use std::fmt;
use common::BitSet;
use crate::core::{SegmentId, SegmentMeta};
use crate::indexer::delete_queue::DeleteCursor;
/// A segment entry describes the state of
/// a given segment, at a given instant.
///
/// In addition to segment `meta`,
/// it contains a few transient states
/// - `alive_bitset` is a bitset describing
/// documents that were alive during the commit
/// itself.
/// - `delete_cursor` is the position in the delete queue.
/// Deletes happening before the cursor are reflected either
/// in the .del file or in the `alive_bitset`.
#[derive(Clone)]
pub struct SegmentEntry {
meta: SegmentMeta,
alive_bitset: Option<BitSet>,
delete_cursor: DeleteCursor,
}
impl SegmentEntry {
/// Create a new `SegmentEntry`
pub fn new(
segment_meta: SegmentMeta,
delete_cursor: DeleteCursor,
alive_bitset: Option<BitSet>,
) -> SegmentEntry {
SegmentEntry {
meta: segment_meta,
alive_bitset,
delete_cursor,
}
}
/// Return a reference to the segment entry deleted bitset.
///
/// `DocId` in this bitset are flagged as deleted.
pub fn alive_bitset(&self) -> Option<&BitSet> {
self.alive_bitset.as_ref()
}
/// Set the `SegmentMeta` for this segment.
pub fn set_meta(&mut self, segment_meta: SegmentMeta) {
self.meta = segment_meta;
}
/// Return a reference to the segment_entry's delete cursor
pub fn delete_cursor(&mut self) -> &mut DeleteCursor {
&mut self.delete_cursor
}
/// Returns the segment id.
pub fn segment_id(&self) -> SegmentId {
self.meta.id()
}
/// Accessor to the `SegmentMeta`
pub fn meta(&self) -> &SegmentMeta {
&self.meta
}
}
impl fmt::Debug for SegmentEntry {
fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(formatter, "SegmentEntry({:?})", self.meta)
}
}