130 lines
3.9 KiB
Nim
130 lines
3.9 KiB
Nim
# nimbus-eth1
|
|
# Copyright (c) 2023-2024 Status Research & Development GmbH
|
|
# Licensed under either of
|
|
# * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or
|
|
# http://www.apache.org/licenses/LICENSE-2.0)
|
|
# * MIT license ([LICENSE-MIT](LICENSE-MIT) or
|
|
# http://opensource.org/licenses/MIT)
|
|
# at your option. This file may not be copied, modified, or distributed
|
|
# except according to those terms.
|
|
|
|
## Aristo DB -- Transaction fork helpers
|
|
## =====================================
|
|
##
|
|
{.push raises: [].}
|
|
|
|
import
|
|
results,
|
|
./tx_frame,
|
|
".."/[aristo_desc, aristo_get, aristo_layers]
|
|
|
|
# ------------------------------------------------------------------------------
|
|
# Public functions
|
|
# ------------------------------------------------------------------------------
|
|
|
|
proc txFork*(
|
|
tx: AristoTxRef; # Transaction descriptor
|
|
): Result[AristoDbRef,AristoError] =
|
|
## Clone a transaction into a new DB descriptor accessing the same backend
|
|
## database (if any) as the argument `db`. The new descriptor is linked to
|
|
## the transaction parent and is fully functional as a forked instance (see
|
|
## comments on `aristo_desc.reCentre()` for details.)
|
|
##
|
|
## Input situation:
|
|
## ::
|
|
## tx -> db0 with tx is top transaction, tx.level > 0
|
|
##
|
|
## Output situation:
|
|
## ::
|
|
## tx -> db0 \
|
|
## > share the same backend
|
|
## tx1 -> db1 /
|
|
##
|
|
## where `tx.level > 0`, `db1.level == 1` and `db1` is returned. The
|
|
## transaction `tx1` can be retrieved via `db1.txTop()`.
|
|
##
|
|
## The new DB descriptor will contain a copy of the argument transaction
|
|
## `tx` as top layer of level 1 (i.e. this is he only transaction.) Rolling
|
|
## back will end up at the backend layer (incl. backend filter.)
|
|
##
|
|
## Use `aristo_desc.forget()` to clean up this descriptor.
|
|
##
|
|
let db = tx.db
|
|
|
|
# Verify `tx` argument
|
|
if db.txRef == tx:
|
|
if db.top.txUid != tx.txUid:
|
|
return err(TxArgStaleTx)
|
|
elif db.stack.len <= tx.level:
|
|
return err(TxArgStaleTx)
|
|
elif db.stack[tx.level].txUid != tx.txUid:
|
|
return err(TxArgStaleTx)
|
|
|
|
# Provide new empty stack layer
|
|
let stackLayer = block:
|
|
let rc = db.getTuvBE()
|
|
if rc.isOk:
|
|
LayerRef(vTop: rc.value)
|
|
elif rc.error == GetTuvNotFound:
|
|
LayerRef.init()
|
|
else:
|
|
return err(rc.error)
|
|
|
|
# Set up clone associated to `db`
|
|
let txClone = ? db.fork(noToplayer = true, noFilter = false)
|
|
txClone.top = db.layersCc tx.level # Provide tx level 1 stack
|
|
txClone.stack = @[stackLayer] # Zero level stack
|
|
txClone.top.txUid = 1
|
|
txClone.txUidGen = 1
|
|
|
|
# Install transaction similar to `tx` on clone
|
|
txClone.txRef = AristoTxRef(
|
|
db: txClone,
|
|
txUid: 1,
|
|
level: 1)
|
|
|
|
ok(txClone)
|
|
|
|
|
|
proc txForkTop*(
|
|
db: AristoDbRef;
|
|
): Result[AristoDbRef,AristoError] =
|
|
## Variant of `forkTx()` for the top transaction if there is any. Otherwise
|
|
## the top layer is cloned, and an empty transaction is set up. After
|
|
## successful fork the returned descriptor has transaction level 1.
|
|
##
|
|
## Use `aristo_desc.forget()` to clean up this descriptor.
|
|
##
|
|
if db.txRef.isNil:
|
|
let txClone = ? db.fork(noToplayer=true, noFilter=false)
|
|
txClone.top = db.layersCc # Is a deep copy
|
|
|
|
discard txClone.txFrameBegin()
|
|
return ok(txClone)
|
|
# End if()
|
|
|
|
db.txRef.txFork()
|
|
|
|
|
|
proc txForkBase*(
|
|
db: AristoDbRef;
|
|
): Result[AristoDbRef,AristoError] =
|
|
## Variant of `forkTx()`, sort of the opposite of `forkTop()`. This is the
|
|
## equivalent of top layer forking after all tranactions have been rolled
|
|
## back.
|
|
##
|
|
## Use `aristo_desc.forget()` to clean up this descriptor.
|
|
##
|
|
if db.txRef.isNil:
|
|
return db.txForkTop()
|
|
|
|
let txClone = ? db.fork(noToplayer=true, noFilter=false)
|
|
txClone.top = db.layersCc 0
|
|
|
|
discard txClone.txFrameBegin()
|
|
ok(txClone)
|
|
|
|
# ------------------------------------------------------------------------------
|
|
# End
|
|
# ------------------------------------------------------------------------------
|