[libcamera-devel] [PATCH 1/2] libcamera: Add a PipelineHandler::releaseDevice method

[David Plowman]

This notifies pipeline handlers when a camera is released, in case
they want to free any resources or memory buffers.

Signed-off-by: David Plowman <david.plowman at raspberrypi.com>
---
 include/libcamera/internal/pipeline_handler.h |  4 +++-
 src/libcamera/camera.cpp                      |  2 +-
 src/libcamera/pipeline_handler.cpp            | 16 +++++++++++++++-
 3 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/include/libcamera/internal/pipeline_handler.h b/include/libcamera/internal/pipeline_handler.h
index 96aab9d6..ec4f662d 100644
--- a/include/libcamera/internal/pipeline_handler.h
+++ b/include/libcamera/internal/pipeline_handler.h
@@ -46,7 +46,7 @@ public:
 					const DeviceMatch &dm);
 
 	bool acquire();
-	void release();
+	void release(Camera *camera);
 
 	virtual std::unique_ptr<CameraConfiguration> generateConfiguration(Camera *camera,
 		const StreamRoles &roles) = 0;
@@ -74,6 +74,8 @@ protected:
 	virtual int queueRequestDevice(Camera *camera, Request *request) = 0;
 	virtual void stopDevice(Camera *camera) = 0;
 
+	virtual void releaseDevice(Camera *camera);
+
 	CameraManager *manager_;
 
 private:
diff --git a/src/libcamera/camera.cpp b/src/libcamera/camera.cpp
index c4f65c1a..2d947a44 100644
--- a/src/libcamera/camera.cpp
+++ b/src/libcamera/camera.cpp
@@ -870,7 +870,7 @@ int Camera::release()
 		return ret == -EACCES ? -EBUSY : ret;
 
 	if (d->isAcquired())
-		d->pipe_->release();
+		d->pipe_->release(this);
 
 	d->setState(Private::CameraAvailable);
 
diff --git a/src/libcamera/pipeline_handler.cpp b/src/libcamera/pipeline_handler.cpp
index 825aff5a..cfade490 100644
--- a/src/libcamera/pipeline_handler.cpp
+++ b/src/libcamera/pipeline_handler.cpp
@@ -183,6 +183,7 @@ bool PipelineHandler::acquire()
 
 /**
  * \brief Release exclusive access to the pipeline handler
+ * \param[in] camera The camera for which to release data
  *
  * This function releases access to the pipeline handler previously acquired by
  * a call to acquire(). Every release() call shall match a previous successful
@@ -196,7 +197,7 @@ bool PipelineHandler::acquire()
  *
  * \sa acquire()
  */
-void PipelineHandler::release()
+void PipelineHandler::release(Camera *camera)
 {
 	MutexLocker locker(lock_);
 
@@ -204,9 +205,22 @@ void PipelineHandler::release()
 
 	unlockMediaDevices();
 
+	releaseDevice(camera);
+
 	--useCount_;
 }
 
+/**
+ * \brief Release resources associated with this camera
+ * \param[in] camera The camera for which to release resources
+ *
+ * Pipeline handlers may override this in order to perform cleanup operations
+ * when a camera is released, such as freeing memory.
+ */
+void PipelineHandler::releaseDevice([[maybe_unused]] Camera *camera)
+{
+}
+
 void PipelineHandler::unlockMediaDevices()
 {
 	for (std::shared_ptr<MediaDevice> &media : mediaDevices_)
-- 
2.30.2