Feat staker v2 no fp and subpointers

.gitignore

@@ -1,3 +1,7 @@
+.env
+.vscode
+.starkli
+.DS_Store
 #######
 Scarb
 #######

src/lib.cairo

@@ -16,6 +16,10 @@ pub mod governor;
 mod governor_test;
 
 pub mod staker;
+
+pub mod staker_log;
+#[cfg(test)]
+pub mod staker_log_test;
 #[cfg(test)]
 mod staker_test;
 

src/staker.cairo

@@ -52,22 +52,28 @@ pub trait IStaker<TContractState> {
     fn get_average_delegated_over_last(
         self: @TContractState, delegate: ContractAddress, period: u64,
     ) -> u128;
+
+    // Gets the cumulative staked amount * per second staked for the given timestamp and account.
+    fn get_cumulative_seconds_per_total_staked_at(self: @TContractState, timestamp: u64) -> u256;
 }
 
 #[starknet::contract]
 pub mod Staker {
+    use core::integer::{u512, u512_safe_div_rem_by_u256};
     use core::num::traits::zero::{Zero};
+    use crate::staker_log::{LogOperations, MAX_FP, StakingLog};
     use governance::interfaces::erc20::{IERC20Dispatcher, IERC20DispatcherTrait};
+    use starknet::storage::VecTrait;
     use starknet::storage::{
         Map, StorageMapReadAccess, StorageMapWriteAccess, StoragePathEntry,
         StoragePointerReadAccess, StoragePointerWriteAccess,
     };
+
     use starknet::{
-        get_block_timestamp, get_caller_address, get_contract_address,
+        ContractAddress, get_block_timestamp, get_caller_address, get_contract_address,
         storage_access::{StorePacking},
     };
-    use super::{ContractAddress, IStaker};
-
+    use super::{IStaker};
 
     #[derive(Copy, Drop, PartialEq, Debug)]
     pub struct DelegatedSnapshot {
@@ -78,6 +84,7 @@ pub mod Staker {
     const TWO_POW_64: u128 = 0x10000000000000000;
     const TWO_POW_192: u256 = 0x1000000000000000000000000000000000000000000000000;
     const TWO_POW_192_DIVISOR: NonZero<u256> = 0x1000000000000000000000000000000000000000000000000;
+    const TWO_POW_127: u128 = 0x80000000000000000000000000000000_u128;
 
     pub(crate) impl DelegatedSnapshotStorePacking of StorePacking<DelegatedSnapshot, felt252> {
         fn pack(value: DelegatedSnapshot) -> felt252 {
@@ -104,6 +111,8 @@ pub mod Staker {
         amount_delegated: Map<ContractAddress, u128>,
         delegated_cumulative_num_snapshots: Map<ContractAddress, u64>,
         delegated_cumulative_snapshot: Map<ContractAddress, Map<u64, DelegatedSnapshot>>,
+        total_staked: u128,
+        staking_log: StakingLog,
     }
 
     #[constructor]
@@ -253,6 +262,12 @@ pub mod Staker {
             self
                 .amount_delegated
                 .write(delegate, self.insert_snapshot(delegate, get_block_timestamp()) + amount);
+
+            let total_staked = self.total_staked.read();
+
+            self.total_staked.write(total_staked + amount);
+            self.staking_log.log_change(amount, total_staked);
+
             self.emit(Staked { from, delegate, amount });
         }
 
@@ -280,6 +295,11 @@ pub mod Staker {
                 .amount_delegated
                 .write(delegate, self.insert_snapshot(delegate, get_block_timestamp()) - amount);
             assert(self.token.read().transfer(recipient, amount.into()), 'TRANSFER_FAILED');
+
+            let total_staked = self.total_staked.read();
+            self.total_staked.write(total_staked - amount);
+            self.staking_log.log_change(amount, total_staked);
+
             self.emit(Withdrawn { from, delegate, to: recipient, amount });
         }
 
