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pickleutil.py
281 lines | 7.6 KiB | text/x-python | PythonLexer
# encoding: utf-8
"""Pickle related utilities. Perhaps this should be called 'can'."""
__docformat__ = "restructuredtext en"
#-------------------------------------------------------------------------------
# Copyright (C) 2008-2011 The IPython Development Team
#
# Distributed under the terms of the BSD License. The full license is in
# the file COPYING, distributed as part of this software.
#-------------------------------------------------------------------------------
#-------------------------------------------------------------------------------
# Imports
#-------------------------------------------------------------------------------
import copy
import logging
import sys
from types import FunctionType
try:
import cPickle as pickle
except ImportError:
import pickle
try:
import numpy
except:
numpy = None
import codeutil
import py3compat
from importstring import import_item
from IPython.config import Application
if py3compat.PY3:
buffer = memoryview
#-------------------------------------------------------------------------------
# Classes
#-------------------------------------------------------------------------------
class CannedObject(object):
def __init__(self, obj, keys=[]):
self.keys = keys
self.obj = copy.copy(obj)
for key in keys:
setattr(self.obj, key, can(getattr(obj, key)))
self.buffers = []
def get_object(self, g=None):
if g is None:
g = {}
for key in self.keys:
setattr(self.obj, key, uncan(getattr(self.obj, key), g))
return self.obj
class Reference(CannedObject):
"""object for wrapping a remote reference by name."""
def __init__(self, name):
if not isinstance(name, basestring):
raise TypeError("illegal name: %r"%name)
self.name = name
self.buffers = []
def __repr__(self):
return "<Reference: %r>"%self.name
def get_object(self, g=None):
if g is None:
g = {}
return eval(self.name, g)
class CannedFunction(CannedObject):
def __init__(self, f):
self._check_type(f)
self.code = f.func_code
if f.func_defaults:
self.defaults = [ can(fd) for fd in f.func_defaults ]
else:
self.defaults = None
self.module = f.__module__ or '__main__'
self.__name__ = f.__name__
self.buffers = []
def _check_type(self, obj):
assert isinstance(obj, FunctionType), "Not a function type"
def get_object(self, g=None):
# try to load function back into its module:
if not self.module.startswith('__'):
try:
__import__(self.module)
except ImportError:
pass
else:
g = sys.modules[self.module].__dict__
if g is None:
g = {}
if self.defaults:
defaults = tuple(uncan(cfd, g) for cfd in self.defaults)
else:
defaults = None
newFunc = FunctionType(self.code, g, self.__name__, defaults)
return newFunc
class CannedArray(CannedObject):
def __init__(self, obj):
self.shape = obj.shape
self.dtype = obj.dtype.descr if obj.dtype.fields else obj.dtype.str
if sum(obj.shape) == 0:
# just pickle it
self.buffers = [pickle.dumps(obj, -1)]
else:
# ensure contiguous
obj = numpy.ascontiguousarray(obj, dtype=None)
self.buffers = [buffer(obj)]
def get_object(self, g=None):
data = self.buffers[0]
if sum(self.shape) == 0:
# no shape, we just pickled it
return pickle.loads(data)
else:
return numpy.frombuffer(data, dtype=self.dtype).reshape(self.shape)
class CannedBytes(CannedObject):
wrap = bytes
def __init__(self, obj):
self.buffers = [obj]
def get_object(self, g=None):
data = self.buffers[0]
return self.wrap(data)
def CannedBuffer(CannedBytes):
wrap = buffer
#-------------------------------------------------------------------------------
# Functions
#-------------------------------------------------------------------------------
def _logger():
"""get the logger for the current Application
the root logger will be used if no Application is running
"""
if Application.initialized():
logger = Application.instance().log
else:
logger = logging.getLogger()
if not logger.handlers:
logging.basicConfig()
return logger
def _import_mapping(mapping, original=None):
"""import any string-keys in a type mapping
"""
log = _logger()
log.debug("Importing canning map")
for key,value in mapping.items():
if isinstance(key, basestring):
try:
cls = import_item(key)
except Exception:
if original and key not in original:
# only message on user-added classes
log.error("cannning class not importable: %r", key, exc_info=True)
mapping.pop(key)
else:
mapping[cls] = mapping.pop(key)
def can(obj):
"""prepare an object for pickling"""
import_needed = False
for cls,canner in can_map.iteritems():
if isinstance(cls, basestring):
import_needed = True
break
elif isinstance(obj, cls):
return canner(obj)
if import_needed:
# perform can_map imports, then try again
# this will usually only happen once
_import_mapping(can_map, _original_can_map)
return can(obj)
return obj
def can_dict(obj):
"""can the *values* of a dict"""
if isinstance(obj, dict):
newobj = {}
for k, v in obj.iteritems():
newobj[k] = can(v)
return newobj
else:
return obj
def can_sequence(obj):
"""can the elements of a sequence"""
if isinstance(obj, (list, tuple)):
t = type(obj)
return t([can(i) for i in obj])
else:
return obj
def uncan(obj, g=None):
"""invert canning"""
import_needed = False
for cls,uncanner in uncan_map.iteritems():
if isinstance(cls, basestring):
import_needed = True
break
elif isinstance(obj, cls):
return uncanner(obj, g)
if import_needed:
# perform uncan_map imports, then try again
# this will usually only happen once
_import_mapping(uncan_map, _original_uncan_map)
return uncan(obj, g)
return obj
def uncan_dict(obj, g=None):
if isinstance(obj, dict):
newobj = {}
for k, v in obj.iteritems():
newobj[k] = uncan(v,g)
return newobj
else:
return obj
def uncan_sequence(obj, g=None):
if isinstance(obj, (list, tuple)):
t = type(obj)
return t([uncan(i,g) for i in obj])
else:
return obj
#-------------------------------------------------------------------------------
# API dictionaries
#-------------------------------------------------------------------------------
# These dicts can be extended for custom serialization of new objects
can_map = {
'IPython.parallel.dependent' : lambda obj: CannedObject(obj, keys=('f','df')),
'numpy.ndarray' : CannedArray,
FunctionType : CannedFunction,
bytes : CannedBytes,
buffer : CannedBuffer,
}
uncan_map = {
CannedObject : lambda obj, g: obj.get_object(g),
}
# for use in _import_mapping:
_original_can_map = can_map.copy()
_original_uncan_map = uncan_map.copy()