[{"id":3293,"web_url":"https://patchwork.libcamera.org/comment/3293/","msgid":"<20200102004635.GC15498@pendragon.ideasonboard.com>","date":"2020-01-02T00:46:35","subject":"Re: [libcamera-devel] [PATCH v4 2/4] libcamera: camera_manager,\n\tpipeline_handler: allow retrieving cameras by device numbers","submitter":{"id":2,"url":"https://patchwork.libcamera.org/api/people/2/","name":"Laurent Pinchart","email":"laurent.pinchart@ideasonboard.com"},"content":"Hi Paul,\n\nThank you for the patch.\n\nOn Mon, Dec 30, 2019 at 11:33:12PM -0600, Paul Elder wrote:\n> The V4L2 compatibility layer will need a way to map device numbers to\n> libcamera Camera instances. Expose a method in the camera manager to\n> retrieve Camera instances by devnum. The mapping from device numbers to\n> Camera instances is optionally declared by pipeline handlers when they\n> register cameras with the camera manager.\n> \n> Signed-off-by: Paul Elder \n> Reviewed-by: Jacopo Mondi \n> \n> ---\n> Changes in v4:\n> - squashed 4/6 from v3\n> - simplified registering devnum -> camera mappings\n> - old (v3) system: pipeline handlers have their own map, that camera\n> manager aggregates\n> - new (v4) system: pipeline handlers, when they register the camera\n> with the camera manager, (optionally) declare the devnum along with it\n> \n> New in v3\n> ---\n> include/libcamera/camera_manager.h | 5 +++-\n> src/libcamera/camera_manager.cpp | 37 +++++++++++++++++++++++-\n> src/libcamera/include/pipeline_handler.h | 3 +-\n> src/libcamera/pipeline_handler.cpp | 13 +++++++--\n> 4 files changed, 53 insertions(+), 5 deletions(-)\n> \n> diff --git a/include/libcamera/camera_manager.h b/include/libcamera/camera_manager.h\n> index 8331898c..d2d6e443 100644\n> --- a/include/libcamera/camera_manager.h\n> +++ b/include/libcamera/camera_manager.h\n> @@ -7,6 +7,7 @@\n> #ifndef __LIBCAMERA_CAMERA_MANAGER_H__\n> #define __LIBCAMERA_CAMERA_MANAGER_H__\n> \n> +#include \n> #include \n> #include \n\nShould you include for dev_t ?\n\n> #include \n> @@ -33,8 +34,9 @@ public:\n> \n> \tconst std::vector> &cameras() const { return cameras_; }\n> \tstd::shared_ptr get(const std::string &name);\n> +\tstd::shared_ptr get(dev_t devnum);\n> \n> -\tvoid addCamera(std::shared_ptr camera);\n> +\tvoid addCamera(std::shared_ptr camera, dev_t devnum);\n> \tvoid removeCamera(Camera *camera);\n> \n> \tstatic const std::string &version() { return version_; }\n> @@ -46,6 +48,7 @@ private:\n> \tstd::unique_ptr enumerator_;\n> \tstd::vector> pipes_;\n> \tstd::vector> cameras_;\n> +\tstd::map> camerasByDevnum_;\n> \n> \tstatic const std::string version_;\n> \tstatic CameraManager *self_;\n> diff --git a/src/libcamera/camera_manager.cpp b/src/libcamera/camera_manager.cpp\n> index 7c6f72bb..b6204872 100644\n> --- a/src/libcamera/camera_manager.cpp\n> +++ b/src/libcamera/camera_manager.cpp\n> @@ -180,15 +180,45 @@ std::shared_ptr CameraManager::get(const std::string &name)\n> \treturn nullptr;\n> }\n> \n> +/**\n> + * \\brief Retrieve a camera based on device number\n> + * \\param[in] devnum Device number of camera to get\n> + *\n> + * Retrieving a camera based on device number is done by the V4L2 compatibility\n> + * layer to map device nodes to libcamera Camera instances.\n> + *\n> + * Regular applications are recommended to retrieve libcamera Camera instances\n> + * by name instead.