[libcamera-devel] [PATCH v2 05/27] gst: Add pads to the source

[Nicolas Dufresne]

This simply adds the boiler plate for pads on the source element. The
design is that we have one pad, called "src", that will always be
present, and then more pads can be requested prior in READY or less
state. Initially pads have one property "stream-role" that let you
decide which role this pad will have.

Signed-off-by: Nicolas Dufresne <nicolas.dufresne at collabora.com>
---
 src/gstreamer/gstlibcamerapad.cpp | 101 ++++++++++++++++++++++++++++++
 src/gstreamer/gstlibcamerapad.h   |  19 ++++++
 src/gstreamer/gstlibcamerasrc.cpp |  19 ++++++
 src/gstreamer/meson.build         |   1 +
 4 files changed, 140 insertions(+)
 create mode 100644 src/gstreamer/gstlibcamerapad.cpp
 create mode 100644 src/gstreamer/gstlibcamerapad.h

diff --git a/src/gstreamer/gstlibcamerapad.cpp b/src/gstreamer/gstlibcamerapad.cpp
new file mode 100644
index 0000000..6212c3b
--- /dev/null
+++ b/src/gstreamer/gstlibcamerapad.cpp
@@ -0,0 +1,101 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2019, Collabora Ltd.
+ *     Author: Nicolas Dufresne <nicolas.dufresne at collabora.com>
+ *
+ * gstlibcamerapad.cpp - GStreamer Capture Pad
+ */
+
+#include "gstlibcamerapad.h"
+#include "gstlibcamera-utils.h"
+
+#include <libcamera/stream.h>
+
+using namespace libcamera;
+
+struct _GstLibcameraPad {
+	GstPad parent;
+	StreamRole role;
+};
+
+enum {
+	PROP_0,
+	PROP_STREAM_ROLE
+};
+
+G_DEFINE_TYPE(GstLibcameraPad, gst_libcamera_pad, GST_TYPE_PAD);
+
+static void
+gst_libcamera_pad_set_property(GObject *object, guint prop_id,
+			       const GValue *value, GParamSpec *pspec)
+{
+	auto *self = GST_LIBCAMERA_PAD(object);
+	GLibLocker lock(GST_OBJECT(self));
+
+	switch (prop_id) {
+	case PROP_STREAM_ROLE:
+		self->role = (StreamRole)g_value_get_enum(value);
+		break;
+	default:
+		G_OBJECT_WARN_INVALID_PROPERTY_ID(object, prop_id, pspec);
+		break;
+	}
+}
+
+static void
+gst_libcamera_pad_get_property(GObject *object, guint prop_id, GValue *value,
+			       GParamSpec *pspec)
+{
+	auto *self = GST_LIBCAMERA_PAD(object);
+	GLibLocker lock(GST_OBJECT(self));
+
+	switch (prop_id) {
+	case PROP_STREAM_ROLE:
+		g_value_set_enum(value, self->role);
+		break;
+	default:
+		G_OBJECT_WARN_INVALID_PROPERTY_ID(object, prop_id, pspec);
+		break;
+	}
+}
+
+static void
+gst_libcamera_pad_init(GstLibcameraPad *self)
+{
+}
+
+static GType
+gst_libcamera_stream_role_get_type(void)
+{
+	static GType type = 0;
+	static const GEnumValue values[] = {
+		{ StillCapture, "libcamera::StillCapture", "still-capture" },
+		{ VideoRecording, "libcamera::VideoRecording", "video-recording" },
+		{ Viewfinder, "libcamera::Viewfinder", "view-finder" },
+		{ 0, NULL, NULL }
+	};
+
+	if (!type)
+		type = g_enum_register_static("GstLibcameraStreamRole", values);
+
+	return type;
+}
+
+static void
+gst_libcamera_pad_class_init(GstLibcameraPadClass *klass)
+{
+	auto *object_class = G_OBJECT_CLASS(klass);
+
+	object_class->set_property = gst_libcamera_pad_set_property;
+	object_class->get_property = gst_libcamera_pad_get_property;
+
+	auto *spec = g_param_spec_enum("stream-role", "Stream Role",
+				       "The selected stream role",
+				       gst_libcamera_stream_role_get_type(),
+				       VideoRecording,
+				       (GParamFlags)(GST_PARAM_MUTABLE_READY
+					             | G_PARAM_CONSTRUCT
+						     | G_PARAM_READWRITE
+						     | G_PARAM_STATIC_STRINGS));
+	g_object_class_install_property(object_class, PROP_STREAM_ROLE, spec);
+}
diff --git a/src/gstreamer/gstlibcamerapad.h b/src/gstreamer/gstlibcamerapad.h
new file mode 100644
index 0000000..2e745f1
--- /dev/null
+++ b/src/gstreamer/gstlibcamerapad.h
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2019, Collabora Ltd.
+ *     Author: Nicolas Dufresne <nicolas.dufresne at collabora.com>
+ *
+ * gstlibcamerapad.h - GStreamer Capture Element
+ */
+
+#include <gst/gst.h>
+
+#ifndef __GST_LIBCAMERA_PAD_H__
+#define __GST_LIBCAMERA_PAD_H__
+
+#define GST_TYPE_LIBCAMERA_PAD gst_libcamera_pad_get_type()
+G_DECLARE_FINAL_TYPE(GstLibcameraPad, gst_libcamera_pad,
+		     GST_LIBCAMERA, PAD, GstPad)
+
+
+#endif /* __GST_LIBCAMERA_PAD_H__ */
diff --git a/src/gstreamer/gstlibcamerasrc.cpp b/src/gstreamer/gstlibcamerasrc.cpp
index 3807503..085c489 100644
--- a/src/gstreamer/gstlibcamerasrc.cpp
+++ b/src/gstreamer/gstlibcamerasrc.cpp
@@ -6,6 +6,7 @@
  * gstlibcamerasrc.cpp - GStreamer Capture Element
  */
 
