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154 lines
4.0 KiB
154 lines
4.0 KiB
// Copyright 2018-2019 Mozilla
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//
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// Licensed under the Apache License, Version 2.0 (the "License"); you may not use
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// this file except in compliance with the License. You may obtain a copy of the
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// License at http://www.apache.org/licenses/LICENSE-2.0
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// Unless required by applicable law or agreed to in writing, software distributed
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// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
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// CONDITIONS OF ANY KIND, either express or implied. See the License for the
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// specific language governing permissions and limitations under the License.
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use crate::{
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backend::{
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BackendDatabase, BackendRoCursor, BackendRoCursorTransaction, BackendRoTransaction,
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BackendRwCursorTransaction, BackendRwTransaction,
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},
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error::StoreError,
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helpers::read_transform,
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value::Value,
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};
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pub struct Reader<T>(T);
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pub struct Writer<T>(T);
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pub trait Readable<'r> {
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type Database: BackendDatabase;
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type RoCursor: BackendRoCursor<'r>;
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fn get<K>(&'r self, db: &Self::Database, k: &K) -> Result<Option<Value<'r>>, StoreError>
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where
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K: AsRef<[u8]>;
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fn open_ro_cursor(&'r self, db: &Self::Database) -> Result<Self::RoCursor, StoreError>;
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}
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impl<'r, T> Readable<'r> for Reader<T>
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where
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T: BackendRoCursorTransaction<'r>,
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{
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type Database = T::Database;
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type RoCursor = T::RoCursor;
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fn get<K>(&'r self, db: &T::Database, k: &K) -> Result<Option<Value<'r>>, StoreError>
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where
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K: AsRef<[u8]>,
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{
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let bytes = self.0.get(db, k.as_ref()).map_err(|e| e.into());
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match read_transform(bytes).map(Some) {
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Err(StoreError::KeyValuePairNotFound) => Ok(None),
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result => result,
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}
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}
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fn open_ro_cursor(&'r self, db: &T::Database) -> Result<T::RoCursor, StoreError> {
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self.0.open_ro_cursor(db).map_err(|e| e.into())
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}
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}
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impl<T> Reader<T> {
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pub(crate) fn new(txn: T) -> Reader<T> {
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Reader(txn)
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}
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}
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impl<T> Reader<T>
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where
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T: BackendRoTransaction,
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{
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pub fn abort(self) {
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self.0.abort();
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}
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}
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impl<'r, T> Readable<'r> for Writer<T>
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where
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T: BackendRwCursorTransaction<'r>,
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{
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type Database = T::Database;
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type RoCursor = T::RoCursor;
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fn get<K>(&'r self, db: &T::Database, k: &K) -> Result<Option<Value<'r>>, StoreError>
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where
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K: AsRef<[u8]>,
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{
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let bytes = self.0.get(db, k.as_ref()).map_err(|e| e.into());
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match read_transform(bytes).map(Some) {
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Err(StoreError::KeyValuePairNotFound) => Ok(None),
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result => result,
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}
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}
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fn open_ro_cursor(&'r self, db: &T::Database) -> Result<T::RoCursor, StoreError> {
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self.0.open_ro_cursor(db).map_err(|e| e.into())
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}
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}
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impl<T> Writer<T> {
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pub(crate) fn new(txn: T) -> Writer<T> {
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Writer(txn)
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}
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}
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impl<T> Writer<T>
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where
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T: BackendRwTransaction,
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{
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pub fn commit(self) -> Result<(), StoreError> {
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self.0.commit().map_err(|e| e.into())
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}
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pub fn abort(self) {
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self.0.abort();
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}
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pub(crate) fn put<K>(
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&mut self,
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db: &T::Database,
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k: &K,
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v: &Value,
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flags: T::Flags,
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) -> Result<(), StoreError>
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where
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K: AsRef<[u8]>,
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{
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// TODO: don't allocate twice.
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self.0
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.put(db, k.as_ref(), &v.to_bytes()?, flags)
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.map_err(|e| e.into())
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}
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#[cfg(not(feature = "db-dup-sort"))]
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pub(crate) fn delete<K>(&mut self, db: &T::Database, k: &K) -> Result<(), StoreError>
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where
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K: AsRef<[u8]>,
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{
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self.0.del(db, k.as_ref()).map_err(|e| e.into())
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}
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#[cfg(feature = "db-dup-sort")]
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pub(crate) fn delete<K>(
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&mut self,
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db: &T::Database,
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k: &K,
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v: Option<&[u8]>,
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) -> Result<(), StoreError>
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where
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K: AsRef<[u8]>,
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{
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self.0.del(db, k.as_ref(), v).map_err(|e| e.into())
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}
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pub(crate) fn clear(&mut self, db: &T::Database) -> Result<(), StoreError> {
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self.0.clear_db(db).map_err(|e| e.into())
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}
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}
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