use core::ops::Bound;
use std::cell::Cell;
use std::collections::HashMap;
use std::sync::{Arc, RwLock};
use sled::transaction::{
ConflictableTransactionError, TransactionError, Transactional, TransactionalTree,
UnabortableTransactionError,
};
use crate::{
Db, Error, IDb, ITx, ITxFn, Result, TxError, TxFnResult, TxOpError, TxOpResult, TxResult,
TxValueIter, Value, ValueIter,
};
pub use sled;
// -- err
impl From<sled::Error> for Error {
fn from(e: sled::Error) -> Error {
Error(format!("Sled: {}", e).into())
}
}
impl From<sled::Error> for TxOpError {
fn from(e: sled::Error) -> TxOpError {
TxOpError(e.into())
}
}
// -- db
pub struct SledDb {
db: sled::Db,
trees: RwLock<(Vec<sled::Tree>, HashMap<String, usize>)>,
}
impl SledDb {
pub fn init(db: sled::Db) -> Db {
let s = Self {
db,
trees: RwLock::new((Vec::new(), HashMap::new())),
};
Db(Arc::new(s))
}
fn get_tree(&self, i: usize) -> Result<sled::Tree> {
self.trees
.read()
.unwrap()
.0
.get(i)
.cloned()
.ok_or_else(|| Error("invalid tree id".into()))
}
}
impl IDb for SledDb {
fn engine(&self) -> String {
"Sled".into()
}
fn open_tree(&self, name: &str) -> Result<usize> {
let mut trees = self.trees.write().unwrap();
if let Some(i) = trees.1.get(name) {
Ok(*i)
} else {
let tree = self.db.open_tree(name)?;
let i = trees.0.len();
trees.0.push(tree);
trees.1.insert(name.to_string(), i);
Ok(i)
}
}
fn list_trees(&self) -> Result<Vec<String>> {
let mut trees = vec![];
for name in self.db.tree_names() {
let name = std::str::from_utf8(&name)
.map_err(|e| Error(format!("{}", e).into()))?
.to_string();
if name != "__sled__default" {
trees.push(name);
}
}
Ok(trees)
}
// ----
fn get(&self, tree: usize, key: &[u8]) -> Result<Option<Value>> {
let tree = self.get_tree(tree)?;
let val = tree.get(key)?;
Ok(val.map(|x| x.to_vec()))
}
fn len(&self, tree: usize) -> Result<usize> {
let tree = self.get_tree(tree)?;
Ok(tree.len())
}
fn insert(&self, tree: usize, key: &[u8], value: &[u8]) -> Result<Option<Value>> {
let tree = self.get_tree(tree)?;
let old_val = tree.insert(key, value)?;
Ok(old_val.map(|x| x.to_vec()))
}
fn remove(&self, tree: usize, key: &[u8]) -> Result<Option<Value>> {
let tree = self.get_tree(tree)?;
let old_val = tree.remove(key)?;
Ok(old_val.map(|x| x.to_vec()))
}
fn clear(&self, tree: usize) -> Result<()> {
let tree = self.get_tree(tree)?;
tree.clear()?;
Ok(())
}
fn iter(&self, tree: usize) -> Result<ValueIter<'_>> {
let tree = self.get_tree(tree)?;
Ok(Box::new(tree.iter().map(|v| {
v.map(|(x, y)| (x.to_vec(), y.to_vec())).map_err(Into::into)
})))
}
fn iter_rev(&self, tree: usize) -> Result<ValueIter<'_>> {
let tree = self.get_tree(tree)?;
Ok(Box::new(tree.iter().rev().map(|v| {
v.map(|(x, y)| (x.to_vec(), y.to_vec())).map_err(Into::into)
})))
}
fn range<'r>(
&self,
tree: usize,
low: Bound<&'r [u8]>,
high: Bound<&'r [u8]>,
) -> Result<ValueIter<'_>> {
let tree = self.get_tree(tree)?;
Ok(Box::new(tree.range::<&'r [u8], _>((low, high)).map(|v| {
v.map(|(x, y)| (x.to_vec(), y.to_vec())).map_err(Into::into)
