480 lines
16 KiB
Nim
480 lines
16 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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## Aristo DB -- Patricia Trie delete funcionality
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## ==============================================
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##
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## Delete by `Hike` type chain of vertices.
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{.push raises: [].}
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import
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std/typetraits,
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eth/common,
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results,
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"."/[aristo_desc, aristo_fetch, aristo_get, aristo_hike, aristo_layers,
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aristo_utils, aristo_vid]
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# ------------------------------------------------------------------------------
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# Private heplers
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# ------------------------------------------------------------------------------
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proc branchStillNeeded(vtx: VertexRef): Result[int,void] =
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## Returns the nibble if there is only one reference left.
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var nibble = -1
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for n in 0 .. 15:
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if vtx.bVid[n].isValid:
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if 0 <= nibble:
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return ok(-1)
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nibble = n
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if 0 <= nibble:
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return ok(nibble)
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# Oops, degenerated branch node
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err()
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# -----------
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proc disposeOfVtx(
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db: AristoDbRef; # Database, top layer
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rvid: RootedVertexID; # Vertex ID to clear
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) =
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# Remove entry
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db.layersResVtx(rvid)
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db.layersResKey(rvid)
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db.vidDispose rvid.vid # Recycle ID
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# ------------------------------------------------------------------------------
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# Private functions
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# ------------------------------------------------------------------------------
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proc collapseBranch(
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db: AristoDbRef; # Database, top layer
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hike: Hike; # Fully expanded path
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nibble: byte; # Applicable link for `Branch` vertex
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): Result[void,(VertexID,AristoError)] =
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## Convert/merge vertices:
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## ::
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## current | becomes | condition
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## | |
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## ^3 ^2 | ^3 ^2 |
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## -------------------+---------------------+------------------
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## Branch <br> Branch | Branch <ext> Branch | 2 < legs.len (1)
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## Ext <br> Branch | <ext> Branch | 2 < legs.len (2)
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## <br> Branch | <ext> Branch | legs.len == 2 (3)
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##
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## Depending on whether the parent `par` is an extension, merge `br` into
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## `par`. Otherwise replace `br` by an extension.
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##
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let br = hike.legs[^2].wp
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var xt = VidVtxPair( # Rewrite `br`
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vid: br.vid,
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vtx: VertexRef(
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vType: Extension,
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ePfx: NibblesBuf.nibble(nibble),
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eVid: br.vtx.bVid[nibble]))
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if 2 < hike.legs.len: # (1) or (2)
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let par = hike.legs[^3].wp
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case par.vtx.vType:
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of Branch: # (1)
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# Replace `br` (use `xt` as-is)
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discard
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of Extension: # (2)
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# Merge `br` into ^3 (update `xt`)
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db.disposeOfVtx((hike.root, xt.vid))
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xt.vid = par.vid
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xt.vtx.ePfx = par.vtx.ePfx & xt.vtx.ePfx
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of Leaf:
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return err((par.vid,DelLeafUnexpected))
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else: # (3)
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# Replace `br` (use `xt` as-is)
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discard
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db.layersPutVtx((hike.root, xt.vid), xt.vtx)
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ok()
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proc collapseExt(
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db: AristoDbRef; # Database, top layer
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hike: Hike; # Fully expanded path
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nibble: byte; # Link for `Branch` vertex `^2`
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vtx: VertexRef; # Follow up extension vertex (nibble)
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): Result[void,(VertexID,AristoError)] =
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## Convert/merge vertices:
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## ::
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## ^3 ^2 `vtx` | ^3 ^2 |
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## --------------------+-----------------------+------------------
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## Branch <br> Ext | Branch <ext> | 2 < legs.len (1)
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## Ext <br> Ext | <ext> | 2 < legs.len (2)
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## <br> Ext | <ext> | legs.len == 2 (3)
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##
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## Merge `vtx` into `br` and unlink `vtx`.
