allocator: add gst_allocation_params_new()

This permits creating GstAllocationParams instances on the heap, which
is useful for language bindings that can handle GBoxed types.

https://gitlab.freedesktop.org/gstreamer/gstreamer/-/issues/683

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/788>

gst/gstallocator.c

@@ -142,6 +142,31 @@ G_DEFINE_BOXED_TYPE (GstAllocationParams, gst_allocation_params,
     (GBoxedCopyFunc) gst_allocation_params_copy,
     (GBoxedFreeFunc) gst_allocation_params_free);
 
+/**
+ * gst_allocation_params_new:
+ *
+ * Create a new #GstAllocationParams on the heap.  This function is for
+ * use in GStreamer language bindings.  In your own code, you can just
+ * declare a #GstAllocationParams on the stack or in a struct, and
+ * call gst_allocation_params_init() to initialize it.
+ *
+ * You do not need to call gst_allocation_params_init() on the instance
+ * returned by this function.
+ *
+ * Returns: (transfer full) (not nullable): a new #GstAllocationParams
+ *
+ * Since: 1.20
+ */
+GstAllocationParams *
+gst_allocation_params_new (void)
+{
+  /* Call new() and then init(), rather than calling new0(), in case
+   * init() ever changes to something other than a memset(). */
+  GstAllocationParams *result = g_slice_new (GstAllocationParams);
+  gst_allocation_params_init (result);
+  return result;
+}
+
 /**
  * gst_allocation_params_init:
  * @params: a #GstAllocationParams

gst/gstallocator.h

@@ -167,6 +167,9 @@ void           gst_allocator_set_default     (GstAllocator * allocator);
 
 /* allocation parameters */
 
+GST_API
+GstAllocationParams * gst_allocation_params_new (void) G_GNUC_MALLOC;
+
 GST_API
 void           gst_allocation_params_init    (GstAllocationParams *params);