fix traceTransaction

nimbus/tracer.nim

@@ -1,24 +1,44 @@
 import
-  db/[db_chain, state_db], eth_common, utils, json,
-  constants, vm_state, vm_types, transaction, p2p/chain
+  db/[db_chain, state_db, capturedb], eth_common, utils, json,
+  constants, vm_state, vm_types, transaction, p2p/chain,
+  eth_trie/db, nimcrypto
+
+proc getParentHeader(self: BaseChainDB, header: BlockHeader): BlockHeader =
+  self.getBlockHeader(header.parentHash)
+
+proc prefixHex(x: openArray[byte]): string =
+  "0x" & toHex(x, true)
 
 proc traceTransaction*(db: BaseChainDB, header: BlockHeader,
                        body: BlockBody, txIndex: int, tracerFlags: set[TracerFlags]): JsonNode =
-  let head = db.getCanonicalHead()
-  assert(head.blockNumber == header.blockNumber - 1)
-  var stateDb = newAccountStateDB(db.db, head.stateRoot, db.pruneTrie)
+  let parent = db.getParentHeader(header)
+  var stateDb = newAccountStateDB(db.db, parent.stateRoot, db.pruneTrie)
   assert(body.transactions.calcTxRoot == header.txRoot)
   if header.txRoot == BLANK_ROOT_HASH: return
 
-  let vmState = newBaseVMState(head, db, tracerFlags + {EnableTracing})
+  let
+    memoryDB = newMemoryDB()
+    captureDB = newCaptureDB(db.db, memoryDB)
+    captureTrieDB = trieDB captureDB
+    captureChainDB = newBaseChainDB(captureTrieDB, false) # prune or not prune?
+
+  let vmState = newBaseVMState(parent, captureChainDB, tracerFlags + {TracerFlags.EnableTracing})
   assert(body.transactions.len != 0)
 
+  var gasUsed: GasInt
   for idx, tx in body.transactions:
     var sender: EthAddress
     if tx.getSender(sender):
-      discard processTransaction(stateDb, tx, sender, vmState)
+      let txFee = processTransaction(stateDb, tx, sender, vmState)
+      gasUsed = (txFee div tx.gasPrice.u256).truncate(GasInt)
       if idx == txIndex: break
     else:
       assert(false, "Could not get sender")
 
-  vmState.getTracingResult()
+  result = vmState.getTracingResult()
+  result["gas"] = %gasUsed
+
+  var n = newJObject()
+  for k, v in pairsInMemoryDB(memoryDB):
+    n[k.prefixHex] = %v.prefixHex
+  result["snapshot"] = n

nimbus/vm/computation.nim

@@ -286,11 +286,14 @@ proc getGasRemaining*(c: BaseComputation): GasInt =
   else:
     result = c.gasMeter.gasRemaining
 
-template tracingEnabled*(c: BaseComputation): bool =
+proc tracingEnabled*(c: BaseComputation): bool =
   c.vmState.tracingEnabled
 
-template traceOpCodeStarted*(c: BaseComputation, op: string) =
+proc traceOpCodeStarted*(c: BaseComputation, op: string) =
   traceOpCodeStarted(c.vmState.tracer, c, op)
 
 proc traceOpCodeEnded*(c: BaseComputation) =
   c.vmState.tracer.traceOpCodeEnded(c)
+
+proc traceError*(c: BaseComputation) =
+  c.vmState.tracer.traceError(c)

nimbus/vm/transaction_tracer.nim

@@ -1,10 +1,19 @@
 import
   json, strutils,
   eth_common, stint, byteutils,
-  ../vm_types, memory, stack
+  ../vm_types, memory, stack,
+  ../db/[db_chain, state_db],
+  eth_trie/hexary, ./message,
+  ranges/typedranges
 
 proc initTracer*(tracer: var TransactionTracer, flags: set[TracerFlags] = {}) =
   tracer.trace = newJObject()
+
+  # make appear at the top of json object
+  tracer.trace["gas"] = %0
+  tracer.trace["failed"] = %false
+  tracer.trace["returnValue"] = %""
+
   tracer.trace["structLogs"] = newJArray()
   tracer.flags = flags
 
@@ -37,11 +46,32 @@ proc traceOpCodeStarted*(tracer: var TransactionTracer, c: BaseComputation, op:
       mem.add(%c.memory.bytes.toOpenArray(i * chunkLen, (i + 1) * chunkLen - 1).toHex())
     j["memory"] = mem
 
-  # TODO: log storage
+  # TODO: this seems very inefficient
+  # could we improve it?
+  # TODO: figure out how to get storage
+  # when contract excecution interrupted by exception
   if TracerFlags.DisableStorage notin tracer.flags:
-    let storage = newJArray()
+    var storage = newJObject()
+    var stateDB = c.vmState.chaindb.getStateDb(c.vmState.blockHeader.stateRoot, readOnly = true)
+    let storageRoot = stateDB.getStorageRoot(c.msg.storageAddress)
+    var trie = initHexaryTrie(c.vmState.chaindb.db, storageRoot)
+    for k, v in trie:
+      var key = k.toOpenArray.toHex
+      if key.len != 0:
+        storage[key] = %(v.toOpenArray.toHex)
     j["storage"] = storage
 
 proc traceOpCodeEnded*(tracer: var TransactionTracer, c: BaseComputation) =
   let j = tracer.trace["structLogs"].elems[^1]
   j["gasCost"] = %(tracer.gasRemaining - c.gasMeter.gasRemaining)
+
+proc traceError*(tracer: var TransactionTracer, c: BaseComputation) =
+  let j = tracer.trace["structLogs"].elems[^1]
+
+  # TODO: figure out how to get gasCost
+  # when contract execution failed before traceOpCodeEnded called
+  # because exception raised
+  #j["gasCost"] = %
+
+  j["error"] = %(c.error.info)
+  tracer.trace["failed"] = %true

nimbus/vm_state_transactions.nim

@@ -102,13 +102,14 @@ proc applyCreateTransaction*(db: var AccountStateDB, t: Transaction, vmState: Ba
       db.setCode(contractAddress, ByteRange())
     db.addBalance(sender, (t.gasLimit.u256 - gasUsed2 - codeCost.u256)*t.gasPrice.u256)
     return (gasUsed2 + codeCost.u256) * t.gasPrice.u256
-
   else:
     # FIXME: don't do this revert, but rather only subBalance correctly
     # the if transactionfailed at end is what is supposed to pick it up
     # especially when it's cross-function, it's ugly/fragile
     db.addBalance(sender, t.value)
     echo "isError: ", c.isError
+    if c.tracingEnabled:
+      c.traceError()
     return t.gasLimit.u256 * t.gasPrice.u256
 
 method executeTransaction(vmState: BaseVMState, transaction: Transaction): (BaseComputation, BlockHeader) {.base.}=