})))
}
fn range_rev<'r>(
&self,
tree: usize,
low: Bound<&'r [u8]>,
high: Bound<&'r [u8]>,
) -> Result<ValueIter<'_>> {
let tree = self.get_tree(tree)?;
Ok(Box::new(tree.range::<&'r [u8], _>((low, high)).rev().map(
|v| v.map(|(x, y)| (x.to_vec(), y.to_vec())).map_err(Into::into),
)))
}
// ----
fn transaction(&self, f: &dyn ITxFn) -> TxResult<(), ()> {
let trees = self.trees.read().unwrap();
let res = trees.0.transaction(|txtrees| {
let mut tx = SledTx {
trees: txtrees,
err: Cell::new(None),
};
match f.try_on(&mut tx) {
TxFnResult::Ok => {
assert!(tx.err.into_inner().is_none());
Ok(())
}
TxFnResult::Abort => {
assert!(tx.err.into_inner().is_none());
Err(ConflictableTransactionError::Abort(()))
}
TxFnResult::DbErr => {
let e = tx.err.into_inner().expect("No DB error");
Err(e.into())
}
}
});
match res {
Ok(()) => Ok(()),
Err(TransactionError::Abort(())) => Err(TxError::Abort(())),
Err(TransactionError::Storage(s)) => Err(TxError::Db(s.into())),
}
}
}
// ----
struct SledTx<'a> {
trees: &'a [TransactionalTree],
err: Cell<Option<UnabortableTransactionError>>,
}
impl<'a> SledTx<'a> {
fn get_tree(&self, i: usize) -> TxOpResult<&TransactionalTree> {
self.trees.get(i).ok_or_else(|| {
TxOpError(Error(
"invalid tree id (it might have been openned after the transaction started)".into(),
))
})
}
fn save_error<R>(
&self,
v: std::result::Result<R, UnabortableTransactionError>,
) -> TxOpResult<R> {
match v {
Ok(x) => Ok(x),
Err(e) => {
let txt = format!("{}", e);
self.err.set(Some(e));
Err(TxOpError(Error(txt.into())))
}
}
}
}
impl<'a> ITx for SledTx<'a> {
fn get(&self, tree: usize, key: &[u8]) -> TxOpResult<Option<Value>> {
let tree = self.get_tree(tree)?;
let tmp = self.save_error(tree.get(key))?;
Ok(tmp.map(|x| x.to_vec()))
}
fn len(&self, _tree: usize) -> TxOpResult<usize> {
unimplemented!(".len() in transaction not supported with Sled backend")
}
fn insert(&mut self, tree: usize, key: &[u8], value: &[u8]) -> TxOpResult<Option<Value>> {
let tree = self.get_tree(tree)?;
let old_val = self.save_error(tree.insert(key, value))?;
Ok(old_val.map(|x| x.to_vec()))
}
fn remove(&mut self, tree: usize, key: &[u8]) -> TxOpResult<Option<Value>> {
let tree = self.get_tree(tree)?;
let old_val = self.save_error(tree.remove(key))?;
Ok(old_val.map(|x| x.to_vec()))
}
fn iter(&self, _tree: usize) -> TxOpResult<TxValueIter<'_>> {
unimplemented!("Iterators in transactions not supported with Sled backend");
}
fn iter_rev(&self, _tree: usize) -> TxOpResult<TxValueIter<'_>> {
unimplemented!("Iterators in transactions not supported with Sled backend");
}
fn range<'r>(
&self,
_tree: usize,
_low: Bound<&'r [u8]>,
_high: Bound<&'r [u8]>,
) -> TxOpResult<TxValueIter<'_>> {
unimplemented!("Iterators in transactions not supported with Sled backend");
}
fn range_rev<'r>(
&self,
_tree: usize,
_low: Bound<&'r [u8]>,
_high: Bound<&'r [u8]>,
) -> TxOpResult<TxValueIter<'_>> {
unimplemented!("Iterators in transactions not supported with Sled backend");
}
}
