catapult/tracing/bin/why_imported

#!/usr/bin/env python
# Copyright 2015 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.

"""Produces a dot file showing dependency relationships between modules.

The dot file contains a text-based representation of a directed graph that
explains why given module names were included in a trace_viewer config.

Example usage:
$ ./why_imported tracing.ui.analysis.analysis_view > ~/analysis_view.dot

This can then be converted to a graphical representation with the dot tool:
$ dot -Grankdir=LR -Tpng ~/analysis_view.dot -o ~/analysis_view.png
"""

import os
import sys
import argparse


def Main():
  project = tracing_project.TracingProject()

  parser = argparse.ArgumentParser(
      usage='%(prog)s <options> moduleNames', epilog=__doc__)
  parser.add_argument('--config', choices=project.GetConfigNames())
  parser.add_argument('module_names', nargs='+')
  args = parser.parse_args()

  if args.config:
    names = [project.GetModuleNameForConfigName(options.config)]
    vulcanizer = project.CreateVulcanizer()
    load_sequence = vulcanizer.CalcLoadSequenceForModuleNames(names)
  else:
    parser.error('No config specified.')
  print vulcanizer.GetDominatorGraphForModulesNamed(
      args.module_names, load_sequence)


if __name__ == '__main__':
  tracing_path = os.path.abspath(os.path.join(
    os.path.dirname(os.path.realpath(__file__)), '..'))
  sys.path.append(tracing_path)
  import tracing_project
  tracing_project.UpdateSysPathIfNeeded()
  sys.exit(Main())