lengths
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if self._nodes is None:
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if self._key_length == 1:
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raise errors.BadIndexKey(key)
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if len(key) != self._key_length:
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raise errors.BadIndexKey(key)
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if self.node_ref_lists:
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value, node_refs = self._nodes[key]
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yield self, key, value, node_refs
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yield self, key, self._nodes[key]
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raise errors.BadIndexKey(key)
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if len(key) != self._key_length:
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raise errors.BadIndexKey(key)
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# find what it refers to:
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key_dict = self._nodes_by_key
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# find the subdict whose contents should be returned.
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while len(elements) and elements[0] is not None:
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key_dict = key_dict[elements[0]]
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# a non-existant lookup.
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key_dict = dicts.pop(-1)
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# can't be empty or would not exist
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item, value = key_dict.iteritems().next()
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if type(value) == dict:
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dicts.extend(key_dict.itervalues())
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for value in key_dict.itervalues():
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# each value is the key:value:node refs tuple
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yield (self, ) + value
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# the last thing looked up was a terminal element
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yield (self, ) + key_dict
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"""Return an estimate of the number of keys in this index.
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For GraphIndex the estimate is exact.
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if self._key_count is None:
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# really this should just read the prefix
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return self._key_count
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def _signature(self):
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"""The file signature for this index type."""
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"""Validate that everything in the index can be accessed."""
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# iter_all validates completely at the moment, so just do that.
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for node in self.iter_all_entries():
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class CombinedGraphIndex(object):
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"""A GraphIndex made up from smaller GraphIndices.
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The backing indices must implement GraphIndex, and are presumed to be
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Queries against the combined index will be made against the first index,
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and then the second and so on. The order of index's can thus influence
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performance significantly. For example, if one index is on local disk and a
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second on a remote server, the local disk index should be before the other
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def __init__(self, indices):
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"""Create a CombinedGraphIndex backed by indices.
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:param indices: An ordered list of indices to query for data.
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self._indices = indices
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self.__class__.__name__,
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', '.join(map(repr, self._indices)))
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def insert_index(self, pos, index):
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"""Insert a new index in the list of indices to query.
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:param pos: The position to insert the index.
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:param index: The index to insert.
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self._indices.insert(pos, index)
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def iter_all_entries(self):
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"""Iterate over all keys within the index
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Duplicate keys across child indices are presumed to have the same
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value and are only reported once.
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:return: An iterable of (index, key, reference_lists, value).
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There is no defined order for the result iteration - it will be in
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the most efficient order for the index.
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for index in self._indices:
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for node in index.iter_all_entries():
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if node[1] not in seen_keys:
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seen_keys.add(node[1])
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def iter_entries(self, keys):
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"""Iterate over keys within the index.
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Duplicate keys across child indices are presumed to have the same
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value and are only reported once.
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:param keys: An iterable providing the keys to be retrieved.
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:return: An iterable of (index, key, reference_lists, value). There is no
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defined order for the result iteration - it will be in the most
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efficient order for the index.
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for index in self._indices:
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for node in index.iter_entries(keys):
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def iter_entries_prefix(self, keys):
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"""Iterate over keys within the index using prefix matching.
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Duplicate keys across child indices are presumed to have the same
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value and are only reported once.
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Prefix matching is applied within the tuple of a key, not to within
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the bytestring of each key element. e.g. if you have the keys ('foo',
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'bar'), ('foobar', 'gam') and do a prefix search for ('foo', None) then
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only the former key is returned.
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:param keys: An iterable providing the key prefixes to be retrieved.
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Each key prefix takes the form of a tuple the length of a key, but
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with the last N elements 'None' rather than a regular bytestring.
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The first element cannot be 'None'.
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:return: An iterable as per iter_all_entries, but restricted to the
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keys with a matching prefix to those supplied. No additional keys
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will be returned, and every match that is in the index will be
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for index in self._indices:
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for node in index.iter_entries_prefix(keys):
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if node[1] in seen_keys:
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seen_keys.add(node[1])
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"""Return an estimate of the number of keys in this index.
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For CombinedGraphIndex this is approximated by the sum of the keys of
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the child indices. As child indices may have duplicate keys this can
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have a maximum error of the number of child indices * largest number of
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return sum((index.key_count() for index in self._indices), 0)
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"""Validate that everything in the index can be accessed."""
