lib: Add video_source_type enumeration

Add an enum to struct video_source that details the type of source
we're dealing with. This will be used to make decisions about buffer
allocation and handling in a more explicit way.

Use the video_source_type associated with a video_source to decide on
the appropriate allocation function and buffer handler at stream on time.
This is a more explicit method than relying on the presence of the
.alloc_buffers op and allows more flexibility.

Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: Daniel Scally <dan.scally@ideasonboard.com>

7 files changed, 30 insertions, 6 deletions

diff --git a/include/uvcgadget/video-source.h b/include/uvcgadget/video-source.h
index b1a3cf4..f888ce4 100644
--- a/include/uvcgadget/video-source.h
+++ b/include/uvcgadget/video-source.h
@@ -32,11 +32,24 @@ struct video_source_ops {
 typedef void(*video_source_buffer_handler_t)(void *, struct video_source *,
 					     struct video_buffer *);
 
+/*
+ * video_source_type - Enumeration of the different kinds of video source
+ * @VIDEO_SOURCE_DMABUF		A source that can share data with the sink via a
+ *				DMA file descriptor.
+ * @VIDEO_SOURCE_STATIC		A source that draws data from an unchanging
+ *				buffer such as a .jpg file
+ */
+enum video_source_type {
+	VIDEO_SOURCE_DMABUF,
+	VIDEO_SOURCE_STATIC,
+};
+
 struct video_source {
 	const struct video_source_ops *ops;
 	struct events *events;
 	video_source_buffer_handler_t handler;
 	void *handler_data;
+	enum video_source_type type;
 };
 
 void video_source_set_buffer_handler(struct video_source *src,
diff --git a/lib/jpg-source.c b/lib/jpg-source.c
index c95d76c..1cc0052 100644
--- a/lib/jpg-source.c
+++ b/lib/jpg-source.c
@@ -149,6 +149,7 @@ struct video_source *jpg_video_source_create(const char *img_path)
 
 	memset(src, 0, sizeof *src);
 	src->src.ops = &jpg_source_ops;
+	src->src.type = VIDEO_SOURCE_STATIC;
 
 	fd = open(img_path, O_RDONLY);
 	if (fd == -1) {
diff --git a/lib/libcamera-source.cpp b/lib/libcamera-source.cpp
index c53c915..7b4e212 100644
--- a/lib/libcamera-source.cpp
+++ b/lib/libcamera-source.cpp
@@ -390,6 +390,7 @@ struct video_source *libcamera_source_create(const char *devname)
 	}
 
 	src->src.ops = &libcamera_source_ops;
+	src->src.type = VIDEO_SOURCE_DMABUF;
 	src->cm = std::make_unique<CameraManager>();
 	src->cm->start();
 
diff --git a/lib/slideshow-source.c b/lib/slideshow-source.c
index 42a42a9..6eeab72 100644
--- a/lib/slideshow-source.c
+++ b/lib/slideshow-source.c
@@ -367,6 +367,7 @@ struct video_source *slideshow_video_source_create(const char *img_dir)
 
 	memset(src, 0, sizeof *src);
 	src->src.ops = &slideshow_source_ops;
+	src->src.type = VIDEO_SOURCE_STATIC;
 
 	strncpy(src->img_dir, img_dir, sizeof(src->img_dir));
 
diff --git a/lib/stream.c b/lib/stream.c
index 63ccb1b..4a562a5 100644
--- a/lib/stream.c
+++ b/lib/stream.c
@@ -7,6 +7,7 @@
  * Contact: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
  */
 
+#include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -183,10 +184,19 @@ static int uvc_stream_start(struct uvc_stream *stream)
 {
 	printf("Starting video stream.\n");
 
-	if (stream->src->ops->alloc_buffers)
+	switch (stream->src->type) {
+	case VIDEO_SOURCE_DMABUF:
+		video_source_set_buffer_handler(stream->src, uvc_stream_source_process,
+						stream);
 		return uvc_stream_start_alloc(stream);
-	else
+	case VIDEO_SOURCE_STATIC:
 		return uvc_stream_start_no_alloc(stream);
+	default:
+		fprintf(stderr, "invalid video source type\n");
+		break;
+	}
+
+	return -EINVAL;
 }
 
 static int uvc_stream_stop(struct uvc_stream *stream)
@@ -288,8 +298,4 @@ void uvc_stream_set_video_source(struct uvc_stream *stream,
 				 struct video_source *src)
 {
 	stream->src = src;
-
-	if (stream->src->ops->alloc_buffers)
-		video_source_set_buffer_handler(src, uvc_stream_source_process,
-						stream);
 }
diff --git a/lib/test-source.c b/lib/test-source.c
index 743d8b3..40a1f69 100644
--- a/lib/test-source.c
+++ b/lib/test-source.c
@@ -134,6 +134,7 @@ struct video_source *test_video_source_create()
 
 	memset(src, 0, sizeof *src);
 	src->src.ops = &test_source_ops;
+	src->src.type = VIDEO_SOURCE_STATIC;
 
 	return &src->src;
 }
diff --git a/lib/v4l2-source.c b/lib/v4l2-source.c
index 8cb9aef..22fe3da 100644
--- a/lib/v4l2-source.c
+++ b/lib/v4l2-source.c
@@ -170,6 +170,7 @@ struct video_source *v4l2_video_source_create(const char *devname)
 
 	memset(src, 0, sizeof *src);
 	src->src.ops = &v4l2_source_ops;
+	src->src.type = VIDEO_SOURCE_DMABUF;
 
 	src->vdev = v4l2_open(devname);
 	if (!src->vdev) {