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/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
* Copyright (C) 2018, Google Inc.
*
* camera_manager.h - Camera management
*/
#include <libcamera/camera.h>
#include <libcamera/camera_manager.h>
#include <libcamera/event_dispatcher.h>
#include "device_enumerator.h"
#include "event_dispatcher_poll.h"
#include "log.h"
#include "pipeline_handler.h"
#include "utils.h"
/**
* \file camera_manager.h
* \brief The camera manager
*/
namespace libcamera {
LOG_DEFINE_CATEGORY(Camera)
/**
* \class CameraManager
* \brief Provide access and manage all cameras in the system
*
* The camera manager is the entry point to libcamera. It enumerates devices,
* associates them with pipeline managers, and provides access to the cameras
* in the system to applications. The manager owns all Camera objects and
* handles hot-plugging and hot-unplugging to manage the lifetime of cameras.
*
* To interact with libcamera, an application retrieves the camera manager
* instance with CameraManager::instance(). The manager is initially stopped,
* and shall be configured before being started. In particular a custom event
* dispatcher shall be installed if needed with
* CameraManager::setEventDispatcher().
*
* Once the camera manager is configured, it shall be started with start().
* This will enumerate all the cameras present in the system, which can then be
* listed with list() and retrieved with get().
*
* 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.
*
* \todo Add interface to register a notification callback to the user to be
* able to inform it new cameras have been hot-plugged or cameras have been
* removed due to hot-unplug.
*/
CameraManager::CameraManager()
: enumerator_(nullptr), dispatcher_(nullptr)
{
}
CameraManager::~CameraManager()
{
}
/**
* \brief Start the camera manager
*
* Start the camera manager and enumerate all devices in the system. Once
* the start has been confirmed the user is free to list and otherwise
* interact with cameras in the system until either the camera manager
* is stopped or the camera is unplugged from the system.
*
* \return 0 on successful start, or a negative error code otherwise
*/
int CameraManager::start()
{
if (enumerator_)
return -EBUSY;
enumerator_ = DeviceEnumerator::create();
if (enumerator_->enumerate())
return -ENODEV;
/*
* TODO: Try to read handlers and order from configuration
* file and only fallback on all handlers if there is no
* configuration file.
*/
std::vector<PipelineHandlerFactory *> &factories = PipelineHandlerFactory::factories();
for (PipelineHandlerFactory *factory : factories) {
/*
* Try each pipeline handler until it exhaust
* all pipelines it can provide.
*/
while (1) {
PipelineHandler *pipe = factory->create();
if (!pipe->match(this, enumerator_.get())) {
delete pipe;
break;
}
LOG(Camera, Debug)
<< "Pipeline handler \"" << factory->name()
<< "\" matched";
pipes_.push_back(pipe);
}
}
/* TODO: register hot-plug callback here */
return 0;
}
/**
* \brief Stop the camera manager
*
* Before stopping the camera manager the caller is responsible for making
* sure all cameras provided by the manager are returned to the manager.
*
* After the manager has been stopped no resource provided by the camera
* manager should be consider valid or functional even if they for one
* reason or another have yet to be deleted.
*/
void CameraManager::stop()
{
/* TODO: unregister hot-plug callback here */
for (PipelineHandler *pipe : pipes_)
delete pipe;
pipes_.clear();
enumerator_.reset(nullptr);
}
/**
* \fn CameraManager::cameras()
* \brief Retrieve all available cameras
*
* Before calling this function the caller is responsible for ensuring that
* the camera manger is running.
*
* \return List of all available cameras
*/
/**
* \brief Get a camera based on name
*
* \param[in] name Name of camera to get
*
* Before calling this function the caller is responsible for ensuring that
* the camera manger is running.
*
* \return Shared pointer to Camera object or nullptr if camera not found
*/
std::shared_ptr<Camera> CameraManager::get(const std::string &name)
{
for (std::shared_ptr<Camera> camera : cameras_) {
if (camera->name() == name)
return camera;
}
return nullptr;
}
/**
* \brief Add a camera to the camera manager
* \param[in] camera The camera to be added
*
* This function is called by pipeline handlers to register the cameras they
* handle with the camera manager. Registered cameras are immediately made
* available to the system.
*/
void CameraManager::addCamera(std::shared_ptr<Camera> camera)
{
for (std::shared_ptr<Camera> c : cameras_) {
if (c->name() == camera->name()) {
LOG(Camera, Warning)
<< "Registering camera with duplicate name '"
<< camera->name() << "'";
break;
}
}
cameras_.push_back(std::move(camera));
}
/**
* \brief Retrieve the camera manager instance
*
* The CameraManager is a singleton and can't be constructed manually. This
* function shall instead be used to retrieve the single global instance of the
* manager.
*
* \return The camera manager instance
*/
CameraManager *CameraManager::instance()
{
static CameraManager manager;
return &manager;
}
/**
* \brief Set the event dispatcher
* \param dispatcher Pointer to the event dispatcher
*
* libcamera requires an event dispatcher to integrate event notification and
* timers with the application event loop. Applications that want to provide
* their own event dispatcher shall call this function once and only once before
* the camera manager is started with start(). If no event dispatcher is
* provided, a default poll-based implementation will be used.
*
* The CameraManager takes ownership of the event dispatcher and will delete it
* when the application terminates.
*/
void CameraManager::setEventDispatcher(std::unique_ptr<EventDispatcher> dispatcher)
{
if (dispatcher_) {
LOG(Camera, Warning) << "Event dispatcher is already set";
return;
}
dispatcher_ = std::move(dispatcher);
}
/**
* \brief Retrieve the event dispatcher
*
* This function retrieves the event dispatcher set with setEventDispatcher().
* If no dispatcher has been set, a default poll-based implementation is created
* and returned, and no custom event dispatcher may be installed anymore.
*
* The returned event dispatcher is valid until the camera manager is destroyed.
*
* \return Pointer to the event dispatcher
*/
EventDispatcher *CameraManager::eventDispatcher()
{
if (!dispatcher_)
dispatcher_ = utils::make_unique<EventDispatcherPoll>();
return dispatcher_.get();
}
} /* namespace libcamera */
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