[pbs-devel] [PATCH proxmox 2/3] RateLimitedStream: implement poll_write_vectored

[Dietmar Maurer <dietmar@proxmox.com>]

Signed-off-by: Dietmar Maurer <dietmar@proxmox.com>
---
 .../src/client/rate_limited_stream.rs         | 92 +++++++++++++------
 1 file changed, 62 insertions(+), 30 deletions(-)

diff --git a/proxmox-http/src/client/rate_limited_stream.rs b/proxmox-http/src/client/rate_limited_stream.rs
index 434f923..8b4123f 100644
--- a/proxmox-http/src/client/rate_limited_stream.rs
+++ b/proxmox-http/src/client/rate_limited_stream.rs
@@ -2,6 +2,7 @@ use std::pin::Pin;
 use std::marker::Unpin;
 use std::sync::{Arc, Mutex};
 use std::time::{Duration, Instant};
+use std::io::IoSlice;
 
 use futures::Future;
 use tokio::io::{ReadBuf, AsyncRead, AsyncWrite};
@@ -22,8 +23,6 @@ pub struct RateLimitedStream<S> {
 
 impl <S> RateLimitedStream<S> {
 
-    const MIN_DELAY: Duration = Duration::from_millis(20);
-
     /// Creates a new instance with reads and writes limited to the same `rate`.
     pub fn new(stream: S, rate: u64) -> Self {
         let now = Instant::now();
@@ -48,6 +47,33 @@ impl <S> RateLimitedStream<S> {
     }
 }
 
+fn register_traffic(
+    limiter: &Mutex<RateLimiter>,
+    count: usize,
+) -> Option<Pin<Box<Sleep>>>{
+
+    const MIN_DELAY: Duration = Duration::from_millis(10);
+
+    let now = Instant::now();
+    let delay = limiter.lock().unwrap()
+        .register_traffic(now, count as u64);
+    if delay >= MIN_DELAY {
+        let sleep = tokio::time::sleep(delay);
+        Some(Box::pin(sleep))
+    } else {
+        None
+    }
+}
+
+fn delay_is_ready(delay: &mut Option<Pin<Box<Sleep>>>, ctx: &mut Context<'_>) -> bool {
+    match delay {
+        Some(ref mut future) => {
+            future.as_mut().poll(ctx).is_ready()
+        }
+        None => true,
+    }
+}
+
 impl <S: AsyncWrite + Unpin> AsyncWrite for RateLimitedStream<S> {
 
     fn poll_write(
@@ -57,12 +83,7 @@ impl <S: AsyncWrite + Unpin> AsyncWrite for RateLimitedStream<S> {
     ) -> Poll<Result<usize, std::io::Error>> {
         let this = self.get_mut();
 
-        let is_ready = match this.write_delay {
-            Some(ref mut future) => {
-                future.as_mut().poll(ctx).is_ready()
-            }
-            None => true,
-        };
+        let is_ready = delay_is_ready(&mut this.write_delay, ctx);
 
         if !is_ready { return Poll::Pending; }
 
@@ -70,15 +91,37 @@ impl <S: AsyncWrite + Unpin> AsyncWrite for RateLimitedStream<S> {
 
         let result = Pin::new(&mut this.stream).poll_write(ctx, buf);
 
-        if let Some(ref write_limiter) = this.write_limiter {
-            if let Poll::Ready(Ok(count)) = &result {
-                let now = Instant::now();
-                let delay = write_limiter.lock().unwrap()
-                    .register_traffic(now, *count as u64);
-                if delay >= Self::MIN_DELAY {
-                    let sleep = tokio::time::sleep(delay);
-                    this.write_delay = Some(Box::pin(sleep));
-                }
+        if let Some(ref limiter) = this.write_limiter {
+            if let Poll::Ready(Ok(count)) = result {
+                this.write_delay = register_traffic(limiter, count);
+            }
+        }
+
+        result
+    }
+
+    fn is_write_vectored(&self) -> bool {
+        self.stream.is_write_vectored()
+    }
+
+    fn poll_write_vectored(
+        self: Pin<&mut Self>,
+        ctx: &mut Context<'_>,
+        bufs: &[IoSlice<'_>]
+    ) -> Poll<Result<usize, std::io::Error>> {
+        let this = self.get_mut();
+
+        let is_ready = delay_is_ready(&mut this.write_delay, ctx);
+
+        if !is_ready { return Poll::Pending; }
+
+        this.write_delay = None;
+
+        let result = Pin::new(&mut this.stream).poll_write_vectored(ctx, bufs);
+
+        if let Some(ref limiter) = this.write_limiter {
+            if let Poll::Ready(Ok(count)) = result {
+                this.write_delay = register_traffic(limiter, count);
             }
         }
 
@@ -111,12 +154,7 @@ impl <S: AsyncRead + Unpin> AsyncRead for RateLimitedStream<S> {
     ) -> Poll<Result<(), std::io::Error>> {
         let this = self.get_mut();
 
-        let is_ready = match this.read_delay {
-            Some(ref mut future) => {
-                future.as_mut().poll(ctx).is_ready()
-            }
-            None => true,
-        };
+        let is_ready = delay_is_ready(&mut this.read_delay, ctx);
 
         if !is_ready { return Poll::Pending; }
 
@@ -128,13 +166,7 @@ impl <S: AsyncRead + Unpin> AsyncRead for RateLimitedStream<S> {
         if let Some(ref read_limiter) = this.read_limiter {
             if let Poll::Ready(Ok(())) = &result {
                 let count = buf.filled().len() - filled_len;
-                let now = Instant::now();
-                let delay = read_limiter.lock().unwrap()
-                    .register_traffic(now, count as u64);
-                if delay >= Self::MIN_DELAY {
-                    let sleep = tokio::time::sleep(delay);
-                    this.read_delay = Some(Box::pin(sleep));
-                }
+                this.read_delay = register_traffic(read_limiter, count);
             }
         }
 
-- 
2.30.2