[fix] Startup failure on Windows due to unexpected global object cons…

…truction order in Data::Producer

src/data.cpp

@@ -30,13 +30,17 @@
 namespace pipy {
 
 List<Data::Producer> Data::Producer::s_all_producers;
-std::mutex Data::Producer::s_all_producers_mutex;
 Data::Producer Data::s_unknown_producer("Unknown");
 
 auto Data::Producer::unknown() -> Producer* {
   return &s_unknown_producer;
 }
 
+auto Data::Producer::producer_list_mutex() -> std::mutex& {
+  static std::mutex s_mutex;
+  return s_mutex;
+}
+
 void Data::pack(const Data &data, Producer *producer, double vacancy) {
   assert_same_thread(*this);
   if (&data == this) return;

src/data.hpp

@@ -75,14 +75,14 @@ class Data : public EventTemplate<Data> {
     static auto unknown() -> Producer*;
 
     static void for_each(const std::function<void(Producer*)> &cb) {
-      std::lock_guard<std::mutex> lock(s_all_producers_mutex);
+      std::lock_guard<std::mutex> lock(producer_list_mutex());
       for (auto p = s_all_producers.head(); p; p = p->next()) {
         cb(p);
       }
     }
 
     Producer(const std::string &name) : m_name(name), m_count(0) {
-      std::lock_guard<std::mutex> lock(s_all_producers_mutex);
+      std::lock_guard<std::mutex> lock(producer_list_mutex());
       s_all_producers.push(this);
     }
 
@@ -109,11 +109,12 @@ class Data : public EventTemplate<Data> {
     std::string m_name;
     std::atomic<size_t> m_count;
 
+    static auto producer_list_mutex() -> std::mutex&;
+
     void increase() { m_count.fetch_add(1, std::memory_order_relaxed); }
     void decrease() { m_count.fetch_sub(1, std::memory_order_relaxed); }
 
     static List<Producer> s_all_producers;
-    static std::mutex s_all_producers_mutex;
 
     friend struct Chunk;
   };