From d30f434f039ec615cbb16cb6069e87a55c4a5fe7 Mon Sep 17 00:00:00 2001
From: andri lim <jangko128@gmail.com>
Date: Thu, 9 Jan 2020 17:40:39 +0700
Subject: [PATCH] get rid of computation child after execution

---
 nimbus/vm/computation.nim        | 29 ++++++++++++++---------------
 nimbus/vm_state.nim              |  2 +-
 nimbus/vm_state_transactions.nim |  6 +-----
 nimbus/vm_types.nim              |  3 +--
 4 files changed, 17 insertions(+), 23 deletions(-)

diff --git a/nimbus/vm/computation.nim b/nimbus/vm/computation.nim
index dbfa45861..1f89e6cb5 100644
--- a/nimbus/vm/computation.nim
+++ b/nimbus/vm/computation.nim
@@ -24,7 +24,6 @@ proc newBaseComputation*(vmState: BaseVMState, blockNumber: BlockNumber, message
   result.memory = Memory()
   result.stack = newStack()
   result.gasMeter.init(message.gas)
-  result.children = @[]
   result.touchedAccounts = initHashSet[EthAddress]()
   result.suicides = initHashSet[EthAddress]()
   result.code = newCodeStream(message.code)
@@ -200,6 +199,11 @@ proc applyMessage*(computation: BaseComputation, opCode: static[Op]) =
   executeOpcodes(computation)
 
 proc addChildComputation*(computation: BaseComputation, child: BaseComputation) =
+  if child.isError or computation.getFork == FKIstanbul:
+    if not child.msg.isCreate:
+      if child.msg.contractAddress == ripemdAddr:
+        child.vmState.touchedAccounts.incl child.msg.contractAddress
+
   if child.isError:
     if child.shouldBurnGas:
       computation.returnData = @[]
@@ -218,9 +222,9 @@ proc addChildComputation*(computation: BaseComputation, child: BaseComputation)
 
   if not child.shouldBurnGas:
     computation.gasMeter.returnGas(child.gasMeter.gasRemaining)
-  computation.children.add(child)
 
 proc registerAccountForDeletion*(c: BaseComputation, beneficiary: EthAddress) =
+  c.touchedAccounts.incl beneficiary
   c.touchedAccounts.incl beneficiary
   c.suicides.incl(c.msg.contractAddress)
 
@@ -248,26 +252,21 @@ proc getGasRemaining*(c: BaseComputation): GasInt =
   else:
     result = c.gasMeter.gasRemaining
 
-# TODO: collecting touched accounts should be done in account state db
-proc collectTouchedAccounts*(c: BaseComputation, output: var HashSet[EthAddress], ancestorHadError: bool = false) =
+proc collectTouchedAccounts*(c: BaseComputation) =
   ## Collect all of the accounts that *may* need to be deleted based on EIP161:
   ## https://github.com/ethereum/EIPs/blob/master/EIPS/eip-161.md
   ## also see: https://github.com/ethereum/EIPs/issues/716
 
-  let isIstanbul = c.getFork >= FkIstanbul
-  let condition = c.isError or ancestorHadError
-
-  if not c.msg.isCreate:
-    if condition:
+  if c.isSuccess:
+    if not c.msg.isCreate:
+      c.touchedAccounts.incl c.msg.contractAddress
+    c.vmState.touchedAccounts.incl c.touchedAccounts
+  else:
+    if not c.msg.isCreate:
       # Special case to account for geth+parity bug
       # https://github.com/ethereum/EIPs/issues/716
       if c.msg.contractAddress == ripemdAddr:
-        output.incl c.msg.contractAddress
-
-  if c.isSuccess or isIstanbul:
-  # recurse into nested computations (even errored ones, since looking for RIPEMD160)
-    for child in c.children:
-      child.collectTouchedAccounts(output, c.isError or ancestorHadError)
+        c.vmState.touchedAccounts.incl c.msg.contractAddress
 
 proc tracingEnabled*(c: BaseComputation): bool =
   c.vmState.tracingEnabled
diff --git a/nimbus/vm_state.nim b/nimbus/vm_state.nim
index fce3e6f78..5eb9b0657 100644
--- a/nimbus/vm_state.nim
+++ b/nimbus/vm_state.nim
@@ -35,7 +35,7 @@ proc init*(self: BaseVMState, prevStateRoot: Hash256, header: BlockHeader,
   self.tracingEnabled = TracerFlags.EnableTracing in tracerFlags
   self.logEntries = @[]
   self.accountDb = newAccountStateDB(chainDB.db, prevStateRoot, chainDB.pruneTrie)
-  self.touchedAccounts = initHashSet[EthAddress]()
+  self.touchedAccounts = initHashSet[EthAddress]()  
 
 proc newBaseVMState*(prevStateRoot: Hash256, header: BlockHeader,
                      chainDB: BaseChainDB, tracerFlags: set[TracerFlags] = {}): BaseVMState =
diff --git a/nimbus/vm_state_transactions.nim b/nimbus/vm_state_transactions.nim
index b6561f9a2..f386211f4 100644
--- a/nimbus/vm_state_transactions.nim
+++ b/nimbus/vm_state_transactions.nim
@@ -78,11 +78,7 @@ proc execComputation*(computation: var BaseComputation) =
     computation.gasMeter.refundGas(RefundSelfDestruct * suicidedCount)
 
   if computation.getFork >= FkSpurious:
-    computation.collectTouchedAccounts(computation.vmState.touchedAccounts)
-    if computation.isSuccess:
-      if not computation.msg.isCreate:
-        computation.touchedAccounts.incl computation.msg.contractAddress
-      computation.vmState.touchedAccounts.incl computation.touchedAccounts
+    computation.collectTouchedAccounts()
 
   computation.vmstate.status = computation.isSuccess
   if computation.isSuccess:
diff --git a/nimbus/vm_types.nim b/nimbus/vm_types.nim
index 4fc0ef144..941176a6f 100644
--- a/nimbus/vm_types.nim
+++ b/nimbus/vm_types.nim
@@ -59,11 +59,10 @@ type
     stack*:                 Stack
     gasMeter*:              GasMeter
     code*:                  CodeStream
-    children*:              seq[BaseComputation]
     rawOutput*:             seq[byte]
     returnData*:            seq[byte]
     error*:                 Error
-    touchedAccounts*:       HashSet[EthAddress]
+    touchedAccounts*:       HashSet[EthAddress]    
     suicides*:              HashSet[EthAddress]
     gasCosts*:              GasCosts # TODO - will be hidden at a lower layer
     forkOverride*:          Option[Fork]