def _remove_os_link():
"""
In a context, remove and restore os.link if it exists
"""
class NoValue:
pass
orig_val = getattr(os, 'link', NoValue)
try:
del os.link
except Exception:
pass
try:
yield
finally:
if orig_val is not NoValue:
setattr(os, 'link', orig_val)
python类link()的实例源码
def makelink(self, tarinfo, targetpath):
"""Make a (symbolic) link called targetpath. If it cannot be created
(platform limitation), we try to make a copy of the referenced file
instead of a link.
"""
try:
# For systems that support symbolic and hard links.
if tarinfo.issym():
os.symlink(tarinfo.linkname, targetpath)
else:
# See extract().
if os.path.exists(tarinfo._link_target):
os.link(tarinfo._link_target, targetpath)
else:
self._extract_member(self._find_link_target(tarinfo),
targetpath)
except symlink_exception:
try:
self._extract_member(self._find_link_target(tarinfo),
targetpath)
except KeyError:
raise ExtractError("unable to resolve link inside archive")
def _find_link_target(self, tarinfo):
"""Find the target member of a symlink or hardlink member in the
archive.
"""
if tarinfo.issym():
# Always search the entire archive.
linkname = "/".join(filter(None, (os.path.dirname(tarinfo.name), tarinfo.linkname)))
limit = None
else:
# Search the archive before the link, because a hard link is
# just a reference to an already archived file.
linkname = tarinfo.linkname
limit = tarinfo
member = self._getmember(linkname, tarinfo=limit, normalize=True)
if member is None:
raise KeyError("linkname %r not found" % linkname)
return member
def _remove_os_link():
"""
In a context, remove and restore os.link if it exists
"""
class NoValue:
pass
orig_val = getattr(os, 'link', NoValue)
try:
del os.link
except Exception:
pass
try:
yield
finally:
if orig_val is not NoValue:
setattr(os, 'link', orig_val)
def __init__(self, name=""):
"""Construct a TarInfo object. name is the optional name
of the member.
"""
self.name = name # member name
self.mode = 0644 # file permissions
self.uid = 0 # user id
self.gid = 0 # group id
self.size = 0 # file size
self.mtime = 0 # modification time
self.chksum = 0 # header checksum
self.type = REGTYPE # member type
self.linkname = "" # link name
self.uname = "" # user name
self.gname = "" # group name
self.devmajor = 0 # device major number
self.devminor = 0 # device minor number
self.offset = 0 # the tar header starts here
self.offset_data = 0 # the file's data starts here
self.pax_headers = {} # pax header information
# In pax headers the "name" and "linkname" field are called
# "path" and "linkpath".
def pack(self):
"""Re-name messages to eliminate numbering gaps. Invalidates keys."""
sequences = self.get_sequences()
prev = 0
changes = []
for key in self.iterkeys():
if key - 1 != prev:
changes.append((key, prev + 1))
if hasattr(os, 'link'):
os.link(os.path.join(self._path, str(key)),
os.path.join(self._path, str(prev + 1)))
os.unlink(os.path.join(self._path, str(key)))
else:
os.rename(os.path.join(self._path, str(key)),
os.path.join(self._path, str(prev + 1)))
prev += 1
self._next_key = prev + 1
if len(changes) == 0:
return
for name, key_list in sequences.items():
for old, new in changes:
if old in key_list:
key_list[key_list.index(old)] = new
self.set_sequences(sequences)
def _remove_os_link():
"""
In a context, remove and restore os.link if it exists
"""
class NoValue:
pass
orig_val = getattr(os, 'link', NoValue)
try:
del os.link
except Exception:
pass
try:
yield
finally:
if orig_val is not NoValue:
setattr(os, 'link', orig_val)
def _remove_os_link():
"""
In a context, remove and restore os.link if it exists
"""
class NoValue:
pass
orig_val = getattr(os, 'link', NoValue)
try:
del os.link
except Exception:
pass
try:
yield
finally:
if orig_val is not NoValue:
setattr(os, 'link', orig_val)
def _find_link_target(self, tarinfo):
"""Find the target member of a symlink or hardlink member in the
archive.
