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// From c3po, https://github.com/withoutboats/c3po/blob/08a6fde00c6506bacfe6eebe621520ee54b418bb/src/lib.rs#L33
// Copyright (c) 2014 The Rust Project Developers
// Permission is hereby granted, free of charge, to any
// person obtaining a copy of this software and associated
// documentation files (the "Software"), to deal in the
// Software without restriction, including without
// limitation the rights to use, copy, modify, merge,
// publish, distribute, sublicense, and/or sell copies of
// the Software, and to permit persons to whom the Software
// is furnished to do so, subject to the following
// conditions:
// The above copyright notice and this permission notice
// shall be included in all copies or substantial portions
// of the Software.
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
// ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
// TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
// PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
// SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
// CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
// IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
// Copyright 2014 The Rust Project Developers
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
use std::ops::{Deref, DerefMut};
use crate::manage_connection::ManageConnection;
use crate::queue::Live;
use crate::Pool;
// From c3po, https://github.com/withoutboats/c3po/blob/08a6fde00c6506bacfe6eebe621520ee54b418bb/src/lib.rs#L40
/// A smart wrapper around a connection which stores it back in the pool
/// when it is dropped.
///
/// This can be dereferences to the `Service` instance this pool manages, and
/// also implements `Service` itself by delegating.
pub struct Conn<C>
where
C: ManageConnection,
C::Connection: Send,
{
/// Actual connection. This should never become a None variant under normal operation.
/// This is an option so we can take the connection on drop, and push it back into the pool
pub conn: Option<Live<C::Connection>>,
/// Underlying pool. A reference is stored here so we can push the connection
/// back into the pool on drop. This should never become a None variant under
/// normal operation. This is an option so we can take the connection on
/// drop, and push it back into the pool
pub pool: Option<Pool<C>>,
/// If true, this connection will be returned to the pool when it is dropped.
/// Otherwise, it will be forgotten.
should_be_put_back: bool,
}
impl<C> Conn<C>
where
C: ManageConnection,
C::Connection: Send,
{
pub(crate) fn new(connection: Live<C::Connection>, pool: Pool<C>) -> Self {
Self {
conn: Some(connection),
pool: Some(pool),
should_be_put_back: true,
}
}
pub(crate) fn forget(mut self) {
self.should_be_put_back = false;
drop(self);
}
}
impl<C> Deref for Conn<C>
where
C: ManageConnection,
C::Connection: Send,
{
type Target = C::Connection;
fn deref(&self) -> &Self::Target {
&self.conn.as_ref().unwrap().conn
}
}
impl<C> DerefMut for Conn<C>
where
C: ManageConnection,
C::Connection: Send,
{
fn deref_mut(&mut self) -> &mut Self::Target {
&mut self.conn.as_mut().unwrap().conn
}
}
impl<C> Drop for Conn<C>
where
C: ManageConnection,
C::Connection: Send,
{
fn drop(&mut self) {
if !self.should_be_put_back {
return;
}
let conn = self.conn.take().unwrap();
let pool = self.pool.take().unwrap();
pool.put_back(conn);
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::tests::DummyManager;
use crate::Config;
use std::time::Duration;
use tokio::time::sleep;
#[tokio::test]
async fn conn_pushes_back_into_pool_after_drop() {
let mngr = DummyManager::new();
let config = Config::new().min_size(2).max_size(2);
let pool = Pool::new(mngr, config).await.unwrap();
assert_eq!(pool.idle_conns(), 2);
let conn = pool.connection().await.unwrap();
assert_eq!(pool.idle_conns(), 1);
::std::mem::drop(conn);
// The connection is added back to the pool asynchronously, so we need
// to wait for the future to finish.
sleep(Duration::from_secs(1)).await;
assert_eq!(pool.idle_conns(), 2);
}
}