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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., 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 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
667
yield self, key, self._nodes[key]
669
nodes_by_key = self._get_nodes_by_key()
673
raise errors.BadIndexKey(key)
674
if len(key) != self._key_length:
675
raise errors.BadIndexKey(key)
676
# find what it refers to:
677
key_dict = nodes_by_key
679
# find the subdict whose contents should be returned.
681
while len(elements) and elements[0] is not None:
682
key_dict = key_dict[elements[0]]
685
# a non-existant lookup.
690
key_dict = dicts.pop(-1)
691
# can't be empty or would not exist
692
item, value = key_dict.iteritems().next()
693
if type(value) == dict:
695
dicts.extend(key_dict.itervalues())
698
for value in key_dict.itervalues():
699
# each value is the key:value:node refs tuple
701
yield (self, ) + value
703
# the last thing looked up was a terminal element
704
yield (self, ) + key_dict
707
"""Return an estimate of the number of keys in this index.
709
For GraphIndex the estimate is exact.
711
if self._key_count is None:
712
self._read_and_parse([_HEADER_READV])
713
return self._key_count
715
def _lookup_keys_via_location(self, location_keys):
716
"""Public interface for implementing bisection.
718
If _buffer_all has been called, then all the data for the index is in
719
memory, and this method should not be called, as it uses a separate
720
cache because it cannot pre-resolve all indices, which buffer_all does
723
:param location_keys: A list of location(byte offset), key tuples.
724
:return: A list of (location_key, result) tuples as expected by
725
bzrlib.bisect_multi.bisect_multi_bytes.
727
# Possible improvements:
728
# - only bisect lookup each key once
729
# - sort the keys first, and use that to reduce the bisection window
731
# this progresses in three parts:
734
# attempt to answer the question from the now in memory data.
735
# build the readv request
736
# for each location, ask for 800 bytes - much more than rows we've seen
739
for location, key in location_keys:
740
# can we answer from cache?
741
if self._bisect_nodes and key in self._bisect_nodes:
742
# We have the key parsed.
744
index = self._parsed_key_index(key)
745
if (len(self._parsed_key_map) and
746
self._parsed_key_map[index][0] <= key and
747
(self._parsed_key_map[index][1] >= key or
748
# end of the file has been parsed
749
self._parsed_byte_map[index][1] == self._size)):
750
# the key has been parsed, so no lookup is needed even if its
753
# - if we have examined this part of the file already - yes
754
index = self._parsed_byte_index(location)
755
if (len(self._parsed_byte_map) and
756
self._parsed_byte_map[index][0] <= location and
757
self._parsed_byte_map[index][1] > location):
758
# the byte region has been parsed, so no read is needed.
761
if location + length > self._size:
762
length = self._size - location
763
# todo, trim out parsed locations.
765
readv_ranges.append((location, length))
766
# read the header if needed
767
if self._bisect_nodes is None:
768
readv_ranges.append(_HEADER_READV)
769
self._read_and_parse(readv_ranges)
771
if self._nodes is not None:
772
# _read_and_parse triggered a _buffer_all because we requested the
774
for location, key in location_keys:
775
if key not in self._nodes: # not present
776
result.append(((location, key), False))
777
elif self.node_ref_lists:
778
value, refs = self._nodes[key]
779
result.append(((location, key),
780
(self, key, value, refs)))
782
result.append(((location, key),
783
(self, key, self._nodes[key])))
786
# - figure out <, >, missing, present
787
# - result present references so we can return them.
788
# keys that we cannot answer until we resolve references
789
pending_references = []
790
pending_locations = set()
791
for location, key in location_keys:
792
# can we answer from cache?
793
if key in self._bisect_nodes:
794
# the key has been parsed, so no lookup is needed
795
if self.node_ref_lists:
796
# the references may not have been all parsed.
797
value, refs = self._bisect_nodes[key]
798
wanted_locations = []
799
for ref_list in refs:
801
if ref not in self._keys_by_offset:
802
wanted_locations.append(ref)
804
pending_locations.update(wanted_locations)
805
pending_references.append((location, key))
807
result.append(((location, key), (self, key,
808
value, self._resolve_references(refs))))
810
result.append(((location, key),
811
(self, key, self._bisect_nodes[key])))
