62 lines
1.8 KiB
Rust
62 lines
1.8 KiB
Rust
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// Copyright 2015, 2016 Ethcore (UK) Ltd.
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// This file is part of Parity.
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// Parity is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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// Parity is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License
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// along with Parity. If not, see <http://www.gnu.org/licenses/>.
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//! Extras db utils.
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use util::{H264, DBTransaction, Database};
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use util::rlp::{encode, Encodable, decode, Decodable};
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/// Should be used to get database key associated with given value.
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pub trait Key<T> {
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/// Returns db key.
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fn key(&self) -> H264;
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}
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/// Should be used to write value into database.
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pub trait Writable {
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/// Writes key into database.
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fn write<T>(&self, key: &Key<T>, value: &T) where T: Encodable;
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}
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/// Should be used to read values from database.
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pub trait Readable {
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/// Returns value for given key.
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fn read<T>(&self, key: &Key<T>) -> Option<T> where T: Decodable;
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/// Returns true if given value exists.
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fn exists<T>(&self, key: &Key<T>) -> bool;
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}
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impl Writable for DBTransaction {
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fn write<T>(&self, key: &Key<T>, value: &T) where T: Encodable {
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self.put(&key.key(), &encode(value))
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.expect("db put failed");
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}
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}
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impl Readable for Database {
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fn read<T>(&self, key: &Key<T>) -> Option<T> where T: Decodable {
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self.get(&key.key())
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.expect("db get failed")
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.map(|v| decode(&v))
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}
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fn exists<T>(&self, key: &Key<T>) -> bool {
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self.get(&key.key())
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.expect("db get failed")
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.is_some()
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}
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}
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