70 lines
1.8 KiB
Rust
70 lines
1.8 KiB
Rust
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use std::collections::HashMap;
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#[derive(Debug, Clone)]
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pub struct VersionedValue {
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pub value: Vec<u8>,
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pub version: u64,
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}
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#[derive(Debug, Clone, Default)]
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pub struct GossipState {
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entries: HashMap<String, VersionedValue>,
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}
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impl GossipState {
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pub fn new() -> Self {
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Self::default()
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}
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/// Insert or update a key. Auto-increments the version for that key.
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/// Returns the new version number.
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pub fn set(&mut self, key: String, value: Vec<u8>) -> u64 {
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let new_version = self
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.entries
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.get(&key)
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.map_or(1, |existing| existing.version + 1);
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self.entries.insert(
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key,
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VersionedValue {
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value,
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version: new_version,
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},
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);
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new_version
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}
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pub fn get(&self, key: &str) -> Option<&VersionedValue> {
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self.entries.get(key)
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}
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pub fn entries(&self) -> &HashMap<String, VersionedValue> {
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&self.entries
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}
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pub fn len(&self) -> usize {
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self.entries.len()
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}
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pub fn is_empty(&self) -> bool {
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self.entries.is_empty()
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}
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/// Merge a remote state into this one. For each key, keep the entry
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/// with the higher version (last-writer-wins). Returns the number of
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/// entries that were updated.
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pub fn merge(&mut self, remote: &GossipState) -> usize {
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let mut updated = 0;
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for (key, remote_val) in &remote.entries {
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let dominated = match self.entries.get(key) {
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Some(local_val) => remote_val.version > local_val.version,
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None => true,
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};
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if dominated {
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self.entries.insert(key.clone(), remote_val.clone());
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updated += 1;
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}
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}
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updated
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}
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}
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