Add comments, debug output, a bit of variable renaming and some code reorganization.

gst-sdk/tutorials/xcode iOS/Tutorial 2/GStreamerBackend.h

@@ -3,9 +3,14 @@
 
 @interface GStreamerBackend : NSObject
 
+/* Initialization method. Pass the delegate that will take care of the UI.
+ * This delegate must implement the GStreamerBackendDelegate protocol */
 -(id) init:(id) uiDelegate;
+
+/* Set the pipeline to PLAYING */
 -(void) play;
+
+/* Set the pipeline to PAUSED */
 -(void) pause;
--(void) stop;
 
 @end

gst-sdk/tutorials/xcode iOS/Tutorial 2/GStreamerBackend.m

@@ -2,6 +2,9 @@
 
 #include <gst/gst.h>
 
+GST_DEBUG_CATEGORY_STATIC (debug_category);
+#define GST_CAT_DEFAULT debug_category
+
 @interface GStreamerBackend()
 -(void)setUIMessage:(gchar*) message;
 -(void)app_function;
@@ -9,18 +12,25 @@
 @end
 
 @implementation GStreamerBackend {
-    id delegate;           /* Class that we use to interact with the user interface */
+    id ui_delegate;        /* Class that we use to interact with the user interface */
     GstElement *pipeline;  /* The running pipeline */
     GMainContext *context; /* GLib context used to run the main loop */
     GMainLoop *main_loop;  /* GLib main loop */
     gboolean initialized;  /* To avoid informing the UI multiple times about the initialization */
 }
 
+/*
+ * Interface methods
+ */
+
 -(id) init:(id) uiDelegate
 {
     if (self = [super init])
     {
-        self->delegate = uiDelegate;
+        self->ui_delegate = uiDelegate;
+
+        GST_DEBUG_CATEGORY_INIT (debug_category, "tutorial-2", 0, "iOS tutorial 2");
+        gst_debug_set_threshold_for_name("tutorial-2", GST_LEVEL_DEBUG);
 
         /* Start the bus monitoring task */
         dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
@@ -34,18 +44,38 @@
 -(void) dealloc
 {
     if (pipeline) {
+        GST_DEBUG("Setting the pipeline to NULL");
         gst_element_set_state(pipeline, GST_STATE_NULL);
         gst_object_unref(pipeline);
         pipeline = NULL;
     }
 }
 
+-(void) play
+{
+    if(gst_element_set_state(pipeline, GST_STATE_PLAYING) == GST_STATE_CHANGE_FAILURE) {
+        [self setUIMessage:"Failed to set pipeline to playing"];
+    }
+}
+
+-(void) pause
+{
+    if(gst_element_set_state(pipeline, GST_STATE_PAUSED) == GST_STATE_CHANGE_FAILURE) {
+        [self setUIMessage:"Failed to set pipeline to paused"];
+    }
+}
+
+/*
+ * Private methods
+ */
+
+/* Change the message on the UI through the UI delegate */
 -(void)setUIMessage:(gchar*) message
 {
     NSString *string = [NSString stringWithUTF8String:message];
-    if(delegate && [delegate respondsToSelector:@selector(gstreamerSetUIMessage:)])
+    if(ui_delegate && [ui_delegate respondsToSelector:@selector(gstreamerSetUIMessage:)])
     {
-        [delegate gstreamerSetUIMessage:string];
+        [ui_delegate gstreamerSetUIMessage:string];
     }
 }
 
@@ -84,15 +114,15 @@ static void state_changed_cb (GstBus *bus, GstMessage *msg, GStreamerBackend *se
 {
     if (!initialized && main_loop) {
         GST_DEBUG ("Initialization complete, notifying application.");
-        if (delegate && [delegate respondsToSelector:@selector(gstreamerInitialized)])
+        if (ui_delegate && [ui_delegate respondsToSelector:@selector(gstreamerInitialized)])
         {
-            [delegate gstreamerInitialized];
+            [ui_delegate gstreamerInitialized];
         }
         initialized = TRUE;
     }
 }
 
-/* Main method for the native code. This is executed on its own thread. */
+/* Main method for the bus monitoring code */
 -(void) app_function
 {
     GstBus *bus;
@@ -143,25 +173,5 @@ static void state_changed_cb (GstBus *bus, GstMessage *msg, GStreamerBackend *se
     return;
 }
 
--(void) play
-{
-    if(gst_element_set_state(pipeline, GST_STATE_PLAYING) == GST_STATE_CHANGE_FAILURE) {
-        [self setUIMessage:"Failed to set pipeline to playing"];
-    }
-}
-
--(void) pause
-{
-    if(gst_element_set_state(pipeline, GST_STATE_PAUSED) == GST_STATE_CHANGE_FAILURE) {
-        [self setUIMessage:"Failed to set pipeline to paused"];
-    }
-}
-
--(void) stop
-{
-    if(pipeline)
-        gst_element_set_state(pipeline, GST_STATE_NULL);
-}
-
 @end
 

gst-sdk/tutorials/xcode iOS/Tutorial 2/GStreamerBackendDelegate.h

@@ -3,7 +3,12 @@
 @protocol GStreamerBackendDelegate <NSObject>
 
 @optional
+/* Called when the GStreamer backend has finished initializing
+ * and is ready to accept orders. */
 -(void) gstreamerInitialized;
+
+/* Called when the GStreamer backend wants to output some message
+ * to the screen. */
 -(void) gstreamerSetUIMessage:(NSString *)message;
 
 @end

gst-sdk/tutorials/xcode iOS/Tutorial 2/ViewController.m

@@ -10,6 +10,10 @@
 
 @implementation ViewController
 
+/*
+ * Methods from UIViewController
+ */
+
 - (void)viewDidLoad
 {
     [super viewDidLoad];
@@ -26,16 +30,22 @@
     // Dispose of any resources that can be recreated.
 }
 
+/* Called when the Play button is pressed */
 -(IBAction) play:(id)sender
 {
     [gst_backend play];
 }
 
+/* Called when the Pause button is pressed */
 -(IBAction) pause:(id)sender
 {
     [gst_backend pause];
 }
 
+/*
+ * Methods from GstreamerBackendDelegate
+ */
+
 -(void) gstreamerInitialized
 {
     dispatch_async(dispatch_get_main_queue(), ^{