1import os
2import subprocess
3import re
4import sys
5
6def which(cmd):
7  for p in os.environ["PATH"].split(os.pathsep):
8    clang_path = os.path.join(p, cmd)
9    if os.path.exists(clang_path):
10      return clang_path
11  return None
12
13CLANG_VERSION_REGEX=".*version\s*([0-9]*\.[0-9]*)\.*"
14clang_path = which("clang++")
15clang_version_major = 0
16clang_version_minor = 0
17
18if clang_path:
19  clang_version_out = subprocess.Popen([clang_path, "--version"],
20    stdout=subprocess.PIPE).communicate()[0]
21  clang_version_match = re.search(CLANG_VERSION_REGEX, clang_version_out)
22  clang_version_str = clang_version_match.group(1)
23  clang_version_array = clang_version_str.split('.')
24  clang_version_major = int(clang_version_array[0])
25  clang_version_minor = int(clang_version_array[1])
26
27if clang_version_major >= 3 and clang_version_minor >= 5:
28  print ""
29else:
30  # Loop in support clang version only
31  clang_version_major = 3
32  clang_version_minor = 9
33  while clang_version_major >= 3 and clang_version_minor >= 5:
34    clang_version_str = "%d.%d" % (clang_version_major, clang_version_minor)
35    clang_path = which("clang++-" + clang_version_str)
36    if clang_path:
37      print clang_version_str
38      sys.exit(0)
39    clang_version_minor -= 1
40    if clang_version_minor < 0:
41      clang_version_minor = 9
42      clang_version_major -= 1
43  print "None"
44