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##
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let br = hike.legs[^2].wp
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var xt = VidVtxPair( # Merge `vtx` into `br`
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vid: br.vid,
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vtx: VertexRef(
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vType: Extension,
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ePfx: NibblesBuf.nibble(nibble) & vtx.ePfx,
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eVid: vtx.eVid))
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db.disposeOfVtx((hike.root, br.vtx.bVid[nibble])) # `vtx` is obsolete now
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if 2 < hike.legs.len: # (1) or (2)
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let par = hike.legs[^3].wp
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case par.vtx.vType:
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of Branch: # (1)
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# Replace `br` by `^2 & vtx` (use `xt` as-is)
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discard
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of Extension: # (2)
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# Replace ^3 by `^3 & ^2 & vtx` (update `xt`)
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db.disposeOfVtx((hike.root, xt.vid))
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xt.vid = par.vid
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xt.vtx.ePfx = par.vtx.ePfx & xt.vtx.ePfx
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of Leaf:
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return err((par.vid,DelLeafUnexpected))
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else: # (3)
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# Replace ^2 by `^2 & vtx` (use `xt` as-is)
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discard
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db.layersPutVtx((hike.root, xt.vid), xt.vtx)
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ok()
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proc collapseLeaf(
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db: AristoDbRef; # Database, top layer
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hike: Hike; # Fully expanded path
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nibble: byte; # Link for `Branch` vertex `^2`
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vtx: VertexRef; # Follow up leaf vertex (from nibble)
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): Result[void,(VertexID,AristoError)] =
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## Convert/merge vertices:
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## ::
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## current | becomes | condition
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## | |
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## ^4 ^3 ^2 `vtx` | ^4 ^3 ^2 |
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## -------------------------+----------------------------+------------------
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## .. Branch <br> Leaf | .. Branch <Leaf> | 2 < legs.len (1)
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## Branch Ext <br> Leaf | Branch <Leaf> | 3 < legs.len (2)
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## Ext <br> Leaf | <Leaf> | legs.len == 3 (3)
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## <br> Leaf | <Leaf> | legs.len == 2 (4)
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##
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## Merge `<br>` and `Leaf` replacing one and removing the other.
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##
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let br = hike.legs[^2].wp
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var lf = VidVtxPair( # Merge `br` into `vtx`
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vid: br.vtx.bVid[nibble],
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vtx: VertexRef(
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vType: Leaf,
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lPfx: NibblesBuf.nibble(nibble) & vtx.lPfx,
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lData: vtx.lData))
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db.layersResKey((hike.root, lf.vid)) # `vtx` was modified
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if 2 < hike.legs.len: # (1), (2), or (3)
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db.disposeOfVtx((hike.root, br.vid)) # `br` is obsolete now
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# Merge `br` into the leaf `vtx` and unlink `br`.
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let par = hike.legs[^3].wp.dup # Writable vertex
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case par.vtx.vType:
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of Branch: # (1)
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# Replace `vtx` by `^2 & vtx` (use `lf` as-is)
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par.vtx.bVid[hike.legs[^3].nibble] = lf.vid
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db.layersPutVtx((hike.root, par.vid), par.vtx)
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db.layersPutVtx((hike.root, lf.vid), lf.vtx)
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return ok()
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of Extension: # (2) or (3)
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# Merge `^3` into `lf` but keep the leaf vertex ID unchanged. This
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# can avoid some extra updates.
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lf.vtx.lPfx = par.vtx.ePfx & lf.vtx.lPfx
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if 3 < hike.legs.len: # (2)
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# Grandparent exists
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let gpr = hike.legs[^4].wp.dup # Writable vertex
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if gpr.vtx.vType != Branch:
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return err((gpr.vid,DelBranchExpexted))
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db.disposeOfVtx((hike.root, par.vid)) # `par` is obsolete now
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gpr.vtx.bVid[hike.legs[^4].nibble] = lf.vid
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db.layersPutVtx((hike.root, gpr.vid), gpr.vtx)
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db.layersPutVtx((hike.root, lf.vid), lf.vtx)
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return ok()
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# No grandparent, so ^3 is root vertex # (3)
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db.layersPutVtx((hike.root, par.vid), lf.vtx)
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# Continue below
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of Leaf:
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return err((par.vid,DelLeafUnexpected))
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else: # (4)
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# Replace ^2 by `^2 & vtx` (use `lf` as-is) # `br` is root vertex
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db.layersUpdateVtx((hike.root, br.vid), lf.vtx)
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# Continue below
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# Clean up stale leaf vertex which has moved to root position
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db.disposeOfVtx((hike.root, lf.vid))
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ok()
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# -------------------------
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proc delSubTreeImpl(
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db: AristoDbRef; # Database, top layer
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root: VertexID; # Root vertex
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): Result[void,AristoError] =
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## Implementation of *delete* sub-trie.