"""
if tarinfo.issym():
# Always search the entire archive.
linkname = os.path.dirname(tarinfo.name) + "/" + tarinfo.linkname
limit = None
else:
# Search the archive before the link, because a hard link is
# just a reference to an already archived file.
linkname = tarinfo.linkname
limit = tarinfo
member = self._getmember(linkname, tarinfo=limit, normalize=True)
if member is None:
raise KeyError("linkname %r not found" % linkname)
return member
def copy(self, target, mode=False):
""" copy path to target."""
if self.check(file=1):
if target.check(dir=1):
target = target.join(self.basename)
assert self!=target
copychunked(self, target)
if mode:
copymode(self.strpath, target.strpath)
else:
def rec(p):
return p.check(link=0)
for x in self.visit(rec=rec):
relpath = x.relto(self)
newx = target.join(relpath)
newx.dirpath().ensure(dir=1)
if x.check(link=1):
newx.mksymlinkto(x.readlink())
continue
elif x.check(file=1):
copychunked(x, newx)
elif x.check(dir=1):
newx.ensure(dir=1)
if mode:
copymode(x.strpath, newx.strpath)
def _find_link_target(self, tarinfo):
"""Find the target member of a symlink or hardlink member in the
archive.
"""
if tarinfo.issym():
# Always search the entire archive.
linkname = os.path.dirname(tarinfo.name) + "/" + tarinfo.linkname
limit = None
else:
# Search the archive before the link, because a hard link is
# just a reference to an already archived file.
linkname = tarinfo.linkname
limit = tarinfo
member = self._getmember(linkname, tarinfo=limit, normalize=True)
if member is None:
raise KeyError("linkname %r not found" % linkname)
return member
def _find_link_target(self, tarinfo):
"""Find the target member of a symlink or hardlink member in the
archive.
"""
if tarinfo.issym():
# Always search the entire archive.
linkname = os.path.dirname(tarinfo.name) + "/" + tarinfo.linkname
limit = None
else:
# Search the archive before the link, because a hard link is
# just a reference to an already archived file.
linkname = tarinfo.linkname
limit = tarinfo
member = self._getmember(linkname, tarinfo=limit, normalize=True)
if member is None:
raise KeyError("linkname %r not found" % linkname)
return member
def __init__(self, name=""):
"""Construct a TarInfo object. name is the optional name
of the member.
"""
self.name = name # member name
self.mode = 0644 # file permissions
self.uid = 0 # user id
self.gid = 0 # group id
self.size = 0 # file size
self.mtime = 0 # modification time
self.chksum = 0 # header checksum
self.type = REGTYPE # member type
self.linkname = "" # link name
self.uname = "" # user name
self.gname = "" # group name
self.devmajor = 0 # device major number
self.devminor = 0 # device minor number
self.offset = 0 # the tar header starts here
self.offset_data = 0 # the file's data starts here
self.pax_headers = {} # pax header information
# In pax headers the "name" and "linkname" field are called
# "path" and "linkpath".
def makelink(self, tarinfo, targetpath):
"""Make a (symbolic) link called targetpath. If it cannot be created
(platform limitation), we try to make a copy of the referenced file
instead of a link.
"""
if hasattr(os, "symlink") and hasattr(os, "link"):
# For systems that support symbolic and hard links.
if tarinfo.issym():
if os.path.lexists(targetpath):
os.unlink(targetpath)
os.symlink(tarinfo.linkname, targetpath)
else:
# See extract().
if os.path.exists(tarinfo._link_target):
if os.path.lexists(targetpath):
os.unlink(targetpath)
os.link(tarinfo._link_target, targetpath)
else:
self._extract_member(self._find_link_target(tarinfo), targetpath)
else:
try:
self._extract_member(self._find_link_target(tarinfo), targetpath)
except KeyError:
raise ExtractError("unable to resolve link inside archive")
def _find_link_target(self, tarinfo):
"""Find the target member of a symlink or hardlink member in the
archive.
