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# Licensed under the Apache License, Version 2.0 (the "License");
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import hashlib
import inspect
import json
import types
from typing import Any

import torch
from torch._inductor.custom_graph_pass import CustomGraphPass

from magi_compiler.utils import compute_hash


class InductorPass(CustomGraphPass):
    """
    A custom graph pass that uses a hash of its source as the UUID.
    This is defined as a convenience and should work in most cases.
    """

    def uuid(self) -> Any:
        """
        Provide a unique identifier for the pass, used in Inductor code cache.
        This should depend on the pass implementation, so that changes to the
        pass result in recompilation.
        By default, the object source is hashed.
        """
        return InductorPass.hash_source(self)

    @staticmethod
    def hash_source(*srcs: str | Any):
        """
        Utility method to hash the sources of functions or objects.
        :param srcs: strings or objects to add to the hash.
        Objects and functions have their source inspected.
        :return:
        """
        hasher = hashlib.sha256()
        for src in srcs:
            if isinstance(src, str):
                src_str = src
            elif isinstance(src, (types.FunctionType, type)):
                src_str = inspect.getsource(src)
            else:
                # object instance
                src_str = inspect.getsource(src.__class__)
            hasher.update(src_str.encode("utf-8"))
        return hasher.hexdigest()

    @staticmethod
    def hash_dict(dict_: dict[Any, Any]):
        """
        Utility method to hash a dictionary, can alternatively be used for uuid.
        :return: A sha256 hash of the json rep of the dictionary.
        """
        encoded = json.dumps(dict_, sort_keys=True).encode("utf-8")
        return compute_hash(encoded)

    def is_applicable(self, graph: torch.fx.Graph, shape: int | None = None) -> bool:
        return True