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var
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dispose = @[root]
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rootVtx = db.getVtxRc((root, root)).valueOr:
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if error == GetVtxNotFound:
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return ok()
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return err(error)
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follow = @[rootVtx]
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# Collect list of nodes to delete
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while 0 < follow.len:
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var redo: seq[VertexRef]
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for vtx in follow:
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for vid in vtx.subVids:
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# Exiting here leaves the tree as-is
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let vtx = ? db.getVtxRc((root, vid))
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redo.add vtx
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dispose.add vid
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redo.swap follow
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# Mark collected vertices to be deleted
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for vid in dispose:
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db.disposeOfVtx((root, vid))
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ok()
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proc deleteImpl(
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db: AristoDbRef; # Database, top layer
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hike: Hike; # Fully expanded path
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): Result[void,(VertexID,AristoError)] =
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## Implementation of *delete* functionality.
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# Remove leaf entry
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let lf = hike.legs[^1].wp
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if lf.vtx.vType != Leaf:
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return err((lf.vid,DelLeafExpexted))
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db.disposeOfVtx((hike.root, lf.vid))
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if 1 < hike.legs.len:
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# Get current `Branch` vertex `br`
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let br = block:
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var wp = hike.legs[^2].wp
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wp.vtx = wp.vtx.dup # make sure that layers are not impliciteley modified
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wp
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if br.vtx.vType != Branch:
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return err((br.vid,DelBranchExpexted))
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# Unlink child vertex from structural table
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br.vtx.bVid[hike.legs[^2].nibble] = VertexID(0)
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db.layersPutVtx((hike.root, br.vid), br.vtx)
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# Clear all Merkle hash keys up to the root key
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for n in 0 .. hike.legs.len - 2:
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let vid = hike.legs[n].wp.vid
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db.layersResKey((hike.root, vid))
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let nibble = block:
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let rc = br.vtx.branchStillNeeded()
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if rc.isErr:
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return err((br.vid,DelBranchWithoutRefs))
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rc.value
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# Convert to `Extension` or `Leaf` vertex
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if 0 <= nibble:
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# Get child vertex (there must be one after a `Branch` node)
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let nxt = block:
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let vid = br.vtx.bVid[nibble]
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VidVtxPair(vid: vid, vtx: db.getVtx (hike.root, vid))
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if not nxt.vtx.isValid:
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return err((nxt.vid, DelVidStaleVtx))
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# Collapse `Branch` vertex `br` depending on `nxt` vertex type
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case nxt.vtx.vType:
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of Branch:
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? db.collapseBranch(hike, nibble.byte)
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of Extension:
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? db.collapseExt(hike, nibble.byte, nxt.vtx)
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of Leaf:
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? db.collapseLeaf(hike, nibble.byte, nxt.vtx)
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ok()
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# ------------------------------------------------------------------------------
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# Public functions
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# ------------------------------------------------------------------------------
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proc deleteAccountRecord*(
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db: AristoDbRef;
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accPath: Hash256;
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): Result[void,AristoError] =
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## Delete the account leaf entry addressed by the argument `path`. If this
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## leaf entry referres to a storage tree, this one will be deleted as well.
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##
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let
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hike = accPath.hikeUp(VertexID(1), db).valueOr:
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if error[1] in HikeAcceptableStopsNotFound:
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return err(DelPathNotFound)
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return err(error[1])
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stoID = hike.legs[^1].wp.vtx.lData.stoID
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# Delete storage tree if present
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if stoID.isValid:
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? db.delSubTreeImpl stoID
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db.deleteImpl(hike).isOkOr:
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return err(error[1])
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db.layersPutAccPayload(accPath, nil)
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ok()
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proc deleteGenericData*(
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db: AristoDbRef;
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root: VertexID;
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path: openArray[byte];
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): Result[bool,AristoError] =
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## Delete the leaf data entry addressed by the argument `path`. The MPT
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## sub-tree the leaf data entry is subsumed under is passed as argument
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## `root` which must be greater than `VertexID(1)` and smaller than
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## `LEAST_FREE_VID`.
