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Diffstat (limited to 'lib/python2.7/posixpath.py')
| -rw-r--r-- | lib/python2.7/posixpath.py | 439 |
1 files changed, 439 insertions, 0 deletions
diff --git a/lib/python2.7/posixpath.py b/lib/python2.7/posixpath.py new file mode 100644 index 0000000..f5c2260 --- /dev/null +++ b/lib/python2.7/posixpath.py @@ -0,0 +1,439 @@ +"""Common operations on Posix pathnames. + +Instead of importing this module directly, import os and refer to +this module as os.path. The "os.path" name is an alias for this +module on Posix systems; on other systems (e.g. Mac, Windows), +os.path provides the same operations in a manner specific to that +platform, and is an alias to another module (e.g. macpath, ntpath). + +Some of this can actually be useful on non-Posix systems too, e.g. +for manipulation of the pathname component of URLs. +""" + +import os +import sys +import stat +import genericpath +import warnings +from genericpath import * +from genericpath import _unicode + +__all__ = ["normcase","isabs","join","splitdrive","split","splitext", + "basename","dirname","commonprefix","getsize","getmtime", + "getatime","getctime","islink","exists","lexists","isdir","isfile", + "ismount","walk","expanduser","expandvars","normpath","abspath", + "samefile","sameopenfile","samestat", + "curdir","pardir","sep","pathsep","defpath","altsep","extsep", + "devnull","realpath","supports_unicode_filenames","relpath"] + +# strings representing various path-related bits and pieces +curdir = '.' +pardir = '..' +extsep = '.' +sep = '/' +pathsep = ':' +defpath = ':/bin:/usr/bin' +altsep = None +devnull = '/dev/null' + +# Normalize the case of a pathname. Trivial in Posix, string.lower on Mac. +# On MS-DOS this may also turn slashes into backslashes; however, other +# normalizations (such as optimizing '../' away) are not allowed +# (another function should be defined to do that). + +def normcase(s): + """Normalize case of pathname. Has no effect under Posix""" + return s + + +# Return whether a path is absolute. +# Trivial in Posix, harder on the Mac or MS-DOS. + +def isabs(s): + """Test whether a path is absolute""" + return s.startswith('/') + + +# Join pathnames. +# Ignore the previous parts if a part is absolute. +# Insert a '/' unless the first part is empty or already ends in '/'. + +def join(a, *p): + """Join two or more pathname components, inserting '/' as needed. + If any component is an absolute path, all previous path components + will be discarded. An empty last part will result in a path that + ends with a separator.""" + path = a + for b in p: + if b.startswith('/'): + path = b + elif path == '' or path.endswith('/'): + path += b + else: + path += '/' + b + return path + + +# Split a path in head (everything up to the last '/') and tail (the +# rest). If the path ends in '/', tail will be empty. If there is no +# '/' in the path, head will be empty. +# Trailing '/'es are stripped from head unless it is the root. + +def split(p): + """Split a pathname. Returns tuple "(head, tail)" where "tail" is + everything after the final slash. Either part may be empty.""" + i = p.rfind('/') + 1 + head, tail = p[:i], p[i:] + if head and head != '/'*len(head): + head = head.rstrip('/') + return head, tail + + +# Split a path in root and extension. +# The extension is everything starting at the last dot in the last +# pathname component; the root is everything before that. +# It is always true that root + ext == p. + +def splitext(p): + return genericpath._splitext(p, sep, altsep, extsep) +splitext.__doc__ = genericpath._splitext.