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for index in self._indices:
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class InMemoryGraphIndex(GraphIndexBuilder):
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"""A GraphIndex which operates entirely out of memory and is mutable.
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This is designed to allow the accumulation of GraphIndex entries during a
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single write operation, where the accumulated entries need to be immediately
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available - for example via a CombinedGraphIndex.
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def add_nodes(self, nodes):
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"""Add nodes to the index.
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:param nodes: An iterable of (key, node_refs, value) entries to add.
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if self.reference_lists:
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for (key, value, node_refs) in nodes:
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self.add_node(key, value, node_refs)
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for (key, value) in nodes:
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self.add_node(key, value)
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def iter_all_entries(self):
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"""Iterate over all keys within the index
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:return: An iterable of (index, key, reference_lists, value). There is no
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defined order for the result iteration - it will be in the most
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efficient order for the index (in this case dictionary hash order).
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if 'evil' in debug.debug_flags:
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trace.mutter_callsite(3,
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"iter_all_entries scales with size of history.")
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if self.reference_lists:
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for key, (absent, references, value) in self._nodes.iteritems():
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yield self, key, value, references
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for key, (absent, references, value) in self._nodes.iteritems():
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yield self, key, value
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def iter_entries(self, keys):
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"""Iterate over keys within the index.
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:param keys: An iterable providing the keys to be retrieved.
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:return: An iterable of (index, key, reference_lists, value). There is no
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defined order for the result iteration - it will be in the most
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efficient order for the index (keys iteration order in this case).
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if self.reference_lists:
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for key in keys.intersection(self._keys):
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node = self._nodes[key]
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yield self, key, node[2], node[1]
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for key in keys.intersection(self._keys):
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node = self._nodes[key]
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yield self, key, node[2]
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def iter_entries_prefix(self, keys):
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"""Iterate over keys within the index using prefix matching.
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Prefix matching is applied within the tuple of a key, not to within
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the bytestring of each key element. e.g. if you have the keys ('foo',
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'bar'), ('foobar', 'gam') and do a prefix search for ('foo', None) then
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only the former key is returned.
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:param keys: An iterable providing the key prefixes to be retrieved.
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Each key prefix takes the form of a tuple the length of a key, but
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with the last N elements 'None' rather than a regular bytestring.
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The first element cannot be 'None'.
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:return: An iterable as per iter_all_entries, but restricted to the
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keys with a matching prefix to those supplied. No additional keys
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will be returned, and every match that is in the index will be
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# XXX: To much duplication with the GraphIndex class; consider finding
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# a good place to pull out the actual common logic.
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if self._key_length == 1:
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raise errors.BadIndexKey(key)
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if len(key) != self._key_length:
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raise errors.BadIndexKey(key)
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node = self._nodes[key]
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if self.reference_lists:
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yield self, key, node[2], node[1]
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yield self, key, node[2]
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raise errors.BadIndexKey(key)
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if len(key) != self._key_length:
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raise errors.BadIndexKey(key)
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# find what it refers to:
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key_dict = self._nodes_by_key
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# find the subdict to return
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while len(elements) and elements[0] is not None:
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key_dict = key_dict[elements[0]]
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# a non-existant lookup.
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key_dict = dicts.pop(-1)
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# can't be empty or would not exist
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item, value = key_dict.iteritems().next()
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if type(value) == dict:
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dicts.extend(key_dict.itervalues())
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for value in key_dict.itervalues():
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yield (self, ) + value
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yield (self, ) + key_dict
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"""Return an estimate of the number of keys in this index.
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For InMemoryGraphIndex the estimate is exact.
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return len(self._keys)
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"""In memory index's have no known corruption at the moment."""
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class GraphIndexPrefixAdapter(object):
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"""An adapter between GraphIndex with different key lengths.
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Queries against this will emit queries against the adapted Graph with the
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prefix added, queries for all items use iter_entries_prefix. The returned
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nodes will have their keys and node references adjusted to remove the
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prefix. Finally, an add_nodes_callback can be supplied - when called the
747
nodes and references being added will have prefix prepended.
