[HTML5] Implement JavaScript PWA update callbacks.

Allows detecting when a new version of the progressive web app service
worker is waiting (i.e. an update is pending), along a function to force
the update and reload all clients.

doc/classes/JavaScript.xml

@@ -53,5 +53,27 @@
 				Returns an interface to a JavaScript object that can be used by scripts. The [code]interface[/code] must be a valid property of the JavaScript [code]window[/code]. The callback must accept a single [Array] argument, which will contain the JavaScript [code]arguments[/code]. See [JavaScriptObject] for usage.
 			</description>
 		</method>
+		<method name="pwa_needs_update" qualifiers="const">
+			<return type="bool" />
+			<description>
+				Returns [code]true[/code] if a new version of the progressive web app is waiting to be activated.
+				[b]Note:[/b] Only relevant when exported as a Progressive Web App.
+			</description>
+		</method>
+		<method name="pwa_update">
+			<return type="int" enum="Error" />
+			<description>
+				Performs the live update of the progressive web app. Forcing the new version to be installed and the page to be reloaded.
+				[b]Note:[/b] Your application will be [b]reloaded in all browser tabs[/b].
+				[b]Note:[/b] Only relevant when exported as a Progressive Web App and [method pwa_needs_update] returns [code]true[/code].
+			</description>
+		</method>
 	</methods>
+	<signals>
+		<signal name="pwa_update_available">
+			<description>
+				Emitted when an update for this progressive web app has been detected but is waiting to be activated because a previous version is active. See [method pwa_update] to force the update to take place immediately.
+			</description>
+		</signal>
+	</signals>
 </class>

platform/javascript/api/api.cpp

@@ -71,6 +71,9 @@ void JavaScript::_bind_methods() {
 		ClassDB::bind_vararg_method(METHOD_FLAGS_DEFAULT, "create_object", &JavaScript::_create_object_bind, mi);
 	}
 	ClassDB::bind_method(D_METHOD("download_buffer", "buffer", "name", "mime"), &JavaScript::download_buffer, DEFVAL("application/octet-stream"));
+	ClassDB::bind_method(D_METHOD("pwa_needs_update"), &JavaScript::pwa_needs_update);
+	ClassDB::bind_method(D_METHOD("pwa_update"), &JavaScript::pwa_update);
+	ADD_SIGNAL(MethodInfo("pwa_update_available"));
 }
 
 #if !defined(JAVASCRIPT_ENABLED) || !defined(JAVASCRIPT_EVAL_ENABLED)
@@ -102,6 +105,12 @@ Variant JavaScript::_create_object_bind(const Variant **p_args, int p_argcount,
 }
 #endif
 #if !defined(JAVASCRIPT_ENABLED)
+bool JavaScript::pwa_needs_update() const {
+	return false;
+}
+Error JavaScript::pwa_update() {
+	return ERR_UNAVAILABLE;
+}
 void JavaScript::download_buffer(Vector<uint8_t> p_arr, const String &p_name, const String &p_mime) {
 }
 #endif

platform/javascript/api/javascript_singleton.h

@@ -59,6 +59,8 @@ public:
 	Ref<JavaScriptObject> create_callback(const Callable &p_callable);
 	Variant _create_object_bind(const Variant **p_args, int p_argcount, Callable::CallError &r_error);
 	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();
 
 	static JavaScript *get_singleton();
 	JavaScript();

platform/javascript/godot_js.h

@@ -49,6 +49,8 @@ extern void godot_js_os_fs_sync(void (*p_callback)());
 extern int godot_js_os_execute(const char *p_json);
 extern void godot_js_os_shell_open(const char *p_uri);
 extern int godot_js_os_hw_concurrency_get();
+extern int godot_js_pwa_cb(void (*p_callback)());
+extern int godot_js_pwa_update();
 
 // Input
 extern void godot_js_input_mouse_button_cb(int (*p_callback)(int p_pressed, int p_button, double p_x, double p_y, int p_modifiers));

platform/javascript/javascript_singleton.cpp

@@ -30,6 +30,7 @@
 
 #include "api/javascript_singleton.h"
 #include "emscripten.h"
+#include "os_javascript.h"
 
 extern "C" {
 extern void godot_js_os_download_buffer(const uint8_t *p_buf, int p_buf_size, const char *p_name, const char *p_mime);
@@ -355,3 +356,10 @@ Variant JavaScript::eval(const String &p_code, bool p_use_global_exec_context) {
 void JavaScript::download_buffer(Vector<uint8_t> p_arr, const String &p_name, const String &p_mime) {
 	godot_js_os_download_buffer(p_arr.ptr(), p_arr.size(), p_name.utf8().get_data(), p_mime.utf8().get_data());
 }
+
+bool JavaScript::pwa_needs_update() const {
+	return OS_JavaScript::get_singleton()->pwa_needs_update();
+}
+Error JavaScript::pwa_update() {
+	return OS_JavaScript::get_singleton()->pwa_update();
+}

