122 lines
3.3 KiB
Python
122 lines
3.3 KiB
Python
"""Find all objects reachable from a root object."""
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from collections.abc import Iterable
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import weakref
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import types
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from typing import List, Dict, Iterator, Tuple, Mapping
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from typing_extensions import Final
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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 = {
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'__doc__',
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'__name__',
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'__class__',
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'__dict__',
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}
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# Instances of these types can't have references to other objects
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ATOMIC_TYPE_BLACKLIST: Final = {
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bool,
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int,
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float,
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str,
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type(None),
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object,
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}
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# Don't look at most attributes of these types
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COLLECTION_TYPE_BLACKLIST: Final = {
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list,
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set,
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dict,
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tuple,
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}
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# Don't return these objects
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TYPE_BLACKLIST: Final = {
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weakref.ReferenceType,
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}
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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
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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 not type(e) 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__ # type: ignore
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if hasattr(e, '__self__'):
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se = e.__self__ # type: ignore
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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 # type: ignore
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else:
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if not type(e) in TYPE_BLACKLIST:
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yield s, e
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def get_reachable_graph(root: object) -> Tuple[Dict[int, object],
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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(o: object,
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seen: Dict[int, object],
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parents: Dict[int, Tuple[int, object]]) -> 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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