[gstreamermm] Gst::CapsFeatures: improve construction methods

[Marcin Kolny <mkolny src gnome org>]

commit 49b4652de040fb437881ea8087e3bddfe08efb2e
Author: Marcin Kolny <marcin kolny gmail com>
Date:   Thu Aug 27 17:39:30 2015 +0000

    Gst::CapsFeatures: improve construction methods
    
        * gstreamer/src/capsfeatures.{ccg|hg}: wrap create_any() and
          create_from_string() using _WRAP_METHOD macro, use
          std::initializer_list in constructor. Also comment for
          Gst::CapsFeatures class has been added.
        * gstreamer/src/gst_extra_object.defs: add CapsFeatures to
          extra-objects list.
        * tests/test-capsfeatures.cc: build fix test.
        * tools/m4/convert_gst.m4: add conversion definition
          (GstCapsFeatures* -> Gst::CapsFeatures).

 gstreamer/src/capsfeatures.ccg       |   25 +++++----------
 gstreamer/src/capsfeatures.hg        |   55 +++++++++++++++++++++------------
 gstreamer/src/gst_extra_objects.defs |    6 ++++
 tests/test-capsfeatures.cc           |    2 +-
 tools/m4/convert_gst.m4              |    1 +
 5 files changed, 51 insertions(+), 38 deletions(-)
---
diff --git a/gstreamer/src/capsfeatures.ccg b/gstreamer/src/capsfeatures.ccg
index b79193f..d3df7cc 100644
--- a/gstreamer/src/capsfeatures.ccg
+++ b/gstreamer/src/capsfeatures.ccg
@@ -21,27 +21,18 @@
 
 namespace Gst
 {
-
-CapsFeatures::CapsFeatures()
+CapsFeatures::CapsFeatures(std::initializer_list<Glib::ustring> features)
+ : CapsFeatures()
 {
-  gobject_ =  gst_caps_features_new_empty();
+  for (auto feature : features)
+  {
+    gst_caps_features_add(gobject_, feature.c_str());
+  }
 }
 
-CapsFeatures::CapsFeatures(const Glib::ustring& feature1)
+Glib::ustring CapsFeatures::memory_system_memory()
 {
-  gobject_ =  gst_caps_features_new(feature1.c_str(), nullptr);
+  return GST_CAPS_FEATURE_MEMORY_SYSTEM_MEMORY;
 }
 
-CapsFeatures CapsFeatures::create_any()
-{
-  return CapsFeatures(gst_caps_features_new_any(), false);
-}
-
-
-CapsFeatures CapsFeatures::create_from_string(const Glib::ustring& features)
-{
-  return CapsFeatures(gst_caps_features_from_string(features.c_str()), false);
-}
-
-
 }
diff --git a/gstreamer/src/capsfeatures.hg b/gstreamer/src/capsfeatures.hg
index 279c4dc..aea72dc 100644
--- a/gstreamer/src/capsfeatures.hg
+++ b/gstreamer/src/capsfeatures.hg
@@ -24,41 +24,52 @@ _DEFS(gstreamermm,gst)
 namespace Gst
 {
 
+/**
+ * A set of features in caps
+ *
+ * Gst::CapsFeatures can optionally be set on a Gst::Caps to add requirements
+ * for additional features for a specific Gst::Structure. Caps structures with
+ * the same name but with a non-equal set of caps features are not compatible.
+ * If a pad supports multiple sets of features it has to add multiple equal
+ * structures with different feature sets to the caps.
+ *
+ * Empty Gst::CapsFeatures are equivalent with the Gst::CapsFeatures that only
+ * contain Gst::CapsFeatures::memory_system_memory(). ANY Gst::CapsFeatures as
+ * created by Gst::CapsFeatures::create_any() are equal to any other Gst::CapsFeatures
+ * and can be used to specify that any Gst::CapsFeatures would be supported, e.g.
+ * for elements that don't touch buffer memory. Gst::Caps with ANY Gst::CapsFeatures
+ * are considered non-fixed and during negotiation some Gst::CapsFeatures have
+ * to be selected.
+ *
+ * Examples for caps features would be the requirement of a specific Gst::Memory
+ * types or the requirement of having a specific Gst::Meta on the buffer. Features
+ * are given as a string of the format "memory:GstMemoryTypeName" or
+ * "meta:GstMetaAPIName".
+ *
+ * Since: 1.2
+ */
 class CapsFeatures
 {
-  _CLASS_BOXEDTYPE(CapsFeatures, GstCapsFeatures, NONE, gst_caps_features_copy, gst_caps_features_free)
+  _CLASS_BOXEDTYPE(CapsFeatures, GstCapsFeatures, gst_caps_features_new_empty, gst_caps_features_copy, 
gst_caps_features_free)
 
