Method del_change

atomic-core/src/pristine/txn/write/mod.rs:1123–1248

(
        &mut self,
        view: &mut ViewState,
        change_id: NodeId,
        _change_hash: &Hash,
    )

    }

    fn del_change(
        &mut self,
        view: &mut ViewState,
        change_id: NodeId,
        _change_hash: &Hash,
    ) -> PristineResult<Option<u64>> {
        // Find the sequence number for this change
        let seq = {
            let table = self.txn.open_table(REV_VIEW_CHANGES)?;
            let key = encode_view_seq(view.id, change_id.get());
            let result = table.get(&key)?;
            match result {
                Some(value) => {
                    let v = value.value();
                    drop(value);
                    v
                }
                None => return Ok(None), // Change not in this view
            }
        };

        // Remove from VIEW_CHANGES
        {
            let mut table = self.txn.open_table(VIEW_CHANGES)?;
            let key = encode_view_seq(view.id, seq);
            table.remove(&key)?;
        }

        // Remove from REV_VIEW_CHANGES
        {
            let mut table = self.txn.open_table(REV_VIEW_CHANGES)?;
            let key = encode_view_seq(view.id, change_id.get());
            table.remove(&key)?;
        }

        // Remove from MERKLE_CHAIN (the merkle state at this sequence)
        {
            let mut table = self.txn.open_table(MERKLE_CHAIN)?;
            let key = encode_view_seq(view.id, seq);
            table.remove(&key)?;
        }

        // Shift all subsequent changes down by 1
        // We need to update sequences from seq+1 to change_count-1
        let original_count = view.change_count;
        for s in (seq + 1)..original_count {
            // Get the change_id at this sequence
            let cid = {
                let table = self.txn.open_table(VIEW_CHANGES)?;
                let key = encode_view_seq(view.id, s);
                let result = table.get(&key)?;
                match result {
                    Some(v) => {
                        let id = NodeId::new(v.value());
                        drop(v);
                        id
                    }
                    None => continue,