[libcamera-devel] [PATCH v3 4/6] libcamera: camera: extend camera object to support streams

[Niklas Söderlund]

A camera consist of one or more video streams origination from the same
video source. The different streams could for example have access to
different hardware blocks in the video pipeline and therefor be able to
process the video source in different ways.

All static information describing each streams needs to be recorded at
camera creation. After a camera is created an application can retrieve
the static information about its stream at any time.

Update all pipeline handlers to register one stream per camera, this
might be extended in the future for some of the pipelines.

Signed-off-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>
---
 include/libcamera/camera.h           | 10 ++++-
 src/libcamera/camera.cpp             | 55 ++++++++++++++++++++++++++--
 src/libcamera/pipeline/ipu3/ipu3.cpp |  4 +-
 src/libcamera/pipeline/uvcvideo.cpp  |  4 +-
 src/libcamera/pipeline/vimc.cpp      |  4 +-
 5 files changed, 69 insertions(+), 8 deletions(-)

diff --git a/include/libcamera/camera.h b/include/libcamera/camera.h
index 7e358f8c0aa093cf..786d4d7d66bed5b2 100644
--- a/include/libcamera/camera.h
+++ b/include/libcamera/camera.h
@@ -15,12 +15,14 @@
 namespace libcamera {
 
 class PipelineHandler;
+class Stream;
 
 class Camera final
 {
 public:
 	static std::shared_ptr<Camera> create(PipelineHandler *pipe,
-					      const std::string &name);
+					      const std::string &name,
+					      const std::vector<Stream> &streams);
 
 	Camera(const Camera &) = delete;
 	void operator=(const Camera &) = delete;
@@ -32,6 +34,8 @@ public:
 	int acquire();
 	void release();
 
+	std::vector<Stream> streams() const;
+
 private:
 	Camera(PipelineHandler *pipe, const std::string &name);
 	~Camera();
@@ -39,10 +43,14 @@ private:
 	friend class PipelineHandler;
 	void disconnect();
 
+	bool haveStreamID(unsigned int id) const;
+
 	std::shared_ptr<PipelineHandler> pipe_;
 	std::string name_;
+	std::vector<Stream> streams_;
 
 	bool acquired_;
+	bool disconnected_;
 };
 
 } /* namespace libcamera */
diff --git a/src/libcamera/camera.cpp b/src/libcamera/camera.cpp
index 500976b237bcbd2d..3b2c00d0a4bb45d1 100644
--- a/src/libcamera/camera.cpp
+++ b/src/libcamera/camera.cpp
@@ -6,6 +6,7 @@
  */
 
 #include <libcamera/camera.h>
+#include <libcamera/stream.h>
 
 #include "log.h"
 #include "pipeline_handler.h"
@@ -56,13 +57,15 @@ LOG_DECLARE_CATEGORY(Camera)
  * \brief Create a camera instance
  * \param[in] name The name of the camera device
  * \param[in] pipe The pipeline handler responsible for the camera device
+ * \param[in] streams Array of streams the camera shall provide
  *
  * The caller is responsible for guaranteeing unicity of the camera name.
  *
  * \return A shared pointer to the newly created camera object
  */
 std::shared_ptr<Camera> Camera::create(PipelineHandler *pipe,
-				       const std::string &name)
+				       const std::string &name,
+				       const std::vector<Stream> &streams)
 {
 	struct Allocator : std::allocator<Camera> {
 		void construct(void *p, PipelineHandler *pipe,
@@ -76,7 +79,19 @@ std::shared_ptr<Camera> Camera::create(PipelineHandler *pipe,
 		}
 	};
 
-	return std::allocate_shared<Camera>(Allocator(), pipe, name);
+	std::shared_ptr<Camera> camera =
+		std::allocate_shared<Camera>(Allocator(), pipe, name);
+
+	for (const Stream &stream : streams) {
+		if (camera->haveStreamID(stream.id())) {
+			LOG(Camera, Error) << "Duplication of stream ID";
+			camera.reset();
+			break;
+		}
+		camera->streams_.push_back(stream);
+	}
+
+	return camera;
 }
 
 /**
@@ -102,7 +117,8 @@ const std::string &Camera::name() const
  */
 
 Camera::Camera(PipelineHandler *pipe, const std::string &name)
-	: pipe_(pipe->shared_from_this()), name_(name), acquired_(false)
+	: pipe_(pipe->shared_from_this()), name_(name), acquired_(false),
+	  disconnected_(false)
 {
 }
 
