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# Copyright (C) 2007, 2008 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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"""Indexing facilities."""
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'GraphIndexPrefixAdapter',
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from bisect import bisect_right
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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.bisect_multi import bisect_multi_bytes
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from bzrlib.revision import NULL_REVISION
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from bzrlib.trace import mutter
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_HEADER_READV = (0, 200)
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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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def _has_key_from_parent_map(self, key):
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"""Check if this index has one key.
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If it's possible to check for multiple keys at once through
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calling get_parent_map that should be faster.
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return (key in self.get_parent_map([key]))
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def _missing_keys_from_parent_map(self, keys):
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return set(keys) - set(self.get_parent_map(keys))
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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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# A dict of {key: (absent, ref_lists, value)}
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self._nodes_by_key = None
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self._key_length = key_elements
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self._optimize_for_size = False
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self._combine_backing_indices = True
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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 _external_references(self):
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"""Return references that are not present in this index.
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# TODO: JAM 2008-11-21 This makes an assumption about how the reference
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# lists are used. It is currently correct for pack-0.92 through
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# 1.9, which use the node references (3rd column) second
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# reference list as the compression parent. Perhaps this should
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# be moved into something higher up the stack, since it
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# makes assumptions about how the index is used.
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if self.reference_lists > 1:
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for node in self.iter_all_entries():
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refs.update(node[3][1])
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# If reference_lists == 0 there can be no external references, and
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# if reference_lists == 1, then there isn't a place to store the
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def _get_nodes_by_key(self):
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if self._nodes_by_key is None:
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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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key_dict = nodes_by_key
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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, references
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for key, (absent, references, value) in self._nodes.iteritems():
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key_dict = nodes_by_key
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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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self._nodes_by_key = nodes_by_key
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return self._nodes_by_key
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def _update_nodes_by_key(self, key, value, node_refs):
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"""Update the _nodes_by_key dict with a new key.
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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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if self._nodes_by_key is None:
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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, node_refs
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key_value = 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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def _check_key_ref_value(self, key, references, value):
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"""Check that 'key' and 'references' are all valid.
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:param key: A key tuple. Must conform to the key interface (be a tuple,
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be of the right length, not have any whitespace or nulls in any key
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:param references: An iterable of reference lists. Something like
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[[(ref, key)], [(ref, key), (other, key)]]
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:param value: The value associate with this key. Must not contain
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newlines or null characters.
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:return: (node_refs, absent_references)
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node_refs basically a packed form of 'references' where all
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absent_references reference keys that are not in self._nodes.
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This may contain duplicates if the same key is
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referenced in multiple lists.
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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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absent_references = []
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for reference_list in references:
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for reference in reference_list:
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# If reference *is* in self._nodes, then we know it has already
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if reference not in self._nodes:
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self._check_key(reference)
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absent_references.append(reference)
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node_refs.append(tuple(reference_list))
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return tuple(node_refs), absent_references
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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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absent_references) = self._check_key_ref_value(key, references, value)
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if key in self._nodes and self._nodes[key][0] != 'a':
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raise errors.BadIndexDuplicateKey(key, self)
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for reference in absent_references:
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# There may be duplicates, but I don't think it is worth worrying
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self._nodes[reference] = ('a', (), '')
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self._nodes[key] = ('', node_refs, value)
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if self._nodes_by_key is not None and self._key_length > 1:
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self._update_nodes_by_key(key, value, node_refs)
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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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def set_optimize(self, for_size=None, combine_backing_indices=None):
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"""Change how the builder tries to optimize the result.
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:param for_size: Tell the builder to try and make the index as small as
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:param combine_backing_indices: If the builder spills to disk to save
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memory, should the on-disk indices be combined. Set to True if you
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are going to be probing the index, but to False if you are not. (If
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you are not querying, then the time spent combining is wasted.)
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# GraphIndexBuilder itself doesn't pay attention to the flag yet, but
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if for_size is not None:
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self._optimize_for_size = for_size
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if combine_backing_indices is not None:
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self._combine_backing_indices = combine_backing_indices
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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 as well as requiring stat'able transports, both of which are
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avoided by having it supplied. If size is None, then bisection
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support will be disabled and accessing the index will just stream
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self._transport = transport
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# Becomes a dict of key:(value, reference-list-byte-locations) used by
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# the bisection interface to store parsed but not resolved keys.
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self._bisect_nodes = None
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# Becomes a dict of key:(value, reference-list-keys) which are ready to
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# be returned directly to callers.
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# a sorted list of slice-addresses for the parsed bytes of the file.
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# e.g. (0,1) would mean that byte 0 is parsed.
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self._parsed_byte_map = []
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# a sorted list of keys matching each slice address for parsed bytes
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# e.g. (None, 'foo@bar') would mean that the first byte contained no
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# key, and the end byte of the slice is the of the data for 'foo@bar'
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self._parsed_key_map = []
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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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# The number of bytes we've read so far in trying to process this file
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def __eq__(self, other):
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"""Equal when self and other were created with the same parameters."""
