[{"id":577,"web_url":"https://patchwork.libcamera.org/comment/577/","msgid":"<75b4f13b-0cbe-dee5-2946-1049ec971e51@ideasonboard.com>","date":"2019-01-25T09:27:25","subject":"Re: [libcamera-devel] [PATCH 06/10] libcamera: camera: Add\n\tdisconnection notification","submitter":{"id":4,"url":"https://patchwork.libcamera.org/api/people/4/","name":"Kieran Bingham","email":"kieran.bingham@ideasonboard.com"},"content":"Hi Niklas,\n\nOn 24/01/2019 10:16, Laurent Pinchart wrote:\n> From: Niklas Söderlund \n> \n> As camera object have the potential to outlive the hardware they\n> represent, there is a need to inform the camera that the underlying\n> device has been disconnected, and in turn to notify applications.\n> \n> Implement a disconnection notification mechanism that can be used by\n> pipeline handlers to notify the camera of disconnection. The camera then\n> block all new API calls and emit the disconnected signal.\n> \n> Signed-off-by: Niklas Söderlund \n> Signed-off-by: Laurent Pinchart \n> ---\n> include/libcamera/camera.h | 7 +++++++\n> src/libcamera/camera.cpp | 31 +++++++++++++++++++++++++++++++\n> 2 files changed, 38 insertions(+)\n> \n> diff --git a/include/libcamera/camera.h b/include/libcamera/camera.h\n> index efafb9e28c56..a2ded62de948 100644\n> --- a/include/libcamera/camera.h\n> +++ b/include/libcamera/camera.h\n> @@ -10,6 +10,8 @@\n> #include \n> #include \n> \n> +#include \n> +\n> namespace libcamera {\n> \n> class PipelineHandler;\n> @@ -25,10 +27,15 @@ public:\n> \n> \tconst std::string &name() const;\n> \n> +\tSignal disconnected;\n> +\n> private:\n> \tCamera(PipelineHandler *pipe, const std::string &name);\n> \t~Camera();\n> \n> +\tfriend class PipelineHandler;\n> +\tvoid disconnect();\n> +\n> \tstd::shared_ptr pipe_;\n> \tstd::string name_;\n> };\n> diff --git a/src/libcamera/camera.cpp b/src/libcamera/camera.cpp\n> index 3a531c7e4d8f..9cec289282e4 100644\n> --- a/src/libcamera/camera.cpp\n> +++ b/src/libcamera/camera.cpp\n> @@ -34,6 +34,8 @@\n> \n> namespace libcamera {\n> \n> +LOG_DECLARE_CATEGORY(Camera)\n> +\n> /**\n> * \\class Camera\n> * \\brief Camera device\n> @@ -87,6 +89,18 @@ const std::string &Camera::name() const\n> \treturn name_;\n> }\n> \n> +/**\n> + * \\var Camera::disconnected\n> + * \\brief Signal emitted when the camera is disconnected from the system\n> + *\n> + * This signal is emitted when libcamera detects that the cameera has been\n> + * removed from the system. For hot-pluggable devices this is usually caused by\n> + * physical device disconnection. The media device is passed as a parameter.\n> + *\n> + * As soon as this signal is emitted the camera instance will refuse all new\n> + * application API calls by returning errors immediately.\n> + */\n> +\n> Camera::Camera(PipelineHandler *pipe, const std::string &name)\n> \t: pipe_(pipe->shared_from_this()), name_(name)\n> {\n> @@ -96,4 +110,21 @@ Camera::~Camera()\n> {\n> }\n> \n> +/**\n> + * \\brief Notify camera disconnection\n> + *\n> + * This method is used to notify the camera instance that the underlying\n> + * hardware has been unplugged. In response to the disconnection the camera\n> + * instance notifies the application by emitting the #disconnected signal, and\n> + * ensures that all new calls to the application-facing Camera API return an\n> + * error immediately.\n> + */\n> +void Camera::disconnect()\n> +{\n> +\tLOG(Camera, Debug) << \"Disconnecting camera \" << name_;\n> +\n> +\t/** \\todo Block API calls when they will be implemented. */\n> +\tdisconnected.emit(this);\n\nIf only we could have a python function decorator syntax:\n\n@fail_if_disconnected\n\nwhich would do a pre-check on 'if (!connected) return -ENODEV;' before\nthe function was called...\n\nI had a quick look at how to emulate function decorators in C++. It's\nnot pretty - lets just have checks at the beginning of the functions\nnecessary :)\n\n--\nKieran\n\n\n> +}\n> +\n> } /* namespace libcamera */\n>","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 79FBE60C7F\n\tfor ;\n\tFri, 25 Jan 2019 10:27:28 +0100 (CET)","from [192.168.0.21]\n\t(cpc89242-aztw30-2-0-cust488.18-1.cable.virginm.net [86.31.129.233])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id E26AC325;\n\tFri, 25 Jan 2019 10:27:27 +0100 (CET)"],"DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1548408448;\n\tbh=AkV3af6HmjhjaijeDiNmF697fvSManfY2zQXjOTpoOo=;\n\th=Reply-To:Subject:To:References:From:Date:In-Reply-To:From;\n\tb=OZRvjhrB8CbUXNmx3ZKjwEwOtUBd4F8sMy+Std3A9X6IqlpV1sVx7IFWs72vONqFA\n\tJrRexlUCPAKzuh0av612q+fHqIzY64zelHISBloUvd04LP7FJ+nuGFjs+tcNMwzGoq\n\tozjF3TEm/3erSBQ4x7Ab367hImn4vhptGPaXPSuc=","Reply-To":"kieran.bingham@ideasonboard.com","To":"Laurent Pinchart ,\n\tlibcamera-devel@lists.libcamera.org","References":"<20190124101651.9993-1-laurent.pinchart@ideasonboard.com>\n\t<20190124101651.9993-7-laurent.pinchart@ideasonboard.com>","From":"Kieran Bingham ","Openpgp":"preference=signencrypt","Autocrypt":"addr=kieran.bingham@ideasonboard.com; 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Linux x86_64; rv:60.0) Gecko/20100101\n\tThunderbird/60.2.1","MIME-Version":"1.0","In-Reply-To":"<20190124101651.9993-7-laurent.pinchart@ideasonboard.com>","Content-Type":"text/plain; charset=utf-8","Content-Language":"en-GB","Content-Transfer-Encoding":"8bit","Subject":"Re: [libcamera-devel] [PATCH 06/10] libcamera: camera: Add\n\tdisconnection notification","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.23","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","X-List-Received-Date":"Fri, 25 Jan 2019 09:27:28 -0000"}}]