@@ -125,10 +141,24 @@ void Camera::disconnect()
 {
 	LOG(Camera, Debug) << "Disconnecting camera " << name_;
 
-	/** \todo Block API calls when they will be implemented. */
+	disconnected_ = true;
 	disconnected.emit(this);
 }
 
+/**
+ * \brief Check if camera have a stream ID
+ * \param[in] id Stream ID to check for
+ * \return ture if stream ID exists, else false
+ */
+bool Camera::haveStreamID(unsigned int id) const
+{
+	for (const Stream &stream : streams_)
+		if (stream.id() == id)
+			return true;
+
+	return false;
+}
+
 /**
  * \brief Acquire the camera device for exclusive access
  *
@@ -164,4 +194,21 @@ void Camera::release()
 	acquired_ = false;
 }
 
+/**
+ * \brief Retrieve all the camera's stream information
+ *
+ * Retrieve all of the camera's static stream information. The static
+ * information describes among other things how many streams the camera support
+ * and each streams capabilities.
+ *
+ * \return An array of all the camera's streams or an empty list on error.
+ */
+std::vector<Stream> Camera::streams() const
+{
+	if (disconnected_)
+		return std::vector<Stream>{};
+
+	return streams_;
+}
+
 } /* namespace libcamera */
diff --git a/src/libcamera/pipeline/ipu3/ipu3.cpp b/src/libcamera/pipeline/ipu3/ipu3.cpp
index d74655d037728feb..dbb2a89163c36cbc 100644
--- a/src/libcamera/pipeline/ipu3/ipu3.cpp
+++ b/src/libcamera/pipeline/ipu3/ipu3.cpp
@@ -9,6 +9,7 @@
 #include <vector>
 
 #include <libcamera/camera.h>
+#include <libcamera/stream.h>
 
 #include "device_enumerator.h"
 #include "log.h"
@@ -197,7 +198,8 @@ void PipelineHandlerIPU3::registerCameras()
 			continue;
 
 		std::string cameraName = sensor->name() + " " + std::to_string(id);
-		std::shared_ptr<Camera> camera = Camera::create(this, cameraName);
+		std::vector<Stream> streams{ Stream(0) };
+		std::shared_ptr<Camera> camera = Camera::create(this, cameraName, streams);
 
 		/*
 		 * If V4L2 device creation fails, the Camera instance won't be
diff --git a/src/libcamera/pipeline/uvcvideo.cpp b/src/libcamera/pipeline/uvcvideo.cpp
index c51e8bc1f2c2bf25..bc4a8d7236be589d 100644
--- a/src/libcamera/pipeline/uvcvideo.cpp
+++ b/src/libcamera/pipeline/uvcvideo.cpp
@@ -6,6 +6,7 @@
  */
 
 #include <libcamera/camera.h>
+#include <libcamera/stream.h>
 
 #include "device_enumerator.h"
 #include "media_device.h"
@@ -64,7 +65,8 @@ bool PipelineHandlerUVC::match(DeviceEnumerator *enumerator)
 		return false;
 	}
 
-	std::shared_ptr<Camera> camera = Camera::create(this, media_->model());
+	std::vector<Stream> streams{ Stream(0) };
+	std::shared_ptr<Camera> camera = Camera::create(this, media_->model(), streams);
 	registerCamera(std::move(camera));
 	hotplugMediaDevice(media_.get());
 
diff --git a/src/libcamera/pipeline/vimc.cpp b/src/libcamera/pipeline/vimc.cpp
index f58a97d51619515d..c426a953aea1b3dd 100644
--- a/src/libcamera/pipeline/vimc.cpp
+++ b/src/libcamera/pipeline/vimc.cpp
@@ -6,6 +6,7 @@
  */
 
 #include <libcamera/camera.h>
+#include <libcamera/stream.h>
 
 #include "device_enumerator.h"
 #include "media_device.h"
@@ -56,7 +57,8 @@ bool PipeHandlerVimc::match(DeviceEnumerator *enumerator)
 
 	media_->acquire();
 
-	std::shared_ptr<Camera> camera = Camera::create(this, "Dummy VIMC Camera");
+	std::vector<Stream> streams{ Stream(0) };
+	std::shared_ptr<Camera> camera = Camera::create(this, "Dummy VIMC Camera", streams);
 	registerCamera(std::move(camera));
 
 	return true;
-- 
2.20.1