@@ -333,5 +353,67 @@ pub mod Staker {
             let now = get_block_timestamp();
             self.get_average_delegated(delegate, now - period, now)
         }
+
+        fn get_cumulative_seconds_per_total_staked_at(
+            self: @ContractState, timestamp: u64,
+        ) -> u256 {
+            if let Option::Some((log_record, idx)) = self
+                .staking_log
+                .find_in_change_log(timestamp) {
+                let total_staked = if (idx == self.staking_log.len() - 1) {
+                    // if last rescord found
+                    self.total_staked.read()
+                } else {
+                    // otherwise calculate using cumulative_seconds_per_total_staked difference
+                    let next_log_record = self.staking_log.at(idx + 1).read();
+
+                    // substract fixed point values
+                    let divisor = next_log_record.cumulative_seconds_per_total_staked
+                        - log_record.cumulative_seconds_per_total_staked;
+
+                    if divisor.is_zero() {
+                        return 0_u64.into();
+                    }
+
+                    let diff_seconds: u128 = (next_log_record.timestamp - log_record.timestamp)
+                        .into();
+
+                    // Divide u64 by fixed point
+                    let (total_staked_fp_medium, _) = u512_safe_div_rem_by_u256(
+                        u512 { limb0: 0, limb1: 0, limb2: 0, limb3: diff_seconds },
+                        divisor.try_into().unwrap(),
+                    );
+
+                    let total_staked_fp = u256 {
+                        low: total_staked_fp_medium.limb1, high: total_staked_fp_medium.limb2,
+                    };
+
+                    assert(total_staked_fp.high < MAX_FP, 'FP_OVERFLOW');
+
+                    // round value
+                    total_staked_fp.high + if (total_staked_fp.low >= TWO_POW_127) {
+                        1
+                    } else {
+                        0
+                    }
+                };
+
+                let seconds_diff = timestamp - log_record.timestamp;
+
+                let staked_seconds: u256 = if total_staked == 0 {
+                    0_u256
+                } else {
+                    // Divide u64 by u128
+                    u256 { low: 0, high: seconds_diff.into() } / total_staked.into()
+                };
+
+                // Sum fixed posits
+                let result = log_record.cumulative_seconds_per_total_staked + staked_seconds;
+                assert(result.high < MAX_FP, 'FP_OVERFLOW');
+                return result;
+            }
+
+            return 0_u256;
+        }
     }
 }

src/staker_log.cairo

@@ -0,0 +1,178 @@
+use starknet::storage::MutableVecTrait;
+use starknet::storage::{
+    Mutable, StorageAsPath, StorageBase, StoragePointerReadAccess, StoragePointerWriteAccess,
+};
+
+use starknet::storage::{Vec, VecTrait};
+use starknet::storage_access::{StorePacking};
+use starknet::{get_block_timestamp};
+
+pub type StakingLog = Vec<StakingLogRecord>;
+
+const TWO_POW_32: u64 = 0x100000000_u64;
+const MASK_32_BITS: u128 = 0x100000000_u128 - 1;
+const TWO_POW_160: u256 = 0x10000000000000000000000000000000000000000;
+pub const MAX_FP: u128 = 0x8000000000000110000000000000000_u128;
+
+#[derive(Drop, Serde, Copy)]
+pub(crate) struct StakingLogRecord {
+    pub(crate) timestamp: u64,
+    // Only 128+32=160 bits are used
+    pub(crate) cumulative_total_staked: u256,
+    pub(crate) cumulative_seconds_per_total_staked: u256,
+}
+
+#[generate_trait]
+pub impl StakingLogOperations of LogOperations {
+    fn get_total_staked(self: @StorageBase<StakingLog>, timestamp: u64) -> Option<u128> {
+        Option::Some(0)
+    }
+
+    fn find_in_change_log(
+        self: @StorageBase<StakingLog>, timestamp: u64,
+    ) -> Option<(StakingLogRecord, u64)> {
+        let log = self.as_path();
+        if log.len() == 0 {
+            return Option::None;
+        }
+        let mut left = 0;
+        let mut right = log.len() - 1;
+
+        // To avoid reading from the storage multiple times.
+        let mut result_ptr: Option<(StakingLogRecord, u64)> = Option::None;
+
+        while (left <= right) {
+            let center = (right + left) / 2;
+            let record_ptr = log.at(center);
+            let record = record_ptr.read();
+
+            if record.timestamp <= timestamp {
+                result_ptr = Option::Some((record, center));
+                left = center + 1;
+            } else {
+                right = center - 1;
+            };
+        };
+
+        if let Option::Some((result, idx)) = result_ptr {
+            return Option::Some((result, idx));
+        }
+
+        return Option::None;
+    }
+
+    fn log_change(self: StorageBase<Mutable<StakingLog>>, amount: u128, total_staked: u128) {
+        let log = self.as_path();
+
+        let block_timestamp = get_block_timestamp();
+
+        if log.len() == 0 {
+            log
+                .append()
+                .write(
+                    StakingLogRecord {
+                        timestamp: block_timestamp,
+                        cumulative_total_staked: 0_u256,
+                        cumulative_seconds_per_total_staked: 0_u64.into(),
+                    },
+                );
+
+            return;
+        }
+
+        let last_record_ptr = log.at(log.len() - 1);
+
+        let mut last_record = last_record_ptr.read();
+
+        let mut record = if last_record.timestamp == block_timestamp {
+            // update record
+            last_record_ptr
+        } else {
+            // create new record
+            log.append()
+        };
+
+        // Might be zero
+        let seconds_diff = block_timestamp - last_record.timestamp;
+
+        let total_staked_by_elapsed_seconds = total_staked.into() * seconds_diff.into();
+
+        let staked_seconds_per_total_staked: u256 = if total_staked == 0 {
+            0_u64.into()
+        } else {
+            let res = u256 { low: 0, high: seconds_diff.into() } / total_staked.into();
+            assert(res.high < MAX_FP, 'FP_OVERFLOW');
+            res
+        };
+
+        // Add a new record.
+        record
+            .write(
+                StakingLogRecord {
+                    timestamp: block_timestamp,
+                    cumulative_total_staked: last_record.cumulative_total_staked
+                        + total_staked_by_elapsed_seconds,
+                    cumulative_seconds_per_total_staked: last_record
+                        .cumulative_seconds_per_total_staked
+                        + staked_seconds_per_total_staked,
+                },
+            );
+    }
+}
+
+//
+// Storage layout for StakingLogRecord
+//
+
+pub(crate) impl StakingLogRecordStorePacking of StorePacking<StakingLogRecord, (felt252, felt252)> {
+    fn pack(value: StakingLogRecord) -> (felt252, felt252) {
+        let packed_ts_cumulative_total_staked: felt252 = pack_u64_u256_tuple(
+            value.timestamp, value.cumulative_total_staked,
+        );
+
+        let cumulative_seconds_per_total_staked: felt252 = value
+            .cumulative_seconds_per_total_staked
+            .try_into()
+            .unwrap();
+
+        (packed_ts_cumulative_total_staked, cumulative_seconds_per_total_staked)
+    }
+
+    fn unpack(value: (felt252, felt252)) -> StakingLogRecord {
+        let (packed_ts_cumulative_total_staked, cumulative_seconds_per_total_staked) = value;
+        let (timestamp, cumulative_total_staked) = unpack_u64_u256_tuple(
+            packed_ts_cumulative_total_staked,
+        );
+
+        StakingLogRecord {
+            timestamp: timestamp,
+            cumulative_total_staked: cumulative_total_staked,
+            cumulative_seconds_per_total_staked: cumulative_seconds_per_total_staked
+                .try_into()
+                .unwrap(),
+        }
+    }
+}
+
+pub(crate) fn pack_u64_u256_tuple(val1: u64, val2: u256) -> felt252 {
+    let cumulative_total_staked_high_32_bits: u128 = val2.high & MASK_32_BITS;
+    u256 {
+        high: val1.into() * TWO_POW_32.into() + cumulative_total_staked_high_32_bits.into(),
+        low: val2.low,
+    }
+        .try_into()
+        .unwrap()
+}
+
+pub(crate) fn unpack_u64_u256_tuple(value: felt252) -> (u64, u256) {
+    let packed_ts_total_staked_u256: u256 = value.into();
+
+    let cumulative_total_staked = u256 {
+        high: packed_ts_total_staked_u256.high & MASK_32_BITS, low: packed_ts_total_staked_u256.low,
+    };
+
+    return (
+        (packed_ts_total_staked_u256.high / TWO_POW_32.into()).try_into().unwrap(),
+        cumulative_total_staked,
+    );
+}

