From 0a2c5e3ca760494e07dd0059e5dbfea9c9c04d3d Mon Sep 17 00:00:00 2001
From: tqcq <99722391+tqcq@users.noreply.github.com>
Date: Wed, 24 Apr 2024 15:36:09 +0800
Subject: [PATCH] fix crash for static ThreadPool

---
 src/sled/futures/future.cc | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/src/sled/futures/future.cc b/src/sled/futures/future.cc
index 4a639e1..71ae37a 100644
--- a/src/sled/futures/future.cc
+++ b/src/sled/futures/future.cc
@@ -14,23 +14,30 @@ DecrementFuturesUsage()
 
 }// namespace future_detail
 
-static ThreadPool g_default_thread_pool;
-TaskQueueBase *g_default_scheduler = &g_default_thread_pool;
+static std::atomic<TaskQueueBase *> g_default_scheduler{nullptr};
+// static ThreadPool default_thread_pool;
+static std::unique_ptr<Thread> g_default_thread;
 
 void
 SetDefaultScheduler(TaskQueueBase *scheduler) noexcept
 {
-    if (scheduler == nullptr) {
-        g_default_scheduler = &g_default_thread_pool;
-    } else {
-        g_default_scheduler = scheduler;
-    }
+    SLED_ASSERT(scheduler, "scheduler is nullptr");
+    g_default_scheduler.store(scheduler, std::memory_order_release);
 }
 
 TaskQueueBase *
 GetDefaultScheduler() noexcept
 {
-    return g_default_scheduler;
+    static std::once_flag flag;
+    std::call_once(flag, [&] {
+        g_default_thread = sled::Thread::Create();
+        g_default_thread->Start();
+        TaskQueueBase *null_scheduler = nullptr;
+        while (g_default_scheduler.load() == nullptr) {
+            g_default_scheduler.compare_exchange_weak(null_scheduler, g_default_thread.get());
+        }
+    });
+    return g_default_scheduler.load(std::memory_order_acquire);
 }
 
 }// namespace sled