mirror of https://github.com/home-assistant/core
69 lines
1.8 KiB
Python
69 lines
1.8 KiB
Python
"""Merging of policies."""
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from __future__ import annotations
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from typing import cast
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from .types import CategoryType, PolicyType
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def merge_policies(policies: list[PolicyType]) -> PolicyType:
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"""Merge policies."""
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new_policy: dict[str, CategoryType] = {}
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seen: set[str] = set()
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for policy in policies:
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for category in policy:
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if category in seen:
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continue
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seen.add(category)
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new_policy[category] = _merge_policies(
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[policy.get(category) for policy in policies]
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)
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cast(PolicyType, new_policy)
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return new_policy
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def _merge_policies(sources: list[CategoryType]) -> CategoryType:
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"""Merge a policy."""
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# When merging policies, the most permissive wins.
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# This means we order it like this:
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# True > Dict > None
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#
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# True: allow everything
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# Dict: specify more granular permissions
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# None: no opinion
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#
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# If there are multiple sources with a dict as policy, we recursively
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# merge each key in the source.
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policy: CategoryType = None
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seen: set[str] = set()
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for source in sources:
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if source is None:
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continue
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# A source that's True will always win. Shortcut return.
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if source is True:
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return True
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assert isinstance(source, dict)
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if policy is None:
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policy = cast(CategoryType, {})
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assert isinstance(policy, dict)
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for key in source:
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if key in seen:
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continue
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seen.add(key)
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key_sources = []
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for src in sources:
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if isinstance(src, dict):
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key_sources.append(src.get(key))
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policy[key] = _merge_policies(key_sources)
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return policy
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