avm2: Add `Stage` class stub

core/src/avm2/globals.rs

@@ -109,6 +109,7 @@ pub struct SystemPrototypes<'gc> {
     pub graphics: Object<'gc>,
     pub loaderinfo: Object<'gc>,
     pub bytearray: Object<'gc>,
+    pub stage: Object<'gc>,
 }
 
 impl<'gc> SystemPrototypes<'gc> {
@@ -153,6 +154,7 @@ impl<'gc> SystemPrototypes<'gc> {
             graphics: empty,
             loaderinfo: empty,
             bytearray: empty,
+            stage: empty,
         }
     }
 }
@@ -750,6 +752,19 @@ pub fn load_player_globals<'gc>(
         domain,
         script,
     )?;
+    activation
+        .context
+        .avm2
+        .system_prototypes
+        .as_mut()
+        .unwrap()
+        .stage = class(
+        activation,
+        flash::display::stage::create_class(mc),
+        implicit_deriver,
+        domain,
+        script,
+    )?;
 
     // package `flash.geom`
     activation

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

@@ -14,4 +14,5 @@ pub mod movieclip;
 pub mod scene;
 pub mod shape;
 pub mod sprite;
+pub mod stage;
 pub mod swfversion;

core/src/avm2/globals/flash/display/stage.rs

@@ -0,0 +1,55 @@
+//! `flash.display.Stage` builtin/prototype
+
+use crate::avm2::activation::Activation;
+use crate::avm2::class::{Class, ClassAttributes};
+use crate::avm2::method::Method;
+use crate::avm2::names::{Namespace, QName};
+use crate::avm2::object::Object;
+use crate::avm2::value::Value;
+use crate::avm2::Error;
+use gc_arena::{GcCell, MutationContext};
+
+/// Implements `flash.display.Stage`'s instance constructor.
+pub fn instance_init<'gc>(
+    activation: &mut Activation<'_, 'gc, '_>,
+    this: Option<Object<'gc>>,
+    _args: &[Value<'gc>],
+) -> Result<Value<'gc>, Error> {
+    if let Some(this) = this {
+        activation.super_init(this, &[])?;
+    }
+
+    Ok(Value::Undefined)
+}
+
+/// Implements `flash.display.Stage`'s class constructor.
+pub fn class_init<'gc>(
+    _activation: &mut Activation<'_, 'gc, '_>,
+    _this: Option<Object<'gc>>,
+    _args: &[Value<'gc>],
+) -> Result<Value<'gc>, Error> {
+    Ok(Value::Undefined)
+}
+
+/// Construct `Stage`'s class.
+pub fn create_class<'gc>(mc: MutationContext<'gc, '_>) -> GcCell<'gc, Class<'gc>> {
+    let class = Class::new(
+        QName::new(Namespace::package("flash.display"), "Stage"),
+        Some(
+            QName::new(
+                Namespace::package("flash.display"),
+                "DisplayObjectContainer",
+            )
+            .into(),
+        ),
+        Method::from_builtin(instance_init),
+        Method::from_builtin(class_init),
+        mc,
+    );
+
+    let mut write = class.write(mc);
+
+    write.set_attributes(ClassAttributes::SEALED);
+
+    class
+}