From 50c35fc057be67eca70c42e3892aca8b9984b86b Mon Sep 17 00:00:00 2001
From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Fri, 2 Apr 2021 15:58:30 +0100
Subject: [PATCH] apitest: Move OtterPaused from wdt-simple

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---
 apitest/apitest.rs    | 30 +++++++++++++++++++++++++++++-
 wdriver/wdt-simple.rs |  5 ++---
 2 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/apitest/apitest.rs b/apitest/apitest.rs
index 3c03dd43..58305f72 100644
--- a/apitest/apitest.rs
+++ b/apitest/apitest.rs
@@ -68,7 +68,7 @@ pub struct Opts {
 pub struct SetupCore {
   pub ds: DirSubst,
   pub mgmt_conn: MgmtChannel,
-  pub server_child: Child,
+  server_child: Child,
   pub wanted_tests: TrackWantedTests,
 }
 
@@ -763,6 +763,34 @@ impl DirSubst {
   }
 }
 
+// -------------------- concurrency management --------------------
+
+pub struct OtterPaused(nix::unistd::Pid);
+
+impl SetupCore {
+  #[throws(AE)]
+  pub fn pause_otter(&self) -> OtterPaused {
+    let pid = nix::unistd::Pid::from_raw(
+      self.server_child.id() as nix::libc::pid_t
+    );
+    nix::sys::signal::kill(pid, nix::sys::signal::SIGSTOP)?;
+    OtterPaused(pid)
+  }
+}
+
+impl OtterPaused {
+  #[throws(AE)]
+  pub fn resume(self) {
+    nix::sys::signal::kill(self.0, nix::sys::signal::SIGCONT)?;
+  }
+}
+
+impl Drop for OtterPaused {
+  fn drop(&mut self) {
+    debug!("note, otter server pid={} was still paused", self.0);
+  }
+}
+
 // -------------------- utilities --------------------
 
 #[ext(pub)]
diff --git a/wdriver/wdt-simple.rs b/wdriver/wdt-simple.rs
index 4fc17769..35e37c5a 100644
--- a/wdriver/wdt-simple.rs
+++ b/wdriver/wdt-simple.rs
@@ -204,8 +204,7 @@ impl Ctx {
 
     dbg!(&sides);
 
-    let pid = nix::unistd::Pid::from_raw(su.server_child.id() as nix::libc::pid_t);
-    nix::sys::signal::kill(pid, nix::sys::signal::SIGSTOP)?;
+    let paused = su.pause_otter()?;
 
     for side in &sides {
       let w = su.w(side.window)?;
@@ -223,7 +222,7 @@ impl Ctx {
         .context("conflicting drag")?;
     }
 
-    nix::sys::signal::kill(pid, nix::sys::signal::SIGCONT)?;
+    paused.resume()?;
 
     #[derive(Debug)]
     struct Got<'s> {
-- 
2.30.2