814
# has the region the key should be in, been parsed?
815
index = self._parsed_key_index(key)
816
if (self._parsed_key_map[index][0] <= key and
817
(self._parsed_key_map[index][1] >= key or
818
# end of the file has been parsed
819
self._parsed_byte_map[index][1] == self._size)):
820
result.append(((location, key), False))
822
# no, is the key above or below the probed location:
823
# get the range of the probed & parsed location
824
index = self._parsed_byte_index(location)
825
# if the key is below the start of the range, its below
826
if key < self._parsed_key_map[index][0]:
830
result.append(((location, key), direction))
832
# lookup data to resolve references
833
for location in pending_locations:
835
if location + length > self._size:
836
length = self._size - location
837
# TODO: trim out parsed locations (e.g. if the 800 is into the
838
# parsed region trim it, and dont use the adjust_for_latency
841
readv_ranges.append((location, length))
842
self._read_and_parse(readv_ranges)
843
if self._nodes is not None:
844
# The _read_and_parse triggered a _buffer_all, grab the data and
846
for location, key in pending_references:
847
value, refs = self._nodes[key]
848
result.append(((location, key), (self, key, value, refs)))
850
for location, key in pending_references:
851
# answer key references we had to look-up-late.
852
value, refs = self._bisect_nodes[key]
853
result.append(((location, key), (self, key,
854
value, self._resolve_references(refs))))
857
def _parse_header_from_bytes(self, bytes):
858
"""Parse the header from a region of bytes.
860
:param bytes: The data to parse.
861
:return: An offset, data tuple such as readv yields, for the unparsed
862
data. (which may length 0).
864
signature = bytes[0:len(self._signature())]
865
if not signature == self._signature():
866
raise errors.BadIndexFormatSignature(self._name, GraphIndex)
867
lines = bytes[len(self._signature()):].splitlines()
868
options_line = lines[0]
869
if not options_line.startswith(_OPTION_NODE_REFS):
870
raise errors.BadIndexOptions(self)
872
self.node_ref_lists = int(options_line[len(_OPTION_NODE_REFS):])
874
raise errors.BadIndexOptions(self)
875
options_line = lines[1]
876
if not options_line.startswith(_OPTION_KEY_ELEMENTS):
877
raise errors.BadIndexOptions(self)
879
self._key_length = int(options_line[len(_OPTION_KEY_ELEMENTS):])
881
raise errors.BadIndexOptions(self)
882
options_line = lines[2]
883
if not options_line.startswith(_OPTION_LEN):
884
raise errors.BadIndexOptions(self)
886
self._key_count = int(options_line[len(_OPTION_LEN):])
888
raise errors.BadIndexOptions(self)
889
# calculate the bytes we have processed
890
header_end = (len(signature) + len(lines[0]) + len(lines[1]) +
892
self._parsed_bytes(0, None, header_end, None)
893
# setup parsing state
894
self._expected_elements = 3 + self._key_length
895
# raw data keyed by offset
896
self._keys_by_offset = {}
897
# keys with the value and node references
898
self._bisect_nodes = {}
899
return header_end, bytes[header_end:]
901
def _parse_region(self, offset, data):
902
"""Parse node data returned from a readv operation.
904
:param offset: The byte offset the data starts at.
905
:param data: The data to parse.
909
end = offset + len(data)
912
# Trivial test - if the current index's end is within the
913
# low-matching parsed range, we're done.
914
index = self._parsed_byte_index(high_parsed)
915
if end < self._parsed_byte_map[index][1]:
917
# print "[%d:%d]" % (offset, end), \
918
# self._parsed_byte_map[index:index + 2]
919
high_parsed, last_segment = self._parse_segment(
920
offset, data, end, index)
924
def _parse_segment(self, offset, data, end, index):
925
"""Parse one segment of data.
927
:param offset: Where 'data' begins in the file.
928
:param data: Some data to parse a segment of.
929
:param end: Where data ends
930
:param index: The current index into the parsed bytes map.
931
:return: True if the parsed segment is the last possible one in the
933
:return: high_parsed_byte, last_segment.
934
high_parsed_byte is the location of the highest parsed byte in this
935
segment, last_segment is True if the parsed segment is the last
936
possible one in the data block.
