allow nimbus to read geth database

nimbus/db/accounts_cache.nim

@@ -222,6 +222,9 @@ proc persistMode(acc: RefAccount): PersistMode =
 
 proc persistCode(acc: RefAccount, db: TrieDatabaseRef) =
   if acc.code.len != 0:
+    when defined(geth):
+      db.put(acc.account.codeHash.data, acc.code)
+    else:
       db.put(contractHashKey(acc.account.codeHash).toOpenArray, acc.code)
 
 proc persistStorage(acc: RefAccount, db: TrieDatabaseRef) =
@@ -282,8 +285,12 @@ proc getCode*(ac: AccountsCache, address: EthAddress): seq[byte] =
 
   if CodeLoaded in acc.flags or CodeChanged in acc.flags:
     result = acc.code
+  else:
+    when defined(geth):
+      let data = ac.db.get(acc.account.codeHash.data)
     else:
       let data = ac.db.get(contractHashKey(acc.account.codeHash).toOpenArray)
+
     acc.code = data
     acc.flags.incl CodeLoaded
     result = acc.code
@@ -411,9 +418,10 @@ iterator storage*(ac: AccountsCache, address: EthAddress): (UInt256, UInt256) =
     let storageRoot = acc.account.storageRoot
     var trie = initHexaryTrie(ac.db, storageRoot)
 
-    for slot, value in trie:
+    for slotHash, value in trie:
-      if slot.len != 0:
+      if slotHash.len == 0: continue
-        var keyData = ac.db.get(slotHashToSlotKey(slot).toOpenArray)
+      let keyData = ac.db.get(slotHashToSlotKey(slotHash).toOpenArray)
+      if keyData.len == 0: continue
       yield (rlp.decode(keyData, UInt256), rlp.decode(value, UInt256))
 
 proc getStorageRoot*(ac: AccountsCache, address: EthAddress): Hash256 =

nimbus/db/geth_db.nim

@@ -0,0 +1,35 @@
+import eth/[rlp, common], db_chain, eth/trie/db
+
+const
+  headerPrefix     = 'h'.byte # headerPrefix + num (uint64 big endian) + hash -> header
+  headerHashSuffix = 'n'.byte # headerPrefix + num (uint64 big endian) + headerHashSuffix -> hash
+  blockBodyPrefix  = 'b'.byte # blockBodyPrefix + num (uint64 big endian) + hash -> block body
+
+proc headerHash*(db: BaseChainDB, number: uint64): Hash256 =
+  var key: array[10, byte]
+  key[0] = headerPrefix
+  key[1..8] = toBytesBE(number)[0..^1]
+  key[^1] = headerHashSuffix
+  let res = db.db.get(key)
+  doAssert(res.len == 32)
+  result.data[0..31] = res[0..31]
+
+proc blockHeader*(db: BaseChainDB, hash: Hash256, number: uint64): BlockHeader =
+  var key: array[41, byte]
+  key[0] = headerPrefix
+  key[1..8] = toBytesBE(number)[0..^1]
+  key[9..40] = hash.data[0..^1]
+  let res = db.db.get(key)
+  result = rlp.decode(res, BlockHeader)
+
+proc blockHeader*(db: BaseChainDB, number: uint64): BlockHeader =
+  let hash = db.headerHash(number)
+  db.blockHeader(hash, number)
+
+proc blockBody*(db: BaseChainDB, hash: Hash256, number: uint64): BlockBody =
+  var key: array[41, byte]
+  key[0] = blockBodyPrefix
+  key[1..8] = toBytesBE(number)[0..^1]
+  key[9..40] = hash.data[0..^1]
+  let res = db.db.get(key)
+  result = rlp.decode(res, BlockBody)

nimbus/p2p/executor.nim

@@ -150,6 +150,9 @@ proc processBlock*(chainDB: BaseChainDB, header: BlockHeader, body: BlockBody, v
 
   let stateDb = vmState.accountDb
   if header.stateRoot != stateDb.rootHash:
+    when defined(geth):
+      error "Wrong state root in block", blockNumber=header.blockNumber, expected=header.stateRoot, actual=stateDb.rootHash
+    else:
       error "Wrong state root in block", blockNumber=header.blockNumber, expected=header.stateRoot, actual=stateDb.rootHash, arrivedFrom=chainDB.getCanonicalHead().stateRoot
     # this one is a show stopper until we are confident in our VM's
     # compatibility with the main chain

nimbus/tracer.nim

@@ -5,6 +5,13 @@ import
   chronicles, rpc/hexstrings, launcher,
   vm/interpreter/vm_forks, ./config
 
+when defined(geth):
+  import db/geth_db
+
+  proc getParentHeader(db: BaseChainDB, header: BlockHeader): BlockHeader =
+    db.blockHeader(header.blockNumber.truncate(uint64) - 1)
+
+else:
   proc getParentHeader(self: BaseChainDB, header: BlockHeader): BlockHeader =
     self.getBlockHeader(header.parentHash)
 

nimbus/vm_state.nim

@@ -75,6 +75,9 @@ method difficulty*(vmState: BaseVMState): UInt256 {.base, gcsafe.} =
 method gasLimit*(vmState: BaseVMState): GasInt {.base, gcsafe.} =
   vmState.blockHeader.gasLimit
 
+when defined(geth):
+  import db/geth_db
+
 method getAncestorHash*(vmState: BaseVMState, blockNumber: BlockNumber): Hash256 {.base, gcsafe.} =
   var ancestorDepth = vmState.blockHeader.blockNumber - blockNumber - 1
   if ancestorDepth >= constants.MAX_PREV_HEADER_DEPTH:
@@ -82,6 +85,9 @@ method getAncestorHash*(vmState: BaseVMState, blockNumber: BlockNumber): Hash256
   if blockNumber >= vmState.blockHeader.blockNumber:
     return
 
+  when defined(geth):
+    result = vmState.chainDB.headerHash(blockNumber.truncate(uint64))
+  else:
     result = vmState.chainDB.getBlockHash(blockNumber)
   #TODO: should we use deque here?
   # someday we may revive this code when