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202 lines (171 loc) 路 5.31 KB
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use super::inner::{DecrementSizeGuard, SharedPool};
use crate::connection::Connection;
use crate::database::Database;
use crate::error::Error;
use sqlx_rt::spawn;
use std::fmt::{self, Debug, Formatter};
use std::ops::{Deref, DerefMut};
use std::sync::Arc;
use std::time::Instant;
/// A connection managed by a [`Pool`][crate::pool::Pool].
///
/// Will be returned to the pool on-drop.
pub struct PoolConnection<DB: Database> {
live: Option<Live<DB>>,
pub(crate) pool: Arc<SharedPool<DB>>,
}
pub(super) struct Live<DB: Database> {
pub(super) raw: DB::Connection,
pub(super) created: Instant,
}
pub(super) struct Idle<DB: Database> {
pub(super) live: Live<DB>,
pub(super) since: Instant,
}
/// RAII wrapper for connections being handled by functions that may drop them
pub(super) struct Floating<'p, C> {
inner: C,
guard: DecrementSizeGuard<'p>,
}
const DEREF_ERR: &str = "(bug) connection already released to pool";
impl<DB: Database> Debug for PoolConnection<DB> {
fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
// TODO: Show the type name of the connection ?
f.debug_struct("PoolConnection").finish()
}
}
impl<DB: Database> Deref for PoolConnection<DB> {
type Target = DB::Connection;
fn deref(&self) -> &Self::Target {
&self.live.as_ref().expect(DEREF_ERR).raw
}
}
impl<DB: Database> DerefMut for PoolConnection<DB> {
fn deref_mut(&mut self) -> &mut Self::Target {
&mut self.live.as_mut().expect(DEREF_ERR).raw
}
}
impl<DB: Database> PoolConnection<DB> {
// explicitly release a connection from the pool
pub fn release(mut self) -> DB::Connection {
self.live.take().expect("PoolConnection double-dropped").raw
}
}
/// Returns the connection to the [`Pool`][crate::pool::Pool] it was checked-out from.
impl<DB: Database> Drop for PoolConnection<DB> {
fn drop(&mut self) {
if let Some(mut live) = self.live.take() {
let pool = self.pool.clone();
if live.raw.should_flush() {
spawn(async move {
// flush the connection (will immediately return if not needed) before
// we fully release to the pool
if let Err(e) = live.raw.flush().await {
log::error!("error occurred while flushing the connection: {}", e);
// we now consider the connection to be broken
// close the connection and drop from the pool
let _ = live.float(&pool).into_idle().close().await;
} else {
// after we have flushed successfully, release to the pool
pool.release(live.float(&pool));
}
});
} else {
// nothing to flush, release immediately outside of a spawn
pool.release(live.float(&pool));
}
}
}
}
impl<DB: Database> Live<DB> {
pub fn float(self, pool: &SharedPool<DB>) -> Floating<'_, Self> {
Floating {
inner: self,
guard: DecrementSizeGuard::new(pool),
}
}
pub fn into_idle(self) -> Idle<DB> {
Idle {
live: self,
since: Instant::now(),
}
}
}
impl<DB: Database> Deref for Idle<DB> {
type Target = Live<DB>;
fn deref(&self) -> &Self::Target {
&self.live
}
}
impl<DB: Database> DerefMut for Idle<DB> {
fn deref_mut(&mut self) -> &mut Self::Target {
&mut self.live
}
}
impl<'s, C> Floating<'s, C> {
pub fn into_leakable(self) -> C {
self.guard.cancel();
self.inner
}
}
impl<'s, DB: Database> Floating<'s, Live<DB>> {
pub fn new_live(conn: DB::Connection, guard: DecrementSizeGuard<'s>) -> Self {
Self {
inner: Live {
raw: conn,
created: Instant::now(),
},
guard,
}
}
pub fn attach(self, pool: &Arc<SharedPool<DB>>) -> PoolConnection<DB> {
let Floating { inner, guard } = self;
debug_assert!(
guard.same_pool(pool),
"BUG: attaching connection to different pool"
);
guard.cancel();
PoolConnection {
live: Some(inner),
pool: Arc::clone(pool),
}
}
pub fn into_idle(self) -> Floating<'s, Idle<DB>> {
Floating {
inner: self.inner.into_idle(),
guard: self.guard,
}
}
}
impl<'s, DB: Database> Floating<'s, Idle<DB>> {
pub fn from_idle(idle: Idle<DB>, pool: &'s SharedPool<DB>) -> Self {
Self {
inner: idle,
guard: DecrementSizeGuard::new(pool),
}
}
pub async fn ping(&mut self) -> Result<(), Error> {
self.live.raw.ping().await
}
pub fn into_live(self) -> Floating<'s, Live<DB>> {
Floating {
inner: self.inner.live,
guard: self.guard,
}
}
pub async fn close(self) -> Result<(), Error> {
// `guard` is dropped as intended
self.inner.live.raw.close().await
}
}
impl<C> Deref for Floating<'_, C> {
type Target = C;
fn deref(&self) -> &Self::Target {
&self.inner
}
}
impl<C> DerefMut for Floating<'_, C> {
fn deref_mut(&mut self) -> &mut Self::Target {
&mut self.inner
}
}