938
# default is to use all data
940
# accomodate overlap with data before this.
941
if offset < self._parsed_byte_map[index][1]:
942
# overlaps the lower parsed region
943
# skip the parsed data
944
trim_start = self._parsed_byte_map[index][1] - offset
945
# don't trim the start for \n
946
start_adjacent = True
947
elif offset == self._parsed_byte_map[index][1]:
948
# abuts the lower parsed region
951
# do not trim anything
952
start_adjacent = True
954
# does not overlap the lower parsed region
957
# but trim the leading \n
958
start_adjacent = False
959
if end == self._size:
960
# lines up to the end of all data:
963
# do not strip to the last \n
966
elif index + 1 == len(self._parsed_byte_map):
967
# at the end of the parsed data
970
# but strip to the last \n
973
elif end == self._parsed_byte_map[index + 1][0]:
974
# buts up against the next parsed region
977
# do not strip to the last \n
980
elif end > self._parsed_byte_map[index + 1][0]:
981
# overlaps into the next parsed region
982
# only consider the unparsed data
983
trim_end = self._parsed_byte_map[index + 1][0] - offset
984
# do not strip to the last \n as we know its an entire record
986
last_segment = end < self._parsed_byte_map[index + 1][1]
988
# does not overlap into the next region
991
# but strip to the last \n
994
# now find bytes to discard if needed
995
if not start_adjacent:
996
# work around python bug in rfind
997
if trim_start is None:
998
trim_start = data.find('\n') + 1
1000
trim_start = data.find('\n', trim_start) + 1
1001
if not (trim_start != 0):
1002
raise AssertionError('no \n was present')
1003
# print 'removing start', offset, trim_start, repr(data[:trim_start])
1004
if not end_adjacent:
1005
# work around python bug in rfind
1006
if trim_end is None:
1007
trim_end = data.rfind('\n') + 1
1009
trim_end = data.rfind('\n', None, trim_end) + 1
1010
if not (trim_end != 0):
1011
raise AssertionError('no \n was present')
1012
# print 'removing end', offset, trim_end, repr(data[trim_end:])
1013
# adjust offset and data to the parseable data.
1014
trimmed_data = data[trim_start:trim_end]
1015
if not (trimmed_data):
1016
raise AssertionError('read unneeded data [%d:%d] from [%d:%d]'
1017
% (trim_start, trim_end, offset, offset + len(data)))
1019
offset += trim_start
1020
# print "parsing", repr(trimmed_data)
1021
# splitlines mangles the \r delimiters.. don't use it.
1022
lines = trimmed_data.split('\n')
1025
first_key, last_key, nodes, _ = self._parse_lines(lines, pos)
1026
for key, value in nodes:
1027
self._bisect_nodes[key] = value
1028
self._parsed_bytes(offset, first_key,
1029
offset + len(trimmed_data), last_key)
1030
return offset + len(trimmed_data), last_segment
1032
def _parse_lines(self, lines, pos):
1039
# must be at the end
1041
if not (self._size == pos + 1):
1042
raise AssertionError("%s %s" % (self._size, pos))
1045
elements = line.split('\0')
1046
if len(elements) != self._expected_elements:
1047
raise errors.BadIndexData(self)
1048
# keys are tuples. Each element is a string that may occur many
1049
# times, so we intern them to save space. AB, RC, 200807
1050
key = tuple([intern(element) for element in elements[:self._key_length]])
1051
if first_key is None:
1053
absent, references, value = elements[-3:]
1055
for ref_string in references.split('\t'):
1056
ref_lists.append(tuple([
1057
int(ref) for ref in ref_string.split('\r') if ref
1059
ref_lists = tuple(ref_lists)
1060
self._keys_by_offset[pos] = (key, absent, ref_lists, value)
1061
pos += len(line) + 1 # +1 for the \n
1064
if self.node_ref_lists:
1065
node_value = (value, ref_lists)
1068
nodes.append((key, node_value))
1069
# print "parsed ", key
1070
return first_key, key, nodes, trailers
1072
def _parsed_bytes(self, start, start_key, end, end_key):
1073
"""Mark the bytes from start to end as parsed.
1075
Calling self._parsed_bytes(1,2) will mark one byte (the one at offset
1078
:param start: The start of the parsed region.
1079
:param end: The end of the parsed region.
