def remove_if_equals(self, name, old_ref):
"""Remove a refname only if it currently equals old_ref.
This method does not follow symbolic references. It can be used to
perform an atomic compare-and-delete operation.
:param name: The refname to delete.
:param old_ref: The old sha the refname must refer to, or None to delete
unconditionally.
:return: True if the delete was successful, False otherwise.
"""
self._check_refname(name)
filename = self.refpath(name)
ensure_dir_exists(os.path.dirname(filename))
f = GitFile(filename, 'wb')
try:
if old_ref is not None:
orig_ref = self.read_loose_ref(name)
if orig_ref is None:
orig_ref = self.get_packed_refs().get(name, None)
if orig_ref != old_ref:
return False
# may only be packed
try:
os.remove(filename)
except OSError, e:
if e.errno != errno.ENOENT:
raise
self._remove_packed_ref(name)
def add_if_new(self, name, ref):
"""Add a new reference only if it does not already exist.
This method follows symrefs, and only ensures that the last ref in the
chain does not exist.
:param name: The refname to set.
:param ref: The new sha the refname will refer to.
:return: True if the add was successful, False otherwise.
"""
try:
realname, contents = self._follow(name)
if contents is not None:
return False
except KeyError:
realname = name
self._check_refname(realname)
filename = self.refpath(realname)
ensure_dir_exists(os.path.dirname(filename))
f = GitFile(filename, 'wb')
try:
if os.path.exists(filename) or name in self.get_packed_refs():
f.abort()
return False
try:
f.write(ref+"\n")
except (OSError, IOError):
f.abort()
raise
finally:
f.close()
return True
def remove_if_equals(self, name, old_ref):
"""Remove a refname only if it currently equals old_ref.
This method does not follow symbolic references. It can be used to
perform an atomic compare-and-delete operation.
:param name: The refname to delete.
:param old_ref: The old sha the refname must refer to, or None to delete
unconditionally.
:return: True if the delete was successful, False otherwise.
"""
self._check_refname(name)
filename = self.refpath(name)
ensure_dir_exists(os.path.dirname(filename))
f = GitFile(filename, 'wb')
try:
if old_ref is not None:
orig_ref = self.read_loose_ref(name)
if orig_ref is None:
orig_ref = self.get_packed_refs().get(name, None)
if orig_ref != old_ref:
return False
# may only be packed
try:
os.remove(filename)
except OSError, e:
if e.errno != errno.ENOENT:
raise
self._remove_packed_ref(name)
def add_if_new(self, name, ref):
"""Add a new reference only if it does not already exist.
This method follows symrefs, and only ensures that the last ref in the
chain does not exist.
:param name: The refname to set.
:param ref: The new sha the refname will refer to.
:return: True if the add was successful, False otherwise.
"""
try:
realname, contents = self._follow(name)
if contents is not None:
return False
except KeyError:
realname = name
self._check_refname(realname)
filename = self.refpath(realname)
ensure_dir_exists(os.path.dirname(filename))
f = GitFile(filename, 'wb')
try:
if os.path.exists(filename) or name in self.get_packed_refs():
f.abort()
return False
try:
f.write(ref + "\n")
except (OSError, IOError):
f.abort()
raise
finally:
f.close()
return True
def set_if_equals(self, name, old_ref, new_ref):
"""Set a refname to new_ref only if it currently equals old_ref.
This method follows all symbolic references, and can be used to perform
an atomic compare-and-swap operation.
:param name: The refname to set.
:param old_ref: The old sha the refname must refer to, or None to set
unconditionally.
:param new_ref: The new sha the refname will refer to.
:return: True if the set was successful, False otherwise.
"""
try:
realname, _ = self._follow(name)
except KeyError:
realname = name
filename = self.refpath(realname)
ensure_dir_exists(os.path.dirname(filename))
f = GitFile(filename, 'wb')
try:
if old_ref is not None:
try:
# read again while holding the lock
orig_ref = self.read_loose_ref(realname)
if orig_ref is None:
orig_ref = self.get_packed_refs().get(realname, None)
if orig_ref != old_ref:
f.abort()
return False
except (OSError, IOError):
f.abort()
raise
try:
f.write(new_ref+"\n")
except (OSError, IOError):
f.abort()
raise
finally:
f.close()
return True
def set_if_equals(self, name, old_ref, new_ref):
"""Set a refname to new_ref only if it currently equals old_ref.
This method follows all symbolic references, and can be used to perform
an atomic compare-and-swap operation.
:param name: The refname to set.
:param old_ref: The old sha the refname must refer to, or None to set
unconditionally.
:param new_ref: The new sha the refname will refer to.
:return: True if the set was successful, False otherwise.
"""
try:
realname, _ = self._follow(name)
except KeyError:
realname = name
filename = self.refpath(realname)
ensure_dir_exists(os.path.dirname(filename))
f = GitFile(filename, 'wb')
try:
if old_ref is not None:
try:
# read again while holding the lock
orig_ref = self.read_loose_ref(realname)
if orig_ref is None:
orig_ref = self.get_packed_refs().get(realname, None)
if orig_ref != old_ref:
f.abort()
return False
except (OSError, IOError):
f.abort()
raise
try:
f.write(new_ref + "\n")
except (OSError, IOError):
f.abort()
raise
finally:
f.close()
return True
