From e72ee2823261c4a08dfd4133963ae6161b6f7ff9 Mon Sep 17 00:00:00 2001
From: Andrew <amcharg@gmail.com>
Date: Wed, 17 Jun 2020 00:58:23 -0700
Subject: [PATCH] Enforce HW_BUFFER_SIZE inside h1::dispatcher (#1550)

---
 CHANGES.md                      | 6 ++++++
 actix-http/src/h1/dispatcher.rs | 7 +++++++
 2 files changed, 13 insertions(+)

diff --git a/CHANGES.md b/CHANGES.md
index 739f1b13c..3b4b8dc0b 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,5 +1,11 @@
 # Changes
 
+## [Unreleased]
+
+### Changed
+
+* Fix actix_http::h1::dispatcher so it returns when HW_BUFFER_SIZE is reached. Should reduce peak memory consumption during large uploads. [#1550]
+
 ## [3.0.0-alpha.3] - 2020-05-21
 
 ### Added
diff --git a/actix-http/src/h1/dispatcher.rs b/actix-http/src/h1/dispatcher.rs
index e16d3536f..51f107efb 100644
--- a/actix-http/src/h1/dispatcher.rs
+++ b/actix-http/src/h1/dispatcher.rs
@@ -861,7 +861,14 @@ where
     T: AsyncRead + Unpin,
 {
     let mut read_some = false;
+
     loop {
+        // If buf is full return but do not disconnect since
+        // there is more reading to be done
+        if buf.len() >= HW_BUFFER_SIZE {
+            return Ok(Some(false));
+        }
+
         let remaining = buf.capacity() - buf.len();
         if remaining < LW_BUFFER_SIZE {
             buf.reserve(HW_BUFFER_SIZE - remaining);