fix: replace FilterStream with concrete type (#69)

* fix: replace FilterStream with concrete type

* fix: use PinBoxFut type alias

* ci: fix CI error with ledger

ethers-contract/src/event.rs

@@ -1,6 +1,6 @@
 use crate::ContractError;
 
-use ethers_providers::{FilterStream, JsonRpcClient, Provider};
+use ethers_providers::{JsonRpcClient, Provider};
 
 use ethers_core::{
     abi::{Detokenize, Event as AbiEvent, RawLog},

ethers-providers/src/lib.rs

@@ -113,17 +113,19 @@ mod pending_transaction;
 pub use pending_transaction::PendingTransaction;
 
 mod stream;
-pub use stream::{FilterStream, DEFAULT_POLL_INTERVAL};
-// re-export `StreamExt` so that consumers can call `next()` on the `FilterStream`
-// without having to import futures themselves
 pub use futures_util::StreamExt;
+pub use stream::{FilterWatcher, DEFAULT_POLL_INTERVAL};
 
 use async_trait::async_trait;
 use serde::{Deserialize, Serialize};
-use std::{error::Error, fmt::Debug};
+use std::{error::Error, fmt::Debug, future::Future, pin::Pin};
 
 pub use provider::{Provider, ProviderError};
 
+// Helper type alias
+pub(crate) type PinBoxFut<'a, T> =
+    Pin<Box<dyn Future<Output = Result<T, ProviderError>> + 'a + Send>>;
+
 #[async_trait]
 /// Trait which must be implemented by data transports to be used with the Ethereum
 /// JSON-RPC provider.

ethers-providers/src/pending_transaction.rs

@@ -1,6 +1,6 @@
 use crate::{
     stream::{interval, DEFAULT_POLL_INTERVAL},
-    JsonRpcClient, Provider, ProviderError,
+    JsonRpcClient, PinBoxFut, Provider, ProviderError,
 };
 use ethers_core::types::{TransactionReceipt, TxHash, U64};
 use futures_core::stream::Stream;
@@ -168,9 +168,6 @@ impl<'a, P> Deref for PendingTransaction<'a, P> {
     }
 }
 
-// Helper type alias
-type PinBoxFut<'a, T> = Pin<Box<dyn Future<Output = Result<T, ProviderError>> + 'a + Send>>;
-
 // We box the TransactionReceipts to keep the enum small.
 enum PendingTxState<'a> {
     /// Waiting for interval to elapse before calling API again

ethers-providers/src/provider.rs

@@ -1,6 +1,6 @@
 use crate::{
     ens,
-    stream::{FilterStream, FilterWatcher, DEFAULT_POLL_INTERVAL},
+    stream::{FilterWatcher, DEFAULT_POLL_INTERVAL},
     Http as HttpProvider, JsonRpcClient, PendingTransaction,
 };
 
@@ -321,32 +321,26 @@ impl<P: JsonRpcClient> Provider<P> {
     }
 
     /// Streams matching filter logs
-    pub async fn watch(
-        &self,
-        filter: &Filter,
-    ) -> Result<impl FilterStream<Log> + '_, ProviderError> {
+    pub async fn watch(&self, filter: &Filter) -> Result<FilterWatcher<'_, P, Log>, ProviderError> {
         let id = self.new_filter(FilterKind::Logs(filter)).await?;
-        let fut = move || Box::pin(self.get_filter_changes(id));
-        let filter = FilterWatcher::new(id, fut).interval(self.get_interval());
+        let filter = FilterWatcher::new(id, self).interval(self.get_interval());
 
         Ok(filter)
     }
 
     /// Streams new block hashes
-    pub async fn watch_blocks(&self) -> Result<impl FilterStream<H256> + '_, ProviderError> {
+    pub async fn watch_blocks(&self) -> Result<FilterWatcher<'_, P, H256>, ProviderError> {
         let id = self.new_filter(FilterKind::NewBlocks).await?;
-        let fut = move || Box::pin(self.get_filter_changes(id));
-        let filter = FilterWatcher::new(id, fut).interval(self.get_interval());
+        let filter = FilterWatcher::new(id, self).interval(self.get_interval());
         Ok(filter)
     }
 
     /// Streams pending transactions
     pub async fn watch_pending_transactions(
         &self,
-    ) -> Result<impl FilterStream<H256> + '_, ProviderError> {
+    ) -> Result<FilterWatcher<'_, P, H256>, ProviderError> {
         let id = self.new_filter(FilterKind::PendingTransactions).await?;
-        let fut = move || Box::pin(self.get_filter_changes(id));
-        let filter = FilterWatcher::new(id, fut).interval(self.get_interval());
+        let filter = FilterWatcher::new(id, self).interval(self.get_interval());
         Ok(filter)
     }
 

ethers-providers/src/stream.rs

@@ -1,14 +1,13 @@
-use crate::ProviderError;
+use crate::{JsonRpcClient, PinBoxFut, Provider};
 
 use ethers_core::types::U256;
 
