From e6fb5f81b3bffa62cd0a6c49f8f933cdc7b301b4 Mon Sep 17 00:00:00 2001
From: Max Inden <mail@max-inden.de>
Date: Thu, 23 Nov 2023 15:31:47 +0100
Subject: [PATCH] Unbounded stream receive window

Depend on connection window only.
---
 test-harness/src/lib.rs        |  6 +++++-
 yamux/src/connection/stream.rs |  4 ++--
 yamux/src/lib.rs               | 12 +++++++-----
 3 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/test-harness/src/lib.rs b/test-harness/src/lib.rs
index 72e2a596..acd43cc9 100644
--- a/test-harness/src/lib.rs
+++ b/test-harness/src/lib.rs
@@ -449,7 +449,11 @@ impl Arbitrary for TestConfig {
     fn arbitrary(g: &mut Gen) -> Self {
         let mut c = Config::default();
         c.set_read_after_close(Arbitrary::arbitrary(g));
-        c.set_receive_window(256 * 1024 + usize::arbitrary(g) % (768 * 1024));
+        if bool::arbitrary(g) {
+            c.set_receive_window(Some(256 * 1024 + usize::arbitrary(g) % (768 * 1024)));
+        } else {
+            c.set_receive_window(None);
+        }
         TestConfig(c)
     }
 }
diff --git a/yamux/src/connection/stream.rs b/yamux/src/connection/stream.rs
index 0ccc638f..08c754ac 100644
--- a/yamux/src/connection/stream.rs
+++ b/yamux/src/connection/stream.rs
@@ -25,7 +25,6 @@ use futures::{
     ready, SinkExt,
 };
 use parking_lot::{Mutex, MutexGuard};
-use std::convert::TryInto;
 use std::time::Instant;
 use std::{
     fmt, io,
@@ -546,6 +545,7 @@ impl Shared {
             self.window_max,
             self.window
         );
+
         let bytes_received = self.window_max.saturating_sub(self.window);
         let buffer_len = self.buffer.len();
         let mut new_credit = bytes_received.saturating_sub(buffer_len);
@@ -571,7 +571,7 @@ impl Shared {
                 self.window_max = std::cmp::min(
                     std::cmp::min(
                         self.window_max.saturating_mul(2),
-                        self.config.receive_window,
+                        self.config.receive_window.unwrap_or(usize::MAX),
                     ),
                     self.window_max
                         + ((self.config.connection_window
diff --git a/yamux/src/lib.rs b/yamux/src/lib.rs
index d3935d77..fbb56a39 100644
--- a/yamux/src/lib.rs
+++ b/yamux/src/lib.rs
@@ -77,7 +77,7 @@ const DEFAULT_SPLIT_SEND_SIZE: usize = 16 * 1024;
 #[derive(Debug, Clone)]
 pub struct Config {
     // TODO: Rename to max_stream_receive_window
-    receive_window: usize,
+    receive_window: Option<usize>,
     // TODO: Rename to max_connection_receive_window
     connection_window: usize,
     max_buffer_size: usize,
@@ -89,7 +89,8 @@ pub struct Config {
 impl Default for Config {
     fn default() -> Self {
         Config {
-            receive_window: 16 * 1024 * 1024,
+            // TODO: Add rational: given that we have a connection window, ...
+            receive_window: None,
             // TODO: reevaluate default.
             // TODO: Add setter.
             connection_window: 1 * 1024 * 1024 * 1024,
@@ -108,12 +109,12 @@ impl Config {
     /// # Panics
     ///
     /// If the given receive window is < 256 KiB.
-    pub fn set_receive_window(&mut self, n: usize) -> &mut Self {
+    pub fn set_receive_window(&mut self, n: Option<usize>) -> &mut Self {
         self.receive_window = n;
         self.check();
         self
     }
-    
+
     pub fn set_connection_window(&mut self, n: usize) -> &mut Self {
         self.connection_window = n;
         self.check();
@@ -150,8 +151,9 @@ impl Config {
         self
     }
 
+    // TODO: Consider doing the check on creation, not on each builder method call.
     fn check(&self) {
-        assert!(self.receive_window >= DEFAULT_CREDIT);
+        assert!(self.receive_window.unwrap_or(usize::MAX) >= DEFAULT_CREDIT);
         assert!(self.connection_window >= self.max_num_streams * DEFAULT_CREDIT);
     }
 }