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https://github.com/0glabs/0g-storage-node.git
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294 lines
10 KiB
Rust
294 lines
10 KiB
Rust
// Copyright 2019 Parity Technologies (UK) Ltd.
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//
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// Permission is hereby granted, free of charge, to any person obtaining a
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// copy of this software and associated documentation files (the "Software"),
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// to deal in the Software without restriction, including without limitation
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// the rights to use, copy, modify, merge, publish, distribute, sublicense,
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// and/or sell copies of the Software, and to permit persons to whom the
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// Software is furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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// DEALINGS IN THE SOFTWARE.
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// This basis of this file has been taken from the rust-libp2p codebase:
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// https://github.com/libp2p/rust-libp2p
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mod peers;
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pub use peers::QueryState;
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pub(crate) use peers::{
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closest::{FindNodeQuery, FindNodeQueryConfig},
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predicate::{PredicateQuery, PredicateQueryConfig},
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};
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use crate::kbucket::{Key, PredicateKey};
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use fnv::FnvHashMap;
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use std::time::{Duration, Instant};
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pub trait TargetKey<TNodeId> {
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fn key(&self) -> Key<TNodeId>;
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}
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/// A `QueryPool` provides an aggregate state machine for driving `Query`s to completion.
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///
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/// Internally, a `Query` is in turn driven by an underlying `QueryPeerIter`
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/// that determines the peer selection strategy, i.e. the order in which the
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/// peers involved in the query should be contacted.
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pub struct QueryPool<TTarget, TNodeId, TResult> {
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next_id: usize,
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query_timeout: Duration,
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queries: FnvHashMap<QueryId, Query<TTarget, TNodeId, TResult>>,
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}
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/// The observable states emitted by [`QueryPool::poll`].
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#[allow(clippy::type_complexity)]
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pub enum QueryPoolState<'a, TTarget, TNodeId, TResult> {
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/// The pool is idle, i.e. there are no queries to process.
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Idle,
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/// At least one query is waiting for results. `Some(request)` indicates
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/// that a new request is now being waited on.
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Waiting(Option<(&'a mut Query<TTarget, TNodeId, TResult>, TNodeId)>),
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/// A query has finished.
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Finished(Query<TTarget, TNodeId, TResult>),
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/// A query has timed out.
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Timeout(Query<TTarget, TNodeId, TResult>),
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}
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impl<TTarget, TNodeId, TResult> QueryPool<TTarget, TNodeId, TResult>
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where
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TTarget: TargetKey<TNodeId>,
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TNodeId: Into<Key<TNodeId>> + Eq + Clone,
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TResult: Into<TNodeId> + Clone,
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{
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/// Creates a new `QueryPool` with the given configuration.
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pub fn new(query_timeout: Duration) -> Self {
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QueryPool {
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next_id: 0,
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query_timeout,
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queries: Default::default(),
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}
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}
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/// Returns an iterator over the queries in the pool.
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pub fn iter(&self) -> impl Iterator<Item = &Query<TTarget, TNodeId, TResult>> {
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self.queries.values()
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}
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/// Adds a query to the pool that iterates towards the closest peers to the target.
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pub fn add_findnode_query<I>(
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&mut self,
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config: FindNodeQueryConfig,
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target: TTarget,
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peers: I,
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) -> QueryId
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where
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I: IntoIterator<Item = Key<TNodeId>>,
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{
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let target_key = target.key();
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let findnode_query = FindNodeQuery::with_config(config, target_key, peers);
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let peer_iter = QueryPeerIter::FindNode(findnode_query);
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self.add(peer_iter, target)
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}
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/// Adds a query to the pool that returns peers that satisfy a predicate.
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pub(crate) fn add_predicate_query<I>(
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&mut self,
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config: PredicateQueryConfig,
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target: TTarget,
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peers: I,
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predicate: impl Fn(&TResult) -> bool + Send + 'static,
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) -> QueryId
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where
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I: IntoIterator<Item = PredicateKey<TNodeId>>,
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{
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let target_key = target.key();
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let predicate_query = PredicateQuery::with_config(config, target_key, peers, predicate);
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let peer_iter = QueryPeerIter::Predicate(predicate_query);
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self.add(peer_iter, target)
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}
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fn add(&mut self, peer_iter: QueryPeerIter<TNodeId, TResult>, target: TTarget) -> QueryId {
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let id = QueryId(self.next_id);
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self.next_id = self.next_id.wrapping_add(1);
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let query = Query::new(id, peer_iter, target);
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self.queries.insert(id, query);
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id
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}
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/// Returns a mutable reference to a query with the given ID, if it is in the pool.
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pub fn get_mut(&mut self, id: QueryId) -> Option<&mut Query<TTarget, TNodeId, TResult>> {
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self.queries.get_mut(&id)
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}
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/// Polls the pool to advance the queries.
