560 lines
17 KiB
Python
560 lines
17 KiB
Python
# -*- test-case-name: twisted.test.test_persisted -*-
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# Copyright (c) Twisted Matrix Laboratories.
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# See LICENSE for details.
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"""
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AOT: Abstract Object Trees
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The source-code-marshallin'est abstract-object-serializin'est persister
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this side of Marmalade!
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"""
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import types, copy_reg, tokenize, re
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from twisted.python import reflect, log
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from twisted.persisted import crefutil
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###########################
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# Abstract Object Classes #
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###########################
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#"\0" in a getSource means "insert variable-width indention here".
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#see `indentify'.
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class Named:
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def __init__(self, name):
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self.name = name
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class Class(Named):
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def getSource(self):
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return "Class(%r)" % self.name
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class Function(Named):
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def getSource(self):
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return "Function(%r)" % self.name
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class Module(Named):
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def getSource(self):
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return "Module(%r)" % self.name
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class InstanceMethod:
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def __init__(self, name, klass, inst):
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if not (isinstance(inst, Ref) or isinstance(inst, Instance) or isinstance(inst, Deref)):
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raise TypeError("%s isn't an Instance, Ref, or Deref!" % inst)
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self.name = name
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self.klass = klass
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self.instance = inst
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def getSource(self):
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return "InstanceMethod(%r, %r, \n\0%s)" % (self.name, self.klass, prettify(self.instance))
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class _NoStateObj:
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pass
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NoStateObj = _NoStateObj()
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_SIMPLE_BUILTINS = [
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types.StringType, types.UnicodeType, types.IntType, types.FloatType,
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types.ComplexType, types.LongType, types.NoneType, types.SliceType,
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types.EllipsisType]
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try:
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_SIMPLE_BUILTINS.append(types.BooleanType)
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except AttributeError:
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pass
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class Instance:
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def __init__(self, className, __stateObj__=NoStateObj, **state):
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if not isinstance(className, types.StringType):
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raise TypeError("%s isn't a string!" % className)
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self.klass = className
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if __stateObj__ is not NoStateObj:
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self.state = __stateObj__
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self.stateIsDict = 0
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else:
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self.state = state
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self.stateIsDict = 1
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def getSource(self):
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#XXX make state be foo=bar instead of a dict.
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if self.stateIsDict:
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stateDict = self.state
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elif isinstance(self.state, Ref) and isinstance(self.state.obj, types.DictType):
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stateDict = self.state.obj
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else:
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stateDict = None
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if stateDict is not None:
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try:
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return "Instance(%r, %s)" % (self.klass, dictToKW(stateDict))
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except NonFormattableDict:
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return "Instance(%r, %s)" % (self.klass, prettify(stateDict))
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return "Instance(%r, %s)" % (self.klass, prettify(self.state))
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class Ref:
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def __init__(self, *args):
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#blargh, lame.
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if len(args) == 2:
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self.refnum = args[0]
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self.obj = args[1]
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elif not args:
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self.refnum = None
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self.obj = None
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def setRef(self, num):
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if self.refnum:
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raise ValueError("Error setting id %s, I already have %s" % (num, self.refnum))
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self.refnum = num
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def setObj(self, obj):
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if self.obj:
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raise ValueError("Error setting obj %s, I already have %s" % (obj, self.obj))
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self.obj = obj
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def getSource(self):
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if self.obj is None:
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raise RuntimeError("Don't try to display me before setting an object on me!")
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if self.refnum:
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return "Ref(%d, \n\0%s)" % (self.refnum, prettify(self.obj))
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return prettify(self.obj)
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class Deref:
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def __init__(self, num):
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self.refnum = num
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def getSource(self):
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return "Deref(%d)" % self.refnum
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__repr__ = getSource
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class Copyreg:
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def __init__(self, loadfunc, state):
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self.loadfunc = loadfunc
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self.state = state
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def getSource(self):
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return "Copyreg(%r, %s)" % (self.loadfunc, prettify(self.state))
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###############
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# Marshalling #
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###############
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def getSource(ao):
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"""Pass me an AO, I'll return a nicely-formatted source representation."""