+#include "gstlibcamerapad.h"
 #include "gstlibcamerasrc.h"
 
 struct _GstLibcameraSrc {
@@ -14,6 +15,18 @@ struct _GstLibcameraSrc {
 
 G_DEFINE_TYPE(GstLibcameraSrc, gst_libcamera_src, GST_TYPE_ELEMENT);
 
+#define TEMPLATE_CAPS GST_STATIC_CAPS("video/x-raw; image/jpeg")
+
+/* For the simple case, we have a src pad that is always present. */
+GstStaticPadTemplate src_template = {
+	"src", GST_PAD_SRC, GST_PAD_ALWAYS, TEMPLATE_CAPS
+};
+
+/* More pads can be requested in state < PAUSED */
+GstStaticPadTemplate request_src_template = {
+	"src_%s", GST_PAD_SRC, GST_PAD_REQUEST, TEMPLATE_CAPS
+};
+
 static void
 gst_libcamera_src_init(GstLibcameraSrc *self)
 {
@@ -28,4 +41,10 @@ gst_libcamera_src_class_init(GstLibcameraSrcClass *klass)
 				       "libcamera Source", "Source/Video",
 				       "Linux Camera source using libcamera",
 				       "Nicolas Dufresne <nicolas.dufresne at collabora.com");
+	gst_element_class_add_static_pad_template_with_gtype(element_class,
+							     &src_template,
+							     GST_TYPE_LIBCAMERA_PAD);
+	gst_element_class_add_static_pad_template_with_gtype(element_class,
+							     &request_src_template,
+							     GST_TYPE_LIBCAMERA_PAD);
 }
diff --git a/src/gstreamer/meson.build b/src/gstreamer/meson.build
index a57dd85..1c4a2e3 100644
--- a/src/gstreamer/meson.build
+++ b/src/gstreamer/meson.build
@@ -1,6 +1,7 @@
 libcamera_gst_sources = [
     'gstlibcamera-utils.cpp',
     'gstlibcamera.c',
+    'gstlibcamerapad.cpp',
     'gstlibcameraprovider.cpp',
     'gstlibcamerasrc.cpp',
 ]
-- 
2.24.1