pathaddition.relative

+ 1 #============================================================================ + 2 #Name : relative.py + 3 #Part of : Helium + 4 + 5 #Copyright (c) 2009 Nokia Corporation and/or its subsidiary(-ies). + 6 #All rights reserved. + 7 #This component and the accompanying materials are made available + 8 #under the terms of the License "Eclipse Public License v1.0" + 9 #which accompanies this distribution, and is available + 10 #at the URL "http://www.eclipse.org/legal/epl-v10.html". + 11 # + 12 #Initial Contributors: + 13 #Nokia Corporation - initial contribution. + 14 # + 15 #Contributors: + 16 # + 17 #Description: + 18 #=============================================================================== + 19 + 20 """ + 21 Additional path functionnality. + 22 abs2rel + 23 rel2abs + 24 """ + 25 import os + 26 import os.path + 27 import re + 28 + 29 # matches http:// and ftp:// and mailto:// + 30 protocolPattern = re.compile(r'^\w+://') + 31 +

32 -def isabs(string): +

33 """ + 34 + 35 @return true if string is an absolute path or protocoladdress + 36 for addresses beginning in http:// or ftp:// or ldap:// - + 37 they are considered "absolute" paths. + 38 """ + 39 if protocolPattern.match(string): + 40 return True + 41 return os.path.isabs(string) +

42 +

43 -def rel2abs(path, base = None): +

44 """ converts a relative path to an absolute path. + 45 + 46 @param path the path to convert - if already absolute, is returned + 47 without conversion. + 48 @param base - optional. Defaults to the current directory. + 49 The base is intelligently concatenated to the given relative path. + 50 @return the relative path of path from base + 51 """ + 52 if isabs(path): + 53 return path + 54 if base is None: + 55 base = os.curdir + 56 retval = os.path.join(base, path) + 57 return os.path.abspath(retval) +

58 + 59 +

60 -def pathsplit(p, rest=None): +

61 """ Split path to pieces """ + 62 if rest is None: + 63 rest = [] + 64 (h, t) = os.path.split(p) + 65 if len(h) < 1: + 66 return [t]+rest + 67 if len(t) < 1: + 68 return [h]+rest + 69 return pathsplit(h, [t]+rest) +

70 +

71 -def commonpath(l1, l2, common=None): +

72 """ return the common path""" + 73 if common is None: + 74 common = [] + 75 if len(l1) < 1: + 76 return (common, l1, l2) + 77 if len(l2) < 1: + 78 return (common, l1, l2) + 79 if l1[0] != l2[0]: + 80 return (common, l1, l2) + 81 return commonpath(l1[1:], l2[1:], common+[l1[0]]) +

82 + 83 +

84 -def relpath(p1, p2): +

85 (common, l1, l2) = commonpath(pathsplit(p1), pathsplit(p2)) + 86 p = [] + 87 if len(l1) > 0: + 88 p = [ '../' * len(l1) ] + 89 p = p + l2 + 90 if len(p) is 0: + 91 return "." + 92 return os.path.join( *p ) +

93 + 94 +

95 -def abs2rel(path, base = None): +

96 """ @return a relative path from base to path. + 97 + 98 base can be absolute, or relative to curdir, or defaults + 99 to curdir. +100 """ +101 if protocolPattern.match(path): +102 return path +103 if base is None: +104 base = os.curdir +105 base = rel2abs(base) +106 path = rel2abs(path) # redundant - should already be absolute +107 return relpath(base, path) +

108 +109 +

110 -def commonprefix(paths): +

111 """ +112 Returns the common prefix base on the path components. +113 """ +114 if len(paths) == 0: +115 return '' +116 if len(paths) == 1: +117 return paths[0] +118 +119 def _commonprefix_internal(p1, p2): +120 c = commonpath(pathsplit(p1), pathsplit(p2))[0] +121 if len(c) == 0: +122 return '' +123 return os.path.join(*c) +

124 common = _commonprefix_internal(paths[0], paths[1]) +125 for p in paths[2:]: +126 common = _commonprefix_internal(common, p) +127 return common +128 +

Source Code for Module pathaddition.relative