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type(self) == type(other) and
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self._transport == other._transport and
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self._name == other._name and
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self._size == other._size)
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def __ne__(self, other):
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return not self.__eq__(other)
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return "%s(%r)" % (self.__class__.__name__,
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self._transport.abspath(self._name))
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def _buffer_all(self, stream=None):
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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 self._nodes is not None:
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# We already did this
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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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self._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 = None
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lines = stream.read().split('\n')
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_, _, _, trailers = self._parse_lines(lines, pos)
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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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node_value = (value, self._resolve_references(references))
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self._nodes[key] = node_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 external_references(self, ref_list_num):
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"""Return references that are not present in this index.
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if ref_list_num + 1 > self.node_ref_lists:
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raise ValueError('No ref list %d, index has %d ref lists'
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% (ref_list_num, self.node_ref_lists))
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for key, (value, ref_lists) in self._nodes.iteritems():
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ref_list = ref_lists[ref_list_num]
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refs.update(ref_list)
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return refs - self._keys
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def _get_nodes_by_key(self):
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if self._nodes_by_key is None:
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if self.node_ref_lists:
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for key, (value, references) in self._nodes.iteritems():
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key_dict = nodes_by_key
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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, references
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for key, value in self._nodes.iteritems():
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key_dict = nodes_by_key
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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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self._nodes_by_key = nodes_by_key
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return self._nodes_by_key
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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 _resolve_references(self, references):
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"""Return the resolved key references for references.
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References are resolved by looking up the location of the key in the
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_keys_by_offset map and substituting the key name, preserving ordering.
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:param references: An iterable of iterables of key locations. e.g.
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:return: A tuple of tuples of keys.
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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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return tuple(node_refs)
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def _find_index(self, range_map, key):
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"""Helper for the _parsed_*_index calls.
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Given a range map - [(start, end), ...], finds the index of the range
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in the map for key if it is in the map, and if it is not there, the
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immediately preceeding range in the map.
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result = bisect_right(range_map, key) - 1
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if result + 1 < len(range_map):
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# check the border condition, it may be in result + 1
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if range_map[result + 1][0] == key[0]:
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def _parsed_byte_index(self, offset):
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"""Return the index of the entry immediately before offset.
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e.g. if the parsed map has regions 0,10 and 11,12 parsed, meaning that
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there is one unparsed byte (the 11th, addressed as[10]). then:
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asking for 0 will return 0
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asking for 10 will return 0
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asking for 11 will return 1
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asking for 12 will return 1
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return self._find_index(self._parsed_byte_map, key)
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def _parsed_key_index(self, key):
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"""Return the index of the entry immediately before key.
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e.g. if the parsed map has regions (None, 'a') and ('b','c') parsed,
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meaning that keys from None to 'a' inclusive, and 'b' to 'c' inclusive
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have been parsed, then:
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asking for '' will return 0
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asking for 'a' will return 0
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asking for 'b' will return 1
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asking for 'e' will return 1
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search_key = (key, None)
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return self._find_index(self._parsed_key_map, search_key)
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def _is_parsed(self, offset):
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"""Returns True if offset has been parsed."""
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index = self._parsed_byte_index(offset)
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if index == len(self._parsed_byte_map):
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return offset < self._parsed_byte_map[index - 1][1]
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start, end = self._parsed_byte_map[index]
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return offset >= start and offset < end
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def _iter_entries_from_total_buffer(self, keys):
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"""Iterate over keys when the entire index is parsed."""
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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(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._size is None and self._nodes is None:
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# We fit about 20 keys per minimum-read (4K), so if we are looking for
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# more than 1/20th of the index its likely (assuming homogenous key
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# spread) that we'll read the entire index. If we're going to do that,
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# buffer the whole thing. A better analysis might take key spread into
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# account - but B+Tree indices are better anyway.
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# We could look at all data read, and use a threshold there, which will
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# trigger on ancestry walks, but that is not yet fully mapped out.
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if self._nodes is None and len(keys) * 20 > self.key_count():
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if self._nodes is not None:
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return self._iter_entries_from_total_buffer(keys)
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return (result[1] for result in bisect_multi_bytes(
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self._lookup_keys_via_location, self._size, 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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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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WARNING: Note that this method currently causes a full index parse
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unconditionally (which is reasonably appropriate as it is a means for
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thunking many small indices into one larger one and still supplies
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iter_all_entries at the thunk layer).
