79 lines
2.3 KiB
Rust
79 lines
2.3 KiB
Rust
// Copyright 2015-2017 Parity Technologies (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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use std::collections::VecDeque;
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use parking_lot::{Mutex, Condvar};
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#[derive(Default)]
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/// General deque-based tasks queue.
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pub struct TasksQueue<Task: Clone> {
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/// Service event.
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service_event: Condvar,
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/// Service tasks queue.
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service_tasks: Mutex<VecDeque<Task>>,
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}
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impl<Task> TasksQueue<Task> where Task: Clone {
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/// Create new tasks queue.
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pub fn new() -> Self {
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TasksQueue {
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service_event: Condvar::new(),
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service_tasks: Mutex::new(VecDeque::new()),
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}
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}
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#[cfg(test)]
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/// Get current tasks snapshot.
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pub fn snapshot(&self) -> VecDeque<Task> {
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self.service_tasks.lock().clone()
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}
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/// Push task to the front of queue.
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pub fn push_front(&self, task: Task) {
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let mut service_tasks = self.service_tasks.lock();
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service_tasks.push_front(task);
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self.service_event.notify_all();
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}
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/// Push task to the back of queue.
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pub fn push(&self, task: Task) {
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let mut service_tasks = self.service_tasks.lock();
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service_tasks.push_back(task);
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self.service_event.notify_all();
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}
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/// Push task to the back of queue.
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pub fn push_many<I: Iterator<Item=Task>>(&self, tasks: I) {
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let mut service_tasks = self.service_tasks.lock();
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let previous_len = service_tasks.len();
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service_tasks.extend(tasks);
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if service_tasks.len() != previous_len {
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self.service_event.notify_all();
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}
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}
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/// Wait for new task (task is removed from the front of queue).
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pub fn wait(&self) -> Task {
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let mut service_tasks = self.service_tasks.lock();
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if service_tasks.is_empty() {
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self.service_event.wait(&mut service_tasks);
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}
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service_tasks.pop_front()
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.expect("service_event is only fired when there are new tasks; qed")
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}
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}
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