mentat/tolstoy/src/tx_mapper.rs

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// Copyright 2018 Mozilla
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not use
// this file except in compliance with the License. You may obtain a copy of the
// License at http://www.apache.org/licenses/LICENSE-2.0
// Unless required by applicable law or agreed to in writing, software distributed
// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
// CONDITIONS OF ANY KIND, either express or implied. See the License for the
// specific language governing permissions and limitations under the License.
use std::collections::HashMap;
use rusqlite;
use uuid::Uuid;
use core_traits::{
Entid,
};
use tolstoy_traits::errors::{
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TolstoyError,
Result,
};
// Exposes a tx<->uuid mapping interface.
pub struct TxMapper {}
impl TxMapper {
pub fn set_bulk(db_tx: &mut rusqlite::Transaction, tx_uuid_map: &HashMap<Entid, Uuid>) -> Result<()> {
let mut stmt = db_tx.prepare_cached(
"INSERT OR REPLACE INTO tolstoy_tu (tx, uuid) VALUES (?, ?)"
)?;
for (tx, uuid) in tx_uuid_map.iter() {
let uuid_bytes = uuid.as_bytes().to_vec();
stmt.execute(&[tx, &uuid_bytes])?;
}
Ok(())
}
// TODO for when we're downloading, right?
pub fn get_or_set_uuid_for_tx(db_tx: &mut rusqlite::Transaction, tx: Entid) -> Result<Uuid> {
match TxMapper::get(db_tx, tx)? {
Some(uuid) => Ok(uuid),
None => {
let uuid = Uuid::new_v4();
let uuid_bytes = uuid.as_bytes().to_vec();
db_tx.execute("INSERT INTO tolstoy_tu (tx, uuid) VALUES (?, ?)", &[&tx, &uuid_bytes])?;
return Ok(uuid);
}
}
}
pub fn get_tx_for_uuid(db_tx: &rusqlite::Transaction, uuid: &Uuid) -> Result<Option<Entid>> {
let mut stmt = db_tx.prepare_cached(
"SELECT tx FROM tolstoy_tu WHERE uuid = ?"
)?;
let uuid_bytes = uuid.as_bytes().to_vec();
let results = stmt.query_map(&[&uuid_bytes], |r| r.get(0))?;
let mut txs = vec![];
txs.extend(results);
if txs.len() == 0 {
return Ok(None);
} else if txs.len() > 1 {
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bail!(TolstoyError::TxIncorrectlyMapped(txs.len()));
}
Ok(Some(txs.remove(0)?))
}
pub fn get(db_tx: &rusqlite::Transaction, tx: Entid) -> Result<Option<Uuid>> {
let mut stmt = db_tx.prepare_cached(
"SELECT uuid FROM tolstoy_tu WHERE tx = ?"
)?;
let results = stmt.query_and_then(&[&tx], |r| -> Result<Uuid>{
let bytes: Vec<u8> = r.get(0);
Uuid::from_bytes(bytes.as_slice()).map_err(|e| e.into())
})?;
let mut uuids = vec![];
uuids.extend(results);
if uuids.len() == 0 {
return Ok(None);
} else if uuids.len() > 1 {
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bail!(TolstoyError::TxIncorrectlyMapped(uuids.len()));
}
Ok(Some(uuids.remove(0)?))
}
}
#[cfg(test)]
pub mod tests {
use super::*;
use schema;
#[test]
fn test_getters() {
let mut conn = schema::tests::setup_conn();
let mut tx = conn.transaction().expect("db tx");
assert_eq!(None, TxMapper::get(&mut tx, 1).expect("success"));
let set_uuid = TxMapper::get_or_set_uuid_for_tx(&mut tx, 1).expect("success");
assert_eq!(Some(set_uuid), TxMapper::get(&mut tx, 1).expect("success"));
}
#[test]
fn test_bulk_setter() {
let mut conn = schema::tests::setup_conn();
let mut tx = conn.transaction().expect("db tx");
let mut map = HashMap::new();
TxMapper::set_bulk(&mut tx, &map).expect("empty map success");
let uuid1 = Uuid::new_v4();
let uuid2 = Uuid::new_v4();
map.insert(1, uuid1);
map.insert(2, uuid2);
TxMapper::set_bulk(&mut tx, &map).expect("map success");
assert_eq!(Some(uuid1), TxMapper::get(&mut tx, 1).expect("success"));
assert_eq!(Some(uuid2), TxMapper::get(&mut tx, 2).expect("success"));
// Now let's replace one of mappings.
map.remove(&1);
let new_uuid2 = Uuid::new_v4();
map.insert(2, new_uuid2);
TxMapper::set_bulk(&mut tx, &map).expect("map success");
assert_eq!(Some(uuid1), TxMapper::get(&mut tx, 1).expect("success"));
assert_eq!(Some(new_uuid2), TxMapper::get(&mut tx, 2).expect("success"));
}
}