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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
666
yield self, key, self._nodes[key]
668
nodes_by_key = self._get_nodes_by_key()
672
raise errors.BadIndexKey(key)
673
if len(key) != self._key_length:
674
raise errors.BadIndexKey(key)
675
# find what it refers to:
676
key_dict = nodes_by_key
678
# find the subdict whose contents should be returned.
680
while len(elements) and elements[0] is not None:
681
key_dict = key_dict[elements[0]]
684
# a non-existant lookup.
689
key_dict = dicts.pop(-1)
690
# can't be empty or would not exist
691
item, value = key_dict.iteritems().next()
692
if type(value) == dict:
694
dicts.extend(key_dict.itervalues())
697
for value in key_dict.itervalues():
698
# each value is the key:value:node refs tuple
700
yield (self, ) + value
702
# the last thing looked up was a terminal element
703
yield (self, ) + key_dict
706
"""Return an estimate of the number of keys in this index.
708
For GraphIndex the estimate is exact.
710
if self._key_count is None:
711
self._read_and_parse([_HEADER_READV])
712
return self._key_count
714
def _lookup_keys_via_location(self, location_keys):
715
"""Public interface for implementing bisection.
717
If _buffer_all has been called, then all the data for the index is in
718
memory, and this method should not be called, as it uses a separate
719
cache because it cannot pre-resolve all indices, which buffer_all does
722
:param location_keys: A list of location(byte offset), key tuples.
723
:return: A list of (location_key, result) tuples as expected by
724
bzrlib.bisect_multi.bisect_multi_bytes.
726
# Possible improvements:
727
# - only bisect lookup each key once
728
# - sort the keys first, and use that to reduce the bisection window
730
# this progresses in three parts:
733
# attempt to answer the question from the now in memory data.
734
# build the readv request
735
# for each location, ask for 800 bytes - much more than rows we've seen
738
for location, key in location_keys:
739
# can we answer from cache?
740
if self._bisect_nodes and key in self._bisect_nodes:
741
# We have the key parsed.
743
index = self._parsed_key_index(key)
744
if (len(self._parsed_key_map) and
745
self._parsed_key_map[index][0] <= key and
746
(self._parsed_key_map[index][1] >= key or
747
# end of the file has been parsed
748
self._parsed_byte_map[index][1] == self._size)):
749
# the key has been parsed, so no lookup is needed even if its
752
# - if we have examined this part of the file already - yes
753
index = self._parsed_byte_index(location)
754
if (len(self._parsed_byte_map) and
755
self._parsed_byte_map[index][0] <= location and
756
self._parsed_byte_map[index][1] > location):
757
# the byte region has been parsed, so no read is needed.
760
if location + length > self._size:
761
length = self._size - location
762
# todo, trim out parsed locations.
764
readv_ranges.append((location, length))
765
# read the header if needed
766
if self._bisect_nodes is None:
767
readv_ranges.append(_HEADER_READV)
768
self._read_and_parse(readv_ranges)
770
if self._nodes is not None:
771
# _read_and_parse triggered a _buffer_all because we requested the
773
for location, key in location_keys:
774
if key not in self._nodes: # not present
775
result.append(((location, key), False))
776
elif self.node_ref_lists:
777
value, refs = self._nodes[key]
778
result.append(((location, key),
779
(self, key, value, refs)))
781
result.append(((location, key),
782
(self, key, self._nodes[key])))
785
# - figure out <, >, missing, present
786
# - result present references so we can return them.
787
# keys that we cannot answer until we resolve references
788
pending_references = []
789
pending_locations = set()
790
for location, key in location_keys:
791
# can we answer from cache?
792
if key in self._bisect_nodes:
793
# the key has been parsed, so no lookup is needed
794
if self.node_ref_lists:
795
# the references may not have been all parsed.
796
value, refs = self._bisect_nodes[key]
797
wanted_locations = []
798
for ref_list in refs:
800
if ref not in self._keys_by_offset:
801
wanted_locations.append(ref)
803
pending_locations.update(wanted_locations)
804
pending_references.append((location, key))
806
result.append(((location, key), (self, key,
807
value, self._resolve_references(refs))))
809
result.append(((location, key),
810
(self, key, self._bisect_nodes[key])))
813
# has the region the key should be in, been parsed?
814
index = self._parsed_key_index(key)
815
if (self._parsed_key_map[index][0] <= key and
816
(self._parsed_key_map[index][1] >= key or
817
# end of the file has been parsed
818
self._parsed_byte_map[index][1] == self._size)):
819
result.append(((location, key), False))
821
# no, is the key above or below the probed location:
822
# get the range of the probed & parsed location
823
index = self._parsed_byte_index(location)
824
# if the key is below the start of the range, its below
825
if key < self._parsed_key_map[index][0]:
829
result.append(((location, key), direction))
831
# lookup data to resolve references
832
for location in pending_locations:
834
if location + length > self._size:
835
length = self._size - location
836
# TODO: trim out parsed locations (e.g. if the 800 is into the
837
# parsed region trim it, and dont use the adjust_for_latency
840
readv_ranges.append((location, length))
841
self._read_and_parse(readv_ranges)
842
if self._nodes is not None:
843
# The _read_and_parse triggered a _buffer_all, grab the data and
845
for location, key in pending_references:
846
value, refs = self._nodes[key]
847
result.append(((location, key), (self, key, value, refs)))
849
for location, key in pending_references:
850
# answer key references we had to look-up-late.
851
value, refs = self._bisect_nodes[key]
852
result.append(((location, key), (self, key,
853
value, self._resolve_references(refs))))
856
def _parse_header_from_bytes(self, bytes):
857
"""Parse the header from a region of bytes.
