wpe: Add 'run-javascript' action signal

Introduce way of running a script in the context of the internal
webView.

Fixes #1722

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/3753>

subprojects/gst-plugins-bad/ext/wpe/WPEThreadedView.cpp

@@ -695,6 +695,27 @@ void WPEView::loadUri(const gchar* uri)
     });
 }
 
+static void s_runJavascriptFinished(GObject* object, GAsyncResult* result, gpointer user_data)
+{
+    WebKitJavascriptResult* js_result;
+    GError* error = NULL;
+
+    js_result = webkit_web_view_run_javascript_finish(WEBKIT_WEB_VIEW(object), result, &error);
+    if (!js_result) {
+        GST_WARNING("Error running javascript: %s", error->message);
+        g_error_free(error);
+        return;
+    }
+    webkit_javascript_result_unref(js_result);
+}
+
+void WPEView::runJavascript(const char* script)
+{
+    s_view->dispatch([&]() {
+        webkit_web_view_run_javascript(webkit.view, script, nullptr, s_runJavascriptFinished, nullptr);
+    });
+}
+
 void WPEView::loadData(GBytes* bytes)
 {
     s_view->dispatch([this, bytes = g_bytes_ref(bytes)]() {

subprojects/gst-plugins-bad/ext/wpe/WPEThreadedView.h

@@ -43,6 +43,7 @@ public:
     void resize(int width, int height);
     void loadUri(const gchar*);
     void loadData(GBytes*);
+    void runJavascript(const gchar*);
     void setDrawBackground(gboolean);
 
     GstEGLImage* image();

subprojects/gst-plugins-bad/ext/wpe/gstwpesrcbin.cpp

@@ -150,6 +150,7 @@ enum
 enum
 {
  SIGNAL_LOAD_BYTES,
+ SIGNAL_RUN_JAVASCRIPT,
  LAST_SIGNAL
 };
 
@@ -341,6 +342,15 @@ gst_wpe_src_load_bytes (GstWpeVideoSrc * src, GBytes * bytes)
     g_signal_emit_by_name (self->video_src, "load-bytes", bytes, NULL);
 }
 
+static void
+gst_wpe_src_run_javascript (GstWpeVideoSrc * src, const gchar * script)
+{
+  GstWpeSrc *self = GST_WPE_SRC (src);
+
+  if (self->video_src)
+    g_signal_emit_by_name (self->video_src, "run-javascript", script, NULL);
+}
+
 static void
 gst_wpe_src_set_location (GstWpeSrc * src, const gchar * location)
 {
@@ -542,6 +552,21 @@ gst_wpe_src_class_init (GstWpeSrcClass * klass)
       G_CALLBACK (gst_wpe_src_load_bytes), NULL, NULL, NULL, G_TYPE_NONE, 1,
       G_TYPE_BYTES);
 
+  /**
+   * GstWpeSrc::run-javascript:
+   * @src: the object which received the signal
+   * @script: the script to run
+   *
+   * Asynchronously run script in the context of the current page on the
+   * internal webView.
+   *
+   * Since: 1.22
+   */
+  gst_wpe_video_src_signals[SIGNAL_RUN_JAVASCRIPT] =
+      g_signal_new_class_handler ("run-javascript", G_TYPE_FROM_CLASS (klass),
+      static_cast < GSignalFlags > (G_SIGNAL_RUN_LAST | G_SIGNAL_ACTION),
+      G_CALLBACK (gst_wpe_src_run_javascript), NULL, NULL, NULL, G_TYPE_NONE, 1,
+      G_TYPE_STRING);
   element_class->change_state = GST_DEBUG_FUNCPTR (gst_wpe_src_change_state);
 
   gst_element_class_add_static_pad_template (element_class, &video_src_factory);

subprojects/gst-plugins-bad/ext/wpe/gstwpevideosrc.cpp

@@ -111,6 +111,7 @@ enum
 {
   SIGNAL_CONFIGURE_WEB_VIEW,
   SIGNAL_LOAD_BYTES,
+  SIGNAL_RUN_JAVASCRIPT,
   LAST_SIGNAL
 };
 static guint gst_wpe_video_src_signals[LAST_SIGNAL] = { 0 };
@@ -459,6 +460,15 @@ gst_wpe_video_src_configure_web_view (GstWpeVideoSrc * src,
   g_value_unset (&args[1]);
 }
 
+static void
+gst_wpe_video_src_run_javascript (GstWpeVideoSrc * src, const gchar * script)
+{
+  if (src->view && GST_STATE (GST_ELEMENT_CAST (src)) > GST_STATE_NULL) {
+    GST_INFO_OBJECT (src, "running javascript");
+    src->view->runJavascript (script);
+  }
+}
+
 static void
 gst_wpe_video_src_load_bytes (GstWpeVideoSrc * src, GBytes * bytes)
 {
@@ -879,4 +889,20 @@ gst_wpe_video_src_class_init (GstWpeVideoSrcClass * klass)
       static_cast < GSignalFlags > (G_SIGNAL_RUN_LAST | G_SIGNAL_ACTION),
       G_CALLBACK (gst_wpe_video_src_load_bytes), NULL, NULL, NULL,
       G_TYPE_NONE, 1, G_TYPE_BYTES);
+
+  /**
+   * GstWpeSrc::run-javascript:
+   * @src: the object which received the signal
+   * @script: the script to run
+   *
+   * Asynchronously run script in the context of the current page on the
+   * internal webView.
+   *
+   * Since: 1.22
+   */
+    gst_wpe_video_src_signals[SIGNAL_RUN_JAVASCRIPT] =
+      g_signal_new_class_handler ("run-javascript", G_TYPE_FROM_CLASS (klass),
+      static_cast < GSignalFlags > (G_SIGNAL_RUN_LAST | G_SIGNAL_ACTION),
+      G_CALLBACK (gst_wpe_video_src_run_javascript), NULL, NULL, NULL,
+      G_TYPE_NONE, 1, G_TYPE_STRING);
 }