db-rs 0.3.6

fast, embedded, transactional, key value store
Documentation 
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use db_rs::utils::random_test_dir;
use db_rs::{Config, Db, LookupTable};
use db_rs_derive::Schema;
use std::fs::{remove_dir_all, OpenOptions};
use std::io::{Read, Write};
#[derive(Schema)]
struct TxTest {
    table: LookupTable<u8, String>,
}

#[test]
fn simple_tx() {
    let dir = &random_test_dir();
    drop(remove_dir_all(dir));
    let mut cfg = Config::in_folder(dir);
    cfg.fs_locks = false;

    let mut db = TxTest::init(cfg.clone()).unwrap();
    let tx = db.begin_transaction();
    db.table.insert(43, "test".to_string()).unwrap();
    assert_eq!(db.table.get().get(&43), Some(&"test".to_string()));

    {
        let db = TxTest::init(cfg.clone()).unwrap();
        assert_eq!(db.table.get().get(&43), None);
    }
    drop(tx);
    {
        let db = TxTest::init(cfg.clone()).unwrap();
        assert_eq!(db.table.get().get(&43), Some(&"test".to_string()));
    }

    drop(remove_dir_all(dir));
}

#[test]
fn tx_log_corrupt() {
    let dir = &random_test_dir();
    drop(remove_dir_all(dir));

    let mut db = TxTest::init(Config::in_folder(dir)).unwrap();
    for _ in 0..10 {
        db.table.insert(41, "test".to_string()).unwrap();
    }

    let tx = db.begin_transaction();
    for _ in 0..20 {
        db.table.insert(43, "test".to_string()).unwrap();
    }
    drop(tx);

    // cut out half the log
    let mut buf = vec![];
    let mut file = OpenOptions::new()
        .read(true)
        .write(true)
        .open(db.config().unwrap().db_location_v2().unwrap())
        .unwrap();
    file.read_to_end(&mut buf).unwrap();

    buf = buf[0..buf.len() / 2].to_vec();

    let mut file = OpenOptions::new()
        .create(true)
        .write(true)
        .truncate(true)
        .open(db.config().unwrap().db_location_v2().unwrap())
        .unwrap();
    file.write_all(&buf).unwrap();

    drop(db);
    let db = TxTest::init(Config::in_folder(dir)).unwrap();
    assert_eq!(db.table.get().get(&41), Some(&"test".to_string()));
    assert_eq!(db.table.get().get(&43), None);

    drop(remove_dir_all(dir));
}

#[test]
fn snapshot_inter() {
    let dir = &random_test_dir();
    drop(remove_dir_all(dir));

    let mut db = TxTest::init(Config::in_folder(dir)).unwrap();

    for i in 0..u8::MAX {
        db.table.insert(i, "test".to_string()).unwrap();
    }

    db.compact_log().unwrap();

    // cut out half the log
    let mut buf = vec![];
    let mut file = OpenOptions::new()
        .read(true)
        .write(true)
        .open(db.config().unwrap().db_location_v2().unwrap())
        .unwrap();
    file.read_to_end(&mut buf).unwrap();

    buf = buf[0..buf.len() / 2].to_vec();

    let mut file = OpenOptions::new()
        .create(true)
        .write(true)
        .truncate(true)
        .open(db.config().unwrap().db_location_v2().unwrap())
        .unwrap();
    file.write_all(&buf).unwrap();

    drop(db);
    let db = TxTest::init(Config::in_folder(dir)).unwrap();
    assert_eq!(db.table.get().get(&1), None);
    drop(remove_dir_all(dir));
}