 
   _IGNORE(gst_caps_features_new_id_valist)
   _IGNORE(gst_caps_features_new_valist)
+  _IGNORE(gst_caps_features_new_empty)
   _IGNORE(gst_caps_features_copy)
   _IGNORE(gst_caps_features_free)
 
 public:
-  _CUSTOM_DEFAULT_CTOR
-
   /**
-   * Creates a new, empty Gst::CapsFeatures.
-   */
-  CapsFeatures();
-  _IGNORE(gst_caps_features_new_empty)
-
-  /**
-   * Creates a new Gst::CapsFeatures with the given first feature.
+   * Creates a new Gst::CapsFeatures with the given features.
    *
-   * @param feature1 name of first feature to set.
+   * @param features name of features to set.
    */
-  explicit CapsFeatures(const Glib::ustring& feature1);
+  explicit CapsFeatures(std::initializer_list<Glib::ustring> features);
 
-  /**
-   * Creates a new, ANY Gst::CapsFeatures. This will be equal to any other
-   * Gst::CapsFeatures but caps with these are unfixed.
-   */
-  static CapsFeatures create_any();
-  _IGNORE(gst_caps_features_new_any)
+  _WRAP_METHOD(static Gst::CapsFeatures create_any(), gst_caps_features_new_any)
 
-  static CapsFeatures create_from_string(const Glib::ustring& features);
-  _IGNORE(gst_caps_features_from_string)
+  _WRAP_METHOD(static Gst::CapsFeatures create_from_string(const Glib::ustring& features), 
gst_caps_features_from_string)
 
   _WRAP_METHOD(Glib::ustring to_string() const, gst_caps_features_to_string)
 
@@ -85,6 +96,10 @@ public:
   _WRAP_METHOD(void remove(const Glib::ustring& feature), gst_caps_features_remove)
 
   _WRAP_METHOD(void remove(GQuark feature), gst_caps_features_remove_id)
+
+  /** Constant for system memory feature name.
+   */
+  static Glib::ustring memory_system_memory();
 };
 
 }
diff --git a/gstreamer/src/gst_extra_objects.defs b/gstreamer/src/gst_extra_objects.defs
index 8a32fec..667c35c 100644
--- a/gstreamer/src/gst_extra_objects.defs
+++ b/gstreamer/src/gst_extra_objects.defs
@@ -29,6 +29,12 @@
   (gtype-id "GST_TYPE_CAPS")
 )
 
+(define-object CapsFeatures
+  (in-module "Gst")
+  (c-name "GstCapsFeatures")
+  (gtype-id "GST_TYPE_CAPS_FEATURES")
+)
+
 (define-object Iterator
   (in-module "Gst")
   (c-name "GstIterator")
diff --git a/tests/test-capsfeatures.cc b/tests/test-capsfeatures.cc
index ac8af40..12b7d69 100644
--- a/tests/test-capsfeatures.cc
+++ b/tests/test-capsfeatures.cc
@@ -18,7 +18,7 @@ TEST(CapsFeaturesTest, ShouldCorrectCreateEmptyFeature)
 
 TEST(CapsFeaturesTest, AddRemoveFeaturesShouldWorkProperly)
 {
-  CapsFeatures features (GST_CAPS_FEATURE_MEMORY_SYSTEM_MEMORY);
+  CapsFeatures features {GST_CAPS_FEATURE_MEMORY_SYSTEM_MEMORY};
   ASSERT_EQ(1u, features.get_size());
   ASSERT_STREQ(GST_CAPS_FEATURE_MEMORY_SYSTEM_MEMORY, features.get_nth(0).c_str());
   features.remove(GST_CAPS_FEATURE_MEMORY_SYSTEM_MEMORY);
diff --git a/tools/m4/convert_gst.m4 b/tools/m4/convert_gst.m4
index 175a524..c0530a3 100644
--- a/tools/m4/convert_gst.m4
+++ b/tools/m4/convert_gst.m4
@@ -123,6 +123,7 @@ _CONVERSION(`Glib::RefPtr<Gst::Caps>&&',`GstCaps*',`($3) ? $3.release()->gobj()
 
 dnl CapsFeatures
 _CONVERSION(`const Gst::CapsFeatures&',`const GstCapsFeatures*',`$3.gobj()')
+_CONVERSION(`GstCapsFeatures*',`Gst::CapsFeatures',`CapsFeatures($3, false)')
 
 dnl Clock
 _CONVERSION(`GstClock*',`Glib::RefPtr<Gst::Clock>',`Glib::wrap($3)')