Merge pull request #536 from kxt/525-pty-backpressure

Add back pressure to pty

8 files changed, 45 insertions, 16 deletions

diff --git a/src/tests/integration/close_pane.rs b/src/tests/integration/close_pane.rs
index b5ba7f198..598815145 100644
--- a/src/tests/integration/close_pane.rs
+++ b/src/tests/integration/close_pane.rs
@@ -9,7 +9,7 @@ use crate::CliArgs;
 use crate::tests::utils::commands::{
     CLOSE_PANE_IN_PANE_MODE, ESC, MOVE_FOCUS_IN_PANE_MODE, PANE_MODE, QUIT,
     RESIZE_DOWN_IN_RESIZE_MODE, RESIZE_LEFT_IN_RESIZE_MODE, RESIZE_MODE, RESIZE_UP_IN_RESIZE_MODE,
-    SPLIT_DOWN_IN_PANE_MODE, SPLIT_RIGHT_IN_PANE_MODE,
+    SLEEP, SPLIT_DOWN_IN_PANE_MODE, SPLIT_RIGHT_IN_PANE_MODE,
 };
 use zellij_utils::input::config::Config;
 
@@ -404,6 +404,7 @@ pub fn close_pane_with_multiple_panes_above_it_away_from_screen_edges() {
         &MOVE_FOCUS_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
+        &SLEEP,
         &SPLIT_RIGHT_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
@@ -464,6 +465,7 @@ pub fn close_pane_with_multiple_panes_below_it_away_from_screen_edges() {
         &PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
+        &SLEEP,
         &SPLIT_RIGHT_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
@@ -530,6 +532,7 @@ pub fn close_pane_with_multiple_panes_to_the_left_away_from_screen_edges() {
         &MOVE_FOCUS_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
+        &SLEEP,
         &SPLIT_DOWN_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
@@ -592,6 +595,7 @@ pub fn close_pane_with_multiple_panes_to_the_right_away_from_screen_edges() {
         &PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
+        &SLEEP,
         &SPLIT_DOWN_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
diff --git a/src/tests/integration/compatibility.rs b/src/tests/integration/compatibility.rs
index 3b28a9703..ec983b095 100644
--- a/src/tests/integration/compatibility.rs
+++ b/src/tests/integration/compatibility.rs
@@ -8,7 +8,7 @@ use crate::tests::utils::{get_next_to_last_snapshot, get_output_frame_snapshots}
 use crate::CliArgs;
 use zellij_utils::pane_size::PositionAndSize;
 
-use crate::tests::utils::commands::QUIT;
+use crate::tests::utils::commands::{QUIT, SLEEP};
 use zellij_utils::input::config::Config;
 
