For various purposes we traverse the computation done by a node tree (e.g. for
gizmos and socket usage infeferencing). For that we generally have to keep track
of the compute context we're in at any given time. During the traversal, it's
common to enter and exist the same compute contexts multiple times. Currently,
we'd always build a new compute context when that happens. That happens even
though the old one is generally still around, because other data may reference
it. This patch implements a `ComputeContextHash` type that avoids rebuilding the
same compute contexts over and over again.
I'm considering to also replace the usage of `ComputeContextBuilder` with this
cache somehow, but will see how that works out.
The reason I'm working on this now is that I have to traverse the node tree a
bit again to find where closures might be evaluated. I wanted to be able to
cache the compute contexts for a while already.
Pull Request: https://projects.blender.org/blender/blender/pulls/137360
aab2b6004b