GStreamer: add createFromPipelineDescription

Helper functions to run `gst_parse_launch` and friends.

Pick-to: 6.5 6.7
Change-Id: Iaa45fe97778ebea82cde155f925b309fa8ec8561
Reviewed-by: Jøger Hansegård <joger.hansegard@qt.io>
Reviewed-by: Artem Dyomin <artem.dyomin@qt.io>

4 files changed, 113 insertions, 1 deletions

diff --git a/src/plugins/multimedia/gstreamer/common/qgst.cpp b/src/plugins/multimedia/gstreamer/common/qgst.cpp
index 8a77533a6..6f1a291a1 100644
--- a/src/plugins/multimedia/gstreamer/common/qgst.cpp
+++ b/src/plugins/multimedia/gstreamer/common/qgst.cpp
@@ -656,6 +656,11 @@ GType QGstObject::type() const
     return G_OBJECT_TYPE(get());
 }
 
+const char *QGstObject::typeName() const
+{
+    return g_type_name(type());
+}
+
 GstObject *QGstObject::object() const
 {
     return get();
@@ -858,6 +863,25 @@ QGstElement QGstElement::createFromDevice(GstDevice *device, const char *name)
     };
 }
 
+QGstElement QGstElement::createFromPipelineDescription(const char *str)
+{
+    QUniqueGErrorHandle error;
+    QGstElement element{
+        gst_parse_launch(str, &error),
+        QGstElement::NeedsRef,
+    };
+
+    if (error) // error does not mean that the element could not be constructed
+        qWarning() << "gst_parse_launch error:" << error;
+
+    return element;
+}
+
+QGstElement QGstElement::createFromPipelineDescription(const QByteArray &str)
+{
+    return createFromPipelineDescription(str.constData());
+}
+
 QGstPad QGstElement::staticPad(const char *name) const
 {
     return QGstPad(gst_element_get_static_pad(element(), name), HasRef);
@@ -1016,6 +1040,36 @@ QGstBin QGstBin::createFromFactory(const char *factory, const char *name)
     };
 }
 
+QGstBin QGstBin::createFromPipelineDescription(const QByteArray &pipelineDescription,
+                                               const char *name, bool ghostUnlinkedPads)
+{
+    return createFromPipelineDescription(pipelineDescription.constData(), name, ghostUnlinkedPads);
+}
+
+QGstBin QGstBin::createFromPipelineDescription(const char *pipelineDescription, const char *name,
+                                               bool ghostUnlinkedPads)
+{
+    QUniqueGErrorHandle error;
+
+    GstElement *element =
+            gst_parse_bin_from_description_full(pipelineDescription, ghostUnlinkedPads,
+                                                /*context=*/nullptr, GST_PARSE_FLAG_NONE, &error);
+
+    if (!element) {
+        qWarning() << "Failed to make element from pipeline description" << pipelineDescription
+                   << error;
+        return QGstBin{};
+    }
+
+    if (name)
+        gst_element_set_name(element, name);
+
+    return QGstBin{
+        element,
+        NeedsRef,
+    };
+}
+
 QGstBin::QGstBin(GstBin *bin, RefMode mode)
     : QGstElement{
           qGstCheckedCast<GstElement>(bin),
diff --git a/src/plugins/multimedia/gstreamer/common/qgst_p.h b/src/plugins/multimedia/gstreamer/common/qgst_p.h
index ec41b508d..34b7e7e22 100644
--- a/src/plugins/multimedia/gstreamer/common/qgst_p.h
+++ b/src/plugins/multimedia/gstreamer/common/qgst_p.h
@@ -408,6 +408,7 @@ public:
     void disconnect(gulong handlerId);
 
     GType type() const;
+    const char *typeName() const;
     GstObject *object() const;
     const char *name() const;
 };
@@ -558,6 +559,8 @@ public:
                                          const char *name = nullptr);
     static QGstElement createFromDevice(const QGstDeviceHandle &, const char *name = nullptr);
     static QGstElement createFromDevice(GstDevice *, const char *name = nullptr);
+    static QGstElement createFromPipelineDescription(const char *);
+    static QGstElement createFromPipelineDescription(const QByteArray &);
 
