completely rewrite file based property handling

Signed-off-by: Steven Armstrong <steven@icarus.ethz.ch>
This commit is contained in:
Steven Armstrong 2011-10-14 01:15:08 +02:00
parent be02dc5ff1
commit ede35ffd73

View file

@ -98,55 +98,6 @@ class FileList(collections.MutableSequence):
self.__write(lines)
class FileListProperty(FileList):
def __init__(self, path):
"""
:param path: string or callable
Usage:
class Foo(object):
parameters = DirectoryDictProperty(lambda obj: os.path.join(obj.absolute_path, 'parameter'))
other_dict = DirectoryDictProperty('/tmp/folder')
def __init__(self):
self.absolute_path = '/tmp/foo'
"""
self.path = None
self.__path = path
def _set_path(self, *args, **kwargs):
if self.path is None:
path = self.__path
if callable(path):
path = path(*args, **kwargs)
if not os.path.isabs(path):
raise AbsolutePathRequiredError(path)
self.path = path
# Descriptor Protocol
def __get__(self, obj, objtype=None):
if obj is None:
return self.__class__
self._set_path(obj)
return self
def __set__(self, obj, value):
self._set_path(obj)
try:
os.unlink(self.path)
except EnvironmentError:
# ignored
pass
for item in value:
self.append(item)
def __delete__(self, obj):
raise AttributeError("can't delete attribute")
class DirectoryDict(collections.MutableMapping):
"""A dict that stores it's items as files in a directory.
@ -178,7 +129,10 @@ class DirectoryDict(collections.MutableMapping):
fd.write(str(value))
def __delitem__(self, key):
os.remove(os.path.join(self.path, key))
try:
os.remove(os.path.join(self.path, key))
except EnvironmentError:
raise KeyError(key)
def __iter__(self):
return iter(os.listdir(self.path))
@ -187,95 +141,98 @@ class DirectoryDict(collections.MutableMapping):
return len(os.listdir(self.path))
class DirectoryDictProperty(DirectoryDict):
class FileBasedProperty(object):
attribute_class = None
def __init__(self, path):
"""
:param path: string or callable
Usage:
Abstract super class. Subclass and set the class member attribute_class accordingly.
Usage with a sublcass:
class Foo(object):
parameters = DirectoryDictProperty(lambda obj: os.path.join(obj.absolute_path, 'parameter'))
other_dict = DirectoryDictProperty('/tmp/folder')
# note that the actual DirectoryDict is stored as __parameters on the instance
parameters = DirectoryDictProperty(lambda instance: os.path.join(instance.absolute_path, 'parameter'))
# note that the actual DirectoryDict is stored as __other_dict on the instance
other_dict = DirectoryDictProperty('/tmp/other_dict')
def __init__(self):
self.absolute_path = '/tmp/foo'
"""
self.path = None
self.__path = path
self.path = path
def _set_path(self, *args, **kwargs):
#print("_set_path: self: %s" % self)
print("_set_path: args: %s" % args)
print("_set_path: kwargs: %s" % kwargs)
print("_set_path: self.path: %s" % self.path)
if self.path is None:
path = self.__path
if callable(path):
path = path(*args, **kwargs)
print("_set_path: %s" % path)
if not os.path.isabs(path):
raise AbsolutePathRequiredError(path)
# create directory if it doesn't exist
print("os.path.isdir(%s): %s" % (path, os.path.isdir(path)))
if not os.path.isdir(path):
os.mkdir(path)
self.path = path
def _get_path(self, instance):
path = self.path
if callable(path):
path = path(instance)
return path
# Descriptor Protocol
def __get__(self, obj, objtype=None):
if obj is None:
return self.__class__
self._set_path(obj)
return self
def _get_property_name(self, owner):
for name, prop in owner.__dict__.items():
if self == prop:
return name
def __set__(self, obj, value):
self._set_path(obj)
if value is not None:
for name in self.keys():
del self[name]
self.update(value)
def _get_attribute(self, instance, owner):
name = self._get_property_name(owner)
