Finish the Spec/Epoch types refactoring

beacon_chain/spec/beaconstate.nim

@@ -218,7 +218,7 @@ func get_genesis_beacon_state*(
 
   for i in 0 ..< SHARD_COUNT:
     state.latest_crosslinks[i] = Crosslink(
-      epoch: GENESIS_EPOCH.uint64, crosslink_data_root: ZERO_HASH)
+      epoch: GENESIS_EPOCH, crosslink_data_root: ZERO_HASH)
 
   # Process genesis deposits
   for deposit in genesis_validator_deposits:
@@ -401,8 +401,7 @@ proc checkAttestation*(
     return
 
   let expected_justified_block_root =
-    get_block_root(
-      state, get_epoch_start_slot(attestation.data.justified_epoch.Epoch))
+    get_block_root(state, get_epoch_start_slot(attestation.data.justified_epoch))
   if not (attestation.data.justified_block_root == expected_justified_block_root):
     warn("Unexpected justified block root",
       attestation_justified_block_root = attestation.data.justified_block_root,
@@ -413,7 +412,7 @@ proc checkAttestation*(
       attestation.data.latest_crosslink,
       Crosslink(
         crosslink_data_root: attestation.data.crosslink_data_root,
-        epoch: slot_to_epoch(attestation_data_slot).uint64)]):
+        epoch: slot_to_epoch(attestation_data_slot))]):
     warn("Unexpected crosslink shard",
       state_latest_crosslinks_attestation_data_shard =
         state.latest_crosslinks[attestation.data.shard],
@@ -516,12 +515,12 @@ proc makeAttestationData*(
     justified_block_root = get_block_root(state, justified_slot)
 
   AttestationData(
-    slot: state.slot.uint64,
+    slot: state.slot,
     shard: shard,
     beacon_block_root: beacon_block_root,
     epoch_boundary_root: epoch_boundary_root,
     crosslink_data_root: Eth2Digest(), # Stub in phase0
     latest_crosslink: state.latest_crosslinks[shard],
-    justified_epoch: state.justified_epoch.uint64,
+    justified_epoch: state.justified_epoch,
     justified_block_root: justified_block_root,
   )

beacon_chain/spec/datatypes.nim

@@ -18,7 +18,8 @@
 # types / composition
 
 import
-  eth/common, hashes, math,
+  hashes, math,
+  eth/[common, rlp],
   ./crypto, ./digest
 
 # TODO Data types:
@@ -228,7 +229,7 @@ type
 
   # https://github.com/ethereum/eth2.0-specs/blob/0.4.0/specs/core/0_beacon-chain.md#attestationdata
   AttestationData* = object
-    slot*: uint64 ##\
+    slot*: Slot ##\
     ## Slot number
 
     shard*: uint64 ##\
@@ -246,7 +247,7 @@ type
     latest_crosslink*: Crosslink ##\
     ## Last crosslink
 
-    justified_epoch*: uint64 ##\
+    justified_epoch*: Epoch ##\
     ## Last justified epoch in the beacon state
 
     justified_block_root*: Eth2Digest ##\
@@ -284,7 +285,7 @@ type
   # https://github.com/ethereum/eth2.0-specs/blob/0.4.0/specs/core/0_beacon-chain.md#voluntaryexit
   VoluntaryExit* = object
     # Minimum epoch for processing exit
-    epoch*: uint64
+    epoch*: Epoch
     # Index of the exiting validator
     validator_index*: uint64
     # Validator signature
@@ -451,7 +452,7 @@ type
 
   # https://github.com/ethereum/eth2.0-specs/blob/0.4.0/specs/core/0_beacon-chain.md#crosslink
   Crosslink* = object
-    epoch*: uint64 ##\
+    epoch*: Epoch ##\
     ## Epoch number
 
     crosslink_data_root*: Eth2Digest ##\
@@ -522,7 +523,7 @@ type
 func shortValidatorKey*(state: BeaconState, validatorIdx: int): string =
     ($state.validator_registry[validatorIdx].pubkey)[0..7]
 
