eth_getBalance in p2p

nimbus/rpc/p2p.nim

@@ -6,10 +6,42 @@
 # at your option.
 # This file may not be copied, modified, or distributed except according to
 # those terms.
-import nimcrypto, json_rpc/server, eth_p2p
-import ../config
+import
+  nimcrypto, json_rpc/server, eth_p2p, hexstrings, strutils, stint,
+  ../config, ../vm_state, ../constants, eth_trie/[memdb, types],
+  ../db/[db_chain, state_db], eth_common
+
+proc headerFromTag(chain:BaseChainDB, blockTag: string): BlockHeader =
+  let tag = blockTag.string.toLowerAscii
+  case tag
+  of "latest": result = chain.getCanonicalHead()
+  of "earliest": result = chain.getCanonicalBlockHeaderByNumber(GENESIS_BLOCK_NUMBER)
+  of "pending":
+    #TODO
+    raise newException(ValueError, "Pending tag not yet implemented")
+  else:
+    # Raises are trapped and wrapped in JSON when returned to the user.
+    tag.validateRaiseHexQuantity
+    let blockNum = stint.fromHex(UInt256, tag)
+    result = chain.getCanonicalBlockHeaderByNumber(blockNum)
 
 proc setupP2PRPC*(server: EthereumNode, rpcsrv: RpcServer) =
   rpcsrv.rpc("net_version") do() -> uint:
     let conf = getConfiguration()
     result = conf.net.networkId
+
+  rpcsrv.rpc("eth_getBalance") do(address: array[20, byte], quantityTag: string) -> int:
+    ## Returns the balance of the account of given address.
+    ##
+    ## data: address to check for balance.
+    ## quantityTag: integer block number, or the string "latest", "earliest" or "pending", see the default block parameter.
+    ## Returns integer of the current balance in wei.
+    template chain: untyped = BaseChainDB(server.chain) # TODO: Sensible casting
+    let
+      header = chain.headerFromTag(quantityTag)
+      vmState = newBaseVMState(header, chain)
+      account_db = vmState.readOnlyStateDb
+      balance = account_db.get_balance(address)
+
+    return balance.toInt
+