giostreamsink: Add a property to close stream on stop()

Back in the mists of time[1], we switched `giostream*` elements to not close the
stream on stop() so that applications that needed a handle to the stream after
the element stopped had it.

Unfortunately, we also have cases[2] where waiting for the element to be
finalized is too late for the stream to be closed.

In order to not change the behaviour of the element, we add a property to allow
users to select the desired behaviour.

[1]: https://bugzilla.gnome.org/show_bug.cgi?id=587896
[2]: gst-plugins-rs#423

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/5372>

subprojects/gst-plugins-base/docs/plugins/gst_plugins_cache.json

@@ -2811,7 +2811,21 @@
                     "GInitiallyUnowned",
                     "GObject"
                 ],
-                "kind": "object"
+                "kind": "object",
+                "properties": {
+                    "close-on-stop": {
+                        "blurb": "Close the stream when the element stops (i.e. goes from READY to NULL) rather than when the element is disposed)",
+                        "conditionally-available": false,
+                        "construct": false,
+                        "construct-only": false,
+                        "controllable": false,
+                        "default": "true",
+                        "mutable": "null",
+                        "readable": true,
+                        "type": "gboolean",
+                        "writable": true
+                    }
+                }
             },
             "GstGioBaseSrc": {
                 "hierarchy": [

subprojects/gst-plugins-base/gst/gio/gstgiobasesink.c

@@ -29,6 +29,14 @@
 GST_DEBUG_CATEGORY_STATIC (gst_gio_base_sink_debug);
 #define GST_CAT_DEFAULT gst_gio_base_sink_debug
 
+#define DEFAULT_CLOSE_ON_STOP FALSE
+
+enum
+{
+  PROP_0,
+  PROP_CLOSE_ON_STOP,
+};
+
 static GstStaticPadTemplate sink_factory = GST_STATIC_PAD_TEMPLATE ("sink",
     GST_PAD_SINK,
     GST_PAD_ALWAYS,
@@ -38,6 +46,10 @@ static GstStaticPadTemplate sink_factory = GST_STATIC_PAD_TEMPLATE ("sink",
 G_DEFINE_TYPE (GstGioBaseSink, gst_gio_base_sink, GST_TYPE_BASE_SINK);
 
 static void gst_gio_base_sink_finalize (GObject * object);
+static void gst_gio_base_sink_get_property (GObject * object, guint prop_id,
+    GValue * value, GParamSpec * pspec);
+static void gst_gio_base_sink_set_property (GObject * object, guint prop_id,
+    const GValue * value, GParamSpec * pspec);
 static gboolean gst_gio_base_sink_start (GstBaseSink * base_sink);
 static gboolean gst_gio_base_sink_stop (GstBaseSink * base_sink);
 static gboolean gst_gio_base_sink_unlock (GstBaseSink * base_sink);
@@ -59,9 +71,27 @@ gst_gio_base_sink_class_init (GstGioBaseSinkClass * klass)
       "GIO base sink");
 
   gobject_class->finalize = gst_gio_base_sink_finalize;
+  gobject_class->get_property = gst_gio_base_sink_get_property;
+  gobject_class->set_property = gst_gio_base_sink_set_property;
 
   gst_element_class_add_static_pad_template (gstelement_class, &sink_factory);
 
