simple market maker bot

mm2src/coins/lp_coins.rs

@@ -31,7 +31,7 @@
 #[macro_use] extern crate ser_error_derive;
 
 use async_trait::async_trait;
-use bigdecimal::{BigDecimal, ParseBigDecimalError};
+use bigdecimal::{BigDecimal, ParseBigDecimalError, Zero};
 use common::executor::{spawn, Timer};
 use common::mm_ctx::{from_ctx, MmArc, MmWeak};
 use common::mm_error::prelude::*;
@@ -124,6 +124,7 @@ cfg_wasm32! {
 
 pub type BalanceResult<T> = Result<T, MmError<BalanceError>>;
 pub type BalanceFut<T> = Box<dyn Future<Item = T, Error = MmError<BalanceError>> + Send>;
+pub type NonZeroBalanceFut<T> = Box<dyn Future<Item = T, Error = MmError<GetNonZeroBalance>> + Send>;
 pub type NumConversResult<T> = Result<T, MmError<NumConversError>>;
 pub type WithdrawResult = Result<TransactionDetails, MmError<WithdrawError>>;
 pub type WithdrawFut = Box<dyn Future<Item = TransactionDetails, Error = MmError<WithdrawError>> + Send>;
@@ -344,6 +345,16 @@ pub trait MarketCoinOps {
 
     fn my_address(&self) -> Result<String, String>;
 
+    fn get_non_zero_balance(&self) -> NonZeroBalanceFut<MmNumber> {
+        let closure = |spendable: BigDecimal| {
+            if spendable.is_zero() {
+                return MmError::err(GetNonZeroBalance::BalanceIsZero);
+            }
+            Ok(MmNumber::from(spendable))
+        };
+        Box::new(self.my_spendable_balance().map_err(From::from).and_then(closure))
+    }
+
     fn my_balance(&self) -> BalanceFut<CoinBalance>;
 
     fn my_spendable_balance(&self) -> BalanceFut<BigDecimal> {
@@ -698,6 +709,18 @@ pub enum BalanceError {
     Internal(String),
 }
 
+#[derive(Debug, PartialEq, Display)]
+pub enum GetNonZeroBalance {
+    #[display(fmt = "Internal error when retrieving balance - skipping")]
+    MyBalanceError(BalanceError),
+    #[display(fmt = "Balance is zero - skipping")]
+    BalanceIsZero,
+}
+
+impl From<BalanceError> for GetNonZeroBalance {
+    fn from(e: BalanceError) -> Self { GetNonZeroBalance::MyBalanceError(e) }
+}
+
 impl From<NumConversError> for BalanceError {
     fn from(e: NumConversError) -> Self { BalanceError::Internal(e.to_string()) }
 }

mm2src/common/log.rs

@@ -238,6 +238,8 @@ pub trait LogOnError {
 
     // Log the error, caller location and the given message to ERROR level here.
     fn error_log_with_msg(self, msg: &str);
+
+    fn error_log_passthrough(self) -> Self;
 }
 
 impl<T, E: fmt::Display> LogOnError for Result<T, E> {
@@ -280,6 +282,17 @@ impl<T, E: fmt::Display> LogOnError for Result<T, E> {
             error!("{}:{}] {}: {}", file, line, msg, e);
         }
     }
+
+    #[track_caller]
+    fn error_log_passthrough(self) -> Self {
+        if let Err(e) = &self {
+            let location = std::panic::Location::caller();
+            let file = gstuff::filename(location.file());
+            let line = location.line();
+            error!("{}:{}] {}", file, line, e);
+        }
+        self
+    }
 }
 
 pub trait TagParam<'a> {

mm2src/common/mm_ctx.rs

@@ -76,6 +76,7 @@ pub struct MmCtx {
     pub stop_listeners: Mutex<Vec<StopListenerCallback>>,
     /// The context belonging to the `ordermatch` mod: `OrdermatchContext`.
     pub ordermatch_ctx: Mutex<Option<Arc<dyn Any + 'static + Send + Sync>>>,
+    pub simple_market_maker_bot_ctx: Mutex<Option<Arc<dyn Any + 'static + Send + Sync>>>,
     pub p2p_ctx: Mutex<Option<Arc<dyn Any + 'static + Send + Sync>>>,
     pub peer_id: Constructible<String>,
     /// The context belonging to the `coins` crate: `CoinsContext`.
@@ -111,6 +112,7 @@ impl MmCtx {
             ffi_handle: Constructible::default(),
             stop_listeners: Mutex::new(Vec::new()),
             ordermatch_ctx: Mutex::new(None),
+            simple_market_maker_bot_ctx: Mutex::new(None),
             p2p_ctx: Mutex::new(None),
             peer_id: Constructible::default(),
             coins_ctx: Mutex::new(None),