1081
index = self._parsed_byte_index(start)
1082
new_value = (start, end)
1083
new_key = (start_key, end_key)
1085
# first range parsed is always the beginning.
1086
self._parsed_byte_map.insert(index, new_value)
1087
self._parsed_key_map.insert(index, new_key)
1091
# extend lower region
1092
# extend higher region
1093
# combine two regions
1094
if (index + 1 < len(self._parsed_byte_map) and
1095
self._parsed_byte_map[index][1] == start and
1096
self._parsed_byte_map[index + 1][0] == end):
1097
# combine two regions
1098
self._parsed_byte_map[index] = (self._parsed_byte_map[index][0],
1099
self._parsed_byte_map[index + 1][1])
1100
self._parsed_key_map[index] = (self._parsed_key_map[index][0],
1101
self._parsed_key_map[index + 1][1])
1102
del self._parsed_byte_map[index + 1]
1103
del self._parsed_key_map[index + 1]
1104
elif self._parsed_byte_map[index][1] == start:
1105
# extend the lower entry
1106
self._parsed_byte_map[index] = (
1107
self._parsed_byte_map[index][0], end)
1108
self._parsed_key_map[index] = (
1109
self._parsed_key_map[index][0], end_key)
1110
elif (index + 1 < len(self._parsed_byte_map) and
1111
self._parsed_byte_map[index + 1][0] == end):
1112
# extend the higher entry
1113
self._parsed_byte_map[index + 1] = (
1114
start, self._parsed_byte_map[index + 1][1])
1115
self._parsed_key_map[index + 1] = (
1116
start_key, self._parsed_key_map[index + 1][1])
1119
self._parsed_byte_map.insert(index + 1, new_value)
1120
self._parsed_key_map.insert(index + 1, new_key)
1122
def _read_and_parse(self, readv_ranges):
1123
"""Read the the ranges and parse the resulting data.
1125
:param readv_ranges: A prepared readv range list.
1127
if not readv_ranges:
1129
if self._nodes is None and self._bytes_read * 2 >= self._size:
1130
# We've already read more than 50% of the file and we are about to
1131
# request more data, just _buffer_all() and be done
1135
readv_data = self._transport.readv(self._name, readv_ranges, True,
1138
for offset, data in readv_data:
1139
self._bytes_read += len(data)
1140
if offset == 0 and len(data) == self._size:
1141
# We read the whole range, most likely because the
1142
# Transport upcast our readv ranges into one long request
1143
# for enough total data to grab the whole index.
1144
self._buffer_all(StringIO(data))
1146
if self._bisect_nodes is None:
1147
# this must be the start
1148
if not (offset == 0):
1149
raise AssertionError()
1150
offset, data = self._parse_header_from_bytes(data)
1151
# print readv_ranges, "[%d:%d]" % (offset, offset + len(data))
1152
self._parse_region(offset, data)
1154
def _signature(self):
1155
"""The file signature for this index type."""
1159
"""Validate that everything in the index can be accessed."""
1160
# iter_all validates completely at the moment, so just do that.
1161
for node in self.iter_all_entries():
1165
class CombinedGraphIndex(object):
1166
"""A GraphIndex made up from smaller GraphIndices.
1168
The backing indices must implement GraphIndex, and are presumed to be
1171
Queries against the combined index will be made against the first index,
1172
and then the second and so on. The order of index's can thus influence
1173
performance significantly. For example, if one index is on local disk and a
1174
second on a remote server, the local disk index should be before the other
1178
def __init__(self, indices, reload_func=None):
1179
"""Create a CombinedGraphIndex backed by indices.
1181
:param indices: An ordered list of indices to query for data.
1182
:param reload_func: A function to call if we find we are missing an
1183
index. Should have the form reload_func() => True/False to indicate
1184
if reloading actually changed anything.
1186
self._indices = indices
1187
self._reload_func = reload_func
1191
self.__class__.__name__,
1192
', '.join(map(repr, self._indices)))
1194
@symbol_versioning.deprecated_method(symbol_versioning.one_one)
1195
def get_parents(self, revision_ids):
1196
"""See graph._StackedParentsProvider.get_parents.
1198
This implementation thunks the graph.Graph.get_parents api across to
1201
:param revision_ids: An iterable of graph keys for this graph.
1202
:return: A list of parent details for each key in revision_ids.
1203
Each parent details will be one of:
1204
* None when the key was missing
1205
* (NULL_REVISION,) when the key has no parents.
1206
* (parent_key, parent_key...) otherwise.
