qt_avplay: avoid deprecated Xml_node methods

Besides replacing deprecated API calls, this patch also adds the 'base'
library to the target's LIBS (which is mandated by the change of issue
genodelabs/genode#3758) and changes the URL of the example mediafile
to a working one.

Issue genodelabs/genode#3755

run/qt5_avplay.run

@@ -23,7 +23,7 @@ build $build_components
 # Download media file
 #
 
-set media_url "ftp://ftp.untergrund.net/users/ae/dhstv/escape-chotro.mp4"
+set media_url "http://os.inf.tu-dresden.de/~nf2/povray/blob.mpg"
 if {![file exists bin/mediafile]} {
 	puts "downloading media file from $media_url"
 	catch { exec wget -O bin/mediafile $media_url }

src/app/qt_avplay/main.cpp

@@ -33,14 +33,12 @@ static inline void load_stylesheet()
         qApp->setStyleSheet(QLatin1String(file.readAll()));
 }
 
-extern void initialize_qt_core(Genode::Env &);
 extern void initialize_qt_gui(Genode::Env &);
 
 void Libc::Component::construct(Libc::Env &env)
 {
 	Libc::with_libc([&] {
 
-		initialize_qt_core(env);
 		initialize_qt_gui(env);
 
 		int argc = 1;

src/app/qt_avplay/main_window.cpp

@@ -42,7 +42,7 @@ Main_window::Main_window(Genode::Env &env)
 
 	Avplay_slave *avplay_slave = new Avplay_slave(_env, _ep,
 	                                              _nitpicker_service,
-	                                              _mediafile_name.buf);
+	                                              _mediafile_name.name.string());
 
 	connect(_control_bar, SIGNAL(volume_changed(int)), avplay_slave, SLOT(volume_changed(int)));
 }

src/app/qt_avplay/main_window.h

@@ -43,21 +43,29 @@ class Main_window : public Compound_widget<QWidget, QVBoxLayout>
 
 		struct Mediafile_name
 		{
-			/* get the name of the media file from the config file */
-			enum { MAX_LEN_MEDIAFILE_NAME = 256 };
-			char buf[MAX_LEN_MEDIAFILE_NAME];
+			typedef Genode::String<256> Name;
+			Name const name;
 
-			Mediafile_name(Genode::Env &env)
+			Name _name_from_config(Genode::Env &env)
 			{
-				Genode::strncpy(buf, "mediafile", sizeof(buf));
-				try {
-					Genode::Attached_rom_dataspace config(env, "config");
-					config.xml().sub_node("mediafile")
-						.attribute("name").value(buf, sizeof(buf));
-				} catch(...) {
-					Genode::warning("no <mediafile> config node found, using \"mediafile\"");
-				}
+				using namespace Genode;
+
+				Attached_rom_dataspace config_ds(env, "config");
+				Xml_node const config = config_ds.xml();
+				char const * const node_type = "mediafile";
+
+				if (!config.has_sub_node(node_type))
+					warning("no <", node_type, " name=\"...\"> config node found, "
+					        "using \"mediafile\"");
+
+				Name result { "mediafile" };
+				config.with_sub_node(node_type, [&] (Xml_node const &mediafile) {
+					result = mediafile.attribute_value("name", result); });
+
+				return result;
 			}
+
+			Mediafile_name(Genode::Env &env) : name(_name_from_config(env)) { }
 		};
 
 		Genode::Env                   &_env;

src/app/qt_avplay/target.mk

@@ -2,7 +2,7 @@ include $(call select_from_repositories,src/app/qt5/tmpl/target_defaults.inc)
 
 include $(call select_from_repositories,src/app/qt5/tmpl/target_final.inc)
 
-LIBS += qt5_qnitpickerviewwidget qoost
+LIBS += qt5_qnitpickerviewwidget qoost base
 
 REP_INC_DIR += include/qt5/qpa_nitpicker