From 19dcd363d13e6d067b92b79da8f3ed2a361f438d Mon Sep 17 00:00:00 2001
From: ReinUsesLisp <reinuseslisp@airmail.cc>
Date: Thu, 21 Jan 2021 00:06:39 -0300
Subject: [PATCH] threadsafe_queue: Add std::stop_token overload to PopWait

---
 src/common/threadsafe_queue.h | 31 ++++++++++++++++++++++++-------
 1 file changed, 24 insertions(+), 7 deletions(-)

diff --git a/src/common/threadsafe_queue.h b/src/common/threadsafe_queue.h
index ad04df8cab..53298421c4 100644
--- a/src/common/threadsafe_queue.h
+++ b/src/common/threadsafe_queue.h
@@ -14,7 +14,7 @@
 #include <utility>
 
 namespace Common {
-template <typename T>
+template <typename T, bool with_stop_token = false>
 class SPSCQueue {
 public:
     SPSCQueue() {
@@ -70,9 +70,9 @@ public:
     }
 
     bool Pop(T& t) {
-        if (Empty())
+        if (Empty()) {
             return false;
-
+        }
         --size;
 
         ElementPtr* tmpptr = read_ptr;
@@ -86,7 +86,7 @@ public:
     void Wait() {
         if (Empty()) {
             std::unique_lock lock{cv_mutex};
-            cv.wait(lock, [this]() { return !Empty(); });
+            cv.wait(lock, [this] { return !Empty(); });
         }
     }
 
@@ -97,6 +97,19 @@ public:
         return t;
     }
 
+    T PopWait(std::stop_token stop_token) {
+        if (Empty()) {
+            std::unique_lock lock{cv_mutex};
+            cv.wait(lock, stop_token, [this] { return !Empty(); });
+        }
+        if (stop_token.stop_requested()) {
+            return T{};
+        }
+        T t;
+        Pop(t);
+        return t;
+    }
+
     // not thread-safe
     void Clear() {
         size.store(0);
@@ -125,13 +138,13 @@ private:
     ElementPtr* read_ptr;
     std::atomic_size_t size{0};
     std::mutex cv_mutex;
-    std::condition_variable cv;
+    std::conditional_t<with_stop_token, std::condition_variable_any, std::condition_variable> cv;
 };
 
 // a simple thread-safe,
 // single reader, multiple writer queue
 
-template <typename T>
+template <typename T, bool with_stop_token = false>
 class MPSCQueue {
 public:
     [[nodiscard]] std::size_t Size() const {
@@ -168,13 +181,17 @@ public:
         return spsc_queue.PopWait();
     }
 
+    T PopWait(std::stop_token stop_token) {
+        return spsc_queue.PopWait(stop_token);
+    }
+
     // not thread-safe
     void Clear() {
         spsc_queue.Clear();
     }
 
 private:
-    SPSCQueue<T> spsc_queue;
+    SPSCQueue<T, with_stop_token> spsc_queue;
     std::mutex write_lock;
 };
 } // namespace Common