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 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 Main(argv):
  55   if sys.platform in ['win32', 'cygwin']:
  56     print 'The dump_dependency_json gyp generator required for gyp-explain.py'
  57     print 'does not support Windows.'
  58     sys.exit(1)
  59
  60   # Check that dump.json exists and that it's not too old.
  61   dump_json_dirty = False
  62   try:
  63     st = os.stat('dump.json')
  64     file_age_s = time.time() - st.st_mtime
  65     if file_age_s > 2 * 60 * 60:
  66       print 'dump.json is more than 2 hours old.'
  67       dump_json_dirty = True
  68   except OSError:
  69     print 'dump.json not found.'
  70     dump_json_dirty = True
  71
  72   if dump_json_dirty:
  73     print 'Run'
  74     print '    GYP_GENERATORS=dump_dependency_json build/gyp_chromium'
  75     print 'first, then try again.'
  76     sys.exit(1)
  77
  78   g = json.load(open('dump.json'))
  79
  80   if len(argv) != 3:
  81     usage()
  82     sys.exit(1)
  83
  84   fro = MatchNode(g, argv[1])
  85   to = MatchNode(g, argv[2])
  86
  87   paths = list(GetPath(g, fro, to))
  88   if len(paths) > 0:
  89     print 'These paths lead from %s to %s:' % (fro, to)
  90     for path in paths:
  91       print ' -> '.join(path)
  92   else:
  93     print 'No paths found from %s to %s.' % (fro, to)
  94
  95
  96 if __name__ == '__main__':
  97   Main(sys.argv)