-use futures_core::{stream::Stream, TryFuture};
+use futures_core::stream::Stream;
 use futures_timer::Delay;
 use futures_util::{stream, FutureExt, StreamExt};
 use pin_project::pin_project;
 use serde::Deserialize;
 use std::{
-    future::Future,
     pin::Pin,
     task::{Context, Poll},
     time::Duration,
@@ -23,92 +22,66 @@ pub fn interval(duration: Duration) -> impl Stream<Item = ()> + Send + Unpin {
 /// The default polling interval for filters and pending transactions
 pub const DEFAULT_POLL_INTERVAL: Duration = Duration::from_millis(7000);
 
-/// Trait for streaming filters.
-pub trait FilterStream<R>: StreamExt + Stream<Item = R>
-where
-    R: for<'de> Deserialize<'de>,
-{
-    /// Returns the filter's ID for it to be uninstalled
-    fn id(&self) -> U256;
-
-    /// Sets the stream's polling interval
-    fn interval(self, duration: Duration) -> Self;
-
-    /// Alias for Box::pin, must be called in order to pin the stream and be able
-    /// to call `next` on it.
-    fn stream(self) -> Pin<Box<Self>>
-    where
-        Self: Sized,
-    {
-        Box::pin(self)
-    }
-}
-
-enum FilterWatcherState<F, R> {
+enum FilterWatcherState<'a, R> {
     WaitForInterval,
-    GetFilterChanges(F),
+    GetFilterChanges(PinBoxFut<'a, Vec<R>>),
     NextItem(IntoIter<R>),
 }
 
 #[must_use = "filters do nothing unless you stream them"]
 #[pin_project]
-pub(crate) struct FilterWatcher<F: FutureFactory, R> {
-    id: U256,
+pub struct FilterWatcher<'a, P, R> {
+    /// The filter's installed id on the ethereum node
+    pub id: U256,
 
-    #[pin]
-    // Future factory for generating new calls on each loop
-    factory: F,
+    provider: &'a Provider<P>,
 
     // The polling interval
     interval: Box<dyn Stream<Item = ()> + Send + Unpin>,
 
-    state: FilterWatcherState<F::FutureItem, R>,
+    state: FilterWatcherState<'a, R>,
 }
 
-impl<F, R> FilterWatcher<F, R>
+impl<'a, P, R> FilterWatcher<'a, P, R>
 where
-    F: FutureFactory,
+    P: JsonRpcClient,
     R: for<'de> Deserialize<'de>,
 {
     /// Creates a new watcher with the provided factory and filter id.
-    pub fn new<T: Into<U256>>(id: T, factory: F) -> Self {
+    pub fn new<T: Into<U256>>(id: T, provider: &'a Provider<P>) -> Self {
         Self {
             id: id.into(),
             interval: Box::new(interval(DEFAULT_POLL_INTERVAL)),
             state: FilterWatcherState::WaitForInterval,
-            factory,
-        }
+            provider,
         }
     }
 
-impl<F, R> FilterStream<R> for FilterWatcher<F, R>
-where
-    F: FutureFactory,
-    F::FutureItem: Future<Output = Result<Vec<R>, ProviderError>>,
-    R: for<'de> Deserialize<'de>,
-{
-    fn id(&self) -> U256 {
-        self.id
-    }
-
-    fn interval(mut self, duration: Duration) -> Self {
+    /// Sets the stream's polling interval
+    pub fn interval(mut self, duration: Duration) -> Self {
         self.interval = Box::new(interval(duration));
         self
     }
+
+    /// Alias for Box::pin, must be called in order to pin the stream and be able
+    /// to call `next` on it.
+    pub fn stream(self) -> Pin<Box<Self>> {
+        Box::pin(self)
+    }
 }
 
 // Pattern for flattening the returned Vec of filter changes taken from
 // https://github.com/tomusdrw/rust-web3/blob/f043b222744580bf4be043da757ab0b300c3b2da/src/api/eth_filter.rs#L50-L67
-impl<F, R> Stream for FilterWatcher<F, R>
+impl<'a, P, R> Stream for FilterWatcher<'a, P, R>
 where
-    F: FutureFactory,
-    F::FutureItem: Future<Output = Result<Vec<R>, ProviderError>>,
-    R: for<'de> Deserialize<'de>,
+    P: JsonRpcClient,
+    R: for<'de> Deserialize<'de> + 'a,
 {
     type Item = R;
 
-    fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
-        let mut this = self.project();
+    fn poll_next(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Option<Self::Item>> {
+        let this = self.project();
+        let id = *this.id;
 
         *this.state = match this.state {
             FilterWatcherState::WaitForInterval => {
@@ -117,14 +90,15 @@ where
 
