Source code
Revision control
Copy as Markdown
Other Tools
// Copyright 2018-2019 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
// 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 crate::{
backend::{
BackendDatabase, BackendRoCursor, BackendRoCursorTransaction, BackendRoTransaction,
BackendRwCursorTransaction, BackendRwTransaction,
},
error::StoreError,
helpers::read_transform,
value::Value,
};
pub struct Reader<T>(T);
pub struct Writer<T>(T);
pub trait Readable<'r> {
type Database: BackendDatabase;
type RoCursor: BackendRoCursor<'r>;
fn get<K>(&'r self, db: &Self::Database, k: &K) -> Result<Option<Value<'r>>, StoreError>
where
K: AsRef<[u8]>;
fn open_ro_cursor(&'r self, db: &Self::Database) -> Result<Self::RoCursor, StoreError>;
}
impl<'r, T> Readable<'r> for Reader<T>
where
T: BackendRoCursorTransaction<'r>,
{
type Database = T::Database;
type RoCursor = T::RoCursor;
fn get<K>(&'r self, db: &T::Database, k: &K) -> Result<Option<Value<'r>>, StoreError>
where
K: AsRef<[u8]>,
{
let bytes = self.0.get(db, k.as_ref()).map_err(|e| e.into());
match read_transform(bytes).map(Some) {
Err(StoreError::KeyValuePairNotFound) => Ok(None),
result => result,
}
}
fn open_ro_cursor(&'r self, db: &T::Database) -> Result<T::RoCursor, StoreError> {
self.0.open_ro_cursor(db).map_err(|e| e.into())
}
}
impl<T> Reader<T> {
pub(crate) fn new(txn: T) -> Reader<T> {
Reader(txn)
}
}
impl<T> Reader<T>
where
T: BackendRoTransaction,
{
pub fn abort(self) {
self.0.abort();
}
}
impl<'r, T> Readable<'r> for Writer<T>
where
T: BackendRwCursorTransaction<'r>,
{
type Database = T::Database;
type RoCursor = T::RoCursor;
fn get<K>(&'r self, db: &T::Database, k: &K) -> Result<Option<Value<'r>>, StoreError>
where
K: AsRef<[u8]>,
{
let bytes = self.0.get(db, k.as_ref()).map_err(|e| e.into());
match read_transform(bytes).map(Some) {
Err(StoreError::KeyValuePairNotFound) => Ok(None),
result => result,
}
}
fn open_ro_cursor(&'r self, db: &T::Database) -> Result<T::RoCursor, StoreError> {
self.0.open_ro_cursor(db).map_err(|e| e.into())
}
}
impl<T> Writer<T> {
pub(crate) fn new(txn: T) -> Writer<T> {
Writer(txn)
}
}
impl<T> Writer<T>
where
T: BackendRwTransaction,
{
pub fn commit(self) -> Result<(), StoreError> {
self.0.commit().map_err(|e| e.into())
}
pub fn abort(self) {
self.0.abort();
}
pub(crate) fn put<K>(
&mut self,
db: &T::Database,
k: &K,
v: &Value,
flags: T::Flags,
) -> Result<(), StoreError>
where
K: AsRef<[u8]>,
{
// TODO: don't allocate twice.
self.0
.put(db, k.as_ref(), &v.to_bytes()?, flags)
.map_err(|e| e.into())
}
#[cfg(not(feature = "db-dup-sort"))]
pub(crate) fn delete<K>(&mut self, db: &T::Database, k: &K) -> Result<(), StoreError>
where
K: AsRef<[u8]>,
{
self.0.del(db, k.as_ref()).map_err(|e| e.into())
}
#[cfg(feature = "db-dup-sort")]
pub(crate) fn delete<K>(
&mut self,
db: &T::Database,
k: &K,
v: Option<&[u8]>,
) -> Result<(), StoreError>
where
K: AsRef<[u8]>,
{
self.0.del(db, k.as_ref(), v).map_err(|e| e.into())
}
pub(crate) fn clear(&mut self, db: &T::Database) -> Result<(), StoreError> {
self.0.clear_db(db).map_err(|e| e.into())
}
}