1 # Copyright 2016 The Chromium OS Authors. All rights reserved. 2 # Use of this source code is governed by a BSD-style license that can be 3 # found in the LICENSE file. 4 5 """Feedback query delegate interfaces and implementation registry.""" 6 7 import multiprocessing 8 9 import common 10 from autotest_lib.client.common_lib.feedback import client 11 12 13 # Mapping of query identifiers to delegate classes. 14 _query_delegate_registry = {} 15 16 17 class _QueryDelegate(object): 18 """A base class for query delegates.""" 19 20 _query_count = multiprocessing.Value('d', 0) 21 22 def __init__(self, test, dut, multiplexer, atomic=True): 23 """Constructs the delegate. 24 25 @param test: The name of the test. 26 @param dut: The name of the DUT. 27 @param multiplexer: Feedback request multiplexer object. 28 @param atomic: Whether this is an atomic query. 29 """ 30 super(_QueryDelegate, self).__init__() 31 self.test = test 32 self.dut = dut 33 self._multiplexer = multiplexer 34 self._atomic = atomic 35 36 # Assign a unique query number. 37 with self._query_count.get_lock(): 38 self._query_num = self._query_count.value 39 self._query_count.value += 1 40 41 42 def _process_request(self, req): 43 """Submits a given request to the multiplexer for processing.""" 44 return self._multiplexer.process_request(req, self._query_num, 45 self._atomic) 46 47 48 def prepare(self, **kwargs): 49 """Delegate for a query's prepare() method.""" 50 return self._prepare_impl(**kwargs) 51 52 53 def _prepare_impl(self, **kwargs): 54 """Concrete implementation of the query's prepare() call.""" 55 raise NotImplementedError 56 57 58 def validate(self, **kwargs): 59 """Delegate for a query's validate() method. 60 61 This clears the atomic sequence with the multiplexer to make sure it 62 isn't blocked waiting for more requests from this query. 63 """ 64 try: 65 return self._validate_impl(**kwargs) 66 finally: 67 if self._atomic: 68 self._multiplexer.end_atomic_seq(self._query_num) 69 70 71 def _validate_impl(self, **kwargs): 72 """Concrete implementation of the query's validate() call.""" 73 raise NotImplementedError 74 75 76 class OutputQueryDelegate(_QueryDelegate): 77 """A base class for output query delegates.""" 78 79 80 class InputQueryDelegate(_QueryDelegate): 81 """A base class for input query delegates.""" 82 83 def emit(self): 84 """Delegate for an input query's emit() method.""" 85 return self._emit_impl() 86 87 88 def _emit_impl(self): 89 """Concrete implementation of the query's emit() call.""" 90 raise NotImplementedError 91 92 93 def register_delegate_cls(query_id, delegate_cls): 94 """Registers a delegate class with a given query identifier. 95 96 @param query_id: Query identifier constant. 97 @param delegate_cls: The class implementing a delegate for this query. 98 """ 99 _query_delegate_registry[query_id] = delegate_cls 100 101 102 def get_delegate_cls(query_id): 103 """Returns a query delegate class for a given query type. 104 105 @param query_id: A query type identifier. 106 107 @return A query delegate class. 108 109 @raise ValueError: Unknown query type. 110 @raise NotImplementedError: Query type not supported. 111 """ 112 if query_id not in client.ALL_QUERIES: 113 raise ValueError 114 if query_id not in _query_delegate_registry: 115 raise NotImplementedError 116 return _query_delegate_registry[query_id] 117