859
:param bytes: The data to parse.
860
:return: An offset, data tuple such as readv yields, for the unparsed
861
data. (which may length 0).
863
signature = bytes[0:len(self._signature())]
864
if not signature == self._signature():
865
raise errors.BadIndexFormatSignature(self._name, GraphIndex)
866
lines = bytes[len(self._signature()):].splitlines()
867
options_line = lines[0]
868
if not options_line.startswith(_OPTION_NODE_REFS):
869
raise errors.BadIndexOptions(self)
871
self.node_ref_lists = int(options_line[len(_OPTION_NODE_REFS):])
873
raise errors.BadIndexOptions(self)
874
options_line = lines[1]
875
if not options_line.startswith(_OPTION_KEY_ELEMENTS):
876
raise errors.BadIndexOptions(self)
878
self._key_length = int(options_line[len(_OPTION_KEY_ELEMENTS):])
880
raise errors.BadIndexOptions(self)
881
options_line = lines[2]
882
if not options_line.startswith(_OPTION_LEN):
883
raise errors.BadIndexOptions(self)
885
self._key_count = int(options_line[len(_OPTION_LEN):])
887
raise errors.BadIndexOptions(self)
888
# calculate the bytes we have processed
889
header_end = (len(signature) + len(lines[0]) + len(lines[1]) +
891
self._parsed_bytes(0, None, header_end, None)
892
# setup parsing state
893
self._expected_elements = 3 + self._key_length
894
# raw data keyed by offset
895
self._keys_by_offset = {}
896
# keys with the value and node references
897
self._bisect_nodes = {}
898
return header_end, bytes[header_end:]
900
def _parse_region(self, offset, data):
901
"""Parse node data returned from a readv operation.
903
:param offset: The byte offset the data starts at.
904
:param data: The data to parse.
908
end = offset + len(data)
911
# Trivial test - if the current index's end is within the
912
# low-matching parsed range, we're done.
913
index = self._parsed_byte_index(high_parsed)
914
if end < self._parsed_byte_map[index][1]:
916
# print "[%d:%d]" % (offset, end), \
917
# self._parsed_byte_map[index:index + 2]
918
high_parsed, last_segment = self._parse_segment(
919
offset, data, end, index)
923
def _parse_segment(self, offset, data, end, index):
924
"""Parse one segment of data.
926
:param offset: Where 'data' begins in the file.
927
:param data: Some data to parse a segment of.
928
:param end: Where data ends
929
:param index: The current index into the parsed bytes map.
930
:return: True if the parsed segment is the last possible one in the
932
:return: high_parsed_byte, last_segment.
933
high_parsed_byte is the location of the highest parsed byte in this
934
segment, last_segment is True if the parsed segment is the last
935
possible one in the data block.
937
# default is to use all data
939
# accomodate overlap with data before this.
940
if offset < self._parsed_byte_map[index][1]:
941
# overlaps the lower parsed region
942
# skip the parsed data
943
trim_start = self._parsed_byte_map[index][1] - offset
944
# don't trim the start for \n
945
start_adjacent = True
946
elif offset == self._parsed_byte_map[index][1]:
947
# abuts the lower parsed region
950
# do not trim anything
951
start_adjacent = True
953
# does not overlap the lower parsed region
956
# but trim the leading \n
957
start_adjacent = False
958
if end == self._size:
959
# lines up to the end of all data:
962
# do not strip to the last \n
965
elif index + 1 == len(self._parsed_byte_map):
966
# at the end of the parsed data
969
# but strip to the last \n
972
elif end == self._parsed_byte_map[index + 1][0]:
973
# buts up against the next parsed region
976
# do not strip to the last \n
979
elif end > self._parsed_byte_map[index + 1][0]:
980
# overlaps into the next parsed region
981
# only consider the unparsed data
982
trim_end = self._parsed_byte_map[index + 1][0] - offset
983
# do not strip to the last \n as we know its an entire record
985
last_segment = end < self._parsed_byte_map[index + 1][1]
987
# does not overlap into the next region
990
# but strip to the last \n
993
# now find bytes to discard if needed
994
if not start_adjacent:
995
# work around python bug in rfind
996
if trim_start is None:
997
trim_start = data.find('\n') + 1
999
trim_start = data.find('\n', trim_start) + 1
1000
if not (trim_start != 0):
1001
raise AssertionError('no \n was present')
1002
# print 'removing start', offset, trim_start, repr(data[:trim_start])
1003
if not end_adjacent:
1004
# work around python bug in rfind
1005
if trim_end is None:
1006
trim_end = data.rfind('\n') + 1
1008
trim_end = data.rfind('\n', None, trim_end) + 1
1009
if not (trim_end != 0):
1010
raise AssertionError('no \n was present')
