# Copyright (C) 2008, One Laptop Per Child # # This program is free software; you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation; either version 2 of the License, or # (at your option) any later version. # # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program; if not, write to the Free Software # Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA import logging import os import sys import gobject import xapian from xapian import WritableDatabase, Document, Enquire, Query from carquinyol import layoutmanager from carquinyol.layoutmanager import MAX_QUERY_LIMIT _VALUE_UID = 0 _VALUE_TIMESTAMP = 1 _VALUE_TITLE = 2 # 3 reserved for version support _VALUE_FILESIZE = 4 _VALUE_CREATION_TIME = 5 _PREFIX_NONE = 'N' _PREFIX_FULL_VALUE = 'F' _PREFIX_UID = 'Q' _PREFIX_ACTIVITY = 'A' _PREFIX_ACTIVITY_ID = 'I' _PREFIX_MIME_TYPE = 'M' _PREFIX_KEEP = 'K' # Force a flush every _n_ changes to the db _FLUSH_THRESHOLD = 20 # Force a flush after _n_ seconds since the last change to the db _FLUSH_TIMEOUT = 5 _PROPERTIES_NOT_TO_INDEX = ['timestamp', 'preview'] _MAX_RESULTS = int(2 ** 31 - 1) _QUERY_TERM_MAP = { 'uid': _PREFIX_UID, 'activity': _PREFIX_ACTIVITY, 'activity_id': _PREFIX_ACTIVITY_ID, 'mime_type': _PREFIX_MIME_TYPE, 'keep': _PREFIX_KEEP, } _QUERY_VALUE_MAP = { 'timestamp': {'number': _VALUE_TIMESTAMP, 'type': float}, 'filesize': {'number': _VALUE_FILESIZE, 'type': int}, 'creation_time': {'number': _VALUE_CREATION_TIME, 'type': float}, } class TermGenerator (xapian.TermGenerator): def index_document(self, document, properties): document.add_value(_VALUE_TIMESTAMP, xapian.sortable_serialise(float(properties['timestamp']))) document.add_value(_VALUE_TITLE, properties.get('title', '').strip()) if 'filesize' in properties: try: document.add_value(_VALUE_FILESIZE, xapian.sortable_serialise(int(properties['filesize']))) except (ValueError, TypeError): logging.debug('Invalid value for filesize property: %s', properties['filesize']) if 'creation_time' in properties: try: document.add_value( _VALUE_CREATION_TIME, xapian.sortable_serialise( float(properties['creation_time']))) except (ValueError, TypeError): logging.debug('Invalid value for creation_time property: %s', properties['creation_time']) self.set_document(document) properties = dict(properties) self._index_known(document, properties) self._index_unknown(document, properties) def _index_known(self, document, properties): for name, prefix in _QUERY_TERM_MAP.items(): if (name not in properties): continue self._index_property(document, name, properties.pop(name), prefix) def _index_unknown(self, document, properties): for name, value in properties.items(): self._index_property(document, name, value) def _index_property(self, doc, name, value, prefix=''): if name in _PROPERTIES_NOT_TO_INDEX or not value: return if isinstance(value, unicode): value = value.encode('utf-8') elif not isinstance(value, basestring): value = str(value) # We need to add the full value (i.e. not split into words) so # we can enumerate unique values. It also simplifies setting up # dictionary-based queries. if prefix: doc.add_term(_PREFIX_FULL_VALUE + prefix + value) self.index_text(value, 1, prefix or _PREFIX_NONE) self.increase_termpos() class QueryParser (xapian.QueryParser): """QueryParser that understands dictionaries and Xapian query strings. The dictionary contains metadata names as keys and either basic types (exact match), 2-tuples (range, only valid for value-stored metadata) or a list (multiple exact matches joined with OR) as values. An empty dictionary matches everything. Queries from different keys (i.e. different metadata names) are joined with AND. """ def __init__(self): xapian.QueryParser.__init__(self) for name, prefix in _QUERY_TERM_MAP.items(): self.add_prefix(name, prefix) self.add_prefix('', prefix) self.add_prefix('', _PREFIX_NONE) def _parse_query_term(self, name, prefix, value): if isinstance(value, list): subqueries = [self._parse_query_term(name, prefix, word) for word in value] return Query(Query.OP_OR, subqueries) elif prefix: return Query(_PREFIX_FULL_VALUE + prefix + str(value)) else: return Query(_PREFIX_NONE + str(value)) def _parse_query_value_range(self, name, info, value): if len(value) != 2: raise TypeError( 'Only tuples of size 2 have a defined meaning. ' 'Did you mean to pass a list instead?') start, end = value return Query(Query.OP_VALUE_RANGE, info['number'], self._convert_value(info, start), self._convert_value(info, end)) def _convert_value(self, info, value): if info['type'] in (float, int, long): return xapian.sortable_serialise(info['type'](value)) return str(info['type'](value)) def _parse_query_value(self, name, info, value): if isinstance(value, list): subqueries = [self._parse_query_value(name, info, word) for word in value] return Query(Query.OP_OR, subqueries) elif isinstance(value, tuple): return self._parse_query_value_range(name, info, value) elif isinstance(value, dict): # compatibility option for timestamp: {'start': 0, 'end': 1} start = value.get('start', 0) end = value.get('end', sys.maxint) return self._parse_query_value_range(name, info, (start, end)) else: return self._parse_query_value_range(name, info, (value, value)) def _parse_query_xapian(self, query_str): try: return xapian.QueryParser.parse_query( self, query_str, QueryParser.FLAG_PHRASE | QueryParser.FLAG_BOOLEAN | QueryParser.FLAG_LOVEHATE | QueryParser.FLAG_WILDCARD, '') except xapian.QueryParserError, exception: logging.warning('Invalid query string: ' + exception.get_msg()) return Query() def parse_query(self, query_dict, query_string): logging.debug('parse_query %r %r', query_dict, query_string) queries = [] query_dict = dict(query_dict) if query_string is not None: queries.append(self._parse_query_xapian(str(query_string))) for name, value in query_dict.items(): if name in _QUERY_TERM_MAP: queries.append(self._parse_query_term(name, _QUERY_TERM_MAP[name], value)) elif name in _QUERY_VALUE_MAP: queries.append(self._parse_query_value(name, _QUERY_VALUE_MAP[name], value)) else: logging.warning('Unknown term: %r=%r', name, value) if not queries: queries.append(Query('')) logging.debug('queries: %r', [str(q) for q in queries]) return Query(Query.OP_AND, queries) class IndexStore(object): """Index metadata and provide rich query facilities on it. """ def __init__(self): self._database = None self._flush_timeout = None self._pending_writes = 0 self._index_updated_path = os.path.join( layoutmanager.get_instance().get_root_path(), 'index_updated') def open_index(self): index_path = layoutmanager.get_instance().get_index_path() self._database = WritableDatabase(index_path, xapian.DB_CREATE_OR_OPEN) def close_index(self): """Close index database if it is open.""" if not self._database: return self._flush(True) self._database = None def remove_index(self): index_path = layoutmanager.get_instance().get_index_path() if not os.path.exists(index_path): return for f in os.listdir(index_path): os.remove(os.path.join(index_path, f)) def contains(self, uid): postings = self._database.postlist(_PREFIX_FULL_VALUE + \ _PREFIX_UID + uid) try: postlist_item = postings.next() except StopIteration: return False return True def store(self, uid, properties): document = Document() document.add_value(_VALUE_UID, uid) term_generator = TermGenerator() term_generator.index_document(document, properties) if not self.contains(uid): self._database.add_document(document) else: self._database.replace_document(_PREFIX_FULL_VALUE + \ _PREFIX_UID + uid, document) self._flush() def find(self, query): offset = query.pop('offset', 0) limit = query.pop('limit', MAX_QUERY_LIMIT) order_by = query.pop('order_by', []) query_string = query.pop('query', None) query_parser = QueryParser() query_parser.set_database(self._database) enquire = Enquire(self._database) enquire.set_query(query_parser.parse_query(query, query_string)) # This will assure that the results count is exact. check_at_least = offset + limit + 1 if not order_by: order_by = '+timestamp' else: order_by = order_by[0] if order_by == '+timestamp': enquire.set_sort_by_value(_VALUE_TIMESTAMP, True) elif order_by == '-timestamp': enquire.set_sort_by_value(_VALUE_TIMESTAMP, False) elif order_by == '+title': enquire.set_sort_by_value(_VALUE_TITLE, True) elif order_by == '-title': enquire.set_sort_by_value(_VALUE_TITLE, False) elif order_by == '+filesize': enquire.set_sort_by_value(_VALUE_FILESIZE, True) elif order_by == '-filesize': enquire.set_sort_by_value(_VALUE_FILESIZE, False) elif order_by == '+creation_time': enquire.set_sort_by_value(_VALUE_CREATION_TIME, True) elif order_by == '-creation_time': enquire.set_sort_by_value(_VALUE_CREATION_TIME, False) else: logging.warning('Unsupported property for sorting: %s', order_by) query_result = enquire.get_mset(offset, limit, check_at_least) total_count = query_result.get_matches_estimated() uids = [] for hit in query_result: uids.append(hit.document.get_value(_VALUE_UID)) return (uids, total_count) def delete(self, uid): self._database.delete_document(_PREFIX_FULL_VALUE + _PREFIX_UID + uid) self._flush() def get_activities(self): activities = [] prefix = _PREFIX_FULL_VALUE + _PREFIX_ACTIVITY for term in self._database.allterms(prefix): activities.append(term.term[len(prefix):]) return activities def flush(self): self._flush(True) def get_index_updated(self): return os.path.exists(self._index_updated_path) index_updated = property(get_index_updated) def _set_index_updated(self, index_updated): if index_updated != self.index_updated: if index_updated: index_updated_file = open(self._index_updated_path, 'w') # index_updated = True will happen every # indexstore._FLUSH_TIMEOUT seconds, so it is ok to fsync os.fsync(index_updated_file.fileno()) index_updated_file.close() else: os.remove(self._index_updated_path) def _flush_timeout_cb(self): self._flush(True) return False def _flush(self, force=False): """Called after any database mutation""" logging.debug('IndexStore.flush: force=%r _pending_writes=%r', force, self._pending_writes) self._set_index_updated(False) if self._flush_timeout is not None: gobject.source_remove(self._flush_timeout) self._flush_timeout = None self._pending_writes += 1 if force or self._pending_writes > _FLUSH_THRESHOLD: self._database.flush() self._pending_writes = 0 self._set_index_updated(True) else: self._flush_timeout = gobject.timeout_add_seconds(_FLUSH_TIMEOUT, self._flush_timeout_cb)