def WriteGraph(edges):

  # Bucket targets by file.
  files = collections.defaultdict(list)
  for src, dst in edges.items():
    build_file, target_name, toolset = ParseTarget(src)
    files[build_file].append(src)

  print 'digraph D {'
  print '  fontsize=8'  # Used by subgraphs.
  print '  node [fontsize=8]'

  # Output nodes by file.  We must first write out each node within
  # its file grouping before writing out any edges that may refer
  # to those nodes.
  for filename, targets in files.items():
    if len(targets) == 1:
      # If there's only one node for this file, simplify
      # the display by making it a box without an internal node.
      target = targets[0]
      build_file, target_name, toolset = ParseTarget(target)
      print '  "%s" [shape=box, label="%s\\n%s"]' % (target, filename,
                                                     target_name)
    else:
      # Group multiple nodes together in a subgraph.
      print '  subgraph "cluster_%s" {' % filename
      print '    label = "%s"' % filename
      for target in targets:
        build_file, target_name, toolset = ParseTarget(target)
        print '    "%s" [label="%s"]' % (target, target_name)
      print '  }'

  # Now that we've placed all the nodes within subgraphs, output all
  # the edges between nodes.
  for src, dsts in edges.items():
    for dst in dsts:
      print '  "%s" -> "%s"' % (src, dst)

  print '}'
Print a graphviz graph to stdout.
dataset/ETHPy150Open adblockplus/gyp/tools/graphviz.py/WriteGraph