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pub fn poll(&mut self) -> QueryPoolState<'_, TTarget, TNodeId, TResult> {
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let now = Instant::now();
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let mut finished = None;
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let mut waiting = None;
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let mut timeout = None;
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for (&query_id, query) in self.queries.iter_mut() {
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query.started = query.started.or(Some(now));
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match query.next(now) {
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QueryState::Finished => {
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finished = Some(query_id);
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break;
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}
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QueryState::Waiting(Some(return_peer)) => {
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waiting = Some((query_id, return_peer));
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break;
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}
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QueryState::Waiting(None) | QueryState::WaitingAtCapacity => {
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let elapsed = now - query.started.unwrap_or(now);
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if elapsed >= self.query_timeout {
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timeout = Some(query_id);
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break;
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}
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}
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}
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}
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if let Some((query_id, return_peer)) = waiting {
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let query = self.queries.get_mut(&query_id).expect("s.a.");
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return QueryPoolState::Waiting(Some((query, return_peer)));
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}
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if let Some(query_id) = finished {
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let query = self.queries.remove(&query_id).expect("s.a.");
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return QueryPoolState::Finished(query);
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}
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if let Some(query_id) = timeout {
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let query = self.queries.remove(&query_id).expect("s.a.");
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return QueryPoolState::Timeout(query);
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}
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if self.queries.is_empty() {
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QueryPoolState::Idle
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} else {
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QueryPoolState::Waiting(None)
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}
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}
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}
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/// Unique identifier for an active query.
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#[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
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pub struct QueryId(pub usize);
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impl std::ops::Deref for QueryId {
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type Target = usize;
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fn deref(&self) -> &Self::Target {
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&self.0
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}
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}
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/// A query in a `QueryPool`.
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pub struct Query<TTarget, TNodeId, TResult> {
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/// The unique ID of the query.
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id: QueryId,
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/// The peer iterator that drives the query state.
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peer_iter: QueryPeerIter<TNodeId, TResult>,
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/// The instant when the query started (i.e. began waiting for the first
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/// result from a peer).
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started: Option<Instant>,
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/// Target we are looking for.
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target: TTarget,
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}
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/// The peer selection strategies that can be used by queries.
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enum QueryPeerIter<TNodeId, TResult> {
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FindNode(FindNodeQuery<TNodeId>),
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Predicate(PredicateQuery<TNodeId, TResult>),
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}
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impl<TTarget, TNodeId, TResult> Query<TTarget, TNodeId, TResult>
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where
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TTarget: TargetKey<TNodeId>,
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TNodeId: Into<Key<TNodeId>> + Eq + Clone,
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TResult: Into<TNodeId> + Clone,
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{
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/// Creates a new query without starting it.
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fn new(id: QueryId, peer_iter: QueryPeerIter<TNodeId, TResult>, target: TTarget) -> Self {
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Query {
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id,
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peer_iter,
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target,
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started: None,
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}
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}
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/// Gets the unique ID of the query.
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pub fn id(&self) -> QueryId {
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self.id
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}
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/// Informs the query that the attempt to contact `peer` failed.
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pub fn on_failure(&mut self, peer: &TNodeId) {
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match &mut self.peer_iter {
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QueryPeerIter::FindNode(iter) => iter.on_failure(peer),
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QueryPeerIter::Predicate(iter) => iter.on_failure(peer),
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}
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}
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/// Informs the query that the attempt to contact `peer` succeeded,
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/// possibly resulting in new peers that should be incorporated into
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/// the query, if applicable.
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pub fn on_success<'a>(&mut self, peer: &TNodeId, new_peers: &'a [TResult])
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where
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&'a TResult: Into<TNodeId>,
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{
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match &mut self.peer_iter {
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QueryPeerIter::FindNode(iter) => {
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iter.on_success(peer, new_peers.iter().map(|result| result.into()).collect())
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}
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QueryPeerIter::Predicate(iter) => iter.on_success(peer, new_peers),
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}
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}
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/// Advances the state of the underlying peer iterator.
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fn next(&mut self, now: Instant) -> QueryState<TNodeId> {
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match &mut self.peer_iter {
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QueryPeerIter::FindNode(iter) => iter.next(now),
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QueryPeerIter::Predicate(iter) => iter.next(now),
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}
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}
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/// Consumes the query, producing the final `QueryResult`.
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pub fn into_result(self) -> QueryResult<TTarget, impl Iterator<Item = TNodeId>> {
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let peers = match self.peer_iter {
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QueryPeerIter::FindNode(iter) => iter.into_result(),
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QueryPeerIter::Predicate(iter) => iter.into_result(),
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};
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QueryResult {
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target: self.target,
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closest_peers: peers.into_iter(),
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}
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}
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/// Returns a reference to the query `target`.
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pub fn target(&self) -> &TTarget {
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&self.target
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}
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/// Returns a mutable reference to the query `target`.
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pub fn target_mut(&mut self) -> &mut TTarget {
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&mut self.target
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}
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}
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/// The result of a `Query`.
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pub struct QueryResult<TTarget, TClosest> {
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/// The target of the query.
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pub target: TTarget,
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/// The closest peers to the target found by the query.
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pub closest_peers: TClosest,
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}
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