 /*
@@ -607,7 +607,7 @@ pub fn top_and_quit() {
     };
     let fixture_name = "top_and_quit";
     let mut fake_input_output = get_fake_os_input(&fake_win_size, fixture_name);
-    fake_input_output.add_terminal_input(&[&QUIT]);
+    fake_input_output.add_terminal_input(&[&SLEEP, &QUIT]);
     start(
         Box::new(fake_input_output.clone()),
         CliArgs::default(),
diff --git a/src/tests/integration/resize_down.rs b/src/tests/integration/resize_down.rs
index 4ef45a069..e5d35c266 100644
--- a/src/tests/integration/resize_down.rs
+++ b/src/tests/integration/resize_down.rs
@@ -438,6 +438,7 @@ pub fn resize_down_with_panes_above_aligned_left_and_right_with_current_pane() {
         &SPLIT_DOWN_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
+        &SLEEP,
         &SPLIT_DOWN_IN_PANE_MODE,
         &RESIZE_MODE,
         &RESIZE_DOWN_IN_RESIZE_MODE,
@@ -491,6 +492,7 @@ pub fn resize_down_with_panes_below_aligned_left_and_right_with_current_pane() {
         &SPLIT_DOWN_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
+        &SLEEP,
         &SPLIT_DOWN_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
@@ -547,10 +549,12 @@ pub fn resize_down_with_panes_above_aligned_left_and_right_with_panes_to_the_lef
         &RESIZE_LEFT_IN_RESIZE_MODE,
         &RESIZE_LEFT_IN_RESIZE_MODE,
         &PANE_MODE,
+        &SLEEP,
         &SPLIT_DOWN_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
+        &SLEEP,
         &SPLIT_DOWN_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
@@ -619,6 +623,7 @@ pub fn resize_down_with_panes_below_aligned_left_and_right_with_to_the_left_and_
         &RESIZE_LEFT_IN_RESIZE_MODE,
         &RESIZE_LEFT_IN_RESIZE_MODE,
         &PANE_MODE,
+        &SLEEP,
         &SPLIT_DOWN_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
diff --git a/src/tests/integration/resize_left.rs b/src/tests/integration/resize_left.rs
index 1b8205019..564d5c605 100644
--- a/src/tests/integration/resize_left.rs
+++ b/src/tests/integration/resize_left.rs
@@ -416,6 +416,7 @@ pub fn resize_left_with_panes_to_the_left_aligned_top_and_bottom_with_current_pa
         &SPLIT_RIGHT_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
+        &SLEEP,
         &SPLIT_RIGHT_IN_PANE_MODE,
         &RESIZE_MODE,
         &RESIZE_LEFT_IN_RESIZE_MODE,
@@ -469,6 +470,7 @@ pub fn resize_left_with_panes_to_the_right_aligned_top_and_bottom_with_current_p
         &SPLIT_RIGHT_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
+        &SLEEP,
         &SPLIT_RIGHT_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
@@ -529,6 +531,7 @@ pub fn resize_left_with_panes_to_the_left_aligned_top_and_bottom_with_panes_abov
         &MOVE_FOCUS_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
+        &SLEEP,
         &SPLIT_RIGHT_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
diff --git a/src/tests/integration/resize_right.rs b/src/tests/integration/resize_right.rs
index 44601f2cd..716ed128c 100644
--- a/src/tests/integration/resize_right.rs
+++ b/src/tests/integration/resize_right.rs
@@ -416,6 +416,7 @@ pub fn resize_right_with_panes_to_the_left_aligned_top_and_bottom_with_current_p
         &SPLIT_RIGHT_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
+        &SLEEP,
         &SPLIT_RIGHT_IN_PANE_MODE,
         &RESIZE_MODE,
         &RESIZE_RIGHT_IN_RESIZE_MODE,
@@ -469,6 +470,7 @@ pub fn resize_right_with_panes_to_the_right_aligned_top_and_bottom_with_current_
         &SPLIT_RIGHT_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
+        &SLEEP,
         &SPLIT_RIGHT_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
@@ -529,6 +531,7 @@ pub fn resize_right_with_panes_to_the_left_aligned_top_and_bottom_with_panes_abo
         &MOVE_FOCUS_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
+        &SLEEP,
         &SPLIT_RIGHT_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
diff --git a/src/tests/integration/resize_up.rs b/src/tests/integration/resize_up.rs
index 9aca8d5a2..0097756a8 100644
--- a/src/tests/integration/resize_up.rs
+++ b/src/tests/integration/resize_up.rs
@@ -432,6 +432,7 @@ pub fn resize_up_with_panes_above_aligned_left_and_right_with_current_pane() {
         &SPLIT_DOWN_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
+        &SLEEP,
         &SPLIT_DOWN_IN_PANE_MODE,
         &RESIZE_MODE,
         &RESIZE_UP_IN_RESIZE_MODE,
@@ -485,6 +486,7 @@ pub fn resize_up_with_panes_below_aligned_left_and_right_with_current_pane() {
         &SPLIT_DOWN_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
+        &SLEEP,
         &SPLIT_DOWN_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
@@ -541,10 +543,12 @@ pub fn resize_up_with_panes_above_aligned_left_and_right_with_panes_to_the_left_
         &RESIZE_LEFT_IN_RESIZE_MODE,
         &RESIZE_LEFT_IN_RESIZE_MODE,
         &PANE_MODE,
+        &SLEEP,
         &SPLIT_DOWN_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
+        &SLEEP,
         &SPLIT_DOWN_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
@@ -613,6 +617,7 @@ pub fn resize_up_with_panes_below_aligned_left_and_right_with_to_the_left_and_ri
         &RESIZE_LEFT_IN_RESIZE_MODE,
         &RESIZE_LEFT_IN_RESIZE_MODE,
         &PANE_MODE,
+        &SLEEP,
         &SPLIT_DOWN_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
         &MOVE_FOCUS_IN_PANE_MODE,
diff --git a/zellij-server/src/lib.rs b/zellij-server/src/lib.rs
index 6d33eddf1..2f0389ef7 100644
--- a/zellij-server/src/lib.rs
+++ b/zellij-server/src/lib.rs
@@ -303,6 +303,11 @@ fn init_session(
 ) -> SessionMetaData {
     let (to_screen, screen_receiver): ChannelWithContext<ScreenInstruction> = channels::unbounded();
     let to_screen = SenderWithContext::new(to_screen);
+
+    let (to_screen_bounded, bounded_screen_receiver): ChannelWithContext<ScreenInstruction> =
+        channels::bounded(50);
+    let to_screen_bounded = SenderWithContext::new(to_screen_bounded);
+
     let (to_plugin, plugin_receiver): ChannelWithContext<PluginInstruction> = channels::unbounded();
     let to_plugin = SenderWithContext::new(to_plugin);
     let (to_pty, pty_receiver): ChannelWithContext<PtyInstruction> = channels::unbounded();
@@ -334,7 +339,7 @@ fn init_session(
             let pty = Pty::new(
                 Bus::new(
                     vec![pty_receiver],
-                    Some(&to_screen),
+                    Some(&to_screen_bounded),
                     None,
                     Some(&to_plugin),
                     Some(&to_server),
@@ -351,7 +356,7 @@ fn init_session(
         .name("screen".to_string())
         .spawn({
             let screen_bus = Bus::new(
-                vec![screen_receiver],
+                vec![screen_receiver, bounded_screen_receiver],
                 None,
                 Some(&to_pty),
                 Some(&to_plugin),
diff --git a/zellij-server/src/pty.rs b/zellij-server/src/pty.rs
index 803c04248..41f9d1a9b 100644
--- a/zellij-server/src/pty.rs
+++ b/zellij-server/src/pty.rs
@@ -148,6 +148,12 @@ async fn deadline_read(
     }
 }
 
