Function build_blob_file_bytes

crates/blob_test_utils.rs:25–67

(rows: &[Option<&[u8]>])

const BLOB_FORMAT_VERSION: u8 = 1;

pub(crate) fn build_blob_file_bytes(rows: &[Option<&[u8]>]) -> Vec<u8> {
    let mut file_bytes = Vec::new();
    let mut lengths = Vec::with_capacity(rows.len());

    for row in rows {
        match row {
            Some(payload) => {
                let entry_length = payload
                    .len()
                    .checked_add(BLOB_ENTRY_OVERHEAD)
                    .and_then(|len| i64::try_from(len).ok())
                    .unwrap_or_else(|| {
                        panic!("Blob payload length {} exceeds test helper limits", payload.len())
                    });
                lengths.push(entry_length);

                file_bytes.extend_from_slice(&BLOB_MAGIC_NUMBER_BYTES);
                file_bytes.extend_from_slice(payload);
                let mut hasher = crc32fast::Hasher::new();
                hasher.update(&BLOB_MAGIC_NUMBER_BYTES);
                hasher.update(payload);

                let entry_length_bytes = entry_length.to_le_bytes();
                file_bytes.extend_from_slice(&entry_length_bytes);
                hasher.update(&entry_length_bytes);
                file_bytes.extend_from_slice(&hasher.finalize().to_le_bytes());
            }
            None => lengths.push(-1),
        }
    }

    let index_bytes = encode_delta_varints(&lengths);
    let index_length = i32::try_from(index_bytes.len()).unwrap_or_else(|_| {
        panic!(
            "Blob index length {} exceeds test helper limits",
            index_bytes.len()
        )
    });
    file_bytes.extend_from_slice(&index_bytes);
    file_bytes.extend_from_slice(&index_length.to_le_bytes());
    file_bytes.push(BLOB_FORMAT_VERSION);
    file_bytes
}

pub(crate) fn write_blob_file(path: &Path, rows: &[Option<&[u8]>]) {
    let file_bytes = build_blob_file_bytes(rows);