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#![allow(clippy::return_self_not_must_use)]
use crate::{
event_core::parse_log, log::LogMeta, stream::EventStream, ContractError, EthLogDecode,
};
use ethers_core::{
abi::Address,
types::{BlockNumber, Filter, Log, Topic, ValueOrArray, H256},
};
use ethers_providers::{FilterWatcher, Middleware, PubsubClient, SubscriptionStream};
use std::{borrow::Borrow, marker::PhantomData};
/// Helper for managing the event filter before querying or streaming its logs
#[derive(Debug)]
#[must_use = "event filters do nothing unless you `query` or `stream` them"]
pub struct Event<B, M, D> {
/// The event filter's state
pub filter: Filter,
pub(crate) provider: B,
/// Stores the event datatype
pub(crate) datatype: PhantomData<D>,
pub(crate) _m: PhantomData<M>,
}
// TODO: Improve these functions
impl<B, M, D> Event<B, M, D>
where
B: Borrow<M>,
M: Middleware,
D: EthLogDecode,
{
/// Sets the filter's `from` block
#[allow(clippy::wrong_self_convention)]
pub fn from_block<T: Into<BlockNumber>>(mut self, block: T) -> Self {
self.filter = self.filter.from_block(block);
self
}
/// Sets the filter's `to` block
#[allow(clippy::wrong_self_convention)]
pub fn to_block<T: Into<BlockNumber>>(mut self, block: T) -> Self {
self.filter = self.filter.to_block(block);
self
}
/// Sets the filter's `blockHash`. Setting this will override previously
/// set `from_block` and `to_block` fields.
#[allow(clippy::wrong_self_convention)]
pub fn at_block_hash<T: Into<H256>>(mut self, hash: T) -> Self {
self.filter = self.filter.at_block_hash(hash);
self
}
/// Sets the filter's 0th topic (typically the event name for non-anonymous events)
pub fn topic0<T: Into<Topic>>(mut self, topic: T) -> Self {
self.filter.topics[0] = Some(topic.into());
self
}
/// Sets the filter's 1st topic
pub fn topic1<T: Into<Topic>>(mut self, topic: T) -> Self {
self.filter.topics[1] = Some(topic.into());
self
}
/// Sets the filter's 2nd topic
pub fn topic2<T: Into<Topic>>(mut self, topic: T) -> Self {
self.filter.topics[2] = Some(topic.into());
self
}
/// Sets the filter's 3rd topic
pub fn topic3<T: Into<Topic>>(mut self, topic: T) -> Self {
self.filter.topics[3] = Some(topic.into());
self
}
/// Sets the filter's address.
pub fn address(mut self, address: ValueOrArray<Address>) -> Self {
self.filter = self.filter.address(address);
self
}
}
impl<B, M, D> Event<B, M, D>
where
B: Borrow<M>,
M: Middleware,
D: EthLogDecode,
{
/// Turns this event filter into `Stream` that yields decoded events.
///
/// This will first install a new logs filter via [`eth_newFilter`] using the configured
/// `filter` object. See also [`FilterWatcher`].
///
///
/// Once the filter is created, this will periodically call [`eth_getFilterChanges`] to get the
/// newest logs and decode them.
///
///
/// **Note:** Compared to [`Self::subscribe`], which is only available on `PubsubClient`s, such
/// as Websocket, this is a poll-based subscription, as the node does not notify us when a new
/// matching log is available, instead we have to actively ask for new logs using additional RPC
/// requests, and this is done on an interval basis.
///
/// [`eth_newFilter`]: https://docs.alchemy.com/alchemy/apis/ethereum/eth-newfilter
/// [`eth_getFilterChanges`]: https://docs.alchemy.com/alchemy/apis/ethereum/eth-getfilterchanges
///
/// # Example
// Ignore because `ethers-contract-derive` macros do not work in doctests in `ethers-contract`.