1011
# print 'removing end', offset, trim_end, repr(data[trim_end:])
1012
# adjust offset and data to the parseable data.
1013
trimmed_data = data[trim_start:trim_end]
1014
if not (trimmed_data):
1015
raise AssertionError('read unneeded data [%d:%d] from [%d:%d]'
1016
% (trim_start, trim_end, offset, offset + len(data)))
1018
offset += trim_start
1019
# print "parsing", repr(trimmed_data)
1020
# splitlines mangles the \r delimiters.. don't use it.
1021
lines = trimmed_data.split('\n')
1024
first_key, last_key, nodes, _ = self._parse_lines(lines, pos)
1025
for key, value in nodes:
1026
self._bisect_nodes[key] = value
1027
self._parsed_bytes(offset, first_key,
1028
offset + len(trimmed_data), last_key)
1029
return offset + len(trimmed_data), last_segment
1031
def _parse_lines(self, lines, pos):
1038
# must be at the end
1040
if not (self._size == pos + 1):
1041
raise AssertionError("%s %s" % (self._size, pos))
1044
elements = line.split('\0')
1045
if len(elements) != self._expected_elements:
1046
raise errors.BadIndexData(self)
1047
# keys are tuples. Each element is a string that may occur many
1048
# times, so we intern them to save space. AB, RC, 200807
1049
key = tuple([intern(element) for element in elements[:self._key_length]])
1050
if first_key is None:
1052
absent, references, value = elements[-3:]
1054
for ref_string in references.split('\t'):
1055
ref_lists.append(tuple([
1056
int(ref) for ref in ref_string.split('\r') if ref
1058
ref_lists = tuple(ref_lists)
1059
self._keys_by_offset[pos] = (key, absent, ref_lists, value)
1060
pos += len(line) + 1 # +1 for the \n
1063
if self.node_ref_lists:
1064
node_value = (value, ref_lists)
1067
nodes.append((key, node_value))
1068
# print "parsed ", key
1069
return first_key, key, nodes, trailers
1071
def _parsed_bytes(self, start, start_key, end, end_key):
1072
"""Mark the bytes from start to end as parsed.
1074
Calling self._parsed_bytes(1,2) will mark one byte (the one at offset
1077
:param start: The start of the parsed region.
1078
:param end: The end of the parsed region.
1080
index = self._parsed_byte_index(start)
1081
new_value = (start, end)
1082
new_key = (start_key, end_key)
1084
# first range parsed is always the beginning.
1085
self._parsed_byte_map.insert(index, new_value)
1086
self._parsed_key_map.insert(index, new_key)
1090
# extend lower region
1091
# extend higher region
1092
# combine two regions
1093
if (index + 1 < len(self._parsed_byte_map) and
1094
self._parsed_byte_map[index][1] == start and
1095
self._parsed_byte_map[index + 1][0] == end):
1096
# combine two regions
1097
self._parsed_byte_map[index] = (self._parsed_byte_map[index][0],
1098
self._parsed_byte_map[index + 1][1])
1099
self._parsed_key_map[index] = (self._parsed_key_map[index][0],
1100
self._parsed_key_map[index + 1][1])
1101
del self._parsed_byte_map[index + 1]
1102
del self._parsed_key_map[index + 1]
1103
elif self._parsed_byte_map[index][1] == start:
1104
# extend the lower entry
1105
self._parsed_byte_map[index] = (
1106
self._parsed_byte_map[index][0], end)
1107
self._parsed_key_map[index] = (
1108
self._parsed_key_map[index][0], end_key)
1109
elif (index + 1 < len(self._parsed_byte_map) and
1110
self._parsed_byte_map[index + 1][0] == end):
1111
# extend the higher entry
1112
self._parsed_byte_map[index + 1] = (
1113
start, self._parsed_byte_map[index + 1][1])
1114
self._parsed_key_map[index + 1] = (
1115
start_key, self._parsed_key_map[index + 1][1])
1118
self._parsed_byte_map.insert(index + 1, new_value)
1119
self._parsed_key_map.insert(index + 1, new_key)
1121
def _read_and_parse(self, readv_ranges):
1122
"""Read the the ranges and parse the resulting data.
1124
:param readv_ranges: A prepared readv range list.
1126
if not readv_ranges:
1128
if self._nodes is None and self._bytes_read * 2 >= self._size:
1129
# We've already read more than 50% of the file and we are about to
1130
# request more data, just _buffer_all() and be done
1134
readv_data = self._transport.readv(self._name, readv_ranges, True,
1137
for offset, data in readv_data:
1138
self._bytes_read += len(data)
1139
if offset == 0 and len(data) == self._size:
1140
# We read the whole range, most likely because the
1141
# Transport upcast our readv ranges into one long request
1142
# for enough total data to grab the whole index.
1143
self._buffer_all(StringIO(data))
1145
if self._bisect_nodes is None:
1146
# this must be the start
1147
if not (offset == 0):
1148
raise AssertionError()
1149
offset, data = self._parse_header_from_bytes(data)
1150
# print readv_ranges, "[%d:%d]" % (offset, offset + len(data))
1151
self._parse_region(offset, data)
1153
def _signature(self):
1154
"""The file signature for this index type."""
