From c527fd1f14c27855a37f2e8ac5346ce8d940ced2 Mon Sep 17 00:00:00 2001 From: Tudor Florea Date: Thu, 16 Oct 2014 03:05:19 +0200 Subject: initial commit for Enea Linux 4.0-140929 Migrated from the internal git server on the daisy-enea-point-release branch Signed-off-by: Tudor Florea --- meta/lib/oe/cachedpath.py | 233 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 233 insertions(+) create mode 100644 meta/lib/oe/cachedpath.py (limited to 'meta/lib/oe/cachedpath.py') diff --git a/meta/lib/oe/cachedpath.py b/meta/lib/oe/cachedpath.py new file mode 100644 index 0000000000..0840cc4c3f --- /dev/null +++ b/meta/lib/oe/cachedpath.py @@ -0,0 +1,233 @@ +# +# Based on standard python library functions but avoid +# repeated stat calls. Its assumed the files will not change from under us +# so we can cache stat calls. +# + +import os +import errno +import stat as statmod + +class CachedPath(object): + def __init__(self): + self.statcache = {} + self.lstatcache = {} + self.normpathcache = {} + return + + def updatecache(self, x): + x = self.normpath(x) + if x in self.statcache: + del self.statcache[x] + if x in self.lstatcache: + del self.lstatcache[x] + + def normpath(self, path): + if path in self.normpathcache: + return self.normpathcache[path] + newpath = os.path.normpath(path) + self.normpathcache[path] = newpath + return newpath + + def _callstat(self, path): + if path in self.statcache: + return self.statcache[path] + try: + st = os.stat(path) + self.statcache[path] = st + return st + except os.error: + self.statcache[path] = False + return False + + # We might as well call lstat and then only + # call stat as well in the symbolic link case + # since this turns out to be much more optimal + # in real world usage of this cache + def callstat(self, path): + path = self.normpath(path) + self.calllstat(path) + return self.statcache[path] + + def calllstat(self, path): + path = self.normpath(path) + if path in self.lstatcache: + return self.lstatcache[path] + #bb.error("LStatpath:" + path) + try: + lst = os.lstat(path) + self.lstatcache[path] = lst + if not statmod.S_ISLNK(lst.st_mode): + self.statcache[path] = lst + else: + self._callstat(path) + return lst + except (os.error, AttributeError): + self.lstatcache[path] = False + self.statcache[path] = False + return False + + # This follows symbolic links, so both islink() and isdir() can be true + # for the same path ono systems that support symlinks + def isfile(self, path): + """Test whether a path is a regular file""" + st = self.callstat(path) + if not st: + return False + return statmod.S_ISREG(st.st_mode) + + # Is a path a directory? + # This follows symbolic links, so both islink() and isdir() + # can be true for the same path on systems that support symlinks + def isdir(self, s): + """Return true if the pathname refers to an existing directory.""" + st = self.callstat(s) + if not st: + return False + return statmod.S_ISDIR(st.st_mode) + + def islink(self, path): + """Test whether a path is a symbolic link""" + st = self.calllstat(path) + if not st: + return False + return statmod.S_ISLNK(st.st_mode) + + # Does a path exist? + # This is false for dangling symbolic links on systems that support them. + def exists(self, path): + """Test whether a path exists. Returns False for broken symbolic links""" + if self.callstat(path): + return True + return False + + def lexists(self, path): + """Test whether a path exists. Returns True for broken symbolic links""" + if self.calllstat(path): + return True + return False + + def stat(self, path): + return self.callstat(path) + + def lstat(self, path): + return self.calllstat(path) + + def walk(self, top, topdown=True, onerror=None, followlinks=False): + # Matches os.walk, not os.path.walk() + + # We may not have read permission for top, in which case we can't + # get a list of the files the directory contains. os.path.walk + # always suppressed the exception then, rather than blow up for a + # minor reason when (say) a thousand readable directories are still + # left to visit. That logic is copied here. + try: + names = os.listdir(top) + except os.error as err: + if onerror is not None: + onerror(err) + return + + dirs, nondirs = [], [] + for name in names: + if self.isdir(os.path.join(top, name)): + dirs.append(name) + else: + nondirs.append(name) + + if topdown: + yield top, dirs, nondirs + for name in dirs: + new_path = os.path.join(top, name) + if followlinks or not self.islink(new_path): + for x in self.walk(new_path, topdown, onerror, followlinks): + yield x + if not topdown: + yield top, dirs, nondirs + + ## realpath() related functions + def __is_path_below(self, file, root): + return (file + os.path.sep).startswith(root) + + def __realpath_rel(self, start, rel_path, root, loop_cnt, assume_dir): + """Calculates real path of symlink 'start' + 'rel_path' below + 'root'; no part of 'start' below 'root' must contain symlinks. """ + have_dir = True + + for d in rel_path.split(os.path.sep): + if not have_dir and not assume_dir: + raise OSError(errno.ENOENT, "no such directory %s" % start) + + if d == os.path.pardir: # '..' + if len(start) >= len(root): + # do not follow '..' before root + start = os.path.dirname(start) + else: + # emit warning? + pass + else: + (start, have_dir) = self.__realpath(os.path.join(start, d), + root, loop_cnt, assume_dir) + + assert(self.__is_path_below(start, root)) + + return start + + def __realpath(self, file, root, loop_cnt, assume_dir): + while self.islink(file) and len(file) >= len(root): + if loop_cnt == 0: + raise OSError(errno.ELOOP, file) + + loop_cnt -= 1 + target = os.path.normpath(os.readlink(file)) + + if not os.path.isabs(target): + tdir = os.path.dirname(file) + assert(self.__is_path_below(tdir, root)) + else: + tdir = root + + file = self.__realpath_rel(tdir, target, root, loop_cnt, assume_dir) + + try: + is_dir = self.isdir(file) + except: + is_dir = False + + return (file, is_dir) + + def realpath(self, file, root, use_physdir = True, loop_cnt = 100, assume_dir = False): + """ Returns the canonical path of 'file' with assuming a + toplevel 'root' directory. When 'use_physdir' is set, all + preceding path components of 'file' will be resolved first; + this flag should be set unless it is guaranteed that there is + no symlink in the path. When 'assume_dir' is not set, missing + path components will raise an ENOENT error""" + + root = os.path.normpath(root) + file = os.path.normpath(file) + + if not root.endswith(os.path.sep): + # letting root end with '/' makes some things easier + root = root + os.path.sep + + if not self.__is_path_below(file, root): + raise OSError(errno.EINVAL, "file '%s' is not below root" % file) + + try: + if use_physdir: + file = self.__realpath_rel(root, file[(len(root) - 1):], root, loop_cnt, assume_dir) + else: + file = self.__realpath(file, root, loop_cnt, assume_dir)[0] + except OSError as e: + if e.errno == errno.ELOOP: + # make ELOOP more readable; without catching it, there will + # be printed a backtrace with 100s of OSError exceptions + # else + raise OSError(errno.ELOOP, + "too much recursions while resolving '%s'; loop in '%s'" % + (file, e.strerror)) + + raise + + return file -- cgit v1.2.3-54-g00ecf