Greg/initial state && The Great Refactor

.gitignore

@@ -1,3 +1,4 @@
 .idea/
 node_modules/
-test:ethereum
+test:ethereum
+beaconChain/node_modules/

beaconChain/constants/constants.ts

@@ -5,12 +5,15 @@
 // Misc
 export const SHARD_COUNT = 2 ** 10; // 1024 shards
 export const TARGET_COMMITTEE_SIZE = 2 ** 8; // 256 validators
-export const MIN_BALANCE = 2 ** 4; // 16 ETH
+export const EJECTION_BALANCE = 2 ** 4; // 16 ETH
 export const MAX_BALANCE_CHURN_QUOTIENT = 2 ** 5; // 32
 export const GWEI_PER_ETH = 10 ** 9; // 1B Gwei/ETH
 export const BEACON_CHAIN_SHARD_NUMBER = 2 ** 64 - 1;
 export const BLS_WITHDRAWAL_PREFIX_BYTE = 0x00;
 export const MAX_CASPER_VOTES = 2 ** 10; // 1024 votes
+export const LATEST_BLOCK_ROOTS_LENGTH =  2 ** 13; // 8192 block roots
+export const LATEST_RANDAO_MIXES_LENGTH = 2 ** 13; // 8192 randao mixes
+export const EMPTY_SIGNATURE = [new Uint8Array(48), new Uint8Array(48)]; // [bytes48(0), bytes48(0)]
 
 // Deposit contract
 export const DEPOSIT_CONTRACT_ADDRESS = "TBD";

beaconChain/helpers/array.ts

@@ -0,0 +1,16 @@
+/**
+ * Takes two arrays and combines them similar to the Array.zip() form Python.
+ * a = [1,2,3] b = [4,5,6]
+ * c = zip(a,b) // [[1,4], [2,5], [3,6]]
+ * NOTE: Lodash would be an alternative, although theres no need *YET* to import lodash for one function.
+ * That being said there is one main caveat: if the arrays are not 1-1 in length it will return undefined
+ * but, this is fine for our use case since validatorBalances and validators must be 1-1 in length.
+ * @param {Array<T>} a
+ * @param {Array<X>} b
+ * @returns {(T | X)[][]}
+ */
+function zip<T, X>(a: T[], b: X[]): Array<Array<T|X>> {
+    return a.map((e, i) => [e, b[i]]);
+}
+
+export { zip };

beaconChain/helpers/stateTransitionHelpers.ts

@@ -1,6 +1,9 @@
 import { keccakAsU8a } from "@polkadot/util-crypto";
 // Helper functions related to state transition functions
-import { EPOCH_LENGTH, MAX_DEPOSIT, SHARD_COUNT, TARGET_COMMITTEE_SIZE } from "../constants/constants";
+import {
+  EPOCH_LENGTH, GWEI_PER_ETH, LATEST_BLOCK_ROOTS_LENGTH, MAX_DEPOSIT, SHARD_COUNT,
+  TARGET_COMMITTEE_SIZE,
+} from "../constants/constants";
 import { ValidatorStatusCodes } from "../constants/enums";
 import {AttestationData, BeaconBlock} from "../interfaces/blocks";
 import {BeaconState, ShardCommittee, ValidatorRecord} from "../interfaces/state";
@@ -186,12 +189,11 @@ function getShardCommitteesAtSlot(state: BeaconState, slot: int): ShardCommittee
  * @param {int} slot
  * @returns {hash32}
  */
-function getBlockHash(state: BeaconState, slot: int): hash32 {
-  const earliestSlotInArray = state.slot - state.latestBlockHashes.length;
-  if (earliestSlotInArray <= slot && slot < state.slot) {
-    throw new Error();
-  }
-  return state.latestBlockHashes[slot - earliestSlotInArray];
+function getBlockRoot(state: BeaconState, slot: int): hash32 {
+  // Returns the block root at a recent ``slot``.
+  if (state.slot <= slot + LATEST_BLOCK_ROOTS_LENGTH) { throw new Error(); }
+  if (slot < state.slot) { throw new Error(); }
+  return state.latestBlockRoots[slot % LATEST_BLOCK_ROOTS_LENGTH];
 }
 
 /**
@@ -200,7 +202,7 @@ function getBlockHash(state: BeaconState, slot: int): hash32 {
  * @param {int} slot
  * @returns {int}
  */
-function getBeaconProposerIndex(state: BeaconState, slot: int): int {
+export function getBeaconProposerIndex(state: BeaconState, slot: int): int {
   const firstCommittee = getShardCommitteesAtSlot(state, slot)[0].committee;
   return firstCommittee[slot % firstCommittee.length];
 }
@@ -231,8 +233,9 @@ function getAttestationParticipants(state: BeaconState, attestationData: Attesta
  * @returns {int}
  */
 // TODO Math.min requires int, validator.record is a uint64
-function getEffectiveBalance(validator: ValidatorRecord): int {
-  return Math.min(validator.balance, MAX_DEPOSIT);
+export function getEffectiveBalance(state: BeaconState, index: int): int {
+  // Returns the effective balance (also known as "balance at stake") for a ``validator`` with the given ``index``.
+  return Math.min(state.validatorBalances[index], MAX_DEPOSIT * GWEI_PER_ETH);
 }
 
