Creation of the base class StreamSource. It is intended to become the

base class for all gstreamer pipeline. DeviceSource and PatternSource
inherit from it. A generic stream source class is created for
development tests and hack.

StreamSource.h

@@ -0,0 +1,73 @@
+#ifndef STREAMSOURCE_H
+#define STREAMSOURCE_H
+
+
+#include "Stream.h"
+#include "Source.h"
+
+/**
+ * @brief The StreamSource class
+ *
+ * StreamSource is a virtual base class
+ * (because stream() = 0)
+ * based on the virtual base class Source
+ * that implements the update and display
+ * of a Stream object (gstreamer generic)
+ *
+ * StreamSource does *not* create a stream
+ * in its constructor to let this for the
+ * specific implementation of the subclass.
+ * Therefore it cannot be instanciated and
+ * it cannot give access to its stream.
+ *
+ */
+class StreamSource: public Source
+{
+public:
+    StreamSource();
+    virtual ~StreamSource();
+
+    // implementation of source API
+    void update (float dt) override;
+    void setActive (bool on) override;
+    void render() override;
+    bool failed() const override;
+    uint texture() const override;
+
+    // pure virtual interface
+    virtual Stream *stream() const = 0;
+
+protected:
+    void init() override;
+    void replaceRenderingShader() override;
+
+    Surface *surface_;
+    Stream *stream_;
+};
+
+/**
+ * @brief The GenericStreamSource class
+ *
+ * Implements the StreamSource
+ * with an initialization
+ * using a generic description
+ * of the gstreamer pipeline.
+ *
+ * It can be instanciated.
+ */
+class GenericStreamSource : public StreamSource
+{
+public:
+    GenericStreamSource();
+
+    // Source interface
+    void accept (Visitor& v) override;
+
+    // StreamSource interface
+    Stream *stream() const override { return stream_; }
+
+    // specific interface
+    void setDescription(const std::string &desc);
+};
+
+#endif // STREAMSOURCE_H