block_db/
free.rs

1// Authors: Robert Lopez
2
3use super::{error::Error, BlockDB, BlockKey};
4
5impl BlockDB {
6    /// Frees the `DataBlock` (`data_block_id`) within `DataFile` (`data_file_id`)
7    /// by marking its chunks as "free".
8    ///
9    /// **Once marked as free, the `DataBlock` is unrecoverable**, making this
10    /// operation functionally equivalent to a delete.
11    ///
12    /// Freed space will be reused in future writes. To physically remove the
13    /// freed bytes from the underlying `DataFile`, use `BlockDB::compact_data_file(s)`.
14    ///
15    /// Returns the total number of bytes freed.
16    ///
17    /// ---
18    /// - **Atomic**
19    /// - **Non-corruptible**
20    ///
21    /// ---
22    /// Example
23    /// ```
24    /// let block_db = BlockDB::open("./data", None).await?;
25    ///
26    /// let block_key = block_db.write(b"Hello World").await?;
27    ///
28    /// let freed_bytes: usize = block_db.free(&block_key).await?;
29    /// ```
30    pub async fn free(
31        &mut self,
32        BlockKey {
33            data_file_id,
34            data_block_id,
35        }: &BlockKey,
36    ) -> Result<usize, Error> {
37        if let Some(data_file) = self.data_files.read().await.get(data_file_id).cloned() {
38            return data_file.write().await.free(data_block_id).await;
39        }
40
41        Ok(0)
42    }
43}
block_db/free.rs

block_db/
free.rs
