Remodel threading to use a global thread pool so it never block on the main thread. Bump emscripten to 3.1.65

src/Util.cc

@@ -1,5 +1,6 @@
 #include "Util.h"
-
+#include <emscripten/em_asm.h>
+ThreadPool globalPool;
 void fireEv(int index, const char* content, const char* type) {
   MAIN_THREAD_EM_ASM({
     objs[$0].dispatchEvent(new CustomEvent($2 === 0 ? "0" : UTF8ToString($2), { "detail" : UTF8ToString($1) }));
@@ -44,4 +45,42 @@ int untar(unsigned char* tar, int tarSize, const std::string& storepath) {
     }
   }
   return Successful;
+}
+void Thread::startup(ThreadPool* pool) {
+  while(!pool->done) {
+    // Wait until unlocked
+    emscripten_atomic_wait_u32(&pool->qLock, true, -1);
+    if(pool->done) break;
+    // If there is no task then everyone has to wait until there is more
+    if(pool->taskQ.empty()) {
+      emscripten_atomic_store_u32(&pool->qLock, true);
+      continue;
+    }
+    // If this locks, the returned (loaded) value will be false, and we move on
+    if(emscripten_atomic_cas_u32(&pool->qLock, false, true)) continue;
+    fn = pool->taskQ.front();
+    pool->taskQ.pop();
+    // Unlock
+    emscripten_atomic_store_u32(&pool->qLock, false);
+    emscripten_atomic_notify(&pool->qLock, 1);
+    fn();
+  }   
+}
+ThreadPool::ThreadPool() {
+  for(Thread& thrd : threads) {
+    thrd.handle = std::thread{&Thread::startup, &thrd, this};
+  }
+}
+ThreadPool::~ThreadPool() {
+  done = true;
+  emscripten_atomic_store_u32(&qLock, false);
+  emscripten_atomic_notify(&qLock, -1);
+  for(Thread& thrd : threads) {
+    thrd.handle.detach();
+  }
+}
+void ThreadPool::exec(std::function<void()> fn) {
+  taskQ.emplace(fn);
+  emscripten_atomic_store_u32(&qLock, false);
+  emscripten_atomic_notify(&qLock, 1);
 }