1208
parent_map = self.get_parent_map(revision_ids)
1209
return [parent_map.get(r, None) for r in revision_ids]
1211
def get_parent_map(self, keys):
1212
"""See graph._StackedParentsProvider.get_parent_map"""
1213
search_keys = set(keys)
1214
if NULL_REVISION in search_keys:
1215
search_keys.discard(NULL_REVISION)
1216
found_parents = {NULL_REVISION:[]}
1219
for index, key, value, refs in self.iter_entries(search_keys):
1222
parents = (NULL_REVISION,)
1223
found_parents[key] = parents
1224
return found_parents
1226
has_key = _has_key_from_parent_map
1228
def insert_index(self, pos, index):
1229
"""Insert a new index in the list of indices to query.
1231
:param pos: The position to insert the index.
1232
:param index: The index to insert.
1234
self._indices.insert(pos, index)
1236
def iter_all_entries(self):
1237
"""Iterate over all keys within the index
1239
Duplicate keys across child indices are presumed to have the same
1240
value and are only reported once.
1242
:return: An iterable of (index, key, reference_lists, value).
1243
There is no defined order for the result iteration - it will be in
1244
the most efficient order for the index.
1249
for index in self._indices:
1250
for node in index.iter_all_entries():
1251
if node[1] not in seen_keys:
1253
seen_keys.add(node[1])
1255
except errors.NoSuchFile:
1256
self._reload_or_raise()
1258
def iter_entries(self, keys):
1259
"""Iterate over keys within the index.
1261
Duplicate keys across child indices are presumed to have the same
1262
value and are only reported once.
1264
:param keys: An iterable providing the keys to be retrieved.
1265
:return: An iterable of (index, key, reference_lists, value). There is no
1266
defined order for the result iteration - it will be in the most
1267
efficient order for the index.
1272
for index in self._indices:
1275
for node in index.iter_entries(keys):
1276
keys.remove(node[1])
1279
except errors.NoSuchFile:
1280
self._reload_or_raise()
1282
def iter_entries_prefix(self, keys):
1283
"""Iterate over keys within the index using prefix matching.
1285
Duplicate keys across child indices are presumed to have the same
1286
value and are only reported once.
1288
Prefix matching is applied within the tuple of a key, not to within
1289
the bytestring of each key element. e.g. if you have the keys ('foo',
1290
'bar'), ('foobar', 'gam') and do a prefix search for ('foo', None) then
1291
only the former key is returned.
1293
:param keys: An iterable providing the key prefixes to be retrieved.
1294
Each key prefix takes the form of a tuple the length of a key, but
1295
with the last N elements 'None' rather than a regular bytestring.
1296
The first element cannot be 'None'.
1297
:return: An iterable as per iter_all_entries, but restricted to the
1298
keys with a matching prefix to those supplied. No additional keys
1299
will be returned, and every match that is in the index will be
1308
for index in self._indices:
1309
for node in index.iter_entries_prefix(keys):
1310
if node[1] in seen_keys:
1312
seen_keys.add(node[1])
1315
except errors.NoSuchFile:
1316
self._reload_or_raise()
1318
def key_count(self):
1319
"""Return an estimate of the number of keys in this index.
1321
For CombinedGraphIndex this is approximated by the sum of the keys of
1322
the child indices. As child indices may have duplicate keys this can
1323
have a maximum error of the number of child indices * largest number of
1328
return sum((index.key_count() for index in self._indices), 0)
1329
except errors.NoSuchFile:
1330
self._reload_or_raise()
1332
missing_keys = _missing_keys_from_parent_map
1334
def _reload_or_raise(self):
1335
"""We just got a NoSuchFile exception.
1337
Try to reload the indices, if it fails, just raise the current
1340
if self._reload_func is None:
1342
exc_type, exc_value, exc_traceback = sys.exc_info()
1343
trace.mutter('Trying to reload after getting exception: %s',
1345
if not self._reload_func():
1346
# We tried to reload, but nothing changed, so we fail anyway
1347
trace.mutter('_reload_func indicated nothing has changed.'
1348
' Raising original exception.')
1349
raise exc_type, exc_value, exc_traceback
1352
"""Validate that everything in the index can be accessed."""
1355
for index in self._indices:
1358
except errors.NoSuchFile:
1359
self._reload_or_raise()
1362
class InMemoryGraphIndex(GraphIndexBuilder):
1363
"""A GraphIndex which operates entirely out of memory and is mutable.
1365
This is designed to allow the accumulation of GraphIndex entries during a
1366
single write operation, where the accumulated entries need to be immediately
1367
available - for example via a CombinedGraphIndex.
1370
def add_nodes(self, nodes):
1371
"""Add nodes to the index.
