274 lines
9.2 KiB
Rust
274 lines
9.2 KiB
Rust
#![allow(clippy::return_self_not_must_use)]
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use crate::{log::LogMeta, stream::EventStream, ContractError, EthLogDecode};
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use ethers_core::{
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abi::{Detokenize, RawLog},
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types::{BlockNumber, Filter, Log, Topic, H256},
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};
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use ethers_providers::{FilterWatcher, Middleware, PubsubClient, SubscriptionStream};
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use std::{borrow::Cow, marker::PhantomData};
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/// A trait for implementing event bindings
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pub trait EthEvent: Detokenize + Send + Sync {
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/// The name of the event this type represents
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fn name() -> Cow<'static, str>;
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/// Retrieves the signature for the event this data corresponds to.
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/// This signature is the Keccak-256 hash of the ABI signature of
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/// this event.
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fn signature() -> H256;
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/// Retrieves the ABI signature for the event this data corresponds
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/// to.
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fn abi_signature() -> Cow<'static, str>;
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/// Decodes an Ethereum `RawLog` into an instance of the type.
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fn decode_log(log: &RawLog) -> Result<Self, ethers_core::abi::Error>
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where
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Self: Sized;
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/// Returns true if this is an anonymous event
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fn is_anonymous() -> bool;
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/// Returns an Event builder for the ethereum event represented by this types ABI signature.
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fn new<M: Middleware>(filter: Filter, provider: &M) -> Event<M, Self>
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where
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Self: Sized,
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{
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let filter = filter.event(&Self::abi_signature());
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Event { filter, provider, datatype: PhantomData }
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}
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}
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// Convenience implementation
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impl<T: EthEvent> EthLogDecode for T {
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fn decode_log(log: &RawLog) -> Result<Self, ethers_core::abi::Error>
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where
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Self: Sized,
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{
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T::decode_log(log)
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}
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}
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/// Helper for managing the event filter before querying or streaming its logs
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#[derive(Debug)]
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#[must_use = "event filters do nothing unless you `query` or `stream` them"]
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pub struct Event<'a, M, D> {
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/// The event filter's state
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pub filter: Filter,
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pub(crate) provider: &'a M,
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/// Stores the event datatype
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pub(crate) datatype: PhantomData<D>,
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}
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// TODO: Improve these functions
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impl<M, D: EthLogDecode> Event<'_, M, D> {
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/// Sets the filter's `from` block
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#[allow(clippy::wrong_self_convention)]
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pub fn from_block<T: Into<BlockNumber>>(mut self, block: T) -> Self {
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self.filter = self.filter.from_block(block);
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self
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}
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/// Sets the filter's `to` block
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#[allow(clippy::wrong_self_convention)]
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pub fn to_block<T: Into<BlockNumber>>(mut self, block: T) -> Self {
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self.filter = self.filter.to_block(block);
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self
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}
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/// Sets the filter's `blockHash`. Setting this will override previously
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/// set `from_block` and `to_block` fields.
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#[allow(clippy::wrong_self_convention)]
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pub fn at_block_hash<T: Into<H256>>(mut self, hash: T) -> Self {
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self.filter = self.filter.at_block_hash(hash);
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self
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}
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/// Sets the filter's 0th topic (typically the event name for non-anonymous events)
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pub fn topic0<T: Into<Topic>>(mut self, topic: T) -> Self {
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self.filter.topics[0] = Some(topic.into());
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self
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}
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/// Sets the filter's 1st topic
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pub fn topic1<T: Into<Topic>>(mut self, topic: T) -> Self {
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self.filter.topics[1] = Some(topic.into());
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self
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}
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/// Sets the filter's 2nd topic
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pub fn topic2<T: Into<Topic>>(mut self, topic: T) -> Self {
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self.filter.topics[2] = Some(topic.into());
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self
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}
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/// Sets the filter's 3rd topic
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pub fn topic3<T: Into<Topic>>(mut self, topic: T) -> Self {
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self.filter.topics[3] = Some(topic.into());
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self
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}
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}
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impl<'a, M, D> Event<'a, M, D>
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where
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M: Middleware,
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D: EthLogDecode,
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{
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/// Turns this event filter into `Stream` that yields decoded events.
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///
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/// This will first install a new logs filter via [`eth_newFilter`](https://docs.alchemy.com/alchemy/apis/ethereum/eth-newfilter) using the configured `filter` object. See also [`FilterWatcher`](ethers_providers::FilterWatcher).
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///
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/// Once the filter is created, this will periodically call [`eth_getFilterChanges`](https://docs.alchemy.com/alchemy/apis/ethereum/eth-getfilterchanges) to get the newest logs and decode them
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///
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/// **Note:** Compared to [`Self::subscribe`], which is only available on `PubsubClient`s, such
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/// as Websocket, this is a poll-based subscription, as the node does not notify us when a new
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/// matching log is available, instead we have to actively ask for new logs using additional RPC
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/// requests, and this is done on an interval basis.
