angr.utils.cowdict

angr.utils.cowdict.merge_candidate_keys(a, b)

Return the keys that may differ between two COW chain maps which (typically) descend from a common ancestor and therefore share a common suffix of layer objects.

A key whose binding lives entirely in the shared suffix – an identical maps entry (by identity) that is not shadowed by a deletion in either map – resolves to the same value in both maps, so unioning them is always a no-op and the key is omitted. The result is the union of the keys held in each map’s non-shared “head” layers, plus the keys either map has logically deleted: a deleted key may still be bound in the other map’s shared suffix and therefore needs to be resurrected by a merge.

Return type:

set

Parameters:
class angr.utils.cowdict.ChainMapCOW

Bases: ChainMap, Generic[K, V]

Implements a copy-on-write version of ChainMap that supports auto-collapsing.

Tracks logically deleted keys via a _deleted set so that pop() and del work correctly even when keys live in parent maps.

Performance note: We deliberately re-implement the ChainMap walk for better performance. ChainMap.__getitem__ raises a KeyError for every layer that misses, and ChainMap.get walks the whole chain twice (__contains__ and __getitem__). We avoid both by inlining if key in mapping.

We may revisit the implementation in the future when the performance of ChainMap improves.

maps
dirty
collapse_threshold
clean()
Return type:

ChainMapCOW[K, V]

class angr.utils.cowdict.DefaultChainMapCOW

Bases: ChainMapCOW, Generic[K, V]

Implements a copy-on-write version of ChainMap with default values that supports auto-collapsing.

default_factory
clean()
Return type:

DefaultChainMapCOW[K, V]