avm2: Implement flash.system.System.gc()

core/src/avm2/globals/flash/system/System.as

@@ -4,7 +4,7 @@ package flash.system {
         import __ruffle__.stub_method;
         import __ruffle__.stub_getter;
 
-        public static function gc():void {}
+        public static native function gc():void;
 
         public static function pauseForGCIfCollectionImminent(imminence:Number = 0.75):void {
             stub_method("flash.system.System", "pauseForGCIfCollectionImminent");

core/src/avm2/globals/flash/system/system.rs

@@ -5,6 +5,16 @@ use crate::avm2::activation::Activation;
 use crate::avm2::parameters::ParametersExt;
 use crate::avm2::value::Value;
 
+/// Implements `flash.system.System.setClipboard` method
+pub fn gc<'gc>(
+    activation: &mut Activation<'_, 'gc>,
+    _this: Value<'gc>,
+    _args: &[Value<'gc>],
+) -> Result<Value<'gc>, Error<'gc>> {
+    *activation.context.needs_gc = true;
+    Ok(Value::Undefined)
+}
+
 /// Implements `flash.system.System.setClipboard` method
 pub fn set_clipboard<'gc>(
     activation: &mut Activation<'_, 'gc>,

core/src/context.rs

@@ -87,6 +87,9 @@ pub struct UpdateContext<'gc> {
     /// Requests that the player re-renders after this execution (e.g. due to `updateAfterEvent`).
     pub needs_render: &'gc mut bool,
 
+    // Requests that the gc finishes it's cycle this execution (e.g. due to 'flash.system.System.gc()')
+    pub needs_gc: &'gc mut bool,
+
     /// The root SWF file.
     pub root_swf: &'gc mut Arc<SwfMovie>,
 

core/src/player.rs

@@ -307,6 +307,7 @@ pub struct Player {
 
     run_state: RunState,
     needs_render: bool,
+    needs_gc: bool,
 
     renderer: Box<dyn RenderBackend>,
     audio: Box<dyn AudioBackend>,
@@ -2290,6 +2291,7 @@ impl Player {
                 timers,
                 current_context_menu,
                 needs_render: &mut this.needs_render,
+                needs_gc: &mut this.needs_gc,
                 avm1,
                 avm2,
                 external_interface,
@@ -2382,6 +2384,10 @@ impl Player {
 
         // GC
         self.gc_arena.borrow_mut().collect_debt();
+        if self.needs_gc {
+            self.gc_arena.borrow_mut().finish_cycle();
+        }
+        self.needs_gc = false;
 
         rval
     }
@@ -3038,6 +3044,7 @@ impl PlayerBuilder {
                     RunState::Suspended
                 },
                 needs_render: true,
+                needs_gc: false,
                 self_reference: self_ref.clone(),
                 load_behavior: self.load_behavior,
                 spoofed_url: self.spoofed_url.clone(),