[Web] Expose API to force file system sync.

Mostly useful for modules and extensions that can't use FileAccess to
write files.

doc/classes/JavaScriptBridge.xml

@@ -46,6 +46,13 @@
 				If [param use_global_execution_context] is [code]true[/code], the code will be evaluated in the global execution context. Otherwise, it is evaluated in the execution context of a function within the engine's runtime environment.
 			</description>
 		</method>
+		<method name="force_fs_sync">
+			<return type="void" />
+			<description>
+				Force synchronization of the persistent file system (when enabled).
+				[b]Note:[/b] This is only useful for modules or extensions that can't use [FileAccess] to write files.
+			</description>
+		</method>
 		<method name="get_interface">
 			<return type="JavaScriptObject" />
 			<param index="0" name="interface" type="String" />

platform/web/api/api.cpp

@@ -73,6 +73,7 @@ void JavaScriptBridge::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("download_buffer", "buffer", "name", "mime"), &JavaScriptBridge::download_buffer, DEFVAL("application/octet-stream"));
 	ClassDB::bind_method(D_METHOD("pwa_needs_update"), &JavaScriptBridge::pwa_needs_update);
 	ClassDB::bind_method(D_METHOD("pwa_update"), &JavaScriptBridge::pwa_update);
+	ClassDB::bind_method(D_METHOD("force_fs_sync"), &JavaScriptBridge::force_fs_sync);
 	ADD_SIGNAL(MethodInfo("pwa_update_available"));
 }
 
@@ -111,6 +112,8 @@ bool JavaScriptBridge::pwa_needs_update() const {
 Error JavaScriptBridge::pwa_update() {
 	return ERR_UNAVAILABLE;
 }
+void JavaScriptBridge::force_fs_sync() {
+}
 void JavaScriptBridge::download_buffer(Vector<uint8_t> p_arr, const String &p_name, const String &p_mime) {
 }
 #endif

platform/web/api/javascript_bridge_singleton.h

@@ -61,6 +61,7 @@ public:
 	void download_buffer(Vector<uint8_t> p_arr, const String &p_name, const String &p_mime = "application/octet-stream");
 	bool pwa_needs_update() const;
 	Error pwa_update();
+	void force_fs_sync();
 
 	static JavaScriptBridge *get_singleton();
 	JavaScriptBridge();

platform/web/javascript_bridge_singleton.cpp

@@ -361,6 +361,11 @@ void JavaScriptBridge::download_buffer(Vector<uint8_t> p_arr, const String &p_na
 bool JavaScriptBridge::pwa_needs_update() const {
 	return OS_Web::get_singleton()->pwa_needs_update();
 }
+
 Error JavaScriptBridge::pwa_update() {
 	return OS_Web::get_singleton()->pwa_update();
 }
+
+void JavaScriptBridge::force_fs_sync() {
+	OS_Web::get_singleton()->force_fs_sync();
+}

platform/web/os_web.cpp

@@ -196,6 +196,12 @@ void OS_Web::update_pwa_state_callback() {
 	}
 }
 
+void OS_Web::force_fs_sync() {
+	if (is_userfs_persistent()) {
+		idb_needs_sync = true;
+	}
+}
+
 Error OS_Web::pwa_update() {
 	return godot_js_pwa_update() ? FAILED : OK;
 }

platform/web/os_web.h

@@ -69,6 +69,7 @@ public:
 
 	bool pwa_needs_update() const { return pwa_is_waiting; }
 	Error pwa_update();
+	void force_fs_sync();
 
 	void initialize_joypads() override;