{"id":4029,"url":"https://patchwork.libcamera.org/api/1.1/patches/4029/?format=json","web_url":"https://patchwork.libcamera.org/patch/4029/","project":{"id":1,"url":"https://patchwork.libcamera.org/api/1.1/projects/1/?format=json","name":"libcamera","link_name":"libcamera","list_id":"libcamera_core","list_email":"libcamera-devel@lists.libcamera.org","web_url":"","scm_url":"","webscm_url":""},"msgid":"<20200611171528.9381-5-email@uajain.com>","date":"2020-06-11T17:16:07","name":"[libcamera-devel,v4,4/6] libcamera: camera_manager: Introduce signals when a camera is added/removed","commit_ref":null,"pull_url":null,"state":"superseded","archived":false,"hash":"ae55e7c3bf01699b3eb4febdcd065927dc9456bf","submitter":{"id":1,"url":"https://patchwork.libcamera.org/api/1.1/people/1/?format=json","name":"Umang Jain","email":"email@uajain.com"},"delegate":null,"mbox":"https://patchwork.libcamera.org/patch/4029/mbox/","series":[{"id":993,"url":"https://patchwork.libcamera.org/api/1.1/series/993/?format=json","web_url":"https://patchwork.libcamera.org/project/libcamera/list/?series=993","date":"2020-06-11T17:16:02","name":"Introduce UVC hotplugging support","version":4,"mbox":"https://patchwork.libcamera.org/series/993/mbox/"}],"comments":"https://patchwork.libcamera.org/api/patches/4029/comments/","check":"pending","checks":"https://patchwork.libcamera.org/api/patches/4029/checks/","tags":{},"headers":{"Return-Path":"","Received":["from o1.f.az.sendgrid.net (o1.f.az.sendgrid.net [208.117.55.132])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 28ABD61DD5\n\tfor ;\n\tThu, 11 Jun 2020 19:16:09 +0200 (CEST)","by filter0090p3las1.sendgrid.net with SMTP id\n\tfilter0090p3las1-14468-5EE266D6-EC\n\t2020-06-11 17:16:07.203653683 +0000 UTC m=+255693.521769057","from mail.uajain.com (unknown)\n\tby ismtpd0006p1maa1.sendgrid.net (SG) with ESMTP\n\tid lvWJsPnVQbmps2Y_IfyTlQ Thu, 11 Jun 2020 17:16:06.142 +0000 (UTC)"],"Authentication-Results":"lancelot.ideasonboard.com; dkim=pass (1024-bit key; \n\tunprotected) header.d=uajain.com\n\theader.i=@uajain.com header.b=\"QxgbcBH4\"; \n\tdkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed; d=uajain.com;\n\th=from:subject:in-reply-to:references:mime-version:to:cc:\n\tcontent-transfer-encoding:content-type;\n\ts=s1; bh=uCl/J67FgCo4M0iTjSjYFrrXNUOL4Xij4N/9uBG8uWg=;\n\tb=QxgbcBH4+NExzcmrIKlSF31HSYbqDxvW3SB6SI5oI0Vd6iEqnfQzwqSKzjH8tIJyuG2n\n\t0sYGgX3ZWz6Uvwy5ybXdt08JryNFVvCBlgJ+/LfdoLvG2pAp4ZXvdIvnGZCeN6/Buud1qy\n\tjGIC7LFh2ODlm28cHgwzIQ3On3t5z/33Y=","From":"Umang Jain ","Date":"Thu, 11 Jun 2020 17:16:07 +0000 (UTC)","Message-Id":"<20200611171528.9381-5-email@uajain.com>","In-Reply-To":"<20200611171528.9381-1-email@uajain.com>","References":"<20200611171528.9381-1-email@uajain.com>","Mime-Version":"1.0","X-SG-EID":"1Q40EQ7YGir8a9gjSIAdTjhngY657NMk9ckeo4dbHZDiOpywc/L3L9rFqlwE4KPc1jYMYoB2JcJvIPCLN/wEG610TgdcqfhdUUmOwh3OVHUvLG4JLQNOjA55evh7qLtED5wbsJ1FUDfsK1LNzyi2h/VYO26X5F1UGd0nXCLPVdgFI3SBgr7ie1Esq4seniqlzP/BBNUTzW5L0sDtVwsN3yuuEbeZMUq2vWqksJfEvXQ4LX/ABn9dtvfwcWh0R++e","To":"laurent.pinchart@ideasonboard.com, libcamera-devel@lists.libcamera.org","Content-Transfer-Encoding":"7bit","Content-Type":"text/plain; charset=us-ascii","Subject":"[libcamera-devel] [PATCH v4 4/6] libcamera: camera_manager:\n\tIntroduce signals when a camera is added/removed","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, 11 Jun 2020 17:16:09 -0000"},"content":"Emit 'cameraAdded' and 'cameraRemoved' from CameraManager to enable\nhotplug and hot-unplug support in application like QCam.\n\nTo avoid use-after-free race between the CameraManager and the\napplication, emit the 'cameraRemoved' with the shared_ptr version\nof . This requires to change the function signature of\nCameraManager::removeCamera() API.\n\nAlso, until now, CameraManager::Private::addCamera() transfers the\nentire ownership of camera shared_ptr to CameraManager using std::move().\nThis patch changes the signature of Private::addCamera to accept pass-by-value\ncamera parameter. It is done to make it clear from the caller point of view\nthat the pointer within the caller will still be valid after this function\nreturns. With this change in, we can emit the camera pointer via 'cameraAdded'\nsignal without hitting a segfault.