157 lines
4.8 KiB
Nim
157 lines
4.8 KiB
Nim
# nimbus-eth1
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# Copyright (c) 2021 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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## Aristo DB -- Patricia Trie delete funcionality
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## ==============================================
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##
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## Deleate by `Hike` type chain of vertices.
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{.push raises: [].}
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import
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std/[sets, tables],
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chronicles,
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eth/[common, trie/nibbles],
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stew/results,
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"."/[aristo_desc, aristo_get, aristo_hike, aristo_path, aristo_vid]
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logScope:
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topics = "aristo-delete"
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# ------------------------------------------------------------------------------
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# Private functions
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# ------------------------------------------------------------------------------
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proc branchStillNeeded(vtx: VertexRef): bool =
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for n in 0 .. 15:
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if vtx.bVid[n].isValid:
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return true
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proc clearKey(
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db: AristoDb; # Database, top layer
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vid: VertexID; # Vertex IDs to clear
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) =
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let lbl = db.top.kMap.getOrVoid vid
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if lbl.isValid:
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db.top.kMap.del vid
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db.top.pAmk.del lbl
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elif db.getKeyBackend(vid).isOK:
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# Register for deleting on backend
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db.top.kMap[vid] = VOID_HASH_LABEL
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db.top.pAmk.del lbl
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proc doneWith(
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db: AristoDb; # Database, top layer
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vid: VertexID; # Vertex IDs to clear
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) =
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# Remove entry
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db.vidDispose vid # Will be propagated to backend
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db.top.sTab.del vid
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db.clearKey vid
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proc deleteImpl(
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hike: Hike; # Fully expanded path
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lty: LeafTie; # `Patricia Trie` path root-to-leaf
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db: AristoDb; # Database, top layer
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): Result[void,(VertexID,AristoError)] =
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## Implementation of *delete* functionality.
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if hike.error != AristoError(0):
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if 0 < hike.legs.len:
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return err((hike.legs[^1].wp.vid,hike.error))
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return err((VertexID(0),hike.error))
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# doAssert 0 < hike.legs.len and hike.tail.len == 0 # as assured by `hikeUp()`
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var lf: VidVtxPair
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block:
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var inx = hike.legs.len - 1
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# Remove leaf entry on the top
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lf = hike.legs[inx].wp
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if lf.vtx.vType != Leaf:
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return err((lf.vid,DelLeafExpexted))
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if lf.vid in db.top.pPrf:
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return err((lf.vid, DelLeafLocked))
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db.doneWith(lf.vid)
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inx.dec
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while 0 <= inx:
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# Unlink child vertex
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let br = hike.legs[inx].wp
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if br.vtx.vType != Branch:
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return err((br.vid,DelBranchExpexted))
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if br.vid in db.top.pPrf:
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return err((br.vid, DelBranchLocked))
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br.vtx.bVid[hike.legs[inx].nibble] = VertexID(0)
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db.top.sTab[br.vid] = br.vtx
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if br.vtx.branchStillNeeded:
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# Clear all keys up to the toot key
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db.clearKey(br.vid)
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while 0 < inx:
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inx.dec
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db.clearKey(hike.legs[inx].wp.vid)
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break
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# Remove this `Branch` entry
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db.doneWith(br.vid)
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inx.dec
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if inx < 0:
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break
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# There might be an optional `Extension` to remove
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let ext = hike.legs[inx].wp
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if ext.vtx.vType == Extension:
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if br.vid in db.top.pPrf:
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return err((ext.vid, DelExtLocked))
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db.doneWith(ext.vid)
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inx.dec
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# Delete leaf entry
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let rc = db.getVtxBackend lf.vid
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if rc.isErr and rc.error == GetVtxNotFound:
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# No need to keep it any longer
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db.top.lTab.del lty
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else:
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# To be recorded on change history
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db.top.lTab[lty] = VertexID(0)
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ok()
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# ------------------------------------------------------------------------------
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# Public functions
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# ------------------------------------------------------------------------------
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proc delete*(
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hike: Hike; # Fully expanded chain of vertices
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db: AristoDb; # Database, top layer
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): Result[void,(VertexID,AristoError)] =
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## Delete argument `hike` chain of vertices from the database
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# Need path in order to remove it from `lTab[]`
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let lky = block:
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let rc = hike.to(NibblesSeq).pathToTag()
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if rc.isErr:
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return err((VertexID(0),DelPathTagError))
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LeafTie(root: hike.root, path: rc.value)
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hike.deleteImpl(lky, db)
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proc delete*(
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lty: LeafTie; # `Patricia Trie` path root-to-leaf
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db: AristoDb; # Database, top layer
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): Result[void,(VertexID,AristoError)] =
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## Variant of `delete()`
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lty.hikeUp(db).deleteImpl(lty, db)
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# ------------------------------------------------------------------------------
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# End
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# ------------------------------------------------------------------------------
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