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use crate::core::SegmentId;
use crate::core::SegmentMeta;
use std::fmt::Debug;
use std::marker;
#[derive(Debug, Clone)]
pub struct MergeCandidate(pub Vec<SegmentId>);
pub trait MergePolicy: marker::Send + marker::Sync + Debug {
fn compute_merge_candidates(&self, segments: &[SegmentMeta]) -> Vec<MergeCandidate>;
}
#[derive(Debug, Clone)]
pub struct NoMergePolicy;
impl Default for NoMergePolicy {
fn default() -> NoMergePolicy {
NoMergePolicy
}
}
impl MergePolicy for NoMergePolicy {
fn compute_merge_candidates(&self, _segments: &[SegmentMeta]) -> Vec<MergeCandidate> {
Vec::new()
}
}
#[cfg(test)]
pub mod tests {
use super::*;
use crate::core::SegmentId;
use crate::core::SegmentMeta;
#[derive(Debug, Clone)]
pub struct MergeWheneverPossible;
impl MergePolicy for MergeWheneverPossible {
fn compute_merge_candidates(&self, segment_metas: &[SegmentMeta]) -> Vec<MergeCandidate> {
let segment_ids = segment_metas
.iter()
.map(|segment_meta| segment_meta.id())
.collect::<Vec<SegmentId>>();
if segment_ids.len() > 1 {
vec![MergeCandidate(segment_ids)]
} else {
vec![]
}
}
}
}