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Merge pull request #393 from artemii235/mm2-kmd-interest
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#382 automatically claim interest when KMD transaction is created.
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@artemii235
artemii235 committed May 2, 2019
2 parents 2633293 + f8db61e commit 400758e
Showing 1 changed file with 91 additions and 14 deletions.
105 changes: 91 additions & 14 deletions mm2src/coins/utxo.rs
View file
Expand Up @@ -26,6 +26,7 @@ use byteorder::{LittleEndian, WriteBytesExt};
use chain::{TransactionOutput, TransactionInput, OutPoint};
use chain::constants::{SEQUENCE_FINAL};
use common::{dstr, lp, MutexGuardWrapper};
use common::custom_futures::join_all_sequential;
use common::mm_ctx::MmArc;
use futures::{Future};
use gstuff::{now_ms};
Expand Down Expand Up @@ -306,11 +307,11 @@ fn p2sh_spending_tx(
key_pair: &KeyPair,
version: i32,
overwintered: bool,
lock_time: u32,
sequence: u32,
version_group_id: u32,
zcash: bool,
) -> Result<UtxoTx, String> {
let lock_time = (now_ms() / 1000) as u32;
let unsigned = TransactionInputSigner {
lock_time,
version,
Expand Down Expand Up @@ -416,7 +417,7 @@ lazy_static! {static ref UTXO_LOCK: Mutex<()> = Mutex::new(());}
macro_rules! true_or_err {
($cond: expr, $msg: expr $(, $args:ident)*) => {
if !$cond {
return ERR!($msg $(, $args)*);
return Box::new(futures::future::err(ERRL!($msg $(, $args)*)));
}
};
}
Expand All @@ -430,7 +431,6 @@ impl UtxoCoin {
arc.generate_transaction(
unspents,
outputs,
0,
).and_then(move |(unsigned, _)| -> TransactionFut {
let prev_script = Builder::build_p2pkh(&arc.my_address.hash);
let signed = try_fus!(sign_tx(unsigned, &arc.key_pair, prev_script));
Expand Down Expand Up @@ -502,11 +502,11 @@ impl UtxoCoin {
&self,
utxos: Vec<UnspentInfo>,
mut outputs: Vec<TransactionOutput>,
lock_time: u32,
) -> Box<Future<Item=(TransactionInputSigner, AdditionalTxData), Error=String> + Send> {
let lock_time = (now_ms() / 1000) as u32;
let change_script_pubkey = Builder::build_p2pkh(&self.my_address.hash).to_bytes();
let arc = self.clone();
Box::new(self.get_tx_fee().and_then(move |mut tx_fee| {
Box::new(self.get_tx_fee().and_then(move |mut tx_fee| -> Box<Future<Item=(TransactionInputSigner, AdditionalTxData), Error=String> + Send> {
true_or_err!(!utxos.is_empty(), "Couldn't generate tx from empty utxos set");
true_or_err!(!outputs.is_empty(), "Couldn't generate tx from empty outputs set");

Expand Down Expand Up @@ -543,7 +543,7 @@ impl UtxoCoin {
outputs.push({
TransactionOutput {
value: change,
script_pubkey: change_script_pubkey
script_pubkey: change_script_pubkey.clone()
}
});
received_by_me += change;
Expand Down Expand Up @@ -571,7 +571,54 @@ impl UtxoCoin {
received_by_me,
spent_by_me: value_to_spend,
};
Ok((tx, data))
arc.calc_interest_if_required(tx, data, change_script_pubkey)
}))
}

/// Calculates interest if the coin is KMD
/// Adds the value to existing output to my_script_pub or creates additional interest output
/// returns transaction and data as is if the coin is not KMD
fn calc_interest_if_required(
&self,
mut unsigned: TransactionInputSigner,
mut data: AdditionalTxData,
my_script_pub: Bytes,
) -> Box<Future<Item=(TransactionInputSigner, AdditionalTxData), Error=String> + Send> {
if self.ticker != "KMD" {
return Box::new(futures::future::ok((unsigned, data)));
}
unsigned.lock_time = (now_ms() / 1000) as u32 - 777;
let prev_tx_futures: Vec<_> = unsigned.inputs
.iter()
.map(|input| self.rpc_client.get_verbose_transaction(input.previous_output.hash.reversed().into()))
.collect();

