tools/profile_chrome/profiler.py

# Copyright 2014 The Chromium Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

import os

from profile_chrome import trace_packager
from profile_chrome import ui

from pylib import constants


def _StartTracing(controllers, interval):
  for controller in controllers:
    controller.StartTracing(interval)


def _StopTracing(controllers):
  for controller in controllers:
    controller.StopTracing()


def _PullTraces(controllers, output, compress, write_json):
  ui.PrintMessage('Downloading...', eol='')
  trace_files = [controller.PullTrace() for controller in controllers]
  trace_files = [trace for trace in trace_files if trace]
  if not trace_files:
    ui.PrintMessage('No results')
    return []
  result = trace_packager.PackageTraces(trace_files,
                                        output=output,
                                        compress=compress,
                                        write_json=write_json)
  ui.PrintMessage('done')
  ui.PrintMessage('Trace written to file://%s' % os.path.abspath(result))
  return result


def GetSupportedBrowsers():
  """Returns the package names of all supported browsers."""
  # Add aliases for backwards compatibility.
  supported_browsers = {
    'stable': constants.PACKAGE_INFO['chrome_stable'],
    'beta': constants.PACKAGE_INFO['chrome_beta'],
    'dev': constants.PACKAGE_INFO['chrome_dev'],
    'build': constants.PACKAGE_INFO['chrome'],
  }
  supported_browsers.update(constants.PACKAGE_INFO)
  unsupported_browsers = ['content_browsertests', 'gtest', 'legacy_browser']
  for browser in unsupported_browsers:
    del supported_browsers[browser]
  return supported_browsers


def CaptureProfile(controllers, interval, output=None, compress=False,
                   write_json=False):
  """Records a profiling trace saves the result to a file.

  Args:
    controllers: List of tracing controllers.
    interval: Time interval to capture in seconds. An interval of None (or 0)
        continues tracing until stopped by the user.
    output: Output file name or None to use an automatically generated name.
    compress: If True, the result will be compressed either with gzip or zip
        depending on the number of captured subtraces.
    write_json: If True, prefer JSON output over HTML.

  Returns:
    Path to saved profile.
  """
  trace_type = ' + '.join(map(str, controllers))
  try:
    _StartTracing(controllers, interval)
    if interval:
      ui.PrintMessage('Capturing %d-second %s. Press Enter to stop early...' % \
          (interval, trace_type), eol='')
      ui.WaitForEnter(interval)
    else:
      ui.PrintMessage('Capturing %s. Press Enter to stop...' % \
          trace_type, eol='')
      raw_input()
  finally:
    _StopTracing(controllers)
  if interval:
    ui.PrintMessage('done')

  return _PullTraces(controllers, output, compress, write_json)