1 # Copyright (c) 2011 The Chromium 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 5 """Some utility methods for getting and manipulating paths.""" 6 7 # TODO(pamg): Have the buildbot use these, too. 8 9 10 import errno 11 import os 12 import sys 13 14 class PathNotFound(Exception): pass 15 16 def ScriptDir(): 17 """Get the full path to the directory containing the current script.""" 18 script_filename = os.path.abspath(sys.argv[0]) 19 return os.path.dirname(script_filename) 20 21 def FindAncestor(start_dir, ancestor): 22 """Finds an ancestor dir in a path. 23 24 For example, FindAncestor('c:\foo\bar\baz', 'bar') would return 25 'c:\foo\bar'. Unlike FindUpward*, this only looks at direct path ancestors. 26 """ 27 start_dir = os.path.abspath(start_dir) 28 path = start_dir 29 while True: 30 (parent, tail) = os.path.split(path) 31 if tail == ancestor: 32 return path 33 if not tail: 34 break 35 path = parent 36 raise PathNotFound("Unable to find ancestor %s in %s" % (ancestor, start_dir)) 37 38 def FindUpwardParent(start_dir, *desired_list): 39 """Finds the desired object's parent, searching upward from the start_dir. 40 41 Searches start_dir and all its parents looking for the desired directory 42 or file, which may be given in one or more path components. Returns the 43 first directory in which the top desired path component was found, or raises 44 PathNotFound if it wasn't. 45 """ 46 desired_path = os.path.join(*desired_list) 47 last_dir = '' 48 cur_dir = start_dir 49 found_path = os.path.join(cur_dir, desired_path) 50 while not os.path.exists(found_path): 51 last_dir = cur_dir 52 cur_dir = os.path.dirname(cur_dir) 53 if last_dir == cur_dir: 54 raise PathNotFound('Unable to find %s above %s' % 55 (desired_path, start_dir)) 56 found_path = os.path.join(cur_dir, desired_path) 57 # Strip the entire original desired path from the end of the one found 58 # and remove a trailing path separator, if present. 59 found_path = found_path[:len(found_path) - len(desired_path)] 60 if found_path.endswith(os.sep): 61 found_path = found_path[:len(found_path) - 1] 62 return found_path 63 64 65 def FindUpward(start_dir, *desired_list): 66 """Returns a path to the desired directory or file, searching upward. 67 68 Searches start_dir and all its parents looking for the desired directory 69 or file, which may be given in one or more path components. Returns the full 70 path to the desired object, or raises PathNotFound if it wasn't found. 71 """ 72 parent = FindUpwardParent(start_dir, *desired_list) 73 return os.path.join(parent, *desired_list) 74 75 76 def MaybeMakeDirectory(*path): 77 """Creates an entire path, if it doesn't already exist.""" 78 file_path = os.path.join(*path) 79 try: 80 os.makedirs(file_path) 81 except OSError, e: 82 # errno.EEXIST is "File exists". If we see another error, re-raise. 83 if e.errno != errno.EEXIST: 84 raise 85
