86 lines
3.0 KiB
Nim
86 lines
3.0 KiB
Nim
# nimbus-eth1
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# Copyright (c) 2023-2024 Status Research & Development GmbH
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# Licensed under either of
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# * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or
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# http://www.apache.org/licenses/LICENSE-2.0)
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# * MIT license ([LICENSE-MIT](LICENSE-MIT) or
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# http://opensource.org/licenses/MIT)
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# at your option. This file may not be copied, modified, or distributed
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# except according to those terms.
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import
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std/tables,
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eth/common,
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".."/[aristo_desc, aristo_layers]
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# ------------------------------------------------------------------------------
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# Public functions
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# ------------------------------------------------------------------------------
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proc deltaMerge*(
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upper: LayerRef; # Think of `top`, `nil` is ok
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modUpperOk: bool; # May re-use/modify `upper`
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lower: LayerRef; # Think of `balancer`, `nil` is ok
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modLowerOk: bool; # May re-use/modify `lower`
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): LayerRef =
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## Merge argument `upper` into the `lower` filter instance.
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##
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## Note that the namimg `upper` and `lower` indicate that the filters are
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## stacked and the database access is `upper -> lower -> backend`.
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##
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if lower.isNil:
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# Degenerate case: `upper` is void
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result = upper
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elif upper.isNil:
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# Degenerate case: `lower` is void
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result = lower
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elif modLowerOk:
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# Can modify `lower` which is the prefered action mode but applies only
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# in cases where the `lower` argument is not shared.
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lower.vTop = upper.vTop
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layersMergeOnto(upper, lower[])
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result = lower
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elif not modUpperOk:
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# Cannot modify any argument layers.
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result = LayerRef(
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sTab: lower.sTab, # shallow copy (entries will not be modified)
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kMap: lower.kMap,
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delTree: lower.delTree,
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accLeaves: lower.accLeaves,
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stoLeaves: lower.stoLeaves,
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vTop: upper.vTop)
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layersMergeOnto(upper, result[])
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else:
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# Otherwise avoid copying some tables by modifying `upper`. This is not
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# completely free as the merge direction changes to merging the `lower`
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# layer up into the higher prioritised `upper` layer (note that the `lower`
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# argument filter is read-only.) Here again, the `upper` argument must not
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# be a shared layer/filter.
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for (rvid,vtx) in lower.sTab.pairs:
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if not upper.sTab.hasKey(rvid):
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upper.sTab[rvid] = vtx
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for (rvid,key) in lower.kMap.pairs:
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if not upper.kMap.hasKey(rvid):
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upper.kMap[rvid] = key
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for rvid in lower.delTree:
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upper.delTree.add rvid
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for (accPath,leafVtx) in lower.accLeaves.pairs:
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if not upper.accLeaves.hasKey(accPath):
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upper.accLeaves[accPath] = leafVtx
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for (mixPath,leafVtx) in lower.stoLeaves.pairs:
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if not upper.stoLeaves.hasKey(mixPath):
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upper.stoLeaves[mixPath] = leafVtx
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result = upper
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# ------------------------------------------------------------------------------
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# End
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# ------------------------------------------------------------------------------
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