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// This file is part of Substrate.
// Copyright (C) Parity Technologies (UK) Ltd.
// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
//! Produce opaque sequential IDs.
/// A Sequence of IDs.
#[derive(Debug, Default)]
// The `Clone` trait is intentionally not defined on this type.
pub struct IDSequence {
next_id: u64,
}
/// A Sequential ID.
///
/// Its integer value is intentionally not public: it is supposed to be instantiated from within
/// this module only.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord)]
pub struct SeqID(u64);
impl std::fmt::Display for SeqID {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
write!(f, "{}", self.0)
}
}
impl IDSequence {
/// Create a new ID-sequence.
pub fn new() -> Self {
Default::default()
}
/// Obtain another ID from this sequence.
pub fn next_id(&mut self) -> SeqID {
let id = SeqID(self.next_id);
self.next_id += 1;
id
}
}