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///
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/// # Example
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///
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/// ```
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/// # #[cfg(feature = "abigen")]
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/// # async fn test<M:ethers_providers::Middleware>(contract: ethers_contract::Contract<M>) {
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/// # use ethers_core::types::*;
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/// # use futures_util::stream::StreamExt;
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/// # use ethers_contract::{Contract, EthEvent};
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///
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/// // The event we want to get
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/// #[derive(Clone, Debug, EthEvent)]
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/// pub struct Approval {
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/// #[ethevent(indexed)]
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/// pub token_owner: Address,
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/// #[ethevent(indexed)]
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/// pub spender: Address,
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/// pub tokens: U256,
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/// }
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///
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/// let ev = contract.event::<Approval>().from_block(1337).to_block(2000);
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/// let mut event_stream = ev.stream().await.unwrap();
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///
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/// while let Some(Ok(approval)) = event_stream.next().await {
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/// let Approval{token_owner,spender,tokens} = approval;
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/// }
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///
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/// # }
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/// ```
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pub async fn stream(
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&'a self,
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) -> Result<
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// Wraps the FilterWatcher with a mapping to the event
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EventStream<'a, FilterWatcher<'a, M::Provider, Log>, D, ContractError<M>>,
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ContractError<M>,
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> {
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let filter =
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self.provider.watch(&self.filter).await.map_err(ContractError::MiddlewareError)?;
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Ok(EventStream::new(filter.id, filter, Box::new(move |log| self.parse_log(log))))
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}
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/// As [`Self::stream`], but does not discard [`Log`] metadata.
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pub async fn stream_with_meta(
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&'a self,
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) -> Result<
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// Wraps the FilterWatcher with a mapping to the event
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EventStream<'a, FilterWatcher<'a, M::Provider, Log>, (D, LogMeta), ContractError<M>>,
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ContractError<M>,
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> {
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let filter =
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self.provider.watch(&self.filter).await.map_err(ContractError::MiddlewareError)?;
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Ok(EventStream::new(
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filter.id,
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filter,
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Box::new(move |log| {
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let meta = LogMeta::from(&log);
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Ok((self.parse_log(log)?, meta))
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}),
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))
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}
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}
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impl<'a, M, D> Event<'a, M, D>
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where
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M: Middleware,
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<M as Middleware>::Provider: PubsubClient,
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D: EthLogDecode,
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{
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/// Returns a subscription for the event
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///
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/// See also [Self::stream()].
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pub async fn subscribe(
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&'a self,
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) -> Result<
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// Wraps the SubscriptionStream with a mapping to the event
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EventStream<'a, SubscriptionStream<'a, M::Provider, Log>, D, ContractError<M>>,
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ContractError<M>,
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> {
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let filter = self
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.provider
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.subscribe_logs(&self.filter)
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.await
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.map_err(ContractError::MiddlewareError)?;
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Ok(EventStream::new(filter.id, filter, Box::new(move |log| self.parse_log(log))))
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}
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pub async fn subscribe_with_meta(
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&'a self,
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) -> Result<
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// Wraps the SubscriptionStream with a mapping to the event
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EventStream<'a, SubscriptionStream<'a, M::Provider, Log>, (D, LogMeta), ContractError<M>>,
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ContractError<M>,
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> {
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let filter = self
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.provider
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.subscribe_logs(&self.filter)
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.await
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.map_err(ContractError::MiddlewareError)?;
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Ok(EventStream::new(
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filter.id,
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filter,
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Box::new(move |log| {
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let meta = LogMeta::from(&log);
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Ok((self.parse_log(log)?, meta))
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}),
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))
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}
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}
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impl<M, D> Event<'_, M, D>
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where
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M: Middleware,
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D: EthLogDecode,
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{
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/// Queries the blockchain for the selected filter and returns a vector of matching
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/// event logs
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pub async fn query(&self) -> Result<Vec<D>, ContractError<M>> {
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let logs =
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self.provider.get_logs(&self.filter).await.map_err(ContractError::MiddlewareError)?;
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let events = logs
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.into_iter()
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.map(|log| self.parse_log(log))
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.collect::<Result<Vec<_>, ContractError<M>>>()?;
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Ok(events)
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}
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/// Queries the blockchain for the selected filter and returns a vector of logs
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/// along with their metadata
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pub async fn query_with_meta(&self) -> Result<Vec<(D, LogMeta)>, ContractError<M>> {
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let logs =
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self.provider.get_logs(&self.filter).await.map_err(ContractError::MiddlewareError)?;
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let events = logs
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.into_iter()
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.map(|log| {
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let meta = LogMeta::from(&log);
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let event = self.parse_log(log)?;
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Ok((event, meta))
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})
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.collect::<Result<_, ContractError<M>>>()?;
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Ok(events)
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}
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pub fn parse_log(&self, log: Log) -> Result<D, ContractError<M>> {
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D::decode_log(&RawLog { topics: log.topics, data: log.data.to_vec() }).map_err(From::from)
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}
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}
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