\n\nI'd make this a stronger requirement:\n\n * This method is meant solely for the use of the V4L2 compatibility\n * layer, to map device nodes to Camera instances. Applications shall\n * not use it and shall instead retrieve cameras by name.\n\n> + *\n> + * Before calling this function the caller is responsible for ensuring that\n> + * the camera manager is running.\n> + *\n> + * \\return Shared pointer to Camera object, which is empty if the camera is\n> + * not found\n> + */\n> +std::shared_ptr CameraManager::get(dev_t devnum)\n> +{\n> +\tauto iter = camerasByDevnum_.find(devnum);\n> +\n\nI think you can drop this blank line.\n\n> +\tif (iter == camerasByDevnum_.end())\n> +\t\treturn nullptr;\n> +\n> +\treturn iter->second.lock();\n> +}\n> +\n> /**\n> * \\brief Add a camera to the camera manager\n> * \\param[in] camera The camera to be added\n> + * \\param[in] devnum The device number to associate with \\a camera\n> *\n> * This function is called by pipeline handlers to register the cameras they\n> * handle with the camera manager. Registered cameras are immediately made\n> * available to the system.\n> + *\n> + * \\a devnum is used by the V4L2 compatibility layer to map V4L2 device nodes\n> + * to libcamera Camera instances.\n\ns/libcamera // as we're in libcamera, so this is the default :-)\n\n> */\n> -void CameraManager::addCamera(std::shared_ptr camera)\n> +void CameraManager::addCamera(std::shared_ptr camera, dev_t devnum)\n> {\n> \tfor (std::shared_ptr c : cameras_) {\n> \t\tif (c->name() == camera->name()) {\n> @@ -200,6 +230,11 @@ void CameraManager::addCamera(std::shared_ptr camera)\n> \t}\n> \n> \tcameras_.push_back(std::move(camera));\n> +\n> +\tif (devnum) {\n> +\t\tunsigned int index = cameras_.size() - 1;\n> +\t\tcamerasByDevnum_[devnum] = cameras_[index];\n> +\t}\n> }\n\nYou also need to update CameraManager::removeCamera.\n\ndiff --git a/src/libcamera/camera_manager.cpp b/src/libcamera/camera_manager.cpp\nindex 7c6f72bbe120..d45d81effa8d 100644\n--- a/src/libcamera/camera_manager.cpp\n+++ b/src/libcamera/camera_manager.cpp\n@@ -212,15 +212,17 @@ void CameraManager::addCamera(std::shared_ptr camera)\n */\n void CameraManager::removeCamera(Camera *camera)\n {\n-\tfor (auto iter = cameras_.begin(); iter != cameras_.end(); ++iter) {\n-\t\tif (iter->get() == camera) {\n-\t\t\tLOG(Camera, Debug)\n-\t\t\t\t<< \"Unregistering camera '\"\n-\t\t\t\t<< camera->name() << \"'\";\n-\t\t\tcameras_.erase(iter);\n-\t\t\treturn;\n-\t\t}\n-\t}\n+\tauto iter = std::find_if(cameras_.begin(), cameras_.end(),\n+\t\t\t\t [camera](std::shared_ptr &c) {\n+\t\t\t\t\treturn c.get() == camera;\n+\t\t\t\t });\n+\tif (iter == cameras_.end())\n+\t\treturn;\n+\n+\tLOG(Camera, Debug)\n+\t\t<< \"Unregistering camera '\" << camera->name() << \"'\";\n+\n+\tcameras_.erase(iter);\n }\n\n /**\n\n(untested) and an additional std::find_if at the end for\ncamerasByDevnum_.\n\n> \n> /**\n> diff --git a/src/libcamera/include/pipeline_handler.h b/src/libcamera/include/pipeline_handler.h\n> index f3622631..067baef5 100644\n> --- a/src/libcamera/include/pipeline_handler.h\n> +++ b/src/libcamera/include/pipeline_handler.h\n> @@ -12,6 +12,7 @@\n> #include \n> #include \n> #include \n> +#include \n> #include \n> \n> #include \n> @@ -86,7 +87,7 @@ public:\n> \n> protected:\n> \tvoid registerCamera(std::shared_ptr camera,\n> -\t\t\t std::unique_ptr data);\n> +\t\t\t std::unique_ptr data, dev_t devnum = 0);\n> \tvoid hotplugMediaDevice(MediaDevice *media);\n> \n> \tvirtual int queueRequestDevice(Camera *camera, Request *request) = 0;\n> diff --git a/src/libcamera/pipeline_handler.cpp b/src/libcamera/pipeline_handler.cpp\n> index 5badf31c..942b1a30 100644\n> --- a/src/libcamera/pipeline_handler.cpp\n> +++ b/src/libcamera/pipeline_handler.cpp\n> @@ -7,6 +7,8 @@\n> \n> #include \"pipeline_handler.h\"\n> \n> +#include \n> +\n> #include \n> #include \n> #include \n> @@ -438,19 +440,26 @@ void PipelineHandler::completeRequest(Camera *camera, Request *request)\n> * \\brief Register a camera to the camera manager and pipeline handler\n> * \\param[in] camera The camera to be added\n> * \\param[in] data Pipeline-specific data for the camera\n> + * \\param[in] devnum Device number of the camera (optional)\n> *\n> * This method is called by pipeline handlers to register the cameras they\n> * handle with the camera manager. It associates the pipeline-specific \\a data\n> * with the camera, for later retrieval with cameraData(). Ownership of \\a data\n> * is transferred to the PipelineHandler.\n> + *\n> + * \\a devnum is the device number (as returned by makedev) that the \\a camera\n> + * is to be associated with. This is for the V4L2 compatibility layer to map\n> + * device nodes to libcamera Camera instances based on the device number\n\ns/libcamera //\n\n> + * registered by this method in \\a devnum.\n> */\n> void PipelineHandler::registerCamera(std::shared_ptr camera,\n> -\t\t\t\t std::unique_ptr data)\n> +\t\t\t\t std::unique_ptr data,\n> +\t\t\t\t dev_t devnum)\n> {\n> \tdata->camera_ = camera.get();\n> \tcameraData_[camera.get()] = std::move(data);\n> \tcameras_.push_back(camera);\n> -\tmanager_->addCamera(std::move(camera));\n> +\tmanager_->addCamera(std::move(camera), devnum);\n> }\n> \n> /**\n\nWith the above issues addressed,\n\nReviewed-by: Laurent Pinchart ","headers":{"Return-Path":"","Received":["from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[213.167.242.64])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 55D2860467\n\tfor ;\n\tThu, 2 Jan 2020 01:46:45 +0100 (CET)","from pendragon.ideasonboard.com (81-175-216-236.bb.dnainternet.fi\n\t[81.175.216.236])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id B200F516;\n\tThu, 2 Jan 2020 01:46:44 +0100 (CET)"],"DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1577926004;\n\tbh=W+Rv0usl1Ldhr7V4IU+a0WXW6LdE2WwpMfjNv6p1KS4=;\n\th=Date:From:To:Cc:Subject:References:In-Reply-To:From;\n\tb=byd8ilWuKJ5n19lAP/n/PACxFFKQAXQZVGdnZK0/ONkmXfNd3GZp3xEnaxo6UbG8h\n\tCX7RaPhWxQ+FE3gI+tXzx0ph3dbrylc2Sj1XxhQudKIEXEtFAxqrSa5XPQfEDH0bdB\n\tcZcJut5XDCOXL6yfR5RCiDI/pIm0oz4KlHpvgZ64=","Date":"Thu, 2 Jan 2020 02:46:35 +0200","From":"Laurent Pinchart ","To":"Paul Elder ","Cc":"libcamera-devel@lists.libcamera.org","Message-ID":"<20200102004635.GC15498@pendragon.ideasonboard.com>","References":"<20191231053314.20063-1-paul.elder@ideasonboard.com>\n\t<20191231053314.20063-3-paul.elder@ideasonboard.com>","MIME-Version":"1.0","Content-Type":"text/plain; charset=utf-8","Content-Disposition":"inline","In-Reply-To":"<20191231053314.20063-3-paul.elder@ideasonboard.com>","User-Agent":"Mutt/1.10.1 (2018-07-13)","Subject":"Re: [libcamera-devel] [PATCH v4 2/4] libcamera: camera_manager,\n\tpipeline_handler: allow retrieving cameras by device numbers","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","X-List-Received-Date":"Thu, 02 Jan 2020 00:46:45 -0000"}}]