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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
// 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 MultiStore<D> {
db: D,
}
pub struct Iter<'i, I> {
iter: I,
phantom: PhantomData<&'i ()>,
}
impl<D> MultiStore<D>
where
D: BackendDatabase,
{
pub(crate) fn new(db: D) -> MultiStore<D> {
MultiStore { db }
}
/// Provides a cursor to all of the values for the duplicate entries that match this
/// key
pub fn get<'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_dup_of(k);
Ok(Iter {
iter,
phantom: PhantomData,
})
}
/// Provides the first value that matches this key
pub fn get_first<'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)
}
/// Insert a value at the specified key.
/// This put will allow duplicate entries. If you wish to have duplicate entries
/// rejected, use the `put_with_flags` function and specify NO_DUP_DATA
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())
}
pub fn put_with_flags<T, K>(
&self,
writer: &mut Writer<T>,
k: K,
v: &Value,
flags: T::Flags,
) -> EmptyResult
where
T: BackendRwTransaction<Database = D>,
K: AsRef<[u8]>,
{
writer.put(&self.db, &k, v, flags)
}
pub fn delete_all<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 delete<T, K>(&self, writer: &mut Writer<T>, k: K, v: &Value) -> EmptyResult
where
T: BackendRwTransaction<Database = D>,
K: AsRef<[u8]>,
{
writer.delete(&self.db, &k, Some(&v.to_bytes()?))
}
pub fn clear<T>(&self, writer: &mut Writer<T>) -> EmptyResult
where
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())),
}
}
}