1373
:param nodes: An iterable of (key, node_refs, value) entries to add.
1375
if self.reference_lists:
1376
for (key, value, node_refs) in nodes:
1377
self.add_node(key, value, node_refs)
1379
for (key, value) in nodes:
1380
self.add_node(key, value)
1382
def iter_all_entries(self):
1383
"""Iterate over all keys within the index
1385
:return: An iterable of (index, key, reference_lists, value). There is no
1386
defined order for the result iteration - it will be in the most
1387
efficient order for the index (in this case dictionary hash order).
1389
if 'evil' in debug.debug_flags:
1390
trace.mutter_callsite(3,
1391
"iter_all_entries scales with size of history.")
1392
if self.reference_lists:
1393
for key, (absent, references, value) in self._nodes.iteritems():
1395
yield self, key, value, references
1397
for key, (absent, references, value) in self._nodes.iteritems():
1399
yield self, key, value
1401
def iter_entries(self, keys):
1402
"""Iterate over keys within the index.
1404
:param keys: An iterable providing the keys to be retrieved.
1405
:return: An iterable of (index, key, value, reference_lists). There is no
1406
defined order for the result iteration - it will be in the most
1407
efficient order for the index (keys iteration order in this case).
1410
if self.reference_lists:
1411
for key in keys.intersection(self._keys):
1412
node = self._nodes[key]
1414
yield self, key, node[2], node[1]
1416
for key in keys.intersection(self._keys):
1417
node = self._nodes[key]
1419
yield self, key, node[2]
1421
def iter_entries_prefix(self, keys):
1422
"""Iterate over keys within the index using prefix matching.
1424
Prefix matching is applied within the tuple of a key, not to within
1425
the bytestring of each key element. e.g. if you have the keys ('foo',
1426
'bar'), ('foobar', 'gam') and do a prefix search for ('foo', None) then
1427
only the former key is returned.
1429
:param keys: An iterable providing the key prefixes to be retrieved.
1430
Each key prefix takes the form of a tuple the length of a key, but
1431
with the last N elements 'None' rather than a regular bytestring.
1432
The first element cannot be 'None'.
1433
:return: An iterable as per iter_all_entries, but restricted to the
1434
keys with a matching prefix to those supplied. No additional keys
1435
will be returned, and every match that is in the index will be
1438
# XXX: To much duplication with the GraphIndex class; consider finding
1439
# a good place to pull out the actual common logic.
1443
if self._key_length == 1:
1447
raise errors.BadIndexKey(key)
1448
if len(key) != self._key_length:
1449
raise errors.BadIndexKey(key)
1450
node = self._nodes[key]
1453
if self.reference_lists:
1454
yield self, key, node[2], node[1]
1456
yield self, key, node[2]
1458
nodes_by_key = self._get_nodes_by_key()
1462
raise errors.BadIndexKey(key)
1463
if len(key) != self._key_length:
1464
raise errors.BadIndexKey(key)
1465
# find what it refers to:
1466
key_dict = nodes_by_key
1467
elements = list(key)
1468
# find the subdict to return
1470
while len(elements) and elements[0] is not None:
1471
key_dict = key_dict[elements[0]]
1474
# a non-existant lookup.
1479
key_dict = dicts.pop(-1)
1480
# can't be empty or would not exist
1481
item, value = key_dict.iteritems().next()
1482
if type(value) == dict:
1484
dicts.extend(key_dict.itervalues())
1487
for value in key_dict.itervalues():
1488
yield (self, ) + value
1490
yield (self, ) + key_dict
1492
def key_count(self):
1493
"""Return an estimate of the number of keys in this index.
1495
For InMemoryGraphIndex the estimate is exact.
1497
return len(self._keys)
1500
"""In memory index's have no known corruption at the moment."""
1503
class GraphIndexPrefixAdapter(object):
1504
"""An adapter between GraphIndex with different key lengths.
1506
Queries against this will emit queries against the adapted Graph with the
1507
prefix added, queries for all items use iter_entries_prefix. The returned
1508
nodes will have their keys and node references adjusted to remove the
1509
prefix. Finally, an add_nodes_callback can be supplied - when called the
1510
nodes and references being added will have prefix prepended.
1513
def __init__(self, adapted, prefix, missing_key_length,
1514
add_nodes_callback=None):
1515
"""Construct an adapter against adapted with prefix."""
