use core::ops::Bound;
use core::ptr::NonNull;
use std::collections::HashMap;
use std::convert::TryInto;
use std::sync::{Arc, RwLock};
use heed::types::ByteSlice;
use heed::{BytesDecode, Env, RoTxn, RwTxn, UntypedDatabase as Database};
use crate::{
Db, Error, IDb, ITx, ITxFn, Result, TxError, TxFnResult, TxOpError, TxOpResult, TxResult,
TxValueIter, Value, ValueIter,
};
pub use heed;
impl From<heed::Error> for Error {
fn from(e: heed::Error) -> Error {
Error(format!("LMDB: {}", e).into())
}
}
impl From<heed::Error> for TxOpError {
fn from(e: heed::Error) -> TxOpError {
TxOpError(e.into())
}
}
pub struct LmdbDb {
db: heed::Env,
trees: RwLock<(Vec<Database>, HashMap<String, usize>)>,
}
impl LmdbDb {
pub fn init(db: Env) -> Db {
let s = Self {
db,
trees: RwLock::new((Vec::new(), HashMap::new())),
};
Db(Arc::new(s))
}
fn get_tree(&self, i: usize) -> Result<Database> {
self.trees
.read()
.unwrap()
.0
.get(i)
.cloned()
.ok_or_else(|| Error("invalid tree id".into()))
}
}
impl IDb for LmdbDb {
fn engine(&self) -> String {
"LMDB (using Heed crate)".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.create_database(Some(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 tree0 = match self.db.open_database::<heed::types::Str, ByteSlice>(None)? {
Some(x) => x,
None => return Ok(vec![]),
};
let mut ret = vec![];
let tx = self.db.read_txn()?;
for item in tree0.iter(&tx)? {
let (tree_name, _) = item?;
ret.push(tree_name.to_string());
}
drop(tx);
let mut ret2 = vec![];
for tree_name in ret {
if self
.db
.open_database::<ByteSlice, ByteSlice>(Some(&tree_name))?
.is_some()
{
ret2.push(tree_name);
}
}
Ok(ret2)
}
fn get(&self, tree: usize, key: &[u8]) -> Result<Option<Value>> {
let tree = self.get_tree(tree)?;
let tx = self.db.read_txn()?;
let val = tree.get(&tx, key)?;
match val {
None => Ok(None),
Some(v) => Ok(Some(v.to_vec())),
}
}
fn len(&self, tree: usize) -> Result<usize> {
let tree = self.get_tree(tree)?;
let tx = self.db.read_txn()?;
Ok(tree.len(&tx)?.try_into().unwrap())
}
fn fast_len(&self, tree: usize) -> Result<Option<usize>> {
Ok(Some(self.len(tree)?))
}
fn insert(&self, tree: usize, key: &[u8], value: &[u8]) -> Result<Option<Value>> {
let tree = self.get_tree(tree)?;
let mut tx = self.db.write_txn()?;
let old_val = tree.get(&tx, key)?.map(Vec::from);
tree.put(&mut tx, key, value)?;
tx.commit()?;
Ok(old_val)
}
fn remove(&self, tree: usize, key: &[u8]) -> Result<Option<Value>> {
let tree = self.get_tree(tree)?;
let mut tx = self.db.write_txn()?;
let old_val = tree.get(&tx, key)?.map(Vec::from);
tree.delete(&mut tx, key)?;
tx.commit()?;
Ok(old_val)
}
fn clear(&self, tree: usize) -> Result<()> {
let tree = self.get_tree(tree)?;
let mut tx = self.db.write_txn()?;
tree.clear(&mut tx)?;
tx.commit()?;
Ok(())
}
fn iter(&self, tree: usize) -> Result<ValueIter<'_>> {
let tree = self.get_tree(tree)?;
let tx = self.db.read_txn()?;
TxAndIterator::make(tx, |tx| Ok(tree.iter(tx)?))
}
fn iter_rev(&self, tree: usize) -> Result<ValueIter<'_>> {
let tree = self.get_tree(tree)?;
let tx = self.db.read_txn()?;
TxAndIterator::make(tx, |tx| Ok(tree.rev_iter(tx)?))
}
fn range<'r>(
&self,
tree: usize,
low: Bound<&'r [u8]>,
high: Bound<&'r [u8]>,
) -> Result<ValueIter<'_>> {
let tree = self.get_tree(tree)?;
let tx = self.db.read_txn()?;
TxAndIterator::make(tx, |tx| Ok(tree.range(tx, &(low, high))?))
}
fn range_rev<'r>(
&self,
tree: usize,
low: Bound<&'r [u8]>,
high: Bound<&'r [u8]>,
) -> Result<ValueIter<'_>> {
let tree = self.get_tree(tree)?;
let tx = self.db.read_txn()?;
TxAndIterator::make(tx, |tx| Ok(tree.rev_range(tx, &(low, high))?))
