102 lines
3.2 KiB
Python
102 lines
3.2 KiB
Python
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"""Find all objects reachable from a root object."""
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from __future__ import annotations
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import types
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import weakref
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from collections.abc import Iterable
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from typing import Final, Iterator, Mapping
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method_descriptor_type: Final = type(object.__dir__)
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method_wrapper_type: Final = type(object().__ne__)
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wrapper_descriptor_type: Final = type(object.__ne__)
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FUNCTION_TYPES: Final = (
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types.BuiltinFunctionType,
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types.FunctionType,
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types.MethodType,
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method_descriptor_type,
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wrapper_descriptor_type,
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method_wrapper_type,
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)
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ATTR_BLACKLIST: Final = {"__doc__", "__name__", "__class__", "__dict__"}
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# Instances of these types can't have references to other objects
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ATOMIC_TYPE_BLACKLIST: Final = {bool, int, float, str, type(None), object}
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# Don't look at most attributes of these types
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COLLECTION_TYPE_BLACKLIST: Final = {list, set, dict, tuple}
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# Don't return these objects
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TYPE_BLACKLIST: Final = {weakref.ReferenceType}
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def isproperty(o: object, attr: str) -> bool:
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return isinstance(getattr(type(o), attr, None), property)
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def get_edge_candidates(o: object) -> Iterator[tuple[object, object]]:
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# use getattr because mypyc expects dict, not mappingproxy
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if "__getattribute__" in getattr(type(o), "__dict__"): # noqa: B009
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return
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if type(o) not in COLLECTION_TYPE_BLACKLIST:
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for attr in dir(o):
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try:
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if attr not in ATTR_BLACKLIST and hasattr(o, attr) and not isproperty(o, attr):
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e = getattr(o, attr)
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if type(e) not in ATOMIC_TYPE_BLACKLIST:
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yield attr, e
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except AssertionError:
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pass
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if isinstance(o, Mapping):
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yield from o.items()
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elif isinstance(o, Iterable) and not isinstance(o, str):
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for i, e in enumerate(o):
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yield i, e
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def get_edges(o: object) -> Iterator[tuple[object, object]]:
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for s, e in get_edge_candidates(o):
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if isinstance(e, FUNCTION_TYPES):
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# We don't want to collect methods, but do want to collect values
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# in closures and self pointers to other objects
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if hasattr(e, "__closure__"):
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yield (s, "__closure__"), e.__closure__
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if hasattr(e, "__self__"):
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se = e.__self__
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if se is not o and se is not type(o) and hasattr(s, "__self__"):
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yield s.__self__, se
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else:
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if type(e) not in TYPE_BLACKLIST:
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yield s, e
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def get_reachable_graph(root: object) -> tuple[dict[int, object], dict[int, tuple[int, object]]]:
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parents = {}
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seen = {id(root): root}
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worklist = [root]
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while worklist:
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o = worklist.pop()
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for s, e in get_edges(o):
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if id(e) in seen:
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continue
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parents[id(e)] = (id(o), s)
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seen[id(e)] = e
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worklist.append(e)
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return seen, parents
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def get_path(
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o: object, seen: dict[int, object], parents: dict[int, tuple[int, object]]
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) -> list[tuple[object, object]]:
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path = []
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while id(o) in parents:
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pid, attr = parents[id(o)]
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o = seen[pid]
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path.append((attr, o))
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path.reverse()
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return path
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