1516
self.adapted = adapted
1517
self.prefix_key = prefix + (None,)*missing_key_length
1518
self.prefix = prefix
1519
self.prefix_len = len(prefix)
1520
self.add_nodes_callback = add_nodes_callback
1522
def add_nodes(self, nodes):
1523
"""Add nodes to the index.
1525
:param nodes: An iterable of (key, node_refs, value) entries to add.
1527
# save nodes in case its an iterator
1528
nodes = tuple(nodes)
1529
translated_nodes = []
1531
# Add prefix_key to each reference node_refs is a tuple of tuples,
1532
# so split it apart, and add prefix_key to the internal reference
1533
for (key, value, node_refs) in nodes:
1534
adjusted_references = (
1535
tuple(tuple(self.prefix + ref_node for ref_node in ref_list)
1536
for ref_list in node_refs))
1537
translated_nodes.append((self.prefix + key, value,
1538
adjusted_references))
1540
# XXX: TODO add an explicit interface for getting the reference list
1541
# status, to handle this bit of user-friendliness in the API more
1543
for (key, value) in nodes:
1544
translated_nodes.append((self.prefix + key, value))
1545
self.add_nodes_callback(translated_nodes)
1547
def add_node(self, key, value, references=()):
1548
"""Add a node to the index.
1550
:param key: The key. keys are non-empty tuples containing
1551
as many whitespace-free utf8 bytestrings as the key length
1552
defined for this index.
1553
:param references: An iterable of iterables of keys. Each is a
1554
reference to another key.
1555
:param value: The value to associate with the key. It may be any
1556
bytes as long as it does not contain \0 or \n.
1558
self.add_nodes(((key, value, references), ))
1560
def _strip_prefix(self, an_iter):
1561
"""Strip prefix data from nodes and return it."""
1562
for node in an_iter:
1564
if node[1][:self.prefix_len] != self.prefix:
1565
raise errors.BadIndexData(self)
1566
for ref_list in node[3]:
1567
for ref_node in ref_list:
1568
if ref_node[:self.prefix_len] != self.prefix:
1569
raise errors.BadIndexData(self)
1570
yield node[0], node[1][self.prefix_len:], node[2], (
1571
tuple(tuple(ref_node[self.prefix_len:] for ref_node in ref_list)
1572
for ref_list in node[3]))
1574
def iter_all_entries(self):
1575
"""Iterate over all keys within the index
1577
iter_all_entries is implemented against the adapted index using
1578
iter_entries_prefix.
1580
:return: An iterable of (index, key, reference_lists, value). There is no
1581
defined order for the result iteration - it will be in the most
1582
efficient order for the index (in this case dictionary hash order).
1584
return self._strip_prefix(self.adapted.iter_entries_prefix([self.prefix_key]))
1586
def iter_entries(self, keys):
1587
"""Iterate over keys within the index.
1589
:param keys: An iterable providing the keys to be retrieved.
1590
:return: An iterable of (index, key, value, reference_lists). There is no
1591
defined order for the result iteration - it will be in the most
1592
efficient order for the index (keys iteration order in this case).
1594
return self._strip_prefix(self.adapted.iter_entries(
1595
self.prefix + key for key in keys))
1597
def iter_entries_prefix(self, keys):
1598
"""Iterate over keys within the index using prefix matching.
1600
Prefix matching is applied within the tuple of a key, not to within
1601
the bytestring of each key element. e.g. if you have the keys ('foo',
1602
'bar'), ('foobar', 'gam') and do a prefix search for ('foo', None) then
1603
only the former key is returned.
1605
:param keys: An iterable providing the key prefixes to be retrieved.
1606
Each key prefix takes the form of a tuple the length of a key, but
1607
with the last N elements 'None' rather than a regular bytestring.
1608
The first element cannot be 'None'.
1609
:return: An iterable as per iter_all_entries, but restricted to the
1610
keys with a matching prefix to those supplied. No additional keys
1611
will be returned, and every match that is in the index will be
1614
return self._strip_prefix(self.adapted.iter_entries_prefix(
1615
self.prefix + key for key in keys))
1617
def key_count(self):
1618
"""Return an estimate of the number of keys in this index.
1620
For GraphIndexPrefixAdapter this is relatively expensive - key
1621
iteration with the prefix is done.
1623
return len(list(self.iter_all_entries()))
1626
"""Call the adapted's validate."""
1627
self.adapted.validate()
added
removed
bzrlib/index.py