1158
"""Validate that everything in the index can be accessed."""
1159
# iter_all validates completely at the moment, so just do that.
1160
for node in self.iter_all_entries():
1164
class CombinedGraphIndex(object):
1165
"""A GraphIndex made up from smaller GraphIndices.
1167
The backing indices must implement GraphIndex, and are presumed to be
1170
Queries against the combined index will be made against the first index,
1171
and then the second and so on. The order of index's can thus influence
1172
performance significantly. For example, if one index is on local disk and a
1173
second on a remote server, the local disk index should be before the other
1177
def __init__(self, indices, reload_func=None):
1178
"""Create a CombinedGraphIndex backed by indices.
1180
:param indices: An ordered list of indices to query for data.
1181
:param reload_func: A function to call if we find we are missing an
1182
index. Should have the form reload_func() => True/False to indicate
1183
if reloading actually changed anything.
1185
self._indices = indices
1186
self._reload_func = reload_func
1190
self.__class__.__name__,
1191
', '.join(map(repr, self._indices)))
1193
def get_parent_map(self, keys):
1194
"""See graph.StackedParentsProvider.get_parent_map"""
1195
search_keys = set(keys)
1196
if NULL_REVISION in search_keys:
1197
search_keys.discard(NULL_REVISION)
1198
found_parents = {NULL_REVISION:[]}
1201
for index, key, value, refs in self.iter_entries(search_keys):
1204
parents = (NULL_REVISION,)
1205
found_parents[key] = parents
1206
return found_parents
1208
has_key = _has_key_from_parent_map
1210
def insert_index(self, pos, index):
1211
"""Insert a new index in the list of indices to query.
1213
:param pos: The position to insert the index.
1214
:param index: The index to insert.
1216
self._indices.insert(pos, index)
1218
def iter_all_entries(self):
1219
"""Iterate over all keys within the index
1221
Duplicate keys across child indices are presumed to have the same
1222
value and are only reported once.
1224
:return: An iterable of (index, key, reference_lists, value).
1225
There is no defined order for the result iteration - it will be in
1226
the most efficient order for the index.
1231
for index in self._indices:
1232
for node in index.iter_all_entries():
1233
if node[1] not in seen_keys:
1235
seen_keys.add(node[1])
1237
except errors.NoSuchFile:
1238
self._reload_or_raise()
1240
def iter_entries(self, keys):
1241
"""Iterate over keys within the index.
1243
Duplicate keys across child indices are presumed to have the same
1244
value and are only reported once.
1246
:param keys: An iterable providing the keys to be retrieved.
1247
:return: An iterable of (index, key, reference_lists, value). There is no
1248
defined order for the result iteration - it will be in the most
1249
efficient order for the index.
1254
for index in self._indices:
1257
for node in index.iter_entries(keys):
1258
keys.remove(node[1])
1261
except errors.NoSuchFile:
1262
self._reload_or_raise()
1264
def iter_entries_prefix(self, keys):
1265
"""Iterate over keys within the index using prefix matching.
1267
Duplicate keys across child indices are presumed to have the same
1268
value and are only reported once.
1270
Prefix matching is applied within the tuple of a key, not to within
1271
the bytestring of each key element. e.g. if you have the keys ('foo',
1272
'bar'), ('foobar', 'gam') and do a prefix search for ('foo', None) then
1273
only the former key is returned.
1275
:param keys: An iterable providing the key prefixes to be retrieved.
1276
Each key prefix takes the form of a tuple the length of a key, but
1277
with the last N elements 'None' rather than a regular bytestring.
1278
The first element cannot be 'None'.
1279
:return: An iterable as per iter_all_entries, but restricted to the
1280
keys with a matching prefix to those supplied. No additional keys
1281
will be returned, and every match that is in the index will be
1290
for index in self._indices:
1291
for node in index.iter_entries_prefix(keys):
1292
if node[1] in seen_keys:
1294
seen_keys.add(node[1])
1297
except errors.NoSuchFile:
1298
self._reload_or_raise()
1300
def key_count(self):
1301
"""Return an estimate of the number of keys in this index.
1303
For CombinedGraphIndex this is approximated by the sum of the keys of
1304
the child indices. As child indices may have duplicate keys this can
1305
have a maximum error of the number of child indices * largest number of
1310
return sum((index.key_count() for index in self._indices), 0)
1311
except errors.NoSuchFile:
1312
self._reload_or_raise()
1314
missing_keys = _missing_keys_from_parent_map
1316
def _reload_or_raise(self):
1317
"""We just got a NoSuchFile exception.
