From patchwork Thu Jun 11 17:16:07 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Umang Jain X-Patchwork-Id: 4029 Return-Path: Received: from o1.f.az.sendgrid.net (o1.f.az.sendgrid.net [208.117.55.132]) by lancelot.ideasonboard.com (Postfix) with ESMTPS id 28ABD61DD5 for ; Thu, 11 Jun 2020 19:16:09 +0200 (CEST) Authentication-Results: lancelot.ideasonboard.com; dkim=pass (1024-bit key; unprotected) header.d=uajain.com header.i=@uajain.com header.b="QxgbcBH4"; dkim-atps=neutral DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=uajain.com; h=from:subject:in-reply-to:references:mime-version:to:cc: content-transfer-encoding:content-type; s=s1; bh=uCl/J67FgCo4M0iTjSjYFrrXNUOL4Xij4N/9uBG8uWg=; b=QxgbcBH4+NExzcmrIKlSF31HSYbqDxvW3SB6SI5oI0Vd6iEqnfQzwqSKzjH8tIJyuG2n 0sYGgX3ZWz6Uvwy5ybXdt08JryNFVvCBlgJ+/LfdoLvG2pAp4ZXvdIvnGZCeN6/Buud1qy jGIC7LFh2ODlm28cHgwzIQ3On3t5z/33Y= Received: by filter0090p3las1.sendgrid.net with SMTP id filter0090p3las1-14468-5EE266D6-EC 2020-06-11 17:16:07.203653683 +0000 UTC m=+255693.521769057 Received: from mail.uajain.com (unknown) by ismtpd0006p1maa1.sendgrid.net (SG) with ESMTP id lvWJsPnVQbmps2Y_IfyTlQ Thu, 11 Jun 2020 17:16:06.142 +0000 (UTC) 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 Subject: [libcamera-devel] [PATCH v4 4/6] libcamera: camera_manager: Introduce 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: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 11 Jun 2020 17:16:09 -0000 Emit 'cameraAdded' and 'cameraRemoved' from CameraManager to enable hotplug and hot-unplug support in application like QCam. To avoid use-after-free race between the CameraManager and the application, emit the 'cameraRemoved' with the shared_ptr version of . This requires to change the function signature of CameraManager::removeCamera() API. Also, until now, CameraManager::Private::addCamera() transfers the entire ownership of camera shared_ptr to CameraManager using std::move(). This patch changes the signature of Private::addCamera to accept pass-by-value camera parameter. It is done to make it clear from the caller point of view that the pointer within the caller will still be valid after this function returns. With this change in, we can emit the camera pointer via 'cameraAdded' signal without hitting a segfault. Signed-off-by: Umang Jain Reviewed-by: Laurent Pinchart --- include/libcamera/camera_manager.h | 6 ++++- src/libcamera/camera_manager.cpp | 38 ++++++++++++++++++++++++++---- src/libcamera/pipeline_handler.cpp | 2 +- 3 files changed, 40 insertions(+), 6 deletions(-) diff --git a/include/libcamera/camera_manager.h b/include/libcamera/camera_manager.h index 95dc636..9eb2b6f 100644 --- a/include/libcamera/camera_manager.h +++ b/include/libcamera/camera_manager.h @@ -13,6 +13,7 @@ #include #include +#include namespace libcamera { @@ -36,13 +37,16 @@ public: void addCamera(std::shared_ptr camera, const std::vector &devnums); - void removeCamera(Camera *camera); + void removeCamera(std::shared_ptr camera); static const std::string &version() { return version_; } void setEventDispatcher(std::unique_ptr dispatcher); EventDispatcher *eventDispatcher(); + Signal> cameraAdded; + Signal> cameraRemoved; + private: static const std::string version_; static CameraManager *self_; diff --git a/src/libcamera/camera_manager.cpp b/src/libcamera/camera_manager.cpp index 17a4afb..7f846c0 100644 --- a/src/libcamera/camera_manager.cpp +++ b/src/libcamera/camera_manager.cpp @@ -36,7 +36,7 @@ public: Private(CameraManager *cm); int start(); - void addCamera(std::shared_ptr &camera, + void addCamera(std::shared_ptr camera, const std::vector &devnums); void removeCamera(Camera *camera); @@ -172,7 +172,7 @@ void CameraManager::Private::cleanup() enumerator_.reset(nullptr); } -void CameraManager::Private::addCamera(std::shared_ptr &camera, +void CameraManager::Private::addCamera(std::shared_ptr camera, const std::vector &devnums) { MutexLocker locker(mutex_); @@ -375,6 +375,34 @@ std::shared_ptr CameraManager::get(dev_t devnum) return iter->second.lock(); } +/** + * \var CameraManager::cameraAdded + * \brief Notify of a new camera added to the system + * + * This signal is emitted when a new camera is detected and successfully handled + * by the camera manager. The notification occurs alike for cameras detected + * when the manager is started with start() or when new cameras are later + * connected to the system. When the signal is emitted the new camera is already + * available from the list of cameras(). + * + * The signal is emitted from the CameraManager thread. Applications shall + * minimize the time spent in the signal handler and shall in particular not + * perform any blocking operation. + */ + +/** + * \var CameraManager::cameraRemoved + * \brief Notify of a new camera removed from the system + * + * This signal is emitted when a camera is removed from the system. When the + * signal is emitted the camera is not available from the list of cameras() + * anymore. + * + * The signal is emitted from the CameraManager thread. Applications shall + * minimize the time spent in the signal handler and shall in particular not + * perform any blocking operation. + */ + /** * \brief Add a camera to the camera manager * \param[in] camera The camera to be added @@ -395,6 +423,7 @@ void CameraManager::addCamera(std::shared_ptr camera, ASSERT(Thread::current() == p_.get()); p_->addCamera(camera, devnums); + cameraAdded.emit(camera); } /** @@ -407,11 +436,12 @@ void CameraManager::addCamera(std::shared_ptr camera, * * \context This function shall be called from the CameraManager thread. */ -void CameraManager::removeCamera(Camera *camera) +void CameraManager::removeCamera(std::shared_ptr camera) { ASSERT(Thread::current() == p_.get()); - p_->removeCamera(camera); + p_->removeCamera(camera.get()); + cameraRemoved.emit(camera); } /** diff --git a/src/libcamera/pipeline_handler.cpp b/src/libcamera/pipeline_handler.cpp index a0f6b0f..bad79dc 100644 --- a/src/libcamera/pipeline_handler.cpp +++ b/src/libcamera/pipeline_handler.cpp @@ -565,7 +565,7 @@ void PipelineHandler::disconnect() continue; camera->disconnect(); - manager_->removeCamera(camera.get()); + manager_->removeCamera(camera); } cameras_.clear();