+async fn async_send_to_screen(senders: ThreadSenders, screen_instruction: ScreenInstruction) {
+    task::spawn_blocking(move || senders.send_to_screen(screen_instruction))
+        .await
+        .unwrap()
+}
+
 fn stream_terminal_bytes(
     pid: RawFd,
     senders: ThreadSenders,
@@ -171,36 +177,34 @@ fn stream_terminal_bytes(
                 match deadline_read(async_reader.as_mut(), render_deadline, &mut buf).await {
                     ReadResult::Ok(0) | ReadResult::Err(_) => break, // EOF or error
                     ReadResult::Timeout => {
-                        let _ = senders.send_to_screen(ScreenInstruction::Render);
+                        async_send_to_screen(senders.clone(), ScreenInstruction::Render).await;
                         // next read does not need a deadline as we just rendered everything
                         render_deadline = None;
-
-                        // yield so Screen thread has some time to render before send additional
-                        // PtyBytes.
-                        task::sleep(Duration::from_millis(10)).await;
                     }
                     ReadResult::Ok(n_bytes) => {
                         let bytes = &buf[..n_bytes];
                         if debug {
                             let _ = debug_to_file(bytes, pid);
                         }
-                        let _ = senders
-                            .send_to_screen(ScreenInstruction::PtyBytes(pid, bytes.to_vec()));
+                        async_send_to_screen(
+                            senders.clone(),
+                            ScreenInstruction::PtyBytes(pid, bytes.to_vec()),
+                        )
+                        .await;
                         // if we already have a render_deadline we keep it, otherwise we set it
                         // to the duration of `render_pause`.
                         render_deadline.get_or_insert(Instant::now() + render_pause);
                     }
                 }
             }
-            let _ = senders.send_to_screen(ScreenInstruction::Render);
+            async_send_to_screen(senders.clone(), ScreenInstruction::Render).await;
 
             #[cfg(not(any(feature = "test", test)))]
             // this is a little hacky, and is because the tests end the file as soon as
             // we read everything, rather than hanging until there is new data
             // a better solution would be to fix the test fakes, but this will do for now
-            senders
-                .send_to_screen(ScreenInstruction::ClosePane(PaneId::Terminal(pid)))
-                .unwrap();
+            async_send_to_screen(senders, ScreenInstruction::ClosePane(PaneId::Terminal(pid)))
+                .await;
         }
     })
 }