diff options
Diffstat (limited to 'Lib/dospath.py')
| -rw-r--r-- | Lib/dospath.py | 458 |
1 files changed, 227 insertions, 231 deletions
diff --git a/Lib/dospath.py b/Lib/dospath.py index bd5e560..2ad21f0 100644 --- a/Lib/dospath.py +++ b/Lib/dospath.py @@ -1,64 +1,64 @@ -# Module 'dospath' -- common operations on DOS pathnames +"""Module 'dospath' -- common operations on DOS pathnames""" import os import stat import string -# Normalize the case of a pathname. -# On MS-DOS it maps the pathname to lowercase, turns slashes into -# backslashes. -# Other normalizations (such as optimizing '../' away) are not allowed -# (this is done by normpath). -# Previously, this version mapped invalid consecutive characters to a -# single '_', but this has been removed. This functionality should -# possibly be added as a new function. - def normcase(s): - return string.lower(string.replace(s, "/", "\\")) + """Normalize the case of a pathname. + On MS-DOS it maps the pathname to lowercase, turns slashes into + backslashes. + Other normalizations (such as optimizing '../' away) are not allowed + (this is done by normpath). + Previously, this version mapped invalid consecutive characters to a + single '_', but this has been removed. This functionality should + possibly be added as a new function.""" + return string.lower(string.replace(s, "/", "\\")) -# Return wheter a path is absolute. -# Trivial in Posix, harder on the Mac or MS-DOS. -# For DOS it is absolute if it starts with a slash or backslash (current -# volume), or if a pathname after the volume letter and colon starts with -# a slash or backslash. def isabs(s): - s = splitdrive(s)[1] - return s != '' and s[:1] in '/\\' + """Return whether a path is absolute. + Trivial in Posix, harder on the Mac or MS-DOS. + For DOS it is absolute if it starts with a slash or backslash (current + volume), or if a pathname after the volume letter and colon starts with + a slash or backslash.""" + 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) paths.""" + 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 path into a drive specification (a drive letter followed + by a colon) and path specification. + It is always true that drivespec + pathspec == p.""" + 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 -# rest). After the trailing '/' is stripped, the invariant -# join(head, tail) == p holds. -# The resulting head won't end in '/' unless it is the root. def split(p): + """Split a path into head (everything up to the last '/') and tail + (the rest). After the trailing '/' is stripped, the invariant + join(head, tail) == p holds. + The resulting head won't end in '/' unless it is the root.""" + d, p = splitdrive(p) # set i to index beyond p's last slash i = len(p) @@ -73,47 +73,47 @@ def split(p): return d + head, tail -# Split a path in root and extension. -# The extension is everything starting at the first dot in the last -# pathname component; the root is everything before that. -# 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 == '.' or ext: - ext = ext + c - else: - root = root + c - return root, ext + """Split a path into root and extension. + The extension is everything starting at the first dot in the last + pathname component; the root is everything before that. + It is always true that root + ext == p.""" + + root, ext = '', '' + for c in p: + if c in '/\\': + root, ext = root + ext + c, '' + elif c == '.' or 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] + """Return the tail (basename) part of a path.""" + return split(p)[1] -# Return the head (dirname) part of a path. def dirname(p): - return split(p)[0] + """Return the head (dirname) part of a path.""" + 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 + """Return the longest prefix of all list elements.""" + + 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 # Get size, mtime, atime of files. @@ -134,200 +134,196 @@ def getatime(filename): return st[stat.ST_MTIME] -# Is a path a symbolic link? -# This will always return false on systems where posix.lstat doesn't exist. - def islink(path): - return 0 + """Is a path a symbolic link? + This will always return false on systems where posix.lstat doesn't exist.""" + 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 + """Does a path exist? + This is false for dangling symbolic links.""" + try: + st = os.stat(path) + except os.error: + return 0 + return 1 -# Is a path a dos directory? -# This follows symbolic links, so both islink() and isdir() can be true -# 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]) + """Is a path a dos 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? -# This follows symbolic links, so both islink() and isdir() can be true -# 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]) + """Is a path a regular file?""" + try: + st = os.stat(path) + except os.error: + return 0 + return stat.S_ISREG(st[stat.ST_MODE]) -# Is a path a mount point? -# XXX This degenerates in: 'is this the root?' on DOS def ismount(path): - return isabs(splitdrive(path)[1]) + """Is a path a mount point?""" + # XXX This