1319
Try to reload the indices, if it fails, just raise the current
1322
if self._reload_func is None:
1324
exc_type, exc_value, exc_traceback = sys.exc_info()
1325
trace.mutter('Trying to reload after getting exception: %s',
1327
if not self._reload_func():
1328
# We tried to reload, but nothing changed, so we fail anyway
1329
trace.mutter('_reload_func indicated nothing has changed.'
1330
' Raising original exception.')
1331
raise exc_type, exc_value, exc_traceback
1334
"""Validate that everything in the index can be accessed."""
1337
for index in self._indices:
1340
except errors.NoSuchFile:
1341
self._reload_or_raise()
1344
class InMemoryGraphIndex(GraphIndexBuilder):
1345
"""A GraphIndex which operates entirely out of memory and is mutable.
1347
This is designed to allow the accumulation of GraphIndex entries during a
1348
single write operation, where the accumulated entries need to be immediately
1349
available - for example via a CombinedGraphIndex.
1352
def add_nodes(self, nodes):
1353
"""Add nodes to the index.
1355
:param nodes: An iterable of (key, node_refs, value) entries to add.
1357
if self.reference_lists:
1358
for (key, value, node_refs) in nodes:
1359
self.add_node(key, value, node_refs)
1361
for (key, value) in nodes:
1362
self.add_node(key, value)
1364
def iter_all_entries(self):
1365
"""Iterate over all keys within the index
1367
:return: An iterable of (index, key, reference_lists, value). There is no
1368
defined order for the result iteration - it will be in the most
1369
efficient order for the index (in this case dictionary hash order).
1371
if 'evil' in debug.debug_flags:
1372
trace.mutter_callsite(3,
1373
"iter_all_entries scales with size of history.")
1374
if self.reference_lists:
1375
for key, (absent, references, value) in self._nodes.iteritems():
1377
yield self, key, value, references
1379
for key, (absent, references, value) in self._nodes.iteritems():
1381
yield self, key, value
1383
def iter_entries(self, keys):
1384
"""Iterate over keys within the index.
1386
:param keys: An iterable providing the keys to be retrieved.
1387
:return: An iterable of (index, key, value, reference_lists). There is no
1388
defined order for the result iteration - it will be in the most
1389
efficient order for the index (keys iteration order in this case).
1392
if self.reference_lists:
1393
for key in keys.intersection(self._keys):
1394
node = self._nodes[key]
1396
yield self, key, node[2], node[1]
1398
for key in keys.intersection(self._keys):
1399
node = self._nodes[key]
1401
yield self, key, node[2]
1403
def iter_entries_prefix(self, keys):
1404
"""Iterate over keys within the index using prefix matching.
1406
Prefix matching is applied within the tuple of a key, not to within
1407
the bytestring of each key element. e.g. if you have the keys ('foo',
1408
'bar'), ('foobar', 'gam') and do a prefix search for ('foo', None) then
1409
only the former key is returned.
1411
:param keys: An iterable providing the key prefixes to be retrieved.
1412
Each key prefix takes the form of a tuple the length of a key, but
1413
with the last N elements 'None' rather than a regular bytestring.
1414
The first element cannot be 'None'.
1415
:return: An iterable as per iter_all_entries, but restricted to the
1416
keys with a matching prefix to those supplied. No additional keys
1417
will be returned, and every match that is in the index will be
1420
# XXX: To much duplication with the GraphIndex class; consider finding
1421
# a good place to pull out the actual common logic.
1425
if self._key_length == 1:
1429
raise errors.BadIndexKey(key)
1430
if len(key) != self._key_length:
1431
raise errors.BadIndexKey(key)
1432
node = self._nodes[key]
1435
if self.reference_lists:
1436
yield self, key, node[2], node[1]
1438
yield self, key, node[2]
1440
nodes_by_key = self._get_nodes_by_key()
1444
raise errors.BadIndexKey(key)
1445
if len(key) != self._key_length:
1446
raise errors.BadIndexKey(key)
1447
# find what it refers to:
1448
key_dict = nodes_by_key
1449
elements = list(key)
1450
# find the subdict to return
1452
while len(elements) and elements[0] is not None:
1453
key_dict = key_dict[elements[0]]
1456
# a non-existant lookup.
1461
key_dict = dicts.pop(-1)
1462
# can't be empty or would not exist
1463
item, value = key_dict.iteritems().next()
1464
if type(value) == dict:
1466
dicts.extend(key_dict.itervalues())
1469
for value in key_dict.itervalues():
1470
yield (self, ) + value
1472
yield (self, ) + key_dict
1474
def key_count(self):
1475
"""Return an estimate of the number of keys in this index.
1477
For InMemoryGraphIndex the estimate is exact.
1479
return len(self._keys)
1482
"""In memory index's have no known corruption at the moment."""
1485
class GraphIndexPrefixAdapter(object):
1486
"""An adapter between GraphIndex with different key lengths.
