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/// Read the reference counter for a key.
35fn read_counter(
36	db: &dyn KeyValueDB,
37	col: ColumnId,
38	key: &[u8],
39) -> error::Result<(Vec<u8>, Option<u32>)> {
40	let mut counter_key = key.to_vec();
41	counter_key.push(0);
42	Ok(match db.get(col, &counter_key).map_err(|e| error::DatabaseError(Box::new(e)))? {
43		Some(data) => {
44			let mut counter_data = [0; 4];
45			if data.len() != 4 {
46				return Err(error::DatabaseError(Box::new(std::io::Error::new(
47					std::io::ErrorKind::Other,
48					format!("Unexpected counter len {}", data.len()),
49				))))
50			}
51			counter_data.copy_from_slice(&data);
52			let counter = u32::from_le_bytes(counter_data);
53			(counter_key, Some(counter))
54		},
55		None => (counter_key, None),
56	})
57}
58
59/// Commit a transaction to a KeyValueDB.
60fn commit_impl<H: Clone + AsRef<[u8]>>(
61	db: &dyn KeyValueDB,
62	transaction: Transaction<H>,
63) -> error::Result<()> {
64	let mut tx = DBTransaction::new();
65	for change in transaction.0.into_iter() {
66		match change {
67			Change::Set(col, key, value) => tx.put_vec(col, &key, value),
68			Change::Remove(col, key) => tx.delete(col, &key),
69			Change::Store(col, key, value) => match read_counter(db, col, key.as_ref())? {
70				(counter_key, Some(mut counter)) => {
71					counter += 1;
72					tx.put(col, &counter_key, &counter.to_le_bytes());
73				},
74				(counter_key, None) => {
75					let d = 1u32.to_le_bytes();
76					tx.put(col, &counter_key, &d);
77					tx.put_vec(col, key.as_ref(), value);
78				},
79			},
80			Change::Reference(col, key) => {
81				if let (counter_key, Some(mut counter)) = read_counter(db, col, key.as_ref())? {
82					counter += 1;
83					tx.put(col, &counter_key, &counter.to_le_bytes());
84				}
85			},
86			Change::Release(col, key) => {
87				if let (counter_key, Some(mut counter)) = read_counter(db, col, key.as_ref())? {
88					counter -= 1;
89					if counter == 0 {
90						tx.delete(col, &counter_key);
91						tx.delete(col, key.as_ref());
92					} else {
93						tx.put(col, &counter_key, &counter.to_le_bytes());
94					}
95				}
96			},
97		}
98	}
99	db.write(tx).map_err(|e| error::DatabaseError(Box::new(e)))
100}
101
102/// Wrap generic kvdb-based database into a trait object that implements [`Database`].
103pub fn as_database<D, H>(db: D) -> std::sync::Arc<dyn Database<H>>
104where
105	D: KeyValueDB + 'static,
106	H: Clone + AsRef<[u8]>,
107{
108	std::sync::Arc::new(DbAdapter(db))
109}
110
111impl<D: KeyValueDB, H: Clone + AsRef<[u8]>> Database<H> for DbAdapter<D> {
112	fn commit(&self, transaction: Transaction<H>) -> error::Result<()> {
113		commit_impl(&self.0, transaction)
114	}
115
116	fn get(&self, col: ColumnId, key: &[u8]) -> Option<Vec<u8>> {
117		handle_err(self.0.get(col, key))
118	}
119
120	fn contains(&self, col: ColumnId, key: &[u8]) -> bool {
121		handle_err(self.0.has_key(col, key))
122	}
123}
124
125/// RocksDB-specific adapter that implements `optimize_db` via `force_compact`.
126#[cfg(feature = "rocksdb")]
127pub struct RocksDbAdapter(kvdb_rocksdb::Database);
128
129#[cfg(feature = "rocksdb")]
130impl<H: Clone + AsRef<[u8]>> Database<H> for RocksDbAdapter {
131	fn commit(&self, transaction: Transaction<H>) -> error::Result<()> {
132		commit_impl(&self.0, transaction)
133	}
134
135	fn get(&self, col: ColumnId, key: &[u8]) -> Option<Vec<u8>> {
136		handle_err(self.0.get(col, key))
137	}
138
139	fn contains(&self, col: ColumnId, key: &[u8]) -> bool {
140		handle_err(self.0.has_key(col, key))
141	}
142
143	fn optimize_db_col(&self, col: ColumnId) -> error::Result<()> {
144		self.0.force_compact(col).map_err(|e| error::DatabaseError(Box::new(e)))
145	}
146}
147
148/// Wrap RocksDB database into a trait object with `optimize_db` support.
149#[cfg(feature = "rocksdb")]
150pub fn as_rocksdb_database<H>(db: kvdb_rocksdb::Database) -> std::sync::Arc<dyn Database<H>>
151where
152	H: Clone + AsRef<[u8]>,
153{
154	std::sync::Arc::new(RocksDbAdapter(db))
155}
sp_database/kvdb.rs

sp_database/
kvdb.rs
