sdk/platform-tools/systrace/catapult/telemetry/telemetry/internal/backends/chrome_inspector/inspector_memory.py

   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 import json
   5
   6 from telemetry.core import exceptions
   7
   8
   9 class InspectorMemoryException(exceptions.Error):
  10   pass
  11
  12
  13 class InspectorMemory(object):
  14   """Communicates with the remote inspector's Memory domain."""
  15
  16   def __init__(self, inspector_websocket):
  17     self._inspector_websocket = inspector_websocket
  18     self._inspector_websocket.RegisterDomain('Memory', self._OnNotification)
  19
  20   def _OnNotification(self, msg):
  21     pass
  22
  23   def GetDOMCounters(self, timeout):
  24     """Retrieves DOM element counts.
  25
  26     Args:
  27       timeout: The number of seconds to wait for the inspector backend to
  28           service the request before timing out.
  29
  30     Returns:
  31       A dictionary containing the counts associated with "nodes", "documents",
  32       and "jsEventListeners".
  33     Raises:
  34       InspectorMemoryException
  35       websocket.WebSocketException
  36       socket.error
  37       exceptions.WebSocketDisconnected
  38     """
  39     res = self._inspector_websocket.SyncRequest({
  40       'method': 'Memory.getDOMCounters'
  41     }, timeout)
  42     if ('result' not in res or
  43         'nodes' not in res['result'] or
  44         'documents' not in res['result'] or
  45         'jsEventListeners' not in res['result']):
  46       raise InspectorMemoryException(
  47           'Inspector returned unexpected result for Memory.getDOMCounters:\n' +
  48           json.dumps(res, indent=2))
  49     return {
  50         'nodes': res['result']['nodes'],
  51         'documents': res['result']['documents'],
  52         'jsEventListeners': res['result']['jsEventListeners']
  53     }