Plan display file actions in app core

src/app_core/document_platform_io.h

@@ -9,6 +9,11 @@ enum class PickedPathAction {
     invoke_callback,
 };
 
+enum class DisplayFileAction {
+    ignore_empty_path,
+    open_external_file,
+};
+
 [[nodiscard]] constexpr PickedPathAction plan_picked_path(std::string_view path) noexcept
 {
     return path.empty()
@@ -16,4 +21,11 @@ enum class PickedPathAction {
         : PickedPathAction::invoke_callback;
 }
 
+[[nodiscard]] constexpr DisplayFileAction plan_display_file(std::string_view path) noexcept
+{
+    return path.empty()
+        ? DisplayFileAction::ignore_empty_path
+        : DisplayFileAction::open_external_file;
+}
+
 }

src/app_events.cpp

@@ -311,6 +311,9 @@ void App::pick_dir(std::function<void(std::string path)> callback)
 
 void App::display_file(std::string path)
 {
+    if (pp::app::plan_display_file(path) == pp::app::DisplayFileAction::ignore_empty_path)
+        return;
+
 #ifdef __IOS__
     dispatch_async(dispatch_get_main_queue(), ^{
         [ios_view display_file:path];