1 # Copyright (c) 2012 The Chromium 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 """Worker thread base class. 6 7 Worker threads are used to run multiple PyUITests simultaneously. They 8 synchronize calls to the browser.""" 9 10 import itertools 11 import threading 12 import pyauto 13 14 15 # A static lock used to synchronize worker threads access to the browser. 16 __lock = threading.RLock() 17 18 def synchronized(fn): 19 """A decorator to wrap a lock around function calls.""" 20 def syncFun(*args, **kwargs): 21 with __lock: 22 return fn(*args, **kwargs) 23 24 return syncFun 25 26 27 def RunWorkerThreads(pyauto_test, test_worker_class, tasks, num_threads, 28 test_path): 29 """Creates a matrix of tasks and starts test worker threads to run them. 30 31 Args: 32 pyauto_test: Reference to a pyauto.PyUITest instance. 33 test_worker_class: WorkerThread class reference. 34 tasks: Queue of tasks to run by the worker threads. 35 num_threads: Number of threads to run simultaneously. 36 test_path: Path to HTML/JavaScript test code. 37 """ 38 # Convert relative test path into an absolute path. 39 test_url = pyauto_test.GetFileURLForDataPath(test_path) 40 41 # Add shutdown magic to end of queue. 42 for _ in xrange(num_threads): 43 tasks.put(None) 44 45 threads = [] 46 for _ in xrange(num_threads): 47 threads.append(test_worker_class(pyauto_test, tasks, test_url)) 48 49 # Wait for threads to exit, gracefully or otherwise. 50 for thread in threads: 51 thread.join() 52 53 return sum(thread.failures for thread in threads) 54 55 56 class WorkerThread(threading.Thread): 57 """Thread which for each queue task: opens tab, runs task, closes tab.""" 58 59 # Atomic, monotonically increasing task identifier. Used to ID tabs. 60 _task_id = itertools.count() 61 62 def __init__(self, pyauto_test, tasks, url): 63 """Sets up WorkerThread class variables. 64 65 Args: 66 pyauto_test: Reference to a pyauto.PyUITest instance. 67 tasks: Queue containing task tuples used by RunTest(). 68 url: File URL to HTML/JavaScript test code. 69 """ 70 threading.Thread.__init__(self) 71 self.__pyauto = pyauto_test 72 self.__tasks = tasks 73 self.__url = url 74 self.failures = 0 75 self.start() 76 77 def RunTask(self, unique_url, task): 78 """Runs the specific task on the url test page. 79 80 This method should be overridden to start the test on the unique_url page. 81 82 Args: 83 unique_url: A unique identifier of the test page. 84 task: A tuple with information needed to run the test. 85 Returns: 86 True if the task finished as expected. 87 """ 88 raise NotImplementedError('RunTask should be defined in a subclass.') 89 90 def run(self): 91 """For each task in queue: opens new tab, calls RunTask(), then closes tab. 92 93 No exception handling is done to make sure the main thread exits properly 94 during Chrome crashes or other failures. 95 96 For a clean shutdown, put the magic exit value None in the queue. 97 """ 98 while True: 99 task = self.__tasks.get() 100 # Check for magic exit values. 101 if task is None: 102 break 103 # Make the test URL unique so we can figure out our tab index later. 104 unique_url = '%s?%d' % (self.__url, WorkerThread._task_id.next()) 105 self.AppendTab(unique_url) 106 if not self.RunTask(unique_url, task): 107 self.failures += 1 108 self.CloseTabByURL(unique_url) 109 self.__tasks.task_done() 110 111 def __FindTabLocked(self, url): 112 """Returns the tab index for the tab belonging to this url. 113 114 __lock must be owned by caller. 115 """ 116 if url is None: 117 return 0 118 for tab in self.__pyauto.GetBrowserInfo()['windows'][0]['tabs']: 119 if tab['url'] == url: 120 return tab['index'] 121 122 # The following are wrappers to pyauto.PyUITest functions. They are wrapped 123 # with an internal lock to avoid problems when more than one thread edits the 124 # state of the browser. 125 # 126 # We limit access of subclasses to the following functions. If subclasses 127 # access other PyUITest functions, then there is no guarantee of thread 128 # safety. 129 # 130 # For details on the args check pyauto.PyUITest class. 131 @synchronized 132 def AppendTab(self, url): 133 self.__pyauto.AppendTab(pyauto.GURL(url)) 134 135 @synchronized 136 def CallJavascriptFunc(self, fun_name, fun_args=[], url=None): 137 return self.__pyauto.CallJavascriptFunc(fun_name, fun_args, 138 tab_index=self.__FindTabLocked(url)) 139 140 @synchronized 141 def CloseTabByURL(self, url): 142 """Closes the tab with the given url.""" 143 self.__pyauto.CloseTab(tab_index=self.__FindTabLocked(url)) 144 145 @synchronized 146 def GetDOMValue(self, name, url=None): 147 return self.__pyauto.GetDOMValue(name, tab_index=self.__FindTabLocked(url)) 148 149 def WaitUntil(self, *args, **kwargs): 150 """We do not need to lock WaitUntil since it does not call into Chrome. 151 152 Ensure that the function passed in the args is thread safe. 153 """ 154 return self.__pyauto.WaitUntil(*args, **kwargs) 155
