Rewrite one segment according to `action`. Returns the number of tile-versions dropped (i.e. `action.drop_tile_ids.len()`).
(store: &mut ArrayStore, action: &SegmentPurgeAction)
| 66 | /// Rewrite one segment according to `action`. Returns the number of |
| 67 | /// tile-versions dropped (i.e. `action.drop_tile_ids.len()`). |
| 68 | fn rewrite_segment(store: &mut ArrayStore, action: &SegmentPurgeAction) -> Result<u64, ArrayError> { |
| 69 | let dropped_count = action.drop_tile_ids.len() as u64; |
| 70 | |
| 71 | // ── Read phase: all borrows from `store` end before this function ────────── |
| 72 | // modifies `store`. Collect owned data. |
| 73 | let result = { |
| 74 | let seg_ref = store |
| 75 | .manifest() |
| 76 | .segments |
| 77 | .iter() |
| 78 | .find(|s| s.id == action.segment_id) |
| 79 | .ok_or_else(|| ArrayError::SegmentCorruption { |
| 80 | detail: format!("purge: segment {} not in manifest", action.segment_id), |
| 81 | })? |
| 82 | .clone(); |
| 83 | |
| 84 | let schema_hash = store.schema_hash(); |
| 85 | let kek = store.kek().cloned(); |
| 86 | |
| 87 | let handle = store.segments.get(&action.segment_id).ok_or_else(|| { |
| 88 | ArrayError::SegmentCorruption { |
| 89 | detail: format!("purge: no open handle for segment {}", action.segment_id), |
| 90 | } |
| 91 | })?; |
| 92 | |
| 93 | let reader = handle.reader(); |
| 94 | let source_tiles: Vec<_> = reader.tiles().to_vec(); |
| 95 | |
| 96 | let surviving: Vec<TileId> = source_tiles |
| 97 | .iter() |
| 98 | .filter(|e| !action.drop_tile_ids.contains(&e.tile_id)) |
| 99 | .map(|e| e.tile_id) |
| 100 | .collect(); |
| 101 | |
| 102 | let has_ceiling = !action.emit_ceiling_tiles.is_empty(); |
| 103 | let is_empty_after_rewrite = surviving.is_empty() && !has_ceiling; |
| 104 | |
| 105 | if is_empty_after_rewrite && dropped_count == 0 { |
| 106 | ReadPhaseResult::Noop |
| 107 | } else if is_empty_after_rewrite { |
| 108 | ReadPhaseResult::RemoveEntirely { seg_ref } |
| 109 | } else { |
| 110 | // Build new segment bytes from surviving tiles + ceiling tiles. |
| 111 | let mut all_output_ids: Vec<TileId> = surviving.clone(); |
| 112 | for (ceiling_id, _) in &action.emit_ceiling_tiles { |
| 113 | all_output_ids.push(*ceiling_id); |
| 114 | } |
| 115 | all_output_ids.sort(); |
| 116 | |
| 117 | let mut writer = SegmentWriter::new(schema_hash); |
| 118 | let mut new_min_tile: Option<TileId> = None; |
| 119 | let mut new_max_tile: Option<TileId> = None; |
| 120 | let mut new_tile_count: u32 = 0; |
| 121 | |
| 122 | for output_id in &all_output_ids { |
| 123 | if let Some((_cid, ceiling_tile)) = action |
| 124 | .emit_ceiling_tiles |
| 125 | .iter() |
no test coverage detected