}
fn transaction(&self, f: &dyn ITxFn) -> TxResult<(), ()> {
let trees = self.trees.read().unwrap();
let mut tx = LmdbTx {
trees: &trees.0[..],
tx: self
.db
.write_txn()
.map_err(Error::from)
.map_err(TxError::Db)?,
};
let res = f.try_on(&mut tx);
match res {
TxFnResult::Ok => {
tx.tx.commit().map_err(Error::from).map_err(TxError::Db)?;
Ok(())
}
TxFnResult::Abort => {
tx.tx.abort().map_err(Error::from).map_err(TxError::Db)?;
Err(TxError::Abort(()))
}
TxFnResult::DbErr => {
tx.tx.abort().map_err(Error::from).map_err(TxError::Db)?;
Err(TxError::Db(Error(
"(this message will be discarded)".into(),
)))
}
}
}
}
struct LmdbTx<'a> {
trees: &'a [Database],
tx: RwTxn<'a, 'a>,
}
impl<'a> LmdbTx<'a> {
fn get_tree(&self, i: usize) -> TxOpResult<&Database> {
self.trees.get(i).ok_or_else(|| {
TxOpError(Error(
"invalid tree id (it might have been openned after the transaction started)".into(),
))
})
}
}
impl<'a> ITx for LmdbTx<'a> {
fn get(&self, tree: usize, key: &[u8]) -> TxOpResult<Option<Value>> {
let tree = self.get_tree(tree)?;
match tree.get(&self.tx, key)? {
Some(v) => Ok(Some(v.to_vec())),
None => Ok(None),
}
}
fn len(&self, _tree: usize) -> TxOpResult<usize> {
unimplemented!(".len() in transaction not supported with LMDB backend")
}
fn insert(&mut self, tree: usize, key: &[u8], value: &[u8]) -> TxOpResult<Option<Value>> {
let tree = *self.get_tree(tree)?;
let old_val = tree.get(&self.tx, key)?.map(Vec::from);
tree.put(&mut self.tx, key, value)?;
Ok(old_val)
}
fn remove(&mut self, tree: usize, key: &[u8]) -> TxOpResult<Option<Value>> {
let tree = *self.get_tree(tree)?;
let old_val = tree.get(&self.tx, key)?.map(Vec::from);
tree.delete(&mut self.tx, key)?;
Ok(old_val)
}
fn iter(&self, _tree: usize) -> TxOpResult<TxValueIter<'_>> {
unimplemented!("Iterators in transactions not supported with LMDB backend");
}
fn iter_rev(&self, _tree: usize) -> TxOpResult<TxValueIter<'_>> {
unimplemented!("Iterators in transactions not supported with LMDB backend");
}
fn range<'r>(
&self,
_tree: usize,
_low: Bound<&'r [u8]>,
_high: Bound<&'r [u8]>,
) -> TxOpResult<TxValueIter<'_>> {
unimplemented!("Iterators in transactions not supported with LMDB 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 LMDB backend");
}
}
type IteratorItem<'a> = heed::Result<(
<ByteSlice as BytesDecode<'a>>::DItem,
<ByteSlice as BytesDecode<'a>>::DItem,
)>;
struct TxAndIterator<'a, I>
where
I: Iterator<Item = IteratorItem<'a>> + 'a,
{
tx: RoTxn<'a>,
iter: Option<I>,
}
impl<'a, I> TxAndIterator<'a, I>
where
I: Iterator<Item = IteratorItem<'a>> + 'a,
{
fn make<F>(tx: RoTxn<'a>, iterfun: F) -> Result<ValueIter<'a>>
where
F: FnOnce(&'a RoTxn<'a>) -> Result<I>,
{
let mut res = TxAndIterator { tx, iter: None };
let tx = unsafe { NonNull::from(&res.tx).as_ref() };
res.iter = Some(iterfun(tx)?);
Ok(Box::new(res))
}
}
impl<'a, I> Drop for TxAndIterator<'a, I>
where
I: Iterator<Item = IteratorItem<'a>> + 'a,
{
fn drop(&mut self) {
drop(self.iter.take());
}
}
impl<'a, I> Iterator for TxAndIterator<'a, I>
where
I: Iterator<Item = IteratorItem<'a>> + 'a,
{
type Item = Result<(Value, Value)>;
fn next(&mut self) -> Option<Self::Item> {
match self.iter.as_mut().unwrap().next() {
None => None,
Some(Err(e)) => Some(Err(e.into())),
Some(Ok((k, v))) => Some(Ok((k.to_vec(), v.to_vec()))),
}
}
}
#[cfg(target_pointer_width = "64")]
pub fn recommended_map_size() -> usize {
1usize << 40
}
#[cfg(target_pointer_width = "32")]
pub fn recommended_map_size() -> usize {
tracing::warn!("LMDB is not recommended on 32-bit systems, database size will be limited");
1usize << 30
}