From a6e7c3e3d6b91e5aa3c37e2a4b79edf31e445aa2 Mon Sep 17 00:00:00 2001
From: Ivan Tham <pickfire@riseup.net>
Date: Sat, 19 Mar 2022 11:53:43 +0800
Subject: [PATCH] Fix suspend when running hx within git

When editing git commit message using helix, when ctrl-z is pressed
the terminal will get stuck since helix does not suspend correctly,
as helix is currently using tokio with multi-threads, with signal-hook
default low_level::emulate_default_handler it only send the SIGSTOP to
the current process but tokio uses multi-process so not everything gets
suspended and the terminal also gets stuck.

Now switched to use libc kill function and send it to pid 0 so that all
processes gets suspended correctly.
---
 Cargo.lock                    | 23 +++++++++++++++++++++++
 helix-term/Cargo.toml         |  1 +
 helix-term/src/application.rs | 17 ++++++++++++-----
 3 files changed, 36 insertions(+), 5 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index aa17698cc79b..95e158c7fc04 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -451,6 +451,7 @@ dependencies = [
  "helix-view",
  "ignore",
  "log",
+ "nix",
  "num_cpus",
  "once_cell",
  "pulldown-cmark",
@@ -634,6 +635,15 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "memoffset"
+version = "0.6.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5aa361d4faea93603064a027415f07bd8e1d5c88c9fbf68bf56a285428fd79ce"
+dependencies = [
+ "autocfg",
+]
+
 [[package]]
 name = "mio"
 version = "0.7.14"
@@ -670,6 +680,19 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "nix"
+version = "0.23.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9f866317acbd3a240710c63f065ffb1e4fd466259045ccb504130b7f668f35c6"
+dependencies = [
+ "bitflags",
+ "cc",
+ "cfg-if",
+ "libc",
+ "memoffset",
+]
+
 [[package]]
 name = "ntapi"
 version = "0.3.7"
diff --git a/helix-term/Cargo.toml b/helix-term/Cargo.toml
index 4f869b62aced..b579f0dcaf9b 100644
--- a/helix-term/Cargo.toml
+++ b/helix-term/Cargo.toml
@@ -67,6 +67,7 @@ grep-searcher = "0.1.8"
 
 # Remove once retain_mut lands in stable rust
 retain_mut = "0.1.7"
+nix = "0.23"
 
 [target.'cfg(not(windows))'.dependencies]  # https://github.com/vorner/signal-hook/issues/100
 signal-hook-tokio = { version = "0.3", features = ["futures-v0_3"] }
diff --git a/helix-term/src/application.rs b/helix-term/src/application.rs
index 269ce13d15a8..007f88c7723a 100644
--- a/helix-term/src/application.rs
+++ b/helix-term/src/application.rs
@@ -31,10 +31,7 @@ use crossterm::{
     tty::IsTty,
 };
 #[cfg(not(windows))]
-use {
-    signal_hook::{consts::signal, low_level},
-    signal_hook_tokio::Signals,
-};
+use {signal_hook::consts::signal, signal_hook_tokio::Signals};
 #[cfg(windows)]
 type Signals = futures_util::stream::Empty<()>;
 
@@ -254,9 +251,19 @@ impl Application {
         use helix_view::graphics::Rect;
         match signal {
             signal::SIGTSTP => {
+                use nix::{
+                    sys::signal::{self, Signal},
+                    unistd::Pid,
+                };
                 self.compositor.save_cursor();
                 self.restore_term().unwrap();
-                low_level::emulate_default_handler(signal::SIGTSTP).unwrap();
+                // low_level::emulate_default_handler(signal::SIGSTSP) only
+                // send SIGSTOP to the current process but since we use
+                // multi-process tokio, at times like using helix within
+                // git suspend will not work since only the current process
+                // is suspended, so we had to send SIGSTOP signal to the
+                // whole process to make sure it is suspended correctly.
+                signal::kill(Pid::from_raw(0), Signal::SIGSTOP).unwrap();
             }
             signal::SIGCONT => {
                 self.claim_term().await.unwrap();