crabka-client-streams 0.3.6

KIP-1071 Kafka Streams rebalance-protocol client for Apache Kafka in Rust
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51

//! A single record-cache entry: value bytes (None = tombstone), dirty flag, and
//! the record context needed to forward the entry downstream on flush.
use crate::processor::record::RecordContext;
use bytes::Bytes;

#[derive(Clone, Debug)]
pub(crate) struct LruCacheEntry {
    pub value: Option<Bytes>,
    pub dirty: bool,
    pub context: RecordContext,
}

impl LruCacheEntry {
    pub fn new(value: Option<Bytes>, dirty: bool, context: RecordContext) -> Self {
        Self {
            value,
            dirty,
            context,
        }
    }

    /// Heap footprint for `ThreadCache` budget accounting. Ports Kafka's
    /// `LRUCacheEntry.size()`: value bytes + context overhead
    /// (8 timestamp + 8 offset + 4 partition + topic bytes). Key length is added
    /// by `NamedCache` (it owns the key).
    pub fn value_size(&self) -> usize {
        let v = self.value.as_ref().map_or(0, Bytes::len);
        v + 8 + 8 + 4 + self.context.topic.len()
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    fn ctx(topic: &str) -> RecordContext {
        RecordContext {
            topic: topic.to_string(),
            partition: 0,
            offset: 0,
            timestamp: 0,
        }
    }

    #[test]
    fn value_size_counts_value_and_context() {
        let entry = LruCacheEntry::new(Some(Bytes::from_static(b"abcd")), false, ctx("t"));
        // 4 (value) + 8 + 8 + 4 + 1 (topic "t") = 25
        assert_eq!(entry.value_size(), 25);
    }
}