\n\nSigned-off-by: Umang Jain \nReviewed-by: Laurent Pinchart \n---\n include/libcamera/camera_manager.h | 6 ++++-\n src/libcamera/camera_manager.cpp | 38 ++++++++++++++++++++++++++----\n src/libcamera/pipeline_handler.cpp | 2 +-\n 3 files changed, 40 insertions(+), 6 deletions(-)","diff":"diff --git a/include/libcamera/camera_manager.h b/include/libcamera/camera_manager.h\nindex 95dc636..9eb2b6f 100644\n--- a/include/libcamera/camera_manager.h\n+++ b/include/libcamera/camera_manager.h\n@@ -13,6 +13,7 @@\n #include \n \n #include \n+#include \n \n namespace libcamera {\n \n@@ -36,13 +37,16 @@ public:\n \n \tvoid addCamera(std::shared_ptr camera,\n \t\t const std::vector &devnums);\n-\tvoid removeCamera(Camera *camera);\n+\tvoid removeCamera(std::shared_ptr camera);\n \n \tstatic const std::string &version() { return version_; }\n \n \tvoid setEventDispatcher(std::unique_ptr dispatcher);\n \tEventDispatcher *eventDispatcher();\n \n+\tSignal> cameraAdded;\n+\tSignal> cameraRemoved;\n+\n private:\n \tstatic const std::string version_;\n \tstatic CameraManager *self_;\ndiff --git a/src/libcamera/camera_manager.cpp b/src/libcamera/camera_manager.cpp\nindex 17a4afb..7f846c0 100644\n--- a/src/libcamera/camera_manager.cpp\n+++ b/src/libcamera/camera_manager.cpp\n@@ -36,7 +36,7 @@ public:\n \tPrivate(CameraManager *cm);\n \n \tint start();\n-\tvoid addCamera(std::shared_ptr &camera,\n+\tvoid addCamera(std::shared_ptr camera,\n \t\t const std::vector &devnums);\n \tvoid removeCamera(Camera *camera);\n \n@@ -172,7 +172,7 @@ void CameraManager::Private::cleanup()\n \tenumerator_.reset(nullptr);\n }\n \n-void CameraManager::Private::addCamera(std::shared_ptr &camera,\n+void CameraManager::Private::addCamera(std::shared_ptr camera,\n \t\t\t\t const std::vector &devnums)\n {\n \tMutexLocker locker(mutex_);\n@@ -375,6 +375,34 @@ std::shared_ptr CameraManager::get(dev_t devnum)\n \treturn iter->second.lock();\n }\n \n+/**\n+ * \\var CameraManager::cameraAdded\n+ * \\brief Notify of a new camera added to the system\n+ *\n+ * This signal is emitted when a new camera is detected and successfully handled\n+ * by the camera manager. The notification occurs alike for cameras detected\n+ * when the manager is started with start() or when new cameras are later\n+ * connected to the system. When the signal is emitted the new camera is already\n+ * available from the list of cameras().\n+ *\n+ * The signal is emitted from the CameraManager thread. Applications shall\n+ * minimize the time spent in the signal handler and shall in particular not\n+ * perform any blocking operation.\n+ */\n+\n+/**\n+ * \\var CameraManager::cameraRemoved\n+ * \\brief Notify of a new camera removed from the system\n+ *\n+ * This signal is emitted when a camera is removed from the system. When the\n+ * signal is emitted the camera is not available from the list of cameras()\n+ * anymore.\n+ *\n+ * The signal is emitted from the CameraManager thread. Applications shall\n+ * minimize the time spent in the signal handler and shall in particular not\n+ * perform any blocking operation.\n+ */\n+\n /**\n * \\brief Add a camera to the camera manager\n * \\param[in] camera The camera to be added\n@@ -395,6 +423,7 @@ void CameraManager::addCamera(std::shared_ptr camera,\n \tASSERT(Thread::current() == p_.get());\n \n \tp_->addCamera(camera, devnums);\n+\tcameraAdded.emit(camera);\n }\n \n /**\n@@ -407,11 +436,12 @@ void CameraManager::addCamera(std::shared_ptr camera,\n *\n * \\context This function shall be called from the CameraManager thread.\n */\n-void CameraManager::removeCamera(Camera *camera)\n+void CameraManager::removeCamera(std::shared_ptr camera)\n {\n \tASSERT(Thread::current() == p_.get());\n \n-\tp_->removeCamera(camera);\n+\tp_->removeCamera(camera.get());\n+\tcameraRemoved.emit(camera);\n }\n \n /**\ndiff --git a/src/libcamera/pipeline_handler.cpp b/src/libcamera/pipeline_handler.cpp\nindex a0f6b0f..bad79dc 100644\n--- a/src/libcamera/pipeline_handler.cpp\n+++ b/src/libcamera/pipeline_handler.cpp\n@@ -565,7 +565,7 @@ void PipelineHandler::disconnect()\n \t\t\tcontinue;\n \n \t\tcamera->disconnect();\n-\t\tmanager_->removeCamera(camera.get());\n+\t\tmanager_->removeCamera(camera);\n \t}\n \n \tcameras_.clear();\n","prefixes":["libcamera-devel","v4","4/6"]}