__doc__ + +# Split a pathname into a drive specification and the rest of the +# path. Useful on DOS/Windows/NT; on Unix, the drive is always empty. + +def splitdrive(p): + """Split a pathname into drive and path. On Posix, drive is always + empty.""" + return '', p + + +# Return the tail (basename) part of a path, same as split(path)[1]. + +def basename(p): + """Returns the final component of a pathname""" + i = p.rfind('/') + 1 + return p[i:] + + +# Return the head (dirname) part of a path, same as split(path)[0]. + +def dirname(p): + """Returns the directory component of a pathname""" + i = p.rfind('/') + 1 + head = p[:i] + if head and head != '/'*len(head): + head = head.rstrip('/') + return head + + +# Is a path a symbolic link? +# This will always return false on systems where os.lstat doesn't exist. + +def islink(path): + """Test whether a path is a symbolic link""" + try: + st = os.lstat(path) + except (os.error, AttributeError): + return False + return stat.S_ISLNK(st.st_mode) + +# Being true for dangling symbolic links is also useful. + +def lexists(path): + """Test whether a path exists. Returns True for broken symbolic links""" + try: + os.lstat(path) + except os.error: + return False + return True + + +# Are two filenames really pointing to the same file? + +def samefile(f1, f2): + """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? +# (Not necessarily the same file descriptor!) + +def sameopenfile(fp1, fp2): + """Test whether two open file objects reference the same file""" + s1 = os.fstat(fp1) + s2 = os.fstat(fp2) + return samestat(s1, s2) + + +# Are two stat buffers (obtained from stat, fstat or lstat) +# describing the same file? + +def samestat(s1, s2): + """Test whether two stat buffers reference the same file""" + return s1.st_ino == s2.st_ino and \ + s1.st_dev == s2.st_dev + + +# Is a path a mount point? +# (Does this work for all UNIXes? Is it even guaranteed to work by Posix?) + +def ismount(path): + """Test whether a path is a mount point""" + if islink(path): + # A symlink can never be a mount point + return False + try: + s1 = os.lstat(path) + s2 = os.lstat(realpath(join(path, '..'))) + except os.error: + return False # It doesn't exist -- so not a mount point :-) + dev1 = s1.st_dev + dev2 = s2.st_dev + if dev1 != dev2: + return True # path/.. on a different device as path + ino1 = s1.st_ino + ino2 = s2.st_ino + if ino1 == ino2: + return True # path/.. is the same i-node as path + return False + + +# 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 +# of 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): + """Directory tree walk with callback function. + + For each directory in the directory tree rooted at top (including top + itself, but excluding '.' and '..'), call func(arg, dirname, fnames). + dirname is the name of the directory, and fnames a list of the names of + the files and subdirectories in dirname (excluding '.' and '..'). func + may modify the fnames list in-place (e.g. via del or slice assignment), + and walk will only recurse into the subdirectories whose names remain in + fnames; this can be used to implement a filter, or to impose a specific + order of visiting. No semantics are defined for, or required of, arg, + beyond that arg is always passed to func. It can be used, e.g., to pass + a filename pattern, or a mutable object designed to accumulate + statistics. Passing None for arg is common.""" + warnings.warnpy3k("In 3.x, os.path.walk is removed in favor of os.walk.", + stacklevel=2) + try: + names = os.listdir(top) + except os.error: + return + func(arg, top, names) + for name in names: + name = join(top, name) + try: + st = os.lstat(name) + except os.error: + continue + if stat.S_ISDIR(st.st_mode): + 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.) + +def expanduser(path): + """Expand ~ and ~user constructions. If user or $HOME is unknown, + do nothing.""" + if not path.startswith('~'): + return path + i = path.find('/', 1) + if i < 0: + i = len(path) + if i == 1: + if 'HOME' not in os.environ: + import pwd + userhome = pwd.getpwuid(os.getuid()).pw_dir + else: + userhome = os.environ['HOME'] + else: + import pwd + try: + pwent = pwd.getpwnam(path[1:i]) + except KeyError: + return path + userhome = pwent.pw_dir + userhome = userhome.rstrip('/') + return (userhome + path[i:]) or '/' + + +# Expand paths containing shell variable substitutions. +# This expands the forms $variable and ${variable} only. +# Non-existent variables are left unchanged. + +_varprog = None +_uvarprog = None + +def expandvars(path): + """Expand shell