degenerates in: 'is this the root?' on DOS + return isabs(splitdrive(path)[1]) -# Directory tree walk. -# For each directory under top (including top itself, but excluding -# '.' and '..'), func(arg, dirname, filenames) is called, where -# dirname is the name of the directory and filenames is the list -# files files (and subdirectories etc.) in the directory. -# The func may modify the filenames list, to implement a filter, -# 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) - - -# Expand paths beginning with '~' or '~user'. -# '~' means $HOME; '~user' means that user's home directory. -# If the path doesn't begin with '~', or if the user or $HOME is unknown, -# the path is returned unchanged (leaving error reporting to whatever -# function is called with the expanded path as argument). -# See also module 'glob' for expansion of *, ? and [...] in pathnames. -# (A function should also be defined to do full *sh-style environment -# variable expansion.) + """Directory tree walk. + For each directory under top (including top itself, but excluding + '.' and '..'), func(arg, dirname, filenames) is called, where + dirname is the name of the directory and filenames is the list + files files (and subdirectories etc.) in the directory. + The func may modify the filenames list, to implement a filter, + or to impose a different order of visiting.""" + + 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) + 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 not os.environ.has_key('HOME'): - return path - userhome = os.environ['HOME'] - 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 '$$' which is translated into '$' -# - ${varname} is accepted. -# - varnames can be made out of letters, digits and the character '_' -# XXX With COMMAND.COM you can use any characters in a variable name, -# XXX except '^|<>='. + """Expand paths beginning with '~' or '~user'. + '~' means $HOME; '~user' means that user's home directory. + If the path doesn't begin with '~', or if the user or $HOME is unknown, + the path is returned unchanged (leaving error reporting to whatever + function is called with the expanded path as argument). + See also module 'glob' for expansion of *, ? and [...] in pathnames. + (A function should also be defined to do full *sh-style environment + variable expansion.)""" + + if path[:1] <> '~': + return path + i, n = 1, len(path) + while i < n and path[i] not in '/\\': + i = i+1 + if i == 1: + if not os.environ.has_key('HOME'): + return path + userhome = os.environ['HOME'] + else: + return path + return userhome + path[i:] + varchars = string.letters + string.digits + '_-' def expandvars(path): - if '$' not in path: - return path - res = '' - index = 0 - pathlen = len(path) - while index < pathlen: - c = path[index] - if c == '\'': # no expansion within single quotes - path = path[index + 1:] - pathlen = len(path) - try: - index = string.index(path, '\'') - res = res + '\'' + path[:index + 1] - except string.index_error: - res = res + path - index = pathlen -1 - elif c == '$': # variable or '$$' - 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 - - -# Normalize a path, e.g. A//B, A/./B and A/foo/../B all become A/B. -# Also, components of the path are silently truncated to 8+3 notation. + """Expand paths containing shell variable substitutions. + The following rules apply: + - no expansion within single quotes + - no escape character, except for '$$' which is translated into '$' + - ${varname} is accepted. + - varnames can be made out of letters, digits and the character '_'""" + # XXX With COMMAND.COM you can use any characters in a variable name, + # XXX except '^|<>='. + + if '$' not in path: + return path + res = '' + index = 0 + pathlen = len(path) + while index < pathlen: + c = path[index] + if c == '\'': # no expansion within single quotes + path = path[index + 1:] + pathlen = len(path) + try: + index = string.index(path, '\'') + res = res + '\'' + path[:index + 1] + except string.index_error: + res = res + path + index = pathlen -1 + elif c == '$': # variable or '$$' + 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 normpath(path): - path = string.replace(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] - elif '.' in comps[i]: - comp = string.splitfields(comps[i], '.') - comps[i] = comp[0][:8] + '.' + comp[1][:3] - i = i+1 - elif len(comps[i]) > 8: - comps[i] = comps[i][:8] - i = i+1 - 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) - - - -# Return an absolute path. + """Normalize a path, e.g. A//B, A/./B and A/foo/../B all become A/B. + Also, components of the path are silently truncated to 8+3 notation.""" + + path = string.replace(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] + elif '.' in comps[i]: + comp = string.splitfields(comps[i], '.') + comps[i] = comp[0][:8] + '.' + comp[1][:3] + i = i+1 + elif len(comps[i]) > 8: + comps[i] = comps[i][:8] + i = i+1 + 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) + + + def abspath(path): + """Return an absolute path.""" if not isabs(path): path = join(os.getcwd(), path) return normpath(path) |