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##
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## The return value is `true` if the argument `path` deleted was the last
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## one and the tree does not exist anymore.
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##
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# Verify that `root` is neither an accounts tree nor a strorage tree.
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if not root.isValid:
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return err(DelRootVidMissing)
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elif root == VertexID(1):
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return err(DelAccRootNotAccepted)
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elif LEAST_FREE_VID <= root.distinctBase:
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return err(DelStoRootNotAccepted)
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let hike = path.hikeUp(root, db).valueOr:
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if error[1] in HikeAcceptableStopsNotFound:
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return err(DelPathNotFound)
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return err(error[1])
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db.deleteImpl(hike).isOkOr:
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return err(error[1])
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ok(not db.getVtx((root, root)).isValid)
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proc deleteGenericTree*(
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db: AristoDbRef; # Database, top layer
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root: VertexID; # Root vertex
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): Result[void,AristoError] =
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## Variant of `deleteGenericData()` for purging the whole MPT sub-tree.
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##
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# Verify that `root` is neither an accounts tree nor a strorage tree.
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if not root.isValid:
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return err(DelRootVidMissing)
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elif root == VertexID(1):
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return err(DelAccRootNotAccepted)
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elif LEAST_FREE_VID <= root.distinctBase:
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return err(DelStoRootNotAccepted)
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db.delSubTreeImpl root
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proc deleteStorageData*(
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db: AristoDbRef;
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accPath: Hash256; # Implies storage data tree
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stoPath: Hash256;
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): Result[bool,AristoError] =
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## For a given account argument `accPath`, this function deletes the
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## argument `stoPath` from the associated storage tree (if any, at all.) If
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## the if the argument `stoPath` deleted was the last one on the storage tree,
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## account leaf referred to by `accPath` will be updated so that it will
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## not refer to a storage tree anymore. In the latter case only the function
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## will return `true`.
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##
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let
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accHike = db.fetchAccountHike(accPath).valueOr:
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if error == FetchAccInaccessible:
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return err(DelStoAccMissing)
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return err(error)
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wpAcc = accHike.legs[^1].wp
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stoID = wpAcc.vtx.lData.stoID
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if not stoID.isValid:
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return err(DelStoRootMissing)
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let stoHike = stoPath.hikeUp(stoID, db).valueOr:
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if error[1] in HikeAcceptableStopsNotFound:
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return err(DelPathNotFound)
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return err(error[1])
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# Mark account path Merkle keys for update
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db.updateAccountForHasher accHike
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db.deleteImpl(stoHike).isOkOr:
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return err(error[1])
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# Make sure that an account leaf has no dangling sub-trie
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if db.getVtx((stoID, stoID)).isValid:
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return ok(false)
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# De-register the deleted storage tree from the account record
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let leaf = wpAcc.vtx.dup # Dup on modify
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leaf.lData.stoID = VertexID(0)
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db.layersPutAccPayload(accPath, leaf.lData)
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db.layersPutVtx((accHike.root, wpAcc.vid), leaf)
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db.layersResKey((accHike.root, wpAcc.vid))
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ok(true)
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proc deleteStorageTree*(
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db: AristoDbRef; # Database, top layer
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accPath: Hash256; # Implies storage data tree
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): Result[void,AristoError] =
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## Variant of `deleteStorageData()` for purging the whole storage tree
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## associated to the account argument `accPath`.
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##
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let
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accHike = db.fetchAccountHike(accPath).valueOr:
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if error == FetchAccInaccessible:
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return err(DelStoAccMissing)
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return err(error)
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wpAcc = accHike.legs[^1].wp
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stoID = wpAcc.vtx.lData.stoID
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if not stoID.isValid:
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return err(DelStoRootMissing)
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# Mark account path Merkle keys for update
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db.updateAccountForHasher accHike
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? db.delSubTreeImpl stoID
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# De-register the deleted storage tree from the accounts record
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let leaf = wpAcc.vtx.dup # Dup on modify
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leaf.lData.stoID = VertexID(0)
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db.layersPutAccPayload(accPath, leaf.lData)
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db.layersPutVtx((accHike.root, wpAcc.vid), leaf)
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db.layersResKey((accHike.root, wpAcc.vid))
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ok()
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# ------------------------------------------------------------------------------
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# End
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# ------------------------------------------------------------------------------
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