-template ethTimeUnit(typ: type) =
+template ethTimeUnit(typ: type) {.dirty.} =
   proc `+`*(x: typ, y: uint64): typ {.borrow.}
   proc `-`*(x: typ, y: uint64): typ {.borrow.}
   proc `-`*(x: uint64, y: typ): typ {.borrow.}
@@ -554,13 +555,26 @@ template ethTimeUnit(typ: type) =
   proc `$`*(x: typ): string {.borrow.}
   proc hash*(x: typ): Hash {.borrow.}
 
-ethTimeUnit(Slot)
-ethTimeUnit(Epoch)
+  # Serialization
+  proc read*(rlp: var Rlp, T: type typ): typ {.inline.} =
+    typ(rlp.read(uint64))
 
-func humaneSlotNum*(s: auto): uint64 =
+  proc append*(writer: var RlpWriter, value: typ) =
+    writer.append uint64(value)
+
+  proc writeValue*(writer: var JsonWriter, value: typ) =
+    writeValue(writer, uint64 value)
+
+  proc readValue*(reader: var JsonReader, value: var typ) =
+    value = typ reader.readValue(uint64)
+
+ethTimeUnit Slot
+ethTimeUnit Epoch
+
+func humaneSlotNum*(s: Slot): uint64 =
   s.Slot - GENESIS_SLOT
 
-func humaneEpochNum*(e: auto): uint64 =
+func humaneEpochNum*(e: Epoch): uint64 =
   e.Epoch - GENESIS_EPOCH
 
 import nimcrypto, json_serialization

beacon_chain/spec/helpers.nim

@@ -218,11 +218,13 @@ func bytes_to_int*(data: seq[byte]): uint64 =
 
 # https://github.com/ethereum/eth2.0-specs/blob/0.4.0/specs/core/0_beacon-chain.md#int_to_bytes1-int_to_bytes2-
 # Have 1, 4, and 32-byte versions. 2+ more and maybe worth metaprogramming.
-func int_to_bytes32*(x: uint64|Epoch) : array[32, byte] =
+func int_to_bytes32*(x: uint64): array[32, byte] =
   ## Little-endian data representation
   ## TODO remove uint64 when those callers fade away
   for i in 0 ..< 8:
-    result[24 + i] = byte((x.uint64 shr i*8) and 0xff)
+    result[24 + i] = byte((x shr i*8) and 0xff)
+
+func int_to_bytes32*(x: Epoch): array[32, byte] {.borrow.}
 
 func int_to_bytes1*(x: int): array[1, byte] =
   assert x >= 0

beacon_chain/state_transition.nim

@@ -304,7 +304,7 @@ proc processExits(
     if skipValidation notin flags:
       if not bls_verify(
           validator.pubkey, signed_root(exit, "signature"), exit.signature,
-          get_domain(state.fork, exit.epoch.Epoch, DOMAIN_EXIT)):
+          get_domain(state.fork, exit.epoch, DOMAIN_EXIT)):
         notice "Exit: invalid signature"
         return false
 
@@ -717,7 +717,7 @@ func processEpoch(state: var BeaconState) =
         if 3'u64 * total_attesting_balance(crosslink_committee) >=
             2'u64 * get_total_balance(state, crosslink_committee.committee):
           state.latest_crosslinks[crosslink_committee.shard] = Crosslink(
-            epoch: slot_to_epoch(slot).uint64,
+            epoch: slot_to_epoch(slot),
             crosslink_data_root: winning_root(crosslink_committee))
 
   # https://github.com/ethereum/eth2.0-specs/blob/0.4.0/specs/core/0_beacon-chain.md#rewards-and-penalties
@@ -745,7 +745,7 @@ func processEpoch(state: var BeaconState) =
       for v in get_attestation_participants(
           state, a.data, a.aggregation_bitfield):
         if v notin result:
-          result[v] = a.inclusion_slot - a.data.slot
+          result[v] = Slot(a.inclusion_slot - a.data.slot)
 
   block: # Justification and finalization
     let

beacon_chain/sync_protocol.nim

@@ -1,7 +1,7 @@
 import
   options, tables,
   chronicles, chronos, ranges/bitranges,
-  spec/[datatypes, crypto, digest],
+  spec/[datatypes, crypto, digest], eth/rlp,
   beacon_node_types, eth2_network, beacon_chain_db, block_pool, time, ssz
 
 from beacon_node import onBeaconBlock
@@ -43,7 +43,10 @@ proc fromHeaderAndBody(b: var BeaconBlock, h: BeaconBlockHeader, body: BeaconBlo
   b.signature = h.signature
   b.body = body
 