/// ```ignore
/// # #[cfg(feature = "abigen")]
/// # async fn test<M:ethers_providers::Middleware>(contract: ethers_contract::Contract<M>) {
/// # use ethers_core::types::*;
/// # use futures_util::stream::StreamExt;
/// # use ethers_contract::{Contract, EthEvent};
///
/// // The event we want to get
/// #[derive(Clone, Debug, EthEvent)]
/// pub struct Approval {
/// #[ethevent(indexed)]
/// pub token_owner: Address,
/// #[ethevent(indexed)]
/// pub spender: Address,
/// pub tokens: U256,
/// }
///
/// let ev = contract.event::<Approval>().from_block(1337).to_block(2000);
/// let mut event_stream = ev.stream().await.unwrap();
///
/// while let Some(Ok(approval)) = event_stream.next().await {
/// let Approval{token_owner,spender,tokens} = approval;
/// }
/// # }
/// ```
pub async fn stream(
&self,
) -> Result<
// Wraps the FilterWatcher with a mapping to the event
EventStream<'_, FilterWatcher<'_, M::Provider, Log>, D, ContractError<M>>,
ContractError<M>,
> {
let filter = self
.provider
.borrow()
.watch(&self.filter)
.await
.map_err(ContractError::from_middleware_error)?;
Ok(EventStream::new(filter.id, filter, Box::new(move |log| Ok(parse_log(log)?))))
}
/// As [`Self::stream`], but does not discard [`Log`] metadata.
pub async fn stream_with_meta(
&self,
) -> Result<
// Wraps the FilterWatcher with a mapping to the event
EventStream<'_, FilterWatcher<'_, M::Provider, Log>, (D, LogMeta), ContractError<M>>,
ContractError<M>,
> {
let filter = self
.provider
.borrow()
.watch(&self.filter)
.await
.map_err(ContractError::from_middleware_error)?;
Ok(EventStream::new(
filter.id,
filter,
Box::new(move |log| {
let meta = LogMeta::from(&log);
Ok((parse_log(log)?, meta))
}),
))
}
}
impl<B, M, D> Event<B, M, D>
where
B: Borrow<M>,
M: Middleware,
<M as Middleware>::Provider: PubsubClient,
D: EthLogDecode,
{
/// Returns a subscription for the event
///
/// See also [Self::stream()].
pub async fn subscribe(
&self,
) -> Result<
// Wraps the SubscriptionStream with a mapping to the event
EventStream<'_, SubscriptionStream<'_, M::Provider, Log>, D, ContractError<M>>,
ContractError<M>,
> {
let filter = self
.provider
.borrow()
.subscribe_logs(&self.filter)
.await
.map_err(ContractError::from_middleware_error)?;
Ok(EventStream::new(filter.id, filter, Box::new(move |log| Ok(parse_log(log)?))))
}
/// As [`Self::subscribe`], but includes event metadata
pub async fn subscribe_with_meta(
&self,
) -> Result<
// Wraps the SubscriptionStream with a mapping to the event
EventStream<'_, SubscriptionStream<'_, M::Provider, Log>, (D, LogMeta), ContractError<M>>,
ContractError<M>,
> {
let filter = self
.provider
.borrow()
.subscribe_logs(&self.filter)
.await
.map_err(ContractError::from_middleware_error)?;
Ok(EventStream::new(
filter.id,
filter,
Box::new(move |log| {
let meta = LogMeta::from(&log);
Ok((parse_log(log)?, meta))
}),
))
}
}
impl<B, M, D> Event<B, M, D>
where
B: Borrow<M>,
M: Middleware,
D: EthLogDecode,
{
/// Queries the blockchain for the selected filter and returns a vector of matching
/// event logs
pub async fn query(&self) -> Result<Vec<D>, ContractError<M>> {
let logs = self
.provider
.borrow()
.get_logs(&self.filter)
.await
.map_err(ContractError::from_middleware_error)?;
let events = logs
.into_iter()
.map(|log| Ok(parse_log(log)?))
.collect::<Result<Vec<_>, ContractError<M>>>()?;
Ok(events)
}
/// Queries the blockchain for the selected filter and returns a vector of logs
/// along with their metadata
pub async fn query_with_meta(&self) -> Result<Vec<(D, LogMeta)>, ContractError<M>> {
let logs = self
.provider
.borrow()
.get_logs(&self.filter)
.await
.map_err(ContractError::from_middleware_error)?;
let events = logs
.into_iter()
.map(|log| {
let meta = LogMeta::from(&log);
let event = parse_log(log)?;
Ok((event, meta))
})
.collect::<Result<_, ContractError<M>>>()?;
Ok(events)
}
}