variables of form $var and ${var}. Unknown variables + are left unchanged.""" + global _varprog, _uvarprog + if '$' not in path: + return path + if isinstance(path, _unicode): + if not _uvarprog: + import re + _uvarprog = re.compile(ur'\$(\w+|\{[^}]*\})', re.UNICODE) + varprog = _uvarprog + encoding = sys.getfilesystemencoding() + else: + if not _varprog: + import re + _varprog = re.compile(r'\$(\w+|\{[^}]*\})') + varprog = _varprog + encoding = None + i = 0 + while True: + m = varprog.search(path, i) + if not m: + break + i, j = m.span(0) + name = m.group(1) + if name.startswith('{') and name.endswith('}'): + name = name[1:-1] + if encoding: + name = name.encode(encoding) + if name in os.environ: + tail = path[j:] + value = os.environ[name] + if encoding: + value = value.decode(encoding) + path = path[:i] + value + i = len(path) + path += tail + else: + i = j + return path + + +# Normalize a path, e.g. A//B, A/./B and A/foo/../B all become A/B. +# It should be understood that this may change the meaning of the path +# if it contains symbolic links! + +def normpath(path): + """Normalize path, eliminating double slashes, etc.""" + # Preserve unicode (if path is unicode) + slash, dot = (u'/', u'.') if isinstance(path, _unicode) else ('/', '.') + if path == '': + return dot + initial_slashes = path.startswith('/') + # POSIX allows one or two initial slashes, but treats three or more + # as single slash. + if (initial_slashes and + path.startswith('//') and not path.startswith('///')): + initial_slashes = 2 + comps = path.split('/') + new_comps = [] + for comp in comps: + if comp in ('', '.'): + continue + if (comp != '..' or (not initial_slashes and not new_comps) or + (new_comps and new_comps[-1] == '..')): + new_comps.append(comp) + elif new_comps: + new_comps.pop() + comps = new_comps + path = slash.join(comps) + if initial_slashes: + path = slash*initial_slashes + path + return path or dot + + +def abspath(path): + """Return an absolute path.""" + if not isabs(path): + if isinstance(path, _unicode): + cwd = os.getcwdu() + else: + cwd = os.getcwd() + path = join(cwd, path) + return normpath(path) + + +# Return a canonical path (i.e. the absolute location of a file on the +# filesystem). + +def realpath(filename): + """Return the canonical path of the specified filename, eliminating any +symbolic links encountered in the path.""" + path, ok = _joinrealpath('', filename, {}) + return abspath(path) + +# Join two paths, normalizing and eliminating any symbolic links +# encountered in the second path. +def _joinrealpath(path, rest, seen): + if isabs(rest): + rest = rest[1:] + path = sep + + while rest: + name, _, rest = rest.partition(sep) + if not name or name == curdir: + # current dir + continue + if name == pardir: + # parent dir + if path: + path, name = split(path) + if name == pardir: + path = join(path, pardir, pardir) + else: + path = pardir + continue + newpath = join(path, name) + if not islink(newpath): + path = newpath + continue + # Resolve the symbolic link + if newpath in seen: + # Already seen this path + path = seen[newpath] + if path is not None: + # use cached value + continue + # The symlink is not resolved, so we must have a symlink loop. + # Return already resolved part + rest of the path unchanged. + return join(newpath, rest), False + seen[newpath] = None # not resolved symlink + path, ok = _joinrealpath(path, os.readlink(newpath), seen) + if not ok: + return join(path, rest), False + seen[newpath] = path # resolved symlink + + return path, True + + +supports_unicode_filenames = (sys.platform == 'darwin') + +def relpath(path, start=curdir): + """Return a relative version of a path""" + + if not path: + raise ValueError("no path specified") + + start_list = [x for x in abspath(start).split(sep) if x] + path_list = [x for x in abspath(path).split(sep) if x] + + # Work out how much of the filepath is shared by start and path. + i = len(commonprefix([start_list, path_list])) + + rel_list = [pardir] * (len(start_list)-i) + path_list[i:] + if not rel_list: + return curdir + return join(*rel_list) |