src/staker_log_test.cairo

@@ -0,0 +1,33 @@
+use crate::staker_log::{pack_u64_u256_tuple, unpack_u64_u256_tuple};
+
+const MASK_32_BITS: u128 = 0x100000000_u128 - 1;
+const MASK_64_BITS: u128 = 0x10000000000000000_u128 - 1;
+const MASK_160_BITS: u256 = 0x10000000000000000000000000000000000000000 - 1;
+
+
+fn assert_packs_and_unpacks(timestamp: u64, total_staked: u256) {
+    let packed: u256 = pack_u64_u256_tuple(timestamp, total_staked).into();
+
+    let first_160_bits: u256 = packed & MASK_160_BITS;
+
+    let shifted_160_bits_right: u128 = packed.high / (MASK_32_BITS + 1);
+
+    let last_64_bits: u64 = (shifted_160_bits_right & MASK_64_BITS).try_into().unwrap();
+    assert_eq!(first_160_bits, total_staked);
+    assert_eq!(last_64_bits, timestamp);
+
+    let (unpacked_timestamp, unpacked_cumulative_total_staked) = unpack_u64_u256_tuple(
+        packed.try_into().unwrap(),
+    );
+    assert_eq!(unpacked_timestamp, timestamp);
+    assert_eq!(unpacked_cumulative_total_staked, total_staked);
+}
+
+#[test]
+fn test_staking_log_packing() {
+    assert_packs_and_unpacks(0_u64, 0_u256);
+    assert_packs_and_unpacks(10_u64, 50_u256);
+    assert_packs_and_unpacks(
+        0xffffffffffffffff_u64, 0xffffffffffffffffffffffffffffffffffffffff_u256,
+    )
+}