emscripten_push_main_loop_blocker

src/library_browser.js

@@ -12,6 +12,7 @@ mergeInto(LibraryManager.library, {
       scheduler: null,
       shouldPause: false,
       paused: false,
+      queue: [],
       pause: function() {
         Browser.mainLoop.shouldPause = true;
       },
@@ -220,6 +221,11 @@ mergeInto(LibraryManager.library, {
 
     var jsFunc = FUNCTION_TABLE[func];
     var wrapper = function() {
+      if (Browser.mainLoop.queue.length > 0) {
+        Browser.mainLoop.queue.shift()();
+        Browser.mainLoop.scheduler();
+        return;
+      }
       if (Browser.mainLoop.shouldPause) {
         // catch pauses from non-main loop sources
         Browser.mainLoop.paused = true;
@@ -247,19 +253,23 @@ mergeInto(LibraryManager.library, {
     Browser.mainLoop.scheduler();
   },
 
-  emscripten_cancel_main_loop: function(func) {
+  emscripten_cancel_main_loop: function() {
     Browser.mainLoop.scheduler = null;
     Browser.mainLoop.shouldPause = true;
   },
 
-  emscripten_pause_main_loop: function(func) {
+  emscripten_pause_main_loop: function() {
     Browser.mainLoop.pause();
   },
 
-  emscripten_resume_main_loop: function(func) {
+  emscripten_resume_main_loop: function() {
     Browser.mainLoop.resume();
   },
 
+  emscripten_push_main_loop_blocker: function(func) {
+    Browser.mainLoop.queue.push(FUNCTION_TABLE[func]);
+  },
+
   emscripten_async_call: function(func, millis) {
     Module['noExitRuntime'] = true;
 

system/include/emscripten/emscripten.h

@@ -48,6 +48,12 @@ extern void emscripten_pause_main_loop();
 extern void emscripten_resume_main_loop();
 extern void emscripten_cancel_main_loop();
 
+/*
+ * Add a function to a queue of events that will execute
+ * before the main loop will continue.
+ */
+extern void emscripten_push_main_loop_blocker(void (*func)());
+
 /*
  * Call a C function asynchronously, that is, after returning
  * control to the JS event loop. This is done by a setTimeout.

tests/emscripten_api_browser.cpp

@@ -9,6 +9,19 @@ int last = 0;
 
 extern "C" {
 
+bool pre1ed = false;
+bool pre2ed = false;
+void pre1() {
+  assert(!pre1ed);
+  assert(!pre2ed);
+  pre1ed = true;
+}
+void pre2() {
+  assert(pre1ed);
+  assert(!pre2ed);
+  pre2ed = true;
+}
+
 bool fived = false;
 void five() {
   fived = true;
@@ -22,7 +35,14 @@ void mainey() {
     emscripten_pause_main_loop();
     emscripten_async_call(five, 1000);
   } else if (counter == 22) { // very soon after 20, so without pausing we fail
-    int result = fived;
+    assert(fived);
+    emscripten_push_main_loop_blocker(pre1);
+    emscripten_push_main_loop_blocker(pre2);
+  } else if (counter == 23) {
+    assert(pre1ed);
+    assert(pre2ed);
+    printf("Good!\n");
+    int result = 1;
     REPORT_RESULT();
   }
 }