core: Add ability to call out to ExternalInterfaceProviders

core/src/avm1/globals/external_interface.rs

@@ -41,6 +41,21 @@ pub fn add_callback<'gc>(
     }
 }
 
+pub fn call<'gc>(
+    activation: &mut Activation<'_, 'gc, '_>,
+    _this: Object<'gc>,
+    args: &[Value<'gc>],
+) -> Result<Value<'gc>, Error<'gc>> {
+    if args.is_empty() {
+        return Ok(Value::Null);
+    }
+
+    let name = args.get(0).unwrap().coerce_to_string(activation)?;
+    activation.context.external_interface.call_external(&name);
+
+    Ok(Value::Null)
+}
+
 pub fn create_external_interface_object<'gc>(
     gc_context: MutationContext<'gc, '_>,
     proto: Object<'gc>,
@@ -69,6 +84,14 @@ pub fn create_external_interface_object<'gc>(
         Some(fn_proto),
     );
 
+    object.force_set_function(
+        "call",
+        call,
+        gc_context,
+        Attribute::DontDelete | Attribute::DontEnum,
+        Some(fn_proto),
+    );
+
     object.into()
 }
 

core/src/external.rs

@@ -36,7 +36,9 @@ impl<'gc> Callback<'gc> {
     }
 }
 
-pub trait ExternalInterfaceProvider {}
+pub trait ExternalInterfaceProvider {
+    fn call(&self, name: &str) -> Option<()>;
+}
 
 #[derive(Default)]
 pub struct ExternalInterface<'gc> {
@@ -68,6 +70,14 @@ impl<'gc> ExternalInterface<'gc> {
         self.callbacks.get(name).cloned()
     }
 
+    pub fn call_external(&self, name: &str) {
+        for provider in &self.providers {
+            if provider.call(name).is_some() {
+                return;
+            }
+        }
+    }
+
     pub fn available(&self) -> bool {
         !self.providers.is_empty()
     }

core/tests/regression_tests.rs

@@ -546,4 +546,14 @@ impl ExternalInterfaceTestProvider {
     }
 }
 
-impl ExternalInterfaceProvider for ExternalInterfaceTestProvider {}
+impl ExternalInterfaceProvider for ExternalInterfaceTestProvider {
+    fn call(&self, name: &str) -> Option<()> {
+        match name {
+            "ping" => {
+                log::info!(target: "avm_trace", "[ExternalInterface] ping");
+                Some(())
+            }
+            _ => None,
+        }
+    }
+}

core/tests/swfs/avm1/external_interface/output.txt

@@ -4,6 +4,16 @@ true
 // ExternalInterface.addCallback("dump", object, dump)
 true
 
+// ExternalInterface.call()
+null
+
+// ExternalInterface.call("ping")
+[ExternalInterface] ping
+null
+
+// ExternalInterface.call("non_existent")
+null
+
 /// dump() start
 // this
 [object Object]