Box::new(join_all_sequential(prev_tx_futures).map(move |prev_transactions| {
let mut interest = 0;
let inputs_and_tx = unsigned.inputs.iter().zip(prev_transactions.iter());
inputs_and_tx.for_each(|(input, tx)| {
interest += kmd_interest(tx.height, input.amount, tx.locktime as u64, unsigned.lock_time as u64);
});
if interest > 0 {
data.received_by_me += interest;
let mut output_to_me = unsigned.outputs.iter_mut().find(|out| out.script_pubkey == my_script_pub);
// add calculated interest to existing output to my address
// or create the new one if it's not found
match output_to_me {
Some(ref mut output) => output.value += interest,
None => {
let interest_output = TransactionOutput {
script_pubkey: my_script_pub,
value: interest,
};
unsigned.outputs.push(interest_output);
}
};
} else {
// if interest is zero attempt to set the lowest possible lock_time to claim it later
unsigned.lock_time = (now_ms() / 1000) as u32 - 3000;
}
(unsigned, data)
}))
}
}
Expand Down Expand Up @@ -679,7 +726,6 @@ impl SwapOps for UtxoCoin {
&arc.key_pair,
arc.tx_version,
arc.overwintered,
(now_ms() / 1000) as u32,
SEQUENCE_FINAL,
arc.version_group_id,
arc.zcash,
Expand Down Expand Up @@ -719,7 +765,6 @@ impl SwapOps for UtxoCoin {
&arc.key_pair,
arc.tx_version,
arc.overwintered,
(now_ms() / 1000) as u32,
SEQUENCE_FINAL,
arc.version_group_id,
arc.zcash,
Expand Down Expand Up @@ -758,7 +803,6 @@ impl SwapOps for UtxoCoin {
&arc.key_pair,
arc.tx_version,
arc.overwintered,
(now_ms() / 1000) as u32,
SEQUENCE_FINAL - 1,
arc.version_group_id,
arc.zcash,
Expand Down Expand Up @@ -800,7 +844,6 @@ impl SwapOps for UtxoCoin {
&arc.key_pair,
arc.tx_version,
arc.overwintered,
(now_ms() / 1000) as u32,
SEQUENCE_FINAL - 1,
arc.version_group_id,
arc.zcash,
Expand Down Expand Up @@ -975,7 +1018,6 @@ impl MmCoin for UtxoCoin {
arc.generate_transaction(
unspents,
outputs,
0,
).and_then(move |(unsigned, data)| {
drop(utxo_lock);
let prev_script = Builder::build_p2pkh(&arc.my_address.hash);
Expand Down Expand Up @@ -1318,6 +1360,31 @@ pub fn utxo_coin_from_iguana_info(
Ok(UtxoCoin(Arc::new(coin)).into())
}

/// Function calculating KMD interest
/// https://komodoplatform.atlassian.net/wiki/spaces/KPSD/pages/71729215/What+is+the+5+Komodo+Stake+Reward
/// https://github.com/KomodoPlatform/komodo/blob/master/src/komodo_interest.h
fn kmd_interest(height: u64, value: u64, lock_time: u64, current_time: u64) -> u64 {
const KOMODO_ENDOFERA: u64 = 7777777;
const LOCKTIME_THRESHOLD: u64 = 500000000;
// interest will stop accrue after block 7777777
if height >= KOMODO_ENDOFERA { return 0 };
// interest doesn't accrue for lock_time < 500000000
if lock_time < LOCKTIME_THRESHOLD { return 0; }
// current time must be greater than tx lock_time
if current_time < lock_time { return 0; }

let mut minutes = (current_time - lock_time) / 60;
// at least 1 hour should pass
if minutes < 60 { return 0; }
// interest stop accruing after 1 year before block 1000000
if minutes > 365 * 24 * 60 { minutes = 365 * 24 * 60 };
// interest stop accruing after 1 month past 1000000 block
if height >= 1000000 && minutes > 31 * 24 * 60 { minutes = 31 * 24 * 60; }
// next 2 lines ported as is from Komodo codebase
minutes -= 59;
(value / 10512000) * minutes
}

#[cfg(test)]
mod tests {
use super::*;
Expand Down Expand Up @@ -1386,7 +1453,7 @@ mod tests {
value: 999,
}];

let generated = coin.generate_transaction(unspents, outputs, 0).wait();
let generated = coin.generate_transaction(unspents, outputs).wait();
// must not allow to use output with value < tx_fee
unwrap_err!(generated);

Expand All @@ -1400,7 +1467,7 @@ mod tests {
value: 98001,
}];

let generated = unwrap!(coin.generate_transaction(unspents, outputs, 0).wait());
let generated = unwrap!(coin.generate_transaction(unspents, outputs).wait());
// the change that is less than tx_fee must be included to miner fee according to JL777
// so no extra outputs should appear in generated transaction
assert_eq!(generated.0.outputs.len(), 1);
Expand All @@ -1425,4 +1492,14 @@ mod tests {
let actual_addr = unwrap!(coin.addresses_from_script(&script));
assert_eq!(expected_addr, actual_addr);
}

#[test]
fn test_kmd_interest() {
let value = 64605500822;
let lock_time = 1556623906;
let current_time = 1556623906 + 3600 + 300;
let expected = 36870;
let actual = kmd_interest(1000001, value, lock_time, current_time);
assert_eq!(expected, actual);
}
}

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