From 620bec9cae0507ff3e0e1f460b1f4b70e35bc9b1 Mon Sep 17 00:00:00 2001
From: Thad House <ThadHouse@users.noreply.github.com>
Date: Sun, 5 May 2019 17:38:56 -0700
Subject: [PATCH] wpiutil: uv: Add LoopClosing status to Handle (#1647)

Useful for EventLoopRunner to know if a stop is requested, or close is happening for another reason.
---
 .../src/main/native/cpp/EventLoopRunner.cpp   |  5 +++-
 .../src/main/native/include/wpi/uv/Handle.h   | 24 +++++++++++++++++++
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/wpiutil/src/main/native/cpp/EventLoopRunner.cpp b/wpiutil/src/main/native/cpp/EventLoopRunner.cpp
index b885385279..2ae6b47ac6 100644
--- a/wpiutil/src/main/native/cpp/EventLoopRunner.cpp
+++ b/wpiutil/src/main/native/cpp/EventLoopRunner.cpp
@@ -49,7 +49,10 @@ EventLoopRunner::~EventLoopRunner() { Stop(); }
 void EventLoopRunner::Stop() {
   ExecAsync([](uv::Loop& loop) {
     // close all handles; this will (eventually) stop the loop
-    loop.Walk([](uv::Handle& h) { h.Close(); });
+    loop.Walk([](uv::Handle& h) {
+      h.SetLoopClosing(true);
+      h.Close();
+    });
   });
   m_owner.Join();
 }
diff --git a/wpiutil/src/main/native/include/wpi/uv/Handle.h b/wpiutil/src/main/native/include/wpi/uv/Handle.h
index 046c1551d0..dac1c4afc9 100644
--- a/wpiutil/src/main/native/include/wpi/uv/Handle.h
+++ b/wpiutil/src/main/native/include/wpi/uv/Handle.h
@@ -119,6 +119,29 @@ class Handle : public std::enable_shared_from_this<Handle> {
    */
   void Close() noexcept;
 
+  /**
+   * Set if the loop is closing.
+   *
+   * This is set during EventLoopRunner.Stop(), and can be used for other cases
+   * to indicate the loop should be closing. For instance for a uv_walk loop can
+   * use this to close existing handles.
+   *
+   * @param loopClosing true to set the loop currently in closing stages.
+   */
+  void SetLoopClosing(bool loopClosing) noexcept {
+    m_loopClosing = loopClosing;
+  }
+
+  /**
+   * Get the loop closing status.
+   *
+   * This can be used from closed() in order to tell if a closing loop is the
+   * reason for the close, or another reason.
+   *
+   * @return true if the loop is closing, otherwise false.
+   */
+  bool IsLoopClosing() const noexcept { return m_loopClosing; }
+
   /**
    * Reference the given handle.
    *
@@ -237,6 +260,7 @@ class Handle : public std::enable_shared_from_this<Handle> {
   std::shared_ptr<Handle> m_self;
   uv_handle_t* m_uv_handle;
   bool m_closed = false;
+  bool m_loopClosing = false;
   std::function<Buffer(size_t)> m_allocBuf{&Buffer::Allocate};
   std::function<void(Buffer&)> m_freeBuf{&DefaultFreeBuf};
   std::shared_ptr<void> m_data;