diff options
Diffstat (limited to 'Lib/ntpath.py')
| -rw-r--r-- | Lib/ntpath.py | 412 |
1 files changed, 223 insertions, 189 deletions
diff --git a/Lib/ntpath.py b/Lib/ntpath.py index 224e65e..0d7ef65 100644 --- a/Lib/ntpath.py +++ b/Lib/ntpath.py @@ -1,4 +1,8 @@ -# Module 'ntpath' -- common operations on DOS pathnames +# Module 'ntpath' -- common operations on WinNT/Win95 pathnames +"""Common pathname manipulations, WindowsNT/95 version. +Instead of importing this module +directly, import os and refer to this module as os.path. +""" import os import stat @@ -10,9 +14,11 @@ import string # (this is done by normpath). _normtable = string.maketrans(string.uppercase + "\\/", - string.lowercase + os.sep * 2) + string.lowercase + os.sep * 2) def normcase(s): + """Normalize case of pathname. Makes all characters lowercase and all +slashes into backslashes""" return string.translate(s, _normtable) @@ -23,31 +29,35 @@ def normcase(s): # a slash or backslash. def isabs(s): - s = splitdrive(s)[1] - return s != '' and s[:1] in '/\\' + """Test whether a path is absolute""" + s = splitdrive(s)[1] + return s != '' and s[:1] in '/\\' # Join two (or more) paths. def join(a, *p): - path = a - for b in p: - if isabs(b): - path = b - elif path == '' or path[-1:] in '/\\': - path = path + b - else: - path = path + os.sep + b - return path + """Join two or more pathname components, inserting "\\" as needed""" + path = a + for b in p: + if isabs(b): + path = b + elif path == '' or path[-1:] in '/\\': + path = path + b + else: + path = path + os.sep + b + return path # Split a path in a drive specification (a drive letter followed by a # colon) and the path specification. # It is always true that drivespec + pathspec == p def splitdrive(p): - if p[1:2] == ':': - return p[0:2], p[2:] - return '', p + """Split a pathname into drive and path specifiers. Returns a 2-tuple +"(drive,path)"; either part may be empty""" + if p[1:2] == ':': + return p[0:2], p[2:] + return '', p # Split a path in head (everything up to the last '/') and tail (the @@ -57,25 +67,27 @@ def splitdrive(p): # The resulting head won't end in '/' unless it is the root. def split(p): - d, p = splitdrive(p) - slashes = '' - while p and p[-1:] in '/\\': - slashes = slashes + p[-1] - p = p[:-1] - if p == '': - p = p + slashes - head, tail = '', '' - for c in p: - tail = tail + c - if c in '/\\': - head, tail = head + tail, '' - slashes = '' - while head and head[-1:] in '/\\': - slashes = slashes + head[-1] - head = head[:-1] - if head == '': - head = head + slashes - return d + head, tail + """Split a pathname. Returns tuple "(head, tail)" where "tail" is +everything after the final slash. Either part may be empty""" + d, p = splitdrive(p) + slashes = '' + while p and p[-1:] in '/\\': + slashes = slashes + p[-1] + p = p[:-1] + if p == '': + p = p + slashes + head, tail = '', '' + for c in p: + tail = tail + c + if c in '/\\': + head, tail = head + tail, '' + slashes = '' + while head and head[-1:] in '/\\': + slashes = slashes + head[-1] + head = head[:-1] + if head == '': + head = head + slashes + return d + head, tail # Split a path in root and extension. @@ -84,64 +96,71 @@ def split(p): # It is always true that root + ext == p. def splitext(p): - root, ext = '', '' - for c in p: - if c in ['/','\\']: - root, ext = root + ext + c, '' - elif c == '.': - if ext: - root, ext = root + ext, c - else: - ext = c - elif ext: - ext = ext + c - else: - root = root + c - return root, ext + """Split the extension from a pathname. Extension is everything from the +last dot to the end. Returns "(root, ext)", either part may be empty""" + root, ext = '', '' + for c in p: + if c in ['/','\\']: + root, ext = root + ext + c, '' + elif c == '.': + if ext: + root, ext = root + ext, c + else: + ext = c + elif ext: + ext = ext + c + else: + root = root + c + return root, ext # Return the tail (basename) part of a path. def basename(p): - return split(p)[1] + """Returns the final component of a pathname""" + return split(p)[1] # Return the head (dirname) part of a path. def dirname(p): - return split(p)[0] + """Returns the directory component of a pathname""" + return split(p)[0] # Return the longest prefix of all list elements. def commonprefix(m): - if not m: return '' - prefix = m[0] - for item in m: - for i in range(len(prefix)): - if prefix[:i+1] <> item[:i+1]: - prefix = prefix[:i] - if i == 0: return '' - break - return prefix + "Given a list of