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return indentify("app = " + prettify(ao))
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class NonFormattableDict(Exception):
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"""A dictionary was not formattable.
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"""
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r = re.compile('[a-zA-Z_][a-zA-Z0-9_]*$')
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def dictToKW(d):
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out = []
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items = d.items()
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items.sort()
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for k,v in items:
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if not isinstance(k, types.StringType):
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raise NonFormattableDict("%r ain't a string" % k)
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if not r.match(k):
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raise NonFormattableDict("%r ain't an identifier" % k)
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out.append(
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"\n\0%s=%s," % (k, prettify(v))
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)
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return ''.join(out)
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def prettify(obj):
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if hasattr(obj, 'getSource'):
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return obj.getSource()
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else:
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#basic type
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t = type(obj)
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if t in _SIMPLE_BUILTINS:
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return repr(obj)
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elif t is types.DictType:
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out = ['{']
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for k,v in obj.items():
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out.append('\n\0%s: %s,' % (prettify(k), prettify(v)))
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out.append(len(obj) and '\n\0}' or '}')
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return ''.join(out)
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elif t is types.ListType:
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out = ["["]
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for x in obj:
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out.append('\n\0%s,' % prettify(x))
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out.append(len(obj) and '\n\0]' or ']')
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return ''.join(out)
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elif t is types.TupleType:
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out = ["("]
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for x in obj:
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out.append('\n\0%s,' % prettify(x))
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out.append(len(obj) and '\n\0)' or ')')
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return ''.join(out)
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else:
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raise TypeError("Unsupported type %s when trying to prettify %s." % (t, obj))
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def indentify(s):
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out = []
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stack = []
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def eater(type, val, r, c, l, out=out, stack=stack):
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#import sys
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#sys.stdout.write(val)
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if val in ['[', '(', '{']:
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stack.append(val)
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elif val in [']', ')', '}']:
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stack.pop()
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if val == '\0':
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out.append(' '*len(stack))
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else:
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out.append(val)
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l = ['', s]
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tokenize.tokenize(l.pop, eater)
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return ''.join(out)
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###########
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# Unjelly #
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###########
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def unjellyFromAOT(aot):
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"""
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Pass me an Abstract Object Tree, and I'll unjelly it for you.
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"""
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return AOTUnjellier().unjelly(aot)
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def unjellyFromSource(stringOrFile):
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"""
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Pass me a string of code or a filename that defines an 'app' variable (in
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terms of Abstract Objects!), and I'll execute it and unjelly the resulting
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AOT for you, returning a newly unpersisted Application object!
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"""
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ns = {"Instance": Instance,
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"InstanceMethod": InstanceMethod,
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"Class": Class,
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"Function": Function,
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"Module": Module,
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"Ref": Ref,
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"Deref": Deref,
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"Copyreg": Copyreg,
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}
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if hasattr(stringOrFile, "read"):
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exec stringOrFile.read() in ns
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else:
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exec stringOrFile in ns
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if 'app' in ns:
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return unjellyFromAOT(ns['app'])
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else:
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raise ValueError("%s needs to define an 'app', it didn't!" % stringOrFile)
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class AOTUnjellier:
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"""I handle the unjellying of an Abstract Object Tree.
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See AOTUnjellier.unjellyAO
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"""
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def __init__(self):
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self.references = {}
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self.stack = []
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self.afterUnjelly = []
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##
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# unjelly helpers (copied pretty much directly from (now deleted) marmalade)
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##
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def unjellyLater(self, node):
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"""Unjelly a node, later.
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"""
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d = crefutil._Defer()
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self.unjellyInto(d, 0, node)
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return d
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def unjellyInto(self, obj, loc, ao):
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"""Utility method for unjellying one object into another.
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This automates the handling of backreferences.
