1 files changed, 132 insertions, 0 deletions
diff --git a/third_party/rust/rkv/src/store/single.rs b/third_party/rust/rkv/src/store/single.rs
new file mode 100644
index 0000000000..c456e6aaa6
--- /dev/null
+++ b/third_party/rust/rkv/src/store/single.rs
@@ -0,0 +1,132 @@
+// 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::marker::PhantomData;
+
+use crate::{
+    backend::{BackendDatabase, BackendFlags, BackendIter, BackendRoCursor, BackendRwTransaction},
+    error::StoreError,
+    helpers::read_transform,
+    readwrite::{Readable, Writer},
+    value::Value,
+};
+
+type EmptyResult = Result<(), StoreError>;
+
+#[derive(Debug, Eq, PartialEq, Copy, Clone)]
+pub struct SingleStore<D> {
+    db: D,
+}
+
+pub struct Iter<'i, I> {
+    iter: I,
+    phantom: PhantomData<&'i ()>,
+}
+
+impl<D> SingleStore<D>
+where
+    D: BackendDatabase,
+{
+    pub(crate) fn new(db: D) -> SingleStore<D> {
+        SingleStore { db }
+    }
+
+    pub fn get<'r, R, K>(&self, reader: &'r R, k: K) -> Result<Option<Value<'r>>, StoreError>
+    where
+        R: Readable<'r, Database = D>,
+        K: AsRef<[u8]>,
+    {
+        reader.get(&self.db, &k)
+    }
+
+    // TODO: flags
+    pub fn put<T, K>(&self, writer: &mut Writer<T>, k: K, v: &Value) -> EmptyResult
+    where
+        T: BackendRwTransaction<Database = D>,
+        K: AsRef<[u8]>,
+    {
+        writer.put(&self.db, &k, v, T::Flags::empty())
+    }
+
+    #[cfg(not(feature = "db-dup-sort"))]
+    pub fn delete<T, K>(&self, writer: &mut Writer<T>, k: K) -> EmptyResult
+    where
+        T: BackendRwTransaction<Database = D>,
+        K: AsRef<[u8]>,
+    {
+        writer.delete(&self.db, &k)
+    }
+
+    #[cfg(feature = "db-dup-sort")]
+    pub fn delete<T, K>(&self, writer: &mut Writer<T>, k: K) -> EmptyResult
+    where
+        T: BackendRwTransaction<Database = D>,
+        K: AsRef<[u8]>,
+    {
+        writer.delete(&self.db, &k, None)
+    }
+
+    pub fn iter_start<'r, R, I, C>(&self, reader: &'r R) -> Result<Iter<'r, I>, StoreError>
+    where
+        R: Readable<'r, Database = D, RoCursor = C>,
+        I: BackendIter<'r>,
+        C: BackendRoCursor<'r, Iter = I>,
+    {
+        let cursor = reader.open_ro_cursor(&self.db)?;
+        let iter = cursor.into_iter();
+
+        Ok(Iter {
+            iter,
+            phantom: PhantomData,
+        })
+    }
+
+    pub fn iter_from<'r, R, I, C, K>(&self, reader: &'r R, k: K) -> Result<Iter<'r, I>, StoreError>
+    where
+        R: Readable<'r, Database = D, RoCursor = C>,
+        I: BackendIter<'r>,
+        C: BackendRoCursor<'r, Iter = I>,
+        K: AsRef<[u8]> + 'r,
+    {
+        let cursor = reader.open_ro_cursor(&self.db)?;
+        let iter = cursor.into_iter_from(k);
+
+        Ok(Iter {
+            iter,
+            phantom: PhantomData,
+        })
+    }
+
+    pub fn clear<T>(&self, writer: &mut Writer<T>) -> EmptyResult
+    where
+        D: BackendDatabase,
+        T: BackendRwTransaction<Database = D>,
+    {
+        writer.clear(&self.db)
+    }
+}
+
+impl<'i, I> Iterator for Iter<'i, I>
+where
+    I: BackendIter<'i>,
+{
+    type Item = Result<(&'i [u8], Value<'i>), StoreError>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        match self.iter.next() {
+            None => None,
+            Some(Ok((key, bytes))) => match read_transform(Ok(bytes)) {
+                Ok(val) => Some(Ok((key, val))),
+                Err(err) => Some(Err(err)),
+            },
+            Some(Err(err)) => Some(Err(err.into())),
+        }
+    }
+}