sp_database/
kvdb.rs

1// This file is part of Substrate.
2
3// Copyright (C) Parity Technologies (UK) Ltd.
4// SPDX-License-Identifier: Apache-2.0
5
6// Licensed under the Apache License, Version 2.0 (the "License");
7// you may not use this file except in compliance with the License.
8// You may obtain a copy of the License at
9//
10// 	http://www.apache.org/licenses/LICENSE-2.0
11//
12// Unless required by applicable law or agreed to in writing, software
13// distributed under the License is distributed on an "AS IS" BASIS,
14// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15// See the License for the specific language governing permissions and
16// limitations under the License.
17
18/// A wrapper around `kvdb::Database` that implements `sp_database::Database` trait
19use ::kvdb::{DBTransaction, KeyValueDB};
20
21use crate::{error, Change, ColumnId, Database, Transaction};
22
23struct DbAdapter<D: KeyValueDB + 'static>(D);
24
25fn handle_err<T>(result: std::io::Result<T>) -> T {
26	match result {
27		Ok(r) => r,
28		Err(e) => {
29			panic!("Critical database error: {:?}", e);
30		},
31	}
32}
33
34/// Wrap RocksDb database into a trait object that implements `sp_database::Database`
35pub fn as_database<D, H>(db: D) -> std::sync::Arc<dyn Database<H>>
36where
37	D: KeyValueDB + 'static,
38	H: Clone + AsRef<[u8]>,
39{
40	std::sync::Arc::new(DbAdapter(db))
41}
42
43impl<D: KeyValueDB> DbAdapter<D> {
44	// Returns counter key and counter value if it exists.
45	fn read_counter(&self, col: ColumnId, key: &[u8]) -> error::Result<(Vec<u8>, Option<u32>)> {
46		// Add a key suffix for the counter
47		let mut counter_key = key.to_vec();
48		counter_key.push(0);
49		Ok(match self.0.get(col, &counter_key).map_err(|e| error::DatabaseError(Box::new(e)))? {
50			Some(data) => {
51				let mut counter_data = [0; 4];
52				if data.len() != 4 {
53					return Err(error::DatabaseError(Box::new(std::io::Error::new(
54						std::io::ErrorKind::Other,
55						format!("Unexpected counter len {}", data.len()),
56					))))
57				}
58				counter_data.copy_from_slice(&data);
59				let counter = u32::from_le_bytes(counter_data);
60				(counter_key, Some(counter))
61			},
62			None => (counter_key, None),
63		})
64	}
65}
66
67impl<D: KeyValueDB, H: Clone + AsRef<[u8]>> Database<H> for DbAdapter<D> {
68	fn commit(&self, transaction: Transaction<H>) -> error::Result<()> {
69		let mut tx = DBTransaction::new();
70		for change in transaction.0.into_iter() {
71			match change {
72				Change::Set(col, key, value) => tx.put_vec(col, &key, value),
73				Change::Remove(col, key) => tx.delete(col, &key),
74				Change::Store(col, key, value) => match self.read_counter(col, key.as_ref())? {
75					(counter_key, Some(mut counter)) => {
76						counter += 1;
77						tx.put(col, &counter_key, &counter.to_le_bytes());
78					},
79					(counter_key, None) => {
80						let d = 1u32.to_le_bytes();
81						tx.put(col, &counter_key, &d);
82						tx.put_vec(col, key.as_ref(), value);
83					},
84				},
85				Change::Reference(col, key) => {
86					if let (counter_key, Some(mut counter)) =
87						self.read_counter(col, key.as_ref())?
88					{
89						counter += 1;
90						tx.put(col, &counter_key, &counter.to_le_bytes());
91					}
92				},
93				Change::Release(col, key) => {
94					if let (counter_key, Some(mut counter)) =
95						self.read_counter(col, key.as_ref())?
96					{
97						counter -= 1;
98						if counter == 0 {
99							tx.delete(col, &counter_key);
100							tx.delete(col, key.as_ref());
101						} else {
102							tx.put(col, &counter_key, &counter.to_le_bytes());
103						}
104					}
105				},
106			}
107		}
108		self.0.write(tx).map_err(|e| error::DatabaseError(Box::new(e)))
109	}
110
111	fn get(&self, col: ColumnId, key: &[u8]) -> Option<Vec<u8>> {
112		handle_err(self.0.get(col, key))
113	}
114
115	fn contains(&self, col: ColumnId, key: &[u8]) -> bool {
116		handle_err(self.0.has_key(col, key))
117	}
118}
sp_database/kvdb.rs

sp_database/
kvdb.rs