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"""
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o = self.unjellyAO(ao)
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obj[loc] = o
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if isinstance(o, crefutil.NotKnown):
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o.addDependant(obj, loc)
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return o
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def callAfter(self, callable, result):
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if isinstance(result, crefutil.NotKnown):
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l = [None]
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result.addDependant(l, 1)
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else:
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l = [result]
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self.afterUnjelly.append((callable, l))
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def unjellyAttribute(self, instance, attrName, ao):
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#XXX this is unused????
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"""Utility method for unjellying into instances of attributes.
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Use this rather than unjellyAO unless you like surprising bugs!
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Alternatively, you can use unjellyInto on your instance's __dict__.
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"""
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self.unjellyInto(instance.__dict__, attrName, ao)
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def unjellyAO(self, ao):
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"""Unjelly an Abstract Object and everything it contains.
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I return the real object.
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"""
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self.stack.append(ao)
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t = type(ao)
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if t is types.InstanceType:
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#Abstract Objects
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c = ao.__class__
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if c is Module:
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return reflect.namedModule(ao.name)
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elif c in [Class, Function] or issubclass(c, type):
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return reflect.namedObject(ao.name)
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elif c is InstanceMethod:
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im_name = ao.name
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im_class = reflect.namedObject(ao.klass)
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im_self = self.unjellyAO(ao.instance)
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if im_name in im_class.__dict__:
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if im_self is None:
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return getattr(im_class, im_name)
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elif isinstance(im_self, crefutil.NotKnown):
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return crefutil._InstanceMethod(im_name, im_self, im_class)
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else:
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return types.MethodType(im_class.__dict__[im_name],
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im_self,
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im_class)
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else:
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raise TypeError("instance method changed")
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elif c is Instance:
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klass = reflect.namedObject(ao.klass)
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state = self.unjellyAO(ao.state)
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if hasattr(klass, "__setstate__"):
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inst = types.InstanceType(klass, {})
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self.callAfter(inst.__setstate__, state)
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else:
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inst = types.InstanceType(klass, state)
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return inst
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elif c is Ref:
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o = self.unjellyAO(ao.obj) #THIS IS CHANGING THE REF OMG
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refkey = ao.refnum
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ref = self.references.get(refkey)
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if ref is None:
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self.references[refkey] = o
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elif isinstance(ref, crefutil.NotKnown):
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ref.resolveDependants(o)
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self.references[refkey] = o
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elif refkey is None:
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# This happens when you're unjellying from an AOT not read from source
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pass
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else:
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raise ValueError("Multiple references with the same ID: %s, %s, %s!" % (ref, refkey, ao))
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return o
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elif c is Deref:
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num = ao.refnum
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ref = self.references.get(num)
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if ref is None:
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der = crefutil._Dereference(num)
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self.references[num] = der
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return der
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return ref
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elif c is Copyreg:
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loadfunc = reflect.namedObject(ao.loadfunc)
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d = self.unjellyLater(ao.state).addCallback(
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lambda result, _l: _l(*result), loadfunc)
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return d
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#Types
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elif t in _SIMPLE_BUILTINS:
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return ao
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elif t is types.ListType:
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l = []
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for x in ao:
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l.append(None)
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self.unjellyInto(l, len(l)-1, x)
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return l
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elif t is types.TupleType:
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l = []
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tuple_ = tuple
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for x in ao:
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l.append(None)
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if isinstance(self.unjellyInto(l, len(l)-1, x), crefutil.NotKnown):
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tuple_ = crefutil._Tuple
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return tuple_(l)
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elif t is types.DictType:
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d = {}
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for k,v in ao.items():
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kvd = crefutil._DictKeyAndValue(d)
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self.unjellyInto(kvd, 0, k)
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self.unjellyInto(kvd, 1, v)
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return d
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else:
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raise TypeError("Unsupported AOT type: %s" % t)
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del self.stack[-1]
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def unjelly(self, ao):
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try:
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l = [None]
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self.unjellyInto(l, 0, ao)
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for func, v in self.afterUnjelly:
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func(v[0])
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return l[0]
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except:
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log.msg("Error jellying object! Stacktrace follows::")
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log.msg("\n".join(map(repr, self.stack)))
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raise
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#########
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# Jelly #
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#########
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def jellyToAOT(obj):
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"""Convert an object to an Abstract Object Tree."""
