@@ -7,22 +7,25 @@
#ifndef __LIBCAMERA_CAMERA_H__
#define __LIBCAMERA_CAMERA_H__
+#include <memory>
#include <string>
namespace libcamera {
-class Camera
+class Camera final
{
public:
- Camera(const std::string &name);
+ static std::shared_ptr<Camera> create(const std::string &name);
+
+ Camera(const Camera &) = delete;
+ void operator=(const Camera &) = delete;
const std::string &name() const;
- void get();
- void put();
private:
- virtual ~Camera() { };
- int ref_;
+ explicit Camera(const std::string &name);
+ ~Camera();
+
std::string name_;
};
@@ -24,10 +24,10 @@ public:
int start();
void stop();
- const std::vector<Camera *> &cameras() const { return cameras_; }
- Camera *get(const std::string &name);
+ const std::vector<std::shared_ptr<Camera>> &cameras() const { return cameras_; }
+ std::shared_ptr<Camera> get(const std::string &name);
- void addCamera(Camera *camera);
+ void addCamera(std::shared_ptr<Camera> camera);
static CameraManager *instance();
@@ -42,7 +42,7 @@ private:
std::unique_ptr<DeviceEnumerator> enumerator_;
std::vector<PipelineHandler *> pipes_;
- std::vector<Camera *> cameras_;
+ std::vector<std::shared_ptr<Camera>> cameras_;
std::unique_ptr<EventDispatcher> dispatcher_;
};
@@ -41,19 +41,36 @@ namespace libcamera {
* streams from a single image source. It provides the main interface to
* configuring and controlling the device, and capturing image streams. It is
* the central object exposed by libcamera.
+ *
+ * To support the central nature of Camera objects, libcamera manages the
+ * lifetime of camera instances with std::shared_ptr<>. Instances shall be
+ * created with the create() function which returns a shared pointer. The
+ * Camera constructors and destructor are private, to prevent instances from
+ * being constructed and destroyed manually.
*/
/**
- * \brief Construct a named camera device
+ * \brief Create a camera instance
+ * \param[in] name The name of the camera device
*
- * \param[in] name The name to set on the camera device
+ * The caller is responsible for guaranteeing unicity of the camera name.
*
- * The caller is responsible for guaranteeing unicity of the camera
- * device name.
+ * \return A shared pointer to the newly created camera object
*/
-Camera::Camera(const std::string &name)
- : ref_(1), name_(name)
+std::shared_ptr<Camera> Camera::create(const std::string &name)
{
+ struct Allocator : std::allocator<Camera> {
+ void construct(void *p, const std::string &name)
+ {
+ ::new(p) Camera(name);
+ }
+ void destroy(Camera *p)
+ {
+ p->~Camera();
+ }
+ };
+
+ return std::allocate_shared<Camera>(Allocator(), name);
}
/**
@@ -66,24 +83,13 @@ const std::string &Camera::name() const
return name_;
}
-/**
- * \brief Acquire a reference to the camera
- */
-void Camera::get()
+Camera::Camera(const std::string &name)
+ : name_(name)
{
- ref_++;
}
-/**
- * \brief Release a reference to the camera
- *
- * When the last reference is released the camera device is deleted. Callers
- * shall not access the camera device after calling this function.
- */
-void Camera::put()
+Camera::~Camera()
{
- if (--ref_ == 0)
- delete this;
}
} /* namespace libcamera */
@@ -40,9 +40,11 @@ namespace libcamera {
* This will enumerate all the cameras present in the system, which can then be
* listed with list() and retrieved with get().
*
- * Cameras are reference-counted, and shall be returned to the camera manager
- * with Camera::put() after being used. Once all cameras have been returned to
- * the manager, it can be stopped with stop().
+ * Cameras are shared through std::shared_ptr<>, ensuring that a camera will
+ * stay valid until the last reference is released without requiring any special
+ * action from the application. Once the application has released all the
+ * references it held to cameras, the camera manager can be stopped with
+ * stop().
*
* \todo Add ability to add and remove media devices based on hot-(un)plug
* events coming from the device enumerator.
@@ -148,15 +150,13 @@ void CameraManager::stop()
* \param[in] name Name of camera to get
*
* Before calling this function the caller is responsible for ensuring that
- * the camera manger is running. A camera fetched this way shall be
- * released by the user with the put() method of the Camera object once
- * it is done using the camera.
+ * the camera manger is running.
*
- * \return Pointer to Camera object or nullptr if camera not found
+ * \return Shared pointer to Camera object or nullptr if camera not found
*/
-Camera *CameraManager::get(const std::string &name)
+std::shared_ptr<Camera> CameraManager::get(const std::string &name)
{
- for (Camera *camera : cameras_) {
+ for (std::shared_ptr<Camera> camera : cameras_) {
if (camera->name() == name)
return camera;
}
@@ -172,9 +172,9 @@ Camera *CameraManager::get(const std::string &name)
* handle with the camera manager. Registered cameras are immediately made
* available to the system.
*/
-void CameraManager::addCamera(Camera *camera)
+void CameraManager::addCamera(std::shared_ptr<Camera> camera)
{
- for (Camera *c : cameras_) {
+ for (std::shared_ptr<Camera> c : cameras_) {
if (c->name() == camera->name()) {
LOG(Warning) << "Registering camera with duplicate name '"
<< camera->name() << "'";
@@ -182,7 +182,7 @@ void CameraManager::addCamera(Camera *camera)
}
}
- cameras_.push_back(camera);
+ cameras_.push_back(std::move(camera));
}
/**
@@ -64,8 +64,8 @@ bool PipeHandlerVimc::match(CameraManager *manager, DeviceEnumerator *enumerator
* will be chosen depends on how the Camera
* object is modeled.
*/
- Camera *camera = new Camera("Dummy VIMC Camera");
- manager->addCamera(camera);
+ std::shared_ptr<Camera> camera = Camera::create("Dummy VIMC Camera");
+ manager->addCamera(std::move(camera));
return true;
}
@@ -30,7 +30,7 @@ protected:
{
unsigned int count = 0;
- for (Camera *camera : cm->cameras()) {
+ for (const std::shared_ptr<Camera> &camera : cm->cameras()) {
cout << "- " << camera->name() << endl;
count++;
}