tools/gyp-explain.py

   1 #!/usr/bin/env python
   2 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
   3 # Use of this source code is governed by a BSD-style license that can be
   4 # found in the LICENSE file.
   5
   6 """Prints paths between gyp targets.
   7 """
   8
   9 import json
  10 import os
  11 import sys
  12 import time
  13
  14 from collections import deque
  15
  16 def usage():
  17   print """\
  18 Usage:
  19   tools/gyp-explain.py [--dot] chrome_dll# gtest#
  20 """
  21
  22
  23 def GetPath(graph, fro, to):
  24   """Given a graph in (node -> list of successor nodes) dictionary format,
  25   yields all paths from |fro| to |to|, starting with the shortest."""
  26   # Storing full paths in the queue is a bit wasteful, but good enough for this.
  27   q = deque([(fro, [])])
  28   while q:
  29     t, path = q.popleft()
  30     if t == to:
  31       yield path + [t]
  32     for d in graph[t]:
  33       q.append((d, path + [t]))
  34
  35
  36 def MatchNode(graph, substring):
  37   """Given a dictionary, returns the key that matches |substring| best. Exits
  38   if there's not one single best match."""
  39   candidates = []
  40   for target in graph:
  41     if substring in target:
  42       candidates.append(target)
  43
  44   if not candidates:
  45     print 'No targets match "%s"' % substring
  46     sys.exit(1)
  47   if len(candidates) > 1:
  48     print 'More than one target matches "%s": %s' % (
  49         substring, ' '.join(candidates))
  50     sys.exit(1)
  51   return candidates[0]
  52
  53
  54 def EscapeForDot(string):
  55   suffix = '#target'
  56   if string.endswith(suffix):
  57     string = string[:-len(suffix)]
  58   string = string.replace('\\', '\\\\')
  59   return '"' + string + '"'
  60
  61
  62 def GenerateDot(fro, to, paths):
  63   """Generates an input file for graphviz's dot program."""
  64   prefixes = [os.path.commonprefix(path) for path in paths]
  65   prefix = os.path.commonprefix(prefixes)
  66   print '// Build with "dot -Tpng -ooutput.png this_file.dot"'
  67   # "strict" collapses common paths.
  68   print 'strict digraph {'
  69   for path in paths:
  70     print (' -> '.join(EscapeForDot(item[len(prefix):]) for item in path)), ';'
  71   print '}'
  72
  73
  74 def Main(argv):
  75   # Check that dump.json exists and that it's not too old.
  76   dump_json_dirty = False
  77   try:
  78     st = os.stat('dump.json')
  79     file_age_s = time.time() - st.st_mtime
  80     if file_age_s > 2 * 60 * 60:
  81       print 'dump.json is more than 2 hours old.'
  82       dump_json_dirty = True
  83   except OSError:
  84     print 'dump.json not found.'
  85     dump_json_dirty = True
  86
  87   if dump_json_dirty:
  88     print 'Run'
  89     print '    GYP_GENERATORS=dump_dependency_json build/gyp_chromium'
  90     print 'first, then try again.'
  91     sys.exit(1)
  92
  93   g = json.load(open('dump.json'))
  94
  95   if len(argv) not in (3, 4):
  96     usage()
  97     sys.exit(1)
  98
  99   generate_dot = argv[1] == '--dot'
 100   if generate_dot:
 101     argv.pop(1)
 102
 103   fro = MatchNode(g, argv[1])
 104   to = MatchNode(g, argv[2])
 105
 106   paths = list(GetPath(g, fro, to))
 107   if len(paths) > 0:
 108     if generate_dot:
 109       GenerateDot(fro, to, paths)
 110     else:
 111       print 'These paths lead from %s to %s:' % (fro, to)
 112       for path in paths:
 113         print ' -> '.join(path)
 114   else:
 115     print 'No paths found from %s to %s.' % (fro, to)
 116
 117
 118 if __name__ == '__main__':
 119   Main(sys.argv)