attribute_name = '__%s' % name
if not hasattr(instance, attribute_name):
path = self._get_path(instance)
attribute_instance = self.attribute_class(path)
setattr(instance, attribute_name, attribute_instance)
return getattr(instance, attribute_name)
def __delete__(self, obj):
def __get__(self, instance, owner):
if instance is None:
return self
return self._get_attribute(instance, owner)
def __delete__(self, instance):
raise AttributeError("can't delete attribute")
class FileBooleanProperty(object):
def __init__(self, path):
"""
:param path: string or callable
class DirectoryDictProperty(FileBasedProperty):
attribute_class = DirectoryDict
Usage:
def __set__(self, instance, value):
attribute_instance = self._get_attribute(instance, instance.__class__)
for name in attribute_instance.keys():
del attribute_instance[name]
attribute_instance.update(value)
class Foo(object):
changed = FileBoolean(lambda obj: os.path.join(obj.absolute_path, 'changed'))
other_boolean = FileBoolean('/tmp/other_boolean')
def __init__(self):
self.absolute_path = '/tmp/foo_boolean'
class FileListProperty(FileBasedProperty):
attribute_class = FileList
"""
self._path = path
def __set__(self, instance, value):
path = self._get_path(instance)
try:
os.unlink(path)
except EnvironmentError:
# ignored
pass
attribute_instance = self._get_attribute(instance, instance.__class__)
for item in value:
attribute_instance.append(item)
def _get_path(self, *args, **kwargs):
path = self._path
if callable(path):
return path(*args, **kwargs)
if not os.path.isabs(path):
raise AbsolutePathRequiredError(path)
return path
class FileBooleanProperty(FileBasedProperty):
"""A boolean property which uses a file to represent its value.
File exists -> True
File does not exists -> False
"""
# Descriptor Protocol
def __get__(self, obj, objtype=None):
if obj is None:
return self.__class__
path = self._get_path(obj)
def __get__(self, instance, owner):
if instance is None:
return self
path = self._get_path(instance)
return os.path.isfile(path)
def __set__(self, obj, value):
path = self._get_path(obj)
def __set__(self, instance, value):
path = self._get_path(instance)
if value:
open(path, "w").close()
else:
@ -285,42 +242,15 @@ class FileBooleanProperty(object):
# ignore
pass
def __delete__(self, obj):
raise AttributeError("can't delete attribute")
class FileStringProperty(object):
class FileStringProperty(FileBasedProperty):
"""A string property which stores its value in a file.
"""
def __init__(self, path):
"""
:param path: string or callable
Usage:
class Foo(object):
source = FileStringProperty(lambda obj: os.path.join(obj.absolute_path, 'source'))
other = FileStringProperty('/tmp/other')
def __init__(self):
self.absolute_path = '/tmp/foo_boolean'
"""
self._path = path
def _get_path(self, *args, **kwargs):
path = self._path
if callable(path):
return path(*args, **kwargs)
if not os.path.isabs(path):
raise AbsolutePathRequiredError(path)
return path
# Descriptor Protocol
def __get__(self, obj, objtype=None):
if obj is None:
return self.__class__
path = self._get_path(obj)
def __get__(self, instance, owner):
if instance is None:
return self
path = self._get_path(instance)
value = ""
try:
with open(path, "r") as fd:
@ -329,16 +259,13 @@ class FileStringProperty(object):
pass
return value
def __set__(self, obj, value):
path = self._get_path(obj)
def __set__(self, instance, value):
path = self._get_path(instance)
if value:
with open(path, "w") as fd:
fd.write(str(value))
else:
try:
os.unlink(path)
os.remove(path)
except EnvironmentError:
pass
def __delete__(self, obj):
raise AttributeError("Can't delete attribute. Set it's value to an empty string to remove the underlying file.")