-proc importBlocks(node: BeaconNode, roots: openarray[(Eth2Digest, uint64)], headers: openarray[BeaconBlockHeader], bodies: openarray[BeaconBlockBody]) =
+proc importBlocks(node: BeaconNode,
+                  roots: openarray[(Eth2Digest, Slot)],
+                  headers: openarray[BeaconBlockHeader],
+                  bodies: openarray[BeaconBlockBody]) =
   var bodyMap = initTable[Eth2Digest, int]()
 
   for i, b in bodies:
@@ -74,9 +77,9 @@ p2pProtocol BeaconSync(version = 1,
 
     var
       latestFinalizedRoot: Eth2Digest # TODO
-      latestFinalizedEpoch: uint64 = node.state.data.finalized_epoch.uint64
+      latestFinalizedEpoch = node.state.data.finalized_epoch
       bestRoot: Eth2Digest # TODO
-      bestSlot: uint64 = node.state.data.slot.uint64
+      bestSlot = node.state.data.slot
 
     let m = await handshake(peer, timeout = 500,
                             status(networkId, latestFinalizedRoot,
@@ -94,11 +97,11 @@ p2pProtocol BeaconSync(version = 1,
         # Send roots
         # TODO: Currently we send all block roots in one "packet". Maybe
         # they should be split to multiple packets.
-        type Root = (Eth2Digest, uint64)
+        type Root = (Eth2Digest, Slot)
         var roots = newSeqOfCap[Root](128)
-        for i in m.bestSlot .. bestSlot:
-          for r in blockPool.blockRootsForSlot(i):
-            roots.add((r, i))
+        for i in int(m.bestSlot) .. int(bestSlot):
+          for r in blockPool.blockRootsForSlot(i.Slot):
+            roots.add((r, i.Slot))
 
         await peer.beaconBlockRoots(roots)
       else:
@@ -115,28 +118,28 @@ p2pProtocol BeaconSync(version = 1,
             peer: Peer,
             networkId: int,
             latestFinalizedRoot: Eth2Digest,
-            latestFinalizedEpoch: uint64,
+            latestFinalizedEpoch: Epoch,
             bestRoot: Eth2Digest,
-            bestSlot: uint64) {.libp2pProtocol("hello", "1.0.0").}
+            bestSlot: Slot) {.libp2pProtocol("hello", "1.0.0").}
 
   proc beaconBlockRoots(
             peer: Peer,
-            roots: openarray[(Eth2Digest, uint64)]) {.libp2pProtocol("rpc/beacon_block_roots", "1.0.0").}
+            roots: openarray[(Eth2Digest, Slot)]) {.libp2pProtocol("rpc/beacon_block_roots", "1.0.0").}
 
   requestResponse:
     proc getBeaconBlockHeaders(
             peer: Peer,
             blockRoot: Eth2Digest,
-            slot: uint64,
+            slot: Slot,
             maxHeaders: int,
             skipSlots: int) {.libp2pProtocol("rpc/beacon_block_headers", "1.0.0").} =
       # TODO: validate maxHeaders and implement slipSlots
-      var s = slot
+      var s = slot.int
       var headers = newSeqOfCap[BeaconBlockHeader](maxHeaders)
       let db = peer.networkState.db
       let blockPool = peer.networkState.node.blockPool
       while headers.len < maxHeaders:
-        for r in blockPool.blockRootsForSlot(s):
+        for r in blockPool.blockRootsForSlot(s.Slot):
           headers.add(db.getBlock(r).get().toHeader)
           if headers.len == maxHeaders: break
         inc s