632 lines
18 KiB
Python
632 lines
18 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 copyreg as copy_reg
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import re
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import types
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from twisted.persisted import crefutil
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from twisted.python import log, reflect
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from twisted.python.compat import _constructMethod
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# tokenize from py3.11 is vendored to work around https://github.com/python/cpython/issues/105238
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# on 3.12
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from ._tokenize import generate_tokens as tokenize
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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 (
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isinstance(inst, Ref)
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or isinstance(inst, Instance)
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or isinstance(inst, Deref)
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):
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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{})".format(
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self.name,
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self.klass,
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prettify(self.instance),
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)
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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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bool,
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bytes,
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str,
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int,
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float,
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complex,
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type(None),
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slice,
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type(Ellipsis),
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]
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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, str):
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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, dict):
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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 f"Instance({self.klass!r}, {dictToKW(stateDict)})"
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except NonFormattableDict:
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return f"Instance({self.klass!r}, {prettify(stateDict)})"
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return f"Instance({self.klass!r}, {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(f"Error setting id {num}, I already have {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(f"Error setting obj {obj}, I already have {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(
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"Don't try to display me before setting an object on me!"
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)
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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 f"Copyreg({self.loadfunc!r}, {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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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 = list(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, str):
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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(f"\n\0{k}={prettify(v)},")
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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 dict:
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out = ["{"]
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for k, v in obj.items():
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out.append(f"\n\0{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 list:
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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 tuple:
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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(f"Unsupported type {t} when trying to prettify {obj}.")
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def indentify(s):
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out = []
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stack = []
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l = ["", s]
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for (
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tokenType,
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tokenString,
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(startRow, startColumn),
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(endRow, endColumn),
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logicalLine,
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) in tokenize(l.pop):
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if tokenString in ["[", "(", "{"]:
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stack.append(tokenString)
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elif tokenString in ["]", ")", "}"]:
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stack.pop()
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if tokenString == "\0":
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out.append(" " * len(stack))
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else:
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out.append(tokenString)
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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 = {
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"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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source = stringOrFile.read()
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else:
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source = stringOrFile
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code = compile(source, "<source>", "exec")
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eval(code, ns, 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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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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listResult = [None]
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result.addDependant(listResult, 1)
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else:
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listResult = [result]
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self.afterUnjelly.append((callable, listResult))
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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 in _SIMPLE_BUILTINS:
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return ao
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elif t is list:
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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 tuple:
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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 dict:
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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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# 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 _constructMethod(im_class, im_name, im_self)
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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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inst = klass.__new__(klass)
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if hasattr(klass, "__setstate__"):
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self.callAfter(inst.__setstate__, state)
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elif isinstance(state, dict):
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inst.__dict__ = state
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else:
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inst.__dict__ = state.__getstate__()
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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(
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"Multiple references with the same ID: %s, %s, %s!"
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% (ref, refkey, ao)
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)
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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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)
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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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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 BaseException:
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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).encode("utf-8"))
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else:
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return getSource(aot)
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def _classOfMethod(methodObject):
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"""
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Get the associated class of the given method object.
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@param methodObject: a bound method
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@type methodObject: L{types.MethodType}
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@return: a class
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@rtype: L{type}
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"""
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return methodObject.__self__.__class__
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def _funcOfMethod(methodObject):
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"""
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Get the associated function of the given method object.
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@param methodObject: a bound method
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@type methodObject: L{types.MethodType}
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@return: the function implementing C{methodObject}
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@rtype: L{types.FunctionType}
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"""
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return methodObject.__func__
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def _selfOfMethod(methodObject):
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"""
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Get the object that a bound method is bound to.
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@param methodObject: a bound method
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@type methodObject: L{types.MethodType}
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@return: the C{self} passed to C{methodObject}
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@rtype: L{object}
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"""
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return methodObject.__self__
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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 issubclass(objType, 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(
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_funcOfMethod(obj).__name__,
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reflect.qual(_classOfMethod(obj)),
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self.jellyToAO(_selfOfMethod(obj)),
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)
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elif issubclass(objType, types.ModuleType):
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retval = Module(obj.__name__)
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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
|
|
# object if it has a Reference explicitly attached.
|
|
|
|
if id(obj) in self.prepared:
|
|
oldRef = self.prepared[id(obj)]
|
|
if oldRef.refnum:
|
|
# it's been referenced already
|
|
key = oldRef.refnum
|
|
else:
|
|
# it hasn't been referenced yet
|
|
self._ref_id = self._ref_id + 1
|
|
key = self._ref_id
|
|
oldRef.setRef(key)
|
|
return Deref(key)
|
|
|
|
retval = Ref()
|
|
|
|
def _stateFrom(state):
|
|
retval.setObj(
|
|
Instance(reflect.qual(obj.__class__), self.jellyToAO(state))
|
|
)
|
|
|
|
self.prepareForRef(retval, obj)
|
|
|
|
if objType is list:
|
|
retval.setObj([self.jellyToAO(o) for o in obj]) # hah!
|
|
|
|
elif objType is tuple:
|
|
retval.setObj(tuple(map(self.jellyToAO, obj)))
|
|
|
|
elif objType is dict:
|
|
d = {}
|
|
for k, v in obj.items():
|
|
d[self.jellyToAO(k)] = self.jellyToAO(v)
|
|
retval.setObj(d)
|
|
|
|
elif objType in copy_reg.dispatch_table:
|
|
unpickleFunc, state = copy_reg.dispatch_table[objType](obj)
|
|
|
|
retval.setObj(
|
|
Copyreg(reflect.fullFuncName(unpickleFunc), self.jellyToAO(state))
|
|
)
|
|
|
|
elif hasattr(obj, "__getstate__"):
|
|
_stateFrom(obj.__getstate__())
|
|
elif hasattr(obj, "__dict__"):
|
|
_stateFrom(obj.__dict__)
|
|
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 BaseException:
|
|
log.msg("Error jellying object! Stacktrace follows::")
|
|
log.msg("\n".join(self.stack))
|
|
raise
|