63 lines
1.9 KiB
Python
63 lines
1.9 KiB
Python
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"""Canonical serialization and stable SHA-256 helpers."""
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from __future__ import annotations
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import dataclasses
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import hashlib
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import json
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from pathlib import Path
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from typing import Any, Mapping
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import numpy as np
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def to_jsonable(value: Any) -> Any:
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"""Convert supported scientific-Python values to strict JSON values."""
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if dataclasses.is_dataclass(value):
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return to_jsonable(dataclasses.asdict(value))
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if isinstance(value, Path):
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return str(value)
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if isinstance(value, np.ndarray):
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return to_jsonable(value.tolist())
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if isinstance(value, np.generic):
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return to_jsonable(value.item())
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if isinstance(value, Mapping):
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return {str(key): to_jsonable(item) for key, item in value.items()}
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if isinstance(value, (tuple, list)):
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return [to_jsonable(item) for item in value]
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if isinstance(value, (str, int, float, bool)) or value is None:
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return value
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raise TypeError(f"Unsupported value for canonical JSON: {type(value).__name__}")
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def canonical_json_bytes(value: Any) -> bytes:
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"""Return deterministic UTF-8 JSON bytes, rejecting NaN and infinity."""
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return json.dumps(
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to_jsonable(value),
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sort_keys=True,
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separators=(",", ":"),
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ensure_ascii=False,
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allow_nan=False,
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).encode("utf-8")
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def stable_hash(value: Any, *, prefix: str = "") -> str:
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"""Hash a value using canonical JSON and an optional domain prefix."""
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digest = hashlib.sha256()
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if prefix:
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digest.update(prefix.encode("utf-8"))
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digest.update(b"\0")
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digest.update(canonical_json_bytes(value))
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return digest.hexdigest()
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def file_sha256(path: Path) -> str:
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digest = hashlib.sha256()
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with path.open("rb") as stream:
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while True:
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block = stream.read(1024 * 1024)
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if not block:
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break
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digest.update(block)
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return digest.hexdigest()
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