71 lines
2.9 KiB
Python
71 lines
2.9 KiB
Python
# Copyright 2013 OpenStack Foundation
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# Copyright 2013 IBM Corp.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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class Hints(object):
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"""Encapsulate driver hints for listing entities.
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Hints are modifiers that affect the return of entities from a
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list_<entities> operation. They are typically passed to a driver to give
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direction as to what filtering, pagination or list limiting actions are
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being requested.
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It is optional for a driver to action some or all of the list hints,
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but any filters that it does satisfy must be marked as such by calling
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removing the filter from the list.
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A Hint object contains filters, which is a list of dicts that can be
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accessed publicly. Also it contains a dict called limit, which will
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indicate the amount of data we want to limit our listing to.
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If the filter is discovered to never match, then `cannot_match` can be set
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to indicate that there will not be any matches and the backend work can be
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short-circuited.
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Each filter term consists of:
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* ``name``: the name of the attribute being matched
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* ``value``: the value against which it is being matched
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* ``comparator``: the operation, which can be one of ``equals``,
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``startswith`` or ``endswith``
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* ``case_sensitive``: whether any comparison should take account of
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case
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* ``type``: will always be 'filter'
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"""
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def __init__(self):
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self.limit = None
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self.filters = list()
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self.cannot_match = False
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def add_filter(self, name, value, comparator='equals',
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case_sensitive=False):
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"""Adds a filter to the filters list, which is publicly accessible."""
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self.filters.append({'name': name, 'value': value,
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'comparator': comparator,
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'case_sensitive': case_sensitive,
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'type': 'filter'})
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def get_exact_filter_by_name(self, name):
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"""Return a filter key and value if exact filter exists for name."""
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for entry in self.filters:
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if (entry['type'] == 'filter' and entry['name'] == name and
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entry['comparator'] == 'equals'):
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return entry
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def set_limit(self, limit, truncated=False):
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"""Set a limit to indicate the list should be truncated."""
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self.limit = {'limit': limit, 'type': 'limit', 'truncated': truncated}
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