core: Add error for loading invalid SWF files and display as appropriate

core/src/backend/ui.rs

@@ -81,7 +81,7 @@ pub trait UiBackend: Downcast {
     /// Displays a message about an error during root movie download.
     /// In particular, on web this can be a CORS error, which we can sidestep
     /// by providing a direct .swf link instead.
-    fn display_root_movie_download_failed_message(&self);
+    fn display_root_movie_download_failed_message(&self, _invalid_swf: bool);
 
     // Unused, but kept in case we need it later.
     fn message(&self, message: &str);
@@ -275,7 +275,7 @@ impl UiBackend for NullUiBackend {
         Ok(())
     }
 
-    fn display_root_movie_download_failed_message(&self) {}
+    fn display_root_movie_download_failed_message(&self, _invalid_swf: bool) {}
 
     fn message(&self, _message: &str) {}
 

core/src/loader.rs

@@ -821,7 +821,7 @@ impl<'gc> Loader<'gc> {
                     .lock()
                     .unwrap()
                     .ui()
-                    .display_root_movie_download_failed_message();
+                    .display_root_movie_download_failed_message(false);
                 error.error
             })?;
 
@@ -844,7 +844,7 @@ impl<'gc> Loader<'gc> {
                         .lock()
                         .unwrap()
                         .ui()
-                        .display_root_movie_download_failed_message();
+                        .display_root_movie_download_failed_message(true);
                     error
                 })?;
             on_metadata(movie.header());

desktop/src/backends/ui.rs

@@ -196,7 +196,7 @@ impl UiBackend for DesktopUiBackend {
         Ok(())
     }
 
-    fn display_root_movie_download_failed_message(&self) {
+    fn display_root_movie_download_failed_message(&self, _invalid_swf: bool) {
         let dialog = MessageDialog::new()
             .set_level(MessageLevel::Warning)
             .set_title("Ruffle - Load failed")

tests/framework/src/backends/ui.rs

@@ -113,7 +113,7 @@ impl UiBackend for TestUiBackend {
         Ok(())
     }
 
-    fn display_root_movie_download_failed_message(&self) {}
+    fn display_root_movie_download_failed_message(&self, _invalid_swf: bool) {}
 
     fn message(&self, _message: &str) {}
 

web/packages/core/src/ruffle-player.ts

@@ -35,6 +35,7 @@ enum PanicError {
     WasmMimeType,
     WasmNotFound,
     WasmDisabledMicrosoftEdge,
+    InvalidSwf,
     SwfFetchError,
     SwfCors,
 }
@@ -2114,6 +2115,10 @@ export class RufflePlayer extends HTMLElement {
                     new PanicLinkInfo(),
                 ]);
                 break;
+            case PanicError.InvalidSwf:
+                errorBody = textAsParagraphs("error-invalid-swf");
+                errorFooter = this.createErrorFooter([new PanicLinkInfo()]);
+                break;
             case PanicError.SwfFetchError:
                 errorBody = textAsParagraphs("error-swf-fetch");
                 errorFooter = this.createErrorFooter([new PanicLinkInfo()]);
@@ -2244,10 +2249,14 @@ export class RufflePlayer extends HTMLElement {
         this.destroy();
     }
 
-    protected displayRootMovieDownloadFailedMessage(): void {
+    protected displayRootMovieDownloadFailedMessage(invalidSwf: boolean): void {
         const openInNewTab = this.loadedConfig?.openInNewTab;
-        if (openInNewTab && window.location.origin !== this.swfUrl!.origin) {
+        if (
-            const url = new URL(this.swfUrl!);
+            openInNewTab &&
+            this.swfUrl &&
+            window.location.origin !== this.swfUrl.origin
+        ) {
+            const url = new URL(this.swfUrl);
             if (this.loadedConfig?.parameters) {
                 const parameters = sanitizeParameters(
                     this.loadedConfig?.parameters,
@@ -2275,10 +2284,12 @@ export class RufflePlayer extends HTMLElement {
             this.container.prepend(div);
         } else {
             const error = new Error("Failed to fetch: " + this.swfUrl);
-            if (!this.swfUrl!.protocol.includes("http")) {
+            if (this.swfUrl && !this.swfUrl.protocol.includes("http")) {
                 error.ruffleIndexError = PanicError.FileProtocol;
+            } else if (invalidSwf) {
+                error.ruffleIndexError = PanicError.InvalidSwf;
             } else if (
-                window.location.origin === this.swfUrl!.origin ||
+                window.location.origin === this.swfUrl?.origin ||
                 // The extension's internal player page is not restricted by CORS
                 window.location.protocol.includes("extension")
             ) {

web/packages/core/texts/en-US/messages.ftl

@@ -30,6 +30,9 @@ error-wasm-mime-type =
     Ruffle has encountered a major issue whilst trying to initialize.
     This web server is not serving ".wasm" files with the correct MIME type.
     If you are the server administrator, please consult the Ruffle wiki for help.
+error-invalid-swf =
+    Ruffle cannot parse the requested file.
+    The most likely reason is that the requested file is not a valid SWF.
 error-swf-fetch =
     Ruffle failed to load the Flash SWF file.
     The most likely reason is that the file no longer exists, so there is nothing for Ruffle to load.

web/src/lib.rs

@@ -105,7 +105,7 @@ extern "C" {
     fn panic(this: &JavascriptPlayer, error: &JsError);
 
     #[wasm_bindgen(method, js_name = "displayRootMovieDownloadFailedMessage")]
-    fn display_root_movie_download_failed_message(this: &JavascriptPlayer);
+    fn display_root_movie_download_failed_message(this: &JavascriptPlayer, invalid_swf: bool);
 
     #[wasm_bindgen(method, js_name = "displayMessage")]
     fn display_message(this: &JavascriptPlayer, message: &str);
@@ -401,8 +401,14 @@ impl Ruffle {
             segments.push(&swf_name);
         }
 
-        let mut movie = SwfMovie::from_data(&swf_data.to_vec(), url.to_string(), None)
+        let mut movie =
-            .map_err(|e| format!("Error loading movie: {e}"))?;
+            SwfMovie::from_data(&swf_data.to_vec(), url.to_string(), None).map_err(|e| {
+                let _ = self.with_core_mut(|core| {
+                    core.ui_mut()
+                        .display_root_movie_download_failed_message(true);
+                });
+                format!("Error loading movie: {e}")
+            })?;
         movie.append_parameters(parse_movie_parameters(&parameters));
 
         self.on_metadata(movie.header());

web/src/ui.rs

@@ -240,8 +240,9 @@ impl UiBackend for WebUiBackend {
         }
     }
 
-    fn display_root_movie_download_failed_message(&self) {
+    fn display_root_movie_download_failed_message(&self, invalid_swf: bool) {
-        self.js_player.display_root_movie_download_failed_message()
+        self.js_player
+            .display_root_movie_download_failed_message(invalid_swf)
     }
 
     fn message(&self, message: &str) {