+  /**
+   * GstGioBaseSink:close-on-stop:
+   *
+   * Determines whether the stream is closed with the element "stops" (i.e. goes
+   * from the READY to NULL state), or when the element is disposed. Which of
+   * these behaviours is desirable depends on the lifecycle of the underlying
+   * stream that the element works with.
+   *
+   * Since: 1.24
+   */
+  g_object_class_install_property (gobject_class, PROP_CLOSE_ON_STOP,
+      g_param_spec_boolean ("close-on-stop", "Close stream on stop",
+          "Close the stream when the element stops (i.e. goes from READY to "
+          "NULL) rather than when the element is disposed)",
+          DEFAULT_CLOSE_ON_STOP, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
+
   gstbasesink_class->start = GST_DEBUG_FUNCPTR (gst_gio_base_sink_start);
   gstbasesink_class->stop = GST_DEBUG_FUNCPTR (gst_gio_base_sink_stop);
   gstbasesink_class->unlock = GST_DEBUG_FUNCPTR (gst_gio_base_sink_unlock);
@@ -80,6 +110,8 @@ gst_gio_base_sink_init (GstGioBaseSink * sink)
   gst_base_sink_set_sync (GST_BASE_SINK (sink), FALSE);
 
   sink->cancel = g_cancellable_new ();
+  // FALSE is the historical default for this class
+  sink->close_on_stop = DEFAULT_CLOSE_ON_STOP;
 }
 
 static void
@@ -100,6 +132,38 @@ gst_gio_base_sink_finalize (GObject * object)
   GST_CALL_PARENT (G_OBJECT_CLASS, finalize, (object));
 }
 
+static void
+gst_gio_base_sink_get_property (GObject * object, guint prop_id,
+    GValue * value, GParamSpec * pspec)
+{
+  GstGioBaseSink *sink = GST_GIO_BASE_SINK (object);
+
+  switch (prop_id) {
+    case PROP_CLOSE_ON_STOP:
+      g_value_set_boolean (value, sink->close_on_stop);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
+
+static void
+gst_gio_base_sink_set_property (GObject * object, guint prop_id,
+    const GValue * value, GParamSpec * pspec)
+{
+  GstGioBaseSink *sink = GST_GIO_BASE_SINK (object);
+
+  switch (prop_id) {
+    case PROP_CLOSE_ON_STOP:
+      sink->close_on_stop = g_value_get_boolean (value);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
+
 static gboolean
 gst_gio_base_sink_start (GstBaseSink * base_sink)
 {
@@ -129,11 +193,10 @@ static gboolean
 gst_gio_base_sink_stop (GstBaseSink * base_sink)
 {
   GstGioBaseSink *sink = GST_GIO_BASE_SINK (base_sink);
-  GstGioBaseSinkClass *klass = GST_GIO_BASE_SINK_GET_CLASS (sink);
   gboolean success;
   GError *err = NULL;
 
-  if (klass->close_on_stop && G_IS_OUTPUT_STREAM (sink->stream)) {
+  if (sink->close_on_stop && G_IS_OUTPUT_STREAM (sink->stream)) {
     GST_DEBUG_OBJECT (sink, "closing stream");
 
     /* FIXME: can block but unfortunately we can't use async operations

subprojects/gst-plugins-base/gst/gio/gstgiobasesink.h

@@ -55,6 +55,7 @@ struct _GstGioBaseSink
 
   /* < private > */
   GOutputStream *stream;
+  gboolean close_on_stop;
 };
 
 struct _GstGioBaseSinkClass 
@@ -62,7 +63,6 @@ struct _GstGioBaseSinkClass
   GstBaseSinkClass parent_class;
 
   GOutputStream * (*get_stream) (GstGioBaseSink *bsink);
-  gboolean close_on_stop;
 };
 
 GType gst_gio_base_sink_get_type (void);

subprojects/gst-plugins-base/gst/gio/gstgiosink.c

@@ -144,12 +144,15 @@ gst_gio_sink_class_init (GstGioSinkClass * klass)
 
   gstgiobasesink_class->get_stream =
       GST_DEBUG_FUNCPTR (gst_gio_sink_get_stream);
-  gstgiobasesink_class->close_on_stop = TRUE;
 }
 
 static void
 gst_gio_sink_init (GstGioSink * sink)
 {
+  GstGioBaseSink *bsink = GST_GIO_BASE_SINK (sink);
+
+  // TRUE is the historical default for this element
+  bsink->close_on_stop = TRUE;
 }
 
 static void