     QGstPad staticPad(const char *name) const;
     QGstPad src() const;
@@ -669,6 +672,12 @@ public:
     explicit QGstBin(GstBin *bin, RefMode mode = NeedsRef);
     static QGstBin create(const char *name);
     static QGstBin createFromFactory(const char *factory, const char *name);
+    static QGstBin createFromPipelineDescription(const QByteArray &pipelineDescription,
+                                                 const char *name = nullptr,
+                                                 bool ghostUnlinkedPads = false);
+    static QGstBin createFromPipelineDescription(const char *pipelineDescription,
+                                                 const char *name = nullptr,
+                                                 bool ghostUnlinkedPads = false);
 
     template <typename... Ts>
     std::enable_if_t<(std::is_base_of_v<QGstElement, Ts> && ...), void> add(const Ts &...ts)
diff --git a/tests/auto/unit/multimedia/gstreamer_backend/tst_gstreamer_backend.cpp b/tests/auto/unit/multimedia/gstreamer_backend/tst_gstreamer_backend.cpp
index b0d814dfd..763ff01bf 100644
--- a/tests/auto/unit/multimedia/gstreamer_backend/tst_gstreamer_backend.cpp
+++ b/tests/auto/unit/multimedia/gstreamer_backend/tst_gstreamer_backend.cpp
@@ -4,8 +4,10 @@
 #include "tst_gstreamer_backend.h"
 
 #include <QtTest/QtTest>
-#include <QtQGstreamerMediaPlugin/private/qgstreamermetadata_p.h>
+
 #include <QtQGstreamerMediaPlugin/private/qgst_handle_types_p.h>
+#include <QtQGstreamerMediaPlugin/private/qgst_p.h>
+#include <QtQGstreamerMediaPlugin/private/qgstreamermetadata_p.h>
 
 QT_USE_NAMESPACE
 
@@ -73,6 +75,49 @@ void tst_GStreamer::metadata_taglistToMetaData_extractsDuration()
     QCOMPARE(parsed[QMediaMetaData::Duration].value<int>(), 400);
 }
 
+void tst_GStreamer::QGstBin_createFromPipelineDescription()
+{
+    QGstBin bin = QGstBin::createFromPipelineDescription("identity name=foo ! identity name=bar");
+
+    QVERIFY(bin);
+    QVERIFY(bin.findByName("foo"));
+    QCOMPARE_EQ(bin.findByName("foo").getParent(), bin);
+    QVERIFY(bin.findByName("bar"));
+    QVERIFY(!bin.findByName("baz"));
+    bin.dumpGraph("QGstBin_createFromPipelineDescription");
+}
+
+void tst_GStreamer::QGstElement_createFromPipelineDescription()
+{
+    using namespace std::string_view_literals;
+    QGstElement element = QGstElement::createFromPipelineDescription("identity name=foo");
+    QCOMPARE_EQ(element.name(), "foo"sv);
+    QCOMPARE_EQ(element.typeName(), "GstIdentity"sv);
+}
+
+void tst_GStreamer::QGstElement_createFromPipelineDescription_multipleElementsCreatesBin()
+{
+    using namespace std::string_view_literals;
+    QGstElement element =
+            QGstElement::createFromPipelineDescription("identity name=foo ! identity name=bar");
+
+    QVERIFY(element);
+    QCOMPARE_EQ(element.typeName(), "GstPipeline"sv);
+
+    QGstBin bin{
+        qGstSafeCast<GstBin>(element.element()),
+        QGstBin::NeedsRef,
+    };
+
+    QVERIFY(bin);
+    QVERIFY(bin.findByName("foo"));
+    QCOMPARE_EQ(bin.findByName("foo").getParent(), bin);
+    QVERIFY(bin.findByName("bar"));
+    QVERIFY(!bin.findByName("baz"));
+
+    bin.dumpGraph("QGstElement_createFromPipelineDescription_multipleElements");
+}
+
 QTEST_GUILESS_MAIN(tst_GStreamer)
 
 #include "moc_tst_gstreamer_backend.cpp"
diff --git a/tests/auto/unit/multimedia/gstreamer_backend/tst_gstreamer_backend.h b/tests/auto/unit/multimedia/gstreamer_backend/tst_gstreamer_backend.h
index e84e3f7cd..0a1628031 100644
--- a/tests/auto/unit/multimedia/gstreamer_backend/tst_gstreamer_backend.h
+++ b/tests/auto/unit/multimedia/gstreamer_backend/tst_gstreamer_backend.h
@@ -24,6 +24,10 @@ private slots:
     void metadata_taglistToMetaData_extractsOrientation_data();
     void metadata_taglistToMetaData_extractsDuration();
 
+    void QGstBin_createFromPipelineDescription();
+    void QGstElement_createFromPipelineDescription();
+    void QGstElement_createFromPipelineDescription_multipleElementsCreatesBin();
+
 private:
     QGstreamerIntegration integration;
 };