# Copyright 2016 The Chromium OS Authors. All rights reserved.
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# Use of this source code is governed by a BSD-style license that can be
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# found in the LICENSE file.
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"""Feedback query delegate interfaces and implementation registry."""
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import multiprocessing
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import common
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from autotest_lib.client.common_lib.feedback import client
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# Mapping of query identifiers to delegate classes.
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_query_delegate_registry = {}
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class _QueryDelegate(object):
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"""A base class for query delegates."""
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_query_count = multiprocessing.Value('d', 0)
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def __init__(self, test, dut, multiplexer, atomic=True):
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"""Constructs the delegate.
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@param test: The name of the test.
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@param dut: The name of the DUT.
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@param multiplexer: Feedback request multiplexer object.
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@param atomic: Whether this is an atomic query.
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"""
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super(_QueryDelegate, self).__init__()
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self.test = test
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self.dut = dut
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self._multiplexer = multiplexer
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self._atomic = atomic
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# Assign a unique query number.
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with self._query_count.get_lock():
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self._query_num = self._query_count.value
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self._query_count.value += 1
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def _process_request(self, req):
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"""Submits a given request to the multiplexer for processing."""
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return self._multiplexer.process_request(req, self._query_num,
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self._atomic)
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def prepare(self, **kwargs):
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"""Delegate for a query's prepare() method."""
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return self._prepare_impl(**kwargs)
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def _prepare_impl(self, **kwargs):
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"""Concrete implementation of the query's prepare() call."""
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raise NotImplementedError
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def validate(self, **kwargs):
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"""Delegate for a query's validate() method.
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This clears the atomic sequence with the multiplexer to make sure it
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isn't blocked waiting for more requests from this query.
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"""
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try:
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return self._validate_impl(**kwargs)
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finally:
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if self._atomic:
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self._multiplexer.end_atomic_seq(self._query_num)
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def _validate_impl(self, **kwargs):
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"""Concrete implementation of the query's validate() call."""
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raise NotImplementedError
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class OutputQueryDelegate(_QueryDelegate):
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"""A base class for output query delegates."""
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class InputQueryDelegate(_QueryDelegate):
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"""A base class for input query delegates."""
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def emit(self):
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"""Delegate for an input query's emit() method."""
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return self._emit_impl()
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def _emit_impl(self):
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"""Concrete implementation of the query's emit() call."""
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raise NotImplementedError
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def register_delegate_cls(query_id, delegate_cls):
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"""Registers a delegate class with a given query identifier.
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@param query_id: Query identifier constant.
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@param delegate_cls: The class implementing a delegate for this query.
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"""
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_query_delegate_registry[query_id] = delegate_cls
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def get_delegate_cls(query_id):
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"""Returns a query delegate class for a given query type.
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@param query_id: A query type identifier.
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@return A query delegate class.
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@raise ValueError: Unknown query type.
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@raise NotImplementedError: Query type not supported.
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"""
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if query_id not in client.ALL_QUERIES:
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raise ValueError
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if query_id not in _query_delegate_registry:
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raise NotImplementedError
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return _query_delegate_registry[query_id]
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