 // TODO figure out what bytes1() does in python

beaconChain/interfaces/blocks.ts

@@ -6,7 +6,7 @@ type bytes = number;
 type uint24 = number;
 type uint64 = number;
 type uint384 = number;
-type hash32 = number;
+type hash32 = Uint8Array;
 
 // Beacon chain operations
 
@@ -82,22 +82,24 @@ export interface Deposit {
 
 export interface DepositData {
   // Deposit parameters
-  depositParameters: DepositParameters;
+  depositInput: DepositInput;
   // Value in Gwei
   value: uint64;
   // Timestamp from deposit contract
   timestamp: uint64;
 }
 
-export interface DepositParameters {
+export interface DepositInput {
   // BLS pubkey
   pubkey: uint384;
-  // BLS proof of possession (a BLS signature)
-  proofOfPossession: uint384[];
   // Withdrawal credentials
   withdrawalCredentials: hash32;
   // Initial RANDAO commitment
   randaoCommitment: hash32;
+  // Initial custody commitment
+  custodyCommitment: hash32;
+  // BLS proof of possession (a BLS signature)
+  proofOfPossession: Uint8Array[];
 }
 
 export interface Exit {

beaconChain/interfaces/state.ts

@@ -11,24 +11,25 @@ type uint384 = number;
 type hash32 = Uint8Array;
 
 export interface BeaconState {
+  // Misc
   slot: uint64;
   genesisTime: uint64;
-  // For versioning hard forks
-  forkData: ForkData;
+  forkData: ForkData; // For versioning hard forks
 
   // Validator registry
   validatorRegistry: ValidatorRecord[];
+  validatorBalances: uint64[];
   validatorRegistryLatestChangeSlot: uint64;
   validatorRegistryExitCount: uint64;
-  // For light clients to track deltas
-  validatorRegistryDeltaChainTip: hash32;
+  validatorRegistryDeltaChainTip: hash32; // For light clients to track deltas
 
   // Randomness and committees
-  randaoMix: hash32;
-  nextSeed: hash32;
+  latestRandaoMixes: hash32[];
+  latestVdfOutputs: hash32[];
   shardCommitteesAtSlots: ShardCommittee[][];
-  persistentCommittees: uint24[][];
-  persistentCommitteeReassignments: ShardReassignmentRecord[];
+
+  // Custody Challenges
+  custodyChallenges: CustodyChallenge[];
 
   // Finality
   previousJustifiedSlot: uint64;
@@ -38,11 +39,10 @@ export interface BeaconState {
 
   // Recent state
   latestCrosslinks: CrosslinkRecord[];
-  // Needed to process attestations; older to newer
-  latestBlockHashes: hash32[];
-  // Balances penalized at every withdrawal period
-  latestPenalizedExitBalances: uint64[];
+  latestBlockRoots: hash32[]; // Needed to process attestations; older to newer
+  latestPenalizedExitBalances: uint64[]; // Balances penalized at every withdrawal period
   latestAttestations: PendingAttestationRecord[];
+  batchedBlockRoots: hash32[];
 
   // PoW receipt root
   processedPowReceiptRoot: hash32;
@@ -56,16 +56,20 @@ export interface ValidatorRecord {
   withdrawalCredentials: hash32;
   // RANDAO commitment
   randaoCommitment: hash32;
-  // Slot the proposer has skipped (ie. layers of RANDAO expected)
-  randaoSkips: uint64;
-  // Balance in Gwei
-  balance: uint64;
+  // Slots the proposer has skipped (i.e. layers of RANDAO expected)
+  randaoLayers: uint64;
   // Status code
   status: uint64;
   // Slot when validator last changed status (or 0)
-  lastStatusChangeSlot: uint64;
+  latestStatusChangeSlot: uint64;
   // Exit counter when validator exited (or 0)
   exitCount: uint64;
+  // Custody Commitment
+  custodyCommitment: hash32;
+  // Slot of latest custody reseed
+  latestCustodyReseedSlot: uint64;
+  // Slotof second-latest custody reseed
+  penultimateCustodyResseedSlot: uint64;
 }
 
 export interface CrosslinkRecord {
@@ -118,3 +122,9 @@ export interface ForkData {
   // Fork slot number
   forkSlot: uint64;
 }
+
+/* tslint:disable:no-empty-interface*/
+// Empty for Phase 0
+export interface CustodyReseed {}
+export interface CustodyChallenge {}
+export interface CustodyResponse {}