"""
if tarinfo.issym():
# Always search the entire archive.
linkname = "/".join(filter(None, (os.path.dirname(tarinfo.name), tarinfo.linkname)))
limit = None
else:
# Search the archive before the link, because a hard link is
# just a reference to an already archived file.
linkname = tarinfo.linkname
limit = tarinfo
member = self._getmember(linkname, tarinfo=limit, normalize=True)
if member is None:
raise KeyError("linkname %r not found" % linkname)
return member
def test_copy_file_hard_link_failure(self):
# If hard linking fails, copy_file() falls back on copying file
# (some special filesystems don't support hard linking even under
# Unix, see issue #8876).
with open(self.source, 'w') as f:
f.write('some content')
st = os.stat(self.source)
def _os_link(*args):
raise OSError(0, "linking unsupported")
old_link = os.link
os.link = _os_link
try:
copy_file(self.source, self.target, link='hard')
finally:
os.link = old_link
st2 = os.stat(self.source)
st3 = os.stat(self.target)
self.assertTrue(os.path.samestat(st, st2), (st, st2))
self.assertFalse(os.path.samestat(st2, st3), (st2, st3))
for fn in (self.source, self.target):
with open(fn, 'r') as f:
self.assertEqual(f.read(), 'some content')
def pack(self):
"""Re-name messages to eliminate numbering gaps. Invalidates keys."""
sequences = self.get_sequences()
prev = 0
changes = []
for key in self.iterkeys():
if key - 1 != prev:
changes.append((key, prev + 1))
if hasattr(os, 'link'):
os.link(os.path.join(self._path, str(key)),
os.path.join(self._path, str(prev + 1)))
os.unlink(os.path.join(self._path, str(key)))
else:
os.rename(os.path.join(self._path, str(key)),
os.path.join(self._path, str(prev + 1)))
prev += 1
self._next_key = prev + 1
if len(changes) == 0:
return
for name, key_list in sequences.items():
for old, new in changes:
if old in key_list:
key_list[key_list.index(old)] = new
self.set_sequences(sequences)
def _find_link_target(self, tarinfo):
"""Find the target member of a symlink or hardlink member in the
archive.
"""
if tarinfo.issym():
# Always search the entire archive.
linkname = os.path.dirname(tarinfo.name) + "/" + tarinfo.linkname
limit = None
else:
# Search the archive before the link, because a hard link is
# just a reference to an already archived file.
linkname = tarinfo.linkname
limit = tarinfo
member = self._getmember(linkname, tarinfo=limit, normalize=True)
if member is None:
raise KeyError("linkname %r not found" % linkname)
return member
def _remove_os_link():
"""
In a context, remove and restore os.link if it exists
"""
class NoValue:
pass
orig_val = getattr(os, 'link', NoValue)
try:
del os.link
except Exception:
pass
try:
yield
finally:
if orig_val is not NoValue:
setattr(os, 'link', orig_val)
def _remove_os_link():
"""
In a context, remove and restore os.link if it exists
"""
class NoValue:
pass
orig_val = getattr(os, 'link', NoValue)
try:
del os.link
except Exception:
pass
try:
yield
finally:
if orig_val is not NoValue:
setattr(os, 'link', orig_val)
def _find_link_target(self, tarinfo):
"""Find the target member of a symlink or hardlink member in the
archive.
"""
if tarinfo.issym():
# Always search the entire archive.
linkname = os.path.dirname(tarinfo.name) + "/" + tarinfo.linkname
limit = None
else:
# Search the archive before the link, because a hard link is
# just a reference to an already archived file.
linkname = tarinfo.linkname
limit = tarinfo
member = self._getmember(linkname, tarinfo=limit, normalize=True)
if member is None:
raise KeyError("linkname %r not found" % linkname)
return member
def _remove_os_link():
"""
In a context, remove and restore os.link if it exists
"""
class NoValue:
pass
orig_val = getattr(os, 'link', NoValue)
try:
del os.link
except Exception:
pass
try:
yield
finally:
if orig_val is not NoValue:
setattr(os, 'link', orig_val)
def safe_make_symlink(input_file_path,output_file_path):
output_file_dir = os.path.dirname(output_file_path)
# Verify the input file is actually there
if not os.path.exists(input_file_path):
raise Exception("can't find file %s"%input_file_path)
safe_make_dirs(output_file_dir)
try:
os.symlink(input_file_path,output_file_path)
except OSError as err:
if err.errno == errno.EEXIST:
# link already exists, check that it is identical to the one we are trying to put down
old = os.path.realpath(input_file_path)
new = os.path.realpath(output_file_path)
if old != new:
raise Exception('Existing file is different than the new symlink')
else:
raise
def _find_link_target(self, tarinfo):
"""Find the target member of a symlink or hardlink member in the
archive.
