rust-rocksdb/tests/test_slice_transform.rs

mod util;

use crate::util::DBPath;
use rocksdb::{Options, SliceTransform, DB};

#[test]
pub fn test_slice_transform() {
    let db_path = DBPath::new("_rust_rocksdb_slicetransform_test");
    {
        let a1: Box<[u8]> = key(b"aaa1");
        let a2: Box<[u8]> = key(b"aaa2");
        let b1: Box<[u8]> = key(b"bbb1");
        let b2: Box<[u8]> = key(b"bbb2");

        fn first_three(k: &[u8]) -> &[u8] {
            &k[..3]
        }

        let prefix_extractor = SliceTransform::create("first_three", first_three, None);

        let mut opts = Options::default();
        opts.create_if_missing(true);
        opts.set_prefix_extractor(prefix_extractor);

        let db = DB::open(&opts, &db_path).unwrap();

        assert!(db.put(&*a1, &*a1).is_ok());
        assert!(db.put(&*a2, &*a2).is_ok());
        assert!(db.put(&*b1, &*b1).is_ok());
        assert!(db.put(&*b2, &*b2).is_ok());

        fn cba(input: &[u8]) -> Box<[u8]> {
            input.to_vec().into_boxed_slice()
        }

        fn key(k: &[u8]) -> Box<[u8]> {
            k.to_vec().into_boxed_slice()
        }

        {
            let expected = vec![(cba(&a1), cba(&a1)), (cba(&a2), cba(&a2))];
            let a_iterator = db.prefix_iterator(b"aaa");
            assert_eq!(a_iterator.collect::<Vec<_>>(), expected)
        }

        {
            let expected = vec![(cba(&b1), cba(&b1)), (cba(&b2), cba(&b2))];
            let b_iterator = db.prefix_iterator(b"bbb");
            assert_eq!(b_iterator.collect::<Vec<_>>(), expected)
        }
    }
}