pathnames, returns the longest common leading component" + if not m: return '' + prefix = m[0] + for item in m: + for i in range(len(prefix)): + if prefix[:i+1] <> item[:i+1]: + prefix = prefix[:i] + if i == 0: return '' + break + return prefix # Is a path a symbolic link? # This will always return false on systems where posix.lstat doesn't exist. def islink(path): - return 0 + """Test for symbolic link. On WindowsNT/95 always returns false""" + return 0 # Does a path exist? # This is false for dangling symbolic links. def exists(path): - try: - st = os.stat(path) - except os.error: - return 0 - return 1 + """Test whether a path exists""" + try: + st = os.stat(path) + except os.error: + return 0 + return 1 # Is a path a dos directory? @@ -149,11 +168,12 @@ def exists(path): # for the same path. def isdir(path): - try: - st = os.stat(path) - except os.error: - return 0 - return stat.S_ISDIR(st[stat.ST_MODE]) + """Test whether a path is a directory""" + try: + st = os.stat(path) + except os.error: + return 0 + return stat.S_ISDIR(st[stat.ST_MODE]) # Is a path a regular file? @@ -161,19 +181,21 @@ def isdir(path): # for the same path. def isfile(path): - try: - st = os.stat(path) - except os.error: - return 0 - return stat.S_ISREG(st[stat.ST_MODE]) + """Test whether a path is a regular file""" + try: + st = os.stat(path) + except os.error: + return 0 + return stat.S_ISREG(st[stat.ST_MODE]) # Are two filenames really pointing to the same file? def samefile(f1, f2): - s1 = os.stat(f1) - s2 = os.stat(f2) - return samestat(s1, s2) + """Test whether two pathnames reference the same actual file""" + s1 = os.stat(f1) + s2 = os.stat(f2) + return samestat(s1, s2) # Are two open files really referencing the same file? @@ -181,24 +203,28 @@ def samefile(f1, f2): # XXX THIS IS BROKEN UNDER DOS! ST_INO seems to indicate number of reads? def sameopenfile(fp1, fp2): - s1 = os.fstat(fp1.fileno()) - s2 = os.fstat(fp2.fileno()) - return samestat(s1, s2) + """Test whether two open file objects reference the same file (may not +work correctly)""" + s1 = os.fstat(fp1.fileno()) + s2 = os.fstat(fp2.fileno()) + return samestat(s1, s2) # Are two stat buffers (obtained from stat, fstat or lstat) # describing the same file? def samestat(s1, s2): - return s1[stat.ST_INO] == s2[stat.ST_INO] and \ - s1[stat.ST_DEV] == s2[stat.ST_DEV] + """Test whether two stat buffers reference the same file""" + return s1[stat.ST_INO] == s2[stat.ST_INO] and \ + s1[stat.ST_DEV] == s2[stat.ST_DEV] # Is a path a mount point? # XXX This degenerates in: 'is this the root?' on DOS def ismount(path): - return isabs(splitdrive(path)[1]) + """Test whether a path is a mount point""" + return isabs(splitdrive(path)[1]) # Directory tree walk. @@ -210,17 +236,21 @@ def ismount(path): # or to impose a different order of visiting. def walk(top, func, arg): - try: - names = os.listdir(top) - except os.error: - return - func(arg, top, names) - exceptions = ('.', '..') - for name in names: - if name not in exceptions: - name = join(top, name) - if isdir(name): - walk(name, func, arg) + """walk(top,func,args) calls func(arg, d, files) for each directory "d" +in the tree rooted at "top" (including "top" itself). "files" is a list +of all the files and subdirs in directory "d". +""" + try: + names = os.listdir(top) + except os.error: + return + func(arg, top, names) + exceptions = ('.', '..') + for name in names: + if name not in exceptions: + name = join(top, name) + if isdir(name): + walk(name, func, arg) # Expand paths beginning with '~' or '~user'. @@ -233,86 +263,90 @@ def walk(top, func, arg): # variable expansion.) def expanduser(path): - if path[:1] <> '~': - return path - i, n = 1, len(path) - while i < n and path[i] not in '/\\': - i = i+1 - if i == 1: - if os.environ.has_key('HOME'): - userhome = os.environ['HOME'] - elif not os.environ.has_key('HOMEPATH'): - return path - else: - try: - drive=os.environ['HOMEDRIVE'] - except KeyError: - drive = '' - userhome = join(drive, os.environ['HOMEPATH']) - else: - return path - return userhome + path[i:] + """Expand ~ and ~user constructions. If user or $HOME is unknown, +do nothing""" + if path[:1] <> '~': + return path + i, n = 1, len(path) + while i < n and path[i] not in '/\\': + i = i+1 + if i == 1: + if os.environ.has_key('HOME'): + userhome = os.environ['HOME'] + elif not os.environ.has_key('HOMEPATH'): + return path + else: + try: + drive=os.environ['HOMEDRIVE'] + except KeyError: + drive = '' + userhome = join(drive, os.environ['HOMEPATH']) + else: + return path + return userhome + path[i:] # Expand paths containing shell variable substitutions. # The following rules apply: -# - no expansion within single quotes -# - no escape character, except for '$$' which is translated into '$' -# - ${varname} is accepted. -# - varnames can be made out of letters, digits and the character '_' +# - no expansion within single quotes +# - no escape character, except for '$$' which is translated into '$' +# - ${varname} is accepted. +# - varnames can be made out of letters, digits and the character '_' # XXX With COMMAND.COM you can use any characters in a variable name, # XXX except '^|<>='. varchars = string.letters + string.digits + '_-' -def expandvars(path): - if '$' not in path: - return path - res = '' - index = 0 - pathlen = len(path) - while index < pathlen: - c = path[index] - if c == '\'': # no expansion within single quotes - path = path[index + 1:] - pathlen = len(path) - try: - index = string.index(path, '\'') - res = res + '\'' + path[:index + 1] - except string.index_error: - res = res + path - index = pathlen -1 - elif c == '$': # variable or '$$' - if path[index + 1:index + 2] == '$': - res = res + c - index = index + 1 - elif path[index + 1:index + 2] == '{': - path = path[index+2:] - pathlen = len(path) - try: - index = string.index(path, '}') - var = path[:index] - if os.environ.has_key(var): - res = res + os.environ[var] - except string.index_error: - res = res + path - index = pathlen - 1 - else: - var = '' - index = index + 1 - c = path[index:index + 1] - while c != '' and c in varchars: - var = var + c - index = index + 1 - c = path[index:index + 1] - if os.environ.has_key(var): - res = res + os.environ[var] - if c != '': - res = res + c - else: - res = res + c - index = index + 1 - return res +def expandvars(path): + """Expand shell variables of form $var and ${var}. Unknown variables +are left unchanged""" + if '$' not in path: + return path + res = '' + index = 0 + pathlen = len(path) + while index < pathlen: + c = path[index] + if c == '\'': # no expansion within single quotes + path = path[index + 1:] + pathlen = len(path) + try: + index = string.index(path, '\'') + res = res + '\'' + path[:index + 1] + except string.index_error: + res = res + path + index = pathlen -1 + elif c == '$': # variable or '$$' + if path[index + 1:index + 2] == '$': + res = res + c + index = index + 1 + elif path[index + 1:index + 2] == '{': + path = path[index+2:] + pathlen = len(path) + try: + index = string.index(path, '}') + var = path[:index] + if os.environ.has_key(var): + res = res + os.environ[var] + except string.index_error: + res = res + path + index = pathlen - 1 + else: + var = '' + index = index + 1 + c = path[index:index + 1] + while c != '' and c in varchars: + var = var + c + index = index + 1 + c = path[index:index + 1] + if os.environ.has_key(var): + res = res + os.environ[var] + if c != '': + res = res + c + else: + res = res + c + index = index + 1 + return res # Normalize a path, e.g. A//B, A/./B and A/foo/../B all become A/B. @@ -320,25 +354,25 @@ def expandvars(path): # but as this module is called "ntpath", that's obviously wrong! def normpath(path): - path = normcase(path) - prefix, path = splitdrive(path) - while path[:1] == os.sep: - prefix = prefix + os.sep - path = path[1:] - comps = string.splitfields(path, os.sep) - i = 0 - while i < len(comps): - if comps[i] == '.': - del comps[i] - elif comps[i] == '..' and i > 0 and \ - comps[i-1] not in ('', '..'): - del comps[i-1:i+1] - i = i-1 - elif comps[i] == '' and i > 0 and comps[i-1] <> '': - del comps[i] - else: - i = i+1 - # If the path is now empty, substitute '.' - if not prefix and not comps: - comps.append('.') - return prefix + string.joinfields(comps, os.sep) + """Normalize path, eliminating double slashes, etc.""" + path = normcase(path) + prefix, path = splitdrive(path) + while path[:1] == os.sep: + prefix = prefix + os.sep + path = path[1:] + comps = string.splitfields(path, os.sep) + i = 0 + while i < len(comps): + if comps[i] == '.': + del comps[i] + elif comps[i] == '..' and i > 0 and comps[i-1] not in ('', '..'): + del comps[i-1:i+1] + i = i-1 + elif comps[i] == '' and i > 0 and comps[i-1] <> '': + del comps[i] + else: + i = i+1 + # If the path is now empty, substitute '.' + if not prefix and not comps: + comps.append('.') + return prefix + string.joinfields(comps, os.sep) |