                 // create a new instance of the future
                 cx.waker().wake_by_ref();
-                FilterWatcherState::GetFilterChanges(this.factory.as_mut().new())
+                let fut = Box::pin(this.provider.get_filter_changes(id));
+                FilterWatcherState::GetFilterChanges(fut)
             }
             FilterWatcherState::GetFilterChanges(fut) => {
                 // NOTE: If the provider returns an error, this will return an empty
                 // vector. Should we make this return a Result instead? Ideally if we're
                 // in a streamed loop we wouldn't want the loop to terminate if an error
                 // is encountered (since it might be a temporary error).
-                let items: Vec<R> = futures_util::ready!(fut.poll_unpin(cx)).unwrap_or_default();
+                let items: Vec<R> = futures_util::ready!(fut.as_mut().poll(cx)).unwrap_or_default();
                 cx.waker().wake_by_ref();
                 FilterWatcherState::NextItem(items.into_iter())
             }
@@ -144,66 +118,3 @@ where
         Poll::Pending
     }
 }
-
-// Do not leak private trait
-// Pattern for re-usable futures from: https://gitlab.com/Ploppz/futures-retry/-/blob/std-futures/src/future.rs#L13
-use factory::FutureFactory;
-mod factory {
-    use super::*;
-
-    /// A factory trait used to create futures.
-    ///
-    /// We need a factory for the stream logic because when (and if) a future
-    /// is polled to completion, it can't be polled again. Hence we need to
-    /// create a new one.
-    ///
-    /// This trait is implemented for any closure that returns a `Future`, so you don't
-    /// have to write your own type and implement it to handle some simple cases.
-    pub trait FutureFactory {
-        /// A future type that is created by the `new` method.
-        type FutureItem: TryFuture + Unpin;
-
-        /// Creates a new future. We don't need the factory to be immutable so we
-        /// pass `self` as a mutable reference.
-        fn new(self: Pin<&mut Self>) -> Self::FutureItem;
-    }
-
-    impl<T, F> FutureFactory for T
-    where
-        T: Unpin + FnMut() -> F,
-        F: TryFuture + Unpin,
-    {
-        type FutureItem = F;
-
-        #[allow(clippy::new_ret_no_self)]
-        fn new(self: Pin<&mut Self>) -> F {
-            (*self.get_mut())()
-        }
-    }
-}
-
-#[cfg(test)]
-mod watch {
-    use super::*;
-    use futures_util::StreamExt;
-
-    #[tokio::test]
-    async fn stream() {
-        let factory = || Box::pin(async { Ok::<Vec<u64>, ProviderError>(vec![1, 2, 3]) });
-        let filter = FilterWatcher::<_, u64>::new(1, factory);
-        // stream combinator calls are still doable since FilterStream extends
-        // Stream and StreamExt
-        let mut stream = filter
-            .interval(Duration::from_millis(100u64))
-            .stream()
-            .map(|x| 2 * x);
-        assert_eq!(stream.next().await.unwrap(), 2);
-        assert_eq!(stream.next().await.unwrap(), 4);
-        assert_eq!(stream.next().await.unwrap(), 6);
-        // this will poll the factory function again since it consumed the entire
-        // vector, so it'll wrap around. Realistically, we'd then sleep for a few seconds
-        // until new blocks are mined, until the call to the factory returns a non-empty
-        // vector of logs
-        assert_eq!(stream.next().await.unwrap(), 2);
-    }
-}

ethers-providers/tests/provider.rs

@@ -70,7 +70,7 @@ mod eth_tests {
     #[cfg(feature = "tokio-runtime")]
     async fn watch_blocks_websocket() {
         use ethers::{
-            providers::{FilterStream, StreamExt, Ws},
+            providers::{StreamExt, Ws},
             types::H256,
         };
 
@@ -154,10 +154,7 @@ mod eth_tests {
 #[cfg(feature = "celo")]
 mod celo_tests {
     use super::*;
-    use ethers::{
-        providers::FilterStream,
-        types::{Randomness, H256},
-    };
+    use ethers::types::{Randomness, H256};
     use futures_util::stream::StreamExt;
     use rustc_hex::FromHex;
 

ethers-signers/src/lib.rs

@@ -43,7 +43,10 @@ pub use wallet::Wallet;
 #[cfg(feature = "ledger")]
 mod ledger;
 #[cfg(feature = "ledger")]
-pub use ledger::{app::LedgerEthereum as Ledger, types::{LedgerError, DerivationType as HDPath}};
+pub use ledger::{
+    app::LedgerEthereum as Ledger,
+    types::{DerivationType as HDPath, LedgerError},
+};
 
 mod nonce_manager;
 pub(crate) use nonce_manager::NonceManager;

ethers/examples/ledger.rs

@@ -1,8 +1,9 @@
-use anyhow::Result;
-use ethers::{utils::parse_ether, prelude::*};
-
 #[tokio::main]
+#[cfg(feature = "ledger")]
 async fn main() -> Result<()> {
+    use anyhow::Result;
+    use ethers::{prelude::*, utils::parse_ether};
+
     // Connect over websockets
     let provider = Provider::new(Ws::connect("ws://localhost:8545").await?);
     // Instantiate the connection to ledger with Ledger Live derivation path and
@@ -20,6 +21,9 @@ async fn main() -> Result<()> {
     let tx_hash = client.send_transaction(tx, None).await?;
 
     // Get the receipt
-    let receipt = client.pending_transaction(tx_hash).confirmations(3).await?;
+    let _receipt = client.pending_transaction(tx_hash).confirmations(3).await?;
     Ok(())
 }
+
+#[cfg(not(feature = "ledger"))]
+fn main() {}