Delete unused validator_change crate (#569)

Hopefully for the last time...

eth2/validator_change/Cargo.toml

@@ -1,11 +0,0 @@
-[package]
-name = "validator_change"
-version = "0.1.0"
-authors = ["Paul Hauner <paul@paulhauner.com>"]
-edition = "2018"
-
-[dependencies]
-bytes = "0.4.10"
-eth2_hashing = { path = "../utils/eth2_hashing" }
-eth2_ssz = "0.1"
-types = { path = "../types" }

eth2/validator_change/src/lib.rs

@@ -1,142 +0,0 @@
-extern crate bytes;
-extern crate hashing;
-extern crate types;
-
-use bytes::{BufMut, BytesMut};
-use eth2_hashing::canonical_hash;
-use ssz::ssz_encode;
-use std::cmp::max;
-use types::{Hash256, ValidatorRecord, ValidatorStatus};
-
-pub enum UpdateValidatorSetError {
-    ArithmeticOverflow,
-}
-
-const VALIDATOR_FLAG_ENTRY: u8 = 0;
-const VALIDATOR_FLAG_EXIT: u8 = 1;
-
-pub fn update_validator_set(
-    validators: &mut Vec<ValidatorRecord>,
-    hash_chain: Hash256,
-    present_slot: u64,
-    deposit_size_gwei: u64,
-    max_validator_churn_quotient: u64,
-) -> Result<(), UpdateValidatorSetError> {
-    /*
-     * Total balance of all active validators.
-     *
-     * Return an error if an overflow occurs.
-     */
-    let total_balance = {
-        let mut bal: u64 = 0;
-        for v in validators.iter() {
-            if v.status_is(ValidatorStatus::Active) {
-                bal = bal
-                    .checked_add(v.balance)
-                    .ok_or(UpdateValidatorSetError::ArithmeticOverflow)?;
-            }
-        }
-        bal
-    };
-
-    /*
-     * Note: this is not the maximum allowable change, it can actually be higher.
-     */
-    let max_allowable_change = {
-        let double_deposit_size = deposit_size_gwei
-            .checked_mul(2)
-            .ok_or(UpdateValidatorSetError::ArithmeticOverflow)?;
-        max(
-            double_deposit_size,
-            total_balance / max_validator_churn_quotient,
-        )
-    };
-
-    let mut hasher = ValidatorChangeHashChain {
-        bytes: hash_chain.to_vec(),
-    };
-    let mut total_changed: u64 = 0;
-    for (i, v) in validators.iter_mut().enumerate() {
-        match v.status {
-            /*
-             * Validator is pending activation.
-             */
-            ValidatorStatus::PendingActivation => {
-                let new_total_changed = total_changed
-                    .checked_add(deposit_size_gwei)
-                    .ok_or(UpdateValidatorSetError::ArithmeticOverflow)?;
-                /*
-                 * If entering this validator would not exceed the max balance delta,
-                 * activate the validator.
-                 */
-                if new_total_changed <= max_allowable_change {
-                    v.status = ValidatorStatus::Active;
-                    hasher.extend(i, &ssz_encode(&v.pubkey), VALIDATOR_FLAG_ENTRY);
-                    total_changed = new_total_changed;
-                } else {
-                    // Entering the validator would exceed the balance delta.
-                    break;
-                }
-            }
-            /*
-             * Validator is pending exit.
-             */
-            ValidatorStatus::PendingExit => {
-                let new_total_changed = total_changed
-                    .checked_add(v.balance)
-                    .ok_or(UpdateValidatorSetError::ArithmeticOverflow)?;
-                /*
-                 * If exiting this validator would not exceed the max balance delta,
-                 * exit the validator
-                 */
-                if new_total_changed <= max_allowable_change {
-                    v.status = ValidatorStatus::PendingWithdraw;
-                    v.exit_slot = present_slot;
-                    hasher.extend(i, &ssz_encode(&v.pubkey), VALIDATOR_FLAG_EXIT);
-                    total_changed = new_total_changed;
-                } else {
-                    // Exiting the validator would exceed the balance delta.
-                    break;
-                }
-            }
-            _ => (),
-        };
-        if total_changed >= max_allowable_change {
-            break;
-        }
-    }
-    Ok(())
-}
-
-pub struct ValidatorChangeHashChain {
-    bytes: Vec<u8>,
-}
-
-impl ValidatorChangeHashChain {
-    pub fn extend(&mut self, index: usize, pubkey: &Vec<u8>, flag: u8) {
-        let mut message = self.bytes.clone();
-        message.append(&mut serialize_validator_change_record(index, pubkey, flag));
-        self.bytes = canonical_hash(&message);
-    }
-}
-
-fn serialize_validator_change_record(index: usize, pubkey: &Vec<u8>, flag: u8) -> Vec<u8> {
-    let mut buf = BytesMut::with_capacity(68);
-    buf.put_u8(flag);
-    let index_bytes = {
-        let mut buf = BytesMut::with_capacity(8);
-        buf.put_u64_be(index as u64);
-        buf.take()[8 - 3..8].to_vec()
-    };
-    buf.put(index_bytes);
-    buf.put(pubkey);
-    buf.take().to_vec()
-}
-
-#[cfg(test)]
-mod tests {
-    #[test]
-    fn it_works() {
-        assert_eq!(2 + 2, 4);
-    }
-}