mirror of https://github.com/poanetwork/hbbft.git
35 lines
1.3 KiB
Rust
35 lines
1.3 KiB
Rust
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use std::cmp;
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use std::collections::{HashSet, VecDeque};
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use std::hash::Hash;
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use rand;
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/// A wrapper providing a few convenience methods for a queue of pending transactions.
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#[derive(Debug)]
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pub struct TransactionQueue<Tx>(pub VecDeque<Tx>);
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impl<Tx: Clone> TransactionQueue<Tx> {
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/// Removes the given transactions from the queue.
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pub fn remove_all<'a, I>(&mut self, txs: I)
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where
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I: IntoIterator<Item = &'a Tx>,
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Tx: Eq + Hash + 'a,
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{
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let tx_set: HashSet<_> = txs.into_iter().collect();
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self.0.retain(|tx| !tx_set.contains(tx));
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}
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/// Returns a new set of `amount` transactions, randomly chosen from the first `batch_size`.
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/// No transactions are removed from the queue.
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// TODO: Return references, once the `HoneyBadger` API accepts them. Remove `Clone` bound.
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pub fn choose(&self, amount: usize, batch_size: usize) -> Vec<Tx> {
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let mut rng = rand::thread_rng();
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let limit = cmp::min(batch_size, self.0.len());
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let sample = match rand::seq::sample_iter(&mut rng, self.0.iter().take(limit), amount) {
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Ok(choice) => choice,
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Err(choice) => choice, // Fewer than `amount` were available, which is fine.
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};
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sample.into_iter().cloned().collect()
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}
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}
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