1488
Queries against this will emit queries against the adapted Graph with the
1489
prefix added, queries for all items use iter_entries_prefix. The returned
1490
nodes will have their keys and node references adjusted to remove the
1491
prefix. Finally, an add_nodes_callback can be supplied - when called the
1492
nodes and references being added will have prefix prepended.
1495
def __init__(self, adapted, prefix, missing_key_length,
1496
add_nodes_callback=None):
1497
"""Construct an adapter against adapted with prefix."""
1498
self.adapted = adapted
1499
self.prefix_key = prefix + (None,)*missing_key_length
1500
self.prefix = prefix
1501
self.prefix_len = len(prefix)
1502
self.add_nodes_callback = add_nodes_callback
1504
def add_nodes(self, nodes):
1505
"""Add nodes to the index.
1507
:param nodes: An iterable of (key, node_refs, value) entries to add.
1509
# save nodes in case its an iterator
1510
nodes = tuple(nodes)
1511
translated_nodes = []
1513
# Add prefix_key to each reference node_refs is a tuple of tuples,
1514
# so split it apart, and add prefix_key to the internal reference
1515
for (key, value, node_refs) in nodes:
1516
adjusted_references = (
1517
tuple(tuple(self.prefix + ref_node for ref_node in ref_list)
1518
for ref_list in node_refs))
1519
translated_nodes.append((self.prefix + key, value,
1520
adjusted_references))
1522
# XXX: TODO add an explicit interface for getting the reference list
1523
# status, to handle this bit of user-friendliness in the API more
1525
for (key, value) in nodes:
1526
translated_nodes.append((self.prefix + key, value))
1527
self.add_nodes_callback(translated_nodes)
1529
def add_node(self, key, value, references=()):
1530
"""Add a node to the index.
1532
:param key: The key. keys are non-empty tuples containing
1533
as many whitespace-free utf8 bytestrings as the key length
1534
defined for this index.
1535
:param references: An iterable of iterables of keys. Each is a
1536
reference to another key.
1537
:param value: The value to associate with the key. It may be any
1538
bytes as long as it does not contain \0 or \n.
1540
self.add_nodes(((key, value, references), ))
1542
def _strip_prefix(self, an_iter):
1543
"""Strip prefix data from nodes and return it."""
1544
for node in an_iter:
1546
if node[1][:self.prefix_len] != self.prefix:
1547
raise errors.BadIndexData(self)
1548
for ref_list in node[3]:
1549
for ref_node in ref_list:
1550
if ref_node[:self.prefix_len] != self.prefix:
1551
raise errors.BadIndexData(self)
1552
yield node[0], node[1][self.prefix_len:], node[2], (
1553
tuple(tuple(ref_node[self.prefix_len:] for ref_node in ref_list)
1554
for ref_list in node[3]))
1556
def iter_all_entries(self):
1557
"""Iterate over all keys within the index
1559
iter_all_entries is implemented against the adapted index using
1560
iter_entries_prefix.
1562
:return: An iterable of (index, key, reference_lists, value). There is no
1563
defined order for the result iteration - it will be in the most
1564
efficient order for the index (in this case dictionary hash order).
1566
return self._strip_prefix(self.adapted.iter_entries_prefix([self.prefix_key]))
1568
def iter_entries(self, keys):
1569
"""Iterate over keys within the index.
1571
:param keys: An iterable providing the keys to be retrieved.
1572
:return: An iterable of (index, key, value, reference_lists). There is no
1573
defined order for the result iteration - it will be in the most
1574
efficient order for the index (keys iteration order in this case).
1576
return self._strip_prefix(self.adapted.iter_entries(
1577
self.prefix + key for key in keys))
1579
def iter_entries_prefix(self, keys):
1580
"""Iterate over keys within the index using prefix matching.
1582
Prefix matching is applied within the tuple of a key, not to within
1583
the bytestring of each key element. e.g. if you have the keys ('foo',
1584
'bar'), ('foobar', 'gam') and do a prefix search for ('foo', None) then
1585
only the former key is returned.
1587
:param keys: An iterable providing the key prefixes to be retrieved.
1588
Each key prefix takes the form of a tuple the length of a key, but
1589
with the last N elements 'None' rather than a regular bytestring.
1590
The first element cannot be 'None'.
1591
:return: An iterable as per iter_all_entries, but restricted to the
1592
keys with a matching prefix to those supplied. No additional keys
1593
will be returned, and every match that is in the index will be
1596
return self._strip_prefix(self.adapted.iter_entries_prefix(
1597
self.prefix + key for key in keys))
1599
def key_count(self):
1600
"""Return an estimate of the number of keys in this index.
1602
For GraphIndexPrefixAdapter this is relatively expensive - key
1603
iteration with the prefix is done.
1605
return len(list(self.iter_all_entries()))
1608
"""Call the adapted's validate."""
1609
self.adapted.validate()
added
removed
bzrlib/index.py