750
def __init__(self, adapted, prefix, missing_key_length,
751
add_nodes_callback=None):
752
"""Construct an adapter against adapted with prefix."""
753
self.adapted = adapted
754
self.prefix_key = prefix + (None,)*missing_key_length
756
self.prefix_len = len(prefix)
757
self.add_nodes_callback = add_nodes_callback
759
def add_nodes(self, nodes):
760
"""Add nodes to the index.
762
:param nodes: An iterable of (key, node_refs, value) entries to add.
764
# save nodes in case its an iterator
766
translated_nodes = []
768
# Add prefix_key to each reference node_refs is a tuple of tuples,
769
# so split it apart, and add prefix_key to the internal reference
770
for (key, value, node_refs) in nodes:
771
adjusted_references = (
772
tuple(tuple(self.prefix + ref_node for ref_node in ref_list)
773
for ref_list in node_refs))
774
translated_nodes.append((self.prefix + key, value,
775
adjusted_references))
777
# XXX: TODO add an explicit interface for getting the reference list
778
# status, to handle this bit of user-friendliness in the API more
780
for (key, value) in nodes:
781
translated_nodes.append((self.prefix + key, value))
782
self.add_nodes_callback(translated_nodes)
784
def add_node(self, key, value, references=()):
785
"""Add a node to the index.
787
:param key: The key. keys are non-empty tuples containing
788
as many whitespace-free utf8 bytestrings as the key length
789
defined for this index.
790
:param references: An iterable of iterables of keys. Each is a
791
reference to another key.
792
:param value: The value to associate with the key. It may be any
793
bytes as long as it does not contain \0 or \n.
795
self.add_nodes(((key, value, references), ))
797
def _strip_prefix(self, an_iter):
798
"""Strip prefix data from nodes and return it."""
801
if node[1][:self.prefix_len] != self.prefix:
802
raise errors.BadIndexData(self)
803
for ref_list in node[3]:
804
for ref_node in ref_list:
805
if ref_node[:self.prefix_len] != self.prefix:
806
raise errors.BadIndexData(self)
807
yield node[0], node[1][self.prefix_len:], node[2], (
808
tuple(tuple(ref_node[self.prefix_len:] for ref_node in ref_list)
809
for ref_list in node[3]))
811
def iter_all_entries(self):
812
"""Iterate over all keys within the index
814
iter_all_entries is implemented against the adapted index using
817
:return: An iterable of (index, key, reference_lists, value). There is no
818
defined order for the result iteration - it will be in the most
819
efficient order for the index (in this case dictionary hash order).
821
return self._strip_prefix(self.adapted.iter_entries_prefix([self.prefix_key]))
823
def iter_entries(self, keys):
824
"""Iterate over keys within the index.
826
:param keys: An iterable providing the keys to be retrieved.
827
:return: An iterable of (key, reference_lists, value). There is no
828
defined order for the result iteration - it will be in the most
829
efficient order for the index (keys iteration order in this case).
831
return self._strip_prefix(self.adapted.iter_entries(
832
self.prefix + key for key in keys))
834
def iter_entries_prefix(self, keys):
835
"""Iterate over keys within the index using prefix matching.
837
Prefix matching is applied within the tuple of a key, not to within
838
the bytestring of each key element. e.g. if you have the keys ('foo',
839
'bar'), ('foobar', 'gam') and do a prefix search for ('foo', None) then
840
only the former key is returned.
842
:param keys: An iterable providing the key prefixes to be retrieved.
843
Each key prefix takes the form of a tuple the length of a key, but
844
with the last N elements 'None' rather than a regular bytestring.
845
The first element cannot be 'None'.
846
:return: An iterable as per iter_all_entries, but restricted to the
847
keys with a matching prefix to those supplied. No additional keys
848
will be returned, and every match that is in the index will be
851
return self._strip_prefix(self.adapted.iter_entries_prefix(
852
self.prefix + key for key in keys))
855
"""Return an estimate of the number of keys in this index.
857
For GraphIndexPrefixAdapter this is relatively expensive - key
858
iteration with the prefix is done.
860
return len(list(self.iter_all_entries()))
863
"""Call the adapted's validate."""
864
self.adapted.validate()
added
removed
bzrlib/index.py