"""
if tarinfo.issym():
# Always search the entire archive.
linkname = os.path.dirname(tarinfo.name) + "/" + tarinfo.linkname
limit = None
else:
# Search the archive before the link, because a hard link is
# just a reference to an already archived file.
linkname = tarinfo.linkname
limit = tarinfo
member = self._getmember(linkname, tarinfo=limit, normalize=True)
if member is None:
raise KeyError("linkname %r not found" % linkname)
return member
def _remove_os_link():
"""
In a context, remove and restore os.link if it exists
"""
class NoValue:
pass
orig_val = getattr(os, 'link', NoValue)
try:
del os.link
except Exception:
pass
try:
yield
finally:
if orig_val is not NoValue:
setattr(os, 'link', orig_val)
def makelink(self, tarinfo, targetpath):
"""Make a (symbolic) link called targetpath. If it cannot be created
(platform limitation), we try to make a copy of the referenced file
instead of a link.
"""
try:
# For systems that support symbolic and hard links.
if tarinfo.issym():
os.symlink(tarinfo.linkname, targetpath)
else:
# See extract().
if os.path.exists(tarinfo._link_target):
os.link(tarinfo._link_target, targetpath)
else:
self._extract_member(self._find_link_target(tarinfo),
targetpath)
except symlink_exception:
try:
self._extract_member(self._find_link_target(tarinfo),
targetpath)
except KeyError:
raise ExtractError("unable to resolve link inside archive")
def _find_link_target(self, tarinfo):
"""Find the target member of a symlink or hardlink member in the
archive.
"""
if tarinfo.issym():
# Always search the entire archive.
linkname = "/".join(filter(None, (os.path.dirname(tarinfo.name), tarinfo.linkname)))
limit = None
else:
# Search the archive before the link, because a hard link is
# just a reference to an already archived file.
linkname = tarinfo.linkname
limit = tarinfo
member = self._getmember(linkname, tarinfo=limit, normalize=True)
if member is None:
raise KeyError("linkname %r not found" % linkname)
return member
def _find_link_target(self, tarinfo):
"""Find the target member of a symlink or hardlink member in the
archive.
"""
if tarinfo.issym():
# Always search the entire archive.
linkname = os.path.dirname(tarinfo.name) + "/" + tarinfo.linkname
limit = None
else:
# Search the archive before the link, because a hard link is
# just a reference to an already archived file.
linkname = tarinfo.linkname
limit = tarinfo
member = self._getmember(linkname, tarinfo=limit, normalize=True)
if member is None:
raise KeyError("linkname %r not found" % linkname)
return member
def _remove_os_link():
"""
In a context, remove and restore os.link if it exists
"""
class NoValue:
pass
orig_val = getattr(os, 'link', NoValue)
try:
del os.link
except Exception:
pass
try:
yield
finally:
if orig_val is not NoValue:
setattr(os, 'link', orig_val)
def acquire(self, timeout=None):
try:
open(self.unique_name, "wb").close()
except IOError:
raise LockFailed("failed to create %s" % self.unique_name)
timeout = timeout if timeout is not None else self.timeout
end_time = time.time()
if timeout is not None and timeout > 0:
end_time += timeout
while True:
# Try and create a hard link to it.
try:
os.link(self.unique_name, self.lock_file)
except OSError:
# Link creation failed. Maybe we've double-locked?
nlinks = os.stat(self.unique_name).st_nlink
if nlinks == 2:
# The original link plus the one I created == 2. We're
# good to go.
return
else:
# Otherwise the lock creation failed.
if timeout is not None and time.time() > end_time:
os.unlink(self.unique_name)
if timeout > 0:
raise LockTimeout("Timeout waiting to acquire"
" lock for %s" %
self.path)
else:
raise AlreadyLocked("%s is already locked" %
self.path)
time.sleep(timeout is not None and timeout / 10 or 0.1)
else:
# Link creation succeeded. We're good to go.
return
