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      1 # Copyright 2013 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 """A Telemetry page_action that performs the "play" action on media elements.
      6 
      7 Media elements can be specified by a selector argument. If no selector is
      8 defined then then the action attempts to play the first video element or audio
      9 element on the page. A selector can also be 'all' to play all media elements.
     10 
     11 Other arguments to use are: playing_event_timeout_in_seconds and
     12 ended_event_timeout_in_seconds, which forces the action to wait until
     13 playing and ended events get fired respectively.
     14 """
     15 
     16 from telemetry.core import exceptions
     17 from telemetry.page.actions import media_action
     18 from telemetry.page.actions import page_action
     19 
     20 
     21 class PlayAction(media_action.MediaAction):
     22   def __init__(self, selector=None,
     23                playing_event_timeout_in_seconds=0,
     24                ended_event_timeout_in_seconds=0):
     25     super(PlayAction, self).__init__()
     26     self._selector = selector if selector else ''
     27     self._playing_event_timeout_in_seconds = playing_event_timeout_in_seconds
     28     self._ended_event_timeout_in_seconds = ended_event_timeout_in_seconds
     29 
     30   def WillRunAction(self, tab):
     31     """Load the media metrics JS code prior to running the action."""
     32     super(PlayAction, self).WillRunAction(tab)
     33     self.LoadJS(tab, 'play.js')
     34 
     35   def RunAction(self, tab):
     36     try:
     37       tab.ExecuteJavaScript('window.__playMedia("%s");' % self._selector)
     38       # Check if we need to wait for 'playing' event to fire.
     39       if self._playing_event_timeout_in_seconds > 0:
     40         self.WaitForEvent(tab, self._selector, 'playing',
     41                           self._playing_event_timeout_in_seconds)
     42       # Check if we need to wait for 'ended' event to fire.
     43       if self._ended_event_timeout_in_seconds > 0:
     44         self.WaitForEvent(tab, self._selector, 'ended',
     45                           self._ended_event_timeout_in_seconds)
     46     except exceptions.EvaluateException:
     47       raise page_action.PageActionFailed('Cannot play media element(s) with '
     48                                          'selector = %s.' % self._selector)
     49