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return AOTJellier().jelly(obj)
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def jellyToSource(obj, file=None):
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"""
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Pass me an object and, optionally, a file object.
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I'll convert the object to an AOT either return it (if no file was
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specified) or write it to the file.
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"""
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aot = jellyToAOT(obj)
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if file:
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file.write(getSource(aot))
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else:
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return getSource(aot)
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class AOTJellier:
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def __init__(self):
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# dict of {id(obj): (obj, node)}
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self.prepared = {}
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self._ref_id = 0
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self.stack = []
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def prepareForRef(self, aoref, object):
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"""I prepare an object for later referencing, by storing its id()
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and its _AORef in a cache."""
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self.prepared[id(object)] = aoref
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def jellyToAO(self, obj):
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"""I turn an object into an AOT and return it."""
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objType = type(obj)
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self.stack.append(repr(obj))
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#immutable: We don't care if these have multiple refs!
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if objType in _SIMPLE_BUILTINS:
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retval = obj
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elif objType is types.MethodType:
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# TODO: make methods 'prefer' not to jelly the object internally,
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# so that the object will show up where it's referenced first NOT
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# by a method.
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retval = InstanceMethod(obj.im_func.__name__, reflect.qual(obj.im_class),
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self.jellyToAO(obj.im_self))
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elif objType is types.ModuleType:
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retval = Module(obj.__name__)
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elif objType is types.ClassType:
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retval = Class(reflect.qual(obj))
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elif issubclass(objType, type):
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retval = Class(reflect.qual(obj))
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elif objType is types.FunctionType:
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retval = Function(reflect.fullFuncName(obj))
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else: #mutable! gotta watch for refs.
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#Marmalade had the nicety of being able to just stick a 'reference' attribute
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#on any Node object that was referenced, but in AOT, the referenced object
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#is *inside* of a Ref call (Ref(num, obj) instead of
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#<objtype ... reference="1">). The problem is, especially for built-in types,
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#I can't just assign some attribute to them to give them a refnum. So, I have
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#to "wrap" a Ref(..) around them later -- that's why I put *everything* that's
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#mutable inside one. The Ref() class will only print the "Ref(..)" around an
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#object if it has a Reference explicitly attached.
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if id(obj) in self.prepared:
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oldRef = self.prepared[id(obj)]
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if oldRef.refnum:
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# it's been referenced already
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key = oldRef.refnum
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else:
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# it hasn't been referenced yet
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self._ref_id = self._ref_id + 1
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key = self._ref_id
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oldRef.setRef(key)
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return Deref(key)
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retval = Ref()
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self.prepareForRef(retval, obj)
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if objType is types.ListType:
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retval.setObj(map(self.jellyToAO, obj)) #hah!
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elif objType is types.TupleType:
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retval.setObj(tuple(map(self.jellyToAO, obj)))
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elif objType is types.DictionaryType:
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d = {}
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for k,v in obj.items():
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d[self.jellyToAO(k)] = self.jellyToAO(v)
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retval.setObj(d)
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elif objType is types.InstanceType:
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if hasattr(obj, "__getstate__"):
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state = self.jellyToAO(obj.__getstate__())
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else:
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state = self.jellyToAO(obj.__dict__)
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retval.setObj(Instance(reflect.qual(obj.__class__), state))
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elif objType in copy_reg.dispatch_table:
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unpickleFunc, state = copy_reg.dispatch_table[objType](obj)
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retval.setObj(Copyreg( reflect.fullFuncName(unpickleFunc),
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self.jellyToAO(state)))
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else:
|
|
raise TypeError("Unsupported type: %s" % objType.__name__)
|
|
|
|
del self.stack[-1]
|
|
return retval
|
|
|
|
def jelly(self, obj):
|
|
try:
|
|
ao = self.jellyToAO(obj)
|
|
return ao
|
|
except:
|
|
log.msg("Error jellying object! Stacktrace follows::")
|
|
log.msg('\n'.join(self.stack))
|
|
raise
|