1# Copyright 2014 the V8 project authors. All rights reserved.
2# Use of this source code is governed by a BSD-style license that can be
3# found in the LICENSE file.
4"""Small utility function to find depot_tools and add it to the python path.
5"""
6
7import os
8import sys
9
10
11def directory_really_is_depot_tools(directory):
12  return os.path.isfile(os.path.join(directory, 'gclient.py'))
13
14
15def add_depot_tools_to_path():
16  """Search for depot_tools and add it to sys.path."""
17  # First look if depot_tools is already in PYTHONPATH.
18  for i in sys.path:
19    if i.rstrip(os.sep).endswith('depot_tools'):
20      if directory_really_is_depot_tools(i):
21        return i
22
23  # Then look if depot_tools is in PATH, common case.
24  for i in os.environ['PATH'].split(os.pathsep):
25    if i.rstrip(os.sep).endswith('depot_tools'):
26      if directory_really_is_depot_tools(i):
27        sys.path.insert(0, i.rstrip(os.sep))
28        return i
29  # Rare case, it's not even in PATH, look upward up to root.
30  root_dir = os.path.dirname(os.path.abspath(__file__))
31  previous_dir = os.path.abspath(__file__)
32  while root_dir and root_dir != previous_dir:
33    if directory_really_is_depot_tools(os.path.join(root_dir, 'depot_tools')):
34      i = os.path.join(root_dir, 'depot_tools')
35      sys.path.insert(0, i)
36      return i
37    previous_dir = root_dir
38    root_dir = os.path.dirname(root_dir)
39  print >> sys.stderr, 'Failed to find depot_tools'
40  return None
41