platform/javascript/js/libs/library_godot_os.js

@@ -368,3 +368,58 @@ const GodotEventListeners = {
 	},
 };
 mergeInto(LibraryManager.library, GodotEventListeners);
+
+const GodotPWA = {
+
+	$GodotPWA__deps: ['$GodotRuntime', '$GodotEventListeners'],
+	$GodotPWA: {
+		hasUpdate: false,
+
+		updateState: function (cb, reg) {
+			if (!reg) {
+				return;
+			}
+			if (!reg.active) {
+				return;
+			}
+			if (reg.waiting) {
+				GodotPWA.hasUpdate = true;
+				cb();
+			}
+			GodotEventListeners.add(reg, 'updatefound', function () {
+				const installing = reg.installing;
+				GodotEventListeners.add(installing, 'statechange', function () {
+					if (installing.state === 'installed') {
+						GodotPWA.hasUpdate = true;
+						cb();
+					}
+				});
+			});
+		},
+	},
+
+	godot_js_pwa_cb__sig: 'vi',
+	godot_js_pwa_cb: function (p_update_cb) {
+		if ('serviceWorker' in navigator) {
+			const cb = GodotRuntime.get_func(p_update_cb);
+			navigator.serviceWorker.getRegistration().then(GodotPWA.updateState.bind(null, cb));
+		}
+	},
+
+	godot_js_pwa_update__sig: 'i',
+	godot_js_pwa_update: function () {
+		if ('serviceWorker' in navigator && GodotPWA.hasUpdate) {
+			navigator.serviceWorker.getRegistration().then(function (reg) {
+				if (!reg || !reg.waiting) {
+					return;
+				}
+				reg.waiting.postMessage('update');
+			});
+			return 0;
+		}
+		return 1;
+	},
+};
+
+autoAddDeps(GodotPWA, '$GodotPWA');
+mergeInto(LibraryManager.library, GodotPWA);

platform/javascript/os_javascript.cpp

@@ -45,6 +45,7 @@
 #include <emscripten.h>
 #include <stdlib.h>
 
+#include "api/javascript_singleton.h"
 #include "godot_js.h"
 
 void OS_JavaScript::alert(const String &p_alert, const String &p_title) {
@@ -203,6 +204,19 @@ void OS_JavaScript::file_access_close_callback(const String &p_file, int p_flags
 	}
 }
 
+void OS_JavaScript::update_pwa_state_callback() {
+	if (OS_JavaScript::get_singleton()) {
+		OS_JavaScript::get_singleton()->pwa_is_waiting = true;
+	}
+	if (JavaScript::get_singleton()) {
+		JavaScript::get_singleton()->emit_signal("pwa_update_available");
+	}
+}
+
+Error OS_JavaScript::pwa_update() {
+	return godot_js_pwa_update() ? FAILED : OK;
+}
+
 bool OS_JavaScript::is_userfs_persistent() const {
 	return idb_available;
 }
@@ -226,6 +240,8 @@ OS_JavaScript::OS_JavaScript() {
 	godot_js_config_locale_get(locale_ptr, 16);
 	setenv("LANG", locale_ptr, true);
 
+	godot_js_pwa_cb(&OS_JavaScript::update_pwa_state_callback);
+
 	if (AudioDriverJavaScript::is_available()) {
 #ifdef NO_THREADS
 		audio_drivers.push_back(memnew(AudioDriverScriptProcessor));

platform/javascript/os_javascript.h

@@ -45,11 +45,13 @@ class OS_JavaScript : public OS_Unix {
 	bool idb_is_syncing = false;
 	bool idb_available = false;
 	bool idb_needs_sync = false;
+	bool pwa_is_waiting = false;
 
 	static void main_loop_callback();
 
 	static void file_access_close_callback(const String &p_file, int p_flags);
 	static void fs_sync_callback();
+	static void update_pwa_state_callback();
 
 protected:
 	void initialize() override;
@@ -65,6 +67,9 @@ public:
 	// Override return type to make writing static callbacks less tedious.
 	static OS_JavaScript *get_singleton();
 
+	bool pwa_needs_update() const { return pwa_is_waiting; }
+	Error pwa_update();
+
 	void initialize_joypads() override;
 
 	MainLoop *get_main_loop() const override;