core: Move fscommand execution outside of ExternalInterfaceProvider, so it can be implemented without causing ExternalInterface.available to become true

core/src/external.rs

@@ -309,12 +309,22 @@ impl<'gc> Callback<'gc> {
     }
 }
 
+pub trait FsCommandProvider {
+    fn on_fs_command(&self, command: &str, args: &str) -> bool;
+}
+
+pub struct NullFsCommandProvider;
+
+impl FsCommandProvider for NullFsCommandProvider {
+    fn on_fs_command(&self, _command: &str, _args: &str) -> bool {
+        false
+    }
+}
+
 pub trait ExternalInterfaceProvider {
     fn get_method(&self, name: &str) -> Option<Box<dyn ExternalInterfaceMethod>>;
 
     fn on_callback_available(&self, name: &str);
-
-    fn on_fs_command(&self, command: &str, args: &str) -> bool;
 }
 
 pub trait ExternalInterfaceMethod {
@@ -330,19 +340,25 @@ where
     }
 }
 
-#[derive(Default, Collect)]
+#[derive(Collect)]
 #[collect(no_drop)]
 pub struct ExternalInterface<'gc> {
     #[collect(require_static)]
     providers: Vec<Box<dyn ExternalInterfaceProvider>>,
     callbacks: BTreeMap<String, Callback<'gc>>,
+    #[collect(require_static)]
+    fs_commands: Box<dyn FsCommandProvider>,
 }
 
 impl<'gc> ExternalInterface<'gc> {
-    pub fn new(providers: Vec<Box<dyn ExternalInterfaceProvider>>) -> Self {
+    pub fn new(
+        providers: Vec<Box<dyn ExternalInterfaceProvider>>,
+        fs_commands: Box<dyn FsCommandProvider>,
+    ) -> Self {
         Self {
             providers,
-            ..Default::default()
+            callbacks: Default::default(),
+            fs_commands,
         }
     }
 
@@ -375,11 +391,6 @@ impl<'gc> ExternalInterface<'gc> {
     }
 
     pub fn invoke_fs_command(&self, command: &str, args: &str) -> bool {
-        for provider in &self.providers {
-            if provider.on_fs_command(command, args) {
-                return true;
-            }
-        }
-        false
+        self.fs_commands.on_fs_command(command, args)
     }
 }

core/src/player.rs

@@ -30,8 +30,8 @@ use crate::display_object::{
     TInteractiveObject, WindowMode,
 };
 use crate::events::{ButtonKeyCode, ClipEvent, ClipEventResult, KeyCode, MouseButton, PlayerEvent};
-use crate::external::Value as ExternalValue;
-use crate::external::{ExternalInterface, ExternalInterfaceProvider};
+use crate::external::{ExternalInterface, ExternalInterfaceProvider, NullFsCommandProvider};
+use crate::external::{FsCommandProvider, Value as ExternalValue};
 use crate::focus_tracker::FocusTracker;
 use crate::font::Font;
 use crate::frame_lifecycle::{run_all_phases_avm2, FramePhase};
@@ -2110,6 +2110,7 @@ pub struct PlayerBuilder {
     sandbox_type: SandboxType,
     frame_rate: Option<f64>,
     external_interface_providers: Vec<Box<dyn ExternalInterfaceProvider>>,
+    fs_command_provider: Box<dyn FsCommandProvider>,
 }
 
 impl PlayerBuilder {
@@ -2154,6 +2155,7 @@ impl PlayerBuilder {
             sandbox_type: SandboxType::LocalTrusted,
             frame_rate: None,
             external_interface_providers: vec![],
+            fs_command_provider: Box::new(NullFsCommandProvider),
         }
     }
 
@@ -2318,12 +2320,19 @@ impl PlayerBuilder {
         self
     }
 
+    /// Adds an FSCommand implementation for movies to communicate with
+    pub fn with_fs_commands(mut self, provider: Box<dyn FsCommandProvider>) -> Self {
+        self.fs_command_provider = provider;
+        self
+    }
+
     fn create_gc_root<'gc>(
         gc_context: &'gc gc_arena::Mutation<'gc>,
         player_version: u8,
         fullscreen: bool,
         fake_movie: Arc<SwfMovie>,
         external_interface_providers: Vec<Box<dyn ExternalInterfaceProvider>>,
+        fs_command_provider: Box<dyn FsCommandProvider>,
     ) -> GcRoot<'gc> {
         let mut interner = AvmStringInterner::new();
         let mut init = GcContext {
@@ -2344,7 +2353,10 @@ impl PlayerBuilder {
                     interner,
                     current_context_menu: None,
                     drag_object: None,
-                    external_interface: ExternalInterface::new(external_interface_providers),
+                    external_interface: ExternalInterface::new(
+                        external_interface_providers,
+                        fs_command_provider,
+                    ),
                     focus_tracker: FocusTracker::new(gc_context),
                     library: Library::empty(),
                     load_manager: LoadManager::new(),
@@ -2459,6 +2471,7 @@ impl PlayerBuilder {
                             self.fullscreen,
                             fake_movie.clone(),
                             self.external_interface_providers,
+                            self.fs_command_provider,
                         )
                     },
                 ))),

desktop/src/backends/external_interface.rs

@@ -9,8 +9,4 @@ impl ExternalInterfaceProvider for DesktopExternalInterfaceProvider {
     }
 
     fn on_callback_available(&self, _name: &str) {}
-
-    fn on_fs_command(&self, _command: &str, _args: &str) -> bool {
-        false
-    }
 }

tests/tests/external_interface/mod.rs

@@ -47,8 +47,4 @@ impl ExternalInterfaceProvider for ExternalInterfaceTestProvider {
     }
 
     fn on_callback_available(&self, _name: &str) {}
-
-    fn on_fs_command(&self, _command: &str, _args: &str) -> bool {
-        false
-    }
 }

web/src/lib.rs

@@ -15,7 +15,8 @@ use ruffle_core::config::{Letterbox, NetworkingAccessMode};
 use ruffle_core::context::UpdateContext;
 use ruffle_core::events::{KeyCode, MouseButton, MouseWheelDelta, TextControlCode};
 use ruffle_core::external::{
-    ExternalInterfaceMethod, ExternalInterfaceProvider, Value as ExternalValue, Value,
+    ExternalInterfaceMethod, ExternalInterfaceProvider, FsCommandProvider, Value as ExternalValue,
+    Value,
 };
 use ruffle_core::tag_utils::SwfMovie;
 use ruffle_core::{
@@ -1436,7 +1437,9 @@ impl ExternalInterfaceProvider for JavascriptInterface {
     fn on_callback_available(&self, name: &str) {
         self.js_player.on_callback_available(name);
     }
+}
 
+impl FsCommandProvider for JavascriptInterface {
     fn on_fs_command(&self, command: &str, args: &str) -> bool {
         self.js_player
             .on_fs_command(command, args)