From ee4b47d0622302d0d879ddd79d07bcb3eba290d0 Mon Sep 17 00:00:00 2001
From: David Wendt <dcrkid@yahoo.com>
Date: Mon, 28 Oct 2019 18:13:29 -0400
Subject: [PATCH] Add interface support, and add interface checking to
 `ActionInstanceOf`.

---
 core/src/avm1.rs               | 35 ++++++++++++++--------------------
 core/src/avm1/object.rs        | 10 ++++++++++
 core/src/avm1/script_object.rs | 15 +++++++++++++++
 core/src/avm1/stage_object.rs  |  8 ++++++++
 4 files changed, 47 insertions(+), 21 deletions(-)

diff --git a/core/src/avm1.rs b/core/src/avm1.rs
index 9d65e11ce..0071a82f9 100644
--- a/core/src/avm1.rs
+++ b/core/src/avm1.rs
@@ -1041,28 +1041,13 @@ impl<'gc> Avm1<'gc> {
 
         //TODO: What happens if we try to extend an object which has no `__proto__`?
         //e.g. `class Whatever extends Object.prototype`
-        let super_proto = superclass.read().proto().unwrap_or(self.prototypes.object);
+        let super_proto = superclass.proto().unwrap_or(self.prototypes.object);
 
-        let sub_prototype = GcCell::allocate(
-            context.gc_context,
-            Box::new(ScriptObject::object(context.gc_context, Some(super_proto)))
-                as Box<dyn Object<'gc>>,
-        );
+        let sub_prototype: Object<'gc> =
+            ScriptObject::object(context.gc_context, Some(super_proto)).into();
 
-        sub_prototype.write(context.gc_context).set(
-            "constructor",
-            superclass.into(),
-            self,
-            context,
-            sub_prototype,
-        )?;
-        subclass.write(context.gc_context).set(
-            "prototype",
-            sub_prototype.into(),
-            self,
-            context,
-            subclass,
-        )?;
+        sub_prototype.set("constructor", superclass.into(), self, context)?;
+        subclass.set("prototype", sub_prototype.into(), self, context)?;
 
         Ok(())
     }
@@ -1364,7 +1349,6 @@ impl<'gc> Avm1<'gc> {
         let constr = self.pop()?.as_object()?;
         let obj = self.pop()?.as_object()?;
 
-        //TODO: Interface detection on SWF7
         let prototype = constr
             .get("prototype", self, context)?
             .resolve(self, context)?
@@ -1377,6 +1361,15 @@ impl<'gc> Avm1<'gc> {
                 return Ok(());
             }
 
+            if self.current_swf_version() >= 7 {
+                for interface in constr.interfaces() {
+                    if Object::ptr_eq(interface, constr) {
+                        self.push(true);
+                        return Ok(());
+                    }
+                }
+            }
+
             proto = this_proto.proto();
         }
 
diff --git a/core/src/avm1/object.rs b/core/src/avm1/object.rs
index ed8562d5f..490a78a25 100644
--- a/core/src/avm1/object.rs
+++ b/core/src/avm1/object.rs
@@ -165,6 +165,16 @@ pub trait TObject<'gc>: 'gc + Collect + Debug + Into<Object<'gc>> + Clone + Copy
     /// Get the object's type string.
     fn type_of(&self) -> &'static str;
 
+    /// Enumerate all interfaces implemented by this object.
+    fn interfaces(&self) -> Vec<Object<'gc>>;
+
+    /// Set the interface list for this object. (Only useful for prototypes.)
+    fn set_interfaces(
+        &mut self,
+        gc_context: MutationContext<'gc, '_>,
+        iface_list: Vec<Object<'gc>>,
+    );
+
     /// Get the underlying script object, if it exists.
     fn as_script_object(&self) -> Option<ScriptObject<'gc>>;
 
diff --git a/core/src/avm1/script_object.rs b/core/src/avm1/script_object.rs
index 131694430..46490be6d 100644
--- a/core/src/avm1/script_object.rs
+++ b/core/src/avm1/script_object.rs
@@ -27,6 +27,7 @@ pub struct ScriptObjectData<'gc> {
     prototype: Option<Object<'gc>>,
     values: HashMap<String, Property<'gc>>,
     function: Option<Executable<'gc>>,
+    interfaces: Vec<Object<'gc>>,
     type_of: &'static str,
     array: ArrayStorage<'gc>,
 }
@@ -37,6 +38,7 @@ unsafe impl<'gc> Collect for ScriptObjectData<'gc> {
         self.values.trace(cc);
         self.function.trace(cc);
         self.array.trace(cc);
+        self.interfaces.trace(cc);
     }
 }
 
@@ -64,6 +66,7 @@ impl<'gc> ScriptObject<'gc> {
                 values: HashMap::new(),
                 function: None,
                 array: ArrayStorage::Properties { length: 0 },
+                interfaces: vec![],
             },
         ))
     }
@@ -80,6 +83,7 @@ impl<'gc> ScriptObject<'gc> {
                 values: HashMap::new(),
                 function: None,
                 array: ArrayStorage::Vector(Vec::new()),
+                interfaces: vec![],
             },
         ));
         object.sync_native_property("length", gc_context, Some(0.into()));
@@ -99,6 +103,7 @@ impl<'gc> ScriptObject<'gc> {
                 values: HashMap::new(),
                 function: None,
                 array: ArrayStorage::Properties { length: 0 },
+                interfaces: vec![],
             },
         ))
         .into()
@@ -118,6 +123,7 @@ impl<'gc> ScriptObject<'gc> {
                 values: HashMap::new(),
                 function: None,
                 array: ArrayStorage::Properties { length: 0 },
+                interfaces: vec![],
             },
         ))
     }
@@ -136,6 +142,7 @@ impl<'gc> ScriptObject<'gc> {
                 function: Some(function.into()),
                 values: HashMap::new(),
                 array: ArrayStorage::Properties { length: 0 },
+                interfaces: vec![],
             },
         ))
     }
@@ -465,6 +472,14 @@ impl<'gc> TObject<'gc> for ScriptObject<'gc> {
         self.0.read().type_of
     }
 
+    fn interfaces(&self) -> Vec<Object<'gc>> {
+        self.0.read().interfaces.clone()
+    }
+
+    fn set_interfaces(&mut self, context: MutationContext<'gc, '_>, iface_list: Vec<Object<'gc>>) {
+        self.0.write(context).interfaces = iface_list;
+    }
+
     fn as_script_object(&self) -> Option<ScriptObject<'gc>> {
         Some(*self)
     }
diff --git a/core/src/avm1/stage_object.rs b/core/src/avm1/stage_object.rs
index c27eb5351..2aad83704 100644
--- a/core/src/avm1/stage_object.rs
+++ b/core/src/avm1/stage_object.rs
@@ -228,6 +228,14 @@ impl<'gc> TObject<'gc> for StageObject<'gc> {
         self.base.delete_array_element(index, gc_context)
     }
 
+    fn interfaces(&self) -> Vec<Object<'gc>> {
+        self.base.interfaces()
+    }
+
+    fn set_interfaces(&mut self, context: MutationContext<'gc, '_>, iface_list: Vec<Object<'gc>>) {
+        self.base.set_interfaces(context, iface_list)
+    }
+
     fn as_string(&self) -> String {
         self.display_object.path()
     }